CA1132321A - Injection molding filter assembly - Google Patents
Injection molding filter assemblyInfo
- Publication number
- CA1132321A CA1132321A CA332,292A CA332292A CA1132321A CA 1132321 A CA1132321 A CA 1132321A CA 332292 A CA332292 A CA 332292A CA 1132321 A CA1132321 A CA 1132321A
- Authority
- CA
- Canada
- Prior art keywords
- channels
- filter assembly
- outer member
- lands
- torpedo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000001746 injection moulding Methods 0.000 title claims abstract description 12
- 238000001914 filtration Methods 0.000 claims abstract description 36
- 239000000155 melt Substances 0.000 claims abstract description 17
- 239000012535 impurity Substances 0.000 claims description 8
- 238000010079 rubber tapping Methods 0.000 claims description 2
- 238000004140 cleaning Methods 0.000 claims 2
- 239000000356 contaminant Substances 0.000 abstract description 9
- 238000000465 moulding Methods 0.000 abstract description 7
- 230000000737 periodic effect Effects 0.000 abstract 1
- 239000000463 material Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- DMFGNRRURHSENX-UHFFFAOYSA-N beryllium copper Chemical compound [Be].[Cu] DMFGNRRURHSENX-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 239000011111 cardboard Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000012778 molding material Substances 0.000 description 1
- 239000000123 paper Substances 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- -1 string Substances 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/20—Injection nozzles
- B29C45/24—Cleaning equipment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/44—Edge filtering elements, i.e. using contiguous impervious surfaces
Abstract
This invention relates to an improved injection molding filter assembly to be located between the molding machine and the mold. The assembly has an elongated inner torpedo member with a generally cylindrical outer surface which is centrally located in a passage through a hollow outer member. The passage is defined by a generally cylindrical inner wall which is interrupted by an even number of inwardly opening longitudinally extending channels. Inlet channels extending from the inlet of the assembly and dead ending adjacent the outlet alternate with outlet channels extending from the outlet of the assembly and dead ending adjacent the inlet. Filtering apertures are formed between the outer surface of the torpedo member and the lands between the inlet and outlet channels through which the melt flows from the inlet channels to the outlet channels. A single elongated aperture may be formed at each land or a plurality of smaller apertures may be formed by providing alternating laterally extending ridges and grooves on the inner surfaces of the lands and/or on the outer surface of the torpedo member. Contaminants which are too large to pass through the filtering apertures accumulate adjacent the dead ends of the inlet channels. The outer member has a collar portion which may be detached to take out the torpedo member for periodic removal of accumulated contaminants. The location of the channels in the outer member provides improved heat flow characteristics and allows the width of the filtering slits to be quickly and easily changed by substituting a relatively inexpensive torpedo member having a different diameter.
Description
1~3Z3;~
This invention relates generally to injection molding and more particularly to an improved filter assembly through which hot molten plastic material passes from the molding machine to the manifold or mold.
The hot molten plastic material or melt may contain contaminants such as wood, paper, cardboard, iron, string, steel or brass which may plug the gates or interfere with operation of the valve pins, thus resulting in costly loss of pro-duction. Consequently, it is highly desirable to be able tofilter the melt as it leaves the molding machine. In the past, various devices have been used for this purpose. Thin mesh screens located in front of orficed retaining plates have the disadvantage that the screen may break down and itself become a contaminant. Other devices such as radial filters have a considerable number of parts and accordingly are costly to manufacture and replace. Others have been provided with purging mechanisms, but these similarly have the disadvantage of being relatively costly and are subject to malfunction. The applicant's previous United States Patent 4,046,359 dated September 6, 1977 discloses an injection molding filter assembly which deals with these problems and while it makes substantial improvements, there are still disadvantages remaining.
A very considerable concern is to be able to pass a large volume of melt through the filter in a sllort period of time when injection is occurring. This is difficult in view of the restricted size of openings re~uired in order to filter the contaminants from the melt. This problem is dealt with in U.S.
Patent 4,097,216 to Putkowski dated June 27, 1978 by elongating the filtering openings between the cylindrical outer body member Z~
1 and a fluted inner torpedo member. While also providing substantial improvements, this filter assembly similarly has remaining disadvantages.
A major concern in injection molding is even control of the melt temperature. A drop in temperature in some areas may result in uneven flow and increasing overall temperatures to compensate for this may lead to break down of the melt. In the present case, it is important that there be no drop in melt temperature in the flow areas furthest removed from the filtering openings or undesirable dead spots may occur. This is particu-larly important in the slots or channels where the filtered contaminants build up. Depending upon the size of the filtering areas or slits, the size of the slots or channels may be very important in permitting sufficient melt flow without undesirable pressure drop. Another disadvantage of the previous filter assembly is that the size of the filtering area or slit cannot be changed by simply replacing a relatively inexpensive inner torpedo member by one of a different size. In order to filter different materials for different applications, it is necessary that it be possible to change to a number of different filtering sizes and thus the cost of stocking the different torpedo members becomes an important factor.
Other practical difficulties in this art are the avoidance of dead spots at the inlet and outlet and accurate location of the torpedo member.
Accordingly, it is an object of the present invention to at least partially overcome these disadvantages by providing an improved injection molding filter assembly providing longi~
tudinal filtering slits between a fluted outer member and a generally cylindrical inner torpedo member.
Z3Z~
1 To this end, in one of its aspects, this invention provides an improved injection molding filter assembly to filter pressurized melt flowing therethrough comprising an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands all being located an equal distance from the central axis along their length, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other inter-vening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and an elongated inner torpedo member centrally located in the outer member, having a generally cylindrical outer surface which is smaller in ~d,~-d~a~4~e~ by a predetermined amount than the said distance of the lands from the said central axis to form a number of elongated filtering slits between the outer surface of the inner member and said lands through which the melt flows from the inlet channels to the outlet channels, the inner torpedo member being longitudinally secured to have the cylindrical outer surface extend at least between the first and second blind ends~ impurities too large to pass through the filtering slits being accumulated at the blind ends of the inlet channels.
Further objects and advantages of the invention will.
appear from the description taken together with the accompanying drawings in which:
Fig. 1 is a partial sectional view of the valve gated injection molding system utilizing an improved filter assembly 1 according to the invention;
Fig. 2 is an exploded partially broken away perspective view of a filter assembly according to a first embodiment~of the invention;
Fig. 3 is a cross sectional view of the filter assembly seen in Fig. 2;
Fig. 4 is a longitudinal section of the filter assembly taken along line IV - IV in Fig. 3;
Fig. 5 is a perspective view of a central portion of the filter assembly seen in Fig. 2 broken out to show the direction of flow of the melt;
Fig. 6 is a cross sectional view similar to Fig. 3, showing a filter assembly having a configuration according to an alternate embodiment of the invention; and Fig. 7 (located on page with Fig. 2) is a perspective view of an inner torpedo member according to a further embodiment of the invention.
Reference is first made to Fig. 1 which shows a valve gating injection molding system having a filter assembly 10 ~O located between the molding machine 12 and the back plate 14.
The hot runner passage 16 extends from the filter assembly 10, through the back plate 14, through the bushing seal 18 received in the heater cast 20, around the stem of the valve pin 22, through the gate 24 and into the cavity 26. The heater cast 20 is formed of beryllium copper and has an electrical heating element 28 and a nozzle portion 30. The heater cast 20 is positioned in the cavity plate 32 by insulation bushing 34. The valve pin 22 is actuated by rocker arm 36 which is driven by piston 38.
Reference is now made to Fig. 2 which shows a filter 23Z~
1 assembly 10 having an elongated hollow outer member 40 and an elongated inner torpedo member 42. The hollow outer member 40 has a body portion 44 and a removable torpedo retaining collar portion 46. The outer member 40 has a central passage 48 there-through defined by generally cylindrical inner surface 50 from which are recessed an even number of radially spaced inwardly opening longitudinally extending channels; alternately, inlet channels 52 and outlet channels 54. The inlet channels 52 and outlet channels 54 extend generally parallel to each other and define therebetween narrow elongated lands 56 of inner surface 50.
The outer member 40 has an inlet end 58 with sloping surfaces 60 defining an inlet opening 62. The inlet end 58 of the outer member 40 is threaded to securely connect it to the molding machine 12. An outlet end 66 of the outer member 40 is provided by the retaining collar portion 46 which defines an outlet opening 68 therethrough. The curved outer face 70 is shaped to be securely received in the back plate 14.
As may be seen, the inlet channels 52 extend from the inlet opening 62, but stop short of the outlet opening 68. On the other hand, the outlet channels 54 have a sloping portion 72 extending from the outlet opening 68 in the collar portion 46 of the outer member 40. The collar portion 46 is removably secured to the body portion 44 by threads 74 which are dimensioned so that the sloping portion 72 of the outlet channels 54 line up respectively with the remaining portions 76 of the outlet channels 54, which stop short of the inlet opening 62.
The inner torpedo mernber 42 has a generally cylindrical outer surface 78 which is smaller in diameter than cylindrical inner surface 50 of the outer member 40 by a predetermined amount. The torpedo member 42 has first and second conical 113 ~
1 ends 80, 82 which, in this embodiment, extend from raised cylindrical centering portions 84, 86 of the surface of the torpedo member 42. Wpon assembly of the torpedo member 42 in the hollow outer member 40, the torpedo member 42 is restricted against axial movement by the abutment of the first conical end 80 on the conical surfaces 88 extending from the inner surface 50 of the body portion 44 of the outer member 40, and by the abutment of second conical end 82 on conical surfaces 90 of the retaining collar portion 46. The raised cylindrical portions 84, 86 of the surface of the torpedo member 42 abut on the cylindrical inner surface 50 to ensure that the torpedo member 42 is centrally located in the passage 48 to thereby form elongated filtering slits 92 having a uniform width between the outer surface 78 of the inner torpedo member 42 and the lands 56 of the outer member 40. In order to ensure that all of the melt passing through the assembly is filtered, the inner torpedo member must be located so that the cylindrical outer surface 78 (including raised portions 84, 86) extends at least from the dead ends 94 of the .
outlet channels 54 to the dead ends 96 of the inlet channels 52.
All components are made of H13 steel, although other materials having sufficient strength, durability, and suitable heat transfer characteristics may also be used.
In use, the body portion 44 of the outer member 40 is screwed into the molding machine 12 and the torpedo member is inserted into it. The retaining collar portion 46 is then screwed on and a predetermined torque is applied to ensure that the sloping portions 72 of the outlet channels 54 are in alignment with the respective remaining portions, at which time the conical ends 80, 82 of the torpedo member 42 are abutting respectively on the conical surfaces 88, 90. The filter assembly 10 is then 113~23~
1 positioned against the back plate 14 and molding begins. The pressurized melt from the lding machine 12 is directed by sloping surfaces 60 to flow smoothly into inlet channels 52. As best seen in Figs. 3 and 5, the melt cannot pass through the inlet channels 52 due to dead ends 96 and therefore it flows circumferentially around the outer surface 78 of the torpedo member 42 through the filtering slits 92 and into the adjacent outlet channels 54. The contaminants which are too large to pass through the filtering slits 92 are carried along the inlet channels 52 and accumulate adjacent the dead ends 96. The filtered melt flows smoothly from the outlet channels 54 through the outlet opening 6g into the hot runner passage 16.
The large cross sectional area of the filtering slits 92 ensures that there is a relatively low pressure drop through the filter assembly even when the inlet channels 52 become partially filled with accumulated contaminants. The total cross sectional area of the inlet channels 52 and the outlet channels 5g may be increased by increasing the diameter of the outer member 40 and the total area of the filtering slits may accor-29 dingly be increased by increasing the length of the filterassembl~. Furthermore, the inlet and outlet structure of the filter assembly provides for smooth flow of the melt through the assembly and avoids dead spots.
After an extended period of use, the accumulated con-taminants may be quickly and easily removed by unscrewing the retaining collar portion 46 of the outer member 40 and taking out the inner torpedo member 42. If a different application or type of molding material indicates that a different dimension of filtering slit is required, the inner torpedo member 42 may be replaced from stock by a torpedo member having the appropriate 1 diameter. Uniform melt temperature is maintained by the large surface area of the outer member 40 in contact with the melt.
If necessary, additional heating may be supplied by heating elements in or around the walls of the outer member 40.
The filter assembly 10 seen in Fig. 6 is similar in most respects to the embodiment described above and features common to both embodiments are described and illustrated using the same reference numerals. However, as may be seen, the inlet and outlet channels 52, 54 have been substantially increased in cross sectional area. Thus, an increase in the area of the filtering slits 92 between the inner torpedo member 42 and the outer member 40 by lengthening the filter assembly may be accommodated without increasing the pressure drop.
Fig. 7 illustrates an alternate embodiment of inner torpedo members 42. In this embodiment, the generally cylin-drical outer surface 78 is interrupted by a larger number of raised centering portions 98. When assembled, these raised centering portions 98 abut on the cylindrical inner surface 50 of the outer member 40 to ensure that the inner torpedo member 42 is properly located throughout its length. This avoids any changes in the dimensions of the filtering slits 92 due to side-ways flexing of the inner torpedo member 42 under the pressure of the melt.
Although the description of this invention has been given with respect to these particular embodiments, it is not to be construed in a limiting sense. Many variations and modifi-cations will now occur to those skilled in the art. For instance, different numbers of inlet and outlet channels could be used with satisfactory results. For a definition of the invention reference is made to the appended claims.
1~3Z~
SUPPLEMENTARY DISCLOSURE
, In addition to the subject matter described in the principal disclosure, this invention includes other embodiments showing the filtering apertures having differen-t shapes.
The filtering apertures of these further embodiments are shaped to prevent the passage of thin flakes of impurities while otherwise might pass through the elongated slits. To this end, in a further aspect the invention provides an improved injection molding filter assembly to filter pressurized melt flowing therethrough towards a gate comprising an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outle-t opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands each having an inner surface and all being located an equal distance from the central axis, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and a generally cylindrical elongated inner torpedo member having an outer surface, the inner member being centrally located and longitudinally secured in the outer member to extend at least between the first and second blind ends, whereby filtering apertures are defined between the outer surface of the inner member and the inner surfaces of the lands through which the melt flows from the inlet channels to the outlet channels, impurities too large to pass through the filtering apertures being accumu-lated at the blind ends of the inlet channels.
~L3~32~
1 The above and other objects, advantages and features of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings wherein:
Fig~ 8 is a partial section of an isometric view showing another embodiment of the invention;
Fig. 9 is an isometric view of an inner torpedo member according to a further embodiment of the invention; and Fig~ 10 is a partial section of an isometric view showing yet another embodiment of the invention.
Most of the features of the additional embodiments are identical to those of the principal disclosure and therefore common features are described and illustrated using the same reference numerals. In order to avoid redundancy with the principal disclosure, the common structure and function will not again be described in detail.
The embodiment of the invention shown in Figure 8 has an inner torpedo member 42 with a cylindrical outer surface 78 having no raised portions. However, the inner surface 50 of the outer member 40 has alternating ridges 100 and grooves 102 which extend laterally across the lands 56. When assembled, the ridges 100 extend to abut or substantially abut on the outer surface 78 Gf the inner member 42.
In use, the operation is substantially the same as described in the principal disclosure except that the melt must pass through the filtering apertures 92 formed by the grooves 102.
As may be seen, a munber of these apertures 92 are formed on each land rather than a single elongated slit in the firs~
described embodiment. This has the advantage of filtering flakes of impurities which might otherwise be thin enough to pass 113~
1 through the elonga~ed slits if oriented to do so. The dimensions of the grooves are normally a little smaller than the diameter of the gate, for instance, 0.040 inches wide, 0.040 inches deep, with 0.020 inch radius hottom corners, and the ridges 100 are normally thinner than the grooves 102 to provide the maximum number of grooves 102 along each land 56 to maximize capacity and minimize pressure drop.
Another variation is shown in Fig. 9 wherein the lateral ridges 100 and grooves 102 are located on the outer surface 78 of the inner torpedo member 42 and the ridges 100 abut on the smooth inner surfaces 50 of the lands S6. In neither instance would the ridges and grooves normally extend towards the ends past the dead ends 94, 96 of the channels 52, 54 in order to avoid undesirable dead spots. While the ridges 100 and grooves 102 are formed to extend laterally they may also be formed by threading the inner torpedo member 42 or tapping the outer member 40.
Fig. 10 shows still another variation which may be used for certain types of materials and is particularly useful for unusually dirty melt to maximize capacity and minimize the number of clean outs require. In this embodiment, ridges 100 and grooves 102 are formed on both the outer surface 78 of the inner torpedo member 42 and the inner surfaces 50 of the lands ; 56. The ridges 100 and grooves 102 are of substantially equal width, the inner torpedo member is longitudinally located in the outer member 40 so that the ridges of one are in alignment with the grooves of the other, and the tops or surfaces 104 of the ridges of both are of substantially equal diameter, whereby the grooves 102 of both form separate filtering apertures ~2. Once again, ridge an~ groove surfaces are not extended towards the ~"`
~13'~3~
1 ends past the dead ends 94, 9Ç to avoid the formation of dead spots where the melt will collect causing problems of deterior~
ation and on colour change.
The use of this embodiment of the invention is substantially the same as of the foregoing embodiments, except that the filtering capacity is significantly increased due to the increased number and area of filtering apertures.
Still further variations and modifications of the invention will occur to those skilled in the art. For example, different numbers and shapes of filtering apertures could be used with satisfactory results, depending upon the type of material being filtered and other conditions of the particular application of the invention.
` .
, ' .
This invention relates generally to injection molding and more particularly to an improved filter assembly through which hot molten plastic material passes from the molding machine to the manifold or mold.
The hot molten plastic material or melt may contain contaminants such as wood, paper, cardboard, iron, string, steel or brass which may plug the gates or interfere with operation of the valve pins, thus resulting in costly loss of pro-duction. Consequently, it is highly desirable to be able tofilter the melt as it leaves the molding machine. In the past, various devices have been used for this purpose. Thin mesh screens located in front of orficed retaining plates have the disadvantage that the screen may break down and itself become a contaminant. Other devices such as radial filters have a considerable number of parts and accordingly are costly to manufacture and replace. Others have been provided with purging mechanisms, but these similarly have the disadvantage of being relatively costly and are subject to malfunction. The applicant's previous United States Patent 4,046,359 dated September 6, 1977 discloses an injection molding filter assembly which deals with these problems and while it makes substantial improvements, there are still disadvantages remaining.
A very considerable concern is to be able to pass a large volume of melt through the filter in a sllort period of time when injection is occurring. This is difficult in view of the restricted size of openings re~uired in order to filter the contaminants from the melt. This problem is dealt with in U.S.
Patent 4,097,216 to Putkowski dated June 27, 1978 by elongating the filtering openings between the cylindrical outer body member Z~
1 and a fluted inner torpedo member. While also providing substantial improvements, this filter assembly similarly has remaining disadvantages.
A major concern in injection molding is even control of the melt temperature. A drop in temperature in some areas may result in uneven flow and increasing overall temperatures to compensate for this may lead to break down of the melt. In the present case, it is important that there be no drop in melt temperature in the flow areas furthest removed from the filtering openings or undesirable dead spots may occur. This is particu-larly important in the slots or channels where the filtered contaminants build up. Depending upon the size of the filtering areas or slits, the size of the slots or channels may be very important in permitting sufficient melt flow without undesirable pressure drop. Another disadvantage of the previous filter assembly is that the size of the filtering area or slit cannot be changed by simply replacing a relatively inexpensive inner torpedo member by one of a different size. In order to filter different materials for different applications, it is necessary that it be possible to change to a number of different filtering sizes and thus the cost of stocking the different torpedo members becomes an important factor.
Other practical difficulties in this art are the avoidance of dead spots at the inlet and outlet and accurate location of the torpedo member.
Accordingly, it is an object of the present invention to at least partially overcome these disadvantages by providing an improved injection molding filter assembly providing longi~
tudinal filtering slits between a fluted outer member and a generally cylindrical inner torpedo member.
Z3Z~
1 To this end, in one of its aspects, this invention provides an improved injection molding filter assembly to filter pressurized melt flowing therethrough comprising an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands all being located an equal distance from the central axis along their length, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other inter-vening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and an elongated inner torpedo member centrally located in the outer member, having a generally cylindrical outer surface which is smaller in ~d,~-d~a~4~e~ by a predetermined amount than the said distance of the lands from the said central axis to form a number of elongated filtering slits between the outer surface of the inner member and said lands through which the melt flows from the inlet channels to the outlet channels, the inner torpedo member being longitudinally secured to have the cylindrical outer surface extend at least between the first and second blind ends~ impurities too large to pass through the filtering slits being accumulated at the blind ends of the inlet channels.
Further objects and advantages of the invention will.
appear from the description taken together with the accompanying drawings in which:
Fig. 1 is a partial sectional view of the valve gated injection molding system utilizing an improved filter assembly 1 according to the invention;
Fig. 2 is an exploded partially broken away perspective view of a filter assembly according to a first embodiment~of the invention;
Fig. 3 is a cross sectional view of the filter assembly seen in Fig. 2;
Fig. 4 is a longitudinal section of the filter assembly taken along line IV - IV in Fig. 3;
Fig. 5 is a perspective view of a central portion of the filter assembly seen in Fig. 2 broken out to show the direction of flow of the melt;
Fig. 6 is a cross sectional view similar to Fig. 3, showing a filter assembly having a configuration according to an alternate embodiment of the invention; and Fig. 7 (located on page with Fig. 2) is a perspective view of an inner torpedo member according to a further embodiment of the invention.
Reference is first made to Fig. 1 which shows a valve gating injection molding system having a filter assembly 10 ~O located between the molding machine 12 and the back plate 14.
The hot runner passage 16 extends from the filter assembly 10, through the back plate 14, through the bushing seal 18 received in the heater cast 20, around the stem of the valve pin 22, through the gate 24 and into the cavity 26. The heater cast 20 is formed of beryllium copper and has an electrical heating element 28 and a nozzle portion 30. The heater cast 20 is positioned in the cavity plate 32 by insulation bushing 34. The valve pin 22 is actuated by rocker arm 36 which is driven by piston 38.
Reference is now made to Fig. 2 which shows a filter 23Z~
1 assembly 10 having an elongated hollow outer member 40 and an elongated inner torpedo member 42. The hollow outer member 40 has a body portion 44 and a removable torpedo retaining collar portion 46. The outer member 40 has a central passage 48 there-through defined by generally cylindrical inner surface 50 from which are recessed an even number of radially spaced inwardly opening longitudinally extending channels; alternately, inlet channels 52 and outlet channels 54. The inlet channels 52 and outlet channels 54 extend generally parallel to each other and define therebetween narrow elongated lands 56 of inner surface 50.
The outer member 40 has an inlet end 58 with sloping surfaces 60 defining an inlet opening 62. The inlet end 58 of the outer member 40 is threaded to securely connect it to the molding machine 12. An outlet end 66 of the outer member 40 is provided by the retaining collar portion 46 which defines an outlet opening 68 therethrough. The curved outer face 70 is shaped to be securely received in the back plate 14.
As may be seen, the inlet channels 52 extend from the inlet opening 62, but stop short of the outlet opening 68. On the other hand, the outlet channels 54 have a sloping portion 72 extending from the outlet opening 68 in the collar portion 46 of the outer member 40. The collar portion 46 is removably secured to the body portion 44 by threads 74 which are dimensioned so that the sloping portion 72 of the outlet channels 54 line up respectively with the remaining portions 76 of the outlet channels 54, which stop short of the inlet opening 62.
The inner torpedo mernber 42 has a generally cylindrical outer surface 78 which is smaller in diameter than cylindrical inner surface 50 of the outer member 40 by a predetermined amount. The torpedo member 42 has first and second conical 113 ~
1 ends 80, 82 which, in this embodiment, extend from raised cylindrical centering portions 84, 86 of the surface of the torpedo member 42. Wpon assembly of the torpedo member 42 in the hollow outer member 40, the torpedo member 42 is restricted against axial movement by the abutment of the first conical end 80 on the conical surfaces 88 extending from the inner surface 50 of the body portion 44 of the outer member 40, and by the abutment of second conical end 82 on conical surfaces 90 of the retaining collar portion 46. The raised cylindrical portions 84, 86 of the surface of the torpedo member 42 abut on the cylindrical inner surface 50 to ensure that the torpedo member 42 is centrally located in the passage 48 to thereby form elongated filtering slits 92 having a uniform width between the outer surface 78 of the inner torpedo member 42 and the lands 56 of the outer member 40. In order to ensure that all of the melt passing through the assembly is filtered, the inner torpedo member must be located so that the cylindrical outer surface 78 (including raised portions 84, 86) extends at least from the dead ends 94 of the .
outlet channels 54 to the dead ends 96 of the inlet channels 52.
All components are made of H13 steel, although other materials having sufficient strength, durability, and suitable heat transfer characteristics may also be used.
In use, the body portion 44 of the outer member 40 is screwed into the molding machine 12 and the torpedo member is inserted into it. The retaining collar portion 46 is then screwed on and a predetermined torque is applied to ensure that the sloping portions 72 of the outlet channels 54 are in alignment with the respective remaining portions, at which time the conical ends 80, 82 of the torpedo member 42 are abutting respectively on the conical surfaces 88, 90. The filter assembly 10 is then 113~23~
1 positioned against the back plate 14 and molding begins. The pressurized melt from the lding machine 12 is directed by sloping surfaces 60 to flow smoothly into inlet channels 52. As best seen in Figs. 3 and 5, the melt cannot pass through the inlet channels 52 due to dead ends 96 and therefore it flows circumferentially around the outer surface 78 of the torpedo member 42 through the filtering slits 92 and into the adjacent outlet channels 54. The contaminants which are too large to pass through the filtering slits 92 are carried along the inlet channels 52 and accumulate adjacent the dead ends 96. The filtered melt flows smoothly from the outlet channels 54 through the outlet opening 6g into the hot runner passage 16.
The large cross sectional area of the filtering slits 92 ensures that there is a relatively low pressure drop through the filter assembly even when the inlet channels 52 become partially filled with accumulated contaminants. The total cross sectional area of the inlet channels 52 and the outlet channels 5g may be increased by increasing the diameter of the outer member 40 and the total area of the filtering slits may accor-29 dingly be increased by increasing the length of the filterassembl~. Furthermore, the inlet and outlet structure of the filter assembly provides for smooth flow of the melt through the assembly and avoids dead spots.
After an extended period of use, the accumulated con-taminants may be quickly and easily removed by unscrewing the retaining collar portion 46 of the outer member 40 and taking out the inner torpedo member 42. If a different application or type of molding material indicates that a different dimension of filtering slit is required, the inner torpedo member 42 may be replaced from stock by a torpedo member having the appropriate 1 diameter. Uniform melt temperature is maintained by the large surface area of the outer member 40 in contact with the melt.
If necessary, additional heating may be supplied by heating elements in or around the walls of the outer member 40.
The filter assembly 10 seen in Fig. 6 is similar in most respects to the embodiment described above and features common to both embodiments are described and illustrated using the same reference numerals. However, as may be seen, the inlet and outlet channels 52, 54 have been substantially increased in cross sectional area. Thus, an increase in the area of the filtering slits 92 between the inner torpedo member 42 and the outer member 40 by lengthening the filter assembly may be accommodated without increasing the pressure drop.
Fig. 7 illustrates an alternate embodiment of inner torpedo members 42. In this embodiment, the generally cylin-drical outer surface 78 is interrupted by a larger number of raised centering portions 98. When assembled, these raised centering portions 98 abut on the cylindrical inner surface 50 of the outer member 40 to ensure that the inner torpedo member 42 is properly located throughout its length. This avoids any changes in the dimensions of the filtering slits 92 due to side-ways flexing of the inner torpedo member 42 under the pressure of the melt.
Although the description of this invention has been given with respect to these particular embodiments, it is not to be construed in a limiting sense. Many variations and modifi-cations will now occur to those skilled in the art. For instance, different numbers of inlet and outlet channels could be used with satisfactory results. For a definition of the invention reference is made to the appended claims.
1~3Z~
SUPPLEMENTARY DISCLOSURE
, In addition to the subject matter described in the principal disclosure, this invention includes other embodiments showing the filtering apertures having differen-t shapes.
The filtering apertures of these further embodiments are shaped to prevent the passage of thin flakes of impurities while otherwise might pass through the elongated slits. To this end, in a further aspect the invention provides an improved injection molding filter assembly to filter pressurized melt flowing therethrough towards a gate comprising an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outle-t opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands each having an inner surface and all being located an equal distance from the central axis, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and a generally cylindrical elongated inner torpedo member having an outer surface, the inner member being centrally located and longitudinally secured in the outer member to extend at least between the first and second blind ends, whereby filtering apertures are defined between the outer surface of the inner member and the inner surfaces of the lands through which the melt flows from the inlet channels to the outlet channels, impurities too large to pass through the filtering apertures being accumu-lated at the blind ends of the inlet channels.
~L3~32~
1 The above and other objects, advantages and features of the invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings wherein:
Fig~ 8 is a partial section of an isometric view showing another embodiment of the invention;
Fig. 9 is an isometric view of an inner torpedo member according to a further embodiment of the invention; and Fig~ 10 is a partial section of an isometric view showing yet another embodiment of the invention.
Most of the features of the additional embodiments are identical to those of the principal disclosure and therefore common features are described and illustrated using the same reference numerals. In order to avoid redundancy with the principal disclosure, the common structure and function will not again be described in detail.
The embodiment of the invention shown in Figure 8 has an inner torpedo member 42 with a cylindrical outer surface 78 having no raised portions. However, the inner surface 50 of the outer member 40 has alternating ridges 100 and grooves 102 which extend laterally across the lands 56. When assembled, the ridges 100 extend to abut or substantially abut on the outer surface 78 Gf the inner member 42.
In use, the operation is substantially the same as described in the principal disclosure except that the melt must pass through the filtering apertures 92 formed by the grooves 102.
As may be seen, a munber of these apertures 92 are formed on each land rather than a single elongated slit in the firs~
described embodiment. This has the advantage of filtering flakes of impurities which might otherwise be thin enough to pass 113~
1 through the elonga~ed slits if oriented to do so. The dimensions of the grooves are normally a little smaller than the diameter of the gate, for instance, 0.040 inches wide, 0.040 inches deep, with 0.020 inch radius hottom corners, and the ridges 100 are normally thinner than the grooves 102 to provide the maximum number of grooves 102 along each land 56 to maximize capacity and minimize pressure drop.
Another variation is shown in Fig. 9 wherein the lateral ridges 100 and grooves 102 are located on the outer surface 78 of the inner torpedo member 42 and the ridges 100 abut on the smooth inner surfaces 50 of the lands S6. In neither instance would the ridges and grooves normally extend towards the ends past the dead ends 94, 96 of the channels 52, 54 in order to avoid undesirable dead spots. While the ridges 100 and grooves 102 are formed to extend laterally they may also be formed by threading the inner torpedo member 42 or tapping the outer member 40.
Fig. 10 shows still another variation which may be used for certain types of materials and is particularly useful for unusually dirty melt to maximize capacity and minimize the number of clean outs require. In this embodiment, ridges 100 and grooves 102 are formed on both the outer surface 78 of the inner torpedo member 42 and the inner surfaces 50 of the lands ; 56. The ridges 100 and grooves 102 are of substantially equal width, the inner torpedo member is longitudinally located in the outer member 40 so that the ridges of one are in alignment with the grooves of the other, and the tops or surfaces 104 of the ridges of both are of substantially equal diameter, whereby the grooves 102 of both form separate filtering apertures ~2. Once again, ridge an~ groove surfaces are not extended towards the ~"`
~13'~3~
1 ends past the dead ends 94, 9Ç to avoid the formation of dead spots where the melt will collect causing problems of deterior~
ation and on colour change.
The use of this embodiment of the invention is substantially the same as of the foregoing embodiments, except that the filtering capacity is significantly increased due to the increased number and area of filtering apertures.
Still further variations and modifications of the invention will occur to those skilled in the art. For example, different numbers and shapes of filtering apertures could be used with satisfactory results, depending upon the type of material being filtered and other conditions of the particular application of the invention.
` .
, ' .
Claims (16)
1. An improved injection molding filter assembly to filter pressurized melt flowing threrethrough comprising:
(a) an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands all being located an equal distance from the central axis along their length, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and (b) an elongated inner torpedo member centrally located in the outer member, having a generally cylindrical outer surface which is smaller in radius by a predetermined amount than the said distance of the lands from the said central axis to form a number of elongated filtering slits between the outer surface of the inner member and said lands through which the melt flows from the inlet channels to the outlet channels, the inner torpedo member being longitudinally secured to have the cylindrical outer surface extend at least between the first and second blind ends, impurities too large to pass through the filtering slits being accumulated at the blind ends of the inlet channels.
(a) an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands all being located an equal distance from the central axis along their length, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and (b) an elongated inner torpedo member centrally located in the outer member, having a generally cylindrical outer surface which is smaller in radius by a predetermined amount than the said distance of the lands from the said central axis to form a number of elongated filtering slits between the outer surface of the inner member and said lands through which the melt flows from the inlet channels to the outlet channels, the inner torpedo member being longitudinally secured to have the cylindrical outer surface extend at least between the first and second blind ends, impurities too large to pass through the filtering slits being accumulated at the blind ends of the inlet channels.
2. A filter assembly as claimed in claim 1 wherein the inner torpedo member has first and second end surfaces which abut respectively against retaining surfaces at the first and second ends of the outer member to longitudinally secure the inner member in the outer member.
3. A filter assembly as claimed in claim 2 wherein the end surfaces of the inner torpedo member are conical shaped.
4. A filter assembly as claimed in claim 2 wherein the outer member has a body portion and a retaining collar portion removably attached to the body portion, the collar portion defining the outlet opening at the second end of the outer member and having the retaining surfaces which abut against the second end surface of the inner torpedo member, whereby the inner torpedo member may be easily removed for cleaning by removing the retaining collar portion of the outer member.
5. A filter assemply as claimed in claim 1, 2 or 3 wherein the outer surface of the inner torpedo member has longitudinally spaced raised portions which abut on the lands between the channels to securely centrally locate the inner torpedo member in the outer member.
CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE
CLAIMS SUPPORTED BY SUPPLEMENTARY DISCLOSURE
6. An improved injection molding filter assembly to filter pressurized melt flowing therethrough towards a gate comprising:
(a) an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands each having an inner surface and all being located an equal distance from the central axis, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and (b) a generally cylindrical elongated inner torpedo member having an outer surface, the inner member being centrally located and longitudinally secured in the outer member to extend at least between the first and second blind ends, whereby filtering apertures are defined between the outer surface of the inner member and the inner surfaces of the lands through which the melt flows from the inlet channels to the outlet channels, impurities too large to pass through the filtering apertures being accumulated at the blind ends of the inlet channels.
(a) an elongated hollow outer member having a central longitudinal axis, a first end and a second end, the first end having an inlet opening and the second end having an outlet opening, the outer member having a fluted inner surface defining an even number of inwardly opening longitudinally extending channels with narrow elongated lands therebetween, the lands each having an inner surface and all being located an equal distance from the central axis, alternate ones of the channels extending from the inlet opening to first blind ends towards the second end of the outer member, the other intervening channels extending from the outlet opening to second blind ends towards the first end of the outer member, and (b) a generally cylindrical elongated inner torpedo member having an outer surface, the inner member being centrally located and longitudinally secured in the outer member to extend at least between the first and second blind ends, whereby filtering apertures are defined between the outer surface of the inner member and the inner surfaces of the lands through which the melt flows from the inlet channels to the outlet channels, impurities too large to pass through the filtering apertures being accumulated at the blind ends of the inlet channels.
7 A filter assembly as claimed in claim 6 wherein alternating ridges and grooves extend laterally across the inner surfaces of the lands, the ridges extending substantially to the outer surface of the inner member, whereby each of the grooves forms a separate filtering aperture to effectively reduce the size of impurities which will pass through the filter assembly.
8. A filter assembly as claimed in claim 7 wherein the ridges and grooves are formed by tapping at least a portion of the inner surfaces of the lands.
9. A filter assembly as claimed in claim 6 wherein alternating ridges and grooves extend around the outer surface of the inner member, the ridges extending substantially to the inner surface of the outer member, whereby the grooves form a plurality of separate filtering apertures to effectively reduce the size of impurities which will pass through the filter assembly.
10. A filter assembly as claimed in claim 9 wherein the ridges and grooves are threaded onto at least a portion of the outer surface of the inner member.
11. A filter assembly as claimed in claim 7 or 9 wherein the width and depth of the grooves are less than the diameter of the gate.
12. A filter assembly as claimed in claim 6 wherein alternating ridges and grooves extend laterally across the inner surfaces of the lands and alternating ridges and grooves extend around the outer surface of the inner member, the surfaces of the ridges on the lands and the surfaces of the ridges on the inner member being of substantially equal diameter, the ridges on one being in alignment with and substantially equal in width to the grooves on the other whereby the grooves on both the lands and the inner member form separate filtering apertures.
13. A filter assembly as claimed in claim 12 wherein the width and depth of the grooves are less than the diameter of the gate.
14. A filter assembly as claimed in claim 6 wherein the inner torpedo member has first and second end surfaces which abut respectively against retaining surfaces at the first and second ends of the outer member to longitudinally secure the inner member in the outer member.
15. A filter assembly as claimed in claim 14 wherein the end surfaces of the inner torpedo member are conical shaped.
16. A filter assembly as claimed in claim 14 wherein the outer member has a body portion and a retaining collar portion removably attached to the body portion, the collar portion defining the outlet opening at the second end of the outer member and having the retaining surfaces which abut against the second end surface of the inner torpedo member, whereby the inner torpedo member may be easily removed for cleaning by removing the retaining collar portion of the outer member.
Priority Applications (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA332,292A CA1132321A (en) | 1979-07-20 | 1979-07-20 | Injection molding filter assembly |
| US06/060,827 US4256584A (en) | 1979-07-20 | 1979-07-25 | Injection molding filter assembly |
| US06/162,809 US4280908A (en) | 1979-07-20 | 1980-06-24 | Injection molding filter assembly |
| GB8021484A GB2054399B (en) | 1979-07-20 | 1980-07-01 | Filter assembly |
| DE19803025390 DE3025390A1 (en) | 1979-07-20 | 1980-07-04 | FILTER DEVICE FOR INJECTION MOLDING MACHINES |
| JP55098205A JPS5947978B2 (en) | 1979-07-20 | 1980-07-19 | injection molded filter assembly |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA332,292A CA1132321A (en) | 1979-07-20 | 1979-07-20 | Injection molding filter assembly |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1132321A true CA1132321A (en) | 1982-09-28 |
Family
ID=4114753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA332,292A Expired CA1132321A (en) | 1979-07-20 | 1979-07-20 | Injection molding filter assembly |
Country Status (5)
| Country | Link |
|---|---|
| US (2) | US4256584A (en) |
| JP (1) | JPS5947978B2 (en) |
| CA (1) | CA1132321A (en) |
| DE (1) | DE3025390A1 (en) |
| GB (1) | GB2054399B (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3465020D1 (en) * | 1984-01-28 | 1987-09-03 | Odenwalder Kunststoffwerke | Mud filter for tenacious thermoplastic substances |
| IT1178951B (en) * | 1984-05-31 | 1987-09-16 | Mario Beolchi | FILTER FOR INJECTOR NOZZLES PARTICULARLY FOR INJECTION MOLDING EQUIPMENT OF PLASTIC MATERIALS AND INJECTOR NOZZLE EQUIPPED WITH SUCH FILTER |
| JPS63106076U (en) * | 1986-12-27 | 1988-07-08 | ||
| US4965028A (en) * | 1987-09-04 | 1990-10-23 | Galic/Maus Ventures | Method of injection molding thermoplastic through multiple gates |
| JPS6448882U (en) * | 1987-09-21 | 1989-03-27 | ||
| US4906360A (en) * | 1989-02-28 | 1990-03-06 | Panos Trakas | Multi-stage injection molding filter |
| JPH0650173Y2 (en) * | 1989-04-28 | 1994-12-21 | 豊田合成株式会社 | Injection molding machine |
| JPH03112876U (en) * | 1990-02-28 | 1991-11-19 | ||
| JPH04112021A (en) * | 1990-08-31 | 1992-04-14 | Mitsubishi Materials Corp | Mold set for molding resin |
| US5539857A (en) * | 1994-01-24 | 1996-07-23 | Caco Pacific Corporation | Heater block for injection molding with removable heat conductive member in groove in heater block |
| US6099292A (en) * | 1997-10-22 | 2000-08-08 | Caco Pacific Corporation | Heater block with unitized removable heat conductive member |
| MXPA02008921A (en) | 2000-03-14 | 2004-10-15 | James Hardie Res Pty Ltd | Fiber cement building materials with low density additives. |
| PL201390B1 (en) * | 2001-03-02 | 2009-04-30 | James Hardie Int Finance Bv | A method and apparatus for forming a laminated sheet material by spattering |
| US20030164119A1 (en) * | 2002-03-04 | 2003-09-04 | Basil Naji | Additive for dewaterable slurry and slurry incorporating same |
| JP4701542B2 (en) * | 2001-05-31 | 2011-06-15 | 澁谷工業株式会社 | Filling apparatus and filling method thereof |
| US7156651B2 (en) * | 2001-07-06 | 2007-01-02 | Husky Injection Molding Systems Ltd. | Apparatus for injection molding articles |
| US20030008034A1 (en) * | 2001-07-06 | 2003-01-09 | Husky Injection Molding, Ltd. | Method and apparatus for injection molding articles |
| MXPA05003691A (en) | 2002-10-07 | 2005-11-17 | James Hardie Int Finance Bv | Durable medium-density fibre cement composite. |
| US7998571B2 (en) | 2004-07-09 | 2011-08-16 | James Hardie Technology Limited | Composite cement article incorporating a powder coating and methods of making same |
| US20070151920A1 (en) * | 2005-12-06 | 2007-07-05 | Kay Ronald J | System and method of micromolded filtration microstructure and devices |
| NZ571874A (en) | 2006-04-12 | 2010-11-26 | Hardie James Technology Ltd | A surface sealed reinforced building element |
| US8209927B2 (en) * | 2007-12-20 | 2012-07-03 | James Hardie Technology Limited | Structural fiber cement building materials |
| WO2015112462A1 (en) * | 2014-01-24 | 2015-07-30 | Husky Injection Molding Systems Ltd. | A melt conditioner |
| IT202100000767A1 (en) * | 2021-01-18 | 2022-07-18 | Df3 S R L | FILTERING SYSTEM OF ANY EXTRUSION LINE AND RELATIVE METHOD OF USE |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1335899A (en) * | 1920-01-12 | 1920-04-06 | Kahlenberg Bros Co | Fluid-filter |
| US1802423A (en) * | 1928-03-01 | 1931-04-28 | Hemmingsen Torkild Valdemar | Filter for fine filtering of fluids especially fuel oils |
| US3789990A (en) * | 1970-11-15 | 1974-02-05 | M Drori | Strainer for liquid pipe lines |
| US3767056A (en) * | 1971-08-06 | 1973-10-23 | A 1 Eng | Injection molding filter |
| US3825123A (en) * | 1972-08-10 | 1974-07-23 | A 1 Eng | Injection molding filter |
| JPS5098557A (en) * | 1973-12-28 | 1975-08-05 | ||
| US3952927A (en) * | 1974-04-26 | 1976-04-27 | Standard Oil Company | Injection nozzle having guides for nozzle rod |
| US4069003A (en) * | 1975-04-21 | 1978-01-17 | Dinamode Corporation | Injection molding apparatus |
| CA1072281A (en) * | 1976-03-24 | 1980-02-26 | Jobst U. Gellert | Injection molding filter assembly |
| US4097216A (en) * | 1977-03-11 | 1978-06-27 | Magna International Inc. | Filter for liquids |
-
1979
- 1979-07-20 CA CA332,292A patent/CA1132321A/en not_active Expired
- 1979-07-25 US US06/060,827 patent/US4256584A/en not_active Expired - Lifetime
-
1980
- 1980-06-24 US US06/162,809 patent/US4280908A/en not_active Expired - Lifetime
- 1980-07-01 GB GB8021484A patent/GB2054399B/en not_active Expired
- 1980-07-04 DE DE19803025390 patent/DE3025390A1/en active Granted
- 1980-07-19 JP JP55098205A patent/JPS5947978B2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5617234A (en) | 1981-02-19 |
| GB2054399A (en) | 1981-02-18 |
| DE3025390C2 (en) | 1987-04-30 |
| US4280908A (en) | 1981-07-28 |
| JPS5947978B2 (en) | 1984-11-22 |
| GB2054399B (en) | 1983-11-09 |
| DE3025390A1 (en) | 1981-02-19 |
| US4256584A (en) | 1981-03-17 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |