US3601355A

US3601355A - Apparatus for molding articles

Info

Publication number: US3601355A
Application number: US807620A
Authority: US
Inventors: Paul H Fleck
Original assignee: Urethane Fabricators Inc
Current assignee: Urethane Fabricators Inc
Priority date: 1969-03-17
Filing date: 1969-03-17
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24

Abstract

Apparatus for molding articles having a base, a pair of side plates hinged thereto for movement to and from a lowered position and a raised position in opposed relation, said base and side plates forming a mold cavity when said side plates are raised, and means for retaining said side plates in raised position to provide said cavity. In one form, an end plate may also be provided hinged to said base for movement to and from a lowered and a raised position. When said side and end plates are in raised position, they may be interlocked in the latter position to maintain said cavity.

Description

[72] Inventor United States Patent Paul II. Fleck Melrose Park, Pa.

[21 Appl. No. 807,620

[22] Filed Mar. 17, 1969 [45] Patented Aug. 24,1971

[7 3 Assignee Urethane Fabricators, Inc.

Camden, NJ.

Division ofSer. No. 760,414, Sept. 18, 19633.

[54] APPARATUS FOR MOLDING ARTICLES [56] References Cited UNITED STATES PATENTS 457,542 8/1891 Wells 249/172 2,576,153 11/1951 Tannenberg 249/91 FOREIGN PATENTS 528,838 6/1955 ltaly 249/148 Primary Examiner-J. Spencer Overholser Assistant Examiner-Lucius R. Frye Auomey-Jacob Trachtman ABSTRACT: Apparatus for molding articles having a base, a pair of side plates hinged thereto for movement to and from a lowered position and a raised position in opposed relation, said base and side plates forming a mold cavity when said side plates are raised, and means for retaining said side plates in raised position to provide said cavity. In one form, an end plate may also be provided hinged to said base for movement to and from a lowered and a raised position. When said side and end plates are in raised position, they may be interlocked in the latter position to maintain said cavity.

PATENTED AUB24 I97! SHEET 1 BF 5 uws/vron? PAUL a a [CK PATENTED AUG24 um SHEET 3 BF 5 INVENTOR PAUL H. FLECK PATENTED AUG24 l97| SHEEI k (If 5 INVENTOR PAUL H. FLECK JMW PATENTED AUG24 l9?! SHEET 5 BF 5 INVENTOR PAUL H. FLECK I ATTORNEY APPARATUS FOR MOLDING ARTICLES No. 760,414, filed Sept. 18, 1968, for Molded Simulated Wooden Articles and Method For Producing The Same.

This invention relates to apparatus for molding articles which simulate a natural product such as, for example, a wooden beam or the like, and it also relates to the process of making such article.

Wooden beams, wall panels, and the like are becoming increasingly used as decorative features in the home, the office, the factory showroom and other such areas. However, one of the factors mitigating against their wider use is the high cost of wood, especially wood containing a distinctive texture consisting of certain desirable graining, knot holes, distress marks, etc. Although synthetic products made of pressed board or plastics have heretofore been used to simulate the appearance of wood, it has not, heretofore, been possible to provide the appearance of graining, knot holes, distress marks, and the like, in a manner sufficiently similar to the actual wood to be a satisfactory substitute for such wood.

It is an object of the presentinvention to overcome the above difficulties by providing improved molding apparatus for molding articles of synthetic'plastic material and which have, in every way, the'appearance of grained, knot holed or otherwise distinctively textured natural products such as wood; I

Another object of the present invention is to provide improved molding apparatus as aforesaid which is simple in structure, which is relatively inexpensive and which, because its use requires relatively little skill, has a high degree of commercial feasibility.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following description when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a fragmentary top perspective view of a molded, simulated wooden beam embodying the present invention.

FIG. 2 is a perspective view, partly broken away, of a room provided with a beamed structure embodying the present invention.

FIGS. 3 through 17 are either perspective or cross-sectional views showing the various steps in forming the article of FIG. 1.

FIG. 18 illustrates an alternative type of mold box.

The simulated article may be formed from any of a variety of therm osetting polymeric materials, especially of the foam type. Among such polymers are urethane foam, phenolic foam, urea formaldehyde, epoxy foam, polystyrene foam, polyether foam, etc., which are utilized either by themselves or to form a reaction product with fluorinated hydrocarbons. The preferred material is a polyurethane foam, as illustrated by the following examples:

The preferred material for making the simulated article is a polyurethane foam. A preferred type of such polyurethane foam is prepared from a commercially available product called lsonate System CPR 336" produced by the Upjohn Company, Torrence, California. It is a fluorocarbon-blown, rigid polyether urethane foam. The following example illustrates such composition:

Example 1 The two components are mixed for seconds at a mixing speed of 7,000 rpm.

The resulting mixture has a cure time of about 8 minutes at 145 F., at the end of which time a polyurethane foam is produced.

Referring now in greater detail to the various figures of the drawings, there is shownin FIG. 1 a portion of a molded beam,

7 generally designated 10, embodying the present invention.

Two polyurethane components, A and B (Isonate System The beam 10 is shown as being rectangular in shape and as having an undercut recess 12. It is also provided with graining l4 and knot holes 16. It is, however, to be understood that any other wood texture and any other shape or size is equally within the scope of the invention.

FIG. 2 illustrates how a beam, such as beam 10 of FIG. 1, is utilized as a decorative feature in a room. The room is indicated generally at 18 and includes walls 20 and a ceiling 22. The beam 24 (similar to beam 10) is provided with a longitudinal plug 26 frictionally or otherwise retained in the groove 28 (similar to groove 12 in FIG. 1). This plug 26 is provided with nails 30, which may, optionally, be set in place prior to insertion of the plug 26 in the groove 28 so that the heads thereof bear against the rear surface of the plug. The nails 30 serve to hold the beam against the ceiling. Instead of nails, glue or any other securing means may be used as desired. Vertical beams 32, similar to the beam 24, may also be provided, if desired. These may be securedin any desired manner both to the horizontal beam 24 and to the walls 20, as for example, by glue 34. I

The process of making the beam 10 is illustrated in FIGS. 3

to 18 inclusive. FIG. 3 shows a wooden master 36 of the exact size, shape -and texture desired in the final molded article. The master 36 is proved with an undercut recess 38 and a plurality 5 of hanger bolts 40 which are screwed into the bottom edges of the walls bounding the recess 38. The master 36 is set in place in a three-sided aluminum mold box 42 which includes a floor plate 44 mounted on a I wooden base 45, side panels 46 hingedly connected to the floor plate 44, and an end plate 48 which is also hingedly connected to the floor plate 44 in proximity to the side 'panels 46 and which has side wings 48a that embrace and abut the side panels 46 when the side panels 46 and the end plate 48 are in their raised positions. When the side panels 46 are raised, they cooperate with the floor plate 44 to provide a mold cavity, as will appear more clearly hereinafter. When all of the

plates

46 and 48 are raised, the end plate 48 engages the proximate ends of the side panels 46 and it can be releasably secured to the side panels 46 by'pins 49 to insure maintaining the aforesaid mold cavity. The floor plate 44 is provided with drilled apertures 50 which are adapted to receive the bolts 40. Wing nuts 52 (shown in FIGS. 4 and 5) are positioned in recesses 53 in the base 45 and serve to hold the bolts 40 in position and securely clamp the master in place. The side plates 46 and end plate 48 are then moved into the closed or operative position shown in FIGS. 4 and 5. It is to be noted that, in the closed position, the side plates 46 are inwardly inclined toward each other in an upward direction (See FIGS. 4, 5, 8 to 13', and 18). This is important because it permits the molded material to expand when heated and when it, itself, serves as a mold for the final product.

After the mold is in position, as in FIG. 4, the mold-forming substance which, in this instance, is silicone rubber (General Electric grade RTV60), is poured into the mold box. The silicone is worked into the surfaces with putty knives so that any air bubbles present will be broken up and no holes will, there fore, be present in the surfaces of the completed mold. The mold is then left to cure at room temperature for a period of from about 24 to 48 hours, after which it is placed in a heated oven for 2 hours at about F. to complete the cure. The resultant mold 54 is an exact reverse duplicate of the master 36 not only in size and shape but also as regards every indentation, knot hole and grain structure' After the mold has cooled, both it and the master.36, while still together, are removed from the mold box 42 (as shown in FIG. 6). The master 36 is then removed and the mold 54 is ready for use.

Although silicone rubber is preferred as the material for the mold 54, other substances can be used, such as, for example, latex rubber, etc. The silicone rubber is preferred, however, because it is easier to apply and is longer lasting, and also because it provides the most satisfactorygrain structure.

In the next step (as shown in FIG. 7), the mold 54 is reversed, so that the cavity is uppermost, and it is then placed in the mold box 42. The side and end plates of the mold box are then closed (as in FIG. 8), and the internal surfaces of the mold 54 are sprayed with an appropriate release agent.

It is preferred to use a release agent since most polyurethane foams contain some amino acid which causes a reaction between the silicone and the polyurethane. This reaction results in an adhesive layer between the mold and the polyurethane which might damage the product when the mold is released. Furthermore, although there are some special silicone rubbers and also urethane foams that are not made with any amino acids, and which, therefore, do not require a release agent for this reason, eventually an adhesive reaction does set in. This adhesive reaction causes pulling up of the surface skin of the urethane, resulting in damage when the mold is released.

Various types of release agents may be used such as waxlike olefins or silica gel suspended in methylene chloride or acetone, or polyethylene, polypropylene, polyisobutylene, etc. suspended in suitable liquid vehicles. In all cases, if a liquid solvent etc., carrier is used for the release agent, it is preferred to have such liquid vaporize at the molding temperature so as to leave only the release agent. It has been found that a very suitable release agent is a 12 percent solution of waxlike olefins in methylene chloride.

The spraying of the release agent is shown in FIG. 9, any or- I dinary spray head, such as indicated at 56, being used. If desired, the release agent may be applied by other means such as brushing, dipping, etc., depending on the particular agent used and on the particular treating apparatus.

The liquid polyurethane foam is then deposited in the mold cavity by a spray or pour head, or the like, 58, as shown in FIG. 10. It is to be noted that the spray or pour head contains a plurality of nozzles extending in different radial directions so that the foam is evenly distributed on all surfaces of the mold, thereby preventing fold over of foam caused by rise of the foam from the lower surface only.

Thereafter, as shown in FIG. 11, an aluminum insert 60 is applied, as indicated in FIG. 11, and is held in position by pins 62 (see FIG. 12) inserted through corresponding apertures in the end plate 48 of the mold box and in an end plate 63 (see FIG. 11) on the insert 60. The insert is used to form a center cavity in the final product.

The mold box and its contents are then placed in an oven (not shown) where it remains at the particular curing temperature and for the particular time required to cure the particular material. In this instance, the temperature is maintained at 145 F. for a period of about minutes.

The inclined sides 46 also serve an important function in this step because they result in providing sharp details of all the features and texture of the mold on the molded article.

After the curing has been completed, the insert 60 is then removed (as shown in FIG. 13), and the mold box is opened (as in FIG. 14). The molded article 64 may be removed either mechanically or by hand, as, for example, by means of a wedge 66 or the like (as in FIG. 15), and the excess or waste is cut away by a knife or saw 68 (as in FIG. 16), The article is then placed on a moving support conveyor 70 (as in FIG. 17) and painted with the desired wood-colored paint, as by a spray gun 72 or by any other desired means, to simulate the original color of the master.

An alternative type of mold box is illustrated in FIG. 18. This mold box, generally designated 80, is similar to the mold box 42 in having the same wooden base 82, floor plate 84, and hinged sideplates 86. However, the top flanges 88 on each sideplate are each provided with an upstanding lug 90 which pivotally supports a fork-type lever 92, the levers 92 being so positioned as to extend in opposite directions over the mold cavity between the sideplate 86 when the sideplates are raised. The lever 92 is pivotally connected to a rod 94 having a handle 96 at one end and to the other end of which is pivotally connected a bearing plate 98.

The operation of the apparatus of FIG. 18 is obvious from the drawings. The bearing plates 98 apply pressure to the insert 100, and this pressure can be predetermined by the setting of the levers. This type of apparatus provides a more positive pressure than that illustrated in FIGS. 3 to 17.

Although not specifically illustrated as such in the drawings, this process is adapted to be conducted in a continuous manner on a conveyor system wherein there are a series of mold boxes on a conveyor belt, and a series of stations, one station for each operation indicated in FIGS. 3 to 17 (or alternatively including the operation of clamping and unclamping the pressure plates if the mold box of FIG. 18 is used). This type of process would provide for timed, intermittent steps or pauses to permit each operation to take place. This would include the necessary pause for permitting curing to take place in the oven.

Obviously, many modifications of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

lclaim:

1. Molding apparatus for molding articles with an insert comprising a base, a pair of opposed side panels hingedly carried by said base and each movable from a lowered, inactive position to a raised, upright, active position to form with said base an open-topped mold cavity, an end plate also hingedly carried by said base in proximity to said side panels and also movable from a lowered, inactive position to a raised, upright, active position against the ends of said side panels when said side panels are in their said raised positions, and locking means positioned below the open top of said mold cavity for releasably locking said side panels and said end plate to each other in their respective raised positions whereby to insure maintaining said mold cavity, said base having attachment means thereon for releasably and selectively securing a mold element within said mold cavity, said apparatus being characterized in that each side panel has a flange at its upper end when it is in its said raised position, and characterized further in that each said flange has associated therewith means for applying downward pressure to said insert.

2. Molding apparatus according to claim 1 characterized in that said end plate and said side panels are so mounted on said base that when they are in their respective said lowered positions. they are in substantially coplanar relation.

3. Molding apparatus according to claim 1 characterized in that when said side panels are in their respective said raised positions, they are inclined toward each other in an upward direction.

4. Molding apparatus according to claim 1 wherein said base comprises a wooden base having a floor plate thereon, and wherein said panels and said end plate are hingedly connected to said floor plate.

5. Molding apparatus according to claim 1 wherein said pressure applying means comprises a separate lever pivotally carried by each said flange, and characterized further in that each said lever has pivotally coupled thereto a bearing plate adapted to engage said insert and to apply pressure thereto when said levers are lowered.

6. Molding apparatus according to claim 1 characterized in that each of said flanges supports a pivotally mounted lever, and a separate bearing plate associated with each said lever in a position to engage said insert for applying pressure thereon when its lever is lowered.

7. Molding apparatus according to claim 6 wherein each of said flanges has a lug thereon, and wherein said levers are pivotally connected to the respective said lugs.

plate has side wings adapted to embrace and abut against said side panels, and characterized by said locking means being constructed and arranged to cooperate with said side wings and with said side panels for maintaining said side panels and said end plate in raised, cooperative relation.

Claims

2. Molding apparatus according to claim 1 characterized in that said end plate and said side panels are so mounted on said base that when they are in their respective said lowered positions, they are in substantially coplanar relation.

8. Molding apparatus according to claim 6 wherein each of said flanges has a lug thereon, said levers being respectively pivotally connected to separate ones of said lugs and extending over said molding cavity when said panels are in their said raised positions.

9. Molding apparatus according to claim 1 wherein said end plate has side wings adapted to embrace and abut against said side panels, and characterized by said locking means being constructed and arranged to cooperate with said side wings and with said side panels for maintaining said side panels and said end plate in raised, cooperative relation.