US2577350A - Method of forming die cast products - Google Patents

Description

Dec. 4, 1951 L. H. MORIN 2,577,350

METHOD OF FORMING DIE CAST PRODUCTS Original Filed Dec. 28, 1943 5 Sheets-Sheet l 1 H H H I 1 H i |j| (D INVENTOR. 5 42 Lou/sHMole/N Dec. 4, 1951 L. H. MORIN 2,577,350

METHOD OF FORMING DIE CAST PRODUCTS Original Filed Dec. 28, 1945 3 Sheets-Sheet 2 IN V EN TOR.

Lou/5 H. Mae/N Dec. 4-, 1951 MORIN 2,577,350

METHOD OF FORMING DIE CAST PRODUCTS Original Filed Dec. 28, 1943 5 Sheets-Sheet 5 70 v, 63 {-70 71 I -61 61 I 75 61 "M n M 60 9 79 6O 79 1 INVENTOR. Lou/5 H. Moe/1v Patented Dec. 4, 1951 UNITED STATES PATENT OFFICE Original applications December 28, 1943, Serial Nos. 515,196, 515,197, and 515,198. Divided and this application June 23, 1945, Serial No. 601,154

12 Claims.

This invention relates to the production of various articles of manufacture such, for example, as hinges, buckles, as well as swivel jointed bodies. More particularly, the invention deals with a method of producing articles of manufacture of the type and kind defined, wherein each article is composed of two die cast parts, one part being cast with a socket or bearing portion and the other part cast with a pin rod or pintle portion formed directly in the socket or bearing portion of the first part in providing relative swinging or rotatable movement of the parts one with respect to the other. The novel features of the invention will be best understood from the following description, when taken together with the accompanying drawing, in which certain embodiments of the invention are disclosed and, in which, the separate parts are designated by suitable reference characters in each of the views and, in which:

Fig. 1 is a diagrammatic face view of one of the dies employed in forming a pair of hinge leaves showing one method of forming and intercasting said leaves.

Fig. 2 is a section on the broken line 2-2 of Fig. 1.

Fig. 3 is a perspective view of a hinge detached by a trimming operation.

Fig. 4 is a view similar to Fig. 1 showing another adaptation of the invention.

Fig. 5 is a diagrammatic face view of one of the dies which I employ in producing another article of manufacture such, for example, as a buckle.

Fig. 6 is a section on the line 66 of Fig. 5.

Fig. '7 is a perspective view of a complete buckle illustrating a use thereof with parts of a belt in dot and dash lines.

Fig. 8 is a diagrammatic face view of a pair of dies employed to form swivel coupled bodies.

Fig. 9 is a section on the broken line 9-9 of Fig. 8; and,

Fig. 10 is a detailed view of an article made from the dies shown in Fig. 8 with part of the construction broken away and in section.

This application is a division of my prior applications Serial Numbers 515,196 now Patent No. 2,569,862; 515,197 now abandoned and 515,198 now abandoned filed December 21, 943.

In constructing hinges, buckles and swivelled bodies of the type herein illustrated, it is usually customary to provide independent pins, rods 01 shaft portions for arrangement in the bearings of parts of these articles to couple the articles together. It is the purpose of my invention to materially simplify and economize on the production of articles of manufacture of this kind by forming the pintles or pins or what may be termed pivot portions as an integral portion of one of the parts of the article and to form this pintle or pin directly in the socket or apertures of the bearing portion or portions of the other part in permanently uniting said parts. In some instances, for example, in forming hinges, my improved method also eliminates exposure of pintle or pin ends and formation of heads thereon.

In Figs. 1 and 2 are shown at If] and I I the two die parts employed for producing the dual die cast body l2 in the impression chamber or cavity [3 formed on the parting line of the die parts, as will clearly appear from a consideration of Fig. 2. The upper part of the cavity 13, as seen in the drawing, is adapted to form one leaf part 14, which comprises a rectangular plate having spaced countersunk screw apertures I5 therein. At one edge of the plate are spaced pintle bearings I6 disposed inwardly of side edges of the leaf l4. On the completed hinge the bearings 16 are adapted to be arranged in the spaced recesses ll formed between the pintle bearings l8 of the leaf I9.

The leaf I9 is also in the form of a rectangular plate having the pintle bearings l8 at one edge thereof. Countersunk apertures 20 are also formed in the leaf 19 to receive the screws or other fasteners. In forming the leaves l4, 19, these leaves are simultaneously cast in the cavity 13 by injection of heated casting material from a discharge nozzle 2i through a gate passage 22 into the cavity. In the casting operation, the plate portions of the leaves I l, 19 are joined by connecting webs 23 which are severed in the trimming operation. This separates the two leaf parts which are cast as a unit but, at the same time. forms pairs of leaves l4, 19 that are permanently united and pivotally coupled by reason of the integral pintle pin portions 24 on the leaf [9 being cast in the apertures 25 of the bearings 16 or in the bushings 26 arranged in said apertures.

The unit casting I2 is formed on a core pin 21 supported in the upper portion of the dies and, upon which, the bushings 26, as inserts, are arranged. Thus after the cast unit I2 is formed, the dies are separated and the cast unit is left suspended on the core 27. This core is then moved downwardly to position the leaf part H of the first cast unit in an impression 28 at the lower portion of the dies, after which the dies are partially closed, the core pin 2! stripped 3 from the first casting, then returned to its original position and other inserts 26 arranged on the core pin and a second cast unit formed. In this last operation, the pintle pin portions 24 are cast within the bearings I6.

It will appear from a consideration of Fig. 2 of the drawing that the die II has pin portions 29 which extend across the cavities and enter recesses 33 in the die in forming the countersunk apertures I5, 20. The die II will also have at least one pin 3| in the cavity 28 to engage at least one of the pre-formed countersunk apertures of the leaf [4 to retain said leaf against displacement when the dies are in the partially closed position and in the operation of stripping the core pin, as above described.

In Fig. 4 of the drawing, I have shown another method of forming hinges of the kind under consideration which consists in forming one leaf 32at one side of a pair of dies 33 and the other leaf 34 at the other side thereof, the leaves being in spaced relationship to each other and joined through a gate 35, so that these leaves are simultaneously cast in the injection of heated casting material from a nozzle 36.

The leaf 32 has at one side edge thereof pintle bearings 31, similar in all respects to the bearings l5; whereas the leaf 34 has at one side thereof spaced bearings 38 similar to the bearings l8. Between the bearings 38 are recesses 39 for receiving the bearings 31 and are, thus, similar in this respect to the recesses 11. In other words, while the brief description of Figs. 1 and 2 has been applied to Fig. 3, it will be understood that the resulting hinge formed by the method shown in Fig. 4 will be the same as the hinge shown in Fig. 3. From this standpoint, further details of construction of the leaves 32, 34 will be omitted.

In Fig. 4, a vertical core pin 40 is employed and this core pin, in additionto extending through the bearings 31, also extends to and supports part of the gate 35, as indicated at 4|. The purpose of this is to avoid any tendency of severing the two leaves 32, 34 in shifting them, by the core pin 40, from the cast position to the lowered position where theleaf 32 enters the impression forming the leaf 34. i

After stripping the core pin 49 from the cast unit comprising the two leaves 32, 34, with the dies in a partially closed position, the core is returned to its normal position and the next successive cast unit is formed and, in this operation, the pintle portions 132 which join the bearings 38 will be formed within the bearings 31, thus pivotally and hingedly uniting the pre-cast leaf 32 with the cast leaf 34, the same as in uniting the leaf 4 with the leaf l9.

From the foregoing, it will be understood that, in both methods. of procedure, a pair of hinge leaves are formed in each casting operation and one leaf is united with its pre-cast companion leaf. In both cases, in the initial casting operation or when thefirst of a series of'leaf units are formed, a suitable plug, preferably patterned along the lines of the leaves I4, 32 will be ar- E ranged between the dies and, by making these of separate parts split along the line of the pintle, they may be removed and thereafter the operation will be continuous. The assembled hinges may be cast in units of predetermined length or they may be trimmed shortly after the cast as semblage to form the independent unit hinges comprising the leaves i4, l3, or the butts 32, 34.

In both forms, of construction, it will be a'pparent thatthe dieswill have suitable portions,

4 as at 43, fitting in the recesses ll, 39 and around the bearings 6, 31.

In referring to the use of heated casting materials, it will be understood that the hinge leaf parts may be formed from suitable metals or metal alloys or from different plastic materials. When metals are used and when it is desired to employ the bushings, these bushings may be composed of hard fibrous material or suitable bearing metals and plastics. Either harder plastics, metals or fibrous materials can be employed.

It will, of course, be apparent that the shape orcontour of the attaching plates of the leaves maybe characterized in any desired manner. Further, the combination of interengaging bearings may be modified and, in fact, the general structure of the pintle or pivot portion of the leaves may be made to suit the type of hinge employed in the hinge coupling desired between two members.

V In all instances, however, the last cast portion in producing the assembled unit will be the internal bearing portion er the coupling in order to benefit by the shrinkage of this east portion in producing the resulting free and yet firm bearing 'action'b'etween the relatively movable members. In the present illustrations, the inner or last cast portion is the pintles 24, '42. It will 'be understood that any means may be provided for supporting the bushings in proper position as ins'erts on the core pins. Slight frictional engagement with the pins would be 'sufiicient.

In Figs. 5, '6 and 7 is shown another adaptation of my invention.

"In Fig. 6 of the drawing are shown two substantially similar die parts 44, each having on the parting line or adjacent abutting surfaces 45 thereof impressions of the general contour seen in the face view of one of these dies, as illustrated in Fig. 5. The impression or cavity is divided into a hasp part 46 and a buckle part 41 to form in a single cast unit a hasp 48 and a buckle body or ring 45. These parts are vjoined by a common gate 50, into which heated casting material isinjected from'a suitable nozzle 5].

The dies 44 also have an impression or cavity 52 for'receiving a portio of the hasp E8 of a pre-cast unit, when the latter has been moved into the lowered position through the medium of a corepin 53 which extends through the looped or ringed end 5*! of the hasp and also into part of the gate '53 adjacent the ring body 49. In a simple form 'of the invention, the core 53 will form the opening or aperture of the ring 54. However, in the present illustration, a bushing 55 is arranged on the core pin 53 so as to bush the aperture or opening in the ring end 55 of the hasp. When the hasp is composed of metal,

the bushing may be of a harder or suitable "bearing metal or of fibrous material. Whereas, if the hasp is composed of a plastic die cast material, the bushing may be of metal, fiber or another plastic material having suitable bearing properties. V

The ring body 49 of the buckle in the construction shown, comprises a loop having a straight cross-head or bearing portion 56 provided at opposite sides 'of the ring portion 54 of the hasp with annular collars 57 to position the ha'sp'centrally of the cross-head 56. It will appear from a consideration of Fig. "5 of the drawj'ingithat the dies4'4 are cut out, as seen at 58, to disengage from the gate portion 50 when a precast unit is in its lowered osition. When the nit s still: urtherr emoved, r mt e di th ha n f o e unitand he-1oon odyoi=the diae ni hi h he asp. uni s tta hed by agate may be severedby atr-imming operation d hus, c mple bu l w l be orm dw the hasp 48 as an integralpar-tof the ring body 49 and free to swing or rotate thereon,

It will be understood that the resulting buckle product is formediron the hasp, of; one unit casting and the ring body of-the next successive c st na y p o c the uc le n his ner, the pintle portion 59= of, the cross head 5 6 and between the annular beads; 5 Will shrinkaway from the bushing- 55 suiiiciently to v provide a free but yet snugmounting of thehasp on the pintle 59. In the operation of forming the suce cessive castings, it will be understood that, the core 53 is stripped from a cast unitwhenin its lowered position and when the dies are in the partially closed position. When the core 53. is returned to normal position, the dies are again closed and the next successive cast unit is formed.

In the accompanying drawing a very simple and more or less conventional type of buckle has been shown for the. purpose of illustrating; one adaptation and use of the invention. It will be apparent, however, that buckles or similar articles of manufacture employing two relatively movable or swingable par-ts can. be produced in accordance with the method here defined. With buckles as illustrated, an ordinary belt may be readily and. practically used in connection therewith, as indicated at 69 in dot and dash lines in Fig. '7 of the drawing,

Figs. 8, 9.and.10 show a further adaptation of. my invention and, in Fig. 10, of the drawing is shown an. article of manufacture comprising a ring or loop 6] having an enlarged end portion 52, in which is, a tapered socket or aperture 63. In. some-instances, the socket or aperture Gamay have a bushing, as at Ed, of a material providing a suitable bearing surface and, the, required wear, The bushing 56, whenthe body 3! is.com-. posed of cast metal, will be of a. harderor suit able bearing metal, or of fibrous material. Whereas, when the body BI is composed of. plastic material, the, bushing may, be composed, of. suitable metal, fiber or a diiferentplastic.

At 6,5,is shownapinmember haying a tapered shank ts fitting in the socket ea or the bushing 6 therein. At one endof theshank 6B is an en,-. largement in the form of a, ball member 51 and at the other end is a ring or eye 68. The ringer eye 68 joins the wide end of the shank in an enlarged annular collar portion 69 The ball end bl and collar E59 retain the loopor ring body 6] against displacement from the pin member 65..

In producing the article or product unit as seen in Fig. 1 0 of the drawing, a pair of similar die members it! are employed and adjacent abut-. ting surfaces of these die members will have cavities H and 12 for forming the respective parts BI and 65 as a single cast unit. These parts 6| and 65 are joined in thegate portion comprising the web Island the lateralextension 54. At 15 is shown a nozzle, through which heated casting material is adapted tobe pressure injected into the cavities ll, I2 through the gates 73, i l, as will be apparent.

In forming the unit comprising the parts BI and 8'5, the bushing 54 is arranged upon the tapered end 16 of acore pin H. When the bushing- 54 is not employed, the tapered. end. 16 will bemade to fitdirectlyin the-aperture or socket 630i the part 61, which socketin such instances, would have aplain wall structure.

From the foregoing, it will be apparent that when; the unit casting comprising the parts BI- and 6 5 is formed, it will be formed about the core pin 11. and, after formation, the dies will be separated and the unit casting moved into he loweredposition, in which position the part 6] will register with a partial cavity 18 in the dies Hi, conforming to the general outer contour ofthe upper portionof the part 65, as will readily appear from. a consideration of Fig. 8 of; thedrawingi. Inother words, the cavity 18 registers with the cavity 12, so that, in form-. ing the nextsuccessiye casting, after the core T! has been returned to its original position, the pin member will be cast within the socket of the loop-part 6i, of the pre-formed casting.

In the initialcasting operation, a dummy, substantially, similar to the part 6|, will be used in, the, cavity, 18 and preferably composed of split parts to facilitate detachment from the pin part 65, after the first casting has been formed. In production, cut off loop bodies 6! can be used as such dummies and saw cut through the socket portion 62 thereof.

From the foregoing, itwill be readily apparent. that, inproducing the article or product, as seen in'Fig. 10, the member or part BI is fcrmedfrom one. castunit, whereas the pin or member 65 is formed from the next, successive cast unit, in a eontinuous series of successive castings.

In some instances, where it is desirable to construct a continuous chain-like structure, instead of trimming off the gate portion 13 aswouldbe the case in the present teachings, these gate portions, as at 13., may be stoutly constructed toform astrong coupling between the ring '18 and the end. of the p body GI and the part [4 of the gate may be trimmed from the part 73.

In the above described operation of feeding the castunit downwardly to bring the part 6| in registering position with the impression i8, thediesaremoved into a partially closed position in, the operation of stripping the core l'l from this lowered cast unit preparatory to returning the same as to its, initial position, as shown in- Figs. 8 and 9. Inthis operation, the member 19 on one of the dies engages the loop part 6 '{ill supporting the casting against thepull of; the; core. The said die also includes portions 80, note Fig. 8, which maintains the casting in position, preparatory to closing the dies for the next successive casting operation.

In, forming the articles of manufacture of plastic materials, different nozzles or nozzles containing plastic materials of different colors may be intermittently moved into registering position with the gate '14, so that, in the resulting castings, the part 6! may be composed of one colored plastic and the part 65 of another colored plastic.

It will also be apparent that the shape and contour of the separate parts Bland 65 may be varied inmanyways to adapt these parts to the many uses of swivelled coupled parts of the kind under; consideration. It will also be apparent thatmy invention is not limited to the use of a tapered shank portion such as illustrated in the present disclosure of the invention.

Having fully described my invention, what I claim is new and desire to secure by Letters Patent is;

l. The method of'forming articles of manufacture of the class described, which comprises simultaneously die casting a pair-of members between relatively movable dies, forming on one member a socket portion and on the other member a pin portion, separating the dies, then moving said members collectively and positioning them so that said socket containing member projects into the die cavity wherein the pin containing member is formed, then closing the dies and forming a second pair of said members wherein the pin portion of the pin containing member of said second pair is cast within the socket portion of the socket containing member of the first pair to movably couple the latter two members, said movably coupled members being freely movable with respect to each other by virtue of the shrinkage of said pin portion within said socket portion upon the cooling of the pin portion.

2. The method of forming articles of manufacture of the class described, which comprises simultaneously die casting a pair of members between relatively movable dies and uniting said members together by means of gate portions, forming on one member a socket portion and on the other member a pin portion, separating the dies, then moving said socket and pin members collectively and positioning them so that said socket member projects into the die cavity wherein the pin member is formed, then closing the dies and forming a succeeding pair of socket and pin members wherein the pin portion of the pin member of said succeeding pair is cast within and through the socket portion of the socket member of the preceding pair to movably couple the latter two members, said movably coupled members being freely movable with respect to each other by virtue of the shrinkage of said pin portion within said socket portion upon the cooling of the pin portion, and trimming said gate portions to form movably coupled socket and pin members each comprising one member from one pair of simultaneously cast members and a member from the next succeeding pair of simultaneously cast members.

3. The method of forming articles of manufacture of the class described, which comprises simultaneously die casting a pair of members between relatively movable dies, forming on one member a socket portion and on the other memher a pin portion, separating the dies, then moving said socket and pin members collectively and a positioning them so that said socket member projects into the die cavity wherein the pin member is formed, then closing the dies and forming a succeeding pair of socket and pin members wherein the pin portion of the pin member of said succeeding pair is cast within and through the socket portion of the socket member of the preceding pair to movably couple the latter two members, said movably coupled members being freely movable with respect to each other by virtue of the shrinkage of said pin portion within said socket portion upon the cooling of the pin portion, and casting the socket member of each pair around a bushing to form a liner for the socket thereof.

4. The method of forming movably and permanently coupled die cast members, which comprises forming a die cast unit between relatively movable dies, wherein said unit comprises one member having a pair of socket portions formed around a core pin and another member having spaced recesses within which are arranged pintle portions, separating the dies, then feeding said unit relatively to the dies to position the socket portions of the firstmentioned member in aline-i ment with the pintle forming portions of said dies, partially closing the dies and stripping the core pin from said unit and returning the same to its original position between the dies, then closing the dies and forming another cast unit similar to the first unit, and casting the pintle portions of the second unit within socket portions of the first mentioned member of the first unit to movably and permanently couple one member of each unit.

5. The method of forming die cast hinges having interfitting pintle bearings on the leaves thereof, which comprises die casting a successive series of leaf units between relatively movable dies, forming the pintle bearings of one of the units around a core pin to produce sockets therein forming the other leaf of said unit in spaced relation to the first named leaf and joined through a gate portion, forming between the bearings of the second leaf of said unit pintle portions integral with said leaf, separating the dies and shifting the first unit by said core pin to bring the first leaf in registering position with the cavity of the die which formed the second leaf of the cast unit, stripping the core pin from the first cast unit and returning it to original position, and then forming the next successive cast unit with the pintle portions of the second leaf of said unit cast Within the sockets in the pintle bearings of the leaf of the first unit.

6. The method of forming die cast hinges having interfitting pintle bearings on the leaves thereof, which comprises die casting a successive series of leaf units between relatively movable dies, forming the pintle bearings of one of the units around a core pin to produce sockets therein forming the other leaf of said unit in spaced relation to the first named leaf and joined through a gate portion, forming between the bearings of the second leaf of said unit pintle portions integral with said leaf, separating the dies and shifting the first unit by said core pin to bring the first leaf in registering position with the cavity of the die which formed the secondv leaf of the cast unit, stripping the core pin from the first cast unit and returning it to original position, then forming the next successive cast unit with the pintle portions of the second leaf of said unit cast within the sockets in the pintle bearings of the leaf of the first unit, and then trimming the successive castings to remove the gates therefrom in forming hinges, each comprising one of the leaves of successive cast butt units.

'7. The method of forming die cast hinges having interfitting pintle bearings on the leaves thereof, which comprises die casting a successive series of leaf units between relatively movable dies, forming the pintle bearings of one of i the units around a core pin to produce sockets therein forming the other leaf of said unit in spaced relation to the first named leaf and joined through a gate portion, forming between the bearings of the second leaf of said unit pintle. portions integral with said leaf, separating the dies and shifting the first unit by said core pin to bring the first leaf in registering position with the cavity of the die which formed the second leaf of the cast unit, stripping the core pin from the first cast unit and returning it to original position, then forming the next successive cast unit with the pintle portions of the second leaf of said unit cast within the sockets in the pintle bearings of the leaf of the first unit, then trim- 75 mingrthev-successive castings to remove the gates therefrom in forming hinges, each comprising one of the leaves of successive cast butt units, forming countersunk apertures in each of 'said leaves, and arranging bushings on said core pin in providing bushing inserts in the socket portions of the bearings of the first leaves in each cast unit.

8. The method of forming buckles of the class described, which comprises die casting a buckle body and a hasp member as a single casting unit between relatively movable dies, forming one end of the hasp around a core pin to form a ring-like socket at said end of the hasp, forming a cylindrical bearing portion on the buckle body, then separating the dies and moving the casting to position the socket portion of the hasp in alinement with the cylindrical bearing forming portion of said dies, then removin the core pin and returning the same to the normal position thereof, then closing the dies, and forming the next successive casting with the bearing portion of the second casting formed in the socket portion of the hasp of the first casting.

9. The method of forming buckles of the class described, which comprises die casting a buckle body and a hasp member as a single casting unit between relatively movable dies, forming one end of the hasp around a core pin to form a ring-like socket at said end of the hasp, forming a cylindrical bearing portion on the buckle body, then separating the dies and moving the casting to position the socket portion of the hasp in alinement with the cylindrical bearing forming portion of said dies, then removing the core pin and returning the same to the normal position thereof, then closing the dies, forming the next successive casting with the bearing portion of the second casting formed in the socket portion of the hasp of the first casting, joining the buckle body and hasp of each casting in a gate portion, and then trimming the gate portions to form buckles each comprising a hasp of one castin and a buckle body of the next successive casting.

10. The method of forming buckles of the class described, which comprises die casting a buckle body and a hasp member as a single casting unit between relatively movable dies, forming one end of the hasp around a core pin to form a ring-like socket at said end of the hasp, forming a cylindrical bearing portion on the buckle body, then separating the dies and moving the casting to position the socket portion of the hasp in alinement with the cylindrical bearing forming portion of said dies, then removing the core pin and returning the same to the normal position thereof, then closing the dies, forming the next successive casting with the bearing portion of the sec- 0nd casting formed in the socket portion of the hasp of the first casting, joining the buckle body and hasp of each casting in a gate portion, then trimming the gate portions to form buckles each comprising a hasp of one casting and a buckle body of the next successive casting, and forming the socket portion of the hasp around a bushing insert supported on said core in producing on the resulting buckle a liner for said hasp.

11. The method of forming pairs of members swivelly coupled together, which comprises die casting a pair of united members on a core arranged between abutting surfaces of relatively movable dies with a portion of one of said members embracing the core to form an apertured portion, separatin the dies, moving the casting by moving said core into a different position between the dies, stripping the core from the casting, again closing the dies, and then forming a next successive casting which is a duplicate of the first, with one member of said next successive casting cast within and through the apertured portion of said first-mentioned member of said ire-positioned first named casting.

12. The method of forming pairs of members swivelly coupled together, which comprises die casting a pan of united members on a core arranged between abutting surfaces of relatively movable dies with a portion of one of said members embracing the core to form an apertured portion, separating the dies, moving the casting by moving said core into a different position between the dies, stripping the core from the casting, again closing the dies, then forming a next successive casting which is a duplicate of the first, with one member of said next successive casting cast within and through the apertured portion of said first-mentioned member of said re-positioned first named casting, and supporting an insert on the core in each casting operation to form of the insert a bushing for the apertured portion of the said first-mentioned member.

LOUIS H. MORIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 22,830- Squire Feb. 1, 1859 1,465,116 Dewire Aug. 14, 1923 1,535,350 Stacy Apr. 28, 1925 2,004,810 Hines June 11, 1935 2,243,062 Anderson May 27, 1941 2,266,433 Morin et a1. Dec. 16, 1941 2,387,013 Fuller Oct. 16, 1945

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