US2368260A - Method of casting a series and a portion of a series of scoops - Google Patents

Method of casting a series and a portion of a series of scoops Download PDF

Info

Publication number
US2368260A
US2368260A US460067A US46006742A US2368260A US 2368260 A US2368260 A US 2368260A US 460067 A US460067 A US 460067A US 46006742 A US46006742 A US 46006742A US 2368260 A US2368260 A US 2368260A
Authority
US
United States
Prior art keywords
scoops
series
casting
cavities
mounting member
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 - Lifetime
Application number
US460067A
Inventor
Louis H Morin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US460067A priority Critical patent/US2368260A/en
Priority to US528121A priority patent/US2467047A/en
Application granted granted Critical
Publication of US2368260A publication Critical patent/US2368260A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/14Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
    • B29C45/14549Coating rod-like, wire-like or belt-like articles
    • B29C45/14565Coating rod-like, wire-like or belt-like articles at spaced locations, e.g. coaxial-cable wires
    • B29C45/14573Coating the edge of the article, e.g. for slide-fasteners

Definitions

  • This invention relates to the formation ofwhat are known as stringer lengths, in the production of separable fasteners of the type employing stringers coupled and uncoupled by a slider movable along the stringers. More particularly, the invention comprises a method of casting a series or multiple of scoops successively along a mounting tape or strand, and, as required, to decrease the number of scoops cast in a series in producing predetermined stringer lengths or stringers having a predetermined number of scoops thereon. Further, the invention includes a. method in which the stringer lengths on the mounting strand or tape are spaced as to produce on a single mounting any desired number or the predetermined stringer lengths.
  • Fig. 1 is a diagrammatic view illustrating such mechanism
  • Fig. 2 is a diagrammatic detailed view of a part of the structure illustrated in Fig. 1.
  • separable fastener stringers also a waste in material and further results in the production ofmakeshiit, partially marred stringers, involving the dilliculty of removing the cast material from the interstices of the braid of the mounting member.
  • an automatic die casting machine such, for example, as that disclosed in Patent 2,244,425 of June 3, 1941, may be utilized and the spacing between the series of scoops for each stringer along the strand, tape, or other mounting so that such mounting may be subdivided to produce separate stringers may be obtained by utilizing, in whole or in part, mechanism such as is shown in my prior Patents 2,224,980 of December 17, 1940, and 2,228,145 of January 7, 1941.
  • Fig. 1, 5 represents a die or at least the face view of one part of a die having a series of im- 'pressions or cavities 6, 1, 8. and 9 therein to form a corresponding number of scoops of a separable fastener stringer. These scoops are formed at spaced intervals along the beaded edge III of a tape I l or other mounting member also supported between the dies 01' the machine.
  • the parting line of the die head ID of the tape. is a core of castings.
  • a selecting core is, which acts as a valve to runners l3, l4, l5, and I6 leading to the impressions or cavitie 6, l, I, and 9 for purposes later described.
  • the core pin i1 is mounted in a slide 2
  • the core-pin I! is stripped from the scoops 23 by the partial closing of the dies I to engage the scoops.
  • the selecting core I! could be moved manually to close off as many of the runners M, ii, and I8 as may be desired in any particular casting operation, but, preferably, this core will be moved automatically.
  • the selecting core I9 as mounted on a slide 2 having at its upper end a piston 25 which operates in an air cylinder 26. Air is admitted into the cylinder 26 below the piston through a port 21, and this air supply is controlled by a valve 28.
  • a valve 28 In the valve 28 is a valve stem or plunger 28 carrying at its outer end a roller 30 which operates upon the links of a control chain 3
  • the valve 28 has an inlet port 32 communicating with a source of compressed air supply.
  • the stem 29 In the stem 29 is a passage 33 to place the port 32 in communication with a discharge port 34 which communicates with the port 21 through a pipe or tube indicated by the line 35.
  • the above communication is established when the roller 30 operates upon the normal links of the chain 3
  • the stem 29 is raised by a tripping lug 36 to close the port 32 and to bring the passage 33 in communication with an exhaust port 31 to exhaust the air from the cylinder 28.
  • a spring 38 supports the roller 30 in constant engagement with the chain 3
  • the piston 25 When the air is released from the cylinder 26, the piston 25 is depressed by a spring 35 to move the piston into engagement with an adjustable Stop screw 40 or similar control.
  • the screw 40 is adjusted to a position to check downward movement of the piston 25 to the extent to close all of the branches or runners M, i5, and I by the core l9, leaving the runner i3 open, so that in the next casting operation a single scoop 4
  • This means that a single scoop is added to any multiple of the series of 4 castings made in producing a given stringer length. For example, if 1? scoops are required,.there will be 4 castings of the 4 series of scoops and the added single cast scoop 41. If 18 scoops are required, then the screw 40 would be adjusted to expose the runners l3 and I to form scoops in the cavities 6 and I, and if 19 are required, the added runner i5 would be exposed to form a casting in the cavity 8.
  • is made of such length as to control and regulate the particular stringer to be produced, and this chain willhave one of the trips 36 thereon to timely actuate the valve in exhausting the air from the cylinder to allow the member of the stringer,
  • th trip 35 will be arranged at one side of the chain, whereas the trips l2 will be arranged at the other side thereof, as diagrammatically illustrated in Fig. 2 of the drawing.
  • my present invention generally, it may be said to comprise a method wherein a plurality or series of castings are formed normally in each casting operation of the machine, and
  • these series of casting are repeated in a controlled series of casting operations, and then in one casting operation only a part of the series of castings is formed. Particularly, when all of the castings in one cycle will not make up the required number of castings in what might be termed a group of castings, the final casting operation of the machine reduces the number of castings formed to make up the exact number of castings required in a group.
  • the method of forming separable fastener stringers of lengths defined by a predetermined number of scoops arranged on the mounting which comprises supporting a mounting member between relatively movable dies, having a predetermined number of scoop cavities defining a series of scoops, pressure injecting casting material into the die cavitie and around the mounting member in forming said series of scoops, casting said series of scoops on a core member, separating the dies and moving the cast series of scoops together with the mounting member to position a new section of the mounting member in registering allusement wlththe die cavities, stripping the first series of cast scoops from said core member, again closing the dies and casting another series of scoops, and then, in one casting operation, blocking off a predetermined number of the scoop cavities to form, in such casting operation, a part only of the complete series of scoops in producing the desired number of scoops on the resulting stringer length.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Moulds For Moulding Plastics Or The Like (AREA)

Description

Jan. 30, 1945. 4 L H. MORIN 2,368,260
METHOD OF CASTING A SERIES AND A PORTION OF A SERIES OF SCOOPS Filed Sept. 29, 1942 INVENTOR Lou/6 H. Mom/v ATTORNE Patented Jan. 30, 1945 2,368,280 7 METHOD or CASTING A seams AND A POR- TION OF A saunas OF SCOOPS Louis H. ltiorin, Bronx, 1N. Y., assignor of onehalf to Davis 'Marinsky,
Application September 29, 1942, Serial No. 460,067
7 Claims.
This invention relates to the formation ofwhat are known as stringer lengths, in the production of separable fasteners of the type employing stringers coupled and uncoupled by a slider movable along the stringers. More particularly, the invention comprises a method of casting a series or multiple of scoops successively along a mounting tape or strand, and, as required, to decrease the number of scoops cast in a series in producing predetermined stringer lengths or stringers having a predetermined number of scoops thereon. Further, the invention includes a. method in which the stringer lengths on the mounting strand or tape are spaced as to produce on a single mounting any desired number or the predetermined stringer lengths.
The invention will be best understood from the following description and the accompanying drawing, which discloses certain mechanisms which may be employed in connection with the invention, the separate parts of such mechanism being "designated by suitable reference characters in each of the views.
In the drawing, Fig. 1 is a diagrammatic view illustrating such mechanism, and
Fig. 2 is a diagrammatic detailed view of a part of the structure illustrated in Fig. 1.
In the formation of of the type and kind under consideration, particularly in die casting a series or multiple scoops on a mounting member, it has been diilicult to produce stringers of the required length. For example, let use assume that four scoops are cast in each operation of the machine. In such case, if 16 scoops were desired on the resulting stringer, 4 casting operations would suilice to produce this stringer. If, however, a stringer, let us say, of 17 scoops was required, it would be necessary to cast stringers of scoop lengths, and then remove 3 of the scoops.
The above objectionable features not only necessitates undue waste of time and labor, but
separable fastener stringers also a waste in material and further results in the production ofmakeshiit, partially marred stringers, involving the dilliculty of removing the cast material from the interstices of the braid of the mounting member.
To overcome this objection, I have conceived a method whereby the last series of castings in producing a predetermined stringer length may be modified to the extent of eliminating any desired portion of the series of scoops; for instance when casting in series of 4, to eliminate 1, 2, or 3 of the 4 scoops.
In carrying out my novel method, an automatic die casting machine, such, for example, as that disclosed in Patent 2,244,425 of June 3, 1941, may be utilized and the spacing between the series of scoops for each stringer along the strand, tape, or other mounting so that such mounting may be subdivided to produce separate stringers may be obtained by utilizing, in whole or in part, mechanism such as is shown in my prior Patents 2,224,980 of December 17, 1940, and 2,228,145 of January 7, 1941. The drawing diagrammatically illustrates a form of mechanism which may be used in carrying out my invention, though it is obvious that other forms may be used and that, if desired, some or the stepspf my method could be carried out'by hand.
In Fig. 1, 5 represents a die or at least the face view of one part of a die having a series of im- 'pressions or cavities 6, 1, 8. and 9 therein to form a corresponding number of scoops of a separable fastener stringer. These scoops are formed at spaced intervals along the beaded edge III of a tape I l or other mounting member also supported between the dies 01' the machine.
Also formed on a large gate l2 l3, II, II, pendent impressions Also arranged on and I6 leading to the indeor cavities 8 to 8 respectively. the parting line of the die, head ID of the tape. is a core of castings. Also on the parting line of the die and extending into the gate I2, is a selecting core is, which acts as a valve to runners l3, l4, l5, and I6 leading to the impressions or cavitie 6, l, I, and 9 for purposes later described.
At 20 is indicated the discharge end of the nozzle of a casting machine through which casting material is pressure-injected into the dies to 1111 the cavities or impressions 6 to 9 or such portion of these cavities as may not be shut on by the selecting core I 9. Obviously, any suitable metallic or plastic material may be'used.
The core pin i1 is mounted in a slide 2| which is actuated through a lever 22, in feeding the cast series to the position It, in which position they are held by an impresssion in the dies 5 conforming to the complete casting as indicated in the drawing. The core-pin I! is stripped from the scoops 23 by the partial closing of the dies I to engage the scoops.
Obviously, the selecting core I! could be moved manually to close off as many of the runners M, ii, and I8 as may be desired in any particular casting operation, but, preferably, this core will be moved automatically. For this purpose, I have shown the selecting core I9 as mounted on a slide 2 having at its upper end a piston 25 which operates in an air cylinder 26. Air is admitted into the cylinder 26 below the piston through a port 21, and this air supply is controlled by a valve 28. In the valve 28 is a valve stem or plunger 28 carrying at its outer end a roller 30 which operates upon the links of a control chain 3|. The valve 28 has an inlet port 32 communicating with a source of compressed air supply. In the stem 29 is a passage 33 to place the port 32 in communication with a discharge port 34 which communicates with the port 21 through a pipe or tube indicated by the line 35. The above communication is established when the roller 30 operates upon the normal links of the chain 3|. However, the stem 29 is raised by a tripping lug 36 to close the port 32 and to bring the passage 33 in communication with an exhaust port 31 to exhaust the air from the cylinder 28. A spring 38 supports the roller 30 in constant engagement with the chain 3|.
When the air is released from the cylinder 26, the piston 25 is depressed by a spring 35 to move the piston into engagement with an adjustable Stop screw 40 or similar control. In the present diagrammatic illustration the screw 40 is adjusted to a position to check downward movement of the piston 25 to the extent to close all of the branches or runners M, i5, and I by the core l9, leaving the runner i3 open, so that in the next casting operation a single scoop 4| will be formed in the cavity 5. This means that a single scoop is added to any multiple of the series of 4 castings made in producing a given stringer length. For example, if 1? scoops are required,.there will be 4 castings of the 4 series of scoops and the added single cast scoop 41. If 18 scoops are required, then the screw 40 would be adjusted to expose the runners l3 and I to form scoops in the cavities 6 and I, and if 19 are required, the added runner i5 would be exposed to form a casting in the cavity 8.
At this time it is well to point out that in forming stringer lengths a predetermined number of stringers of one length are made to fill a predetermined order, and after the machine is once set by the adjustment of the screw 40, the machine will continue to automatically produce all of the required stringers of the one predetermined or desired length. In proceeding to produce a quantity of another stringer length, suitable adjustments will be made, as will be apparent.
The control chain 3| is made of such length as to control and regulate the particular stringer to be produced, and this chain willhave one of the trips 36 thereon to timely actuate the valve in exhausting the air from the cylinder to allow the member of the stringer,
core I9 to drop into its control position. Intermediate this tripping period, the valve is supported in position to maintain air in the cylinder, thus supporting the core IS in raised position.
Also provided on the chain 3| are one or more other trip lugs 42, with which a lever or other control 43 operates in controlling the wide spacing of the tape or other mounting H, to space one stringer length from another in accordance with the teachings in the patents herein before cited. In this connection, and bearing in mind that two controls are employed on the chain 3|, th trip 35 will be arranged at one side of the chain, whereas the trips l2 will be arranged at the other side thereof, as diagrammatically illustrated in Fig. 2 of the drawing.
It will, of course, be apparent that the present diagrammatic illustration is simply to indicate one adaptation of the invention, as the scoops may be cast in any desired multiple, that is to say, two or more. While one type or form of scoop is shown, this again is simply to illustrate one adaptation of the invention.
Considering my present invention generally, it may be said to comprise a method wherein a plurality or series of castings are formed normally in each casting operation of the machine, and
these series of casting are repeated in a controlled series of casting operations, and then in one casting operation only a part of the series of castings is formed. Particularly, when all of the castings in one cycle will not make up the required number of castings in what might be termed a group of castings, the final casting operation of the machine reduces the number of castings formed to make up the exact number of castings required in a group.
From this standpoint it will be apparent that in the art of producing die castings, it will be possible to control group formation of, castings for any desired purpose, that is to say, for boxing, sorting, and the like. Here again it is also to be borne in mind that it is not essential that the castings be formed on a mounting member, and in other instances, the mounting member, if employed, may simply constitute a means for supporting or retaining each group of castings in a coupled or united relationship.
Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:
1. The method of forming separable fastener stringers of lengths defined by a predetermined number of scoops arranged on the mounting which comprises supporting a mounting member between relatively movable dies, having a predetermined number of scoop cavities defining a series of scoops, pressure injecting casting material into the die cavitie and around the mounting member in forming said series of scoops, casting said series of scoops on a core member, separating the dies and moving the cast series of scoops together with the mounting member to position a new section of the mounting member in registering allnement wlththe die cavities, stripping the first series of cast scoops from said core member, again closing the dies and casting another series of scoops, and then, in one casting operation, blocking off a predetermined number of the scoop cavities to form, in such casting operation, a part only of the complete series of scoops in producing the desired number of scoops on the resulting stringer length.
2. The method of forming separable fastener stringers of lengths defined by a predetermined number of scoops arranged on the mounting member of the stringer, which comprises supporting a mounting member between relatively movable dies, having a predetermined number of scoop cavities defining a series of scoops, pressure injecting casting material into the die cavities and around the mounting member in forming said series of scoops, casting said series of scoops on a core member, separating the dies and moving the cast series of scoops together with the mountin member to position a new section of the mounting member in registering alinement with the die cavities, stripping the first series of cast scoops from said core member, again closing the dies and casting another series of scoops, then, in one casting operation, blocking of! a predetermined number of the scoop cavities to dorm, in such casting operation, a part only of the complete series of scoops in producing the desired number of scoops on the resulting stringer length, and then feeding the mounting member relatively to the dies to space one stringer length from an adjacent stringer length on said mounting member.
3. The method of forming Scoops of separable fastener stringers on a mounting member of predetermined length by the use of a single mold having a plurality of cavities therein, which oomprises successively casting a number of scoops on spaced sections of said mounting member, equal to the number .of cavities in the mold, to provide a series of scoops on said mounting member which is a multiple of the number of cavities in the mold, and thereafter casting on said mounting member, :by the use of the same mold, a number of scoops which is less than the number of cavities in said mold, by blocking a plurality of said cavities, in producing scoops on the mounting member defining a stringer length.
4. The method of forming a predetermined number of similar die cast articles on an elongated mounting by the use of a single mold having a plurality of similar cavities alined therein, which comprises successively forming a number of castings on said mounting, each comprising articles formed from all of the cavities of said mold in producing a series of cast articles comprising a multiple of the number of cavities in the mold, and thereafter in one casting operation, forming on said mounting, by the use of the same mold, a number of articles less than the number of cavities in said mold by blocking a part of said cavities, and thereby producing on said mounting the predetermined number of cast articles desired.
5. The method of forming a predetermined number of die cast devices on a mounting member by the use of a single mold having a plurality of cavities therein, each cavity defining one of said devices, which comprises successively forming a. plurality of castings spaced along the mounting member, each casting including devices formed by all of the cavities of said mold, thereby producing in said series of casting operations a multiple of the number of devices characterized by the cavities in the mold, and thereafter in one casting operation blocking ofl part of the cavities of the same mold in producing a number of devices in said last casting operation, which is less than the number of cavities in said mold in defining the predetermined number of cast devices formed on said mounting member.
6. The method of forming a predetermined number of die cast devices on a mounting memher by the use of a single mold having a plurality of cavities therein, each cavity defining one of said devices, which comprises successively forming a plurality of castings spaced along the mounting member, each casting including devices formed by all of the cavities of said mold, thereby producing in said series of casting operationsa multiple of the number of devices characterized by the cavities in the mold, thereafter in one casting operation blocking oif part of the cavities of the same mold in producing .a number of ,devices in said last castin operation, which is less than the number of cavities in said mold in defining the predetermined number of cast devices formedon said mounting member, and then feeding the mounting member to widely space the same preparatory to forming the next predetermined number of cast devices thereon.
7. The method of forming a predetermined number of die cast devices on a mounting member by the use of a single mold having a plurality of cavities therein, each cavity defining one of said devices, which comprises successively forming a plurality of castings spaced along the mounting member, each casting including de vices formed by all of the cavities of said mold, thereby producing in said series of casting operations a multiple of the number of devices characterized by the cavities in the mold, thereafter in one casting operation blocking off part of the cavities of the same mold in producing a number of devices in said last casting operation, which is less than the number of cavities in said mold in defining the predetermined number of cast devices formed on said mounting member, forming all of the cast devices in each casting operation on a core, and utilizing the core as a means for ejecting the castings from the dies and for feeding the mounting member to bring successive sections thereof in position to receive successive castings.
LOUIS H. MORIN.
US460067A 1942-09-29 1942-09-29 Method of casting a series and a portion of a series of scoops Expired - Lifetime US2368260A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US460067A US2368260A (en) 1942-09-29 1942-09-29 Method of casting a series and a portion of a series of scoops
US528121A US2467047A (en) 1942-09-29 1944-03-25 Die casting machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US460067A US2368260A (en) 1942-09-29 1942-09-29 Method of casting a series and a portion of a series of scoops

Publications (1)

Publication Number Publication Date
US2368260A true US2368260A (en) 1945-01-30

Family

ID=23827284

Family Applications (1)

Application Number Title Priority Date Filing Date
US460067A Expired - Lifetime US2368260A (en) 1942-09-29 1942-09-29 Method of casting a series and a portion of a series of scoops

Country Status (1)

Country Link
US (1) US2368260A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460102A (en) * 1944-10-25 1949-01-25 Louis H Morin Method of controlling the lengths of separable fasteners
US2495592A (en) * 1945-01-17 1950-01-24 Louis H Morin Method of forming separable fastener stringers
US2516086A (en) * 1945-01-19 1950-07-18 Winterhalter Martin Apparatus and method for the manufacture of separable fasteners
US2523463A (en) * 1947-10-13 1950-09-26 Waldes Kohinoor Inc Slide fastener manufacture and mold therefor
US2695419A (en) * 1950-03-20 1954-11-30 Louis H Morin Apparatus for controlling tape spacing between separable fastener stringer lengths
US2728110A (en) * 1950-09-14 1955-12-27 Louis H Morin Method of controlling high speed die casting production
FR2430301A1 (en) * 1978-07-04 1980-02-01 Yoshida Kogyo Kk INJECTION MOLDING APPARATUS FOR A CONTINUOUS SLIDE CLOSURE CHAIN

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460102A (en) * 1944-10-25 1949-01-25 Louis H Morin Method of controlling the lengths of separable fasteners
US2495592A (en) * 1945-01-17 1950-01-24 Louis H Morin Method of forming separable fastener stringers
US2516086A (en) * 1945-01-19 1950-07-18 Winterhalter Martin Apparatus and method for the manufacture of separable fasteners
US2523463A (en) * 1947-10-13 1950-09-26 Waldes Kohinoor Inc Slide fastener manufacture and mold therefor
US2695419A (en) * 1950-03-20 1954-11-30 Louis H Morin Apparatus for controlling tape spacing between separable fastener stringer lengths
US2728110A (en) * 1950-09-14 1955-12-27 Louis H Morin Method of controlling high speed die casting production
FR2430301A1 (en) * 1978-07-04 1980-02-01 Yoshida Kogyo Kk INJECTION MOLDING APPARATUS FOR A CONTINUOUS SLIDE CLOSURE CHAIN

Similar Documents

Publication Publication Date Title
US3068522A (en) Method and apparatus for molding covers on spherical bodies
US2266432A (en) Method of die casting heads on pins
US2569083A (en) Method and apparatus for molding and trimming
US2368260A (en) Method of casting a series and a portion of a series of scoops
US2494777A (en) Injection mold with sprue severing means
US2102328A (en) Method of making thermoplastic fasteners
US2300302A (en) Apparatus for forming castings from powdered metals
US2388986A (en) Apparatus for producing intercoupled relatively movable castings
US2584916A (en) Method of making die-cast sliders
US2864123A (en) Molding methods and apparatus
US2497951A (en) Mold for slide fasteners
US3178772A (en) Apparatus for controlling tape feed in regulating variable spacings between groups of scoops
US2467047A (en) Die casting machine
US2447355A (en) Die-casting machine
US2742670A (en) Means for casting complete stringer lengths
US2322908A (en) Slide fastener
US2227461A (en) Method of intermittently casting variably colored thermoplastics
US2042541A (en) Method of making riders
US3068519A (en) Method and apparatus for casting multiple plastic scoops and controlling predetermine stringer lengths
US2252090A (en) Means and method of forming separable fastener stringers
US2581854A (en) Method of freeing and ejecting die castings formed on cores
US3263013A (en) Intercast relatively movable plastic elements and method of forming the same
CN111002535B (en) Wear-resistant durable injection mold
US2543111A (en) Apparatus for molding plastic slide fasteners
US2262193A (en) Method of forming and mounting thermoplastic fasteners