GB1565613A

GB1565613A - Method of and apparatus for producing sliding clasp fastener stringers

Info

Publication number: GB1565613A
Application number: GB688577A
Authority: GB
Original assignee: Yoshida Kogyo KK
Current assignee: YKK Corp
Priority date: 1976-02-21
Filing date: 1977-02-18
Publication date: 1980-04-23
Also published as: FR2341420B1; JPS52103247A; BE851659A; DE2707369C2; JPS599331B2; DE2707369A1; IT1082467B; FR2341420A1; ES456073A1; NL7701743A

Description

(54) METHOD OF AND APPARATUS FOR PRODUCING SLIDING CLASP FASTENER STRINGERS (71) We, YOSHIDA KOGYO K.K., a corporation duly organized under the laws of Japan and existing at No. 1, Kanda Izumicho, Chiyoda-ku, Tokyo, Japan, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a method of and an apparatus for producing a pair of elongated strings of a sliding clasp fastener.

According to one aspect of the invention; there is provided a method of producing a sliding clasp fastener stringer comprising the steps of: providing an upper endless chain of mould blocks and a lower endless chain of mould blocks, each mould block having a mould face with a series of equally spaced half mould cavities and a half channel formed therein; transferring a mould block of the upper chain and a mould block of the lower chain into a position in which said mould blocks are mated together as a pair at said faces to provide a mould having a series of equally spaced mould cavities and a channel, and in which said mould cavities each communicate with a respective one of a plurality of branch runners in a hot runner manifold which is supplied with a molten material under pressure; accommodating a stringer tape in said channel with a beaded edge of the tape disposed in said mould cavities; feeding the molten material under pressure through said branch runners into said series of mould cavities; moving said mould, filled with the molten material, to another position in which the molten material solidifies to form a series of discrete fastener elements on said beaded tape edge corresponding to the series of mould cavities; and thereafter parting said pair of mould blocks.

According to another aspect of the invention, there is also provided an apparatus for producing a sliding clasp fastener stringer, comprising an upper endless chain of mould blocks and a lower endless chain of mould blocks, each mould block having a mould face with a series of equally spaced half mould cavities and a half channel formed therein; means for moving a mould block of the upper chain and a mould block of the lower chain to a position in which said mould blocks are mated together as a pair at said faces to provide a mould having a series of equally spaced mould cavities and a channel for receiving a stringer tape with a beaded edge in said mould cavities; two pairs of spaced drive sprockets over which said upper and lower mould block chains run, respectively, said drive sprockets being rotatable intermittently; a hot runner manifold having a plurality of branch runners and arranged to be supplied with a molten material under pressure; means for holding said series of mould cavities in communication with said branch runners for receiving the molten material in said position; means for moving said mould, after being filled with the molten material to another position in which the molten material solidifies to form a series of discrete fastener elements on said beaded tape edge corresponding to the series of mould cavities and means for thereafter scparating the pair of mould blocks.

The invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic front elevational view of an apparatus constructed in accordance with the invention; Figure 2 is an enlarged cross-sectional view taken along line II--II of Figure 1; Figure 3 is ac ross-sectional view, on a reduced scale, taken along line IIIIII of Figure 2; Figure 4A is a fragmentary plan view of fastener elements moulded on a beaded tape edge in accordance with the invention; Figure 4B is an enlarged perspective view of one of the fastener elements shown in Figure 4A; Figure 5A is a fragmentary plan view of fastener elements moulded on a beaded tape edge in accordance with the invention; Figure 5B is an enlarged perspective view of one of the fastener elements shown in Figure SA; Figure 6 is a fragmentary plan view of a pair of fastener stringers each having a series of discrete fastener elements on and along the entire length of its beaded tape edge; and Figure 7 is a fragmentary plan view of a pair of fastener stringers each having a series of discrete fastener elements on and along its beaded tape edge with element-free gaps at spaced intervals.

In Figure 1, an injection-moulding apparatus generally designated by the numeral 10 broadly comprises a pair of upper and lower mould assemblies 11, 12, one of which is the mirror image of the other, and a central injection-moulding station 13 where the upper and lower mould assemblies 11, 12 coact on their one-way travel with each other at three different but consecutive positions as described later on. The upper mould assembly 11 comprises a pair of endless chains of mould parts or blocks 14, 14 spaced apart horizontally (Figure 2). The mould blocks in each chain are hingedly interconnected end to end and run over a pair of spaced drive sprockets 15, 15 located upstream and downstream, respectively, of the injection-moulding station 13.

Likewise, the lower mould assembly 12 comprises a pair of endless chains of moulded parts or blocks 16, 16 spaced apart horizontally (Figure 2). The mould blocks in each chain are hinged end to end and span over a pair of spaced drive sprockets 17, 17 underlying the sprockets 15, 15 in spaced relation. Each sprocket has a crosssection of a regular octagon of which peripheral sides have the same length as that of the mould blocks, so that the linked mould blocks can be held flat against the peripheral sides of the sprockets and driven positively by the sprockets as the latter are rotated.

In operation, the drive sprockets are rotated intermittently in the direction of, for example, the arrows 18 to enable the lower runs of the upper mould block chains to travel with the upper runs of the lower mould block chains intermittently in the direction of the arrow 19.

The central injection-moulding station 13 has three successive positions in which the upper and lower mould blocks 14, 16 are combined together to provide moulds 20 in which a pair of series of discrete fastener elements 21 are to be formed. In a first or upstream position 22, separated upper and lower mould blocks 14, 16 become mated in face-to-face alignment preparatory for injection-moulding. The moulds 20 are then moved to and stopped in a second or middle position 23 in which they are supplied with a molten material such as plastics or metal.

As the moulds 20 are transferred to, and while they are held in a third or downstream position 24, the injected molten material cools and solidifies. At this time, next empty moulds 20 are supplied under pressure and filled up with the molten material in the middle portion 23.

As shown in Figures 2 and 3, each of the upper and lower mould blocks 14, 16 has a mould face 25 with a series of equally spaced half mould cavities 26 formed therein along its one edge and a channel half 27 formed therein, channel half 27 extending uninterruptedly the whole length of the mould block. Between the half mould cavity 26 and the channel half 27, there is a grip leg 28 extending slightly short of the general plane of the mould face 25. As best shown in Figure 3, the half mould cavities 26 are spaced apart from one another a distance equal to a desired element-to-element pith.

Each pair of adjacent half mould cavities 26 are separated by a partition half 29 having therein a semi-circular recess for receiving a beaded tape edge 30 and another semi-circular recess for receiving a fixed rod 31 of which the purpose will be described later.

Each mould cavity half 26 represents one-half of a mould cavity 32 in which the fastener element 21 is to be moulded. and each channel half 27 represents one-half of a channel 33 in which a fastener stringer tape 34 is to be accommodated.

During injection-moulding operation, the upper and lower mould blocks 14, 16 are held in accurate registry at the injectionmoulding station 13. Although not shown, dowel pins and complementary apertures, for example, should be used to provide accurate registration. Furthermore, the coacting mould faces 25 are carefully machined to close tolerances whereby the mould cavities 32 are sharply defined while the upper and lower moulds 14, 16 are mated together.

A hot runner manifold 35 is located in the second position 23 and interposed between the moulds 20, 20 in side-by-side contact therewith. The manifold 35 is equal in length to each mould 20 and has therein a central, vertical feed sprue 36, a horizontal main runner 37 extending longitudinally of the manifold 35, and a plurality of branch runners 38 extending at a right angle from the main runner 37 and spaced apart from each other at a regular interval which corresponds to the element-to-element pitch. The branch runners 38 open through gates 39 at both lateral sides of the manifold 35.

When the moulds 20 are positioned along- side of the manifold 35 and contact with its lateral sides in exact registry, the branch runners 38 are held in communication with the mould cavities 32 in the closed moulds 20.

Mounted on the manifold 35 is a nozzle 40 having a central bore 41 therein which communicates through an orifice 42 with the fed sprue 36 to supply the manifold 35 with the molten material. The nozzle 40 has a needle 43 disposed coaxially in the central bore 41, the needle 43 being vertically movable to open and close the orifice 42 so as to control the flow of the fluidized material therethrough. The hot runner manifold 35 contains therein heaters 43 which keep the molten material in fluidized state within the manifold 35.

The side wall of each mould block which is held against the lateral side of the hot runner manifold 35 is recessed at 44 to reduce an area of contact as much as possible so that heat transfer or heat dissipation from the manifold 35 can be held at a minimum.

The injection-moulding station 13 illustrated in Figure 1 is provided with a support 45 having a plurality of support rollers 46 on which ride the moulds 20 located in the first to third positions 22-24. While the moulds 20 receive the molten material from the manifold 35 in the middle position 23, the upper and lower mould blocks 14, 16 are tightened together against leakage of the molten material under pressure by means of side rollers 47 and top rollers 48 held in rolling engagement therewith. A pair of guide rollers 49, 50 are also provided upstream and downstream, respectively, of these tightening rollers 47, 48. The roller 49 serves to maintain the mould blocks 14, 16 in the first position 22 tightly together in preparation for injection-moulding operation. The mould blocks 14, 16 having moved past the middle position 23 are mated together by the roller 50 against parting during solidification of the molten material that fills up the mould cavities 32.

The nozzle 40 is connected with a heated chamber 51 from which the molten material is fed under pressure in the usual manner.

The fixed rod 31 is one of a pair and extends in and through the mould cavities 32 in the mated upper and lower mould blocks 14, 16. Each rod 31 has one end secured to a fixed support 42 located upstream of the sprockets 15, 17 and the other free end extending as far as a remoter end of the manifold 35.

For moulding series of discrete fastener elements 21, a pair of stringer tapes 33, 34 each having the beaded edge 30 are introduced in between the upstream sprockets 15, 17 toward the injection-moulding station 13 and are placed between the upper and lower mould blocks 14, 16 fitted together at the middle position 23 in the injection-moulding station 13. The stringer tapes 34, 34 are inserted in the tape receiving channels 33, 33 extending all the way through the closed moulds 20 on the support 45. The opposed grip legs 28 sandwich therebetween the stringer tapes 34, 34 adjacent to the beaded edges 30, 30. The beaded tape edges 30 are disposed in the mould cavities 32 and received for precise positioning in the recesses in the spaced partitions that are formed by the mated partition halves 29.

With the stringer tapes 34, 34 thus retained in the moulds 20, 20, the needle 43 in the nozzle 40 is lifted to allow the molten material to be forced under pressure through the feed sprue 36, then through the main and branch runners 37, 38 and on through the gates 39 into the mould cavities 32. After the mould cavities 32 are filled up with the molten material, the needle 43 is lowered to shut off the molten flow. The fluidized material upon entering the mould cavities 32 begins to cool and congeal. Then, the drive sprockets 15, 17 are revolved to bring the material-filled moulds 20 and the stringer tapes 34 therein down to the third position 24 for solidification and formation of the fastener elements 21. Since the hot runner manifold 35 enables the molten material to remain fluidized in the gates 39, the moulds 20 can be moved relatively to the manifold 35 without substantial resistance. At this time, the empty moulds 20 located in the first position 22 are transferred to the middle position 23 for injection-moulding. Upon further revolution of the drive sprockets 15, 17, the moulds 20 in the third position 24 are parted into the upper and lower mould blocks 14, 16 to thereby produce a series of fastener elements 21 at a time for an interval corresponding to the length of the moulds 20.

Thus, injection-moulding operation is repeated to form a pair of fastener stringers in an intermittent step-like manner.

Since the rods 31 are fixed at one ends, the molten material having filled the mould cavities 32 in the moulds 20 at the middle position 23 and started solidification slides over the rods 31 as the moulds 20 are shifted from the middle position 23 to the third position 24. With the rods 31 thus utilized, the formed discrete elements 21 are each provided with a through hole 53 just behind its head portion 54 as shown in Figures 4A and 4B, the hole 53 serving as a pocket in which the head of an opposed mating fastener element can partly be received for positive and stable interlocking engagement. Provision of the fixed rods 31 is advantageous also in that the molten material iniected under pressure through the gates 39 impinges upon the rods 31 rather than striking directly against the beaded tape edges 30, thereby preventing the beaded edges 30 from being deformed.

To form discrete fastener elements 55 shown in Figures 5A and 5B, the upper and lower mould blocks 14, 16 have their mould cavity halves shaped to different configurations complementary to the upper and lower portions of the element 55. Furthermore, the fixed rods 31 are not necessary.

A pair of series of discrete fastener elements 21 shown in Figure 6 can be injectionmoulded by feeding the molten material to all the moulds 20 which are successively transeferred to and intermittently stopped in the middle position 23.

By supplying the molten material only to selected moulds 20 in the middle position 23 and allowing empty moulds 20 to go past the manifold 35 at suitable intervals, the injection-moulding apparatus 10 can produce a pair of fastener stringers shown in Figure 7 each having a series of discrete elements 21 on and along its beaded edge with element-free gaps 56 at spaced intervals. The element-free gap 56 can be changed in length by permitting empty moulds 20 to get successively past the manifold 35 as many as desired, or varying the length of the moulds 20, that is, altering the number of the mould cavities 32 in the moulds 20.

An advantage resulting from the apparatus as illustrated and described is that the discrete fastener elements 21 thus formed are free of any excessive material such as sprues, gates, and runners which would be produced in existing injection-moulding apparatus and should be removed for finishing.

WHAT WE CLAIM IS:- 1. A method of producing a sliding clasp fastener stringer comprising the steps of: providing an upper endless chain of mould blocks and a lower endless chain of mould blocks, each mould block having a mould face with a series of equally spaced half mould cavities and a half channel formed therein; transferring a mould block of the upper chain and a mould block of the lower chain into a position in which said mould blocks are mated together as a pair at said faces to provide a mould having a series of equally spaced mould cavities and a channel, and in which said mould cavities each communicate with a respective one of a plural ity of branch runners in a hot runner manifold which is supplied with a molten material under pressure; accommodating a stringer tape in said channel with a beaded edge of the tape disposed in said mould cavities; feeding the molten material under pressure through said branch runners into said series of mould cavities: moving said mould, filled with the molten material, to another position in which the molten material solidifies to form a series of discrete fastener elements on said beaded tape edge corresponding to the series of mould cavities; and thereafter parting said pair of mould blocks.

2. A method as claimed in claim 1, further including the step of causing said upper and lower endless chains of mould blocks to move in synchronism intermittently.

3. A method as claimed in claim 2, in which the molten material is supplied to all the moulds in said first mentioned position.

4. A method as claimed in claim 2, in which the molten material is supplied only to selected moulds in said first-mentioned position so as to allow empty moulds to get past said first position.

5. A method as claimed in any preceding claim further including the step of providing a fixed rod extending in and through said mould cavities.

6. A method as claimed in any preceding claim wherein the stringer tape is inserted in said channel as the pair of mould blocks come to be mated together.

7. A method as claimed in any preceding claim wherein the pair of mould blocks come to be mated together at a position upstream of the position in which the mould cavities communicate with the branch runners.

8. An apparatus for producing a sliding clasp fastener stringer, comprising an upper endless chain of mould blocks and a lower endless chain of mould blocks, each mould having a mould face with a series of equally spaced half mould cavities and a half channel formed therein; means for moving a mould block of the upper chain and a mould block of the lower chain to a position in which said mould blocks are mated together as a pair at said faces to provide a mould having a series of equally spaced mould cavities and a channel for receiving a stringer tape with a beaded edge in said mould cavities; two pairs of spaced drive sprockets over which said upper and lower mould block chains run, respectively, said drive sprockets being rotatable intermittently; a hot runner manifold having a plurality of branch runners and arranged to be supplied with a molten material under pressure; means for holding said series of mould cavities in communication with said branch runners for receiving the molten material in said position; means for moving said mould, after being filled with the molten material, to another position in which the molten material solidifies to form a series of discrete fastener elements on said beaded tape edge corresponding to the series of mould cavities; and means for thereafter separating the pair of mould blocks.

9. An apparatus as claimed in claim 6, further including a fixed rod extending in and through said mould cavities.

10. An apparatus as claimed in claim 6, further including rollers held in rolling en

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. beaded tape edges 30, thereby preventing the beaded edges 30 from being deformed. To form discrete fastener elements 55 shown in Figures 5A and 5B, the upper and lower mould blocks 14, 16 have their mould cavity halves shaped to different configurations complementary to the upper and lower portions of the element 55. Furthermore, the fixed rods 31 are not necessary. A pair of series of discrete fastener elements 21 shown in Figure 6 can be injectionmoulded by feeding the molten material to all the moulds 20 which are successively transeferred to and intermittently stopped in the middle position 23. By supplying the molten material only to selected moulds 20 in the middle position 23 and allowing empty moulds 20 to go past the manifold 35 at suitable intervals, the injection-moulding apparatus 10 can produce a pair of fastener stringers shown in Figure 7 each having a series of discrete elements 21 on and along its beaded edge with element-free gaps 56 at spaced intervals. The element-free gap 56 can be changed in length by permitting empty moulds 20 to get successively past the manifold 35 as many as desired, or varying the length of the moulds 20, that is, altering the number of the mould cavities 32 in the moulds 20. An advantage resulting from the apparatus as illustrated and described is that the discrete fastener elements 21 thus formed are free of any excessive material such as sprues, gates, and runners which would be produced in existing injection-moulding apparatus and should be removed for finishing. WHAT WE CLAIM IS:-

1. A method of producing a sliding clasp fastener stringer comprising the steps of: providing an upper endless chain of mould blocks and a lower endless chain of mould blocks, each mould block having a mould face with a series of equally spaced half mould cavities and a half channel formed therein; transferring a mould block of the upper chain and a mould block of the lower chain into a position in which said mould blocks are mated together as a pair at said faces to provide a mould having a series of equally spaced mould cavities and a channel, and in which said mould cavities each communicate with a respective one of a plural ity of branch runners in a hot runner manifold which is supplied with a molten material under pressure; accommodating a stringer tape in said channel with a beaded edge of the tape disposed in said mould cavities; feeding the molten material under pressure through said branch runners into said series of mould cavities: moving said mould, filled with the molten material, to another position in which the molten material solidifies to form a series of discrete fastener elements on said beaded tape edge corresponding to the series of mould cavities; and thereafter parting said pair of mould blocks.

gagement with said upper and lower mould blocks in said first mentioned position to maintain these mould blocks tightly.

11. A method substantially as herein described with reference to and as illustrated in the accompanying drawings.

12. An apparatus substantially as herein described with reference to and as illustrated in the accompanying drawings.

13. A sliding clasp fastener stringer produced by a method as claimed in any one of claims 1 to 7 and 11 or by an apparatus as claimed in any one of claims 8, to 10 and 12.