JPH0143955B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a fastener assembly;
More specifically, but not exclusively,
The present invention relates to a method of manufacturing a fastener assembly that can be dispensed by a product tagging and attachment machine.

BACKGROUND OF THE INVENTION Many different types of fasteners are used for product tagging and for many attachments.

These fasteners can be made by, for example, molding.
Fastener assemblies are manufactured, each fastener having a narrow filament interconnecting the head and crossbar and being joined to a common runner bar by a neck. These fasteners can be dispensed using a gun-type dispenser such as that described in US Pat. No. 3,103,666.

It has been discovered that these fasteners can be significantly and unexpectedly improved by stretching, as described in U.S. Pat. No. 3,444,597, which also describes simultaneously stretching individual fastener assemblies. ing. Various methods of making stretch fasteners are described in US Pat. Nos. 3,380,122, 3,444,597 and 3,445,589. These specifications state that the fastener assembly is molded with a slight taper in the filaments to ensure that this stretching substantially extends to the filament-to-crossbar joint. has been done. Although the manufacturing methods described in these specifications provide suitable fasteners, the manufacture of these fasteners requires considerable time, e.g., cycle time between molding and completion of stretching. Requires. Additionally, these methods are particularly suited to easily stretchable crystalline materials such as nylon;
These methods are not suitable for relatively hard crystalline materials such as polypropylene. Another difficulty encountered with materials such as polypropylene is that the crossbar tends to be pulled forward at the filament-to-crossbar junction.

Furthermore, U.S. Patent No. 4183894 and Japanese Patent Publication No. 1983-
No. 42,827 also discloses a method of manufacturing fastener assemblies by heating and stretching. However, in all of these methods, the crossbar is not shielded from the heat source.

An important problem in the manufacturing method of such fastener assemblies is that the crossbars are deformed during the stretching process, and when the finished fasteners are dispensed by the distributor, the crossbars become trapped inside the distributor. The problem is that it becomes difficult to dispense the fastner.

(Means for solving the problem) According to the present invention, in order to solve this problem,
An assembly comprising a plurality of fasteners and a common member, each of the plurality of fasteners having a central filament, a crossbar located at one end of the filament, and a crossbar at the other end of the filament. forming an assembly with a head located at the crossbar, the common member connecting the fasteners at the crossbar side ends, and then molding the assembly with the crossbar shielded from a heat source. While heating the filaments, the distance between the gripping jaws is adjusted so that the joint points between the filaments of the plurality of fasteners and the crossbar are heated at the same time. Unfold and stretch the filament along its length.

A method of manufacturing a fastener assembly is provided, characterized in that:

Undesired heating effects on the crossbars of the individual fasteners are prevented by providing shields.

Preferably, at least one stretching element is cooled and has a jaw opening for the associated member which is thinner than the smallest diameter of the filament to be stretched.

Details of some preferred features include:

The assembly can be fed into the enlarger using clamping jaws that grip both ends of the fastener. The clamping jaws are then separated to tension the filament, and the filament is simultaneously subjected to temperature-controlled heating in conjunction with the shielded crossbar. The clamping jaws are then separated for stretching, followed by relaxation and the stretched assembly can be removed from the stretching machine.

The shield is preferably part of the retracting jaw, but may be a separate member.

Fasteners can be manufactured in a mold using separable parts, and the filament is subjected to temperature-controlled heating when the mold parts are separated.

The temperature-controlled heating is preferably carried out by an infrared radiator, which directs its heating effect to the joint of the filament with the end piece.

Preferably, each of the filaments has a taper over its length to ensure that the stretching extends to the junction with the crossbar. However, the filament may be of other shapes, including generally cylindrical shapes.

The fastener is preferably made of a crystalline material, the molecules of which are reoriented by stretching, and preferably selected from nylon, polyethylene, polypropylene and polyester and acetone resins.

Embodiments Referring now to the drawings, FIG. 1A illustrates a fastener assembly 10 including individual fasteners 20-1 through 20-n, in which individual fasteners, e.g. 1 fastner 20
-1 includes a crossbar 20c connected to a head 20h by a filament 20f.
The fasteners 20-1 to 20-n are collectively joined to the runner bar 11 constituting a common member by individual necks 20n extending from the cross bar 20c.

The filaments 20f of the fasteners 20-1 to 20-n appear cylindrical over the main part of their length, starting from the crossbar 20c, but
These typically have a slightly tapered area. This is illustrated in the enlarged section of the individual fastener 20-1 shown in FIG. 1B. The fastener 20-1 illustrated in FIG. 1B has a minimum diameter of about 5.59 mm at a position A, which is about 16.76 mm from the joint 20j of the fastener 20-1 with the crossbar 20c. The diameter of the filament 20f gradually increases to 6.10 mm at position B, then to 6.35 mm at position C, and further to 6.60 mm at position D.

The fastener assembly shown in FIGS. 1A and 1B is similar to the machine 3 of the construction shown in FIG. 2A.
Stretched at 0. The machine 30 includes an outer gripping jaw 31, an inner gripping jaw 32, and a thermal mask or shield 33. The outer clamping jaws have an inner region 3 that accommodates one end of the product to be stretched.
1r, and the inner clamping jaws 32 have a similar internal area 32r for the other end of the product.

In the case of an unstretched fastener assembly, only its first member 20-1 is shown in FIG. 2B, the fastener head 20h is attached to the outer clamping jaws 3.
1 and the runner bar is within the internal region 32r of the inner clamping jaw 32.

In FIG. 2A, outer clamping jaw 31 has a groove 31c that accommodates a portion of filament 20f' near head 20h'.

In the particular embodiment of FIG. 2A, the inner clamping jaws 3
2 is fixed, and the distance between the outer clamping jaws 31 and the inner clamping jaws 32 can be increased by, for example, a fluid mechanism.

In FIG. 2A, only one half of the machine 30 is shown, and a similar half is used for simultaneous stretching of other sets of green material, with connectors constituted by gating sprues. 22 with clamping jaws 31 and 32
The set is joined within the set.

When joined by a degatable connector or sprue 22, for example, the illustrated fastener 20-1' is positioned between the clamping jaws 31 and 32, and the fastener assembly is fed into the machine 30. After that, for example, the clamping jaws 31 are operated to tighten the slack in the fastener, and from the initial position 31a to the intermediate position 31b.
Move to.

In the general case, stretching is carried out by moving the outer clamping jaws 31 to the final position 31f. A temperature controlled heat source device 40 is used to promote and facilitate stretching of stretch resistant crystallized plastics such as polypropylene.

In the case of FIG. 2A, a thermal mask or shield 33
is attached to the inner clamping jaw 32.

Temperature-controlled heat source device 40 includes a holder 41 and a quartz infrared lamp 42, described in detail below. The heat from this lamp 42 constituting the heat source is first transferred to the outer clamping jaws 31.
is added when is in its initial position 31a. This heating action is continuously applied until the clamping jaws 31 are moved to their final position 31f, thereby creating a stretched fastener. Second
As is clear from the arrangement shown in Figure A, the filaments are heated such that the joint points between the filaments of the plurality of fasteners and the crossbar are heated simultaneously. After completing the stretching, the clamping jaws 31
are relaxed to allow removal of the stretched fastener from machine 30. shield 33
is fixed to the clamping jaws 32, and the crossbar 2
0c' from the adverse effects of heating and, in particular, the crossbar from being adversely affected during the stretching operation.

Since the groove 32c of the inner clamping jaw 32 shields the fastener neck 20n', the clamping jaw 3
The gripping action of 2 is against the runner bar 11'.
The shielding of the net 20n' prevents it from being inadvertently stretched, while the gripping of the runner bar 11' prevents inadvertent damage to the crossbar 20c'.

In the modified apparatus shown in FIG. 2B,
Lamp 42 is connected to adjustable end fitting 4 to directly heat the desired portion of filament 20f'.
It is positioned at number 3. And shield 3
3' is provided to shield the crossbar from the lamp 42, which is a heat source.

End fitting 43 is adjustable in any standard manner to control the direction of infrared radiation from lamp 42.

Lamp 4 shown in Figures 2A and 2B
A perspective view of part 2 is shown in FIG. A quartz tube 42g encloses a resistance coil 42c having terminals 42t-1 and 42t-2. coil 4
Internal reflector 4 that directs infrared rays at right angles above 2c
There is 2r. Ramp 42 is located in New York, USA.
11415, Kew Garden, 125-10 Queen Boulevard,
Hugo N.Cahnman
A known infrared lamp heating device available from Assoc Istes, Inc.) may be used. This device has an infrared radiation range of 2 to 5 microns and can be used at temperatures between 315°C and 1100°C.

The temperature of the lamp 42 and the time during which the fastener is subjected to the heating effect are optimized as desired, so that the heating effect and the temperature effect are below the value at which the fastener will cause dissolution. That is, the product HT of the amount of heat per unit time H and the exposure time T is below the solubility limit of the fastener.

The internal reflector 42r of the heat source device 40 allows approximately 85% of the radiant energy to be directed toward the product.

FIG. 4 shows a fastener assembly 50, each of which is elongated and associated with two cylindrical filaments 50-1 and crossbars 50c-1 and 50c-2 at each end. Runner bars 11-1 and 1
1-2. Either runner bar 11-1 or 11-2 can be used to feed with a gun-type distributor, such as that described in the above-mentioned US Pat. No. 3,103,666. Other runner bar 11-2 or 11-1
provides strength to fastener assemblies 50 and facilitates their handling during stretching operations when temperature controlled heating is used. One of the runner bars can be removed by degating when the stretching operation is complete. It is clear that supplementary runner bars can be used with other types of fasteners and equipment to facilitate handling of stretching operations using temperature controlled heating.

Another type of blank that can be stretched as described above is shown in Figures 5A-5C. In FIG. 5A, the unstretched fastener 25 has the smallest diameter portion 25d of the filament 25f near the crossbar 25c. In FIG. 5B, fastener 26 has a substantially cylindrical filament 26f with a smallest diameter portion 26d at an intermediate position. In FIG. 5C, the minimum diameter 27d of the filament 27f of the fastener 27 has a decreasing taper 2
7t-1 (starting at crossbar 27c) and the forward taper 27t-2.

Filament 25f in FIGS. 5A and 5C,
When uniform heating is performed on 26f and 27f,
Stretching begins at the smallest diameter portions 25d, 26d and 27d and proceeds successively in the direction of the smallest. Therefore, in the case of FIG. 5C, the second taper 2
7t-2 has a higher shoulder than the first taper 27t-1, so the stretching is directed towards the joint 27j before any slight stretching occurs in the region of the forward taper 27t-2. It is done.

(Effects) According to the method for manufacturing a fastener assembly according to the present invention, with the crossbar shielded from the heat source,
While holding both ends of the fastener assembly by respective gripping jaws, the distance between the gripping jaws is adjusted while heating the plurality of fastener filaments so that the joints between the filaments of the fasteners and the crossbar are heated simultaneously. Unfold and stretch the filament along its length.

This can prevent the crossbar from deforming and can prevent the crossbar from becoming jammed in the distributor.

[Brief explanation of drawings]

FIG. 1A is a perspective view of the fastener assembly. FIG. 1B is an enlarged view of the individual fastener sections of the assembly of FIG. 1A. Figure 2A shows the first
Figure 1B is a plan view of the stretching machine used to manufacture the assembly shown in Figures A and 1B; FIG. 2B is a plan view of another enlarger. FIG. 3 is a perspective view of a lamp used in the machine shown in FIGS. 2A and 2B. FIG. 4 is a perspective view of another fastener assembly.
FIGS. 5A to 5C are perspective views of other fasteners before being stretched. 10... Fastener assembly, 11... Runner bar, 20-1 to 20-n... Fastener, 20c...
Crossbar, 20f...filament, 20h...head, 20n...net, 30...machine, 31...outer clamping jaw, 32...inner clamping jaw, 33...shield, 33'...shield, 40...heat source device, 42...
Lamp, 42r...internal reflector, 50...fastener assembly.

Claims (1)

[Scope of Claims] 1. An assembly consisting of a plurality of fasteners and a common member, each of the plurality of fasteners comprising:
a central filament, a crossbar located at one end of the filament, and a head located at the other end of the filament, the common member connecting the fasteners at the ends on the crossbar side. Then, with the crossbar shielded from a heat source, the filaments of the plurality of fasteners and the crossbar are clamped by respective clamping jaws at both ends of the assembly. A method for producing a fastener assembly, which comprises stretching the filament along its length by increasing the spacing between the clamping jaws while heating the filament, such that the joint points of the filaments are heated simultaneously with each other. 2. The method of manufacturing a fastener assembly according to claim 1, wherein each of the filaments is tapered at a portion thereof. 3. The assembly includes a plurality of pairs of fasteners connected head to head, and two common members connecting crossbars of each of the fasteners, or 2. A method for manufacturing a fastener assembly according to item 2. 4. The method for manufacturing a fastener assembly according to any one of claims 1 to 3, wherein the heating is performed by infrared rays. 5. Claims in which the assembly is fed to a stretching machine equipped with clamping jaws, the spacing between the clamping jaws is widened while the fasteners are heated, and the clamping jaws then release the fasteners. 1st
2. Method for manufacturing the fastener assembly described in Section 1. 6. The method of manufacturing a fastener assembly according to claim 5, wherein the clamping jaws are cooled by a fluid coolant. 7 Product of heat amount H per unit time and exposure time T
7. The method of manufacturing a fastener assembly according to claim 6, wherein HT is below the solubility limit of the fastener. 8 the assembly is molded in a mold with separable parts, and while the fastener is heated the spacing between the parts of the mold is widened so that the filament is A method of manufacturing a fastener assembly according to claim 1, wherein the fastener assembly is expanded. 9. A method of manufacturing a fastener assembly according to any one of claims 1 to 8, wherein the fastener is formed of a crystalline material. 10. The method of manufacturing a fastener assembly according to claim 9, wherein the material is selected from nylon, polyethylene, polypropylene, polyester, and acetone resin. 11. The method of claim 1, wherein the fastener is molded from polypropylene that is resistant to cold stretching. 12. The method of manufacturing a fastener assembly according to any one of claims 1 to 11, wherein at least one of the clamping jaws clamps a common member. 13 The clamping jaws clamping the common member,
13. The method of manufacturing a fastener assembly according to claim 12, wherein the fastener assembly is shielded from a heat source.