US3854174A

US3854174A - Sliding clasp fastener

Info

Publication number: US3854174A
Application number: US00294323A
Authority: US
Inventors: T Yoshida
Original assignee: Yoshida Kogyo KK
Current assignee: YKK Corp
Priority date: 1971-10-02
Filing date: 1972-10-02
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17
Also published as: FR2154793A1; NL7213319A; FR2154793B1; GB1385998A; DE2247854A1

Abstract

A sliding clasp fastener is disclosed which comprises a pair of opposed carrier tapes each carrying along one and the same longitudinal edge a row of fastener elements interengageable to bring the tapes together in closed disposition by the agency of a slider. The elements are formed from a continuous filament material into a spring coil having a coupling head, upper and lower arms and a base. A reinforcing cord is inserted through the coil element row and intimately contacted therewith so as to prevent their relative movements during normal closing and opening operations of the fastener.

Description

[ Dec. 17, 1974 SLIDING CLASP FASTENER [751 Inventor:

[73] Assignee: Yoshida Kogyo Kabushiki Kaisha,

Tokyo, Japan [22] Filed: Oct. 2, 1972 [21] Appl. No.2 294,323

Tadahiro Yoshida, Fujisawa, Japan [30] Foreign Application Priority Data 1,529,317 France 24/205.l C 1,940,734 2/1971 Germany 24/205.l C 488,423 5/1970 Switzerland 24/205.l C

Primary ExaminerBernard A. Gelak 57] ABSTRACT A sliding clasp fastener is disclosed which comprisesa pair of opposed carrier tapes each carrying along one Oct. 2, 1971 Japan 46-90376 and the same longitudinal edge a row of fastener elements interengageable to bring the-tapes together in U.S. Cl- C, C closed disposition the agency of a slider The ele- [5 i Il'lt. ments are formed from a continuous filament material Field Of Search C, C, into a pring coil having a coupling head, upper and 24/2 C lower arms and a base. A reinforcing cord is inserted through the coil element row and intimately contacted [56] References Cited therewith so as to prevent their relative movements UNITED STATES PATENTS during normal closing and opening operations of the 3.189.964 6/1965 Galonska 24/205.l6 c fastener- FORElGN PATENTS OR APPLICATIONS 3 Claims, 4 Drawing Figures 1,253,944 11/1967 Qermany 24/205.l6 C

1 1 Av r r r III i 17 I PAIENI 3.854.174

SHEET 2 OF 2 F is. 3

F I G. 4

SLIDING CLASP FASTENER This invention relates to sliding clasp fasteners, more particularly to a sliding clasp fastener of the type which has a row of helically wound spring coil elements secured onto a longitudinal edge of a stringer tape.

Generally, the term coil element taken as an individual piece substantially comprises a coupling head portion, two arm portions and a base portion merging into an adjacent coil element. It is important to maintain constant an element-to-element spacing or pitch in its row so as to obtain stable and firm coupling engagement of the elements on the fastener tape. Various attempts have been made to this end. One prior art example is found in a fastener which has a row of coil elements each having a base portion spaced apart from adjacent one and sewn along one and the same longitudinal marginal edge of a carrier tape together with a stiffening cord inserted through the element row. This type of fastener has suffered from the disadvantage that the elements are prone to shift out of position relative to the stiffening cord, with the result that the pitch of elements in the row is distrubed and the strength of their coupling engagement is reduced to cause a breakage in the fastener chain.

Another prior art fastener has been proposed which employs a stiffening or reinforcing cord having grooves arranged to register with the base portions of coil elements, so that the elements are secured in place with their base portions alone anchored in the grooves by means of clamping threads wound in a direction reverse-to the winding of the coil of elements. Such fastener has been found defective for the purpose of applying a row of coil elements to one and the same edge of a carrier tape. This is because the reinforcing cord becomes stiff and hard under the influence of clamping threads, rendering it difficult to pass a sewing needle. Since the elements are secured in place only at their base portion, their positional stability and coupling strength are not satisfactory. Furthermore, the operation of winding clamping threads about the elements is tedious and time-consuming, and the threads are susceptible to wear in abrasive contact with aslider.

Whereas, it is the primary object of the present invention to provide an improved sliding clasp fastener of this character which will eliminate the foregoing disadvantages of the prior art.

It is a more specific object of the invention to provide improvements in a sliding clasp fastener whereby the pitch of elements in a row is maintained constant and the strength of coupling engagement of elements is increased.

These objects and features of the invention will appear clear from the following description taken withreference to the accompanying drawings in which:

FIG. 1 is a plan view on enlarged scale of an important part of a sliding clasp fastener embodying the invention;

FIG. 2 is a side view of the same;

FIG. 3 is a cross-sectional view taken on the line III- III of FIG. 1; and

FIG. 4 is a cross-sectional view of an important part of another embodiment.

According to the invention, there is provided a sliding clasp fastener which comprises a pair of opposed carrier tapes, a row of fastener elements mounted on one and the same longitudinal edge of each of said carrier tapes, said elements being formed from a continuous filament into a helically wound spring coil which has a coupling head, upper and lower arms and a base, adjacent bases of said elements being spaced a predetermined pitch apart, a reinforcing cord inserted longitudinally through said row of elements with each of said arms and base partly embedded in the periphery of said cord, and sewing stitches securing said row of elements together with said cord into position on said carrier tape.

Referring now to the drawings and FIG. 1 in particular there is shown a sliding clasp fastener 10 having a pair of opposed carrier tapes 11 each carrying along its one longitudinal edge a row of fastener elements E which are made usually of a continuous plastic filament formed into a helically wound spring coil. Each individual coil element e consists of a coupling head 12, an upper arm 13, a lower arm 14 and a base 15. The elements e in their row E are mounted on the respective carrier tape 11 with their base portions 15 spaced a predetermined pitch from adjacent base portions, as shown. The individual coil element e has an elongate square cross-section as seen in FIG. 3. There is provided a reinforcing cord 16 made of a single twisted thermoplastic material such as polyamide, polyethylene and the like for aligning the row of elements E and holding the individual elements e in uniformly spacedapart relation. In practice of one aspect of the invention, the cord 16 is inserted longitudinally through the row of elements E and urged into intimate pressure contact with the inner walls of the upper and

lower arms

13, 14 and bases 15, respectively of the individual coil elements e during the formation of the latter elements from a starting plastic filament. The element row E having the cord 16 thus embraced therein is secured along one and the same longitudinal edge of the tape 11 by means of sewing stitches 17 in the used manner and thereafter heat-treated so as to permit part of each of the upper and

lower arms

13, 14 and base 15 to be come affixed to the periphery of the cord 16. Preferably, the elements e of this configuration should be provided with notches or recesses 18 in the upper arms 13 for retaining the sewn stitches 17 against movement relative to the elements e. According to another aspect of the invention, there may be provided peripheral grooves 19 in the cord 16 at positions corresponding to the pitch of elements e so that the inner walls of upper and

lower arms

13, 14 and base 15 are partly embedded in the grooves 19 with results similar to the above heat-treating procedure.

Turning to FIG. 4 there is shown another sliding clasp fastener which is substantially identical with the fastener already described and shown in FIGS. 1 3, only with the exception that the element 2 has an eggshaped cross-section. The advantage of this embodiment is that the notches 18 referred to above can be dispensed with because the sewing stitches 17 due to the peculiar configuration of the elements e are urged toward the base portions 15 of the elements and thus prevented from shifting out of position under normal operating conditions.

Having thus described the invention, it will be apparent to those skilled in the art that various changes and modifications may be made in the specific form and construction illustrated, without departing from the scope of the appended claims.

What is claimed is:

1. In a sliding clasp fastener having a pair of opposed stringer tapes and rows of coupling elements mounted on respective stringer tapes, said coupling elements being formed as parts on a continuous filament helical coil, each element having a coupling head, upper and lower arm portions and a base portion, the improvement which comprises a reinforcing cord extending longitudinally through the coil defining each row of coupling elements, said reinforcing cord having a heli cal groove disposed for engagement with the coupling elements coil to embed portions thereof in said groove to maintain a pitch spacing among the coupling ele ments equivalent to the helical pitch of said groove.

2. The improvement according to claim 1 wherein said groove embeds the base portion and parts of the upper and lower arm portions of said coupling elements.

3. The improvement according to claim 1 including means defining notches in the upper arm portions of said coupling elements to receive and retain sewing stitches which secure the coupling elements to the stringer tapes.

Claims

1. In a sliding clasp fastener having a pair of opposed stringer taPes and rows of coupling elements mounted on respective stringer tapes, said coupling elements being formed as parts on a continuous filament helical coil, each element having a coupling head, upper and lower arm portions and a base portion, the improvement which comprises a reinforcing cord extending longitudinally through the coil defining each row of coupling elements, said reinforcing cord having a helical groove disposed for engagement with the coupling elements coil to embed portions thereof in said groove to maintain a pitch spacing among the coupling elements equivalent to the helical pitch of said groove.