Lockable slide fastener slider

Abstract: A lockable slide fastener (10) comprises an upper wing (11) and a lower wing (12) defining therebetween a guide channel (14) for the passage of fastener coupling elements (E), a pull tab (20) pivotably mounted on the upper wing (11) and a locking member (26) having a locking prong (30) movable into and away from the guide channel (14). A resilient means (31, 31a, 31b, 31c) is provided in operative relation to the pull tab (20) for urging the latter to lie substantially flat against the upper wing (11).

Description: This invention relates to a lockable slider manipulated to open and close a slide fastener. There have been proposed numerous slide fastener sliders having means locking the slider against unintentional displacement. One such prior locking slider is disclosed in US-A-3 522 638 in which a locking pawl having a tooth is brought into and out of engagement with some of the coupling elements of the fastener in a slider channel by moving a handle flap (pull tab) pivotably in one or the other direction with its cam portion borne against the upper surface of the flap. A compression spring is adapted to normally hold the flap in horizontal flat position. A difficulty of this prior device is that if for some reason the tooth of the locking pawl fails to engage in the space between adjacent coupling elements as required but instead rides over the upper surfaces of the coupling elements, the locking pawl tends to somewhat press the spring so that the resilient force of the spring is not transmitted to the handle flap, leaving the latter free to wobble itself or hook on the garment or some other objects, resulting in damage to the handle flap or the hooked objects. With the foregoing difficulties of the prior art in view, the present invention seeks to provide a lockable slide fastener slider incorporating a locking means which will ensure a form lock of the slider in any longitudinal position of the slide fastener whether it be on a coupling element, a top end stop, a bottom end stop, or an end separator and which will further ensure retention of a pull tab in flipped flat position relative to the slider body when the slider is locked. According to the invention, there is provided a lockable slide fastener slider which comprises: a slider body including an upper wing and a lower wing joined at one of their respective ends by a neck so as to define therebetween a guide channel for the passage of a pair of rows of coupling elements, a pull tab pivotably connected through its pintle to the upper wing and has a cam means, a locking member pivotably supported on the slider body and including a locking prong moveable into and away from the guide channel and resiliently urging the pull tab to flip down against the upper wing, characterised in that a further resilient means is provided to independently bias only the pull tab toward the upper wing of the slider. The above and other advantages and features of the invention will become manifest to one skilled in the art from reading the following detailed description with reference to the accompanying drawings. Like reference numerals refer to like or corresponding parts throughout the several views. Figure 1 is a side elevational, partly sectional, view of a slider constructed in accordance with a first embodiment of the invention; Figure 2 is a partly sectional, plan view of the same; Figure 3 is a longitudinal cross-sectional view of a portion of the same, showing a pull tab in flipped flat position; Figure 4 is a view similar to Figure 3 but showing the pull tab in a lifted position; Figure 5 is a side elevational, partly sectional, view of a slider constructed with a second embodiment of the invention; Figure 6 is a partly sectional, plan view of the same; and Figure 7 is a longitudinal cross-sectional view of a portion of the same, showing a pull tab in a lifted position. Referring to the drawings and firstly Figures 1 - 4 inclusive, there is shown a lockable slider 10 provided in accordance with a first preferred embodiment of the invention. The slider 10 comprises a slider body including an upper wing member 11 and a lower wing member 12 joined at one of their respective ends by a wedge-shaped neck 13 at a front end of the slider body so as to define therebetween a substantially Y-shaped guide channel 14 for the passage of a pair of rows of coupling elements E on respective stringer tapes as is well known. The upper wing 11 has an aperture 15 communicating with the guide channel 14 for allowing the passage therethrough of a locking prong later described into and out of the channel 14 to engage and disengage the coupling elements E. The upper wing 11 has raised confronting side flanges 42 defining therebetween a chamber for receiving a pull tab later described. The slider 10 is of a type somewhat similar to an automatic lock slider disclosed in US-A-4 391 022 to the same assignee of the present application in that it includes a locking member 26 in the form of a polygonal leaf spring. The locking member 26 has a vertically elongated one end 26' secured in place in the well 24, a generally U-shaped engaging portion 26'' and a locking prong 30 extending downwardly therefrom. The pull tab 20 has a pintle 40 about which it is pivotable and a first cam 41 formed centrally on the pintle 40 for engaging the U-shaped portion 26'' of the locking member 26. Lifting the pull tab 20 from its solid line position to its phantom line position, as shown in Figure 1, causes the locking prong 30 to disengage the coupling elements E and ascend away from the guide channel 14 to its phantom line position against the tension of the locking member 26 per se. Releasing or flipping down the pull tab 20 causes the locking prong 30 to descend under the influence of the tension of the locking member 26 and engages normally in between adjacent coupling elements E thereby locking the slider 10 against unintentional movement, in which position the pull tab 20 is held flat against the upper surface of the upper wing 11 as shown in Figure 1. However, the locking prong 30 is liable to ride over and rest directly against the coupling elements E instead of entering therebetween during its descending movement with the result that the pull tab 20 is held apart from the upper wing 11 and hence tends to idle. This problem is overcome by the provision of a second resilient means 31 in the form of a plain leaf spring according to the first embodiment of the invention. As better shown in Figures 1 and 2, this resilient means 31 provides a torsional moment compensating for the lack of spring force of the locking means 26 and acts upon the pull tab 20 to urge the latter to lie flat against the upper wing 11 of the slider 10 as shown in Figure 1. The resilient means 31 comprises a pair of elongated leaf springs 31a, 31b accommodated in a casing 42 and laterally spaced on opposite sides of the upper wing 11 and extending in overlying relation to the locking member 26. Both ends of each of the leaf springs 31a, 31b are loosely fitted in recesses 43 formed between the casing 42 and the upper wing 11 as better shown in Figures 3 and 4, so that the leaf springs 31a, 31b can flex vertically. The pull tab 20 is provided with a pair of downwardly oriented second cams 44a, 44b extending from opposite ends of its pintle 40 and registering in position with the respective leaf springs 31a, 31b which normally act upon the respective cams 44a, 44b so that the pull tab 20 is urged to lie flat against the upper surface of the upper wing 11 of the slider body. Figures 5 - 7 inclusive show a lockable slider 10 according to a second embodiment of the invention in which the resilient means 31 comprises a leaf spring 31c of rectangular frame form as better shown in Figure 6. The leaf spring 31c is flexibly supported in a recessed surface portion 50 of the upper wing 11 and disposed in underlying relation to the locking member 26 in contrast to the first embodiment as better shown in Figure 7. The pull tab 20 has a first cam 51 formed centrally on a pintle 52 for engaging a U-shaped portion 26'' of the locking member 26 which is substantially similar in construction to that which appears in the first embodiment. The first cam 51 is normally urged downwardly by the locking member 26 in the direction of the arrow D as shown in Figure 5. A pair of upwardly oriented second cams 53a, 53b extend from opposite ends of the pintle 52 in overlying relation to the leaf spring 31c which urges the second cams 53a, 53b normally upwardly in the direction of the arrow F as shown in Figure 5. When flipping down the pull tab 20 from the unlocked position of the slider 10 shown in Figure 7 to the locked position in solid line of Figure 5, the pull tab 20 sometimes fails to lie horizontally flat against the upper wing 11 due to the locking prong 30 riding over and resting directly against the coupling elements E as already described. This problem is solved by the provision of the resilient means 31 or leaf spring 31c which cooperates with the second cams 53a, 53b of the pull tab 20 in retaining the latter in proper flipped flat position relative to the upper wing 11 of the slider body.

Claims: A lockable slide fastener slider (10) which comprises: a slider body including an upper wing (11) and a lower wing (12) joined at one of their respective ends by a neck (13) so as to define therebetween a guide channel (14) for the passage of a pair of rows of coupling elements (E); a pull tab (20) pivotably connected through its pintle (40, 52) to the upper wing (11) and having a cam means (41, 44a, 44b, 51, 53a, 53b); a locking member (26) pivotably supported on the slider body and including a locking prong (30) movable into and away from the guide channel (14) and resiliently urging the pull tab (20) to flip down against the upper wing (11); characterised in that a further resilient means (31, 31a, 31b, 31c) is provided to independently bias only the pull tab (20) toward the upper wing (11) of the slider. The lockable slide fastener slider (10) of claim 1, wherein said further resilient means (31, 31a, 31b, 31c) is a leaf spring. The lockable slide fastener slider (10) of claim 1 or 2, wherein the resilient means comprises a pair of leaf springs (31a, 31b) laterally spaced on opposite sides of the upper wing (11) and extending in overlying relation to the locking member (26). The lockable slide fastener slider (10) of claim 2 or 3, characterised in that the resilient means (31) comprises a leaf spring (31c) of rectangular frame form and disposed in underlying relation to the locking member (26). The lockable slide fastener slider (10) according to claim 1, wherein the resilient means (31) is a torsion spring wrapped around the pintle (40, 52) and received in an oblong aperture in the pull tab (20) and is convergent toward a rear end of the pull tab (20) to provide an upwardly slanted bottom wall for receiving thereon one end extension of a torsion spring.

Inventors: ISHII SUSUMU, ODA KIYOSHI, ISHII, SUSUMU, ODA, KIYOSHI
Applicants: YKK CORP, YKK CORPORATION
Application year: 1991
Main classification: A44B19
IPC codes: A44B19