US2581604A - Slide fastener - Google Patents

Description

B. C. ROEHRL SLIDE FASTENER Jan. 8, 1952 2 SHEETS-SHEET 1 Filed April 1'7, 1946 Patented Jan. 8, 1952 SLIDE FASTENER Bruno C. Roehrl, Erie, Pa.,

assignor to National Organ Supply Company, Erie, Pa., a corporation of Pennsylvania Application April 17, 1946, Serial No. 662,706

4 Claims. 1

This invention is intended to provide a slide fastener having mating strips of flexible plastic, such as polyethylene, vinylite, etc. have continuous locking shoulders which cannot be jammed by threads and which make a dust tight seal. Because all of the surfaces of the fastener are smooth, it is easy to keep clean. Further objects and advantages appear in the specification and claims.

In the drawings, Fig. 1 is a top view of the fastener; Figs. 2 to 6 are sections on correspondingly numbered lines in Fig. 1; Fig. 7 is a top view of the slide; Fig. 8 is a section on line 8--8 of the slide; and Fig. 9 is an end view of the slide.

Referring to the drawing, I and 2 indicate the mating strips comprising the slide fastener. These strips may be extruded from flexible thermoplastics of the class known as elastomers, such as polyethylene, or vinylite. These materials are particularly adapted to this fastener since they are substantially non-stretchable, non-corrosive,

have a low coeflicient of friction, and come in a wide variety of colors.

At the outer edge of each of the strips is a tongue 3 to which is fastened a tape 4 by which the strips can be sewn as in the conventional slide fastener. The edges 5 of the tape are folded over the upper and lower surfaces of the tongue, being located by shoulders 6 and fastened to the tongue either by an adhesive or by pressing the tape against the tongue while it is heated above the Softening temperature. The strip I is extruded in a single piece. The strip 2 is extruded in upper and lower halves which are cemented together along a surface I at the outer edge, leaving the inner ends 8 and 9 free to flex transversely to the strip.

In the closed position of the fastener. the inner end III of the strip I is received between the inner ends 8 and 9 of the strip 2. On the outer face of the inner edge of the strip I is a rib or bead II having an undercut locking shoulder I 2 which cooperates with an undercut locking shoulder I3 on a rib or bead It at the inner edge of the end 8 of the strip 2. Because the looking shoulders I2 and I3 are continuous and undercut, the shoulders form a substantially airtight seal and effectively resist separation of the fastener even though the ribs II and I4 may flex slightly. on the under side of the inner edge of the strip I' is a rounded rib or bead I5 which in the closed position of the fastener cooperates with a rib or bead IS on the inner edge of the end 8 of the strip 2 and identical with the rib I4. The ribs I5 and I6 are not intended to lock the fas- The stri psedges of the strips.

2 tener in the closed position, but merely to locate the inner edges of the fastener.

On the outer surface of the fastener is a slide ll which bridges the joint between the inner The outer ends of the slide have dove-tail grooves II which slide on dovetail ribs I9 on the outer surface'of the respective strips. As indicated in Fig. 1, the grooves I8 are curved along the length of the slide. At the line 6-6 in Fig. 1, the spacing of the grooves is equal to the normal separation of the ribs I9 in the closed position of the fastener. At the line 5-5 in Fig. 1. the grooves [8 are closer together than in the line 6--6, thereby forcing the strips edgewise toward each other so that the undercut locking shoulders I2 and I3 are clear. In this position the fastener can be unlocked by lifting 'the end I of the strip 2. This lifting is accomplished by an inclined wedge or cam 20 which rides on the outer face of the strip I and cooperates with the surface 2I on the under side of the rib I I. At the highest point of the wedge 20, the inner end 8 of the strip 2 is lifted to the position shown in Fig. 4. In Fig. 4 the strip 2 has been started to move edgewise away from the strip I by contact with the tapered section 22 on the inner wall of the slide. The tapered section 22 reaches its maximum thickness shortly before the line 2-2 in Fig. 1, at which point the locking shoulders of the fastener are completely separated, as indicated in Fig. 2. The separating or unlocking movement of the strips is slightly resisted by the rounded rib I5 on the under side of the strip I. but the resistance offered is lnsumcient to interfere with the operation of the slide. The locking and unlocking of the fastener do not injure or stress the locking surfaces I2 and I3 since these surfaces are out of contact during both the locking and unlocking movement of the slide. This prevents rounding of the locking shoulders which would make the locking of the fastener less secure.

It will be noted that the strips of the fastener are flexed to some extent at all points between the ends of the slide I"I. When the fastener is made of thermo-plastic material which has a ten dency to cold flow or set, there is a possibility that the portion of the strips between the ends of the slide might take a permanent set which would interfere with the operation of the fastener. This is of minor importance at points intermediate the ends of the fastener since the slide will rarely be left for any appi eciable length of time in a position corresponding to a partly opened and partly closed position of the fastener.

The slide is, however,

likely to be left at the extreme ends of the fastener, at which points the parts of the strip within the slide would be flexed to the positions illustrated in Figs. 2 to 6. The flexing of the fastener to the position indicated in Fig. is not serious since the ordinary stresses on the fastener will tend to move the locking shoulders l2 and I3 into contact and thereby overcome any set due to the edgewise curvature of the strips.

The flexing indicated in Figs. 3 and 4 is more serious since it separates or spreads the ends 8 and 9 of the strip 2 and thereby decreases the resilience with which the ends grip the inner ends of the strip I. This flexing can be eliminated by tapering the projecting portions of the ribs 1 I, I4, I5 and Hi to the point indicated by dotted lines 23, 24, 25 and 26. This tapering is gradual so as not to provide any abrupt surfaces which would interfere with the operation of the slide. It can be accomplished by planing the outer surfaces of the ribs at the extreme ends of the fastener.

While 'it is true that the removal of the ribs removes the locking shoulders, the locking shoulders are not necessary for the part of the fastener between the ends of the slide since the slide through the action of the dove-tail grooves and ribs 18 and I9 holds the fastener together.

In the assembly of the fastener, the strips I and 2 are assembled in the closed position, and one end of the strips is permanently fastened either by an adhesive or by heating to a softening temperature and pressing the ends together. The slide is then slid onto the other end of the strips, the dove-tail ribs l9 being received in the dovetail grooves l8. A stop may then be added to the extreme end of one of the strips to prevent removal of the slide.

' shoulder cooperating with the first shoulder and the inner of which provides a shoulder in nonlocking cooperating with the second shoulder, ribs on the outer faces of the respective strips having undercut grooves in the outer edges, a slide extending across the outer faces of the strips with ends received in the grooves, said ends converging to move the strips edgewise toward each other to move the undercut locking shoulders clear of each other and then diverging, and a cam on the slide having a portion riding on the outer face of the first strip and extending between the outer face of the first strip and the cooperating side of the mating strip for camming the locking shoulders apart in the portion of the strips where the locking shoulders are clear of each other.

2. In a slide fastener, a flexible non-stretchable strip having along one face only a rib defining an undercut locking shoulder, a mating flexible non-stretchable strip having a channel loosely receiving the first strip with sides resiliently engaging opposite faces thereof, one side having an undercut locking shoulder cooperating with the unlocked, and said first cam means having a portion cooperating with the strips beyond the point at which the shoulders are unlocked for camming the strips edgewise apart to separate the strips.

3. In a slide fastener, a flexible non-stretchable strip having on its outer face only a rib defining an undercut locking shoulder, a mating flexible non-stretchable strip having a channel loosely receiving the first strip with sides resiliently engaging opposite faces thereof, the outer side of the channel having an undercut locking shoulder cooperating with the first shoulder to prevent edgewise separation of the strips, dovetail ribs on the outer faces of the strips, a slide having grooves receiving the dovetail ribs, the grooves converging from the locked and of the slide to move the strips edgewise until the shoulders are clear and then diverging toward the unlocked end of the slide, and a cam on' the slide acting between the outer face of the first strip and the outer channel side to wedge apart the portions of the shoulders which are clear.

4. In a slide fastener of strips of flexible nonstretchable thermoplastic of the class known as elastomers and characterized by a low coefllcient of friction, a flexible strip having along its outer face only a rib defining an undercut locking shoulder, a mating flexible strip having a channel loosely receiving the first strip with sides resiliently engaging inner and outer faces thereof, the outer channel side having an undercut looking shoulder cooperating with the first shoulder to prevent edgewise separation of the strips, a slide for opening and closing the fastener on the outer face of the strips having ends slidably anchored on the respective strips, said ends converging to move the strips edgewise toward each other to move the undercut locking shoulders clear of each other and then diverging, and a cam on the slide riding on the outer face of the first strip extending only-between the outer face of the first strip and the outer channel side to cam' the shoulders apart in the portion of the strips where the locking shoulders are ,clear of each other.

BRUNO C. ROEHRL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

Images