Watch Band Strap With Releasable End Connection

Abstract

A tubular element of elastic temporarily deformable, preferably thermoplastic material is bonded to the watch strap, for example by fusion if the watch strap is likewise of plastic material; the tubular element has a transverse slit so that, upon deformation of the tubular element in the region of the slit, the cross pin of a wrist watch case can be snapped through the slit into the hollow of the tube.

Description

The present invention relates to watch bands, and more particularly to the terminal end connections interconnecting wrist watch straps with the cross pins of wrist watches, and more especially to such watch straps made, themselves, of thermoplastic material.

Watch straps, regardless whether made of leather or man-made material, such as thermoplastic, require a connecting loop to interconnect the watch strap with the watch case. Such a loop is always necessary when the strap is to have two parts, which is the usual construction, particularly when the strap is to be used with smaller wrist watches. Leather straps are frequently so constructed that the strap has an extension which is looped about the cross pin of the watch, the end of the projection then being secured to the watch strap by means of a catch or a clamp, for example made of metal. Metal clamps must be so constructed that they cannot be seen from the top of the wrist watch strap; this requires a connection to the usually quite thin-enough layer of the strap. The projection must have a certain minimum length in order to provide the required strength, particularly under tension, which has the disadvantage that the shifting of the material may result in the region of the connection of the projection with the remainder of the strap, since the additional thickness of the projection material is added to the normal thickness of the watch strap. This is inconvenient to the wearer and detracts from the overall appearance.

The construction just described in connection with leather straps is hardly applicable to be used with thermoplastic material, since artificial, thermoplastic material has low resistance against tearing, while being more elastic than leather. Thus it is possible that the projection loop over the cross pin of the watch casing can slip out, or tear out of the metal clamps. Thermoplastic watch straps can be made to have a loop integral therewith, the watch then being secured to the strap by slipping a spring-loaded cross pin through the loop, and then securing the watch casing to the spring-loaded cross pin. Such connections are quite satisfactory; they cannot however, by used with watch cases in which the cross pin of the casing is integral with the remainder of the casing, a construction frequently used in very thin, and thus more costly watches. Any kind of watch strap which requires insertion of a spring-loaded pin cannot be used with such watch casings.

Watch straps have previously been proposed in which small metal interconnecting loops are used, hooking over the watch cross pin on the one hand, and being secured to the strap on the other. Such straps are subjected to substantial tension, and the strap material itself frequently must have a reenforcing insert made of metal. To obtain the necessary stability, the free leg of the hook must be comparatively long. A safety latch may be arranged in the region of the hook, in order to prevent inadvertent opening thereof, and loss of the watch. All this requires additional metal material, and introduces problems in manufacture and use, particularly since the watch strap material which partly surround the metal parts is subjected to excess wear by the metal, thus tending to be worn through.

It is an object of the present invention to provide a terminal connection for watch straps of two parts, which is easy to manufacture, provides a safe and stress-resistant connection with the watch casing and is additionally of pleasing appearance, while being suitable for use with watches having an integral cross pin.

SUBJECT MATTER OF THE PRESENT INVENTION

Briefly, a small tubular element having a longitudinal slit is secured to the watch strap material. The tubular element is made of temporarily deformable elastic material, for example a thermoplastic which can be bonded to the thermoplastic watch strap material, by adhesion, by fusion or the like. If the watch strap includes reenforcing inserts, for example of textile material, then such reenforcing inserts can additionally be secured to the tubular element. The tubular element itself may be made of nylon, a polyester resin, or the like. The strap is secured to the cross pin of a watch by deforming the tubular element in the region of the slit, and snapping it over the cross pin.

The structure, organization, and operation of the invention will now be described more specifically with reference to the accompanying drawings, wherein:

FIG. 1 is a side view of a portion of watch strap, omitting the buckle, and illustrating the terminal connection, greatly enlarged;

FIG. 2 is a top plan view of the portion of FIG. 1;

FIG. 3 is a side view of a three-layer watch strap, having a reenforcing insert;

FIG. 4 is a perspective view of the attachment of textile material to the tubular element, for example, the reenforcing material of FIG. 3;

FIG. 5 illustrates a different way of attaching textile material to the tubular element; and

FIG. 6 illustrates a different embodiment of interconnection of a multilayer watch strap with the tubular element.

Referring now to the drawings, in particular to FIGS. 1 and 2: the watch strap has a top layer 1 and a bottom layer 2 which are connected together, for example at the edges 3 (2). The two layers 1,2 are connected at one of their ends with a tubular element 4, looped around the element and bonded to the outside surface thereof, for example by adhesion, fusion or the like to the extent that both layers touch the outer surface of element 4. A cross seam 5 may interconnect the two layers 1,2. If the layers are of thermoplastic material, the seam can be done by heat-sealing the layers together.

The tubular element 4 extends essentially over the entire width of the watch band strap. This width corresponds to the length of the cross pin of a watch casing. The tubular element is made of an elastic material, such as thermoplastic material, and is formed with a longitudinal slit 6. As can be seen in the drawings, slit 6 is so arranged that a plane passing through slit 6 and the center of the tubular element, and indicated schematically by the chain-dotted line 7, is roughly parallel to the top layer 1 of the watch strap. The slit 6 could also be rotated somewhat in the downward direction, but preferably should not go beyond a position in which plane 7 would be perpendicular to the top layer 1.

The method of attaching the two layers 1,2 to the outside surface of element 4 depends on the material of the various components. If tubular element 4 is of thermoplastic material such as a polyester, and the layers 1,2 are likewise of thermoplastic material, then all components can be heat-fused together. It is also possible to heat-fuse tubular element 4 to layers 1,2 which are not of thermoplastic material, for example textiles or leather. Of course, the components may also be adhered together by adhesives.

FIG. 3 illustrates a form of construction in which an intermediate reenforcing layer 8 is interposed between top and bottom layer 1,2. The reenforcing material, which contributes to the strength under tension of the watch strap may be made of a textile material, glass fibers, plastic-impregnated textiles, loose fibers, or the like. A loosely woven textile material, having threads made of thermoplastic, or any other material is illustrated in FIG. 4. Reenforcing layer 8 is so secured to tubular element 4 that a transverse, or weft thread 9 falls just behind the edge of the tubular element where reenforcing layer 8 loops therearound. The connection between the tubular element and the reenforcing layer 8 may likewise be by bonding, or fusing, which connection is particularly useful with textile material impregnated with polyvinyl chloride (PVC). PVC-impregnated textile material can, also, advantageously be bonded to the tubular element by bonding at the crossover points between the transverse weft thread and the warp threads 10, for example at points 11 (FIG. 4).

If the watch strap is to be made of only single-layer material, then the material itself may take the position of reenforcing layer 8 (FIG. 4), the layer 8 as illustrated in FIG. 4 then representing the sole portion of the watch strap.

The arrangement of FIG. 5 differs from that of FIG. 4 in the location of attachment of the textile layer 8 (which may be the watch strap itself, or a reenforcement layer) to tubular element 4. As seen in FIG. 5, the interconnection of layer 8 where tubular element 4 is at the edge 12 of slit 6 of tubular element 4, so that the interconnection between the layer 8 and the tubular element is offset by about 90.degree. with respect to the construction shown in FIG. 4.

The end of the watch strap is connected to the cross pin of a watch casing, in accordance with the constructions of FIGS. 4 and 5, by deforming tubular element 4 so that it can be snapped over the cross pin of the watch casing. The inherent elasticity of the tubular element, which, as has been noted, is of elastic material, will cause the element to snap together to an essentially tubular form shown in the drawings, securely retaining the cross pin of the watch casing in position.

The embodiments in accordance with FIGS. 1 and 3 are secured differently; the cross pin of the watch must be pushed from the side into the tubular element and structures in accordance with these embodiments cannot be used with fixedly connected cross pins.

The form of the invention which is most universally applicable is illustrated in FIG. 6; this form additionally has high tensile strength and excellent holding characteristics.

The bottom layer 2 of the watch strap is freely movable with respect to tubular element 4 in the region of slit 6, that is, it is not connected to the edge 13 of the slit. The bottom layer 2 is somewhat elongated and looped into the tubular element, a cross pin 14 of the watch pressing the bottom layer 2 against the inside of the tubular element to form a loop 15 thereagainst. The bottom layer 2 is thus almost entirely looped around the cross pin of the watch casing, reenforcing the end assembly and improving the strength thereof.

The inner diameter of tubular element 4 is preferably chosen to be slightly larger than the diameter of the cross pins with which the strap is to be used, so that the looped portion 15 of the lower part of the strap has sufficient room within the tubular element.

As an illustration, suitable sizes of a typical watch strap are: wall thickness of tubular element 4 0.125 mm.;

thickness of bottom layer 2 0.2 mm.;

thickness of top layer 1 0.4--0.7 mm.

A small projection 16 may be formed in the region of the edge of the slit, to provide additional safety against loss of the cross pin 14, and to increase the pressure which cross pin 14 will exert against the looped portion 15 of the bottom layer, when the entire assembly is placed under some tension. This increases safety against inadvertent opening of the slit, and thus of the interconnection. The projection 16 may be very small, for example 0.3 to 0.4 mm.

Claims

I claim:

1. A watch band having a strap (1,2) formed with an end terminal for connection to the cross pin (14) of a wrist watch casing, comprising:

a tubular element (4) secured to said strap, said tubular element being of elastically deformable material and formed with a longitudinal slit (6), the elasticity of said material being sufficient to permit temporary deformation of said tubular element to enable said element to be snapped over the watch case pin.

2. Watch band according to claim 1 wherein said strap is secured to the outside of said tubular element (FIGS. 1--4).

3. Watch band according to claim 1 wherein said tubular element (4) consists of thermoplastic material, said strap being bonded to said thermoplastic material.

4. Watch band according to claim 1 wherein said strap (5) is secured to the tubular element at an edge (12) of the slit (6).

5. Watch band according to claim 1 wherein said strap is formed with two layers, said tubular elements being positioned relative to said strap such that a plane (7) passing through the slit and the center of the tubular element is approximately parallel to said strap.

6. Watch band according to claim 5 wherein both said layers are secured to said tubular element.

7. Watch band according to claim 1, wherein said strap is formed of a top layer and a bottom layer (6) said top layer being secured to said tubular element and said bottom layer having a portion located in the interior of said element, passing through said slit (6) and surrounding (15) the cross pin (14).

8. Watch band according to claim 7, wherein said bottom layer is movable with respect to said tubular element.

9. Watch band according to claim 1 wherein said strap is formed of two layers and a third reenforcing layer (8) interposed between said two layers, said reenforcing layer being secured to said tubular element.

10. Watch band according to claim 9 wherein said reenforcing layer is of textile material and secured to said tubular element along a transverse, weft thread (9).

11. Watch band according to claim 9 wherein said reenforcing layer is of textile material and secured to said tubular element at crossover points (11) of weft (9) and warp (10) thread.

12. Watch band according to claim 1 including a projection (16) formed on the tubular element in the region of the slit.