GB2117227A

GB2117227A - Watch strap

Info

Publication number: GB2117227A
Application number: GB08208974A
Authority: GB
Inventors: Gonnosuke Satoh
Original assignee: SATOH MANUFACTURING CO Ltd
Current assignee: SATOH MANUFACTURING CO Ltd
Priority date: 1982-03-26
Filing date: 1982-03-26
Publication date: 1983-10-12
Also published as: GB2117227B

Abstract

A watch strap includes a net core and a metal wire closely wound spirally about said net core, wherein said net core is cut to have a uniform width from its intermediate portion to its end connecting a connecting piece and is progressively widened from the intermediate portion to the other end connecting a connecting piece, said progressively widened portion of the net core having longitudinal side edges being outwardly curved with respect to a center line of the net core, said wound metal wire being in close contact with longitudinal side edges of the uniform width portion of the net core, and said wound metal wire biting into said curved side edges of the progressively widened portion of the net core.

Description

SPECIFICATION Watch strap This invention relates to a wristwatch strap, and more particularly to an improved watch strap including a net core and a metal wire closely wound spirally about the net core.

A wristwatch strap including a net core and a metal wire closely wound spirally about the net core has been publicly known (refer to, for example, Japanese Utility Model Publication No.

1,057/38).

This known watch strap has a simple construction whose net core is of a tape-like configuration, so that even if a metal wire is wound spirally about the net core, its appearance is not attractive and is not acceptable because of its low commercial value.

Other than this, a wristwatch strap having a tape-shaped net core whose side edges are curved in a hyperbola by narrowing the side edges and subjected to a finishing process has also been known.

With this known watch strap, the net core is narrowed to form curved edges, the strap has hyperbola side edges which is commercially fresher than the above known watch strap. The net core is, however, thickened by narrowing its width whereby it loses its elasticity and hence increases in hardness resulting in a poor flexibility which makes it difficult to fit the strap against a wrist of a user which is an impermissible shortcoming for a watch strap.

The present invention provides an improved watch strap comprising a net core having side edges outwardly curved by cutting a tape-shaped net blank without narrowing and deforming it and a metal wire closely wound spirally about the net core, thereby without decreasing the elasticity and strength of the net core and without increasing the thickness of the net core, while keeping the flexibility giving the strap a tendency to fit a wrist of a user and a durability for a long use.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a front elevation, partly in longitudinal section, of a watch strap according to the invention; Fig. 2 is an enlarged longitudinal sectional view of a principal part of the watch strap shown in Fig. 1; Fig. 3 is a front elevation of the principal part during one step of the manufacturing the watch strap shown in Fig. 2; and Fig. 4 is a perspective view roughly illustrating one example of the method of manufacturing a watch strap according to the invention.

In the drawings illustrating one embodiment of the watch strap according to the invention a tapeshaped net blank woven by thin metal wires is cut to form a net core (1) hyperbolically tapered. In more detail, the net core (1) has a uniform width from its intermediate portion to a connecting end for a connecting piece (4) and is progressively widened from the intermediate portion to a connecting end for a connecting piece (3). The widened portion of the net core (1) has longitudinal side edges curbed outwardly with respect to a center line or an axis of the net core (1) in the form of a hyperbola as shown in Fig. 3.

With the net core (1) formed above described, the net blank is not deformed for narrowing its width, so that the blank does not lose its elasticity, strength, flexibility and the like at all and does not increase its thickness, with the result that the net core (1) tends to fit a wrist of a user while maintaining its strength.

A metal wire (2) of a square cross-section is closely spirally wound about the net core (1) which has been cut in a predetermined length over its entire length. In the widened portion, inner surfaces of the metal wire are made to bite into the curved edges of the net core (1), while in the uniform wire are in close contact with the side edges of the net core.

One example of a method of manufacturing the watch strap according to the invention will be then exnlained. A produced assembly of a net core (1) with a wire (2) wound thereabout as shown in Fig.

3 is fitted in determined dies shown as an example in Fig. 4 and is pressed in a vertical direction or in vertical and/or horizontal directions to cause the inner surfaces of the metal wire (2) to bite into the curved side edges of the progressively widened portion of the wire core (1) so that the outside of the wound metal wire (2) is snuggly formed in smoothly curved shape along the side edges of the net core (1) shown in Fig. 1 and 2. On the other hand, in the uniform portion of the net core (1) the inner surfaces of the metal wire (2) are brought into close contact with side edges of the net core (1 ) and the outside of the wound metal wire (2) is smoothly finished.Thereafter, to the end of the widened portion of the net core (1) is fixed the connecting piece (3) for connecting to a wrist watch (not shown), while to the end of the uniform portion of the net core (1) is fixed the connecting piece (4) for connecting to a connecting fixture (5).

Two watch strap portions thus assembled are then connected to each other by connecting two connecting pieces (4) by means of the connecting fixture (5) to obtain a complete watch strap.

It is to be understood that the method of manufacturing the watch strap is not limited to the method above described which is only one example.

As above described, the watch strap including a net core and a metal wire closely wound spirally about the net core according to the embodiment comprises the net core having a uniform width from its intermediate portion to its end connecting a connecting piece by cutting from a net blank and progressively widened from the intermediate portion to the other end connecting a connecting piece by cutting from the net blank so as to form outwardly curved longitudinal side edges of the progressively widened portion with respect to a center line of the net core in the form of a hyperbola without narrowing and deforming the net core, thereby without losing the elasticity, strength and flexibility of the net blank and without increasing its thickness and hardness.

Accordingiy, the watch strap according to the embodiment is fresh in configuration, superior in flexibility and apt to fit a wrist of a user. Moreover, as the wound metal wire is brought into close contact with the longitudinal side edges of the net core in the uniform portion and bites into the curved side edges of the net core in the progressively widened portion, the watch strap is not only capable of reinforcing the longitudinal side edges of the net core by the metal wire to prevent the net core from loosening but also obtaining smoothly curved side edges of the exposed outside of the metal wire along the side edge of the net core by the construction of the bitten metal wire into the side edges of the net core to provide an aesthetical appearance and a firm fixation of the metal wire to the net core which further provides a durability of the strap eliminating a separation of the net core and metal wire for long use. Therefore, the invention provides a high quality watch strap which is superior in elasticity, strength and flexibility in conjunction with the high quality of the net core to the prior art watch strap and apt to fit a wrist of a user.

Accordingly, the above mentioned object is accomplished by the above features of the embodiment of the invention.

Claims

1. A watch strap including a net core and a metal wire closely wound spirally about said net core, wherein said net core is cut to have a uniform width from its intermediate portion to its end connecting a connecting piece and is progressively widened from the intermediate portion to the other end connecting a connecting piece, said progressively widened portion of the net core having longitudinal side edges being outwardly curved with respect to a center line of the net core, said wound metal wire being in close contact with longitudinal side edges of the uniform width portion of the net core, and said wound metal wire biting into said curved side edges of the progressively widened portion of the net core.

2. A watch strap according to claim 1, wherein the edges of the net core are hyperbolically curved to effect the widening of the net core.

3. A watch strap substantially as hereinbefore described with reference to the accompanying drawings.

4. A method of producing a watch strap having a net core and a metal wire spirally wound about said net core, wherein said net core is cut to have a uniform width from its intermediate portion to its end connecting a connecting piece and is progressively widened from the intermediate portion to the other end connecting a connecting piece, said progressively widened portion of the net core having longitudinal side edges being outwardly curved with respect to a center line of the net core, said wound metal wire being in close contact with longitudinal side edges of the uniform width portion of the net core, and the net core and wire are forced in dies to cause the metal wire to bite into said curved side edges of the progressively widened portion of the net core.