GB2107966A - Watch strap - Google Patents

Abstract

An improved watch strap is provided which includes a net core 1 and a band plate closely wound spirally about said net core, comprising a cover plate consisting of upper and lower pieces a1 and a2 one upon the other in a pair to cover a distal end 1a, shaped in the form of a trapezoid, of said net core extending from an end of said band plate on a side connecting a watch body, said lower piece being formed at a center of its band-like flat plate with an engaging groove a'2 engageable with said trapezoid end 1a' of said net core 1, and said upper piece a1 being formed in a band-like plate whose side edges are bent over side edges and a lower surface of said lower piece so as to urgingly fix said upper piece to said net core and said lower piece. <IMAGE>

Description

SPECIFICATION Watch strap This invention relates to a wristwatch strap, and more particularly to an improved construction of a processed distal end of a watch strap including a net core.and a band plate closely wound spirally about the net core.

In hitherto used watch straps of this kind, a brazing method has been used for fixation of a watch body fixing end of a band plate closely wound spirally about a net core. In order to avoid oxidation at the fixed surfaces in brazing to achieve a complete fixation, a flux such as chloride, fluoride or the like has been used.

However, when a cleaning liquid (nitric acid) is used to remove the remaining flux after the fixation, there is often a risk of dissolving and removing brazing filler from the fixed portion.

Moreover, if the remaining flux is not completely removed, the flux would preclude complete plating in a subsequent process or plated layer on the remaining flux is apt to peel resulting in corrosion.

In addition, the cleaning liquid or the like would give rise to a pollution.

It is an object of the invention to provide a watch strap end construction in which the aforesaid disadvantages are obviated or mitigated.

According to the invention there is provided a watch strap comprising a cover plate consisting of upper and lower pieces one upon the other in a pair to cover a distal end, shaped in the form of a trapezoid, of said net core extending from an end of said band plate on a side connecting a watch body, said lower piece being formed at a center of its band-like flat plate with an engaging groove engageable with said trapezoid end of said net core, and said upper piece being formed in a bandlike plate whose side edges are bent over side edges and a lower surface of said lower piece so as to urgingly fix said upper piece to said net core and said lower piece.

One embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a bottom plan view of a part of a strap, according to the invention; Fig. 2 is a side view of the watch strap part shown in Fig. 1; Fig. 3 is a sectional view of the watch strap part taken along the line X X in Fig. 2; Fig. 4 is a sectional view of the watch strap part taken along a line Y-Y in Fig. 2; and Fig. 5 is an exploded perspective view of a part of the end of the watch strap shown in the other figures.

Referring to the drawings illustrating one embodiment of the watch strap according to the invention, a cover plate (a) consists of a pair of pieces, one upon the other that is, upper and lower pieces (at) and (a2). A band plate (2) is closely wound spirally about a net core (1) to form a watch strap (A). The cover plate (a) is so sized as to cover a draw protecting portion (1 a') of the net core which extends from an end of the band plate (2) diverging in the form of a trapezoid towards a watch body (B) and which is formed integrally with a distal end (lea) of the net core (1) extending from one end of the band plate (2) of the watch strap (A) on the side of the watch body (B).

The lower piece (a2) is formed at the center on the upper side of its band-like plate with an engaging groove (a'2) having an oblique surfaces (a"2) (a"2) for preventing the lower piece (a2) from removing from the above mentioned trapezoid portion of the net core (1) and is formed on the lower side with draw protecting surfaces (a"2) (a"2) oblique in the same directions as those of the oblique surfaces (a"2) (a"2) of the engaging groove (a'2) for preventing the upper piece (a1) from removing from the lower piece (a2). The upper piece (a1) is a band-like flat plate.

The net core (1) is in the form of a tape-shaped strap made of a net blank woven by thin metal wires. The band plate (2) is a very long metal wire having a square cross-section and closely wound spirally about the entire length of the net core (1 ) except its distal end (1 a).

A method of mounting the cover plate (a) onto the watch strap will be explained hereinafter. First the trapezoid distal end of the net core (1) is fitted in the engaging groove (a'2) of the lower piece (a2, and then the upper piece (a1) is brought onto the upper surfaces of the lower piece (a2) and the distal end of the net core (1).

Thereafter, side edges of the upper piece (a1) are bent over the side edges of the lower piece (a2) and further bent over the lower surface of the lower piece (a2) by pressing to bind the net core and upper and lower pieces integrally so as to cover all the outer surfaces of the distal end (lea) of the net core (1) by the upper and lower pieces.

The ends of the upper piece (a1) are chamfered so as to engage the draw protecting surfaces (a"'2) to prevent the piece (a2) from being pulled out of piece (a1) as a result of tension in the net core.

To cover plate (a) of the watch strap (A) thus assembled is then fixed a connecting piece (3) for connecting the watch body (B) and to the other end is fixed a connecting piece (not shown) for connecting a connecting fixture and thereafter the assembly is subjected to further processes such as plating to obtain a complete watch strap.

The watch strap including a net core and a band plate closely wound spirally about the net core according to the embodiment comprises a cover plate consisting of upper and lower pieces covering a distal end in the form of a trapezoid extending from the net core on the side connecting a watch body so as to be able to securely fix the distal end of the net core without brazing, so that there is no risk of corrosion due to brazing and the watch strap keeps its oesthetical appearance.

Furthermore, according to the embodiment, the trapezoid distal end of the net core is engaged with the engaging groove of the lower piece, thereby completely preventing the cover plate from removing from the net core and reliably preventing the turns of the band plate from being shifted to provide a high quality watch strap.

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

Claims (3)

1. A watch strap including a net core and a band plate closely wound spirally about said net core, comprising a cover plate consisting of upper and lower pieces one upon the other in a pair to cover a distal end, shaped in the form of a trapezoid, of said net core extending from an end of said band plate on a side connecting a watch body, said lower piece being formed at a center of its band-like flat plate with an engaging groove engageabie with said trapezoid end of said net core, and said upper piece being formed in a bandlike plate whose side edges are bent over side edges and a lower surface of said lower piece so as to urgingly fix said upper piece to said net core and said lower piece.

2. A watch strap according to claim 1, wherein said upper piece has chamfered ends which engage tapered shouiders on the underside of the lower piece preventing the lower piece from being pulled out of the upper piece as a result of tension in the net core.

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