GB2176319A - An electric watch - Google Patents

Abstract

An electric watch comprises connecting means for connecting two base plates - a metal frame 10 and a plastic frame 26 - and all of the remaining elements of the watch movement. The connecting means are formed by a spring clip 54 with a plate-like body and at least two spring legs 54a, 54b, 54c, bent at an angle, which releaseably interlock with associated mating elements of the metal frame when the body of the spring clip rests on the plastic frame and/or further components arranged thereon. In addition, spring projections 54d to h which may be made to abut under pretension further elements of the watch are provided on the body of the spring clip. <IMAGE>

Description

SPECIFICATION An electric watch The invention relates to an electric watch and more particularly to an electric watch comprising a metal frame, a plastic frame, a watch drive having at least one rotatable element, wherein wheels of the watch movement and possibly the rotatable element of the watch drive are arranged between the facing inner sides of the metal frame and the plastic frame and are mounted in bearing holes of these frames, and also comprising connecting means for connecting the metal frame and the plastic frame and all of the remaining elements of the watch movement.

In the assembly of such watches, the standard procedure is to first insert one shaft end of various wheels of the watch movement and also one shaft end of the rotor-or more strictly speaking the rotor arrangement-of the stepping motor into the bearing holes of the metal frame provided for this pupose, and to then position the plastic frame on the thus obtained arrangement in such a way that the respective other shaft ends of the wheels of the watch movement and of the rotor enter the bearing holes of the plastic frame provided for this purpose. The plastic frame is then usually screwed to the metal frame, with the spacing between plastic frame and metal frame generally being determined by spacers which are already fixedly connected to the metal frame during assembly and which are provided at their free end with a threaded bore.In this way, the respective wheels of the watch movement, the rotor and, also the stator of the stepping motor are secured in the desired mutual position between the two frame elements as shown in German Auslegeschrift 1 257 690 for example. In certain cases, corresponding spacers may also be formed on the plastic frame.

Connecting means in the form of screw connections have, as far as manufacturing techniques are concerned, not proven fully satisfactory on account of the necessary internal threads and the substantial assembly time for tightening the screws, which causes an overall increase in the costs of the watch. A further disadvantage is that the elements of the watch movement which are not arranged between the two frame elements and which, according to an earlier proposal, for example, also include the complete stator arrangement, require additional attachment means, which involves additional manufacturing and assembly costs. These basic problems also arise if, in accordance with a further recent proposal, at least the elements of a subgroup are joined by a spring clip to form one structural unit prior to the final assembly.

It is accordingly an object of the invention to improve the connecting means in an electric watch having a metal frame and a plastic frame so that a reliable releaseable connection may be made at least between the metal frame and the plastic frame in an inexpensive and rapid manner.

According to the present invention there is provided an electric watch comprising a watch movement including a metal frame, a plastic frame, a watch drive having at least one rotatable element, the watch movement having a plurality of wheels which are arranged between the facing inner sides of said metal frame and said plastic frame and which are mounted in bearing holes formed in said frames, and connecting means in the form of a spring clip which connects said metal frame and said plastic frame, said spring clip comprising a plate-like body which overlies said plastic frame and at least two spring legs depending therefrom, said spring legs being releasably interlocked with associated mating portions of the metal frame, and said body also having one or more spring projections which resiliently abut other parts of the watch.

The spring clip is preferably punched from spring sheet metal and bent as a relatively simple component which, after assembly of the plastic frame in relation to the metal frame, and possibly after further components have been arranged on the upper side of the plastic frame, is simply pressed from above onto the pertinent components or the plastic frame, with the spring legs, which are bent at an angle, being expanded in an outward direction so as to then snap into associated mating elements of the metal frame.

In a preferred embodiment of the invention, the mating elements of the metal frame are recesses along the outer circumference of the metal frame into which the spring legs of the spring clip drop when the latter is pressed on.

Transverse webs at the lower or free end of the spring legs abut from below edge areas of the aforementioned recesses, and the pertinent edge may be set back somewhat in relation to the outside surface of the metal frame to enable flat abutment of the metal frame at the rear side of the dial.

Preferably said one or more of said additional spring projections of the spring clip securely fix a further component with respect to the frame elements. One spring projection can be used as a contact spring for a battery and/or as a contact spring for a contact element of an electronic circuit, in which case, the latter may, for example, comprise a printed circuit whose printed circuit board is placed in the desired position on the upper side of the plastic frame by projections of the plastic frame, on the one hand, and by openings in the printed circuit board, on the other hand.

In another preferred embodiment another spring projection of the spring clip constitutes a detent spring for a stem. Several of the aforementioned additional functions and possi bly also further functions may, of course, be simultaneously realized by several spring projections, more particuarly, integrally formed on the body of the spring clip.

One embodiment of the invention will now be described in more detail. The description makes reference to the accompanying diagrammatic drawings in which: Figure 1 is a plan view of the rear. side of the completely assembled watch movement of an electric watch according to the invention; Figure 2 with the detailed Figures 2a to 2h are a plan view and various cross-sections of the spring clip of the watch movement according to Figure 1; Figure 3 is a cross-section through the completely assembled watch movement according to Figure 1 taken along the line 3-3 in that Figure; and Figure 4 is a plan view of the inner side of the metal frame of the watch movement according to Figure 1.

Figures 1 and 3 show in detail a watch movement comprising as a base element a metal frame 10, on the front or bottom side of which a dial 12 is disposed, for example, adhered thereto or clamped thereto by means of small feet.

The watch is assembled as follows: The metal frame 10 which is formed with bores and recesses and the inner side of which is shown in detail in Figure 4, is first inserted into an assembly holder (frame receiving means), which is not illustrated in the drawings. The front or lower shaft ends of a rotor 20 of a stepping motor, of a central wheel 22 and of a change-over and setting wheel 24 are then inserted into the bearing holes 14, 16, 18 of the metal frame 10 provided for this purpose. A plastic frame 26 is subsequently placed onto the thus obtained arrangement in such a way that the rear or upper shaft ends of the rotor 20 and of the wheels 22, 24 of the watch movement are received by associated openings 28, 30, 32 of the plastic frame 26.

A sheet metal stator 34 with an exciter coil 36 is then arranged on the outer side of the plastic frame 26, and the sheet metal stator 34 is positioned with respect to the plastic frame 26 with the aid of projections of the plastic frame 26 which penetrate corresponding associated openings in the sheet metal stator. One of these projections is illustrated in Figure 3 as projection 26a of the plastic frame. During the same assembly step, a first intermediate wheel 38 is, furthermore, placed onto a pivot 26b provided for this purpose on the outer side of the plastic frame 26. In the same assembly plane, a spring finger (not illustrated) for spring support of the watch movement battery (not illustrated) is, furthermore, placed onto a pin provided for this purpose on the plastic frame.

In the next assembly plane, a second intermediate wheel 40 which meshes with a pinion of the rotor and which comprises a pinion which meshes with the first intermediate wheel, is placed onto a pivot 42 which has already been inserted, prior to assembly of the plastic frame 26, from the inner side of the latter, into an opening of the plastic frame 26 provided for this purpose. In this assembly plane, there is, furthermore, placed onto a further pin of the plastic frame 26, a bridge element (not illustrated) which magnetically bridges an open gap in the sheet metal stator which is necessary for pushing on the exciter coil 26. A spacer (not illustrated) is, furthermore, placed onto one of the projections of the plastic frame 26 serving to position the sheet metal stator 34.

In the next assembly plane, an electronics module of the watch movement with a printed circuit board 44 is now placed onto positioning projections provided for this purpose on the plastic frame. A cast integrated circuit 46 is already arranged onto the printed circuit board 44, and a quartz crystal 48 and a capacitor 50 are, furthermore, mqunted laterally on the printed circuit board.There is, furthermore, inserted into a lateral opening 26c of the plastic frame a stem 52 which comprises at its inner end a pinion 52a for cooperating with a toothing 24a of the change-over and setting wheel 24 when the stem 52, which is illustrated in Figure 3 in its iriside position, is located in its outside position, with the inside and the outside position of the stem 52 being defined by annular grooves 52c and 52d which co-operate with a detent spring element which shall be referred to in further detail, and between which there is located an annular rib 52e which is bevelled on both sides.

After completion of the above-described assembly steps, the spring clip 54 shown in detail in Figure 2 is pressed, in a final assembly step, from above onto the thus obtained entire arrangement. The stem can also only be inserted when the watch movement is installed into the watch casing. Here, the three spring legs 54a, 54b and 54c bent at an angle are first expanded somewhat in an outward direction and then fall into the recesses 10a, lOb and 1 Oc provided for this purpose on the circumference of the metal frame 10.

Outwardly protruding projections 54a', 54b' and 54c' enter cut-out sections 10a', 10b" and 10c', whereby the spring clip 54 is releasably interlocked with the metal frame 10.

This lock may be released for maintenance and repair work by pressing the spring legs in an outward direction. For this purpose, there is provided in each spring leg 54a to 54c, in the area in which it is bent at an angle one opening 60 which permits application of a suitable tool. Cross-sections through the spring legs 54a to 54c along the intersection lines c-c; f-f and h-h are illustrated in the detailed Figures 2c, 2f and 2h to elucidate the structural design of the spring clip 54.

As is apparent from Figure 2, the spring clip 54 comprises in addition tothe spring legs 54a to 54c, a number of further spring projections 54d with the cross-section shown in Figure 2a along line a-a in Figure 2; 54e with the cross-section shown in Figure 2b along line b-b in Figure 2; 54f with the cross-section shown in Figure 2d along line d-d in Figure 2; 54g with the cross-section shown in Figure 2e along line e-e in Figure 2 and 54h with the cross-section shown in Figure 29 along line gg in Figure 2.

The spring projection 54d which is bent at an angle at its free end serves as positive contact for the battery of the watch. The spring projection 54f furthermore serves to hold down the printed circuit board 44. Also, the spring projection 549 serves as contact spring for a contact element of the printed circuit on the printed circuit board 44. Finally, the spring projection 54h with its free end bent at an angle serves as detent spring for the stem 52.

In addition to the spring legs and the spring projections, the plate-like body of the spring clip 54 is provided with impressions 62 which form on the inner side of the spring clip 54 wart-like protrusions which may, for example, serve as additional means for holding down the printed circuit board 44 and as axial stops for shaft ends of wheels of the watch movement.

It is apparent from the above description that the spring clip 54 which constitutes a releasable connecting means between the plastic frame and the metal frame is a multipurpose component which, in addition to its function as connecting means, may fulfil numerous additional functions which in a conventionally designed watch movement of an electric watch require a corresponding number of additional components. Accordingly, the number of components for the watch movement can be noticeably reduced. On the other hand, in spite of its, at first sight, very complicated design, the spring clip 54 can be manufactured in mass production with the aid of a corresponding tool set, comparatively simply and inexpensively by punching, stamping and bending spring sheet metal.

Finally, with reference to the terminology used in the application, it is pointed out that the designations "metal frame" and "plastic frame" were selected so as to comply with the English terminology whereas the classical designations for the aforementioned components are, in general, "metal base plate" or "metal plate" and "plastic base plate". In the instant case, the designation "plastic frame" could also be replaced by the designation "intermediate plastic plate" on account of the plate-like body of the spring clip, in which case the body of the spring clip should then be regarded as a cover plate.

Claims (8)

1. An electric watch comprising a watch movement including a metal frame, a plastic frame, a watch drive having at least one rotatable element, the watch movement having a plurality of wheels which are arranged between the facing inner sides of said metal frame and said plastic frame and which are mounted in bearing holes formed in said frames, and connecting means in the form of a spring clip which connects said metal frame and said plastic frame, said spring clip comprising a plate-like body which overlies said plastic frame and at least two spring legs depending therefrom, said spring legs being releasably interlocked with associated mating portions of the metal frame, and said body also having one or more spring projections which resiliently abut other parts of the watch.

2. A watch according to claim 1, wherein one spring projection is in the form of a contact spring for a battery.

3. A watch according to claims 1 or 2, wherein one spring projection is in the form os a detent spring for a stem.

4. A watch according to one of claims 1 to 3, wherein one spring projection is in the form of a contact spring for a contact element of an electronic circuit.

5. A watch according to one of claims 1 to 4, wherein the mating elements are in the form of recesses along the outer edge of the metal frame and wherein the spring legs of the spring clip are provided with lateral projections which abut edge areas of the recesses at the outer side of the metal frame.

6. A watch according to claim 5, wherein the edge areas are in the form of cut-out sections which are recessed in the outer side of the metal frame.

7. A watch according to one of claims 1 to 6, wherein the base of the spring clip is provided on its outer side with impressions and on its inner side with corresponding protrusions which serve as holding down elements.

8. An electric watch substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.