US2729056A - Snap-attached case and back of a clock - Google Patents

Description

Jan. 3, 1956 c. H. ARNOLD SNAP-ATTACHED CASE AND BACK OF A CLOCK Filed Sept. 25, 1952 Hiram/2:545.

United States Patent SNAP-ATTACHED CASE AND BACK OF A CLOCK Charles Henry Arnold, Colebrook River, Conn., assignor to The William L. Gilbert Clock Corporation, Winsted, Conn., a corporation of Connecticut Application September 25, 1952, Serial No. 311,443

2 Claims. (CI. 58-53) This invention relates to timepieces in general, and to clocks in particular.

The type of clock to which the present invention relates carries the movement on a rear plate which is secured to and covers the open back of the clock case for most facile assembly of the movement with the rest of the clock' Usually, the movement-carrying rear plate is secured to the open back of the clock case by screws which form a rigid connection between the rear plate and clock case, with the result that shock or vibration to which the clock case may be subjected is rather freely transmitted to the movement. It is for this reason that clocks of this type become sometimes impaired and even damaged during ordinary shipment from the factory, and they become almost certainly damaged when dropped accidentally. Further, the task of driving screws into the clock case for the attachment of the movement-carrying rear plate to the open back of the case has been found laborious and tiresome, especially in the case of plastic-molded clock cases which are usually provided with cored-out holes in which the screws cut their own threads when being applied.

It is an object of the present invention to provide a clock of this type which is far more shock and vibration resistant than previous clocks of this type, so that the present clock wil hardly become impaired or damaged in ordinary transit, and will more often than not survive accidental dropping Without appreciable damage.

It is another object of the present invention to provide a clock of this type of which the movement-carrying rear plate is mounted in the open back of the clock case by being simply snapped in place therein, thereby not only eliminating the laborious and tiresome task of applying the plate-attachment screws to the cases of previous clocks of this type, but also saving the cost of these screws.

A further object of the present invention is to provide a clock of this type of which the entire clock case is somewhat resilient and is deformed when the movementcarrying rear plate is snapped in place therein, so that the case will, on its recovery, be interlocked with the snappedin plate and hold it in place as securely as if the same were an integral part of the case.

Another object of the present invention is to provide a clock of this type of which the resilient case is on its inside provided not only with a plurality of relatively deep notches for interlock with the movement-carrying plate, but also with wedge formations which lead to these notches and which will give readily when the rear plate is forced thereover into interlock with the notches, thereby requiring only simple inward pressure against the rear plate at the open case back in order to snap the former securely in place therein and accurately position the movement in the case without any further attention from the assembler.

It is a further object of the present invention to pro vide a clock of this type of which the open back of the clock case is somewhat larger than the movement-carry- ICC ing rear plate, so that the case will, on the snap-in application of the rear plate, be resiliently deformed without being subjected to appreciable tensile stresses, with the result that the snap-in pressure or force to be exerted on the rear plate may be comparatively moderate.

Another object of the present invention is to provide a clock of this type of which the aforementioned notches and wedge formations are located in the open back of the clock case on only two opposite sides thereof, so that the case back will, on the snap-in application of the rear plate, be momentarily spread in one general direction and permitted to contract simultaneously in a transverse direction, with the result that an even more moderate force on the rear plate will snap the same in place.

it is another object of the present invention to provide a clock of this type of which the aforementioned notches in the open case back are sufliciently deep to permit substantially complete recovery of the case to its original shape after the movement-carrying rear plate has been snapped in place therein, so that the case is not subjected to any appreciable permanent stresses that could the more readily bring about damage to the case if the clock were dropped accidentally.

Another object of the present invention is to provide a clock of this type of which the aforementioned notches in the open case back are relatively short, few in number, and their bottoms are preferably somewhat spaced inwardly from the case wall, so that the snapped-in movement-carrying rear plate is throughout the far greater part of its circumference spaced from the case wall slightly but nevertheless sufliciently to preserve the resiliency of the case to such an extent that the latter will more often than not withstand even considerable shock or vibration without becoming appreciably damaged, it at all, and will absorb most of these disturbing forces before they may cause any appreciable damage to the movement.

it is a further object of the present invention to provide a clock of this type of which the case is conveniently and economically formed of slightly resilient plastic and has relatively thin walls to lend the case considerable resiliency, with the result that a comparatively small force is required to snap the movement-carrying rear plate into the case back and only a moderate force need be exerted on the case back to spread the same sufiiciently for intended removal from the case of the rear plate and the movement thereon for repair or other purposes, yet the case, with the rear plate snapped in place therein, is fully as rigid as clock cases are required to be.

Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. l is a reduced front view of a clock embodying the present invention;

Fig. 2 a side view of the clock;

Fig. 3 is an enlarged rear view of the clock;

Fig. 4 is a section taken substantially on the line 4-4 of Fig. 3; and

Fig. 5 is a fragmentary rear view of the clock similar to Fig. 3, showing the clock shortly before its final assembly.

Referring to the drawings, and more particularly to Figs. l to 4 thereof, the reference numeral 10 designates a timepiece, in this instance a clock, which comprises a case 12, a movement 14 carrying a time dial 16, a rear plate 18 and a dial-covering crystal 20. The case 12 is slightly resilient and has a front 22 with a bezel 24, an open back 26, and an uninterrupted peripheral wall 28 between front and back. The case 12 may assume any desired shape, and is in this instance generally rectangular, leaving the peripheral case wall 28 with top and bottom portions 30 and 32 and opposite side portions 34 and 36. p

The movement 14 may be mechanical or electrical, and is in this instance indicated in an abbreviated fashion as mechanical (Fig. 4), the prime mover being a mainspring 38. The movement 14 has the usual pillar-spaced end plates 4i) and 42, as well as minute and hour hands 44 and 46 on the customary arbors. The time dial 16 is suitably mounted on the end plate 40 behind the minute and hour hands 44 and 46.

The movement 14 is carried at 47 on the rear plate 18. The movement 14 may thus be conveniently preassembled with the rear plate 18, so that the former will be quickly placed and correctly located in the case 12 on simply mounting the rear plate in the case. In recur"- ance with the present invention, the rear plate 18 is mounted in the open back 26 of the case by being simply sprung or snapped therein. To this end, the case 12, and more particularly the peripheral wall 23 thereof, is provided with a plurality of spaced inner ribs or projec tions 5t) which are provided with notches 52, respectively, adapted for interlock with the periphery of the rear plate 18. Each of the ribs 50 is in part formed as a wedge 54 (Fig. 4) which extends axially of the case 12 and ascends substantially from the case wall 23 at or near the open case back 26 toward the adjacent notch 52.

The movement 14 is, in the present instance, of a size to be received in the case 12 with clearance from the peripheral wall 43 thereof (Fig. 4). The rear plate 18, with which the movement 14 is pie-assembled as described, is mounted in the case 12 by simply forcing it planewise into the open case back 26. In doing so, the periphery of the rear plate 18 will spring or snap over the wedges 54 into interlock with the notches 52. The crystal 2t), having been placed in the bezel 24 through the open case back 26 prior to the snap-in of the rear plate 13, will on the subsequent snap-in of the latter be engaged by the time dial 16 and securely held thereby in the bezel 24.

The rear plate 18 is preferably somewhat smaller than the opening in the case back 26, and the notches 52 are preferably of such depths that the rear plate permits sub stantially complete recovery of the case 12 to its original shape (Fig. 3) after the former has been snapped or sprung in place therein. Accordingly, while the case 12 is only momentarily deformed, and hence tensioned, during the actual snap-in of the rear plate 18, it is not subjected to any appreciable permanent stresses after the rear plate has been snapped in place therein.

While the case 12 may be made of any suitable slightly resilient material, such as sheet'metal, for instance, the same is in this instance molded of slightly resilient plastic. In order to lend considerable resiliency to the case 12 as well as economize in the amount of plastic required for the case, the peripheral wall 28 and preferably also the front wall 22 thereof are made relatively thin. The molded case 12 may, at least in the corners of the peripheral wall 28 thereof, be reenforced by integral rib formations 60 which terminate in posts 62 that extend to the snapped-in rear plate 18 and serve as abutments therefor. Further, the notched ribs or projections 56, by extending throughout the width of the peripheral case wall 28 for most facile and economical molding of the case, further reenforce the latter without appreciably detracting from its overall resiliency.

While the rear plate 18 is somewhat smaller in size than the opening in the back of the case 12 (Fig. 3), it is preferably of a shape similar to that of this opening so that the snapped-in rear plate will substantially cover the open case back 26 and protect the movement 14 from dust and other foreign matter.

As shown in Fig. 4, the bottoms of the notches 52 in the ribs 50 are preferably slightly spaced inwardly from the peripheral case wall 28 so that the non-interlocked peripheral portions of the rear plate 18 may have slight clearance from the peripheral case wall 28 (Fig. 3). Further, the ribs 50 are preferably few in number and their notches 52 are relatively short, so that by far the greater part of the periphery of the mounted rear plate 18 may substantially clear the peripheral case wall 23. As shown also in Fig. 3, the ribs 59 are located on only two opposite sides of the peripheral case wall 28, in this instance on the top and bottom portions as and 32 thereof. in having by far the greater part of the periphcry of the mounted rear plate 18 substantially clear of the peripheral case wall 28, the case 12 will retain a good deal of its resiliency, with the result that the case will not only act as a very effective shock absorber for the movement 14, but may itself withstand considerable shock or vi bration without becoming damaged. If the instant clock should be subjected to more severe shock, as by accidentally dropping the same, the case 12, if sustaining any damage at all, will more often than not be damaged much less than a similar case to which the movement-carrying rear plate is attached by screws as heretofore. Thus, two clocks of the instant type, one with the rear plate snappedin the case and the other with the rear plate screwed in the case, were repeatedly dropped onto the floor from a height over a yard, with the result that the clock with the snapped-in rear plate sustained minor damage to the case but kept running accurately and could well be used thereafter despite the damage to the case, while the other clock was damaged beyond repair, especially insofar as the case was concerned.

By providing the ribs 50 on only two opposite sides of the peripheral case wall 28 as described, and since the rear plate 18 is made somewhat smaller than the opening in the case back 26, the case 12 will momentarily be spread in the general direction of the arrow 6-. in Figs. 3 and 5, and permitted to contract simultaneously in a direction transverse thereto, when the rear plate is snapped in place in the case (see particularly Fig. 5). Thus, the case 12, and particularly the peripheral wall 28 thereof, will primarily be resiliently deformed and not subjected to any considerable tensile stresses when the rear plate 18 is snapped in place in the open case back 26, with the result that only a moderate force is required to snap the rear plate in place, or to remove the same from the case for repair or other purposes.

Instead of merely forcing the rear plate 13 planewise into the open case back 26 for its snap-in attachment thereto as described, either the top edge or the bottom edge of the rear plate may first be placed into interlock with the adjacent pair of notches 52 before the rest of the rear plate is forced inwardly into the case back for snapping the opposite edge of the rear plate into interlock with the other pair of notches 52. In following this alternative course, the case 12 is less deformed momentarily and correspondingly less force is required to snap the rear plate in place. Further, if it should be contemplated to mount the rear plate in accordance with this alternative mode, only one of the opposite pairs of ribs 50 need be formed with wedges 54, as will be readily understood.

The rear plate 18, being preferably made of relatively rigid sheet metal for the secure mounting thereon of the movement 14, has nevertheless slight spring characteristics by being ofiset at 70 (Figs. 3 and 4). The slightly springy rear plate 18 not only protects the movement 14 even further from shock or vibration to which the case 12 may be subjected, but also accomplishes somewhat yielding retention of the crystal 20 in the bezel 24 by the time dial 16.

The invention may be carried out in other specific ways than those herein set for without departing from the spirit and essential characteristics of the invention,.and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.

What is claimed is:

1. A clock comprising a case of slightly resilient material having an open back, a front with a dial aperture, and an endless peripheral wall between front and back, said wall having angularly spaced notched inward projections formed in part as wedges, respectively, extending axially of the case and ascending substantially from said Wall near said open back toward said front to the respective notches, and the latter having bottoms spaced inwardly from the adjacent inner surface of said wall; a movement receivable in said case with clearance therefrom; and a movement-carrying rear plate shaped similarly as, but slightly smaller than, the opening in said case back, so that the periphery of said plate may be sprung over said wedges into the respective notches for the secure attachment of said plate to the case with the movement in the latter and the periphery of said plate slightly spaced from said inner wall surface, said rear plate having an inner web portion on which said movement is mounted and which is spaced inwardly from said projections on said case wall, and an uninterrupted peripheral marginal portion laterally offset from the plane of said Web portion, thereby lending spring characteristics to said plate.

2. A clock comprising a case of slightly resilient material having an open back, a front with a dial aperture, and an endless peripheral wall between front and back,

said wall having angularly spaced notched inward projections formed in part as Wedges, respectively, extending axially of the case and ascending substantially from said wall near said open back toward said front to the respective notches, and the latter having bottoms spaced inwardly from the adjacent inner surface of said Wall; a movement receivable in said case with clearance therefrom; and a movement-carrying rear plate shaped similarly as, but slightly smaller than, the opening in said case back, so that the periphery of said plate may be sprung over said wedges into the respective notches for the secure attachment of said plate to the case with the movement in the latter and the periphery of said plate slightly spaced from said inner wall surface, said rear plate having an inner web portion on which said movement is mounted and an uninterrupted peripheral marginal portion laterally offset from the plane of said web portion, thereby lending spring characteristics to said plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,619,674 Kohn Mar. 1, 1927 1,752,651 Porter Apr. 1, 1930 2,012,002 Finch Aug. 20, 1935 2,078,476 Whitehead Apr. 27, 1937 2,254,599 Carlson Sept. 2, 1941 2,515,669 Scholl July 18, 1950 FOREIGN PATENTS 404,502 Atkins Jan. 18, 1934

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