US1646841A - Resilient crystal for clocks and like instruments - Google Patents

Description

t. l 2 l 646 841 0c 9 7 R. H. WHITEHEAD ET AL HESILIENT CRYSTAL FQR CLOCKS AND LIKE' INSTRUMENTS Filed Nov. 9, 1926 vided with yielding crystals of celluloid or Patented oer. 25, 1927'.

' UNITED STATES PATENT OFFICE.

BICI IABD' H. WHITEHEAD AND WILSON E. PORTER, OF ,NEW HAVEN, CONNECTICUT,

: ASBIGNOBS TOTHE NEW HAVEN CLOCK 00., OF NEW HAVEN, CONNECTICUT, A COR- PORLTION.

v BESILIENT CRYSTAL FOR CLOCKS AND LIKE INSTRUMENTS.

Application fl'led November 9, 1926. Serial No. 147,255.

Our invention relates to an improvement in-that class of small portable clocks proequivalent, non-breakable, transparent material, in place of rigid crystals of glass, the object being to produce, at a low cost for manufacture, a high-grade and attractive clock having the advantages incident to the use of a non-breakable crystal, together with some manufacturing'advantages to hereinafter appear.

With these ends in view, our invention consists in a resilient crystal having its actual edges initially bowed out of a common plane so that when such edges are placed under tension from their opposite faces, they will be brought substantially into a common plane, whereby the case-unit and the movement-unit of the clock in which the said crystal is placed will be stabilized in their relative positions by the effort of the said bowed edges of the crystal to resume their initially-bowed form.

In the accompanying drawings:

Fig. 1 is a View in vertical central 'section ofone form which a celluloid-crystal clock embodying our invention may assume;

Fig. 2 is a corresponding view thereof before the crystal has been placed under ten- S1011 Fi 3 is a detached plan view of the crystal a ter it has been bowed;

Fig. 4 is an edge view thereof; and

Fig. 5 is an end view thereof.

In carrying out our invention, as herein shown, we employ an oblong, rectangular,

. convex, yielding crystal 10 of celluloid or any other equivalent, nonbreakable, transparent material having its actual side-edges 11 and its actual end-edges 12 initially bowed in line parallel therewith, as shown particularly in Figs. 4 and 5. In other words, under my invention, the bowing of the edges is concerned with the thickness thereof and runs parallel therewith, as distinguished from crimping or heading the body of the crystal, within its ultimate edges in lines transverse thereto.

This crystal is adapted in length and width to fit within a retaining-flange 13 produced by turning inwardly thefforward edge of an oblong, rectangular, sheet-metal case 14 receiving a marine movement of any approved 7 standard construction and generallydesignated by the numeral 15. The said movement 15 has secured to it an oblong rectangular dial-plate 16 and a corresponding back-plate 17, the movement and plates forming the movement-unit of our improved clock. The twoplates 16 and17 are adapted in size to snugly fit within the case 14, so, that, when the movement-unit is inserted into the case 14 from the rear thereof, the sideand end-edges of the dial-plate 16 will engage with the rear faces of the corresponding initially-bowed edges of the yielding, nonbreakable crystal 10 aforesaid.

' The said movement-unit is held in place by means of retaining-blocks 18, held in engagement with the rear face of the end-edges of the back-plate 17 by screws 19 passing transversely through the case 14, which, withthe said blocks and screws, forms the case-unit of our improved clock.

The parts described are so proportioned thatwhen the movement-unit is properly positioned within the case-unit, the opposite faces of the initially-bowed-edges 1111 and 12-12 of the convex, celluloid crystal 10 will be so firmly clamped between the retainingfiange 13 of the case 14 and the sideand endedges of the dial-plate 16, that they will be measurably straightened out and form an effective yielding joint of a compensatory character, so that any inequalities in the thickness or bowing of the crystal, or varia-- tions in the positioning of the movementunitin the case-unit will be compensated for, making the clock convenient to assemble and independent of exacting accuracy of con struction. The rattling of the crystal, common to clocks having glass crystals, is also entirely eliminated, and also any rattling of the movement-unit in the case-unit.

Furthermore, the breakage of the crystal,

due to blows which would ordinarily result edges initially. bowed out of a common plane, I

so that when such edges are placed under tension from their opposite faces, they will be brought substantially into a common plane, whereby the case-unit and the movement-unit of the clock in which the said crystal is placed will be stabilized in their relative positions by .the effeort of the said bowed edges of the crystal to resume their initially-bowed form.

2. A resilient polygonal crystal having its actual edges'initially bowed out of a common lane in a direction arallel with the said e ges, 'sothat when suc edges are placed under tension from their 0 posite faces, they will be brought substantia ly in'toa common plane, where y the case-unit and the 'movement-unit of the clock in which the said or stal is placed will be stabilized in their re a.

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