US2227133A - Escapement - Google Patents

Description

Dec. 31, 1940. H c HALL 2,227,133

ESCAPEMENT Filed May 7, 1940 INVENTOR ATTORNEY Patented Dec. 31, 1940 UNITED STATES ESCAPEMENT Barry C. Hall, Indianapolis, Ind., assignmto P. R.

Mallory A: 00., Inc., Indianapolis, Ind., a corl ration of Delaware Application May 7, 1940, Serial No. 333,130 2 Claims. (Cl. 24-112) This invention relates to rotary motion translating devices or escapements.

An object of the invention is to improve rotary motion translating devices or escapements.

Another object is to provide a device on gear drive means capable of delivering intermittent forward motion from a source of constant rotary motion.

Other objects of the invention will be apparent from the following description and accompanying drawing taken in connection with the appended claims.

The invention comprises the features of construction, combination of elements, arrangement of parts, and methods of manufacture and operation referred to above or which will be brought out and exemplified in the disclosure hereinafter set forth, including the illustrations in the draw- In the drawing:

Figure 1 is an end view with parts broken away of a gear train embodying an intermittent motion escapement mechanism according to one aspect of the present invention;

Figure 2 is a side view thereof;

Figure 3 is a detail view of a sliding bracket comprising part of the mechanism; and

Figures 4 and 5 are end and side views respectively of a gear member of modified form capable of substitution in the mechanism.

A feature of the invention resides in the combination with the gear train of an eccentrically driven sliding bracket or plate and a rotary escape arm intermittently advanced by the drive under control of the sliding bracket.

The invention is suitable, for example, for use in clock driven mechanisms for obtaining a periodic rapid advance of a driven member or shaft although the clock mechanism or clock motor rotates at a uniform relatively slow speed. Such rapid advance is useful, for example, in cam controlled electric contacts in order to effect rapid opening and closing of the contacts by the cams at the proper time and thereby prevent arcing during a period of uncertain contact pressure which would be present in the case of a steady slow forward movement of the cams controlling the contacts. One use of such clock driven cam switch arrangements is found in modern automatic home laundries and dish washing machines wherein the user sets the mechanism by turning a knob for a predetermined period of operation of the washing machine for washing, rinsing, etc.

While a preferred embodiment of the invention is described herein, it is contemplated that considerable variation may be made in the method of procedure and the construction of parts without departing from the spirit of the invention. In 5 the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring to the drawing, the casing [0 (Figure 2) contains a clock motor of either an electrical or mechanical type. Preferably the motor comprises a self-starting synchronous electric clock motor such as is commonly in use today in elec tric clocks of various types. Secured to one end of the casing I0 is an end plate II and spaced in front of plate II a short distance is a second similar plate l2, the plates being mounted and spaced apart by suitable bolts l3 and spacing sleeves H in a well-known manner. It is, of course, possible to have the drive motor situated at a more remote point and connected to the gear train by a flexible shaft or other suitable coupling.

The escapernent mechanism and its associated gears are mounted between plates H and [2. The driving pinion l5 mounted on shaft IQ of the clock motor drives large gear wheel ll mounted on shaft i8 extending between plates H and I2. Of course, additional gears may be interposed between the driving source and large gear I! to obtain the desired drive ratio. Gear wheel I! has secured to its rear face an eccentric cam I9, the cam being located between gear I! and plate II and rotating with gear H. In the same plane as eccentric cam I9 between gear l1 and plate II is also mounted a slide bracket 20 shown in detail in Figure 3. Slide plate 20 comprises a central transversely slotted portion 2| having a transverse slot 22 therein in which eccentric cam l9 travels. The two parallel sides of slot 22 bear against diametrically opposed edges of eccentric cam IS. The slide bracket 20 extends outwardly from both sides of slotted portion 2| in the same plane and near each of the projecting ends thus provided a longitudinal slot 23 is formed in the bracket, each of which slides on a pin 24 as the bracket is oscillated longitudinally by cam 19. An edge of each of the projecting ends of bracket l 20 is turned up at right angles to the plane of front face of large gear wheel ll.

It will be seen that as gear wheel I1 is slowly rotated by drive pinion IS the eccentric cam I3 will move sliding bracket 20 back and forth a short distance in a direction longitudinal to the bracket. Projecting ears 25 forming part of the bracket are thereby moved toward and away from the central region above the face of gear H, first one then the other of gears 25 approaching the center as the other recedes.

Mounted in front of gear wheel H to rotate on shaft 8 to which gear wheel I1 is affixed is an escape arm 26 and its associated gear 21. Escape arm 26 comprises a flat disc having a projecting arm integrally formed in its edge. The gear 21 is secured directly against the front face of escape arm 26 so as to rotate with it on shaft l8. A suitable hub or bushing is also preferably secured to the rear face of escape arm 26 to space it accurately from gear wheel H and provide a mandrel about which coil spring 28 may be wound. Coil spring 28 may be an ordinary coiled wire spring, one end of which is hooked over the rear edge of escape arm 26 as shown and the other end of which is hooked around a suitable pin 29 secured to the face of gear H.

The end of escape arm 26 is of such length that it will engage the innermost of projecting lugs 25 of sliding bracket 20 but will clear the outermost of the projecting lugs 25. Pin 29 extends above the face of gear i7 for a distance sufficient to engage arm 26 should gear ll be rotated while arm 26 is held in one position.

With coil spring 28 wound up as shown it will be noted that as gear rotates in a clockwise direction (as seen in Figure 1) escape arm 26 will also be drawn around in a clockwise direction by coil spring 28. Due to the tendency of coil spring 28 to unwind, arm 26 will be rotated to a position of engagement with the innermost of lugs 25 of the sliding bracket, at which position arm 26 will be halted in its forward movement. As gear ll continues to rotate, however, simultaneously tightening coil spring 28, sliding bracket 20 is being shifted by eccentric cam l9. Thus a point will be reached, somewhere within one half revolution of gear H, where escape arm 26 will be released by holding lug 25. When this occurs spring 28 will tend to rapidly rotate arm 26 in a clockwise direction until the arm engages the opposite lug 25 of the sliding bracket which will then be innermost. Arm 26 will then be halted while gear I! advances for degrees of its rotation, at which point escape arm 26 will again be released and rapidly moved ahead for another 180 degrees.

A gear member comprising a large gear 30 and a pinion 3| both secured to a shaft 32 is driven by gear 27 which is secured to the escape arm, gear 21 meshing with large gear 30. Pinion 3| extends through an opening in plate 12 but is protected by a suitable housing or shroud 33 which is open on one side to allow engagement with a driven gear such as gear 34 shown in Figure 2 secured to shaft 35 which may, for example, be a cam shaft of a cam operated switch or any other device driven by the clock mechanism.

Since gear 21 is affixed to escape arm 26 it will be apparent that gears 21, 36, 3| and 34 are all advanced intermittently at each half cycle of rotation of large gear IT. The angle of rotation of driven shaft 35 for each rapid advance period is determined by the ratio between the driven gears 21, 38, 3| and 34. It is obvious that fewer or more gears may be present in the driven gear train to meet special requirements or to vary the ratio. The period between intervals of rapid advance will be determined by the ratio between pinion drive l5 and large gear Additional gears may be interposed if desired to vary the ratio.

Should spring 28 become broken during operation of the device the mechanism will then operate as a constant slow speed advance. Pin 23 which is secured to gear I I will rotate until it engages the rear edge of arm 26, after which it will advance arm 26 and the driven gear train at a constant rate of speed. The pin 29 is so positioned on gear II with respect to eccentric cam I! that when it is in engagement with the rear edge of arm 26 the arm will be in the proper angular position to clear the lugs 25 as it rotates.

For some uses, such as for automatic home laundrles or washing machines, it is necessary to provide for manual adjustment of the cam shaft 36 controlling the electric contacts. For making this adjustment with the gear arrangement shown in Figures 1 and 2 the shaft 35, on the end of which is secured a suitable manual control knob, is pulled outward until gear 34 disengages pinion gear 3|, after which the manual adjustment can readily be made. When manual adjustment is completed the shaft 35 is pushed back to bring gear 34 again into engagement with pinion gear 3|. However, should the gears not be in a position to mesh at the instant shaft 35 is pushed back spring 36 affords a means for bringing the gears again into engagement. This operates as follows: Gears 30 and 3| are capable of sliding longitudinally on shaft 32 but the gears are normally held in the position shown by small coil compression spring 36 surrounding shaft 32. However, should cam shaft 35 suddenly be pushed back when gears 34 and 3| are not in meshing position, the gears 30 and 3| are moved back against the compression spring 36. Upon subsequent advance of the gears by release of escape arm 26 pinion gear 3| will be brought into mesh with gear 34 by spring 36.

Figures 4 and 5 illustrate a can be substituted for gears 30 and 3| and associated shaft 32 in some cases. This gear member comprises a large gear 40 corresponding to gear 30 and a small pinion gear 4| corresponding to pinion 3| of the previous figures. Gears 40 and 4| are not, in this case, rigidly secured together, however, but pinion 4| is free to rotate on shaft 42 which is secured to large gear 40. A pair of leaf springs 43 are secured to the face of gear 40 as shown with their free ends projecting to positions of engagement on opposite sides of pinion 4|. It will be evident that as gear member which ,gear 40 is rotated in a counterclockwise direction, as seen in Figure 4, pinion 4| is positively advanced with gear 40. Should pinion 4| be separately rotated in a counterclockwise direction, however, by turning the knob connected to cam shaft 35 the leaf springs 43 will snap over the gear teeth and allow it to be advanced in this direction. In this case it is not necessary to draw gear 34 out of engagement with pinion gear 4| before making the manual adjustment. The control knob can be rotated in only one direction in this case, however. In some cases, to insure maximum protection of the gear train and drive the two safety means may be combined in a single structure. This permits manual adjustment either with or without first unmeshing the gears.

While the present invention, as to its objects and advantages, has been described herein as carried out in specific embodiments thereof, it is not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimed is:

1. A rotary motion translating device comprisign a drive gear rotating at substantially uniform angular speed, an eccentric cam rotated therewith on the same axis, a driven gear co- ,axial with said drive gear and having a projecting latch arm thereon, a coil spring driving connection between said gears and encirclin their common axis, the ends of said spring being connected respectively to said drive gear and driven gear to provide a yielding driving connection therebetween, a flat bodied sliding bracket having a transverse slot therein engaging said cam whereby said bracket is oscillated thereby, said bracket being in the same plane as said cam and having a pair of upstanding stop arms thereon extending to diametrically opposite sides of the path of travel of the free end of said latch arm, said stop arms alternately 2. A rotary motion translating device comprising a drive gear rotating at substantially uniform angular speed, an eccentric cam secured against a face of said drive gear to rotate therewith, a driven gear mounted on the same shaft as said drive gear and having an outwardly projecting latch arm secured thereto, one of said gears being free to rotate with respect to said shaft, said driven gear being on the opposite side of said drive gear from said cam, a coil spring driving connection between said gears and encircling said shaft, the ends of said spring being connected respectively to said drive gear and driven gear to provide a yielding driving connection therebetween, a sliding plate having a transverse slot therein engaging said cam whereby said plate is oscillated thereby, said plate having a pair of upstanding stop arms thereon positioned on diametrically opposite sides of said shaft outside the periphery of said drive gear, said arms projecting to the periphcry of the path of travel of said latch arm and alternately moving into and out of said path of travel during oscillation of said bracket, whereby said driven gear is advanced intermittently for substantially 180 degrees at a time at intervals measured by substantially 180 degrees of rotation of said drive gear.

HARRY C. HALL.

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