US2763121A - Horological mechanism - Google Patents

Description

Sept. 18, 1956 w. A. AYRES 2,763,121

HOROLOGICAL MECHANISM Filed June 1, 1950 I 3 Shets-Sheet l INVENTOR. WAL DZMAF ,4. ,4 YPAZS BY WMW A A TTo/PNE Y Sept. 18, 1956 w. A. AYRES' HOROLOGICAL MECHANISM 5 Sheets-Sheet 2 Filed June 1, 1950 INVENTOR. WADE/WP A. A YP A TTOENE Y Sept. 18, 1956 w. A. AYRES HOROLOGICAL MECHANISM 3 Sheets-Sheet 3 Filed June 1, 1950 NET;

INVENTOIR. MADE/WE A. A 7/4 55 ATTOE/VE).

United States Patent HOROLOGICAL MECHANISM Waldemar A. Ayres, Kew Gardens Hills, N. Y., assignor to Ayres Clock Company, Inc., Long Island City, N. Y., a corporation of New York Application June 1, 1950, Serial No. 165,427

2 Claims. (-Cl. 58-28) The present invention relates to time keeping and indicating devices and particularly to electrically driven clocks.

It is an object of the present invention to provide an electrically driven timepiece which employs a novel frequency generator.

It is a further object of the present invention to provide a clock energized by direct current requiring a very low current drain for operation.

It is another object of the present invention to provide a novel timepiece which obviates sliding friction in the frequency generator and eliminates fragile and sensitive jewel and staff elements.

A further object of the present invention is accomplished by a novel timepiece which does not require oiling of bearing surfaces.

Yet another object of the present invention is the provision of a timepiece that obviates the need for delicate balance spring elements.

It is a further object of the present invention to provide a clock having a unique and efficient magnetic drive for the indicator hands.

Another object of the present invention is the provision of a novel rate adjusting means for a unique frequency generator in a timepiece.

An additional object of the present invention is the provision in a timepiece of a frequency generator and separate magnetically energized power drive for the time indicator.

Further objects of the present invention are the provision of a timepiece wherein the frequency generator is not deprived of energy to drive the time indicating gear train and the provision of novel spring suspension means for the oscillating mass of the frequency generator.

Other objects and advantages of the present invention will become clear from a reading of the following specification in conjunction with the appended drawings, in which:

Fig. 1 is a schematic showing of one form of the novel timepiece of the present invention;

Fig. 2 is a fragmentary elevational view of a part of the cam and gear drive;

Fig. 3 is an elevational detail showing of the stepping magnet and cam shaft;

Fig. 4 is a rear elevational view of a clock with parts in section;

Fig. 5 is a sectional view taken along the line 5-5 of Fig. 4;

Fig. 6 is a detail showing, on enlarged scale, of the novel frequency generator of the clock shown in Figs. 4 and 5;

Figs. 7 and 8 are views, on an enlarged scale, showing the contactor and regulator assembly of the clock shown in Figs. 4 and 5; and

Figs. 9, 1 0 and 11 are detail showings of a second form of contactor and regulator assembly that is adapted for use in a clock of the type shown in Figs. 4 and 5.

The present invention is shown schematically in Fig. 1. Amoscillating. mass 10 comprising an arm 11 of non- 2,753,12i Patented Sept. 18, 1956 ice magnetic material such as brass has a central, laterally extending bore 12 and at one end a permanent magnet 13 and at its other end a weight 14 counterbalancing the magnet 13. The top center of arm 11 is tapped to receive aset screw 15. A helical spring 16 has its ends attached to frame members. One frame member 17 is shown and the other is omitted for clarity. Spring 16 passes through bore 12 and arm 11 is firmly secured to one of the spring convolutions by means of set screw 15.

Spring 16 also carries a collar 18 secured to the spring by means of a set screw 19 and welded or otherwise secured to collar 18 is a metal contact arm 20. The free end of contact arm 20 carries a small block 24 of insulating material such as fiber or the like which may be cemented to the upper face of contact arm 20.

Oscillating mass 10 and spring 16 form a frequency generator having a period that may be on the order of one-fifth to one-half second for ordinary timekeeping purposes. The period of this frequency generator may be regulated by means of the contact arm 20 as will be described.

A contact member 21 fiXed to the clock frame (not shown) breaks and makes contact with contact arm 20 during each oscillation cycle of frequency generator 10. A cam member 22 mounted to an adjustable shaft 23 mounted in the clock frame (not shown) can be rotated to adjust its clearance above insulating block 24. When mass 10 is put into oscillation, torsion is imparted to spring 16 so that as the mass 10 rocks counterclockwise, contact arm 26 is lifted from engagement with contact member 21 and as it rocks clockwise, contact arm 20 is swung back into engagement with contact member 21. Cam 22 is so placed that as contact arm 29 moves upwardly it engages cam 22 prior to the complete counterclockwise excursion of oscillating mass 10. While contact member 20 is moving upwardly and prior to block 24 striking cam 22, torsion is being distributed along the whole length of spring 16. When block 24 strikes cam 22 the portion of the spring between collar 18 and frame member 17, indicated as 16, is immobilized, that is spring 16 is effectively shortened leaving the stiffness of the remainder of the spring 16 as the factor determining the period of the oscillating mass. The ratio of the time during which the whole length of spring 16 is effective as compared to the time during which spring 16 minus section 16 is effective determines the overall stiffness of the torsion spring 16 and the relation of this overall stiffness to the oscillation mass 10 determines the period of the frequency generator. Since the gap between cam 22 and block 24 is adjustable then the above ratios are adjustable hence regulation is achieved by adjusting cam 22.

The clock of the present invention is electrically energized. A solenoid comprises a core 26 of iron or other magnetic material and a coil or winding 27 which is connected by lead 28 to one terminal of battery 29 and by lead 30 to frame member 17. The other terminal of battery 29 is connected to contact member 21 by way of leads 31, 32 and switch 33. When switch 33 is closed, current will flow through the above outlined circuit which includes frame 17, spring 16 and contact arm 20.

Contact arm 20 is secured to spring 16 in such position that with the system at rest contact arm 20 is closed against contact member 21. The electro-magnetic field of the solenoid is so related to the pole of bar magnet 13 closest to the solenoid that the oscillating mass 10 will be driven counterclockwise. Mass 10 is so poised on spring 16 that, with the system at rest, bar magnet 13 is near the upper end of its normal oscillatory motion.

it will be understood from the above description that upon closing switch 33, a magnetic field is set up by the solenoid, and bar magnet 13 will be driven downwardly;

that is, counterclockwise. The torsion thereby set up in spring 16 causes contact arm 20 to be lifted away from contact member 21. The magnetic field of the solenoid collapses, allowing the energy stored in spring 16 to swing magnet 13 clockwise and return contact arm 20 into engagement with contact member 21 whereupon the above oscillation cycle is repeated.

The timepiece of the present invention utilizes a novel magnetic indicator drive which will be now described.

A rock shaft, journaled in the clock frame, not shown, has mounted on one end a cylindrical cam 35, which will be described later, and at its other end a plate 36 having a sector cut away at 37. Projecting into this sector is a pin 38, mounted on the clock frame, not shown, so that shaft 34 is free to rock through the angle represented by sector 37. A bar magnet 39 is mounted to shaft 34. Cam 35 engages with a diamond toothed wheel or gear 40, which will be described later, so that upon rotation of shaft 34 through one cycle, first counterclockwise then clockwise, gear 40 is stepped or rotated by an amount equal to the angular distance between two diamond teeth 41. Gear 40 is mounted on a shaft 42 which carries a worm gear 43 in engagement with a worm wheel 44. Worm wheel 44 drives a shaft 45 which in turn drives a conventional gear train indicated generally at 46 and this gear train terminates in a conventional hour hand 47 and a conventional minute hand 48.

Mounted on the cover of winding 27 is a small permanent magnet 49. This magnet may be cemented in place and is so positioned adjacent the bar magnet 39 that the pole 50 of magnet 39 will be attracted toward pole 51 of magnet 49.

Pole 50 of magnet 39 is so related to the magnetic field set up by solenoid 26, 27 that magnet 39 is driven clockwise by repulsion due to the residual interaction between the two fields. With the system at rest and switch 33 open, magnet 39 is in the position shown in Fig. 1; that is, pole 50, attracted toward pole 51 of magnet 49 causes shaft 34 to be retained in its maximum counterclockwise position.

When switch 33 is closed, the magnetic field of the solenoid overcomes the lesser attractive force between poles t and 51, causing magnet 39 to be driven clockwise until stopped by the left hand shoulder of plate 36 striking pin 33. Upon decay of the soleonids magnetic field (caused by the lifting of contact arm 20 from contact member 21 as above described), the attractive force between poles 5t and 51 causes bar magnet 39 to be rocked counterclockwise again to the position shown. It will be clear, therefore, that for each oscillation cycle of the mass 10, shaft 34 will be rocked clockwise and counterclockwise one cycle, causing cam 35 to advance the gear 40 by the angular distance between two of the teeth 41.

In order to minimize arcing between contact arm 20 and contact member 21, a resistance R may be shunted across contact arm 20 and contact member 21.

The novel system above set forth is embodied in a clock as shown in Figs. 4 and 5.

Clock 60 has a square face plate 61 which carries conventional hour and minute indicia thereon. Parallel frame plates 62 and 63 are held in place rigidly by two screw studs 65 and 66 extending from the rear frame plate 62 through frame plate 63 and secured to face plate 61 by machine screws 67 tapped into the right hand ends (Fig. 5) of studs 65 and 66. Screw stud 66 carries a bracket 63 which is held tightly against the rear frame plate 62 by means of a threaded nut 69.

Bracket 68 has upper and lower right angle portions 70 and 71 which extend over and under the bobbin of winding 27 which may be secured thereto by nuts 72 threaded to tapped upper and lower extensions of solenoid core 26. The bottom portion of bracket 68 extends downwardly forming the base portion 73 for maintaining the clock upright in conjunction with the bottom. edge of face plate 61. v

Screw stud extends rearwardly of rear frame plate 63 and carries a U shaped plate 74 which is maintained in position by nut 75. Plate 74 is insulated from the remainder of the frame by an insulating bushing assembly 76. As shown in Fig. 4, plate 74 carries on its upper leg a disc cam 77 which is mounted to screw stud 78 which is mounted in a tapped hole of upper leg of plate 74. The lower leg of plate 74 carries an electrical contact member 79. Cam 77 has been omitted from Fig. 5 so that the contacting arm 36 may be shown with clarity. Figs. 7 and 8, however, clearly show the details of the relation between cam 77 and contact arm 80. This contact arm is a strip of metal having one end fixed to helical spring 81 by means of a collar 82 rigidly connected to contact arm 39 and a set screw 83 which passes through a tapped hole in the collar 82 into engagement with a convolution of spring 81. The other end of contact arm has cemented or otherwise fixed to its upper surface an insulating block 84 of fiber or the like and this latter end of contact arm 80 forms a contact surface on its under side engageable with contact member 79. Fig. 7 shows cam 77 spaced from its support, U shaped plate 74 by a spacer bushing 73 surrounding stud 78 and contact member 79 is struck laterally of plate 74. A screw stud 'or pillar 85 (Fig. 5) extends rearwardly from frame plate 63 to which it is secured by a machine screw 86 for the suspension of a helical spring 81 between frame plate 63 and a mounting lug 37 secured to pillar 85 by a threaded nut 88. Screw studs 89 and 90 have shank portions attached to the end convolutions of spring 81 and these convolutions are soldered or staked to said stud members. Stud 89 has an integral conical shoulder portion which mates with a conical shoulder formed in frame plate 63. The hole in frame plate 63 through which stud 89 projects is not tapped, and the threaded section can be freely drawn through the hole in assembly. Nut 91 will draw up conical shoulder 95 tightly into engagement with the mating shoulder of frame plate 63 to keep stud 39'and spring 31 from accidental rotation. A hole 96 is provided in the threaded section of stud 89 to receive an assembly tool.

Stud 96 has a threaded section in screw threaded engagement with lug 87, and nut 92 is screwed to stud 90 against a spring washer 94. The end of stud 90 is slotted at 93 to receive a screw driver for adjusting the tension of spring 31.

Oscillating arm 98 is mounted on spring 31 as shown in Fig. 6 by a set screw 99 engageable with a convolution of spring 81. Oscillating arm 98 includes the perma: nent magnet 16% which may be cemented in place and the counterweight 101 which may be likewise held in place or which may be integral with the bar member 93.

The magnetic drive as incorporated in the clock shown in Figs. 4 and 5 comprise-s the magnet 102 secured by cementing or otherwise to one leg 193 of a U shaped bracket 194 having its other leg 105 mounted securely to the rock shaft 106 which has its ends journaled in the frame plates 62 and 63.

Cylindrical cam member 107 is mounted near one end of rock shaft 106 and engages with the diamond toothed gear 108 mounted on a shaft 110, one end journaled in bracket 109 mounted to frame plate 63 and its other end journaled in a bracket 111, also mounted to frame plate 63. Shaft 110 carries the worm gear 112 which meshes with the teeth 118 of wheel 113. It was explained in the description of the schematic showing (Fig. 1) that the worm wheel drives a conventional clock gear train, hour and minute hands. In Figs. 4 and 5 the conventional gear train is represented by gears 114, the shafts are designated as 115, the minute hand as 116 and the hour hand as 117.

Permanent magnet 119 (Fig. 5) cemented to the cov ering of winding 27 is the equivalent of the magnet 49 shown in Fig. l and described above.

The cylindrical cam 107 shown in Fig. 5 is drawn in Figs. 2 and 3 on an enlarged scale. The cam itself is double acting; that is one section of the cam acts'to step a tooth 118 one-half of the total stepping distance as shaft 106 rocks in one direction and a second section of the cam acts to step the tooth the remaining half of the total stepping distance when shaft 106 rocks back in the opposite direction. The total stepping distance for such a rocking cycle is the distance between two adjacent teeth 118 of gear 108; that is, it is equal to the circular pitch of the gear 108, so that if there are twenty teeth 118 of gear 108 then in each cycle of clockwise and counterclockwise rocking of shaft 106, the gear 108 is stepped by onetwentieth of its circumference.

As shown in Figs. 2 and 3, cam 107 includes two spaced, cylindrically developed cam surfaces 120 and 121 secured to shaft 106. Cam surface 120 has a leading edge 122 extending angularly of the axis of shaft 106 and cam surface 121 has a leading edge 123 extending angularly of the axis of shaft 106 but facing in a direction opposite that of leading edge 122. Assuming that at the start of a cycle diamond tooth 118 is in the position of the right hand dotted tooth and that shaft 106 has just begun to rock clockwise as viewed from the right end of the shaft, leading edge 122 will engage tooth 118, camming it to the left until clockwise motion of shaft 106 ceases. Tooth 118 will then be in the position shown in full and it will dwell there (due to the frictional engagement of the worm 112 with wheel 113) until shaft 106, beginning to rock counterclockwise, will bring leading edge 123 into camming engagement with tooth 118 (as shown in Fig. 2), whereupon leading edge 123 cams tooth 118 into the left hand dotted position shown. As shaft 106 begins a second cycle by rocking clockwise, the next tooth 118 is engaged and advanced in the same manner.

It has been shown that contact arm 80 and cam 77 form a system for regulating the oscillating period of the frequency generator which includes spring 81, arm 98, magnet 100 and counterweight 101 carried by arm 98. Of course contact 80 together with contact member 79 also acts to make and break the electrical driving circuit periodically.

An alternate system for periodically making and breaking the driving circuit and also for regulating the period of the frequency generator is shown in Figs. 9, 10, and 11. An adjustable arm 126, mounted on stud 65 by machine screw 124 and spaced from frame plate 62 by a spacing washer 125, terminates in a bifurcated head member 127 having an insert 128 of insulating material such as fiber cemented to the top bifurcation. An arcuate contact arm 80' of spring metal such as spring steel passes through the slot 129 formed in the bifurcated head 127 and the slot has a width greater than the thickness of the contact arm 80. The lower bifurcation forms a contact member or surface 130 which is in the clock energizing circuit; arm 126 is electrically insulated from frame plate 62, however, by suitable insulation between screw 124 and arm 126 and frame 62 (not shown). This insulation may be similar to the bushing 76 shown in Fig. 5. Arcuate contact arm 80 has a radius equal to the distance of slot 129 from the axis of machine screw 124 so that arm 126 can be manually rotated in either direction about its position in Fig. 9 without affecting the ability of contact arm 80 and contact member 130 to make and break the electrical driving circuit satisfactorily. Contact arm 80' is welded or otherwise secured to a collar 82' which attaches to spring 81 by means of set screw 83' in the manner earlier set forth.

It will be clear that the flexibility of contact arm 80' will vary with the angular position of arm 126, so that the net period of the frequency generator can be shortened by rotating arm 126 counterclockwise (Fig. 9) and lengthened by rotating arm 126 clockwise. The spacing washer 125 affords sufficient frictional drag to arm 126 so that it will stay in the position to which it is manually adjusted.

The spring member 81 shown is made of spring strip 6 having a rectangular cross-section. It will be noted that the adjacent convolutions of spring 81 are spaced apart so that there is no energy loss due to sliding friction between convolutions. Fig. 5 shows an exaggerated spacing between convolutions. In practice the actual spacing may be considerably less.

It is within the scope of the present invention to use a spring of circular cross-section. The rectangular crosssection gives added stiffness which is desirable for certain applications.

Metal fatigue, which is a critical problem in conventional torsional devices, is minimized in the novel helical spring construction shown and described since the fatigue forces are distributed over a length of spring considerably greater than the distance between the spring supports.

By the present invention, sliding friction in the frequency generator is eliminated, and no lubrication of the generator is required. It is well recognized that in a conventional balance wheel and balance spring frequency generator, lubrication is essential and the period of a balance wheel and balance spring generator is critically affected by failure of lubrication and by the presence of too much oil at low temperatures.

It will be noted that the novel frequency generator shown and described serves no power function; that is, energy is not taken from the generator to drive the clock gears or to control an escapement. This results in increased stability of the frequency generated, which of course has a direct effect on the timekeeping accuracy of the clock, watch, fuse or other timer which may be constructed in accordance with the present invention.

The novel magnetic drive of the present invention is free of frictional losses inherent in mechanical drive and escapement systems and is much quieter in operation.

It will be understood from the above description that a number of changes may be made to the novel system as shown and/or described without exceeding the scope of the present invention.

The invention, therefore, is not to be limited by the foregoing description and the attached drawings, but solely by the scope of the appended claims.

What is claimed is:

1. In a time piece energized by direct current, a frequency generator comprising a torsion suspension comprising a resilient member under tension, a balanced mass mounted on said resilient member, circuit interrupting members including a fixed contact and a movable contact, said movable contact being secured to said resilient member and means for regulating the period of said frequency generator, said means including a member for varying the overall torsion of said resilient member.

2. A torsion pendulum comprising a spring member and an oscillating mass mounted thereon, a frequency regulating member attached to said spring member between said oscillating mass and a mounting of said spring member and means associated with said attached member for affecting the stiffness of said spring member through adjustable fractions of the arc of oscillation of said oscillating mass.

References Cited in the file of this patent UNITED STATES PATENTS 9,310 Terry Oct. 5, 1852 868,264 Guillaume Oct. 15, 1907 991,717 Grivolas May 9, 1911 1,683,648 Beasley Sept. 11, 1928 1,772,838 McEntire Aug. 12, 1930 2,084,657 Sears June 22, 1937 2,572,989 Contant Oct. 30, 1951 FOREIGN PATENTS 440,257 Great Britain Aug. 29, 1938 491,442 Great Britain Aug. 29, 1938 504,553 Great Britain Apr. 27, 1939

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