US2191976A - Clock - Google Patents

Description

Feb. 27, 1940. E. E. TALIAFERRO 2,191,976

CLOCK Filed April '7, 1934 2 Sheets-Sheet 1 INVENTOR dwar'd 1 l 1 20 I V '1 I I ATTORNEY Feb. 27, 1940. AF R 2,191,976

CLOCK Filed April '7, 1934 2 Sheets-Sheet 2 lllllll Patented Feb. 27, 1949 UNITED STATES PATENT oFFicE 33 Ciaiins,

This invention relates to electric clocks and has for its principal object the provision of an improved carry-over or auxiliary movement for driving the time indicating means in case of failure of the current.

An object of the invention is to provide a.

unitary carry-over that can be removed from m in cost. If desired, the clock may perform, its

normal function while the auxiliary is being repaired, that is, the clock owner may remove the secondary or auxiliary movement and take it for repairs without losing the use of his clock. A particular object of this invention is to provide an auxiliary unit in which the spring motor of the auxiliary is kept wound up at all times by the electric motor of the clock.

Another object of the invention consists in the provision of silent means responsive to the motor current of an electric clock for positively and certainly starting and stopping the auxiliary movement. Altho responsive to the motor current, which is usually alternating current, my improved starter is practically silent as it does not produce the objectionable A. C. hum so noticeable in even the most expensive electric clocks now on the market. In carrying out this object of my invention I provide a freely pivoted armature to one side of and so spaced from the attracting pole that it cannot make contact with the pole whereby the direction of pull on the armature is almost a straight line thru the pivoting axis. In other Words, no spring or stops are used to limit or affect the motion of the armature when magnetized so that its motion.

and position are entirely controlled by the combination of the magnetic pull, which is more or less fluctuating, and the pull of gravity which is constant. The reason this eliminates chattering and hum is believed to be the fact that any fluctuating of the magnetic pull merely causesthe armature to swing thru a small are about the pivot. The pull on the pivot is substan* tially constant so that any tendency of the pivot to vibrate is small and this is probably damped out by the slight frictional forces set up in the oscillation of the armature on its pivot.

Still another object of the invention consists in providing an auxiliary movement for an electric clock in which the movement is carried in a frame pivoted in the main frame of the clock and is roclzed out of driving position by means driven by the main motor. In my copending (Cl. BS-26) application, Serial No. 530,053, 'filed April 14, 1931, now Patent l lo. 2,072,609 dated March 2, 1937, the rocking frame is moved by an electroinagnet connected to the motor circuit, and thus is moved into and out of driving position whether 5' or not the electric motor starts upon receiving current; in the present case the auxiliary movement is not disconnect-ed from the time indicating means until after the electric motor actually begins to drive these means whereby if [or sorne reason the main motor iaiis to'start er is slow in starting, the auxiliary movement continues to drive the clock hands at the correct in other words the arrangement is such that the simultaneous drive by both motors does not affect thecorrect of the hands and this is true even the the starting speed of the electric motor shouid fluctuate over a Wide range as is often the case during severe storms when the supply comes on and goes off at very close intervals several times during the disturbance. I

Still another object of this invention is the provision of means for preventing the initial hesitation or locking of the gears in case the con- 2 tact gear of the auxiliary movement should fail to mesh properly with the primary or electric motor driven train when rocked into winding or driving position.

Another object of the invention is the provision of ratchet or one way clutches between the spring motor of the auxiliary movement and the electric motor and also between the time. indicating train and the spring motor driven train, no friction connection being used. A furtherobject is .ie provision of the shortest pos sible normally stationary auxiliary train for driving the time indicating train upon failure or current; this object is carried out by driving the continuously operating time indicating train by a gear carried on the main shaft of the spring motor when a spring motor is used for operating the auxiliary movement. 7

Other objects oi the invention will be pointed out in the attached claims.

In the drawings-- Figure 1 is a front View of the clock with the casing removed.

Figure 2 is a rear View showing the auxiliary in winding position. 50

Figure 3 is like Figure 2 but shows the auxiliary in driving position.

Figure i is a side view.

Figures 5 to 9 are detail views.

Figure 10 is a modification.

Figures 11 to 14 are detail views of the modified form.

The frame H! of the auxiliary movement is carried by pivots H-ll in the main frame l2 which main frame also carries a synchronous electric motor I4 in driving relation with a motor or primary train consisting of a first wheel l5 geared to the rotor pinion It, a second wheel l8, a third wheel 20 and a fourth wheel 2i, all connected in the usual manner as bythe pinions 22, 23 and 24 on the arbors of the respective wheels. It is apparent that the number of gear wheels may be changed as desired and also that the gear ratio may be changed as required by the speed of the synchronous motor selected. On the arbor 25 of the fourth wheel 2| of the electric motor train is a pinion 26 which is adapted to mesh with the Winding wheel 21 of the spring motor winding train when the secondary frame iii is rocked in a counterclockwise direction (Figure 2) by downward movement of link 28 which movement is caused by the motor 14 operating thru mechanism to be described farther along. One of the supporting pivots ll of the auxiliary movement is journaled in the bracket 30 (see Figure 10) which bracket is removably secured to the main frame as by means of screws 3|; this mounting permits the easy removal of the auxiliary movement for repairs or replacement as for this purpose it requires in addition to the manipulation of screws 3| only the disconnection of link 28 at 32 and the unhooking of the spring 33.

As Will be seen in Figures 1, 2 and 3 the auxiliary movement, for purposes of definition, may be said to consist of three trains, namely, a winding train through which power is delivered to the spring motor; a spring motor driven or secondary train through which the spring motor drives the time indicating train and finally the time train which includes the escapement and by which the spring motor speed is controlled. The winding train consists of the previously mentioned winding wheel 21 and gears 34, 35, and 36. When driven the wheel 21, thru pinion 34 drives wheel 35 and thereby turns the motor barrel wheel 36 to wind the spring and store energy therein; in order to prevent overwinding of the spring a slip device of any known type is provided at any desired point either in the electric motor train or in the spring winding train, e. g., at 2| (Figure 5) or in the spring barrel 38. The spring is connected to drive the main arbor or shaft 40 on which is rigidly mounted the main wheel 4| of the time train which wheel meshes with the pinion 42 on the second wheel 43 of the time train which in turn meshes with the pinion M of the third wheel 45 and the turning of this wheel is controlled by the escapement lever 46 and the balance wheel 41, the last element of the time train. There is also carried on the shaft 40 What I term the connecting wheel 43 which is adapted to mesh with and drive wheel 50 of the time indicating train whenever the frame In is rocked in a clockwise direction by the spring 33. Altho in Figure 2 I have shown the spring 33 connected to the top of the frame [0 and to bracket 5| exterior of the main frame, it is to be understood that it may be located at any satisfactory point within the main frame. The Wheel 48, and the arbor 40 constitute the secondary or spring motor train, since it is through these two elements that power is delivered to the time indicating train from the spring motor;

for

Referring particularly to Figures 1 and i it will be seen that the pinion 52 on shaft 53 of wheel 50 is in mesh with the minute time wheel 54 of the time indicating train which in turn thru its pinion 56 drives the time wheel. E8. The hour wheel iii] which is driven from the pinion iii of the time wheel 53 carries a hub 62 for supporting the hour hand 63. The minute hand 65 is carried by the minute wheel hub 66 which serves as an axle for the hour wheel hub; the pinion 24 fast on the shaft 67 which projects thru the minute wheel hub or sleeve 66 for carrying a seconds hand 88. It will be seen that the time indicating or dial traizris really a part of the spring driven clock train altho during normal electric operation it is disconnected therefrom. Stated in other words, the normal spring motor train is separated into two parts, one part comprising the spring motor and the other part comprising the time indicating train which includes gear 59 and pinions E52 and 2'2! in addition to the usual dial train. This differs from the prior practice in which a complete clock train was used as an auxiliary, i. e., the

only gears common to the main train and the auxiliary train in the prior art were the gears of the dial train; thus the oil on the relatively long spring driven train, which train remains stationary most of the time, became gummy and sticky and often prevented the spring motor from starting. By making the effective length of the stationary train shorter, the sticky oil, being on only half as many gears, never has a sufficient total retarding effect to prevent the spring motor train from instantly starting and driving the time indicating train. It will be appreciated that the winding Wheel ill and the gears connecting it with the spring motor are in motion during the winding operation but are stationary during the running of the spring motor.

The electric motor train drives the time indicating train by means of a one-way clutch or coupling shown schematically in Figures 4 and 5 as a pinion ll] loosely carried on shaft 25 and having ratchet teeth adapted to engage with a set of similar teeth on a collar 'l" l fixed to the shaft 25; the pinion 7G is urged into engagement with the collar by some yielding means such as a li ht spring 12 around the shaft and compressed between pinion l0 and the previously mentioned pinion 23. This pinion 16 is loose on shaft 25 but the collar or clutch ii is fast on this same shaft as is the fourth wheel 2| of the electric motor train, connecting thru pinion 24. If the electric motor should stop any reason such as the disconnection of the motor conductors 13 from the supply or failure of the supply the secondary would take up the driving of the clock hands but because of the one-way clutch or coupling represented by the pinion and collar just described, the elec tric motor train would not be driven since the teeth of the pinion ii) would ratchet over those on the collar ll without turning the shaft.

The link 28, best shown in Figure 9, is a reversed L-shaped member having a slot "it at its upper end for receiving a post 32 on the frame it! of the secondary which post is normally held slot and. pin connection 11, "which gives the pinion lost motion with respect to the shaft 25 (seeFigure 5).,

A book '59 is provided at the elbow of the link for engaging a holding pin-80 on the main frame and on the left edge of the upright stem there is provided a cam surface 8i for engaging a camming pin 82 and thereby guiding the link into hooking engagement with the holding pin 80 as the link is moved downward by means of the pin 83 on the clockwise turning disk 84 (Figure '7) which pin engages a shoulder 85 on the same edge of the link. As the pin 83 moves off the shoulder it engages a second camming surface 86'which assists in moving the link to the right and into engagement with the holding pin.

The left end of the horizontal portion of the link-is provided with a downturned lug or extension: 81' for engagingthe tripping pin 88 carried by the arm 89 fixed to the shaft 90 which is pivotedin the main frame. The shaft also carries an armature Sl at the end of an arm 92 and a third-arm 93 located between the other two and likewise fixed to the shaft. The arm 82 or the arm 93 may be connected to the shaft thru a lost motion'device of the type shown in Figure 5 in order that the armature in dropping will attain sufficient impetus to kick the link to the left to move the'hook 19 from under the pin 80; however, where the tripping pin 88 is spaced from the portion 81 when the link is in holding position, alost motion connection is unnecessary.

The link 28 is operatedby means of the above mentioned pin 83 on the disk 84 carried at the end of the shaft 94 of the wheel l8 and pinion '23. As best shown in Figures 6 and 7 the disk 34 haslimited rotation with respect to the shaft, being resiliently connected thereto by the spring 95 on a second disk 91 fixed to the shaft and at the other end to the pin 98 in the disk 84. A slot 99"(Figure 8) in disk 91 accommodates the pin 83 and an elongated notch I00 in the edge of disk 84 accommodates the pin 96. The disk 84. is held on the hub of disk 91 by a pin I8l and a washer I02. It will be noted from an inspection of Figures 6, 7 and 8 that the pin I0! also serves to secure disk 91 to the shaft; this is due to the fact that the disk 91 is provided with a hub which extends thru and carries disk 1 El i-and has areduced portion for the washer I02 which reduced portion has a transverse bore for receiving the pin IEH. A'stirrup bracket I03 prevents the arm 2B from moving out of position.

The operation of the preferred form will be made clear by reference to Figures 1, 2 and 3. In Figures 1 and 2 the secondary train is in normal position, that is, the locked position taken when the motor Mis energized and driving the time train. Should the motor current fail or the plug 108 be pulled from the supply outlet, the armature 9 I would drop and thus cause the tripping pin 88 to strike portion 81 of the link and move it to the left to release hook 19 from the holding pin 80. Should the pin 83 be in interfering position at this time, the pin I04 on wheel 18 will engage the arm 83 and prevent the armature from falling until the pin 83 has passed out of the way; the motor M continues to revolve a few revolutions after the current is stopped time driving the wheel 18 the necessary distance to free the arm 93. When the link is released the auxiliary movement is rocked in aclockwise direction (Figure 2) by the spring 33. This rocking movement disconnects the winding wheel 21 from the pinion 26 and then meshes wheel 48 with wheel 50 of the time train but also during this rocking movement the balance wheel 41 is given a spinning impulse by being dragged along and out of engagement with the spring clip l0"! fixed to the main frame. Thus the secondary movement is positively started and continues the driving of the hands of the clock whenever the current is interrupted; as has been stated the seconds hand 68 is stationary at this time since it is carried by the arbor G'lwhich is a part of the now stationary synchronous motor train. Whenin motion the synchronousv motor train includes not only gears 2h; 2| and 2B but may be said to include certain gears of the secondary movement namely the gears of the winding train, 26, 2'1, 34, 35, and 36, which are always stationary when the motor M is stopped and which are driven by the motor I4 during normal electric operation of the clock unless of course the slip clutch is located in wheel 2! in which case the winding train becomes stationary as soon as the spring motor is fully wound.

When the motor l4-is again energized the armature 8| is drawn up into alinement with a segment 105 of the motor field core and the shaft 98'. It will be noted that the armature does not engage the core or any stop member but is suspended free of any parts except the shaft thus eliminating all possibility of an A. C. hum at this point. The reason for this is probably due to the osci. ation of the armature on its pivot whereby sufficient friction is set up to dampen the audible vibration. The raising of the armature merely moves the trip pin 88 out of the way of the lug 81 of the link 28 thus permitting the link to be moved by pin 83 into holding engagement with the pin 80. The motor may make several revolutions before bringing the pin Shinto engagement with the shoulder 85 on the link but there is no interruption to the movement of the hands because the auxiliary continues to drive until rocked out of mesh by the downward movement of the link 28. Thus during a change over period the hands are driven by both the auxiliary movement and the motor and the hands never change speed even for a fraction of a second. This is also true when the change is from electric to spring drive for the reason that the motor has sufiicient inertia to drive the hands during the moment between the stopping of the current and the unlatching and starting of the auxiliary movement which takes much less time than the reverse movement just described.

Thefact that the rocking frame is positively locked in Winding position while the motor is energized absolutely prevents any A. C. hum or chatter that might otherwise occur if the spring 33 were working against a fluctuating yielding force such as that exerted by an electro-magnet or the field force of the motor. I have discovered that any appreciable spring pull or other yielding. force against the pull of an A. C. armature will cause the armature to vibrate and if the armature rests against a metal surface this vibration will produce a very noticeable hum. For this reason I have arranged the mechanism as described so that as soon as the hook 19 engages the holding pin 80 there is no longer a yielding magnetic pull against the force of the spring 33 and also the tripping armature 9| does not rest against a surface while energized.

In Figures 10 to 14 I have shown a modification in which the link, bell crank, etc., are

all dispensed with and the secondary unit is stationary with respect to the main frame and at all times in mesh with both of the gears 26 and 50. In place of the spring clip I01 I provide' a resilient stop motion arm H0 for starting and stopping the balance wheel, which arm is fixed to a cuif III freely mounted on shaft H2 pivoted in the main frame I2. An armature H4 is fastened on the shaft H2 by means of disk I I 5 which is spaced from the arm I I0 with which it is connected by means of a lost motion device consisting of a disk H5 fixed to the rotatable cuif III which disk is slotted at H6 to receive a pin II! on the armature carrying disk H5. The notch or slot H6 is wide with respect to the pin II'I so that when the armature I I4 drops from the full line position in Figure 10 to the dotted line position it has considerable impetus before the pin II'I' strikes the disk so that the stop motion arm III} is kicked rather suddenly from under one side of the balance wheel to the other thereby to spin the wheel and make certain the starting of the secondary. The counterweight I20 on the side of the disk H5 prevents the arm end iIB from swinging back against the balance wheel 41 while the current is cut off and the armature H4 hangs as shown in Figure 13.

When the motor is again energized the armature I I 4 is attracted by and raised toward the field pole I35, the pin II'I strikes the lower edge of the slot or notch H6 and moves the disk H5 suddenly in a clockwise direction. The horizontal end H3 of the arm H0 is snapped against and moves entirely under the rim of the balance wheel and then because of the slot and pin connection II6-II'I moves entirely out of engagement with the rim. But the weight I20 brings the arm back and causes the horizontal end H8 to rest against and stop the balance. An extension IEI is provided at the end of the armature to act as a pilot so that the armature proper may be pulled across a wider gap.

The modification in Figure 10 requires that a one-way clutch connection be substituted for the pinion 52 in order that the wheel 50 may remain stationary while the electric motor is driving the time train. In Figure 12 is shown the clutch pinion 52' provided with ratchet teeth which engage corresponding teeth on the clutch end or collar I22 fixed to the shaft I23 of the wheel 50. The pinion 52. is urged toward the collar by the spring I24 compressed between the pinion and the wheel 50. It is to be understood that the coupling It, II on shaft 25 is employed in this modification exactly as in the preferred modification and it functions in the same manner, the only difierence being that the pinion 25 is at all times in mesh with the winding wheel 21. Altho the secondary train in this modification is always in mesh with the primary, I still prefer to mount it in a separate secondary frame it as in the modification in Figure l, the only difference being that the frame pivots Ii are journaled in lower journals, one of which-is shown at I25. Thus the sec-- ondary is removable as a unit just as in the modification shown in Figure 1. The operation of the invention as shown in Figure 10 is apparent and will not be described further than to point out again that during driving of the dial train by the spring motor, the synchronous motor train being stationary, the coupling 10, II shown in Figure 5 overruns or idles.

In Figures 13 and 14 the starting armature H4 is shown as held by a leaf spring I30 against movement toward the motor in order to prevent the spring motor train from being stopped if the electric motor fails to start immediately upon receiving current. However, as soon as the motor starts it causes the wheel I5 to drive the wheel I32 and thereby to carry the pin I33 around to engage and move the spring I30 downward out of latching position to release the armature II i and allow it to swing up adjacent the pole I35 of the motor. This last movement of the armature stops the spring motor driven train as above described. Upon the motor becoming deenergized the armature II I swings downward against the comparatively weak spring I30 over the end of which it easily slides and by which it is prevented from a return movement until the spring is moved out of locking position by the turning of the electric motor train, as already described.

It will be noted that in the modifications in Figures 10 to 13 the armature I I4 does not engage the pole I 35 but lies in a straight line between this pole and the pivoting shaft II 2 so that most vibration of the armature is damped and what is not damped is inaudible since it is not transmitted to any sounding element.

Referring again to Figures 2, 3 and 4 attention is called particularly to the upright arm 93 of the bell crank 00, 92, 93 and the pin I04 which elements have an important function not mentioned above because it is one performed rarely, that is, when the supply voltage fluctuates par ticularly during electric storms. The dying down of the voltage and current allows the armature iii to drop but the motor I4 will not necessarily stop because as is well known a synchronous motor will continue to keep in step with the frequency even tho the voltage drops a great deal and maintains a surprising torque under these conditions. The dropping of the armature SI releases and starts the auxiliary movement as already described so we have the situation where both motors are driving the hands. This situation however, has no detrimental effect since the speed of the hands is not affected to any appreciable extent which is a great advantage over some dual drive clocks now on the market which seem to drive the hands at double speed during the time that both drives are operating. While the voltage remains at a low value the motor I4 continues to assist in driving the hands. However, the field magnetism is not strong enough to attract the armature 9| across the relatively wide gap. But in the meantime the pin I04 has traveled around into engagement with arm Q3 which causes the armature 9| to rise close enough to be attracted by the field pole. The secondary unit is then pulled out of driving engagement by operation of the pin 83 on the link 28 in the manner described above. It will thus be seen that the arm 93 and the pin I 04 cooperate to move the armature into the infiu ence of the weakened motor field thus acting to stop the secondary during periods of low voltage; it is to be understood of course that the auxiliary movement would be intermittently started and stopped as long as the fluctuating low voltage period lasts. It is obvious that the movement of the armature into the weakened field could be used to actuate a starting device as well or to actuate any other mechanism.

I also find it advantageous in some cases to make the armature 9| somewhat too heavy to be attracted from its lower gravity position by the normal motor field so that it stays in its lower position even after the motor is energized and until movement adjacent the attracting pole by operation of pin Hi l on the arm 93. This has two desirable results, one being that the spring motor will always continue to drive the clock hands a few seconds after the electric motor takes up the drive and another result being that the heavier armature will make more certain the kicking of the latch 19 from under the holding pin 80. These two results may be accomplished also by spacing the armature 9i too far from the pole N15 to be attracted by the normal motor field.

Although my invention relates primarily to the improvement of electric clocks by the addition of a novel means for connecting an auxiliary carry-over unit to drive the clock hands, it is to be understood that the invention is not limited to carry-overs but includes auxiliary gear trains for any use as it will be apparent that the auxiliary might well have any known clock function other than the driving of the hands during current failure.

What I claim is:

1. In a clock having a first train of gears and a motor for driving the same, a second train of gears, an energy storing device included in said second train, means for coupling said trains together and gear actuated means driven by the first gear train for actuating said coupling means, whereby operation of the motor causes operation of the first gear train and operation of the first gear train then causes operation of the gear actuated means which in turn causes the coupling together of the two trains thereby causing energy to be transmitted from the motor through said trains to said device.

2. In a clock, an electric motor driven gear train, a second gear train, yielding means normally urging said second gear train out of driving engagement with said motor driven gear train, means operated by said motor driven gear train to overcome said yielding means and connect said trains, and means actuated by de energization of the motor for releasing said connecting means.

3. In a clock, a first gear train, a second gear train, an electric motor for driving the first gear train, means for driving the second gear train, means responsive toenergization of the motor for stopping the second gear train, means preventing the operation of the stopping means and means actuated by thefirst gear train for rendering the preventing means inoperative.

i. In a clock, a first gear train, an electric motor for driving said train, a second gear train, a motor for driving the second gear train, means including an armature adjacent the electric motor for stopping the second gear train, means for holding the stopping means in inoperative position, means actuated by the first gear train for releasing said holding means whereby the sec-- ond gear train stopped after the gears in the first train begin to turn.

5. In a clock, a first gear train, a second gear train, an electric motor for driving the first gear train, a motor for driving the second gear train, a pivoted lever biased to hang in an inoperative position, in which position one end is adjacent the second train, an armature on said lever located within the effective influence of the stray field of said electric motor, means for holding the lever in said inoperative position and and means operated by the first train for releasing said holding means, whereby when the motor is started the gears of the first train rotate to release said holding means, thus permitting the stray magnetic field of the motor to attract the armature thereby to turn the lever on its pivot from said inoperative position and. cause said one end to engage and stop said second gear train and whereby upon failure of motor current the armature swings again to move the lever to its inoperative position out of stopping engagement with said second train.

6. In a clock, a main frame, a motor and a train of gears driven thereby mounted in said frame, an auxiliary frame movably mounted in said main frame, an auxiliary gear train carried by said auxiliary frame, a gear in said first mentioned train adapted to engage a gear in th auxiliary train thereby to limit the movement of said auxiliary frame in the main frame, and means operated by the turning of said motor for moving said auxiliary frame to bring said gears into mesh.

'7. The device of claim 6 in which a yielding means is provided for normally urging said auxiliary frame to disengage said gears.

8. The device of claim 6 in which said means includes a yielding link for preventing the locking oi the gears.

9. The device of claim 6 in which said means includes a. link connected to said auxiliary frame, a lever for actuating said link, and means connected to be moved by a gear of said motor driven train for engaging said link to move said auxiliary frame.

10. The device of claim 6 in which a latch is provided for holding said gears in mesh.

11. In a clock, an electric motor, a first gear train driven by the motor, a second gear train, a frame for said second gear train movably mounted with respect to the first gear train, yielding means for moving said second gear train into engagement with the first gear train, a link for moving said second gear train out of engagement with the first gear train, a member driven by a gear of the first gear train, said link being shiftable into and out of the path of said member, means for locking the link out of said path, a pivoted armature adapted to be energized, raised and held by the motor current, and adapted upon failure of said current to drop and thereby to shift said link into said path so that the resumption of flow of current and the resultant turning of the motor driven gear train causes said member to move the link thereby to move the second gear train out of engagement with the first gear train.

12. In a clock having time indicating means, an electric motor for normally driving said means, a secondary motor for driving said means upon failure of the current to the electric motor, an escapement control for governing the speed of the secondary motor, an arm for frictionally engaging and stopping said control, a weight loose- 1y connected to said arm and held out of equilibrium by the electric motor when energized and adapted to swing into equilibrium upon deenergization of the motor thereby to suddenly drag the arm along and out of engagement with said control to initiate its motion.

13. The device of claim 12 in which the loose connection between the arm and weight contains a lost motion mechanism.

14:. In an electric clock, a time train, a synchronous motor for normally driving said train, a main frame comprising front and back plates for supporting said train and motor, a unitary carry-over device for driving said train during interruptions of motor current, said device including an auxiliary frame removably mounted between said front and back plates, a trunnion carried by one of said frames and journaled in the other for supporting one side of said device, and means for supporting the other side of said device, said means including a bracket and releasable means for securing the same to one of said plates whereby loosening of the securing means permits the removal of the carry-over device from the main frame as a unit.

15. In a clock, a time indicating train, an electric motor for normally driving said train, an escapement controlled spring motor having a main driving gear, coupling means for connecting said driving gear directly with a gear of the time indicating train for driving the same, mechanism positioned by the electric motor current for normally preventing operation of the spring motor, means cooperating with said mechanism for locking said coupling means in inoperative position and armature means actuated by dying down of the motor field for releasing said locking means.

16. In a clock comprising a main frame having front and back plates, a primary movement mounted between said plates in the usual manner, an auxiliary unit comprising a secondary frame having front and back plates, a movement in the secondary frame, and means for removably mounting the auxiliary unit within the main frame with said movements in operabl proximity, said means including a bracket removably secured to the plate of one of the frames, said bracket having a journal connection with the proximate plate of the other frame whereby upon loosening of the bracket the auxiliary unit may be removed from the main frame without disturbing the primary movement.

17. In a clock, a synchronous electric motor adapted to be actuated by the alternating current from a commercial lighting system, a time indicating means, driving means connecting said motor and said time indicating means, a disengageab-le coupling means forming a part of said driving means, mechanical timing means, auxiliary coupling means for connecting said mechanical timing means to said time indicating means to drive the same, an energy storage device for moving said auxiliary coupling means into operative engagement, latch means for holding said auxiliary coupling means out of engagement, means driven by the motor for storing energy in said energy storage device and latching the auxiliary coupling means out of engagement and low voltage responsive means for releasing said latch upon the failure of motor current whereby the energy storage device causes the reengagement of said coupling means upon interruption of motor current or upon lowering of the lighting system voltage.

18. A timing device comprising time indicating means, a constant speed electric motor for driving the same, a coupling means between said means and the motor for permitting operation of the time indicating means independent of the motor, a constant speed auxiliary driving means, a disengageable coupling means spring pressed to connect the auxiliary driving means to drive the time indicating means, latch mechanism for locking the disengageable coupling means out of engagement, means driven by the electric motor for operating said latch mechanism to move and lock the disengageable coupling means out of engagement and means responsive to failure of motor current for releasing said latch mechanism whereby upon failure of motor current the auxiliary driving means drives the time indicating means.

19. In a clock, a dial train, a time controlled spring motor, a synchronous motor and synchronous motor driven train, an overrunning clutch between the last train and the dial train for permitting operation of the dial train inde pendently of said last train, coupling means spring-pressed to connect the spring motor to drive the dial train, a latch for locking said coupling means out of connecting relation, mechanism adapted to be driven by the synchronous motor for moving the coupling means out of connecting engagement and into engagement with said latch whereby the spring motor is locked out of driving relation with the dial train, and a low voltage responsive means for releasing said latch to cause the engagement of the spring motor and dial train upon failure of motor current or upon dropping of the supply voltage to which the motor may be connected.

20. In a continuous drive electric clock having time indicating means, an electric motor and an escapement controlled mechanical timing means for driving the time indicating means during failure of electric current to the motor: the combination of a pivoted armature for causing the starting of said mechanical timing means upon failure of current to the electric clock, said armature having a position out of the effective influence of a magnetic field in the clock, and means operated by the electric motor for moving the armature from said position to a position where it may be effectively acted on by the magnetic field to be moved thereby to a position spaced from said first mentioned position, means for returning the armature to said first mentioned position upon failure of said magnetic field and means actuated by said armature in its return movement for starting the mechanical timing means.

21. The device of claim 19 in which the armature is too heavy to be moved from said first mentioned position by the magnetic field.

22. In an electric clock, a dial train, a synchronous motor for driving said train, an auxiliary means for driving the dial train upon failure of current to the motor, a pivoted armature normally held by the magnetic field of the motor and adapted to swing to and stop in a position out of the effective influence of the field upon failure of motor current, means actuated by the armature as it swings out of said field of effective influence for starting the auxiliary means, and means driven by the motor for mechanically moving said armature into the effective influence of said field whereby the armature is again held by the field.

23. In a clock, a time indicating means, a motor for driving said means, an escapement control for governing the speed of said motor, said control including a balance wheel, means for giving a spinning impulse to said balance wheel including an arm pivoted to resiliently sweep against the rim of said balance wheel in a manner to give a turning impulse to the wheel, means for moving the arm to sweep said rim, said moving means being adapted to swing the arm in the reverse direction to stop the wheel, the arc of the stopping swing being sufficient to move the arm out of engagement with the rim of the wheel and means including a lost motion connection between the arm and said moving means whereby after passing out of contact with the rim the arm stops and swings back into engagement with the rim and stops the wheel.

24. In an electric device having an element to be moved, a pivot, an unbalanced armature mounted to turn on said pivot to move said element, said armature being biased to a chosen position of equilibrium to which it returns when tie-energized, alternating current magnetic means spaced from the pivot for energizing and there by actuating the armature from said position to move and hold said element, whereby any fluctuation of the magnetic pull of said magnetic means causes the armature to oscillate on the pivot thereby damping out audible A. C. hum.

25. The combination of claim 24 in which a lost motion connection is provided between the armature and said element thereby preventing said oscillation from being transmitted to the element.

26. In an electric clock having a main frame and a dial train mounted therein, an electric motor mounted in said frame for normally driving said dial train, a carry-over unit including a gear operably connected to drive the dial train, said unit having on each of two sides a journal connection with the main frame and means for loosening one of said connections whereby the unit may be bodily lifted from said frame without disturbing the normal operation of the clock.

27. In a continuous drive electric clock having time indicating means, an electric motor and an escapement controlled mechanical timing means for driving the time indicating means during failure of electric current to the motor: the combination of control means for preventing op eration of said mechanical timing means during normal electric operation of the clock and for releasing said mechanical timing means upon substantial fluctuation of electric power to the motor, said control means including a pivoted armature which. under the action of gravity has a position of equilibrium out of the effective zone of said magnetic field, means operated by the electric motor for moving the armature from said position into said zone where it may be effectively acted on by the magnetic field to be moved thereby to a position further spaced from said position of equilibrium, said armature adapted to drop by gravity back to said position of equilibrium upon substantial failure of said magnetic field whereby causing said control means to again release said mechanical timing means.

28. In a continuous drive electric clock hav ing time indicating means, an electric motor and an escapement controlled mechanical timing means for driving the time indicating means during failure of electric current to the motor: the combination of control means for stopping said mechanical timing means during normal operation of the electric clock, said control means including a pivoted armature, said armature normally being inoperatively associated with a magnetic field in the clock during failure of electric current to the motor and means operated by the electric motor for moving the armature to a position where it may be effectively acted on by the magnetic field to be moved thereby to a position spaced from its inoperative position and means for returning said armature back to said inoperative position upon failure of said magnetic field whereby said control means again releases said mechanical timing means.

29. An electric clock including in combination an electric motor, a driven mechanism normally driven by said motor, an auxiliary movement for alternatively driving said mechanism, stopping means for the movement, means for releasing the stopping means upon failure of power supply to the motor and means for restoring the stopping means by operation of the motor.

30., An electric clock including in combination a synchronous motor, a hand mechanism normally driven by said motor, a spring movement having a balance wheel, means for alternatively driving said hand mechanism from either the motor or movement, stopping means including a brake adapted to engage the balance wheel to stop the movement, means including a spring for disengaging the brake and balance wheel upon failure of power supply and means for reengaging the brake and balance wheel by operation of the motor.

31. In a continuous drive electric clock having time indicating means, an electric motor and an escapement controlled mechanical timing means for driving the time indicating means during failure of electric current to the motor; the combination of control means including a brake normally engaging the escapement and thereby stopping said mechanical timing means during normal operation of the electric clock, said control means also including a pivoted armature biased to a brake releasing position but normally held from said position by a magnetic field in the clock during normal electric operation of the clock whereby upon substantial failure of said magnetic field the armature releases said brake, and means for restoring the control means to normal condition in which condition the brake stops the mechanical timing means and the armature is held by the magnetic field, said restoring means in the initial portion of each restoring action being actuated by operation of the electric motor as distinguished from actuation by mere energization of the motor, whereby when in response to substantial failure of current the control means releases the mechanical timing means for driving the time indicating means, the mechanical timing means operates not only for the duration of each such failure but continues to operate for an appreciable period of time after the electric motor begins normal operation.

32. An electric clock including in combination an electric motor, a driven mechanism normally driven by said motor, an auxiliary movement for alternatively driving said mechanism, stopping means for the movement, means for releasing the stopping means upon substantial failure of power supply to the motor and delayed action means for restoring the stopping means, the initial step in the restoring action of said restoring means being always by operation of the motor as distinguished from mere energization of the motor whereby the auxiliary movement continues to operate for an appreciable period of time after each restoration of power to the motor and until stopped by actual operation of the motor.

33. In an electric clock, a first gear train and an electric motor for driving the train, a second gear train and means for driving the second gear train, magnetically controlled brake means normally held in a braking position for preventing operation of the second gear train, said brake means being biased to move directly from its braking'position to off position upon each failure of a magnetic field in the clock thereby to permit operation of the second gear train, and restoring means for moving the brake means from its off position to its braking position, the initial step in each restoring action of said restoring means being by operation of the first gear train, said brake means always remaining in said off position until started therefrom by operation of the first gear train as recited, whereby the brake means cannot be moved by the restoring means to said braking position except by operation of the first gear train and whereby the second gear train continues to operate after each failure of the magnetic field until stopped by operation of the first gear train.

EDWARD E. TALIAFERRO.

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