US2987929A - Juhas - Google Patents

Description

June 13, 1961 Jul-[As 2,987,929

DRIVE MECHANISM FOR TIME RECORDERS Filed Dec. 14, 1956 2 Sheets-Sheet l f@ IO U, I;

,5 21 l n if 7 a i 23,. rfif June 13, 1961 M. JUHAS 2,987,929 DRIVE MECHANISM FOR TIME RECORDERS Filed Dec. 14, 1956 2 Sheets-Sheet 2 Ize/Qreifsr Michae gufzas esillililiililI 1. 1

United States Patent Time Corporation, New York, NY, a corporation of Delaware Filed Dec. 14, 1956, Ser. No. 628,447 17 Claims. (Cl. 74-40) The invention relates to an improved drive mechanism for time recorders and comparable machines employing recording or indicating elements that require periodic progressive adjustment in accurately timed incremental steps.

The drive mechanism constituting the present invention is particularly well adapted, although not limited, to the timed periodic actuation or setting of the type wheels commonly provided in recorders for printing time records. One object of the invention is to provide an improved drive mechanism that maintains the type wheels effectively locked against accidental movement in either direction between successive adjusting steps.

A more specific object is to provide drive means for a pawl and ratchet mechanism which imparts quick and positive steps to the ratchet wheel while maintaining the wheel effectively locked against movement by the steps.

Another object is to provide a time cont-rolled drive mechanism which is eflicient and positive in action yet of such simple and rugged construction that it is adapted to give troublefree service for long periods with a minimum of attention.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawings in which:

FIGURE 1 is a perspective view of the type carriage subassembly of a recorder equipped with drive mechanism embodying the features of the invention. 7 a FIG. 2 is a fragmentary sectional view of the lower portion of the assembly taken in a plane substantially on the line 22 of FIG. 1.

FIG. 2A is a fragmentary side view showing details of thepawl and ratchet mechanism for actuating the type wheels of the recorder.

FIG. 3 is an exploded perspective view of the drive mechanism.

FIG. 4 is. a fragmentary elevational view of the drive mechanism showing the actuating lever as having just completed its stroke in one direction.

FIG. 5 is a view similar to FIG. 4 showing the 'drive shaft rotated 90 from the position shown in FIG. 4."

.FIG. 6 is another fragmentary elevational view similar to the preceding tated another 90 pleted itsstroke in the opposite direction. v

Whilejja preferred form of the invention has been shown and will be described herein, there is no intention to limit thefinvention either to the particular construcrecorder. I On the contrary, the intention is to cover ,all modifications and adaptations falling within the spirit and scope of the invention as expressed in the appended claims.

h For purposes of illustration the improved drive mechanism has been shown as incorporated in animand-out time recorder of the general type disclosed in the patent.

to Long, No. 2,209,409, issued July 30, 1940. This time recorder has the usual time printing device 10 on atype carriage 11 slidably supported on transversely disposed guide bars 12 carried between the side walls 13 of a sheet metal frame 14. The printing device comprises aseries of type wheels' 15 driven in well-known manner figures but showing the drive shaft roand the actuating lever as having com-- tion illustratedor to use with any particulartype of mounted ice by a Geneva gear 16 mounted on a common shaft with the drive wheels so that the printing indicia on the wheels are maintained in synchronized position with respect to a clock or other time indicating device. In the particular recorder shown the Geneva gear 16 is driven by a pinion (not shown) slidable on a square shaft 17 journalled at opposite ends on the frame plates 13.

Shaft 17 is adapted to be rotatably driven step-by-step by a pawl and ratchet mechanism comprising a pawl 18 cooperating with a toothed ratchet wheel 19 fixed at one end of the shaft 17. The pawl, as shown, comprises a pair of elongated metal strips secured together in spaced relation by a cross pin 20 adapted to engage the teeth of the ratchet wheel 19 as the pawl reciprocates. At its opposite end the pawl is pivotally mounted on the projecting end of a bar 21 constituting one side member of a rock frame. The other side member of the frame comprises a bar 22, the two bars being connected by rigid end members 23. The end members 23 are apertured centrally for the reception of a pivot pin 24 which has its opposite ends reduced in diameter and journalled in bearings 25 carried on the frame plates 13.

Reverse movement of the ratchet wheel during retraction of the pawl in successive operating strokes is prevented by a dog 26 pivoted on the side plate 13 adjacent the ratchet wheel as at 27. The dog carries a latch pin 28 engageable with the teeth of the ratchet wheel. A spring 29 connected between the pawl and the dog urge both into engagement with the ratchet wheel but yield to permit the step-by-step rotation of the wheel as the pawl is alternately retracted and advanced by the swinging of the rock frame. A stop 30 determines the limit of pawl advance.

The action of the pawl and ratchet mechanism is such that with the pawl in either the advanced or retracted position, the teeth of the ratchet wheel are engaged by the cross pin 20 and the dog pin 28 so that the wheel is effectively locked against accidental movement in either direction. During the retracting movement of the pawl, only the dog pin maintains its engagement with the ratchet teeth and consequently the ratchet wheel is subject to inadvertent movement by excessive vibration, jarring or other accidentally applied force.

Such improper operation is precluded when the printing wheels of the recorder above described are actuated or set by the drive mechanism constituting the present invention. With that mechanism, the actuation is effected in quickly executed, positive steps so that the printing wheels are effectively locked substantially all of the time against accidental movement in either direction. More particularly, engagement of both the pawl and dog with the ratchet teeth is interrupted only momentarily as the pawl is advanced or retracted.

The drive mechanism includes a suitable source of power such asa motor M of the type used for timing purposes which may be either spring or electrically driven. The motor shown is an electric motor arranged to drive a shaft 35 (FIG. 2) through reduction gearing enclosed in a gear housing 36. It will be understood, of course, that the'gearing, which is conventional, is arranged to provide a predetermined desired shaft speed for timing the ratchet stepping action. Thus, when utilized for driving printing Wheels of the type which record time, a shaft speed of one revolution per minute will impart an adjusting step to the wheels in each minute. Other rates of adjustment may be employed, of course, if desired. In the exemplary recorder the motor M is mounted on the lower portion of the frame 14 with the axis of the shaft 35 disposed at right angles to the pivotal axis of the rock frame.

In the preferred form shown, the drive mechanism includes an actuating lever 37 pivoted at one end on a stud 38 secured to the name 14 at one side of the motor shaft and substantially in horizontal alignment with it. As will be seen by reference to FIG. 3, the stud 38 serves to space the lever 37 substantially from the supporting frame so that the lever swings about an axis parallel to the axis of the shaft and across the end of the shaft. A rigid link 40 operatively connects the actuating lever 37 with the rock frame whereby the latter is rocked about its pivot to reciprocate the pawl 18 in response to the swinging of the lever about its pivot 38. Thus, when the lever is swung upwardly or clockwise, as viewed in FIG. 1, the rock frame is rocked in a direction to retract the pawl 18 and shift it into engagement with the next adjacent ratchet tooth. Upon downward swinging of the lever 37, the frame is rocked in the opposite direction to advance the pawl and impart a rotational step to the ratchet wheel 19 and the shaft 17 to which it is fixed.

' While the operative connections of the link 40 with the associated parts might be effected in any preferred manner, in the particular embodiment illustrated, a pivoting pin 41 connects the lower end of the link 40 to the actuating lever. Rearwardly bent cars 42 adjacent the upper end of the link are slotted to embrace circumferentially grooved sections of the frame bar 22 and thus provide a pivotal connection with the frame. The grooved sections of the bar are located, of course, so as to maintain the link upright at all times.

- In accordance with the invention provision is made for biasing the actuating lever 37 to swing alternately in opposite directions in timed relation to the rotation of the timing shaft 35 and in direct response to such rotation. Provision is also made for positively restraining the actuating lever against movement by the biasing force applied to it except in predetermined positions of the timing shaft in which the lever is permitted to snap over from a position at one side of the shaft to a position at the opposite side. Thus, the timing shaft not only furnishes the power for swinging the actuating lever and thereby setting the printing wheels but it also times those movements precisely with respect to shaft rotation.

The biasing and control of the actuating lever is effected through the medium of a control element 45 nonrotatably mounted on the end of the shaft 35 adjacent the lever. The control element is conveniently formed with a cylindrical body 46 centrally apertured to receive the shaft and having a set screw or other suitable means for looking it to the shaft. At its outer end, the body 46 is reduced in diameter to present a hub or cylindrical projec-v tion 47 concentrically aligned with the shaft 35.

For biasing the actuating lever a spring anchorage in the form of an arm 48 is rigidly secured to and rotatable with the control element 45. The arm 48 projects radially from the element and its outer end is bent over at right angles to extend into proximity with the lever 37 and provide an anchorage for one end of a tension spring 49. The other end of the spring is secured to a stud 50 rigid with and projecting from the actuating lever 37 adjacent its free end. The spring 49 is selected to provide a desired tension or bias on the lever and to store sufiicient power for operating the ratchet mechanism to advance the printing wheels.

-It will be evident that in the rotation of the timing shaft and control element 45, the anchorage for the spring 49 will rotate in a path that carries it from one side of the pivotal axis of the lever to the other side. Accordingly, when the control element is in the position shown in FIG. 4, the'spring anchorage is located above the pivotal axis of the lever and the lever is accordingly biased upwardly. The bias shifts to the opposite direction as the element 1'0- tates through the position shown in FIG. and reaches its maximum in a downward direction as the element approaches the position shown in FIG. 6.

. 1 As mentioned heretofore, movement of the actuating lever 37 by the biasing force applied through the spring 49 is restrained in all except selected positions of the 4 shaft. Such restraint is imposed by extending the end of the stud 50 to define a follower 51 adapted to ride on the peripheral surface of the hub 47 of the control element. To release the lever for movement at preselected times, the hub is formed with a diametrically disposed slot 52 dimensioned to afiord clearance for the follower. Preferably the follower portion of the stud is reduced in diameter and the slot 52 correspondingly narrowed so that the major portion of the hub surface is effective for restraining movement of the lever.

Preferably the slot 52 is aligned with reference to the spring anchorage or arm 48 so that it is presented for entry of the follower 51 as the arm approaches a vertical position either above or below the axis of the timing shaft. The actuating lever is thus released for movement substantially at the instant that the biasing force of the spring reaches its maximum value. All of the power expended in the tensioning of the spring is therefore utilized for executing the stepping action. Also frictional resistance to the movement of the follower through the slot is minimized, permitting the actuating lever to snap over from one side of the timing shaft to the other substantially instantaneously.

It will be apparent from the foregoing that the invention provides a time controlled drive mechanism adapted to periodically adjust or step a printing wheel or comparable recording element while effectively maintaining the element locked against accidental or inadvertent movement between steps. The mechanism is simple in construction and inexpensive to produce. Its simplicity and durability insure along, useful life. Moreover, its mode of operation reduces wear and simplifies maintenance.

Also this mechanism is especially adaptable for use with low torque motors because of the small power requirement. The motor has only to extend the spring connected to the follower which rides on the small diameter hub less than 50% of the time, thereby reducing the friction to a minimum.

I claim as my invention:

1. In a re'corder having a mechanism adapted to be adjusted step-by-step, in combination, a motor, a control element rotatable by said motor at a predetermined uniform speed, a lever pivoted at one side of said element, means actuated by said control element in its rotation for biasing said lever to swing first in one direction and then in the opposite direction about its pivot, said 'control element having means normally operable in its rotation restraining said lever from movement by said biasing means and adapted to release the lever for movement only in predetermined positions of the element, and means op erable incident to the swinging of said lever for imparting an adjusting step to the mechanism.

2. In a mechanism adapted to be actuated step-bystep, in combination, amotor, acontrol element rotatable by said motor at a predetermined uniform speed, a lever pivoted at one side of the rotational axis of said element, a spring anchorage rotatable by said element in 'a path that alternately passes above and below the pivot of said lever, a spring connected between the leverage and said anchorage operative to bias the lever for swinging first in one direction and then in the other direction incident to the rotation of the anchorage, and means onsaid lever coacting with means on said control element normally restraining the lever against movement in either direction and acting to release the lever for swinging in predetermined positions of the control element, and means operable incident to the swinging of'said lever for actuating the mechanism.

3. In a mechanism adapted to be actuated step-by-step, 1n combination, a motor, a control element rotatable by said motor at a predetermined uniform speed, a lever pivoted at one side of the rotational axis of said element, a spring anchorage rotatable by said .element in a path that alternately passes above and below the pivot of said lever, a spring connected between the leverage and said anchorage operative to bias the lever for swinging first in one direction and then in the other direction incident to the rotation of the anchorage, a hub on said control element presenting a cylindrical surface, a follower on said lever adapted to ride on the hub surface and restrain the lever against movement in either direction by said spring, said hub having a diametrical slot affording clearance for said follower to permit swinging of the lever in predetermined positions of the control element, and means operable by the lever in such swinging for actuating the mechanism.

4. In a mechanism adapted to be actuated step-bystep, in combination, a motor, a control element rotatable by said motor at a predetermined uniform speed, a lever pivoted at one side of the rotational axis of said element, a spring anchorage rotatable by said element in a path that alternately passes above and below the pivot of said lever, a spring connected between the leverage and said anchorage operative to bias the lever for swinging first in one direction and then in the other direction incident to the rotation of the anchorage, a hub on said control element presenting a cylindrical surface, a follower on said lever adapted to ride on the hub surface and restrain the lever against movement in either direction by said spring, said hub having a diametrical slot affording clearance for said follower, said slot being alined with said spring anchorage so that the lever is released for swinging movement as the biasing force of said spring approaches maximum values, and means operable by said lever for actuating the mechanism.

5. A drive mechanism for a recorder having a settable time recording element adapted to be advanced in incremental steps, a pivoted lever operable when swung about its pivot to impart a step to the settable element, a biasing spring secured at one end to said lever and at the other end to an anchorage shiftable alternately between positions above and below the pivotal axis of said lever, and means for restraining movement of the lever by said biasing spring, said restraining means being operative to release the lever for movement at predetermined intervals.

6. In a time recorder having a series of type wheels and a pawl and ratchet mechanism for actuating the type wheels, drive mechanism operative to reciprocate the pawl for imparting rotative steps to said. pawl for actuating the type Wheels comprising, in combination, a rotatably driven cylindrical element, an arm rigid with and projecting radially of said element, a lever pivoted at one end at one side of said element with its free end positioned to swing across the end of the element, a spring connected between the arm and the lever effective to bias said arm for movement first in one direction and then in the other direction as the arm rot-ates, said element having a diametrically extending slot in its end face, and a follower on said lever engageable with the peripheral surface of said element to restrain the lever from swinging until said slot is positioned to receive said follower.

7. In a time recorder having a series of type wheels and a pawl and ratchet mechanism for actuating the type wheels, drive mechanism operative to reciprocate the pawl for imparting rotative steps to said pawl for actuating the type wheels comprising, in combination, a rotatably driven element, a lever pivoted at one end with its free end positioned to swing across the end of said element, a follower on said lever positioned to ride on the peripheral surface of said element, said element having a diametrically disposed slot affording clearance for said follower to permit the lever to swing across the element in either of two positions of the element, a spring connected between said lever and a shiftable anchorage, and means operable in the rotation of said element for shifting said anchorage to condition said spring for rocking the lever first in one 6 direction and then in the other in synchronism with the rotation of the element.

8. The combination with a pawl and ratchet mechanism, drive mechanism operative to reciprocate the pawl for imparting rotative steps to the associated ratchet cornprising, in combination, a motor driven shaft, a cyhndrical element concentric with said shaft and rotatable with it, an actuating lever having one end pivotally supported at one side of said shaft, a follower at the other end of said lever positioned to ride on the periphery of said element, an arm projecting laterally from said element and rotatable with the element, a tension spring connected between said arm and said other end of the lever yieldably urging said follower against the element, said element having a diametrically disposed slot affording clearance for said follower to permit said lever to be swung across the element by said spring twice in each revolution of the element, and a link operatively connecting said lever with the pawl.

9. The combination with a pawl and ratchet mechanism, drive mechanism operative to reciprocate the pawl for imparting rotative steps to the associated ratchet comprising, in combination, a motor driven shaft, a cylindrical element concentric with said shaft and rotatable with it, a lever pivoted at one side of said shaft with its free end positioned to swing across the end of said element, said element having a diametrically disposed slot in its end face, a follower on said lever positioned to ride on the peripheral surface of said element and prevent the swinging of the lever until said slot is presented for the entry of the follower, an arm extending radially from and rotatable with said element, a spring connected between said arm and said lever, said spring being alined with said slot and effective to swing the lever first in one direction and then in the other direction as said slot is presented for the entry of said follower incident to the rotation of said element, and a link operatively connecting said lever with the pawl.

10. A snap acting mechanism comprising a rotatable element having an axis of rotation, a pivoted lever adapted to have one end describe a path of movement through said axis of rotation, a resilient energy storing member connected to said rotatable element and said pivoted lever and adapted to move said end of said pivoted lever along said path in a snap acting manner, and means movable conjointly with said rotatable element adapted to be movable into said path to restrain movement of said pivoted lever for a discreet period of time, said restraining means being movable out of said path upon completion of said period of time to permit motion of said end of said lever along said path.

11. A snap acting mechanism comprising a rotatable element having an axis of rotation, a pivoted lever adapted to have one end describe a path of movement through said axis of rotation, a resilient energy storing member connected to said rotatable element and said pivoted lever and adapted to move said end of said pivoted lever along said path in a snap acting manner, and an arcuate bearing surface means movable conjointly with said rotatable element radially disposed with respect to said axis of rotation and adapted to move across said path for a discreet period of time to restrain said pivoted lever, said bearing surface means being movable out of said path upon completion of said period of time to permit motion of said end of said lever along said path.

12. A snap acting mechanism comprising a rotatable shaft, a substantially rigid member secured to said shaft for rotation therewith, a pivoted lever adapted to have one end thereof describe a path of movement across the end of said shaft, resilient means connected to said pivoted lever and said rigid member and adapted to move said end of said pivoted lever along said path in a snap acting manner, and an extending arcuate surface bearing means formed in the end of said shaft subtended by a plane parallel to the axis of said shaft, said surface bearing means being movable across said path for a discreet period of time to restrain said pivoted lever and movable out of said path upon completion of said period of time to permit motion of said end of said lever along said path.

13. A snap acting mechanism comprising a rotatable shaft having a cutaway portion in one end of said shaft, an extending arcuate surface adjacent said cutaway portion subtended by a plane parallel to the axis of said shaft, a pivoted lever adapted to selectively bear upon said arcuate surface and to move through said cutaway portion, a rigid member mounted on said shaft for rotation therewith, a resilient member connecting said rigid member and said lever and adapted to impart snap action to said lever, said rigid member adapted to rotate said shaft whereby said arcuate surface and said cutaway portion are moved to successively restrain and release said pivoted lever.

14. An actuating mechanism of the double throw type comprising a rotatable element, a pivoted actuator operable along a path between two limiting positions relative to said element, resilient means connecting said element and said actuator whereby rotation of said element causes movement of said actuator between said positions, and restraining means movable conjointly with said element and adapted to alternately hold and release said actuator during movement thereof whereby said actuator is moved in a snap acting manner.

15. An actuating mechanism of the double throw type comprising a rotatable element including a shaft, a pivoted actuator operable relative to an end of said shaft along a path between two limiting positions, and resilient means connecting said element and said actuator whereby rotation of said shaft causes movement of said actuator between said positions, said shaft having an end adapted to have a restraining means capable of rotative movement into and out of said path to successively hold and release said actuator for operation in a snap acting manner.

16. An actuating mechanism of the double throw type comprising a rotatable element including a shaft having an end formed to present an axially extending bearing surface subtended by a plane parallel to the axis of rotation, a pivoted actuator operable between two limiting positions, said actuator having a follower portion thereon movable so as to describe a path in proximity to and across the end of said shaft; and resilient means conmeeting said element and said follower portion of said actuator whereby rotation of said' element causes said follower to move along said path between said limiting positions, said follower portion being alternately restrained and released by movement of said bearing surface across said path to effectuate snap operation of said actuator.

17. An actuating mechanism of the double throw type comprising a rotatable element including a shaft having an axial cutaway portion therein, a pivoted actuator operable between two limiting positions adapted to have a follower portion for engaging said shaft upon movement between said limiting positions, and resilient means connecting said rotatable element and said actuator whereby rotation of said shaft causes said actuator to move to said positions, said follower portion of said actuator alternately engaging said shaft and moving through said cutaway portion to thereby cause said actuator to operate in a snap acting manner.

References Cited in the file of this patent UNITED STATES PATENTS 552,647 Stahlberg Jan. 7, 1896 2,095,683 Watkins et al. Oct. 12, 1937 2,209,409 Long July 30, 1940 2,788,410 Terry Apr. 9, 1957

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