US2142341A - Switch for electric drives for calculating machines - Google Patents

Description

Jan. 3, 1939. c. H. ARNOLD 2,142,341

SWITCH FOR ELECTRIC DRIVES FOR CALCULATING MACHINES Filed NOV. 10, 1953 5 Sheets-Sheet 1 gum T01 Charles H. Arnold Jan. 3, 1939. c. H. ARNOLD 2,142,341

SWITCH FOR ELECTRIC DRIVES FOR CALCULATING MACHINES Filed Nov. 10, 1933 5 Sheets-Sheet 2 mentoz Ch arles; H. Arnold Hi; (1301 M1 Jan. 3, 1939. c H, ARNOLD 2,142,341

SWITCH FOR ELECTRIC DRIVES FOR CALCULATING MACHINES v Filed Nov. 10, 1933 5 Sheets-Sheet 3 FIG. 4

T 'l' I63 C. H. ARNOLD Jan. 3, 1939.

SWITCH FOR ELECTRIC DRIVES FOR CALCULATING MACHINES FIG.6-

gnwmtoz Charles H. Arnold Jan. 3, 1939. c. H. ARNOLD 2,142,341

SWITCH FOR ELECTRIC DRIVES FOR CALCULATING MACHINES Filed Nov. 10, 1955 5 Sheets-Sheet 5 Charles H. Arnold Patented Jan. 3,1939

UNITED STATES PATENT OFFICE SWITCg FOR.

ELECTRIC DRIVES FOB ALCULATING MACHINES Application November 10, 1933, Serial No. 697,449

8 Claims. (01. 200-92) This invention relates to starting and stopping mechanism for electric motors used to drive calculating machines and the like.

Heretofore common parctice has been to use a constantly running motor for operating calculating machines. This was essentially true in cases where the calculating machine was equipped with a. traveling carriage adapted to be automatically returned to starting position by the same motor used to Operate the machine. The use of a start-stop motor no doubt has been retarded because of the difliculty in providing proper control of such a motor so that machine operations. and carriage return operations, would not interfere with each other.

In other words a start-stop motor must becontrolled in such a way that the calculating mechanism, and the carriage return mechanism, may be operated independently or in conjunction with each other, and in addition the motor must be so controlled that overlapping operations of either kind will not interfere in any way with the proper functioning of the machine. To accomplish this result'required the development of novel switch controlling mechanism which is embodied in the instant invention and which is to be presently described.

The advantages of a start-stop motor over a constantly running motor may readily be seen and appreciated. For example, in busy ofllces where the calculating machine is in constant use the greater part of the day, the operating motor for this machine necessarily runs continuously most of the day with the possible exception of lunch time, provided the operator does not .forget to turn it off at this time. This is irrespective of the fact that over half of the operators time is consumed in setting up various data upon the machine keyboard and in inserting and removing ledger or data sheets. From this will be deduced that the motor operates at least twice as much, or over twice as long a period, as is necessary, thereby consuming an unnecessary amount of electrical current and causing undue wear to the motor and its parts.

Motors of this kind are constructed to operate practically noiselessly, consequently it is not unusual for the operator to leave the motor running at the end of the day's work or during a lunch period, not knowing that it has not been switched oil, with the resulting waste in electrical current and unnecessary wear of moving parts.

Therefore, it is the main object of this invention to provide calculating and like machines with tion.

Another object of this invention is to provide suitable clutch mechanism for the start-stop motor.

Another object is to provide a novel non-repeat mechanism for the start-stop motor.

Still another object is to supply a unique speed regulating device for the start-stop motor.

A further object is to furnish an escapement device for controlling the motor switch during carriage return operations.

A still further object is to provide a slippage member for operating the escapement device.

Another object is to provide a novel return gear and clutch mechanism for the traveling carriage.

With these and incidental objects in view, the invention consists of certain novel features of construction and combinations of parts, the essential elements of which are set forth in appended claims and a preferred form of embodiment of which is hereinafter described with reference to the drawings which accompany and form part of this specification.

Of said drawings:

Fig. l is a side elevation as observed from the right of the machine showing the complete motor, the mechanism for releasing the motor during machine operations, and the mechanism for driving the carriage return gear.

Fig. 2 is a cross-sectional view of the motor, showing among other things the clutch for operatively connecting the motor to the machine driving mechanism and the speed controlling mechanism.

Fig. 3 is a plan view of the speed controlling mechanism.

Fig. 4 is a view of the clutch and switch mechanism.

Fig. 5 is a top plan view of the mechanism shown in Figs. 4 and 6.

Fig. 6 shows the mechanism for controlling the motor switch during traveling carriage return operations.

Fig. '7 is a disassembled perspective view of the escapement mechanism that controls the motor switch during traveling carriage return operations.

Fig. 8 is a sectional view of the friction drive member for operating the escapement mechanism shown in Figs. 6 and 7.

l Fig. 9 is a perspective view of a part of the carriage return mechanism.

Fig. 10 is a detail view of the carriage return gear mechanism and its associated rack as viewed from the rear of the machine.

GENERAL Dasoarr'rron The improved electric motor comprising this invention is shown applied to the well known Ellis model calculating machine which is illustrated and described in Letters Patent of the United States Nos. 1,197,276 and 1,197,278 issued September 5, 1916, to Halcolm Ellis, and Patent No. 1,819,084 issued August 18, 1931, to Emil J. Ens. The instant motor has a clutch arrangement for driving the machine mechanism which is similar to that shown and described in Letters Patent of the United StataesNo. 1,144,418, issued I to Kettering and Chryst June 29, 1915.

Releasing the machine for operation by depressing the motor bar connects the driving member of the clutch to the driven member thereof and simultaneously switches on the electrical current. After the clutch has made one complete revolution, which is suflicient to operate the machine through its complete cycle, the driving member of the clutch is automatically disengaged from the driven member and the electrical current is simultaneously switched off. A non-repeat mechanism has been provided for preventing unintentional successive operations of the machine, which are caused by retaining the starting bar in depressed position after the cycle of operation has been completed.

Calculating machines of this type are generally equipped with a traveling carriage which is supplied with an automatic return mechanism that allows the traveling carriage to be returned from any tabulated position to its starting position. In this instance the return of the traveling carriage may be accomplished automatically by means of stops located as desired on the traveling carriage, or by means of a hand lever conveniently located adjacent the keyboard.

Where the automatic traveling carriage return is employed it is necessary to have an operating mechanism for said carriage return independent of the regular machine operating mechanism.

- This is due to the fact that the machine operatposition where a prearranged stop thereon engages the return mechanism, or when the hand return lever is depressed, an escapement device under spring tension is released for one step of movement which closes the motor switch to set the motor in operation. When the traveling carriage is returned to its starting position, which position is also controlled by means of prearranged stops on the traveling carriage, the escapement device is again released for another step of movement to open the motor switch, which in turn stops the motor.

. A friction device operated by the motor keeps constant tension on the spring that operates the escapement device so that the switch controlling mechanism for the carriage return is ready to operate at all times.

In addition to-operating the escapement mechanlsm to control the motor switch the carriage return stop, or the carriage return lever, also clutches the carriage return gear to its driving member from which it is automatically declutched immediately after the carriage is returned to its starting position.

and is in fact undesired, as it tends to make the motor and the machine operate too fast. To remedy this condition a speed regulating device has been incorporated in this instant invention. The speed regulator keeps the motor operating at uniform speed regardless of load, and also regardless of any minor fluctuation in the supply current. This speed regulator is of the governor type and relies upon centrifugal force to interrupt the flow of current to the motor when the motor exceeds the desired speed.

The mechanism briefly described above, which is pertinent to the instant invention, will be thoroughly treated in the detailed description following:

DmAxLED DESCRIPTION Motor mechanism As the electric motor of the instant invention is of conventional design and as it has been used in former machines, it will be but briefly described in the succeeding description.

The motor is enclosed in a suitable housing or framework 30 (Fig. l) which is preferably bolted to a base plate 3! of a calculating machine, the case 32 of which is partially shown in dot and dash lines. Extending through openings in a keyboard plate 33 are stems 36 and 35 of a machine release or starting bar 35. The stem 34 is pivoted to a lever 37 loose on a stud 38 secured in the machine right side frame (not shown) and the lower end of the stem 35 is pivoted to one arm of a three-armed lever 39 loose on a stud 45. also secured in the right machine frame. An arm ii of the lever 39 is bifurcated to embrace a stud 52 in the lever 37 while another arm of said lever 39 carries a stud 43 which cooperates with an abrupt surface i l of a latch 55 loose on a stud 135 secured in the right machine frame.

The latch has pivoted thereto one end of a pitman 67 the other end of which is bifurcated to straddle a stud 38 secured in the right machine frame. The pitman ll carries a stud 59 embraced by a forked extension of a bell crank 50 loose on a stud 58 secured in the motor frame 39. (See also Figs. 4 and 5.) The bell crank 55 is connected by a stud 52 to a clutch release arm 53 rotatably supported by the stud 55. The rearward end of the arm 53 is shaped to cooperate with abrupt surfaces on a clutch stop cam 54 and a roller carrying plate 55. The stop cam 54 is secured to a hub 56 of a clutch cam 51 turnably mounted upon a stud 58 secured in the motor frame 30. The plate 55 is rotatably supported by the. hub 56 between the cams 54 and 57 and has fast therein studs which loosely support three rollers 59, which cooperate with the clutch cam 57 and the inner surface of a clutch driving drum 60. The clutch driving drum 50 is connected to a clutch driving gear 5! also rotatably supported by the stud 58. The teeth of the gear 5| mesh with the teeth'of a worm gear 52 secured on a. motor armature shaft 53 opposite 75 auasu Loose on the stud I (Figs. 2 and 5) is a clutch I return arm 54 carrying a roller 85 which cooted to a drive arm I8, secured to the main drive shaft H of the calculating machine.

From the foregoing description it will be seen that the clutch driven member is composed of the members 54, 51, 58 and 81 secured together in "fixed relation and the plate 55 (Fig. 4) which as previously stated is loosely supported by the hub 58. It will also be seen that the clutch driving member is composed of the drum 88 (Figs. 4 and 5) and the gear 5|.

' The rearward end of the clutch release arm 58 (Figs. 4 and 5) cooperates with an arm I2 of a yoke I8 loose on a stud I4 secured in the motor frame 88. Another arm I5 of the yoke I8 is adapted to coact with an arm I8 secured on a shaft I1 opposite ends of which are journaled in upturned ears I8 of a switch supporting bracket I8, secured to the frame 88.

Secured to the shaft I1 is an L-shaped arm 88 having secured thereto a switch operating block 8I composed of insulating material which cooperates with a pair of contact arms 82 of the motor switch 88. Secured on the shaft II (Fig. 4) is an arm 84, which cooperates with a hook 85 of a latch 88, pivotally supported by a stud secured in the bracket I8 and having a roller 81 which cooperates with a camming surface on the plate 8''.

Calling attention to Figs. 1, 2 and 4, depressing the starting bar 88 rocks the lever 81 counter clockwise, against the tension of a spring 88, and the lever 88 clockwise to disengage the stud 48 from the abrupt surface 44 of the latch 45. This allows the bell crank 58 and the clutch release arm 53 to be rocked counter clockwise by a spring 88 until a flat surface of said arm 53 engages the frame 88, and a projection 8| of the pitman 41 contacts a hub 82 of the latch 45. Counter clockwise movement of the arm 58 (Fig. 4) disengages its rearward end from the cam 54 and the plate 55, and simultaneously through the arm 12 rocks the yoke 18 clockwise which by means of the arm in cooperation with the arm I8 rocks the shaft I1 counter clockwise, as observed in Fig. 5, to move the switch contact arms 82 into engagement with other contact members of the switch 88 to close the electrical circuit to the motor, thereby causing said motor to operate.

When the plate 55 is released as just explained, spring-pushed shell-shaped plungers 83 carried by the cam 51 force the rollers 58 and the plate 55 counter clockwise, thereby wedging said rollersbetween the inner surface of the drum 58. and the camming surface of the cam 51. Immediately thereafter the motor circuit is closed, as explained above, causing said motor to rotate the gear 8i and the drum 88 in a counter clockwise direction, and as the driven member of the clutch,

has been coupled to the drum as explained jnon-released or home positions, after the camabove, it moves in unison therewith one complete counter clockwise revolution, further movement thereof being arrested by the arm 53 in a manner presently to be described.

As the plate 51, which it will be recalled is a part of the driven member of the clutch, starts its counter clockwise movement the camming surface 88 moves beyond the roller 81 allowing the latch 88 to be rocked clockwise by a spring 84 to move the hook 85 into the path of the arm 84 to latch the arm 88 and the switch contact arms 82 in effective positions. As the plate 81 continues its cycle of movement counter clockwise, the camming surface 88 engages a roller 85 mounted on an extension of the bell crank and rocks it and the arm 58 clockwise to home positions. This through the pitman 41 (Fig. 1) rocks the latch clockwise, thereby allowing the stud 43 under tension of the spring 88 to reengage the abrupt surface 44 of said latch 45 to retain the arm 58 (Fig. 4) in the path of the stop cam 54 and the plate 55 after the camming surface of the plate 81 has passed beyond the roller 85. As the clutch driven member nears the end of its cycle of move-' ment the arm 58 engages, first the plate 55 to disengage the rollers 58 from the inside surface of the drum 58 and then the camming surfaces of the cam 51 to declutch the driven member of the clutch from its driving member. Immediately thereafter the camming surface 88 engages the roller 81 to rock the latch 88 counter clockwise to move the hook 85 out of the path of the arm 84. This frees the shaft I1 and due to the fact that the switch contact arms 82 are composed of spring material they immediately free themselves from the other contact members of the switch 88 thereby interrupting the flow of electrical current to the motor.

The clutch driven member is assisted to and retained in home position by means of a strong spring 88 (Fig. 2) which is tensioned to urge the arm 84 in a clockwise direction, thereby causing the roller 85 in cooperation with the periphery of the cam 88 to give added impetus to the clutch driven member as it nears its home position. The configuration of the cam 85 is such that the stop cam 54 (Fig. 4) is maintained in engagement with the release arm 58 irrespective of the tendency of the spring plungers 83 to urge the clutch driven member in a clockwise direction.

Non-repeat mechanism Referring to Fig. 1, in case the operator's hand is inadvertently left upon the starting bar 8'8. a non-repeat mechanism functions to prevent repeat operations of the machine. This mechanism will now be described.

Loose on the stud 48 is a pawl 81 urged clockwise by a spring 88 into engagement with a stop stud 88 secured in the lever 38. Depressing the starting bar 38 rocks the lever 38 clockwise and due to the action of the spring 88 the non-repeat pawl 81 moves in unison therewith to move a hook I85 thereof in the path of a similar hook I88 on the latch 45.

If the starting bar 38 is held in depressed position as the machine nears the end of its cycle "ofm'ovement, obviously the hook I85 of the nonrepeat pawl 81 will be retained in the path of the hook N8 of the latch 45. Consequently when said-latch 45 is restored clockwise to effective position, as explained earlier herein, the hook I88 will engage the hook I85 of the non-repeat pawl 8] to retain the latch 45 and connected parts in ming surface 88 of the plate 8'! moves out of the path of the roller 85 in the bell crank 58 (see also Figs.'2' and 4). The instant that pressure is removed from the starting bar 88 the spring 88 through the lever 81 rocks the lever 88 counter clockwise to move the stud 48 into engagement l5 70 the spring H2.

with the abrupt surface 44 and simultaneously by means of the stud 99 disengages the hook I of the pawl 91 from the hook I06.

The clutch driven member in making its cycle 5 of movement by means of the plate 61 (Fig. 2) and the link 69 rocks the arm and the shaft 1I first counter clockwise and then clockwise back to home position, thus causing the mechanism of the machine to function.

10 Motor speed controlling mechanism To repeat in part a-statement previously made, due to the fact that the motor of the instant invention starts under full load, it is necessary that 1 said motor be constructed with a reserve of power in order that it willgain momentum quickly to operate the machine at the desired speed. However, once the motor has'gained momentum this reserve of power is unnecessary and would .39 cause the motor to run away from itself were it not for a speed controlling or regulating device which interrupts the flow of current to the motor when the desired speed is exceeded. This speed controlling device also keeps the motor operating at a constant speed regardless of supply current fluctuation. Such mechanism will now be described.

Directing attention to Figs. 2 and 3, secured on an extension of the armature shaft 63 is a pa disk I91 having therein a plurality of transverse grooves I99 arranged to receive ball bearings I09. The disk I01 has therein a recess adapted to loosely receive the tenon of a retaining cone III) I loosely mounted on the extension of the armature 3g shaft 63 and having therein an annular groove I II adapted to retain the ball bearings I09 in the grooves I09. The retaining cone III] is counterbored to receive an open-coiled compression spring M2 the tension of which may be varied by means of a bushing H3 mounted on the extension of the shaft 63 and having a tenon IIt which fits loosely in said counterbore in said retaining cone IIU. The periphery of the cone II@ is tapered to cooperate with a similarly 45 tapered surface of a shoe I I5 carried by a breaker arm IIS rotatably supported by a bracket III secured to a disk I I8 composed of di -electric material secured in a recess N9 of the motor frame 39. The breaker arm II 6 has a contact point 5@ I20 which, by means of a spring I22, is normally retained in engagement with a similar point on a bracket I2I secured on the disk I I8.

The wire from one of the switch contact arms 82 (Fig. 4) leading to the motor is connected to 55 the bracket I2I (Fig. 3) and this connection is continued by a wire connected to the bracket I I1 and leading to one of the motor field coil terminals. A cover plate I23 (Fig. 2) is secured over the recess N9 of the motor frame 30 to protect the speed control mechanism from dust and injury.

, As long as the motor operates at a normal speed the contact point I20 on the breaker arm I I6 remains in engagement with the contact point on 65 the bracket I2I. As the motor speed becomes excessive the centrifugal action of the ball bearings I99 in cooperation with the annular groove II I in the cone IIIl forces said cone III) to the left as observed in Fig. 2 against the tension of The tapered periphery of the cone III! in cooperation with the shoe II5 moves the breaker arm IIIi clockwise, as observed in Fig. 3, thereby separating the contact points to interrupt the flow of current to the motor. As

1"- soon as the motor speed becomes normal, the

cone IIIldrops back to its normal position thus allowing the contact points'to again become'engaged, thereby causing resumption of current flow to the motor.

From the foregoing explanation it will be seen 5 that the speed control device permits the use of an oversized motor to insure easy starting, by providing a means for controlling the speed of the motor after it has gained momentum.

TaAvELrNo CARRIAGE RETURN MECHANISM Carriage return gear operating mechanism Directing attention to Figs. 1 and 2, the carriage return operating mechanism receives its power from the motor by means of an extension I24 coupled to the armature shaft 63, said extension being connected by suitable gearing to an oblique shaft I25, which drives a vertical shaft I26 journaled in a bracket I21 secured to the case 32 that encloses the calculating mechanism. Secured on the shaft I26 Figs. 9 and 10, is a. clutchmember I28 having downwardly extending teeth adapted to cooperate with similar upwardly extending teeth on a carriage return gear I29 loosely supported by the shaft I26. The hub of the gear I29 has an annular groove I30 adapted to receive the rounded end of a shifting arm I3I pivotally mounted on the bracket I21. The arm I3I is connected by a spring I32 to a lever I33 pivotally supported by a stud I 34 (Fig. 9) secured in the case 32.

The right-hand end of the lever I 33 extends through an opening in a lever I35 rotatably supported by a stud I36 carried by a bracket I31 secured to the case 32. The forward end of the lever I35 is straddled by a slot in the lower end of a vertical pin I99 loose in a hole in the case 32. The upper end of the pin I39 is adapted to cooperate with an angular surface on an extension IQI] of a slide I lI shiftably supported in a 40 slot in the case 32. The slide MI has an upturned extension M12 adapted to be engaged by the lower end of a return pawl I63 loosely mounted on a carriage return stop I945 adjustably supported by a carriage stop bar I 35 secured to the travelmg carriage.

The carriage return gear I29 Figs. 1 and 10 constantly meshes with a carriage return rack I46 shiftably supported on the traveling carriage by means of slots I61 in right-angled extensions 50 M8 and H39 which embrace rollers I50 turnably supported by studs I5I secured in the traveling carriage frame. A yieldable element (not shown) is tensioned to urge the rack I46 toward the right and normally retains. it in the position shown in Fig. 10. An adjustable stop I52 supported by the stop bar I 45 has a downwardly extending projection I53 adapted to engage an upwardly disposed stop bar I54 supported by a cross frame of the machine.

As the traveling carriage approaches the terminus of its forward movement to the left the pawl I 53 (Figs. 9 and 10) of the stop I44 engages the upturned extension I92 of the slide IEI forcing 5 said slide toward the left causing the angular surface on the downward extension I40 to force the pin I39 downwardly. This through the levers I35 and I33 and the closely coiled spring I32 rocks the arm I3I to shift the carriage return gear I29 upwardly, causing the clutch teeth carried by said gear to move into engagement with the teeth of the member I29. Simultaneously the upward movement of a link I55 which connects the lever I35 to the carriage return switch operating mechanism, presently to be described, operates said switch to start the motor.

The motor revolves .the shafts I26 and I26 in the direction indicated by the arrow, causing the return gearl'26 in cooperation with the rack I46 to return the traveling carriage toward the right as observed in Fig. 9 and toward the left as observed in Fig. 10 until the downwardly extending projection I56 of the stop I52 engages the bar I54 to arrest the return movement of the traveling carriage. The rack I46 due to its yieldable connection to the traveling carriage moves on independently thereof guided by the rolls I56 in cooperation with the slots I41. The configuration of the slots I41 is such that the rack is forced downwardly as it nears the terminus of its independent movement, causing the lower edge of said rack to engage a flange I56 of the gear I26 to force said gear downwardly to disengage the "clutch teeth thereon from the teeth of the member I26; the yieldable member (not shown) then returns the rack I46 to the position shown in Fig. 10.

Downward movement of the gear I29 through switch, thereby stopping the flow of current to the motor.

The arm I3I (Fig. 10) is retained in either of its moved positions by means of a pawl I51 pivotally supported by the bracket I21 and having a nose 6 which is retained in engagement with a projection I56 of the arm I3I by a spring I66. The relation of the nose I58 and the projection I66 is such that the arm I3I is yieldably retained in either of its moved positions.

Carriage return switch operating mechanism The mechanism that operates the motor switch for carriage return operations operates independently of the machine releasing mechanism. Consequently the traveling carriage may be returned to starting position at any time without interfering in any way with the machine releasing mechanism. This mechanism is well shown in Figs. 5, 6, 7 and 8, and will now be described in detail.

Calling attention specifically to Figs. 6 and 7, the lower end of the link I55 is pivotally connected by a stud I6I to an arm of a yoke I62 rotatably supported by a stud I63 secured in the motor frame 36. Another armor the yoke I62 is shaped to form a hook I64 and a pawl I65 which in cooperation with the teeth of an escapement ratchet I 66 provides an escapement device for controlling a switch operating cam I61. Thematchet I66 and the cam I61 are secured in fixed relation to each other by means of the tenon of a hub I66 and the tenon of a ,pin I66, the latter extending through a concentric slot in a gear I16 loosely mounted on a stud I1I, secured in the frame 36 by means of a hub I12, the tenon of which is secured in the gear I16. The outside diameter of the hub I12 iits loosely in the bore of the hub I66 to form a bearing for the ratchet I 66 and the cam I61.

A torsion spring I16 'flts loosely over the outside diameter of the hub I66, one end of said spring being formed to embrace the pin I66 and the other end a stud I14 in the gear I16. The gear I' meshes with a pinion I15 loosely supported by a stud I16 secured in the motor frame 66 and has secured thereto a driving disk I11 ca 'y l studs I16 the bodies of which fit loosely in holes in a similar disk I66 loosely mounted upon a hub I6I of the pinion I15. The disks I11 and III are similarly undercut to form a bearing for a ring gear I62 which is pinched between friction disks I66 by means of compression springs I64 carried by the studs I16 tensioned to force the disks I11 and I66 together. The teeth of the ring gear I62 mesh with similar teeth in a pinion i 65 loose on the stud 56 and having tenons I66 which fit within recesses in the hub of the worm gear 6i, Fig. 5.

When the lever I35 (Fig. 9) is rocked counter clockwise by the carriage stop I44 to operatively couple the carriage return gear I26 to the driving member I26 as explained earlier herein the link I55 is moved upwardly. This through the stud I6I (Figs. 6 and 7) rocks the yoke I62 counterclockwise to disengage the pawl I65 from the ratchet I66 and moves the hook I64 in the path of the teeth of said ratchet I 66. This frees the ratchet I66 and the cam I61 to the action of the spring I13 which through the stud I69 rotates said ratchet and said cam counter clockwise one step of movement which is determined the arm I3I, spring I62, levers I33 and I35, returns the link I55 downwardly to open the motor by the hook I64 engaging the succeeding tooth of said ratchet I66. This counter clockwise movement of the cam I61 is suihcient to cause one of a series of high points I61 thereon in cooperation with a roller I 66 carried by an arm I66 of the yoke 16 to rock said yoke clockwise, which through the arm 16 (Figs. 4 and 5), the shaft 11 and the arm 66, moves the motor switch contact arms 62 to effective position to start the motor operating. This through the shafts 225 and I26 and the driving member I26 rotates the gear I26 to return the traveling carriage to starting position.

The disengaging of the carriage return gear I26 from the driving member I26 by the downward movement of the rack I46, as explained earlier herein, rocks the lever I35 (Fig. 9) clockwise to move the link I55 downwardly, which in turn rocks the yoke I62 (Figs. 6 and 7) clockwise causing the hook I64 to be disengaged from the ratchet I66 thereby allowing said ratchet under tension of the spring I13 to make another step of movement which is determined by the pawl I65 engaging the succeeding tooth on the ratchet I66. As the cam I61 is integral with the ratchet I66 it moves in unison therewith sufliciently to place a low point thereon opposite the roller I86. This allows the yoke 13 (see also Figs. 4 and 5) to be returned counterclockwise by the spring action of the contact arms 62 as the switch opens.

By observing Fig. 9 it will be seen that manual means are provided for rendering the carriage return means eiiective at any desired time. This means consists of a lever I96 pivoted on the stud I36 and having a conveniently located fingerpiece I6! adjacent the machine keyboard. Depressing the finger-piece I9I rocks the lever I96 and the lever I35 counterclockwise to lift the link I55, which as previously explained causes the traveling carriage to be returned to starting position.

Tension is reapplied to the spring I13 each time the motor operates, by the mechanism shown in Figs. 6, 7 and 8. The pinion I65 which operates whenever the motor operates, drives the ring gear I62 which through the clutch member composed of the disks I11 and I66, friction rings I66 and the pinion I15 rotates the gear I16 in a counterclockwise direction until stopped by the end of the concentric slot therein engaging the pin I69.

This rewinds the spring I13 thus placing it in 15 readiness for another carriage return operation. After the gear I10 has been stopped as explained above the ring gear I82 continues to revolve as long as the motor operates, slipping between the faces of the friction rings I83.

By observing Fig. 7 it will be seen that less movement is required of the cam I 61 to stop the motor than is required for starting the motor. This uses only about half of the tension of the spring H3 thus allowing the coasting action of the motor after the current has been shut oil, to fully rewind said spring H3 in preparation for another carriage return operation.

SUMMARY summarizing briefly it will be seen that the motor of the instant invention has two distinct means for operating its switch, neither of which interferes with the other in any way. In case there is an overlapping of either machine operation or carriage return operation both operations will be completed without any interference from the other. While it is hardly possible that a carriage return operation will be started before the machine operation is completed, still the mechanism of the instant invention is fully adapted to take care of such a condition.

In comparison, a start-stop motor as adapted for use on calculating machines, has several distinct advantages over a constantly running motor. As the start-stop motor runs only when the machine is operating or the traveling carriage is being returned, there is a decided saving in current over a constantly running motor from this feature alone. Naturally there is quite a saving in motor upkeep, as the start-stop motor operates only about half as much as a constantly operating motor. Also it is quite possible for a constantly running motor to be left running over long periods of time, ,for example, lunch period or at the close of business hours, with the resulting cost in current consumption and motor wear. Such an occurrence is impossible with a startstop motor.

While the forms of mechanisms herein shown and described are admirably adapted to fulfill the objects primarily stated, it is to be understood and means including an escapement mechanism,

a slippage element driven by the motor and operable to tension the escapement mechanism, and means operated by the escapement mechanism to control the operation of the switch mechanism.

2. The combination with an electric motor, of a switch mechanism for controlling its operation; means including an escapement pawl and a spring urged element controlled for step by step movement in a single direction by said escapement pawl, said means being operable to control said switch mechanism; and means operated by the motor for placing a tension on the spring urged element.

3. In a calculating machine with an electric motor drive, the combination of a switch for the motor; means including an escapement mechanism for controlling the operation of the switch; means for automatically tensioning the escapement mechanism for operation; and means to .operation of the switch.

5. In an electric motor with a make-and-break switch, the combination of an element associated with the switch; an escapement device associated with the element; a spring to actuate the escapement device; a friction member driven by the motor totension the spring; and means to release the escapement device step by step to operate the element to control the switch.

6. In an electric motor with a make-and-break switch; the combination of an element associated with the switch; a cam associated with the element; a ratchet integral with the cam; a spring to actuate the cam and ratchet; a friction member driven by the motor to tension the spring; means to allow intermittent escapement oi the ratchet to operate the cam which by means of the element controls the switch.

7. An electric motor, a switch device for the motor, an escapement arm, a member operable step by step under control of said escapement arm, means controlled by said member to close and open said switch upon alternate operations of said member, and means operated by said motor to urge said member in its step by step operation.

8. An electric motor; a switch device for the motor; cam means for controlling the alternate opening and closing of the switch; a ratchet connected to said cam means and operable step by step in a single direction; a shiftable pawl; and a spring to actuate the ratchet and cam means under control of said shiftable pawl, said pawl being shiftable to two positions and when in one position releasing the ratchet to make a step of movement whereby the cam means controls the closing of the switch device to start the motor, and when shifted to its other position releasing the ratchet to make another step of movement whereby the cam means controls the opening of the switch to stop the motor.

CHARLES H. ARNOLD.

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