No. 841,588, PATENTED JAN, 15, 1907. R. SHIPMAN, MEANS FOR PREVENTING SLIPPAGE OF TRACTION , APPLICATION FILED MAY 3, 1906, 2 SHEETS-SHEET 1.

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R N No. 841,588, PATENTED JAN. 15, 1907. R, SHIP MAN. MEANS FOR PREVENTING SLIPPAGE OF TRACTION WHEELS, APPLICATION FILED MAY 3, 1906.

28HEETS-SHEET 2, UNITED STATES PATENT OFFICE. NA RALPH 'SHIPMAN, OF SUNBURY, PENNSYLVANIA. MEANS FOR PREVENTING SLIPPAGE OF TRACTION-WHEELs. d No. 841,588. Specification of Letters Patent. Patented Jan. 5, 1907. Application filed May 3, 1906. Serial No, 815,0ll, To all whom it may concern: , only one of said branch pipes Beit known that IRALPH SHIPMAN, a citi being shown in the drawings. By turning zen of the United States, residing at Sun the crank 4 in one direction or the other the bury, in the county of Northumberland and valve 2 may be turned so as to throttle the State of Pennsylvania, have invented certain steam passing to both steam-chests or to per new and useful Improvements in Means for mit the steam to pass through freely. This Preventing Slippage of Traction-Wheels, of valve 2 is operated automatically, so as to which the following is a specification throttle the steam flowing to the steam My invention relates to means for auto chests and cylinders whenever the slippage of O matically regulating the power applied to the the driving-wheels exceeds a predetermined traction-wheels of or other mo amount--that is, in practice the traction tor-driven vehicles, so as to prevent slippage wheels of a locomotive hauling a train of cars of the traction-wheels. . . . will have some slight and practically constant By means of my invention the motor may slippage, which may amount to, say, one apply full power to the traction-wheels up to revolution in twenty, fifty, or a hundred, the point where slippage of the wheels would and it is not desirable to reduce the power occur; but any sudden slippage of the wheels applied to the driving-wheels on account of or a slippage in excess of a predetermined this slight constant slippage which qccurs annount E. result in diminishing the power through various causes while the train is in 75 of the motor to such an extent that further operation under ordinary conditions. In slippage cannot take place. my invention, therefore, the throttle-valve is In carrying out my invention I provide a not operated to reduce the flow of steam for controlling device for throttling or otherwise this slight constant slippage, but any slippage varying the power of the motor and means which occurs in excess of the slight constant 25 operated by one of the traction-wheels and a slippage referred to will cause the throttle truck or trailer for actuating this con valve to immediately throttle the steam to a trolling device to reduce the power of the sufficient extent to stop the wheels from slip motor when slippage occurs and to gradually 9. isease the power when the wheels cease to p fe automatic controlling of the throttle Slp . . . valve 2 is accomplished by the following In the accompanying drawings, which mechanism: On the 7 of one of the pony illustrate my invention, fg. 1 is a side ele truck-wheels 8 is secured a sprocket-wheel 9, vation of a locomotive having my improve which is connected by a sprocket-chain 10 to ments applied thereto. Fig. 2 is a plan view 8, sprocket-wheel 11, the latter being secured 90 35 of the governing mechanism for automatic to a counter-shaft 12, arranged parallel with ally throttling the steamwhen slippage of the the axle 7 beneath the boiler of the engine in driving or traction wheels occurs. Fig. 3 is a suitable hangers 13, only one of which is . section on the line 33 of Fig. 2. Fig. 4 is a shown in Fig.1. As practically no slippage section on the line 4 4 of Fig. 3. Fig. 5 is a occurs between the pony truck-wheel and the 95 40 side view of a portion of an electric-motor car track T, if the circumferential length of the having my improvements applied to a truck, wheel-tread is, for instance, one hundred and Fig. 6 is a plan view of the governing de inches, the pony truck-wheel will turn oncefor vice illustrated in Fig. 5. each one hundred inches of track traversed Referring to Figs. 1-4, inclusive, of the by the locomotive, and the number of revolu Od 45 drawings, A indicates in outline sufficient of tions of the counter-shaft will be directly in . a steam-locomotive for the purpose of illus proportion to the length of track traversed trating my invention. In the pipel, leading and its speed will be in direct proportion to from the steam-done of the boiler, is ar the speed of the truck-wheel. A sleeve 14 is ranged a controlling-valve 2, which is rotata loosely mounted upon the shaft 12, and this 50 bleby means of a rod or stem 3, extending sleeve has a sprocket-wheel 15 secured there vertically downward through the smoke-box to and connected to a sprocket-wheel 16 on of the locomotive and having secured to its one of the driving- 17 of the locomotive lower end a crank or lever 4. The valve 2 is by a sprocket-chain 18. The counter-shaft shown in the rear branch of the fitting 5, 12 and sleeve 14 turn in the same direction; C 55 which connects the pipe 1 with the branch but the sprocket-wheels are so proportioned pipes 6, leading to the steam-chests of the that the shaft 12 rotates at a slightly-greater 86,588 speed than the sleeve when the locomotive is the latter being connected to the engineer's operating without slippage of the drivers-as, reversing-lever 43 in the engine-. . . . for instance, where R locomotive is drifting In Fig. 1 the engineer's lever is thrown with steam cut off. slightly forward of the center, and in this po The shaft 12 has a cam-hub 19 journaled sition the sleeve 38 is drawn away from the thereon, and this hub has at one end a V curved surface 29 of the shank of the pawl, shaped notch or recess 20. A cam-collar 21, permitting the tooth 34 of the pawl to en splined upon the sleeve 14, so as to rotate gage the ratehet-teeth. 36, as shown in Fig. 4. therewith and be movable longitudinally When the reversing-lever is in the central O thereon, has a wedge-shaped end 22, which position, the sleeve 38 is moved part way 75 fits within the notch or recess in the hub 19. onto the curved surface of the pawl and The wedge-shaped end of the collar21 is nor presses the head of the pawl into a central mally held within the W-shaped recess in the position, where neither of the teeth 34 or 35 hub by a spring 23, interposed between the will engage the ratchet-teeth. When the sprocket-wheel15 and the collar. The in reversing-lever is thrown back of the center, clined faces of the hub and collar form cam the spring-tooth 35 on the pawl comes into surfaces by means of which any rotation of engagement with the ratchet-teeth. In the hub and collar relatively to one another other words, when the engine is moving for will cause the collar to move longitudinally ward the pawl-tooth 34 engages the ratchet upon the sleeve 14 against pressure of the teeth atoneside of the shaft2. When the en spring 23. Normally the shaft 12 turns gine is moved backward, the tooth 35 of the faster than the sleeve 14; but a slippage of pawl engages the ratchet-teeth at the oppo the traction-wheel will cause.the sleeve 14 to site side of the shaft, and when the engine is move faster than the shaft 12. Means are stopped neither of the pawl-teeth engages the 25 provided for preventing the hub 19 from ratchet-teeth. The pawl-tooth 35, as shown moving faster than the shaft 12, and there in Fig. 4, is movable longitudinally within fore when the sleeve is turned faster than the head of the paw and normally pressed said shaft the hub being held down to the outward by a spring 44. The paw-tooth 34 speed of the shaft will cause the collar 21, is arranged to slide over or past the teeth 36 30 which turns with the sleeve, to move longitu when the shaft 12 is moving faster than the 95 dinally on the sleeve away from the hub. hub t9 in the direction indicated by the ar This longitudinal movement of the collar 21 row in Fig. 4, but to engage the ratehetteeth causes a lever 24 to rock about its pivotal 36 when the hub 19 tends to move faster point 25. This lever has an elongated eye or than the shaft in the same direction. Simi 35 slot 26 at its free end, which engages a pin 27 larly when the engine is reversed the spring OO upon the crank 4. It will be seen that any tooth 35 will slip over the teeth 36 when the movement given to the lever 24 will cause a shaft is moving faster than the hub and both movement of the throttle-valve 2, which is are moving in a direction opposite to that in connected to the lever by the rod 2 and crank dicated by the arrow in Fig. 4; but if the hub 4. As shown in the drawi ngs, the collar 21 begins to move faster than the shaft and in the IoS has a groove 28, which is engaged by a yoke same direction the spring-tooth 35 will lock 24 on the lever. with the ratchet-teeth and prevent the hub In order to permit the shaft 12 to turn from moving faster than the shaft. freely within the sleeve 14 and hub 19 at a In operation when the reversing-lever is 45 faster speed than said sleeve and hub and yet thrown forward the collar 38 is moved out of o prevent the hub from being driven at a faster engagement with the shank of the pawl and speed than the shaft when slippage of the the tooth 34 on the pawl is yieldingly pressed drivers occurs, and also to arrange the parts into engagement with the ratchetteeth.36 by so that they will operate the same when the the spring 37. The shaft 12 will, as before locomotive is moving forward or backward, I stated, rotate in the direction indicated by Il 5 provide a pawl P, which has a shank 29 piv the arrow in Fig. 4 at a speed which is pro oted to the shaft 12 by a pivot-pin 30 and a portional to the speed of the truck or trailer head 31, which is... arranged within a trans wheel 8, by which it is driven, and the hun verse slot 32 in the shaft 12. The shank 29 ber of revolutions of the shaft 12 will be in extends longitudinally of the shaft within a direct proportion to the length of track tray. groove 33, and its outer edge 29" is curved, as ersed. The sleeve 14 and the hub 19 will shown. The head of the pawl has two teeth also rotate in the direction indicated by the 34 and 35, adapted to engage ratchet-teeth. arrow in Fig. 4, but at a slightly lower speed . 36 within the end of the hub 19. A spring than that of the shaft, if no slippage occurs. . . 37, arranged within a socket in the shaft 12, If a slight constant slippage oceurs, such as it I 25 normally presses the shank of the pawl out is desired to permit without throttling the ward. A sleeve 38 is arranged upon the engine, as may occur when an engine is under shaft 12 and movable longitudinally thereon way under normal conditions, the hub 19 by means of a befl-crank lever 39, a link 40, and shaft 12 may turn at practically the 65 and a lever and rod 41 and 42, respectively, same speed without affecting the operation; 841,588 8 but if a slippage of the driving-wheel Boc some skill on the part of the engineer to regul curs in excess of this predetermined amount late the flow of steam so that the engine will the sleeve 14 will be driven faster than the pull up to its full capacity without slippage shaft 12. The tooth or dog 34 of the pawl and that after a wheel has started to slip its will then hold the hub 19 and prevent it from tractive effort decreases and the wheels will 7o rotating faster than the shaft 12, thus caus-, generally make quite a number of revolu ing a relative movement between the hub tions before again catching the rail. This is and the sleeve 14. It will be evident that not only injurious to the locomotive and to this relative movement will cause the collar the fire in the furnace, which is torn up by the IO 21 on the sleeve to move longitudinally upon excessive exhaust, but the tractive effort is 75 the sleeve by reason of the cam-surfaces be less when the wheels are slipping than when tween said collar and the hub. This move they are engaging the rail with fill power at ment of the collar 21 will rock the lever 24, iust below the point of slippage. By means which in turn will operate the crank 4 and of my invention the throttle will be controlled rod 3, thereby turning the controlling-valve so that the engine may be worked at its full 2, so as to throttle the steam. The parts are power up to the point of slippage; but any so arranged that a sudden slippage of the sudden slippage in starting, or in operating driving-wheel of, say, one-eighth of a revolu the engine or any slippage during-operation tion will cause the throttle-valve to close to in excess of the amount which is predeter 2 o a sufficient extent to prevent further imme mined by the gearing will immediately throt diate SES or a constant slippage in ex tle the steam.to such an extent as to prevent cess oft at which occurs under ordinary cont further slippage. - ditions will result in the gradual throttling of In Figs. 5 and 6 I have illustrated my in the steam until slippage is prevented. The vention in connection with an electrically 25 amount of slippage which may occur without propelled vehicle. Where it is convenient to operating the throttle-valve is of course de belt or gear directly from the trailer-wheel termined by the dimensions of the sprocket axle to the traction-wheel axle, the counter wheels. If the shaft, 12 is geared so as to run shaft may be dispensed with, as shown in Eity. at the same speed as the Figs. 5 and 6. In Fig. 5, Cindicates a cars S eeve 14, of course the throttle-valve will be body and D indicates a four-wheeled truck. 95 operated with very slight slippage; but by An electric motor Mis suitably geared to the increasing the speed of the shaft 12 with re axle 50 of the traction-wheels 51. A E. to the sleeve 14 a greater amount of sprocket-wheel 16 upon the traction-wheel slippage may occur without affecting the axle is connected by a sprocket-chain 18 to . 35 throttle-valve. . This is a matter which of a sprocket-wheel 15, which is secured to a loo course will be adjusted to suit the conditions sleeve 14, journaled upon the axle 52 of the to be met. When the reversing-lever is trailing wheel 53. The sprocket-wheels are moved backward to reverse the engine, the proportioned so that the sleeve 14 will turn sleeve 38 on the shaft. 12 moves along the upon the axle 52 at a slightly lower speed shank of the pawl and presses the spring than the said axle and in the same direction. I o5 tooth 35 into engagement with the ratchet As in Figs. 1-4, inclusive, a collar. 21 is teeth in the hub, the tooth 34 being then out splined upon the sleeve and a hub 19 is jour of engagement. As the engine will then naled upon the shaft and a spring 23 nor move backward, the hub and shaft 12 will mally presses the taperingend 22 of the collar 45 both move in the opposite direction to that into the notch 20 of the hub. Apawl P op to indicated by the arrow in Fig. 4, and it will erates the same as in the previously-de: be seen that as long as no slippage occurs scribed figures, and a collar 38° is splined above the predetermined amount the tooth upon the axle 52 and movable to connect 35 will slip over the teeth.36 or remain sta either tooth of the pawl with the ratchet tionary with respect thereto; but if slippage within the hub 19, as in said previously-de II5 above said amount occurs the hub 19 will be scribed figures. The lever 26, operated by pressed by the sleeve i4 against the tooth 35 the collar 21, engages the controlling-arm2 and the collar 21 and hub will be moved rela of a rheostat R or other motor-controlling tively to one another, the former. being device for regulating the power of the motor 55 forced outward by the coöperating cam-sur in any well-known manner, not necessary to 2 o faces, as before, thus operating the lever 24 illustrate. The sleeve .38 may be shifted and through said lever the throttle-valve. when the motor is reversed by mechanically It will be understood, of course, that the connecting it with the motorman's reversing throttle-valve 2 operates entirely independ switch; but in the drawings I have shown a ently of the engineer's throttle-valve, and cam projection 53 upon the sleeve and a 125 guide-rod 54 upon the truck-frame, which ginethe latter is in operation.may be left wide open while the en engages the cam and moves the sleeve 38 . In startin a load it is well known by those longitudinally upon the axle when the motor skilled in t art that when the driving is reversed. In Fig. 6 the sleeve 388 is 65 wheels start to slip or lose the rail it requires shown moved as far as it will go toward the 4. 841,588 hub. 19. If the axle 52 is turning in the di by both of said wheels for actuating said de rection of the arrow, the rod 54, which is piv vice to decrease the power supplied to the oted at 55 to the truck-frame, may swing motor when the traction-wheel slips. past the end 53 of the cam as the latter 2. In a motor-driven vehicle, means for passes the rod, and a centering-spring 56 al preventing slippage of the traction-wheels ways returns the rod to the position shown in comprising a controlling device for regulat the drawing. If now the motor is reversed, ing the power of the motor, and a governor it will be seen that the end of the rod will en for actuating said device, said governor com gage the side of the cam which is adjacent Pig two members decidently driven O the hub 19, and as the rod only has a limited y a traction and a trailer wheel respectively, 75 movement between a pair of stop-pins 57 and means operated by changes in the rela tive speeds of said members for actuating fromthe sleeve the hub will 19 be and drawn off ofin thea direction pawl P. awayThus said controlling device. the position of the sleeve and of the pawl 3. In a motor-driven vehicle, means for . will be shifted at each change in the direction preventing slippage of the traction-wheels of movement of the car. comprising a controlling device for regulat The operation is substantially the same as ing the power of the motor, and a governor in the previously-described figures. In Figs. for actuating said device, said governor com 5 and 6 the lever 26 operates the arm2 of an prising two members independently driven electric controller, while in Figs. 1-4, inclu at different speeds by a traction and a trailer sive, the throttle-valve of a steam-engine is wheel respectively, and means operated by operated by the governor. When the speed changes in the relative speeds of said mem of the sleeve 14 increases above that of the bers for actuating said controlling device. trailer-axle 52, the pawl holds the hub 19, 4. In a motor-driven vehicle, a motor, a 25 and the collar 21 is moved in the direction to motor-controlling device, a trailing or truck cause the controller-arm 2 to insert resist wheel, a traction-wheel, and a governor for ance in the armature-circuit of the motor or said controlling device comprising a member otherwise reduce the power applied to the driven by the trailer-wheel, a member inde motor and slippage of the traction-wheels pendently driven by the traction wheel, cease. As the car then moves forward on means for engaging said members when the 95 the track without slippage the axle of the relative speeds of said members are mate trailer-wheels, rotating faster than the sleeve rially changed by slippage of the traction 14, permits the hub 19 to regain its position wheel, and means connected with one of said with respect to the collar, and the spring 23 members for actuating said controlling de 35 forces the collar 21 back to its original posi WCe. IOC tion, thus moving the controller-arm to in 5. In a motor-driven vehicle, a motor-con crease the power of the motor. After this, so trolling device, a traction-wheel, a trailing long as no slippage occurs, the hub 19 will be wheel, two rotatable members independ driven by the collar 22, but at a slower speed ently driven by the traction and trailing 40 than the axle 52. Whenever slippage in wheels respectively, the member driven by I o5 creases to an amount determined by the di the trailing wheel being arranged to nor ameter of the sprocket-wheels, the operations mally rotate faster than the member driven will be repeated. by the traction-wheel, said members com Any wheel that travels upon the track prising means operating by changes in the without slippage may be used instead of a relative speeds of said members for actuating O truck-wheel to drive one member of the said controlling device. governing device. If desired, the sleeve 6. hn a motor-driven vehicle, a motor-con which carries the sliding collar may be driven trolling device, a traction-wheel, a trailing from the trailer, and the other member of the wheel, two rotatable members independ 50 governor carrying the pawl may be driven ently driven by the traction and trailing I 15 om the traction-wheel, the teeth on the wheels respectively, the member driven by pawl for this change of course being re the trailing wheel being arranged to nor versed. In such case the gears will be pro mally rotate faster than the member driven portioned, of course, so that the member by the traction-wheel, one of said members 55 which is driven by the traction-wheel will comprising a positively-driven part and a 2 O turn when there is no slippage faster than the yieldingly-driven part axially movable with member which is driven by the trailer. respect to one another and having coöperat I do not intend to limit my invention to ing cam-surfaces, said yieldingly-driven part the exact arrangement shown in the draw having means for interlocking with the other 6o ings, as it is obvious that many changes may of said members when the speed of the slower be made within the scope of my invention. moving member is accelerated by slippage, What I claim is- . and connections between said positively 1. In a motor-driven vehicle, a motor, a driven part and said motor-controlling de motor-controlling device, a trailing or truck vice for operating the latter. 65 wheel, a traction-wheel, and means operated 7. In a motor-driven vehicle, a motor-con 84,588 trolling device, a traction-wheel, 3. trailing and means, actuated by the relativemove wheel, two rotatable members independ ments of said cam and yieldingly driven ently driven by the traction and trailing member for actuating said motor-controlling : wheels respectively, the member driven by device. 5 the trailing wheeh being arranged to nor 11. In a motor-driven vehicle, a motor mally rotate faster than the member driven controlling device, a trailing wheel, a trac by the traction-wheel, one of Said members tion-wheel, a clutch element positively comprising two parts, axially and rotatably driven by the trailer-wheel, two coöperating movable with respect to one another and cam devices driven by the traction-wheel at o having coöperating cam-surfaces, one of said a lower rate of speed than said clutch ele 75 E. being positively driven and the other ment, one of said clutch devices being posi eing yieldingly driven, said latter part hav tively driven and the other yieldingly driven ing means for interlocking with the other the latter having means for engaging said member when the speed of the slower moving clutch element when the speed of the devices member is accelerated by slippage, and one driven by the traction-wheel tends to exceed of said parts being operatively connected to the speed of the element driven by the trail the motor-controlling device. ing wheel and connections between one of 8. In a motor-driven vehicle, a motor-con said cam devices and the motor-controlling trolling device, a traction-wheel, a trailing device for actuating the latter. wheel, and means for actuating said device 12. In a motor-driven vehicle, a motor to decrease the power of the motor when the controlling device, a trailing wheel, a trac traction-wheel slips, comprising two coöper tion-wheel, a clutch element positively driven ative clutch elements, one rotatable by the by one of said wheels, two coöperating can trailing wheel, and the other rotatable, at a devices driven by the otherwheel, one of said lower speed, by the traction-wheel, one of cam devices being positively driven and the 90 said elements being yieldingly driven and the other yieldingly driven the latter having other positively driven, said elements being means for engaging the clutch element on the arranged to interlock when the slower-mov shaft when the relative speeds of the trailing ing element tends, by reason of slippage of and traction wheels are materially changed the traction-wheel, to exceed the speed of the by slippage of the latter wheel, and connect 95 faster-moving element, and means coacting tions between one of said cam devices and with said yieldingly-driven element for actu the motor-controlling device for operating ating the motor-controlling device. w the latter. 9. In a motor-driven vehicle, a motor-con 13. In a motor-driven vehicle, a motor 35 trolling device, a traction-wheel, a trailing controlling device, a trailing wheel, a trac oc wheel, and means for actuating said device tion-wheel, a clutch element positively to decrease the power of the motor when the driven by one of said wheels, two coöperating traction-wheels slip comprising two coöper cam devices driven by the other wheel at a ative clutch elements, one rotatable by the different speed from that of the clutch ele. 40 trailing wheel, and the other rotatable, at a ment, but in the same direction, one of Said Ios lower speed, by the traction-wheel, one of cam devices being positively driven and the said elements being yieldingly driven and the other yieldingly driven the latter having other positively driven, said elements being means for engaging the clutch element on the arranged to interlock when the slower-mov shaft when the relative speeds of the trailing 45 ing element tends, by reason of slippage of and traction wheels are materially changed o the traction-wheel, to exceed the speed of the by slippage of the latter wheel, and connect faster-moving element, and a cam coacting tions E. one of said cam devices and with said yieldingly-driven element for actu the motor-controlling device for operating ating the motor-controlling device. the latter. 10. In a motor-vehicle, a motor-control 14. In a motor-driven vehicle, a motor IIS ling device, a traction-wheel, a trailing wheel controlling device, a trailing wheel, a traC and means for actuating said device to de tion-wheel, a shaft positively driven by One crease the power of the motor when the trac of said wheels, a clutch element on said tion-wheels slip comprising a clutch element shaft, a sleeve journaled on said shaft, and 55 positively driven by one of said wheels, a positively driven by the other wheel, two - cam coöperating cam devices drive? by the sleeve, clutchEY element yieldinglydriven by driventhe other by saidwheel, cam a one being positively driven and the other and having a cam-surface coöperating there yieldingly driven, the latter having means with, the parts driven by the trailing wheel for engaging the clutch element on the shaft being arranged to normally turn faster than when the relative speeds of the shaft and I25 the parts driven by the traction-wheel, said sleeve are materially changed by the slippage clutch elements being arranged to interlock of the traction-wheel, and connections be- . when the slower-moving element, by reason tween one of said cam devices and the motor of slippage of the traction-wheel, tends to controlling device for operating the latter. 65 run faster than the faster-driven element, 15. In a motor-driven vehicle, a motor-. 30 6 84,588 control l device, a trailing wheel, a trac- faster-moving part, when the traction-wheel tion-wheel, two coacting cam devices driven slips, a reversing-lever for the motor, and by one of said wheels, one of said devices be means operated by the reversing-lever for ing positively driven and the other yieldingly reversing the ratchet mechanism...... 5o driven, connections between one of said can 18. In a locomotive, a throttle-valve, a devices and the motor-controlling device, a traction-wheel, a trailing or truck wheel and member driven positively by the other of said a governing device actuated by both of said wheels in the same direction as said cam de wheels for moving said throttle-valve. vices but at a different speed, said member 19. In a motor-driven vehicle, a motor 55 O and said yieldingly-driven cam having coact- controlling device, a trailing wheel, a trac ing paw?-and-ratchet mechanism constitut-tion-wheel, two coacting cam devices driven ing a clutch, arranged to prevent the slower- by one of said wheels, one cam device having moving part from exceeding the speed of the a V-shaped notch and the other having a ta faster-moving part, when the traction-wheel pering end fitting in said notch, a spring nor slips. mally pressing said, cam devices toward one 16. In a motor-driven vehicle, a motor- another, one of said cam devices being posi controlling device a trailing wheel, a trac-tively driven, and the other yieldingly tion-wheel, two coacting cam devices driven driven, connections between one of said cam by one of said wheels, one of said devices be- devices and the motor-controlling device, 65 20 ing positively driven and the other yieldingly. and a clutch member, positively driven by driven, connections between one of said cam the other of said wheels and adapted to en devices and the motor-controlling device, a gage said yieldingly-driven cam, when the member driven positively by the other of said relative speeds of the traction and trailing wheels in the same direction as said cam de-wheels change materially. vices but at a different speed, said member 20. In a motor-driven vehicle, a motor and said yieldingly-driven cam having coact- controlling device, a traction-wheel and a ing pawl-and-ratchet mechanism constitut-trailing wheel, a shaft positively driven by ing a clutch arranged to prevent the slower- one wheel, a sleeve journaled on the shaft and moving part from exceeding the speed of the positively driven by the other wheel, a cam 75 30 faster part, when the traction-wheel slips, splined on the sleeve, so as to rotate with and and means for reversing said ratchet mech- be movable longitudinally on the sleeve, a anism when the motor is reversed. cam journaled on the shaft and engaging the 17. In a motor-driven vehicle, a motor- cam on the sleeve, a spring normally pressing. controlling device, a trailing wheel, a trac- said cams together, connections between the 35 tion-wheel, two coacting cam devices driven cam on the sleeve and the motor-controlling by one of said wheels, one of said devices be- device for operating the latter, and a reversi ing positively driven and the other yieldingly ble pawl-and-ratchet mechanism between driven, connections between one of said cam the shaft and the cam which is journaled on devices and the motor-controlling device, a the shaft. 85 o member driven positively by the other of . In testimony whereof I affix my signature said wheels in the same direction as said cam in presence of two witnesses. devices but at a different speed, said member and said yieldingly-driven cam having coact RALPH SHIPMAN. - ing pawl-and-ratchet mechanism, constitut- Witnesses: 45 ing a clutch arranged to prevent the slower- Rob ERT WATsoN, moving part from exceeding the speed of the FRANCIs S. MAGUIRE.