US2940340A - Differential driving mechanism - Google Patents

Description

June 14, 1960 G. M. coANET 2,940,340

DIFFERENTIAL DRIVING MECHANISM Filed July 17, 1957 4 Sheets-Sheet 1 Fig. .7

.2' xm l l* HY June 14, 1960 G. M. COANET 2,940,340

DIFFERENTIAL DRIVING MECHANISM Filed July `1'7, 1957 4 Sheets-Sheet 2 June 14, 1960 G. M. coANET DIFFERENTIAL DRIVING MECHANISM Filed July 17, 1957 4 -Sheets-Sheet 3 n 0 l 2, A 6 f Fig. 72

Fig. 73

lill/III June 14, 1960 G. M. coANE'r 2,940,340

DIFFERENTIAL DRIVING MECHANISM Filed July 1'?, 195'? 4 Sheets-Sheet 4 United States Patent IOmce 2,940,340 Patented June 14, 1960 2,940,340 DIFFERENTIAL DRP/'ENG MECHANISM Guy Michel Coanet, Paris, France, assignor to Compagnie des Machines Bull (Societe Anonyme), Paris, France Filed July 17, 1957, Ser. No.l 672,394

Claims priority, application France July 17, 1956 4 Claims. (Cl. 74i-757) In computing machines and accounting or statistical machines controlled by record cards or tapes, it is sometimes necessary for ensuring correct operation of certain parts of the machine to adjust differently the instant of operation of some parts, depending upon the required speed of operation of the machine. These diierences in adjustment have the object of compensating for the effects of inertia developed during the starting or stopping of the controlled parts. It is sometimes also necessary to make some readjustments for compensating for the variations in the mechanical strength of parts which have become harder or freer after someperiod of operation. Particularly great diculties arisein correctly adjusting mechanisms having a variable load, .such as accumulators of accounting'machines in which carry-over mechanisms may be actuated at different instants during the operation of the accumulators. The influence ofthe variable loads of the inertia effects and of the variations in the passive resistances may be reduced by introducing into the mechanisms permanent. resistances (friction means or pawls for braking) butv these resistances increase the load on the transmissions, the noise and the wear on the mechanisms. These disadvantages are obviated by providing driving devices in the single-turn clutches of the type currently employed inY accounting machines. These devices ensure accurate starting and stopping of the mechanism in a clearly determined angular position independently of the load of the mechanism and of the speed of operation of the machine. For example, French Patent No. 527,463. applied for on July 2, 1920, is known, which relatesto a computing machine in which the wheels of theV accumulators are driven by diiferential mechanisms each comprising two bevel gears, one of which is coupled with a totalling wheel, and in which the starting and stopping of each totalling wheel is controlled by the actuation of an escapement mechanism which locks one of the bevel gears. In such a device, the escapement mechanism passes by an intermediate position in which the pawls of the escapement are in engagement with the two bevel gears of the differential simultaneously, which may cause deterioration of the mechanism. Moreover, in this mechanism the escapement must be maintained in its active position throughout the duration of the driving of a wheel of the accumulator.

The present invention has as its objectV to obviate these disadvantages and to provide a device which can be used for driving a mechanism and the stopping thereof in predetermined angular positions, while the driven mechanisrn can oppose within certain limits variable loads in the course of the operation and can be used at different speeds of the driving shaft of the machine.

One object of the invention is to provide a differential driving mechanism comprising a driving shaft, one or more planet wheels mechanically coupled with the said driving shaft, two bevel gears freely mounted on the planet wheel or wheels, so that one bevel gear, mechanically coupled with the mechanism to be driven, is driven by the rotation of the said shaft when the other bevel gear is locked, locking teeth on each bevel gear wheel, a control member arranged to occupy two active positions for the locking ofv one or other of the said bevel gears, the said member comprising opposite each of the said sets of locking teeth a locking pawl, the arrangement being such that when one pawl locks one bevel gear the other pawl releases the other bevel gear, and the said mechanism beingrcharacterised by the fact that there is providedan intermediate position of the control member, in which theV two pawls are simultaneously disengaged from the said teeth, land in that there is provided an aux,-

locking device consisting oftwo locking members each cooperating with the locking 'teeth of one bevel gear. The said locking members are rigidly. connected together and sordisplaceable that, when a locking member is maintained out of engagement with the locking teethV of one bevel gear as a result of the rotation of the latter, the other locking member is maintained in engagement with the locking teeth of the other bevel gear and maintain -it in the locked position.

Y The starting or stopping of a mechanism with a device designed in accordance with the inventionmay be controlled by impulses and affords great iiexibility and safety of operation, obviating any danger of deterioration of the mechanism.

Various embodiments of the invention and features thereof willvbel shown yby way of example in the course of the following description.V `and with reference to the accompanying drawings, in which:

Figure l is= a diagrammatic View of a driving device designed in accordance with the invention, partly in section along theline l-l of Figure 2,

Figure 2 is arsection along the line 2 2 of Figure l,

Figure 3 is a view of thecontrol member actuated by an electromagnet,

lFigure 4 is a view of the control member actuated, by an electromagnet different from that of Figure,

Figures 5 tol() are diagrammatic views of the auxiliary locking device in diiierentY positions,

Figure ll is a diagrammatic view of a modified em: bodiment,

Figure 12 is a transversesection through an accumuf latorv along the line 12,--12 of Figure14,

Figure 1.3 is a, side view of the accumulatorV of Fig: ure l2,

Figure 14 is a fragmentary plan view of the aceumuf lator according to Figure l2 as seen in the direction of the arrows 14-14 with some of the partsremoved, and

Figure 15 is an electric circuit diagram for the simplified control of a totalling wheel in addition or subtraction.

The differential driving-mechanism illustrated in Fig.- ures 1 and 2 is mounted on a driving shaft l. The planet wheels 2 and 3 of the differential can turn on a pin 4 which extends through the driving shaft 1 and the ends of which are engaged in a supporting ring 5' which supports other planet wheels.A 3av and 3b. The planet wheels of the differential engage with the toothedV rims 6 and 7 of the bevel gears 8 and 9 of the differential. The bevel gear 8 is provided with driving teeth l0 engaging with the pinion` 11 of a mechanism to be driven. The said teeth are arranged to engage with a number of other mechanisms to be driven at the same time. The bevel gear 3 is provided with locking teeth 12 and the Vbevel gear 9 is provided with locking teeth 13. A con;

trol member 14. rockably mounted on a supportingshaft 15 is provided with a locking pawl :i6 which is adapted to be brought into engagement with the locaing teeth 12 of the bevel gear 8, and. with a loing pawl 17 which is the inoperative position.

is adapted to b'e brought into enagagement with the lock- Y gaged from their corresponding looking teeth.` A'starting 'electromagnet 18 attracts,when energised, Va plunger arm 19, which is Yprovided with a bar 23 engaged inla fork 24 provided in the control member 14, which rocks to the left andengages the locking pawl 17 in the vteeth 13 of the passive bevel gear 9. A stop electromagnet k20 attracts, when energised, a plunger arm 19 which rocks'ithe Ycontrol member 14 to the right and engages the locking-pawl 16 in the locking teeth 12 Vofthe active bevel gearl8. Two springs 21 and 22 mounted o'n bevel gear 9.' If, for example, the driven mechanism is locked or brakes the active bevel gear 8 to the point of reducing its speed (which was twice that of the driving shaft), the reaction of theY planet wheels on the bevel gear 9 ,forces the roller 29away from the teeth 13, the member 25 rocks and'the bevel gear 8 is no longer driven in a'determinate-mannerby the drivingsha-ft;` In order to compensate for the'reaction of the driven load 'Y Aduring operation on the roller 29 engaged in the locking a support 31 act on the bar 23 and normally maintain Y v the control member in the inoperative position illustrated in Figure l, An auxiliary locking device comprising the member 25 mounted freely on a fixed pin 30 comprises a lever 26, which will be termed the active lever, because it is associated with the locking'teeth of the active bevel gear 8, and Ya lever 27, which will be termed the passive lever, because it is associated with the passive bevel gear 9. TheV lever 26 is provided with a rollerr28 illustrated in Figure l, which, is engaged in thelocking 7 teeth 12 of the active bevel gear 8. The lever 27 is prog vided with a roller 29 illustrated out of engagement with the lockingV teeth 17 of the passive bevel gear 9.

' l The driving shaft 1 turns in the directionof the arrow F Vand drives the planet wheels of the differential inthis movement. The roller 28 being engaged in the locking teeth12 of the active bevel gear 8, prevents the latter from turning. The planet wheels driven by theY driving shaft engage on the one hand with the toothed rim 6 of the bevel gear 8, which is locked by the roller 28, and on the other hand with the toothed rim 7 of the bevel gear 9, which is driven at a speedY of Yrotation twice the speed of rotationV of the driving shaft. v.By

the rotation of the bevel gear 9, the locking teeth 13V` of this kbevel gear urge the roller 29 out of engagement with the said teethr andthe thrust of the teethY on the saidy roller, by rocking vthe member 25, maintainsthe Yoccupied by the control members in theV course ofthe operation of the device are illustrated in the diagrammatic'Figures 5 to 10. The position of thecontrol memberin Figure 5 corresponds to thatof Figure ,1, which `g Starlingof the driving mechanism .'When thew'start'electromagnet 18 (Figure l) isnener'- gised, itcauses the locking of thetbevel gear 9 as already bevel gear 8, which is then setinV movement. The tooth Y explained. .The planet wheels 2, 3 which rotate continuoursly about the axis of the driving shaft, engage with their teeth in the toothed rim 7 of the bevel gear 9, which is held fast, and react on the teeth of the rim 61o'fthe 12av (Figures 41 and 6) Yof the teeth ,'12 forces ,the rollerV roller 29 engaged in the gap y11311 in the locking teeth 13 of the bevel gear 9, which is thus locked. From this i 12 in movement, by acting on the roller 28, maintain the instant, the energisation of the electromagnet 18 'may beV interrupted to allow fthe spring 21 (Figure 1)to1return the pawl 17 to the inoperative position. The resistduce through the planet wheels, reactions on the PaSSYe teeth of` th'e'fbevel 'gear 9 (Figure 8),.the locking lever 26 has been made with a length L greater than the length l of the locking lever Y27. yOwing to the difference in the lengthrof the levers, the roller V29 exerts on the locking teeth 113 a pressure stronger than the pressure exerted on the roller 28 by the locking teeth 12. In addition, the locking levers are so disposed that, in relation to the direction of rotation of the bevel gears, Vthe lever 27 is in abutment with-the teeth of thepassive bevel gear 9V.T A similar `condition is produced in the device illustrated in (Figurel-l, in whichV thecontrol member 14a and the locking devicev 25a consist of sliding members. VIn this arrangement, .the toothA .13C vof the bevel gear 9a abuts the roller-29a while the teeth 12C force the roller 28a in the direction of the arrow E.

Stopping of the driven mechanism A -'l`o stop the bevelfgear 8 andV thus the driven mechavthe pawl y16 (Figure-10j), a toothV gap 12rd is stopped in 4an appropriate position to receive the roller 28, which engages in the gap 12d due to the rocking of the member 25 under the action of vthe teetht13 of the vbevel gear 9, which forces the roller 29 outiof engagement. The pawl -16 can then kbe disengaged by'interruptionY of the energisation of the stop electromagnet 20. Sincethe bevel gear 9 has 4only to supply the elortnecessaryV to hold the roller 29 out of engagement and does not drive the mechanism, the reactions ofthe planet wheels on the bevel gear 8 are reduced and cannot force the Vroller 28 out of engagement. 'I'he Ydevice for actuating the control member illustrated in Figure 3 is equivalent to that illustrated for Ythe kcontrol of/atotalling wheel driving device in the aforesaid French PatentV No. 527,463. Mention has al- ,ready been made of the disadvantage of this arrangement, which requires-that the start Velectromagnet 18a `should be maintained in the energised condition throughoutthe time during which the mechanism coupled with Vtheactive bevel gear is to bedriven; .Figure 4 showsa control member `Ma'actu'ated bymeans of an electromagnetoperating with a polarisedblade. The Ycontrol member is provided with aV soft-iron shank or blade 32 which extends through anraperture 33'formed in a permanent magnet 34,51the north and. south poles of whichare marked N and S'res'pectively'. The blade 32 also extends throughan induction coil 35, and is maintained in the central inoperative position by a resilient device not shown. .When an electriccurrent is set up in the coil 35, the blade `is attracted either bythe north pole or by the south pole of thepermanent magnet, depending upon the direction ofthe current in the'coil, and thus'eiects the starting or stopping ofthe mechanism. A 'i When thedriving shaft Vlis, stopped-and Vwhen thedevice of Figure lis inoperative, andno locking pawl is engaged (in contrast .to what is the case with-the device illustrated-in Figure 3), the position-of the auxiliary .locking device is indeterminate and the Astarting of the drivingshaftcan .bringabout the' involuntary starting of jthefmechanismcoupled with Vthe .active bevel gear of theV differential,v A

- Y.' AInorder `to obviate this disadvantage, a brake is-'pro- Vances of themechanism driven by the bevel gear 8 provided whichconsistsr(Figures Sxand l2)Y ofa springY 'blade 36,`one end of which is xed to aV xed bar' 37.

The other end ofthe blade rubszon a portion of the memandere ber 25'so -as to maintain the said member, in the absence of any-other action, in the position in which it is situated when the driving shaft is stopped. Thus, when the driving shaft of the device is ite-started the latter starts again in the operative condition in which it was when the driving shaft was stopped. A similar device is illusstrated in Figure l1, in which a spring 38 maintains the sliding member 25a in the position into which it has been brought. In another arrangement illustrated in Figure 6, the member 25 is provided with a shank 38 whichr rocks between two magnetised bars 40 and 41 and is .magnetically held against one bar or the other depending upon the position into which it is brought under the action of ythe locking teeth of the bevel gears on the rollers of the locking levers.

Figure l2 illustrates in transverse section an accumulating mechanism for a record card accounting or statistical machine. eference may be made by way of indication to the French patent applied for on January 8, 1936, No. 811,724, and to the first addition to the said patent, applied for on February 12, 1936 and granted under the No. 47,642, in which there is shown an example of the use of accumulating mechanisms. An accumulating unit normally comprises 12 totalling wheels, each totalling wheel being coupled with a rotary distributor switch and with a system of cam-controlled electric contacts to close and open contacts controlling the carry-over circuits. ln order to deal with numbers comprising more than l2 digits, electrical connections may be established to combine a number of accumulators, and to deal with numbers comprising only a few digits the wheels of one accumulator may be used in groups of three or multipies or three wheels. In the accumulating mechanism illustrated in Figure 12, the mechanism by which. the totalling wheels are driven is that illustrated in detail in Figures 1 and 2.

ln the following description, identical members will bedesignated by the same references. The driving shaft 1 supports differential driving mechanisms comprising a bevel gear provided with teeth li meshing with a pinion 11 of insulating material, which is arranged to rotate freely on a pin 47. The said pinion supports the contacts 42 and 43 of a rotary switch. When the pinion is driven the said contacts travel successively over contact studs Si? to 59, which are thus successively electrically connected to a contact segment The contact studs and the Contact segment of each switch are connected to output studs PX, P1, P2, P9, P connected to the utilisation circuits of the machine (not shown). The Contact` studs, the contact segments and the connections to the output studs are constitutcd by printed circuits on insulating plates 45, 46 mounted on supporting bars iS-49, each insulating plate bearing the printed circuits of one switch on each face. The control members 11i are mounted on the supporting shaft and actuated by start and stop electromagnets 18 and 2i). The auxiliary locking devices comprising the members 2.5 are mounted on the shaft 3d. There also meshes with the teeth 10 a toothed pinion mounted freely on a shaft 62. Keyed on each pinion 6@ is a carryover c-am 61 which, when driven, pushes at each revolution a carry-over contact lever 63. Since the operation of the carry-over circuits of accumulators is known to the person skilled in the art, it will not be described. The supporting shafts 47, 3u, 15 and 62 are supported in the accumulator by side plates 72 and 73 (Figures 12 and 13). The side plates are connected by cross bars 64 and 65 and supporting bars 66, 67, 63, which support the stop electromagnets 243, the start electromagnets 18 and the insulating supports 74 of the carry-over contact blades respectively. The spring blades Se form brakes for the members 25. The said bars also form cross members `between the side plates of the accumulator. Keyed ontlie driving shaft 1 is a pinion 69 (Figure l3)driven a number of accumulatore.' Keyed on the pinion 77 meshing with the pinion 69 is aicam 78 which, at each revolution, actuates'the bars 79 for resetting the carryover contacts by acting onthe lever 1S through a roller 81 which is constantly applied against the can178 under the action of a return spring 82. For the sake of clarity, the bars y37, 48y and 64 (Figure 12) are not shown in Figurel4.

An accumulator provided with driving devices. designed in accordance with the invention may be employed directly for addition and for subtraction.

Figure 15 is a very simpliiied diagram illustrating the principle of the electric' circuits provided for this mode of use in a machine controlled by punched vrecord cards. The record cards are successively fedV into'the machine and pass in the direction of the arrow D under scanning brushes disposed in rows. The irst row, calledl the upper brush set BS, scans the control perforations indicating the operation to be carried out on values Iwhich are thereafter analysed during the passage of the card below the brushes of the lower brush set Bl. In the punched card partly illustrated in Figure 15, record perforations are formed in horizontal rows of value 9 to 0, 11 and 12 and in vertical columns. Each column thus comprising the positions for the perforations of value 9 to 0, ll. and 12 is scanned by a brush. All the perforations of like value are simultaneously scanned. The perforations for the number 2147 are indicated on the card in Figure 15.

A perforationv S in the row ovalue 12 may be utilized to control the subtraction of this number from a number` already introduced into anaccumulator. The arrangement of the contacts illustratedA in solid lines'corresponds to the arrangementfor the introductionY of a number during addition. A manually operable contact 91 permtis, when closed, of effecting the introduction of a number during subtraction after the scanning of' a perforation S during the passage of a card under the upper brush set. The contact 91 beingshown open, the introduction will be made for the purpose of addition. Thebasic circuits have been illustrated only for the brush 92 of the upper brush setBS and only for the brush 93 of the lower brush set BI. The operation of the circuits for the brushes scanning the other columns of perforations indicated is similar. For the addition, the passage of a perforation 4 under the brush 93 establishes the following circuit: from the positive pole of the curren source, through the line 94, the contact 95 closed by the cam 95e during theV passage of the record positions 9 to 0 of the card below the scanning brush set BI, through the contact' brush 96, the contact roller 97 and the perforation 4, the current ows through the brush 93, the line 98, the contact 99 and the start electromagnet 1S which is energised, the line 190 and the negative pole of the current source. The energisation of the start electromagnet at the instant of the scanning of the perforation 4 of the card starts vthe corresponding totalling wheel. This wheelY continues to rotate. synchronously @with the movement of the card until theY instant when the-row 0 of the card travels under the analysing brush. set. At this instant, the said wheel like all the other totalling wheels started during the scanning of a card, is stopped by the clossing of the cam cont-act 101', which establishes the' `following circuit: positive pole', closed cam contact` 101, contact 102, line 103, Contact 104, ystop electromagnet 20, line 100, negative pole of the current source. The totalling wheel started by the scanning of the perforation 4-has at this instantrecorded the value 4 in the tens order oftlie accumulator by turning the corresponding switch through four studs. For the subtraction, the process is'dilerent. It is known that Vit is possible to subtract one number from a larger number by the addition of the complement to 9 of each kdigit to-be subtracted and by effecting a carry-overfor correction of ther result. It is known' to effect such an addition of the complement inpunched-card. machines by rotating through pinions-71 and 75 bythe shaft 76,- which drives 75 thezfotalling. wheelsrat rheinstanpwhemthefrow ofI Per,

forationpos-itions of thevalue 9.of the card passes below the scanning brushes and to stop each ,wheell as Va result of the scanningof Ya perforation in a corresponding columnjof'theY card.V AnV accumulatorY in` which', the wheels are provided withthe Ydriving mechanismaccording to the invention lends itself with' advantage to. the perfomance of thesubtraction in th'e'aforesaid manner. An

Yaccumulator having six totalling wheels will bejconsidered,1 in which the number-42595 is alreadysituated.V

For Vsubtracrrting the Vnumber 2147 `from 'thisnumbeig it is necessary to add to"'42595A the Vcompleitnentto 9 of V 2147. "For `siX totalling wheels, this complement is 997,852.` The result of this addition is 1,040,447. YThis result is corrected 4by introducing into th units order the carry-over whichV would ktake up a position in a seventh totalling wheel. for the millions order. AThe corrected result obtained is 40,448V

I,}-997,852 (l) ,040,447 l In accordance with the diagram of Figure V15, the digit Y up Vthe position indicated in broken llines inthe diagram.

Theelectromagnet 109 is maintainedY energisedV by the contact 110 through the cam contact 111. Means not shown Vare provided to prevent the scanning of a control perforation in the following cardrfrom modifyingr the Y control circuits established for the preceding card. During the Vpassage belowY the brush set BI ofthe row of perforationk positions for the value 9 in the'card 90, the following circuit is'established': positive pole, cam con-A tact 112 (this contact closesronly at thepoint 9), contact 113, line 103, Ycontact 114, 'start electrom-ag'net 18, return to negative. vThe six Wheels'o'f vthe accumulator whichf'are allocated to the'subtraction start at the point 9 except those forwhich Va perforation 9 is scanned.Av YIn Vthis case, the simultaneous energisation'of the two electromagnets and 18 controlling a totalling wheel, has nov effect on the member controllingV this wheel. Thescanning of the perforatior'rlr in the card which is then effected by the brush 93 energises the electromagnet 20, which stops theitotalling wheel of the tens order which has at this instant adyancedY byve units. Before 'the' instant when theV row of positions for the perforations of'the value 0 in the card passes below theV brushes, the cam 111 interruptsthe holding of the relay 109'the contact blades 105 to 108 of which return to the position indi:l

cated in solid lines. .All the stop electromagnets 20 Vare energised by the'ca'm Contact 101, which closes at the point 0, andthe wheelswhich'have not been stopped by the scanning of a perforation situated Vin, aV row of value between 9 and O'are stopped.

, A'special kconnection feeds'Y o'the units'V order wheel (as already stated) the carry-over emanating fronrthe highest'order ofthe groupiof totalling wheels;

Y The wheel'of Vthe tens orderYV of the accumulator, advanced by five units, Vrepresents the tens digit of the re- Vsult and has produced the transmission Vof a carry-over, f j

. The embodiment fdescribed by way `of example isin Vno Vway limitative and the invention is applicable notably to selector-distributors employed in automatic. telephony nisms depending upon the circumstances andapplications without departing from the spirit ofY theinvention.v f* l LVA differential-driving mechanism comprisingtwo bevel gears mounted rotatable'on arcommon'shaflt, 'one or more planet/wheels, constantly engaged with said two bevelV gears, said planet wheelorj wheels being driven with a continuous rotational movement about ythe axis of said shaft, means connecting one bevel gear withone or more mechanisms'to'be driven,` first locking means comprising for each bevel ygear at least one set of locking teeth and a lockingrp'awl normallyheld out of en*- gagement with the'said lockingteeth, control means for said pawl comprising an electromagnet so Ydisposed that the temporary energisation of'said eleotromagnet brings said pawl into engagement with the locking teeth of the corresponding bevel gear lockingsaid bevel gear, said rst locking means being adapted to lock one'bevel gear orrthe other so that the unlocked bevel gear is rotated by the movement of the planet wheel or wheels, said control means being so arranged that the simultaneous energisation of the twoelectromagnets has no elfect on said pawls, and second locking means adapted to maintain the locked bevel gear in its locked position under the action of the movement of the locking teeth of the driven bevel gear. Y

2. A differential driving mechanism comprising [two bevel gears mounted rotatable on a common shaft, one or more planet'whcels constantly engaged with said two bevel gears, said planet wheel or wheels being driven with a continuous rotational movement about the axis of said shaft, means connecting one bevel gear with one or more mechanisms to be driven, irst locking means comprising for each bevel gear at least one set of Vlocking teeth and a locking pawl normally heldV out of engagement with said locking teeth, control means for said pawl compris-v ingpan electromagnet so disposed that the temporary energisation of said electromagnet brings said pawl Vinto engagement with the locking teeth of the corresponding bevel gear and lock said bevel gear, the unlocked bevel gear being rotated by the movement of the planet wheel or wheels, the lockingpawls of the bevel gears being rigidly fast with oneranotherV and mounted to rock about a fixed axis, a spring device normally maintaining said pawls out of engagement with the locking teeth of the y driven -bevel gear.

3; A Vdifferential driving mechanism comprising Vtwo bevel gears mounted rotatable on a common shaft, one or more planet wheels constantly engaged with said two bevel gears, said planet wheel or wheels being driven with a continuous rotational movement about the axis of said shaft, means connecting one bevel gear with one or more mechanisms to be driven, first locking means comprising for each bevel gear at least one set of locking teeth and a locking pawl normally held out of engagement with said locking teeth, control meansifor'said pawl comprising an electromagnet so disposed that the temporary energisation of said electromagnet brings said pawlinto engagement with` the locking teethv of the corresponding and to all like devices, and'any modicationsin theform and arrangementof the parts may be made in the mechav bevelV gear, locking said bevel gear, the unlocked bevel gear being rotated by the movement of the'planet wheels, the'locking Vpawls Vbeing rigidly fast with one another on a support sliding along an'axis and disposed sothat said locking pawls can not be simultaneouslyV brought in engagement into the locking teeth of the bevel gears,

a spring device normallymaintains the said pawls out'of p 4. A dilferential driving mechanism comprising-,two bevel gears mountedrotatable on -a common 's haft, one

or more planet wheels, constantly engaged with the said two bevel gears, said planet wheel or wheels being driven with a continuous rotational movement about the axis of said shaft, means connecting one bevel gear with one or more mechanisms to be driven, first locking means comprising for each bevel gear at least one set of locking teeth and a locking pawl normally held out of engagement with said teeth, control means for said pawl comprising an electromagnet so disposed that the temporary energisation of said electromagnet brings said pawl into engagement with the locking teeth of the corresponding bevel gear, locking said bevel gear, the unlocked bevel gear being rotated by the movement of the planet wheel or wheels, the locking pawls being fast with a -blade adapted to rock about a `fixed axis and situated within an induction coil disposed between the arms of a permanent magnet so that when a current is passing through the induction coil in one direction or in the other the blade is attracted towards one arm of the permanent magnet or the other and one locking pawl or the other is brought into engagement with the locking teeth of the corresponding bevel gear, thus starting or stopping the driven mechanism in accordance with the direction of the current through the induction coil, and second locking means adapted to maintain the locked bevel gear in its locked position under the action of the movement of the locking teeth of the driven bevel gear.

References Cited in the le of this patent UNITED STATES PATENTS 2,078,161 Rietsch Apr. 20, 1937 2,444,566 Hennessy et al July 6, 1948 2,558,953 Henninger et al. July 3, 1951 2,770,145 Stibitz Nov. 13, 1956

Images