US1394098A

US1394098A - Tractor

Info

Publication number: US1394098A
Authority: US
Publication date: 1921-10-18
Anticipated expiration: 1938-10-18

Description

I. L. LAKE AND F. o. McMAHON.

' TRACTOR. APPLICATION FILED JUNE I4, 1911- 1 .394 O98 Patented Oct. 18, 1921;

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l. L. LAKE AND F. D. McMAHON'.

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1,. L. LAKE AND F. D. McMAHON.

TRACTOR.

APPLICATION FILED JUNE I4. 9H.

1,394,098. Patented Oct-18,1921.

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I I fihajilala ma I I WW? J. L. LAKE AND F. D. McMAHON.

TRACTOR.

APPLICATION FILED JUNE 14, 1917.

1,394,098, Patented Oct 18,1921.

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} TRACTOR.

APPLICATION FILED JUNE 14, I917. 1,394,098, Patented Oct. 18, 1921.

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' M m M M J. L. LAKE AND FLD. McMAHON. TRACTOR.

I APPLICATION FILED JUNE 14. 1911.

1,394,098, Patnted 00a 18, 1921,

15* Z If i D UNITEDYSTATES PATENT OFFICE.

'J'OHN L. LAKE AND FRANCIS D. MCMAHON, 0F CLEVELAND, OHIO.

TRACTOR.

' Application filed June 14,

To all whom it may concern:

Be it known that we, JOHN. L. LAKE, a subject of the King of Great Britain and a citizen of the Dominion of Canada, and FRANCIS D. MCMAHON, a citizen of the United States, both residing at Cleveland, in the county of Cuyahoga and State of Ohio,

' have invented a certain new and useful Improvement in Tractors, of which the following is a full, clear, and exact descript on, reference being had to the accompanying V drawings.

This invention re'lates'to improvements in tractors, particularly of-the line drive variety and of the type having two largev traction wheels from which is suspended practically the entire weight of the driving motor, mechanism and frame, thereby to enhance the traction. i

The generalobjects are the attainmentof simplicity and accuracy in the control of tractors of the above class, while maintaining the maximum of efiiciency.

More specifically, the invention has for its objects the provision of means, simple of construction and sure of operation for driving a tractor of the character aforesaid in reverse directions, at variable speeds, and for turning the tractor; and the accomplishment of. these ends by the use of two main lines and two auxiliary lines; the provision of cams shiftable by the use or lines in one direction and by tension means, as springs, in the opposite direction, for actuating clutches in the attainment of the immediatelyforegoin results; and the inclusion of novel means for maintaining the clutch actuating cams in various shifted positions.

In tractors of the class above referred to, the traction wheels carry large gears arranged concentric to the wheels and with which driving pinions mesh, while the main structure. is spring suspended from the axle of the wheels. A further object of this invention is the provision of a construction enabling the frame to swing with respect to the axle of the wheels on an are described from the center of the driving pinions, wherefore a proper meshing of the pinions and gears is constantly maintained.

The foregoing, and other objects which will become apparent as this'description proceeds, are attained in the construction illustrated in thedrawings accompanying and forming a parthereof, and wherein similar Specification of Letters Patent.

' Patented Oct. 18, 1921. 1917.. Serial No. 174,686.

reference characters designate correspond ing parts throughout the several views.

In the drawings, Figure 1 is a plan View of the tractor; Fig. 2 is a centrallongitud nal section through the tractor (the engine, radiator, "etc., being shown in elevation); Fig. 3 is a fragmentary transverse section through the tractor on the line 33 of Fig. 2, the plane of the section being indicated by the correspondingly numbered l ne of Fig. 4; Fig. 4 is a horizontal section through thetransmission gear casing and the fly wheel of the engine, the section being taken on the lines 44L of Figs. 2 and 3; Fig. 5 is a vertical section on the lines 5-5 of Figs. 1 and 3; Fig. 6 is a transverse section through the change-of-speed gearing, the same being taken on the lines 6-6 of Figs. 1 and 4; Fig. 7 is a sectional detail on the line 77 of Fig. 6; Figs. 8 and'9 are sectional details on lines 88 and 9-9,. respectively, of Fig. 1; Fig. 10 is a perspective view of the parts shown in Fig. 9 in separated condition; Fig. 11 is a perspective view ofmechanism for shifting the clutch-pinions. through which forward and reverse drives of the traction wheels are obtained; andFig. 12 is a similar view of one of the friction clutch actuating cams.

The traction wheels which are designated 1 are loosely mounted upon the ends of an axle 2 from which the frame is suspended.

The frame is made up of an upper section and a lower section 5 that are connected and spaced apart by lacing members 6. It will be seen, particularly from Fig. 1, that the opposite sides of the lower frame section 5 are spaced a like distance apart throughout their lengths, while the sides of the upper frame section are bent outward just forward of their longitudinal centers and extendrearwardly across the axle 2 just inside the traction wheels. The frame 4 is made of outwardly opening channels, and secured toit', preferably by rivets 7, justabove. the aXleare spring buttresses 8 from which depend guides 9 that are spaced apart and are curved on arcs described from the center of the driving shafts presently to he described. A bearing block 10 is mounted for reciprocation between the guides 9 of each buttress and within the blocks 10 is journaledthe axle 2. A spring support 12 is applied to the axle outside of each block 10, the support being split for application to the shaft and adapted to be clamped firmly thereto by bolts 13 which pass through apertures in opposed ears 14 of the support. Each support is provided with spring seats between which and the overhanging portions of the buttresses 8 are adapted to be confined springs 15. A plate 16 is secured to the lower ends of the guides 9 by screws 17 to prevent the withdrawal of the blocks 10. A radiator 20 is supported by the forward end of the frame, and an internal combustion engine 21 of any approved type, is carried by the lower frame section 5 immediately to the rear of the radiator. It is customary to employ a governor for controlling the engine speed in tractors of this sort, and this practice may be followed in the present instance. As shown in Fig. 4, the engine shaft 22 is equipped with a fly wheel 23 and has connection, through an O ldham coupling 24, with the forward end of the driving shaft 26. The transmission gear case 28 is supported, to the rear of the engine, by the lower frame section 5, and formed integral with this case is a worm casing 29 and the lower half of the worm wheel casing 30. The driving shaft extends through the front removable wall 31 of the gear case, in alinement with the worm shaft 32 that is supported within the worm casing 29, the shafts being journaled within suitable bearings 83 where they pass through the walls of the casing, the extreme rear end of the worm shaft being equipped with a thrust bearing 34 that is backed up by a plate 35, secured to the rear recessed end of the casing by screws'36. The rear end of the driving shaft is piloted within the forward end of the worm shaft, as indicated at 38, and adjacent its rear end, the driving shaft is squared at 39. A double faced clutch member 40 is slidable upon the squared portion '39, and is adapted to be shifted forwardly into coijperation with the clutch face 41 of a gear 42, loosely mounted upon the driving shaft or rearwardly into coiiperation with the clutch face 4-3 of a tl that is secured by the key 45 to the forward end of the worm shaft. A shaft 16 has its ends supported in the front and rear walls of the gear case 28, and loosely mounted upon this shaft is a hub 48 common to two gears a9 and 50, the former meshing with gear 412, and the latter with gear 44t- A gear 52 is keyed to thedriving shaft forward of the gear 12 and meshes with a gear 53 that isloosely mounted upon a shaft 5% supported with its ends in the front and rear walls of the gear case. The rear end of the elongated hub 55 of the gear 53 is squared, and a clutch member 56 is slidably mounted upon this squared portion of the hub for cooperation with a clutch face 57 of a gear 58 that is loosely mounted upon the shaft 54 and meshes with the gear 44.

t may be explained at this time that when the clutch member 40, is shifted forwardly it locks the gear 42 to the driving shaft, and this gear, through the

gears

49 and 50 will drive the gear 44, and consequently the worm shaft, at a reduced speed with respect to the driving shaft. T he speed of the driving shaft may be transmitted to the rear shaft by shifting the clutch member d0 rearwardly into engagement with the clutch face 43 of the gear 44. To drive the worm shaft at an increased speed over that of the driving shaft, the clutch member 56 may be shifted into co6peration with the clutch face 57 of the gear 58, for it will be observed that the gear 52 is keyed to the driving shaft and is, therefore, constantly rotating with it, and its motion is transmitted through the gear 53, clutch member 56 and gear 58, to the gear 44 of the worm shaft, the ratio of the gears being such as to cause an increase over the speed obtained through the gear combinations previously described. Clutch'members 4:0 and 56 are shifted by mechanism which will now be described.

Referring particularly to Figs. 6 and 7, 60 is a plate that is slidably mounted within guides 61 in the top portion of the gear case 28. Just below the plane of the plate,

rods

62 and 63 are slidably supported. within the front and rear walls of the gear case, and the former has clamped to a fork 65 which embraces the clutch member 40, while the latter has secured to it a fork 66 which embraces the clutch member 56. Clamped to the

respective rods

62 and 63 are arms 68 and69, the former carrying an anti-friction roller which is arranged to traverse a cam slot 70 and the latter a friction roller arranged to traverse a cam slot 71, in the plate 60.

In the position shown in Fig. 7, the clutch members are in neutral position and the rollers of the arms 68 7 shall be termed neutral portions of the slots 70 and 71, the neutral portions of the slots being shown as substantially coincident with the longitudinal axis of the plate. When the plate 60 is moved to the right, it will be seen that a portion of the slot 70 which is inclined forwardly from. its neutral portion will embrace the roller of the arm 68 and through said arm shift the rod 62, with the fork 65 and clutch member 40, forwardly to obtain what I have already referred to as low speed. During this movement of the plate. the clutch member 56 will remain idle for there is no divergence from the neutral zone of the slot 71. The plate may be shifted a given distance to the left without affecting the clutch member 56, but upon such movement of the plate, the fork 65 will be shifted rearwardly because of the rearward inclination of the slot 70 just to the right of its formerly mentioned neutral and 69 occupy what portion, and in so shifting the fork 65 and the clutch member 40, what may be termed second speed is obtained, as above explained. Upon a further movement of the plate to the left, the adjacent forwardly inclined portion of the slot 70 returns the fork 65 and clutch 40 to neutral position, while a rearward extension of the slot 71 causes the fork 66 and clutch member 56 to be shifted rearwardly in the attainment of high speed. 'The plate 60 is moved to the left by a spring 73 which has one of its ends anchored at 74 to the gear case, while its opposite end is secured at 75 to the plate. The plate is adapted to be shifted against the action of this spring by a line 76 which is secured to one branch of a bell crank lever 77 that is pivoted at 7 8 to the plate 60. The opposite end of the bell crank lever has a nose 7 9 that is adapted to be projected into notches 80 in the side of the adjacent guide 61, by a spring 82 which, it may be said, is considerably weaker than the spring 73. Each of the notches 80 represents one effective position of the plate 60. When the line 76 is pulled, it first withdraws the nose 79 ofv the bell crank lever from a notch 80, and a. further pull upon the line will shift the plate to the right. By relaxing the line rather gradually the bell crank lever may be held with its nose withdrawn beyond the plane of the notched guide 61, which will enable the plate to be shifted its full movement to the left by the spring 73 if such is desired. On the other hand, should it be desired to arrest the movement of the plate at any one of the notches 80, the plate may be shifted so that the nose of the bell crank 1s tothe right of the desired notch, and then, by quickly releasing the line, the nose will be thrown against the edge of the guide 61 and will be projected into the notch by the spring 82 instantly upon its reaching the same.

A worm 85, upon the worm shaft 32, meshes with a worm wheel 86 that is housed within the casing 30 and is keyed to the shaft 87 which extends transversely of the machine and is journaled within bearings 88 that aremounted within the sides of the casing 30. The ends of the shaft 87 project just outside the casing where they have keved to them the external members of frictidn clutches 90. The internal member 91 of each of the friction clutches is splined to a short shaft 92 which has its inner end piloted within the adjacent end of the shaft On each side of the machine and in the vertical plane of the shafts 92, is supported a hollow shaft 100 within bearings 101 and 102. The latter bearing is suspended from a cross-brace 103 on the upper frame section 4, while the former is contained within a housing 104 that is suspended from the frame section 4 at the junction of the cross brace 103. A pinion 105 is keyed to the shaft 100 and meshes with the pinion 95 of the adjacent shaft 92. Slidably mounted upon the extreme outer end of each shaft 100 is what may be termed a clutch-pinion 108, the same being splined to the shaft through the feather 109. The teeth of the pinion are represented at 110 and the pinion carries on its inner side a clutch face 111 for cooperation with the clutch face 112 of what I shall term a bull pinion 113. This pinion is made up of a hub portion 114, which is rotatably mounted upon the shaft 100, and from which extend circumferential longitudinally spaced flanges 115 between which are mounted anti-friction rollers 116,

the inner flange being shown as cored to provide a lubricant chamber 117 that is adapted to be supplied with oil through an oilcup 118. The bull pinion constantly meshes with a bull gear 120 supported from the rim of the adjacent traction wheel 1 by brackets 121, the bull gear being an internal gear as clearly shown in Fig. 2. When either of the clutch-pinions 108 is in its extreme outer position its teeth 110 mesh with an external gear 125 which is carried by extensions 126 of the brackets 121, the gears 125 being referred to hereinafter, because of their function, as the reversing gears. The clutch-pinions 108 have a neutral position when they neither cooperate with the reversing gears 125 nor the clutch facesof the bull pinions. A cylindrical casing 128 is carried by the :bull pinions and incloses the clutch-pinions except when the latter are in mesh with the reversing gears.

A rod 130 extends through the bore of each shaft 100, and near its outer end has a transverse groove 131 which receives the inner end of a finger 132 that is secured to the clutch-pinion 108 and projects through a slot 133 in'the shaft. The bore of the shaft is enlarged at its inner end to receive a rider 135 which is swiveled to the adjacent end of the rod 130, and between a thrust bearing 136, which bears against the inclosed end of the rider, and the opposed annular wall of the enlargement of the bore, there is inter posed a spring 138 which tends to move the rod inwardly and carry the clutch-pinion into cooperation with the clutch face of the bull pinion 114.-

Supported by hangers 140, from the crossbrace 103, just inside the inner ends of shaft 100, is a pair of plates 141 between which is guided a cam 142, the cam face whereof is arranged for cooperation with a roller 148, carried by the rider 135. This cam, with its supporting structure, is shown in detail in Fig. 11. The cam is adapted to be stopped in three positions by a pawl 145 which is pivoted between two ears 1&6 rising from the upper plate 14:1, the nose of the pawl playing within a slot 14:? in the top plate and adapted to enter any one of three recesses 1 18 in the cam. The cam has three face portions 142, 1 12", and 1 12, the portion 142 constituting what may be termed the neutral face of the cam, for, when the roller 1 13 is in engagement with this face the rod 180 is positioned to maintain the clutch-pinion 108 out of engagement with the reversing gear 125, and free from the clutch face 112 of the bull pinion. A line 150 is attached to the rear end of each cam 142, and by this line the cam may be drawn rearwardly against the tension of a spring 151 (Fig. 5) interposed between a dependinglug 152 of the cam and a projection 153 of the lower plate 141, the projection being 'apertured for the free passage of a rod 15a which has its forward end secured in the lug 152 and which serves to maintain the aforesaid spring in place. By a jerk upon the line 150 thepawl 1 15 may be rocked on its pivot to withdraw its nose from the intermediate recess, the pawl being rocked by engagement with the forward wall of the recess. The pawl is so nearly balanced that before it has time to resume effective position, the line may be released sufficiently to allow the spring 151 to move the cam forwardly so that the face 1 12 is brought into engagement with the roller 1423 allowing the clutch-pinion to engage the clutch face of the bull pinion and thus lock the bull pinion to the shaft 100. By drawing the cam to the extreme limit of its backward movement, where it is held by the pawl 14 engaging the forward recess 1 18, the face 1 12 is brought into engagement with the roller 1 13 whereupon the rod 130 will be projected outwardly to carry the clutch pinion into mesh with the reversing gear 125.

Remembering that the foregoing mechanism is duplicated with respect to both traction wheels it will be seen that-,by means of lines 150, the tractor may be driven forward, stopped, reversed, or by retaining one clutch-pinion in neutral position while engaging the other with the bull pinion or reversing gear, the tractor may be turned; or

again by allowing one of the clutch-pinions.

to mesh with the reversing gear and the other to cooperate with the bull pinion, the tractor may be spun around practically in its own tracks. lrlowever, there are situations which require a nicer and more accurate control than that afforded by the more 1 ,seapee shifting of the clutch-pinions, and for this reason the friction clutches 90 are employed. By means of these clutches the drive through either traction wheel may be rendered more or less positive or null as desired. These clutches provide what may be regarded as a manually controlled differential movement between the traction wheels. They are ac'tu ated by a mechanism which will now be described.

The branches of a fork 158 are connected to the shifting collar 159 of each clutch menibor 91. and the fork is fulcrumed upona vertical pin that is supported in the outer ends of arms 160 extending from the adjacent side of the wormwheel casing 30. rrroller that is carried by the shank of each fork reposes within the groove of a segmental cam 161, clamped or otherwise secured to a rock shaft 162, journaled within bearings 163. As shown in Figs. 1 and 12, the groove of each cam has a straight portionthrough which the roller of the shifting fork may play with no effect; but the lower end of the groove of the right hand cam (looking forward in Fig. 1) is inclined inwardly so that upon rocking the cam upward the rear end of the fork will be swung inwardly to move its opposite end with the clutch member 91, outwardly against the tension of the spring 96, thereby to disengage the member 91 from the (triving member of the clutch. In the case of the left hand cam, the upper end of its groove is inclined inwardly so that by rocking this cam downwardly the same result as that described in connection with the right hand clutch is now obtained in the left hand clutch. A comparatively strong spring 16% is coiled about the left hand end of the shaft 162 and has one of its ends attached to the sh ft and the other attached to a sector 165 which. as shown most clearly in Fig. 8, is carried by plate 166 secured to and extending between the rear ends of the frame sections i and A lever 168 is fastened to the left hand end of the shaft 162 adjacent the sector 165 and its upper end has pivoted to it a bell crank 169, and a line 170is secured to the free end of the vertical arm of the bell crank. The outer end of the other arm of this bell crank has a nose 171 adapted to enter one of the three notches 17 2 of the.

sector, and a spring 173 tends to swing the bell crank in a direction to project its nose into the notches.

From the foregoing it will be seen that when the line 170 is pulled, the bell crank will be rocked to release the arm 168 from the sector, so that the shaft 162 may be rotated in one direction by the spring 164: and in the opposite direction by the line 170. By

ing the arm rearwardly from its intermediate position the shaft 162 will be rocked in a direction to render the right hand clutch )0 ineffective, and when the shaft is permit ted to be rotated in the opposite direction by the spring 164, the left hand clutch is rendered ineffective- It is clear that the arm 168 maybe stopped inany of its three positions by carrying it far enough beyond the position desired to allow the nose of the bell crank to swing into engagement with the periphery of the sector before it reachesthe desired notch on its return movement, so that as soon as it does reach such notch it will be projected thereinto by the spring 173, the line 170, of course, having been fully released. To assist the operator in determining thethree positions of the arm, a plunger 175, set in a boss of the arm and spring pressed against the surface of the sector, is arranged to enter one of three depressions 17 6 in the sector, the location of r the depressions corresponding to the three positions. As the plunger passes the depressions it may readily felt by the operator. v

The fork 184 of a caster 185 is journaled within a vertical boss 186 of a frame 187,

' said frame comprising an upper and a lower branch each ofwhich has its forward end bifurcated for the reception of a flange 188 of the respective upper and

lower frame sections

4 and 5. A series of holes are formed in each ofthe flanges 188 so that the frame 187 maybe shiftedlaterally as desired to accommodate the draw bar of the drawn implement or 'vehicle. To prevent the frame-187 from swinging sidewise, a brace rod 190 has its rear end attached to a 1ug191 of the boss 186 and its forward end secured in any one of the holes in the horizontal flange of an angle bar 180 attached to the plate 166. spring 192 is incorporated in a well known manner in the connection be tween the caster fork and boss 186 to afford a yielding connection between'the two so as to partially absorb the shocks of the road. When the implement or vehicle to be drawn is of such nature as to maintain the rear end of the tractor frame at about normal elevation, the caster'and frame 187 may be dispensed with and. the draft mechanism of the implement or vehicle connected directly to the flanges 188.. A seat 194 is carried, through an arm 195, from the boss'186 in convenientposition for'the driver who may place his feet upon rests 196 which extend from the sides of the boss. The lines 150 may be led backward throughapertures in the plate 166 within easy reach of the drivers seat. 'The line 76, which controls the'cam plate 60 of the transmission gear, and the line 170, through which the cam shaft 162 may be rocked for releasing the clutches 90, are herein shown as a continuous cable which maypass rearwardly through apertures-inthe plate166'and around rollers 19?: and throughan eye 198 which rises from the arm-19.5 immediately in" front of 'the drivers seat, so that the line may be in easy reach of the. driver at all times.

As will be seen upon referring to Fig. 4, a beveled gear 200 is' keyed to the rear end of the worm shaft 32, and meshes with a similar gear 201 which has its hub j ournaled within a bearing 202 in the side of the wormcasing 29. A square socket is formed in the hub of the gear 201 and receives the corre spondingly shaped extension 203 of a shaft 204 which. is supported in a journal box 205 secured to the side of the frame section 5; and beyond this journal box the shaft has appliedjto it a belt pulley 206. Through this means, power may be derived from'the tractor for driving such apparatus as threshing machines, cement mixers, etc; The connection between the shaft 204 and gear 201 allows an easy removalof the shaft by simply loosening the collar 208. (normally located just inside the journal box) and withdrawing the shaft endwise through its bearing. In cases where the pulley is not needed it may be desirable to remove it entirely.

An example of the liner for the bearing housings, eliminating theboring ormachining of the housings to produce a finished interior for the reception of the bearings, hereinbefore set out as a feature of theinvention, is found associated with the bearings 88 and 101 in Fig. 3. In each instance, the liner is designated 210. In. lining the housings, they are arranged with their open side uppermost and a mandrel, having the size and shape of the bearing that is to occupy the housing, is supported in proper position within each housing, after which molten material, such as babbitt, is poured about the mandrel and allowed to harden, after which the mandrel may be removed, leaving the interior of the housing smooth and com pletely finished ready to receive the bearing. Thus rough castings may be quickly prepared for use without the need of any tool work whatever. 7

Having thus described our inventi'onfwhat shaft, driving connections between the shaft and motor, a pinion loose on the shaft and n mesh with one of said gears, a second pinion non-rotatable but slidable upon the shaft into and out of mesh with the other gear, said pinions having clutch faces arranged for engagement with each other, and mechanism for shifting the second pinion.

the combination of a motor, a traction wheel,

an internal and an external gear through whichsaid wheel may be driven, a shaft, drlving'connections between said shaft and 2. In apparatus of the character set forth,

the motor, a pinion loose on said shaft, and in mesh with one gear, a second pinion nonrotatable but slidable upon the shaft, said pinion's having complementary clutch faces, means tending to shift the second pinion with its clutch face in engagement with the clutch face of the first pinion, and means whereby said pinion may be shifted in opposition to the aforesaid means to an ineffective position or into mesh with its respective gear.

3. In apparatus of the character set forth, the combination of a motor, a pair of opposed traction wheels, a set of two gears through which each wheel may be driven, a shaft associated with each set of gears, driving connections between the motor and said shafts, a pinion loose on each shaft and meshing with one of saidgears, a pinion slidable upon but non-rotatable with respect to each shaft, said pinions of each shaft having complementary clutch faces, the second pinion being shift-able into mesh with its respective gear, or with its clutch face in engagement with the clutch face of the first pinion, or to an ineffective position, means tending to maintain each of the second pi-nions in one of said positions, and further means whereby said pinion may be shifted to either of its other positions.

4. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a pair of gears through which each wheel may be driven, ashaft associated with each pair of gears, driving connections between the motor and each shaft, a pinion loosely carried by each shaft and meshing with one of said gears, a second pinion slidable upon but non-rotatable with respect to each shaft, the pinions of each shaft having complementary clutch faces, a reciprocable member through which each of the second mentioned pin-ions may be moved into mesh with its respective ear or with its clutch face cooperation with the clutch face of the first pinion or to an ineffective position, a cam for reciprocating the aforesaid member, and further means for moving 'the'ca-m in reverse directions.

5. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a pair of gears through which each wheel may be driven, a shaft associated with each pair of gears, driving connections between the motor and each shaft, a pinion loosely carried by each shaft and meshing with one of said gears, a second pinion slidable upon but non-rotatable with respect to each shaft, the pinions of each shaft having complementary clutch faces, a reciprocable member through which each of the second mentioned pinions may be moved into mesh with its respective gear or with its clutch face in cooperation with the clutch face of the first pinion or to an ineffective position,

a cam for moving each of the reciprocable members, means tending to move sa1d cam in one direction, and further means for moving the cam in opposition to the first mentioned means.

6. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a pair of gears through which each wheel may be driven, a hollow shaft associated with each pair of gears, driving connections between the motor and each shaft, a pinion loosely mounted upon each shaft and meshing with one gear, a second pinion slidable upon but non-rotatable with respect to each shaft and adapted to mesh with the other gear, said pinions having cornplementa ry clutch faces, a rod reciprocable within said shaft, connections between the rod and second pinion, a cam for moving the rod thereby to shift the second pinion,means tending to move the cam in one direction, and means through which the cam may be moved in opposition to the first means.

7. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a pair of gears through which each wheel may be driven, a hollow shaft associated with each pair of gears, driving connections between the motor and each shaft, a pinion loosely mounted upon each shaft and meshing with one gear, a second pinion slidable upon but non-rotatable with respect to each shaft and adapted to mesh with the other gear, said pinions having complementary clutch faces, a rod reciprocable within said shaft, connections between the rod and second pinion, means impelling said rod in one direction, a cam for moving the rod in a reverse direction, and means for reciprocating thecam.

S. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a pair of gears through which each wheel may be driven,-a hollow shaft associated with each pair of gears, driving connections between the motor and each shaft, a pinion loosely mounted upon each shaft and meshing with one gear, a second pinion. slidable upon but non-rotatable with respect to each shaft and adapted to mesh with the other gear, said pinions having complementary clutch faces, a rod reciprocable within said shaft, connections between the rod and second pinion, me'jans impelling said rod in the direction to shift the second pin-ion with its clutch face in, cooperation with the clutch face of the first pinion, a cam for moving the rod in a reverse direction, means tending to move the cam in one direction, and means for moving said cam in the opposite direction.

9. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a shaft through which each Wheel is driven, transmission gearing operatively connected to the motor, a clutch for each shaft and through which said shaft may be coupled with the transmission gearing, common means for controlling said clutches movable in opposite directions to render the respective clutches ineffective, means tending to move the controlling means in one direction, and flexible means for moving said. controlling means in the opposite direction.

10. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a shaft through which each wheel is driven, operative connections between the motor and each shaft, said connections involving a clutch for each shaft, means tending to maintain each clutch in effective condition, controlling means mov able in opposite directions to render the respective clutches ineffective, means tending to move the controlling means in one direction, a device for moving the controlling means in the opposite direction, means acting automatically to retain said device in various positions, and further means for rendering said retaining means ineffective and for moving the device in opposition to V the former moving means.

11. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a shaft through which each wheel is driven, operative connections between the motor and each shaft, said con nections involving a clutch for each shaft, means tending to maintain each clutch in effective condition, controlling means movable in opposite directions to render the respective clutches ineffective, means tending to move the controlling means in one direction, a device for moving the controlling means in the opposite direction, a graduated retaining member, a pawl movably carried by the device for cooperation with said retaining member, means tending to hold said pawl in effective condition, and further means for rendering said pawl ineffective and for moving the device in opposition to the aforesaid moving means.

12. In apparatus of the character set forth, the combination of a motor, opposed traction wheels, a driving shaft for each wheel, operative connections between the motor and shafts, said connections involving a clutch for each shaft, means tending to maintain each clutch in effective condition, a rock shaft, cams upon said rock shaft one for disengaging one clutch when the shaft is rocked in one direction, and the other for disengaging the other clutch when the shaft is rocked in the opposite direction, a spring tending to rock the shaft in one direction, an arm secured to said shaft, a pawl pivotally connected to the arm, a sector having pawl engaging notches, a spring tending to rock the pawl to engaging position, and means connected with the pawl for rocking it in opposition to the last mentioned spring and through which said arm may be rocked in opposition to the first spring.

13. In apparatus of the character set forth, the combination of a motor, a traction wheel, a gear for driving said wheel in a forward direction, a second gear for driving the wheel in a reverse direction, a shaft, driving connections between the shaft and motor, a member shiftable upon said shaft for operatively connecting it with'the first or second gear, a reciprocable element for shifting said member in opposite directions, a cam for reciprocating said element, means tending to move the cam in one direction, further means for movlng the cam in op-' .POSltlOIl to the last mentioned means, a device for maintaining the cam in various positions against the action of the first mentioned means, said device being rendered temporarily ineffective upon the operation of the second mentioned cam moving means.

14. In power transmitting mechanism involving a driving member and a driven member, and means for effecting a driving connection between said members, a shiftable plate actuating said means, said plate having a plurality of apertures therein, a pivoted retaining device adapted to enter said apertures as said plate is shifted, said device being rendered temporarily ineffective by the movement of said plate in one direction, and means for moving said plate in reverse direction.

15. In power transmitting mechanism involving a driving member and a driven member, and means for effecting a driving connection between said members, a shif able plate for actuating said means, means tending to move said plate in one direction, a retaining device pivotally supported in operative relation to said plate for cooperation therewith to hold said plate in various positions against the action of the second mentioned means, and means for moving said plate in the opposite direction, the.

plate having portions for engaging and swinging said device temporarily from effective position when said plate is moved by the last mentioned means.

In testimony whereof, we hereunto affix our signatures.

JOHN L. LAKE. FRANCIS D. McMAI-ION.