USRE18842E

USRE18842E - Change speed mechanism

Info

Publication number: USRE18842E
Authority: US
Publication date: 1933-05-30

Description

C. H. RICHARDS CHANGE SPEED MECHANISM v Re. 18,842

4 Sheets-Sheet 1 May 30, 1933.

Original Filed Nov; 18. 1929 1 INvE E1 ET W.Oa w dv-Q 673 ATTYE C. H. RICHARDS CHANGE SPEED MECHANISM 4 Sheets-Sheet 2 May 30, 1933.,

Original Filed Nov. 18, 1929 c. H. RICHARDS CHANGE SPEED MECHANISM Re. 18,842

May 30, 1933.

4 Sheets-Sheet 3 Original Filed Nov. 18. 1929 C. H. RICHARDS CHANGE SPEED MECHANISM 4 Shgets-Sheet 4 May 30, 1933.

Original Filed Nov. 18, 1929 Reiuued May 30, 1933 CARROLL H. RIGKABDB, OF STOW, MASSACHUSETTS CHANGE SPEED MECHANISM Original 170. 1,883,399, dated October 18, 1882, Serial No. 407,820, filed November 18, 1929. Application for reissue filed March 6,

This invention relates to change-speed mechanisms and particularl to such mechanisms as applied to motor ve icles and known as transmissions or gear sets.

Motor vehicle transmission now in common use require'a manual shifting of gears to obtain the proper speed reductlon. This'shifting of gears is done by hand, thereby necessitating the removal of one hand from the steering wheel while the vehicle. is in motion. Due to present day conditions of heavy traffic, especially in thickly congested areas, and the a use of high speed motors with relatively faster pick-up or acceleration, it is essential for the operator to havev complete control of the car at all times, and in so doing to have both hands on the steering wheel to meet any emergency, and not only. make it safer for himself but to insure the safety of others.

Furthermore the present day transmissions are limited as to reductions, the operator of a motor vehicle having a choice of only a limited number of speeds which are approximate only in their performance besides requiring as manual operation.

The particular object of the present invention is to provide a speed change mechanism which will be automatically controlled by the resistance encountered and permitthe power to remain the same while the speed delivered is increased or decreased proportionally to the resistance. Such a construction would permit an engine to operate at its most efficient speed to deliver its maximum power while permitting the car to travel at maximum speed-on each grade for the power developed.

While a device of this character is particularly adapted for use in motor vehicles, it may equally well be adapted for use in other machines where speed reductions are necessary, such as machine tools, gun turrets and the like The foregoing and other objects of the in vention, together with means whereby the latter may be carried into effect, will best be understoood from the following description of the embodiment thereof illustrated in the accompanying drawings. It will be understood however that the particular construc- 1933. Serial in. 659,858.

tion and arrangement described and shown have been chosen for illustrative. purposes merely, and that the invention as defined by the claims hereunto appended, may be embodied in numerous other forms without departure from the spirit and scope thereof.

In said drawings: Fig. 1 is a diagram illustrating the operatlng principle of the invention in its highspeed condition.

Fig. 2 is a diagram illustrating the operating principle in its low-speed condition.

Fig. 3 is a plan view partly in section of a change-speed mechanism constructed and operating in accordance with said principles. Fig. 4 is a section taken on line 44 of Fig. 3.

Fig. 5 is a section taken on line 5-5 of ig. 6 is a section taken on line 66 of Fig. 3. I FFig. 7 is a section taken on line 77 of "ig. 8 is a view similar to Fig. 3 showing a modified construction. Fig. 9 shows two units similar to that shown in Fig. 8 coupled to form a single transmission.

One principle of the invention as applied to its high-speed condition is diagrammatso ically illustrated in Fig. 1 wherein (2 indicates a shaft journalled in fixed bearings b, b. A pulley 0, secured to shafta, has wound thereon a flexible connection (2 having attached to its free end a weight e representing the power applied to the system. Also secured to shaft a is an arm f which engages (in the manner shown) an arm 9 secured to one end of shaft h journaled in a rotary member 2' loosely mounted on shaft (1 and constituting an equalizer or differential element. Secured to the other end of shaft k is an arm 7' having a lug 7a which extends into a-notch Z formed in the rotary member 2'. This construction permits a movement of arm 9' relative to the member 1', said arm being normally held in engagement with an arm n, hereinafter described, by a coiled spring we one end of which is attached to the member 71 and the other end of which is secured to the hub of the arm j. The arm 1 0 j eng es (in the manner shown) the arm n which is loosely mounted on the shaft a, said arm n being locked to a pulley 0 also loosely mounted 'on said shaft and preferabl of the same diameter as pulley c. A 'flexi le connection p is wound around pulley o in the op posite direction of the winding on pulley c, said connection having its free end attached to one end of a coiled spring 9 (representing the resistance) the other end of which is fixed. The minimum tension of the spring is to be considered sufiicient to overcome the inertia of the member 21 if permitted to act independently thereon.

Assuming the weight e (which constitutes the drive) to be exerting a pull in excess of the resistance offered by the spring q, the pulley a will be rotated in the direction of the arrow thereon, causing shaft a and arm 7 to rotate in the same direction and impart the effort to arm g due to the relation existing between the member 73 and the spring q as stated above, the arm 9 tends to and does revolve the shaft h, and therefore the member 2', bodily about the shaft a as an axis. This action causes the arm j to be revolved bodily about the same axis which in turn rotates the arm n on the shaft a. The movement of the arm n, through the pulley 0 and connection p, thus overcomes the resistance of the spring g. Since spring .9 offers less resistance at this time'than the pull of weight 6, the arms and 9 remain in engagement, as do also the arms 7' and 'n, and the whole mechanism revolves as a unit at the same speed and in the same direction as the drive. This action continues until the tension of the spring 9 becomes equal to the force of the drive, after which the forces become unbalanced, and the continued operation causes arm 9' to be turned through a partial rotation in the same direction as the drive about the axis of the shaft h. This partial rotation of arm is transmitted through shaft 7:, to army which causes said arm to be angularly advanced relative to the arm 7, the action taking place about the point of contact between these parts as a fulcrum. This causes the member 2' to ro tate momentarily at a faster rate of speed than the drive which condition has been brought about by the drive assisted by the interaction of the parts as above described. This action interrupts the driving engagement between the arm j and the arm n, at which time the recoil of spring g rotates pulley 0 and arm n in the opposite direction to the drive. Furthermore, after the interruption of the driving engagement between the arms j and 'n, the spring m causes arms'j and g to return to their normal positions, their movement in this direction being limited by the end of the notch Z. Arm y again resumes its driving engagement with arm n, and, since the tension of spring 9 has been decreased in the interim, the whole mechanism speed. It must be understood that this part of the mechanism only functions in the operation of the device when the high-speed portion ceases to function. In this figure, the shaft a has secured thereto a friction wheel 7' which engages a friction wheel 8 secured to one end of a shaft'tjournaled in rotary member 2' which is loosely mounted on shaft a. Attached to the other end of shaft t is a friction wheel M which engages a friction wheel '2) loose on shaft a. Locked to friction wheel 4), and loosely mounted on shaft a, is wheel 20 which receives the resistance to the drive. Friction wheels 1' and s are preferably of the same diameter while friction wheel at is of a greater diameter than friction wheel 0.

The mechanism shown in this diagram is for the purpose of permitting a description which will afford a clearer understanding of the lower range of speeds and bring out more clearly a so-called slipping clutch o eration of the device. In the operation 0 this portion of the device it must be understood that the resistance to the drive is greater than the driving efi'ort. Under these conditions the member z' is rotating faster than the drive as was explained with reference to Fig. 1. Friction wheel 7', which is rotated by the drive in a counterclockwise direction as viewed from the left, tends to drive friction wheel 8 in a clockwise direction, and friction wheel 8 through shaft .15 tends to drive friction wheel at in a clockwise direction as indicated by the dotted arrows on said wheels. Friction wheel u tends to drive friction wheel '0 in a counterclockwise direction, as indicated by ,the full-line arrow thereon. The resistance to the drive transmitted through the friction wheel v tends to prevent the friction wheels u and 8 from rotating in a clockwise direction indicated by the dotted arrows thereon.

We may assume the resistance in the wheel 0 to be great enough to hold it stationary, and the wheel 1' to rotate. As wheel '0 is of less diameter than wheel u, the tendency will be for member a to revolve in the same direction as wheel 1'. The result is that the friction wheels 8 and u together with the member 2' revolve bodily in a counter-clockwise .directionabout the shaft 0., as indicated b the arrow on member i. Due to the resigting action of friction wheel u over friction wheel 'v is similar to that ofa slipping clutch.

It is obvious that as the speed of friction wheel 2) decreases, the speed of member 2' increases and, as was previously stated whenthis part of the mechanism is functioning, member '1' rotates faster than the drive, and as the resistance to the drive slows down the follower or wheel o the differential in speed between member 2' and the drive increases.

In the ordinary transmission, when it is operating in the lower speeds, the force of the drive is increased by a smaller gear driving a larger one which transmits its force to the follower. This smaller gear driving a larger one gives the drive a greater leverage over the follower or in other words a mechanical advantage. But when the resistance to the drive is overcome by a slipping clutch, the force of the drive is not increased, but remains the same, and the follower is driven at a slower speed, at which speed the driving force is able to overcome such a resistance. The mechanism just described acts in a similar manner to a slipping clutch in that the force of the drive is not increased by a definite leverage, such as a small gear driving a larger one, but permits the force of the drive to drive the follower at a slower speed than the drive. I

The difference between the performance of a slipping clutch and the device herein described is that the slipping clutch delivers substantially the entire force of the drive to the follower, while with the present device not quite all the driving force is delivered, it being estimated that practically 95% of the driving force may be delivered to the follower, this being due to the necessity of designing this mechanism so that slower speeds may be had automatically. This difference of force is a sacrifice to secure the automatic relationand the following is a description of how this difference occurs:

It was previously stated that member 2' was rotating faster than the drive, but that friction wheel 7' was driving the mechanism. Since member 71 is rotating faster than friction wheel 9", and therefore friction wheel 8 is rotating on its axis in the opposite direction to that in which friction wheel 7 tends to drive it, the force of the drive is transmitted through friction wheel .9; shaft 25, rotary member 2' and friction wheel u to friction wheel a which receives the resistance to the drive. This force, at the periphery of wheel '0, is theoretically equal to the driving force at the periphery of wheel 1' times the radius of wheel '0 divided by the radius of wheel 7' (friction not considered).

For example let w=radius of wheel r :r'yradius of wheel '0 z=force of drive. Then the force of the drive applied against Y its resistance is But the diameter of wheel a; must be smaller radius of wheels 1 and s=g=x radius of wheel v=%= and the force of the drive against its resistance is or of the driving force; but this amount would be higher than 80% on account of the frictional resistance to the rotation of member z. o

It is obvious that the portion of the driving force (not considering friction) that acts on the resistance to the drive depends on the ratio of the diameter of the wheels 1 and o.

It is also obvious that the mechanism would not return of its own accord to the high speed condition until the resistance to the drive was substantially equal to that portion of the driving force transmitted to the member receiving the resistance. But once in the high speed condition the full driving effort (not considering friction) would be applied against the resistance to the drive. It is well known that this bringing of the mechanism to the high speed condition "could be accelerated in a moving automobile by momentarily closing the throttle and allowing the speed of the engine to become substantially the same as the propeller shaft of thevehicle, this being brought about by the momentum of the vehicle.

' The main feature of the operation of the portion of the device just described, is that the driving force transmitted by friction through member 11 and wheel shaft t and wheels wand '0, continually tends.

wheel 1' continually tends to drive wheel 8 in the o posite direction to which it is rotating an that this force is transmitted u and operates against the resistance. The driving force, tending to drive wheels u and s in an opposite direction to that in which they are revolving, causes wheel '0' to rotate part of the way with wheel 1', or at a lower speed than wheel 1', depending on how much greater the resistance is than the driving force.

In other words wheel 1', through wheel a,

to drive member 2' in the opposite direction to the drive; while the resistance, offered by wheel '0, through wheel u, shaft t and wheels 8 and r continually tends to drive the member i in the direction of the drive. Thus it is obvious that that part of the force of the drive that reaches the wheel '2: continually acts against the-resistance to the drive regardless of the difference in speed between member 1' and the drive. This is true when the low-speed condition exists.

Referring now to Figs. 3 to 7 inclusive, 11 denotes a driving shaft receiving power from an suitable source, said shaft being journa ed in bearings 12 and 12'. Bearing 12 is fixed, .while bearing 12' com rises the sleeve vof a member 13, which constitutes the driven member, and is adapted to deliver power to the mechanism to be driven, said member itself being journaled in a fixed bearing 14. Shaft 11 has secured thereto a ratchet 15 which is adapted to engage a pawl 16 (see Figs. 3 and 4). pivotally mounted on a disk ,17 which'encircles and is keyed to the hub of a gear 18 loosely mounted on the shaft 11. The pawl 16 is held-in engagement with the ratchet 15 by a spring 19. The pawl 16 and ratchet l5 constitute a simple form of one-way driving connection or over-running clutch of which any other suitable and wellknown form may be used. Gear 18 meshes with a gear 20 secured to one end of ashaft21 journaled in a rotary member 22, which is loosely mounted on shaft 11 and constitutes an equalizer or differential element. Secured to the other end of shaft 21 is a dog 23 which is adapted as shown to engage one of an annular series of pins 24 formin part of a wheel 25 (see Figs. 3 and 5) which is loosely mounted on shaft 11 but is locked to the sleeve 12 of the driven member 13 reviously referred to. The dog 23 is provi ed with a lug 26, on the inner face of the -hub thereof, which extends into a notch 10 formed in the rotary member 22 (see Figs. 3 and 6). This construction permits a movement of the dog 23 relative to the rotary member 22 for a purpose to be hereinafter described. Thedog 23 is normally held in engagement with one of the pins 24-by a coiled spring 27 one end of which is attached to the rotary member 22 and the other end of which is secured to mam the hub of said dog.

Gears

18 and 20 are preferably of the same pitch diameter, which diameter is referably equal'to the diameter of a cgiicle passing through the centers of the pins The mechanism so far described constitutes that portion of the device which transmits the highest speed to the driven member 13. The 0 rating principle was clearlyldescribed with reference to the diagram s own in Fig. 1. In actual operation with power in the rection of the arrow thereon, and the driven member 13 offering less resistance than the force of the drive, the ratchet 15 will be rotated in the direction of the arrow indicated thereon. Through awl 16 and d sk 17, gear 18 will be rotate in the same direction. Gear 18, through ear 20, will rotate member 22 in the same irection, and member 22 through dog 23 will rotate the applied to shaft 11 to rotate said shaft wheel 25 and consequently the driven member 13 in the same direction. above mentioned parts will be locked together and the entire mechanism will rotate as a unit with the drive, and there will be no relative movement of the arts.

When the high-speed condition exists, on account of the equal diameters of the effective portions of gear 18 and wheel 25, or in other words due to the equal leverages of

gears

18 and 20, dog 23 and wheel 25, the resistin force must be greater than the force 0 the drive before the dog 23 begins to be disengaged from-the wheel 25. Smce drivlng gear 18, through gear 20 and shaft 21, tends to drive member 22 in the opposite direction to the drive, and 'since the resistance of the wheel 25 is not greater than the force of the drive, the entire mechanism revolves as a unit and there is a balance of forces. But, as was previously stated, the leverages are equal, so that if the resisting force is greater than-the driving force, this resistance, through wheel 25, always tending to drive member 22 in the direction of the drive, now has its opportunity to actually accomplish this result by partially rotating the dog 23. We now have an unbalanced condition of the forces and the high-speed portion of the'mechanism ceases to function.

The mechanism which transmits speeds lower than the high-speed to the driven member 13 will now be described. Secured to the shaft 11 is a gear 28 which meshes with a gear 29 secured by a pin and slot connection 30 to one end of a shaft'31 journaled in the rotary member 22 previously referred to at a point diametrically opposite the shaft 21 therein. Secured to the other end of shaft 31 is a gear 32 which meshes with a gear 33 loosely mounted on the driving shaft 11 but locked to the wheel 25 as shown in Fig. 3.

Gears

28 and 29 are preferably of All of the the same pitch diameter while gear 32 is of a reater pitch diameter than gear 33.

n the operation of this portion of the device, the principle of which was clearly described with. reference to the diagram shown in Fig. 2, it must be understood, as was previously stated, that the resistance of the driven member 13 has reached a point where it is greater than the force of the drive. The operation of the device thereafter is as follows: Due to the resistange-of the driven member 13 and consequently of the wheel '25, the dog 23 is turned through a partial rotation in a. counterclockwise direction, as viewed in Fig. 5, which partially rotates shaft 21 and gear 20 in the same direction, thus causing the member 22 to rotate at a faster rate of speed than the drive. Dog 23 continues to rotate on its axis until it is released from the pin 2 1 with which it was engaged. The notch 10 is provided to limit the movement of dog 23, said notch being adapted to permit suflicient movement of the dog 23 to release it from engagement with the pins 24. After this action has taken place the pawl 16 passes over ratchet 15 and gears 18 and 20 have no relative movement. lVhile the. dog 23 is being disengaged, the gear 29, revolving bodily around the shaft 11 at a greater rate of speed than said shaft, has a rotative movement on the shaft 31.

Gears

32 and 33, due to their difference in ratio as compared to

gears

29 and 28, and depending on the amount of movement of gear 33, may or may not have driven shaft 31 as fast as gear 29 has rotated on said shaft. This possible movement of gear 29 relative to the shaft 31 has been permitted by the slot and pin connection 20 between said gear and said shaft. Gear 28 then takes up the drive and, due to the resistance of the driven member 13, which at this time exceeds the force of the drive, gears 29 and 32 and shaft 31 are revolved bodily about the axis of shaft 11, and consequently member 22 is rotated in a counterclockwise direction and at a rate of speed greater than the drive. Member 22 rotating faster than the drive carries gears 29 and 32 around gears 28 and 33 and imparts some movement to gear 33 in the direction of the drive. Gear 33, which is locked to the wheel 25, which in turn is locked to the driven member 13, imparts this movement to said driven member.

The mechanism above described is particularly adapted for use as a transmission in clockwise direction as viewed from the left of Fig.3. Shaft 11 drives ratchet 15 which through pawl 16 drives gear 18 in the same direction. Gear 18 rotates member 22 on shaft 11 in the same direction and due to the resistance of wheel 25, which is stationary due to the inertia of the vehicle, dog 23 starts to rotate on its axis and transmits this movement to gear 20, causing member 22 to rotate at a faster rate of speed than the drive.

This action continues until the dog 23 has been disen aged from the pin 24 of the wheel 25 with w ich it was engaged. After this has occurred gear 28 takes up the drive and, due to the resistance, which at this time exceeds the force of the drive gears 29 and 32 and sh ,ft 31 are revolved bodily about the shaft 11 causing member 22 to rotate in the same direction but at a greater rate of speed than the drive. Member 22, rotating faster than the drive, imparts some movement to gear 33 and, through wheel 25 and driven member 13, starts the car in motion. As the car moves along and the resistance decreases, the speed of the member 22 decreases and continues to decrease, with a corresponding increase in the speed of rotation of the driven member, until the resistance equals the force of the drive applied to gear 33 at which time the dog 23 is partially rotated to again engage the wheel 25, after which the mechanism revolves as a unit and the car is driven at high speed.

It will therefore be seen that the construction described provides a transmission which includes means, automatically controlled by the resistance of the driven element, for driv-. ing the latter at a speed which is substantially directly proportional to the speed of the driving element and the force exerted thereby and substantially inversely proportional to the resistance of the driven element.

The mechanism shown in Fig. 3 is preferably driven from the end described, but may be reversed and driven from the opposite end. In this case the member 22, in the low-speed condition, would rotate in the same direction but slower than the drive for some of the lower speeds, be stationary for one speed, and rotate in an opposite direction to the drive for the remainder of the lower speeds. From the performance of member 22 under these conditions, it is obvious that the mechanism would not return to the high-speed condition as quickly as if it was driven in the manner shown, in which case member 22 has to slow down to come into the high-speed condition, it being easier to'decelerate a 1'0- tatingbody than accelerate it.

In Fig. 8 is shown a modified construction in which a definite low speed may be attained. The high-speed portion of this device is similar to that shown in Fig. 3 with the exception of the addition of a gear 48 to be hereinafter described, and its parts have,

been designated by the same reference characters. The gear 48 is loosely mounted on the shaft 11 and is interposed between the wheel 25 and the driven member 13, being locked to each of said pa ts. The operation of this portion of the device is identical with that described in connection with the highspeed mechanism shown in Fig. 3. The lowspeed portion of this device is similar to that lar parts in Fig. 3. When the resistance to the drive has increased to a predetermined amount, the drive is through mechanism which will now be described. Secured to shaft 11, adjacent the bearing 12, is a gear 40 which meshes with a gear 41 secured to one end of a counter-shaft 42 which is journaled in fixed bearings 43. Secured to the other end of the counter-shaft 42 is a ratchet 44 (or equivalent one-way driving connection) which is engaged by a spring-pressed pawl 45 pivotally mounted on a gear 46 which is itself loosely mounted on said shaft and held in place thereon by a collar 47. The gear 46 meshes with the gear 48 above described. The pitch diameter of the gear 41 is preferably greater than that of the gear 40. with the result that the counter-shaft 42 is driven at a slower rate of speed than the drive.

The operation of the mechanism shown in Fig. 8 may be briefly stated as follows: When the force of the driving shaft 11 exceeds the resistance of the driven member 13, the drive will be through the high-speed portion of the mechanism in a similar manner to that described in reference to Fig. 3. At this time the gear 48 will be rotating at the same 5 eed and in the same direction as the drive.

ue to the fact that the counter-shaft 42 is rotating at a slower rate of s eed than the drive and also to the ratio 0 the gears 48 and 46, the gear 46 will be rotated by the gear 48 at a greater rate of speed than might be imparted to it by the drive, and the gear 46 will, therefore, rotate idly on the shaft 42 with the pawl 45 passing freely over the ratchet 44. When the resistance of the driven member 13 has increased to a point just beyond the force of the driving shaft 11, the high-speed portion will be thrown out of operation as described with reference to Fig. 3 and the drive will be through the parts of the low-speed portion of the device which correspond to the low-speed portion shown in Fig. 3. At this time the gear 48 will still be rotating the gear 46 at a greater rate of speed than might be imparted-to it bythe drive and will continue to do so until the resistance of the driven member 13 has increased to a predetermined point, determined by the ratio of the gears 40 and 41 and the ratio of the gears 48 and 46. At this time, due to the ratio of the above described train of gears, the gear 46 will be driven by the shaft 11 through the gears 40, and 41 and the ratchet 44 and pawl 45 at a greater speed than the gear 48 tends to drive it. It will thus be seen that a definite low speed has been reached, the drive at this time being through shaft 11, gears 40 and 41, ratchet 44 and pawl 45, gears 46 and 48 and driven member 13.

The mechanism just described is particularly adapted for use as. a transmission in heavy passenger cars and small trucks.

Fig. 9 shows a transmission in which two "sets of mechanism as disclosed in Fig. 8 are joined together.

For convenience the set adjacent the source of power is designated as a whole by the reference character A, while the other set is designated by the reference character B.-

Similar parts are designated by the same reference characters used in Fig. 8, with the exception of the driving shafts which are designated 11 and 11', and the driven members which are designated 13 and 13' for set A and set B respectively. The driven member 13 of set A is secured to the gear 40 of set B for rotation with said gear and consequently with the shaft 11.

The operation of the complete device shown in Fig. 9 may be briefly stated as follows: When the resistance of the driven member 13' is less than the force of the driving shaft 11, the drive is through the high speed portions of sets A and B, the gear trains of both sets idling because the gears 48 will be rotating the gears 46 at a greater rate of speed than the gears 40 tend to rotate them. This constitutes the high-speed condition. When the resistance of the driven member 13' increases to a point sufliciently beyond the force of the drive, the drive is throu h the low-speed portion of one set and the high-speed portionof the other set, the gear trains of both sets not functioning at this time. When the resistance to the drive is increased to a redetermined point, the train of gears of tl iat set which was operating in low-speed takes up the drive. This condition constitutes a definite intermediate speed. If the resistance is sufliciently further increased, the set that was operating in highspeed now operates in low-speed exclusive of its gear train, and, with a further increase in resistance, said set operates through its gear train which results in a definite low-speed. It will thus be seen that, with two sets of mechanism joined together, three definite speeds may be attained. With three sets, four definite speeds may be attained, and so on. The above described mechanism is particularly adapted for use 'as a transmission in large trucks, buses and machines where a number of definite speeds are required.

I claim: 1. The combination of a driving element, a driven element, and a change-speed mechanism connecting said elements including an equalizing element, a shaft journalled in said last named element, operating connections be tween said driving element and said shaft, and operating connections, automatically controlled by the resistance of said driven element and including a releasable driving connection between said shaft and said driven element, whereby the latter may be driven when said resistance is not greater than the force exerted by said driving element.

- 2. The combination of a driving element, a driven element, and a change-speed mechanism connecting said elements including an equalizing element, a shaft journalled in said last named element, a one-way driving connection between said driving element and said shaft, a releasable driving connection, automatically controlled by the resistance of said driven element, between said shaft and driven element whereby the latter may be driven when its resistance is not greater than the force of said driving element and a second shaft journalled in said equalizing element and having operative connections with said driving element and said driven element whereby the latter may be driven when said releasable driving connection is released.

3. The combination of a driving element, a driven element, an equalizing element mounted to rotate about the axis of the driving element, a shaft journalled in said equalizing element, a dog fast on said shaft, a circular series of stops connected with said driven element and engaged by said dog, a gear fast on said shaft, a second gear loose on said driving element and meshing with said first-named gear, a one way driving connection between said driving element and said second gear, a second shaft journalled in said equalizing element, a third gear on said second shaft, a fourth gear meshing with said third gear and loose on said driving element but connected with said driven element for rotation therewith, a fifth gear having a limited rotary movement on said second shaft, and a sixth gear fast upon said driving element and meshing with said fifth gear.

4. The combination of a driving element, a driven element, an equalizing element mounted to rotate about the axis of the driving element, a shaft journalled in said equalizing element, a dog fast on said shaft, a circular series of stops connected with said driven element and engaged by said dog, a gear fast on said shaft, a second gear loose on said driving element and meshing with said first-named gear, a one way driving connection between said driving element and said second gear, a second shaft journalled in said equalizing element, a third gear on said second shaft, a fourth gear relatively smaller than said third gear and meshing therewith, said fourth gear being loose on said driving element but connected with said driven element for rotation therewith, a fifth gear having a limited rotary movement on said second shaft, and a sixth gear fast upon said driving element and meshing with said fifth gear.

5. The combination of a driving element, a driven element, change-speed gearing connecting said elements and including means controlled by the resistance of said driven element when said resistance is less than a predetermined limit, for driving the said driven element at a speed substantially inversely proportional to said resistance, and additional means for automatically driving said driven element at a constant speed when said resistance is greater than saidlimit, said lastnamed means comprising a countershaft and intermeshing gears connecting said countershaft with said driving and driven elements, there being a one-way driving connection between one of said gears and the part by which it is carried.

6. The combination of a driving element, a driven element, and change speed mechanism for connecting said elements for driving the driven element at a constant high speed ratio, at a constant low speed ratio, and at intermediate speed ratios, said mechanism includingatorquebalancing powertransmitting member movable with said driving and driven elements and also relative thereto at variable speed, said mechanism also including means controlled by the torque ratio of said elements and connecting said torque balancing member therewith for controlling the relative speed of said elements and member in accordance with said ratio.

7. The combination of a driving element, a driven element, and change speed mechanism for connecting said elements for driving the driven element at different speed ratios with respect to the driving element, said mechanism comprising means for driving said driven element at a constant intermediate speed ratio including a countershaft, intermeshing gears connecting said countershaft with said driving element, and other in termeshin g gears constituting, at least in part,

the driving connection between said countershaft and the driven element, there being a one-way driving connection between one of said gears and the member by which it is carried. i

8. The combination of a driving element,

a driven element, and change speed mecha nism for connecting said elements for driving the driven element at different speed ratios with respect to the driving element, said mechanism comprising means for driving said driven element at a constant low speed ratio including a countershaft, internism connecting said elements and including,

means for driving saiddriven element indirectly from said driving element, said means including, in combination, a torque balancing power transmitting member movable continuously relatively to the said driving and driven elements when said elements are indirectly connected, and means controlledby the torque ratio of said elements and con nect-ing said torque balancing member therewith for controlling the relative speed of said elements and member in accordance with said ratio. A

10. The combination of a drivin element, a coaxial driven element, a torqueialancing power transmitting member mounted to rotate about the common axis of the driving and driven elements and movable with said elements and relatively thereto at variable speed, and transmission elements carried by said torque balancing member and connecting said driving and driven elements, said torque balancing member moving continuously relatively to said driving and driven elements when said driving and driven elements are indirectly connected by said transmission elements.

11. The combination of a driving element, a driven element, means for driving said driven element at substantially the same speed as that of-said driving element, said means including a torque balancing power transmitting member-movable relatively to said driving and driven elements and controlled by the torque ratio thereof :for movement relative to said driving element, for disconnecting said driving means, and means cooperating with said member rendered operative when said driving means is disconnected for driving said driven element from said driving member at a reduced speed, said torque balancing member moving continuously relatively to said driving and driven elements after said speed reduction is established.

12. The combination of a driving element, a driven element, means for driving said driven elelnent at substantially the same speed as that of said driving element, said means including a torque balancing power transmitting member movable relatively to said driving and driven elements and controlled by the torque ratio thereof for movement relative to said driving element, for disconnecting said driving means, means cooperating with said members rendered opez-atlve when said driving means is disconnected for driving said driven element from 13. The combination of an initial driving element, a final driven element, and a plurality of change-speed mechanisms arranged in succession connecting said elements and each including in combination, a driving and drivenmember, means connecting said members for driving said driven member directly and indirectly from said driving member, said means including, in combination, a torque balancing power transmitting member movable continuously relatively to the said driving and driven members when said members are indirectly connected, and means controlled by the torque ratio of said driving and driven members and connecting said tor uebalancing member therewith for control ing the relative speed of said driving and driven members and said torque balancing member in accordance with said ratio.

14. The combination of an initial driving element, a final driven element, and a plurality of change-speed mechanisms arranged in succession connecting said elements and each including in combination, a driving and driven member, means connecting said members for driving said driven member directly and indirectly from said driving member, said means including, in combination, a torque balancing power transmitting member movable continuously relatively to the said driving and driven members when said members are indirectly connected, and means controlled by the torque ratio of said driving and driven members and connecting said torque balancin member therewith for controlling the relative speed of said driving and driven members and said torque balancing member in accordance with said ratio, and means to limit the speed reduction in each of said mechanisms.

15. The combination of a drivingelement, a driven element, and a change-speed mechanismconnecting said elements and including means for driving said driven element directly or indirectly from said driving element, said means including, in combination, a torque balancing power transmitting member movable with said driving and driven. elements when said elements are directly connected, said torque balancing member moving continuously relatively to said driving and driven elements when said elements are indirectly connected, and means controlled by the torque ratio'of said elements and connecting saidtorque balancing member therewith for controlling the relative speed of said elements and member in accordance with said ratio.

16. The combination of a driving element, a driven element, means for driving said driven element at substantially the same speed as that of said driving element inc uding a torque balancing power transmitting member movable relatively to said driving and driven elements and controlled by the torque ratio thereof for movement relative to said driving element for disconnecting said driving means, and means cooperating with said member rendered operative when said driving means is disconnected for driving said driven element from said driving element at a reduced speed, said torque balancing member moving continuously relatively to said driven element after said speed reduction is established.

17'. The combination of an initial driving element, a final driven element, and a plurality of change-speed mechanisms arranged in succession connecting said elements and each including, in combination, a driving and driven member, means for driving said driven member at substantially the same speed as that of said driving member including a torque balancing power transmitting member movable relatively to said driving and driven members and controlled by the torque ratio thereof for movement relative to said driving member for disconnecting said driving means, and means cooperating with said member rendered operative when said driving means is disconnected for driving said driven member from said driving member at a reduced speed, said torque balancing member moving continuously relatively to said riving and driven members after said speed reduction is established.

18. The combination of an initial driving element, a final driven element, and a plurality of change-speed mechanisms arranged in succession connecting said elements and each including, in combination, a driving and driven member, means for driving said driven member at substantially the same speed as that of said driving member, including a torque balancing power transmitting member movable relatively to said driving and driven members and controlled by the torque ratio thereof for movement relative to said driving member for disconnecting said driving means, and means cooperating with said member rendered operative when said driving means is disconnected for driving said driven member from said driving member at a reduced speed, said torque balancing member moving continuously relatively to said driven member after said speed reduction is established.

19. The combination of a driving element, a driven element, a rotatable torque receiving member, means for providing a driving connection between said member and said elements adapted to transmit opposed forces to said member, one of said forces acting to disconnect said driving connection and including a force responsive to the torque of said driven element, the other of said forces acting to maintain said driving connection and including a force responsive to the torque of said driving element, whereby said member is rotated to disconnect said driving connection in response to the resultant force created when said force including that responsive to the torque of the driven element exceeds the other of said opposed forces.

20. The combination of a driving element, a driven element, means for providing driving connections between said, elements to drive said driven element at different speed,

ratios with respect to said driving element, one of said driving connections including a rotatable torque receiving member and means for providing a driving connection between said member and said elements, said last mentioned means being adapted to transmit opposed forces to said member, one of said forces acting to disconnect said driving connection and including a force responsive to the torque of said driven element, the other of said forces acting to maintain said driving connection and including a force responsive to the torque of said driving element, whereby said member is rotated to disconnect said driving connection in response to the resultant force created when said force including that responsive to the torque of the driven element exceeds the other of said opposed forces.

21. The combination of a driving element, a driven element, means for providing driving connections between said elements to drive said driven element at difl'erent speed ratios with respect to said driving element, one of said driving connections including a rotatable torque receiving member and means for providing a driving connection between said member and said elements, said last mentioned means being adapted to'transmit opposed forces to said member, one of said forces acting to disconnect said driving connection and including a force responsive to the torque of said driven element, the other of said forces acting to maintain said driving connection and including a force responsive to the torque of said driving element, whereby said member is rotated to disconnect said driving connection in response to the resultant force created when said force including that responsive to the torque of the driven element exceeds the other of said opposed forces, another of said driving connections operating independently of said torque receiving member.

22. The combination of a driving element, a driven element, means providing driving connections between said elements to drive said driven element at different speed ratios with respect to said driving element, at least two of said driving connections each including a separate rotatable torque receiving member.and separate means for providing a driving connectlon between the same and said elements each of said last mentioned means being adapted to transmit opposed forces to one of said members, one of said forces acting to disconnect said driving connection and ineluding a force responsive to the torque of said driven element, the other of said forces actin to maintain said driving connection and including a force responsive to the torque of said driving element, whereby said 1 member is rotated to disconnect said driving connection in response to the resultant force created when sald force including that responsive to the torque of the driven element exceeds the other of said opposed forces.

23. The combination of a driving element,

a driven element a rotatable torque receiving member, means for providing a driving connection between said member and said elements adapted to transmit opposed forces to said member, one of said forces acting to disconnect said drivin-g connection and including a force responsive to the torque of said driven element, the other of said forces acting to maintain said driving connection and including a force responsive to the torque of said driving element, whereby said member is rotated to disconnect said driving connection in response to the resultant force created when said force including that responsive to the tor ue of the driven element exceeds the other 0 said opposed forces, said resultant force acting to rotate said member continuousl after said driving connection has been ren ered' inoperative.

. 40 In testimon whereofIaflix 111 Si ature.

ARROLL H. RI H RDS.