US1474752A - Speed-change mechanism - Google Patents

Description

Nov. 2 i923. M7435@ Y R. E. WINTERS S PEED CHANGE MECHAN ISM Filed April l5, 1921 2 Sheets-Sheet 1 Nov. 20 1923. BA1-74,752

R. E. wlNTERS S FEED CHANGE MECHANI SM Filed April l5, 1921 2 Sheets-Sheet 2 INVENTUR Patented Nov. 2), 1923.

rra iras ROBERT E. WINTERS, 0F CORAOPDLIS, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO ANTHONY C. DEAN, OF PITTSBURGH, PENNSYLVANIA.

SPEED-CHANGE MECHANISM.

Application filed .April 15, 1.921.

To all lwhom t may concern.'

Be it known that I, ROBERT E. VrNTERs, a citizen of the United States, and resident of Coraopolis, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in a Speed-Change Mechanism. of which the following is a specification.

This invention relates to a speed change mechanism and constitu-tes an improvement over the mechanism described and claimed lin my copending application Serial No. L63, 547, iiled April 22, 1921.

One object of the invention is to provide f means whereby power transmitted from an engine may be regulated to provide the desired speed and force without the use of gear shifts or the like.

A further object of the invention is to provide means whereby power transmitted from a running engine. may be suspended without the employment of any form of clutch mechanism.

A more specific object of the invention is to provide means whereby a member, the stroke of which is adjustable, is utilized to transform the movement of rotation of an engine shaft int-o regulable reciprocating movement, and means whereby this movement is again transformed into movement of rotation in a uniform direction.

Other objects of the invention are to provide means of this nature which are strong and compact, being thus well suited to installation in a power propelled vehicle and which comprise parts which are relatively few in number and which may be readily nurnufactnred and assembled.

In the accompanying drawings Figure 1 is a vertical section through the mechanism; Figure 2 is a horizontal section therethrough; Figure 3 is a rear elevation of the mechanism; Figure et is a front elevation of the reciprocating member of the mechanism and its associated parts; Figure 5 is a rear elevation of the portion of the mechanism illustrated in Figure 4; Figure 6 is a detail elevation of a portion of the means for producing movement of rotation in a uniform direction; Figure 7 is a cross sectional view on the line 7 7 Figure 5, illustrating particularly the reversing means of the mechanism; Figure 8 is a detail of one of the bearings for the reciprocating'mem- Serial No. 461,560.

ber; and Figure 9 is a detail view of a modified bearing.

In the drawings the reference numeral 1 designates a housing for containing the parts of the mechanism. R-otatably mounted in housing 1 is a wheel 2, between which and the housing are preferably interposed one or more anti-friction bands 3. theel 2 is rigidly secured, as by means of a small bracket et, with the engine shaft 5 to rotate therewith. A cross head or block 6 is slidable in a slot 7 in the wheel and carries a pin 8 for the transmission of power to the other portions of the mechanism.

rlhe pin S enters a slot 9 in alignment with the slot 7 in wheel 2,' this slot 9 being in a reciprocable member 10 slidably mounted transversely of housing 1. Reciprocating movement is imparted to member 10 by the action of pin S in the slot 9, the length of stroke of the reciprocating member depending obviously upon the eccentricity of the pin 8. Pin S is surrounded by a bushing 1l to completely fill the slot and prevent any torsional stresses upon the pin.

Pitman or slide 10 is slidable on tracks 12 in the housing 1, the housing being of suflicient width in this portion to permit of a pitman stroke of the maximum desired length. Freely rotatable in bearings 1S in the end members 14 and 15 of slide 10, are a pair of worm racks 16 and 17 in vertical alignment with each other. Meshing with both of said racks is a worm gear 18 directly connected with the power shaft 19, so that reciprocating movement of the worm is converted into movement of rotation of the power shaft.

lith the structure so far described, however, the rotation'of the power shaft would be in alternately reversed directions. As it is necessary for most useful work, such as the transmission of motive power for an automobile, that the power shaft be rotated in a uniform direction; special means must be provided for securing this uniform direction of rotation.

These means comprise primarily plates 2O and 21 of the general form of a bell crank lever and rotatably mounted one on each of the outer surfaces of the end members 14 and 15 of slide 10. The inner faces of the plates 2O and 21 are contacted by the points of cones 22 on the ends of the worm racks 16 and 17. In the moditication illustrated in Figure 9 The racks 16 and 17 are slidable in their bearings and each is provided with a pair of enlarged shoulders 2-1 and 25 arranged to contact or be freed from contact with the inner surfaces of end members lll and 15 according to the position of the rack. The cam surfaces on the arms of the plates 20 and 21 are oppositely inclined on each plate, so that they are disposed oppositely with reference to the similar ends of the two racks; and are also mounted in staggered relation so that they are also oppositely disposed with relation to the opposite ends of each of the racks.

IVhen, therefore, plate 2O is in such position that it bears against the adjacent point 23 to force rack 16 to the right (see Figure 4L of the drawings), shoulder 24C of this rack is forced out of contact with side frame 14- and shoulder 25 is forced into contact with side frame 15. The left hand end of the rack thus has a bearing on the point of cone 22, while the right hand end has a bearing at points much further from the central longitudinal axis o-f the rack.

In this position shoulder 25 of rack 17 is freed from conta-ct with side frame 15, having its bearing only by t-he contact of the cone with plate 2,1; while shoulder' 2st of this rack is forced into contact with side frame 14 of the slide.

The result of this arrangement is to cause an effect similar to that which would be obtained if worms having teeth of a different pitch could possibly be caused to mesh with a single worin gear having different portions provided with teeth for meshing with each of the worms. In such case, however, the construction would, of itself, prevent any rotation whatsoever.

lVith the struc-ture of the present invention, one rack acts upon the worin gear to cause rotation thereof while the other is free -to rotate idly. The racks thus alternate as fixed and free during alternate pitman strokes, and thus produce rotation of the worm gear and power shaft in a uniform direction.

Taking for example the position of the parts shown in Figure 4 of the drawings, as: the slide 10 moves from right to left the rack 16 will act to rotate the worm gear 18 while the rack 17 will be rot-ated idly. On the return stroke from left to right the rack 17 will act upon the worm gear while the rack 16 will be. rotated idly. The power shaft 1-9. will thus be rotated inA a uniform direction. Although, due to the alteration shaft in a uniform direction, lies in the al- Y ternation of the bearing points of the racks with relation to their central longitudinal axes. Thus with the parts in the position described above,rack 16 has the-bearing adjacent its right hand end removed a considerable distance from its central longitudinal axis; while the bearing at its left hand end, being a centrally disposed point, is practically on the central longitudinal axis 0f the rack. The efl'ect of this is to give the rack 16 an eccentric bearing point outwardly of its central longitudinal axis during movement of the slide from right to left, so that it is held against rotation and capable of imparting movement to the worm gear 18. Similarly the rack 17 has the bearing adjacent its left hand end removed from the central longitudinal axis of the rack; and this rack, therefore, is held to impart movement to the worm gear during movement of the slide from left to right.

It will be seen from the above, that it is the position of the bearing points with relation to the central longitudinal axis of the rack, and not the area of the shoulders, that is of importance. Thus instead of the shoulders shown, any desirable form of member may be placed on the rack in position to contactl the side frames at a point, or points, relatively far removed from the central longitudinal axis of the rack and from the point of contact of the cone or hall used.

lVith the relative dimensions of the parts shown, the lead of thescrew threads of the racks is approximate-ly 15 degrees. If the length of the racks, or the pitch of their threads be increasedY the outer bearing point must be removed' a corresponding distance further from the pitch line of the rack. This variation may be made within certain limits, but it will be understood that increase in the lead of the threads and remoteness of the outer bearing points cannot be continued indefinitely without impairing or destroying the function of the device.

Means are providedv for causing a reversal in the direction of rotation of t-he power shaft. by causing a reversal of the action of the racks. For this purposethe shaft 26 to which the plates 2O and 21 are secured is providedl with a longitudinal slot 27. In this slot engages the shoulder 28 of power shaft 19 inwardly of worm gear 18'. The power shaft 19 is slid'able in the hub 29 of the worm gear, and shoulder 28 engages in lli sil)

the not-ch 27 of shaft 26 in such manner that the shaft is freely slidable thereon. Engaging power shaft 19 by means of a collar 30 is an operating lever 31. By actuation Vof this reversing lever 31 the position of the plates 2O and 21 may be so shifted as to reverse the position of the cam surfaces and thus cause a reversal in the direction of rotation of worm gear 18 and power shaft 19.

In this reversed position plate 21 bears against the right hand cone of rack 16 to force the rack to the left, thereby freeing its shoulder from frame and bringing its shoulder 52st into engagement with frame 1l. Sin'iilarly plate 2O bears against the left hand cone of rack 17 to free its shoulder 21 from frame portion 1st and bring its shoulder into contact with frame por tion 15. The left hand end of rack 16 thus has bearing on its cone only against plate Q0, and the right hand end of rack 17 has bearing on its cone only against the cam surface of plate 21.

In the position described immediately above; as the slide 1() moves from right to left, rack 16 will be rotated idly while rack 17 will actY upon worm. gear 18 to rotate the same. Similarly as the slide moves from left to right, rack 16 will act to rotate worin gear 18 while rack 17 will be rotated idly.

Figure 1 of the drawings, which shows the mechanism as arranged for use in a power propelled vehicle, illustrates special operating connections for the reversing lever 31. As shown, the lever 31 is provided with curved extensions or horns 32 and 33. The extension 32 is hinged at 34 to the exterior of housing 1 while extension 33 connects with a rod 35 terminating in operating pedal 36. A coiled spring 37 lying` in a cup 38 formed exteriorly of housing 1, and hearing against lever 31 serves to maintain the lever normally in its released position.

When applied to a power propelled vehicle, the mechanism serves as a brake as well as a speed change mechanism. The braking action is secured by operating lever 31 to change the position of plates 20 and 21 without changing their position suiiiciently to cause a reversal in the direction of rotation of worm gear 18. The effect of this is to decrease the factitious difference in the lead of the threads upon the racks 16 and 17, and thus retard the rotation of power shaft 19.

Figures 1 and 2 of the drawings also show special automatic speed governing means for the device. These means are of particular advantage when the device is apsplied to a power propelled vehicle, and are specially claimed in eopending application, Serial No. 463,547, tiled April 22,1921.

The automatic speed governing means comprise a vane 39 carried by a collar 49 slidable on the engine shaft 5. Collar 40 embraces a radius rod 0r curved tongue 1l. which lies in a notch 42 in the engine shaft and is secured at its inner extremity to the cross head 6. As the interior of the housing is to be iilled normally with a liquid lubricant, the frictional engagement of collar 40 on the engine shaft and the resistance of the liquid will cause the vane 39 to creep outwardly on the shaft with an increase in engine speed. This action depresses the forward portion of radius rod 41 and raises its rearward extremity, connected with cross head 6, so that the pin 8 is moved from the centers of slots 7 and 9 a distance corresponding to the increase in engine speed. This in turn increases the length of stroke of pin 8 and of slide 10. As the speed of rotation of wheel 2 remains unaffected b v this adjustment, the speed of movement ol slide 10 is increased with increase in the. length of its stroke. The pull is of course correspondingly decreased.

lVith decreased engine speed, the collar 40 may be drawn inwardly by means of a spring against the resistance of which the vane 39 moves outwardly. This inward movement of collar serves to depress the inner extremity of radius rod 41, thus moving cross head 6 toward the center' of slot 7 and the pin 8 toward the centers of slots 7 and 9. The speed of movement of slide 10 and worm gear 18 is thus decreased but the pull increased.

Thus if the mechanism be applied to a power propelled vehicle; the slowing of engine speed when the vehicle is on an upgrade will automatically cause the pull for taking the grade to be increased. Upon speeding up of the engine when the summit of the hill has been reached, the creeping of vane 39 will cause the speed of rotation of the power shaft to be increased,

This arrangement automatically reduces the speed of rotation of the power shaft only the amount necessary to secure the pull requisite under the existing grade, condition'of the roadway, etc. This is possible because 'there are no fixed steps, as with a gear assembly, but on the contrary all changes are gradual and without noticeable graduation. This fact, in itself, avoids shocks and jars to the entire structure of the car.

It will also be understood that when the pitman pin 8 is in the exact center of the slots 7 and 9, the eHect will be the same as that obtained with the neutral of the ordinary clutch. That is, the engine will run free of the load as the pin 8 will merely rotate in the slots without exerting any force upon the slide 10.

)is illustrated, means are provided for bringing the mechanism into neutral and for controlling the speed at the will of the operator, these n'ieans being so arranged lll) as to normally interfere in no way with the automatic speed regulation. To give this independent control a yoke 43 carried by a lever 44 is secured to a rino' 45 set in collar 40. This lever has a. rota-table connection in the housing l and is also hinged to a linlr 46.

lll

Link 46 is in turn joined to an operating rod 47 which carries a pedal 48. To the extremit y of link 46 is secured coiled spring 49 which normally resists outward movement of vane 39 and collar 40. Depression of pedal 48 causes inward movement of collar to decrease the speed transmission or to place the operating pin 8 in neutral position; while release of the pedal permits governing vane 39 to exercise its normal effect.

The mechanism as a whole is simple and compact. rlhere are, moreover, no parts which are subjected to great stresses, and none, except the bushing surrounding the operating pin, which are subjected to great friction.

It will be understood further that the structure described above may not only be utilized in a speed change mechanism, but

may also be utilized in any mechanism for converting reciprocating motion into motion of rotation.

As the device is susceptible of a number of modifications, both as to form and arrangement, without departing from the spirit of the invention; the scope of the invention is to be restricted only by the limitations con tained in the claims appended hereto.

What I claim is:

l. In speed change mechanism a reciprocable slide having racks thereon, a power shaft, means on said power shaft engaging with said racks, means for causing said racks to act alternately during movement of the slide in opposite directions to revolve said power shaft in a. uniform direction, and means for reversing the action of said racks to reverse the direction of rotation of said power shaft,

2. In speed change mechanism ay reciprocable slide, a. power shaft, a gear on said power shaft. racks revolubly mounted in said slide and meshing with said `gear` means for holding and releasing each of said racks alternately during movement of said slide in opposite directions, and means for reversing the action of said racks.

3. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, a power shaft, a gear on said power shaft, racks revolubly mounted in said slide and meshing with said gear7 contact members on one end of each of said racks adjacent the longitudinal axis of the rack, and contact members removed from the longitudinal axis of 'the racks on the opposite ends thereof; said contacts being relatively staggered in the slide.

4. In mechanism for converting reciproeating mot-ion into motion of rot-ation, a reciprocable slide, a power shaft, a gear on said power shaft, racks revolubly mounted in said slide and meshing with said gear, Contact members; on one end of each of said racks adjacent the longitudinal axle of the raclr, contact members removed from the longitudinal axis of the racks on the opposite ends thereof, said contacts'being relatively staggered in the slide, and means for reversing the posit-ion of said contact members.

5. In mechanism for converting reciproeating motion into motion of rotation, a re-' ciprocable slide, and revoluble racks in said slide, each of said racks bearing at one end thereof upon a point adjacent the longitudinal axis of the rack and at the other end thereof on a point removed from the longitudinal axis of the rack.

(5. In mechanism for converting reciprocating motion into motion of rotation, a re ciprocable slide, revoluble racks in said slide having at each end thereof a contact point adjacent the longitudinal avis of the rack and a member arranged to Contact the slide outwardly of said longitudinal axis, and members arranged to provide a bea-ring snr- :lace for the inner contact point at one end of each rack and to free the outwardly disposed contact member alt that end of the rack from contact with the slide.

7. In mechanism for converting reciprocating motion into motion of rotation, a power shaft, a gear on said power shaft, a rcciprocable slide, racks revolubly mounted in said slide and meshing with said gear, contact members on one end of each of said racks .adjacent the longitudinal axis of the rack, contact members removed from the longitudinal axis of the racks on the opposite ends thereof, movable members for maintaining said contacts in relatively .staggered position in said slide, an operating shaft for said movable members, and means slidably engaging said shaft and arranged to shift the position of said movable members to reverse the position of said contacts. Y

S. In speed change mechanism a reciprocablc slide,` a power shaft, a gear on said power shaft, 'racks -revolubly mounted in said slide and meshing with said gear, means comprising beveled members movable in said slide for holding and releasing each of said racks alternately during movement of said slide in opposite directions, an op erating shaft for said plates and means slidably engaging said shaft and arranged to shift the position of said members to reverse the action of said racks.

9. In speed change mechanism a reciprocable slide having racks thereon, a power shaft, means on said power shaft engaging with said racks, means comprising beveled members movable in said slide for causing said racks to act alternately during movement of the slide in opposite directions to revolve said poiver shaft -in a uniform direction, an operating shaft for said plates, and means slidably engaging said shaft and arranged to shift the position of said movable members to reverse the action of said racks.

10. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, a power shaft, a gear on said power shaft, racks revolubly mounted in said slide and meshing with said gear, contact members on one end of each of said racks adjacent the longitudinal axis of the rack, Contact members removed from the longitudinal axis of the racks on the opposite ends thereof, said contacts being relatively staggered in the slide, beveled members movable in said slide and arranged to bring oppositcly disposed contact members on said racks into Contact with the slide. an operating shaft for said movable members, and means slidably engaging said shaft and arranged to shift the position of said movable members to reverse the position of said contacts.

11. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, and revoluble spiral racks in said slide, each of said racks having bearing at both ends thereof in said slide, the bearing surfaces of each rack at the opposite ends thereof being at different distances radially from the longitudinal axis of the slide, the bearings on both racks being relatively staggered in the slide.

12. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, and revoluble spiral racks in said slide; each of said racks havin@ at both ends thereof two bearings dispose at different radial distances from the longitudinal axis of the rack, an inner bearing on one end of each rack and a radially outer bearing on the other end thereof being s1- multaneously effective and the effective bearings on both racks being relatively staggered in the slide.

13. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, revoluble spiral racks in said slide; each of said racks having at both ends thereof tivo bearings disposed at different radial distances from the longitudinal axis of the rack, an inner bearing on one end of each rack and a radially outer bea'fring on the other end thereof being simultaneously effective and the effective bearings on both racks being relatively staggered in the slide; and plates in said slide having beveled surfaces contacting said racks and arranged to reverse the effective bearing on both ends of each rack.

14. In mechanism for converting reciprocating motion into motion of rotation, a reciprocable slide, revoluble spiral racks in said slide; each of said racks having at both ends thereof tivo bearings disposed at different radial distances from the longitudinal axis of the rack, an inner bearing on one end of each rack and a radially outer bearing' on the other end thereof' being simultaneously effective and the effective bearings on both racks being relatively staggered in the slide; plates in the slide having beveled surfaces contacting said racks for reversing the effective bearing on both ends of each rack, and means for shifting the position of said plates to effect such reversal.

In Witness whereof, I hereunto'set my hand.

ROBERT E. WIN TERS. Witnesses:

E. M. DWYER, E. B. WAI/rens.

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