US923787A - Variable-drive mechanism. - Google Patents

Description

S. B. GRAY, DEGD.

B. S. GRAY, BXEOUTOB. VARIABLE DRIVE MECHANISM.

APPLICATION FILED APR. 6. 1906.

Patented June 1. 1909.

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Patented June 1. 1909.

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UNITED STATES PATENT OFFICE.

STEPHEN B. GRAY, OF JACKSONVILLE, ILLINOIS; BARTLETT S. GRAY EXEOUTOR or SAID STEPHEN B. GRAY, DEoEAsED.

VARIABLE-DRIVE MECHANISM.

Specification of Letters Patent.

Patented June 1, 1909.

To all whom it may concern:

Be it known that I, STEPHEN B. GRAY, a resident of Jacksonville, in the county of Morgan and State of Illinois, have invented certain new and useful Improvements in Variable-Drive Mechanism, of which the following is a full, clear, and exact description.

The invention relates to variable drivemechanism and designs more particularly to provide an improved construction of variable pulley, and improved mechanism for relatively adjusting the cooperating pulleys of a driving mechanism.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings: Figure 1 is a plan view of a variable drive-mechanism embodying the preferred form of the invention, a portion of the belt being broken away. Fig. 2 is a view in side elevation of the cams for shifting the adjusting levers, the cross-bars whereon they are supported being shown in section. Fig. 3 is a section on line 33 of Fig. 1. Fig. 4 is a side elevation, the supporting-frame being shown in section. Fig. 5 is a detail section on an enlarged scale, taken on line 5-5 of Fig. 6, some of the levers whereby the periphery-sections are supported being omitted. Fig. 6 is a view in vertical section of one of the pulleys. Fig. 7 is a central longitudinal Section on line 77 of Fig. 6.

The variable drive mechanism usually comprises a pair of pulleys which are respectively mounted on shafts from one of which motion is imparted to the other. These pulleys are of like construction and are provided with variable or adjustable rims. ley comprises abody or support which serves as a guide for the rim-sections and whereby the sections are connected together for revolution. The body or support is formed of sections 20 and 21secured togetherbybolts 23. One of the sections is provided with a hub 22 whereby it can be secured to its shaft. Each section of the body comprises a side 24 having radial slots 25 therein and an inwardly extending web or portion 26 and a central portion 27. The rim or drive-face of the pulley consists of a plurality of sections 28 having their ends held in slots 25 of the body, so the sections will revolve with said body. The rim-sections are adjustable to vary the size of the rims or working-face of the pulley the wheel-shaft.

The pul-.

and are supported in parallel relation by a pair of links 29 and 30, respectively pivoted near the ends of each section as at 31 and 32. Each of said links has its outer ends bifurcated to receive the rim-section to which it is pivoted and the links of a bar are slightly offset with relation to each other and crossed to provide a more compact construction. The inner end of each of the pulley-links extends through a slot 34 in web 26 of the body and is provided with a round terminal-36 whereby it is pivotally connected to a longitudinally movable adjusting-collar mounted on Each of said collars comprises an inner-member 37, having a V shaped groove 39 for each link-end 36 and a member 38 alsoprovided with a V shaped groove 41 for each link-end and in said grooves the link-ends are pivotally held in such manner that the ends will be moved longitudinally with the adjusting-collars to shift the adjusting- links 29 and 30, of the pulley positively and conjointly, inwardly and outwardly to vary the size of the rim. Member 38 is adjustably held by a follower 42, adjustably connected by a screw-thread to collar-member 37. Screws 44 secure the follower and member 38 in set relation. Collar-member 37 is caused to revolve with the wheel-shaft a, by a key 45, which, however, permits longitudinal adjustment of the collar to vary the size of the pulley. A trunnioncollar 47 mounted on follower 42, is provided with a face 48 of anti-friction metal, such as Babbitt, for engaging one side of follower 42 and pins 49 for engaging the other side of the follower, and trunnions 50, to which are connected the shifter-levers for operating the adjusting-collars to vary the size of the rim and for holding the collars in assigned position longitudinally.

In the operation of the pulley thus described, the rim-sections and supportinglinks are guided in the body and driven thereby, and by longitudinal shift of the adjustin -collars, all of the crossed links 29 and 30 wil be conjointly o erated to move the rim-sections radially independently or without shift of the wheel body and will holdthe sections to form a rim or working-face of the desired diameter for a belt.

Usually in variable drive-mechanism, two of the variable pulleys are operated together and the size of one pulley is increased and the other is correspondingly decreased, so the mechanism can be continuously operated without change of structure or variation of the belt. In Figs. 1 to 5 is illustrated a driveanechanism which comprises pulleys A and B of the construction hereinbefore described, and a belt C operatively connecting the pulleys so one will be driven from the other. Pulley A is mounted upon a shaft a, and pulley B is mounted upon a shaft 1). Both of said shafts are mounted in bearings secured to a frame D of any suitable construction. The bodies of each of the pulleys are secured against longitudinal movement and to revolve with their respective shafts. The shifting-mechanism for operating the adjusting-collars of wheel A comprises levers 51 and 52, each having a bifurcated end connected to trunnions 50 of one of the collars 47. Said collars are respectively fulcrumed at 57 and 58 in brackets 59 and 60, respectively secured to cross-bars 61 and 62. The shifting-mechanism for pulley B comprises levers 53 and 54, each of which is provided with a bifurcated end connected to the trunnions 50 of collars 47 for said wheel and is pivoted at 55 in a fixed bracket 56 secured to a supporting-bar 77 which is secured to the frame. The mechanism for adjusting the shifting-levers comprises a hand-wheel 63 which serves as a crank and is secured to a shaft 64 which is provided with a worm 65 engaging a worm-wheel 66, secured to a camshaft 67, journaled in a bracket 69, secured to supporting-bars 68. Cams 71 and 72 are secured to revolve with shaft 67 and each has cam-surfaces adapted to shift and control two of the shifterlevers. Cam 72 is provided with a cam-surface 73, adapted to shift lever 54 and a cam-surface 7 4 for shifting lever 51. Cam 71 is provided with a cam-surface 75 for shifting lever 52 and a cam-surface 76 for shifting lever 53. By adjustment of hand-wheel 63 the cam-shaft 67 can be revolved to simultaneously shift the shifter-levers for both pulleys so that the size of the rims of the pulleys will be respec tively increased and decreased. The wheelperipheries when correspondingly shifted, e. 9., to give the same aggregate diameter of the two pulleys, do not maintain tne belt and pulleys in driving relation because when the pulleys are of the same diameter the straight reach of the belt extends approximately from center to center of the pulleys and when the diameters of the peripheries are materially different the straight reach is less. In order to maintain proper frictional engagement at all times, despite variation of the diameter of the respective peripheries of the pulleys, earns 71 and 7 2 have their edges formed to differentially operate the shifter-levers so that proper frictional contact between the belt and the pulleys will be maintained. Assuming the mechanism to be in the position illustrated in Figs. 1 and 4, and it is desired to set the pulleys into position so the shafts will be driven at the same speed, the cams will differentially adjust the pulleys so that i l'thsegzite of the diameters of the two pulleys will be slightly greater than the aggregate of the diameters of the pulleys when these are in the position illustrated, to compensate for the differences aforesaid. These cams not only conjointly adjust the pulleys but also effect dill'erential adjustment so frietional engagement of the belt and the wheels will always be properly maintained. The radial shift of the rim sections is dill'crential with respect to the longitudinal shift of the collars, because a greater shift of the collars is necessary as the rim-sections approach their outward position, than when they are near their innermost position, and cams 71 and 72 are formed to rectify this dill'erence and to properly shift the collars so the resultant shift of the rim-sections will retain the peripheries and belt in operative relation.

A throw-off mechanism is provided whereby the belt and pulleys can be shifted into and out of operative relation. anism also makes it possible to adjust one of the pulleys to compensate for variation in belt length, resulting from stretching, wear or inaccurate fitting. The lever l'ulcra 57 and 58 of the shifting-levers of one of the shifting-mechanisms are movable to and from each other and are forced into position to keep the belt taut. Bars 62 and 61 to which the fulcrum-supporting brackets 5) and 60 are respectively secured by bolts are slidably mounted in brackets which are secured to the frame D. l lacl of the fulcrum-bars 61 and 62 has rigidly secured thereto a bracket 80 in which is held a plunger 81, which is pressed. outwardly by a. stout spring 82. A screw 83, adjusts the force of the spring to apply the desired force. A cam 84 journaled in brackets 85, is secured to a shaft 86, having a crank 87 whereby the shaft can be turned and a pawl and ratchet 88 for holding the shaft in assigned position. By adjustment of cam 84, greater or less pressure will be supplied to the fulcrum-lmrs to force the pivots of the shifting leyers into position and so the adjusted rinnsections of wheel A will take up any slack in the belt. By shift of cam 84 the diameter of pulley A can be varied so the belt will not be operated, and thus this mechanism can be. used as a throw-elf for pulleys It and B.

When it is desired to vary the speed of the driven shaft, the operator, by adjustment of hand-wheel 63 an simultaueously shift the adjusting-collars for both pulleys to which the supporting-levers are connected, so the. rim-sections will be shifted to effect desired variation of speed and to maintain proper relative diameters so the belt; will drive one pulley from the other. By o 'ieration ol' crank 87, cam 84- can be set. to compensate i This niechfor any slight variation in the length of the belt and can be used to disconnect and operatively connect the pulleys. It will be understood that one of the shafts, e. g., a, has power applied thereto in any well known manner and may be provided with a drivewheel 85 and that either shaft may be used to drive any machine or mechanism.

The invention possesses several important advantages. It provides a pulley in which the rim-sections are positively shifted inwardly and outwardly by the adjustingmechanism, and also mechanism which makes it possible to em loy a body secured to revolve with the sha't and against'longitudinal movement on the shaft. Furthermore, the sections and supports therefor are guided in the body and in such manner that a supplemental belt for securing the rimsections against outward movement is unnecessary. The invention also rovides improved mechanism for conjoint y adjusting a pair of pulleys and mechanism which effects proper shift of the sections to maintain the belt and the pulleys in operative relation. Furthermore, adjustment of the pulleys to start or stop the driven pulley, can be made without stopping the mechanism, an advantage which is very important in drivingmechanism for certain purposes, e. 9., in motor-vehicles.

The invention is not to be understood as restricted to the details of construction set forth, but may be varied without departing from the spirit and scope of the invention, and features of the invention may be employed severally without adoption in entirety, e. g., the improved pulley, and can be used to advantage in instances where a pair of variable ulleys is not necessary.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1.. In a variable pulley, the combination of a body having guides therein, rim-sections adjustably sustained thereby, and mechanism for adjusting the sections comprising a pair of links for each section extending through the guides in said body.

2. In a variable pulley, the combination of a body having guides therein, rim-sections adjustably sustained thereby, and mechanism for adjusting the sections comprising a pair of crossed links extending through the guides in said body.

3. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt and mechanism whereby the sections will be differentially adjusted comprising a pair of levers, each having a fixed fulcrum for one of the pulleys and a pair of levers each having an adjustable fulcrum for the other pulley.

4. In variable drive-mechanism the combination of a pair of pulleys, each comprising radially adjustable rim-sections, a belt, adjusting-mechanism for the sections comprising a cam for differentially adjusting the sections of one pulley with respect to those of the other, and means for shifting the cam.

5. In variable drive-mechanism, the combination of a pair of pulleys ,each comprising radially adjustable rim-sections, a belt, and mechanism for adjusting the sections comprising shifter-levers, a cam for shifting the levers, and means whereby the cam may be shifted.

6. In variable drive-mechanism, the combination of a pair of pulleys, each comprising radially adjustable rim-sections, a belt, and mechanism whereby the sections will be differentially adjusted comprising shifterlevers for each pulley, a cam, and means whereby the cam may be shifted.

7. In variable drive-mechanism, the combination of a pair of pulleys each com rising radially adjustable rim-sections, a be t connecting the pulleys and mechanism for adjusting the sections comprising a pair of cams whereby the sections of the pulleys will be difierentially adjusted with respect to one another and mechanism for conjointly shifting said cams.

8. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt, and mechanism for adjusting the sections comprising a pair of levers, each having a fixed fulcrum for one of the pulleys, and a pair of levers each hav- :ing an adjustable fulcrum for the other pul- 9. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt, and mechanism whereby the sections will be adjusted comprising a pair of levers each having a fixed fulcrum for one of the pulleys, a pair of levers each having an adjustable fulcrum for the other pulley, a cam, and means whereby the cam can be shifted.

10. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt, and mechanism for adjusting the sections, comprising a pair of levers, each having an adjustable fulcrum, spring pressed means whereby the levers will be forced into position to keep the belt taut, and adj usting-mechanism whereby the fulcra can be shifted.

1 1. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt connecting the pulleys, mechanism for adjusting the rimsections, and a cam whereby said mechanism ma be operated to release the belt.

12. n variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rim-sections, a belt, mechanism for adjusting the sections, comprising a pair of shifter-levers, each having a fixed fulcrum for one of the pulleys and a pair of levers each having an adjustable fulcrum for the other pulley, a cam for conjointly shifting said levers, and means for forcing the levers having adjustable fulcra into position to keep the belt taut.

13. In variable drive-mechanism, the combination of a pair of pulleys comprising adjustable rimsections, a belt, mechanism whereby the sections may be adjusted, com prising a pair of shifter-levers each having a fixed fulcrum for one of the pulleys and a pair of levers each having an adjustable fulcrum for the other pulley, a cam for conjointly shifting said levers, and spring pressed means for forcing the levers having adjustable fulcra, into position to keep the belt taut.

14. In Variable drive-mechanism, the combination of a pair of pulleys comprlsmg adjustable rim-sections, a belt, and mechanism for adjusting the sections, comprising a pair of shifter-levers, a supporting-bar for the fulcrum of each of said levers, and a yielding connection for forcing the fulcra into position. to keep the belt taut.

15. In variable drive-mechanism, the combination of a pair of pulleys con'iprising ad justable rim-sections, a belt, and mechanism for adjusting the sections, comprising a pair of shifter-levers, a sup mrtingdaar for the ful crum of each of the levers, and a yielding connection between the lovers, and means whereby the connection can be adjusted to shift the lever fulcra.

STEPHEN B. GRAY Witnesses J. WM. ELLsoN, C. A. Jonnson.

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