US2326670A - Sheave and pressure rider - Google Patents

Description

Aug. 10, 1943. 'J. c. PATTERSON, JR

SHEAVE AND PRESSURE RIDER Filed Aug. 21, 1941 2 Sheets-Sheet 1 Aug. 10, 1943.

J. c. PATTERSON, JR 2,326,670 SHEAVEE AND PRESSURE RIDER Filed Aug. 21, 1941' 2 Sheets-Sheet 2 3mm JJgwfifiallezwzgfi $2M lag/M I is carried between a sheave l I and a pressure roller l2, provided with a suitable means for application of pressure, such as the hydraulic cylinder 2|, illustrated in Figure l. 'I'hesheave l l comprises rigid flanges l 3 and a resilient body portion M of a synthetic rubber material maintained in place between the flanges by a plurality of clamping bolts IE. on a shaft [8 by conventional means'and the The flanges are mounted aseaevo cables of different cross sectional areas. Furthermore the size of the groove may be altered to compensate for wear by merely drawing flanges l3 together. This adjustment therefore renders installation less difficult and replacement less frequent.

Still greater advantages under certain drive conditions are obtained by using asystem such as that shown in Figure 6 wherein the cable is caused to lie in the groove l8 for a large portion of the periphery of the drive sheave I l by the use of a plurality of pressure riders I 2. It will be apparent that the increased contact area will prevent excessive wear of the resilient material by reducing the intensity of pressure as contrasted with the prior art expedient of maintain- I ing positive drive by the use of extremely high shaft 16 is provided with suitable driving means,

not shown. In the embodiment of Figures 2, 3 and 7 the inner faces ofthe flanges 13, are provided with recesses I! and the bolt l5 passes through a bore in the body Id of considerably greater diameter than the bolt.

By reference to Figure 3 it is seen also that the application of pressure to'the cable by means of pressure roller 12 causesthe resilient body [4 to be deformed, bulging outwardlyinto the recesses I! and also causin'gthe wallsof the, groove [8 to close 'in against the cable It thus providing a much greater area of contact between thecable and that portion of the sheave contacting therewith.

function. The importance of these recesses is their location: with respect to the material defining groove 18 which is suchas tocause the resilient material to bend around the cable as shown in Figure 3 when pressure is applied from the rider. Inasmuch as the ,material from which body portion M is composed-is deformable rather than compressible, it is evident that recesses ll' and Ila also function to-preventthe synthetic rubber material from being groundnut because of bearing against a hard surface. g

By means of the device discussed above, it is found that wear on the cableis greatly reduced by the coaction of two factors; v Because of the adjustable gripping action of driving contact between sheave and cable, it, is possible .to use drastically reduced pressures, Furthenthe' wear due to friction between the surfaceof a metal and a resilient substance is much less than the wear due to friction at a metal to-metal contact. Although I may use rubber or anyother resilient substance, I prefer touse the L'so-called synthetic substances because of their greaterresistance to deterioration in the presence of oils such as are used for lubrication and corrosion inhibition of the cable. Such syntheticcornpositi-ons as neoprene, Thiokof Formica and the like are found to be eminently satisfactory. 'I have also found that the use of the present device results in longer life of the cable because the' tendency to squeeze out the oils used for lubrication and corrosion inhibition is greatly reduced.

In the embodiment of the inventionshown in ripheral portion of the. sheave.

pressure.

In Figure 7 there is shown a modification of the embodiment illustrated in Figure 2.. A plurality of clampinglevers J9 are provided along thev two edges of theresilient body in the pe- Each of the clamping levers I9 is of a form similar to a bell'crank pivoted for rotation in aplane parallel to the axis of the sheave on the inner face of flange |3. One leg of each lever [5 lies between; flange l3 and resilient body 14 extending radially outward from the point of pivotal connection. The other leg is embedded in r the resilient body l4 extending into "that body By the use .of a resilient body l4 disposed 7 between rigid flanges I3 which may be drawn together by bolts I5 it'is evident that the initial diameter of groove I8 can be adjusted to receive and toward'the axis of the sheave. Upon application of pressure to the cable ID the cable tends to displace a portion of the resilient body I inwardly toward the axis of the sheave thereby acting upon the innerlegs of the levers l9. By reason of the pivotal connection of ithe levers to the flanges IS, the outer legs of the levers are caused to exert pressure against the resilient body toward thecable thus accentuating the efiectillustratedinFigure 3..

I have found that efficiency of the sheave may be enhanced by providing a tread in the cable carrying groove of the resilient body M. Figure- 8 illustratesa resilient body [4 having radial slots 20 extending from the surface of the groove l8 a substantial distance into the'body 14. Preferably the depth-of the slots 20"is'si1b V stantially equal to the depth to which the groove |8 wil1 be worn before replacement is advisable. It will be apparent to those skilled in the art that various modifications and adaptations of my invention may, be made without depart-.

ing from the spirit thereof. For example, it is often advisable to incorporate friction enhancingmaterials such as metal wire, fibre, hemp,

carbon, and other substances having suitable properties in the resilient body I4. It is to be understood-that the invention is not limited to the specific forms-illustrated and discussed, but

is limited only by --the scope of the appended claims.

What I claim is: I e

1 In the combination of asheave peripheral groove to receive a cable, rope-or belt, a rider cooperating with said groove and pressure means to apply pressure to said rider; a sheave comprising rigid circular flanges form ing sides of the sheave and each having its inner face recessed throughouta portion'thereof intermediate the axis and the periphery of the sheave and a resilient body portion having a peripheral groove lying between said flanges and normally ocupying the space between said flanges having a with the exception of the space in said recessed portions. 7

2. A device as defined in claim 1 having a plurality 'of clamping levers pivotally attached to the inner faces of said flanges outwardly of said recessed portions, one leg of each of said levers extending radially outward between said resilient body and said fiange and the other leg thereof extending at an acute angle to the face of said flange into said body and toward the axis of the sheave.

3. In the combination of a sheave having a peripheral groove to receive a cable or the like, a rider co-operating with said groove and means to apply pressure to said rider, a sheave comprising rigid flanges forming the sides thereof, a resilient body portion having a peripheral groove, said body portion lying between said flanges and being normally in contact therewith except in annular zones, each of which is defined,

the radial depth of the body portion being at least twice the diameter of the groove, and means passing through said Zones for drawing said flanges toward one another to reduce the diameter or said groove, whereby to render the sheave adaptable to use with cables of different diameters and to allow compensation for wear of the groove. 1

' i. A device as defined in claim 1 wherein said resilient body portion isprovided with a plurality of radial slots extending inwardly from the bottom of the peripheral groove to aiiord improved cable gripping qualities.

5; A device as defined in claim 3 wherein said resilient body portion is provided with a plurality of radial slots extending inwardly from I the bottom of the peripheral groove to afford gripping qualities.

improved cable 7 JOSEPH C. PATTERSON, JR.

at least in part, byan inner face of a flangei.

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