US2237394A - Oil well rig - Google Patents

Description

April 8, 1941 Y J. F. SMITH l 42.237394 i oIL WELL RIG f f Y Filed Feb. 27, V1939 *4 sheets-sheet` 1 Jama En Smith..

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ATTQQNRTS OIL WELL RIG I' VFiled Feb. 27. 19559 April 8, 1941.'

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W1 LMA .L F. SMITH 011.. WELL RIG Filed Feb. 27, l 1939 April s, 1941.

4 sheets-she@ 4 I Jamas F--5mth` ,l INvNTorg .BX u, MMM/@0% Y ATTORNLTS;

AND MECHANISMS Patented Apr. 8, 1941 Search Room OIL WELL RIG James F. Smith, Sandusky, Ohio, assignor to The Union Chain and Manufacturing .Company, Sandusky, Ohio, a. corporation of Ohio Application February 27, 1939, Serial No. 258,784

(Cl. i4-227) 18 Claims.

This invention relates more particularly to oil well rigs. In its most specific aspects the invention is particularly adapted for operating an oil well pump. In general, in such power transmission apparatus the load, imposed on the apparatus either due to the mode of operation of parts of the apparatus or due to the driven work device, or both, periodically iiuctuates or otherwise places more or less sudden strains on the apparatus, and this tends to and often results in injury to the apparatus, and particularly, injury to the speed reduction drive forming part of the apparatus. The invention has for its principal object the improvement of such power transmission apparatus.

The novel features of the invention will appear from this specification and the accompanying drawings showing several embodiments of the invention, and forming a part thereof, and all these novel features are intended to be pointed out in the claims.

In the drawings:

Figure 1 is a side elevation of an oil well rig embodying the invention,

Figure 2 is a vertical sectional view of a unit embodying speed reduction power transmitting apparatus, forming part of the rig shown in Figure 1, and showing said apparatus in side elevation,

Figure 3 is a section taken on the line 3-3 of Figure 2, looking in the direction of the arrows,

Figure 4 is a fragmentary side elevation, on a larger scale than Figure 2, of a portion of a .sprocket wheel forming part of the apparatus shown in Figure 2, certain parts being omitted for the sake of clearness,

Figure 5 is a section taken along the line of 5 5 of Figure 4, looking in the direction of the arrows,

Figure 6 is a fragmentary perspective view of a detail, on a scale larger than Figures 4 and 5,

Figure 7 is a perspective view of a detail, on the same scale as Figure 6,

Figure 8 is a fragmentary side elevation of another embodiment of a sprocket wheel, some of the parts of the fragmentary view being broken away,

Figure 9 is a section taken on the line 9-9 of Figure 8, looking in the direction of the arrows,

Figure 10 is a perspective view of a detail of the embodiment shown in Figures 8 and 9,

Figure l1 is a fragmentary side elevation of another embodiment of a sprocket wheel, and

Figure 12 is a section taken along the line |2|2 of Figure 11, looking in the direction of the arrows.

Referring to Figure 1 of the drawings, the embodiment here shown comprises any suitable form of prime mover 20, here shown as adapted to drive encased power transmitting apparatus 2| by means of a chain 22 cooperable with a sprocket wheel 23 associated with a shaft 24 of the power transmitting apparatus 2| and with a sprocket wheel 25 associated with the prime mover 20. Power is transmitted from the sprocket wheel 23 to a shaft 26 through speed reduction mechanism, as will appear hereinafter. As here shown, two cranks 21 are keyed to opposite ends of the shaft 26, one of the cranks being visible in side elevation in Figure 1. The cranks 2l are respectively pivotally connected to pitmans 28, in turn suitably connected to one end of a walking beam 29 pivotally mounted on a post 3U. The other end of the walking beam 29 is suitably connected to a work device such as a pump (not shown) in an oil well 3|. The connection to the pump or work device is here shown as a flexible cable 32 suitably connected to one end of the walking beam 29. One end of the shaft 24 is here shown as provided with a brake drum 33 with which is cooperable a brake band 34 actuatable by means of a brake rod 35 in any suitable or desired way.

Referring now to Figures 2 and 3, the driving shaft 24 is here shown as carried by and rotatable in ball bearings 36, carried by opposite Walls 31, 38 of a horizontally divided housing 39. The housing 39 comprises two principal parts fastened together by bolts 40, the joint between the housing parts defining the plane in which lie the axes of the shafts 24 and 26. II'he driving shaft 24 is adapted to transmit power to the driven shaft 26 by band means in driving relation to wheels mounted on the shafts 24, 26 respectively, and, as here shown, the wheels are sprocket wheels 4|, 42 with which a chain 43 cooperates. A suitable and desired speed reduction is of course attained by making the driving wheel 4| small and the driven wheel 42 large, but as far as certain features of the invention are concerned it is not essential that there be speed reduction.

The driving wheel 4| is here shown as keyed to the shaft 24.

The shaft 26 which carries the driven wheel 42 is carried by and rotatable in bearings l1, I8, in turn carried by and mounted in bearing supports extending laterally from the divided housing 39.

The housing 39 is preferably oil-tight and filled with oil or other suitable lubricant. An inspection opening is provided at the top of the housing 39, which may be closed by a cover H9, and this cover may carry an oil breather I 20.

ThHiven wheel 42 comprises as one principal part a spider 44 the hub 45 of which is keyed to the driven shaft 26, and, as the other principal part, a sprocket rim 46. The spider 44 is provided with a rim 41, the peripheral surface 48 of which is cylindrical as here shown, and the sprocket rim 46 is provided with a cylindrical surface 49, which, as here shown, ts the cylindrical surface 48 of the rim of the spider, but this t is such that the sprocket rim 46 may rotate relatively to the spider 44. While the sprocket rim 46 and the spider 44 are relatively rotatable, such relative rotative movement is limited, as will appear.

The sprocket rim 46 and the spider 44 are so connected to each other that when there is relative rotative movement of the sprocket rim and the spider away from a neutral position, energy will be stored tending to return the sprocket rim and the spider to the neutral position. This connection comprises a suitable and desired nurnber of cushion bushings 50 each provided with a pair of links 5| connected to the bushings 50 and also connected, in this instance, to the rim 41 of the spider (see also detail views, Figures 6 and '7).

Each cushion bushing 50 comprises a metallic generally cylindrical hollow core 52, preferably of steel, disposed within a metallic sleeve 53.,

Apreferably of steel, the core and the sleeve having interposed therebetween a tubular member 54 of resilient material. The member 5'4 of resilient material is preferably made of a moldable material. such as neoprene, for example, and is desirably molded to the core 52 and assembled in the sleeve 53 under high pressure. It will be evident that the resilient member may be made of any other suitable material. The ends of the core 52 project beyond the ends of the member 54 and the sleeve 53, and are generally cylindrical but provided with at spots 55. Cooperable with the ends of the core 52 are the links 5| each having an aperture 56 complementary to the cross-sectional form of the cooperating end of the core 52. Each link 5| also has an aperture 51 at the other end of the link.

The sprocket rim 46 is provided with a plurality of transverse cylindrical holes 58 of a size to flt and have inserted therein the sleeves 53 of the respective bushing 50. After a bushing 50 is inserted in one of these holes, 58, as shown in Figure 4, links 5| are assembled with the reduced ends of the core 52 of the bushing and a bolt 59 is inserted through the hollow center of the core 52. The bolt 59 is shown as threaded at both ends and nuts 60 cooperating with the threaded ends are provided to retain the parts assembled. The nuts 60 desirably bear against washers 6| which in turn bear against the respective ends of the core 52. For purposes of assembly. as will appear, it is desirable that the bushing 50 be rotatable in the hole 58 provided in the sprocket tial registry with a given hole 62. A pin 63 is then inserted through the apertures 51 and hole 58. The pins 63 may be retained in position by means of cotter pins 64; and washers 65 may be interposed between the cotter pins and the links 5|. The pins 63 are of a size so that they are slidable in the respective holes 62, and of course all of the pairs of links 5| are connected to the spider 44 as has been described in connection with a given pair of links. When the parts have been thus assembled each bushing 50 is held against rotation in its respective hole 58 by means of a set screw 2|, or in any other suitable way.

For the portions of the chain 43 extending between the sprocket wheels 4|, 42, that is, the tangent portions 66, 61, slack take-up means is provided. As here shown, this slack take-up means includes an idler sprocket 69 carried by and rotatable about a shaft 16, the ends of which are in turn carried by a pair of slidable blocks 1 I, 12 (see Figure 3). The slidable blocks 1|, 12 are here shown as slidable in guideways 13 formed in the respective opposite walls 31 38 of the housing 39. The idler sprocket 66 is biased transversely of the chain portion 61 so as to take up slack therein, by means here shown as a weight 14 which may be connected to the sliding blocks 1|, 12 in any suitable way as by means of the chain 15. The weight 14 may also be constructed so as to be guided in the guideways 13. Here shown as in engagement with the chain portion 66 is an idler sprocket 16 which is carried by and rotatable about a shaft 11 in turn carried by slidable blocks (not visible) similar to the blocks 1 12. The blocks which carry the shaft 11 of the idler sprocket 16 are slidable in guideways 18 in the walls 31, 38 of the upper portion of the housing 39, and these guideways are here shown as in vertical alinement with the guideways 13 in the lower portion of the housing. The upper idler sprocket, 16, is biased upwardly, transversely to the chain portion 66 which it engages, by means of a weight 19 suitably connected to the sliding blocks carrying the shaft 11 by a chain 8|), here shown as passing over a pair of sprockets 8|, 82 carried by auxiliary shafts. 'Ihe weight 19 may be guided by guideways 83 formed in the walls 31, 38 of the upper portion of the housing 39.

The operation of the embodiment shown in Figures 1 through 7 is as follows. As the prime mover causes rotation of the driving shaft 24., the chain 43, driven by the sprocket wheel 4|, causes torque to be applied to the sprocket rim 46, and thereupon the sprocket rim 46 will rotate relatively to the spider 44 a predetermined amount. Such rotation causes circumferential movement of the cores 52, force being of course transmitted thereto through the members 54, and, at the same time, the circumferential movement of the cores causes each pair of links 5| and the respective cores 52 associated therewith to turn about the axis of the respective core while the respective sleeve 53 is held against rotation with respect to the sprocket rim 46. The resilient members 54 accordingly resist relative rotation of the sprocket rim 46 and the spider 44, in either direction of rotation, and are placed under stress by said relative rotation. It is of course evident that the reaction of the stressed members 54 tends to bring the parts back to the neutral position shown in Figure 2. Upon relative rotation between the sprocket rim 46 and the spider 44, the pins 63 move radially outwardly in the holes 62 a certain amount, but, un-

I4. MAUHINt ilLtNltNl AND MECH/luxus Search Room less overload conditions exist, the pins 88 will not move outwardly far enough to engage the outer ends of the holes 82.

The-mount of relative rotative movement between the sprocket rim 48 and the spider 44, and the amount of the stress put upon the members 54 of the bushings 58 will depend upon the resisting torque of the spider, the resisting torque being in turn determined by such factors as the position of the crank and associated parts transmitting movement to the pump in the well 3|. the position of the pump piston, the load conditions, and so on. Assuming that the sprocket wheel 4| is rotated in a clockwise direction, increase in tension in the portion 81 of the chain will tend to lift the weight 14, and, conversely, decrease in tension will permit the weight to descend. With initial suitable tension in the chain 43, these motions are of course slight. Assuming, by way of example, a reduction in the resisting torque of the spiler 44, a predetermined decrease will result in a predetermined incipient speeding up of the spider tending to relative movement of the spider with respect-t`o the sprocket rim 48 while the sprocket rim tends to maintain its original relation with respect to the chain 43 and the wheel 4|, initially dueto the incipient unstressing reaction of the previously stressed members 54. Meanwhile, the reduction in tension in the chain portion 61 tends to permit the weight to descend, but meanwhile also, the sprocket wheel 4| tends to be speeded up by the prime mover 28, due to the reduction in tension. The parts thus assume a new relative position dependent upon the'varying conditions of resisting torque, without causing jumping or whipping of the chain.- In any event, whatever be the theory of operation, it has been found'that the cooperation and interaction of the parts, constructed and arranged as hereinbefore described, prevents jumping or whipping of the chain and the consequent frequent breaking of the chain, and. accordingly, makes feasible a drive of `the chain type under fluctuating and Ashock load conditions.

For example, hitherto. chain driven speed reduction units have never been successfully applied on oil well pumping units, because of frequent chain failure, and resort has been had to more expensive speed rduction apparatus, involving, for example, herringbone gears, which apfiaratus is not only more expensive, vbut involvs difilculties and expense in replacement of broken parts such as not involved in a chain type of drive.

Onlyy one slack take-up means is necessary if the apparatus is to be used for rotation of the sprocket wheel 42, as a whole, in but one direction, and two take-up means are necessary only where it is desired that the apparatus may be utilized for rotation of the sprocket wheel 42, as a whole, in either direction.

It will be understood that while a predetermined maximum number of holes 58, in the sprocket rim for example, and a corresponding predetermined maximum number of holes 82v in the spider for example, may Ibe provided, it is not essential that al1 of these sets of holes be utilized, that is, any desired number of cushion bushings 88 and associated links 5| may be used, up to a desired and suitable maximum number, so that the wheel.42 may be assembled to suit the conditions of operation to be met. Also, the disclosed construction alfords further means of used, but diil'erent links 5| may be used. For' example, the links 5| illustrated may be replaced by links of the same form but in which the hole 51 is located at a different distance from the center of the hole 56.

Referring now to the embodiment shown in Figures 8, 9, and 10. The sprocket wheel 42a shown in Figures 8 and 9, may take the place of the sprocket wheel 42. The sprocket Wheel 42a comprises a spider 44a having a peripheral cylindrical surface 84, and a sprocket rim 46a having a cylindrical surface 85 cooperable with the cylindrical surface of the spider, and, in this instance, if desired, a suitable bearing element 86 is shown as interposed between these surfaces. If, desired, the bearing element may be made of oilite. To control relative rotative movement as between the sprocket rim 48a and the spider 44a, a plurality of connections are made between the sprocket rim and the spider, as will now appear. Each of these connections comprises a cushioning unit 81, shown in perspective in Figure 10. This cushioning unit, 81, is here shown as comprising two metal plates 88, 88, preferably steel, between which is disposed a member 88 of resilient material. This member 88 is preferably made of material which may be molded to the plates 88, 88, and may be made of -such material as already set forth ln'connection with the member 54. The plate 88 is here shown as provided with two suitably spaced holes 8| through which project outwardly the threaded Shanks' 82 of two bolts the heads 88 of which are at the inside surface of the plate 88 `Where they are embedded in the resilient member 88.' The plate 88 is longer than the plate 88 extending beyond the ends of the resilient meinber- 88, and these extensions are provided withapertures 84. If desired, apertured washers 88 may Ibe disposed over and fastened to the extending portions ofthe plate 88.

Considering the connection between the spider 44a and the sprocket rim 46a, at the section illustrated in Figure 9, this connection includes two cushioning units 81 such as shown in Figure 10,

disposed on opposite sides of the spider 44a and fastened tothe spider by means of bolts 88 passing through the holes 84 in the cushioning units and registering holes 81 in the spider. 'I'he bolts 88 are provided with heads and nuts which bear against the respective washers 85. The connection further'includes a pair of plates 88, here shown as of triangular form, these plates having holes registering with the bolts 82 projecting from the respective cushioning units 81, each plate being fastened to the respective cushioning unit by means of the nuts 89 engaging the threaded bolts 82; Each connecting plate 98 is thus fastened to the respective plate 88 of a cushioning unit. The connecting plates 88 are also each provided with a hole |88, and these holes are alined with eachother and with a hole |8|, here shown as slightly elongated radially, passing transversely through the sprocket rim 46a, so that a bolt |82 may be passed through these registering holes. The bolts |82 is here shown as havlng a reduced threadedend which is provided with a nut |88 which bears against a washer |22 which in turn bears against the shoulder formed by the reduced end so that the bolt |82 and nut |88 are held assembled with the plates 88 but the plates are not tightened against the sprocket rim 48a, a desired amount of clearance being left.

As indicated in Figure 8, any desired and suitable number of cushioning connections may be made between the spider 44a and the sprocket rim The operation of the ring when a sprocket wheel 42a, such as shown in Figures 8 through 10, is utilized, instead of the wheel 42, is analogous to the operation already described in connection with the embodiment of Figures 1 through '1. It will be obvious that when, due to application of torque, there is relative rotative movement as between the sprocket rim 46a and the spider 44a, the plates 98 tend: to move the plates 89 in a circumferential direction and also tend to turn each plate 89 about an axis transverse to the approximate center of the lateral face of the respective plate 89. The resilient members 90 accordingly resist the relative rotative movement of the sprocket rim 46a and the spider 44a, in either direction of rotation, and are placed under stress by said relative rotation.

It will be evident that the embodiment of Figures 8 to 9 aiords adjustment to suit conditions analogously to the embodiment of Figures 1 to 1.

Referring now to the embodiment shown in Figures 11 and 12. A sprocket wheel 42h such as shown in Figures 11 and 12 may be utilized instead of the sprocket wheel 42. The sprocket wheel 42h comprises a spider Mb and a sprocket rim 4Gb, which have relatively rotatable cooperating cylindrical surfaces |04, |03, between which a bearing element |05 may be interposed as described in connection with Figures 8 and 9. The cylindrical surface |03 on the sprocket rim 4Gb is here shown as slightly recessed into the inner periphery of the rim. The sprocket rim 46h and the spider Mb are relatively rotatable, as in the previously described embodiments, and are likewise connected by means of a cushioning connection. In this instance, the cushioning connection comprises two resilient members |06 disposed on opposite sides of the spider Mb, each resilient member |06 being covered by an annular plate |01 having holes |08 through which project outwardly from the plate the shanks |09 of Screwthreaded bolts, the heads 0 of which are on the inner surfaces of the plates |01. As in the case of the embodiment of Figures 8 through 10, the resilient members |06 are molded to the parts between which they are interposed, that is, in this instance, they are molded respectively to the spider Mb and to the annular plates |01. The sprocket rim 46h is provided: with an annular ange having holes ||2 adapted to register with the bolts |09 projecting from one of the annular plates |01, and the other side of the sprocket rim 4Gb is adapted to have fastened thereto, by means of machine screws |l3, a ring ||4 having holes H5 adapted to register with the bolts |09 projecting from the other annular plate |01. 'Ihe annular flange l and ring Ill are fastened to the annular plates |01 respectively by the provision of nuts ||6 cooperating with the -bolts |09 projecting from the annular plates 01. It will be evidfent that when torque is applied to the sprocket rim 4Gb, relative rotative movement between the sprocket rim 4Gb and the spider 44h will take place until the tension on the resilient members 06 is sufficient to overcome the resisting torque of the spider 44h, and that the operation of the apparatus is analogous to that already described in connection with Figures l through 7.

From the foregoing it will be apparent to those skilled in the art that each of the illustrated embodiments of the invention provides a new and improved power transmission apparatus, and accordingly, each accomplishes the principal object of the invention. On the other hand, it also will be obvious to those skilled in the art that the illustrated embodiments of the invention may be variously changed and modified, or features thereof, singly, or collectively, embodied in other combinations than those illustrated, without departing from the spirit of the invention, or sacrificing all of the advantages thereof, and that accordingly, the disclosure herein is illustrative only, and the invention is not limited thereto.

I claim:

1. Power transmission apparatus, adapted for use under conditions wherein the relation between the load torque on said apparatus and the input torque to said apparatus is subject to sudden changes, comprising: rotatable driving wheel means; rotatable driven wheel means, including a first portion rotatable in unison with a driven shaft, andinoluding a rotatable second portion, and including means for interconnecting said portions, so constructed and arranged that said portions have a non-power transmitting position with respect to each other and are relatively rotatable to a limited extent away from said position; power transmitting band-means, about said driving wheel means and said second portion of said driven wheel means, so constructed and arranged that rotation of said driving wheel means is adapted to cause rotation of said driven wheel means; slack take-up means, including means engaging said band means between said two wheel means, and means biasing said engaging means in a direction to take up slack in said band means; and said means for interconnecting said portions comprising energy storing means so constructed and arranged that upon relative rotative movement of said rst and second portions away from said position energy is so stored that said portions are adapted to be returned to said position by reason of release of said energy.

2. Power transmission apparatus, adapted for use under conditions wherein the relation between the load torque on said apparatus and the input torque to said apparatus is subject to sudden changes, comprising: rotatable driving wheel means; rotatable driven wheel means, including a rst portion rotatable in unison with a driven shaft, and. including a rotatable second portion, and including means for interconnecting said portions, so constructed and arranged that said portions have a non-power transmitting position with respect to each other and are relatively rotatable to a limited extent away from said position; power transmitting band means, about said driving wheel means and' said second portion of said driven wheel means, so constructed and arranged that rotation oi said driving Wheel means is adapted to cause rotation of said driven wheel gaging said band means between said two wheel 'means, and means including a gravity biased weight, constructed andl arranged to bias said engaging means in a direction to take up slack in said band means; and said means for interconnecting said portions comprising energy storing means so constructed and arranged that upon relative rotative movement of said first and second portions away from said' position energy is so stored that said portions are adapted to be returned to said position by reason of release of said energy.

3. Power transmission apparatus, adapted for le. Mensur tLtMi- Nl AND MECHANISMS use under conditions wherein the relation between the load torque on said apparatus and the input torque to said apparatus is subject to sudden chmges, comprising: rotatable driving wheel means; rotatable driven wheel means, including a first portion rotatable in unison with a driven shaft, and including a rotatable second portion, and including means for interconnecting said portions, so constructed and arranged that said portions have a non-power transmitting position with respect to each other and are relatively rotatable to a limited extent away from said position; power transmitting band means, about said driving wheel means and said second portion of said driven wheel means, so constructed and arranged that rotation of said driving wheel means is adapted to cause rotation of said driven wheel means; slack take-up means, including means engaging said band means between said two wheel means, and means biasing said engaging means in a direction to take up slack in said band means; and said means for interconnecting said portions comprising a resilient member so constructed and arranged that upon relative rotative movement of said first and second portions away from said position said resilient member is stressed and torque of said second portion is transmitted to said rst portion through said resilient member.

4. Power transmission apparatus, adapted for use under conditions wherein the relation between u the load torque on said apparatus and the input torque to said apparatus is subject to sudden changes, comprising: rotatable driving wheel means; rotatable driven wheel means, including a first portion rotatable in unison with a driven shaft, and including a rotatable second portion, and including means for interconnecting said portions, said portions having a non-power transmitting position with respect to each other and being relatively rotatable to a limited extent away from said position; power transmitting band means, about said driving wheel means and said second portion of saidl driven wheel means, so constructed and arranged that rotation of said driving wheel means is adapted to cause rotation of said driven wheel means; slack take-up means, including means engaging said band means between said two wheel means, and means biasing said engaging means in a direction to take up slack in said band means; and said means for interconnecting said portions comprising a resilient member of molded plastic material so constructed and arranged that upon relative rotative movement of said first and second portions away from said position torque of said second portion is transmitted to said rst portion through said resilient member.

5. Power transmission apparatus, adapted for use under conditions wherein the relation between the load torque on said apparatus and the input torque to said apparatus is subject to sudden changes, comprising: rotatable driving wheel means; rotatable driven wheel means, including a first portion rotatable in unison with a driven shaft, and including a rotatable second portion, and including means for interconnecting said portions, said portions having a non-power transmitting position with respect to each other and being relatively rotatable to a limited extent away from said position; power transmitting band means, about said driving wheel means and said second portion of said driven wheel means, so constructed and arranged that rotation of said driving wheel means is adapted to cause rotation of said driven wheel means; slack take-up means,

Search Room including means engaging said band means between said two wheel means, and means biasing said engaging means in a direction to take up slack in said band means; said means for intervconnecting said portions comprising a plurality of unitary devices each comprising a resilient member so constructed and arranged that upon relative rotative movement of said rst and second portions away from said position torque of said second portion is transmitted to said iirst portion through said resilient member; and said unitary devices and said portions being relatively so oonstructed and arranged that said unitary devices are individually assemblable with and disassemblable from said portions whereby the torque necessary to cause relative rotative movement of said portions may be adjusted.

6. Power transmission apparatus, adapted for use under conditions wherein the relation between the load torque on said apparatus and the input torque to said apparatus is subject to sudden changes, comprising: rotatable driving wheel means; rotatable driven wheel means, including a first portion rotatable in unison with a driven shaft, and including a rotatable second portion, and including means for interconnecting said. portions, said portions being relatively rotatable to a limited extent; power transmitting band means, about said driving wheel means and said second portion of said driven wheel means, so constructed and arranged that rotation of said driving wheel means is adapted to cause rotation of said driven wheel means; slack take-up means, including means engaging said band means between said two wheel means, and means biasing said engaging means in a direction to take up slack in said band means; and said means for interconnecting said portions comprising a resilient member so constructed and arranged that it resiliently holds said portions in a denite relative rotative position and upon relative rotative movement of said first and second portions away from said position said resilient member is stressed and torque of said second portion is transmitted to said rst portion through said resilient member.

7. Power transmission apparatus, comprising: rotatable wheel means, including a rst portion rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a link and a connection between said link and one of said portions of said wheel means, and including a resilient member interposed between said link and the other portion of said wheel means, and being so constructed and arranged that relative rotation of-said portions puts said resilient member under torsional type stress and torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient member.

8. Power transmission apparatus, comprising: rotatable wheel means, including a first portion rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and' said interconnecting means including a link and a lost motion connection between said link and a generally radially extending slot in one of said portions of said wheel means, and including a resilient member interposed between said link and the other portion of said wheel means, so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient member.

9. Power transmission apparatus, comprising: rotatable wheel means, including a first portion rotatable in unison with a shaft, and including a rotatable second portion concentric with said first portion, one of said portions having a plurality of circumferentially spaced generally radially extending slots, said wheel means also including means for interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a selected plurality of circumferentially spaced generally radially disposed links and connections between said links and the other one of said portions of said Wheel means and lost motion connections between said links and selected ones of said slots, and including resilient members interposed between the respective links and said other portion of said wheel means, and being so constructed and arranged that torque of one of Said wheel portions is transmitted to the other of said wheel portions through said links and said resilient members.

10. Power transmission apparatus, comprising: a rotatable shaft; wheel means, including a rst portion having a peripheral bearing surface and being rotatable in unison with said shaft, and including a relatively rotatable second portion of generally annular form having an inner peripheral bearing surface cooperating with said iirst named bearing surface; and means for interconnecting said portions, including a metallic member and a resilient member of molded plastic material fastened by molding to said metallic member and interposed between said metallic member and one of said portions of said wheel means, and including a connecting member disposed laterally of said portions of said wheel means and connected to said metallic member and to the other one of said portions of said wheel means, so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said metallic member and said resilient member.

11. Power transmission apparatus, comprising: rotatable wheel means, including a rst portion rotatable in unison with a shaft, and including a rotatable second portion, and including means for interconnecting said portions, said portions having a non-power transmitting position with respect to each other and being relatively rotatable to a limited extent away from said position; said means for interconnecting said portions comprising a plurality of unitary devices spaced circumferentially with respect to one of said portions and each said device comprising a resilient member and means xedly connecting said member to said one of said portions, and being so constructed and arranged that upon relative rotative movement of said rst and second portions away from said position torque of said second portion is transmitted to said first portion through said resilient member; and said unitary devices and said portions being relatively so constructed and arranged that said unitary devices are individually assemblable with and disassemblable from said portions whereby the torque necessary to cause relative rotative movement of said portions may be adjusted.

12. Power transmission apparatus, comprising: rotatable wheel means, including a first portion rotatable in unison with a shaft, and including a rotatable second portion concentric with and in the general plane of said iirst portion, and including means for interconnecting said por tions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including two sets of links, said sets being disposed at opposite sides of said portions, and connections between said links and one of said portions of said wheel means, and including also resilient means interposed between said links and the other portion of said Wheel means, and being so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said links and said resilient means.

13. Power transmission apparatus, comprising: rotatable Wheel means, including a. first portion rotatable in unison with a shaft, and including a rotatable second portion, and including means for interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a generally radially disposed link and a connection between said link and one of said portions of said wheel means, and including a resilient member interposed between said link and the other portion of said wheel means, said resilient member having spaced surfaces a rst of which is fixedly connected to said other portion of said wheel means and a second of which is xedly connected to said link, said interconnecting means being so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient member.

14. Power transmission apparatus, comprising: rotatable wheel means, including a first portion rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a link and a first connection between said link and one of said portions of said wheel means, and a second connection between said link and the other portion of said wheel means, said second connection comprising spaced metallic members one of which is xedly connected to said other portion of said wheel means and the other of which is flxedly connected to said link, said second connection comprising further a resilient member spaced surfaces of which are iixedly connected to said metallic members respectively, said interconnecting means being so constructed and arranged that relative rotation of said portions puts said resilient member under torsional type stress and torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient member.

l5. Power transmission apparatus, comprising: rotatable wheel means, including a first portion rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a link and a rst connection between said link and one of said portions of said wheel means, and a second connection between said link and the other portion of said wheel means, saidsecond connection comprising spaced 74. MACHINE ELEHEIHS AND MECHANlSMS metallic members one of which is a tube extending substantially parallel to said shaft and fixedly connected to said other portion of said wheel meansld the other of which is a rod substantially coaxial with said tube and fixedly connected to said link, said second connection comprising further a resilient tubular member the outer and inner peripheral surfaces of which are iixedly connected to the inner and outer surfaces of said tube and rod respectively, said interconnecting means being so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient member.

16. Power transmission apparatus, comprising: rotatable wheel means, including a iirst portion rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a link and a rst connection between said link and one of said portions of said wheel means, and a second connection between said link and the other portion of said wheel means, said second connection comprising spaced metallic plates one of which is flxedly connected to a side of said other portion of said wheel means and the other of which is xedly connected to said link, said second connection comprising further a resilient member spaced surfaces of which are flxedly connected to said metallic plates respectively, said interconnecting means being so constructed and arranged that torque of one oi said wheel portions is transmitted to the other of said portions through said link and said resilient member.

17. Power transmission apparatus. comprising: rotatable wheel meansA including a rst portion Search Room rotatable in unison with a shaft, and including a rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a link and a lost motion connection between said link and a generally radially extending slot in one of said portions of said wheel means, and including substantially coaxial elements between which is interposed resilient means, one of said elements being connected to said link and the other of said elements being connected to the other portion of said wheel means, said interconnecting means being so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient means.

18. Power transmission apparatus, comprising: rotatable wheel means, including a flrst portion rotatable in unison with a shaft, and including a. rotatable second portion, and including means interconnecting said portions, so constructed and arranged that said portions are relatively rotatable to a limited extent; and said interconnecting means including a. link and a lost motion connection between said link and a generally radially extending slot in one of said portions of said wheel means, and including spaced plates between which is interposed resilient means one of said plates being connected to said link and the other of said plates being connected to the other portion of said wheel means, said interconnecting means being so constructed and arranged that torque of one of said wheel portions is transmitted to the other of said portions through said link and said resilient means.

JAMES r'. SMITH.

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