text: referring to fig1 reference numeral 12 denotes a schematic of a top driven drilling machine or power swivel and a stand of pipe 14 coupled to a drill string 18 by a tool joint 16 . drill string 18 is rotated into a well 20 with a drill bit 22 connected to the bottom end of drill string 18 . pipe stand 14 may include one or more lengths of drill pipe . power swivel 12 is vertically suspended in a derrick 24 including a floor 26 having a slip bowl 28 and slips 30 . power swivel 12 is guided during vertical movement by a pair of parallel tracks 32 and suspended from a wire rope 34 reeved over a crown block 36 with rope 34 wrapped around a drawworks 38 . fig2 shows details of power swivel 12 which generally includes a motor drive assembly for rotating drill string 18 and a handling system for supporting drill string 18 . the motor drive assembly includes a drill motor 40 , a swivel bearing 42 and a sub assembly 44 for threadably connecting drill motor 40 to drill pipe 14 . the handling system includes a housing 46 for supporting swivel bearing 42 , a handling ring 48 , an elevator 50 for supporting pipe 14 , and a pair of elevator links 52 for suspending elevator 50 from handling ring 48 . a make - break device 54 and grabs 56 are supported by handling ring 48 for connecting and disconnecting sub assembly 44 to pipe 14 . the handling system also includes a traveling block 58 and a pair of support links ( not shown ) for suspending housing 46 from traveling block 58 . power swivel 12 is remotely operated from a console ( not shown ) on rig floor 26 . power swivel 12 is lifted or lowered by traveling block 58 within derrick 24 and well 20 is deepened by the powered rotation of drill pipe 14 by drill motor 40 . power swivel 12 is guided by tracks 32 and the torque generated by drill motor 40 is resisted by tracks 32 and derrick 24 . fig3 shows power swivel 12 of fig2 with tracks 32 removed to show the preferred arrangement of the guide means including an adjacent pair of rotatably mounted rollers 62 , 64 and a rotatably mounted roller 66 positioned against each track 32 at or above drill motor 40 . a similar arrangement of rollers is shown positioned on swivel bearing housing 46 . fig4 shows detail of the upper guide means in fig3 . fig3 illustrates a symmetrical assembly on opposite sides of drill motor 40 and a similar assembly mounted on housing 46 . since each assembly of rollers is an allochiral arrangement , an explanation for any one assembly applies equally to the remaining ones . roller 66 is mounted to a stanchion 68 by a nut 70 secured to a threaded bolt 72 . stanchion 68 is fastened , such as by welding or bolting , to a spring 74 which is secured to a frame 60 by a bracket 76 and fasteners 78 . rollers 62 , 64 are similarly mounted onto springs 74 by stanchions 68 . spring 74 preferably is a composite of two leaf springs 80 , 82 which are spaced apart by a shim 84 . composite springs , or multiple stage springs , are preferably used because primary spring 80 is relatively weak and provides only limited resistance to rotation of power swivel 12 . this allows power swivel 12 to move under light loads and insures that rollers 62 , 64 , 66 have only minimal loading at positions where they are &# 34 ; pinched &# 34 ; into a space smaller than their normal spacing . primary springs 80 are too small to fully dissipate the energy required to reduce the torque loading and secondary springs 82 are provided for this purpose . thus , power swivel 12 is resisted by weaker primary spring 80 in the initial part of the travel by power swivel 12 . after a predetermined amount of travel , power swivel 12 is resisted by the combination of spring 80 and spring 82 . primary spring 80 is mostly to accommodate abberations in tracks 32 and secondary spring 82 is mostly for dissipating torque loads of power swivel 12 . it will be understood various materials can be used for the springs . for example , several steel alloy compositions having various heat treated conditions being possible . in some situations , natural rubber , synthetic rubber , or a graphite - epoxy composite may be desirable . depending on geometry and space requirements of the power swivel , any one of such springs as belleville , gas , liquid , coil or torsional could also be used . the critical requirement for the spring is that it exert the required amount of force over the required amount of deflection . those skilled in the art refer to this as &# 34 ; spring rate &# 34 ; ( force per unit length of travel ) with the spring rate for each design being easy to determine . fig6 shows a top view of a guide assembly within track 32 . track 32 is an h - beam 86 including a pair of spaced flanges 88 , 90 integral with a web 92 . those skilled in the art will appreciate that various other structural members such as square tubing , rectangular tubing , and the like could also be used as track 32 . rollers 62 , 64 are urged against flanges 88 , 90 respectively and roller 66 is urged against web 92 . deflection of tracks 32 resulting from torque of drill motor 40 or misalignment of tracks 32 resulting from environment stress can cause rigidly mounted rollers of the prior art to become disengaged from tracks 32 . this causes increased wear if the rollers bind or rebound between tracks 32 . springs 74 of the invention act as shock absorbers allowing power swivel 12 limited motion while being guided by tracks 32 . fig7 a and 7b are similar to fig4 except a cross - section of web 92 of track 32 is shown . fig7 a and 7b illustrate how springs 74 maintain rollers 62 , 64 , 66 into continuous rolling contact with track 32 . fig7 a shows the relationship of roller 66 relative to web 92 before power swivel 12 is installed onto tracks 32 . the length of stanchion 68 is greater than the spacing between spring 74 and web 92 . fig7 b shows power swivel 12 installed onto tracks 32 . when power swivel 12 is mounted onto tracks 32 and roller 66 contacts web 92 , primary leaf spring 80 of spring 74 is slightly flexed or bent away from web 92 to its normal or biased position toward ( but not quite touching ) secondary spring 82 . as indicated above , yielding of primary spring 80 should accommodate most abberations in tracks 32 . during drilling , secondary spring 82 will also yield with the heavy torque load generated by drill motor 40 being resisted by the combination of springs 80 and 82 . it will be understood rollers 62 , 64 will be similarly urged into contact with flanges 88 , 90 . a further embodiment of the invention is incorporation of a damping device ( not shown ) with the spring . the spring causes the power swivel to constantly do work as the power swivel moves . this work is recaptured as the power swivel moves in the opposite direction . a damping device also causes the power swivel to do work with this latter work converted to heat energy . those skilled in the art of suspension systems will recognize the potential benefit of a single device which accomplishes both a spring function and a damping function . as with springs , the damping device could by any one of a liquid , gas or mechanical type with the common element being the ability of the device to convert mechanical energy to heat energy . it will be understood various modifications may be made to the invention without departing from the spirit and scope of it . therefore , the limits of the invention should be determined from the appended claims .