US3142210A

US3142210A - Power operated wrench with two-speed drive

Info

Publication number: US3142210A
Application number: US204565A
Authority: US
Inventors: James S Rodgers
Original assignee: Rodgers Hydraulic Inc
Current assignee: Rodgers Hydraulic Inc
Priority date: 1962-06-22
Filing date: 1962-06-22
Publication date: 1964-07-28
Anticipated expiration: 1981-07-28

Description

July 28, 1964 J. 5. RODGERS 3,142,210

POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 1 32 F1 5'. l 40 I 206 ms E 34 l I 4 96 20o INVENTOR. fins: .5. 200052:

flrramvars July 28, 1964 J. S. RODGERS POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 2 July 28, 1964 J. s. RODGERS 3,142,210

POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 3 INVENTOR. Jhmss S. Rona-ks 236 flrromvar:

July 28, 1964 t J. 5. RODGERS 3,142,210

POWER ppsmwzu WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 4 z4a\ f g l f e 1| l il h// Il 262 INVENTOR.

fines .51 P004625 Arman/er:

y 1964 J. 5. RODGERS 3,142,210

POWER OPERATED WRENCH WITH TWO-SPEED DRIVE Filed June 22, 1962 5 Sheets-Sheet 5 2 N "3 :2 v m a N a N m V N h at Q- N a ll g g n INVENTOR.

JAME: .5. Row

Jrroawer:

ed S te Paten 3,142,210 POWER OPERATED WRENCH WITH TWO-SPEED DRIVE James S. Rodgers, Adams Run, S.C., assignor to Rodgers Hydraulic, Incorporated, Minneapolis, Minn., a corporation of Minnesota Filed June 22, 1962, Ser. No. 204,565 2 Claims. (Cl. 8157) The present invention relates to wrenches and more particularly to power operated wrenches of the type supported for movement relative to a workpiece for performing work in different areas of the workpiece. The invention has particular utility in the assembly and repair of tractor treads.

In the assembly and disassembly of various articles of manufacture such as the treads of a tractor, it is a common practice to employ a power operated wrench such as an impact wrench. Some of these wrenches must be lifted and moved by hand from one bolt to the next as the work proceeds. Carrying such a wrench by hand can I.

While the invention has general application, it is particularly well adapted for the removal and replacement of the grouser plates of tractor tread. Due to the abrasive nature of the soil in which track vehicles frequently operate, various parts of the tread rapidly become worn and therefore require relatively frequent replacement or resetting. The repair operation is begun by removing the tractor treads from the vehicle. The grouser plates are removed and the pins and bushings are then removed from the rails through the use of a track press of the general type described in the copending application of Vernon K. Quarve and John L. Rodgers, Jr., Serial No. 716,711, filed February 21, 1958, for Track Press, and assigned to the same assignee as the present application.

Among the problems involved in the repair of tractor treads are the following. The bolts which secure the grouser plates to the rails are often bent or misshapen and frequently are frozen or rusted in place. The wrench must therefore be relatively powerful in order to provide the torque required to loosen the bolts. At the same time the wrench must be readily adapted for movement from one point on the tread to another.

Moreover, operation of the wrench should not damage the bolts or the wrench socket either while the bolts are being applied or while they are being loosened. In order to reduce the time required for tightening and loosening the bolts, it is desirable to provide greater torque at reduced speed for initially loosening the bolt and an increased operating speed for final removal of the bolt.

Accordingly it is one object of the present invention to provide an improved power operated wrench with a support for positioning the wrench above a workpiece and including a means for allowing the wrench socket to be moved on a path extending normal to the workpiece as well as laterally with respect to the workpiece.

It is another important object of the present invention to provide an improved power operated wrench including a supporting framework, a wrench drive head mounted thereon with a socket carrying member at the lower end of the drive head and a means for raising and lowering the socket carrying member relative to the 3,142,210 Patented July. 28, 1964.

wrench drive head so as to enable the socket to be readily shifted from one bolt to the next.

It is yet another object of the present invention to provide an improved power operated wrench assembly including a means for providing high torque for breaking the bolts loose and greater rotational speeds for final removal of the bolts.

It is yet another object of the present invention to provide an improved power operated wrench having a drive motor, a wrench drive head connected for transverse movement with respect to the motor and a reversing transmission connected between the drive motor and the wrench drive head.

It is yet another object of the present invention to provide an improved power operated wrench adapted to readily remove rusted or otherwise tightly retained bolts with little tendency to damage either the bolts or the wrench socket.

It is still another object of the present invention to provide an improved power operated wrench which can be moved longitudinally of the workpiece and will have no tendency to bind on the supporting rails.

It is yet another object of the present invention to provide an improved power operated wrench including a supporting framework with a drive motor mounted thereon, a wrench drive head pivotally mounted upon the framework for swinging movement about a vertical axis and a coupling means connecting the motor to the drive head regardless of the angular position of the drive head with respect to the framework.

These and other more detailed and specific objects will be disclosed in the course of the following specification, reference being had to the accompanying drawings, in which FIG. 1 is a side elevational view of an apparatus embodying the present invention.

FIG. 2 is an end elevational view taken on line 22 of FIG. 1.

FIG. 3 is a plan view of the apparatus of FIG. 1.

FIG. 4 is a partial vertical longitudinal sectional view taken on line 4-4 of FIG. 2.

FIG. 5 is a partial sectional view taken on line 5-5 of FIG. 3.

FIG. 6 is a partial transverse vertical sectional view taken on line 66 of FIG. 4.

FIG. 7 is a partial perspective view of the outward portion of the operators control handle.

FIG. 8 is a partial elevational view taken on line 83 of FIG. 3.

FIG. 9 is a combined electrical and hydraulic schematic diagram for the apparatus.

Referring now to the drawings and particularly FIGS. 1, 2 and 3 which illustrate by way of example a preferred form of the present invention, there is shown a power operated wrench including a supporting framework or carriage indicated generally at 10. The supporting framework 10 includes four downwardly extending legs 12, one such leg being provided at each corner of the framework 10. The framework 10 is provided with a plurality of transversely extending braces 14, one of which can be seen in FIG. 2. Other braces and cross members can be placed where necessary to provide a requisite strength as will be apparent to those skilled in the art.

At the upper ends of the legs 12 there is provided a horizontally disposed metal covering sheet 16. Sheet 16 bends downwardly along each

side edge

18 and 20. Below the sheet 16 is provided a hydraulic fluid storage reservoir 22 into which hydraulic fluid can be introduced through suitable covered filling spouts 24 and 26. A pair of laterally spaced apart longitudinally extending rails 27 project downwardly from the carriage 10. The position of each of rails 27 is laterally adjustable so that the spacing therebetween can be made to fit workpieces of different sizes, thereby preventing the torque produced by the wrench from twisting the workpiece relative to the carriage 10.

At the forward and rearward ends of the carriage 10 and extending upwardly from the covering sheet 16 are provided four spaced apart vertically positioned braces 28. The lower ends of braces 28 are rigidly secured to the carriage 10 adjacent the forward and rearward edges of the covering sheet 16. A support plate 30 is pivotally secured at 30 to the upper ends of braces 28 on one side of the apparatus to provide a drive belt tension adjustment. Suitable covering sheets 31 are provided for enclosing a speed changing and reversing transmission as described hereinbelow. Rigidly secured to the upper surface of the support plate 30 is a drive motor 32 including an output shaft 34 positioned in a horizontal plane and extending longitudinally of the apparatus. Current can be applied to the motor 32 through a conductor 33 connected to the motor 32 through a start and stop switch assembly 36 and a conduit 38.

A sheave 40 is mounted upon the motor shaft 34 at one end thereof and a similar sheave 42 of a smaller diameter is mounted upon the opposite end as best seen in FIG. 1. Entrained over the sheaves 40 and 42 and extending downwardly therefrom are a pair of

flexible belts

44 and 46 respectively. As can be seen in FIG. 4, the belt is entrained also over a sheave 48 positioned below the motor 32 and the belt 46 is entrained over a sheave 50 of a larger diameter than the sheave 48.

As can be best seen in FIG. 4, the apparatus is provided with a clutch and speed changing mechanism indicated generally at 52. The speed changing mechanism 52 includes a clutch shaft 54 mounted for rotation on a horizontal axis and supported at each end upon hearing blocks 56 and 58. The bearing block 56 is suitably connected to a support member 60 while the bearing block 58 is suitably supported upon the rearward wall of a reversing transmission 62. A suitable friction reducing bearing can be provided at 64 within bearing block 56.

Rigidly secured to the shaft 54 are a pair of axially spaced apart radially extending

clutch plates

66 and 68. Operatively associated with each of the clutch plates are a pair of

clutch discs

70, 72, 74 and 76 respectively. Each of the clutch discs is provided with an integral clutch sleeve designated at 78, 80, 82 and 84 respectively. The sleeves are rotatably mounted upon the clutch shaft 54 by means of suitable sealed bearings 86 which do not require periodic lubrication and thus prevent lubricant from coming in contact with the clutch friction surfaces. The bearings 86 of the sleeves 80 and 82 are slidably mounted upon the clutch shaft 54 thereby enabling each of the

clutch discs

72 and 74 and the associated sleeves 80 and 82 to slide axially of the clutch shaft 54 a limited distance.

The outer ends of the adjacent clutch discs 70 through 76 are connected by means of bolts 90 which extend parallel to the axis of the shaft 54 through suitable circumferentially spaced apart aligned openings in the sev eral discs. The outer ends of each bolt 90 are provided with suitable connecting means such as a nut 92. The bolt 90 functions as a means for preventing relatively rotational movement between the associated clutch disc and also serves to limit the extent to which the associated pairs of clutch discs can be separated from each other. They do not, however, limit the distance that the clutch discs of each pair can move toward each other. Suitable resilient members such as springs 93 are mounted between the associated clutch discs for the purpose of urging the associated discs apart.

Within the outermost ends of the sleeves 78 and 84 are provided suitable bearings such as roller bearings 94 and 96 for reducing friction between the clutch shaft 54 and the sleeves. The sheaves 48 and 50 are mounted rigidly upon the outward extensions of sleeves 78 and 84 respectively. Other friction reducing bearings can be provided where necessary on the shaft 54 as will be apparent to those skilled in the art.

At the approximate center of the shaft 54 is rotatably mounted a clutch operating collar 100. The clutch operating collar 100 is pivotally mounted by means of a pivot 102 upon a clutch operating lever 104. The uppermost end of the lever 104 is pivotally mounted at 106 upon a suitable mounting block 108 rigidly secured to the mounting plate 30. Abutting against either side of collar 100 are a pair of thrust bearings 110 and 112. Positioned between the thrust bearings 110 and 112 and the innermost end of the sleeves 80 and 82 are provided suitable spacers 114 and 116 respectively for transmitting the thrust exerted by the operating lever 104 to the

clutch discs

72 and 74.

The lower end of the clutch operating lever 104 is pivotally connected at 118 to the output shaft 120 of a clutch operating actuator or cylinder 122. The cylinder 122 is in turn pivotally connected at 124 to a suitable bracket member 126 rigidly afiixed upon the carriage 10. The actuator 122 can be operated either by means of compressed air or hydraulic fluid but preferably by means of the latter. Suitably connected to the actuator 122 are provided a pair of fluid supply lines 128 and 130.

As best seen in FIGS. 4 and 6, at the forward end of the clutch shaft 54 is provided a reversing means or transmission 62 including a gear casing having side walls 138, a forward wall 139 and a rear wall 140. To the forward end of the shaft 54 within the casing of the reversing transmission 62 is rigidly secured a pinion gear 142. R0- tatably mounted upon the shaft 54 between the gear 142 and the rear wall is a gear carried member 144. The carrier member 144 has rotatably mounted thereon a pair of transversely spaced apart gears 146 and 148. Gear 148 is positioned in driving engagement with gear 142 and the gear 146 is mounted in driving engagement with the gear 148 but out of engagement with the gear 142.

A gear 150 is rotatably mounted at the upper end of the reversing transmission upon a shaft 152. When the gear carrier 144 is pivoted about the clutch shaft 54 in a counterclockwise direction to the position shown in FIG. 6, the gear 148 will be placed in driving engagement with a gear 150. When the gear carrier 144 is pivoted in a clockwise direction, as viewed in FIG. 6, the gear 148 will be disengaged from the gear 142 and the gear 146 will become engaged with the gear 150 thereby reversing the direction and rotation of the gear 142 and the shaft 152. Shaft 152 can be suitably mounted upon

friction reducing bearings

154 and 156 within the forward wall 139 of the transmission casing. The forward end of the shaft 152 is provided with a universal joint 158.

Rotatably mounted within the casing of the transmis sion 62 upon a bracket 160 is a control arm 162 which extends vertically within the casing and out through the upper end of the casing at 164. The outer end of the control arm 162 has suitably secured to it a control handle 166 as can be seen in FIGS. 1, 3 and 4. The lower end of the control arm 162 is provided with a forwardly curved portion 168 which projects into a recess 170 at the upper end of the gear carrier 144. It will thus be apparent that when an operator moves the control handle 166 and control lever 162 in a clockwise direction, as viewed in FIG. 3, the gear carrier 144 will pivot in a counterclockwise direction, as seen in FIG. 6, causing the gear 148 to become engaged with the gear 150. Upon reverse movement of the control handle 166, the gear 146 will engage the gear 150.

Pivotally mounted at the upper end of the carriage 10 and extending forwardly therefrom is a wrench drive head indicated generally at 175. The wrench drive head is mounted upon a pair of vertically spaced apart

bracket members

180 and 182 which extend forwardly from the forward wall of the transmission 62.

The drive head includes a swing base member 183 provided with a pair of vertically spaced apart rearwardly extending projections 188 at its upper end and a pair of vertically spaced apart rearwardly extending projections 190 at the lower end thereof. Projections 188 extend over the top and bottom of the bracket 180 and are secured thereto by means of a pivot pin 184. The members 198 extend around the bracket 182 and secured thereto by a pivot pin 186.

Extending forwardly from the swing base member 183 are a pair of horizontally disposed parallel and transversely spaced apart support members such as

rods

192 and 194. Mounted upon the

rods

192 and 194 is a gear casing 196 including an upper Wall 198, side walls 200 and a base member 202 having a pair of parallel transversely spaced apart openings within which the

rods

192 and 194 are positioned as best seen in FIGS. 2 and 5.

The side wall 200 of the casing 196 is bored at 204 to receive a drive shaft 206 which extends forwardly from the universal joint 158. The end of the drive shaft 206 within the gear casing 196 has secured to it a bevel pinion gear 208. The gear 208 is positioned in engagement with a ring gear 210 rigidly secured to a vertically disposed wrench output shaft 212.

The upper end of the shaft 212 has rigidly secured to it at 214 a shaft 216 which projects through an upper wall 198 of the gear casing. To the upper end of the shaft 216 is rigidly secured a handwheel 220 to enable the operator to manually adjust the position of the wrench socket for placement upon a bolt before power is applied to the wrench. The shaft 212 can be suitably rotatably mounted upon

friction reducing bearings

222 and 224.

Upon the lower end of the base member 202 is secured a fitting 226 suitably bored at 228 thereby allowing the lower end of the shaft 212 to project outwardly through the lower end thereof. The extreme lower end of the shaft 212 is provided with a square cross-sectional configuration 230. Upon the square portion the shaft 230 is slidably mounted a socket supporting member 232. The member 232 is provided with a bore of a square crosssectional shape so as to allow sliding movement between the shaft 212 and the member 232 but, at the same time, preventing rotation between these members.

Upon the lower end of the member 232 there is rotatably mounted a sleeve 234 to which a bracket 238 is secured by means of a pair of coaxial horizontally spaced apart pivot pins 236. The pins 236 also pivotally secure the bracket 238 to a pair of parallel horizontally spaced apart lever arms 240. At one end of the lever arms 248 is secured a generally diagonally extending pair of lever arms 244. The upper ends of these arms are pivotally secured at 246 to the lower end of the fitting 226.

Secured to the lower end of the fitting 226 is a bracket 248 for rotation relative thereto about a vertical axis and connected between the

brackets

248 and 238 are a pair of vertically extending parallel and transversely spaced apart resilient members such as springs 251 and 252. The

springs

250 and 252 urge the bracket 238, collar 234 and the associated members upwardly onto the portion 230 of the shaft 212 thereby yieldably biasing these parts upwardly and away from the workpiece. Upon the lower portion 254 of the socket support member 232 is detachably secured a suitable wrench socket 256 of any required size.

As best shown in FIGS. 1, 2, 3 and 7, at the outer end of the lever arm 240 is rigidly secured a switch enclosure 260 within which is mounted a three position selector switch 262. Extending outwardly from the outer end of the enclosure 260 is a tube 264 within which is rotatably mounted an elongate control handle 266. The inner end of the control handle 266 is operatively connected to the switch 262. By twisting the control handle 266 in one direction, the wrench output shaft 212 can be made to run at slow speed and by twisting the control handle 266 in the opposite direction, the output shaft can be made to run at a faster speed as will be described more fully hereinbelow. When the control handle 266 is turned to an intermediate position, neither of the clutches will be engaged and the wrench output shaft 212 will stop turning.

As can be best seen in FIGS. 1, 2, 3 and 8, at the lower end of the carriage 10 is rigidly secured a pair of laterally spaced apart horizontally disposed

frame members

280 and 282. Rotatably mounted at opposite ends of the

respective frame members

280 and 282 are a pair of wheels 284, one pair being provided on each of the

members

280 and 282. Since each side of the apparatus is provided with identical wheels and Wheel operating means, only the wheel mechanism on one side of the apparatus will be described in detail.

Each of the wheels 284 has rigidly secured to it a sprocket 286. Each of the wheels 284, at the forward end of the carriage 10, are provided with a second sprocket 288 positioned adjacent the sprocket 286. Spaced forwardly of each of the front wheels 284 is a handwheel 290. Each handwheel 290 is rotatably mounted upon the

respective frame members

280 and 282 for rotation on a horizontal axis upon a support shaft 292. Rigidly secured to each shaft 292 is a sprocket 294. Entrained between the

sprockets

294 and 288 on each side of the carriage 10 is a drive chain 296 and entrained over the sprockets 286 on each side of the carriage is a drive chain 298.

To the extreme forward and rearward ends of the

frame members

280 and 282 are rigidly secured a pair of mounting blocks 300. Each of the mounting blocks 300 has mounted at the upper end thereof for rotation about a vertical axis, an anti-bind wheel 302 positioned in tangential abutting relationship with the vertical wall of one of a pair of supporting rails 304 as can be seen in FIGS. 1, 3 and 8. The wheels 284 are adapted to rest upon the lower wall of the supporting rail 384 to thereby support the carriage 10 for longitudinal movement along the rails. The rails 304 are suitably supported above the floor or other surface by means of a plurality of supporting legs 306. Rotatably mounted between the rails 304 are a plurality of horizontally disposed transversely extending rollers 398. Thus when the apparatus is to be used, a workpiece, such as a section of tractor track 310 as shown in FIG. 1, can be moved over the rollers 308 to the desired position below the wrench drive head 175. As the repair operation continues, the carriage 10 can be moved along the rails 304 longitudinally of the workpiece 310 by turning either of the handwheels 290.

The electrical hydraulic system can be best understood by reference to FIG. 9. In FIG. 9 there is shown a power supply line 318 which can be connected to a suitable source of current (not shown). The conductors 318 are connected through a knife switch 320 to the drive motor 32. Each of the conductors 318 is provided with a solenoid operated switch 322 of any suitable known construction. In series with the switches 322 are provided suitable fuses 324. Connected across the conductors 318 are conductors 326 and 328. Connected in series between the lines 326 and 328 is a stop switch 330, a starting switch 332 and a relay 334. In series with the switch 332 is a holding coil 335 of conventional known construction. Additional fuses are provided at 338, 340 and 342. The armature of relay 334 is connected to the switches 322 by a connecting member 337. Wired to the conductor 326 is a conductor 343 leading to one terminal of each of

solenoids

344 and 346.

Solenoids

344 and 346 are both operatively connected to a four-way hydraulic valve 348 of known construction. The other terminals of

solenoids

344 and 346 are coupled by conductors 350 and 352 respectively through the three position selector switch 262 to the conductor 328.

The hydraulic system includes a suitable hydraulic pump 35 coupled to the shaft of the motor 32 and connected between an inlet line 360 leading to the storage reservoir 22 and a line 362 leading to the valve 348. The outlet of valve 348 is connected through a line 366 to the reservoir 7 22. The line 128 communicates between one end of the actuator 122 and the valve 348 while the line 130 communicates between the valve 348 and the other end of actuator 122. Communicating with the pump outlet line 362, as seen in FIGS. 1 and 9, is a pressure gauge 368 and a pressure control valve 370 of a suitable known construction. Valve 370 will permit an operator to control the hydraulic pressure in line 362 and in turn the pressure exerted by the actuator 122 upon the clutch discs. Lower pressures can be employed when bolts of a relatively small size are being tightened so as to allow the clutches to slip and thus avoid breakage of the bolts.

Operation While the apparatus according to my invention can be used to perform work on different types of workpieces, it will be described with particular reference to the assembly and repair of tractor treads.

When the apparatus is to be used, the tractor tread 310 is placed on the rollers 308 and moved to the position illustrated in FIG. 1 with the bolts which are to be removed positioned beneath the socket 256 of the wrench. After a bolt has been removed, the carriage 10 of the apparatus can be moved longitudinally of the workpiece by turning either of the handwheels 290 to quickly and efliciently position the socket 256 in position to receive the next bolt. At the same time the wrench drive head 175 can be swung about the pivots 184 and 186 to the left or right as required. When the wrench socket 256 is positioned directly over a bolt on the workpiece 310, the handwheel 220 can be turned manually to place the socket 256 in the position required to exactly fit over the bolt. The handle 264 can then be lowered manually against the retention of

springs

250 and 252 to place the socket 256 over the head of a bolt.

The motor 32 can be started by closing

switches

320 and 322. If the bolt is to be loosened, the reversing transmission control lever 166 is pivoted in the direction required to cause the socket 256 to rotate in a counterclockwise direction as seen in FIG. 3. The portion 266 of the control handle 264 is then twisted in a first direction so as to actuate solenoid 344. This will draw the plunger of valve 348 to the left (FIG. 9) and cause the output shaft 120 of actuator 122 to move toward the right as seen in FIG. 4, thereby engaging the

clutch discs

74 and 76 with a clutch plate 78. Under these conditions, the

clutch plates

70 and 72 will be released from engagement with the plates 76 and with the motor 32 in operation, power will be transmitted through belt 46 to sheave 50 and in turn to the clutch shaft 54 through gear 142 and one of the gears 146 or 148 to the gear 150. Rotation of gear 150 will in turn rotate the shaft 152, universal joint 158 and drive shaft 206. The drive shaft 206 will in turn rotate the pinion gear 208 and ring 210 thereby turning the wrench output shaft 212 and the socket member 232.

After the bolt has been initially loosened, lever 266 can be twisted in the opposite direction thereby actuating the selector switch 262 to supply current to the solenoid 346 rather than solenoid 34-4. This will cause the output shaft 120 of actuator 122 to move toward the left as seen in the drawings thereby engaging the

clutch discs

70 and 72 with the clutch plate 66. Under these conditions power will be transmitted to the shaft 54 through the belt 44 thereby causing the shaft 54 to rotate at a higher speed. As a result, the bolts which have been loosened can be removed more quickly and efiiciently. The handle 266 can then be twisted to an intermediate position thereby interrupting the current to both of

solenoids

344 and 346. The lever 104 will then move to an intermediate position and both clutch assemblies will be disengaged so as to halt rotation of the output shaft 212.

The present invention provides a number of important advantages. The speed changing assembly as disclosed herein provides an inexpensive method of obtaining two driving speeds as contrasted with a gear type transmission. Furthermore, the change from one speed to another is almost instantaneous. If it were necessary to release a clutch, shift gears and then reengage the same clutch, a much slower response would be provided than in the speed changing assembly according to the present invention. Moreover, by providing both high and low speeds at the wrench socket, additional power will be provided for breaking loose rusted bolts and, furthermore, slow speed operation has ben found desirable for loosening certain relatively large bolts which have been found to overheat if turned at relatively high speeds.

Another advantage of the invention derives from the fact that since the bracket 248 and lever

arms

240 and 244 can be rotated about a vertical axis on the fitting 226, the handle 266 can be moved to either side of the apparatus so that the bolts may be readily removed by an operator positioned on either side of the workpiece. It is also an important feature of the invention that the wrench can be operated entirely by a single control, thereby making it possible for an operator to control the wrench operation with one hand and hold the nuts from turning with the other hand, thus eliminating the requirement for a helper.

Another important feature of the invention is that the socket and its driving shaft are maintained perpendicular to the workpiece throughout operation. As a result, the relative movement between the socket and the head of the bolt being worked on will be held to a minimum. This provision has been found to add significantly to the life of the socket. Furthermore, the steady movement of the wrench socket makes it possible for the socket to drive bolts which a conventional impact wrench could not turn because the jar produced by an impact wrench would cause the socket to turn on a worn bolthead. It has been found that the steady movement of the Wrench socket also makes it less diflicult to hold the nuts of the bolts. The sockets, when used with my invention, will last very much longer than the sockets of a conventional impact wrench. It has been found that it will often require two or more sockets for a single tractor tread when a conventional impact wrench is employed, whereas in my invention, on the other hand, the sockets appear to last indefinitely.

The torque control through the regulation of hydraulic pressure on the clutch plates, according to my invention, serves as a means for protecting small or weakened bolts and, even more important, it assures that the bolts will be tightened to the proper degree for the particular size bolt employed. The regulation of the pressure on the clutch plates as disclosed herein thus enables all of the bolts in a tractor tread to be tightened to the same torque without depending upon the skill of the operator, as is commonly done when a conventional impact wrench is employed. It will, of course, be understood by those skilled in the art that the bolts must be properly tightened to prevent the grouser plates from working loose.

It is understood that suitable modifications may be made in the structure as disclosed, provided such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:

l. A power operated wrench comprising in combination; a supporting framework; a drive motor rigidly mounted upon said supporting framework; a drive head pivotally connected to one end of said framework for movement about a vertical axis with respect to said framework, said drive head extending outwardly from said supporting framework; a vertically disposed Wrench out put shaft rotatably mounted within said drive head, a horizontally disposed shaft in driving engagement with said wrench output shaft and rotatably mounted within said wrench drive head; drive means rotatably mounted upon said framework and operatively connected to said drive motor for rotation therewith; a flexible coupling means connected between said drive means and said horizontally disposed shaft; a socket supporting member s1idably mounted upon the lower end of said wrench output shaft; means coupling said socket supporting member and said wrench output shaft for preventing relative rotational movement therebetween and a control member operatively connected between said drive head and said socket supporting member for sliding said socket supporting member axially of said wrench output shaft.

2. A power operated wrench comprising in combination; a supporting framework, wheel means on said framework for allowing said framework to be moved longitudinally of a workpiece, drive means operatively connected to said wheel means for imparting rotary movement thereto, a drive head pivotally mounted upon said framework for swinging movement about a vertical axis, said drive head extending outwardly from one end of said framework, a drive motor mounted upon said framework, 2. horizontally disposed clutch shaft mounted upon said framework adjacent said drive motor, first and second selectively operable clutch assemblies positioned upon said clutch shaft, first and second drive means operatively connected between said drive motor and said first and second clutch assemblies respectively, said first clutch assembly being adapted to engage said clutch shaft with said first drive means and said second clutch assembly being adapted to engage said clutch shaft with said second drive means, said first drive means having a speed ratio different from the speed ratio of said second drive means, a reversing transmission operatively connected to said clutch shaft, a wrench output shaft rotatably mounted upon said drive head, coupling means connecting said wrench output shaft and reversing transmission, said coupling means including a universal joint, an enlarged manually operable member rigidly connected to said wrench output shaft for positioning said wrench output shaft with respect to a workpiece, a socket supporting member slidably mounted upon said wrench output shaft, means coupling said wrench output shaft and said socket supporting member for preventing relative rotational movement therebetween and a control lever means operatively connected between said wrench drive head and socket supporting member for sliding said socket supporting member axially of said wrench output shaft.

References Cited in the file of this patent UNITED STATES PATENTS 975,042 Jacobs Nov. 8, 1910 1,060,173 Edwards Apr. 29, 1913 1,189,754 Trenaman July 4, 1916 1,666,600 Jorden Apr. 17, 1928 1,734,475 Dedge Nov. 5, 1929 1,754,978 Buss Apr. 15, 1930 1,807,367 Woolery May 26, 1931 2,000,221 Dawson May 7, 1935 2,034,740 Brandt Mar. 24, 1936 2,228,589 Backes Jan. 14, 1941 2,433,959 Runkle Jan. 6, 1948 2,538,276 Shotfner Jan. 16, 1951 3,017,794 Pouget Jan. 23, 1962 FOREIGN PATENTS 1,152,231 France Sept. 2, 1957

Claims

1. A POWER OPERATED WRENCH COMPRISING IN COMBINATION; A SUPPORTING FRAMEWORK; A DRIVE MOTOR RIGIDLY MOUNTED UPON SAID SUPPORTING FRAMEWORK; A DRIVE HEAD PIVOTALLY CONNECTED TO ONE END OF SAID FRAMEWORK FOR MOVEMENT ABOUT A VERTICAL AXIS WITH RESPECT TO SAID FRAMEWORK, SAID DRIVE HEAD EXTENDING OUTWARDLY FROM SAID SUPPORTING FRAMEWORK; A VERTICALLY DISPOSED WRENCH OUTPUT SHAFT ROTATABLY MOUNTED WITHIN SAID DRIVE HEAD, A HORIZONTALLY DISPOSED SHAFT IN DRIVING ENGAGEMENT WITH SAID WRENCH OUTPUT SHAFT AND ROTATABLY MOUNTED WITHIN SAID WRENCH DRIVE HEAD; DRIVE MEANS ROTATABLY MOUNTED UPON SAID FRAMEWORK AND OPERATIVELY CONNECTED TO SAID DRIVE MOTOR FOR ROTATION THEREWITH; A FLEXIBLE COUPLING MEANS CONNECTED BETWEEN SAID DRIVE MEANS AND SAID HORIZONTALLY DISPOSED SHAFT; A SOCKET SUPPORTING MEMBER SLIDABLY MOUNTED UPON THE LOWER END OF SAID WRENCH OUTPUT SHAFT; MEANS COUPLING SAID SOCKET SUPPORTING MEMBER AND SAID WRENCH OUTPUT SHAFT FOR PREVENTING RELATIVE ROTATIONAL MOVEMENT THEREBETWEEN AND A CONTROL MEMBER OPERATIVELY CONNECTED BETWEEN SAID DRIVE HEAD AND SAID SOCKET SUPPORTING MEMBER FOR SLIDING SAID SOCKET SUPPORTING MEMBER AXIALLY OF SAID WRENCH OUTPUT SHAFT.