US3726506A

US3726506A - Hydraulic rod and pipe pusher-puller

Info

Publication number: US3726506A
Application number: US00163164A
Authority: US
Inventors: H Vanderwaal; D Vanderwaal
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-07-16
Filing date: 1971-07-16
Publication date: 1973-04-10
Anticipated expiration: 1990-04-10

Abstract

A rectangular horizontal frame that is set in a rectangular excavation between two vertical abutments at opposite ends has two large hydraulic cylinders disposed horizontally in parallel relation in the opposite sides of the frame with their piston rods connected to the opposite ends of a cross-head that is reciprocable on slides in the frame and carries at its middle a movable gripping jaw of elongated form to engage one side of a rod section to be pushed or pulled, while a fixed cooperating jaw on the cross-head engages the opposite side of the rod. The movable jaw is T-shaped and pivoted at the middle of the crossportion of the T to the cross-head on a vertical axis to grip, working in either direction for pushing or pulling, and is operated at the end of the leg of the T by a separate small hydraulic piston working in a cylinder pivoted at one end on one of the slides attached to the cross-head, thus making the gripping action a separately controllable thing from the heavy force applied in pushing or pulling the rod under hydraulic pressure using the main large pistons, thus avoiding damaging the rod by unnecessarily high gripping pressure. A separate manually controlled valve controls the gripping and releasing of the rod gripper from the same control stand where another manual control valve is provided to control the operation of the large pistons in the two large cylinders that move the cross-head back and forth in the pushing or pulling operation, thus speeding up the operation all around so that a new rod section can be inserted quickly in a pushing operation and one rod section after another can be removed speedily in a pulling operation. A manually operable cam cooperates with one end of a horizontally disposed hold-down plate at one end of the frame that is pivoted on a vertical axis at its other end to be swung into and out of operative position straddling the rod to apply a downward pressure on the leading end to direct it properly downwardly at an acute angle in relation to the horizontal plane of the frame to offset the tendency toward veering upwardly at the forward end.

Description

United States Patent 91 Vanderwaal et a].

[ 51 Apr. 10, 1973 [54] HYDRAULIC ROD AND PIPE PUSHER- PULLER [76] Inventors: Henry J. Vanderwaal; Dennis R. Vanderwaal, both of 9650 N. 2nd Street, Rockford, Ill.

[22 Filed: July 16, 1971 211 Appl. No.: 163,164

[52] U.S. CI. .;..254/29 [51] Int. Cl. ..E2lb 9/00 [58] Field of Search ..254/29 [56] References Cited UNITED STATES PATENTS 3,227,419 l/l966 Lackey ..254/29 R Primary Examiner-Othell M. Simpson Assistant Examiner-Robert C. Watson Att0rneyAndrew F. Wintercorn [5 7 ABSTRACT pulled, while a fixed cooperating jaw on the crosshead engages the opposite side of the rod. The movable jaw is T-shaped and pivoted at the middle of the cross-portion of the T to the cross-head on a vertical axis to grip, working in either direction for pushing or pulling, and is operated at the end of the leg of the T by a separate small hydraulic piston working in a cylinder pivoted at one end on one of the slides attached to the cross-head, thus making the gripping action a separately controllable thing from the heavy force applied in pushing or pulling the rod under hydraulic pressure using the main large pistons, thus avoiding damaging the rod by unnecessarily high gripping pressure. A separate manually controlled valve controls the gripping and releasing of the rod gripper from the same control stand where another manual control valve is provided to control the operation of the large pistons in the two large cylinders that move the cross-head back and forth in the pushing or pulling operation, thus speeding up the operation all around so that a new rod section can be inserted quickly in a pushing operation and one rod section after another can be removed speedily in a pulling operation. A manually operable cam cooperates with one end of a horizontally disposed hold-down plate at one end of the frame that is pivoted on a vertical axis at its other end to be swung into and out of operative position straddling the rod to apply a downward pressure on the leading end to direct it properly downwardly at an acute angle in relation to the horizontal plane of the frame to offset the tendency toward veering upwardly at the forward end.

15 Claims, 10 Drawing Figures PATENTED APR] 0 I975 SHEET 1 [1F 3 INVENTORS:

HENRYJ. VA/VDERWAAL DEN/W5 R VA/VDE WAAL W q Arrorney PATENTED APR 1 0 I975 SHEETEUFS IN l/E/V TORS. HENRY J. VAA/DERWAAL DENN/S :QVi/VDEQVAAL Attorney HYDRAULIC ROD AND PIPE PUSI-IER-PULLER This invention relates to a hydraulic rod and pipe pusher and puller unit designed to be set in an excavation alongside a roadway under which metal pipes, cable, conduit, plastic pipe, copper tubing, wire, etc., are to be pulled to avoid the necessity for tearing up a section of the roadway and interrupting traffic thereon during the rod pushing or pulling operation.

The principal object of our invention is to provide a unit, which by reason of the novel design of its hydraulic controls permits quicker gripping and releasing of the rod sections under hydraulic control, the gripping means being quickly reversible from the rod pushing to a rod pulling position, and the pressure applied in either position is separately controlled and entirely independent of the heavy force applied hydraulically in either pulling or pushing with the higher pressure pistons operating in the larger cylinders provided for those functions, so there is never any danger of damaging the rod sections. The manually operable control valves controlling the gripping'and releasing as well as the pushing and pulling operation being on a single control stand with their separate manually operable levers extending therefrom, the operator can easily speed up the pushing or pulling operation by proper timing of the gripping and releasing of the rod sections in relation to the reciprocation of the main pistons, so that there is much less time loss in each setup and takedown operation, and when this time saving is multiplied by the number of setup and takedown operations necessarily involved the number of man-hours and dollars saved in a given job becomes very impressive.

Another object is to provide a simple and yet very effective manually operable rod guide or hold-down member swingable into and out of operative position straddling the outgoing end of a rod section at one end of the frame where a manually rotatable cam riding on the free end of the member is arranged to force the same downwardly to steer the rod at an acute angle downwardly relative to the horizontal plane of the frame to precisely the degree necessary to offset the tendency for the leading end of the rod to veer upwardly in a rod pushing operation, the advantage in this simple feature being the ease with which the angle of the rod can be easily changed to the precise degree necessary with only a slight change in the position of the cam.

The invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of the hydraulic pusherpuller unit of our invention with a portion of the side wall of the rectangular frame broken away to better illustrate the construction;

FIG. 2 is a side view of the unit shown installed in an excavation and showing a spear-point applied to the leading end of a rod section that is being pushed forwardly through the ground under hydraulic pressure;

FIG. 3 is a plan view of the unit on an intermediate scale, with portions shown in section to better illustrate the construction;

FIG. 4 is a view similar to FIG. 3, but showing the cross-head in an extreme forward position, and indicating in dotted lines how another rod section can be applied onto the end of the previous one;

FIG. 5 is a longitudinal section on the line 5-5 of FIG. 3;

FIG. 6 is a cross-section on the line 66 of FIG. 3 looking forwardly from the cross-head and showing the cam operated hold-down plate straddling the forward end of the rod section and showing the manually operable hold-down cam;

FIG. 7 is a horizontal section on the line 7-7 of FIG. 6, showing the reversible hydraulically operated generally T-shaped rod gripper jaw, which is shown in full lines in the pushing position and in dotted lines in the reversed position for pulling, the same gripper jaw being equally effective in both positions for both purposes;

FIG. 8 is a perspective view of the two rod gripper jaws shown in disassembled spaced relation to better illustrate their construction, the one that is pivoted and reversible being shown above its support;

FIG. 9 is a cross-section on the line 99 of FIG. 3 showing the hold-down plate again and illustrating more clearly the cam operation thereof in forcing the leading end of the rod section downwardly at an acute angle to the horizontal plane of the frame to offset the tendency for its veering upwardly in the rod pushing operation, and

FIG. 10 is a perspective illustrating how neighboring rod sections are threadedly interconnected.

The same reference numerals are applied to corresponding parts throughout the views.

Referring to the drawings, and, initially, mainly to FIGS. 1 to 7, our hydraulic rod and pipe pusher-puller unit is designated generally by the reference numeral 11 and comprises a sturdy rectangular channel iron frame 12, the channel side members and end members of which interfit in telescoping relation, as seen best in FIG. 1, and are welded together at the four corners 13 where the flanges overlap. Projecting ears 14 on the top at opposite ends of the frame 12 receive hooks on the ends of chains or cables by means of which the unit 11 can be lowered into an excavation like that shown at 15 in FIG. 2 and later lifted out of it, large rectangular metallic plates 16 being shown as placed vertically between the ends of the frame 12 and the ends of the excavation 15 to assume the thrust in pipe pulling or rod pushing operations, and a rod section being indicated at 17 in FIG. 2 fitted on its outer end with a spear point 18 to facilitate its forward movement through the ground in a rod pushing operation. A reduced threaded end 19 is provided on one end of each rod section 17, as shown in FIG. 10, which permits threading a spear point fitting 18 thereon when a rod section 17 is the leading one of a series, and each rod section has an enlarged internally threaded coupling 20 formed on the other end in which the first mentioned reduced threaded end 19 of the following rod section 17 can be threaded as shown in FIG. 4 when the previous rod section has been pushed as far as it can be under hydraulic pressure and an extension section must be added. FIG. 3 shows the start of a rod pushing operation with the fixed jaw 21 and its cooperating pivoted jaw 22 gripping the rod section 17 between them near its rear end, the

jaws

21 and 22 being carried on a cross-head 23, which is in the form of a rectangular plate welded at its opposite ends to the lower flanges of channel slide members 24 that are slidable in the channels of the channel shaped side frame members 25 as guides. A large hole 26 is provided in the middle of the one end cross-piece of the frame through which the rod section 17 to be pushed into the ground is extended as seen in FIGS. 1, 2 and 4, ample clearance being left around the pipe 17, as best appears in FIGS. 1 and 9, to enable applying downward pressure on the forward end of the rod section by means of a hold-down plate 27 and rotary cam 28, as seen in FIGS. 6 and 9, the plate 27 straddling the rod section where an arcuate notch 29 is provided in the lower edge of the plate intermediate its ends, the plate being loosely hingedly mounted at one end, as at 30, on one of the channel side members 25 of the frame to permit swinging the plate 27 into or out of operative position easily, while the cam 28, which is pivoted on an eccentric mounting 31 on the inner side of the adjacent end cross-piece of the frame rides on the top of the plate 27 at its outer end for rotary adjustment by means of a crank 32 operable manually. A coiled tension spring 33 connected to the upper flange of the end cross-member of the frame and attached at its lower end to the plate 27 intermediate the ends thereof, urges the plate upwardly toward engagement with the cam 28, and the operator, who can set a carpenters level on the rod section 17 to check for inclination, can easily enough determine from the level the extent to which the rod section 17 should be forced downwardly at an acute angle relative to the horizontal plane of the frame to offset the tendency for the rod to veer upwardly when forced forwardly into the ground, only a slight change in the position of the cam 28 being enough usually to make whatever correction is necessary on the angle of the rod once the original setting of the cam 28 has predetermined the angle of movement of the rod, when, and if, there are indications that the angle of inclination is too much or not sufiicient.

Referring next to FIGS. 1, 3 to 5, and 7, there are two large long horizontal hydraulic cylinders 34 pivotally connected, as at 35 (FIG. at one end to the adjacent end cross-member of the frame and extending alongside the inner sides of the side members 25 in the channels thereof and having their piston rods 36 extending from the other ends and pivotally connected at their outer ends, as at 37, to the opposite end portions of the plate 23 to move the same with its guiding slides 24 lengthwise of the frame in either direction under hydraulic pressure. Flexible hose connections are indicated at 38 in FIGS. 1, 2 and 5 for delivery of oil under pressure to. either end of the cylinders 34 and the exhausting of oil from the other end under control 'of a valve 39 operable by means of a hand lever 40 to a forward or reverse position. The source of oil under pressure may be either a separate oil pump unit stationed nearby alongside the excavation or it may be in the form of take-off lines from a nearby backhoe or other earth moving implement equipped with hydraulic pump equipment for power lift operation of its shovel, for example, the input and return lines 41 extending from the valve 39, as shown in FIGS. 1 and 2. The valve 39 is carried on a control panel mounted about waisthigh horizontally on standards 43 suitably secured to the frame of the unit 11 so as to arrange the control lever 40 at a convenient elevation for handiest operation by an operator standing in the excavation 15 alongside the unit 11 or sitting on the ground and rest- I ing his feet on the frame 12 of the unit 11, whichever is handiest and most comfortable while giving the operator a good view of the entire operation for best control. The other control lever 44 operates the valve 45, which 'has flexible hose connections 46 with opposite ends of a smaller cylinder 47 that is pivotally connected, as at 48, at one end to the adjacent slide 24 to move the piston rod 49 in either direction to operate the pivoted jaw 22 accordingly to grip or release the rod section 17 from either of its gripping positions, the one shown in full lines in FIG. 7 being for rod pushing, while that shown in dotted lines in the same figure is for rod and pipe pulling. The pivoted jaw 22 is generally T-shaped and has V-

notches

50 and 51 provided in opposite ends of the cross-portion 52, in either of which one side of the rod section 17 can be engaged under sufficient hydraulic pressure applied to the lever 53, to which the piston rod 49 is pivotally connected, as at 54, to grip the rod section between the

jaws

21 and 22 with sufficient force to do a good job of rod pushing or pipe pulling without, on the other hand, giving rise to any danger of damaging the rods by unnecessarily heavy pressure. Here the gripping of the rod section hydraulically is entirely independent of the pushing and pulling function of the cylinders 34 and piston rods 36. A V- groove extends lengthwise of the fixed jaw 21, as shown at 55, to provide the desired length of engagement with one side of the rod section opposite the movable jaw 22, which, as best appears in FIG. 7, is pivoted at 56 at the middle of the cross-portion of the T, this portion of the jaw being housed between the plate 23 and a companion plate 57 suitably bolted to the plate 23 with spacer blocks 58 disposed between the two parts, leaving adequate operating clearance for the pivoted jaw In operation, when the unit is operating as a rod pusher, the pivoted gripper jaw 22 is disposed, as shown in full lines in FIG. 7, with the piston rod 49 pulling on the arm 53 to cause tight engagement of the jaw 22 with the rod section 17 clamping the same between the

jaws

21 and 22. Then, when the piston rods 36 have moved forward under hydraulic pressure to the limit position, shown in FIG. 4, it is necessary to operate the control lever 44 first to release the jaw 23 before control lever 40 is operated to return the piston rods 36 to the retracted position shown in FIG. 3, whereupon, after insertion of another length of rod section 17, as shown in dot and dash lines in FIG. 4, the

jaws

21 and 22 can be closed again by operation of the control lever 44, and the piston rods 36 can be moved forwardly again under hydraulic pressure in cylinders 34 by operating the lever 40 forwardly, and, as soon as the rods 36 have been moved forwardly as far as they can go, control lever 44 will be moved to the rear to release the jaw 22 and permit the rods 36 to be retracted by rearward movement of control lever 40, when the jaw 22 can be operated again to gripping position by forward movement of lever 44 and the rods 36 operated again on their forward stroke by forward movement of lever 40. It is obvious from FIGS. 3 and 4 that each rod section 17 is of a length sufficient to require two full movements of the piston rods 36 to push a given rod section 17 forward its full length, so it can be appreciated how important it is that the opera tion of the jaw 22 under separate hydraulic control with lever 44 speeds up the operation considerably in addition to the equally, if not more, important feature of making the gripping of the rod section with jaw 22 entirely independent of the heavy force applied with piston rods 36 in cylinders 34 in pushing the rod forward without any danger of damage to the rod and yet insuring sufficient gripping action to avoid danger of slippage. The only difference in a rod pulling operation, when the jaw 22 is in the dotted line position, shown in FIG. 7, is that under those conditions the rod 49 pushes the jaw 22 into gripping engagement with the rod section instead of pulling it into engagement, as in the pushing operation. An operator quickly learns how to coordinate and time the operation of the control levers 40 and 44 so that there is very little or no time lost, and that, of course, is very important when you consider the total number of operations involved in a given rod pushing or pulling job. The man-hours saved with this speedier control makes a large saving in overall cost. The elevated support 42 for the valve controls is not only handier but safer, as there is always the danger of cave-ins, and by elevating the controls to waist level, this makes for safety by keeping the operator in an upright position where he always has a good view of the entire operation. The simplicity also with which the operator can steer the rod at the correct angle by means of plate 27 and cam 28 is a very important advantage of the present construction. Once the overall length of rod sections necessary to do a job has been pushed forward, it is a simple matter then to pull pipe, cable, conduit, tubing, plastic pipe, wire, etc., by pulling the same, using the rod sections 17 for this purpose, as is well known in this art.

It is believed the foregoing description conveys a good understanding of the objects and advantages of our invention. While a preferred embodiment of the invention has been illustrated and described, this is only for the purpose of illustration, and it is to be understood that various modifications in structure will occur to a person skilled in this art.

We claim:

1. A rod and pipe pushing and pulling device comprising a frame, a cross-head reciprocable in said frame, hydraulic cylinder means mounted in said frame having piston means reciprocable therein connected with said cross-head to move the same under hydraulic pressure in either direction, a source of hydraulic fluid pressure, manually controlled valve means for delivering hydraulic fluid under pressure from said source to either end of said cylinder means while exhausting fluid to said source from the other end, rod gripping means on said cross-head including a fixed jaw parallel to the rod to engage a rod from one side and an oscillatable jaw to engage the rod edgewise in angular relationship thereto from the opposite side, hydraulic piston and cylinder means of smaller diameter than the first mentioned piston and cylinder means operatively connected with said movable jaw to operate the same independently of the first mentioned piston and cylinder means, and manually operable valve means for delivering hydraulic fluid from said hydraulic fluid source under pressure to either end of the last mentioned piston and cylinder means.

3. A device as set forth in claim 1, wherein the oscillatable jaw is generally T-shaped and pivoted at the middle of the cross-portion of the T on said cross-head so that in one position of oscillation one end of the cross-portion engages the rod at an acute angle in one direction for pushing, but in another position of oscillation the other end of the cross-portion engages the rod at an acute angle in the opposite direction for pulling, the leg of the T being pivotally connected with the last mentioned hydraulic piston and cylinder means to oscillate the movable jaw from one position to the other and apply a pull on the leg of the T in a pushing operation and apply a pushing force on the leg of the T in a pulling operation.

4. A rod and pipe pushing and pulling device comprising a frame, a cross-head reciprocable in said frame, hydraulic cylinder means mounted in said frame having piston means reciprocable therein connected with said cross-head to move the same under hydraulic pressure in either direction, a source of hydraulic fluid pressure, manually controlled ,valve means for delivering hydraulic fluid under pressure from said source to either end of said cylinder means while exhausting fluid to said source from the other end, hydraulically operable rod gripping means operable independently of the first mentioned piston and cylinder means and swingable from one angular position relative to the rod for a rod pushing operation to an opposite angular position relative to the rod for a rod pulling operation, piston and cylinder means operatively connected with said rod gripping means, and a manually controlled valve means for delivering hydraulic fluid under pressure from said pressure source to either end of the last mentioned piston and cylinder means to grip or release the rod.

5. A device as set forth in claim 4, in which the rod gripping means includes a pivoted member, which, when oscillated to one position, is disposed for a rod pushing operation, but, when oscillated to another position, is disposed in a rod pulling operation, the last mentioned piston and cylinder means exerting a pull on the pivoted member in one of said operations and a push on said member in the other operation.

6. A rod and pipe pushing and pulling device comprising a frame having an end wall provided with an opening for extension therethrough of a rod horizontally from said frame in a rod pushing operation, means in said frame for pushing the rod forwardly, and means for exerting a downward pressure on a rodto direct it downwardly to an acute angle to the horizontal in a rod pushing operation comprising a substantially horizontal cross-member bearing on top of said rod near said end wall of said frame, and manually operable cam means rotatable relative to said end wall and serving to force said cross-member downwardly to a predetermined extent to secure downward inclination of the forward end of the rod in the rod pushing operation.

7. A device as set forth in claim 6, wherein the crossmember has a notch provided therein on the underside receiving the rod to guide the same in its forward movement.

8. A device as set forth in claim 6, in which the crossmember is loosely, pivotally mounted at one end in said frame and has a notch provided therein intermediate the ends thereof on the bottom to serve as a guide for the rod, the cam means bearing on the outer end of said cross-member.

9. A device as set forth in claim 6, in which the crossmember is loosely, pivotally mounted at one end in said frame and has a notch provided therein intermediate the ends thereof on the bottom to serve as a guide for the rod, the cam means bearing on the outer end of said cross-member, and spring means suspending said crossmember relative to said frame keeping the crossmember biased toward said cam means.

10. A rod and pipe pushing and pulling device comprising an elongated horizontal frame having opposed channel side members and channel end members in crosswise telescoping relationship to the opposite ends of the side members and secured thereto, channel slide members slidable in the channels of the side members in nesting relationship thereto, a cross-head plate of rectangular form mounted on the bottom flanges of the slide members at its opposite ends and secured thereto, a pair of parallel hydraulic cylinders housed in said frame in the channels of the side members and secured at one end to one end member of said frame and having piston rods extending from the other end and connected to the cross-head plate at its opposite ends for pushing or pulling said plate with said slide members in said frame, rod gripping means on said cross-head plate at the middle thereof, a source of hydraulic fluid under pressure, and manually operable valve means for delivering fluid under pressure from said source to one end of said cylinders while draining fluid to said source from the other end thereof.

1 1. A device as set forth in claim 10, including a control panel mounted at a fixed elevation relative to said frame and carrying the manually controlled valve means thereon while a hand lever for operating said valve means extends from said control panel for convenient operation.

12. A device as set'forth in claim 10, including a control panel mounted at a fixed elevation relative to said frame and carrying the manually controlled valve means thereon while 'a hand lever for operating said valve means extends from said control panel for convenient operation, the valve means including another valve for delivering fluid under pressure to another cylinder at one end while exhausting fluid from the other end of said cylinder, the last mentioned cylinder being a smaller one pivotally mounted at one end on one of said channel slide members while the piston rod extending from the other of said cylinder has pivotal connection with the rod gripping means, the control panel having a second lever extending therefrom for manual operation of the additional valve for controlling the rod gripping means independently of the operation of the pistons in the other cylinders functioning to apply pushing or pulling force to the rod.

13. A device as set forth in claim 10, including upwardly projecting ears on the upper flanges of the end channels, these ears having openings provided therein for connection therewith of chains or cables for raising or lowering the frame out of or into an excavation.

14. A device as set forth in claim 10, wherein the rod gripping means includes a T-shaped gripping jaw which when oscillated to one extreme angular position relative to the rod serves for gripping the rod in a rod pushing operation, but, when oscillated in the other direction to an opposite extreme angular position relative to the rod serves to grip the rod in a rod pulling operation, the jaw in one position being pulled by the piston rod and in the other position being pushed by the piston rod to apply the necessary gripping action, and in each position being disposed at an acute angle relative to the rod for wedging engagement therewith in either operation.

15. A device as set forth in claim 10, wherein the channel end member at one end of said frame has an enlarged opening provided therein in relation to the size of the rod extending horizontally forwardly therethrough from the frame from the rod gripping means, the device including a hold-down plate loosely pivoted at one end relative to one of the side members of said frame and straddling the rod to apply downward pressure on the rod, and a cam rotatable relative to the channel end member and bearing on the outer end of said hold-down plate to apply downward pressure on the rod to the extent necessary for a predetermined downward inclination of the rod relative to the horizontal plane of the frame.

Claims

2. A device as set forth in claim 1, wherein the two manual controls for the two manually operable means are carried on a single elevated support in close proximity to one another for speedy operation by a single operator.

4. A rod and pipe pushing and pulling device comprising a frame, a cross-head reciprocable in said frame, hydraulic cylinder means mounted in said frame having piston means reciprocable therein connected with said cross-head to move the same under hydraulic pressure in either direction, a source of hydraulic fluid pressure, manually controlled valve means for delivering hydraulic fluid under pressure from said source to either end of said cylinder means while exhausting fluid to said source from the other end, hydraulically operable rod gripping means operable independently of the first mentioned piston and cylinder means and swingable from one angular position relative to the rod for a rod pushing operation to an opposite angular position relative to the rod for a rod pulling operation, piston and cylinder means operatively connected with said rod gripping means, and a manually controlled valve means for delivering hydraulic fluid under pressure from said pressure source to either end of the last mentioned piston and cylinder means to grip or release the rod.

6. A rod and pipe pushing and pulling device comprising a frame having an end wall provided with an opening for extension therethrough of a rod horizontally from said frame in a rod pushing operation, means in said frame for pushing the rod forwardly, and means for exerting a downward pressure on a rod to direct it downwardly to an acute angle to the horizontal in a rod pushing operation comprising a substantially horizontal cross-member bearing on top of said rod near said end wall of said frame, and manually operable cam means rotatable relative to said end wall and serving to force said cross-member downwardly to a predetermined extent to secure downward inclination of the forward end of the rod in the rod pushing operation.

7. A device as set forth in claim 6, wherein the cross-member has a notch provided therein on the underside receiving the rod to guide the same in its forward movement.

8. A device as set forth in claim 6, in which the cross-member is loosely, pivotally mounted at one end in said frame and has a notch provided therein intermediate the ends thereof on the bottom to serve as a guide for the rod, the cam means bearing on the outer end of said cross-member.

9. A device as set forth in claim 6, in which the cross-member is loosely, pivotally mounted at one end in said frame and has a notch provided therein intermediate the ends thereof on the bottom to serve as a guide for the rod, the cam means bearing on the outer end of said cross-member, and spring means suspending said cross-member relative to said frame keeping the cross-member biased toward said cam means.

11. A device as set forth in claim 10, including a control panel mounted at a fixed elevation relative to said frame and carrying the manually controlled valve means thereon while a hand lever for operating said valve means extends from said control panel for convenient operation.

12. A device as set forth in claim 10, including a control panel mounted at a fixed elevation relative to said frame and carrying the manually controlled valve means thereon while a hand lever for operating said valve means extends from said control panel for convenient operation, the valve means including another valve for delivering fluid under pressure to another cylinder at one end while exhausting fluid from the other end of said cylinder, the last mentioned cylinder being a smaller one pivotally mounted at one end on one of said channel slide members while the piston rod extending from the other of said cylinder has pivotal connection with the rod gripping means, the control panel having a second lever extending therefrom for manual operation of the additional valve for controlling the rod gripping means independently of the operation of the pistons in the other cylinders functioning to apply pushing or pulling force to the rod.