US3384186A

US3384186A - Mobile hydraulic hammer

Info

Publication number: US3384186A
Application number: US522715A
Authority: US
Inventors: Dean E Broderson; Jr Herbert W Gronemeyer; Frank D Freudenthal
Original assignee: R O PRODUCTS Inc
Current assignee: R O PRODUCTS Inc
Priority date: 1966-01-24
Filing date: 1966-01-24
Publication date: 1968-05-21
Anticipated expiration: 1985-05-21

Description

y 21, 1968 D. E. BRODE RSON ETAL 3,384,186

MOBILE HYDRAULIC HAMMER 7 Sheets-Sheet 1 Filed Jan. 24, 1966 I N VE NTORS aFEW/v ,5. 560275660 May 21, 1968 D. E. BRODERSON ETAL 3,384,185

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MOBILE HYDRAULIC HAMMER Filed Jan. 24, 1966 '7 Sheets-Sheet '7 BYZ ATTORNEYS United States Patent 3,384,186 MOBILE HYDRAULIC HAMMER Dean E. Broderson, Kansas City, Mo., and Herbert W. Gronemeyer, Jr., Leawood, and Frank D. Freudenthal, Overland Park, Kans., assignors to R 0 Products, Inc., Olathe, Kans., a corporation of Kansas Filed Jan. 24, 1966, Ser. No. 522,715 11 Claims. (Cl. 173-24) ABSTRACT OF THE DISCLOSURE An improved mobile hydraulic hammer apparatus is described, and the apparatus includes a separately mounted hydraulic actuating and control means which operates a hammer within a tower. Means are provided for traversing the tower and hammer from side to side of the apparatus, and the hydraulic actuating and control means for the hammer is mounted in a housing which can remain fixed relative to traversing movements of the tower so that there is no interference with hydraulic hoses and other devices associated with the actuating and control means. Also, the apparatus includes means for tilting a body of a vehicle relative to the wheels of the vehicle so that the tower and hammer can be tilted relative to the vehicle, and a steering and seating assembly of the apparatus may be rotatable about a vertical axis.

This invention relates to mobile hydraulic hammer apparatus and particularly to improved hydraulic hammer devices suitable for breaking up pavement and for similar hammering requirements.

Mobile hammer devices are generally known in the art and such devices usually include a weighted hammer means which can be raised and then dropped onto objects which are to be broken up or compacted. The hammer means is carried on a vehicle which can be wheeled from place to place, and in the conventional construction, hydraulic power may be used to raise the hammer in a tower for dropping the hammer in a free fall hammering action. Such prior devices have been used for breaking up pavement and for earth compaction where highways or driveways are being recovered or rebuilt, or in connection with ditching or trenching operations. However, the prior art constructions have had certain'limitations in their initial and maintenance costs, and this has restricted their use and acceptance for a veriety of job needs.

The present invention provides for a self-propelled unit which includes a hammer means mounted and actuated in a novel manner, and the unit also includes earthworking tools other features which permit it to be adapted to a variety of job requirements. The self-propelled unit of this invention is designed to handle jobs requiring the breaking of pavement, the cutting of asphalt, the cutting of frozen earth, and the tamping of backfill earth in road and underground utility projects.

The hammer means of the present invention is mounted for reciprocation in a movable tower which is carried at one end of the self-propelled vehicle. The hammer means is lifted and dropped through the use of hydraulic actuation and control devices, and a novel means is provided for actuating the hammer while at the same time protecting the hydraulic devices associated with it. The tower which supports the hammer is mounted at one end of the vehicle so that it can be traversed back and forth in various positions relative to the vehicle chassis. In this manner, the tower can be moved to a desired location for dropping the weighted hammer or other tool at a specified point transversely of the position of the vehicle. One of the important features of the present invention resides in the mounting means and actuating means for the hammer whereby there is no interference with hye draulic control functions when the tower is transversed from one position to another relative to the remainder of the vehicle. Prior constructions have required the use of hydraulic conduits between the tower structure and the vehicle itself for conveying hydraulic fluid to a means for actuating and controlling the movement of the hammer within the tower. The present invention eliminates a requirement for costly hydraulic hoses running for considerable lengths from the vehicle to the tower structure (which hoses move during traverse and tend to wear because of this repeated motion and vibration, and which hoses tend to obscure the operators view of working area), and the hoses of the present invention are not interfered with or interrupted in their operation by transverse movements of the tower relative to the vehicle. In addition to the improved control system just described, there is provided a means for hydraulically and automatically controlling the height to which the hammer is lifted and the dwell time. between the time the hammer is released for the hammering action and the time its elevation commences. A further feature of the hammer means and tower structure of this invention resides in the ability to lower the tower together with the hammer means into a horizontal plane, and this position is used when the unit is being transported for relatively long distances from one job site to another. With the apparatus of this invention, the tower can be stowed on either side of the operator for improved balance of the vehicle, as desired. Also, the hammer means can be retained in any position along the length of the tower when the tower is lowered to a horizontal plane, and this permits the use of the hammer and its associated weight to balance the entire unit for other functions, such as grading and filling operations.

The self-propelled vehicle which is a part of the present invention includes driving means for propelling the vehicle at highway speeds for rapid movement from one job location to another or at creeping speeds for moving the vehicle slowly during a hammering operation at a particular job site. The creeping speed is related to the rate of hammering and a provision is made for hydraulically propelling the unit at creeping speeds, whereby shocks and vibrations from the hammering action will be absorbed and not transmitted to the transmission of the vehicle. The mobile vehicle is constructed so that the entire chassis, including the tower and hammer means, can be tilted about a longitudinal axis of the vehicle and relative to the position of the wheels of the vehicle. This latter feature permits the vehicle to work on grades while maintaining a vertical operation position for the operator, the tower and the movement of the weighted hammer within the tower. As a result, there is minimum wear on the guideways of the tower within which the hammer is reciprocated, and a better hammering action is attained by the vertical fall of the hammering tool for all types of terrain. The vehicle also includes a novel seating and steering construction which allows the operator to rotate the seat together with all steering controls within a degree circumference. This feature permits the operator to place himself and the steering mechanism in a position to drive the unit in the same manner as he would a truck; or he can reverse his position 180 degrees for controlling and viewing a hammer action while maintaining control of the steering mechanism.

These and other features of this invention will become more apparent from the more detailed discussion which follows and in that discussion reference will be made to the accompanying drawings in which:

FIGURE 1 is a side elevational view of the hammering vehicle of this invention, showing the hammer tower in a raised operative position;

FIGURE 2 is a back elevational view of a traversing mechanism for moving the hammer tower transversely from side to side of the vehicle as seen from line 22 of FIGURE 1;

FIGURE 3 is a detail section of the traversing mechanism showing a motor means connected to a drive chain;

FIGURE 4 is a cross sectional view taken at line 4-4 of FIGURE 2 and illustrating the guideways associated with the traversing mechanism for the tower;

FIGURE 5 is a partial elevational view showing the tower structure together with a cable and sheave system for raising and dropping a hammer means contained within the tower;

FIGURE 6 is a top plan view of a cable and sheave system for actuating the hammer means;

FIGURE 7 is a detailed view taken at line 77 of FIGURE 5 and showing a linking means for one end of the hammer lifting cable;

FIGURE 8 illustrates a detailed view taken at line 8-8 of FIGURE 5, and showing a connecting means for a second end of the hammer lifting cable;

FIGURE 9 is a cross section taken at line 99 of FIGURE 5 and showing a detail of the tower structure as related to a weighted portion of the hammer means;

FIGURE 10 is a schematic layout of a hydraulic control system for actuating the hammer means;

FIGURE 11 is an elevational view showing a hydraulic driving means for bypassing a conventional driving means associated with the self-propelled vehicle of this invention;

FIGURE 12 is a front elevational view showing a tilting mechanism for tilting the vehicle chassis relative to the vehicle wheels; and

FIGURE 13 illustrates a novel seating and steering assembly which can be rotated as a unit for ease of operation of the vehicle.

The power hammer unit of this invention is illustrated in its basic form in FIGURE 1'. The unit includes a vehicle 10 mounted on wheels, and an engine is provided for propelling the vehicle over the ground. Mounted at one end of the vehicle is a tower 12 which serves as a support frame and guide for reciprocations of a hammer means 14. The tower is pivotally mounted on a horizontal axis 16 so that it can be moved from an inoperative horizontal position (dotted lines) to the operative vertical position, as shown. A hydraulic piston and cylinder means 18 is interconnected between a portion of the vehicle 10 and structure associated with the tower 12 so that extension and retraction of the piston within the cylinder will serve to lower and raise the tower 12 about its pivotal axis 16. Suitable control devices and hydraulic conduits are provided for controlling a flow of fluid into the hydraulic piston and cylinder means 18 and these control devices are of any well-known construction for actuating such a hydraulic device.

The hammer means 14 includes a relatively large weighted portion 20 which is guided for reciprocating movements within the upright guides 22 of the tower 12. The hammer means also includes a tool or working portion 24 which is attached at a lower end of the weighted portion 2 0. Thus, the hammer means can be lifted to a desired height in the vertically positioned tower, and then dropped so that the weighted portion 20 will drive the working element 24 into pavement or whatever object is being hammered. The hammer means 14 is raised to its upper positions within the tower 12 by a novel sheave and cable system which includes means for hydraulically extending and retracting a cable. The hydraulic means for controlling the cable is contained entirely within a part of the tower structure which is never moved while the tower and its hammer are in operation, and a more detailed description of the hydraulic actuating system will follow at a later point of this application.

Referring to FIGURES 1 and 2, it can be seen that the tower 12 is mounted for movement transversely across the end of the vehicle 10 by a chain and sprocket means 26 which is controlled independently of the cable and sheave means mentioned above. In prior constructions, provision has been made to move a tower transversely of a vehicle, but the actuating mechanisms for such tower constructions required that any associated hydraulic conduits and devices for lifting the hammer move with transverse movements of the tower. As a result, there was considerable wear and binding on the hydraulic conduits, and it was necessary to use long lines for conveying the hydraulic fluid to a point of actuation on the tower for the hammer means associated therewith. The present invention permits full traversing movements of the tower structure relative to the vehicle without interfering with or binding any hydraulic conduits used for lifting and releasing the hammer means within the tower. This improved arrangement is a result of providing a short hydraulic conduit 28 which does not move with the traversing movements of the tower but which does provide all hydraulic fluid flow which is necessary to raise and release the hammer. Thus, the present structure eliminates the need for costly long length hydraulic conduits running between the vehicle and the tower, as has been typical in prior constructions. Further, the present construction allows free movement of the tower transversely across the end of the vehicle without interfering with the separate functions which raise and release the hammer means 14. The chain and sprocket means 26 for moving the tower transversely of the vehicle are illustrated in detail in FIGURES 2 and 3. A motor means 30 is connected to drive a sprocket wheel when it is desired to move the tower from one of its upright positions to another across the end of the vehicle. The motor may be of any conventional design and may utilize electric energy or hydraulic fluid for its operation. Actuation of the motor 30 causes a movement of the chain means 32 which is connected to a portion of the tower structure at 33 so as to move the tower along with the movement of the chain. The tower is mounted for transverse movements on a pair of spaced guideways 34 and the guideways are illustrated in detail in FIGURE 4. The guideways are shown in the form of hollow metal rails having square cross-sections and these rails contact mating surfaces 35 contained within a portion of the tower structure. Graphite impregnated phenolic bearing plates 36 are aflixed to the mating surfaces 35 for reducing friction between the guideways and the mating surface of the tower. In this manner, the entire tower can be traversed back and forth across the end of the vehicle along the guideways 34, and all movements of the tower are precise and smooth because of the novel guideway structure together with its provision of graphite impregnated phenolic bearing plates 36.

The guideways 34 together with the chain and sprocket system 26 are contained within a housing structure 38 mounted at the end of the vehicle for supporting the tower 12. The housing structure is pivotally mounted at the above mentioned axis 16 so that the entire housing together with all of its contained structures, including the tower, are moved between vertical and horizontal positions upon actuation of the hydraulic cylinder 18. An upper portion of the housing structure 38 is constructed to contain the lifting and releasing means for the hammer means which operates within the tower. The lifting and releasing means comprises a cable and sheave system which can be hydraulically extended to operate the cable around a plurality of sheaves in such a way that the hammer means is lifted to one of its upper positions in the tower 12. As seen in FIGURES 5 and 6,

sheave members

40 and 42 are contained at opposite ends and in the upper portion of the housing 38, and a hydraulic cylinder 44 is interposed between the sheaves for moving one of the sheave members relative to the other. The sheave member 40 may be mounted in a permanent position at one end of the upper housing structure, while the sheave member 42 may be mounted to be moved toward and away from the sheave member 40. In the preferred embodiment, a hydraulic cylinder 44 is installed between the

sheaves

40 and 42, and an arm member 46 extending from the cylinder can be actuated to move the sheave member 42 away from the sheave 40. This movement causes a movement of the cable 48 about the plurality of sheaves associated with each sheave member, and the hammer means 14 is lifted in accordance with the extension movements of the cable 48. Of course, the number and arrangement of individual sheaves may be modified to accommodate desired mechanical advantages for the system.

Looking to the detailed illustration of FIGURE 5, it can be seen that one end of the cable 48 is attached at 50 to the weighted portion of the hammer means. An opposite end of the cable 48 is connected to a link 52 mounted on the tower structure, and thus for all transverse movements of the tower there is a relative movement of the cable 48 about the large pulley 54 and ultimately to the end of the cable which is attached to the hammer means. This relative movement of the cable with all transverse movements of the tower provides for a compensation in the length of cable which is supporting the hammer means 14, and in this manner, the hammer is maintained at a substantially constant level for all transverse movements of the tower. The advantage in this arrangement resides in maintaining the hammer at a preselected level for continued operation irrespective of any transverse movement of the tower position.

FIGURE 7 illustrates a detail of the link structure 52 and its relationship to the tower 12 and to a guide pulley 56. The guide pulley is mounted outside of the path of movement for the hammer means, and the cable 48 extends upwardly along the length of the tower and over an upper pulley 58 for supporting and moving the hammer means 14. FIGURE 8 illustrates in detail a connection means for coupling the upper end 50 of the cable 48 to the weighted portion 20 of the hammer means. It can be seen that the cable is looped over a wedge 60 in the weighted portion 20, and is then held in place by the clamping force of the wedging action. From this clamped position, the cable then passed downwardly and upwardly for supporting the entire weight of the hammer means, as shown in FIGURE 5. FIGURE 9 shows in detail a cross section through the upright tower guides 22, and these guides are formed from a metal extrusion, or a combination of angular elements, to provide the con figuration shown. The weighed portion 20 is fitted between the spaced upright guides 22 for an up and down reciprocation between the guides. As illustrated in FIG- URE 9, the weighted portion 20 of the hammer means includes slotted portions at its outer margins for embracing the guide surfaces of the tower guides 22. Thus, the hammer means can be lifted to an upper position within the tower framework and then released for a free fall which drives the working tool portion 24 into an object which is to be hammered. The hammer means 14 is lifted in the tower by the application of hydraulic force to the cylinder 44, as discussed above, and the hammer is then released for a free fall by a control arrangement which permits the dumping of hydraulic fluid from the cylinder 44 at a desired time.

A hydraulic control system for automatically controlling the lifting and dropping of the hammer means 14 is illustrated in FIGURE 10. This control system includes an automatic control and also a manual control for lifting and releasing the hammer means at desired time intervals. The hydraulic cylinder means 44, which actuates the

sheaves

40 and 42, is shown in the lower left-hand corner of the schematic layout of the hydraulic system. A pumping means 64 is connected to a source of power for being driven and for pumping hydraulic fluid through the system. From the pump means 64 fluid is caused to flow through the line 66 and through a manually operated valve 68 which is normally set to permit a passage of fluid from the line 66 and into a line 70 when it is desired to raise the hammer means to an upper position in the tower. A solenoid valve means 72 is interposed between the line 70 and the line 28 which leads into the hydraulic cylinder 44. It will be recalled that the line 28 is in the form of a short flexible hose which is the only requirement for such a hose in the system of this invention". When the hammer is being raised, by an extension of the arm member 46 outwardly (in the direction of the arrow) away from the cylinder 44, it is necessary that the valve means 72 be closed to line 82 to permit a pumping of hydraulic fluid into the cylinder 44. The solenoid valve 72 is of a conventional construction and is automatically controlled by electric switching means which are shown schematically at 76. Suitable connections are provided between the switching means and the electrically operated solenoid valve 72 so that the valve can be actuated to a first position which blocks the flow of oil to line 82, thus forcing pressurized fluid into the cylinder 44, or to a second position which permits the dumping of fluid out from the cylinder 44 through line 82. The automatic switching means 76 includes controls for determining the length of time the valve is held in a position which forces a flow of fluid to the cylinder 44 and for the length of time that the valve is moved to a position which dumps fluid from the cylinder 44. These two separate controls are shown respectively at 78 and 80. In the preferred control arrangement, the control 78 determines the length of time that current is olf relative to the solenoid operated valve means 72. When the current is off, the valve 72 is set to permit a pumping of fluid into the hydraulic cylinder 44 through the lines 66, 70, and 28. By controlling the length of time that fluid can be pumped into the cylinder 44, there is also a control of the extent of movement of the sheave 42 away from the sheave 40. This control determines the maximum height to which the hammer is lifted within the tower 12, and it is important to be able to control the height from which the hammer can be dropped for any particular job requirement. When the hammer reaches the predetermined height, electric current is caused to actuate the solenoid valve means 72 into a position which permits the dumping of hydraulic fluid out of the cylinder by way of the line 28 together with the line 82. At the same time, the pumping of fluid is continued through the valve means 72 and through line 82 to the reservoir and it will be appreciated that once the line 82 is opened for dumping fluid, the weight of the raised hammer and its force upon the cable means 48 will cause a return movement of the arm 46 into the cylinder 44. A piston means of conventional design is contained within the cylinder 44 and aflixed to the end of the arm 46, and this piston means dumps hydraulic fluid out of the cylinder 44 and back into a reservoir contained within the system. The control switch determines the amount of dwell time that remains between the time the hammer is released for hammering action and the time that its lifting is commenced. This control feature permits a control of the rate of a hammering operation, and thus, the system permits an automatic repetition of preset hammering cycle in accordance with the positions of the switches 78 and 80. A manually operated control arm 84 provides for manually turning a valve device 68 to a position which stops further pumping of hydraulic fluid through the line 70 and into the hydraulic cylinder 44. The manual control arm 84 opens a dump line 86 which returns to the reservoir of the system, and when the control lever is moved in the direction of the arrow, the line 86 is opened for a dumping of hydraulic fluid from the cylinder 44 through the lines 28 and 70. This dumping action can be made to take place even though the automatic control system 76 is in operation, and this permits the operator to override the automatic operation of the hammer device.

A further feature of this invention is illustrated in FIG- URE 11, and this feature is concerned with a driving means for hydraulically driving the vehicle during hammering operations, while taking the normal transmission means out of operation. A vehicle engine 88 normally drives the vehicle through a transmission means which is coupled to the rear wheels of the vehicle through a two-speed transfer case 92. This normal drive train for highway travel includes the drive shaft and coupling members 94 and 96, and the drive train provides for a direct drive to the rear wheels through the usual transmission 90. When it is desired to use the vehicle in a harnmering operation and to drive the vehicle at a very slow creeping speed which is correlated to the rate of hammering, a means is provided which disengages the usual transmission 90 in the drive train, while engaging a hydraulic driving means. The advantage in driving the vehicle at slow speeds by a hydraulically operated means resides in the removal from the transmission 90 of the vibrations and severe stresses normally caused 'by the hammering action. The hydraulic driving means includes a pump device 98 which pumps hydraulic fluid through the line 100 in the direction of the arrows. Ultimately, the flow of hydraulic fluid is caused to operate the hydraulic motor means 102 which is of any conventional construction, and supply and return lines 104 and 106 are provided to and from the hydraulic motor. Interposed between the pump means 98 and the hydraulic motor 102 is a valve control device 108 which includes manually operated levers for controlling the flow of fluid through the valve 108 and to the hydraulic motor. When the hydraulic motor 102 is operated, a gear train within a power take-off device 110 is rotated for driving the drive shaft 96. When this driving means is being used to drive the gear train, the usual transmission 90 is placed in neutral so that there is no driving connection between the engine 88 and the two-speed transfer case 92. A manually operated lever 112 may be provided for engaging and disengaging the gear train within the power take-off device, and in the position shown the gear train is engaged, but would be disengaged upon movement of the lever 11?. to the dotted line position. A separate control lever 114 is provided for engaging and disengaging a separate power take-off device 116 which is associated with the pump means 98. This means can be used for bringing the pump no operation, and may be interconnected to the engine for an operation of the pump 98. When a hammering operation is completed and it is desired to move the vehicle to another job site, the hydraulic motor means 102 can be disengaged from operation, and the normal drive train through the transmission 98) and the drive shafts 94 and 96 can be re-established.

In addition to the driving control of the vehicle, there is provided a means for tilting the entire vehicle about a longitudinal axis, as illustrated in FIGURE 12. The vehicle chassis is pivotally connected as at 118 for tilting movements about a horizontal axis running along the length of the vehicle. A hydraulic cylinder and piston means 120 is interconnected between a portion of one of the axles of the vehicle and the vehicle chassis so that the chassis can be moved relative to the wheels of the vehicle about the pivotal axis. Suitable connections or controls are provided for controlling a flow of hydraulic fluid to and from the cylinder and piston means 120, and the vehicle can then be tilted to maintain the tower in a perfectly upright vertical position on various types of sloping terrain. This feature permits the vehicle to be maintained in a safer, more comfortable and more reliable actuating position for all work situations. Also, the tower can be angled for special work functions.

Looking to FIGURE 13, a novel construction is illustrated for the steering and seating arrangement for the vehicle of this invention. A seat 132 is mounted on a pedestal 134- for rotation about a ISO-degree arc. The seat 132 is also supported on a linking frame structure 136 which carries a steering wheel 138 and all necessary control devices for connecting the steering wheel to steering linkages of the vehicle. The steering wheel, its support structure, and the seat are rotatable about a vertical axis of the pedestal so that the operator can move the seat and all steering controls to any desired direction for operation of the vehicle. A foot lever means 140 is interconnected to conventional releasing and locking devices for rotating or locking the seat, as desired. When the operator wishes to rotate the seat and the steering controls in a new direction, he merely presses the foot lever 140 downwardly for releasing the seat from a locked position on the pedestal 134 and then the entire seat and steering assembly can be moved as an integral unit to a new position. This feature is especially useful for moving the seat and steering controls from a first direction for highway travel to a second direction for operation of the hammer means. It will be apparent that the novel seating and steering mechanism of this invention can also be constructed to move in arcs which are greater than degrees.

Having described the essential features of the invention with reference to a preferred embodiment, it can be seen that an improved device has been provided which greatly increases the work capacity of a hammering type of vehicle. The working tool means 24 is connected to the weighted means 20 so that the tool can be easily removed and replaced by other types of tools. For example, the vehicle may be used in a pavement breaking operation and then the tool 24 may be replaced with a tool for tamping fill earth which is replaced or used at the build ing site. In addition, the vehicle is provided with an earthworking blade 130 which permits the vehicle to be used in a variety of job requirements associated with its hammering functions.

Although reference has been made to a single embodiment, it will be appreciated that variations in this invention will become obvious to those skilled in the art, and such variations are intended to be included Within the scope of this invention.

What is claimed is:

1. In a utility vehicle having a traversing movable vertical tower means for lifting and guiding a hammer means which can be dropped for performing work such as compacting earth or breaking up pavement or other objects, the improvement comprising:

hydraulic actuating and control means for lifting said hammer means to an upper position in said tower for dropping therefrom, said hydraulic actuating means including a hydraulic cylinder and piston mounted in a housing structure separately from said tower, said housing structure being mounted on said utility vehicle so that it can remain in a fixed position relative to traversing movements of said tower, and including means for traversing said tower from side to side of said vehicle, whereby said towel can be traversed from side to side of said vehicle without interfering with hydraulic hoses and other hydraulic devices associated with the hydraulic actuating and control means, said cylinder and piston being connected to a cable and sheave means mounted in said housing structure with one end of said cable connected to the hammer means for lifting said hammer means when said piston is actuated by fluid pressure in a first direction in said cylinder, and for dropping the hammer means when fluid pressure is released from said cylinder to permit movement of said piston in a second direction in said cylinder.

2. The improvement of claim 1 wherein a second end of said cable is attached to a portion of said tower, whereby transverse movements of said tower will adjust the length or" cable available to support said hammer means to compensate for the transverse movement of the tower and to maintain said hammer at a particular level relative to said tower.

3. The improvement of claim 1 and including:

tilting means for tilting the chassis of said vehicle relative to the wheels of said vehicle and about a longitudinal horizontal axis of said vehicle, whereby a tilting of said chassis will tilt the tower and its hammer means relative to the wheels of the vehicle.

4. The improvement of claim 1 and including means for lowering said tower into a horizontal plane for storage on said vehicle when said hammer is not being operated.

5. The improvement of claim 1 and including a steering and Seating assembly mounted on said vehicle, wherein said steering and seating assembly is movable as a unit about a vertical axis, whereby an operator can move the assembly to a first position for highway travel and to a second position for operating the hammer means in said tower.

6. In a utility vehicle for hammering pavement or other objects, the combination comprising:

a tower means mounted on said vehicle for lifting and dropping a hammer means in a vertical path, said tower means including traversing means for moving the tower from side to side of said vehicle.

hydraulic actuating and control means for lifting said hammer means to an upper position in said tower for dropping therefrom, said hydraulic actuating means including a hydraulic cylinder and piston mounted in a housing structure separately from said tower means, said housing structure being mounted on said utility vehicle so that it can remain in a fixed position relative to traversing movements of said tower, whereby said tower can be traversed from side to side of said vehicle without interfering with hydraulic hoses and other hydraulic devices associated with said hydraulic actuating and control means.

7. The combination of claim 6 and including means for moving said tower into a stored position when said hammer is not being operated.

8. The combination of claim 6 and including:

tilting means for tilting the chassis of said vehicle relative to the wheels of the vehicle and about a longitudinal horizontal axis of said vehicle, whereby a tilting of said chassis will tilt the tower and its hammer means relative to the wheels of the vehicle.

9. The combination of claim 6 and including means for controlling the rate of lifting and dropping said hammer means.

10. The improvement of claim 6 and including a steering and seating assembly mounted on said vehicle, wherein said steering and seating assembly is movable as a unit about a vertical axis, whereby an operator can move the assembly to a first position for highway travel and to a second position for operating the hammer means in said tower.

11. The combination of claim 6 and including:

a first driving means for propelling said vehicle for relatively rapid movement from one job location to another, said first driving means having a gear transmission for changing driving speeds of said vehicle relative to engine speeds,

a second driving means for propelling said vehicle at relatively slow rates of movement when said vehicle is being used in a hammering operation, said second driving means being operative separately from said gear transmission of said first driving means, and

means for disengaging said first driving means from driving connection with said vehicle and for engaging said second driving means when said vehicle is to be used in a hammering operation, whereby vibrations from said hammering operation will not be transmitted through said gear transmission even though said vehicle is being propelled while the hammer means is being operated.

References Cited UNITED STATES PATENTS 2,790,648 4/1957 Sweetland 2806 2,805,847 9/1957 Malloy 173-86 3,088,385 5/1963 Dorkins et a1. 17528 3,088,537 5/1963 Le Tourneau ISO-77 3,172,483 3/1965 Spitzer 173--28 3,184,867 5/1965 Symmank 2806.11 3,195,913 7/1965 Hallsworth --77 3,223,193 12/1965 Reynolds et al. 180-77 3,225,842 12/ 1965 Roeschen 17324 1,381,314 6/1921 Krupp 173124 ERNEST R. PURSER, Primary Examiner.