US3543945A - Truck mounted crane - Google Patents

Description

United States Patent [72] Inventor Martin R. Nelson 4618 Russell Ave. North, Minneapolis, Minnesota 55412 [21] AppLNo. 723,340 [22] Filed March 20,1968 [45] Patented Dec. 1,1970

[54] TRUCK MOUNTED CRANE 1 Claim, 5 Drawing Figs.

[52] U.S.Cl 212/67, 212/55,212/145 {51] Int.Cl. 1366c 23/84 [50] Field ofSearch 212/66, 67, 69,55,59, 144

[ 56} References Cited UNITED STATES PATENTS 2,961,102 11/1960 Pitman 212/67 3,056,510 10/1962 Garnett..... 212/55 3,197,038 7/1965 Billings 212/69 Stock 212/67 2,365,168 12/1944 Billings..... 212/69 2,754,977 7/1956 Przybylski 212/67 3,289,855 12/1966 Gernhardt 212/67 Primary Examiner-Harvey C. Hornsby Att0rneyWilliamson, Palmatier & Bains ABSTRACT: A utility truck is provided with an upright frame structure secured to the vehicle chassis immediately behind the truck cab, the frame structure serving to support a mast assembly on which a multiple-section boom is pivotally supported. An upright bracket mounted on one side of the rear- Patented Dec. 1, 1970 3,543,945

Shoot or 2 I N VENI 0R. MART/N R. A/czsazv TRUCK MOUNTED CRANE There are on the market today a variety of mobile crane units, most of which comprise large, multiple-section hydraulic boom assemblies mounted on the flat beds of relatively large trucks. For the most part, these mobile craneunits are designed for heavy duty lifting operations, and the crane assemblies are so large and massive that there is very little space left on the truck beds for normal, load-carrying operations when the crane is not required.

My mobile crane unit is particularly characterized by the mounting of a hydraulically actuated crane assembly over the bed of a relatively small, utility truck in such a way that the boom assembly and support structure therefor will not significantly obstruct the cargo-carrying space or interfere with the loading and unloadingof articles therefrom when the crane is not being used.

This basic objective is accomplished by mounting an upright bracket on one side of the rear end of the truck, whereby the boom assembly will extend at an angle across the truck bed at an elevated position thereover when it is at rest in the bracket.

As a particularly advantageous feature of my mobile truck unit, I secure the frame structure for the mast assembly of the crane to the chassis of the truck in the space between the back i of the cab and the forward end of the truck bed. This arrangement insures a solid mounting for the crane assembly, and lends strength and rigidity to the entire crane unit as well as insuring equal distribution of the load forces over the entire truck chassis when a load is being lifted and swung by the crane boom.

As a further advantageous feature of my invention, I employ a double sheave and cable arrangement to rotate the crane boom, the cables extending in opposite directions from the sheave wheel and being actuated by hydraulic cylinders.

These and other object and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings, wherein like reference numerals have been used to designate like elements in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing my improved crane assembly mounted on a utility truck with the boom in its rest position;

FIG. 2 is a fragmentary, perspective view showing the hydraulic actuating arrangement for the pivoting of the crane boom and the raising and lowering of outrigger arms;

FIG. 3 is a side elevation view of the crane and outrigger arm assemblies;

FIG. 4 is a vertical, section view taken along lines 4-4 of FIG. 3, and showing the cable and sheave arrangement'for turning the crane boom; and

FIG. 5 is a rear, elevation view of the support structure .for holding the outer end of the crane boom when it is not being used.

A preferred embodiment of the invention is shown in FIGS. 1 and 3, wherein a utility truck 1 having a cab la and a cargo bed 1b is shown with my improved crane apparatus mounted thereon. A crane unit generally designated by reference numeral 2 has a multiple-section boom'assembly 4 comprised of an inner, base section 5 which telescopically receives outer boom section 6. Boom 4 is pivotally supported on an upright mast assembly generally indicated by numeral 8. Fixed standard of mast assembly 8 is rigidly secured to a frame assembly described below, and is reinforced by horizontally extending ribs 12 which serve to support spindle housing 14 extending therethrough. Spindle 16 is rotatably supported within housing 14 by means of upper and lower tapered, roller bearings 24 and 26, spindle 16 being connected at its upper end to a sheave wheel unit 18 by means of collar 20. Collar 20, being connected to spindle l6 and welded to the top of sheave unit 18, acts as a coupling so as to permit sheave wheel 18 to rotate with spindle l6. Retainer nut 22 on the top of spindle 16 further assists in holding the spindle in place.

Mast assembly 8 further includes a'rigid column 28 which performs the dual functions of pivotally supporting boom 4 for vertical movement about a horizontal axis 36, and connects boom 4 to sheave unit 18 so that it can rotate therewith on vertical spindle 16. The connection of column 28 to the rotatable spindle and sheave unit is accomplished by horizontally depending arms 3i) and 32 which are connected at their inner ends to spindle l6, and by upper bracket ears 34 which are welded to the top of sheave wheel 18. Thus, as sheave wheel unit 18 and spindle 16 are rotated by a cable drive arrangement more fully explained below, column 28 and boom 4 attached thereto are swung laterally so as to permit the crane unit to pick up and deliver loads on either side of truck The pivotal connection between the inner end of boom base section 5 andpin v36 extending horizontally through bracket ears 34-permits boom'assembly 4 to be raised and lowered by a conventional hydraulic actuating mechanism comprised of hydraulic cylinder 40 and reciprocating piston 44. Hydraulic cylinder 40 is pivotally supported at its lower end on bracket 38 by means of downwardly depending ear 42. The attachment of piston 44 to boom section 5 is accomplished by securing outer piston ear 46 to pivot pin 48 extending through bifurcated bracket 50, which is welded to the underside of boom section 5. Piston 44 is a conventional double-acting piston, which may be extended and retracted by hydraulic pressure to raise boom assembly 4 from its rest position of FIG. 1 to an elevated position as shown in FIG. 3.

A cableand wench arrangement, most clearly shown in FIG. 3, may also be utilized for raising and lowering loads. Cable 56 is attached at its end to wench 52, which is driven by gear motor 54. Cable 56 extends around pulley 58 mounted on column 28, and is'guided through a second pulley 60 attached to the outer end of boom section 6. Motor 54 is preferably a D.C. motor driven from the direct current power supply of truck cab 1a, and advantageously provided with a remote control device for the convenience of the operator.

Crane units of the type shown and described above normally employ some means for swinging the boom assembly from side to side. Such a boom turning device must not only be capable of imparting the necessary lateral movement to the crane boom, but it also must be so designed as to prevent the undesired free-swinging of the boom assembly. This is particularly true with respect to truck mounted crane units where the parking of the truck on the side of an incline when a load is being lifted and moved by the crane may cause the boom to swing freely in a dangerous and undesired manner. My unique arrangement for rotating boom-turning sheave l8 and preventing the undesired swinging of boom assembly 4 will now be described with particular reference to FIG. 4. The apparatus for turning spindle unit 18 is mounted on the same upright frame assembly which supports boom assembly 4 and its mast 8. The frame assembly is comprised of upright members 64 and 66 and upper and lower cross braces 68 and 74, all of these pieces being preferably steel beams. Frame bar 70 rests on top of cross brace 68 and assists in supporting rigid standard 10 of mast assembly 8, standard 10 being secured to bar 70 and upright frame member 66 as by welding. FIGS. 1 and 3 best illustrate the manner in which standard 10 of the mast assembly 8 is assembled to frame bar 70 and upright member 66. The frame assembly is secured to the truck by welding or bolting upright member 64 to longitudinally extendingbeams 72 and 73 of the truck chassis. Extending upwardly from cross beam 68 are sheave support brackets 76 and 78 which rotatably support sheave or pulley wheels 80 and 82. Sheave unit 18 is comprised of two separate cable grooves 19 and 21. This double sheave arrangement may be provided by utilizing two separate sheaves or pulleys and securing them together or utilizing a single sheave wheel with two grooves formed therein as shown in the preferred embodiment of sheave wheel 18. Oppositely directed turning cables 84 and 86 are secured at their inner ends within sheave grooves 19 and 21 respectively, and extend outwardly around pulley wheels 80 and 82 to a point of connection with hydraulic ally actuated pistons 90 and 91. Bifurcated connecters, only one of which is shown at 88 are employed to connect cables 84 and 86 to pistons 90 and 91. Pistons 90 and 91 are mounted for reciprocal movement within hydraulic cylinders 92 and 93, which are of the single-acting type and have one hydraulic fluid connection 94 at the upper end thereof. FIG. 2 clearly illustrates one of the hydraulic cylinders 92, its fluid connection 94 and the manner in which turning cable 84 is connected to piston 90. Sheave unit 18 is rotated so as to swing boom assembly 4 from one side of truck 1 to the other by applying hydraulic pressure to the top of either piston 90 or 91. For example, the application of pressurized hydraulic fluid to the top of piston 91 will cause that piston to move downwardly to the position shown in FIG. 4, I thereby pulling cable 86 downwardly and causing sheave 18 to rotate in a clockwise direction whereby boom assembly 4 will be swung towards the left side of truck 1 when viewed from the rear as shown in FIG.

To insure that boom assembly 4 does not swing freely and prematurely when it is desired to move it from one side of truck 1 to the other, I provide a second, braking cable 96 which is connected at its oppositeends to pistons 90 and 91. Cable 96 is directed outwardly over pulley wheels 98, 100, 101, and 99 which are rotatably supported from lower cross beam 74. The tension on cable 96 may be adjusted so as to maintain a tight connection between pistons 90 and 91 by changing the position of pulley 101 within slot 104 of adjustable mounting bracket 102. The connection of pistons 90 and 91 through cable 96 insures that these two pistons will move simultaneously, in opposite directions, thereby preventing the formation of slack in cables 84 or 86 which would permit the free swinging movement of boom assembly 4. Also, if truck 1 were parked on an incline with boom assembly 4 being held in an uphill or elevated position with hydraulic pressure holding piston 91 in the downward position of FIG. 4, boom assembly 4 would tend to swing downwardly in a counterclockwise direction by gravity the instant that pressurized hydraulic fluid is released from the top of piston 1 and directed by appropriate valves to the top of piston 90. The restraining force exerted on piston piston 91 by cable 96 and piston 90 to which it is connected prevents the undesired, rapid extension of piston 91 necessary for cable 86 to move upwardly to permit sheave 18 to rotate in a counterclockwise direction.

As is indicated in FIGS. 1 through 3, the aforesaid frame assembly comprised of upright members 64 and 66 and cross braces 68 and 74 is conveniently positioned between the rear of truck cab in and cargo bed 11) and secured to chassis members 72 and 73. This location of the crane support frame has several advantages. In addition to minimizing the obstruction of the cargo bed 112 by the crane support structure, it also serves to evenly distribute the weight of the crane and the load being hoisted over the truck chassis, thereby assisting in preventing the tipping of the truck when a load is being lifted by the crane and boom assembly 4 is being swung from one side to the other. To further stabilize the truck 1 when loads are being lifted and shifted by boom assembly 4, I provide outrigger arms 106 having foot pads 108 and-109 mounted on pins 110 at the outer ends thereof. Referring now to FIGS. 2 and 3, outrigger arms 106 are pivotally supported on horizontal pivot pins 114 extending through bifurcated bracket arms 112 extending outwardly from the lower ends of upright frame member 64. The raising and lowering of outrigger arms 106 is accomplished by actuating legs 116 and 118 connected together at a knee joint by bifurcated connector 120, pin 121 and ear 122 through which pin 121 extends. A portion 117 of lower leg 116 extends upwardly beyond the lower end of leg 118 in contact therewith in the extended position of outrigger arm 106 shown in FIG. 2. Connecter plate 124 at the outer end of leg 116 is secured within slot 126 formed in outrigger arm 106 by means of pin 128 extending therethrough. The upper end of leg 118 is connected, as by welding, to a lever arm 130 which pivots about pin 132 extending through ears 134 of bracket 136. Bracket 136, like bracket 112, is supported by upright frame, member 64. Bifurcated connecter 138 serves to attach one end of lever arm to the outer end of piston 140 of hydraulic cylinder 142. Hydraulic cylinder 142 is of the double-acting type and is provided with upper and lower hydraulic fluid connections 143 and 144.

in order to lower outrigger arms 106 to the ground-engaging position shown in FIGS. 2 and 3, hydraulic piston 140 is reciprocated downwardly, whereby the outer end of lever arm 130 is swung rearwardly and upwardly. This movement of lever arm 130 causes arms 116 and 118 to snap outwardly from their collapsed position to the straight position shown in FIG. 2. Leg 116 will swing downwardly until pad 108 engages the ground, and then the continued retraction of piston rod 140 will cause extension 117 of leg 116 to engage the lower end of leg 118 and lock the knee joint between legs 116 and 118. To raise outrigger arms 106 to the stored position shown in FIG. 1, hydraulic fluid is introduced through connection 144 at the lower end of cylinder 142 to move piston rod 140 upwardly. As the outer end of lever arm 130 swings downwardly from the position shown in FIG. 2, the force exerted by the outer end of upper leg 118 on extension 117 of leg 116 will cause the knee joint therebetween to collapse inwardly, and as the lower end of leg 118 swings in towards cylinder 142 it will pull leg 116 and outrigger arm 106 attached thereto inwardly and upwardly by reason of the connection between legs 116 and 118 at pin 121. Outrigger arms 106 will then be in the stored position of FIG. 1 in which they may be retained by placing a pin or lock through apertured ear 107'which extends through slot 105 in arms 106 when the arms are completely raised.

The mounting of outrigger arms 106 on opposite side legs 64 of the crane support frame permits the advantageous storing of outrigger arms 106 in the space at the rear of truck cab 1a when they are not being used. Moreover, the outrigger arms 106, when so positioned substantially midway of the length of the truck chassis, provide a maximum stabilizing effect when they are in engagement with the ground and a load .is being lifted and swung by boom assembly 4.

In order to support boom assembly 4 in such a way that it does not interfere with the use of cargo bed 1b when the crane is not being used, I provide a support structure therefor mounted at one side of the rear end of cargo bed 1b. To this end, upright braces are secured to rear end 147 of cargo bed sidewall 148, and a boom support member in the form of cross brace 151 is fastened to the top thereof as shown in FIGS. 1 and 5. Right angle brackets 152 and 153 are bolted, or otherwise secured, to the top of support member 151, these brackets being disposed at an angle with respect to the longitudinal axis of cargo bed 117 as indicated in FIG. 5. Thus, when boom assembly 4 is resting upon support member 151 in its position of nonuse as shown in FIG. 1, it will be restrained by brackets 152 and 153 at an oblique angle with respect to the longitudinal axis of cargo bed 1b and at an elevated position above the cargo bed. This arrangement insures that the boom assembly 4 and its support structure will present a minimum obstruction to cargo bed 11:, whereby articles may be loaded and unloaded from the cargo space between truck side panels 146 and 148 when the crane unit is not being used. Upright braces 150 are of such a height that cross member 151 will be disposed at substantially the same elevation as the base of boom section 5, whereby boom assembly 4 will extend in substantially a horizontal plane when it is at rest on support member 151'.

Hydraulic fluid for actuating all of the aforesaid power cylinders 40, 92, 93, 141 and 142 may be a supplied by a hydraulic pump (not shown) driven by a power takeoff connected to the transmission of truck 1 in a manner well known in the art. Hydraulic fluid will also be directed by this means to power cylinder 3 housed within boom base section 5 as shown in H6. 3. Cylinder 3 serves to extend and retract outer boom section 6.

Although I have shown and described my invention with respect to particular embodiments thereof, I anticipate that those skilled in the art may devise various changes and modifications which will be within the spirit and scope of my invention.

Iclaim:

l. A support structure for hydraulic crane boom mounted on a relatively small truck having a cab and a load-carrying bed, comprising in combination:

a sheave wheel unit having two circumferentially extending cable grooves therein, said sheave wheel unit being rotatably mounted on the upper end of an upright frame structure for swinging movement about a vertically ex tending axis, said framestructure being secured to the chassis of said truck immediately behind said cab and extending laterally between and being supported on the laterally spaced, longitudinally extending beams of the truck chassis;

means connecting said sheave wheel unit to the base end of the boom of a hydraulically actuated crane;

first and second turning cables having their inner ends secured within said two circumferentially extending cable grooves and extending laterally outwardly therefrom in opposite directions over said frame structure with their outer ends being guided downwardly over first and second pulley wheels rotatably supported on horizontal axes on the opposite, outside lateral extremities of said frame structure at the top thereof;

first and second hydraulic cylinders having hydraulically actuable pistons extending upwardly therefrom and connected to the outer, downwardly extending ends of said turning cables, said hydraulic cylinders being supported in upright positions on opposite sides of said frame structure outside of upright support members defining the lateral extremities of said frame structure; and

first and second outrigger arms on opposite sides of said truck, said arms being pivotally supported on opposite sides of said frame structure and movable about horizontal axes from a fully extended, ground engaging position to an upright, retracted position in which said arms are housed within a space between the rear of said cab and the front end of said load-carrying bed, each of said outrigger arms being pivotally supported at its inner end on a bifurcated bracket extending laterally outwardly from one of said upright support members near the bottom of said frame structure, and each of said outrigger arms being supported at its outer end by actuating linkage means pivotally connected to a second, bifurcated bracket member located above 'said first bifurcated bracket member on one of said upright support members of said frame structure, and said first and second hydraulic cylinders and pistons extending vertically through said first and second, bifurcated brackets; a hydraulic actuating cylinder for each of said outrigger arms, each of said actuating cylinders being mounted in an upright position and connected between said first and second bifurcated brackets outside of and parallel to said first and second turning cable hydraulic cylinders; a cable connected at one end thereof to one ofl said turning cable pistons and extending around guide pulleys to a point of connection with said second piston, said guide pulleys being rotatably supported on horizontal axes at the bottom of said frame structure on opposite sides thereof adjacent said first and second hydraulic cylinders, and one of said guide pulleys for said cable being movably mounted on a bracket so as to permit the adjustment of the tension of said cable, whereby said cable serves to interconnect said pistons to prevent the undesired movement of said turning cables and the free swinging of said crane boom.

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