US3664527A

US3664527A - Material handling apparatus

Info

Publication number: US3664527A
Application number: US875272A
Authority: US
Inventors: Ralph H Short
Original assignee: Clark Equipment Co
Current assignee: Doosan Bobcat North America Inc
Priority date: 1969-11-10
Filing date: 1969-11-10
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23

Abstract

An excavating shovel and backhoe combination including a telescopic boom on the outer end of which a boom arm is pivotally mounted. The boom arm is rotatable about its longitudinal axis to rotate a bucket pivotally mounted on the lower end thereof. A bucket pivot hydraulic cylinder is mounted completely on the rotatable portion of the boom arm to be rotatable with the bucket.

Description

United States Patent Short [45] May 23, 1972 [54] MATERIAL HANDLING APPARATUS 2,927,706 3/1960 Mork ..214/13s I 3,184,085 5/1965 Randall et al.. ....214/141 X {72] Invent Ralph Ohm 3,445,016 5/1969 Tomlinson ..214/138 73 Assi e: Clark ui m t C an B h 1 gm Mich p FOREIGN PATENTS OR APPLICATIONS [221 Filed: Nov. 10, 1969 717,253 9/1965 Great Britain ..214/141 1211 Appl. No: 875,272 Primary Examiner-Gerald M. Forlenza Assistant Examiner-Jerold M. Forsberg Att0rneyl5ewis J. Lamm [52] U.S.Cl. ..2l4/138 R,2l4/14l I [5 l Int. Cl. l ..E02f 3/00 57 ABSTRACT [58] Field ofSearch.. ....214/14l, 138, 1 CM, 147 G,

2 4 47 s An excavating shovel and backhoe combination including a telescopic boom on the outer end of which a boom arm is [56] Reerences Cited pivotally mounted. The boom arm is rotatable about its longitudinal axis to rotate a, bucket pivotally mounted on the UNITED STATES PATENTS lower end thereof. A bucket pivot hydraulic cylinder is mounted completely on the rotatable portion of the boom arm 3,45 1,224 6/1969 COIBChIa et a1. ..2l4/l RCM to be rotatable i the bucket. $204,795 9/1965 Larson ...2l4/147 AS 3,549,032 12/1970 Krause, Jr. ..214/147 G 4 Claims, 7 Drawing Figures PATENTED MAY 2 3 m2 SHEET 2 OF 4 MATERIAL HANDLING APPARATUS BACKGROUND OF THE INVENTION This invention relates to material handling apparatus and, more particularly, to such apparatus having vertically swinging load supports.

I-Ieretofore boom supported bucket-type excavators had been available wherein means are provided to rotate the bucket from a rearwardly directed backhoe position to a forwardly directed shovel position. However, such convertible excavators have not always been fully acceptable because they were unnecessarily complicated or structurally unsound. In addition, such convertible arrangements were not always acceptable because they had a relatively limited operational working range or characteristic.

SUMMARY OF THE INVENTION It is the general object of the present invention to provide a material handling apparatus that circumvents or minimizes the problems heretofore noted.

In achieving this general object, the present invention provides an elongated boom assembly having first and second sections, the first section being pivotally connected to a vehicle for pivotal movement in a vertical direction. The second section is moveable along the longitudinal axis of the boom relative to the first section. An elongated boom arm assembly is pivotally connected adjacent one end of the second boom section for pivotal movement in a vertical direction, and a material handling tool is mounted on the free end of the boom arm assembly. Of particular significance in combination with the longitudinal relatively moveable first and second sections of the boom is the provision of a boom arm assembly comprising first and second sections, the second boom arm section being rotatable about the longitudinal axis of the boom arm assembly relative to the first boom arm section.

In a preferred embodiment of the present invention motor means for pivoting the tool about an axis transverse to the longitudinal axis of the boom arm assembly is provided, the motor means being mounted completely on said second boom arm section.

BRIEF DESCRIPTION OF THE DRAWINGS In describing the present invention reference will be made to the accompanying drawings forming a part of the instant disclosure wherein;

FIG. 1 is a perspective view of a mobile boom-type excavator embodying the present invention wherein an excavating bucket is positioned on the boom arm in a forwardly directed shovel position;

FIG. 2 is a fragmentary perspective view of the boom and boom arm shown in FIG. 1 but wherein the excavating bucket is depicted in a rearwardly directed backhoe position;

FIG. 3 is a schematic view of one available operational cycle of the excavator shown in FIG. 1 wherein the bucket is positioned to function as a backhoe;

FIG. 4 is a fragmentary, schematic bottom view of the bucket and boom arm of the excavator shown in FIG. 1 illustrating a range of operative rotational positions of the bucket according to the present invention;

FIG. 5 is a fragmentary side view, partially in cross-section, of the bucket and boom arm of the excavator shown in FIG. 1;

FIG. 6 is a fragmentary front view partially in cross-section and taken along line 6-6 in FIG. 5; and

FIG. 7 is a schematic diagram of a hydraulic system adapted to be used in connection with the excavator shown in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION Referring in more detail to FIG. 1 of the drawings, the present invention is adapted for use with a material handling apparatus or self-propelled excavator 10. The excavator 10 generally comprises a chassis 12 pivotally mounted on a tracktype undercarriage 14 of the like by a turntable assembly 16 for swinging movement about a vertical axis. Pivotally mounted on the chassis 12 for pivotal movement in a vertical direction about a horizontal axis 18 (FIG. 3) is a boom assembly 20.

The boom assembly 20 comprises a first section 22, box-like in cross-section, and pivotal about the horizontal axis 18 by a pair of double acting hydraulic boom hoist cylinders or

motors

24 and 26 pivotally connected between the chassis 12 and the outer end of the first section 22. Telescopically received in the first section 22'is a second or outer section 28 which is also box-like in cross-section. The second section 28 is moveable along the longitudinal axis of the first section 22 by a double acting hydraulic boom extension or crowd cylinder or motor 30 (FIG. 7) positioned within the box-like first and

second boom sections

22 and 28 and pivotally connected therebetween. The second section 28 includes a downwardly depending portion 32 on the outer end of which a boom arm assembly 34 is pivotally mounted for pivoting movement in a vertical direction about a horizontal axis pivot pin 36. Such movement is effected by a double acting hydraulic boom arm cylinder or motor 38 (FIG. 3). The cylinder 38 is pivotally connected between the second section 28 of the boom assembly 20 and the boom arm assembly 34. Although the boom assembly 20 is described as comprising two telescopic sections, it should be appreciated that a greater number of telescopic sections may be provided.

The boom arm assembly 34 comprises a first or upper section 40 rotatably connected to a second or lower section 42 by a coupling or ring assembly 44 for relative rotational movement about the longitudinal axis of the boom arm assembly 34. To effect rotation of the lower section 42, which is boxlike in cross-section, a double acting hydraulic boom arm rotation cylinder assembly or motor 46 is provided within the lower section 42 as shown in FIGS. 5 and 6.

The ring assembly 44 comprises an anti-friction bearing assembly having relatively rotatably inner and outer races 48 and 50 fixed to the upper and lower

boom arm sections

40 and 42, respectively, to receive conventional bearing rollers 52 therebetween. F ixedly depending from the upper section 40 is a stub shaft 54 having a first bevel gear 58 fixed to the lower end thereof. The first bevel gear 58 engages a second bevel gear 60 splined to a cross shaft 62, the outboard ends of which are rotatably mounted in a pair of bearings 64 in the walls of the box-like lower section 42. A pinion gear 66 is splined on the cross shaft 62 for driving engagement with a rack 68. The rack 68 is fixed on the upper end of a piston rod 70 of the hydraulic cylinder assembly 46, the lower end of which is pivotally mounted on a pin 74 supported in the lower end of the lower boom arm section 42. A rack guide 75 (FIG. 6) is mounted within the upper end of the lower boom arm section 42 to guide movement of the rack 68 upon extension or retraction of the cylinder assembly 46. Such movement causes rotation of the pinion 66 and bevel gear 60 ultimately effecting rotation of the lower boom arm section 42 relative to upper boom arm section 40 about the longitudinal axis of the boom arm.

An excavator bucket assembly 76 is pivotally mounted on the lower end of the lower boom arm section 42 for pivotal movement about a horizontal axis pivot pin 78. To pivot the bucket assembly 76, a double acting hydraulic bucket pivot cylinder assembly or motor 80 is provided. The upper end of the hydraulic cylinder assembly 80 is pivotally connected by a pin 82 to brackets 84 fixed to a longitudinal side of the lower boom section 42. The lower end of a piston rod 86 of the cylinder assembly 80 is pivotally connected to a cross shaft 88 (FIGS. 4 and 5) which pivotally supports a pair of first bucket links 90, the lower ends of which are pivotally connected to a pair of bucket wings 91 by pivot pins 92. Pivotally mounted on the outboard ends of the cross shaft 88 are a pair of second bucket links 94, the lower ends of which are mounted on the outboard ends of the cross shaft 74 supporting the bucket cylinder assembly 46.

To control the excavator shown in FIG. 1 of the drawings, the present invention provides a generally conventional hydraulic system schematically illustrated in FIG. 7. An internal combustion engine 100 for driving the excavator is drivingly connected to a source of fluid under pressure, such as a pump assembly 102. The pump assembly 102 may comprise three radially mounted hydraulic pumps, 104, 106 and 108. The pump 104 is supplied from a reservoir 110 and the output thereof may be directed through a line 112 and a relief valve 114 to a manually controlled boom hoist valve 116 for controlling the

boom hoist cylinders

24 and 26. Alternately, fluid from the pump 104 may be directed through the boom hoist valve 116 to a manually controlled bucket valve 118 through telescopic tubes 120 positioned within the boom assembly to a lock valve 122 for controlling the bucket cylinder 80.

Fluid from the pump 106 may be directed through a line 124 and a relief valve 126 to a manually controlled selector valve 128 adapted to direct fluid flow to either hydraulic motors (not shown) for driving the undercarriage assembly 14 or through a line 130 to a manually controlled boom crowd valve 132 for controlling the boom crowd cylinder 30. Alternately, fluid from the pump 106 may be directed through the boom crowd valve 132 to a manually controlled boom arm valve 134 through telescopic tubes 135 positioned within the boom assembly 20 and appropriate lines to a locked valve 136 for controlling the boom arm cylinder 38.

Fluid from the pump 108 may be directed through a priority valve 138 and a line 140 to a manually controlled rotation valve 142 through longitudinally extensible coiled hose type lines 144 positioned in the boom assembly 20 and to a lock valve 146 for controlling the arm rotation cylinder 46. Alternately, fluid may be directed from the priority valve 138 to a selector valve 148 to the hydraulic motor means (not shown) for swinging the chassis 12 around a vertical axis relative to the track assembly 14.

Manual controls

150, 152, 154, 156 and 158 are provided to control actuation of the

various valve assemblies

116 and 118, 132, 134 and 142.

Of particular significance is the aspect of the present invention wherein the arm rotation valve assembly 142 may be actuated to extend or retract the arm rotation cylinder 46 thereby causing rotation of the lower boom arm section 42 relative to the upper boom arm section 40. In this manner, any operating position between the extremes shown schematically in FIG. 4, may be selected without resort to more complex arrangements including expensive rotary hydraulic motors or the like. Additionally, an extremely wide and flexible working range, complemented by longitudinal extension or retraction of the boom assembly 20 or pivotal adjustment of the boom arm assembly 34, may be achieved as schematically illustrated in FIG. 3. Combined adjustment of the controls for these features offers an operational range the extent of which had not heretofore been enjoyed.

Of additional significance is the aspect of the present invention wherein the bucket pivot cylinder assembly 46 is mounted completely on, and rotates with the lower boom arm section 42. This is because in a combination or convertible shovelbackhoe excavator the bucket cylinder assembly 46 must be capable of moving the bucket assembly 76 to both extreme forward and rearward positions, as shown in FIGS. 2 and 3 of drawings, if this bucket is to function as either a shovel or a backhoe. Prior arrangements wherein a bucket pivot cylinder or motor were mounted in whole or in part on the rotationally fixed portion of a boom arm, have not always proved satisfactory. In such arrangements the stroke of the cylinder or the like had to be excessively long, or the mechanism complicated, to provide the desired full range of movement required in a convertible shovel-backhoe excavator. Such problems are circumvented by the present invention.

Although but one embodiment of the present invention has been described, it should be appreciated that various substitutions for the basic or conventional structure, and modifications of the novel aspects of the described embodiment may be made which fall within the concept and scope of the present invention which is to be defined by the appended claims.

I claim:

1. In a material handling apparatus including an elongated boom assembly having a longitudinal axis, the boom assembly adapted to be pivotally connected to a vehicle for pivotal movement in a vertical direction, an elongated boom arm as sembly having a longitudinal axis, the boom arm assembly being pivotally connected to the boom assembly for pivotal movement in a vertical direction, one of said assemblies being extensible along its longitudinal axis, a material handling tool mounted on the boom arm assembly for pivotal movement about an axis transverse to the longitudinal axis of the boom arm assembly;

the improvement wherein said boom arm assembly comprises first and second rotatably connected sections, said second boom arm section pivotally supporting the tool, and first motor means for rotating said second boom arm section about the longitudinal axis of said boom arm assembly,

in which said boom assembly includes first and second sections, said second boom section being moveable along the longitudinal axis of said boom assembly relative to said first boom section, second motor means for longitudinally moving said second boom section, said first boom section being adapted to be pivotally connected to the vehicle, said first boom arm section being pivotally connected adjacent one end thereof to said second boom section,

said first boom section being adapted to be pivotally connected to the vehicle for pivotal movement about a vertical axis, and said tool comprising an excavating bucket, and

wherein said first motor means comprises an extensible double acting hydraulic cylinder one end of which is pivotally connected to said second boom arm section, a toothed rack mounted on the other end of said cylinder, a pinion drive assembly drivingly engaging said rack and operatively connected to said first boom arm section for rotating said second boom arm section about the longitudinal axis of the boom arm assembly, and

wherein said second boom arm section is box-like in crosssection, said pinion drive assembly being positioned within said second boom arm section and including a stub shaft fixedly connected to said first boom arm section, a bevel gear fixedly mounted on said stub shaft, and a pinion gear drivingly engaging said bevel gear and operatively connected to said rack for rotating said second boom arm section relative to said first boom arm section upon extension or retraction of said cylinder.

2. In a material handling apparatus according to claim 1, wherein said improvement further comprises anti-friction bearing means operatively positioned between said first and second boom arm sections for facilitating rotational movement of said second boom arm section about the longitudinal axis of the boom arm assembly.

3. In a material handling apparatus according to claim 2, wherein said improvement further comprises third motor means for pivoting said bucket about said transverse axis, said third motor means comprising an extensible double acting hydraulic bucket cylinder one end of which is pivotally connected to an upper end of said second boom arm section, first link means pivotally connecting the other end of said bucket cylinder to said bucket, and second link means pivotally connecting said other end of the bucket cylinder to a lower end of said second boom arm section.

4. In a material handling apparatus according to claim 3 wherein said first and second boom sections are box-like in cross-section and said second motor means includes an extensible double acting hydraulic boom cylinder positioned within and connected between said first and second boom sections, and extensible fluid line means for said first, second and third motor means positioned within said first and second boom sections.

Claims

1. In a material handling apparatus including an elongated boom assembly having a longitudinal axis, the boom assembly adapted to be pivotally connected to a vehicle for pivotal movement in a vertical direction, an elongated boom arm assembly having a longitudinal axis, the boom arm assembly being pivotally connected to the boom assembly for pivotal movement in a vertical direction, one of said assemblies being extensible along its longitudinal axis, a material handling tool mounted on the boom arm assembly for pivotal movement about an axis transverse to the longitudinal axis of the boom arm assembly; the improvement wherein said boom arm assembly comprises first and second rotatably connected sections, said second boom arm section pivotally supporting the tool, and first motor means for rotating said second boom arm section about the longitudinal axis of said boom arm assembly, in which said boom assembly includes first and second sections, said second boom section being moveable along the longitudinal axis of said boom assembly relative to said first boom section, second motor means for longitudinally moving said second boom section, said first boom section being adapted to be pivotally connected to the vehicle, said first boom arm section being pivotally connected adjacent one end thereof to said second boom section, said first boom section being adapted to be pivotally connected to the vehicle for pivotal movement about a vertical axis, and said tool comprising an excavating bucket, and wherein said first motor means comprises an extensible double acting hydraulic cylinder one end of which is pivotally connected to said second boom arm section, a toothed rack mounted on the other end of said cylinder, a pinion drive assembly drivingly engaging said rack and operatively connected to said first boom arm section for rotating said second boom arm section about the longitudinal axis of the boom arm assembly, and wherein said second boom arm section is box-like in crosssection, said pinion drive assembly being positioned within said second boom arm section and including a stub shaft fixedly connected to said first boom arm section, a bevel gear fixedly mounted on said stub shaft, and a pinion gear drivingly engaging said bevel gear and operatively connected to said rack for rotating said second boom arm section relative to said first boom arm section upon extension or retraction of said cylinder.