US3047170A

US3047170A - Earth handling apparatus

Info

Publication number: US3047170A
Application number: US35765A
Authority: US
Inventors: Frank G Hough; Robert M Peterson; Wallace H Gilson
Original assignee: HY DYNAMIC CO
Current assignee: HY DYNAMIC CO
Priority date: 1960-06-13
Filing date: 1960-06-13
Publication date: 1962-07-31
Anticipated expiration: 1979-07-31

Description

July 31, 1962 F. G. HOUGH ET AL 3,047,170

EARTH HANDLING APPARATUS Filed June 15, 1960 3 Sheets-Sheet l M an H INVENTORS FRANK G. HOUGH ROBERT M. PETERSON WAL'LACE H. emsoN July 31, 1962 F, G. HOUGH ET AL EARTH HANDLING APPARATUS Filed June 13, 1960 3 Sheets-Sheet 2 x m m m FRANK G. HOUGH ROBERT M. PETERSON WALLACE H. G\\L$0N' w y w July 31, 1962 F. G. HOUGH ETAL EARTH HANDLING APPARATUS 3 Sheets-Sheet 3 Filed June 13, 1960 INVENT0R5 FRANK G. HOUGH ROBERT M. PETERsoN' B D WALLACE H. =\LsoN FLH 5 fifi ill? Fatented July 31, 1962 3,047,170 EARTH HANDLING APPARATUS Frank G. Hough, Highland Park, and Robert M. Peterson and Wallace H. Gilson, Libertyville, 111., assignors to The lily-Dynamic Co, a corporation of Illinois Filed June 13, 196i Ser. No. 35,765 Claims. (ill. 214-131) This invention relates to earth handling apparatus and, more particularly, to earth handling apparatus of the selfpropelled type which is equipped with earth handling or working implements fore and aft.

Exemplary of the apparatus contemplated by the invention is a tractor equipped with a front end loader and a back hoe. Such apparatus finds wide use in a variety of excavating, trenching, backfilling, loading, etc. operations.

It is an object of this invention to provide an integrated piece of earth-working equipment-that is, a self-propelled vehicle having fore and aft earth-working or handling elements wherein the entire assembly is characterized by maximum strength with minimum weight.

Another object is to provide a self-propelled vehicle equipped at one end with a loader element and at the other end with a hoe element, the vehicle including a novel frame for supporting the propelling and earth-working elements. In particular, the frame includes an intermediate, longitudinally-extending portion adapted to preferentially flex. This departs from classical design practice, which would dictate substantial reinforcement at the area of maximum bending movement.

Still another object is to provide a novel earth handling apparatus characterized by having a unitary tractor-like construction equipped with implements in the nature of a loader and a hoe. Such equipment for this purpose in the past has generally taken the form of tractors equipped with attachments fore and aft, these being installed on conventional tractor chassis. As such, the prior structures were of limited usefulness: their light weight, for example, precluded advantageous use in many necessary trenching and filling operations. The provision of additional weight on such equipment worsened the problem, since it promoted the tendency of the tractor skeleton to fail under working stresses. Although heavier, stronger equipment was available, such equipment was uniformly provided with crawlers which lacked the advantageous operational flexibility of a tractor, especially in ready relocatability over highways and the like.

Yet another object is to provide a self-propelled earth handling machine which includes a generally rectangular frame equipped with front and rear axles, the front end of the frame being equipped with an implement in the nature of a front-end loader, pivotably integrated into and uniquely supported on the frame, the frame also being stabilized by a forwardly mounted motor.

A further object of the invention is to provide a novel earth handling apparatus equipped with fore and aft earth handling elements integrated into the apparatus frame, the rear end of the apparatus being uniquely rigidified to support the after element for several degrees of movement without unduly stressing the apparatus frame.

A still further object is to provide a tractor-type earth handler in which a front end loader and a back hoe may be employed cooperatively without overloading the tractor frame. As such, the inventive machine is self-extractable when mired and thus can function in areas heretofore inaccessible to tractors. Even more, this type of advantageous operation is available without having to resort to crawlers, which, though beneficial in some respects, are undesirable in a light weight, highly maneuverable vehicle. The inventive structure achieves the advantages of both the implement equipped tractor and the similarly equipped crawler without suffering from the disadvantages of these respective pieces of equipment. It is particularly suited for operation in soft ground, having a suitably high free board or ground clearance compared to the usual tractor and relatively low weight compared to the ordinary crawler.

Other objects and advantages of this invention may be seen in the details of construction and operation set down herein.

The invention will be explained in conjunction with the accompanying drawing in which FIG. 1 is a perspective view of equipment constructed in accordance with the teachings of this invention;

FIG. 2 is a side elevational view of a specific embodiment of the invention, namely the embodiment seen in FIG. 1, and which shows certain portions of the apparatus in broken line to designate alternative positions of movable parts of the apparatus;

FIG. 3 is a top plan view partially in section as would be seen along the line 33 of FIG. 6, of the main frame of the self-propelled vehicle;

FIG. 4 is a side elevational of the frame seen in FIG. 3;

FIG. 5 is an enlarged sectional view of a fragment of the frame as would be viewed along the sight line 55 of FIG. 4;

FIG. 6 is an end elevational view partially in section of the frame seen in FIGS. 3 and 4, more particularly the rear end of the main frame; and

FIG. 7 is the front end elevational view of the main frame seen in FIGS. 3 and 4.

In the illustration given and with particular reference to FIG. 2, the numeral 10 designates generally an embodiment of the earth working apparatus with which this invention is concerned. The apparatus 141 is generally of a tractor-type construction (this fact being readily appreciable from a consideration of FIG. 1) and is equipped with front wheels 11 and rear wheels 12. The forward end of the apparatus 10 is equipped with a front end loader 13 and a back hoe generally designated 14 is located at the rear end of the apparatus.

The back hoe 14 includes a bucket or scoop 15 which is pivotably connected to one end of a dipper stick 16. The dipper stick 16 at its upper end is pivotably connected to a boom 17.

In accordance with conventional practice, the bucket or scoop 15 is movable through a vertical arc and relative to the dipper stick 16. For this purpose, the dipper stick 16 and the bucket 15 are interconnected by means of a cylinder and piston rod unit 18. The dipper stick 16' is also pivotable through a vertical arc and relative, in this respect, to the boom 17, this being achieved through the operation of a second cylinder and piston rod unit 19. The dipper stick unit 19 extends from the extreme upper end of the boom 17 to a point adjacent to but spaced from the lower end of the dipper stick 16. The boom 17 is also swingable through a vertical arc and this is achieved through the operation of a third cylinder and piston rod unit in the back hoe 14, this boom moving unit being designated by the numeral 20.

The boom 17 is mounted for rotation through a horizontal are, this being achieved through a pair of cylinder and piston rod units 21 masked by the vehicle portion of the apparatus 10 in FIG. 1 except for the piston rod end of one of the units which is designated by the numeral 21a. A portion of this unit 21 is seen in dotted line in FIG. 3. These horizontal rotation-inducing cylinder and piston rod units are interconnected between the back hoe 14- and a main frame generally designated 22 of the apparatus 10.

The frame 22 at its extreme rear end is equipped with an integral boom mounting bracket 23 (see particularly FIG. 3). The frame 22, also adjacent the rear end thereof, is equipped with pivotably mounted stabilizers generally designated 24 (see FIGS. 1 and 2) which are mounted for movement through a vertical are by means of the stabilizer cylinder and piston rod units 25. In FIG. 1 the stabilizers 25 are seen in retracted position while in FIG. 2, the stabilizers 25 are depressed and in ground gripping position.

Referring particularly to FIG. 2, the numeral 26 designates the front end loader bucket which is seen in broken line in two different conditions, the lower of the broken line conditions being designated 264 while the upper of the broken line conditions being designated 26b. The bucket 26 is pivotably mounted at the forward end of the loader arms 27 which are seen in broken line for indicating the elevated condition of the front end loader in which instance the load arms are designated by the numeral 27a. It will be appreciated that a pair of the load arms 27 are provided, one on each side of the apparatus 10, with the bucket 26 extending therebetween.

Each load arm 27 is equipped with a pivotably mounted cylinder and piston rod unit 28, the unit 28 also being pivotably connected to the bucket 26 to change the bucket position or angle. The position designated 26a occurs when the piston rod of the unit 28 is completely retracted while the position designated 26!) in FIG. 2 occurs when the piston rod is fully extended as would be the case in dumping.

The elevation and lowering of the arms 27 is brought about through a second cylinder and piston rod unit for each arm 27, the second unit being designated by the numeral 29. The unit 29 is connected at one end in a pivotable fashion with the load arm 27 with which it is associated and at its other end is connected to the main frame 22. The main frame 22 is equipped with a subframe or superstructure 30 (see particularly FIG. 4, which provides a pivotable mounting for the rear end of the load arms 27).

Referring now to FIG. 2, the numeral 31 designates a motor which is supported on the frame 22 and which operates through a transmission 32 to deliver power to a differential 33. The differential 33 is mounted in the rear axle 34, the rear axle 34 in turn being supported within supports 35 (see FIG. 3) provided on the main frame 22. The frame 22 is also equipped with a front axle support portion 36 (see FIG. 7), which supports a steering mechanism 37 actuated by means of a conventional steering wheel 38. The rear of the apparatus 10 is equipped with a drivers seat 39, forward of which are located the loader controls 40 and rearward of which are positioned the back hoe and stabilizer controls 41.

With the back hoe 14 and the front end loader 13 elevated relative to the ground, the apparatus 10 may be conveniently moved from one place to another under its own power, this being developed by the motor 31. When the front end loader is being employed for loading, back filling, etc., the controls 40 are moved appropriately to hydraulically pressurize the cylinder and piston rod units 28 and 29 and thus alter the condition of the bucket 26 and the load arms 27, respectively.

The operation of the back hoe is usually accompanied by the depressed condition of the stabilizers 24, i.e., the condition seen in FIG. 2. The operation of the back hoe 14 may result in a wide variety of stress applied to the apparatus 10, particularly the main frame 22. For example, torsional stresses arise when the back hoe 14 is pivoted horizontally so as to dig on one side or the other of the apparatus 10 rather than directly rearwardly thereof. This stress phenomenon is not limited to the operation of the back hoe 14 but also may be present in the operation of the front end loader 13-as where one side of the bucket 26 encounters a curb or other obstruction so as to eccentrically load the same. However, irrespective of any torsional stress, there is always present in frame 22 a bending stress developed by the cantilever arrangement of the two

earth handling elements

13 and 14. The operation of the front end loader 13 is accompanied by a tendency of the rear of the apparatus It} to be lifted off the ground. In the past, attempts to remedy this have included weighting the rear end of the apparatus 10 by several thousand pounds of metal. This resulted in localizing the bending stress at points intermediate the length of the vehicle with the possibility of the vehicle actually breaking in two. Where an ordinary farm tractor Was equipped with a front end loader in the form of an attachment, the tractor skeleton, i.e., the transmission frame, was often inadequate to withstand this stress so heavy supplemental longitudinal members were employed, reinforced at the points of maximum strain. These supplemental frames were provided beneath the main tractor skeleton and detracted measurably from the ground clearance. When such an implement was further equipped with a back hoe, the need for the rear end weighting was removed, but the operation of the back hoe posed additional and extremely serious problems of localized stress. Any attempt to employ the fore and aft implements coopera' tively, as where the tractor was mired, resulted in an entirely different stress pattern, in some cases the reverse of that ordinarily encountered during earth handling. It will be appreciated that it would be desirable to employ the front and rear implements in a co-acting fashion since simultaneous depression of the two would result in literally lifting the tractor upwardly and out of any mired condition. Also, the bucket 26 of the front end loader 13 could act as a pontoon or fulcrum point when the back hoe 14 is employed as a pusher so as to elevate the rear end preferentially. This desirable operation was only limitedly attainable at best in the prior art structures. In the inventive structure, this is not the case and the advantageous operation is achieved in large measure through the employment of an integrated frame construction of novel arrangement which will now be described with particular reference to FIGS. 3-7.

Referring now to FIGS. 3 and 4 in particular, it will be seen that the main frame 22 includes a pair of longitudinally extending

channel members

42 and 43 corresponding, respectively, to the right and left sides of the apparatus 10 when viewed looking forwardly. The forward ends of the

longitudinal members

42 and 43 are connected together in a rigid fashion by means of a transverse member 44. As can be seen from FIG. 7, the

longitudinally extending members

42 and 43 are channel shaped while the member 44 (see FIG. 4) is secured to these members on their lower sides. The member 44 is equipped with depending flanges 36a and 36b (designated only in FIG. 4) which cooperate with the front axle support portion 36 in providing a mounting for the steering mechanism 37. The interior or upper side of the member 44 is suitably braced as at 45 by integral webs. A front end casting 46 is provided which is equipped with a notch 47 (see FIG. 7) for the con venient mounting of the motor radiator 48 (see FIG. 2).

Reference to FIG. 3 reveals a pair of support brackets 49 spaced rearwardly of the rear edge 44a of the transverse member 44. The brackets 49 provide mounting pieces for the rear corners of the motor 31 while the transverse member 44 is apertured as at 441) to provide the third motor mounting point. From this, it will be seen that the motor serves as a rigidifying member to provide a rigid front end section extending rearwardly from the transverse member 44 to a point adjacent posts 50 (see FIGS. 3, 4 and 7) which serve as the pivotal mounting for the loader arm cylinder and piston rod units 29. An angle bracket structure 51 provided for each

longitudinal member

42 and 43 is rigidly secured thereto and provides the mounting for the posts 50.

The load arms 27, as mentioned previously, are supported on the subframe or super structure 30. The super structure 30 includes a pair of upstanding side plates 52, each plate 52 just rearward of the brackets 49 being vertically reinforced by a channel member 53 (see FIG. 7). Adjacent the upper end of each channel member 53, the associated plate 52 is equipped with a bearing 54. The bearings 54 are aligned transversely of the machine and serve as pivotal supports for the load arms 27. The plates 52 are connected transversely by a pair of

angle members

55 and 56 which are positioned in alignment with the bearings 54-. Thus a box section is provided which integrates the load arm supports with the main frame. In this connection, it is to be noted that the rear pivotal mounting of the load arms 27 is spaced just rearwardly of the pivot posts 5t) of the associated cylinder and piston rod units. This permits the cylinder and piston rod units 29 to extend generally vertically, to approximately the upper dotted line position of FIG. 2 without interfering with the load arm pivotal mountings at 54. Still referring to FIG. 2, it will be seen that each load arm 27 is of generally angled construction and equipped with a plate 57 adjacent the angled portion. The plate 57 provides a convenient structure for the pivotable attachment of the piston rod 29a of the cylinder and piston rod unit 29 and also for the butt-end clevis 28a of the bucket cylinder and piston rod unit 28.

The extreme rear end of the main frame 22 will now be described and with particular reference to FIGS. 3-6. Reference to FIG. 6 reveals that the longitudinal member 43 is seen in dotted line, the member 42 in section, these members at their extreme rearward end being interconnected by a massive transverse member or plate 58. The plate 53 extends a substantial distance below the lower edge of the

longitudinal members

42 and 43 and is rigidified in this portion by means of angle plates 59 interconnected between the

longitudinal members

42 and 43 and the rear transverse member 58 (see MG. 4). The boom mounting bracket, particularly the lower two bearings 23a and 2311, are provided integral with this plate which is centrally vertically reinforced by a channel member 60. Here it will be appreciated that the boom 17 of the back hoe 14 is provided with a pivotal lower box section 17a (see FIGS. 1 and 2) which pivotably supports both the boom itself (the element designated 17) and the boom cylinder and piston rod unit 20. The section 17a is suitably apertured and equipped with a shaft (not shown) which is received within the

boom brackets

23, 23a and 23b.

it is with this section 17a that the cylinder and piston rod units 21 equipped with the rods 21a are connected, the rods 21a extending through apertures 61 in the plate 6% while the butt-ends of these cylinder and piston rod units are trunnioned in recesses 62 in parallel transverse members 63 extending between vertical plates 64 and 65 (see FIG. 3). The plate 64 is welded to the adjacent longitudinal member, i.e., 42 in FlG. 6, while the plate 65 extends between the upper and lower transverse channels 66 and 67 respectively, these channels extending between the

longitudinal members

42 and 43.

As can be seen most clearly in the upper left hand portion of FIG. 3, the extreme rear end of the frame 22 is rigidified by means of a diagonal member 63 which extends from the rear transverse wall 58 to the left hand longitudinal member 43 where the intersection therewith the transverse member 67 occurs. A second, corresponding diagonal bracing member 69 is provided interconnecting the plate 58 adjacent the pivotal mounting of the back hoe 14 with the right hand longitudinal member 42 and the transverse channel 67. A second pair of diagonal bracing members are provided, only one of which is seen in FIG. 3, this diagonal bracing member being designated by the numeral 70 and also extending from the plate 58 to the longitudinal member 42. The forward connection of this diagonal member 7% is spaced forwardly of the corresponding connection of the diagonal member 69 and this joint occurs where the transverse channel 66 is coupled to the longitudinal member 42. Thus, the lower

diagonal members

63 and 69 are shorter than the upper diagonal members 7t) and thereby afford an open area at the rear end for the positioning of the differential 33 in the rear axle 34. Each of the diagonals 63-70 is T-shaped in cross section, the leg of the T being upstanding in the member 70 and depending in the member 69. The transverse channel 66 lies right over the rear axle so the cooperation of this member and the above-mentioned diagonal members 6840 provide a rigid rear section extending from the rear axle brackets 35 to the rear wall or plate 58. Gussets such as 71 may be provided connecting the diagonal members 68 and 69' with the

longitudinal members

43 and 42, respectively, and the angle braces 59 while other gussets 71a may be provided to stabilize the upper diagonal member 7t relative to the two

longitudinal members

42 and 43. Angle bracing on the top side of the

longitudinal members

42 and 43, corresponding to the angle bracing 59, is provided in the form of elements 72 (see FIG. 4).

Each longitudinal member is provided with a laterally extending flange 73 spaced forwardly of the rear plate 58 and which cooperates therewith in providing a mount for

bearings

74 and 75. The

bearings

74 and 75 support respectively the stabilizer cylinder and piston rod units 25 and the stabilizers 24.

As mentioned previously, the rigid section extending rearwardly from the rear axle 34 is provided through the cooperation of the diagonal members 68-70, the

longitudinal members

42 and 43 along with the angle bracing 59 and 72, and the

transverse members

66, 60 and 67 at the forward end of the rigid section, and by the rear plate 58 at the rear end thereof. Further, transverse rigidification is achieved through the bottom plate 76 which extends between the rear plate 58 and the flanges 73. All of this makes for a very stabilized operation of the back hoe 14, uniformly delivering the stresses developed thereby to the

longitudinal members

42 and 43 of the main frame 27.. It will be appreciated that the stress pattern changes during any movement of any portion of the back hoe 14. Once the boom 17 has been positioned in the desired orientation to the right or left of the apparatus lltl, scooping is generally effected by operation of the cylinder and piston rod unit 18.

This unit 18 is equipped with a piston rod 18a pivotably connected to a pair of

links

77 and 78. The link 77 in turn is pivotably connected to the dipper stick 16 as at 79 while the link 78 is pivotably connected to the bucket 15 as at 80. The bucket 15 is also pivotably connected to the dipper stick 16 as at 81. Thus, a four element linkage is provided for regulating the angular disposition of the bucket 15.

Elevating or lowering the bucket is conveniently achieved by the retraction or extension of the piston rod 1% of the unit 19. The unit 19 is seen to be interconnected between the pivot point 79 on the dipper stick 16 and the extreme upper end 82 of the boom 17. The dipper stick 16 is pivotably connected to the boom 17 at 83 which is intermediate the pivot point 82 and the lower boom pivot point 84.

The angular disposition of the boom 17 relative to the ground is achieved through extension or retraction of the piston rod 29a (again see FIG. 2) which at its upper end is pivotably connected to the boom 17 as at 85, the pivot point 85 being below the pivot points 82 and 83 and generally aligned therewith. As the back hoe 14 is operated, through the extension or retraction of the just previously described cylinder and piston rod units 18-, 19 and 20, the stresses developed thereby are effectively transmitted to the main frame 22. The main frame 22 is equipped with a rigid section rearwardly and a rigid section forwardly. These two sections are essentially spaced from each other and the intermediate portion is relatively unbraced to permit a degree of flexing, the intermediate portion being denoted by the letter F in FIG.

7 4. This flexing is limited to within the elastic limit of the elements employed.

Reference to FIG. 3 reveals that a light cross member 86 extends between the

longitudinal members

42 and 43 in this heretofore described embraced length F. The member 86 is a fiat metal member relatively incapable of providing reinforcement and is employed as a mounting for the brake system of the apparatus 10. Extending between the member 86 and the transverse channel 66 are a pair of plates 87 employed for the mounting for other apparatus controls.

While in the foregoing specification we have set forth a detailed description of an embodiment of the invention for the purpose of explanation thereof, many variations of the details herein given may be made by those skilled in the art Without departing from the spirit and scope of the invention.

We claim:

1. An earth handling machine, comprising a generally rectangular frame, said frame including transverse mem' bers at the front and rear ends of the machine connected with longitudinal members, front and rear axles mounted on said frame extending transversely below thereof, said rear axle being spaced from the rear transverse member, diagonal buttress members extending between said longitudinal members adjacent said rear axle and said rear transverse member to provide a generally rigid rear section, a back hoe pivotally mounted on said rigid rear section, a motor mounted on said longitudinal members and said front transverse members to provide a generally rigid front section, said front and rear sections being spaced apart to provide a relatively unbraced intermediate portion in each of said longitudinal members adapted to flex under loads applied to either end so as to prevent the development of localized stress points but insufficient to exceed the elastic limit of said intermediate portion, said motor being mounted on said longitudinal members at a spaced distance from said front member, a column member on each longitudinal member adjacent the motor mounting thereon, a loader arm pivotally mounted on each column member at a spaced distance above the longitudinal member associated therewith, a beam member interconnecting said column members adjacent the mounting of said load arms, a bucket pivotally connected between said load arms remote from said column members, and a cylinder and piston rod unit interconnected between each load arm and its associated longitudinal member.

2. An earth handling machine, comprising a generally rectangular frame, said frame including:

(A) transverse members at the front and rear ends of of the machine connected with longitudinal mem bers,

(B) front and rear axles mounted on said frame extending transversely below thereof, said rear axle being spaced from the rear transverse member,

(C) diagonal buttress members extending between said longitudinal members adjacent said rear axle and said rear transverse member to provide a generally rigid rear section,

(1) said buttress members including a pair of buttress members extending between each longitudinal member and said rear transverse member, the buttress members in each pair being vertically spaced apart, with the lower of each pair of members being shorter than the upper,

(D) a back hoe pivotally mounted on said rigid rear section,

(E) a motor mounted on said longitudinal members and said front transverse members to provide a generally rigid front section,

(1) said motor being mounted on said longitudinal members at a spaced distance from said front member,

(F) said front and rear sections being spaced apart to provide a relatively unbraced intermediate portion in each of said longitudinal members adapted to flex under load applied to either end so as to prevent the development of localized stress points, but insuflicient to exceed the elastic limit of said intermediate portion,

(G) a column member on each longitudinal member adjacent the motor mounting thereon,

(H) a load arm pivotally mounted on each column member at a spaced distance above the longitudinal member associated therewith,

(I) a beam member interconnecting said column members adjacent the mounting of said load arms,

(I) a bucket pivotally connected between said load arms remote from said column members, and

(K) a cylinder and piston rod unit interconnected between each load arm and its associated longitudinal member.

3. The machine of claim 2 in which stabilizing members are mounted on said rigid rear section in general transverse alignment with said rear transverse member and below said longitudinal members.

4. An earth handling machine, comprising a generally rectangular frame, said frame including:

(A) transverse members at the front and rear ends of the machine connected with longitudinal members,

(D) a back hoe pivotally mounted on said rigid rear section,

(1) said diagonal buttress members being coupled through said rear transverse member adjacent the pivotal mounting of said back hoe,

(2) said back hoe including (a) a boom pivotally mounted at one end thereof on said transverse member,

(b) a dipper stick pivotally mounted at one end thereof on said boom adjacent to but spaced from the other end of said boom,

(0) a bucket pivotally mounted on the other end of said dipper stick,

(d) a cylinder and piston rod unit interconnected between said boom at the other end thereof and said dipper stick, and

(e) a second cylinder and piston rod unit interconnected between said dipper stick and said bucket,

(F) said front and rear sections being spaced apart to provide a relatively unbranched intermediate portion in each of said longitudinal members adapted to flex under load applied to either end so as to prevent the development of localized stress points, but insufiicient to exceed the elastic limit of said intermediate portion,

9 10 (I) a beam member interconnecting said column memand stabilizer means mounted on said frame for movebers adjacent the mounting of said load arms, ment through a vertical are adjacent and parallel to said (J) a bucket pivotally connected between said load plate.

arms remote from said column members, and

(K) g i' Piston unit iPtel'conneQted 6 References Cited in the file of this patent figillljeidc oa arm and 1ts associated longitudinal UNITED STATES PATENTS 5. The machine of claim 4 in which said

rear transverse

2,3 19,921 Dooley et a1 May 25, 1943 member includes a plate extending vertically downward 2,768,499 Pilch Oct. 30, 1956 a spaced distance below said longitudinal members, said 2,817,448 Pilch Dec. 24 1957 plate providing a pair of vertically spaced bearings for 10 2,84 9 Sonnemfill et g- 5, 1958 the pivotal mounting of said boom, said plate, at its trans- 2,878,951 Pilch Mar. 24, 1959 verse edges, providing pivotal mounts for stabilizer means, 2,890,805 Pilch June 16, 1959