CA1102748A - Load handling vehicle - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A lift truck has a log handling carriage head carried by a verti-cally movable boom. The boom is pivoted to the truck frame below the opera-tor's cab to provide a clear line of sight from the cab along the top of the boom to the carriage head in any position of the boom. The carriage head com-prises a pair of independently operable, vertically disposed, transversely separated, articulated claws. The claws are pivoted to opposite side exten-sions of the outer end of the boom for improved visibility to the load. Each claw includes a generally upstanding main carriage member, a fork extending forwardly from a lower end of such member, and a tusk curving forwardly and downwardly from the upper end of such member. The fork and main carriage member of each claw pivot about a common transverse axis, and the vertical angle of each fork is adjustable independently of the other by pivoting its associate main carriage member independently of the other such member. Each fork is free floating within limits relative to its main carriage member so that when the fork contacts the ground, its main carriage member may be piv-oted without moving the fork. A tandem hydraulic cylinder and crank mechanism pivots each tusk relative to its main carriage member between open and closed positions. Each tusk is operable independently of the other.

Description

~1~3;~7~8 The present application is a divisional of Copending application serial No. 306192, filed June 26th, 1978.
The present invention relates to lift trucks, and more particular-ly to lift trucks having boom-or-mast-supported claw-type handling elements with forks for handling elongate loads such as logs.
Existing load handling vehicles, such as the one shown in United States Patent 3,669,293, issued June 13, 1972, of inventors Darrel L. Bryan and Larry D. Malsch, typically have a pair of vertically disposed, laterally spaced apart, articulated claws pivoted to a boom.
However, the claws of known prior art load handling vehicles are interconnected and driven so that they operate only synchronously, not in-dependently~ Therefore, the claws of such vehicles cannot be manipulated independently of one another and the load handling capability of such vehicles is thereby limited.
Furthermore, the forks of both claws of such prior vehicles always remain parallel to each other. This makes it difficult to insert these forks under a load unless the load happens to be parallel to the plane of the forks.
Consequently, it is hard to insert the forks under and pick up skewed or otherwise uneven loads such as logs in a haphazard pile. In addition, with such vehicles, it i5 difficult to unload logs onto a surface which is not parallel to the forks, such as the sloping bunks of a log truck parked on a hill. This occurs because each of the claws cannot be independently pivoted to adjust the attitude of each fork so that the load is approximately parallel to the support surfaces onto which it is to be loaded.
The claws of some prior load handling vehicles include a pivoted upstanding main carriage member, a lower forwardly extending fork member for supporting a load and an upper forwardly extending tusk which can be pivoted .

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l~&~Z748 to grasp a load. However, limitations in the connection between the fork and main carriage member require that such members always maintain a constant an-gular relationship and prevent manipulation of the main carriage member while its fork remains stationary and supported from below. Therefore, the main carriage members and tusks cannot be used to reach forwardly and pull a load onto the forks while the forks remain supported in stationary positions to re-ceive the load.
Moreover, although the tusks of some prior load handling claws are known to be pivoted independently of one another, the arcs through which such tusks can be pivoted are typically limited because of limitations of the tusk pivoting mechanism. For this reason, the tusks of such vehicles cannot be pi-voted to grasp both very small and very large loads.
Furthermore, the boom or mast structure, the carriage heads, and hydraulic mechanisms of existing load handling vehicles commonly obstruct the line of sight from the operator to the load.
Load handling vehicles and carriage heads illustrative of the known prior art and of the foregoing problems are disclosed in: United States Patent No. 3,669,293, as described above; United States Patent No. 2,997,193, issued August 22, 1961, of inventor Elmer J. Dunham; United States Patent No. 3,275,173, issued September 27, 1966, of inventors Keith W. Kampert and Richard F-Zimmerman; United States Patent No. 3,125,234, issued March 17, 1964, of inven-tor Charles W. Gustine; United States Patent No. 3,182,833, issued May 11, 1965, of inventor Le Grand H. Lull; United States Patent No. 2,958,434, issued November 1, 1960, of inventor Eddie B. Wagner; United States Patent No.
3,352,442, issued November 14, 1967, of inventor John E. Magnuson; United States Patent No. 3,034,821, issued May 15, 1962, of inventors Theodore N.
Hackett, James E. Raven and Daniel M. Schwartz; and United States Patent No.

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3,817,567, issued June 18, 1974, of inventor Le Grand H. Lull.
The present invention provides, for use with a vehicle comprising a main frame, and an operator'Sstation on the frame, a load handling apparatus comprising boom means pivotally connected at one end to the frame for movement about a pivot axis in a generally vertical plane.
~ oom operating means are provided, for raising and lowering the boom means about the pivot axis. The boom means comprises a rigid one-piece boom, centered longitudinally between opposite sides of the frame and including a longitudinally straight boom top surface extending unobstructed from the pivotally connected end of the boom to a downturned free end portion thereof.
The boom is adapted to be pivotally connected to the frame forwardly of the operators station and at an elevation sufficiently low to provide lines of sight from the station forwardly along and above the boom top surface. The boom includes a pair of boom side extensions extending equidistant in opposite directions laterally from opposite sides of the downturned free end portion of the boom.
A pair of generally vertically disposed laterally spaced apart ar-ticulated claw means, each claw means defining a load receiving opening and being operable to open to admit a load within the opening and close to grasp a load within the opening, is pivoted one to the laterally outer end of each boom side extension for movement of the pair in generally vertical parallel planes which are parallel to and spaced equidistant on opposite sides of the generally vertical plane of movement of the boom.
Claw operating means are provided for pivoting and opening and closing the pair of claw means in their respective vertical planes, the claw operating means being positioned generally in the vertical planes of movement of the claw means so as to maintain the space between the pair of claw means ' free of obstructions. The claw means are spatially and mechanically separated from each other and connected to the boom only at the level of the boom side ex~ensions, such that the boom side extensions, the claw means with their as-sociated operating means, and the boom define the limits of unobstructed view corridors from the operators station to a load supported by and extending be-tween the pair of claw means, a first such corridor extending centrally between the pair of claw means along the boom top surface and second and third such corridors extending along the boom into spaces between the opposite sides of the pair of claw means at the free end portion.
10 Preferably, the boom means comprises a straight rigid boom, which is hollow and comprises a planar top wall, a pair of vertical spaced apart side walls and a bottom wall, the boom being connected to the frame at a po-sition such that an operator in the operator'sstation has a clear line of sight to the claw means along the top wall in all operating positions of the boom.
The vehicle may include claw pivoting means for pivoting each of the claw means about its pivotal connection with the associated boom side ex-tension, the claw pivoting means being positioned so that the line of sight through each view space is not obstructed.
In the accompanying drawings, which illustrate an exemplary embodi-ment of the present invention:
Figure 1 is a side elevational view of a preferred embodiment of aload handling vehicle in accordance with the invention;
Figure 2 is a front elevational view of the load handling vehicle of Figure 1 as viewed from line 2-2 of Figure l;
Figure 3 is a side elevational view of the carriage head portion of the vehicle of Pigure 1 on an enlarged scale;
Figure 4 is a sectional view taken along line 4-4 o`f Figure 3;

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Figure 5 is a partial sectional view taken along line 5-5 of Figure 3;
Figure 6 is a sectional view taken along line 6-6 of Figure 3;
Figure 7 is a top plan view of the carriage head as viewed from line 7-7 of Figure 3 with a lower portion of the head deleted for clarity; and Figure 8 is a side elevational view of the carriage head portion of the load handling vehicle of Figure 1, but in a different position of ad-justment than that shown in Figure 3.
It should be clearly understood that the invention is described for the sake of clarity, in the environment of the invention claimed in the aforementioned application No. 306192.
Referring to Figures 1 and 2, the load handling vehicle includes a self-propelled main frame 2 supported on a pair of driven front wheels 4 and a pair of side by side steerable rear wheels 6, only one being shown. An operator's station such as cab 8 is approximately centered between the opposite ends and sides of frame 2.
A boom means 10 extends forwardly from frame 2 and is pivoted to the frame just in front of cab 8 for vertical movement about a boom pivot shaft 11. Pivot shaft 11 extends between a pair of laterally spaced, upright 20 boom support trunnions 12, 14. Boom 10 is connected to the frame below cab window 16 and therefore below the level of the operator in the operator's station. When connected in this manner the operator always has a line of sight along the top of the boom to the load being handled when the boom is raised and lowered. Frame 2 is sloped downwardly toward the front of the ve-hicle from trunnions 12, 14 to provide clearance for vertical movement of the boom.
Boom 10 comprises a straight, single-section boom of rigid, hollow, . . , - - -. . . ~ . . :

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box-like structure formed by a pair of vertical side walls 24, 26, a bottom wall 28, and a top wall 29. At the outer or free end of the boom, side walls 24, 26 are enlarged and extend downwardly to form a generally wedge-shaped en-larged end portion 32. An end plate 34, best seen in Figure 2, closes the outer end of the boom.
Boom side walls 24, 26 also project upwardly at the outer end of the boom beyond top wall 29 to form laterally spaced guard plates 36, 38.
These guard plates prevent material from sliding down the boom toward the cab when the boom is in a raised position. The guard plates are offset laterally from the center line of the boom (Figure 2) so as to not obstruct the line of sight along the top of the boom.
A boom operating means is provided for pivoting the boom about shaft 11. Such means comprises a pair of side by side hydraulic cylinders 40, 42. Each cylinder is pivoted at one end to frame 2 at 44, below boom pivot shaft 11, and at the opposite end to an outer portion of the boom at 46.
A carriage head indicated generally at 58 is supported by a car-riage head support means comprising boom side extensions 60, 61 projecting laterally from the bottom of enlarged boom end portion 32. A pair of boom stabilizer tubes 62, 64 on opposite sides of the boom extend from boom pivot shaft ll to boom side extensions 60, 61 respectively. These boom stabilizer tubes rigidify boom 10, particularly against lateral deflection and twisting under load.
As shown in Figures 1 and 2, carriage head 58 includes a pair of articulated claw means 66, 68, one pivotally carried by each of the opposite boom side extensions 60, 61. The claws are generally vertically disposed, laterally spaced apart and symmetrical about the center line of boom 10.
A view space 70 ~Figure 2) is formed between claw 66 and side wall .. - , - . - , ~

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24 of the boom and is bounded on the bottom by an upper surface of boom side extension 60. A view space 72 is similarly defined on the opposite side of the boom by side wall 26~ claw 68 and the upper surface of side extension 61.
The width of view spaces 70, 72 is substantial and is approximately equal to the width of the boom. The operator of the vehicle has a clear line of vision through each of these view spaces along the side walls 24, 26 of the main boom to the load being handled.
With reference to Figure 1, claw 66 defines load receiving opening and is composed of a main carriage means or member 82, a fork means or member 86, and a tusk means or member 90. Main carriage member 82 is pivotally car-ried by boom side extension 60 for movement in a generally vertical plane to pivot the claw. Fork member 88 is als-o pivotally carried by boom side exten-sion 60 and extends forwardly of a lower portion of main carriage member 82 for supporting a load within the load receiving opening. Tusk member 90 is pivotally connected to an upper portion of the main carriage member for move-ment in a generally vertical plane between an open position to admit a load within the opening and a closed position to grasp a load on the fork member within the opening. Claw 68 defines a separate load receiving opening and is identical to claw 66, having a corresponding main carriage member 84, fork member 88 and tusk member 92.
As best seen in Figure 7, the main carriage members are each formed by a pair of generally upstanding, parallel laterally spaced main carriage side plates 94, 96 interconnected by cross-members (not shown). The side plates are ~urved forwardly at their upper portions and are joined together at their lower ends by a cylindrical sleeve portion 152 (Figure 5).
Each fork includes a pair of parallel laterally spaced apart fork arms 126, 128 ~Figure 6) forming a slot 132 between them. The arms of each .. . . . .. :
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. : ,: : - -fork are joined together at an outer end by a plate 130. As shown in Figure 3, each fork arm is generally straight from its outer end throughout the major portion of its length but has an upwardly extending portion 129 at its inner end with a large hole therethrough for mounting purposes.
Each tusk 90, 92 includes a pair of rigid laterally spaced apart side plates 212,213 (Figure 7) joined together at their outer ends at 216.
Reinforcing plates 220, 222 are welded to the inner end portions of side plates 212, 213 to strengthen the tusks at their connections to the main carriage members. Cross members (not shown) interconnect side plates 212, 213 to ri-gidify the tusk. ~ach tusk is symmetrical about a vertical median plane bi-secting the associated main carriage member and fork. Therefore, as shown in phantom in Figure 1, when the tusks are pivoted clockwise to close the load receiving opening the outer end 216 of each tusk enters slot 132 of its assoc-iated fork. During further clockwise pivoting, the tusk is guided in the slot and braced by the fork arms against any load-imposed lateral deflection or twisting out of its plane of motion.
As shown in Fi~ure 6, the claws are pivoted to the opposite ends of a pivot tube 104 which extends perpendicularly to boom 10 through boom side extensions 60, 61 and projects beyond the outher ends of these side ex-tensions. Pivot tube 104 thereby provides a common transverse generally hori-zontal axis about which the claws are free to pivot independently of one another.
The details of the connection of the main carriage and fork com-ponents of claw 66 to pivot tube 104 are shown in Figure 5. Since the con-nection of claw 68 to such tube is identical, it will not be described in de-tail. A flanged sleeve 148 is formed at the outer end of boom side extension 60 to limit inward movement of claw 66 along the pivot tube. As pre~iously . .

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mentioned, cylindrical sleeve 152 forms the lower end of main carriage member 82. Sleeve 152 is mounted for rotation on pivot tube 104 and carries annular internal bearings 160, 162 on its flange extensions 154, 156 for this purpose.
Fork arms 126, 128 are mounted for rotation on the outside of flange exten-sions 154, 156 respectively, and carry annular flange bearings 168, 170. A
collar 176 bolted to pivot tube 104 retains the fork and main carriage assembly on the pivot tube. Annular thrust bearings 188, 190 on the fork arms separate the fork arms from the main carriage side plates and facilitate relative rota-tion therebetween. Additional thrust bearings 192, 196 on the fork arms, a collar bearing 200 and a bearing 198 on flanged sleeve 148 facilitate rotation of the fork and main carriage member on the pivot tube. Annular shim 194 re-duces the lateral play of the fork and main carriage member along the pivot tube and determines their exact position on the tube.
A fork restraining means, such as the fork stops 134 of Figure 3 are mounted to the outer surface of the main carriage side plates. Such stops are positioned to engage the upwardly extending inner end portions 129 of the fork arms to limit the free-floating pivoting movement of the forks. The center of gravity of each of the forks is forward of pivot tube 104 so that whenever the forks are unsupported from below, they pivot clockwise to engage the fork stops. When in unsupported engagement with the fork stops, the forks pivot with their main carriage members. However, as shown in Figure 8 and in phantom in Figure 3, the forks are free to pivot counterclockwise away from their stops. This enables pivoting movement of the main carriage members in-dependently of their forks within limits when the forks are supported from be-low.
When connected as described, fork 86 and main carriage member 82 pivot about claw pivot tube 104 in a common generally vertical plane. Similarly, _g _ .
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-- , --fork 88 and its main carriage member 84 pivot about the pivot tube in another common generally vertical plane.
Tusk 90 and main carriage member 82 are pivotally interconnected by a tusk pivot tube 208. The details of this interconnection are shown in Figure 4 and described below. Tusk 92 and main carriage member 84 are identi-cally connected together by a tusk pivot tube 210 (Figure 1) and will not be described in detail. Tusk pivot tube 208 is pivotally carried by the upper end of main carriage side plates 94, 96 in annular bearings 298, 300.
A crank means 234 is mounted on pivot tube 208 between carriage side plates 94, 96. Such crank includes a pair of laterally spaced crank arms 236, 238 joined at their lower ends by a cylindrical sleeve portion 262 rotatably mounted on the pivot tube in bearings 266, 268. The inner end por-tions of tusk side plates 212, 213 are rotatably mounted on pivot tube 208 in bearings 302, 304 outwardly of the main carriage side plates. End collars 284 bolted to the opposite ends of the pivot tube retain the tusk, main car-riage and crank assembly centered on such tube so that such assembly is sym-metrical about a vertical median plane bisecting the tusk and main carriage member 82. Thrust bearings 306, 308 separate the collars from the tusk side plates. Similar thrust bearings 310, 312 and 314, 316 separate the tusk side plates from the main carriage side plates, and the main carriage side plates from the crank arms 236, 238.
Tusk restraining means in the form of tusk stops 258 of Figure 3 mounted to the outer surfaces of the main carriage side plates are engageable with the inner ends of the tusk side plates to limit pivoting movement of the tusks in an opening direction. Clearance is provided between the crank and tusk side plates to prevent the crank from interfering with the pivoting move-ment of the tusk.

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Means are provided for pivoting each of the main carriage members independently of one another. Such means comprise a pair of hydraulic carriage cylinders 110, 112 ~Figure 1) one for each main carriage member. Cylinder 110 is pivotally connected at one end to a cylinder support arm 114 ~Figure 3) which in turn is rigidly connected to boom side extension 60 and projects up-wardly therefrom. The opposite, or rod, end of cylinder 110 extends between rear flange extensions 118 of side plates 94, 96 and is pivoted to a pin 122 extending between such flanges. Cylinder 112 is similarly connected at one end to a cylinder support arm 116 (Figure 6) on side extension 61 and at its opposite end to its main carriage member 84. Cylinders 110) 112 cause their associated main carriage members to pivot forwardly when each cylinder is ex-tended When connected in this manner, cylinders 110,112 are operable to pi-vot their main carriage members and connected claw members through an arc of approximately 65.
Tusk operating means, comprising a pair of identical tandem cy-linder tusk operating mechanisms, one for each tusk, are shown best in Figures 3 and 7. Each tusk operating mechanism includes a first hydraulic cylinder 230, second hydraulic cylinder 232, and crank 234. The rod end of cylinder 230 is pivoted to tusk 90 by a pin 240 extending between tusk side plates 212, 213. Spacers 242, Z44 on pin 240 center the rod between the side plates.
The opposite end of cylinder 230 is pivoted to crank 234 by a pin 246 extend-ing between crank arms 23G, 238. One end of second cylinder 232 is pivoted to main carriage member 82 by a pin 254 which extends between ears 250,252 on the main carriage side plates. The rod end of cylinder 232 is pivoted to crank 234 by a pin 256 extending between the crank arms.
When cylinder 230 extends as viewed in Figure 3, tusk 90 pivots clockwise on tusk pivot tube 208 toward its fork 86 and a closed position :

because cylinder 232 holds crank 234 in a fixed position. When cylinder 232 extends, tusk 90 pivots further in a clockwise direction toward another closed position to make the load receiving opening within the claw even smaller than before. This happens because cylinder 230 now holds crank 2~4 in a fixed posi-tion. When connected in this manner, cylinders 230 and 232 can pivot tusk 90 through a total arc of approximately 180, each cylinder contributing about 90 to the total arc of movement.
The large arc through which the tusks can pivot increases the cap-ability of the vehicle to handle loads of widely varying size. Thus, when the tusk is pivoted to its maximum closed position ~see Figure 1), the tusk can grasp a load having a small diameter, such as a single log, and hold it against the main carriage member and fork. Conversely, when opened fully, the tusk provides a maximum opening for receiving large diameter loads such as a truck-load of logs. This wide open posi~ion of the tusks is also useful when, as shown in Figure 8, the fork is supported from below and the main carriage mem-ber is pivoted forwardly to extend the tusks beyond a load. The tusks and carriage members can then be worked to pull the load onto the forks.
The cylinders connected to each claw are positioned generally in the vertical plane containing the connected claw so that they do not obstruct view spaces 70, 72. Therefore, the arrangement of the claws and cylinders in-creases the visibility of the work area surrounding the vehicle so that the vehicle is safer to operate. In addition, the visibility of the load to the operator is enhanced.
All of the hydraulic cylinders of the load handling vehicle are supplied with pressure fluid from a source on frame 2 through conventional hydraulic circuitry.
The controls ~not shown) for the hydraulic circuitry are located .

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in cab 8. The controls include a control mechanism for controlling the opera-tion of each cylinde~ of each claw independently of one another and independ-ently of the cylinders of the other claw. In addition, to optimize load handling speed when independent manipulation of the claws is not necessary, the controls may include a single wobble stick for simultaneous operation of both claws and the boom. In one version, when the wobble stick is pushed for-wardly, the boom descends and when pulled back the boom ascends. Pushing the wobble stick laterally to the left pivots both main carriage members forwardly about their pivots simultaneously. Pushing the wobble stick laterally to the right pivots both main carriage members rearwardly about their pivots simul-taneously. When a button on top of the wobble stick is pushed, both tusks close fully on the load as far as possible to grip the load securely. By mov-ing the stick in the four diagonal directions, raising and lowering of the boom occurs simultaneously with the pivoting of both main carriage members. For ex-ample, pushing the wobble stick in the diagonal direction between the forward and left positions simultaneously raises the boom and pivots both main carriage members forwardly. Therefore, for many operations~ the operator can control movement of the boom and claws with one hand, while the other hand is free to steer the vehicle.
Operation Figure 1 shows a load handling vehicle with the claws disposed in different positions of adjustment. Further positions of the claws are shown in phantom to demonstrate the independence of manipulation of each claw.
In handling a load, such as in loading a log truck, the boom is raised so that the forks are off the ground and the lift truck approaches the logs to be loaded with its tusks open. The main carriage members are pivoted to adjust the attitude of the forks with respect to that of the logs so that ., ~
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the forks can be inserted under the logs. With the forks beneath the logs, the tusks are pivoted to a closed position, dragging logs into the claw open-ing and finally holding the captured truck load of logs firmly on the forks and against the main carriage members. With the claws remaining closed, the ; boom is raised. At the same time the claws may be pivoted upwardly to bring the center of gravity of the load closer to the boom. ~le lift truck with its truck load of logs approaches the log truck, which may be parked on an incline so that its bunks are not parallel to the load of logs. Consequently, the claws are independently pivoted until the attitude of the forks, and hence the load of logs, is approximately parallel to the bunks. The boom is then lower-ed and at the same time the claws are pivoted downwardly. The tusks are open-ed to release the logs onto the truck. The lift truck then approaches addi-tional logs for loading.
With reference to Figure 8, after approaching the logs with the tusks open, the boom may be lowered until the forks are supported from below by the ground or other logs. The main carriage members are then pivoted for-wardly to move the tusks to a position forwardly beyond the logs. The tusks are then pivoted toward a closed position and at the same time the main car-raige members are pivoted rearwardly so that the logs are pulled or dragged ~-onto the forks. When supported from below, the forks will tend to remain stationary when the main carriage members and tusks are manipulated to drag the logs onto the forks. For this reason, a log which has been dragged onto the forks will tend to remain in an undisturbed position on the forks even though the main carriage members and tusks are then operated to pull additional logs onto the forks.
While this load handling apparatus has been described in an embodi-ment wherein a carriage head is mounted to a boom, the invention may also take " -, ' ' forms wherein the carriage head is mounted on other types of load lifting mem-bers. For example, the carriage head could be carried by the vertically mov-able element of a conventional lift truck mast.

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Claims (6)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. For use with a vehicle comprising a main frame and an operator's station on said frame, a load handling apparatus comprising;
boom means adapted to be pivotally connected at one end to the frame for movement about a pivot axis in a generally vertical plane;
boom operating means for raising and lowering said boom means about said pivot axis;
said boom means comprising a rigid one-piece boom adapted to be centered longitudinally between opposite sides of said frame and including a longitudinally straight boom top surface extending unobstructed from the piv-otally connected end of said boom to a downturned free end portion thereof, said boom being adapted to be pivotally connected to said frame forwardly of said operator's station and at an elevation sufficiently low to provide lines of sight from said station forwardly along and above said boom top surface, said boom including a pair of boom side extensions extending equi-distant in opposite directions laterally from opposite sides of said down-turned free end portion of said boom;
a pair of generally vertically disposed laterally spaced apart articulated claw means, each claw means defining a load receiving opening and being operable to open to admit a load within said opening and close to grasp a load within said opening, said pair of claw means being pivoted one to the laterally outer end of each said boom side extension for movement of said pair in generally vertical parallel planes which are parallel to and spaced equi-distant on opposite sides of the generally vertical plane of movement of said boom;

claw operating means for pivoting and opening and closing said pair of claw means in their respective vertical planes, said claw operating means being positioned generally in the vertical planes of movement of said claw means so as to maintain the space between said pair of claw means free of obstructions, said pair of claw means being spatially and mechanically separated from each other and connected to said boom only at the level of said boom side extensions such that said boom side extensions, said claw means with their associated said operating means and said boom define the limits of unobstructed view corridors from said operator's station to a load supported by and extend-ing between said pair of claw means, a first such corridor extending centrally between the pair of claw means along said boom top surface and second and third such corridors extending along said boom into spaces between the oppo-site sides of said pair of claw means at said free end portion.

2. The load handling apparatus of claim 1 wherein said boom means comprises a straight rigid boom, said boom being hollow and comprised of a planar top wall, a pair of vertical spaced apart side walls and a bottom wall, said boom being connected to the frame at a position such that an operator in said station has a clear line of sight to said claw means along said top wall in all operating positions of said boom.

3. The load handling apparatus of claim 1 including claw pivoting means for pivoting each of said claw means about its pivotal connection with said associated boom side extension, said claw pivoting means being positioned so that the line of sight through each view space is not obstructed.

. 4. A load handling vehicle comprising:
a main frame;

an operator's station on said frame;
boom means pivotally connected at one end to the frame for move-ment about a pivot axis in a generally vertical plane;
boom operating means for raising and lowering said boom means about said pivot axis;
said boom means comprising a rigid one-piece boom centered long-itudinally between opposite sides of said frame and including a longitudinally straight boom top surface extending unobstructed from the pivotally connected end of said boom to a downturned free end portion thereof, the pivotal connec-tion of said boom to said frame being positioned forwardly of said operators station and at an elevation sufficiently low to provide lines of sight from said station forwardly along and above said boom top surface, said boom including a pair of boom side extensions extending equidistant in opposite directions laterally from opposite sides of said down-turned free end portion of said boom;
a pair of generally vertically disposed laterally spaced apart ar-ticulated claw means, each claw means defining a load receiving opening and being operable to open to admit a load within said opening and close to grasp a load within said opening, said pair of claw means being pivoted one to the laterally outer end of each said boom side extension for movement of said pair in generally vertical parallel planes which are parallel to and spaced equi-distant on opposite sides of the generally vertical plane of movement of said boom;
claw operating means for pivoting and opening and closing said pair of claw means in their respective vertical planes, said claw operating means being positioned generally in the vertical planes of movement of said claw means so as to maintain the space between said pair of claw means free of obstructions, said pair of claw means being spatially and mechanically sepa-rated from each other and connected to said boom only at the level of said boom side extensions such that said boom side extensions, said claw means with their associated said operating means and said boom define the limits of unobstructed view corridors from said operator's station to a load supported by and extend-between said pair of claw means, a first such corridor extend-ing centrally between the pair of claw means along said boom top surface and second and third such corridors extending along said boom into spaces between the opposite sides of said pair of claw means at said free end portion.

5. The load handling vehicle of claim 4 wherein said boom means comprises a straight rigid boom, said boom being hollow and comprised of a planar top wall, a pair of vertical spaced apart side walls and a bottom wall, said boom being connected to the frame at a position such that an operator in said station has a clear line of sight to said claw means along said top wall in all operating positions of said boom.

6. The vehicle of claim 4 including claw pivoting means for pivot-ing each of said claw means about its pivotal connection with said associated boom side extension, said claw pivoting means being positioned so that the line of sight through each view space is not obstructed.