Material handling machine

A self-propelled, low profile material-handling vehicle mounted on a pair of front wheels and a pair of rear wheels. The vehicle supports an extendible boom rotatable around a horizontal pivot axis that is substantially located above the rear wheels. A cab for a driver is located on one side of the boom, and a load-carrying platform is located on the side of the boom opposite the cab. A well located in the vehicle body between the cab and the load-carrying platform is positioned lower than the pivot axis of the boom and is arranged to receive the boom when it is pivoted downward toward the front wheels so that a load can be maneuvered below grade level. The pivot axis is vertically located above the top of the wheels and below the top of a steering wheel located within the cab so that the driver's vision is substantially unobstructed when a load is carried by the boom close to the grade level.

.Iadd.REFERENCE TO RELATED APPLICATION 
This is a Reissue Application of our U.S. Pat. No. 3,836,025, dated Sept. 
17, 1974. .Iaddend. 
BACKGROUND OF THE INVENTION 
This invention relates to self-propelled, material-handling vehicles, and 
more particularly relates to such vehicles which employ an extendible 
boom. 
Over the past decade, experience has revealed the need for a 
material-handling vehicle which can be used in the construction, 
manufacturing and warehousing industries. Such a vehicle must have the 
reach capability of a conventional overhead crane and the maneuverability 
and compactness generally attributed to a conventional fork lift truck. In 
order to be useful, such a vehicle must have a boom capable of raising a 
heavy load to the top of a multi-story building and must have a low 
profile and short wheel base that enable operation within a warehouse or 
stock-piling yard. 
In the past, vehicles capable of lifting heavy loads to a substantial 
height have not been capable of also performing as a conventional fork 
lift truck. One such prior art machine comprises a vehicle body mounted on 
wheelbearing front and rear axles. A cab for a driver is centrally located 
over the front axle, and a boom is rotatably mounted on a pivot axis 
located substantially over the rear axle and above the top of the cab so 
that the boom extends forward over the cab. A fork is attached to a 
support member that extends in front of the cab and is connected to the 
free end of the boom. An engine which powers the vehicle is located over 
the rear axle, and the major portion of the engine is located above the 
rear wheels. 
While such a vehicle is capable of lifting loads to a substantial height, 
the vehicle is relatively useless in an environment requiring small size 
and unimpaired visibility by the driver, such as a warehouse. The mounting 
of the boom above the cab creates a vehicle which is too high to go 
through many warehouse archways, and the support member extending in front 
of the cab impairs the vision of the driver. Moreover, the vehicle has a 
relatively high center of gravity which increases the moment arm created 
around the front axle during deceleration of the vehicle, such as during 
braking. When the vehicle is carrying a heavy load on the fork, this 
moment arm tends to pitch the vehicle forward and to lift the rear wheels 
off the ground during braking. The problem is accentuated when the boom is 
extended to any substantial extent. As a result of this deficiency, the 
vehicle tends to be unstable when it is maneuvered with a heavy load. 
In addition to the foregoing deficiencies, the vehicle provides no means 
for simultaneously carrying a load on the fork and a portion of the 
vehicle body. This deficiency limits the physical size of the load which 
can be safely carried by the vehicle. The vehicle also is not capable of 
maintaining a load at the same elevation above the ground level as the 
boom is extended and retracted. This deficiency limits the ability of the 
driver to conveniently maneuver a load. In addition, the position of the 
boom over the cab of the vehicle prevents the boom from extending into an 
excavation so that a load may be maneuvered below the grade level. 
SUMMARY OF THE INVENTION 
In order to overcome the deficiencies of the prior art vehciles, the 
applicants have invented a unique and versatile vehicle having attributes 
of both an overhead construction crane and a fork lift truck capable of 
relatively high speed maneuverability in confined areas. By arranging the 
components of the vehicle in a unique manner, the applicants are able to 
substantially reduce the center of gravity, thereby increasing the weight 
of a load which may be safely maneuvered by the vehicle during 
deceleration. Moreover, by providing a well in the vehicle body and by 
strategically placing a boom over the well and between a driver's cab and 
load-carrying platform, applicants have been able to create a vehicle 
capable of maneuvering a load below grade level and of carrying a load 
close to the ground without impairing the vision of a driver operating the 
vehicle. 
According to another feature of the invention, the boom mounted on 
applicant's vehicle employs a unique extending and retracting mechanism 
which provides smooth and trouble-free operation at minimum cost. 
According to another feature of the invention, a fork is located on the 
front of the boom and means are provided for pivoting the fork so that a 
load can be simultaneously carried on the fork and on the load-carrying 
portion of the vehicle body. In addition, a drop block is simultaneously 
carried on the boom adjacent the fork so that a load can be handled by 
either the fork or the drop block, or both. 
According to another feature, the vehicle is provided with means for 
maintaining the drop block hook a constant height above the grade level as 
the boom is extended and retracted so that the maneuverability of a load 
held by the drop block is increased. In addition, a control system 
maintains the fork at the same relative attitude with respect to the 
ground as the boom is raised and lowered.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings, a preferred form of vehicle 12 embodying the 
present invention basically comprises a body 14, an axle and wheel 
assembly 60, a suspension assembly 110, a cab 124, a pivot assembly 150, a 
boom assembly 164, a boom extending assembly 206, a hoisting assembly 244, 
and a load-carrying assembly 250. 
Referring to FIGS. 1-3, 10 and 12, body 14 comprises a load-carrying 
platform 16 having a flat, horizontal, upper surface 18. The underside of 
the vehicle is protected by a right-hand depending shield plate 19 
attached to the underside of platform 16. The vehicle has a left front 
fender 20 and a left rear fender 22 that are joined by a platform 24 which 
forms the floor of cab 124 (FIG. 10). 
Referring to FIGS. 3 and 10, platform 24 supports an underslung housing 26 
which carries an engine 28 under a well 26. The engine preferably 
comprises a 103 horsepower water-cooled internal combustion engine capable 
of propelling the vehicle up to about 20 miles per hour. A major portion 
of the engine is located below a plane drawn through the top points of the 
wheels. This is an important featue since it reduces the center of gravity 
of the vehicle. As a result, the vehicle is able to decelerate with a 
heavier load than would otherwise be possible. A one spot service 
compartment is located behind an access door 25 (FIG. 10). In the 
compartment are all of the daily maintenance check items like fuel, oil 
check and add, air cleaner, battery, hydraulic fluid level gauge, 
hydraulic tank, radiator fill and tool box. 
Referring to FIG. 2, body 14 also comprises a front traverse frame member 
34 and a corresponding rear traverse frame member (not shown). A depending 
counter weight 35 helps to balance the vehicle when the boom is extended. 
(FIGS. 1 and 12). 
Referring to FIGS. 1-3, a well 36 is defined by a horizontal flat plate 
member 38 and the upper portions of walls 30 and 32. The front part of the 
well is partially enclosed by a slanting front plate 40 and the rear of 
the well is partially enclosed by a left-hand rear member 46 and a 
right-hand rear member 48. Members 46 and 48 also cover the hoisting 
cylinders of hoisting assembly 244. As shown in FIG. 1, the well is 
arranged to receive the boom when the boom is lowered into the position 
shown in phantom lines so that a load may be maneuvered below grade. This 
is an important feature since it enables loads positioned below grade 
level to be maneuvered with a fork or drop block. 
Still referring to FIGS. 1-3, 10 and 12, axle and wheel assembly 60 
comprises a front axle 62 having a left end portion 64, a right end 
portion 66 and an axis of rotation 68. A front, left-hand wheel 70 is 
rotatably mounted to end portion 64 of axle 62. Wheel 70 has an outer 
periphery that defines a circle 72 having an upper point 74. A front, 
right-hand wheel 76 is rotatably mounted to end portion 66 of axle 62. The 
wheel has an outer periphery that defines a circle 78 having an upper 
point 80. Drum-type brakes 82 and 84 provide a means of braking wheels 70 
and 76, respectively. 
Assembly 60 also comprises a split rear axle 86 having a left end portion 
88, a right end portion 90, and an axis of rotation 92. A rear, left-hand 
wheel 93 is rotatably mounted to left end portion 88 of rear axle 86. The 
wheel has an outer periphery that defines a circle 94 having an upper 
point 95. Likewise, a rear, right-hand wheel 96 is rotatably mounted to 
right end portion 90 of rear axle 86. The wheel has an outer periphery 
that defines a circle 97 having an upper point 98. Drum type brakes 100 
and 102 provide a means of braking rear wheels 93 and 96, respectively. 
The axes of rotation 68 and 92 of the front and rear axles define a plane 
104 that is substantially horizontal to the ground level G. Upper points 
74, 80, 95 and 98 lie in a plane 105 that is substantially parallel to 
plane 104. The points of circles 94 and 97 closest to front axle 62 lie in 
a plane 103 that is perpendicular to planes 104 and 105. 
The wheels are driven by means of a front drive shaft 106, a rear drive 
shaft 107, and a transmission 108 that is coupled to engine 24. These 
components are arranged so that the vehicle has a 4-wheel drive 
capability. 
Referring to FIG. 2, suspension assembly 110 comprises a front yoke 112 
that is connected to front axle 62 and is rotatably mounted to frame 
member 34 by a pivot rod 114. Sway cylinders 116 and 118 are connected 
between yoke 112 and well member 38 so that load-carrying platform 16 
remains substantially horizontal when the vehicle is used on rough terrain 
or when one of the front wheels must be operated in a depression in the 
ground. The manner in which the sway cylinders operate is shown in FIG. 
2A. 
Referring to FIGS. 1-3 and 9, cab 124 comprises side frame members 126, 
127, 128, 129 and roof frame members 132, 133, 134 and 135 welded together 
as shown. A steering wheel 138 having an outer periphery that defines a 
circle 140 having an upper point 142 is located within the cab. Point 142 
lies in a plane 144 that is parallel to the planes 104 and 105. The 
steering wheel is connected by conventional hydraulic linkage to the rear 
wheels so that the load can be positioned with maximum maneuverability. 
Referring to FIGS. 1-3, pivot assembly 150 comprises a horizontal rod 152 
that is journaled through brackets 154 and 156. The brackets are rigidly 
attached to the frame of the vehicle body beneath member 38 in the manner 
shown. The longitudinal axis of rod 152 defines a pivot axis 158 which 
lies in a plane 159 that is parallel to planes 104, 105 and 144. 
Referring to FIGS. 1-3, boom assembly 164 comprises a boom 166 that has a 
fixed section 168, a telescoping movable section 176 and another 
telescoping movable section 184. The boom assembly is rotatably mounted on 
rod 152. The rod is positioned relative to steering wheel 138 in the cab 
such that plane 159 lies between the plane 105 and plane 144. This is an 
important feature since it enables the boom to place a load below grade 
level and it also enables the driver to have substantially unobstructed 
vision when a load is carried adjacent the ground level as shown in FIGS. 
10 and 13. Moreover, this placement of the rod maintains the center of 
gravity of the vehicle as low as possible commensurate with an ability to 
maneuver a load below grade level. 
Referring to FIGS. 4-7, fixed section 168 of the boom comprises walls 170, 
171, 172 and 173; movable section 176 of the boom comprises walls 178, 
179, 180 and 181; and movable section 184 of the boom comprises walls 186, 
187, 188 and 189. The boom also has an inner sleeve 192 comprising walls 
194, 195, 196 and 197. Section 184 terminates in a load carrying end 200 
which is connected to an end support member 202. The support member is not 
shown in FIG. 4 so that other portions of the apparatus may be more 
clearly seen. 
Referring to FIGS. 2 and 3, boom 166 is rotatable in an operating plane 204 
that is substantially perpendicular to planes 104, 105, 144 and 158. It 
should be noted that cab 124 is located completely on one side of plane 
204, whereas load-carrying platform 16 is located entirely on the opposite 
side of plane 204. This is an important feature since it enables well 36 
to be strategically placed below the boom to enable the maneuvering of a 
load below ground level as shown in FIG. 11. In addition, the foregoing 
arrangement of vehicle components enables the driver to have a 
substantially unobstructed view of the load irrespective of the manner in 
which the boom is moved in plane 204. 
Referring to FIGS. 4-7, boom extending assembly 206 comprises a hydraulic 
cylinder 208 having a rear end 210 that is attached to a rear wall 169 of 
boom 166. The cylinder is internally fitted with a reciprocating piston 
(not shown) that is attached to a connecting rod 212. The connecting rod 
terminates in a cylindrically-shaped head 214 that is connected to sleeve 
192 by rods 216,217 that pass through walls 195 and 197, respectively. The 
foregoing components enable the sleeve to be moved by the extension and 
retraction of rod 212 within cylinder 208. The movement of the piston 
within cylinder 208 is controlled by conventional hydraulic fluid and 
valves not shown. The rear end of sleeve 192 is connected to section 176 
of the boom by means of a rod 220 which passes through walls 181 and 197. 
A collar 222 spaces walls 181 and 197 with respect to each other. Sleeve 
192 is also connected to section 196 by means of a rod 224 that passes 
through walls 179 and 195. The rod is surrounded by a collar 226 that 
spaces walls 179 and 195 with respect to each other. 
A pulley 230 is rotatably attached to wall 181 of section 176 by a rod 232. 
A chain 234 is looped around pulley 230. One end of the chain is attached 
to rear wall 169 by a fixture 236 and the opposite end of the chain is 
attached to the rear end of section 184 by a fixture 238. A pulley 239 is 
rotatably attached to wall 179 of section 176 by a rod 240. A chain 241 is 
looped around pulley 239. One end of chain 241 is attached to the front 
end of section 168 by a fixture 242 and the opposite end of the chain is 
attached to wall 187 of section 184 by a fixture 243. 
The pulleys and chains cooperate in order to move section 184 inward and 
outward with respect to section 176. For example, if rod 212 extends 
sleeve 192 outward so that section 176 is also moved outward in the 
direction of arrow O, pulley 230 is also moved outward so that chain 234 
pulls fixture 238 and section 184 outward. Conversely, if rod 212 moves 
sleeve 192 and section 176 inward in the direction of arrow I, pulley 239 
is moved inward so that chain 241 pulls fixture 243 and section 184 
inward. This is an important feature since it enables both sections 176 
and 184 to be simultaneously moved inward and outward by a simple and 
fool-proof mechanism. 
Referring to FIGS. 1-3, hoisting assembly 244 comprises hydraulic hoisting 
cylinder-piston members 245 and 246. Member 245 comprises a cylinder 245a 
that is fitted with an internal piston (not shown) connected to a piston 
rod 245b. Likewise, member 246 comprises a cylinder 246a that is fitted 
with an internal piston (not shown) connected to a piston rod 246b. 
Cylinders 245a and 246a are connected to member 38 of well 36 by pins 247a 
and 247b in the manner shown in FIG. 2. Piston rods 245b and 246b are 
connected to a hoisting frame 248 by means of pins 249a and 249b, 
respectively. Hoisting frame 248 is welded to section 168 of the boom. The 
raising and lowering of the boom is controlled through cylinder-piston 
members 245 and 246 by conventional hydraulic control apparatus powered by 
engine 28. It should be noted that well 36 is made wide enough to 
accommodate a substantial portion of cylinder-piston members 245 and 246. 
By enabling these members to be located in the well, the center of gravity 
of the vehicle is lowered, thereby helping to stabilize the vehicle and 
increasing its effective load-carrying capacity. 
Referring to FIGS. 4-7, load-carrying assembly 250 comprises a drop block 
251 that supports a hook 252. The operation of the drop block is 
controlled by a pulley 254 having an axis of rotation 256; a pulley 258 
that is rotatably mounted on support member 202 by a rod 260; a pulley 262 
that is rotatably connected to wall 180 by a rod 264; a slanted pulley 266 
that is rotatably mounted to wall 172 by a rod 268; and a rotatable drum 
270 having an axis of rotation 272 that is mounted to wall 172 by a 
bracket 274. (FIG. 1). The rotation of drum 270 is hydraulically 
controlled and can be operated by a driver from the cab. A cable 275 is 
looped around the drum and pulleys and is attached to support member 202 
at a point 276. Rotation of drum 270 raises or lowers hook 252. If 
sections 176 and 184 of the boom are extended outward in the direction of 
arrow O, pulley 262 is moved outward so that the length of cable 175 
between pulleys 258 and 254 is increased. In this manner, hook 252 is 
maintained substantially at the same elevation above the ground while the 
boom is extended. The reverse process takes place as the boom is 
retracted. 
Referring to FIGS. 1 and 3, load carrying assembly 250 also comprises a 
fork assembly 280. Assembly 280 includes a pivot frame 282 that is 
rotatable around a horizontal pivot rod 284. Frame 282 supports an upper 
collar 286 on a bracket 287 and a lower collar 288 on a bracket 289. The 
center lines of the collars define a vertical pivot axis 290. Assembly 280 
also comprises a vertical frame 292 that supports upper brackets 293, 294 
which comate with collar 286, and lower brackets 295, 296 which comate 
with collar 288. The brackets and collars are rotatably mounted together 
by means of locking pins (not shown). Ford members 302 and 304 are 
connected by support bar 308 that is rotatably mounted on frame 292. (FIG. 
9). Frame 292 is rotated with respect to frame 282 by means of a hydraulic 
rotary actuator 310 that is remotely controlled by the driver from the 
cab. 
As shown in FIG. 3 in phantom line position R, fork members 302 and 304 may 
be pivoted 90.degree. with respect to their solid line position so that a 
load L can be simultaneously carried on the fork members and load-carrying 
platform 16. This unique feature is made possible, in part, by the 
arrangement of applicants' vehicle by which cab 124 and platform 16 are 
located on opposite sides of the boom. In addition, the fork can pivot in 
the direction of arrow P to position L shown in phantom in FIG. 3 in order 
to pick up skewed loads. Of course, a non-pivoting fork such as fork 292A 
(FIG. 10) could also be used if the advantages of pivoting are not 
desired. 
Referring to FIG. 8, load-carrying assembly 250 also comprises a fork 
attitude control system 320. System 320 includes a tank of hydraulic fluid 
322 and a tube 324 which connects the fluid to an operating valve 326. The 
operating valve is controlled by an operating handle 328. The hydraulic 
fluid is maintained under pressure by a pump 330 that is connected to 
valve 326 through a tube 332. Pressurized hydraulic fluid flows through 
tube 334 and through branch tubes 335 and 336. 
A master cylinder 340 is fitted with a piston 342 which divides the 
cylinder into an upper chamber 344 and a lower chamber 346. Piston 342 is 
connected to a piston rod 348 that is rotatably mounted to boom 166 
through a pin 350. Cylinder 340 is likewise rotatably mounted on the frame 
of the vehicle by a pin 352. Upper chamber 344 is connected to tube 336 
and lower chamber 346 is connected to a tube 354 that returns hydraulic 
fluid to valve 326 and also transmits the fluid to a branch tube 356. 
A slave cylinder 358 is fitted with a piston 360 that divides the cylinder 
into an upper chamber 362 and a lower chamber 364. The piston is connected 
to a piston rod 366 that is rotatably mounted to vertical frame 282 by a 
pin 368. Cylinder 358 is rotatably mounted to support member 202 by a pin 
370. 
The control system operates as follows: 
As boom 166 is being raised by cylinder-piston members 245 and 246, piston 
342 is raised so that hydraulic fluid flows through tube 336 to upper 
chamber 362 of slave cylinder 358. As a result, piston 360 moves toward 
pin 370 so that frame 282 moves in the direction of arrow D, thereby 
maintaining any load held on the fork members in a substantially 
horizontal plane. If the boom is lowered in the direction of arrow A, 
piston 342 in master cylinder 340 is moved downward so that the hydraulic 
fluid is transferred through tube 354 into lower chamber 364 of slave 
cylinder 358. Piston 360 then is moved toward pin 368 so that frame 282 is 
rotated in the direction of arrow C. As a result, any load carried on the 
fork members is maintained in a substantially horizontal plane as the boom 
is lowered. Valve 326 and operating handle 328 are arranged so that the 
above-described operation of the master and slave cylinders can be 
overridden and so that the frame 282 can be manually rotated in the 
direction of either arrow C or arrow D. 
A vehicle made in accordance with the invention is capable of performing a 
variety of material-handling operation. As shown in FIG. 9, a load can be 
lifted by drop block 251 while the fork is attached to the boom. This is 
an important feature because it permits either the drop block or the fork 
to be used without disassembling or assembling any components. FIG. 9 also 
illustrates configurations of well 36 and drum 270 that are somewhat 
different from the like components shown in the other figures. FIGS. 10 
and 13 illustrate the unobstructed vision enjoyed by the driver as a load 
is being carried near ground level. This is an important feature when the 
vehicle is used in a warehouse or stock-piling yard. FIG. 11 illustrates 
the cooperation of boom 166, pivot assembly 150, and well 36 so that a 
load can be maneuvered below grade level G. FIG. 12 illustrates the height 
to which the boom is extendible for placing a load on top of a building. 
Those skilled in the art will recognize that the preferred embodiment 
described herein is merely exemplary of the preferred practice of the 
invention which can be altered and modified without departing from the 
true spirit and scope of the invention as defined in the claims.