Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to hoists or cranes of
the type mounted on a truck body , for loading or unloading the
truck, and in particular to an improved rota-tion means for
rotating the vertical support column which supports the boom
of the crane or hoist.
BACKGROUND OF THE INVENTION
A typical truck mounted crane or hoist, of the general
class to which the invention relates, is shown in U.S. letters
Patent number 3,0a2,889. Typically, such hoist will have a boom
which may be of a fixed length or may be telescopic mounted on
top of a vertical post or column. The bottom end of the post or
column wi~ be mounted on or below the truck bed. Typically, some
form of rotation mechanism is provided for rotating the column to
swing the boom into the desired position. In the past, such
ro~ation mechanism has usually incorporated some Eorm of sprocket
attached to the bottom end of the vertical column, and operated
by means of a chain drive. rrhe chain may be moved to and fro by
means such as for example two hydraulic cylinders one at each end -
of the chain. Such a system is reasonably effective. However it
suffers from serious disadvantages.
It is desireable that hoists of this type may be made
according to a standard design and then attached to various different
makes of truck body, depending upon the customers requirements and
choiee .
'rhe use oE a chain and two hydrau:lic cylinders, means
that the two hydraulic cylinders must be attached on to the truck
frame, or to the underside of the truck bed. Some form of attachment
means must be provided which must be located precisely in relation
to the position of the sprocket. Since there are wide variations in
the design of truck bodies, it i9 thus necessary to have a variety
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of different attachment means, In addition, this factor also leads '~;to problems in servicing, since the truck body may flex or move
consequently changing the relationship between the chain and the
sprocket. From all of these viewpoints it is therefore desireable
that the entire hoist and rota-tion mechanism shall be built as far
as possible as a single unit, which may then be attached to any ~
suitable position on the truck body, without the requirement of -
different mounting means for different truck bodies.
In addition to these factors, it has also been found
necessary to provide stabilizing legs which are extendable on
opposite sides of the truck body so as to prevent the truck body
from being tipped over by heavy loads carried on the boom. TypicaIly
stabilizing legs in the past have been attached to the truck bed
as a separate attachment. They are usually swingable in a vertical
plane, and operated by hydraulic cylinders so that they may be
swung upwardly out of the way or downwardly into contact with the
ground. Again, the separate attachMent of the stabilizing legs
requires special engineering for a variety of different types of
truck beds. It is therefore desireable that the stabilizing legs
shall be incorporated in the design of the hoist itself so that
the entire unit consisting of the hoist boom vertical column and
stabilizing legs may be attached to the truck bed as a single
integral unit. In addition, in this way it is possible for the
stabilizing legs to actually stabilize the support of the vertical
column of the hoist itself. In this way, there are no twisting
stresses~applied through the truck frame or truck bed between the
location of the hoi~t on the one hand, and the location of the
stabilizing legs on the other.
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BRIEF SUMMARY OF THE INVENTION
The invention therefore seeks to overcome the foregoing
disadvantages by the provision of hoist apparatus of the type
adapted to be mounted on a truck adjacent the truck bed, leaving
the truck bed clear, for use in unloading or loading the truck or
the like, and comprising a boom, hoist means on said boom, a
vertical support column, said boom being mounted on the upper end
of said column, and said support column being rotatably mounted
for rotating said boom, drive gear means located adjacent the lower
end of said support column, rack means meshing with said drive
gear means, guide means for guiding movement of said rack to and
ro relative to said drive gear, housing means supporting said
vertical column, and at least partially embracing said drive gear
and supporting said guide means, and, power operated means connected
with said rack, and mounted on said housing, for driving said
rack to and fro.
It is a urther and related objective of the invention
to provide a hoist apparatus having the foregoing advantages and
in which the housing incorporates universal mounting means for
attachment to the rear end of a truck body, and being inherently
adapted to suit a wide variety of different truck bodies without
modification.
It ~ afurther and related objective of the invention
to provide hoi~t apparatus having the ~oregoing advantages in which
the power operated means comprises two power cylinders preferably
hydraulic cylinders attached to the housing , and coupled to
opposite ends o~ the raclc means.
It is a ~urther and related objective of the invention
to provide hoist apparatus having the foregoing advantages in-
corporating stabilizing leg means attached to the hoist apparatus
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and providing direct support for the vertical support column, and
operable between raised inactive positions, and extended supporting
positions by any suitable power operated means.
The various features of novelty which characterize
the invention are pointed out with particularity in the claims
annexed to and forming a part of thi~ disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its use, reference should be had to
the accompanying drawings and descriptive matter in which there
is illustrated and described a preferred embodiment of the invention.
IN THE DRAWINGS
Figure 1 is a perspective illustration showing a truck
with a hoist mounted thereon;
Figure 2 is an enlarged perspective illustration
partially cut away, showing the ~otational apparatus and vertical
support column of the hoist according to the invention;
Figure 3 i9 cut away perspective of part of Figure 2.
Figure 4 is a section along the line 4-4 of figure 3;
Figure 5 is a section along the line S-S of figure 4,and
Figure 6 isa schematic drawing of the hydraulics.
Referring initially to igure 1, it will be seen that ~ `
the truck ~hown as T has a truak bed B for carrying a load. Typically
the truck bed will be flat, and will be suitable for carrying a
wide variety of loads typically briaks, blocks or other heavy
aonstruation component~, and typically being loaded on pallets
or the like.
Loading and unloading of these heavy items from the truck
bed requires power operated hoist means , and for ease of handling
trucks of this type are fre~uently provided with a hoist such as
the hoist shown in figure 1. The hoist will be seen to comprise
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a boom 10 mounted on a vertical support column 12. The boom 10
will usually incorporate some form of hoist apparatus having a
hoist cabel 14, and provided with power operated means for shorten-
ing and lengthening the cable. Such means may be in the form of
a drum (not shown) or may be in the form of an hydraulic cylinder
16 or any other suitable means which may be provided.
The boom 10 may be formed of telescopic sections lOa, -
lOb etc. , so that it may be used for off loading at for example ~ -
a building site where the load is required to be deposited at some
distance from the truck. The telescopic sections lOa~ lOb etc.,
will be provided with any suitable power operated means for
extending and retracting the sections. The extended position
is not shown but a portion of the extension mechanism, comprising
a hydraulic cylinder(not shown) and operating shaft indicated as
18 are shown in figure 1. The hoisting cable may simply have a
free end provided with a hood, or may alternatively be doubled
over a pulley 20 which is it~elf provided with a hook, or for
example a three sided hoisting bracket 22 having tines 24 for
extending under a typical pallet.
~20 The vertical support column 12 according to this prefer-
red embodiment of the invention is mounted at its lower end
in a housing 26, and is rotatable about its vertiaal axis so as
to swing the boom 10 to and fro on either side of the truck.
Provision may also be made for swinging the boom 10
upwardly and downwardly~ Typically, i such provision is required
it will be by means of for example hydraulic cylinder 28 mounted
between the boom 10 and the vertical support column 12, at some
point just above the housing 26.
The vertical support column 12 extends completely
through the housing 26. Eiousing 26 will preferably be provided
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with any suitable bushings or the like within th~ interior thereof
(not shown) for example at the locations of the enlarged collars
30 at the upper and lower ends of the housing 26. In this way the
support column 12 may be rotated within the housing 26, which
itself remains permanently fixed to the truck, in order to support
the housing 26. In a vertical orientation as shown , a pair of
A frame support bars 32 are provided, being welded at their upper
- ends to the housing 26 as shown, and extending downwardly and
outwardly in the form of a letter A. At their lower ends they
are welded to a horizontal base plate 34. Attachment lug members
36 are attached to the four corners of the plate 34 extending
orwardly and backwardly. They are attached to any suitable portions
of the truck such as the frame F by means of the U-bolts 38.
In order to stabilize the hoist , and the truck~ when
the boom is swung outwardly to one side or the other with a
heavy load thereon, stabilizing legs 40 are provided, h~ving
yround engaging feet 42 at the free ends thereof. The inner ends
of the legs 40 are pivotally mounted between a pair of attachment
brackets 44. The inner ends of the brackets 44 are welded to
downwardly extending portions of base plate 34, overlying the
sides of the frame member F of the truck thus stabilizing both the
position of the hoist itself and also the truck. Additional
bracing stru~s 46 may be welded between the free ends of the
bracket 44 and the base plate 34 as shown in ~igure 1.
The legs 40 are swung upwardly and downwardly by any
suitable power operated means, in this case the hydraulic
cylinders 48. The hydnaulic cylinders 48 extend between the
upper end of the housing 26, where they are swingably moun~ed,
to a point approximately mid way along the legs 40.
It will of course be appreciated that all of the power
operated means referred to herein, which in the case of this
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embodiment consist of hydraulic cylinders such as 16, 18, 28,
and 48 will all be provided wi-th suitable hydraulic pressure hose
connections (not shown) and control valves (not shown) by means
of which hydraulic pressure from a suitable pump or source (not :~
shown) carried on the truck may be applied to the various
cylinders for the various purposes concerned. All of these features
are very well known in the art and require no description and are
consequently shown only schematically in figure 6.
In order to rotate the column 12, so as to swing the
boom 10 to one side or the other of the truck, there is provided
a drive gear 50 at the lowex end of the column 12. The gear 50
consists essentially of a toothed ring extending around the column
12 as shown in figure 3, and 4. In order to drive the gear 50,
there is provided a rack member 52. The rack member 52 is slideably
carried within. a double ended cylinder 54. At each end of the rack
52 there is provided a suitab~ piston 56 fit-ting snugly within
the cylinder 54.~t the centre o the cylinder 54 a portion of the
side wall is cut out to provide a window 58 thereby permitting
the drive gear 50 to enter the cylinder 54 and be engaged by the
rack 52 as shown in figure 4 and 5. A pressure pad 60 is provided
within the cylinder 54 to apply pressure to the smooth side of
the rack 52 so as to hold the toothed side in engagement with
the gear 50. The pad 60 may be of two part construction, the
facing being made o any ~uitable bushing materlal ~uch as bronze,
or some other self lubricating material for example so as to
provide an extended life, and at the same time to permit replace-
ment of the wearing surface.during servicing.PreferabLy , there
will be provided a pair of.adjustment bolts 62 whereby the pad
60 may be adjusted to the correc~ position, and take up any wear
which may arise between servicing. The cylinder 54 is partially
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protected within a protective shield member 64 and the shield
64 is preferably provided with a window 66 to give access to the
adjustment bolts 62. The shield member is semi-cylindrical and
will be held in position by releaseable means such as the straps
68 (see figure 2).
Any suitable power source may be used to drive the rack .
52 to and fro so as to rotate the drive gear 50. In the case of
this embodiment of the invention however use is ~lso made of .;
hydraulic pressure. For this purpose, each end of the cylinder
54 is employed as a hydraulic pressure cylinder. It is thus
provided with hydraulic pressure pipes or hoses 70 one at each
end, each end of the cylinder 54 being otherwise closed and
sealed. The pistons 56 at each end of the racks 52 are adapted
to seal against the hydraulic fluid. The hoses or pipes 70 will
communicate through any suitable control valve system (not shown)
with a source of hyraulic fluid pressure. ~y the operation of
a ~uitable valve syste~-~( see figure 6) hydraulic fluid may be
admitted under pre~sure through the hose or coupling 70 at one
end of the cylinder 54, while the hydraulic fluid is released
through the hose or coupling 70 at the other end of the cylinder
54. In this way, the rack 52 , and the two pistons 56, operating :
within the common cylinder 54 consitute essentially a double
aating hydraulic power~y~tem, with the rack 52 itself constituting
the operating rod o the aonventional cylinder.
As best shown in figure 4, the cylinder 54 i8 made up
of two substantial identical cylinder end portions 54a and 54b, and
a central mounting portion 54c. The central portion 54c is ..
e~entially an open ended cylinder, being provided at each end
with a female threaded counter bore 72, for receiving the threaded ~.
ends 74 of the end cylinder portions 54a and 54b.
In this way, servicing of the cylinder 54 is greatly
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simplified.
The central portion 54c is provided with a pair of
mounting flanges 76 which may be bolted directly to the frame
members 32.
In this way, servicing of the en-tire sub-assembly
constituting the cylinder 54 and the rack can be achieved simply
by removing the bolts attaching the flanges 76 to the frame 32.
As shown schematically in figure 6, the entire system
is hydraulically powered and controlled. A pump 78 is supplied
from a reservoir or tank 80. The hydraulic medium, fxom the
pump 78 is passed through a flow divider 82. A portion of the
flow supplies the cylinder 54, through the electri~ally operated
valve 84.
A further portion of the flow operates the stabilizer
cylinders 48, through the control valve 86 .
A rota~able coupling 88 supplies hydraulic medium to
the control valves 90 which then control the cylinders 16, 18 and
28.
The operation of the apparatus is self evident. A load
may be attached to the fork or lifting device on the boom, and
the boom may be raised upwardly, and the cable may be extended or
hoisted, and the boom may be extended or retracted, simply by
the operation of the valves above noted. When it is desired to
swing -the boom to one side or the other of the truck, then by the
operation of the valve 84, hydraulic pressure medium is applied
to either one end or the other of cylinder 54 thereby causing
the rack to move and rotating the toothed ring gear 50. This in
turn rotates the column 12 to which the boom is attached.
Depending upon the nature of the loads to be carried on
the boom, the stabilizing legs will of course first of all
have been extended outwardly if required.
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~aving described what is believed to be the best mode
by which the invention may be performed, it will be seen that
the invention may be particularly defined as follows: -~
Hoist apparatus of the type adapted to be mounted ~
on a truck adjacent the truck bed, leaving the truck bed - : .
clear, for use in unloading or loading the truçk or the
like and comprising, boom means, hoist means on said boom
means, a vertical support column, said boom means being :
swingably mounted on the upper end of said column~ and said
support column being rotatably mounted for rotating said
boom means and said column in unison, drive gear means located
ad~acent the lower end of said support column for rotating
the same, rack means meshing with said drive gear means,
and moveable to and fro along a linear path relative to
said drive gear means~ a non-rotatable vertically oriented
housing means supporting and enclosing a portion of said
vertical column and said gear means adapted for mounting in
fixed position on a portion of said truck and supporting
said ~ertical column along a substantial portion of its ~. .
length, power operated means connected with said rack, and
mounted on said housing means, ~or driving said raclc to and fro ..
thereby rotating said support column~ and sald boom means
in unison on ei~her side o said truck bed~ supporting rame ~.
members forming part o said housing means for supporting said `:
vertical column; attachment brackets extending from a lower portion
oE said housing means at an angle downwardly on opposite sldes
thereof; ground engaging strut means swingably attached to the lower :~.
outer ends of said attachment brackets, and, power cylinder means
extending between the upper end of said housing means and
respective said strut means, operation o~ said power cylinder
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means swinying said strut means between upwardly angled dis-
engaged positions and downwardly angled ground engaging
positions, said power cylinder means thereby directly supporting
and stabilizing the upper end of said vertical housing means and
said column enclosed therein against heavy loads applied at the
end of said boom means, when said boom means are swung outwardly
on one or other side of said truck
; The invention further comprises hoist apparatus
having the foregolng features and wherein said rack means
comprises an elongated linear rack member having tooth means
on one side, adapted to engage said drive gear means, the other
said side being smooth, said rack mem~er being located within
said power cylinder means and moving along a predetermined
linear reciprocal path to and from there-within, and including a
pressure pad located within said cylinder means and engaging
said smooth side of said rack member for holding the same with
said tooth means in engagement with said drive gear means, and
adjustment means for adjustment of the pressure applied by said
pressure pad on said rack member.
The invention further comprises hoist apparatus having
the foregoing features and including protective shield means
partially enclosing ~aid cylinder means.
The invention ~urther comprises hoist apparatu~
having the oregoing features and including attachment lug means
on said housing means and extending forwardly and rearwardly
therefrom, whereby the same may be secured both in front of
and behind said housing means lengthwise along the frame of a
truck adjacent the truck bed thereby leaving the truck bed
clear for loading and unloading as aforesaid.
The foregoing is a description of a preferred
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embodiment of the invention which is given here by way of
example only. The invention is not to be taken as limited
to any of the specific features as described, but comprehends -~
all such variations thereof as come within the scope of the
appended claims.
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