Note: Descriptions are shown in the official language in which they were submitted.
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1 FIELD OF INYENTION
This invention relates to articulated booms and finds one particular
application in truck mounted articulated booms secured at one end to the truck
body and at the other to a work platForm or bucket carrier.
BACKGROUND OF THE IrlVENTION
Articulated booms are well known in the art. See for example, United
States Letters Patent 2,881,030, 2,940,539; 3,082,842 and 3,834,488. In
operation, the upper arm is pivoted relative to the lower, which is itself
pivotable, both to the des;red positions. To maximize use capabilities, it is
pre~erable that the boom have the capabilities of moving the arms through a
vertically aligned co-linear position (centered position) to a vertically
over-centered position. In an attempt to achieve maximum articulation, the
prior art constructions provided individual hydraulic cylinders acting on the
arms, pivoting on pins joining the arms, or employed cables or chains
connected to the arms for relative movement of the arm. However, no
articulated boom employing hydraulic cylinders and pin connection has provided
relative rotation of the upper arm relative to the lower arm to exceed about
210.
In an attempt to achieve a greater angular separation of the upper
and lower arms the prior art artlculated booms have employed chains or cables
to rotate the upper arm relative to the lower arm By employing chains or
cables, angular separation of the two arms of about 270 has been achieved.
However, the strength o~ the cables or chains employed used to rotate and
secure the arms is only as great as the weakest link of the chain or weakest
part of the cable. Since these articulated booms are employed to lift workers
on work platforms, for example, to repair hydro or telephone lines, safety is
paramount to requiring 100% reliability and consequently, this approach has not
been widely accepted in the industry.
Additionally, the use of cables and chains requires cumbersome
support;ng assemblies and widely restr;cts maneuverab;lity of the articulated
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1 boom.
It is therefore an object of this ;nvention to provide an
articulated boom and assembly useful therewith which overcomes the
aforementioned difficulties with the pr~or art, permitting safe relative
angular rotation between the lower and upper arms of about 270.
Further and other objects of the invention will be realized by
those skilled in the art from the summary of the invention and detailed
description of preferred embodiments thereof.
SUMMARY OF THE INVENTION
According to one aspect of the invention, an articulated boom
and assembly is provided, comprising:
(a) a lower boom arm;
(b) an upper boom arm foldable over the lower arm, pivotal with
respect to the lower boom arm;
(c) Hydraulic cylinders positioned between the boom arms and
having piston rods extending therefrom, the hydraulic cylinders with the
piston rods pivotally secured at one end to each boom arm intermediate
the boom arm's ends, one hydraulic cylinder being pivotally secured to
the underside of the upper arm and the other cylinder p~votally secured
to the upperside of the lower arm facing the upperside when the upper
arm is folded over the lower arm; -and-
(d) a linkage for pivotally connecting the upper arm, lower arm
and hydraulic cylinders, the linkage comprising three points of connection,
the points when linearly connected forming a triangle (preferably an
isoceles triangle) and the points of connection are the apexes of the
triangle with:
(i) one apex of the triangle (for example, in the case of the
points of connection forming an isoceles triangle, the apex created by
the meeting of the two equal sides)~ directed towards the hydraulic
cylinders and piston rods between the upper and lower boom arms, and the
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1 linkage being pivotally connected at this point of connection to the
free ends of the cylinders or piston rods not connected to the arms;
(ii) another apex of the triangle proximate the upper arm being
pivotally secured to the end of the upper arm at this point of connection;
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tiii) another apex of the triangle proximate the lower arm being
pivotally secured to the end of the 10wer arm at this point of connection,
the distances between the apexes referred to in subparagraphs ~ii) and
~iii) being less than the vertical distance from the apex referred to in
subparagraph ~i) to the line joining the apexes referred to in sub-
paragraphs (ii) and (iii), thus permitting the arms to be rotated ap-
proximately 270 from one another.
According to another aspect of the invention, both the upper
and lower arms may be about the same length.
According to another aspect of the invention, the linkage may
be generally T-shaped in cross-section having a top and spine extending
from intermediate the ends of the top, with the point oF connection
forming an apex of the triangle (preferably an isoceles triangle) directed
towards the hydrau'lic cylinders between the upper and lower boom arms
being disposed on the spine extendlng from the top, and the top is
oriented with the other points of connection forming the other apexes of
the triangle situate proximate'the ends of the top.
According to another aspect of the invention, a third arrn may
be p;votally secured to the en~ of the upper arm remote the arm end
2~ secured to the linkage to pivot at least about 90 relative to the upper
arm.
The lower arm of the articulated boom may be lifted by a
hydraulic cylinder to a vertical position as necessary. There~ore, the
articulated boom and assembly may be truck; mounted and used for examp'le~
for elevating workmen to repair telephone wires or transmission lines,
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1 but also, with the addition of the third arm, the articulated boom and
assembly may be mounted on a vehicle and be used to permit workmen to
inspect the underside of, for example, a bridge.
In operation, the two hydraulic cylinders between the upper
and lower boom arms are connected to a common reservoir and activated by
a common control system. Because the lower arm carries the weight of the
upper arm (when initially folded thereon), the upper cylinder is the
more effective when both cylinders are activated causing the upper arm
to pivot on the linkage relative to the lower arm until the upper arm of
the articulated boom rotates over 90 relative to the lower arm. At that
moment, the load supported and carried by the lower arm is considerably
reduced, permitting the hydraulic cylinder secured to the lower arm to
operate more effectively. As the cylinder controlling movement of the
upper arm reaches the end of its stroke, generally at about 135, an
equalization and transfer of power occurs to the hydraulic cylinder
controlling the movement of the lower arm, thus causing the llnkage to
start to rotate permitting the upper arm to be positianed at angles of
up to about 270 relative to the lower arm. At the extreme, and in
instances where the lower arm has not been pivoted to an elevated position,
the upper arm extends generally down and below the truck or vehicle
mounting it and if a third arm is pivotally secured to the upper arm at
the free end, and supports a work platform, the assembly becomes very
useful for bridge inspection by positioning the third arm under the
bridge~
The invention will now be illustrated with reference to the
drawings, illustrating preferred embodiments of the invention and to the
detailed description of the drawings.
BRIEF DESCRIPTION OF THE ~RAWINGS
Figure 1 is a close-up view of part of the articulated boom
and assembly of Fiyures 1 and 2 partially disassembled.
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1 Figure 2 is a close-up perspective view of the articulated
boom and assembly partially unfolded shown in Figure 1.
Figure 3 is a close-up view of part of the articulated boom
and assembly of Figures 1 and 2 partially disassembled.
Figure 4 illustrates various positions of the articulated boom
and assembly during one mode of operation.
Figures 5A to 5D inclusive, illustrate individually the respective
positions of the articulating boom and assembly shown in Figure 4.
Figure 5E is a schematic drawing illustrating the relationship
between various points of the linkage used in the articulating boom and
assembly shown in Figures 1 to 4 inclusive.
Figure 6 is a rear ~iew of a truck mounting an articulated
boom and assembly according to a second preferred embodiment oF the
invention.
Figure 7 is a schematic of one mode of operation of the articulated
boom and assembly shown in Figure 6.
DETAILED DESCRIPTION OF THE DRAWINGS
With reference to Figure 1, there is shown truck 10 mounting
articulated boom and assembly 12 supported on pedestal 14 to carry work
bucket 16 for carrying a person to work to sites remote the truck.
Truck 10 carries equipment housing 16 on trailer 17 for housing the
control equipment and hydraulic equipment (including reservoir, pumps,
controls and circuitry leading to and from the hydraulic cylinders
employed, 18, 20 and 22).
Pedestal 14 carries frame 24 comprising two spaced plates 26
and 28 spaced by cylindrical pins 30 and 31. Frame 24 ;s secured at 32
and 34 to rotatable platform 36 secured to rotate over stationary pedestal
Articulated boom and assembly 12 and incidental components
comprise:
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1 (a) lower boom arm 38 pivotably sec~red at end 40 on p;n 30 to
frame 24 to be raised and lowered by hydraulic cylinder 42 having piston
rod 44 reciprocal therein, cylinder 42 being secured on pin 31 for
relative rotation with respect thereto and piston rod on axel 46 secured
to frame 48 on the underside of arm 38, for relat;ve rotation with
respect thereto,
- (b) upper boom arm 50 secured to, and folded over, lower arm 38
and pivotal with respect thereto;
(c) hydraulic cylinders 18 and 20 positioned between the boom
arms, having piston rods 52 and 54 extending therefrom respectively,
hydraulic cylinder 18 pivotally secured at one end by pin 55 to plate 56
on the underside of upper arm 50 and cylinder 20 pivotally secured at
one end by pin S7 to plate 58 on the top of lower arm 38;
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(d) T-shaped linkage 60 comprising four spaced plates 69, each
plate 69 having a top portion 70 and depending spines 72 extending from
top portion 70 intermediate their side edges ioined together (not
shown) to provide three channels 74.
Aligned bores 76, 78 and 80 are provided through T-shaped
2~ linkage 60 proximate the extremities (side edges of portions 70 and end
of spines 72) of T-shaped linkage 60 for pivotally securing hydraulic
cyl;nders 18 and 20, (piston rods 52 and 54 are each pivotally secured
to T-shaped linkage 60 at 62 and 64 respectively by pin 92 passing
through bore 80 and plates 88 and 90 on the ends of piston rods 52 and
54) and upper and lower arms 50 and 38 respectively to linkago 60 at 66
and 68 respectively by pins, as for example, by a pin passing through
bores 76 and 78 and bores 81 aligned with bores 76 and 78 through series
of spaced connecting plates 84 and 86 of connectors 85 and 87 extending
from the ends of arms 38 and 50 respectively, for meshing with spaced T-
shaped plates 69 of T-shaped linkage 60. Therefore, plates 88 and 90 of
1 piston rods 52 and 54 are secured in the spaces 74 between spines 78 of
linkage 60 by pin 92 passing through bores 80 and the holes through
plates 88 and 90 and plates 84 and 86 are meshed with plates 64 and
secured in the spaces 74 between plate portions 70 of linkage 60 by pins
(not shown) passing through bores 76 and 78 and aligned bores in plates
84 and 86.
With reference to Figure 4, the rotation only of the upper arm
50 relative to the stationary lower arm 38 of the articulated boom is
illustrated without regard to the elevation of lower arm 38 by hydraulic
cylinder 42.
As the hydraulic cylinders 18 and 20 are connected to a common
reservoir and activated by a common structural system, when hydraulic
fluid is fed to cylinder 18, fluid is also fed to cylinder 20. However,
because lower arm 38 initially carries the additional weight of the
upper arm 50, cylinder 20 is the only cylinder initially effectively
activated. Therefore, initially rod 54 of cylinder 20 is pushed against
linkage 60, elevating and rotating upper arm 50 relative to linkage 60
and arm 38 (See A of Figures 4 and 5) until upper arm 50 rotates over-
center. (See B of Figures 4 and 5). At that moment, the load supported
and carried by lower arm 38 is considerably reduced, permitting hydraulic
cylinder 18 to operate more effectively and begin to rotate linkage 60
- after cylinder 20 has completed its stroke (when upper arm 50 forms an
angle of about 135 to lower arm 38). At that point, an equalization and
transfer of power occurs allowing cylinder 18 to rotate linkage 60 by
extension of piston rod 54 to pivot upper arm 50 safely through position
C to position D of Figures 4 and 5. To fold the assembly, the cylinders
are operated to reverse the sequence of the steps. With reference to
: Figure 5E, the relationship between the distance (l) between point 66
and point 68 on the linkage 60 (shown as a T) and the vertical distance
3~ (L) From point 62 to the line joining point 66 and point 68 (l) is shown
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1 Length "L" is longer than length "l" between points 66 and 68.
For elevating arm 38 relative to truck 10, cylinder 42 is
activated causing rod 44 to push arm 38 away from cylinder 42.
~Jith reference to Figures 6 and 7, there is shown an articulated
boom and assembly 100 mounted for use for bridge inspection. Articulated
boom and assembly 100 are substantially of the same construction as
- articulated boom and assembly 12 previously described except for the
interposition of:
(a) pivotal arm 102, pivotal on pin 107 on end 104 of arm 50
between arm 50 and work bucket 16;
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(b) hydraulic cylinder 106 secured intermediate the other end of
arm S0, on the side of arm 50, remote cylinder 20. Reciprocal piston
rod 108 extends from one end of hydraulic cylinder 106 and is pivotally
secured to arm 102~ The other end of hydraulic cylinder 106 is pivotally
secured on pin 110 secured between spaced plates one of which being
shown at 112. As can be seen, in Figure 6, articulated boom and assembly
12 and addlt1Onal hydraulically controlled pivotable arm 102 has been
fully extended (by controls-not shown) for inspection of the underside
114 of bridge 116.
Truck 10 has been stabilized by outrigger stabilizers 120
extending from the sides of truck lO to permit rota~ion of the assembly
on rotatable platform 36 to position boom and assembly 100 transverse
the longitudinal axis of the truck to be unfolded in the inspection
position. For the purposes of unfolding the entire assembly, arms 38,
50 and 102 are unfolded to position G shown in Figure 7. The unfolded
structure is then moved through positions H, I, and J to inspection
position K under bridge 116.
As many changes can be made to the embodiments hereinbefore
3~ described without departing from the scope of the invention, it is
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1 intended that all matter contained herein be interpreted as illustrative
of the invention and not in a limiting sense.
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