Note: Descriptions are shown in the official language in which they were submitted.
1090323
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: ` FIELD OF THE INVENTION
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This invention relates to cranes of the type used in
heavy construction operations, and more particularly to a winch
mechanism used in cranes to draw in and let out the load line
or topping line.
.: THE PRIOR ART
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Crane structures are used extensively throughout the
construction industry for hoisting and moving materials and
equipment used in the building process. Generally, the cranes
' 10 are composed of a base structure rotatably mounted on either a
stationary foundation or a mobile power unit. A boom is pivo-
tally attached to the base structure, and a load hoisting cable,
generally controlled from an operating station near or on the
base structure,depends from the end of the boom for attaching
'~ loads thereto. A gantry structure is fixedly attached to the
base, behind the boom pivot, and a topping line runs from the
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top of the gantry to the point of the boom. The boom is
elevated and lowered by means of the topping line which leng-
~`jl thens and shortens.
Prior art cranes have generally used a rotational
drum as the winch mechanism for drawing in and letting out the
topping line and load line. In these cranes, the drum is
merely rotated to wind in or let out cable, and the cable is
wound onto and fed from the drum as desired. In this arrange-
ment, cable is wrapped over itself as it is drawn in and wGund
i~ onto the drum. Thus, the cable
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experiences substantial wear as a result. Further, these
systems re~uire cable guides to prevent crosswinding of
the cable onto the drum. Moreover, the torque required to
turn the drum varies as the cable is wound onto the drum
because the effective drum diameter continuously changes
as cable is added to the drum.
SUMMARY OF THE INVENTION
In accordance with an aspect of the invention there is
provided in a crane having a boom with a first end adapted
for securing a load thereto and a second end pivotally
attached to a base for supporting the boom therefrom, a
winch mechanism comprising: a first drum having multiple
grooves therein, a second drum having multiple grooves
therein, a first frame for rotatably supporting said first
drum for rotation about the axis thereof, a second frame
for rotatably supporting said second drum for rotation
about the axis thereof, means for pivotally attaching the
first frame to the second frame for canting the first drum
; relative to the second drum with the axes of rotation of
the first and second drums being maintained in parallel
planes, adjustment structure attached between the first ~-
; and second frames for adjusting the cant of the first drum
relative to the second drum, a cable alternately wrapped
between the grooves of said first and second drums, one
end of said cable extending along the boom to the first
end of said boom, and means for driving at least one of
said drums to draw in or let out said cable.
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The present invention discloses an improved load lifting,
crane structure which overcomes many of the deficiencies of prior i
¦art apparatus by utilizing a mast and upper tension member system ¦
affixed to the top surface of the boom. This system permits the
¦ use of hydraulic cylinder means for elevating the boom while
i I subjecting the boom only to compressive loads and not to bending
¦ moments. This system also permits the adaptation of a
l counterweight to a crane in a novel manner whereby the
counterweight is supported by a tension member which joins into
¦the upper tension member system to achieve a uniquely effective
~; jload path.
In accordance with one embodiment of the invention, the
i crane structure comprises a base having a boom pivotally supported
¦ at one end from the base. The opposite end of the boom is adapted
¦ for receiving the load to be lifted by the unit. Hydraulic
. ¦ cylinder(s) are connected to the base and to an intermediate
location on the boom such that when the cylinder(s) are retracted -
the boom is substantially horizontal and when the cylinders are
extended the boom pivots to a position approaching the vertical.
A mast is attached to the boom at a location on the upper surface
of the boom and provides for a rearwardly disposed tension member
or back-stay running from the top of the mast to the rear portion
1f the boom, and a forwardly disposed tension member or pendant
~line running from the top of the mast to the point of the boom.
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` I In accordance with another embodiment of the invention
; Ithe back-stay member can be made as an extendable spring and
Idampener that will serve to cushion dynamic overloads such as are
¦incited by wave action in marine applications.
1 5 ¦ In accordance with yet another embodiment of the
¦invention the mast is given a lateral dimension exceeding the
- ¦width of the boom cross-section and the forwardly disposed upper
¦tension members include at least two diagonal components running
¦from one side of the upper end of the mast to the opposite side
¦of the boom. The diagonal components are preferably clamped -
Itogether at the point where they cross. This arrangement serves
¦ to support the end of the boom during operation in out of level
I l conditions in such a manner that the boom is not subjected to
¦ twisting and side bending moments.
¦ ~ In accordance with yet another embodiment of the
invention a counterweight is hingedly attached to the end of the
I boom supported from the base. When the counterweight is aligned
I ¦ with the boom, it may be selectively moved from an extended to a
¦ retracted position along a path substantially parallel to the
¦ longitudinal axis of the boom. In this embodiment of the
invention, the fact that the counterweight is not fi~edly attached
to the boom but is hinged therefrom permits the counterweight to
¦ be angularly rotated relative to the boom during hoisting
¦ operations. In this way, the counterweight may be extended to
¦ work at a significantly greater radius than would be possible with
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10903Z3
a fixed boom-counterweight structure. Because the counterweight
may be retracted relative to the boom, clearance problems caused
by structures adjacent the work area of the crane are likewise
overcome.
In this embodiment, the crane of the present invention
is adapted with structure for maintaining the hingeable
¦counterweight structure substantially horizontal as the boom is
~,t I pivoted on the base. In this arrangement, the counterweight is
hinged relative to the boom and is maintained horizontal
¦ regardless of the vertical angle of the boom while hoisting or
¦ performing similar operations. The hingeable counterweight
structure, when maintained horizontal throughout the angular
elevation range of the boom, eliminates ground clearance problems
that would otherwise obtain in that the counterweight stays in
¦ substantially the same position relative to the ground and other
surrounding structure as the boom elevates.
~! ' In accordance with another embodiment of the present
invention, the counterweight comprises a longitudinal arm
hingedly attached from the boom in the vertical plane of the boom.
Attached to the end of the longitudinal arm remote from the boom
is a weight unit wherein the weight of the counterweight unit is
concentrated. This counterweight structure is chosen in order to
provide the bulk of the weight of the counterweight with a maximum
moment arm through which to act thereby increasing the
leffectivl ess of the counterweight. In accordance with this
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lembodiment of the invention, structure is also provided for
¦hinging the arm relative to the boom structure to maintain the
¦longitudinal axis of the arm substantially horizontal as the boom
¦ is rotated in a vertical plane.
¦ In this embodiment of the invention, not only are the
; ¦ problems heretofore experienced with respect to ground clearance
; ¦ alleviated, but additionally the compensating moment provided by
the counterweight is maintained at a maximum by retaining the
¦ maximum moment arm through which the concentrated weight unit acts
¦ as the boom elevates. This configuration is to be contrasted to
¦ prior art units where the counterweight rotates with the boom
thereby reducing the effective moment arm through which the
counterweight acts. -~
¦ In this embodiment of the invention, the structure for
¦ maintaining the counterweight horizontal includes a mast extending
¦substantially perpendicularly from the boom, a first sheave system
attached to the top of the mast and a second sheave system
1 attached to the base. A cable extends from the counterweight and
¦ is entrained about the first sheave system and the second sheave
¦ system and attached to the boom whereby pivoting of the boom
¦ varies the length of the section of the cable system between
¦ the counterweight and the first sheave system to maintain the
¦counterweight horizontal as the boom is pivoted.
¦ In accordance with another embodiment of the invention,
~the struc ure for maintainirg the counterweight level during
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:t, rotation of the boom further includes a third sheave system
attached to the boom. In this embodiment of the invention, the
'! cable system extends from the counterweight and is entrained about
the first sheave system and multiply wrapped about the second and
third sheave systems whereby pivoting of the boom varies the
length of the section of the cable system between the
counterweight and the first sheave system to compensate for
pivoting of the mast with the boom to maintain the counterweight
horizontal as the boom rotates.
In accordance with still another embodiment of the
invention, a triangular structure has one corner rotatably
- attached to the underside of the boom with at least one sheave
attached to a second corner thereof and a bearing surface on a
- third corner for bearing against the underside of the boom as the
boom is pivoted upwardly. The sheave attached to the triangular
structure is adapted to receive line from the second sheave
system. This arrangement for maintaining the counterweight -
horizontal during rotation of the boom compensates for decreasing ~-
draw up of the cable system during high angles of rotation by the
boom.
In accordance with still another embodiment of the
invention, the structure for maintaining the counterweight
horizontal during rotation of the boom comprises a measuring
device for measuring the position of the counterweight relative to
ZS horizonta A servo syste~ is connected to the counterweight and
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- is operative in response to the measuring device to hinge the
counterweight relative to the boom in order to reposition the
counterweight to horizontal as the boom pivots.
In accordance with still another embodiment of the
invention, a winch is provided with a cable extending from the
winch to the counterweight. The winch is operative in response to
a device for measuring the angular position of the counterweight
relative to horizontal such that the winch is energized to draw up
and let out the cable in order to maintain the counterweight level
as the boom rotates.
In accordance with still another embodiment of the
present invention, a cable is provided extending along the boom to
its load bearing end. The cable is adapted for supporting the
load to be carried by the boom. A winch mechanism is supported by
- 15 the base structure and is adapted for controlling the length of
the cable to raise and lower the loads attached thereto. The
hoist mechanism comprises two drums with multiple straight grooves
about which the cable is alternately wrapped. The rotational axis
of one drum is parallel to the axis of the second drum. The
- 20 multiple wraps of the cable system about the drums generate
sufficient traction to raise the loads attached thereto.
In accordance with still another embodiment of the
present invention, the hoist mechanism for controlling the
movement of the load bearing cable includes a first drum having
multiple grooves therein and a second drum having multiple grooves ~-
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, ¦ therein. The axis of rotation of said first drum is canted
relative to the axis of rotation of said second drum and the cable
is alternately wrapped between the grooves of the first and second
drums. At least one of the drums is driven to draw in or let out
cable to raise or lower the load carried by the cable.
: In another embodiment of the invention, the first and
second drums are maintained in a side by side relation and the
rotational axis of the first drum is canted relative to the
~ rotational axis of the second drum such that the grooves at the
: 10 top of the first drum are in alignment at the top with
corresponding grooves in the second drum and grooves at the bottom
of the first drum are in alignment at the bottom with grooves
adjacent to corresponding grooves of the second drum. In this
arrangement, the cable may be wrapped around the first and second
drum consecutively through each of the grooves formed therein with
a minimum of induced side loading or torsion being imparted to the
cable. This is a result of the particular alignment of the
grooves in the drums such that the cable follows a path in which
suCcessiv rooves are aligned one with the other.
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¦IDESCRIPTION OF ~HE DRAWINGS -
For a more complete understanding of the present inven-
tion, and for further details and advantages thereof, reference
is now made to the following description taken in conjunction withl
¦¦the accompanying drawings in which: I :
ll FIGURE 1 is a side elevational view of an embodiment of
¦Ithe crane embodying the present invention;
FIGURE 2 is a side elevational view of the embodiment
illustrated in FIGURE 1 showing the boom rotated upwardly; .
FIGURE 3 illustrates one embodiment of the system for
.1 maintaining the counterweight in a horizontal configuration during
. rotation of the boom; :
. ¦¦. FIGURE 4 shows the boom in an intermediate rotational
stage with the counterweight maintained in a horizontal position
by the leveling system;
~ FIGURE 5 shows the boom in its maximum up position with
., the counterweight maintained in a horizontal position by the
leveling system;
j FIGURE 6 illustrates an alternative embodiment for
.. 20 maintaining the counterweight level during rotation of the boom; -.
: IFIGURE 7 is a side elevational view of a preferred
embodiment of the crane of the present invention;
FIGURE 8 is a sectional view taken along line 8-8 of
~; ¦ FIGURE l;
1l ~ FIGURE 9 is a sectional view taken along line 9-9 of
.~ FIGURE ~ showing the retraction mechanism for withdrawing the
counterweight into the boom;
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FIGURE 10 is a schematic view of the hoist winch
mechanism of the present invention;
: FIGURE 11 is a top view of a portion of the hoist
winch mechanism of FIGURE 10 showing the winch mechanism of
the present invention;
FIGURE 12 is a side view of the portion of the winch
mechanism shown in FIGURE 11;
FIGURE 13 is a top view of an alternate embodiment of
a portion of the winch unit used in the present invention; --
FIGURE 14 is a side view of the portion of the winch
mechanism illustrated in FIGURE 13;
FIGURE 15 illustrates the arrangement of the present
~ invention through which the crane may be self-hoisted;
- FIGURE 16 illustrates the crane mounted for hoisting
on the structure shown in FIGURE 15; -
.- FIGURES 17 and 20 illustrate the crane of the present
. invention mounted on a self-powered motorized vehicle;
FIGURE 18 illustrates the crane prepared to be moved
.i on the motorized vehicle of FIGURE 17;
. 20 FIGURE 19 illustrates the hydraulic circuit for a
',r shock overload protection means used on the crane of the
present invention;
FIGURE 21 illustrates an alternative embodiment of
~- the winch mechanism illustrated in FIGURES 10 through 14;
FIGURE 22 is a partial section view of the winch
`~ mechanism taken along line 22-22 of FIGURE 21 showing only
. the drums and their relative alignment; and
FIGURE 23 illustrates the winch mechanism shown in
FIGURE 21 mounted on a crane.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGURE 1 illustrates a side view of a crane 30 embodying
; the present invention. Crane 30 includes a base structure 32
rotatably secured to a foundation structure 34. Extending from
base 32 is a superstructure 36, to which a boom 42 is attached.
Superstructure 36 is rigidly attached to base 32 and boom 42
pivots at the upper end by axis shaft 44. Support member 40, in
; a preferred embodiment of the invention, is a hydraulic ram
including a ram cylinder 46 and a ram piston 48 which is joined to
a clevis 50. One end of hydraulic ram cylinder 46 is rotatably
; attached to base 32 while clevis 50 is rotatably pinned to a lug
51 extending from the underside of boom 42 by pin 52.
Joined at one end of boom 42 is a boom extension 70
, consisting of elements 70a and 70b. The boom extension 70a is
removably joined to main boom 42 by suitable fasteners 78 and
boom extension 70b is joined to boom extension 70a by the same
fasteners. The end of boom extension 70b remote from boom
extension 70a is adapted with a sheave system 90. Sheave system
; 90 is rotatably secured to boom extension 70b about rotational
axis shaft 92.
Extending upwardly from main boom 42 is mast 100 which
is rotatably pinned to boom structure 42 along the top surface
thereof by axis shaft 102. The end of mast 100 remote from boom
42 is adapted with a juncture plate 104. Removably secured
between juncture plate 104 and the rearward end of boom 42 is mast
support m Oer 110. ~ast support member 110 is joined between
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boom 42 and juncture plate 104 by suitable pins 112 and 114,
respectively. A cable assembly 116 is fixedly attached between
juncture plate 104 and the most forward end of boom 42 by pins
118 and 120, respectively. Intermediate of the points of
connection between juncture plate 104 and boom structure ~r is
lia turn buckle 122 for appropriately adjusting the tension on
~¦cable 116.
Similarly, a cable assembly 130 extends from juncture
plate 104 at the uppermost end of mast 100 and the most forward
l end of boom extension 70b in order to transmit loading from the
l boom through the mast and into the base structure. Cable assembly
; 130 is joined to juncture plate 104 and boom extension 70b by pin
¦132 and connecting strap 134, respectively. In a preferred
lembodiment of the invention, connecting strap 134 is joined to
boom extension 70b at axis shaft 92. A tensioning mechanism 136
is connected by suitable fasteners 138 and 140 intermediate of
cable 130 and connecting strap 134 to permit selective tensioning
of cable 130.
¦ A counterweight assembly 150 is hingedly attached at pin
~shaft 152 to an I beam section 154 which is slidable within the
boom 42. Counterweight assembly 150 is composed of an I beam
~section 156 rigidly attached to a weighted end unit 158. I beam
Isection 156 is adapted with guide ears 160 for aligning the
; counterweight I beam section 156 with I beam section 154.
! I beam section 156 includes an upper cap 156a, a lower
cap 156b and a web 156c. Similarly, I beam section 154 includes
ilan upper cap 154a (not shown), a lower cap 154b (not shown) and a
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¦web lS4c. A cable system 170 is joined to weight unit 158 by
¦ coupling member 172 and pin 174. Cable system 170 extends around
¦ a sheave system 180 (not shown) positioned adjacent to juncture
¦ plate 104 at the uppermost end of mast 100. Sheave system 180
¦ has as its rotational axis shaft 182.
Cable system 170 extends around sheave system 180 and is
i~ connected to boom 42 through a triangular take-up structure 184 in
a manner to be hereinafter described in detail. Triangular
take-up structure 184 consists of a rigid structure including --
sides 186, 188 and 190. One end of side 186 is rotatably pinned
by suitable pin 192 to boom 42. The opposite end of side 186 is
adapted with a sheave system 196, to be hereinafter described in
greater detail. A bearing pad 198 is fixedly attached at the
juncture of sides 188 and 190 and is adapted for bearing against
the lower side of boom 42 during operation of the unit as will
hereinafter be described in greater detail~
Also illustrated in FIGURE 1 and to be described here-
inafter in further detail, is hoist cable 200 extending from the
load bearing end of boom extension 70b and about sheave system 90. - -
Attached to the end of hoist cable 200 by pin 201 is hoist block
202 adapted with hook 204.
Referring again to FIGURE 1, a take-up reel 206 is
attached for rotation from the boom 42. Fixedly attached to base
32 is a cab structure 208 from which the crane unit is operated.
Crane 30 is supported for rotation about a vertical axis
from base structure 32 on foundation structure 34. In a preferred
embodiment of the invention, foundation structure 34 is adapted
~("` 10903ZJ
with teeth 210 about the circumference thereof. Extending from
base structure 32 is a rotatable pinion wheel 212 which mates with
teeth 210 on foundation structure 34. By rotating pinion wheel
212, base structure 32 and thus crane 30, may be selectively
rotated about a vertical axis, relative to foundation structure
34.
Referring to FIGURE 2, crane 30 is shown with boom 42
pivoted upwardly about axis shaft 44. As is illustrated in FIGURE
2, upward rotation of boom 42 is accomplished by extending ram
,` 10 piston 48 thereby causing rotation of the boom about axis shaft
44. As mast support strut 110 and support cables 116 and 130,
each extending from juncture plate 104 to points along boom 42 are
each fixedly attached to the boom, the relationship of mast 100 to
boom 42 remains unchanged as boom 42 is rotated upwardly. Due to
the leveling mechanism, to be hereinafter described in greater
detail, the portion of counterweight cable system 170 between the
weight unit 158 and the sheave system 180 is automatically
shortened as boom 42 is raised. The arrangement for automatically
taking up the counterweight cable system 170 is so designed as to
maintain the longitudinal axis of counterweight assembly 150
horizontal throughout all rotational positions of the boom.
One embodiment of the counterweight cable system 170
is illustrated in FIGURES 3, 4 and 5. Referring to FIGURE 3,
the superstructure 36 is shown supporting boom 42 at axis shaft
44. Mast 100 and mast support strut 110 are shown extending
from boom structure 42 as hereinbefore described.
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Counterweight assembly 150 is shown hingedly attached at
pin 152 to I beam 154 slidably engaged within boom structure ~.
Weight unit 158 attached to the end of counterweight I beam 156 is
shown connected to leveling cable system 170 by coupling member
172 and pin 174. ~ -
¦ Rotatably attached at axis shaft 182 is sheave system
180. Similar sheave systems 220 and 222 are rotatably positioned
about axes 224 and 226, respectively, on boom 42, and sheave
Isystems 230 and 232 are rotatably attached to superstructure 36 by
¦axes pins 234 and 236, respectively. Triangular take-up structure
¦184, consisting of side members 186, 188 and 190, is joined at one
lend of side 186 by pin 192 to ear 194 extending from the lower
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I I portion of boom structure ~. The opposite end of side 186 is
¦ adapted with sheave system 196. The corner at which sides 188
¦ and 190 of triangular take-up structure 184 are connected is
adapted with bearing pad 198 as hereinabove described. The sheave
¦ systems 196 and 232 are adapted with multiple parallel sheaves
having a common axis of rotation.
Cable system 170 is attached at one end to weight unit
158 of counterweight assembly 150 by coupling member 172 and pin
174. Cable system 170 extends from weight unit 158 and is
entrained alternately around sheave systems 180, 220, 222, 230 and
196. Cable system 170 is multiply wrapped about sheave systems
232 and 196 and is thereafter fixedly attached adjacent sheave
system 196 by coupling member 240. Referring to FIGURE 3, it may
be seen that the length of cable system 170 is such that the
longitudinal axis of counterweight assembly 150 is in line with
10903Z3
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:~ longitudinal axis of boom 42 when boom 42 is in the horizontal
; position.
J: FIGURE 4 illustrates the boom in a rotated position and
shows the resultant effect on cable system 170 and counterweight
. 5 assembly 150. Referring to FIGURE 4, it may be seen that the
portion of cable system 170 between weighted end unit 158 and
¦ sheave system 180 at the upper end of mast 100 is shortened as a
result of the movement of sheave system 196 with the rotation of
. boom 42. As boom 42 rotates upwardly in a horizontal plane,
sheave system 196, attached to the boom 42 by way of triangular
~3 take-up structure 184 moves upwardly with boom ~ and away from
sheave system 232 attached to base support member 38. As
illustrated in FIGURES 3 and 4, cable system 170 is wrapped three
. times about sheave systems 196 and 232. As a result, line 170 is
drawn three times the distance sheave system 196 is moved from
sheave system 232. This take-up in cable system 170 in
conjunction with the arrangement of the other sheave systems about
which cable system 170 is entrained, hinges counterweight assembly
150 about axis pin 152 to maintain the counterweight horizontal
throughout the rotation of the boom.
Referring to FIGURE 5, the boom has been rotated to its
. uppermost rotational position moving sheave system 196 further
from sheave system 232 and thereby effectively shortening cable
: system 170 to maintain the counterweight assembly 150 horizontalthroughout the upper movement of the boom. In the rotational
positions between that illustrated in FIGURE 4 and that
illustrat in FIGURE 5, it may be seen that triangular take-up
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structure 184 has been rotated about its point of connection at
pin 192 toward the lower side of the boom 42 such that bearing pad
198 contacts the lower surface of boom 42. In this way, sheave
196 is maintained a sufficient distance away from boom 42 and
slightly further from sheave system 232 than in the configuration
where the triangular take-up structure is absent. This arrange-
ment results in the additional take-up of the length in cable
system 170 necessary in the upper rotational stages of the boom
in order to maintain the counterweight assembly 150 horizontal.
FIGURE 6 illustrates an alternative embodiment of the
present invention wherein the counterweight assembly is maintained
, in its level configuration by a leveling sensor 244 which
energizes a winch unit 246 to draw in and let out cable system 170
to maintain the counterweight assembly 150 level during the
movement of the boom. Referring to FIGURE 6, winch unit 246 is -
adapted for receiving one end of cable system 170. In this
' embodiment, winch unit 246 is substituted for,sheave systems 230
and 232 and triangular take-up structure 184. Leveling sensor 244
is attached to web 156c of I beam assembly 156 by suitable means.
Leveling sensor 244 is of the type capable of sensing movement of
, counterweight assembly 150 and of generating a signal when the,
longitudinal axis of I beam section 156 moves out of line with the
horizontal. Appropriate circuitry (not shown) is interconnected
between sensor 244 and winch 246 for relaying the signal trans-
mitted by sensor 244. Winch 246 is operative in response to the
, signal emitted by sensor 244 and is appropriately controlled to
~, draw in or let out cable system 170 whenever counterweight
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assembly 150 rotates from the horizontal to maintain the
counterweight assembly level at all times.
~: I Thus, in this embodiment, cable system 170 extends from
the weight unit 158 around sheave system 180 and is attached to
winch 246. As the boom is rotated in a horizontal plane, sensor
244 generates an appropriate electrical signal which in turn
energizes winch 246. In this way, line 170 is drawn in and let
out in accordance with the signal from sensor 244 to maintain
~ the counterweight assembly level throughout movement of the boom
;~ 10 structure. Therefore, in the embodiment illustrated in FIGURE 6,the purely mechanical method illustrated in FIGURES 3-5 for
maintaining the counterweight horizontal is replaced by an
electrical servo system operating a winch unit to draw in and let
; out the counterweight cable system as necessary to maintain the
counterweight horizontal.
." FIGURE 7 illustrates a side view of a crane 700
constructed in accordance with one embodiment of the present
invention. Crane 700 includes a base structure 32 secured to a
foundation 34. A superstructure 36 is mounted on base structure
32 which rotates about a vertical axis during operation of the
crane. A boom 42 is supported from superstructure 36, being
; pinned at its rearward end to the apex of superstructure 36 by
axis shaft 44 and supported forwardly thereof by a hydraulic
cylinder 46. Cylinder 46 is attached at clevis fitting 38 on the
base 32 and ear 51 extending from boom 42 by axes pins 50 and 52,
respectively.
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A mast 100 is pivotally pinned to main boom structure
42 along the top surface thereof by axis shaft 102 and extends
¦ upwardly therefrom. The end of mast 100 remote from boom 42 is
adapted with a juncture plate 104. A hydraulic cylinder 736 or
loptionally a mast support member 110 is connected between the main
'boom structure 42 by axis pin 112 and to juncture plate 104 by
¦~axis pin 114. While FIGURE 7 illustrates single hydraulic
i cylinders 46 and 736, it will be understood that in the preferred
embodiment of the invention, these elements are used in pairs with
elements of each pair positioned on opposite sides of the main
` boom structure and operating in unison one with the other.
A boom extension 70 extends from boom 42 and is attached
thereto by axis shaft 752. The end of boom extension 70 remote
~ from main boom structure 42 is adapted with a sheave system 90
; 15 rotatably secured to boom extension 70 by rotational axis shaft
, 92. A strap 134 has one end supported to axis shaft 92 of boom
extension 70 and the opposite end attached by way of coupling
member 138 to a cable assembly 130 which supports the end of boom
extension 70 remote from main boom structure 42 from juncture
plate 104 and mast 100 by way of coupling 132.
As has been discussed previously with respect to other
- embodiments of the invention, main boom structure 42 can be
, ~ constructed to receive a counterbalance unit which may be
telescoped outwardly to counterbalance the weight supported
i from the working end of boom extension 70.
¦ As will be appreciated by examination of FIGURE 7, the
structule s designed to provide direct load paths through mast
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100 and member 110 through boom 42 into superstructure 36 and
I hydraulic cylinder 46. In this way, bending stresses which would
¦¦normally be introduced into boom 42 are minimized with the load
Ibeing substantially carried directly into superstructure 36.
~ Hydraulic cylinder 46 operates to pivot boom 42 about
axis pin 44 by extension and retraction in the conventional manner.
~IAdditional1y, hydraulic cylinder 736 serves to permit pivoting of
j boom extension 70 about axis pin 752 when a shock load greater
¦ than the rated capacity of the crane is imposed on the boom. The
¦ hydraulic circuit and the operation of this shock overload
protection system is described hereinafter in FIGURE 19.
FIGURES 8 and 9 illustrate the mechanism for retracting
¦and extending the counterweight into and out of the boom. FIGURE
18 is a sectional view taken along lines 8-8 of FIGURES 1 and 9.
` 15 FIGURE 9 is a sectional view taken along lines 9-9 of FIGURE 8.
Referring to FIGURE 8, the boom structure 42 is adapted with ¦
¦llongitudinal support members 62 and 64. Interconnected between
¦¦longitudinal support members 62 and 64 are transverse support
,¦members 62a and 64a. As is shown in FIGURE 9, lugs 280, 280' (not !
¦¦shown), 282 and 282' (not shown) extend from transverse support
¦members 62a. Extending through lugs 280 and 280' and through 282
and 282' are axes pins 284 and 286, respectively. Rollers 288 and
¦ 290 are suspended on axes pins 284 and 286, respectively, and
l¦between lugs 280 and 280' and 282 and 282', respectively.
25 ~ ~I Similarly, lugs 292~and 292' and 294 and 294' (not
¦Ishown) extend upwardly from lower transverse support structure
¦¦64a to support axes pins 296 and 298 and rollers 300 and 302, ¦
llrespectively. I
I Il
!
I .
I - 22 - -
11 1090323
Rollers 288, 290, 300 and 302 have a constant diameter
¦¦cylindrical midsection with flanges at either end for accepting
` - ¦! upper and lower caps 156a and 156b of counterweight I beam 156.
Counterweight I beam 156 rides on rollers 300 and 302 and below
~ ¦I rollers 288 and 290 and is guided within boom structure 6~ by
these rollers during the retraction and extension of the counter-
¦¦weight assembly.
¦i Referring to FIGURES 8 and 9, and specifically to FIGURE
~¦9~ chain 310 is connected at each end to counterweight assembly
1!150 and is entrained about sprocket wheels 312, 314 and 316.
¦Referring to FIGURE 8, it may be seen that sprocket wheel 312 is
rotatable about shaft 320 which is supported by a support bracket
¦322 extending downwardly from transverse frame member 62a and
attached thereto by suitable fastening means such as bolts 324.
~Shaft 320 is rotatably received within support bracket 322 by
bearing assemblies 326 and 328, respectively. Although not shown,
, Isprocket wheel 316 is similarly supported within support brackets
¦322. Sprocket wheel 314 is driven by a suitable motor 330 which
is suitably attached to support bracket 322, such as by bolts 332
¦1 and 334.
Thus, by energizing motor 330 to rotate sprocket wheel
, 1¦314, chain 310 may be driven forward or aft. By rotating sprocket
?~ I!wheel 314 counterclockwise (as viewed in FIGURE 9), counterweight
~assembly 150 is moved to its extended position out of the boom.
jllSimilarly~ by rotating sprocket wheel 314 clockwise, as viewed in
FIGURE 9, chain 310 is made to draw counterweight assembly 150
~¦into the boom structure.
i1 ~
,. ~ Il I
.. ' 1'1 i
- 23 -
.
~ "` ~0903Z3 ~ I
.,
¦ Also illustrated in FIGURES 8 and 9 is a locking
mechanism 350 for locking the counterweight assembly either in the !
fully extended or fully retracted position and for preventing the
operation of the crane assembly whenever the counterweight
assembly is intermediate of these positions. Locking assembly 350
¦includes a bracket 352 rigidly attached to the boom structure and
¦ia lock plate 354 rotatably hinged to transverse frame structure
164a. A hydraulic cylinder 360 is pinned between bracket 352 and
!plate 354, respectively. The lock plate 354 is so positioned as
¦to mate with notches within the lower cap 156b of counterweight I ¦
beam 156 when the counterweight assembly is either in the fully
¦ extended or fully retracted position. By actuating the hydraulic
cylinder 360, the lock plate 354 is made to engage the notch
~ within the lower cap 156b of the counterweight I beam 156 thereby
; 15 restraining the counterweight assembly from movement axially along
- the boom structure. A support plate 370 extends upwardly and is
fixedly attached to transverse frame elements 64a. Support plate
370 provides an additional restraint to lock plate 354 and
provides more rigidity thereto when in the locked position.
When lock plate 354 is in the locked position, that is,
sufficiently rotated such as to engage the notch within the
counterweight I beam 156, it makes contact with electrical switch
, 376 closing the circuitry through the crane power source and
permitting operation of the unit. Otherwise, the power source to I
r~ 25 the crane system is always open, thereby preventing operation of I -the unit whenever the counterweight system is not in the locked
position.
'.' ~
'~ I ~ :
I - 24 -
.
f?
-: ` 10903Z3 ~- I
. . I
Referring to FIGURE 9, the shaft 358 on which lock plate
¦ 354 hinges is seen to be supported at both ends by transverse
. ¦frame members 64a.
l I While only four roller supports are illustrated in
-; 5 ,IFIGURE 9, it will be understood that any number of upper and lower
~L~ l,roller supports may be spaced along boom structure ~ as is
necessary to accommodate the movement of counterweight assembly
150 into and out of the boom structure.
Thus, the present invention discloses a crane system
wherein the counterweight is pivotally hinged from a section
. fixedly secured to the boom. The counterweight is automatically
hinged as the boom is rotated upwardly in a vertical plane such
that the longitudinal axis of the counterweight remains horizontal
throughout the movement of the boom. Because the counterweight
~-~ 15 ¦structure is maintained level throughout the angular rotation of
the boom, ground clearance problems are eliminated in that the
~counterweight maintains substantially the same position relative
to the ground and other surrounding structures as the boom rotates
- Not only are the problems with respect to ground
clearance of an extended counterweight attached to the boom thus
alleviated, but additionally the effectiveness of the compensating
moment provided by the counterweight is maintained at a maximum by
retaining the maximum moment arm through which the weight of the
~ counterweight assembly acts. This configuration is to be
! contrasted to prior art units where the counterweight rotates with
the boom as the boom rotates upwardly thereby effectively reducing
- ¦the moment arm of the counterweight. Additionally, the present
I !
- 25 - ~
('` I 10903z;~ --
invention discloses structure for permitting the retraction of the
counterweight assembly into the boom for adapting the unit for use
- in tightly confined areas and for preparing the unit for relocation.
Further, the manner in which the counterweight moment is
carried to the base structure as well as the manner in which the ¦
¦ moment produced by the load attached to the boom is directed into
` ¦ the base is significant. These loads are substantially supported
through cable system 170 and cable assembly 130. Further, the
load bearing paths represented by cable system 170 and cable
assembly 130 are not interrupted by the hinging of counterweight
assembly 150 in that cable system 170 provides a continuous load
path from weighted unit 158 around the uppermost part of mast 100.
While the tension loads on the mast from the counterweight and the
; 15 boom tend to counterbalance each other, the vertical load appliedthrough cable system 170 and cable assembly 130 into mast 100 are
; directed into the base structure therebelow. By so directing the
~; loads introduced by the counterweight assembly and the load
carried by the boom, the loading is more directly applied to the
, 20 base structure.
FIGURE 10 illustrates in a perspective schematic view
the winch mechanism of the present invention. In accordance with
the present invention, hoist cable 200 is entrained about sheaves
90 and 400 and multiply wrapped about drums 402 and 404. Drums
402 and 404 each have a plurality of grooves 402a and 404a,
respectively. The rotational axis of drum 402 is appropriately
spaced from and parallel to that of drum 404. Cable 200 is
'
~- - ' - ', ' -
oso~
multiply and alternately wrapped between drums 402 and 404 such
that the cable makes a single 180 degree wrap around any groove
402a or 404a. Cable 200 emerges from the drums 402 and 404 and
passes around sheaves 410 and 412 and thereafter extends to
take-up reel 414. Take-up reel 414 has an appropriate motor
attached thereto (not shown) for applying a continuous nominal
, tensioning load, for example 50 to 60 pounds, to cable 200. Drums
402 and 404 are suitably attached for rotation on the base
;;~ structure 32 of the crane assembly. Sheaves 90, 400, 410 and 412
~ and take-up reel 414 are each appropriately suspended for rotation
, ~ from boom structure ~. Either or both drums 402 and 404 may be
driven to provide the cable tension required for lifting loads.
If both drums 402 and 404 are driven-in the same direction of
,~ rotation the cable 200 will be wrapped around them in the mannerillustrated. If the drums 402 and 404 are driven in opposite
directions of rotation the cable 200 will be wrapped around the
drums 402 and 404 in a figure eight fashion. If only one of the
drums 402 or 404 is driven the cable 200 may be wrapped around
the drums in either 180 degree or figure eight fashion.
FIGURE 11 illustrates a top view of opposed drums 402
and 404. As is best seen in FIGURE ll, drum 402 is rotatable on -
; shaft 420 and drum 404 is rotatable on shaft 422. The drums are
maintained with their axes of rotation in a spaced parallel
relationship by support housing 424 which encircles the two drums
and supports the ends of shafts 420 and 422. Referring to FIGURES
11 and 12, sprocket wheel 426 is mounted for rotation with shaft
.
.
. . .
10903~
420 and sprocket wheel 428 is mounted for rotation with shaft 422.
Sprocket wheels 426 and 428 are mounted on shafts 420 and 422
outside of support housing 424. Sprocket wheels 426 and 428 are
coupled for rotation by endless chain 430. As may be seen in
FIGURE 11, an appropriate motor 432 engages shaft 422 opposite the
end on which sprocket wheel 428 is mounted. Motor 432 may be
powered by any suitable means. In preferred embodiments of the
invention, the motor is either electrically or hydraulically
powered. Thus, by rotating shaft 422, both drums 402 and 404 may
be selectively rotated either in the forward or reversed
direction.
Wedge 434 is slidably positioned adjacent drum 404 and
may be selectively engaged or disengaged by handle 436 between
drum 404 and support housing 424. As cable 200 lS wrapped such
that the cable is let out by the counterclockwise rotation of drum
404, as seen in FIGURE 12, wedge 434 provides a fail-safe locking
i function by preventing the extension of cable 200 when the wedge is engaged between drum 404 and support housing 424.
FIGURES 13 and 14 illustrate an alternative embodiment
of the winch mechanism illustrated in FIGURES 11 and 12. In this
embodiment, cable 200 is entrained around the successive grooves
a~ m ~
of drum 402~in a "figure eight" wrap design. Additionally,
shafts 420 and 422 of drums 402 and 404, respectively, are
adapted with gears 440 and 442 which are engaged with each
other.
.
' . '
-~ ~ 1090~
Thus, by multiply wrapping cable 200 about the drums 402
and 404, and by applying a nominal take-up load on the end of
cable 200, sufficient gripping strength may be induced between the
cable and the drums to draw in and extend cable 200 under its
maximum load without experiencing any slippage of the cable
,` relative to the assemblies. By using the figure eight wrap
illustrated in FIGURE 14, the gripping force between cable 200 and
drums 402 and 404 is increased substantially so that fewer wraps
may be employed.
'3' 10 The advantages in using the arrangement illustrated in
FIGURES 10 through 14 are numerous. Initially, it will be
appreciated that cable 200 is not at any time wrapped over itself
while under a load as in prior art hoist drums. Thus, the
substantial wear experienced in prior art devices by overIaying
cable on the drum is eliminated. Further, the need for attempting
:- to prevent cross-winding of the cable onto the drum is eliminated
as there is no possibility of the cable being wound on itself.
Additionally, in the prior art systems where the take-up
f the load bearing cable is on a single drum, the effective
iameter of the drum would naturally vary as the cable was wound
nto the drum. In the present invention, the drum diameter is
onstant and thus the torque necessary to turn the drums will
emain constant throughout the operation of the unit. Likewise,
in that the torque necessary to turn the drums will remain
onstant it will be directly related to the load on the cable.
~Thus, whe e the spool is actuated by a hydraulic powered system, a
.''` ~
i - 29 -
. , .
`~` 1(~903Z3
l measure of the hydraulic line pressure will be a direct indication
; of the working tension on the cable. The cable load value is of
substantial importance both in regard to the capabilities of the
crane as well as in determining what the weight is of the load
being hoisted. Thus, the present hoisting mechanism provides a
ready means for generating a reading of the load being carried
by the cable as well as for eliminating problems heretofore
experienced with respect to wear on the cable and the torque
required to draw in the cable.
FIGURE 15 illustrates a structure through which the
crane system may be self-hoisted to a desired working height. The
structure includes a main frame including legs 500, 502, 504 and
c~o~ sh~w~)
~ 506~which are supported by transverse struts 508, 510, 512 and
; 514. Slidably engaged within the main frame is a cage structure
516 including longitudinal legs 518, 520, 522 and 524 and
transverse struts 526, 528, 530 and 532. The slidable cage ~ -
structure 516 is adapted at each end of its eight corners with a
guide bracket 534 which mates with a groove in the legs of the
main frame to permit the cage structure 516 to slide longitudi-
nally within the main frame. Cage structure 516 is adapted with
corner brackets 540 and 542 at opposed lower corners. Sheaves
544 and 546 are attached for rotation about a horizontal axis
through corner brackets 540 and 542, respectively, about axes
pins 548 and 550, respectively.
A cable 551 is attached at its ends to the uppermost
diagonally opposed corners 552 and 554 of the main frame through
: corner plates 556 and 558 by suitable fasteners 560 and 562,
.
. .
` .` ~ 10~0323 ---
; respectively. Cable 551 is entrained about sheaves 544 and 546
and adapted for attachment to hoist block 202 extending from the
crane assembly. The crane structure is mounted on slidable cage
structure 516. It may be readily recognized that by applying an
¦ upward force at the midpoint of cable 551, cage structure 516, and
thus the crane assembly itself, is pulled upwardly relative to the
¦ main frame.
¦ FIGURE 16 illustrates the crane moving upwardly within
the main frame on cage structure 516. The crane has its boom in
the most raised position, the slidable counterweight in its
retracted position with the mast folded against the boom in order
to clear the main frame in which the crane is elevated. It may
also be seen that when the crane is raised to the top of the main
frame structure, additional surrounding frame structure may be
assembled. Thereafter, the cable arrangement earlier described
with respect to FIGURE 15 may be employed to pull the crane to
higher levels as the main frame structure is extended. Thus, the
crane may build its own tower and hoist itself to the top without
any assistance from auxiliary equipment.
When the crane is being moved or is in operation near an
: adjacent interfering structure, the counterweight of the present
invention may be retracted into the boom as shown. With the
- I counterweight retracted, the boom may be rotated as when the
counterweight is extended except without the benefit of the
counterbalancing moment produced by the counterweight when in the
extended position. The geometry of the counterweight leveling
system is o srranged that the crane may be rotated to its maximum
- 31 -
10903ZJ -' ~
upward posi on without pUtting caùle Syste= 170 in tension.
Tension in cable system 170 is unnecessary as the leveling system
is non-functional when the counterbalance weight is in the
retracted position. Alternatively, cable system 170 may be
detached from the counterweight assembly when the counterweight
assembly is in the retracted positionD
a~d :Lo i~ st~ate,
FIGURE 17 illu~t-r~e~ the crane of the present invention
mounted on a self-powered motorized base vehicle 600. In this
embodiment of the invention, the structure of the crane is similar
to that described previously with respect to FIGURES 1-9. The
base structure 32 is mounted onto a frame 602 of motorized vehicle
600, and the crane structure is adapted for rotation about
vertical axis as well as pivoting about a horizontal axis as in
the previous embodiments.
The motorized vehicle 600 is adapted with a prime mover
~ 604 and a cab 606 supported by frame 602. The vehicle is movable
; on wheels 608. The vehicle may be stabilized by use of outriggers
; 610 positioned relative to the frame structure 602 for concen-
trating the load on foot pads 612 during operation of the crane.
FIGURE 18 illustrates the embodiment disclosed in FIGURE
7 wherein the crane has been positioned on vehicle 600 for
movement from one location to another. As is illustrated in
FIGURE 18, boom structure 42 is pivoted to its most downward
position, and mast 100 is likewise folded adjacent the boom
structure. Additionally, counterweight assembly 150 is in its
¦most re tra ted pO si tion within the ùoom s truoture.
~ I
.. ~ 32 -
:',
.
11 109032;~ s I
I I
¦l FIGURE 19 illustrates the hydraulic circuit for the
¦¦shock overload protection means shown in FIGURE 7. Hydraulic
¦Icylinder 736 includes a cylinder 770 and a piston 772. Piston
¦ shaft 774 extends out of the hydraulic cylinder and is attached as
¦¦hereinabove indicated to boom 42 by axis pin 112. The chamber 776
formed by cylinder 770 and piston 772 within hydraulic cylinder
¦¦736 is loaded with fluid under pressure and resists the extension '
¦of hydraulic cylinder 736 and therefore the loading applied to the
¦working end of boom extension 70. The volume of hydraulic fluid
contained within cylinder 736 is sufficient to maintain boom
extension 70 in line with boom 42 whenever the load applied to
the working end of boom extension 70 is within the rated load
capacity of the crane. Cylinder 770 is also fitted with a low -
pressure fluid maintenance line through which fluid is auto-
matically replenished during the operation as is necessary due to
leakage. A one way check valve 782 permits the flow of fluid
into cylinder 736, blocking the outflow of pressurized fluid.
An accumulator 784 communicates by way of tubing 786 to
I chamber 776 of cylinder 736. Accumulator 784 acts to restrain and
~ halt the downward movement of boom section ~ when a load greater
than the rated load is applied to the boom section during opera-
tion. Accumulator 784 is precharged with a gaseous medium 785, to
a pressure in excess of the pressure required to support cylinder
! 772 in reaction to a rated load on the end of boom section 70. A
i directional flow control 788 in line 786 between accumulator 784
¦ and cylinder 736 permits fluid to freely enter the accumulator
¦'whenever larger compressive loading exists within the hydraulic
` !! 1,
! ¦ !
ll - 33 -
``' ``` 1
Il :10903Z3 s
r i ¦
cylinder as a result of loading on boom 70 greater than the rated
loading. As may be seen in FIGURES 7 and 19, when the rated load
` jlimit is exceeded, the force exerted on hydraulic cylinder 736
overcomes the normal pressure maintained in the accumulator 784 -
thereby causing piston 772 to force hydraulic fluid from chamber
776 and into accumulator 784. As fluid is moved out of hydraulic
cylinder 736 and into accumulator 784, the downward movement of - -
~¦boom section ~~ is gradually halted as the pressure within the
cylinder-accumulator system becomes sufficient to counterbalance
the load carried by the boom extension. The directional flow
control valve 788 restricts the return flow of fluid from the
accumulator 784 dampening rebound action after the shock overload
on boom ~ is cushioned.
I A prime example of the advantage of the structure incor-
¦porated in the crane of FIGURES 7 and 19 is illustrated by the -
crane's operation to lift a load from a ship. In this mode of
; operation, the crane is normally fixed to a stationary platform
and the load is lifted on hook 204 from the ship. The hook is
. drawn in to lift the load approaching in weight the load limit for
ithe crane, from the ship's deck. When wave action causes the ship
to simultaneously descend in the water, a resulting dynamic load
, is applied to the crane increasing the effective load on the ¦ -
¦Icrane's structure as much as two to four times to actual weight of
¦ the cargo being lifted. While theie is some resiliency in the
1 cable and other structure supporting the main boom structure and
¦¦boom extension, this dynamic loading is in effect fully and imme-
¦Idiately applied to the crane's structure and would normally exceed
34 -
,, .
` ~ 10903Z3 -
¦ the structural limits of the crane. However, in the present
invention, this dynamic loading is cushioned by the extension of
hydraulic cylinder 736 and the resulting movement of boom
extension 70 downwardly. Subsequent to the cushioning of the
dynamic loading, the boom extension 70 is automatically reposi-
tioned relative to the main boom structure by the retraction of
cylinder 736.
Therefore, the embodiment illustrated in FIGURES 7 and -
19 provides a system which prevents impact loading which would
otherwise be suffered by the structure of the crane without the
movement permitted by hydraulic cylinder 736 and accumulator 784.
In the present structure, dynamic loading above the rated capacity
of the crane is accommodated by the movement permitted by
hydraulic cylinder 736 and accumulator 784 without exceeding the
structural limits of the crane.
.. FIGURE 21 illustrates an alternative embodiment of
, the winch mechanism illustrated in FIGURES 10 through 14. The
arrangement of FIGURE 21 includes drum assemblies 800 and 802
', mounted in housings 804 and 806, respectively. Drum assembly 800
includes a drum 808 having a plurality of parallel grooves 810
formed therein. Drum 808 is supported for rotation on a shaft 812
by bearings (not shown) received in bearing carriers 814 and 816
on opposite sides of drum 808. Bearing carriers 814 and 816 are
¦supported in housing 804 thereby supporting drum 808. Shaft 812
¦is driven by hydraulic motor 820 through a spring loaded,
hydraulic pressure released brake 822 and planetary gears (not
shown) housed in planetary gear box 824. Planetary gear box 824
':'. ~
.. ,..
" I 10903Z ~- ~
- ¦is attached to the side wall of support housing 804 by any
Isuitable means.
¦ Drum assembly 802 similarly includes a drum 830 formed
¦with a plurality of parallel grooves 832 and supported for
Irotation on a shaft 834 by bearings (not shown) housed in bearing
¦carriers 836 and 838 on opposite sides of drum 830. Bearing
¦carriers 836 and 838 are supported in housing 806.
Shaft 834 is driven by hydraulic motor 840 through a
spring loaded hydraulic pressure released brake 842 and planetary
l gears (not shown) housed in planetary gear box 844. Gear box 844
¦ is attached to the side wall of support housing 806 by any
suitable means.
¦ As is illustrated in both FIGURES 21 and 22, the axis of
. I rotation of drum 808 is canted or out of parallel alignment with
¦ that of drum 830. This relationship is achieved by the rotation
-~ I of support housing 804 relative to housing 806 about pivot
;, I assembly 850. Assembly 850 includes a bolt 852 which serves as a
¦ pivot pin and a nut 854 which serves to clamp the support housings
¦ 804 and 806 together.
¦ An adjustment assembly 860 is attached to the side walls
of support assemblies 804 and 806 for adjustment of the canted
¦ angle between the rotational axes of drums 808 and 830. Adjust-
¦ ment assembly 860 includes an arm 868 extending from housing 806
and arms 862 similarly attached to support housing 804. Arms
1 862 are formed with threaded holes which receive set screws 870
¦ and nuts 872. The angular relationship of housings 804 and 80Ç is
I controlled by the engagement of screws 870 against arm 868. This, ~ -
: ` ~0903Z3 -
," .
in turn, permits the angular adjustment of the rotational axis of
drum 808 relative to that of drum 830.
As is best illustrated in FIGURE 22, by canting drum
808 relative to drum 830, the grooves therein may be aligned
1 such that the cable wrapped thereon experiences little or no
side loading heretofore introduced into the cable because of
the relationship between the grooved drums. Where the axes of
rotation of the drums are parallel, the cable is wound around
the first groove of one of the drums to the first groove of the
second drum. In returning the cable from the first groove of
the second drum to the second groove of the first drum, the
cable must be angled out of the plane of the first groove of the
second drum to engage the second groove of the first drum. On
each successive wrap from the second drum to the first drum,
the cable must again be angled to engage the successive groove on
the first drum. As a result, side loading as well as torsional
..'r~ forces, are induced into the cable. In addition to the stresses
. resulting from such loading, this configuration causes the cable
to twist. In turn, where the load cable is used with a block in
multiple parts, as in FIGURE 23, the cable parts between the end
of the boom and the block will twist and render the winch
unusable.
As is illustrated in FIGURE 22, in the present invention
cable wound onto the first groove 832a of drum 830 leaves drum 830
at the rearward portion of the drum where the groove 832a is
substantially in line with groove 810a of drum 808. The cable
1eave= grc e 810r at the forward portion of drum 808 where the
.
',''
- 37 -
: l
(" ~ 10903Z:I ~
groove 810a is in line with groove 832b of drum 830. Thus, as the
cable is wound between drums 808 and 830, there is little, if any,
side loading introduced into the cable because of the substantial
alignment of the grooves between the sheaves.
The angle 0 between the rotational axes of drums 808
and 810 required to accomplish this alignment will naturally vary
with the diameter and groove spacing of the drums involved. The
cable is a wire rope made up of strands which are twisted tightly
.~ together. Each strand in turn is made up of a number of indivi-
dual wires which are twisted tightly together. The number of
strands, the number of individual wires per strand, the direction
of twist of the strands and the wires as well as other factors, -
affect the flexibility of the cable and the degree to which it
tends to untwist as it stretches under load.
The adjustment assembly 860 further permits the adjust-
ment of the angular relationship between the drums to be fine
` tuned until twisting in the cable is reduced to a minimum. This
fl adjustment permits compensation for the characteristics of cables
of different types and construction.
Thus, it may be found that to minimize the twist in the -
cable will in some cases require substantially exact alignment of
the drum grooves as shown in FIGURE 22. In other cases, a
somewhat over adjustment or under adjustment may be required. In
any event, pivot assembly 850 and adjustment assembly 860 will
permit the adjustment of drum 830 relative to drum 808 necessary
to minim cable wear and twisting.
- 38 -
lO90JZa
FIGURE 23 illustrates drum assemblies 800 and 802
mounted on a crane 900. Crane 900 includes a base 902 pivotable
on a foundation 904. Boom structure 906 is mounted on base 902 at
' pivot point 908 and through rotation cylinder 910 mounted to boom
- 5 906 at pin 912 and base 902 at pin 914. Crane 900 further
includes a mast 916 and mast support structure 918 which connects
the upper end of mast 916 to boom 906. Mast support structure 918
is attached to boom 906 by a fitting 918a and to the upper end of
mast 916 by a similar fitting 918b. Support cables 920 are con-
,~ 10 nected between the upper end of mast 916 and the load bearing end
of boom 906 by attachment 922.
Drum assemblies 800 and 802 are mounted on the rearward
end of boom 906 by bolts 930 and 932. A cable 934 has one end
attached to the load carrying end of boom 906 at point 936 and is
directed through block 938, around a sheave (not shown) rotatable
about an axis shaft 940 and through the lattice structure of boom
906 to drum assemblies 800 and 802. Cable 934 is guided through
the lattice structure of boom 906 by idler sheaves 942 and 946
supported for rotation from boom support members 948. Cable 934
is then wound successively between multigrooved drums 808 and 830
as shown in FIG~RES 21 and 22, then around idler sheave 950 and
back to take-up drum 952 which is attached to base 902 for
rotation about an axis 954. Cable 934 is guided from drum
assembly 800 to idler sheave 950 by an idler roller 956 attached
to boom 906 intermediate of the drum assemblies and idler sheave
950.
~ _39_ 1 ,
" ~0903Z3 -` ~
Cable 934 is carried around idler sheave 950 and then
back to be stored on take-up drum 952. By locating idler sheave
950 at a distance somewhat removed from take-up drum 952, the
fleet angle of the cable coming onto the take-up drum is sub-
stantially reduced permitting uniform winding of the cable onto
the take-up drum along the full width of the drum surface.
While the winch mechanisms illustrated in FIGURES 10-14
and the alternative embodiment illustrated in FIGURES 21-23, are
described as used on a crane, it will be understood that the winch
mechanisms have application in any and every apparatus where a -
cable, bearing a load, is drawn in or let out.
Thus, the present invention discloses a crane operable
on either a fixed or movable support structure. The crane
includes a base having a boom pivotally supported at one of its
ends from the base. The opposite end of the boom is adapted for -
receiving a load thereon. A mast is attached to the upper surface
of the boom and an upper tension member system substantially
relieving the boom structure of all bending and twisting loads so
that it works only under compressive loads. In another embodiment
a counterweight assembly is hingedly attached to the end of the --
boom supported from the base. This arrangement permits the
counterweight to be angularly rotated separate from the boom
during pivoting of the boom in a vertical plane. In this
embodiment of the invention, the crane is adapted with structure
for maintaining the extended counterweight structure substantially
level as the boom is pivoted on the base.
., . .
,.'~
'
- 40 -
,, . ,.
,i
~`
~09()3Z3
. In one embodiment of the invention, the structure for
maintaining the counterweight assembly level during rotation of
¦ the boom structure is a cable system extending from the counter-
, weight to the boom structure whereby the rotation of the boom
,. 5 draws the cable system such that the counterweight is maintained
in a level position. Alternatively, a leveling sensor is attached
to the boom and controls a cable take-up mechanism which draws in
and extends the cable system attached to the counterweight in
order to maintain the counterweight in a level configuration
during operation of the boom.
In still another embodiment of the invention, the
counterweight assembly is retractable and extendable into and out
of the boom structure. Structure is provided for moving the
counterweight assembly axially with respect to the boom structure
and for providing a locking mechanism which prevents the operation
:~ of the crane when the counterweight assembly is intermediate of
its most extended or retracted position.
In accorclance with still another embodiment of the
invention, the crane of the present invention is adapted with a
cable system extending from the weighted end of the counterweight
assembly over a mast structure positioned substantially over the
base of the unit and a cable system extending from the load bear-
ing end of the boom structure to the mast structure for more effec-
tively introducing loads and moments into the base structure from
both the counterweight assembly and the loads being lifted by the
~crane,
.
10903Z3 ~- ~
¦ urther, the present inventlon includes s more efficient
- and controllable hoisting system used by the crane to perform its
lifting function. The system of the present invention is one
which permits continuous and accurate take-up of the hoisting
cable while minimizing wear and damage to the cable heretofore
experienced in prior systems. The line pull and speed are not
affected by changing drum diameter as is the case with
conventional drum hoists. The hoist mechanism of the present
invention- also substantially reduces or eliminates torsional and
side loading normally induced in the cable by prior art traction
winch units. Further, the present invention discloses a method
- through which the crane may construct its own structure and
thereafter self-hoist itself to the top thereof.
Although preferred embodiments of the invention have
been illustrated in the accompanying Drawings and described in
the foregoing Detailed Description, it will be understood that
the invention is not limited to the embodiments disclosed, but
is capable of numerous rearrangements, modifications, and sub-
stitutions of parts and elements without departing from the
¦spirit o he invention.
,.
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