U.S. patent number 3,760,953 [Application Number 05/183,760] was granted by the patent office on 1973-09-25 for self-erecting crane to be towed by a truck.
Invention is credited to Egidio Cibin.
United States Patent |
3,760,953 |
Cibin |
September 25, 1973 |
SELF-ERECTING CRANE TO BE TOWED BY A TRUCK
Abstract
In a tower crane consisting of three articulated members, viz.
one lower member hinged to the slewing crane frame, a middle member
articulated to the said lower member and articulated to the
opposite end to the crane boom, the provision of an inextensible
cable fixed at one end to the said slewing frame of crane and to
the other end to the said middle member adjacently to the
articulation between the said lower member and middle member, said
inextensible cable being wound around an arcuated sector fixed to
the middle member, whereby swinging of the hinged lower member by a
capstan by means of a tackle device causes the self-erection of the
tower.
Inventors: |
Cibin; Egidio (Milan,
IT) |
Family
ID: |
22674174 |
Appl.
No.: |
05/183,760 |
Filed: |
September 27, 1971 |
Current U.S.
Class: |
212/297; 212/227;
212/298 |
Current CPC
Class: |
B66C
23/34 (20130101) |
Current International
Class: |
B66C
23/34 (20060101); B66C 23/00 (20060101); B66c
023/62 () |
Field of
Search: |
;212/46R,46A,46B,144 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,107,670 |
|
Mar 1968 |
|
GB |
|
965,025 |
|
Jul 1964 |
|
GB |
|
1,145,582 |
|
Oct 1957 |
|
FR |
|
Primary Examiner: Hornsby; Harvey C.
Claims
What I claim is:
1. A self erecting tower foldable crane to be carried by a truck,
of the kind consisting of a slewing crane frame rotatably mounted
on said truck, a lower hinged arm, a middle arm and a crane boom,
the lower hinged arm being pivoted to the said slewing, the middle
arm being articulated at one end to the lower arm and at the
opposite end to the crane boom, characterized by the provision
of a capstan fixed to the crane frame
of a main first cable,
of a pulley and a cable arrangement between the crame frame, first
cable and tackle means to swing the lower hinged arm
of a tackle means, operated by the main cable by means of said
capstan,
of a second cable fixed at one end to the slewing crane frame and
at the other end to the crane boom and operating for the
self-erecting of the boom.
of an arcuated sector fixed to the said middle arm adjacently to
the articulation of the latter with the said lower hinged arm,
and of a third inextensible cable extending around the arcuated
sector, one end of the said inextensible cable being fixed to the
said slewing crane frame and the opposite end of which being fixed
to the said middle arm adjacently to the articulation with the said
lower hinged arm, whereby swinging of the hinged lower arm by the
capstan by means of the said tackle device causes the self-erection
namely the opening out of the said middle arm from the said lower
hinged to form a tower for the boom.
2. Crane according to the claim 1. wherein adjacently to the
articulation of the said hinged arm with the said middle arm an
adjustable spring is fixed with one end to the middle arm, and an
L- profiled iron is welded to the lower hinged arm so as to
cooperate with the said spring in the aligned position of the said
lower hinged arm and middle arm and means are provided for
adjusting the reaction of the spring,the compression of the spring
in the aligned position of the lower arm and of the middle arm,
causing a reaction torque promoting the folding operation of the
crane.
Description
FIELD OF THE INVENTION
The invention relates to self-erecting tower cranes adapted to be
towed by a road vehicle.
The crane is of the kind comprising a lower arm hinged to a crane
frame rotatable about a vertical axis, a middle arm hinged at one
end to the lower arm and at the other end to a third arm operating
as a crane boom.
The object of the invention is to provide a crane of simplified
structure, wherein the number of parts are substantially reduced
and some parts perform a number of operations.
Furthermore, it is the object of the invention to provide a crane
that can be erected or unfolded in a matter of a few seconds.
SUMMARY OF THE INVENTION
According to the invention the crane is characterized by the
provision of an inextensible cable fixed at one end to the said
rotatable frame of the crane and to the other end to the said
middle arm adjacent to the hinge between the said lower arm and
middle arm, said inextensible cable being wound around an arcuate
sector fixed to the middle arm, whereby swinging of the hinged
lower arm by a capstan by means of a tackle device causes the
opening out of the said middle arm from the said lower hinged
arm.
According to a further feature one end of the cable of the tackle
device is fixed to the crane boom, and after the self-erection of
the crane and fastening of the lower arm and middle arm, and after
opening out of the crane boom by means of a third cable, the same
cable of the tackle device is utilized for vertically handling of a
load.
The crane capstan is provided with a flange with a notch for the
rapid coupling of the end of a branch of the cable for hoisting the
crane boom, so as a different inclination of the boom is rendered
possible by winding the said branch upon the capstan drum and by
fixing another portion of the cable for hoisting the crane boom to
the crane frame.
BRIEF DESCRIPTION OF THE DRAWINGS
The following is a detailed description of one embodiment of the
invention, by way of example only, with reference to the
accompanying drawings, wherein:
FIG. 1 is a diagrammatic side elevation of the crane in the folded
position,
FIG. 2 shows at a larger scale the portion A of FIG. 1 of the crane
boom,
FIGS. 3 and 4 show as FIG. 1 diagrammatically in side elevation the
crane in two intermediate stages during the self-erection,
FIG. 5 shows diagrammatically in side elevation the crane in its
final self-erected stage,
FIG. 6 shows at a larger scale the portion B of FIG. 5,
FIG. 7 shows at a larger scale the detail of the arcuated sector as
visible in the FIG. 1,
FIG. 8 shows at a larger scale the portion D of FIG. 5,
FIG. 9 is a longitudinal schematic section of the drive
capstan,
FIG. 10 is an elevation of the left side of FIG. 9 of the capstan
showing the detail of the stop notch,
FIG. 11 shows at a larger scale the detail of the free hook end of
the cable for modifying the inclination of the crane boom.
The crane essentially consists of a capstan 1 driven by an electric
motor, not shown, and mounted upon the crane frame 2, the latter
being supported and rotatable upon a wheeled carriage 3 about a
vertical axis. The foldable crane structure consists of three main
parts, namely the boom F, a middle arm G and a lower arm H
horizontally pivoted at 4 in the rotatable frame 2. The boom F and
the middle part G are hinged at 5 adjacent to a pulley 6 and to the
tip 7. The arm H and the middle arm G together form the tower of
the crane and are hinged at 8 as shown. The truck 3, adapted to be
towed by a road vehicle 9 is not particularly described since it is
well known in the art.
There is provided a tackle comprising a first set of sheaves 10
mounted at the bottom of the slewing frame 2, a second set of
sheaves 11 mounted adjacent to the free end of the pivoting arm H
and a first cable L represented by a chain-dotted line (-.-.-.-)
wound around the pulley 13, FIG.3, and around the pulley 14, the
latter being coaxial with hinge 8 and then wound around a pulley 6
and lastly around the sheaves 16 - 17, then fixed at 15 to the boom
F adjacent to the hinge 5. The cable L is of course fixed at its
opposite end to the capstan drum.
A second cable M, represented by a chaindotted line (-.-.-.-) has
one end fixed at 18 to the frame 2, while the other end is fixed at
19 to the end of arm G after having passed around the pulley 20,
along the arm H and engaging an arcuate sector 21 as shown in FIGS.
7 and 8. This sector 21 traverses a slot 22 formed in the U
profiled pivoting arm H when the crane is in the extended position,
FIGS. 8 and 5. A spring 23 is frictionally housed into a sleeve
fixed to the middle arm G and cooperates with a bracket 24 fixed to
the pivoting arm H, whereby, as soon as the arm G and H assume an
aligned position, the spring is compressed. This results in a
reaction in a clockwise direction, FIG. 8, which induces the
folding of the crane during the folding operation. A bolt 25 is
preferably provided for imparting the maximum reaction of the
spring. According to a further feature there is provided a third
cable N represented with full lines and fixed at one side at 18 to
the frame 2 and at the other side to the tip 7 and to the end of
boom F. From this cable N a branch N' is wound around the capstan 1
after having its end 26 hooked within the L-profiled notch 27 of
capstan drum flange 29. The branch N' is represented thus
-...-...-...-.
The operation of the crane according to this invention is as
follows:
When the capstan 1 is driven, the pivoting arm H is swung
anticlockwise as seen in FIG. 1 and at an intermediate stage the
cable M passes from a loose condition to a stretched condition.
Since the cable M is inextensible, and its length is constant and
the swinging of the hinged arm H strives to extend the cable M,
there occurs an opening out movement of parts G and H until an
alignment thereof is obtained. Also, the cable N at another
intermediate stage passes from a loose condition to a stretched
condition, FIG. 4, whereby an opening out movement of parts F and G
is caused as a consequence of the continuation of the swinging
movement of arm H and therefore of arm G. As soon as the vertical
alignment of arms G and H is obtained and resulting horizontal
positioning of the arm F, and the ends of parts G and H are locked
with one another by a clamping device, whereby the stable
connection of the parts is positively obtained.
When the capstan is driven in a reverse direction the crane eye
hook of the crane is lowered and subsequently hoisted for a
conventional handling of a load.
The operation of cable N' is now described, to obtain the
possibility of altering the position of the boom from a horizontal
position to an inclined position, as shown with chain-dotted lines
in FIG. 5. If the end 26 of branch cable N' is engaged in the
L-profiled notch 27 of the drum flange, driving of capstan and
therefore rotation of the drum will cause an anti-clockwise
rotation of the boom as viewed in FIG. 5 to the pre-established
position. For rendering this position stable it is only required to
engage a hole of a check plate K with a, not represented, pivot or
hook fixed to the crane frame.
From the foregoing it will be apparent that by means of a single
cable L not only the self-erection of the crane may be obtained but
even the vertical handling of the different loads. It is also clear
that by means of the same capstan, not only is the self-erection of
the crane obtained but also the operative positioning of the boom F
obtained, namely a position of the boom other than horizontal.
* * * * *