[0001] The invention relates to an apparatus for displacing a load, comprising a platform
with a telescopic boom movable in the vertical plane, means mounted on the free end
of the boom for removably arranging attachments such as lift forks, a winch supported
by the platform for a hoisting cable guided along the boom and having a hook for the
load.
[0002] Such an apparatus is normally used for earth-moving purposes or load displacement,
for which purpose the telescopic arm is provided with an exchangeable attachment.
Such a vehicle is also known in the field as a "telescopic handler". This machine
is provided for this purpose with a number of suitable attachments, for instance an
excavator or gripping device, forks for use with pallets, and a tackle for hoisting
purposes. A lift platform can further be arranged for lifting workers such as painters
and the like.
[0003] The invention has for its object to modify the apparatus of the type stated in the
preamble such that it can operate better as hoisting apparatus.
[0004] To this end the apparatus is distinguished according to the invention in that a jib
provided with a fixed top pulley for the cable is pivotally mounted on the free end
of the boom, wherein the length of the jib is such that, as seen in the vertical plane,
for all positions of the boom the vertical line along the top pulley runs clear of
these mounting means on the boom.
[0005] Owing to the use of the jib it is possible to obtain a greater range, which is however
possible up to a determined angular position of the boom relative to the horizontal.
[0006] Owing to the pivot, the jib can be folded relative to the boom, whereby the telescopic
handler can operate up to a maximum height.
[0007] The invention further relates to an apparatus for displacing a load, comprising a
platform with a telescopic boom movable in the vertical plane, a winch supported by
the platform for a hoisting cable guided along the boom and having a hook for the
load.
[0008] Such an apparatus, which can be a random crane with telescopic mast, is distinguished
according to the invention in that a jib provided with a fixed top pulley for the
cable is pivotally mounted on the free end of the boom, wherein the length of the
jib is such that, as seen in the vertical plane, for all positions of the boom the
vertical line along the top pulley runs clear of these mounting means on the boom.
[0009] The advantage of this embodiment is that when the telescopic boom is extended, i.e.
when the sections of the boom slide apart, the hoisting cable co-displaces synchronously
so that the crane operator need only concentrate on the load for hoisting, which retains
the same height in a determined angular position during lengthening or shortening
of the boom. Above mentioned and other features of the invention are elucidated in
the figure description hereinbelow of two embodiments.
[0010] In the drawing:
Fig. 1 shows a perspective view of a mobile platform in the position of use;
Fig. 2 shows a detail of the top of the boom applied in the apparatus of figure 1;
Fig. 3 shows a detail corresponding with figure 2 of the top of the boom with folded
jib applied in the apparatus of figure 1;
Fig. 4 shows the position of the jib in use of the telescopic handler with other attachments;
Fig. 5 shows a schematic view of the synchronous control in a telescopic boom and
the hoisting cable.
[0011] Designated in figure 1 with the numeral 1 is the mobile platform which can be manufactured
in random manner. At the four corner points the mobile platform 1 is embodied with
outriggers 2 which can be retracted and extended in known manner to enable stable
arrangement of the platform in the situation of use. On platform 1 is arranged a turret
3 which is embodied here with a telescopic arm 4 in the form of four pipe sections
slidable into each other.
[0012] On the free end of telescopic arm 4, i.e. the end remote from pivot shaft 5, is arranged
a coupling member 7 which in the normal course of events is used for coupling of random
attachments, for instance forks for pallet use, excavators for excavation purposes
and other types of attachment.
[0013] Mounted according to the invention on the upper end of the boom is a jib 8 which
is further elucidated hereinbelow with reference to figures 2 and 3. This jib is particularly
intended for lengthening boom 4 such that the boom with jib 8 can form one long boom
for a hoisting attachment, this such that a hoisting cable 9 can be trained along
the boom and jib 8 via guides. Cable 9 is wound or unwound round a driven drum 10
and is provided on the free end with a hook 11 for a load L.
[0014] Figure 2 shows a detail of jib 8 which is mounted pivotally on the end of telescopic
boom 4. In the position according to figure 2, the jib 8 is in line with boom 4 and
cable 9 runs round a top pulley 12 which is received for free rotation on a shaft
13 between mounting plates 14.
[0015] At the pivot shaft 15, which is also the rotation shaft of a second cable pulley
16, jib 8 with two support plates 17 is rotatable relative to the boom end.
[0016] In the position of figure 3 the jib is folded down relative to boom 4, which can
be performed manually by the operator if the boom is retracted and swivelled downward,
wherein the locking positions can be achieved using known pin-hole connections.
[0017] The difference between operation in the position in figure 2 respectively 3 is that
the boom in the position according to figure 2 can reach an angle of inclination of
α1 with the horizontal, but in figure 3 of α2, which is greater than α1. This is possible
because, due to the folded-down position, the vertical line along the outside of top
pulley 12 always runs along the mounting means 7 for the other attachments.
[0018] Owing to this construction it is possible either to obtain a greater range in the
lengthened position according to figure 2 or to reach a maximum height in the position
according to figure 3.
[0019] In figure 4 can be seen that the jib is also provided with a second pivot shaft 20
which extends perpendicularly of said first pivot shaft 15. Jib 8 can hereby be folded
along boom 4, whereby the telescopic arm 4 with mounting means 7 for the other attachments
becomes freely accessible.
[0020] Figure 5 shows a schematic diagram, wherein the sections of boom 4 are monitored
by a roller 25 along which a magnet sensor 26 detects the rotation, i.e. the distance
covered by the sections relative to the other section. The generated signal from the
magnet sensor is fed to an electronic circuit 27, which also receives information
from a second magnet sensor 28 co-acting with a roller 29 which rolls against movable
hoisting cable 9.
[0021] During lengthening respectively shortening of boom 4 the sections will move in or
out of each other as according to arrow P1. This movement is detected by sensor 25,
26, while simultaneously the motor of the winch drum is actuated, wherein the displacement
of hoisting cable 9 is measured by sensor 28, 29. Both the signals generated by magnet
sensors 26, 28 are compared in comparing circuit 27, which then adjusts the motor
of winch drum 10 in the case of differences.
[0022] With this embodiment the operator is not distracted and can concentrate fully on
the load.
[0023] It is possible within the scope of the invention to apply such a compensation system
as according to figure 5 on any random crane with telescopic arm. It can of course
also be applied to the above described telescopic handler as shown in the drawings.
The invention is not limited to the above described embodiment.
1. Apparatus for displacing a load, comprising a platform with a telescopic boom movable
in the vertical plane, means mounted on the free end of the boom for removably arranging
attachments such as lift forks, a winch supported by the platform for a hoisting cable
guided along the boom and having a hook for the load, characterized in that a jib provided with a fixed top pulley for the cable is pivotally mounted on the
free end of the boom, wherein the length of the jib is such that, as seen in the vertical
plane, for all positions of the boom the vertical line along the top pulley runs clear
of these mounting means on the boom.
2. Apparatus as claimed in claim 1, characterized in that a second cable pulley is arranged close to the pivot between the jib and the boom.
3. Apparatus as claimed in claim 1 or 2, characterized in that the pivot line between the jib and the boom lies through the axis of rotation of
the second cable pulley.
4. Apparatus as claimed in any of the foregoing claims, characterized in that a second pivot shaft is arranged perpendicularly of the first shaft between boom
and jib.
5. Apparatus for displacing a load, comprising a platform with a telescopic boom movable
in the vertical plane, a winch supported by the platform for a hoisting cable guided
along the boom and having a hook for the load, characterized in that a switching circuit is arranged for actuating the winch motor synchronously with
the motor for the telescopic boom.
6. Apparatus as claimed in claim 5, characterized in that the switching circuit is provided with a displacement sensor for a boom section and
a displacement sensor for the hoisting cable, wherein a comparing circuit fed by signals
from the sensors actuates the winch motor in the case of difference.
7. Apparatus as claimed in any of the foregoing claims 1-4, provided with a synchronous
control of the winch motor with that of the telescopic boom as claimed in either of
the claims 5 or 6.