Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
lZ~7578
CART FOR LAYING GROUND COVERING ELEM~NTS
The present invention relates to a cart for layinq ground
covering elements. Ground covering elements to be laid
by means of the cart of the invention are especially slabs
that are too heavy for layinq by hand and qroups of paving
stones disposed adjacent one another that are grasped
and laid together as a group. The ground coverinq elements
or paving stones are preferably made of concrete and serve
for paving plazas, yards, driveways and the like.
It is the object of the invention to provide a cart for
layinq ground covering elements, which is simple in construction,
inexpensive and particularly sturdy.
To meet this ohject, the invention provides a cart for laying
ground covering elements which comprises the followin~
features:
(a) A movable frame which is equipped with front wheels,
at least one rear wheel and a backwardly extendinq
manlpulation boom;
(b) a forwardly projecting beam which is mounted to the frame
in a manner allowing a swivelling motion of said beam
about a horizontal swivel axis;
(c) a ground covering element gripper which is carried by
the beam;
(d) a mechanical spring means acting between the frame and
the beam and being designed such that it can swivel the
beam inthe upward direc-tion when the gripper does not carry
a ground covering element, and such that it allows a
swivelling motion of the beam in the downward direction,
with the spring means beinq increasingly loaded, when
the gripper carries a ground coverinq element.
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(e) and a mechanical brake means active between the frame
and the beam, the brake means being adapted to selectively
prevent and release the swivelling motion of the beam.
The wheels may be mounted to the frame in such a manner that
their direction of the axes relative to the frame is
determined. However, they may also be mounted to the frame
in such a manner that they are slewable relative to the
frame about a substantially vertical axis, for instance
in the manner of so-called trailing or caster wheels as
they are known from servina wagons or pushchairs. This
applies particularly to the rear wheel or wheels and results
in an easier maneuverability of the cart. The front and
rear wheels may be of different size, with smaller~rear wheels
being particularly feasible ~The mechanical spring means is
designed such that it may be loaded by the ground covering
element or ground covering element group having the lowest
weight for which the cart is intended, when the beam performs
a downward swivelling motion.
For the mechanical spring means, it is possible to use any kind
of conventional mechanical springs, for instance torsion sprinas,
spiral springs the windings of which are helically wound
on top of each other, conventional coil springs, spring members
made of rubber. However, use is preferably made of coil springs
under tension the one end of which is secured to the frame
and the other end of which biases the beam in the upward
swivelling direction. Particularly favorable assembly
conditions may be achieved when providing one curved guide means
as tension sprin~ support for each tension s~ring. referably, the guide means
has the sha~e of an arc of a circle and is concentric with the
swivel axis of the beam.
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Depending on the size of the swivel region of the beam
and on the size of the gro~lnd covering element gripper, it
may be advantageous to provide a beam with an angled course,
so that it will not be in the way of the gripper in the upper
swivel position of the beam.
A further development of the invention provides that the swivel
axis of the beam is located rearwardly of the axes of the
front wheels and forwardly of the axes of the rear wheels
or forwardly of the axis of the rear wheel. In this manner,
the load resulting from the weight of the covering element
hanging on the gripper is passed via the beam to the frame
at a fairly rear location, whereby a construction is achieved
which is compact and advantageous in terms of load. It
is particularly advantageous to design the beam such that it
can be swivelled in the upward direction at least to such an
extent that the gripper comes into the region located vertically
above the front wheels. Thus, when moving the cart the qripped
load is no longer in front of the front wheels, and it is no
longer necessary to balance the cart up by applying pressure on-
to the manipulation boom.
Preferably, the mechanical brake means has a brake spring which normally
keeps the brake means in the braking condition, so that, especially when -
moving the cart, the brake means need not be kept in the braking condition by
the operator. For eliminating the braking condition, there is provided an .
operatina mem~ which is in this case to be actuated by the operator. me
operating member may be designed for operation by hand or by foot and can
preferably be reached from the place where the operator normally stands, namely
at the end of the manipulation boom.
Preferably, the mechanical brake means is provided with a first
brake means member coaxially rotating with the beam and with a
second brake means member held at the frame, with the braking
condition being established by frictional engaqement between
said first and said second brake means member.
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Due to the arrangement of the first brake means member
coaxially Wit]l the swivel axis of the beam the compactness
of the cart is further enhanced.
~ particularly beneficial form
of the brake means consists in providing a band brake
which includes a brake wheel unrotationally connected to
the beam such that it is coaxial with the swivel axis of
the beam,and which includes a brake band wound round
the brake wheel and having one end secured to the frame
and the other end secured to an operating member the
position of which determines the extent to which the brake
band is pressed against the brake wheel. In relation
to the force required for establishing the braking condition,
this band brake provides a particularly high brakinq effect
and it is especially advantageous for maintenance.
It will become still clearer from the followinq description
that working with the cart of the invention in many cases
requires the frame as a whole to be swivelled about a
horizontal axis that is defined by the line of ground contact
of the front wheels or of the rear wheels. For the purpose
of facilitating these swivel motions of the frame, the frame
may be provided with a rearwardly extending extension having
a pedal to which the operator can apply a force with his foot.
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Ti1e invention will now be described in detail by way of an
embodiment shown in the drawing. The sole drawing fiqure
shows a side view of a cart with the
uppermost swivel position of the beam being shown in full
lines and the lowermost swivel vosition of the beam being
shown in broken lines.
The cart 2 depicted in the drawina comprises a frame 4
which is composed substantially of four supports. A irst
support 6 extends from the forward lower end of the frame 4
in an oblique direction upwardly to the upper rear. A second support 8
extends from the up2er end point of the first support 6 slightly
upwardly and to the rear and merges into a manipulation
boom 10. A third support 12 extends from the forward lower end
of the first supporL 6 in an oblique direction u~rdly and r~wardly, but
in a manner less steep than the first support 6. The rear
end of the third support 12 is connected to the second
support 12 via a fourth support 14 that extends upwardly in
a sl:eep manner. The rear end of the manipulation boom 10
is bifurcated and provided with two handles 16. Approximately
froM the point where the first support 6 is connected to
the second support 8, an additional support 18 extends
rearwardly and downwardly in an oblique direction; the
additional support 18 is connected to the third support 12
and to the fourth support 14 at the connecting point thereof
and extends rearwardly beyond this connecting point.
At the end of the additional support 18 there is provided
a pedal 20.
In the area of the connectin~ point between the first support 6
and the third support 12, there is provided a horizontal front
wheel axle 22 on which one pneumatic-tire front wheel 24 each
is rotatably mounted on the right side and on the left side
of the frame 4. A bracket 26 extends downwardly from the third
support 12 from the intermediate portion thereof and carries
a horizontal rear wheel axle 23. Tw~ re~r whee]s 30 with pneumatic tires
are rotatably mounted on the rear wheel axle 23, one wheel being
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mounted on the right side and the other wheel beinq mounted
on the left side of the frame 4. The wheels 24 and 30 rest,
~ith their lines of ground contact 32, on a surface 34 on
which the cart 2 can be moved by rolling movement of the
wheels 24 and 30.
Approximately in the middle of the length of the first support 6,
a beam 36 is mounted to the first support 6 in a manner
allowing a swivelling motion of said beam 36 about a horizontal
swivel axis 38. The beam 36 substantially has an inversely
L-shaped configuration, with the first leg 40 havingr when
the beam 36 is swivelled completely upwards, substantially
the same direction as the first support 6, said direction
extending obliquely and rearwardly upwards, and with the
second leg 42, which extends at right angles to the lower
leg 42, being, in this swivel position of the beam 36,
directed obliquely and forwardly upwards. The second
leg 42 has in its front portion a downwardly extending
bend. In the position in which the beam 36 is swivelled
completely downwards (drawn in broken lines), the first
leg 40 is directed obliquely and forwardly upwards and the second
leg 42 is directed o~liquely and forwardly downwards. me swivel axis 38
is located above the wheels 24, 30 and - as seen in the
longitudinal direction of the cart 2 - rearwardly of the
front wheel axle 22 and forwardly of the rear wheel axle 28.
A clamping gripper 42 is suspended at the forward, free
end of the beam 36 by means of a vertical rod 40.
The upper end of the rod 40 is hingedly connected to the
beam 36 and the lower end of the rod 40 is hingedly connected
to the clamping gripper 42. The clamping gripper 42 comprises
two gripper jaws 44 and 46 which are pivotable relative
to each other and which are adapted to close automatically
when the clamping gripper 42 is being lifted.
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Coaxially with the swivel axis 38, two guide means 48
curved in the manner of an arc of a circle are unrotationally
connected to the beam 36, namely one guide means 48
laterally on the left side of the beam 36 and the other guide
means 48 laterally on the right side of the beam 36.
One tension spring 50 each, which is designed as a coil spring,
is anchored with its upper end to an associated one of the
two guide means 48 and with its lower end to the frame 4
in the region of the front wheel axle 22. When swivelling
the beam 36 in the downward direction, each of the two tension
springs 48 is thus stretched and the rearward upper portion
thereof is increasingly supported on the associated guide
means 48 in an arcuate manner. In this manner, tension
springs 50 having a long stroke can be used and accommodated
in a space-saving manner.
On one side of the beam 36, a brake wheel 52 is
unrotationally connected to the beam 36 such that it is
coaxial with the swivel axis 38. The brake wheel 52 is
located axially adjacent one of the guide means 48. The
outer circumference of the brake wheel 52 is of circular
shape. A brake band 54 having an inner brake lining 56
is wound about the outer circumference of the brake wheel 52
to an extent of approximately 270. An operating member
in the form of a foot lever 58 is hingedly connected to
the additional support 18 approximately in the middle thereof
in such a manner that it is pivotable about a joint or link 60.
One end of the brake band 54 is secured to the frame 4 in
the region of the joint 60. The brake band 54 extends from
the joint 60 approximately in the direction of the
additional support 18 and to the outer circumference of the
brake wheel 52. After encircling the brake wheel 52 at
an angle of approximately 270, the brake band 54 extends
obliquely and rearwardly upwards to a mounting point 54 at
the foot lever 58, with a drawbolt 62 being interposed
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therebetween, with the mounting point 64 being spaced
from the joint 60 by several centimeters towards the rearward
lower end of the foo~ lever 58. A coil spring 66 under tension
extends between the foot lever 58 and the second support 8
and it normally pulls the footlever 58 upwards with a force
of such great extent that the hrake band 54 is pulled
against the brake wheel 52 in such a strona manner that the
beam 36 is prevented from swivelling in the downward direction
even when the clamping gripper 42 is loaded. When the operator
presses the foot lever 58 with his foot downwardly against
the action of the spring 66, the brake band 54 is loosened
and the beam 36 may perform a swivelling motion.
The construction of the embodiment shown in the drawina is
such that the beam 36 consists of two steel profiles which
are arranged in parallel, connected to each other by means
of transverse braces (not shown) and which are disposed
on the right and on the left of (in the drawing in front of and
behind) the first support 6, so that the frame 4 is located,
so to speak, between the two steel profiles of the beam 36.
As an alternative thereto,the frame 4 may be composed of
supports 6, 8, 12, 14 which each consist of steel profiles-which
are arranged in parallel to each other on the right and on the left (in
the drawing in the front and in the rear~, and the beam
may be disposed between the steel profiles of the first
support 6. In this case, the beam 36 may consist of one
single steel profile.
For adaption to ground covering e]ements or ground covering
element ~roups of differing size or differing wei~ht that
are to be laid, it is possible to make the manipulation
boom 10 and/or the first leg 40 of the beam 36 and/or the
second leg 42 of the beam 36 and/or the support 18 leading
to the pedal and/or the foot lever 58 adjustable in length,
for instance by the possibility of telescopic lengthening
or shorteninq.
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Working with the cart of the invention can be performed
in the following manner:
The coverinq elements, for instance groups of interlockin~ stones
of concrete, are provided in layers in the form of a supply
stack resting on the ground 34. The operator moves the cart 2
to the supply stack, with the clamping gripper 42 being
raised to the required height, and lowers the clamping qripper 42
to the uppermost layer of the supply stack by swivelling the
cart 2 in total about a line 32 of qround contact. In doing
so, the clamping gripper 42 comes into the region in front of
the front wheels 24, since the upper point of pivot of the rod 40
is shifted forwardly and since the rod 40 always adjusts
to a vertical position. When the touch or contact lever 68 of the
clamping gripper 42 comes into contact with the upper surface
of the uppermost ground covering element layer which is to
be gripped, the gripper jaws 44 and 66 extending transversely
of the longitudinal direction of the cart 2 are unlocked
and come into engagement with two opposed sides of the ground
covering element layer to be gripped. When subsequently raising
the clamping gripper 42 by swivelling the cart 2 about a line 32 of ground
contact, which is assisted by the operator applying force with his foot
to the pedal 20, the gripper jaws 44 and 46 close automatically so that the
ground CO~Jering element group to be laid is lifted off from the supply stack
~nd suspended from the beam 36 while being held together by the clamping effect
of the clamping gripner 42. me band brake is applied during the whole of this
operation. Due to the backward swivelling motion of the cart 2 about a line 32
of ground contact, the clampin~ gripper 42 and, thus, the aripped ground
covering element group comes into the region vertically above the fror,t
~eels 24, so that the cart stands balanced in itself and does not have to be
stabilized by applying force to the pedal 20 or to the handles 16. ~en,
the operator moves the cart 2 to the desired laying site
of the gripped ground covering element group. After having
arrived there, the operator releases the band brake by
applying pressure with his foot to the brake release-lever 58,
and the beam 36 s~ivels in the downward direction until the
ground covering element group is placed down at the intended site.
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The tension sprinqs 50 become tensioned during this swivelling
motion of the beam 36 in the downward direction. Due to the
touchinq down of the ground covering element aroup at the laying
site and, if necessary, in addition bv sliqhtly swivellina
the cart 2 about a line 32 of ~round contact, the clamping gripper 42
is released and locked in the spread apart, opened position, so that the
clarnping gripper 42 may be raised subsequently without lifting the laid ground
covering element group again. The subsequent swivelling
of the beam 36 in the upward direction is effected by the
tensioned tension springs 50 which are adapted to raise
the beam 36 and the unloaded clamping gripper 42. For doing
so, the operator releases the band brake by applying pressure
with his foot to the brake release lever 58. Thereafter,
a new laying cycle can commence.
