GB1566541A

GB1566541A - Transporting and laying apparatus

Info

Publication number: GB1566541A
Application number: GB6436/78A
Authority: GB
Original assignee: ALLG STRASSENBAUBEDARFS GmbH
Current assignee: ALLG STRASSENBAUBEDARFS GmbH
Priority date: 1977-02-22
Filing date: 1978-02-17
Publication date: 1980-05-08
Also published as: ZA781048B; FR2381133A1; DE2707495A1; NL7801817A; SE7801685L; CA1090742A; DK78278A; CH629864A5; FR2381133B3; SE421119C; SE421119B; DE2707495B2

Abstract

The frame (10) of the device is manually movable on rollers (14, 15); it has a rigid arm (21), the free end of which bears a gripper (30) for gripping stone slabs or the like. The gripper (30) is only movable vertically, in particular by linear displacement of the arm (21) along the vertical T-supports (12) of the frame (10). An energy accumulator (41) accumulates, on the lowering of the loaded gripper (30) which is controlled with the aid of a brake (60), the energy thus released, which guides the empty gripper (30) back into its raised position again. The device is thus permitted a perfect lowering movement during positioning of plate-shaped road surfacings. <IMAGE>

Description

(54) TRANSPORTING AND LAYING APPARATUS (71) We, ALLGEMEINE STRASSENBAUBE DARES-GES. M.B.H., a German Company, of Lesumer Heerstrasse 42, 2820 Bremen 77, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The invention relates to apparatus for transporting and laying substantially slablike road-surfacing elements.

Usually, slab-like road-surfacing elements are laid on to a bed of sand which has previously been made level, while maintaining the joints in relation to adjacent elements as uniform as possible.

Known laying apparatus for transporting and laying slab-like road surfacing elements has comprised a wheel-mounted frame carrying a rocking arm from which is suspended tongs for gripping a surface element or elements. Since it has been recognised that the road-surfacing elements should be lowered to their required positions as far as possible vertiCally, so that more uniform joints may be established and impacts with slabs which have already been laid are avoided, care has been taken to have the pivot point of the rocking arm as far as possible away from the tongs. As a result, the lowering operation takes place with a relatively large swinging radius.

However, it has been found in practice that even an enlarged swinging radius does not permit neat, vertical laying movement of the elements and consequently accurate positioning of the slabs is not generally possible.

It is an object of the invention to provide transporting and laying apparatus, which permits a satisfactory vertical lowering movement with the positioning of slab-like road surfacing elements and the like.

Apparatus .for..transporting and. laying road surfacing elements of substantially slab-like form comprises, according to the frame capable of limited tilting movement about one axis of the wheels or rollers; an outwardly extending cantilever arm and a handle mounted on the frame at opposite ends thereof; lifting and lowering tongs for gripping the surfacing element, which tongs are carried by the cantilever arm and are arranged to be guided linearly and moved substantially vertically relative to the frame; and an energy-storage device arranged to act against the weight of the elements to store energy during lowering of the tongs under the effect of gravity from an elevated position and to cause return of the unloaded tongs back to the elevated position under control of a control device on the handle.

It is by these means that, for the first time, a working principle which has long been considered to be desirable is achieved.

The operator is now able accurately to position the apparatus with the slab which is carried by the latter and deposit it exactly at the prescribed position. This provides accurate joints and a clean laying of the slabs, both as regards the lateral spacings of tbe slabs and also horizontal alignment.

Several possibilities are offered as regards carrying out in practice the solution provided by the invention. In one constructional example which is explained in the following description, the cantilever arm is guided in a linear guideway and the tongs. are directly arranged on the free end thereof. As an alternative thereto, however, the tongs may be suspended by means of a cable from a rigid cantilever arm and, for example, the other end of the cable may be connected to a spring constituting the energy-storing device; the cable may pass over intermediate pulleys. Again, scissor-like parallelogram linkage may connect the cantilever arm and the tongs suspended there beneath; the energy-storing device may then be in tbe form of a spring connected between the free hinge points of the linkage.

In the preferred constructional form, a traction cable may be connected at one end to the vertically movable cantilever arm and at the other end to the frame and guided over a displaceably mounted pulley, which is coupled to the energy-storing device. In this case, the mounting of the pulley may guide the latter in the direction of the linear guideway.

The exchange of energy between the energy-storing device and the tongs may, for example, be effected by way of a hydraulic transmission with a pair of hydraulic cylinders, which are in communication with one another. One of the hydraulic cylinders may be combined with the dis nlaceable guiding means of the pulley and the oihe r hydraulic cylinder may be combined w th the energy-storage device.

For retarding the movements which occur with exchange of energy between the tongs and the energy-storage device, a brake which is controlled by the control member may advantageously be employed.

3y way of example, this brake may be a erection brake, which is operative on a brake disc driven from the guide means of he pulley. As an alternative, the brake inlay also be formed as a throttle device in he connecting pipe between the two hy raulic cylinders.

It is possible to employ self-clamping tongs of a design as known per se, in which he two clamping jaws are fixed on the tower ends of intersecting arms of the 1onus; the said arms are mounted to be rotatable about a common pivot at the point of intersection. The upper end of the arms of the tongs is pivotally connected to he cantilever arm.

According to another particularly preerred constructional form of the invention, tongs are used of which the two vamping jaws are each arranged on the bottom end of tong arms which intersect freely and which are rotatably mounted below the point of intersection, each about i1s own pivot axis, the pivots extending parallel to one another. In this constructional form, the upper ends of the tong arms are likewise so pivotally connected to the cantilever arm that the clamping jaws, by a rotational movement about their own pivots which are separate from one another, are moved towards one another and clamp the element which is to be laid.

Preferably, the two pivots are positioned relatively to one another with a spacing which is prescribed by the shape of the element to be laid and by at least one connecting rod. For increasing the clamping pressure, the pivots by which the connecting rod and the arms of the tongs are pivotally connected to one another are disposed near the clamping jaws of the tongs. As a result, the distance covered by the clamping jaws for tightly clamping the element to be laid is reduced and the clamping forces which become operative with this reduced travel is increased. The clamping action can thereby be so greatly increased that it is possible to pick up safely and reliably composite slabs consisting of a number of individual blocks which are interlocked.Such composite slabs are usually manufactured in integral form with the individual blocks secured temporarily together by readily broken webs, in order to facilitate their transport and laying, those webs being ruptured after laying; it may happen that the composite blocks during transport may become broken into individual blocks or sets of blocks when it becomes necessary to lay the blocks by hand. By the use of the tongs of the invention, it is not only possible to handle and lay an unbroken composite block, but also a composite block which has become separated into individual blocks or sets of blocks.

The invention will be more readily understood by way of example from the following description of a slab transporting and laying device in accordance therewith, reference being made to the accompanying drawings, in which Figures 1 and 2 show the device in side view and in plan respectively, Figure 1 being partly in section, Figure 3 is a perspective view on larger scale of part of the device of Figures 1 and 2 and illustrates the brake, and Figures 4 and 5 are respectively a side view and a plan view of a particular constructional form of the tongs.

The transporting and laying device illustrated in the drawings comprises a vertical frame 10 consisting essentially of two Tsection girders 12 which are fixed vertically on a base plate 13 and which are braced to one another in suitable manner. The frame 10 can be tilted at the front end about the axis of a pair of wheels 14 arranged on the base plate and is additionally supported towards the rear end by a caster 15. Disposed at a distance behind the rear caster 15 which permits the manipulation of the device are handles 16, which are rigidly connected by upper and lower pairs of struts 18 to the frame 10.

Self-clamping tongs 30 of conventional design serve for the gripping and laying of the paving elements which are to be laid and which are in the form of heavy stone slabs or the like. Tongs 30 are suspended from a beam 20 projecting forwardly from the frame 10 as a cantilever arm and are displaceable together with the beam 20 in a linear guideway 26 longitudinally of the frame 10. The beam 20 consists essentially of a horizontally extending arm 21 and a substantially vertically extending guiding section 22, which has at least one roller 24 at the top and bottom ends in the vicinity of each of the two T-section girders 12.

In the present constructional example, the guiding section 22 of the arm 20 has in all four of these rollers 24, of which there are two on each side, and which are guided in the U-section rails of the linear guideway 26 (see Figure 2). Obviously, the linear guideway for the beam 20 may have a form different from that illustrated, and may for example comprise ball bearings, ball guideways, sliding tracks or the like.

The entire beam 20 is suspended from a traction cable 33; this cable is connected by means of an eye 35 to the base of the arm 21 of the beam 20, is guided upwardly over a freely rotatable roller 32 in the form of a cable pulley and is fixed at its opposite end to an eye 34 forming part of the base plate 13. A bearing block which carries the spindle of the pulley 32 is connected to the closed end of a vertically disposed long-stroke hydraulic cylinder 44 which is displaceable longitudinally of the frame 10 on a piston rod 49. Piston rod 49 is drilled longitudinally to form a flow duct and is fixed by means of a stable base plate to the base plate 13 of the frame 10.The long-stroke cylinder 44 is thus connected to the beam 20 by a transmission consisting of the traction cable 33 and the pulley 32 in such a manner that the vertical displacement of the beam 20 through a distance s is effected by a displacement of s/2 of the longstroke cylinder 44 in relation to the stationary piston rod 49.

The internal chamber of the long-stroke cylinder 44 is constantly in communication with the internal volume of a hydraulic short-stroke cylinder 43 through a hydraulic pipe 50 and the longitudinal bore of piston rod 49, and the two chambers and communicating pipes are completely filled with hydraulic liquid. The cylinder 43 is supported at the rear of the device by the stays 18 and, in conjunction with a compression spring 41, forms an energy-storage device 40. The compression spring is clamped between a movable plate 46 fixed on a piston rod 45 of the short-stroke cylinder 43 and a fixed plate 47 connected by stay bolts to the short-stroke cylinder in such a way that it is urged to force the piston of the short-stroke cylinder 43 with its piston rod 45 into the retracted end position as shown in Figure 1.In this retracted end position, the short-stroke cylinder 43 is substantially emptied and the hydraulically connected long-stroke cylinder 44 is positively forced out into its upper end position. In this normal position of the apparatus, the beam 20 with its tongs 30 assumes the upper end position as shown in Figure 1.

The energy storage device 40, which is shown in Figures 1 and 2 as a compression spring, may alternatively consist of a gas accumulator; for example the cylinder 43, extended in length if necessary, may contain a flexible diaphragm above which is contained a trapped volume of gas.

Associated with the beam 20 is a brake 60, which holds the beam in a rest position thereof at any required position along the linear guideway 26. As may best be seen from Figure 3, the brake 60 includes a brake disc 62 which normally is clamped between a fixed brake plate 67 and a movable brake plate 68, the brake disc 62 having fixed thereon a pinion 63 constantly in mesh with a rack 65, which is connected fast to the guiding section 22 of the beam 20. In the same way as the shaft for the brake disc 62, the T-section girder 12 has fixed thereon a L-shaped brake support 77 carrying a pin-like fulcrum 70, about which is rotatably mounted a brake lever 69 supporting the movable brake plate 68.This brake lever 69 is constantly pre-tensioned by a pressure-applying spring 72 with a force which is adjustable by means of a tensioning device 73 in such a way that the movable brake plate 68 damps the brake disc 62 between it and the fixed brake plate 67 with an adequate braking force.

As shown in Figure 2, a control device 79 in the form of a brake lever is arranged close to one of the two handles 16, and it is possible by means of the said member 79 to release the brake 60 as required by means of a Bowden cable 75. As shown in Figure 3, the sheath of the cable 75 is connected to the brake support 77 and the internal cable thereof is connected to the bottom end of the brake lever 69.

The tongs of conventional type, as shown in Figures 1 and 2, have two clamping jaws 80 on the bottom end of two intersecting arms 82, which are rotatably mounted at their point of intersection on a common pivot 84.

Figure 4 and 5 represent a particularly preferred alternative construction of the tongs, in which the two clamping jaws 80 are fixed on the bottom ends of two intersecting arms 82 of the tongs. By contrast with the tongs of known type, the two arms 82 do not have a common pivot at the point of intersection. In actual fact, each arm 82 is mounted to be rotatable about its own pivot axis, which, in the embodiment shown, comprises a pair of pivots 86 and 88, respectively. The pivots 86, 88 extend parallel to one another at opposite ends of a pair of connecting rods 90. The upper ends of the arms 82 are connected to the cantilever arm 20 by means of pivotally arranged links 83 so that the arms 82 of the tongs and thus the clamping jaws 80 rotate about the pivots 86, 88 when the cantilever arm 20 is raised.As a result, the clamping jaws 80, because of their small spacing from the pivots 86 and 88, travel a relatively small distance in the direction towards the elements to be laid. On account of the correspondingly large lever transmission, relatively large clamping forces become operative. The two pivots 86, 88 are positioned at a distance from one another which is prescribed by the dimensions of the elements to be laid. Apart from the pivots 86 and 88, the connecting rods 90 do not have any other mounting or fixing means.

The clamping jaws can be shaped to correspond to the contour of the elements to be laid and can be provided, at least in certain positions, with resilient coverings 85. The clamping force can also be transmitted through possibly adjustable pressureapplying rollers 81 or the like.

In operation, the transporting and laying device is advanced by an operator to a stack of slabs, and then, by tilting the apparatus forwards about the axis of wheels 14, the tongs are moved towards the uppermost slab of the stack of elements to be laid. When the apparatus is tilted back, the clamping jaws of the tongs 30 grip the slab and, since these jaws are selflocking, the slab is lifted. The operator now moves the apparatus with the slab to the laying site, releases the brake 60 by means of the control member 79, so that the weight of the slab depending from the beam 20 is able to overcome the force of the compression spring 41 and the beam 20 moves downwardly at a speed which possibly is adjustable by means of a hydraulic throttling device. Just before the slab has reached the ground, the operator once again allows the brake 60 to engage.

He now so aligns the complete device that the slab hanging on the tongs 30 is exactly located above the position at which it is to be fitted. He then once again releases the brake until the slab makes contact with the ground. After once again engaging the brake, the operator briefly tilts the apparatus in a forward direction, so that the tongs 30 are released. A new working cycle can then commence.

The tongs 30 are shown at Figures 4 and 5 as holding a composite slab 94 consisting of interlocking stone blocks.

WHAT WE CLAIM IS: 1. Apparatus for transporting and laying road surfacing elements of substantially slab-like form, the apparatus comprising a wheel- or roller-mounted frame capable of limited tilting movement about one axis of the wheels or rollers; an outwardly extending cantilever arm and a handle mounted on the frame at opposite ends thereof; lifting and lowering tongs for grip ping the surfacing elements, which tongs are carried by the cantilever arm and are arranged to be guided linearly and moved substantially vertically relative to the frame; and an energy-storage device arranged to act against the weight of the elements to store energy during lowering of the tongs under the effect of gravity from an elevated position and to cause return of the unloaded tongs back to the elevated position under control of a control device on the handle.

2. Apparatus according to claim 1, in which the cantilever arm is movably guided in a linear guideway on the frame and the tongs are carried directly on the free end of the arm, the substantially vertical movement of the tongs being effected by movement of the arm.

3. Apparatus according to claim 2, in which a traction cable is connected at one end to the cantilever arm and at the other end to the frame and is guided over a displaceably mounted freely rotatable pulley, which is coupled to the energy-storage device for the purpose of raising the cantilever arm.

4. Apparatus according to claim 3, in which the pulley is guided for movement in the direction of linear guideway.

5. Apparatus according to any one of the preceding claims, in which the energystorage device is coupled to the tongs through a hydraulic transmission incorporating a pair of hydraulic cylinders.

6. Apparatus according to claims 3 or 4, in which the pulley is mounted on a hydraulic piston and cylinder unit which is hydraulically coupled to a second hydraulic piston and cylinder unit combined with the energy-storage device.

7. Apparatus according to any one of the preceding claims in which a brake controlled by the control device is provided for retarding the movement of the tongs under the action of the energy-storage device.

8. Apparatus according to claim 3 and claim 7, in which the brake is a friction brake, which is operative on a brake disc driven by the movement of the pulley.

9, Apparatus according to claim 3 and claim 7, in which the brake is a throttling device between the hydraulic cylinders.

10. Apparatus according to any one of

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. own pivot axis, which, in the embodiment shown, comprises a pair of pivots 86 and 88, respectively. The pivots 86, 88 extend parallel to one another at opposite ends of a pair of connecting rods 90. The upper ends of the arms 82 are connected to the cantilever arm 20 by means of pivotally arranged links 83 so that the arms 82 of the tongs and thus the clamping jaws 80 rotate about the pivots 86, 88 when the cantilever arm 20 is raised. As a result, the clamping jaws 80, because of their small spacing from the pivots 86 and 88, travel a relatively small distance in the direction towards the elements to be laid. On account of the correspondingly large lever transmission, relatively large clamping forces become operative.The two pivots 86, 88 are positioned at a distance from one another which is prescribed by the dimensions of the elements to be laid. Apart from the pivots 86 and 88, the connecting rods 90 do not have any other mounting or fixing means. The clamping jaws can be shaped to correspond to the contour of the elements to be laid and can be provided, at least in certain positions, with resilient coverings 85. The clamping force can also be transmitted through possibly adjustable pressureapplying rollers 81 or the like. In operation, the transporting and laying device is advanced by an operator to a stack of slabs, and then, by tilting the apparatus forwards about the axis of wheels 14, the tongs are moved towards the uppermost slab of the stack of elements to be laid. When the apparatus is tilted back, the clamping jaws of the tongs 30 grip the slab and, since these jaws are selflocking, the slab is lifted. The operator now moves the apparatus with the slab to the laying site, releases the brake 60 by means of the control member 79, so that the weight of the slab depending from the beam 20 is able to overcome the force of the compression spring 41 and the beam 20 moves downwardly at a speed which possibly is adjustable by means of a hydraulic throttling device. Just before the slab has reached the ground, the operator once again allows the brake 60 to engage. He now so aligns the complete device that the slab hanging on the tongs 30 is exactly located above the position at which it is to be fitted. He then once again releases the brake until the slab makes contact with the ground. After once again engaging the brake, the operator briefly tilts the apparatus in a forward direction, so that the tongs 30 are released. A new working cycle can then commence. The tongs 30 are shown at Figures 4 and 5 as holding a composite slab 94 consisting of interlocking stone blocks. WHAT WE CLAIM IS:

1. Apparatus for transporting and laying road surfacing elements of substantially slab-like form, the apparatus comprising a wheel- or roller-mounted frame capable of limited tilting movement about one axis of the wheels or rollers; an outwardly extending cantilever arm and a handle mounted on the frame at opposite ends thereof; lifting and lowering tongs for grip ping the surfacing elements, which tongs are carried by the cantilever arm and are arranged to be guided linearly and moved substantially vertically relative to the frame; and an energy-storage device arranged to act against the weight of the elements to store energy during lowering of the tongs under the effect of gravity from an elevated position and to cause return of the unloaded tongs back to the elevated position under control of a control device on the handle.

10. Apparatus according to any one of

claims 1 to 9, in which the tongs have two clamping jaws located at the bottom end of intersecting tong arms, which are mounted to be rotatable about a common pivot at the point of intersection, and of which the upper ends are pivotally connected to the cantilever arm.

11. Apparatus according to any one of claims 1 to 9, in which the tongs have two clamping jaws which are located at the bottom end of freely intersecting arms and which are pivotally mounted about individual pivots which extend parallel to one another, the upper ends of the tong arms being pivotally connected by means of links to the cantilever arm.

12. Apparatus according to claim 11, in which the two pivots are positioned relatively to one another at a distance from one another prescribed by the shape of the elements to be laid and determined by connecting rods.

13. Apparatus according to claim 11 or claim 12, in which the pivots are arranged close to the clamping jaws of the tongs.

14. Apparatus for transporting and laying road surfacing elements, substantially as herein described with reference to the accompanying drawings.