The present invention relates to a device at tear down demolishers, concrete and scrap demolishers, which in a starting position are pivotally mounted in their length direction on tool carriers, mainly excavators, in order to make it possible to manoeuver, such as to grip and demolish material, by connection to the hydraulic system of the tool carrier.

When previously performing demolishing work, diffe¬ rent types of concrete crushing equipment have been used, such as air driven hammers mounted on tool carriers men¬ tioned above. However, air hammers have become more and more troublesome to use during later years due to the heavy noise generated at the use of tools of this kind. As a con¬ sequence demolishing tools of the above mentioned kind have more recently been used to an increasing extent.

Such demolishing tools, though having a pivoting pos- sibility, are always to be seen as accessory equipment for tool carriers, such as excavators, and is often supplied from manufacturers that have only adapted the fastener of its demolishing equipment to the tool holder of the tool carrier. As a consequence of insufficient constructional adaptation, problems both with regard to durability and to stability will arise, which problems may have immediate consequences both in break downs and in the long run due to that the details of the tool carrier are subjected to loads which they are not dimensioned for. When a demolisher equipment of the above mentioned kind pinches an object which is not in line with the arm of the tool carrier, special problems will arise. Hereby large bending moments are applied on the tool carrier, which even may be dangerous when the force of the demolisher gives a torque in the transverse direction of the tool carrier, in

which direction the stability of the tool carrier does not limit the forces on the equipment.

The object of the present invention is to provide an equipment with which the problems described above and asso- ciated therewith are solved.

According to the invention the demolisher is comple¬ tely self-adjusting as a consequence of that the hydraulic force necessary to manoeuver the legs of the demolisher, pivotally journalled in a bracket, emanates from a coupling between the legs of the demolisher at the same time as the legs of the demolisher together with the pressure cylin¬ der/cylinders acting on these are journalled in at least one common attachment point in the bracket.

The invention will be further described below under reference to the attached drawings, which show and eluci¬ date the problem in question as well as describe an embodi¬ ment of the invention, and in which:

Fig. 1 is a side view of a known concrete demolisher construction, which through its construction gives both torque and bending moment on the tool carrier,

Fig. 2 is another side view of a known concrete de¬ molisher, having a pivotal connection between the tool carrier and the demolisher in order to eliminate the reac¬ tion force from the torque, Fig. 3 is a top view schematically showing an excava¬ tor as a tool carrier and the action from the bending moment which appears as a consequence of the grip of the demolisher,

Fig. 4 is a view corresponding to Fig. 3, though with a demolisher according to the invention,

Fig. 5 more in detail shows the construction of and the mobility of a demolisher according to the invention,

Fig. 6 shows further details of preferred embodiments of the invention, and

Fig. 7 shows an alternative embodiment of a demo¬ lisher according to the invention.

Fig. 1 shows how a demolisher of a known kind works. One of the legs 1 of the demolisher, which at the same time constitutes a foundation for attachment to a tool carrier 2, is made to grip around an object in that another leg 3 is pivoted around a pivot point on the leg 1 and is actua¬ ted by a hydraulic cylinder operating from the foundation. With a construction of this kind both a bending moment and a torque from the demolisher are obtained and are directly transferred to the tool carrier 2 with the resulting pro¬ blem recited above.

Fig. 2 shows a construction which prevents the appea¬ rance of a torque when gripping and/or cutting an object. This is obtained in that both the legs 1 and 3 are mounted on a carrier 4, which in turn is pivotably arranged on a mounting bracket, which in its turn is fastened to the tool carrier 2 in a conventional manner (not shown) . Fig. 3 is only intended to show (somewhat exaggerated) how a demo- lisher construction according to Fig. 2 effects the tool carrier 2 when a bending moment arises.

Fig. 4 schematically shows an embodiment of the in¬ vention and how such a demolisher trough its self-adjusting function uses said bending moment for turning the legs of the demolisher until an equilibrium at a bending moment which approximately is equal to zero arises.

The demolisher according to Fig. 4 is shown more in detail in Fig. 5 where it is more evident how the legs of the demolisher are pivotably journalled in one and the same point 5 on a carrier 4a. The legs of the demolisher are furthermore connected to each other by a double acting hyd¬ raulic cylinder 6 which is connected to the hydraulic sys¬ tem of the tool carrier 2 and performs the gripping and/or demolishing work to be done. At the reference numeral 7 in the Figure it appears how the carrier 4a in a way known per

se is pivotally arranged on the tool carrier 2. The pos¬ sible end positions for the respective legs are shown with dash-dotted lines. By arranging a return spring 8 between the leg 2 and the carrier 4a both the legs 1 and 2 may after each operation assume a service-friendly starting position which is such that the operator always knows from which position the legs will start.

Fig. 6 shows an arrangement which is substantially analogous to the one shown in Fig. 5 but on which a couple of other qualities have been added. A hydraulically manoeu- vered locking cylinder 9 may if required lock the leg 2 to the carrier 4, whereby, however, the positive feature with bending moment equalization will disappear. Moreover, each demolisher leg 1 and 2 has been provided with a shoulder 12 which stops pivoting of the legs into angles that only make the demolisher difficult to handle.

Fig. 7 shows last but not least an embodiment of a demolisher in which two hydraulic cylinders 6 are used instead of only one. In this embodiment the hydraulic cylinders 6 act between a couple of legs 3 arranged in front of each other and a distance piece 10 which is freely pivotally journalled on a carrier 4a as in the embodiments described above. The arrangement according to Fig. 7 gives a better control and of course a greater potential force when gripping/cutting than the earlier described embodi¬ ments.

The invention has been described in detail above with reference to a specific embodiment, which by no means should be seen as delimiting for the invention which is defined by the enclosed claims.