Method for repairing a piston-cylinder unit within a working machine

Abstract

Disclosed is a method for repairing a piston-cylinder unit within a working machine or within an attachment, wherein a connection of the piston rod with the machine or implement structure is released and the piston rod, the piston and at least one bearing head is jointly removed from the cylinder housing as an assembly and replaced by a premounted substitute assembly consisting of piston rod, piston and at least one bearing head.

Claims

1. A method for repairing a piston-cylinder unit within a working machine or within an attachment, the method comprising: disconnecting a piston rod of the piston-cylinder unit from the working machine or implement structure by releasing a bolt connection of a lug with the working machine, wherein the lug is at a first end of the piston rod; jointly removing the piston rod, a piston, and at least one bearing head from a cylinder housing assembly; and inserting a pre-mounted substitute assembly comprising a second piston rod, second piston, and at least one bearing head into the cylinder housing assembly as a replacement; wherein a cylinder of the piston-cylinder unit remains mounted on the working machine during the repair.

2. The method according to claim 1, wherein the substitute assembly is a mounted piston comprising the second piston rod with a fitted bearing head.

3. A method for repairing a piston-cylinder unit within a working machine or within an attachment, the method comprising: disconnecting a piston rod of the piston-cylinder unit from the working machine or implement structure by releasing a bolt connection of a lug with the working machine, wherein the lug is at a first end of the piston rod; jointly removing the piston rod, a piston, and at least one bearing head from a cylinder housing assembly; and inserting a pre-mounted substitute assembly comprising a second piston rod, second piston, and at least one bearing head into the cylinder housing assembly as a replacement; wherein, when disconnecting the piston rod, only a fastening of the at least one bearing head to a cylinder opening is released, and wherein the fastening is a screw connecting the cylinder housing and the at least one bearing head.

4. The method according to claim 1, wherein the piston and/or the at least one bearing head of the substitute assembly have a set of sealings.

5. The method according to claim 1, wherein the working machine is a construction machine, a crane, or a working machine for material handling or the attachment is a grab, and the piston-cylinder unit to be repaired is a grab cylinder of the grab.

6. A method for repairing a piston-cylinder unit within a working machine or within an attachment, the method comprising: disconnecting a piston rod of the piston-cylinder unit from the working machine or implement structure by releasing a bolt connection of a lug with the working machine, wherein the lug is at a first end of the piston rod; jointly removing the piston rod, a piston, and at least one bearing head from a cylinder housing assembly; and inserting a pre-mounted substitute assembly comprising a second piston rod, second piston, and at least one bearing head into the cylinder housing assembly as a replacement; wherein the piston is fixed on the piston rod via a nut and locking ring.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further advantages and properties of the invention will be explained below with reference to an exemplary embodiment shown in the Figures, in which:

(2) FIG. 1: shows a first exemplary embodiment of the installation kit according to the disclosure for a piston-cylinder unit within a working machine, and

(3) FIG. 2: shows an alternative embodiment of the installation kit according to the disclosure.

DETAILED DESCRIPTION

(4) Beside the cylinder housing 10, FIG. 1 shows the installation kit according to the invention in an exploded representation. The installation kit comprises the corresponding assembly consisting of a piston rod 11, the fitted bearing head 13 and the premounted piston 12. At its end, the piston rod 11 comprises the corresponding lug 34 for mounting on the machine structure of a working machine. For this purpose, a corresponding steel bush 1 is inserted into the lug, the radial bore serves to accommodate a lubricating nipple, in particular a conical lubricating nipple 20, which serves for the sufficient lubrication of the lug. The lubricating nipple can also be contained in the installation kit.

(5) At its end, the piston rod 11 comprises a thread on which the appropriate piston 12 can be placed. At its end, the piston 12 is fixed on the piston rod 11 with a nut 4 and the locking ring 25. The piston 12 carries sealing rings which are delivered already mounted together with the installation kit. The bearing head 13 can be screwed to the opening edge of the cylinder housing 10 by means of the hexagon screws 21. The bearing head also has already been provided with the corresponding sealing package at the factory. The hexagon screws 21 can also be contained in the installation kit. Instead of the aforementioned screw connection of the bearing head 13 with hexagon screws, the bearing head 13 can also be provided with an external thread. Such a bearing head not shown here can be screwed into the cylinder 10 via an appropriate counter-thread in the region of the cylinder opening.

(6) According to the method of the invention, the entire assembly A is sold as a spare part and can easily be inserted on the spot as a complete unit into a cylinder 10 to be repaired. For this purpose, the defective assembly is removed from the cylinder 10 by releasing the bolt connection of the lug with the machine structure and by unscrewing the hexagon screws 21 of the bearing head. The entire assembly can then be pulled out of the cylinder 10. The installation of the substitute assembly is effected in reverse order, i.e. the assembly is pushed into the cylinder 10 with the premounted piston 12 first, and the bearing head 13 is moved to the corresponding position of the cylinder opening until the screws 21 can be screwed in. Finally, the lug of the piston rod 11 is connected to the machine structure. Experience has shown that the entire repair operation can be carried out within about 15 minutes.

(7) A slightly alternative configuration of the installation kit is shown in FIG. 2, wherein it also applies for this installation kit that the entire assembly A′ is delivered premounted and is incorporated into the cylinder 10 as a whole.

(8) By offering the completely premounted piston rod assembly with fitted bearing head and mounted piston as an assembly several advantages are obtained:

(9) The Time Factor:

(10) By means of the installation kit the time for disassembly and assembly can be reduced distinctly (to about 15 min). It is merely necessary to release the bearing head at the piston-cylinder unit to be repaired; subsequently, the complete package can be removed from the cylinder tube and the new package can be inserted. No special tools are required and the cylinder repair can also be effected on the spot at the construction site.

(11) The Cost Factor:

(12) In the event of damage, a substitute is available by means of the installation kit as quickly as in the presence of a new hydraulic cylinder. Such a kit, however, is a much more economical solution than a completely new hydraulic cylinder.

(13) The Quality Factor:

(14) Due to the premounted piston rod assembly no special tools are required anymore, which often are missing in the individual repair facilities. As the mounting of the assembly is effected in the factory of the manufacturer, the risk of errors or damages during disassembly and assembly can thus be minimized, and it is ensured in addition that exclusively original spare parts are used.

(15) The method according to the invention is expedient in particular where smaller hydraulic cylinders are used in the field of working machines, for example in attachments or smaller earth-moving machines in excavators, wheel loaders or bulldozers. However, there is no reason why the idea underlying the invention should not also be selectively used for larger hydraulic cylinders.