The present invention relates to a device for detecting leaks in a hydraulic cylinder, comprising: a first pressure sensor for detecting a pressure value in a first pressure chamber of a hydraulic cylinder, a second pressure sensor for detecting a pressure value in a second pressure chamber of the hydraulic cylinder, an evaluation unit for continuously detecting the pressure values of the first pressure sensor and the second pressure sensor, the evaluation unit being designed to detect a leak, preferably an internal leak, in the hydraulic cylinder that deviates from the norm based on the pressure values recorded by the first pressure sensor and the second pressure sensor.

A working cylinder has a cushioned end-stroke. The piston unit has a piston main part and a ring body. The exterior of the ring body receives a piston ring with a piston ring gap, and the ring opening of the ring body receives a guiding pin of the piston main part. A ring gap is formed between the ring body and the guiding pin, and the ring body has axial and radial play relative to the piston main part. The ring body has an axial ring surface on the piston main part side, and the piston main part has an axial counter ring surface on the ring body side opposite the axial ring surface. The piston unit is constructed so that during an inward movement into the cushioning zone, the piston ring passes axially over the pressure medium connection and the piston unit encloses a damping pressure medium volume. The piston unit is in a first operating state during an inward movement and a second operating state during an outward movement. In the first operating state, the axial ring surface and the axial counter ring surface lie against each other and define a seal plane the piston ring gap is configured for a throttled outflow of the damping pressure medium volume. In the second operating state, the axial ring surface and the axial counter ring surface have an axial gap for a pressure medium inflow.

An abradable seal includes an outer ring arrangement and an energiser for urging said outer ring arrangement against an opposing surface, wherein an outermost surface of said outer ring arrangement defines a sealing surface of said abradable seal; wherein said outer ring arrangement is configured such that after a first period of operation said sealing surface suddenly transitions from having a relatively large surface area to having a relatively small surface area, so as to cause a sudden increase in internal leakage across the seal at said transition.

A piston for a fluid-actuated working cylinder, with a piston base unit which is coaxial to a piston longitudinal axis, consisting of a rigid core body which has radial outer peripheral surface and of an annular filling body which is seated in an annular receiving groove. The receiving groove is coaxial to the piston longitudinal axis and in the region of the radial outer peripheral surface is designed with a radially outwardly facing groove opening in the core body. The piston further includes a ring element which consists of plastic. The ring element radially outwardly coaxially encompasses the piston base unit at least in the region of the filling body, being radially supported with a radial inner peripheral surface on the piston base unit, projecting radially beyond the radial outer peripheral surface of the core body and comprising an axially orientated axial support surface radially outside the piston base unit on its two axial face sides. The piston further includes an annular enveloping body which has rubber elastic characteristics.

A fastener driving tool with a working cylinder and a piston, the piston outer surface having a lubricant-saturated foam material that stores and dispenses lubricant into the piston-cylinder wall interface, thereby increasing the performance and lifespan of the tool. Another embodiment discloses a two-part piston in which the bottom portion is made of metal and absorbs the main mechanical loading forces of the piston drive and return strokes, and the top portion is made of a non-metallic material that has surfaces that act as sliding bearings against the inner wall of the cylinder.

The invention relates to a ring seal for sealing a gap between two parts that can be moved axially to one another, with a cross-sectional profile, which is constant in the circumferential direction and has a symmetrical design with respect to a radially oriented axis of symmetry (S), and with a dynamic sealing surface arranged radially outside or radially inside on the cross-sectional profile, and a groove base area arranged radially opposite the sealing surface, wherein that the sealing surface has a first central section (I) which, in the cross-sectional profile, has a radius R of R<B/2 with respect to an axial width B of the ring seal, and the sealing surface further has a second and third section (II, III) which enclose the first central section between them, and that the sealing surface in the region of the second and third sections (II, III) is in each case embodied as a planar annular surface which is oriented at an angle (α) of 60 to 85 degrees with respect to the axis of symmetry of the cross-sectional profile.

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.

A pressure regulator for an x-ray apparatus includes a piston housing having a recess formed therein and a piston seated in the recess. The piston is free to reciprocate, and define a variable volume chamber, within the recess. A circumferential groove is formed in an exterior surface of the piston, and a seal is seated in the circumferential groove. A manifold in the piston housing places the chamber in fluid communication with an exterior of the piston housing.

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.

A wear ring for guidance of two machine components are arranged movably relative to one another along/around a movement axis, which is formed in one piece from a plastic or a reinforced plastic material and which is slit such that it has two free ends. The wear ring has a cross-sectional width W, which at least sectionally, increases in a radial direction towards the rear side of the wear ring. The wear ring has one or more recesses formed on its front side and/or on its the rear side for increasing its deformability and thus facilitate mounting thereof in a mounting groove of a machine element. Furthermore, a wear ring arrangement with a wear ring can be clipped into a mounting groove of one of the machine components of the wear ring arrangement.