Abstract: A U ring in an inwardly radially-open groove in a relatively stationary machine part for sealing a relatively axially-displaceable machine part extending therethrough has a resilient U ring body, a radially-outside statically-acting sealing lip for bearing on the bottom of the groove, and a radially-inside dynamically-acting sealing lip for bearing on the axially-displaceable machine part. The axial spacing of the statically-acting sealing lip from the adjacent end face of the groove is greater than that of the dynamically-acting sealing lip, whereby the dynamically-acting sealing lip tilts away from the axially-movable machine part when the latter forces the end of the U ring against the end face of the groove to relieve pressure along the axially-moving machine part.

Abstract: A joint pin seal for a caterpillar track. The join pin seal comprises a support ring of hard elastomer material having a cylindrical inner wall. The support ring is firmly pressed in a housing bore which is adjacent a relatively movable machine part to be sealed. The support ring comprises a stiffening ring contacting the rear wall of the housing bore and a lip ring adjacent the machine part to be sealed. The lip ring has a sealing lip which presses against the surface of the machine part to be sealed. The stiffening ring is tapered in notch-like fashion into said lip ring forming a membrane at the transition into the lip ring and provides the support ring with a notch between the lip ring and the stiffening ring. A pressure ring, formed from a softer elastomer material, is disposed within the notch and contacts the housing bore wall. The pressure ring presses the sealing lip into the relatively movable machine part to be sealed.

Abstract: A ring which provides efficient sealing against pressure differentials. The ring is an elastomer, cylindrical body with a bore, an inside face having inner and outer sealing lips, an outside face having an inner wiping lip and an outer support arm, and an annular support projection joining the outside wall of the body.

Abstract: A piston for use in pneumatic cylinders includes a tubular support with flange-like parts, a reinforcement ring received in the support and having a groove on its outside circumference, a guide ring rigidly mounted in the groove, and angular packing washers pre-vulcanized onto the reinforcement rings on both sides of the guide ring.

Abstract: A sealing ring for a piston moving within a cylinder made up of an elastomeric part and a stiff support part, the ring being x-shaped in cross section, two legs of the elastomeric part, of the same radius, constituting the dynamic seal and a third leg constituting the static seal. The fourth leg is made up by the support part and projects radially beyond the third leg so as to lock into a corresponding recess is the piston or cylinder. An indentation about the circumference of the fourth leg facilitates its resilient flexing to make the initial lock. Advantageously the axial body of the seal between the legs is substantially cylindrical.