Expandable type lid welding piston
AssigneeAkerlund & Rausing Licens Aktiebolag
InventorsRune Dahlin, Gustaf Linderoth
Life of this patent
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Abstract
A plunger (4) for joining an inner workpiece (7) to an outer tubular workpiece (2) is disclosed. The plunger includes an expansion element (9) which engages the inner workpiece and crimps it to the outer workpiece. The expansion element (9) is an annular cup-shaped resilient element which is mounted on a part (21) which is movable relative to a body (8) and to a bottom plate (16). The body (8) and its bottom plate (16) are provided with guide surfaces which are spaced apart to provide a space through which the expansion element may pass upon movement of member 21. The guide surfaces constrain the resilient expansion element to move into pressure applying engagement with the inner workpiece.
Claims8
A plunger for exerting a radially outward force around an inner surface of a workpiece that substantially surrounds it, said plunger comprising an upper part and a lower part, one of which parts is movable axially towards the other to an expansion position and away from the other to a contraction position, said lower part having a periphery which substantially corresponds in shape to the interior cross-section of said workpiece, and an expansion element which is confined between said upper and lower parts and which is resiliently deformable to be radially expanded for exerting said force in consequence of axial movement of said one part towards said expansion position, said plunger being characterized by:
- A. said lower part comprising a bottom member having a top surface which extends radially outwardly to said periphery all around the same;
- B. said expansion element comprising a substantially annular resiliently deformable wall having a radially inner portion and a radially outer edge,
- (1) said radially inner portion being secured to said upper part, and
- (2) said wall being formed and arranged for such cooperation with said upper and lower parts that,
- (a) with said one part in its contraction position
- (i) said wall has a downwardly divergent form with substantially all portions thereof extending obliquely downwardly and radially outwardly from said upper part and
- (ii) the radially outer edge of said wall is adjacent to said periphery all around the same and does not project substantially beyond said periphery, and
- (b) as said one part is moved to its expansion position the radially outer edge portion of said wall is spread by sliding engagement with said top surface to thus radially expand the radially outer edge of said wall.
Dependencies are inferred from the claim text.