Patent ID: 6490904
Filing Date: 2002-12-10
Classification: B21D

Abstract:
An improved double action bottom former capable of high cyclic operation to form and shape metal can blanks, said double action bottom former comprising:an integral cylinder housing member having a first end portion and a second end portion, said first end portion having sidewalls defining a first axial chamber, said second end portion having sidewalls defining a second axial chamber, said sidewalls of said first end portion comprising a plurality of axially oriented bores extending the length of said first end portion of said integral cylinder housing member into said second axial chamber; pushrod means comprising a plurality of pushrods slidably positioned within said axially oriented bores; tool set means located within said first end portion of said integral cylinder housing member for engaging and forming a metal can blank and for transferring the resultant force to said pushrod means; piston means for providing suspension for said pushrod means, said piston means comprising a piston member movably positioned within said second axial chamber, said piston member comprising a concave-shaped bottom having a concave receiving surface and an annular piston wall attached to the periphery thereof to form a centralized cavity, said annular piston wall comprising a contact surface geometrically configured to engage said pushrod means extending into said second axial chamber, said concave receiving surface being substantially opposite of said contact surface for receiving a pressurized medium to resiliently position said pushrod means and tool set means as the metal can blank engages tool set means to produce a corresponding force against said pushrod means and cause axial transfer thereof to said piston member; and biasing means for secondary resilient positioning of tool set means, said biasing means comprising a donut spring having an interior cylindrical space defining a third axial chamber and being further defined in part by a cover plate and a plurality of apertures extending therethrough and circumferentially thereabout for passage of an equal number of standoff tubes, said cover plate having a large aperture extending there-through and in axial alignment with said integral cylinder housing member to provide hydraulic communication between second and third axial chambers, said cover plate and donut spring cooperating with an end spring plate to effectively bias said integral cylinder housing member in the direction of said first end portion of said integral cylinder housing member.