Machine and method for making pulley grooves or the like

Claim 2

A machine to form a radially extending deformation in a cylindrical wall of a hollow sheet metal workpiece of cup-shape with a bottom end and an open end comprising a base including a centering ring, a centering plate located within the centering ring, first means supporting the plate on the base for controlled movement along the axis of the plate, said plate including means to receive and support said open end of a workpiece to be deformed, a form ring carried by the centering plate and embracing a portion of a workpiece supported on the centering plate, said machine including an upper tool part having a holddown section for hold down engagement with the form ring, a die and forming punch mounted within the holddown section and movable axially relative to the hold-down section, said punch being hollow and fitting over the outside and engaging the bottom end of said cup-shaped workpiece, second means for axially moving the hold-down section, third means for axially moving the die punch, said die punch having a radial surface cooperating with the forming ring to provide a cavity adjacent the cylindrical wall of the workpiece and to shape the radial deformation that is to be formed therein, and fourth means for supplying pressure fluid to the interior of the workpiece to expand a portion thereof into said cavity including communicating passages in the base and in the centering plate.

Claim 3

A machine as set forth in claim 1 wherein the die punch and fourth means are constructed to apply axial force to the workpiece after the workpiece is filled with pressure fluid.

Claim 4

A machine as set forth in claim 2 wherein said workpiece has a vent opening, and wherein the die punch is constructed and arranged to vent said workpiece vent opening prior to application of axial force and to seal the workpiece vent opening upon application of axial force by the punch to the workpiece.

Claim 5

A machine aS set forth in claim 1 wherein said centering ring, hold-down section, centering plate, and forming ring have engaging conical surfaces, said forming ring being split and cammed in place by said centering ring.

Claim 6

A machine as set forth in claim 1 wherein said base includes a sealing ring for the pressure fluid passages engaged by said centering plate when held down by the hold-down section.

Claim 7

A machine as set forth in claim 1 wherein said first means includes pressure fluid operated ejector rods and pistons within the base and secured to the centering plate.

Claim 8

A machine to form a radially extending deformation in a cylindrical wall of a hollow sheet metal workpiece comprising a base including a centering ring, a centering plate located within the centering ring, first means supporting the plate on the base for controlled movement along the axis of the plate, said plate including means to receive a workpiece to be deformed, a form ring carried by the centering plate and embracing a portion of a workpiece supported on the centering plate, said machine including an upper tool part having a hold-down section for hold down engagement with the form ring, a die and forming punch mounted within the hold-down section and movable axially relative to the hold-down section, second means for axially moving the hold-down section, third means for axially moving the die punch, said die punch having a surface cooperating with the forming ring to provide a cavity adjacent the cylindrical wall of the workpiece to shape the radial deformation that is to be formed therein and means for supplying pressure fluid to the interior of the workpiece to expand a portion thereof into said cavity including communicating passages in the base and in the centering plate, said die punch being constructed and arranged to apply axial force to the workpiece after the workpiece is filled with pressure fluid, said workpiece being cup-shaped with an annular rim at its open end, the bottom end of the workpiece having an opening therein, said centering plate being shaped to receive said rim, said form ring fitting on top of said rim, said die punch including vent passages communicating with said workpiece opening to vent said workpiece prior to application of axial force, said die punch including sealing means for closing said workpiece opening upon application of axial force by the punch to the workpiece when said die punch contacts the bottom end of the workpiece.

Claim 9

A machine to form a radially extending deformation in a cylindrical wall of a hollow sheet metal workpiece comprising a base including a centering ring, a centering plate located within the centering ring, first means supporting the plate on the base for controlled movement along the axis of the plate, said plate including means to receive a workpiece to be deformed, a form ring carried by the centering plate and embracing a portion of a workpiece supported on the centering plate, said machine including an upper tool part having a hold-down section for hold down engagement with the form ring, a die and forming punch mounted within the hold-down section and movable axially relative to the hold-down section, second means for axially moving the hold-down section, third means for axially moving the die punch, said die punch having a surface cooperating with the forming ring to provide a cavity adjacent the cylindrical wall of the workpiece to shape the radial deformation that is to be formed therein and means for supplying pressure fluid to the interior of the workpiece to expand a portion thereof into said cavity including communicating passages in the base and in the centering plate, said die punch being constructed and arranged to apply axial force to the workpiece after the workpiece is filled with pressure fluid, said workpiece being cup-shaped with an annular rim at its open end, the bottom end of the workpiece having an opening therein, said centering plate being shaped to receive said rim, said form ring fitting on top of said rim, said die punch including vent passages communicating with said workpiece opening to vent said workpiece prior to application of axial force, said die punch including sealing means for closing said workpiece opening upon application of axial force by the punch to the workpiece when said die punch contacts the bottom end of the workpiece.