Abstract: Piston-ringing apparatus comprises a tubular piston nest member for receiving each piston to locate the piston groove in a predetermined ring-receiving position, a plurality of ring cartridges positionable one at a time in alignment with the piston nest member. The aligned ring cartridge is engaged to the piston nest member to permit transfer of rings from the ring cartridge to the piston nest member and disengage the aligned ring cartridge when empty of rings. The stack of rings on the cartridge is moved by opposing fingers toward the piston groove to position an endmost ring residing on the nest member in the groove of each successive piston received in the nest member while the aligned ring cartridge is engaged thereto. A fiber optic switch is provided for directing a light beam tangentially through the piston groove to determine whether a ring is positioned therein. The switch provides a finger motor drive signal to stop feeding of a ring to the piston groove when a ring is present in the piston groove.

Abstract: Method for assembling a piston ring in a circumferential groove of a piston wherein a plurality of ring nest members are disposed about a common axis for radial movement toward or away from the axis between radially contracted positions and radially expanded positions, The nest members collectively form a circular opening concentric with the axis and a ring-receiving recess concentric about the opening when they are in the contracted positions. The ring nest members are movable from the radially contracted to the expanded positions when the ring is expanded so as to collectively enlarge the opening for receiving the piston and the recess to maintain the expanded ring substantially concentric with the axis while the fixed axial dimension prevents "oil canning". A plurality of radially and axially movable ring expanding fingers are disposed about the axis and positionable in the opening for radially expanding the ring while it resides in the recess.

Abstract: Piston-ringing apparatus comprises a tubular piston nest member for receiving each piston to locate the piston groove in a predetermined ring-receiving position, a plurality of ring cartridges positionable one at a time in alignment with the piston nest member. The aligned ring cartridge is engaged to the piston nest member to permit transfer of rings from the ring cartridge to the piston nest member and disengage the aligned ring cartridge when empty of rings. The stack of rings on the cartridge is moved by opposing fingers toward the piston groove to position an endmost ring residing on the nest member in the groove of each successive piston received in the nest member while the aligned ring cartridge is engaged thereto. A fiber optic switch is provided for directing a light beam tangentially through the piston groove to determine whether a ring is positioned therein. The switch provides a finger motor drive signal to stop feeding of a ring to the piston groove when a ring is present in the piston groove.

Abstract: Apparatus and method for assembling a piston ring in a circumferential groove of a piston wherein a plurality of ring nest members are disposed about a common axis for radial movement toward or away from the axis between radially contracted positions and radially expanded positions. The nest members collectively form a circular opening concentric with the axis and a ring-receiving recess concentric about the opening when they are in the contracted positions. The recess locates a radially unexpanded ring concentric with the axis and has a fixed axial dimension for preventing "oil canning" of the ring when it is expanded. The ring nest members are movable from the radially contracted to the expanded positions when the ring is expanded so as to collectively enlarge the opening for receiving the piston and the recess to maintain the expanded ring substantially concentric with the axis while the fixed axial dimension prevents "oil canning".