Retaining mechanism for lapping device

Abstract

A quick change lap retaining device uses radially displaceable blades to engage a groove in the underside of a lap and thereby hold the lap in position. The device fails in the engaged position to prevent inadvertent movement of the lap. Removal of the lap occasioned by disengagement of the blades is preferentially by pneumatic drive but can also be manual.

What is claimed is:  
     
         1 . A lap retainer system comprising: 
 a lap support;    a shaft rotatably passing through said support;    a blade attached to said shaft and rotatable therewith, said blade being engageable with a lap; and    an actuation system operably coupled with said shaft to rotate said shaft and thereby rotate said blade.    
     
     
         2 . A lap retainer as claimed in    claim 1    wherein said shaft is two shafts, each shaft having a blade attached thereto, both of said blades being engageable with said lap.  
     
     
         3 . A lap retainer as claimed in    claim 2    wherein said two shafts are interconnected with said actuation system.  
     
     
         4 . A lap retainer as claimed in    claim 3    wherein said actuation system interconnects said two shafts by linkage to a driver, said linkage translating motion of said driver to rotate said two shafts.  
     
     
         5 . A lap retainer as claimed in    claim 1    wherein said actuation system is one of hydraulically, pneumatically, electrically, electromechanically and mechanically driven.  
     
     
         6 . A lap retainer as claimed in    claim 1    wherein said actuation system is manually operable.  
     
     
         7 . A lap retainer as claimed in    claim 1    wherein said blade is keyed to said shaft.  
     
     
         8 . A lap comprising: 
 a domed top portion;    an annular skirt depending from said top portion;    a hollowed interior;    an annular groove in said skirt said groove being open to said hollowed interior and closed to an exterior of said skirt.    
     
     
         9 . A lap as claimed in    claim 8    wherein said domed top portion is of constant thickness.  
     
     
         10 . A method for retaining a lap comprising: 
 supporting a lap on a lap support, said lap having an annular groove on an internal aspect thereof; and    engaging said groove with a blade disposed under said lap when supported by said support.    
     
     
         11 . A method as in    claim 10    wherein said engaging comprises: 
 Rotating a shaft extending through said support and into connection with said blade, to move at least a part of said blade to a position radially outwardly from an unrotated position.  
 
     
     
         12 . A method as in    claim 11    wherein said rotating is by spring bias and said unrotated position is achieved by operating an actuator to overcome said spring bias.