Shock absorbing mechanism in automatic analyzing and measuring apparatus

Claim 1

A shock absorbing mechanism in an automatic analyzing and measuring apparatus of the type having an optics/dispensing device and an X-Y drive mechanism for transporting the optics/dispensing device in two dimensions, which X-Y drive mechanism has X and Y bidirectional drive sources each including a reversible drive motor and a corresponding power transmission sprocket for transmitting power from the motor to the optics/dispensing device, said shock absorbing apparatus comprising a slip clutch interposed between each drive motor and corresponding power transmission sprocket, said slip clutch comprises balls, a clutch plate, a ball retaining plate, said power transmission sprocket, and a guide plate, said clutch plate being fixedly secured to a drive shaft, said ball retaining plate, sprocket and guide plate being supported on said drive shaft for rotation, said clutch plate provides holes bored through an outer circumferential portion thereof alignable with holes bored in said sprocket, said ball retaining plate being disposed between said clutch plate and said sprocket and being freely rotatable with respect thereto, said ball retaining plate providing holes each retaining a respective ball, said balls cooperating with said clutch plate holes and sprocket holes to transfer torque from said drive shaft to said sprocket, said ball retaining plate, sprocket and guide plate being axially displaceable along said drive shaft from said clutch plate, said drive shaft having a stopper affixed thereto and a spring being compressed between said guide plate and the stopper for urging said ball retaining plate, sprocket and guide plate toward said clutch plate for operative association therewith, whereby when said sprocket is subjected to an excessive force said balls slip out of one of said clutch plate holes and sprocket holes causing said guide plate to move axially away from said clutch plate against said spring and actuate a switch so as to halt said drive motor.