An end effector coupler for a surgical arm can include a body, a proximalcoupler, and a tool lock. The tool lock can releasably retain a tool stem tothe endeffector coupler. The tool lock can include a keyed opening, a pin bore, a pindisposed in the bin bore, a biasing element located in the pin bore, and a pinreleaseincluding an actuator, the pin release operable to retract the pin into to thebody todisengage the pin from the tool stem allowing release of the tool stem fromthekeyed opening.
