Patent ID: 9327411
Filing Date: 2016-05-03
CPC Classification: B25J

Claim Text:
1. A robotic gripper for gripping a target, comprising: A) two gripper fingers, each of said two gripper fingers being attached to a bearing carriage, each bearing carriage defining a rack gear and adapted to ride on a bearing rail and grip the target, B) a single pinion gear having two gear elements each of the two gear elements being meshed with one of the two rack gears so as to drive the two bearing carriages in opposite direction upon rotation of the pinion gear, C) a worm gear fixed to the single pinion gear, D) a worm screw defining a shallow screw angle and meshed to the worm gear and adapted to cause rotation of the worm gear and the single pinion gear and a gripping action or a releasing action of said two gripping fingers, depending on the direction of rotation of said worm screw, and E) a programmable controller programmed to control the motion of said gripper fingers, F) a stepper motor adapted to drive said worm screw in a first rotary direction and a second rotary direction, said stepper motor being adapted to stall when the gripper fingers have gripped the target, and; G) an encoder means connected between the stepper motor and the controller, for sending a signal to the controller to indicate when the gripper fingers have grabbed the target so that only as much current is put into the motor as required to clamp the target so that overheating is avoided; wherein when the fingers have gripped the target causing the stepper motor to stall, a signal is sent to the controller via the stepper motor and the controller turns off the power to the motor and wherein, the shallow screw angle on the worm screw is so shallow that in the event of a loss of power to the stepper motor and the worm gear tries to spin the worm screw, friction, between the worm gear and the worm screw, holds the worm screw in place and the target is not dropped.