Abstract: A chuck includes a chassis, a support member, a number of jaws, and a number of bolts. The chassis includes a mounting portion secured to a target machine. The support member is rotatably connected to the chassis and includes a support plate defining a number of radially extending first slots. The jaws each include an engaging surface. The bolts each include a head with a diameter greater than a width of the first slot and a shank connected to the head. The shank extends through one of the first slots of the support plate and is screwed into one of the jaws for securing the one of the jaws to the support plate. The engaging surfaces of the jaws is configured to contact a top surface of a workpiece placed on the support member for holding the workpiece in position.

Abstract: A stretching device for moving one end of an elastic ring to a predetermined position is illustrated. The stretching device includes a base member, a handle, a movable member, a rotatable member, at least one connecting bar, and a positioning head fixed to the rotatable member. The handle includes at least one first bar, a first end of the at least one first bar being rotatably connected to the base member. The movable member is slidably mounted on the base member and comprising a blocking section opposite to the base member. The rotatable member includes at least one second bar, a first end of the at least one second bar being rotatably connected to the movable member. Opposite ends of the connecting bar are rotatably connected to a second end of the at least one first bar and a second end of the at least one second bar, respectively.

Abstract: A nut includes a main body. The main body includes a first end and a second end opposite to the first end. The main body defines a central threaded through hole and a receiving access along an axis of the main body. The central threaded through hole communicates with the receiving access and extends along the axis of the main body from the first end. The receiving access extends along the axis of the main body from the second end and includes at least three inner sidewalls.

Abstract: The present disclosure provides a screw with multi-hexahedron head. A head of the screw includes at least two hexahedrons which are parallel with each other. Each surface of the at least two hexahedrons is a parallelogram and parallel with the opposite face. A short height of a parallelogram bottom surface of each hexahedron is less than or equal to width of an opening of a T-shaped groove. A long height of a parallelogram bottom surface of a first hexahedron is equal to the width of the opening of the groove. A long height of a parallelogram bottom surface of a second hexahedron is greater than the width of the opening of the groove.