Abstract: An epitaxial structure adapted to a semiconductor pickup element is provided. The semiconductor pickup element has at least one guiding structure and provided with a pickup portion. The epitaxial structure includes a semiconductor layer corresponding to the pickup portion and capable of being picked up by the semiconductor pickup element. The epitaxial structure also includes at least one alignment structure disposed on the semiconductor layer and corresponding to the at least one guiding structure, so that the epitaxial structure and the semiconductor pickup element are positioned relative to each other. The number of the at least one alignment structure matches the number of the at least one guiding structure.

Abstract: A ball bearing includes an outer race; an inner race including having a through hole, a first end, and an outer surface; a plurality of balls rotatably disposed between the inner race and the outer race; a washer including an inner surface attached to the outer surface of the inner race; and a welding bead formed at a joining portion of the inner surface of the washer and the first end of the inner race to secure the washer to the inner race. A number of embodiments are provided.

Abstract: An electrical ratchet wrench has a body, a motor, a battery set, a switch, a planet gear assembly, a connecting collar, a head and a ratcheting device. The motor is received in the body and has an output shaft with a pinion. The battery set is detachably received in the body and is electrically connected to the motor. The switch is electrically connected between the motor and the battery set. The planet gear assembly is received in the body and has a rotating base, a stub, multiple planet gears and a stationary collar. The connecting collar securely holds the stationary collar in the connecting collar. The ratcheting device is received in the head for driving a fastener to rotate and has a driven shaft connected to the stub on the rotating base. Accordingly, a cordless electrical ratchet wrench is provided and is convenient in use.

Abstract: An electrical ratchet wrench has a body, a motor, a battery set, a switch, a planet gear assembly, a connecting collar, a head and a ratcheting device. The motor is received in the body and has an output shaft with a pinion. The battery set is detachably received in the body and is electrically connected to the motor. The switch is electrically connected between the motor and the battery set. The planet gear assembly is received in the body and has a rotating base, a stub, multiple planet gears and a stationary collar. The connecting collar securely holds the stationary collar in the connecting collar. The ratcheting device is received in the head for driving a fastener to rotate and has a driven shaft connected to the stub on the rotating base. Accordingly, a cordless electrical ratchet wrench is provided and is convenient in use.

Abstract: A housing for a hand tool has a head, a handle and two positioning devices. The head is composed of two half casings each having a first adjusting base with a recess. The handle is pivotally attached to the head and is composed of two half casings each having a second adjusting base with a recess. The positioning devices are respectively mounted between the aligning recesses of the first and second adjusting bases on the head and the handle. Each positioning device has a pressing disk, a pressed disk and a biasing member. Each disk has a guiding block and a positioning block. The guiding block is formed on the disk and has two curved guiding edges selectively abutting against one end of the positioning block on the abutting disk. With such an arrangement, the housing can be adjusted between two positions easily and conveniently.