Abstract: A holding fixture includes a first part, a securing member and a second part. The first part includes a first end face and a sleeve extending from the first end face, the sleeve defines a plurality of radial through holes each receiving a ball therein, and each ball has a diameter larger than the wall thickness of the sleeve therein. The securing member located around the sleeve includes a plurality of protrusions configured on an inner wall thereof, with every two neighboring protrusions defining a notch therebetween. The second part includes a body and a tail fixed on the body, with seating thereof in the sleeve enabled by an annular groove in the periphery thereof. The protrusions guide the balls into the annular groove to secure the second part on the first part.

Abstract: A punching assembly includes a die base, a sleeve, an adjusting screw, a pull portion, a latching block, an elastic element, a fixing ring and a stop member. A top of the die base is received in the sleeve. The adjusting screw includes a contact end, a mounted end inserting into the sleeve and connecting to the top of the die base, and a latching portion located between the contact end and the mounted end. The pull portion is disposed around the sleeve. The latching block engages the latching portion. The elastic element is disposed around the adjusting screw, supporting the latching block. The fixing ring surrounding the adjusting screw is fixed on the sleeve. The stop member, contiguous with the fixing ring, prevents axial movement of the adjusting screw.

Abstract: A press brake tool for bending a workpiece includes a punch having a punch tip, a press brake die and a die holder fixing the die thereto. The press brake die includes a pair of rotary members and at least one elastic member. The press brake die further defines an elongated lateral groove facing the punch tip and at least one longitudinal through hole communicating with the lateral groove. The pair of rotary members is spaced from each other and rotatably received in the elongated lateral groove. The at least one elastic member is received in the at least one longitudinal through hole and abutting the pair of rotary members.

Abstract: A positioning apparatus (10), mounted on a machine tool (60), for positioning a workpiece (30) on the machine tool, comprises a positioning member (12), at least one sliding element (14), and at least one positioning element (18). The positioning member comprises a first portion (120) comprising a recessed portion (122) and at least one receiving hole (128). The sliding element slidably received in the recessed portion, the sliding element comprising a first engaging portion (142). The positioning element comprises a second engaging portion (182) and a positioning portion (186) connected to the second engaging portion. The second engaging portion extends through the receiving hole and is engaged with the first engaging portion.

Abstract: An active power factor correction circuit. The circuit comprises a voltage source having a first end and a second end, an inductor having an end coupled to the first end of the voltage source, a first rectifying device having an anode coupled to the other end of the inductor and a cathode, a second rectifying device having a cathode coupled to the cathode of the first rectifying device and an anode, a first switching device having a first terminal coupled to the anode of the first rectifying device and a second terminal, a second switching device, having a first terminal coupled to an anode of the second rectifying device and the second end of the voltage source and a second terminal, a capacitor having two ends coupled to the cathode of the second rectifying device and the second terminal of the second switching device respectively, and an auxiliary circuit for switching the first and second switching devices under zero voltage.

Abstract: An active power factor correction circuit. The circuit comprises a voltage source having a first end and a second end, an inductor having an end coupled to the first end of the voltage source, a first rectifying device having an anode coupled to the other end of the inductor and a cathode, a second rectifying device having a cathode coupled to the cathode of the first rectifying device and an anode, a first switching device having a first terminal coupled to the anode of the first rectifying device and a second terminal, a second switching device, having a first terminal coupled to an anode of the second rectifying device and the second end of the voltage source and a second terminal, a capacitor having two ends coupled to the cathode of the second rectifying device and the second terminal of the second switching device respectively, and an auxiliary circuit for switching the first and second switching devices under zero voltage.

Abstract: The present invention provides a water soluble polymer which is prepared by the following steps. First, a carboxyl group-containing polymer is reacted with an alkaline reagent so that a portion of the carboxyl groups are reacted in an amount sufficient to make the polymer water soluble. Then, the polymer obtained is reacted with an epoxide containing unsaturated bonds and/or heteroatoms so that 1 to 100 mole percent of the remaining carboxyl groups of the polymer are reacted with the epoxide to form ester groups via a ring-opening reaction of epoxides, wherein the heteroatom can be silicon, nitrogen, phosphorus or sulfur. The water soluble polymer of the present invention can be used as a photosensitive resin. When the photoresist composition is used for preparing printed ciruit boards, it exhibits high photosensitivity, good water dispersability, storage stability, and good adhesion to copper. In addition, the problem of sticking to the mask can be prevented.

Abstract: A tile cutting device is composed of a base, two support frames, two guide rods, a slide seat, a cutting tool seat, a cutting tool, and a grip rod. The base is provided at one longitudinal side thereof with an auxiliary base which is detachably fastened therewith such that the upper surface of the auxiliary base is flush with a tile placing surface of the base, and that the auxiliary base gives an added width to the base to accommodate a large tile to be worked on by the tile cutting device. The auxiliary base can be unfastened and kept in the underside of the base.

Abstract: A ceramic tile cutter is provided with at least one auxiliary base which is fastened pivotally with one longitudinal side of a base of the ceramic tile cutter such that the upper surface of the auxiliary base is lower than the crest of a ridged portion of the base. The auxiliary base can be swiveled to give an added width to the base so as to facilitate the locating of an oversize ceramic tile on the base of the ceramic tile cutter.