Abstract: An adjustable door closer has a hollow pedestal with a first and a second chamber as well as an actuating groove. An actuating device is set into the actuating groove. A first piston assembly is set into the first chamber and a second piston assembly set into the second chamber. A partition wall is formed between the first and second chambers. Due to a laterally configured flow resistance unit, the holes to be set into the first and second chambers are reduced to three, including a no connecting hole and first and second backflow bypass holes, all of which are connected only to the second chamber from the partition wall. As such, the flow path structure is simplified compared to the five holes required for typical structures. The adjustable door closer could reduce significantly the manufacturing cost and realize better regulating functions with improved applicability and economic benefits.

Abstract: An adjustable door closer has a hollow pedestal with a first and a second chamber as well as an actuating groove. An actuating device is set into the actuating groove. A first piston assembly is set into the first chamber and a second piston assembly set into the second chamber. A partition wall is formed between the first and second chambers. Due to a laterally configured flow resistance unit, the holes to be set into the first and second chambers are reduced to three, including a connecting hole and first and second backflow bypass holes, all of which are connected only to the second chamber from the partition wall. As such, the flow path structure is simplified compared to the five holes required for typical structures. The adjustable door closer could reduce significantly the manufacturing cost and realize better regulating functions with improved applicability and economic benefits.

Abstract: A brake master cylinder of the invention is to dispose a main oil cylinder and an oil storing space on a handlebar base. In addition, a sleeve engaged with the main oil cylinder is disposed in the oil storing space. The one end of the oil storing space has a fastening seat passed by a draw bar linked to the brake handlebar, and a positioning sheath of the fastening seat is utilized to engage with the sleeve. A leakage prevention component is disposed between the fastening seat and the handlebar base. A bushing integrally extended from the leakage prevention component is utilized to encapsulate the positioning sheath of the fastening seat and the sleeve. Accordingly, the brake master cylinder having convenient assembly and better sealing effect for hydraulic oil is obtained.

Abstract: The present invention provides an adjustable hinged door closer, including a seat with the first and second cylinders, and a first and a second elastic linkage unit. A double-threaded regulator is incorporated onto the first connecting rod of the first elastic linkage unit, so as to change the compression of the spring and regulate the closing/restoring force of the door body. The double-threaded column of the double-threaded regulator has a double-thread that shifts to two thread pitches by just making one rotation, thus facilitating the fine-tuning easily. The elastic linkage unit and the regulator are structurally configured to be assembled externally, and then mated with the connecting seat of the door closer.

Abstract: The present invention provides an adjustable hinged door closer, including a seat with the first and second cylinders, and a first and a second elastic linkage unit. A double-threaded regulator is incorporated onto the first connecting rod of the first elastic linkage unit, so as to change the compression of the spring and regulate the closing/restoring force of the door body. The double-threaded column of the double-threaded regulator has a double-thread that shifts to two thread pitches by just making one rotation, thus facilitating the fine-tuning easily. The elastic linkage unit and the regulator are structurally configured to be assembled externally, and then mated with the connecting seat of the door closer.

Abstract: A door closer includes a casing having a recess in which a base is received, and a first cylinder and a second cylinder are in communication with the recess. A passage is in communication between the first and second cylinders so as to allow the hydraulic oil to flow between the two cylinders. The base includes a driving shaft for being connected to a door. A first rod and a second rod are pivotably connected to the base and respectively inserted in the first and second cylinders. A threaded rod is connected to a distal end of the first rod and a first spring is mounted to the first rod and the threaded rod. A sleeve is threadedly engaged with the threaded rod and an operation rod is securely connected to the sleeve so that when rotating the operation rod, the first spring is adjusted by moving the sleeve relative to the threaded rod.

Abstract: A door closer includes casing fixedly fastened to a door frame, a hydraulic cylinder installed in the casing and holding a hydraulic fluid, a coupling block installed in one end of the hydraulic cylinder, the coupling block having a pivot shaft connected to a door, and a reciprocating mechanism coupled to the coupling block, fluid velocity regulating valves installed in the casing and controlled to adjust the velocity of the hydraulic fluid flowing in the casing, the reciprocating mechanism including a double-threaded adjustment rod for adjusting the spring power of compression springs thereof.