Abstract: A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill.

Abstract: A fluid distributor cylinder is for a percussive drill assembly that includes a casing having an inner circumferential surface defining a central bore, a central axis extending through the bore, a bit movably coupled with the casing and a piston movably disposed within the casing bore. The distributor cylinder includes a generally tubular body disposeable within the casing bore and having first and second ends, a central axis extending generally between the first and second ends, an outer circumferential surface. At least a section of the outer surface is configured to engage with the inner surface of the casing so to form an interference fit between the body and the casing. The cylinder includes an exterior thread and/or a radially-extending shoulder configured to releasably engage with the casing inner surface so as to substantially prevent axial displacement of the distributor body with respect to the casing.

Abstract: A direction switching and speed controlling device for an air tool includes two holes provided respectively on two lateral sides of an air cylinder (2). Holes on one side are two air outlets (8), and two holes on another side are a forward rotation air inlet (13) and a reverse rotation air inlet (12). An air valve (7) has an indentation portion (9) provided on a lateral side thereof, said indentation portion (9) is engaged with teeth portion (10) provided on a lower end of a switch (6). At another end, the switch (6) includes an elongated portion (11) provided horizontally with a blind hole (14) provided in the center. A spring (3) is disposed into the hole (14) with a metal ball (4) attached to an end thereof. A valve cap (5) is provided on a bottom portion of a casing (1) with a plurality of spherical grooves (15) provided therein. Said metal ball (4) and groove (15) are engaged through the restoration force of the spring (3).

Abstract: A power tool, such as a hammer drill and/or a chiseling hammer, includes a lubricated transmission arranged in a sealed transmission box. The transmission box is in fluid connection with the atmosphere via a venting channel. A sealing element is arranged in the venting channel. The sealing element cooperates with the venting channel to create a meandering pathway for air to pass through the venting channel so that leakage of lubricant between the sealing element and the venting channel is at least substantially prevented.

Abstract: A driver with a reverse-rotation preventer for an inflatable rotating exhibit is mounted inside an inflatable rotating exhibit having a transparent inflatable body and a rotating body and has a rotating assembly and a reverse-rotation preventer. The rotating assembly connects to and rotates the rotating body and has a synchronous motor that rotates in a direction and has a shaft. The shaft is driven by the synchronous motor and rotates the rotating body. However, the synchronous motor will reverse its rotation when the rotating body encounters even temporary resistance while rotating. The reverse-rotation preventer applies a resistance when the rotating body rotates in the wrong direction to make the synchronous motor reverse rotation. Consequently, the reverse-rotation preventer ensures that the rotating inflatable exhibit rotates in the desired direction.

Abstract: A driver for an inflatable rotating exhibit is mounted inside an inflatable rotating exhibit having a transparent inflatable body and a rotating body and has a rotating assembly and a reverse-rotation preventer. The rotating assembly connects to and rotates the rotating body, has a synchronous motor. The synchronous motor rotates in a direction and has a shaft. The shaft is driven by the synchronous motor and rotates the rotating body. However, the synchronous motor will reverse its rotation when the rotating body encounters even temporary resistance while rotating. The reverse-rotation preventer applies a resistance when the rotating body rotates in the wrong direction to make the synchronous motor reverse rotation again to the desired direction. So the reverse-rotation preventer ensures that the rotating inflatable exhibit rotates in the desired direction.

Abstract: The invention discloses a fluid-driven impactor, a power transmission mechanism for the impactor and the use of the impactor. In the prior art, the working life of the impactor is short, since a rubber primary seal and an upper fluid-diverging lid for the fluid-driven impactor are both liable to erosion and the efficiency in transmitting power is low due to the complexity of the power transmission mechanism. In order to increase the drilling speed and/or extend the life of the impactor, the side cavity passage is formed in such a way that the inner wall of the outer pipe is isolated from the side cavity passage in a watertight manner without the use of the rubber primary seal. The loss in transmitting power is minimized by integrating the anvil of the power transmission mechanism and the lower joint.

Abstract: A composite drilling tool comprises: a handle; and a driving portion installed at one end of the handle; the driving portion including a pneumatic portion, an electromotive portion, a coil and a battery; the pneumatic portion and the electromotive portion serving to drive the drilling rod through air power or electric power; the power of the electromotive portion being from the battery; the coil enclosing the drilling rod; when the drilling rod rotates, the magnetic flux from the magnetic unit will change so as to induce current in the coil and thus the battery is charged; and a drilling rod installed in the driving portion with a part being embedding into the driving portion and a part being protruded out of the driving portion for assembling a drilling head of various forms; and the drilling rod being installed with a magnetic unit.

Abstract: A hydraulic hammer having a sealing bushing includes a percussion piston that delivers strokes to a tool. A lower part of the percussion piston is sealed with respect to a frame by the sealing bushing, which includes one or more lower seals. The sealing bushing does not contribute to the bearing of the percussion piston and it is arranged in place through the lower end of the hydraulic hammer.

Abstract: An impact device includes a cylinder and a plunger which is received within the cylinder and movable in forward and rearward directions. The plunger includes a first and a second pressure receiving surface for receiving pressure of a pressurized fluid so as to apply force to the plunger in the forward and rearward directions, respectively. An additional pressure receiving surface is formed on the plunger for receiving the pressure from the pressurized fluid so as to apply force in the same direction as one of the first and second pressure receiving surfaces. A first control device is operable to selectively apply the pressure of the pressurized fluid to the additional pressure receiving surface.

Abstract: A starting arrangement for a reciprocating piston pneumatic hammer provides a passageway in the piston which couples a pneumatic piston subchamber to an exit port to exhaust pressurized pneumatic fluid from the subchamber to prevent the piston from centering.

Abstract: A tool for cutting percussive rotary drilling of boreholes includes a hollow casing having a bit. A hammer piston is installed in the casing for reciprocations and for cooperation with the bit for imparting impact impulses thereto. The hammer piston divides a working space of the casing into a workstroke chamber and a return stroke chamber which are alternately connected through distribution means provided in the casing with a source of a fluid under pressure for reciprocations of the hammer piston.

Abstract: A power control device for a pneumatic motor includes a pressure air supply flow limiting means in the form of a flow restriction having a diverging, pressure recovering outlet. The device also comprises a load responsive pressure relief means which is located downstream of the flow restriction and which is arranged to gradually release pressure air from the motor into the atmosphere in response to decreasing load applied on the motor. The device is effective in reducing the motor power in response to decreasing load upon the motor. The disclosed motor is a hammer piston impact tool, and the motor load responsive pressure release means comprises the forward end of the motor cylinder and passages on a thrust sleeve which receives the shank of a chisel and which is slidingly received in the cylinder.