Abstract: A pneumatic device includes a casing unit defining a first chamber, a receiving space and a front space; a cylinder movably received in the receiving space, defining a second chamber and a releasing room, and having an air passage unit and an annular groove; and a hollow piston rod in sliding engagement with the cylinder, and having an inlet channel, a communicating room and an air hole unit. The cylinder and the piston rod are movable to change between a pneumatic state, where the air hole unit is communicated with the inlet channel, the annular groove, the communicating room and the second chamber, and an air discharging state, where the air passage unit is communicated with the second chamber, the receiving space and the releasing room.

Abstract: A pneumatic device includes a casing unit defining a first chamber, a receiving space and a front space; a cylinder movably received in the receiving space, defining a second chamber and a releasing room, and having an air passage unit and an annular groove; and a hollow piston rod in sliding engagement with the cylinder, and having an inlet channel, a communicating room and an air hole unit. The cylinder and the piston rod are movable to change between a pneumatic state, where the air hole unit is communicated with the inlet channel, the annular groove, the communicating room and the second chamber, and an air discharging state, where the air passage unit is communicated with the second chamber, the receiving space and the releasing room.

Abstract: A handle device for a hammer gun includes a tubular sleeve and a handle body. The tubular sleeve is adapted to connect threadedly with a barrel of the hammer gun, and includes front and rear end faces, a peripheral wall interconnecting the front and rear end faces, an installing cavity extending from the front end face toward the rear end face and adapted to receive therein the barrel of the hammer gun, and a retaining portion provided on the peripheral wall. The handle body has a grip portion, and a casing portion molded directly over the tubular sleeve and engaging the retaining portion so that the tubular sleeve is connected immovably to the handle body.

Abstract: A pneumatic hammer drill includes a handle body, a pneumatic cylinder, a piston, a tool, and a damping member. The handle body has an upper part that defines a front cavity and that has a rear end. The pneumatic cylinder has a cylinder rear end fitted in the front cavity, a front tool-connecting end, and a pressure chamber. The piston is disposed slidably in the pressure chamber. The tool is inserted into the pressure chamber through the front tool-connecting end. The damping member is made of a vibration-damping material, and is attached to the rear end of the handle body.

Abstract: A pneumatic hammer drill includes: a pneumatic cylinder having a cylinder rear end fitted in a handle body, an air passage, and a pressure chamber; and an air valve adjacent to the cylinder rear end. The air valve has a front bearing end, a valve orifice interconnecting fluidly the air passage and the pressure chamber, and an opening disposed at the front bearing end in communication with the valve orifice. A piston is disposed slidably in the pressure chamber, and has a piston rear end capable of moving towards or away from the front bearing end. An air trap arrangement is associated with the piston rear end and the front bearing end to trap air between the same and around the opening so as to provide a shock-absorbing air cushion when the piston rear end moves towards the front bearing end.

Abstract: A handle device for a hammer gun includes a tubular sleeve and a handle body. The tubular sleeve is adapted to connect threadedly with a barrel of the hammer gun, and includes front and rear end faces, a peripheral wall interconnecting the front and rear end faces, an installing cavity extending from the front end face toward the rear end face and adapted to receive therein the barrel of the hammer gun, and a retaining portion provided on the peripheral wall. The handle body has a grip portion, and a casing portion molded directly over the tubular sleeve and engaging the retaining portion so that the tubular sleeve is connected immovably to the handle body.

Abstract: A pneumatic hammer drill includes a tool connected to a pneumatic cylinder having an air valve assembly, return- and forward-stroke chambers, a piston, and a connecting passage interconnecting fluidly the return- and forward-stroke chambers. When the piston approaches the tool, the connecting passage permits air to flow from the return- to the forward-stroke chamber so that the pressure in the return-stroke chamber is reduced, and the speed of a forward stroke of the piston is increased. When the piston approaches the air valve assembly, the connecting passage permits air to flow from the forward- to the return-stroke chamber so as to reduce the pressure in the forward-stroke chamber so that the piston moves close to the air valve assembly during a return stroke thereof and the length of the forward stroke is increased.

Abstract: A pneumatic hammer drill includes a handle body, a pneumatic cylinder, a piston, a tool, and a damping member. The handle body has an upper part that defines a front cavity and that has a rear end. The pneumatic cylinder has a cylinder rear end fitted in the front cavity, a front tool-connecting end, and a pressure chamber. The piston is disposed slidably in the pressure chamber. The tool is inserted into the pressure chamber through the front tool-connecting end. The damping member is made of a vibration-damping material, and is attached to the rear end of the handle body.

Abstract: A pneumatic hammer drill includes a handle body, a pneumatic cylinder, a piston, and a shock-absorbing sleeve. The pneumatic cylinder has a cylinder rear end fitted in the handle body, a front tool-connecting end, and a pressure chamber. The piston is disposed slidably in the pressure chamber. A tool is inserted into the pressure chamber through the front tool-connecting end. A spring element is attached to the front tool-connecting end, and has a spring end connected to the tool for pulling the same rearwardly. The shock-absorbing sleeve is made of a resilient material, is inserted into the front tool-connecting end around the tool, and has a front end to abut against the tool when the tool is pulled rearwardly.

Abstract: A pneumatic hammer drill includes: a pneumatic cylinder having a cylinder rear end fitted in a handle body, an air passage, and a pressure chamber; and an air valve adjacent to the cylinder rear end. The air valve has a front bearing end, a valve orifice interconnecting fluidly the air passage and the pressure chamber, and an opening disposed at the front bearing end in communication with the valve orifice. A piston is disposed slidably in the pressure chamber, and has a piston rear end capable of moving towards or away from the front bearing end. An air trap arrangement is associated with the piston rear end and the front bearing end to trap air between the same and around the opening so as to provide a shock-absorbing air cushion when the piston rear end moves towards the front bearing end.