Abstract: A piston for a hammer drill is a flat piston made from sintered steel. The piston can be impregnated with a lubricant.

Abstract: A power tool comprises a housing having at least two housing parts and at least one recess, a portion of the recess provided by each housing part, and a bearing located in the recess. The power tool includes a seal comprising an elongate seal member located between the housing parts to seal at least a portion of the housing. The seal includes at least one polymeric extension part extending from the elongate seal member and in contact with an external part of the bearing without extending around the bearing. The polymeric extension part of the seal prevents the external part of the bearing from rotating with respect to the housing during use of the power tool.

Abstract: A hammer drive mechanism is provided for converting rotary drive from a motor to reciprocatory movement of an impact member of a hammer drill. The mechanism comprises a rotatable plate adapted to be rotated by the motor, an input drive member associated with the rotatable plate in an eccentric position with respect to the axis of rotation of the rotatable plate, an output drive member associated with the impact member, and a crank shaft having a respective driver adjacent each of its ends. Each driver engages with, and is complementary to a respective one of the drive members. At least one end portion of the crank shaft comprises a lubricating aperture which opens into the adjacent driver to provide a lubrication path to the engaging surfaces of the drivers and the drive members.

Abstract: A hammer drill comprises a motor including an output shaft, a shaft assembly rotationally engaged therewith, a hollow spindle, and a hammer mechanism comprising a piston arranged for reciprocating motion within the spindle. The shaft assembly comprises a first part carrying a first gear engaged with a gear on the spindle to cause spindle rotation, a second part carrying a crank member to cause piston reciprocation, and a connecting part configured to rotationally interconnect, or disconnect, the first and second parts. In a first position of the connecting part only one of the first and second parts is rotationally engaged with the output shaft to enable rotation of only one of the first gear and the crank member respectively, while in a second position both the first and second parts are rotationally engaged with the output shaft to enable rotation of both the first gear and the crank member.

Abstract: A hammer drive mechanism is provided for converting rotary drive from a motor to reciprocatory movement of an impact member of a hammer drill. The mechanism comprises a rotatable plate adapted to be rotated by the motor, an input drive member associated with the rotatable plate in an eccentric position with respect to the axis of rotation of the rotatable plate, an output drive member associated with the impact member, and a crank shaft having a respective driver adjacent each of its ends. Each driver engages with, and is complementary to a respective one of the drive members. At least one end portion of the crank shaft comprises a lubricating aperture which opens into the adjacent driver to provide a lubrication path to the engaging surfaces of the drivers and the drive members.

Abstract: A power tool comprises a housing having at least two housing parts and at least one recess, a portion of the recess provided by each housing part, and a bearing located in the recess. The power tool includes a seal comprising an elongate seal member located between the housing parts to seal at least a portion of the housing. The seal includes at least one polymeric extension part extending from the elongate seal member and in contact with an external part of the bearing without extending around the bearing. The polymeric extension part of the seal prevents the external part of the bearing from rotating with respect to the housing during use of the power tool.

Abstract: A hammer drill comprises a motor including an output shaft, a shaft assembly rotationally engaged therewith, a hollow spindle, and a hammer mechanism comprising a piston arranged for reciprocating motion within the spindle. The shaft assembly comprises a first part carrying a first gear engaged with a gear on the spindle to cause spindle rotation, a second part carrying a crank member to cause piston reciprocation, and a connecting part configured to rotationally interconnect, or disconnect, the first and second parts. In a first position of the connecting part only one of the first and second parts is rotationally engaged with the output shaft to enable rotation of only one of the first gear and the crank member respectively, while in a second position both the first and second parts are rotationally engaged with the output shaft to enable rotation of both the first gear and the crank member.

Abstract: A switch assembly for a power tool including a switch member and a fixing part. The switch member including a finger grip part, a retaining part for retaining the switch member on a power tool, and an opening extending at least partially through the switch member, the retaining part arranged to project laterally with respect to an axis of the opening. The fixing part is arranged to be located in the opening. The switch assembly is arranged such that when the fixing part is at a first location in the opening, the retaining part adopts a retention configuration in which it projects laterally to a predetermined extent. When the fixing part is removed or at a second location in the opening, the retaining part adopts an insertion configuration in which it does not project laterally or projects less than the predetermined extent.

Abstract: A method of manufacturing a ram configured to be mounted for reciprocation in a guide tube section of a powered hammer. The ram includes an outer circumferential surface, a radially outwardly projecting sealing portion, and a helically shaped vent channel defined in the circumferential surface and running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. The method includes forming the outer circumferential surface of the ram and the helically shaped vent channel in a single manufacturing operation. For example, the method includes rotating a blank on a machine tool, forming the outer circumferential surface of the ram by applying a first machine tool bit to the blank while the blank is rotating, and forming the helically shaped vent channel in the outer circumferential surface by applying a second machine tool bit to the blank while the blank is rotating, without removing the blank from the machine tool.

Abstract: A switch assembly for a power tool comprises a switch member and a fixing part. The switch member comprises a finger grip part, a retaining part for retaining the switch member on a power tool, and an opening extending at least partially through the switch member, the retaining part arranged to project laterally with respect to an axis of the opening. The fixing part is arranged to be located in the opening. The switch assembly is arranged such that when the fixing part is at a first location in the opening, the retaining part adopts a retention configuration in which it projects laterally to a predetermined extent. When the fixing part is removed or at a second location in the opening, the retaining part adopts an insertion configuration in which it does not project laterally or projects less than the predetermined extent.

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: A method of manufacturing a ram configured to be mounted for reciprocation in a guide tube section of a powered hammer. The ram includes an outer circumferential surface, a radially outwardly projecting sealing portion, and a helically shaped vent channel defined in the circumferential surface and running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. The method includes forming the outer circumferential surface of the ram and the helically shaped vent channel in a single manufacturing operation. For example, the method includes rotating a blank on a machine tool, forming the outer circumferential surface of the ram by applying a first machine tool bit to the blank while the blank is rotating, and forming the helically shaped vent channel in the outer circumferential surface by applying a second machine tool bit to the blank while the blank is rotating, without removing the blank from the machine tool.

Abstract: A driving mechanism for a powered hammer having a motor and a tool holder includes a ram mounted for reciprocation in a guide tube section. The ram has a radially outwardly projecting sealing portion and an outer circumferential surface that defines a helically shaped vent channel running from a front end portion of the circumferential surface to a rear end portion of the circumferential surface and being interrupted by the sealing portion. A piston is driven in reciprocating motion of the motor such that an air cushion is generated in a space between the ram and the piston to cause an impact on the tool bit by movement of the ram towards the tool bit. The space between the ram and the piston is temporarily connected with ambient air through the helical vent channel and a recess in the wall of the guide tube section after causing the impact on the tool bit.

Abstract: A reciprocating drive mechanism for a striker in a hammer, a rotary hammer, or a power drill having a hammer action, includes a sinusoidal cam channel formed on a drive member and a cam follower, in the form of a ball bearing, attached to a driven member which, due to the interaction of the cam and cam follower, results in a reciprocating movement of the driven member. Both the drive member and driven member can be rotatingly driven by a motor, their relative speeds resulting in the reciprocating movement of the driven member. The driven member is connected to the striker either via a mechanical helical spring or an air spring.

Abstract: A tool holder (1) for a rotary hammer which has a tube like tool holder main body (10) having a side wall formed with through holes (11) for receiving corresponding locking bodies (12) and formed with additional through holes (40). The tool holder includes hardened metal driving ribs (46) each located on an insert (42) and the inserts are fitted within the additional through holes (40) so that the ribs extends axially and radially inwardly of the radially inward facing surface of the holder body. The locking bodies (12) are arranged to releaseably engage a corresponding axial closed groove of a tool or bit inserted within the tool holder and the ribs (46) are arranged to releaseably engaging a corresponding axial rearwardly open driving grooves of a tool or bit inserted within the tool holder.

Abstract: A tool holder for a power tool, in particular a drilling and/or hammering tool comprising a manually actuable sleeve (40) wherein components of the tool holder are held within the sleeve by a snap ring (100) which snap ring is fitted within the sleeve. The snap ring has at least one resilient arm (102) and the sleeve has a corresponding number of through holes (105) which extend to a radially outwardly facing surface of the sleeve, arranged such that the or each arm is engageable with a corresponding through hole in a snap fit. Each arm and through hole cooperate so that the portion (104) of the or each arm which can be viewed from the radially outwardly facing surface of the sleeve appears in the shape of a symbol. Thus, the snap ring (100) has the dual function of maintaining components, such as a locking ring (42) within the sleeve (40) and of providing an external indication to a user of how to actuate the sleeve.

Abstract: This patent relates to a method of assembling a spindle assembly comprising: a tubular spindle (2); a beat piece structure which is capable of being located and slid within a part (6) of the spindle (2); a stop mechanism (20) located within the spindle (2) which prevents the beat piece structure from sliding past it when the beat piece structure is located in and sliding within the spindle (2); and a retention mechanism capable of being located within the spindle (2) and which prevents the beat piece structure from sliding past it when the beat piece structure is located in and sliding within the spindle (2); wherein the method comprises the steps of: i) inserting the beat piece structure into the spindle through one end of the spindle and sliding it along the spindle (2) in one direction until it abuts the stop mechanism (20); ii) inserting the retention mechanism into the spindle through the same end of the spindle (2) until it locates at a predetermined position; iii) sliding the beat piece structure

Abstract: An electrically powered hammer is provided comprising a housing, a spindle, a hammering mechanism including a piston reciprocatingly mounted within the spindle, a wobble drive arrangement reciprocatingly connected to the piston, a trunnion arrangement including a cross bolt is driving engaged between the wobble drive arrangement and the piston, and wherein the piston includes a pair of piston arms and a protrusion so that the first piston arm and the protrusion define a first recess and the second piston arm and the protrusion define a second recess, and each of the recesses is shaped so as to support a wear reducing washer in an assembled position. When assembled each washer fits around the cross bolt in a region adjacent the inwardly facing face of the associated piston arm so as to reduce wear between the cross bolt and the piston arms.

Abstract: An electrically powered hammer is provided comprising a housing, a spindle, a hammering mechanism including a piston reciprocatingly mounted within the spindle, a wobble drive arrangement reciprocatingly connected to the piston, a trunnion arrangement including a cross bolt is driving engaged between the wobble drive arrangement and the piston, and wherein the piston includes a pair of piston arms and a protrusion so that the first piston arm and the protrusion define a first recess and the second piston arm and the protrusion define a second recess, and each of the recesses is shaped so as to support a wear reducing washer in an assembled position. When assembled each washer fits around the cross bolt in a region adjacent the inwardly facing face of the associated piston arm so as to reduce wear between the cross bolt and the piston arms.