Abstract: A pneumatic hammer mechanism is disclosed. The hammer mechanism features: a flying mass, which is movable along an impact axis; an impact surface, which limits a movement of the flying mass along the impact axis in the impact direction; an exciting piston, which limits a movement of the flying mass along the impact axis opposite from the impact direction; a pneumatic chamber between the flying mass and exciting piston; and a drive for periodically moving the exciting piston with a stroke along the impact axis. The flying mass is excited to a periodic movement between the impact surface and a minimum approach of the exciting piston. A length ratio of the maximum length of the pneumatic chamber to the stroke is selected as less than 1.55.

Abstract: A cylindrical, protective housing and accompanying insertion tool for shielding an in-ground sprinkler head. The cylindrical housing is inserted into the ground surrounding an in-ground sprinkler head, protecting the sprinkler head and subterranean feed lines from damage resulting from yard work or other traffic. The cylindrical housing prevents inadvertently sprinkler head collisions with lawn mowers, wheelbarrows, golf carts, or similarly wheeled vehicles. The insertion tool is a male-fitting press tool that provides vertical loads on the cylindrical housing upper extent to force it into soil surrounding a sprinkler head.

Abstract: A plurality of weight hammers (7,8) are provided, and each of the plurality of weight hammers has a shape for substantially evenly applying a hammering force with respect to a surface to be hammered of an object to be hammered (11), about a center line of the object to be hammered. Rotors (9, 10) for driving the weight hammers (7,8) are provided to the same rotating shaft (22) in such a positional relation that an engagement claw (9a) of one rotor (9) engages and drives one weight hammer (7), and, when engagement of the weight hammer (7) is released, an engagement claw (10a) of another rotor (10) in driving engages another weight hammer (8). The rotors are driven by the same driving means (26).

Abstract: A hammer drill has an elastic member without using a coil spring or the like on an intermediate spindle to compact a housing and decrease cost. The elastic member that elastically engages a clutch with a second gear and/or a boss sleeve includes first to third guide spindles, first and second interlock plates, and a coil spring. The guide spindles are provided in parallel with an intermediate spindle. The first and second interlock plates are provided at the first to third guide spindles and slidable integrally with the clutch by engaging with the clutch. The coil spring energizes the first and second interlock plates along the first to third guide spindles.

Abstract: A powered hammer includes a housing, a tool holder coupled to the housing and configured to hold a tool, a motor within the housing, a piston slideably mounted within the housing, a drive mechanism that converts rotary output of the motor into a reciprocating motion of the piston, a ram slideably mounted forward of the piston and that is reciprocatingly driven by the piston, and a beat piece support mounted in the housing forward of the ram. A beat piece is slideably supported by the beat piece support. The beat piece is repetitively struck by the ram and that in turn repetitively strikes an end of a tool when the tool is held in the tool holder to transfer the momentum of the ram to a tool. The beat piece support includes a seal that is slidingly engaged by the beat piece. The seal includes an absorbent material.

Abstract: Self drilling anchors and related methods and apparatus. In one embodiment an apparatus comprises a drill bit, a hammer mechanism for hammering the drill bit in a first direction and in a second direction, and a selection mechanism for controlling whether, at a given point in time, the drill bit is hammered in the first or second direction.

Abstract: In order to avoid the recoil of the striker in a hammer device (tool machine) with a striker (18) that can be accelerated to strike velocity, and a tool carrier (14) receiving the impact of said striker, the invention proposes to arrange the striker (18) between the tool carrier (14) and a corresponding mass carrier (16) which moves together with the striker (18) until the striker (18) strikes the tool carrier (14), imparting its own momentum via the striker to the tool carrier, with a supplementary mass (56) on the mass carrier (16) providing the necessary striking energy.

Abstract: An impact motor comprises a housing (10) with a cylinder (11) therein, in which a reciprocating drive piston (40) via a gas cushion in a working chamber (44) of said cylinder (11) repeatedly drives a hammer piston (15) to impact on and to return from the neck (17) of a tool (20) carried by the machine housing (10). A piston groove (68) is provided adjacent to the front face (70) of the drive piston (40) and the peripheral part of said face (70) is rounded (71) towards said groove (68). A piston ring (41) is of steel having a temperature expansion coefficient substantially equal to the cylinder's (11) and is ground circumferentially to have a close sliding and sealing fit in the cylinder (11). The rounded (71) drive piston face (70) is adapted to the inner diameter of said ring (41) so as to permit the ring (41) to be forced into said groove (68) undeformed to ride on a elastically centering O-ring (69) of heat resistant rubber.

Abstract: This invention pertains to a hydraulic reciprocating device having a housing and a piston in the housing. The piston has a first and second surface, and a means for intermittently communicating the first surface of the piston with a hydraulic pressure source. Also provided is a means for continuously communicating the second surface of the piston with pressurized fluid such as pneumatic fluid. The piston moves in a first direction when the hydraulic pressure source communicates with the first surface of the piston and the piston moves in a second direction when the hydraulic pressure source does not communicate with the first surface of the piston.

Abstract: Two elongated members are coaxially movable relative to one another with one member rigidly attached to a working head such as an elongated wedge or the like. In one embodiment, the inner member is fixed to the working head while the outer member movably surrounds the inner member. The outer member is dimensioned so that its lower perimeter edge is small enough to allow the members to be reciprocated so as to drive the head into a log or other material without the outer member being held against coaxial reciprocal movement by the material. The members can be secured as for lifting, withdrawing, transporting, and the like with a flexible collar on the outer member for cooperating with a hole therethrough for gripping the inner member. The outer member can be fixed to the working head and the inner member reciprocally movable therein. Shock absorbing handles and an impact surface cushion insert are also shown which reduce jarring and fatigue in an operator's hands and arms.

Abstract: Two elongated members are coaxially moveable relative to one another with one member rigidly attached to a working head such as an elongated wedge or the like. In one embodiment, the inner member is fixed to the working head while the outer member moveably surrounds the inner member. The outer member is dimensioned so that its lower perimeter edge is small enough to allow the members to be reciprocated so as to drive the head into a log or other material without the outer member being held against coaxial reciprocal movement by the material. The members can be secured as for lifting, withdrawing, transporting, etc., with a particularly advantageous form of the securing means being a flexible collar on the outer member for cooperating with a hole therethrough for gripping the inner member. The outer member can be fixed to the working head and the inner member reciprocally moveable therein.