Abstract: A driving tool having a striking unit and a driver unit includes a solenoid configured to switch between a first state and a second state by being actuated by the supply and stop of the electric power, wherein the driver unit has a first drive state in which the striking unit can be actuated and a second drive state in which the actuation of the striking unit is blocked, wherein the first state enables the driver unit to switch from the second drive state to the first drive state and the second state blocks the driver unit from switching from the second drive state to the first drive state, and wherein an actuation direction of the solenoid and the moving direction of the nail are arranged so as to intersect each other.

Abstract: A gas spring-powered fastener driver includes a cylinder, a moveable piston, a driver blade attached to the piston, the driver blade movable with the piston, a lifter including a rotary component operably coupled to the driver blade to move the driver blade from a driven position to a ready position, and a multi-stage planetary transmission. The transmission includes an output shaft operatively coupled to the lifter to provide torque thereto, a first bearing supporting a first portion of the output shaft for rotation, a second bearing supporting a second portion of the output shaft for rotation. The fastener driver also includes a housing having a cylinder support portion in which the cylinder is received and a transmission housing portion in which the first and second bearings are received to rotatably support the output shaft. The cylinder support portion and the transmission housing portion are integrally formed as a single piece.

Abstract: An apparatus and method for drilling is disclosed, including a drill string with at least one jar and one reaction valve. Drilling fluid flows through the reaction valve. The reaction valve is selectively throttled, which creates a differential pressure across the valve seat. The differential pressure creates an axial force that is transferred to the jar, which aids in cocking or firing the jar. In an embodiment, a reaction valve throttles downward fluid flow to create a downward compressional force on the jar, while in another embodiment, a reaction valve throttles upward fluid flow to create an upward tensile force on the jar. Upward and downward fluid flow may be alternatively throttled for alternately firing the jar upwards and downwards. A bypass valve may be included in the drill string for establishing a drilling fluid flow path when such may be otherwise obstructed by foreign matter in the wellbore.

Abstract: A powered hand-held fastening tool includes a housing defining a handle, a frame, a motor-driven flywheel journaled to the frame, and an elongated driver that is selectively coupled to the flywheel to drive a fastener into a workpiece. A follower assembly for selectively coupling the driver to the flywheel includes a solenoid actuator, a biasing mechanism, a lever arm connected between the solenoid actuator and the biasing mechanism, and an intermediate member having journaled thereto a pivot roller and a pinch roller. Upon energization of the solenoid the lever arm is moved in a direction parallel to the drive axis, thereby applying a force on the pivot roller perpendicular to the drive axis, causing the pinch roller to press the driver against the flywheel and initiate the drive stroke. The intermediate member pivots about the pivot roller to release the pressure on driver upon completion of the drive stroke.

Abstract: A down-the-hole drill hammer for optimizing air consumption. The down-the-hole drill hammer includes a housing, a backhead connected to the housing, and a pressure control check valve assembly mounted within the housing. The pressure control check valve assembly includes a first check valve and a second check valve. The first check valve controls a flow of working fluid through the backhead. The second check valve is mounted to the first check valve and controls a flow of working fluid through the first check valve.

Abstract: A die for a joining tool, in particular for clinching, with an anvil (4) forming the bottom (41) of a swage (50), and with a spring sleeve (3) which surrounds the anvil (4) and has a plurality of slits (32) extending in an axial direction (A), said slits (32) permitting a radial expansion of the spring sleeve (3), is characterized in that bushing (1) which is arranged between the anvil (4) and the spring sleeve (3) and which is provided, at its free end (17), with inserts (2) which surround the anvil (4) and are made of a harder material than the bushing (1).

Abstract: A flywheel-driven tool includes a ferromagnetic driver. The driver has a firing position in which the driver is drivingly engaged against the flywheel. The driver also has a home position radially further away from the flywheel than the firing position when the flywheel is spinning in preparation to firing the driver. A magnet is positioned adjacent the driver to exert a magnetic force on the driver to pull the driver into the home position.

Abstract: A tool has a mechanism for absorbing energy transmitted to a hand grip, comprising a support body, a handle, an elastic return member and an interchangeable head as a base unit which is capable of accommodating additional fittings depending on the specific application. A lower part of the cylindrical body has a shouldered part having a diameter larger than its upper part so as to allow positioning and support of a ring associated with the handle. The handle has an internal shouldered part with an upper face constituting the support for the elastic return member. The interchangeable striking head comprises a part centered in the ring and a neck that fits inside an internal bore of the body. The striking head rests directly on the body in order to transmit the entire striking force to the body, and the handle extends rearwardly as the hand grip.

Abstract: A percussive mechanism, which is provided in the form of an, e.g. pneumatic spring percussive mechanism, comprises an electrodynamic linear drive, a drive piston, which can be reciprocally moved inside a percussive mechanism housing by the linear drive, and a percussive piston. An additional hollow space is provided in front of and/or behind the drive piston and can be isolated at least in part from the surrounding area so that a pneumatic spring can be created in the additional hollow space. The pneumatic spring slows the drive piston at its returning points and facilitates a returning motion without loading the electrodynamic linear drive.

Abstract: A hand-held drive-in power tool for driving-in fastening elements includes a drive-in ram (13) displaceably arranged in a guide (12), a drive (30) for driving the drive-in ram (13) and having at least one driving spring member (31) for displacing the drive-in ram (13) and formed of a fiber-reinforced plastic material, and a device (70) for preloading the driving spring member (31).

Abstract: A nail gun includes a power coil for moving a plunger in two opposed directions. The plunger is first moved away from a nail, and force from this movement is stored in a force storage mechanism. The plunger is then driven by the coil in an opposed direction, and the force stored within the forced storage mechanism is released, such that the released force and the power force from the coil are combined to drive a nail into a work piece.

Abstract: Substantially cylindrical head tube body, center tube body and tip tube body threadedly engage each other to thereby construct a tool main body of a tool for wristwatch. The through hole of the center tube body is provided with a partition part having a small-diameter hole and slant face. A hammering member and compression spring are slidably accommodated in the through hole. A trigger shaft includes a small-diameter part which can be inserted in a center hole of the hammering member, and a large-diameter part continuing therefrom through the slant face, which can pass through the small-diameter hole. A deformed coil spring has the large-diameter part of the trigger shaft fitted therein in wound form, and energizes the trigger shaft toward sliding shaft while slanting the trigger shaft so as to cause the small-diameter part to shift toward the inside wall of the tool main body.

Abstract: A jackhammer system for reducing the vibration and noise experienced by an operator of the jackhammer. The jackhammer system includes a housing, a chisel movably positioned within a lower neck of the housing, a pair of flywheels rotatably attached to a pair of support brackets, a ram slidably positioned within a guide channel and engageable by the flywheels to engage the chisel, a plurality of elastic members attached to the ram, and an actuator mechanically connected to the support brackets for controlling a position of the flywheels. An upper sensor and a lower sensor determine the position of the ram within the guide channel. An engaging plate supported by a plurality of compression springs receives the downwardly impact of the ram when driving the chisel downwardly. A recoil absorber having a recoil spring is attached to an upper portion of the housing for absorbing the recoil of the ram.

Abstract: An attachment for an impact hammer for translating the hammer's typical forwardly directed impact force into a rearwardly directed pulling force while still allowing the user to maintain a conventional orientation of the hammer relative to the work piece intended to be pulled. The attachment comprises a housing defining a cavity with a hammer bit axially movable therein and having an impacting head urged rearwardly by a bias structure which responds to a forward impact force by the impact hammer to cause the hammer bit head to exert impact force on the work piece in a rearward direction.

Abstract: An impact tool driver includes a hollow holding member having a surrounding wall defining a chamber. A solid and rigid shank of a handle is formed with a V-shaped cam hole, and extends into the chamber such that the V-shaped cam hole is registered with two diametrically disposed pin holes in the surrounding wall. A compression spring is disposed within the chamber in the holding member, and abuts against the shank and the holding member. A pin extends through the pin holes in the surrounding wall and the cam hole in the handle, and slidably contacts a cam face that defines the cam hole.

Abstract: Screwdriver for operating self-tightening screw, including a grip; a striking mechanism disposed in the grip for providing a striking force; and a stem body slidably disposed in the grip. The top end of the stem body is drivingly engaged with the striking mechanism. The bottom end of the stem body serves to drive the self-tightening screw. In use, the screwdriver is pressed downward against the self-tightening screw. At this time, the stem body is slided into the grip to drivingly move the striking mechanism. The striking mechanism produces a striking force acting on the self-tightening screw so as to nail the self-tightening screw into a screwing position of a work piece. Then the screwdriver is used to screw the self-tightening screw into the work piece.

Abstract: A compressed-air-operated percussion mechanism includes a housing, a percussion body and a balancing body, which form an operating chamber therebetween. A secondary valve seals the operating chamber during an operating stroke and opens the chamber to evacuate compressed air after the termination of the operating stroke. A primary valve is connected to the compressed air inlet passage and intermittently opens to provide compressed air to the operating chamber.

Abstract: Apparatus for applying additional momentum to the movement of a body adapted to reciprocate or flex through a substantially linear or arcuate path, notably of increasing the impact velocity of a linearly travelling weight upon an object. The apparatus includes an element for retracting the body from its rest position, notably for retracting a weight from the point of impact between the weight and an object located at the rest position of the weight and an element for biasing the body towards its rest position, notably for urging the weight towards the object so as to impart additional impact velocity to the weight as it travels toward the object. The apparatus is characterized in that: a) the element for biasing the body towards its rest position is an elastic polymeric material which is retained under tension or compression when the body is in its rest position; and b) the biasing element is one which undergoes strain crystallization. Also a method for breaking or penetrating a surface using the apparatus.

Abstract: Pressure fluid operated impact mechanism having a reciprocating working member (5), a stop member (17) and, formed between said members, a drive chamber (18) with seals (15, 16) and a regulating valve (21) co-operating with a supply opening (25) for pressure fluid, in which opening a sleeve (24) can be arranged for the journalling of the valve. The valve blocks the opening when the working member (5) and the stop member (17) have moved a distance away from each other and is open when they are close to each other. Through the valve and the working member, a discharge channel (33, 31, 20, 32) for pressure fluid is provided which is closed when its inlet opening (33) is inside the stop member and is freed when the working and stop members have moved a distance away from each other.

Abstract: A pressure medium operated reciprocating impact mechanism has at least one working member (7) and at least one stop member (15), which are axially movable with respect to each other, and a working chamber (22) for pressure medium is arranged in at least one of them and is opened towards the other member. One of the members has an opening (39) emerging into the working chamber for feeding pressure medium to the working chamber. The impact mechanism comprises an arrangement (21) for sealing the working chamber in the position in which the members are brought most together and allow pressure medium to escape out of the working chamber when a predetermined relative position of the members is reached during their movement apart.

Abstract: A manually operated tool for chipping material from a surface includes a plurality of axially extending needle-type chisels (8) located within a housing (1) and guided in a needle cage (12) positioned within the housing. The needle cage (12) is freely axially displaceable between a stop shoulder (15b) of a guide sleeve (14) and an anvil (17) both of which are axially displaceable within the housing. The guide sleeve (14) is pressed by a compression spring (16) against the anvil (17).

Abstract: An automatic screwdriver is capable of generating an impact force on a screw that is being tightened or loosened. An action rod is disposed eccentrically in conjunction with a short helical spring. The eccentric position of the action rod is corrected by engagement with an annular flange within the main body of the handle upon rearward movement thereof which causes movement of the action rod into a slot in an impact rod resulting in an impact force which is imparted to a head tip.

Abstract: An electromechanical tool for driving fasteners into a workpiece. The tool uses a single flywheel in combination with a clutch mechanism whereby a conically shaped flywheel frictionally cooperates with a corresponding drum to cause a driver which is coupled to the drum by a cable to be pulled with considerable force through a working stroke to drive a fastener from the tool.

Abstract: A lightweight fastener driving tool capable of being battery powered utilizes a low cost fastener driving ram or blade that is normally located in a nip defined between a motor driven flywheel and an idler wheel. Upon the actuation of a trigger operated timing circuit, a solenoid is energized. The solenoid controls a toggle mechanism to adjust the position of the idler wheel with respect to the flywheel so as to force the blade against the flywheel and thereby to close the nip for a sufficient amount of time to initiate the driving of the blade downwardly through the nip. The timing circuit deenergizes the solenoid prior to the time that the blade exits the nip but the toggle mechanism maintains the idler wheel against the blade such that the blade continues to be driven by the flywheel. When the top of the blade exits the nip, the idler wheel can move towards the flywheel and the toggle mechanism releases the idler wheel so that the nip is open.

Abstract: A tool 10 for creating a standard repeatable impact on a nuclear steam supply system (NSSS) structure to determine the response of an accelerometer to the impact of a known energy at a predetermined location on the structure. The tool 10 includes a barrel 12 and a spring 30 which biases a ram 20 reciprocally mounted in the barrel and driven by cam plates 66 and 68 on shaft 60. A flange 28 on ram 20 compresses spring 30 and upon movement of follower 72 to a maximum radial distance from shaft 60, the follower 72 drops down step 70 on the cam surface to allow spring 30 to uncompress and project ram 20 out of the barrel such that end 22 of the ram creates a standard impact on the NSSS structure. A hand crank drives shaft 60. A dampening spring 78 assists in the rebound of the ram 20.

Abstract: An impact power tool for use in delicate hand-working operations includes a body presenting a bore and a piston received within the bore and shiftable relative thereto. An impact transmitting member is also received in the bore and is shiftable relative to the body. This impact transmitting member is positioned axially in the bore by a mounting element interposed between the impact transmitting member and the body, the mounting element being resilient relative to the body. The piston is driven along a stroke length between an impact position engaging the impact transmitting member and an extended position out of contact with the member.

Abstract: A single-stroke pneumatic apparatus incorporates a hollow cylindrical frame 1) with inlet and outlet ports (2,3). A handgrip (4) containing a directional flow control (5) is attached to the upper end of the frame. A striker (6) is provided in the bore of the frame (1) with provision for reciprocating back and forth so as to divide this bore into a forward-stroke chamber (8) a back-stroke chamber (7). A tool (9) is supported in the lower end of the frame (1). A shell (10) with holes (11) surrounds the frame (1) from the outside, forming a muffling chamber (12) therewith, within a full length of the stroke of the striker (6). Additional outlet ports (15) are provided in the lower end of the frame (1) which communicate the back-stroke chamber (8) with the muffling chamber (12) located wherein is a filter (6) overlapping the holes (11) in the shell (10).

Abstract: A single-blow pneumatic percussive tool includes a hollow cylindrical casing (1) having inlet and outlet ports (2, 3). A hammer piston (4) mounted in the casing (1) divides the interior space of the casing (1) into lower and upper chambers (5,6). A working tool (7) is mounted in the casing (1) on the side of the lower chamber (5). A handle (9) having passages and an air distribution device (8) is mounted in the upper part of the casing (1). A sleeve (12) with ports (13) is mounted on the casing (1) to define a space (14) therewith. An air distribution sleeve (15) is axially biased by a spring mounted in the space (14). The outlet ports (3) of the casing (1) are aligned with the ports (13) of the sleeve (12). The air distribution sleeve (15) has radial ports and recesses (17) which are aligned with the radial ports ( 16) on both surfaces of the air distribution sleeve (15). At least one passage (18) is made in the hammer piston (47) which is biased by spring on the side of the lower chamber (5).

Abstract: A portable vacuum pump for desoldering applications has a hollow cylindrical barrel forming a vacuum cylinder containing a plunger. The pump has a trigger housing containing a single compression spring. The spring is mounted outside the barrel. No separate return spring is required to hold the trigger in the latched position. The single trigger keeps the spring end out of the barrel and thus out of contact with the soldering debris. This allows more space for the plunger, producing a longer stroke and a higher vacuum.

Abstract: A hand-held pneumatic rescue tool may be driven from a bottled compressed gas. The driving gas is used only for the blow-striking stroke, while a compression spring is used to provide a force for the return stroke that is independent of the pressure of the driving gas. Thus, the pressure of the driving gas may be varied to adjust the impact force of the blows struck, without adversely affecting operation of the tool. By appropriate valving, the tool will operate continuously and automatically so long as driving gas is supplied, as determined by the operator.

Abstract: A high impact device, as for producing an impact of 1,000 foot pounds or more, includes a ram which is engageable by a pair of rotating flywheels. The ram may impact a tool, as of a chisel type adapted for demolition purposes, or having a enlarged head for percussion purposes, or other types or purposes. By terminating the engagement of the flywheels with the ram prior to its impact against a tool or similar object, the vibration normally associated with a demolition or percussion device is avoided. Such termination of engagement also reduces reverse shocks and conserves the energy of the rotating flywheels. In one embodiment, the flywheels are moved inwardly and outwardly of the ram through a linkage connected to a solenoid, with each flywheel supported between a pair of arms and alignment of the axis of each flywheel with the side of the corresponding ram being maintained by a torque tube extending between the arms.

Abstract: A motor-driven hammer may include an air motor, a DC motor operated from rechargeable batteries, or an AC motor operated from the commerical power supply. In one embodiment, the motor is coupled to reciprocate the hammer head by way of a cam is a tension spring. In the second embodiment a compression spring is employed in conjunction with a cam which releases the hammer head upon full compression of the spring.

Abstract: A fastener driving tool is provided which employs a drive housing subassembly, preferably in the form of opposed cast metal housing sections, which encloses the flywheel and suitable bearings for rotating the same at high speed. This subassembly also supports the associated idler wheel positioned on the other side of the fastener driving ram from the flywheel and mounts a toggle mechanism for adjusting the idler wheel from an inoperative position, in which the idler is spaced a substantial distance away from the ram, to an operative position close to the ram in response to movement of the tool into engagement with a workpiece. The drive housing subassembly also provides a top opening recess or well which is adapted to receive and position a removable cartridge which includes the ram and an elastic cord return mechanism, this subassembly also defining a vertically extending slot communicating with said recess which is adapted to receive the vertically positioned ram between the opposed flywheel and idler.

Abstract: An impact power tool for delicate hand working operations is provided which is especially adapted for detailed engraving, carving, and delicate stone setting applications. The power tool preferably includes a hand-held impact device, a piston received within the body of the device and shiftable therein for delivering impact energy to the device, conduit for delivering and venting motive fluid from and to the hand-held device for shifting of the piston, and a valve coupling the directing and venting conduits to the device in alternative fashion at rapid, variable, cyclical rate. The impact tool may be operated by connection to a standard source of pressurized air. The tool is capable of providing a greater range of impact strokes per second than conventional hand-held controlled impact tools, and thereby provides expanded capability for extremely delicate and fine engraving, carving and stone setting work.

Abstract: In an electromagnetically operated driving tool, in which a cup-shaped plunger carrying a driver blade is axially slidable in a solenoid, an air damper, combined with a check valve, is provided to damp the plunger during its backward movement to an inoperative position. A hollow cylinder positioned in the plunger is vented through an opening in a housing of the tool and has an interior which is closed at its end with a liftable valve flap. A throttle gap is formed between the plunger and the cylinder, which is adjustable by a piston movable in the cylinder which is made of elastic plastics and is elastically expandable to vary the throttle gap.

Abstract: An electrically-operated multi-needle chisel tool including a housing having a front portion and a rear portion. An electric motor is mounted in the rear portion. A cylinder extends forwardly from the front portion of the housing. A piston is disposed in said cylinder for reciprocable linear motion which is converted from the rotary motion of the motor. An anvil is axially slidably supported in the cylinder and positioned forward of the piston so as to be hit by the piston. A needle supporter is axially slidably supported in the cylinder and positioned forward of the anvil so as to be hit by the anvil. A number of needle chisels are individually supported by the needle supporter for axially slidable movement, and a return spring disposed in the cylinder for returning the needle supporter, the piston, the anvil and the needle supporter being adapted to be synchronously reciprocated by the motor. The piston includes a base portion and a reduced diameter shaft portion extending forwardly from the base portion.

Abstract: A pair of rotating flywheels which engage a ram for moving a tool which impacts a part, such as a nail to be driven, are rotated in opposite directions from a single motor or other rotating means, through a pair of substantially identical gears, one of which drives one flywheel and the other of which drives the other flywheel. The drive connection between the respective gears and each of the flywheels may include a belt and pulley arrangement, so that each flywheel may be driven directly by the respective belt but the flywheels are pivoted toward and away from the ram so that when the flywheel moves toward the corresponding side of the ram, the connection between the belt and the corresponding pulley will tend to slacken. A special flywheel pulley has an inner V-shaped groove and parallel side walls for guiding the belt into the groove when full tension occurs.

Abstract: A power operated percussion tool in which a shoulder (28) in the tool housing (10, 17) defines a rear rest position for working implement (12) attached to the tool, and in which an energy absorbing bias unit (23, 31) is arranged to resiliently load the working implement (12) toward the rest position. The bias unit (23, 31) comprises a spring (23) and a shock wave mitigating ring assembly (31) and acts between a rearwardly facing shoulder (22) in the housing (10, 17) and a forwardly facing shoulder (30) on the working implement (12). The ring assembly (31) includes two spring steel rings (32, 33) formed with mating conical contact surfaces for transforming axial load variations into radial deformation of the rings (32, 33).

Abstract: To prevent bounce of a hammer or plunger element coupled to an insertion blade of a stapling or nailing gun upon return of the plunger element to rest position by a spring (11), the plunger element (4) is in cup shape, sliding about a hollow cylinder (6) which is vented to ambient air (8) at one end, but closed at its other end by a flap-type check valve (9).

Abstract: A ram head for self-driven pneumatic ram drills for producing boreholes in the earth, having a generally tubular housing within which there is movable axially back and forth an impact piston whose impact energy can be transmitted to the ram head arranged at the front end of the housing. In order on the one hand, to crush obstacles by high energy and, on the other hand, to avoid too strong a compacting of small particles of earth in front of the apparatus and in addition make it possible to drive pipes, the generally conical ram head is provided with a central axial bore within which an impact bolt is mounted for longitudinal displacement between two end positions which are limited by stops, at the front end position of which supported by a spring the impingement surface of the impact bolt for the impact piston lies within the anvil surface of the ram head and at the rear end position of which the impingement surface projects from the anvil surface in the direction towards the impact piston.

Abstract: One or both of a pair of oppositely rotating bodies, such as motor driven flywheels, are mounted for pivotal movement against the side of a ram. One or more tension rods connect pivot shafts or members for equalizing precession and similar forces of rotating bodies, rather than housing. Pulsed solenoids produce force increased by force multiplying device, such as pivoted links or cable arrangement, which has greatest mechanical advantage when solenoid pull is weakest at start, but decreases as solenoid pull increases. Ram has entrance taper on one or both sides. Ram is returned by nylon sheathed bundle of elastomer cords which are looped around ram from both sides and stretch proportionally along their length. Removable guide rods engage holes in side wings of ram. Safety device is actuated by rod, moved through engagement with work piece, for closing safety switch in solenoid circuit. Alternatively, a block engages a ram wing to prevent impact stroke, but is removed by a similar rod.

Abstract: An impacting device useful with a pneumatic drive comprises a housing formed with an outer large-diameter bore and an inner small-diameter bore defining an annular shoulder at their juncture. A driving element within the large-diameter bore is limited against movement by the annular shoulder. A plunger movable within both bores is urged by a spring into the large-diameter bore in engagement with the driving element and carries an impacting element, such as a ball, at its opposite end. A air-vent formed through the housing wall is in communication with the first bore at a location so as to be on the inner side of the driving element when the latter is in its initial position, and at the opposite side of the driving element when the latter has been driven by pressurized air pulses to limit against the annular shoulder. Thereafter the plunger continues moving, under its own inertia, to cause the impacting element at the outer end of the plunger to engage the workpiece.

Abstract: A device for driving a tool with a reciprocating motion utilizing a rotary electric or pneumatic hand drill as a power source. The device includes a main shaft adapted to be held in a three-jaw chuck of a hand drill and having a concentric sleeve-like rear eccentric attached thereto. The shaft is arranged to rotate in a bearing in a handle frame. A forward sleeve-like eccentric is disposed on the forward end of the main shaft and adapted to slide forward and backward on the main shaft, and on a guide rod parallel to the main shaft, having a compression spring and attached to the handle frame. The front end of the forward eccentric is internally threaded to accept a tool-holding chuck. In operation, the main shaft is attached to a power hand drill which rotates the shaft. The rear eccentric rotates against the forward eccentric causing it to reciprocate and drive a tool held in a front chuck.

Abstract: A single impact rivet gun has a piston freely movable within a cylinder that is surrounded by an air accumulator. A valve to control flow of the air from the accumulator to the inside of the cylinder is located at one end of the cylinder and the valve has an opening leading from outside the gun to the inside of the cylinder. The gun includes means for introducing a vacuum at the opening to pull the piston to a starting position.

Abstract: This invention relates to an electric impact tool characterized by a pair of electric motor-driven counterrotating flywheels, at least one of which is movable relative to the other from a retracted inoperative position into an extended operative one closely adjacent the other flywheel whereby a ram is squeezed therebetween and impelled forward at high speed against a workpiece. The nosepiece of the tool frame is retractable although normally extended due to the spring bias urging it and the movable flywheel to which it is mechanically linked into disengaged position. These elements cooperate with one another and with a manually-actuated trigger such that the latter must be depressed and the nosepiece retracted in order to engage the high energy friction clutch defined by the flywheels so as to operate the ram. A flywheel speed control is provided for matching the ram impact to the workload.

Abstract: A power tool having a cylindrical housing accomodating a hammer and a two-step defining piston head, with central, rear and supplementary chambers in the housing, said head and supplementary chambers being constantly intercommunicated through a passage provided in the housing. The design of the power tool is aimed at minimizing vibrations of the housing and reduction of the forces applied to the handle during normal operation of the power tool.

Abstract: A method for damping the movement of the hammer piston of a hammer mechanism and for catching the hammer piston in a forward end position when the drill tool is situated outside the operating range of the hammer piston is disclosed. During the return stroke of the hammer piston gas is driven from one chamber to another chamber through a slot. When the hammer piston exceeds its normal range of operation gas is driven through the slot in the other direction and also through a channel in the machine housing so that a weaker damping is obtained than during the return stroke. A hammer mechanism to be operated according to the above method is also disclosed.