Abstract: A percussive tool has a percussion mechanism driven by a linkage that combines the simplicity of a connecting rod drive with the compactness of more complex drives. A first member, which may be a crank, drives a second member, which may be a cylinder, mounted for sliding and pivotal movement in a guide. A piston is mounted for reciprocating movement in the cylinder. Rotation of the crank reciprocates the piston causing blows to be imparted to a tool piece. The tool piece is rotated as well as being subjected to percussion.

Abstract: A turf scarifier and raker includes a housing with an elongated upright handle and having suitably positioned wheels designed to permit traversing movements over turf while the operator is in a standing position. The housing has an electric motor positioned in essentially the same plane as a tine assembly driven by the electric motor. The tine assembly has a plurality of tines which extend through an opening at the bottom of the housing. The tines result from a plurality of torsion coil springs having radially extending active ends that are serially threaded on rods arcuately and radially located about a central axle of the tine assembly. The active ends come into contact with the turf when the device is operated. At the same time, the other ends of the springs are inhibited from turning torque, preferably by lying in abutment against the central axle.

Abstract: A portable electric tool with a housing having a motor compartment and a pistol grip handle is provided with a trigger-switch, incorporating a motor reversing switch, mounted in the handle. An elongated lever is pivoted intermediate its length and contained within the housing. The rear end of the lever is connected to the reversing switch for actuation thereof. The forward end of the lever has a downwardly projecting protrusion which engages in a slide member which is slidable along an arcuate slot in the lower wall of the motor compartment for pivoting the lever. Intermediate the forward end of the lever and the pivotal axis of the lever is a downwardly projecting pin which coacts with a partition and two grooves in the upper part of the trigger-switch to block the movement of the trigger until the lever has been pivoted to actuate the reversing switch, and also to prevent pivoting of the lever while the trigger is in an inward position energizing the tool.

Abstract: In a portable tool, the electric motor is mounted within the tool and motor housing, of heat softening polymeric material, by spacer members of heat resistant polymeric material.

Abstract: A filament type vegetation trimmer having slinger head for rotating a portion of the filament in a radial plane is provided with a filament support tube for supporting the filament in the radial plane, the filament support tube being provided with apparatus which coact with apparatus provided in the slinger head for cooling the filament supported therewithin.

Abstract: A depth of cut adjustment mechanism for a power planer including a double threaded elevation adjustment bolt (40) extending downwardly into threaded engagement with a stem (32) extending upwardly from the front shoe (16) of the planer (2). Rotation of the bolt (40) is controlled by a knob (20) attached to the head portion (54) of the bolt (40). The knob (20) has associated therewith a scale (41) which is readily calibrated so that a zero reading on the scale corresponds to a zero depth of cut. The adjustment mechanism further provides a positively located park position wherein the front shoe (16) is extended downwardly beyond the cutting blade (8) to effectively elevate the cutting blade (8) so that it does not mar the surface upon which the planar (2) is set when not in use.

Abstract: A shut-off device (104) controlling the operation of the motive means such as an electric motor which powers a tool such as a chain saw (12) having a housing (14) with a brake (34) therein operative to stop the chain saw (12). The shut-off device (104) includes a switch (54) biased off and shiftable on. A pivotable or shiftable trigger (72) is shifted toward but remains out of contact with the switch (54). A link (92) is caused to shift responsive to the brake (34) when the brake becomes operative, but the link is otherwise disposed intermediate the switch (54) and the trigger (72) to permit the trigger (72) movement to actuate the switch (54). However, on brake actuation the link is removed from a path of motion between the switch (54) and trigger (72) thereby to restore the switch (54) to "off" position. Once the link (92) is removed from the path of motion it cannot be reinserted therein until after the trigger (72) is released.

Abstract: A string trimmer having a handle, frame, motor and head. The head includes a housing formed by a cover and a base which contains a coiled supply of trimming line. The lower housing member has a central opening and a radial passage for the trimming line so that the trimming line can be fed from the storage coil through the central opening and the radial passage to project radially-outwardly from the head. Several types of convenient clamping arrangements are disclosed which clamp the trimming line during operation of the trimmer and release the trimming line for feeding of replacement portions of the trimming line.

Abstract: A manually portable chain saw (10) having a gripping handle (18), a cutting chain (26), a sensing arm (30), and a motive force mechanism (14), features a releasable bistate mechanism (39a) for stopping cutting chain movement in response to forward movement of the sensing arm (30). The releasable bistate assembly (39a) captures an end of a brake band (40) for longitudinal movement in the direction of the brake band (40) and transverse movement in the direction of the long axis of the sensing arm (30). Independent adjustment of the forces on the sensing arm (30) and on the latch mechanism (49), and positive braking action are achieved. Separate spring biases (50, 52) are employed against the sensing arm (30) and the latch mechanism (49) respectively.

Abstract: An armature winding distribution for an electric motor divides each armature coil into first and second coil sub-sections inter-distributed with one another so that the first and second coil sub-sections of an armature coil undergoing commutation at one of the brushes are coupled, respectively, to the coil sub-section of an armature coil about to undergo commutation by the other brush and the coil sub-section of another armature coil having just completed commutation by the other brush. Excess energy in the armature coil undergoing commutation by the first-mentioned brush is transferred to a coil sub-section of the coil just about to undergo commutation and/or a coil sub-section of the coil having just completed commutation by the other of the brushes. The armature winding distribution improves commutation and substantially reduces brush sparking and the generation of electromagnetic interference (EMI) across a wide range of frequencies.

Abstract: There is disclosed a hand-held portable tool which is driven by an electric motor from a source of electricity. The tool has a housing for the motor which has a commutator which extends into a hollow handle. The hollow handle has mounted therein a printed-circuit board having electrically conductive pathways. An electric switch is mounted on the board and incorporates a bridging element which engages contact terminals on the printed-circuit board when the switch is manually actuated thereby closing the electric circuit of the tool motor. In this way, separate electrical connections to the switch assembly per se are avoided and substantial time in assembly of the tool is saved.

Abstract: A plunge type router is disclosed which includes an improved depth lock system operative to exert a clamping force directly on the motor housing and which distributes the clamping force over a substantial surface area thereof whereby the motor housing may be securely retained in position without damaging or distorting the housing. An adjustable depth stop system is also provided which provides a positive, easily, accurately adjustable stop member engageable by a portion of the motor housing and an associated rack and pinion adjustment assembly operative to accurately locate the stop member so as to provide positive control of the depth of cut.

Abstract: A plunge type router is disclosed which includes a base housing having a work engaging surface and an upper portion within which a driving motor is supportingly mounted for reciprocable movement with respect thereto. A pair of extension coil springs are provided extending between a first pair of projections provided on the upper portion of the base housing and a second pair of projections secured to the motor housing which operate to continuously bias the driving motor into a retracted position. The extension springs are arranged in the form of loops positioned on opposite sides of the router and are concealed and protected by a pair of handles secured to the motor housing which handles are movable therewith.

Abstract: A microcomputer controlled power tool including a semiconductor control device connected to the motor, one or more sensors, and a microcomputer interfaced to a keyboard and digital display for monitoring and controlling various operating conditions and parameters of the power tool.

Abstract: A chain saw is provided with a compact lever system which has the dual functions of tensioning the cutting chain and of protecting the operator from a broken chain.

Abstract: A tool guide for providing controlled support for a portable power tool such as an electric drill. When the lower portion of the device is clamped between the vise jaws of a portable workbench and vise, an electric drill slidably mounted on the device may be used to drill either perpendicular or angular holes in a workpiece positioned on top of the vise jaws. The device may also be used independently to add accuracy to free hand drilling for both perpendicular and angular holes.

Abstract: This disclosure relates to a sound absorbing arrangement for a power lawnmower in which sound absorbing material is provided within the body of the lawnmower to reduce noise by attenuating resonance caused by the lawnmower motor. In addition to reducing noise, the sound absorbing material imparts structural rigidity to the lawnmower body or housing, and also may be used to define air passages within the lawnmower body for use in cooling the motor.