Abstract: A keyless adjusting mechanism for a chain saw is disclosed herein, which comprises a protection cover, an adjusting bolt, an adjusting stud, and an adjusting ring with a driver gear, wherein the adjusting bolt is coupled with a driven gear for engaging with the driver gear of the adjusting ring, the adjusting stud is coupled with a chain board and has a threaded hole for engaging with the corresponding adjusting bolt. Accordingly, when the adjusting ring is rotated, the driver gear can bring the driven gear to let the adjusting stud move axially along the adjusting bolt such that the chain could be adjusted to tighten or loosen. In addition, a knob with a handle is coupled to the adjusting ring. The handle can be withdrawn in the knob or extended out of the knob for convenient twist.

Abstract: A tension-adjusting device for a chain in a chain saw comprises an adjusting assembly, a fixing base, a brake disk, a position piece and a fixing piece, wherein the adjusting assembly, the brake disk, the position piece and the fixing piece are locked together on the fixing base by a bolt. The adjusting assembly further comprises a knob, a nut, a fixing member, and an adjusting ring. An operator merely needs to rotate the knob of the adjusting assembly to drive the adjusting ring and the brake disk, such that the position piece can be moved forward and backward, thereby to attain the tension adjustment of chain.

Abstract: A saw chain tensioning mechanism for adjusting the tension in a saw chain extending around a chain guide plate includes a threaded rod member disposed adjacent to a rear end of the chain guide plate and along the longitudinal direction of the chain guide plate, a movable member engaged with the chain guide plate and adapted to be moved along the threaded rod member by a rotation of the threaded rod member, and a driving gear integral with the threaded rod member. The tensioning mechanism includes a driving gear for rotatively driving the driving gear and an operating member for manually rotating the driving gear. Manipulating the operating member changes the longitudinal position of the chain guide plate and correspondingly causes a change in a tension of the saw chain.

Abstract: A chain saw automatic tensioner preferably includes a base plate, a chain bar, a tensioning cylinder, a sliding block and a pusher block. The base plate includes a sliding slot that is sized to slidably receive the sliding block. The chain bar includes a substantially half oval shape that is sized to retain a cutting chain. An end of the chain bar is retained between a top of the sliding block and a bottom of the pusher block. The tensioning cylinder is mounted to the base plate opposite the sliding slot. Hydraulic oil in the tensioning cylinder forces a cylinder rod and the pusher block secured to the chain bar away from a chain sprocket and thus tensioning the cutting chain.

Abstract: A chain saw bar tensioning apparatus is disclosed comprising a sliding member having a recess formed therein. The sliding member is adjacent to a first tensioning member that biases the sliding member in a direction such that when the apparatus is incorporated into a chain saw bar and mounted to a chain saw having a mounting stud, the sliding member is biased towards the mounting stud. The apparatus further comprises a latch adjacent to a second tensioning member. The recess of the sliding member is configured to receive the latch and the second tensioning member biases the latch towards the sliding member such that, when the sliding member is forced in a direction away from the mounting stud, the latch will eventually enter the recess and prevent the sliding member from moving towards the mounting stud.

Abstract: A chain saw includes an engine, a chassis, and a clutch cover. A guide bar is adjustable relative to the chassis and the clutch cover, but stationary while in a secured position. An adjustment arrangement moves the guide bar to tension a chain, and includes a member operatively connected to the bar, intermeshed drive components to move the bar, and a manually engaged member that is operated without use of any tool. A guide bar securing arrangement has a knob rotatable between a tightened and loosened positions. In the loosened position, the guide bar may be adjusted. A knob handle of the securing arrangement is pivotable between a stowed position and an operation position. A lock arrangement, associated with the knob and knob handle, includes portions that cooperate to prevent the knob from rotating when the knob handle is in the stowed position.

Abstract: A retaining assembly is provided for a tensioning arrangement for adjusting the tension of the cutting chain in the chainsaw. The retaining assembly includes a knob body, a lock, and a lever. The lock and lever rotate about a common axis, which is perpendicular to an axis of rotation of the retaining assembly. The lock includes a tooth adapted to engage with teeth on a clutch cover of a chainsaw to lock the retaining assembly in place.

Abstract: A chain saw which includes chain tensioning and braking systems. Tensioning and braking are caused by the presence and control of longitudinal and lateral slits in an elongated support which provides a continuous chain channel guide in its outer circumference.

Abstract: The invention concerns a motor powered saw with a saw chain (2) and a guide bar (1), the rear portion of which is covered by a side cover (3) and during operation clamped with a certain clamping force between the side cover and a counter support on that side of the guide bar which is turned towards the motor, tensioning elements being provided for tensioning the saw chain by displacing the guide bar forwards, when the guide bar has been loosened by easing the clamping force, and elements for securing the guide bar in a new position.

Abstract: A tensioning mechanism for adjusting tension of a cutting chain in a chain saw. A rotatable knob operates with an engine chassis, clutch cover, and guide bar, whereby the knob may be rotated between a tightened position and loosened position, by which the guide bar is loosened and may be adjusted. The knob is provided with a knob handle, pivotally connected to the knob and pivotable between locked and unlocked positions. When the knob handle is in the locked position, at least one, but not all, of a plurality of handle engagement points engage with corresponding fixed engagement points that are fixed relative to the clutch cover. When the knob handle is in the unlocked position, the handle engagement points are disengaged from the fixed engagement points. Further, the engagement points are visible when the knob handle is in both locked and unlocked positions.

Abstract: The chain tension of a motorized chainsaw (10) with a housing (12), a sprocket (22) mounted thereon, and a blade (14) that is aligned with this sprocket, which blade protrudes beyond the housing (12) and guides a saw chain (16) engaged with the sprocket (22) in a revolving manner, where the blade (14) is mounted such that it can be adjusted by means of longitudinal displacement in relation to the housing (12) and/or the sprocket (22) by means of a chain tensioning device (28) and where the chain tensioning device (28) has a stop (32) that can be fixed to the blade (14) and a cam (30) that can be rotated by means of a rotational member (36, 38) can be adjusted in a more comfortable and reliable fashion by virtue of the fact that the cam (30) can be locked in a form-fitting and rotationally secure manner in relation to the housing (12) by way of the rotational member (36, 38).

Abstract: A chain saw bar tensioning apparatus is disclosed comprising a sliding member having a recess formed therein. The sliding member is adjacent to a first tensioning member that biases the sliding member in a direction such that when the apparatus is incorporated into a chain saw bar and mounted to a chain saw having a mounting stud, the sliding member is biased towards the mounting stud. The apparatus further comprises a latch adjacent to a second tensioning member. The recess of the sliding member is configured to receive the latch and the second tensioning member biases the latch towards the sliding member such that, when the sliding member is forced in a direction away from the mounting stud, the latch will eventually enter the recess and prevent the sliding member from moving towards the mounting stud.

Abstract: A cam lever arrangement is provided which permits the loosening and tightening of the chain on the chain saw blade tool with a simple lever motion. The lever arrangement is connected to the motor housing cover door. Opening the door automatically loosens the chain. Closing the door automatically tightens the chain. Precision adjustments to tension are easily made in the cam lever arrangement by hand manipulation of a turnbuckle which is free from pressure when the lever is in the release position.

Abstract: The invention relates to a portable handheld work apparatus including an overhead branch cutter. The work apparatus has a drive motor (4) mounted at one end (2) of a carrier tube (3). A work tool (6) is held at the other end (5) of the carrying tube (3). The work tool (6) is driven via a shaft (7) mounted in the carrying tube (3). A variable work position of the portable handheld work apparatus is made possible by subdividing the carrying tube (3) into two sections (8, 9). The sections (8, 9) can be pivoted relative to each other (pivot angle 11) with respect to their longitudinal axes (52, 51) and are rotatable relative to each other (rotation angle 12) and are connected by a ball-and-socket joint (10). A device is provided for fixing the ball-and-socket joint (10) and permits the ball-and-socket joint (10) to be fixed in the desired position.

Abstract: In a chain saw having a sprocket (11), which is supported in rotary fashion in a housing (10) and is for a saw chain (12) guided on a guide (13), and having a chain tension device (14) for longitudinally moving the blade (13), which device has a cam (15) that moves the guide (13) and a rotating member (17) for rotating the cam (15), in order to preset a chain tension that is optimal for operation and is independent of the user, the rotary connection between the rotating member (17) and cam (15) is embodied as a detent overload clutch (18), whose detent overload force is set in accordance with the required chain tension (FIG. 2).

Abstract: An arrangement that provides a semi-automatic tension adjustment of an endless cutting chain on a guide bar of a chain saw as the links of the chain wear with use. A specially designed cam biases a tensioner pin to continuously force the guide bar away from the drive sprocket on the engine chassis to tension the chain. A knob on a clutch cover assembly attached to the engine chassis can be tightened to force two high friction surfaces together to lock the guide bar in a tensioned position, or loosed to release the guide bar to seek a proper tensioned position. An override lever on the face of the clutch cover assembly moves in a channel with peripheral nomenclature that indicates when the cutting chain should be replaced. The entire arrangement is self-contained and does not require any tools to function.

Abstract: A hydraulic stretching device for a saw chain active in sawing apparatus having a saw bar and including a holder (1), a driving wheel (3) for the saw chain arranged essentially stationary in relation to the holder and a guiding part (7) permanently arranged at a saw bar to interact with the holder (1). The guiding part (7) is permanently attached to resist turning and axially displaceable in relation to the holder (1) in the longitudinal direction (8) of the saw bar to allow stretching of a saw chain running round the saw bar (6) and the driving wheel (3). The stretching device for a saw chain is arranged to be active between the holder (1) and the guiding device (7) and including a hydraulically influenced piston (10). The piston (10) is arranged in a displaceable manner at the holder in parallel with the longitudinal direction (8) of the saw bar and has an engaging surface (11) intended to engage an opposing surface (12) on the guiding part (7).

Abstract: An adjusting device has a driving disk with two diametrically oppositely formed arcuate tracks formed thereon and a driven plate securely connected to the chain saw and having multiple bosses evenly and horizontally distributed on the driven plate. The two arcuate tracks are alternately received between two adjacent bosses such that when the driving disk rotates, the driven plate is moved linearly, which results in the adjustment of the tension of the chain saw.

Abstract: An arrangement that provides a semi-automatic tension adjustment of an endless cutting chain on a guide bar of a chain saw as the links of the chain wear with use. A specially designed cam biases a tensioner pin to continuously force the guide bar away from the drive sprocket on the engine chassis to tension the chain. A knob on a clutch cover assembly attached to the engine chassis can be tightened to force two high friction surfaces together to lock the guide bar in a tensioned position, or loosed to release the guide bar to seek a proper tensioned position. An override lever on the face of the clutch cover assembly moves in a channel with peripheral nomenclature that indicates when the cutting chain should be replaced. The entire arrangement is self-contained and does not require any tools to function.

Abstract: A chain saw (1) includes a guide bar (5) supporting a chain (7) and attached to a main body (3). Disposed within the body is an anchor bolt (9) for securing the guide bar to the main body. Disposed within a sprocket cover (8) is a hexagonal nut (11) screwed onto the anchor bolt. Furthermore, provided coaxially with the hexagonal nut is a cylindrical element (15) having a hexagonal cavity (13) that engages the hexagonal nut and is axially movable and rotatable about the same axis as the hexagonal nut. Also provided is a lever (17) disposed at the outer end of the cylindrical element. Provided within the sprocket cover are an adjustment pin (19) engaging the guide bar, a screw stock (20) onto which the adjustment pin is threaded and which extends in the axial direction of the guide bar, a first helical gear (21) disposed at one end of the screw stock, and a second helical gear (23) meshing with the first helical gear. Further provided is a rotating element (25) coaxial with the second helical gear.

Abstract: A power chain saw with a drive motor arranged in a housing drives a saw chain circulating on a saw guide, wherein the saw guide is held clamped by one end transversely to its surface plane between the housing and a tightening element, and for tightening the saw chain can be displaced in the longitudinal direction L when the tightening element is detached. The power chain saw also includes detent plates arranged between the saw guide and the housing and/or between the saw guide and the tightening element, which permit the displacement of the saw guide in the tightening direction, but block it in the loosening direction of the chain. The tightening element can be embodied as chain wheel protector.

Abstract: The chain tension of a motorized chainsaw (10) with a housing (12), a sprocket (22) mounted thereon, and a blade (14) that is aligned with this sprocket, which blade protrudes beyond the housing (12) and guides a saw chain (16) engaged with the sprocket (22) in a revolving manner, where the blade (14) is mounted such that it can be adjusted by means of longitudinal displacement in relation to the housing (12) and/or the sprocket (22) by means of a chain tensioning device (28) and where the chain tensioning device (28) has a stop (32) that can be fixed to the blade (14) and a cam (30) that can be rotated by means of a rotational member (36, 38) can be adjusted in a more comfortable and reliable fashion by virtue of the fact that the cam (30) can be locked in a form-fitting and rotationally secure manner in relation to the housing (12) by way of the rotational member (36, 38).

Abstract: A power cutting device for cutting material in tight places. The power cutting device includes a power cutting device comprising a housing. The housing includes a first end and a second end. A first shaft is securely coupled in and extending away from the housing. A handle member is integrally coupled to a second end of the housing. A motor is positioned generally in the housing. A power supply for powering the motor is operationally coupled to the motor. A first actuating element for starting the motor is positioned in the handle member and operationally coupled to the motor. A first gear is mechanically coupled to the motor. A blade supporting member for supporting a cutting a member is positioned generally in the housing and removably coupled to the first shaft. A cutting member for cutting a variety of materials is movably coupled to the blade supporting member and the first gear.

Abstract: An easily engageable and releasable chainsaw bar guard for protecting an individual carrying a chainsaw and for preventing damage to the cutter chain and saw dogs of a chainsaw. The bar guard comprises an elongated stiff hollow sleeve whose interior space is just slightly larger than the bar and chain to be protected. The sleeve has an opening at the proximal end for sliding the sleeve onto the guide bar, and is closed at the other end to protect the end of the bar and cutter chain. A snap-clip mechanism is fixed to the sleeve for releasably latching the proximal end of the guard to the chainsaw. The snap-clip mechanism biases a retaining claw into contact with the chainsaw bar between the nuts on the saw bar attachment/adjustment bolts. The sleeve and the snap-clip mechanism can be selectively configured to accommodate chainsaw bars of different shapes and dimensions and the spacing of whose guide bar adjustment nuts varies.

Abstract: A chain saw includes a chain arranged on a saw flange (5). The chain saw is usually arranged in a multi-purpose head of forestry machinery by a mounting flange (1) immobile in regard to the multi-purpose head, whereby the chain is rotated by a chain wheel (4) controlled by a power unit. In order to tighten the chain, the saw flange, or a relevant part of the chain saw comprising the same, is arranged to move parallel with the longitudinal axis (A) of the saw flange in regard to the chain wheel. This is achieved by a tightening device and at least one supporting guide therein which are attached to the mounting flange of the chain saw or a structure arranged therein. By arranging the supporting guide in the tightening device to extend onto both sides of the center of the chain wheel parallel with the longitudinal axis of the saw flange, the saw flange is made to move in a completely supported manner parallel with its longitudinal axis in regard to the chain wheel.

Abstract: A chain saw (1) includes a guide bar (5) supporting a chain (7) and attached to a main body (3). Disposed within the body is an anchor bolt (9) for securing the guide bar to the main body. Disposed within a sprocket cover (8) is a hexagonal nut (11) screwed onto the anchor bolt. Furthermore, provided coaxially with the hexagonal nut is a cylindrical element (15) having a hexagonal cavity (13) that engages the hexagonal nut and is axially movable and rotatable about the same axis as the hexagonal nut. Also provided is a lever (17) disposed at the outer end of the cylindrical element. Provided within the sprocket cover are an adjustment pin (19) engaging the guide bar, a screw stock (20) onto which the adjustment pin is threaded and which extends in the axial direction of the guide bar, a first helical gear (21) disposed at one end of the screw stock, and a second helical gear (23) meshing with the first helical gear. Further provided is a rotating element (25) coaxial with the second helical gear.

Abstract: A valve device including a cylindrically-shaped space and a displaceable piston dimensioned to fit and move between forward and rearward stop positions within the space, having a first opening connection or inlet to the hydraulic system and a second opening connection or outlet to the tightening piston in the space and an openable check valve positioned in the outlet such that the check valve allows fluid to flow only in one direction from the cylindrically-shaped space to a hydraulic tightening piston in a sawing gear for adjusting the tightness of a saw chain.

Abstract: A tensioning device for a chain or a belt drive for a motor of a hand machine tool, especially for a chain saw or a grinding or abrasive cutting-off machine, with a longitudinally movable bracket, such as a bracing or an arm, which can be fixed together with a cover with at least one bolt with a screwable nut to a casing or to another part of the hand machine tool, whereby the tensioning device has an adjusting screw extending in the longitudinal direction of the bracket on which a rider screw is movable to-and-fro by rotating the adjusting screw, the rider screw having a trunnion extending through an opening of the bracket so that, for tensioning the chain or the belt drive, the bracket follows a movement of the rider screw.

Abstract: A mounting mechanism for an adjustable component that is to be held against an abutment surface of a housing, especially for the guide bar of a power chain saw, is provided. The mechanism includes at least two bolts that are provided on the housing, are spaced from one another, and project beyond the abutment surface of the housing and into an elongated opening of the component. At least one device is provided that extends into a gap between one of the bolts and at least one of the longitudinal edges of the elongated opening for engaging such at least one longitudinal edge.

Abstract: A chain saw guide bar has a pair of elongated chain guide plates, which are superimposed with each other and receive a saw chain. Positioning slots extend in the longitudinal direction of the guide plates and receive a pair of fixing stud bolts that project from the main body of the chain saw. A chain-tightening device, which is incorporated into the guide bar, includes a pulley carried by the guide plates in a fixed position distally of the guide slots. One end of a flexible wire is connected to the pulley. The other end of the flexible wire is connected to a circular ring that is slidably received between the guide plates with an opening thereof at least partly registering with the positioning slots. The ring is received on one of the fixing stud bolts. An intermediate portion of the wire is turned partway around a returning member that is stationarily located on a portion of the guide bar proximally of the fixing stud bolt that receives the ring.

Abstract: A chain saw has a spacer plate that provides an initial clearance space between an outer surface of an elongate flat blade that carries the cutting element of the saw and an inner surface of a recessed wall formed in a motor cover that forms a part of the chain saw housing when a pair of locking nuts are loosely seated against an outer surface of the recessed wall. When the locking nuts are firmly seated, the initial clearance space is reduced to no clearance space and the elongate flat blade is firmly held against vibration, but the light contact between the elongate flat blade and the recessed wall enables the elongate flat blade to be displaced in a first direction to loosen the cutting element and in a second direction, opposite to the first direction, to tighten the cutting element. This eliminates any need to loosen the locking nuts to accomplish cutting element adjustment. The spacer plate extends through an elongate slot formed in the elongate flat blade.

Abstract: A chain tension device for tensioning a cutting chain of a chain saw utilizing a guide bar having an outer periphery and a drive sprocket. The chain saw body supports the guide bar, the sprocket and a drive source. A cutting chain is wound around the sprocket and the outer periphery of the guide bar and a leaf spring is supported by the chain saw body and interposed between the guide bar and the sprocket. The leaf spring abuts and biases the guide bar away from the sprocket so as to apply automatically an appropriate amount of tension to the cutting chain.

Abstract: A chain saw guide bar including a chain tightening mechanism. A shaft or rack slidable within the bar body includes a head portion slidable rearwardly against a bar mounting stud. The head portion resides between opposed edges formed in the bar body and the head portion includes fingers that straddle the mounting stud. Rearward sliding of the shaft or rack against the stud produces a lateral force urging spreading of the fingers to produce wedging of the fingers between the opposed edges and the stud. Such wedging of the fingers produces resistance to return sliding of the shaft and retains the tightened condition of the chain.

Abstract: A chain saw guide bar has self-contained mechanism to force movement of the guide bar away from a drive sprocket to tension the saw chain. The mechanism includes a bearing surface that engages a mounting stud on the chain saw housing and a rotatable portion which upon rotation causes axial displacement of the bearing surface in contact with the stud.

Abstract: A chain saw includes a chain formed into a closed loop about a drive sprocket and a support bar. A first piston is operable to move the support bar radially away from the drive sprocket, and a second piston is operable to limit such movement.

Abstract: A portable, hand-guided working tool has a drive motor and a motor housing in which the drive motor is housed. The motor housing has a front side and a rear side when viewed in the direction of the longitudinal center axis of the working tool. A tool member is connected to the front side of the motor housing and extends forwardly in the direction of the longitudinal center axis. The tool member is driven by the drive motor. The rear grip is connected by vibration damping elements to the rear side of the motor housing and extends rearwardly in the direction of the longitudinal center axis. An abutment device includes a first abutment member connected to the motor housing and positioned between the rear end and the rear grip and includes a second abutment member connected to the rear grip and cooperating with the first abutment member for limiting a relative movement between the motor housing and the rear grip.

Abstract: A chain saw includes a motor unit and a guide bar clamped thereto by a clamping plate. The guide bar, which supports a saw chain, has a longitudinal slot formed therein. Clamping bolts carried by the motor unit pass through the slot and through the clamping plate for securing the clamping plate to the motor unit. One (or both) of the side edges of the slot includes corrugations. The clamping plate includes a hole aligned with the corrugations to enable a toothed key to be arranged in meshing engagement with the corrugations whereby a rack-and-pinion relationship is formed. By manually rotating the key, the guide bar is longitudinally displaced for varying the tension on the saw chain.

Abstract: A chain tensioner for a chain saw has a cam member in positive engagement with a flange of a plate attached to the guide bar. Rotation of the cam member forces the guide bar away from a drive sprocket of the chain saw to tension the chain. The cam member is clamped in position to maintain the guide bar in the adjusted position. Flats on the cam member in abutment with the flange resist rotation of the cam member when in the adjusted and clamped position. A slot is provided in the cam member to facilitate rotating the cam to force the guide bar away from the drive sprocket.

Abstract: A chain saw includes a drive unit having a drive shaft, and a chain guide bar mounted to the drive unit by two bolts. The guide bar is attached to the drive unit by an insert structure which fits into a longitudinal slot of the guide bar. The insert structure can be oriented in at least two different orientations within the slot for establishing different positional relationships, respectively, between the drive shaft and a longitudinal center line of the guide bar. For example, the center line could be offset either above or below the drive shaft, or the center line could intersect the drive shaft.

Abstract: There is disclosed a tree harvesting apparatus which provides a helical spline for permitting movement of a harvesting head about a central vertical axis thereof. This provides enhanced manoeuverability of the head to prevent damage to saplings or other immature timber. A chain saw chain detensioning system is also disclosed. The system permits a quick removal of a saw chain from the chain saw without the use of tools therefore is more easily changed in an expedited manner.

Abstract: A saw assembly comprising a bar (9) mounted in a holder (24); a displaceable unit (22) including the bar (9) and mounted on the bar holder (24) to displace the bar (9) in relation to the holder (24); and a first hydraulic piston cylinder member (16) which displaces the unit (22) in relation to the bar holder (24) so that the bar (9) automatically stretches the saw chain (11). According to the invention the displaceable unit (22) comprises a block element (25) which is joined to an inner bar attachment (20) supporting the bar (9), a small gap thus being formed between opposing surfaces, the cylinder member (16) being arranged in the block element (25) to abut against the bar holder. A second hydraulic piston cylinder member (17) is arranged in the block element (25), parallel with the axis of rotation (36) of the bar holder, the piston cylinder member (17) being arranged to abut against the bar holder (24) in order to secure the unit (22) to the bar holder (24) and eliminate the clearance produced by the gap.

Abstract: The chain saw tensioner of the present invention provides a sheath anchored at one end to the housing of the chain saw which sheath receives a tensioning shaft slidably therein. The tensioning shaft is interconnected with the housing by a tension screw and is slidably adjustable with respect to the sheath by actuating the tensioning screw. The tensioning shaft and the sheath have matching and aligned slots that cooperate to receive a sliding bolt therethrough. The sliding bolt is interconnected with the blade of the saw and, by actuating the tensioning screw, it may be moved forward with respect to the housing of the saw to move the saw blade forward to tension the chain. Included within the tensioning shaft is a spring interconnected with a bolt rest for receiving and supporting the sliding bolt. The spring provides a bias which acts on the bolt to bias the bolt, and accordingly the saw blade, forward with respect to the housing to tension the chain.

Abstract: The invention is directed to a tensioning arrangement for saw chains of motor-driven chain saws which include a device for longitudinally displacing the guide bar. The clamped guide bar is released so that the adjusting arrangement can be actuated for the longitudinal displacement of the guide bar. By rotating a disc having a spiral slot, a slide piece, which is coupled to the guide bar, is displaced in the longitudinal direction. Assembly is simplified and handling facilitated when the tension in the saw chain is adjusted. This is achieved by making the slide piece on the spiral disc so that it is not released therefrom but instead is held so as to be rotationally and longitudinally displaceable. The slide piece is fixedly connected to the guide bar by using appropriate attachment devices.

Abstract: In a chain saw including a housing (10) and a guide bar (11) provided with a saw chain (16), the guide bar is releasably attached at one of its ends to the housing and axially slidable by means of an adjusting means to adjust the tension of the saw chain. The adjusting means comprises a screw (17) extending generally parallel to the guide bar and having one end attached to the housing in a non-rotatable manner, and a nut (18) engaging the screw and being operatively connected to the guide bar in order to provide an axial adjustment of the guide bar by rotation of the nut. The nut is rotated by means of a gear (19, 20) having a drive shaft (21) extending through a bore (22) in the guide bar.

Abstract: The invention is directed to a tensioning arrangement for a saw chain of a motor-driven chain saw. The saw chain runs on a guide bar mounted on the motor housing of the chain saw. The tensioning arrangement includes a rotatable disc having a spirally-shaped guide slot in which a lug of a slide piece engages. The longitudinal displacement of the guide bar is provided by rotating the disc. The guide slot in the disc extends over a rotational angle of at least 270.degree.. A still lesser slope of the guide slot is provided with a rotational angle in the range of 360.degree. to 450.degree.. The tensioning arrangement is especially suitable for adjusting the guide bar in motor-driven chain saws thereby adjusting the tension in the saw chain.

Abstract: A power-operated sword saw comprises a plate-shaped sword having a lower region with a guiding groove, two saw blades reciprocatingly movable in opposite directions parallel to one another and each having a front saw blade tip and an opposite clamping end. The saw blades have a toothed side provided with a plurality of teeth and an opposite saw blade back guided in the guiding groove of the sword. A drive is coupled with the clamping ends of the saw blades through a clamping unit. The saw blades are jointly coupled with the clamping unit and released from the clamping unit by a blocking element which blocks the clamping ends in a coupling position and release the clamping ends in a contact-free manner.

Abstract: A mounting base for chain saw guidebars, comprising a plate (11) with a slot (14) in which a guide piece (36) can slide in the lengthwise direction of the guidebar, said guide piece being acted on by one or more pistons (17) energized by a self-contained pressure source (19) preferably comprising a gas spring, and a valve device (18) which can be set in different positions, during sawing urging the guidebar outwards with a predetermined force and preventing displacement inwards, and during changing of saw chain or guidebar permitting displacement inwards of the guidebar while preventing the pistons (17) from urging the guidebar outwards.

Abstract: The invention is directed to a motor-driven chain saw having a drive motor arranged in a housing. The drive motor drives a saw chain on a guide bar via a sprocket wheel. The guide bar extends forwardly in the longitudinal direction of the chain saw and has an elongated slot in its rearward end facing toward the housing. Stud bolts fixed on the housing extend through the elongated slot in a direction transverse to the longitudinal direction of the chain saw. The rearward end of the guide bar is clamped between the housing and a sprocket-wheel cover through which the stud bolts extend. A holding device separate from the sprocket-wheel cover is provided at the rearward end of the guide bar for holding the rearward end of the guide bar in its position on the housing when the sprocket-wheel cover is removed. This holding device reliably holds the guide bar for mounting the saw chain.

Abstract: The invention is directed to a cutting arrangement for a motor-driven chain saw and is configured as a preassembled component which includes a guide bar having a saw chain and sprocket drive wheel. A tensioning device is integrated into the guide bar for holding the parts of the component together. The tensioning device holds the sprocket drive wheel at a spacing from the end face of the guide bar. The tensioning device is adjustable when placing the component on the housing of the chain saw in such a manner that the sprocket drive wheel is released while the saw chain remains under tension. The component can be disassembled into its individual parts by adjusting the tensioning device.

Abstract: A belt tension system for a power tool such as a demolition saw. The system includes a driven gear and a drive gear. The drive gear is orientated perpendicular to the driven gear for more convenience access to adjust the driven gear and, hence, adjust the drive belt. The driven gear can include a second member movably connected to a first member. The second member has a threaded portion and a shaft portion. The first member has helical grooves to interact with the drive gear and a center hole with the second member shaft portion slidingly located therein. The first member can axially rotate the second member when it is axially rotated.