Background of the Art When tools are used for work performed in primitive environments, such as woods, problems arise when necessary maintenance work on the tools cannot be postponed until the return to civilisation but has to be performed at the place of work. Also other types of tasks that require for instance a fixedly anchored worktable may be difficult to perform in a primitive environment.

One problem connected with this mode of operation thus is that the operator may have to place the tool on the ground and to work while kneeling beside it while performing the maintenance work, which position, apart from being uncomfortable, may also be detrimental to the health.

Another problem is that it is also difficult to perform high-quality maintenance work while assuming this working position.

In order to eliminate this problem it is suggested in US-4 657 234 to use a device of the kind defined in the preamble of claim 1 to perform maintenance work on power saws, such as refilling of fuel and oil and repairs on the power saw guide bar. The most serious problem encountered with this type of device is that the guide bar of the power saw cannot be kept completely immobile in the relevant maintenance position, with consequential poorer. quality of the resulting maintenance work. In addition, it is difficult to find the optimum work position within an acceptable time limit. This is so partly because the second part of the device is arranged to be fastened to the handle of the power saw, which handle is movable relative to the power saw motor and guide bar. Consequently, a movable and not entirely fixed connection between the device and the power saw is obtained.

Summary of the Invention The object of the present invention is to remedy the above problems by enabling the tool to be held in an entirely fixed position while assuming the optimum work position.

This object is achieved in accordance with the teachings of the invention by means of a device of the kind defined in the introduction and which is characterised in that the second part is provided with a clamping means (22) for securing the tool (1) to the second part, and in that the second part (14) and/or the first part (2) is/are provided with indexing means (35)

to position a tool (1), which is clamped to the second part, in at least two predetermined, fixed angular positions relative to the first part.

Owing to the provision on the first and/or the second part of the device of an indexing means it becomes possible to rapidly position the tool in an optimum work position.

Because the entire tool is fixedly coupled to the second part during the maintenance work a fixed interconnection between the two components is obtained, with the result that the tool assumes the same position relative to the second part one for the duration of the entire maintenance work.

Preferably, the first part is formed by a support member, which is designed to abut against the fixed support, and by a fastening means to fasten the support member to the support.

The second part, on the other hand, preferably is formed by a worktable, which is rotatably mounted on the first part, and a clamping means to clamp the tool to the worktable.

Preferably, the indexing means consists of an indexing disc provided on the first or on the second part and having recesses formed therein, said recesses co- operating with locking means provided on the first and the second part, respectively, to fix the tool in the above referred-to angular positions.

The tool could be a power brush saw, a lawn trimmer, a leave suction device, power hedge shears and the like, the corresponding clamping means being adapted accordingly. The tool could also be a saw, more particularly a power saw having a guide bar with a saw chain, which guide bar is supported on the worktable

while maintenance work is being performed thereon.

Because the power saw guide bar is supported on the worktable during the maintenance work, which table thus functions as a holder-up face, the fixation of the guide bar becomes additionally secure and stable during the maintenance work with consequential improvement of the quality of the maintenance work.

The guide bar of the power saw preferably is provided with at least one through-hole to enable the saw chain to be tensioned to compensate for any slack.

Preferably, the worktable is provided with at least one indexing pin, which is positioned in such a manner on the worktable that the guide bar will assume an optimum position on the worktable, when the hole of the guide bar is placed over the pin.

Brief Description of the Drawings The invention will be described in the following in more detail with reference to the accompanying drawings, which for exemplifying purposes illustrate a presently preferred embodiment of the device in accordance with the present invention.

Fig 1 is a perspective view of the device together with a device-supported power saw in a horizontal position.

Fig 2 is a view of the device of Fig 1 as seen straight from the side, the device assuming a second vertical position and the power saw having been omitted from the device for more clarity.

Detailed Description of Preferred Embodiments The device in accordance with the preferred embodiment is intended to temporarily support and hold a

power saw (chain saw) 1, to be used when maintenance work needs to be performed on the saw in a primitive environment, such as in woods. By simple adjustments, the device could of course be used to hold also other types of tools, such as power brush saws, lawn trimmers, leave suction devices, power hedge saws, and the like.

The device comprises a first part 2 designed to fasten the device about a tree trunk 3 having a shape allowing it to serve as a fixed support. The first part 2 is formed by a support member 4 configured to abut against the tree trunk, and by a fastening means designed to fasten the support member to the tree trunk.

The support member extends in the longitudinal as well as the transverse directions of the tree trunk 3, and in this manner a comparatively large support area is provided on the tree trunk, with consequential reduction of the pressure on and the risk of damages to the tree trunk bark. The member further is formed by two yoke- shaped support sections 6,7, which are welded to an L- shaped beam 8, spaced a predetermined distance apart. In turn, each support section 6,7 is formed by two support legs 6a, 6b and 7a, respectively, which abut against the tree trunk and which are interconnected by means of a stay element 9. The legs are configured to diverge both relative to one another and to the corresponding support legs on the other support section. For improved abutment against the tree trunk, the free outer ends of the legs are bent outwards. In order to avoid damages to the tree trunk, an outer plastic cover could be provided on the legs.

The fastening means 5 consists of a chain 10 and a rotary disc 11. One end of the chain is attached to the rotary disc 11 by means of a bolted joint 12, see Fig 2.

In order to avoid damages to the tree trunk, also the chain may have an external cover of plastics. The bolted joint is positioned off-centre relative to the fulcrum of the rotary disc, resulting in a so called over-centre locking of the chain. In turn, the rotary disc is mounted on a bracket for rotational movement thereon, and one end of said bracket is welded to the L-shaped beam 8 and the opposite end to the stay 9 of one of the support section 6. An operating arm 13 is provided to actuate the disc.

The opposite end of the chain could be attached to a securing means, not shown, which in turn is attached to the stay, not shown, of the second support section 7. The securing means is designed as a plate having a recess formed therein for introduction and locking therein of the free end of the chain in a position ensuring fastening of the support member to the tree trunk.

The device likewise comprises a second part 14 designed to hold and support the power saw 1, more precisely the saw guide bar 16. As appears from Fig 1, the guide bar is provided with a saw chain 17 driven by the power saw motor via a driving wheel, not shown, and with two through-holes 18,19. One of the holes 19 is located at a point spaced somewhat inwardly from the free end of the guide bar whereas the other hole 18 is located at a point spaced a corresponding distance from the opposite guide-bar end, which end is fixedly mounted in the motor casing 20. The second hole 18 is likewise used to tension the saw chain in the event of slack that might arise during operation. More precisely, the second part consists of a worktable 21 in the form of a hollow square-section bar and of a clamping means 22 secured to the worktable by means of a bolted joint and serving to clamp the power saw guide bar to the worktable. In

addition, the worktable is provided with two indexing pins 23,24 positioned on the guide bar so as to ensure that the guide bar will be located in an optimum position on the worktable when the holes 18 and 19 are placed on top of the pins 23 and 24, respectively. The clamping means 22 is a clamp having a circular body 25 of abutment for abutment against the upper face of the guide bar and an operating lever 26 by means of which the abutment body is actuated to clamp the guide bar against the worktable.

Furthermore, two pivot pins 27 and 28 rotationally connect the worktable 21 to the first part 2, said pins mounted in their respective one of attachment plates 29 and 30, said plates in turn welded to the L-shaped beam 8. One 29 of the attachment plates is also formed with a longitudinally extending groove 31 wherein is guided a locking means in the form of a spring clamp 32, one end of which is fixedly secured to the L-shaped beam 8 and the opposite end of which supports a grip means in the shape of a knob 33. An indexing means in the form of an indexing disc 35 having recesses 34 formed therein is arranged in such a position on that end of the hollow square-section iron that is located in front of grooved attachment plate 29 that the leg of the spring clamp 32 may be brought into engagement with one of the recesses in the plate. The recesses are positioned on the indexing disc in positions ensuring that the guide bar, and consequently the power saw, may be secured in a number of predetermined, fixed angular positions. The indexing disc has at least three recesses, allowing the power saw to be placed in one horizontal position, see Fig 1, and two vertical positions, see Fig 2, wherein one of the vertical positions is shown. As appears clearly from Fig 2, the indexing disc 35 of the shown embodiment is

provided with two additional recesses 34 to make possible two extra fixed angular positions intermediate the horizontal position and the respective vertical positions.

When the power saw continually needs refuelling during felling operations in the woods, the fuel supply is most conveniently performed by the operator positioning the support member of the device in such a manner that the support legs thereof abut against a suitable tree trunk at such a level above ground that the operator may perform the maintenance work while in a standing position. He may then fix the support legs in position against the tree by means of the fastening means 5. The chain 10 is then placed in the recess of the attachment element in such a position that it abuts against the tree, whereupon the operator tensions the chain by turning the rotary disc 11 by means of the operating lever 13, locking it by over-centre locking.

When the first part 2 is fastened to the tree trunk the second part 14 is applied in a position to ensure that the face of the worktable 21 that is provided with the indexing pins 23 and 24 assumes its horizontal position. If the worktable does not assume its horizontal position from the start, it is made to assume this position by being rotated into a suitable angular position, following release of the spring clamp 32, which is effected by forcing the spring leg in a direction towards the L-shaped beam 8 and against the spring action, whereby the spring leg disengages from the indexing-disc recess wherein it engages when the turning movement is to start. When the worktable has been turned sufficiently to position the spring clamp above another recess in the indexing disc, the operator releases the

grip means 33, whereby the clamp spring owing to its inherent springiness moves into engagement with that recess and thereafter prevents the worktable from turning further.

The operator then places the power-saw guide bar 16 on the worktable while ensuring that the guide bar holes 18 and 19, respectively, are positioned above the pins 23 and 24, respectively, whereupon the guide bar is fixedly clamped to the worktable by means of the abutment body 25 of the clamp 22 in response to actuation of the operating lever 26. Once the power saw is supported by the device in the manner indicated, the device may be refuelled in a simple and convenient manner by the operator pouring gasoline into the power saw fuel tank, after having removed the tank lid 36. When the power saw assumes this position, it is also easy to supply oil for lubrication of the saw chain.

On the other hand, if sharpening of the saw chain is desired, the operator turns the power saw and the guide bar thereof over 90° clockwise and thereafter over 90° counter-clockwise, see Fig 2, relative to the horizontal position, in order to make it possible to work on the chain in a convenient manner. In order to allow the power saw to be turned, the operator again releases the clamp spring 32 by forcing its leg in the direction towards the L-shaped beam 8, the leg thus disengaging from the above- mentioned recesses. When the worktable has been turned over 90°, the clamp spring is placed on top of another one of the recesses of the indexing disc, whereupon the operator releases the grip means 33 in response to which the clamp spring, owing to its inherent springiness, will move into engagement with the recess in front and thereafter it prevents continued turning movement of the

worktable. After sharpening of the saw teeth of the saw chain that form an angle of +35° relative to the vertical plane, the so called left hand saw teeth, the operator rotates the guide bar over 180° after having released the clamp spring, such the chain saw teeth that form an angle of-35° to the vertical plane, the so called right hand saw teeth, are also placed in a position allowing them to be sharpened in a simple and convenient manner.

It is easily understood that a number of modifications of the above embodiment of the invention are possible within the scope of the appended claims. The clamping means, for example, may be designed as a clamping finger means having an abutment body of frusto- conical shape instead of as a clamp 22 having a circular abutment body 25. Should be guide bar be formed without through-holes, the indexing pins 23,24 and the clamp 22 are removed from the worktable and are replaced by a clamping means comprising two abutment bodies. The clamping means could also be configured in such manner that instead of abutting against the upper face of the guide bar it is able to grip the saw chain itself, an arrangement which does, however eliminates the possibility of sharpening the section of the chain that engages the clamping means. The fastening means could consist of two conventional tensioning belts, which after being joined together may be tensioned by means of a belt stretcher instead of by the chain 10 and the rotary disc 11. The support member 4 could consist of a U-shaped beam instead of by two yoke-shaped support sections 6,7, in which case the legs of the U-beam have a stepped configuration in order to allow them to be applied in abutment against the supporting tree trunk. It is

likewise possible to attach various tools, such as round files, socket spanners and the like on the first part 2, in which case the inventive device could also serve as a tool holder. If the device is to be used for example to temporarily support and secure a brush saw instead of a power saw, the clamping means is to be a clamp having a concave abutment body. In this case, also the clamping means will clamp different parts of the brush saw to the worktable during different operational steps. For example, the saw blade of the brush saw is clamped to the worktable if the saw teeth are to be sharpened while its handle/shank is clamped when refuelling is required, and so on.

In analogy of the above, also other types of tools may by clamped in position by the clamping means, if needed after professional adaptation of the abutment body of the clamping means.

It may likewise be possible to apply to the worktable 21 for instance a vice in order thus to obtain a provisional work place in the woods. The vice is then configured in an expert manner, to allow it to be clamped by means of the clamping means.