EP0328922A2 - Device for converting a manually operated circular saw - Google Patents

Abstract

In connection with a conversion set for a portable circular saw, which latter comprises a housing, an associated electric drive motor with output shaft and, if necessary, also a gear, and at least one handle, it is proposed to attach to the basic unit remaining after removal of the circular saw blade a chain-saw adapter attachment, to convert the portable circular saw in this manner into an electric chain saw and to secure the chain-saw adapter attachment in place by means of mechanical stops provided on a main bearing plate and coacting with the gear housing of the circular saw and, in the axial direction, by tightening a screw upon the output shaft of the circular saw projecting through the drive pinion for the saw chain.

Description

State of the art

The invention relates to a conversion device for a circular saw according to the preamble of claim 1.

Circular saws in the usual form, for example the type 6050/55 Kress of the applicant itself, which is particularly suitable for the purposes of the present invention, consist of a housing which supports an electric drive motor and, if appropriate, its gearbox, the power of the electric motor being relatively high compared to conventional electric hand tools , for example, can be located in the range of 1 kW. The housing also has handles for guiding the circular saw, the longitudinal axis of the driving electric motor running transversely to the direction of advance of the circular saw, so that the circular saw blade is placed on the output shaft stub in a rotationally fixed manner without a deflection gear and is usually secured by a retaining screw of a suitable shape and structure. At the bottom, such a circular saw has a saw foot, which can also be referred to as a saw table, and which can usually be changed on one side, both in terms of its distance from the housing, which changes the depth of cut of the circular saw, and can be tilted at predetermined angles, so that angular cuts are possible. Furthermore, it is possible through the foot or through guide means on the housing to use displaceable parallel stops, so that defined saw cuts can be carried out. Such circular saws are suitable for sawing boards and. Like., But a depth of cut of more than 20 to a maximum of 30 mm can rarely be achieved.

On the other hand, chain saws are known in many forms and designs, for example as chainsaws driven by an internal combustion engine or electric chain saws, which have the advantage of smoother running and easier handling, so that besides industrial use, such electric chain saws are also particularly good for private use, for example for preparing firewood, for sawing larger trees, etc. Like., Are suitable.

To convert electric hand tools, a variety of adapter devices u. Like. Known, wherein a particular system is that a motor of predetermined power with a suitable motor stop surface to different tool attachments or adapter arrangements can be set, for example by clicking, so that it is possible to drive a variety of individual tools by a common electric motor.

The possibility of converting a hand-held circular saw into an electric chain saw has not yet been recognized, mainly not because a hand-held circular saw comprises a large number of safety devices, mainly because of the comparatively high risk of injury associated with its handling, for example complete rigid, housing-fixed covering of the saw blade upwards and an additional pendulum protection hood, which also covers the saw blade when not in use and is increasingly folded away to the rear due to the material to be processed as the saw progresses. Electric chain saws also differ significantly from circular saws in their basic form; For example, the electric chain saw has a horizontally facing saw blade around which the chain runs; in a hand-held circular saw, this area is completely rigidly encapsulated, so that a conversion is not possible for this reason alone. Furthermore, when converting, i.e. converting a given hand tool into a second form of work, care must be taken that this conversion is not too complicated, especially for the private individual, since under these circumstances it is rather avoided and then rather not with the conversion kit in the present case So if a duo saw is used as a chainsaw. You then tend to forego the use of chainsaws or use two separate systems at significantly higher costs. It also happens in this context to the fact that after the conversion has been completed, the now new type of work equipment is not too different from the usual shape of a, in the present case a chainsaw, and furthermore, the converted tool must be fully usable, provided that at least the same safety requirements are met as with electric chain saws otherwise too.

The present invention is therefore based on the new object to provide a conversion device for a hand-held circular saw, which converts it into an electric chain saw that can be handled perfectly and with little effort.

Advantages of the invention

The conversion device according to the invention solves this problem with the characterizing features of the main claim and has the advantage that converting a conventional hand-held circular saw to an electric chain saw is possible in a matter of seconds, the electric chain saw created in this way fulfilling the same safety conditions as are normally placed on electric chain saws.

It is also advantageous that the conversion does not require disassembly or disassembly of the basic circular saw; it is only necessary to remove the circular saw blade, which makes the only screw that is required for the reassembly, namely the fastening screw for the circular saw blade, available. All that is then required is the chain saw adapter attachment attached to the handheld circular saw, which has been left unchanged, and after being pushed on of the chain sprocket on the output shaft to tighten this screw again. The conversion is then completely finished, and the electric chain saw is in a usable state, whereby additional advantages over conventional electric chain saws result from the fact that the circular saw foot is also unchanged in the new design.

This makes it possible to make angular cuts up to 45 °, since the adjustability of the circular saw foot remains unaffected; the circular saw foot can also be used to create a rip fence. The depth of cut with the chainsaw is only limited by the length of the chainsaw sword. The defined saw cuts that are now possible open up additional areas of application for such a duo saw, although, of course, a conventional use of such an electric chain saw, for example for preparing firewood, for sawing logs, felling trees and the like. Like. Is possible.

It is also advantageous that the chainsaw adapter attachment carries all components and individual parts required for the operation of the chainsaw; including an oil tank and the appropriate means to ensure that the chainsaw is properly lubricated and that it slides along the blade guide.

It is also advantageous that the usual pendulum protection hood can be retained during the conversion; it is only pushed back for the conversion; The saw blade is used as the main component of the new electric chain saw and is non-rotatable due to mechanical stops secured, whereupon then, as already mentioned, the entire adapter attachment is secured axially by fastening the shaft screw.

The measures listed in the subclaims permit advantageous developments and improvements of the conversion device specified in the main claim. Particularly advantageous is the construction of the adapter attachment for the chainsaw in the form of a main bearing plate facing the hand-held circular saw basic device, which at the same time carries the means for mechanical locking or locking and supports the chain pinion and the saw blade driven by the output shaft of the hand-held circular saw. At a distance from this main bearing plate there is a cover plate which stores the oil tank or merges into it in one piece and covers the parts located in the area of the drive pinion, so that, as is usual with electric chain saws, only the sword-guided working area of the saw chain is exposed in this case. A rear safety splitting wedge can make the electric chain saw structure even more reliable.

drawing

• Fig. 1 eine Seitenansicht einer üblichen Handkreissäge mit Sägefuß und zurückgeklappter Pendelschutzhaube;
• Fig. 2 eine Ansicht des Kettensägen-Adaptervorsatzes von vorn mit in der zeichnerischen Darstellung bewußt durchsichtig ausgeführter Abdeckplatte;
• Fig. 3 in vergrößerter Teildarstellung den Kettensägen-­Adaptervorsatz in Seitenansicht mit zum Teil geschnittener Darstellung;
• Fig. 4 den Kettensägen-Adaptervorsatz in einer Ansicht von hinten und
• Fig. 5 die zur Kettensäge umgebaute Handkreissäge (Duo-Säge).

An embodiment of the invention is shown in the drawing and is explained in more detail in the following description. Show it:

• Figure 1 is a side view of a conventional hand-held circular saw with a saw foot and a hinged protective hood folded back;
• Fig. 2 is a view of the chainsaw adapter attachment from the front with in the drawing deliberately transparent cover plate;
• Fig. 3 in an enlarged partial view of the chainsaw adapter attachment in side view with a partially sectioned representation;
• Fig. 4 shows the chainsaw adapter attachment in a view from behind and
• Fig. 5 the hand-held circular saw converted to a chainsaw (duo saw).

Description of the embodiments

The basic idea of the present invention is to convert a hand-held circular saw into an electromotive chain saw in that the sprocket driving the saw chain is placed and screwed directly onto the output shaft of the hand-held circular saw, which otherwise carries the circular saw blade, with a main bearing plate supporting the pinion being in a rotationally fixed position to the housing of the circular saw.

The hand-held circular saw 10 shown in FIG. 1 comprises an electric drive motor which cannot be seen in this view and which usually drives the circular saw blade (not shown) via an intermediate gear, which is held on the transmission output shaft by means of the saw blade holding flanges or spacers and a lock nut 41 . The basic structure of such a hand-held circular saw is completed by a saw foot 13 which has adjustment means 14a, 14b on both sides for setting the saw depth, making angular cuts or for receiving a rip fence at 15, and a conventional one Pendulum protection hood 16, which in the illustration shown in FIG. 1 is withdrawn up to a stop formed by a longitudinal projection 17, a small handle 18 allowing the pendulum protection hood to be rotated by manual intervention by the user.

Such a conventional hand-held circular saw 10 according to FIG. 1 is the starting device for converting to an electric chain saw, wherein only the saw blade fastened with the screw 12 can be removed; a job that can be carried out by any user of a circular saw and occasionally also has to be carried out, for example for sharpening, converting to a different tooth shape and. the like

The chain saw adapter attachment to be connected to the hand-held circular saw 10 in FIG. 1 is shown in FIG. 2 and designated by 20. An essential component of the adapter attachment 20 is a base plate or main bearing plate 21 (see FIG. 3), which supports the pinion 24 driving the saw chain 11 through a bearing 23 inserted in a central bore 22. The pinion is removed after removing the circular saw blade with its (one-piece) spindle 24 'on the shaft end 26 of the circular saw 10, wherein an inner flat drive can be formed on the spindle, so that it sits on the output shaft rotatably.

This completes the necessary fastening measures for the chainsaw adapter attachment, because the circular saw is locked in place to ensure that the adapter attachment is locked on the housing / motor / gearbox Drawings, not shown, stop, locking or securing means, which start from the main bearing plate 21 and form-fitting corresponding parts of the hand-held circular saw, preferably the facing gear housing. These locking means serving to prevent rotation between the hand-held circular saw basic device and the adapter attachment are also not shown, since their structure, structure and shape can be arbitrary per se and of course must be adapted to the particular type of hand-held circular saw.

In the preferred exemplary embodiment of the present invention, in which the chainsaw adapter attachment is attached to a circular saw of the 6050/55 Kress type, there is a first angle (not at the front) projecting to the right on the back of the main bearing plate, i.e. in the illustration of FIG. 3 shown), which can be an integral part of the main bearing plate or fastened to it in a suitable manner, for example screwed, and projects in the direction of the facing parts of the circular saw so that there is a support against rotation using the gear housing as a stop; preferably a second obliquely downward angle can be provided (not shown), which then forms a general U-shape with the first angle and encompasses the gear housing from the other side. These locking means then sit between the gear housing of the circular saw and the saw foot 13 and secure the main bearing plate and thus the entire adapter attachment, the main bearing plate being designed as an aluminum plate of suitable thickness. The chainsaw sword 27 is also fastened to the main bearing plate 21, specifically on a lower leg 28 projecting to the left in the plane of the drawing in FIG. 3. The leg 28 can have an opening 29 for the sword 27, in which the sword is inserted; the fixation takes place, for example, with the aid of two screws 30, which can be guided in the longitudinal holes of the sword for the longitudinal adjustability of the sword 27 and for tensioning the chain.

At a distance from the main bearing plate 21 there is a cover plate 31, which is fastened to the main bearing plate by means of spacing means which simultaneously determine the distance to the main bearing plate, for example spacer bolts. For example, three spacer bolts or other spacing means can be provided, which are composed of a chain catch bolt 32, a locking bolt or retaining pin 33 and a further spacer bolt 34, the chain catch bolt 32 and the further spacer bolt 34 each fulfilling dual tasks. The chain catch bolt, as its name suggests, also serves to catch a possibly tearing chain, so that it wraps around it and does not knock out, while the further spacer bolt 34 is also one of the two screws 34, 34 ', the hold and fix the safety riving knife 35 between the main bearing plate 21 and the cover plate 31.

Furthermore, the cover plate 31 carries the oil tank 36 required for lubricating the saw chain of the pinion and the sword sliding surfaces with an upper filler neck 36a; the oil tank 36 can be suitably attached to the Cover plate 31 may be attached; however, as in the exemplary embodiment shown, it can also be an integral part of the cover plate 31, for example welded to it.

Since the cover plate 31 must be designed to be removable from the main bearing plate 21, so that one has access to the saw chain and to the drive means located there, for example to remove or replace the saw chain for sharpening, the spacing means between the main bearing plate 21 and the cover plate 31 form detachable screw connections, a drip pipe 37 for the oiler is required for the conduction and transport of the oil. This drip pipe is fastened to the main bearing plate 21 and runs within a groove 38 in the main bearing plate which can be seen from the rear view in accordance with FIG. 4; the drip pipe then extends forward in the upper area according to FIG. 3 in the direction of the tank and can be inserted there into a tank outlet opening, for example sealed by an O-ring. At the lower end of the groove 38, the drip pipe then emerges again by passing through the main bearing plate and directing its end directly onto the sword guide and the chain driver. Suitable throttling means, not shown, in conjunction with the viscosity of the oil determine its flow rate (not shown).

It can be seen in particular from the illustration in FIG. 2 that the front cover plate 31, that is to say facing away from the hand-held circular saw basic device, has a larger area than the main bearing plate, so that it also the adjacent area, that is to say the area previously free for the circular saw blade in the basic circular saw device and also accommodates the small hand lever 18 of the pendulum protection hood 16 in a side slot opening 38, so that the latter is in its position in the retracted position when the device is converted to an electric chainsaw remains locked.

So that the sword position can be adjusted by actuating the screws 30 even without removing the front cover plate 31, this also has an edge recess 39 in the area of these screws.

In the preferred embodiment of the present invention sits in the receptacle of the inner ring of the ball bearing 23, which is received in the bore 22 of the main bearing bar 21, an integral with the pinion 24 receiving spindle 24 ', which with its inner flat driver 24a (see Fig. 4) is placed on the transmission output shaft.

The sword 27 has a deflecting star at the end opposite the driving pinion 24, which is not shown separately.

Such a construction of a chainsaw adapter attachment enables a very simple assembly on the basis of a conventional hand-held circular saw, in which after the circular saw blade has been removed, the saw foot is first set to a low depth of cut (stop), then the pendulum guard hood is pushed backwards and the adapter attachment with saw blade inserted from above and pressed onto the gear housing of the circular saw, whereby at the same time the transmission output shaft penetrates into the receiving spindle 24 'of the drive pinion; After inserting a spacer 40 (see FIG. 3), the locking screw 41 shown only partially in this figure is screwed and tightened onto the shaft end which then emerges freely on the other side of the pinion 24. The hand-held circular saw has now been converted into an electric chain saw and is now ready for use.

All features shown in the description, the following claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims (16)

1. conversion device for a hand-held circular saw, consisting of a housing, an electric drive motor with a motor shaft, possibly a gear, and at least one handle, characterized in that a supporting main bearing plate (21) is arranged on this for mounting a chainsaw adapter attachment (20) and rotatably attached to it the hand-held circular saw basic device (10) is attached and that a pinion (24) mounted on the main bearing plate (21) and driving the saw chain (11) is connected in a rotationally fixed manner to the output shaft of the hand-held circular saw basic device (10). 2. Conversion device according to claim 1, characterized in that the saw chain (11) driving pinion (24) passes through the output shaft of the hand-held circular saw basic device (10) and a screw is screwed onto the shaft stub projecting beyond the pinion (24) for sole use axial securing of the adapter attachment. 3. conversion device according to claim 1 or 2, characterized in that in addition to the screw of the chainsaw adapter attachment (20) via the output shaft passing through the pinion (24), the main bearing plate (21) of which is secured in a rotationally fixed manner by stops mechanically abutting the housing of the circular saw. 4. conversion device according to one of claims 1-3, characterized in that the main bearing plate (21) rotationally securing stops are formed by at least one protruding in the direction of the gear housing of the circular saw basic device angle. 5. conversion device according to claim 4, characterized in that a second, with the first angle forming a general U-shape angle is attached to the main bearing plate (21), which with the first angle, the adjacent gear housing of the circular saw basic device from at least two sides comprises and secures against rotation, the axial securing means being formed by the screw (41) screwed onto the output shaft passing through the pinion (24). 6. conversion device according to one of claims 1-5, characterized in that the main bearing plate (21) receives a bore (22) in which a bearing (ball bearing 23) is seated, which with a pinion (24) connected to the receiving spindle (24 ' ) is mounted, which is pushed onto the output shaft of the basic circular saw unit (10) for driving the pinion (24). 7. conversion device according to claim 6, characterized in that for the rotationally fixed connection of the receiving spindle to the output shaft, the receiving spindle an inside Flat entrainment with a correspondingly complementary shape of the output shaft. 8. conversion device according to one of claims 1-7, characterized in that the main bearing plate (21) the sword (27) of the chainsaw adapter attachment (20) and at the same time a front cover plate (31). 9. conversion device according to claim 8, characterized in that a lower cross leg (28) in an opening (29) receives the sword (27) and secures via at least one screw (30). 10. Modification device according to claim 9, characterized in that the at least one screw connection (30) for adjusting the sword (27) (chain tensioner) forms an elongated hole connection. 11. Modification device according to claim 8, characterized in that the cover plate (31) via distance means (32, 33, 34) is connected to the main bearing plate (21). 12. conversion device according to claim 11, characterized in that the spacing means are formed by a first, at the same time as a chain catch bolt, a second, at the same time at least partially fastening a safety riving knife (35) and a third spacer bolt (33). 13. conversion device according to claim 11, characterized net that the cover plate (31) stores an oil tank (36), from which a drip pipe connection (37) is guided up to the sword guide / chain driver. 14. conversion device according to claim 13, characterized in that the drip pipe (37) is inserted into a groove of the main bearing plate (31), with a transverse bend sealed in the outlet opening of the oil tank (36) attached to the cover plate (31) and with another lower bend conducts lubricating oil onto the sword guide. 15. Conversion device according to one of claims 1-14, characterized in that the front cover plate (31) has a lateral recess (38) into which a handle (18) engages when the pendulum guard hood is folded back and secures the pendulum guard hood in this position. 16. Modification device according to one of claims 1-15, characterized in that the saw base (13) retained on the circular saw basic device (10) serves the defined saw cut guidance (angular cuts, parallel cuts).

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