The invention relates to a saw guided by hand with an annular saw blade and a saw blade drive, which saw blade drive is driven through a friction wheel and a drive pinion on a gear shaft by a drive wheel engaging into the drive pinion on a drive shaft disposed in parallel and by a high speed electrical motor to be coupled to the drive shaft.
A ring-shaped blade of a circular saw and a ring saw with saw blade drive is known from the German printed patent document DE 690 03 593 T2, wherein the ring-shaped saw blade is equipped with at least one ring-shaped drive face made of a flexible, polymeric, solid material and wherein a rotating drive member can be pressed against the ring-shaped drive face in order to effect the rotation of the saw blade around its rotation center. Here the flexible polymeric solid material forms an inner edge part of the saw blade or at least one layer on a side of the web section of the saw ring, or the layer at least on one side of an inner edge part of the saw ring. Furthermore the document teaches a circular ring saw, which comprises rotating drive members, which are furnished with projections, which can be pressed into the flexible material of the saw blade, wherein the projections are furnished in a circumferential groove of a drive disk, and wherein the edge part of the inner circumference of the saw ring, which comprises the flexible material, can be received in the groove. According to a second variation, a drive wheel is furnished with projections, which projections can be pressed into a layer of the flexible material in the web section region of the saw blade. This form of the transfer of the rotary motion from a hydraulic motor onto the ring saw blade of a circular ring saw is problematical, since the inner edge part of the saw ring consists of rubber. This inner edge part is disposed by vulcanization at the inner circumference of the saw ring made of steel. The edge part made of rubber snaps into the circumferential groove of the drive wheel, into which drive wheel the projections are brought in. In this manner, the rubber is pressed wave shaped around the projections into the groove and is to transfer the rotating motion of the motor onto the ring saw blade through this route. The rubber is subject to a very high wear, and the saw rings have to be frequently exchanged for this reason.
The functioning of these transmission variations is very doubtful when high speed motors are employed, but at least cost intensive for the production as well as the maintenance and repair. Also the groove disposed in the one flank of the saw ring, which is furnished for snapping of guide rollers, does not represent a large support for the otherwise expensive drive system.
A drive wheel for the eccentric drive of the saw blade is known from the international printed patent document WO 98/58 757. The drive wheel comprises a carrier part which is seated immediately on the drive axis. A drive ring with a groove on the circumferential side is disposed on an inner collar of the carrier part, wherein the inner edge of the ring saw blade engages the carrier part. The carrier part with the drive ring is directly connected to the drive axle of the motor through an accessory plate and through further conventional connection parts. A circular groove is disposed in a flank of the saw ring, wherein two guide rollers engage in the circular groove and the rollers subjected to spring tension together with the counter holding support rollers press the ring saw blade against the drive wheel. The support of the guide rollers in a groove of the saw ring has to assure the total radial press-on pressure of the saw ring into the drive wheel, which leads to a quick wear of the groove and of the roller rings. Thereafter, the rollers have to be frequently exchanged. The drive wheel placed under protection is expensive based on its many parts during mounting and in a required exchange of the same.
Therefore, it was an object to find a ring-shaped saw blade and a therewith associated saw blade drive as an easily exchangeable tool preset for a saw guided by hand, wherein the saw guided by hand is characterized by high stability, low weight proper, high flexibility as well as high precision and is suitable for an easy to handle and quick connection with the high speed compact and hand guided electrical drive unit.
This object is resolved by a ring-shaped saw blade and an associated saw blade drive with the features of claim 1.
It is to be emphasized that the annular saw blade according to be present invention and the saw ring drive at characterized by a ring-shaped saw blade, wherein on two sides of the inner circumferential face there is exhibited a circular shaped disposed flank toothing, which runs on two sides in a radial direction from an inner front face to an outer front face and wherein the ring-shaped saw blade with its two side flank toothing engages into a front side groove of an eccentrically disposed friction wheel, wherein the oppositely disposed groove faces of the friction wheel are also furnished with a flank toothing in each case, which engage in the flank toothings of the ring-shaped saw blade and wherein the saw blade drive exhibits a drive wheel on a drive shaft, a drive pinion, and exhibits a friction wheel on a gear shaft disposed parallel to the drive shaft, and wherein the rotary motion of the drive machine is to be transferred through the drive wheel of the drive shaft onto the drive pinion and the friction wheel on the gear shaft as well as from the friction wheel to the ring-shaped saw blade. The construction of the ring-shaped saw blade and of the saw blade drive pressure assures a stable force transmission over the flank toothings engaging into each other of the transmission parts. Based on the gear drive intermediate disposed between the drive shaft and the drive wheel and the friction wheel on the gear shaft and its translation, the ring-shaped saw blade and the friction wheel are substantially unloaded with respect to the required radial press-on pressure of the ring-shaped saw blade against the friction wheel.
It is particularly advantageous that the high stability of the flank toothings engaging into each other of the ring-shaped saw blade and of the friction wheel, according to claim 2, is accomplished by the formation of recesses in the inner circumferential faces on two sides and in the inner faces of the front side groove of the friction wheel. The stable force transmission from the friction wheel to the ring-shaped saw blade is in addition supported by the constructively clear formation of the friction wheel according to claim 3, which formation is assured by the force matching and disengageable connection of two disks, wherein the two disks form a groove at their outer circumference, wherein flank toothings a form in the oppositely disposed longitudinal sides of the groove, wherein the flank toothings form a counter toothing to the flank toothing of the ring-shaped saw blade, wherein the friction wheel supported on the gear shaft is guided, according to claim 8, between the inner front face of the ring-shaped saw blade (1) and a recess in the outer circumference of a guide sheet metal.
The guide rollers, according to claim 4, according to the present invention have to be emphasized, wherein the guide rollers exhibit at least three ring-shaped noses at their circumferential faces, wherein the noses engage into the at least three grooves disposed on one side of the internal circumferential face of the ring-shaped saw blade. The support rollers disposed oppositely to the guide rollers and having at least three grooves and four pressure faces, are laid down with the pressure faces at the planar side of the internal circumferential face of the ring-shaped saw blade and the support rollers stabilize in this way the guiding of the ring-shaped saw blade.
The constructive formation of the guide rollers and the support rollers, according to
A further advantage according to the claims 5 through 7 comprises that the flank toothings of the ring-shaped saw blade and of the friction wheel can be performed as an involute toothing or as a round toothing, wherein the teeth of the flank toothings formed on two sides in the inner circumferential face of the ring-shaped saw blade and the teeth of the flank toothings formed into the oppositely disposed inner faces of the friction wheel can be disposed at equal distances or staggered. This leads to a higher flexibility and stability of the saw blade drive.
The invention is described in more detail in the following by way of two embodiment examples. The drawings show here in
According to a second embodiment example shown in
1. Ring-shaped saw blade,
1.1 Outer circumferential face of the saw blade,
1.2 Inner circumferential face of the saw blade,
2. Grooves in the saw blade,
3. Housing for the saw blade drive,
4. Support rollers (translator's remark: should be Guide rollers),
4.1 Ring-shaped noses,
4.2 Broken out rest faces,
4.3 Bearing bore hole,
5. Support rollers,
5.1 Ring-shaped grooves,
5.2 Ring-shaped press faces,
5.3 Broken out rest faces,
5.4 Bearing bore hole,
6. Saw blade drive,
6.1 Drive wheel,
6.2 Drive shaft,
6.3 Drive pinion,
6.4 Gear shaft,
7. Flank toothing at the saw blade,
7.1 Recesses of the flank toothing,
8. Friction wheel,
8.1 Circumferential groove,
8.2 Oppositely disposed faces of the circumferential groove,
8.3 Recesses of friction wheel,
8.4 Disks of the friction wheel,
9. Flank toothing,
10. Ring-shaped guide sheet metal,
10.1 Recess
Number | Date | Country | Kind |
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10 2010 004 604.3 | Jan 2010 | DE | national |