WO1989012522A1

WO1989012522A1 - Saw-scissors

Info

Publication number: WO1989012522A1
Application number: PCT/NL1989/000045
Authority: WO
Inventors: Bernardus Johannus Maria Olde-Heuvel
Original assignee: Coöperatieve Vereniging "Dutch Tools" U.A.
Priority date: 1988-06-13
Filing date: 1989-06-07
Publication date: 1989-12-28
Also published as: EP0386177A1

Abstract

A movable, in any case hollow shaft (6) has been fitted in a body (1) clear off the wall by means of one or more bearings. Clear off the wall of the hollow shaft (6) a solid shaft, or for the purpose of saving weight, a hollow shaft (3) has been fitted in by means of one or more bearings. Both on the hollow shaft (6) and on the other shaft (3) a gear wheel has been installed. Both gear wheels (2 and 4) have an equal number of teeth. The insertion of one or more planet gear wheels between the gear wheels (2 and 4) makes the apparatus capable of achieving a reverse turning direction between the shafts (3 and 6). In the situation as it is shown the number of drives by the saw blades (8 and 9) depends directly and exclusively on the number of drives performed by the propulsion engine connected to the shaft (3) of the saw-scissors. The saw blades (8 and 9) are of an equal diameter and have similar positions of the teeth (10 and 11). The exterior saw blade (9) fitted on the interior shaft (3) and left turning in the given situation (so not clock-wise) has a position of the teeth to the effect that the teeth (10) bite into the object to be sawn. The interior saw blade (8), fitted on the hollow shaft (6) and right turning in the given situation, (so clock-wise), also has a position of the teeth to the effect that these teeth (11) bite into the object to be sawn. The teeth of both the exterior blade (9) and the interior blade (8) are placed in an alternating position which means that one tooth (10 or 11) cuts the object to be sawn in perpendicular position, whereas the tooth (10 or 11) following next cuts the surface to be sawn from a certain angle to the saw blade, which angle is to be chosen and adjusted per object. The position of the teeth mentioned above results in and reinforces the combination of cutting and sawing as wanted.

Description

SAW-SCISSORS

The invention relates to an apparatus to saw and cut materials and is mostly carried out in plate material, having cutting parts attached to the shaft of a propulsion engine, the whole construction being carried out as a whole. The well-known Dutch document number 7702467, which is open to public, is titled : "Cutting apparatus with a number of rotating disk-like parting tools". It refers to a construction with a number of rotating disk-like parting tools fitted up near to one another and shaped like wings consisting of more than one part, fitted on a supporting beam and gearing into one another without touching one another and driven synchronously again and again in reverse directions.

This apparatus has the handicap that the wings consisting of more than one part with a sawing contour can gear into the plate material in a very irregular and floundering way which results in an irregular, badly performed cut in the plate material. One thing and another leads to the fact that this well-known apparatus cannot be used as a hand tool.

The construction of the present invention aims at raising the disadvantages mentioned above in such a way that the tool contains at least two cutting parts with a continuous contour that are coaxially fitted near to each other and which parts are driven by means of two shafts, the one coaxially placed into the other, to the effect that one shaft is connected to the other by inserting a mechanism to reverse the turning direction in between.

Another new development occurring in this invention is the phenomenon that the cutting parts appear to be disks and that these disks appear to be circular saws. This advantage together with the characteristic of claim 1. is an improvement of the act of sawing with for example a circular saw to the effect that the object need not be clenched and that on the contrary, putting it extremely, it can stay there loose, and that sawing and cutting are being performed in a combined action. The safety of the act of sawing is thus highly increased. The fact that the cut needs no or hardly any further treatment as to possible wire edges is another advantage.

The working of the saw-scissors is based on the combination of sawing and cutting, which are in itself generally well-known principles. The present combination of these two techniques for parting materials is based on the application of two saw blades with identical diameters and with identical teeth moving in reverse directions, which blades perform their action as near to each other as possible. The space in between the saw blades is kept as small as possible for several reasons, mainly and in the first place in order to prevent sawdust from getting between the blades which might result in the machine getting stuck and in the second place in order to achieve that the .width of the cut is kept as small as possible. A further surprising property of the saw in question is it being a very safe procedure. The fact that the saw blades move at the same or nearly the same speed, however in reverse directions, makes the sawing action produce a rafter to the result that these two rafters neutralize each other completely or almost completely. While performing the act of sawing the operator will feel no or hardly any resistance which will always be felt while handling a circular saw which will

^•always develop resistant forces during the action. Theoratically, and when handled correctly also in practice, the cutting of the object may be performed while leaving it unclenched, so completely loose. Moreover has the apparatus been further developed, according to the invention, in such a way that the mechanism for reversing the turning direction consists of two conical gear wheels and at least one planet wheel and that the shaft is running right through the center of the conical gear wheels falls together with the shaft of the propulsion engine and that the propulsion engine may be either electric or pneumatic.

The advantage lies in the fact that there is a hollow tube having on the one side a thickening where a gear wheel construction can be fitted and on the other side an exit for two shafts placed in the tube. The shaft construction contains a hollows shaft in which a second shaft is fitted in which need not necessarily be hollow. Both shafts are placed into one another by means of one or more bearings and in its turn the exterior shaft is fitted in the hollow tube by means of one or more bearings. The shafts are both separately fixed on a gear wheel with an equal number of teeth. One or more planet wheels make the shafts turn in reverse directions, as it is meant to be performed in order to achieve the working principle of the saw-scissors, namely to saw an object without the necessity of clenching it and to prevent the occurrence of wire edges on one of the two cuts as much as possible.

Besides has the invention resulted in a further development of the apparatus to the effect that the shaft passing right through the center of the planet wheel falls together with the shaft of the propulsion engine.

The advantage lies in the fact that the cut is made in the direction of the longitudinal axis of the saw-scissors, which makes it an even more suitable handtool for certain applications. A further development of the construction according to the invention has resulted in the two coaxial shafts and the surrounding body of the apparatus being made of a flexible material. The reason is that for certain applications it is necessary to carry out part of the body and part of the two shafts flexibly. This case occurs when the tools get too voluminous to saw at the spot itself and yet a cut must be made there. In this case the saw-scissors offers extra high safety because those locations will generally offer the operator little room to manoeuvre so that the absence of resistant forces is very important. The saw-scissors can saw or cut any material such as several kinds of wood, stone, metal or synthetic material, because in principle it all depends exclusively on the material to be sawn, the moving speed, and the sawing teeth along the material to be sawn and the saw blades themselves.

Then there is another development of the apparatus according to the invention resulting in the fact that the disks are smooth and are sharpened knife-wise along the circumference. The intention is to have the opportunity to apply smooth cutting blades that are sharpened on one side, on the analogy of for instance cutting machines for sausage and meat products, as placed in butcher shops. When applying the saw-scissors for these kind of purposes it may be necessary to have a rotating knife. In this case too it is safer to use the saw-scissors in view of the compensation of resistant forces.

A drawing of this invention is enclosed in order to illustrate the contents of this document. This drawing exclusively refers to the simplest version of the saw-scissors without propulsion. The drawing shows:

Figure 1. : a sketch in perspective of the working principle of the saw-scissors in which the propulsion is omitted. Figure 2. : a sketch of the two saw blades

Figure 3. : a section view of the saw-scissors in order to illustrate the working principle of the type that is being driven by for example a hand drill. In Figure 1. the working principle of the saw-scissors is shown for the situation in which it is made use of external propulsion like for instance a drilling machine. A movable, in any case hollow shaft (6) has been fitted in the body (1> clear off the wall by means of one or more bearings. Clear off the wall of the hollow shaft (6) a solid shaft, or for the purpose of saving weight, a hollow shaft (3) has been fitted in by means of one or more bearings. The drawing does not illustrate that part of the body (1) and of the two shafts (3 and 6) can be made flexible. Both on the hollow shaft (6) and on the other shaft (3) a gear wheel has been installed. Both gear wheels (2 and 4) have an equal number of teeth. The insertion of one or more planet gear wheels between the gear wheels (2 and 4) makes the apparatus capable of achieving a reverse turning direction between the shafts (3 and 6). In the situation as it is shown the number of drives by the saw blades (8 and 9) depends directly and exclusively on the number of drives performed by the propulsion engine connected to the shaft (3) of the saw-scissors. In the case of propulsion by means of a planet wheel, which type is not described and illustrated in this document, the number of drives by the saw blades (8 and 9) may be influenced by the number of teeth on the planet wheel (5). Thus it is possible to have the saw blades along the longitudinal axis as indicate in "versus". The choice of the materials used for the manufacture of the different parts of the saw-scissors mainly depends on the purpose for which the tool is to be used. In some case light materials such as (technical) synthetic materials, light metals or anything alike and in other cases one may prefer to choose steel or other heavy materials of this kind.

Figure 2. gives an impression of a possible position of the teeth on the saw blades (8 and 9). The saw blades (8 and 9) are of an equal diameter and have similar positions of the teeth (10 and 11). The exterior saw blade (9) fitted on the interior shaft (3) and left turning in the given situation (so not clock-wise) has a position of the teeth to the effect that the teeth (10) bite into the object to be sawn. The interior saw blade (8), fitted on the hollow shaft (6) and right turning in the given situation, (so clock-wise), also has a position of the teeth to the effect that these teeth (11) bite into the object to be sawn. The teeth of both the exterior blade (9) and the interior blade (8) are placed in an alternating position which means that one tooth (10 or 11) cuts the object to be sawn in perpendicular position, whereas the tooth (10 or 11) following next cuts the surface to be sawn from a certain angle to the saw blade, which angle is to be chosen and adjusted per object. The position of the teeth mentioned above results in and reinforces the combination of cutting and sawing as wanted. The tooth (10 and 11) off the saw blades take care of the removal of chips and a cut of sufficient width in order to prevent the saw blades (8 and 9) from getting stuck, all in analogy with the normal position of teeth on saw blades. Contrary to the usual position of teeth on the saw blades is the position of teeth (10 and 11) off the surface of the saw blades (8 and 9) only in one direction here, that is to say the direction turning away from the other saw blade (respectively 9 and 8). The frequency of the teeth will not in all cases be the same as described here. The position of the teeth also depends on the saw blades and the material to be sawn.

For special applications the saw blades can be delivered as rotating knives as used in the meat business for example. In this case there will be no teeth and will the knives only be sharpened on one side to the effect that, when looked at from the knife-side, and in this case across the knife blades where they lie next to one another, a sharp V-form is seen, which also appears on the rotating knives of the cutting machines already mentioned.

Figure 3. shows a cross section of the saw-scissors in order to illustrate the technical details. Here too is taken into account that the propulsion is done externally on the shaft (3). In the example in question a tooth wheel is fitted upon the central shaft (3) by means of a pin connection (14). This shaft tunnels through the hollow shaft (6) and is fitted there by means of a bearing (7) in the hollow shaft (6) near the tooth wheel, and by means of a second bearing (12) at the end of the hollow shaft (6), at the spot where the hollow shaft (6) is fitted in the body (1) by means of bearings (13). On the central shaft (3), protruding from the hollow shaft at its end, a breast and a screw thread are fixed.

The saw blade (9) is shoven on the screw thread and attached with the screw (18).

A second hollow shaft (6) is fitted around the central shaft (3). This shaft (6) is attached to a tooth wheel (2) by means of a pin connection (14). The shaft (6) is fixed at the beginning of the narrowing of the body (1) and at the end of the body (1) by means of two bearings (12). On the hollow shaft (6) too, protruding from the body on one side, a breast and screw thread have been attached too. The saw blade (8) is shoven on this screw thread and fixed with a screw.

The body is constructed in such a way that the parts described above can be placed in it and that it also acts as a safety device against any touch of the rotating shaft. The Figure does not show the other end of the body since this is completely similar to the usual connections of accessories of drilling machines, in this patent specification the propulsion of the saw-scissors. For other applications of the saw-scissors, which are not described here, other ends of the body, adjusted to the type of propulsion, are needed. A handle (19) is attached to the body (1), hich in this example also serves as a bearing holder for the shaft (15) of the planet wheel (5). The shaft (15) of the planet wheel (5) in the body (1) is fitted by means of bearings in such a way that the gear wheel (4), which is driven by the shaft (3) sets the planet wheel (5) in motion. The planet wheel (5) in its turn sets the gear wheel in motion, thus bringing about the reverse turning of the hollow shaft (6), as known already.

Claims

CLAIMS :

1. Apparatus to saw and cut materials, mostly plates, having cutting parts attached to the shaft of a propulsion engine, ^"the construction being carried out as a whole with the characteristic that the instrument contains at least two cutting parts having a continuous circumference, which are coaxially fitted near to one another and which parts are driven by means of two tube shafts (3,6), the one fitted into the other, and one shaft being connected to the other by the insertion of a mechanism to reverse the turning direction.

2. Apparatus according to claim 1, with the characteristic that the cutting parts are disks (8,9).

3> Apparatus according to claim 2, with the characteristic that the disks are circular saws (8,9).

4. Apparatus according to claim 2, with the characteristic that the disks are smooth and sharpened like knives around the circumference.

5. Apparatus according to claim 2, with the characteristic that the disks are abrasive disks.

6. Apparatus according to claim 1, with the characteristic that the interior tube shaft (3) of the two tube shafts (3 and 6) coaxially fitted into one another has a solid cross section.

7. Apparatus according to claim 1, with the characteristic that the mechanism for reversing the turning direction consists of two conical gear wheels (2,4) and at least one planet wheel (5).

8. Apparatus according to claim 7, with the characteristic that the shaft that tunnels right through the center of the conical gear wheel(((5) falls together with the shaft (20) of the propulsion engine.

9. Apparatus according to claim 7, with the characteristic that the shaft that tunnels right trough the center of the planet wheel (5) falls together with the shaft (20) of the propulsion engine.

5

10. Apparatus according to claim 1, with the characteristic that the propulsion engine may be either electric or pneumatic.

11. Apparatus according to the claims 1 and 10, with the 10 characteristic that the propulsion engine can be adjusted fluently.

12. Apparatus according to claim 1, with the characteristic that the two coaxial shafts (3,6) and the surrounding body (1) are

15 made of a flexible material.

13. Apparatus according to claim 12, with the characteristic that the flexible material is synthetic.

20 14. Apparatus according to claim 13, with the characteristic that the synthetic material is reinforced by fibres.