SAW WIRE

Abstract: A saw wire according to the invention has two parallel wire strings having a number of saw elements evenly distributed along the wire strings. A saw element comprises a platform (1) and a cutting plate (2). The platform (1) has both two grooves or cut-outs (5, 6) intended to receive two parallel wire strings (3, 4) and a groove (8) which is open towards the bottom to receive driving wheel and pulley.

Description: Saw wire. This invention is for a saw wire which may be used for sawing of stone, concrete and similar materials and also for of wood, plastics etc. The saw wire is primarily intended for hand-held motor driven saws but it may also be used with stationary and other equipment. Sawing of stone and concrete occurs at building activities, often at rebuilding e.g. for making openings for doors and windows. In the same operation there may be sawing of several different materials, e.g. wood, concrete and reinforcements rods. For this kind of sawing it is known to make use of saws having large, circular cutting blades. The use of hand held motor driven saws having saw blades and chains is also known. In all of these case special problems occur, among other reasons because the materials are very hard and cause a considerable wear of the active surfaces of the saw chains and other equipment. Circular saw-blades also cause a considerable "over saw" beyond the required dimensions of the opening. There are also problems with the adaptation of the distribution of cogs in the case of saws having power driven chains or the like. There is a need for continuous lubrication of the chain in order to reduce the wearing of moving parts and reduce the friction in contact with the saw blade. The present invention is for a saw wire by means of which the said disadvantages may be wholly or partly eliminated. The saw wire of the invention also enables comparatively narrow cuts the width of which is constant and does not change due to the wear during the sawing. A saw wire according to the invention has the characteristics which are mentioned in claim 1. Embodiments of the invention has the characteristics which are mentioned in the subclaims. The invention will below be described more in detail with reference to the embodiments which are shown in the enclosed figures. Figure 1 shows a platform having an cutting plate fixed upon it forming a saw element. Figure 2 shows a part of a saw wire, partly in cross section. Figures 3 and 4 show an alternative embodiment of a saw element. Figure 5 shows a cross section of a pulley and an interacting saw element. Figure 6 shows, partly in cross section, a part of a saw wire. Figure 7 shows a hand-held motor driven saw having a saw wire according to the invention. Figure 8 shows saw blade, pulley and saw wire in cross section. A saw wire according to the invention has two parallel strings of wire having a number of saw elements evenly distributed along the wires. The saw element shown in figure 1 includes a platform 1 and a cutting plate 2, which is arranged on the top of the platform and attached thereto. The platform 1 has both two cut-outs or grooves 5, 6 which are open to the sides and which surround two parallel strings of wire 3, 4 and a groove 8 which is intended to receive pulley or drive wheels. Preferably the groove 8 extends itself so far towards the surface for mounting of the cutting plate on the platform that it is at least as close to this surface as the side grooves 5, 6. The two equally long wires 3, 4 form endless loops which are parallel with each other and carry a number of saw elements evenly distributed along the wires. The strings of wire are arranged at a distance from each other, one outside each of the planes of the sides of the pulley and drive wheels and it is preferred that the wires run along the outside of the periphery part of the pulley 13. The free space between and within the saw elements is preferably wholly or partly filled with a filler 7. This is preferably made from elastic material, for example urethane rubber, and it adheres to the contacting surfaces of the wires and saw elements of the saw wire keeping them together. It is convenient that the filler does not extend itself all the way up to the upper surface of the cutting plates but stops a few millimetres below these surfaces. The cutting plate 2 is mounted onto the top surface of the platform 1. The cutting plate is a little wider than the platform, preferably about 0.5 mm wider, the width of the cutting plate is to be understood as the width at right angle to the lengthwise extension of the saw wire. If the cutting plate 2 is narrower than the platform 1 the sawed cut out will be narrower than the platform which brings with it that the saw wire will get caught or be severely worn at its sides. An alternative embodiment of a saw element is shown in figures 3 and 4. The grooves in the platform for receiving of wires and wheels are 0 than somewhat differently designed and the cutting plate is wider than the platform. In the figures there are no special means shown for the fastening of the cutting plates on the platforms. The fastening may be by means of soldering or in any other suitable way and also fasteners may be used. The cutting substance of the cutting plates is selected with consideration of its intended use. For hard materials the cutting plate may contain diamond or crushed hard metal and be made by sintering or electroplating, for softer materials plates with ground cutting edges may be used. Parts of a saw wire are shown in figures 2 and 6, in perspective view and in cross section along a part of its length. The number of saw elements of a saw wire may vary within wide limits, usually between 50-150 units for hand-held equipment. The inclusion of a saw wire in a hand-held motor saw is shown in the figures 5, 7 and 8. The motor saw is of a generally state of the art design having a motor housing 9, two handles 10, 11 and a saw blade 12. The saw blade has at least in its front section two shanks 17, 18 between which there is a shaft 14 which carries the front pulley 13. This may in known manner be adjustable to be accommodated to the length of individual saw wires an conditions of use. Inside the motor housing and not shown in the figure there is a corresponding driving wheel which at the part which is in contact with the saw wire has the same cross section profile as the pulley 13. However, the driving wheel may be of a different diameter. Both the driving wheel and the pulley 13 have smooth circumferences without cogs, teeth or the like means for the driving of the wire, in other embodiments of the invention the driving wheel may be so designed that it bears on the whole of the underside of the wire. The driving wheel may also be made as a V-belt wheel and the saw wire is then suitably adapted to the driving wheel. In order to further increase the friction between the driving wheel and the wire the wire may in some embodiments be forced against the driving wheel by means of a pulley or otherwise. The wire is driven thereby that the friction in the contact with the driving wheel is so great that there is hardly any slipping. The wire is tensioned and self- supporting between the wheel and the pulley without contact with the saw blade or any other supporting surface so there is no need for lubrication.

Claims: CLAIMS. 1. Saw wire for a motor saw having an extending saw blade and including pulley and driving wheel around which the endless saw wire is arranged and carries several cutting elements which are wider than the saw blade and evenly distributed along the saw wire characterized therein that the saw wire comprises two parallel wire strings between which there are platforms which are carried by the wires and on their upper surfaces carry cutting plates, that the cutting plates in their bottom surface have grooves or cut-outs intended to receive the outer circumference of the pulley and the driving wheel and that the wire strings are positioned at a distance from each other, one outside each of the side surface planes of the pulley and the driving wheel. 2. Saw wire according to claim 1 characterized therein that the wire strings are so mounted into the platforms that the grooves for the pulley and the driving wheel extend themselves closer to the cutting plates than the wire strings. 3. Saw wire according to any of the preceding claims characterized therein that the surface which is in contact with the driving wheel is essentially smooth without cogs or other driving means. 4. Saw wire according to any of the preceding claims characterized therein that the platforms are agglomerated into one unit. 5. Saw for stone or concrete using the saw wire of any of the preceding claims characterized therein that the pulley and the driving wheel have smooth, circular circumferences without cut-outs, cogs or the like means. 6. Saw according to claim 4 characterized therein that the saw wire is self-supporting between the pulley and the driving wheel.

Inventors: SVENSSON ANDERS, SVENSSON, ANDERS
Applicants: HAGBY ASAHI AB, SVENSSON ANDERS, SVENSSON, ANDERS
Application year: 1999
Main classification: B23D61
IPC codes: B23D57, B23D61, B28D1