SE438466B - Controllable saw - Google Patents

Abstract

The invention refers to a saw, preferably for timber, constructed so that the saw is divided in two parts and that the saw teeth alternate matching one part or the other of the saw. Both parts of the saw are movable so that the cutting effect can bet varied in both parts of the saw. This allows the lateral force in the cut to be affected in the desired manner during sawing. The saw allows stabile straight sawing with a thin blade. Curved sawing can also be done.<IMAGE>

Description

10 15 20 25 30 7905412-8 thus greater effect on the path of the saw cut to the right or left.

If such an attitude is made in the right way, the preceding teeth get a counteracting effect against the forces emanating from e.g. the oblique texture of the saw object. The same effect can also be achieved if it the teeth of one saw group in the sawing direction are pushed before the other the teeth of the saw group.

A controlled increase / decrease of the cutting work / cutting force of the two separated tooth groups is performed on one or both of the following way. The word neutral position below means the position when they the two groups perform equal cutting work, ie the prevailing position since the mutual distances are equal between the teeth of the groups and the groups lie side by side in the sawing direction.

The invention is described in more detail in connection with the accompanying drawings.

Figures 1 and 2 show mutually pressed saw blades 1 and 2 with similar tooth pitch R and L.

Figures 3 and 4 show longitudinal sawing of a log.

Figures 5 and 6 schematically show the arrangement of a number of guide holes 16 in the central parts 7 and 10 of saw blades.

Figure 7 shows mechanical details for performing sawing the mutual displacement of the blades and thus the teeth.

Figure 8 shows the displacement of the teeth, 8b - 80 how the teeth R and L can be displaced along the connecting line between the teeth in relation to the neutral position 8a, 8d - 8e shows displacement in sawing direction and 8f offset in both directions.

Divide offset From the starting position, the mutual tooth distances change in one direction or another along the line between adjacent teeth. Thereby comes one or the other group of teeth to take over a larger part of the cutting work. _, __.-. ___.___.._ ..: _ ..-_ __... _ ..- ._- - - l0 15 20 25 30 7905412-8 The neutral position is shown in Figure 8, a from the side and b above from. Figure 8c shows the position after a displacement.

Feed offset From the neutral position, the teeth of one tooth group are displaced in the forward or backward direction of the saw object in relation to the teeth of the other group. This med- for one or the other tooth group to take over a larger part of the cutting work.

This feed offset can uniformly cover the whole the saw cut - as shown in Figure 8 d - or can the displacement be uniform so that one tooth group in a part of the saw cut from the neutral position is shifted forward more and more in relation to second group teeth.

This position is shown in Figure 8 e, Figure 8 f shows a position where the teeth are both displacement-shifted and non-uniform feeding shifted.

From an intermediate position in the saw cut, you then get in one direction a perpendicular action increasing with the distance from the intermediate position the sawing direction while in the opposite direction in the saw cut get straight opposite effect. This setting was used to solve the problems when the texture of the saw object in different parts of the cut cause different sizes forces or forces in different directions. Such an attitude at texture free material gives a saw surface in the form of a rotating plane.

A forward and backward displacement of the group's teeth can be achieved in circular sawing by a displacement of the shaft center of the teeth of either group. Is this shift made in mainly along the sawing direction, the entire sawing direction is affected one way or the other. If the displacement is made across the sawing direction you get the just outlined position where one group's teeth from one intermediate position in a part of the saw cut seems in one direction, but they acts in the other direction in the opposite part of the saw cut.

Through such changes, the impact of the workpiece can varying texture and hardness are counteracted and kept under control. 10 15 20 25 30 7905412-8 Compensation can also be given against oblique sawing caused by uneven worn saw teeth, tooth front deformities, etc. This means a significantly increased lateral stability. You can use lower input voltage forces and especially thinner blades. The result is even and stable saw cuts and an increased saw yield. These are discussed below questions in more detail.

As another prerequisite for the invention, it applies that use mirror-inverted tooth shapes. The teeth in one group should when sawing textureless material, have one facing it second group opposite and clearly marked lateral force. Both the lateral forces of the groups shall be of the same order of magnitude. One the lateral force of the group is thus directed towards the other group, which means that the groups are automatically merged and form an end system.

The teeth should be so designed that they squeeze both saw blades against each other. This can be done in two basically different ways.

On the one hand, the teeth can be angled so that the feeding force compresses saw blades. This is shown in Figure 2. According to the second and more efficient In this way, the teeth are designed so that the cutting force is compressed saw blades. This is shown in Figure 8. Both methods can of course be used at the same time. Especially in figure 2 but also in figure 8 has the tooth fronts angled hard. This has been done only to clearly show the design tion.

The invention will be described below with application to circular saws, but it can also be used with suitable modifications on other saw shapes such as band, frame or jigsaws.

Figures 1 and 2 give an example of the two defined above the dental groups. Here are two similar inverted circular saw blades.

They have the same thickness, diameter and number of teeth N, ie with one tooth pitch A in degrees = 360 / N. Figure 1 shows one blade solid and the other dashed with neutral division offset B = A / 2. Figure 2 shows half the cross-sections of the two blades and with one of many conceivable possibilities for asymmetric, shaped and mirror-inverted tooth front design, denoted by R respectively L. Separated rotations of the blades take place by means of l0 15 20 25 30 35 7905412-8 circularly arranged and described in more detail in Figures 5, 6 and 7 the pins.

An arbitrary number of these guide pins are adapted with slight clearance to the circular recesses of the associated blade, 3 in figure 1, as well as provide sufficient leeway in the circular, larger and in neutral position center coinciding recesses, 4, in the other in otherwise uniform fixed inverted blade. The control of the two systems sticks with relative relative freedom of rotation with respect to the blade center can affect the tooth division situation B so that B can become greater or less than A / 2. When, for example, B is greater A / 2 comes an L-tooth to approach the tooth edge side of an R-tooth. The L-tooth takes over a larger part of the cutting work with a corresponding reduction in the work of the R-tooth, whereby the lateral force of the L-tooth increases while The R-tooth decreases. For each pair of R- and L-teeth becomes thereby a net lateral force directed towards the blade with R-teeth. In the case of texture free saw material, this means a hook sawing to the right seen in feed direction or in the case of obliquely textured saw material with left- compressive tooth forces that these forces with adapted tooth pitch situation B can be balanced with straight sawing as a result. For- the holding becomes inversely in the tooth division situation B less than A / 2.

The design of the drive device and the B-control for the combination of the two equal but inverted blades is shown in figure 7.

The drive hub consists primarily of an outer, 5, and an inner, 6, hub cylinder. Both are mutually linked to the holder the flanges, 7 and 10, for the guide pins 14 and 15, respectively Figure 5 shows the holding flanges, 7, for the outer hub cylinder 5 designed with large and free holes for the guide pins, 15 in Figure 7, which is coupled to the inner hub cylinder 6.

The middle portions of the two hub cylinders are provided with longitudinal continuous and continuous slots, 8 and 9 in Figure 7, in which one continuous guide pin, 13, can be displaced in the axial joint of the hub and then via a center shaft connected to it, 12. One of the pairs slots, 8 or 9, in the outer or inner hub cylinder are formed with a slight screw shape with such a pitch that at axial and maximum displacement of the central control shaft, 12, a relative rotation between the two hub cylinders of slightly less than A degrees are obtained. lO l5 20 25 30 35 7905412-8 Of the outer ends of the hub, ll in figure 7, which are fixedly connected to the inner hub cylinder, 6, at least one must be drilled for review of the control shaft, 12. The other can be directly connected to drive device, for example an engine as shown in Figure 4.

In the assembly drawings, Figure 3 and Figure 4, have crosses specified locations of sensing means for the saw blades side deviations. Since the design of these bodies as well as the coupling units with known PID controls for appropriate control of the the shaft, 12 in Figure 4, in principle does not affect the invention these are not further specified. However, the following options may be a simple method with advantages also from a cooling point of view.

At the measuring points are placed appropriately designed and adjacent water nozzles. They are fed from ordinary water supply via only throttle valves. These nozzles are connected to both sides of a piston system, which is directly coupled to the control shaft, 12 in figure 7.

Simplified, the control shaft itself can be terminated with a piston in the system in question according to the right part of Figure 7.

Apart from the case of the steering shaft, 12 in Figure 7, directly forced control for manual or programmed hook sawing can also such sawing is performed by supplying the sensing means a controlled lateral movement. This is made possible by making the saw blades axially easily displaceable on the hub guide pins.

A central feature of the invention is that of the saw means - ie on paired R and L teeth - only two forces will act, the tangential acting shear force as well as the feed force. With in other words, the lateral forces on the saw member have been eliminated. From this There is also the risk of critical deflection through the feed force impact has been significantly reduced or expressed differently in the past affected cracking effect becomes negligible. The bending force of the feed force torque becomes practical through adequate regulation of the saw blade taken eliminated. With a suitable chip angle and tooth sharpness can also the feed force is kept at an insignificant value. Total possible makes this concentrated use of power for cutting work an essential reduction of the blade thickness and thus the groove width and the loss. Easily bendable blades can for hook sawing application compliantly adhere to a sharp bend. lO 15 7905412-8 In the embodiments straight saws, for example belt and frame-saws, the two tooth displacement methods, division and feeding is also combined. This then gives the opportunity to via two sensing means, located on either side of the workpiece, through perform sawing along a screw plane if the workpiece can be rotated or compensated for a texture varying along the saw cut.

This description is intended to clarify the principles of the invention and to give examples of how they can be designed in more detail.

Variants other than those concerned here can be designed. As examples of such various designs of the tooth tips can be mentioned, they can also bond with the blade / blade in different ways, the teeth as a whole can further designed as knives or cutters etc. Also the blade / blade can be varied. By the saw through the adjustable action of the teeth himself seeks his definite path through the wood, the blade is exposed as previously stated only for low stress, these bodies can therefore be made very thin, possibly replaced with spokes, etc.

In the case of manual or automatic control devices many variants can be developed with known control and regulation technology.

Of course, such variants are included in the invention.

Claims (4)

10 l5 20 7905412-8 PATENT REQUIREMENTS l. Drawn with similar tooth pitch, each tooth ntrormed with mirror- Device for controlled and controlled sawing, can - of two saw blades (eg saw blades, 1 and 2) symmetrical and skewed tooth fronts (R and L ) and with an edge direction which forms an angle with the cutting direction of the teeth or with a direction perpendicular to the cutting direction or with both these directions and that the saw blades and teeth are designed so that the blades are compressed when sawing and further that the two saw blades - and thus the teeth - are via control device mutually displaceable during sawing. 2. A feature according to claim 1, Device according to claim 1, that the displacement between the teeth of the two saw blades or saw blades (Figs. 1 and 2, R and L) takes place along the connecting line between the teeth (Figs. 8, 8b and 8c) or in the sawing direction (8d and 8e) or in both of these directions (8f). 3. know or just outside the saw zone and that the control means are actuable. Device according to claims 1 and 2, a, that position sensing means are arranged in via adapted signal processing from these. 4. A device according to claim 1-3, that the position sensing means as well as the sawing means are easily movable across the saw plane.