EP1671732A1 - Saw blade and hand saw - Google Patents

Abstract

The saw blade has a series of teeth at a longitudinal edge, wrenched in alternate directions and formed in KV shape which is defined by a first flank angle alpha, a second flank angle Beta, and a rake angle gamma. The first flank angle lies between about 50.0deg to 54.0deg. The second flank angle lies between about 14.0deg to 16.0deg. The rake angle lies between about 11.2deg to 14.0deg. The first flank angle lies between about 53.0deg to 54.0deg, the second flank angle lies between about 14.0deg to 15.0deg, and the rake angle lies between about 13.0deg to 14.0deg. The tooth series has a tooth pitch between 2 to 4 teeth per inch (25.4 mm), such as about 2.3 to 3.4 teeth per inch, preferably about 3.2 or 2.5 teeth per inch.

Description

The invention relates to a saw blade for a hand saw with a trained on the longitudinal side row of set teeth.

There are a variety of tooth shapes that are used for manually operated saws or motorized saws with alternately reciprocating saw blade. Probably the most commonly found tooth forms of longitudinal saw blades are among others: the AV tooth shape, the KV tooth shape, the M tooth shape, the NU tooth shape, the NV tooth shape, the PV tooth shape, which tooth shape types, for example, in the Lueger Lexicon of Technology , Rowohlt, vol. 2, 1975, page 436.

Schemes of the tooth forms of saw blades known per se are shown in the appended FIG. The AV tooth is defined by a symmetrical triangular tooth. The KV tooth is defined by an unbalanced open-space tooth body, the tooth body extending from a reinforced broad tooth base along a second flank which forms a so-called second flank angle with respect to a saw blade normal. In the area of the tooth tip, a second, flatter edge, which defines a first flank angle relative to the saw blade normal, adjoins the second tooth flank. From the tip of the tooth body extends at the first and second edge opposite chip edge in a rake angle relative to the saw blade normal continuously linearly to the tooth base. The so-called M-tooth has the shape of an M, which is formed at the top of a small central groove. The M-tooth is designed with equilateral parallel cutting edges. The NU tooth shape is determined by an asymmetrical triangular tooth shape with a flat extended tooth gap between each two adjacent teeth. The NV tooth shape has the same shape as the NU tooth shape, but lacks the extended tooth gap between two teeth. The PV tooth shape is also defined by an asymmetrical triangular tooth, but with a curved free surface and a strongly rounded tooth gap bottom.

In order to avoid sagging of the saw on the material to be cut, the saw teeth are usually limited in all tooth shape types, d. H. alternately bent to the right or left.

It is an object of the invention to develop a saw blade, in particular for a hand saw for separating pulp materials, such as wood, which increases the sawing efficiency while maintaining sawing work and / or reduces the sawing force to be applied for a predetermined amount of sawed blade can.

This object is solved by the features of claim 1. Thereafter, saw blade is provided with a formed on a longitudinal side row of set teeth in a KV tooth shape, which is defined by a first flank angle, a second flank angle and a rake angle, wherein the first flank angle between about 50.0 ° to 54.0 ° , the second flank angle between about 14.0 ° to 16.0 ° and the rake angle between about 11.2 ° to 14.0 °

After a variety of comparative experiments, it has been found that the most favorable tooth shape for processing wood materials, such as beech, pine, pine, medium-density fiber pieces (MDF boards) and the like with a saw blade processed both in a hand saw and in a sawing machine with a saw blade can be, which has a row of teeth in KV tooth shape. Surprisingly, the experiments also showed that even changes in the angular sizes in a range of several 10 minutes, in particular half degrees, significant improvements but also resulted in deterioration of the sawing performance. By means of a complex series of experiments whose sequence and evaluation will be described later, it was unexpectedly shown that both the sawing efficiency and the sawing force are optimized in the combined angular range limits according to the invention.

In a first preferred embodiment of the invention, the best sawing results were achieved when an angle combination of about 53 ° to 54 °, preferably about 53.6 °, for the first flank angle, about 14 ° to 15 °, preferably about 14.6 ° was set for the second flank angle and about 13 ° to 14 °, preferably about 13.3 ° for the rake angle.

In a second alternative preferred saw blade design turned out to be particularly favorable when the first flank angle between about 50.0 ° and 51.0 °, preferably at about 50.7 °, the second flank angle between about 15.0 ° and 16.0 °, preferably at about 15.7 ° and the rake angle between about 12.0 ° and 13.0 °, in particular at 12.8 °, combined in a saw blade.

In a third, preferred alternative, the best test results were found when for the first flank angle about 53.0 ° to 54.0 °, preferably about 53.2 °, for the second flank angle about 13.5 ° to 14, 5 °, preferably about 14.0 ° and for the rake angle about 11.2 ° to 12.0 °, preferably about 11.8 ° is selected.

Particularly surprisingly, it has been found that the above dimensions for the first flank angle, the second Flarikenwinkel and the rake angle of a KV tooth shape has always provided excellent cutting results regardless of the length dimensioning of the tooth itself and the zusausgenden wood material. For example, it has been found that for the three alternatives mentioned above, the best sawing results are achieved when the pitch of the respective row of teeth in a range between two to four teeth per inch (25.4 mm), in particular between about 2.3 to 3.4 Teeth per inch, preferably about 3.2 or 2.5 teeth per inch, is determined.

Particularly at the first preferred angular combination of first flank angle, second flank angle and rake angle, an optimum tooth spacing value of about 3.2 teeth per inch was surprisingly found, at which the best sawing results were achieved and which value is also relevant to the third preferred angle combination.

For the second preferred choice of the angle combination, the value 2.5 turned out for an optimum tooth pitch.

To test this optimized sawing performance of saw blades, the inventor carried out experiments in which a wide variety of flank and rake angle combinations were used for use on several similar Fasersägegütern under constant environmental conditions. A first series of experiments was carried out on a 34 x 30 mm piece of book. In a second experimental range sawing processes were initiated on a jaw piece of a 74 x 34 mm cross-section. For a third representative series of tests saw blades with varying flank and rake angle combinations were used on a medium density fiberboard with a cross section of 74 x 30 mm.

For the experimental setup, the respective saw was clamped in a dynamometer to determine which sawing force is applied to each saw type in the direction of advance of the saw blade and in the vertical transverse direction. In addition, a meter was assigned to the workpiece, which meter determines the amount of stress on the weight of the shaved by the saw blade shavings or by the removed from the sawing material volume. It is clear that essentially the same tool material, in particular the same tool steel, having substantially identical surface finish was used for each of the saw blades to be tested.

• Schneidkraft F, die durch den Dynamometer gemessen ist;
• Länge L des Sägenhubs, welche im wesentlichen aufgrund identischer Sägeblattaußenformen im wesentlichen für jeden Sägetyp gleich groß ist;
• Anzahl N von Sägehuben zum Durchsägen des Sägeguts;
• Querschnittsfläche A in Schnittebene des Sägeguts; und
• die Breite B der Schnittfuge;

und durch die Gleichung $$\mathrm{S}\mathrm{C}\mathrm{E}=\left(\mathrm{F}\mathrm{L}\mathrm{N}\right)/\mathrm{A}\mathrm{B}$$

errechnet.To determine a value for the sawing effectiveness, a test variable SCE is defined, which allows statements about the sawing efficiency of the respective saw blade type. The test size SCE is determined by the following parameters

• Cutting force F measured by the dynamometer;
• Length L of the saw stroke, which is substantially the same size due to identical saw blade outer shapes substantially for each type of saw;
• Number N of sowing tubes for sawing through the sawed material;
• Cross-sectional area A in sectional plane of the sawing material; and
• the width B of the kerf;

and by the equation $$\mathrm{S}\mathrm{C}\mathrm{e}=\left(\mathrm{F}\mathrm{L}\mathrm{N}\right)/\mathrm{A}\mathrm{B}$$

calculated.

It has been found that even changing one of the three shape-determining KV tooth form angles above in ranges of less than 0.5 ° has a significant influence on SCE value.

In a first trial, a known saw blade sold under the brand name Sharptooth 15-334 by the company with the company component, Stanley Works, and a rake angle of approximately 18.0 °, a first flank angle of approximately 63.0 ° and a second flank angle of about 11.0 °, with the third embodiment of the saw blade according to the invention - first flank angle at about 53.0 ° to 54.0 °, preferably about 53.2 °, second flank angle at about 13 , 5 ° to 14.5 °, preferably about 14.0 ° and the rake angle at about 11.2 ° to 12.0 °, preferably about 11.8 ° - compared. Both saws had approximately the same tooth pitch. With the saw blade according to the invention an increase in sawing efficiency (SCE) over the known saw blade of over 26% and an increase in the chip quantity of over 43% was achieved in the piece of pine, although the applied sawing force was only increased in the saw blade according to the invention by up to 13% , In the case of the beech, the SCE improvement was over 43% and the amount of stress was over 41%, although the saw force was only increased by up to 1%. The MDF piece achieved an SCE improvement of over 22% and an increase in the amount of stress of over 17%, although the sawing force to be applied was only increased by up to 3%.

In a second test run, the saw blade sold under the brand name Sharptooth 20-065 by the above mentioned company Stanley Works and has a rake angle of 15.0 °, a first flank angle of approx. 56.0 ° and a second flank angle of approx 17.0 °, with the second embodiment according to the invention - first flank angle between about 50.0 ° to 51.0 °, in particular about 50.7 °, second flank angle at about 15.0 ° to 16.0 ° , In particular about 15.7 ° and the rake angle at about 12.0 ° to 13.0 °, especially at 12.8 °, compared. Both saws showed approximately the same tooth pitch. With the saw blade according to the invention an increase in sawing efficiency (SCE) over the above-mentioned known saw blade of over 27% and an increase in the chip quantity of more than 56% was achieved in the jaw piece, although the applied sawing force in the saw blade according to the invention by only up to 7% was increased. In the case of the piece of beech, the SCE improvement was over 27% and the tension increased by more than 36%, although the sawing force to be applied was also increased by only 1%.

In a third trial, a known saw blade sold under the trade name ProCut by the company with the company component Bahco and a rake angle of about 12.0 °, a first flank angle of about 52.0 ° and a second Flank angle of about 24.0 °, with the third embodiment of the saw blade according to the invention - first flank angle at about 53.0 ° to 54.0 °, preferably about 53.2 °, second flank angle at about 13.5 ° to 14.5 °, preferably about 14.0 ° and the rake angle at about 11.2 ° to 12.0 °, preferably about 11.8 ° - compared. Both saws showed approximately the same tooth pitch. With the saw blade according to the invention, an increase in sawing efficiency (SCE) over the known saw blade ProCut of over 54% and an increase in the chip quantity of more than 53% were achieved in the jaw piece, although the sawing force to be applied only increased by up to 7% in the saw blade according to the invention has been.

In a fourth test run, a known saw blade sold under the trademark "Superior Laminator" by the company having the company component Bahco and a rake angle of about 15.0 °, a first flank angle of about 54.0 ° and a second Flank angle of about 26.0 °, with the second embodiment of the saw blade according to the invention - first flank angle at about 50.0 ° to 51.0 °, preferably at about 50.7 °, the second flank angle at about 15, 0 ° to 16.0 °, preferably at about 15.7 °, and the rake angle at about 12.0 ° to 13.0 °, especially at about 12.8 ° - compared. Both saws had approximately the same tooth pitch. With the saw blade according to the invention, an increase in the sawing efficiency (SCE) over the known saw blade of more than 11% and an increase in the chip quantity of more than 12% was achieved in the book piece, although the applied sawing force was only increased by up to 1%.

It should be noted that the desired degrees of angularity, except for the first decimal place, are readily determinable with known precision measuring techniques, such as laser technology, the touch probe method, the so-called co-ordinate measuring method, etc. Reference should also be made to the measurement methods in the so-called reverse engineering (replica) technique with 3-dimensional scanning technology and subsequent CNC production, for example by milling or grinding. Reference is made expressly to the measuring devices of the Mitutoyo company, in particular the Series 525 SVC-3000 H4 formtracer, and the Renishaw company, in particular the CMM products.

The invention also relates to a hand saw with a saw blade according to the invention.

Further features, properties and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the accompanying drawings, in 2 of a section A of a saw blade according to the invention with a limited KV tooth shape is shown, which is also called Hannibal toothing.

The saw blade 1 according to the invention comprises a series of set teeth 3 in a KV tooth form, which is defined by a first flank angle α, a second flank angle β and a rake angle γ. The first flank angle α is given by the circumferential area between a first flank 5 of the tooth 3 and the saw blade normal N, the second flank angle β by the peripheral area between the second flank 7 of the tooth 3 and the saw blade normal N and the rake angle γ by the peripheral area between the Chuck edge 9 of the tooth 3 and the saw blade normal N.

In a first alternative embodiment, a value of 13.3 ° is provided for the rake angle γ, a value of 53.6 ° for the first flank angle α, and a value of 14.6 ° for the second flank angle β.

In a second alternative embodiment according to the invention, the KV tooth shape is the rake angle γ at 12.8 °, the first flank angle α at 50.7 ° and the second flank angle β at 15.7 °. In this design, the pitch is set at 2.54 teeth per inch.

In a third preferred embodiment of the invention, the rake angle γ is set at 11.8 °, the first flank angle α at 53.2 ° and the second flank angle β at 14 °. Here, a tooth pitch of 3.2 inches is set.

The features disclosed in the foregoing description, the figures and the claims may be of importance both individually and in any combination for the realization of the invention in the various embodiments.

Claims (6)

Saw blade for a hand saw with a formed on a longitudinal side row of set teeth (3) in a KV tooth shape, which is defined by a first flank angle α, a second flank angle β and a rake angle γ, characterized Porsche Style , that the first flank angle α is between approximately 50.0 ° to 54.0 °, - The second flank angle β is between about 14.0 ° to 16.0 ° and - The rake angle γ is between about 11.2 ° to 14.0 °. Saw blade according to claim 1, characterized in that the first flank angle α is between approximately 53.0 ° and 54.0 °, in particular approximately 53.6 °, - The second flank angle β between about 14.0 ° to 15.0 °, in particular at about 14.6 °, and - The rake angle γ between about 13.0 ° to 14.0 °, in particular at about 13.3 °. Saw blade according to claim 1, characterized in that the first flank angle α is between approximately 50.0 ° and 51.0 °, in particular approximately 50.7 °, - The second flank angle β between about 15.0 ° to 16.0 °, in particular at about 15.7 °, and - The rake angle γ between about 12.0 ° to 13.0 °, in particular at about 12.8 °, is located. Saw blade according to claim 1, characterized in that the first flank angle α is between approximately 53.0 ° and 54.0 °, in particular approximately 53.2 °, - The second flank angle β between about 13.5 ° to 14.5 °, in particular at about 14.0 °, and - The rake angle γ between about 11.2 ° to 12.0 °, in particular at about 11.8 °, is located. Saw blade according to one of Claims 1 to 4, characterized in that the row of teeth has a pitch of between 2 to 4 teeth per inch (25.4 mm), in particular approximately 2.3 to 3.4 teeth per inch, preferably approximately 3.2 or 2.5 teeth per inch. Handsaw with a trained according to one of claims 1 to 5 saw blade (1).

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