Saw blade

Abstract

A saw blade for an electric saw tool with a drive shaft making a reciprocating arcuate swing motion, the saw blade comprising a saw plate which has centrally a coupling part for connecting and fixing the saw plate to the drive shaft of the saw tool and has an appearance as being elliptic, and has cutting teeth on the outer periphery. Also, a saw blade for an electric saw tool with a drive shaft making a reciprocating arcuate swing motion, the saw blade having at one end a coupling part for connecting and fixing the saw blade to the drive shaft of the saw tool and having at the other end cutting teeth of the saw blade, and height of the cutting teeth being smaller in the order from near to at both ends of a line of the teeth.

Claims

1. A saw blade for an electric saw tool with a drive shaft making a reciprocating arcuate swing motion, the saw blade having at one end a coupling part for connecting and fixing the saw blade to the drive shaft of the saw tool and having at the other end cutting teeth of the saw blade, the cutting teeth each having a tooth base and an opposing tooth tip, the bases being arranged in a straight line, the cutting teeth having in sequence a first end, a central region and a second end and characterized in that the tips of the cutting teeth of the first end and the tips of the cutting teeth of second end extend to a height smaller than the height to which the tips of the cutting teeth of the central region extend.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic plan view showing an example of a saw blade according to the present invention.

(2) FIG. 2 is a schematic perspective view showing an example of a saw blade according to the present invention.

(3) FIG. 3 is an explanatory plan view showing comparison between a conventional saw blade (FIG. 3(a)) and an example of a saw blade according to the present invention (FIG. 3(b)).

(4) FIG. 4 is an explanatory view showing another example of a saw blade according to the present invention, FIG. 4(a) being a schematic plan view and FIG. 4(b) a schematic side view.

(5) FIG. 5 is an enlarged view of the parts A, B, and C shown in FIG. 4(a).

(6) FIG. 6 is a plan view showing an electric saw tool to which the saw blade according to the present invention is mounted, and an exemplified conventional art of saw blade conventionally mounted to the electric saw tool.

PREFERRED EMBODIMENTS OF THE INVENTION

Example 1

(7) FIGS. 1 and 2 show an example of a saw blade 1 according to the present invention (called hereunder the saw blade 1), FIG. 1 being a plan view and FIG. 2 a perspective view. As seen from the drawings, the saw blade 1 in this example is generally elliptic in shape.

(8) The saw blade 1 is a saw blade to be mounted to a tool having a drive shaft of a quality to make an arcuate swing (for example, the tool shown in FIG. 6). The central angle of the arcuate swing in this example is 1.6 degree.

(9) Cutting teeth 11 are formed on the whole of the elliptic periphery of the saw blade. Teeth 11 are each symmetrically formed at the left and right sides with respect to a line connecting the center of the arcuate swing with crests of the teeth. Thus, there is not caused any difference of the cutting capability in the reciprocation upon the arcuate swing. The number of the cutting teeth 11 is about 250 in this example which is more than twice in comparison with the number of cutting teeth on round saw blade of the conventional hand-held type saw.

(10) In the present invention, the cutting teeth perform the arcuate swing as mentioned previously. Distances (of separation, more precisely, angles of separation) between the cutting teeth neighboring with each other, are restricted by the arcuate swing angle. In other words, a cutting tooth reciprocates in a given angle and another cutting tooth neighboring that cutting tooth does similarly reciprocate in the same angle. If the cutting teeth are separated from each other by more than that angle of reciprocation, there is created a part which is not subjected to cutting.

(11) Namely, it is preferable that the total number of the cutting teeth is more than 225 (=3601.6, when the arcuate swing is performed with an angle of 1.6 degrees), and more than 180 (=3602, when the arcuate swing with 2 degrees).

(12) The angle for the arcuate swing in the range of 1 through 3 degrees may be best, while it is likely to injure workers and has a problem of safety when the arcuate swing angle is over that range, and the capability of cutting is deteriorated when the arcuate swing angle is below that range and thereat too many total number of cutting teeth work together.

(13) A coupling part 2 to connect the saw blade 1 with the tool body is positioned at the center of the saw blade 1 according to the present invention. The coupling part 2 in this example is so structured that the coupling part 2 can be attached and fixed to the tool body with the attaching angle being changeable by pitch of 45 degrees. Besides, in this example, the saw blade 1 is attached to the tool in such manner that the saw blade 1 is, for having no projected part on the rear surface (the surface facing the wood upon cutting operation), provided with a swollen part at the side of mounting the saw blade to the tool, a drive shaft for motor in the saw tool is inserted into a mounting opening 21 formed on the swollen part's upper surface and the motor's drive shaft projecting downwards from the opening 21 is fixedly screwed by use of a coupling screw member (not shown). In other words, the coupling screw member is screwed at the rear side of the saw blade. In the shown example, the coupling screw member is placed in the inner space of the swollen part. By this, workability is improved and use is widened.

(14) FIGS. 3(a) and 3(b) are schematic plan views showing and comparing a conventional type of saw blade B with a saw blade 1 according to the present invention, both used in this kind of sawing tool.

(15) FIGS. 3(a) and 3(b) also show the state of cutting operation that the tool body is pushed in the direction of the arrow into the comparatively thick wood W to be worked and cutting progresses to some extent.

(16) For comparison, features of the cutting teeth p, q, r in FIG. 3(a) and P, Q, R in FIG. 3(b) are noted.

(17) The cutting teeth p, r, P, R are positioned at the outer end parts of the saw blades B and l and there contribute to cutting. And the cutting teeth q, Q are positioned almost centrally between the outer end parts.

(18) When the saw blade performs the arcuate swing, all of the cutting teeth naturally also perform the arcuate swing. In the conventional saw blade B shown in FIG. 3(a), a cutting tooth extending in the radial direction from the center O of the arcuate swing is only the cutting tooth q. Other teeth than the cutting tooth q positioned outwardly thereof gradually deviate from the radiuses from the center O, and cutting teeth p, r substantially deviate from the radiuses which direction no longer called radiuses. Furthermore, there exist no cutting teeth outwardly of the cutting teeth p, r, whereby the saw blade B when swings merely collide against the wall C.

(19) Moreover, in FIG. 3(a), amid the cutting operation, the tool substantially cannot be changed of the direction of being pushed into the wood from the initial direction shown by the arrow to any directions. Unless the tool is continued to be pushed precisely in the direction shown by the arrow, the frequency and force of collision increase to thereby make higher the previously mentioned danger of smoking from heating and deformation of saw blade.

(20) Contrary to the above, the saw blade 1 according to the present invention, namely, the feature shown in FIG. 3(b), cuts the wood and forms a hole in shape of an arc of an ellipse. All the cutting teeth on the saw blade are arranged in the radial direction from the center O. In detail, the cutting teeth P, Q, R are arranged in a manner and situation of being capable of performing cutting. When the tool body is pushed into the wood in the direction shown by the arrow, mainly the cutting tooth Q and several cutting teeth at both sides of the cutting tooth Q contribute to the cutting. And when the tool body is pushed in the direction of the cutting tooth P, the wood is cut in this direction.

Example 2

(21) FIG. 4 is an explanatory view showing another example of a saw blade 10 according to the present invention (called hereunder the saw blade 1), FIG. 4(a) being a schematic plan view and FIG. 4(b) a schematic side view. A saw blade 10 is a saw blade to be mounted to a tool having a drive shaft of a quality to make an arcuate swing (for example, the tool shown in FIG. 6). The saw blade 10 is connected and fixed, at its coupling part 20 to the drive shaft of the tool. Besides, the saw blade 10 is provided with cutting teeth 110 at a remote end opposite to the coupling part 20.

(22) In this example, the central angle of the arcuate swing is 1.6 degrees.

(23) The cutting teeth 110 are arranged in a line but are not uniform in height with teeth near and at both ends of the saw blade being smaller in height. FIG. 5 is an enlarged view of the parts C, D, E shown in FIG. 4(a), showing the cutting teeth 110 around the central region (part D) of the saw blade 10, around the right end (part E), and around the left end (part C).

(24) As seen in the drawings, the cutting teeth near and at both ends of the saw blade 10 are made slightly smaller in height. Thus, appearance of these teeth is not largely different from the conventional saw blade (for example, that shown in FIG. 6). However, the slight difference of height among the cutting teeth at the saw blade's both ends provides a quite large effect in and upon cutting.

(25) The inventor made a trial manufacture and experiment and found that the saw blade 10 according to the present invention can cut, with having energy left, a thick wood which it is hard or impossible for a conventional saw blade to cut and form a through bore.