Handsaw

Abstract

A handsaw with which chip clogging is eliminated significantly, the pitch of the tooth points kept fine rather than coarse, a large area secured for the cut end face, degradation in cutting caused by the chip clogging prevented sufficiently. The handsaw has a plurality of saw teeth arranged on a longitudinal edge (21) of the saw blade (20). The saw teeth are formed as prism-shaped teeth (30) each having a shape of a prism, which are configured such that at least adjacent prism-shaped teeth (30) rise at a same rising angle from the edge surface (21a) of the longitudinal edge (21) of the saw blade (20), to cause the space (S) between the adjacent prism-shaped teeth to be constant in the rising direction.

Claims

1. A handsaw having a plurality of saw teeth arranged on a longitudinal edge of a saw blade, the saw teeth being configured as prism-shaped teeth each having a shape of a prism, the prism-shaped teeth being configured such that at least adjacent prism-shaped teeth rise at a same rising angle from an edge surface of the longitudinal edge of the saw blade, to cause spaces between the adjacent prism-shaped teeth to be constant in a rising direction in which the prism-shaped teeth rise; wherein the prism-shaped teeth are triangular prism-shaped teeth that extend from the longitudinal edge of the saw blade, each of said prism-shaped teeth having an obliquely cut end face, three parallel lateral edges, and three intersecting lateral faces, each of the lateral faces bordered by two of the three parallel lateral edges, and said prism-shaped teeth being separated from each other by respective planar surfaces of the longitudinal edge of the saw blade, the three parallel lateral edges of each triangular prism-shaped tooth including two lateral edges configured as lateral edges of a flush lateral face of the three intersecting lateral faces, the flush lateral face rises flush with one of front and back surfaces of the saw blade, and a remaining lateral edge of the three parallel lateral edges has said spaces on both sides and is configured as a lateral edge that is parallel to the two lateral edges of the flush lateral face and that rises flush with the other of the front and back surfaces of the saw blade; the triangular prism-shaped teeth are arranged in alternating orientations one after another such that the flush lateral faces of the respective teeth are located alternately on the front and back surfaces of the saw blade; each triangular prism-shaped tooth has the obliquely cut end face at a tip end of the tooth obtained by obliquely truncating the triangular prism-shaped tooth, the obliquely cut end face having an oblique triangle that spans an entire thickness of the saw blade between the front and back surfaces; among the three parallel lateral edges of each triangular prism-shaped tooth, each of both lateral edges belonging to the flush lateral face has a vertical cutting edge formed thereon; and among edges belonging to the obliquely cut end face of each triangular prism-shaped tooth, each of the edges not belonging to the flush lateral face has a horizontal cutting edge formed thereon.

2. The handsaw according to claim 1, wherein the same rising angle of each of the adjacent prism-shaped teeth has a tolerance of 5 degrees, and each of the spaces between the adjacent prism-shaped teeth being constant in the rising direction includes any space with an increase within 10 degrees in angle or a reduction within 10 degrees in angle.

3. The handsaw according to claim 1, wherein the lateral edges of each lateral face of each prism-shaped tooth are configured to rise parallel to each other or at a crossing angle of within 5 degrees from the parallel.

4. The handsaw according to claim 1, wherein the triangular prism-shaped teeth are isosceles triangular prism-shaped teeth.

5. The handsaw according to claim 4, wherein the same rising angle of each of the adjacent prism-shaped teeth has a tolerance of 5 degrees, and each of the spaces between the adjacent prism-shaped teeth being constant in the rising direction includes any space with an increase within 10 degrees in angle or a reduction within 10 degrees in angle.

6. The handsaw according to claim 4, wherein the lateral edges of each lateral face of each triangular prism-shaped tooth are configured to rise parallel to each other or at a crossing angle of within 5 degrees from the parallel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a front view of a handsaw according to a first embodiment of the present invention.

(2) FIG. 2 shows details of the handsaw according to the first embodiment of the present invention, where (A) is a plan view and (B) is a front view.

(3) FIG. 3 is a perspective view showing details of the handsaw according to the first embodiment of the present invention.

(4) FIG. 4 shows saw teeth of the handsaw according to the first embodiment of the present invention, where (A) is a plan view and (B) is a perspective view observed from the front side.

(5) FIG. 5 shows dimensional relationships of respective parts of the saw tooth of the handsaw according to the first embodiment of the present invention.

(6) FIG. 6 shows details of a handsaw according to a second embodiment of the present invention, where (A) is a plan view and (B) is a front view.

(7) FIG. 7 shows details of a handsaw according to a third embodiment of the present invention, where (A) is a plan view and (B) is a front view.

(8) FIG. 8 shows details of a handsaw according to a fourth embodiment of the present invention, where (A) is a plan view of triangular prism-shaped teeth and (B) is a plan view of trapezoidal prism-shaped teeth.

(9) FIG. 9 shows details of a handsaw according to a fifth embodiment of the present invention, where (A) is a plan view of triangular prism-shaped teeth and (B) is a plan view of trapezoidal prism-shaped teeth.

(10) FIG. 10 shows an example of a conventional ripsaw, where (A) is a plan view and (B) is a perspective view observed from the front side.

(11) FIG. 11 shows an example of a conventional crosscut saw, where (A) is a plan view and (B) is a front view.

(12) FIG. 12 shows an example of a conventional handsaw.

MODES FOR CARRYING OUT THE INVENTION

(13) Handsaws according to embodiments of the present invention will be described with reference to the drawings below.

(14) First, a first embodiment will be described with reference to FIGS. 1 to 5.

(15) Referring to FIG. 1, a handsaw has a grip 10, a saw blade 20, and saw teeth 30. The grip 10 is only partly shown in the figure.

(16) While the handsaw shown is a folding handsaw with the saw blade 20 foldable into the grip 10, the handsaw does not necessarily have to be of the folding type; any types of handsaws can be adapted.

(17) The handsaw is a so-called single-edged saw, having the saw teeth 30 arranged on one longitudinal edge 21 of the saw blade 20. Alternatively, it may of course be a double-edged saw with saw teeth 30 arranged on both longitudinal edges 21 of the saw blade 20.

(18) Further, while the handsaw shown in FIG. 1 is a pull-type saw, it may be a push-type saw.

(19) Referring to FIGS. 2 to 5 as well, the saw teeth are configured as prism-shaped teeth 30 in the first embodiment.

(20) The prism-shaped teeth 30 are configured to rise from an edge surface 21a of a longitudinal edge 21 of the saw blade 20.

(21) For the prism-shaped teeth 30, rising angles are set to be constant such that they rise in a same direction from the edge surface 21a. In the first embodiment, the rising angle of each prism-shaped tooth 30 is set to be a right angle of 90 degrees. The rising angle of each prism-shaped tooth is not limited to the right angle; the teeth may be slanted as long as their angles are constant.

(22) With the rising angle constant for each prism-shaped tooth 30, a space S between each pair of adjacent prism-shaped teeth 30 becomes constant in the rising direction of the prism-shaped teeth. This eliminates the conventional problematic structure in which the space between the teeth becomes narrower from the tip ends toward the bases of the teeth. It is thus possible to fully solve the conventional disadvantage that the cutting performance deteriorates with the tapered spaces between the teeth clogged with chips.

(23) Incidentally, in order to make the space S between the adjacent prism-shaped teeth 30 constant in the rising direction of the prism-shaped teeth, it is only necessary that at least adjacent prism-shaped teeth 30, 30 rise at a same rising angle from the edge surface 21a of the longitudinal edge 21 of the saw blade 20. When the adjacent prism-shaped teeth 30, 30 have the same rising angle , the space S between the prism-shaped teeth 30, 30 becomes constant in the teeth rising direction, thereby solving the disadvantage that the space between the teeth becomes narrower from the tip ends toward the bases of the teeth.

(24) It should be noted that the term constant used for the rising angle does not mean a constant value in the strict sense. Similarly, the term same angle used for the rising angle does not have to be a same angle in the strict sense. For the term constant used for the space S between the adjacent prism-shaped teeth 30 as well, it does not have to be constant in the strict sense. These concepts each embrace more or less increase or decrease permitted based on the objects, functions, and effects of the present invention, which will be described later.

(25) The prism-shaped teeth 30 according to the first embodiment are triangular prism-shaped teeth made up of triangular prisms.

(26) A triangular prism-shaped tooth 30 has three lateral edges 30a, 30b, 30c and three lateral faces 31, 32, 33 which rise from the edge surface 21a of the longitudinal edge 21 of the saw blade 20.

(27) The triangular prism-shaped tooth 30 also has an obliquely cut end face 34 at its tip end obtained by obliquely truncating the triangular prism.

(28) The obliquely cut end face 34 has three edges 34a, 34b, and 34c. The edge 34a corresponds to the upper side of the lateral face 31, the edge 34b corresponds to the upper side of the lateral face 32, and the edge 34c corresponds to the upper side of the lateral face 33.

(29) A triangular prism-shaped tooth 30 has one of its lateral faces configured to be a flush lateral face 31 that rises flush with one surface, 20a or 20b, of a front surface 20a and a back surface 20b of the saw blade 20.

(30) The triangular prism-shaped teeth 30 are arranged alternately in opposite orientations one after another, such that the flush lateral faces 31 of the respective triangular prism-shaped teeth 30 become flush alternately with the front surface 20a and the back surface 20b of the saw blade 20.

(31) In each triangular prism-shaped tooth 30, the angle (lateral edge 30b) opposite the flush lateral face 31 is configured to be located in an intermediate position between the lateral edges 30a and 30c of the flush lateral face 31 in the longitudinal direction of the saw blade 20. In other words, the triangle of each triangular prism-shaped tooth 30 is shaped such that the crossing angles 1, 2 between the flush lateral face 31 and the respective adjacent lateral faces 32, 33 both become less than 90 degrees.

(32) In the case of the triangular prism-shaped teeth 30 in the first embodiment, the crossing angles 1 and 2 are set to be a same angle less than 90 degrees, so that the teeth each become an isosceles triangular prism-shaped tooth formed with the isosceles triangle which is bilaterally symmetrical.

(33) With the isosceles triangular prism-shaped teeth 30 adopted as the prism-shaped teeth, when the isosceles triangular prism-shaped teeth 30 are arranged in alternating orientations one after another on the longitudinal edge 21 of the saw blade 20, the lateral faces 32 and 33 facing each other and belonging respectively to the adjacent isosceles triangular prism-shaped teeth 30, 30 become parallel as seen in a plan view. That is, the space S between the adjacent isosceles triangular prism-shaped teeth 30 can be made constant in a plan view (in the direction perpendicular to the rising direction as well).

(34) Each triangular prism-shaped tooth 30, with the lateral edges 30a and 30c belonging to the flush lateral face 31, is configured such that a front vertical cutting edge VE1 is provided on the longer lateral edge 30a located frontward in a cutting direction D and a rear vertical cutting edge VE2 is provided on the shorter lateral edge 30c located rearward in the cutting direction D.

(35) Here, the cutting direction D refers to the direction in which the saw is pulled in the case of a pull-type saw. In the case of a push-type saw, it refers to the direction in which the saw is pushed.

(36) The edge angle of the front vertical cutting edge VE1 (or, the crossing angle 1 between the lateral faces 31 and 32) and the edge angle of the rear vertical cutting edge VE2 (or, the crossing angle 2 between the lateral faces 31 and 33) are both set to be an acute angle less than 90 degrees, preferably an acute angle less than 45 degrees.

(37) The front vertical cutting edge VE1 is a main vertical cutting edge that cuts a V-shaped groove into an object to be cut as the saw blade 20 moves in the cutting direction D. The rear vertical cutting edge VE2 is a subordinate vertical cutting edge relative to the front vertical cutting edge VE1, although it is able to make a V-shaped cut in the object as the saw blade 20 returns in the direction opposite to the cutting direction D.

(38) Each triangular prism-shaped tooth 30, with three edges 34a, 34b, 34c belonging to the obliquely cut end face 34 formed at its tip end, is configured such that a front horizontal cutting edge HE1 is provided on the edge 34b not belonging to the flush lateral face 31 and located frontward in the cutting direction D, and a rear horizontal cutting edge HE2 is provided on the edge 34c not belonging to the flush lateral face 31 and located rearward in the cutting direction D.

(39) The edge angle of the front horizontal cutting edge HE1 corresponds to a crossing angle between the obliquely cut end face 34 and the lateral face 32 functioning as the edge face of the front vertical cutting edge VE1. This crossing angle is set to be less than 90 degrees. The front horizontal cutting edge HE1 and the front vertical cutting edge VE1 meet at a tooth point P of the triangular prism-shaped tooth 30.

(40) As the saw blade 20 moves in the cutting direction D, the front horizontal cutting edge HE1 slices the surface of an object in an oblique horizontal direction, like chiseling. The rear horizontal cutting edge HE2 helps force the chips out of the cut groove of the object as the saw blade 20 moves in the direction opposite to the cutting direction D.

(41) In the present embodiment, the obliquely cut end face 34 is formed by truncating the prism obliquely downward at a constant inclination angle with the tooth point P as the apex. More specifically, the prism is truncated obliquely downward such that the slope of the edge 34b serving as the front horizontal cutting edge HE1 from the tooth point P becomes steeper than the slope of the edge 34a of the obliquely cut end face 34 from the tooth point P.

(42) It is needless to say that any angles may be adopted, as required, as the inclination angles with the tooth point P as the apex.

(43) Further, although not shown in the figure, a triangular prism-shaped tooth having an obliquely cut face that is cut in a manner different from the above-described obliquely cut end face 34 can also be adopted. Examples of such differently cut faces include an obliquely cut face (hereinafter, referred to as different-type obliquely cut end face) formed, with the distal end of the lateral edge 30b as an apex instead of the tooth point P (distal end of 30a), by truncating the prism obliquely downward from the apex, or, the distal end of the lateral edge 30b, at a constant inclination angle.

(44) This different-type obliquely cut face is more specifically configured such that the slope of the edge 34c from the distal end of the lateral edge 30b becomes steeper than the slope of the edge 34b that extends toward the tooth point P (distal end of 30a) from the distal end of the lateral edge 30b.

(45) A triangular prism-shaped tooth (similarly, a trapezoidal prism-shaped tooth described later) having this different-type obliquely cut end face is superior in the function of forcing the chips out of the cut groove of the object being cut. Such teeth can thus be added in places to the array of the triangular prism-shaped teeth 30 having the above-described obliquely cut end faces 34.

(46) Chips cut off by a triangular prism-shaped tooth 30 temporarily remain in the space S between the lateral face 32 of the triangular prism-shaped tooth 30 and its neighboring triangular prism-shaped tooth 30 in front. Each triangular prism-shaped tooth 30, however, is of the prism shape, having dimensions unchanged from the base toward the tip end of the tooth 30. Moreover, every triangular prism-shaped tooth 30 has a constant rising angle and rises in the same direction. For example, they all rise at a right angle in the same direction. Therefore, the space S between each pair of adjacent triangular prism-shaped teeth 30 becomes constant in the rising direction of the triangular prism-shaped teeth 30. That is, a sufficient space S is secured between the teeth 30 down to the bottom of the space S, without tapering toward the bottom. This fully eliminates the conventional disadvantage that the chips are forcibly pushed toward the bottom of the space S over time; substantially no chip clogging occurs over time. Accordingly, the saw keeps good cutting performance, which would otherwise deteriorate due to the chip clogging.

(47) The triangular prism-shaped tooth 30 is of the prism shape, with no reduction in dimensions from the base toward the tip end of the tooth. Thus, compared to the conventional triangular tooth, the obliquely cut end face 34 formed at the tip end of the tooth 30 can be made sufficiently large in area, and the horizontal cutting edges HE1 and HE2 formed on the obliquely cut end face 34 can be made sufficiently long in edge length. This ensures a sufficiently wide slicing width by the horizontal cutting edges HE1 and HE2, leading to improved slicing performance.

(48) Further, as the triangular prism-shaped tooth 30 is of the prism shape, compared to the conventional triangular tooth, a thin tooth with a smaller base can be used to form an obliquely cut end face 34 of the same area. Thus, in the case of arranging the teeth at the same pitch, the area of each obliquely cut end face 34 can be made large and the dimensions between the bases of the teeth can also be increased with the triangular prism-shaped teeth 30, than with the conventional triangular teeth. The greater clearance between the bases of the teeth means that chip clogging is less likely to occur. The larger area of the obliquely cut end face 34 means that the horizontal cutting edges HE1 and HE2 offer better slicing performance.

(49) On the other hand, when the dimensions between the teeth are made the same, compared to the conventional triangular teeth, a larger number of triangular prism-shaped teeth 30 can be arranged at a finer pitch, leading to a further improvement of the cutting performance of the saw.

(50) Further, with the isosceles triangular prism-shaped teeth adopted as the triangular prism-shaped teeth 30, the lateral faces 32 and 33 facing each other and belonging respectively to the adjacent prism-shaped teeth 30 become parallel as seen in a plan view. Thus, the dimensions of the space S become constant and unchanged in the direction perpendicular to the rising direction as well. This lessens uneven distribution of the chips within the space S, whereby more stable cutting operations and cutting performance can be expected.

(51) In the first embodiment, each triangular prism-shaped tooth 30 is configured such that, of its three lateral edges 30a, 30b, and 30c, two lateral edges 30a and 30c constitute lateral edges of the flush lateral face 31 that rises flush with one of the front and back surface 20a (20b) of the saw blade 20, and the remaining lateral edge 30b constitutes a lateral edge that rises flush with the other surface 20b (20a) of the saw blade 20. With this, it is configured such that each obliquely cut end face 34 becomes an oblique triangle that extends across the front and back surfaces 20a, 20b of the saw blade 20.

(52) With each obliquely cut end face 34 being configured as the oblique triangle extending across the front and back surfaces 20a, 20b of the saw blade 20, the horizontal cutting edges HE1, HE2 formed on the obliquely cut end face 34 each have the edge length (cutting edge length) that spans the entire thickness of the saw blade 20 between the front and back surfaces 20a and 20b.

(53) With the horizontal cutting edges HE1, HE2 formed on each obliquely cut end face 34 being made to traverse the entire thickness of the saw blade 20, during an operation of cutting an object, each horizontal cutting edge HE1, HE2 can shave the object over the entire area in the thickness direction of the saw blade 20.

(54) If each horizontal cutting edge HE1, HE2 extends to cover less than a half in thickness direction of the saw blade 20, the horizontal cutting edges HE1, HE2 will not be able to shave an object over the entire area in the thickness direction of the saw blade, in which case some part of the object may remain unshaved where the horizontal cutting edges only come into friction contact therewith. This is often the case with the conventional triangular teeth, and would lead to poor cutting performance and poor cutting efficiency.

(55) When each horizontal cutting edge HE1, HE2 extends to cover more than a half in thickness of the saw blade 20, with the triangular prism-shaped teeth 30 arranged alternately in opposite orientations one after another, each horizontal cutting edge HE1, HE2 can work together with the adjacent corresponding cutting edge as a pair, to shave the object over the entire area in the thickness direction of the saw blade 20, without leaving unshaved portions. According to the handsaw of the present invention, it is readily possible to increase the area of the obliquely cut end face 34, and it is also readily possible to cause each horizontal cutting edge HE1, HE2 to span more than a half in thickness direction of the saw blade 20. It however is more preferable that each horizontal cutting edge HE1, HE2 traverses the entire thickness of the saw blade 20 from the standpoint of cutting performance and also from the standpoint of strength of the tooth.

(56) A second embodiment of the present invention will be described with reference to FIG. 6.

(57) In the handsaw according to the second embodiment, trapezoidal prism-shaped teeth 140 are used as the prism-shaped teeth.

(58) The triangular prism-shaped tooth 30 according to the first embodiment described above has a base of a triangular shape. When a corner of this triangle opposite its base is cut off, the base of the prism attains a trapezoidal shape. The second embodiment has such trapezoidal prism-shaped teeth 140 arranged on an edge surface 121a of a longitudinal edge 121 of a saw blade 120.

(59) Each trapezoidal prism-shaped tooth 140 is configured such that, among four lateral edges 140a, 140b, 140c, and 140d on the prism, two lateral edges 140a and 140c constitute lateral edges of a flush lateral face 141 that rises flush with one of front and back surfaces 120a (120b) of the saw blade 120, and the remaining two lateral edges 140b and 140d constitute lateral edges of a second flush lateral face 145 that rises flush with the other of the front and back surfaces 120b (120a) of the saw blade 120. The second flush lateral face 145 is smaller in area than the flush lateral face 141.

(60) Each trapezoidal prism-shaped tooth 140 has two lateral faces 142, 143 in addition to the flush lateral face 141 and the second flush lateral face 145.

(61) The trapezoidal prism-shaped teeth 140 are configured such that they rise in a same direction from the edge surface 121a of the lateral edge 121 of the saw blade 120, or, such that their rising angles become constant. The rising angle of the trapezoidal prism-shaped teeth 140 in the second embodiment is 90 degrees, or, perpendicular. The rising angle of each trapezoidal prism-shaped tooth is not limited to the right angle; the teeth may be slanted as long as their angles are constant.

(62) The trapezoidal prism-shaped tooth 140 has an obliquely cut end face 144 at its tip end obtained by obliquely truncating the trapezoidal prism.

(63) The obliquely cut end face 144 has four edges 144a, 144b, 144c, and 144d. The edge 144a corresponds to the upper side of the flush lateral face 141, the edge 144b corresponds to the upper side of the lateral face 142, the edge 144c corresponds to the upper side of the lateral edge 143, and the edge 144d corresponds to the upper side of the second flush lateral face 145.

(64) The trapezoidal prism-shaped teeth 140 are arranged in alternating orientations one after another, such that their respective flush lateral faces 141 become flush alternately with the front surface 120a and the back surface 120b of the saw blade 120.

(65) In each trapezoidal prism-shaped tooth 140, the crossing angles 11, lag between the flush lateral face 141 and the respective adjacent lateral faces 142, 143 both become less than 90 degrees.

(66) In the case of the trapezoidal prism-shaped tooth 140 according to the second embodiment, it is configured as an isosceles trapezoidal prism-shaped tooth 140 with a base of a bilaterally symmetrical isosceles trapezoid.

(67) With the isosceles trapezoidal prism-shaped teeth 140 adopted, when the isosceles trapezoidal prism-shaped teeth 140 are arranged in alternating orientations one after another on the longitudinal edge 121 of the saw blade 120, the lateral faces 142 and 143 facing each other and belonging respectively to the adjacent isosceles trapezoidal prism-shaped teeth 140, 140 become parallel as seen in a plan view. That is, the space 1S between the adjacent isosceles trapezoidal prism-shaped teeth 140 can be made constant in a plan view (in the direction perpendicular to the rising direction as well).

(68) Each trapezoidal prism-shaped tooth 140, with the lateral edges 140a and 140c belonging to the flush lateral face 141, is configured such that a front vertical cutting edge 1VE1 is provided on the longer lateral edge 140a located frontward in the cutting direction D and a rear vertical cutting edge 1VE2 is provided on the shorter lateral edge 140c located rearward in the cutting direction D. The edge angle of the front vertical cutting edge 1VE1 (or, the crossing angle 11 between the lateral faces 141 and 142) and the edge angle of the rear vertical cutting edge 1VE2 (or, the crossing angle lag between the lateral faces 141 and 143) are both set to be an acute angle less than 90 degrees, preferably an acute angle less than 45 degrees.

(69) The rear vertical cutting edge 1VE2 is a subordinate vertical cutting edge relative to the front vertical cutting edge 1VE1, although it is able to make a V-shaped cut in the object as the saw blade 120 returns in the direction opposite to the cutting direction D.

(70) In each trapezoidal prism-shaped tooth 140, a front horizontal cutting edge 1HE1 and a rear horizontal cutting edge 1HE2 are provided on the edges 144b and 144c, respectively, of the obliquely cut end face 144 formed at the tip end of the tooth. The front horizontal cutting edge 1HE1 is located frontward in the cutting direction D, and is formed to obliquely traverse the thickness of the saw blade 120. The rear horizontal cutting edge 1HE2 is located rearward in the cutting direction D.

(71) The edge angle of the front horizontal cutting edge 1HE1 corresponds to a crossing angle between the obliquely cut end face 144 and the lateral face 142 functioning as the edge face of the front vertical cutting edge 1VE1. This crossing angle is set to be less than 90 degrees. The front horizontal cutting edge 1HE1 and the front vertical cutting edge 1VE1 meet at a tooth point 1P of the trapezoidal prism-shaped tooth 140.

(72) Chips cut off by a trapezoidal prism-shaped tooth 140 temporarily remain in the space 1S in front of the trapezoidal prism-shaped tooth 140. However, the space 1S between each pair of teeth 140 does not taper; rather, a sufficient space is secured to the bottom of the space 1S in accordance with the configuration described above. Accordingly, there occurs no degradation in cutting performance of the saw due to the chips pushed toward the bottom of the space 1S over time. The saw keeps good cutting performance.

(73) In the case of the trapezoidal prism-shaped teeth 140, compared to the triangular prism-shaped teeth 30, the teeth themselves can be increased in strength, although each tooth may take a longer width in the longitudinal direction of the saw blade 120.

(74) Other functions and effects of the handsaw using the trapezoidal prism-shaped teeth 140 are similar to the functions and effects described above for the handsaw using the triangular prism-shaped teeth 30.

(75) A third embodiment of the present invention will be described with reference to FIG. 7.

(76) The handsaws according to the first and second embodiments described above have right prism-shaped teeth as the prism-shaped teeth 30 and 140, respectively. The triangular prism-shaped teeth 30 and the trapezoidal prism-shaped teeth 140 both rise at a right rising angle from the edge surface 21a (121a) of the longitudinal edge 21 (121) of the corresponding saw blade 20 (120).

(77) A handsaw according to the third embodiment has oblique prism-shaped teeth 250 which rise at an oblique rising angle from an edge surface 221a of a longitudinal edge 221 of a saw blade 220.

(78) The rising angle of the oblique prism-shaped teeth 250 is often set as a constant angle slightly inclined toward the cutting direction D of the handsaw from the right angle, besides the right angle of 90 degrees. With the rising angle thus set constant, the space 2S between the adjacent oblique prism-shaped teeth 250, 250 becomes constant in the rising direction of the teeth 250. This prevents the space 2S from tapering toward the bases of the teeth, and ensures that the space 2S with sufficient dimensions is secured.

(79) Although the rising angle of the oblique prism-shaped teeth 250 is not necessarily limited, it is preferably set within 30 degrees from the perpendicular direction (90 degrees).

(80) Other features of the handsaw of the third embodiment having the oblique prism-shaped teeth 250 are similar to those of the handsaw of the first embodiment.

(81) The reference characters with any number from 30 to 39 for the right triangular prism-shaped tooth 30 in the first embodiment, the lateral faces 31, 32, 33, obliquely cut end face 34, lateral edges 30a, 30b, 30c, and edges 34a, 34b, 34c correspond respectively to lateral faces 251, 252, 253, obliquely cut end face 254, lateral edges 250a, 250b, 250c, and edges 254a, 254b, 254c of the oblique triangular prism-shaped tooth 250.

(82) Further, the reference characters for the space 2S, vertical cutting edges 2VE1, 2VE2, horizontal cutting edges 2HE1, 2HE2, and apex 2P are identical to those used in the first embodiment.

(83) A fourth embodiment of the present invention will be described with reference to FIG. 8.

(84) The handsaw in the fourth embodiment uses triangular prism-shaped teeth (see FIG. 8 (A)) or trapezoidal prism-shaped teeth (see FIG. 8 (B)) as the prism-shaped teeth, which are similar to the triangular prism-shaped teeth 30 and 250 according to the first and third embodiments and to the trapezoidal prism-shaped teeth 140 according to the second embodiment.

(85) On the other hand, in the handsaw according to the fourth embodiment, the triangular prism-shaped teeth 360, 360 (see FIG. 8 (A)) or the trapezoidal prism-shaped teeth 470, 470 (see FIG. 8 (B)) are arranged relatively densely. This results in a configuration in which a tooth 360 (470) closer to the front in the longitudinal direction of the saw blade 320 (420) has its rear end 360re (470re) located behind a front end 360fe (470fe) of another tooth 360 (470) immediately behind the tooth 360 (470). The space 3S (4S) thus has its major part hidden behind the tooth 360 (470). With this configuration as well, the space 3S (4S) is kept constant in width in the rising direction of the teeth 360 (470), instead of the space 3S (4S) being narrowed toward the bases of the teeth. Such a handsaw according to the fourth embodiment is also within the scope of the present invention.

(86) A fifth embodiment of the present invention will be described with reference to FIG. 9.

(87) The handsaw in the fifth embodiment also uses triangular prism-shaped teeth (see FIG. 9 (A)) or trapezoidal prism-shaped teeth (see FIG. 9 (B)) as the prism-shaped teeth, which are similar to the triangular prism-shaped teeth 30 and 250 according to the first and third embodiments and to the trapezoidal prism-shaped teeth 140 according to the second embodiment.

(88) On the other hand, in the handsaw according to the fifth embodiment, the triangles of the triangular prism-shaped teeth 580 (see FIG. 9 (A)) and the trapezoids of the trapezoidal prism-shaped teeth 690 (see FIG. 9 (B)) are small in size; they do not extend from the front surface 520a (620a) to the back surface 520b (620b) of the saw blade 520 (620).

(89) Even such triangular prism-shaped teeth 580 and the trapezoidal prism-shaped teeth 690, not extending across the front and back surfaces 520a (620a) and 520b (620b) of the saw blade 520 (620), are considered to be the teeth applicable to the handsaw of the present invention, from the standpoint that they have the functions as the prism-shaped teeth.

(90) With the triangular prism-shaped teeth 580 or the trapezoidal prism-shaped teeth 690 which are not formed over the entire area in the thickness direction of the saw blade 520 (620), however, the horizontal cutting edges 5HE1, 5HE2 (6HE1, 6HE2) formed on their obliquely cut end faces are not formed over the entire area in the thickness direction of the saw blade 520 (620) either. The saw thus has a portion within the thickness of the saw blade 520 (620) in which it cannot cut an object with the horizontal cutting edges 5HE1, 5HE2 (6HE1, 6HE2). This leads to degradation in cutting performance of the handsaw.

(91) It is thus preferable, as shown in FIGS. 9 (A) and (B), that the triangle of each triangular prism-shaped tooth 580 and the trapezoid of each trapezoidal prism-shaped tooth 690 have a size that is at least greater than a half in the thickness direction of the saw blade 520 (620).

(92) With the triangle of the triangular prism-shaped tooth 580 or the trapezoid of the trapezoidal prism-shaped tooth 690 having a size that exceeds a half in the thickness direction of the saw blade 520 (620), when the triangular prism-shaped teeth 580 or the trapezoidal prism-shaped teeth 690 are arranged in alternating orientations one after another, it is ensured that, with preceding and trailing teeth 580 and 580 (690 and 690) as a pair, there is no portion within the thickness of the saw blade 520 (620) in which the saw is unable to cut an object.

(93) It can be said that it is of course preferable that the triangle or the trapezoid is formed to extend across the saw blade 520 (620) in its thickness direction from the front surface 520a (620a) to the back surface 520b (620b), as in the cases of the triangular prism-shaped teeth 30, 250 and the trapezoidal prism-shaped teeth 140 shown in FIGS. 2 (A), 4 (A), 6 (A), and 7 (A).

(94) A description will further be made primarily about the permissible ranges for the dimensional relationships among the parts constituting the handsaw according to each embodiment of the present invention.

(95) First, the rising angle of each prism-shaped tooth 30 (140, 250) from the edge surface 21a (121a, 221a) of the longitudinal edge 21 (121, 221) of the saw blade 20 (120, 220) will be mentioned. The rising angle may be set to, for example, 90 degrees (perpendicular), or a constant angle tilted by a certain angle in the longitudinal direction. The constant rising angle , however, is not required to be a strictly precise angle for all the prism-shaped teeth 30 (140, 250) being arranged. For each prism-shaped tooth 30 (140, 250) arranged, the rising angle with a difference within 10 degrees is considered to be within tolerance, and is included in the constant rising angle . The difference within 10 degrees of the rising angle of each prism-shaped tooth 30 (140, 250) results in an enlargement or reduction of the space S (1S, 2S) between the adjacent prism-shaped teeth 30 (140, 250), within 20 degrees in the rising direction of the space S (1S, 2S). The variation within such a range, however, does not create an adverse result that the spaces S (1S, 2S) between the teeth are clogged with chips, or does not adversely affect the cutting performance of the saw.

(96) Alternatively, the prism-shaped teeth 30 (140, 250) may be arranged such that the rising angle changes gradually in the longitudinal direction of the saw blade 20 (120, 220). In such a case, it is expected that the tooth on one end and the tooth on the other end in the longitudinal direction of the saw blade 20 (120, 220) will have their rising angles considerably different from each other. For a respective pair of adjacent prism-shaped teeth 30 (140, 250), however, their rising angles are almost the same. In this case, it can be said that the space S (1S, 2S) between the adjacent prism-shaped teeth 30 (140, 250) is substantially constant in the teeth rising direction. Thus, such a teeth arrangement is also within the scope of the present invention.

(97) The space S (1S, 2S) between the adjacent prism-shaped teeth 30 (140, 250) will be mentioned. For this space S (1S, 2S) as well, although the space S (1S, 2S) is set to be constant in the rising direction, any space with an increase within 20 degrees in angle or a reduction within 20 degrees in angle can be considered to be within a permissible range, and included in the constant space. This is because, when the rising angle of each prism-shaped tooth 30 (140, 250) has a difference within 10 degrees, the space S (1S, 2S) between the prism-shaped teeth correspondingly increases or decreases within 20 degrees in angle in the rising direction. The enlargement or reduction of the space S (1S, 2S) within such a range, however, does not create an adverse result that the spaces S (1S, 2S) between the teeth are clogged with chips, or does not adversely affect the cutting performance of the saw.

(98) It is more preferable that the variation in the rising angles of the prism-shaped teeth 30 (140, 250) is within 5 degrees. That is, it is more preferable that the rising angles of the prism-shaped teeth 30 (140, 250) are set to be constant with a tolerance of 5 degrees. Correspondingly, it is preferable that the space S (1S, 2S) between the adjacent prism-shaped teeth 30 (140, 250) is set to be constant including an increase within ten degrees in angle and a reduction within ten degrees in angle in the rising direction. When the changes in the spaces S (1S, 2S) between the prism-shaped teeth are within the permissible range of ten degrees in the rising direction, chip clogging in the spaces S (1S, 2S) between the teeth can be prevented sufficiently effectively, making it possible to keep sufficiently good cutting performance. Accordingly, any handsaws using the prism-shaped teeth falling within the permissible ranges as described above are also within the scope of the present invention.

(99) For each of the lateral faces 31, 32, 33 (141, 142, 143, 145, 251, 252, 253) of the respective prism-shaped teeth 30 (140, 250), the lateral edges on its both sides, i.e. 30a and 30c, 30a and 30b, 30b and 30c (140a and 140c, 140a and 140b, 140b and 140d, 140c and 140d, 250a and 250c, 250a and 250b, 250b and 250c), are configured to be parallel to each other. However, they do not have to be precisely parallel; they may be configured to rise obliquely at a crossing angle of within 10 degrees from the parallel. That is, the present invention embraces the case where the lateral edges of each lateral face rise obliquely at a crossing angle of within 10 degrees from the parallel.

(100) Although it is necessary in a strict sense that the lateral edges of every lateral face are parallel to each other in the prism-shaped teeth 30 (140, 250), when the displacement from the parallel is relatively small, or, when the displacement is within 10 degrees from the parallel, then the teeth can exert the geometric characteristics as the prism-shaped teeth. They do not create an adverse result that the spaces between the teeth are clogged with chips, or do not adversely affect the cutting performance of the saw. Accordingly, the prism-shaped teeth falling within such a range are also regarded as the prism-shaped teeth of the present invention.

(101) It is preferable that, for each of the lateral faces 31, 32, 33 (141, 142, 143, 145, 251, 252, 253) of the respective prism-shaped teeth 30 (140, 250), the lateral edges on its both sides, i.e. 30a and 30c, 30a and 30b, 30b and 30c (140a and 140c, 140a and 140b, 140b and 140d, 140c and 140d, 250a and 250c, 250a and 250b, 250b and 250c), are configured to be parallel to each other, or if not parallel, at a crossing angle of within 5 degrees from the parallel. This is because, when the reduction or enlargement of each of the prism-shaped teeth in the rising direction of the prism falls within the range of 5 degrees, the teeth can sufficiently exert the geometric characteristics as the prism-shaped teeth, and it is possible to sufficiently effectively prevent chip clogging in the spaces between the teeth, and to keep sufficiently favorable cutting performance of the saw.

(102) It should be noted that the thickness of the saw blade 20 (120, 220, 320, 420, 520, 620) itself may be slightly increased near the edge of the saw blade where the teeth 30, 140, 250, 360, 470, 580, or 690 are to be formed, compared to the middle of the saw blade. This is for the purposes of reducing friction between the saw blade 20 (120, 220, 320, 420, 520, 620) and the object to be cut during the cutting operation. When such a configuration is adopted, each tooth 30, 140, 250, 360, 470, 580, or 690 may become a mushroom-shaped prism tooth which slightly expands from the base toward the tip end of the tooth like a mushroom. The prism tooth of such a mushroom shape is also regarded as the prism-shaped tooth according to the present invention.

INDUSTRIAL APPLICABILITY

(103) The handsaw according to the present invention has an industrial application as means for manually cutting wood, plastic, or other objects.

DESCRIPTION OF THE REFERENCE CHARACTERS

(104) 10 grip 20 saw blade 20a front surface of saw blade 20b back surface of saw blade 21 longitudinal edge of saw blade 21a edge surface of longitudinal edge of saw blade 30 triangular prism-shaped tooth 30a to 30c lateral edge of triangular prism-shaped tooth 31 flush lateral face of triangular prism-shaped tooth 32, 33 lateral face of triangular prism-shaped tooth 34 obliquely cut end face 34a to 34c edge 140 trapezoidal prism-shaped tooth 140a to 140d lateral edge of trapezoidal prism-shaped tooth 141 flush lateral face of trapezoidal prism-shaped tooth 142, 143 lateral face of trapezoidal prism-shaped tooth 144 obliquely cut end face 144a to 144d edge 145 second flush lateral face of trapezoidal prism-shaped tooth 250 oblique prism-shaped tooth 250a to 250c lateral edge of oblique prism-shaped tooth 251 flush lateral face of oblique prism-shaped tooth 252, 253 lateral face of oblique prism-shaped tooth 254 obliquely cut end face 254a to 254c edge 360 triangular prism-shaped tooth 360fe front end 360re rear end 470 trapezoidal prism-shaped tooth 470fe front end 470re rear end 580 triangular prism-shaped tooth 690 trapezoidal prism-shaped tooth 1, 2 crossing angle of flush lateral face with respective 11, lag adjacent lateral face rising angle D cutting direction P, 1P, 2P, 7P, 8P apex S, 1S, 2S, 3S, 4S, 5S, 6S space VE1, 1VE1, 2VE1 front vertical cutting edge VE2, 1VE2, 2VE2 rear vertical cutting edge HE1, 1HE1, 2HE1, 5HE1, 6HE1 front horizontal cutting edge HE2, 1HE2, 2HE2, 5HE2, 6HE2 rear horizontal cutting edge