WO2008011685A2

WO2008011685A2 - Blade apparatus

Info

Publication number: WO2008011685A2
Application number: PCT/AU2007/001432
Authority: WO
Inventors: Lajos Miklos Czukelter
Original assignee: Scott, Walter, Hume; Collingwood, Donald
Priority date: 2006-07-27
Filing date: 2007-09-27
Publication date: 2008-01-31
Also published as: WO2008011685A3

Abstract

The present invention relates to a blade tool. There is provided a blade tool apparatus that may include a pair of substantially planar, elongate blade portions (11 & 12) each having a working edge (13 & 15) formed on a long edge spaced from a back edge and having a free end, the respective blade portions being joined along a line (18) extending from a point of intersection of said working edges, the point of intersection of working edges being spaced from a first said free end to provide a cutting stroke for its respective said working edge.

Description

BLADE APPARATUS FIELD OF THE INVENTION This invention relates to a blade apparatus. This invention has particular but not exclusive application to a blade apparatus for saw-cutting right angles into plywood or the like, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as performing progressive cuts at angles in any sheet-like material generally.

PRIOR ART In timber work plywood or other sheet material may require internal right angle cuts. Generally this involves the drilling of a hole at the point of the change of cut direction internal of the sheet edge. The first cut may be from the sheet edge to the hole, cutting from the edge to the hole, or may be initiated from the hole. After the first cut, the second cut is initiated by altering the cut direction to cut away from the hole in the new direction. This results in a radius at the point of change of direction of the cut. The radius corresponds to a diameter that is comparable to the depth of the saw blade. Accordingly, it may be a relatively large radius. The method is only suited to situations where the included material between the cuts is to be removed. When material is to be removed, the internal radius may be squared off to disguise the method of formation. However, if the material were to be retained, the method cannot work. DESCRIPTION OF INVENTION

In one aspect the present invention resides broadly in blade apparatus including: an initiating blade portion having an elongate cutting edge for forming a first cut in a material; a secondary blade portion extending from an end of the initiating blade portion and having a secondary cutting edge intersecting and extending away from said initiating cutting edge, the plane of the initiating blade portion making a selected angle with the plane of the secondary blade portion, and a stiffening portion extending in the plane of, and from one end of, the initiating blade portion and supporting said secondary blade portion along an elongate side edge thereof opposite said secondary cutting edge. The respective cutting edge portions may be saw-tooth edges. The rake of the respective saw tooth portions may be in the same or opposite directions. The saw teeth may be of the same or different set. The respective initiating and secondary blade portions may comprise a pair of substantially planar blade portions each having a working edge, the respective blade portions being joined along a line extending from a point of intersection of said working edges, the point of intersection of working edges being spaced from a first said free end to provide a cutting stroke for its respective said working edge.

The blade portions may be of steel or the like. The blade portions may be formed by bending of a single parallel edged steel strip or may be fabricated from two appropriately shaped parts by welding. In the case of folding from a single strip, this may be configured with saw teeth before folding. In this case the two portions will meet at a selected angle such as a right angle, but the respective working edges will meet in different but intersecting planes. One advantage for angling the respective planes is to provide for a clearing-out relief at the point of transition in use, whereby the edge that has made the first cut is angled away from the cut work to engage the edge for the second cut. If the blade portions are formed from a single blade including saw teeth, a number of saw teeth may be removed from the point of transition.

The blade portions may be of any appropriate length. They may be of equal length or of different lengths with respect to each other.

The working edges may be provided with saw teeth before or after forming or fabrication. Alternatively, the working edge may be a diamond saw or blade edge. The invention will be described hereinafter with reference to saw-tooth working edges. The working edges may be of any appropriate length. They may be of equal length or of different lengths with respect to each other.

The blade portions may be post treated to harden the teeth after forming up in an annealed state. The blade portions are preferably of stock and tooth set comparable to conventional blades, such as 1.2 mm, in order that cuts may be indistinguishably continued.

The free end of one or both blade portions may be configured to accept a handle. One or both of the handles may be selectively detachable. The apparatus may be adapted to fit any appropriate saw apparatus including a bow frame, sabre, or jigsaw. The respective blade portions may be joined along a line defined by the intersection of the planes containing the respective blade portions. The planes may project at right angles in order to provide for cutting into and across a sheet with the cut forming an included right angle. However, the planes may intersect at other than right angles to form cuts having different included angles. In cases where the planes are not at right angles, the cutting and back edges may both be toothed to provide a tool capable of cutting complementary angles.

The saw teeth may be of reducing height and/or lesser pitch in the region of the point of intersection of said long cutting edges. The saw teeth are preferably selected from a metal saw tooth, a rip saw tooth or a chisel point saw tooth profile.

The intersection of the long back edges is preferably spaced from the adjacent free end to permit continuation of the cut started by formation of the included angle of cuts in the sheet. The long back edges may also form a second set of toothed edges to make a reversible tool. While larger angles are appropriate, preferably the respective long cutting edges may meet at an included angle of less than 10°, and more preferably between 2° and 7°.

In a further aspect this invention resides broadly in blade apparatus including a saw blade body having an elongate cutting edge opposite a back edge, an initiating blade portion for forming a first cut in a material being defined on one end portion of the saw blade body, and a secondary blade portion being formed along a line extending from said cutting edge adjacent said initiating blade portion to said back edge at a location remote from said initiating blade portion, the plane of the initiating blade portion making a selected angle about said line with the plane of the secondary blade portion.

The blade may be formed of a bimetallic strip wherein the metal of the cutting edge is hardened after folding.

In use the initial saw cut may be made by the portion between the free end that the intersection of the long cutting edges, or may be made by a separate conventional saw. The change of direction of the cut may then be achieved by repetitively advancing the saw, engaging the intersection region until the next blade portion is cutting the second cut. Once enough of a cut is advanced to permit insertion of a conventional saw, this may be used to expedite completion of the second cut. The process may be continued with the same or different examples of the present invention, to cut left or right, or at an angle other than a right angle, as the job requires. Alternatively the first cut may be initiated by the machine end of a sabre saw embodiment to enable use of the machine guide plate, followed by drawing the secondary blade into use to make the second cut.

In a further aspect the present invention resides broadly in a sabre saw blade including: an elongate initiating blade extending from a tool mounting end and having an initiating cutting edge for forming a first cut in a material, and a secondary blade portion extending along an edge of a stiffening portion of said initiating blade defined beyond the initiating cutting edge, the plane of the secondary blade portion making a selected angle with the plane of the initiating blade, the secondary blade cutting edge extending from the end of the initiating cutting edge and inclining away from said edge.

In this embodiment the initial cut utilizes the end of the blade fixed to the machine, the guide plate being used as per a normal sabre saw cut. After the first cut the secondary cut is started by drawing the machine out of the work until the lead teeth of the secondary cutting edge engage and cut the sheet.

The tooth rake of the secondary blade cutting edge may be the same as or opposite the tooth rake of the initiating cutting edge. The initiating cutting edge may have the teeth raked toward from the tool to urge the tool toward the work during the initial cutting phase, as per heavy duty sabre saw blades. Alternatively, the initiating cutting edge may have the teeth raked away from the tool, as per jig saw blades.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a preferred embodiment of the invention and wherein:

FIG. 1 is a perspective view of apparatus in accordance with the present invention;

FIG. 2 is a perspective view of apparatus in accordance with a further embodiment of the present invention; and

FIG. 3 is a perspective view of apparatus in accordance with a yet further embodiment of the present invention;

In the FIG. 1 there is provided a blade 10 including a first blade portion 11 of steel having TIG welded thereto a second steel blade portion 12. The first blade portion 11 has a working edge 13 provided with saw teeth at one end.

The second blade portion 12 tapers to meet the end of the saw teeth array, the second blade portion having a working edge 15 with saw teeth formed thereon. Diminishing teeth 17 are provided as the taper of the second blade portion approaches the first blade portion. The first blade portion 11 is provided with engagement holes 16 adapted to receive removable handles (not shown).

The first and second blade portions (11 and 12 respectively) are joined along a line 18 extending from a point of intersection 19 of the working edges (13 and 15).

In use, a first saw fine is formed in a work piece by the first blade portion 11 until a change of direction is to be pursued. Thereafter the second blade portion 12 is worked into the job to form a corner. The new cut direction may then be continued by the second blade portion 12 or maintained by conventional means.

In the embodiment of FIG. 2, a bimetal hacksaw blade 20 is folded about a fold line 21 to form a first blade portion 22 and a second blade portion 23. The fold is formed before the hardening of the respective first 24 and second 25 cutting edge teeth. The included angle between the first blade portion 22 and second blade portion 23 is 90° transverse the fold line 21.

The blade 20 is mounted by leading 26 and trailing 27 pin holes adapted to support the blade 20 by the leading and trailing pins respectively of a conventional hacksaw frame (not shown).

In use the first cut from the edge of a sheet material is made by the first blade portion 22. When the first cut is made to a selected distance, the second blade portion 23 is worked into the piece until the 90° cut is as long as the blade is wide. Thereafter the second blade portion may be worked over its length up to the extremity of the fold line to continue the second cut or may be removed and replaced by a conventional blade.

In the embodiment of FIG. 3, there is provided a sabre saw blade 30 having a blade body 31 extending from a mounting end 32 adapted to mount to a sabre saw body (not shown) to an outer end 33. The inner portion of the blade body 31 is provided with an initial-cut, saw-toothed edge 34.

Fabricated to the outer portion of the blade body 31 by welding and finishing is a secondary blade portion 35 having a secondary toothed cutting, edge 36.

In use the sabre type blade is first operated with the machine foot plate resting on the sheet material and the initial cut edge 34 working in from the sheet edge for a selected distance. Thereafter the machine is withdrawn from the work and operated to work the secondary blade portion 35 through the piece to form a right-angle cut. Thereafter he cut is continued with a conventional blade.

It will of course be realised that while the above has been given by way of illustrative example of this invention, all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as defined in the following claims.

Claims

CLAIM

1. Blade apparatus including: an initiating blade portion having an elongate cutting edge for forming a first cut in a material; a secondary blade portion extending from an end of the initiating blade portion and having a secondary cutting edge intersecting and extending away from said initiating cutting edge, the plane of the initiating blade portion making a selected angle with the plane of the secondary blade portion, and a stiffening portion extending in the plane of, and from one end of, the initiating blade portion and supporting said secondary blade portion along an elongate side edge thereof opposite said secondary cutting edge.

2. Blade apparatus according to claim 1 , wherein the respective cutting edge portions are saw-tooth edges.

3. Blade apparatus according to claim 2, wherein the rake of the respective saw tooth portions are in the same direction.

4. Blade apparatus according to claim 1 , wherein the respective blade portions are joined along a line extending from a point of intersection of said cutting edges, the point of intersection of cutting edges being spaced from a first said free end to provide a cutting stroke for its respective said working edge.

5. Blade apparatus according to claim 1, wherein the blade portions are steel or the like.

6. Blade apparatus according to claim 1 , wherein the blade portions are formed by bending of a single parallel edged steel strip.

7. Blade apparatus according to claim 6, wherein the steel strip is configured with saw teeth before folding.

8. Blade apparatus according to claim 7, wherein a number of saw teeth are removed from the point of transition between the respective cutting edges.

9. Blade apparatus according to claim 6, wherein the steel strip is a bimetallic strip wherein the metal of the cutting edge is hardened after folding.

10. Blade apparatus according to claim 1 , wherein the free end of one or both blade portions is configured to accept a handle.

11. Blade apparatus according to claim 1 , wherein apparatus is adapted to fit saw apparatus selected from a bow frame, sabre, or jigsaw.

12. Blade apparatus according to claim 1 , wherein the respective blade portions are joined along a line defined by the intersection of the planes containing the respective blade portions, the planes meeting at right angles in order to provide for cutting into and across a sheet with the cut forming an included right angle.

13. Blade apparatus according to claim 1 , wherein the saw teeth are of reducing height and lesser pitch in the region of the point of intersection of the respective cutting edges.

14. Blade apparatus including a saw blade body having an elongate cutting edge opposite a back edge, an initiating blade portion for forming a first cut in a material being defined on one end portion of the saw blade body, and a secondary blade portion being formed along a line extending from said cutting edge adjacent said initiating blade portion to said back edge at a location remote from said initiating blade portion, the plane of the initiating blade portion making a selected angle about said line with the plane of the secondary blade portion.

15. Blade apparatus according to claim 14, wherein the blade is formed of a bimetallic strip wherein the metal of the cutting edge is hardened after folding.

16. A sabre saw blade including: an elongate initiating blade extending from a tool mounting end and having an initiating cutting edge for forming a first cut in a material, and a secondary blade portion extending along an edge of a stiffening portion of said initiating blade defined beyond the initiating cutting edge, the plane of the secondary blade portion making a selected angle with the plane of the initiating blade, the secondary blade cutting edge extending from the end of the initiating cutting edge and inclining away from said edge.

17. A sabre saw blade according to claim 16, wherein the tooth rake of the secondary blade cutting edge is opposite the tooth rake of the initiating cutting edge.

18. A sabre saw blade according to claim 16, wherein the tooth rake of the initiating cutting edge has the teeth raked toward the tool to urge the tool toward the work during the initial cutting phase.