NZ627807A - Blade for a reciprocating saw and handsaw - Google Patents

Abstract

A blade 10 suitable for a handheld reciprocating saw 12, comprises a number of forward facing blades 16 configured to cut in a first direction of movement A, and a number of backward facing blades 18 configured to cut in a second direction B. The teeth are arranged along the cutting edge of the blade 10 in alternating groups of like teeth. The length of the blade 10 is greater than its height.

Description

BLADE FOR A RECIPROCATING SAW AND HANDSAW FIELD OF THE INVENTION The present invention relates to a blade for a reciprocating saw and a saw. More particularly, but not exclusively, the present ion relates to blade for a hand saw and a hand saw.

BACKGROUND OF THE INVENTION Most saw blades cut in a forward direction (push stroke) with a passive or non-cutting return stroke while some saws cut in a reverse direction (pull stroke) with a passive forward stroke. Owing to the passive stroke, approximately 50% of the effort required in operating the saw does not provide a cutting action which removes material.

Cutting teeth of reciprocating saw blades can become clogged, thereby ng g ncy so that more energy is required to complete a cut. An inefficient saw can be impractical for extended use. Previously proposed reciprocating saw blades which are configured to reduce clogging are generally ineffective and can be difficult and/or expensive to manufacture.

Examples of the invention seek to improve, or at least ameliorate, one or more antages of previous ocating saw blades.

SUMMARY OF THE INVENTION ing to the present invention, there is ed a blade for a handheld reciprocating saw, comprising a plurality of forward facing teeth configured for cutting in a first ion of movement and a plurality of backward facing teeth configured for cutting in a second direction of movement, the teeth being arranged along a cutting edge of the blade in alternating groups of like teeth, wherein the length of the blade is greater than the height of the blade.

According to a preferred embodiment, each group comprises 5 to 30 teeth. Preferably, each group has the same number of teeth.

Preferably, each group is separated by an opening formed in the blade.

According to the invention there is also provided a saw comprising a blade of the above described type.

According to a preferred ment, the saw further comprises a handle which is arranged at an angle to the blade, the angle between the cutting edge and the blade being in the range of 40 to 60 degrees.

Preferably, the saw is configured for use as a hand saw or a powered saw.

BRIEF DESCRIPTION OF THE DRAWINGS red embodiments of the invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: Figure 1 is a side view of a hand saw of an embodiment of the invention; and Figure 2 is a close-up view of teeth of the hand saw.

DETAILED PTION A blade 10 according to a preferred embodiment of the present invention is illustrated in Figure 1. The blade 10 is configured for use in a reciprocating saw 12 which es a handle 14.

As illustrated in Figure 2, the blade 10 ses a plurality of forward facing teeth 16 configured for cutting in a first direction of movement A which is generally forward or \lntmn'o\'m‘NRPortbl\DCC\MZI\86 l 3 369_1.d0c-2|/10/2015 away from a user. The blade 10 also comprises a plurality of backward facing teeth 18 configured for cutting in a second direction of movement B which is backward or toward a user. The teeth 16, 18 are arranged along a cutting edge of the blade in alternating groups of like teeth. In this regard, a group of forward facing teeth 16 is provided and either side of this group of teeth, along a cutting edge of the blade, there is formed a group of rearward facing teeth 18. This ating pattern may be repeated along the length of the cutting edge, though it will be appreciated that the groups may be otherwise arranged. For example, one or more groups of forward facing teeth 16 may be further split into smaller groups of teeth and, similarly, one or more groups of rearward facing teeth 18 may be split into smaller groups of teeth, and these smaller groups may be disposed at different locations along the cutting edge of the blade 10 so as to break up the alternating pattern of teeth.

The ant has found that providing alternating groups of forward facing and rd facing teeth may result in superior performance when compared with us ws.

Although not wishing to be bound by any particular theory, it is believed that the first tooth in any group may only lly cut fibres of the material being cut and the following tooth or teeth further progress the cut. Accordingly, a group of teeth is required to efficiently cut a material. However, as the number of teeth in a group increases, ged fibres tend to gather between teeth and clog the blade and reduce the efficiency of the cutting teeth.

Accordingly, it is desirable to limit the number of teeth in a group so as to reduce clogging.

Not only do the rd facing teeth work to move the dislodged fibres away from the cut to unclog the cutting teeth but they also allow the blade to cut on a rearward stroke, thereby increasing the cutting efficiency of the saw owing to the teeth “clusters” that cut on both forward and reverse strokes.

Furthermore, producing groups of teeth, as opposed to individually alternating forward and rearward facing teeth, is believed to be easier using conventional manufacturing ses.

According to the embodiment illustrated, each group comprises 20 teeth, though it will be appreciated that satisfactory performance may similarly be achieved with groups of teeth HIananemvvmWRPmleCCmmél3369_l decal/100.015 of other numbers, such as groups of 5 to 30 teeth for example. In the rated embodiment, each group has the same number of teeth, though it will be appreciated that groups of different numbers of teeth may similarly be provided. In one e, groups of teeth toward a forward end of the blade 10 may have more teeth than groups toward a rearward end of the blade 10. Furthermore, groups of d facing teeth 16 may be larger toward the d end of the blade 10 and groups of rearward facing teeth 18 may be larger in number toward the rearward end of the blade.

To further improve the ng properties of the blade, each group of teeth may be separated by an opening 20 or 22 formed in the blade. The opening 20, 22 may be formed in a gap between each group of teeth and extend below the root of the teeth to provide a passage through which ged fibres can pass to prevent clogging of the blade. As illustrated in Figure 2, a base or portion of the opening which is fiirthermost from the root may be curved so as to reduce the chance of cracks forming in the blade. It will be appreciated that the opening 20, 22 may be in the form of a notch, slot, recess or void. It will also be appreciated that opening 20 will be formed ently from opening 22 as opening 22 will have teeth extending toward the opening while opening 20 will have teeth extending away therefrom.

In the described embodiment, the blade 10 is configured for use in a hand saw 10 which is configured for reciprocating use by a person. It will be appreciated that the blade 10 may also be used in reciprocating cutting machines or powered saws such as jigsaws.

Furthermore, the teeth 16, 18 of the illustrated handsaw are configured for g wood and it will be iated that the teeth may be otherwise configured for cutting other materials, such as plastics or metallic materials. In this regard, the teeth may be smaller and placed closer together for cutting materials such as steel.

As illustrated in Figure 1, the handle 14 of the handsaw 10 may be arranged at a more acute or relaxed angle when compared to conventional handsaws. In this regard, the handle 14 is arranged generally along a line E, which is at an angle a to the cutting edge of the blade or a line D which extends along tips of the teeth 16, 18. Owing to the improved cutting efficiency of the w 10, the handle 14 may be more acute or relaxed e the downward cutting force required to complete a cut is reduced. Furthermore, the acute angle may improve control of the saw 12. The angle a may be varied ing to the preferences of a user, though is preferably in the range of 40 to 60 degrees.

The blade 10 may be formed from commercially ble materials such as hardened steel and formed using conventional manufacturing processes such as stamping or forging.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. It will be apparent to a person d in the nt art that various changes in form and detail can be made therein without ing from the spirit and scope of the invention. Thus, the present invention should not be limited by any of the above described exemplary embodiments.

The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

THE

Claims (10)

CLAIMS 1. NG THE INVENTION ARE AS FOLLOWS:
1. l. A blade for a handheld ocating saw, comprising a plurality of forward facing teeth configured for cutting in a first ion of movement and a plurality of backward facing teeth configured for cutting in a second direction of movement, the teeth being arranged along a cutting edge of the blade in alternating groups of like teeth, wherein the length of the blade is greater than the height of the blade.
2. 2. A blade as claimed in claim 1, whereby in use the plurality of teeth engage a work 10 piece to either cut or clear debris as the blade is drawn across the work piece.
3. 3. A blade as claimed in claim 1 or claim 2, wherein each group comprises 5 to 30 teeth. 15
4. 4. A blade as claimed in any preceding claim, wherein each group has the same number of teeth.
5. 5. A blade as d in any preceding claim, n each group is separated by an opening formed in the blade.
6. 6. A blade as claimed in any preceding claim, r comprising a handle which is arranged at an angle to the cutting edge blade, the angle between the cutting edge and the blade being in the range of 40 to 60 degrees. 25
7. 7. A blade as claimed in any preceding claim, wherein the blade is straight.
8. 8. A saw comprising a blade according to any one of the preceding claims.
9. 9. A saw as claimed in claim 8, configured for use as a hand saw.
10. 10. A blade for a reciprocating saw, substantially as hereinbefore described with HimzifimmvovmWRPonbflDCCVwiZRSé X3369_l doc—2