GB2533916A

GB2533916A - Saw

Info

Publication number: GB2533916A
Application number: GB1421458.9A
Authority: GB
Inventors: Philip Bradshaw David
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-12-03
Filing date: 2014-12-03
Publication date: 2016-07-13
Also published as: GB201421458D0

Abstract

A handle 14 or grip for a handheld saw 10 has at least one air inlet 26, and air outlet 28 arranged immediately adjacent to the blade 12 and may point forward and down in relation to the saw blade. An electric blower is arranged to draw air in through the air intakes 26 and exhaust it through the outlets 28. The blower may comprise an electric motor and fan head 22, 24 and may be powered by an electric battery 32 mounted in the handle. There may be an electronic controller 34 which may provide one or more of the functions of fan speed control, a timer, or a low-battery alert. There may also be a clinometers and device for indicating saw orientation to the user, which may be a visual indicator. Furthermore, there may be a light emitter such as an LED 38 mounted on the handle. Also disclosed is a handheld saw with at least one air inlet and air outlet and an electric blower arranged to draw air in through the air inlets and exhaust the air through the air outlets positioned to direct the air onto a work piece to disperse saw dust.

Description

SAW

The present invention relates to a handheld saw, and in particular to a handheld saw provided with an arrangement for automatically dispersing saw dust.

The term "handheld saw" as used herein refers to the type of tool which has a toothed blade and a handle by means of which the toothed blade is moved back and forth to form a cut. It is to be understood to include, without limitation, backless saws, hand saws, pad saws, back saws, tenon saws, dovetail and gentleman's saws, hacksaws, coping saws and Japanese saws. It includes but is not limited to saws for cutting both timber and metal. It does not encompass any type of saw whose cutting action is mechanically powered, such as circular saws or power jigsaws.

Handheld saws have been known for thousands of years and are used across the world. Part of the skill of using a handheld saw lies in making the cut in the required place. Typically where any degree of accuracy is required, lines are marked on the visible faces of a work piece representing the plane in which the saw cut is to be made. In the case of a crosscut through a square section work piece, for example, a square is conventionally used to mark a line around all four faces of the work piece and the craftsman positions and aligns the saw so that as it cuts the kerf it forms lies on or immediately adjacent the marked line.

Handheld saws produce saw dust as they cut. Note in this connection that whereas sawdust is often thought of being from cutting wood, no such limitation is implied here -the term "saw dust" is used to refer to the dust created by the saw's cutting action, whatever the material of the work piece may be. Saw dust tends at least in part to be deposited on the visible faces of the work piece, especially during the saw's forward stroke, and can consequently obscure the marked line. It is a common practice for the craftsman to pause periodically during sawing, remove the saw from the kerf and blow or brush away the dust. This is time consuming and can be a health hazard. Accumulation of saw dust can also clog the blade when cutting certain materials such as resinous timber.

Japanese patent application 20070097835, published under no. JP2008213447A, discloses an automatic blower having a cylinder with a narrowed outlet nozzle at one end and an internal piston, so that movement of the piston toward the nozzle causes air to be expelled to disperse saw dust. The cylinder is provided with a horseshoe-shaped clip for attachment to the round handle of a Japanese saw. It appears that the necessary reciprocating action of the piston is expected to be created merely due to the saw's own reciprocal motion. One might question whether a sufficient volume of air could be displaced to have the required effect, and the convenience of having the arrangement clipped to the saw.

According to the present invention, there is a handle for a handheld saw comprising at least one air inlet, at least one air outlet, and an electric blower arranged to draw air into the handle through the inlet and to exhaust it through the outlet, the outlet being positioned and oriented to direct the exhausted air onto a work piece while a saw incorporating the handle is being used, thereby to disperse saw dust from the work piece.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawing, Figure 1, which is a somewhat schematic representation of a section through a saw embodying the present invention, the section being in the plane of the saw blade.

The handheld saw 10 depicted in Figure 1 is a handsaw -that is, as the skilled person is aware, a form of backless saw with a relatively deep but thin metal blade 12 and a handle 14 shaped to be gripped comfortably in one hand and having a roughly "D" shaped cutout 16 through which the user's middle, ring and little fingers pass, the index finger normally being placed along the handle to help guide the saw. The blade's edge 18 carries cutting teeth, although these are not represented in the drawing.

A root portion of the blade 12 is received in the handle 14 and is secured by means of screws 20, of which there are three in the present embodiment although one, two or more than three screws could be used in other embodiments. The screws 20 pass through the blade 12 and are threadedly received in a portion of the handle 14 so that they can be tightened to prevent play between the blade 12 and the handle 14.

Removing the screws 20 allows the blade 12 to be slid out of the handle and replaced. A range of different interchangeable blades may be provided, e.g. with teeth adapted to cutting different materials, or with blades of different depths lengths and shapes, all of them usable with the same handle 14.

In other embodiments the saw's blade and handle may be permanently attached to one another. The saw may for example be of the type intended to be replaced once blunted, or may be intended to be periodically re-sharpened.

Within the handle 14 is an electric blower which may take a range of different forms but which in the present embodiment comprises an electric fan having a motor 22 and fan blades schematically represented at 24. The electric fan 22, 24 draws air into the handle 14 through inlets 26 and propels it via ducting within the handle 14 (not shown) through outlets 28. In the present embodiment the outlets 28 are arranged immediately adjacent the blade 12, directed in a forward and downward direction with respect to the blade. There is a bank of four outlets 28 in the present embodiment but a different number may be provided.

The fan motor 22 is switched on and off by means of a switch 30 in an upper part of the handle 14 and is driven from a battery 32 received inside the handle 14. To enable replacement of the battery the handle 14 incorporates an openable battery hatch 33.

An electronic controller 34 also housed in the handle 14 can provide several functions including fan speed control, a timer to switch off the fan after a certain interval and prevent wastage of battery life, and a low battery alert signal, e.g. an audio signal.

According to the present embodiment, the electronic controller also incorporates a clinometer enabling it to determine the angle the saw makes to the vertical in at least one plane. An indication is provided to the user of whether the saw is correctly oriented. In the present embodiment this is a visual signal, given by means of an LED indicator light 36 whose colour changes, e.g. between red and green, to indicate when the saw's angle is correct.

A light is provided to illuminate the work piece in the vicinity of the saw kerf, assisting the user in following a line marked upon the work piece. This light takes the form of an LED 38 in the illustrated example, and is directed forwardly and downwardly with respect to the blade 12, to direct it towards the work piece.

In use, a constant flow of air is provided through the outlets 28. This has the effect of dispersing saw dust that would otherwise settle on the work piece being cut, thus ensuring that the work piece -and particularly any guide line marked on it -is not obscured.

Claims

CLAIMS1. A handle for a handheld saw comprising at least one air inlet, at least one air outlet, and an electric blower arranged to draw air into the handle through the inlet and to exhaust it through the outlet, the outlet being positioned and oriented to direct the exhausted air onto a work piece while a saw incorporating the handle is being used, thereby to disperse saw dust from the work piece.
2. A handle for a handheld saw as claimed in claim 1 in which the electric blower comprises an electric motor and a fan head.
3. A handle for a handheld saw as claimed in claim 1 or claim 2 in which the handle is adapted to receive and mount an electric battery for driving the electric blower.
4. A handle for a handheld saw as claimed in any of claims 1 to 3 in which the outlet is arranged to exhaust air forwardly and downwardly with respect to the saw's blade.
5. A handle for a handheld saw as claimed in claim 4 comprising multiple similarly oriented outlets.
6. A handle for a handheld saw as claimed in any preceding claim further comprising an electronic controller.
7. A handle for a handheld saw as claimed in any preceding claim further comprising a clinometer and a device for indicating to the user whether the saw is correctly oriented.
8. A handle as claimed in claim 7 in which the said device comprises a visual indicator.
9. A handle as claimed in claim 7 in which the said device comprises a light emitter.10. A handle as claimed in any preceding claim further comprising an electronic controller providing one or more of the following functions: fan speed control; a timer; a low battery alert signal.
10. A handheld saw comprising a handle as claimed in any preceding claim and a saw blade attached to the handle.
11. A handheld saw comprising at least one air inlet, at least one air outlet, and an electric blower arranged to draw air into the handle through the inlet and to exhaust it through the outlet, the outlet being positioned and oriented to direct the exhausted air onto a work piece while a saw incorporating the handle is being used, thereby to disperse saw dust from the work piece.
12. A handle for a handheld saw substantially as herein described with reference to, and as illustrated in, the accompanying drawing.
13. A handheld saw substantially as herein described with reference to, and as illustrated in, the accompanying drawing.