GB2509305A

GB2509305A - Portable Tool with Dual Blades

Info

Publication number: GB2509305A
Application number: GB201220649A
Authority: GB
Inventors: Marlan Barrett
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-11-16
Filing date: 2012-11-16
Publication date: 2014-07-02
Also published as: GB201220649D0

Abstract

A portable saw or angle grinder has a plurality of blades rotating in a housing in a fixed relationship, such as coaxial about a single axial shaft 10. A single motor may rotate both blades in a single direction, the blades being spaced apart to provide two parallel cuts. The spacing between the blades may be fixed or adjustable. The blades may be sprung or thread mounted on the shaft 10. The shaft 10 may be orthogonal to a drive shaft 13 of a motor 17 allowing a similar design to single blade angle grinders. The shaft and drive shaft may interact by bevelled gearing 11, 12 biased into engagement. The shaft may be removable by means of nuts at distal ends of the shaft to allow maintenance, adjustment or replacement of the blades. Alternatively the blades may be removed from the shaft without dislocation of the shaft. A handle may be provided orthogonal to the housing or on a sliding or articulated mount. The blades may be partially housed in the housing and support bars 16 may help maintain the blades in position in use.

Description

I

A PORTABLE ROTARY BLADE POWER TOOL

Field of the Invention

The present invention relates to a portable rotary blade power tool, more particularly but not exclusively a tool similar to an angle grinder

Background of the Invention

With increasing reliance on mechanisation for ease and efficiency throughout the world in many trades and walks of life rotary blade power tools are common.

Such power tools may include sanders or toothed saws and angle grinders which act to cut or saw with a textured or tipped blade or blades.

Said blade or blades isiare discs with which a leading edge in use is tipped with abrasive robust material in order that said material, such as diamond dust or serrated tungsten or other hard formation metal or alloy, is disposed to provide a culling surface.

Said surface, by virtue of spinning provides an effective blade to cut through a variety of materials from masonery, tiling, brick or metal or plastic piping. In accordance with this many users are required to own such a tool and many cuts are made, even in close proximity when the user is required to cut a section of material for example it can be difficult to ensure that cuts are correctly oriented and or parallel as wielding a tool with a high velocity rotating blade can be difficult to achieve precisely, for example when a cut of a certain length is required above or below another such cut, where cuts are required to be parallel; for example where a section of leaking pipe must be replaced.

Prior Art

Accordingly a member of patent documents have been filed previously in an effort to deal with the same or similar problems, including the following: Curated United States patent US 7 950 318, which discloses a driver for twin cutting device which comprises a first blade, which is non-rotatably arranged on a drive shaft to be related about an axis of rotation in a first direction; a second blade. which is non-rotatably arranged on a drive socket, which encloses the drive shaft to be rotated about the same axis of rotation in a second direction opposite to the first direction, the two blades extending parallel to and close to each other, and a drive motor which is arranged to drive both the drive shaft and the drive socket.

German patent application DE 19 601 086 discloses a device that has a two bladed circular saw with a first circular saw blade which is nearer the sheet material than a second saw blade. The circular saw is coaxial to, rotates with and is mounted on the end of a body and works in conjunction with a machining tool.

French granted patent FR 2 661 636 discloses a twin shaft circular sew machine that has two parallel shafts which can be positionally adjusted in the direction at right angles to their axes. Each shaft is filled with a number of circular blades which are spaced axially according to the thickness of the slabs into which the workpiece is to be cut.

In contrast the present invention provides a simple to maintain easy to use portable power tool suitable for a number of purposes and in a commonly recognised and familiar format.

Summary of the Invention

According to the present invention therefore there is provided a portable rotary blade power tool comprising; at least one motor; a unitary housing; a power source; a control means for activating said at least one motor; a plurality of blades votatable by said motor upon activation by said control means wherein; said plurality of blades rotate in said housing in a fixed relationship.

In preferred embodiments the blades rotate coaxially with a fixed spacing along said axis. In such preferred embodiments variation in spacing may be provided by blades with axially displaced 1st and 2nd surfaces, for example wherein two of said 1st surfaces may be used proximate to increase or decrease spacing and vice versa.

Ideally in some embodiments this spacing may be altered or readjusted, wherein variation of the spacing may be made in use to account for user preference or conditions.

In preferred embodiments however said spacing is substantially fixed by positioning on an axial shaft. Sprung movement may be envisaged on the shaft or each, individual blade wherein said spring may be provided by inclusion of sprung mountings of the shaft, or blade (s). . The preferred embodiments of the tool use a single axial shaft to rotate the blades for simplicity and said shaft is rotated by a gearing, allowing an orthogonal drive shaft to project from a motor in the housing, wherein the motor may be dislocated from the blades and consequently an easier balance of gravity provided for a user allowing the blade to be projecting outermost in common with single blade angle grinders.

Said gearing typically includes teeth on the axial and drive shafts inclined to engage at an acute angle.

Ideally said axial shaft is capable of dislocation or displacement in order that the blades may be replaced or maintained.

In some embodiments the axial shaft may be dislocated and replaced entirely, for example wherein a different spacing is required between blades. In other embodiments the blades may be displaced or detached from the axial shaft after the axial shaft has been dislocated.

The axial shaft therefore ideally includes a release mechanism from the housing wherein said mechanism releases the axial shaft after rotation has stopped. Said mechanism may comprise nuts at distal ends of the axial shaft, after or before the blades.

In preferred embodiments the blades are displaced from the axial shaft without dislocation of the shaft, wherein the mechanism is bipartite and acts at either end of the axial shaft to allow the blades to come off or slide of the axial shaft, For example the blades may be pressed onto the axial shaft by springs and/or a screwthread mechanism which is engaged by the user after maintenance or replacement of blades.

Ideally mechanical engagement allows electrical engagement such that the control menas my activate the motor(s) so as to rotate the blades.

In this way the axial shaft and drive shaft may be maintained in a fixed and stable relationship, less liable to damage in use. In some embodiments said relationship may be further consolidated by support structures or bars wherein said bars provide additional or sole axial strength and ideally allow the axial shaft to rotate freely, for example interacting at a ball bearing or self-lubricating joint.

Wherein the drive shaft interfaces with the axial shaft only at a gearing.

In preferred embodiments such gearing or interface is biased to engagement, wherein for example the drive shaft is biased or urged into the axial shaft to ensure interface. In accordance with this the bars provide structural rigidity to the axial shaft transverse to the axis also.

The axial shaft, gearing interface and support bars therefore in total form a bearing on which both blades rotate. Said bearing may be accessible to the user or wholly self-contained and behind guarding in order to minimise issues in cutting.

In embodiments where the bearing is accessible the bars may be releasable, wherein the gearing interlace is not fixed, in order that the axial shaft and bars may be dislocated after release at or without the blades.

Other parts of the tool may be displaceable so as to aid in use, maintenance, replacement or safety, for example wherein guards or parts of the housing may be included about the blades ot prevent accidental damage, and removed or displaced to inprease cutting area.

In order to assure ease of use and portability ideally the housing is provided with at least one handle to enable the tool to be easily manipulable. Said handles are ideally orthogonally disposed to aid in full manipulation. In some embodiments at least one of said handles or an only handle, may be displaced about and for with reference to the housing for example being provided on a sliding or articulated mounting.

Typically the tool is powered by mains electricity in order to ensure sufficient power is available for at least one motor capable of rotating two blades at sufficient revolutions, although at least one rechargeable may be effective in correct circumstances to increase portability.

In preferred embodiments the motor is controlled by the control menas at a plurality of speed settings, in counter rotational directions. Automatic shut is ideally included in event of power supply spikes, mechanical disconnection in bearings, and/or controllable by the user, to varying levels of resistance.

Some embodiments of the tool may include dust bags, containers or guards. Preferred embodiments of the tool include air intakes and exhaust outlets.

Reference will now be made to the Figures in which:

Brief Description of the Ficiures

Figure 1 shows an isometric view of a preferred embodiment of the inventiOn; Figure 2 shows a side view of the embodiment shown in Figure 1 with a part of the housing removed; Figure 3 shows a view from below of the embodiment shown in Figure 1; Figure 4 shows a view from above of the embodiment show in Figure 1; Figure 5 shows end views of the embodiment shown in Figure 1; Figure 6 shows side views of the embodiment show in Figure 1; Figure 7 shows an isometric view of the embodiment shown in Figure 1 with part of the housing removed.

Detailed Description of the Figures

With reference to the Figures therefore; the preferred embodiment of the tool features two blades 1, 2 which are partially housed in a housing 3. The housing 3 is constructed in robust plastic or metal parts and includes a handle at a side to aid application of pressure and a handle rearmost in use to aid guidance as well as a handle carrier 5 for carrying the tool.

The housing 3 further includes a centrally mounted air intake which leads to an air iniake fan ??5 (Fig2) 7 and central top axial shaft securement and cover 8. and dismountable side guards 9.

Turning now to Figure 2, the blades 1 and 2 are mounted on an axial shaft 10, which axial shaft 10 with bevelled gearing 11 on the axial shaft 10 cooperating bevelled gearing 12 on the drive shaft 13. The drive shaft 13 leads to a rotor 14 and motor 17.

Support bars 16 help to maintain the blades 12 in position in use.

With reference to Figure 3 ideally the handle 4 is detachable by a screwthread, and a transverse support 18 is threaded through the support bars 16, which transverse support may be removed to allow movement of the bearing or blade assembly, comprising blades 1 2 support bars 16, axial shaft 10. Blade 2 may in preferred embodiments be removed by loosening of nut 19.