WO2010010474A1

WO2010010474A1 - A rotary power driven saw

Info

Publication number: WO2010010474A1
Application number: PCT/IB2009/052845
Authority: WO
Inventors: Trevor Charles Crozier
Original assignee: Trevor Charles Crozier
Priority date: 2008-07-21
Filing date: 2009-06-30
Publication date: 2010-01-28
Also published as: WO2010010474A9

Abstract

A rotary power driven saw 10 includes a main body 12 which carries displaceable components including a drive motor having a rotary power output shaft 24, a saw blade 16 connected to a piston-body 18 that is linearly displaceable within a guide formation along a line parallel to the axis of the rotary power output shaft of the drive motor and power transmission means for transmitting the rotary output power from the drive motor to the piston-body for displacing the piston-body 18 in a reciprocating motion, the power transmission means comprising a swash plate-type arrangement 26 which mechanically connects the power output shaft of the drive motor with the piston-body.

Description

A ROTARY POWER DRIVEN SAW

FIELD OF THE INVENTION

This invention relates to a rotary power driven saw.

The invention relates particularly to a saw that has a saw blade displaceable in a reciprocating motion by the rotary output of an electric or pneumatic drive motor, such a saw being referred to herein as a rotary power driven saw.

BACKGROUND TO THE INVENTION

A rotary power driven saw having a saw blade that is displaceable by an electric motor is known, the saw blade being mechanically linked to the rotary output of the electric motor by a power transmission means in the form of a crank arrangement which transforms the rotary motion of the motor output into reciprocating motion of the saw blade. Insofar as the general configuration of such a rotary power driven saw is well known, this is not described in further detail herein.

It is known that the above rotary power driven saw, in use, transmits substantial vibration to the user of the saw, which can have detrimental effects. As such, it is an object of this invention to provide an improved rotary power driven saw in respect of which the above problem is at least ameliorated.

SUMMARY OF THE INVENTION

According to the invention there is provided a rotary power driven saw, which includes a body carrying, in its in-use configuration,

a drive motor having a rotary power output shaft;

a saw blade connected to a piston-body that is linearly displaceable within a guide formation along a line parallel to the axis of the rotary power output shaft of the drive motor; and

a power transmission means for transmitting the rotary output power from the drive motor to the piston-body for displacing the piston body in a reciprocating motion, the power transmission means comprising a swash plate-type arrangement which mechanically connects the power output shaft of the drive motor with the piston- body.

The swash plate-type arrangement may include a ball bearing that has its inner race secured on a segment of an extension body that defines an axis angularly offset with respect to the axis of the power output shaft of the drive motor and that is mechanically connected thereto, the outer race of the ball bearing having a connector arm being displaceable relative within a bore therefore, defined within a cylindrical body rotatably located within the piston-body for rotation about an axis perpendicular to the axis of rotation of the power output shaft.

The drive motor may be a pneumatic motor and, as such, the rotary power driven saw may include a passage arrangement including connector means for connecting the motor to a compressed air supply for driving the motor. The pneumatic motor may be associated with an activating means for activating operation of the motor, i.e. for initiating and controlling the feed of compressed air to the motor.

Alternatively, the drive motor may be an electric motor and, as such, the saw may include a connector arrangement for electrically connecting an electric power supply to the motor. Once again, an activating means may be provided for activating the operation of the electric motor, i.e. to enable and control the power supply to the electric motor.

The swash plate-type arrangement forming the power transmission means of the rotary power driven saw of the invention clearly can be configured in various different configurations while utilizing the swash plate principles for transmitting power from a rotary power output to a body displaceable in a reciprocating motion. It is particularly envisaged in this regard that the defined configuration of the swash plate-type arrangement including the ball bearing connected, via a connector arm and a rotatably located cylindrical body, to the piston body, will be effective in relation to reducing vibrations associated with the use of the power driven saw and thus at least ameliorating the known physical problems that users of known rotary power driven saws are exposed to when using these saws over extended time periods. The swash plate-type arrangement also may be operatively linked with a secondary piston-body that is displaceable in a reciprocating motion and that is located with respect to the swash plate-type arrangement diametrically opposite the piston-body that is connected to the saw blade.

BRIEF DESCRIPTION OF THE DRAWINGS

A rotary power driven saw, in accordance with the invention, is described hereafter with reference to an example of a saw, which is illustrated in the accompanying diagrammatic drawings. In the drawings: Figure 1 shows a three-dimensional view of a rotary power driven saw, in accordance with the invention, in a first operative configuration thereof;

Figures 2 shows a cross-sectional side view of the rotary power driven saw of Figure 1 , in the same first operative configuration thereof;

Figure 3 shows a side view of the rotary power driven saw of

Figure 1 , in a second operative configuration thereof; and

Figure 4 shows a side view of the rotary power driven saw of

Figure 1 , in a third operative configuration thereof.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

Referring to the drawings, which show a rotary power driven saw, in accordance with the invention, in relation to all the drawings various components and parts and segments of components and parts are not shown, particularly to facilitate the description of the rotary power driven saw and an explanation of the operation thereof. The exact configuration of the rotary power driven saw as shown can, however, be easily envisaged and can also be varied in various different respects while providing a saw which still includes all the essential principles of the rotary power driven saw of the invention.

The rotary power driven saw, in accordance with the invention and as shown in the drawings, is designated generally by the reference numeral 10. The saw 10 includes a main body 12 which carries the displaceable components and parts of the saw 10 as described hereafter, the body including a handle 14 that permits the manual manipulation of the saw, in use.

The saw 10 also includes a saw blade 16 which is connected to a piston-body 18, the piston-body 18 together with the saw blade 16 being linearly displaceable in a reciprocating motion within a guide formation 20 defined by the body 12. The saw blade 16 is separable from the piston-body 18 to permit replacement thereof when required.

The piston-body 18 is displaced in a reciprocating motion by the operation of a pneumatic motor (not clearly shown) which is securely located within the body 12 in the region 22 thereof, the motor 22 having a rotary power output shaft 24 which is connected to the piston body 18 by a power transmission means in the form of a swash plate-type arrangement, designated generally by the numeral 26. The pneumatic motor can be operatively connected to a compressed air supply via a suitable connector arrangement (not shown), an activating button 28 being operable for controlling the operation of a valve that can control the supply of compressed air to the pneumatic motor for the operation of the saw 10.

The swash plate-type arrangement 26 includes an extension body in the form of an adaptor shaft 30 that is connected to the shaft 24 to be rotatable therewith, the adaptor shaft 30 including a shaft segment 32 that defines an axis of rotation that is axially offset with respect to the axis of rotation of the adaptor shaft 30 and, as such, the rotary output shaft 24 of the pneumatic motor. The shaft segment 32 has a ball bearing arrangement 34 securely located thereon via the inner race of the ball bearing arrangement, the outer race of the ball bearing arrangement having a connector arm 36 extending therefrom as shown. The free end of the connector arm 36 is slidably located within a bore defined therefor within a cylindrical body 38, the cylindrical body 38 being rotatably located within a complementary formation defined therefore by the piston-body 18, the cylindrical body particularly being rotatable about an axis that is perpendicular to the axis of rotation of the rotary output shaft 24 of the pneumatic motor. The connector arm 36 thus effectively connects the swash-plate type arrangement 26 to the piston- body 18, rotation of the rotation of the rotary output shaft 24 thus providing for linear reciprocating displacement of the piston-body 18 via the swash plate-type arrangement 26 (this is explained in more detail hereafter).

The saw 10 includes also a secondary piston-body 40 that is linearly displaceable in a reciprocating motion within a secondary guide formation 42 defined therefore by the body 12, the piston-body 40 being disposed diametrically opposite the piston-body 18, with respect to the swash plate-type arrangement 26, and also being effectively connected to the rotary output shaft 24 by a connector arm 44 that is slidably located within a bore defined therefore within a cylinder body 46 that is located for rotation within the piston-body 40, as is clearly illustrated.

Figures 1 and 2 of the drawings illustrate the saw blade 16 in its "retracted" limit position, rotation of the rotary output shaft 24 through 90° providing for the position of the saw blade 16 as shown in Figure 3 of the drawings, whereas rotation of the rotary blade output shaft 24 through 180° provides for the position of the saw blade 16 in its fully "extended" limited position, providing for one complete stroke of the blade 16. The reverse stroke of the saw blade 16 clearly will occur in response to rotation of the power output shaft 24 through a further 180 °, high speed rotation of the rotary output shaft 24 thus providing for high speed reciprocating displacement of the saw blade 16 in order to permit it to fulfil its required sawing function. It is submitted in this regard that the use of the saw 10 will be associated with a significantly reduced transmission of vibrations to the user of the saw, particularly when compared with the use of equivalent type saws that provide for the rotary power output of a motor to be transmitted to the saw blade thereof via a crank arrangement. In particular, it is submitted that the swash plate-type arrangement whereby the rotary power output of the motor of the saw is transmitted to the saw blade is an arrangement that provides for the "smooth" displacement of the saw blade which will, in use, be associated with reduced vibrations. The exact configuration and the mechanical construction of the rotary power driven saw 10 as described clearly can be varied in various different respects, while still incorporating the general principles of construction and operation as described above. The invention extends also to all such different configurations of the saw which can be envisaged. The rotary power driven saw of the invention clearly can be associated also with an electric motor that can serve to drive the saw blade thereof.

Claims

CLAIMS:

1. A rotary power driven saw (10), which includes a body (12) carrying, in its in-use configuration,

a drive motor having a rotary power output shaft;

a saw blade (16) connected to a piston-body (18) that is linearly displaceable within a guide formation (20) along a line parallel to the axis of the rotary power output shaft of the drive motor; and

a power transmission means for transmitting the rotary output power from the drive motor to the piston-body in a reciprocating motion, the power transmission means comprising a swash plate-type arrangement (26) which mechanically connects the power output shaft (24) of the drive motor with the piston-body (18).

2. A rotary power driven saw as claimed in claim 1 , wherein the swash plate- type arrangement (26) includes a ball bearing that has its inner race secured on a segment of an extension body that defines an axis angularly offset with respect to the axis of the power output shaft (24) of the drive motor and that is mechanically connected thereto, the outer race of the ball bearing having a connector arm (36) secured thereto and extending therefrom with the free end of the connector arm being displaceably received within a bore therefore, defined within a cylindrical body (38) rotatably located within the piston-body for rotation about an axis perpendicular to the axis of rotation of the power output shaft.

3. A rotary power driven saw as claimed in any one of the preceding claims, wherein the drive motor is a pneumatic motor and the rotary driven saw includes a passage arrangement including connector means for connecting the motor to a compressed air supply for driving the motor.

4. A rotary power driven saw as claimed in claim 3, wherein the pneumatic motor is associated with an activating means for activating operation of the motor.

5. A rotary power driven saw as claimed in any one of claims 1 and 2, wherein the drive motor is an electric motor and wherein the saw includes a connector arrangement for electrically connecting an electric power supply to the motor.

6. A rotary power driven saw as claimed in any one of the preceding claims, wherein the swash plate-type arrangement forming the power transmission means of the rotary power driven saw is configurable to utilize the swash plate principles for transmitting power from a rotary power output to a body displaceable in a reciprocating motion.

7. A rotary power driven saw as claimed in any one of the preceding claims, wherein the swash plate-type arrangement is operatively linked with a secondary piston-body (40) that is displaceable in a reciprocating motion and that is located with respect to the swash plate-type arrangement (26) diametrically opposite the piston-body that is connected to the saw blade.