GB2287218A

GB2287218A - A band saw

Info

Publication number: GB2287218A
Application number: GB9403998A
Authority: GB
Inventors: Mirco Rossetti
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 1994-03-02
Filing date: 1994-03-02
Publication date: 1995-09-13
Also published as: GB9403998D0

Abstract

A band saw including a upper blade guide 1, the upper blade guide 1 comprising a post 3 slidably received in a channel 5 of the bad saw and carrying a guide 19 for supporting a blade 21 and a locking device 9 for locking the post 3 and hence the guide 19 in a desired position relative to the channel 5, wherein the post 3 is carried by the locking device 9 such that positioning of the locking device 9 positions the guide 19 prior to locking of the locking device 9. Further, the locking device may project through the post and, when released, be free to slide along slits in the channel the locking device when locked squeezing opposed sides of the channel onto the post to retain the post in position. As a result, a more secure and improved positioning of the post, and hence the guide, can be readily achieved. <IMAGE>

Description

A BAND SAW This invention relates to band saws, and in particular to an improved upper blade guide for a band saw.

Band saws for cutting workpieces comprise a wheel mounted above a work surface and a wheel below the work surface about which a continuous saw blade passes. One side of the blade loop between the wheels is designated the cutting side and is where workpieces are cut by the band saw.

It is desirable to have saw blade guides above and below the work surface to ensure that the blade is correctly aligned as it passes through a workpiece mounted on the work surface. As a result, most band saws have an upper and a lower blade guide. The invention of this application relates primarily to the upper blade guide of a band saw.

To improve control of the saw blade, it is preferable for the upper blade guide to be movable so that it can be positioned as close to the surface of a workpiece as possible. As a result, it is known to have a post slidably mounted relative to the fixed body of the band saw, the post carrying means for guiding the saw blade. A bolt passes through the post and through a hole in the fixed body of the band saw for engagement by a threaded nut or knob which, when tightened, grips the post to the fixed body. The actual position of the post can be varied by releasing the nut or knob and allowing the post to slide up and down relative to the bolt by means of slits formed in the post.

Although the prior art arrangement described above is satisfactory, it is necessary for a user to use one hand to release the knob and a second hand to control the position of the post relative to the fixed frame of the band saw. This is because, if the knob is simply released, the post will immediately drop until the bolt reaches the end of the slits in the post.

In the light of the foregoing, the present invention aims to improve upon the prior art arrangement. Accordingly, the present invention provides a band saw including an upper blade guide, the upper blade guide comprising a post slidably received in a channel of the band saw and carrying a guide for supporting a blade and a locking device for locking the post and hence the guide in a desired position relative to the channel, wherein the post is carried by the locking device such that positioning of the locking device positions the guide prior to locking of the locking device.

By having the post carried by the locking device, a user may simply grip the locking device both to control the locking device and to position the post in relation to the fixed body of the band saw using one hand.

Simple control of the position of the guide can therefore be achieved.

According to another aspect of the present invention, there is provided a band saw including an upper blade guide, the upper blade guide comprising a post slidably received in a channel of the band saw and carrying a guide for supporting a blade and a locking device for locking the post and hence the guide in a desired position relative to the channel, wherein the locking device projects through the post and, when released, is free to slide along a pair of slits in opposite sides of the channel, the locking device when locked squeezing the opposite sides of the channel onto the post to retain the post in position.

By squeezing opposing sides of the channel onto the post, more even, reliable and accurate positioning of the post (and hence the guide) can be achieved.

Preferably the post and channel are substantially rectangular in cross-section.

The locking device is preferably released by means of an exposed knob, which can be readily gripped by a user of the band saw. If an exposed knob is used, the locking device preferably comprises a threaded rod or bolt upon which the exposed knob is threadedly received.

The locking device preferably includes bearing plates for abutting opposite outside surfaces of the channel during locking of the locking device. By including bearing plates of significant area, a more even and reliable gripping of the post can be achieved upon locking of the locking device. With this in mind, as will be appreciated, the channel is slightly resilient and can therefore be deformed to grip the post when the locking device is locked.

Preferably the guide comprises a bearing surface and a pair of opposed guide rollers. The opposed guide rollers are preferably arranged to face the sides of a saw blade to prevent the blade from twisting during cutting of a workpiece.

The bearing surface is preferably provided by a rotating roller or wheel which abuts the rear of the saw blade.

Although the channel could in theory be formed of any suitable material, it is preferably formed from galvanised steel plate which is slightly resilient, as mentioned above.

A specific embodiment of the present invention is now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional plan view of a band saw upper blade guide according to the present invention; and Figure 2 is a schematic sectional side view, with part of the saw blade cut away, in the direction A-A of Figure 1.

With reference to the drawings, an upper blade guide 1 for a band saw includes a post 3 slidably received within a channel 5 forming part of a fixed frame 7 of a band saw. The post 3 and channel 5 are both substantially rectangular in cross-section and the post 3 is received with a relatively close fit in the channel 5, but with sufficient freedom to be moveable therealong when a locking device 9 is released.

The locking device 9 comprises a threaded bolt 11 passing through holes 13 in opposite sides ofthe post 3 and slits 15 in corresponding opposite sides of the channel 5. An exposed knob 17 is threadedly received on the threaded bolt 11 to clamp the channel 5 onto the post 3 via a washer 18. As a result, when the locking device 9 is released by unscrewing the knob 17, the post 3 can be moved up and down due to the slits 15 in the channel 5 by a user holding the knob 17. Further, when the post 3 is in a desired position, the knob 17 can simply be tightened to force the walls of the channel 5 into contact with the post 3 to grip and lock the post 3 relative to the channel 5.

Although the channel 5 can be made of any suitable material which allows it to be compressed onto the post 3 when the locking device 9 is locked, the channel 5 is preferably made from galvanised steel plate.

Towards the bottom of the post 3, a guide 19 is mounted for supporting and directing a saw blade 21 of the band saw. More particulary, the guide 19 comprises a support 23 carrying a bearing roller 25 against which the rear of the saw blade 21 bears during cutting.

Further, the support 23 also carries a pair of opposed side rollers 27 which are positioned to prevent the saw blade 21 from twisting during cutting.

It will of course be understood that the present invention has been described above purely by way of example, and that modifications of detail can be made within the scope of the invention.

Claims

1. A band saw including an upper blade guide, the upper blade guide comprising a post slidably received in a channel of the band saw and carrying a guide for supporting a blade and a locking device for locking the post and hence the guide in a desired position relative to the channel, wherein the post is carried by the locking device such that positioning of the locking device positions the guide prior to locking of the locking device.

2. A band saw including an upper blade guide, the upper blade guide comprising a post slidably received in a channel of the band saw and carrying a guide for supporting a blade and a locking device for locking the post and hence the guide in a desired position relative to the channel, wherein the locking device projects through the post and, when released, is free to slide along slits in the channel, the locking device when locked squeezing the opposed sides of the channel onto the post to retain the post in position.

3. A band saw as claimed in claim 1 and as claimed in claim 2.

4. A band saw as claimed in any preceding claim, wherein the post and the channel are substantially rectangular in cross-section.

5. A band saw as claimed in any preceding claim, wherein the locking device is released by means of an exposed knob.

6. A band saw as claimed in claim 5, wherein the locking device comprises a threaded rod upon which the exposed knob is threadedly received.

7. A band saw as claimed in any preceding claim, wherein the locking device includes bearing plates for abutting opposite outside surfaces of the channel during locking of the locking device.

8. A band saw as claimed in any preceding claim, wherein the guide comprises a bearing surface and a pair of opposed guide rollers.

9. A band saw saw as claimed in claim 8, wherein the bearing surface is provided by a rotating roller.

10. A band saw as claimed in any preceding claim, wherein the channel is formed from galvanised steel plate.

11. A band saw including an upper blade guide, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.