GB2183542A - Blade guide for mitre box - Google Patents

Abstract

A blade guide device, for use on a mitre box to guide the blade of the saw and to protect the surfaces bounding the slots of the box, has two guide members bounding the slot, one such guide member having hemispherical projecting stops 4 urged by spring-loading 5 across the slot, and the other such guide member having circular openings 15 into which the stops can enter, the introduction of the saw blade into the slot causing the stops to be moved back against their loading so that the blade is held and guided between the stops and the other guide member. <IMAGE>

Description

SPECIFICATION Blade guide device for mitre box This invention relates to a blade guide devicefora mitre box.

hisintended to perm it the protection of the slots guiding the saw for cutting off workpieces at a predetermined angle, whilst giving a greater pre'vision to the cut, above all for small workpieces such as mouldings, cornices, framing barsorthe like It is known to use blade guides for mitre boxes of large dimensions, such as those employed in construction work. Thus, whilst there have been employed balls with loading springs, such devices cannot be employed in mitre boxes of small dimensions, the walls of which are narrow.

The device of the invention eliminates these inconveniences and permits, by prefabrication,to obtain a blade guide constituted by a wall comprising a semi-spherical guiding element integrated with its loading spri ng, and a wal I provided with circular openings, assuring the points of connection separating underthe passage of the saw, which notonlyavoidswearoftheslotbutgives the path of the saw a very great precision for workpieces or assemblies requiring a perfect regularity.

It is constituted by the combination of a metallic member comprising a cutout portion bounding a hemisphere, the attachment of which to the bearing surface constitutes a flat elastic spring, and a counterpart provided with openings of diameter corresponding to that of the hemispheres; these two members each have lateral faces bent at 900 in such a manner as to embrace the surface of the slots of the mitre box over all of their height and lateral walls.

In the accompanying drawings, given byway of non-limiting example, of one of the forms of construction ofthe invention: Figures land 2 show in front elevation and in side elevation the formation of the semi-spherical stops and oftheirspring; Figures 3 and 4 show in similar mannerthe formation ofthe receiving openings; Figure5is a view in transverse section ofthe whole ofthe device; Figures 6 and 7 are views in perspective and to different scales of the mitre box with its blade guide elements.

The blade guide, figures 1,2,3, 4and 5, is constituted on the one hand by a metal fitting 1 bent up in the shape of a "U ", with rebated flanges 2, 3.

It comprises on its front face a series of cutouts and shapings determining a convex semi-spherical sector 4, and a flexible attachment portion 5, forming both a spring and a support, fast with the bearing surface and assuring elasticity when flat.

This mounting is placed in an applying frame 6 which is placed over the surface ofthe slots 7,8,9,10 and 11, of small dimensions (figures 6 and 7).

The counterpart is formed, figures 3, 4 and 5, by a metal profiled member comprising rebates 12,13 including circular perforations 14, 15 having the same diameter as the movable semi-spherical stops 4 made in relief by stamping.

When these mountings are placed along the slots7 etc., the spherical sectors 4 enter into the openings 15 etc.

The saw, during its passage, must separate them over all of the height of the blade, which will thus be guided during the cutting of the workpiece.

The saw cut will thus be of a perfect regularity and will have the exact width of the blade without enlargement or deviation.

This precision of cut will be increased in time because the surface ofthe slots ofthe mitre box will no longer wear, and the fittings themselves on their faces 16,17will be protected.

This device, more particularly intended for mitre boxes of small dimensionsforworksofartandof great precision, can be used for mitre boxes employed for larger work of assembly ofvarious pieces, without having to increase the thickness of the walls of the box.

1. Blade guide device for a mitre box, serving to permit the protection of the slots guiding the blade of the saw for the cutting off of workpieces at a predetermined anglewhilstgiving a greater precision ofthe cut, above all for small workpieces of art and of precision, it being specified that this blade guide neither notches nor diminishes the surfaces of the slot ofthe mitre box, which remain intact by the obtaining of elasticity in the flat, characterised by the combination of a guide element covering the height ofthe slots ofthe mitre box with protecting and centring rebates and comprising cutouts and formations providing a semi-spherical sector, ferrules, and a flexible attachment forming a spring coupling the movable element to its support, and a profiled portion with lateral rebatings bent up at a right angle and with a front surface provided with circularperforationsofthesamediameterasthe semi-spherical movable stops.

2. Device, according to claim 1, wherein said blade guides protect the slots of the mitre box, fitting in symmetrically on the surfaces ofthe openings in such a mannerthateach semi-spherical stop corresponds to an opening and enters slightly into said opening.

3. Device, according to claim 1 or claim 2, wherein the cutout member with lateral rebatements is placed in a corresponding profiled mounting in orderto permit bending ofthe spring and ofthe semi-spherical stop in order to assure the exact passage of the blade ofthe saw stabilised overthe whole of its height during the precision cutting ofthe workpiece to be cut off.

4. Device, according to any one of the preceding claims, wherein the combination of the cutout member and the support mounting avoids any notching and wear of the surfaces of the slot on which it is mounted.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Blade guide device for mitre box This invention relates to a blade guide devicefora mitre box. hisintended to perm it the protection of the slots guiding the saw for cutting off workpieces at a predetermined angle, whilst giving a greater pre'vision to the cut, above all for small workpieces such as mouldings, cornices, framing barsorthe like It is known to use blade guides for mitre boxes of large dimensions, such as those employed in construction work. Thus, whilst there have been employed balls with loading springs, such devices cannot be employed in mitre boxes of small dimensions, the walls of which are narrow. The device of the invention eliminates these inconveniences and permits, by prefabrication,to obtain a blade guide constituted by a wall comprising a semi-spherical guiding element integrated with its loading spri ng, and a wal I provided with circular openings, assuring the points of connection separating underthe passage of the saw, which notonlyavoidswearoftheslotbutgives the path of the saw a very great precision for workpieces or assemblies requiring a perfect regularity. It is constituted by the combination of a metallic member comprising a cutout portion bounding a hemisphere, the attachment of which to the bearing surface constitutes a flat elastic spring, and a counterpart provided with openings of diameter corresponding to that of the hemispheres; these two members each have lateral faces bent at 900 in such a manner as to embrace the surface of the slots of the mitre box over all of their height and lateral walls. In the accompanying drawings, given byway of non-limiting example, of one of the forms of construction ofthe invention: Figures land 2 show in front elevation and in side elevation the formation of the semi-spherical stops and oftheirspring; Figures 3 and 4 show in similar mannerthe formation ofthe receiving openings; Figure5is a view in transverse section ofthe whole ofthe device; Figures 6 and 7 are views in perspective and to different scales of the mitre box with its blade guide elements. The blade guide, figures 1,2,3, 4and 5, is constituted on the one hand by a metal fitting 1 bent up in the shape of a "U ", with rebated flanges 2, 3. It comprises on its front face a series of cutouts and shapings determining a convex semi-spherical sector 4, and a flexible attachment portion 5, forming both a spring and a support, fast with the bearing surface and assuring elasticity when flat. This mounting is placed in an applying frame 6 which is placed over the surface ofthe slots 7,8,9,10 and 11, of small dimensions (figures 6 and 7). The counterpart is formed, figures 3, 4 and 5, by a metal profiled member comprising rebates 12,13 including circular perforations 14, 15 having the same diameter as the movable semi-spherical stops 4 made in relief by stamping. When these mountings are placed along the slots7 etc., the spherical sectors 4 enter into the openings 15 etc. The saw, during its passage, must separate them over all of the height of the blade, which will thus be guided during the cutting of the workpiece. The saw cut will thus be of a perfect regularity and will have the exact width of the blade without enlargement or deviation. This precision of cut will be increased in time because the surface ofthe slots ofthe mitre box will no longer wear, and the fittings themselves on their faces 16,17will be protected. This device, more particularly intended for mitre boxes of small dimensionsforworksofartandof great precision, can be used for mitre boxes employed for larger work of assembly ofvarious pieces, without having to increase the thickness of the walls of the box. CLAIMS

1. Blade guide device for a mitre box, serving to permit the protection of the slots guiding the blade of the saw for the cutting off of workpieces at a predetermined anglewhilstgiving a greater precision ofthe cut, above all for small workpieces of art and of precision, it being specified that this blade guide neither notches nor diminishes the surfaces of the slot ofthe mitre box, which remain intact by the obtaining of elasticity in the flat, characterised by the combination of a guide element covering the height ofthe slots ofthe mitre box with protecting and centring rebates and comprising cutouts and formations providing a semi-spherical sector, ferrules, and a flexible attachment forming a spring coupling the movable element to its support, and a profiled portion with lateral rebatings bent up at a right angle and with a front surface provided with circularperforationsofthesamediameterasthe semi-spherical movable stops.

2. Device, according to claim 1, wherein said blade guides protect the slots of the mitre box, fitting in symmetrically on the surfaces ofthe openings in such a mannerthateach semi-spherical stop corresponds to an opening and enters slightly into said opening.

3. Device, according to claim 1 or claim 2, wherein the cutout member with lateral rebatements is placed in a corresponding profiled mounting in orderto permit bending ofthe spring and ofthe semi-spherical stop in order to assure the exact passage of the blade ofthe saw stabilised overthe whole of its height during the precision cutting ofthe workpiece to be cut off.

4. Device, according to any one of the preceding claims, wherein the combination of the cutout member and the support mounting avoids any notching and wear of the surfaces of the slot on which it is mounted.

5. Blade guide device for a mitre box substantially as described herein with reference to the figures ofthe accompanying drawing.