GB2196571A

GB2196571A - Router for removing mortar from brickwork

Info

Publication number: GB2196571A
Application number: GB08625299A
Authority: GB
Inventors: Robert Henry Williams
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-10-22
Filing date: 1986-10-22
Publication date: 1988-05-05
Anticipated expiration: 2006-10-22
Also published as: GB2196571B; GB8625299D0

Abstract

A router comprises a wall- engaging sole plate (46) which is pivotally attached to, and inclined with respect to, a tubular housing (12) by means of a rod (34), upon which the housing is slidably mounted. A shaft (10) is rotatably and reciprocally mounted in the housing and is biassed upwardly by means of a spring (28) which bears on a collar (26) on the shaft. The lower end of the shaft receives a routing head (18) which extends through the sole plate (46) at an angle thereto. A hammer drill is fixed to the upper end of the shaft (10) and the rotational and reciprocating movement of the routing head (18) removes mortar from brickwork. The extent of projection of the routing head (18) is adjustable by means of a bolt (38) which bears on a groove (36) in the rod (34), and the inclination of the routing head is adjustable by means of a bolt (48) which forms part of the pivot. <IMAGE>

Description

SPECIFICATION Router The present invention relates to a router and in particular to a router for removing mortar from brickwork.

Before pointing brickwork (i.e. replacing mortar which has become unsound) it is first of all necessary to remove loose and damaged mortar from between the bricks, otherwise fresh mortar will adhere to unsound mortar and this will shorten the life of the fresh mortar. Traditionally, removal of mortar has been carried out with a hammer and chisel, but this is a slow process, and one which does not ensure that all unsound mortar is removed.

More recently, routing bits for attachment to electric drills have been used, but it has been found that it is difficult to control the position of the drill accurately, resulting in damage to the adjacent brickwork. Furthermore, the depth to which routing takes place is under the control of the operator, and it has been found to be extremely difficult to achieve the desired depth of routing consistently. Also, it has been found necessary to incline the drill bit at an angle to the plane of the wall in order to achieve good routing, and it is not easy to control the inclination accurately.

Portable angle grinders can be used with an abrasive stone cutting disc, but are found to create excessive dust leading to damaged brickwork due to bad visibility. They are also difficult to control because of the need to grind and cut close to the brickwork, which is necessary in order to remove all infirm mortar.

It is an object of the present invention to provide a router which is easy to control accurately, which routs to a constant depth and which cuts at the correct angle.

In accordance with the present invention, a router comprises a wall-engaging base and a rotatable routing head which in use is supported on the base So as to project therefrom and which is arranged on the base such that in use its axis of rotation is inclined to the plane of the wall to be routed.

Preferably, the base is in the form of a sole plate, and the routing head extends through the sole plate. Preferably, the sole plate is at least partially planar.

In a preferred embodiment, the projection of the routing head beyond the level of the base and the inclination of the routing head are adjustable.

Preferably the routing head is axially reciprocable, and preferably the routing head is biassed towards an equilibrium position by resiliently deformable means, e.g. a compression spring.

By way of example only, a specific embodiment of the present invention will now be described with reference to the accompanying drawing, which is a perspective view of an embodiment of router in accordance with the present invention.

The illustrated router is an attachment adapted to be releasably attachable to a hammer drill. The router comprises a central shaft 10 which is rotatably mounted within a tubular metal housing 12. The upper end 14 of the shaft 10 is adapted to be releasably securable in the chuck of a hammer drill and the lower end 16 of the shaft 10 is tubular in order to receive a tungsten carbide routing head 18.

The routing head 18 is securable in the tubular end 16 by means of a screw 20 which passes through a first collar 22 forming part of the tubular end 16 and bears on the shaft of the routing head 18. A felt washer 24 is positioned around the shaft 10 between the collar 22 and the lower end of the tubular metal housing 12 to prevent or reduce the ingress of dust into the housing. A handle 23 is screwed into the wall of the housing 12.

A second collar 26 is provided on the shaft 10 towards its upper end 14. The collar is spaced apart from the upper end of the tubular housing 12, and a compression spring 28 is positioned between, and bars upon the collar 26 and the end of the housing, to bias the shaft 10 upwardly. The collar is held in position on the shaft by means of a screw 30 which passes through the collar and bears on the shaft 10.

A second shorter tube 32 is mounted in parallel with and on the undersurface of the tubular housing 12. A metal rod 34 passes through the tube 32 and is releasably securable in any axial position along its length by means of a threaded securing bolt 38 passing through the wall of the tube 32 and bearing on the rod 34. Rotation of the rod 34 within the tube is substantially prevented by means of an axial groove 36 in the rod, in which the end of the securing bolt 38 is seated. The securing bolt 38 is rotatable by hand, due to the provision of an enlarged, knurled handle 40.

The lower end of the rod 34 is formed into a planar portion 42 and is situated between two parallel upstanding lugs 44 attached to a sole plate 46. A threaded bolt 48 having an enlarged knurled handle 50 passes through the planar portion 42 and the lugs 44, and by adjustment of the bolt 48, the sole plate 50 and the rod 34, and hence the sole plate and the routing head 18, may be secured in different relative inclinations.

The sole plate 50 comprises a rectangular planar portion 52 having an elongate aperture 54, through which the routing head 18 projects. The two parallel fingers formed by the aperture 54 are slightly inclined to the plane of the rectangular portion 52 at their ends 56.

In use the routing head 18 is adjusted to the desired inclination by slackening the bolt 48 and pivoting the sole plate relative to the housing 12, the rod 34 and the routing head 18, about the axis of the bolt 48. The bolt 48 is then tightened to secure the routing head in the correct orientation. The amount by which the routing head projects below the sole plate 46 is also adjusted, by slackening bolt 38 and moving the rod 34 axially relative to the tube 32 until the routing head projects by the desired amount. The bolt 38 is then tightened to secure the routing head in the desired position.

It should be noted that the adjustments of the inclination of the routing head and of its projection past the base of the sole plate are independent of one another. Furthermore, it should be noted that the adjustments may be made without the need for any tools, due to the handles 40,50 on the ends of the bolts 38, 48 respectively. Alternatively the bolts 38 48 may be conventional bolts e.g. Allen screws.

When the adjustment of the routing head have been made the upper end 14 of the shaft 10 is secured in the chuck of a hammer drill. The base of the sole plate 46 is placed in contact with the brickwork to be pointed, and the routing head is aligned with a mortar layer. When the hammer drill is switched on the action of the drill causes the shaft 10, and hence the routing head 18, to rotate and also causes the shaft and routing head to move axially in a reciprocating manner. The spring 28 ensures that the routing head moves back to the illustrated position after having been given each axial impulse from the hammer drill.

The rotation of the routing head 18 removes most of the mortar, and the axial, reciprocating movement of the routing head breaks up lumps of hard mortar which are occasionally found. The routing head is guided along the mortar joints, and it is found that the provision of the handle 23 on the housing 12 allows very accurate routing to be achieved. This is because, although the routing head is rotating and reciprocating, the housing 12, to which the handle is attached, is stationary relative to the sole plate 46 once the adjustments to the routing head have been made. Since the sole plate, in use, is in contact with a relatively flat wall, the motion of the routing head has very little effect on the position of the sole plate and the handle may be used to produce very accurate routing without damaging the adjacent brickwork.

It will be seen that the routing head 18 may be replaced if necessary, simply by slackening the retaining screw 20 removing the routing head replacing it with another routing head and re-tightening the screw. The replacement may be carried out without affecting the adjustments of the inclination and depth of routing.

Although the embodiment described has means for varying the inclination and depth of routing of the routing head the device may, in a simpler form have a rotatable and axially reciprocable routing head arranged at a fixed angle to a sole plate and adapted to project a fixed distance below the base of the sole plate. Alternatively, means for an adjustment for the inclination of, or the depth of routing of, the routing head may be provided.

The invention is not restricted to a device for routing mortar. It may be used to produce grooves in soft building materials such as breeze blocks, thermalite blocks and plaster to allow the positioning of wires or pipes in walls, ceilings and the like.

The invention is not restricted to the details of the foregoing embodiment. In a different embodiment (not illustrated), the second tube 32 which is parallel to the tubular housing 12 is dispensed with and is replaced by a metal support, pivotally mounted on the sole plate and having a trough to receive the underside of the housing 12. A securing bolt passes through the elongate aperture into a threaded hole in the underside of the housing 12, and the head of the bolt bears upon the underside of the support. By adjusting the securing bolt and sliding the housing 12 along the trough, the cutting depth of the router may be varied.

Also in that embodiment the felt washers 24 are replaced with neoprene O-rings situated on the shaft 10 adjacent the upper and lower ends of the housing 12, and there is a provision for mounting the handle 23 on either side of the router, by providing a tapped hole on each side of the housing or the support and by forming a thread on a boss extending from the handle. Also, a further compression spring is positioned between the first collar 22 and the housing 12 in order to re-seat the lower O-ring.

The threaded bolt 48 which is used to adjust the cutting angle may be pre-tightened to a set torque so that it can be varied by hand with moderate force.

Claims

1. A router comprising a wall-engaging base and a rotatable routing head which, in use, is supported on the base so as to project therefrom and which is arranged on the base such that, in use, its axis of rotation is inclined to the plane of the wall to be routed.

2. A router as claimed in claim 1, wherein the base comprises a sole plate and the routing head passes through an aperture in the sole plate.

3. A router as claimed in claim 2, wherein the sole plate is at least partially planar.

4. A router as claimed in any of claims 1 to 3, wherein the routing head is axially reciprocable.

5. A router as claimed in claim 4, wherein the routing head is biassed towards an equilibrium position by resiliently deformable means.

6. A router as claimed in claim 5, wherein the resiliently deformable means comprises a spring.

7. A router as claimed in any of claims 1 to 6, wherein the extent of projection of the routing head from the base is adjustable.

8. A router as claimed in claim 7, wherein the inclination of the routing head is adjustable.

9. A router as claimed in claim 8, further comprising a handle.

10. A router as claimed in claim 9, wherein the handle extends from a portion of the router which, in use, is stationary relative to the base.

11. A router as claimed in any of claims 1 to 10, wherein the router is adapted to be fitted to a drill.

12. A router as claimed in any of claims 1 to 11, comprising a shaft rotatably and reciprocably mounted in a tubular housing, one end of the shaft being adapted to receive a routing head.

13. A router as claimed in claim 12, wherein the tubular housing is slidably mounted on a rod which is pivotally attached to the base.

14. A router substantially as herein described, with reference to, and as illustrated in, the accompanying drawing.