GB2075911A - Apparatus for use in cutting a mortice - Google Patents

Abstract

A rotary cutting tool 10 is guided for movement along a rectilinear path, the length of which can be adjusted by stops (36, 37). The apparatus is clamped to the edge of a door by pairs of clamping elements (17 and 18, 19 and 20) guided in sideways 22 and moved towards and away from each other by screw threads of opposite hand provided on screws 25 and 31.

Description

SPECIFICATION Apparatus for use in cutting a mortice.

The present invention relates to apparatus for use in cutting a mortice, particularly a mortice in an edge of a door to receive a lock or latching device.

Timber doors are normally supplied by the manufacturer without any lock or latching device being fitted and without any mortice to receive a lock or latching device, because there is available a wide variety of locks and latching devices, many of these different in size. Purchasers of doors require freedom to select a lock or latching device for each door.

Many of the locks fitted to timber doors are mortice locks, that is to say the lock is received in a mortice cut in an edge of the door so that a bolt of the lock can be caused to protrude from the edge of the door orto be retracted into the door. Similarly, latching devices fitted to timber doors are normally mortice latches. Mortices to receive locks and latching devices are normally formed by boring a row of holes in the edge of the door and then removing further timber by means of a chisel. It is important that the larger surfaces of the mortice should be paralel to the faces of the door, spaced equally from a medial plane of the door and spaced apart just sufficiently far to receive between them the lock or latching device.Furthermore, the distance which the mortice extends into the door from the edge thereof should correspond closely to the corresponding dimension of the lock or latching device in order that the door is not unduly weakened by the mortice.

Considerable skill and time is needed to form by means of hand tools a mortice which meets these criteria.

According to the present invention, there is provided apparatus comprising a carrier having a bearing for supporting a cutting tool for rotation relative to the carrier about an axis, a guide adapted to guide the carrier along a rectilinear path perpendicular to the axis, a pair of clamping elements and driving means for moving the clamping elements towards and away from each other wherein the clamping elements have respective clamping faces, both of which are parallel to the axis and to the path of the carrier and which define between them a gap, and the driving means is so associated with the clamping elements and guide that, during relative movement of the clamping elements by the driving means, said clamping faces remain spaced equally from a plane which contains the axis and is parallel to the clamping faces.

By means of apparatus in accordance with the invention, a rotary cutting tool can be supported on a door for movement along a path such that an axis of the tool remains in a medial plane of the door.

Furthermore, this relationship between the cutting tool and door is established automatically, irrespective of the thickness of the door.

Each clamping face of the apparatus has a surface which contacts a face of the door in use of the apparatus and which is of sufficient area to enable the apparatus to be firmly clamped to the door without damaging the door.

The apparatus may include two pairs of clamping elements, one pair adjacent the one end of the guide and the other pair adjacent to the other end of the guide.

The driving means preferably comprises, for each pair of clamping elements, a screw having first and second portions formed with respective threads of opposite hand but equal pitch and engaged with corresponding female screw threads formed in the clamping elements and having a third portion which cooperates with means on the guide to restrain longitudinal movement of the screw during rotation.

Adjustable stops may be provided for limiting the travel of the carrier along the guide.

In the preferred construction, there is provided a lever connected by a link with the carrier for moving the carrier along the guide, the link being pivoted on the carrier for movement relative thereto about a link axis, the lever being pivoted on the guide for movement relative thereto about a lever axis, the lever axis lying to one side of the plane in which the link axis moves and a pivotal connection between the lever and link lying to the opposite side of that plane.

An example of apparatus embodying the invention will now be described, with reference to the accompanying drawing, which shows a perspective view of apparatus in accordance with the invention mounted on a door and.a rotatable cutting tool shown withdrawn from the apparatus.

The apparatus shown in the accompanying drawing is intended to be used for supporting a rotatable cutting tool 10 with an axis 11 of the tool lying in a medial plane of a door 12 and for guiding the tool for movement along a path such that the axis 11 remains in the medial plane of the door. The apparatus includes a carrier 13 having a bearing 14, which may be a ball bearing or a plurality of aligned ball bearings, for receiving the tool 10. There extend through the carrier 13 in sliding engagement therewith a pair of rectilinear, parallel guide elements 15 between which there is a gap aligned with the bearing 14.

The elements 15 are parts of a guide 16 provided with an upper pair of clamping elements 17 and 18 and a lower pair of claniping elements 19 and 20.

When the apparatus is clamped to a vertical door, as shown in the drawing, the clamping elements 17 and 18 lie directly above the clamping elements 19 and 20.

An upper part 21 of the guide is formed with an undercut slideway 22 extending in a direction from one guide element 15 to the other. Each of the upper clamping elements 17 and 18 is provided with a projection of complementary shape which engages in the slideway and thereby guides the clamping element for movement towards and away from the other clamping element of the upper pair. The guide elements have flat clamping faces which face towards each other and engage the faces 24 of the door 12.

For driving the clamping elements 17 and 18 towards and away from each other there is provided a screw 25 having a first end portion 26 formed with a screw thread and engaged with a femalse screw thread formed in the clamping element 17 and a second end portion 27 also formed with a screw thread and engaged with a female screw thread formed in the clamping element 18. The threads on the end portions 26 and 27 are of opposite hand.

An intermediate portion of the screw 25 extends through an aperture in a block 28 on the upper guide part 21, the block lying between the guide elements 17 and 18. The block carries a grub screw 29 having a tip which engages in a peripheral groove formed in the intermediate part of the screw 25 to restrain the screw against longitudinal movement relative to the guide 16. On one end of the screw 25 there is provided a handle 30.

The lower clamping elements 19 and 20 are identical with the upper clamping elements 17 and 18 and are mounted on the guide 16 in an identical manner. Thus, there is provided for driving the lower clamping elements towards and away from each other a screw 31 identical with the screw 25 and anchored in a similar manner against longitudinal movement.

For moving the carrier 13 along the guide elements 15, there is provided a lever 32, a free end portion of which constitutes a handle. The lever is pivoted on the upper guide part 21 for movement relative thereto about a lever axis 33 parallel to the axis 11. The lever is connected to the carrier 13 by a link 34, one end portion of which is pivoted on the carrier for movement relative thereto about a link axis 35 also parallel to the axis 11. The link axis 35 extends between the guide elements 15. The link 34 extends from the axis 35 past one of the guide elements 15 and is pivotally connected at its end remote from the axis 35 with the lever 32.

It will be noted that a plane containing the lever axis 33 and the link axis 35 is inclined to the plane in which the axis 11 moves when the carrier 13 moves along the guide elements 15. The lever axis 33 lies to one side of a plane in which the link axis 35 moves and the pivotal connection between the lever and the link lies to the opposite side of that plane. In the particular example shown, the link axis 35 and axis 11 move in a common plane.

For limiting travel of the carrier 13 along the guide elements 15, there are provided adjustable stops 36 and 37. The stop 36 is in the form of a screw which projects upwardly from the carrier 13 and can be screwed into and out of the carrier. A free end of the screw is engageable with an abutment 38 on the upper guide part 21. The stop screw 37 projects downwardly from the carrier for engagement with a corresponding abutment 39 on the lower guide part.

When the apparatus is to be used, the screws 25 and 31 are rotated to separate the clamping ele ments of each pair sufficiently to enable the door 12 to be received between the clamping elements with the edge of the door engaged with the upper guide part 21 and with the corresponding lower guide part.

The carrier 13 is then clear of the edge of the door.

The screw 25 is then rotated in a direction to drive the upper clamping elements 17 and 18 towards each other into pressure contact with the faces 24 of the door and the lower clamping elements 19 and 20 are similarly engaged with the faces of the door. The screw threads on the first and second portions 26 and 27 of the screw 25 and on the corresponding portions of the screw 31 all have the same pitch and the screws are so arranged that the clamping faces 23 of the clamping elements 17 and 18 are always equally spaced from the plane in which the axis 11 moves and the clamping faces of the elements 19 and 20 also are equally spaced from that plane.

Thus, the establishment of pressure contact between the clamping elements and the faces of the door ensures that the axis 11 lies in a medial plane of the door. The clamping faces of the clamping elements are all parallel to each other and to the plane in which the axis 11 moves.

The stop screws 36 and 37 are adjusted to provide a stroke of the carrier 13 corresponding to the vertical dimension of the lock or latching device to be fitted in the door.

The cutting tool 10 is introduced into the bearing 14 from the side thereof which faces towards the edge of the door 12 priorto clamping of the apparatus to the door. The cutting tool is moved sufficientlyfarthrough the bearing to avoid interference between the cutting tool and door during clamping of the apparatus to the door. After the apparatus has been clamped to the door, there is applied to the cutting tool an electrically-driven hand drill or other device (not shown) for rotating the cutting tool. Penetration of the cutting tool into the door is limited by an adjustable collar 40 on a shank of the cutting tool which protrudes through the bearing 14. The cutting tool is moved by means of the lever 32 along the stroke permitted by the stop screws 36 and 37 to cut out the required mortice.

Claims (10)

1. Apparatus comprising a carrier having a bearing for supporting a cutting tool for rotation relative to the carrier about an axis, a guide adapted to guide the carrier along a rectilinear path perpendicular to the axis, a pair of clamping elements and driving means for moving the clamping elements towards and away from each other, wherein the clamping elements have respective clamping faces, both of which are parallel to the axis and to the path of the carrier and which define between them a gap, and the driving means is so associated with the clamping elements and guide that, during relative movement of the clamping elements by the driving means, said clamping faces remain spaced equally from a plane which contains the axis and is parallel to the faces.

2. Apparatus according to claim 1 which includes two pairs of clamping elements, one pair adjacent to one end of the guide and the other pair adjacent to the other end of the guide.

3. Apparatus according to claim 1 or claim 2 wherein the driving means comprises, for the or each pair of clamping elements, a screw having first and second portions formed with respective threads of opposite hand but equal pitch and engaged with corresponding female screw threads formed in the clamping elements and having a third portion which cooperates with means on the guide for restraining longitudinal movement of the screw during rotation.

4. Apparatus according to any preceding claim further comprising adjustable stops for limiting travel of the carrier along the guide.

5. Apparatus according to any preceding claim further comprising a lever pivoted on the guide for movement relative thereto about a lever axis and connected with the carrier for moving the carrier along the guide.

6. Apparatus according to claim 5 wherein the lever is connected with the carrier by a link, the link has one end portion pivoted on the lever and has an opposite end portion pivoted on the carrier for movement relative to the carrier about a link axis.

7. Apparatus according to claim 6 wherein a plane containing the lever axis and the link axis is inclined to the plane in which the axis of the cutting tool moves.

8. Apparatus according to claim 7 wherein the lever axis lies to one side of a plane in which the link axis moves and the pivotal connection between the lever and the link lies to the opposite side of that plane.

9. Apparatus substantially as herein described with reference to and as shown in the accompanying drawing.

10. Any novel feature or novel combination of features disclosed herein or in the accompanying drawing.