GB2287217A - Laminate trimmers - Google Patents

Abstract

A laminate trimmer offset base 3 comprising a base plate 7 for abutting a workpiece, a body 9 mounted on the base plate 7 for receiving a drive unit 5, a offset spindle 11 carrying a collet 27 for gripping a trimmer bit, the offset spindle 11 being driven by the drive unit 5, during use, and means 29 for opening the collet 27 to release a trimmer bit, wherein the body 9 encloses the spindle 11 and collet 27 adjacent the base plate 7 through which the trimmer bit acts, in use, an the means 29 for opening the collet 27 are spaced from the base plate 7. As a result, support is given to the base plate 7 so that it is less likely to fracture during use. Further, the means for releasing or gripping a trimmer bit is simple and easy to use. <IMAGE>

Description

LAMINATE TRIMMERS This invention relates to laminate trimmers, and in particular to an improvement in the design of laminate trimmer offset bases.

There are currently a number of offset base trimming devices on the market, manufactured by many different companies. In general, however, all of these devices are constructed to approximately the same design. Known devices commonly have a main body which provides a housing for an electric power unit and means for gripping the device.

The power unit is connected by drive means, which may be a drive belt of some description, to the trimming or cutting part of the device. The trimming or cutting device is supported by a base and is contained within a housing which keeps the working parts of the device from coming into contact with a user. The trimming device is offset from the main body of the laminate trimmer to improve the user's ability to trim laminate surfaces that might otherwise be inaccessible, e.g. at the intersection of a laminate surface and a wall. Laminate trimmers having standard bases are readily available for other more accessible applications.

The base of the offset base laminate trimmer is usually substantially triangular in shape, which allows the user to trim the corners of laminate surfaces that are enclosed on two sides by, for example, walls. Within the base there is provided an aperture through which the cutting bit of the laminate trimmer extends. It is this bit which actually cuts the laminate in the desired fashion. Since cutting bits are prone to wear and consequently must be replaced from time to time, it is necessary to be able to remove a cutting bit from the offset base of the laminate trimmer.

In order to facilitate the replacement of broken or worn bits, there is usually provided an aperture in the housing of the cutting part of the laminate trimmer. This aperture has always previously been provided adjacent the apex of the triangular base. By means of this aperture, a user is able to insert a tool into the cutting part of the device in order to release the bit from the chuck or collet of the laminate trimmer. The user is then able to replace the broken or worn bit.

In most cases, the chuck or collet of the laminate trimmer is mounted on a spindle extending through the housing of the cutting part of the tool.

In such cases it is known to stop the spindle from rotating, thereby simplifying access to the chuck for releasing a bit, by means of a hexagonal lock nut on the end of the spindle furthest from the base of the trimmer.

Although the prior art offset base laminate trimmers have been successful, a problem has been identified in that the aperture for access to the chuck of collet of the trimmer results in the base around the chuck being unsupported and hence weak. Since this is the area where pressure is mainly applied to the laminate trimmer, the base can be caused to flex and thereby introduce inaccuracies in the trimming process. Continued flexing may ultimately result in breaking of the base in this region. This flexing and breaking process is due to the fact that the base at the apex of the triangle is essentially totally unsupported.

In order to overcome this problem, it is an aim of the present invention to provide a supported apex of the base around the chuck or collet carrying the cutting bit of the device. Further, the invention aims also to provide a simple and easy means for enabling a user to open a chuck or collet of a tool to release a cutting bit therein.

With the foregoing in mind, the present invention provides a laminate trimmer offset base comprising a base plate for abutting workpiece, a body mounted on the base plate for receiving a drive unit, an offset spindle carrying a collet for gripping a trimmer bit, the offset spindle being driven by the drive unit, during use, and means for opening the collet to release a trimmer bit, wherein the body encloses the spindle and collet adjacent the base plate through which the trimmer bit acts, in use, and the means for opening the collet are spaced from the base plate.

As a result, an improved offset base for a laminate trimmer is provided wherein the base plate is strengthened due to the body of the offset base engaging the base plate to rigidify the plate around the cutting bit and collet.

Preferably the spindle is mounted in the body by annular bearings, thereby allowing the spindle to rotate freely within the body. The annular bearings may comprise a ring of ball bearings, but any other suitable bearing means may also be used.

The means for opening the collet preferably comprise means for preventing rotation of the spindle and means for moving the collet relative to the spindle.

The means for preventing rotation of the spindle may comprise an aperture, spaced from the base plate of the offset base, through which the spindle can be gripped. Alternatively, the means for preventing rotation ofthe spindle may comprise a device mounted on the body which, when depressed, grips the spindle to prevent rotation thereof. Any other appropriate means for gripping the spindle when desired can alternatively be used.

The means for moving the collet relative to the spindle preferably comprise a rod threadedly engaging the collet such that the collet is extended from or withdrawn into the spindle as the thread of the rod releases or engages the collet. Preferably the rod is held in position within the spindle so that it is only the collet which moves when the rod is rotated.

The end of the rod spaced from the collet is preferably exposed on the top of the body on the offset base. In theory, however, the end of the rod could be recessed within the body of the offset base, provided that the end of the rod is still accessible.

The collet is preferably arranged to slide axially within the spindle.

In such a case, the spindle may include internal splines for engaging the collet to allow axial movement thereof. As will be appreciated, of course, it is necessary in the specific embodiment described herein for the rod to be able to rotate relative to the collet so that the collet is moved axially relative to the spindle for opening or closing the collet The spindle preferably includes a rack via which drive from the drive unit is transferred to the spindle, during use.

The base plate is preferably substantially triangular, thereby allowing the tool to gain access to a multitude of tight corners.

According to another aspect of the present invention, there is provided a laminate trimmer comprising a drive unit mounted on an offset base as herein claimed.

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 side elevation showing an offset base laminate trimmer according to the present invention; Figure 2 is a sectional side view of a laminate trimmer offset base according to the present invention; and Figure 3 is a plan view of the laminate trimmer offset base shown in Figure 2.

With reference to the drawings, an offset base laminate trimmer 1 comprises an offset base 3 and a drive unit 5 mounted thereon. The offset base 3 comprises a base plate 7, a body 9 and a spindle 11. The drive unit 5 of the laminate trimmer 1 is gripped by a yoke 13 closed by means of a screw 15, as shown in Figure 2. The drive means 5 includes a drive gear 17 extending into the body 9 of the offset base 3. The gear 17 drives a belt 19 which engages a rack 21 on the exterior of the spindle 11. Thus, when the drive unit 5 is energised, the drive gear 17 rotates to drive the spindle 11 about its vertical axis.

The spindle 11 is mounted in the body 9 by means of annular bearings 23, which comprise rings of ball bearings 25 as shown in Figure 2. Two such bearings 23 are shown.

The spindle 11 is hollow and accommodates a collet or chuck 27 and a threaded rod 29. The collet 27 has a series of slits 31 extending from its free end partially along its length towards the rod 29. The end of the collet 27 distant from the slits 31 is threaded to receive a threaded portion of the rod 29. The other end of the rod 29 is exposed at the top of the body 9 for engagement by a user. Thus, as the rod 29 is turned the collet 27 is moved towards or away from the rod 29 depending upon the direction of rotation of the rod. In this regard, a series of splines 33 are formed on the inside surface of the spindle 11 which engage in corresponding grooves in the collet 27 to ensure that the collet 27 moves axially without rotating relative to the spindle 11.

An opening 35 is formed in the upper region of the body 9 at a position substantially perpendicular to the spindle 11. The aperture 35 allows access to the spindle 11 so that a user can grip the spindle 11 to prevent it rotating during insertion or removal of a cutting bit into the collet 27. Although an aperture 35 is shown, a push button gripping device could, alternatively, be used. If a push button gripping device is used, it is biased outwardly into its normal position to allow free rotation of the spindle 11 and can be pushed inwardly to engage the spindle 11 to prevent rotation thereof.

A brief description of the way in which a cutting bit (not shown) can be applied to the offset base will now be described.

When a tool is entered through the aperture 35 and engages the spindle 11 at its end spaced from the collet 27, the rod 29 can be rotated to drive the collet 27 away from the rod 29. As a result, the collet 27 extends from the base of the spindle 11 and is allowed to flare outwardly due to the slits 31 in the collet 27. A cutting bit (not shown) can then be entered into the collet 27 through a cutting aperture 37 in the base plate 7. Once the cutting bit has been fully inserted, the rod 29 is rotated in the opposite direction to withdraw the collet 27 into the spindle 11 so that the collet 27 closes and grips the cutting bit securely. Once the collet 27 has been fully retracted, the tool can be removed from the aperture 35 so that the spindle 11 is once again free to rotate relative to the body 9, due to the bearings 23.Thus, when the drive unit 5 is energised and the drive gear 17 is rotated, the spindle 11 likewise rotates and drives the cutting bit so that laminate or any other appropriate material can be trimmed.

As will be appreciated, when a cutting bit has become worn through use, it can be readily removed from the collet 27 by using the reverse procedure to that described above. Further, as a result of the present invention, the body 9 of the offset base 3 encloses the spindle 11 and collet 27 and provides strength to the apex 41 of the base plate 7 adjacent the cutting bit. Thus, the apex 41 of the triangular base plate 7 is much stronger and less likely to fracture due to pressure applied thereto.

Furthermore, it is a simple matter to insert or remove a cutting bit from the offset base, as described above.

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 (13)

1. A laminate trimmer offset base comprising a base plate for abutting a workpiece, a body mounted on the base plate for receiving a drive unit, an offset spindle carrying a collet for gripping a trimmer bit, the offset spindle being driven by the drive unit, during use, and means for opening the collet to release a trimmer bit, wherein the body encloses the spindle and collet adjacent the base plate through which the trimmer bit acts, in use, and the means for opening the collet are spaced from the base plate.

2. An offset base as claimed in claim 1, wherein the spindle is mounted in the body by annular bearings.

3. An offset base as claimed in claim 2, wherein the annular bearings comprise a ring of ball bearings.

4. An offset base as claimed in any preceding claim, wherein the means for opening the collet comprise means for preventing rotation of the spindle and means for moving the collet relative to the spindle.

5. An offset base as claimed in claim 4, wherein the means for preventing rotation of the spindle comprise an aperture through which or a device by which the spindle can be gripped.

6. An offset base as claimed in claim 4 or claim 5, wherein the means for moving the collet relative to the spindle comprise a rod threadedly engaging the collet such that the collet is extended from or withdrawn into the spindle as the rod releases or engages the thread of the collet.

7. An offset base as claimed in claim 6, wherein the end of the rod spaced from the collet is accessible from the top of the body on the offset base.

8. An offset base as claimed in any preceding claim, wherein the spindle includes a rack via which drive from the drive unit is transferred to the spindle.

9. An offset base as claimed in any preceding claim, wherein the collet is arranged to slide axially within the spindle.

10. An offset base as claimed in claim 9, wherein the spindle includes internal splines for engaging the collet to allow only axially movement therethrough.

11. An offset base as claimed in any preceding claim, wherein the base plate is substantially triangular.

12. A laminate trimmer offset base substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

13. A laminate trimmer comprising a drive unit mounted on an offset base as claimed in any preceding claim.