GB2283190A - Lathe faceplate - Google Patents

Abstract

A lathe faceplate assembly 10 comprises an electric heating means 14 for raising the temperature of at least a part of the surface of a lathe faceplate 11. Heating the faceplate 11 enables a workpiece which has been adhered to the faceplate by heat-softenable glue to be removed from the faceplate easily and safely. Fan blades 19 cause air to be drawn through the faceplate when it is rotated. <IMAGE>

Description

Lathe faceplate The present invention relates to lathes and is especially suitable for use with lathes which are intended to be used to turn small items of wood or metal.

In order to turn an item on a lathe, the item, or workpiece, must first be held securely in the lathe.

Most lathes are equipped with a chuck so that a workpiece to be turned may be gripped in the jaws of the chuck. It can, however, be very difficult to obtain a satisfactory grip on small pieces because of the small amount of material available for insertion into the chuck. Also, the jaws may cause damage to more delicate workpieces.

The problem of gripping small pieces of work in a lathe chuck is commonly overcome by gluing the item to be turned onto a piece of scrap wood or metal so that the scrap may be held in the chuck, leaving the workpiece in a position where it may be worked upon in the lathe. Usually, a glue, applied by means of a hot glue gun, is used for attaching the workpiece to the scrap. However, when the workpiece is to be separated from the scrap, which is often done by means of a knife or chisel, there is a risk of damaging it and possibly also of injuring the person carrying out that operation should the knife or chisel slip.

It is an object of the present invention to provide a lathe faceplate which overcomes some, at least, of the foregoing problems.

According to the invention, a lathe faceplate assembly comprises heating means for raising the temperature of at least a part of a surface of a lathe faceplate. By heating the surface of the faceplate, a workpiece which is secured to the faceplate using a heat-softenable glue may be released when the glue has been sufficiently softened by heat conducted from the faceplate.

In one form, the faceplate assembly comprises a chassis plate which is mountable upon a lathe. In this form the faceplate may be spaced apart from the chassis plate to allow the heating means, mounting means and/or other components to be located in the space behind the faceplate. Alternatively, the faceplate may be directly mountable upon a lathe.

The means for mounting the faceplate assembly on a lathe preferably comprises a mounting member which is adapted to be readily located in and gripped by a lathe chuck. As an alternative the faceplate or chassis plate (if present) may have a threaded part by which it may be screwed on to a lathe or a conventional lathe faceplate.

It is advantageous for the faceplate to be easily removable from a lathe or from a faceplate assembly so that a workpiece may be glued to one faceplate whilst another faceplate is installed on the lathe for work upon another workpiece. Where a faceplate assembly has a chassis plate, it may be supplied with more than one chassis plate, each having a different kind of mounting member by which it is mounted on the lathe so that a variety of lathe fittings may be made available.

The heating means preferably comprises an electrical heating element which may be integral with the faceplate or mounted directly behind it. The element may be powered from the mains, optionally via a transformer, or it may be powered by a battery if a suitable low-voltage element is used. An advantage of using a low-voltage element is that the electrical insulation required may be relatively small, and this may allow the faceplate unit to be made relatively compact. The faceplate assembly preferably incorporates a thermostatic control means to prevent the faceplate temperature from rising above a pre-set value.

As less preferred, alternative heating means, a container of hot water or another hot material may be placed in cntact with the faceplate. As a further alternative the heating of the faceplate may be effected by causing a friction-gel to be agitated, preferably using the rotational motion of the lathe.

The faceplate is preferably made from a material which is a good conductor of heat and has a low heat capacity. Copper is an especially suitable material for the faceplate.

The faceplate assembly may additionally comprise cooling means by which the faceplate may be cooled in order for hot, softened glue to cool and harden so that a workpiece may be secured to the faceplate ready to be worked upon. In one preferred form the cooling means comprises an air intake fan secured to the faceplate assembly and arranged so that upon rotation of the faceplate assembly by the lathe, air is drawn into and through the faceplate assembly and thus cools the faceplate. This arrangement has the particular advantage that cooling is effected using the normal rotational movement of the lathe.

The faceplate preferably comprises a centre-pin which extends from the centre of the faceplate for engagement with a depression in the workpiece so that the workpiece may be centred on the faceplate. The centre-pin must not interfere with the application of the workpiece against the surface of the faceplate and so the length of the pin which extends from the faceplate should be variable according to the depth of a punched centre-hole on the base of the workpiece.

Preferably the centre-pin extends through an aperture in the faceplate and is biassed to protrude from the faceplate by means of a compression spring. As an alternative a leaf-spring may be used to bias the centre-pin outwards from the faceplate. The centrepin need not however be sprung; it could be arranged to be adjustable by hand, for example by means of a threaded connection between the pin and the faceplate, or by simply pushing or pulling the pin by hand so that it is the correct length for the job to be done. The centre-pin is preferably able to be depressed to the extent that it is flush with the faceplate and may also be removable from the faceplate. The provision of a removable centre-pin or one which may be made flush with the faceplate enables work to be mounted offcentre on the faceplate - a facility which may be required for certain types of turning work.

The invention will now be further described, by way of example only, with reference to the accompanying drawings which are: Fig.l, a schematic view of a longitudinal section through a faceplate assembly, Fig.2, a schematic view of a transverse section through the faceplate assembly of Fig.l, shown as a view towards the faceplate from beneath the faceplate and Fig.3, which is a simplified typical circuit diagram for the faceplate assembly.

In Figs. 1 and 2 a faceplate assembly 10 comprises a copper faceplate 11 attached to a steel chassis plate 12 by means of bolts or screws 13. The faceplate 11 and chassis plate 12 are parallel and separated by internal spacers (not shown). An electric heating element 14 is located beneath and adjacent to the faceplate 11 so that the faceplate may be heated when the element 14 is switched on. The element draws mains power through a transformer connected by means of an electrical power socket 15. A power indicator lamp 16 is located near the power socket and a thermostatic switch 17 is provided to switch the power supply to the element 15 on and off as required to maintain a pre-set maximum temperature of about 800C whilst power is supplied to the faceplate assembly. The assembly is bounded by a sleeve 18. Four fan blades 19 are secured beneath the element 14 and are shaped and arranged so that when the faceplate assembly is turned by a lathe, air is drawn into the assembly through air inlet 20 and expelled through air outlets 21 located around the perimeter of the assembly. A centre-pin 22 is located in a housing 24 in the centre of the faceplate. The pin protrudes about 5mm from the upper surface of the faceplate 11. The pin is sprung by means of compression spring 23 and may be depressed into the faceplate 11 against the bias of spring 23.

In use, the faceplate assembly 10 is mounted upon a lathe or conventional lathe faceplate by means, such as a member 'for insertion into a lathe chuck, which are not shown in the drawings. Hot glue is then applied to the faceplate from a hot glue gun or by melting the glue directly upon the pre-heated faceplate 11 and a workpiece is applied to the glue, using the pin 22 for centring the workpiece if required. As the glue cools and begins to stiffen, it may be cooled further by turning the faceplate assembly on the lathe so that the circulation of air, which is drawn in by the fan blades 19, behind the faceplate has a cooling effect. When the glue is cold and hard, the workpiece may be turned in the normal way. When it is desired to remove the workpiece from the faceplate the user connects or reconnects the heating element 14 to the power source via socket 15 to cause the faceplate to heat up sufficiently to melt the glue so that the workpiece may be easily removed. Another workpiece may then be applied to the glue remaining on the faceplate before it is cooled and hardened.

Using the faceplate assembly of the invention to melt the glue which holds a workpiece in place on the faceplate, the workpiece may be removed more easily and safely then by the conventional method of breaking it away from a piece of scrap material.

Claims (14)

1. A lathe faceplate assembly comprising heating means for raising the temperature of at least a part of a surface of a lathe faceplate.

2. A lathe faceplate assembly as claimed in Claim 1, wherein said heating means comprises an electrical heating element.

3. A lathe faceplate assembly as claimed in either Claim 1 or Claim 2, further comprising a thermostatic control means to prevent the temperature of the faceplate from rising above a pre-set value.

4. A lathe faceplate assembly as claimed in any of the preceding claims, comprising a chassis plate which is mountable upon a lathe.

5. A lathe faceplate assembly as claimed in any of the preceding claims, comprising a mounting member which is adapted to be readily located in, and gripped by, a lathe chuck.

6. A lathe faceplate as claimed in any of Claims 1-4, comprising a threaded mounting member by which it may be screwed to a lathe or lathe faceplate.

7. A lathe faceplate assembly as claimed in any of the preceding claims, wherein said faceplate is made of copper.

8. A lathe faceplate assembly as claimed in any of the preceding claims, further comprising cooling means.

9. A lathe faceplate as claimed in Claim 8, wherein said cooling means comprises an air intake fan secured to the faceplate assembly and arranged to draw air into and through the faceplate assembly when said faceplate assembly is rotated upon a lathe.

10. A lathe faceplate assembly as claimed in any of the preceding claims, wherein said faceplate comprises a centre-pin, extending from the centre of the faceplate.

11. A lathe faceplate assembly as claimed in Claim 10, wherein said centre-pin extends through an aperture in the faceplate and is biassed to protrude from the faceplate by means of a compression spring.

12. A lathe faceplate as claimed in Claim 10, wherein the length of said centre-pin which extends from the faceplate is manually adjustable.

13. A lathe faceplate as claimed in any of Claims 10-12, wherein said centre-pin is removable from said faceplate.

14. A lathe faceplate assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.