GB2523360A

GB2523360A - Woodturning chuck and jig

Info

Publication number: GB2523360A
Application number: GB1403101.7A
Authority: GB
Inventors: David Walter Lobley
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-02-21
Filing date: 2014-02-21
Publication date: 2015-08-26
Also published as: GB201403101D0

Abstract

A woodturning chuck 10 for releasable engagement to a workpiece 14, the chuck comprising: a cup chuck 24; a plurality of fingers 18 coupled at a proximal end to the cup chuck 24, each finger 18 having a distal end circumferentially disposed around and extending upwardly from an inner perimeter of the cup chuck; and a finger driver 12 configured to drive the plurality of fingers 18 between an engaged position in which the fingers engage with a workpiece in a secure engagement, and a release position in which the fingers are disengaged from the workpiece. The plurality of fingers 18 may have a lip 30 to engage with the workpiece, these fingers can be formed from a flexible, resilient material. The finger driver can consist of a threaded bolt 12 and bolt head 42, which when actuated causes the ends of the fingers to move radially inwards, working similar to a collet. The chuck can be mounted to a jig (figure 2a), the jig comprises: A baseplate, a first and second support mounted on the baseplate, and a carriage for mounting a tool on the jig.

Description

Woodturning Chuck and Jig

FIELD OF THE INVENTION

The present invention relates to a chuck and a jig for woodturning, in particular to a device to retain wooden turned stock in a router jig.

BACKGROUND TO THE INVENTION

Woodturning is a technique used to create wooden objects on a lathe, and in particular refers to the woodworking technique where a stationary tool is used to cut and shape a piece of wood which moves relative to the tool.

Faceplate turning is typically used to turn bowls from a solid piece of wood. In faceplate turning, the piece of wood is secured with screws to a faceplate. The faceplate may itself be used to grip the wood while a spigot or recess is formed in the wood, which may subsequently be gripped by a chuck. Alternatively or additionally, a chuck may be used to hold a piece of wood on a lathe/jig. Chucks may take different forms. For example, a cup chuck is a chuck with a deep recess, into which a spigot on the workpiece can be driven. The workpiece is held on one side or at one end by the cup chuck while the other side/end is driled or hollowed out.

Chucks may have indexing holes or may be attached (permanently or detachably) to an indexing head. An indexing head aHows a workpiece to be circularly indexed, i.e. easily and precisely rotated to pre-set angles or circular divisions. A pin may be inserted into the indexing head to lock the head quickly and easily into a particular pre-set position/angle.

Jigs for woodturning are typically custom-made devices to hold a piece of wood and/or guide a tool for use on the wood. Jigs are often tailored to perform a specific job repeatedly and accurately.

The present applicant has recognised the need for an improved chuck and jig for woodturning, in particular for carving patterns in wood surfaces.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a woodturning chuck for releasable engagement to a workpiece, the chuck comprising: a cup chuck; a plurality of fingers coupled at a proximal end to the cup chuck, each finger having a distal end circumferentially disposed around and extending upwardly from an inner perimeter of the cup chuck; and a finger driver configured to drive the plurality of fingers between an engaged position in which the plurality of fingers engage with a workpiece in a secure engagement, and a release position in which the plurality of fingers are disengaged from the workpiece.

In embodiments, the woodturning chuck is suitable for gripping a wooden workpiece by releasable engagement of the cup chuck with a spigot or protrusion extending from the workpiece. The fingers may be connected to or formed from a collar for ease of mounting the fingers within the cup chuck.

Thus, in embodiments, each of the plurality of fingers comprises a lip at the distal end of the finger, wherein each of the lips is inwardly directed towards a centre of the cup chuck, and arranged to engage with a protrusion on the workpiece.

Preferably, the finger driver, when driven into the engaged position, causes the distal ends of the fingers to move radially inward to grip the protrusion on the workpiece.

In embodiments, the finger driver comprises a ring-shaped element disposed within the cup chuck, and the plurality of fingers are retained in the cup chuck by the ring-shaped element.

In embodiments, the finger driver further comprises a threaded bolt extending through the ring-shaped element and the cup chuck, wherein: the plurality of fingers are coupled to the threaded bolt, the threaded bolt comprises a bolt head, wherein the bolt head is in contact with an outer surface of the cup chuck, and rotation of the bolt head moves the ring-shaped element laterally along the bolt, and causes the finger driver to drive the plurality of fingers between the engaged position and the release position.

The ring-shaped element may be sandwiched between the plurality of fingers and a nut threaded onto bolt, where the nut secures the ring-shaped element and fingers on the bolt. Rotating the bolt head or the nut in one direction causes the ring-shaped element to be pushed down into cup chuck, while rotation in the opposite direction causes the ring-shaped element to be moved further out of the cup chuck. Thus, rotation of the driver moves the plurality of fingers between the engaged and disengaged positions.

In embodiments, the cup chuck further comprises two or more locating lugs engageable with the plurality of fingers to prevent tilting and rotation of the fingers when the finger drivers are driven between the engaged position and the release position. The lugs may extend from an inner surface of the base of cup chuck and engage with the fingers. The lugs may minimise tilting of the fingers when the fingers are driven into the engaged position. Furthermore, the lugs may prevent rotation of the fingers.

In an alternative embodiment, each of the plurality of fingers comprises a lip at a distal end of the finger, wherein each of the lips are outwardly directed away from the centre of the cup chuck, and arranged to engage with a recess in the workpiece. In this case, the woodturning chuck is suitable for holding a wooden workpiece having a recessed portion (rather than a spigot/protrusion). The lips of the chuck expand into the recessed portion and apply a force to an inner surface of the recess to secure the In this arrangement, the finger driver, when driven into the engaged position, causes the distal ends of the fingers to move radially outward to engage with a surface of the recess in the workpiece.

Preferably, the finger driver comprises a plunger and a fastener disposed within the cup chuck, wherein the plurality of fingers are retained in the cup chuck by the fastener.

In this arrangement, when the finger driver drives the fingers between the engaged and disengaged positions, the force applied by the plunger may cause the fingers to move in a vertical direction (i.e. opposing the force of the plunger on the fingers). This may not be desirable because if the fingers are permitted to move in a vertical direction, the finger driver may not effectively move the fingers between the engaged and disengaged positions. Thus, in embodiments, the fastener may permit rotation of the finger driver (and thus radial movement of the fingers) but restrict vertical movement of the fingers. The fastener may be provided by a C-clip, an E-clip or other suitable restricting means.

In this arrangement, the finger driver further comprises a threaded bolt extending through the plunger and the cup chuck, wherein: the plurality of fingers are coupled to the threaded bolt, the threaded bolt comprises a bolt head, wherein the bolt head is in contact with an outer surface of the cup chuck, and rotation of the bolt head moves the plunger laterally along the bolt and causes the finger driver to drive the plurality of fingers between the engaged position and the release position. Rotating the bolt head in one direction causes the plunger to be moved down into cup chuck. The plunger applies an outwardly force on the fingers, moving them further apart, i.e. into the engaging position in which they are in contact with a surface of the recess. Rotating bolt head in an opposite direction causes the plunger to be moved out of the cup chuck, thereby reducing the force on the fingers and moving the fingers into a position in which they are not in contact with a surface of the recess.

In each of the above described alternative arrangements, the plurality of fingers may be formed from a flexible, resilient material.

Preferably, the chuck is releasably couplable to an indexing head. The cup chuck may comprise a protrusion on its base, which may be engaged with a recess formed in one face of an indexing head. Additional securing means may be used to secure the cup chuck to the indexing head. The releasable attachment allows attachment of the cup chuck to indexing heads with different indexing.

According to a second aspect of the invention, there is provided a woodturning jig comprising: a baseplate; a first support and a second support mounted on the baseplate; and a carriage for mounting a tool on the jig, the carriage comprising connectors at a first end and a second end of the carriage to slidably connect each of the first end and second end to respective first and second supports, wherein the carriage is laterally disposed between and the first and second supports; and wherein the baseplate comprises a mount for mounting a woodturning chuck as described above.

In embodiments of the jig each of the first and second supports comprises a slot extending along a length of the supports, for slideable adjustment of a height of each of the first and second ends of the carriage relative to the baseplate. The connectors of the carriage connect the first end of the carriage to the first support slot, and the second end of the carriage to the second support slot. The carriage is attached to the supports via the connectors so that it may be positioned above a workpiece mounted on the jig. Each end of the carriage may be raised or lowered independently of the other end.

Thus, in embodiments, the connectors of the carriage are connected to the first and second supports at different heights above the baseplate, such that the carriage is sloped relative to the baseplate.

In embodiments, the connector at the first end is configured such that said carriage is rotatable about a longitudinal axis of the carriage. Thus, the carriage may be tilted, which nay allow a tool to contact a workpiece at an angle relative to the surface of the In embodiments, the baseplate further comprises a plurality of mounting holes disposed at a plurality of positions at a first and a second end of the baseplate, wherein the first and second supports are mountable to the baseplate at the plurality of positions defined by the mounting holes. Thus, the supports may be attached to the baseplate at different points, depending on for example, the length of the carriage. A long carriage may be required for a long workpiece, and the position of one or both of the supports can be adjusted to suit the length of the carriage.

Additionally or alternatively, the baseplate further comprises a slot at each of a first and a second end of the baseplate, wheren the first and second supports are slidably fixable n the slots to provide a continuum of mounting positions for the first and second supports to be mounted to the baseplate.

Preferably, the baseplate comprises a first section and a second section, wherein the second section is rotatably coupled to the first section such that the carriage is positionable at an angle relative to a workpiece mounted on the baseplate.

In embodiments, the first section is rotatably coupled to the second section by a mount extending from a top surface of the first section, and wherein the first and second sections of the baseplate are rotatable about an axis of the mount. Thus, the first and second sections may be rotated about the mount such that the baseplate (and consequently also the carriage) is no longer in-line with the centre of a workpiece mounted on the baseplate. This may enable a workpiece to be worked at oblique angles relative to the centre of the workpiece.

According to a third aspect of the inventon, there is provided a woodturnng assembly comprising: a woodturning chuck as described above releasably coupled to an indexing head, and a woodturning jig as described above, wherein the chuck is releasably couplable to the jig.

In embodiments, the woodturning assembly further comprises a clamp rotatably mounted on a baseplate of the jig, wherein the clamp is configured to releasably secure the chuck to the baseplate and to restrict vertical movement of the indexing head coupled to the chuck. The clamp can be rotated/swivelled between a first, unclamped position and a second, clamped position. In the unclamped position, the clamp is positioned such that it does not contact the indexing head of the chuck. This allows the chuck to be mounted onto or dismounted from the baseplate of the jig. The clamp can be moved to the unclamped position (in which it contacts the indexing head), in order to secure the indexing head to the baseplate.

In embodiments, the woodturning assembly further comprises a pin insertable into an indexing hole of the indexing head to restrict rotation of the indexing head and the chuck. The pin may be inserted in an indexing hole when the indexing head has been moved to the desired position for working a workpiece, in order to prevent the indexing head from moving.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is diagrammatically illustrated, by way of example, in the accompanying drawings, in which: Figures 1 a and lb show respectively a schematic view and a side view of a chuck in an embodiment of the invention; Figures lc and ld show respectively a plan view and a perspective underside view of the chuck of Figure la; Figures 2a to 2c show side views of a jig comprising the chuck of Figure 1 a, according to an embodiment of the invention; Figure 2d shows a side view of the jig holding a wooden workpiece; Figure 2e shows a side view of the jig holding a wooden workpiece and a tool mounted on the jig; Figures 3a and 3b show zoomed-in views of the chuck mounted on a jig; Figure 4a shows a plan view of a carriage of the jig; Figure 4b shows a side view of the chuck mounted on the jig; Figures 5a and 5b respectively show a plan view and a cut-away perspective view of a two-section jig baseplate; Figures 5c and Sd show schematic views of the woodturning jig comprising a two-section baseplate; Figures Se and Sf illustrate side views of the woodturning jig used to work a workpiece along a line running through the centre of the workpiece; Figures 5g and 5h show schematic views of the woodturning jig comprising a two-section baseplate used to work a workpiece obliquely; Figures Si and Sj illustrate side views of the woodturning jig used to work a workpiece obliquely; Fig. 6 illustrates an alternative chuck according to an embodiment of the present invention; and Figs. 7a to 7d show examples of objects patterned using the chuck and jig of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 a shows a schematic view of a woodturning chuck 10 according to the present invention. The woodturning chuck 10 is used to secure a wooden workpiece 14 to a baseplate 28 of a woodturning jig (not shown). Chuck 10 comprises a plurality of sprung fingers 18 disposed circumferentially around an inner perimeter of a cup chuck 24. Preferably, each sprung finger 18 is connected to or formed from a collar 19 for ease of mounting the fingers within the cup chuck 24. The sprung fingers may be formed from flexible, resilient strips of metal. The chuck 10 is releasably couplable to an indexing head 22. Baseplate 28 comprises a recess 43 in a top surface of the baseplate. A mount 20 comprises a protrusion extending from its base which substantially matches the shape and size of the baseplate recess 43. Mount 20 is insertable into the baseplate recess 43. The external diameter of mount 20 substantially matches the internal diameter of a central through-hole in the indexing head 22, such that the indexing head 22 is couplable to the mount 20, as shown in Fig. la. The mount 20 comprises a recess (or may be entirely hollow). As explained in more detail below, the chuck comprises a finger driver which comprises a bolt 12, and a bolt head 42 is arranged to protrude from the base of cup chuck 24. Cup chuck 24 is releasably couplable to the indexing head 22 such that the bolt head 42 sits in the mount 20. Consequently, the cup chuck and sprung fingers are detachable from the indexing head, allowing attachment to indexing heads with different indexing. For alignment purposes, the indexing head 22, the cup chuck 24, the mount 20 and the recess 43 in the baseplate may be aligned along a vertical centre line.

Chuck 10 further comprises a finger driver configured to drive the plurality of fingers between an engaged position in which the fingers engage with a workpiece and a release position in which the fingers are disengaged from the workpiece. In the arrangement depicted in Fig. la, chuck 10 is a protrusion-gripping chuck because the sprung fingers 18 are arranged to grip onto a spigot or protrusion 34 extending from the base of the workpiece 14. Here, the finger driver drives the plurality of fingers between an engaging position in which the fingers grip the protrusion 34, and a release position in which the fingers are disengaged from the protrusion (i.e. where the fingers are not in contact with the protrusion).

In embodiments the finger driver comprises a bolt 12 and a ring-shaped element 40.

The cup chuck 24 and collar 19 each comprise a central hole through which the threaded bolt 12 extends. Bolt 12 couples the cup chuck 24 and the sprung fingers 18 together. Bolt 12 is inserted through the holes of cup chuck 24 and collar 19 such that a bolt head 42 of the bolt is in contact with the external surface of the base of cup chuck 24. A nut 26 threaded onto bolt 12 is in contact with collar 19. A ring-shaped element 40 may be sandwiched between nut 26 and collar 19. Ring-shaped element may be a spread-plate or washer. Rotating nut 26 along the thread of bolt 12 towards the bolt head 42 causes the ring-shaped element 40 to be pushed down into cup chuck 24. Thus, rotation of the driver moves the plurality of fingers between the engaged and disengaged positions. Tightening nut 26 moves the ring-shaped element further into the cup chuck 24 and forces the sprung fingers 18 closer together, i.e. into the engaging position. Similarly, loosenng nut 26 (i.e. rotating the nut away from bolt head 42) moves the ring-shaped element further out of the cup chuck and enables the sprung fingers to move into the disengaged position. (Alternatively, bolt head 43, rather than nut 26, may be rotated to move sprung fingers 18 between the engaged and disengaged positions. In this case, the sprung fingers are attached to the workpiece 14 prior to engaging cup chuck 24 and indexing head 22.) Each of the sprung fingers 18 comprises a lip 30 at the distal end (i.e. the end furthest away from the collar 19). In the embodiment shown in Fig. la, each lip 30 is inwardly directed (i.e. directed towards the centre of the chuck 10). Thus, the lips 30 are arranged to grip the spigot 34 protruding from the base of the workpiece 14 when the fingers are in the engaged position. As mentioned above, tightening nut 26 forces sprung fingers 18 closer together. Thus, the nut 26 can be rotated until the lips 30 tightly grip spigot 34.

The size (diameter) of cup chuck 24 is chosen according to the size (diameter) of the spigot 34 of the workpiece. Broadly speaking, the cup chuck diameter is chosen such that when the sprung fingers 18 are in the disengaged position, the spring fingers 18 are loosely arranged around the spigot 34, and when the spring fingers are moved into the engaged position, the fingers 18 are able to tightly grip on to the spigot 34.

Indexing head 22 is mounted onto the baseplate 28 of a woodturning jig (not shown).

As previously mentioned, the central through-hole of indexing head 22 is engaged with the mount 20 which is couplable to the recess 43 in the top surface of baseplate 28.

Preferably, mount 20 is cylindrical, with a cross-sectional diameter which substantially matches the inner diameter of the central through-hole of indexing head 22. Indexing head 22 is rotatable about mount 20.

In embodiments, two or more locating lugs or similar elements may be provided in the base of the cup chuck 24 to engage with the collar 19 of the sprung fingers. The lugs (not illustrated) may extend from the inner surface of the base of cup chuck 24 and engage with holes in the collar 19. The lugs may minimise tilting of the sprung fingers and collar 19 as the fingers are driven into the engaged position. Furthermore, the lugs may prevent rotation of the collar 19.

In an embodiment, the central hole of collar 19 may be threaded. In this embodiment, in the finger driver may not require a nut 26 to be threaded onto bolt 12 to retain the collar 19 on the bolt.

Figures lb to id respectively show a side view, a plan view and an perspective underside view of the chuck 10. Indexing head 22 comprises a plurality of index holes 38. As mentioned above, the cup chuck 24 and sprung fingers 18 are detachable from indexing head 22, which enables an indexing head with a different number of index holes 38 to be attached. In particular, Fig. lo shows that ring-shaped element 40 may comprise one or more lateral protrusions 41, where each protrusion 41 extends between two adjacent sprung fingers 18. Protrusions 41 may help to retain the relative position between adjacent sprung fingers when the fingers are moved between the engaged and disengaged positions. Fig. ld shows the bolt head 42 engaged in the through-hole of indexing head 22 (without mount 20 present).

Turning now to Figs. 2a to 2c, these show side views of a woodturning jig 36 according to an embodiment of the invention. The chuck 10 of Fig. la is coupled to the mount (not visible) coupled to the baseplate 28 of woodturning jig 36. Baseplate 28 comprises a plurality of mounting holes 29 at each end of the baseplate. Two substantially vertical supports 46 are securely, and removably, fastened to the baseplate 28 via mounting holes 29, such that one support 46 is attached at each end of the baseplate 28. Supports 46 provide support for a lateral carriage 44 upon which a woodturning/ woodworking tool (not shown) is mountable. As illustrated, multiple mounting holes 29 may be provided along the baseplate 28 such that the supports 46 may be attached to the baseplate at different points, depending on the length of carriage 44. A long carriage 44 may be required if the workpiece (not shown) is large, so that the piece can be worked along its full width/length with ease.

Carriage 44 is attached to supports 46 such that the carriage is positioned above chuck and above a workpiece (not shown) attached to chuck 10. The carriage 44 comprises a slot 56 which forms a guide for an electrical woodworking tool (not shown), and a surface of the workpiece is worked by the tool through slot 56. Carriage 44 can be raised and lowered so that the tool can be brought into contact with workpieces of different heights, and/or to create deeper grooves/patterns in the workpiece surface.

Each support 46 comprises a support slot 54 extending along all or part of the length of the support 46. Carriage 44 comprises connectors at each end to attach the carriage 44 to the support slot 54 of each support 46. In the illustrated embodiment, the carriage 44 comprises a connector 52, such as a bolt, at one end and a universal joint 48 at the other end. As shown, the bolt head of connector 52 is affixed to carriage 44 (e.g. by welding) and the bolt itself is passed through slot 54 of a support 46. The bolt is moved to the desired position in the slot, i.e. to position the carriage 44 at a particular height above the workpiece, and fastened in place via a nut threaded onto the bolt.

The unversaI joint 48 may comprise a ball and socket joint and may further comprise means of restraining relative movement of the ball and socket joint. The universal joint is described in more detail below with respect to Fig. 4b.

Thus, as shown in Fig. 2b, the universal joint 48 enables carriage 44 to be tilted, to allow a tool woodworking tool to work on the workpiece at an angle relative to the surface of the workpiece. Furthermore, as shown in Fig. 2c, the connector 52 or the universal joint 48 may be positioned at different heights in the slot 56 of their respective supports 46, so that the carriage 44 is sloped relative to the surface of a workpiece.

For example, the carriage position shown in Fig. 2c may enable cuts/grooves to be made along the surface of the workpiece which are deeper at a first position (i.e. where the carriage is in closer contact with the workpiece) and shallower at a second position (i.e. where the carriage is further away from the workpiece). Consequently, the carriage 44 position can be adjusted to allow the workpiece to be worked at different angles to create, for example, the patterns shown in Figs. 7a to 7d.

As shown in Figs. 2a to 2c, connector 52 is coupled to carriage 44 via hinge 50. The hinge 50 enables carriage 44 to be moved relative to connector 52, for finer adjustment/positioning of the carriage 44 relative to the workpiece. Figure 2d shows a side view of the jig holding a wooden workpiece 14, and Figure 2e shows a view of a tool mounted on the jig. Thus, the carriage 44 may be sloped and/or tilted in order for a tool mounted on the carriage to contact the workpiece 14 at the desired position and angle to form, for example, the types of grooves/cuts in the workpiece illustrated in Fig. 2e.

Turning now to Figures 3a and 3b, these show zoomed-in views of chuck 10 mounted on the baseplate 28 of the woodturning jig 36. As mentioned earlier, the central through-hole of indexing head 22 is engaged with a mount 20 (not shown) coupled to a recess formed in the top surface of baseplate 28. Indexing head 20 is rotatable about mount 20. A latch or clamp 62 is rotatably mounted on the baseplate 28, such that it can be rotated/swivelled between a first, unlatched position (as shown in Fig. 3a) and a second, latched position (as shown in Fig. 3b). In the unlatched position, the clamp 62 is positoned such that it does not contact the indexing head 22 of the chuck 10. This allows the chuck 10 to be mounted onto or dismounted from the baseplate 28. Clamp 62 is moved to the latched position (in which it contacts the indexing head 22), in order to secure the indexing head to the baseplate. Clamp 62 may be securely fastened in the latched position to prevent the indexing head from being lifted off the baseplate by, for example, tightening a bolt used to mount the Clamp 62 to the baseplate. Figs. 3a and 3b also show pin 60, which may be inserted into one of the indexing holes 38 to prevent rotation of indexing head 22.

Figure 4a shows a plan view of the carriage 44 of the jig 36, and Figure 4b shows a side view of the chuck 10 mounted on the jig 36. As mentioned earlier, one of the connectors connecting carriage 44 to the supports 46 may be a universal joint 48, and in particular, may comprise a ball and socket joint. The universal joint 48 n the form of a ball joint allows a range of vertical articulation of the carriage relative to the baseplate in order to permit a tool to be directed at an angle relative to the surface of the workpiece. As illustrated in Fig. 4b, the universal joint 48 also comprises means restraining relative movement of the ball and socket joint. Specifically, the shape of the socket restricts movement of the ball of joint 48, and thus, permits the carriage 44 to be moved through a limited range of angles.

Figures 5a and 5b respectively show a plan view and a cut-away perspective view of a two-section jig baseplate 66. The woodturning jig 36 may be comprised of a one-section baseplate 28 (as illustrated in Figs. 2a to 2e), or a two-section baseplate 66, as shown here. The one-section baseplate 28 is formed of a single piece of material (e.g. metal) and forms a rigid base for the woodturning jig. As shown in Figs. 2d and 2e, the carriage 44 and baseplate 28 are in-line with a line running through the centre of workpiece 14. The workpiece 14 is worked along this line running through its centre. The two-section baseplate 66 illustrated in Figs. 5a and Sb comprises a first section 68 and a second section 70, where the second section 70 is rotatably mounted on to a mount extending from a top surface of the first section 68. The sections 68, 70 may be rotated about the mount such that the baseplate 66 (and consequently also a carriage) is no longer in line with a wcrkpiece mounted on the baseplate 66. (The mount may be permanently attached to the first section 68. When the first and second sections are coupled together, the mount may protrude from the top surface of the second section 70 such that the mount may also provide the means to couple the indexing head and cup chuck to the baseplate). Advantageously, ths enables a workpiece to be worked at oblique angles relative to the centre of the workpiece. This is described in more detail with reference to Figs. 5c to 5j below.

As shown in Fig. Sb, the first section 68 and second section 70 each comprise cut-away portions such that when the sections 68 and 70 are mounted together, the final baseplate 66 has a substantially smooth surface. Mount 20 protrudes from the cut-away portion of first section 68, while the cut-away portion of second section 70 comprises a hole 72 with a diameter that substantially matches the outer diameter of mount 20. The two-section baseplate 66 is formed by mounting section 70 on to the mount 20 of section 68, and the two sections 68, 70 are rotatable relative to each other about mount 20. Mount 20 extends out of the top surface of section 70, to enable the indexing head of chuck 10 to be mounted onto the baseplate 66. As previously described, the central through-hole of the indexing head is engaged with the mount 20 extending from the top surface of baseplate 66. The indexing head is rotatable about mount 20.

Baseplate 66 may comprise a plurality of mounting holes at each end of the baseplate (as described earlier with reference to Figs 2a to 2c), which allow the supports to be attached to the baseplate 66 at different discrete points. Alternatively, baseplate 66 may comprise baseplate tracks 64 at each end. The baseplate tracks 64 shown here enable the supports (not shown) to be moved along a continuum provided by the tracks. When the two-section baseplate 66 is in-line with the carriage of the woodturning jig, the supports may be attached to the baseplate at different points, depending on the length of carriage. For example, a long carriage may be required if a workpiece is large, so that the piece can be worked along its full width/length with ease. When the two sections of the baseplate 66 are rotated relative to each other, such that a carriage is oblique to the centre of a workpiece, the position of one or more of the supports may need to be adjusted to tolerate the new oblique position of the carriage therebetween. Thus, the baseplate tracks 64 allow the supports to be moved into a position required to tolerate the length or angle of the carriage. (In a jig with a fixed-length carriage, the baseplate tracks 64 are required to tolerate the angle of the carriage only).

Figures 5c and Sd show schematic views of the woodturning jig comprising a two-section baseplate 66. Specifically, Fig. 5c shows a plan view of the jig (without a carriage) on which a workpiece 14 is mounted, and Fig. Sd shows the same view with the carriage 44. The baseplate 66 and the carriage 44 are both in-line wth the centre of workpiece 14, which allows the workpece to be worked along a line running through its centre. The supports of the jig (not shown) may be moved along baseplate tracks 64 (as indicated by the arrows) to accommodate the length of the carriage 44. Figures.

5e and Sf illustrate side views of the woodturning jig 36 used to work the workpiece 14 along a line running through the centre of the workpiece.

Turning now to Figure 5g, theis shows a schematic view of the woodturning jig comprising a two-section baseplate which is used to position the carriage 44 at angles relative to the centre of the workpiece 14. The dashed arrow indicates movement of the first section 68 of baseplate 66 relatve to the section 70. As the first section 68 is rotated about the mount 20, the carriage 44 is no longer in-line with the centre of the workpiece 14, enabling the workpiece to be worked at an angle relative to the centre. As described above, the position of one or both of the supports (not shown) may need to be adjusted along the tracks 64 in order to tolerate the new position of carriage 44. As shown in Fig. 5g, the first section 68 of the baseplate 66 can be rotated to the left (relative to the second section 70). Equally, the first section 68 may be rotated to the right, relative to the second section 70. Additionally or alternatively, the second section 70 may be rotated while the first section 68 is kept static, or both sections 68, 70 may be moved relative to each other. Figures 5h and 5i Ilustrate side views of the woodturning jig 36 used to work the workpiece 14 obliquely. As described earlier, the carriage 44 may also be tilted and/or sloped, by altering the angle of the carriage 44 relative to a surface of the workpiece (Fig. 5h) and/or altering the height of one end of the carriage (Fig. Si).

Turning now to Figure 6, this shows an embodiment of the chuck that is generally similar to what has been described above both in terms of construction and operation. The same reference numerals have been used in the embodiment of Figure 6 to designate parts that are in common with the previous embodiments, and the following description is directed primarily at constructional and operation features that differ from the previous embodiment.

The constructional differences are essentially confined to the means to engage with a workpiece 14, which here comprises a recess 32 in the base of the workpiece (rather than a spigot/protrusion as in Fig. la). Thus, in the arrangement shown in Fig. 6, the chuck 74 is a recess-engaging chuck because the sprung fingers 18 are arranged to expand into the recess. Chuck 74 comprises a plurality of sprung fingers 18 disposed circumferentially around an inner perimeter of a cup chuck 24. Preferably, each sprung finger 18 is connected to or formed from a collar 19 for ease of mounting the fingers within the cup chuck 24. The sprung fingers may be formed from flexible, resilient strips of metal. The cup chuck 24 and collar 19 are releasably attached to an indexing head 22, as described with reference to Fig. la.

The chuck 74 further comprises a finger driver configured to drive the plurality of fingers between an engaging position in which the fingers expand into the recess and are in contact with a surface of the recess, and a release position in which the fingers are close together and not in contact with the surface of the recess.

In embodiments, the finger driver comprises a bolt 12 and a plunger or pressure disc 16. The cup chuck 24 and collar 19 each comprise a central hole through which the threaded bolt 12 extends. Bolt 12 couples the cup chuck 24 and the sprung fingers 18 together. Bolt 12 is inserted through the holes of cup chuck 24 and collar 19 such that a bolt head 42 of the bolt is in contact with the external surface of protrusion 43. The plunger or pressure disc 16 (threaded onto bolt 12) is located within the circumference defined by sprung fingers 18. Rotating bolt head 42 in one direction causes the pressure disc 16 to be moved down into cup chuck 24. The pressure disc 16 applies an outwardly force on the sprung fingers 18, moving them further apart, i.e. into the engaging position. Rotating bolt head 42 in an opposite direction causes the pressure disc 16 to be moved out of the cup chuck 24, thereby reducing the force on the sprung fingers 18, i.e. the fingers are moved into a position in which they are not in contact with a surface of the recess. Thus, the sprung fingers 18 are moveable between an engaged and a disengaged position.

Each of the sprung fingers 18 comprises a lip 30 at the distal end (i.e. the end furthest away from the collar 19). In the embodiment shown in Fig. 6, each lip 30 is outwardly directed (i.e. directed away from the centre of the chuck 74). Thus, the lips 30 are arranged to expand into a recess 32 in the base of the workpiece 14 when moved into the engaging position by the finger driver.

The size (diameter) of cup chuck 24 is chosen according to the size (diameter) of the spigot 34 of the workpiece. Broadly speaking, the cup chuck diameter is chosen such that when the sprung fingers 18 are in the disengaged position, the spring fingers 18 do not contact the surface of the recess 32, and when the spring fingers are moved into the engaged position, the fingers 18 expand into the recess 32 and apply a force to the surface of the recess.

When the finger driver drives the fingers 18 of chuck 74 between the engaged and disengaged positions, the fingers 18 may also move in a vertical direction, i.e. along the length of the bolt 12. This may not be desirable because if the fingers are permitted to move in a vertical direction, moving the plunger position may not cause the fingers to move between the engaged and disengaged position. Thus, in embodiments, the finger driver may further comprise a fastener that permits rotation of the bolt 12 (and thus radial movement of the fingers) but restricts vertical movement of the fingers (i.e. along bolt 12). The fastener may be provided by a C-clip, an E-clip or other suitable restricting means.

Figs. 7a to 7d show examples of wooden bowls patterned using the chuck and jig of the present invention. As described above, a workpiece may be worked in-line and examples of such in-line carving 76 are shown here. Examples of angled carving 78, achieved by positioning the carriage at an angle relative to the centre of the workpiece (i.e. by using a two-section baseplate), are also shown. Consequently, the carriage 44 position can be adjusted to allow the workpiece to be worked at different angles to create, for example, the patterns shown in Figs. 7a to 7d. Adjusting the height of the carriage so that it is sloped relative to the surface of a workpiece may enable cuts/grooves to be made along the surface of the workpiece which are deeper at a first position (i.e. where the carriage is in closer contact with the workpiece) and shallower at a second position (i.e. where the carriage is further away from the workpiece). Tilting the carriage may enable a woodworking tool to work on the workpiece at an angle relative to the surface of the workpiece, to create curved indentations for instance.

No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto.

Claims

CLAIMS: 1. A woodturning chuck for releasable engagement to a workpiece, the chuck comprising: acupchuck; a plurality of fingers coupled at a proximal end to the cup chuck, each finger having a distal end circumferentially disposed around and extending upwardly from an inner perimeter of the cup chuck; and a finger driver configured to drive the plurality of fingers between an engaged position in which the plurality of fingers engage with a workpiece in a secure engagement, and a release position in which the plurality of fingers are disengaged from the workpiece.
2. A woodturning chuck as claimed in claim 1 wherein each of the plurality of fingers comprises a lip at the distal end of the finger, and wherein each of the lips are inwardly directed towards a centre of the cup chuck, and arranged to engage with a protrusion on the workpiece.
3. A woodturning chuck as claimed in claim 2, wherein the finger driver, when driven into the engaged position, causes the distal ends of the fingers to move radially inward to grip the protrusion on the workpiece.
4. A woodturning chuck as claimed in any preceding claim, wherein: the finger driver comprises a ring-shaped element disposed wthin the cup chuck, and wherein the plurality of fingers are retained in the cup chuck by the ring-shaped element.
5. A woodturning chuck as claimed in claim 4, the finger driver further comprising a threaded bolt extending through the ring-shaped element and the cup chuck, wherein: the plurality of fingers are coupled to the threaded bolt, the threaded bolt comprises a bolt head, wherein the bolt head is in contact with an outer surface of the cup chuck, and rotation of the bolt head moves the ring-shaped element laterally along the bolt, and causes the finger driver to drive the plurality of fingers between the engaged position and the release position.
6. A woodturning chuck as claimed in any preceding claim wherein the cup chuck further comprises two or more locating lugs engageable with the plurality of fingers to prevent tilting and rotation of the fingers when the finger drivers are driven between the engaged position and the release position.
7. A woodturning chuck as claimed in claim 1 wherein each of the plurality of fingers comprises a lip at a distal end of the finger, and wherein each of the lips are outwardly directed away from the centre of the cup chuck, and arranged to engage with a recess in the workpiece.
8. A woodturning chuck as claimed in claim 8, wherein the finger driver, when driven into the engaged position, causes the distal ends of the fingers to move radially outward to engage with a surface of the recess in the workpiece.
9. A woodturning chuck as claimed in claim 7 or 8, wherein the finger driver comprises a plunger and a fastener disposed within the cup chuck, and wherein the plurality of fingers are retained in the cup chuck by the fastener.
10. A woodturning chuck as claimed in claim 9, the finger driver further comprising a threaded bolt extending through the plunger and the cup chuck, wherein: the plurality of fingers are coupled to the threaded bolt, the threaded bolt comprises a bolt head, wherein the bolt head is in contact with an outer surface of the cup chuck, and rotation of the bolt head moves the plunger laterally along the bolt and causes the finger driver to drive the plurality of fingers between the engaged position and the release position.
11. A woodturning chuck as claimed in claim 9 or 10 wherein the fastener permits rotation of the bolt while restricting latera movement of the fingers in the cup chuck.
12. A woodturning chuck as claimed in claim 11 wherein the fastener is a C-clip or an E-clip.
13. A woodturning chuck as claimed in any preceding claim, wherein each of said plurality of fingers is formed from a flexibe, resilient material.
14. A woodturning chuck as claimed in any preceding claim wherein the chuck is releasably couplable to an indexing head.
15. A woodturning jig comprising: a baseplate; a first support and a second support mounted on the baseplate; and a carriage for mounting a tool on the jig, the carriage comprising connectors at a first end and a second end of the carriage to slidably connect each of the first end and second end to respective first and second supports, wherein the carriage is laterally disposed between and the first and second supports; and wherein the baseplate comprises a mount for mounting a woodturning chuck according to any one of claims ito 14 onto the jig.
16. A woodturning jig as claimed in claim 15 wherein each of the first and second supports comprises a slot extending along a length of the supports, for slideable adjustment of a height of each of the first and second ends of the carriage relative to the baseplate.
17. A woodturning jig as claimed in claim 15 or 16 wherein the connectors of the carriage are connected to the first and second supports at different heights above the baseplate, such that the carriage is sloped relative to the baseplate.
8. A woodturning jig as claimed in any one of claims 15 to 17 wherein the connectors at the first end is configured such that said carriage is rotatable about a longitudinal axis of the carriage.
19. A woodturning jig as claimed in any one of claims 15 to 18 wherein the baseplate further comprises a plurality of mounting holes disposed at a plurality of positions at a first and a second end of the baseplate, wherein the first and second supports are mountable to the baseplate at the plurality of positions defined by the mounting holes.
20. A woodturning jig as claimed in any one of claims 15 to 19 wherein the baseplate further comprises a slot at each of a first and a second end of the baseplate, wherein the first and second supports are slidably fixable in the slots to provide a continuum of mounting positions for the first and second supports to be mounted to the baseplate.
21. A woodturning jig as claimed in any of claims 15 to 20 wherein the baseplate comprises a first section and a second section, wherein the second section is rotatably coupled to the first section such that the carriage is positionable at an angle relative to a workpiece mounted on the baseplate.
22. A woodturning jig as claimed in claim 21 wherein the first section is rotatably coupled to the second section by a mount extending from the a top surface of the first section, and wherein the first and second sections of the baseplate are rotatable about an axis of the mount.
23. Awoodturning assembly comprisng: a woodlurning chuck according to claims 1 to 14, and a woodlurning jig according to any one of claims 13 to 22, wherein the chuck is releasably couplable to the jig.
24. A woodturning assembly as claimed in claim 23 further comprising a clamp rotatably mounted on a baseplate of the jig, wherein the clamp is configured to releasably secure the chuck to the baseplate and to restrict vertical movement of the indexing head coupled to the chuck.
25. A woodturning assembly as claimed in claim 23 or 24 further comprising a pin insertable into an indexing hole of the indexing head to restrict rotation of the indexing head and the chuck.
26. A woodturning chuck substantially as hereinbefore described, with reference to, and as illustrated in any one of the embodiments shown in the accompanying drawings Figures la to id and Figure 6.
27. A woodturning jig substantially as hereinbefore described, with reference to, and as illustrated in any one of the embodiments shown in the accompanying drawings Figures 2a to 2e and Figures 5a to Si.