GB2192820A

GB2192820A - Pantograph copy attachment for woodturning lathes

Info

Publication number: GB2192820A
Application number: GB08615238A
Authority: GB
Inventors: Barry John Beck
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-06-23
Filing date: 1986-06-23
Publication date: 1988-01-27
Anticipated expiration: 2006-06-23
Also published as: GB8615238D0; GB2192820B

Abstract

A pantograph copy attachment has a main space frame (K) which can be fitted over the bed rails of most types of woodturning lathes. A tool holder beam (P) slides over the space frame rails independently of the lathe bed rails. A sliding holder (F) for the pantograph can be moved to different positions along the rails to obtain an optimum working position for the pantograph assembly. The space frame supports the pattern between centres (DD). The complete pantograph assembly can be lifted off or parked at the rear of the space frame when not in use. <IMAGE>

Description

SPECIFICATION Pantograph copy attachment for woodturning lathes This invention relates to a copy attachment for woodturning lathes.

Copy attachments are well known in their ability to assist the wood turner to reproduce turned items between centres, more easily and more accurately, reducing the need for individual measurement of each component.

Copy attachments have taken various forms throughout the years but most which are used by the amateur hobbist, or the small time professional take the form of a single point cutting tool traversed over the machine bed length and guided by rollers or slideways. A following pin attached to a common slide with the cutting tool, follows a master component or flat plate profile, the slide is traversed by pulley-cable or chain drive. These systems often become clogged and cutter movement is impaired.

Lack of 'Feel' due to pressures required to contact the following pin against the pattern proves a major problem together with encountering the various 'grain' directions with a common cutting direction of the tool, and the inability to recut any 'facet' of the work due to damage, or splitting, without an additional full length pass of the cutting tool, proves time consuming.

According to the present invention there is provided a compound pantograph arm system, comprising a tool holder and following pin mounted on a space frame.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows the copy attachment simply mounted on the bed of a woodturning lathe; Figure 2 illustrates the plan view of the space frame mounted over the lathe bed rails with the pantograph arm in the mid position; Figure 3 indicates the forward, backward, and 'arc' travel of the pantograph arm.

Referring to the drawing the pantograph copy attachment comprises a space frame (K) which can be mounted to various types of lathe bed i.e. single round bar double round bar double rectangular rail Supporting legs are also provided.

The main tool holding beam (P) is designed to slide easily over the space frame rails and is tethered in position by pivots (E) See Fig. 3 arc travel.

The dual arms (L) are pivoted on the sliding holder (F) which can be moved along the space frame rails to position the pantograph arm in the.most desirable position and locked.

The tool holder mounted on a pivot pin (N) pivots on the tool holder beam and is maintained in a constant 900 across the bed position by means of the control arms (X) (Y) and the quadrant (M).

The following pin(B) is adjusted by the leadscrew rod (I) to shorten or lengthen its position with the cutting tool (A) thereby decreasing or increasing cuts.

The workpiece is mounted in its normal position between centres (CC) and the master pattern (turned sample) is mounted directly behind and in easy eye line between centres (DD) The pantograph arm is operated by holding the knob (I) which makes adjustments to the depth of cut required, and traversing the following 'pin' along the master pattern in any direction, left to right or right to left and from top bottom of various contours of the pattern depending upon wood grain direction.

Deep grooves can be turned in this manner without traversing the pantograph arm to the full extent of the pattern for each cutting pass.

The pantograph arm and cutting tool can be pulled out and inserted into the workpiece at will, thereby enabling the operator to 'work' the workpiece with a creative feel.

A three position turret tooiholder is also used to give a choice of roughing or finishing tools.

The complete pantograph and tool holder assembly can be lifted off or parked at the rear of the space frame when not in use, normal turning can then take place without removal of the space frame from the lathe.

1. A pantograph arm copy attachment comprising a space frame secured to the lathe bed supporting a compound pantograph arm on which is mounted a following pin and cutting tool with provision for mounting a master pattern between fixed centres.

2. A pantograph arm copy attachment as claimed in Claim 1 wherein a space frame is mounted over any lathe bed whatever shape to spread the cutting loads and maintain flat and parallel surface for the tool holder beam to slide during wood turning.

3. A pantograph arm copy attachment as claimed in Claim 1 or Claim 2 wherein the pantograph arm moves in forward, backward and arc position freely and without directioned bias when moved by the operator.

4. A pantograph arm copy attachment as claimed in Claim 1 or Claim 2 or Claim 3 wherein it positions the following pin and cutting tool in the correct relationship to reproduce work from the pattern.

5. A pantograph arm copy attachment is claimed in Claim 1 or Claim 2 or Claim 3 or Claim 4 features cone nut and cup pivot points to eliminate pivot slack and maintain accuracy in adverse working conditions.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Pantograph copy attachment for woodturning lathes This invention relates to a copy attachment for woodturning lathes. Copy attachments are well known in their ability to assist the wood turner to reproduce turned items between centres, more easily and more accurately, reducing the need for individual measurement of each component. Copy attachments have taken various forms throughout the years but most which are used by the amateur hobbist, or the small time professional take the form of a single point cutting tool traversed over the machine bed length and guided by rollers or slideways. A following pin attached to a common slide with the cutting tool, follows a master component or flat plate profile, the slide is traversed by pulley-cable or chain drive. These systems often become clogged and cutter movement is impaired. Lack of 'Feel' due to pressures required to contact the following pin against the pattern proves a major problem together with encountering the various 'grain' directions with a common cutting direction of the tool, and the inability to recut any 'facet' of the work due to damage, or splitting, without an additional full length pass of the cutting tool, proves time consuming. According to the present invention there is provided a compound pantograph arm system, comprising a tool holder and following pin mounted on a space frame. A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 shows the copy attachment simply mounted on the bed of a woodturning lathe; Figure 2 illustrates the plan view of the space frame mounted over the lathe bed rails with the pantograph arm in the mid position; Figure 3 indicates the forward, backward, and 'arc' travel of the pantograph arm. Referring to the drawing the pantograph copy attachment comprises a space frame (K) which can be mounted to various types of lathe bed i.e. single round bar double round bar double rectangular rail Supporting legs are also provided. The main tool holding beam (P) is designed to slide easily over the space frame rails and is tethered in position by pivots (E) See Fig. 3 arc travel. The dual arms (L) are pivoted on the sliding holder (F) which can be moved along the space frame rails to position the pantograph arm in the.most desirable position and locked. The tool holder mounted on a pivot pin (N) pivots on the tool holder beam and is maintained in a constant 900 across the bed position by means of the control arms (X) (Y) and the quadrant (M). The following pin(B) is adjusted by the leadscrew rod (I) to shorten or lengthen its position with the cutting tool (A) thereby decreasing or increasing cuts. The workpiece is mounted in its normal position between centres (CC) and the master pattern (turned sample) is mounted directly behind and in easy eye line between centres (DD) The pantograph arm is operated by holding the knob (I) which makes adjustments to the depth of cut required, and traversing the following 'pin' along the master pattern in any direction, left to right or right to left and from top bottom of various contours of the pattern depending upon wood grain direction. Deep grooves can be turned in this manner without traversing the pantograph arm to the full extent of the pattern for each cutting pass. The pantograph arm and cutting tool can be pulled out and inserted into the workpiece at will, thereby enabling the operator to 'work' the workpiece with a creative feel. A three position turret tooiholder is also used to give a choice of roughing or finishing tools. The complete pantograph and tool holder assembly can be lifted off or parked at the rear of the space frame when not in use, normal turning can then take place without removal of the space frame from the lathe. CLAIMS

6. A pantograph arm copy attachment is claimed to feature a three position Turret toolholder to house roughing or finishing tools.

7. A pantograph arm and tool holder assembly can be removed or parked at the rear of the space frame when not in use.