NZ543258A

NZ543258A - Wood cutting tool

Info

Publication number: NZ543258A
Application number: NZ54325805A
Authority: NZ
Inventors: Pietro Finocchiaro
Original assignee: Pietro Finocchiaro
Priority date: 2005-02-25
Filing date: 2005-10-26
Publication date: 2006-07-28

Abstract

A cutting tool for use with a lathe tp make a bowl shaped article from a work piece during a cutting operation, the cutting tool including a blade and a blade supporting means which has a region which is in contact with said blade and the region including a friction reducing means for reducing the frictional force experienced by the blade at the blade supporting means during the cutting operation

Description

<div class="application article clearfix" id="description"> 10 1 WOOD CUTTING TOOL TECHNICAL FIELD This invention relates to an apparatus for forming bowls, in particular to cutting wooden bowls from a work-piece by means of a lathe. BACKGROUND OF THE INVENTION Wooden bowls can be cut or cored from a single block of wood using a lathe. The block of wood is referred to as a work-piece and generally the bowls are cut out of the work-piece by using a curved cutting tool such as a blade. The lathe typically includes a flat horizontal surface with tool rest for supporting a curved cutting tool. The cutting tool may be manually advanced towards a work-piece. If the work-piece is spinning at a sufficient speed, applying the cutting tool to the work-piece will cut out the interior of the work-piece leaving behind a bowl. Several bowls can be cut from one work-piece depending upon the thickness and profile of the bowls that are required. A problem with present bowl cutting apparatus is that during the cutting operation the blade is subjected to a large amount of frictional force caused by the resistance of the work-piece which is spinning at high speeds. This can result in the blade becoming jammed and unable to be advanced or retracted into or from the work-piece. If binding occurs then the lathe must be turned off and the blade must be withdrawn carefully to clear the bind. The problem of binding the knife can occur frequently when the blade is inserted by hand. The blade may not be properly stabilised or may move erratically when it cuts into the work-piece which is spinning at high speeds. A blade which is inserted by hand also requires the application of continual Intellectual Propofcj Office of N.Z. -1 MaS 2008 2 and consistent pressure which can be difficult to maintain over extended periods of time. 15 ® 20 A significant amount of pressure is required to insert the blade into the spinning work-piece, which means that only softer woods e.g. pine or cedar can be cut into bowl-shaped articles. It is a problem that these soft wooden bowls can dry and crack over time. A further problem with present bowl cutting apparatus is that the angle and speed of the cut into the work-piece can be difficult to control. If the angle of entry is wrong then the interior of the bowl will be too shallow or too deep. It is also possible that the wrong cutting angle will result in the walls of the bowl being cut too thin or too thick. If wood is damaged or cut incorrectly it can become expensive to replace the work-piece. In addition, in the present arrangements of bowl cutting apparatus once the cutting of the bowl is complete, the cored piece of wood is still attached to the work-piece. The core must remain attached otherwise it would spin away from the lathe given that the work-piece is spinning at high speeds. The core must be removed manually by the operator once the lathe is switched off, by using a lever or mallet to snap the core away which increases the risk of damage to the bowl-shaped article. Accordingly there is a need for an improved bowl cutting apparatus for cutting bowls using a lathe. It is an object of the present invention to reduce or eliminate at least one of the disadvantages of bowl cutting discussed above, or to at least provide a useful alternative. Irrteltoetu;;] ? Offioa ef 15 O 20 3 SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a cutting tool for use with a lathe to make a bowl shaped article from a work-piece during a cutting operation, the cutting tool including: the blade supporting means has a region, which in use is in contact with said blade, said region including a friction reducing means for reducing the frictional force experienced by the blade at the blade supporting means during the cutting operation. Preferably, the friction reducing means is a roller bearer. Preferably, in use, the blade bears on the roller bearer, the roller bearer thereby able to rotate to reduce frictional force experienced by the blade at the support means, allowing the blade to continue to advance or retract. Preferably, the blade is substantially curved in a lengthwise direction. Preferably, the blade supporting means is a blade housing which is able to sheath at least a portion of the blade. Preferably, the blade housing holds a substantial portion of top and bottom edges of the blade. Preferably, the blade housing has a top section and a bottom section each having a groove therein, into which the top edge and the bottom edge of the blade can be fitted, the grooves thereby acting as guides through which the a blade; and a blade supporting means; wherein blade can be advanced or retracted. Intellectual rc r;o; iy Office oi W.Z. 4 Preferably, the blade can protrude from the blade housing while still being held along the top and bottom edges of the blade by the top and bottom section grooves in the blade housing. 5 Preferably, the bottom section groove, past which the blade protrudes is terminated by the roller bearer. Preferably, the roller bearer at least partially lifts the blade from the bottom 10 section groove. Preferably, the blade can be advanced or retracted towards or from the work-piece by a blade moving means. 15 Preferably, the blade can be extended far enough into the work-piece so that the core of the work-piece is cut away completely from the work-piece. Preferably in use, the work-piece is held in position by the cutting tool by means of a tailstock. ® 20 Preferably in use, the tailstock can be adjusted so as to be fitted into the centre of the work-piece. Preferably, the tailstock and the blade, when advanced, act to hold the core of 25 the work-piece. BRIEF DESCRIPTION OF THE DRAWINGS ■1 "Op&i'Jy Office of m.z. — 3 P'" "5 1 iCJltO 5 15 0 20 The invention will now be described in more detail with reference to the following Figures in which: Figure 1 is a perspective view of the cutting tool of the present invention in use in cutting a work-piece on a lathe; Figure 2a is a top view of the cutting tool of Figure 1 showing the core of the work-piece held by the blade and the tailstock; Figure 2b is a perspective view of the cutting tool of Figure 1 showing the core of the work-piece having been removed from the work-piece while held by the blade and the tailstock; Figure 2c is a top view of the cutting tool of Figure 1 showing the core of the work-piece having been removed from the work-piece while held by the blade and the tailstock; Figure 3 is a different perspective view of the cutting tool of Figure 1 with the blade removed; and Figure 4 is a close up view of the blade in the cutting tool of Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Figure 1 shows the cutting tool 10, supported by a base, in position on a lathe (not shown). Cutting tool 10 includes blade 28, blade housing 32 and blade moving means 33. Once in position, cutting tool 10 can be used to cut a bowl-shaped article from a work-piece 14. Work-piece 14 is secured to the lathe (not shown) by a base plate 16 that is affixed to the base of work-piece 14 and then screwed onto a complementary screw connection on the lathe as would be understood by the person skilled in the art. The height of cutting tool 10 is adjusted by varying the length of the cutting tool legs 18. In the preferred embodiment legs 18 are threaded rods and the 6 correct height is achieved by adjusting and tightening connecting bolts around the thread. It will be appreciated, however, that any means of adjusting the height of the cutting tool could be used, for example, telescopic legs. The height of cutting tool 10 is adjusted until the tailstock 20 is in line 5 with the block 21 in the centre of work-piece 14. The distance of cutting tool 10 from work-piece 14 can be altered by sliding cutting tool 10 along the lathe towards, or away from, work-piece 14. The closer cutting tool 10 is to work-piece 14 the larger the bowl that is cut. The 10 further cutting tool 10 is from work-piece 14, the shallower and smaller the bowl that is cut. Once in the desired position the cutting tool 10 is clamped to the base of the lathe by clamps 22a and 22b. Any other means of securing the cutting tool in position would be suitable e.g. screws. 15 Tailstock 20 is advanced towards or retracted from work-piece 14 by turning a tailstock adjusting handle 24 that is connected to tailstock 20 by a threaded rod, (the threaded rod connection is underneath the cutting tool and cannot be seen in Figure 1). The distance of tailstock 20 from work-piece 14 can be adjusted until tailstock 20 can be fitted into block 21 in the centre of work-20 piece 14. Block 21 is cut using a known method by a known lathe tool and can be on the flat face of a new work-piece 14 or may be on the inside of a previously cut work-piece. Once tailstock 20 is in place cutting tool 10 is ready to be used. 25 An advantage of the present arrangement is that once cutting tool 10 is in position, the angle and position of cut 26 made by blade 28 cannot change before, during, or after the cutting operation, since blade 28 is held in position (discussed further below). Intstacifuyi Property Office ot SV.Z. -1 MA."? 2008 7 In use, work-piece 14 is spun at a speed chosen with respect to the type of wood being cut. The speed is chosen by the person skilled in the art depending upon the moisture content of the wood, the direction of the grain, the length of the wood fibres and the power of the lathe. The work-piece 14 5 spins in the anticlockwise direction and blade 28 is positioned to the left side of work-piece 14. The cutting portion of blade 28 is therefore along the top edge of blade 28 so that it cuts against the force of the spinning work-piece 14. If work-piece 14 were spun in the clock-wise direction then the position of blade 28 would alter so that the cutting portion of blade 28 would still cut 10 against the force of the spinning work-piece 14. For example, if the work-piece were spinning in the clockwise direction, blade 28 would be positioned to the right side of work-piece 14, or the cutting portion of blade 28 would be on the underside of blade 28. 15 During the cutting operation, blade 28 is advanced towards work-piece 14 by an operator (not shown) turning handle 33 of a blade moving means having arms 30a and 30b which are connected to the rear of blade 28 and a threaded rod 31. The arms 30a and 30b are moved up and down the threaded rod 31 by turning handle 33, which in turn moves blade 28 into and out of the blade 20 housing 32. Blade 28 can be fully retracted into blade housing 32 or fully advanced from blade housing 32. It should be understood that any suitable mechanism for advancing and retracting blade 28 could be used, for example, blade 28 could be moved by gears or the blade moving mechanism could be actuated by electronic means. 25 The depth of blade 28 can be carefully controlled by turning handle 33 to draw arms 30a and 30b along threaded rod 31. The present arrangement means that the force applied to blade 28 by the blade moving mechanism is continuous and consistent. Furthermore, blade 28 will remain in position once iriio'lc-'t.-;' Oi'iii.'ii ol i'j.z. -1 i2sos d tr r- , \/ c n 8 it has been advanced or retracted a certain distance, even if there is no pressure applied to handle 33. The advantage of this is that blade 28 will remain stable and in place even if the operator is distracted or pauses during the cutting operation. This reduces the likelihood of blade 28 being ejected 5 from work-piece 14 in an uncontrolled manner, which can be dangerous to those around the lathe and, furthermore, reduces the likelihood of damage to work-piece 14. A further advantage of using the present blade moving mechanism is that the 10 force required to be applied by the operator to cut into the work-piece 14 is substantially reduced compared with prior arrangements. The reduction of the force required to cut into the work-piece 14 means that harder woods, e.g teak or rosewood, can be more easily cut by the present arrangement of cutting tool 10. Prior arrangements required the application of great force by 15 the operator to cut the work-piece and generally only softer woods were suitable for cutting. These soft woods are prone to drying and cracking over time when formed into bowl shaped articles. Blade 28 is continually advanced into work-piece 14 until the core of the bowl-20 shaped article is completely cut from work-piece 14. Once the bowl shaped article is completely cut, cutting tool 10 is moved away from work-piece 14. The advanced blade 28 and tailstock 20 act to hold the core 35 of work-piece 14 securely in position. The advantage of this arrangement is that the operator does not need to manually remove the core from the work-piece using a lever 25 or a mallet as is the case in prior arrangements, the risk of damage to the bowl-shaped article is therefore reduced. Figure 2a is a top view of cutting tool 10 and work-piece 14 along plane A and A' as indicated in Figure 1. Blade 28 (shown as a dotted line) is fully advanced Ofi'Gu o: t^.Z. ft t » Ci. c i St ib into work-piece 14 and the core 35 of work-piece 14 is ready to be removed. Figure 2b shows core 35 upon removal, the bowl-shaped article cut from work-piece 14 can be seen. Blade 28 (shown as dotted lines) and tailstock 20 hold the core in place until it can be safely removed by the operator. Figure 2c 5 is a top view of Figure 2b more clearly showing how core 35 is held in place by blade 28 and tailstock 20. The added advantage of this arrangement, in addition to safe removal of core 35, is that the core 35 of work-piece 14 is held securely at all times and is not able to spin away in an uncontrolled manner once it is cut from work-piece 14, which could be dangerous to those around 10 the lathe. Figure 3 is an alternative view of cutting tool 10 of Figure 1 with blade 28 removed. The blade housing 32 has a top section 32a and a bottom section 32b. Blade housing 32 is used to support the blade 28 (not shown in this 15 Figure) by means of grooves 34a and 34b disposed in the top and bottom sections 32a and 32b of blade housing 32. The grooves are rectangular cuts into top (32a) and bottom sections (32b) of blade housing 32, however, any suitable means of supporting the blade could be used, for example, guide rails or other shaped cuts. 20 The skilled person will understand that in this embodiment the bottom section 32a of blade housing 32 acts as a base having legs 18, however, blade housing 32 could be supported by any suitable means. For example the blade housing could be supported by a pole or it could be supported from above 25 thereby being suspended in position on the lathe. It is an option that blade housing 32 only sheath a part of blade 28. Blade housing 32 could be positioned such that blade 28 passes through blade Office ot N.2. -1 K;,3 2C0S RECEIVE 10 housing 32 just prior to cutting work-piece 14. In this arrangement blade 28 is still supported by blade housing 32 prior to the cutting operation. It can be seen in Figure 3 that blade housing 32 is hemispherical in shape in 5 order that blade housing 32 can accommodate the blade 28 which is curved in the lengthwise direction. An advantage of the present arrangement is that once cutting tool 10 is in position, the angle and position of cut 26 made by blade 28 cannot change since blade 28 is supported in position by blade housing 32. The shape of the bowl-shaped article that is cut can therefore be 10 accurately predetermined and it is less likely that the bowl will be too shallow, too deep or have walls that are too thick or too thin. Using the present arrangement it is also less likely that cut 26 will be cut awkwardly or that the blade will move erratically, thereby blade 28 is less likely to bind in cut 26. In addition, blade housing 32 provides support to blade 28 at the top, 15 bottom and sides, to increase the stability of blade 28. Bottom section 32b of blade housing 32 has a roller bearer 36 at the terminus of groove 34b in bottom section 32b. Blade 28 (not shown) has been omitted from Figure 3 in order that the position of roller bearer 36 can be clearly 20 viewed. Roller bearer 36 is affixed by a rod 37 which is in turn bolted to the underside of bottom section 32b of blade housing 32. Figure 4 is a close up view of blade 28 in blade housing 32. Blade 28 can be advanced from blade housing 32 in the direction indicated by arrow 40, or 25 retracted into blade housing 32 in the direction indicated by arrow 42. It is preferred that blade 28 is advanced or retracted by means of the blade moving means discussed above. In Figure 4 blade 28 is shown in one possible advanced position. Office of i'-j.ii. RECESV £D 11 It should be understood from Figure 4 that as blade 28 advances from blade housing 32, blade 28 is held along its top edge by groove 34a and along its bottom edge by groove 34b. Blade 28 is also supported along a part of the bottom edge by roller bearer 36. Blade 28 bears down onto roller bearer 36, 5 roller bearer 36 acting to slightly lift blade 28 out of groove 34b. When blade 28 cuts into work-piece 14 there is a significant amount of downwards pressure exerted on blade 28 because work-piece 14 is spinning in an anticlockwise direction and, in this case, blade 28 is located on the leftside of work-piece 14. The resulting frictional force can result in the blade becoming stuck in blade housing 32 and unable to be advanced or retracted without turning off the lathe. To counteract this, roller bearer 36 acts to reduce the frictional force experienced by blade 28 during the cutting operation by lifting blade 28 slightly above the floor of groove 34a allowing the main point of contact between the blade 28 and the support (roller bearer 36) to be able to roll forward, thereby continually allowing blade 28 to advance or retract, despite the downwardly bearing pressure induced by work-piece 14. If work-piece 14 were to spin in the clockwise direction and blade 28 were still disposed on the left of work-piece 14, then the resulting force would act to force blade 28 upwards, into the top groove 34a of blade housing 32. In this case roller bearer 36 would be disposed above blade 28 to reduce the frictional force between blade 28 and the top section 32 of blade housing 32. 25 The skilled addressee will understand that any friction reducing means could be used in place of a roller bearer 36. For example, one or more ball bearings could be mounted at the terminus of groove 34b, or there could be a plurality of smaller rollers arranged in a suitable configuration. Alternatively, a lower-friction surface may be provided. Of M.2. - < a' 2005 ,-RE I ciVE D I 10 15 12 It will be understood that the above has been described with reference to a particular embodiment and that many variations and modifications may be made within the scope of the present invention. For example, a bowl could be cut from any suitably shaped work-piece, both of which can be mounted on any suitable lathe. The work-piece can be wood, however, any other suitable materials could be cut by the cutting tool, for example, stone or ivory. </div>

Claims

<div class="application article clearfix printTableText" id="claims"> 13 THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A cutting tool for use with a lathe to make a bowl shaped article from a work-piece during a cutting operation, the cutting tool including: a blade; and a blade supporting means; wherein the blade supporting means has a region, which in use is in contact with said blade, said region including a friction reducing means for reducing the frictional force experienced by the blade at the blade supporting means during the cutting operation.

2. A cutting tool according to claim 1 wherein the friction reducing means is a roller bearer.

3. A cutting tool according to claim 2 wherein in use, the blade bears on the roller bearer, the roller bearer thereby able to rotate to reduce frictional force experienced by the blade at the support means, allowing the blade to continue to advance or retract.

4. A cutting tool according to any one of claims 1 to 3 wherein the blade is substantially curved in a lengthwise direction.

5. A cutting tool according to any one of claims 1 to 4 wherein the blade supporting means is a blade housing which is able to sheath at least a portion of the blade.

6. A cutting tool according to claim 5 wherein the blade housing holds a substantial portion of top and bottom edges of the blade. 14

7. A cutting tool according to claim 5 or 6 wherein the blade housing has a top section and a bottom section each having a groove therein, into which the top edge and the bottom edge of the blade can be fitted, the grooves thereby acting as guides through which the blade can be advanced or retracted. 5

8. A cutting tool according to claim 7 wherein the blade can protrude from the blade housing while still being held along the top and bottom edges of the blade by the top and bottom section grooves in the blade housing. 10

9. A cutting tool according to claim 7 or 8, wherein the bottom section groove, past which the blade protrudes is terminated by the roller bearer.

10. A cutting tool according to claim 9 wherein in use, the roller bearer at least partially lifts the blade from the bottom section groove. 15

11. A cutting tool according to any one of claims 1 to 10 wherein the blade can be advanced or retracted towards or from the work-piece by a blade moving means. 20

12. A cutting tool according to any one of claims 1 to 11 wherein in use, the blade can be extended far enough into the work-piece so that the core of the work-piece is cut away completely from the work-piece.

13. A cutting tool according to any one of claims 1 to 12 wherein in use, the 25 work-piece is held in position by the cutting tool by means of a tailstock.

14. A cutting tool according to claim 13 wherein in use, the tailstock can be adjusted so as to be fitted into the centre of the work-piece. IriiSnoor.ui f- < or'-Qiij Office of Tm.Z. iw, /luuo REu 'c, \ v iui 15

15. A cutting tool according to claim 13 or 14 wherein the tailstock and the blade, when advanced, act to hold the core of the work-piece.

16. A cutting tool as claimed in any one of claims 1 to 15 substantially as herein described with reference to the accompanying drawings. Intsltectual Pr-.^ Office of b.Z. -1 wa 2CC3 R E C EIV ABSTRACT Disclosed is a cutting tool for cutting bowl-shaped articles from a work piece. The cutting tool provides a roller-bearer arrangement to reduce friction at the 5 blade, and a housing to provide additional support to the blade. The cutting tool can also securely hold the bowl-shaped article in place during and after cutting to reduce the risk of injury to the operator. </div>