CA1310497C - Apparatus for sharpening edge tools - Google Patents
Apparatus for sharpening edge toolsInfo
- Publication number
- CA1310497C CA1310497C CA 577975 CA577975A CA1310497C CA 1310497 C CA1310497 C CA 1310497C CA 577975 CA577975 CA 577975 CA 577975 A CA577975 A CA 577975A CA 1310497 C CA1310497 C CA 1310497C
- Authority
- CA
- Canada
- Prior art keywords
- tool
- edge
- axis
- grinding stone
- mount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
Abstract
ABSTRACT OF THE INVENTION
Apparatus for sharpening an edge tool having a linear cutting edge, such as a chisel, plane iron or gouge, comprises a rotary grindstone having a cylindrically curved surface mounted for rotation about an axis coincident with the axis of the cylinder, and tool mounting means on which an edge tool to be sharpened can be located, the tool mounting means including guide means orientated such that relative movement between the tool and the rotary grindstone can take place substantially perpendicular to the plane including the point of contact between the edge tool and the stone and the axis of the grindstone. The tool mounting means includes a tool mount turnable about an axis orthogonal to the plane of a tool carried thereby, which is itself carried on a tool mount carrier turnable about an axis parallel to the axis of the rotary grindstone so that a tool to be sharpened can be positioned with its edge inclined to the axis of the grindstone but lying in a plane parallel to this axis and to the line of relative displacement between the tool mounting means and the grindstone.
Apparatus for sharpening an edge tool having a linear cutting edge, such as a chisel, plane iron or gouge, comprises a rotary grindstone having a cylindrically curved surface mounted for rotation about an axis coincident with the axis of the cylinder, and tool mounting means on which an edge tool to be sharpened can be located, the tool mounting means including guide means orientated such that relative movement between the tool and the rotary grindstone can take place substantially perpendicular to the plane including the point of contact between the edge tool and the stone and the axis of the grindstone. The tool mounting means includes a tool mount turnable about an axis orthogonal to the plane of a tool carried thereby, which is itself carried on a tool mount carrier turnable about an axis parallel to the axis of the rotary grindstone so that a tool to be sharpened can be positioned with its edge inclined to the axis of the grindstone but lying in a plane parallel to this axis and to the line of relative displacement between the tool mounting means and the grindstone.
Description
~31~97 1 BACKGROUND OF T~E_INVENTION
4 It is well known that edge tools must be maintained in perfect condition in order to work satisfactorily, and 6 although it is well realised that blunt tools are the 7 cause of many accidents because they do not cut freely 8 and properly, the sharpening of edge tools is 9 nevertheless often neglected because of the high degree of skill involved in correctly performing this task~
11 ~ecently, sharpening guides have become available, which 12 hold the edge tool in a fixed orientation allowing it to 13 be moved over a stationary stone to grind it to a correct 14 shape, but such grinding operation is still laborious and ~ime consuming. Edge tools having curved edyes, such as 16 gouges, are almost impossible for the amateur to sharpen 17 properly.. Hand-held edge tools are usually supplied by 18 the manufacturer with the edge sharpened by grinding a 19 flat bevel facet at 25 to the opposite major face of the tool, with the very edge of the tool being honed at 30 21 on a finer stone. Although large scale aut~omatic 22 machinery for grinding the bevel facet and honing the 23 edge of a hand tool are known, equipment available for 24 the owner of a set of hand tools to sharpen these is limited to two basic type the first of which is a guide 26 for use.on a stationary flat stone, which is both slow : . ' .
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~3~0~97 1 and subject to wear and the second of which is typi~ally
4 It is well known that edge tools must be maintained in perfect condition in order to work satisfactorily, and 6 although it is well realised that blunt tools are the 7 cause of many accidents because they do not cut freely 8 and properly, the sharpening of edge tools is 9 nevertheless often neglected because of the high degree of skill involved in correctly performing this task~
11 ~ecently, sharpening guides have become available, which 12 hold the edge tool in a fixed orientation allowing it to 13 be moved over a stationary stone to grind it to a correct 14 shape, but such grinding operation is still laborious and ~ime consuming. Edge tools having curved edyes, such as 16 gouges, are almost impossible for the amateur to sharpen 17 properly.. Hand-held edge tools are usually supplied by 18 the manufacturer with the edge sharpened by grinding a 19 flat bevel facet at 25 to the opposite major face of the tool, with the very edge of the tool being honed at 30 21 on a finer stone. Although large scale aut~omatic 22 machinery for grinding the bevel facet and honing the 23 edge of a hand tool are known, equipment available for 24 the owner of a set of hand tools to sharpen these is limited to two basic type the first of which is a guide 26 for use.on a stationary flat stone, which is both slow : . ' .
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~3~0~97 1 and subject to wear and the second of which is typi~ally
2 shown in British Patent No 1293729, which des~ribes a
3 pair of rotary grindstones one at each end o~ a motor
4 shaft in a configuration similar to a conventional bench ; 5 grinder, in front of which is positioned a tool mount ' 6 carried on a transverse guide bar extending parallel to 7 the axis of rotation of the grindstones. An edge tool 8 fitted on the mount can then be displaced across the g cylindrical surface of one or other of the rotary grindstones and held rigidly in a predetermined 11 orientation whilst being ground. This known tool has the 12 disadvantage that, because it is passed over the 13 cylindrical surface of the grindstone the facet ground on 14 the bevel edge of the tool is concavely curved to form a so-called hollow ground face, which weakens the very edge 16 o~ the tool and allows it to become blunt more rapidly 17 than a ~lat edge. There is also the possibility that a 18 variation in pressure applied by the user as the edge 19 tool is trayersed ~cross the grindstone will result in differing amounts of material being removed from the edge 21 of the tool at different transverse positions so that a 22 straight true edge is not guaranteed, especially for 23 wider tools such as plane irons. In an attempt to 24 overcome this problem the tool holder described in European Patent application 225806 incorporates a stop 26 member for limiting the rotation of a tool holder abou-t a .
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~3~97 1 tool guide formed as a c~lindrical bar, but this tool too 2 provides a bevel facet which is hollow ground and, 3 furthermore, involves considerably complexity in the tool 4 mount.
9 A previous object of the present invention is to provide a fast, efficient, accurate and simple apparatus for 11 sharpening an edge tool which is easy to use and which 12 has a wide range of.application.
13 : , 14 Another object of the present invention is to provide apparatus for sharpeni.ng an edge tool which is suitable 16 for both professional and ama-teur alike whilst being of 17 reasonable cost.
19 A further object of the present invention i~ to provide apparatus.for sharpening edge tools having both straight 2.1 and.curved cutting edges.
23 ..^ . . ..SUMMARY OF THE INVENTION
26 According to the present invention, there is provided 131 ~9P~
1 apparatus for sharpening an edge tool having a llnear 2 cutting edge, such as a chisel, a plane iron or a gouge, 3 com~rising a rotary grinding stone having a cylindrically 4 curved surface mounted for rotation about an axis coincident with the axis of the cylinder and tool 6 mounting means on which an edge tool to be sharpened can 7 be located, the tool mounting means including guide means 8 oriented such that relative movement between the tool and 9 the rotary grinding stor,e can take place substantially perpendicular to the plane including the point of contact 11 between the edge tool and the stone and the axis of the 12 grindstone.
13 .i~ ' 14 By providing this arrangement, in which the relative movement of the stone and the tool being sharpened is 16 orthogonally located with respect to that employed in 17 known tool sharpening machines it is possible to make use 18 of a relative.ly small stone whilst nevertheless.being 1~ able to sharpen edge tools such as chisels and plane irons the length of the cutting edges o~ which are very 21 substantially different from one another.
23 Preferably the tool mounting means of the present 24 apparatùs includes means for retaining an edge tool in a selectable de,termined orientation with respect to,the 26 axis of roTtation of the rotary grinding stone. This . . ~ , ~310~97 1 enables not only the honed edye, but also a relief angle 2 to be ground on a tool. It is known, for example, that 3 chisels are usually ground to an angle of 25 to the 4 plane of the flat face of the tool, with a narrow strip along the cutting edge being honed to an angle in the 6 region of 30. The apparatus of the present invention 7 makes it possible for both ground faces to be formed 8 easily and quickly.
Preferably the tool mounting means is adjustable such 11 that the inclination oE the edge of an edge tool to be 12 sharpened with respect to the line of relative,movement 13 between the tool mounting means and the rotary grindstone 14 is adjustable over a range of inclination with ,the~said edge lying in a plane parallel to both the axis of 16 rotation of the grindstone and the line of relative 17 movement between the tool mounting means and the 18 grindstone.
The tool mounting means pre~erably include a tool mount 21 which can be ,fit~ted to an underlying support in one of 22 two pre-determined.orientations whereby to select one of 23 two angles at,wh,ich the edge of the tool is to be ground.
24 Thi3 adjustment can also be used, as will be explained in more detail ,be.low, to select when an internal,or external 26 edge is formed on a curved tool such as a gouge. It will lC~04s7 1 be appreciated tha-t gouges are formed in two types, bo~h 2 having basically a cylindrically curved steel body, but 3 one type having a bevel edge cut on the convex or outer 4 face at the end of the body whilst the other type has a bevel edge Eormed on th0 concave or inner face thereof.
6 Such gouges are used for cutting internal and external 7 curves respectively, for example when producing parallel 8 flutes or other decorative work.
The path of relative movemellt between the edge tool to be 11 sharpened and the rotary grinding stone may be 12 substantially~rectilinea~, as in the case of chisels and 13 plane irons, but may be made curvilinear by adaptation 14 using an adapter to allow sharpening of curved-edge tools, such as gouges.
17 Different embodiments of the invention may be provided 18 with different arrangements for driving the rotary 19 movement of the stone. For example, the rotary grindstone may be mounted on bearings fixedly located 21 within a casing of the apparatus and the relative 22 movement between the tool to be sharpened and the rotary 23 grindstone effected by displacement of the tool alon~ a 24 determined path with respec-t to the casing and thus with respect to the;rotary grindstone. Alternatively, 26 however, the tool could be held stationary on the casing ,.
,' ' ~10~97 1 and the stone arranged to be movable with respect 2 thereto, such movement being effected by lateral 3 translation o~ the stone spindle p~rpendicular -to its 4 length. Such movemen-t would necessarily need to be linear or curved in a plane including the line of the 6 cutting edge (in the case of a rectilinear cutting edge) 7 or curved to match the curve of the cutting edge (in the 8 case of a curvilinear cutting edge).
The rotary grindstone is conveniently mounted on a 11 spindle of a spindle assembly driven by a motor carried 12 within the casing of the apparatus, and the motor may be 13 fixedly located or mounted so as to be movable with the 14 stone. Alternatively, the rotary grindstone may be mounted on a freely rotatable spindle assembly having an 16 input end ~hich projects from the casing of the apparatus 17 for atta~hment to a removably attachable drive motor such 18 as a hand held pistol drill.
To achieve this end the spindle assembly preferably 21 incudes a grindstone spindle on which the r~tary 22 grindstone is mounted, a drive input spindle lying at an 23 angle to the grindstone spindle, and a bevel gear 24 transmission linking the two for transmission of rotary motion from the drive input spindle to the grindstone 26 spindle. To simplify manufacturing processes this . / , . , - .
~310497 , g 1 arrangement can also be used in embodiments having an 2 integral ~otor, with the bevel gear being turned through 3 90 such that the input shaft lies parallel to the casing 4 wall rather than perpendicular thereto as in the case of ; 5 the embodiment intended for connection to an external ;~` 6 motor.
8 The tool mounting means of the apparatus of the present 9 lnvention may comprise a tool mount turnable about an axis perpendicular to the plane of a tool mount face 11 thereof and a tool mount carrier turnable about an axis 12 parallel,.~to the axis of the grindstone. In suchjan 13 arrangement it is.possible that the tool mount and tool 14 mount carrier are interconnected so that ar.gular displacement of~the tool mount carrier about its axis is 16 associated with related angular displacement of:the~tool 17 mount about its axis with respect to the tool mount 18 carrier in such a way that one edge of the t~ol mount 19 always lies in a plane parallel to both the axis of rotation of the grindstone and the line of displacement 21 of the tool mount assembly along the rectilinear guide 22 meaps.. .. ..
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24 The tool mountin.g means may include a support b,ody ~, displaceable parallel to the said guide and a tool 26 carrier which,is displaceable with respect to the.support .
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' 1 body in a direction perpendicular to the rectilinear 2 guide. The tool carrier may itself likewise be formed in 3 two parts, a first part permanently fitted to the support 4 body and displaceable with respect thereto as a carriage in the said perpendicular direction, and a second part or 6 tool mount removably attachable to the carriage and 7 interchangeable with similar such -tool mounts adapted for 8 receiving different tools to be sharpened.
In a preferred embodiment of the present invention the 11 said rectilinear guide means is formed as a pair of 12 parallel rods mounted fixedly on -the casing with a 13 pre-determined spacing therebetween, and the support body 14 is slidable therealong. Such sliding contact may be provided by means of plain bearings, or by rolling 16 element bearings in a backlash-free configuration, such 17 as a recirculating ball bearing. Alternatively, the 18 rectilinear guide may be in the form of a V-block 19 receiving contact members of an appropriate carriage.
21 The~rectilinear guide means may include means for varying 22 the inc~lination of a tool mount about an axis parallel to 23 the length of the recti]inear guide means whereby to 24 adjust the angle at which a bevel facet at the edge of the tool is ground.
`` 1310497 1 Preferably the said support body is formed with or 2 carries rectilinear yuide means for the tool carrier to 3 guide the said tool carrier in the said perpendicular 4 direction to advance a tool carried thereby towards a line of intersection with the grindstone whereby to 6 determine the amount of material removed in a pass of the 7 tool and grindstone upon relative movement therebetween.
8 The said support body and the tool carrier are 9 conveniently interlinked by screw threaded motion control means operable to cause such relative movement between 11 them with a controllable fine adjustment of the relative 12 positions thereof whereby to set the amount of material 13 removed from the tool in such a pass between the tool 14 mounting means and the ~rindstone upon relative movement between them.
18 The interconnection between the tool mount and the 19 carriage of the tool carrier may be iormed, as in the preferred embodiment, by means of a projection on the or 21 each tool mount, which projection has a dovetail 22 cross-section~which can be introduced into a groove of 23 complementary.,dovetail cross-section in the said !
24 carriage. One of these two preferably has clamping means for securing them toge-ther when the dovetail proj,ection 26 has been fitted into the dovetail groove.
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310~97 2 Different tool mounts may be shaped specifically to 3 receive different kinds of tools. For example, the tool ~ mount may have at least one substantially flat face for locating ~ corresponding:ly flat face of a tool to be 6 sharpened. This flat face may be inclined with respect 7 to the dovetail projection and there may be provided a 8 second dovetail projection at a different angle from that 9 of the first so that the inclined face can be presented in one of two inclinations whereby to offer the edge tool 11 at one or the other of two different inclinations to the 12 grindstone. For a different tool, such as gouge, the 13 tool mount may have a convexly curved bicuspid curvature 14 to receive a cylindrically curved surface of a tool to be sharpened, allowing relative movement thereof with 16 respect to the said tool carrier about an axis coincident 17 with.that of the said cylindrically curved surface..of the 18 tool to be sharpened.
19 ~ . : . ;.
Whatever the form of the tool mount there are preferably 21 provided retainer means for retaining a tool to be 22 sharpened with a face thereof in contact with a face of 23 the tool mount. Such re~ainer means may comprise an arm 24 projecting from the tool moun-t with a lateral finger pro~ecting therefrom whereby partly to encircle the tool 26 to be sharpened and draw it into contact with the said ; . -. 1. . ' -.. ..
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- 1310~97 .
1 one face of the tool mount. Other forms of retainer may, 2 alternatively, be employed.
4 As an addition, the casing may further include a housing for a substantially flat stationary grindstone against 6 which a tool can be worked for cleaning of any burrs 7 producsd by the rotary grindstone in use of the 8 apparatus. The rotary grindstone is preferably made of 9 an abrasive laminate, and it has been found that a cloth/abrasive laminate is of particular utility.
11 Alternatively, however, often abrasive materials may be 12 employed, such~ as a plasma sprayed ceramic on a metal 13 base having a grit-blasted surface.
Other features and advantages of the present invention 16 will become appararent from a study of the following 17 detailed description in which reference is made to the 18 accompanying drawings, provided purely by way of 19 non-limitative example only.
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21 ~ i BR I EF DESCR I PT I ON OF THE DRAW I N~S , 23 ~ i 24 Figure 1 is a perspective view of the first embodiment of the invention seen from the front;
26 Figure 2 is a perspective view of the embodiment of 1~10~97 1 Figure 1 ~een from the rear;
2 Figurs 3 is an enlarged perspective view of the 3 tool mount of the embodiment of Figure 1;
4 Figur~ 4 is a cross-section through the tool mount taken on the line IV-IV of Figure 1;
' 6 Figure 5 is a perspective view o~ an alternative 7 tool mount different from that illustrated in Figures 3 8 and 4;
: 9 Figure 6 is a perspective view of a further alternative tool mount;
11 Figure 7 is a side view illustrating one way in `: 12 which.the toQl mount~of Figure 5 can be set up for 13 grinding an internal ly bevelled gouge; and 14 Figure 8 is a side view illustrating a second configuration,i~,which the tool mount of Figure.,5 c,an.be set for grinding an e~ternally bevelled gouge.
19 DESCRIPTION,OF THE PREFERRED EMBQDIMENTS
2~
22 The appar,at,us shown in Figure 1 of the drawings comp,rises 23 a,casing..ge,~!era;lly.,indicated 11 having a slide body part 24 12 and a ~.tone support part 13. The slide body part 12 has an inclined;upper,face 14 over which is positioned a 26 guide rail,,s,upport base 15 which i~ aarried at, each end :`
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~10497 1 by upwardly projecting lateral supports 16, 17 secured at 2 each end of the slide body part 12 of the casing. The 3 guide rail support base 15 is pivoted to turn about a 4 horizontal axis X-X which coincides with the pivotal attachment of the guide rail support base 15 to the 6 lateral supports 16 and 17, which is evidenced in Figures 7 1 and 2 by the attachment nut 18 which sacures a plVOt 8 19.
The lateral supports 16, 17 each have an arcuate slot 11 (not shown) through which passes a threaded pin attached 12 to the guidq rail support base 15 and on to which is 13 screwed a clamp wheel 20. A similar clamp wheel is~
14 positioned in~r.elation to the lateral support 1~, but is not visible in the drawings. -,.
17 At each end.of~the guide rail support.base 15 are two 18 guide rail support blocks 21, 22 in which are secured two 19 parallel guide rails 23, 24. On one of the guide rail support blocks, namely the block 21, there is marked a 21 scale of graduations generally indicated with the 22 reference numeral 25, which can be referenced against the 23 upper odge of the lateral support 16 to determine the 24 angul~r posi.ti~on of the plane defined by the t.wo guide rail~.~23, 24 in relation to the slide body part,12 o the 26 casing or reasons which will bq described in more detail .
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1310~1~7 belowO
' ~ 2 ` ~ 3 Slidably carried on the parallel rails 23, 24 is a tool 4 mount carriage generally indicated 26, which comprises a main carriage body 27 beneath which is secured a reaction 6 plate 28. The main c.arriage body 27 and the reaction ; 7 plate 28 have respective parallel part cylindrical 8 grooves in which the guide rails 23, 24 are received and 9 the reaction plate 28 is biased, with respect to the main carriage body 27 by means of a biasing spring 29 which 11 can be seen in Figure 4. Adjustment screws (not shown) : 12 determlne tho force applied between the reaction plate 28 1~ and the main carriage ~ody 27 so that the frictional 14 resistance ex~erienced by the tool mount carriage,26 as it is displaced along the guide rails 23, 24 can be 16 adju ted. Conveniently the main carriage body 27 and 17 reaction plate 28 are made from a plastics material 18 having a relatively low coefficient o friction,, whilst 19 the ~uide r,a,ils.23, 24 may be made from a metal or,other m:aterial-wh~ichlcan be highly polished so tha~;again~
21 there~is a,lowi,~rictional re~istance-between the rai.ls 22 and the tool.mount carriage as this is displaced to~and 23 fro.along th,s guide rails.
: 25 The main carriage body 27 has a recess 30 in its upper 26 face to form a guide for a transverse slide member 31 .
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13~0~97 : 1 which,~as can be seen in Figure 4, has a downwardly 2 pro~ecting threaded boss 32 engaged by a threaded shaft 3 33 on one end of which is a butterfly knob 34. The shaft 4 33 is threaded only along its intermediate section and has plain bearings 35, 36 at each end and is restrained 6 from axial movement by a washer 37 and lock pin 38 at one ~ 7 end, and by a pair o~ lock nuts 39, 40 at the other. By ; 8 turning the butterfly knob 34, therefore, linear 9 displacement of the transverse slide member 31 can be achieved in a direction transverse the length o the 11 guide rails 23, 24.
~ 12 ~ , : 13 In the upper::face.of the transverse slide member 31 is a 14 socket receivin~ a,stud 41 which is a tight fit therein and which may.be-secured in position,.for example by 16 : adhesives. The stud 41 serves as a locating peg and 17 pivot for a tool mount assembly generally indicated 42 ~ 18 and comprising a tool mount carrier 43 which has a 19 vertical rear face 44 and an inclined front face 45.
Piqotally mounted to the front face 45 of the tool mount 21 ca~rier 43 is the,tool mount itself, indicated with the : . .
22 ~qference numaral 46, which has a generally planar .
23 configuration and a central rearwardly projecting;spigot 24 47 received,i,n.,a,correspondingly shaped socket,48 in the inclined face,4.5 of the tool mount.c~rrier 43. Th,e tool 26 mount 46 has a ~lat front face 49 in which are housed two ..
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i310~97 1 permanent magnets 50, 51 for retaining a metal tool such 2 as a chi~el or plane iron in position when engagad 3 thereon. At one side of the tool mount 46 is an 4 upstanding shoulder 52 which serves as a locating abutment for one side of a tool 53 when positioned with 6 its major face flat against the flat front face 49 of the 7 tool mount 46, in which position it will be retained by 8 the permanent magnets 50 and 51.
The stone support part 13 of the casing carries a 11 vertical spindle (not shown) on the upper end of which is 12 secured a rotary grindstone 54 of the so-called "cup"
13 type having a central recess 55 in its upper circular 14 flat face through-which access can be gained to,a nut securing the.s.tone 54 on the upper end of the spindle.
16 For reasons which.will be explained in.more deta.il below 17 the æpind-le.itself may have an axial threaded hole,at one 18 end as well as an.externally threaded portion for 19 receiving the securing nut which retains the stone 54 in position. The stone support part 13 of the casing 11 21 includes a semi-cyllndrical shroud 56 which~encloses the 22 stone 54 over approximately one half o~ its circumference 23 and the shroud 56 is provided with a removable cover 57 24 carrying a stationary ~ine slip stone 58.
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26 In use,~f ~the embodiment desaribed above a tool s,uch as -- ; ; , . .
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1 the chisel 53 illustrated in broken outline in Figure 3, 2 is positioned on the flat front face 49 of the tool mount 3 46 so that its edge 59 is closely adjacent the ~ 4 cylindrical surface of the rotary grindstone 54. By : 5 turnin~ the tool mount 46 about the axis defined by the 6 s~igot 4? the ed~e 59 of the tool 53 can be incl ined so 7 that it occupies a vertical distance corresponding to the 8 axial dimenslon of the stone 54. However, since the axis 9 defined by the spigot 47 is inclined to the axis of rotation of the stone 54 this movement will, when viewed 11 in plan, leave the edge 59 of the tool at an inclination 12 to the line of travel of the tool mount carriage 26 on 13 the guide rails 23, 24 so that as the carriage 26 is 14 displaced to and fro along the guide rails 23, 24 only , ~` ~ 15 the proximal corner 60 of the edge 59 of the tool 53 will ` 1 b come inta contact with the grindstone 54. To compensate . ~
17. ~or this, there~orei the tool mount body is tur~ed,~about 18 tha ve~tical ~xi~ defined by the stud 41 until:the edge 19 59 is again parallel to the line defined by the guide rails 23" 24. The~e two movements may be made entirely 21 independently,~as in the embodiment illustr~ted, leaying ~2 the operator -to:~udge the precise position of the tool 23 mount carrier 43 and the tool mount 46 to establish the 24 correct alignmant of the edge 59 of the tool or, as illustrated in broken outline in Figure 4, a m~chanical 26 interlink may be provided, for example in the form of a :
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~310~7 : 1 meshing arcuate rack 61 on the transverse slide member 2 31, projecting upwardly into a co~respondingly shaped 3 recess (not shown) in the tool mount carrier 43 and a 4 meshing toothed partial pinion 62 mounted on or integrally formed as part of the tool mount 46. With 6 such an arrangement rotation of the tool mount carrier 43 7 about the vertical axis defined by the stud 41 will ~ automatically result in rotation of the tool mount 46 g about the axis de~ined by the spigot 47 due to the meshing inter-engagement of the ar~uate rack 61 and the 11 toothed partial pinion 62. Suitable dimensions and 12 positioning of these two components 61, 62 will ensure 13 that the angular displacement of the tool mount 46 is 14 related in the correct proportion to the angular displacement of the tool mount carrier 43. The degree of 16 inclination required will depend on ths length of the 17 edge 59 of tha tool to be sharpened with the intention 18 that it should contact the whole of the axial width of 19 the cylindrical ~urface of the.stone 54 a~ the tool edge is traversed past the stone. A relatively narrow chisel, 21 ~or~examp,le,,- wi,ll require a significant inclination i.n 22 order.,.to,achieve,this effect whereas a wider plane,iron 23 would requirs,.on~ly,a small incl.ination. By incli~i.ng,.the 24 edge 59 in this,way it i5 ensured~that even we~r,on.the stone 54 takeS place thereby minimising the localisation 26 of wear points and extending the life of the ~tone ~ .
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1310~97 1 between successive dressings. Dressing of the stone can 2 be achieved, of course, by placing an appropriate 3 dressing stone against one edge of the shroud 56 which, 4 being parallel to the axis of rotation of the stone 54, acts as a suitable restraint and guide for such dressing.
7 Turning now to Figure 5, an alternative tool mount 63 is 8 illustrated, which is adapted to be fitted onto the stud 9 41 projecting up from the transverse slide member 31.
The tool mount 63 is adapted for sharpening gouges, and 11 for this purpose is provided with two part cylindrical 12 parallel surfaces 64, 65 spaced by a rectilinear groove 13 66 parallel to the inclined front face 45 of the 14 corresponding tool mount carrier 43. An appropriate socket i5 formed in the lower face of the gouge tool 16 mount 63 to snable it to be fitted to the llppsr face of 17 the transverse slide member 31 onto the stud 41, although 18 in this casa rotation of the tool mount 63 about,the axis 19 defined by the stud 41 is not required and a suitable shoulder or lip for engaging over one edge of the 21 transverse slide 31 may be provided. In usg of this 22 embodiment a gouge 67 is positioned with its convexly 23 curved surface in contact with the two convex part 24 cylindrical surfaces 64, 65 and lying parallel to the groove 66. In this position the mount supports the tool ~6 in such a way that the reaction lines of orce between ,: ....
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1310~97 1 the mount 63 and the tool itself meet at the centre of 2 curvature of the tool so that laterally applied forces, 3 providing they maintain the tool in contact with the 4 bicuspid suraces 64, 65, cause the tool to perform a rotatio~ about its centre of curvature. This ensures ~ that the edge of a gouge i~ cAu~d to follow a curva 7 pa;rallel to that of the intersection b~tween its bevel 8 edge and its convex cylindrical surf~ce th~reby causing g it` to be sharp~ned against the grindstane 54 providing this latter has a smaller radius of curvature than that 11 of the tool. If the stone 54 has too greater a radius of 12 curvature it can be replaced with a small diameter stone 13 69 having a threaded shank 70 as shcwn in Figure 7, which 14 can be screwed into the upper end of the spindle on which the stone 54 is mounted (aEter having removed the stone 16 54 itself).
18 In order to sharpen a gouge having an external bevel the 19 mollnt 63 is removed from the cross slide 31 and ~rèpositioned in the orientation illustrated in Figure 8.
21 The inclined biscuspid faces 64, 65 now lie at a much 22 shallower angle to the horizontal and a gouge positioned 23 thereon can be brought into contact with the upper 24 circular face of the grindstone 54 instead of the cylindrically curved surface which is used for grinding 26 an inside bevel edge. The tool operates in the same way ' ~31~97 1 with the bicuspid surfaces 64, 65 causing the tool to be 2 turned about its centre of curvature when displaced 3 laterally whilst remaining in contact with the two curves 4 of the bicuspid surfaces 64, 65.
6 The approach of the tool to be sharpened to the stone 54 7 or the ston~ 69 can be controlled by turning the 8 butterfly knob 34 to cause relative approach or 9 withdraw~l of the tran~v~r~e ~lid~ 31. When sharpening a gouge 67, o course, it is not intended that the tool 11 mount c~rria~e 26 shall be displaced along the guide 12 rails 23, 24.
14 In Figure 6, an alternative tool mount assembly is shown in which, in place of the permanent magnets 50, 51 for 16 retaining a metal tool, there is provided a clamp 17 comprising two parallel jaws 74, 75 the first of which is 18 fixed to~an inclined support plate 76 carried fixedly on 19 the front face of a tool mount body in all respects similar to the tool mount 43. Two parallel guides 77, 21 78, the~latter of which is threaded, traverse the jaws 22 74, 75 and the threaded guide 78 carries a butterfly knob 23 79 ~or making adjustments to the separation of the jaws 24 74, 75. The threaded guide 78 is retained against displacement with respect to the fixed jaw 74 by a lock 26 nut arrangement 80 housed in a groove 81 of the fixed jaw . .
~310~97 1 74. A tool mount such as this may be considered more 2 suitable for a wide tool such as a plane iron which can 3 thereby be secured with a greater degree of security onto 4 the tool mount than would be the case relying solely on the magnets 50, 51.
. 7 The stone 54 may be driven to rotate about its axis by an `: 8 electric motor housed within the stone support part 13 of g the casing 11, or may alternatively be provided with bevel gears (not shown) linking it to a drive spindle 82 11 which can be gripped by, for example, the chuck of a 12 pistol drill. Instead of bevel gears a belt drive may be 13 ~mployed.
The inclination o~ the b~vel edge ground at the end of 16 the tool 53 can b~ determined by appropriately setting 17 the guide rail ~upport base 15 after having slackened the 18 clamp wheel 20, and the angle of the bevel can be read by 19 reference to the scale of graduations 25 against the top edge of the lateral support 16. As illustratad the edge 21 may be ground at anything between 15 and 3Q. Although 22 conventional chisels are ground only at 25 and/or 30 it 23 is envisaged that the sharpening machine of the present 24 invention will be capable of sharpening any edge tool, in particular turning and carving chisels which ar3 of 26 various shapes and hav~ edges inclined to ths length of 1 the tool at an angle other than 90. Appropriate 2 adjustment of the tool mount and the guide rail support 3 base will present the edge of the tool to b0 sharpened at 4 an appropriate angle so that, upon traversing the carriage 26 along the guide rails 23, 24 an appropriate 6 sdgs will be formed at the end of the tool.
8 Fine finishing of the edge by hand may be achieved, if 9 desired, by stroking the sharpened tool on the stationary slip stone 58 carried on the cover 57 over the shroud 56.
11 By appropriately choosing the material for the stone 54, 12 however, it is envisaged that such finishing operations 13 will rarely be required.
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~3~97 1 tool guide formed as a c~lindrical bar, but this tool too 2 provides a bevel facet which is hollow ground and, 3 furthermore, involves considerably complexity in the tool 4 mount.
9 A previous object of the present invention is to provide a fast, efficient, accurate and simple apparatus for 11 sharpening an edge tool which is easy to use and which 12 has a wide range of.application.
13 : , 14 Another object of the present invention is to provide apparatus for sharpeni.ng an edge tool which is suitable 16 for both professional and ama-teur alike whilst being of 17 reasonable cost.
19 A further object of the present invention i~ to provide apparatus.for sharpening edge tools having both straight 2.1 and.curved cutting edges.
23 ..^ . . ..SUMMARY OF THE INVENTION
26 According to the present invention, there is provided 131 ~9P~
1 apparatus for sharpening an edge tool having a llnear 2 cutting edge, such as a chisel, a plane iron or a gouge, 3 com~rising a rotary grinding stone having a cylindrically 4 curved surface mounted for rotation about an axis coincident with the axis of the cylinder and tool 6 mounting means on which an edge tool to be sharpened can 7 be located, the tool mounting means including guide means 8 oriented such that relative movement between the tool and 9 the rotary grinding stor,e can take place substantially perpendicular to the plane including the point of contact 11 between the edge tool and the stone and the axis of the 12 grindstone.
13 .i~ ' 14 By providing this arrangement, in which the relative movement of the stone and the tool being sharpened is 16 orthogonally located with respect to that employed in 17 known tool sharpening machines it is possible to make use 18 of a relative.ly small stone whilst nevertheless.being 1~ able to sharpen edge tools such as chisels and plane irons the length of the cutting edges o~ which are very 21 substantially different from one another.
23 Preferably the tool mounting means of the present 24 apparatùs includes means for retaining an edge tool in a selectable de,termined orientation with respect to,the 26 axis of roTtation of the rotary grinding stone. This . . ~ , ~310~97 1 enables not only the honed edye, but also a relief angle 2 to be ground on a tool. It is known, for example, that 3 chisels are usually ground to an angle of 25 to the 4 plane of the flat face of the tool, with a narrow strip along the cutting edge being honed to an angle in the 6 region of 30. The apparatus of the present invention 7 makes it possible for both ground faces to be formed 8 easily and quickly.
Preferably the tool mounting means is adjustable such 11 that the inclination oE the edge of an edge tool to be 12 sharpened with respect to the line of relative,movement 13 between the tool mounting means and the rotary grindstone 14 is adjustable over a range of inclination with ,the~said edge lying in a plane parallel to both the axis of 16 rotation of the grindstone and the line of relative 17 movement between the tool mounting means and the 18 grindstone.
The tool mounting means pre~erably include a tool mount 21 which can be ,fit~ted to an underlying support in one of 22 two pre-determined.orientations whereby to select one of 23 two angles at,wh,ich the edge of the tool is to be ground.
24 Thi3 adjustment can also be used, as will be explained in more detail ,be.low, to select when an internal,or external 26 edge is formed on a curved tool such as a gouge. It will lC~04s7 1 be appreciated tha-t gouges are formed in two types, bo~h 2 having basically a cylindrically curved steel body, but 3 one type having a bevel edge cut on the convex or outer 4 face at the end of the body whilst the other type has a bevel edge Eormed on th0 concave or inner face thereof.
6 Such gouges are used for cutting internal and external 7 curves respectively, for example when producing parallel 8 flutes or other decorative work.
The path of relative movemellt between the edge tool to be 11 sharpened and the rotary grinding stone may be 12 substantially~rectilinea~, as in the case of chisels and 13 plane irons, but may be made curvilinear by adaptation 14 using an adapter to allow sharpening of curved-edge tools, such as gouges.
17 Different embodiments of the invention may be provided 18 with different arrangements for driving the rotary 19 movement of the stone. For example, the rotary grindstone may be mounted on bearings fixedly located 21 within a casing of the apparatus and the relative 22 movement between the tool to be sharpened and the rotary 23 grindstone effected by displacement of the tool alon~ a 24 determined path with respec-t to the casing and thus with respect to the;rotary grindstone. Alternatively, 26 however, the tool could be held stationary on the casing ,.
,' ' ~10~97 1 and the stone arranged to be movable with respect 2 thereto, such movement being effected by lateral 3 translation o~ the stone spindle p~rpendicular -to its 4 length. Such movemen-t would necessarily need to be linear or curved in a plane including the line of the 6 cutting edge (in the case of a rectilinear cutting edge) 7 or curved to match the curve of the cutting edge (in the 8 case of a curvilinear cutting edge).
The rotary grindstone is conveniently mounted on a 11 spindle of a spindle assembly driven by a motor carried 12 within the casing of the apparatus, and the motor may be 13 fixedly located or mounted so as to be movable with the 14 stone. Alternatively, the rotary grindstone may be mounted on a freely rotatable spindle assembly having an 16 input end ~hich projects from the casing of the apparatus 17 for atta~hment to a removably attachable drive motor such 18 as a hand held pistol drill.
To achieve this end the spindle assembly preferably 21 incudes a grindstone spindle on which the r~tary 22 grindstone is mounted, a drive input spindle lying at an 23 angle to the grindstone spindle, and a bevel gear 24 transmission linking the two for transmission of rotary motion from the drive input spindle to the grindstone 26 spindle. To simplify manufacturing processes this . / , . , - .
~310497 , g 1 arrangement can also be used in embodiments having an 2 integral ~otor, with the bevel gear being turned through 3 90 such that the input shaft lies parallel to the casing 4 wall rather than perpendicular thereto as in the case of ; 5 the embodiment intended for connection to an external ;~` 6 motor.
8 The tool mounting means of the apparatus of the present 9 lnvention may comprise a tool mount turnable about an axis perpendicular to the plane of a tool mount face 11 thereof and a tool mount carrier turnable about an axis 12 parallel,.~to the axis of the grindstone. In suchjan 13 arrangement it is.possible that the tool mount and tool 14 mount carrier are interconnected so that ar.gular displacement of~the tool mount carrier about its axis is 16 associated with related angular displacement of:the~tool 17 mount about its axis with respect to the tool mount 18 carrier in such a way that one edge of the t~ol mount 19 always lies in a plane parallel to both the axis of rotation of the grindstone and the line of displacement 21 of the tool mount assembly along the rectilinear guide 22 meaps.. .. ..
23 ,i.~.:.~. ,~ ,.. :. - ..~
24 The tool mountin.g means may include a support b,ody ~, displaceable parallel to the said guide and a tool 26 carrier which,is displaceable with respect to the.support .
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' 1 body in a direction perpendicular to the rectilinear 2 guide. The tool carrier may itself likewise be formed in 3 two parts, a first part permanently fitted to the support 4 body and displaceable with respect thereto as a carriage in the said perpendicular direction, and a second part or 6 tool mount removably attachable to the carriage and 7 interchangeable with similar such -tool mounts adapted for 8 receiving different tools to be sharpened.
In a preferred embodiment of the present invention the 11 said rectilinear guide means is formed as a pair of 12 parallel rods mounted fixedly on -the casing with a 13 pre-determined spacing therebetween, and the support body 14 is slidable therealong. Such sliding contact may be provided by means of plain bearings, or by rolling 16 element bearings in a backlash-free configuration, such 17 as a recirculating ball bearing. Alternatively, the 18 rectilinear guide may be in the form of a V-block 19 receiving contact members of an appropriate carriage.
21 The~rectilinear guide means may include means for varying 22 the inc~lination of a tool mount about an axis parallel to 23 the length of the recti]inear guide means whereby to 24 adjust the angle at which a bevel facet at the edge of the tool is ground.
`` 1310497 1 Preferably the said support body is formed with or 2 carries rectilinear yuide means for the tool carrier to 3 guide the said tool carrier in the said perpendicular 4 direction to advance a tool carried thereby towards a line of intersection with the grindstone whereby to 6 determine the amount of material removed in a pass of the 7 tool and grindstone upon relative movement therebetween.
8 The said support body and the tool carrier are 9 conveniently interlinked by screw threaded motion control means operable to cause such relative movement between 11 them with a controllable fine adjustment of the relative 12 positions thereof whereby to set the amount of material 13 removed from the tool in such a pass between the tool 14 mounting means and the ~rindstone upon relative movement between them.
18 The interconnection between the tool mount and the 19 carriage of the tool carrier may be iormed, as in the preferred embodiment, by means of a projection on the or 21 each tool mount, which projection has a dovetail 22 cross-section~which can be introduced into a groove of 23 complementary.,dovetail cross-section in the said !
24 carriage. One of these two preferably has clamping means for securing them toge-ther when the dovetail proj,ection 26 has been fitted into the dovetail groove.
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310~97 2 Different tool mounts may be shaped specifically to 3 receive different kinds of tools. For example, the tool ~ mount may have at least one substantially flat face for locating ~ corresponding:ly flat face of a tool to be 6 sharpened. This flat face may be inclined with respect 7 to the dovetail projection and there may be provided a 8 second dovetail projection at a different angle from that 9 of the first so that the inclined face can be presented in one of two inclinations whereby to offer the edge tool 11 at one or the other of two different inclinations to the 12 grindstone. For a different tool, such as gouge, the 13 tool mount may have a convexly curved bicuspid curvature 14 to receive a cylindrically curved surface of a tool to be sharpened, allowing relative movement thereof with 16 respect to the said tool carrier about an axis coincident 17 with.that of the said cylindrically curved surface..of the 18 tool to be sharpened.
19 ~ . : . ;.
Whatever the form of the tool mount there are preferably 21 provided retainer means for retaining a tool to be 22 sharpened with a face thereof in contact with a face of 23 the tool mount. Such re~ainer means may comprise an arm 24 projecting from the tool moun-t with a lateral finger pro~ecting therefrom whereby partly to encircle the tool 26 to be sharpened and draw it into contact with the said ; . -. 1. . ' -.. ..
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- 1310~97 .
1 one face of the tool mount. Other forms of retainer may, 2 alternatively, be employed.
4 As an addition, the casing may further include a housing for a substantially flat stationary grindstone against 6 which a tool can be worked for cleaning of any burrs 7 producsd by the rotary grindstone in use of the 8 apparatus. The rotary grindstone is preferably made of 9 an abrasive laminate, and it has been found that a cloth/abrasive laminate is of particular utility.
11 Alternatively, however, often abrasive materials may be 12 employed, such~ as a plasma sprayed ceramic on a metal 13 base having a grit-blasted surface.
Other features and advantages of the present invention 16 will become appararent from a study of the following 17 detailed description in which reference is made to the 18 accompanying drawings, provided purely by way of 19 non-limitative example only.
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21 ~ i BR I EF DESCR I PT I ON OF THE DRAW I N~S , 23 ~ i 24 Figure 1 is a perspective view of the first embodiment of the invention seen from the front;
26 Figure 2 is a perspective view of the embodiment of 1~10~97 1 Figure 1 ~een from the rear;
2 Figurs 3 is an enlarged perspective view of the 3 tool mount of the embodiment of Figure 1;
4 Figur~ 4 is a cross-section through the tool mount taken on the line IV-IV of Figure 1;
' 6 Figure 5 is a perspective view o~ an alternative 7 tool mount different from that illustrated in Figures 3 8 and 4;
: 9 Figure 6 is a perspective view of a further alternative tool mount;
11 Figure 7 is a side view illustrating one way in `: 12 which.the toQl mount~of Figure 5 can be set up for 13 grinding an internal ly bevelled gouge; and 14 Figure 8 is a side view illustrating a second configuration,i~,which the tool mount of Figure.,5 c,an.be set for grinding an e~ternally bevelled gouge.
19 DESCRIPTION,OF THE PREFERRED EMBQDIMENTS
2~
22 The appar,at,us shown in Figure 1 of the drawings comp,rises 23 a,casing..ge,~!era;lly.,indicated 11 having a slide body part 24 12 and a ~.tone support part 13. The slide body part 12 has an inclined;upper,face 14 over which is positioned a 26 guide rail,,s,upport base 15 which i~ aarried at, each end :`
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~10497 1 by upwardly projecting lateral supports 16, 17 secured at 2 each end of the slide body part 12 of the casing. The 3 guide rail support base 15 is pivoted to turn about a 4 horizontal axis X-X which coincides with the pivotal attachment of the guide rail support base 15 to the 6 lateral supports 16 and 17, which is evidenced in Figures 7 1 and 2 by the attachment nut 18 which sacures a plVOt 8 19.
The lateral supports 16, 17 each have an arcuate slot 11 (not shown) through which passes a threaded pin attached 12 to the guidq rail support base 15 and on to which is 13 screwed a clamp wheel 20. A similar clamp wheel is~
14 positioned in~r.elation to the lateral support 1~, but is not visible in the drawings. -,.
17 At each end.of~the guide rail support.base 15 are two 18 guide rail support blocks 21, 22 in which are secured two 19 parallel guide rails 23, 24. On one of the guide rail support blocks, namely the block 21, there is marked a 21 scale of graduations generally indicated with the 22 reference numeral 25, which can be referenced against the 23 upper odge of the lateral support 16 to determine the 24 angul~r posi.ti~on of the plane defined by the t.wo guide rail~.~23, 24 in relation to the slide body part,12 o the 26 casing or reasons which will bq described in more detail .
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1310~1~7 belowO
' ~ 2 ` ~ 3 Slidably carried on the parallel rails 23, 24 is a tool 4 mount carriage generally indicated 26, which comprises a main carriage body 27 beneath which is secured a reaction 6 plate 28. The main c.arriage body 27 and the reaction ; 7 plate 28 have respective parallel part cylindrical 8 grooves in which the guide rails 23, 24 are received and 9 the reaction plate 28 is biased, with respect to the main carriage body 27 by means of a biasing spring 29 which 11 can be seen in Figure 4. Adjustment screws (not shown) : 12 determlne tho force applied between the reaction plate 28 1~ and the main carriage ~ody 27 so that the frictional 14 resistance ex~erienced by the tool mount carriage,26 as it is displaced along the guide rails 23, 24 can be 16 adju ted. Conveniently the main carriage body 27 and 17 reaction plate 28 are made from a plastics material 18 having a relatively low coefficient o friction,, whilst 19 the ~uide r,a,ils.23, 24 may be made from a metal or,other m:aterial-wh~ichlcan be highly polished so tha~;again~
21 there~is a,lowi,~rictional re~istance-between the rai.ls 22 and the tool.mount carriage as this is displaced to~and 23 fro.along th,s guide rails.
: 25 The main carriage body 27 has a recess 30 in its upper 26 face to form a guide for a transverse slide member 31 .
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13~0~97 : 1 which,~as can be seen in Figure 4, has a downwardly 2 pro~ecting threaded boss 32 engaged by a threaded shaft 3 33 on one end of which is a butterfly knob 34. The shaft 4 33 is threaded only along its intermediate section and has plain bearings 35, 36 at each end and is restrained 6 from axial movement by a washer 37 and lock pin 38 at one ~ 7 end, and by a pair o~ lock nuts 39, 40 at the other. By ; 8 turning the butterfly knob 34, therefore, linear 9 displacement of the transverse slide member 31 can be achieved in a direction transverse the length o the 11 guide rails 23, 24.
~ 12 ~ , : 13 In the upper::face.of the transverse slide member 31 is a 14 socket receivin~ a,stud 41 which is a tight fit therein and which may.be-secured in position,.for example by 16 : adhesives. The stud 41 serves as a locating peg and 17 pivot for a tool mount assembly generally indicated 42 ~ 18 and comprising a tool mount carrier 43 which has a 19 vertical rear face 44 and an inclined front face 45.
Piqotally mounted to the front face 45 of the tool mount 21 ca~rier 43 is the,tool mount itself, indicated with the : . .
22 ~qference numaral 46, which has a generally planar .
23 configuration and a central rearwardly projecting;spigot 24 47 received,i,n.,a,correspondingly shaped socket,48 in the inclined face,4.5 of the tool mount.c~rrier 43. Th,e tool 26 mount 46 has a ~lat front face 49 in which are housed two ..
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i310~97 1 permanent magnets 50, 51 for retaining a metal tool such 2 as a chi~el or plane iron in position when engagad 3 thereon. At one side of the tool mount 46 is an 4 upstanding shoulder 52 which serves as a locating abutment for one side of a tool 53 when positioned with 6 its major face flat against the flat front face 49 of the 7 tool mount 46, in which position it will be retained by 8 the permanent magnets 50 and 51.
The stone support part 13 of the casing carries a 11 vertical spindle (not shown) on the upper end of which is 12 secured a rotary grindstone 54 of the so-called "cup"
13 type having a central recess 55 in its upper circular 14 flat face through-which access can be gained to,a nut securing the.s.tone 54 on the upper end of the spindle.
16 For reasons which.will be explained in.more deta.il below 17 the æpind-le.itself may have an axial threaded hole,at one 18 end as well as an.externally threaded portion for 19 receiving the securing nut which retains the stone 54 in position. The stone support part 13 of the casing 11 21 includes a semi-cyllndrical shroud 56 which~encloses the 22 stone 54 over approximately one half o~ its circumference 23 and the shroud 56 is provided with a removable cover 57 24 carrying a stationary ~ine slip stone 58.
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26 In use,~f ~the embodiment desaribed above a tool s,uch as -- ; ; , . .
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1 the chisel 53 illustrated in broken outline in Figure 3, 2 is positioned on the flat front face 49 of the tool mount 3 46 so that its edge 59 is closely adjacent the ~ 4 cylindrical surface of the rotary grindstone 54. By : 5 turnin~ the tool mount 46 about the axis defined by the 6 s~igot 4? the ed~e 59 of the tool 53 can be incl ined so 7 that it occupies a vertical distance corresponding to the 8 axial dimenslon of the stone 54. However, since the axis 9 defined by the spigot 47 is inclined to the axis of rotation of the stone 54 this movement will, when viewed 11 in plan, leave the edge 59 of the tool at an inclination 12 to the line of travel of the tool mount carriage 26 on 13 the guide rails 23, 24 so that as the carriage 26 is 14 displaced to and fro along the guide rails 23, 24 only , ~` ~ 15 the proximal corner 60 of the edge 59 of the tool 53 will ` 1 b come inta contact with the grindstone 54. To compensate . ~
17. ~or this, there~orei the tool mount body is tur~ed,~about 18 tha ve~tical ~xi~ defined by the stud 41 until:the edge 19 59 is again parallel to the line defined by the guide rails 23" 24. The~e two movements may be made entirely 21 independently,~as in the embodiment illustr~ted, leaying ~2 the operator -to:~udge the precise position of the tool 23 mount carrier 43 and the tool mount 46 to establish the 24 correct alignmant of the edge 59 of the tool or, as illustrated in broken outline in Figure 4, a m~chanical 26 interlink may be provided, for example in the form of a :
~, ~
~310~7 : 1 meshing arcuate rack 61 on the transverse slide member 2 31, projecting upwardly into a co~respondingly shaped 3 recess (not shown) in the tool mount carrier 43 and a 4 meshing toothed partial pinion 62 mounted on or integrally formed as part of the tool mount 46. With 6 such an arrangement rotation of the tool mount carrier 43 7 about the vertical axis defined by the stud 41 will ~ automatically result in rotation of the tool mount 46 g about the axis de~ined by the spigot 47 due to the meshing inter-engagement of the ar~uate rack 61 and the 11 toothed partial pinion 62. Suitable dimensions and 12 positioning of these two components 61, 62 will ensure 13 that the angular displacement of the tool mount 46 is 14 related in the correct proportion to the angular displacement of the tool mount carrier 43. The degree of 16 inclination required will depend on ths length of the 17 edge 59 of tha tool to be sharpened with the intention 18 that it should contact the whole of the axial width of 19 the cylindrical ~urface of the.stone 54 a~ the tool edge is traversed past the stone. A relatively narrow chisel, 21 ~or~examp,le,,- wi,ll require a significant inclination i.n 22 order.,.to,achieve,this effect whereas a wider plane,iron 23 would requirs,.on~ly,a small incl.ination. By incli~i.ng,.the 24 edge 59 in this,way it i5 ensured~that even we~r,on.the stone 54 takeS place thereby minimising the localisation 26 of wear points and extending the life of the ~tone ~ .
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1310~97 1 between successive dressings. Dressing of the stone can 2 be achieved, of course, by placing an appropriate 3 dressing stone against one edge of the shroud 56 which, 4 being parallel to the axis of rotation of the stone 54, acts as a suitable restraint and guide for such dressing.
7 Turning now to Figure 5, an alternative tool mount 63 is 8 illustrated, which is adapted to be fitted onto the stud 9 41 projecting up from the transverse slide member 31.
The tool mount 63 is adapted for sharpening gouges, and 11 for this purpose is provided with two part cylindrical 12 parallel surfaces 64, 65 spaced by a rectilinear groove 13 66 parallel to the inclined front face 45 of the 14 corresponding tool mount carrier 43. An appropriate socket i5 formed in the lower face of the gouge tool 16 mount 63 to snable it to be fitted to the llppsr face of 17 the transverse slide member 31 onto the stud 41, although 18 in this casa rotation of the tool mount 63 about,the axis 19 defined by the stud 41 is not required and a suitable shoulder or lip for engaging over one edge of the 21 transverse slide 31 may be provided. In usg of this 22 embodiment a gouge 67 is positioned with its convexly 23 curved surface in contact with the two convex part 24 cylindrical surfaces 64, 65 and lying parallel to the groove 66. In this position the mount supports the tool ~6 in such a way that the reaction lines of orce between ,: ....
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1310~97 1 the mount 63 and the tool itself meet at the centre of 2 curvature of the tool so that laterally applied forces, 3 providing they maintain the tool in contact with the 4 bicuspid suraces 64, 65, cause the tool to perform a rotatio~ about its centre of curvature. This ensures ~ that the edge of a gouge i~ cAu~d to follow a curva 7 pa;rallel to that of the intersection b~tween its bevel 8 edge and its convex cylindrical surf~ce th~reby causing g it` to be sharp~ned against the grindstane 54 providing this latter has a smaller radius of curvature than that 11 of the tool. If the stone 54 has too greater a radius of 12 curvature it can be replaced with a small diameter stone 13 69 having a threaded shank 70 as shcwn in Figure 7, which 14 can be screwed into the upper end of the spindle on which the stone 54 is mounted (aEter having removed the stone 16 54 itself).
18 In order to sharpen a gouge having an external bevel the 19 mollnt 63 is removed from the cross slide 31 and ~rèpositioned in the orientation illustrated in Figure 8.
21 The inclined biscuspid faces 64, 65 now lie at a much 22 shallower angle to the horizontal and a gouge positioned 23 thereon can be brought into contact with the upper 24 circular face of the grindstone 54 instead of the cylindrically curved surface which is used for grinding 26 an inside bevel edge. The tool operates in the same way ' ~31~97 1 with the bicuspid surfaces 64, 65 causing the tool to be 2 turned about its centre of curvature when displaced 3 laterally whilst remaining in contact with the two curves 4 of the bicuspid surfaces 64, 65.
6 The approach of the tool to be sharpened to the stone 54 7 or the ston~ 69 can be controlled by turning the 8 butterfly knob 34 to cause relative approach or 9 withdraw~l of the tran~v~r~e ~lid~ 31. When sharpening a gouge 67, o course, it is not intended that the tool 11 mount c~rria~e 26 shall be displaced along the guide 12 rails 23, 24.
14 In Figure 6, an alternative tool mount assembly is shown in which, in place of the permanent magnets 50, 51 for 16 retaining a metal tool, there is provided a clamp 17 comprising two parallel jaws 74, 75 the first of which is 18 fixed to~an inclined support plate 76 carried fixedly on 19 the front face of a tool mount body in all respects similar to the tool mount 43. Two parallel guides 77, 21 78, the~latter of which is threaded, traverse the jaws 22 74, 75 and the threaded guide 78 carries a butterfly knob 23 79 ~or making adjustments to the separation of the jaws 24 74, 75. The threaded guide 78 is retained against displacement with respect to the fixed jaw 74 by a lock 26 nut arrangement 80 housed in a groove 81 of the fixed jaw . .
~310~97 1 74. A tool mount such as this may be considered more 2 suitable for a wide tool such as a plane iron which can 3 thereby be secured with a greater degree of security onto 4 the tool mount than would be the case relying solely on the magnets 50, 51.
. 7 The stone 54 may be driven to rotate about its axis by an `: 8 electric motor housed within the stone support part 13 of g the casing 11, or may alternatively be provided with bevel gears (not shown) linking it to a drive spindle 82 11 which can be gripped by, for example, the chuck of a 12 pistol drill. Instead of bevel gears a belt drive may be 13 ~mployed.
The inclination o~ the b~vel edge ground at the end of 16 the tool 53 can b~ determined by appropriately setting 17 the guide rail ~upport base 15 after having slackened the 18 clamp wheel 20, and the angle of the bevel can be read by 19 reference to the scale of graduations 25 against the top edge of the lateral support 16. As illustratad the edge 21 may be ground at anything between 15 and 3Q. Although 22 conventional chisels are ground only at 25 and/or 30 it 23 is envisaged that the sharpening machine of the present 24 invention will be capable of sharpening any edge tool, in particular turning and carving chisels which ar3 of 26 various shapes and hav~ edges inclined to ths length of 1 the tool at an angle other than 90. Appropriate 2 adjustment of the tool mount and the guide rail support 3 base will present the edge of the tool to b0 sharpened at 4 an appropriate angle so that, upon traversing the carriage 26 along the guide rails 23, 24 an appropriate 6 sdgs will be formed at the end of the tool.
8 Fine finishing of the edge by hand may be achieved, if 9 desired, by stroking the sharpened tool on the stationary slip stone 58 carried on the cover 57 over the shroud 56.
11 By appropriately choosing the material for the stone 54, 12 however, it is envisaged that such finishing operations 13 will rarely be required.
19 ~ :
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Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for sharpening an edge tool having a linear cutting edge, comprising:
- a rotary grinding stone having a cylindrical curved surface, - means mounting said rotary grinding stone for rotation about an axis coincident with the axis of said cylindrically curved surface, and - tool mounting means including:
- guide means for guiding relative movement between said edge tool to be sharpened and said rotary grinding stone, said guide means guiding said relative movement between said edge tool and said rotary grinding stone to lie in a displacement plane which is substantially perpendicular to the plane including the point of contact between said edge tool and said rotary grinding stone and the axis of rotation of said rotary grinding stone, a tool mount having a tool mount face and being turnable about an axis perpendicular to the plane of said tool mount face, and - a tool mount carrier turnable about an axis parallel to said axis of rotation of said rotary grindstone, said tool mount and said tool mount carrier being connected together so that angular displacement of said tool mount carrier about its axis is associated with related angular displacement of said tool mount about its axis with respect to said tool mount carrier in such a way that one edge of said tool mount always lies in a plane parallel to said displacement plane.
- a rotary grinding stone having a cylindrical curved surface, - means mounting said rotary grinding stone for rotation about an axis coincident with the axis of said cylindrically curved surface, and - tool mounting means including:
- guide means for guiding relative movement between said edge tool to be sharpened and said rotary grinding stone, said guide means guiding said relative movement between said edge tool and said rotary grinding stone to lie in a displacement plane which is substantially perpendicular to the plane including the point of contact between said edge tool and said rotary grinding stone and the axis of rotation of said rotary grinding stone, a tool mount having a tool mount face and being turnable about an axis perpendicular to the plane of said tool mount face, and - a tool mount carrier turnable about an axis parallel to said axis of rotation of said rotary grindstone, said tool mount and said tool mount carrier being connected together so that angular displacement of said tool mount carrier about its axis is associated with related angular displacement of said tool mount about its axis with respect to said tool mount carrier in such a way that one edge of said tool mount always lies in a plane parallel to said displacement plane.
2. The apparatus of claim 1, wherein said tool mounting means includes means for retaining an edge tool in a selectable determined orientation with respect to said axis of rotation of said rotary grinding stone.
3. The apparatus of claim 2, wherein said tool mounting means is adjustable such that the inclination of the edge of an edge tool to be sharpened is adjustable with respect to said displacement plane whereby to adjust the angle of the edge ground on the said edge tool by the said apparatus.
4. The apparatus of claim 1, wherein said guide means define a rectilinear path of relative movement between said tool mounting means for said edge tool to be sharpened and said rotary grindstone.
5. The apparatus of claim 1, wherein said apparatus is encased in a casing and said rotary grindstone is mounted on a freely rotatable spindle assembly having an input end which projects from said casing of said apparatus for attachment to a removably attachable drive motor of a pistol drill.
6. The apparatus of claim 5, wherein said spindle assembly includes a grindstone spindle on which said rotary grindstone is mounted.
- a drive input spindle lying at an angle to said grindstone spindle, and - a bevel gear transmission linking said two spindles for transmission of rotary motion from said drive input spindle to said grindstone spindle.
- a drive input spindle lying at an angle to said grindstone spindle, and - a bevel gear transmission linking said two spindles for transmission of rotary motion from said drive input spindle to said grindstone spindle.
7. The apparatus of claim 1, wherein said tool mounting means include:
- a slide member displaceable in a direction perpendicular to said rectilinear guides.
- a slide member displaceable in a direction perpendicular to said rectilinear guides.
8. The apparatus of claim 7, wherein said slide member is provided with engagement means operating to retain said tool mount carrier whilst permitting angular displacement thereof about an axis parallel to said axis of rotation of said rotary grindstone.
9. The apparatus of claim 1, wherein said guide means is formed as a pair of parallel rods mounted fixedly on a casing of said apparatus with a predetermined spacing therebetween, and said tool mount is slidable therealong.
Apparatus for sharpening an edge tool having a linear cutting edge, comprising:
- a rotary grinding stone having a cylindrically curved surface, - means mounting said rotary grinding stone for rotation about an axis coincident with the axis of said cylindrically curved surface, and - tool mounting means including a tool mount for locating a tool to be sharpened, and guide means for guiding relative movement between said edge tool to be sharpened and said rotary grinding stone, said guide means guiding said relative movement between said edge tool and said rotary grinding stone to lie in a displacement plane which is substantially perpendicular to the plane including the point of contact between said edge tool and said rotary grinding stone and the axis of rotation of said rotary grinding stone, and said tool mount being adjustable about two inclined axes less than 90° to one another, one of which is parallel to the axis of said rotary grinding stone, whereby adjustments to the position of the edge tool carried thereby can be made to locate the edge of the tool in a plane parallel to the said displacement plane and at an inclination such that the projection of the edge parallel to the axis of rotation of the grinding stone is shorter in length than the axial length of the grinding stone itself.
- a rotary grinding stone having a cylindrically curved surface, - means mounting said rotary grinding stone for rotation about an axis coincident with the axis of said cylindrically curved surface, and - tool mounting means including a tool mount for locating a tool to be sharpened, and guide means for guiding relative movement between said edge tool to be sharpened and said rotary grinding stone, said guide means guiding said relative movement between said edge tool and said rotary grinding stone to lie in a displacement plane which is substantially perpendicular to the plane including the point of contact between said edge tool and said rotary grinding stone and the axis of rotation of said rotary grinding stone, and said tool mount being adjustable about two inclined axes less than 90° to one another, one of which is parallel to the axis of said rotary grinding stone, whereby adjustments to the position of the edge tool carried thereby can be made to locate the edge of the tool in a plane parallel to the said displacement plane and at an inclination such that the projection of the edge parallel to the axis of rotation of the grinding stone is shorter in length than the axial length of the grinding stone itself.
11. The apparatus of claim 10, wherein said guide means include means for varying the inclination of said tool mount about an axis parallel to the length of said guide means whereby to adjust the angle at which a bevel facet at the edge of a said tool to be sharpened is ground.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 577975 CA1310497C (en) | 1988-09-21 | 1988-09-21 | Apparatus for sharpening edge tools |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 577975 CA1310497C (en) | 1988-09-21 | 1988-09-21 | Apparatus for sharpening edge tools |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1310497C true CA1310497C (en) | 1992-11-24 |
Family
ID=4138759
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 577975 Expired - Lifetime CA1310497C (en) | 1988-09-21 | 1988-09-21 | Apparatus for sharpening edge tools |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1310497C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113798932A (en) * | 2021-10-25 | 2021-12-17 | 泰州市利优精密机械有限公司 | Numerical control blade grinding machine with automatic discharge function |
| CN117773693A (en) * | 2024-02-23 | 2024-03-29 | 山东弘方液压科技集团有限公司 | Grinding machine for processing breaking hammer |
-
1988
- 1988-09-21 CA CA 577975 patent/CA1310497C/en not_active Expired - Lifetime
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113798932A (en) * | 2021-10-25 | 2021-12-17 | 泰州市利优精密机械有限公司 | Numerical control blade grinding machine with automatic discharge function |
| CN113798932B (en) * | 2021-10-25 | 2024-04-02 | 泰州市利优精密机械有限公司 | Numerical control blade grinding machine with automatic discharging function |
| CN117773693A (en) * | 2024-02-23 | 2024-03-29 | 山东弘方液压科技集团有限公司 | Grinding machine for processing breaking hammer |
| CN117773693B (en) * | 2024-02-23 | 2024-04-30 | 山东弘方液压科技集团有限公司 | Grinding machine for processing breaking hammer |
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