CA1191428A - Cutting tool having means for heating a workpiece - Google Patents
Cutting tool having means for heating a workpieceInfo
- Publication number
- CA1191428A CA1191428A CA000402068A CA402068A CA1191428A CA 1191428 A CA1191428 A CA 1191428A CA 000402068 A CA000402068 A CA 000402068A CA 402068 A CA402068 A CA 402068A CA 1191428 A CA1191428 A CA 1191428A
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- cutting
- cutting tool
- tool according
- blades
- teeth
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Abstract
ABSTRACT OF THE DISCLOSURE
A cutting tool has a plurality of cutting teeth.
An electric voltage is applied between adjacent teeth so that a localized heating of the workpiece occurs at and around the cutting tips, in order to facilitate the cutting step. The volltage may be varied in such manner as to prevent or induce non linear cutting.
A cutting tool has a plurality of cutting teeth.
An electric voltage is applied between adjacent teeth so that a localized heating of the workpiece occurs at and around the cutting tips, in order to facilitate the cutting step. The volltage may be varied in such manner as to prevent or induce non linear cutting.
Description
BACKGROUND AND GBJECTS OF THE INVENTIOW
The present invention relates to the cutting of materials and, in particular, to cutting tools.
When cutting different materials, for example wood, by means of cutting tools capable of sawing, pla~ing, and milling, etc., it has been possible to facilitate the cuttiny work and increase production by heating the material.
The cost for heating will be dependent to some extent on the needed temperature increase and, as a rule, to even a greater extent on the size of the workpiece. Usually, the larger workpieces are to ~e heat~d to facilitate cutting of one single cut through the piece. Further, this heating is done by time-consuming convection and conduction. As a result, it is only for certain special purposes that the heating 15 technique has been suitable for applications such as veneer lathing, for example. Here, heating is necessary so that the wood can be cut and at the same time, the total heating will be well util.ized. The larger part of the whole-heated woodmass ; will then be cut. Another purpose for the heating technique is the sawing of frozen wood~
a~6 According to the invention, an effective heatiny o~
only the actual area beiny cut is achieved. The heating is carried out by electric means and is confined at -the cuttiny wedge tip and influences only the small part of -the material (wood) that will be cut. On other large parts of the material which shall not be worked on~ no energy is wasted.
The saw blade or the circular saw is preferably made of two parts with insulation therebetween. The saw blades are connected to an electrical voltaye so that between the wedyes, or between them and a third electrode, a heavy field strength is created, resulting in a strong local heating of the workpiece in the vicinity of the wedge-tips.
The saw can be of a conventional type with fixed teeth or ones which are mutually movable. The invention can also be applied to knives which are spread apart and in~
sulation is arranged between the parted units. In the case where there are two knife-blades as described in Swedish Patents 313S429 and 324,326, the insulation is applied between the knives. If the material in the work-piece has a high electrical conductivity, for example metal, the heating current is produced by ohmic resistance, from a suitable DC-source or AC-source with low frequency. When working on material with low conductivity, for example wood, plastics, etc., the ener~y isapplied dielectrical-ly with high frequency. The heat is concentrated in the ~?
The present invention relates to the cutting of materials and, in particular, to cutting tools.
When cutting different materials, for example wood, by means of cutting tools capable of sawing, pla~ing, and milling, etc., it has been possible to facilitate the cuttiny work and increase production by heating the material.
The cost for heating will be dependent to some extent on the needed temperature increase and, as a rule, to even a greater extent on the size of the workpiece. Usually, the larger workpieces are to ~e heat~d to facilitate cutting of one single cut through the piece. Further, this heating is done by time-consuming convection and conduction. As a result, it is only for certain special purposes that the heating 15 technique has been suitable for applications such as veneer lathing, for example. Here, heating is necessary so that the wood can be cut and at the same time, the total heating will be well util.ized. The larger part of the whole-heated woodmass ; will then be cut. Another purpose for the heating technique is the sawing of frozen wood~
a~6 According to the invention, an effective heatiny o~
only the actual area beiny cut is achieved. The heating is carried out by electric means and is confined at -the cuttiny wedge tip and influences only the small part of -the material (wood) that will be cut. On other large parts of the material which shall not be worked on~ no energy is wasted.
The saw blade or the circular saw is preferably made of two parts with insulation therebetween. The saw blades are connected to an electrical voltaye so that between the wedyes, or between them and a third electrode, a heavy field strength is created, resulting in a strong local heating of the workpiece in the vicinity of the wedge-tips.
The saw can be of a conventional type with fixed teeth or ones which are mutually movable. The invention can also be applied to knives which are spread apart and in~
sulation is arranged between the parted units. In the case where there are two knife-blades as described in Swedish Patents 313S429 and 324,326, the insulation is applied between the knives. If the material in the work-piece has a high electrical conductivity, for example metal, the heating current is produced by ohmic resistance, from a suitable DC-source or AC-source with low frequency. When working on material with low conductivity, for example wood, plastics, etc., the ener~y isapplied dielectrical-ly with high frequency. The heat is concentrated in the ~?
- 2 --cu-tting area of -the material paxtly due to -the sharp wedges and partly because the di.stance between electrically cooperating teeth is shor-t. Areas with a greater distance from the wedges thus will not be even slightly heated.
The saw blades shall have equal tooth-pitch and the teeth in the saw blades shall have front faces or edges so oriented that the blades are pressed together by shear forces. This i5 achieved in that the teeth in the left blade (seen in the sawing direction) has a front directed towards and acting to the right a-t the grip in the wood and that the teeth in the right blade has a front directed to and acting to the left at the grip in the wood.
The active cutting tools thus can steer the cut to the right or the left. A similar steering effect can be achieved by the present invention by an appropriate distri-bution of th~ heating of the saw cut so as to facilitate cutting by one or the other of the blades. This is done by introducing a third electrical system and a varied voltage feeding to the two saw blades. The afore-mentioned right/
left forces are influenced by the above~mentioned electrical voltage feeding due to the changed cutting resistance created by the heating.
THE DRAWING
The objects and advantages of the invention will become apparent from the following detailed description of preferred .~
~mbodiments thereof, in connectlon with the accompanying drawings in which like numera`ls delsingate like elements, ~nd in which:
Figure 1 is a side elevational view of a cutting tool of the type employing axially~adjacent circular ~aw bladPs, with a portion of one blade broken away to reveal electric insulation betw~en the blades, ~nd with electric curxent being depicted in broken lines within the workpiece being cut;
Figure 2 is a cros~-sectional view through a workpiece, depicting the front of the cutting tool o Figure 1;
Figure 3 is a ~chematic ~ide view of the ou~ting tool depicting an alternate type of electric circuit connected thereto;
Figure 4 is a schematic view of a cutting tool installation with still another type of electric circuit connected thereto;
Figure 5 is a ~ide elevational view, partly in longitu~; n~l section, of a cutting tool installation a¢cording to the pre~ent inYentiOn;
Figure 6 is a side elevational view of another type of cutting tool according to the present invention;
Figure 7 i~ a front view of a fuxther type of cutting tool according to the present invention; and Figur~ 8 is a cro~s-sectional view taken along line A-A of Figure 4~
DETAILED DESCRIPTION OF PP~E~ERRED
EMBODIMENTS OF ~HE lNV l~:N l ION
Aa~ ~odiment of the inventi.on pertait~ g to sawblades i~ showrl in Figure 1. The sa~blades 1 and ~ are mutually isolated electl-ical].y from each o~her by a sui~able electrical insulation material 5, ~lUS, the ~e~uen~ial teeth 6, 7 are el4!ctrically isola~ed from aach other. The blades 1 and 2 are provided with opposit~ el~ctrical polari ty by mearls of a circuit which includes a power source 8. When the tooth~tips penetrate the workpiece 4 there will occa3r a strong electric field between sequential wedge-shaped teeth , i ~ e O, in the general direction of cutting, as depicted in Figure 1. The e:Lectrical current lies along the ~hortest path be~ween mutually ~earby teeth with opposite polarity. From the figure it is also clear that the electrically-gerlerate~l heat production will be greatest i ~~iately adjacent the wedge tips.
If the material in t:he wc~rkpiece has a high electrical conductivity, for e2cample metal, the heating current is pro-duced by ohmic resistance, from a ~uitable DC-source or AC-~ource with low fre~uerlcy~. When working on material with low conductivity, for exampla, wood, plastios, etc,., the energy is applied dielectrically with hi~ frequency. The heat i~
co~centxated in t:he cutting area of the material partly due to the sharp w~dges and partly because the dis tanc~ be~ween elac-2 5 trically cooperat:ing teeth is short O ~reas wi th a greater distance from the wedges thus will not be even slightly heatedO
~ igures 3, 4, and 5 ~how variou~ embodLment~ wherein it is po~ible to balanre or mutually vary ~he heat ~roduc-tion at the two ~roups of th8 wedge teethu Thi6 î6 done by introducing a third electric pole 3A grounded to the machlne as shown in ~igure 3.
Fiyures 4 and S ~how that a mid-part 3 containing the isolation layer 5 can be arranged as a third pole. In Figures 4 and 5, an embodlment of a circular saw i~ ~hown in which a 3-pole ~y~tem wi~h controllable voltaye be~ween the poles i8 u~edO ~hi~ voltage control i~ ad~usted in respon~e to ~he shear force variation between the right-hand t~eth 6 and ~eft-hand ~eeth 7, or by means of a ~aw-stearing con~.rol program of a c~ er.
A~ ~hown in Figure 4, the poles 1, 2, and 3 have been electrically isolated from each other in that the conductor or pole 3 lies ~etween the ~urrounding ~awing poles 1 and 2 and is, in turn, ~urrounded by the insulating layer.5. ~he manner in which this isolation is achieved and how an eleo-trical outer csntact i~ arran~d wi~h ~he poles is demonstrated by Figure 5, which will be descxibed later in detail.
The saw blades 1 and 2 ~re driven ~ynchronously b~
~ motor 11 ~Fig. 4). This occurs via a drive shaft 12, a pair of chain tX~n~m;~sions 13 and 14, and a pair of gear ~y~tem~ 15-18. At least two of ~he gears 16, 18 ~re elec-trically i~olatecl from the ~awing units 1 ~nd 2, a~ depict~d ; in Figure 5~
Even if ~he ~w blades are driven synchronously, a relatively and ~mall internal r~se-wheeling will be allowed and facilitate~r This is done by covering one of the contact surfaces between the elec:trodes with ~uitable grease ~9 as to create unequal she,aring forces of the teeth in each chain-transmi~sion~ ~he g~ears 15 and 17, and their bearingæ are mounted to the machine ~rame:by two conven~ional electrical pulling-force ~en~ors l9a and l9b. These sen~ors ~re responsive to the shearing forc:es on the blades and are connected electrically in serie~ and ~ensitivity-ad~usted ~o l:hat the resllltant ~;ignal voltage will be zero when the shearing-forces on the blades 1, 2 are equal. The needed amplitude for the above-mentioned free-wheeling is determined by the elasticity of ~he force sensors and can, with suitable choice of sensors, be }cept ~Tery ~mall.
The manner in which this foxce-difference signal can be used to restsre the force differences to zero or nearly zero is depicted in the lower part of Figure 4. That is, an ideal straight sawing direction occurs in the absence of unequal side forces on the saw blade~. In the event that unbalanced forces occur/ the result electrical signal influences, via a bi-polar relay 20 (functioning as an electro-magnetic ~witch), the dire~tion of the xotation of a ~ervo-motor 210 The output ~haft of the motor turn~ ~he mid-electrode 24 of a vaxi~ble double capacitor 24~ (6ee also Fig. 8) which electrically i~ isola~e~ from the ~ervo-motor.
~'~g'~
The mid-electrode is connected to ~e mid-pole 3 in the saw ~lade sy~tem. The inductor is inductively coupled to an adjuskable power-generator. As the~ output shaft o~ ~he motor 21 turns, ~he relative heating of ~:he blades 1~ 2 is changed depending upon the d.irection and extent of the rotationO
The vuter el~ctrodes 22 and 23 of the double capacitor are connected via sliding contacts 27 and 28 (Fig. 5~ to the ~aw blada units 1 and 2, respectively. The connection is so chosen that the voltage-unh~l~nres in the 3-electxode ~ystem are creating unbalanced heating effectæ in the blades 1, 2 to rebalance the shearing forces imposed upon the blades. That is, a~ the blades are subjected to unequal shearing orces which could ~urn the saw from its intended direction, the sensing system l9a, l9b, 20~ 21 varies ~he heating of the blades to equalize the ~hear forces and prevent ~uch misdirec-tion.
By ~uitable forming of the outer electrodes 23 f 22 of ~he double capacitor 24A in Figure 4 ~hown in the cross-~ection of Figure 8), a~d/or its mid-electrode 24 (shaded in Fig~ 8), the total capacitance of the ~ystem can be kept constant.
When constructing a self-oscillating power generator this achieves a pract.~cally constant generator frequency.
It is also possible to vary the conditions at the relay 20 in order to create a de~ired st~ering ~f ~he bladesO
This is achieved by connecting a bridge circuit 26A to vne side of the relay 20. An adjustable resistor 26 of the grounded ._ ~
electrical ~ridge-system 26A will influence the voltage of relays in the bridge circuit. The bridge voltage can be deviated from a zero value to ~n arbitrary plu8 or minus value, The ~ervo~sy~t~m automatic,ally adjusts in accordance with the characteristics of the relay 20 to achieve a desired hear force distribution ~mong the blades, i.e~, an assymetrical cutting relationship, to achi~ve curved sawing, compensation of an unequal teeth wear, etc.
In Figure 5 there are depicted the 3 pole s~stem 1, 2, and 3, its outer electxical con~act system 27, ~8, and 29~
and the two driving gears 16 and 18. For clarity, the 3 pole system is ~eparated. Furthex, only one ~ection part of the ~w baldes with its inclined teeth ha~ been shown. These detail~ are also discussed in the above-mentioned Swedish Patent Application 7905412-8. Nut~ 3U-33 press the saw blades 1 and 2 7 and the gears 16 and 18 to ~heir ~xial working positions. The B2W blades travel along ~uitably fo.rmed splines 34 and 35, to achieve a desired mutually angled relation~hip.
In a normal position, he ~aw blades are press~d together and ~he teeth fronts are superimpo~ed, ~ee the ~roken lines at 6 and 7 in Figure 5. The axial outer parts of the rotary system ~ecure ~he bearings 36 and 37. These bearings have been elec-trically isolated ~rom the electric circuitr~ by means of convention~l isslating rings 38 and 3~. The rings al~o have ~ontact with flanges or shoulders of ~he shaft to pro~id~ the ~y~tem with an axial ~tability.
9 _ By ~uitably ~le6igning the ~ ec:txis~ yBtell) 9 no elecltrical voltage of the ~w blas~e~ relat.iv~3 t~ the çlurroundin~ w~ 11 occur ~mder bala~c~d c:osldition~ c~ the elec rical bridge 26A.
Alternatively, h: UV~r~ t:he conTIectia~g contact 40 of ~he i~ducts:~r 25 c~n be grounded (~ig. 41. Then, the use~ul electri;:al power ~rom the gener~tor will be concen~
trat~d only at tl-e cutting ar0a~.
Another po~ible ~lter~ative ~not ~hown) of the invention ~Dlve~ connel:ting the blade and æhaft units 1, 2 arld 3 of Figu~e 4 directly to one another :Eor common rotation by a directly-coupled m~tor ~uch as motor 11).
The two force~ or~, l9a ~nd l9b ~ould be replaced by a ~ingle forc~ en~0r, whi~h i~ D~unted on the ~rame for measuring axia7 pre~sure on the shaft-~ystem. The part~
1, 2, 3 of the ~y~tem wDuld ~e ~rr~nged wi~ a smaller axial ¢learance and initially bia~ed with ~ ~onst;~nt ~orc:e in the ~xial direction toward~ tlhe forceo~ sor :L9 by a 5pring or axam~le . Thi~ perm~ts a ~naller overa~ 1 bla~le-thiekne~s ~t a 2 0 maintA i net'l ~tif fne1sæ .
A~ embo~ t of the i~v~3nltis~n depiclted :i n Figure 6 ~volves ~ double-wedge lA, 2~ ~o be u~cd fc)r plarling, aaill~ng, vene~ring c:uttirlg, ~tco ~ o ~ wh~n ~n~ller amourlt~
~e!7g~ Urf~!lC~ lay~r~ o~ ~e worlcpie~a are to ~ r~v~d.
q~o w~dge par~ 1~ 2nd 2~ ~re ~Lrranged to :Eorm a ~ gle c~utt~ng unit ~ut c:an be~ tiv~ly dli~pla~d irl a direction ~ 19 ... ... ... ..... . .. . . . .... .. . . . . . .. .. ..... . . .. . ..
pexpendic~ r or para~ co ~he ¢u~ing ~liTeC:tiOn to ve de~ir~d GUtting ~fe~:~s, for example by c , ~n~ating ~or cutter ~Dear or varying o f ~he ~ex~ure in the workpi~ce, etc. The wedge parts 1~ 2A are elec~r.ically ~:nsul~ated by lthe in~ulating material 5 ~o achie!ve a ::urre:nt acros~ their cutting tips in lthe afore-di~cu~ed ma~er.
Figure 7 ~hows ~ln emborl; ent of the invention for achieving dufit-free c:utting oP a ~aterial. The wedge~halves 1 B and 2B c:an be s31isplaced r~31atively to each othex in direction~ perpendicular or parallel to the c:utting dixec-tion. Al~o, the cutters ~an be vi~.rated wi~hout a ~ignifioant lo~s in ~ide-~tability~ since the ~oncen rated heat production will decxea~e ~he cutting w~rk and thu8 decrea~e the ~ide force effec~s.
In Fiyure~ 1 3 and ~igure~ 6 7~ the electrical power-g~erator 8 ha~ ~t been d~sc~ibed in detail ~ince it is of well-known constru~tion, The ~o~ 6 of the inven~ion depicted and desrribed herein ~re only e~emplary7 ~hey mu~t be ~een as examples which may b~ ~odified and ~h~ cannot be seen a~ limiting ~he ~cope of the i~ventlon. ~he ~ctual con~tru~tion o the particul~r e~bod~m~nt~ may be diff~rent ~nd the different ~pplic~tion area~ for cutting tools ac~ording to ~h~ invention ~re va6t.
~xampleQ o~ other applic~tion ~reas are ~etal ~orking, ~edi~ urgery~ cu~ting of ~eep-frozen pxoduct~, ~ur~ce grinding, ~tc.
'11 --
The saw blades shall have equal tooth-pitch and the teeth in the saw blades shall have front faces or edges so oriented that the blades are pressed together by shear forces. This i5 achieved in that the teeth in the left blade (seen in the sawing direction) has a front directed towards and acting to the right a-t the grip in the wood and that the teeth in the right blade has a front directed to and acting to the left at the grip in the wood.
The active cutting tools thus can steer the cut to the right or the left. A similar steering effect can be achieved by the present invention by an appropriate distri-bution of th~ heating of the saw cut so as to facilitate cutting by one or the other of the blades. This is done by introducing a third electrical system and a varied voltage feeding to the two saw blades. The afore-mentioned right/
left forces are influenced by the above~mentioned electrical voltage feeding due to the changed cutting resistance created by the heating.
THE DRAWING
The objects and advantages of the invention will become apparent from the following detailed description of preferred .~
~mbodiments thereof, in connectlon with the accompanying drawings in which like numera`ls delsingate like elements, ~nd in which:
Figure 1 is a side elevational view of a cutting tool of the type employing axially~adjacent circular ~aw bladPs, with a portion of one blade broken away to reveal electric insulation betw~en the blades, ~nd with electric curxent being depicted in broken lines within the workpiece being cut;
Figure 2 is a cros~-sectional view through a workpiece, depicting the front of the cutting tool o Figure 1;
Figure 3 is a ~chematic ~ide view of the ou~ting tool depicting an alternate type of electric circuit connected thereto;
Figure 4 is a schematic view of a cutting tool installation with still another type of electric circuit connected thereto;
Figure 5 is a ~ide elevational view, partly in longitu~; n~l section, of a cutting tool installation a¢cording to the pre~ent inYentiOn;
Figure 6 is a side elevational view of another type of cutting tool according to the present invention;
Figure 7 i~ a front view of a fuxther type of cutting tool according to the present invention; and Figur~ 8 is a cro~s-sectional view taken along line A-A of Figure 4~
DETAILED DESCRIPTION OF PP~E~ERRED
EMBODIMENTS OF ~HE lNV l~:N l ION
Aa~ ~odiment of the inventi.on pertait~ g to sawblades i~ showrl in Figure 1. The sa~blades 1 and ~ are mutually isolated electl-ical].y from each o~her by a sui~able electrical insulation material 5, ~lUS, the ~e~uen~ial teeth 6, 7 are el4!ctrically isola~ed from aach other. The blades 1 and 2 are provided with opposit~ el~ctrical polari ty by mearls of a circuit which includes a power source 8. When the tooth~tips penetrate the workpiece 4 there will occa3r a strong electric field between sequential wedge-shaped teeth , i ~ e O, in the general direction of cutting, as depicted in Figure 1. The e:Lectrical current lies along the ~hortest path be~ween mutually ~earby teeth with opposite polarity. From the figure it is also clear that the electrically-gerlerate~l heat production will be greatest i ~~iately adjacent the wedge tips.
If the material in t:he wc~rkpiece has a high electrical conductivity, for e2cample metal, the heating current is pro-duced by ohmic resistance, from a ~uitable DC-source or AC-~ource with low fre~uerlcy~. When working on material with low conductivity, for exampla, wood, plastios, etc,., the energy is applied dielectrically with hi~ frequency. The heat i~
co~centxated in t:he cutting area of the material partly due to the sharp w~dges and partly because the dis tanc~ be~ween elac-2 5 trically cooperat:ing teeth is short O ~reas wi th a greater distance from the wedges thus will not be even slightly heatedO
~ igures 3, 4, and 5 ~how variou~ embodLment~ wherein it is po~ible to balanre or mutually vary ~he heat ~roduc-tion at the two ~roups of th8 wedge teethu Thi6 î6 done by introducing a third electric pole 3A grounded to the machlne as shown in ~igure 3.
Fiyures 4 and S ~how that a mid-part 3 containing the isolation layer 5 can be arranged as a third pole. In Figures 4 and 5, an embodlment of a circular saw i~ ~hown in which a 3-pole ~y~tem wi~h controllable voltaye be~ween the poles i8 u~edO ~hi~ voltage control i~ ad~usted in respon~e to ~he shear force variation between the right-hand t~eth 6 and ~eft-hand ~eeth 7, or by means of a ~aw-stearing con~.rol program of a c~ er.
A~ ~hown in Figure 4, the poles 1, 2, and 3 have been electrically isolated from each other in that the conductor or pole 3 lies ~etween the ~urrounding ~awing poles 1 and 2 and is, in turn, ~urrounded by the insulating layer.5. ~he manner in which this isolation is achieved and how an eleo-trical outer csntact i~ arran~d wi~h ~he poles is demonstrated by Figure 5, which will be descxibed later in detail.
The saw blades 1 and 2 ~re driven ~ynchronously b~
~ motor 11 ~Fig. 4). This occurs via a drive shaft 12, a pair of chain tX~n~m;~sions 13 and 14, and a pair of gear ~y~tem~ 15-18. At least two of ~he gears 16, 18 ~re elec-trically i~olatecl from the ~awing units 1 ~nd 2, a~ depict~d ; in Figure 5~
Even if ~he ~w blades are driven synchronously, a relatively and ~mall internal r~se-wheeling will be allowed and facilitate~r This is done by covering one of the contact surfaces between the elec:trodes with ~uitable grease ~9 as to create unequal she,aring forces of the teeth in each chain-transmi~sion~ ~he g~ears 15 and 17, and their bearingæ are mounted to the machine ~rame:by two conven~ional electrical pulling-force ~en~ors l9a and l9b. These sen~ors ~re responsive to the shearing forc:es on the blades and are connected electrically in serie~ and ~ensitivity-ad~usted ~o l:hat the resllltant ~;ignal voltage will be zero when the shearing-forces on the blades 1, 2 are equal. The needed amplitude for the above-mentioned free-wheeling is determined by the elasticity of ~he force sensors and can, with suitable choice of sensors, be }cept ~Tery ~mall.
The manner in which this foxce-difference signal can be used to restsre the force differences to zero or nearly zero is depicted in the lower part of Figure 4. That is, an ideal straight sawing direction occurs in the absence of unequal side forces on the saw blade~. In the event that unbalanced forces occur/ the result electrical signal influences, via a bi-polar relay 20 (functioning as an electro-magnetic ~witch), the dire~tion of the xotation of a ~ervo-motor 210 The output ~haft of the motor turn~ ~he mid-electrode 24 of a vaxi~ble double capacitor 24~ (6ee also Fig. 8) which electrically i~ isola~e~ from the ~ervo-motor.
~'~g'~
The mid-electrode is connected to ~e mid-pole 3 in the saw ~lade sy~tem. The inductor is inductively coupled to an adjuskable power-generator. As the~ output shaft o~ ~he motor 21 turns, ~he relative heating of ~:he blades 1~ 2 is changed depending upon the d.irection and extent of the rotationO
The vuter el~ctrodes 22 and 23 of the double capacitor are connected via sliding contacts 27 and 28 (Fig. 5~ to the ~aw blada units 1 and 2, respectively. The connection is so chosen that the voltage-unh~l~nres in the 3-electxode ~ystem are creating unbalanced heating effectæ in the blades 1, 2 to rebalance the shearing forces imposed upon the blades. That is, a~ the blades are subjected to unequal shearing orces which could ~urn the saw from its intended direction, the sensing system l9a, l9b, 20~ 21 varies ~he heating of the blades to equalize the ~hear forces and prevent ~uch misdirec-tion.
By ~uitable forming of the outer electrodes 23 f 22 of ~he double capacitor 24A in Figure 4 ~hown in the cross-~ection of Figure 8), a~d/or its mid-electrode 24 (shaded in Fig~ 8), the total capacitance of the ~ystem can be kept constant.
When constructing a self-oscillating power generator this achieves a pract.~cally constant generator frequency.
It is also possible to vary the conditions at the relay 20 in order to create a de~ired st~ering ~f ~he bladesO
This is achieved by connecting a bridge circuit 26A to vne side of the relay 20. An adjustable resistor 26 of the grounded ._ ~
electrical ~ridge-system 26A will influence the voltage of relays in the bridge circuit. The bridge voltage can be deviated from a zero value to ~n arbitrary plu8 or minus value, The ~ervo~sy~t~m automatic,ally adjusts in accordance with the characteristics of the relay 20 to achieve a desired hear force distribution ~mong the blades, i.e~, an assymetrical cutting relationship, to achi~ve curved sawing, compensation of an unequal teeth wear, etc.
In Figure 5 there are depicted the 3 pole s~stem 1, 2, and 3, its outer electxical con~act system 27, ~8, and 29~
and the two driving gears 16 and 18. For clarity, the 3 pole system is ~eparated. Furthex, only one ~ection part of the ~w baldes with its inclined teeth ha~ been shown. These detail~ are also discussed in the above-mentioned Swedish Patent Application 7905412-8. Nut~ 3U-33 press the saw blades 1 and 2 7 and the gears 16 and 18 to ~heir ~xial working positions. The B2W blades travel along ~uitably fo.rmed splines 34 and 35, to achieve a desired mutually angled relation~hip.
In a normal position, he ~aw blades are press~d together and ~he teeth fronts are superimpo~ed, ~ee the ~roken lines at 6 and 7 in Figure 5. The axial outer parts of the rotary system ~ecure ~he bearings 36 and 37. These bearings have been elec-trically isolated ~rom the electric circuitr~ by means of convention~l isslating rings 38 and 3~. The rings al~o have ~ontact with flanges or shoulders of ~he shaft to pro~id~ the ~y~tem with an axial ~tability.
9 _ By ~uitably ~le6igning the ~ ec:txis~ yBtell) 9 no elecltrical voltage of the ~w blas~e~ relat.iv~3 t~ the çlurroundin~ w~ 11 occur ~mder bala~c~d c:osldition~ c~ the elec rical bridge 26A.
Alternatively, h: UV~r~ t:he conTIectia~g contact 40 of ~he i~ducts:~r 25 c~n be grounded (~ig. 41. Then, the use~ul electri;:al power ~rom the gener~tor will be concen~
trat~d only at tl-e cutting ar0a~.
Another po~ible ~lter~ative ~not ~hown) of the invention ~Dlve~ connel:ting the blade and æhaft units 1, 2 arld 3 of Figu~e 4 directly to one another :Eor common rotation by a directly-coupled m~tor ~uch as motor 11).
The two force~ or~, l9a ~nd l9b ~ould be replaced by a ~ingle forc~ en~0r, whi~h i~ D~unted on the ~rame for measuring axia7 pre~sure on the shaft-~ystem. The part~
1, 2, 3 of the ~y~tem wDuld ~e ~rr~nged wi~ a smaller axial ¢learance and initially bia~ed with ~ ~onst;~nt ~orc:e in the ~xial direction toward~ tlhe forceo~ sor :L9 by a 5pring or axam~le . Thi~ perm~ts a ~naller overa~ 1 bla~le-thiekne~s ~t a 2 0 maintA i net'l ~tif fne1sæ .
A~ embo~ t of the i~v~3nltis~n depiclted :i n Figure 6 ~volves ~ double-wedge lA, 2~ ~o be u~cd fc)r plarling, aaill~ng, vene~ring c:uttirlg, ~tco ~ o ~ wh~n ~n~ller amourlt~
~e!7g~ Urf~!lC~ lay~r~ o~ ~e worlcpie~a are to ~ r~v~d.
q~o w~dge par~ 1~ 2nd 2~ ~re ~Lrranged to :Eorm a ~ gle c~utt~ng unit ~ut c:an be~ tiv~ly dli~pla~d irl a direction ~ 19 ... ... ... ..... . .. . . . .... .. . . . . . .. .. ..... . . .. . ..
pexpendic~ r or para~ co ~he ¢u~ing ~liTeC:tiOn to ve de~ir~d GUtting ~fe~:~s, for example by c , ~n~ating ~or cutter ~Dear or varying o f ~he ~ex~ure in the workpi~ce, etc. The wedge parts 1~ 2A are elec~r.ically ~:nsul~ated by lthe in~ulating material 5 ~o achie!ve a ::urre:nt acros~ their cutting tips in lthe afore-di~cu~ed ma~er.
Figure 7 ~hows ~ln emborl; ent of the invention for achieving dufit-free c:utting oP a ~aterial. The wedge~halves 1 B and 2B c:an be s31isplaced r~31atively to each othex in direction~ perpendicular or parallel to the c:utting dixec-tion. Al~o, the cutters ~an be vi~.rated wi~hout a ~ignifioant lo~s in ~ide-~tability~ since the ~oncen rated heat production will decxea~e ~he cutting w~rk and thu8 decrea~e the ~ide force effec~s.
In Fiyure~ 1 3 and ~igure~ 6 7~ the electrical power-g~erator 8 ha~ ~t been d~sc~ibed in detail ~ince it is of well-known constru~tion, The ~o~ 6 of the inven~ion depicted and desrribed herein ~re only e~emplary7 ~hey mu~t be ~een as examples which may b~ ~odified and ~h~ cannot be seen a~ limiting ~he ~cope of the i~ventlon. ~he ~ctual con~tru~tion o the particul~r e~bod~m~nt~ may be diff~rent ~nd the different ~pplic~tion area~ for cutting tools ac~ording to ~h~ invention ~re va6t.
~xampleQ o~ other applic~tion ~reas are ~etal ~orking, ~edi~ urgery~ cu~ting of ~eep-frozen pxoduct~, ~ur~ce grinding, ~tc.
'11 --
Claims (10)
1. A cutting tool comprising at least two spaced cutting edges, means electrically isolating said cutting edges from each other, and means connecting said cutting edges to an electrical voltage source for creating a current between the cutting edges and within a workpiece being cut, to heat the workpiece at the cutting area.
2. A cutting tool according to claim 1, wherein each cutting edge comprises a tooth of a blade, each blade having a plurality of said teeth, the teeth of one blade being offset from the teeth of the other blade, said blades being electrically isolated from each other.
3. A cutting tool according to claim 2, wherein each cutter comprises a circular saw.
4. A cutting tool according to claim 1, wherein each cutting edge is of wedge-shaped configuration.
5. A cutting tool according to claim 1 including an electrical circuitry connected to said voltage source and to a third pole interposed between said cutting edges to induce a current flow therebetween.
6. A cutting tool according to claim 1 including means for varying the voltage across said cutting edges.
7. A cutting tool according to claim 2, wherein said blades are configured in mirror image to produce equally opposing side forces which press said blades together.
8. A cutting tool according to claim 1, wherein said cutting edges comprise a pair of wedges which are oriented to define a single unit.
9. A cutting tool according to claim 8, wherein said wedges are relatively displaceable directions perpendicular to the direction of cut.
10. A cutting tool according to claim 8, wherein said wedges are relatively displaceable parallel to the cutting direction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000402068A CA1191428A (en) | 1982-04-30 | 1982-04-30 | Cutting tool having means for heating a workpiece |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000402068A CA1191428A (en) | 1982-04-30 | 1982-04-30 | Cutting tool having means for heating a workpiece |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1191428A true CA1191428A (en) | 1985-08-06 |
Family
ID=4122690
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000402068A Expired CA1191428A (en) | 1982-04-30 | 1982-04-30 | Cutting tool having means for heating a workpiece |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1191428A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2153925A1 (en) | 2008-08-06 | 2010-02-17 | United Technologies Corporation | Machining process and cutting tool |
-
1982
- 1982-04-30 CA CA000402068A patent/CA1191428A/en not_active Expired
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2153925A1 (en) | 2008-08-06 | 2010-02-17 | United Technologies Corporation | Machining process and cutting tool |
| US7736102B2 (en) | 2008-08-06 | 2010-06-15 | United Technologies Corporation | Control of white-etched layer during machining |
| US7805824B2 (en) | 2008-08-06 | 2010-10-05 | United Technologies Corporation | Control of white-etched layer during machining |
| US7827661B2 (en) | 2008-08-06 | 2010-11-09 | United Technologies Corporation | Control of white-etched layer during machining |
| EP2484472A1 (en) * | 2008-08-06 | 2012-08-08 | United Technologies Corporation | Machining process and cutting tool |
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| MKEX | Expiry | ||
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Effective date: 20020806 |