GB2337713A

GB2337713A - Sharpening chain saws.

Info

Publication number: GB2337713A
Application number: GB9912165A
Authority: GB
Inventors: Christopher Lehan
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-05-27
Filing date: 1999-05-25
Publication date: 1999-12-01
Anticipated expiration: 2019-05-25
Also published as: GB2337713B; GB9912165D0; GB9811315D0

Abstract

In equipment for sharpening a chain whilst on a chain saw a chain guide the guide is held and the grinding wheel is set to the correct angle for the first tooth to be sharpened, the grinding wheel is lowered into contact with the tooth and rotated until the correct degree of sharpening is attained, the wheel is then raised out of contact with the tooth, the chain is moved a pre-set distance until the next tooth is in position beneath the grinding wheel and the angle of the grinding wheel is changed to the second pre-set angle so as to be in the correct position and orientation for the sharpening this tooth and the process repeated.

Description

2337713 1 - Sharpening Device 9-1 The present invention relates to a

method and equipment for sharpenim, chain saws, ZZ, more particularly it relates to a method and equipment for sharpening chain saws xvithoui the need to remove the chain from the chain saw.

The metal cutting teeth on typical chains in chain saws have their cutting edge at an c 1) I'D an-le to the cuttin- direction of the chain, so that when they are sharpened the correct c, 0 angle of sharpening in both the vertical and horizontal planes needs to be formed as v,c11 as the correct depth of cut Chains can be sharpened by removing tile chain fronfl its guide, holding it in a vice or other holder and sharpening the teeth using a file whIch grinds a kay the cutting edge until it is sharp. The alternate teeth on the chain sa" are at a difTerent an-le to cuttin- line of the sak which makes it difficult to obtain a constant cuttin- angle To overcome th-s difficulty and to achieve a more consistent cut, rigs ha-ve been devised in which the chain is held in position and the file Is held 11,1 zy the ric, a so that it can offiv i-nove in a pre-set angle to the chain Rigs have also been devised in which a grinding wheel is lowered onto the chain at a pre-set angle to sharpen the teeth 2,3 In all these methods the chain has to he undone and placed in the rig which makes thern awkward and incon,,.,enierit to use on 1te.

In these methods the chain ha to be at least partly removed from its gulde and 11 is difficult acli'le c the same depth of' cut and degree of sharpness oil each tooth AllY ilicolisistelTic' in sharpness, depth or angle ofthe cutting edge of the teeth will lead to Q - the chain saw not cuttin(y in a straight line which will cause difficulties in use 1 have now devised improved equipment and a method for sharpening the Chaills 011 chain a s 2 - According to the invention there is provided equipment for sharpening the chain on a chain saw, which equipment comprises a holding means for holding the chain guide, a rotatable grinding wheel which. on rotation, is able to sharpen the teeth on a chain 011 the chain -,ulde, and a chain moving means which is able to move the chain a pre-set 1 distance. in which equipment the grinding wheel able to be set at a first pre-set angle W - to the edge of a tooth on the chain and in which there is a changing means able to chant,e thi., ari,,[e to a second pre-set an-le and a means for lowering the grinding wheel into contact with a chain on a chain--- Uideheld in the holding means.

In use, a chain guide, on which the chain to sharpened is mounted, is held in the holdim, means and the first pre-set angle of the grinding wheel is set to the correct amfle for the first tooth to he sharpened, the grinding, wheel is lowered into contact with the tooth and rotated until the correct degree of sharpening is attained, the wheel is then raised out of contact with the tooth. the chain moving means operated to move the chain the pre-set distance until the next tooth is in position beneath the grIndin,' v,heel and the an de of the grinding wheel is changed to the second pre-set angle so as to be Iii the correct position and orientation for tile sharpening this tooth and the process repeated.

The rotatable grinding wheel can be made of any conventional metal sharpeni 11.

1 ing material such as Carborundum etc. and can be rotated by means of a handle connected to the wheel, Preferably., in use, the pressure of the grinding wheel oil the tooth being sharpened is constant for each tooth so that the same number of turns of the wheel achieves the same degree of sharpening for each tooth. This pressure can be pre-set tislii,-, the weight of the wheel with, If necessary a spring means controlling the Pressure Looking down vertically on the chain, the teeth on the chain are at an an- le In the Z.) horizontal plane to the line of cut of the chain. with the alternate teeth bein- disposed at alternate angles to this line but in opposite direction, The first and second pre-set angles of the grinding wheel are set accordingly.

t c) The movement of the grinding wheel preferably controlled by, a earn act 1 ing on an actuating bar so that, as the cam rotates. the grinding wheel is raised and lowered. The earn can also act on the rneans for movine the chain c-(, via a push-il(' rod etc so that the ralsincy and lowerincy of the grinding wheel is synchronised and co- ordinated with W the chain moving means by means of adjusters so that, for any particular chain the C parameters can be set for the required distance of movement of the chain so that the teeth are in position as the grinding wheel ls lowered into contact.

Z:7 The (Yrliidlti,, wheel is preferably turned by hand so that the rotation of the grinding n ' i -- W wheel is linked to the raising and lowerin. of the arinding wheel, the change of angle 1 t) Z:- C> of the grinding wheel and movement of the chain to give a coordinated and i 5 s,iiclii-oni,ed operation which automatically will cause the chain teeth to be sharpened to the requisite arnount and angle by the operation of turning the grinding wheel.

1 - Flo 1 is a side view of the sharpening device, Fi (1, 2 is a vertical view, Fi shows the pivoting of the grindino wheel and Z) Fig, -4 the chain moving means A chain -u- Gr'nd"n(, wheel g ide ( 1) has a chain teeth (2) mounted on it. 1 1 C, (.3) supported by, supports (5) is able to be raised and lowered by operation of cam (4) so that the can be in contact with a tooth on the chain in its lowered position and ralsed ak-a from the tooth in the raised position There is a pusher rod (6) which can contact the back of a tooth and push the chain alon- the chain gulde ( 1) The pusher is operated by, cam (4). This is shown in more detail in fi-. (4) The orind' 1- 1 1110 wheel (,) is turned by handle (6) and turning the grinding wheel (3) causes the caril - 4 (4) to rotate and the grinding, wheel to be raised and lowered and the chain pushed alone the -1lide ( 1 t 1:1 Referrinu to fi- The orindim, wheel (3) is driven by driving wheel (8) which operates by, mearis of a friction drl-, e and is driven by belt (9) There is all adjusting means ( 10) which can adjust the height the grinding wheel is raised and lowered Referring to flu, 3) The grindin. wheel (3) which is driven by driving wheel (8) I's able t> io pivot about pivot (1 1) to the second position shown by the dotted lilies. As call be seen, tile friction drive mechanism will turn the grinding wheel (3) In both positions Referring to fi- 4 The pusher rod (6) is operated by cam (4) acting, oil the rod and causing It to push he tooth (2) as shox.:n Tile pusher rod (6) has a si)r'ril(:, loaded end causes it to mo've out of' the wav when it has pushed the tooth the pre- set is distance In use the device is attached to arid -rips the chain guide (1) arid the an-le of tile grind-Ing wheel (3) is adjusted to give the correct angles of cut to tile teeth (2) on the chain The pusher rod adjustment is adjusted so that.1e chain will moved the requisite distance bs, each action of the pusher rod (6) and the height adjuster ( 10) is adjusted to---Ivethe ri-lit distance of movement of the wheel The wheel (31) is lowered Into coritact x Ith the first tooth and the handle (0) is turned a pre-set nurnber of turns, this causes the required degree of sharperlin- of that tooth, as the handle (6) is continued c W to be turned the action of cam (4) causes the wheel (')) to be lifted from the tooth (2), when the Micel has been removed froin this tooth, the an-le of the is chan-ed h), Illovellicill abolit the P1wt 1) so that the wheel is in the correct angle to sliarpen tile Ilext tooth. -.,lliiuitaileousl-,, the cani causes the ptisher rod (6) to move the chairl unill the llext tooth is belo", the Wheel (3). The continuation of rotation of- \klieel (3) caiise, the wheel to be lowered into contact with the next tooth and the process repeated Trils can be continued unt-11 all the teeth are sharpened.

The device thus provides a simple means of providing uniform and correct sharpening 3 1 _g 1 c ol the Teeth ofa chain swk. whilst the chain Is in position 6

Claims

Claims

Eqiilpiiieiii for sharpenin- the clialn on a chain saw, which equipment comprises 2 ho 1 n -7 Un- means for holdine the chain guide, a rotatable grinding wheel which, of] rotation, is able to sharpen the teeth on a chain on the chain guide, and a chain movino means which is able to move the chain a pre-set distance, in which equipment the (Ti-indin,-, wheel 'Is able to be set at a first pre-set angle to the ed e of a tooth on the 9 chain and in which there is a chan-in- nicans able to chanue this an-le to a second W C" 0 0 pre-set anole and a rneans for lowering the grinding wheel into contact with a chain on a chain---ulde held in the holding means.

Equipment as claimed in claim 1 in which the rotatable - indin-g -lice] is rotated by 1 1 1 1 1 1 P IlleallS, of a liandle connected to the wheel, --,. E(jtjii,3iliciit as claimed in claim 1 or 2 in which there are pressure control Ilicans wherch) the pressure of the grinding, wheel on the tooth being sharpened is constant 1 --- __1 foi cach tooth so that the same number of turns of the wheel achieves the same degree ofsharpening for each tooth 4 E(Itilpiiietii as claimed in claim 3 in which the pressure control mcans is pre-sei,is nu, the wei-lit of the wheel.

51 as claimed in claim 3 or 4 in which the pressure control Illeans incorporates a spring means controlling the pressLire.

0 Equipment as claimed in any one of claims 1 to 5 In which when a chain to be sharpened is positioned in the eqijlpniciit and looking down vertically, oil the chain, the teeth oil tile Chaill are at all an(_xle in the horizontal plane to the line of k:iit of the clialli, the iltei.ii,ile teeth bein- disposed ai alternate angles to this line btli it) opposite 7 - direction and the first and second pre-set an-les of the Orinding wheel are set accordin-ly Equipment as claimed in any one ofelaims 1 to 6 in which the movement of the n1 1 inu on an actuatino bar so that, as the earn Ing, wheel is controlled by a cam act' Z. rotates, the,r-liidin(, wheel is raised and lowered.

0 -1 S E(J1.11pment as claimed in any one ofelairns 1 to 7 in which tile cam also acts on tile means for moviriv the chain so that the raising and lowering of the grinding wheel is synchronised and co-ordinated with the chain movin.. means by means of adjusters so that, for any. particular chain the parameters can be set for the required distance of movernent of the chain so that the teeth are in position as the orinding wheel is lowered into contact, 9 Equipment as claimed in any one of clainis 1 to 8 in which the grinding wheel Is W -- lurned b.,,, hand so that the rotation of' the grindinc, wheel is linked to the raisin- and C" of' the wheel, the clianue of anole of the urindino wheel and 0 C movernent of' the chain to -Ive a co-ordinated and synchronised operation which automatically cause the chain teeth to be sharpened to the requisite amount and anole b the operation of turning the grinding wheel.

t - -- A method for sharpening chains in which the chain guide, on which the chain to sharpened is mounted, is held in a holding means and the first pre-set angle of a (Yrllldlii-,, wheel is set to the correct angle for the first tooth to be sharpened, tile klice! 's lowered vith the tooth and roiated until the correct 1 into contact 1 1 degee of.liarpenitio is attained, the wheel Is then raised out of contact vvith the tooth, and a chaln rneans operated to niove the chain the pre-set distance until the nem tooth 1S In,.)oitioii beneath the,rlndiii,, wheel and the an-le of the wheel Is cliaii,-,c(i to the second pre-set anAe so as to be in the correct position and orientation for the sharpening this tooth and the process repeated 8 - 11 A method as claimed in claim 10 Iin which looking down vertically on the chain, the teeth on the chain are at an an-le in the horizontal plane to the fine of cut of the chain, the alternate teeth being disposed at alternate an-les to this line but in k-)pposi 1 n te direct on and the first and second pre-set angles of the grinding wheel are sei accord 1 12 A rnethod as claimed in clairn 10 or 11 in which the grinding wheel is turned by hand and the rotatIon of the (,rlndin,, wheel is linked to the raising and lox,-erin. of tile C urinding, the change of angle of the grinding wheel and movement of the chaill to,1\,e a co-ordinated and synchronised operation which automatically will cause the chain teeth to be sharpened to the requisite amount and angle by the operation of turnin- ihe grinding wheel 1.5 1 1 Equipment for sharpening a chain on a chain saw as hereinbefore described with reference to the drawings