CA2128893A1 - A tool - Google Patents

Abstract

A tool for tensioning wire, in the form of three flat plates comprising a fixed member (20), a first movable member (30) pivotably connected (40) to the fixed member (20), a link system (70) to link the fixed member (20) and the first movable member (30), the link system (40) consisting of a second movable member (60) pivotally connected to the fixed member (20) by a second pivot (50).
The middle plate has apertures (70a and 50a).

Description

WO 94112320 PCT/N~Z;Y3/0~119 .. ~ :.:,.
'rhe Tool ~ ;2~28~3!313 This inven~ion relates to a tool.

For convenienca only lhe inven~;ion will predominantly be describc(l as~ool for tensionin~ wire to be joine(l, for which the inventit)n m~y 13~
particularly suitable. ~Iowever it is to l)e understood that it is not to be limiled as such. Mor~over;because l;he invention may ~ave many olher .
applications, the prior art and possible applica~ions of the inven~ion tliscusse(l below, are given by way Or example orlly.

There are a number Or known tools usetl for tensioning wire whcn the wirc is l)eing joinell. For examplc, NZ I~atent l~pplication No. 240183 tliscluscs ~
tool which uses a single pivoted lever type mechanism w~lere;n one end of ~h~ wire to be joined is attached to a fitting on a ~Ixe(l membcr or the tool, while the o~her end to ~e joined is grippetl by sliding eollets provi(lc~ on t,he movable lever of the tool. The wire is thus able to bc drawn through n wire re~aining ~le~ice by succcssive movemen& of the mo~a~lc lever, and ~hc cn(i s~cured at th~ wire retaining devicc. With lhis t;ool, ~orce is applic(l to lhc wire retaining device through a simple lever comprising a singlc pivot.
poinl;, with n movable n~ember pi~lol;ing about this poin~. The mecllanil:al allvantage o~ such a tool is thus limited to that of a singlc pivo~ l~vcr mechanislll. The tool may l;her~fore not be sui~al)lc f`or appl~ying D hi~ll ~ension to a wire, unless a sufficiently long arm is provi(led lo givc ~h~
reo,uire(l lever~ge. (~onsequently ~ comp;~cl desi~n mny no~ bc possil)le.

The tool of the prescnt inYention m~y ~)e sui~al)l~ ~or a numbcr ol applications where a mechanical advantage greater thnn th~t Or ~ singrlc lever mechanism is required. For cxample~ the principlc mny ~)e suil;l~)le for use with tools such as tin snips, bolt cutters, hcavy (luty pop rivelor.s, clamping pliers, and crimping tools.

51l~E~STITUT~ S~

~ Q ~4/12~0~ PCT/N~93/0011 Z~L2~3a~913 Conventional ~ools for these applications eithcr cvmprisc a somp~ical~e(l linlcage mechanism to provide the required mechanical advantlg~, or u~se a simple singlo lever mcch~lnism which re(~uires a su~fieicntly Is)n~ Icver arm to obtain the required capacity. ~I~nce, with conventionlll syslems the ~ool is either expensive due to thc complcx linlcag~ me~h~nism, or in the casc of a single lever mechanism, is either limit~d in c'apacity or rc(l~lires a large lever arm.

The tool Or the present invention m~y also ~e suitabl~ for applic~tions where amplification of movement is required with a negative mechanic.ll advantage, that is, a mechanical advantage less than one.

Il is an object of the present invention to address the ~regoing prol)lem~s nr at Icast to provide the pu~lic with a use~ul choicc.

Further a~pects and advantages of the present invention will ~)ccnme apparent from ~he ensuing description which is given bv way o~ e~;~mple only.

~ccording to one aspect of the presen~ invcntion there is providcd a tool ~omprising a i~xed meml)er, a first movable member, said first movable meml)er being pi~otnll.~
connected to said fixed member by a first pivot me2ns provide(l ~)et~veen sais~ f~xed meml)er and said first movable member~

a link means for linking between said fixed member and s.~id rlrst movnl)l~
member, said link means c~mprising at least;

a second movable member, said second moval)le member bein~ pivo~ally connectcd to sai(l filxed mcmber by a secon(l pivot mcans, and SUEISl'lTUTE SIIE~

, . .. . . . ... . .

wO ~4/12320 PC~Tn~z93/~O~l9 2~28~3~3 .... ~ ~...........
means for connec~ing bctwecn said first and secon(l movable mcmbcrs, thc ~rr~ngcmcnt and cs)nslruction l)eing SUS~}l thslt pivotal movemcnt ol saitl second moval)le member about said second pivot me~ns an(l s~ rst movable member about sai(l first pivot means is communicate(l ~)etween said first and second movable members by said linlc mea~ .

According to another aspect of the present invention there is provi(le(l ~
tool su~stantially as described ~bove, whercin saitl link mcsns compriscs at least;

a sccon(l moval)lc member, said second movablc mernber bcing pivot~lly conncctcd to said fi~ced member by ~ secon(l pivot me;~ns, an(l mcans for connccting l~etwcen said first ar d second mo~able mem~)ers, and a ~hird movablc member, said third movable mem~er being pivotnily connected to said fixed member by a third pivot means, and me~ns ~or connecting between said second and third moval)le members, t,he arrangement and construction being such that pivotal movemcn~ of said thi~d movable member a~out said third pivot means an~l said ~ïr~t n~ovable member about said first pivot means if communicat~d bet~v~cn rirst an(l ~hird movahle members by sai~l link mcans.

According to another aspect of the present invention t}lere is provi(lcd ;
~ool substantially as tiescril~ed a~ove, whercin said link means comprises mech:lnic~ll linkage.

~;UBST~UTE SHE

WO 94/12320 PCT/NZ~3/00119 38~93 l~ccor~ling to yet anoth~r aspcct of the prescnt invention thcre is provi(l~d .~too~ su~st~ntially as llescri~e(l al)ove, wherein s~id mech:lJIic.ll link.lgc comprises a single pivo~ pin an(l/or pivotal surfacc.

~c~ording to even ycl another aspecl nf thc l~rc?sent invcnlinn l~)er(! i.s provi(le(l a lool substanlially as (Icscri~e(l ~I)ovc, wllcrcj~sai(l I`irsl n~o-a~)lc member is provide~l with an elongate~l apcriurc, and said ~econ(l pi~
means eomprises a pivot pin which is disposc(l in sai(l aperlur~?.

~ccording to even yet; anol.her aspect of thc present invention ther(~
provided a tool substantially as descri~e~ above, wherein saicl ~ccond movable meml er is provided with an elongate(l aperture, an~l sai(l ~irst pivot means comprises a pivot pin which is disposed in s~id aperture.

According to yet another a~3pect of tlle pre~ent invention there i s provided a tool ~ubstant~ al ly as described above, where said fir~t movable member i~ provided w1th apertures to accoml~date pla~tic emhod1ments which axe di3p~;ed in said aperture .
~ccording to another aspect of the present invention there is provided a methr)rl of moving a movable mem~er o~a tool relative to a ~;~;e(t meml)er Or ~he ~ool, said movat)le member nn(l li.~;e(l Ineml)er ~ in~ pivt)l~ eotln(!cl~
l)y a pivot meml)er conlprising ~he stcl)s o~:

(i) providing a linlcage means ~)et~een sai~l fi:~l?cl and mov~l)le members, and (ii) moving a movable member of sai~l link means su as to cnllse sai(l mo~able mem~er to pivot relative to said f`lxed member.

SUBST~T(JT~ SltlE'r WO 94/12320 ;2~ 3 PCT/NZ9~/001,~9 !
According to yet another aspect of the prescnt invention there is provi~lc(l a method of tensioning or joining wire using a tool substantially .u~
lescril)e(l abov~ comprising th~ s~eps of: -(i) attaching a porlion of thc wire to ~ai~l fl~;cc~ nu~mber, (ii) attaching the othcr en(! ~-1` thc wirc to ~.~i{t mnvat)~e mcm~ r (iii) moving sai(l secon(l movable mcml~er relative to saict fixcd mcml~cr, so tha~, said first mova~ule mem~er moves rcla~ive to sai(l fixed memL)cr, ~hc ratio of angular movement of sai~l first mova~le mcmt~cr rel~l~ive lo thc angular movement of said secon(l movable mcmt)cr, l~cin~ .
predetermined ratio less than one.

With the tool of the present invention as descril)ed above, the provision of the linkage system enables an increase or decrcase in ~he mech.lnic.l:l a(lvantage related to moving the mov~ble member r~lative to the fixesl member, depending on the location of pivot points of thc pivot means tln(l link means. Hence, in the case of arl increased rnechanical ad~anla~c arr~ngement, a greatcr force m~y ~)e applie(l to o~)jccts conncc~ed l)y mc;~
Or the f~xed mennber and movai~le mem~)er, without the rc~uircmcnl l`or ~
large lever as would b~ the c~se with a single lever system, or wilhoul ~ilC
requirement for a complîc~te(l linlcage such as is usc~l with t()ol9 ~UCtl as boil cu~l;crs and tho lilce. A relal ivcly low cosl compnct lool Inay lll~-s i pro(luce(l .

Alternativcly, wi~h a decreascd mechanical advantage arrangemcnt ol' lhc pivot points, amplifïcation of movement may be ob~,aincd.

With the above mechanism, lhe linlt means may comprisc any suital)lc ;UE~5TITUTE SHEIE~

WO 94/12320 PCT/I~I:Z93/00119 212~38~3 me~ns wherel~y a positiv~ or neg~tive mech~nic~ dv~nt~ nl~ly l-~ol)tainecl. For example, tllis may involve ,~1 fluitl me~lium such 1s will~ :
hydraulic system, or may involve a mechanical sys~ern.

ln tlle case Or a niechazlical systcm, tllis may comprisc gear or cam means, or a pin connection wi~h or wi~hout a linl~ rod, o,r-any com~)in:ltion of ~hese.
Furt,hermore, any number of combinations of link mcans may be provi~lc~
to increase the positive or negative mechanical adv~ntage. That is to s~y, a secon(l linl~ means may be provided between the second moval)~e mcml)cr of a first linl~ means, and the fixe(l member. The second link me~ns may opcrate on the same or a diffcrent principle to that of ~he first link means.
~lso, to obtain mechanisms having dif'ferent characteristics, linlc mean.
may be provided between any of the mova~le members that are ablc to move relative to each other. For exampIe, a link means may be provided b~twec th~ first movabIe member and second movable membcr, In the case of a link rod, this may be connected between portions of the flrst movable mem~er and the second mova~le memher l)y pivotal conncction means ~uch as piYot pins or bearing sur~aces. Alternatively, the t,wo movable members m~y be linlced togethcr by ~ singl~ pivot pin and/or pivo~,al surface.

Wi~h thi~ arrangemenl, in order to ol)tain an incrcase in mcc}~anical advantage, the second pivot means may be arran~ccl closer to thc single pivot pin a;nd/or pivotal surfacc than is thc first pivol mcan~.
l~lternatively, to obtain a decrease in mechanical adv;~ntagc for si~uat,i()ll~swhcre the r~tio of angul~r movement of tl-e first mo~l)le mcm~)cr ~o t.l-e second movable mernber relative to the fixe(l meml)er is grc~ r than nnc, SUB8TlTgJTE 81tEET

WO 94/12320 2~ 3893 PCT/NZ93/00119 . ., ' ' ~he first pivot means m~y bc arr~nged closer to the single pivoi ~n-(i/.nr pivot~l surface than is the s~con(l pivot me~ns. O~`course, thc mech.lnic.ll ad~rantage of the link means ~vill be %ero ir the pivot poin~s of thc r~r.sL .ln(l secon(l pivot means coinci(le.

With the tool of the present invention, for use as .1 tcn;sionin~ dcvicc, ~hc rotntion of thc ~lrst and secon(l pi~nt.~l mcml)ers is prc~`cr;ll)ly in lhe ~ llC
scnse relative to the fixed mcmbcr. IIencc, the second pivot rneans sh()ulcl be positioned so that its disl~nce from the first pi~o~ means is less th~n ll-c distance o~}le single piv()t pin and/or pivot~l surface from lhe ~rst pivot means.

Furthermore, the second pivot means may pref`erably be provicle(l on thc fixed member at a position relative to the first pivol, means such th~ ss~id piYot pin and/or pivotal surface pa~se~ through a line through said lirst ancl second pivot means during movement of said,flrs~ and secoald moval)le members. With this arrangement, sliding motion on the pivotal surf~ce may be kept ~o a minimum. The invenSion however is not limited tn this, and with certain arrangements, it may be desirable to have a link menn~;
whereill movement of said second movable member relative to sai(~ ~irst mo~rable mem~er involve~ significant sliding at said pivotal surlacc therebetween. Such an arrangement mny involve n cam sur~lce.

In ~he c~se of the link mcans comprisin~ a coml)ination o~ linlc mcans, thqse may be based on the same principle ancl may be 2~rrangcd witll respective movable members rormecl as plate members which may be stacked side by side, so that a compact design may l)e achiev~(l.
Fur~hermore, optional pivoS points m~y l)e provide~l on th~ rcspccti~c movable members so that the mcchanical n~lvnnt~qge chnracteri~tic.s orthe . 7 SUBSTITUTE 6HEel-Lz~3~393 linlc means may be varic(l as re(luire~l or desired.

In the case of a tool requiring l~rge mov~ment output for a small input mov~ment (negative mechanical ~dvant~ge), this may be descrihed as ror n positi~e mechanical aclv~ntnge tool by considering thc rirst mov.ql-lc meml)er to l)e the inpu~ m~m~)er ~nd tl1e movahle member Or the linkn~o mcans to be ~.he output meml)er.
W1 th the tool o~ the pre~3en~ lnvention, the movab~ e member~ may be provided with an aperture or aper~ures to accomodate plastic embodiments. which are disposed in said aperture to reduce the frictinnal surface contact between the plates. The ~nvention however ls not limited to this, it may be desirable to ha~e plastl c em)~odiments ei ther slde of ~aid movable members .
. .. . .
Further aspects of the present invention vl,i]l becon1e apparent from ~he ensuing description which is given by way of example only an~l with reference to the accomp~nying dr~wings in which:

~: is a schematic diagrnm of a tool according to ~n emhotliment of the present inv~ntion, and E~r~: is a schematic dia~rnm ol another tool according ~o ~n embodiment of the pr~sent invention, wherein the f ~rst moval~le memher i8 the input mcml)er and the sccontl m(lvnblc member is the ou~put memhcr, so th~t opcration of the tool amplif~es the movcment of the first moYable rn~mi)er, nntl ~re 3: is a schematic di~gr~m n~ ~ tool ~ccording to ~nother embodiment of the present invention showing a possiblc coml)in~d linlc~ge mc~ns.

With respcct to figure 1 therc is pro~idc(i ~ tool gcnernlly indic~

SUE3STITUT SHE~ET

WO 94/12320 ~L2a89~ PCT/NZ93/00119 , . . .
arro~v 1. 'l`ile ~ool 1 com,)ris~s a fi~ emL)cl :~ a~ irs~ ms~v~ lc mcmbcr 3. 'l`he f`irsl moval)le Illclnl)-!r 3 is pivolally co~lnec~c(i lo ~h~
mem~)er 2 by means of a pivot pin 4 fixedly ~ttache(l to lhe fi~;cd mcm~cr '~.
Tl~e tool 1 is f`urther l~rovide(~ wilh a linlcage f`ur conne~ling be~vccl- tllerixe~l mem~er ~ an~l the ~ïrst nlova~)le mcm~)er 3. rl`he linlcagc compriscs a second pivot pin 5 rcmova~ly a~ached to t;he lixecl mc~ secon~
movable arm 6 which is pivol~l al~ou~ ~he pivo~ pin ~, and a connectin~ ~in 7 which provides a pivotal connection between the seeond mov~l~le mem~er G ~nd the ;rst movable mem~)er 3. l'lle first moval)le mem~)er 3 is pro~ide(l with an elongated aperture 5~ so ~hat it m~y pivot; aboui ~he pivol pi wi~hou~ interferencc wi~h ~hc pivot pin 5 Fur~hcrmorc a holc 7a in ~h~
first movaL)le mem~er ;3, ~or a(:co~nmocl;lling t~c conncc~ing pin ' i~
slightly elongate~l to allow for the variation in distance between pivot pin 4t and connecting pin 7, an~l between pivvt pin ~ ancl connecting pin 7 as l,hC
rlrst movable member 3 pivols al~out pivot pin 4. The hole 7a thus ac~s as a pivv~al surrace which ~llows sli(ling an~l rolling pivo~l movemcnl.

With this arrangement, movemen~, of t~e secon~l mo~a~lc rllcm~cr (~
relat;ve to the fixed memL)er 2 causes the first mova~)le member 3 ~o pivol al)uu~ ~he pivot pin 4 relalive ~o i;he f;xe~l melnl)er ~. The arr~ngc~ncn~ ol ~lle pivot pins 4, 3j and 7 is such t;hat with clockwise rota.lion of thc scculltl ,i moval~le mem}~er 6 abou~, the ~ivoS pin 5, ~he l;rsl moval~lo mcm~Jcr 3 ;llso turns clockvrise about the first pivo~, pin 4. Furt,heranorc, since the sccontl pivo~, pin 6 is lucated closcr ~o lhc connecting pin 7 l~han is thc l;rst, pivo~ pil~
4, tlle ratiu o~ angular movemenl of` She firsl, mova~)le mcm~cr 3 ~boul tl~(?
fïxesl member 2 to ~he angular movement of ~he second mova~lc men~bcr (;
about ~hc ri~cd membcr 2 is lcss than 1. llcncc a mcchallic~l a(lv~nl.lgc i.s obtained. As a result, compared to a single levcr device, l,he levcr ~rm ~ 9 $llBSTITUTE SHE!~E'r 3~ ~ ~ '; PCTINZ93/00119 l~nglh Or llle seconcl moYal)le Illclnl)~r G m~y l~e shor~er to ob~:~in ~llc S~ C
rorcc at ~he tip of ~he moval)le/~ixe(l mem})ers.

~s shown in figure 1, ~hc tool is aàap~ed f`or use in lensionin~ an~l Sying wirc. 'l`he fixed meml)er 2 is provided with a connector ri~ting 10 which has a yoke(l end portion 11 sized to accommoda~e a urire ~onnecting tlcvicc 1~. The moval)le member 3 is provide~ wi~h a wire gripping device 15 which is fitte~l wit,h spring loa(le(l collets in a similar arrangemenl Lo s~an~lard Pl) rivet grip.

Wh~n using lhc lool, one cll~l lG of ~ wirc is fixe(lly al~ cd lo ~le conncc~or ~evice 1'~, while t.~lC o~her en(l 17 Or the wirc is lhrc~lc(l lhro~
~he connc~or d~vicc 1~, $hcn througll thc gripping (levice 1r). The mo~ l)lc mcmbcr 3 is then moved aw~y from the fixcd mem~er ~ ~y oper~lin~ the second movable mem~er 6, so that the wire is (lrawn ~hrough thc connector deYice 12 ancl thereby tensioned. l~urin~ the tensioning operation, the wire is grippe(l ~y a fitting 1~ which compriscs ~
1~ mechanism similar to that of ~he gripping device 1~, while the movable ~ member 3 is being moved towar~ls thc fixed mem~er 2. Whcn surricicn~teIlsion haæ been obta.ined, the end 17 is withdrawn from the gripping deYice 15 and bent back on the tlevice 12 so a~ to ~;x the wire thcre~o.
~, 'l`he fixetl and mo~able mcmbers 2 an~l 3 Or the tol)l 1 may al50 ~e pr~vidc~l with other suitable fittin~s. l~or examplc, these may comprise ~he jn~Y
elemexlts of a crimping tool, willl one jaw elcInent attachc(l to an CXlCllSil)ll n~ the ~lxed mcm~r :~ which cxtcn(ls out ~o the other side of the moval)lc member 3. With this arrangement, a crimping action mny ~e obtain~
between the mo~able members 3 an(l the jaw element with anti-clockwisc movement of the secon~l mova~lle member ~.

~UBSTITlJT 8HIEEl-WO 94/1~320 2~L:Z~38~3 PC~T/NZ93/~0119 Figur~ 2 shows anotllcr em~)ollimcnt Or tllc present invcnlion use~l t~) provide an amplifisation of movemen~ (negative mechanical advantagc).
~ tool 100 comprises a rlxe(l memùer 20 an(l a first moval)le meml)el 3i).
The first movable mem~er 30 is pivotally connected to the ~ixed mem~er ~2() by means o~ a pivo$ pin 40 rlxedly attache~l to the flxcd men~aber 20. The ~ool 100 is further prnvide~ with ~ linlcage for connecting between the ri~;e(l m~m~er 20 ancl the rirst mov~ble mcml)er 3(). The linkage comprises ~
sccond pivot pin ~0 removably attacllecl ~o the fixe~l member 20, a secon~l movable arm 60 which is pivotal a~out the pivot pin ~0, and a connec~ing pin 70 which provislcs a pivotal connec~ion b~tween th~ seconcl mov;l~)lc member 60 an(l the rirst moval)le member 3(). The second movablc mcmber 60 is provi(lcd ~vith ~n clon~ated aperturc fi()a so thnt i~ m~y pi~ ol about the piVQt pin 5() wililout inter~er~nce ~vitll thc pi~ot pin 4t).
Furthermore a hole 70a in l;he first movable member 60, for accommodating the connecting pin 70 is slightly elongated to allow for thc variation in distance between pivot pin 40, and connecting pin 70, an(l bc~ween pivot pin ~0 and connecting pin 70 as the first movable rnemL~cr 3(~
pi~ots about pivot pin 40. 'l`he hole 70a l..hus acts as a pivotal surr~ce whiclallows sliding and rolling pivotal movement;.

With this arrangement, movement of t,he second movable mem~cr G() relative to the fixed member '~0 causes the first mov~le membe~.3() ~o yivot abou~ the pivot pin 40 relative t o the ~lxed member 20. The arrangemcnt of the pivot pins 40, ~0 and 7() is such that with clockwise rotation of t,hc second movable meml)er G0 a~out the pi~lOt pin ~0, the ~irst mov~l)lc member 30 also turns clockwisc ~out thc first pivot pin 40. Furtllcrlllurc, ~ince ~he secon~l p;vot pin 50 is located further from the c~nnecting pin 7() ~han i~ the rirst pivot pin 40, the r~tio Or angular movcmcnt Or tllc lirst SU~5TITUTE~ $H~El' vvo ~4/~ Z~ 3 ; ~ PCT/NZ93/00119 moval)~e member ;~t~ about ~hc llxed mem~er ~(), to the angular movcr1 it o~` the second movable mcn~l)er 60 abou~ the fixe(l rncmbcr :20 is grcatcr ~han 1. I~ence a negati~!e mechanical adYantage is obt~ined. Various att;lchments may be fitte~l to the first mova~le mcmber 3V and thc f~xc(i member 20, depending on the use which the tool 100 is to be put.

Figure 3 shows a tool generally indicated by arrow 2~ccording to a third embodiment of the present invention. ln this figure, components hnYing the same function as those of figure 1 are identified with the same numerals and description is omitted for brevity. 'l'he linlcage ~or connecting between the fixed member 2 and the first movable member 3 comprises the linkage of figure 1 with an ad(litional linkage for connecting between the movable arm 6 and the fi~ced me~ber 2. The second linlc~c comprises a third movable arm 160 which is pivotal about a pivot pin 1~0, and a connecting pin 170 which pro~ des a pivotal connection between the third movable member 160 and the second moYable member 6. The second mo~rable mcmber 6 is provided with an elonga~ed ~perture 150a so ~hat it may pivot about the pivot pin ~ without interrerence with the pivot pin 15().
I;'urthermore, ;a hole 1qOa provided in the second movable member G, ror accommodatang the. connecting pin 170 is slightly elongated to allow for the ~ariation in distance b~tw~en pivot pin ~ and conne~tin~ pin 170 an(l between pivot pin 150 and connecting pin 170 as the second movablc member 6 pivots about pivoS pin 5. The hole 170a thus acts as a pivotal surÇace which allows slid;ng an~ rolling pivotal movemerlts.

With this arranKement, movement of l,he third movable membcr 160 relative to the fixed member 2 causes the second movable member ~ to pivot about the pivot pin 5 relative to the fixcd mcmber 2 which in turn causes the filrst movable member to pivot ahout the piYot pin 4 relative to thc fiYed rnember. 12 ~;lJB~;TlTUTE~ SHEEl9 wo 94/~X320 ~ æ~3 ~CT/NZ93/00119 This embotliment shows llow lhc linlcage means o~ lhe present inven~ion may l)e increase(l ~o provi~le ~n incrcase in positive or neg~tive mech~nic~l a~lv~n~age.

I believe ~he advantages Or my inv~n~ion ~o l)e as rollows howe~ ~r it shoul(l be appreciated that all such advantages m~y not b~alised Otl all embodiments of the invention, and ~he following list is given by w~y of example only as being indicative of potential advantages of the present invention. Ii urthermore, it is not inten(lc~l ~hat the advanta~es of ~he present invention be restricted to ~hose of the li~t wllich follows: -1. The provision of a link mc~ns ~etwecn ~he mo~ablc meml~er .ln(l lilc~ixed memb~r enable~ t}le mcch~nic~ (lvant~ge of She ~inglc pivo~ io l)e increased, ~r decreased9.depending on whether a higher load is to b~
applied to the movable mem~cr, or whether the mova~le mcm~cr i~
require~ to move through a greater angle l,han the movement of thc link means le~er respectively.

2. The components of the tool may be designed so thal a simple three plate type device is ol)tainell. This minimises the number of componcn~s, making a more compact and lower priced device possible.

3. The design also ~acilitates the ad~lition of com~inations o~ linkages between members moval)le relative to each other, since l,hese may ~)e simply provi(lell in the ~`orm of flat plates stacke~l one beside the other, Witll pi~ connections thorel~etween.

4. The principle Or the inventiorl may be equally applicd to a tlaol whelein the rlrst moval)le ~nember is requircsl to move in an opposiSc scnsc to movement of the s~cond movable mem~)er, by appropriate posilioning of thc secon(l pivot relativc lo tlle rlrsS pivoS an(l linlcage pivol.

SlJE~STITa3TE S5HE~E~T

WO 94/1~320 PCT/NZ93/00119 ,, ; , 2~;~a~3~3 . The tool may be easily provided with a variety of attachments to increase the versa~ility. For e~cample a combination of,~r ri~ret and wire cutting attachments may be provided so that closing of the operating member to~ards the fixed member may result in both a tensioning force on the pop rivet and a compression force on the cutting attachment.

6. The tool may be used for work where amplification of movement is required. For e~3:ample, the tool may be fitted with a mechanism which enables a threaded nut to be rotated several turns for a small movement of the operating handle. In this applic~tion, the tool may have facility ~or varying the location of the pivot points so that a positive mechanic~l advantage may be used to unload a nut. The pivot point loc~tions m~y then be changed to give a negatiYe mechanical advaIltage (ie. a large moveme~t for small movement of the operating handle).

Aspects of the present inveIltion have been described by way of e~;ample only and it should be appreciated that modifications and additions may be mad6e thereto without departing ~rom the spirit or scope thereof.

SllE3STITUTE StlelET

Claims (12)

WHAT I CLAIM IS:

1. A tool comprising a fixed member, a first movable member, said first movable member being pivotally connected to said fixed member by a first pivot means provided between said fixed member and said first movable member, a link mean for linking between said fixed member and said first movable member, said link means comprising at least; a second movable member, said second movable member being pivotally connected to said fixed member by second pivot means, and means for connecting between said first movable members, the arrangement and construction being such that pivotal movement of said second movable member about said second pivot means and said first movable member about said first pivot means is communicated between said first and second movable members by said link means.

2. A tool as claimed in claim 1, wherein said link means comprises at least; a second movable member, said second movable member being pivotally connected to said fixed member by a second pivot means, and means for connecting between said first and second movable members, and a third movable member, said third movable member being pivotally connected to said fixed member by a third pivot means, and means for connecting between said second and third movable members, the arrangement and construction being such that pivotal movement of said third movable member about said third pivot means and said first movable member about said first pivot means is communicated between first and third movable members by said link means.

3. A tool as claimed in claim 1 or claim 2, wherein said link means comprises a mechanical linkage.

4. A tool as claimed in claim 3, wherein said mechanical linkage comprises a single pivot pin and/or pivotal surface.

5. A tool as claimed in any one of claims 1 to 4, wherein said first movable member is provided with an elongated aperture, and said second pivot means comprises a pivot pin which is disposed and said aperture.

6. A tool as claimed in any one of claims 1 to 5, wherein said second movable member is provided with an elongated aperture, and said first pivot means comprises a pivot pin which is disposed in said aperture.

7. A tool as claimed in any one of claims 1 to 6, wherein said first and/or second movable members are provided with apertures to accomodate plastic embodiments which are disposed in said aperture.

8. A method of moving a movable member of a tool relative to a fixed member of the tool as claimed in any of claims 1 to 6, said movable member and fixed member being pivotally connected by a pivot member comprising the steps of:

(i) providing a linkage means between said fixed and movable members, and (ii) moving a movable member of said link means so as to cause said movable member to pivot relative to said fixed member.

9. A method of tensioning or joining wire using a tool as claimed in any one of claims 1 to 6, comprising the steps of :-(i) attaching a portion of the wire to said fixed member, (ii) moving said second movable member relative to said fixed member, so that said first movable member moves relative to said fixed member, the ratio of angular movement of said first movable member relative to the angular movement of said second movable member, being a predetermined ratio less than one.

10. A tool substantially as described herein with reference to the accompanying drawings.

11. A method of moving a movable member of a tool relative to a fixed member, substantially as herein described with reference to the accompanying drawings.

12. A method of tensioning or joining wire substantially as herein described with reference to the accompanying drawings.