CA2080798A1 - Plastic injector - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A device for realigning or rebushing ball joints.
device utilizing air under pressure to drive a rod forward to remove plastic material from a cartridge and inject same into a ball joint being realigned. The rod is operated by movement of a piston, and air pressure is utilized to return the piston or retract same after use. The device also provides a self-cleaning and self-aligning feature and an air pressure relief valve.

Description

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rrhe invC~ntion relat-es to appdratlls p-~rti~lllarly adapted - for realign~ng hclll joints, journal bearings and the like, ~hat have be(ome worn thr(1l~gh llse, WLthCJllt reqUirlng disassembly c,f the j-,ir,ts or re~oval from the vehicle.
It lS known tnat ~)earings can be formefl by pourinc3 or injec-ting bearing material in liq-lid forrn into a space between a shaft and a hearing housing. For this purpose, a low-melting metals E~G. Rabbit Met.a]s, plastlc, or synthetic resin compo~nds have been used. These have been described ~' ln in the prior art as shown, for example, in U.S. Patent Nos.
2970869 and 3091486.
U.S. Patent NO. 3650004 discloses a process for in situ repair of worn ball joints which requires the positioning of the bearing part so as to place the ball and shaft, and the 15 retainer in an operative position, injecting into the space between those parts, plastic hardenable composition and continuing injection until any grease or loose bearing fragments have been displaced from between the bearing parts. The composition is then allowed to harden to form a 20 surface against which the ball or shaft portion of the bearing wears. ;
U.S. Patent No. 3551640 discloses apparatus adapted to ~' utilize a process similar to that discussed above. This patent provides a gun-like device and an especially prepared f 25 cartridge of tempered plastic for realigning or rebushing a ' ', ' - 1 - ' ':

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bal l j~ r~t ~r 1-l t ] e ro~ nd, or ot~ er jc~i.rlt th~t ~k)e~ not h~l~re hc~ eaLlrlgy. The matu-~r~ l injecte~l with thi,s clevice, ~5 hsrcl en')ll!lJ~ 1 !) r(-`m!)'~7e the looseness and h'f:`ar of a join,~i.
The clevlc f~ util1zes ai ~- p:L-~sure which clri~es cl pi~iton anl piston r~j~ f~rwarcl, th~ rod cornlng into contact, with -the c,artridge t,o ~Jush the mate~ial from the cartricl~Je into -the joint, to be realic3necl. The plastic ma-terial 1n the car-tridge is heated to liquid form prior to the injection step.
'i, 10 It is thereEore an object oE the presen-t inventivn to provide a ball joint rebuilding which i,n principle utilizes structure similar to that disclosed in prior art patent no.
3551640 ~ut one that is much improved thereover not only in efficiency, but ease of use.
,~ 15 Accordingly, the invention relates to a ball joint rebuilder a~sembly of the type inclucling a hollow cylinder having a piston freely slidable therein. The cylinder comprising a cylindriaal side wall having a first end cap mounted on one end thereof and a second end cap mounted to the other end -thereof. The first end cap having a central opening therethrough, the first end cap also having an outwardly extending threaded end with the central opening extending therethrough. A piston rod i~ provided having one end secured to the piston, the opposite end oE the rod being ~slidabiy engaged through a central opening in the second end :, , . : : ~

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,- eap~ Tuhe m~-~lllS (~;re pro~7~clecl, at:tach~d t:o t,he second end ,. cap, ~o ~xt(:rl~3 ou~-wa.rd:ly therefrom, the }:)ore of the tuhe means Ijeln~J ~t~ dli-Jned wlth tll~ centra] opel-li,n~ i,n the ::
. second c~r~ . A heat:Ln~l co,il is posi.tionecl arounf,l ~,he ,' 5 outer circurllference of th!? ~ be means and ~ cartrld~,.Je, .. . .
.~containing piastics mclterial is removably inserted within ~,!the bore of the tube means. Restrietecl orifl C'f` means are provided at the end of the tube means remote :Erom the seconcl ~,end cap means throllc3h which plastic may be (,iispense-l when ,~.10 the cartriclcJe is subjected to heat :Erom the heating roil.
he as.sembly further i,ncludes means to supp],y air under pressure through the secônd end cap means to act against the ,,lpis-ton to retract the pis-ton within -t,he cylinder, and additional valve means are provided in the second end cap ,~15 means, the valve means being manually operated to be "open"
when the piston is moving towards the second end cap, and .~maintain closed when the piston movement i.s reversed.
The invention will now be described by way of example only, reference being had to the accompanying drawings in which.
Figure l is a side view of a prior art device shown in elevati.on and part section, Figure 2 is a side view of -the device according to the jpresent invention, in exploded form, and part section; and 25Figure 3 is a side view of the piston according to the present invention.

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FicJule ] shc-ws a p~l-)r c-lrt devie as disclosld in Paterlt No. ,551640, ar~ the ollowirlc3 descriE)-tion is provil1ed. ikc-ording t~:, this ~articulclr pr~or art device, a ball joint ~ebuilder 10 is provided with a hlJllow cylinder ; 5 11 which -th~eadedly receives a cap 12 at one end. Cap 12 is provided with an internally threaded neck 13, whi~h will receive the e~-ternal threads 14 of cartrid~3e 15. Cartrid~3e j~ 15 carries on its interior a specially prepared te~perecl plastic 16 which is to be forced into a joint Inot shown).
The opposite end of the cartridc~e 15 is provided with external thread 17 which receives the adaptor 18, which is `, used for fitting different alemite openings in the joint to j be realigned.
A heating coil 19 is used to encompass the cartriclge 15 in order to heat i-ts contents and heating coil 19 is plugged into plug 20 of extension cord 21 which will be plugged into ¦ an electric outlet or the like.
A push rod 22 within cylinder 11 is attached to a piston 23 and provides a means of forcing the plastic 16 1 20 after it is heated, into the joint to be serviced. A cap 24 is threaded onto the other end of cylinder 11 and is provided with an externally threaded neck 25 which receives the air control valve 26. Air control valve 26 is secured to the air line 27.
In use, the adaptor 18 connects the cartridge 15 to a 208~7~

ball. jolrlt ~ t~.e rod erld ~ re~ov~ncJ t]-~e aler~l.te gre;lse fi.tt1r~ arld i.rlsert-l.r-lg either the arlclptor 1~ or ~he cartri(:lge i~to t~ n~nc^). ~ heatlrlg ~ l is sl:iEJp-d ove~ the cartridcJe 15 wnich is screwe(:l 1nto the necls 13 f~f cap 12 of I lO. Thi~ heat.ln.g coil :~9 is allowed to heat for a specif LC tlmf-~ ancl then the ai~ under ~ress~ e :is releasecl by opelling the 3:ir control vllve 26. Whe~l-th~.s oc.cu~s -the ; compressed a.i.i- forces piston 23 towards -the opposite end of . cyl:inder 1:J and in doing so carries the attached push rod 22 forwarrl which enters cclrtridge 15 and forces the ~ specially preparecl p]~stic ]6 int.o the ba~l joint or tie rod "'f end whereilpon the joint is realigned. :
t is noted in this piece of prior art that cartridge ~ 15 may be refilled or replaced. .
$ 15 It i.s further noted that after injecting the tempered i plastic 16 into the joint the join-t is ready for use and l the empty car-tridge is then removed and a refilled cartridge .~ 15 is inserted into gun 10. .:
.~ The greatly improved design according to the subject ~.
invention can be seen in Figures 2 and 3. since the device of Figure 2 has parts corresponding to the prior art (Figure 1) similar numerals have been used where possible.
Referring to Figure 2 which is shown in exploded format the device includes a hollow cylinder or sleeve 11 . 25 and two end caps or fittings 12 and 24 respec-tively. While ..
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tl-~e i,:n-~ c.ll~s ~Jrld ~ n(lers could be threadably inter-onn(,~ in t~le embodinli~nt shown, encl a~s 12 and 24 are ed(-ll p~^ovl(lf-d with ClrC ulal- recess seat,s 2~, the diamete~ ,f e<-l~h ~e~t belrlcJ ~hai, of the hollow tyllncler 11.
Th~ee COIIp~ tC, are intelcc)nnected clncl a,re ileld together in sealed rel,3tiorlshiE:) hy bolts ~not shown) which exteni,l from encl cap 1~ to ~nd ~ap 24.
~'!The ,levice 10 ciiffers c-nly sliclhtly in structure from 'the previ~usly clescribec3 prior art device, at ~ts forernost end. The de~ice according to the subject invention includes a tubular extensi,on 29 locatable with end cap 12 to extend ~,outwardly therefrom. Cartriclge 15 is loca-ted within that ','extension 2~ and heating co1ls l9 are wrapped around the end 30. Thread 17 are provirled as before, to accept the aforementioned adaptor 18. Likewise, threads 25 on end cap 24 are secured to an air line which in this embodiment is ¦ not shown.
~There are three important and distinct improvements as ibetween the device according to Figure 2 and the prior art, as shown in Figure 1.
The first is that the free floating piston 23 includes a rubber sealing ring 31 and two plastic bushings 32. The latter being in contact with the inner surface of cylinder 11 so as to effectively clean that surface on a continual basis when the piston moves back and forth. The self-cleaning bushings and seal also provide a self-aligning : . 2~g~7~
f(atllrt n~)t f~ TId lr~ the ~-~ri~r ~m^t c1ev:Lce.
The s~-~concl im~orlarl~ im~rovement is the use of aiK
~rescure t~ rcli~ t t:}lf=` ~)ist-~n wi~ ir-, t:he eylirl-ler. AS C1CIn ~e seen ~r(~~lll FL~JIIre '', an air -Lnlet is prov~-led through end cap 12 at 3~:. Wht~ iston .'3 has travelled its full extent and ~burs acJainst seat 2~, air is introduceri throucJh va]ve 34. The r-,--e~sllle ~Jeneratecl acts sclalnst the rear surface 35 of piston 23 and for-es -the E-1ston haclk into an operative position, followirly which, a new cartrid-3e 15 May he inserted, to be u~ilized in the nex-t application of gun 10.
n the preferred embodiment i-t is :irnportant that the ;, .
~`~ cyllnder l1 is steel~ Most prior art devices were constructed of aluminum, which proved susceptible -to damage during continuous operation.
j~ 15 The thlrd feature not shown by the prior is the -~-i provision of valve 36 within end cap 12. Valve stem 37 extends through end cap 12 via bore 33 and is adapt~d to g slide freely within bore 38.
When the device is in use, in the operable position with piston 23 ad~acent end cap 24, the valve 36 is "open"
ie: unseated. As piston 23 is moved by air pressure against its front face 39, the inside face 35 of piston 23 acts against valve 36 and pushes valve stem 37 through bore 38.
;~ During this movement of piston 23, air is expel~ed through '~ 25 bore 38 to ~tmosphere. At the full extent of piston travel : :

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~alve 36 sf~-3tS 7nt(-, conlc,-~l depresslc)n 40r thlls sealirlc~ off bol-e 3~,. Dllriri~J the reverse (-)r retraction o:f piston 23 wit;hln th~ lincler 11, valvf~ ~6 remai.ns closed thus permittincl f~lll prfssule to be applled agc!lnst face 35 of ~ 5 p:ist:on 23. hlr wlthin the sp.~!ce hel~lil~l-3. piston 23 cluriny ;.3, this phase of operation is expelled throucJh 25 arld the air `i control vaive (not shown) in Figure 2.
he opexat:iorl of vaIve 36 is, of course, manual in this i preferred emboc]iment, but collld c)f course be sprincJ
actuated.
~ The scope of the present invention will now be defined `~ by the appended claims.

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Claims (2)

1. A ball joint rebuilder assembly of the type including a hollow cylinder having a piston freely slidable thereon, said cylinder comprising a cylindrical side wall having a first end cap mounted on one end thereof and a second end cap mounted to the other end thereof, said first end cap having a central opening therethrough and further provided with an outwardly extending threaded end, with the central opening extending therethrough; a piston rod having one end secured to said piston, the opposite end of said piston rod being slidably engaged through a central opening in said second end cap; tube means attached to said second end cap to extend outwardly therefrom, the bore of said tube means being axially aligned with said central opening in said second end cap means; heating coil means positioned around the outer circumferential end of said tube means; a cartridge, containing plastics material removably inserted within the bore of said tube means; restricted orifice means at the end of said tube means remote from said tube second end cap means, through which plastic may be dispensed when said cartridge is subjected to heat from said heating coil; said assembly further including means to supply air under pressure through said second end cap means to act against said piston, to retract said piston within said cylinder; and valve means in said second end cap means, said valve means being operable to be in the "open" position when said piston is moving towards said second end cap, and maintain closed when said piston movement is reversed.

2. The assembly according to claim 1 wherein said piston includes a circumferential rubber seal and plastic self-aligning bushing.