Note: Descriptions are shown in the official language in which they were submitted.
FASTENER AND DRIVE SYSTEM
Background of the Invention
11.
Double-ended stud-like fasteners consisting of a machine screw '~
thread on one end, a pancakc-type flange or head in the midclle and a F
special thread tapping screw at the other end are comrnonly used in en- `~
vironments where the primary supporting surface is of a plastlc-type
material with securement therein being a blind application,
'rypical applications of this type are those of autotnotive where
plastic components are provided with boss-like protul~erances having
preformed bores in order to accept the tapping thread end of the stud.
~he studs are usually first driven into the plastic bosses with a stud r
driver leaving the machine screw end to be inserted later through
clearance holes in sheet metal workpieces. Nuts are then used to
clamp the sheet metal against the pancake head of the double-ended
stud which puts all the load on the machine screw end of the stud and
eliminates any added stress to the plastic during installation.
6~
A typical manner o~ driving sucll double-en(led studs has been to
utilize the upwardl~ extending threadecl shank allcl transmit torque to the
fasteners by means of a clluck grasping the threaclecl section. Another
method utilizcs tlle outer periphery Or the flange to drive the fastener.
5 Such applications and tools tend to be signiEicantly greater in diameter
than the diameter of the flange and/or the boss which the stud is to be
associated with. In many such applications, the bosses are in confined
areas and size of the tool is a definite factor in efficiently driving such
fas teners .
In addition to the application or driving problems associated with
prior art systems, a substantial problem exists in securing the fastener
from backing out or rotation tending to remove after the fastener has
been installed. For a variety of reasons, the clamping nuts may have
to be removed and/or the sheet metal removed from the installation.
When torque is applied to the system to remove the nut, it is also ap-
plied to the stud tending to loosen or remove the stud itself from the
plastic. A number of techniques have been suggested to elirninate this
tendency to remove the stud when the nut is removed. Adhesives,
special thread forms, locking means beneath the pancake head or a t
combination of special configurations of boss and pancake head have
been suggested. However, the prior art suggestions are either costly,
cumbersome or contributory to further deterioration and stressing of
the plastic during installation.
This invention also relates to fasteners generally having a head
configuration designed to prevent unauthorized removal. The presence
6~
o.~ any hiyh profile scr~w off~rs the possibility th~t a tight
clamping or wrench.ing can be ob-tained on the periphery of the
head thus leading to unauthoriz~d removal.
The applicant has i.ts co-pendin~ appl.i.cation Serial Mo.
329,543 in which subject matter closely rel~ted to this inventlon
is descrlbed clnd cL~Iimed.
Summary of the I ventiorl
'rhe present invention is concerned w;th a double-ended stud
having dual purpose ribs formed on the upper surface of a pancake-type
flange and a tool for inserting such a stud in an assoc;ated work surEace.
Radially extending, sharp edged, ribs on tlle upper surface of the flange
function to drive the fastener and to embed in the undersurïace of a
secondary work plate clamped over the stud/boss combination securing
the fastener against retrograde movement o-f the stud.
The invention is also concerned with a low profi'le tamperproof
head style incorporating similar ribs on the upper surface of the flange
and a stud centering shank.
A tool particularly designed to insert such a dou'ble~ended
fastener or tamperproof fastener in a workpiece includes an end surface
with a plurality of radially extending abutment surfaces formed the~rein
adapted to engage the ribs on the flange. An axial bore in the too'l re-
ceives the upwardly extending stud shank durirlg lhe driving 50 that the
end surface of the tool may freely contact the flange.
In contrast with prior art methods of applying double~ended studs~
the stud and tool described herein permit the axial driving pressure to
be carefully control'led and confined while the fastener is stabilized Ol'
centered in a properly fixtured driving tool. I'he axial driving pressure
~ , I ,
~L2~06~
is thus controlled and concentrated to maximize the efficient application
of the torque transmitting pressures which are distributed over the sur-
face of the flange rather than applied to the smaller diameter o~ the up-
wardly e~tetlcling shanlc.
'rhe tool is designecl so that its mating end surface is substan-
tially equal to the flange diameter of the stud. 'rhis allows the tool to be
used in confined areas and eliminates any contact of the tool with the
plastic itself.
Ihe ribs formed on the upper surface of the flange should include
at least a primary abutment surface extending perpendlcular to the flange
surface and a secondary surface joining the primary abutment surface at
a sharp apex. A preferred embodiment of the invention shows the secon-
dary surface to be a sloped, camming surface.
It is, therefore, an object of the present invention to provide an
improved double-ended stud with means to prevent removal oE the stud
upon removal of a clamping nut associated thereon.
~ further object of the invention is to provide a fastener with an
improved means for driving into a workpiece.
Yet another object of the invention is to provide a double-ended
stud with a single structural improvement that serves to both irnprove
the driving and locking characteristics of the stud.
Yet another object of the invention is to provide a driving tool
for association with the double-ended stud of the present invention and
with fasteners having tamperproof features.
~1~6~6~
I An~l.(lv~n~:a~e orlllc(1~sign o:f~llel)1c;elllirlv~lltio~lis its.~ y
~o transmitt~lqu~ ~fri~ie;ltly an(~rfc~ctiv~ly ~o~llo~vl)rofilc, tamp~r-
proofhead on perp~n(licul~rtor~ue r~c~iving.surfaces o~r~l~tivel~ low
; height.
In one aspect, the invention comprehends a fasteller
rem~er which includes a first stud shank and a second stud shank
co-axially arranged with an i.ntegral radially extendlng thin
flange intermediate thereof. The Eirst s-tud shank includes a
helical thread formed thereon ancl incorporates means to form a
mating internal thread in a preformed bore in an associated
work surface. The flange defines a lower surface adjacent the
first shank and an upper surface adjacent the second stud shan]c.
An upstanding protuberance means is formed on the upper surface
of the flange with the protuberance means comp.rising radially
extending ribs each having a primary rotary driving surface
extending upwardly perpendicularly from the upper surEace of
the flangc. A secondary surface extends angularly upwardly
from the flange upper surface toward the primary driving surface,
and the secondary surface provides means by which a mating tool
can be cammed gently downward to bring the end of the tool into
engagement with the flange and to bring a drive surface of the
tool into engagement with each primary driving surface of the
fastener member.
The invention further comprehends a tool for driving a
fastener having a radially extending flange in-termediate a thread-
ed shank and co-axially arranged stud-like projections, by
applying rotary torque to protuberance driving means ~n ~he ~lpper
surface of the radially extending flange. The tool comprises
a cylindrical body with an outer diameter substantially e~ual to
the diameter of a flange on an associated double-ended stud.
An axial bore extends from a forward, flange engaging end surface
of t.he tool, and the hore is dimensioned so as to be slightly
greater in diameter and length of the stud protrusion extending
upwardly from the flange on the associated fastener. 'l`he
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-~xtremity of the body opposite the flange enyaging end surface
includes means to transmit torque to the tool, and the flanye en-
gaging end surface includes a plurality of abutment surfaces adapt-
ed to transmit tc)rqu~ to associated protuberances on the flange
of the double-ended stud.
In a still further embodiment, the invention comprehends
a fastener member with a low profile, tamperproof head having a
first and second s-tud shan~c e~tending axially therefrom, said
first stud shank haviny threads with a predetermined thread pitch,
and incorporating means to form a mating internal thread in a pre-
formed bore with the head comprising a radially extending, annular,
thin flange which has a thickness not appreciably greater than said
predetermined thread pitch, thereby forming a flat, lower bearing
surface and an upper, driving surface. The upper surface includes
lS flat surface regions parallel to the lower surface which form a
substantial portion of the upper surEace. Three equally spaced
generally radially extending protuberances are formed on the upper
surface and extend upwardly therefrom, each protuberance including
an abutment sur~ace extending perpendiculaxly upwardly from -the
upper surface intersecting with a camming surface which provides
means to only accept and transmit a rotary force in one direction
of rotation. Each protuberance extends upwardly a short distance
not generally exceeding the thickness of the ~lange, and the second
stud shank cGmprises a centrally located annular cylindrical boss,
with smooth walls, extending upwardly from the upper surface and
has a diameter substantially less than the diameter of ~he flange,
and a height not substantially greater than the thic~ness of the
flange, which provides centering and stabilizing means during the
driving of the fastener. The flat upper surface region, the smooth
surfaced short cylindrical boss and the three equally spaced prot-
uberances, in combination~ create means to accurately and predict-
ably align a mating ~ri~lng tool wlth the head of the fastener, to
insure that sufficisnt torque is applied to the relatively short
abutment surface of the protuberances so that the low profile
- 6 -
of -the head may be maintained, thus insurincl that th~
fastener member will not acc~pt unauthori~ed removal forces.
Other obj~cts an~ advantacJes of the present invention
will become apparent from the follc)winq clescriptlon and the
ac company ln q (1 r~, l ncls .
13rier J)cgcri~ ;on of tl-le l)r.lwir
_________ __
li'igule 1 is a siclc clevaliol1al vie~v Or the doublc-ell(le(l slucl
embodying the featlures Or tlle invclltioll,
]' i~lI`Ci! 2 i ~ pl.lll vic~ O r tl~ , - 2
L0 of l:~`igure l.
Figure 3 is a sidc view, in parl.;al sectioll, of the stu(:l ~nember
inserted in a boss S~II racc thr ougll thc u.C;e Or a part;cularly clesignecl
tool.
I~igure 4 is an elllargcd side view, in ~-artial section, of all as-
sembly using the double-enclcd stud inserl;ccl in a ~vorhl)iec c all(l sllc)willa
a nut rncn)ber c~a~ irlg a seconcl<lry work }~].ate o~e~r tllc flange.
liigure 5 i~s an cnd view oi the tool tal;en from its work colltact;ng~
surface end.
Ii`igul e G is all clc~v~tiollal vic-~, in ~)a1~lial scctic~l-, Or tl~c t~-ol (~1`
the inventiotl in association with a fastener of modiricd clesign.
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Ii'ig-lre 7 i9 a Lol) pl~n v.ie~v of tl~e fa.c;tencl of mocliie(l clesign
s llo~ Ti'io~ c (`~ .
I~eser.l_~ll of the~ t`e.r.~ ed l!`nlb_linlc?nt.s
'.rur~ g first to .l~ig.rs. 1 alncl 2, the d()~lble-elldecl sL~Icl 10 of the
present invelltioll will illelucle a rirst, lower stud shank 12 eo-a~;ially
arranged with a seeontl, upper stucl shank 30 witll arl integralJ paneake-
type flange 18 positiolled interll~ecliatc? the sh;llll;s. ~rhc? first stllcl
section 12 is designecl to be assoeiatecl ~Vitll a blinci bore in a wo:rkpieee
strueture, sueh as a p].ast.ie boss. With this in mind, it .i~s preferably
provided with a threacl eonvolutiotl 1~ Or rather sllarp erested, spaeed
threads. A thread elltting slot 16 i9 formed irl the extrelnity o Lhe ~serew
to faeilitate the anellorirlg~ embedmerlt Or this Iirst shallk ~vithin the bore
of tlle primarSr ~vo~ st:rueturc?. It sllo-lld be llotecl, 1lO\~rL~C?1~, Lll.lt C?~'C?II
. though a thread euttln~ slot is shown in the preIerre(l elnboclimerlt, a
number o alternate eonfigurations ean be used to properl~y form or
generate an internal threacl in the pr.irrlary~work st:rueture.
~ radially extencling flange 1~3 is eonigured to provide a: generally
flat undersurfaee 22, aclJaeent the .first stud SC'C~tlC~ll 12j. and an upper
suraee 20 adjaeent the seeoncl stud seetion 30. 'rhe upper su.rfaee 20
: ~ ineludes a pluarlity o generally radially extendingS protuberan~es ~formed
on an other~vise flat uppc.?r surraee. 'rhese protubeIanees fornl an ilil~
portant ~speet of the inventloll an(3 their dual purpose will be cleseribecl
in detail further herein.
'rhe preferrl?c3 e~llboclirr~ent (~f tlle Inventioll sho~vs thl`e(` I`i~ iC
members extending generally radially of the a:Yis of the fastener. 'rlle
O~L
rlenlb(~I~ Z~ i1l ( o~ ;e ~ t~ O ~Irf;lc t ~(;,
extending sul)sIc~ ially perl)en(licu'Lar lo tlle t'ellla;ll;llg ~urîace regi(~
of the uppel Elange surl'aec? 20. The su~races ~ l'11 also e~;tt n-I radial-
ly oE t'tlt~ cis Or llltl rcl~tt~ller to ,I~ ve I~ ;ilt~ t~f~ y Or tllt.~
rotary t'orc~e applie~l lo the Fastenc~r. l\ secollclary .sutface 2d, in lhe
form of a ram~, extentls upwardly at an acutt? angle to tlle upper ~Iange
surEace and to\varcl llle p1ane of tht~ prilllary d~ c~ ~c~ulrrace 2(`., 'I'lle
eamming surfact? 28 pe~rmits an associated driver, such as 46, to be
plaeed in operative position witb a gradua] and "soft" engagement onto
the flange surfaee 20, rrhe preferred embodin~etlt disclose~s tlle cam- -
ming surface as directly interseeting the abutmeIlt surEace 26; ho\vever,
it should be understootl that intermediate sulraces cou'ld be provided of
any variety Or conEiglIratiolls aIlcl still eollle \~ itllin tlle hl oad s~ope c.r
this invention.
A reference to Figs. 3 and 5 will show a tool for drivmg l!le
above-described fastener and the typica'l applicatioIl for such a fastener~.
A typieal use for double-ended fasteIler6 of the t~yI~e described is Lo
~; aehieve a meaIls to clamp a second~r~i wo1k strllcture or plale-like tk?~
viee to a molded plaslie strueture. Common aF)plieations Eor doub1e-
.
2 0 ended studs include fastener receiving hosses, such as 3~L, formed in
an otherwise thitl plastie structure. 'Ihe bos,ses illClUClt~ a bore 38, oE
a predetermined diameter. In use, the stud member 10 is assoeiated
with a driving tool 46 with the seeond stud section 30 reeeived in a bore
54 in tlle body 4~ of the tool. 'I'lle fasteIlel 111Cn~ C]' In l~ r llC' r(`l~'lill(~
in the tool prior to driving, througll the use o~ magnets or the like (not
: :
shown). Torque transmittiIlg sur~aces, sueh as a ~soclceL 5~, may l)t`
.
9, _
~!~
~26~63~
fornled in lhC~ e,~ C~ .5 Or ~h(' tool O~)l)OSilC` lllt` ~OII; Cn~<l~ g c~;tremil
to transmit lorq~le fl c~nl a po~ver tool to lhe slutl dr iving alt.ac~ cnt ~fi.
It sho-lld l~e noted l;hat t.l~t` di.lllletr.~ o~ lh(` l~ocl~ ~t~, .is s~ si.lnliall~ th.lt
of the flclnge 18 Rn~] ~IppCI~ SIII race 3G of the l~o~ss, 'l`l-lis di~nensic)nal
5 re1at;onship is pcImitltecl by the nove1 conri~uratlon Or thc tool hereir
clescribed ancl bc~co~lles inlportanl in secl~ring r;l~C;lc~llel~: in collrillo(l
regions or in an area ~vht!re the cenlc~r 1ine lo ccnlcr 1ine cli~stance be-
tween adjacent like fasteners is slnall.
As best shown in T~`ig. 5. worli engagil-lg end surface 50 of the
tool 46 is provicled ~vith rl pluralit~T oE grooves 51 equa1 in nu1nber to the
number of ribs 2~.T. on lhe fastener. '~ e;:e grooves ~vi11 easi1y nest ~vitl
the associaled ribs ciue in l)art to the cooperation ol` tlle callllllin~ ralllp
surface 2~ Or each rib tvitli tlle grooves.
:
While the config~lration of tbe grooves 51 may take several forms,
lS all of the~n preferab1y wi11 include a genera11~ perpendicll1arly arrange(l
primary abutment surface 52 adapted for opercll:ivo association willl the
perpenclicularly arl~ange(l primary driving SUI facc 2G c~ tl~ lel-.
'rhe height of the primary abutnlent surface 52 sllollld prc~rerably be at
least as much as the height of mating surrace 2G so that the end surface
~: 20 50 engages top surface 20 c~r tlle f]ange. 'I'he eng.lgemenl ol` tlle r e~main-
;~ der of the surfacc 50 with the top ~lange surface 20 provideR an a1ign-
ment and stabiliæation to the fastenor as it is being driven. ],I'urtller
attention is directcd k- Illc ali~nt ant3 6ta~ iæ;ilion pl`o~idCCl b~ thc
telegcopic a.ssociation Or lllC upl)Cr Stlld Sllatlk 3() witll the boIc 5~ vllic~l
is dimensioncd so lhat botll thc lenglh Or thc stud allcl Illt' dian~elr are
recei~i~ed therein without abut-ment.
- 10 -
.
11;Z601~L
~ l( rcrf~ (`c` to 1~ j~r, ~-1 will .s~lO~v c~ '( ol~ r)or~ nl l'~ ,1ion c~f
thc,~ ribs 2~ on tlle fastcllc~l. ()nce t11e sl:u(,l 10 i.~: prc)perl~ sea~e(1 On the
u})per surface 36 o.t' t11e boss 3~1, the secotldclry plale 40 is po.~,itiol1ed,
preferably throug1l t.he use of a cle.lrcltlce hole, over the stud section
30. '.rhe pl;:lte ~t0 is tlletl C`klll~l)eCl ngainSI: 11Ie ~I~!tl(`l:` ~nt fa( e "~) 0
flange .in a mallnex s1~ n in .IfiC~ . '.l`his clamping~ is acllievecl throug
the use of a nut me~.ml)e:r 44. 'rhe nut mernl)er ~ vill lyp.ieally h.lve tl~e
same hand of rotation fo:r it~s internal threclds as tllat of the thread con-
fxguration'~ 4 on the first stud shank wllieh is driven into thce boss 34.
It should be noted that while tlle pre:ferred embod.irnent sllowsa rnaehine
threacl 32 on the seconc1 ~stu(1 sectiotl 3n, thnt it'is c~ollcei~lble 111.lt t11e
.' stud seetion 30 may be void o.~ 1:hreads ancl that llle nut 1llc,~ml)er 4~ nlay
:: be of a thread forInirlg tyye. In any event, the problems solved by the
invention are the same, that being the seeurenlent o-f the stud 10 from
.
15 retrograde Inovement as the nut 44 is subjectec3 to a. torque to break the
elamping, engagen)ent between the nut a1~ nember ~0. It .s}lot]l(3 be,
noted that UpOIl tigl1t c1alllping of the nut ~ l: ag;li1lsi the p'1.1t.(' 1U,, I.l~c
sharp ape~{ of tlle rib 24 embeds in the unders-ur.raee o'f the plclte in
regions 42, Due to the'perpendicular arrangernent of ~the ~sur~aee 26,
20 torque forces applied to the stud c1urirlg efforts to remove the nilt, axe
resisted due to the locking, embecl1xlent ol the IIb~ 2~ ~rlth t.he plate 40.
. ~ .
While the tool Or the in~enl.;otl has been de~seril)(?(1 in collt1ect.ioll
.
with a doul~le-ended stu(3, reference~to ~igs. 6 a.n(l 7 will point out the '
advantages of such a tool with a fastener of modi.f.ied design. Sever~l
25 important features Or the c]ouble-eildec] stucl eould be ineorpc.)rated in a
fastener having a notl-renloveable tanl~erproor llead. .li`or e~ampie,
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r~ ~ ~ 11 ~
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:
112~6~L
fastener 10a is configurc(l to havc a low profilc hc acl inclucling a pancal;c-
type fLat flange 13a ancl all ax;ally e~;lellcling thrcaded shanl~ ~a. rl'lle
upper surface of the flange will be collEigured with rclclially extcndill~
ribs 24a comprisillg a perpendiculclr dl'`iVill$ surrac~ 2(ia allcl t`altlp ~;ur-
5 ' face 28a perlllittitlg dl`.iVillg ill Ollly OtlC,' direction. ~ CylillCIriC-ll St-ll)
shanlc 30a is axially c~isposed on the fLancsc \vith side walls 32cL extending
a height not substarltially e~;ceecling the height of clriving surface 26a.
~s in the double-ended stud enlboclinlent, the flat surface region 20a is
a substantial portion of the total upper surface area of flange 18a.
The dri~ing tool 4Gcl can be asso(~iated ~ith tlle talllpei pl~ooE
fastener 10a in a manner identica'L to lllat desccribe(l above re'lal;ive to
double-ended fastener 10. 'I'he tool 46a is described witll like refer~
ence nunLerals identifying like eleme~nts to 46 with the,acldit;on of the
, suffix "a". It should be particularly noted that bore 54a is of such a
diameter as to receive stub shank 30a and supporl the side walls 32a
therein to center anc~ stahili~.e'the fasteller 10a clurillg dL iVill~ 'lle
.
~ ~ stub shanls 30a will be a height great enough to accomplisll this coopera-
.
tion with the tool 46a but not so great as to permit the fastener to be ~
removed through the grasping of the shallk with a tool. ~rrhe cooperative
, ~
interrelation betwec~lL flat surfaces 50a of the too'l and thr-` fl'at upper
:: : :
surfaces 20a of the fastener and the inner periyhery of bore' 54a of the
tool and short side wc-Llls 32a Or thc,~ boss Or tllc~fastel-ler c~cllef~ anc3
critically stabilizes and centers the tool Oll the fastener and prevents
the tool from cocking out of the a~i~s Or lhe faslcller.
~ 1 2
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] Thus, l!~cre ;s sl~o~vn a1lcl de.scl~ibe(l 1 d0~ etltJe(l Sl,lld ~vhicll
includes novcl clri~1in~,~ sllrfaces wllich alst> runctiotl as 1 nleans to locl;
the fastener from re]lloval as tlle nut n~cmbcr is k~oscn((l thcterrc)m.
driving of a f~lC teller inlo a worlc sUI rat~
While parlic~lllr elllbotlilllerlts oL tht~ pre~ent invetll;on have bt-~en
sho~vn and describe(l/ it ~,vill be obvious to tho.se skil1ed ;n the art that
changes and mod;ficat;ons maybe made w;thout departing from Lhis in-
vention in its broader aspects and~ thelefore, the lilll in the appencled
claims is to cover all such challges and nlodifications as iall within the
true spirit and broacl scope of the invenlit n.
:
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