Note: Descriptions are shown in the official language in which they were submitted.
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Bl~CKGROUND OF THE I~ENTION:
The pre~el~t invention relate3 to expansion anchors
and, ~ore p~rt~cularly, to such anchoxs wherein an 2xpan~ion
~leeve ~L8 e~xpanded radially by dra~i2lg a taper~d expander
5 eles~ t lnto the leading ~nd of ~e sïeeve and by ~an~ o~
an actuating element which extend~ outward:Ly of the bore hole.
Exp~sion anchors of the head-out t~ype are well known
a~d have ba~n widely u~ed in ~3e artO These anchor~ have
th~ ad~antage that the anchs:~r ~txucture does not permaneI~tly
10 pxojec~ above the floor or wall surace a~ a stud anchor
does, or example. That i8, s~pon removal o the boït in
such a he~d-out anchor, a f lush hole remai~s in the masonry
~ux~ace. Thi3 i~ particularly important where heavy equip-
m~n1:, which i~ other~i~e too heavy to lift over a projecting
15 ~a~tener~ i~ installed in 3uch a mannex ~ it must be
remov~d or relocated.
One ~uch l~own head-out anchor includes a pre-a~sembl~d
lock nu ver the sh~ of the bolt which is embedd~d irlto
the side walls of the predri~lled bore by turnillg t:he head of
- 20 the bolt through a limlted nu~ber of t:U~15. ~hi~ des~ice
~uf ~or~ with the disadvantage that there i n~ po~itive load
re~ction between the expa~sion anchor and t:he ~ide walls of
~he bo~e a3 lthe tapered expansiLon cone i8 ~ituated abn~re ~he
expan~ion sleeve . That ~ s ~ in order to provide a positi~e
25 load raac~ion agai~l~t the wall~ of ~he bore hole, the
taperl3d expansion cone mu~t be dispo~ed below the expansion
sleeve in ord~r to p~ovide the positive load ~eaction.
~urther, ~uch expan~i~n anchor~ are not readily re-tightened
a~ter yielding to the high ~tre~ load~ as occa~ioned by
30 prolonged use.
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Others types of expansion anchors are known wherein an expansion
anchor sleeve is expanded radially by drawing an expander element into the
sleeve from one end by way of an actuating member which extends into the sleeve
from the other end. These devices, however~ suffer with various disadvantages
such as complexity and expense occasioned, for example, by the need for a
screw-machine operation for the manufacturing of each of the individual parts.
Theseldevices further suffer from the disadvantage that under the stress of
high tension or pull-out loads, the expander element can be pulled all the
way through the sleere which, accordingly, results in a failure of the expan-
sion anchor. While attempts have been made to solve these problems, as byutilizing additional piece parts such as rings disposed at the end of the
expander member which is remo*e from the sleeve, such cures function to fur-
ther complicate the construction of the device and to add to its manufacturing
cost.
Another known expansion anchor of the last-mentiQned type util-
izes polymer rings disposed between the trailing end of the expansion sleeve
and the shoulder of the bolt. The ring is compressed or even crumbled if it
is necessary for the bolt to be drawn downwardly during the expansion process
such as when an undesired space is initially included between the concrete
ZO surface and the object being bolted to the concrete.
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~L0S~923
SU~IARY OF THE INVENTION-
According to the present invention there is provided an expan-
sion anchor for use in a bore hold formed in a g:iven structure comprising:
an actuating element having a shank of a given diameter and a threaded lead-
ing end of a reduced diameter; and expansion sleeve surrounding said threaded ~ :
. portion, the diameter of which substantially corresponds to said given dia- :~
; meter and the trailing end of which initially engages the walls of said bore;
a tapered element threadedly engaging the leading end of said threaded por- : ~.
tion; wherein the leading end of said expansion sleeve is expanded radially
and into wedging engagement against the walls of said bore by drawing said
tapered expander element into the leading end of said sleeve; and~ wherein
said actuating elernent includes an integral tapered transition portion be- .
tween said shank and said threaded portion which initially engages said
trailing end of said sleeve against said walls in fixed relationship there- : :;
with prior to the radial expansion of said :leading end of said sleeve and
~ whose taper with respect to the axis of said actuating element is substantial~
-. ly greater than the taper of said tapered element for radially expanding said
~ trailing end of said sleeve into deeper engage~nent with said walls while
: drawing said actuating~ element into said sleeve after said leading end of
said sleeve is radially expande.d into fixed engagement with said walls.
In a preferred embodiment, the integral transition pbrtion is .;~
- conically tapered. ``
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BRIEF DESCRIPTION OF THF D~WING:
The advantages of this :invention will become more readily appre-
ciated as the same becomes better understood by reference to the following de-
tailed description when tc~ken in conjunction with the accompanying drawing
wherein:
Figure la is a preferred expansion actuating means, i~ the form
of a head-out bolt, in accordance with the present invention,
: ~igure lb and lc respectively illustrate an expansion sleeve and
a preferred expansion cone suitable for use with the actuating means of
Figure la;
Figure 2 is a perspective view of the expansion sleeve of Figure
lb, in accordance with the present invention, after having been formed from a
slot sheet metal material;
Figures 3a and 3b are perspective views respectively of a prefer-
red expansion cone, and an alternate embodiment of an expansion cone;
Figure 4 is an enlarged cross-sectional view of the expansion
cones of Figures 3a and 3b illustrating somewhat more clearly the double
tapered angular configuration thereof, in accordance with a feature of the
.~ present invention;
~ 20 Figure 5 is a ~iew taken along the line S-5 of Figure lb;
Figure 6 is an assembled view, in partial cross-section,
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of an exp~3:i on ancho;r, ln accor~laY~ca with the principles
of th~ present in~ention, sho~n 1~ cor~ ction with an
axlally over~ized ma~onry bor~3 h~le; and,
~gure 7 illuatrat~ a vie~q similar to Flyure 6 and
S further lllu~rat~a a ~truc: tural fPatur~ whexein the
actuatirl~ me~5 iS draw~l downwar~ly in o th~ bora hole to
comp~n~atc for unde~ir2d lnitial spri~g b~ 3;wearl the
aetuati~3g ~a~s a~ad the laaterial ~ ace.
DETAILED DESCRIPTIOP~o
.... .. . . .
Referring now to Figura la~ there is snown a pr~erre
exparlsion ac~uating ~all 10 which ~ake3 th~ form of a
head-ou~ bolt ha~ing ~ threaded leading end 12 and a ~hank
14 at its tralling erld. Th~ trailing end i3 outwardly
terminated in ~n i3ltegral torque-tool erlgaging mean~ 16 in
15 t~e ~o~ o a bolt head and haviny an inte~ral wa~her 18
provlded therewith. Expan~ion act:u~ting m~arls 10 preferably
- compri~es a high-grade ma~erial such a~ Ç;rade 5 alloy ~teel.
Further, the threaded end of mean~l 10 is provided with fine
thread~ for maximum effective drawing force applied to the
20 axpander cone as well a~ maxi~um t:en~ile s~reng~h as will be
di~cus~ed more fully hereinafter. That i8,, t:he thread is
selected to ~ini~i~e the dep~;h of the roots ar~d to be
whate~Jer ~aximum nomi~al ~ize t~at will freely pa~s thru
axpaJasios~ ~leeve o~ appropriate thickness, thus providirlg
25 ~aximum root diaDIet:er and ~kiv~a dia~eter d~erlsio~ for
maxi~um ten~ioAal strength.
Figur~s lb and ïc ~e~pec ~ vely illust~a~e an expansion
sleeve ~0 a~d ~n ~!3xpal~der ele~ent or cone 30 suitable for
u~e with ac~uating mean~ 10 of FiglLre la, as w~ll be
30 described m~re fully h~reinat~3r.
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A conlc~î tran~:1 tiorl portioll 11, of a~ le C, 1
provided betwl3en the l~ading threaded portios and the
trailing portic;~n of the actu~ing means or bolt 10 to allow
l:olt 10 ~o draw it~elE downwaLrd by radially ~xpanding th~
5 t~aillIlg e~nd of sleeve 20. Thi3 corlical portion 11 i~ o~
sufficiently wide lllcluded angle~ such tha~ tha sleeve 20
will m:>t b~3 prematurely ~xp~ded as the an~hor a~sembly is
pushad into the bo~e hol~. Thi~ provi~ or allowir~g the
bol~ to dr2w i~elf dow~w~r~ p~r~lcu~l~ u~aful in tho~e
10 3ituations wher~ there i~ a space be~ween the c:oncrete
~urface aIld the ob~ct 3~eing fa~ened and wherQin ~hi9 gpace
re~uire~ tantial bolt tension to draw..the object fi~ly
agaln~t the concrete. The radia} expan~io~ o~ ~e trailing
e~d of the ~leeve is ne~::e~ ry becau~e the threaded cone 30
at the 1~3ading end will have previ.ously locked the 31eeve
again~t ~e wall of the bore hole.
RQferring ns:~w to ~igure 2 ~ there i~ 3hown a persp~ctive
view of *xpan~ion ~lQe~3 20 in acc:ordall~e ~ith the present
inventioll. Expan3ion ~ eave 20 i~ pref~ra~ly in~tially
pro~id~d ~ the ~fla~N~ thalt i~, a8 ~ blar~lc oiE rela~ive ~hick
~he~t mat~l material. The ~lat or bl~ re~erably
~nit~ally provided with aligned longitudinal ~lots 22 and 24
which rsspecti~ely extend from oppo~i1te eT~ds of the blank
and lor~gltudinally eacte~ld a gi~n di~tance into the ~leev~
~5 whlle leaYil~g an intermediate suppt)rt w~b thereb0tween. The
blaIak is rolled ~uch that it~ c:on~Erontillg end~ pro~ride
another longitudinal ~lot 26 extending from e~d to end of
the no~d cylindrically ~hap~d ea~pansion sleeve. The uppsr
cornex~ o~ ~lot~ 22 ~nd 26 are preferably deflected or
~lared outwardly ~ at 28 ~o as to provid~ ~harp yat ~:
deflec~able tin~-like bite edges for engagemen~ wit~ the
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8 - N.G. Scheuer ~
side wall 3tructure or material of the bore hole as will be
described more fully hereinafter. Thi~ feature is further
illustrated in Figure 5. Further, during the manufacturing
operation, the direction of sheer of the blank of sleeve 20
can be selected such that the sharp edge of the stock is
disposed along the exterior diameter of sl~e~e 20. The
outside diameter of sleeve 20 is selected to approximate ~:
or correspond to the outside diameter of shank 14 of
actuating means lO in Figure l. However, as described more ~ :
fully hereinafter, in currently preferred practice, the ~;
diameter of sleeve 20 is deliberately oversized.
R~ferring now to Figure 3a, there is shown a per~pective :~
view of an expander element or expander cone 30 in accora- :
- ance with a preferred embodimen1: of the pre~ent invention. ~
lS It can be seen that cone 30 is provided as a screw-machine : ~:
part having a central thxeaded bore with threads corres~
i ponding to the fine threads provided at the leading end 12 -
of actuator mean~ lO of Figure l. Cone 30 is provided with ..
a first tapered portion 32 which extends from the trailing ; -~
:: 20 end o~ cone 30 toward the leading end thereof. At an
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intermediate point along the longitudinal surface of cone :~
30, a transition occurs whexein the angle of the taper is
increased to provide a second tapered portion 34 the func- -;
tion of which will be described more fully hereinafter. i~
Finally, cone 30 i9 provided with a pair of diametrically
~ opposed tabs 36 and 38 which are ~ent from the edge portion
: of the trailing end of cone 3 0 .
Referring now to Figure 3b, there is shown an alterna- : . :
tive embodiment of an expander cone 30' in accordance with
the present invention. Cone 30' differs from cone 30 of
Figure 3a in that a knurled portis:)n along a circumferential `:
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band at the trailing end of cone 30' is providedO The
knurled portion 39 provides essentially the same function as
tabs 36 and 38 of Figure 3a~ by gripping the inside diameter
of the expansion sleeve so that the cone does not turn while
being drawn upward by the bolt~
Referring now 1:o Figure 6I there is shown an assembled
view of partial cross-section of an expansion anchor A in
accordance with the present invention. It can be seen ~hat ~ ;
the axial depth of the bore B in the masonry M exceed~ that
of the o~erall length of the expansion anchor A. This is
of no consequence a~ the expansion anchor A in accordance
with the present invention grips itself within the bore by
means of radial expan~ion against the bore walls irrespec-
c tive of the depth of the bore. That is, it need not bottom
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.: in the ~ore. Further, the anchor can also be readily used
l~ with through holes or bores. Il: can be seen that once anchor
A i~ nnserted into the pre-drilled ~ore! the deflected co~-
~; ners 28 of s~eeve 20 bitingly engage the surrQunding mater- ...
v ial of the bore wall ~o as to prevent subsequent rotation of
~leeve 20 as torque is applied to b~lt head 16. However, :~
these tabs are designed so as to readily de~lect inwardly ;~
~ the anchor assembly i5 installed through a comparatively :
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.: tight hole in a metal object or machine base or if the
sleeve must pas~ by a hard particle in the concrete, Fur .
~her, as the torquing operation continues, cone 30 is drawn
: 25 upwaraly into sleeve 20 thereby causing radial expansion of
: sleeve 20 ayainst the surrounding material of the bore until
: the sleeve is snuggly wedged against the walls of the bore : -
B. Thereafter, anchor bolt l0 can be threaded away and
removed from bore B while ~leeve 20 remains firmly fastened
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within ~che bore B and wedgin~ly bngage~ with ¢one 30.
Figure 7 i llu~trateEs the ~unctiorl of the previou~ly
de~c~i~ed cc3nical ~can~ltion por ic3rl 11 ox' a~chor bolt 10
wherein the trail ing Rnd of sleQve 20 has b~erl expanded by
5 the corlical transition po~ on to allow a final downward
mo~ nt or greater pene~ra~ion of anchor bolt 10 to close
up any unde5ired ~pace.
Figure 4 lllu~trates somewhat more cle~rly the diDu3n-
~ional rela~io~hip of ~he multiple-function s~ruCt~re of
10 exparl~er cone 30. It can be ~een that tapexed 3urface 32
i~ provided wi~h a given initial ~hallow ~apex defining an
angle $~ ; arld that the 3econd tapered ~ur~aGe 34 i8
p~ovided wilth a steep~3r taper at ~he bo~tom or leading end
o~ the cone whlch is designated a~ ~ in F.igure ~. This
double t~per ~eature, in accordance with th~ present
inven~ion, ~ignificantly increa~es the applicability and,
thare~ore, ~he u~ility of ~he expa~l ion anahor~ That is,
the shallow ~aper c~e of ~apered por~io~ 3~ normally fully
e~pand~ the ~leeve i~ high-~tr~ngt~l concrete ~ith app~opriate
20 torquo ~r~ on the anchor bolt 10. However, in low-
stxe~gth concrete, the ~teep~r taper ~ i8 drawn i~to ~he
sleeve a~ an again appropriate torgue i~ appli~d to the
anchor bolt 10. Thi~ allow~ ~or ~he de3ir~d le~el of
~ ~a~tening torque ev~n wi~h a wide variatio~ the strengths
'' 25 0~ 8ub8txate materials.
It will be appreciated by those ~killed in ~he art~
that in ~he~e lo~-strength s~bs~ra~e materi~l situations,
: . a shallow taper alone could be dra~n completely through the
sleeve, ~ven at rela~ively low tor~ue level. ~n this regard,
the ~teeper taper at the bottom of the cone is intended to
o~er grea~er resi~tance ~o ~ension or pull~out loads which
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might othaIwi~;~ draLw ~ ~hallow taper t.hrough tha ~leev~
In any event, m~xim~l allowa~le bolt tor~u~ nor~ally
attained ~t the point wher~ the steep~:r taper ~ enter3
~he ~leeve 20., Howe-rer, the steeper taLpar provides the
addPd ~eature ~at th~ ~xpan~io2l anchor in accordance with
the pr~ent in~rerltion can with~tand greater pull-out or
tensile forces with las~ ~lip or cr~ep tha~ i~3 possible with
~hallow taper alongO Fu:i:ther, any slip or creep resulting
~rom ten~ile loads or bolt ten~ion can be ~eadily comp~n~ated
Eor by merely re-tightening t~he bolt.
~ Althougll it is ~omewhat difficult to depict in the
~ ~ previou~ly described Figures~ it should~ be appr~ciated that~
in accordanc:e with a further feature of the pre~en-t invention~
expandc3r c~ane 30 and expan~.ion ~le,eve 20 are dleliberataly
over~ized., For exampla, the exparlsion a~chors l~tanded for
:; the normal 0.25, 0~50 and 1.00 inc:h boxe hole application~,
.
are prefer~bly greater than t:hese normal diameters~ for
example, by a value oi~ appro;7cimate~1y 0 ~ 010 inche~ . In
c:urrently pr~3ferred prac:tice, ~Eor e;xample, the " 0 . 5 " inch
.~ 20 anchors are provided with OoS10 irlch dia~ter members. Thi~
oversized structural :Eeature is utilized cn ~oth the expa~ler
colle 30 (see dimen~ion D in Figure 4) and expansion F3leeve
20 in ~t~ diametric dimen~ion. Thus, by :Eorcir~g an over~
b
8ized ~leeve of maximum poqsible material thickness over
an over~3ized cone, the maximum pos~ible expanded diame ter
i~ realized in both low ar~d medium s~renq~L concrete. The~e
ov~rsized di~n~ion~ are ne~er1:hele~8 accomodated by the
re8pective bor2 holE3~ as m~onry drill~ ~ for example,
typically measure 0.,015 ts 0.025 inches greater than ~heir
30 "noIIllnal" diamatex~Bo Fur~her, in actual practice, these
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drill blt~ drill hol~ e~.7erl larger tharl their over~.i2~d
dimerlsion~ .
Thf~ over~ize dime.n~ion3 typ.ically proYided in masonry
drill bits 1~ n ce~axy to accomodate wear O:e theix
- S car~ide t~p~ and because the bits oten dc not dxill straight
hol0~, Thu~ an over~ize hole i5 needed to ~2nRure that
typic:al one piece a~chor shell~ or shaft~ ~ill fit; into
the hole.
Thus, ~tated somewlhat dif ferently, l:hi~ fsatllxe, in
ac:cordanc~ with the pre~ent invQntion ~ ~ills a s~tantial
portio~ of the heretofore unu~ed ~pace i~ t~e bore hole
prior to exp~ion o~ the sleeve --i,e., even be~ore the
~leeve is expanded-- in order to achieve the greatest
pos~ible 3ub~equent expansionO In~ currently pre~erred
lS practice, the over~ized dimension~ of the e~pansion sleeve
20 and ~xpander cone 30 ~e ~omewhat les~ than the typical
m~ximum ovar~ized dim~n~ion of th~e typical masonry drills.
Thus t gOIIIe 0~ the previollsly unu~ed ~pace ls left unu~ed.
How2~er9 it ~hould be appreciated that this is done
because ma~onry drill~, fox example, typically do not drill
per~ectly stra$~ht hole~ and, accordingly, ~uficien~ clear-
ance mu~t be provided arld aïlowed to ensur~ that ~he l:olt
anchox as~embly *rill fit the hol~.
It should IlO~Q be appreciated that ~e thr~e piece
2~ expansion a~qe~ibly, in accorda~ce with the pre~ent invention,
al80 fits tog~er loo ely enough ~o that the oversize cone
and expanslon ~l¢eve ara able to be easily deflected out o:E
true aligN~nt with ~he bolt while being tapped into a
drilled hole tha~ typically may not be ~tr~ight~
3û What ha~ beeal taught9 then, i~ arl expansion anchor
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pirticularly ~uitabl~ or ~30nry ~tructure~ and the
llk~3. The ~xpan~ion ~chor, in ~ccord~nce wi th ~he
prasent inlvention, f~cllltat~, not~bly, a wide ra~ge of
applicatioll~ an~ utlll~y while protriding a relatlvely
5 stmple as~ inexpan~ d~vic~ to ma~ufacture.
~ he form o~E th~3 in~3n~10ns illu~rated and de~s~ribed
herein ~:~e but preferred embodinenlt~ of 'ch~e teachiny~
and th~} form~ curr2n~.1y prefQrred for manufacture. They
are ~hown a~ illu~tration~ of the inventive co~cept~
10 however, r2Lther tha~ by way o limitation, andl it i~
ted out ~hat variou~ mod~ fication~ and &~taration~
~ay b~ indulged in wi1:hin ~he 5cope of the appended clai~
WJM: po
Apr~l 2~; 1976
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