CA2003820A1 - Masonry anchors - Google Patents
Masonry anchorsInfo
- Publication number
- CA2003820A1 CA2003820A1 CA 2003820 CA2003820A CA2003820A1 CA 2003820 A1 CA2003820 A1 CA 2003820A1 CA 2003820 CA2003820 CA 2003820 CA 2003820 A CA2003820 A CA 2003820A CA 2003820 A1 CA2003820 A1 CA 2003820A1
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- thread
- cylindrical
- tapered
- anchor according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000006073 displacement reaction Methods 0.000 claims description 5
- 230000001131 transforming effect Effects 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 8
- 238000000034 method Methods 0.000 description 5
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 238000005461 lubrication Methods 0.000 description 3
- 239000012528 membrane Substances 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 101100532451 Rattus norvegicus Slc22a17 gene Proteins 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920000669 heparin Polymers 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
- F16B13/12—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like
- F16B13/122—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like made from a sheet-metal blank
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
- F16B13/12—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like
- F16B13/124—Separate metal or non-separate or non-metal dowel sleeves fastened by inserting the screw, nail or the like fastened by inserting a threaded element, e.g. screw or bolt
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
- F16B35/00—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws
- F16B35/04—Screw-bolts; Stay-bolts; Screw-threaded studs; Screws; Set screws with specially-shaped head or shaft in order to fix the bolt on or in an object
- F16B35/041—Specially-shaped shafts
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Dowels (AREA)
- Joining Of Building Structures In Genera (AREA)
Abstract
ABSTRACT
A masonry anchor comprises a bolt (2) having a cylindrical thread (2b) leading to a tapered thread (2a). An internally-threaded sleeve (4) comprising segments separated by axial slots is mounted on the end of the bolt and is expanded radially by movement of the tapered thread (2a) through the sleeve (4) to set the anchor into a hole in masonry. In the set condition of the sleeve, the cylindrical thread (2b) of the bolt is within the sleeve and the bolt can be further tightened to draw a component into tight engagement with the masonry surface. The internal thread of the sleeve is a cylindrical thread having substantial compatibility with the cylindrical thread (2b) of the bolt.
A masonry anchor comprises a bolt (2) having a cylindrical thread (2b) leading to a tapered thread (2a). An internally-threaded sleeve (4) comprising segments separated by axial slots is mounted on the end of the bolt and is expanded radially by movement of the tapered thread (2a) through the sleeve (4) to set the anchor into a hole in masonry. In the set condition of the sleeve, the cylindrical thread (2b) of the bolt is within the sleeve and the bolt can be further tightened to draw a component into tight engagement with the masonry surface. The internal thread of the sleeve is a cylindrical thread having substantial compatibility with the cylindrical thread (2b) of the bolt.
Description
~MASONRY ANCHORa~
The present invention relates to a masonry anchor and more particularly to a masonry anchor of the type comprising a threaded sleeve or dowel which engages onto the end of a tapered bolt or stud to be espanded as the bolt or ~tud i~ ariven into the sleeve, to thereby anchor the sleeve within a hole in solid masonry.
E~isting anchors of the type discussed above have conventionally compri~ed an e~pansion element in the form of a bolt which is tapered over a substanti~l portion of its length, with the interior of the sleeve having a matching taper formed with a tapered thread. The ~leeve is ~plit so thbt when ~he ~:
bolt iæ driven into the sleevs, the sleeve progressively espands until it is anchored within the -~;
hole. The tapered thread profile within the slee~e ~ ~ -is compatible with that of the bolt at the start of e~pansion. As the bolt is driven further into the sleeve, the interengaging thread forms become progressively less compatible because of the changing radii~of engaqemenb, and~substantial lubrication iæ ! ~ ~ ', usually required in order to prevent æeizing of the -~
threads. Even with lubrication, the incompatibility of the threads creates large torque requirements on the bolt. In addition, when the sleeve is fully e~panded within the hole, the bolt cannot be ' ~ "
tightened further without applying exces~ive torque.
In many instances, in order to securely anchor a component tightly against the external surface of the ma~onry, the bolt may need to be tightened down beyond the point at which ma~imum e~pansion (full setting) of the sleeve has occurred and accordingly, the operator must either apply the e~cessive torque which will over stress the system and even then may not be sufficient to draw the component firmly down onto the masonry surface, or he must reset the anchor with the sleeve deeper into the hole. -. .. . ..
For convenience, the end of the anchor which lies furthest within the hole will be termed herein -as the "inner end~, and the end of the anchor which lies adjacent the surface of the masonry will be termed herein as the ~outer end~. The ~ame convention will be used when referring to the inner and outer - -~
enas of the sleere and e~pansion element.
- i. ~.,.,.
According to the present invention there is ; ~- -provided a masonry anchor comprising ~n e~pandable ~-sleeve for location in a hole in masonry and an e~pansion element comprising an elongate shank having ; `~- -a substantially cylindrical thread leading to a tapered thread, the sleeve having an internal thread and being defined by a plurality of segments capable of radial displacement, the tapered thread being engageable within the sleeve to cause radial e~pansion of the sleeve by radial displacement of the segments, setting of the sleeve within the hole ; ~-~
occurring when the cylindrical thread of the e~pansion element is substantially within the sleeve whereby the e~pansion element can then be further driven into the sleeve. ;;.
Further according to the present invention there is provided a masonry anchor comprising a sleeve adapted to be espanded into engagement with the circumferential surface of a hole drilled in masonry, and an espansion element insertable into the sleeve to cause such espansion, wherein the e~pansion element comprises a threaded shank having a substantially cylindrical thread portion followed by a tapered thread portion, the sleeve is at least partially split longitudinally and comprises an internal thread engageable with the tapered thread portion of the threaded shank such that as the --.. ~;.
espansion element is screwed into the sleeve the inner end portion of the sleeve espands radially into engagement with the circumferential surface of the hole whereby to set the sleeve within the hole, the sleeve and e~pansion element being so arranged that when the ~leeve is set within the hole the substantially cylindrical thread portion of the - -~
threaded shank is substantially within the sleeve whereby further tightening of.the e~pansion element ~ ;
can occur without further substantial radial -~
e~pansion of the s}eeve, and the thread in the sleeve being such that when the sleeve is e~panded into its set condition the thread assumes a substantially cylindrical form compatible with that of the cylindirica.l thread p~rtion of thejthreaded shank.
In one embodiment, the tapered thread .
defines the inner end portion of the threaded shank and the sleeve is initially mounted on the tapered thread and includes a mating tapered internal thread. :~
.-~ ;, Preferably, the sleeve ~s slit by a plurality of slots e~tending generally a~ially from the inner end of the sleeve, with the slots initially being closed at the inner end and opening as the sleeve e~pands outwardly on setting. ~ -The slots may be formed through the entire wall thickness of the sleeve or alternatively they may e~tend only partially through the wall thickness to leave a web or membrane which is ruptured or torn when the sleeve is e~panded.
, :
Preferably, the sleeve is produced by a method comprising the steps of producing a cylindrical thread form compatible with that of the cylindrical thread portion of the threaded shan~ and deforming the body of the sleeve to produce from the ~ -cylindrical thread form a tapered for~ capable of ; ~-threaded engagement with the tap~red thread at the end portion of the threaded shank. It is ad~antageou8 for the sleeve to be produced by a cold forming operation with the slots formsd only partially ~ ;
through the wall thickness to leave a ~eb or membrane as discussed above. The web or membrane remains at -the inner surface of the sleeve and facilitates threading by tapping the inner surface. ~ ;-In another embodiment, the threaded shank ~
has a further substantially cylindrical thread beyond ;
the tapered thread and of a smaller diameter than the main cylindrical thread, the sleeve initially being mounted on this smaller cylindrical thread and espanding as the tapered thread moves into the sleeve.
, , ;
Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Figure 1 i8 a side view of an anchor ~n ~:
accordance with a first embodiment of the invention;
Figure 2 is a side view of a bolt of ths ~', ;
anchor shown in Figure l;
Figure 3 is a side view of a sleeve of the :~
anchor shown in Figure l;
Figure 4 shows the sleeve as viewed from its inner end;
Figure 5 shows a body from which the sleeve of Figures 3 and 4 is produced; :~
Figure 5a shows to an enlarged scale, interengaging substantially cylindrical thread forms of the sleeve and bolt. `~
; : Figures 6 and 7 are views equivalent to - ~- Figures 3 and 5 of a modified form of sleeve;
Figures 8 and 9 are views equivalent to Figures 3 and 5 of another modified form of sleeve;
: ~ ~ Figure 10 is a side view, partially in section,: of yet:another modified form of sleeve; :~
Figure ll shows the sleeve of Figure 10 after~e~pansion on the bolt;
- ... .. -:
Figure 12 shows a sheet metal blank for forming the sleeve of Figure 11;
... .
Figure 13 is a 3ide view of a bolt of an anchor in accordance with a secona embodiment of the invention;
, Figure 14 shows the end of the bolt of Figure 13 with an e~pansion sleeve mounted thereon;
Figure lS is a plan view of a blank for forming the sleeve of Figure 14; and Figure 16 shows the blank of Figure 15 after partial shaping.
"'~` '' ' '..
As shown in Figures 1 to S of the accompanying drawings, a masonry anchor in accordance with a preferred embodiment with the present invention comprises a bolt 2, having a threaded shank which is tapered at its inner end portion 2a. The ,~ s~
portion 2b of the thr-ad outwardly of the taperea~end ~-portion~2a i8 substantially cylindrical. The thread ' '~',A,',.,''.''".'.'`,' of the portion 2b may be e~actly cylindrical or there may be a very slight taper in the direction of the ` ! I tapered end ~ojrtion 2al The taper ang?e of~the tapered end portion 2a wi}l be dependant on the ! `, ` `' ;`-diameter of the bolt. For small bolts, a taper angle of~up to 24 can be used, and for large bolts, the -~
taper may need to be as low as 3-. This is necessary, ;in order to achieve ma~imum mechanical ad~antage on t~he~one hand, whilst ensuring that the operator can ", ~feel~ that the bolt is sufficiently tight. If the cylindrical portion 2b has a ~light taper, the angle '-, will only be a small fraction of the taper angle of ,,, the portion 2a; for e~ample for a medium sized bolt where the end portion 2a is tapered to an angle of 12, the cylindrical portion 2b can ha~e a ~light ~,, taper of up to 20. The thread tip diameter of the ~' substantially cylindrical thread portion 2b i8 somewhat less than the diameter of the unthreaded portion 2c of the bolt shank for reasons which will '~-~
be discussed later.
The bolt 2 is used with a sleeve 4 (Fiqures ~ , 1, 3 and 4) which is formed from a tubular body 6 (Figure 5) having a wall thickness which progressively increases from itæ outer to its inner end. The body 6 has a cylindrical inner surface 8 and the increasing wall thickness provides a frustoconical outer surface 10 with the larger diameter being at the inner ena of the body 6. The ~ody 6 has a series of angularly-spaced slot$ 12 (as shown, four slots) which e~tend longitudinally from its inner end to a position adjacent the outer end.
The cylindrical inner surface B of the body 6 is ,-, formed with a cylindrical thread which i8 fully compatible with that of the thread on the cylindrical ' portion 2b of the bolt. The sleeve 4 is produced ;;~ ,-from the tubulalr ~ody,j6,by~radial,ly compressing,the body 6 at its inner end. This deformation is accommodated by closure of the inner end portions of the slots 12 as is shown in Figures 3 and 4. The deformation has the effect of transforming the outer frustoconical surface 10 into a cylindrical outer surface on the sleeve 4 and transforming the threaded ' ,'~
: ;
inner cylindrical surface 8 into a conical surface, the angle of which corresponds to the angle of the tapered end portion 2a of the bolt. The thread within the sleeve, thus becomes a tapered thread.
The overall length of the slee~e 4 i8 ~pprosimately -~
equal to the length of the tapered end portion 2a of the bolt and the outer diameter of the sleeve 4 in its radially compressed state is approsimately equal to the diameter of the unthreaded shank portion 2c of the bolt. This latter relationship means that the diameter of the shank portion 2c can be substantially the same as the diameter of the hole in the masonry whereby the shank diameter can be a ma~imum for a given hole size which provides improved torque-carrying characteristics for the bolt. ~ -In order to set the anchor, the tapered end portion 2a of the bolt is initially screwe~ into the tapered thread in the sleeve 4 which ha~ been formed during manufacture by radially compreJsing the outer end of the body 6 as discussed above. As the tapered sleeve thread was originally formed as a cylindrical thread there will initially be a degree of thread mismatch between the tapered thread in the sleeve ~nd the tapered thread on the bolt. However, this mismatch occurs at a point where the torque requirements are a minimum and the mismatch progresiively reduces as the torque requirements increase, as will be described. In contrast, in the esisting anchors discussed earlier, the thread compatibility is a masimum at minimum torque requirements and the threads increasingly mismatch as the torque reguirements increase. With the slee~e 4 screwed onto the tapered end portion 2a of the bolt, --~
- ~"
' .
the sleeve and bolt are inserted into the hole with the sleeve frictionally engaging the wall of the hole. Screwing of the bolt down into the sleeve causes the tapered portion 2a to move down through the sleeve and thereby espand the sleeve radi~lly at its inner end by opening the 810t8 12 at that end.
As the tapered portion 2a starts to move through the sleeve in order to e~pand the slee~e radially at its inner end, the cylindrical thread portion 2b of the bolt starts to move into the outer end of the sleeve. At the designated ma~imum espansion of the sleeve which provides the desired degree of setting of the sleeve within the hole, the tapered end portion 2a of the bolt has moved beyond the sleeve, and the sleeve is wholly engaged with the cylindrical thread portion 2b of the bolt.
It will be appreciated as the sleeve espands radially outwardly at its inner end, ita threaaed -inner surface will tend to return in shape towards ;~-its original cylindrical shape and at the point of ma~imum espansion when the tapered threaa portion 2a -is beyond the sleeve, the interior surface of the sleeve will have returned to its original cylindrical shape where there is complete thread compatibility between the original cylindrical thread formed in the sleeve and the cylindrical thread on the bolt and such compatibility esists at the masimum torque ~ -~
requirement corresponding to masimum espansion. The ~;u~
use of the interengaging thread forms which are substantially cylindrical at the point of masimum espansion means that when the sleeve has been fully set within the hole, the bolt can still be screwed further down into the sleeve without further - ~
" , ,-;
increasing the torque requirements. Accordingly, even although the sleeve has been fully set, the bolt may be screwed down further into the sleeve in order to draw the component firmly against the surface of the masonry without the use of additional and escessive torque requirements. The compatibility of the interengaging threads at setting of the sleeve also means that the torque requirements on the bolt for a required setting force are significantly less than with the existing anchors and minimal lubrication is required. The use of a bolt shank diameter which is a ma~imum for a given size of hole means that the shear carrying characteristics of the ~-bolt are also a ma~imum. The reduced torque requirements and the ma~imum shear load characteristics obviate the need for special heat treatments to be applied to the bolt for strengthening purposes.
With conventional v-thread forms there ~ends to be a wedging action between the opposed flanks of the male thread portion and the corresponding flanks of the female portion. In the thread mechanism of the anchor under consideration there are very substantial radial forces between the interenqaging threads due to the e~pansion effect which forces the sleeve radially outwards into contact with the wall of the ~ole. IIf tlhe t,hrleads on the bolt and sleeve were conventional v-threads, the radial forces would tend to cause wedging to occur between the interengaging threads which would give rise to large torque requirements on the bolt. In order to avoid this effect, as shown in Figure 5a the interengaging ~-threads are preferably so related that an a~ial gap e~ists between the trailing flank 20 of the male bolt thread and the adjacent flank 22 of the corresponding female thread section in the sleeve 4. In addition, the root surface area 24 of the female thread section of the bolt and the corresponding tip area 26 of the male thread section of the sleeve thread are made relatively large and in contact so that a significant component of the radial load is carried by these surfaces. In this manner the high radial loads necessary to effect e~pansion and setting of the sleeve in the hole does not result in high friction between the interengaging threads and hence high torque requirements on tightening. It will be appreciated that this effect can be achieved by thread forms of other than the specific shape shown.
For e~ample these effects can be achieved by thread forms which are sinuous rather than rectilinear, and ;~
again the arrangement would be such that at the trailing edge there i~ a space between the opposing flanks and there is al80 a substantial root~tip contact area to carry the high radial loading.
As e~plained above, the thread in the sleeve is initially formed as a cylindrical thread which i8 deformed into a tapered thread by radially compressing the inner end of the sleeve. Apart from the substantial advantages in operation which arise from this as previously discussed, manufacture of the sleeve is also facilitated. The thread, being à ! '~
cylindrical thread, can be formed by means of conventional thread forming techniques with the cylindrical thread being converted into a tapered thread by a simple radial compression of the sleeve and this technique is significantly simpler than the techniques necessary for forming tapered threads as occurs in the e~isting anchors.
There is shown in Figure 6 a modified form of sleeve, designated 28. The tubular body 30 ; ~, ~Figure 7) from which the sleeve 28 i8 formed i8 of stepped outer profile comprising a cylindrical surface 32 of larger diameter at its inner end with the main body portion 34 being of cylindrical form of smaller diameter. The body is formed with an internal cylindrical thread and slots 36 equivalent to the slots 12 of the sleeve of Figures 4 and 5. To produce the sleeve 28, the body 30 is radially compressed at its inner end portion such that the surface 32 remains cylindrical after compression with the remainder of the body portion 34 tapering towards that end in order to provide the tapered thread within the sleeve. The cylindrical surface 32 of the sleeve after compression is of substantially the same diameter as the outer end of the sleeve. When the sleeve is set into the hole there i8 initially a large cylindrical contact area (provided by the surface 32) available at the inner end of the sleeve for contact with the wall of the hole during initial e~pansion of the sIeeve and this area carries the whole of the radial holding.
The sleeve 38 shown in Figure 8 is formed from altubular body 40 (Figure 9) having an internal cylindrical thread and slots 41 e~tending from its inner end. The inner end portion 42 of the body is cylindrical with the main body portion 44 having a --~
progressive taper. When the body 40 is radially compressed at its inner end to form the tapered thread, the main body portion 44 of the sleeve becomes cylindrical with the inner end portion 42 being of frustoconical form. Upon subsequent espansion on setting of the sleeve in the hole, the inner end portion 42 returns to a subgtantially cylindrical form which provides a large surface area to carry most of the radial loading, with the then frustoconical main body portion 44 carrying the remainder of the radial loading.
''' ~
The sleeve 48 shown in Figures 10 and 11 can be formed from a flat metal blank 50 (Figure 12) on which a cylindrical thread 52 is produced by a rolling or coining process. The blank 50 is then pressed into the form of a generally conical slotted sleeve with end portions 53 of the blan~ being bent -to lie e~ternally of the sleeve to provide an increased thic~ness at its inner end portion 80 as to permit the necessary setting effect on e~pansion. ;~
The slee~e is e~panded at itæ inner ena portion by the bolt in substantially the same way as discussed -~ `
in relation to the first embodiment.
It is not essential for the bolt to be a headed bolt and may alternatively be threaded along its entire length! thus forming a stud.
In the embodiment shown in Figures 13 to 15, ;
the boit comprises an additional cylindrical portion 2d a~ the end of the tapered portion 2a and of reduced diameter relative to the main cylindrical thread portion 2b. In this embodiment, the sleeve 60 ;~
comprises two (or more) segments 62 of ;-~
part-cylindricaI form and which are separated by ': '';' ;: '.
,'. . :: . ::', ~, ,:. `, ..
1 5 .~
longitudinal slots 64 extending the length of the ,' sleeve so that each segment 62 can be displaced as a whole from a smaller to a larger diameter by opening of the slots 64 throughout their length. Although the segments are essentially separate segments, they are held in assembled relation by bridging port~on~ 66 e~tending forwardly of the segments. The bridging portions 66 are of a structure such that they permit the segments 62 to displace each relative to the other as a whole by opening of the slots 64. The sleeve 60 is formed with a cylindrical thread which mates with the cylindrical thread portion 2d at the end of the bolt and the sleeve 60 is mounted on the bolt by engagement with that thread portion. The thickness of the sleeve 60 is such that when the `
sleeve i8 mounted on the cylindrical thread portion 2d the outer surface 68 of the sleeve lies at a ~-diameter equivalent to the diameter of the masonry ~ '~
hole. It will be noted that in this embodiment the unespanded sleeve is mounted on a cylindrical thread -~
on the bolt rather than on a tape~ed thread and accordingly, the sleeve does not require a thread which is initially tapered.
~.
When the anchor is inserted into the hole ,~
and the bolt is rotated, the tapered thread portion 2a moves into the sleeve 60 to cause e~pansion of the ,~
sleeve.l!As,the",t,aplered,p,or!tion en,te,rs the sleevq 60, the segments 62 will tilt relative to each other by opening of the slots 64 so that the thread within the sleeve becomes a tapered thread compatible to a degree with that of the tapered bolt thread. As the larger cylindrical thread portion 2b moves into the ; `,`~
sleeve 60, the segments 62 displace into parallel ,~ s~
.; ~ .., -.., , ' ' ~ -relationship so that the thread of the sleeve transforms back into a cylindrical thread, but at a larger diameter commensurate with that of the larger diameter cylindrical thread of the bolt. Although the thread diameter of the main cylindric~l portion 2b of the bolt is larger than that of the snaller diameter end portion 2d, the thread is at the same pitch and the cylindrical thread of the sleeve will cooperate satisfactorily with both the smaller and larger diameter cylindrical threads of the bolt.
This form of sleeve in which the segments of -the sleeve are essentially separate segments, can be fabricated from a thinner material than the sleeve of the preceding embodiments in which the outer end of the sleeve is of continuous form in order to connect the sleeve segments. The reduced thicbness of the sleeve in thi~ embodiment means that the required e~pansion of the sleeve can be achieved with a larger diameter main cylindrical thread of the bolt whereby this portion of the bolt is of an incrcased strength.
Although when the sleeve has e~panded onto the main cylindrical portion 2b of the bolt, there will be a slight mismatch between the e~panded ~leeve ana the bolt, as the thread pitch of the cylindrical thread on the bolt is the same as that of the cylindrical thread on the sleeve, there will still be sub~tantial -~
compatibility between the interengaging threads. When ~ -the sleeve is in its unespanded state on the smaller ` -diameter thread portion 2d, the sleeve is not e~actly ;
cylindrical, but rather, is slightly out of round in order to prevent rotation of the sleeve within the hole as the bolt starts to be screwed into the ~ ~ -sleeve. Alternatively, the sleeve can be formed with -, anti-rot~tion lugs which engage the surrounding surface of the hole.
The sleeve is preferably formed from a sheet metal blank 70 as shown in Figure 15 having end portions 72 which can be deformed as shown in Figure 16 to form the two semi-cylindrical segments 62, the end portions 72 being interconnected by the bridging :-portions ~6 and having a thread form as shown at 74.
The partially deformed blank of Figure 16 is then folded so that the semi-cylindrical segments 62 lie -side by side to define the cylindrical sleeve, such folding being accommodated by bending of the bridging ~ :
portions 66. The bridging portions include a~ially :~ :
spaced notches 76 whereby the bridging portions preferentially bend in the area of the notches to assume the shape shown in Figure 14. ::-The anchors described herein provide a :::-.
relatiYely high contact area between the ~leeve and the masonry which provides a rigid ~etting which can be displaced only upon application of a very ;~
substantial load. Despite this effect, the bolt can ~,h,,'.'-still be tightened further after setting to ~uch an ~ !`,'~''' estent as is necessary to draw the component into tight engagement with the outer surface of masonry. .
, , The ~e,mbodiments,have been described by way of example only and modifications are possible within : ~
the scope of the invention. ~ '' ,~ ",' : :
~:
The present invention relates to a masonry anchor and more particularly to a masonry anchor of the type comprising a threaded sleeve or dowel which engages onto the end of a tapered bolt or stud to be espanded as the bolt or ~tud i~ ariven into the sleeve, to thereby anchor the sleeve within a hole in solid masonry.
E~isting anchors of the type discussed above have conventionally compri~ed an e~pansion element in the form of a bolt which is tapered over a substanti~l portion of its length, with the interior of the sleeve having a matching taper formed with a tapered thread. The ~leeve is ~plit so thbt when ~he ~:
bolt iæ driven into the sleevs, the sleeve progressively espands until it is anchored within the -~;
hole. The tapered thread profile within the slee~e ~ ~ -is compatible with that of the bolt at the start of e~pansion. As the bolt is driven further into the sleeve, the interengaging thread forms become progressively less compatible because of the changing radii~of engaqemenb, and~substantial lubrication iæ ! ~ ~ ', usually required in order to prevent æeizing of the -~
threads. Even with lubrication, the incompatibility of the threads creates large torque requirements on the bolt. In addition, when the sleeve is fully e~panded within the hole, the bolt cannot be ' ~ "
tightened further without applying exces~ive torque.
In many instances, in order to securely anchor a component tightly against the external surface of the ma~onry, the bolt may need to be tightened down beyond the point at which ma~imum e~pansion (full setting) of the sleeve has occurred and accordingly, the operator must either apply the e~cessive torque which will over stress the system and even then may not be sufficient to draw the component firmly down onto the masonry surface, or he must reset the anchor with the sleeve deeper into the hole. -. .. . ..
For convenience, the end of the anchor which lies furthest within the hole will be termed herein -as the "inner end~, and the end of the anchor which lies adjacent the surface of the masonry will be termed herein as the ~outer end~. The ~ame convention will be used when referring to the inner and outer - -~
enas of the sleere and e~pansion element.
- i. ~.,.,.
According to the present invention there is ; ~- -provided a masonry anchor comprising ~n e~pandable ~-sleeve for location in a hole in masonry and an e~pansion element comprising an elongate shank having ; `~- -a substantially cylindrical thread leading to a tapered thread, the sleeve having an internal thread and being defined by a plurality of segments capable of radial displacement, the tapered thread being engageable within the sleeve to cause radial e~pansion of the sleeve by radial displacement of the segments, setting of the sleeve within the hole ; ~-~
occurring when the cylindrical thread of the e~pansion element is substantially within the sleeve whereby the e~pansion element can then be further driven into the sleeve. ;;.
Further according to the present invention there is provided a masonry anchor comprising a sleeve adapted to be espanded into engagement with the circumferential surface of a hole drilled in masonry, and an espansion element insertable into the sleeve to cause such espansion, wherein the e~pansion element comprises a threaded shank having a substantially cylindrical thread portion followed by a tapered thread portion, the sleeve is at least partially split longitudinally and comprises an internal thread engageable with the tapered thread portion of the threaded shank such that as the --.. ~;.
espansion element is screwed into the sleeve the inner end portion of the sleeve espands radially into engagement with the circumferential surface of the hole whereby to set the sleeve within the hole, the sleeve and e~pansion element being so arranged that when the ~leeve is set within the hole the substantially cylindrical thread portion of the - -~
threaded shank is substantially within the sleeve whereby further tightening of.the e~pansion element ~ ;
can occur without further substantial radial -~
e~pansion of the s}eeve, and the thread in the sleeve being such that when the sleeve is e~panded into its set condition the thread assumes a substantially cylindrical form compatible with that of the cylindirica.l thread p~rtion of thejthreaded shank.
In one embodiment, the tapered thread .
defines the inner end portion of the threaded shank and the sleeve is initially mounted on the tapered thread and includes a mating tapered internal thread. :~
.-~ ;, Preferably, the sleeve ~s slit by a plurality of slots e~tending generally a~ially from the inner end of the sleeve, with the slots initially being closed at the inner end and opening as the sleeve e~pands outwardly on setting. ~ -The slots may be formed through the entire wall thickness of the sleeve or alternatively they may e~tend only partially through the wall thickness to leave a web or membrane which is ruptured or torn when the sleeve is e~panded.
, :
Preferably, the sleeve is produced by a method comprising the steps of producing a cylindrical thread form compatible with that of the cylindrical thread portion of the threaded shan~ and deforming the body of the sleeve to produce from the ~ -cylindrical thread form a tapered for~ capable of ; ~-threaded engagement with the tap~red thread at the end portion of the threaded shank. It is ad~antageou8 for the sleeve to be produced by a cold forming operation with the slots formsd only partially ~ ;
through the wall thickness to leave a ~eb or membrane as discussed above. The web or membrane remains at -the inner surface of the sleeve and facilitates threading by tapping the inner surface. ~ ;-In another embodiment, the threaded shank ~
has a further substantially cylindrical thread beyond ;
the tapered thread and of a smaller diameter than the main cylindrical thread, the sleeve initially being mounted on this smaller cylindrical thread and espanding as the tapered thread moves into the sleeve.
, , ;
Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:
Figure 1 i8 a side view of an anchor ~n ~:
accordance with a first embodiment of the invention;
Figure 2 is a side view of a bolt of ths ~', ;
anchor shown in Figure l;
Figure 3 is a side view of a sleeve of the :~
anchor shown in Figure l;
Figure 4 shows the sleeve as viewed from its inner end;
Figure 5 shows a body from which the sleeve of Figures 3 and 4 is produced; :~
Figure 5a shows to an enlarged scale, interengaging substantially cylindrical thread forms of the sleeve and bolt. `~
; : Figures 6 and 7 are views equivalent to - ~- Figures 3 and 5 of a modified form of sleeve;
Figures 8 and 9 are views equivalent to Figures 3 and 5 of another modified form of sleeve;
: ~ ~ Figure 10 is a side view, partially in section,: of yet:another modified form of sleeve; :~
Figure ll shows the sleeve of Figure 10 after~e~pansion on the bolt;
- ... .. -:
Figure 12 shows a sheet metal blank for forming the sleeve of Figure 11;
... .
Figure 13 is a 3ide view of a bolt of an anchor in accordance with a secona embodiment of the invention;
, Figure 14 shows the end of the bolt of Figure 13 with an e~pansion sleeve mounted thereon;
Figure lS is a plan view of a blank for forming the sleeve of Figure 14; and Figure 16 shows the blank of Figure 15 after partial shaping.
"'~` '' ' '..
As shown in Figures 1 to S of the accompanying drawings, a masonry anchor in accordance with a preferred embodiment with the present invention comprises a bolt 2, having a threaded shank which is tapered at its inner end portion 2a. The ,~ s~
portion 2b of the thr-ad outwardly of the taperea~end ~-portion~2a i8 substantially cylindrical. The thread ' '~',A,',.,''.''".'.'`,' of the portion 2b may be e~actly cylindrical or there may be a very slight taper in the direction of the ` ! I tapered end ~ojrtion 2al The taper ang?e of~the tapered end portion 2a wi}l be dependant on the ! `, ` `' ;`-diameter of the bolt. For small bolts, a taper angle of~up to 24 can be used, and for large bolts, the -~
taper may need to be as low as 3-. This is necessary, ;in order to achieve ma~imum mechanical ad~antage on t~he~one hand, whilst ensuring that the operator can ", ~feel~ that the bolt is sufficiently tight. If the cylindrical portion 2b has a ~light taper, the angle '-, will only be a small fraction of the taper angle of ,,, the portion 2a; for e~ample for a medium sized bolt where the end portion 2a is tapered to an angle of 12, the cylindrical portion 2b can ha~e a ~light ~,, taper of up to 20. The thread tip diameter of the ~' substantially cylindrical thread portion 2b i8 somewhat less than the diameter of the unthreaded portion 2c of the bolt shank for reasons which will '~-~
be discussed later.
The bolt 2 is used with a sleeve 4 (Fiqures ~ , 1, 3 and 4) which is formed from a tubular body 6 (Figure 5) having a wall thickness which progressively increases from itæ outer to its inner end. The body 6 has a cylindrical inner surface 8 and the increasing wall thickness provides a frustoconical outer surface 10 with the larger diameter being at the inner ena of the body 6. The ~ody 6 has a series of angularly-spaced slot$ 12 (as shown, four slots) which e~tend longitudinally from its inner end to a position adjacent the outer end.
The cylindrical inner surface B of the body 6 is ,-, formed with a cylindrical thread which i8 fully compatible with that of the thread on the cylindrical ' portion 2b of the bolt. The sleeve 4 is produced ;;~ ,-from the tubulalr ~ody,j6,by~radial,ly compressing,the body 6 at its inner end. This deformation is accommodated by closure of the inner end portions of the slots 12 as is shown in Figures 3 and 4. The deformation has the effect of transforming the outer frustoconical surface 10 into a cylindrical outer surface on the sleeve 4 and transforming the threaded ' ,'~
: ;
inner cylindrical surface 8 into a conical surface, the angle of which corresponds to the angle of the tapered end portion 2a of the bolt. The thread within the sleeve, thus becomes a tapered thread.
The overall length of the slee~e 4 i8 ~pprosimately -~
equal to the length of the tapered end portion 2a of the bolt and the outer diameter of the sleeve 4 in its radially compressed state is approsimately equal to the diameter of the unthreaded shank portion 2c of the bolt. This latter relationship means that the diameter of the shank portion 2c can be substantially the same as the diameter of the hole in the masonry whereby the shank diameter can be a ma~imum for a given hole size which provides improved torque-carrying characteristics for the bolt. ~ -In order to set the anchor, the tapered end portion 2a of the bolt is initially screwe~ into the tapered thread in the sleeve 4 which ha~ been formed during manufacture by radially compreJsing the outer end of the body 6 as discussed above. As the tapered sleeve thread was originally formed as a cylindrical thread there will initially be a degree of thread mismatch between the tapered thread in the sleeve ~nd the tapered thread on the bolt. However, this mismatch occurs at a point where the torque requirements are a minimum and the mismatch progresiively reduces as the torque requirements increase, as will be described. In contrast, in the esisting anchors discussed earlier, the thread compatibility is a masimum at minimum torque requirements and the threads increasingly mismatch as the torque reguirements increase. With the slee~e 4 screwed onto the tapered end portion 2a of the bolt, --~
- ~"
' .
the sleeve and bolt are inserted into the hole with the sleeve frictionally engaging the wall of the hole. Screwing of the bolt down into the sleeve causes the tapered portion 2a to move down through the sleeve and thereby espand the sleeve radi~lly at its inner end by opening the 810t8 12 at that end.
As the tapered portion 2a starts to move through the sleeve in order to e~pand the slee~e radially at its inner end, the cylindrical thread portion 2b of the bolt starts to move into the outer end of the sleeve. At the designated ma~imum espansion of the sleeve which provides the desired degree of setting of the sleeve within the hole, the tapered end portion 2a of the bolt has moved beyond the sleeve, and the sleeve is wholly engaged with the cylindrical thread portion 2b of the bolt.
It will be appreciated as the sleeve espands radially outwardly at its inner end, ita threaaed -inner surface will tend to return in shape towards ;~-its original cylindrical shape and at the point of ma~imum espansion when the tapered threaa portion 2a -is beyond the sleeve, the interior surface of the sleeve will have returned to its original cylindrical shape where there is complete thread compatibility between the original cylindrical thread formed in the sleeve and the cylindrical thread on the bolt and such compatibility esists at the masimum torque ~ -~
requirement corresponding to masimum espansion. The ~;u~
use of the interengaging thread forms which are substantially cylindrical at the point of masimum espansion means that when the sleeve has been fully set within the hole, the bolt can still be screwed further down into the sleeve without further - ~
" , ,-;
increasing the torque requirements. Accordingly, even although the sleeve has been fully set, the bolt may be screwed down further into the sleeve in order to draw the component firmly against the surface of the masonry without the use of additional and escessive torque requirements. The compatibility of the interengaging threads at setting of the sleeve also means that the torque requirements on the bolt for a required setting force are significantly less than with the existing anchors and minimal lubrication is required. The use of a bolt shank diameter which is a ma~imum for a given size of hole means that the shear carrying characteristics of the ~-bolt are also a ma~imum. The reduced torque requirements and the ma~imum shear load characteristics obviate the need for special heat treatments to be applied to the bolt for strengthening purposes.
With conventional v-thread forms there ~ends to be a wedging action between the opposed flanks of the male thread portion and the corresponding flanks of the female portion. In the thread mechanism of the anchor under consideration there are very substantial radial forces between the interenqaging threads due to the e~pansion effect which forces the sleeve radially outwards into contact with the wall of the ~ole. IIf tlhe t,hrleads on the bolt and sleeve were conventional v-threads, the radial forces would tend to cause wedging to occur between the interengaging threads which would give rise to large torque requirements on the bolt. In order to avoid this effect, as shown in Figure 5a the interengaging ~-threads are preferably so related that an a~ial gap e~ists between the trailing flank 20 of the male bolt thread and the adjacent flank 22 of the corresponding female thread section in the sleeve 4. In addition, the root surface area 24 of the female thread section of the bolt and the corresponding tip area 26 of the male thread section of the sleeve thread are made relatively large and in contact so that a significant component of the radial load is carried by these surfaces. In this manner the high radial loads necessary to effect e~pansion and setting of the sleeve in the hole does not result in high friction between the interengaging threads and hence high torque requirements on tightening. It will be appreciated that this effect can be achieved by thread forms of other than the specific shape shown.
For e~ample these effects can be achieved by thread forms which are sinuous rather than rectilinear, and ;~
again the arrangement would be such that at the trailing edge there i~ a space between the opposing flanks and there is al80 a substantial root~tip contact area to carry the high radial loading.
As e~plained above, the thread in the sleeve is initially formed as a cylindrical thread which i8 deformed into a tapered thread by radially compressing the inner end of the sleeve. Apart from the substantial advantages in operation which arise from this as previously discussed, manufacture of the sleeve is also facilitated. The thread, being à ! '~
cylindrical thread, can be formed by means of conventional thread forming techniques with the cylindrical thread being converted into a tapered thread by a simple radial compression of the sleeve and this technique is significantly simpler than the techniques necessary for forming tapered threads as occurs in the e~isting anchors.
There is shown in Figure 6 a modified form of sleeve, designated 28. The tubular body 30 ; ~, ~Figure 7) from which the sleeve 28 i8 formed i8 of stepped outer profile comprising a cylindrical surface 32 of larger diameter at its inner end with the main body portion 34 being of cylindrical form of smaller diameter. The body is formed with an internal cylindrical thread and slots 36 equivalent to the slots 12 of the sleeve of Figures 4 and 5. To produce the sleeve 28, the body 30 is radially compressed at its inner end portion such that the surface 32 remains cylindrical after compression with the remainder of the body portion 34 tapering towards that end in order to provide the tapered thread within the sleeve. The cylindrical surface 32 of the sleeve after compression is of substantially the same diameter as the outer end of the sleeve. When the sleeve is set into the hole there i8 initially a large cylindrical contact area (provided by the surface 32) available at the inner end of the sleeve for contact with the wall of the hole during initial e~pansion of the sIeeve and this area carries the whole of the radial holding.
The sleeve 38 shown in Figure 8 is formed from altubular body 40 (Figure 9) having an internal cylindrical thread and slots 41 e~tending from its inner end. The inner end portion 42 of the body is cylindrical with the main body portion 44 having a --~
progressive taper. When the body 40 is radially compressed at its inner end to form the tapered thread, the main body portion 44 of the sleeve becomes cylindrical with the inner end portion 42 being of frustoconical form. Upon subsequent espansion on setting of the sleeve in the hole, the inner end portion 42 returns to a subgtantially cylindrical form which provides a large surface area to carry most of the radial loading, with the then frustoconical main body portion 44 carrying the remainder of the radial loading.
''' ~
The sleeve 48 shown in Figures 10 and 11 can be formed from a flat metal blank 50 (Figure 12) on which a cylindrical thread 52 is produced by a rolling or coining process. The blank 50 is then pressed into the form of a generally conical slotted sleeve with end portions 53 of the blan~ being bent -to lie e~ternally of the sleeve to provide an increased thic~ness at its inner end portion 80 as to permit the necessary setting effect on e~pansion. ;~
The slee~e is e~panded at itæ inner ena portion by the bolt in substantially the same way as discussed -~ `
in relation to the first embodiment.
It is not essential for the bolt to be a headed bolt and may alternatively be threaded along its entire length! thus forming a stud.
In the embodiment shown in Figures 13 to 15, ;
the boit comprises an additional cylindrical portion 2d a~ the end of the tapered portion 2a and of reduced diameter relative to the main cylindrical thread portion 2b. In this embodiment, the sleeve 60 ;~
comprises two (or more) segments 62 of ;-~
part-cylindricaI form and which are separated by ': '';' ;: '.
,'. . :: . ::', ~, ,:. `, ..
1 5 .~
longitudinal slots 64 extending the length of the ,' sleeve so that each segment 62 can be displaced as a whole from a smaller to a larger diameter by opening of the slots 64 throughout their length. Although the segments are essentially separate segments, they are held in assembled relation by bridging port~on~ 66 e~tending forwardly of the segments. The bridging portions 66 are of a structure such that they permit the segments 62 to displace each relative to the other as a whole by opening of the slots 64. The sleeve 60 is formed with a cylindrical thread which mates with the cylindrical thread portion 2d at the end of the bolt and the sleeve 60 is mounted on the bolt by engagement with that thread portion. The thickness of the sleeve 60 is such that when the `
sleeve i8 mounted on the cylindrical thread portion 2d the outer surface 68 of the sleeve lies at a ~-diameter equivalent to the diameter of the masonry ~ '~
hole. It will be noted that in this embodiment the unespanded sleeve is mounted on a cylindrical thread -~
on the bolt rather than on a tape~ed thread and accordingly, the sleeve does not require a thread which is initially tapered.
~.
When the anchor is inserted into the hole ,~
and the bolt is rotated, the tapered thread portion 2a moves into the sleeve 60 to cause e~pansion of the ,~
sleeve.l!As,the",t,aplered,p,or!tion en,te,rs the sleevq 60, the segments 62 will tilt relative to each other by opening of the slots 64 so that the thread within the sleeve becomes a tapered thread compatible to a degree with that of the tapered bolt thread. As the larger cylindrical thread portion 2b moves into the ; `,`~
sleeve 60, the segments 62 displace into parallel ,~ s~
.; ~ .., -.., , ' ' ~ -relationship so that the thread of the sleeve transforms back into a cylindrical thread, but at a larger diameter commensurate with that of the larger diameter cylindrical thread of the bolt. Although the thread diameter of the main cylindric~l portion 2b of the bolt is larger than that of the snaller diameter end portion 2d, the thread is at the same pitch and the cylindrical thread of the sleeve will cooperate satisfactorily with both the smaller and larger diameter cylindrical threads of the bolt.
This form of sleeve in which the segments of -the sleeve are essentially separate segments, can be fabricated from a thinner material than the sleeve of the preceding embodiments in which the outer end of the sleeve is of continuous form in order to connect the sleeve segments. The reduced thicbness of the sleeve in thi~ embodiment means that the required e~pansion of the sleeve can be achieved with a larger diameter main cylindrical thread of the bolt whereby this portion of the bolt is of an incrcased strength.
Although when the sleeve has e~panded onto the main cylindrical portion 2b of the bolt, there will be a slight mismatch between the e~panded ~leeve ana the bolt, as the thread pitch of the cylindrical thread on the bolt is the same as that of the cylindrical thread on the sleeve, there will still be sub~tantial -~
compatibility between the interengaging threads. When ~ -the sleeve is in its unespanded state on the smaller ` -diameter thread portion 2d, the sleeve is not e~actly ;
cylindrical, but rather, is slightly out of round in order to prevent rotation of the sleeve within the hole as the bolt starts to be screwed into the ~ ~ -sleeve. Alternatively, the sleeve can be formed with -, anti-rot~tion lugs which engage the surrounding surface of the hole.
The sleeve is preferably formed from a sheet metal blank 70 as shown in Figure 15 having end portions 72 which can be deformed as shown in Figure 16 to form the two semi-cylindrical segments 62, the end portions 72 being interconnected by the bridging :-portions ~6 and having a thread form as shown at 74.
The partially deformed blank of Figure 16 is then folded so that the semi-cylindrical segments 62 lie -side by side to define the cylindrical sleeve, such folding being accommodated by bending of the bridging ~ :
portions 66. The bridging portions include a~ially :~ :
spaced notches 76 whereby the bridging portions preferentially bend in the area of the notches to assume the shape shown in Figure 14. ::-The anchors described herein provide a :::-.
relatiYely high contact area between the ~leeve and the masonry which provides a rigid ~etting which can be displaced only upon application of a very ;~
substantial load. Despite this effect, the bolt can ~,h,,'.'-still be tightened further after setting to ~uch an ~ !`,'~''' estent as is necessary to draw the component into tight engagement with the outer surface of masonry. .
, , The ~e,mbodiments,have been described by way of example only and modifications are possible within : ~
the scope of the invention. ~ '' ,~ ",' : :
~:
Claims (20)
1. A masonry anchor comprising an expandable sleeve for location in a hole in masonry and an expansion element comprising an elongate shank having a substantially cylindrical thread leading to a tapered thread, the sleeve having an internal thread and being defined by a plurality of segments capable of radial displacement, the tapered thread being engageable within the sleeve to cause radial expansion of the sleeve by radial displacement of the segments, setting of the sleeve within the hole occurring when the cylindrical thread of the expansion element is substantially within the sleeve whereby the expansion element can then be further driven into the sleeve.
2. A masonry anchor according to Claim 1, wherein the thread in the sleeve is such that in the expanded state of the sleeve when the sleeve is on the cylindrical thread of the expansion element the thread of the sleeve has substantial compatibility with the cylindrical thread.
3. A masonry anchor according to Claim 2, wherein the tapered thread is at the end of the expansion element and the internal surface of the sleeve is conical whereby the thread in the sleeve is tapered to mate with the tapered thread, the conical internal surface of the sleeve displacing into a cylindrical surface upon radial expansion of the sleeve segments as the cylindrical thread of the expansion element moves into the sleeve whereby the internal thread in the sleeve transforms into a cylindrical thread compatible with that of the expansion element.
4. A masonry anchor according to Claim 3, wherein the sleeve is initially formed with an internal cylindrical thread compatible with that of the cylindrical thread on the expansion element and the sleeve is then deformed to transform the cylindrical thread into a tapered thread to mate with the tapered thread on the expansion element prior to setting of the sleeve within the hole.
5. A masonry anchor according to Claim 3 or Claim 4, wherein the wall thickness of the sleeve at the inner end of the sleeve is greater than that at the outer end of the sleeve.
6. A masonry anchor according to Claim 5, wherein in the deformed state of the sleeve the external surface of the inner end portion of the sleeve is of cylindrical form.
7. A masonry anchor according to Claim 5, wherein in the deformed state of the sleeve, the external surface of the sleeve at the inner end portion is of frustoconical form tapering towards the inner end of the sleeve, the frustoconical surface portion transforming into a substantially cylindrical surface upon subsequent expansion of the sleeve by radial displacement of the segments.
8. An anchor according to any one of Claim 4 to 7, wherein the segments of the sleeve are defined by slots extending longitudinally of the sleeve from the inner end of the sleeve to positions adjacent the outer end of the sleeve with the slots being closed at that end.
9. An anchor according to Claim 8, wherein the sleeve is deformed to define the tapered thread by radially compressing the inner end portion of the sleeve whereby to narrow the slots at that end portion.
10. A masonry anchor according to Claim 1 or Claim 2, wherein the expansion element comprises a second cylindrical thread at the inner end of the tapered thread, said second cylindrical thread being of a reduced diameter relative to the first cylindrical thread, the sleeve being initially received on the second cylindrical thread and being radially expanded as the tapered thread moves into the sleeve.
11. A masonry anchor according to Claim 10, wherein the segments are defined by longitudinal slots extending the length of the sleeve whereby the sleeve can move from the second cylindrical thread onto the first cylindrical thread of the expansion element by radial expansion of the sleeve by opening of the slots along the entire length of the slots as the tapered thread moves through the sleeve.
12. A masonry anchor according to Claim 10 or Claim 11, wherein the first and second cylindrical threads of the expansion element have a pitch equivalent to that of the thread of the sleeve whereby the thread of the sleeve has substantial compatibility with both cylindrical threads.
13. A masonry anchor according to any one of Claims 10 to 12, wherein the segments are held in assembled relationship by deformable bridging portions interconnecting the segments at a position beyond the inner end of the sleeve.
14. A masonry anchor comprising a sleeve adapted to be expanded into engagement with the circumferential surface of a hole drilled in masonry, and an expansion element insertable into the sleeve to cause such expansion, wherein the expansion element comprises a threaded shank having a substantially cylindrical thread portion followed by a tapered thread portion, the sleeve is at least partially split longitudinally and comprises an internal thread engageable with the tapered thread portion of the threaded shank such that as the expansion element is screwed into the sleeve the inner end portion of the sleeve expands radially into engagement with the circumferential surface of the hole whereby to set the sleeve within the hole, the sleeve and wxpansion element being so arranged that when the sleeve is set within the hole the substantially cylindrical thread portion of the threaded shank is substantially within the sleeve whereby further tightening of the expansion element can occur without further substantial radial expansion of the sleeve, and the thread in the sleeve being such that when the sleeve is expanded into its set condition the thread assumes a substantially cylindrical form compatible with that of the cylindrical thread portion of the threaded shank.
15. A masonry anchor according to Claim 14, wherein the sleeve comprises an internal tapered thread which is engaged with the tapered thread portion of the shank prior to radial expansion of the sleeve.
16. A masonry anchor according to Claim 15, wherein the sleeve is slit by a plurality of slots extending generally axially from the inner end of the sleeve, with the slots initially being closed at the inner end of the sleeve and opening as the sleeve expands radially outwardly.
17. A masonry anchor according to Claim 16, wherein in the initial condition of the sleeve the internal surface of the sleeve is conical and transforms into a cylindrical surface by opening of the inner ends of the slots as the sleeve expands radially outwardly.
18. A masonry anchor according to any one of Claims 15 to 17, wherein the sleeve is produced with a cylindrical thread form compatible with that of the cylindrical thread portion of the threaded shank and the sleeve is then deformed to produce from the cylindrical thread form a tapered thread form capable of threaded engagement with the tapered thread of the threaded shank.
19. A masonry anchor according to Claim 14, wherein the tapered thread portion of the expansion element is followed by a further substantially cylindrical thread portion of smaller diameter than the first cylindrical thread portion, the sleeve being mounted on the further cylindrical thread portion and expanding as the expansion element is rotated to move the tapered thread portion into the sleeve in order to set the sleeve within the hole.
20. A masonry anchor according to Claim 19, wherein the sleeve comprises a plurality of separate, part-cylindrical segments displaceable radially at their inner and outer ends upon expansion of sleeve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AUPJ1681/88 | 1988-11-25 | ||
| AUPJ168188 | 1988-11-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2003820A1 true CA2003820A1 (en) | 1990-05-25 |
Family
ID=3773542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2003820 Abandoned CA2003820A1 (en) | 1988-11-25 | 1989-11-24 | Masonry anchors |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA2003820A1 (en) |
| WO (1) | WO1990006448A1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4344382A1 (en) * | 1993-12-24 | 1995-06-29 | Hilti Ag | Method for producing an expansion sleeve of an expansion anchor |
| DE19528808A1 (en) * | 1995-08-05 | 1997-02-06 | Hilti Ag | Expansion dowels |
| NZ534214A (en) * | 2004-07-20 | 2006-01-27 | Brl Patents Ltd | Structural connector with bolt assembly expanding sleeve portion which does not contact connected components |
| CN106402127A (en) * | 2016-10-27 | 2017-02-15 | 苏州市淞舜五金有限公司 | Special-shaped nut |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB323583A (en) * | 1928-10-20 | 1930-01-09 | John Joseph Rawlings | Improvements relating to tubular wall plugs |
| CH319871A (en) * | 1955-11-25 | 1957-03-15 | Reber Samuel | Method for fastening an object to a base, fastening produced according to this method, as well as wall dowels with expansion screws for carrying out this method |
| US3742809A (en) * | 1971-08-04 | 1973-07-03 | Expansion Bolt Co | Expansion anchor with conically tapered and threaded interacting parts |
| DE2454718A1 (en) * | 1974-11-19 | 1976-05-26 | Kenneth B Zifferer | Anchor bolt for floors or walls - has tapered bolt end fitting in threaded internal cone sleeve section |
| DK137690B (en) * | 1975-04-10 | 1978-04-17 | Torben Bredal | Anchor bolt. |
| ZA765270B (en) * | 1976-09-02 | 1977-10-26 | D Fermo | Improvements in expansion anchor devices |
| DE3116424A1 (en) * | 1981-04-24 | 1982-11-11 | Hilti AG, 9494 Schaan | DUEBEL |
-
1989
- 1989-11-24 CA CA 2003820 patent/CA2003820A1/en not_active Abandoned
- 1989-11-24 WO PCT/AU1989/000507 patent/WO1990006448A1/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| WO1990006448A1 (en) | 1990-06-14 |
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