AU2001100201A4 - Masonry anchors - Google Patents

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT

(ORIGINAL)

NAME OF APPLICANT(S): ACTUAL INVENTOR(S): ADDRESS FOR SERVICE: INVENTION TITLE: RAMSET FASTENERS (AUST.) PTY.LIMITED DAVIES COLLISON CAVE, Patent Attorneys 1 Little Collins Street, Melbourne, 3000 "Masonry anchors" The following statement is a full description of this invention, including the best method of performing it known to us: P:\OPER\RSH\p4847-99 pt 349.doc-14 Deober, -2- MASONRY ANCHORS The present invention relates to masonry anchors and more particularly to a masonry anchor of expansion type.

Masonry anchors of expansion type conventionally comprise a cylindrical expansion sleeve formed of metal. The sleeve is mounted over the shank of a bolt having at its forward or inner end a conical element of external diameter greater than the internal diameter of the sleeve. In use, the anchor is placed into a cylindrical cavity drilled into masonry and the conical element is drawn into the inner end portion of the sleeve by tightening the bolt. This action causes the inner end portion of the sleeve to expand outwardly into tight anchoring engagement with the cylindrical wall of the hole.

Masonry anchors of the above type are described in detail in our prior Australian 15 patents Nos. 559285 and 697330. Each of these prior anchors features an expansion sleeve which is configured to contract axially during tightening of the bolt. The axial contraction of the expansion sleeve is termed "pull-down". The pull-down capability is introduced into S the sleeve to enable a gap to be taken up between an object being clamped and the surface of the masonry as may exist if a component with a slight bow is being clamped and it also 20 enables final tightening of the anchor to be translated into a high compression or clamping force between the component and the surface of the masonry, this latter feature being of significance when the component is subjected to cyclic loading.

Usually the conical expansion element is integrally formed with the shank of the bolt at its inner end, the outer end of the shank carrying a nut which is tightened against the external surface of the component in order to set the expansion anchor and clamp the component. For certain applications the nut is replaced by a so-called post-head which comprises an internally-threaded sleeve engaged with the shank of the bolt and having at its outer end a countersunk driving head which lies within a countersunk hole in the surface of the component. This is used in situations where an exposed nut and associated portion of the bolt shank projecting from the external surface of the component is unsuitable, for example due to aesthetic considerations. This form of expansion anchor is P:\OPER\RSH\pqJ847-99 pi 349.doc-l4 December, 24() -3known as a post-head anchor. However due to the presence of the countersunk head which effectively closes the outer end of the threaded sleeve the threaded sleeve is capable of only limited axial movement along the shank of the bolt and when the expansion sleeve has provision for axial pull-down the limited extent of the axial movement of the post-head along the shank may be insufficient to achieve the required degree of pull-down.

According to the present invention, there is provided a masonry anchor of expansion type comprising a threaded shank and an expanding sleeve, the expansion sleeve having facility for axial contraction after setting the anchor in order to provide a pull-down effect, the shank being threaded at its inner end portion to receive an internally-threaded expansion element which is driven into the inner end portion of the expansion sleeve upon setting of the anchor, and the shank having at its outer end portion an integrally formed post-head comprising an axially-extending sleeve portion having an outer diameter corresponding to the outer diameter of the expansion sleeve and a head portion at the outer 15 end of the sleeve portion.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:- Figure 1 is an exploded view showing the components of a post-head expansion anchor in accordance with a preferred embodiment of the invention; Figure 2 is a view showing the anchor in its assembled state; and S.i Figure 3 is a side view, partly in section, corresponding to Figure 2.

9*9999 As shown in the accompanying drawings an expansion anchor comprises a shank 2 25 carrying an expansion sleeve 4. The sleeve is capable of axial contraction to provide a pull-down effect and may feature the characteristics described in our earlier patents as aforesaid or may be of other suitable form to provide the required effect. At its outer end portion the shank 2 carries a post-head consisting of a sleeve-like portion 6 of an outer diameter substantially corresponding to the outer diameter of the expansion sleeve 4 and a countersunk head portion 8 slotted in its outer face (not shown) to receive a suitable driver.

P:\OPER\RSH\pq4847-99 pet 349.doc-14 Dcnmber, 2100 -4- However in contrast to previous forms of post-head anchor, the sleeve-like portion 6 is not threadedly mounted on the shank 2 but is instead formed integrally with the shank 2. The bolt shank 2 is threaded at its inner end portion to receive the conical expansion element 10 which is internally threaded and is drawn into the interior of the expansion sleeve 4 by movement along the threaded shank when the anchor is tightened. As a result of this configuration when the anchor is set within the hole by expansion of the expansion sleeve 4, further tightening will cause the integral post-head and shank to displace inwardly with the inwards displacement being accommodated by axial collapse of the expansion sleeve 4 due to the abutting engagement between the inner axial end edge of the sleeve-like portion 6 of the head with the outer axial end edge of the expansion sleeve 4 as the threaded part of the shank 2 travels downwardly or inwardly relative to the internallythreaded expansion cone. It will be understood that the necessary thread length needed to achieve full setting and maximum pull-down (determined by the maximum permissible axial contraction of the expansion sleeve) is unaffected by the presence of the post-head.

The embodiment has been described by way of example only and modifications are possible within the scope of the invention.

Throughout this specification and claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers or steps but not the exclusion of any other integer or group of integers.

The reference to any prior art in this specification is not, and should not be taken 25 as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (1)

1. A masonry anchor of expansion type comprising a threaded shank and an expanding sleeve, the expansion sleeve having facility for axial contraction after setting the anchor in order to provide a pull-down effect, the shank being threaded at its inner end portion to receive an internally-threaded expansion element which is driven into the inner end portion of the expansion sleeve upon setting of the anchor, and the shank having at its outer end portion an integrally formed post-head comprising an axially-extending sleeve portion having an outer diameter corresponding to the outer diameter of the expansion sleeve and a head portion at the outer end of the sleeve portion. DATED this 14 th day of December, 2000 RAMSET FASTENERS (AUST.) PTY.LIMITED i By its Patent Attorneys: *i DAVIES COLLISON CAVE 0* 00 0