AU626211B2

AU626211B2 - Balustrade post structure

Info

Publication number: AU626211B2
Application number: AU33083/89A
Authority: AU
Inventors: David Thomas Doyle; Neil William Dunne
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-18
Filing date: 1989-04-17
Publication date: 1992-07-23
Anticipated expiration: 2009-04-17
Also published as: AU3308389A

Description

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 Form COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE 626211 Short Title: Int. Cl: Application Number: -PI 7806 Lodged: 18 April 1988 Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: tf Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: G M-BASTRABING-PTY- South Wal eS-OQr- us-ealia DAVID THOMAS DOYLE of 39/4-14 Watson Street, Neutral Bay, New South Wales, Australia and NEIL WILLIAM DUNNE of Unit 5/19-23 Cairo Street, Cammeray, 2062, New South Wales, Australia GRIFFITH HACK CO.

71 YORK STREET SYDNEY NSW 2000

AUSTRALIA

S0068 15 17/04/e9 Complete Specification for the invention entitled: BALUSTRADE POST STRUCTURE The following statement is a full description of this invention, including the best method of performing it known to me/us:- 9992A/MS g :I 'I

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r n; 1 i, 2 This invention relates to a balustrade post structure which is used to form a balustrade around verandahs, balconies, bridges, stairwells, rooftops and the like and to the balustrade so formed.

Balustrade units comprising at least an upper and lower bar interconnected by balusters for installation around verandahs, balconies, stairwells and the like are well known and have been fabricated from many conventional materials such as iron, steel, wood, aluminium and synthetic plastics material by conventional forming techniques such as welding, grilling, casting and similar techniques. Conventional constructions have suffered from the disadvantage that in order to provide safe, strong and easily maintainable structures, the finished product is often unattractive, bulky, and costly. AU 477021 discloses one type of balustrade post structure which comprises a double wedge system which while overcoming many existing disadvantages requires much thicker wall sections in order to achieve required safety standards. While it may be convenient to have off-site fabrication of the cr..ponent parts, it is desirable that there is suffici nt flexibility if needed so that final adjustments can be done on site. These may include using a laser leveller to adjust to the required level. Another balustrade post structure consists of a base plate having an integral spigot standing up from the base plate and which is an interference fit inside the end of the post. The base and posts are factory assembled in a hydraulic press.

New and more useful alternatives to the structures described above are provided by the present invention which obviate or minimise the foregoing disadvantages in a simple yet effective manner or at least provide the public with a useful choice.

In a first aspect, the present invention provides a balustrade post structure adapted to be secured to a substrate, the post structure comprising an extruded post element and a base plate, the base plate being adapted to C C C CI c c 20701A438/30.4.92 I ~B

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;i 3 be bolted to the substate and one end of the post element being adapted to be supported on the base plate, the extruded post element having a wall surface forming a hollow interior and the wall surface incorporating a series of spaced elongated cavities of uniform cross section extending parallel to a central axis of the post element and spaced around the axis, each of said cavities being formed with a small gap facing towards the centre of the post structure and at least one slot in the wall of the cavity, and each cavity being tapped with a screw threading extending along the cavity from the end of the post element which is to be supported on the base plate, the gap and the slot being arranged such that during tapping of the thread by a tap, the gap is sized to enable cut particles to be removed from the cavity and the slot is sized to equalise the pressure on the tap to maintain alignment of the tap in the cavity, and the base plate having a series of apertures therethrough corresponding to the cavities for receiving screws having a thread corresponding to that cut in the cavities whereby the post element can be anchored to the base plate by a series of these screws.

In a second aspect, the present invention relates to a method of forming such structures. The method S 25 comprises forming a balustrade post structure comprising taking an extruded post element having a hollow interior and an external wall extendiny around a central axis, the external wall having a series of elongated cavities of S: uniform cross section integrally formed therewith and extending on the interior thereof parallel to said central axis, the cavities each having a relatively small diameter compared with the distance across the post element, and each cavity being formed with a small gap facing towards the centre of the post structure and at least one slot in the wall of the cavity using a tap to cut a screw thread from one end of the post structure i along each cavity, each screw thread extending along the 7A 20701 A1438/30.4.92 i 3A respective cavity a substantial distance as compared to the diameter of the cavity, wherein the small gap enables cut particles to be removed from the cavity and the slot equalises the pressure on the tap to maintain alignment of the tap in the cavity, assembling a base plate against the end of the post element and inserting the fixing screws through apertures in the base plate to engage correspondingly in the tappei. cavities whereby the base plate and post element are secured together to provide a post unit, the post unit being adapted to be rigidly mounted onto a building structure by a bolt adapted to pass from the interior of the post element and through the base plate into a receiving threaded anchoring unit in the building structure.

20701A/438/30.4.92 N: L n; cn~ 4- The components of the balustrade post structure are preferably formed of extruded aluminium, However, any other suitable material could be used.

In a preferred embodiment, the extruded aluminium has at least four inside corners with one of the cavities in each corner.

Viewed in cross section, each cavity preferably has five sides of a hexagon. One advantage of the opening left by missing sixth side of the hexagon is that the swarf provided by the tool used to cut the thread of the cavities easily falls away.

Preferably, the tool used for cutting the thread of the cavities is a spiral fluted tap. The advantage of using such an tool, which has a number of spiral cuts around its axis, is that it permits cutting of the screw thread even though there is an opening along one side of each cavity.

Surprisingly the invention permits the use of a thin walled aluminium section post which achieves a strength well in excess of the AS 1170 Loading Code Category (1,2,3 or 4) Terrain.

This invention will be more fully understood from the following description of a preferred embodiment of a balustrade post structure which can be connected to spaced newel posts to form a hand railing around balconies, verandahs, etc. The description is given with reference to the accompanying drawings wherein: Fig 1 is an exploded view illustrating an embodiment of the invention; Fig 2 is an end view of the post shown in Fig 1; Fig 3 is a detailed view of a corner of the post as shown in Fig 2; Fig 4 is a plan view of the base plate of the structure shown in Fig 1; Fig 5 is a front elevation of the base plate of Fig 4; and TTR 4 Fig 6 is a side elevation of the base plate of Fig 4.

0 0 20701AI428/20.11.91 V As illustrated, a balustrade post unit is disclosed which comprises an extruded aluminium post 10 arranged to be supported on a base plate 11. The base plate 11 is adapted to be secured to a substrate 14.

The post 10 is square and has a smooth exterior profile with rounded corners 15 and relatively thin, flat side walls 15a. At each corner, the post 10 has an internal cavity 16 which is defined by a pair of inwardly directed ribs 17. Each of the cavities 16 is generally hexagonally in cross-section with one side open. At the juncture of each of the other five sides there is provided a small V-shaped slot 19.

The base plate 11 is a solid rectangular block including a series of countersunk bores 18 and a central oval slot 21.

Although not shown, the cavity 16 is tapped from the base end of the post a distance of about half the exterior distance across the post 10. Furthermore, the diameter of the tapped cavity 16 is about one tenth the distance across the post 10. In the embodiment shown the distance across the post 10 is in the order of 5cm and the thread in each cavity extends 2cm from the base end o° of the post.

c a The tapping operating is performed using an elongated S0: 25 tap having at least one spiral relief cavity or flute E "O extending along the tap for removal of the cut particles.

The balustrade post unit is secured together as 0 follows. The post 10 is mounted to the base plate 11 by means of four stainless steel screws 12 which are 30 inserted through the bores 18 and secured into the corresponding screw threaded cavity 16 in the post The assembly is placed over the substrate 14 and anchored by a bolt 13 inserted down the post and through the oval slot 21 in the base, wherein it is secured to an expanding anchor 20 located in the substrate by tightening with a spanner.

Embodiments of this invention can employ a thinned wall aluminium section post and the assembled balustrade 20701A/438/30.4.92 j i

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6 unit surprisingly has the strength well in excess of ASA 1170 loading code category (1,2,3 or 4) terrain.

Furthermore, the embodiments can be economical to produce and do not need any special equipment at site for installation.

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Claims

1. A balustrade post structure adapted to be secured to a substrate, the post structure comprising an extruded post element and a base plate, the base plate being adapted to be bolted to the substate and one end of the post element being adapted to be supported on the base plate, the extruded post element having a wall surface forming a hollow interior and the wall surface incorporating a series of spaced elongated cavities of uniform cross section extending parallel to a central axis of the post element and spaced around the axis, each of said cavities being formed with a small gap facing towards the centre of the post structure and at least one slot in the wall of the cavity, and each cavity being tapped with a screw threading extending along the cavity from the end of the post element which is to be supported on the base plate, the gap and the slot being arranged such that during tapping of the thread by a tap, the gap J is sized to enable cut particles to be removed from the cavity and the slot is sized to equalise the pressure on the tap to maintain alignment of the tap in the cavity, and the base plate having a series of apertures therethrough corresponding to the cavities for receiving screws having a thread corresponding to that cut in the cavities whereby the post element can be anchored to the base plate by a series of these screws.

2. A post structure as claimed in claim 1, wherein the threading tapped in each of the cavities extends therealong by a distance of about half the exterior distance across the post element.

3. A post structure as claimed in claim 1 or claim 2, wherein the tapped cavities each have a diameter of about one tenth the distance across the post element. C~jC, 20701A/438/30.4.92 8

4. A post structure as claimed in any one of the preceding claims wherein the distance across the post structure is of the order of 5cm and the screw threading in each of the cavities extends at least 2cm therealong and the threading is a fine machine threading.

A post structure as claimed in any one of the preceding claim wherein the series of cavities comprises at least four cavities substantially uniformly spaced around the axis of the post element.

6. A post structure as claimed in any one of the preceding claims wherein the post element has a smooth exterior profile and each of the cavities is formed by two interior formations in the extrusion with the small gap facing towards the centre of the post element, and being located between the formations, and wherein prior to threading, each cavity has a substantially hexagonal cross sectional shape.

7. A post structure as claimed in claim 6 wherein one of the 6 sides of the hexagonal cross sectional shape of 20 each of the cavities is left open to form said small gap.

8. A method of forming a balustrade post structure as claimed in any one of the preceding claims and comprising taking an extruded post element having a hollow interior and an external wall extending around a central axis, the external wall having a series of elongated cavities of uniform cross section integrally formed therewith and extending on the interior thereof parallel to said central axis, the cavities each having a relatively small diameter compared with the distance across the post element, and each cavity being formed with a small gap facing towards the centre of the post structure and at least one slot in the wall of the cavity, using a tap to cut a screw thread from one end of the post structure along each cavity, each screw thread extending along the Ii I 11 20701A/438/30.4.92 9 respective cavity a substantial distance as compared to the diameter of the cavity, wherein the small gap enables cut particles to be removed from the cavity and the slot equalises the pressure on the tap to maintain alignment of the tap in the cavity, assembling a base plate against the end of the post element and inserting the fixing screws through apertures in the base plate to engage correspondingly in the tapped cavities whereby the base plate and post element are secured together to provide a post unit, the post unit being adapted to be rigidly mounted onto a building structure by a bolt adapted to pass from the interior of the post element and through the base plate into a receiving threaded anchoring unit in the building structure.

9. A method as claimed in claim 8 wherein the tapping operation is conducted using an elongated tap having at least one spiral relief cavity or flute extending along the tap for the removal of cut metal particles.

A method as claimed in either claim 8 or 9 and wherein the post element and the base plate are of o aluminium and the fixing screws are of stainless steel.

11. A balustrade post structure substantially as S described herein with reference to the accompanying drawings. 25

12. A method of forming a balustrade post structure osubstantially as herein described with reference to the accompanying drawings. aaaa Oaa, DATED this 24th day of March 1992 D D ALUMINIUM BALUSTRADING PTY. LTD. By their Patent Attorneys GRIFFITH HACK CO 2 3 2070 1 A438/30.4.92