AU702076B3

AU702076B3 - Wear studs

Info

Publication number: AU702076B3
Application number: AU68079/98A
Authority: AU
Inventors: Anton Fowler
Original assignee: Avt Anti Verschleiss Technik GmbH
Current assignee: AVT ANTI-VERSCHLEISS-TECHNIK GmbH
Priority date: 1998-05-22
Filing date: 1998-05-22
Publication date: 1999-02-11
Anticipated expiration: 2004-05-22

Description

3 According to a first aspect of this invention there is provided a wear stud for mounting on a wear surface of a wear member, the wear stud including: a hard metal insert having wear resistant properties, and an attachment element of weldable steel defining a receptacle within which the hard metal insert is snugle received, the attachment element having a base, the size of which is such that the attachment element can be welded to a wear surface by passing current through the attachment element and into the wear surface in a single welding step.

Preferably the attachment element is substantially circular-cylindrical and the receptacle is also substantially circular-cylindrical being sized to receive the insert with 10 a tight friction fit, and the attachment element also includes a flux element on the base thereof o Advantageously the hard metal insert is made of tungsten carbide, the attachment element is made of a weldable steel alloy having a hardness of 50-60 HRC, the flux 15 element is made of aluminium, and the hard metal insert is soldered to the attachment •elem ent.

According to another aspect of this invention there is provided a method of mounting a wear stud on a wear member having a wear surface, the method including: providing a wear stud comprising a hard metal insert received within an attachment element of weldable steel; and welding the attachment element onto the wear surface of the wear member to provide a wear stud having a hard metal insert securely and firmly mounted onto the wear surface.

Preferably the attachment element is welded directly onto thdie wear surface.

a metal strip corresponding to a helical line of the wear studs can be used to weld the wear studs onto the wear surface.

Optionally the wear studs can be mounted on the strip and the strip can then be welded onto the wear surface. Alternatively the strip can be mounted on the wear surface and then the wear studs can be welded onto the strip.

Preferably the attachment element is substantially circular-cylindrical and defines a substantially circular-cylindrical receptacle and the hard metal insert is received in the receptacle with a snug press-fit, and the attachment element has a flux element on its base.

A method of mounting a wear stud to a wear member in accordance with this invention may manifest itself in a variety of forms. It will be convenient to hereinafter describe in detail one preferred embodiment of the invention with reference to the 15 accompanying drawings. It is to be clearly understood however that the specific nature of this description does not supercede the generality of the preceding broad description. In the drawings: FIG. 1 is a side elevation of a backreamer having many wear studs mounted thereon in accordance with the invention; 20 FIG. 2 is a cross sectional side view of a wear stud prior to commencing attachment of the stud to a backreamer; FIG. 3 is a cross sectional side view of a wear stud mounted onto the wear surface of a backreamer in accordance with the invention; and FIG. 4 is a cross sectional side view of the wear stud of FIG. 3 after a 25 reasonable amount ofuse.

25 reasonable amount of use.

In FIG. 1 reference numeral 1 refers generally to a backreamer.

The backreamer 1 comprises a broadly cylindrical member 2 having a wear surface 3 with a plurality of wear studs 4 mounted on the wear surface 3. The wear studs 4 are arranged in lines with a spiral configuration.

The wear studs 4 comprise a hard metal insert 5 received within an attachment element 6 having a short circular cylindrical pot-like configuration. As shown in FIG. 2, the inserts 5 is tightly received in a receptacle 7 defined in the attachment element 6.

Typically the insert 5 is soldered to the element 6 to enhance its attachment to the element 6. On the base of the element 6 is a flux element which is an ignition point in the form of a ball 10 made of aluminium.

The hard metal insert 5 is made of tungsten carbide and is an exceptionally hard material which makes the insert capable of performing its rugged task. The attachment element 6 is made of weldable steel having a hardness of 50-60 HRC.

o In the manufacture of the wear stud, the element 6 is formed in a first step with the receptacle 7 for the hard metal insert, and a further receptacle for receiving a flux element. The element 6 is then heat treated at 1000 0 C to increase its hardness. The hard metal insert 5 is pressed with some effort into the receptacle 7 where it is received with a tight fit. Once in the receptacle, the insert 5 is soldered to the element 6 at about 600 0 C. The aluminium flux element 10 is then mounted on the base of the element 6.

S. The attachment of the wear stud 4 to the surface 3 is shown clearly in FIG. 3.

The attachment element 6 is mounted directly onto the wear surface 3 of the backreamer 1 by means of a welding step, eg carried out with an electrically powered hand held welding gun. Typically a light portable welding gun is used. A 6 circumferential ferrule is mounted over the chuck of the welding gun such that the ferrule extends around the element 6. The ferrule retains energy within the weld zone and also keeps out oxygen. The flux reacts with impurities and oxygen in the weld zone and thus assists the welding process.

FIG. 4 shows the wear stud 4 after some considerable use.

An advantage of the wear stud described above with reference to the drawings is that it can be quickly and efficiently attached to the wear surface of a backreamer during manufacture of the backreamer. No drilling or treatment of the surface of the backreamer is required. Further it also enables the quick and efficient replacement of worn wear studs with new wear studs. Essentially the worn wear studs are simply removed from the wear surface and fresh wear studs are welded thereon.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as is herein defined in the appended claims.

S

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS: 1. A wear stud for mounting on a wear surface of a wear member, the wear stud including: a hard metal insert having wear resistant properties, and an attachment element of weldable steel defining a receptacle within which the hard metal insert is snugle received, the attachment element having a base, the size of which is such that the attachment element can be welded to a wear surface by passing current through the attachment element and into the wear surface in a single welding step.

2. A wear stud according to claim 1, wherein the attachment element is substantially circular-cylindrical and the receptacle is also substantially circularcylindrical and the hard metal insert is soldered to the attachment element.

S• 3. A wear stud according to claim 1 or claim 2, wherein the hard metal insert is made of tungsten carbide, the attachment element is made of a weldable steel alloy having a hardness of 50-60 HRC and the flux element is made of aluminium.

DATED THIS Sixth DAY OF November 1998.

AVT ANTI-VERSCHLEISS-TECHNIK-GMBH

BY

PIZZEYS PATENT AND TRADE MARK ATTORNEYS