AU600184B2 - Drive head apparatus for a rock boring machine - Google Patents

Description

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AUSTRALIA

Patents Act COM PLETE SPECIFICATION

(ORIGINAL)

u 4 Class Int. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority Related Art: Tis dor-amrent contains- the arnc-nd-il'nts made undcr, Section 4~9 and is corre. -t for I printing.

APPLICAiNT'S REYERENCE: P87-8873 Name(s) of Applicant(s): The Robbins Company Address(es) of Applicant(s): 650 S. Orcas Street, Seattle, Washington, UNITED STATES OF AMERICA.

Address for Service is: PHILLIPS ORMONDE FITZPATRICK Patent and Trade Mark Attorneys 367 Collins Street Melbourne 3000 AUSTRALIA Complete Specification for the invention entitled: DRIVE HEAD APPARA0IJS FOR A ROCK BJR~iG MACIMIN Our Ref 115079 POF Code: 43383/29636 The following statement is a full description of this invention, including the best method of performing it known to applicant(s): 6003q/1-1 1

TITLE

DRIVE HEAD APPARATUS FOR A ROCK BORING MACHINE This invention relates to drive head apparatus for driving the drill string of a rock boring machine.

oS o BACKGROUND OF THE INVENTION When driving a drill string in rock boring, it is highly 0o "2 desirable to have a floating and swivelling bearing for the drive o* connection, in order to absorb overturning forces transmitted by 0" o 0 the drill string during drilling, or to guard against any unforeseen loads that might occur during operation. However, the provision of such floating and swivelling bearings is expensive and, when worn, the bearings require expensive parts replacement.

This also applies to the spli-ed teeth used with such a bearing, which normally wear in the recoiled position of the bearing, so that the remainder of the length of the splinad teeth along the 0 Iaxial recoil slide path are usually still in good condition whilst those at the recoiled end are worn.

OBJECT OF THE INVENTION It is an object of this invention to provide drive head apparatus for a drill string of a boring machine that can alleviate these problems.

1A SUMMARY OF THE INVENTION In accordance with this invention there is provided drive head apparatus for a drill string of a boring machine, said apparatus comprising one or two drill string connectors securable to drive a drill string, the connector(s) being floatingly mounted in a housing to recoil in use against resilient means whilst being connected to driving splines, there being an axially fixed bearing surface behind each drill string connector limiting the recoil 1C movement, and each drill string connector having a co-opera.it floating bearing surface for engagement with the associated fixed S bearing surface, the floating bearing surface being replaceably secured to the associated drill string connector.

Preferably the drill string connector has an approximately uniform cross-sectional area arranged to achieve uniform temperature treatment throughout the connector.

Further preferably, in the case of a boring machine which is bi-directional, provision is made for a further drill string connector to be floatingly and swivellably mounted at an opposite side of the housing to the first drill string connector, with the resilient means mounted between the two drill string connectors, preferably being in the form of a coil spring. There is also provided for the further drill string connector to have said fixed and floating bearing surfaces.

Still further, provision is made for a splined tooth ring drive for the drill string connectors, which is replaceably seated 2 _I I_ in a ring body, and which is arranged to be reversible within its seating to have one axial end interchangeable with the other.

BRIEF DESCRIPTION OF THE'DRAWING A preferred embodiment of the invention is described below by way of example only, and with reference to the accompanying drawing in which FIG. 1 is a view partly in axial cross-section and partly in side elevation of a boring machine drive head apparai-us according to the invention.

o "o DETAILED DESCRIPTION OF THE DRAWINGS 9, As illustrated in FIG.l, a housing 1 is shown enclosing drive head apparatus, the drive head and its parts being symmetrical and concentric about a center axis 2, with one side 3 of the apparatus being shown in axial cross-section.

S',I In opposed axial relation, as shown in side 3, are drill string connectors 4 and 5 respectively, being the upper and lower drill string connectors for use in either drilling up or drilling down. These drill string connectors take the form of a box section of a threaded drill pipe, in order to receive the pin of drill pipe sections which are made up to form a drill string. Each connector is secured to an opposite end of a coil spring 6 so that recoil can occur with the formations sliding inwardly into the housing against the spring biasing.

The upper connector 4 has axial splines 7 around it which are relatively short in axial length, and located at the uppermost end.

3 A floating bearing 8 is located around the spring 6 at the inside end of the formation, with a spheroidal surface 9 for contacting the spheroidal surface 10 of the axially stationary bearing body 11.

The lower drill string connector 5 has a radial flange 13 at its innermost end, and between the flange and the wall of the boxlike connecting formation is located bearing 16 with a spheroidal bearing surface 14, which is faced downwardly and is shown riding against a like fixed spheroidal bearing surface 15 secured to the housing 1.

iEach of the spheroidal bearings 8 and 16, which are secured oO to the drill string connectors 4 and 5, are of aluminum bronze, and are replaceably secured therein, In the case of the upper bearing 0 S4 insert 8, the insert is suitably secured as by bolt means (not shown), whereas the lower insert 16 can be glued into position °o since it will only incur a downward force which will be taken up by the annular flange 13.

0 4 In use, the spheroidal bearing surfaces 9, 10, 14 and 15, if properly greased and kept dirt free should not be wear parts but 0 a cd should there be wearing the inserts 8 and 16 can be removed and replaced without the necessity for replacing an expensive drill string connector with treated bearing surfaces, or replacing the bearing body 11, which is an expensive casting. The bearing body 11 can thus be made of a suitably hard material with the intention that the inserts 8 and 16 will wear if any wearing is to take place.

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The provision of the bearing surfaces as replaceable parts allows the drill string connectors 4 and 5 to have approximately uniform cross-sectional dimensions. This in turn allows for a uniform heat treatment throughout the connectors.

Splined drive ring 17, by which the splines 7 of the drill string connector 4 are driven, is axially slidable out of it seating and is connected therein by means of a splined connection 18 so that if wear at the upper position of the splines 7 occurs, the splined ring 17 can be axially reversed. Also, should the 1 splined ring 17 ultimately wear out it can be replaced without the necessity of replacement of the body 11. Similar replaceable gear rings (not shown) can also be supplied for the lower drill string connector 0 00 o oo 9 00 0 0 V 0 w <S

Claims (10)

1. Drive head apparatus for a drill string of a boring machine, said apparatus comprising a drill string connector securable to drive a drill string, said connector being floatingly mounted in a housing to recoil in use against resilient means whilst being connected to driving splines, there being an axially fixed bearing surface behind the drill string connector having a co-operant floating bearing surface for engagement with the fixed bearing surface, the floating bearing surface being replaceably secured to the drill string connector.

2. Apparatus as claimed in Claim 1, in which the drill string connector has an approximately uniform cross-sectional area 5,1" arranged to achieve uniform temperature treatment throughout the connector.

3. Apparatus as claimed in Claim 2, arranged for use with a bi-directional boring machine and including a further drill string connector floatingly and swivellably mounted at an opposite side of the housing to the first drill string connector, with the resilient means arranged therebetween.

4. Apparatus as in Claim 3, wherein said resilient means is in the form of a coil spring.

Apparatus as claimed in Claim 1, arranged for use with a bi-directional boring machine and including a further drill string connector floatingly and swivellably mounted at an opposite side 6 F- I "41f of the housing to the first drill string connector, with the resilient means arranged therebetween.

6. Apparatus as in Claim 5, wherein said resilient means is in the form of a coil spring.

Apparatus as claimed in Claim 1, further comprising a splined tooth ring drive for the drill string connector and a ring body in which the ring drive is replaceably seated, said ring drive being reversible in its seat to have one axial end interchangeable with the other.

8. Apparatus as claimed in Claim 3, further comprising a splired tooth ring drive means for one of the drill string connectors and a ring body in which the ring drive is replaceably seated, said ring drive being reversible in its E£at to have one axial end interchangeable with the other.

9. Apparatus as claimed in Claim 5, further comprising a splined tooth ring drive for a drill string connector and a ring Sbody in which the ring drive is replaceably seated, said ring drive Sbeing reversible in its seat to have one axial end interchangeable with the other.

10. Apparatus as claimed in Claim 6, further comprising a splined tooth ring drive for a drill string connector and a ring body in which the ring drive is replaceably seated, said ring drive being reversible in its seat to have one axial end interchangeable with the other. DATED: 25 November, 1988 PHILLIPS ORMONDE FITZPATRICK Attorneys for: THE ROBBINS COMPAY A j 7