AU594885B2 - Rotary roller reamer - Google Patents

Description

11 594885 Form COMMONWEALfH OF AUSTRALIA PATENTS ACT 1952-62 COMPLE1TE SPECIFICATION

(ORIGINAL'

FOR OFFICE UOSE: Application Number,: L odg ed: Class Int. Class CTap~e Specification Lodged: Accepted: Published: Re4ate96 Art:, L pATENT, TRADE MARKS 30 JUN 1988 VUjji &UST9ALlA NaW ~of Applicant: Address of Applicont:, Aseual-l nventcr! 0 .0 Address for Service: TO BE COMPLETED BY APPLICANT GEARHART UNITED PTY. LTD.

110 Francis Road, Wingf ield, State of South Australia, Comnmonwealth of Australia JOHN FRANCIS KENNEDY Care of R.K. MADDERN ASSOCIATES, 345 King William Street, Adelaide, State of South Australia, Commonwealth of Australia j Complete Specification for the invention' entitled: "ROTARY ROLLER REAMER" The following statement is a full description of this invention, including the best method of performing It known to im. LS AOOO 1 Z7 E%00 17 3/06/88 11 1'1V?-11V--1-3111 -1 0 .1 1 I This invention relates to a reamer of the rotary roller type which is utilised to locally compact the soil of a wall which defines a borehole in the earth.

Boreholes are normally bored with boring bits on the ends of drill rods, and the hole defining surfaces are subsequently stabilised by means of rotary roller reamers in order to locally compact the earth which might otherwise remain loose and could partly collapse into the hole.

The borehole reamers which are generally used employ reamer bodies which are generally cylindrical and rotatable about longitudinal cylindrical axes, each body having recesses which extend inwardly from the body outer surface, and those recesses contain freely rotatable reamer rollers, each reamer body being rotatable over a fixed spindle, and having a plurality of hard bullnosed projections projecting outwardly from it, the bullnosed projections usually being of tungsten carbide or other material much harder than steel from which the reamer rollers are made.

Some difficulties are encountered in the maintenance of such arrangements, in that quite often damage is imparted to the retention means which retain the reamer rollexs in place, due to the tendency for earth to firmly compact hetween the roller which should be rotatin and the reamer body. A second problem is also encountered in that the reamer body is excessively long, since the 2 pins about which respective rollers rotate are driven in a longitudinal direction through apertures in the reamer body and the clearance apertures in the respective reamer rollers, and these pins to be so located require the existence of longitudinally extending access slots.

A still further problem which is encountered is that the very expensive hard tungsten carbide projections are only partly worn when the apertures in the iollers and the pin surfaces are severely worn: and therefore the reamer rollers constitute a high cost component.

s.* With the object of substantially reducing the above- 00s mentioned difficulties, in this invention a rotary roller reamer comprises a reamer body having a plurality of circumferentially spaced recesses extending radially inwardly from an outer surface of the body, each recess having a central portion and two end portions, respective *ean blocks in the recess end portions, retention means releasably retaining each block in its said recess end portion, rollers in respective recess central portions, 30. each roller having hard inserts projecting therefrom, and spindle and bearing assemblies co-operable between the ends of each roller and their adjacent blocks.

With this invention, the retention means can comprise wedge blocks, and the removal of the wedge blocks can be easily effected if use is made of locking screws which bear against the blocks both when screwed into or screwed out of the body, so that the removal 3 or replacement of the reamer rollers is greatly simplified. If use is additionally made of sealing rings (for example O-rings) around the projecting spindle ends of the rollers, the bearing life can be extended to be at least that which is required for the effective life of the tungsten carbide projections.

An embodiment of the invention is described hereunder some detail with reference to and is illustrated in the accompanying drawings in which; :.0 Fig. 1 is a fragmentary side elevation of a reamer, showing a roller containing tungsten carbide projections and bearing blocks retained to the reamer body by wedge blocks, Fig. 2 is a cross-section taken on line 2-2 of Fig.

Fig. 3 is a longitudinal section through portion of a reamer and also through the roller and bearing assembly, and Fig. 4 is a section taken on line 4-4 of Fig. 3, e In this embodiment, a rotary roller reamer comprises a reamer body 10 which has within it a central aperture 11, and three radially outwardly facing recesses 12 which are equally spaced circumferentially about the cutor surface of the body 10, each recess 12 having a central portion 13 which provides clearance for rotation of reamer rollers 14, and two end portions 15 each containing end blocks 16.

4- LL -LB l.r I 1 Each end block 16 is a bearing block, containing a respective bush 17 within which is rotatable an end spindle 18 of a roller 14, each roller 14 having two end spindles 18. In order to increase the life of the bearing 17, each bearing 17 is flanked at each end by a resilient O-ring 19 and 20 respectively (Fig. the 0rings functioning to inhibit entry of particulate material. The roller 14 has a plurality of apertures within whiuh short bull-nosed tungsten carbide inserts 21 :10. are retained by press fits, each tungsten carbide insert 21 having a bull-nosed projection portion for the o 1. compression of the particles of soil which define a borehole.

As said above, one of the main difficulties •15. encountered with prior art reamer rollers is that they cease to be functional after some use and maintenance costs are very high, partly due to the difficulty of removing the pin over which the rollers rotate. However in this invention, each bearing block 16 is provided 0. with one wedge face 24, and is retained in its respective recess end portion 15 by a wedge block 25 which is j clamped to the body 10 by means of clamping screws 26.

Each screw 26 has a head 27 which is movable within a recess 28 but confined by end walls of that recess so that if the screws are screwed inwardly they draw the block inwardly and if they are screwed outwardly, they effect a withdrawal of the block. The slope is 1 in 5 i j S- 16, or about 3 this being a standard Morse taper angle such that the tendency of the bearing blocks 16 to work loose is minimal while the ability to remove the wedge blocks 25 is maintained, It is believed that the life of the bearings 17 should be sufficient to enable full use to be made of the hard tungsten carbide inserts 21. This is very economical, since in many instances under prior art usage the rollers 14 are discarded when the tungsten carbide inserts are less than half way through their effective life. The cost can be much less than with prior art roller reamers because of the shorter length of the body 10, and the maintenance costs are also much less.

In the above embodiment the spindles 18 are described as extending from the rollers 14, but alternatively they can extend into the rollers 14 from the end blocks 16.

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Claims (4)

1. A rotary roller reamer comprising a reamer body having a plurality of circumferentially spaced recesses extending radially inwardly from an outer surface of the body, each recess having a central portion and two end portions, respective end blocks in the recess end portions, retention means releasably retaining each block in its said recess end portion, -llers in respective recess central portions, each roller having hard inserts projecting therefrom, and spindle and bearing assemblies co-operable between the ends of aach roller and their adiacent blocks. .0 2. A rotary roller reamer according to claim 1 wherein each said spindle and bearing assembly comprises a spindle projecting from an end of a said roller rotational in a bush in a said end block.

3. A rotary roller reamer according to claim 2 further comprising a pair of spaced resilient seals at the ends of each said spindle arranged to inhibit entry of particulate material into the bush in which that spindle is rotational.

4. A rotary roller reamer according to any preceding claim wherein each said end block comprises a wedge face, and further comprising a respective wedge block bearing against that face, and threaded fasteners securing the wedge block to the reamer body. 7 t A rotary roller reamer according to claim 4 wherein each said threaded fastener is a threaded screw having a head, its wedge block having a recess containing that head between recess end walls in such a way that rotation of the screw in one direction causes clamping movement of the wedge block, and in a reverse direction causes release movement thereof.

6. A rotary roller reamer substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings DATED this 30th day of June, 1988. GEARHART UNITED PTY. LTD. By its Patent Attorneys, S' R.K. MADDERN ASSOCIATES. .0 M 0 OO -8