U.S. patent application number 10/508246 was filed with the patent office on 2006-11-09 for grease filling arrangement in a cutter for a boring head.
This patent application is currently assigned to ATLAS COPCO SECOROC AB. Invention is credited to Lars Holmgren, Jonas Thuresson.
Application Number | 20060249311 10/508246 |
Document ID | / |
Family ID | 20287355 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060249311 |
Kind Code |
A1 |
Thuresson; Jonas ; et
al. |
November 9, 2006 |
Grease filling arrangement in a cutter for a boring head
Abstract
An arrangement for replenishing lubricating grease in drill
cutters (3) that include a conical outer barrel (7) which is
rotatable about a shaft (5) disposed centrally in the cutter,
wherein there is provided in the cutter shaft (5) a passageway (16)
that extends along the shaft from the cutter end of largest
diameter and that connects with a transverse passageway (18) which
opens into a bearing-accommodating space (13) in the cutter for
delivering lubricating grease to the space (13), and wherein a
lubricating nipple (19) is provided on the cutter end wall of
largest diameter and functions to allow lubricating grease to be
released from the bearing-accommodating space (13).
Inventors: |
Thuresson; Jonas; (Fagersta,
SE) ; Holmgren; Lars; (Sala, SE) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
ATLAS COPCO SECOROC AB
Fagersta
SE
|
Family ID: |
20287355 |
Appl. No.: |
10/508246 |
Filed: |
March 14, 2003 |
PCT Filed: |
March 14, 2003 |
PCT NO: |
PCT/SE03/00433 |
371 Date: |
May 10, 2005 |
Current U.S.
Class: |
175/228 |
Current CPC
Class: |
E21B 10/24 20130101 |
Class at
Publication: |
175/228 |
International
Class: |
E21B 10/24 20060101
E21B010/24 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 2002 |
SE |
0200875-3 |
Claims
1. An arrangement for replenishing lubricating grease in drill
cutters (3) that include a conical outer barrel (7) which cutter is
rotatable about a shaft (5) disposed centrally in the cutter,
characterised by a filling lubricating nipple (19) provided in the
cutter shaft (5) on the cutter end wall of largest diameter and
opening into a passageway (16) that extends longitudinally in the
cutter shaft (5) and that connects with a transverse passageway
(18) which opens out into a bearing-accommodating space (13) in
said cutter (3), for delivering lubricating grease to said
bearing-accommodating space (13) at a position beyond the innermost
bearing (9) of bearings (9, 10) disposed between the outer barrel
(7) of the cutter and the shaft (5) as seen from the cutter end of
largest diameter; and by a lubricating nipple (19) provided on the
same cutter end wall as said filling lubricating nipple (17) and
functioning to allow lubricating grease to be released from said
bearing-accommodating space (13).
2. An arrangement according to claim 1, characterised in that the
longitudinally extending passageway (16) is disposed centrally in
the cutter shaft (5).
3. An arrangement according to claim 1, characterised in that the
transverse passageway is located in a stress-neutral region of the
cutter shaft (5).
4. An arrangement according to claim 3, characterised in that the
transverse passageway (18) is orientated generally horizontally
when the cutter is mounted on a reamer in its position of use.
5. An arrangement according to claim 1, characterised in that the
transverse passageway (18) extends generally radially out from the
longitudinally extending passageway (16).
6. An arrangement according to claim 1, characterised in that the
transverse passageway (18) extends out in generally opposite
directions from the longitudinally extending passageway (16) and
opens out at two diametrically opposite places on the shaft
(5).
7. (canceled)
8. An arrangement according to claim 2, characterised in that the
transverse passageway is located in a stress-neutral region of the
cutter shaft (5).
Description
[0001] The present invention relates to an arrangement pertaining
to the replenishment of drill cutters with lubricating grease, and
then particularly such cutters as those that are used in drilling
bits for raise drilling.
[0002] A reamer is a drill bit that is normally drawn up through a
predrilled hole by means of a rod extending in the hole. The reamer
includes a carrier to whose upper side there is attached a drilling
tool in the form of a number of so-called cutters. These cutters
rotate against the rock surface, or stone surface, with which they
are in abutment, as the reamer rotates in response to rotation of
the rod. The cutters have a frusto-conical shape and are mounted
with the largest diameter facing outwards, i.e. away from the rod
disposed centrally in said carrier. The cutters are mounted on
shafts accommodated in the attachments carried on the upper side of
the carrier, with the axes of respective cutters extending mainly
radially to the rod.
[0003] In turn, the cutters are provided with bearings by means of
which the cutters are able to rotate about their respective axes.
These bearings and also the seals between cutter and cutter shaft
are kept lubricated with grease fed into the cutter interior. A
shaft is usually filled with lubricating grease, by injecting the
grease through a nipple at one end of the shaft and allowing the
grease to flow out through a nipple hole on the other end of said
shaft. This method functions very effectively provided that the
cutter is not mounted within the reamer. However, when it becomes
necessary to replenish or change the grease, which must done often
when underground conditions are troublesome, it is difficult to
reach the nipple seated at the narrower end of the cutter facing
inwards towards the rod.
[0004] Accordingly, an object of the present invention is to
provide a novel arrangement for refilling drill hole cutters of the
aforesaid kind with lubricating grease.
[0005] This object is achieved with an arrangement according to the
present invention in which there is provided a passageway which
extends along the shaft from the cutter end of largest diameter and
which communicates with a transverse passageway that opens into the
space accommodating a cutter bearing, for the supply of lubricating
grease to said space, and in which there is provided in the cutter
wall of largest diameter a lubricating nipple that functions to
allow lubricating grease to exit from said bearing accommodating
space.
[0006] The invention will now be described in more detail with
reference to a non-limiting embodiment thereof and also with
reference to the accompanying drawings, in which
[0007] FIG. 1 is a schematic perspective view of part of a reamer
having a number of cutters;
[0008] FIG. 2 is a perspective view of a cutter; and
[0009] FIG. 3 is a longitudinally sectioned view of a cutter.
[0010] Shown in FIG. 1 is part of a reamer that includes a carrier
1 which is supported by a rotatable rod 2. The carrier 1 has
disposed on its upper side a number of cutters 3, in the
illustrated case four such cutters. The cutters 3 are mounted in
fasteners 4 provided on the carrier, with the cutter shafts 5
fitted in the fasteners 4. As will be seen, the cutters 3 have a
frusto-conical shape with the narrower end 6 of the cutters facing
inwards towards the rod 2 mounted centrally in the carrier 1. The
cutter shafts 5 are fixedly mounted in the fasteners. In other
words, the cutter shafts 5 are not rotatable in the fasteners 4,
but that the conical outer barrel 7 of the cutters 3 is able to
rotate about the shaft 5 disposed centrally in the cutter. The
cutter has disposed about its outer barrel surface a number of
inserts 8 made, for instance, of tungsten carbide and functioning
to cut the rock or stone in a drilling operation.
[0011] The outer barrel 7 of respective cutters 3 is subjected to
large stresses and strains and is rotatably mounted on the shaft 5
by means of strong bearings 9, 10. Fitted to both end walls of the
barrel 7 are wall elements 11, 12 which seal between the barrel 7
and the shaft 5. There is formed in this way an internally closed
space 13 which accommodates the bearings 9, 10 and also end seals
14, 15. The internal space 13 is normally filled with grease for
lubrication of the bearings 9, 10. The wall elements 11, 12 are
sealed against the barrel 7 and the shaft 5 by means of end seals
14, 15 that include slip seals and O-rings.
[0012] According to the present invention, lubricating grease is
delivered to the bearing accommodating space 13 of the cutter
through a longitudinally extending passageway 16, which extends
centrally in the shaft 5 from that end of the cutter which has the
largest diameter. A filling nipple 17 is provided at this end of
the shaft, such as to enable grease to be delivered to said bearing
space with the aid of a typical grease gun. The passageway 16
extends from said cutter end to a position beyond the innermost
bearing 9 as seen from said end. The passageway 16 communicates at
this position with a transverse passageway 18 which opens into the
bearing-accommodating space 13 beyond the innermost bearing 9. Also
provided in the end wall 12 of the cutter is a drainage nipple 19
through which old lubricating grease can be drained from the cutter
interior when replacing the old grease with fresh grease. The same
end wall 12 will also preferably include an overpressure valve 20
which opens automatically should the pressure in the internal space
13 of the cutter become excessively high, therewith releasing
grease from said space.
[0013] The transverse passageway 18 is preferably provided in a
stress-neutral region of the shaft, particularly so that the outlet
of the transverse passageway 18 into the cutter lies in a
stress-neutral region. The force arrow 21 shown in FIG. 3 indicates
the normal force flow, wherewith the transverse passageway 18 is
disposed generally at right angles to the line of action of the
main force.
[0014] In the case of the illustrated embodiment, the transverse
passageway 18 extends at right angles in both directions from the
passageway 16 provided in the shaft 5. This is a preferred feature
of the invention, since it is then possible to deliver grease to
two diametrically located positions of the shaft 5 within the inner
space 13 of the cutter, therewith ensuring more positively that the
entire space 13 will be filled with grease.
[0015] However, the transverse passageway may extend in only one
direction essentially radially outwards from the longitudinally
extending passageway 16. Alternatively, the transverse passageway
may be orientated to extend generally at right angles to the line
of attack of the main force.
[0016] In practice, the transverse passageway 18 is orientated so
that it will lie generally horizontal when the cutter is fitted in
its position of use on a reamer. As the reamer is used, the
direction of attack of the main force will be generally vertical,
since the reamer is drawn up through a predrilled vertical hole or
bore.
[0017] The arrangement of the lubricating passageways 16, 18 in
accordance with the invention ensures that all bearings in the
cutter 3 will be properly lubricated, so as to avoid damage to the
bearings, despite the fact that lubricating grease is delivered
from the same end as that from which old and spent grease shall
flow out. Despite this, the bearing-grease replenishing nipple 17
may be provided in the larger end wall of the cutter distal from
the rod seated centrally in the reamer, so that easy access can be
had to both the refilling nipple 17 and the drainage nipple 19.
* * * * *