Note: Descriptions are shown in the official language in which they were submitted.
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This inven-tion relates to a transportable boring machine for
the ln situ boring oE work pieces, such as heavy machinery bearings and
the like.
For excm~ple, when bearings wear out it is oEten possible to
restore the bearing to its orlginal condition by filling the worn part
with weld metal and machining -to the original tolerance. In many cases
it is impractical to transport the machinery to a workshop, particularly
heavy machinery used in -the mining industries. For example, over a
period of time the bearings in the arms of front-end loaders become worn
and these bearings can be repaired in the manner just described~ To
avoid having to take the equipment to the workshop, transportable
- machining apparatus is employed.
An example of prior art machining apparatus is described in
~ Canadian Patent No. 1,116,892, which issued on December 12, 1982. This
- machining apparatus comprises a drive-housing which is mounted over a
hole to be bored, a machining bar passing through the drive housing and
driven by means of a pulley arrangement, and a feed screw for advancing
the machining bar into the hole. I'his apparatus is cumbersome and
-~ difficult to align with the axis of the hole to be bored to the required
~- degree of accuracy. The length of the machine, caused by the presence
of the feed screw, makes it impractical to use in applications where
space is restricted. The apparatus is also time consuming and akward to
~25 install.
An object of the invention is to alleviate the
aforementioned problems of the prior art apparatus.
According to the present invention there is provided a
transportable boring machine for the in situ boring of workpieces,
comprising: a telescopic assembly comprising a rotatable drive shaft
for connection to a tool bit carrier rod; means for rigidly mounting
-- said assen~ly on the workpiece over a hole to be bored; means for
rotating said drive shaft and means for retracting and extending said
telescopic assembly as said drive shaft rotates to advance said tool bit
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carrier rod into the hole.
The drive shaft is preEerably driven by means of a hydraulic
motor and the telescopic assembly extended by hydraulic actuators
controlled from a common power source permitting the ra-te of rotation in
advance to be varied. Th telescopic assembly is normally attached to
the workpiece by means of support bearings welded -thereto.
In the preferred embodiment -the telescopic assembly
comprises an intermediate sleeve between the drive shaEt and an outer
sleeve. The intenmediate sleeve is slideable with respect -to the outer
shaft and the drive shaft is rotatable with respect to the intermediate
sleeve. The intermediate sleeve carries a mounting plate for the
hydraulic motor and to which the hydraulic actuators are also attached.
The drive shaft is hollow so that -the tool bit carrier rod can be passed
through it.
This arrangement can be made compact and easy to install.
The hydraulic drive and actuators permit accurate variable control over
the feed rate and rotational speed.
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According to a further aspect of the invention there is
provided a method of carrying out in situ boring of workpieces,
comprising passing a centring rod through at least one hole to be bored,
~25 a pair of support bearings being carried on said rod, aligning said
~; centring rod through said at least one hole by means of a pair of cone
bearings, rigidly attaching said support bearings to the workpiece,
removing said cone bearings and mounting a boring machine with a hollcw
drive shaf-t over a tool bit carrier rod passing through said suppor-t
bearings, said drive shaft being telescopically extendable and
retractable to advance the rod with a tool bit connected thereto into
the hole.
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By mounting the support bearings in this manner, the tool
bit carrier rod can be accurately allgned wi-th the axis of the hole,
particularly in the case of two or more in-line holes, such as are Eouncl
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in the bearing arms of a front-end loader.
The invention will now be described in more de-tail, by way
of example only with reference to the accanpanying drawings in which:
- Figure la is a plan view of the bearing arms of a front-end loader
shcwing the initial stage of installation oE a boring machine in
accordance with -the invention;
- Figure lb shows the boring machine installed on one of the bearing
arms of the loader;
- Figure 2a is a side view of a telescopic assembly forming part of the
b~ring machine;
- Figure 2b is a plan view of the assembly shown in Figures 2a;
: - Figure 3 is an exploded view of the inner drive shaft of the assembly
with the cone bearings;
- Figure 4 is an exploded view of the intermediate sleeve, mo-tor
mounting plate, and motor;
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- Fig~re 5a is a side view of the telescopic assembly and drive mo-tor;
~25
- Figure Sb is a plan view of the assembly shown ln Figure 5a;
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- Figure 6a is a cross-sectional view of the support bearing mounted
over a hole in a workpiece;
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~ - Figure 6b is a plan view of the support bearing shown in Figure 6a;,~
- Figure 7a is a side elevational view of a tool carrier;
- Figure 7b is a plant view of the tool carrier shown in Figure 1a;
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- ~igure ~ shows the tool carrier rod and tool holder;
- Figure 9 is a side view of a trolley on which the machinlng
apparatus is mounted;
Fi~ure lO is a schematic diagram of -the hydrau:Lic circuit.
Figure la and la show a pair of æms 1, 1' with a pair of
respec-tive bores 2, 2'. The bores 2, 2' in this case æ e be æings fox
pivotally supporting the bucket of the front-end loader.
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When the bearings have become worn and are in need of
repair, they can be bored out with the apparatus in accordance with the
invention, if necess æy after first filling them with weld metal. In
order to install the apparatus, a tool carrier bar 3 is passed through
the bores 2, 2' and aligned by means of cones 4, 4'. Subsequently the
support bearings 5, 5' m~unted on the bar are brought against the inner
faces of the æms l, li and welded thereto as shown in Figure lb. The
support bearings 5, 5' æe cone bearings of the type shown in Figures 6,
6a, which are adjustable and allow accurate alignment of the tool
carrier rod
When the support bearings 5, 5' have been welded in place,
as shown in Figure lb, the telescopic assembly 6 with motor 7 is
attached to the lower support be æ ing 5' by suitable attach~ent means.
~ m e tool c ærier bar 3 is then passed through the telescopic assembly 6
- and locked thereto in a manner described below.
~;~ 30 Referring to Figures 2a and 2b, the telescopic assembly 6
comprises an outer sleeve 8 fixed to a lower bearing plate 9 at-tached to
the support be æing 5' by means of bolts passing -through holes lO, lO'
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in wing portions thereof. The outer sleeve 8 has a longitudinal keyway
11 On its inner surface. ~ pair of piston-and-cylinder hydraulic
actuators 12, 12' are attached at their lower end to the wing portions
oE the lcwer mounting plate 9. ~eferring to Figu~e 4, an intermediate
sleeve 13 is slideahly fitted within -the outer sleeve 8. A key 14
located in recess lS located in -the external periphery of the
intermediate sleeve 13 slides in keyway 11 of -the outer sleeve 8. A
motor support plate 16 is attached to the upper end oE the intermediate
sleeve 13. Ilydraulic motor 17 is mounted under the over hanging part of
the motor mounting plate 16. Motor shaft 18 extends above the mounting
plates 16 and carries a gear 19 for driving a drive shaft in the
telescopic assen~ly. Cone bearings 20, 20' are fitted in each end of
the intermediate sleeve 13. As shown in Figures 5 and 5b, within the
intermediate sleeve 13 is rotatably mounted a hollow drive shaft 21.
lS The drive shaft 21 is rotatable in the cone bearings 20, 20', but is
prevented from sliding longitudinally relative to the intermediate
sleeve 13, although of course the drive shaft 21 is slidable with the
intermediate sleeve 13 in relation to the ou-ter sleeve 8. The inner
sleeve 21 carries at its upper end a sprocket wheel 22 connected by a
drive chain to a similar sprocket wheel 23 on the hydraulic motor 7
carried by the motor mounting plate 16 attached to the intermediate
~- sleeve 13,
The inner drive shaft 21 is shown in more detail in Figure
3. Cone bearings 20, 20' are held in place by means of snap rings 24,
located in recesses such as recess 25. The drive shaft 21 is hollow so
that the tool carrier rod 3 can be passed therethrough. l~he drive shaft
21 is locked to the tool carrier rod by means of a key 26 which passes
through bore 27 in the wall of the drive shaft. A retaining ring 28
holds the key in place to prevent rotation of -the tool relative to the
drive shaft. Retaining ring 29 between the cone bearing 20 and snap
ring 24 acts as an oil seal.
To pennit tightening of the drive chain, as shot~n in Figures
~; 35 4 and 5b, the motor is actually mounted on an eccentric plate 30 which
is at-tached to -the mounting plate 16 by bolts 31, 31' passing through
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slot 32,32'.
As shown in Figure 8, a tool bit 40 fits in a
channel 41 in the end 42 of the tool carrier bar 3. The
tool bit 40 is locked in the channel by means of allen screws
43. A rnagnetic dial indicator can be provided -to facilitate
adjustment of the tool bit.
The -tool carrier bar 3 has been described as -the same as the
centering bar illustrated in Figure la. It will be unclers-tood that
diEferent bars can in fact be used for cen-tering and machining
operations.
Figure 10 shows a trolley 60 containing the hydraulic pcwer
source and controls for transporting the apparatus to the work site.
The trolley contains a hydraullc pump with variable output driven by a
120 volt a~c. electric motor, an oil reservoir and controls for varying
the speed of rotation and the rate of feed of the tool bit. The
-hydraulic's schematic diagram as sh~wn in Figure 11.
After installation of the apparatus, as shown in Figure lb,
on insertion of the tool carrier bar with tool bit, the motor is started
and the drive shaft driven in rotation. This in turn drives the tool
~; carrier bar 3, and thus the tool, which on entering the hole machines
~ 25 away the metal. At the same time the telescopic assembly 6 is;~ retracted, in the case of the hole 2, 21 in Figure lb, and the tool bit
gradually advances through the hole. If the upper hole 2 is being
mach med, the teIescopic assembly would normally be extended to advance
the tool bit into the hole.
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The hydraulic lines can be coupled to the motor and
actuators by means of quick couplings. As the electric motor drives the
variable output p~mp (to vary the speed of rotation), the oil is fed to
an accumulator which is maintained under pressure. The accumulator
S supplies oil to the hydraulic actuators through a 4-way valve and to
check valves which ensure the stc~bility of the automatic feed. The
return oil flows back through an adjustable restriction valve to the
4-way valve and the reservoir. As a result the automatic hydraulic feed
does not operate under constant pressure on one side of the cylinder,
but rather under pressure on both sides of the cylinder. The volume on
one side of the cylinder is reduced through a precision restriction.
The rotational control is effective by means of a 3-way
valve. ~ -
~- The described apparatus has many advantages, of which the
compact dimensions should be mentioned in that they permit machining
operations to be carried out in a restricted space. The variable and
; precise rotational and automatic feed permit the most effective cut to
- 20 be selected for the work piece. The appara-tus can be quickly installed,
` and different types of machining operations carried out, such as
internal, external, and perpendicular operations, i.e. internal boring
; operations, machining of the outer side wall of a collar around the
~; hole, and machining of the end face.
The use of the support bearings 5r 51 enables the apparatus
to be extremely accurately aligned in-the holes, particularly in the
~-; case of the in-line boring of two or more holes, as illustrated in
E`igures la and lb for a front-end loader. The remote hydraulic control
also permits a rapid displace ent of t e tool tetween each cut.
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