U.S. patent application number 11/921337 was filed with the patent office on 2009-08-20 for spearhead assembly.
This patent application is currently assigned to 2iC Australia Pyt Ltd. Invention is credited to Andrew Beach, Gavin McLeod.
Application Number | 20090206620 11/921337 |
Document ID | / |
Family ID | 37481141 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090206620 |
Kind Code |
A1 |
McLeod; Gavin ; et
al. |
August 20, 2009 |
Spearhead assembly
Abstract
A spearhead assembly (10) comprises a base (12) having an outer
surface (14), a slot (16), a spear point (18) and a guard (20). The
slot (16) is formed in the base (12) and has an opening (22) that
opens onto the outer surface (14). A proximal end of the spear
point (18) is located in the slot (16) and pivotally coupled about
a pivot axis (26) to the base (12). The spear point (18) can pivot
about axis (26) between two positions that are angularly spaced by
180.degree.. The guard (20) is coupled to the proximal end of the
spear point (18) and configured to at least partially occupy the
opening (22) when the spear point is in a location at or between
the two spaced apart positions. The guard (20) acts to minimise the
risk of an operator's hand or glove worn by the operator from being
pinched or caught in the slot (16) between the spear point (13) and
base (12) as the spear point (18) is pivoted between the two
positions.
Inventors: |
McLeod; Gavin; (Ardross,
AU) ; Beach; Andrew; (Boddington, AU) |
Correspondence
Address: |
WOLF GREENFIELD & SACKS, P.C.
600 ATLANTIC AVENUE
BOSTON
MA
02210-2206
US
|
Assignee: |
2iC Australia Pyt Ltd
Canning Vale WA
AU
|
Family ID: |
37481141 |
Appl. No.: |
11/921337 |
Filed: |
May 31, 2006 |
PCT Filed: |
May 31, 2006 |
PCT NO: |
PCT/AU2006/000736 |
371 Date: |
January 22, 2009 |
Current U.S.
Class: |
294/86.1 |
Current CPC
Class: |
E21B 31/20 20130101 |
Class at
Publication: |
294/86.1 |
International
Class: |
E21B 23/00 20060101
E21B023/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 31, 2005 |
AU |
2005902783 |
Claims
1. A spearhead assembly comprising: a base having an outer surface;
a slot formed in the base and having an opening that opens onto the
outer surface; a spear point having a proximal end located in the
slot and pivotally coupled about a pivot axis to the base to enable
pivotal motion of the spear point between two angularly spaced
positions; and, a guard coupled to the proximal end of the spear
point, the guard configured to at least partially occupy the
opening when the spear point is in at least one location at or
between the two positions, or a range of locations at or between
the two positions.
2. The spearhead assembly according to claim 1 wherein the guard
has a side portion of which lies across the opening when the guard
is in the one or range of locations.
3. The spearhead assembly according to claim 2 wherein the portion
of the side lies substantially flush with the opening.
4. The spearhead assembly according to claim 2 wherein the portion
of the side lies proud of the opening.
5. The spearhead assembly according to claim 1 wherein the guard
comprises different side portions which lie substantially flush
with the opening and proud of the opening respectively when the
guard is in different locations between the two positions.
6. The spearhead assembly according to claim 1 wherein the guard is
in the general configuration of a disc.
7. The spearhead assembly according to claim 2 wherein the side
comprises a plurality of radially and/or axially extending and
spaced apart ribs or webs.
8. The spearhead assembly according to claim 1 wherein the guard
comprises a central recess for seating the proximal end of the
spear point.
9. The spearhead assembly according to claim 1 further comprising
an attachment mechanism for attaching the guard to the spear
point.
10. The spearhead assembly according to claim 9 wherein the
attachment mechanism comprises a snap coupling between the guard
and the proximal end of the spear point.
11. The spearhead assembly according to claim 9 wherein the
attachment mechanism comprises a hole or cavity in the guard and a
knob or barb-like projection at the proximal end of the spear point
that is pushed into or through the hole or cavity.
12. The spearhead assembly according to claim 1 wherein the base
comprises two spaced apart walls between which the slot is defined
and the opening is formed; and, two barriers, one of each extending
into the opening on opposite sides of the slot between the spaced
apart walls.
13. The spearhead assembly according to claim 12 wherein the
barriers are in the form of lips.
14. The spearhead assembly according to claim 12 wherein one or
more passages are formed in the barrier and/or between the barrier
and the walls.
15. The spearhead assembly according to claim 1 further comprising
a fluid channel extending through the base and in communication
with the slot to allow a fluid flow through the spearhead
assembly.
16. The spearhead assembly according to claim 1 further comprising
a spear point positioning system that urges the spear point toward,
or holds the spear point in, one of a plurality of angularly spaced
set positions.
17. The spearhead assembly according to claim 16 wherein the
positioning system comprises a plate through which the spear point
extends, the plate being retained on the spear point at a location
where the plate contacts the outer surface of the base.
18. The spearhead assembly according to claim 16 wherein the
positioning system comprises a biasing mechanism that urges the
spear point into one of the plurality of set positions and holds
the spear point in one of the plurality of set positions.
19. The spearhead assembly according to claim 18 wherein the
biasing mechanism acts to bias the plate against the outer surface
of the base.
20. The spearhead assembly according to claim 16 wherein the
opening of the slot comprises a plurality of contiguous lengths
where mutually adjacent lengths lie in respective non-parallel
planes, and wherein the plurality of set positions are positions
where the spear point extends perpendicular to the plane of the
length of the opening from which the spear point extends.
21. The spearhead assembly according to claim 16 wherein the guard
is configured to act as a type of spear point positioning
system.
22. The spearhead assembly according to claim 21 wherein the side
of the guard comprises at least two oppositely disposed straight
length the straight lengths being arranged to extend parallel to
the spear point and wherein a transverse distance between the
straight lengths is slightly smaller than an inner diameter of the
drill pipe or other conduit through which the spear point assembly
travels.
23. A guard for a spearhead assembly having a base, a slot that
opens onto an outer surface of the base, and a spear point with a
proximal end pivotally coupled to the base inside the slot, the
guard comprising a body adapted for coupling to the proximal end of
the spear point and configured to at least partially occupy the
opening.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a spearhead assembly of the
type used in mining and subsurface drilling to enable the coupling
of down hole equipment to a wire line to facilitate the tripping of
the equipment down a drill hole, drill string or casing.
BACKGROUND OF THE INVENTION
[0002] The present Applicant is the applicant in relation to
International publication WO 2004/018831 in relation to a spearhead
assembly. The spearhead assembly in the aforementioned
International publication comprises a base provided with a slot at
one end that opens onto an outer surface of the base. The outer
surface is composed of three contiguous surface portions. A
proximal end of the spear point is located in the slot and
pivotally coupled to the base. An opposite distal end of the spear
point extends or projects beyond the slot. The spearhead assembly
further comprises a spear point positioning system that urges the
spear point toward one of a plurality of angularly spaced
positions. These positions are characterized by the spear point
extending substantially perpendicular to adjacent edges of the
slot. This spear point positioning system holds the spear point in
one of the positions until application of a positive external
force.
[0003] In the claims of this application and in the description of
the invention, except where the context requires otherwise due to
express language or necessary implication, the words "comprise" or
variations such as "comprises" or "comprising" are used in an
inclusive sense, i.e. to specify the presence of the stated
features but not to preclude the presence or addition of further
features in various embodiments of the invention.
[0004] It is to be understood that, if any prior art publication is
referred to herein, such reference does not constitute an admission
that the publication forms a part of the common general knowledge
in the art, in Australia or any other country.
SUMMARY OF THE INVENTION
[0005] According to one aspect of the present invention there is
provided a spearhead assembly comprising: [0006] a base having an
outer surface; [0007] is a slot formed in the base and having an
opening that opens onto the outer surface; [0008] a spear point
having a proximal end located in the slot and pivotally coupled
about a pivot axis to the base to enable pivotal motion of the
spear point between two angularly spaced positions; and, [0009] a
guard coupled to the proximal end of the spear point, the guard
configured to at least partially occupy the opening when the spear
point is in at least one location at or between the two positions,
or a range of locations at or between the two positions.
[0010] The guard has a side portion of which lies across the
opening when the guard is in the at least one or range of
locations.
[0011] The portion of the side may lie substantially flush with the
opening. However in an alternate embodiment the portion of the side
may lie proud of the opening, for example to form a substantially
continuous curve with the outer surface. Indeed the side may
comprise different portions which lie substantially flush with the
opening and proud of the opening respectively when the guard is in
different locations between the two positions. That is the side of
the guard may take different shapes and configurations. In its
simplest form when the guard is in the general configuration of a
disc the side would comprise a simple curved surface having a
linear transverse section. However in an alternative embodiment the
side or portion of the side may be of a complex configuration and
have for example a stepped, wave or zigzag transverse section. One
example of this is where the side comprises a plurality of radially
and/or axially extending and spaced apart ribs or webs. In this
embodiment the spacing between the ribs or webs forms one or more
channels or grooves in the radially outermost surface.
[0012] It is further envisaged that the guard may comprise a
central recess for seating the proximal end of the spear point. The
spearhead assembly may further comprise an attachment mechanism for
attaching the guard to the spear point. In one possible embodiment,
the attachment mechanism comprises a snap coupling between the
guard and the proximal end of the spear point. This can be
facilitated by the provision of a hole or cavity in the guard and a
knob or barb-like projection at the proximal end of the spear point
that is pushed into or through the hole or cavity.
[0013] In one embodiment the base comprises two spaced apart walls
between which the slot is defined and the opening is formed; and,
two barriers, one of each extending into the opening on opposite
sides of the slot between the spaced apart walls. In one
embodiment, the barriers may be in the form of lips.
Advantageously, one or more passages are formed in the barrier
and/or between the barrier and the walls.
[0014] The spearhead assembly may further comprise a fluid channel
extending through the base and in communication with the slot to
allow a fluid flow through the spearhead assembly.
[0015] The spearhead assembly may further comprise a spear point
positioning system that urges the spear point toward, or holds the
spear point in, one of a plurality of angularly spaced positions.
The spear point positioning system may comprise a plate through
which the spear point extends, the plate being retained on the
spear point at a location where the plate contacts the outer
surface of the base.
[0016] In one embodiment, the spear point positioning system
further comprise a biasing mechanism that urges the spear point
into one of the plurality of set positions and holds the spear
point in one of the plurality of set positions. Moreover, the
biasing mechanism acts to bias the plate against the outer surface
of the base.
[0017] In one embodiment of the invention, the opening of the slot
comprises a plurality of contiguous lengths where mutually adjacent
lengths lie in respective non-parallel planes, and wherein the
plurality of set positions are positions where the spear point
extends perpendicular to the plane of the length of the opening
from which the spear point extends.
[0018] In an alternate embodiment, the guard itself may be
configured to act as a type of spear point positioning system. In
this embodiment, the side of the guard comprises at least two
oppositely disposed straight length the straight lengths being
arranged to extend parallel to the spear point and wherein a
transverse distance between the straight lengths is slightly
smaller than an inner diameter of the drill pipe or other conduit
through which the spear point assembly travels. It will be
appreciated that by dimensioning the straight lengths in this way,
when the spear point assembly is initially entering a drill pipe or
other conduit, and the spear point is pivoted more than say a few
degrees away from the longitudinal axis of the assembly, contact of
one of the straight edges with the opening of the drill pipe or
conduit will cause pivoting of the guard and spear point so as to
lie substantially parallel to the longitudinal axis. Further, once
inside the drill pipe, pivoting of the guard or spear point
marginally away from the longitudinal axis will result in contact
of one of the straight edges with the inner diameter of the pipe or
conduit thereby limiting any further pivotal movement away from the
longitudinal axis. This will accordingly maintain the spear point
within a narrow arc from the longitudinal axis thereby
substantially ensuring coupling with an overshot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Embodiments of the present invention will now be described
by way of example only with reference to the accompanying drawings
in which:
[0020] FIG. 1 is a representation of an embodiment of the spearhead
assembly in accordance with the present invention;
[0021] FIG. 2 is an enlarged view of the portion of the spearhead
assembly with the spear point inclined from a longitudinal axis of
the spearhead assembly;
[0022] FIG. 3 is an enlarged view of the spearhead assembly with
the spear point extending perpendicular to the longitudinal axis of
the spearhead assembly;
[0023] FIG. 4 is an isometric view from the front of a guard
incorporated in the spearhead assembly;
[0024] FIG. 5 is an isometric view from the top of the guard shown
in FIG. 4;
[0025] FIG. 6 is an isometric view from a lower edge of the
guard;
[0026] FIG. 7 is an isometric view of the base incorporated in the
spearhead assembly; and,
[0027] FIG. 8 is a view of section AA of the base depicted in FIG.
7.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0028] Referring to the accompanying drawings an embodiment of the
spearhead assembly 10 in accordance with the present invention
comprises a base 12 having an outer surface 14, a slot 16 (see in
particular FIG. 7), a spear point 18 (shown in FIGS. 1-3) and a
guard 20 (shown in FIGS. 1-6). The slot 16 is formed in the base 12
and has an opening 22 that opens onto the outer surface 14. The
spear point 18 has a proximal end located in the slot 16 and
pivotally coupled about a pivot axis 26 to the base 12 to enable
pivotal motion of the spear point 18. The spear point 18 can pivot
about the axis 26 between two angularly spaced positions. These two
positions are spaced by approximately 180.degree. and with
reference to FIG. 1 correspond to the spear point 18 being pivoted
about axis 26 in an anti-clockwise direction to extend
substantially perpendicular to a longitudinal axis 28 and pointing
into the page, and a second position where the spear point 18 is
pivoted in a clockwise direction about axis 26 to lie perpendicular
to the longitudinal axis 28 and pointing out of the page.
[0029] The guard 20 is coupled to the proximal end of the spear
point 18 and configured to at least partially occupy the opening 22
when the spear point is in a location at or between the
aforementioned two spaced apart positions. Consequently, the guard
acts to minimise the risk of an operator's hand or glove worn by
the operator from being pinched or caught in the slot 16 between
the spear point 18 and the base 12 as the spear point 18 is pivoted
between the two positions. Thus embodiments of the spear head
assembly 10 and in particular guard 20 assist in reducing the
likelihood of injury or accident during raising and lowering of a
device to which the assembly 10 is attached, as well as during the
coupling and decoupling of the spear point assembly with an
overshot.
[0030] With particular reference to FIGS. 7 and 8, the base 12
comprises a pair of spaced apart walls 30 and 32 between which the
slot 16 is defined, and the opening 22 is formed. The walls 30 and
32 project from one end of a spigot or a tube 34. The walls 30 and
32 each have a generally semi-cylindrical outer surface which
constitutes a major portion of the outer surface 14 of the base 12;
and respective inner planar walls 31 and 33. An axial channel 36 is
formed in the tube 34 that communicates with the slot 16. A
concavely curved wall 38 is provided in the base 12 between the
walls 30 and 32, and onto which the channel 36 opens. Holes 40 and
42 are formed in the walls 30 and 32 respectively co-axial with the
pivot axis 26. These holes receive a pivot pin 44 that also extends
through the proximal end of the spear point 18 and the guard 20,
coupling the spear point 18 to the base 12.
[0031] The opening 22 of the slot 16 can be considered as
comprising a plurality of contiguous lengths which are shown most
conveniently in FIG. 8 as lengths 46, 48, 50, 52 and 54. These
lengths correspond with edges formed between the outer peripheral
surfaces of the walls 30 and 32 and their corresponding inner
planar surfaces 31 and 33. In general, the lengths 46-54 trace a
path in the shape of an inverted U. It will be further observed
that a plane containing the length 46 is inclined (ie not parallel)
to a plane containing a length 48, which in turn is not parallel to
a plane containing a length 50, which in turn is not parallel to a
plane containing a length 52, which lies in a plane not parallel to
a plane containing a length 54.
[0032] Barriers, in the form of upstanding lips 56 and 58 project
into the opening 22 between the walls 30 and 32. More particularly,
the lip 56 projects into the length 46 of the opening, while the
lip 58 projects into the length 54 of the opening. The lips 56 and
58 have respective surfaces interior of the slot 16 that follow the
curvature of the concave wall 38. In this embodiment, the lips 56
and 58 extend upwardly only a relatively short distance and
terminate at a level short of the holes 40 and 42. The lips 56 and
58 act to limit the pivotal motion of the spear point 18 as well as
further assist in the prevention of pinching of an operators hand
or glove. Passages 60 are formed between opposite lateral edges of
each of the lips 56 and 58 and the adjacent walls 30 and 32.
[0033] Referring to FIGS. 4-6, the guard 20 comprises a body 62
having opposite planar surfaces 64 and 66 that face the inner
planar walls 31 and 33 respectively, and a generally arcuate
radially outer surface, or side 68 between the surfaces 64 and 66.
A central recess or seat 70 is formed in the body 62 for receiving
the proximal end of the spear point 18. A hole 72 is formed through
the body 62 at the bottom of the recess 70. The radial outer
surface or side 68 can be considered as comprising three parallel
radially extending ribs or webs 74 and an axially extending rib 76.
The webs 74 and 76 lie in the vicinity of the opening 22
irrespective of the pivotal position of the spear point 18. However
depending on the particular pivotal location of the spear point 18
the webs 74, 76 may lie inside or outside of the actual opening 22.
Their actual position relative to the opening is not per se
critical to the working of the invention. The function performed by
the webs 74, 76 and moreover the guard 20 as a whole is to
substantially occupy the opening 22 to prevent pinching of an
operators hand or glove.
[0034] Channels or grooves 78 are formed between the webs 74, 76,
which provide flow paths that communicate with the passage 60 and
channel 36 so that drilling fluids or naturally occurring fluids
within a drill hole are able to flow through the spearhead assembly
10.
[0035] By forming a small barb like projection or knob at the
proximal end of the spear point 18 and having an outer diameter
largely greater than the diameter of the hole 72, an attachment
mechanism is effectively formed to enable the easy coupling of the
guard 20 to the spear point 18.
[0036] The illustrated embodiment of the spearhead assembly 10
includes a spear point positioning system 80 of a type described in
International publication No. WO 2004/018831, the contents of which
is incorporated herein by way of reference. Nevertheless, by way of
brief explanation, the spear point positioning system 80 operates
to urge the spear point 18 toward, and/or hold the spear point 18
in, one of a plurality of angularly spaced positions. These
positions are characterised by the spear point 18 extending
perpendicular to particular lengths 46-54 of the opening 22 from
which it extends. For example, with reference to FIG. 1, the spear
point position system operates to hold the spear point 18 in a
position where it extends perpendicular to the length 50 of the
opening 22. In FIG. 2, the positioning system 80 holds the spear
point 18 at a position perpendicular to a plane containing the
length 48 of the opening 22, and in FIG. 3 the positioning system
holds the spear point 18 to extend perpendicular to a plan
containing the length 46 of the opening 22. The positioning system
80 comprises a plate in the form of a washer 82 retained on the
spear point 18, and a helical spring 84 also retained on the spear
point 18 and acting to bias the washer 82 against the outer surface
14 and more particularly, the lengths 46-54 of the opening 22.
[0037] The positioning system 80 operates to provide a snap action
when the spear point 18 is pivoted between the lengths 46-54 of the
opening 22. More particularly, the system 80 acts to bias or snap
the spear point 18 to lie perpendicular to the angularly closest
length. For example, consider the spear point 18 being moved from a
position shown in FIG. 1 where it extends perpendicular to the
length 50, to the position shown in FIG. 2 where it extends
perpendicular to the length 48. As the spear point 18 is being
pivoted about the axis 26, the system 80 will urge the spear point
toward the perpendicular of length 50 until it passes beyond the
midway point to the perpendicular to the length 48. Thus if one
were to release the force applied to the spear point 18 at that
time, the system 18 would act to snap the spear point 18 back to
the position shown in FIG. 1. However once the spear point 18 is
rotated past the midway point, the system 80 acts to snap the spear
point to a position perpendicular to the length 48.
[0038] Now that embodiments of the present invention have been
described in detail it will be apparent to those skilled in the
relevant arts that numerous modifications and various may be made
without departing from the basic inventive concepts. For example,
the base 12 is described and illustrated as including an axial
passage 36. However in embodiments where the spear point is used in
dry holes, the passage 36 is not required. Also in these
circumstances, the channels 78 in the outer radial surface of the
guard 20 are not necessary. Further, the configuration of the guard
20 is almost limitless. For example with reference to the guard 20
as illustrated, it may be modified by the inclusion of further
axial ribs parallel to the axial rib 76 so that the outer surface
68 takes a mesh like appearance. Indeed in an alternate embodiment,
a steel mesh or grid may be placed in the channels or grooves 78.
Further, the entire guard 20 may be in the form of a wire mesh
structure that is coupled to the proximal end of the spear point
18. In an alternate embodiment to that depicted in the drawings,
the spear point 18 and the guard 20 could be moulded or otherwise
constructed as a single piece.
[0039] It will be noted in particular from FIGS. 4 and 6 that the
outer most ribs or webs 74 comprise respective straight edges or
sides 79. In a further variation, it is possible to laterally
extend the straight edges or sides 79 so that when the spear point
18 is in alignment with the longitudinal axis 28, the sides 79 lie
marginally inside an inner diameter of the drill pipe through which
a device attached to the spear point assembly 10 is tripped, (ie
the transverse distance between the lengths 79 on opposite sides of
the guard 20 is slightly smaller than the inner diameter of the
pipe). This has the effect of self centering the spear point 18
when the assembly 10 enters and travels through the drill pipe.
This obviates the need for the positioning system 80 particularly
insofaras it operates to maintain the spear point 18 in general
alignment with the axis 28, and longitudinal axis of the drill
pipe. In this regard, it will be appreciated that by dimensioning
the length 79 as described above, the spear point 18 will be
maintained within a narrow arc from the axis 28 when inside a drill
pipe due to contact of the lengths 79 with the inner diameter of
the drill pipe upon pivoting of the guard 20 and the spear point 18
more than only several degrees away from alignment with the axis
28.
[0040] All such variations and modifications together with others
that would be obvious to a person of ordinary skill in the art are
deemed to be within the scope of the present invention the nature
of which is to be determined from the above description.
* * * * *