U.S. patent number 3,797,591 [Application Number 05/330,034] was granted by the patent office on 1974-03-19 for trigger mechanism for down-hole adjustable hydraulic fishing jar.
This patent grant is currently assigned to Baker Oil Tools, Inc.. Invention is credited to William O. Berryman.
United States Patent |
3,797,591 |
Berryman |
March 19, 1974 |
**Please see images for:
( Certificate of Correction ) ** |
TRIGGER MECHANISM FOR DOWN-HOLE ADJUSTABLE HYDRAULIC FISHING
JAR
Abstract
A down-hole adjustable hydraulic fishing jar for removing stuck
objects from a well bore in which hydraulic fluid within a
compression chamber by-passes a compression piston through an
unrestricted flow passage normally closed by a valve. The valve is
instantaneously opened by a trigger mechanism adjustable down-hole
to vary the tension on the running-in string required to trigger
the valve to the open position. The jar is operative repetitively
in any selected adjusted condition. An adjusting rig is assembled
with the trigger to have limited freedom of rotation during jarring
operations and to rotatively drive the trigger to enable
adjustment.
Inventors: |
Berryman; William O. (Houston,
TX) |
Assignee: |
Baker Oil Tools, Inc. (Los
Angeles, CA)
|
Family
ID: |
23288024 |
Appl.
No.: |
05/330,034 |
Filed: |
February 6, 1973 |
Current U.S.
Class: |
175/296;
175/303 |
Current CPC
Class: |
E21B
31/113 (20130101); E21B 23/006 (20130101) |
Current International
Class: |
E21B
31/00 (20060101); E21B 31/113 (20060101); E21B
23/00 (20060101); E21b 001/06 (); E21b
001/10 () |
Field of
Search: |
;175/296,297,303,302
;166/178 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Brown; David H.
Attorney, Agent or Firm: Kriegel; Bernard
Claims
I claim:
1. In a hydraulic fishing jar adapted to be run into a well on a
fishing string and connected to a fish in the well bore, inner and
outer elongated bodies telescopically interengaged, means defining
between said bodies a hydraulic fluid chamber, compression piston
means in said chamber operable upon telescopic movement of said
bodies in one direction to compress the hydraulic fluid in said
chamber, valve means in said chamber including means providing a
by-pass flow passage, a valve member for normally closing said flow
passage and shiftable to an open position at which said compressed
hydraulic fluid is released to said flow passage, trigger means
responsive to tensioning of said fishing string to compress the
hydraulic fluid in said chamber for moving said valve member to
said open position, hammer and anvil means on said bodies movable
into engagement by the tension in said fishing string when said
valve member is moved to said open position, and adjusting means
for adjustably positioning said trigger means with respect to said
valve member for adjusting the maximum tension applicable to said
fishing string, said adjusting means idling during jarring
operations.
2. In a hydraulic fishing jar as defined in claim 1, said means for
adjustably positioning said trigger means being responsive to
manipulation of said fishing string.
3. In a hydraulic fishing jar as defined in claim 1, said means for
adjustably positioning said trigger means including holding means
engageable for connecting said trigger means to one of said bodies
and releasable upon rotation of said trigger means relative to said
one of said bodies, and the other of said bodies and said adjusting
means having means for rotating said trigger means responsive to
relative telescopic movement of said bodies.
4. In a hydraulic fishing jar as defined in claim 1, said means for
adjustably positioning said trigger means including holding means
engageable for connecting said trigger means to one of said bodies
and releasable upon rotation of said trigger means relative to said
one of said bodies, and the other of said bodies and said adjusting
means having means for rotating said trigger means responsive to
relative telescopic movement of said bodies, and means for moving
said trigger means to adjusted positions with respect to said one
of said bodies and said valve member when said trigger means is
released from said one of said bodies.
5. In a hydraulic fishing jar as defined in claim 1, said trigger
means and one of said bodies having coengageable holding means
releasable to permit adjustment of said trigger means with respect
to said one of said bodies and said valve member, and means for
moving said trigger means to adjusted positions determined by
tension applied to the fishing string.
6. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member.
7. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
means for moving said member longitudinally of said one of said
bodies when said ribbed portions are released for re-engagement of
said ribbed portions at a location spaced longitudinally of said
one of said bodies.
8. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
means for moving said member longitudinally of said one of said
bodies when said ribbed portions are released for re-engagement of
said ribbed portions at a location spaced longitudinally of said
one of said bodies in responsive to telescopic movement of said
bodies.
9. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
means for moving said member longitudinally of said one of said
bodies when said ribbed portions are released for re-engagement of
said ribbed portions at a location spaced longitudinally of said
one of said bodies in response to telescopic movement of said
bodies and depending upon the magnitude of compression of said
hydraulic fluid.
10. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
means for moving said member longitudinally of said one of said
bodies when said ribbed portions are released for re-engagement of
said ribbed portions at a location spaced longitudinally of said
one of said bodies, said ribbed portions comprising threaded
segments.
11. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
including ratchet means for holding said member in position for
re-engagement of said ribbed portions at adjusted longitudinally
spaced locations.
12. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
including ratchet means for holding said member in position for
re-engagement of said ribbed portions at adjusted longitudinally
spaced locations, said ratchet means including resilient ratchet
arms complemental to said ribbed portions.
13. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, and
means for moving said member longitudinally of said one of said
bodies when said ribbed portions are released for re-engagement of
said ribbed portions at a location spaced longitudinally of said
one of said bodies, including a spring normally biasing said member
in one direction, and means movable with one of said bodies into
engagement with said member to move the latter in the other
direction.
14. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions being
engageable and releasable upon rotation of said member, the other
of said bodies and said adjusting means having means responsive to
relative telescoping of said bodies for rotating said member, means
for moving said member longitudinally of said one of said bodies
when said ribbed portions are released for re-engagement of said
ribbed portions at a location spaced longitudinally of said one of
said bodies, including a spring normally biasing said member in one
direction, and means including said valve member movable with one
of said bodies into engagement with said trigger member to move the
latter in the other direction in response to telescopic movement of
said bodies.
15. In a hydraulic fishing jar as defined in claim 1, said means
defining said hydraulic fluid chamber comprising upper and lower
seal means between said bodies, one of said seal means being a
floating piston for compensating for the pressure of fluid in the
well.
16. In a hydraulic fishing jar as defined in claim 1, said
compression piston means comprising an annular piston between said
bodies and having a peripheral wall spaced from one of said bodies
to provide a fluid passage, and including valve means carried by
said one of said bodies to close said passage upon telescopic
movement of said bodies.
17. In a hydraulic fishing jar as defined in claim 1, said trigger
means comprising a tubular member rotatable relative to said
bodies, said member and one of said bodies having opposed angularly
spaced ribbed and unribbed portions, said ribbed portions and
unribbed portions being engageable and releasable upon rotation of
said member, said adjusting means and the other of said bodies
having pin and slot means responsive to relative telescoping of
said bodies for rotating said adjusting means, and said adjusting
means and said member having means for rotating said member to
engage and release said ribbed portions.
18. In a hydraulic jar as defined in claim 17, said means for
rotating said member including a slot in one of said member and
said adjusting means extending angularly between opposed sides
walls and a lug on the other of said member and said adjusting
means disposed in said slot and engageable with said side walls for
rotating said member.
19. In a hydraulic jar adapted to be run into a well on a fishing
string and connected to a fish in the well bore, inner and outer
telescopic bodies, means including longitudinally spaced seals
defining between said bodies a hydraulic fluid chamber, compression
piston means including an annular piston carried by one of said
bodies and shiftable longitudinally in said chamber by the other of
said bodies upon telescopic movement of said bodies in one
direction to compress hydraulic fluid in said chamber, valve means
in said chamber including means providing by-pass flow passage
communicating with said chamber at opposite ends of said piston, a
valve member normally closing said flow passage and shiftable to an
open position to allow hydraulic fluid to by-pass said piston,
trigger means carried by one of said bodies and opposing said valve
member to move said valve member to said open position upon
predetermined movement of said bodies in said direction, hammer and
anvil means on said bodies movable into engagement by the tension
in said fishing string in response to further telescopic movement
of said bodies in said one direction when said valve member is
moved to said open position, and means for adjustably positioning
said trigger means with respect to said valve member for adjusting
the maximum tension applicable to said fishing string, said
adjusting means idling during jarring operations.
20. In a hydraulic fishing jar as defined in claim 19, means
responsive to manipulation of said fishing string for adjusting the
position of said trigger means, including holding means engageable
for connecting said trigger means to one of said bodies and
releasable upon rotation of said trigger means relative to said one
of said bodies, and the other of said bodies and said adjusting
means having means for rotating said trigger means responsive to
relative telescopic movement of said bodies.
21. In a hydraulic fishing jar as defined in claim 19, said trigger
means and one of said bodies having coengageable holding means for
holding said trigger means in longitudinally adjusted positions on
said one of said bodies, said holding means being releasable and
engageable upon rotation of said trigger means with respect to said
one of said bodies, means for enabling longitudinal movement of
said trigger means with respect to said one of said bodies when
said holding means are released, and companion pin and slot means
on said adjusting means and one of said bodies for rotating said
trigger means responsive to telescopic movement of said bodies,
said pin and slot means comprising a compound slot having
longitudinally extended, circumferentially spaced sections and
connecting sections defined by inclined walls for camming said pin
between said longitudinally extended sections to release said
holding means and engage said holding means, said adjusting means
and said trigger means having means allowing freedom of rotation of
said adjusting means relative to said trigger means during jarring
operations.
22. In a hydraulic fishing jar as defined in claim 19, said trigger
means and one of said bodies having coengageable means for holding
said trigger means in longitudinally adjusted positions on said one
of said bodies, said holding means being releasable and engageable
upon rotation of said trigger means with respect to said one of
said bodies, means for enabling longitudinal movement of said
trigger means with respect to said one of said bodies when said
holding means are released, and companion pin and slot means on
said adjusting means and one of said bodies for rotating said
trigger means responsive to telescopic movement of said bodies,
said pin and slot means comprising a compound slot having
longitudinally extended, circumferentially spaced sections and
connecting sections defined by inclined walls for camming said pin
between said longitudinally extended sections to release said
holding means and engage said holding means, said adjusting means
and said trigger means having means allowing freedom of rotation of
said adjusting means relative to said trigger means during jarring
operations, and means for moving said trigger means longitudinally
when said pin is in one of said longitudinally extended sections
and said holding means are released.
23. In a hydraulic fishing jar as defined in claim 19, said trigger
means and one of said bodies having coengageable holding means for
holding said trigger means in longitudinally adjusted positions on
said one of said bodies, said holding means being releasable and
engageable upon rotation of said trigger means with respect to said
one of said bodies, means for enabling longitudinal movement of
said trigger means with respect to said one of said bodies when
said holding means are released, and companion pin and slot means
on said adjusting means and one of said bodies for rotating said
trigger means responsive to telescopic movement of said bodies,
said pin and slot means comprising a compound slot having
longitudinally extended, circumferentially spaced sections and
connecting sections defined by inclined walls for camming said pin
between said longitudinally extended sections to release said
holding means and engage said holding means, means for moving said
trigger means longitudinally when said pin is in one of said
longitudinally extended sections and said holding means are
released, including spring means biasing said trigger means to a
lowermost position, and means responsive to telescopic movement of
said bodies in said one direction to move said trigger means to an
upwardly adjusted position depending upon the tension of said
fishing string, said adjusting means including a ring rotatably
mounted with respect to said trigger means, said ring and said
trigger means having pin and slot means for allowing freedom of
rotation therebetween during rotation of said trigger means by the
first-mentioned pin and slot means during jarring operations.
Description
Fishing jars are employed when it becomes necessary to remove from
a well bore extending into the earth, such as oil or gas well,
various "fish," such as a length of drill pipe or a subsurface tool
which may be stuck in the well bore. Typically, fishing jars are
run at the lower end of a string of drill pipe, commonly referred
to as the fishing or running string, in a position above the
fishing tool, which may be a spear or overshot adapted to engage
and grip the fish so that the fish may be pulled from the well bore
upon pulling the fishing string. The jar is employed for the
purpose of applying hammer blows tending to release the stuck fish
while the fishing string is under tension. Jars of the hydraulic
type, in general, comprise a pressure chamber containing a quantity
of hydraulic fluid which is compressed when an upward strain or
tension is applied to the running string, the compressed hydraulic
fluid bleeding through a restricted flow passage to enable the
pulling rig at the surface of the earth to apply the necessary
strain or tension to the running string before the compressed
hydraulic fluid is allowed to rapidly by-pass the restricted
passage so that the jarring hammer impacts against an anvil to
apply an upward hammer blow.
Adjustment of the conventional hydraulic jars to vary the metering
time before the jar applies the hammer blow requires that the
fishing string and jar be pulled from the well bore for adjustment
of the so-called time-regulated devices at the earth's surface, and
then the fishing string and jar must be run back into the well bore
and again connected to the fish, a time consuming and, therefore,
costly operation.
The operation of such jars is time consuming when multiple hammer
blows are to be successively applied to the fish since the bleeding
of the hydraulic fluid through the restricted passage causes a time
delay depending upon the magnitude of the tension which is applied
to the fishing string. In other words, if the tension is low, a
comparatively long period of time is required for the flow of
hydraulic fluid through the restricted passage. If the delay is as
much as 2 to 4 minutes per jarring action and the action is
repeated 500 times, a common occurrence, then the substantial cost
of delivering 500 blows is obvious. On the other hand, where high
jarring forces are desired, the oil flows more rapidly through the
restricted passage as the higher tension is applied to the fishing
string, and under such circumstances, the magnitude of the jarring
blow may be limited by the ability of the pulling rig at the
earth's surface to sufficiently tension the fishing string before
the jar operates to apply the jarring blow.
In essence, such prior hydraulic jars may be characterized as
motion sensitive or motion triggered jars, the time required for
the motion to occur being a function of the applied tension and the
metered flow of the hydraulic fluid through the restricted passage,
so that in any event, even with the use of time regulating
adjustments of the relatively moving parts, there is an inherent
time delay with consequential loss of useful working time. Further
time is lost with conventional jars, when it becomes necessary to
adjust the metering time, either up or down, due to the necessity
of pulling the fishing string and jar from the well bore to effect
the adjustment. Not only does the metering of the hydraulic fluid
through a restricted passage cause a time delay problem, but, in
addition, tremendous heat is generated, prospectively causing seal
failure which would also require pulling the fishing string and jar
from the well bore, as well as reduction in fluid viscosity with
resultant premature tripping. Such heating of the fluid is a
problem that is aggravated when the jar is operated in a hole
containing no liquid to assist in heat dissipation, rendering
certain of the prior art hydraulic jars inoperative in a dry
hole.
In my pending application for U.S. Pat., filed Mar. 15, 1972, Ser.
No. 234,737, now Pat. No. 3,735,827, there is disclosed an improved
down-hole adjustable jar which eliminates the substantial time
delays characteristic of the prior art jars, in that it provides a
load responsive jar which is released to provide the jarring action
responsive to the tension applied to the fishing string. When the
fishing string tension reaches a desired magnitude, the jarring
action is applied. My prior invention obviates the problem of
waiting for the hydraulic fluid to flow through a restricted
passage and also obviates the problem of releasing or jarring
before the desired fishing string tension is reached.
The hydraulic jarring tool of the present invention, like that of
the above-identified application, is one in which the hydraulic
fluid is placed under compression in a compression chamber,
responsive to tension applied to the running or fishing string, and
when the desired tension is reached a normally closed valve is
shifted to its full open position to allow the instantaneous
bleeding off of the compressed hydraulic fluid through a large
bypass flow passage. The valve is opened by a trigger mechanism
which is adjustable with respect to the valve, so that the valve is
triggered open when a predetermined tension has been applied to the
fishing string. Following the operation of the jar, the mere
lowering of the fishing string enables the jar to be reconditioned
for another jarring action.
In order to avoid the necessity of removing the fishing string and
jar from the well bore to adjust or vary the magnitude of the
jarring action, the present invention further provides means
whereby simple manipulation of the fishing string effects
adjustment of the valve trigger mechanism, the jar being capable of
adjustment throughout its entire operable range of jarring force
while in the well, but, as distinguished from my prior jar referred
to above, the present jar has an improved trigger mechanism which
enables the trigger to remain stationary in a selected adjusted
position during jarring operations and to be actuated from its
selected position only when it is to be adjusted.
In accomplishing the foregoing, the invention contemplates
interposing an adjusting ring between the trigger and the cam slot
which effects release of the trigger from one position of
adjustment and its engagement in another adjusted position, the
trigger adjusting ring carrying the cam lug which engages in the
cam slot and having limited freedom of rotation relative to the
trigger to the angular extent necessary to allow the adjusting ring
to follow the cam track during jarring operations without rotating
the trigger on its threaded support while under load. However, when
the trigger is to be adjusted the adjusting ring rotatively drives
the trigger in response to movement of the cam follower lug on the
adjusting ring through the adjusting portion of the cam slot. As a
result of this novel trigger adjusting mechanism the cam follower
lug and the cam slot walls are not subjected to severe loading and
possible damage during the jarring operations.
This invention possesses many other advantages, and has other
purposes which may be made more clearly apparent from a
consideration of a form in which it may be embodied. This form is
shown in the drawings accompanying and forming part of the present
specification. It will now be described in detail, for the purpose
of illustrating the general principles of the invention; but is is
to be understood that such detailed description is not to be taken
in a limiting sense.
Referring to the drawings:
FIGS. 1a through 1e together constitute a longitudinal quarter
section of a jarring tool made in accordance with the invention and
installed in a fishing string, FIGS. 1b through 1e respectively
being successive downward extensions of FIG. 1a, the jarring tool
being shown in a neutral condition;
FIGS. 2a through 2c together constitute a fragmentary, longitudinal
quarter section through portions of the jarring tool, FIGS. 2b and
2c respectively being successive downward extensions of FIG. 2a,
showing the jarring tool in the jarring condition;
FIG. 3 is a horizontal section through the jarring tool, taken on
the line 3--3 of FIG. 1a, showing the splined connection between
the telescopic bodies;
FIG. 4 is a fragmentary horizontal section through the jarring
tool, taken on the line 4--4 of FIG. 1b, showing the connection of
the hammer to the mandrel;
FIG. 5 is a horizontal section through the jarring tool, taken on
the line 5--5 of FIG. 1d, showing the large flow area bypass of the
valve means;
FIG. 6 is a horizontal section through the jarring tool, taken on
the line 6--6 of FIG. 1c, showing the threaded connection between
the trigger and the ratchet sub of the adjustable trigger
mechanism; and showing the connection between the trigger and the
adjusting sleeve for enabling limited free rotation of the
adjusting key.
FIG. 7 is a view corresponding to FIG. 6, but showing the trigger
angularly shifted in the ratchet sub and adjustably connected to
the latter by the ratchet means;
FIG. 8 is a view also corresponding to FIG. 6, but showing the
trigger further angularly shifted from the position of FIG. 7,
180.degree. from the position of FIG. 6, and threadedly connected
to the ratchet sub in another position.
FIG. 9 is a fragmentary longitudinal section, taken on the line
9--9 of FIG. 9, with portions of the trigger mechanism shown in
elevation and in condition for adjustment;
FIG. 10 is a fragmentary detail in section embraced by the circle
10 in FIG. 9 and on an enlarged scale, showing the trigger ratchet
engaged with the ratchet sub;
FIG. 11 is a fragmentary side elevation of the trigger; and
FIG. 12 is a planar developement of the key slot for effecting the
down-hole adjustment of the jar and showing various operating
positions of the companion key.
As seen in the drawings, the down-hole adjustable hydraulic fishing
jar comprises an elongated and telescopic assembly of an inner
elongated tubular mandrel or body 1 and an outer elongated tubular
body or housing 2. At its upper end, the mandrel 1 is provided with
an internally threaded box 3 adapted to receive the externally
threaded pin 4 at the lower end of an upwardly extended section of
drill pipe or drill collar 5, which constitutes a portion of the
running or fishing string S on which the jar is run into a well
bore, and by which the jarring tool is operated to provide a
jarring action for a fishing tool F connected to the lower end of
the body or housing 2. The upper box end 6 of the fishing tool F is
threadedly connected to an externally threaded pin 7 provided at
the lower end of the jar housing 2.
The body 1 comprises an upper tubular body section 8 externally
threaded at 9 to receive the upper internally threaded end 10 of an
intermediate mandrel section 11. The end 10 of the mandrel section
11, below the threads therein, has an internal cylindrical wall 12
adapted to receive an external cylindrical wall 13 at the lower
extremity of the mandrel section 8, and a suitable seal 14 is
interposed between these cylindrical walls 12 and 13. The lower end
of the intermediate mandrel section 11 is threaded at 15 into the
internally threaded end 16 of a lower mandrel section 17, the end
16 of the mandrel section 17 having a cylindrical bore 18 adapted
to receive the lower cylindrical end 19 of the mandrel section 11,
with a suitable seal ring 20 interposed therebetween.
The outer body or housing 2 is shown as comprising an upper tubular
housing section 21 having at its lower end a threaded connection 22
with an externally threaded upper end 23 of an intermediate housing
section 24. The upper end portion 23 of the housing section 24
carries a suitable sealing ring 25 engageable with the inner
cylindrical surface 26 of the housing section 21. At its lower end,
the intermediate housing section 24 is threaded at 27 for
connection with the externally threaded upper end 28 of a lower
housing section and connector sub 29. The upper end 28 of the lower
housing section 29 has a suitable seal ring 30 engaging the
cylindrical inner wall 31 of the intermediate housing 24.
The mandrel 1 and housing 2 are interconnected for relative
longitudinal or telescopic movement, as seen in FIGS. 1a and 3.
More particularly, the upper mandrel section 8 is provided with
external, circumferentially spaced longitudinally extended ribs 32
and grooves 33, and the upper end portion 34 of the housing section
21 is provided with complemental grooves 35 and ribs 36 engaging
with the mandrel section 8 to provide a splined connection. In
order to assure assembly of the housing section 21 on the mandrel
section 8 in a predetermined orientation, the mandrel section 8 has
one rib 37 of greater angular extent than the ribs 32 and the
housing portion 34 has a groove 37a of correspondingly greater
angular extent than the grooves 35 for receiving the rib 37. Such
orientation of the mandrel 1 and housing 2 establishes the
relationship of adjustable trigger means T and the means for
adjusting this trigger, as will be later described.
The end portion 34 of the housing section 21 is relatively massive
and has a lower radial shoulder 38 which constitutes an abutment or
anvil opposed to and adapted to be struck by the opposing radial
shoulder 39 provided by a hammer 40 carried by the mandrel section
8, upon telescopic extension of the bodies 1 and 2. Preferably, the
hammer 40 is detachably applied to the mandrel section 8, as best
seen in FIGS. 1a and 4, by means of a number of threaded,
longitudinally extended and circumferentially spaced ribs 41 on the
mandrel section 8 separated by grooves 42, the threads on the ribs
41 engaging a thread 43 within the hammer 40. The hammer 40 is
fixed in place on the mandrel section 8, by suitable means such as
a set screw 44 threaded into a socket 45 in the mandrel section
8.
Within the space between the body 1 and the housing 2 is a
hydraulic fluid chamber 46 defined between an upper sealing means
47 (FIG. 1b) and a lower sealing means 48 (FIG. 1d). More
specifically, the upper sealing means 47 is provided by a pair of
seal rings 49 confined between the opposing cylindrical walls 50 on
the mandrel section 8 and 51 on the upper end of a trigger
supporting sleeve or ratchet sub 52, hereinafter to be described.
The end portion 52a of the trigger supporting sleeve or ratchet sub
52 has a radially inwardly projecting shoulder 53 against which the
seal rings 49 are held by a gland 54 threaded into the end 52a of
the sleeve 52, so as to effectively seal against very high pressure
when the hydraulic fluid is being compressed in the chamber 46. The
lower sealing means 48 is in the form of an annular, floating
piston 55 reciprocable in the chamber 46 and having inner seal
rings 56 which engage an outer cylindrical wall 57 of the mandrel
section 17 and outer seal rings 58 which engage an inner
cylindrical wall 59 of a sleeve 60, later to be described, which is
disposed in the lower portion of the intermediate housing section
24. This floating piston 55 not only constitutes the lower seal 48
but, also, the piston 55 is a pressure compensating piston which
serves to equalize the pressure in the chamber 46 with the pressure
in the fishing string, since the underside of the piston 55 is
exposed to the pressure present in the running or fishing string S
through the open annular space 61 between the lower mandrel section
17 and the lower body section 29.
Provided within the hydraulic fluid chamber 46 between the upper
seal means 47 and the lower seal means 48 are valved compression
piston means P (FIG. 1d), as well as normally closed by-pass valve
means V (FIG. 1c), and adjustable valve trigger means T (FIGS. 1b
and 1c) which cooperate, as will be later described, in such a
manner that when the fishing tool F is anchored in engagement with
a fish and the mandrel 1 is moved upwardly relative to the housing
2, the transfer of hydraulic fluid within the chamber 46, through
the compression piston means P to the chamber 46 below the piston
means P is shut off and, thereafter, further upward movement of the
mandrel 1 will move the compression piston P upwardly within the
hydraulic fluid chamber 46 to apply compressive force to the
hydraulic fluid between the compression piston means P and the
upper seal means 47, until the hydraulic fluid is compressed to the
extent determined by the tension applied to the running or fishing
string S and by the setting of the trigger means T, which opens the
by-pass valve means V. Opening of the by-pass valve means V enables
the stored energy or tension in the running string S to accellerate
the mandrel 1 upwardly at high velocity to cause the application of
a hammer blow or jarring action of the hammer surface 49 against
the anvil 38. Thereupon, the mandrel 1 may be lowered to its
initial position with respect to the housing 2 and the jarring
action repeated. The time required to effect each jarring action is
determined solely by the time required to tension the fishing
string S to a selected value. Therefore, the tool of the present
invention is capable of effecting a large number of hammer blows or
actions within a relatively short period of time, as compared with
prior jarring tools in which the metering of compressed hydraulic
fluid through a restricted passage is relied upon to sufficiently
deter the jarring action until the desired running string tension
can be accomplished by the pulling rig at the top of the well.
Moreover, the elimination of such conventinal high pressure
metering of compressed hydraulic fluid eliminates the generation of
substantial heat in the fluid, so that the seal life in the present
jar is enhanced. The jar is operable in a dry well bore, as well as
in a well bore containing fluid which assists in the dissipation of
heat.
Referring more particularly to FIG. 1d, the compression piston
means P is shown as comprising an annular piston body 61 slidably
engageable within the cylindrical wall 62 within the intermediate
housing section 24 and having an inside diameter larger than the
outer cylindrical wall 63 of a sleeve 64 on the intermediate
mandrel section 11, so as to provide an annular flow passage 65
betwen the piston 61 and the sleeve 64. About its outer periphery,
the piston 61 has a pair of seal rings 66 disposed between a seat
67 and a ring 68, to be deformed into sealing engagement with the
cylinder wall 62. The sleeve 60, previously referred to, which
provides the cylinder wall 59, has an upper end section 68a
providing a stop shoulder 69 limiting downward movement of the
compression piston 61, the lower end 70 of the sleeve 60 extending
into an annular space 71 defined by the upper end 28 of the lower
housing section 29 and the lower end of the intermediate housing
section 24, a suitable seal ring 72 being interposed between the
end 70 of the sleeve 60 and the end 28 of the housing section 29 to
prevent loss of hydraulic fluid from the chamber 46. The hydraulic
chamber 46 is adapted to be filled with suitable hydraulic fluid
through a filler opening 73 which communicates with an annular
space 74 and radial ports 75 in the upper end 68a of the sleeve 60.
The bleeding of substantially all air from the piston chamber 46 is
enabled by the provision of an outlet port 76, in the
aforementioned trigger support or ratchet sub 52, just below the
upper seal means 47, the port having therein suitable ball plug
means 77 adapted to be forcibly closed by a plug 78, access to the
head of which is provided by a radial slot 79 in the upper housing
section 21, enabling the plug to be manipulated by an appropriate
tool (not shown), but relative angular motion of the ratchet sub 52
and the housing 3 is prevented.
The sleeve 64, which forms the inner cylinder wall 63 for the
compression piston means P, is adapted to be assembled endwise on
the intermediate mandrel section 11 over the threaded lower end of
the latter and retained in place between an upper, downwardly
facing shoulder 80 on the mandrel section 11 and a lower ring 81
which abuts with the upper end of the lower mandrel section 11.
The sleeve 64 slidably supports adjacent its upper end an annular
valve member 82 included in the by-pass valve means V. A coiled
compression spring 83 is interposed between the valve member 82 and
the compression piston 61, to normally bias the valve member 82
upwardly to effect engagement of an annular seating surface 84 on
the valve member 82 with an opposing, complemental annular seating
surface 85 on the intermediate mandrel section 11, which limits
upward movement of the valve member 82. Seal rings 82a are provided
within the lower skirt 82b of the valve member 82 to slidably and
sealingly engage the inner chamber wall 63. The spring 83 also
normally biases the piston 61 downwardly into abutting contact with
the shoulder 69. The intermediate mandrel section just below the
valve seat 85 is provided with an annular groove 86 which
communicates with a number of longitudinally extended grooves 87
(FIG. 5) in the mandrel section 11, these grooves 87 extending
downwardly below the piston 61 when it is in its lowermost
position, and communicating with an inner annular groove 88 in the
ring 81, which has a suitable number of lateral ports 89 spaced
circumferentially thereabout for communication with the chamber 46
above the lower seal means 48. Thus, the annular groove 86 and
longitudinally extending groove 87 in the mandrel section 11,
together with the annular groove 88 and radial ports 89 in the ring
81, provide by-pass flow passsages of substantial flow area through
which hydraulic fluid may transfer from the hydraulic fluid chamber
46 above the compression piston 61, when the valve 82 is off its
seat 85, to the chamber 46 below the compression piston 61.
In order to close off the annular space 65 between the piston 61
and the cylinder wall 63, upon initial upward movement of the
mandrel 1, the sleeve 64 has an enlarged lower end section 90
constituting a valve member having a suitable external seal ring 91
engageable within the compression piston 61, as seen in FIG. 2c.
When the valve portion 90 of the sleeve 64 is within the piston 61,
the ring 81 provides an annular upwardly facing shoulder 92
engageable beneath the piston 61, so that further upward movement
of the mandrel 1 will correspondingly move the piston 61 upwardly,
compressing the hydraulic fluid in the chamber 46 above the piston
61. The greater the compression of the hydraulic fluid, the greater
the force acting on the valve 82 to hold it seated, due to the net
effective differential area of the valve 82 subjected to the
pressurized fluid, the differential area being determined by the
radial extent between the outer end of the seating surface 84 and
surface 63 engaged by the seals 82a.
The extent to which the hydraulic fluid in the chamber 46 between
the compression piston means P and the upper seal means 47 can be
compressed, and, therefore, the tension applicable to the running
or fishing string S, is determined by the space between a lower
abutment surface 93 provided by the trigger means T and the upper
end surface 94 of the valve member 82. The trigger means T is
constructed to position its abutment surface 93 to contact the
valve 82 and unseat the latter, enabling the by-pass of fluid
through the passages 87, the mandrel 1 then rapidly accelerating
upwardly due to stored energy in the running string S. If desired,
a separate accelerating tool (not shown) may be employed to more
rapidly accelerate the mandrel upwardly.
Referring to FIGS. 1b, 1c and 6-11, the adjustable trigger means T
for unseating the valve 82 will now be described. The trigger
supporting sleeve or ratchet sub 52, previously referred to, is
externally threaded into the upper housing section at 52b and a
downwardly extending cylindrical skirt 95 carrying suitable seal
rings 96 engaged with the inner cylindrical wall 26 of the housing
section 21. At the lower extremity of the skirt 95 is a stop ring
97 which seats on the upper end of the intermediate housing section
24, and which will be later described. About the skirt 95, the
ratchet sub 52 is provided with internal ribs, conveniently formed
as an internal thread, such as a square thread 98, of limited
angular extent, say slightly less than 45.degree., as seen in FIG.
6, and in diametrically opposed relation to the thread 98, the
ratchet sub 52 has a similar thread 99 of corresponding limited
angular extent, the thread or rib ends being ramped for a purpose
which will later be described. Between the threads 98 and 99 are
diametrically opposed smooth walled slots 98a and 99a where the
threads 98 and 99 are interrupted. These ribbed or threaded
sections 98 and 99 support the trigger means T which includes a
trigger sleeve 100 adjustable between a lower position with respect
to the ratchet sub 52, as shown in FIG. 1c, at which a pair of
diametrically opposed circumferentially extended stop lugs 101
(only one of which is seen) on the trigger sleeve 100 is engageable
with the stop ring 97 at the lower end of the ratchet sub 52, and
successive positions of adjustment upwardly with respect to rhe
ratchet sub 52. The trigger sleeve 100 consists of an elongated
skirt 102 having circumferentially spaced longitudinally spaced
slots 103 to permit the free flow of hydraulic fluid. At the upper
end of the skirt 102 is a supporting section 104 having
circumferentially spaced external ribbed or threaded sections 105
and 106 and intervening unthreaded sections 105a and 106a, the ribs
or threads of threaded sections 105 and 106 being complemental to
the internal ribs or threads 98 and 99 of the ratchet sub 52 to
connect the trigger sleeve 100 to the ratchet sub 52.
The trigger sleeve 100 also comprises ratchet means engageable with
the thread sections 98 and 99, when the thread sections 105 and 106
are disengaged from the thread sections 98 and 99, to hold the
trigger sleeve 100 in an adjusted axial position with respect to
the ratchet sub 52 until the thread sections 98, 99 and 105, 106
are reengaged. More specifically, the trigger sleeve 100 has
resilient ratchet arms 107 and 108 formed by milling inverted
U-shaped grooves 109 and 110, respectively, in the trigger sleeve
100, at diametrically opposite locations, adjacent to the solid
thread sections 105 and 106. At the upper ends of the resilient
arms 107 and 108 are segments of external ratchet ribs or threads
111 and 112, these ratchet threads being best seen in FIG. 10, in
which the ribs or threads 112 are exemplary. The ratchet threads
112 have a radial, lower surface 112a adapted to engage the upper
surface of the thread 98 and hold against downward movement of the
trigger sleeve 100 with respect to the ratchet sub 52 and housing
2, but upward ratcheting of the trigger sleeve with respect to the
ratchet sub 52 is allowed, due to the downwardly and outwardly
sloped upper surface 112b on the ratchet teeth 112, which cause the
resilient ratchet arms 107 and 108 to be cammed inwardly so that
the ratchet teeth 112 can clear the thread segments 98 and 99.
As previously described, the mandrel 1 and the housing 2 are fixed
in a predetermined orientation by the splined connection provided
by the rib 37 on the upper mandrel section 8 and the longitudinally
extended groove 37a in the upper housing section 21. In order that
the thread segments 98 and 99 in the ratchet sub 52 can be
orientated in a known relationship to the housing 2, these segments
are formed in a predetermined relationship to the cap screw 78
which is disposed in the housing slot 79, as previously described.
Thus, the relative orientation of the thread sections 98 and 99 and
the mandrel 1 is established to enable the angular actuation of the
trigger sleeve 10 by companion key and slot means, herein shown as
including a cam lug or key 115 projecting radially inward from a
trigger adjusting means including a ring 100a carried by the
trigger sleeve 100 and a compound slot 116 formed in the outer
periphery of the upper mandrel section 8, a planar development of
the slot 116 being shown in FIG. 12.
In the illustrative embodiment, as best seen in FIGS. 1c, 2b and 6
through 8, the upper portion 104 of the trigger sleeve 100 has an
internal bore 100b in which the adjusting ring 100a is disposed.
The ring 100a seats on a shoulder 100c, at the base of the bore
100b and is axially confined by a snap ring 100d inserted in a
groove 100e in the trigger sleeve 100. The cam lug or key 115 is
provided on the internal periphery of the ring 100a, and the ring
100a also has an external lug or key 100f which extends outwardly
and into an elongated, axially extended slot 100g in the trigger
sleeve 100. This slot 100g has an angular extent between side walls
100h and 100j which allows limited freedom of relative rotation of
the trigger sleeve 100 and the adjusting means or ring 100a during
jarring operation of the tool, as will be later described, to
relieve the key 115, and the walls of the slot 116 from
loading.
The slot 116 is so formed that relative longitudinal movement
between the mandrel 1 and the housing 2, under the desired
circumstances, will effect angular motion of the trigger sleeve 100
to engage and disengage the thread segments 98 and 99 on the
ratchet sub 52 with the solid or rigid thread segments 105, 106 on
the trigger sleeve 100, or to effect engagement and disengagement
of the ratchet threads 111 and 112 with the thread segments 98 and
99. The slot 116 will also position the sleeve 100 for longitudinal
ratcheting movement of the trigger sleeve 100 upwardly with respect
to the ratchet sub 52, as well as free downward movement of the
trigger sleeve 100 with respect to the ratchet sub 52 when none of
the thread segments 105, 111 or 106, 112 of the trigger sleeve is
engaged with the respective ratchet sub thread segments 98 and
99.
In the latter connection, the ratchet sub 52 includes an internal
radial shoulder 117 against which seats the upper end of a
compression spring 118, the lower end of the spring 118 seating on
the upper end surface 119 of the trigger sleeve 100 to provide a
normal downward bias tending to normally cause the lugs 101 on the
trigger sleeve 100 to engage the stop 97 at the lower end of the
ratchet sub 52.
Referring to FIGS. 6 and 12, it will be seen that the compound slot
116 has a vertically extended upper section 120, the open lower end
of which is opposed by a land 121 having a downwardly inclined
upper end surface 122 leading to an intermediate slot section 123
which also extends vertically. At the base of the slot section 123
is a downwardly inclined surface 124 extending to the left and
leading into a lower vertical slot section 125, the open upper end
of which is opposed by an inclined cam surface 126 which leads back
to the upper vertical slot 120. Extending downwardly in parallel
relation to slot section 125, and opposed at its open upper end by
a cam surface 126, is another vertically extended slot section 127
communicating at its upper end with a downwardly and laterally
extended slot section 128 having a downwardly inclined wall 129.
This wall 129 opposes another upwardly extending slot section 130.
A cam surface 131 leads downwardly and to the left from the slot
section 130 and opposes the open upper end of the slot section
123.
In the embodiment depicted in FIG. 12, it will be understood that
the slot pattern is repetitive at diametrically opposite locations,
so that, as will later be described, the key or pin 115 in one
phase of operation may be at a starting point in the slot 120 at
the 0.degree. marking and in another phase of operation may be at a
starting point in the corresponding slot at the 180.degree. mark.
If desired, diametrically opposite pins or lugs 115 may be employed
on the adjusting ring 100a to engage in the diametrically opposing
and corresponding slot sections.
In the use of a jarring tool with the trigger sleeve 100 in a
starting position, as shown in FIGS. 1a-1e and in FIG. 6, the
running or fishing string S will be elevated thereby causing upward
movement of the mandrel 1 with respect to the housing 2. Therefore,
as seen in FIG. 12, the slot 116 in the mandrel 1 is
correspondingly moved longitudinally with respect to the pin or key
115 to locate the latter in the various operating positions shown
at the locations 1A through 6. However, the angular extent of the
slot 100g in the trigger sleeve 100 is such that movement of the
key 115 from position 1A through slot section 123, into slot
section 125 and back into slot section 120, during jarring
operations, will not cause engagement of the outer key 100f with
either of the side walls 100h and 100j to cause rotative movement
of the trigger sleeve 100.
As the mandrel 1 moves upwardly, the by-pass passages 87 are closed
by the valve member 82 of the valve means V, but fluid is free to
by-pass the compression piston means P through the annular
clearance 65 until the seal 91 above the stop shoulder 92 sealingly
engages within the compression piston 61 and the shoulder 92
engages the piston 61 and moves it upwardly, as upward movement of
the mandrel continues. As upward movement of the compression piston
61 commences, the upper surface 94 of the valve 82 is spaced below
the abutment surface 93 of the trigger sleeve 100 a distance
determined by the relative axial position of the trigger sleeve 100
in the ratchet sub 52, which can be adjusted, as will later be
described, so that more or less compressive force will be applied
to the hydraulic fluid between the compression piston 61 and the
upper seal means 47, allowing more or less energy to be stored in
the fishing string S to create the ultimate jarring blow when the
valve means V is opened. The jarring action can be repeated as
often as desired merely by lowering the fishing string and mandrel
1 to the starting position and then pulling upwardly on the fishing
string, the adjusting ring 100a merely idling or freely moving in
the trigger sleeve 100.
As seen in FIG. 12 when the mandrel 1 is in the lower position, the
indexing lug or key 115 would be in slot section 120 at position
1A. As the mandrel 1 is moved upwardly, the lug 115 will
progressively engage the cam surface 122 and be cammed into slot
section 123. At position 2A, the compression of hydraulic fluid
will commence and, at point 3, the by-pass valve means V will be
opened and the mandrel will then be accelerated upwardly to effect
the jarring action, the indexing lug 115 being cammed by the slot
wall 124 into the slot section 125, and being at position 4A when
the hammer strikes the mandrel to effect the jarring action.
Thereafter, the mandrel 1 may be lowered and the indexing lug 115
will contact the angular wall 126 and thereby be cammed back into
the slot 120 to the point of beginning.
During this relative telescoping of the mandrel and the trigger
during each jarring action, it will be noted that from the starting
point 1A in the slot section 120 until the key 115 is returned to
that point the thread segments 98 and 99 in the ratchet sub 52 will
remain engaged by the solid thread segments 105 and 106 on the
trigger sleeve 100, since the adjusting ring 100a does not transmit
angular motion to the trigger sleeve 100 so that the respective
solid threads remain in continuous full engagement.
When it is desired to adjust the jar apparatus, the position of the
trigger sleeve 100 axially with respect to the ratchet sub 52 is
adjusted in the following manner. The running string S and the
mandrel 1 are elevated, again, until the lug 115 is at the position
2A and the compression piston means P compresses the fluid in the
chamber 46, but the tension applied is less than that required to
unseat the valve 82. The mandrel 1 is then lowered so that the lug
115 will contact the cam surface 131 at the top of the slot section
123 and be cammed to position 5 in the slot 130, and the adjusting
ring lug 100f will engage the slot wall 100h of the trigger sleeve
100 causing angular movement of the latter to a position at which
the trigger sleeve 100 will be released from the ratchet sub 52. In
this connection, it will be noted that the angular distance between
the slot section 120 and the slot section 130 is 45.degree. in the
illustrative embodiment. In the same direction that the trigger
sleeve 100 rotates, that is, in a left-hand rotational direction as
viewed in FIG. 6, the threaded sections 105 and 106 of the trigger
sleeve 100 will shift angularly clear of the thread sections 98 and
99 within the ratchet sub 52, and the trigger sleeve 100 is then
free to move downwardly under the positive bias of the spring 118,
until the stop lug 101 on the trigger sleeve 100 abuts with the
stop means 97. The running string is then again tensioned, moving
the mandrel 1 upwardly, so that the indexing lug 115 will engage
the angular surface 129 at the bottom of slot section 130 and be
moved through slot 128 into slot 127, as indicated at position 6,
thereby causing corresponding angular movement of the trigger
sleeve 100. The angular travel of the trigger sleeve 100 from the
starting position with the lug at 1A to the position 6 is
sufficient to move the trigger sleeve 100 from the position of FIG.
6 to the position of FIG. 8, at which the resilient ratchet arms
107 and 108 are now in longitudinal alignment with the holding
thread sections 98 and 99, respectively, within the ratchet sub 52.
With the ratchet means so aligned, the fishing string is tensioned
to compress the hydraulic fluid in the chamber 46 until the desired
tension has been reached, during the course of which, as seen in
FIG. 9, the valve member 82 will abut with the lower end of the
trigger sleeve 100 and lift the latter progressively, as the
ratchet teeth surfaces 112b cause the ratchet arms 107 and 108 to
be flexed inwardly. When the desired tension is reached to produce
a subsequent jar of the desired magnitude, the fishing string is
again lowered to lower the mandrel 1, the indexing lug 115 moving
from position 6 and being caused to be cammed back to slot 120 by
the cam surface 126, and the adjusting ring causing corresponding
angular movement of the trigger sleeve 100. At this time, the
trigger sleeve 100 will have been rotated a full 180.degree. to the
position relative to the ratchet sub shown in FIG. 8, at which the
holding teeth 98 and 99 within the ratchet sub are engaged by the
solid teeth 106 and 105, respectively, on the trigger sleeve 100.
The trigger sleeve is, therefore, as described above, elevated to a
new position of adjustment which is determined by the magnitude of
the tension applied to the fishing string during the process of the
adjustment.
Each change in the adjustment of the trigger sleeve requires the
same procedure. When the tension is initially applied to the
running string, the trigger sleeve will be located at its lowermost
position with the stop lugs 101 engaged with the stop ring 97.
However, the mandrel need not be moved upwardly to such an extent
that the valve 82 contacts the lower end of the trigger sleeve 100
when the minimum jarring force is desired, the axial position of
the trigger sleeve 100 within the ratchet sub 52 being determined
by engagement of the trigger sleeve stop 101 with the opposing stop
97, at which position the ratchet threads 111 and 112 and the sub
threads 98 and 99 may be out of axial alignment. Proper engagement
of the respective ratchet teeth 111 with a thread section 98 or 99
in the ratchet sub is assured by enabling an increment of free
downward motion of the trigger sleeve after it has been rotated to
align the ratchet teeth with the ratchet sub teeth, so that even if
the ratchet teeth and ratchet sub teeth are confronting one another
and, therefore, are unable to become properly engaged when the
teeth are angularly moved into longitudinal alignment, the trigger
sleeve is permitted to move downwardly under the influence of the
spring 118 until the ratchet threads are fully engaged, as seen in
FIG. 10.
Accordingly, as best seen in FIG. 9, the stop member 97 at the
lower end of the ratchet sub 52, which, as previously indicated, is
in the form of a split ring, has, in the plane of the split,
upwardly opening notches 97a adapted to receive orienting lugs 97b
which depend from the lower end of the ratchet sub 52. The stop
ring 97 has raised portions 97c separated by angularly extended
depressions or recesses 97d adapted to receive the companion stop
part of lug 101 on the sleeve 100. Transition from the recess 97d
to the raised portion 97c is made by means of an inclined cam
surface 97f, which mates with a corresponding cam surface 97 e on
the lower wall of lugs 101. The height of the raised portion with
respect to the recess is at least equal to the pitch of the ratchet
threads 111.
When this apparatus is being adjusted and the pin or cam lug 115 is
in position 5, the trigger sleeve will have moved downward until
lugs 101 contact the bottom of recess 97d. When the mandrel is now
moved upward, the trigger sleeve 100 is rotated as the cam lug 115
moves from position 5 to position 6. This rotation engages the
ratchet teeth 111 with a thread section 98 or 99, and during the
first portion of this movement lifts the trigger sleeve as the lugs
101 are cammed up from the recess surface of the stop ring 97d to
its raised portion 97c. At this time, the ratchet teeth 111 may not
be in perfect axial alignment with threads in section 98 or 99.
However, before rotation ceases, when position 6 is reached, the
lug 101 will pass the end of the raised portion 97c and the trigger
sleeve will be urged downward by spring 118 until the ratchet teeth
are fully engaged, as shown in FIG. 9. The holding thread segments
will also be in correct axial alignment and will mesh without
conflict when the mandrel is lowered and the trigger sleeve rotates
as cam lug 115 progresses from position 6 to position 1.
* * * * *