U.S. patent application number 10/023535 was filed with the patent office on 2003-06-19 for crown block shifting apparatus and method.
Invention is credited to Hebert, Tommy A., Welsh, Walter Thomas.
Application Number | 20030111232 10/023535 |
Document ID | / |
Family ID | 21815688 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030111232 |
Kind Code |
A1 |
Welsh, Walter Thomas ; et
al. |
June 19, 2003 |
Crown block shifting apparatus and method
Abstract
A drilling rig derrick is adapted to direct the hoist lines
reeved between the crown block and the traveling block such that
they enter both in a vertical direction if the traveling block is
moved laterally to clear the work area over the rotary table.
Arrangements are provided to move the crown block laterally, and to
move it back over the rotary table. Alternate provisions displace
the reeved lines with idler sheaves to move the traveling block
only and direct the reeved lines such that they enter both crown
block and traveling block sheaves in a near vertical direction.
Methods for both options are provided.
Inventors: |
Welsh, Walter Thomas;
(Lafayette, LA) ; Hebert, Tommy A.; (New Iberia,
LA) |
Correspondence
Address: |
John D. Jeter
1403 Teche Drive
St. Martinville
LA
70582
US
|
Family ID: |
21815688 |
Appl. No.: |
10/023535 |
Filed: |
December 17, 2001 |
Current U.S.
Class: |
166/379 ;
166/77.51 |
Current CPC
Class: |
E21B 19/02 20130101;
B66D 3/04 20130101 |
Class at
Publication: |
166/379 ;
166/77.51 |
International
Class: |
E21B 019/18 |
Claims
The invention having been described, we claim:
1. Apparatus for moving a crown block of a drilling rig laterally
relative to the vertical centerline of the rotary table to move the
suspended position of the traveling block to one side of the work
area over the rotary table, the apparatus comprising: a) a
distortable derrick capable of responding to an applied distorting
force to move the crown block a preselected distance between a
first position placing a suspended traveling block over the
vertical centerline of the rotary table and a second position
placing the traveling block some horizontal distance from said
vertical centerline of the rotary table; b) forcing means
operatively associated with said derrick to apply said distorting
force.
2. The apparatus of claim 1 wherein said derrick has one portion
hinged relative to the rest of the derrick, said forcing means
arranged to bend the derrick at a selected hinge line.
3. The apparatus of claim 1 wherein said derrick consists of two
portions, a first portion having a generally parallelogram
structure, viewed from either of two opposite sides, with four
hinge centerlines defining flexure points, said forcing means
arranged to move the upper of the parallelogram structure relative
it's lower end.
4. The apparatus of claim 1 wherein said crown block is moved
laterally, relative to the rest of the derrick, between said two
positions.
5. The apparatus of claim 1 wherein idler sheaves engage the reeved
suspension lines between crown block and traveling block, said
idler sheaves arranged to move laterally in response to said
applied distorting force to move the lines such that the suspended
traveling block moves laterally between the work area over the
rotary table and a location some transverse distance from the
vertical centerline of the rotary table.
6. Apparatus for moving the crown block of a drilling rig between a
first position, generally over the centerline of the rotary table,
and a second position some distance to laterally displace the
suspended traveling block, the apparatus comprising: a) a shuttle
carriage to support the crown block; b) a support track mounted on
the rig to support said shuttle carriage and accept movement
between said two positions; and c) force means arranged to apply
force to said carriage relative to said track to move said carriage
between said two positions.
7. The apparatus of claim 6 wherein said shuttle carriage has
wheels arranged to roll on said support track.
8. The apparatus of claim 6 wherein said shuttle carriage has skid
pads arranged to slide on said track.
9. The apparatus of claim 6 wherein said force means is a hydraulic
cylinder.
10. The apparatus of claim 6 wherein said force means is a jack
screw and nut arrangement.
11. The apparatus of claim 6 wherein said force means is a pinion
and rack arrangement.
12. The apparatus of claim 6 wherein said support track is sloped
upward in the direction of displacement from the first position
such that the carriage, when displaced, will move back to the first
position in the absence of a restraining force.
13. The apparatus of claim 6 wherein said movement of said crown
block responds to control means near the rig floor.
14. The apparatus of claim 6 wherein said shuttle carriage is
incorporated into the embodiment of said crown block.
15. Apparatus for moving the crown block of a drilling rig between
a first position, generally over the centerline of the rotary
table, and a second position some lateral distance to align sheaves
of the crown block with the sheaves of a laterally displaced
traveling block, the apparatus comprising: a) a shuttle carriage to
support the crown block; b) a support track mounted on the rig to
support said shuttle carriage and accept movement between said two
positions; and c) force means arranged to apply force to said
carriage relative to said track to move said carriage between said
two positions.
16. The apparatus of claim 15 wherein said shuttle carriage has
wheels arranged to roll on said support track.
17. The apparatus of claim 15 wherein said shuttle carriage has
skid pads arranged to slide on said track.
18. The apparatus of claim 15 wherein said force means is a
hydraulic cylinder.
19. The apparatus of claim 15 wherein said force means is a jack
screw and nut arrangement.
20. The apparatus of claim 15 wherein said force means is a pinion
and rack arrangement.
21. The apparatus of claim 15 wherein said support track is sloped
upward in the direction of displacement from the first position
such that the carriage, when displaced, will move back to the first
position in the absence of a restraining force.
22. The apparatus of claim 15 wherein said movement of said crown
block responds to control means near the rig floor.
23. The apparatus of claim 15 wherein said shuttle carriage is
incorporated into the embodiment of said crown block.
24. Apparatus for moving the crown block of a drilling rig between
a first position, generally over the centerline of the rotary
table, and a second position some lateral distance to reduce the
angle, off vertical, of cables reeved between sheaves of the crown
block and the sheaves of a laterally displaced traveling block, the
apparatus comprising: a) a shuttle carriage arranged to support the
crown block; b) a support track mounted on the rig to support said
shuttle carriage and accept movement between said two positions;
and c) force means to apply force between said track and said
carriage to move said carriage between said two positions.
25. The apparatus of claim 24 wherein said shuttle carriage has
wheels arranged to roll on said support track.
26. The apparatus of claim 24 wherein said shuttle carriage has
skid pads arranged to slide on said track.
27. The apparatus of claim 24 wherein said force means is a
hydraulic cylinder.
28. The apparatus of claim 24 wherein said force means is a jack
screw and nut arrangement.
29. The apparatus of claim 24 wherein said force means is a pinion
and rack arrangement.
30. The apparatus of claim 24 wherein said support track is sloped
upward in the direction of displacement from the first position
such that the carriage, when displaced, will move back to the first
position in the absence of a restraining force.
31. The apparatus of claim 24 wherein said movement of said crown
block responds to control means near the rig floor.
32. The apparatus of claim 24 wherein said shuttle carriage is
incorporated into the embodiment of said crown block.
33. A method for conducting pipe string assembly management
operations on a drilling rig having a crown block, a traveling
block, and cables reeved between crown block sheaves and traveling
block sheaves, and a work area over a rotary table, the method
comprising the steps: a) displacing the traveling block laterally
from the work area over the rotary table; b) moving the crown block
laterally to a location generally over the displaced traveling
block; c) conducting pipe assembly management work over the rotary
table and moving the traveling block to make an upward excursion;
d) moving the crown block back over the rotary table to suspend the
traveling block over the rotary table; and e) suspending the pipe
string upper end from the traveling block and moving the pipe
string axially through the opening of the rotary table.
34. A method for conducting pipe string assembly management
operations on a drilling rig having a crown block, a traveling
block, and cables reeved between crown block sheaves and traveling
block sheaves, and a work area over a rotary table, the method
comprising the steps: a) displacing the crown block laterally from
the work area over the rotary table to displace the traveling block
laterally from the work area over the rotary table; b) conducting
pipe assembly management work over the rotary table and moving the
traveling block to make an upward excursion; c) moving the crown
block back over the rotary table; and d) suspending the pipe string
upper end from the traveling block and moving the pipe string
axially through the opening of the rotary table.
35. The method of claim 34 wherein said pipe assembly management is
related to tripping the pipe string out of the hole.
36. The method of claim 34 wherein said pipe assembly management is
related to tripping the pipe string into the hole.
37. The method of claim 34 wherein said pipe assembly management is
related to tripping the pipe string out of the hole.
38. The method of claim 34 wherein said pipe assembly management is
related to tripping the pipe string into the hole.
Description
[0001] This invention pertains to the main hoisting system of a
drilling rig derrick. More specifically, but not in a limiting
sense, it pertains to means to move the traveling block suspension
lines laterally to suspend the traveling block some lateral
distance from the work area over the rotary table.
BACKGROUND OF INVENTION
[0002] By conventional practice, the traveling block of the main
hoisting system of a drilling rig has been employed in most
vertical movement of the pipe string. An assembled pipe string may
weigh in the order of five hundred tons and that is appropriate use
of the main hoisting system. The main system, however, has been
used to handle single sections of pipe. New pipe sections are
within the weight handling capacity of secondary lifting gear.
Lighter handling means were not usable in the past, to add pipe
sections to the pipe string, because the traveling block occupied
the traffic path above the rotary table.
[0003] The assembled pipe string was supported, along the well
center line, in a spider near the derrick floor. The traveling
block was moved upward in the derrick, lifting the new section to a
position for its lower end to be connected to the pipe string in
the spider. The large lifting system was involved in handling a
light weight load. That was inefficient use of massive and slow
hoisting equipment.
[0004] New systems have been installed to handle the pipe section
while the slower traveling block is being raised to address the top
of the new section. Activities related to connecting the new
section to the pipe string can be underway while the traveling
block is engaged in the upward excursion. When the traveling block
reaches the required position, the lighter section handling gear is
moved away to allow the traveling block to lower the pipe string.
The enabling factor has been side shifting arrangements to pull the
traveling block toward the side of the derrick to clear the well
centerline above the rotary table for the new section handling
gear. The side shifting system is trolley-mounted to accommodate
the upwardly moving traveling block. Under those displaced
conditions the traveling block is not used to lift significant
loads.
[0005] Early drilling rigs were used such that the draw works was
opposite the vee door, giving the driller the best possible view of
activities. When the traveling block was used to lift loads
entering the vee door it was practical to orient the crown block
with the sheave axes transverse to the vee door, parallel to the
axis of the cable drum, so that displacement of the traveling block
toward the vee door caused the least damage to reeved cables
entering the crown block sheaves.
[0006] The evolution of the main hoisting gear in the derrick has
resulted in some changes in the early relationships between the
draw works cable drum but the changes have not been severe.
Ancillary gear related to the hoist system has crowded the drilling
floor such that the newly added ability to shift the traveling
block, to clear the work area over the rotary table, may be done in
a direction along the axis of rotation of the cable sheaves in both
the crown block and traveling block. That causes the cables to be
skewed when entering and leaving the sheaves if the traveling block
alone is laterally displaced. The traveling block can be moved only
a limited distance toward the crown block, increasing the angle of
misalignment, before the cables begin to chafe unacceptably on the
sheaves. In such cases the height to which the traveling block can
be raised is less than that possible if the traveling block is
directly below the crown block, or the lines routed to move
vertically to and from both the crown block and traveling block.
The difference is wasted pipe handling capacity.
[0007] The hoisting cable is wound on the cable drum of the
drawworks, extends as a live line to the crown block through
intermediate sheaves, is reeved about twelve times between crown
block and traveling block, extends down as a dead line from the
crown block, extends through a clamp, and extends on, to a reserve
cable storage reel. As cable wears in the sheaves, more line is
occasionally run off the reserve reel, along the routes cited
above, and a length is cut off the end anchored to the draw works
cable drum. Economics of the matter will not tolerate running a
misaligned traveling block too near the crown block, with the
resulting chafing of the cable.
[0008] The excess distance below the crown block at which the
traveling block is stopped is wasted derrick space. The economics
of that wasted derrick space makes the new handling system less
attractive than it would be if the traveling block could be raised
higher each trip. Otherwise stated, if the traveling block can be
moved higher, a longer new pipe length can be added to the pipe
string each trip made by the traveling block. That is economically
beneficial because a rig can complete a well in less time. The rig
time is expensive and the petroleum is becoming a more critical
industrial necessity.
SUMMARY OF THE INVENTION
[0009] Therefore, it is an object of this invention to provide
apparatus to direct the reeved suspension lines vertically into and
out of the crown block and traveling block when the traveling block
is laterally displaced.
[0010] It is another object of this invention to provide apparatus
to move the crown block of a drilling rig laterally to suspend the
traveling block to one side of the rotary table centerline to clear
the work area over the rotary table to permit activity above the
rotary table not requiring the traveling block.
[0011] It is yet another object to provide reeved suspension lines
with side loading idler sheaves arranged to move the lines
laterally, and return them to the un-displaced state to move the
traveling block laterally relative to the centerline of the rotary
table.
[0012] To achieve the objectives, provisions near the top of a
derrick, move the crown block laterally to suspend the traveling
block clear of the work area over the rotary table. It also moves
the crown block back to center the traveling block over the rotary
table. Otherwise stated, provisions to move the crown block
laterally permits the traveling block to be raised while clear of
the work area over the rotary table and moves the crown block, and
traveling block, back over the rotary table to make a downward
excursion with a pipe string load. Such movement allows lighter
pipe handling gear to erect a stand of pipe over the pipe string
suspended from a spider for connecting the new section to the pipe
string while the traveling block makes its upward excursion.
[0013] If the traveling block is stabilized by means to control its
upward movement when displaced laterally, the movement of the crown
block keeps the sheaves in the crown block and the sheaves in the
traveling block acceptably aligned to avoid chafing cables reeved
about sheaves of both blocks.
[0014] Three options are disclosed for moving the traveling block
laterally. One concept distorts the derrick to move the crown block
laterally, and consequently moves the suspended traveling block
laterally. A second concept distorts the normal path of the reeved
lines between crown block and traveling block to leave the crown
block in place and move the suspended traveling block. The
preferred concept for lateral displacement moves the crown block
laterally relative to the derrick, to move the suspended traveling
block laterally. All concepts can work well with systems that force
the traveling block laterally by aligning the reeved lines with the
related sheaves.
[0015] In the preferred form, a shuttle carriage equipped with
either skid means or roller means moves along a carriage way on the
derrick to laterally transport the crown block. Movement of the
shuttle is powered by force delivery means, preferably at least one
hydraulic cylinder. Jack screws or gear-and-rack moving means are
typical of equivalent alternatives. To assure reliable function, a
combination of carriage-moving contrivances can be used.
[0016] When conditions permit, idler sheaves are situated in the
derrick and arranged to move the reeved suspension lines laterally
just below the crown block to displace the lines such that the
traveling block is suspended a selected distance from the
centerline of the rotary table. Moving the idler sheaves back to a
neutral position then positions the traveling block over the rotary
table centerline. Two sets of sheaves are usually needed for the
lateral displacement function and they are preferably all carried
on one shuttle fixture secured to the derrick. A third set of
sheaves can be used to favorably route the reeved lines downward
from the crown block.
[0017] Alternative arrangements distort the derrick by tilting the
top of the derrick to displace the crown block relative to the
rotary table. In one embodiment the top of the derrick is rigid and
hinged in one side. Lifting gear, preferably hydraulic cylinders,
lift the side of the derrick opposite the hinges.
[0018] A second tilting arrangement does not separate derrick legs
but skews two sides of a parallelogram derrick section to displace
the crown block relative to the rotary table.
[0019] These and other objects, advantages, and features of this
invention will be apparent to those skilled in the art from a
consideration of this specification, including the attached claims
and appended drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0020] In the drawings, similar captions refer to similar
features.
[0021] FIG. 1 is a side view of a prior art representative derrick
and associated hoisting equipment.
[0022] FIG. 2 is a side view similar to FIG. 1, also prior art,
with a traveling block moved laterally to clear the work area over
the rotary table.
[0023] FIG. 3 is a side view of the novel arrangement to move both
crown block and the traveling block clear of the work area over the
rotary table.
[0024] FIG. 4 is a side view of the novel arrangement with the
crown block of FIG. 3 moved back over the rotary table.
[0025] FIG. 5 is an elevation of a crown block shifting assembly,
partly cut away, viewed perpendicularly to the sheave axes.
[0026] FIG. 6 is a sectional view taken along line 6-6 of FIG.
5.
[0027] FIG. 7 is a view from the aspect of FIG. 6 but with rollers
instead of skids.
[0028] FIG. 8 shows line and sheave arrangements for rerouting
reeved lines.
[0029] FIG. 9 is identical to FIG. 8, with rerouting displacement
of lines.
[0030] FIG. 10 is an end view of the shuttle arrangement for FIGS.
8 and 9.
[0031] FIG. 11 is identical to FIG. 9, with an extra routing
sheave.
[0032] FIG. 12 is a side view of a distortable derrick.
[0033] FIG. 13 is a side view of the distortable derrick in the
tilted position.
[0034] FIG. 14 is a side view of an alternate form of distortable
derrick, in the straight configuration.
[0035] FIG. 15 is identical to FIG. 14, with the derrick top
skewed.
DETAILED DESCRIPTION OF DRAWINGS
[0036] FIG. 1 shows representative derrick 1 supporting crown block
5 with sheaves 10 suspending traveling block 4, on upper structure
11, and elevator 3 by cables 8 reeved about sheaves 9 supporting
pipe string P which extends through rotary table 2. This is prior
art.
[0037] FIG. 2 has the same situation as FIG. 1, represents prior
art, but the traveling block has lowered the pipe string P, now
supported by spider 2. The connector, or collar, 14 is situated at
a working height above base structure 15. The traveling block has
been moved to one side by trolley means 12 which is capable of
moving vertically along track 13. When the traveling block moves
higher, the cables 8 are skewed at an increasing angle. Cables 8
are chafed by the entry and exit angles relative to sheaves 9 in
the traveling block and sheaves 10 in the crown block. The lateral
movement of the traveling block is done to clear the work area over
the rotary table to permit manipulator 7, of varied forms and
choices, to position a new section S of pipe for attachment to the
pipe string suspended in the spider 2. This process is prior art
and permits the positioning and connection of the new pipe section
while the slow traveling block makes the upward excursion. Pipe
tongs are often present near the rotary table but are not
shown.
[0038] FIG. 3 shows the same derrick 1 but the crown block 5 is
moved laterally by a carriage (shown in detail by FIGS. 5 and 6)
which moves along a carriage way, or track, (see FIGS. 5 and 6) on
the modified upper structure 11A to place the crown block over the
laterally displaced traveling block.
[0039] FIG. 4 shows the crown block moved back over the rotary
table to position the traveling block in alignment with the rotary
table, and the pipe string centerline, in preparation for lowering
the assembled pipe string into the well. Elevator 3 is not yet
attached to the pipe string. Normally, the elevator will be
connected to the pipe string before the manipulator 7 releases the
new pipe stand S. The elevator will lift the pipe string and the
spider will release the pipe string when it is supported by the
elevator.
[0040] In FIGS. 5 and 6 the major derrick upper structure 11A is
fitted with slideways 24 to allow the crown block mounted on skids
23 to move laterally. Movement is forced by hydraulic cylinders 21
mounted on structure 20 to act against structure 22 to move the
crown block an amount set by the travel limiter 25. The space below
the crown block, between cables 8, is unobstructed. At times the
crown block is lowered through that opening for maintenance. The
hydraulic cylinders will normally be connected to hydraulic
plumbing (not shown) that lead to a power source and controls near
the rig floor.
[0041] FIG. 7 is a fragmented view from the aspect of FIG. 6 but
showing rollers 31 rolling inmodified track 30 on the modified
crown block carriage 32. Wheels on axles are shown but commercially
available and equivalent circulating rollers can carry an elongated
bearing plate along the same roller way. Such load carrying
contrivances are well known to those skilled in the art of machine
construction.
[0042] FIG. 8 is devoid of derrick structure not needed in
disclosing points of novelty. Crown block sheave 50 is carried by
derrick mounted support 51. Reeved suspension lines 58 support
traveling block sheave 57. That configuration leaves the hook line
of movement HLM coincident with the well center line WCL. Just
below the crown block, attached to the derrick, shuttle tracks 60
carry shuttle 54 which carries idler sheaves 56 and 55. The shuttle
is moved laterally by hydraulic cylinder 53 which is secured to the
derrick by bracket 52.
[0043] In FIG. 9, with no shuttle or tracks shown, sheaves 56 and
55 are shown to have moved the reeved lines 58 laterally to place
the traveling block such that the hook moves along line HLM some
distance from the well center line WCL.
[0044] Note that the portion 58a of the reeved lines 58 depart the
crown block at a large angle relative to vertical. Not all derrick
geometry will accept such line configuration. The arrangement of
FIG. 11 results.
[0045] In FIG. 11, idler sheave 61, supported by the derrick by way
of bracket 60 minimizes the derrick section plan form area required
to accept the lines. The balance of FIG. 11 is much the same as
FIG. 9.
[0046] FIG. 10 is an end view of the shuttle track 60, taken along
line 10-10 of FIG. 8. Tracks 60 are secured to the derrick. Shuttle
54 carries four wheels, two shown as 55a and 55b, which run in the
channel of beams 60. Shuttle 54 also carries sheaves 55 and 56 (56
shown) which engage the reeved lines 58 to accomplish the line
configuration of FIG. 9 or 10.
[0047] Well drilling sites are well known for unexpected conditions
which disable peripheral hydraulic systems, and other powered
apparatus. Often, it is important in such cases to have the main
hoisting gear operational in the conventional manner over the well
centerline. On the preferred embodiment, the roller way 24 can be
constructed with an upward slope toward the right end viewed from
the aspect of FIG. 5. The crown block would be level but would rise
during the rightward excursion. In case of hydraulic failure when
the crown block is in the rightwardly displaced position, the
hydraulic system could be vented of restraining fluid and the crown
block would roll to the left back to the leftward position. The rig
hoisting gear could then be used in the conventional manner until
the problem is corrected.
[0048] The apparatus of FIGS. 8, 9, and 11 are naturally self
restoring in that they tend to return to the configuration that
leaves the traveling block over the rotary table, unless they are
restrained in the traveling block displacing state. The
self-restoring ability is anticipated by and is within the scope of
the claims.
[0049] Hydraulic shifting cylinders are currently preferred for
moving the crown block but other equivalent means of forcing
movement can be used. Powered lead screws and rack and pinion
moving means are well established in the art of machine
construction and may be used instead of hydraulic cylinders. Such
construction is anticipated by and is within the scope of the
claims.
[0050] It is common practice in rig operations to use cable sheaves
just above the draw works to assist in level winding of cable onto
the cable drum. Other guide sheaves are situated in the derrick to
define the path of the dead line and to aid in control of the live,
or fast, line between the cable drum and the crown block sheaves.
Positioning and management of those intermediate sheaves differ
with different drilling rigs. Choices of such varied arrangements
are anticipated by the claims. Such choices are well established in
the art of derrick rigging and their omission from the claims is
not to be construed in a limiting sense. Any anticipated choices
for intermediate sheave usage may be used with the apparatus of
this invention.
[0051] FIGS. 12 and 13 show two upper portions 70 and 71 of a
derrick having hinge line 76 along one side and power tilt means 75
on the opposite side. When the power tilt means, shown as a
hydraulic cylinder, is extended, the upper portion tilts about
hinge line 76 to place the crown block 72 some distance from the
original position. Traveling block 73 is then suspended to move
along vertical line HLM. That is some lateral distance from the
original line of vertical lift WCL. If necessary, draining fluid
from the cylinder 75 will cause the derrick to correct to the
symmetrical arrangement of FIG. 12.
[0052] FIGS. 14 and 15 show a derrick arrangement is which portion
80 could be the derrick base structure or a higher structure in the
derrick. Crown block 72, traveling block 73, lines of motion WCL
and HLM, are the same as those in FIGS. 12 and 13. Lateral movement
of the crown block results from skewing derrick structure rather
than lifting one side. There are four hinge lines that allow sides
81a and 82a to tilt but remain parallel. That holds structure 84
level, or in the original attitude but moved laterally. Power
skewing motor 83, preferably a pair of hydraulic cylinders, operate
against side 81a to control the skew and the skew correction. There
are several possible equivalent lines of action for the skewing
motor. Sides 81a and 82a, viewed from the side relative to the
plane of the drawing, can be tapered or rectangular.
[0053] Oil field rigging art is old and well established. The
apparatus of this invention will be used on derricks of many
different configurations. Those skilled in the art will have no
problem adapting the points of novelty presented herein to the many
different derrick structures to be encountered.
[0054] From the foregoing, it will be seen that this invention is
one well adapted to attain all of the ends and objects hereinabove
set forth, together with other advantages which are obvious and
which are inherent to the apparatus.
[0055] It will be understood that certain features and
sub-combinations are of utility and may be employed without
reference to other features and sub-combinations. This is
contemplated by and is within the scope of the claims.
[0056] As many possible embodiments may be made of the apparatus of
this invention without departing from the scope thereof, it is to
be understood that all matter herein set forth or shown in the
accompanying drawings is to be interpreted as illustrative and not
in a limiting sense.
* * * * *