Pipe tapping

A pipe tapping device which includes a valve conduit having a longitudinal axis, a fluid inlet portion and a fluid outlet portion, wherein the fluid inlet portion has associated therewith, a cutting edge; mounting apparatus for mounting the valve conduit onto a pipe to be tapped; and compression apparatus for bringing the cutting edge into compressive contact with an outer surface of the pipe prior to tapping of the pipe; wherein the valve conduit is selectably rotatable about the longitudinal axis, such that upon bringing the cutting edge into the compressive contact with an outer surface of the pipe, rotation of the valve conduit is operative to transfer a turning force to the cutting edge so as to cause the cutting edge to cut a preselected portion of the pipe wall, thereby to form a coupon.

FIELD OF THE INVENTION 
The present invention relates to pipe tapping apparatus used for attaching 
branch fittings to pipelines--including pipelines used for transporting 
pressurized or high temperature substances--without disrupting the flow 
therethrough. 
BACKGROUND OF THE INVENTION 
Pipe tapping devices are commonly recognized for the important role which 
they play in overcoming the need to shut down the operation of pipeline 
systems in order to join or repair branch fittings. Although the 
individual design of pipe tapping apparatus may differ amongst various 
devices disclosed by prior known art, the common function of such 
apparatus is to allow for the joining of new branch fittings without 
disruption to the through-flow of fluid in the main pipe. 
Some disadvantages which are commonly presented by known pipe tapping 
devices include: 
i) large dimensions and complexity of the apparatus used, which in turn, 
often result in increased production costs; 
ii) difficulties associated with overcoming resistive forces where a large 
area of pipe wall is sought to be tapped; 
iii) difficulties associated with tapping thick pipe walls, or pipes made 
of very hard materials; 
iv) the time taken to install and remove pipe tapping apparatus; 
v) the long-term stability of the branch fitting tapped into a pipe, 
especially around the joint between the branch fitting and the main pipe; 
vi) difficulties associated with removal of the `coupon` or `slug` portion 
cut from the pipe. 
An indication of the state of the art is provided by European Patent 
Application EP 0,754,900 A1, entitled "Tapping Fitting", which discloses a 
tapping tee fitting for application to a pipe in order to tap a fluid 
conducted therethrough to an ancillary device. The tapping fitting 
includes a housing having a rotatable blade assembly which is threadedly 
received within the housing main section, and includes a cylindrical 
cutting blade at its inner end which may be employed to cut a cylindrical 
slug from the pipe. The device further includes a hollow stem secured to 
the rotatable assembly. An outlet section is positioned generally 
transversely to the housing main section so that it rests generally above 
and perpendicular to the area of the pipe which is sought to be tapped. In 
operation, a key is used to rotate the hollow stem and blade assembly from 
an initial retracted position to a projected position which represents 
completion of the cutting operation. Thereafter, the cutter blade assembly 
is rotated in the opposite direction within the hollow stem so as to 
retract the cutter assembly from its engagement with the pipe. The key may 
then be removed and the hollow stem is detached so as to leave the cutter 
assembly retained in the housing main section. 
Whilst the above device describes a comprehensive tapping fitting for use 
in tapping a fluid through to an ancillary device, the threaded nature of 
the rotatable blade assembly and the cylindrical cutting blade, would 
appear to compound the resistive forces which arise during the cutting 
process, thereby limiting the usefulness of the device in respect of pipes 
which feature large diameters, thick pipe walls, and/or materials 
difficult to penetrate. 
SUMMARY OF THE INVENTION 
It is an aim of the present invention to provide a pipe tapping device for 
attaching branch fittings to pipelines, including pipelines in operation, 
which overcomes disadvantages of known art. 
There is thus provided, in accordance with a preferred embodiment of the 
invention, a pipe tapping device which includes: 
a valve conduit having a longitudinal axis, a fluid inlet portion and a 
fluid outlet portion, wherein the fluid inlet portion has associated 
therewith, a cutting edge; 
mounting apparatus for mounting the valve conduit onto a pipe to be tapped; 
and 
compression apparatus for bringing the cutting edge into compressive 
contact with an outer surface of the pipe prior to tapping of the pipe; 
wherein the valve conduit is selectably rotatable about the longitudinal 
axis, such that upon bringing the cutting edge into the compressive 
contact with an outer surface of the pipe, rotation of the valve conduit 
is operative to transfer a turning force to the cutting edge so as to 
cause the cutting edge to cut a preselected portion of the pipe wall, 
thereby to form a coupon. 
Additionally, in accordance with a preferred embodiment of the present 
invention, there is also included apparatus for extracting the coupon from 
the pipe wall. 
Further, in accordance with a preferred embodiment of the present 
invention, the compression apparatus also includes a rotatable compression 
element mounted for rotation about the valve conduit. 
Preferably, in accordance with a preferred embodiment of the present 
invention, the compression element is mounted onto at least a portion of 
the mounting apparatus extending transversely to the pipe wall, and 
arranged for selectable rotation about the portion of the mounting 
apparatus so as to axially translate therealong when rotated. 
Additionally, in accordance with a preferred embodiment of the present 
invention, the compression apparatus also includes a compressive resilient 
element, arranged between the compression element and a predetermined 
support portion of the valve conduit, and the compression element is 
operable to be rotated in a predetermined direction about the longitudinal 
axis so as to compress the resilient element. 
Further, in accordance with a preferred embodiment of the present 
invention, compression of the resilient element causes transfer of an 
axial force to the cutting edge via the support portion of the valve 
conduit, so as to cause the cutting edge to bear on the pipe wall. 
Additionally, in accordance with a preferred embodiment of the present 
invention, the apparatus for extracting the coupon from the pipe wall 
includes apparatus for retracting the coupon through the valve conduit to 
the outlet portion. 
Further, in accordance with a preferred embodiment of the present 
invention, the apparatus for retracting the coupon through the valve 
conduit to the outlet portion includes a gripping device having a gripping 
rod axially extending through the valve conduit, wherein the gripping rod 
is preferably selectably rotatable and includes an end bit for threaded 
engagement with the preselected portion of the pipe wall from which the 
coupon is to be formed. 
Additionally, in accordance with a preferred embodiment of the present 
invention, the gripping device and the compression apparatus cooperate to 
bring the end bit into compressive contact with an outer surface of the 
pipe. 
Further, in accordance with a preferred embodiment of the present 
invention, there is also included apparatus for selectably closing the 
fluid outlet portion to through-flow which preferably includes a valve 
mechanism. 
Additionally, in accordance with a preferred embodiment of the present 
invention, there are also included one or more sealing elements for 
sealing between the fluid inlet portion of the valve conduit and the 
mounting apparatus, one or more sealing elements for sealing between the 
mounting apparatus and the pipe, and one or more sealing elements for 
sealing the fluid outlet portion of the valve conduit. 
Further, in accordance with a preferred embodiment of the present 
invention, the outlet portion of the valve conduit is configured for 
attachment of a branch member thereto. 
There is also provided in accordance with an additional preferred 
embodiment of the invention, a method of tapping a pipe which includes the 
following steps: 
mounting onto a pipe to be tapped a valve conduit having a longitudinal 
axis, a fluid inlet, a fluid outlet, and a cutting edge associated with 
the inlet, wherein the cutting edge is arranged adjacent to the pipe; 
compressing a compressive resilient element so as to cause the cutting edge 
to bear onto a portion of a wall of the pipe sought to be tapped; and 
rotating at least the valve conduit about the longitudinal axis, so as to 
cause a rotation of the cutting edge relative to the pipe, thereby causing 
the cutting edge to cut through the pipe wall so as to form a coupon. 
Further, in accordance with the additional preferred embodiment of the 
present invention, the method also includes the following additional 
steps: 
prior to formation of the coupon, gripping the portion of the pipe wall 
from which the coupon is formed, and 
removing the coupon from the pipe. 
Additionally, in accordance with the additional preferred embodiment of the 
present invention, the step of removing the coupon from the pipe includes 
the step of extracting the coupon through the valve conduit. 
Optionally, in accordance with the additional preferred embodiment of the 
present invention, the steps of compressing the compressive resilient 
element and rotating at least the valve conduit about the longitudinal 
axis, are alternatingly repeated until the cutting edge cuts through the 
entire thickness of the pipe wall. 
Further, in accordance with the additional preferred embodiment of the 
present invention, the step of gripping includes the following sub-steps: 
positioning a threaded gripping element adjacent to the portion of the pipe 
wall from which the coupon is formed; 
compressing the compressive resilient element so as to cause the threaded 
gripping element to bear onto the portion of pipe wall; and 
rotating the threaded gripping element thereby causing the threaded 
gripping element to threadedly engage the portion of the pipe wall. 
Optionally, in accordance with the additional preferred embodiment of the 
present invention, the sub-steps of compressing the compressive resilient 
element and rotating the threaded gripping element, are alternatingly 
repeated until such time as the threaded gripping element engages the 
portion of the pipe wall to at least a desired depth. 
Additionally, in accordance with the additional preferred embodiment of the 
present invention, the method also includes the step of closing the fluid 
outlet to through-flow of fluid prior to cutting through the pipe wall.

DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates to the provision of pipe tapping apparatus 
which may be used for example, to attach a branch device to a main 
pipeline without disconnecting or interrupting the flow through the main 
pipeline. The apparatus may be utilized for tapping a variety of 
pipelines, including pipelines which carry pressurized gas or liquid 
materials. 
By way of non-limiting example, the apparatus may be used for connecting 
branch members to an existing pipeline. Alternatively, the apparatus may 
be used to attach by-pass pipeline branches to a main pipeline, so as to 
make possible the reconditioning or repair of a section of the main 
pipeline without interrupting the use thereof. Similarly, the present 
invention may be employed to insert an outlet channel or outlet tap into a 
pipeline for use in connecting removable appliances, such as pipeline 
testing devices. 
Whilst the description set out hereinbelow describes a pipe tapping device 
which is constructed for use in tapping pipelines in operation, the 
present invention is also intended to be adaptable for use in repeated 
hole drilling of pipes not under pressure at the time of tappping. 
Referring generally to FIGS. 1-6, there is seen a pipe tapping device, 
referenced 10, constructed and arranged in accordance with a preferred 
embodiment of the invention, and attached to a pipe P. Typically, pipe 
tapping device 10 includes four main components, namely: a mounting 20, a 
tapping valve 30, compression apparatus 40, and apparatus for extracting a 
detached portion of pipe shown in FIGS. 5 and 6 as coupon, C, once it has 
been cut from a pipe wall. Such apparatus may be exemplified by a gripping 
device, referenced 50. 
Referring now to FIG. 1 in more detail, mounting 20 of pipe tapping device 
10 is seen to be typically formed of two rigid complimentary mounting 
portions 21 and 22, each mounting portion being configured for placement 
around a semi-cylindrical, outer surface portion of pipe P as illustrated. 
Once mounted onto pipe P, mounting portions 21 and 22 are held together by 
suitable fastening elements 23 which may take the form of threaded 
securing bolts as illustrated, or other mechanical securing apparatus such 
as fastening clamps and the like (not shown). 
Integrally formed with mounting portion 22 of mounting 20, is a cylindrical 
connector 24 which is oriented generally transverse to pipe P. Preferably, 
connector 24 has formed thereon, an outward-facing thread 25 along at 
least a portion of its outer surface 26. Connector 24 is further formed so 
as to receive therein, a conduit portion of valve 30, hereinafter 
referenced valve conduit 31. Typically, valve conduit 31 is formed of any 
suitable metal or rigid plastic. 
A sealing element 70 is also provided in conjunction with mounting 20, so 
as to prevent the escape of fluid through the interface formed between 
mounting portion 22 and the pipe wall, after pipe P has been tapped (FIGS. 
5 and 6). 
Referring still to FIG. 1, valve conduit 31 is seen to have an inlet 
portion 32 and an outlet portion 36. Valve conduit 31 also incorporates a 
support portion 37, which serves as an interface between valve 30 and 
compression apparatus 40. As illustrated in FIGS. 1-6, support portion 37 
may take the form of an annular flange. 
Also included in valve 30, is a valve mechanism 38, which is provided 
upstream of outlet portion 36. Valve mechanism 38 typically includes a 
handle 38a and a valve element 38b, and is operative to selectably close 
valve 30 to through-flow of a fluid as and when required. Located 
downstream of valve mechanism 38, is an end cap 39 which is threadedly 
attached to outlet portion 36 of conduit 31. 
Considering now inlet portion 32 of valve conduit 31 in more detail, there 
is seen an annular cutting edge, referenced 33, which is operable to cut 
cylindrical coupon C (FIGS. 5 and 6), from pipe P. As illustrated in FIG. 
1, cutting edge 33 may be provided via a separately formed cutting element 
34, which is securely affixed to an end 32a of inlet portion 32 by means 
of welding or other suitable methods of attachment. Alternatively, cutting 
edge 33 may be integrally formed with inlet end 32a of valve conduit 31 
(not shown) thereby obviating the need for securing a separately formed 
cutting element to the valve conduit. 
Referring now also to FIG. 1A, there is seen a sealing element 35a and a 
spacer ring 35b, positioned between an inner shoulder 24a (FIG. 1) of 
connector 24 and inlet end 32a of valve conduit 31. Sealing element 35a is 
typically formed as a sealing ring, and functions to seal between conduit 
31 and connector 24 when the conduit and connector are brought into full 
mating engagement (FIGS. 5 and 6). Spacer ring 35b is made of any suitable 
low-friction plastic or metal, which, when pressed into contact with inlet 
end 32a during operation of device 10, allows for the rotation of conduit 
31 with a minimum degree of friction or resistance between itself and the 
conduit. Additionally, spacer ring 35b is used to limit the extent to 
which cutting edge 33, and associated cutting element 34 or inlet portion 
32 (as the case may be), may enter pipe P upon the cutting of coupon C. 
Turning now to the third main component of pipe tapping device 10, 
compression apparatus 40 is typically formed of a compression nut 41, 
which in the illustrated example, is arranged to fit over a portion of 
conduit 31 and to threadedly engage connector 24 by means of an 
inward-facing thread 42. Further, a compressive resilient element 45, 
shown herein as a compressive spring, is disposed within compression nut 
41 between support portion 37 and an end bearing portion 46. It will be 
appreciated that a rotation of compression nut 41 in a direction 
predetermined to cause an axial translation thereof relative to connector 
24, is operative to compress resilient element 45, so as to apply an axial 
force to support portion 37. As will be understood from the description 
below, such an axial force is used to assist in the attachment of gripping 
device 50 to pipe P. Similarly, in the preferably subsequent cutting 
process wherein coupon C is cut from pipe P, a similar such axial force 
arising from the compression of resilient element 45, is applied to 
support portion 37 and transferred to cutting edge 33, so as to assist in 
the penetration and cutting of the pipe. 
Gripping device 50 preferably includes an axially extending rod 52, having 
an end bit 53 which has formed thereon, an external thread 54 arranged for 
gripping a portion of pipe to be cut, so as to enable removal thereof 
after cutting. As is seen in FIG. 1, rod 52 axially extends through valve 
conduit 31 and end cap 39 upon assembly of pipe tapping device 10. Rod 52 
also has formed thereon, an end located threaded portion 52a (FIG. 1B) 
onto which an end nut 56 is seen to be mounted. Further, a locking element 
39a such as a screw, arranged for projection into a circumferential 
channel 39b formed on a portion 52b of rod 52, is operative to limit an 
axial displacement between rod 52 and the remainder of pipe tapping device 
10 (FIG. 1B). A relative rotation therebetween, is however permitted. 
The operation of pipe tapping device 10 in performing the method of the 
invention after mounting 20 has been securely affixed to pipe P, is now 
described in conjunction with FIGS. 1-7. 
Referring once again to FIGS. 1-1B, pipe tapping device 10 is seen to be 
mounted to pipe P by means of mounting 20, prior to commencement of the 
pipe tapping operation. As seen in FIG. 1, inlet portion 32 of valve 
conduit 31 is sufficiently inserted into connector 24 so that conduit 31 
lies in a generally coaxial alignment with connector 24. At the same time, 
compression nut 41 is threadedly engaged with an end portion 24b of 
connector 24, allowing resilient element 45 to remain generally 
uncompressed. Meanwhile, rod 52, is movably positioned with respect to 
pipe P, such that the tip 55 of end bit 53 rests in touching contact with 
pipe P. 
Locking element 39a is then projected into channel 39b as described above 
in conjunction with FIG. 1B, such that in accordance with a preferred 
embodiment of the invention, cutting edge 33 is maintained at a 
predetermined minimum distance, d, from the closest point of tangential 
contact with pipe P. For reasons which will be understood from the 
description below, this minimum distance d, is preferably equal to, or 
greater than, the thickness of the pipe wall. 
Following the positioning of rod 52 and arrangement of locking element 39a, 
compression nut 41 is further threadedly rotated along connector 24 (FIG. 
2), thereby compressing resilient element 45 between support portion 37 
and end bearing portion 46, so as to apply an axial force to support 
portion 37. Since rod 52 is connected to support portion 37 via valve 
conduit 31, end cap 39 and locking element 39a, the compression of 
resilient element 45 will have the consequential effect of transferring an 
axial force to end bit 53 at the point of contact with pipe P. As 
described hereinbelow, this axial force assists in the threaded insertion 
of end bit 53 into pipe P. 
Following compression of resilient element 45 (FIG. 2), rod 52 is rotated 
in a predetermined direction, x (FIG. 3), so as to correspond with the 
direction of thread 54 formed upon end bit 53. Rod 52 is rotated via an 
end 57 thereof, preferably with a suitable spanner or the like (not 
shown). Under the axial force exerted upon end bit 53 by compressed 
resilient element 45, and the rotational force which arises from the 
turning of rod 52, end bit 53 begins to threadably penetrate pipe P. At 
the same time, cutting edge 33--which is connected to rod 52 via conduit 
31, end cap 39 and locking element 39a--moves closer towards pipe P as a 
consequence of end bit 53 penetrating the pipe. 
In accordance with performing the method of the invention using a preferred 
embodiment of the invention as described above, rod 52 is rotated until 
such time as end bit 53, penetrates through the pipe wall of pipe P, and 
cutting edge 33 comes into touching contact with pipe P. Following this 
process, locking element 39a is withdrawn from channel 39b (FIG. 3A), so 
that conduit 31 becomes functionally disconnected from rod 52 of gripping 
device 50. 
It will be appreciated from the above description, that as valve conduit 31 
and cutting edge 33 draw closer towards pipe P upon end bit 53 threadably 
penetrating the pipe, resilient element 45 becomes gradually decompressed. 
Thus, in accordance with the method of the invention, compression nut 41 
is once again rotated along connector 24 (FIG. 4) in a manner similar to 
that described above, so as to compress resilient element 45 once more and 
thus apply a further axial force to support portion 37. As previously 
noted, this axial force is intended to aid in the cutting of coupon C from 
pipe P as is described hereinbelow. 
Following the above-mentioned further rotation of compression nut 41, valve 
30 is then rotated as depicted in FIG. 5, so that cutting edge 33 engages 
pipe P in a radial cutting motion, thereby creating a rotational 
frictional force between the cutting edge and a corresponding circular 
portion of the pipe. Such rotation of valve 30 may be achieved for 
example, by manually grasping and turning end cap 39 together with outlet 
portion 36 of conduit 31. Under the axial force applied to support portion 
37 and transferred to cutting edge 33 via conduit 31, this rotation of 
valve 30 causes cutting edge 33 to penetrate a portion of pipe P. 
In accordance with the method of the invention, valve 30 is continued to be 
rotated until such time as cutting edge 33 completely penetrates the pipe 
wall so as to form a disc-shaped coupon C as illustrated. In a preferred 
embodiment of the invention, the conclusion of this cutting process is 
indicated when sealing element 35a becomes tightly compressed between 
spacer ring 35b and inner shoulder 24a of connector 24. As is also 
illustrated in FIG. 5, coupon C is held in place by end bit 53 of rod 52 
after having been cut from pipe P. 
As will be appreciated by persons skilled in the art, the above-described 
cutting process will be enhanced, where a strong axial force, applied at 
the point of contact between cutting edge 33 and pipe P, is maintained. 
Thus, in accordance with an alternative method of the invention, 
compression nut 41 and valve 30 are alternately rotated so as to 
periodically compensate for the gradual decompression of resilient element 
45 which occurs as cutting edge 33 enters pipe P. 
Referring now also to FIG. 6, compression nut 41 is threadedly rotated 
along connector 24 in accordance with the method of the invention, until 
resilient element 45 becomes completely compressed. In a preferred 
embodiment of the invention, the completion of this compression process 
may be indicated when the compression nut's inward facing thread 42 
reaches an end 25a of thread 25 as depicted in FIG. 6. The resulting 
compression of resilient element 45, assists in reinforcing the axial 
sealing force applied to sealing element 35a via support portion 37, 
conduit 31 and spacer ring 35b. 
Thereafter, end nut 56 is threadedly rotated along the end located threaded 
portion 52a (FIG. 1A) of rod 52, until it comes into pressing contact with 
an adjacent end 39c of end cap 39 (FIG. 5). Subsequent rotation of end nut 
56 will then be operative to translate rod 52, end bit 53 and the 
threadedly attached coupon C, in an axial direction away from pipe P, 
thereby dislodging the coupon from the inner recess of cutting edge 33. 
Once coupon C has been sufficiently dislodged from cutting edge 33, it may 
easily be drawn through conduit 31 and a sufficiently sized opening 38d in 
valve element 38b, by means of translating rod 52 with the aid of end 57 
thereof (FIG. 6). A sealing element 72--which is preferably formed as an 
annular seal affixed between rod 52 and end cap 39 (FIGS. 1B, 3A, and 
6)--prevents the escape of gaseous or liquid material which enters conduit 
31 as the coupon is being withdrawn from pipe P to outlet portion 36. 
Once rod 52 and attached coupon C have been moved through conduit 31 and 
valve mechanism 38, the valve mechanism is set in a closed position (FIG. 
6) with the aid of handle 38a (FIG. 5), so that valve member 38b is 
pivoted so as to block the passage of any fluid (not seen) which flows 
from pipe P into conduit 31. 
Thereafter, end cap 39 with attached rod 52, end bit 53 and coupon C, are 
removed, and sealingly replaced with an ancillary device or branch pipe, 
referenced 90 (FIG. 7), whereupon valve mechanism 38 may then be reopened 
to allow for through-flow of fluid from pipe P to ancillary device or 
branch pipe 90, via conduit 31. 
Alternatively, end cap 39 with attached rod 52, end bit 53 and coupon C, 
may be removed and sealingly replaced with a removable sealing cap (not 
shown), until such time as an additional device or branch pipe is required 
to be installed. 
It will readily be appreciated from the above description and the 
illustrations provided in FIGS. 5 and 6, that once cylindrical cutting 
edge 33 has been operative to cut a portion of pipe P, the cutting edge 
and associated cutting element 34 or inlet portion 32 (as the case may 
be), will remain within the opening, O, formed in the pipe wall of pipe P 
(FIG. 6), even after coupon C is removed from the pipe wall area. Thus it 
will be appreciated by persons skilled in the art, that the mating 
engagement between cutting edge 33 and a portion of pipe P, provides a 
significant degree of stabilization around the area of engagement, thereby 
preventing the newly joined valve from being accidentally moved out of 
alignment with the opening formed in pipe P. 
It will also readily be appreciated by persons skilled in the art, that 
alternative embodiments of the invention are envisaged, and which, 
although not described in detail herein, are intended to be covered by the 
above description. By way of non-limiting example only, FIG. 8 illustrates 
a first alternative embodiment of the invention, referenced generally 10', 
wherein mounting 20' is simply formed as a connector 24' (i.e. without 
additional mounting portions) and is arranged for connection to a pipe P, 
by means of welding. 
Similarly, FIG. 9 illustrates a pipe tapping device, referenced generally 
10", constructed and arranged in accordance with a second alternative 
embodiment of the invention, and attached to a pipe P. The construction 
and operation of device 10" is generally similar to that of device 10 
described hereinabove, however an alternative valve mechanism 38" is 
provided so as to help reduce the production costs incurred in making the 
device. In contrast to the pivotable ball valve mechanism 38 incorporated 
in device 10 described above (FIGS. 1-7), valve mechanism 38" employs a 
valve element 38b" which is linearly translated from a first position, 
referenced A, to a second position, referenced B, so as to open valve 30" 
to through-flow of a fluid (not shown). 
In accordance with the method of the invention used to operate device 10", 
a cut coupon C is withdrawn to an extreme end 31a of conduit 31", along 
with valve element 38b", so as to allow for through-flow of a liquid from 
the tapped pipe P to a branch pipe referenced 90", via outlet portion 36" 
of valve 30". As seen in FIG. 9, outlet portion 36" is transversely 
arranged with respect to the remainder of valve conduit 31". 
Further, although the gripped coupon C remains housed within end 31a of 
valve 30", the majority portion of rod 52" which has been withdrawn from 
the remainder of device 10", may be detached from the portion of rod 
remaining within the device at a rod joint (not seen) provided for this 
purpose. 
Thus, it will be appreciated by persons skilled in the art that the scope 
of the present invention is not limited by what has been illustrated and 
described hereinabove, merely by way of example. Rather, the scope of the 
present invention is limited solely by the claims which follow.