U.S. patent application number 14/122990 was filed with the patent office on 2014-12-04 for method and device for monitoring integrity of wooden posts.
The applicant listed for this patent is United Technologists Europe Limited. Invention is credited to Frank Gerwin Kaufhold.
Application Number | 20140352458 14/122990 |
Document ID | / |
Family ID | 45939793 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140352458 |
Kind Code |
A1 |
Kaufhold; Frank Gerwin |
December 4, 2014 |
METHOD AND DEVICE FOR MONITORING INTEGRITY OF WOODEN POSTS
Abstract
Method and Device for Monitoring Integrity of Wooden Posts A
device (10) for monitoring the integrity of a wooden post (40)
comprises an outer sleeve (11), a moveable pin (12), driving means
(24) and indicating means (50). The outer sleeve (11) is adapted to
be mounted in a pre-formed recess (41) of complementary size and
shape extending from the outer surface (43) of a wooden post (40)
substantially into the centre (45) thereof. The moveable pin (12)
is mounted within the outer sleeve (11) and has a head (18)
arranged normally to bear against wood at the centre (45) of the
post (40). The driving means (24) is arranged to urge the pin head
(18) against wood at the centre (45) of the post (40). The
indicating means (50) denotes any movement of the pin (12) further
into the post (40). When in use in a method of monitoring the
integrity of a wooden post (40), the device (10) is located in a
pre-formed recess (41) and the indicating means (50) is used
periodically to monitor any movement of the pin (12) further into
the post (40).
Inventors: |
Kaufhold; Frank Gerwin;
(Suffolk, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Technologists Europe Limited |
Suffolk |
|
GB |
|
|
Family ID: |
45939793 |
Appl. No.: |
14/122990 |
Filed: |
January 15, 2013 |
PCT Filed: |
January 15, 2013 |
PCT NO: |
PCT/GB2013/050076 |
371 Date: |
November 27, 2013 |
Current U.S.
Class: |
73/865.8 |
Current CPC
Class: |
G01N 19/00 20130101;
G01M 5/0058 20130101; G01N 33/46 20130101; G01N 3/40 20130101 |
Class at
Publication: |
73/865.8 |
International
Class: |
G01N 33/46 20060101
G01N033/46; G01N 19/00 20060101 G01N019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2012 |
GB |
12 02760.3 |
Claims
1. A device for monitoring the integrity of a wooden post,
comprising: an outer sleeve adapted to be mounted in a pre-formed
recess of complementary size and shape extending from the outer
surface of a wooden post substantially into the centre thereof; a
moveable pin mounted within the outer sleeve and having a head
arranged normally to bear against wood at the centre of said post;
driving means comprising a spring for urging the pin head against
wood at the centre of said post; and indicating means for denoting
any movement of the pin further into said post.
2. (canceled)
3. A device as claimed in claim 1, wherein the sleeve and pin are
each generally cylindrical.
4. A device as claimed in claim 1, wherein the outer sleeve and the
pin are of substantially equal length.
5. A device as claimed in claim 1, wherein the sleeve is adapted to
be permanently installed in said wooden post.
6. A device as claimed in claim 1, wherein the outer sleeve has a
first aperture at a first end thereof, adapted to be located at or
adjacent the outer surface of said wooden post, and a second
aperture at a second end thereof, adapted to be located at or
adjacent the centre of said wooden post.
7. A device as claimed in claim 6, wherein the pin has a first end
arranged normally to be located within the first aperture of the
sleeve, and a second end having the pin head, arranged normally to
be located with the second aperture of the sleeve.
8. A device as claimed in claim 7, wherein the location of the
first end of the pin within the first aperture of the sleeve is
normally visible, such that said first aperture and said first end
of the pin constitute said indicating means for denoting any
movement of the pin further into said post.
9. A device as claimed in claim 8, wherein said indicating means
for denoting movement of the pin into the post further comprise a
measuring rod adapted for insertion into the first aperture of the
sleeve, so as to determine the extent of movement of the pin into
said post.
10. A device as claimed in claim 9, wherein the measuring rod is
provided with markings so as visually to indicate the extent of
movement of the pin into said post.
11. A device as claimed in claim 9, wherein the measuring rod is
calibrated to indicate a pre-determined acceptable limit of
movement of the pin.
12. A device as claimed in claim 1, wherein the sleeve comprises an
external screw thread extending partially down the length thereof
adjacent a first end thereof, to enable the sleeve to be securely
mounted within said recess.
13. A device as claimed in claim 1, wherein the outer sleeve
comprises a hexagonal bolt head fitting at a first end thereof, to
facilitate mounting within said recess.
14. (canceled)
15. A device as claimed in claim 1, wherein the spring is a high
tensile spring
16. A device as claimed in claim 1, further comprising a first
shoulder provided on the sleeve, part-way along the internal
surface thereof, and a second shoulder formed at the junction of
the pin with the pin head, and wherein the spring is normally
arranged to be compressed between said first and second
shoulders.
17. A device as claimed in claim 1, wherein the pin is provided
with one or more O-rings to provide a seal against the ingress of
moisture.
18. A device as claimed in claim 17, wherein the pin head is
provided with an O-ring adjacent its junction with the pin.
19. A device as claimed in claim 17, wherein the pin is provided
with an O-ring adjacent its first end.
20. A device as claimed in claim 1, wherein the pin head has a
conical profile at the end thereof adapted to bear against wood at
the centre of said post.
21. A device as claimed in claim 1, further comprising a safety
clip to retain the pin within the sleeve during installation.
22. A method of monitoring the integrity of a wooden post
comprising the steps of: forming a recess, extending from the outer
surface of said wooden post substantially to the centre thereof;
locating in said recess a device, the device comprising: an outer
sleeve adapted to be mounted in the recess, the recess being of
complementary size and shape; a movable pin mounted within the
outer sleeve and having a head arranged normally to bear against
wood at the centre of said post; driving means comprising a spring
for urging the pin head against wood at the centre of said post;
and indicating means for denoting any movement of the pin further
into said post; and periodically monitoring any movement of the
device pin further into the post.
23. (canceled)
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. (canceled)
30. (canceled)
31. (canceled)
32. (canceled)
33. (canceled)
Description
[0001] This invention relates to a method and device for monitoring
the integrity of a wooden post, such as a telegraph pole. In
particular, the invention relates to such a method and device for
ascertaining whether the structural integrity of telegraph poles
may have been compromised by rot. The terms "pole" and "post" are
used interchangeably herein.
[0002] Wooden telegraph poles (sometimes referred to as utility
poles) are used to carry overhead telephone cables and power lines.
Periodic access to the overhead cables is required for routine
maintenance and repair, and this is generally achieved by a
technician climbing the pole. In order for this to be done safely,
the technician must first ascertain that the pole has sufficient
integrity to support his weight.
[0003] Being constructed of wood and partially buried in the
ground, all telegraph poles will eventually succumb to rot, which
compromises the structural integrity of the pole and makes it
unsafe for a technician to climb. Telegraph poles are generally
pressure-treated with wood preservative such as creosote to prevent
rot and so extend the lifetime of the pole--but despite the
pressure treatment, the preservative will never fully penetrate
into the centre of the pole. As a consequence, the pole will
eventually rot in the centre, with the outer layers of wood often
remaining more or less intact, effectively forming a hollow tubular
structure. A pole in this state may still perform adequately in its
primary function of supporting overhead cables, and may exhibit no
external signs of degradation. However, a hollow pole is likely to
be incapable of safely supporting the weight of a technician.
[0004] The useful lifetime of a wooden telegraph pole will vary
according to the climatic conditions of the area in which the pole
is installed--for example a pole in a particularly wet or humid
area will rot faster, and so need replacing sooner, than a pole in
an area with a dry climate. In temperate climates such as that of
the United Kingdom, the typical lifetime of telegraph pole is
around 20 years. Network operators generally seek to replace the
oldest poles in their network on a rolling basis, but this can be a
difficult operation to monitor due to the sheer number of poles in
a network. Moreover, it is essentially impossible to predict
exactly when any particular pole will have reached the acceptable
limits of structural integrity from the point of view of technician
safety.
[0005] Existing proposals for the solution of the above identified
problems are considered to be unsatisfactory on the basis of
safety, reliability, efficiency and cost. One existing method for
verifying the structural integrity of a pole prior involves the
measurement of the acoustic properties of a pole, and comparison of
the results with known measurements of structurally sound poles.
Problems with this method include the cost of the acoustic
measurement equipment, the level of skill required for the
equipment to be operated--which may necessitate an additional
technician, and issues surrounding the reliability of the results,
since these are based on an indirect measurement--i.e. measurement
of a property of the wood (acoustics) affected by rot, but not
direct measurement of the extent of the rot itself.
[0006] A crude, but widely used, variant of this method involves
the technician simply tapping the pole with a hammer, and making an
assessment of the pole's structural integrity simply on the basis
of the sound made. Clearly, this method is highly subjective since
it relies on the experience and judgment of the individual
technician, and cannot be considered safe even for the most
experienced technician.
[0007] The present invention seeks to address the above-identified
problems by proposing a reliable and economic device and method for
safely and efficiently monitoring the integrity of wooden posts,
such as telegraph poles, which device and method provide an instant
indication based on a direct measurement of the extent of rot
within the centre of the pole.
[0008] According to a first aspect of the present invention there
is provided a device for monitoring the integrity of a wooden post,
comprising:
[0009] an outer sleeve adapted to be mounted in a pre-formed recess
of complementary size and shape extending from the outer surface of
a wooden post substantially into the centre thereof;
[0010] a moveable pin mounted within the outer sleeve and having a
head arranged normally to bear against wood at the centre of said
post;
[0011] driving means for urging the pin head against wood at the
centre of said post; and
[0012] indicating means for denoting any movement of the pin
further into said post.
[0013] The present invention has been developed for use in
monitoring the structural
[0014] integrity of telegraph poles, and in particular for
monitoring the extent to which the pole may have rotted at its
centre, and the invention is therefore described herein with
particular reference to this use. However, it should be understood
that the scope of the present invention encompasses its use for
monitoring the integrity of substantially all types of wooden
posts.
[0015] The terms "normal" and "normally" as used herein with
reference to the position of the pin and pin head, refer to the
condition of the device of the present invention when installed in
a new wooden post, before any rotting of the post has occurred.
[0016] The device according to the present invention operates on
the principle that the hard wood present at the centre of a new
post will resist the movement of the pin head further into the
post, despite the driving means urging the pin head against the
wood. As the wood at the centre of the post rots and becomes soft,
the driving means will urge the pin further into the post, which
movement will be denoted by the indicating means, thus enabling a
technician to ascertain the integrity of the post by periodically
monitoring the indicating means.
[0017] The sleeve and pin are preferably each generally
cylindrical, and of substantially equal length. The pin head
preferably has a conical profile at the end thereof adapted to bear
against wood at the centre of said post. The sleeve is preferably
adapted to be permanently installed in the wooden post.
[0018] In order to facilitate the operation of the device, the
sleeve preferably has a first aperture at a first end thereof,
adapted to be located at or adjacent the outer surface of the
wooden post, and a second aperture at a second end therefore,
adapted to be located at or adjacent the centre of said wooden
post. The pin preferably has a first end arranged normally to be
located within the first aperture of the sleeve, and a second end
having the pin head, arranged normally to be located within the
second aperture of the sleeve.
[0019] The location of the first end of the pin within the first
aperture of the sleeve is normally visible from the outer surface
of the wooden post, such that the first aperture of the sleeve and
the first end of the pin together constitute said indicating means
for denoting any movement of the pin further into said post. That
is to say if, on periodic monitoring of the indicating means, the
first end of the pin is visible in, and substantially flush with,
the first aperture of the sleeve, then it is apparent that the pin
head has not moved further into the post from its normal position,
and thus that no rotting of the post has occurred. However if, on
periodic monitoring of the indicating means, the first end of the
pin is not visible in the first aperture of the sleeve, or is
displaced inwardly relative to said first aperture, then it is
apparent that the pin has moved further into the post, consequent
upon the presence of rot in the centre of the post. The degree of
rot in the centre of the post will be denoted by the degree to
which the first end of the pin is displaced inwardly relative to
the first aperture of the sleeve.
[0020] In a preferred embodiment of the present invention, the
indicating means preferably further comprises a measuring rod
adapted for insertion into the first aperture of the sleeve, so as
to determine the extent of movement of the pin into said post. The
measuring rod constitutes a separate component, not permanently
installed in the post, which will be utilised by the technician for
periodic monitoring of the position of the pin. The measuring rod
may be provided with markings so as visually to indicate the extent
of movement of the pin into said post, when the measuring rod is
inserted into the first aperture of the sleeve. The measuring rod
is preferably calibrated to indicate a pre-determined acceptable
limit of movement of the pin, corresponding to a pre-determined
acceptable limit of the extent of rot within the post beyond which
the structural integrity of the post is considered unsafe for a
technician to climb.
[0021] In order to facilitate the secure mounting of the sleeve in
the recess, the sleeve preferably comprises an external screw
thread extending partially down the length thereof adjacent the
first end. The sleeve preferably further comprises a hexagonal bolt
head fitting at the first end thereof, around the first
aperture.
[0022] The driving means for urging the pin head against the wood
at the centre of the post preferably comprises a spring, and most
preferably a high tensile spring. The tensile strength of the
spring can be selected in order to calibrate the device, depending
on the type of wood and size of pole.
[0023] The driving means preferably further comprise a first
shoulder provided on the sleeve, part-way along the internal
surface thereof, and a second shoulder formed on the pin head at is
the junction with the pin, wherein the spring is normally arranged
to be compressed between said first and second shoulders. The
spring is normally held in a state of compression by the hard wood
at the centre of the post resisting the further motion of the pin
head. As the wood rots, the compression in the spring is released,
thus urging the pin head further into the wood. The device
preferably comprises a removable safety clip to retain the pin in
its normal position within the sleeve during installation.
[0024] In order to provide a seal against the ingress of moisture,
the pin is preferably provided with one or more O-rings. Most
preferably, the pin is provided with one O-ring adjacent its
junction with the pin head, and one O-ring adjacent its first end.
The device may desirably also be sealed with silicone sealant
around the boundary between the sleeve and the wooden post. A
removable protective cap may also be provided to cover the first
aperture of the sleeve. The device is preferably formed of metal,
most preferably steel.
[0025] The scope of the present invention extends to include a
method of monitoring the integrity of a wooden post, such as a
telegraph pole, utilising a device according to the first aspect of
the present invention as hereinbefore described.
[0026] Therefore, according to a second aspect of the present
invention, there is provided a method of monitoring the integrity
of a wooden post comprising the steps of:
[0027] forming a recess, extending from the outer surface of said
wooden post substantially to the centre thereof;
[0028] locating in said recess a device according to the first
aspect of the present invention as hereinbefore described; and
[0029] periodically monitoring any movement of the device pin
further into the post.
[0030] The recess is preferably formed by drilling, so as to be of
complementary size and shape to the device. Most preferably, the
recess and device are each generally cylindrical.
[0031] The recess is preferably formed at an angle in the range of
from 30.degree. to 60.degree., most preferably 45.degree. relative
to the horizontal, and arranged such that the centre thereof is at
or below ground level, but with the end of said recess located on
the surface of the wooden post remaining above ground level when
the post is installed.
[0032] The method according to the second aspect of the present
invention preferably comprises an additional step of periodically
monitoring movement of the device pin further into the post
utilising a measuring rod as hereinbefore described. The method may
also further comprise an additional preliminary step of calibrating
the measuring rod to indicate a pre-determined acceptable limit of
movement of said device pin, corresponding to a pre-determined
acceptable limit of the extent of rot within the post beyond which
the structural integrity of the post is considered unsafe for a
technician to climb.
[0033] The step of locating the device in the recess in the wooden
post preferably involves permanently installing the sleeve, most
preferably by means of the external screw-thread thereon as
hereinbefore described. The step of locating the device in the
recess preferably also involves sub-steps of: lubricating the
sleeve and/or the recess to facilitate the insertion of the sleeve
into the recess; and/or sealing the sleeve in the recess so as to
prevent ingress of moisture. Silicone sealant may be utilised for
the sealing step, and may also be utilised for the lubrication
step.
[0034] During location of the device in the recess, the device pin
is preferably held in its normal position by means of a safety
clip. The step of locating the device in the recess is then
preferably followed by a sub-step of removing said safety clip to
prime the device.
[0035] In order that the present invention may be clearly
understood, a preferred embodiment thereof will now be described in
detail, though only by way of example, with reference to the
accompanying drawings, in which:
[0036] FIG. 1 shows a perspective view of a device for monitoring
the integrity of a wooden post, according to the first aspect of
the present invention;
[0037] FIG. 2 shows a partially cross-sectional view of the device
of FIG. 1;
[0038] FIG. 3 shows a cross-sectional view of the device of FIGS. 1
and 2 installed in a new wooden post so as to be utilised in a
method according to the second aspect of the present invention;
and
[0039] FIG. 4 shows a cross-sectional view of the device and post
of FIG. 3 during monitoring when the wooden post is new; and
[0040] FIG. 5 shows a cross-sectional view the device and post of
FIGS. 3 and 4 during monitoring when the wooden post has rotted
internally.
[0041] Referring first to FIGS. 1 and 2, there is shown a preferred
embodiment of a device, generally indicated 10, according to a
first aspect of the present invention, for monitoring the integrity
of a wooden post. The device 10 comprises an outer sleeve 11 having
a moveable pin 12 mounted therein, as can best be seen from FIG. 2.
The sleeve 11 is shown in FIG. 2 in a cross-sectional view in order
to show the pin 12 therewithin. As can be seen, the pin 12 is
substantially wholly enclosed within the sleeve 11, and hence only
a first end 13 of the pin 12 can be seen in FIG. 1, said first end
13 protruding through a first aperture 14 at the first end 15 of
the sleeve 11. As can also best be seen from FIG. 2, the second end
16 of the sleeve 11 has a second, larger aperture 17, within which
is located a pin head 18 carried on the second end 19 of the pin
12. The pin head 18 terminates in a generally conical end 21.
[0042] As can best be seen from FIG. 1, the sleeve 11 is provided
with an external screw thread 22 adjacent its first end 15, to
enable the device 10 to be securely mounted within a recess in a
wooden post. The first end 15 of the sleeve 11 is also provided
with a hexagonal bolt head fitting 23, around the first aperture
14, to enable the use of conventional tools for mounting the device
10 in a post.
[0043] Referring again to FIG. 2, it can be seen that the pin 12
passes through the centre of a spring 24. The spring 24 is arranged
to bear at one end 25 thereof against a first-shoulder 26 formed
part-way down the internal surface 27 of the sleeve 11, and at its
other end 28 against a second shoulder 29 formed at the junction 31
of the pin 12 and the pin head 18. As will be described in more
detail below with reference to FIGS. 3 to 5, when the device 10 is
installed in a new wooden post, the pin 12 is required to be in its
"normal" position--i.e. fully retracted into the sleeve 11, with
the first end 13 of the pin 12 located in the first aperture 14 of
the sleeve 11. This requires the spring 24 to be fully compressed
between the first and second shoulders 26, 29, and held in that
compressed state, else the pin 12 would be fired out of the second
end 16 of the sleeve 11, with some force. In order to achieve this,
the first end 13 of the pin 12 is provided with a safety clip 32,
as can best be seen in FIG. 1. The safety clip 32 retains the pin
12 in position during installation of the device 10, and is then
removed to prime the device 10 ready for use.
[0044] In order to provide a seal against the ingress of moisture,
the pin 12 is provided one rubber O-ring in a first groove 33
adjacent the junction 31 of the pin 12 with the pin head 18, and
one rubber O-ring in a second groove 34 adjacent the first end 13
of the pin 12. Note that for clarity, the rubber O-rings themselves
are omitted from FIG. 2, though the grooves 33, 34 for receiving
them are clearly visible.
[0045] A preferred embodiment of a method, according to the second
aspect of the present invention, of monitoring the integrity of a
wooden post, utilising a device 10 according to the first aspect of
the present invention, will now be described with reference to
FIGS. 3 to 5.
[0046] Referring first to FIG. 3, a new wooden post 40 to be used
as a telegraph pole has a cylindrical recess 41 drilled therein.
The cylindrical recess 41 is sized so as to be complementary to the
device 10 according to the first aspect of the present invention,
to ensure a secure fit, and so as to extend from an upper 42 end at
the outer surface 43 of the wooden post 40 to a lower end 44
substantially at the centre 45 of the post 40. The recess 41 is
angled at approximately 45.degree. relative to the horizontal, such
that the top end 42 remains above ground level 46 whilst the lower
end 43 is located below ground level 46, when the post 40 is
installed.
[0047] The device 10 is then inserted into the recess 41 using a
conventional power drill and driver, or similar, engaged with the
hexagonal bolt head fitting 23. A silicone-based lubricant is used
to ease the insertion of the device 10 into the recess 41, and
subsequently to act as a sealant against the ingress of moisture.
As the device 10 is driven into the recess 41, the external screw
thread 22 engages with the wooden post 40 to ensure a secure fit.
The device 10 is correctly located in the recess 41 when the end 21
of the pin head 18 bears against the hard wood at the centre 45 of
the post 40 (i.e. at the lower end 44 of the recess 41). The first
end 15 of the device 10, carrying the aperture 14 will now be
either flush with the surface 43 of the post 40, or if desired may
be slightly counter-sunk below the surface 43, as shown in FIG.
3.
[0048] During installation, it is necessary for the pin 12 to be
held in its "normal" position, with the spring 24 held in a state
of compression between the first and second shoulders 26, 29, using
the safety clip 32, as described above with reference to FIGS. 1
and 2. Once the device 10 is installed in the post 40 as shown in
FIG. 2, the safety clip 32 can then be removed in order to prime
the device 10 ready for use. The motion of the pin head 18 is then
resisted by the hard wood at the centre 45 of the post 40, against
the force of the spring 24, which would otherwise drive the pin 12
further into the post 40.
[0049] Referring now to FIG. 4, this shows the device 10 shortly
after installation in the post 40, and before any rotting of the
post 40 has taken place. The pin head 18 thus still bears against
the hard wood at the centre 45 of the post 40 (that is, at the
lower end 44 of the recess 41), and no movement of the pin 12 has
taken place. Although not visible from FIG. 4, the first end 13 of
the pin 12 will thus still be substantially flush with the aperture
14 at the first end 15 of the device 10. Depending on the degree to
which the first end 15 of the device is counter-sunk into the upper
end 42 of the recess 41, it may be possible for a technician to
verify this from a visual inspection of the upper end 42 of the
recess 41. However, for a more reliable indication, and to obtain
an accurate measurement of any movement of the pin 12 into the post
40, the technician uses a measuring rod 50 for periodic monitoring
of the post 40.
[0050] The measuring rod 50 is in the nature of a dip-stick, and is
inserted into the aperture 14 at the first end of the device 10,
until contact is made between the measuring rod 50 and the first
end 13 of the pin 12. The measuring rod 50 carries graduated
markings 51, to be read at the point where the rod 50 enters the
aperture 14, to indicate the extent of any movement of the pin
12.
[0051] The measuring rod 50 is also calibrated to indicate a
pre-determined acceptable limit 52 of movement of the pin 12,
corresponding to a pre-determined acceptable limit of the extent of
rot within the post 40 beyond which the structural integrity of the
post 40 is considered unsafe for a technician to climb. As can be
seen from FIG. 4, for ease of reference for the technician, the
measuring rod 50 is divided into colour-coded zones either side of
the limit 52, with a green coloured "safe" zone 53 formed on the
lower part of the rod 50, and a red coloured "danger" zone 54
formed on the upper part of the rod 50. As with the graduated
markings 51, the reading of the "safe" and "danger" zones 53, 54 is
to be carried out at the point where the rod 50 enters the aperture
14. As can be seen from FIG. 4, since there has been no movement of
the pin 12, the measuring rod 50 returns a reading in the "safe"
zone 53, and so the post 40 is safe to climb.
[0052] Referring now to FIG. 5, this shows the same post 40, with
the device 10 still permanently installed therein, some years later
when significant rotting of the post 40 has occurred. Rotting of
treated wooden posts 40 occurs from the bottom upwards and from the
centre 45 outwards, in a rising, generally conical pattern 60, as
shown in FIG. 5. The wood in the rotten area 60 of the post 40 will
be significantly softer than in the remainder of the post 40. As
such, once the rot 60 reaches the lower end 44 of the recess 41,
the wood at the centre 45 of the post 40 is no longer capable of
resisting the movement of the pin head 18 and the expansion of the
spring 24. The spring 24 thus expands, driving the pin head 18 out
through the lower end 44 of the recess 41, and through the rotten
area 60 until it again reaches hard wood in the remainder of the
post 40.
[0053] Periodic monitoring of the post 40 by inserting the
measuring rod 50 into the aperture 14, now requires the rod 50 to
be inserted considerable further into the device 10 before contact
is made between the rod 50 and the first end 13 of the pin 12.
Consequently, the measuring rod 50 now returns a reading in the
"danger" zone 54, indicating that the post 40 is unsafe for the
technician to climb, and is in need of replacement.
* * * * *