Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE AND \,LETTrIUD FOR TRIPPNG A C ABLE
This is a divisional of Canadian Patent application No. 2,341,537.
TECHNIC.-kL. FIELD
The present invention relates to cable strippers for use with cable anchors
for use in post-
tension concrete structures. More parlicularh,. the present invention relates
to devices for strippinj
cable sheath from end portions of cables which are to be secured bv the cable
anchors. The present
invention also relates to a method of stripping a sheath from an end portion
of a cable.
BACItiGRC>LTIN~D ART
The prior art is replete vvith concrete construction cable tensioning svstems.
These systems
includz both pre-stressed and post-tensioned cables and wire rope. EngineerinQ
in the post-tensioninQ
of concrete is a well developed technology and the utilizat.ion of such
tendons eltendina througlt a
concrete slab or beam is conventional. The tendons provide structural strenoth
for the concrete in
a manner and at a cost not lieretofore possible with conventional rebar
con.struction. Utilization of
such tendons does, hocvever, require anchor assemblies on opposite ends
thereof and the termination
of the cable itself at the anchors. The anchor assemblv secures the ends of
the terminated tendons
estendinQ throu--h the concrete bed wherebij the tendons remain taut and
effectrEe during the life-span
of the construction. The effect.iveness requires the protection of the
terminated tendons, which are
usuallv made of steel or the lihe, from corrosion. Corrosion forces are well
known to cause
deterioration in the strenath of the concrete if allowed to jeopardize the
inteQrin, of tensioning
members. To prevent corrosion of the tendon. the steel fibers are usuall-v
sheathed in a plastic
membrane throuQhout the lenLy-tlt of the slab. The membranes do, however.
require terrnination at
the point where the tendons are secured within the anchor assemblies. The
reason is obviouslv to
provide appropriate structural intearity at the secured portion.
In the process of post-tensionin,a, it is important that the tendon is free to
move within the
hardened concrete so that the tensile load on the tendon is evenly distributed
along the entire length
of the structure. Methods used to ensure that the tendons provide free
movement within the hardened
concrete include laNq'ng a number of strand.s of wire in a sheath. it is
within this sheath that the strands
of wire are stressed after the concrete is hardened. After stressinQ_ the
wires exposed from the ends
of the anchor assembIies are then cut-off or terminated.
Durina such post-tensiornua of a concrete strueture. it is lcnown to insert an
end of a cable,
usuallv referred to as a "tendon", into a tapered passage ex-tendinQ through a
cable anchor, and then
to secure the cable to the cable anchor by means of wedQes inserted into the
tapered passage into
engagement with the cable. However, before the insertion of the wedaes, it is
necessarv to strip the
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sheath from the end portion of the cable. So as to preserve the "encapsulated"
condition of such
anchor assemblies and such cable, it is desirable to terminate the sheathing
of the cable at a point just
rearward of the end of the wedges within the tapered bore of the anchor. As
such, a more effective
enclosing of the steel strands of wire within the cable is achieved.
U. S. Patent No. 5,632,088, issued on May 27, 1997, to Naso et al., for a
cable stripper
device. The purpose of this cable stripper device is to aIIow for the
stripping of the sheathing from
the cable at a location just rearward of the end of the wedges within the
tapered passage of the
anchor. This cable stripper device has an elongate cutter on a tubular body.
The cable stripper has
a cutter at one end thereof with an inwardly projecting transverse cutt.er
blade. The cutter and the
tubular bodv are connected so as to allow the cutter to move relative to the
tubular body. The tubular
bodv is insertable into the tapered passage of the cable anchor. The tubuiar
bodv has a frusto-conical
surface so as to wedge the cutter blade into penetrating engagement with a
sheath on the cable. The
cutter blade is hingedly connected to the tubular body so as to be capable of
moving inwardly and
outwardlv relative to the relative position of the end of the tubular body
within the tapered passage
of the anchor. The cutter blade is positioned at an end of this angular ann.
U. S. Patent No. 5,745,996, issued on May 5, 1998, to Kenny et aL, teaches a
device for
cutting sheathing from a tendon extending through an anchor assembly. This
device includes a
housing adapted to be rotatable about the sheathed tendon and a blade having a
cutting edge. The
blade cutting edge is oriented in a selected cutting position within the
anchor assembly when the
housina is mounted on the sheathed tendon and rotated thereabout. In
particular, this device includes
a means for securing the blade to the housing or placing the blade in a
position in contact with the
anchor assemblv inner wall so as to deflect the cutting edge toward the
sheathed tendon into contact
with the sheathing when the device is mounted on th e sheathed tendon.
Unfortunatelv, with these devices, in order to achieve the proper "cutti.ng"
effect, it is
necessary to first insert the tool into the tapered passaae of the anchor.
When the tool has been
inserted as far as possible into the tapered passage, it is necessary to
hammer the opposite end of the
tubular body so as to cause the cutter blade to "plow" through the plastic of
the sheathing of the cable.
When the exterior of the tapered portion of the tubular body is in surface-to-
surface contact with the
inner wall of the tapered passage of the anchor, the tool can then be rotated
so that the cutter blade
creates a cut through the sheathing which is transverse to the longitudinal
axis of the cable.
Unfortunately, because of the strong forces that are required, the cutter
blade must be formed
of a hardened steel material. The arm having the cutter blade attached thereto
must be machined and
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strongly affixed to the tubular body. The effort required to hammer the
tubular body and to "piow"
through the plastic can be extreme at times. As a result. workers will tend to
take a more expedient
approach and simply rotate the tool at an improper location before the desired
position within the
tapered passaQe of the anchor. As a result, the sheathing may remain in those
areas which are to be
exposed to the wedges. The effect of "plowing" through the plastic material of
the sheathing in a
longitudinal direction alona the cable quickiy cau.ses the sharpness of the
cutter blade to deteriorate.
Furthermore, the tubular body of the tool requires that the entire tool be
threaded over the exterior
of the cable. Since the cable, in intermediate anchorages, can extend for a
relativelv long distance,
a great deal oflabor is required to properh- "thread" the cable througlt the
interior of the tubular body.
It is an object of the present invention to provide a method and apparatus for
the stripping of
sheathing from a cable which grips the cable in an easier and more effective
manner.
It is another object of the present invention to provide a method and device
which allows the
tool to be attached at any location adjacent to an intermediate anchor of a
post-tension system.
It is another object of the present invention to provide such a device which
does not require
"threadinQ" over the length of the cable.
It is a further object of the present invention to provide such a device which
facilitates the
insertion of the tool into the wedge cavity of the anchor.
It is still another object of the present invention to pro,~ide a cable
stripper device which avoids
the "plowing" through the material of the sheathing of the cable.
It is still another object of the present invention to provide a tool which
minimizes the
machining required for the formation of the cutter blade.
It is still a further object of the present invention to provide a cable
stripper device which
allows for a simultaneous "g:tippinQ" of the sheathing during the cutting
operation so as to facilitate
the removal of the sheathing from the cable.
It is still a further object of the present invention to provide a tool which
utilizes a stamped
cutter blade which can be quicldi, and easily replaced without the assi.stance
of additional tooLs.
It is still a further object of the present invention to provide a cable
stripper which is easy to
use, relatively inexpensive and easy to manufacture.
These and other objects and advantages of the present invenlion will become
apparent from
a reading of the attached specification and appended claims.
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SUMMARY OF THE IN"v'ENTTON
The present invention is a device for stripping a cable comprising a bodv
having a channel
extending therethrouglt so as to open at a narrow end of the body and a knife
affixed to the body so
as to have a blade with a cuttinna edge eltending upwardly into the channel.
The blade extends at an
angle of between 70 and 89 degrees cvith respect to the longitudinal axis of
the channel.
The bodv includes a handle and a cutting head affixed to an end of the handle.
The channel
e-tends through the handle and the cutting head. The knife is affi,Yed to the
cutting head. The handle
is compressible so as to reduce a diameter of the channel. The handle has
projections extending into
the channel. These projections are in the form of ribs extending parallel to
the longitudinal axis of
the channel. The cutting head is removabty affi,4ed to the handle. The handle
is fonned of a flexible
polymeric mateiial.
The cutting head has a notch e-xtending along an outer surface of the cutting
head. The knife
is received within this notch. The cutting head has a cutout area at the
narrow end. The blade
extends upwardly into the channel and through the cutout area. A locking
member is rotatably
mounted onto the cutting head. The locking member is movable between a first
position locking the
knife within the notch and a second position suitable for releasing the knife
from the notch. The knife
has a hole formed adjacent an end opposite the blade. The notch has a pin
formed therein. The hole
of the knife is received by the pin. The locking member abuts a surface of the
knife when in the first
position. The knife is formed of a stamped metal material. The blade has a
bottom surface. The
cuttinQ edge is inclined approlimately 15 deaz-ees with respect to this bottom
surface.
The present invention is also a method of stripping a sheathing from a cable
in an anchor of
a post-tension system including the steps of: (1) forming a tool having a
channel extending
therethrough with a knife affixed at one end of the channel; (2) inserting the
tool into the tapered bore
of the anchor until the knife engages the sheathing of the cable; (3) rotating
the tool around the cable
such that the knife draws the tool further into the tapered bore; (4)
squeezing the tool so as to
compressivelv contact the sheathing ea-terior of the tapered bore; and (5)
pulling the tool from the
tapered bore so as to remove a cut section of the sheathing from the tapered
bore. The tool is formed
so as to have a handle of a flexible polymeric material. This handle has
projections ea-tending into
the channel.
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According to one aspect of the invention, there is
provided a device for stripping a cable comprising: a body
having a channel extending therethrough, said body having a
narrow end, said channel opening at said narrow end, said
channel having a longitudinal axis, said body comprising a
handle having said channel extending longitudinally
therethrough, said channel defining a cable-receiving area
in a cross-section transverse to said longitudinal axis,
said handle being compressible so as to reduce a size of
said cable-receiving area; a knife affixed to said body so
as to have a blade with a cutting edge extending upwardly
into said channel, said blade extending at an angle of
between 70 and 89 degrees with respect to said longitudinal
axis; a cutting head affixed to an end of said handle, said
channel extending through said handle and said cutting head,
said knife affixed to said cutting head, said cutting head
having a notch extending along an outer surface of said
cutting head, said knife being received within said notch,
said cutting head having a cutout area at said narrow end,
said blade extending upward into said channel through said
cutout area.
According to another aspect of the invention,
there is provided a device for stripping a cable comprising:
a body having a channel extending therethrough, said body
having a narrow end, said channel opening at said narrow
end, said channel having a longitudinal axis; and a knife
affixed to said body so as to have a blade with a cutting
edge extending upwardly into said channel, said blade
extending at an angle of between 70 and 89 degrees with
respect to said longitudinal axis, said body comprising: a
handle; cutting head affixed to an end of said handle, said
channel extending through said handle and said cutting head,
said knife affixed to said cutting head, said cutting head
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having a notch extending along an outer surface of said
cutting head, said knife received within said notch; and a
locking member rotatably mounted onto said cutting head,
said locking member movable between a first position
overlying said knife so as to lock said knife within said
notch and a second position offset from said knife so as to
allow removal of said knife from said notch.
According to another aspect of the invention,
there is provided a device for stripping a cable comprising:
a body having a channel extending therethrough, said body
having a narrow end, said channel opening at said narrow
end, said channel having a longitudinal axis, said body
comprising: a handle; and a cutting head affixed to an end
of said handle, said channel extending through said handle
and said cutting head, said cutting having a cutout area at
said narrow end so as to extend inwardly of said channel
from the narrow end; and a knife affixed to said cutting
head, and extending along a notch formed on an outer surface
of said cutting head, said knife being fixedly received
within said notch, said knife having a blade with a cutting
edge extending upwardly into said channel through said
cutout area, said blade extending at an angle not transverse
to said longitudinal axis.
According to another aspect of the invention,
there is provided a method of stripping a sheathing from a
cable in an anchor of a post-tension anchor system, the
anchor having a tapered bore, the cable extending into the
tapered bore, the method comprising: a tool having a
channel extending therethrough with a knife affixed thereto
and having a blade extending into said channel, said tool
having a longitudinal axis, said blade being angularly
offset to a transverse of said longitudinal axis; inserting
said tool into the tapered bore of the anchor until said
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knife engages the sheathing of the cable; rotating the tool
around the cable such that said knife draws said tool
further into said tapered bore until an outer surface of the
tool abuts the tapered bore and cannot move further into the
tapered bore; squeezing said tool so as to compressively
contact the sheathing exterior of said tapered bore; and
pulling the tool from the tapered bore so as to remove a cut
section of the sheathing from the tapered bore.
BRIEF DESCRIPTON OF THE DRAWINGS
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FIGURE 1 is a perspective view of the device in accordance with the preferred
embodiment
of the present invention.
FIGURE 2 is a plan view of the device in accordance with the preferred
embodiment of the
present invention.
FIGURE 3 is an isolated end view of the handle used in the present invention.
FIGLRE 4 is a cross-sectional view of the handle as used in the present
invention.
FIGURE 5 is an opposite end view of the handle as used in the present
invention.
FIGURE 6 is a bottom view of the cuttina head as used in the present
invention.
FIGURE 7 is a plan view of the knife as used in the present invention.
FIGURE 8 is a side view of the I:nife as used in the present invention.
FIGURE 9 is an end view of the knife as used in the present invention.
FIGURE 10 is a cross-sectional -view showing the assemblv of the present
invention.
FIGURE 11 is a cross-sectional view showing the projections formed within the
channel
associated with the handle of the present invention.
FIGURE 12 illustrates the method of the present invention in which the tool is
inserted into
the tapered passage of an anchor.
FIGURE 13 is an illustration of the method of the present invention in which
the tool is
rotated so as to be in its terminal position within the interior of the
anchor.
FIGURE 14 is an end view showing the manner in which the tool of the present
invention cuts
through the sheathing of the cable.
FIGURE 15 is a diagrammatic illustration of how the tool of the present
invention serves to
draw the tool within the anchor bodv and to cut the sheathing from the cable.
DETAILED DESCRIPTION OF THE PRESEIv'T INVENTION
Referring to FIGURE 1, there is shown at 10 the tool in accordance with the
teachings of the
present invention for the stripping of sheathing from a cable of a post-
tension anchor system. The
tool 10 has a body 12 having a channel 14 extending therethrough. The body has
a narrow end 16
at one end thereof. A knife 18 is a$~i,ed at the narrow end 16 of the body 12.
Knife 18 has a cutting
edge extending at an acute angle relative to the Iongitudinal axis of the
channel 14.
In the present invention, the body 12 includes a handle 13 and a cutting head
15. The cutting
head 15 is removablv affuced to an end of the handle 13. The handle 13 is
formed of a flexible
polvmeric material. The handle 13 is desirably compressible so as to reduce
the size of the channel 14
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upon an application of a squeezing force onto the exterior surface of the
handie 13. The channel 14
extends through the interior of the handle 13 so as to have one end opening at
the narrow end 16 of
the cutting head 15 and an opposite end 20 opening at the end 22 of the handle
13. The channel 14
should have a sufficient width and depth so as to accommodate the size of the
cable vvhich is to be
stripped. In particular, the width of the channel 14 should be sufficient so
that the cable, along with
its sheathinQ, can be easily placed within the channel 14. As can be seen in
FIGURE 1, projections
17 extend from the handle 13 into the channel 14. Projections 17 are,
desirably, ribs which extend
longitudinalh= along the channe114. These projections 17 ea-tend inwardlv into
the channel 14 so as
to allow the user to properly squeeze the handle 13 so as to apply a
compressive force onto a cable
received within the channel 14. The projections 17 will grasp or engage the
sheathing so as to
facilitate the ability of the user of the tool 10 to remove the sheathing from
the underl,ving tendon.
The body 12 has a constant diameter portion 24 and a tapered portion 26. The
constant
diameter portion 24 has a knurled surface 28 formed thereon. The knurled
surface 28 facilitates the
abilitv to properly rotate the too110 around the exterior of a cable within
the channel 14. The tapered
portion 26 narrows in diameter from the constant diameter portion 24 to the
narrow end 16. The
tapered portion 26 should have a size which is less than the size of the
tapered passage within the
anchor into which it is to be inserted. Generally, the angle of taper of the
tapered section 26 will
match the angle of taper of the tapered bore within the anchor. In actual use,
the cable can simply
be inserted into the channel 14 by placing the tool 10 over the cable. As
such. the present invention
avoids the problems associated with "threading" the cable through a tubular
interior of the tool 10.
T'he tool 10 is suitable for use in association with any sort of anchorages,
including intermediate
anchorages.
As can be seen in FIGURE 1, the knife 18 extends across a portion of the
bottom 30 of
channel 14. The knife 18 is located at the narrow end 16 of the cutting head
15. As will be described
hereinafter, the blade of the knife 18 is configured so as to facilitate the
ability to insert the tool into
the tapered bore of the anchor and to facilitate the ability to properly cut
the cable. The knife 18 may
be forrned of a stamped steel material. W-ithin the concept of the present
invention, it is not necessary
to machine the cutting edge of the blade of knife 18 since it is not necessary
for the cutting edge of
knife 18 to "plow" through the plastic sheathing of a cable.
FIGURE 2 shows a plan view of the tool 10. As can be seen, the channel 14
extends
longitudinally through the body 12. The channel 14 has one end opening at end
22 of the handle 13.
The channel 14 has an opposite end opening at the narrow end of the cutting
head 15. The
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channel 14 has a generally constant width extending along its length. The body
12 has a constant
diameter portion 24 and a tapered portion 26. The tapered portion 26 extends
from the constant
diameter portion 24 to the narrow end 16. A cutout area 32 is positioned at
the narrow end 16 of the
bodv 12. Cutout area 32 has knife 18 extending therethrough. Cutout area 32
allows the blade of
the knife 18 to be extended into the channel 14. lyv'hen the knife 18 is
affi,ted onto the cutting
head 15 of the bodv 12 it is in a rigid and fLxed non-movable condition.
As can be seen in FIGURE 2, the knife 18 is positioned so as to extend through
the cutout
area 32 on the narro", end 18 of the cutting head 15. The blade of knife 18 is
illustrated as formina
an acute angie with respect to the longitudinal axis of the channel 14.
Ideally, within the concept of
the present invention this acute angle should be between 70 and 89 degrees
with respect to this
longitudinal axis. Altetnativeh, stated_ this acute angle should be between 1
and 20 degrees with
respect to a transverse of this longitudinal axis. This arrangement is
described hereinafter in greater
detail.
FTGURE 3 shows the end 22 of the handle I3. As can be seen the handle 13 has a
generally
circular configuration with the channel 14 extending thereinto. Receiving
holes 33 and 35 are formed
interior of the handle 13 so as to facilitate the attachment of the cutting
head 15 onto the handle 13.
In FTGLJRE 3, it can be seen that the handle 13 has projections 37 extending
thereinto. These
projections 37 are, preferablyl, in the fotm of tibs extending longitudinally
alona the channel. 14.
However, and alternatively, these projections 37 can be in the nature of pins,
a knurled surface,
dimples, or ribs which extend transverse to the lonaitudinal axis of channel
14. These projections 37
facilitate the ability to squeeze the handle 13 and engage the sheathina of
the tendon extending
therethrough. As such_ this confiauration of the handle 13 faciiitates the
abilitv to remove the
sheathing from the underiving tendon.
FIGUR.E 4 shows a cross-sectional view of the handle 13. It can be seen that
the channel 14
ea-tends through the interior of the handle 13. The structure of the handle 13
is assured bv the
fotmation of the interior surface 39. The cutting head can be received within
the openinQ 41 located
at end 43 of the handle 13. Suitable fastener members can be received through
the hole 33 formed
in the section 39 of handle 13.
FIGURE 4 shows the opposite end 43 of the handle 13. Projections 37 are
illustrated as
extending along the inner surface of the handle 13 witliin the channel 14.
FIGUR.E 6 is a detailed view showins the attachment of the cutting head 15 to
the handle 13.
The cutting head 15 can be formed of a rigid steel material and is suitablv
fastened by bolts, pins,
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rivets or other means within the end 43 of the handle 13. The cutting head 15
includes a connector
section 45 and a tapered section 47. A notch 49 is formed in the tapered
section 47 and extends to
the cutout area 32. Notch 49 has a pin 51 formed therein at an end of the
notch 49 opposite the
cutout area 32. The pin 51 is desimed so as to receive a hole formed in a
blade fastened within the
notch 49. A locking member 53 is rotatably mounted at point 55 onto the
straight section 45 of the
cutting head 15. The locking member 53 is rotatable between a first position
(illustrated in
FIGURE 6) which allows for a removal of the knife from the notch 49 to a
closed position in which
the outwardlv extending surface 57 of the locking member 53 will overlie the
end of the knife 18
received within the notch 49 so as to fixedly "lock" the knife in its position
within the notch 49. The
locking, member 53 can be mounted on point 55 so as to be rotatable
therearound. Locking
positioners 57 and 59 are provided on the straight section 45 of cuiting head
15 so as to retain the
locl:ing member 53 in its locl:ing position over the pin 51 and over the knife
received within slot 49.
FIGURE 7 is an isolated view of the knife 18. As can be seen, the knife 18 has
a blade 61
at one end thereof. A hole 63 is formed adjacent to the opposite end 65 of the
knife 18. The knife
18 will have a size suitable for receipt within the notch 49. The blade 61
will extend upwardly
through the cutout area 32 when the knife 18 is received within the notch 49.
The hole 63 will be
of a sufficient diameter to fit onto the pin 51. When the knife 18 is received
within the notch 49, the
locl:ing member 53 can be suitably rotated so that the surface 57 overlies the
end 65 of the knife 18
and overlies the pin 51 and the portion of the knife 18 received thereon.
In FIGURE 7, it can be seen that the blade 16 extends at an angle "c" with
respect to the
longitudinal axis of the knife 18 and/or the longitudinal axis of the channel
14. Angle "c" is between
70 and 89 degrees. In the preferred embodiment of the present invention, this
angle "c" will be
between 85 and 87 degrees. If the blade 61 were transverse to the longitudinal
axis of the knife 18,
then it would not create the desired cutting pattern for drawing the knife
inwardly into the bore of the
anchor nor would it effectively cut the tendon. As such. the broadest term to
express the angle "c"
would be that the blade 16 is arranged in non-transverse relationship to the
longitudinal axis of the
channel 14.
FIGURE 8 shows a side view of the knife 18. As can be seen, hole 63 is
positioned adjacent
to the end 65 of knife 18. The knife 18 includes a portion 67 which extends
upwardly from the end
section 69 by an angle a. This angle a is, in the preferred embodiment of the
present invention,
between 6 and 7 degrees. This angle a will follow the angle of taper
associated with the tapered
section 47 of the cutting head 15. The blade 61 has a cutting edge 71 at an
end opposite to a bottom
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9
surface 73 of the blade 16. The blade 61 extends upwardh, from the section 67
of kni.fe 18. The
blade 61 will extend inwardly at an angle (', with respect to the vertical.
Artgle P is, in the preferred
embodiment of the present invention. twenty-five degees (25 ). Tl-us angle ~i
assures that the cutting
edUe 71 of blade 61 aill engage the sheathi.rt-a of the tendon and rvill serve
to draw the knife 18 along
the sheathing.
FTGLTRE 9 shows an end tiiew of the I:nife 18 and showing in particular. the
blade 61. It can
be seen that the cutting edae 71 extends at an an-aJe with respect to the
bottom surface 73. The ange
of the cuttirta edge 71 is appro~imately fifteen degrees (15'') e%tendirtg
from an initial engagement
point 75 to the lower edge 77. The enaagement point 75 is a sharp point which
will help to penetrate
the sheathina Then the tool 10 is initiallv inserted into the cavitv of the
anchor.
FIGURE 10 is a cross-sectional tiiew showina the manner i.n which the cutting-
head is joined
to the handle 13. As can be seen, a screw or bolt 79 serves to secure the
rearward portion of the
cutting head 15 onto the end 43 of the handle 13. In FIGU-R.E 10, it can be
seen that the cutting
head 15 has loclcing member 53 mounted onto pivot point 55. The locl;inQ
member 53, as shown in
its locking position, is particularh iIlustrated in FIGURE 10. As can be
seen, the surface 57 of the
locking member 53 overlies the end of the knife 18 located within its channel.
Al.so, the hole 63 of
knife 18 is positioned over pin 51. As a result, the lstife 18 is fixedly
retained within the notch 49 so
that the blade 61 will extend upwardly into the cutout area 32 at the end of
the cuttina head 15. This
arrangement facilitates the ability to form the l:rtife 18 of a simple stamped
steel material. The
positioning of the knife 18 within the notch 49 assures lonQitudinal rigidit-Y
of the knife 18. Althoueh
ti,e- individuaI l:iiives 18 are of a ver}r "flimsv"' materiai, the
arrangement of such a knife 18 in its notch
49 tui-ns such flimsy materiaI into a rig:id cunina tool. Ihis ri ~din7
assures that the blade 18 will have
sufficient strength and non-deflectability so as to cut the tough sheathing
associated with the cable.
At the time that the worker should decide that the krtife 18 and its
associated blade 61 have
become too dull to further cam, out simple cutting activities, the l:nife 18
can be removed by simply
rotati.rtg the locking member 53 so that the locl<ina member 53 is in its
releasing position (shown in
F1(DrUP.E 6). The I:nife 18 can be simpl}' lifted from the notch 49 and
replaced with another krtife 1. 8.
The locl:ina member 53 can be then rotated to the position shown in FIGU-RE 10
so that the worker
can easily resume hi.s cutting activiiies. As such, the l:nife 18 can be
easih= replaced without the need
for aulilian- tools.
FIGURE 1.1 shows the interior of the channel 14 formed in the handle 13. As
can be seer
projections 37 e:.'tend lon-,~tudinalh along the channel 14. These projections
37 are illustrated. in the
CA 02616773 2008-01-22
WO 00/12244 PCT/US99/18937
preferred embodiment of the present invention, as small ribs extending along
the length of the handle
13. Since the handle 13 is formed of a flexible polymetic material, the worker
can exert sufficient
squeezing force onto the exterior of the handle 13 so that the projections 37
engage the sheathing of
the cable. ~Ls such, after the sheathing has been effectivelv cut within the
anchor, the worker can
squeeze the handle 13 so as to grasp the sheathing and to pull the sheathing
from the underlving
tendon. This arrangement will avoid any undue forces upon the blade 61 and
will facilitate the
removal of the sheathing from the underlying tendon.
FIGURES 12 - 15 show the manner in which the tool 10 can be used for the
stripping of
sheathing 50 from a cable 52. As dlustrated in FIGLJRE 12, the cable 52 has
its sheathing 50
eztending therearound. The cable 52 extends through the interior of an anchor
54. The anchor 54
has a tapered bore 56 suitable for the receipt of wedges therein. The anchor
54 which is illustrated
is of a conventional configuration.
As can be seen in FIGURE 12, the tool 10 has body 12 extending around the
exterior of the
cable 52. The tool 10 is positioned generally outwardh, of the tapered bore 56
relative to anchor 54.
The blade of knife 18 is positioned in close proximity to the sheathing 50 of
the cable 52.
So as to initiate the proper cutting of the sheathing 50 from the cable 52, it
is necessary to
insert the tool 10 into the tapered bore 56 of anchor, 54. This arrangement is
illustrated in
FIGURE 13. Initially, the tool 10 is inserted so that the tapered portion 26
of body 12 resides within
the tapered bore 56. The constant diameter portion 24 of the too110 should be
gripped by hand and
pushed into the tapered bore 56 as far as possible. At such a point, the
cutting edge of the blade of
knife 18 will engage the sheathing 50 of cable 52.
The workman can then rotate the tool 10 in a suitable direction so that the
cutting edge of the
blade of knife 18 will cut further into the sheathing. The tool 10 should
continue to be rotated such
that the angled relationship between the blade of knife 18 and the
longitudinal axis of the body 12 of
tool 10 causes the tool 10 to be drawn further into the tapered bore 56. It is
only with this angIing
of the blade of the knife that the "drawing inward" effect is achieved. The
tool 10 should continue
to be rotated until the exterior of the tapered portion 26 of tool 10 strongly
abuts the walls of the
tapered bore 56 of anchor 54. At such a point, the tool will not be drawn in
anv further. As a result,
the angled arrangement of the blade of knife 18 will simply cut transversely
through the sheathing 50.
After sufficient cutting has occurred, the flexible handle 13 of the tool 10
should be compressively
grasped so that the projections on the channel 14 engage the sheathing 50.
After the handle 13 has
been squeezed, the tool 10 can be pulled outwardly from the tapered bore 56 of
anchor 54 so that
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WO 00/12244 PCT/US99/18937
11
the sheathing 50 can be pulled from the cable 52. As can be seen in FIGURE 13,
this sheathing is
separated from the steel wires fiich form the tendon. As the tool 10 is moved
rearwardly, the
sheathing 50 is separated from the underlying tendon.
FIGURE 14 shows how the cutting blade 61 extends into and cuts through the
sheathing 50
of cable 52. Additionally, FIGURE 14 shows the manner in which the handle 13
can be squeezed
so that the channel 14 engages the sheathing 50 of cable 52.
In FIGURE 15, it can be seen how the blade of l:nife 18 forms its incision
into the sheathing
50 of cable 52. As can be seen, the rotation of the tool 10 creates a spiral
pattern of incision 62
through the sheathing 50. When the tool 10 reaches its terminal portion within
the tapered bore 56,
the continued rotation of the tool 10 creates a transverse cut 64. The
sheathing 50 can be separated
from the steel wires 66 in the area of the cut 64. Portion 68 can be simpIy
pulled away from the
section 70 so as to separate the sheathing 50.
Unlike the prior art, the present invention requires no hammering. Since there
is no "plowing"
effect caused by the knife edge, there is no need to create a sharp machined
steel carbide cutting edge.
The knife can be simply affixed onto the end of the tool. There is no need for
a pivoting arm of the
type described in U. S. Patent No. 5.632,088. The rotation of the tool 10
assures that the tool
"bottoms out" within the tapered bore. As such_ the problem of sheathina
remaining in the area of
the wedges is effectivel-v avoided. The length of the tapered section will be
identical to the length of
the exposed tendon desired for use in conjunction with the wedges. The channel
which opens to the
exterior of the bodv of the tool allows the tool to be easily placed over the
cable rather than threaded
along the cable. The use of the polymeric material for the handle 13 can be
fonned by injection
molding processes so as to provide a relatively inexpensive and more effective
handle. The stamping
of the l:nife, as used in the present invention, assures that a relatively
inexpensive l:nife is provided.
The foreQoing disclosure and description of the invention is illustrative and
explanatory
thereof. Various changes in the details of the illustrated apparatus or in the
steps of the described
method can be made within the scope of the appended claim.s without depanina,
from the true spirit
of the invention. The present invention should onlv be limited by the
following claims and their legal
equivalents.
