Note: Descriptions are shown in the official language in which they were submitted.
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~u~ G JIG FOR COLLAPSIBLE CYLINDRICAL PRODUCTS
This invention relates to cutting jigs for collapsible
cylindrical products.
Various cylindrical products require cutting to desired
5 lengths or to have their ends cut at desired bias or mitre
angles to suit their particular requirements. To provide these
results, cutting problems do not normally arise unless a
cylindrical product is radially collapsible under a cutting
blade or is already collapsed inwardly out of its cylindrical
10 configuration before cutting commences. One example of such
a collapsible product is foam insulation tube as may be used
for fitting around fluid flow pipes, e.g. water pipes, for
thermal insulation purposes.
Foam insulation tube may collapse radially inwards and
15 may even crease away from its true cylindrical shape. To
provide satisfactory results which not only appeal to the eye
by providing the look of a professionally fitted thermal
insulation around flow pipes, but also provide a fully
efficient thermal insulation construction, it is essential for
20 successive lengths of foam insulation tube to be abutted
cleanly with no gaps. When the path taken by a fluid flow
pipe is substantially straight, successive foam insulation
tube lengths need to have planar cut end surfaces which are
normal to the axial direction of the lengths. Alternatively,
25 when flow pipes join at 45 degrees or 90 degrees, each cut
length of foam insulation tube requires to have respectively,
a 22.5 degree or a 45 degree mitre. In addition, to this,
other cuts may be necessary to provide a snug fit for foam
insulation tube. In one particular construction at a "T"
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junction, a "V"-shaped notch is required to be cut into the
side of the tube providing the head of the junction. A
corresponding symmetrically tapered cut end is required for
the tube forming the leg of the "T" junction so as to fit
5 properly into the notch. In another example, a three sided
notch forming three sides of a rectangle is required in the
insulation to receive one edge of a structural member where
a flow pipe is secured to the member. Because foam insulation
tube is readily collapsible under pressure of a cutting blade
10 or may have already assumed a collapsed state before cutting
commences, it may be extremely difficult or even impossible
to provide properly executed cuts in the forms discussed
above. As a result, satisfactory abutting together of foam
insulation tube lengths may be difficult to obtain without
15 leaving gaps which detract from the heat exchange efficiency
of the total insulation. Indeed, unsatisfactorily abutted
insulation tubes may even result in wastage of tubing.
It is essential to realise that foam insulation tube may
be usefully employed around flow pipes for cold fluids as well
20 as for warm or hot fluids. Flow pipes for transporting cold
fluids present cold outer surfaces upon which condensation
forms in humid atmospheres. Not only does such condensation
tend to drip onto floors and articles beneath, which can be
destructive, but it encourages growth of mold and fungus upon
25 condensate-contacted surfaces. In such environments, foam
insulation tube effectively acts as a vapour barrier around
such flow pipes. However, condensation may still form upon
exposed surfaces of flow pipes for containing cold fluids
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when foam insulation tube lengths do not abut properly but
leave gaps.
The present invention seeks to provide a cutting jig for
collapsible cylindrical products and which may be used to
5 minimize or avoid the above problems.
According to one aspect, the present invention provides
a cutting jig for a collapsible cylindrical product comprising
a channel for accommodating the product, the channel having
an inner surface profile provided at least partly by a
10 plurality of at least four product support surfaces comprising
opposed side surfaces, and inclined surfaces extending
downwardly and inwardly of the side surfaces, respectively,
the channel provided with a pair of aligned guide surfaces for
guiding a cutting tool on cutting strokes with the tool
15 extending across the channel.
As may be seen, a cutting jig according to the invention
not only has side surfaces but also has inclined surfaces
which extend from the side surfaces. Thus the cylindrical
product which is to be cut is supported in more positions
20 around its lower periphery, and in locations which are more
closely positioned together than would be the case if either
a conventional mitre block or Vee block were used. The jig
does therefore tend to maintain the product in, or restore it
to, its cylindrical form around its lower regions and as a
25 result tends to stiffen the upper regions through which the
cutting blade will initially pass.
For the product to be supported around its lower
periphery in a truly cylindrical configuration, the product
support surfaces should preferably all form tangents to a
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common circle equal to the diameter of the outer periphery of
the cylindrical product. In a preferred embodiment of the
invention, the inner surface profile of the channel has a
single inclined surface extending between each side surface
5 and a base surface and with this structure, the profile
provides five support surfaces the base surface and inclined
surfaces of which provide part of an octagonal shape.
Alternatively, two or more inclined surfaces are provided
between each side surface and the base surface with each of
10 the inclined surfaces also forming tangents to the common
circle. It follows that the support positions for the lower
regions of the product increase as the number of inclined
surfaces increase and, correspondingly, the distances between
these support positions decrease.
A single inclined surface may be provided by a single jig
element extending along the jig and between each base surface
and a side surface. Alternatively, a plurality of coplanar
inclined surfaces may be provided between each side surface
and the base surface, these coplanar surfaces provided by a
20 plurality of spaced apart corner members with certain of the
corner members located specifically to provide support for the
product adjacent to the pair of guide surfaces.
A plurality of pairs of aligned guide surfaces may be
provided to provide a variety of alternative mitre angles at
25 the ends of insulation tube and/or to provide different shapes
for these ends. In such a particular structure, the plurality
of corner members are located adjacent to each cutting
position so as to hold the product in a substantially
cylindrical condition for any particular cutting action.
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Where corner members are used for providing the guide
surfaces, in a practical construction the channel has two side
walls extending downwards to, and secured to, a base. The
side walls and the base provide, respectively, the side
5 surfaces and base surface of the inside surface profile.
In a particularly preferred arrangement, the channel of
the jig, as discussed above, also provides a support channel
for an insert channel providing a part of the jig. The insert
channel is insertable in nesting relationship within the
10 support channel for accommodating a collapsible cylindrical
product which is smaller in diameter than the product to be
accommodated by the support channel. The insert channel also
has an inner surface profile provided at least partly by a
plurality of support surfaces for the smaller diameter
15 product. These support surfaces include opposed insert side
surfaces, an insert base surface and an insert inclined
surfaces depending one from each side surface. The insert
also has aligned guide surfaces which, when the insert channel
is inserted into the support channel, are aligned with the
20 guide surfaces of the support channel for guiding the cutting
blade on its cutting strokes. A registration means may be
provided for insertion of the insert channel into the support
channel so as to locate the insert channel only in one
position of orientation and longitudinal location along the
25 support channel. Preferably, the cross-sectional shape of the
smaller insert channel is similar to that of the first insert
channel.
In a further preferred construction, another and smaller
insert channel is provided which is insertable in nesting
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relationship within the insert channel referred to above. The
smaller insert channel is to be used for cutting collapsible
cylindrical product which is smaller in diameter than the
product to be accommodated and cut within the larger insert
5 channel.
According to a further aspect, the present invention
provides a cutting jig for a collapsible cylindrical product
comprising a channel for accommodating the product, the
channel having an inner surface profile provided at least
10 partly by a concave support surface, the channel provided with
a pair of aligned guide surfaces for guiding a cutting tool
on cutting strokes with the tool extending across the channel.
The cutting jig according to the above further aspect has
similar advantages to the cutting jig defined according to the
15 invention of the first aspect, as above.
The invention also includes a kit of cutting jigs. In one
arrangement of the kit, each cutting jig comprises a channel
having an inner surface profile provided at least partly by
a plurality of at least four product support surfaces
20 comprising opposed side surfaces and inclined surfaces
extending downwardly and inwardly of the inclined surfaces.
In another arrangement of the kit, each cutting jig comprises
a channel having an inner surface profile, provided at least
partly by a concave support surface. In both kit
25 arrangements, each channel is provided with a pair of aligned
guide surfaces for guiding a cutting tool on cutting strokes
with the tool extending across the channel.
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Embodiments of the invention will now be described, by
way of example, with reference to the accompanying drawings,
in which :-
Figures la to le are perspective views showing different
5 types of joints required of foam insulation tubing and as maybe provided using a cutting jig of any of the embodiments;
Figure 2 is an exploded isometric view of a cutting jig
of a first embodiment;
Figure 3 is an end view of the exploded cutting jig of
10 the first embodiment;
Figure 4 is a plan view of a part of the jig of the first
embodiment;
Figures 5 and 6 are views similar to Figure 4 of other
parts of the jig of the first embodiment;
Figure 7 is a side view of a channel forming the largest
part of the jig of the first embodiment and showing foam
insulation tube accommodated in the channel and ready for
cutting;
Figure 8 is a cross-sectional view through the channel
20 of Figure 7 taken along line 'VIII-VIII' in Figure 7;
Figure 9 is an isometric view on one side of the channel
of Figure 7 and showing use of the channel for providing cut
ends for the tube length structure of Figure la;
Figures 10 and 11 are views similar to Figure 9 and
25 showing use of the channel for providing cut ends for the tube
length structures, respectively, of Figures lb and lc;
Figures 12, 13 and 14 are each similar to Figure 9, the
Figures showing stages in providing cut surfaces for the tube
length structure of Figure ld;
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Figures 15, 16 and 17 are views similar to Figure 9, the
Figures showing stages in providing a cut notch for the tube
length structure of Figure le;
Figure 18 is a perspective view showing a type of joint
5 required of foam insulation tubing and similar to the cut
notch structure of Figure le;
Figure 19 is a view similar to Figure 9 and showing use
of the channel of Figure 7 for cutting the cut notch structure
of Figure 18;
Figures 20 and 21 are views similar to Figures 7 and 8,
respectively, and showing an assembly of the largest part of
the jig of the first embodiment with an insert channel in
position and carrying foam insulation tube of smaller
diameter;
Figure 22 is an end view of an exploded cutting jig of
a second embodiment; and
Figures 23 and 24 are end views of cutting jigs forming
kits of cutting jigs according to third and fourth
embodiments.
A cutting jig of the first embodiment to be described may
be used to form any of the joints or abutting end
configurations for foam insulation tube as shown in any of
Figures la to le.
As shown in Figure la, a fluid flow pipe in the form of
25 a water pipe 10 is surrounded by foam insulation comprising
lengths 12 of foam insulation tube which are abutted end to
end. Ends of the tube lengths 12 are cut normal to the
lengths of the tubes with adjacent ends 14 abutted close
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together in intimate contact without formation of noticeable
gaps between these ends.
In other Figures lb to le, the abutting ends of lengths
12 of insulation also have no gaps formed between them through
5 which heat could be transferred to or from the water pipes
shown in those Figures. Avoidance of gaps also prevents
formation of condensation with its attendant mold, fungal and
other problems caused by damp.
In Figure lb, a right hand junction is formed between two
10 water pipes 14 and 16 which necessitates two tube lengths 12
having ends 18 cut at a mitred angle of 45 degrees to the axes
of their respective lengths. In Figure lc two water pipes 19
extend one from the other at an obtuse angle of 135 degrees.
This necessitates the abutting tube lengths 12 having abutting
15 ends 20 at the bent position, each end 20 being cut at 22.5
degrees to the longitudinal axis of its length 12.
As shown in Figure ld, a "T" joint is provided between
a water pipe 21 forming the head of the "T" and water pipe 22
extending downward from it. In this arrangement a length 23
20 of foam insulation tube requires a "V" shaped notch formed
into it with tapering sides 24 generating a right angle at the
junction between them. A length 26 of foam tube for location
around the pipe 22 is required to be formed with a tapered end
having sides 28 complementary in angle to the sides 24 for
25 abutting purposes.
Finally, in Figure le a water pipe 30 extends beneath a
structure comprising beams 32, which might be wood or metal,
(one only being shown) to which the pipe is secured by
suitable brackets. Foam insulation tube lengths 33
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surrounding the pipe 30 need to pass beneath each of the beams
32 and in doing so require to be cut at the one side with a
three sided notch 34 for accommodating the beam. The fit of
the beam 32 within the notch avoids any undesirable gaps which
5 may allow for heat transfer to or from the water pipe 30.
In the embodiment as shown particularly in Figures 2 and
3, a cutting jig 40 is provided for cutting the various end
shapes to foam insulation tube lengths 12 shown in Figure la
to le. The jig 40 comprises a channel 42 which provides a
10 support channel for a first insert channel 44. The channel
44 is the larger of two insert channels, the smaller insert
channel being channel 46.
The support channel 42 comprises two side walls 48 and
a base 50 secured between the side walls with the side walls
15 extending upwardly from the base in spaced apart relationship.
The channel 42 is provided with a product support surface
profile, i.e. for supporting foam insulation tube lengths.
This profile comprises two side surfaces 51 provided by the
side walls 48 and a base surface 52 which faces upwardly
20 between the side walls. The distance between the side
surfaces 51 corresponds to the outside diameter of a foam tube
length 12, 23 or 26 (Figures lc and ld), so that the tube
length will fit snugly between the side walls while supported
upon the base surface 52. The support surface profile also
25 includes inclined surfaces 54 between the base surface and the
side surfaces. These inclined surfaces 54 are provided upon
corner members 56 which are of suitable triangular shape to
fit into the corner formed between and a corresponding side
wall 48 and the base 50 of the channel 42. The corner members
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56 may be formed integrally with the channel 42, perhaps as
a unitary molding.
As shown particularly by Figure 2, the corner members 56
and thus the surfaces 54 between each side wall and the base
5 are spaced apart longitudinally of the channel with the
surfaces 54 lying in a single inclined plane. Thus,
effectively, a single inclined surface extends between each
side wall and the base. The inclined surfaces 54 together
with the base surface 52 and the side surfaces 51 form
10 tangents to a common circle substantially equal in diameter
to that of a length 12, 23 or 26 of foam insulation tube which
is to be accommodated in the channel thereby supporting the
lower part of the tube in its substantially cylindrical
condition. As an alternative to the individual corner
15 members 56, single fillet members (not shown), having a
triangular section, may extend from end to end of the channel
42, one between each side wall 48 and the base 50 so as to
provide a continuous inclined support surface throughout the
length of the channel.
As shown in Figures 2 and 4, the channel 42 has its side
walls 48 formed with pairs of aligned guide surfaces for
guiding a cutting blade on cutting strokes to be performed
upon a length of foam insulation tube. A first pair of
aligned guide surfaces is provided by aligned slots 60 which
25 extend downwardly into the side walls 48, the slots 60 being
joined together by a slot 62 which is formed into the surface
52 of the base member. The slots 60 and 62 are formed at a
mitre angle of 45 degrees to a longitudinal axis of the
channel 42. Similarly a second pair of guide slots 66 in the
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side walls 48 and inclined at a mitre angle of 67.5 degrees
to the longitudinal axis of the channel are joined together
by a further slot 68 in the base surface 52 so as to provide
straight line cutting guides at that required angle.
In addition, as shown by Figure 2, but more particularly
by Figure 7, laterally aligned "V" notches 70 are provided in
the side walls 48, towards one end of the channel 42. Each
notch has downwardly inclined sides 72 which meet at a right
angle, as shown by Figure 7. The junction point 74 of the
10 sides 72 lies substantially at the same vertical height from
the base surface 52 as the longitudinal axis 76 for lengths
of foam tubing which are to be cut in the channel 42. At the
other end of the channel 42, the two side walls have aligned
notches 78 which follow a rectangular configuration which is
15 open at that end of the channel. Each notch 78 is provided
by a downward edge surface 80 in each side wall 48 and a
horizontal edge surface 82. The two edge surfaces 82 coincide
in height from the base surface 52 to the uppermost extremity
of the inner peripheral surface of a length of foam insulation
20 tube which is to be cut within the channel 42.
As will be noticed, particularly from Figure 4, the
corner members 56 are spaced apart as already stated above,
but are located in positions such as to support foam
insulation tube lengths in locations close to any cutting
25 operation which may be performed using any of the guide
surfaces provided by the channel 42.
The channel 42 may be used alone without either of the
inserts 44, 46 for cutting foam insulation tube lengths of a
specific diameter.
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As shown in Figures 7 and 8 with a tube length 12
disposed in cylindrical form within the channel 42, the side,
base and inclined surfaces 51, 52 and 54 engage and support
the outer peripheral surface of the tube length around its
5 lower regions.
During any cutting action which is to follow, the support
provided around lower regions of the tube length to hold it
in cylindrical shape stiffens these lower regions and, in
consequence, tends to hold and stiffen the upper regions which
10 are not so supported. Thus resistance to collapse of the
upper regions is provided thereby enabling, with a careful
cutting action of a sharp blade, the provision of a precisely
cut end shape to the tube length.
The cutting blade (not shown), which may be a sharp
15 knife or a saw, may be used to cut downwards along the guide
surface line 83 offered by the end 84 of the channel (see
Figure 9) to provide a cut end 14 for abutting length ends as
shown in Figure la. Cutting downwards with a knife inserted
as shown in Figures 10 and 11, respectively, into slots 60 or
20 66 and continuing down along cutting lines 85 and 87 into the
grooves 62 or 68 respectively, will provide cut ends 18 and
20 for use in the type of abutting relationship of the lengths
12 shown in Figures lb and lc respectively.
Alternatively, where a "V" notch with sides 24 is to be
25 provided as shown in Figure ld, the cutting blade is cut
downwardly into the tube length 23 while being guided by the
pair of guide surfaces 72 (see Figure 12). The tube length
23 is of conventional construction in that it has a
longitudinal slit 88 to enable it to be opened for positioning
13
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around the pipe 21. For the cutting of the notch with sides
24, the tube length 23 is placed in the channel 42 with the
longitudinal slit upwards so that the notch is cut downwards
into the tube length from both sides of the slit. The bottom
5 of the notch corresponds to the junction positions 74 and
which are thus disposed at opposite ends of the tube diameter.
The tube length 23 is then removed and the tube length 26
placed into the channel. The tube length 26 is then trimmed
at its end to provide the tapered end with sides 28 by first
10 cutting down into the slot 60 along cutting line 85 as
discussed above to provide a planar end surface 18 mitred at
45 degrees on the tube length. The tube length is then
rotated by 180 degrees at the same longitudinal position in
the channel and the cutting process is repeated. The repeat
15 cutting process will only cut through part 86 of the end
region of tube (Figure 14) to provide the required tapered end
with surfaces 28. The intersection point between the grooves
62 and 68 lies upon the median plane of the channel. After
the tube length 26 has been rotated, and prior to the repeat
20 in the cutting process as shown by Figure 114, the correct
position of the tube length 26 for the repeat cutting process
is when the end surface 18 crosses the intersection point
between the grooves 62 and 68.
When it is required to cut a three sided notch 34 (Figure
25 le) a tube length 33 is cut radially. For this, two cuts 90,
spaced apart and corresponding to the width of the beam 32,
are made using the guide surface 80 (Figure 15). The blade
is then urged downwards in inclined fashion (for instance as
shown by the curved direction arrow in Figure 16) to the guide
14
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surfaces 82. The blade then cuts along the tube using the
guide surfaces 82 for blade positioning. This provides a
partially finished base surface 88 for the notch 34, the
surface having an upwardly inclined end as shown by Figure 16.
5 The cutting blade is then guided in the opposite direction,
i.e. towards the right in Figure 17, along guide surfaces 82
until the blade reaches the guide surfaces 80. This action
removes the upwardly inclined end of the base surface 88 to
give a completely planar base surface 88, thereby completing
10 the notch 34.
Should a notch be required which is longer than the
lengths of the guide surfaces 82, then this may be
accommodated by the channel 42. This may occur, for instance,
when a building has a wider beam 32a such as provided by three
15 beams 32 nailed together side-by-side (Figure 18). A
sufficiently long notch 34a must be formed to correspond to
the width of the beam 32a. For this long notch formation, the
notch 34 as discussed above is made longer. This is easily
performed (Figure 19) by placing the cutting blade 91 upon the
20 base surface 88 with the tube 33 retained in the channel 42.
The tube 33 is then moved longitudinally along the channel
while using the blade 91, supported upon the guide surfaces
82, to cut along the tube so as to increase the length of the
base surface 88. When the blade has travelled the required
25 distance to provide the correct length of the base surface for
the notch 34a, the tube 33 is reversed longitudinally in
position within the channel 42 and the blade is cut down into
the tube to the end of the cut 93 for the base surface while
being guided by the guide surfaces 80. The base of the notch
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34a will then be coplanar with a tangent to the top of water
pipe 30 and will fit comfortably against the beam 32.
As a result of the use of the channel 42, all cutting
operations performed on foam insulation tube lengths are
5 performed with each length held in substantially cylindrical
manner. Thus the cut edges are as desired with little or no
resultant tendency for gaps to be formed between abutting
surfaces of adjacent tube lengths after installation.
The first, larger insert channel 44 is for supporting
10 foam insulation tube lengths of smaller diameter than lengths
to be cut in channel 42. As shown by Figures 2 and 21, the
channel 44 has a product support surface profile provided by
opposing side surfaces 92, a base surface 94 and an inclined
surface 96 extending between each side surface and the base
15 surface (see also Figure 5). These surfaces are provided
respectively upon side walls 98, base 100 and inclined side
walls 102. The channel 44 is provided to nest snugly within
the channel 42 with side walls 98 slidably engaging the side
walls 48 as the insert channel 44 is slid down into the
20 nesting position in which the base 100 is supported by the
base surface 52. Upper end surfaces 104 of side walls 98 do
not extend up to the level of guide surfaces 82 but rather to
the junction position 74 of guide surfaces 72. However, the
base 100 may be of suitable thickness to locate the
25 longitudinal axis of foam insulation tube length of the
smaller diameter at the level of the longitudinal axis
position 76 for tube lengths to be cut in the channel 42 as
described above. Hence, a "V" shaped notch cut into the
smaller diameter tube and similar to the notch with sides 24
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(Figure ld) will have the junction position of its sides at
opposite ends of the diameter of the tube length.
Registration means is provided to assemble the channels
42 and 44 together. This registration means comprises a
5 plurality (normally two) of registration pins 106 (Figure 2)
provided in channel 44 for insertion within complementary
bores 108 of the base surface 52. As shown particularly by
Figure 4, bores 108 (and thus the pins 106) are disposed on
the longitudinal centre line 110 of the assembly. However to
10 ensure correct relative angular orientation and longitudinal
positioning of the channels, the bores 108 and pins 106 may
be disposed offset to one side of the centre line 110 as shown
in chain dotted outline for the bores 108. Alternatively, one
of the bores 108 and the corresponding pin 106 from the one
15 end of the channel may be different from the spacing of the
other bore 108 and its pin 106 from the other end.
The channel 44 has a pair of aligned guide surfaces for
a cutting blade. These are provided by guide slots 112 in
side wall 98, and when channels 42 and 44 are assembled the
20 slots 112 are aligned with slots 60 in channel 42 to provide
a 45 degree mitre. The slots 112 are connected by groove 114
in the base surface 94. Similarly, slots 116 interconnected
by groove 118 in the base surface 94 are aligned with the
slots 66 in channel 42 with the channels assembled together
25 for forming a 22.5 degree mitre.
As shown in Figures 20 and 21, with channels 42 and 44
assembled, a foam insulation tube length 120 of smaller
diameter than a tube length 12, is snugly accommodated within
the channel 44 with its lower regions supported by surfaces
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92, 94 and 96 to retain the tube length 120 in cylindrical
condition during cutting. The tube length 120 may then be
provided with either of the mitred cut ends, a " V" shaped
notch, or a rectangular cut out similar to those described in
5 use of the channel 42.
For the cutting operation as shown by Figures 20 and 21,
the axis of the tube length 120 is coincident in position to
that of a tube length 12 when carried by channel 42.
In the event that an even smaller diameter foam
10 insulation tube length (not shown) should require cutting in
the manner described for tube lengths 12 and 120, the second
and smaller insert 46 is used (Figures 2 and 6). This channel
is identical to the channel 42 in design (except that it is
smaller) and has side walls 122, a base 124, and inclined side
15 walls 126 which provide a product support surface profile in
the form of opposing side surfaces 128, base surface 130, and
inclined surfaces 132. Registration means, comprising
registration pins 134 in the base 124, register within
registration bores 136 formed into the base surface 94. The
20 pins 134 and bores 136 are displaced relative to the
corresponding pins 106 and bores 108.
The channel 46 is nestable within the channel 44 with the
base 124 supported upon the base surface 94. Cutting blade
guide slots 138 and 140 in side walls 122 and 126 become
25 aligned, respectively, to the guide slots 112 and 116 in the
channel 44 for cutting purposes. Slots 138 are interconnected
by a groove 142 formed in the base surface 130 while slots 140
are interconnected by groove 144 in the base surface. For
reasons similar to those associated with the channel 44, the
18
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base 124 of channel 46 is sufficiently thick to locate the
longitudinal axis of a tube length to be cut at the level of
the longitudinal axis position 76 for a tube length 12 when
this is accommodated in the channel 42.
As mentioned above, the base 100 may be of suitable
thickness to locate the longitudinal axis of a tube length of
smaller diameter at the level of the axis position 76 for tube
lengths to be cut in the channel 42. However, the smaller
diameter tube length cannot extend up to the correct position
10 for a notch 34 to be cut using the guide surfaces 82 while
locating the base of the notch coplanar with a tangent to the
top of a water pipe to be contained within the tube length.
For certain differences in diameter, the compressibility of
the foam will accommodate the difference between the positions
15 of the base of the notch and this tangent. Hence, if the
channel 42 is used for cutting a 0.75 inch diameter tube
length and the channel 44 is provided for cutting a 0.5 inch
diameter tube length, then the discussed difference is 0.125
inches and is acceptable. However, for the even smaller
20 diameter tube length to be cut in the channel 46, the
difference between the two positions increases and may not be
acceptable. In this situation, for cutting a notch 34, by way
of compromise, the channel 44 is dimensioned to place its
surfaces 104 at the height corresponding to the plane of the
25 tangent of the tube to be fitted within the channel. This
then may allow for an acceptable difference between the two
positions for each of the largest and smallest diameter tube
lengths.
19
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It should be appreciated that the greater the number of
support surfaces, the better will be the support for the tube.
Although the above-described embodiment has five support
surfaces, namely two side surfaces, two inclined surfaces and
5 a base surface, it is envisaged that more or fewer could be
provided, though a minimum of four is believed to be required
for adequate support.
In a second embodiment shown by Figure 22, a cutting jig
lS0 has a channel 152 which provides a support for a first
10 insert channel 154 which, in turn, provides a support for a
smaller insert channel 156. The channels 152, 154 and 156
have some of the same basic features, respectively, as
channels 42, 44 and 46 of the first embodiment and of these
same features, like reference numerals are used in the second
15 embodiment.
The second embodiment differs fundamentally from the
first embodiment, however, in the shapes of the product
support surfaces and the shapes of the channels to support
those surfaces. In the case of the channel 152, a base 158
20 and sidewalls 160 between them define a smoothly contoured
product support surface profile. This is formed by vertical
planar surfaces 162 defined by each sidewall, the surfaces 162
extending tangentially into a semicylindrical base surface
164. The radius of the base surface 164 corresponds to the
25 outside diameter of a foam tube length to be cut. The first
and larger insert channel 154 is semicircular in end view with
another surface 168 complementary to the base surface 164 to
enable the channel 154 to be supported within the channel 152
when cutting a tube length supported within the channel 154.
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The radius of the inner surface 170 corresponds to that for
the tube length to be cut within the channel 154. The second
and smaller insert channel 156 is also semicircular to fit
snugly within the insert channel 154. The channel 156 has an
5 inner surface 172 corresponding in radius to the radius of a
tube length (not shown) to be supported by channel 156 during
cutting. Because of the semicircular profile of the support
surfaces of the three channels, the tube lengths to be cut are
supported around their entire lower peripheries during
10 cutting. This is shown by the position of tube length 174
within the channel 152 during cutting. Hence the jig of the
second embodiment has the same advantages obtained in use of
the jig of the first embodiment while offering better support
for tube lengths during cutting.
In third and fourth embodiments now to be described,
different size but otherwise similar jigs form a kit for use
in cutting tubes of different diameters.
In the third embodiment (Figure 23) three jigs in the
form of channels 176, 178 and 180 are each of exactly the
20 structure of channel 42 and provide a kit of cutting jigs.
The jigs have similar features, as shown by the same reference
numerals as in the first embodiment. These channels 176, 178
and 180 are, of course, each intended to be used separately
from the other channels and indeed its shape prohibits it from
25 being used with the other channels. Each channel is of the
correct inside profile shape to support in substantially
undistorted manner a tube length of specific diameter during
cutting.
CA 02202731 1997-04-1~
In a fourth embodiment (Figure 24), three jigs provide
a kit in the form of channels 182, 184 and 186. Each channel
is basically of the structure of each of jigs 176, 178 and 180
except that the product support surface 188 of each jig of the
5 fourth embodiment has the profile of base and side wall
surfaces 162 and 164 of the channel 152.
Although embodiments of the invention have been described
and illustrated in detail, it is to be clearly understood that
the same are by way of illustration and example only and not
10 to be taken by way of the limitation, the spirit and scope of
the present invention being limited only by the appended
claims.
