Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HOSE CLAMP
FIELD OF THE INVENTION
The present invention concerns clamps, more particularly to clamps for use
with
hoses.
BACKGROUND OF THE INVENTION
Hose clamps are well known and widely used in industry and are practical and
reliable in applications requiring large controllable holding force.
Conventionally, hose clamps include a loop of resilient material such as
stainless steel, steel or plastic, which loops around the outside wall of a
hose
and applies a clamping force thereto. However, there exist applications where
it
is desirable to apply and maintain constant torque forces against the hose
clamp so as to retain high clamping forces during expansion and contraction of
the hose during extremes of temperature and pressure. Such temperature and
pressure fluctuations are typical for hoses used on, for example, automobile
exhaust systems. In addition, mechanical stresses such as vibrations and
dynamic stresses, normally encountered during operation of the automobile
engine, are sufficient to dislodge hose clamps that are not clamped by
sufficiently strong clamping forces.
A number of designs for hose clamps exist, including:
= US Patent No. 4,819,307, issued April 11, 1991 to Turner for "Hose
Clamp";
= US Patent No. 5,010,626, issued April 30, 1991 to Dominguez for "Hose
Clamp with Flanged Captive Tensioning Nut and Pivoted Bridge
Element";
= US Patent No. 5,299,344, issued April 5, 1994 to Oetiker for "Reinforcing
Arrangement for Open Hose Clamps, Especially Screw-Type Hose
Clamps";
= US Patent No. 5,720,086, issued February 24, 1998 to Eliasson et al. for
"Clamping Collar"; and
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= WO 01/27516A1, published April 19, 2001 to Dominguez for "Improved
Clamp with a Tightening Screw".
These hose clamps, however, suffer from a number of important disadvantages.
Most clamps use a bolt that applies a clamping force directly against a
shoulder
of a loop end. During application of high torque forces during the clamping
operation, the force direction may not be axially applied in a constant manner
due to deformation of the shoulder by the clamping forces. This non-constant
application of torque force across the loop end may be prone to failure during
temperature related expansion and contraction of the hose.
Disadvantageously, most hose clamp designs use T-bolts and coil springs
made of steel, which is prone to corrosion and freezing under normal hot/cold
and humid operation conditions, thus decreasing the clamping torque of the
clamp over time and severely limiting the life cycle thereof. In addition,
most
coil springs limit the amount of force that can be applied during clamping,
especially when corrosion resistant spring material is used such as stainless
steel. For example, the maximum applicable torque load over an existing
enlarge coil spring clamp of a specific hose diameter, such as the clamp part
No. BRZ-B9226-0406 from Breeze Industrial Products CorporationTM, is about
100 in-lbs (at full compression of the coil spring) to hold a maximum internal
hose pressure of about 55-60 psi (pound per square inch) and 160 in-lbs at
failure (physical breakage of the clamp); as depicted by curve 90 of Figure
12.
In order to sustain much higher hose internal pressure up to and above 100 psi
by increasing this maximum workable torque load up to and above 150 in-Ibs, or
the maximal load rating of the clamp, the coil spring would need to be of an
outer diameter of about three times (3x) than that of an equivalent loading
capacity disc spring, such as about at least two inches (2 in), which could be
as
large as the hose itself and would therefore prove unpractical and unusable.
Other types of clamps use disc springs made of stainless steel or tungsten
alloys to improve the load constancy over temperature induced deflection,
irrespective of any maximal load and corrosion considerations. Other types of
hose clamps use worm gears to apply torque forces to the clamp, which worm
gears may be unsuitable in operations requiring constant high clamping torque.
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In some cases, to avoid damage or rupture of the clamp during operation, it
would be advisable to have a better control the constancy of the clamping
torque over operational conditions of the clamp.
Thus there is a need for an improved heavy-duty hose clamp that can be used
to apply and maintain substantially constant high clamping forces over
operational life conditions thereof.
SUMMARY OF THE INVENTION
The present invention is directed towards a solution to the aforesaid problems
by providing a heavy-duty hose clamp with a novel spacer that allows a user to
axially apply constant significant torque forces during a clamping operation,
especially because of the curved portions of the bolt head and nut freely
pivotally engaging respective looped ends of the loop or band. A novel
combination of the spacer, capture nuts and an arrangement of a number of
axially aligned disc springs maintain constant high clamping forces around the
hose. The capture nuts are shaped to allow inward transfer of the clamping
forces from a bolt to looped ends to close the gap therebetween and to reduce
the clamp loop around the hose. Advantageously, the clamp significantly
increases the magnitude of working clamping torque that is safely available to
the user, easily up to about 420 in-Ibs, and the adjustment thereof, depending
on the disc arrangement as well as the geometrical configuration of the disc.
The hose clamp of the present invention, especially because of the use of disc
springs, is simple to operate and is manufactured from inexpensive,
lightweight
and readily available corrosion resistant materials, such as stainless steel
or the
like. The hose clamp can be custom made to fit many hose dimensions, up to
about 35 inches in diameter, and uses readily available tools to apply the
clamping forces to the bolt. In addition, the user can select many
combinations
of the disc springs' orientation and quantity to apply a variety of different
clamping deflections for the clamping operation required. Also, varying the
quantity of disc springs allow to control of the amount of displacement
between
the two looped ends for a substantially constant clamping torque over the
amount of hose circumferential variation (contraction/expansion). Varying the
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physical characteristics of the disc springs such as the disc thickness allows
determining the maximum clamping torque capability of the hose clamp.
In a first aspect of the present invention, there is provided a heavy-duty
clamp
for a hose, the clamp including a loop for disposing around the hose and
having
first and second axially spaced apart looped ends, the clamp comprises: a
force
generator, for drawing together the first and second looped ends, and
connected to the first and second looped ends to apply a predetermined axial
clamping force to the loop within a maximal axial clamping force rating of
said
clamp, the force generator including a bolt and a plurality of disc springs
mounted thereon and made out of steel alloy material so as to allow said
predetermined axial clamping force to be substantially high and constant under
circumferential expansion and contraction of the hose over temperature
operational condition thereof; a spacer member mounted on the force generator
between the plurality of disc springs and the first looped end and axially
transferring the clamping force from the force generator to the first and
second
looped ends, the clamping force axially drawing together the first and second
looped ends so as to clamp the hose; and means for adjusting said maximal
axial clamping force rating, said adjusting means including said plurality of
disc
springs being stacked against one another into one of a plurality of disc
arrangements.
In one embodiment, the one of a plurality of disc arrangements includes said
plurality of disc springs being arranged in series.
In another embodiment, the one of a plurality of disc arrangements includes
said plurality of disc springs being arranged in parallel.
In a further embodiment, the one of a plurality of disc arrangements includes
said plurality of disc springs being arranged in pairs of parallel disc
springs, said
pairs being arranged in series.
In one embodiment, each said disc spring has a conical shape configuration
defined by a disc thickness and a disc conical angle, said adjusting means
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further including said plurality of disc spring being selectable from one of a
plurality of disc configurations.
In one embodiment, the first looped end includes a first outer face and a
first
5 inner face, and the second looped end includes a second outer face and a
second inner face, the first and second outer faces being angled inwardly
towards each other and the first and second inner faces being curved and
disposed inwardly towards each other. The first looped end includes first and
second holes located in the respective first outer and inner faces and the
second looped end includes third and fourth holes located in the respective
second outer and inner faces, the holes being axially aligned with each other.
Typically, the bolt has a first bolt end and a second bolt end, and passes
through the first, second, third and fourth holes. The bolt includes a
threaded
portion and a non-threaded portion, the non-threaded portion extending through
and away from the first looped end. The plurality of disc springs and the
spacer
member are slidably mounted on the non-threaded portion, the plurality of disc
springs being located near the first bolt end.
Typically, the force generator further includes a first capture nut mounted in
the
first looped end and a second capture nut mounted in the second looped end.
The first capture nut includes a non-threaded axial bore. The second capture
nut includes a threaded axial bore. The first and second capture nuts each
includes a curved end and a stem portion.
Typically, the spacer member includes a cylindrical collar with an axial bore
sized to accommodate the bolt therein, the cylindrical collar having a force
receiver end and a force transfer end.
Typically, the stem portion of the first capture nut is disposed towards the
first
hole of the first looped end and abuts the force transfer end.
Typically, the second looped end includes one hole that is axially aligned
with
the first and second holes of the first looped end.
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In one embodiment, the force generator is a T-bolt that passes though the
first
and second holes of the first looped end and through the one hole of the
second
looped end, the T-bolt having a T-bolt end and a threaded bolt portion on
which
is movably mounted a nut, the T-bolt end being located in the second looped
end. The nut includes a smooth outer surface on which are mounted the disc
springs and a threaded bore through which the T-bolt passes.
Typically, the second bolt end includes a nut stop. The nut stop is integral
with
the stem portion of the second capture nut.
Typically, the first hole of the first looped end is larger than the second
hole of
the first looped end.
Typically, the clamp loop, when viewed in cross section, includes a planar
portion and two ends that are angled away from the surface of the hose.
Typically, a plate is hingeably connected to the first looped end is adapted
to be
in a circumferentially aligned relationship with the loop between the first
and
second loop ends when the clamp is disposed around the hose, thereby
substantially clamping a section of the hose located between the first and
second looped ends and bridging a gap therebetween.
Typically, the plate includes a guide portion for guiding the moveable first
and
second looped ends when moving towards and away from each other during
clamping and under circumferential variation of the hose during operation
thereof.
Typically, the plurality of disc springs are made out of corrosion resistant
material.
Typically, the maximal axial clamping force rating of said clamp is within the
range of about 100 in-lbs and about 420 in-Ibs, preferably within the range of
about 150 in-lbs and about 220 in-lbs.
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Other objects and advantages of the present invention will become apparent
from a careful reading of the detailed description provided herein, with
appropriate reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Further aspects and advantages of the present invention will become better
understood with reference to the description in association with the following
Figures, wherein:
Figure 1 is a perspective view of an embodiment of a heavy-duty hose clamp of
the present invention;
Figure 1a is a cross section view taken along line la-la of Figure 1;
Figure 2 is a side view of the hose clamp of Figure 1;
Figure 3a is a partial cutaway view of 10 series pairs of disc springs
arranged in
series and cooperating with a bolt of Figure 1;
Figure 3b is a perspective view of a spacer member;
Figure 4a is a perspective view of a looped end;
Figure 4b is a side view of a looped end with a capture nut located therein;
Figure 5a is a side view of one capture nut;
Figure 5b is an end view taken along line 5b of Figure 5a;
Figure 5c is a side view of a unitary capture nut/Stover nut;
Figure 5d is a side view of a unitary capture nut/Nylon insert;
Figure 6a is a side view of another capture nut;
Figure 6b is an end view taken along line 6b of Figure 6a;
Figures 7a to 7f are simplified section views of a number of disc springs
illustrating different arrangements thereof;
Figure 8 is a top view of a hingeable plate;
Figure 9 is a side view of a second embodiment of the hose clamp;
Figure 9a is a perspective view of a T-bolt engaged a looped end;
Figure 9b is a side view of Figure 9a;
Figure 9c is a partial cutaway side view of a nut of Figure 9;
Figure 10 is a side view of a third embodiment of the hose clamp;
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Figure 11 is a side view of a fourth embodiment of the hose clamp;
Figure 12 is a graphical representation of the internal hose pressure
sustainable by a heavy duty clamp of the present invention and by a
conventional coil spring clamp in function of the clamping torque applied
thereon; and
Figure 13 is a graphical representation of the spring deflection allowed by a
heavy duty clamp of the present invention with different disc spring
arrangements and by a conventional coil spring clamp in function of the
clamping torque applied thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of a hose clamp 10 of the present invention is shown in
Figure 1. Broadly speaking, the clamp 10 includes a clamp loop 12, two
moveable looped ends 14 and 16, a force generator 18, a separator or spacer
member 20, at least one and preferably a plurality of pairs of disc springs
22,
and a hingeable plate 24; all typically made out of steel alloy material and
preferably a corrosion resistant material such as stainless steel or the like.
Referring now to Figures 1 and 2, in a typical application, an item for
clamping,
for example a high-pressure, heavy-duty hose 26 is received in the clamp loop
12. The clamp loop 12 is disposable axially along a main axis 28 of the hose
26
and annularly around the hose 26. The clamp loop 12 is typically made of
stainless steel, which has sufficient resilience to withstand high operating
torque
forces applied thereto. The clamp loop 12 includes the two moveable looped
ends 14 and 16, one of which will now be described in detail with reference to
Figures 1 and 2. The looped end 14 has an inner face 29 and an outer face 30.
The inner face 29 is continuous with an inner periphery surface 32 of the
clamp
loop 12. The outer face 30 is continuous with an outer periphery surface 34 of
the clamp loop 12 and is angled inwardly. Typically, the clamp loop 12 is
machined from a single piece of material, the ends of which are looped back on
themselves and connected to the outer periphery surface 34 by a securing
means 35 known to those skilled in the art. An example of such securing
means include stamping, welding or staples and the like. In a default, non-
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clamping configuration, the inner faces 29 are axially spaced apart from each
other and define a gap therebetween. The clamp loop 12 materials are
sufficiently resilient to allow the moveable looped ends 14 and 16 to move
towards each other, when subjected to clamping forces. In a clamping
configuration, the hose 26 is clamped between the inner periphery surface 32
of
the clamp loop 12 by the force generator 18 acting against the moveable looped
ends 14 and 16.
As best illustrated in Figure 1 a, the clamp loop 12, in a clamping
configuration
when viewed in cross section, includes two ends 13 that are curved away from
the hose 26 surface and a generally planar portion 15 which rests against the
surface of the hose 26. The two curved ends 13 prevent the clamp loop 12 from
biting into the hose 26 during clamping and reduce damage to the surface of
the
hose 26.
Referring now to Figures 4a and 4b, each of the looped ends 14 and 16 has two
openings or holes 36 and 38 disposed therein. The holes 36 and 38 are axially
aligned with each other and with the holes of the other moveable looped end.
The holes 36 and 38 have an axis 40, which are aligned generally
perpendicularly to the main axis 28 of the hose 26 during clamping. The hole
36 is disposed outwardly, whereas the hole 38 is disposed inwardly towards the
gap. The hole 36 is generally of a larger size than hole 38 and is elliptical
to
allow the user to move the force generator 18 up and down to allow the force
generator to be aligned with the hole 38. In addition, each of the looped ends
14 and 16 include a second opening 42, which has a second opening axis 44
that is generally perpendicular to the axis 40 and which is generally parallel
to
the main axis of the hose 26. The moveable looped ends 14 and 16 each have
an inner surface 46 that defines the second opening 42. The inner surface 46
has a curved portion 48 and a generally planar portion 50. The curved portion
48 is disposed inwardly towards the other looped end and the gap there
between.
Referring to Figures 2 and 3a, the force generator 18 passes through the holes
36 and 38 and cooperates with one of the outer faces 30 to apply an inwardly
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directed force thereto to draw the moveable looped ends 14 and 16 towards
each other. In this embodiment, the force generator 18 is a bolt 52 that is
sized
to pass through each of the holes 36 and 38. The bolt 52 typically includes
threads along a threaded portion 53 and a non-threaded smooth portion 55 on
5 which the disc springs 22, that form a means for adjusting a displacement of
the
two looped ends 14, 16 relative to one another under the predetermined
clamping force and under circumferential variation of the hose 26 over its
operational condition range, are slidably mounted to allow for their smooth
compression and expansion. The bolt 52 also includes a first bolt end 74 and a
10 second bolt end 54.
Referring to Figures 2, 5a, 5b, 6a and 6b, the force generator 18 also
includes
two capture nuts 56 and 58 are positioned in the second openings 42. Both
capture nuts 56 and 58 cooperate with the inner surface of the looped ends 14,
16 to generate the inwardly directed forces thereon. The capture nut 56 has a
non-threaded axial bore 57, whereas the capture nut 58 has a threaded axial
bore 59, both bores 57 and 59 are sized to allow engagement with the bolt 52.
The bolt 52, in the clamping configuration extends through each of the bores
57
and 59, the end 54 of the threaded bolt extends outwardly from capture nut 58.
Both capture nuts 56 and 58 include a curved end portion 60 and a stem portion
62. The curved end portion 60 cooperates with the curved portion 48 of the
looped end 14, 16 and is disposed towards the gap. The stem portion 62 is
disposed towards the planar portion 50 of the looped ends 14, 16. The stem 62
of the capture nut 56, located in the looped end 14, is cooperable with the
spacer 20 to receive the inwardly directed force thereagainst. Both capture
nuts
56 and 58 have elongate sides 61 and a shorter side 63. Recesses 65 extends
inwardly from the shorter side 63 of the capture nut 56 to allow access room
to
the pins 76 of the hingeable plate 24 for the pivoting thereof, as further
explained hereinbelow.
As shown in Figures 5c and 5d, a friction nut stop 62a in the form of a Stover
nut or a nylon insert nut, respectively, or an abutting nut stop as a lock nut
(not
shown) may be added to the bolt end 54 after torquing to damp against major
vibrations, and rests against the stem 62 of the capture nut 58.
Alternatively,
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the capture nut 58 and the nut stop 62a may be a unitary piece 58a, in which
the nut stop 62a, Stover nut and nylon insert nut, are integral with the stem
62.
Referring to Figures 2, 3a, and 3b, the spacer member 20 of the present
invention is axially aligned with the holes 36 and 38 in the looped ends 14,
16.
The spacer member 20 is orientated towards the outer face of the looped end
14 to axially transfer the inwardly directed force from the bolt 52 to move
the
moveable looped ends 14, 16 together. The spacer member 20 is a cylindrical
collar 64 with an axial bore 66 of sufficient size to slide over a non-
threaded
portion of the threaded bolt 52. The cylinder 64 has a force receiver end 67
and
a force transfer end 68. The force receiver end 67 abuts a first generally
convex outer face 70 of one of the disc springs 22. The force transfer end 68
abuts the stem portion 62 of the capture 56. Both the ends 67 and 68 have
planar surfaces for contacting the stem 62 and the first face 70 of the disc
spring 22.
Each disc spring 22 essentially has a conical shape configuration defined by a
disc thickness T and a disc conical angle A, as shown in a rest state in
Figure 7a, which determines the required maximal axial compressive force to
fully compress the spring 22 in a flattened and fully deflected state (not
shown).
When stacked against one another into a disc arrangement, a plurality of disc
springs 22 require an overall maximal axial compressive force to fully deflect
the
disc arrangement and providing a corresponding overall deflection, depending
on the disc arrangement. Accordingly, the clamp 10 of the present invention
includes a means for adjusting the maximal axial clamping force rating thereof
by the selection of one from a plurality of possible disc arrangements. The
selection of the disc shape configuration of the disc springs 22 forming the
disc
arrangement is also part of the adjusting means. For a same conical angle A
and disc inner and outer diameters, the larger the disc thickness T is the
larger
the required maximal axial compressive force rating is.
Now referring to Figures 7a to 7f, there are shown different disc
arrangements.
In Figure 7a, the disc spring 22 has a predetermined maximal deflection when
subjected to its maximal axial compressive force. The series disc arrangements
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of Figures 7c and 7e of two and four disc springs 22 require the same maximal
axial compressive force to fully compress or flatten the disc arrangements,
while
the maximal deflections of the arrangements would substantially be two and
four times the maximal deflection of the single disc spring 22 of Figure 7a,
respectively.
Similarly, the series disc arrangements of Figures 7b, 7d and 7f of two, four
and
eight disc springs in pairs of parallel disc springs (two-by-two in parallel)
require
about twice the maximal axial compressive force of the single disc spring 22
to
fully compress or flatten the disc arrangements (because of the pairs of
parallel
disc springs), while the maximal deflections of the arrangements would
substantially be one, two and four times the maximal deflection of the single
disc spring 22 of Figure 7a, respectively.
Referring to Figures 3a and 7a to 7f, one can understand that with the disc
springs 22 axially aligned and stacked against one another with the spacer
member 20 and the bolt 52 to transfer the inwardly directed clamping force to
the moveable looped ends 14, 16, many possible maximal clamping loads can
be achieve depending on the disc configuration and disc arrangement thereof.
In the embodiment shown in Figures 1, 2 and 3a, a number of the disc springs
22 are arranged in a series arrangement in pairs along the non-threaded
portion
of the bolt 52. When a selected number of N (20 disc springs shown in
Figures 1, 2 and 3a) disc springs 22 are arranged in series, the maximal axial
clamping torque force required to flatten (to render flat) all disc springs is
the
same as the one required to flatten a single disc spring, with an overall
compressive deflection being approximately N times the one obtained with a
single disc spring 22. Each pair of the disc springs 22 includes the first
face 70,
an opposite second face 72 and a central space 73 defined by generally
concave inner faces 75. The second face 72 cooperates with the bolt end head
74 to receive the clamping force thereagainst. When fully deflected, the
central
space 73 becomes substantially inexistent or null since the opposed second
faces 72 touch one another.
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From the above, the disc springs 22 can be used in many different
arrangements (as shown in Figures 7a to 7f) and have sufficient resilience to
contract against each other when forces are applied to one or both faces 70
and
72. One skilled in the art will recognize that one disc spring 22 may be used
with the bolt 52 such that either of the first or second faces 70, 72 and the
inner
face 75 receives the clamping force from the bolt end head 74.
As shown in Figure 12, there is shown in curve 92 (same arrangement as for
curve C8 of Figure 13), for a typical heavy-duty clamp of the present
invention
similar to the one shown in Figures 1 and 2 but with eight (8) pairs of single
disc
springs 22, the hose internal pressure that is safely sustainable by the clamp
as
a function of the clamping torque force applied thereto to secure the hose 26.
For example, with a securing applied clamping torque force of about 200 in-
Ibs,
the clamp will sustain a hose internal pressure up to about 200 psi. The
beginning of the flat portion of the curve provide the maximal clamping torque
rating F at which the disc arrangement is fully deflected, while the end
thereof
shows the ultimate clamping torque force U at which the clamp breaks apart or
fails. Curve 90 explicitly shows the same torque limitations F', U' of a
conventional coil spring clamp, which are well bellow the ones of the present
clamp 10. In fact, it would not be practically feasible to obtain the same
clamping torque range as for the disc spring clamp 10 of the present invention
with the conventional coil spring clamp unless the coil spring increases to a
few
inches in diameter.
Typically, as illustrated by an actual tested example of Figure 12,
conventional
hose clamps have an ultimate clamping torque rating U' (at clamp failure) of
about 150 in-lbs torque working force with a workable maximal clamping torque
rating F' (at full deflection or compression of coil spring) of about 100 in-
lbs (as
illustrated with curve 90 of Figure 12), whereas with the hose clamp 10 of the
present invention, this ultimate clamping torque rating U increases
significantly
up to about 420 in-lbs with a workable maximal clamping torque rating F of
about 220 in-lbs (as illustrated with curve 92 of Figure 12). At clamping
torque
values of less than 100 in-Ibs, the clamp of the present invention (curve 92)
is
slightly less efficient than the conventional coil spring clamp simply because
of
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the wider loop 12 providing less pressure by square inch at the loop-hose
contact interface; the wider loop being required to enable the higher
efficient
clamping torque range of the heavy-duty clamp 10.
When clamping a hose 26 with the clamp 10 of the present invention, one can
select the predetermined clamping force to use based on the requirements and
the operational condition of the hose and the clamp, namely temperature and
humidity operational ranges over time. Accordingly, for a same clamping force
or torque, the more bolt linear displacement variation (spring deflection) and
therefore circumferential variation of the hose will be allowed under
operational
condition when more disc springs are used, as seen from curves C6, C8 and
C10 of Figure 13 representing 6, 8 and 10 single (or series) pairs of disc
springs
in series, respectively (C8 being 4 times the arrangement shown in Figure 7e,
C10 being the arrangement shown in Figure 2). Hence, by varying the quantity
of disc springs, the linear displacement of the two looped ends 14, 16 during
the
hose circumferential variation can be adjusted, and the slightly varying
clamping
force controlled. Curve D5 represents a clamp 10 with a disc arrangement of
five (5) pairs of double disc springs 22 in series (5 times the arrangement
shown
in Figure 7d). Although this latter arrangement includes the same quantity of
disc springs as the C10 curve, its clamping torque rating F" is about twice
that
(F) of C10 (because of double or parallel disc springs), 420 in-lbs viz 220 in-
Ibs,
with half the overall maximal deflection (because of five (5) pairs instead of
ten
(10) for C10).
In the case in which the disc arrangement would include a mix of single disc
pairs and double disc pairs in series, its behavior of would provide a larger
deflection rate (more deflection per unit change of clamping torque) at the
low
torque end of the curve than the same end of the corresponding curve
representing an arrangement with only double disc pairs in series, while the
end
of both curves would have an essentially similar deflection rate relative to
one
another since all the single disc pairs would have already been fully
deflected in
that portion of the curve.
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More specifically, when the hose 26, after clamping with a predetermined
clamping force P (which could be anywhere along the torque axis of Figure 13),
expands outwardly such as during operations when the hose 26 carries high
temperature, high pressure fluids such as water, steam, or oil, the outward
5 expansion forces act against the inner periphery surface 32 of the clamp
loop
12 and act against the inwardly directed clamping force P to maintain a
substantially constant clamping force. The hose expansion will make the
clamping torque to slightly increase, as illustrated when moving toward the
right
hand side on any curve C6, C8 or C10 from the force P of Figure 13. The disc
10 springs 20 have sufficient resilience to deform during the expansion such
that
the size of the central space 73 decreases thereby taking up the increase in
the
inwardly directed force of the force generator 18 to compensate for the
expansion of the hose 26 and the increasing distance between the two looped
ends 14, 16.
Similarly, as the hose 26 cools, it will contract and the central space 73 of
the
disc springs 22 will increase in size to compensate for the decreasing
distance
between the two looped ends 14, 16, the disc springs 22 attaining their dish-
like
appearance and the force generator 18 will retain its substantially constant
predetermined clamping force P against the disc springs 22 and against the
hose 26; as illustrated when moving toward the left hand side on any curve C6,
C8 or C10 from the force P of Figure 13. Curve 94 of Figure 13 shows the
spring deflection of a conventional coil spring clamp at its relatively low
clamping torques.
Referring to Figures 1, 2 and 8, the hingeable plate 24 is hingeably connected
to one of the looped ends 14. The plate 24 is continuous, or circumferentially
aligned, with the inner clamp loop periphery 32 and includes two inward
projections 76. The plate 24 may also include a single bar in place of the two
projections 76, which may be positioned across the plate to lock the plate 24
in
place during clamping. The hingeable plate 24 acts as a bridge across the gap
and includes a guide portion 78 located on an outer face 80 for guiding the
moveable looped ends 14 and 16 along a path of travel towards and away from
each other during clamping. The guide portion 78 includes two opposing edge
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walls 82 axially aligned with the openings 36 and 38. The plate 24 allows the
user a means by which the looped ends 14 and 16 can be aligned and allows
maneuverability of the clamp 10 along the hose 26 before clamping. The plate
24 may optionally be swung out of alignment (as shown in outline in Figure 2)
with the looped ends 14 and 16 should the user need to completely disengage
the hose clamp 10 from the hose 26.
Operation
Referring to Figures 1 and 2, generally, the hose clamp 10 is supplied in a
default configuration with the bolt 52 disconnected from the looped ends 16
and
18 and the capture nuts 56 and 58. Considering the initial torque P that is
required and the torque variation that is acceptable for an expected amount of
circumferential variation (contraction/expansion) of the hose over its
operational
condition over time, the user selects the appropriate number of disc springs
22
and adds them to the shaft of the bolt 52 and slides the spacer member 20 onto
the bolt 52 shaft. The bolt 52 is positioned adjacent the non-threaded bore 57
of the capture nut 56 and with the hose 26 to be clamped in place snuggly
against the inner periphery 32, the operator aligns the bolt end 54 with the
hole
38 and the threaded bore 59 of the capture nut 58. The user then applies a
turning force to the bolt end 74 causing the moveable ends 14 and 16 to slide
along the plate 24 towards each other thereby tightening the clamp 10 around
the hose 26 to the required torque. Alternatively, the clamp 10, with the disc
springs 22, the spacer member 20 and capture nuts 56 and 58 aligned, is
slipped over the hose 26, which is connected to a fluid source (not shown).
The
clamp 10 is then tightened as described.
Alternatives
The first embodiment of the hose clamp 10 is useful in many clamping
operations. There may be applications, such as for hoses in areas of limited
accessibility that require the use of a T-bolt in combination with the disc
springs,
the spacer member and a hingeable plate which has limited movement. A
second embodiment 100, illustrated in Figure 9, operates in essentially the
same way as the first embodiment 10 and includes a clamp loop 102, a force
generator 104, a spacer member 106, a capture nut 107, disc springs 108, and
CA 02581562 2007-03-14
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two moveable looped ends 110 and 112. The differences between 10 and 100
will now be described with reference to Figures 9a, 9b and 9c.
The looped end 112 includes a hole 114, an opening 116, a generally planar
outward face 118 and a curved inward face 120. A shaped inner surface 122
defines the second opening 116, a planar portion 124 of which lies adjacent a
T-bolt end 126. During clamping, the T-bolt end 126 pushes against a curved
surface 128 of the second opening 116 and inwardly transfers the clamping
force as the force generator 104 acts inwardly against the looped end 110, as
described for the clamp 10. The force generator 104 includes an elongated
threaded bolt portion 130 and a nut 132 mounted on the bolt threads.
As best illustrated in Figure 9c, the nut 132 has a smooth outer surface 134,
on
which the disc springs 108 (only two are shown) are mounted for sliding and
abutment against the spacer member 106, and a threaded bore (not shown)
through which the bolt 130 passes during clamping. UnEike with the clamp 10,
turning the bolt 130 causes the disc springs 108 to move along the smooth
surface 134 of the nut 132 towards the spacer member 106, while the nut 132
moves down the bolt 130 shaft. The nut 132 may alternatively include a nut
head 133 that is separate from a smooth surfaced sleeve 135 and still work the
same way as the unitary nut 132.
A third embodiment of a hose clamp 200 is illustrated in Figure 10 and
operates
in the same way as the first embodiment of the hose clamp 10. There may be
clamping applications that require the use of a hose clamp loop that has two
gaps between two sets of movable looped ends. The hose clamp 200 includes
first and second clamp portions 202 and 204, which together form a clamp loop
206. Two sets of moveable looped ends 208 and 210 are moveable by two
force generators 212 with two spacer members 214.
A fourth embodiment of a hose clamp 300 is illustrated in Figure 11 and is
structurally similar to the second embodiment 200. The hose clamp 300
includes first and second clamping portions 302 and 304, which together form a
clamp loop 306. Two T-bolts 308 are used together with two sets of moveable
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looped ends 310 and 312, which are moveable by two force generators 314 with
two spacer members 316.
While a specific embodiment has been described, those skilled in the art will
recognize many alterations that could be made within the spirit of the
invention,
which is defined solely according to the following claims.
