Note: Descriptions are shown in the official language in which they were submitted.
OJ~
This invention relates to a clamping device for
regulating fluid flow through flexible tubing and, more
particularly, to a clamping device for use in intravenous
parenteral fluid administration sets.
Many clamps have been developed for controlling
the rate of flow of parenteral fluid administered to a
patient through the plastic tubing which is used for
transporting parenteral fluid from the solution container
to the patient. However, these clamps have not proved as
reliable and accurate in use as desired, particularly with
respect to regulating and maintaining uniform flow rates
over extended periods of time.
Most clamps are designed to flatten tubing so
that the walls of the tubing are more or less parallel
producing a long flat oval-shaped lumen. The rate of flow
of fluid through tubing compressed in this manner is
difficult to control prPcisely, and considerable compression
of the walls of the tubing must be applied before slow
rates of flow can be obtained. Moreover, there is con-
siderable strain imposed on the plastic by clamps of thistype. Und~r such strain, most plastics undergo "sold
flow" to relieve the strain causing the tubing to flatten
still further and collapse inwardly thus decreasing the
fluid flow rates. As a result, the nurse or attendant
must frequently readjust the clamp to maintain relatively
constant fluid flow.
Most tubing used in intravenous sets for adminis-
tering parenteral solutions is made of polyvinyl chloride
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which has the tendency to take a "set" when compressed for
prolonged periods of time. Accordingly, unduly long time
lags frequently occur when prior art clamps are released
after a prolonged compression before the plastic overcomes
the "set". Other plastic tubing, for example, polyethylene
tubing, can be permanently deformed when compressed making
it virtually impossible to reestablish a higher flow rate.
A few clamps have been developed which do not
flatten the tube uniformly as shown, for example, in U.S.
Patent No. 3,685,787. This clamp consists of a base
having a tapered V-shaped groove into which plastic tubing
is progressively compressed by a roller in such a manner
that there is essentially no space for the plastic to
"cold flow" into since the peripheral surfaces of the
tubing are confined. More constant fluid flow rates are
achieved with this clamp, but flow rates still fluctuate
with time. Moreover, the upper surface of th tubing can
bow inwardly and decrease the flow rate. Also, this clamp
suffers the same drawback as other clamps with respect to
being slow in reestablishing a faster flow rate.
Another attempt to solve the problem of control-
ling fluid flow in intrav~nous tubing is described in U.S.
Patent No. 3,802,463. With this device, opposed walls of
the tubing are variably compressed to modify the size of a
pair of lumens formed along the outer edges of the compressed
tubing. Central portions of the opposite walls are brought
together in gradually increasing interior surface contact
so that the lumens in the uncompressed outer edges gradually
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decrease in size until flow of fluid through the tubing ceases.
As with the clamp described in U.S. Patent No. 3,685,787, the
device described in U.S. Patent No. 3,802,463 places non-uniform
stresses on the tubing clamped by the device. Thus, flow rates
show undesirable fluctuations with time.
Another problem encountered with previously known
clamping devices is that the devices are usually designed for a
particular size of tubing. Thus, a change in tubing size re-
quires a change in the dimensions of the clamp being used.
Accordingly, it is an object of the present invention
to overcome the disadvantages of the previously known clamping
devices for regulating fluid flow through flexible tubing.
According to the present invention, then, there is
provided an intravenous tubing clam~ing device for controlling
fl~id flow through compressible tubing comprising: an elongated
body member adapted to receive the tubing having a proximal end
and a distal end; the body member including a generally V-shaped
bottom wall defining two supporting surfaces for the tubing ex-
tending longitudinally of the body member and having a substan-
tially constant width and an apex angle of about 60 to 165;
roller means mounted on the body member or movement longitu-
dinally of the body member and including a roller for defining a
clamping area between the roller means and the supporting sur~
faces which decreases as the roller means moves from the proximai
end of the body member toward the distal end, the clamping area
between the roller means and the supporting surfaces being re-
ducible to an area less than the cross-sectional area of the
unclamped tubing.
In accordance with a preferred embodiment of the pre-
sent invention, an improved clamping device for controlling fluid
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flow, ~lch ~ lltra~enous fluid flow, is provided. The improved
cl~mlpin-! device includes a roller and an elongated body member.
The ~ody member is formed of longitudinally-extending parallel
side walls which are interconnected by a bottom wall. Each of
the side walls, in an upper region, is provided with a longitu~
dinally-extending slot or groove for supporting axially extend-
ing trunnions of the roller. The body member at its proximal
end is enlarged to allow positioning of the roller within the
body member with the trunnions of the roller guided in the slots
or grooves of the side walls. The bottom wall interconnecting
the side walls has a generally V-shape with the distal ends of
the V-shaped bottom wall merging with the bottoms of the side
walls and the apex of th~ V-shaped bottom wall positioned below
the side walls. The apex angle of the V-shaped bottom wall is
between about 60 and 165. r~he outer circumference of the
roller also has a generally ~-shape having its apex positioned
centrally of the roller and its distal ends extending towards
the axis of the roller. The apex angle o~ the roller is selected
based on the angle of the apex of the bottom wall and varies
between about ~0 and 180. ThQ apex angle of the roller may be
10 to 50 more than the apex angle of the bottom wall. The
apex angle of the bottom wall, the apex angle of the roller, and
the position or orientation of the supports for the roller pro-
vided by the side walls of the body member are interrelated in
such manner that longitudinal movement of the roller towards the
distal end of the body member progressively compresses flexible
tubing positioned between the body member and the roller.
In another embodiment of applicant's invention, the
apex angle of the bottom wall is constant while the distance
3~ between the supports for the roller and the bottom wall pro-
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gressively decreases in a direction towards the distal end ofthe body member. Thus~ as the roller moves toward the distal
end, the apex of the circumference of the roller progressively
moves toward the apex of the bottom wall. In this manner, the
lumen or fluid flow passage within the flexible tubing can be
progressively reduced until a desired flow rate is obtained or
until the tubing is sufficiently compresced to prevent fluid
flow.
In yet another embodiment of applicant's invention,
the distance between the supports for the roller and the bottom
wall is constant while the apex angle of the bottom wall is
progressively changed from a value less than the apex angle of
the roller to a value approximately equal to the apex angle of
the roller. This progressive change in apex angle is obtained
by moving the apex of the bottom wall in an upward direction
towards the roller, the width of the V-shaped bottom wall adja-
cent the side walls remaining constant.
In still another embodiment of applicant's invention,
both the distance between the supports for the roller and the
bottom wall and the size of the apex angle of the bottom wall
are progressively changed. Thus, this embodiment of applicant's
invention combines the features of the two previously discussed
embodiments.
When the apex angle of the roller is 60 or slightly
more, the point or apex of the V-shape of the roller is pre-
ferably slightly rounded or curved to facilitate movement of the
roller along the tubing. Preferably, also, the peripheral sur-
face of the roller is slightly knurled or axially slotted or
ridged to facilitate turning of the roller. Further, this pro-
vides a limited degree of frictional resistance between the com-
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pressed tubing and the roller that tends to maintain the rollerin a desired position.
With applicant's invention, the lumen or orifice formed
in the tubing is generally V-shaped. Thus, compressive forces
tend to be more generally distributed across the tubing and not
limited to certain areas, as with the prior art devices. This
more even distribution of compressive forces tends to eliminate
"cold flow" in the compressed tubing and results in essentially
no dimensional changes of the tu~ing. In addition, since the
tubing is clamped in a V-shape, any inward movement of the upper
surface of the tubing is resisted. Thus, use of the device pro-
vides more uniform fluid flow through the tubing over extended
periods of time.
Embodiments of ~he invention will now be described in
greater detail and will be better understood when read in con-
junction with the following drawings in which;
Figure 1 is a perspective view of one embodiment of a
clamping device in accordance with the present invention;
Figure 2 is a cross-sectional view of the embodiment
of Figure 1 taken along plane 2~2 of Figur~ l;
Figure 3 is a cross~sectional view of the embodiment of
Figure 1 taken along plane 3 3 in Figure 2;
Figure 4 is a cross-sectional view of the embodiment of
Figure 1 taken along plane 4-4 in Figure 2;
Figure 5 is a cross~sectional view of the embodiment
of Figure 1 taken along plane 5-5 of Figure 2;
Figure 6 is a view similar to Figure 4 of another em-
bodiment of the clamping device of the present invention;
Figure 7 is a view similar to Figure 4 of still another
embodiment of the clamping device invented by applicant;
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Figure 8 i5 a view similar to Figure 4 of a still fur-
ther embodiment of a clamping device according to the present
invention;
Figure 9 is a view similar to Figure 2 of another em--
bodiment of the clamping device of the present invention;
Figure 10 is a cross~sectional view of the embodiment
of Figure 9 taken along plane 10-10 of Figure 9;
Figure 11 is a cross-sectional view of the embodiment
of Figure 9 ta~en along plane 11~11 of Figure 9; and
Figure 12 is a cross-sectional view of the embodiment
of Figure 9 taken along plane 12-12 of Figure 9.
Because clamping devices are well known, the present
description will be directed in particular to elements forming
part of, or cooperating more directly with, the present invention.
Elements not specifically shown or described herein are under-
stood to be selectable from those known in the art.
Referring now to the drawings, and to Figures 1-5 in
particular, one embodiment of the present invention is illustrat-
ed and will be described in connection with a clamping device,
generally designated 20.
The clamping device 20 has a body member 22 and a
roller 24 operatively associated therewith. The body member 22
and the roller 24 are preferably made of relatively rigid plastic
or similar material. The body member 22 is generally elongated
and has generally parallel side walls 26, 28 integral with a
bottom wall or floor 30. One or more members or struts 31 inter-
connect ends of upper portions of walls 26 and 28.
The side walls 26, 28 have grooves or slots 32 and 34,
respectively, for supporting trunnions 36 which extend axially
from the roller 24. As illustrated in Figure 2, both the proximal
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end 38 of the body member 22 and slots 32, 34 are enlarged to
define an opening 40 which facilitates insertion of roller 24
into the body member. Further, the flared ends of the side
walls 26~ 28 of the embodiment illustrated in Figure 2 are axial-
ly extended to define a space in which roller 24 can rest without
applying pressure to compressible, elongated flexib~e tubing 42
positioned between the roller 24 and body 22. This feature
greatly facilitates movement of clamping device 20 along tubing
42.
As illustrated in Figures 3-5, both a supporting por-
tion of bottom wall 30 and the circumference of roller 24 have
a generally V-shape. As seen in Figure 2, the supporting por-
tion of bottom wall 30 starts in the vicinity of line 3-3.
Also, the roller 24 is positioned in the slots 32, 34 in such
manner that the apex 44 of body member 22 and the apex 50 of the
roller 24 are in general alignment. Thus, the apices form co-
operating clamping members. As the roller 24 moves to the left
in Figure 2, apex 50 tends to progressively pinch tubing 42
thus reducing the size of lumen 56 inside tubing 42- Thus, move-
ment of roller 24 provides selective control of fluld fl~ throuqh
tubing 42. It should be noted that the manner in which apex
50 compresses the walls of tubing 42 forms a ~--shaped lumen 56,
as illustrated in Figure 4, which tends to evenly distribute
the compressive force exerted on tubing 42, thereby reducing the
tendency of "cold flow" in the compressed tubing. Moreover, the
lumen 56 does not have a tendency to change in size or shape
since any movement of the upper or lower wall is balanced by an
equal movement of the other wall. Also, since there is no undue
compression exerted on the tubing 42, the tendency of the tubing
to "set~ is greatly reduced. Further, frictional forces between
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the compressed tubing and the circumference of roller 24 tend
to retain the roller in a desired position.
In operation, tubing 42 is placed inside body member
22 of clamping device 20, and the body member is moved to a
desired position on the tubing. Roller 24 is then inserted into
the opening 40 and trunnions 36 are positioned in slots 32 and
34. The trunnions and slots are so designed that the trunnions
fit in a loose manner within the slots. The gradual slope of the
slots 32, 34 provides the ability to constantly control or vary
fluid flow rates. Also, as previously discussed~ the V-shaped
lumen formed by the progressive collapse of the tubing tends to
maintain its size with essentially no dimensional changes in the
tubing resulting from "cold flow".
It should be noted that, in the embodiment illustrated
in Figures 1~5, the apex angle of the bottom wall 30 is approxi-
mately 90 while the apex angle of the circumference of roller 24
is approximately 105. These apex angles have been found to
yield excellent results. Another embodiment, as illustrated in
Figures 9-12, utilizes a roller having an apex angle of 150 and
a bottom wall having an apex angle of 135 at the proximal end of
the body member. Still other possible apex angle relationships
are illustrated in Figures 6-8. In these figures, reference
numerals will be combined with alphabetical characters to identi-
fy features similar to those previously discussed.
Referring now to Figure 6, wheel or roller 24a has an
apex angle of approximately 60, and bottom wall 3Qa has an
apex angle of approximately 60. With this embodiment, the tip
of the apex 50a of the roller is slightly beveled or rounded to
facilitate movement of the roller. The beveling is provided for
the convenience of a user. Excessive beveling can adversely
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affect the clamping action of the roller. Also, with this em-
bodiment, the circumference of roller 24a has been modified to
add axial grooves to aid gripping of the roller. The grooves
are formed to be shallow and close together.
Turning now to Figure 7, an embodiment is illustrated
in which wheel or roller 24b has an apex angle of approximately
85 and bottom wall 30b has an apex angle of approximately 90.
With this embodiment, the roller 24b has both axial grooves to
aid gripping and serrated edge portions to reduce the possibi-
lity of slippage. Note that apex 50b is not rounded, as illus-
trated in the embodiment of Figure 6.
Figure 8 illustrates an embodiment of applicant's in-
vention in which the circumference of the wheel or roller 24c is
flat, i.e.~ the apex angle is about 180. It will be readily
appreciated that the peripheral surface of the roller is there-
fore parallel to the axis of the roller. This feature is pe-
culiar to this particular embodiment for in other embodiments
described herein no parallel relationship exists between the
axis of rotation of roller 24 and the apex surfaces thereof or
with the supporting portions of bottom wall 30. With this embo-
diment, support or bottom wall 30c has an apex angle of appro-
ximately 165. Also, with this embodiment, side walls of roller
24c are serrated or formed with ridges to reduce the possibility
of slippage between side walls 26c, 28c and sides of roller 24c.
From the preceding description of various embodiments
of applicant's invention~ it can be seen that the apex angle of
the support or bottom wall can vary between about 60 and 165,
preferably between about 90 and 135, and the apex angle of the
wheel or roller can vary between about 60 and 180, preferably
between about lOS and 150. Further, the apex angles of the two
109~r;01~
Illenll)erS C.tl- b~` eitl~el the same or slightly different from each
other. ~refera~ly, the apex angle of the wheel or roller should
be larger than the apex angle of the support or bottom wall.
Normally, it is preferred that the apex angle of the wheel or
roller be 10 to 50 greater than the apex angle of the support,
a difference of approximately 15 providing the best
results.
Turning now to Figures 9-12, an embodiment of appli-
cant's invention is illustrated in which the apex angle of the
support or body wall increases from the proximal to the distal
end of the clamping device. With this embodiment, reference
numerals with primes attached have been used to identify compo-
nents similar to components previously described.
As illustrated in Figures 9-12, clamping device 20'
has a body 22' formed of parallel side walls 26', 28' inter-
connected by a bottom wall or floor 30'. The bottom wall 30'
has a generally V-shape with the distal ends of the V merging
with the bottoms of side walls 26' and 28' and the apex of the
V preferably centered between and located below the bottom of
the side walls. The side walls 26', 28' include slots or grooves
32', 34' for supporting trunnions 36' of roller 24'. As illus-
trated in Figure 9, the slots have an enlarged opening 40' and
extend longitudinally toward the distal end of body 22'. For
most of their length the slots are parallel to the bottom edge
of side walls 26', 28',
With this embodiment, compression of the tubing 42 is
obtained by gradually changing the apex angle of the bottom wall
30'. For instance, as illustrated in Figure 11, the roller 24'
has an apex angle of approximately 150 while the bottom wall
30~ has an apex angle of approximately 135. The apex angle ot
the hottom wall is gradually changed by moving the apex in an
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12
upward direction until the apex angle of the bottom wall reaches
a desired value, such as approximately 150, as illustrated in
Figure 12. The distance separating the side walls 26', 28'
remains unchanged during the upward movement of the apex of
bottom wall 30' towards the roller.
The embodiment illustrated in Figures 9-12 functions
in basically the same manner as the previously described
embodiments. Hence, reference is made to the description of
the operation of the device illustrated in Figures 1-5.
The invention has been described in detail with
particular reference to preferred embodiments thereof, but it
will be understood that variations and modifications can be
effected within the spirit and scope of the invention. For
instance, the embodiment of applicant's invention illustrated
in Figures 1-5 can be combined with the embodiment illustrated
in Figures 9-12 to form a device in which the slots for guiding
the trunnions of the rollers are angles progressively downwardly
in a direction toward the distal end of the body, and the apex
angle of the bottom wall increases in a direction towards the dis-
tal end of the body. In addition, the apex angle of the bottom
wall in the embodiment illustrated in Figures 1-5 can be abrupt-
ly increased at the far distal end of the clamping device to
equal the apex angle of the roller rather than being progressive-
ly increased as in the embodiment illustrated in Figures 9-12.
These and other modifications of the disclosed devices will be
readily apparent to those skilled in the art and are intended to --
be covered by the appended claims.
