Tubing clamb to control flow through compressible tubing

A tubing clamp controlling flow within compressible tubing passing through the clamp which is adapted for inserting the tubing sidewise into the clamp upon opening of a hinged side wall. An adjustable flow controller overlies the tubing and is adapted to rotate, bear upon and squeeze the tubing for precise flow control. A lever arm to actuate the flow controller is in ratcheting engagement with an arcuate bar to hold the lever arm and cylindrical surface of the flow controller in the desired rotative position. The selected position of the lever arm can then be recorded. The tubing clamp can be constructed as a one-piece structure by use of a single mold and prepared as a kit to facilitate use for medical purposes. The assembly of the clamp is thus simplified and the method for controlling flow is accomplished by a series of simple steps.

TECHNICAL FIELD 
This invention pertains to a medical clamp of the type commonly used to 
control flow through tubing when transfusing blood or other medical 
fluids, during dialysis or clinical monitoring procedures. 
BACKGROUND OF THE INVENTION 
Medical clamps for constricting and thereby regulating flow through tubing 
are generally small and light-weight, so that the clamps can be supported 
by the tubing itself. In the medical field, such clamps are commonly used 
as part of a flow control tubing system of regulating medical fluids 
passing through the system. Systems of this type, as well as other medical 
laboratory systems, frequently use compressible plastic tubing with flow 
control clamps to control flow through the tubing. 
Such tubing clamps are set to constrict the tubing for a prescribed flow 
through the tubing, for example, drops per minute or ml/hr. A common 
medical application would be the infusion of medical fluid into a 
patient's venous system. 
When in use, the clamps are frequently removed, relocated and reinstalled 
on the tubing system when the patient is moved or the system is taken down 
and set up again for purposes of changing medications, dosages or 
cleaning. 
One of the major problems associated with previous clamps employed for 
similar purposes is the requirement of threading the plastic tubing 
through the clamp or assembly, like threading a needle, which in most 
cases is typically done by the manufacturer and not the end user. 
The prior art clamps which can be opened for sidewise installation of 
tubing usually have more than one component. This sometimes resulted in 
the loss or misplacing of one of the separable components prior to 
assembly with delay in the installation until the missing component is 
found. 
Also, former tubing clamps may lack sufficient variability or precision in 
regulating flow. For instance, former versions occasionally lack the 
required degree of precision in flow control between certain settings; 
and, medical personnel using the former clamps may have encountered 
difficulty in setting the clamp to the prescribed flow rate. 
In addition to the foregoing disadvantages, some prior flow control devices 
were not provided with any visual means to indicate the adjusted setting 
of the device at the prescribed flow rate. Thus when such flow control 
devices of the prior art were disconnected from the tubing system, for 
example, when taken down for adjusting or putting a new bag or bottle in 
the system, it would then be necessary to manually reset the device to 
provide a similar drip rate. Such resetting is time consuming, leads to 
inaccuracy and represents a negative factor in the prior flow control 
devices. 
Finally, the former flow control devices, which had more than one component 
and were manufactured from plastic molds, required a separate mold for 
each component of the device; and the components of the clamp were 
separate pieces when manufactured. This increases manufacturing costs and 
ultimately the purchase price for the item. An important advantage of 
manufacturing the clamp in a single mold as a one-piece structure is that 
all the required pieces of the clamp are together at the time of use. In a 
medical setting, this factor is important for it decreases the possibility 
that one component of the clamp might be lost or unavailable, thereby 
rendering the device useless. 
SUMMARY OF THE INVENTION 
Accordingly, a principal object of the invention is to provide a tubing 
clamp having a body adapted for sidewise insertion of small gage elastic 
tubing with a rotatable flow controller for constricting the tubing in the 
body to a prescribed flow rate. 
Another object of the invention is to provide a tubing clamp with a 
hingeably affixed second side wall capable of being opened to allow quick 
and easy sidewise insertion of the tubing into the clamp and then closed 
and locked in position around the tubing. 
Still another object of the invention is to provide a tubing clamp with a 
rotatable flow controller having cylinder portion with a cylindrical 
surface at the first end and a lever arm radiating a distance away from 
the cylinder portion at the second end. In addition to the foregoing, the 
invention has as an objective greater precision in flow control by means 
of gradual adjustment of a lever arm, so that a relatively large movement 
of the lever arm results in only a minor rotation of the cylinder portion. 
And rotation of the flow controller, with its cylindrical surface 
contacting the tubing, directly affects the flow rate. 
A further objective of the invention is to provide longitudinal slots 
grooved in each of the side walls of the body member to receive journal 
ends projecting axially from the sides of the cylinder portion of the flow 
controller to facilitate insertion of the tubing and flow controller in 
the body. 
A still further objective of the invention is to provide a tubing clamp 
having, in its most general embodiment, a plane passing through the 
longitudinal slots and the plane of the slots, if extended, intersecting 
the plane of the bottom wall, if extended. 
Another object, in a first modification of the invention, is to provide a 
tubing clamp wherein the bottom wall is elevated from the posterior end 
toward the anterior end of the body to allow gradual tightening of the 
flow controller as it bears upon the compressible tubing lying on the 
bottom wall. 
The invention has the further object of maintaining the prescribed flow 
controlling position after it has been attained by providing anterior and 
posterior braces projecting from either end of the first side wall, the 
braces connected at their outer ends by an arcuate bar coaxial with a line 
passing transversely through the center of each of the longitudinal axes 
of each of the slots, whereby the lever arm extending to, but not 
contacting the arcuate bar, is maintained in selected position by 
frictional contact with the tubing. 
Another objective, in a second modification of the invention, is to provide 
a lever arm having sufficient length to extend over the arcuate bar and to 
include on the arcuate bar a series of ratchet teeth along its entire 
length and a detent on the lever arm. The detent projects from the outer 
end of the lever arm to contact and engage the ratchet teeth of the 
arcuate bar and lock the lever arm in place against return rotative 
movement, whereby the flow controller is maintained in a selected rotative 
position. 
A still further object of the invention is to provide a tubing clamp with 
visual means to record and reinstitute the same flow rate, upon removal 
and reinstallation of the clamp by means of the arcuate bar having indicia 
markings along its entire length, which indicia or indicators serve as a 
memory device relating to the position or placement of the lever arm when 
the tubing clamp is dismantled. 
A still further object of the invention is manufacture of the tubing clamp 
with simple, inexpensive manufacture of the clamp in a single one-piece 
structure with a single mold. A related object is to facilitate and 
simplify assembly, since the tubing clamp constructed as a single unit 
provides some assurance that all required parts are available at time of 
assembly. Furthermore, such a tubing clamp with one-piece construction can 
be packaged, marketed and sold as a kit. 
The subject invention therefore comprises an improved flow control device 
which overcomes the foregoing problems and others and allows for 
manufacture of a one-piece clamp in a mold for reduced manufacturing costs 
and for assurance that all components of the clamp are together at time of 
assembly. 
The tubing clamp when manufactured as a one-piece structure is forms a 
molded array of the clamp, which includes a flow controller detachably 
coupled to the body of the clamp by a tear tab for easy separation, 
insertion and use as a movable component of the clamp. The tubing clamp is 
capable of being opened for sidewise insertion of tubing and flow 
controller and then closed to retain the controller in position overlying 
and bearing upon the tubing. 
In accordance with one aspect of the invention, the tubing clamp of the 
type referred to above is comprised of an elongated U-shaped body member 
(when the body of tubing clamp is in closed arrangement), having two side 
walls and a bottom wall, the first side wall durably affixed to the bottom 
wall and the second side wall hingably affixed to the bottom wall, so that 
the second side wall of the body may be opened for insertion of tubing 
upon the bottom wall. The flow controller can be removably placed in the 
channel defined by the body with the controller overlying the tubing. The 
second side wall is then closed in position approximately parallel to the 
first side wall, thereby and the flow controller can be rotated within the 
body. In another aspect of the invention, the tubing clamp also has 
retaining means for retaining the flow controller in a selected flow 
controlling position. 
In accordance with a further aspect of the invention, a flow controller 
having first and second ends has a cylinder portion with a cylindrical 
surface at the first end. The cylindrical surface of the flow controller 
overlies and is in direct contact with the tubing while rotatably mounted 
between the two side walls of the body. A pair of journal ends project 
axially from each of the sides of the flow controller and extend into 
opposed longitudinal slots grooved on the inner surfaces of the side walls 
of the body. The slots are approximately parallel to the tubing lying in 
the channel. 
The longitudinal slots have a plane, and that plane passing through the 
longitudinal slots, if extended, would intersect the plane of the bottom 
wall, if extended. Each slot has a notched opening to facilitate insertion 
of the journal ends into the slots, so that the slots are disposed for 
slidably and rotatably mounting the flow controller between the side 
walls, and upon closing the second side wall, to hold the controller and 
body members together in assembled rotative relation. 
In a first modification of the invention, the bottom wall is elevated at 
one end, so that as the flow controller rotates and travels in the 
channel, it tightens against the elevated end of the bottom wall to 
squeeze and constrict the underlying tubing. 
A still further aspect of the invention comprises a row of gear teeth 
projecting from one side of the flow controller to engage gear teeth which 
project from the second side wall, so that as the flow controller slides 
and rotates within the channel, it engages the gear teeth, travels along 
the bottom wall and tightens against the bottom wall to squeeze the 
compressible tubing against the bottom wall. 
The second side wall is hingeably affixed to the bottom wall with clamp 
material to allow repeated opening and closing of the second side wall. 
The hinge is preferably constructed of a polymeric material which 
increases in strength upon continued and repeated flexion. One such 
material is polypropylene. 
The tubing clamp of the invention includes anterior and posterior braces 
which project from either end of the first side wall of the body. The 
braces are connected at their ends by an arcuate bar which is coaxial with 
a line passing transversely through the center of each of the longitudinal 
axes of each of the slots. 
A pair of lock plates project from the outermost ends of the second side 
wall, and a pair of lock arms project from the anterior and posterior 
braces near the ends of the first side wall; and flexible locking caps are 
provided at the end of each lock arm. The locking caps are disposed to 
receive and grip the lock plates projecting from the second side wall to 
secure the second side wall in closed position essentially parallel to the 
first side wall. 
In yet another aspect of the invention, the lock arms are disposed at a 
distance from the bottom ramp so that insertion of the compressible tubing 
over the bottom ramp and under each lock arm effectively guides and holds 
the compressible tubing in the channel formed by the U-shaped body member. 
Further objects and advantages of the invention will be apparent from the 
following detailed description of preferred species thereof and from the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The tubing 30 to be clamped for controlling flow is comprised of 
elastically compressible plastic tubing commercially known as Tygon (TM) 
tubing commonly employed in catheter systems. 
Reference to FIG. 1 indicates the clamp 10 in operative array with the body 
56 in closed arrangement. The section of tubing 30 is inserted in the 
tubing clamp 10 which in operation can be adjusted to compress and occlude 
the elastic tubing in the clamp to the extent necessary to provide the 
desired rate of flow, e.g., drops per unit time interval, through a 
respective tubing section. 
The entire tubing clamp 10 is constructed from one mold as a one-piece 
structure as shown in FIG. 3 and FIG. 4 including flow controller 24 
detachably attached to body 56 by a thin tear tab 32 formed of clamp 
material, to facilitate location and assemblage of components. When molded 
as such, the clamp is in a generally flat, inoperative or molded array. 
The clamp is made ready for use by assembly to form an operative array of 
the clamp as seen in FIG. 1 and FIG. 2. The clamp 10 is comprised of a 
body 56, the body having a U-shaped form as viewed from one end of the 
clamp, when the clamp is in the assembled or operative array of FIG. 1 and 
FIG. 2. A bottom wall 12 and a first side wall 16 and second repositional 
side wall 18, together define a channel 28 open at the top and at both 
ends when the body is in a closed arrangement. 
The second side wall 18 is adapted to be opened, thereby forming an open 
arrangement of the body, see FIG. 6, for insertion of tubing 30 to lie 
upon the bottom wall 12 and a flow controller 24, to overlie the tubing, 
the controller slidably, rotatably and mechanically mounted to side walls 
16, 18 of the body 56, such that the flow controller 24 may slide and 
rotate relative to the body 56. 
Flow controller 24 has first and second ends with a cylinder portion 40 at 
its first end, the cylinder portion 40 having a cylindrical surface 41 
which overlies and directly contacts the compressible tubing 30 and bears 
upon the tubing lying upon the bottom wall 12. 
The flow controller 24 has journal ends 42 projecting axially from each 
side thereof, each journal end extending into a slot 36, 37 on the 
opposing side wall of the body 56. At one end of each of the slots 36, 37 
there is a notch 38 wider than the slot itself to facilitate insertion of 
the journal ends 42 into the slots 36, 37. 
The longitudinal slots 36, 37 form the plane 66 of the slots, when the 
clamp is assembled in operative array with the body in closed arrangement 
or U-shaped former i.e., the plane passing through both longitudinal 
slots, which is essentially normal to the plane of each of the side walls 
16, 18. In the most general embodiment of the invention, the plane 66 of 
the slots, if extended, intersects with the plane of the bottom wall 68, 
if extended. The flow controller 24 also has a row of gear teeth 34 
projecting from one side thereof to engage a row of gear teeth 35 
projecting from the opposed second side wall 18. 
In the first modification of the invention, there is a slight elevation of 
the bottom wall 12 toward the anterior end 14 of the bottom wall 12, so 
that as the gear teeth 34 of the flow controller 24 engage gear teeth 
projecting from the second side wall 18, and as the cylinder portion 40, 
moves in the channel 28, held in position by its journal ends 42, 
projecting into the slots 36, 37 the cylinder portion 40 rotates and 
advances along the gear teeth 34, 35, to the elevated end of the bottom 
wall 12; and the cylindrical surface 41 gradually tightens against the 
elevated end of the bottom wall 12 to squeeze and constrict the 
compressible tubing 30, thereby controlling flow within the tubing. 
A hinge 22 for affixing the second side wall 18 to the bottom wall 12 is 
preferably formed of clamp material. The preferred type of hinge material 
should be capable of repeated flexing movements while retaining its 
function as a hinge. Such a living hinge may be constructed using a 
polymeric material. A particular material having this property is 
polypropelene. 
A pair of lock plates 20 extend from either side of the second side wall 
18. A lock arm 50 projects from both the anterior and posterior braces 44, 
46. The lock arms 50 are essentially normal to the first side wall 16 and 
have somewhat flexible locking caps 52, at the second end of each lock arm 
50. 
When the second side wall 18 is open, the body 56 may be said to be in an 
open arrangement; and when the second side wall 18 is closed, the body is 
then in a closed arrangement. The locking caps 52 are disposed to receive 
and grip the lock plates 20 projecting from the second side wall 18 to 
secure the second side wall 18 in closed snap-locked position essentially 
parallel to the first side wall 16. The body of the clamp is then in 
closed arrangement. (See FIG. 1, FIG. 2 and FIG. 7.) 
The actuating arm or lever arm 26 on the flow controller 24 extends 
radially outward from the cylinder portion 40 of the flow controller 24. 
The anterior and posterior braces 44, 46 project outward on opposite sides 
of the first side wall 16. 
Braces 44, 46 are spaced apart around the body 56 a distance corresponding 
approximately to the extent of angular rotatable movement of the lever arm 
26 required to move the lever arm, and consequently the cylinder portion 
40, from a position wherein the tubing 30 lying on the bottom wall 12 is 
not constricted to a position where the tubing is fully constricted. At 
the latter point, the tubing 30 is then fully compressed to a flattened, 
completely occluded condition. 
The braces are connected at their outer ends by an arcuate bar 48 centered 
on an axis passing transversely through the center of the longitudinal 
axes of each of the slots 36, 37. Lever arm 26 may be constructed so that 
it does not project over or does not override arcuate bar 48. In that 
configuration, the flow controller 24 is held in a predetermined, selected 
position by its frictional contact with the underlying tubing. However, in 
the preferred embodiment, lever arm 26 of the flow controller 24 does 
extend sufficiently to be in contact and engage arc,ate bar 48. 
And in that preferred embodiment, lever arm 26 is held in selected flow 
controlling position by a series of ratchet teeth 60 located on and along 
the length of the arcuate bar 48 engaged by a detent 62 located on the 
outer end of the lever arm 26, which detent engages ratchet teeth 60 to 
lock the lever arm in place against return rotative movement. To this end, 
locking faces 64 of the ratchet teeth 60 lie in respective axial planes 
which include the turning axis of the lever arm 26 and which face opposite 
the direction of return rotative movement of the lever arm to the 
inoperative or starting rotative position of lever arm 26. 
When the lever arm 26 is rotated relative to the arcuate bar 48 by the 
manual operation of lever arm 26, in a direction to set the cylinder 
portion 40 in the prescribed flow controlling position, the detent 62 on 
lever arm 26 in ratcheting engagement with the ratchet teeth 60, rides 
over the successive ratchet teeth 60 and catches behind the locking face 
64 of that ratchet tooth 60 at the desired rotative position of the lever 
arm 26 relative to the body member 56. The lever arm 26 is thus held in 
selected flow controlling position. 
Disassembly of the tubing clamp 10 may be accomplished by applying force at 
the ends of anterior and posterior braces 44, 46 to bow the body member 56 
thereby forcing lock caps 52 away from lock plates 20 to unfasten the 
second side wall 18 from snap-locked position whereupon the second side 
wall 18 can be opened an amount necessary for removal of the flow 
controller 24 and tubing 10 lying on the bottom wall 12 in the channel 28. 
In FIG. 3 and FIG. 4, the tubing clamp is illustrated as the device would 
be manufactured as a one-piece structure by a single mold, with the flow 
controller 24 detachably attached to the second side wall 18 with a tear 
tab 32. The one-piece construction of the clamp 10 to form a molded array 
of the clamp expedites assembly and installation of tubing in the clamp, 
since all components are together at one location. 
As shown in FIG. 6, the second side wall 18 is opened and the cylinder 
portion 40, with cylindrical surface 41, in contact with, but bearing only 
slightly on, the tubing 30 lying on the bottom wall 12. When the lever arm 
26 of flow controller 24 is at that position, tubing 30 is unrestricted 
and open. Movement of the lever arm 26 (toward the OFF indicator 74), 
causes rotation of the cylindrical portion 40 of the flow controller 24 to 
constrict tubing 30 for precise flow control by gradual adjustment. A 
small movement of the lever arm 26 results in a still smaller movement of 
the cylindrical surface 41. 
Thus, the prescribed rate of flow is attained by gradually constricting the 
tubing 30 and that flow rate can be recorded by indicia (not shown) 
inscribed along the length of the arcuate bar 48. 
The occluding of the tubing 30 begins near the start of the angular 
movement of the lever arm 26 and associated cylinder portion 40 relative 
to the body member 56 in a direction to constrict the tubing 30, whereupon 
the flow within the tubing proceeds at a progressively slower rate during 
continued movement of the lever arm 26 and, concomitantly, the cylinder 
portion 40 relative to the body member 56. 
The tubing clamp 10 described above is preferably constructed in a molding 
process by use of a single mold, wherein a polymeric material, such as 
polypropelene, is heated and formed in the mold which defines and forms 
the tubing clamp described above. The clamp thus constructed is in a 
relatively flat, inoperative or molded array, shown in FIG. 3 and FIG. 4. 
The clamp can then be packaged in a sealed container or envelope (not 
shown). The packaging should preferably be in a sterile or clean room 
environment, by vacuum process. The envelope or package may be a blister 
pack, adapted to be opened by hand and having a transparent side to see 
the tubing clamp within. 
When in use, the clamp 10 is removed from the package and the tear tab 32 
is broken to separate the flow controller 24 from the body 56 of the clamp 
in order to assemble the clamp and form it in an operative array. 
In order to form the clamp in operative array, the tubing 30 is first 
positioned over the bottom wall 12 and under the lock arms 50. The flow 
controller 24 is then installed into the body to overlie the tubing with 
the cylindrical surface 41 of the cylinder portion 40 of the controller 
contacting the tubing. 
The open second side wall 18 is then repositioned while journal ends 42 of 
the controller are inserted into slots 36, 37 on each side wall to form an 
operative array of the clamp. 
The second side wall is snap-locked by pressing the lock plates 20 against 
the flexible locking caps 52 until the locking caps receive and grip the 
lock plates to form the closed arrangement of the body. 
The lever arm 26 is then actuated by manual rotation until gear teeth 34 
which project from the flow controller engage the gear teeth 35 projecting 
from the second side wall, so that the cylinder portion of the flow 
controller travels across the bottom wall and squeezes the compressible 
tubing against the bottom wall, thereby constricting the tubing to a 
desired flow rate. 
The position of the lever arm at the desired flow rate may then be 
recorded. This record can be done by a simple pencil or marker line on the 
arcuate bar adjacent the lever arm, such that when the clamp is 
disassembled and then reinstalled, it can readily be reset to the desired 
or prescribed flow rate. 
While the preferred embodiment of the invention has been disclosed herein, 
it will be appreciated that modification of this particular embodiment of 
the invention will be resorted to without departing from the scope of the 
invention.