JP2000334039A - Plastic roller type clamp assembly and mold collection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce burden of adjusting a clamping force, to improve clamping of tubes, and to reduce the production cost by setting cross-sectional widths in such that the bottom wall is thicker than the sidewall, the sidewall is thinner than the top wall, and the top wall is thicker than the bottom wall. SOLUTION: Thickness of a sidewall 58 is 1.1 to 2.3 times that of a non- deformed (nominal) soft plastic tube wall. Thickness of top walls 51, 52 is 2.5 to 4.5 times that of the non-deformed soft plastic tube wall. Thickness of a bottom wall 60 is 0.4 to 1.0 times that of the top walls 51, 52. Thickness of the sidewall 58 is 0.3 to 0.8 times that of the top walls 51, 52. A clamp housing 50 has a ratio of weight to length of less than 0.48g/cm, 2.28 to 3.18 mm in inside diameter, 3.0 to 6 mm in outside diameter, 65 to 90 in Shore D hardness, and has a clamping strength enough to completely close a PV tube having non-shrinkable wall of 0.5 to 1.0 mm in width.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

RELATED APPLICATIONS This application is a related application of the applicant's earlier application serial number 08 / 646,214, filed on May 7, 1996, filed on November 19, 1998. Applicant's earlier application serial number 09 / 196,920
No., related application.

[0002]

FIELD OF THE INVENTION The present invention relates to roller clamps for intravenous (IV) sets and more particularly to reduce the effort required to adjust the degree of tube tightening. Improve the grip on the tube by following the preferred housing dimensions described below,
And has a unique combination of advantages, including the effect of reducing manufacturing costs. V. An improved roller clamp for a set.

[0003]

BACKGROUND OF THE INVENTION An intravenous drip set is approximately 1940
During the period from 1950 to 1950, it evolved from being reusable to being disposable. Earlier, techniques were developed to produce and store medical grade liquids for infusion into human veins. The liquids were, for example, water and dilute solutions of saline, dextrose, and other liquid nutrients and certain drugs. These liquids were stored in sealed glass containers and dispensed using sterile surgical rubber tubing. Tubing and other infusion parts were usually re-sterilized and reused. Control of the rate of liquid administration was adjusted by varying the degree of tightening of the rubber tubing. Various clamping clamps have been developed for this application.

With the increasing use of medical grade polyvinyl chloride (PVC) tubing and the need to reduce or eliminate the serious patient / hospital problem of cross-contamination,
A disposable infusion set was introduced. This eliminated the problem of cross-contamination, but introduced new problems. The problem is that the flow rate changes over time, i.e., the flow rate changes over time with the initially set desired flow rate. The clamped plastic tubing had creep or cold flow problems when clamped, which resulted in a change in flow over time. Usually this change
(About 40% during the first 10 minutes, then increase)
It was large and in most cases the flow rate was decreasing.

The first clamping clamp (which did not operate in parallel) that addressed the problem of time-varying flow rates was described around 1967. After that year,
A series of improved parallel-acting clamps have been introduced and a number of major improvements have been made. The main improvement of such newly developed clamps was ease of adjustment until 1967, but since 1967 they are usually easier to use and / or adjustable and time consuming. Even though the flow rate hardly changed.

[0006] Separately, improvements have been made in terms of better clamping of the tube by the clamp. This is because if the clamp is accidentally dislodged, the flow rate will increase and, in the worst case, it will come off, which can be life-threatening or fatal.

[0007] As with most products used in large quantities, the problem of manufacturing costs has usually been an underlying factor. Typical factors that are effective and utilized for cost reduction are: (1) reducing components to save material, (2) using lower cost materials, and
(3) In order to keep labor costs low, assembly of parts is facilitated.

[0008] Injection molded plastic is a common method for manufacturing disposable clamps. Typically,
Plastic materials such as acrylonitrile butadiene styrene (ABS) resin or polystyrene (PS) can be used with rubber additives. A
BS materials are usually denser than polypropylene or other plastics that have been used. Preferred materials for the present invention are ABS or PS, or PS to which butadiene containing polymers and other rubber-like materials has been added, if possible.

Due to the economic pressure to reduce or reduce the cost of health care, the use of large volumes of infusion sets, and the increasing cost of plastic resins, finding clamps such as: Interest has greatly increased. That is, (1) ease of use and (2) reducing the change in flow rate over time,
And (3) Obtained by the obvious steps of meeting the need for a tighter grip on the tube and of reducing the size of the parts, increasing the number of production cavities and / or using a lower cost resin. A clamp that can be manufactured at a lower cost than that of a clamp.

Sometimes I. V. After a single use, the I.V. V. Roller clamps that are typically disposed of with a set are well known. It is primarily designed to regulate the flow of liquid through flexible and pliable tubes of soft plastic, usually made of hard-to-extract polyvinyl chloride. The degree of tube tightening
It is typically used to reduce the flow rate and adjust the flow rate to a desired value, typically measured in a few drops per minute when using a drip chamber, which value is preferably the liquid of interest. Represents a predetermined rate to be administered intravenously at that rate. These clamping clamps are also used as on / off devices, i.e. to pass and stop the flow. Of course, once the clamping clamp has been set, it must be able to precisely control its flow rate over time and to completely shut off the flow when desired.

A typical prior art clamp is:
According to Adelberg's prior patent. No. 4,047,6, 1977.
No. 94; No. 4,013,263 of 1977; 197
No. 3,685,787 in 2 years; 5,0 in 1991
14,962; 1988, 4,725,037 and 1984, Re 31,584, the disclosures of which are incorporated herein by reference.

Generally, there are two basic types of IV set roller clamping clamps. One is a "tilt ramp" clamp, the other is a "parallel actuated" clamp, the wheel of which moves approximately parallel to what is commonly referred to as the clamping surface. In each case, the clamp essentially comprises a housing, which houses the wheels (rollers) typically supported by the housing, and a plastic tube, inside the housing, at the bottom of the housing or It is stored between the clamp surface and the roller.

Regardless of the type of clamp, one end of the roller has a "full flow", i. V. There are positions where there is a flow that is not regulated by the maximum flow capacity of the set.
Another location on the roller, typically remote from the full-flow position, is a no-flow position where there is no flow through the tube. This is typically a blocking position. Depending on the clamp, there is another blocking position, more properly the locking position,
In this position, the movement of the rollers is reliably stopped, as described below, so that no flow through the tube occurs. Between the full-flow position and the no-flow position, there is typically a region of roller movement, or so-called "flow control" region, over which the flow can be controlled.
The length of the flow control area will be less than the maximum distance the roller will travel, especially in the axial direction, if there is a locking position.

In the case of an inclined ramp clamp, flow control is achieved by the principle of an "inclined ramp", wherein the rollers are pushed up by the operator's fingers above the ramp, so that the rollers and the tube are Clearance between the overlying opposing housing surface is reduced,
Thereby, the desired degree of tightening is obtained, and thus the flow rate can be controlled. As the roller or wheel advances, the clearance between the roller and the housing surface on which the tube overlies decreases, and at its distal position,
Complete blockage (of a clamped tube) is obtained.
In a typical flow setting of the clamp, the lumen of the tube collapses completely in a large central region of the tube cross section, where the radius of curvature of the tube is large, and a pair of lumens is formed on both sides. On both sides, the radius of curvature of the clamped tube is the smallest, and therefore exhibits greater resistance to clamping. After the roller has been brought to its new position, why the newly formed lumen remains collapsed and reduces flow is explained by the cold flow or creep phenomenon of the plastic tube.

In a parallel-acting (dual-acting) clamp, the effects of creep or cold flow are reduced or ideally eliminated, but this is due to the wheel being located somewhere in the flow control area of the housing. A section to guide the tube, thereby forming a tube clearance,
This is achieved by allowing at least one, and usually both, lumens formed on one or both outer edges to be completely clamped and blocked at some particular tube cross section. Is done. The flow rate can be varied by changing the cross section of the lumen formed anywhere. Precise control in any tube cross-section is achieved in the tube cross-section by varying the ratio between the fully tightened blocking portion and the other portion that remains open, in that tube cross-section. This is because there is a clearance portion in the bottom, the housing or the wheel that is not tightened or weakly tightened. The actuation or movement of the rollers may not be exactly parallel to the opposing clamping surface of the housing, and need not even be approximately parallel. The criteria for a clamp that operates in parallel is to have a clearance between the roller and the housing that serves to completely tighten and shut off the local part of the tube, and that the tube be in contact with or close to the tube. Positioned opposite a section of the housing surface or, depending on design, with an outer wheel surface that allows an open lumen to be formed therein and / or forms a relief to facilitate its formation Having the rest of the tube positioned on the part.

In the case of a parallel-acting type of clamp, the rollers in a typical station completely tighten and close off a portion of the tube, and the escape in the housing usually provides the desired degree of tightening or partial tube closing. Used to effect closure. Although the term "parallel" is used, it does not indicate geometric parallelism,
Nor is it intended to indicate that the configuration in which the rollers move is exactly parallel throughout the range of movement. Such "parallel" operation is required only in the flow control range of the roller movement. In fact, the clamps acting in parallel are driven by the movement of the roller and the opposite surface on which the tube lies and is clamped there as a result of a "draft" used, for example, in injection molding designs as described below. Can, and usually does, include a small relative angle. However, this relatively small angle is, by itself, insufficient to significantly affect the change or control of the flow velocity and is not intended. This is because the change in clearance between the roller and the surface on which the tube is clamped is not sufficient to directly change the cross-sectional area of the flow. This is in contrast to a ramp ramp clamp. Also in the region before the flow control position of the housing and after the shut-off or no-flow position, in contrast to the locking position, the clamping action may still be non-parallel in its construction. Since there is no flow control in these regions, even the substantially parallel actuation described herein is not relevant or necessary.

The design of a parallel-acting roller clamp, in which only one side of the tube is fully tightened and blocked, has one lumen that would otherwise be formed and exhibit creep or cold flow. Complete tightening may provide an improvement in clamps designed to obtain good performance with respect to time-varying flow (time-varying flow), but more advanced designs may require a tightened soft Fully tighten and shut off both sides of the plastic tube.

A feature that distinguishes a parallel-acting (dual-acting) roller clamp from a ramp ramp clamp is the manner in which flow control is achieved. Most of the roller clamps that operate in parallel achieve flow control by completely tightening and shutting off one side, usually both sides, of the tubing throughout the range of flow control, and the position of the roller within the area of flow control Varies the ratio of the unclamped or partially clamped open portion to the fully clamped blocking portion of the tube. It should be noted that for a given tube cross-section, it is only necessary to completely tighten and shut off one or both sides, not the adjacent sections of the tube, only within the range of movement of the rollers, which is in fact the area that controls the flow. ,it is obvious.
In the case of an inclined ramp clamp, flow control is achieved by varying the clearance between the roller and the opposing clamping surface. Thus, true parallelism may not be present in a "parallel-acting" clamp, but until the degree of non-parallelism substantially affects a change in tube lumen or a corresponding change in flow rate. Obviously, the degree is not so great as to change the clearance. This is especially true if one or both sides are completely tightened and blocked over the range of movement of the rollers in the flow control area.

One typical arrangement for ensuring that one or both sides of the tube are fully clamped and shut off is the bottom of the roller and the opposing surfaces of the housing against which the tube is clamped. Is to provide a clearance between them. This usually does not exceed twice the thickness of the unclamped tube wall,
Often, less than twice the wall thickness of the tube. In general, a clearance of less than twice the thickness of the wall works satisfactorily to ensure that one or both sides are completely tightened and blocked. Again, it will be appreciated that this defined clearance must exist only in the flow control region. In fact, this clearance may be wider at the inlet end of the housing and somewhat smaller near the outlet end of the housing, especially when a separate shut-off lock is present.

In a "parallel-acting" clamp,
The clearance between the roller and the opposing clamping surface of the housing may or may not change with the position of the roller, but this change in clearance with respect to the position of the roller will reduce the size of the lumen formed. There is virtually no control. The control is then effected by varying the ratio of the clamped and blocked wall portion of the soft tube along the control portion of the housing to the non-clamped portion.

In the design of the ramp ramp clamp, as the roller is advanced, the central section of the tube being clamped may be lowered and completely collapsed and blocked, but between the roller and the opposing housing surface. Clearance is varied to (1) be large enough to form a lumen, usually on one or both sides of the tube, and (2) provide the desired lumen size and corresponding flow rate.

In less common parallel-acting clamps, there is a flank on the roller surface. It is a common feature of this type of clamp that the open area of the tube cross section changes as the roller moves and the size of the open area is related to the configuration of its flank of the clamp surface. As is known, the flank can be of various configurations, may be offset on one side of the housing, and beneath the tube or, usually, of different width or depth. Alternatively, they may be arranged in another place where both are different. Its function is to change the open area of the tube flow in response to the movement of the rollers. In fact, by varying the lumen formed, the flow rate can be varied, and various parallel-acting devices have this general feature. For the purposes of the present invention, the expression "acting in parallel" refers to a clamping clamp comprising a roller, a housing and means for changing the lumen of the formed tube to change the flow rate, said clamp comprising: Means a clamping clamp in which there is some form of clearance on the roller surface or on the housing or on the clamping surface, and the roller moves parallel to the clamping surface with the concept of translation described above. Is intended to be

In virtually all types and types of clamping clamps using rollers and housings,
The axle of the roller squeezes the guide surface as the position of the wheel or roller changes and when it is in a position that provides the desired degree of tightening.

There are specific requirements for the clamping clamp to which the present invention pertains, but some of the important requirements are as follows: (1) The upper surface of the housing is Must be designed to withstand compression by the axle. (2) The upper surface of the housing, when subjected to an upward force, for example caused by the axle of the wheel to be tightened,
Must be designed to withstand outward rotation and resist deflection. (3) The side walls of the housing must be designed to withstand pulling. (4) The lower surface of the housing must be designed to resist deflection and operate under compression, and is ideal for variable width relief and elements that are lifted to fit. Must provide a good location.
If this raised element is used, its height, width and spacing can be varied. (5) The housing must be made of injection moldable plastic and have a cross-sectional area designed to facilitate the flow of injection molded plastic to fill the entire steel mold cavity. It must provide the stiffness required for removal from the mold, subsequent assembly, and for normal use.

When the parallel-acting clamps were mass-produced and introduced to the market around 1975, the length of the housing was approximately 2 inches (corresponding to approximately 5.08 cm).
The competing tilt lamp clamp housing measures approximately 1.4 inches long (equivalent to approximately 3.56 cm).
Met. Parallel-acting clamps occupy a large share of the market due to better performance compared to tilted lamp clamps, and by 1978, I.S. V. One of the two largest companies in the United States (Abbott Labs, the other with Baxter Labs) for products that require clamps for use in sets
Traxenol (Baxter Travenol) accounted for essentially all of its sales. Around 1983, Baxter began using longer, patented clamps. Then other companies, such as Cutter (which actually started earlier), McGaw, IVAC, Borla, etc., were 2 inches (equivalent to about 5.08 cm). A clamp with a housing was introduced, thus creating a trend regarding the length of the clamp.

As the use of longer clamps has become more widespread, manufacturing costs have substantially increased in most of the market, but many of these longer clamps have been replaced by patented parallel-acting clamps. It did not result in improved performance. Some of these companies have simply followed the trend of longer housing lengths. In the case of Abbott's parallel-acting clamp, its length was functional. It is that, in addition to providing a time-invariant flow rate and a tighter grip on the tube, the longer roller movement allows for a finer adjustment of the degree of tightening and thus of the flow rate. Was.

[0027] Later, it was the heavier clamps that the market introduced to follow the trend of longer lengths, but it is clear that these relatively heavy clamps result in increased manufacturing costs. Received little attention and was given low priority. These cost increases are substantial, given the number of clamps used per year.

Recently, the cost of manufacturing roller clamping clamps and many other plastic items has risen sharply, with the cost portion of plastic resin accounting for five times the manufacturing cost.
Although it was about 0%, the cost of this plastic resin now accounts for a large or major part of the manufacturing cost. At present, the proportion of molding costs is relatively small, and the proportion of raw material costs is relatively large and growing. Thus, if the moldable and usable parts could at least be redesigned to provide the same functionality and utilize very little plastic resin, there would be significant savings in production costs. .

Most shaped clamps have a housing whose wall thickness cross section is substantially uniform throughout. During the design of the clamp, such design parameters first focus on important internal surface configurations, such as the clamping surface of the housing, the wheel axle guides, the width of the wheel slots, and then the uniform wall Completing the design by simply specifying the thickness allows easy identification.

The new shaped clamp of the present invention not only provides the desired type of clamping (such as the side wall of a tube that is fully clamped and shut off when operated in parallel), but additionally. , Incorporating strength (such as flexural modulus) and molding design (of an injected plastic that completely fills the passage) and has a structure that significantly reduces the material required for each clamp.

Currently, typical roller clamps have dimensions in the following ranges: That is: (1) a wheel outer diameter width of 1.3 to 1.8 times the nominal tube outer diameter;
A greater range of housing wall thicknesses, and (3)
It has a uniform wall thickness over the entire cross-section, the cross-section being the same over the working length of the housing in which flow regulation takes place (area of flow control).

An obvious way to reduce the weight of a part is
This is to reduce the length of the housing. However, this is not desirable. This is because a portion of the length of the housing, usually at its wide end, is necessary to facilitate the introduction of the wheel and make the combination operable. The remainder serves primarily to provide a reasonable range of travel for the wheel, thereby gradually tightening the tube at any location along the clearance or control section of the housing.

It is not practical to reduce the width or height of all or most of the cross section of the clamp housing. This is because it makes it difficult to surround and clamp a given radius of the flexible plastic tube.

The current clamping clamp housing is:
The outer diameter of the tube to be tightened with the clamp,
It has a uniform wall thickness in the range of 0.3 to 0.5 times.

There is a practical minimum on the length of the housing. For commonly sized tubes having an outside diameter in the range of 3.25 mm to 4.5 mm, the minimum length of the housing is in the range of 23 mm to 55 mm, or approximately seven times the outside diameter of the tube. Or 25 times. The wall thickness of the clamp housing is typically 1.2 m
m to 1.7 mm, or approximately 0.2 to 0.5 times the outer diameter of the tube. Most importantly, the housing of the clamp is typically of uniform wall thickness. This (ie, uniform housing wall thickness) is clearly for the following reasons. That is: It is easy to identify; It is a conventional design parameter for injection molded parts. 2. Uniform wall thickness facilitates filling of steel mold with injection plastic; This is because most clamp designs do not care much about the expected mechanical deflection variations of the plastic housing when stressed in connection with tube clamping.

The mechanical deflection (strain) depends on many parameters, but for a given plastic resin material, which is a preferred material in the present invention, for example, ABS (acrylonitrile-butadiene-styrene), the stress To some extent, as well as the type of stress (tension, bending, compression, torsion, etc.). A good design minimizes deflection under load, or, in some designs, allows deflection, but if such deflection is within or exceeds the elastic limit. Minimizes the extent to which the elastic limit is exceeded or the amount of deflection.

If the clamp housing is ready for use, ie, V. When combined with a set of wheels, clamped tubes and other components, the clamp will have the expected deflection,
The amount depends in part on the type of stress applied (tension, bending, etc.). The side walls of the clamp housing are predominantly tensioned, while the upper edges or walls are firstly subjected to bending or flexing forces, and the roller wheel axle is mounted on its upper surface. The pressure applied to the location where it comes into contact results in a secondary component, local compression. In the case of an injection-molded clamping clamp having one or more housing wall sections subjected to a tensile force, according to the invention, the part comprises a top and a non-primarily applied tensile force. A smaller cross section is required compared to the bottom wall. The distortion or mechanical deflection of the housing when used to clamp the tube is for the following reasons. That is: First, due to at least two modes of bending or bending of the upper edge or upper wall of the housing; Second, by pulling the side walls of the housing; 3. To a lesser extent, the local compressive force exerted directly by the wheel axle on the upper edge of the housing where the wheel axle contacts; Due to the pressure exerted by the outer circumference of the wheel against the lower part of the surface of the housing through twice the thickness of the wall of the soft plastic tube to be clamped.

Turning now to the prior patents relating to clamps, most patents have a side wall that is thinner than the top or bottom wall of the housing and a cross section that is thicker than the bottom wall. The upper wall is not mentioned in writing. Further, the drawings of some patents relating to roller clamps show various configurations but do not teach why the wall thickness dimensions are as shown. For example, U.S. Pat.
No. 411,731; No. 1,959,074; No. 2,5
No. 95,511; No. 3,135,259; No. 3,18
Nos. 9,038 and 3,289,999 appear to show structures having uniform wall thickness. U.S. Patent Nos. 3,099,429; 3,215,394;
Nos. 3,215,395; 3,297,558 and 4,340,201 include drawings that can be interpreted as showing thin wall structures. Of these, U.S. Pat. No. 3,099,42 issued to Broman
Issue 9 deserves special mention.

Browman illustrates a clamp having thinner top and side walls, the clamping surface or bottom wall of which appears to be thicker than the side walls.
In Bromann, the guide surface is of the same thickness as the thin side wall and is much thinner than the clamping surface. Bromann does not state any weight savings or strength considerations (deflection, tension, etc.). There is no description as to why the wall thickness is as shown, and thus the thickness of the cross-section at various locations appears to be merely arbitrarily illustrated.

When using an injection-molded housing used for roller clamping, its side walls usually have
A tensile force is applied. On the other hand, its top and bottom walls are subjected to flexing or compressive loads, but those walls to which a tensile force is applied carry a higher load, so that the walls required for a good design The thickness is usually thinner for the side walls. Nevertheless, it is interesting that none of the cited patents describes a thinner side wall. The applicable patent is 1
No. 3,974, Dabney et al.
U.S. Pat. No. 4,340,201 to Becker in 1982; U.S. Pat. No. 4,475,709 to Becker in 1984;
9-year Karpisek US Patent No. 4,
No. 869,721; Forber, 1990
g) U.S. Patent No. 4,895,340; 1993
U.S. Patent No. 5,190,0
79; and 1979 German Patent No. DT28
No. 55572, and the like.

A German company, Clinico, manufactures roller clamps used in Germany, which are similar to those found on the US market and are 0.594 grams / cm. Weight to length ratio. This clamp has an average of about 10% thinner wall thickness than the U.S. clamp and is about 22% lighter in weight. This difference in weight is due in part to differences in the type of tube holder incorporated into the clamp housing. The tube holder is at the clamp end at the opening or input end of the clamp. In the Clinico clamp, the tube holder is much smaller than that of the U.S. clamp, and in addition, the Clinico clamp is ABS
It seems that the resin is molded from a resin having a lower density.

Many commercially available clamp housings have a length in the range of 5.2 to 5.7 cm, are molded from ABS or polystyrene, and have a length of 0.65 to 0.72 gm.
/ Cm weight to length ratio. In contrast, the clamp of the present invention can have a length of 5.6 cm and a weight-to-length ratio of 0.393 gm / cm with a similar measurement method. However, refer to the following description.

Accordingly, it is an object of the present invention to provide a clamping clamp that is easier to adjust, provides a firmer grip on the tube, and performs as well as clamps currently on the market. The present invention is to provide a clamping clamp whose section is thicker than the section of the bottom wall, whose side walls are thinner than the top wall and preferably smaller than the bottom wall, and which can be manufactured economically.

[0044]

SUMMARY OF THE INVENTION The object of the present invention is to V. An improved roller clamp for the set, more particularly the effort required to adjust the degree of tightening when the preferred dimensional relationship of the housing and the preferred relative dimensions are as described below. I. has the advantage of providing high performance by reducing and improving grip on the tube, and the unique advantage of substantially reducing manufacturing costs. V. This is achieved by providing an improved roller clamp for the set.

Accordingly, a preferred and practical method of the present invention is to selectively identify portions of the cross section of the clamp housing. An improvement according to the invention is to further vary the cross-sectional area depending on its position along the longitudinal axis of the housing. For example, the cross-section of a portion of the housing in an area designed to insert a wheel has reduced strength requirements. In this region, the wheel axle does not squeeze the opposing housing surface through the action of clamping the tube. Moreover, there is usually little or no clamping action of the tube in this area. In contrast, in the normally longer working section of the housing, the so-called flow control area, the structure is
One must anticipate the large forces resulting from the interaction of the wheel, housing, and clamped tube.

Thus, taking into account all of the factors mentioned in connection with stress and deflection, etc., the I.V. V. The new and unique clamp housing design and the new and improved roller clamp used with the set are for the flow control part, the housing having: That is: a. A thick section top edge or wall for the housing; b. A generally thin side wall housing, as described above; c. A thick bottom wall (but not as thick as the top wall or top edge) of the housing.

What is important is the relationship of the ratio of the cross-sectional thickness of the top wall to the cross-sectional thickness of the side walls, which, according to the invention, is in the range from 1.3 to 4.0. .

The upper edge or upper edge having a thicker cross section according to (a) is used to minimize the degree of at least two types of bending or flexing. This is aimed at minimizing this in thick sections, as such deflection may be large. The second objective of (a) above is to minimize the degree of local deflection or indentation of the housing surface, where the wheel axle just exerts a relatively large local force. .

(B) above is used to reduce the weight of the material of the clamp housing, but the fact that it is relatively less flexible under tension and the fact that this plastic wall is relatively It takes advantage of the fact that large tensile forces can be handled.

The above (c) is used to make the bottom wall stiff (not more than necessary) to deal with bending and flexing. The above parameter (a) is designed for a housing where a relatively large force causing bending and deflection is applied by the wheel axle.
Parameter (c) is designed to respond to a similar opposing force, which also causes bending and flexing, but since this force is transmitted and applied by a clamped section of soft plastic tubing, It is also more extensive because of its wider dimensions.

The greatest degree of deflection occurs:
This is when the wheel is centrally located between the two end supports of the housing, and therefore at approximately equal distances from the two end supports. Therefore, the axially central portion of the upper wall portion should be correspondingly thicker than the ends. However, this is not practical for injection molded parts. The reason is that there is no "draft angle" for the parts, which can shrink and hold the mold core tightly when injection molded in a conventional manner, which allows for the removal of newly molded parts. is there. However, as a practical compromise, designs are possible where the thickness of the housing wall is reduced near the small end of the housing, but not so much at the open end of the housing.

[0052] Creep or cold flow can occur in the clamp clamp housing and wheel (which is usually more likely in clamped soft plastic tubing). Creep or cold flow occurs because the applied load causes the part to exceed its elastic limit. If creep or cold flow occurs, the dimensions of the part can change over time without external changes in load. This leads to a time-dependent change in the flow rate of the liquid through the clamped tube. To avoid this undesired phenomenon, the load must be limited or the wall cross-section should be large enough to prevent exceeding elastic limits or to minimize stress (and Correspondingly strong). However, deflection must be expected because strain is usually accompanied by stress.
It is usually best to operate within elastic limits.

Since the parts described in this invention are made of plastic and are preferably molded, a "filled" section or tunnel is required in the part for proper injection molding. This is typically between 350 ° F and 500 ° F
This is to ensure that the molten plastic resin at a temperature in the range (equivalent to 177 ° C. to 260 ° C.) flows easily and fills the cavity quickly and completely. If this tunnel or filling section is too small,
The molten plastic cools too quickly and can "freeze" before it is completely filled. The viscosity of the injected plastic resin depends greatly on the temperature, but at low temperatures the viscosity is too high and partial filling may occur. Too large a tunnel or filling cross-section eliminates the problem of partial filling, but leads to making the part using excess (and expensive) plastic resin, and also the formation of the mold cavity. The time required to cool the injected plastic to a temperature that allows the part to be withdrawn and that maintains its newly formed shape (without distortion or the like) (and Therefore, the manufacturing cost) is unnecessarily increased. The longer the time you keep it in the mold,
The costs for molding usually increase linearly. That is, if the cycle time for manufacturing a molded part by the molding machine is doubled, the molding cost is also almost doubled.

As far as the molding operation and the molding design are concerned,
In the present invention, it is important to properly select and combine the size and location of the filling cross section or filling tunnel with a properly designed cross section. A part that is fully stiff or strong under the conditions of bending, flexure or tension, thereby providing the necessary strength that the part is required to exhibit at a later time, and a fully formed part Can be provided. Thus, a preferred mold shape for proper molding has an internal cavity and a core outer surface sized and positioned as follows and meeting the following discrete requirements. That is: (1) properly sized and properly positioned, but not large enough to unnecessarily increase the weight of the part and / or unnecessarily slow its production cycle Having a filling tunnel or section; (2) having a properly sized, properly positioned, flexing or pulling cross section that provides the desired strength, stiffness or deflection, not too large; (3) A suitable plastic that meets the other requirements of tensile strength and part integrity, but uses minimal plastic to keep the total weight low and to reduce cooling time for faster production time It has a wall with a thin cross section. The faster the production time, the more products can be produced for a given molding time period and machine,
Typically, doubling the cross-sectional area approximately quadruples the cooling time of the molded part and the corresponding cost for molding.

As explained above, the upper wall of the housing is required to have the required bending stiffness and to prevent excessive penetration (indentation) due to local forces on the wheel axle. Thickened to have strength.

By way of illustration, if the upper wall or rail has a thickness less than the minimum, the penetration of the wheel axle is too large, causing permanent deformation and through the clamped tube. The result is that the flow rate changes over time. This is due to creep or cold flow of the plastic forming the top rail / wall of the housing. This creep and cold flow results when the plastic used to mold the housing exceeds its elastic limit.
Excessive penetration will also make it difficult for the operator to position the wheel. This is because a deep axle requires a relatively large force to drive the wheel to a new location. A plastic material with a higher Rockwell hardness value will provide the best resistance to local penetration by the wheel axle, but the cost and ease of molding of the plastic material is higher for the higher hardness. In some cases, the benefits of value can outweigh the benefits.

According to the present invention, the upper wall or rail of the housing must withstand three types of deformation when used under load or during use. The main challenge is to resist bending over the entire length of the housing while applying the desired clamping force on the roller axle. In addition, as described above, the upper wall must withstand excessive wheel indentation of the wheel axle on the local surface of the upper wall, ie, on top of the trunnion groove. A third consideration is the resistance of the upper wall to outward rotation. Such rotation is caused by the wheel's
p out) ”, which will be described later. In each of these cases, it is important that the upper wall does not exceed a suitable elastic limit.

However, thicker wall sections generally require more time for cooling, a necessary step in injection molding. This longer cooling period results in higher fabrication costs due to longer molding cycle times. All of the above is true and true when the cooling is one-dimensional, for example, for parts having a small thickness compared to the other two dimensions.

However, if one other dimension, perpendicular to the thickness dimension, is comparable to that thickness, the cooling is effectively two-dimensional, and the time required for the cooling is much longer. Less. Therefore, to avoid excessive cooling time, the upper section of the thick wall must have a thickness comparable to its width. This provides for a faster two-dimensional cooling and a wide flow path for the injected molten plastic which facilitates the complete filling of the adjacent thin side wall sections of the housing. Two advantages are provided.

Another aspect of the present invention is that it allows relatively existing molds to be modified relatively easily to take advantage of the present invention. One feature is
In order to produce thinner side walls (which must withstand tensile forces in use) involves changing the injection molding cavity relatively easily by bringing the two cavity halves closer together. .

Another feature is that (1) the mold core is moved relative to the cavity, and (a) (to provide the required bending strength and resistance to penetration by the wheel axle).
Increase the thickness of the wheel axle guide part of the housing,
(B) positioning the injection molding gate for good flow of molten plastic; (c) greatly reducing the wall thickness of the clamping surface of the housing (due to its inherently large wall cross section); Allowing the two-dimensional heat transfer (cooling) to be introduced or maintained (to keep production molding cycle times low) where the inner wheel axle guide has a thicker wall cross section.

With respect to the housing, the cross-sectional area of the housing according to the invention, over the range of flow control, is as follows: The side wall thickness may be 1.2 to 2.2 times the wall thickness of the undeformed (nominal) soft plastic tube.
1. within the range (not 2.2 to 3 times); The thickness of the upper wall (wheel axle guide) is 2 to 3 times the wall of the undeformed soft plastic tube.
2. Three times (this is a typical range or thicker); 3. The thickness of the bottom wall is preferably smaller than (typically equal to) the thickness of the top wall; The thickness of the side walls is approximately 0.3 to 0.6 times (typically equal) the thickness of the top wall. As described above, the ratio of the cross-sectional thickness of the top wall to the cross-sectional thickness of the side wall is in the range of 1.3 to 4.0.

Further details are given below, and in this way the above-mentioned objects are achieved. While the present invention has many other advantages, and other objects, they will become more apparent by considering the various shapes in which the invention may be implemented. Some of such shapes are illustrated in the accompanying drawings, which form a part of this specification. These shapes are described in detail below for purposes of illustrating the general principles of the invention, but it is to be understood that this detailed description is not to be taken in a limiting sense.

[0064]

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, a prior art parallel-acting clamp 10 is shown for illustrative purposes, but it should be understood that the present invention is also applicable to tilted ramp clamps. Clamp 10 includes a housing 12 and a wheel in the form of a roller 14 having a wheel axle 16 that fits into a groove formed in an upper portion of the housing.
In this exemplary configuration, the housing includes a lower surface or bottom wall 17 which is
7 comprises a groove 18 shown for illustrative purposes as a V-shaped groove,
The space between the bottom of the roller and the surface 17 is tube 2
Zero and the flow of liquid through the tube 20 is controlled based on the position of the roller.

Most roller clamps have a simple wheel whose outer diameter width is equal to one-half the circumference of the tube to be clamped, and an axle projecting from both sides of the wheel. The housing channel typically has a bottom surface (top surface of the bottom wall) that is wide enough to accommodate both the tube to be clamped and the width of the clamping wheel. The housing side wall typically forms a lower side wall adjacent the bottom channel or wall. This lower side wall guides the tube to be clamped so that the tube is positioned between the wheel and the clamping surface of the housing. Aside from the housing channel or the housing bottom wall and opposite the wheel axle, the housing side wall includes a trunnion section for receiving and guiding the axle.

The upper surface of the inner trunnion wall is typically substantially parallel to the lower clamping wall (bottom channel or wall) of the housing (a parallel working clamp increases this parallelism, and a tilted ramp clamp has a higher degree of parallelism). Is reduced), and the upper portion of the wheel is interrupted to form a slot projecting therethrough. As a result, two generally different parts are usually found in the side walls of the housing. That is, a main lower portion and a smaller upper portion that includes the trunnion and the trunnion side end walls. The trunnion has a trunnion-side end wall facing the outward end of the wheel axle and a gap (height) just to accommodate the diameter of the wheel axle. Each of the upper and lower portions of the trunnion typically has a span (width) comparable to the protrusion length of the wheel axle.

The inner upper surface of the trunnion often extends substantially axially of the clamping surface or bottom wall of the housing and, when the tube is clamped, subjected to local compressive loads imposed by the protruding wheel axle. Endure. In order to distribute this localized axle load, the wheel axle is shaped cylindrical with a uniform diameter through its protruding length. Such concentrated bearing loads will be even more concentrated if the diameter of the projecting axle is not uniform.

Thus, the upper surface inside the trunnion needs to have a substantially accurate 90 ° angle where it joins the inner surface of the vertical side wall of the trunnion. Stress concentrates at this right angle during the clamping of the tube. Another area of stress concentration is located where the lower portion of the side end wall inside the trunnion joins inside the lower end wall. Where the upper surface inside the trunnion meets the vertical portion of the side wall of the trunnion because of the need to maintain a uniform diameter at the projecting wheel axis,
No radius or curve or fillet can be provided.

The material of the tubing is usually I. V.
Plastic polyvinyl chloride of the kind used in the set. However, other medical grade plastic tubes can also be used. Such tubes typically have an inner diameter of about 2.3 to 3.0 mm and a diameter of 3.5 mm.
An outer diameter of from 4.5 mm to about 68 and usually 80
Shore hardness D below. Tubes of the type described may also be used with the clamps of the present invention. Groove 18 varies in cross-section along its length to change the cross-sectional area of the tube through which liquid flows.

In this illustration of a parallel acting clamp, the wheel functions to completely block the side wall of the tube for the reasons mentioned above, and the groove with a changeable cross-section defines the opening in the tube. The function of adjusting the flow rate of the liquid is changed. In the shape shown, the region of flow control extends approximately from region 22 to region 23. The lower surface includes a raised vertical element 25 at the distal end of the clamp, which acts as a lock to ensure complete interruption even in situations where the interruption area is just upstream of element 25. In fact, no flow occurs when the roller is positioned in the region of the end of the groove and before the bump. In this configuration, the movement of the wheel along its path is in a nearly, but not necessarily strict, parallel relationship over the area of flow control. This is because, as shown, the axle groove on the outer circumference is provided in a substantially or strictly parallel relationship with the surface 17 in the region of flow control. The movement of the wheel above the element 25 is not parallel, but, as described above, the flow is not controlled in this area. Typically, the clearance between the bottom of the wheel and the surface 17 is the same as the tube 20 used with this clamp.
It is usually less than twice the nominal wall thickness and does not exceed this. Because different sized tubes may be used, the clearance between the surface 17 and the bottom of the wheel in the flow control area may be different for each different clamp using different sized tubes to maintain full clamping on both sides of the tube. Can be changed to Although not shown, depending on the clamp structure, the tube may be completely closed by tightening the tube on only one side thereof. This is because in such a design the flow lumen is biased to one side. Also, as shown, a tube holder structure 26 is provided at the larger end of the housing, remote from the vertical element 25.

As can be seen from FIG. 2, the housing has a substantially uniform cross section, the cross section being about 0.3 to 0.6 times the outer diameter of the tube, typically 1.2 mm. From 1.7
mm and the length of the housing is from 20 mm to about 5
It is between 5 mm. Uniform cross-section indicates that surface 17
The cross section of the bottom wall portion 17a forming the
It can be understood from the cross section of the wall portion 18a in the portion of FIG. The lower side walls 27 and 28 of the housing have essentially the same cross-sectional thickness as the bottom wall 17a and the groove wall 18a. Transition zone 2 between lower walls 27 and 28
9 is present, this being the part having the cross-section of the walls 27 and 28 and the cross-section of the trunnion walls 31 and 32 forming the side end walls of the trunnion groove in which the wheel axle 16 moves. Includes parts that have Transition area 2
9 is a trunnion wall and a wall 2 below the trunnion wall.
7 and 28 so as to better distribute the stress. This transition zone includes and forms the lower shoulders 31a and 31b of the groove, on which the wheel axle 16 runs. Above the shoulders 31a and 31b are the upper edges or walls 36 and 37 of the housing. These form the upper part of the trunnion groove. As seen in prior art clamps, these upper edges or walls have a cross-sectional thickness that is essentially equal to the cross-sectional thickness of the side walls 27 and 28. Thus, the top walls 36 and 37, the lower side walls 27 and 28, the trunnion walls 31 and 32, the bottom wall 17a, and the groove 18a all have basically the same cross-sectional dimensions.

As can be seen from FIG. 2, the side end walls 31 and 32 of the trunnion are actually part of the side wall and have a shorter vertical length than the entire side wall. However, these side walls 31 and 32 are basically parallel to the lower side walls 27 and 28. However, this side end wall of the trunnion is substantially parallel to and spaced outside of the lower side walls 27 and 28 to accommodate the wheel axles. The axle of the wheel is located inside the side end walls 31 and 32.

As can be further understood from FIG. 2, the side end wall 3
1 and 32 and the underside of the upper walls 36 and 37 forming the trunnion upper wall are connected to the side end walls 3
1 and 32 and trunnion lower walls 31a and 32a
As well as the junction between each of these, is essentially an acute angle, for example a right angle. These acute angles, shown as right angles between the inside of the trunnion groove side end wall and the top and bottom,
It forms areas of stress concentration and usually cannot be curved or bowed to reduce the stresses that are likely to be present at these joints. This is because the wheel axle has a cylindrical shape and must move in a truly straight line along the axial direction of the clamp body. The use of a tapered or varying cross-section wheel axle is not practical. Because the tapered wheel axle substantially follows the fillet or round contour at the inner corner between the trunnion upper guide and trunnion end wall and the trunnion end wall immediately above the trunnion lower guide and trunnion lower guide. This is because the required maximum contact cannot be easily achieved. However, in the case of transition areas 29 located outside the side and lower end walls, transition areas may be provided to reduce stress concentrations, as shown. This is because it does not interfere with the operation of the clamp and can relieve stress in areas where stress concentrations would normally have been relatively high.

Walls that are tensioned or deflected and have abrupt changes in corners or directions have areas of stress concentration in the corners that are exposed to greater stress than adjacent parts. This leads to structural defects. Where the use of rounds, bends or fillets is impractical, a thicker wall is utilized at the junction or intersection of the walls to provide a stronger area. However, such measures are avoided as much as possible, since the weight of the clamp body also increases in that case.

Referring to FIG. 3, a preferred shape of the roller clamp of the present invention is shown. Again, this is shown in the form of a parallel-acting clamp having the components, housings, V-grooves, wheels, tubes, etc. already described, but for purposes of explanation, only the housing 50 will be discussed. The cross section of the housing of the clamp can be divided into three sections, each of which is primarily due to the ease of adjustment and the grip of the tube, by taking advantage of the dimensional ratios shown and the ranges and various relationships described. It meets the specific requirements of the invention in order to reduce weight while maintaining good performance.

The upper section is above the upper edges or walls 51 and 52, ie, above the trunnion shoulders 53 and 54, above the trunnion upper walls 51a and 52a, and above the walls 61 and 62. Has a certain part. The upper walls 51 and 52 include sides 51b and 52b that extend slightly below the lower surfaces of the trunnion upper walls 51a and 52a to form part of the upper wall and upper section. The upper section must be able to withstand local indentations, flexing loads (arching) and is imposed by the clamping of the tube and by the wheel axle, whose position changes over the length of the housing. It must be able to withstand outward rotation. Thus, the top wall has a cross-section that is at least 20 percent thicker than the side walls. During the clamp tightening operation, the trunnion of the wheel
It compresses the lower surface 51a and 52a of the upper edge or wall. These lower surfaces must be able to withstand the penetration of the wheel axle or trunnion imposed by the wheel axle as a result of the clamping operation and having a relatively small radius of curvature. This local penetration typically takes the form of a local indentation due to the wheel axis. A less pronounced requirement is that during molding most of the shaft length of the part, or ideally throughout its length,
A flow path for injection must be provided for flowing the molten plastic, without being exposed to a large contact area that causes cooling and if it is too wide, solidification will occur too quickly. Lateral flow, forming the side walls 57 and 58, is also required. In addition, the upper edge 5
The cross sections of 1 and 52, as shown, are substantially circular in cross section.

The second section basically consists of the lower side wall 5
7 and 58, and the groove walls extending below the shoulders 53 and 54 forming the horizontally arranged bottom wall of the trunnion groove and the lower sides 51b and 52b of the upper walls 51 and 52 or A wall section including upper wheel axle guide wall sections 61 and 62. The transition area is the portion of this side area between the bottom side walls 57 and 58 and the trunnion end walls 61 and 62, which is a curved transition area as described and described above. 29 corresponds. The transition area according to the invention is located in the outer part of the housing, as shown, and gradually increases in thickness from just inside the outer surfaces of the side end walls 61, 62, so that the side end wall and its adjacent Lower side wall 5
At the intersection with 7 and 58, the thickness reaches a maximum, and gradually decreases toward the cross section of the lower side wall portions 57 and 58.

It should be understood that this also applies to the left side portion, as shown by the dotted line on the right side of FIG. 3 for purposes of illustration, but below the trunnion lower portion 53 of the side wall portion 61. Section 61 a has substantially the same cross-sectional thickness as side wall 61. The section 57a of the lower side wall 57 is
It is joined to and integrated with section 61a, but section 57a
Has substantially the same cross-sectional thickness as the side wall 57. According to the invention, the outer fillet or radius 29 extends the length of the trunnion groove, and is relatively small since the outer diameter of this fillet preferably does not exceed twice the thickness of the lower wall 57. Has only weight. This is in contrast to some prior art roller clamps, which have no roundness and a square transition area.

This side section must have sufficient strength to properly withstand the tensile forces generated in the clamp housing as a result of the clamping action of the clamp applied to it during use. The side sections are also vertically oriented so that the injection molded plastic can properly fill the side section portions of the housing without prematurely cooling and solidifying before the area is filled. To flow through a distance, it must have a smaller but sufficient flow cross section. Depending on the location of the "gate" that initially feeds the molten plastic into the cavity, this side may also need to have a flow cross-section to fill adjacent areas that are not addressed by its corresponding gate.

Here, the trunnion-side end walls 61 and 6
Note that the surface area of 2 is smaller than the surface area of the bottom lower side walls 57 and 58. By making the cross-sectional thickness of the trunnion side end wall smaller than the cross-section of the lower side wall, it is possible to reduce the weight of the entire clamp. Conversely, it is also possible for the cross section of the lower side wall to be thinner than the cross section of the trunnion end wall.

In accordance with the present invention, the cross-sectional thickness of the trunnion end wall is substantially equal to the lower side wall, and if the other dimensional relationships described herein are also used, the lower side wall It is preferably between 0.8 and 1.2 times the cross-sectional thickness of the wall. In one preferred form of the invention, the cross-section of the trunnion end walls 61 and 62 is the same as the cross-section of the lower side walls 57 and 58, if other dimensional relationships described herein are also used. Substantially the same. Except for the addition of two stress reducing materials (transition 29),
The wall thickness of the trunnion's vertical side walls (61, 62) and the wall thickness of the lower wall (57, 58) should have equal thickness to achieve minimum weight. . Because each of them carries the same tensile load. The cross-sectional thickness of the upper wall is preferably between 1.3 and 4.0 times the cross-sectional thickness of the side wall.

The bottom section basically comprises a bottom wall 60,
And the wall formed by the clearance groove 65, but this area must be able to withstand the same flexural loads as the upper area. The bottom wall is thicker in cross-section than the side walls. In this case, the end of the bottom wall beyond the blocking position and the locking position is tapered slightly. This taper is located well beyond the flow control area,
Basically, it is located between the movement limit of the roller and the far end of the clamp body.

The flex load in the bottom section is similar to the flex load in the top section, except that the flex load applied to the bottom section is applied through the outer diameter of the wheel, which is applied through the double layers of soft plastic tubing. The need to withstand penetrating loads is greatly reduced.

Further, since the cross-sectional area of the bottom section has a cross width wider (left and right) than the total width in the left and right upper sections, even if the cross-sectional thickness of the bottom section is smaller,
The required cross-sectional area to withstand the flex load can be achieved.

Thus, in an ideal configuration, the upper wall is at least 30 percent thicker than the side walls, the trunnion end wall and the lower end wall have substantially the same cross-sectional thickness, and The bottom wall has a cross-section that is thicker than the cross-section of the lower and upper end walls, but thinner than the cross-section of the top wall.

Further loads and requirements must be met, but if the above requirements are properly met, they are usually (with reasonable margin of security)
It is filled.

As already mentioned, according to the present invention:
The area of the top area of the housing has a larger cross-sectional dimension than both the side area and the bottom area. The area of the side area has a smaller cross-sectional dimension than the area of the top area and the area of the bottom area. The area of the bottom section is thicker in cross section than the area of the side section, but is thinner in cross section than the area of the top section.
In a preferred configuration, the end walls 61 and 62 of the trunnion grooves forming part of the side sections are
And 58 have substantially the same cross section. Here, the wall 57
And 58 need not be of the same cross section, but the bottom wall 6
It should be understood that it must be thinner than the zero cross section.

[0088] These requirements can be met with the dimensions of the housing shown in various relations, approximately within the scope described below. That is: (1) The side wall thickness is 1.1 times to 2.times. The wall thickness of the undeformed (nominal) soft plastic tube.
(2) the thickness of the top wall is 2.5 to 4.5 times the wall thickness of the undeformed soft plastic tube; (3) the thickness of the bottom wall Is 0.4 to 1.0 times the thickness of the upper wall; (4) The thickness of the side wall is 0.3 to 0.8 times the thickness of the upper wall. (5) The clamp housing has a weight to length ratio of 0.4
8 g / cm or less, preferably 0.1 g / cm.
It has a clamp housing weight (gram) to length (centimeter) ratio of 48 to 0.2, optimally 0.3 to 0.4, and an inner diameter of 2.28 to 3.18 mm and an outer diameter of 3.
A stiffness that can be clamped to completely block PVC tubing having a Shore D hardness between 0 and 6 mm and between 65 and 90 and an uncompressed wall thickness between 0.5 and 1.0 mm. Having

With normalized parameters, where the weight-to-length ratio is divided by the specific gravity specific to the plastic, the above values for ABS are modified as follows: ABS weight-to-length General range: 0.48 to 0.2 gm / cm Preferred range: 0.3 to 0.4 gm / cm.

Weight to length ratio of all plastics; general range: 0.39-0.17 gm / cm; preferred range: 0.25-0.33 gm / cm.

(6) The thickness of the upper and lower side walls is, as mentioned above, 2 / th of the thickness of the walls in the upper wheel guide section in the area forming the flow control area of the housing. (7) the thickness of the upper and lower side walls is less than the thickness of the bottom wall; (8) the thickness of the upper and lower side walls is outside the wheel. (9) The thickness of the upper and lower side walls is 2.5 times the thickness of the tube wall (clamped) with the tube undeformed (10) the ratio of the thickness of the upper and lower side walls to the thickness of the upper wall is less than 0.7 over the length of the clamp housing where flow through the tube is controlled. (11) The upper wall has a thickness-to-width dimension in cross section,
(12) The bottom wall is 1.2 to 2.5 times the thickness of the uncompressed tube wall; (13) ) The width of the wheel is between 0.175 and 0.270 inches (corresponding to about 0.44 cm to about 0.69 cm).

[0092] The clamp housing may also have an upper wall wheel guide section whose cross section has a width to height ratio of less than 2.0.

From the above, it can be seen that the clamp housing encompassed by the present invention is characterized in that, in its uncontrolled area (behind the inlet section and the complete blockage), the thickness of the top, side and / or bottom walls It is evident that the clamp housing is reduced in comparison with the wall thickness of the corresponding part in the area where the tube can be clamped and flow control or blocking can be achieved.

From the above description, the area of the side sections represents a substantial part of the clamping structure, and therefore the cross-sectional dimensions of the areas of the side walls, for example walls 57 and 58, and trunnion walls 61 and 62. It is evident that the reduction of acts to reduce the weight of the clamp.
The cross-sectional dimensions of each of 57, 58 and 61, 62 need not be the same, but each must be smaller than the cross-sectional dimensions of bottom wall 60. In a preferred shape, each of 57, 58 and 61, 62 have the same cross-sectional dimensions as described above. According to the invention, the walls of the V-groove 65 may be smaller than the cross-sectional dimensions of the bottom wall 60 and smaller than the cross-sectional dimensions of the region of the upper section, in one preferred form they are Are smaller than the cross section of the bottom wall and have substantially the same cross-sectional dimensions as the walls 57 and 58.

Another aspect of the present invention is to produce a housing for a roller mold clamping clamp that can improve the quality of existing molds and can now be modified to include many of the desirable features of the present invention. The present invention can be carried out for a mold to be manufactured. The method described is applicable to either inclined roller clamps or parallel actuation clamps.

A cross section of a typical prior art clamp housing is shown in FIG. FIG. 3 shows a preferred embodiment within the scope described for the present invention. By comparing the structure of FIG. 2 with the structure of FIG. 3, in the structure of the present invention, the cross-section of the upper wheel guide surfaces (51, 52) is increased, and the lower clamping surface 60 is essentially unchanged or Slightly thinner, lower side wall (57,
Note that the thickness of 58) and the upper part of the upper end walls (61, 62) are greatly reduced and the cross section of the upper wall is the largest. These are as described above. FIG. 5 is a diagram for facilitating comparison.

The lower clamping surface (the wall adjacent to the V-shaped relief groove) can and should be thinner than the upper (upper wall). This is because its width is wider than the width of the upper wheel axle guide surface. Approximately equal flexing forces are applied to both the upper and lower surfaces. Resistance to deflection, if other dimensions are similar,
Nominally proportional to the cross-sectional area. For this reason, a thinner section is preferred for the bottom clamping surface for an averaged structural design.

[0098] The upper wheel guide surface is narrower than the lower surface because of the opening that allows the wheel to move.
The upper wheel guide should be increased in thickness and cross-section to ensure adequate resistance to deflection, resistance to outward rotation, and resistance to indentation by the wheel axle.

The thickness of the side wall cross section is greatly reduced by utilizing thinner walls. This is because the primary load on the side walls during use of the clamp is tension. ABS, polystyrene, and other commonly used thermoplastics such as SAN, rigid acetal, and nylon have relatively high tensile strength but relatively low elongation. Thus, significant savings in weight are achieved by properly designing for the application.

In production, almost all drip set roller clamp designs are intended for injection molding. Their inner and outer surfaces are tapered (with a draft) to facilitate removal from the mold and can usually be made with a simple two-plate mold or the like. For a parallel acting clamp, this draft is
This results in a small angle above what is sometimes called the clamping surface, but this small angle (eg in the range of 1/2 degree) plays no role in controlling the flow as already described. Absent. The intended function, ie
Ease of use, ease of adjustment, rigid tube gripping, etc. are all determined by the mold core design. It is this core that forms the structure and dimensions of the interior of the housing. The dimensions, shape, dimensional tolerances, etc. of the core determine the clamping performance of the part to be molded. Therefore,
For almost all roller clamps, the function of the designed part appears to be centered on the core, and the shape, dimensions, etc. of the cavity are typically
45 to 0.060 inch (about 0.11 cm to about 0.15 inch)
It appears that it has been derived by simply specifying a uniform wall thickness in the range (equivalent to cm).

On the other hand, according to the present invention, the important factors involved in the improvement relate almost entirely to the cavity design and have little to do with the core design. To convert an existing mold, the mating surfaces of the halves of the cavity are slightly ground and then reassembled, as already described and further described. The cavity is also slightly offset with respect to the core. The core remains essentially unchanged, but its gate is
The positioning is repositioned so that the injected plastic can now be fed into the now thicker wheel guide surface.

The typical housing cavity in the mold is constructed in a clamshell fashion, and often the two halves 70 and 75 are nearly or exactly symmetric. See FIG. As is known, a mold core is also used, which is located within the cavity 76 during the molding operation. Prior art mold design used to produce one of the prior art clamps to produce a modified mold used to produce an improved clamp according to the present invention To change is required the following two relatively simple steps.

1. The two mating halves of the cavity can be manufactured to produce a new housing wall thickness.
Only a relatively small amount, ie 40 of the original wall thickness
% To about 80%. In FIG. 4B, this is shown as scraping surfaces 70A, 70B, 75A and 75B. If the wall thickness of the part is already typically slightly tapered (slightly thinner at the smaller end of the housing and typically slightly thicker at the larger end of the housing) ), The tapered shape should remain. here,
A typical draft would have a wall thickness of several thousandths of an inch per inch (about 2.54 cm per 2.54 cm).
m (corresponding to several thousandths of m). Draft is used to facilitate removal of the part from the mold. This slight taper can usually be maintained by removing (scraping) material by a uniform depth along the entire contact surface of the cavity half.

2. With the two halves of the cavity separated from each other as shown in FIG. 4B, a small amount of material is removed from the part of the molding surface that forms the outer part of the wheel guide on the housing to be molded. be able to. FIG.
In (B), these planes are shown at 70C and 75C. Since this is done only in this special area, no changes are made to the critical dimensions of the part to be molded, such as the definitive shape formed by the molding core.

The effect of moving the halves of the cavity closer to each other by an amount equal to 25 to 60 percent of the thickness of the side wall of the originally molded part is thus obtained. This vertical movement of the core is typically less than 20% of the original upper wall thickness.
It is in the range of percent to 70 percent.

These two steps are relatively simple to perform and can be performed quickly and at low cost. According to this method, there is almost no need to modify the normally expensive core part of the mold,
Only relatively small changes need to be made to the originally low cost cavity. All this is in sharp contrast to the much higher cost of building a new mold with a large number of cavities.

As mentioned above, one of the potential problems with prior art roller clamps is that they "pop out"
t) ". Referring to FIG. 6, a partial view of a clamp housing 100 for a parallel acting clamp is shown. It includes a left section 100a and a right section 100b for comparison purposes. As described above, the housing includes an upper wall or rails 102a and 102b;
Side wall 1 including side walls 104a and 104b.
04a and 104b are side wall portions 104e and 104
lower wall sections 104c and 104d located below f
And the side wall portions 104e and 104f form a trunnion that houses the axle of a wheel (not shown). Between the side walls 104a and 104b and the upper wall 102a
And below the bottom wall 105b
Which has a V-groove 107 therein as described above. Further in part, the shape of the tube holder 109 is shown. It is the same in function and location as 26, but basically consists of curved fingers 109a and 109b opening at both ends for passage of the tube.

When the tube is assembled in the housing, it is positioned on the bottom wall and the axles of the rollers are housed in trunnions 104e and 104f. Laura,
The trunnion is biased downward by an axle that compresses the upper walls 110a and 110b. Thus, it can be seen that the forces acting on the bottom wall 105 are not aligned with the upward forces on the trunnion upper walls 110a and 110b, resulting in the rotational movement indicated by arrows 115a and 115b. This rotational movement can cause the axle to fly out of the trunnion if the upper wall or rail cannot withstand this force. A strong top rail would withstand this pop-out, but such resistance depends on the cross-sectional thickness of the top rail and the modulus of the material used for the housing (modulu
s). The use of side walls that are thinner than the top wall also leads to the possibility that the adjustment of the wheel can be made easier while the wheel grips the tube tightly due to the relatively strong top wall. .

The simplified model shows that the warpage due to rotation is proportional to the cube of the thickness of the upper wall.
Thus, a slight increase in the thickness of the upper wall or rail can be expected to have a significant effect. Furthermore, since the flow through the orifice of a clamped tube is proportional to the square or the third power of the hydraulic radius, the change in clamping clearance as a result of the warpage is magnified to the fifth power when reflected in the new flow. obtain.

As can be seen from FIG. 6, the structure 100 on the left side
a includes a transition zone 125 between the lower portion 104c of the side wall 104a and the lower wall 125a of the trunnion. According to the invention, the side walls are connected to this transition area 12.
Except for 5, it has a reasonably uniform cross-sectional thickness. As shown, the transition area 125 does not exceed substantially 150% of the cross-section of the side wall, excluding the transition area, from any one point on the inner surface 128 to the nearest point on the outer surface 129. Has a width.

The corner 130 formed between the inner surface of the lower side wall 104c and the lower wall 125a of the inner surface is
Note that this represents the point of stress concentration. Such stress concentration points can be tolerated if the transition area is dimensioned as described, but the right wall 100b
It is also possible to eliminate this stress concentration point as shown in FIG. In this case, the transition area 130 has essentially the same cross-sectional thickness as the adjacent section of the side wall. That is, the cross section of the transition zone, when measured in the same manner as described above, is less than 150% of the cross section of the adjacent side wall, and preferably has the same dimensions as the side wall.

As another cost comparison, the cost of manufacturing a newly modified part may be compared to the cost of the original part. For example, a 30% weight saving typically results in a savings of as much as 20% of the overall production cost. This is because the raw material cost accounts for a large part of the overall production cost. This new design
Significant additional savings in production costs will also be realized, as they should be performed in a faster production cycle. This is because the wall portion has a thinner portion, and the thickened part is subjected to two-dimensional cooling instead of one-dimensional cooling, so that the time required for cooling the part is reduced. .

The following data compares the clamp of the present invention with commercially available clamps. Commercially available clamps are indicated by the name of the company that supplies them.

[0114]

[Table 1]

These data show a significant difference in weight to length ratio for some clamps, and that for the clamps with the lowest weight to length ratios except for the clamps of the present invention. It can be seen that the weight to length ratio of the clamp of the present invention is approximately twice. The clamp of the present invention also has a length-to-weight ratio much lower than the ratio of the Clinico clamp (0.594 grams / centimeter) and is made of a material of apparently lower density. I have.

All of the advantages of the new design will be retained if the gate is properly positioned. One logical location would be a location (edge gate) for injecting plastic symmetrically into the cavity at one end of the wheel axle guide surface of the housing. In this position, the path of the injected plastic flow has a shape that is close to ideal, ie it is not too small and has a substantially circular cross section. This flow tunnel can then "" feed "the thinner side walls and, if necessary, the rest of the housing cavity. Another location for the gate would be where plastic is fed to one end of the bottom clamping surface of the housing (an edge gate could also be considered). Again,
The cross section of the flow is wide and allows very good access to the thin side walls. To ensure the symmetrical nature of the part, usually two gates are used on opposite sides of the cavity, or one larger gate is centrally located. This center position is typically the center of the bottom clamp surface.

In essence, to improve at low cost,
Changes in the cavity, such as scraping the contact surface of the two halves of the cavity or slightly increasing the wheel axle surface, must be relatively modest. In addition, if the core is moved slightly relative to the cavity, this may result in a thicker top wall and a lower bottom wall within the range of 20% to 70% of the original top wall thickness. It is moved in such a direction as to make it thinner. The economic benefits that can be drawn from the method of changing the mold are compared to building a new mold to reflect the improved design.
Relatively large. This is because the companies that will directly benefit already have a large amount of manufacturing dies and a large market share. Modification of those molds
It can be done at very low cost, and
The downtime required for the conversion is also very short.

It is to be understood that this invention is not limited to the detailed description set forth herein, which details preferred forms of the invention. Such modifications will be apparent to those skilled in the art based on the above detailed disclosure. However, such modifications based on this disclosure should not be taken to depart from the spirit and scope of the present invention as set forth in the following claims.

[Brief description of the drawings]

FIG. 1 is a perspective view of a typical prior art clamp.

FIG. 2 is a sectional view showing the current shape of a clamping clamp used in the prior art.

FIG. 3 is a sectional view of a clamp housing according to the present invention.

FIG. 4A is a view showing a prior art mold,
(B) is a diagram showing a mold according to the present invention, similar to (A).

FIG. 5 is a diagram for comparing and examining one deformed shape (left side) of a new part (a conventional cross section is shown on the right side for comparison) to explain the effect thereof.

FIG. 6 is an enlarged view of a preferred shape (right side) of the transition area according to the present invention compared to another shape (left side) of the transition area according to the present invention.

[Explanation of symbols]

29 transition area, 50 housing, 51, 52 top edge or wall, 53, 54 trunnion shoulder, 57,
58 side wall part, 60 bottom wall part, 61, 62 trunnion side end wall part, 65 relief groove, 70, 75 half body, 76
cavity.

Claims (41)

[Claims] 1. I. V. A plastic roller-type clamping clamp assembly for use in a set, comprising: an upper and lower side wall; a top wall; a bottom wall between the side walls and including a bottom surface; A plastic injection molded housing having a wheel guide section and a wheel guide provided therein, the upper wheel guide section having an upper wheel guide surface and a lower wheel guide surface, and further comprising the upper side wall portion And a wheel guide-side end wall extending below the upper wall toward the lower side wall, and a wheel shaft mounted to move substantially along the axial direction of the housing. A roller wheel, wherein the wheel axle is housed in the wheel guide, wherein the wheel is in front of a bottom surface of the housing. Sized to have a space for clamping the tube between the facing sections of the wheel and further housed in the housing and within the space,
A deformable plastic tube having a portion positioned between the bottom surface and the wheel, wherein the bottom wall has a greater cross-sectional thickness than the side wall; A plastic roller clamping clamp assembly, wherein: has a lower cross-sectional thickness than the top wall; and the upper wall has a higher cross-sectional thickness than the bottom wall. 2. The upper and lower side wall portions have a smaller cross-sectional thickness than the upper wall portion, and the upper side wall portion is 0.8 times as large as the lower side wall portion. 2. The plastic roller clamping clamp assembly of claim 1 having a 1.2 times cross-sectional thickness. 3. The plastic roller clamping clamp assembly of claim 2, wherein each of said upper and lower side walls has a smaller cross-sectional thickness than said bottom wall. 4. The plastic roller clamping clamp assembly of claim 2, wherein each of said upper and lower side walls has substantially the same cross-sectional thickness. 5. Each of said upper side walls forms a side end wall of said upper wheel guide section, said side end wall being joined to said lower side wall, and said lower side wall being The section and the upper side wall have a cross-sectional thickness smaller than the cross-sectional thickness of the upper wall, and each of the lower side walls and each of the upper side walls of the outer portion of the housing. A transition area extending at least in the axial length of said upper wheel guide section, said transition area having an inner surface and an outer surface, said transition region being on an inner surface to an outer surface. 2. The plastic roller clamping clamp assembly of claim 1, wherein the cross-sectional thickness measured to the nearest point is less than 150% of the side wall thickness outside of the transition zone. . 6. Each of said upper side walls forms a side end wall of said upper wheel guide section, said side end wall being joined to said lower side wall, and an outer part of said housing. At the intersection of each of the lower side walls and each of the upper side walls, the transition area has a cross-sectional thickness that gradually increases from the upper side wall to a maximum thickness. A curved surface that increases and gradually decreases from the maximum thickness to a cross section of the lower side, wherein a cross section of the upper side wall excluding the transition area is a lower side excluding the transition area. The cross-section of the lower wall is 0.8 to 1.2 times, and the upper wall is 1.3 to 4.0 times the cross-sectional thickness of the lower side wall. The plastic roller mold clamping assembly as described. 7. The plastic roller clamp of claim 6, wherein said clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 8. Each of said upper side walls forms a side end wall of said upper wheel guide section, said side end wall being joined to said lower side wall, and an outer part of said housing. An intersection of each of the lower side walls and each of the upper side walls includes a transition area, and the transition area has a sectional thickness gradually increasing from the upper side wall to reach a maximum. And a curved surface that gradually reduces from the maximum to the cross-section of the lower side, wherein the bottom wall has a cross-sectional thickness at least substantially equal to the cross-sectional thickness of the upper side wall. The cross-sectional thickness of the upper wall portion is 1.3 to 4.0, which is the cross-sectional thickness of one of the upper side wall portion and the lower side wall portion.
The plastic roller clamping clamp assembly of claim 1, wherein the ratio is greater than zero. 9. The plastic roller mold clamp of claim 1, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 10. When the housing is made of ABS,
A weight-to-length ratio of 0.2-0.48 grams / centimeter, or a normalized weight-to-length ratio of 0.17-0.39, and an inner diameter of 2.18 mm to 3.18 mm Having a strength capable of completely blocking a polyvinyl chloride pipe having an outer diameter of 3.0 mm to 6.0 mm and having a Shore D hardness in the range of 65 to 90 by tightening; The plastic roller type clamping clamp assembly of claim 1. 11. The plastic roller mold clamp of claim 3, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 12. The plastic wall according to claim 3, wherein the side wall is 1.1 to 2.3 times the thickness of the wall of the plastic tube.
A plastic roller mold clamping assembly according to any one of the preceding claims. 13. The plastic tube according to claim 6, wherein the side wall is 1.1 to 2.3 times the thickness of the wall of the plastic tube.
A plastic roller mold clamping assembly according to any one of the preceding claims. 14. The plastic roller mold clamp of claim 1, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 15. The clamping clamp according to claim 1, wherein the clamping clamp includes a flow control area, wherein the cross section of the upper and lower side walls in the flow control area is less than two thirds the thickness of the upper wall. Plastic roller mold clamping assembly. 16. The plastic roller clamping clamp assembly of claim 1, wherein a thickness of each of said side walls is less than a thickness of said bottom wall. 17. The housing includes an upper wheel axle guide section, wherein the thickness of the side wall is greater than 2/3 of the thickness of one of the upper wheel axle guide section and the bottom wall. 17. The plastic roller clamping clamp assembly of claim 16, which is thin. 18. The plastic roller clamp of claim 10, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 19. The clamp assembly has a range of wheel travel over which flow can be adjusted through the tube, and the wheel rollers adjust flow through the tube therein. Moving in a parallel relationship to the bottom surface over the range of possible wheel travel, wherein the roller-type clamping clamp assembly changes the lumen formed for use and thus changes the flow rate 2. The method of claim 1, further comprising the step of:
V. Plastic roller mold clamping clamp assembly for use in sets. 20. The clearance according to claim 1, wherein the clearance is less than twice the thickness of the undeformed wall of the tube.
I.9. V. Plastic roller mold clamping clamp assembly for use in sets. 21. The clamp having an uncontrolled area between an inlet section of the housing and a blocking position, wherein the thickness of the top, side and bottom walls controls the flow. The plastic roller clamping clamp assembly according to claim 1, wherein in a region where no flow occurs, the tube has a smaller thickness compared to a corresponding portion where the tube is clamped to achieve flow control or flow interruption. 22. The upper wall wheel guide section,
The plastic roller clamping clamp assembly of claim 1, having a cross-section whose width to height ratio is less than 2.0. 23. A plastic injection molded housing having spaced side walls, a top wall, and a bottom wall including a bottom surface; and each side wall below the top wall. A trunnion; and a roller wheel having a substantially cylindrical wheel axis mounted to move substantially along the axis of the housing, the wheel axis being contained in the trunnion; Sized to have space for clamping tubes between the bottom surface and the facing section of the wheel, further housed in the housing and within the space;
A deformable plastic tube including a portion positioned between the bottom surface and the wheel, the side wall having an upper side wall and a lower side wall with a transition area therebetween. And, the cross-sectional thickness of the side wall is thinner than the top wall and the bottom wall, the cross-sectional thickness of the top wall is thicker than the bottom wall, and the housing is made of ABS. 0.2-0.48
I. having a weight to length ratio in the range of grams / centimeter, or a normalized weight to length ratio between 0.17 and 0.39. V. Plastic roller mold clamping clamp assembly for use in sets. 24. The plastic roller mold clamp of claim 23, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 25. A spaced side wall, a top wall, a bottom wall including a bottom surface, and a space above the bottom wall for receiving an axle of a roller wheel. A plastic injection molded housing having a trunnion; and a roller wheel having a wheel axis mounted for movement substantially along the axis of the housing, the wheel axis being contained within and moving within the trunnion. The wheel is dimensioned to have a space for clamping a tube between a bottom surface of the housing and a facing section of the wheel, further housed in the housing and in the space; To
A deformable plastic tube including a portion positioned between the bottom surface and the wheel; the trunnion including a side end wall forming an upper side wall of the housing; A lower side wall below the upper side wall, and further including a transition area between the upper side wall and the lower side wall; a cross section of the upper wall; A ratio of a thickness to a cross-sectional thickness of the upper and lower side walls other than the transition area is in a range of 1.3 to 4.0, wherein the upper side wall is the lower side; I. having a cross-sectional thickness between 0.8 and 1.2 times the wall thickness of the I.P. V. Plastic roller mold clamping assembly for use in sets. 26. The plastic roller mold clamp of claim 25, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 27. A plastic injection molded housing having spaced side walls, a top wall, a bottom wall including a bottom surface, an upper wheel guide section and a wheel guide provided therein. Said upper wheel guide section having an upper wheel guide section and further including a roller wheel having a wheel axis mounted to move substantially along the axis of said housing, said wheel axis being contained within said wheel guide. The wheel is dimensioned to have a space for clamping a tube between a bottom surface of the housing and a facing section of the wheel, and is further housed within the housing and within the space. To
A deformable plastic tube having a portion positioned between the bottom surface and the wheel, the side wall comprising an upper side wall and a lower side wall, and an upper side wall; A transition area positioned between the lower side wall and on the exterior of the housing, wherein the ratio of the cross-sectional thickness of the upper wall to the cross-sectional thickness of the side wall is 1.3.
From 4.0 to 4.0, wherein each of the upper and lower side walls has substantially the same cross-sectional thickness except at the transition area, and wherein the upper and lower side walls are the upper wall portions. I. and a lower cross-sectional thickness than said bottom wall. V. Plastic roller mold clamping clamp assembly for use in sets. 28. The plastic roller mold clamp of claim 27, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 29. A plastic injection molded housing having spaced side walls, a top wall, a bottom wall including a bottom surface, and an upper wheel guide section and a wheel guide provided therein. The upper wheel guide section has an upper wheel guide section and further includes a roller wheel having a wheel axis mounted to move substantially along the axis of the housing, the wheel axis being contained within the wheel guide. The wheel is dimensioned to have a space for clamping a tube between a bottom surface of the housing and an opposing section of the wheel, and is further housed within the housing; Within
A deformable plastic tube having a portion positioned between the bottom surface and the wheel, the side wall comprising an upper side wall and a lower side wall, and an upper side wall; A transition area between the lower wall and the lower wall, the transition area being located on the exterior of the housing, wherein a ratio of a cross-sectional thickness of the upper wall to a cross-sectional thickness of the side wall is 1.3.
From 4.0 to 4.0, wherein the cross-sectional thickness of the upper side wall other than the transition area is 0.8 times the cross-sectional thickness of the lower side wall other than the transition area. The top wall is thicker than the thickness of each of the upper and lower side walls except at the transition area and greater than the thickness of the bottom wall. Wherein the housing has a normalized weight to length ratio in the range of 0.2 to 0.48 grams / centimeter.
V. Plastic roller mold clamping clamp assembly for use in sets. 30. The plastic roller mold clamp of claim 29, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 31. A plastic injection molded housing having spaced side walls, a top wall, a bottom wall including a bottom surface, an upper wheel guide section and a wheel guide provided therein. The upper wheel guide section has an upper wheel guide section; the wheel guide has a side end wall of the upper wheel guide section; and the side end wall extends from the bottom wall section to the upper wheel guide section. A roller wheel having a lower side wall extending toward and further having a wheel axis mounted for movement substantially along the axis of the housing, wherein the wheel axis is housed within the wheel guide; Provides space for clamping tubes between the bottom surface of the housing and the facing section of the wheel. Have dimensions such that, accommodated further into the housing and into the space,
A deformable plastic tube having a portion positioned between the bottom surface and the wheel, wherein a ratio of a cross-sectional thickness of the top wall to a cross-sectional thickness of the upper and lower side walls is from 1.3. 4.0, wherein each of the upper and lower side walls is 0.8 to 2.5 times the wall thickness of the tube under uncompressed conditions; And a cross-sectional thickness of the lower side wall portion is smaller than a cross-section of each of the upper wall portion and the bottom wall portion. The housing is thicker than the cross-sectional thickness of the wall portion.
Gram / centimeter weight to length ratio, or 0.
Having a normalized weight to length ratio of 17-0.39,
I. V. Plastic roller mold clamping clamp assembly for use in sets. 32. The housing includes a small end having a central portion therebetween and a larger open end, wherein the upper wall is at least one of the small end and the open end. 32. The roller-type clamping assembly of claim 31, wherein, on the one hand, the thickness of the central portion of the housing is less than a thickness of an upper wall. 33. The plastic roller mold clamp of claim 31, wherein the clamp is a parallel acting clamp, further comprising means for changing the lumen formed for use and thus changing the flow rate. Clamp assembly. 34. The I.I. of claim 23, wherein said housing has a normalized weight to length ratio in the range of 0.3 to 0.4 grams / centimeter. V. Plastic roller mold clamping clamp assembly for use in sets. 35. When the housing is made of ABS,
Claims having a weight to length ratio in the range of 0.3 to 0.4 grams / centimeter, or a normalized weight to length ratio of 0.25 to 0.33 grams / centimeter. 2
I.9. V. Plastic roller mold clamping clamp assembly for use in sets. 36. When the housing is made of ABS,
Claims having a weight to length ratio in the range of 0.3 to 0.4 grams / centimeter, or a normalized weight to length ratio of 0.25 to 0.33 grams / centimeter. 3
I.1. V. Plastic roller mold clamping clamp assembly for use in sets. 37. The ratio of the thickness of the upper wall to the thickness of the uncompressed wall of the tube is 2.5 to 4.5.
Wherein the ratio of the thickness of the side wall to the thickness of the uncompressed wall of the tube is in the range of 1.1 to 2.3, and the thickness of the bottom wall to the tube. 2. The plastic roller clamping clamp assembly of claim 1 wherein the ratio of the uncompressed wall thickness of the unstrained wall ranges from 1.2 to 2.5. 38. Each of the side walls includes a bottom wall and a pair of spaced side walls extending upwardly from the bottom wall to form a generally U-shaped cross section. The portion has an upper side wall portion and a lower side wall portion, wherein the lower side wall portion defines an inner cavity for receiving a hollow tube therein, and wherein the upper side wall portion comprises the lower side wall portion. Partially defining an elongate groove extending substantially along the length of each of the upper side wall portions, substantially parallel to and laterally spaced apart from the side wall portions; Further, the housing includes a pair of upper rails extending inwardly from the upper side wall portion to form a top wall, the rails forming a top surface of the groove, and opposing the bottom wall portion. A roller, wherein the roller is housed in the groove and the roller is housed in the housing. An axle extending outwardly for axially moving along the flow control area to control the flow of liquid through the tube, the axle compressing the side rails when compressing the tube; Wherein the upper rail has a predetermined thickness sufficient to withstand large warpage from the bottom wall of the rail when the roller compresses the tube, and wherein the side wall portion Has a reduced thickness such that the thickness of each upper rail is approximately 1.3 to 4.0 times the thickness of each side wall portion, so that the housing is The bottom wall and the top wall are formed to minimize the amount of plastic material in the housing while maintaining the effectiveness of the clamp to properly withstand the forces applied and to properly control the flow of liquid through the tube; Each of the parts It has a substantially uniform cross section along the length of these, I. V. Plastic roller mold clamping clamp assembly for use in sets. 39. A method of modifying a mold used to manufacture a plastic roller clamp housing, said mold being used to manufacture a roller clamp housing having an upper wall section. Things,
The method includes moving the core in one direction relative to the cavity so as to increase the thickness of the top wall of the molded housing, the movement comprising the thickness of the original top wall. The method ranges from 20 percent to 70 percent of the method. 40. A method for modifying a mold used to manufacture a plastic roller clamp housing, the mold being used to manufacture a roller clamp housing having an upper wall section. Things,
The method modifies the cavity of the mold so that its inner side walls are closer together, so that the part to be molded is better than that produced in a mold prior to such mold modification. A method comprising altering to have a thin side wall, wherein the magnitude of the movement ranges from 20 percent to 70 percent of the original wall thickness of the housing. 41. A low cost method of repairing a two cavity half and a core mold for manufacturing a housing for a plastic roller clamp, said housing comprising an upper wall section; Having spaced side walls having a bottom wall therebetween, the method comprising: moving the core in one direction relative to the cavity to thicken a top wall of the housing; Bringing the inner side walls of the cavity of the mold closer together and changing the part to be molded to have a thinner side wall than that produced before such a modification; Thus, a method wherein the method results in greatly reducing the weight of the housing while producing a housing structure having a top wall that is thicker than its side walls.