CN1167642A

CN1167642A - Improved roller clamps for intraverous administration sets and method of making same

Info

Publication number: CN1167642A
Application number: CN97111127.8A
Authority: CN
Inventors: K·阿德尔贝格
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-05-06
Filing date: 1997-05-06
Publication date: 1997-12-17
Anticipated expiration: 2017-05-06
Also published as: JP2006043481A; ITMI971040A0; IT1291305B1; JPH1033673A; CN1203909C; DE19718465A1; FR2748395B1; JP4478094B2; FR2751231B1; DE19718465B4; DE19718465C5; ITMI971040A1; FR2751231A1; FR2748395A1

Abstract

An improved injection molded plastic roller pinch clamp for IV sets includes a housing having side walls, a bottom wall, a top wall, a flow control region, a roller wheel and plastic tubing which is pinched between the roller wheel and the bottom wall. Methods for making the same and mold modifications to make the same are disclosed. The housing is formed by a mold which may be easily modified from a prior mold to provide a wall thickness which is less than two thirds of the thickness of the upper wheel guide section. Methods for modifying molds having two cavity halves are also discussed, including processing the cavity halves to bring them closer by an amount equal to 20 percent to 70 percent of the original molded part.

Description

Improved roller clamps for intraverous administration sets and manufacture method thereof

The present invention relates to a kind of intravenous drip (I.V.) device and use the roller hold down gag, be specifically related to a kind of improved roller clamps for intraverous administration sets, it has the distinct advantages that reduces manufacturing cost and Te Jia polarization.

The intravenous drip device is to be disposable apparatus from being repeatedly used to evolve at the forties to the fifties.Early developed a kind of technology that is used to produce and store fluid such as water, saline dilute solution, glucose and other nutritional solutions and the some drugs of the medical grade that is used for the human body infusion before this.These fluids are stored in the sealed glass container and adopt the sterilization medical rubber hose to instil.These rubber tubes and other instillation utensils are sterilized again usually and are reused.The control of fluid drip velocity is to regulate by the degree that compresses that changes on the rubber tube.For this application, various clamping devices had once been developed.

Along with the appearance of polrvinyl chloride (PVC) pipe of the increase of using, medical grade and the needs that reduce or eliminate serious patient/nosocomialtion, introduced disposable drop instillator.This has solved the cross infection problem, but has drawn a new problem: flow velocity changes in time, i.e. the desirable flow velocity time to time change of initial setting.Compress plastic tube exists creep or cold deformation when compacted problem, and this causes that flow velocity changes in time, this variation very big usually (be about 40 percent in first ten minutes and increase), and reduce flow velocity often.

Big once the description about about 1967 attempts to solve flow velocity first clamping device of variation issue (not being horizontal movement) in time, introduced a series of improved horizontal movement clamping devices in some years after this, and obtained significant improvement.The main direction of this clamping device newly developed was to be convenient to regulate the then normally easy to use and/or combination of time dependent adjustable flow velocity hardly after 1967 before 1967.

Another kind of improvement provides a kind of clamping device of clamping tube better, because if the clamping device chance is unclamped, can cause that then flow increases, and understands out of control under extreme case and threat to life.

Under the situation of typical products in mass production, manufacturing cost is Fundamentals normally.The factor that typically reduces cost that can provide and use has: (1) does part littler of economical with materials, and (2) adopt lower cost materials, and (3) make part be easy to assembling to reduce labour cost.

Injection mould is the most general method of producing clamping device.In view of economic pressures to the sustainable growth of a large amount of uses that reduce or reduce health care cost, infusion device and plastic resin cost, increased widely seeking a kind of interest of clip, this clamping device should be able to satisfy above-mentioned needs: (1) is easy to use, (2) reducing flow velocity changes in time, (3) clamping tube more firmly, and (4) can be with low-cost production, still can be lower than to take part is done forr a short time, increased and produce the die cavity number and/or adopt the obvious measure of low-cost resin and the cost that obtains.

As everyone knows, the roller clamping device that is used for the intravenous drip infusion device thinks to be attached to the intravenous drip device sometimes and general and intravenous drip device fit together after having used once, and mainly is designed to regulating by a fluid flow that is generally the flexible and deformable flexible plastic tube of the polrvinyl chloride that hangs down the extraction degree.Usually the clamping degree with pipe arrives desirable value with flow rate regulation, generally measures with the number that drips of per minute, and the latter represents that required fluid carries out the fixing speed of intravenous drip.These clamping devices also are used as opening/closing device, promptly allow to flow or stop to flow.This is not that clamping device is in case installing will and be closed mobile according to time accurate control flow velocity when needed fully.

The typical prior art clamping device is that applicant's existing patent is as follows: United States Patent (USP) 4047694,1977 years; 4013263,1977 years; 3685787,1972 years; 5014962,1991 years; 4725037,1988 years; And Re31584,1984; In this manual with reference to the disclosure of having quoted above-mentioned patent.

In general, the roller clamping device of intravenous drip infusion device has two kinds of fundamental types, a kind of is " inclined ramp " clamping device, and another kind is the device of advancing with being called the clamping device of " horizontal movement " or its roller and general alleged clamping surface almost parallel in this description.Under each situation, clamping device comprises all that basically one is equipped with the housing of a roller, and this roller is generally supported by housing with plastic tube, and this plastic tube is placed in the housing and locatees between the intravital bottom surface of shell or clamping plane and roller.

No matter the clamping device of any type, be " fully flowing " at an extreme position of roller, promptly with flowing that the abundant energy of flow masterpiece of intravenous drip device is not regulated.Generally then be no mobile one no flow locations in managing with the roller another location that abundant flow locations is separated mutually.This is a closed position normally.Also have another closed position in some clamping devices, the locked position that definitely prevents the roller motion that will describe below more suitably saying so does not have mobile in this position pipe.In the roller travel zone that fully may command of general existence flows between flow locations and the no flow locations, promptly so-called " control of flowing " zone.The ultimate range that the length of control area of flowing can be advanced less than roller at a direction of principal axis is especially under the situation that has a locked position.

Under the situation of inclined ramp, mobile control realizes by one " inclined ramp " principle, promptly the thumb by the operator makes roller climb up a slideway, thereby roller is reduced with gap between the relative surface of shell of stopping pipe, requiredly compress degree and thus flow velocity is controlled thereby produce.When roller forward the time, roller and the gap of stopping between the surface of shell of pipe reduce, in its extreme positions with the pipe contract fully.For the flow rate regulation of typical hold down gag, tube chamber quilt in very big central area fully flattens (the pipe radius of curvature is very big) herein, and forms a pair of tube chamber also thus to compressing the resistance that provides bigger in both sides, the minimum place of compacted pipe radius of curvature.Cold deformation in the plastic tube or creep have explained that the tube chamber that why newly forms can continue flattening and flow velocity is reduced after roller advances to and remain on the one reposition.

In a horizontal movement (dual-action) clamping device, reduce or preferably cancel creep or cold flow effect everywhere by the mobile control area that makes housing, one housing parts guide roller is to form a pipe gap, this pipe gap forms at least one at one or two outer rim place, is generally two tube chambers, is closed thereby compress fully.Because do not have or the less bottom surface that compresses or housing or roller in an earial drainage portion is arranged, so realize accurate flow speed control by the ratio that fully compresses closed portion and other parts of staying open that changes compacted pipe.The action of roller or advance needn't be accurately or even be parallel to the relative clamping surface of housing nearly.The criterion of parallel action clamping device is to have one to make the part of pipe fully compress the gap of closing between roller and housing, and contact is arranged or near the remainder of the surface of shell of pipe, pipe has one and allow and/or be easy to form a dozen earial drainage portions of beginning to speak in pipe.

In the horizontal movement clamping device, roller generally speaking compresses near the part of pipe and the pipe that utilizes earial drainage portion in the housing to produce required degree usually compresses or part is closed.When adopting " parallel " this term, be not meant how much parallel or roller is advanced in exactly parallel mode a kind of configurations on its whole travel range; The mobile span of control that this " parallel " action is only advanced at roller just needs.In fact, horizontal movement clamping device can and usually roller advance stop with pipe and clamped apparent surface between comprise a relative little angle, for example below will be discussed design as injection mould in the result of used " pattern draft ".Yet, opposite with the inclined ramp clamping device, because the gap deficient change between roller and the tube grip surface is with the mobile cross-sectional area of direct change, so this relatively little angle itself is not enough to also be unlikely major control and the change that influences flow velocity.Shell area is before the control of flowing and close the back or the no flow locations opposite with locked position also is this situation, clamp move in its structure, also can be nonparallel.The zone of control since these non-systems flow, almost parallel action so as described herein promptly has no truck with or is unnecessary.

Although a side buccal of wherein having only pipe is fully clamped the horizontal movement roller clip locking structure of closing by fully compressing one otherwise be about to the tube chamber that forms and cause creep and cold deformation, can be configured for changing a kind of improvement of the clamping device aspect of (flow and change in time) design, all can fully compress and close but more advanced design is buccal, both sides to compacted flexible plastic tube with respect to time of flow velocity.

The characteristics that horizontal movement (dual-action) roller clamping device is different from the inclined ramp clamping device are how to realize the control of flowing.Horizontal movement roller clamping device can be realized flow speed control by a side buccal is fully compressed to close, common then be on whole mobile span of control, the buccal, both sides of pipe all fully to be compressed to close, and fully compress according to the position change of roller in the control area of flowing and to close and do not compress the ratio of opening part.Obviously, be in the roller travel range of control effective range that flows, just need fully compress to close buccal, one or both sides rather than adjacent pipe part.Under the situation of inclined ramp, mobile control is to realize with the gap between the relative pressing surface by changing roller.Therefore clearly, even do not exist real parallelly in " horizontal movement clamping device ", and not parallel degree is not enough so that in fact influence the gap of flow velocity and make any amount and change.Close if in the control area of flowing, the buccal, one or both sides fully compressed in the travel range of roller, then especially like this.

A kind of buccal, one or both sides of supposing pipe fully compresses the Typical Disposition of closing provides a gap between idler wheel bottom and housing apparent surface, pipe is compressed facing to housing, the gap generally is not more than two times of wall thickness of compacted pipe, is two times less than pipe thickness in some cases.One turns round usually satisfactorily less than the gap of two times of pipe thicknesses closes to guarantee that the buccal, one or both sides fully compresses.In addition, it is also understood that this limited gap only need be present in mobile control area.In fact, the gap at the arrival end place of housing greatly then can be littler near the housing port of export, if any opened in one minute close locked position the time then especially true.

In " horizontal movement " clamping device, the gap between roller and the relative housing clamping surface can with or not with the roller position change, but this space change substantially control form the size of tube chamber.Be to realize controlling with the ratio of clamping part not in this case by changing the clamped wall part of closing.

In the inclined ramp clamping structure, when roller is advanced, the central part branch of compacted pipe is sagging and fully compress and close, but the gap between roller and the relative surface of shell: (1) will be even as big as allowing to form tube chamber, and normally at the place, buccal, one or both sides of pipe, and (2) will change to generation required tube chamber size and flow rate corresponding.

In a kind of not too general horizontal movement clamping device, earial drainage portion is the surface at roller.Total characteristics of this clamping device are that the cross section opened areas of pipe is advanced with roller and changed, and the quantity of opened areas is relevant with earial drainage portion structure.As is generally known earial drainage portion can have different shape can close a side or pipe bottom or some other positions of housing.Its function is that the motion according to roller changes mobile opened areas.

In fact the clamping device of all kinds all adopts a roller and a housing, when roller or roller position change and when it when producing required clamping degree, the axle of roller promptly is pressed on the guiding surface.

In clamping device involved in the present invention, following some specific (special) requirements and some important feature are arranged: the upper surface of (1) housing should be designed to resist the compression by roller shaft.(2) upper surface of housing should be designed to be subjected to one for example cause by the axle of a pinch rollers upward force the time can be counter-bending.(3) sidewall of housing should be designed to bear pulling force.(4) should be designed to can be counter-bending and turn round under the compression situation for the upper surface of housing, is that variable-width earial drainage action and is used for the special ideal position that is raised element and gives security.Be raised element as use, it have variation height, width and at interval.(5) housing should be made by mouldable plastics, should have one and be designed to be convenient to the cross section that mouldable plastics inject whole steel mold cavity.

The horizontal movement clamping device was introduced into market on 1975 with the commodity scale, and shell length was about 2 inches at that time.The shell length of competitive inclined ramp clamping device then is 1.4 inches.Because the performance of horizontal movement clamping device is better than inclined ramp clamping device, so occupied the main market share, to 1978, the Abbott Labs (another family is Baxter Traenol) of one of company that two families of the U.S. are maximum was occupying all market basically aspect the product that is used for the required clamping device of intravenous drip device.About 1986, Baxter company begins to adopt a kind of long clamping device that has patented.After this, other have introduced the clamping device that has 2 inches housings as companies such as Cutter (in fact more promptly beginning in early time), McGaw, IVAC and Borla, and have formed a kind of trend therefrom.

Use widely along with longer clamping device has improved manufacturing cost for most market, though many longer clamping devices do not provide the improvement performance of the horizontal movement clamping device that has patented.Under the situation of the horizontal movement clamping device of Abbott, the reason that function aspects is arranged for length, except providing time-independent flow velocity and for the more firm clamping of pipe, long roller amount of travel allows clamping degree and flow velocity are done thinner adjusting.

Therefore, with longer trend concerted effort in, market shows as little care significantly to introducing heavier clamping device, or gives lower priority for this increase of heavier clamping device manufacturing cost relatively thereafter.It is the summation of basic used clamping device quantity that this cost increase is expressed as with 1 year.

Occupy the occasion of a very big or major part at the plastic resin cost in manufacturing cost, because plastic resin portion accounts for 50 percent of production cost, the cost of producing roller clamping device and many other working of plasticss in recent years sharply increases.Then be that molding costs part is less relatively and cost of raw material part is relatively large and increasing at present.Therefore, if the redesign of spendable moulded parts equally can be utilized but significantly reduces used plastic resin in order to provide at least, then can save production cost greatly.

The clamping device of most of forms has a housing, and its wall thickness cross section is uniform basically.At first will focus in a few significant surfaces during the clamping device design, can determine design parameter, as: the housing pressing surface, the roller shaft guide surface, roller grooves etc. by the simple uniform wall thickness of specifying, are promptly finished design then.

Novel clamping device of the present invention not only provides required clamping form (the pipe sidewall fully clamps and closes etc.), but also bond strength (bending modulus etc.) and mould design (injection moulding of injection channel fully), and has the structure that can significantly reduce each clamping device material requested.

At present typical clamping device has the size of following scope:

(1) roller full diameter width be pipe name external diameter 1.3-1.8 doubly, and

(2) the housing wall thickness is not to be out of shape more than 2-3 times of flexible plastic tube wall thickness, and is generally more than 3 times, and

(3) even in the entire cross section wall thickness, at the flow adjustment place (control area of flowing), this cross section is all identical along the housing working length.

A tangible method that reduces pts wt is exactly to reduce the length of housing.Yet this is not desirable, because be for the ease of introducing roller so that assembly can be operated in the shell length of its big end parts usually.Remaining part is mainly used to provide a rational travel range progressively to compress pipe in any position along release portion or control part of housing for roller.

Reduce the overall width of clamping device housing cross section or highly be unpractiaca because as cook the flexible plastic tube that will be difficult to center on and compress a given diameter.

Present clamping device housing has a uniform wall thickness, and its scope is 0.3-0.5 a times of the folded tube outer diameter of this clamping device.

The minimized case length that a reality is arranged.For the pipe of external diameter Commonly Used Size in 31/4 to 41/2 millimeter scope, the minimum length of housing or is about 7 to 25 times of tube outer diameter in 23 to 55 millimeters scopes.The wall thickness of clamping device housing typically is 1.2 to 1.7 millimeters, or is about 0.2 to 0.5 times of tube outer diameter.The most important thing is that the clamping device housing is normally uniform on cross section.Do like this (wall thickness is even) obviously be because:

1. determine simple.

2. be one to be used for the traditional design parameter of injection molding.Uniform wall thickness is convenient to plastics are injected punching block.

3. the parameter that most of clamping devices design aspect the mechanically deform of expecting when being subjected to the stress relevant with tube grip for plastic casing seldom or is not considered.

Many parameters are depended in mechanically deform (strain), for a given plastic resin material such as an ABS (acrylonitrile butadiene styrene copolymer), then depend on the kind (stretch, crooked, compress, reverse etc.) of stress and stress.Good design should make the distortion minimum under load, or allows distortion but this distortion should be in elastic range by design, perhaps as exceed elastic range and then make the deflection that exceeds elastic range for minimum.

When the clamping device housing comes into operation promptly when compressing other parts assemblings of pipe and intravenous drip device with one, promptly produce the distortion of expection, its deflection depend in part on add stress kind (stretching, bending etc.).Owing to pass through the roller shaft applied pressure in itself and upper surface contact position, by the secondary component of partial compression, the main tension of the sidewall of clamping device housing, top margin or roof are then mainly by bending or deflection.When it is used to compress pipe the distortion of its housing or mechanically deform will be because:

1. mainly be the distortion or the bending of housing top margin or roof.

2. secondly be because the tension of housing sidewall.

3. on a less degree, be owing to act directly on the localized compressive force of the housing top edge that contacts by roller shaft.

4. be applied to the surface of shell bottom by the main circumference of the roller double wall thickness by compacted flexible plastic tube.

If refer now to the prior art patent of relevant clamping device, most of patents there is no description for sidewall than the roof of housing or diapire are thin.And accompanying drawings of the patent of some relevant roller clamping devices trend towards describing various layouts, then there is no instruction for the size of wall shown in why taking.For example, United States Patent (USP) 1411731; 1959074; 2595511; 3135259; As if 3189038 and 3289999 show uniform wall construction.United States Patent (USP) 3099429; 3215394; 3215395; 3297558 and 4340201 have comprised and can be used as the accompanying drawing that thin-wall construction explanation is shown.Wherein, be presented to United States Patent (USP) 3099429 worth special commentaries of Broman.

Broman shows a kind of clamping device and its clamping surface than thin sidewalls that have and looks thinner than sidewall.Yet for for the purpose of the present invention is consistent, as being discussed, in the Broman scheme, the roller shaft guiding surface of housing should be thicker than clamping surface, simultaneously also than side thickness.In the Broman scheme, the thickness of guiding surface is identical with thin sidewalls and much thinner than clamping surface.The consideration of not mentioned weight savings of Broman and intensity aspect (stretching, bending etc.), also not mentioned why wall thickness is as illustrated, and it seems that the section thickness of position only is random.

Therefore, one object of the present invention is to provide a kind of new clamping device structure, this structure will have and the better same performance characteristics of clamping device, for example the sort of the sort of clamping device that has similar outward appearance and be suitable for injection molding of indication in same inventor's the patent also will obtain lower production cost in this new invention.

Another object of the present invention is to provide a kind of clamping device that significantly reduces materials used.

Another purpose of the present invention is to provide a kind of improved clamping device that adopts short molded circulation time.

Under the situation of horizontal movement clamping device, another object of the present invention is to provide a kind of and flow velocity is reduced over time or minimized improved clamping device.

Further purpose of the present invention be to provide a kind of can be on compacted pipe the improved clamping device of firm grip.

Another purpose of the present invention is to provide a kind of uniqueness and not expensive method, and it is molded to realize above-mentioned purpose to be used to improve existing housing.

According to the present invention, improved roller clamping device by being provided for the intravenous drip device, more specifically a kind of improved roller clamping device that is used for the intravenous drip device of saying so is realized these and other purposes, this clamping device has minimizing manufacturing cost, the good relative less distinct advantages with physical dimension of positioning performance of spy, so that significantly reduce manufacturing cost when keeping premium properties.

Therefore, preferable implementation method of the present invention is to determine the cross section part of housing selectively.According to an improved place of the present invention is further to change cross section according to its position along the shell length axle.The cross section that for example is designed to allow to insert the housing section location of roller has reduced requirement of strength.In this zone, roller shaft effectively is not bearing on the relative surface of shell with the action of the clamping on the pipe.And, on this zone pipe, seldom or often do not compress action usually.On the other hand, the promptly so-called control area of flowing of housing working portion is long more usually, and then structure must consider in advance that generally measure is to prevent producing big power because of roller, housing and compacted pipe interact.

Therefore, consider discussed with stress and the distortion and so on all relevant factors, be used for the control section that flows according to a kind of clamping device housing new and uniqueness and new improved roller clamping device that uses with the intravenous drip device of the present invention, a housing has:

A. a thick cross section top edge or a wall that is used for housing.

B. a thin sidewalls housing.

C. one of housing thick diapire (but do not resemble top edge wall thick).

The proportionate relationship of roof section thickness and sidewall section thickness is very important, is in 1.5 to 4.0 scope according to the present invention.

Notice that be used to make bending or deflection to minimize according to the thick cross section top edge of (a), because this distortion can be very big, and a thick cross section can make it minimize.Second judgement to above-mentioned (a) is that the degree that makes roller shaft apply bigger local power place's surface of shell local deformation and impression minimizes.

Above-mentioned (b) is used to reduce material weight and utilizes the advantage of the fact of being out of shape the less fact and the big pulling force of thin plastics wall energy processing when tension.

Above-mentioned (c) is used for strengthening (but must be no more than) diapire minimizes bending or deflection.

Above-mentioned parameter (a) is designed to be used to make housing to bear a generation bending that applies by roller shaft or the bigger power of deflection.Parameter (c) is designed to bear a same similar relative power that produces bending or deflection, but this power is because the compacted part transmission by the flexible plastic pipe and applying, so distribution is more.

When being positioned at central authorities, roller will produce maximum deflection when equidistant with the housing two supports.Therefore, the axial alignment portion of upper wall portion should locate thicker than two ends.Yet because there be not " draft angle " that can make its demoulding in moulded parts, moulded parts will shrink and catch core rod securely when common injection molding, so unactual concerning the injection molding part.Yet a kind of compromise of reality is to be designed to reduce at the small end place housing wall thickness near housing, does not reduce at the end place that opens of housing.

Creep and cold flow (can occur to more in the flexible plastic tube that compressing usually) can take place in the roller of clamping device and housing.The load that applied this moment will inevitably make part exceed its elastic limit.If have creep and cold flow, then accessory size is understood time to time change, and load does not then change, and this will make the flow rate of fluid by compacted pipe change in time.For avoiding this undesirable phenomenon, reply load is limited, or the cross section that makes wall enough big (correspondingly intensity height) to prevent above elastic limit or so that minimise stress.On the other hand, because strain generally all is accompanied by stress, so must take measures in advance to prevent distortion.Usually preferably in elastic limit, work.

Because part described in the present invention is made of plastics and is preferably molded, for suitable injection mould, need " injection " cross section or duct in the part to guarantee that fused plastic resin is easy to flow so that promptly fill with whole die cavity usually in 350 to 500 temperature range.If duct or injection cross section are too little, then fused plastics just " have frozen " with very fast cooling and before finishing injection.At the lower temperature place because plastics viscosity and temperature relation are very close, so the viscosity that is injected into plastic resin with height to the result that may cause the part injection.Though and duct or injection cross section can be exempted part injection problem too greatly, can cause that part uses the plastic resin of excessive (and expensive) and will unnecessarily increase and be used for and to be injected into plastic cool to the time (thereby production cost) that formation of parts discharge die cavity still can be able to be kept the temperature of its new formation shape (not warpage).Usually, under linear condition, the time that stops in the mould, long then molding costs increased.That is, if double by the circulation time with moulding press production moulded parts, then molding costs also will double.

About molding process and mould design, importantly the suitable selection of duct, the mode cross section size of correct design and position and combination make part have enough rigidity and intensity when bending, deflection or stretch mode so that needed intensity to be provided for the present invention, and the part of abundant shaping is provided.Therefore, the preferred versions that is used for suitable molding die has the outer wicking surface of inner chamber and certain size and position, and has following demand for independence:

The injector tunnel of (1) one appropriate size or injection cross section, suitable but little to unnecessarily increasing pts wt and/or the production cycle of slowing down.

The bending of (2) one sizes and location-appropriate or stretching cross section are in order to provide required rigidity or bending, suitably but not too big.

(3) have the suitably wall of thin cross section, can satisfy other requirements of hot strength and part globality and adopt minimum plastics, and help shortening cool time with the speed production time so that gross weight is lighter.The speed production time can be improved output on a given interval and machine, the typical case for example, cross section doubles and then molded part cool time and respective molded cost improves four times.

As mentioned above, housing top wall is made thicker in to obtain the necessary intensity of required bending stiffness and the local power because of roller shaft of preventing produces excessively and is pressed into (impression).

Yet wall portion is thick just to need the long period to cool off usually, and this is a steps necessary in the injection molding.Long cool time is because molded circulation time is longer, so manufacturing cost is higher.Above-mentioned full content all is correct and real when under having the situation that a thickness and other two coordinate dimensions be in a ratio of little part a coordinate dimension being cooled off.

Yet, under other size situations, compare with the thickness situation perpendicular to thickness, effectively cooling is two coordinate dimensions, required time is much less correspondingly.Therefore, for avoiding undue cool time, the thickness wall top side must have a width of comparing with its width.This possesses a dual function, and two coordinate dimensions cooling faster both was provided, and provides a very big flow channel so that fill with the thin sidewalls portion of the vicinity of housing for injecting molten plastic again.

Another aspect of the present invention is relative portability, can be used for existing mould is improved to obtain benefit of the present invention.Characteristics comprise by two die cavitys, half one being abutted against together to be done relatively simply to change to injecting die cavity to produce thinner sidewall (must bear tensile force in the use).

Other characteristics comprise: (1) moves core rod with respect to die cavity so that the roller shaft guide portion thickness (providing required bending strength and anti-roller shaft to be pressed into) of housing (a) is provided, (b) determine that the position of molded inlet is to guarantee the good distribution of molten plastic, (c) significantly reduce housing clamping surface wall thickness (because the cross-sectional area of its wall was bigger originally), (d) in housing, have heat passage (cooling) that it is introduced and keep two coordinate directions than the heavy wall cross-section at the roller shaft guide, produce molded circulation time to reduce.

Under the situation of housing in the span of control that flows, be according to housing cross section of the present invention:

1. sidewall thickness is not for being out of shape 1.2-2.2 times (not being 2.2-3 times) of (name) flexible plastic tube wall thickness.

2. roof thickness (roller shaft guide) is 1/2 times of 2-3 not being out of shape the flexible plastic tube wall (in typical scope or thicker).

3. bottom wall thickness is less than or equal to roof thickness (being different from common equating).

4. sidewall thickness is the 0.3-0.6 (being different from common equating) of roof thickness.

As previously mentioned, the ratio of roof tranverse sectional thickness and sidewall tranverse sectional thickness is in the 2-5 scope.

Further concrete condition will be explained below.And realize aforementioned goal of the invention by this way.

The present invention has many other advantages and other purposes, but these advantages and purpose will be by to the considerations of various forms of implementation of the present invention and more clear and obvious.Some example of these forms has been shown in the accompanying drawing and has constituted the part of this description.Now these forms are described specifically, in order to set forth total principle of the present invention; But should understand these specific descriptions can not be as the restriction to content of the present invention.

Fig. 1 is the axonometric chart of typical prior art clamping device;

Fig. 2 is the cutaway view of the popular form clamping device that uses in the prior art;

Fig. 3 is the cutaway view according to a clamping device housing of the present invention;

Fig. 4 is the sketch map of prior art mould;

Fig. 4 A is to Fig. 4 similar figure of expression according to mould of the present invention;

Fig. 5 is an improvement form (left side) that compares new parts and the sketch map (right side is depicted as traditional cross section) that its effect is described.

Referring to Fig. 1 and 2, also can be used for an inclined ramp clamping device though should understand the present invention, but for the purpose of explanation, the horizontal movement clamping device 10 of prior art is shown, clamping device 10 comprises that a housing 12 1 takes the roller of roller 14 forms, and roller has a roller shaft 16 that is placed in the groove that forms in the housing top.In this schematic form, housing comprises a lower surface 17, and the latter is provided with a groove 18, is depicted as a V-shaped groove for purposes of illustration, interval 19 ccontaining pipes 20 between roller bottom surface and the surface 17, fluid flows with a controlled way according to the roller position by this pipe.Although also can adopt the plastic pipe of other medical grade, tubing is generally the used plastized polyvinyl chloride of intravenous drip device in the past.The internal diameter of these pipes is generally the 2.3-3.0 millimeter, and external diameter is generally the 3.5-4.5 millimeter, and its Shore hardness is between 68-80.The cross section of groove vary along its length in order to change fluid the cross-sectional area by pipe.

For this horizontal movement clamping device, the effect of roller is to close for above-mentioned reason fully compresses the pipe sidewall, and the variable cross section groove then is used to change the portion that opens of pipe with the control fluid flow.In the illustrated form, the control area of flowing extends to zone 23 from zone 22, and low surface comprises a protruding vertical member 25, and just it still operates as a locking member in the upstream of this projection vertical member 25 even close the closed zone, closes fully in order to guaranteeing.In fact, be arranged in the end of groove and also do not flow in the zone before the projection at roller.As shown in the figure, in this form, by provide in periphery with flow in the control area surface 17 basically near or exactly parallel axial trough, roller approaches usually along advancing of its track but needn't be exactly parallel in mobile control area.Roller advancing on part 25 is not parallel, but as previously mentioned, there is no the control of flowing in this zone.The typical case for example, idler wheel bottom and gap between surperficial 17 are not more than two times of nominal wall thickness of the used pipe 20 of clamping device.Owing to can adopt the pipe of various sizes, the gap in the control area of flowing between surface 17 and the idler wheel bottom can change to another kind of size from a kind of clamping device of size pipe, to keep fully clamping in each side of pipe.The clamping device structure (not shown) that also has is closed so a side at pipe fully clamps owing to be designed to tube chamber one side closure that flows.

Referring to Fig. 2, can see that the cross section of housing 12 is even substantially, be approximately 0.3-0.5 times of tube outer diameter, generally between 1.2 millimeters to 1.7 millimeters, shell length is between 20 millimeters to about 55 millimeters.Can see uniform cross-sectional area from the cross section of diapire 17a, it forms the wall 18a in surface 17 and the groove 18.The sidewall 27 of housing and 28 and the section thickness of diapire 17a and sidewall 18a basic identical.Comprise one have

wall

27,29 cross

section part wall

27,28 and form between the

wall portion

31,32 of wall of the gudgeon groove that roller shaft 16 advances therein a transition zone 29 arranged.This transition zone comprises and forms the following shoulder 31a and the 32a of the groove that wheel shaft 16 is advanced thereon.Shoulder 31a and 32a top are apical margin or roof 36 and 37 of housing, and the latter forms the top of gudgeon groove.As shown in the figure, the tranverse sectional thickness of apical margin or roof and

sidewall

27,28 are basic identical.

Figure 3 shows that a preferred versions of the present invention, still is horizontal movement clamping device form, and it has various parts, housing, V-shaped groove, roller, pipe etc., as previously mentioned.For purposes of illustration, only housing 50 is discussed here.Clamping device housing cross section can be divided into three districts, each district all satisfies according to each special requirement of the present invention.

Comprise that apical margin or

roof

51,52 and

gudgeon shoulder

53,54 should be able to bear with the top district on top and

wall

61,62 because the bending load (arching) that tube grip and the wheel shaft that changed by a position apply on shell length.The gudgeon of roller is bearing in clamping process on the downside 51a and 52a of apical margin or roof.Downside should be able to bear being absorbed in as the result of clamping action and wheel shaft that applies by the wheel shaft with relative little radius of curvature or gudgeon.Distant requirement be in molding process, be provided with one flow passage be used to inject molten plastic pass major part or preferably part whole axial length and be not exposed to a large contact surface, this contact surface causes cooling, too greatly then causes premature setting as this contact surface.Also have a lateral flow to be used to form sidewall 57 and 58.In addition, for ease of flowing,

apical margin

51 and 52 cross section approach circle, as shown in the figure.

Second district is the lateral areas, and it consists essentially of

sidewall

57,58 and wall portion, and wall portion comprises

shoulder

53,54 and cell wall or upper whorl axial guiding wall portion 61,62.This lateral areas must have enough intensity with bear fully produce in the clamping device by clamping the tensile force that action causes.This lateral areas must have less but enough flow cross sections, is used to inject molten plastic and flows through that vertical distance does not have too early cooling with the lateral areas portion that is full of housing fully and just solidify before being full of this zone.At first enter the position of " inlet " of die cavity according to molten plastic, also can require the lateral areas have one with the cross section that is full of the one adjacent region without its oneself inlet.

The wall portion that the base area consists essentially of diapire 60 and formed by dredging flow groove 65, it should be able to bear the bending load similar to pushing up the district.The bending load of base area is similar to top district, yet because to be applied to bending load on the base area be that full diameter by roller applies, next compresses by the pair of lamina flexible plastic tube again, and the needs of opposing loading of pressing in have just significantly reduced.

And, since the cross-sectional area of base area have than about the top district in conjunction with the bigger width of width, the depth dimensions of base area must be littler of to realize bearing the required cross-sectional area of bending load.

Also have some other load that will run into and requirements.If but above-mentioned requirements suitably satisfied, these load and requiring usually in rational safety range then.

These requirements can be by various relations shown below the approximate range of shell dimension satisfied:

(1) sidewall thickness be not distortion (name) flexible plastic tube wall thickness 0.8-2.5 doubly;

(2) roof thickness is 1/2 times of the 2-3 of not distortion (name) flexible plastic tube wall thickness;

(3) bottom wall thickness be roof thickness 0.4-1.0 doubly;

(4) sidewall thickness be roof thickness 0.3-0.8 doubly;

(5) one clamping devices, the weight of housing and length are than less than 1.6 gram per centimeters, and intensity can compress and fully close an internal diameter is that 2.3 to 3.0 millimeters, external diameter are that 3.5 to 4.5 millimeters, Shore hardness surpass 68 and are not more than 80 pvc pipe;

(6) one sidewall thickness form mobile control area less than 2/3 of wall thickness in the last Wheel-guiding portion in this zone of housing;

(7) one sidewall thickness are less than bottom wall thickness;

(8) one sidewall thickness are less than 1/4 of roller full diameter width;

(9) one sidewall thickness are less than pipe 2 1/2 times of compacted pipe wall thickness under deformation state not;

(10) by under the mobile controlled situation of pipe, the ratio of a sidewall thickness and roof thickness on clamping device length less than 0.7;

(11) one roofs are of a size of the ratio of thickness and width in its cross section in 0.5 to 1.0 scope.

The clamping device housing also can have a roof roller guide portion, and the ratio of the width of its cross section and height is less than 2.0.

Therefore, the present invention has comprised a kind of like this clamping device housing, and (inlet portion and by fully closing) reduces in first control area relatively the time at the thickness that can be forced into appropriate section in the zone of realize flowing control or closing with pipe for its roof, sidewall and/or bottom wall thickness.

Another aspect of the present invention is the grade that can improve existing mold, and the present invention can be used to produce the mould of the used housing of roller type clamping device, and it is improved to the many desirable characteristics of the present invention that comprise.Described method is all applicable to tilt roller clamping device or horizontal movement clamping device.

Typical clamping device housing cross section as shown in Figure 2.Fig. 3 illustrates a preferred embodiment scope.Note, the structure of comparison diagram 2 and Fig. 3, structure of the present invention amplifies the cross section on last Wheel-guiding

surface

51,52, the constant substantially or attenuate slightly of lower gripping surface 60, the thickness of

sidewall

57,58 then reduces greatly.Fig. 5 is for ease of sketch map relatively.

Lower gripping surface can and should be done thinlyyer than upper surface.This is because of the width of its width greater than the upper whorl axial guiding surface.Upper surface and lower surface are subjected to bending force about equally.Under the similar situation of other sizes, nominally proportional with cross-sectional area for the opposing of bending.Therefore, for an equilibrated structural design, the bottom clamping surface is preferably thin cross section.

Because the opening that allows roller to advance, the width on last Wheel-guiding surface be less than lower surface, and should increase Wheel-guiding thickness and cross section on this for the suitable opposing of bending with to the opposing of wheel shaft impression in order to guarantee.

The sidewall cross-sectional area significantly reduces because of adopting thin-walled.This is because the basic load when clamping device uses is a pulling force.Owing to generally adopt ABS, polystyrene and other thermoplastic materials, hot strength is high and its stretch modulus is little.Therefore can be by at the suitable design of practical application saving in weight greatly.

In the manufacture process, nearly all roller (and screw) infusion clamping device all tends to adopt injection molding.Its inner surface and outer surface are processed into tapering (pattern draft) and are beneficial to molding, available simple two molded works of flat board.Under the situation of horizontal movement clamping device, this pattern draft provides a low-angle on clamping surface; Yet as previously mentioned, this low-angle (for example in 1/2 degree scope) is inoperative to the control of flowing.Required function, easy to use, be convenient to regulate, the pipe clamping is tight etc. all depends on Model Design.This core rod has formed the internal structure and the size of housing just.The size of core rod, shape, dimensional tolerance etc. have determined the performance of moulded parts.Therefore, for nearly all clamping device, the function of designed part depends primarily on core rod; And die cavity shape and size etc. are normally by determining what a uniform wall thickness derived out simply for part, and this wall thickness is generally in 0.045-0.060 inch scope.

On the contrary,, constitute improved key element and aspect cavity design, done nearly all thing, what then almost need not to do in the core rod design according to the present invention.For an existing mold is changed, the die cavity halves is shootd off slightly, as illustrating and will further specifying, connected again then.Simultaneously die cavity is also moved slightly with respect to core rod.Core rod is then motionless substantially, and inlet then is repositioned onto injected plastic is flow on the roller guiding surface that existing quilt thickeies.

A typical housing cavity design becomes almost or accurately symmetry of a grab type and halves 70 and 75 in the mould, sees Fig. 4.As is generally known, in molding process, also to use a core rod that is arranged in die cavity 76.For this prior art mould that is used for producing a prior art clamping device, two relative simple steps of needs are used to produce the improved mould according to improved clamping device of the present invention.

1. two mating half sections of the die cavity relatively little amount of need shooting off, its order of magnitude is the 40-80% of origianl wall thickness.Fig. 4 A is depicted as the situation that surperficial 70A, 70B, 75A and 75B are planed.The part wall thickness should have a suitable tapering (thin slightly and generally big slightly at housing small end place at the big end of housing place, should keep this tapering then; One typical pattern draft is for making wall thickness at per inch length variations some thousandths of inch.Pattern draft is used for being convenient to take out part from mould.) this little tapering can be kept by the material of removing (shooting off) equal depth along the contact surface of die cavity half one usually.

2. shown in Fig. 4 A,, can partly remove small quantity of material from the die surface that is formed on the outside of guide roller on the molded shell by separately with the die cavity halves.In Fig. 4 A, these surfaces are identified as 70C and 75C.Because this is only in this specific regions, some significant dimensions of molded part then do not change as the critical shape that is formed by core rod.

Above effect is each half one of making die cavity near an amount that equals the 25-60% of grand master pattern product wall thickness.The vertical of core rod moves generally in the 20-70% of former roof thickness scope.

These two steps are carried out fairly simple, and can carry out very soon by lower cost.Not quite need to improve the core rod part of more expensive usually mould according to the method.The more not expensive cavity section of mould only need be done a less processing.On the contrary, as adopt a new multi-cavity mold structure, then cost is much higher.

Another cost relatively is the production cost of new improved part and the comparison of former cost of parts.For example, weight minimizing 30% generally can be converted into total cost of production minimizing 20%.Its reason is that the cost of raw material accounts for most in total cost of production.Because new design should also will further save production cost greatly with the operation of production cycle faster.This is because part wall portion is thinner, and because the thickening part is subjected to cooling rather than a direction cooling of both direction, so required cool time is shorter.

Inlet is installed in the appropriate location will keeps newly-designed all advantages.A logical position arrangement is at the roller shaft guiding surface one end place of housing plastics to be injected die cavity (edge inlet).For this position arrangement, the injected plastic flow channel should have one and promptly be approximately a circular cross section and can not be too little near desired shapes.Should " feed in raw material " for desired remainder in mobile duct then than thin sidewalls and housing die cavity.The another kind of position arrangement of inlet is the end place injected plastic (but also CONSIDERING EDGE inlet) at the housing bottom clamping surface.Here flow cross section also greatly also passes to thin-walled well.For guaranteeing that a part has symmetry characteristic, to adopt a pair of inlet in the relative both sides of die cavity usually, or adopt a bigger inlet that is positioned at central authorities, the position of this central inlet is usually in the center of bottom clamping surface.

Fundamentally, the low-cost improvement requires die cavity is done suitable change, comprises the planing of halves contact surface and increases the roller shaft surface a little.In addition, core rod is moved in the 25-70% scope a little to thicken roof and to make the diapire attenuate with respect to die cavity in a direction.

Reflect that with the making new die improving the way that designs compares, the potential economic interests that obtained by the tool change method are very big comparatively speaking.This is because these manufacturers that can obtain immediate interest have had big production mould and had very big market occupancy volume.Can be with a very suitable cost with the very suitable downtime that is used to change its mould is improved.

Should be appreciated that the present invention is not limited to the detailed description in the concrete preferred versions of the present invention is described.Those skilled in the art can improve according to above-mentioned disclosure, but these improvement of carrying out according to institute's disclosure all do not break away from the spirit and scope of the present invention that proposed by claims.

Claims

1. the molded roller type clamping device of plastics has a housing, and above-mentioned housing has an at least one bottom surface and a roof, it is characterized in that, the ratio of the tranverse sectional thickness of described roof and the tranverse sectional thickness of sidewall is in the 1.5-4.0 scope.

2. the molded roller type clamping device of plastics as claimed in claim 1 is characterized in that, described clamping device is a horizontal movement clamping device.

3. plastic roller formula clamping device, has a housing, one roller and be pressed in roller and housing between plastic tube, it is characterized in that, described housing has a Weight-to-Length Ratio less than 1.6 gram per centimeters, and has one and can compress fully that to close an internal diameter be that 2.3 millimeters, external diameter are that 3.5-4.5 millimeter, Shore hardness surpass 68 polyvinyl chloride pipe.

4. plastic roller formula clamping device as claimed in claim 3 is characterized in that, described clamping device is a horizontal movement clamping device.

5. plastic roller formula clamping device as claimed in claim 3 is characterized in that, described sidewall is 0.8-2.5 a times of described plastic tube wall thickness.

6. plastic roller formula clamping device as claimed in claim 5 is characterized in that, described clamping device is a horizontal movement clamping device.

7. plastic roller formula clamping device, has a housing that comprises a sidewall and a upper whorl axial guide portion, one has the roller of a wheel shaft, described housing has the part of a formation one mobile control area, it is characterized in that, in described mobile control area, the cross section of sidewall is less than 2/3 of upper whorl axial guide portion thickness.

8. plastic roller formula clamping device as claimed in claim 7, it also comprises the plastic tube that is pressed between roller and the housing, it is characterized in that, described sidewall thickness less than compacted pipe at its not during deformation state two times of wall thickness.

9. plastic roller formula clamping device as claimed in claim 7 is characterized in that, described sidewall thickness is less than half of upper whorl axial guide portion wall thickness.

10. plastic roller formula clamping device as claimed in claim 7 is characterized in that, described clamping device is a horizontal movement clamping device.

11. a plastic roller formula clamping device has a housing that comprises a sidewall and a diapire, a roller and be pressed in roller and shell bottom wall between plastic tube, it is characterized in that the thickness of described sidewall is less than half of described bottom wall thickness.

12. plastic roller formula clamping device as claimed in claim 11 is characterized in that described housing comprises a upper whorl axial guide portion, described sidewall thickness is less than 2/3 of described upper whorl axial guide portion or described bottom wall thickness.

13. plastic roller formula clamping device as claimed in claim 12 is characterized in that, described clamping device is a horizontal movement clamping device.

14. a plastic roller formula clamping device assembly that is used for the intravenous drip device comprises:

One injection molding housing comprises the sidewall that separates, a roof, and a bottom surface, Wheel-guiding portion and be arranged on wherein roller guiding device on,

One roller has one for moving the wheel shaft that is provided with along described housing axis usually, and described wheel shaft is placed in the described roller guiding device,

Described roller has one can leave a spatial size between the relative part of the bottom surface of described housing and described roller,

The deformable plastic pipe unit is placed in the described housing, and it comprises one in described space and the part between described bottom surface and described roller, and

The ratio of roof tranverse sectional thickness and sidewall tranverse sectional thickness is in the 1.5-4.0 scope.

15. the plastic roller formula clamping device assembly that is used for the intravenous drip device as claimed in claim 14 is characterized in that, described clamping device assembly has one can be to the roller travel range regulated by flowing of described pipe,

Described roller can advanced with respect to described bottom surface is parallel to the roller travel range of being regulated that flows by described pipe.

16. the plastic roller formula clamping device assembly that is used for the intravenous drip device as claimed in claim 14 is characterized in that described size gap is not out of shape two times of wall thickness less than described pipe.

17. plastic roller formula clamping device assembly as claimed in claim 14, it is characterized in that, described housing has a Weight-to-Length Ratio less than 1.6 gram per centimeters, and has one and can compress fully that to close an internal diameter be that 2.3 millimeters, external diameter are that 3.5-4.5 millimeter, Shore hardness surpass 68 polyvinyl chloride pipe.

18. plastic roller formula clamping device assembly as claimed in claim 14 is characterized in that, described sidewall thickness less than compacted pipe at its not during deformation state two times of wall thickness.

19. plastic roller formula clamping device assembly as claimed in claim 14 is characterized in that, described sidewall is 0.8-2 a times of described plastic tube wall thickness.

20. plastic roller formula clamping device assembly as claimed in claim 14 is characterized in that the cross section of sidewall in described mobile span of control is less than 2/3 of upper whorl axial guide portion thickness.

21. plastic roller formula clamping device assembly as claimed in claim 20 is characterized in that, described sidewall thickness is less than half of upper whorl axial guide portion.

22. plastic roller formula clamping device assembly as claimed in claim 14 is characterized in that, the thickness of described sidewall is less than half of described bottom wall thickness.

23. plastic roller formula clamping device assembly as claimed in claim 14 is characterized in that the thickness of described sidewall is less than 2/3 of described upper whorl axial guide portion or described bottom wall thickness.

24. a plastic roller formula clamping device assembly that is used for the intravenous drip device comprises:

One roller has for moving the wheel shaft that is provided with along described housing axis usually, and described wheel shaft is placed in the described roller guiding device,

The deformable plastic pipe unit is placed in the described housing, and it comprises one in described space and the part between described bottom surface and described roller,

Described clamping device has one and does not have the control area of flowing between an inlet portion of housing and a closed position, and

The thickness of roof, sidewall and diapire do not have to flow the control area with pipe being compressed relatively with the appropriate section that realizes flowing control or close occasion, have a less thickness.

25. a plastic roller formula clamping device assembly that is used for the intravenous drip device comprises:

One injection molding housing comprises the sidewall that separates, a roof, and a bottom surface, one wherein is provided with the last Wheel-guiding portion of a roof Wheel-guiding portion,

The ratio that described roof Wheel-guiding portion has a width and a height is less than 2.0 cross section.

26. one kind is carried out improved method to a mould that is used to make plastic roller clamping device housing, it is characterized in that, described mould has been used to produce the roller with a top wall portion and has clamped device case, described method comprises with respect to die cavity and moves core rod to thicken the measure of molded housing top wall thickness along a direction that this amount of movement is in the 20-70% of former roof thickness scope.

27. one kind is carried out improved method to a mould that is used to make plastic roller clamping device housing, it is characterized in that, described mould has been used to produce the roller with a top wall portion and has clamped device case, its medial wall is close mutually thereby described method comprises the die cavity of revising described mould becomes injection molded part to have the measure step of the sidewall thinner than the moulded parts of producing with this mould before improving, with and amplitude of fluctuation in the 25-60% of described housing origianl wall thickness scope.

28. one kind be used for to one comprise two die cavity half ones and a core rod, produce the plastic roller clamping device and carry out being improving one's methods of reducing cost with the mould of housing, described housing comprises a wheel axle support surface and a pipe pressing surface, described method not only can alleviate the case weight while greatly but also provides a kind of shell structure that respective material intensity still can be arranged and be more suitable for the molded requirement of high speed, comprises following measure step:

Manufacture and design described each die cavity half one more close mutually, make it 25-60%, to reduce moulded parts weight into former moulded parts sidewall thickness; And

Make core rod move an amount that equals the 20-60% of grand master pattern product sidewall thickness perpendicular to the direction of die cavity half one with respect to die cavity, improve the bending strength of wheel axle support surface with thickness by the big pipe pressing surface of corresponding minimizing one.