Press For A Deformable Bag

Abstract

A press for a deformable bag, particularly a blood bag, has two flaps articulating on a common hinge and urged together by pressure means to clamp a bag placed between them. Associated with the pressure means are control means adapted to make a determined pressure threshold perceptible to an operator.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a press employed for the utilization of the contents of a deformable bag, particularly for the utilization of the contents of a blood bag, that is to say a bag containing blood previously taken from a donor.

It relates more particularly to a press adapted to apply a certain pressure to a deformable bag of this kind.

As is known, the blood contained in a blood bag may be used either completely for a blood transfusion or partially after separation by extraction of at least some of its constituents.

In emergency and revival services it is frequently necessary to accelerate a blood transfusion which is being made.

2. Prior Art

At the present time it is customary for this purpose to deliver air under pressure into the blood bag in order to drive out more quickly towards the recipient the blood contained therein.

This penetration of air under pressure into a blood bag entails the risk of bubbles being carried along by the blood which could cause bubbles of air capable of giving rise to air embolism in the recipient ; in addition, this air under pressure also entails the risk of causing hemolysis of the blood with which it is in contact, as well as polluting it.

It has also been proposed to accelerate a blood transfusion by applying an external pressure to the blood bags used for the transfusion.

In order to do this devices have already been proposed which consist essentially of a sleeve or a casing in which the blood bag is placed and to which an internal pressure, which acts externally on the blood bag, is applied by inflation. In this case however it is not possible for the operator to control the pressure thus applied to the blood bag, and this may be dangerous to the recipient or in any case may give rise to the sudden bursting of the blood bag if the mechanical characteristics of the latter should be exceeded.

In addition, for the purpose of partial extraction of at least some of the constituents of the contents it is known to place a blood bag in a press, known as an extraction press and formed of two flaps articulating on a common hinge, said flaps being subjected to pressure means enabling them to clamp between them the bag so placed.

Here again, these means of applying pressure are however generally uncontrolled, while in addition an extraction press of this kind is not suitable for use for effecting an accelerated blood transfusion.

The object of the present invention is to provide a press for a deformable bag, particularly for a blood bag, which is free from the abovementioned disadvantages and in particular is capable of being used both for an accelerated blood transfusion and for extraction by separation of the constituents of the contents of said bag.

SUMMARY

According to the invention a press for a deformable bag, particularly for a blood bag, comprises two flaps articulating on a common hinge and pressure means adapted to urge said flaps towards one another in order to clamp a bag placed between them, said pressure means being associated with control means adapted to make a determined pressure threshold perceptible to an operator.

According to one particular embodiment this control is obtained from an abrupt increase of the friction forces to be overcome in order to operate the pressure means.

In another embodiment, this control is obtained from the reading of a pressure gauge connected to an aneroid capsule associated with one of the flaps of the press.

In all cases the operator using this press is warned when the pressure applied by him reaches a determined threshold.

Furthermore, as was mentioned above, the press according to the invention is capable of being used as an extraction press. For this purpose one of its flaps is extended beyond the hinge by which the other flap is articulated to it, in such a manner as to form a plate adapted to be inserted into a slot provided for the purpose in a support base associated with said press.

Because of these two possible uses a press according to the invention, the cost price of which moreover is modest while its operation is easy and reliable, offers the advantage of enabling the overall amount of equipment required by a transfusion center to be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view in perspective, by way of example, of a press according to the invention ;

FIG. 2 is a view in elevation of this press when used for an accelerated blood transfusion ;

FIG. 3 is a diagrammatical view in elevation of the press when used for a partial extraction of the contents of a blood bag ;

FIG. 4 is a partial view illustrating a modified construction of the press according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the embodiment illustrated in FIGS. 1 and 2, a press according to the invention comprises two flaps 10, 11 articulating on a common hinge 12.

The flap 10 is preferably of metal and preferably has a gutter-shaped profile.

The flap 11 is preferably transparent ; it is for example a sheet of synthetic material sold under the commercial name "Plexiglas." Near one of its transverse edges this flap 11 is provided with a simple slot 13 by which it is engaged on the hinge 12. If desired the flap 10 may be formed of a transparent synthetic material.

This hinge 12 is a simple metal plate fixed by screws 14 to the flap 10 and has a free edge 15 rolled into the shape of a crook, on which the flap 11 is engaged by its slot 13.

The flap 10 forms so-to-speak the base flap of the press and is extended beyond the hinge 12 by a plate 16, the purpose of which will be described below. This plate 16 is pierced by a hole 17.

The flap 10 also carries a stud 18 the purpose of which will be described below, and in a corresponding position the flap 11 is provided with an aperture 19 by which it can be engaged on said stud 18.

On the flap 10 there is secured a strap 20, which in the embodiment illustrated is in the form of a stirrup. The side branches 21 of said stirrup are articulated by screws 22 on the side edges of the flap 10 ; its central bar 23 has an aperture 24 engaging a tapped bush 25 formed by a male element 26 and a female element 27, the two elements being clamped on said central bar 23.

A threaded rod 28, hereinafter referred to as the clamp screw, is engaged by its screwthread in the tapped bush 25 and can be turned by means of a knob 29.

At its free end said clamp screw 28 is hollowed axially to form a blind recess 30 and widens externally to form a radial collar 31.

In the blind recess 30 in the clamp screw 28 there is disposed a calibrated spring 32 bearing against the bottom of said blind recess ; at its other end said spring is engaged on a centering stud 34 mounted on a support plate 35, which it thus presses against the flap 11; in contact with said flap 11 the support plate 35 carries axially a centering boss 36 engaged in a complementary depression 37 provided for the purpose in the surface of the flap 11 ; the relative roles of said boss and depression could obviously be reversed.

Engagement means are in addition provided between the clamp screw 28 and the support plate 35 in order to make said clamp screw and said plate integral in rotation beyond a predetermined axial movement of said clamp screw.

In the example illustrated these engagement means comprise a bent finger 40 carried radially by the collar 31 of the clamp screw 28 and a pin 41 carried radially by the support plate 35.

As an alternative these engagement means could comprise projections or depressions formed on the clamp screw 28, or more precisely on the collar 31 of the latter, to cooperate with complementary depressions or projections provided on the support plate 35.

During an accelerated blood transfusion the press according to the invention is put into action by laying flat the flap 10 of the latter (FIG. 2), then placing a blood bag 50 in position on said flap 10 ; the suspension hole 51 usually provided in a bag of this kind is engaged over the stud 18 formed on the flap 10 of the press.

The flap 11 is then folded down on to the blood bag 50, the stirrup 20 is engaged over said flap 11, the support plate 35 being brought into contact with said flap 11 and centered on the latter by means of its boss 36 and of the depression 37 in said flap.

By rotation the operator then effects an axial movement of the clamp screw 28 in the direction of the flap 11.

This axial movement causes progressive compression of the spring 32, thus applying pressure to the blood bag 50.

In the course of the axial displacement of the clamp screw 28, the latter first turns alone.

When the collar 31 of the clamp screw 28 comes into contact with the support plate 35, the bent finger 40 carried by the former comes to bear against the pin 41 carried by the support plate 35, said pin 41 being positioned on the circular path followed by the said bent finger 40.

Consequently, the support plate 35 is then driven by the clamp screw 28 which, because of the resistance produced by the friction between the support plate 35 and the flap 11, has the effect of causing the operator to increase abruptly the effort required to continue turning the clamp screw 28.

The operator is thus warned that he has reached a certain pressure threshold, determined by the compression of the calibrated spring 32 when the collar 31 of the rod 28 is in contact with the support plate 35 ; the spring 32 is therefore selected in accordance with the pressure threshold to be respected.

When the press according to the invention is used as an extraction press (see FIG. 3), the plate 16 formed by the flap 10 is engaged vertically in a slot 52 formed for the purpose in a base 53. The press is then fastened in said base by a screw 54 which passes through the hole 17 in the plate 16 formed by the flap 10.

In accordance with the modified embodiment illustrated in FIG. 4, the control means associated with the clamp screw 28 comprise an aneroid capsule 60 carried on its inner face by the flap 11. This aneroid capsule 60 is connected to a pressure gauge 61 carried by the flap 11 on its outer face and visible to the operator.

Claims

What I claim is:

1. A press for a deformable blood bag comprising two flaps, a common hinge pivotally connecting said flaps to one another, a strap fastened to one of said flaps remote from said hinge, a tapped bush fixed to said strap, a manually rotatable threaded clamp screw engaged by a screw thread in said bush and extending in the direction of the other flap,

a support plate which is in frictional contact with said other flap, and a calibrated spring disposed between and acting between said clamp screw and said support plate, the support plate being provided with engaging means adapted to connect said plate for rotation with the threaded clamp screw after a predetermined axial movement of the said threaded clamp screw.

2. A press according to claim 1, wherein the threaded clamp screw has hollowed in it a blind axial recess against which the calibrated spring bears and which terminates in a radial collar adapted to come into contact with the support plate when said spring is compressed.

3. A press according to claim 1, wherein said engaging means adapted to connect the support plate on the threaded clamp screw comprise a bent finger carried radially by said screw and a pin carried radially by said plate, said pin being positioned in the circular path followed by said bent finger.

4. A press according to claim 1, wherein centering means are provided between the support plate and said other flap, and wherein said means are formed as a boss carried by one of said parts and a recess complementary to said boss provided in the other part, in the axis of said plate.