RU2644696C1 - Three-component syringe of one-time use - Google Patents

Abstract

FIELD: medical equipment.

SUBSTANCE: invention relates to medical equipment, namely, three-piece syringe of one-time use intended for injection and other medical procedures connected with pouring or suction of liquid. Device is a three-component single use syringe, in which the elastic piston is designed as a double-sided ferrule with oppositely directed working edges. Working edge of the rear ferrule is located on the side of the rod is narrowed and does not touch the wall of the frame when it free. In the initial state, the piston is pushed into the frame firmly back, and the rear ferrule is turned outward and its working edge is tucked into the gap between the piston and the frame along the entire circle. When setting fluid, syringe’s air-tightness is ensured by the rear ferrule, pressed between the frame and the piston.

EFFECT: when the liquid is discharged, the rear ferrule by friction against the frame is turned and turns into free state, which does not ensure the air-tightness of syringe when trying to re-dial the liquid.

1 cl, 2 dwg

Description

The invention relates to medicine, in particular to disposable injection devices.

Known [Sabitov V.Kh. Medical instruments. - M .: Medicine, 1985, 175 S.] a three-component disposable syringe that contains a hollow cylindrical body with a tip and a piston made of elastic material, moved inside the body using the rod.

The disadvantages of this device include the possibility of its use an unlimited number of times.

Also known is a single-use disposable syringe [Single use disposable syringe, Patent EP 0308040 A1] and its analogues [US 4986812 A, US 5000737 A, US 5183466 A, EP 0376697 A2 and others], which contain a cylindrical body and a piston that is moved inside the body with the help of the rod, where the locking element is put on the rod in the form of an elastic metal washer (or individual sectors located in the longitudinal recesses of the rod) with external teeth in contact with the body and internal teeth in contact with the rod, which are curved in the direction of fluid collection, what allows the corp The mustache and the stem move relative to the locking element only towards the bend of the teeth.

The disadvantages of these devices include the possibility of several cycles of filling and emptying the syringe, provided that the total volume of all cycles does not exceed the nominal volume of the syringe.

Also known is a medical syringe with a piston cuff [Trusov M.M., Babkin S.I. Medical syringe with piston cuff. Copyright certificate for the invention of the USSR No. 125879, 1960], the piston of which is made in the form of a double cuff of elastic material.

The disadvantages of this device include the possibility of its use an unlimited number of times.

A medical syringe with a piston-cuff, the piston of which is made in the form of a double cuff from an elastic material, was chosen as the closest analogue.

The disadvantages of this device include the possibility of its use an unlimited number of times.

The objective of the invention is to enable only one cycle of filling-emptying the syringe.

The problem is solved due to the fact that in the design of a medical syringe with a piston-cuff, the piston of which is made in the form of a double cuff of elastic material, the following difference is provided: the edge of the back cuff directed toward the rod, the outer diameter of which in the free state is smaller than the inner diameter of the case, in the initial state, turned outward and tucked into the gap between the outer surface of the piston and the inner surface of the housing.

Between the totality of the essential features of the claimed object and the achieved technical result, there is a causal relationship, namely: the working edge of the front cuff directed towards the tip ensures the tightness of the syringe only when the fluid is released; the edge of the back cuff, turned outward and tucked into the gap between the piston and the housing, ensures the tightness of the syringe only when the piston is moved to the side of the rod during the first intake of fluid; moving the piston towards the tip when the fluid is released leads to a straightening of the edge of the back cuff due to friction against the wall of the housing and its translation into a free state; the working edge of the back cuff in the free state does not come into contact with the inner surface of the housing and does not ensure the tightness of the mating piston with the housing when moving the piston relative to the housing in any direction.

The invention allows for only one cycle of filling-emptying the syringe.

The technical nature and principle of operation of the proposed device are illustrated in the drawing, on which:

FIG. 1 - Design diagram of a three-component single-use syringe in the initial state (a) and a piston of a three-component single-use syringe in a free state (b). 1 - housing; 2 - the piston; 3 - stock; 4 - tip; 5 - edge of the front cuff; 6 - the edge of the back cuff.

FIG. 2 - Scheme of operation of a three-component single-use syringe (thick arrows indicate the direction of movement of the rod; thin arrows indicate the direction of movement of the liquid; dotted lines indicate the direction of movement of air), and a set of fluid; b - the position reached by the piston at the end of the set; in - release of fluid; g - an attempt to re-fluid.

The possibility of carrying out the claimed invention is shown by the following examples.

In the initial state (Fig. 1a), the piston (2) is pushed fully into the syringe body (1). The edge of the back cuff (6) is turned outward and tucked into the gap between the inner surface of the housing (1) and the outer surface of the piston (2). During the first fluid collection (Fig. 2a), the piston moves along the axis of the syringe away from the tip (4). In this case, the tightness of the syringe is ensured by the elastic edge of the back cuff sandwiched between the body and the piston. When the piston stops in the extreme position (Fig. 2b) achieved during the set, the tightness is ensured by both piston cuffs. During the release of fluid (Fig. 2B), the piston moves toward the tip. In this case, the edge of the back cuff due to friction against the inner surface of the housing passes into a free state (Fig. 1b) and ceases to come into contact with the inner surface of the housing. In this case, the excess pressure that occurs inside the housing under the action of the piston additionally presses the working edge of the front cuff to the inner surface of the housing, which ensures the tightness of the syringe. When you try to re-fluid (Fig. 2d) in the housing there is a vacuum, squeezing the working edge of the front cuff from the wall of the housing, as a result of which the syringe is filled with air through the occurring leaks between the piston and the housing.

The proposed three-component single-use syringe (Fig. 1a) consists of a housing (1), a piston (2) and a rod (3).

The structural elements listed above are made as follows: the casing (1) is a hollow cylinder made of rigid polymeric material that is muffled from one (front) side, the front wall of which is equipped with a conical tip (4) with an axial hole communicating with the cavity of the casing. The piston (2), made of an elastic polymer material, is a cylinder whose front and back bases have edges (5, 6) raised above the front and back surfaces with the formation of two cuffs. The outer diameter of the edge of the front cuff (5) in the free state (Fig. 1b) slightly exceeds the inner diameter of the housing (1). The outer diameter of the edge of the back cuff (6) in the free state (Fig. 1b) is slightly smaller than the inner diameter of the housing (1). The rear surface of the piston has arbitrary structural elements that secure the rod (3), which is a rigid rod of arbitrary shape, the length of which slightly exceeds the length of the housing (1), made of rigid polymeric material. In the initial state, the piston (2) is pushed into the housing (1) until it stops, while the working edge of the front cuff (5) abuts against the inner surface of the housing (1) around the entire circumference. The edge of the back cuff (6) is turned outward and tucked around the entire circumference into the gap between the inner surface of the housing (1) and the outer surface of the piston (2).

The three-component single-use syringe described above is used as follows: holding the syringe with one hand on the body (1), immerse the tip (4) with the injection needle installed if necessary, then without removing the tip (s) from the liquid, gently with the other hand pull the piston (2) by the rod (3) to the required distance. Due to the resulting vacuum, the cavity enclosed between the front wall of the housing (1) and the front surface of the piston (2) is filled with liquid. Then the tip (needle) is removed from the liquid, directed in the desired direction and the piston (2) begins to move in the opposite direction, gently pressing the rod (3) along the axis of the syringe. Due to the excess pressure that arises in this case, the fluid enclosed between the front wall of the housing (1) and the front surface of the piston (2) flows out of the syringe through the tip (needle).

Claims (1)

A three-component single-use syringe containing a hollow cylindrical body with a tip, a rod and a piston in the form of a double cuff made of elastic material, characterized in that the edge of the back cuff directed toward the rod, the outer diameter of which in the free state is smaller than the inner diameter of the body, is turned out in the initial state outward and tucked into the gap between the outer surface of the piston and the inner surface of the housing.

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