Disposable medical injector, dispensing device or medicine dissolving device provided with plastic piston

Abstract

The utility model relates to a disposable medical syringe, a dispensing device or a medicine dissolving device with a plastic piston, which comprises a needle cylinder, a push rod, a piston connector and a piston, the piston is arranged on the piston connector, the lower end of the piston connector is arranged at the upper end of the push rod, and the piston, the piston connector and the push rod are inserted into the needle cylinder. The piston is composed of a piston head and a piston sleeve which are formed through injection molding, the piston head is in a T shape, the lower end of the piston head is arranged at the upper end of the push rod, an annular groove is formed in the edge of the lower side of the upper face of the piston head, an annular boss is arranged on the upper face of the piston sleeve, the lower portion of the piston head is sleeved with the piston sleeve, and the annular boss on the piston sleeve is inserted into the annular groove in the piston head. According to the technical scheme, the two wedge-shaped inclined planes on the piston head and the piston sleeve are matched, and axial force is converted into partial radial force, so that a better sealing effect is achieved between the piston head and the needle cylinder, the use of a rubber piston is avoided, and the needle cylinder still meets the national current standard requirement after an injection molding piece is adopted.

Description

Technical Field

[0001] The utility model relates to a clinical medical device, in particular to a disposable medical syringe, a medicine dispenser or a medicine dissolving device equipped with a plastic piston. Background Art

[0002] In the prior art, an injection device with an injection capacity of less than 10 ml is usually called a syringe, and an injection device with an injection capacity of more than 10 ml is called a dispenser or a dissolver.

[0003] In the prior art, in order to ensure the sealing effect during the extraction and pushing of drugs by syringes, dispensers and dissolvers, rubber with good elastic sealing effect is mostly used as the main production material of the pistons in syringes, dispensers and dissolvers, and silicone oil diluted with hydrochlorofluorocarbons is applied to the outer edge of the piston to ensure that it achieves the desired effect.

[0004] The Ministry of Ecology and Environment issued an announcement on September 1, 2023 that the disposable medical device industry will completely ban the use of hydrochlorofluorocarbons as silicone oil diluents and cleaning agents, and proposed a final deadline of December 1, 2023. Utility Model Content

[0005] In view of this, the main purpose of the utility model is to provide a disposable medical syringe, dispenser or dissolver equipped with a plastic piston. Through the technical solution, the axial force is converted into partial radial force by utilizing the cooperation between the two wedge-shaped inclined surfaces on the piston head and the piston sleeve, thereby achieving a better sealing effect between the piston head and the syringe.

[0006] In order to achieve the above-mentioned purpose, the technical scheme of the utility model is implemented as follows: a disposable medical syringe, a dispenser or a dissolver equipped with a plastic piston, comprising a syringe, a push rod, a piston connector and a piston, wherein the piston is arranged on the piston connector, the lower end of the piston connector is arranged on the upper end of the push rod, the piston, the piston connector and the push rod are inserted in the syringe, the piston is composed of an injection-molded piston head and a piston sleeve, the piston head is T-shaped, the lower end of the piston head is arranged on the upper end of the push rod, an annular groove is arranged at the lower side edge of the piston head, an annular boss is arranged on the piston sleeve, the piston sleeve is sleeved on the lower part of the piston head, and the annular boss on the piston sleeve is inserted in the annular groove on the piston head.

[0007] As a further technical solution, the inner side surface of the annular groove of the piston head is an annular inclined inner surface that is retracted inward from bottom to top into the annular groove, and the outer bottom of the annular groove is provided with a first working inner surface that is inclined outward toward the annular groove; the inner side surface of the annular boss of the piston sleeve is an annular inclined outer surface that is retracted inward from bottom to top into the annular boss, and the outer top of the annular boss is provided with a first working outer surface that is inclined outward toward the annular boss.

[0008] As a further technical solution, a transition inner surface inclined toward the annular groove is provided in the middle of the outer side of the annular groove of the piston head, and a transition outer surface inclined toward the annular boss is provided in the middle of the outer side of the annular boss of the piston sleeve.

[0009] As a further technical solution, the outer notch of the annular groove of the piston head is provided with a second working inner surface inclined outwardly of the annular groove, and the outer root of the annular boss of the piston sleeve is provided with a second working outer surface inclined outwardly of the annular boss.

[0010] As a further technical solution, a piston mounting seat is arranged inside the piston head, and several evenly distributed elastic opening grooves are radially arranged on the side wall of the piston head below the piston mounting seat. The upper part of the piston connecting head extends into the piston mounting seat by utilizing the elasticity of the elastic opening grooves on the side wall below the piston head.

[0011] As a further technical solution, when the first working inner surface of the annular groove contacts the first working outer surface of the annular boss, the lower end surface of the piston sleeve presses against the upper end of the push rod, and a gap of 0.3mm-0.6mm is left between the lower end surface of the piston head and the upper end of the push rod.

[0012] The beneficial effect of adopting the above technical solution is: a disposable medical syringe, dispenser or dissolver equipped with a plastic piston, through this technical solution, utilizes the cooperation between the two wedge-shaped inclined surfaces on the piston head and the piston sleeve to convert the axial force into partial radial force, so as to achieve a better sealing effect between the piston head and the syringe, eliminate the use of rubber pistons, and still meet the current national standards after using injection molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the overall cross-sectional structure of a medicine dispensing device or a medicine dissolving device larger than 10 ml in the utility model.

[0014] Figure 2 This is a schematic diagram of the overall cross-sectional structure of a syringe less than 10 ml in the utility model.

[0015] Figure 3 It is a schematic diagram of the overall cross-sectional structure of the residue removal syringe less than 10ml in the utility model.

[0016] Figure 4 for Figure 1 Schematic diagram of the local enlarged structure in the A direction.

[0017] In the figure, 1 is a syringe, 2 is a push rod, 3 is a piston connector, 4 is a piston head, 5 is a piston sleeve, 6 is an annular groove, 7 is an annular boss, 8 is an annular inclined inner surface, 9 is a first working inner surface, 10 is an annular inclined outer surface, 11 is a first working outer surface, 12 is a transition inner surface, 13 is a transition outer surface, 14 is a second working inner surface, 15 is a second working outer surface, 16 is a piston mounting seat, and 17 is an elastic opening groove. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0019] like Figure 1-Figure 4 As shown, the utility model relates to a disposable medical syringe, a dispenser or a dissolver equipped with a plastic piston, comprising a syringe 1, a push rod 2, a piston connector 3 and a piston, wherein the piston is arranged on the piston connector 3, the lower end of the piston connector 3 is arranged on the upper end of the push rod 2, the piston, the piston connector 3 and the push rod 2 are inserted in the syringe 1, and the piston is composed of an injection-molded piston head 4 and a piston sleeve 5, the piston head 4 is T-shaped, the lower end of the piston head 4 is arranged on the upper end of the push rod 2, an annular groove 6 is arranged on the lower side edge of the piston head 4, an annular boss 7 is arranged on the piston sleeve 5, the piston sleeve 5 is sleeved on the lower part of the piston head 4, and the annular boss 7 on the piston sleeve 5 is inserted in the annular groove 6 on the piston head 4.

[0020] As a further embodiment, the inner side surface of the annular groove 6 of the piston head 4 is an annular inclined inner surface 8 which is retracted inward from bottom to top into the annular groove 6, and the outer bottom of the annular groove 6 is provided with a first working inner surface 9 which is inclined outward of the annular groove 6. The inner side surface of the annular boss 7 of the piston sleeve 5 is an annular inclined outer surface 10 which is retracted inward from bottom to top into the annular boss 7, and the outer top of the annular boss 7 is provided with a first working outer surface 11 which is inclined outward of the annular boss 7.

[0021] As a further embodiment, a transition inner surface 12 inclined toward the annular groove 6 is provided in the middle of the outer side of the annular groove 6 of the piston head 4, and a transition outer surface 13 inclined toward the annular boss 7 is provided in the middle of the outer side of the annular boss 7 of the piston sleeve 5.

[0022] As a further embodiment, the outer notch of the annular groove 6 of the piston head 4 is provided with a second working inner surface 14 inclined outwardly toward the annular groove 6 , and the outer root of the annular boss 7 of the piston sleeve 5 is provided with a second working outer surface 15 inclined outwardly toward the annular boss 7 .

[0023] As a further embodiment, a piston mounting seat 16 is arranged inside the piston head 4, and a plurality of evenly distributed elastic opening grooves 17 are radially arranged on the side wall of the piston head 4 below the piston mounting seat 16 of the piston head 4, and the upper part of the piston connecting head 3 extends into the piston mounting seat 16 by utilizing the elasticity of the elastic opening grooves 17 on the side wall below the piston head 4.

[0024] As a further embodiment, when the first working inner surface 9 of the annular groove 6 contacts the first working outer surface 11 of the annular boss 7, the lower end surface of the piston sleeve 5 presses against the upper end of the push rod 2, and a gap of 0.4 mm is left between the lower end surface of the piston head 4 and the upper end of the push rod 2.

[0025] In the technical solution of the utility model, the piston made of rubber material used in the prior art is replaced by a piston head 4 and a piston sleeve 5 made of injection molding material, thereby eliminating the need to apply silicone oil diluted with hydrochlorofluorocarbons to the rubber piston, and meeting the national requirement that the disposable medical device industry will completely ban the use of hydrochlorofluorocarbons as silicone oil diluents and cleaning agents.

[0026] In the technical solution of the present utility model, the transition outer surface 13 and the transition inner surface 12 are non-working surfaces, which are provided in order to design the first working inner surface 9 and the second working inner surface 14 in the annular groove 6 of the piston head 4, and to design the first working outer surface 11 and the second working outer surface 15 on the annular boss 7 of the piston sleeve 5.

[0027] Among the three embodiments of the technical solution of the utility model, the first embodiment is a dispenser or dissolver with a piston head larger than 10ml and a flat needle offset, the second embodiment is a syringe with a piston head smaller than 10ml and a conical shape, and the third embodiment is a syringe with a piston head smaller than 10ml and a flat shape with a residue removal function.

[0028] In the technical solution of the utility model, for a syringe with a capacity less than 10 ml, the piston head and the push rod can also be connected in a threaded manner.

[0029] The technical solution of the utility model has two steps when in use, namely, extracting the medicine liquid and pushing the medicine liquid.

[0030] When pushing the medicine liquid, when the push rod 2 is pushed into the syringe 1, the piston head 4 forms a certain resistance under the action of the medicine liquid and the wall of the syringe 1. Since there is a 0.4mm gap between the bottom of the piston head 4 and the top of the push rod 2, and the piston sleeve 5 is pressed against the push rod 2, the push rod 2 first pushes the piston sleeve 5 at this time, so that the annular boss 7 of the piston sleeve 5 is pressed against the annular groove 6 of the piston head 4, so that the first working inner surface 9 and the second working inner surface 14 respectively press the first working outer surface 11 and the second working outer surface 15 downward, forcing the outer edge of the piston head 4 to expand radially. While maintaining this state, the push rod 2 drives the piston connector 3 to push the piston head 4 to overcome the resistance of the medicine liquid and the wall of the syringe 1 suffered by the piston head 4 to push the medicine liquid. At the same time, the piston sleeve 5 and the push rod 2 move synchronously to maintain the use state of the outer edge of the piston head 4 expanding radially, forming the best sealing effect between the syringe 1 and the piston head 4.

[0031] When extracting liquid medicine, when the push rod 2 is pulled out from the syringe 1, the piston sleeve 5 is pressed against the push rod 2. Because there is a 0.4 mm gap between the bottom of the piston head 4 and the top of the push rod 2, the piston connector 3 drives the piston head 4 to move slightly downward, causing the annular groove 6 of the piston head 4 to press tightly against the annular boss 7 of the piston sleeve 5, and the first working inner surface 9 and the second working inner surface 14 respectively press the first working outer surface 11 and the second working outer surface 15 downward, forcing the outer edge of the piston head 4 to expand radially, thereby achieving the best sealing effect between the syringe 1 and the piston head 4 when extracting liquid medicine.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A disposable medical syringe, dispenser or dissolver equipped with a plastic piston, comprising a syringe, a push rod, a piston connector and a piston, wherein the piston is arranged on the piston connector, the lower end of the piston connector is arranged on the upper end of the push rod, and the piston, the piston connector and the push rod are inserted into the syringe, characterized in that: The piston is composed of an injection-molded piston head and a piston sleeve. The piston head is T-shaped, and the lower end of the piston head is arranged on the upper end of the push rod. An annular groove is arranged on the lower edge of the piston head, and an annular boss is arranged on the piston sleeve. The piston sleeve is sleeved on the lower part of the piston head, and the annular boss on the piston sleeve is inserted into the annular groove on the piston head.

2. The disposable medical syringe, dispenser or dissolver with a plastic piston according to claim 1, characterized in that: The inner side surface of the annular groove of the piston head is an annular inclined inner surface that is retracted inward from bottom to top into the annular groove, and the outer bottom of the annular groove is provided with a first working inner surface that is inclined outward toward the annular groove. The inner side surface of the annular boss of the piston sleeve is an annular inclined outer surface that is retracted inward from bottom to top into the annular boss, and the outer top of the annular boss is provided with a first working outer surface that is inclined outward toward the annular boss.

3. The disposable medical syringe, dispenser or dissolver with a plastic piston according to claim 1 or 2, characterized in that: A transition inner surface inclined toward the annular groove is provided in the middle of the outer side of the piston head, and a transition outer surface inclined toward the annular boss is provided in the middle of the outer side of the annular boss of the piston sleeve.

4. The disposable medical syringe, dispenser or dissolver with a plastic piston according to claim 1 or 2, characterized in that: The outer notch of the annular groove of the piston head is provided with a second working inner surface inclined outwardly toward the annular groove, and the outer root of the annular boss of the piston sleeve is provided with a second working outer surface inclined outwardly toward the annular boss.

5. The disposable medical syringe, dispenser or dissolver with a plastic piston according to claim 1, characterized in that: A piston mounting seat is arranged inside the piston head, and a plurality of evenly distributed elastic opening grooves are arranged radially on the side wall of the piston head below the piston mounting seat. The upper part of the piston connecting head extends into the piston mounting seat by utilizing the elasticity of the elastic opening grooves on the side wall below the piston head.

6. The disposable medical syringe, dispenser or dissolver with a plastic piston according to claim 1 or 2, characterized in that: When the first working inner surface of the annular groove contacts the first working outer surface of the annular boss, the lower end surface of the piston sleeve presses against the upper end of the push rod, and a gap of 0.3mm-0.6mm is left between the lower end surface of the piston head and the upper end of the push rod.

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