CN204840538U - Injection with low resistance - Google Patents

Abstract

The utility model belongs to the field of medical appliances, and in particular relates to a low-resistance syringe, which includes a cylinder body, a piston and a core rod. A connecting rod is arranged at the front end of the core rod. A hollow cylinder with an open bottom, the outermost diameter of the head of the connecting rod is larger than the outer diameter of the hollow cylinder and smaller than the inner diameter of the cylinder, the head of the connecting rod is located in the cavity of the hollow cylinder; the piston is tightly sleeved on the above hollow cylinder On the outer circumference of the piston, there is an upper annular groove opening upward on the upper end surface of the piston, and a lower annular groove opening downward on the lower end surface. Sealing rings are provided on the outermost circumferences of the upper and lower end surfaces of the piston. The outer diameter of the sealing ring is larger than The inside diameter of the barrel. Since the friction between the sealing ring on the outermost circumference of the piston and the barrel changes with the change of the pressure in the barrel, the piston is easy to slide in the barrel, and the resistance is small during use. It is an ideal low-resistance syringe; the piston passes through the sealing ring Keep sealed with the cylinder without leakage.

Description

low resistance syringe

technical field

The utility model relates to a low-resistance syringe, which belongs to the field of medical appliances.

Background technique

A syringe is a commonly used medical device in clinical practice. It is usually composed of a cylinder, a piston, and a core rod. The above-mentioned syringe is generally composed of polymer materials. In order to prevent leakage between the piston and the cylinder, there is a good For the sealing effect, there must be sufficient interference between the piston and the cylinder, but the large interference makes the operator need to use a large force to move the piston. There are also glass syringes, which are usually composed of a cylinder and a core rod. The friction between the core rod and the cylinder is small, the resistance is small, and the sliding performance is excellent, but the device is easily broken during production and transportation, making it unusable.

Utility model content

Based on the above deficiencies in the prior art, the technical problem to be solved by the utility model is to provide a low-resistance syringe in which the frictional resistance between the piston and the inner wall of the cylinder can change with the pressure and can reduce the frictional resistance.

The low-resistance syringe described in the utility model includes a cylinder, a piston and a core rod. A connecting rod is arranged at the front end of the core rod. The shape of the head of the connecting rod matches the top of the cylinder. Below the head of the connecting rod is a hollow cylinder with an open bottom. , the diameter of the outermost periphery of the head of the connecting rod is greater than the outer diameter of the hollow cylinder and smaller than the inner diameter of the cylinder, the head of the connecting rod is located in the cavity of the hollow cylinder; the piston is tightly sleeved on the outer circumference of the above-mentioned hollow cylinder, and the piston There is an upper annular groove with an upward opening on the upper end surface of the piston, and a lower annular groove with a downward opening on the lower end surface. Sealing rings are provided on the outermost circumferences of the upper and lower end surfaces of the piston. The outer diameter of the sealing ring is larger than the inner diameter of the cylinder.

The inner wall of the above-mentioned hollow cylinder has an anti-off protrusion, and the corresponding anti-off protrusion is provided with an undercut block on the head of the core rod. 1. The cooperation of the anti-loosening protrusion makes the core rod engage with the connecting rod, and this structure facilitates the assembly of the head of the core rod and the hollow cylinder of the connecting rod. Preferably, the size of the undercut block on the head of the core rod is larger than the size of the anti-loosening protrusion of the hollow cylinder of the connecting rod, so that the head of the core rod can be more firmly clamped into the hollow cylinder of the connecting rod.

The longitudinal section of the notch of the upper annular groove of the above-mentioned piston is V-shaped or inverted trapezoidal, and the longitudinal section of the notch of the lower annular groove is inverted V-shaped or trapezoidal.

Working principle and process:

When the liquid is pumped, the external atmospheric pressure is higher than the pressure in the inner cavity of the cylinder and the piston, and the lower annular groove forces the sealing ring on the lower end surface to expand outward under the action of the external atmospheric pressure. The contact surface of the wall increases, and the sealing performance is enhanced. As the pressure decreases, the sealing ring on the lower end surface shrinks under the action of elasticity and returns to the original state;

When the liquid is pushed forward, the core rod is pushed, and the liquid inside the cylinder is compressed by the piston, so that the internal pressure is greater than the external pressure. The contact surface between the sealing ring and the inner wall of the cylinder increases, and the sealing performance is enhanced. As the pressure decreases, the sealing ring on the upper end surface shrinks under the action of elasticity and returns to the original state.

It can be seen from the above that the structure of the syringe is simple. Since the friction between the sealing ring on the outermost circumference of the piston and the cylinder changes with the pressure in the cylinder, the piston is easy to slide in the cylinder, and the sliding friction is small. Small, is an ideal low resistance syringe.

In addition to the above, the sealing ring on the outermost circumference of the piston is always sealed with the inner wall of the cylinder to ensure that the syringe does not leak during use.

Compared with the prior art, the utility model has the following beneficial effects:

The low-resistance syringe has a simple structure, and the friction between the sealing ring on the outermost periphery of the piston and the barrel changes with the pressure in the barrel, so that the piston is easy to slide in the barrel, and the resistance is small during use; The sealing ring is always sealed with the inner wall of the cylinder to ensure no leakage of the syringe during use.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is the structural representation of core rod;

Fig. 3 is the structural representation of connecting rod;

Fig. 4 is a schematic diagram of the structure of the piston.

In the figure: 1. Cylinder body; 2. Core rod; 3. Piston; 4. Connecting rod; 5. Head of core rod; , Anti-off protrusion; 10, upper annular groove; 11, sealing ring; 12, lower annular groove.

Detailed ways

Embodiments of the utility model are further described below in conjunction with the accompanying drawings:

As shown in Figures 1 to 4, the low-resistance syringe includes a barrel 1, a piston 3, and a core rod 2. A connecting rod 4 is provided at the front end of the core rod 2, and the shape of the head 7 of the connecting rod matches the inner top of the barrel 1. Below the rod head 7 is a hollow cylinder 8 with an open bottom. The outermost diameter of the connecting rod head 7 is greater than the outer diameter of the hollow cylinder 8 and smaller than the inner diameter of the cylinder body 1. The connecting rod head 7 is located at the center of the hollow cylinder 8. In the cavity; the piston 3 is tightly sleeved on the outer circumference of the above-mentioned hollow cylinder 8 (that is, the outer diameter of the hollow cylinder 8 is greater than the inner diameter of the piston 3), and the upper end surface of the piston 3 has an upper annular groove 10 with an upward opening, and the lower There is a lower annular groove 12 with an opening downward on the end face, and sealing rings 11 are provided on the outermost peripheries of the upper and lower end faces of the piston 3 , and the outer diameter of the sealing rings 11 is larger than the inner diameter of the cylinder 1 . In this embodiment, the shape of the inner top of the cylinder 1 is umbrella-shaped, so the head 7 of the connecting rod that matches the inner top of the cylinder 1 is also umbrella-shaped, and the angle of the umbrella shape of the connecting rod head 7 varies with the shape of the inside of the cylinder 1. The angle of the top changes.

Wherein: the inner wall of the hollow cylinder 8 has an anti-off protrusion 9, corresponding to the anti-off protrusion 9, a number of undercut blocks 6 are arranged on the core rod head 5, and the core rod head 5 is inserted into the hollow cylinder of the connecting rod 4 from below body 8 and through the cooperation of the undercut block 6 and the anti-off protrusion 9, the core rod 2 and the connecting rod 4 are engaged. This structure facilitates the connection between the core rod head 5 and the hollow cylinder 8 of the connecting rod 4. assembly. Preferably, the size of the undercut block 6 of the core rod head 5 is larger than the size of the anti-loosening protrusion 9 of the hollow cylinder 8 of the connecting rod, so that the core rod head 5 can be more firmly snapped into the hollow cylinder of the connecting rod 4 8 within. The longitudinal section of the upper annular groove 10 of the piston 3 is V-shaped or inverted trapezoidal, and the longitudinal section of the lower annular groove 12 is inverted V-shaped or trapezoidal.

Working principle and process:

When the liquid is sucked, the external atmospheric pressure is higher than the pressure in the inner cavity of the cylinder body 1 and the pressure in the piston 3, and the lower annular groove 12 forces the sealing ring 11 on the lower end surface to expand outward under the action of the external atmospheric pressure. The contact surface between the sealing ring 11 and the inner wall of the cylinder 1 is increased, and the sealing performance is enhanced. As the pressure decreases, the sealing ring 11 on the lower end surface shrinks under the action of elasticity and returns to the initial state;

When the liquid is pushed forward, the core rod 2 is pushed, and the liquid inside the barrel 1 is compressed by the piston 3, so that the internal pressure is greater than the external pressure, and the upper annular groove 10 expands the sealing ring 11 on the upper end surface outward under the pressure At this time, the contact surface between the sealing ring 11 on the upper end surface and the inner wall of the cylinder 1 is increased, and the sealing performance is enhanced. As the pressure decreases, the sealing ring 11 on the upper end surface shrinks under the action of elasticity and returns to the initial state.

It can be seen from the above that the structure of the syringe is simple. Since the frictional force between the sealing ring 11 on the outermost periphery of the piston 3 and the cylinder body 1 changes with the pressure in the cylinder body 1, the piston 3 is easy to slide in the cylinder body 1. The sliding friction is small, and the resistance is small during use. It is an ideal low-resistance syringe, and the piston 3 is always kept sealed with the inner wall of the cylinder 1 through the outermost sealing ring 11 to ensure that the syringe does not leak during use.

Claims (4)

1. A low-resistance syringe, comprising a cylinder (1), a piston (3) and a core rod (2), characterized in that: the front end of the core rod (2) is provided with a connecting rod (4), and the head of the connecting rod (7) The shape matches the inner top of the cylinder body (1). Below the connecting rod head (7) is a hollow cylinder (8) with an open bottom. The outermost diameter of the connecting rod head (7) is larger than that of the hollow cylinder (8). The outer diameter is smaller than the inner diameter of the cylinder (1), the connecting rod head (7) is located in the cavity of the hollow cylinder (8); the piston (3) is tightly sleeved on the outer circumference of the above-mentioned hollow cylinder (8), The upper end surface of the piston (3) has an upper annular groove (10) with an upward opening, and a lower annular groove (12) with an opening downward on the lower end surface, and sealing rings are provided on the outermost peripheries of the upper and lower end surfaces of the piston (3) (11), the outer diameter of the sealing ring (11) is greater than the inner diameter of the cylinder (1). 2. The low-resistance syringe according to claim 1, characterized in that: the inner wall of the hollow cylinder (8) has an anti-off protrusion (9), and the corresponding anti-off protrusion (9) is on the core rod head. The part (5) is provided with an undercut block (6), and the core rod head (5) is inserted into the hollow cylinder (8) of the connecting rod (4) from below and passes through the undercut block (6) and the anti-off protrusion The cooperation of (9) makes the core rod (2) engage with the connecting rod (4). 3. The low-resistance syringe according to claim 2, characterized in that: the size of the undercut block (6) of the core rod head (5) is larger than the anti-off protrusion of the hollow cylinder (8) of the connecting rod from (9) in size. 4. The low-resistance syringe according to claim 1 or 2, characterized in that: the longitudinal section of the notch of the upper annular groove (10) of the piston (3) is V-shaped or inverted trapezoidal, and the lower annular groove (12 ) The longitudinal section of the notch is inverted V-shaped or trapezoidal.