JP2012179240A - Syringe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a syringe capable of retaining a state of a gasket abutting on the bottom of a barrel and capable of releasing the state with simple operation.SOLUTION: The syringe 1 includes: the bottomed cylindrical barrel 2 having a mouth 22 for sucking or discharging a liquid at the distal end and opened at the proximal end; the gasket 6 inserted into the barrel 2; a plunger 3 for moving the gasket 6 along the axial direction of the barrel 2; a plurality of projections 41a and 41b disposed in the barrel 2 in such a way as displaceable in the radial direction; a flange 33 disposed in the plunger 3 to be engaged with the plurality of projections 41a and 41b; and a locking means 8 for restraining the plunger 3 from moving in the axial direction of the barrel 2 as the plurality of projections 41a and 41b are engaged with the flange 33 when he gasket 6 abuts on the bottom of the barrel 2.

Description

  The present invention relates to a syringe.

  For example, a syringe used to administer a liquid such as a drug solution to a patient generally includes an outer cylinder having a mouth portion protruding from a distal end portion, and a flange (finger rest portion) formed at a proximal end portion of the outer cylinder. And a gasket inserted into the outer cylinder and a pusher for moving the gasket along the axial direction of the outer cylinder.

  Conventionally, as such a syringe, one that restricts the range in which the pusher moves in the axial direction of the outer cylinder is known so that the gasket does not move to the proximal end side from a predetermined position of the outer cylinder (for example, , See Patent Document 1).

  For example, the syringe described in Patent Document 1 includes an engagement portion provided on the outer cylinder side and an engagement portion provided on the pusher in a state where the gasket is located in the middle of the outer cylinder in the axial direction. By engaging, the pusher is prevented from moving in the proximal direction from the position.

  Such a syringe according to Patent Document 1 cannot restrict the movement of the pusher while the gasket is in contact with the bottom of the outer cylinder. Therefore, for example, when the liquid in the syringe is injected into the vial, there is a problem that the pusher is returned without permission due to an increase in the pressure in the vial.

  Moreover, in FIG. 2 etc. of patent document 1, the syringe of the structure which can perform both the control | control of the movement to the base end side of a pusher and the cancellation | release is disclosed, but in a syringe of this structure, a pusher is not used. There is a problem that the operation of rotating around the axis is required and the operability is poor.

JP 2003-265607 A

  An object of the present invention is to provide a syringe that can maintain and release the gasket in contact with the bottom of the outer cylinder with a simple operation.

Such an object is achieved by the present inventions (1) to (7) below.
(1) a bottomed cylindrical outer cylinder having a mouth part for sucking or discharging a liquid at a distal end part and having a proximal end part opened;
A gasket inserted into the outer cylinder;
A pusher for moving the gasket along the axial direction of the outer cylinder;
The outer cylinder includes a first engagement portion that is displaceable in a radial direction thereof, and a second engagement portion that is provided on the pusher and that can engage with the first engagement portion. When the gasket contacts the bottom of the outer cylinder, the first engagement portion is displaced in the radial direction of the outer cylinder, and the first engagement portion and the second engagement are Locking means for restricting movement of the pusher in the axial direction of the outer cylinder by engaging with a portion;
The locking means includes an operation portion that releases the engagement between the first engagement portion and the second engagement portion by being pressed in the radial direction of the outer cylinder. Syringe.

  (2) Move the pusher toward the tip of the outer cylinder until the gasket contacts the bottom of the outer cylinder without rotating the pusher about its central axis with respect to the outer cylinder. The syringe according to (1), wherein the first engagement portion and the second engagement portion engage with each other.

(3) The first engaging portion includes a plurality of protruding portions protruding inward of the outer cylinder,
Said 2nd engaging part is a syringe as described in said (2) comprised by the flange provided in the middle of the said pusher.

  (4) The syringe according to (3), wherein the lock unit includes a plurality of elastic portions that bias the plurality of protrusions toward the inside of the outer cylinder.

(5) The locking means includes a pair of ring-shaped pressing members that are stacked on each other and are displaceable in one direction along the radial direction of the outer cylinder,
The pair of pressing members is provided with at least one protrusion and the elastic portion on one side of the one pressing member in the one direction, and the other pressing member in the one direction. At least one of the protruding portion and the elastic portion is provided on the other side portion;
The elastic part of the one clamping member contacts the other clamping member, and the elastic part of the other clamping member contacts the one clamping member. Syringe.

  (6) The operation unit according to (4) or (5), wherein the operation unit includes a part of an outer peripheral part of the one pressing member and a part of an outer peripheral part of the other pressing member. Syringe.

  (7) The syringe according to any one of (1) to (6), wherein the lock means includes a portion that functions as a finger contact portion that has a shape protruding in opposite directions via the central axis of the outer cylinder 2. .

  According to the present invention, when the gasket is in contact with the bottom of the outer cylinder in a state where the lock member is mounted on the pusher, the engaging portion of the locking member and the outer peripheral portion of the flange portion of the outer cylinder are engaged. This restricts the movement of the pusher in the axial direction of the outer cylinder. Therefore, it is possible to maintain the state where the gasket is in contact with the bottom of the outer cylinder.

  Further, the engaging portion of the lock member is displaced in the radial direction of the outer cylinder, and the engaging portion of the lock member and the outer peripheral portion of the flange portion of the outer cylinder are engaged. Therefore, it is possible to maintain the state where the gasket is in contact with the bottom of the outer cylinder by a simple operation of pushing the pusher without rotating the pusher.

  Furthermore, by disengaging the engagement portion of the lock member in the radial direction of the outer cylinder, the engagement between the engagement portion of the lock member and the outer peripheral portion of the flange portion of the outer cylinder can be released. Therefore, the release of the locked state in which the gasket is kept in contact with the bottom of the outer cylinder can be performed with a simple operation.

It is a perspective view which shows embodiment of the syringe of this invention. It is a perspective view which shows the base end part (base end part in the state which removed the lock mechanism) of the outer cylinder of the syringe shown in FIG. It is a perspective view which shows the locking mechanism of the syringe shown in FIG. It is a top view which shows a pair of clamping member of the locking mechanism shown in FIG. It is a longitudinal cross-sectional view which shows the locked state of the syringe shown in FIG. It is a figure for demonstrating cancellation | release of the locked state of the syringe shown in FIG.

Hereinafter, the syringe of this invention is demonstrated in detail based on suitable embodiment shown to an accompanying drawing.
FIG. 1 is a perspective view showing an embodiment of the syringe of the present invention, FIG. 2 is a perspective view showing a base end portion (base end portion in a state where a lock mechanism is removed) of the outer cylinder of the syringe shown in FIG. 3 is a perspective view showing the locking mechanism of the syringe shown in FIG. 1, FIG. 4 is a plan view showing a pair of clamping members of the locking mechanism shown in FIG. 3, and FIG. 5 is a lock of the syringe shown in FIG. FIG. 6 is a view for explaining the release of the locked state of the syringe shown in FIG. 5.

  In the following description, for convenience of explanation, the right side in FIGS. 1, 5, and 6 will be described as “front end” and the left side as “base end (rear end)”.

  As shown in FIG. 1, the syringe 1 includes an outer cylinder 2, a gasket 6 that can slide within the outer cylinder 2, a pusher 3 that moves the gasket 6 along the axial direction of the outer cylinder 2, And a lock mechanism 7 attached to the base end portion of the outer cylinder 2.

  As will be described in detail later, in such a syringe 1, the lock mechanism 7 is engaged with the pusher 3 when the gasket 6 comes into contact with the bottom of the outer tube 2, and the pusher 3 is attached to the outer tube 2. It has a function of restricting movement in the axial direction.

Hereinafter, each part which comprises the syringe 1 is demonstrated sequentially.
The outer cylinder 2 is formed of a bottomed cylindrical member, and a mouth portion 22 whose diameter is reduced with respect to the body portion of the outer cylinder 2 is integrally projected at a tip portion thereof, that is, a central portion of the tip side bottom portion. Has been. From the mouth portion 22, a liquid such as a chemical solution is sucked or discharged. Further, a hub provided at a proximal end portion of a puncture needle (not shown) is detachably connected to the mouth portion 22.

  The base end portion of the outer cylinder 2 is open, and a flange 23 is integrally formed on the base end portion of the outer cylinder 2, that is, the outer periphery of the base end of the outer cylinder 2 (see FIG. 2).

  The flange 23 is a portion to which a lock mechanism 7 described later is attached, and has a portion that protrudes to the outside of the outer cylinder 2. A pair of claws 92 of the support member 9 of the lock mechanism 7 to be described later are engaged with both ends of the flange 23 in one direction along the radial direction of the outer cylinder 2. Thereby, the lock mechanism 7 is attached to the flange 23.

  Further, the flange 23 is provided with a pair of guides 24 projecting toward the base end side and parallel to each other at both ends in one direction along the radial direction of the outer cylinder 2.

  The pair of guides 24 regulates the moving direction of a pair of pinching members 4 a and 4 b of the lock mechanism 7 described later in one direction along the radial direction of the outer cylinder 2.

Each pair of guides 24 is formed with a notch 25 into which a projection 44a of the clamping member 4a and a projection 44b of the clamping member 4b described later are inserted. Thereby, the moving range of each clamping member 4a, 4b is controlled by the predetermined range.
A scale (not shown) indicating the amount of liquid is attached to the outer peripheral surface of the outer cylinder 2.

  The constituent material of the outer cylinder 2 is not particularly limited. For example, polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, polystyrene, poly- (4-methylpentene-1), polycarbonate, acrylic resin, acrylonitrile- Various resins such as polyesters such as butadiene-styrene copolymer, polyethylene terephthalate, polyethylene naphthalate, butadiene-styrene copolymer, polyamide (for example, nylon 6, nylon 6,6, nylon 6,10, nylon 12). Among them, resins such as polypropylene, cyclic polyolefin, and polyester are preferable because they are easy to mold and have low water vapor permeability. In addition, it is preferable that the constituent material of the outer cylinder 2 is substantially transparent in order to ensure internal visibility.

  A gasket 6 made of an elastic material is inserted into the outer cylinder 2. A plurality of (two in the present embodiment) ring-shaped protrusions are formed on the entire outer periphery of the gasket 6, and these protrusions are in close contact with the inner peripheral surface of the outer cylinder 2. By sliding, liquid-tightness can be more reliably maintained and slidability can be improved.

  The gasket 6 is formed with a hollow portion that opens to the base end face. In the hollow portion, a head portion of a pusher 3 described later is inserted. Irregularities are formed on the inner surface of the hollow portion of the gasket 6.

  The constituent material of the gasket 6 is not particularly limited. For example, various rubber materials such as natural rubber, butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, silicone rubber, polyurethane, polyester, polyamide, Examples thereof include elastic materials such as various thermoplastic elastomers such as olefins and styrenes, or mixtures thereof.

The pusher 3 has a rod-shaped main body 31.
The main body 31 has a cross-shaped cross section. That is, the main body portion 31 is provided with equiangular intervals in the circumferential direction, and is formed with four ribs that protrude in the radial direction and are formed along the axial direction of the pusher 3.

  A head portion that is inserted into the hollow portion of the gasket 6 and connected to the gasket 6 is formed on the distal end side of the main body portion 31. On the outer periphery of the head portion, irregularities that can fit with the irregularities on the inner surface of the hollow portion of the gasket 6 are formed. By this fitting, the gasket 6 and the pusher 3 are connected. In addition, the gasket 6 and the pusher 3 are not limited to the connection by the concave-convex fitting, but may be, for example, a structure connected by screwing or the like, a structure fixed by adhesion, fusion, or the like, or an integrally molded structure. .

A disc-shaped flange 32 is formed on the base end side of the main body 31.
Further, a flange 33 is also formed in the middle of the main body 31.

  The flange 33 is an engagement portion (second engagement portion) that engages with a plurality of protrusions 41a and 41b of the lock mechanism 7 described later when the pusher 3 is pushed all the way to the distal end side.

  Further, an inclined surface 331 having a convex curve is formed on the surface of the flange 33 on the tip side. Thereby, the flange 33 can be smoothly pushed to the tip side.

  The constituent material of the pusher 3 is not particularly limited, and the same materials as those exemplified as the constituent material of the outer cylinder 2 described above can be used.

Here, the lock mechanism 7 will be described in detail.
The lock mechanism 7 functions to restrict the movement of the pusher 3 in the axial direction of the outer cylinder 2 by engaging with the flange 33 of the pusher 3 when the gasket 6 contacts the bottom of the outer cylinder 2. It is what has. That is, the lock mechanism 7 and the pusher 3 constitute a lock unit 8 that restricts the pusher 3 from moving in the axial direction of the outer cylinder 2 when the gasket 6 comes into contact with the bottom of the outer cylinder 2.

  Further, the lock mechanism 7 has a shape in which the outer shape protrudes in opposite directions via the central axis of the outer cylinder 2 and also has a function as a finger pad. Therefore, when using the syringe 1, the user puts his / her finger on the distal end side of the lock mechanism 7 and uses it. That is, the finger pad is provided on the distal end side of the lock mechanism 7. On the other hand, operation units 42 a and 42 b described later are provided on the outer peripheral portion of the lock mechanism 7. Therefore, when the syringe 1 is used, even if the finger is put on the lock mechanism 7 and used, the lock operation and the release operation of the lock mechanism 7 can be smoothly performed without being disturbed.

  Such a locking mechanism 7 includes a pair of pressing members 4a and 4b that are stacked on each other and a support member that collectively supports the outer cylinder 2 in a state where the pair of pressing members 4a and 4b are stacked. 9.

  Each of the pair of pinching members 4a and 4b has a ring shape. The pair of pinching members 4a and 4b are provided so as to be movable along the pair of guides 24 described above. That is, the pair of pressing members 4 a and 4 b are provided so as to be displaceable in one direction along the radial direction of the outer cylinder 2.

  The pinching member 4a has an operation portion 42a for pressing the pinching member 4a on a part of the outer peripheral portion thereof. Similarly, the pinching member 4b has an operation part 42b for pressing the pinching member 4b on a part of the outer peripheral portion thereof.

  By pressing the operating portions 42a and 42b, the pressing members 4a and 4b move in a direction orthogonal to the central axis of the outer cylinder 2, that is, in one direction along the pair of guides 24.

  Further, the clamping member 4a has a plurality of protruding portions 41a protruding inward at a portion opposite to the operation portion 42a. Similarly, the pinching member 4b has a plurality of protruding portions 41b protruding inward at a portion opposite to the operation portion 42b. More specifically, a plurality of protrusions 41a are provided on one side of the pinching member 4a in the one direction, and a plurality of protrusions 41b on the other side of the pinching member 4b in the one direction. Is provided.

  The plurality of projecting portions 41 a of one clamping member 4 a and the plurality of projecting portions 41 b of the other clamping member 4 b are arranged to face each other with the central axis of the outer cylinder 2 interposed therebetween.

  Each protrusion 41a, 41b is an engaging portion (first engaging portion) that engages with the outer peripheral portion of the flange 33 of the pusher 3 when the gasket 6 contacts the bottom of the outer cylinder 2.

  An inclined surface 411a is formed on the base end side of each protrusion 41a, and similarly, an inclined surface 411b is formed on the base end side of each protrusion 41b (see FIG. 4). Thereby, the pusher 3 can be smoothly moved to the tip side until the gasket 6 contacts the bottom of the outer cylinder 2.

  Furthermore, the pinching member 4a has a pair of elastically deformable elastic portions 43a protruding from the outer peripheral portion on the same side as the protruding portions 41a. Similarly, the pinching member 4b has a pair of elastic parts 43b that protrude from the outer peripheral part and can be elastically deformed on the same side as the protruding part 41b.

  And each elastic part 43a of one clamping member 4a contacts the inner part of the operation part 42b of the other clamping member 4b, and similarly each elastic part 43b of the other clamping member 4b. Is in contact with the inner portion of the operation portion 42a of the one pressing member 4a.

  By arranging the pair of elastic portions 43a and the pair of elastic portions 43b in this manner, the plurality of protrusions 41a and the plurality of protrusions 41b are urged to the inside of the outer cylinder 2 and an external force is applied. In a natural state, the distance between the tips of the plurality of protrusions 41 a and the tips of the plurality of protrusions 41 b is slightly smaller than the diameter of the flange 33 of the pusher 3.

  In addition, the plurality of protrusions 41a and the plurality of protrusions 41b are displaced in a direction away from each other against the elastic force of the elastic parts 43a and 43b, so that the tips of the plurality of protrusions 41a and the plurality of protrusions are displaced. The distance between the tip of 41b can be made larger than the diameter of the flange 33 of the pusher 3.

  In addition, a pair of protrusions 44a protruding in a direction orthogonal to the direction in which the operation portion 42a is pressed are provided on the outer peripheral portion of the pinching member 4a. Similarly, a pair of protrusions 44b that protrude in a direction orthogonal to the direction in which the operation portion 42b is pressed are provided on the outer peripheral portion of the pinching member 4b.

  Although not shown, one projection 44a of the clamping member 4a and the projection 44b on the same side as the one projection 44a of the clamping member 4b are both in the notch 25 of the outer cylinder 2 described above. It is inserted from the inside. Similarly, the other projection a of the clamping member 4a and the projection b on the same side as the other projection a of the clamping member 4b are both inserted from the inside into the other notch 25 of the outer cylinder 2 described above. Has been.

  The support member 9 that supports the pair of pinching members 4 a and 4 b has a main body portion 91 and a pair of claws 92 that protrude from the main body portion 91 toward the distal end side.

  The main body 91 has an annular shape that covers the pair of pressing members 4a and 4b from the base end side and has an opening through which the pusher 3 is inserted.

  The pair of claws 92 projecting from the main body 91 is engaged with the front end side surface of the flange 23 of the outer cylinder 2 described above. As a result, the support member 9 is fixed to the outer cylinder 2, and the pair of pressing members 4 a and 4 b are supported by the support member 9.

  The support member 9 supports the pair of clamping members 4a and 4b so as to be movable along the pair of guides 24 described above.

  Moreover, it does not specifically limit as a constituent material of each part which comprises such a lock mechanism 7, The thing similar to what was illustrated as a constituent material of the outer cylinder 2 mentioned above can be used.

  According to the locking means 8 configured as described above, when the pusher 3 is moved until the gasket 6 comes into contact with the bottom of the outer cylinder 2, first, the inclined surface 331 of the flange 33 of the pusher 3. Moves toward the tip side while contacting the inclined surface 411a of each protrusion 41a of the lock mechanism 7, so that the plurality of protrusions 41a are opposite to the central axis of the outer cylinder 2 against the elastic force of the elastic part 43a. Displace to the side. Similarly, when the inclined surface 331 of the flange 33 of the pusher 3 moves to the base end side while being in contact with the inclined surface 411b of each protruding portion 41b of the lock mechanism 7, the plurality of protruding portions 41b are elastic of the elastic portion 43b. Displace to the opposite side of the central axis of the outer cylinder 2 against the force. Thereby, the distance between the front-end | tip of several protrusion part 41a and the front-end | tip of several protrusion part 41b is expanded.

  When the flange 33 of the pusher 3 exceeds the plurality of protrusions 41a and the plurality of protrusions 41b, the plurality of protrusions 41a and 41b are centered on the outer cylinder 2 by the elastic force of the elastic parts 43a and 43b that are elastically deformed. As shown in FIG. 5, it is displaced to the shaft side and engages with the base end side surface of the outer peripheral portion of the flange 33.

  The engagement of the plurality of protruding portions 41 a and 41 b with the flange 33 of the pusher 3 restricts the pusher 3 from moving in the axial direction of the outer cylinder 2. That is, when the pusher 3 is moved until the gasket 6 contacts the bottom of the outer cylinder 2, the engagement between the plurality of protrusions 41 a and 41 b and the flange 33 causes the pusher 3 to move in the axial direction. The position can be locked.

  Such a locked state can be released by applying an external force to the central axis side of the pusher 3 with respect to the operation portions 42a and 42b of the pair of pressing members 4a and 4b. More specifically, in the locked state, the operator pushes in a state in which the operator applies a force (force in the direction indicated by arrow a in FIG. 6) to bring the pair of operation units 42a and 42b closer to each other. By pulling the child 3 toward the base end, the engagement between the plurality of projecting portions 41 a and 41 b and the flange 33 can be released.

  In this manner, the engagement between the plurality of projecting portions 41 a and 41 b and the flange 33 can be released by a pressing operation in the radial direction of the outer cylinder 2. Thereby, engagement with the some protrusion part 41a, 41b and the flange 33 can be cancelled | released by simple operation. Moreover, the operation | movement mentioned above can be repeatedly performed by canceling | releasing engagement with the some protrusion parts 41a and 41b and the flange 33. FIG.

  Further, the lock means 8 including the pair of pinching members 4a and 4b as described above is small, and the operability of the syringe 1 can be improved.

  According to the syringe 1 as described above, when the gasket 6 comes into contact with the bottom of the outer cylinder 2, the plurality of protrusions 41 a and 41 b and the flange 33 are engaged with each other, so that the pusher 3 is moved to the outer cylinder 2. It is restricted to move in the axial direction. Therefore, the state where the gasket 6 is in contact with the bottom of the outer cylinder 2 can be maintained. That is, when the pusher 3 is pushed all the way to the distal end side of the outer cylinder 2, the state can be locked.

  Further, the plurality of protrusions 41 a and 41 b are displaced in the radial direction of the outer cylinder 2, and the plurality of protrusions 41 a and 41 b and the flange 33 are engaged. Therefore, it is possible to maintain the state in which the gasket 6 is in contact with the bottom portion of the outer cylinder 2 by a simple operation of pushing the pusher 3 without rotating the pusher 3.

  Furthermore, the plurality of projecting portions 41 a and 41 b are displaced in the radial direction of the outer cylinder 2, whereby the engagement between the plurality of projecting portions 41 a and 41 b and the flange 33 can be released. Therefore, the release of the locked state can also be performed by a simple operation of moving the pusher 3 toward the proximal end while grasping the pair of operation portions 42a and 42b.

  In particular, a first engaging portion constituted by a plurality of projecting portions 41 a and 41 b projecting inside the outer cylinder 2, and a second engaging portion constituted by a flange 33 provided in the middle of the pusher 3, By realizing the locked state as described above by the engagement, the locking means 8 can be miniaturized and the operability of the syringe 1 can be improved.

  As mentioned above, although the syringe of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is substituted by the thing of the arbitrary structures which have the same function. Can do. In addition, any other component may be added to the present invention.

  For example, in the above-described embodiment, the case where the first engagement portion is configured by the two pairs of protrusions 41a and 41b has been described as an example. However, the number of protrusions constituting the first engagement portion is For example, it may be 1 or more and 3 or less, or 5 or more.

  In the embodiment described above, the planar view shape of the flange 33 provided on the pusher 3 is circular. However, the planar view shape of the flange 33 is not limited to this, and for example, a square, pentagon, hexagon A polygon such as a square may be formed. Moreover, the 2nd engaging part provided in a pushing element is not limited to what makes a flange shape, For example, it may be at least 1 protrusion which protrudes outside from the center axis | shaft side of a pushing element.

  Further, the outer shape of the lock mechanism 7 is not limited to that described above. However, it is preferable that the outer shape of the lock mechanism 7 has a shape protruding in opposite directions to each other via the central axis of the outer cylinder to the extent that it can function as a finger pad. In addition, you may provide a finger pad part in an outer cylinder separately from a locking mechanism.

  Further, the syringe of the present invention can be applied to, for example, a prefilled syringe in which a chemical solution or the like is stored in a space (liquid storage space) previously surrounded by an outer cylinder and a gasket, and a normal syringe. .

DESCRIPTION OF SYMBOLS 1 Syringe 2 Outer cylinder 3 Pusher 4a Clamping member 4b Clamping member 6 Gasket 7 Lock mechanism 8 Locking means 9 Support member 22 Mouth 23 Flange 24 Guide 25 Notch 31 Body part 32 Flange 33 Flange 41a Protruding part 41b Protruding part 42a operation part 42b operation part 43a elastic part 43b elastic part 44a protrusion 44b protrusion 91 body part 92 nail 331 inclined surface 411a inclined surface 411b inclined surface

Claims (7)

A bottomed cylindrical outer cylinder having a mouth part for sucking or discharging liquid at the distal end part and having a proximal end part opened;
A gasket inserted into the outer cylinder;
A pusher for moving the gasket along the axial direction of the outer cylinder;
The outer cylinder includes a first engagement portion that is displaceable in a radial direction thereof, and a second engagement portion that is provided on the pusher and that can engage with the first engagement portion. When the gasket contacts the bottom of the outer cylinder, the first engagement portion is displaced in the radial direction of the outer cylinder, and the first engagement portion and the second engagement are Locking means for restricting movement of the pusher in the axial direction of the outer cylinder by engaging with a portion;
The locking means includes an operation portion that releases the engagement between the first engagement portion and the second engagement portion by being pressed in the radial direction of the outer cylinder. Syringe.   In a state where the pusher is not rotated around its central axis with respect to the outer cylinder, the pusher is moved toward the tip of the outer cylinder until the gasket contacts the bottom of the outer cylinder, The syringe according to claim 1, wherein the first engaging portion and the second engaging portion are engaged. The first engaging portion is composed of a plurality of protruding portions protruding inside the outer cylinder,
The syringe according to claim 2, wherein the second engagement portion is configured by a flange provided in the middle of the pusher.   The syringe according to claim 3, wherein the lock means includes a plurality of elastic portions that urge the plurality of protrusions toward the inside of the outer cylinder. The locking means includes a pair of pinching members in a ring shape that are overlapped with each other and provided so as to be displaceable in one direction along the radial direction of the outer cylinder,
The pair of pressing members is provided with at least one protrusion and the elastic portion on one side of the one pressing member in the one direction, and the other pressing member in the one direction. At least one of the protruding portion and the elastic portion is provided on the other side portion;
The elastic part of the one clamping member is in contact with the other clamping member, and the elastic part of the other clamping member is in contact with the one clamping member. Syringe.   The syringe according to claim 4 or 5, wherein the operation part is configured by a part of an outer peripheral part of the one pressing member and a part of an outer peripheral part of the other pressing member.   The syringe according to any one of claims 1 to 6, wherein the locking means has a portion functioning as a finger contact portion having a shape protruding in opposite directions via the central axis of the outer cylinder 2.

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