Patent Description:
Injection devices have been known as tools for injecting a chemical solution into a body (see Patent Literatures <NUM> and <NUM>). Such an injection device is configured to eject a chemical solution charged between a syringe and a gasket from a needle mounted on the tip of the syringe in accordance with an operation of pushing in a plunger disposed on the rear end of the gasket.

However, in the case of the conventional injection device, a user has to remove air by operating the plunger, then to stick the needle into a blood vessel, muscle, or the like while holding the tip of the syringe, and then to inject the chemical solution while holding the plunger. As seen above, in the case of the conventional injection device, the user has to switch the injection device area to be held between the syringe tip and the plunger in the course from the removal of air to the injection of the chemical solution, and the series of operations related to injection are troublesome. Moreover, when holding the plunger after sticking the needle, the needle tip may be shaken. This may damage a cell or tissue of skin or cause pain to an injection subject such as a patient.

The present invention has been made to solve the above problems, and an object thereof is to provide an injection device and injection unit that do not require frequent switching of the injection device area to be held and reduce the load on the injection subject.

The invention comprises an injection device as defined in the independent claim <NUM>. Additional features of preferred embodiments of the invention are defined in the dependent claims. An injection device according to one aspect of the present invention includes a syringe including a tubular body, the body having, in a peripheral wall, an opening having a rectangular shape in a plan view, a conversion portion connected to a rear end portion of a gasket disposed on a tip side of the body, the conversion portion being contained in the body, a button disposed on a side near the opening of the conversion portion and supported by the conversion portion with side portions of the button sandwiched between both side walls of the opening, and a slider disposed in the opening in the peripheral wall of the body and configured to move the conversion portion and the button in a tip direction that is a direction in which the gasket moves toward a tip of the body. The button has a cross-sectional U-shape on a plane perpendicular to the tip direction and includes a pair of leg portions disposed so as to straddle the conversion portion and having front slopes inclined with respect to the tip direction by a set angle. The conversion portion includes a pair of engaging portions formed so as to correspond to the pair of leg portions and having rear slopes that slidingly contact the front slopes and is configured to move in the tip direction in accordance with an operation of pushing down the button toward inside of the body.

An injection unit includes the above injection device and one or more adjustment members configured to adjust the frontmost position of the button in the opening. The one or more adjustment members include a spacer having a preset width and disposed between the side walls of the opening.

The present invention includes the conversion portion contained in the body, the button supported by the conversion portion with the side portions thereof sandwiched between the side walls of the opening, and the slider configured to move the conversion portion and button in the tip direction. The button includes the pair of leg portions having the front slopes, and the conversion portion includes the pair of engaging portions having the rear slopes. Thus, a user is able to remove air by operating the slider located on the peripheral wall of the body so that the conversion portion to which the gasket is connected moves in the tip direction and to inject a chemical solution to a human, animal, or the like by operating the button located on the peripheral wall of the body so that the conversion portion further moves in the tip direction. This eliminates frequent switching of the injection device area to be held from the series of operations related to injection and reduces the load on the injection subject.

Referring to <FIG>, an example configuration of an injection device <NUM> according to a first embodiment will be described. For convenience, an x-axis direction, a y-axis direction, and a z-axis direction in the drawings are referred to as a front-rear direction, a left-right direction, and an up-down direction, respectively. In the following description, these directions may be used to describe the orientations of the members or the positional relationships therebetween. To avoid complication, some of reference signs or the like are omitted in the drawings as appropriate.

First, referring to <FIG>, an example overall configuration of the injection device <NUM> according to the first embodiment will be described. As shown in <FIG>, the injection device <NUM> includes a syringe <NUM>, a gasket <NUM>, a conversion portion <NUM>, a button <NUM>, and a slider <NUM>. Suitable materials of the syringe <NUM> include polypropylene (PP), cycloolefin polymer (COP), polystyrene (PS), polycarbonate (PC), and the like, which have transparency. In <FIG>, the gasket <NUM>, conversion portion <NUM>, button <NUM>, and slider <NUM> seen behind the syringe <NUM> are shown by broken lines, and the inner wall of the syringe <NUM>, and the like are also shown by broken lines.

The syringe <NUM> includes a cylinder tip portion <NUM>, a body <NUM>, and a lid portion <NUM>. The body <NUM> is formed in a cylindrical shape, and the cylinder tip portion <NUM> is connected to the tip thereof. More specifically, the body <NUM> includes a cylindrical peripheral wall <NUM>, as well as includes a tip portion 12n for connecting the peripheral wall <NUM> and cylinder tip portion <NUM>. The tip portion 12n illustrated in <FIG> and the like is tapered from the peripheral wall <NUM> toward the cylinder tip portion <NUM>. The peripheral wall <NUM> of the body <NUM> is provided with an opening <NUM> having a rectangular shape in a plan view.

The body <NUM> can be divided into a chemical solution storage portion 12a, a mechanism incorporation portion 12b, and an auxiliary portion 12c in terms of functionality. The chemical solution storage portion 12a is a portion into which the gasket <NUM> is to be fitted and a chemical solution C is to be charged. The mechanism incorporation portion 12b is a portion provided with the opening <NUM> and incorporates an push-out mechanism for pushing out the gasket <NUM> in two stages. The push-out mechanism is a mechanism obtained by combining the conversion portion <NUM>, button <NUM> and slider <NUM>. The auxiliary portion 12c has a length set on the basis of the operability of the injection device <NUM>, or the like and has the lid portion <NUM> mounted on the rear end portion thereof.

The cylinder tip portion <NUM> is a cylindrical member having a smaller inner and outer diameters than those of the body <NUM>. The cylinder tip portion <NUM> is a portion that has an ejection hole 11a on the tip thereof and into which an injection needle (not shown) is to be inserted. The lid portion <NUM> is a portion for reinforcing the rear end portion of the body <NUM>. The lid portion <NUM> illustrated in <FIG> and the like has a perimeter consisting of a flat portion and a curved portion, and the flat portion is disposed on the side opposite to that on which the opening <NUM> disposed. By using the lid portion <NUM> thus shaped, the user is able to stably place the injection device <NUM> with the button <NUM> oriented upward and thus to prevent the injection device <NUM> from rolling.

The gasket <NUM> is a portion disposed near the tip of the body <NUM> and is made of an elastic material such as rubber. The gasket <NUM> is formed in a cylindrical shape so as to closely contact the inner wall 12r of the body <NUM>. The front end portion <NUM> of the gasket <NUM> is formed so as to match the shape of the inner surface of the tip of the chemical solution storage portion 12a. The front end portion <NUM> of the gasket <NUM> according to the first embodiment is tapered. The rear end portion of the gasket <NUM> is provided with a connection hole (not shown) for connecting with the conversion portion <NUM>.

The button <NUM> is disposed on the opening <NUM> side of the conversion portion <NUM> and supported by the conversion portion <NUM> with the sides thereof sandwiched between both side walls 15b (left and right side walls 15b) of the opening <NUM>. The button <NUM> has a cross-sectional U-(concave)shape on a plane perpendicular to a tip direction. The tip direction refers to the direction in which the gasket <NUM> is oriented toward the tip of the body <NUM> and corresponds to the positive x-axis direction, that is, the forward direction in the drawings.

The button <NUM> includes a face wall 41a to be pushed by a finger or the like and a pair of side walls 41b extending approximately perpendicularly to the face wall 41a from both side end portions of the face wall 41a. <FIG> shows the initial state, which is a state in which the slider <NUM> is in contact with the rear wall 15d of the opening <NUM> and the button <NUM> is in contact with the push end surface 51c of the slider <NUM>. In the initial state, the button <NUM> is disposed such that the front end surface 41c thereof is opposed to the front wall 15c of the opening <NUM> and the rear end surface 41d thereof is in contact with the push end surface 51c. As shown in <FIG>, a portion including the face wall 41a and the pair of side walls 41b and having the front end surface 41c and rear end surface 41d of the button <NUM> is referred to as a button body <NUM>.

The length Te (see <FIG>) of the gap between the front end surface 41c of the button <NUM> and the front wall 15c of the opening <NUM> in the initial state is set to a length that allows the user to remove air accumulated in the injection needle mounted on the tip of the cylinder tip portion <NUM> and the chemical solution storage portion 12a through the tip of the injection needle. That is, the length Te is set in order to remove air through the tip of the injection needle.

The button <NUM> has a pinching groove <NUM> formed along the tip direction from the rear end surface 41d. The pinching groove <NUM> according to the first embodiment is formed so as to range from the rear end surface 41d to the front end surface 41c of the button <NUM>. When the button <NUM> is pushed down, the pinching groove <NUM> pinches the core portion <NUM> of the conversion portion <NUM>. The button <NUM> includes a pair of leg portions <NUM> disposed so as to straddle the conversion portion <NUM> and each having front slopes <NUM> inclined with respect to the tip direction by a set angle θ.

The pair of leg portions <NUM> shown in the drawings each include a first leg portion 42a disposed on the gasket <NUM> side and a second leg portion 42b disposed on the slider <NUM> side. That is, the button <NUM> includes the pair of first legs 42a and the pair of second legs 42b. Hereafter, the first leg portion 42a and second leg portion 42b may be collectively referred to as the leg portion <NUM> without distinguishing them from each other. The first leg portion 42a and second leg portion 42b have, on the front side thereof, the front slopes <NUM> that slidingly contact the rear slopes <NUM> of the conversion portion <NUM>. The button <NUM> also includes a pair of come-out prevention portions <NUM> that extend rearward from lower portions of the second leg portion 42b and are to be engaged with the bottom portion 52b of a pinching portion <NUM>. The bottom portion 52b is a front-side portion of the bottom (lower surface) of the pinching portion <NUM> exposed from the auxiliary portion <NUM>. The button <NUM> is disposed such that flat surfaces 4f of upper portions of the come-out prevention portions <NUM> are opposed to the bottom portion 52b of the pinching portion <NUM>. Thus, the come-out prevention portions <NUM> are caught on the bottom portion 52b and prevent the button <NUM> from falling down.

The conversion portion <NUM> is connected to the rear end portion of the gasket <NUM> and contained in the body <NUM>. The conversion portion <NUM> includes a fitting portion <NUM> to be fitted into the connection hole of the gasket <NUM>, a neck portion <NUM> connected to the fitting portion <NUM>, the plate-shaped core portion <NUM> connected to the neck portion <NUM>, and a pair of engaging portions <NUM> disposed on both side surfaces of the core portion <NUM>. The pair of engaging portions <NUM> are formed so as to correspond to the pair of leg portions <NUM> and have rear slopes <NUM> that slidingly contact the front slopes <NUM>. That is, the inclination of the rear slopes <NUM> is equal to the inclination of the front slopes <NUM>. The conversion portion <NUM> is configured to move in the tip direction in accordance with an operation of pushing down the button <NUM> toward the inside of the body <NUM>. The direction in which the button <NUM> is pushed down toward the inside of the body <NUM> is a direction perpendicular to the tip direction and is hereafter also referred to as a "push-down direction. " The push-down direction corresponds to the negative z-axis direction in the drawings.

The engaging portions <NUM> shown in the drawings each include a first engaging portion 34a disposed on the gasket <NUM> side and a second engaging portion 34b disposed on the slider <NUM> side. The first engaging portion 34a corresponds to the first leg portion 42a and has the rear slope <NUM> that slidingly contacts the front slope <NUM> of the first leg portion 42a. The second engaging portion 34b corresponds to the second leg portion 42b and has the rear slope <NUM> that slidingly contacts the front slope <NUM> of the second leg portion 42b.

While the drawings show an example in which the second engaging portions 34b of the conversion portion <NUM> have front auxiliary slopes 3t inclined with respect to the tip direction by the set angle θ, this example corresponds to a modification B (to be discussed later). That is, the second engaging portions 34b need not have the front auxiliary slopes 3t.

The slider <NUM> is disposed behind the conversion portion <NUM> and button <NUM>. The slider <NUM> is a portion for moving the conversion portion <NUM> and button unit <NUM> in the tip direction. The slider <NUM> includes an operation portion <NUM>, the pinching portion <NUM>, the auxiliary portion <NUM>, and a safety protrusion <NUM>. The operation portion <NUM> is disposed outside the body <NUM>, and the width Ws thereof is wider than the width (W<NUM>) of the opening <NUM>. The pinching portion <NUM> is connected to the surface opposite to the operation surface 51a of the operation portion <NUM> and is disposed so as to be sandwiched between the side walls 15b of the opening <NUM>. The width of the pinching portion <NUM> is equal to or slightly smaller than the width (W<NUM>) of the opening <NUM>.

The auxiliary portion <NUM> is connected to the surface opposite to the surface of the pinching portion <NUM> connected to the operation portion <NUM> and is disposed inside the body <NUM>. The auxiliary portion <NUM> is formed such that a step is formed between the auxiliary portion <NUM> and the pinching portion <NUM> on the button <NUM> side. The bottom portion 52b to be engaged with the come-out prevention portions <NUM> is a front-lower portion of the pinching portion <NUM> that is void of the auxiliary portion <NUM>. The auxiliary portion <NUM> includes a pair of protruding portions <NUM> formed along the tip direction so as to contact the inner wall 12r of the body <NUM>. The pair of protruding portions <NUM> prevents the slider <NUM> from falling down and assists the slider <NUM> in stably sliding. The auxiliary portion <NUM> has an auxiliary end surface 53c disposed so as to be opposed to the rear end surface of the core portion <NUM> and the rear end surfaces of the come-out prevention portions <NUM>. That is, the slider <NUM> is able to stably push out the conversion portion <NUM> and button <NUM> using the push end surface 51c and auxiliary end surface 53c.

The safety protrusion <NUM> is disposed on the button <NUM> side of the operation portion <NUM> and is formed so as to be insertable into the pinching groove <NUM> of the button <NUM>. In a stretched state, the tip end surface 55c of the safety protrusion <NUM> is flush with the rear end surface 41d. The stretched state is a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the slider <NUM> is disposed in the rearmost position in the opening <NUM>. In the first embodiment, the frontmost position of the button unit <NUM> in the opening <NUM> is the position in which the button <NUM> contacts the front wall 15c, and the rearmost position of the slider <NUM> in the opening <NUM> is the position in which the slider <NUM> contacts the rear wall 15d. Thus, when the user pushes down the button <NUM>, the button <NUM> moves in the push-down direction with the rear end surface 41d contacting the tip end surface 55c. Since, in the stretched state, the rear end surface 51d of the slider <NUM> is in contact with the rear wall 15d of the opening <NUM>, movement in the front-rear direction of the button <NUM> is suppressed by the safety protrusion <NUM>. This prevents rearward movement of the button <NUM> and the conversion portion <NUM> engaged therewith. Thus, the movement in the push-down direction of the button <NUM> is converted into movement in the tip direction of the conversion portion <NUM> as it is.

The safety protrusion <NUM> illustrated in the drawings is disposed so as to range from the operation portion <NUM> to the pinching portion <NUM>. That is, the height in the up-down direction of the safety protrusion <NUM> is the sum of the height of a portion thereof connected to the operation portion <NUM> and the height of a portion thereof connected to the pinching portion <NUM>. Thus, until the push-down of the button <NUM> is complete, the safety protrusion <NUM> is able to ensure a predetermined contact range between the safety protrusion <NUM> and the button <NUM> and to guide the button <NUM> downward in a stable state. Note that the safety protrusion <NUM> may be connected only to the operation portion <NUM>.

The push-out mechanism is assembled to the syringe <NUM>, for example, in the following order.

The chemical solution C is charged into the chemical solution storage portion 12a, for example, by inserting a thin pipe such as a cannula into the tip of the cylinder tip portion <NUM>. The conversion portion <NUM>, button <NUM>, and slider <NUM> are integrally made of a resin or the like.

Next, referring to <FIG>, a specific example configuration of the syringe <NUM> will be described below. As shown in <FIG>, the length of the chemical solution storage portion 12a is represented by S<NUM>, the length of the mechanism incorporation portion 12b, that is, the length of the opening <NUM> is represented by T<NUM>, and the length of the auxiliary portion 12c is represented by S<NUM>. The length S<NUM> is set on the basis of the size of the gasket <NUM>, the preset dose of the chemical solution C, or the like. The front wall 15c may be formed such that the position thereof in the tip direction is substantially variable. That is, the syringe <NUM> may be configured such that the ratio between the length S<NUM> and the length T<NUM> can be adjusted. Thus, the dose of the chemical solution C can be adjusted, for example, by matching the amount of movement L corresponding to a stroke H with that when the length S<NUM> is maximized. The length S<NUM> is set in terms of the strength of the syringe <NUM>, the ease of holding, or the like. The length T<NUM> is set such that the tip end surface 55c of the safety protrusion <NUM> becomes flush with the rear end surface 41d of the button <NUM> in the stretched state.

A portion of the opening <NUM> extending in the tip direction from the position of the rear end surface 41d of the button <NUM> disposed in the frontmost position in the opening <NUM> is wider than the other portion. In the first embodiment, the frontmost position of the button unit <NUM> in the opening <NUM> is the position in which the button <NUM> contacts the front wall 15c. That is, the side walls 15b of the opening <NUM> are provided with steps <NUM> in positions of the rear end surface 41d of the button <NUM> in contact with the front wall 15c. The button <NUM> in contact with the front wall 15c is prevented from moving rearward by the step <NUM>, which are narrower rearward. Thus, when the user contacts the button <NUM> with the front wall 15c and then moves the slider <NUM> rearward, a situation in which the button <NUM> moves rearward in conjunction with the movement of the slider <NUM> is avoided.

The length T<NUM> of a region R<NUM> from the front wall 15c to the step <NUM> is set on the basis of the length Tk of the button <NUM>. In the first embodiment, the length T<NUM> is set so as to be equal to or slightly longer than the length Tk. The width W<NUM> of the region R<NUM> is set such that the resistance during operation is minimized, in consideration of the smoothness, stability, and the like of the push-down operation of the button <NUM>. The width of a region R<NUM> from the step <NUM> to the rear wall 15d is narrower than the width W<NUM> as a whole. In the first embodiment, with respect to the width of the region R<NUM>, the width W<NUM> of a portion inside the rear wall 15d corresponding to a length T<NUM> is narrower than the width W<NUM> of the other portion. Narrowing the width near the rear wall 15d in this manner is intended to fix the slider <NUM> in contact with the rear wall 15d. For this reason, the length T<NUM> is set so as to correspond to the rear end portion of the slider <NUM> and is much shorter than the length T<NUM>, as shown in <FIG>. It is preferable to properly adjust the width W<NUM> to the extent that the slidability of the button <NUM> and slider <NUM> is not impaired.

Next, referring to <FIG> and <FIG>, a specific configuration of the button <NUM> will be described. The pair of leg portions <NUM> each include base portions 4a extending from one of the side walls 41b. In a state in which the button <NUM> has yet to be pushed down, the base portions 4a are disposed so as to be opposed to the side wall 15b of the opening <NUM>. The base portions 4a according to the first embodiment have inwardly recessed depressions <NUM> in tip direction-side positions thereof adjacent to the side wall 15b of the opening <NUM>. In an example in <FIG>, the first leg portions 42a and second leg portions 42b have the depressions <NUM>. For this reason, the base portions 4a sandwiched between the side walls 15b of the opening <NUM> are more likely to move in the tip direction and less likely to move rearward. Thus, when the user contacts the button <NUM> with the front wall 15c and then moves the slider <NUM> rearward, movement of the button <NUM> in conjunction with the movement of the slider <NUM> is suppressed. By disposing the steps <NUM> in the opening <NUM> and forming the depressions <NUM> in the pair of leg portions <NUM>, rearward movement of the button <NUM> is more accurately prevented.

As illustrated in <FIG>, the first leg portions 42a and second leg portions 42b each include the base portion 4a extending from the side wall 41b and a fitting portion 4b extending from the base portion 4a. The fitting portion 4b includes a protruding portion <NUM> formed along the tip direction so as to contact the inner wall 12r of the body <NUM>. As shown in <FIG>, the protruding portions <NUM> are disposed on the pair of leg portions <NUM> and prevent the button <NUM> from falling down and assist the button <NUM> in stably sliding.

The opposed surfaces 4r of the fitting portions 4b are formed in a curved shape along the inner wall 12r. The opposed surfaces 4r of the fitting portions 4b are portions disposed so as to be opposed to the inner wall 12r of the body <NUM>. Thus, as is understood from <FIG>, in a state in which the button <NUM> has yet to be pushed, the range in which the pair of leg portions <NUM> and the core portion <NUM> are opposed to each other is increased. This increases the stability of the button <NUM> that is being pushed down. Also, the opposed surfaces 4r are curved to a degree similar to that of the inner wall 12r of the body <NUM>. Thus, when the button <NUM> is pushed down, the lower end portions of the fitting portions 4b are brought close to the inner wall 12r of the body <NUM> or its vicinity. Thus, the stroke H, which is the distance by which the button <NUM> can be pushed down, is maximized.

The come-out prevention portions <NUM> illustrated in <FIG> include plate-shaped flat portions <NUM> and fitting portions 4j having a shape similar to that of the fitting portions 4b. That is, the protruding portions <NUM> are disposed so as to extend from the second leg portions 42b to the come-out prevention portions <NUM>, and the opposed surfaces 4r are formed in a curved shape along the inner wall 12r so as to extend from the second leg portions 42b to the come-out prevention portions <NUM>.

Next, referring to <FIG>, the positional relationship between the slider <NUM> and body <NUM> will be described. In <FIG>, the boundaries between the members are shown by broken lines for convenience. As shown in <FIG>, left and right corners E located on the boundary between the operation portion <NUM> and pinching portion <NUM> extend linearly along the front-rear direction and are supported by the upper end of the opening <NUM>. The width of the slider <NUM> in the positions of the pair of protruding portions <NUM> is wider than the width (W<NUM>) of the opening <NUM>, and the contact ends F of the protruding portions <NUM> can contact the inner wall 12r. The contact ends F of the pair of protruding portions <NUM> extend linearly along the front-rear direction. That is, the slider <NUM> is shaped such that the pinching portion <NUM> between the operation portion <NUM> and protruding portions <NUM> is relatively recessed in a cross-sectional view. The positions of the side walls 15b of the opening <NUM> of the syringe <NUM> are constrained by the corners E and contact ends F of the slider <NUM> (two-line constraint). Thus, the opening <NUM> serves as a rail for causing the slider <NUM> to stably slide.

Next, referring to <FIG>, a series of operations related to injection using the injection device <NUM> will be described. To clearly show the operating state of the push-out mechanism, <FIG> illustrate the syringe <NUM> whose half is cut off. In these drawings, the portion into which the chemical solution C is charged is dotted so that the movement of the chemical solution C is clarified.

As with <FIG>, <FIG> shows the injection device <NUM> put in the initial state. <FIG> shows the injection device <NUM> put in a push-out state, which is a state in which the slider <NUM> is in contact with the button <NUM> disposed in the frontmost position in the opening <NUM>. In <FIG>, the button <NUM> is in contact with both the front wall 15c of the opening <NUM> and the push end surface 51c of the slider <NUM>. <FIG> shows the injection device <NUM> put in the stretched state. <FIG> shows the injection device <NUM> put in an injection completion state, which is a state in which the button <NUM> is pushed down in the stretched state of <FIG>.

When the slider <NUM> is slid in the tip direction in the injection device <NUM> put in the initial state (<FIG>), the conversion portion <NUM> and button <NUM> also slide in the tip direction. Then, as seen in the push-out state of <FIG>, the push-out mechanism stops moving with the button <NUM> contacting the front wall 15c of the opening <NUM>. In the transition from <FIG>, the gasket <NUM> moves in the tip direction along with the conversion portion <NUM> by the length Te (see <FIG>). That is, the user is able to remove air by operating the slider <NUM> so that the injection device <NUM> makes the transition from the initial state to the push-out state. Hereafter, the transition from the initial state to the push-out state is also referred to as "air removal.

In the injection device <NUM> put in the push-out state (<FIG>), the preset prescribed amount of chemical solution C remains in the chemical solution storage portion 12a. When the slider <NUM> is slid rearward in the injection device <NUM> put in the push-out state, the slider <NUM> alone moves rearward. When the slider <NUM> contacts the rear wall 15d of the opening <NUM>, it stops moving, as seen in the stretched state of <FIG>. At this time, the safety protrusion <NUM> is gradually removed from the pinching groove <NUM>.

In the injection device <NUM> put in the stretched state (<FIG>), the tip end surface 55c of the safety protrusion <NUM> is flush with the rear end surface 41d of the button <NUM>. Thus, the user is able to push down the button <NUM> along the tip end surface 55c of the safety protrusion <NUM>. After the safety protrusion <NUM> is removed from the pinching groove <NUM>, the position of the button <NUM> is maintained mainly by the static friction between the front slopes <NUM> and the rear slopes <NUM> of the conversion portion <NUM> and the static friction between the gasket <NUM> connected to the conversion portion <NUM> and the syringe <NUM>.

When the button <NUM> is pushed down in the injection device <NUM> in the stretched state, the movement in the push-down direction of the button <NUM> is converted into movement in the tip direction by the conversion portion <NUM> and the gasket <NUM> moves toward the front end of the body <NUM>. When the button <NUM> is pushed down to the maximum extent possible (by the stroke H) in the injection device <NUM> according to the first embodiment, the gasket <NUM> contacts the tip portion of the body <NUM> and the prescribed amount of chemical solution C is injected from the injection needle mounted on the cylinder tip portion <NUM> into the injection subject or the like, as shown in <FIG>.

Next, referring to <FIG> and <FIG>, the stroke H, the amount of movement L, the set angle θ, the inner diameter D (mm) of the body <NUM>, the diameter α (mm) of the protruding portions <NUM>, the width W (mm) of the button <NUM>, and the prescribed amount (dose) of chemical solution C, and the relationships therebetween will be described. The amount of movement L is the distance of movement in the tip direction of the gasket <NUM> when the button <NUM> is pushed down to the maximum extent possible. While the cross-sectional shape of the protruding portions <NUM> is approximately a circular shape herein, it is not limited to such a shape.

As is understood from <FIG>, the set angle θ, the stroke H, and the amount of movement L have a relationship of "tanθ=H/L". This is arranged as the following Formula (<NUM>) with respect to the set angle θ. [Formula <NUM>] <MAT>.

Assuming that the lengths of the components are those shown in <FIG>, the relationship between the lengths is represented as "(W/<NUM>+α/<NUM>)<NUM>+(H/<NUM>)<NUM>≈(D/<NUM>)<NUM>" on the basis of the Pythagorean theorem. This is arranged as the following Formula (<NUM>) with respect to the stroke H. Note that in Formula (<NUM>), the square root (√) of the entire "(D<NUM>-<NUM>(W/<NUM>+α/<NUM>)<NUM>)" is obtained. [Formula <NUM>] <MAT>.

The relationship between the dose V (mm<NUM>: µL), the inner diameter D, and the amount of movement L are represented as "V=π×(D/<NUM>)<NUM>×L". This is arranged as the following Formula (<NUM>) with respect to the amount of movement L. [Formula <NUM>] <MAT>.

It is preferable to adjust the settings of the above parameters in consideration of the sense of resistance when the button <NUM> is pushed down, the certainty of push-down of the button <NUM>, the amount of movement L, the dose V, or the like. As the set angle θ is increased, the resistance when the button <NUM> is pushed down is reduced. For this reason, as the set angle θ is increased, the user is able to inject the chemical solution C with a lighter touch. Note that when the set angle θ is increased excessively, the amount of movement L is reduced and thus the dose of the chemical solution C is reduced. In the first embodiment, the set angle θ is set in the range of, for example, <NUM>° to <NUM>°. However, the set angle θ may be arbitrarily adjusted to an angle inside or outside the above range in accordance with the size of the entire injection device, the dose of the chemical solution C, or the like. The same also applies to second and third embodiments.

As described above, the injection device <NUM> includes the conversion portion <NUM> contained in the body <NUM>, the button <NUM> supported by the conversion portion <NUM> with the side portions thereof sandwiched between the side walls 15b of the opening <NUM>, and the slider <NUM> for moving the conversion portion <NUM> and button <NUM> in the tip direction. The button <NUM> includes the pair of leg portions <NUM> having the front slopes <NUM>, and the conversion portion <NUM> includes the pair of engaging portions <NUM> having the rear slopes <NUM> that slidingly contact the front slopes <NUM> of the button <NUM>. Thus, the user is able to remove air by operating the slider <NUM> located on a side portion of the body <NUM> so that the conversion portion <NUM> is moved in the tip direction. The user is also able to inject the liquid to the injection subject by operating the button <NUM> located on a side portion of the body <NUM> so that the conversion portion <NUM> is further moved in the tip direction. This eliminates frequent switching of the injection device area to be held from the series of operations related to injection and reduces the load on the injection subject.

In the case of a conventional injection device, a predetermined force is required to push down a plunger. This and the needle position and the operation area being away from each other are more likely to cause an injection device shake. An injection device shake during injection may cause a shift in the position of the needle after the needle is punctured and may damage the punctured portion or its vicinity. In the case of the injection device <NUM>, the user only has to perform a simple operation of pushing down the button <NUM> and thus is able to move the conversion portion <NUM> connected to the gasket <NUM> in the tip direction and to inject the chemical solution C into the body of a human or animal, or the like. In the case of the injection device <NUM>, the user is able to push the button <NUM> using only the index finger. Thus, the user is able to support the injection device <NUM> using the remaining fingers and thus to operate the injection device <NUM> stably.

The button <NUM> according to the first embodiment has the pinching groove <NUM> formed along the tip direction from the rear end surface 41d. The slider <NUM> includes the safety protrusion <NUM> disposed on the button <NUM> side of the operation portion <NUM> and formed so as to be insertable into the pinching groove <NUM> of the button <NUM>. Thus, in a state in which the safety protrusion <NUM> is inserted in the pinching groove <NUM>, the user is prevented from pushing down the button <NUM>. Thus, before performing injection, for example, during air removal, misoperation such as push-down of the button <NUM> and thus ejection of the chemical solution C is prevented.

The pinching groove <NUM> according to the first embodiment is formed from the rear end surface 41d of the button <NUM> to the front end surface 41c. Thus, after the slider <NUM> moves rearward and the safety protrusion <NUM> is removed, the bottom 45u of the pinching groove <NUM> is opposed to the core portion <NUM>, that is, the core portion <NUM> becomes insertable into the pinching groove <NUM>. Thus, when a force is applied to the button <NUM> from above, the core portion <NUM> is inserted into the pinching groove <NUM>. This allows the user to push down the button <NUM>. That is, the pinching groove <NUM> prevents misoperation of the button <NUM>, as well as provides the stroke H, which is the distance by which the button <NUM> can be pushed down, between the pinching groove <NUM> and the core portion <NUM>.

The safety protrusion <NUM> is formed such that the tip end surface 55c becomes flush with the rear end surface 41d in a state in which the button <NUM> is in contact with the front wall 15c of the opening <NUM> and the slider <NUM> is in contact with the rear wall 15d of the opening <NUM>. Thus, when the button <NUM> is pushed down, the button <NUM> moves in the push-down direction with the rear end surface 41d contacting the tip end surface 55c of the safety protrusion <NUM>. At this time, the slider <NUM> is prevented from moving rearward by the rear wall 15d of the opening <NUM>. Thus, the button <NUM> is pushed down while being prevented from moving rearward by the safety protrusion <NUM>. Thus, the operation in the push-down direction of the button <NUM> is converted into operation in the tip direction of the conversion portion <NUM> as it is, and the user is able to surely inject the prescribed amount of chemical solution C charged into the chemical solution storage portion 12a into the human body or the like.

The slider <NUM> may include the operation portion <NUM> formed such that the width Ws becomes wider than the width (W<NUM>) of the opening <NUM>, the pinching portion <NUM> connected to the operation portion <NUM> and disposed between the side walls 15b of the opening <NUM>, and the auxiliary portion <NUM> connected to the pinching portion <NUM> and disposed inside the body <NUM>. The auxiliary portion <NUM> may include the pair of protruding portions <NUM> formed along the tip direction so as to contact the inner wall 12r of the body <NUM>. Thus, the side walls 15b of the opening <NUM> are sandwiched between both side end portions of the operation portion <NUM> and the pair of protruding portions <NUM> while being opposed to the pinching portion <NUM>. Thus, the opening <NUM> serves as a rail for causing the slider <NUM> to smoothly slide in the front-rear direction. The slider <NUM> is prevented from falling down from the syringe <NUM> by the pair of protruding portions <NUM>.

The auxiliary portion <NUM> may be formed such that a step is formed between the auxiliary portion <NUM> and the pinching portion <NUM> on the button <NUM> side. The pair of leg portions <NUM> may include the first leg portions 42a disposed on the gasket <NUM> side and the second leg portions 42b disposed on the slider <NUM> side. The button <NUM> may include the pair of come-out prevention portions <NUM> that extend rearward from lower portions of the second leg portions 42b and are to be engaged with the bottom portion 52b of the pinching portion <NUM>. Fall-down of the slider <NUM> is suppressed by the pair of protruding portions <NUM>, and the button <NUM> put in the initial state and the push-out state is disposed such that the come-out prevention portions <NUM> are opposed to the bottom portion 52b of the pinching portion <NUM>. Thus, fall-down of the button <NUM> is more surely prevented.

The opening <NUM> becomes wider in the tip direction from the position of the rear end surface 41d of the button <NUM> in contact with the front wall 15c. That is, the steps <NUM> are formed in positions of the rear end surface 41d of the button <NUM> in contact with the front wall 15c on the side walls 15b of the opening <NUM>. Thus, when the button <NUM> moves in the tip direction in accordance with an operation on the slider <NUM>, it moves from a narrower portion (width W<NUM>) to a wider portion (width W<NUM>) of the opening <NUM>. The button <NUM> that has entered the region having the width W<NUM> is prevented from moving rearward by the steps <NUM>, which are narrower rearward. Thus, when the user contacts the button <NUM> with the front wall 15c and then moves the slider <NUM> rearward, the user is able to avoid a situation in which the button <NUM> moves rearward in conjunction with the movement of the slider <NUM>.

The pair of leg portions <NUM> each include the base portions 4a extending from the side walls 41b. The base portions 4a may have the depressions <NUM> in the tip direction-side positions thereof adjacent to the side walls 15b of the opening <NUM>. Since the front-side resistance of the base portions 4a is reduced by the depressions <NUM>, the button <NUM> smoothly moves in the tip direction. Also, the rear-side resistance of the base portions 4a is relatively increased due to the presence of the depressions <NUM>. This suppresses rearward movement of the button <NUM>.

The pair of leg portions <NUM> may each include the base portions 4a extending from the side walls 41b and the fitting portions 4b extending from the base portions 4a. The fitting portions 4b have a curved shape in which the opposed surfaces 4r disposed so as to be opposed to the inner wall 12r of the body are along the inner wall 12r of the body <NUM>. This shape provides a longer core <NUM>-side length to the fitting portions 4b. Thus, in a state in which the button <NUM> has yet to be pushed down, the pair of leg portions <NUM> and the core portion <NUM> overlap each other over a greater range. Thus, the placement stability of the button <NUM> is increased. Also, the fitting portions 4b are tapered inwardly and have a predetermined length in the up-down direction on the core portion <NUM> side, as shown in <FIG>. However, the shape of the opposed surfaces 4r is along the inner wall 12r. Thus, the maximum stroke H is ensured while maintaining placement stability.

Referring to <FIG>, an injection device 100A according to a modification A of the first embodiment will be described. Components similar to those of the injection device <NUM> are given the same reference signs, and the description thereof will be omitted or simplified. In the injection device 100A according to the modification A, the pair of leg portions <NUM> of a button 40A have front slopes <NUM> inclined with respect to the tip direction by a set angle θ and rear auxiliary slopes 4t inclined with respect to the tip direction by the set angle θ. Thus, the leg portions <NUM> have a parallelogram shape in a side view. The front slopes <NUM> are disposed on the front side of the leg portions <NUM>, and the rear auxiliary slopes 4t are disposed on the rear side of the leg portions <NUM>.

Also, in the injection device 100A, the pair of engaging portions <NUM> of a conversion portion 30A each include a first engaging portion 34a and a second engaging portion 34b. The first engaging portion 34a has a rear slope <NUM> that slidingly contacts the front slope <NUM> of one leg portion <NUM>. The second engaging portion 34b according to the modification A has a front auxiliary slope 3t that slidingly contacts the rear auxiliary slopes 4t of the leg portion <NUM>.

The other configurations of the conversion portion 30A and button 40A are similar to those of the conversion portion <NUM> and button <NUM> described above. The syringe <NUM>, gasket <NUM>, and slider <NUM> of the injection device 100A are similar to those of the injection device <NUM>. The configurations and alternative configurations of the injection device <NUM> can be applied to the injection device 100A.

By configuring an injection device such that the leg portions <NUM> of the button 40A are sandwiched between the first engaging portions 34a and second engaging portions 34b of the conversion portion 30A, as seen in the injection device 100A, the button 40A is stably supported even if each leg portion <NUM> is not divided into two portions, that is, a front portion and a rear portion. That is, in the injection device 100A, the leg portions <NUM> of the button 40A slide in groovy portions between the first engaging portions 34a and second engaging portions 34b. That is, the first engaging portions 34a and second engaging portions 34b serve as rails for guiding the leg portions <NUM> when the user pushes down the button 40A. Thus, the user is able to smoothly and stably operate the button 40A. Other advantageous effects and the like are similar to those of the injection device <NUM>.

Referring to <FIG>, the configuration of the button 40B of an injection device <NUM> according to a modification B of the first embodiment will be described. The syringe <NUM>, gasket <NUM>, conversion portion <NUM>, and slider <NUM> of the injection device <NUM> according to the modification B are similar to those of the above injection device <NUM>. Note that the conversion portion <NUM> is required to have front auxiliary slopes 3t inclined with respect to the tip direction by a set angle θ, as shown in an example in <FIG>. Components similar to the above button <NUM> and button 40A are given the same reference signs, and the description thereof will be omitted or simplified.

In the button 40B of the injection device <NUM> according to the modification B, the first leg portions 42a of a pair of leg portions <NUM> have front slopes <NUM> that slidingly contact the rear slopes <NUM> of the conversion portion <NUM> and rear auxiliary slopes 4t that slidingly contact the front auxiliary slopes 3t (see <FIG>) of the conversion portion <NUM>. That is, the first leg portions 42a have a parallelogram shape in a side view. Thus, both sides of the first leg portions 42a of the button 40B are sandwiched between the first engaging portions 34a and second engaging portions 34b of the conversion portion <NUM>. Thus, the button 40B is stably supported by the conversion portion <NUM>. Thus, the operation stability of the button 40B is increased. Other advantageous effects and the like are similar to those of the injection device <NUM> according to the first embodiment and the injection device 100A according to the modification A.

Referring to <FIG>, the configuration of the button 40C of an injection device <NUM> according to a modification C of the first embodiment will be described. The syringe <NUM>, gasket <NUM>, conversion portion <NUM>, and slider <NUM> of the injection device <NUM> according to the modification C are similar to those of the above injection devices <NUM>. Components similar to the buttons <NUM>, 40A, and 40B are given the same reference signs, and the description thereof will be omitted or simplified.

In the case of the button 40C according to the modification C, the length Vb in the push-down direction of the rear end surface 41d is shorter than the length Va in the push-down direction of the front end surface 41c. A face wall 41a has a downward curved shape. Thus, a user is able to push down the button 40C with a natural touch even if the user does not consciously vertically push the button 40C. That is, the user is able to smoothly and easily operate the button 40C. It is preferable to set the difference between the length Va and the length Vb in accordance with the size of the entire injection device <NUM>, the stroke H, the amount of movement L, or the like. While <FIG> shows an example in which the face wall 41a is formed so as to be downward curved, this example is not limiting. For example, the face wall 41a may have a shape having a recessed central portion, or may be a flat slope. The configuration of the button 40C according to the modification C may be applied to the button 40A according to the modification A, or may be applied to the button 40B according to the modification B.

Referring to <FIG>, an example configuration of an injection device <NUM> according to a second embodiment will be described. To clearly show the operating state of a push-out mechanism, <FIG> and <FIG> illustrate a syringe <NUM> whose half is cut off. In these drawings, the area into which a chemical solution C is charged is dotted so that the movement of the chemical solution C is clarified. Components similar to those of the first embodiment are given the same reference signs, and the description thereof will be omitted or simplified.

<FIG> is a drawing illustrating the initial state of the injection device <NUM>. As shown in <FIG>, the injection device <NUM> includes the syringe <NUM>, a gasket <NUM>, a conversion portion <NUM>, a button <NUM>, and a slider <NUM>. The slider <NUM> includes a first slider <NUM> disposed one the button <NUM> side and a second slider <NUM> disposed near the rear wall 15d of an opening <NUM>. The initial state shown in <FIG> is a state in which the second slider <NUM> is in contact with the rear wall 15d of the opening <NUM> and the button <NUM> is in contact with the push end surface 51c of the first slider <NUM>. The button <NUM> in the drawings has a configuration similar to that of the button 40B according to the modification B, and the length Vb in the push-down direction of the rear end surface 41d is longer than the length Va in the push-down direction of the front end surface 41c. The button <NUM> is not limited to the example configuration in the drawings and may have a configuration similar to those of the buttons <NUM> and 40A to 40C disclosed in the first embodiment.

The first slider <NUM> includes a first body 160A having a communication hole <NUM> (see <FIG>) extending from the push end surface 51c, which is a front end surface, to a rear end surface 60d. The first body 160A includes a first operation portion <NUM> having a wider width than the width (W<NUM>) of the opening <NUM>, and a first sandwiched portion <NUM> disposed between both side walls 15b of the opening <NUM>, and a first auxiliary portion <NUM> disposed inside a body <NUM>. The first auxiliary portion <NUM> includes a pair of protruding portions <NUM> formed along the tip direction so as to contact the inner wall 12r of the body <NUM>. The shape of the protruding portions <NUM> is similar to that of the protruding portions <NUM> according to the first embodiment.

The first slider <NUM> includes a limitation protrusion <NUM> extending in the tip direction from the first body 160A and formed so as to be insertable into the pinching groove <NUM> of the button <NUM>. The first auxiliary portion <NUM> illustrated in the drawings includes a pair of auxiliary protrusions <NUM> formed so as to correspond to the pair of come-out prevention portions <NUM> of the button <NUM> and extending forward from lower portions of the first auxiliary portion <NUM>. The tip end surface 65c of the limitation protrusion <NUM> is flush with the rear end surface 41d of the button <NUM> in a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the first slider <NUM> and second slider <NUM> are disposed in the rearmost position in the opening <NUM> (see <FIG> and <FIG>). The limitation protrusion <NUM> illustrated in the drawings is connected to the first operation portion <NUM> and first sandwiched portion <NUM>.

The second slider <NUM> includes a second body 170A disposed outside the body <NUM> and including a second operation portion <NUM> formed so as to have a wider width than the width (W<NUM>) of the opening <NUM>. The second body 170A includes a second sandwiched portion <NUM> disposed between the side walls 15b of the opening <NUM> and a second auxiliary portion <NUM> disposed inside the body <NUM>. The second auxiliary portion <NUM> includes a pair of protruding portions <NUM> formed along the tip direction so as to contact the inner wall 12r of the body <NUM>. The shape of the protruding portions <NUM> is similar to that of the protruding portions <NUM> according to the first embodiment.

The second slider <NUM> includes a safety protrusion <NUM> disposed on the button <NUM> side of the second operation portion <NUM> and formed so as to be insertable into the communication hole <NUM> and pinching groove <NUM>. The tip portion 75n of the safety protrusion <NUM> is disposed on the limitation protrusion <NUM> in a state in which the second slider <NUM> is in contact with the rear end surface 60d of the first slider <NUM> (see <FIG> and <FIG>). The tip end surface 75c of the limitation protrusion <NUM> is flush with the rear end surface 41d of the button <NUM> in a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the second slider <NUM> are disposed in the rearmost position in the opening <NUM> (see <FIG>).

Hereafter, referring to <FIG> and <FIG>, the specific configuration of the first slider <NUM> and second slider <NUM> will be further described. <FIG> shows a contact state, which is a state in which the safety protrusion <NUM> is inserted in the communication hole <NUM> and the rear end surface 60d of the first slider <NUM> and the contact end surface 70c of the second slider <NUM> are in contact with each other. The contact end surface 70c is the front end surface of the second body 170A.

As shown in <FIG>, the safety protrusion <NUM> includes a base portion <NUM> extending forward from the contact end surface 70c of the second body 170A and the tip portion 75n extending forward from the base portion <NUM>. In the contact state, the tip portion 75n is disposed on the limitation protrusion <NUM>. As illustrated in <FIG>, in the contact state, the tip end surface 75c of the tip portion 75n according to the second embodiment is flush with the tip end surface 65c of the limitation protrusion <NUM>.

The height Hn of the tip portion 75n is set in accordance with a preset initial action dose. The initial action dose is set in accordance with the type of the chemical solution C, or the like and can be changed as necessary. In the second embodiment, the auxiliary protrusions 63t of the first slider <NUM> are formed such that the distance Z from the lower ends of the come-out prevention portions <NUM> to the auxiliary protrusions 63t (see <FIG>, <FIG>, and <FIG>) becomes equal to the height Hn of the tip portion 75n in the initial state or the like. It is preferable to set the height Hc of the limitation protrusion <NUM> in consideration of the operation stability of the button <NUM>.

Next, referring to <FIG> and <FIG>, a series of operations related to injection using the injection device <NUM> will be described. <FIG> shows the injection device <NUM> put in the push-out state. The push-out state is a state in which the button <NUM> disposed in the frontmost position in the opening <NUM> is in contact with the push end surface 51c of the slider <NUM> put in the contact state. <FIG> shows the injection device <NUM> put in a first stretched state. The first stretched state is a state in which the button <NUM> disposed in the frontmost position in the opening <NUM> is in contact with the push end surface 51c of the slider <NUM> put in a separated state. The separated state of the slider <NUM> is a state in which the rear end surface 60d and the contact end surface 70c are not in contact with each other and the push end surface 51c of the first slider <NUM> and the tip end surface 75c of the safety protrusion <NUM> are flush with each other. <FIG> shows the injection device <NUM> put in a first push-down state, which is a state in which the button <NUM> is pushed down in the first stretched state. <FIG> shows the injection device <NUM> put in a second stretched state. The second stretched state is a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the slider <NUM> put in the contact state is disposed in the rearmost position in the opening <NUM>. In the second embodiment, the rearmost position in the opening <NUM> of the slider <NUM> put in the contact state is the position in which the rear end surface 70d of the second slider <NUM> is in contact with the rear wall 15d. <FIG> shows the injection device <NUM> in a second push-down state, which is a state in which the button <NUM> is pushed down in the second stretched state.

In the push-out state shown in <FIG>, the button <NUM> is in contact with the front wall 15c of the opening <NUM>. A user is able to remove air by operating the slider <NUM> so that the injection device <NUM> makes transition from the initial state to the push-out state. When the user slides the second slider <NUM> rearward in the injection device <NUM> put in the push-out state, the tip portion 75n of the safety protrusion <NUM> is gradually removed from the pinching groove <NUM>. As seen in the first stretched state shown in <FIG>, when the second slider <NUM> contacts the rear wall 15d, the tip portion 75n is completely removed from the pinching groove <NUM>.

As seen above, in the injection device <NUM> put in the first stretched state, there is a gap having a width corresponding to the height Hn of the tip portion 75n between the bottom 45u of the pinching groove <NUM> and the limitation protrusion <NUM> of the first slider <NUM>. Thus, the user is able to push down the button <NUM> along the push end surface 51c until the bottom 45u contacts the limitation protrusion <NUM> and to put the injection device <NUM> into the first push-down state shown in <FIG>. When the button <NUM> is pushed down by the height Hn, the gasket <NUM> moves toward the tip of the body <NUM> by "Hn/tanθ. " In an example in <FIG>, the lower ends of the come-out prevention portions <NUM> are in contact with the upper ends of the auxiliary protrusions 63t. That is, in the first stretched state of the injection device <NUM>, the auxiliary protrusions 63t serve as auxiliary limiters to the push-down operation of the button <NUM>.

When the user slides the first slider <NUM> rearward in the injection device <NUM> put in the first push-down state, the limitation protrusion <NUM> is gradually removed from the pinching groove <NUM> and the area in which the upper ends of the auxiliary protrusions 63t and the lower ends of the come-out prevention portions <NUM> are opposed to each other is gradually reduced. As seen in the second stretched state shown in <FIG>, when the first slider <NUM> contacts the second slider <NUM>, the limitation protrusion <NUM> is completely removed from the pinching groove <NUM> and the come-out prevention portions <NUM> and auxiliary protrusions 63t are no longer opposed to each other.

In the injection device <NUM> put in the second stretched state, the tip end surface 65c of the limitation protrusion <NUM> is flush with the rear end surface 41d of the button <NUM>. Thus, the user is able to move the button <NUM> along the tip end surface 65c in the push-down direction and to put the injection device <NUM> into the second push-down state shown in <FIG>. In the second stretched state of the injection device <NUM>, the tip end surface 75c of the tip portion 75n is flush with the rear end surface 41d of the button <NUM>. Thus, the user is able to more stably push down the button <NUM>. The user is able to push down the button <NUM> by the stroke H by performing the operation related to the transition from the first stretched state to the first push-down state and the operation related to the transition from the second stretched state to the second push-down state. That is, by using the injection device <NUM>, the user is able to inject the prescribed amount of chemical solution C into an injection subject or the like in two stages.

As shown in <FIG>, the injection device <NUM> put in the second stretched state may be configured such that the rear ends of the come-out prevention portions <NUM> and the front ends of the auxiliary protrusions 63t are flush with each other. Thus, the area in which the button <NUM> and slider <NUM> contact each other is increased, and the button <NUM> is supported also from below. Thus, the stability of the button <NUM> during operation is further increased.

As described above, the injection device <NUM> includes the conversion portion <NUM> contained in the body <NUM>, the button <NUM> supported by the conversion portion <NUM> with the side portions thereof sandwiched between the side walls 15b of the opening <NUM>, and the slider <NUM> for moving the conversion portion <NUM> and button <NUM> in the tip direction. Thus, the user is able to remove air by operating the slider <NUM> located on a side portion of the body <NUM>. The user is also able to inject the liquid to the injection subject by operating the button <NUM> located on a side portion of the body <NUM> so that the conversion portion <NUM> is further moved in the tip direction. This eliminates frequent switching of the injection device area to be held from the series of operations related to injection and reduces the load on the injection subject.

The slider <NUM> according to the second embodiment includes the first slider <NUM> and second slider <NUM>. The first slider <NUM> includes the first body 160A having the communication hole <NUM> and the limitation protrusion <NUM> formed so as to be insertable into the pinching groove <NUM>. The second slider <NUM> includes the safety protrusion <NUM> formed so as to be insertable into the communication hole <NUM> and pinching groove <NUM>. The tip portion 75n of the safety protrusion <NUM> is disposed on the limitation protrusion <NUM> in a state in which the second slider <NUM> is in contact with the rear end surface 60d of the first slider <NUM>. Thus, as seen in the initial state (<FIG>) and push-out state (<FIG>), in a state in which the tip portion 75n is inserted in the pinching groove <NUM>, the user is prevented from pushing down the button <NUM>. Thus, before performing injection, for example, during air removal, misoperation such as push-down of the button <NUM> and thus ejection of the chemical solution C is prevented.

The safety protrusion <NUM> is formed such that the tip end surface 75c is flush with the rear end surface 41d of the button <NUM> in a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the second slider <NUM> are disposed in the rearmost position in the opening <NUM> (see <FIG>). That is, in the injection device <NUM> put in the first stretched state (<FIG>), the limitation protrusion <NUM> is inserted in the pinching groove <NUM>, and the tip portion 75n is removed from the pinching groove <NUM>. Thus, the injection device <NUM> put in the first stretched state allows the limitation protrusion <NUM> to serve as a limiter to the push-down operation of the button <NUM> and is able to eject the chemical solution in the initial action dose corresponding to the height Hn of the tip portion 75n.

The limitation protrusion <NUM> is formed such that the tip end surface 65c is flush with the rear end surface 41d of the button <NUM> in a state in which the button <NUM> is disposed in the frontmost position in the opening <NUM> and the first slider <NUM> and second slider <NUM> (the slider <NUM> put in the contact state) are disposed in the rearmost position in the opening <NUM>. That is, in the injection device <NUM> put in the second stretched state (<FIG>), the rear end surface 41d of the button <NUM> is in contact with the tip end surface 65c of the limitation protrusion <NUM>. Also, in the injection device <NUM> put in the second stretched state, rearward movement of the first slider <NUM> is blocked by the rear wall 15d of the opening <NUM> through the second slider <NUM>. Thus, the user is able to move the button <NUM> in the push-down direction along the tip end surface 65c.

As described above, the injection device <NUM> is configured to be able to eject the prescribed amount of chemical solution C in two stages. Thus, the user is able to inject the initial action dose of chemical solution C to the injection subject by pushing down the button <NUM> in the injection device <NUM> put in the first stretched state, to check the condition of the injection subject, and then to determine whether to inject the remaining chemical solution C. Thus, by using the injection device <NUM>, the user is able to flexibly administer the chemical solution in accordance with the physical condition of the injection subject, or the like. That is, by using the injection device <NUM>, the user is able to administer the chemical solution in two stages, for example, by injecting <NUM>µL of chemical solution C to the injection subject, then checking the stability of the condition of the injection subject, and then additionally injecting <NUM>µL of chemical solution C. Other advantageous effects and the like are similar to those of the first embodiment. The configurations and alternative configurations of the injection device <NUM> according to the first embodiment can be applied to the injection device <NUM>, and the configurations of the modifications A to C can also be applied thereto.

The position in the tip direction of the front wall 15c of the opening <NUM> is set on the basis of the position of the gasket <NUM> with the front end surface 41c of the button <NUM> contacting the front wall 15c, that is, the prescribed amount of chemical solution C. However, the prescribed amount of the chemical solution C is not necessarily constant. For this reason, if the position of the front wall 15c is fixed, it is necessary to produce injection devices for each prescribed amount. For this reason, an adjustment mechanism that can change the range of motion of the buttons <NUM> and 40A to 40C may be provided on the front wall 15c or its vicinity of the syringe <NUM> of the injection devices according to the first and second embodiments. The adjustment mechanism allows the user to adjust the position corresponding to the front wall 15c of the opening <NUM> in the front-rear direction.

The adjustment mechanism may be configured to be able to make stepwise adjustments corresponding to multiple doses, for example, may be configured to be able to set any dose in a sliding manner. The injection device <NUM> including the adjustment mechanism makes the position of the buttons <NUM> and 40A to 40C at the time of push-down variable and makes the position of the front wall 15c substantially adjustable. That is, by providing an allowance to the amount of movement L corresponding to the stroke H, the dose of the chemical solution C becomes adjustable.

Referring to <FIG>, an example configuration of an injection unit <NUM> according to a third embodiment will be described. Components similar to those of the first and second embodiment are given the same reference signs, and the description thereof will be omitted or simplified. The injection unit <NUM> illustrated in these drawings includes an injection device <NUM> and an adjustment unit <NUM> configured to adjust the amount of chemical solution C to be ejected from the injection device <NUM>. The injection device <NUM> includes a syringe <NUM>, a gasket <NUM>, a conversion portion <NUM>, a button <NUM>, and a slider <NUM>. Although the syringe <NUM> is made of a transparent resin or the like, the internal components and the like are shown in <FIG> and <FIG> in a non-transparent manner for convenience.

The adjustment unit <NUM> illustrated in the drawings includes two adjustment members. One adjustment member is referred to as a first adjustment member <NUM>, and the other adjustment member as a second adjustment member <NUM>. As shown in <FIG>, the first adjustment member <NUM> includes a frame member 121u having a U-shaped cross-section and a spacer 121w disposed between both side walls 15b of an opening <NUM>. The second adjustment member <NUM> includes a frame member 122u having a U-shaped cross-section and a spacer 122w disposed between the side walls 15b of the opening <NUM>.

The frame member 121u and frame member 122u are formed so as to be along the periphery of the body <NUM> and are able to pinch the body <NUM>. The spacer 121w is disposed in the central location along the curved direction of the frame member 121u on the inner surface of the frame member 121u. As shown in <FIG>, the spacer 121w is a plate-shaped member having a width P formed on one end along the tip direction on the inner surface of the frame member 121u. The inner surface of the frame member 121u is a surface oriented toward the body <NUM> of the frame member 121u. The spacer 122w is disposed in the central location along the curved direction of the frame member 121u on the inner surface of the frame member 122u. As shown in <FIG>, the spacer 122w is a plate-shaped member having a width Q formed on one end along the tip direction on the inner surface of the frame member 122u. The inner surface of the frame member 122u is a surface oriented toward the body <NUM> of the frame member 122u. The width P of the spacer 121w is narrower than the width Q of the spacer 122w. The width P and width Q are factors that determine the stepwise amounts of adjustment in the administration of the chemical solution, and can be set arbitrarily and changed. Hereafter, the spacer 121w and spacer 122w may be collectively referred to as spacers <NUM> without distinguishing them from each other.

As shown by broken lines in <FIG>, the first adjustment member <NUM> and second adjustment member <NUM> can be mounted in a position adjacent to the front wall 15c or a position adjacent to the rear wall 15d of the body <NUM> with the spacers <NUM> put in the opening <NUM>. When mounting the first adjustment member <NUM> adjacent to the front wall 15c, the first adjustment member <NUM> is disposed such that the spacer 121w is located on the rear side. When mounting the first adjustment member <NUM> adjacent to the rear wall 15d, the first adjustment member <NUM> is disposed such that the spacer 121w is located on the front side. For this reason, when mounting both the first adjustment member <NUM> and second adjustment member <NUM> adjacent to the front wall 15c, the first adjustment member <NUM> is disposed in a more front position than that of the second adjustment member <NUM>. When mounting both the first adjustment member <NUM> and second adjustment member <NUM> adjacent to the rear wall 15d, the first adjustment member <NUM> is disposed in a more rear position than that of the second adjustment member <NUM>.

As shown in <FIG>, the syringe <NUM> has a configuration similar to that of the syringe <NUM> according to the first embodiment. Note that the length T<NUM> of the opening <NUM> of the syringe <NUM> is longer than the length T<NUM> of the opening <NUM> of the syringe <NUM> in <FIG> by the sum of the widths of the spacers <NUM> of the adjustment unit <NUM>, that is, the sum of the width P and width Q (T<NUM>=T<NUM>+P+Q). The sum of the widths of the spacers <NUM> of the adjustment unit <NUM> is the sum of the widths of the spacers <NUM> of all the adjustment members of the adjustment unit <NUM> and is hereafter referred to as the "sum of the widths of the spacers <NUM>. " That is, the length T<NUM> is longer than the length from the front end surface 41c of the button <NUM> to the rear end surface 51d of the slider <NUM> by the sum of the widths of the spacers <NUM> in a state in which the rear end surface 41d of the button <NUM> and the tip end surface 55c of the safety protrusion <NUM> are flush with each other. Also, the length T<NUM> from the front wall 15c to the steps <NUM> is longer than the length T<NUM> of the syringe <NUM> by the sum of the widths of the spacers <NUM> of the adjustment unit <NUM>.

In the third embodiment, when the adjustment unit <NUM> is mounted adjacent to the front wall 15c, the frontmost position in the opening <NUM> of the button <NUM> is a position in contact with the adjustment unit <NUM>. Similarly, when the adjustment unit <NUM> is mounted adjacent to the rear wall 15d, the rearmost position in the opening <NUM> of the slider <NUM> is a position in contact with the adjustment unit <NUM>.

Next, referring to <FIG>, a method of adjusting the dose of the chemical solution C by selectively using the adjustment members forming the adjustment unit <NUM> will be described. The adjustment unit <NUM> according to the third embodiment includes the two adjustment members including the spacers <NUM> having different widths. Thus, the dose of the chemical solution C can be adjusted in four stages. For example, as shown in <FIG>, the initial state of the injection unit <NUM> is set to a state in which the button <NUM> and slider <NUM> are disposed in the rearmost position in the opening <NUM> and the adjustment unit <NUM> is mounted adjacent to the front wall 15c of the opening <NUM>. By mounting the adjustment members adjacent to the front wall 15c, movement in the tip direction of the button <NUM> is blocked by the spacers <NUM> thereof during air removal. The gasket <NUM> moves in conjunction with movement in the tip direction of the button <NUM> during air removal. For this reason, by mounting more adjustment members adjacent to the front wall 15c, a larger amount of chemical solution C can be left in the chemical solution storage portion 12a after air removal. Thus, the amount of chemical solution C that can be administered is reduced in stages in the order of <FIG>, <FIG>, <FIG>, and <FIG>.

Hereafter, a method for adjusting the dose of the chemical solution C will be described assuming that the injection device <NUM> is put in the initial state illustrated in <FIG>. <FIG> illustrate the injection device <NUM> put in the stretched state, and the other states are omitted. The stretched state is a state in which the button <NUM> is located in the placeable frontmost position in the opening <NUM> and the slider <NUM> is located in the placeable rearmost position in the opening <NUM>. In the stretched state, the tip end surface 55c of the safety protrusion <NUM> is flush with the rear end surface 41d. <FIG> schematically show the components and illustrate the syringe <NUM> whose half is cut off. It is assumed that the amount of movement L corresponding to the stroke H has been adjusted in accordance with a state in which the first adjustment member <NUM> and second adjustment member <NUM> are mounted adjacent to the front wall 15c.

<FIG> corresponds to a case in which the largest amount of chemical solution C is administered from the injection unit <NUM>. In this case, there is no need to demount the adjustment unit <NUM> mounted adjacent to the front wall 15c. Thus, the user is able to remove air (S11), then to put the injection unit <NUM> into the stretched state by sliding the slider <NUM> rearward (S12: the state in <FIG>), and to inject the chemical solution C corresponding to the amount of movement L to the injection subject or the like by pushing down the button <NUM> by the stroke H (S13).

<FIG> corresponds to a case in which the second largest amount of chemical solution C, that is, a second amount of chemical solution C is administered from the injection unit <NUM>. In this case, first, the user demounts the first adjustment member <NUM> mounted adjacent to the front wall 15c (S21) and removes air (S22). At this time, the gasket <NUM> moves forward from the position in <FIG> by the width P. Then, the user mounts the first adjustment member <NUM> adjacent to the rear wall 15d (S23) and puts the injection unit <NUM> into the stretched state by sliding the slider <NUM> rearward (S24: the state in <FIG>). Then, the user injects the chemical solution C corresponding to the amount of movement "L-P" of the gasket <NUM> to the injection subject or the like by pushing down the button <NUM> to the greatest extent possible (S25).

<FIG> corresponds to a case in which the third largest amount of chemical solution C, that is, a third amount of chemical solution C is administered from the injection unit <NUM>. In this case, first, the user demounts the second adjustment member <NUM> mounted adjacent to the front wall 15c (S31) and removes air (S32). At this time, the gasket <NUM> moves forward from the position in <FIG> by the width Q. Then, the user mounts the second adjustment member <NUM> adjacent to the rear wall 15d (S23) and puts the injection unit <NUM> into the stretched state by sliding the slider <NUM> rearward (S34: the state in <FIG>). Then, the user injects the chemical solution C corresponding to the amount of movement "L-Q" of the gasket <NUM> to the injection subject or the like by pushing down the button <NUM> to the greatest extent possible (S35).

<FIG> corresponds to a case in which the smallest amount of chemical solution C is administered from the injection unit <NUM>. In this case, first, the user demounts the first adjustment member <NUM> and second adjustment member <NUM> mounted adjacent to the front wall 15c (S41) and removes air (S42). At this time, the gasket <NUM> moves forward from the position in <FIG> by the width "P+Q". Then, the user mounts the first adjustment member <NUM> and second adjustment member <NUM> adjacent to the rear wall 15d (S43) and puts the injection unit <NUM> into the stretched state by sliding the slider <NUM> rearward (S44: the state in <FIG>). Then, the user injects the chemical solution C corresponding to the amount of movement "L-(P+Q)" of the gasket <NUM> to the injection subject or the like by pushing down the button <NUM> to the greatest extent possible (S45).

For example, it is assumed that a dose of <NUM>µL corresponds to the amount of movement L of the gasket <NUM>, a dose of <NUM>µL corresponds to the movement of the gasket <NUM> of <NUM>, the width P is <NUM>, and the width Q is <NUM>. Thus, in the case of <FIG>, <NUM>µL of chemical solution C is administered; in the case of <FIG>, <NUM>µL of chemical solution C is administered; in the case of <FIG>, <FIG> µL of chemical solution C is administered; and in the case of <FIG>, <FIG> µL of chemical solution C is administered. The largest amount, the second amount, the third amount, and the smallest amount can be changed arbitrarily by adjusting the amount of movement L corresponding to the stroke H or the width P and width Q, and/or in accordance with the size of the syringe <NUM> to be employed, or the like.

While the example in which the injection unit <NUM> includes the injection device <NUM> having a configuration similar to that of the injection device <NUM> has been described above, this example is not limiting. The injection device <NUM> may have a configuration similar to that of the injection device 100A, <NUM>, <NUM>, or <NUM>. That is, the configuration of the third embodiment can be applied to the configuration of any of the first and second embodiments by adjusting the length of the opening <NUM> on the basis of the sum of the widths of the spacers <NUM> of the adjustment unit <NUM>.

As with the second adjustment member <NUM>, the first adjustment member <NUM> may be formed such that the width of the frame member 121u and the width of the spacer 121w are similar. Thus, when disposing the first adjustment member <NUM> and second adjustment member <NUM> in a stacked manner (<FIG>, <FIG>, <FIG>, <FIG>), any of these members may be disposed in a more front or more rear position than the position of the other member. While the spacers <NUM> having a shape in which they are sandwiched between the side walls 15b of the opening <NUM>, that is, a shape in which they can be fitted between the side walls 15b are illustrated in the drawings, this shape is not limiting. The spacers <NUM> may take various shapes to the extent that they can block forward movement of the button <NUM> in the opening <NUM>.

As described above, the injection unit <NUM> includes the injection device <NUM> and the adjustment unit <NUM> including the first adjustment member <NUM> and second adjustment member <NUM>. The first adjustment member <NUM> and second adjustment member <NUM> include the spacers <NUM> having the predetermined widths and disposed between the side walls 15b of the opening <NUM>. The width P of the spacer 121w of the first adjustment member <NUM> and the width Q of the spacer 122w of the second adjustment member <NUM> are set to different lengths. Thus, the user is able to adjust the dose of the chemical solution C in four stages and thus to, for example, adjust the dose for each injection subject or adjust the dose in accordance with the physical condition, vital signs, or the like of the injection subject.

The adjustment unit <NUM> may consist of one adjustment member. The injection unit <NUM> thus configured allows the user to adjust the dose of the chemical solution C in two stages. The adjustment unit <NUM> may include three or more adjustment members including spacers <NUM> having different widths. The injection unit <NUM> thus configured allows the user to adjust the dose of the chemical solution C in <NUM>n stages (n is the number of adjustment members).

The above embodiments are specific examples of a side push down-type injection device and injection unit, and the technical scope of the present invention is not limited to these aspects. For example, in the injection devices <NUM>, 100A, <NUM>, and <NUM> (hereafter, the reference signs are omitted) according to the embodiments, the tip-side shape of the syringes <NUM> and <NUM> is not limited to the examples in the drawings and can be changed as necessary. It is preferable to adjust the shape of the front end portion <NUM> of the gasket <NUM> in accordance with the tip-side shape of the syringe <NUM> or <NUM>. The shape or the like of the lid portion <NUM> is not limited to the examples in the drawings and can be changed as necessary. Note that the injection device may has a configuration without the lid portion <NUM>. The syringes <NUM> and <NUM> according to the embodiments need not have the steps <NUM> on the opening <NUM>, or need not be formed such that the width W<NUM> near the rear wall 15d of the opening <NUM> becomes relatively narrow. That is, with respect to the syringes <NUM> and <NUM>, the width of the opening <NUM> may be uniform over the entire area along the tip direction, or the steps <NUM> may simply be disposed, or only the width W<NUM> near the rear wall 15d may differ from the width of the other portions. For example, when the width near the front wall 15c of the opening <NUM> and the width near the rear wall 15d thereof differ from each other, the adjustment unit <NUM> may include an adjustment member to be mounted adjacent to the front wall 15c and an adjustment member to be mounted adjacent to the rear wall 15d.

While the examples in which the pair of leg portions <NUM> of the buttons <NUM>, 40B, and 40C include the first leg portions 42a and second leg portions 42b have been described above, these examples are not limiting. That is, the leg portions <NUM> may consist of only the first leg portions 42a or may consist of only the second leg portions 42b. If the leg portions <NUM> consist of only the first leg portions 42a, the engaging portions <NUM> of the conversion portion <NUM> may consist of only the first engaging portion 34a. If the leg portions <NUM> consist of only the second leg portions 42b, the engaging portions <NUM> of the conversion portion <NUM> may consist of only the second engaging portion 34b. However, the leg portions <NUM> preferably include the first leg portions 42a and second leg portions 42b in terms of the placement stability of the button <NUM>, the stability thereof during push-down, or the like.

While the buttons <NUM>, 40B, and 40C including the first leg portions 42a and second leg portions 42b having the depressions <NUM> have been described in the first to third embodiments (except for the modification A), these buttons are not limiting. Only the first leg portions 42a of the buttons <NUM>, 40B, and 40C may have the depressions <NUM>, or the buttons <NUM>, 40B, and 40C may consist of leg portions having no depression <NUM>. Similarly, the leg portions <NUM> according to the modification A may have inwardly recessed depressions <NUM> in tip direction-side positions thereof adjacent to the side walls 15b of the opening <NUM>.

The shape of the fitting portions 4b of the leg portions <NUM> of the buttons <NUM> and 40A to 40C according to the embodiments is not limited to the examples in the drawings. The opposed surfaces 4r of the fitting portions 4b need not be along the inner wall 12r of the body <NUM>, or the fitting portions 4b may be formed without the protruding portions <NUM>. The buttons <NUM>, 40B, and 40C according to the first to third embodiments may be formed without the come-out prevention portions <NUM>. The shape of the face wall 41a of the buttons <NUM> and 40A to 40C is not limited to the examples in the drawings and can be changed arbitrarily. The surface of the face wall 41a may be subjected to various types of processing for increasing friction. In the conversion units <NUM> and 30A according to the embodiments, the engaging portions <NUM> only have to include one of the first engaging portion 34a and second engaging portion 34b. However, the engaging portions <NUM> preferably include the first engaging portion 34a and second engaging portion 34b in terms of the placement stability of the button <NUM>, the stability thereof during push-own, or the like. While the slider <NUM> according to the first embodiment may be formed without the safety protrusion <NUM>, it preferably includes the safety protrusion <NUM> in terms of the prevention of misoperation, or the like. While the examples in which the chemical solution C is injected into a human or animal have been described above, the injection devices may be used for applications other than such an application. For example, the injection devices may be used to inject a liquid into a food material such as pieces of meat, cells, or the like.

Claim 1:
An injection device (<NUM>, 100A, <NUM>, <NUM>) for being manually operated by a user, the injection device comprising:
a syringe (<NUM>,<NUM>) including a tubular body (<NUM>), the body (<NUM>) having, in a peripheral wall (<NUM>), an opening (<NUM>) having a rectangular shape in a plan view;
a conversion portion (<NUM>,30A) connected to a rear end portion of a gasket (<NUM>) disposed on a tip side of the body (<NUM>), the conversion portion (<NUM>,30A) being contained in the body (<NUM>);
a button (<NUM>,40A,40B,40C) disposed on a side near the opening (<NUM>) of the conversion portion (<NUM>,30A) and supported by the conversion portion (<NUM>,30A) with side portions of the button (<NUM>,40A,40B,40C) sandwiched between both side walls (15b) of the opening (<NUM>); the injection device being characterized by
a slider (<NUM>,<NUM>) disposed in the opening (<NUM>) in the peripheral wall (<NUM>) of the body (<NUM>) and configured to move the conversion portion (<NUM>,30A) and the button (<NUM>,40A,40B,40C) in a tip direction that is a direction in which the gasket (<NUM>) moves toward a tip of the body (<NUM>),
wherein the button (<NUM>,40A,40B,40C) has a cross-sectional U-shape on a plane perpendicular to the tip direction and includes a pair of leg portions (<NUM>) disposed so as to straddle the conversion portion (<NUM>,30A) and having front slopes (<NUM>) inclined with respect to the tip direction by a set angle (θ), and
wherein the conversion portion (<NUM>,30A) includes a pair of engaging portions (<NUM>) formed so as to correspond to the pair of leg portions (<NUM>) and having rear slopes (<NUM>) that slidingly contact the front slopes (<NUM>) and is configured to move in the tip direction in accordance with an operation of pushing down the button (<NUM>,40A,40B,40C) toward inside of the body (<NUM>).