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WO2015149155A1 - Needleless injector - Google Patents

Needleless injector

Info

Publication number
WO2015149155A1
WO2015149155A1 PCT/CA2015/000215 CA2015000215W WO2015149155A1 WO 2015149155 A1 WO2015149155 A1 WO 2015149155A1 CA 2015000215 W CA2015000215 W CA 2015000215W WO 2015149155 A1 WO2015149155 A1 WO 2015149155A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
rear
end
front
barrel
syringe
Prior art date
Application number
PCT/CA2015/000215
Other languages
French (fr)
Inventor
Karim Menassa
Adam GADOUA
Original Assignee
Idee International R&D Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M5/00Devices for bringing media into the body in a subcutaneous, intra-vascular or intramuscular way; Accessories therefor, e.g. filling or cleaning devices, arm-rests
    • A61M5/178Syringes
    • A61M5/30Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules

Abstract

A needleless injector includes a tubular barrel including a front section for receiving a disposable syringe; middle and rear sections containing a hammer and a compression spring for driving the hammer forwardly against the syringe plunger, a compression screw in the front section and threaded into the middle section for compressing the spring, a rear lock assembly for locking the hammer in a cocked position, and an actuating button for releasing the hammer, whereby the hammer drives against the syringe plunger to eject liquid from the syringe.

Description

NEEDLELESS INJECTOR

This invention relates to a needleless injector, and in particular to a tubular needleless injector for making small dosage injections.

While there are many patents and other publications describing tubular needleless injectors, problems with such devices include the ability to accurately administer small doses of medicine or other liquids subcutaneously and complicated mechanisms for operating the injectors.

The present invention provides a solution to the above-mentioned problems in the form of a relatively simple needleless injector which enables accurate subcutaneous injection of liquids.

According to one aspect, the invention relates to a needleless injector comprising: a tubular outer barrel including a front section, a sleeve slidable on a front end of the front section, a middle section, a rear section and a rear cap; a hollow, externally threaded compression screw in the outer barrel extending from a front end of the sleeve into a front end of the middle section, whereby rotation of the sleeve causes sliding of a rear end of the sleeve relative to the middle section; a syringe barrel extending through the front section and into the compression screw for receiving a syringe; a hammer slidable in said middle and rear sections of the outer barrel for driving a plunger in the syringe forwardly to discharge liquid from the syringe, rearward movement of the sleeve and compression screw causing a corresponding rearward movement of the hammer in the outer barrel; a helical drive spring coaxial with a rear end of the hammer for compression by the hammer during rearward movement of the hammer; a housing in said outer barrel connected to a rear end of the rear section and to a front end of said rear cap, a rear end of the hammer being slidable in the housing; a rear lock assembly in the housing for releasably locking the hammer in a rear, cocked position in which a front end of the hammer is spaced apart from a rear end of the syringe plunger; and an actuating button slidable in the rear cap for releasing the hammer from the rear lock assembly, whereby the drive spring expands to drive the hammer forwardly against the rear end of the syringe plunger to expel liquid from the syringe under pressure.

In accordance with a second aspect, the invention relates to a needleless injector comprising: a tubular outer barrel including a front section for receiving a syringe, a middle section, a rear section and a rear cap; a hollow, externally threaded combination compression screw and syringe barrel in the outer barrel extending from a front end of the front section into a front end of the middle section; a nut on a rear end of the compression screw, rotation of the front section causing movement of the nut relative to the compression screw;

a hammer slidable in said middle and rear sections of the outer barrel for driving a plunger in the syringe forwardly to discharge liquid from the syringe, rearward movement of the nut causing a corresponding rearward movement of the hammer in the outer barrel; a helical drive spring coaxial with a rear end of the hammer for compression by the hammer during rearward movement of the hammer; a rear lock assembly in the rear section of the outer barrel for receiving a rear end of the hammer and releasably locking the hammer in a rear, cocked position in which a front end of the hammer is spaced apart from a rear end of the syringe plunger; and an actuating button slidable in the rear cap for releasing the hammer from the rear lock assembly, whereby the drive spring expands to drive the hammer forwardly against the rear end of the syringe plunger to expel liquid from the syringe under pressure.

The invention is described below in greater detail with reference to the accompanying drawings, which illustrate a preferred embodiment of the injector, and wherein:

Figure 1 is an isometric view of the needleless injector;

Figure 2 is a front view of the injector of Fig. 1 ;

Figure 3 is a partly sectioned, isometric view of the injector of Fig. 1 ;

Figure 3B is an isometric view of detail B in Fig. 3;

Figure 4 is an exploded, isometric view of the injector of Figs. 1 to 3;

Figure 5, is a cross section taken generally along line 5-5 of Fig. 2;

Figures 6 and 7 are longitudinal sectional views of the front end of the injector of Figs. 1 to 5;

Figure 8 and 9 are longitudinal sectional views of portions of the rear end of the injector of Figs. 1 to 5;

Figure 10 is an exploded, isometric view of selected elements of the rear end of the injector;

Figure 11 is an isometric view of a second embodiment of the needleless injector;

Figure 12 is a front view of the injector of Fig. 11 ; Figure 13 is a longitudinal sectional view of the injector of Figs. 11 and 12;

Figure 14 is an exploded, isometric view of the injector of Figs. 11 to 13;

Figure 15 is a side view of the barrel of a disposable syringe used in the injector of Figs. 11 to 14;

Figure 16 is a side view of a compression screw used in the injector of Figs. 11 to 14;

Figure 17 is a partly sectioned, exploded side view of the syringe;

Figure 18 is an isometric view of the plunger of the syringe of Fig. 17;

Figure 19 is a cross section taken generally along line 19-19 of Fig. 16;

Figure 20 is a cross section taken generally along line 20-20 of Fig. 16;

Figure 21 is an isometric view of a middle section of the barrel of the injector of Figs. 11 to 14;

Figure 22 is a longitudinal sectional view of a sleeve used in the injector of Figs. 11 to 14;

Figure 23 is a longitudinal sectional view of the body of a ball lock assembly used in the injector of Figs. 11 to 14;

Figure 24 is a cross section taken generally along line 24-24 of Fig. 23;

Figure 25 is a longitudinal sectional view of a ball slider used in the ball lock assembly;

Figure 26 is an exploded isometric view of an actuating button and a safety interlock mechanism used in the injector of Figs. 11 to 14;

Figure 27 is an isometric view of the button and interlock assembly of Fig. 26 in the assembled condition; Figure 28 is a rear view of a spring washer used in the interlock assembly of Figs. 26 and 27;

Figure 29 is a cross section taken generally along line 29-29 of Fig. 28;

Figure 30 is a side view of a locking ring used in the interlock assembly of Figs. 25 and 26;

Figure 31 is a front end view of the locking ring of Fig. 30;

Figure 32 is an isometric view of the actuating button of Figs. 25 and 26, and

Figure 33 is a longitudinal sectional view of the actuating button of Fig. 32.

With reference to Figs. 1 to 4, the needleless injector includes an elongated, tubular outer barrel indicated generally at 1. The outer barrel is defined by a sleeve 2 slidable on the front end 3 of a front section 4, which receives a disposable syringe 5, a middle section 6, a rear section 7 and a rear cap 8 which receives an actuating button 9 rotatable in the cap 8. A pair of diametrically opposed wings 10 and 11 extend radially outwardly from the front and rear sections 4 and 7, respectively, for facilitating rotation of the front section 4 and its contents relative to the middle and rear sections 6 and 7, respectively.

The disposable syringe 5 is releasably mounted in the front end of a syringe barrel defined by syringe barrel defined by a ball clutch mechanism indicated generally at 12 (Figs. 4-6). The ball clutch mechanism is a lock assembly for releasably locking the syringe 5 in the injector. The syringe 5 includes a tubular barrel 14 with a large head 15 for limiting movement of the syringe into the injector. Longitudinally extending ridges 16 on the head 15 facilitate manual manipulation of the syringe. As best shown in Fig. 6, a plunger 17 with a large rear end 18 is slidable in the barrel 14 for pushing liquid through an injection orifice 20 in the head 15 of the syringe. An O-ring 21 on the plunger 17 forms a seal between the barrel and the plunger.

The ball clutch mechanism 12, which defines a front lock assembly for releasably locking the syringe in the injector, and includes a tubular body 22 with an externally threaded rear end 23 for mating with the internally threaded front end 25 of a compression screw 26. External threads 27 on the front end 25 of the screw 26 engage threads 29 in the front end of the front barrel section 4. The sleeve 2 is biased forwardly by a helical spring 31 on the body 22. The spring 31 extends between the front end of the screw 26 and a shoulder 33 in the sleeve 1. A plurality of balls 34 are disposed in countersunk holes 36 in the body 22.

When the syringe 5 is inserted into the front end of the barrel section 4, the balls 34 enter an annular groove 37 (Figs. 4, 5 and 7) in the barrel 14 of the syringe locking the syringe in the injector. At the same time, a helical spring 38 sandwiched between the rear end 40 of a tubular syringe ejector 41 in the screw 26 and an annular shoulder 42 in the screw is compressed (Figs. 6 and 7). The ejector 41 receives the rear end of the syringe 5, and the front end 43 of the ejector 41 bears against a shoulder 44 (Figs. 4 and 7) on the syringe barrel 14. In order to remove the syringe 5, the sleeve 2 is pushed rearwardly, compressing the spring 38. Rearward movement of the sleeve 2 permits the balls 34 to move radially outwardly into grooves 45 (Fig. 6) in the sleeve 2, whereby the syringe is released. The spring 38 pushes the ejector 41 forwardly, causing the syringe 5 to be forcibly ejected from the barrel 1.

Liquid is discharged from the syringe 5 when the plunger 17 is driven forwardly by a hammer 46. A head 47 at the front end of the hammer is slidable in the ejector 41. Forward movement of the hammer 46 is limited by a stop 48 on the rear end of the screw 26. The stop 48 has an externally threaded, tubular body 50 (Fig. 4) for mating with the internally threaded rear end 51 of the screw 26, and an annular flange 52 for limiting movement of the stop into the screw 26. During forward movement in the barrel 1 , the head 47 at the front end of the hammer strikes the large rear end 18 of the syringe plunger 17. An annular flange 54 on the hammer 46 limits forward movement of the hammer in the barrel. When the hammer 46 moves forwardly to fully discharge the liquid from the syringe, the flange 54 hits the flange 52 on the rear end of the stop 48.

A drive spring 56, which is coaxial with the hammer 46, extends between the rear face of the hammer flange 54 and the annular front end 57 (Figs. 4, 8 and 9) of a tubular, externally threaded housing 58 mounted in the rear end 59 of the rear section 7 of the barrel. The housing 58 contains a rear ball lock assembly indicated generally at 61 (Figs. 8 and 9). As best shown in Figs. 8 to 10, the lock assembly 61 includes a tubular ball cage 62 mounted in the housing 58. External threads on a flange 64 on the cage 62 engage threads 66 (Fig. 10) in the front end 57 of the housing 58. Holes 67 in the cage 62 receive balls 68 when the hammer 46 is in the forward injection position (Fig. 9). Referring again to Figs. 1 to 3, when the wings 10 on the front barrel section 3 are grasped using the thumb and index finger of one hand, and the wings 11 on the rear barrel section 7 are grasped using the thumb and index finger of the other hand, the middle and rear sections 6 and 7, respectively, of the body are rotated relative to the front section 4. During rotation of the middle and rear sections 6 and 7, respectively, the middle section 5 is threaded onto the compression screw 16, moving the middle and rear sections 6 and 7,

respectively, forward relative to the front section 4. Thus, the main drive spring 56 is compressed as the middle section 6 moves into the front section 4, i.e. as the hammer 46, in effect, moves rearwardly into the housing 58 in the rear barrel section 6. During movement of the barrel sections, the rear end 70 of the hammer 46 slides in a front end 71 of the ball cage 62 which extends forwardly from the front end 57 of the housing 58.

As the housing 58 moves forwardly, the balls 68 enter an annular groove 73 proximate the rear end of the hammer 46 to retain the hammer in the cocked position (Fig. 9). At the same time, a helical spring 74 retained in the rear end of the ball cage 62 by an internally threaded cap 76 on the externally threaded rear end of the ball cage. The spring 74 is housed in a top hat-shaped cup 77 inserted in the rear end of the ball cage 62.

In the cocked position, the balls 68 are held in the groove 73 by a collar 78 slidable on the ball cage 62. As best shown in Fig. 10, the collar 78 is stepped, i.e. has a narrow diameter front end 80 and a wider diameter rear end 81 with a shoulder 82 therebetween. When the injector is in the cocked condition (Fig. 8), the narrow diameter front end 80 of the collar 78 retains the balls 68 in the rear hammer groove 73. The collar 78 is biased rearwardly by a helical spring 83, which is sandwiched between the inside of the front end 57 of the housing 58 and the exterior front end of the collar shoulder 82. In the cocked condition of the injector (Fig. 8), the spring 83 is extended. When the injector is being fired, the spring compresses, allowing the collar 78 to slide forwardly on the ball cage 62 to a forward position (Fig. 9) in which the balls 68 enter the larger diameter rear end 81 of the collar 78, releasing the hammer 46.

The injector is actuated using the button 9, which is retained in the barrel 1 by the cap 8. The internally threaded front end 85 of the cap 8 is connected to the externally threaded ball clutch housing 58. The rear end 86 of the cap 8 engages a shoulder 87 on the button 9. As best shown in Figs. 2, 3 and 3B, a torsion/ compression spring 90 is sandwiched between the rear end 91 of the cap 76 and a shoulder 92 in the button 9. The rear end 91 of the cap 76 and the shoulder 92 in the button 9 include opposed annular rows of teeth 94 and 95, respectively, which are engaged by opposite ends of the torsion/compression spring 90 to prevent rotation of the spring relative to the button 9 and the cap 76.

The injector incorporates a safety interlock mechanism which prevents the injector from being actuated accidentally. The interlock mechanism includes a plurality of locking tabs 97 (one shown in Figs. 3, 3B, 8 and 9) on the button 9 for engaging boss 98 in the cap 8. In order to actuate the injector, the button 9 must be turned to a preset angle where the locking tab 97 engages a boss 98 to retain the button 9 in the firing position. The injector can then be actuated by pressing the button 9. Following injection, the spring 90 rotates the button 9 in the opposite direction, and the spring returns the button 9 to the start position.

In operation, as described above, the wings 10 and 11 on the front and rear barrel sections 4 and 7, respectively, are grasped, and the middle and rear sections 6 and 7, respectively, are rotated relative to the front section 4 to compress the drive spring 50 fully and lock the hammer 46 in the cocked position. The middle and rear sections 6 and 7 are then rotated in the opposite direction, i.e. backed off to the maximum. A prefilled disposable syringe is inserted into the front end of the barrel 1 and locked in position using the ball clutch mechanism 12.

The middle and rear barrel sections 6 and 7, respectively, are advanced until a small drop of liquid is ejected from the syringe 5, at which point the front end 47 of the hammer 46 abuts the rear end 18 of the syringe plunger 17. An injection can now be effected at minimum pressure by pressing the button 9. At such a minimum pressure, the injection would, for example, be intradermal. If a higher pressure is required, e.g. for subcutaneous injection, the middle and rear barrel sections 6 and 7 are retracted to create a gap between the front end 47 of the hammer 46 and the rear end 18 of the plunger 17.

Reference is made to Figs. 11 to 33 which show the second embodiment of the injector. The injector of Figs. 11 to 33 is specifically designed for administering small subcutaneous doses, e.g. 0.1 ml of a medicine or other liquid. As best shown in Figs. 11 and 13, the injector includes an elongated tubular barrel indicated generally at 110. The barrel 110 is defined by a front section 111, which receives a disposable syringe 112, a middle section 113, a rear section 115, and a rear cap 116 for receiving an actuating button 117, which is rotatable in the cap 116. Three radially extending wings 118 and 119 are provided on the front and rear sections 111 and 115, respectively for facilitating manual rotation of the front section 111 relative to the middle and rear sections 113 and 115, respectively. The wings 118 and 119 are spaced equidistant apart.

With reference to Figs. 12 to 16, the disposable syringe 112 includes a tubular barrel 120 with a large head 121. An annular flange 122 at the rear end of the head 121 limits movement of the syringe 112 into the front section 111 of the injector barrel 110. Longitudinally extending ridges 123 on the head 121 facilitate manual manipulation of the syringe 112. Threads 125 behind the flange 122 mate with threads in the front end 126 of a compression screw 127 (Fig. 13, 14 and 16) for mounting the syringe 112 in the injector. External threads 129 on the front end of the screw 127 mate with threads 130 in the front end of the front barrel section 111 to retain the screw in the barrel 110.

A plunger 131 (Figs. 16 and 18) is slidable in the syringe barrel 120 for pushing liquid through an injection orifice 133 (Figs. 12 and 17) in the barrel head 121. As best shown in Figs. 17 to 20, the plunger 131 includes a generally cylindrical body 135 with portions removed along most of the length thereof to reduce the amount of plastic used in the plunger and to reduce friction between the plunger and the barrel 120. Rails 136 extend along most of the length of the body 135. Grooves 137 in the body 135 provide an indication of the dosage of liquid in the syringe, i.e. the five grooves 137 provide a visual indication of 0.1 - 0.5 ml dosages in the syringe. The large rear end 138 of the body 135 absorbs the shock of a hammer 139 (Figs. 13 and 14) striking the plunger 131 and limits movement of the plunger into the syringe barrel 120 during an injection. The end 138 of the body 135 also facilitates gripping of the body for pulling the body out of the syringe barrel 120 during loading. An O-ring 141 (Fig. 18) in a groove 142 (Fig. 17) in the plunger 131 seals the plunger in the syringe barrel 120.

During an injection, the generally conical front end 143 of the plunger 131 sides into a conical front end 145 of the passage 146 through the barrel 120. A line of weakness defined by an annular groove 147 is provided in the front end 143 of the plunger 131. A similarly shaped ridge 148 is provided in the front end 145 of the passage 146. When the plunger 131 is fully in the barrel 120, the ridge 148 is located in the groove 147, locking such front end 143 in the barrel 120. If the plunger 131 is retracted, the front end 143 breaks away from the remainder of the plunger and remains in the barrel 120, blocking the orifice 133, rendering the syringe unusable.

Movement of the compression screw 127 into the front barrel section 111 is limited by an annular flange 150 (Figs. 3 and 16) near the front end of the screw. An internally threaded nut 151 is mounted on the externally threaded rear end 152 (Figs. 14 and 16) of the screw 127. A lug 154 on the nut 151 extends into a notch 155 in a projection 156 at the front end of the middle section 113 of the barrel 110. The rear end of the middle section 113 is a snap fitted into the front end 157 of the rear barrel section 115. As best shown in Fig. 21 , the rear end of the middle barrel section 113 includes notches 158 permitting flexing of such rear end during insertion into the rear barrel section 115.

When cocking the injector, the front section 111 is rotated relative to the middle and rear sections 113 and 115, respectively causing the nut 151 to move rearwardly on the screw 127. As the nut 151 moves rearwardly, the lug 154 slides in the notch 155 in the front end of the middle section 113 of the barrel 111. An indicator line 159 around the barrel section 113 provides an indication that the front barrel section 111 is at the correct location on the middle barrel section 113 in the cocked or ready to fire position.

The nut 151 is mounted in the front end 161 of sleeve 162 (Figs. 4 and 22) which has external threads 163 near its rear end 164 for engaging threads 165 (Fig. 13) in the rear barrel section 115 (Fig. 13). As shown in Fig. 13, the sides 166 of the front end of the sleeve 162 are crimped. An inwardly extending, annular flange 167 on the front end 161 of the sleeve 162 abuts the front end of the nut 151. The lug 154 on the nut 151 extends through a slot 168 in the sleeve 162 which causes the nut and the sleeve to remain fixed when the front barrel section 111 is rotated relative to the middle and rear sections 113 and 115, respectively.

Liquid is discharged from the syringe 120 when the plunger 131 is driven forwardly by the hammer 139. A head 170 at the front end of the hammer 139 is slidable in an externally threaded, tubular limiter 172 mounted in the internally threaded rear end of the screw 127. The limiter 172 limits forward movement of the hammer 139. During forward movement in the barrel 110, the head 170 of the hammer 139 strikes the large rear end 138 of the syringe plunger 131. An annular flange 173 behind the hammer head 170 limits forward movement of the hammer 139 in the barrel 110. When the hammer 139 moves forwardly to fully discharge liquid from the syringe 120, the flange 173 hits a flange 174 (Fig. 14) on the rear end of the limiter 172.

A helical drive spring 175 which is coaxial with the hammer 139, extends between the rear of the flange 173 and the annular flange 176 at the front end of a ball lock cage assembly indicated generally at 177 (Fig. 14) in the rear end of the sleeve 162. The spring 175 is housed in a spring cage 179 mounted in the sleeve 162 and extending between the rear end of the nut 151 and the flange 176 at the front end of the ball lock cage assembly 177. The spring 175 is stabilized in the spring cage 179 by spring guides 180 and 181 (Fig. 14). Each guide 180 and 181 includes a tubular body 183, and a polygonal flange 184. The front spring guide 180 abuts the hammer flange 173, and the rear spring guide 181 abuts the flange 176 at the front end of the body or housing 185 of the ball lock cage assembly 177.

During compression of the spring 175, the front guide 180, slides rearwardly in the front end 186 of the cage 179 until the flange 184 encounters an internal shoulder 187 (Fig. 13) in the cage. For such purpose the internal diameter of the front end 186 of the cage 179 is larger than that of the rear end 188 (Fig. 14) thereof. One side of the flange 184 on the rear guide 181 extends into a groove 190 (Fig. 13) in the rear end 188 of the spring cage 179, and thus is sandwiched between the cage 179 and the ball lock assembly 177.

As best shown in Figs. 14 and 23 to 25, the ball lock assembly includes the tubular body 185 mounted in the rear end of the sleeve 162, the annular flange 176 on the front end of the body 185, and three holes 193 spaced equidistant apart in the body 185. The body 185 of the ball lock assembly 177 is retained in the sleeve 162 by a retaining ring 194 mounted in a groove 195 in the sleeve 162 behind the flange 176. A split retaining ring 196 (Figs. 14 and 23) is mounted in a groove 198 in the rear end of the body 185. The holes 193 in the body 185 are intended to receive balls 199, which releasably lock the shaft 139 in the cocked position. During rearward movement of the shaft 139, the balls 199 drop into an annular groove 200 (Fig. 14) in the rear end of the shaft. The balls 199 are retained in the groove 200 by a tubular ball slider 202 (Figs. 13, 14 and 25). The ball slider 202 has a narrow diameter front end 203, a larger diameter rear end 204 and a radially inwardly extending flange 205 partially closing the rear end. When the hammer 139 is in the forward position (Fig. 11), the balls 199 are in the rear end 204 of the slider 202 abutting an internal shoulder 206 between the front and rear ends 203 and 204, respectively.

A helical compression spring 207 is mounted on the front end 203 of the slider 202 for biasing the slider rearwardly. When the shaft 139 moves rearwardly and the balls 199 enter the groove 200 in the shaft, the slider 202 is pushed rearwardly by the spring 207 to a position in which the narrow front end 203 retains the balls in the groove. With the hammer 139 locked in the retracted or cocked position, the front barrel section 111 is moved relative to the rear barrel section 115 until the rear end of the front section meets the indicator line 159. Simultaneously the space between the head 170 of the hammer 139 is reduced so that the hammer strikes the plunger 131 with only the force necessary to discharge all of the liquid from the syringe 112. It will be appreciated that the space between the hammer head 170 and the rear end 138 of the syringe plunger 131 dictates the strength of the injection which is important when making a subcutaneous injection. When an injection occurs, the balls 199 are pushed outwardly into the rear end 204 of the slider 202 (the position shown in Fig. 13).

As mentioned hereinbefore, in order to effect an injection, it is necessary to push the button 117 forwardly in the cap 116 at the rear end of the barrel 110. As best shown in Figs. 26 and 27, the cap 116 includes an externally threaded narrow front end 208 for connecting the cap to the internally threaded rear end 164 of the sleeve 162.

The injector incorporates a safety interlock mechanism which prevents the injector from being actuated accidentally. The interlock mechanism, which is best illustrated in Figs. 26 and 27, includes a cam ring 210, a helical spring 211 , a spring washer 212 and a locking ring 213. These elements and the button 117 are assembled in the cap 116. The first step in the assembly of the interlock mechanism is to insert the spring 211 and the locking ring 212 into the cam ring 210. The cam ring 210 is defined by a tubular body 215 with three generally L- shaped fingers 216 extending rearwardly from the body 215. A slot 217 extends the length of the body 215 for receiving a forwardly extending front end 219 of the spring 211. During assembly of the mechanism, the spring 211 is placed in the cam ring 210 so that the front end 219 of the spring 211 extends through the slot 217, and the locking ring 212 is snapped into the body 215 of the cam ring 210. The radially inwardly extending rear ends 220 of the arms 216 retain the spring 211 against an inner front flange 222 in the ring 210, and retain the locking ring 212 against the rear end of the spring 211. The locking ring 212 includes notches 224, one of which receives a rearwardly extending second end 225 of the spring 211. In the assembled condition, an ear 227 on the rear of the spring washer 212 extends into aligned notches 229 and 230 and the locking ring 213 and the large diameter front end 231 of the button 116, respectively.

With reference to Figs. 30 and 31 , as well as the notch 229, the front end of the locking ring 213 includes three generally L-shaped notches 233, with radially outwardly inclined fingers 234 partially closing the front end of the notches.

As illustrated in Fig. 26, the locking ring 213 is glued into the front end 231 of the button 117. Stepped notches 236 in the front end 231 of the button and rearwardly of the notches 233 define cam surfaces including a step 237 and a well 238 for the fingers 220 on the cam ring 210. When assembling the button and interlock mechanism. As mentioned above, the spring 211 and the washer 212 are first inserted into the cam ring 210. The combination of elements thus produced is then inserted into the front end of the button 117. Finally, the assembled cam ring 210, spring 211 , spring washer 212, locking ring 213 and button body are inserted into the rear cap 116, and the front end of the cam ring 210 is glued to the front end of the cap 16. Thus, the cam ring 210 is fixed in the cap 116, and the button 117 with the attached locking ring 213 and the spring washer 212 are free to move longitudinally and rotate in the cap 116, and the spring 211 can be compressed in the cam ring 210.

In the rest or post-injection condition (Fig. 13) of the injector the button 117 cannot be pushed or rotated in the cover 116, because the spring 211 biases the locking ring 213 and the button 117 to a position in which the rear ends of the fingers 216 abut the cam steps 237 in the stepped notches 236. When the hammer 139 has been moved rearwardly to the cocked position by rotating the front barrel section 111 relative to the middle and rear sections 113 and 115, the injector is ready for activation. In order to release the safety interlock, the button 117 must be rotated so that the fingers 216 become aligned with the wells 238 in the notches 236. The spring 211 pushes the fingers 216 into the wells, releasing the button 117, which can then be pushed to effect an injection.

Claims

CLAIMS:
1. A needleless injector comprising:
a tubular outer barrel including a front section, a sleeve slidabie on a front end of the front section, a middle section, a rear section and a rear cap;
a hollow, externally threaded compression screw in the outer barrel extending from a front end of the sleeve into a front end of the middle section, whereby rotation of the sleeve causes sliding of a rear end of the sleeve relative to the middle section;
a syringe barrel extending through the front section and into the
compression screw for receiving a syringe;
a hammer slidabie in said middle and rear sections of the outer barrel for driving a plunger in the syringe forwardly to discharge liquid from the syringe, rearward movement of the sleeve and compression screw causing a
corresponding rearward movement of the hammer in the outer barrel;
a helical drive spring coaxial with a rear end of the hammer for compression by the hammer during rearward movement of the hammer;
a housing in said outer barrel connected to a rear end of the rear section and to a front end of said rear cap, a rear end of the hammer being slidabie in the housing;
a rear lock assembly in the housing for releasably locking the hammer in a rear, cocked position in which a front end of the hammer is spaced apart from a rear end of the syringe plunger; and an actuating button slidable in the rear cap for releasing the hammer from the rear lock assembly, whereby the drive spring expands to drive the hammer forwardly against the rear end of the syringe plunger to expel liquid from the syringe under pressure.
2. The needleless injector of claim 1 including a front lock assembly in the syringe barrel for releasably locking the syringe in the front section of the outer barrel and in the compression screw.
3. The needleless injector of claim 2, wherein the front lock assembly is a ball clutch mechanism for locking the syringe in the syringe barrel and forcibly ejecting the syringe from the syringe barrel after liquid has been expelled from the syringe.
4. The needleless injector of claim 3 including a plurality of wings on each of the front and rear sections of the outer barrel for facilitating rotation of the front section and the compression screw relative to the middle and rear sections of the outer barrel.
5. The needleless injector of claim 4, wherein each of the front and rear sections of the outer barrel includes two diametrically opposed, radially extending wings.
6. A needleless injector comprising:
a tubular outer barrel including a front section, for receiving a syringe, a middle section, a rear section and a rear cap;
a hollow, externally threaded combination compression screw and syringe barrel in the outer barrel extending from a front end of the front section into a front end of the middle section;
a nut on a rear end of the compression screw, rotation of the front section causing movement of the nut relative to the compression screw;
a hammer slidable in said middle and rear sections of the outer barrel for driving a plunger in the syringe forwardly to discharge liquid from the syringe, rearward movement of the nut causing a corresponding rearward
movement of the hammer in the outer barrel;
a helical drive spring coaxial with a rear end of the hammer for
compression by the hammer during rearward movement of the hammer;
a rear lock assembly in the rear section of the outer barrel for receiving a rear end of the hammer and releasably locking the hammer in a rear, cocked position in which a front end of the hammer is spaced apart from a rear end of the syringe plunger; and
an actuating button slidable in the rear cap for releasing the hammer from the rear lock assembly, whereby the drive spring expands to drive the hammer forwardly against the rear end of the syringe plunger to expel liquid from the syringe under pressure.
7. The needleless injector of claim 6, including a plurality of wing on each of the front and rear outer barrel sections for facilitating rotation of the front section and the compression screw relative to the middle and rear sections of the barrel.
8. The needleless injector of claim 7, wherein each of the front and rear outer barrel sections includes three radially extending wings spaced equidistant apart.
PCT/CA2015/000215 2014-04-01 2015-04-01 Needleless injector WO2015149155A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US201461995004 true 2014-04-01 2014-04-01
US61/995,004 2014-04-01

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WO2015149155A1 true true WO2015149155A1 (en) 2015-10-08

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Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB717667A (en) * 1949-09-01 1954-11-03 George Norton Hein Improvements relating to hypodermic injection apparatus
US3805783A (en) * 1971-02-12 1974-04-23 A Ismach Hand powered hypodermic jet injector gun
EP0406778A1 (en) * 1989-07-05 1991-01-09 Erdélyi Dr. Dipl.-Ing. Gyula Needleless inoculator
CA2021566A1 (en) * 1990-07-19 1992-01-20 Istvan Lindmayer Needleless injector
US5782802A (en) * 1996-03-22 1998-07-21 Vitajet Corporation Multiple use needle-less hypodermic injection device for individual users
WO2005018720A1 (en) * 2003-08-21 2005-03-03 Lindmayer S Istvan Needleless injection device and cartridges
WO2009000786A2 (en) * 2007-06-25 2008-12-31 Novartis Ag Dispensing means with lockable dose adjuster and one way valve
CN202128744U (en) * 2011-05-10 2012-02-01 广州医学院第二附属医院 Portable hemodialysis system
WO2013019939A2 (en) * 2011-08-02 2013-02-07 Pharmajet, Inc. Needle-free injection device
US20130190685A1 (en) * 2010-05-28 2013-07-25 Min-Su Cho Needleless injector
CN103550848A (en) * 2013-11-18 2014-02-05 江西三鑫医疗科技有限公司 Needle-free syringe

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB717667A (en) * 1949-09-01 1954-11-03 George Norton Hein Improvements relating to hypodermic injection apparatus
US2737946A (en) * 1949-09-01 1956-03-13 Jr George N Hein Hypodermic injection apparatus
US3805783A (en) * 1971-02-12 1974-04-23 A Ismach Hand powered hypodermic jet injector gun
EP0406778A1 (en) * 1989-07-05 1991-01-09 Erdélyi Dr. Dipl.-Ing. Gyula Needleless inoculator
CA2021566A1 (en) * 1990-07-19 1992-01-20 Istvan Lindmayer Needleless injector
US5782802A (en) * 1996-03-22 1998-07-21 Vitajet Corporation Multiple use needle-less hypodermic injection device for individual users
WO2005018720A1 (en) * 2003-08-21 2005-03-03 Lindmayer S Istvan Needleless injection device and cartridges
WO2009000786A2 (en) * 2007-06-25 2008-12-31 Novartis Ag Dispensing means with lockable dose adjuster and one way valve
US20130190685A1 (en) * 2010-05-28 2013-07-25 Min-Su Cho Needleless injector
CN202128744U (en) * 2011-05-10 2012-02-01 广州医学院第二附属医院 Portable hemodialysis system
WO2013019939A2 (en) * 2011-08-02 2013-02-07 Pharmajet, Inc. Needle-free injection device
CN103550848A (en) * 2013-11-18 2014-02-05 江西三鑫医疗科技有限公司 Needle-free syringe

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