IL25960A

IL25960A - Hypodermic injector with safety held release means

Info

Publication number: IL25960A
Application number: IL25960A
Authority: IL
Original assignee: Sarnoff S
Priority date: 1965-09-17
Filing date: 1966-06-13
Publication date: 1970-04-20
Also published as: NL6610034A; US3368559A

Description

'JIIUJI fiiD TJini"T ·π- PATENT ATTORNEYS · D'DIDD 'Dill) PATENTS AND DESIGNS ORDINANCE SPECIFICATION Hypodermic injector with safety held release means , o^iisa mfr *y¾B» 07 »arm»*»i pnro STANLEY J. SABNOFF, a citizen of the U.S.A., 7507 Hampden lan , Bethesda, Maryland, fJ.S.A. do hereby declare the nature of this invention and in what manner the same is to be performed, to particularly described and ascertained in and by t following statement :- ThiB Invention relates to improvements in the release mechanisms of hypodermic syringes.

One type of hypodermic syringe comprises a hypodermic injector which can be carried on the person of the user with the needle thereof in a sheathed condition, the device being quickly and easily releasable by removing a safety pin and pressing a tube holding a medicament vial against the portion of the body which is to receive the medicament, while grasping an outer sleeve, the relative movement of sleeve and tube causing the needle to automatically move rapidly outwardly from the tube under the influence of a spring and the medicament in the vial to be ejected through the needle. This spring is normally retained under compression by a detent within the device.

It is possible, in the prior art devices, to inadvertently cause ejection of the needle and ejection of medication after the safety pin has been removed, without relative sleeve and tube movement, this occurring, for example, by reason of rough handling or dropping of the syringe.

It is an object of this invention to provide improved detent means to minimize the chances of inadvertent release of the spring with consequent inadvertent ejection of the needle and medicament.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings, wherein several embodiments of the invention are shown for purposes of illustration, and wherein: Pig, 1 is a cross-sectional view of an improved hypodermic injector, the spring thereof being shown in released position and the Injector incorporating the detent means of this invention; Fig. 2 is a plan view of one form of detent forming part of the invention; Fig. 3 is a plan view of a second form of detent forming part of the invention; and, Fig. 4 is a diagrammatic view illustrating the position of parts with the detent, such as the flat detent of Fig. 2, partially operated for release of the spring.

Reference is made to the disclosure in Sarnoff et al U. S. Patent No. 2,832, 339 for such structure and mode of operation of the syringe as is not wholly disclosed herein.

As a specific embodiment of the invention, Fig. 1 discloses in cross section and in released condition of the spring, an outer sleeve or sheath 10 of plastic or metal open at the lefthand end and closed, except for a perforation 12, at the righthand end 14. Telescoplngly mounted In the outer sleeve is a tube 16, also of plastic or metal, secured in any convenient manner to a metallic spring housing 18, open at the lefthand end 20 and closed by a collar 21 at the righthand end, except for a perforation 22, for the passage therethrough of a detent portion of the shaft to be described. The tube 16 is closed at the lef hand end, except for a perforation 24, to permit extrusion of the needle 26.

Within the lefthand end of the tube 16 is a vial 28, shown in Fig. 1 as emptied of its contents, the vial being provided with a rubber stopper 30, penetrated by the hollow needle, the needle having been driven through the ejected through a passageway In the needle by reason of a piston 32 within the vial having been driven to the left. The drive of piston 32 was effected by displacement of disc member 3 , the disc being driven by the spring seat end 36 of a shaft 38, shaft 38 being driven in turn by reason of release of compression of a helical spring 4o.

The spring reacted between the spring seat on the shaft; and the inside face of collar 21. The shaft, as shown in Pig. 2, is provided near its end opposite the spring seat ^ with a detent portion indicated generally as 42 in Pig. 2. The shaft 38 is cylindrical; the seat 36 is a circular flange and the detent end of the shaft is provided with a conical portion 44 and a slotted portion 46 extending completely through the shaft, the slot in the shaft extending but a short distance above the cone and a much longer distance below the cone . The cone has a surface 38 diverging away from the axis of the shaft in the direction of the seat and a surface 50 extending outwardly from the shaft. This surface is normally parallel to and engages the upper surface of the collar 21 when the spring is under compression and the device cocked for operation. Also in cocked position an integral hollow bridging neck portion 52 of the shaft may extend through aperture 12 in the outer sleeve to receive a locking pin (not shown) inserted into the device to prevent inadvertent unseating of the detent and release of the needle and medicament.

By reason of the slotted construction of the shaft and integral neck 52, however, undeslred sliding of the detent surface 50 from off the collar 21 is made difficult as will become apparent. With the construction of the prior art, pivoting of the arms supporting the detent portion occurs at the closed end of the slot . As a consequence any forces, as inertia forces, incurred when dropping the hypodermic device when the safety pin has been removed, which tends to slightly move the arras toward each other, angle the detent surface which engages the collar to present an acute angle between it and the collar surface, promoting sliding action of the detent surface in a direction to cause release of the shaft.

By reason of the closed-at-both-ends slotted construction disclosed herein, when an unintended force tends to move the detent surface, because of the two pivots provided by the ends of the slot in the shaft and the shortness of the portion of the slot above the surface 50 compared to the remaining portion of the slot, the surface 50 angles in an opposite direction to that which occurs in the prior art. Therefore, as seen diagrama tic ally in Pig.- ", the springnessPin the material of the shaft and the angularity of the surface is such as to tend to restore the detent to locked position.

Normal release of parts is effected by telescoping action of the outer sleeve with respect to the holder for the vial, whereupon the wall surrounding the perforation 12 engages the conical surface portions of the detent and forces them together sufficiently to allow the detent to pass through the opening 22, the slotted portion permitting sufficient flexing of the walls of the shaft to take place to permit this action.

In the modified form of invention shown in Pig. 3, instead of the shaft and seat being cylindrical, the same may be made of a flat bar, as bar 54, rectangular in cross section, thereby saving material. The neck or bridge piece 56 is hollow and cylindrical to permit insertion of the locking pin referred to hereinabove. When no safety pin is employed, the entire shaft, including the bridge piece at the end of the slotted portion, may be flat.

Claims

HAVX&G ROW particularly described and ascertained, the* nature of my eaid invention and in what manner the same is performed* Z declare that what I claim le

1. , A spring propelled control element for a hypodermic injector comprising a shaft of resilient material, a spring seat at one end of the shaft, a slotted portion in the shaft extending from adjacent one end of the shaft but removed from the said one end thereof and extending toward the spring seat, a detent on the shaft adjacent to the said one end of the shaft and positioned Intermediate the length of the slotted portion, the detent comprising a surface sloping divergently in the direction of the spring seat end of the shaft and a second surface intersecting the said first surface and extending laterally from the shaft, the part of the slotted portion between the said second surface and the seat end of the shaft being longer than the remaining part of the slotted portion,

2. , A spring propelled control element according to claim 1, wherein the shaft is a flat member and there is provided a second detent, the detents being at the same level along the length of the shaft and extending from the shaft on opposite sides of the flat member.

3. , A spring propelled control element according to claim 1, wherein the shaft is a cylindrical member, and the portion of the shaft on the said one end thereof is constituted of a collar integral with the portions of the shaft on each side of the slotted portion thereof,

4. , A spring propelled control element according r to any preceding claim, wherein the detent is in the form of a frustum of a cone with the slotted portion passing through the frustum of the cone.

5. A spring propelled control element according to any preceding claim, wherein the resilient material is a plastic,

6. A spring propelled control element according to any of claims 1 to 5, wherein the resilient material is metallic,

7. A spring propelled control element for a hypodermic injector substantially as illustrated by the accompanying drawings, and as described with reference thereto. Dated this 12th day of June, 1966