Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
2003-01-09
2004-07-27
Mendez, Manuel (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S131000
Reexamination Certificate
active
06767336
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to improvements in automatic injectors. Additional embodiments include a sharps protector that is manually or automatically operable.
2. Description of the Prior Art
Military personnel under chemical attack are trained to use automatic injectors when an injection is needed on an emergency basis in the field where medical personnel are not available to perform the injection. Civilians or military personnel who are allergic to bee or wasp stings, and the like, may use them when there is no access to emergency medical service (EMS) personnel or insufficient time to travel to a medical facility. Passenger aircraft are often equipped with automatic injectors as well for use when a passenger has a food allergy that creates a medical emergency. Most emergency medical vehicles also carry automatic injectors for the emergency treatment of allergic reactions. There are other uses for automatic injectors as well.
The automatic injector disclosed in expired U.S. Pat. No. 4,031,893, commercially known as the EpiPen® epinephrine auto-injector, invented primarily by the present inventor, has been in widespread use for more than twenty years. The military version thereof is known as the Pralidoxime ComboPen. The user grasps an outer cylindrical sleeve of the injector and delivers the leading end of the device to the injection site with a force sufficient to cause release of a spring-loaded needle. More specifically, when the device is ready to be used, the outer cylindrical sleeve trails an inner cylinder from which the needle or cannula extends so that when the leading end of the outer cylindrical sleeve hits the user's skin, the movement of the trailing end of the outer cylindrical sleeve releases a spring and the spring drives a piston that pushes liquid medicament out of a cartridge and Into the user's tissue through the cannula.
The '893 device fulfilled the needs of its (pre-AIDS) time, but it includes no means for covering the sharp cannula after it has been deployed. Thus, the exposed cannula represents a hazard to those who come into contact with it after it has been withdrawn from the tissue of the user. Nor is it a simple matter to retrofit the cannula with a sharps protector because there is insufficient space within which to mount a sharps protector.
The '893 device also uses a relatively large amount of plastic material in its construction due to the aforesaid outer cylindrical sleeve.
Another drawback of the '893 device is that the user must aim at and hit the desired point of injection in one motion. Impact of the device against the user's body triggers extension of the cannula by causing the release of a loaded piston biasing means if the device works in accordance with its design.
Premature deployment is therefore a problem. For example, the cannula may deploy when the device is placed on any site with slight pressure or when brushed against a surface such as a wrinkle in a pair of trousers. Deformed or misaligned parts may cause such unwanted premature deployment. Such premature activation, caused by the inadvertent application of a slight amount of pressure, is clearly unwanted.
Accordingly, there is a need for an improved automatic injector having a design that reduces the chances of a premature cannula deployment.
There are also a number of factors that can result in a failure of the cannula to deploy properly. For example, the cannula may fail to properly deploy if the auto-injector spring is weak, if the cannula is occluded, if a glass medicament-containing ampule breaks, if the piston sticks to the interior surface of the glass walls of the cartridge holder sleeve, if the device otherwise jams due to a parts misalignment, or the like.
A need therefore exists for an automatic injector having a design that reduces the chances of an improper cannula deployment.
Astronaut suits and other special clothing items include a special (self-sealing) area of the clothing designed to accept a cannula so that an emergency injection may be performed in the absence of a need to remove the clothing. The special area is small and not easy to hit when performing an emergency injection.
Thus there is a need for an automatic injector that would enable the user to position the leading end of the device in juxtaposition with an intended injection site before the needle is triggered.
Moreover, an automatic injector having means for shielding the deployed cannula is needed.
A good design also minimizes the use of natural resources, especially in devices that are used only once and discarded or re-cycled.
A need therefore exists for an automatic injector formed of less material than the automatic injectors of the prior art.
The medicament in an automatic injector may become cloudy due to age or some other cause. it may even leak out of the automatic injector if the ampule that contains such medicament has been damaged. When cloudy or discolored in any way, or if not present in its full effective quantity, the efficacy of the medicament is in doubt. Accordingly, pre-injection visual inspection of the medicament is required to ascertain whether or not it is present and suitable for use. Some of the known automatic injectors such as the EpiPen® have somewhat clear, semi-transparent parts that enable visual inspection of the medicament, but there are three layers of said parts (an outer cylindrical sleeve, a cartridge holder sleeve, and the medicament-containing ampoule). The outer cylindrical sleeve and the cartridge holder sleeve are formed of natural plastic and thus are semi-transparent. The ampoule is formed of clear glass. Thus, if either of the outer two parts become cloudy or otherwise lose at least some degree of transparency, visual inspection of the medicament is hindered.
Thus, there is a need for an automatic injector made of fewer parts so that pre-injection visual inspection of medicament does not require looking through three layers of parts.
An automatic injector can also fail because the medicament contained therewithin may fail to reach the tissue of the patient in whole or in part due to various mechanical malfunctions of the device. For example, it is possible for the cannula to deploy but for none of the medicament, or just a fraction thereof, to actually flow through the cannula into the patient's tissue.
Accordingly, there is a need for an automatic injector made of fewer parts so that post-injection visual inspection of medicament does not require looking through three layers of parts.
From a mechanical standpoint, the more parts a device has, the greater are the chances for a malfunction.
Thus there is also a need for an automatic injector having fewer parts to increase its reliability of operation.
However, in view of the prior art considered as a whole at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the identified needs could be fulfilled.
SUMMARY OF INVENTION
The long-standing but heretofore unfulfilled need for an automatic injector that is constructed of less materials, that has fewer parts, that may be positioned at a preselected location prior to release of the cannula, that provides sharps protection, and that otherwise advances the art is now met by a new, useful, and nonobvious invention.
A cartridge holder sleeve has a lumen that slideably receives a cartridge, a piston, a spring holder, and an inner gun sleeve. The cartridge is adapted to hold a liquid medicament. A cannula hub is mounted to a leading end of the cartridge, and a cannula is mounted to a leading end of the cannula hub. The piston is disposed in trailing relation to the cartridge and the spring holder is disposed in trailing relation to the piston.
A first diameter-reducing shoulder is formed in the cartridge holder sleeve near a leading end thereof. Accordingly, a reduced diameter section of said cartridge holder sleeve is formed in leading relation to said first diameter-reducing shoulder.
A spring-retaining shoulder
Mendez Manuel
Smith Ronald E.
Smith & Hopen , P.A.
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