Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-02-25
2001-04-10
Weiss, John G. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S134000, C604S132000
Reexamination Certificate
active
06213981
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a self-administration device for liquid medicines (hereinafter referred to as the “self-administration device”) and, more particularly to such type of device that is adapted to enable a patient to inject a liquid medicine into his body by himself so to ease pain such as postoperative pain or pain caused by cancer or the like with, or without, the use of a system for continuously injecting a very small amount of a liquid medicine such as an analgesic or a narcotic.
2. Description of Related Art
Recently, in the field of anesthetics, there has been employed an epidural catheterization method using a device capable of continuously injecting a very small amount of a liquid medicine such as an analgesic to control pain such as postoperative pain, pain caused by cancer and the like. However, symptoms of patients vary and there is sometimes a case in which a patient complains of a sudden pain even in the course of continuous injection of an analgesic. In order to cope with such a critical moment, the development of a device which allows a patient to administer an analgesic to himself by a one-shot operation has been in progress. As one example of such a device, there is a liquid medicine self-administration device as described in Japanese Unexamined Patent Published Number H8-308925.
The above-described liquid medicine self-administration device comprises a cylindrical casing having an open end and a closed end provided with a liquid medicine injection port and a liquid medicine delivery port at the closed end thereof, a reservoir housed within the casing so as to cover the liquid medicine injection and delivery ports, and a pushing means mounted on the open end of the casing. This self-administration device is so constructed that when the pushing means is pressed by a patient, the reservoir is pressed by the pushing means and deformed and as a result, the liquid medicine contained in the reservoir flows through the liquid medicine delivery port.
However, the above-described prior art device has the following disadvantages when the device is used by connecting thereto a small tube such as an epidural catheter. That is, since the tube path resistance is high, force is required to deliver the liquid medicine. Further, since it takes a considerable period of time for the liquid medicine to be completely delivered, it is difficult for an enfeebled patient to continue to press the pushing means. In addition, when the pushing means is pressed with an unnecessarily strong force, there is sometimes a case in which the liquid medicine is rapidly delivered from the tip of the catheter so that the tip of the catheter moves out of position or an extremely high internal pressure is applied to the device causing the liquid medicine to leak.
SUMMARY OF THE INVENTION
The present invention has been made in view of the abovedescribed circumstances and an object of the invention is to provide a self-administration device for liquid medicines, which device is capable of administering a liquid medicine to a patient with the application of a predetermined pressure thereon, which is free from the danger of leakage of the liquid medicine and which allows the patient to perform the injection and refilling of the liquid medicine by a one-touch operation.
The above and other objects of the present invention can be achieved by providing a self-administration device comprising: a casing having both ends thereof opened; a port portion provided with liquid medicine inlet and outlet ports and closing one of the open ends of said casing; a reservoir having an open end to be closed by said port portion and a closed end, and which can be easily deformed by pressing and can be easily restored to its original shape; and pushing means for pressing and deforming said reservoir, which is slidably inserted into the other open end of said casing, and is constituted such that when said reservoir is pressed and deformed by said pushing means, a liquid medicine is delivered from said liquid medicine outlet port. The pushing means comprises a cylindrical member inserted slidably into the casing along the inner wall of the casing and a spring member housed within the cylindrical member. An engaging means is provided in the casing such that when the cylindrical member is slid toward the port portion, the engaging means automatically engages the cylindrical member at a sliding end position and can be manually released from the engaging position. By this structure, when the cylindrical member is slid toward said port portion to be brought into engagement with the port portion, the spring member is compressed and the reservoir is pressed by the spring force of the spring member.
Within the above structure, the engaging means comprises an engaging slit formed at the lower end of a skirt portion of said cylindrical member and an engaging hook formed within said casing. Further, the engaging hook comprises a split ring housed within the casing, a push-button provided on the outer peripheral surface of the split ring and projecting outwardly through a window formed in the casing, and an engaging claw being provided vertically on an upper side surface of the split ring and having an inclined surface which causes the split ring to bend inwardly when the surface is pressed by the lower end of said cylindrical member.
Further, the liquid medicine inlet and outlet ports comprises a liquid medicine inlet port connected to a liquid medicine injection tube and a liquid medicine outlet port connected to a liquid medicine delivery tube, the liquid medicine outlet port being provided with a check valve capable of blocking the inflow of the liquid medicine.
Still further, the liquid medicine inlet port and outlet port are connected to a single liquid medicine injection and delivery tube whose tip is connected to a liquid medicine injection tube and a liquid medicine delivery tube through a connector, wherein said liquid medicine delivery tube is provided with a check valve.
As described above, the present invention has the following various advantages, namely:
(1) According to a first feature of the invention, since the spring member is used as a means for pushing the reservoir, there is no fear that the reservoir is pressed by an unnecessarily strong pressing force. Since a constant force presses the reservoir, there is no fear of leakage of the liquid medicine. Further, since the pushing means is automatically held by the engaging means of the pushing means at its sliding end-position, it is sufficient for the patient to merely press the pushing means at the beginning of the injection. Further it is not necessary for the patient to continue to press the pushing means until the liquid medicine is delivered completely, so that the physical burden of the patient can be mitigated. In addition, the refilling of the liquid medicine into the reservoir can be automatically effected with a single action because when the engaging means of the pushing means is manually released, the cylindrical member moves upward by the action of the spring member and the liquid medicine is sucked into the reservoir due to the shape restoration property of the reservoir itself.
(2) According to a second feature of the invention, when the cylindrical member is pushed down, the lower end of the skirt portion of the cylindrical member presses the inclined surface of the engaging claw of the engaging hook and thereby the split ring is bent so that the engaging claw moves inside the cylindrical member and then when the engaging slit of the cylindrical member moves into a position adjacent the engaging claw, the engaging claw moves radially and outwardly to be caught by the engaging slit. Consequently, the engaging claw is automatically held in engagement with the engaging slit of the cylindrical member at the position to which the cylindrical member is slid down. Further, when the push-button is manually pressed, the split ring flexes radially and inwardly to release the engagement of the eng
Hiejima Katsuhiro
Mori Takeshi
Hayes Michael J.
Kubovcik & Kubovcik
Nissho Corporation
Weiss John G.
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