Injection device

Details Injection device Injection device

1996-12-02

2001-06-05

Sykes, Angela D. (Department: 3762)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S208000, C604S211000, C604S232000

Reexamination Certificate

active

06241709

ABSTRACT:

The invention relates to an injection device that can preferably administer a number of injections from the contents of a container in the injection device. For example, this kind of injection device is used by patients with pernicious anemia in order to give themselves regular injections of hydroxycobalamin.
In devices of this kind that are used by laymen, it is important that the operation is simple and easy to understand, and that the injection does not cause much pain. It is also desirable that the patient who has a particular fear of needles does not see the needle directly.
BACKGROUND
A great number of semi-automatic and fully automatic injection devices have been disclosed. Their construction is often very complex so that manufacturing costs are high. If after being used, a device is not intended for reuse but for disposal or recycling, then a device of this kind has to be composed of few parts and be very cheap to manufacture. Most injection devices which operate semi-automatically or fully automatically do not meet this demand. See for example the fully automatic injection devices according to DE 39 14 818-A1, DE 40 13 769-A1, or DE-UM 92 00 192 (all by Adamaszek). These devices require a first spring for the insertion of the needle and a second spring for the injection of the fluid, and furthermore, corresponding control devices that trigger the injection process by means of the second spring only when the insertion of the needle is finished, as a result of which these devices become very complex and expensive.
It is a task or objective of the invention to provide a new injection device.
SUMMARY OF THE INVENTION
This object is achieved according to the invention by an injection device comprising a housing and an injection fluid container which is displaceable in relation to this housing, between a distal and a proximal end position. The device also comprises a pushrod movable, in relation to the housing, to expel fluid from the container. A first connecting device, which acts in a position-dependent and/or direction-dependent manner, is provided between the pushrod and the container. The connecting device between the pushrod and the container is thus preferably a controlled connecting device, i.e. the container follows the motion of the pushrod only when it is logical and required for the operation of the device. Preferably, this connecting device is controlled by the position of the container relative to the housing.
In a movement of the pushrod in the distal direction, the first connecting device is advantageously adapted to produce a unidirectional, positive connection between the pushrod and the container and to move the latter along with the pushrod in the distal direction, and it is furthermore so formed to convert a movement of the pushrod in the proximal direction into a corresponding movement of the container in the proximal direction as long as the container is not prevented from moving in the proximal direction in the housing. Therefore, during a distal movement, the pushrod is positively coupled to the container, that is, their movements are “positively synchronized”, but a proximal movement of the pushrod will move the container only until it has reached its proximal end position in the housing, for example, whereafter the proximal movement of the pushrod will occur independently of the container, in order to expel fluid from the container.
Suitably, the unidirectional, positive connection is formed so that an abutment for the distal movement of the container also constitutes a limitation for the distal movement of the pushrod. Thus, if the container reaches its distal end position, then a further movement of the pushrod in the distal direction is prevented.
According to another embodiment of the invention, in the distal end position of the container, the first connecting device acts in both the proximal and the distal direction, but in the proximal end position of the container, it is only effective when the pushrod moves in the distal direction. This produces reliable operation having a simple structure.
Another very preferable embodiment of the invention relates to an injection device which has a drive mechanism for the pushrod and a second connecting device provided between the drive mechanism and the pushrod and acting in a path dependent or direction-dependent manner. The second connecting device is thus preferably a controlled connecting device, that is, the pushrod follows the movement of the drive mechanism only when it is logical and required for the operation of the device. Preferably the second connecting device is controlled by the position of the container in relation to the housing, too.
The second connecting device is also very advantageously adapted to produce a unidirectional, positive connection between the drive mechanism and the pushrod when the drive mechanism is moved in the proximal direction and to move the pushrod along with the drive mechanism in the proximal direction and to convert a movement of the drive mechanism in the distal direction into a corresponding movement of the pushrod in the distal direction as long as the pushrod is not prevented from moving in the distal direction. This has turned out to be very advantageous for the operation of the device, and a relative movement between the drive mechanism and pushrod permits a simple adjustment of the dosage to be injected.
Also, in a proximal position region of the container, the second connecting device advantageously produces a connection between the drive mechanism and the pushrod in both the proximal and the distal direction. After an injection, this makes it possible to bring the container into its distal end position.
A further advantageous embodiment of the second drive connection is characterized in that in a distal position region of the container, this second drive connection produces a connection between the drive mechanism and the pushrod, which is effective in the proximal direction and permits the drive mechanism to move in the distal direction relative to the pushrod. After the distal end position of the container is reached, this makes it possible to displace the drive mechanism in the distal direction relative to the pushrod and in this way, to set an injection dosage since the combined length of the drive mechanism and the pushrod will increase as a result.
A fully automatic injection is permitted in a simple manner with such an injection device wherein the drive mechanism is associated with a spring and a detent mechanism; the spring, which in particular is a spring made of plastic material, acts on the drive mechanism in the proximal direction and can be compressed by sliding the detent mechanism in the distal direction where the detent mechanism engages when it reaches a predetermined cocked position. In its cocked position, the spring thus permits a fully automatic injection process via the second and the first connecting device. Because of the energy stored in this spring after being compressed, first a needle connected to the container is inserted and then the fluid is expelled from the container and injected. This permits the manufacture of a very simple, fully-automatic injector made of few parts. However, a device of this kind can also be actuated manually, that is, without a spring, wherein the user first inserts the needle by actuating a single actuation member and then injects the fluid in the set quantity.
In a very simple embodiment, the pushrod is formed, at least in some regions, in the form of a toothed rod. Such a toothed rod is easy and cheap to make, e.g., out of synthetic material. The teeth of the toothed rod are advantageously formed so that they only permit a movement of the toothed rod in the proximal direction in relation to a resilient detent mechanism. The pushrod is also advantageously associated with an abutment which at least limits its proximal movement in relation to the housing. By means of this, the user can see it when the fluid quantity in the container has been used up, or in this case, the device prevents further i

Affiliated with

Also associated with

Rating

Injection device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Injection device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Injection device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2519130