MXPA99002374A - Dose display for an injection syringe - Google Patents

Abstract

An injection syringe comprising a housing accommodating an ampoule containing medicine sufficient for a number of dosed injections. The syringe has a dose setting mechanism by which doses may be set by rotating a dose setting element relative to the housing and the dose set is indicated on a scale. The scale is formed as a clock dial having a first part secured to the housing and a second part which is rotatable relative to the first part and which is coupled to the dose setting element, one of the parts carries the scale and the other carries an indicating member indicating a point on the scale. The angular distance between the divisions of the scale corresponds to the minute divisions on an ordinary clock. Holes are provided along the scale which holes can receive a pin forming a stop which cannot be passed by the indicating member.

Description

VISUAL INDICATOR OF THE DOSE FOR AN INJECTION SYRINGE Field of the Invention The invention relates to injection syringes of the kind comprising a housing accommodating an ampoule containing sufficient medicine for a number of dosage injections, the syringe has a mechanism of dose adjustment by means of which the doses can be fixed from injection to injection by rotating an element for adjusting the dose in relation to the housing, the size of the dose adjusted is indicated on a scale.

Background of the Technique A problem with the scales is that the perimeter of the syringe is adjusted to a limit with respect to the size of the scale and the digits on it. Especially where the syringe is used by people with impaired eyesight, as can often be the case with diabetics, a system that allows the use of larger digits R? F.029661 on the scale is desirable. Additional indications of the size of the adjustment dose can be obtained by studying the distance at which an injection button is raised from the syringe but when the pro unit elevation is very small, sometimes of the order of 0.15 mm, this will only cause an impression imprecise of the size of dose adjustment. It is an object of the invention to provide a syringe by means of which these limitations are overcome. This is obtained by a syringe of the kind mentioned at the beginning of this specification, such a syringe according to the invention is characterized in that the scale is formed as a quadrant having a first part fixed or secured to the housing and a second part which is rotating in relation to the first part and to which the dose adjusting element is coupled, one of the parts bears the scale and the other carries an indicating element indicating a point on the scale. When the dose indicating means are formed as a quadrant, this quadrant can be made arbitrarily large and the size limited only by the fact that the device must not be too bulky and must be acceptable from a design point of view. The second part of the dose indicating means may be coupled to the dose adjustment element by means of a gear mechanism. This may be necessary because the relative rotation of the dose adjusting means can be carried out around the longitudinal axis of the syringe while the dial is positioned so that the relative rotation of the first and second portions is It performs around an axis perpendicular to the longitudinal axis of the syringe, however, the coupling or gear adapters can also be used in syringes wherein the dial and the dose adjustment means rotate about parallel axes. The engaged coupling or adapter can also be used to obtain that the relative angular rotation of the first and second part of the dose indicating means may be larger than the relative rotation of the dose adjustment elements. As in hourglasses, a scale that carries divisions and digits can be arranged or placed along the perimeter of the quadrant with a pointer on the part that does not carry the divisions and the digits that point to a point on the scale that indicates the relative rotational position of the dose adjustment element and the housing and consequently the adjustment of the dose by this rotation. According to the invention, the syringe may appropriately be of the type that uses a flexible plunger rod to reduce the overall length of the syringe by deflecting the piston rod where it projects from the vial. Instead of the ordinary pen form, this type of syringe has a more parallelepiped shape with wide side walls suitable as carriers of the quadrants. According to one embodiment of the invention, a finger grip can be provided by following a diameter on the second part of the dose indicating means., the handle for the finger that is parallel with the longitudinal axis of the syringe when no dose is adjusted. This finger grip can be used to adjust a dose when the rotation of the second part is transmitted to the rotating dose adjusting element through the coupling between the second part and the dose adjustment element. The finger grip will indicate conspicuously whether a dose is fixed or not, even if a small deviation from the position in the axial direction of the syringe is recognizable.

According to a further embodiment of the invention, the angular distance between the divisions of the scale is 6o corresponding to the minute divisions of an ordinary clock. This makes it possible for the user to estimate the setting even when he can not see the digits of the scale. This is due to the fact that the quadrant is so well recognized that most people can read the time on a quadrant without digits, and of course also on a quadrant without divisions. Therefore the position of the indicator element in relation to the scale alone, will let the user know the size of an adjustment dose. DE 42 08 677 discloses a pen-shaped injection device having a dose adjustment mechanism which can be operated by means of a dose adjustment element. When not in use, the syringe is stored in a box having a dose adjustment device comprising a large quadrant scale with divisions and impressions. When the syringe is stored in the box, a dose can be adjusted by operating the dose adjustment device on the box and the movements of this device are by means of a gear mechanism transmitted to the dose adjustment element of the syringe .

In the device according to the invention, the clearly visible dial is carried by the injection device itself so that no adjustment can be made which is not shown on the dial. Still the device can be designed so that the indication on the marker is successively returned to zero during the injection so that the indication on the dial usually shows the dose which remains for it to be injected. The injection syringe may have means by which the adjustment movement of the dose setting element is limited so that an upper limit is set with respect to the dose which can be adjusted or set. If by adjustment of the dose a dose adjustment element is moved until it is stopped by a stop, a fixed dose is adjusted. According to an embodiment of the injection syringe according to the invention, the limit can be provided by holes provided along the scale, such holes can each receive a pin forming a stop or stop which can not be passed through the indication element. This makes it possible to place a limit on the dose which can be adjusted because the second part can only be rotated until the indicator element reaches the point on the scale where a bolt is inserted into the hole. The bolt can be installed by a user which mostly uses the same dose in each injection. When the bolt is adjusted in the hole in the division corresponding to the dose in question, the user can adjust the dose by rotating the second part until the rotation is stopped because the bolt reaches a stop or stop which prevents that it passes the indicator element. Alternatively the bolt can be assembled by medical practitioners to ensure that the user will not inject more than a limited number of units in an injection. The bolts used can be designed so that a tool is necessary to install or remove them. Especially when the device is used by children it is important that an upper limit can be adjusted for the dose which can be injected. In the following the invention will be described in further detail with reference to the drawings, wherein Figure 1 shows a pen-shaped syringe with a display or visual indicator according to the invention, Figure 2 shows a new short syringe designed with a display or visual indicator according to the invention, Figure 3 shows a mode of a display or visual indicator according to the invention, and Figure 4 shows another embodiment of a display or visual indicator according to the invention.

Detailed description of the invention In Figure 1 a pen-shaped syringe comprising a housing 1 containing a dose adjustment mechanism, a cap 2 protecting the needle end of the syringe is shown, such cap is provided with a clip or clip 3 by means of which the syringe can be carried in a pocket in a manner similar to a fountain pen, and an injection button 4 which is raised from the end of the housing 1 concurrently with the adjustment of a dose and which can be depressed back to the embedment or butt contact with the end of the housing to inject the adjustment dose.

In addition, the syringe carries a screen or visual indicator that has the shape of an hourglass dial. The visual indicator or screen comprises a scale 5 which bears equidistant marks corresponding to the minute marks on an ordinary clock dial. The scale 5 is fixed to the housing 1. A pointer is established by a circular plate 6 that carries a handle for the finger 7 having an arrow mark 8. The circular plate 6 and the finger grip 7 form a dose adjustment unit by means of which a dose can be adjusted by holding the finger grip 7 and rotating plate 6 clockwise until the arrow mark points on the scale mark indicating the desired dose. The plate 6 with the finger grip 7 is mounted on an axis not shown which is hinged in the housing and through which, combined with a gear mechanism, the rotation of the dose adjustment unit is transmitted to a conventional dose adjustment mechanism in the housing 1. The plate 6 can be omitted so that the dose adjusting unit comprises only the finger grip 7. The modality shown in Figure 2 represents another type of syringe. which due to the use of a flexible plunger rod, are made shorter than those of the jib type. The pen comprises a housing 11 containing a dose mechanism and accommodating a cartridge with a medicine to be delivered. An injection needle 12 is mounted on a hub 13 of the needle, which can be screwed onto the syringe. The end of the syringe that carries the needle can be covered by a protective cap not shown. The syringe has an injection button 14 which is raised from the end of the housing 11 concurrently with the adjustment of a dose and which can be depressed again until the embedment or butt contact with the end of the housing to inject the adjustment dose . Also in this mode a scale 15 is fixed on the housing and the dose is adjusted by turning clockwise a dose adjusting unit comprising a circular plate 16 carrying a finger grip 17 with a finger. mark 18 of the arrow, until the point of the arrow mark points to the mark corresponding to the desired dose. This rotation is transmitted through an axis not shown that carries the dose adjustment unit and which transmits the rotation of this unit to a mechanism for adjusting the dose in the housing. The button 14 is pressed down to its base until the butt contact with the housing, to inject the adjustment dose and concomitantly with the injection, the dose adjustment unit is rotated back so that the mark of the arrow points to the zero mark of the scale to indicate that the full dose will be supplied. It takes advantage of the fact that the observation of a quadrant is so well promoted that most people will be able to estimate the minute number by observing the position of a mark along the periphery of a circle. Making the divisions which indicate the number of adjustment of the units of the medicine to be injected correspond to the divisions of minutes of a quadrant, the user will be able to estimate the size of an adjustment dose with high precision even when the size of the dose is not indicated by a number in each division mark. When, for example, only division marks are given every fifth with a number indicating the dose, the digit of this number can be made very large so that it can be easily read. To take full advantage of this fact, it is preferred that the finger grip be turned clockwise when a dose is adjusted. In Figure 3 where a scale 19 is carried by a circular plate 20 of a dose adjustment unit which can be rotated by a finger grip 21 and the arrow mark 22 is fixed relative to the housing, this clockwise rotation is obtained by placing the scale marks and the scale numbers in a counterclockwise mode. In this way, a clockwise rotation of the dose adjustment unit will bring increasing numbers at the same level as the arrow mark. In Figure 3 the scale has a broad mark 28 which can be pointed by the arrow when the finger grip is rotated in the counterclockwise direction. A stop or detent is set so that the scale is only rotated further in the counterclockwise direction until the arrow points to the mark 28. By this rotation in the counterclockwise direction, a fixed small dose, corresponding for example to the 10 μl supply of the medicine. This small dose is adjusted before the dose to be injected is adjusted and is applied by pressing the injection button. Therefore, the air in the bulb and / or the needle is removed by the application of pressure through the needle and a visual inspection of the jet at the end of the needle can reveal if the air is expelled. The adjustment for rotation in the counterclockwise direction of the finger grip and the subsequent pressing of the injection button is repeated until a jet of liquid is observed at the end of the needle. The provision of the possibility of adjusting a small dose by rotating in the counterclockwise direction of the finger grip, can be observed as a feature that facilitates the air injection procedure which must also be effected by the repetitive adjustment of small doses in the conventional manner by turning the finger grip clockwise. In Figure 4 another screen or visual indicator is shown with a scale 23 which is fixed in relation to the housing. The visual display or indicator carrying the scale 23 has a central part 24 which is also fixed relative to the housing and which at each mark of the scale indicating a unit of the medicine to be injected, has a hole 25. inside which a bolt not shown can be inserted. The dose adjustment unit only consists of a handle 26 for the finger with an arrow mark 27, such unit is carried by an axis not shown which transmits the rotation of the unit to a dose adjustment mechanism. Below the screen or visual indicator carrying the scale, the axis has a pointer parallel to the finger grip and pointing from the axis in the direction of the arrow mark. When a bolt is mounted in one of the holes in the display or visual indicator, the pointer will make butt contact with this bolt when the dose adjusting unit is rotated and will prevent further rotation in the direction of dose adjustment, but it will allow the return when a dose of adjustment is injected. This way can be ensured so that a maximum dose of adjustment is not exceeded. It also shows that the dose mark does not have to be numbered in every 5 units, but for example in every 15 units. Indeed, most of the known designs of hourglasses and similar watches can be used without departing from the scope of the invention.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following

Claims (6)

1. A syringe for injection, which comprises a housing accommodating a vial containing sufficient medicine for a number of metered injections, the syringe has a dose adjustment mechanism by means of which the doses can be adjusted by rotating an adjusting element of the dose in relation to the accommodation and the adjustment of the dose is indicated on a scale, which is formed as a quadrant on which an indication element aims to show the adjustment dose, these elements, the scale and the indication element , they are rotatable with each other, characterized in that one of the elements is integral with the housing and the other is coupled to the dose adjustment element of the syringe.

2. A syringe for injection according to claim 1, characterized in that the element which is not integral with the housing is coupled to the dose adjustment element through a gear mechanism.

3. A syringe for injection according to any of claims 1 or 2, characterized in that a finger grip is provided on the element which is not integral with the housing, such grip follows a diameter parallel to the axis of the syringe when no dose is adjusted.

4. A syringe for injection according to any of the preceding claims, characterized in that the angular distances between the divisions of the scale are 6o corresponding to the small or minute divisions on an ordinary clock dial.

5. A syringe for injection according to any of the preceding claims, characterized in that it has means by which the adjustment movement of the dose adjustment element is limited, so that an upper limit is set with respect to the dose. which can be adjusted.

6. A syringe for injection according to claim 5, characterized in that the holes are provided along the scale, such holes can receive a pin forming a stop or retainer which can not be passed through the indicator element.