SE541186C2 - Suppository inserter - Google Patents

Abstract

The present invention relates to a device (1) for insertion of a suppository comprising a body (2), a piston (6) slidably inserted in the body, and a top section (4) having an opening (8) for receiving a suppository and including a tubular part (9) defining a cavity (28) and having a first end (30) for receiving the suppository and a second end (32) for receiving the piston. The body comprises a pressure generating section for generating a pressure on the piston to achieve a reciprocal movement of the piston between a first withdrawn position and a second extended position. The top section comprises a cover (5) attached to the tubular part, and the cover is removably attached to the body.

Description

Suppository inserter Field of the invention The present invention relates to a suppository inserter for inserting suppositories into body cavities.

Background of the invention In the medical care industry as well as in home treatment, there are numerous different ways by which a medicine can be applied to a patient. For instance, medicine can be administered by swallowing, injecting, inhaling or inserting into a body cavity. When the medication is needed to penetrate into and gradually be absorbed by the body, suppositories which can be introduced into an appropriate body cavity have been especially efficient. In particular, rectal suppositories have been used in order to administer a predetermined drug dosage to treat a variety of diseases and symptoms in a variety of patient populations. Certain medical conditions, such as digestive disorders, may be more efficiently treated when the suppository is placed in a particular location of the patient's anal canal or rectum.

When suppositories are applied in the health care, physicians many times use manual applications to aid in inserting the suppository into the body cavity. This application is preferable because suppositories provide a reliable, safe and hygienic means for controlling the insertion. In addition, suppository applications enable a patient to conveniently use them for self-insertion even when a doctor is not present. To accomplish their purpose, most suppositories typically constitute of a tubular body which holds the suppository whereas a piston or plunger is manually applied through the tube to push and insert the medication into the passage of the cavity. In clinical practice, sanitary applicators made of plastic materials are employed with increasing frequency. These medical aids are predominantly intended for a single use, and the procedures with them are conducted under either sterile or unsterile conditions. The most prevalently applied devices are, for instance, sterile hypodermic plastic single-use syringes.

However, there is a problem when suppositories are applied outside the health care and hospitals by unexperienced persons and in home environments. For example, when parents are about to insert suppositories into their children in order to reduce a fever. It is confusing how to introduce the suppository into the children. This results in that several parents change to liquid or tablet form, even though this does not always work or has poorer effect on the fever. The confusion prevails among other things, which end of the suppository is to be inserted first, the blunt end or the pointed end, how to hold the suppository, and howto insert it far enough to avoid irritating the intestinal and to avoid that the suppository comes out before it has been completely dissolved.

From US 3823715 it is known that an introducer for suppositories is devised as a syringe and has a tubular body with a forward necked-down inserting section and a rear, pressuregenerating section in the form of a cylinder within which there reciprocates a pressuregenerating piston. The forward end of the piston is extended into a forward portion having a smaller, effective diameter, such forward section fitting within the necked-down inserting section of the body.

From US 4990136 (A) it is known that a suppository applicator comprising a tubular body with an open and a closed end is devised to insert suppositories into body cavities. A plunger is slidably disposed in the tubular body for reciprocal movement between a withdrawn position and an extended position. Unfortunately, this kind of mechanically-driven syringe is way too complex, it is complicated and expensive to manufacture and is thus cost-inefficient.

Another example of suppository appliance is shown in DE1566679 (A1). This is a one-piece device made of elastic material comprised in one module. The front part with a piston has an opening to receive the suppository and the rear part is balloon-shaped. In order to eject the suppository, the rear part has to be pressed. Due to its elasticity the rear part is compressed, which causes the piston to be moving toward the opening and by that the suppository is ejected.

The disadvantage with all the three above-mentioned modifications of suppository techniques is that they are all produced for a certain size of suppository and today we have in general a lot of diverse sizes of suppositories manufactured by different suppliers. This creates inconvenience while a different suppository size must be used.

Object and summary of the invention It is an object of the present invention to at least partly overcome the above problems, and to provide an improved device for insertion of a suppository.

This object is achieved by a device as defined in claim 1.

The device comprises a body, a piston slidably inserted in the body, and an top section having an opening for receiving a suppository and including a tubular part defining a cavity having a first end for receiving the suppository and a second end for receiving the piston, and the body comprises a pressure generating section for generating a pressure on the piston to achieve a reciprocal movement of the piston between a first withdrawn position and a second extended position. The invention is characterized in that the top section is removably attached to the body. The top section comprises a cover attached to the tubular part and the cover is removably attached to the body.

According to the invention, the top section is removably attached to the body. Due to the fact that the cover is removably attached to the intermediate part, instead of the tubular part being removably attached to the body, the design and position of the tubular part can be varied without the need of changing the length of the piston or the size of the body. Accordingly the size of the cavity for receiving a suppository can be varied so that it is adapted to the size of the suppository. The same body and the same piston can be used for different sizes of suppositories. The only part that has to be changed is the top section. Thus there is a great flexibility achieved, because different sizes of suppository can be used with one and the same device, according to the invention.

Both the position and the size of the tubular part can be adjusted to the suppository size. The cover is attached to the body and is enabled to be made of different lengths.

The body and the cover is provided with attachment means adapted to cooperate with each other to allow the cover to be removably attached to the body. Examples of suitable attachment means are snap-fittings, and bayonet fittings.

According to an embodiment of the invention, the body comprises a plurality of replaceable top sections designed for receiving suppositories of different sizes. For example, each of the top sections has a cover with a length that differs from the length of the covers of the other top sections. For example, the inner diameters of the tubular parts may have different sizes. An apparent advantage is that the replaceable top sections make it possible to adapt to different sizes of suppositories. Owing to the fact that the cover and the body is provided with attachment means to removably attach the covertothe body, there could be designed tubular parts and covers in different sizes depending on the suppositories size. The suppository inserter is thus very cost-effective. This in contrast to having specific devices for each specific suppository size. It is to be appreciated that the distance between an upper part of the piston and the first end of the tubular part can be varied depending on the type of suppository. As it will be appreciated by ordinary consumer, suppositories vary in size and shape depending on their intended use and the particular manufacturer. Besides, the present applicator is not for a single use as the replaceable top sections are changeable while the main inserter is the same.

According to an embodiment of the invention, the cover is arranged to surround the tubular part and the cover is coaxially arranged with the tubular part. Suitably, the cover is attached to an upper portion of the tubular part.

According to an embodiment of the invention, the cover is conically shaped and arranged coaxially with the tubular part, and the cover is tapering towards the opening of the top section. The cover surrounds the tubular part that is disposed along an axis of symmetry of the cover. Due to the conical shape, the risk for injuring the baby during the insertion of the suppository is eliminated.

According to an embodiment of the invention, the second end of the tubular part protrudes below a lower end of the cover.

According to an embodiment of the invention, the piston comprises a piston head and a piston rod including a front portion and a rear portion. Each of the piston head and the piston rod has a smaller radial width than the tubular part so that the piston head and the front portion are slidably fitted in the tubular part. The rear portion has a larger radial width than the second end of the tubular part so that the rear portion is prevented from being inserted into the tubular part. The total length of the front portion and the piston head is larger than the length of the tubular part so that at least a part of the piston head will protrude from the tubular part when the piston is in the second extended position. With a radial width of the piston is meant the largest width of the piston in a radial direction. For example, the rear portion is provided with projections protruding in a radial direction and the radial width of the projections is larger than an inner diameter of the tubular part and thus preventing the rear portion from being inserted into the tubular part. Thus, the sliding movement of the piston is stopped when the rear portion of the piston is in contact with the second end of the tubular part. Due to the fact that a part of the piston head protrudes from the top section when the sliding movement of the piston is stopped, the distance the suppository is inserted in the body cavity is always the same and can be adapted to a suitable distance long enough to ensure that the suppository will stay in the body cavity until the suppository has been completely dissolved. The rear portion of the piston and the second end of the tubular part cooperate to stop the sliding movement of the piston towards the insertion opening when the piston head is protruding a defined distance from the top section.

According to an embodiment of the invention, the piston head protrudes at least 5 mm and preferably at least 7 mm from the top section when the piston is in the second extended position. With manually applied force, for example through an operating button, the piston ejects the suppository at a minimum of 5 mm, preferably 7 mm and thus it is guaranteed that the suppository will be ejected long enough to ensure that the suppository will stay in the body cavity until the suppository has been completely dissolved. Preferably, the piston head protrudes less than 12 mm from the top section. Thus, it is ensured that the suppository is not inserted too long in the body cavity.

According to an embodiment of the invention, the piston head is cylindrical and a diameter of the piston head is at least 10% smaller than an inner diameter of the tubular part. Preferably, the diameter of the piston head is at least 30% smaller than the inner diameter of the tubular part. Thus, the width of the piston head is substantially smaller than the width of the suppository. This design prevents injuring of the human body while operating with the suppository inserter to insert suppository into the body cavity.

According to an embodiment of the invention, the body comprises an intermediate section having a rear end attached to the pressure generating section and a front end removably attached to the cover of the top section, and device comprises a tubular guiding member for guiding the piston, wherein the guiding member is disposed inside the intermediate section and arranged coaxial with the tubular part of the top section, and the piston being slidably inserted in the guiding member. The guiding member is designed to house and guide the piston towards the tubular part of the top section.

According to an embodiment of the invention, the guiding member has a larger diameter than the tubular part, and an upper end of the guiding member is designed to receive the second end of the tubular part. When the top section is attached to the body, the second end of the tubular part is inserted in the upper end of the guiding member. By that the tubular part and the guiding member form a passage for the piston towards the insertion opening.

According to an embodiment of the invention, a wall of the pressure generating section is made of a resilient material and an outer end of the piston rod is connected to the wall. Suitably, the outer end of the piston rod is removably connected to the wall. Due to the resilient material, the wall of the pressure generating section can by compressed when the piston is moved to the second extended position. Preferably, the wall is made of material such as washable and durable soft plastic, which is of sufficient strength to house the piston of the suppository inserter. The sliding of the piston both inwardly and outwardly of the body of the inserter is possible as a result of elastic deformation of the resilient material of the wall.

According to an embodiment of the invention, an operating button is attached to an outer end of the piston rod and disposed on the outside of said wall. The operating button is used to manually move the piston towards the insertion opening and by that eject the suppository.

According to an embodiment of the invention, the operating button is disc shaped and the wall of the pressure generating section is provided with an opening for receiving the piston rod, and a diameter of the operating button is larger than a diameter of the opening in the wall. By that the piston can be inserted into and removed from the pressure generating section through the opening in the wall.

Brief description of the drawings The invention will now be explained more closely by the description of different embodiments of the invention and with reference to the appended figures.

Fig. 1 shows a perspective view of a suppository inserter according to an embodiment of the invention.

Fig. 2 shows a cross-sectional view of the suppository inserter shown in figure 1, with the piston in its withdrawn position.

Fig. 3 shows a cross-sectional view of the suppository inserter shown in figure 1, with the piston in its extended position and ejecting a suppository.

Fig. 4 shows a perspective view of a top section of the suppository inserter.

Fig. 5 shows a perspective view of the body with the top section removed.

Fig. 6 shows a perspective view of a piston.

Fig. 7a shows a view of the top section together with the piston in its withdrawn position. Fig. 7b shows a view of the top section together with the piston in its extended position. Fig. 8 shows examples of replaceable top sections.

Figs. 9a-b show the suppository inserter with different top sections.

Detailed description of preferred embodiments of the invention Referring primarily to figure 1, a device for insertion of a suppository, in the following named suppository inserter 1, according to an embodiment the present invention is displayed. As seen in figure 1, the suppository inserter 1 comprises a body 2 and a top section 4 having an insertion opening 8 for receiving a suppository. The top section 4 is removably attached to the body 2. The top section 4 comprises a cover 5 removably attached to the body. The body 2 comprises a pressure generating section 12. In this embodiment, the body further comprises an intermediate section 10. The intermediate section 10 has a rear end 14 attached to the pressure generating section 12 and a front end 16 removably attached to the cover 5 of the top section 4. The suppository inserter 1 is conically shaped and is tapering towards the insertion opening 8. The body 2 is rotationally symmetric and is tapering towards the top section 4. The cover 5 is conically shaped and is tapering towards the insertion opening 8. The pressure generating section 12 has a wall 20 made of a resilient material, such as a soft plastic material or fabric. The cover 5 and the intermediate section 10 are made of a non-elastic material, such as a hard plastic material. The suppository inserter 1 comprises an operating button 22 for ejecting the suppository. The intermediate section 10 is provided with gripping means in the form of two recesses 24 disposed on opposite sides of the body 2.

Figures 2 and 3 show cross-sections through the suppository inserter shown in figure 1. Figure 2 shows the suppository inserter in a withdrawn position and figure 3 shows the suppository inserter in an extended position. In the figures, the same and corresponding functional parts are designated by the same reference numerals. As seen from the figures 2 and 3, the body 2 is hollow and constitutes a housing of the suppository inserter 1. The suppository inserter 1 further comprises a piston 6 slidably inserted in the body 2 and movable between a first withdrawn position, as shown in figure 2, and a second extended position, as shown in figure 3. The pressure generating section 12 is designed for generating a pressure on the piston 6 to achieve a reciprocal movement of the piston 6 between the first withdrawn position and the second extended position. As shown in figure 3, the piston head protrudes a distance L3 from the insertion opening 8 of top section 4 when the piston 6 is in the second extended position. Preferably, the distance L3 is between 5 mm and 12 mm, more preferably the distance L3 is between 7 mm and 12 mm. For example, the distance L3 is 9 mm.

Figure 4 shows the top section 4 in more details. The top section 4 comprises the cover 5 and a tubular part 9 attached to the cover and extending inside the cover along an axis of symmetry of the cover. The cover 5 is conically shaped and arranged coaxial with the tubular part 9, and the cover 5 is tapering towards the first end of the tubular part 9. In this embodiment the tubular part 9 is circular cylindrical with an even inner diameter dl. However, in another embodiment, the tubular part can have different diameters along its length. For example, the diameter of the second end 32 of the tubular part can be less than the diameter of the first end 30 of the tubular part. The tubular part 9 defines a cavity 28 for housing the suppository. The tubular part 9 has a first end 30 for receiving the suppository and a second end 32 for receiving the piston 6. The first end 30 of the tubular part includes the insertion opening 8. As seen from figure 2, the second end 32 of the tubular part extends into the body 2. The tubular part 9 is surrounded by the cover 5. The tubular part 9 and the cover 5 are coaxial. The cover 5 is provided with attachment means 33 adapted to cooperate with corresponding attachment means of the body to allow the cover to be removably attached to the body. In this example, the attachment means 33 of the cover is an inwardly protruding flange surrounding a rear end of the cover. Examples of suitable attachment means are snapfittings, and bayonet fittings. The cover 5 is removably attached to the front end 16 of the intermediate section 10 of the body.

Figure 5 shows a perspective view of the suppository inserter with the top section removed. The front end 16 of the intermediate part 10 of the body is provided with attachment means 34 adapted to cooperate with the attachment means 33 of the cover. In this example, the attachment means 33 of the body is a plurality of snap fittings arranged along a periphery of an opening of the front end 16 of the intermediate section 10.

Figure 6 shows the piston 6 in more details. The piston 6 includes a piston head 40 and a piston rod 42. The piston head 40 has a smaller radial width wl than a diameter dl of the tubular part 9 so that the piston head is movable inside the tubular part. The piston rod 42 includes a front portion 44 having a smaller radial width w2 than the inner diameter dl of the tubular part 9 so that the front portion 44 is slidably fitted inside the tubular part, and a rear portion 46 having a larger radial width w3 than the second end 32 of the tubular part 9 so that the rear portion 46 is prevented from being inserted into the tubular part 9. Thus, the second end 32 of the tubular part 9 defines a stop for a forward movement of the piston. When the rear portion 46 of the piston has reached the second end 32 of the tubular part 9, the piston has reached the second extracted position as shown in figure 3. The total length L2 of the front portion 44 and the piston head 40 is larger than the length LI of the tubular part 9 so that at least a part L3 of the piston head 40 will protrude from the tubular part 9 when the piston 6 is in the second extended position, as shown in figure 3. The radial width wl of the piston head is at least 10% smaller, preferably and at least 20% smaller than the diameter dl of the second end of the tubular part. Thus, the radial width wl of the piston head is smaller than the diameter of the suppository. A front edge of the rear portion 46 of the piston forms a shoulder 48 adapted to be in contact with an outer edge of the second end 32 of the tubular part.

In this embodiment, the piston 6 comprises four wings 47 made in the form of a cross, disposed at right angles with respect to each other and extending along the length of the piston. The radial heights of the wings 47 are different in the piston head 40, the front portion 44, and the rear portion 46 of the piston. The radial height of the wings in the rear portion 46 is larger than the radial height of the wings in the front portion 44, and the radial height of the wings in the front portion 44 is larger than the radial height of the wings of the piston head 40. The front edges of the wings of the rear portion 46 of the piston form shoulders 48 adapted to be in contact with an outer edge of the second end 32 of the tubular part.

The piston further comprises a cylindrical part 50 disposed at the end of the front portion 44 and adjacent to the piston head. The cylindrical part 50 has a diameter that is slightly less than the inner diameter dl of the second end of tubular part to enable a smooth gliding movement of the piston in the tubular part. In this embodiment, the piston head comprised four wings arranged so that the piston head has a cruciform cross section. In an alternative embodiment, the piston head can be cylindrical with a circular cross section. In an alternative embodiment, the piston rod can be cylindrical with a circular cross section.

The operating button 22 is attached to an outer end of the piston rod 42 and disposed on the outside of the wall 20 of the pressure generating section 12, as shown in figure 2. The operating button 22 is used to manually move the piston towards the insertion opening and by that eject the suppository. In this embodiment, the operating button 22 is disc shaped. The wall 20 of the pressure generating section 12 is provided with an opening (not shown) for receiving the piston rod 42. The diameter of the operating button 22 is larger than the diameter of the opening in the wall 20. By that the piston can be entered into and removed from the pressure generating section 12 through the opening in the wall 20. The outer end of the piston rod 42 is provided with a protruding stop element 52 arranged to prevent the piston 6 from leaving the body 2. The stop element 52 is neighboring the operating button 22. The diameter of the stop element 52 is largerthan the diameter of the opening in the wall 20. The operating button 22 and the stop element 52 are arranged on opposite sides of the wall 20. The stop element 52 prevents the piston 6 from sliding out of the body 2.

The suppository inserter 1 comprises a tubular guiding member 55 for guiding the piston 6 during its reciprocal movement. The guiding member 55 is disposed inside the intermediate section 10 and arranged coaxial with the tubular part 9 of the top section 4. The piston 6 is slidably inserted in the guiding member 55. The guiding member 55 is cylindrically shaped and it extends along the axis of symmetry of the body. The guiding member 55 has a larger inner diameter d2 than an outer diameter dl of the tubular part 9 so that the second end 32 of the tubular part can be inserted in the guiding member. An upper end of the guiding member is designed to receive the second end 32 of the tubular part.

In the following, the function of the suppository inserter 1 will be explained with reference to figures 2 and 3. As seen from figure 2, at least a part of the piston head 40 is inserted in the tubular part 9 and the cavity 28 is formed between the insertion opening 8 and the piston head 40 when the piston 6 is in the withdrawn position. A suppository 57 is inserted into the cavity 28 through the insertion opening 8 so that the suppository bear on the piston head 40, as shown in figure 2. When the suppository is to be ejected, the piston 6 is retracted to its withdrawn position, and the operating button 22 is manually applied or pushed so that the piston is moved towards the insertion opening 8. During the movements of the piston 6, the pressure generating section 12 is contracted as shown in figure 3. Due to its elasticity the pressure generating section of the body is compressed, which causes the piston to be moving toward the opening and by that the suppository is ejected. The piston 6 slides forward throughout the body 2 until the shoulder 48 of the rear portion 46 of the piston is in contact with the second end 32 of the tubular part 9 and the piston is in its extended position. The piston head 40 slides forward throughout the cavity 28 of the body 2 until it protrudes a distance L3 from the insertion opening 8 of top section 4 when the piston 6 is in the second extended position. The cylindrical part 50 of the piston guides the movement in the tubular part 9, and provides a more controlled linear force on the piston 6. The suppository placed in advance in the insertion opening 8 is ejected into the body cavity of the patient, while the inserter 1 is in its second extended position. The suppository is ejected through the insertion opening 8.

Figure 7a shows a view of the top section 4 together with the piston 6 in its withdrawn position. Figure 7b shows a view of the top section 4 together with the piston 6 in its extended position.

Figure 8 shows examples of replaceable top sections 4', 4" and 4"' designed for receiving suppositories of different sizes. The top sections includes covers 5', 5", and 5"' attachable to the body with attachment means 50. The covers 5' and 5" of the top sections 4' and 4" have different lengths, but the tubular parts 9 of the top sections 4' and 4" have the same length. The inner diameter of the tubular part 9"' of the top section 4"' differs from the inner diameter of the tubular parts 9 of the top sections 4' and 4". The replaceable top sections make it possible to adapt to different sizes of suppositories. Due to the fact that the cover and the body is provided with attachment means to removably attach the cover to the body, there could be designed tubular parts and covers in different sizes depending on the suppositories size. The distance between the upper part of the piston head 40 and the first end 30 of the tubular part can be varied depending on the type of suppository by adjusting the length of the cover while keeping the length of the tubular part. Accordingly, the length of the cavity 28 can be varied to adapt to a certain length of the suppository. The replaceable top sections 4', 4" and 4"' can be used together with one and the same body.

Figure 9a shows the piston 6 and the top section 4' attached to the body 2 (as shown in figure 2). Figure 9b shows the piston 6 and the top section 4" attached to the same body 2. As seen from the figures, the distances a1, a2 between the upper part of the piston head 40 and the insertion opening 8 differs for top sections 4' and 4" and accordingly the length of the cavity 28 differs. Further, the distances b1, b2 between the second end 32 of the tubular part and the shoulder 48 of the piston differs when different top sections 4', 4" are attached to the same body. Thus, the distance the piston head 40 is moved differs due to the design of the different top sections 4', 4".

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. For example, the shape of the body may vary. Other suitable attachment means can be used. The wings of the rear portion of the piston can, for example, be substituted by a cylindrical part having a larger diameter than the diameter of the second end of the tubular part to form a shoulder.

Claims (7)

Claims

1. A device (1) for insertion of a suppository comprising: - a body (2), - a piston (6) slidably inserted in the body and comprising a piston head (40) and a piston rod (42) including a rear portion (46), and a front portion (44), - a top section (4) removably attached to the body, having an insertion opening (8) for receiving a suppository and including a tubular part (9) defining a cavity (28) and having a first end (30) for receiving the suppository and a second end (32) for receiving the piston (6), wherein the front portion (44) of the piston rod has a smaller radial width than the tubular part (9) so that the front portion is slidably fitted in the tubular part, and the body (2) comprises a pressure generating section (12) for generating a pressure on the piston (6) to achieve a reciprocal movement of the piston between a first withdrawn position and a second extended position, characterized in that the top section comprises a conically shaped cover (5) attached to the tubular part (9) and arranged coaxial with the tubular part (9), the tubular part is extending inside the cover along an axis of symmetry of the cover, and the cover is tapering towards the first end (30) of the tubular part, wherein the cover (5) is provided with attachment means (33) adapted to cooperate with corresponding attachment means (34) of the body (2) to allow the cover to be removably attached to the body, and the rear portion (46) of the piston rod has a larger radial width than the second end (32) of the tubular part (9) so that the rear portion is prevented from being inserted into the tubular part, and the length of the front portion (44) and the piston head (40) is larger than the length of the tubular part so that at least a part of the piston head will protrude from the tubular part when the piston (6) is in the second extended position.

2. The device according to claim 1, wherein a radial width (wl) of the piston head (40) is at least 10% smaller, preferably at least 20% smaller than the diameter (dl) of the second end (32) of the tubular part (9).

3. The device according to any of the claims 1-2, wherein the piston head (40) protrudes at least 5 mm from the top section (4) when the piston (6) is in the second extended position.

4. The device according to any of the previous claims, wherein the body (2) comprises an intermediate section (10) having a rear end (14) attached to the pressure generating section (12) and a front end (16) removably attached to the cover (5) of the top section (4), and the device comprises a tubular guiding member (55) for guiding the piston (6), wherein the guiding member is disposed inside the intermediate section (10) and arranged coaxial with the tubular part (9) of the top section (4), and the piston being slidably inserted in the guiding member (55).

5. The device according claim 4, wherein the tubular guiding member (55) has a larger diameter than the tubular part (9), and an upper end of the guiding member is designed to receive the second end (32) of the tubular part (9).

6. The device according to any of the previous claims, wherein a wall (20) of the pressure generating section (12) is made of a resilient material and an outer end of the piston rod (42) is connected to said wall.

7. The device according to claim 6, wherein the device comprises an operating button (22) attached to an outer end of the piston rod (42) and disposed on the outside of said wall (20).