WO2003061508A1

WO2003061508A1 - Applicator for liquid or viscous substances

Info

Publication number: WO2003061508A1
Application number: PCT/EP2003/000660
Authority: WO
Inventors: Rainer Hahn; Ulrich Prager
Original assignee: Dürr Dental GmbH & Co. KG
Priority date: 2002-01-23
Filing date: 2003-01-23
Publication date: 2003-07-31
Also published as: DE10202367A1

Abstract

Disclosed is an applicator for liquid or viscous substances, which is used particularly in medicine or dental medicine, comprising a conventional syringe body (2), in which a specific amount of the substance (12) is stored. The substance (12) is dispensed from the syringe body (10) to the desired location, e.g. in or at the tooth of a patient, via a dispensing hollow needle (26) by means of a displacing piston (11). Said displacing piston (11) is actuated by a force device (7) which is preferably arranged in an autonomous spring motor part (1) of the applicator. The flow path between the inside (1.0) of the syringe body (2) and the dispensing hollow needle (26) is controlled by a valve (15) which is connected to a manual actuating unit (19) positioned at the syringe body (2). The force device (7) exercises constant pressure on the displacing piston (11), but the substance (12) flows via the dispensing hollow needle (26) only when the valve (15) is open, whereby even minuscule quantities of the substance can be dispensed in precise doses without requiring a further flow of substance.

Description

Applicator for liquid or viscous substances

The invention relates to an applicator for liquid or viscous substances, in particular for use in the medical or dental field

a) a syringe body in which a certain amount of the substance can be introduced;

b) a displacement piston which is arranged displaceably within the syringe body;

c) a dispensing cannula arranged at one end of the syringe body, via which the substance can be pressed out of the interior of the syringe body;

d) a force device which applies the force necessary to displace it on the displacement piston.

In general in the medical field, but especially in the field of dentistry, there is always the task of precisely dosing a certain amount of a liquid or viscous substance at a certain point. to apply. Such liquid substances can contain active substances; In the dental field in particular, it can be aqueous acid solutions, low-viscosity plastics or the like.

Known applicators of the type mentioned at the outset are conventional syringes, in which the amount of the dispensed substance is released by finger pressure on the displacement piston. stamping is determined. When dispensing very small, well-defined cans, however, such syringes cause problems, since they not only require a very sensitive hand, but moreover, a certain reflow of the substance cannot be prevented after the pressure has already been removed from the displacement piston.

The object of the present invention is to design an applicator of the type mentioned in the introduction such that it can be used to apply very precisely defined, even very small, doses.

This object is achieved in that

e) a valve is provided in the flow path between the interior of the syringe body and the dispensing cannula.

In the applicator according to the invention, the start and the end of the flow are the ones to be applied

Substance no longer determined by the start and end of pressure on the displacer. Rather, the latter can be continuously subjected to force. Whether and how long the substance then flows out of the dispensing cannula depends solely on the length of time in which the valve is open or closed. The valve can be opened and closed at a very high speed because the moving parts have a very small mass. In this way it is possible to measure even the smallest doses in a well-defined manner.

The force device is expediently a spring which acts directly or indirectly on the displacement piston. The user of the application device according to the invention is therefore concerned with the force which moved the displacer no longer to take care of itself; this is always provided by the spring. The user can only pay attention to opening or closing the valve.

The embodiment of the applicator according to the invention in which the spring is accommodated in the housing of a spring motor part and acts there on a displaceable piston whose piston rod is led out of the housing of the spring motor part is particularly preferred, the spring motor part being detachably connected to the syringe body designed as a disposable cartridge part. This embodiment of the invention is particularly cost-effective since it represents an optimal division of disposable articles and applicator parts that can be used permanently: the spring motor part can be used again and again without time restrictions; the syringe body, on the other hand, is designed as a disposable part that is filled in the factory with a certain amount of the substance, which is sufficient for a certain number of applications, for example for 10 or 20 applications.

The spring motor part and cartridge part are advantageously connected to one another via a bayonet lock, so that removing a used cartridge part and replacing it with a brand-new, filled cartridge part is possible quickly.

For hygienic reasons it is recommended that the

Dispensing cannula is part of a disposable end cap which is releasably attached to the syringe body. This end cap is therefore changed with each individual application process or at the latest from patient to patient. The end cap can be locked onto the syringe body, which in turn enables quick and easy replacement.

It is advantageous if the end cap has at least one radially inwardly projecting catch which engages in an annular groove on the outer surface of the syringe body. In this way, the end cap can be rotated relative to the syringe body in order to change the direction of the dispensing cannula.

Removing the end cap from the syringe body is particularly easy in the embodiment of the invention in which the edge region of the end cap in the undeformed state lies hollow over a recess in the outer circumferential surface of the syringe body. By pressing on the hollow edge area, the locking lug can be lifted out of the annular groove in which it has previously engaged, so that the end cap can then be easily removed in the axial direction.

In a preferred exemplary embodiment of the invention, the valve comprises a rotatable valve plug, in which a flow-through recess is formed. This is a particularly problem-free, mechanically uncomplicated valve structure.

It is again advantageous if the throughflow recess of the valve plug is a groove with a depth that increases from one end to the other. This allows the valve to be opened and closed particularly sensitively.

It is useful if the throughflow recess of the valve plug is V-shaped in cross section. In this way, the respective open flow Adjust the cross sections of the valve very sensitively.

The valve plug can be connected via at least one swivel arm to a manual actuating element introduced on the syringe body. This is preferably a slide which is guided linearly on the outer circumference of the syringe body. This slide can be easily operated with a finger.

Finally, it is preferred if a spring is provided which presses the valve into the closed position. The user must therefore apply a force for as long as the valve is to remain open; if the user removes the force, the valve closes automatically.

An embodiment of the invention is explained below with reference to the drawing; show it

Figure 1 shows an applicator for dental purposes in axial section with removed

Cartridge part;

Figure 2 shows the applicator of Figure 1 in an operational state;

Figure 3 shows an enlargement of Figure 1;

Figure 4 on a different scale and schematically the valve plug used in the applicator of Figures 1 to 3;

5 shows an enlarged detail from FIG. 1 in the area of the valve plug, specifically in the closing direction thereof; Figure 6 shows a section, similar to Figure 5, but in an open position of the valve plug.

The applicator shown in the drawing is used in dental medicine to apply the smallest portions of substances, for example solutions containing active ingredients or plastic masses, on site, where precise dosing is important. The applicator comprises a spring motor part 1, a syringe body 2 designed as a cartridge part and an end cap 3.

The spring motor part 1 has a housing 4, which is composed of two housing parts 4a, 4b. The housing parts 4a, 4b are permanently connected to one another at the mutually facing edges, for example glued, welded or locked. In the interior of the housing 4, a piston 5 is slidably arranged, the piston rod 5a of which is designed through a stepped bore 6 at the upper end of the housing 4 in the drawing.

A compression spring 7, which is pushed over a spring holder 8 formed on the housing part 4a, is clamped between the bottom wall of the housing part 4a, which is shown in the drawing, and the piston 5, which is formed like an apron in this area. The compression spring 7 seeks to push the piston rod 5a as far as possible out of the upper housing part 4b of the spring motor part 1 in the drawing, as shown in FIG.

The area of the stepped bore 6 in the housing part 4b of the spring motor part 1 lying further up in the drawing is designed as part of a bayonet catch and has for this purpose an annular groove 9 formed in the lateral surface of the bore 6 and two not shown in the drawing, from the outer end to the annular groove 9 premier Axial grooves.

The cartridge part 2 is provided with a bore 10 which opens in the direction of the spring motor part 1 and which has a certain frictional force in the bore

10 seated, displaceable displacement piston 11 is closed and filled with the substance to be applied. On the outer periphery of the area adjacent to the spring motor part 1, two bayonet lugs 12, 13 are formed on the cartridge part 2, which are inserted into the aforementioned axial grooves of the spring motor part 1 and can be introduced into the annular groove 9 of the spring motor part 1 by turning such that the cartridge part 2 in the shown in Figure 2 is connected to the spring motor part 1.

In order to be able to connect the cartridge part 2 to the spring motor part 1 in the manner described, the piston rod 5a of the piston 5 of the spring motor part 1 must be pushed back against the action of the compression spring 7. For this purpose, the displacement piston 11 of the cartridge part lies down

2 on the outer end face of the piston rod 5a. Since the substance in the cartridge part 2 is largely incompressible and at this point in time cannot escape from the bore 10 of the cartridge part 2 at any other point, the spring 7 can be tensioned in this way.

The bottom of the bore 10 in the cartridge part 2 is tapered; this shape is complementary to the upward-facing end face of the displacer 11, which also tapers. A relatively narrow application channel 14 extends from the top point of the bottom of the bore 10 in the drawing to the upper end face of the cartridge part 2 in the drawing. A valve 15 is arranged in the application channel 14 as is in particular can be seen in Figure 3. The valve 15 comprises a rotatable valve plug 16, which is shown schematically in FIG. 4. The valve plug 16 has a throughflow recess 31 in the form of a groove in the outer surface of a cylindrical pivot 16a, which progressively becomes deeper from one end to the other. The pivot pin 16a is rotatably guided in a complementary bore 40 (see FIGS. 5 and 6) of the cartridge part 2. Depending on the rotational position of the valve plug 16 within the valve 15, a more or less large flow cross-section is released between the bore 10 and the application channel 14 of the cartridge part 2, as the comparison of FIGS. 5 and 6 makes clear. Due to the different depth of the groove 31, a very sensitive adjustment of the opening cross section is possible.

As can be seen from FIGS. 3 to 6, the valve plug 16 is connected to a swivel arm 17 which is integrally formed on a disk 16b which coaxially continues the pivot 16a and has a larger diameter. Disc 16b and swivel arm 17 are in the assembled state to the side of the cartridge body 2. The outer end of the swivel arm 17 engages from the inside in a scoop 20 molded onto a slide 19. The slider 19 is guided in a manner not shown here on the outer surface of the cartridge part 2, but is normally pressed down by a hidden compression spring 21, which is supported on a projection 22 of the cartridge part 2 in the drawing and moves on it Way the valve plug 16 normally in the closed position.

At the end opposite the scoop 20, the slider 19 has an elevation 23 similar in shape to the scoop 20, so that the area between the scoop 20 and the elevation 23 is well suited for the application of a finger, for example the thumb.

The end cap 3 is detachably snapped onto the end of the cartridge part 2 facing away from the spring motor part 1. The end cap 3 comprises an apron 24, which is cylindrical in the undeformed state, and a conically tapering end section 25, on which a delivery cannula 26 is molded.

Approximately at the transition between the cylindrical apron 24 and the conical end section 25 of the end cap 3, two locking lugs 27, 28 are cut out of the material of the end cap 3 and bent inwards, which engage in an annular groove 29 on the outer surface of the cartridge part 2. The outer surface of the cartridge part

2 is also provided in the region of the edge of the apron 24 of the end cap 3 with a further, wider annular groove 30, so that the end region of the apron 24 is hollow.

The applicator described above is used as follows:

The spring motor part 1 is a component that is used for a long time; the cartridge part 2 is a disposable part, which contains sufficient substance for a two-digit number of applications, while the end cap

3 is a disposable item that is disposed of after each treatment.

In order to make the applicator ready for operation, a new, filled cartridge part 2 is placed on the spring motor part 1 in the manner already described above, the compression spring 7 being tensioned. The substance in the bore 10 of the cartridge part 2 is now under Pressure, however, cannot escape from the bore 10 because of the closed valve 15.

For the respective patient, an end cap 3 is now snapped onto the upper end of the cartridge part 2 in FIGS. 1 to 3, the direction in which the dispensing cannula 26 extends can still be adjusted by rotating the end cap 3 relative to the cartridge part 2.

If the user now wishes to transfer a certain amount of the substance in the bore 10 to a location via the delivery cannula 26, e.g. to apply in a patient's tooth, he moves the slide 19 with the aid of a finger in FIGS. 1 to 3; as a result, the valve plug 16 is pivoted within the valve 15 via the pivot lever 17 until its groove 31 releases a flow cross section from the bore 10 to the application channel 14 of the cartridge part 2. The flow cross section can be due to the

Shape of the groove 31 in the valve plug 16 can be finely metered. Under the action of the compression spring 7, the displacement piston 11 of the cartridge part 2 is now moved forward, whereby the substance located in the bore 10 via the valve 15, the application channel 14 and the

Dispensing cannula 26 is expelled. If sufficient substance has escaped, the user removes the pressure from the slide 19, which immediately returns under the action of the spring 21 to the rest position in which the valve 15 is closed. In this way, an afterflow or dribble is reliably prevented. Exactly the amount of substance that is required is released.

When the treatment is finished, the end cap 3 approved in the following way:

By pressing on the edge region of the apron 24, which is pressed somewhat into the annular groove 30 of the cartridge part 2 in this way, the locking lugs 28, 29 of the end cap 3 move radially outward and thus come from the annular groove 29 of the cartridge part 2 free. The end cap 3 can now be pulled forward in the axial direction and replaced by a new end cap 3, which is then used for the next patient.

If the entire contents of a cartridge part 2 have been used up, this is replaced by a new, filled cartridge part 2.

If the housing 4 of the spring motor part 1 is made of transparent material and provided with a scale, the position of the spring piston 5 of the spring motor part 1 can be used to visualize the filling quantity of the cartridge part 2.

Claims

claims

1. Applicator for liquid or viscous substances, in particular for use in the medical or dental field, with

a) a syringe body in which a certain amount of the substance can be introduced;

d) a force device which applies the force required to displace it on the displacement piston,

characterized in that

e) a valve (15) is provided in the flow path between the interior (10) of the syringe body (2) and the dispensing cannula (26).

2. Applicator according to claim 1, characterized in that the force device (7) is a spring which acts directly or indirectly on the displacement piston (11)

3. Applicator according to claim 2, characterized in that the spring (7) in the housing (4) of a spring motor partly (1) and accommodates a displaceable piston (5), the piston rod (5a) of which is led out of the housing (4) of the spring motor part (1), the spring motor part (1) being detachable with the syringe body (disposable cartridge part) ( 2) is connected.

4. Applicator according to claim 3, characterized in that the spring motor part (1) and the cartridge part (2) via a bayonet lock (9, 12, 13) are interconnected.

5. Applicator according to one of the preceding claims, characterized in that the dispensing cannula (26) is part of a disposable end cap (3) which is releasably attached to the syringe body (2).

6. Applicator according to claim 5, characterized in that the end cap (3). On the syringe body (2) is locked.

7. Applicator according to claim 6, characterized in that the end cap (3) has at least one radially inwardly projecting locking lug (27, 28) which engages in an annular groove (29) on the outer surface of the syringe body (2).

8. Applicator according to claim 7, characterized in that the edge region of the end cap (3) in the undeformed state is hollow over a recess (30) of the outer surface of the syringe body (2).

9. Applicator according to one of the preceding claims, characterized in that the valve (15) comprises a rotatable valve plug (16) in which a through- flow recess (31) is formed.

10. Applicator according to claim 9, characterized in that the through-flow recess (31) of the valve plug (16) is a groove with increasing depth from one end to the other.

11. Applicator according to claim 9 or 10, characterized in that the through-flow recess (31) of the valve plug (16) is V-shaped in cross section.

12. Applicator according to one of claims 9 to 12, characterized in that the valve plug (16) via at least one swivel arm (17) with a syringe body (2) attached to the manual actuator (19) is connected.

13. Applicator according to claim 12, characterized in that the manual actuator is a on the outer circumference of the syringe body (2) linearly guided slide (19).

14. Applicator according to one of the preceding claims, characterized in that a spring (21) is provided which presses the valve (15) into the closed position.