HK1065973A - Expression device for a cartridge comprising two chambers arranged concentrically to each other - Google Patents

Description

Pushing device for a cartridge having two chambers arranged concentrically with respect to one another

The invention relates to a pushing device for a cartridge having two chambers arranged concentrically to one another and closed by a piston, according to the preamble of claim 1.

It is known to attach a cap, which has a threaded hole in its center, fixedly to the rear end of the cartridge opposite the outlet in order to push a cartridge having only one tubular chamber. A threaded spindle with a wing-shaped handle can be screwed into the threaded bore, the end face of the spindle bearing against a piston which closes the chamber and moves it in the reservoir in the direction of the outlet opening.

A pushing lance is known for emptying cartridges having two chambers arranged concentrically with respect to one another and closed by pistons, which has a pushing ram formed by a pressure plate and a pressure ram for each piston. Such a pusher gun is relatively expensive and is therefore generally used only by craftsmen who often handle such cartridges. It is therefore common for such cartridges to be provided as a separate product without a push gun.

A pushing device for a cartridge having two chambers arranged concentrically to one another is known from DE 29823237U 1, wherein the pushing ram pressing on the piston of the inner chamber is designed as a spindle. The piston is moved in the direction of the outlet opening of the reservoir by screwing the threaded spindle into a threaded hole in an axially closed cover on the rear side of the reservoir. By means of a plurality of pressure rods connected to the spindle and arranged through bores in the cover mounted on the rear side of the reservoir, the annular piston of the outer chamber is displaced axially simultaneously with the inner piston during the feed movement of the spindle. In order to apply a uniform pressure to the annular piston, at least three pressure rods are connected to each other at their ends by an annular fulcrum located on the pressure plate. The end of the pressure rod and the fulcrum can be connected only after the top cover is pushed away by the pressure rod and the inner material pushing rod. The cover thus forms a part with the pushing device, which requires a lock between the cover and the cartridge that can only be achieved by the user.

This known pushing device consists of a plurality of parts which are to be coordinated with one another, which on the one hand makes it more expensive to manufacture and on the other hand can be functionally problematic. The object of the invention is therefore to provide a pushing device which can be produced cost-effectively and has an increased functional reliability.

This object is achieved by the features of claim 1. In the pushing device according to the invention, the pushing ram is a one-piece component, preferably made of plastic by injection molding, with an inner leg which is pressed against the piston of the inner chamber of the reservoir and an outer tubular leg which is arranged coaxially with the inner leg and is pressed against the annular piston of the outer chamber. The feed movement of the pusher is achieved by a thread on the outer surface of the outer leg, which thread is arranged over the entire length of the outer leg. The external thread is screwed into an internal thread of a threaded ring which serves as a terminal member on the rear end of the outer chamber of the cartridge, for example by being clamped or adhesively secured. The thread has the largest possible diameter due to the arrangement of the thread on the outer surface of the outer support, which ensures a high pressing pressure with a low screwing torque and also allows a tilt-free guidance of the ram. The end faces of the inner and outer legs each form an annular abutment which, when the ram is screwed in, moves the piston in the direction of the reservoir outlet.

The pushing device according to the invention comprises an integral pushing ram and a threaded ring, which can also be produced from plastic by injection molding and which is preferably already installed in the outer chamber of the cartridge at the factory. The pusher can be produced cost-effectively, since it consists of only two parts and does not require assembly.

In order to save material when producing the stripper rod, the thread is preferably formed exclusively by a plurality of thread strips arranged in the longitudinal direction.

To improve guidance, it is preferable that: on the one hand, the thread is designed as a trapezoidal thread, and on the other hand, the thread ring has at least two helices.

For manual screwing in of the ejector pin, the ejector pin has a wing-shaped rotary knob at its rear end. An internal hexagon can be provided in addition to the twist grip to accommodate a corresponding tool for the mechanical screwing-in.

The drawings show an embodiment of the invention as follows:

FIG. 1: a perspective view of a cartridge with a pusher;

FIG. 2 is a longitudinal cross-sectional view of a cartridge having an ejector;

FIG. 3: a cross-sectional view of the threaded ring.

The cartridge 1 shown in fig. 1 and 2 is a two-component cartridge having two chambers 2, 3 arranged concentrically with respect to one another, one for each of the components. The inner chamber 2 is formed by an inner tube 4 and the outer annular chamber 3 by an outer tube 5. The outlet openings of the two chambers end in a cartridge opening 6, to which a static mixer 7 is fitted as shown in fig. 1, and a closure cap 8 is fitted in fig. 2. Both chambers 2, 3 are closed by pistons 9, 10, the piston 10 for the outer chamber 3 being annular. The volume of the chambers 2, 3 corresponds to the mixing ratio of the two components contained in the chambers. In order to achieve a homogeneous mixing of the components, the two pistons must therefore be moved uniformly in the direction of the cartridge outlet 6.

This is achieved by a push rod 11 which is screwed into a threaded ring 13 by means of a thread 12. Which is fitted at the rear end of the outer tube 5 of the cartridge 1. In order to fix the threaded ring 13, it is glued in the outer tube 5 in the embodiment shown. The threaded ring 13 shown in detail in fig. 3 has an internal thread 14 corresponding to the thread 12 of the stripper rod 11. In order to avoid skewing when the ram 11 is screwed into the threaded ring 13, the threaded ring 13 has at least two complete, preferably trapezoidal, threads. In order to facilitate the insertion of the threaded ring 13, a flange 15 is provided in the ring, which is located at the rear end of the outer tube 5. The ram 11 has an inner leg 16 which is supported on the piston 9 of the inner chamber 2 and an outer leg 17 which is supported on the annular piston 10 of the outer chamber 3. The two struts are tubular and are arranged coaxially to one another. At the rear end of the ram 11, which is formed by a base plate 18, a wing-shaped turning handle 19 is arranged, which can be screwed into the ram 11 manually. A socket 20 for receiving a corresponding tool for the mechanical screwing is arranged in the center of the rotary knob 19.

The ejector pins 11 are made in one piece from plastic by injection molding. In order to save material, the thread 12 is formed by a plurality of thread strips 21 arranged in the longitudinal direction. To prevent skewing during screwing in, at least three screw flights 21 are required. In the embodiment, four screw-thread strips are provided.

Depending on the amount of the components charged into the chambers 2, 3, the pistons 9, 10 are slightly offset from one another either in one height or, as in the exemplary embodiment shown. The end faces of the inner and outer legs 16, 17 are also in this case offset from each other by the same distance in order to move the two pistons axially simultaneously with each other.

Claims (7)

1. Pushing device for a cartridge (1) having two chambers (2, 3) arranged concentrically to one another and closed by pistons (9, 10), wherein the pushing device consists of a pushing ram (11) with a thread (12) which can be moved axially in the direction of the cartridge outlet (6) by screwing into an end piece which is arranged at the rear end of the cartridge (1) and has an internal thread (14), characterized in that the pushing ram (11) has an inner leg (16) which bears against the piston (9) of the inner chamber (2) and an outer tubular leg (17) which is arranged concentrically to the inner leg and bears against the annular piston (10) of the outer chamber (3), on the outer shell surface of which the thread (12) extending over the entire length is arranged; and the terminal member is designed as a threaded ring (13).

2. The pushing device according to claim 1, characterized in that the thread (12) is formed by a plurality of thread strips (21) arranged in the longitudinal direction.

3. The pushing device according to claim 1, characterized in that the thread (12) is designed as a trapezoidal thread.

4. The pushing device according to claim 1, characterised in that the threaded ring (13) has at least two threads and is fixed in the outer chamber (5) of the cartridge by clamping, gluing or the like.

5. Pushing device according to claim 1, wherein the pushing ram (11) has a wing-like rotary handle (19) at its rear end.

6. Pushing device according to claim 1 or 5, wherein the pushing ram (1) has a hexagon socket (20) for receiving a tool.

7. The pushing device according to claim 1, characterized in that the pushing rod (11) is integrally produced from plastic by injection molding.