Dispensing cartridge

Abstract

The present invention relates to a dispensing cartridge, particularly for dental impression materials, formed from a plastic material having at least one inlet and at least one outlet, and comprising a metal reinforcement tube.

Description

FIELD OF THE INVENTION [0001] This application claims priority from EP Application No. 03013831.7, filed Jun. 18, 2003. [0002] The present invention relates to a dispensing cartridge, particularly for dental impression materials, of the type adapted to be releasably received in an applicator having a moveable plunger. BACKGROUND OF THE INVENTION [0003] A number of dispensing devices are available for dispensing various types of materials. In many instances, the dispensing device is an assembly that includes a reusable dispenser or applicator and a disposable cartridge. The cartridge contains a quantity of a composition or material to be dispensed and is releasably received in a receptacle of the applicator. [0004] In one type of dispensing devices, that include an applicator and a cartridge, the applicator has a plunger that is advanced by the user during a dispensing operation. Often, the plunger is received in an open end of the cartridge and bears against a piston within the cart...

AI Technical Summary

Benefits of technology

[0009] In view of the above, the present invention provides a dispensing cartridge, particularly for dental impression materials, with improved stability.

[0014] It is preferred that the metal tube extends beyond the compartment. In this case, the cap of the foil bag is received at the outlet opening of the metal tube. This prevents a radial pressure load onto the caps due to the pressurized bag, and thus prevents breaking of the caps.

[0018] It is preferred that the open end of the metal reinforcement tube comprises a flared flange or a chamfer. It is also preferred that the open end of the compartment comprises a chamfer or truncated cone. The flared flange or chamfer at the open end of the tube and the chamfer or truncated cone at the open end of the compartment are designed and dimensioned such that there is a smooth transition provided between these two areas in the interior of the cartridge. Preferably, the outmost edge of the flared flange is embedded in the compartment body wall. Thus, the inner diameter of the cartridge, starting from the outmost edge of the compartment / cartridge, decreases as the outlet opening is approached. This facilitates insertion of the plunger during assembly of the cartridge.

[0022] The invention in its various aspects as described is a significant advantage as the metal tubes prevent the cartridge from breaking when overstressed by application forces (e.g., 2000-4000 N) or misuse or by any sort of inadvertent impact. According to a preferred embodiment, the metal reinforcement tubes especially reinforce the rim of the cartridge which is the interface to the caps of the foil bags. Furthermore, the use of a, e.g., stainless metal tube gives an excellent size stability and allows to use plastic materials for the compartment body with better chemical and mechanical characteristics. Moreover, the plastic body can be designed a lot easier in terms of material accumulations.

Problems solved by technology

Moreover, the plastic material has to be easy to handle in the injection mould, i.e., low shrinking rate and little ability to form shrink marks.

These different requirements are difficult to meet.

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