System for the controlled dispensing of a lubricant

Abstract

A device for the controlled dispensing of a lubricant from a cylindrical cartridge (1), comprising a dispensing piston (2) which exerts pressure on the lubricant to dispense it, wherein the dispensing piston (2) is provided with a through-opening (3) which is connected to a piston tube (4) through which the lubricant is directed to an outlet opening (5) of the device, wherein the through-opening (3) is designed as a central bore of the dispensing piston (2) in which a check valve (6) is installed, characterized in that the dispensing piston (2) is essentially shaped on its underside as a flat cone with its tip pointing downwards, which plunges into the cartridge (1), and that the tip of the cone is formed by the ball (6') of a check valve (6) installed in the central bore of the dispensing piston (2).

Description

[0001] The invention relates to a system for the controlled dispensing of a lubricant from a cylindrical cartridge, with a dispensing piston which exerts pressure on the lubricant to dispense the lubricant, wherein the dispensing piston is provided with a through-hole which is connected to a piston tube through which the lubricant is directed to an outlet opening of the system, wherein the through-hole is designed as a central bore of the dispensing piston.

[0002] Lubricants are increasingly being offered in handy, standardized Eurocartridges, in addition to the usual container sizes. The use of these 400 ml cartridges as lubricant reservoirs is particularly advantageous where only small amounts of lubricant are required and easy handling is essential. This avoids exceeding maximum processing times when using larger containers, as well as time-consuming container changes.

[0003] Hand-operated devices are currently predominantly used to dispense the lubricant from these cartridges. These devices, also known as grease guns, are labor-intensive to operate depending on the viscosity of the lubricant used, and the amount of lubricant dispensed is very difficult to control.

[0004] Motorized grease guns are also known, which at least simplify handling compared to the previously mentioned hand-held devices.

[0005] For example, utility model DE 20 2008 006 952 U1 discloses a system in which a spring-loaded dispensing piston plunges into the cartridge to apply the lubricant and exerts pressure on the lubricant. The lubricant exits the cartridge from the side opposite the dispensing piston and enters a T-shaped channel connected to a hydraulic pump. During operation, the hydraulic pump also exerts pressure on the lubricant and propels it towards the outlet opening. A check valve prevents the lubricant from flowing back from the T-shaped channel into the cartridge.

[0006] EP 0 806 602 A1 discloses a system according to the preamble of patent claim 1. In this system, pressure is exerted on the lubricant by means of a dispensing piston. The dispensing piston is provided with a through-opening connected to a piston tube through which the lubricant is directed to an outlet opening of the system. The through-opening is designed as a central bore in the dispensing piston. The lubricant cartridge is axially compressed during the dispensing process, which is why, due to its design, the dispensing piston is not immersed in the lubricant cartridge.

[0007] A similar system is also shown in EP 1 213 529 A1. In this system, a specific amount of lubricant is pumped to an outlet in a two-stage process: first, it is pumped from a reservoir into a passageway and then, in a second step, from this passageway to the outside. For this purpose, check valves are installed on the inlet and outlet sides of the passageway.

[0008] DE 103 47 176 A1 discloses a grease handling system with a plurality of portable grease storage containers. The grease storage containers each have a grease chamber and a compressed air chamber separated by a movable wall. Pressurizing the grease chamber with compressed air exerts pressure, thereby transporting the grease through a pipe to an outlet valve.

[0009] WO 97 / 26456 A1 shows a feed pump for liquid or viscous media with a motor drive device.

[0010] The present invention represents a system specially developed for the automatic and process-reliable emptying of, in particular, standardized lubricant cartridges, which is equally suitable for use at manual workstations as well as in automated assembly systems for lubricant supply.

[0011] This is achieved according to the invention in that the dispensing piston is shaped on its underside essentially as a flat cone with its tip pointing downwards, which dips into the cartridge, and in that the tip of the cone is formed by the ball of a check valve mounted in the central bore of the dispensing piston.

[0012] This embodiment according to the invention makes it possible to leave the lubricant cartridge closed on the side facing away from the dispensing piston and to control the pressure exerted on the lubricant by controlling the force with which the lubricant cartridge and dispensing piston move towards each other.

[0013] In a preferred embodiment of the system according to the invention, the cartridge is placed in a guide tube made of stainless steel, which serves as a guide for the dispensing piston during automatic emptying and also ensures the dimensional stability of the cartridge.

[0014] In a preferred development of the system according to the invention, it is provided that, in order to improve the venting of the cartridge, the ejection piston is provided with an additional thin bore which is connected to a line for venting the cartridge.

[0015] Further advantageous embodiments and developments of the system according to the invention emerge from the subclaims and are explained with reference to the drawing.

[0016] Showing: Fig. 1: a system according to the invention in longitudinal section with a detailed enlargement of the extrusion piston Fig. 2: the system from Fig. 1 in a view rotated by 90°

[0017] The system according to the invention, shown in the drawing, for the controlled dispensing of a lubricant from a cylindrical lubricant cartridge 1 is designed as a floor-standing unit based on a standard column frame 10. The dimensions of the system are designed for the use of cartridges 1 with a 400 ml capacity, also known as Euro cartridges, which are commercially available as lubricant storage devices. For use in the system according to the invention, such a Euro cartridge is opened only on one side, which is usually closed only with a lid, and placed in a guide tube 7 made of stainless steel. This guide tube serves as a guide for an dispensing piston 2 during automatic emptying and also ensures the dimensional stability of the cartridge 1, which is usually made of plastic.Together with the guide tube 7, the cartridge 1 is placed in a holder with the open side facing upwards and locked at the top edge with a retaining clip 18 to prevent tipping during emptying.

[0018] Above the inserted cartridge 1 is a dispensing piston 2, the outer diameter of which is matched to the inner diameter of the cartridge 1, and which is provided with a through-hole 3 designed as a central bore. The dispensing piston 2 is connected at its top to a piston tube 4, which serves as the outlet line. A check valve 6 is installed in the through-hole 3 itself, which prevents lubricant from flowing back from the piston tube 4 into the cartridge 1. The piston tube 4 leads to an outlet opening 5 at the top of the system, which can be opened and closed by a manually operated valve 8. Also at the top of the system, the piston tube 4 is equipped with a pressure gauge 9, on which the pressure prevailing in the outlet line can be read.

[0019] The dispensing piston 2 is shaped on its underside essentially as a flat cone with its tip pointing downwards, with the tip of the cone being formed by the ball 6' of the check valve 6. Before reaching the outer diameter of the dispensing piston 2, the conical shape transitions into a cylindrical shape provided with a step. Below this step, the dispensing piston 2 is provided with an additional thin bore 11, which is connected to a line 12 for venting the cartridge 1. This vent line 12 is provided at the top of the system with a manually operable vent valve 13 for opening and closing the same.

[0020] The dispensing piston 2, the piston tube 4, and the vent line 12 are rigidly connected to the column frame 10. The cartridge 1, held by the guide tube 7, is positioned on a carriage 14 that can be moved vertically along the frame 10. The drive for this adjustment is provided by a pneumatic cylinder 15, which is mounted parallel to the holder for the cartridge 1. A plate 17 is attached to the upper end of the piston rod 16 of the pneumatic cylinder 15, which in turn is connected to the travel carriage 14 for the cartridge 1. By means of compressed air supplied from the outside, the piston rod 16 of the pneumatic cylinder 15, and thus the cartridge 1, can be moved up and down.

[0021] To dispense the lubricant, the cartridge 1, positioned on the slide 14 with the guide tube 7, is moved upwards. When the dispensing piston 2 is inserted into the cartridge 1, any air still contained therein can initially escape through the vent line 12. This is facilitated by the special shape of the dispensing piston 2, which causes the air to escape towards the wall of the cartridge 1 and thus towards the vent hole 11. As soon as lubricant is continuously being delivered from the vent line 12, it is closed with the vent valve 13. As the cartridge 1 is raised further, the lubricant is delivered through the passage opening 3 of the dispensing piston 2 and the piston tube 4 connected to it to the outlet opening 5, where the outlet of the lubricant is released or prevented by opening and closing the valve 8.If no lubricant is required for an extended period of time, switch 19, which is used to raise and lower the slide 14, can be moved to a central position, thus depressurizing the pneumatic cylinder 15. The slide 14 and, with it, the cartridge 1, then remain in the assumed position, but without the lubricant being pressurized, which helps protect the lubricant.

Claims

[1] System for the controlled dispensing of a lubricant from a cylindrical cartridge (1), with a dispensing piston (2) which exerts pressure on the lubricant to dispense the lubricant, wherein the dispensing piston (2) is provided with a passage opening (3) which is connected to a piston tube (4) through which the lubricant is guided to an outlet opening (5) of the system, wherein the passage opening (3) is designed as a central bore of the dispensing piston (2) in which a check valve (6) is mounted, characterized by that the dispensing piston (2) is shaped on its underside substantially as a flat cone with its tip pointing downwards, which dips into the cartridge (1), and that the tip of the cone is formed by the ball (6') of a check valve (6) mounted in the central bore of the dispensing piston (2). [2] Plant according to claim 1, characterized bythat the cartridge (1) is accommodated in a guide tube (7) which serves as a guide for the ejection piston (2) during emptying. [3] Plant according to claim 1 or 2, characterized by that the dispensing piston (2) is provided with an additional thin bore (11) which is connected to a line (12) for venting the cartridge (1). [4] Installation according to one of claims 1 to 3, characterized by that the cartridge (1) is positioned on a carriage (14) which can be moved in a vertical direction along a column frame (10). [5] Plant according to claim 4, characterized by that a pneumatic cylinder (15) is mounted parallel to the holder for the cartridge (1) as a drive for adjusting the slide (14).

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