Press having a dosing system

Abstract

A press has a press ram actuated by a drive apparatus and a dosing system to be actuated by the drive apparatus for lubricating at least the drive apparatus.

Description

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

In the FIGURE, 10 designates in general fashion, as an example of a device according to the present invention, an electric press that is shown therein in schematic and partial fashion in longitudinal section. Electric press 10 comprises a press ram 11 that is guided in a tubular element 12 of the housing (not shown further) of the electric press. This press ram 11 performs a working stroke, indicated at 13, in which it shapes parts or fits them together.

Press ram 11 is actuated via a drive apparatus that comprises an electric motor indicated at 14 and a spindle drive 15. Electric motor 14 drives a threaded spindle 16, which is mounted in axially immovable fashion but is rotatable, on which sits a spindle nut 17 that is longitudinally displaceably but radially nonrotatable. By rotation of threaded spindle 16 about its rotation axis 18, spindle nut 17 is displaced along rotation axis 18, causing press ram 11, threaded onto the spindle nut at 19, to execute stroke 13.

A dosing system indicated at 20, comprising a lubricant cylinder 21 for the reception of lubricant, is provided for lubrication in particular of the thread region between threaded spindle 16 and spindle nut 17. Lubricant cylinder 21 comprises a tubular cylinder element 22, centeredly surrounding threaded spindle 16, adjoining which at the top is a flange 23. Cylinder element 22, flange 23, and tubular element 12 thus delimit an interior space 24 in which the lubricant is located.

A greasing piston 25, which is prevented from falling out by a stop 26, projects into this interior space 24. Greasing piston 25 is also arranged concentrically with threaded spindle 16 and is guided internally on tubular element 12.

Remotely from lubricant cylinder 21, greasing piston 25 has a stepped orifice 27 into which spindle nut 17 projects in such a way that a wall 28 of greasing piston 25 lies between spindle nut 17 and tubular element 12.

This wall 28 of greasing piston 25 is penetrated by a lubricant conduit 31, running parallel to rotation axis 18, that proceeds out from interior space 24 and ends in the region of an O-ring 32 at the point where greasing piston 25 is in contact with press ram 11 when electric press 10 is in the position shown in the FIGURE.

Provided in press plunger 11 is an angled lubricating orifice 33 that connects lubricant conduit 31 to a lubrication orifice 34 that passes radially through spindle nut 17 in the region of threaded join 19 and opens out in the region of the threads between threaded spindle 16 and spindle nut 17.

Of course it is also possible to configure greasing piston 25 without angled orifice 27 and wall 28, so that lubricant conduit 31 then ends directly at the end face of spindle nut 18, facing toward greasing piston 25, in which an angled lubrication orifice is then provided. In other words, it is not necessary for lubricant conduit 31 to be connected, via lubrication orifice 33 in press ram 11, to lubrication orifice 34 in spindle nut 17. It is thus possible to dispense with lubrication orifice 33 or to provide it directly in spindle nut 17. It is necessary for this purpose, however, to provide for greater manipulations on spindle nut 17, which is generally undesirable and is eliminated by the aforesaid configuration of greasing piston 25 and by lubrication orifice 33 in press plunger 11. In addition, greasing piston 25 is thus securely guided on spindle nut 17 and cannot tilt.

Provided below spindle nut 17 and between the latter, press ram 11, and threaded spindle 16, is a space 36 that opens toward threaded spindle 16. This space 36 is connected via a discharge orifice 37 to a pocket 38 that is provided on press ram 11 on its outer side 39, by which it is guided in tubular element 12.

Pocket 38 is in turn connected, by way of an orifice 41 provided in tubular element 12, to a reservoir 42 for used lubricant. This reservoir 42 is configured as a removable cassette 43 that is set in place from outside into a corresponding recess 44 in tubular element 12, and can be replaced without tools.

When electric press 10 as described so far is in operation, spindle nut 17 is located at a distance from greasing piston 25, so that greasing piston 25 is not moved during a working stroke 13. If a lubricating operation is now to be initiated, spindle nut 17 is then moved, by a corresponding rotation of threaded spindle 16, into the position shown in the FIGURE, where either spindle nut 17 or press ram 11 is in contact with greasing piston 25.

By way of a further stroke of spindle nut 17, upward (in the FIGURE) toward electric motor 14, greasing piston 25 is now moved farther into interior space 24, causing lubricant to pass through lubricant conduit 31 and lubrication orifices 33, 34 into the thread region between threaded spindle 16 and spindle nut 17. This lubricant displaces lubricant that has collected in space 36, and pushes it through discharge orifice 37 into pocket 38. When further lubricant is added, pocket 38 is emptied via orifice 41 into reservoir 42, which can be cleaned by removing cassette 43.

Space 36 now contains fresh lubricant, so that as operation of electric press 10 continues, continuous lubrication between threaded spindle 16 and spindle nut 17 is ensured by, so to speak, a co-moving lubricant reservoir. The used lubricant once again collects in space 36 and is replaced, in the manner described, by new lubricant after a predefined number of working strokes.

At each lubricating operation, greasing piston 25 moves somewhat farther into interior space 24, so that at each lubricating operation, pocket 38 is located somewhat higher up. In the position shown in the Figure, the pocket is still located with its upper end 45 in the region of orifice 41, since it was assumed in this case that interior space 24 is completely filled with lubricant. During the service life of electric press 10, pocket 38 now continues to migrate farther up as lubricating operations occur, until ultimately it is located with its lower end 46 in the region of orifice 41. Pocket 38 has an extension in the direction of rotation axis 18 that corresponds to the maximum stroke of greasing piston 25 in lubricant cylinder 21.

During a working stroke 13 of electric press 10, pocket 38 is moreover sealed by way of the inner wall of tubular element 12, so that used lubricant located there cannot escape in any other way. Since the lubricant is generally grease, lubricant present in reservoir 42 also cannot easily pass back through orifice 41 into the interior of electric press 10.

Also shown to the left next to electric motor 14 is a lubrication nipple 47 through which interior space 24 of dosing system 20 can be filled with lubricant. Once electric press 10 has been completely assembled, lubricant is pressed through this lubrication nipple 47 into interior space 24 until it has propagated through lubricant conduit 31, lubricant orifices 33, 34, and discharge orifice 37 into pocket 38, and from there through orifice 41 into reservoir 42. In other words, lubricant is introduced at lubrication nipple 47 until it emerges again from orifice 41.

In the same manner, it is also possible to replace all of the lubricant after electric press 10 has been in operation for a long time. This is done by introducing fresh lubricant once again through lubrication nipple 47 until all the used lubricant has collected in reservoir 42.

Not only electric press 10 but also dosing system 20 are controlled via a control system indicated at 48, which comprises, inter alia, a position and force measurement system indicated at 49. By way of control system 48 and position and force measurement system 49, spindle nut 17 and thus press ram 11 can be moved in defined fashion, their precise axial position being reported to control system 48 at all times via position and force measurement system 49.

Control system 48 now makes it possible for the actuation of dosing system 20 also to be accomplished on the basis of concrete operating states of electric press 10. For this purpose, control system 48 senses the loads--i.e. number of working strokes, respective stroke length, stroke speed, and force exerted--then integrates these operating states and initiates a lubrication action based on specifications of the manufacturer of the spindle drive. Dosing system 20 can thereby be actuated precisely and on the basis of need.

For this purpose, control system 48 stores the axial position of spindle nut 17 at the end of a dosing operation, and then returns to precisely that position when a new lubrication action is necessary. In addition, the quantity of lubricant delivered can be exactly metered by way of electric motor 14.

In conclusion, be it also noted that dosing system 20 does not require a separate actuation apparatus, but rather the lubricating operation is also effected by way of control system 48, which already activates electric motor 14 to perform the working stroke. All that must additionally be provided, compared with an electric press 10 without a dosing system 20, are lubricant cylinder 21 and greasing piston 25; in addition, lubrication orifices 33 and 34 must be installed, and space 36 must be provided for, for example by way of an appropriate washer when press ram 11 and spindle nut 17 are threaded together. Discharge orifice 37, pocket 38, orifice 41, and reservoir 42 can be dispensed with if it is acceptable for used lubricant to be distributed and to collect in undefined fashion in electric press 10.

Claims

1. A device having a part actuated via a drive apparatus, wherein

a dosing system to be actuated by the drive apparatus is provided for lubricating at least the drive apparatus;

the drive apparatus comprises a spindle drive and an electric motor for actuating the spindle drive;

the spindle drive comprises a threaded spindle, driven by the electric motor and mounted in axially nondisplaceable fashion, and a spindle nut that is axially displaceable via the threaded spindle but is radially nonrotatable, and is joined to the actuated part; the dosing system comprising a lubricant cylinder to be filled with lubricant and a greasing piston for ejecting the lubricant and projecting into said cylinder's interior, the greasing piston being actuated via the drive apparatus.

2. The device as in claim 1, wherein the part is a handling device having an actuated positioning part.

3. The device as in claim 1, wherein the part is a press having a press ram actuated by the drive apparatus.

4. The device as in claim 1, wherein the greasing piston is in working engagement with the spindle drive as a function of the axial position of the actuated part.

5. The device as in claim 1, wherein the greasing piston comes into contact with the spindle nut when the actuated part is in an axial position outside its working stroke.

6. The device as in claim 1, wherein the lubricant cylinder is provided preferably concentrically with the threaded spindle, preferably on the side of the spindle nut remote from the press plunger, and the greasing piston is arranged preferably concentrically with the threaded spindle between the lubricant cylinder and the spindle nut.

7. The device as in claim 6, wherein there is provided in the greasing piston a lubricant conduit that connects the interior space of the lubricant cylinder to a lubrication orifice in the spindle nut and opens out in the region of the threaded spindle, when the spindle nut is directly or indirectly in contact with the greasing piston.

8. The device as in claim 7, wherein there is provided in the press ram a discharge orifice for used lubricant that opens below the spindle nut into a space between the spindle nut, threaded spindle, and press ram, and connects that space to a reservoir for used lubricant.

9. The device as in claim 8, wherein the discharge orifice opens into a pocket that is provided on the press ram on its outer side that is guided in a tubular element, an orifice being provided in the tubular element and connecting the pocket to the reservoir.

10. The device as in claim 9, wherein the pocket has, in the axial direction of the threaded spindle, an extension that corresponds approximately to the maximum stroke of the greasing piston in the lubricant cylinder.

11. The device as in claim 8, wherein the reservoir is a replaceable cassette that is mounted on the device in externally accessible fashion.

12. The device as in claim 7, wherein an O-ring is provided between the lubricant conduit and the lubrication orifice, ensuring a seal between the lubricant conduit and the lubrication orifice during lubrication.