Machine element or mechanism – Gearing – Directly cooperating gears
Reexamination Certificate
1998-12-29
2001-11-20
Bucci, David A. (Department: 3682)
Machine element or mechanism
Gearing
Directly cooperating gears
Reexamination Certificate
active
06318203
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a drive for a rotating article
Such a drive has already been disclosed by European Laid-open Specification EP 083 8610 A2. The main item of this drive is at least one pivotably mounted lever, which interacts with a gear, which is connected to the rotating article in a rotationally fixed manner. To this end, there is a device for mounting and guiding the lever for a driving forward motion, meshing with the gear, of the lever.
This drive has the advantage that it is essentially insensitive to contaminants which occur due to a liquid in which rollers, shafts or the like rotate in an air-humidifying and cleaning unit, a deodorizer or the like. For even if the gear is wetted in the process by the liquid due to the rotational motion in the liquid, the only point of contact with the further components of the mechanism is in that part of the lever which meshes with the gear. However, this part of the lever is simple to clean as a rule.
However, a disadvantage of this mechanism consists in the fact that, in particular due to the occurrence of production tolerances of the drive parts, smooth, quiet running of the rotating article is impaired from time to time, since, in particular, the meshing lever may become stuck with the gear.
SUMMARY OF THE INVENTION
The object of the invention is to provide a drive which has improved synchronism and is in particular less sensitive to production tolerances.
The invention is based on a drive for a rotating article for a roller, shaft, plate or the like, in particular for a deodorizer, an air humidifier or an air-cleaning unit or the like, which has the following features.
A movably mounted lever, a gear which is connected to the rotating article in a rotationally fixed manner, and a lever mechanism means for a driving motion, meshing with the gear, of the lever in order to rotate the gear, are provided with the lever having a tip for meshing with the teeth of the gear. The central idea of the invention, then, is to design the tip in the form of a tooth, the shape of this tooth and that of the teeth of the gear as well as the lever mechanism being matched to one another in such a way that the tooth flanks of the tooth on the at least one lever and the respectively meshing tooth on the gear roll on one another during the driving motion. This measure achieves a situation in which the drive, even when production tolerances occur, sets the gear and the rotating article in a smooth motion, in the course of which sticking of lever tip and gear can be avoided. This is because the configuration according to the invention essentially fulfills the mathematical interrelationships of a conventional tooth system between two gears. In addition, the wear of the tooth flanks in contact is thereby markedly improved compared with the solution from the prior art, since the sliding motion, which is otherwise present, between the flanks is greatly reduced and is essentially replaced by a rolling motion. This has a positive effect, in particular, on the service life of the drive and on the operating noise.
In order to improve the synchronism of the drive still further, it is also proposed that the shape of the tooth on the lever and that of the teeth of the gear as well as the lever mechanism be matched to one another in such a way that the tooth flanks of the tooth on the at least one lever and the respectively meshing tooth on the gear, during the driving motion, have a point of contact at which the flanks roll on one another without radial sliding (rolling point).
The shape of the tooth on the lever and that of the teeth on the gear are preferably designed according to the rules of tooth engagement as an involute, cycloidal or circular arc tooth system or as a lantern tooth system, in which the tooth on the lever has, for example, the shape of a pin. In this way, an essentially constant transmission ratio between lever mechanism and gear can be realized.
In an especially advantageous refinement of the invention, the lever mechanism contains guide surfaces for the lever for the sliding guidance of the lever. As a result, the lever, in a guided manner, can perform, for example, a forward motion, a reverse motion and a pivoting motion. In this connection, it is advantageous if the lever mechanism comprises an eccentric drive for the lever. By the articulation points of the lever and the guide surfaces on the housing of the lever mechanism being geometrically arranged in such a way as to be appropriately matched to one another, a desired coupler curve can be realized for the cyclic meshing of the tooth-shaped tip of the at least one lever. Instead of the operating principle, thereby realized, of the slider-crank mechanism, the operating principle of the inverted slider crank, in which the longitudinal guide is located in the lever, and, for example, a pin secured in the housing of the lever mechanism engages in this longitudinal guide, may also be applied in another embodiment.
Furthermore, to realize a simple eccentric drive, it is proposed that this eccentric drive have a drive shaft for the lever, and this drive shaft is arranged eccentrically on a gear. The gear may be driven continuously, preferably by means of a worm. As a result, extreme transmission ratios are possible on the one hand, which is necessary in particular during use in a deodorizer or air washer according to the invention, where only one motor is used for the direct drive of the fan and the drive of one or two plate stacks. On the other hand, a worm gear unit constitutes a so-called self-locking gear unit, as a result of which the at least one lever is locked against undesirable motion.
In a preferred embodiment, the drive shaft is attached directly and eccentrically to a gear which is driven by a worm.
The worm is preferably connected to the drive shaft of a motor via an elastic coupling. In this way, the drive shaft need not be absolutely exactly in alignment with the worm shaft. In this case, larger tolerances during the production of a drive according to the invention are possible, which, inter alia, brings about a cost saving.
In an especially advantageous refinement of the invention, there are two, three or more levers, which mesh alternately with the gear. As a result, at least one lever is constantly in mesh with the toothed or pin ring of the rotating article, so that the latter is driven smoothly. Furthermore, in the event of the levers being locked by a worm gear unit against an undesirable motion, it is ensured that the rotating article is also secured against any undesirable further motion, for example against turning back, by at least one meshing lever. The rotation of the rotating article is therefore constantly controlled in a mechanically fixed manner by the lever drive.
Furthermore, it is especially preferred if the at least one lever is elastically mounted between the guide surfaces of the lever mechanism. As a result, the lever is prestressed in the lever mechanism and exhibits no play even where there are production tolerances. Excessive play could, in the worst case, lead to the tooth of a meshing lever colliding with a tooth of the gear or to the teeth sticking.
In this case, it is especially preferred if, to elastically mount the lever between the guide surfaces, at least part of the outer contour of the lever gripped by the guide surfaces is elastically resilient. In this connection, it is advantageous if, to realize an elastically resilient outer contour of the lever, the outer contour is designed as a narrow frame. In particular, if the lever is made of plastic, this contour region consequently has elastic properties.
Furthermore, in order to further improve the elastic properties, it is preferred if the frame is interrupted, a spring element being fitted in place at the point of interruption.
Finally, in order to ensure effective force transmission of the at least one lever to the gear, it is proposed that that region of the outer edge of the lever which is supported on a guide surface of the lever mechanism in order to a
Harter Erich
Hitzler Alfred
Bucci David A.
Hansen Colby
Kinberg Robert
Spencer George H.
Venable
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