Water bath shaker
BACKGROUND OF THE INVENTION 
     The present invention relates to a water bath shaker apparatus and, more particularly, to a water bath shaker apparatus which includes a drive means for generating a shaking motion with a tub for accommodating the water of the water bath and with a shelf means disposed in the bath containing means for securing the container accommodating the liquid to be shaken, with the container being, for example, an Erlenmeyer flask. 
     Water bath shaker apparatus have been proposed which are of a considerable number of different designs. For example, in one proposed arrangement, a completely encapsulated drive mechanism is disposed in the water; however, a disadvantage of this proposed arrangement resides in the fact that corrosion occurs at the bearing sites. Moreover, the encapsulation of the drive mechanism renders the manufacturing of this proposed water bath shaker apparatus expensive, although the tube of the water bath can be covered entirely and securely by a lid for there is no significant heat loss which would normally occur with an open tub. 
     It has also been proposed to provide a water bath shaker apparatus wherein the shelf is driven from the outside by the drive means extending into the tube of the shaker apparatus. A disadvantage to this proposal resides in the fact that, although it is not as detailed as the aforementioned proposed water bath shaker apparatus, the shelf is not satisfactorily balanced and the tub of the water bath shaker apparatus can not be completely or easily covered. 
     The aim underlying the present invention essentially resides in providing a water bath shaker apparatus with a drive mechanism that is not only is simple in construction but is also considerably more balanced in such a manner that the tub of the water bath of the shaker apparatus can be completely covered. 
     In accordance with advantageous features of the present invention, a water bath of the aforementioned type is proposed which, in a surprisingly simple manner, includes a tub configured in the manner of a tube pan and, preferably, rotationally symmetrical, with the drive mechanism engaging in a central zone at a likewise rotationally symmetrical shelf. Consequently, the entire tub can be completely sealed by a lid in a maximally simple manner. Moreover, since the drive mechanism is not disposed in the water, not only are complicated gaskets or sealing means avoided but there is no possible corrosion at either the drive mechanism or associated bearing sites or locations. 
     Advantageously, in accordance with the present invention, the shelf is affixed to the drive shaft by a closed upside-down hollow cylinder means. Moreover, the shelf and hollow cylinder means are of a rotationally symmetrical structure. 
     The drive means of the present invention is adapted to produce a rotating shaking motion of the shelf, with the drive shaft executing an eccentric circular motion about an axis of symmetry of the tub in parallel to a longitudinally center axis of the drive shaft. 
     Furthermore, in accordance with the present invention, the drive shaft, during an eccentric circular rotation in one direction of rotation, revolves simultaneously about its own axis in another direction of rotation, with, as far as the amount is concerned, a respective number of revolutions being identical. 
     The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawing which shows, for the purpose of illustration only, one embodiment in accordance with the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The Single Figure of the drawing is a longitudinal cross sectional view of a water bath shaker apparatus constructed in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     Referring now to the Single Figure of the drawing, according to this figure, a water bath shaker apparatus generally designated by the reference numeral 5 comprises a housing 6 as well as a drive mechanism generally designated by the reference numeral 7 disposed in a bottom zone or area of the housing 6. The housing 6 includes a rotationally symmetrical tub 8, with a filling zone generally designated by the reference numeral 9 for the water 10, in the form of a closed ring with a central passage 11. A drive shaft 12 extends through the central passage 11 and, at the upper end of the drive shaft 12, a closed, upside-down hollow cylinder 13 is affixed thereto by an end face 14. A shelf 15 having in total, the structure or form of a circular ring adjoins the free end of the hollow cylinder 13. A securing means (not shown) secures a container such as, for example, an Erlenmeyer flask 16 on the shelf 15, with the flask 16 being adapted to be subjected to a rotating shaking motion executed by the shelf 15. 
     For this purpose, the drive shaft 12 executes an eccentric circular rotation about an axis of symmetry 18 of the tub 8 in parallel to a central longitudinal axis 17 of the drive shaft 12. At the same time, the drive shaft 12, during its eccentric circular motion in one direction of rotation revolves about its own axis 17 in the other direction of rotation, and with respect to the amount of rotation, a respectively identical number of revolutions are effected whereby the rotating shaking motion of the shelf 15 is produced. A lid 19 is provided for entirely covering the tub 8. 
     While I have shown and described only one embodiment in accordance with the present invention, it is understood that the same is not limited thereto but is susceptible to numerous modifications and changes known to one of ordinary skill in the art and I do not wish to be limited to the details described herein but only to the scope of the appended claims.