A Simple Laboratory Shaking Machine JOHN H. HIGHBERGER, Department of Leather Research, University of Cincinnati, Cincinnati, Ohio
FIGURE1. LARGEMODEL
M "T
in 6.4- to 7.6-cm. (2.5- to 3-inch) widths. Such an elastic is slipped around the container, which is then set on the box next to one of the slots. The elastic is then pulled through the slot from the other side of the board, and stretched to permit the insertion of a second container on that side. The containers are thus securely held in pairs, one on each side of the board, and their attaching or removal is merely a matter of slipping the elastic on or off. For the larger sizes of containers the elastics should be cut from one of .the large-size inner tubes used in truck tires. These are easily obtainable a t most garages. For use with smaller sizes of containers the modification shown in Figure 2 was suggested by W. P. Doelger of this department. The same method of fastening the bottles on the machine is used, but as the weight is not so great in this case, no base is necessary for them to rest on, and they are supported only by the elastics passed through the slots as before. The apparatus consists essentially of a 2.54cm. (I-inch) oak board, 91.4 cm. (36 inches) long, which rotates about its long axis. Five 5.1 X 20.3 cm. (2 X 8 inch) slots make it possible t o accommodate 10 containers. The board is suspended between two shaft hangers by means of two 20.3-om. (8-inch) lengths of 2.54-cm. (1-inch) steel shaft, each of which is welded to a pipe flange bolted t o one of the end pieces of the board. The shaft hangers are of 20.3-cm. (8-inch) drop and are mounted by means of wooden blocks so that the shaft center is 24.1 cm. (9.5 inchea) above the table top. The machine is driven by a 0.125 h. p. motor operating through a speed reducer of 50 to 1 ratio.
of the laboratory shaking machines on the market
Oh' suffer from the faults of overcomplication and lack of
adaptability. Inasmuch as agitation is a frequent and important operation in this laboratory, both in analytical and experimental work, considerable thought was devoted to the design of a machine which would present the utmost in simplicity and versatility. It was particularly desired to keep as simple as possible the method of holding in place the containers to be agitated, and a t the same time permit the simultaneous use of different sizes of vessels on the machine, The principle adopted to these ends, and incorporated in the two machines shown in Figures 1 and 2, has been in satisfactory use in this laboratory for the past 3 years.
FIGURE2.
The larger of the two machines, shown in Figure 1, will accommodate 24 bottles of any size up t o about 2 liters. The body consists of a rectangular box 30.5 X 30.5 X 61 om. (12 X 12 X 24 inches), from each side of which projects a 30.5 X 61 cm. (12 X 24 inch) board, mounted on its long edge along the center line of the box. The boards, which are of 1.91-cm. (0.75-inch) stock, are fastened to the box with screws, and held rigidly in place by means of 1.91-cm. (0.75-inch) strap iron supports. Three slots, 5.1 X 17.8 om. (2 X 7 inches), are cut in the lower side of each board, next to the face of the box. The whole is mounted, by means of two short lengths of 3.014-cm. (1.187-inch) steel shaft secured to the ends of the box by means of metal face plates, between twO inverted pressed-steel shaft hangers, which serve as supports. Ring oiling bearings are used in the hangers, which are of 58.4-crn. (23-inch) drop, mounted on wooden blocks so that the shaft center is 67.3 cm. (26.5 inches) above the floor. The machine is rotated by a belt drive throu h a speed reducer of 50 to 1ratio, driven by a 0.25 h. p. motor. gpeeds of 30 t o 60 r. p. m. are satisfactory for most purposes, and may easily be altered to suit the particular work by means of multiple pulleys.
%ALL
MODEL
The relative cheapness of such a machine is realized from the fact that the cost of the smaller model was approximately fifty dollars. This includes the motor and speed reducer, and the cost of welding the pipe flanges to the shaft. The cost of the larger model is naturally somewhat higher, principally because of the use of larger shaft hangers and motor. A saving could probably be effected in the construction of these machines by the substitution of wooden supports for the pressed-steel shaft hangers, but the convenience and neat appearance of the latter, together with the ease with which the shaft may be properly aligned by means of their adjusting screws, makes their added expense well justified.
Acknowledgment The writer is indebted to E. K. Moore of this department for much help in the design and construction of these machines.
The esaential idea of the machine is the method of holding the containers in place. For this purpose use is made of large circular elastics cut from discarded rubber inner tubes. For most sizes of bottles or jars these are most satisfactorily cut
RIBCEIVED Maroh 12, 1930.
227
