A Versatile Support for Laboratory Stirring Motors K. D. Cowan. H. Hall. and E. J. ~isenbraun'
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Oklahoma State University, Stillwater, OK 74078 g Conventional laboratory stirrers are supplied with a round rod, fastened perpendicular to the axis of the stirring shaft, for attaching the stirring motor to a ring stand. Unless this rod is securely clamped to the ring stand, the torque of the stirring motor and vibration from stirring can cause a shift in the alignment of the stirring rod with the adapter used to seal the stirring shaft to a reaction flask. Some manufacturers provide a hexagonal rod that is an improvement. However, if stirring of viscous materials or very rapid stirring is involved, the potential for damage exists in the event that the stirring A- 1 motor shifts position during use. The stirring-motor support, shown as A-1, A-2, and B, was designed to overcome the above mentioned problem by providing a stable two-point attachment of a laboratory stirring motor such that lateral movement is prevented b during use. These components are put into use by first detaching the rod supplied with the stirring motor and attaching the motor-support plate A-1 in its place using the four set screws b. Openings for these set screws may be tapped into the motor housing. In some cases, the holes b used to fasten the original support rod will serve. Motorsupport plate A has a projection a a t each corner. These projections (6 mm square x 3 mm in height) serve to prevent movement when motor-support plate A, with stirring motor attached, is joined to support plate B. As shown in the side view A-2, projections a are an integral part of motor-support plate A and they were constructed by milling a Vls- x 4-in. square of aluminum to a depth of 3 mm. In use, screw d of motor-support plate A is inserted through slot h of support plate B and these parts are then securelyjoined by tightening retaining nut c. Plate B is 86 mm wide and was constructed to fit between the a projections of motorsupport plate A. Once assembled, the stirring motor may be attached to two ring stands or a lattice framework as shown in C. In this arrangement, the high speed stirring shaft k is used. If the more powerful but slower stirring shaft 1 is needed, nut c is loosened and the stirring motor is rotated 90' clockwise. This change requires repositioning of the stirring motor, and this usually can be accomC plished by sliding it along slot h. Slot e also may be used for position adjustLegend Common to all Components ment. Because motor-support plate A is Front view of motor-support plate and retaining nut c. symmetrical, it also is possible to fasten A-1 Side vlew of motor-support plate and retaming nut c. the horizontal rods g and j to a single A-2 ring stand and to use either of the stir- B Adjustable support-plate assembly (360 mm x 86 m m x 8 mm). ring shafts k and 1. This flexibility in PO- C Stirring motor assembled with components A-B. sitioning a stirring motor can be very a Projection (4 ea., 6 mm x 6 mm) to restrict movement of the stirring motor after useful in cramped working quarters. components are assembled. The shaft adapter m was built to in- b Set screws (4 ea.) to fasten motor-support plate A to motor. crease the size of the stirring motor shaft c Retaining nut to lock motor-support plate A to the adjustable support-plateassembly B. to match the diameter of glass stirring d Screw to connect plates A and B using retaining nut c. rods. Slotted hole for posit~onadjustment of set screw f and horizontal support rod g. e The stirrers currently in use in our f Set screw to hold adjustable support rod g. laboratories are a mixed lot acquired g Adjustablesupport rod (0.5in, 8 in,), a variety they h Slotted hole used for adjust~ngpos~t~on of motor-support plate A. now have the common feature of being Set screw to hold stationary support rod j. fitted with universal motor-support j Stationary support rod (0.5 in. x 10 in.). plate A that enables interchange of any High-speed stirringshaft, stirrer with plate B. I Low-speed stirring shaft. rn Shaft adapter to enlarge st~rr~ng shaft. 'corresponding author.
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Journal of Chemical Education
