Paddle shaft assembly with adjustable-pitch paddles

Claim 1

An adjustable-paddle shaft assembly for a magnetic stirring apparatus comprising: a) an upper support shaft having a flared upper end and a first portion of a selected diameter, a beveled transition region joining the first portion to a second portion of reduced diameter, the second portion of the upper support shaft having a hole extending perpendicularly therethrough at a predetermined distance from the beveled transition region for accommodating a locking pin; b) a lower support shaft having two ends, one end having an axially oriented bore sized to receive the second portion of the upper support shaft, a hole extending perpendicularly through the lower support shaft for accommodating the locking pin upon the hole in the lower support shaft being aligned with the hole in the second portion of the upper support shaft, the remaining end of the lower support shaft having a perpendicular bore dimensioned and configured for receiving a portion of a removable stirring magnet; and c) at least one paddle member having a hollow body with an exterior surface, the hollow body being sized and configured to be removably press fitted over at portion of a removable magnet, the paddle member having at least one paddle attached to, and extending outwardly from, the exterior surface of the hollow body of the paddle member thereby allowing the paddle to be positioned at a preselected pitch with respect to the lower support shaft by positioning the paddle member about the magnet at the preselected pitch.