RECESS ACTION GEARS, ALSO KNOWN AS LONG AND SHORT ADDENDUM GEARING, INCREASES THE ADDENDUM ON THE DRIVER AND REDUCES IT ON THE FOLLOWER TO OBTAIN AS MUCH RECESS ACTION AS POSSIBLE. THIS INCREASES THE EFFICIENCY AND WEAR LIFE OF THE GEARS. SEE SECTION TWO, P. 52.

LIMITATIONS:

1. ONE GEAR MUST ALWAYS BE THE DRIVER, AND THE OTHER A FOLLOWER. IN OTHER WORDS, IF THE CONTACT IS ALWAYS ON THE SAME SIDE OF THE GEAR TOOTH, REGARDLESS OF THE DIRECTION OF ROTATION, THEN STANDARD DESIGN, WITH THE PITCHLINE IN THE CENTER OF THE TOOTH DEPTH SHOULD BE USED. EXAMPLE-ELEVATORS AND HOISTS.

2. THE TABLE LISTS THE MINIMUM NUMBER OF TEETH TO AVOID POINTING OF THE GEAR TEETH, OR EXCESSIVE UNDERCUT, FOR A FULL DEPTH TOOTH AND A.157 FILLET RADIUS FOR 1DP. THESE SHOULD BE USED AS A GUIIDE ONLY; FOR ANY SMALL PINION, THE RADIUS TO UNDERCUT AND TO A POINTED TOOTH SHOULD BE CALCULATED.

THE FOLLOWING BASIC RACK, TERMS, SYMBOLS AND EQUATIONS APPLY TO ANY PRESSURE ANGLE AND TOOTH FORM. FOR FULL DEPTH TEETH, G-SHOULD BETWEEN O AND +1.0 FOR THE DRIVER, AND 0 TO -1 FOR THE FOLLOWER. IF G ₁ + G ₂= 0, THE GEARS WILL OPERATE ON A STANDARD CENTER DISTANCE, AND THE GENERATED AND OPERATING PRESSURE ANGLE WILL BE EQUAL.