Brown movement 155 converts a reciprocating input into intermittent wheel rotation. An elbow lever carries a pawl that advances the toothed wheel during the working stroke. Calculate the angle per stroke, total turns and average speed for a chosen number of teeth advanced.
From input stroke to feed increment
The elbow lever changes the direction of the reciprocating input and carries the pawl toward the wheel. Each working stroke advances a chosen number of teeth, followed by a return stroke. Tooth count and teeth advanced determine the angular feed increment used in the calculator.
Brown 155 Tooth-Index Explorer
Choose tooth count, declared teeth advanced per working stroke, complete strokes and stroke cadence. The worksheet reports exact ideal angular indexing and timing.
Equation Used
- The toothed wheel has z uniformly spaced teeth.
- The pawl advances exactly k whole teeth on each complete working stroke.
- The return stroke produces no reverse wheel motion in the ideal indexing calculation.
- The elbow lever and attached pawl are shown as constant-length rigid members in the schematic.
- Dimensions, tooth profile, holding detent, force, backlash, impact, wear, speed limit and safety are excluded.
The calculation uses the chosen teeth per stroke and completed-stroke count. The animation illustrates one working-and-return cycle with slowed playback; it does not simulate tooth contact forces or accumulated wear.
Brown movement 155
Henry T. Brown describes reciprocating rectilinear motion converted into intermittent circular motion by a pawl attached to an elbow lever and operating in a toothed wheel.
The source states that wheel direction depends on the side on which the pawl works. The animation shows one declared side and separates the working stroke from the return stroke.
Feed motion for planing machines and tools
Brown explicitly identifies movement 155 as a feed motion for planing machines and other tools. The plate is a compact topology, not a dimensioned industrial feeder design.
The feed increment follows the number of wheel teeth advanced on each working stroke. Applying the mechanism to a machine requires dimensions and contact geometry appropriate to that machine.
Declared whole-tooth indexing
A z-tooth wheel has angular pitch 360/z degrees. Declaring k whole teeth per working stroke gives 360k/z degrees per stroke and kN/z revolutions after N complete strokes.
Declared indexing example
For a 20-tooth wheel advancing one tooth on each of 20 complete strokes, the ideal index is 18 degrees per stroke and the wheel completes one revolution. At 30 strokes per minute, elapsed time is 40 seconds and ideal average wheel speed is 1.5 rpm.
What the Brown plate does not establish
Brown supplies the conversion principle, selectable direction and planing-machine feed context, but no dimensions, tooth count, number of teeth per stroke, tolerance, toggle force, spring preload, speed limit or wear criterion.
The calculation treats advance as an integer number of tooth pitches. It does not estimate positioning error from backlash, clearance, missed engagement or wear.
Brown 155 questions
What motion goes in?
Reciprocating rectilinear motion.
What motion comes out?
Intermittent circular motion of the toothed wheel.
Can the direction be reversed?
Brown states that direction depends on which side of the wheel the pawl works.
Does Brown specify one tooth per stroke?
No; teeth per stroke is therefore a declared input.
Brown movement 155 reference
- Henry T. Brown, Five Hundred and Seven Mechanical Movements, movement 155, plate 42 and text page 43: elbow-lever pawl conversion, selectable wheel direction and planing-machine feed use.
- 507movements.com edition notes: identifies the online edition as Brown's classic reference and explains that original illustrations and text are reproduced.
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