Roymech

Reciprocating Mechanisms


Reciprocating Mechanisms

More details on Mechanism design are to be found in the links below the table

Reciprocating Mechanisms

Reciprocating straight line motion is most generally completed using pneumatic, hydraulic, and electric linear actuators.   Reciprocating motion is also achieved using rack and pinion, and cams.   Historically a number of machines have been operated very successfully using specially developed mechanisms.



Scotch Yoke Mechanism

The mechanism below achieves reciprocating motion of the yoke (d) as the arm (b)is rotated.  This mechanism delivers harmonic motion.

  


Scotch Yoke


Offset Slider Crank

The offset slider crank produces a (working stroke time/return stroke time) ratio greater than unity based on the rotation direction and degree of offset.   With no offset and a relatively long connecting link the ratio is unity.  There is an advantage with having a faster return stroke in that this motion does no useful work and takes up valuable time.


Offset Slider Crank


The Shaper Mechanism

Variations of this mechanism were universally used for providing the cutting motion of shaping machines.   Again this mechanism has the advantage of a quick return cycle.  This mechanism is a derivation of the offset slider mechanism..


Shaper Mechanism


Whitworth Quick Return Mechanism

This is another variation of the shaper mechanism providing slightly different motion characteristics and a different geometry.


Whitworth Quick Return Mechanism



Links to Reciprocating Mechanism Design
  1. Whitworth Mechanism An applet showing the quick return motion
  2. Mechanisms ..A site with lots of useful moving graphics for simple mechanisms
  3. Introduction to Mechanisms ..Lots of very useful reference notes
  4. Animated-Reciprocating mechanisms ..Clear Moving Pictures