BIZOMAT MAKEOS · Mechanics

Toggle Joint Force

What output force does this toggle joint produce for the applied force?

Output (resisting) force and mechanical advantage of an equal-arm toggle joint from the applied force and the link angle, for clamps, presses and crushers.

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How this tool works

Inputs, units and where to find them

InputUnitTypical source
Force applied at the joint (perpendicular to the output line)NForce applied to the central joint, at right angles to the line along which the output moves.
Angle of each link from the output line°Angle between each link and the output line; it falls towards zero as the links straighten.

What each input means

Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.

What this means: Force applied at the joint (perpendicular to th…
Illustration: Force applied at the joint (perpendicular to the output line)A block with an arrow pushing on it; the arrow is the force Force applied at the joint (perpendicular to the output line).PExample: 500 NForce applied at the joint (perpendicular to…
What it is
The force pushing on the central pin of the toggle, acting at right angles to the line along which the output moves.
Units and format
Enter a number in N: newtons. The form accepts 0.000001 N or more. Required: the tool does not calculate until every input is valid.
Example
The form opens with 500 N as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Effect on the result
Output force and link forces rise in direct proportion.
Get it right
It must act at right angles to the output line; an angled force needs resolving first.
What this means: Angle of each link from the output line
Illustration: Angle of each link from the output lineTwo lines meeting at a point with an arc between them, marking the angle Angle of each link from the output line.αExample: 10°Angle of each link from the output line
What it is
The angle between each link and the output line. It gets smaller as the links straighten towards a straight line.
Units and format
Enter a number in °: degrees of angle. The form accepts 0.1° to 89.9°. Required: the tool does not calculate until every input is valid.
Example
The form opens with 10° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Effect on the result
As the angle approaches zero the output force rises very steeply.
Get it right
Measure from the output line, not from the direction of the applied force.

Method and formulas

  1. From the handbook relation 2R sin α = P cos α: output R = P ÷ (2 tan α).
  2. Each link carries P ÷ (2 sin α).
  3. Example: 500 N at 10° gives 1,417.8 N output, a mechanical advantage of 2.8356.

Limitations

  • Frictionless pins and rigid links; near the straight position, elasticity and clearances limit the real force.
  • The output force grows without limit as the angle approaches zero in theory only.
  • Example values are illustrations. Replace them with values for your actual task.

Typical uses

  • Size toggle clamps and press linkages
  • Show how force rises near the straight position
  • Check actuator force for a toggle

Who it is for

  • Design engineers
  • Maintenance engineers
  • Machine builders

What you get

  • Output force
  • Mechanical advantage
  • Force on each link

Interpreting the result

  • Design the frame and pins for the force at the smallest working angle.

References

  • Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 172–174. Topic reference; no source tables or recommended settings are reproduced.

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Open the Toggle Joint Force calculator