Instrumented Load Pins for Sheave Applications

Constant Wrap Angle

*Axis of Maximum Sensitivity: Align Keeper Flat of Load Sensing Pin perpendicular to Axis of Maximum Sensitivity which is at one half the wrap angle. For this example, wrap angle = 105 degrees and Ø/2 = 105 /2 = 52.5 degrees. See specification drawing below.

Ø= Wrap Angle
T = Line Tension
P = Resultant Force on Sheave Pin

Line Tension (T): To measure the tension in a line by measuring the reaction force on the sheave use the specification drawing and formulas:
P = 2T cos(Ø/2) or T = P ÷ 2cos(Ø/2)

Example:For a Wrap Angle of Ø = 105 and measured sheave load of 10,000-lbs. The Line Tension (T) can be determined by the formula:

Variable Wrap Angle

The cross section of the bi-axial load pin illustrates gage alignment. The gages marked Y will sense load component Py, while the gages marked X will sense loads in the Px direction. Given the outputs from the two bridges as Ex and Ey, and constants (Kx,Ky), derived from calibration data*, the resultant force P is determined by:

Px = Kx Ex
Py = Ky Ey
and the resultant force P = Square root of [Px]² + [Py]²

The Line Tension (T) and Wrap Angle (Ø) can be determined by:
T = Px² + Py² ÷ 2Px and Ø = 2 inverse cosine( P ÷ 2T)

*Where P, Px and Py are adjusted for cross-talk effects. For further discussion of bi-axial load pins see bi-axial pins under the Clevis Pin Optional Features

Variable Wrap Angle Specifications

Pin Design: For quotations on custom sheave pin designs, Contact Us at 610-825-3310 or complete our form. Include additional drawings, comments, or special requirements as applicable.

Full Specs