Effort Required in Lifting Load with Acme Threaded Screw Calculator

Effort Formula:

\[ P_{li} = W \times \left( \frac{\mu \times \sec(0.253) + \tan(\alpha)}{1 - \mu \times \sec(0.253) \times \tan(\alpha)} \right) \]

Effort in Lifting Load (P_li): N

1. What is Effort in Lifting Load with Acme Thread?

Definition: This calculator determines the force required to lift a load using an Acme threaded screw, accounting for friction and helix angle.

Purpose: It helps mechanical engineers and designers calculate the effort needed for screw jacks, vises, and other lifting mechanisms.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ P_{li} = W \times \left( \frac{\mu \times \sec(0.253) + \tan(\alpha)}{1 - \mu \times \sec(0.253) \times \tan(\alpha)} \right) \]

Where:

\( P_{li} \) — Effort in lifting load (Newtons)
\( W \) — Load on screw (Newtons)
\( \mu \) — Coefficient of friction at screw thread (dimensionless)
\( \alpha \) — Helix angle of screw (radians)
0.253 — Half of Acme thread angle (14.5° in radians)

Explanation: The formula accounts for the wedge effect of the Acme thread and the friction between the screw and nut.

3. Importance of Effort Calculation

Details: Proper effort estimation ensures the screw mechanism can handle the load without excessive force requirements.

4. Using the Calculator

Tips: Enter the load in Newtons, friction coefficient (default 0.15), and helix angle in radians (default 0.0785 rad ≈ 4.5°). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why is the 0.253 value fixed in the formula?
A: It represents half of the standard Acme thread angle (29°), converted to radians (14.5° = 0.253 rad).

Q2: What's a typical coefficient of friction for Acme threads?
A: Typically 0.10-0.20 for steel-on-steel, but varies with lubrication and materials.

Q3: How do I convert degrees to radians for the helix angle?
A: Multiply degrees by π/180 (e.g., 4.5° × π/180 ≈ 0.0785 rad).

Q4: Does this account for starting friction?
A: No, starting friction is typically higher - add 20-30% safety factor for practical applications.

Q5: What if my screw has a different thread angle?
A: For non-Acme threads, replace 0.253 with half your thread angle in radians.