# Platform Lift Application

## Application Description

A manufacturer is looking for linear motion systems that can periodically raise and lower a cylindrical mixer eight inches during the mixing cycle to allow product testing to insure product quality and consistency. The cylinder weighs 1,700 lbs and is mounting on a movable cart allowing for the final product to be moved to a dispensing station. The customer wants a 4 times safety factor with respect to capacity. The solution for this application involves worm screw jack systems.

## Step 1: Determine Specifications

• Single motor and drive
• The load will be in tension
• Total travel 8 inches
• 4 times safety factor
• 8 inches in 5 seconds

## Step 2: Analysis

### Configuration:

To minimize the size of the motor drive, a Ball Screw jack will be used. Based on the mounting frame, the inverted rotating configurations will be used.

### Column Strength:

The jacks will be loaded in tension, therefore column strength does not need to be considered.

### Speed and Horsepower:

Using a standard 1750 AC Motor and the 2.5HL-BSJ with the 12:1 gear ratio, full travel would be reached in 3.5 seconds. Using the horsepower formulas on page 15 of our Worm Gear Screw Jacks Catalog, a 2 HP AC motor running at 1750 rpm will be adequate for the requirements.

 HPper jack = .0244 in-lb × 566 lb × 1,725 rpm = .38 hp / jack 63,025
 HParrangement = .38 hp per jack × 3 jacks = 1.55 total hp .9 × (.9)2

The longest center to center distance between the jack and gearbox is 24 inches, leaving a shaft length of 17 inches. Using the formula on page 189 based on Torsional Twist, the proper Line Shafting to use would be the LJ-8.

 NSpeed = .6692 × ( π )2 × 3.895 × 105 = 44,547 rpm 17 in
 NTwist = 41.48 in-lb × ( 17 in ) = .57o 1,235

## Step 3: Product Selection

### Create a Reference Number for the Assembly

From page 31, create reference numbers for the following: three 2.5 ton ball screw jacks, inverted rotating configuration, 12:1 worm gear ration, 15 inches "L" dimension.

### Jacks:

• (3) 2.5-BSJ-IR 12:1/SSE-1/SSE-2/FA/15/S

### Gearboxes:

• (2) GB210 Type D

### Shafting:

• (2) LJ-8 17" OAL
• (1) LJ-8 12" OAL

### Couplings:

• (3) P-2200-XX (½ - ½)
• (5) P-2200-178 (¾ - ¾)

### Motor:

• 2 HP AC Motor 1750 rpm
Figure 1

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