Phase: Static Force Evaluation
Opportunity: Sam has decided to move forward with a telescoping boom lift. Even after making this decision, he overwhelmed by the variety of telescoping boom lift sizes on the market. He chooses the company "Sky High Lifts" to manufacture a lift platform that can be customized to meet his requirements.
Because you have earned his trust during the research phase, he has hired you to help him better understand and customize this lift for his application. Sky High's standard boom frame can be customized for a maximum lift capacity of 2000 pounds along with a maximum extended boom length 40 feet. Sam wants to specify a reduced lift capacity and boom length to match his requirements and reduce the size and cost of various components (ex. drive system, counterweight, etc.). The layout the lift is shown below:
Additional specifications are listed below:
Sam has provided you with specific dimensional constraints ABX, ABY, BC, and L in the attached spreadsheet.
|
L(ft)
|
ABX(ft)
|
ABY(ft)
|
BC(ft)
|
|
25
|
3
|
1.5
|
6
|
- The boom has a travel range from θ = 0° to θ =70°
- The lift platform must support 800 lbs of people and equipment. In addition, the manufacturer's standard platform weighs 200 lbs for a total load of 1000 lbs at the platform.
- 'L' is the extended length of the boom. For simplicity in calculating the boom weight, assume the entire boom is made of a standard 10x4x)4" square structural steel channel.
- The wheel base is square (10 ft wide by 10 ft long).
- The motorized wheeled base portion of the lift weighs 1000 pounds with its CG centered on the lift's rotation axis.
- The rotation axis is also centered between the wheels.
- A counterweight will be positioned directly over the rear wheel as shown.
Assignment: Complete the following evaluation of your specific lift:
Use a spreadsheet to calculate static loads in 2° increments for the full travel range.
- Hydraulic cylinder force
- Static Forces at B (components and resultants)
Specify the following requirements for the system:
- Hydraulic cylinder retracted length, extended length, and total travel,
- Hydraulic cylinder maximum static load,
- Maximum static loads for the shaft and bearings at pivot B.
Specify the following details of the counterweight:
- Weight required for the counterweight to avoid tipping with a 1.5 times overload of people/equipment (800 lbs x 1.5 = 1200 lbs). Refer to the figure illustrating "Critical CG Locations".
- Sam will need to purchase a trailer to transport his boom lift. Before he chooses a trailer, he needs you to provide him with the total weight of the lift system.
Provide a summary of your Phase Static Force Analysis information. Scan in any supporting free body diagrams, hand calculations, etc.