Boom Lift Equipment Reduces Leaks
How One Company’s Re-engineered Hydraulic Hose Assemblies Eliminated Leaks and Reduced Costs by 17%
Problem: Hydraulic Hose Assembly Leaks
A boom lift (also called a man-lift) uses hydraulic power to elevate a worker into the air on a caged platform. One manufacturer’s model had a working height of more than 40 feet and a horizontal reach exceeding 22 feet, so the hydraulic hose assemblies underwent a great deal of stretching and flexing, leading to a problem with leaks.
The manufacturer approached Motion Industries, a Gates distributor, for help with eliminating the leaks. At the same time, their engineers wanted to take some cost out of the hydraulic hose kit on the machine. Motion Industries turned to Gates for application engineering advice.
Tim Deans, Gates Engineering Project Manager, visited the plant to see how the man-lift was being assembled. Following his fact-finding mission, he arranged to ship a unit to Gates Customer Solutions Center (CSC) in Englewood, Colorado. In a secure bay at the CSC, Gates engineers performed Value Engineering/Value Analysis (VE/VA), going over the machine from top to bottom.
This particular man-lift is a 4-wheel drive vehicle, with all wheels driven by a hydraulic motor. Hoses emanate from the drive motor on the bottom of the vehicle and ascend the boom, connecting to a diesel engine with pumps that activate the articulated arm holding the work platform.
As the platform pivots, the hoses flex and rub against one another. The abrasion, snagging and pulling led to the hose leaking problem.
Solution: New Routing System Redesign
The first step in the VE/VA process was to take pressure and temperature measurements on the primary hydraulic circuits to determine if there were any problem areas. The testing verified that the hoses were operating at the nominal pressure and temperature level, between 160°F and 180°F. The machine was plumbed with Gates Megasys® M3K hoses rated for 3,000 psi working pressure.
Additional testing for this customer also confirmed that the hose kits supplied by Motion Industries met ISO 4406 cleanliness standards specified by the hydraulic pump manufacturer. The key cause of the leaking problems was traced to the routing scheme.
At the CSC, Gates engineers completely stripped the machine and designed a new routing system. In the process they replaced some couplings and adapters. They also devised a clamping arrangement for the bundled hoses that eliminated the need for special iron troughs that had been built into the boom arm to contain the hoses.
Re-plumbing the machine took almost 20 pounds of metal out of the boom, which allowed the man-lift work platform to carry a higher weight rating for man and tools. Altogether, Gates engineers re-routed all the boom hoses and about 50% of the machine hoses, eliminating the potential leak paths.
The new Bill of Materials (BOM) for the machine ended up reducing the total cost of the hose kit by approximately 13%. In addition, the re-engineering reduced the cost of the adapter kit by about 10 percent. Altogether, the assembly package supplied by Motion Industries on the machine was reduced by about 17%, making the man-lift more cost competitive in the marketplace and less prone to leakage.
In addition to reducing the cost of the man-lift platform, VE/VA provided the following benefits to the customer:
- Elimination of warranty concerns
- Higher perception of quality by end-user
- Better appearance resulting in end-user willingness to pay more
- Higher re-sale value