Dock Leveler “Stump-Out” is a problem associated with all mechanical (spring-powered) and power-assisted dock levelers that employ mechanical, retractable safety legs for free-fall protection. The legs can interfere with leveler movement during loading/unloading resulting in a situation that can slow productivity and cause injury to the forklift driver, damage to the leveler and product, and damage to the forklift.
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| • When a forklift enters a trailer with a load the weight of the load causes the trailer bed to lower.
• Mechanical safety legs hit their support posts. Leveler platform cannot follow trailer bed down.
|  | Additional Stump-Out Resources
Watch a video on Dock Leveler Stump-Out -
56K (Dial-Up), 150K (modem), 300K (DSL)
Brochure on Dock Leveler Stump-Out
Upgrade your mechanical dock leveler to a hydraulic dock leveler to avoid stump-out |
| • The leveler lip adopts steep slope to reach trailer bed. | |
| • When leaving the trailer, the forklift must impact a steep leveler slope.
• Smooth transition out of the trailer has been lost. | |
Other issues associated with Stump-Out:
• Repeated impact to steep lip can cause forklift driver back and neck injuries.
• Forklift and load are jarred. Forklift steering linkage, tires and counterweight can be damaged.
• Severe impact to leveler lip can damage leveler platform, lip hinge, front header and rear hinge.
Stump-out problems have been growing steadily worse in recent years as trailer bed heights get lower and more trailers are equipped with air-ride suspensions. Currently the only sure way to avoid stump-out problems is by using hydraulic dock levelers.
What are safety legs for?
Mechanical safety legs found on mechanical and power-assisted levelers are in place to stop the rapid descent of the leveler at dock level should the truck suddenly depart while the forklift was on the leveler platform. All levelers are required to have a form of free-fall protection.
Since hydraulic levelers don’t have these legs (they use a hydraulic velocity fuse for free-fall protection instead), there are no legs to interfere with leveler movement (free-float) during loading or unloading. Stump-out is avoided on hydraulic levelers. |
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