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Walking Floors

Short answer: A moving-floor trailer unloads itself through the back doors without tipping. The floor is made of long slats, usually aluminum, split into three interleaved groups and driven by hydraulic cylinders under the trailer.

All the slats slide rearward together, carrying the load a short distance. Then the groups pull forward one at a time. Because two-thirds of the floor is always holding still, friction keeps the load from sliding forward with the moving third. Repeating the cycle 'walks' the cargo out the back. 'WALKING FLOOR' is a trademark of KEITH Manufacturing of Oregon. Its founder, Keith Foster, introduced the first commercially viable all-hydraulic moving floor for semi-trailers in 1973, and other makers sell similar 'moving floor' or 'live floor' systems. Because the trailer never tips, it can unload under low roofs or on uneven ground. It's widely used for wood chips, bark, biomass, waste, scrap, recycling and farm produce.

VideoWrite-up3 sources

In collections:Engineering Oddities

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What should you know about Walking Floors?

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. A walking floor moves the load while two-thirds of the slats hold still.

    DD-665-F01 · Write-up · Exhibit B (The cycle)

  2. KEITH introduced its WALKING FLOOR system in 1973.

    DD-665-F02 · Write-up · Exhibit D (Where it came from)

Video transcript: Walking Floors: Unloading Without Tipping

DID YOU KNOW? Walking floors in truck beds are a specialized type of moving floor system, designed to unload bulk materials efficiently without tipping the trailer. The floor is made of a series of interlocking slats that move in a continuous sequence, pushing cargo such as wood chips, agricultural products, or waste toward the rear of the truck while the upper surface stays level for stability.

Burned-in captions, read frame by frame (see transcript.md) · 19.1s Reel ·

Video coming soonWalking Floors · Instagram Reel
Walking Floors: Unloading Without Tipping Instagram Reel · · 19.1s

The write-up

Unloading without tipping. Hydraulic slats shuffle the load out the back.

  1. Exhibit A

    The slats

    The floor is long hydraulic slats, usually aluminum, split into three interleaved groups.

  2. Exhibit B

    The cycle

    All the slats slide rearward together, carrying the load. Then each third pulls forward on its own while the other two hold the load by friction.

  3. Exhibit C

    No tipping

    The trailer stays level, so it can unload under low roofs, indoors or on soft ground.

  4. Exhibit D

    Where it came from

    KEITH Manufacturing introduced the first commercially viable all-hydraulic moving floor for semi-trailers in 1973.

  5. Exhibit E

    A brand name

    'WALKING FLOOR' is KEITH's trademark. Similar systems are sold as moving or live floors.

Questions people ask about Walking Floors

How does a walking-floor trailer unload?

Hydraulic slats walk the load out.

Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

Into how many groups are the slats usually split?

Three interleaved groups.

Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

What stops the load sliding forward when slats retract?

Two-thirds of the floor holds still.

Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

What drives the slats?

Hydraulics under the floor.

Source: Write-up · Exhibit C (No tipping) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers; KEITH Manufacturing Co.: WALKING FLOOR official site

When did KEITH introduce its WALKING FLOOR system?

1973.

Source: Write-up · Exhibit D (Where it came from) · Trailer Magazine (Jun 1, 2023): Fifty years of innovation, KEITH Walking Floor

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. How does a walking-floor trailer unload?

    1. Slats walk the load out the back
    2. The trailer tips up
    3. A conveyor belt lifts it out
    4. A crane lifts it out
    Show the answer

    Answer: A. Slats walk the load out the back Hydraulic slats walk the load out. Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

  2. Into how many groups are the slats usually split?

    1. Three
    2. Two
    3. Ten
    4. One
    Show the answer

    Answer: A. Three Three interleaved groups. Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

  3. What stops the load sliding forward when slats retract?

    1. Friction on the other two-thirds
    2. A front wall pushes it back
    3. Magnets
    4. Straps
    Show the answer

    Answer: A. Friction on the other two-thirds Two-thirds of the floor holds still. Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers

  4. What drives the slats?

    1. Hydraulic cylinders
    2. Electric fans
    3. Springs
    4. Gravity
    Show the answer

    Answer: A. Hydraulic cylinders Hydraulics under the floor. Source: Write-up · Exhibit C (No tipping) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers; KEITH Manufacturing Co.: WALKING FLOOR official site

  5. When did KEITH introduce its WALKING FLOOR system?

    1. 1973
    2. 1923
    3. 1999
    4. 2015
    Show the answer

    Answer: A. 1973 1973. Source: Write-up · Exhibit D (Where it came from) · Trailer Magazine (Jun 1, 2023): Fifty years of innovation, KEITH Walking Floor

Cite this case file

Easterling, Marcus. "Walking Floors." The Detail Department (DetailEnjoyer), case file DD-665, last updated Oct 22, 2025. https://detailenjoyer.com/case/walking-floors/

Permalink: https://detailenjoyer.com/case/walking-floors/ · Last updated

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Cite a single fact by its ID, for example DD-665-F01 → https://detailenjoyer.com/case/walking-floors/#DD-665-F01

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