# Walking Floors (DD-665)

> 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.

- Department: Tech (also Cars)
- First published: 2025-10-22
- Last updated: 2025-10-22
- Permalink: https://detailenjoyer.com/case/walking-floors/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## On the timeline

- **1973**: KEITH Manufacturing introduces the WALKING FLOOR unloading system

Full timeline: https://detailenjoyer.com/timeline/?case=walking-floors

## Quick facts

- **DD-665-F01**: A walking floor moves the load while two-thirds of the slats hold still. _(Write-up · Exhibit B (The cycle))_
- **DD-665-F02**: KEITH introduced its WALKING FLOOR system in 1973. _(Write-up · Exhibit D (Where it came from))_

## Write-up

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

1. **The slats**: The floor is long hydraulic slats, usually aluminum, split into three interleaved groups.
2. **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. **No tipping**: The trailer stays level, so it can unload under low roofs, indoors or on soft ground.
4. **Where it came from**: KEITH Manufacturing introduced the first commercially viable all-hydraulic moving floor for semi-trailers in 1973.
5. **A brand name**: 'WALKING FLOOR' is KEITH's trademark. Similar systems are sold as moving or live floors.

## Related case files

- [Piston Pumps (DD-072)](https://detailenjoyer.com/case/piston-pumps/): Another hydraulic workhorse
- [Counter Crane (DD-687)](https://detailenjoyer.com/case/counter-crane/): Another case about moving heavy loads safely
- [Food Recycling (DD-569)](https://detailenjoyer.com/case/food-recycling/): The trailers that haul bulk waste and feed
- [Earth Movers II (DD-639)](https://detailenjoyer.com/case/earth-movers-ii/): Another way to move bulk material

## Reel vs. record

- **Mechanism**: the slats don't move in one 'continuous sequence'. All of them push the load rearward together, then each third retracts on its own while the other two-thirds hold the load by friction.
- **Note**: 'Interlocking': the slats sit side by side in three alternating groups and are sealed against each other. They slide independently rather than locking together.
- **Power**: the slats are driven by hydraulic cylinders under the floor, which the Reel doesn't mention.
- **Name**: 'WALKING FLOOR' is a KEITH Manufacturing trademark (since 1973). Generic terms are moving floor or live floor.
- **Note**: Trailers, not truck beds: the system is mostly built into semi-trailers, though some rigid trucks use it too.

## Video: Walking Floors: Unloading Without Tipping

- Duration: 19.1 s · Published: 2025-10-22
- File: https://detailenjoyer.com/assets/videos/DQH65T_kmXJ.mp4

### Transcript

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.

## Questions & answers

**Q: How does a walking-floor trailer unload?**  
A: Hydraulic slats walk the load out. _(Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers)_

**Q: Into how many groups are the slats usually split?**  
A: Three interleaved groups. _(Source: Write-up · Exhibit A (The slats) · Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers)_

**Q: What stops the load sliding forward when slats retract?**  
A: 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)_

**Q: What drives the slats?**  
A: 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)_

**Q: When did KEITH introduce its WALKING FLOOR system?**  
A: 1973. _(Source: Write-up · Exhibit D (Where it came from) · Trailer Magazine (Jun 1, 2023): Fifty years of innovation, KEITH Walking Floor)_

## Sources

- [Commercial Motor (Sep 1, 2005): How they work, moving-floor trailers](https://archive.commercialmotor.com/article/1st-september-2005/55/how-they-work-moving-floor-trailers-comprise-a-ser)
- [Trailer Magazine (Jun 1, 2023): Fifty years of innovation, KEITH Walking Floor](https://www.trailermag.com.au/fifty-years-of-innovation-keith-walking-floor/)
- [KEITH Manufacturing Co.: WALKING FLOOR official site](https://www.keithwalkingfloor.com/)

## 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/