# Sprinkle Of Truth (DD-581)

> The sprinkler in the footage is an impact sprinkler, the classic 'tick-tick-tick' design on farm risers. Water under pressure leaves the main nozzle as a jet. A spring-loaded drive arm sits in front of it with a small deflector, or spoon, that dips into the stream. The jet knocks the arm aside, the spring swings it back, and it strikes the sprinkler body. Each strike nudges the head around a few degrees, so the jet sweeps a circle (or an arc, with trip stops) in small, even steps. Breaking up the stream this way also spreads the water more evenly across the wetted area. Other rotary sprinklers use a turbine or gear drive instead, as the Reel says. Orton Englehart, a citrus grower in Glendora, California, built the horizontal-action impact drive sprinkler in his shed around 1932 to 1933. His neighbor Clem LaFetra urged him to patent it. The application was filed on December 18, 1933, and US Patent 1,997,901 was granted on April 16, 1935. Englehart preferred farming and sold the rights to Clem and Mary LaFetra, who began production in their family barn on October 13, 1935, under the name Rain Bird. In 1990, the American Society of Agricultural Engineers named the Rain Bird impact sprinkler a historic landmark of agricultural engineering, crediting it with helping sprinkler irrigation spread to more than 50 million acres worldwide. The footage shows an impact sprinkler on a tripod stand in a sandy field, its arm swinging as the jet sprays across the sand.

- Department: Tech
- First published: 2025-05-26
- Last updated: 2025-05-26
- Permalink: https://detailenjoyer.com/case/sprinkle-of-truth/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## On the timeline

- **Dec. 18, 1933**: Orton Englehart files his impact sprinkler patent
- **April 16, 1935**: US Patent 1,997,901 is granted
- **Oct. 13, 1935**: Production begins in the LaFetra family barn
- **1990**: ASAE names the Rain Bird impact sprinkler a historic landmark

Full timeline: https://detailenjoyer.com/timeline/?case=sprinkle-of-truth

## Quick facts

- **DD-581-F01**: In an impact sprinkler, a spring-loaded arm knocked aside by the jet strikes the body and turns the head in small steps. _(Write-up · Exhibit A (Spring, spoon, strike))_
- **DD-581-F02**: Orton Englehart's impact sprinkler patent was granted on April 16, 1935. _(Write-up · Exhibit C (Patented in 1935))_

## Write-up

A sprinkler that hits itself. The impact sprinkler, patented in 1935, became Rain Bird's first product.

1. **Spring, spoon, strike**: The jet knocks a spring-loaded arm aside. It swings back, strikes the body and turns the head a notch.
2. **A citrus grower's idea**: Glendora citrus grower Orton Englehart built the impact sprinkler in the early 1930s.
3. **Patented in 1935**: His patent was filed on December 18, 1933, and granted on April 16, 1935.
4. **Rain Bird**: The LaFetras bought the rights and began production in their barn on October 13, 1935.
5. **A landmark**: ASAE named the Rain Bird impact sprinkler a historic landmark of agricultural engineering in 1990.

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## Reel vs. record

- **Note**: 'This stream hits a small turbine or hammer-like arm': both designs exist. The footage shows the hammer type, an impact sprinkler. The jet knocks the spring-loaded arm aside, and the arm swings back and strikes the body, turning the head a few degrees each time.
- **Note**: 'Deflects the flow and causes the sprinkler to spin': in an impact sprinkler, the head steps around in small increments rather than spinning continuously.
- **Missing**: citrus grower Orton Englehart invented the impact sprinkler in the early 1930s. His patent was granted on April 16, 1935, and it became the first product of Rain Bird.

## Video: Sprinkle Of Truth: A Sprinkler That Hits Itself

- Duration: 21.7 s · Published: 2025-05-26
- File: https://detailenjoyer.com/assets/videos/DKI1ukWRfCH.mp4

### Transcript

DID YOU KNOW? Non pop-up irrigation sprinklers, often used in agricultural or industrial settings, typically operate using water pressure to drive a rotating mechanism or oscillating arm. Water enters the sprinkler head through a hose or pipe, and is forced through a nozzle, creating a jet stream. In rotary sprinklers, this stream hits a small turbine or hammer-like arm that deflects the flow and causes the sprinkler to spin. NOW YOU KNOW!

## Questions & answers

**Q: What turns the head of an impact sprinkler?**  
A: Each strike nudges it a few degrees. _(Source: Write-up · Exhibit A (Spring, spoon, strike) · Irrigation Today: The invention that changed irrigation; Google Patents: US1997901A, Water sprinkler (Englehart, 1935))_

**Q: Who invented the impact sprinkler?**  
A: A citrus grower in Glendora, California. _(Source: Write-up · Exhibit B (A citrus grower's idea) · ASABE: Rain Bird Impact Drive Sprinkler Head, historic landmark (1990); Irrigation Today: The invention that changed irrigation)_

**Q: When was the impact sprinkler patent granted?**  
A: On April 16, 1935. _(Source: Write-up · Exhibit C (Patented in 1935) · Irrigation Today: The invention that changed irrigation; Journal of Irrigation and Drainage Engineering: Seventy-Fifth Anniversary of Horizontal Action Impact Drive Sprinkler (2009); Google Patents: US1997901A, Water sprinkler (Englehart, 1935))_

**Q: Which company made the impact sprinkler its first product?**  
A: Founded by Clem and Mary LaFetra. _(Source: Write-up · Exhibit D (Rain Bird) · ASABE: Rain Bird Impact Drive Sprinkler Head, historic landmark (1990); Journal of Irrigation and Drainage Engineering: Seventy-Fifth Anniversary of Horizontal Action Impact Drive Sprinkler (2009))_

**Q: Where did production of the first impact sprinklers begin?**  
A: On October 13, 1935. _(Source: Write-up · Exhibit D (Rain Bird) · ASABE: Rain Bird Impact Drive Sprinkler Head, historic landmark (1990); Journal of Irrigation and Drainage Engineering: Seventy-Fifth Anniversary of Horizontal Action Impact Drive Sprinkler (2009))_

## Sources

- [ASABE: Rain Bird Impact Drive Sprinkler Head, historic landmark (1990)](https://asabe.org/About-Us/About-ASABE/History/ASABE-Historic-Landmarks/Rain-Bird-Impact-Drive-Sprinkler-Head-1990)
- [Irrigation Today: The invention that changed irrigation](https://irrigationtoday.org/features/the-invention-that-changed-irrigation/)
- [Journal of Irrigation and Drainage Engineering: Seventy-Fifth Anniversary of Horizontal Action Impact Drive Sprinkler (2009)](https://doi.org/10.1061/(ASCE)0733-9437(2009)135:2(133))
- [Google Patents: US1997901A, Water sprinkler (Englehart, 1935)](https://patents.google.com/patent/US1997901A/en)

## Cite this case file

Easterling, Marcus. "Sprinkle Of Truth." The Detail Department (DetailEnjoyer), case file DD-581, last updated May 26, 2025. https://detailenjoyer.com/case/sprinkle-of-truth/