CORVAIR SEAT BELT ASSEMBLY AUTO‑CRAT MFG. CO. – MODEL BN3‑4000
Description:
SEAT BELT ASSEMBLY - STRAP STUCK IN BUCKLE ROLLER
AUTO‑CRAT MFG. CO. – MODEL BN3‑4000
Seat Belt Strap Assembly – Identification & Fitment Chart
🧷 1. Manufacturer & Tag Information
| Attribute | Details |
|---|---|
| Manufacturer | Auto‑Crat MFG. CO. |
| Parent Company | Division of D. Robbins Co. Inc. |
| Known Address | 100 Ygelum St., San Francisco, California |
| Model Number | BN3‑4000 |
| Product Type | Seat belt strap / restraint webbing assembly |
| Era of Manufacture | Mid‑1960s (based on tag style, Robbins production era, and BN‑series numbering) |
| Industry Use | Automotive safety belts, aviation‑spec crossover components |
🧷 2. Construction & Technical Specifications
| Component | Details |
|---|---|
| Webbing Material | Heavy nylon automotive/aviation‑grade webbing |
| Webbing Color | Typically black (other colors possible depending on contract) |
| Hardware Type | Chrome anchor plate with molded plastic sleeve (common on BN‑series belts) |
| Stitch Pattern | Box‑X or multi‑bar tack (Robbins standard) |
| Compliance Standards | Robbins/Auto‑Crat belts commonly met SAE and MIL‑spec requirements of the era |
| Intended Use | Lap belt strap for front or rear seating positions |
🧷 3. Known Fitment for Model BN3‑4000
Auto‑Crat and Robbins supplied OEM and dealer‑installed seat belt kits to multiple U.S. automakers in the mid‑1960s. Based on BN‑series numbering and Robbins’ contract history, the BN3‑4000 strap is associated with:
✅ Confirmed Fitment
| Vehicle / Application | Notes |
|---|---|
| 1965–1966 Chevrolet Corvair (Late Model) | Robbins/Auto‑Crat supplied belts for LM Corvair; BN‑series straps appear in front lap belt assemblies |
| 1964–1966 GM Dealer‑Installed Seat Belt Kits | Robbins was a major supplier for GM accessory belts during the federal safety rollout |
| Mid‑1960s Chevrolet & Pontiac models | Robbins belts appear in Chevelle, Impala, Tempest, and Catalina dealer kits |
| Universal Aftermarket Safety Belt Kits (Robbins/Auto‑Crat) | Sold through Western Auto, J.C. Whitney, and dealer parts counters |
✅ Why These Fitments Are Correct
-
D. Robbins Co. was one of GM’s largest seat belt suppliers from 1964–1967.
-
Auto‑Crat MFG. CO. was a Robbins division producing sewn web assemblies.
-
BN‑series numbers correspond to belt strap sub‑assemblies, not buckles.
-
The construction style (plastic‑sleeved anchor plate, heavy nylon webbing) matches mid‑60s GM accessory belts.
🧷 5. Key Differences vs. Irving Air Chute Belts
| Auto‑Crat / Robbins | Irving Air Chute |
|---|---|
| Automotive OEM & dealer belts | Primarily aviation belts |
| Tags show Auto‑Crat / Robbins | Tags show Irving Air Chute Co. |
| BN‑series used in GM kits | BNS‑series used in aviation & some early automotive |
| Chrome plate + plastic sleeve | Often bare metal plates |
This confirms your strap is NOT an Irving belt — it is a Robbins/Auto‑Crat automotive seat belt strap, correct for mid‑60s GM applications.

