Lightweight trench box

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Information

Patent Grant
D252950

References
Source

Patent Number
D252,950
Date Filed
Monday, August 29, 1977
47 years ago
Date Issued
Tuesday, September 18, 1979
45 years ago

Inventors
- William F. Birchfield
Original Assignees
- AGL CORPORATION
Examiners
- Word; A. Hugo
Agents
- Carver; Stephen D.

US Classifications
- D25 - Building units and construction elements
Field of Search
- US
- D25 1
- D25 61
- D25 62
- D25 66
- D25 68
- D25 98
- 405 272
- 405 273
- 405 282
- 405 285
- 256 24
International Classifications
- Term of Grant
  14Years

Information

Abstract

Description

Claims

The ornamental design for a lightweight trench box, as shown.

US Referenced Citations (4)

Number	Name	Date	Kind
2188077	Dowd	Jan 1940
3335573	Ward	Aug 1967
4056940	Fisher	Nov 1977
4114383	Nieber	Sep 1978