MICHAEL PETRO
Engineers in Moon Twp, PA
License number
Pennsylvania PE009856E
Category
Engineers
Type
Professional Engineer
Address
Address
Moon Twp, PA 15108
Professional information
Temporary Mine Roof Prop
US Patent:
4167361, Sep 11, 1979
Filed:
Aug 30, 1978
Appl. No.:
5/938069
Inventors:
Michael Petro - Coraopolis PA
Joseph R. Betz - Zelienople PA
Duane W. DeArmitt - Butler PA
Joseph R. Betz - Zelienople PA
Duane W. DeArmitt - Butler PA
Assignee:
Mine Safety Appliances Company - Pittsburgh PA
International Classification:
E21D 1544
US Classification:
405290
Abstract:
The base member of a mine roof prop is provided with a closed lower chamber and an adjoining open-top upper chamber in which the lower end of a post is slidably mounted, with means at the upper end of the post for engaging a mine roof. A body of liquid is supported in the lower chamber by flexible means, below which there is an air inlet. The base member also has a liquid passage connecting the upper part of the lower chamber with the lower part of the upper chamber so that when compressed air is delivered to the air inlet, the flexible means will force liquid up through the passage and into the upper chamber to raise the post, whereupon a valve can be closed to trap the liquid in the upper chamber.