UNT Libraries Government Documents Department - 3 Matching Results
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- Ballot-Voting Machine
- Patent for a ballot box that counts the number of votes in the box.
- Drill-Collar.
- Patent for improved drill collar for "connecting a drill shank to the pipe" (lines 11-12).
- Pipe-Grapple.
- Patent for an improved pipe gripping mechanism which engages the interior of a pipe or tube.