|
US908866A
|
|
Air-lock.
|
|
US922431A
|
|
Tunneling apparatus.
|
|
US838341A
|
|
Process of calking.
|
|
US834745A
|
|
Shield for tunnels.
|
|
US824668A
|
|
Calking apparatus for tunnels.
|
|
US820872A
|
|
Traveling hoist.
|
|
US811404A
|
|
Apparatus for erecting tunnels.
|
|
US806611A
|
|
Wagon-dumping mechanism.
|
|
US794635A
|
|
Apparatus for erecting tunnels.
|
|
US797817A
|
|
Air-lock apparatus for caissons.
|
|
US794632A
|
|
Tunneling-shield.
|
|
US797816A
|
|
Air-lock apparatus for tunnels.
|
|
US794633A
|
|
Tunneling-shield.
|
|
US797815A
|
|
Air-lock apparatus for caissons and tunnels.
|
|
US794634A
|
|
Tunneling-shield.
|
|
US780804A
|
|
Grappling device for handling steel segments, beams, &c.
|
