Scissor support for welding tank sections

An apparatus for supporting and rotating a pair of hollow tank sections of generally circular cross section, including scalene and frusto-conical tank sections, during welding of the sections in end-to-end abutting relation to form an elongated tank, including at least two longitudinally spaced, axially aligned, rotatable rings which define a welding cage;

• at least one ring including a plurality of circumferentially spaced, radially directed jacks to force the abutting edges of the tank sections into a precise circular cross section and support and hold the abutting edges in aligned relation during rotation and welding;
• said rings including radially directed jacks in the bottom for lifting the sections, to thereby support the tank sections for rotation about a common axis;
• a longitudinally extending conveyor which extends within the welding cage and on either side of the welding cage for moving adjacent tank sections longitudinally toward each other into abutting engagement for welding in the center ring, and for moving welded sections longitudinally of the cage, the improvement comprising:
• a support and lift assembly for tank courses located outboard of said cage to move the welded tank courses into position for another course to be welded on;
• said conveyor being discontinuous at one or more positions and a scissors support and lift assembly located at said discontinuous positions;
• said scissors support and lift assembly including a transversely extending base;
• a pair of transversely extending arms pivotably mounted respectively at each end of said base;
• said arms extending transversely and one arm crossing the other;
• a piston pivotably connected to one of the arms which extends generally horizontally into a cylinder extending horizontally pivotably connected to the other arm;
• course support means mounted at the end of each arm to support welded tank courses;
• a first vertical stability limit switch located on the upper surface of the lowest jack in said one ring;
• a second vertical stability limit switch located on a jack outboard of said center ring;
• whereby fluid pressure applied to said horizontal cylinder controlled by said first and second limit switches displaces the piston and moves said arms and course support means vertically to raise a tank course until vertically aligned with said upper surface of said lowest jack in said center ring.

A support and lift assembly for welded tank courses used to connect adjacent tank sections comprising:

• a scissors support and lift assembly located outboard of a tank cage;
• said scissor support including a pair of transversely extending arms;
• a piston pivotably connected to one of said arms which extends into a cylinder pivotably connected to the other said arm;
• roller support means rotatably mounted at the end portion of each said arm to support tank sections;
• limit switch means located at least partially within said cage for controlling the height of tank sections to be lifted;
• means for applying fluid pressure to said cylinder controlled by said limit switch means to displace said piston and move said arms and roller support means vertically to raise a tank section into connection position.

A support and lift assembly for connected tank sections comprising:

• a scissors support and lift assembly located outboard of a tank cage;
• said support and lift assembly further including a pair of transversely extending arms;
• a first piston pivotably connected to one of said arms which extends generally horizontally into a first horizontally extending cylinder pivotably connected to the other arm;
• tank support means rotatably mounted at the end portion of each arm to support connected tank sections;
• a second piston extending generally vertically between a base and one of the arms and extending into a second cylinder connected to the other of said base and arms;
• vertical height limit switch means in said cage for controlling the height of said tank sections;
• means for applying fluid pressure to said first horizontal cylinder controlled by said limit switch means whereby said piston is displaced and said arms and respective support means are moved vertically to raise a tank section into connecting position.