This invention relates to transfer grids for metal plates.
When initially formed in a plate mill, metal plates are very hot and must be suitably cooled before further processing. A cooling bed is typically provided over which the plates are slid by the use of chains employing pusher dogs. The bed is constructed to allow plentiful air circulation to the plates for cooling as they traverse the length of the bed.
The cooling bed is typically composed of a plurality of transfer grids with each grid cast as a single piece. Each grid may typically comprise a plurality of parallel longitudinal grid members extending in the direction of travel of the plates and a plurality of transverse cross grid members extending between the longitudinal grid members. The longitudinal grid members project above the cross members so that the support surface for the plates as the plates move over the grid is defined by the longitudinal grid members.
The movement of the metal plates over the grid surfaces generates significant wear on the grid surfaces requiring relatively frequent replacement of the grids at considerable expense. In addition, the undersurfaces of the plates may be marred as they are conveyed along the grid members.
Various attempts have been made to modify the transfer grids to minimize grid wear and to minimize marring of the plates as they are transferred over the grid. For example, it has been proposed to provide inserts which are removably positioned, in retrofit manner, in the pockets defined between the longitudinal and transverse grid members with each insert, when positioned in a pocket in the grid, presenting a roller projecting above the surface of the longitudinal grid members so that the plates move along a plate pass plane defined by the upper surfaces of the rollers, whereby to minimize marring to the undersurfaces of the plates and eliminate wear on the transfer grid.
Whereas these inserts have proven to be helpful in reducing grid wear and minimizing marring of the plates, the available inserts have a complex construction, and hence a rather high cost; employ an adjusting arrangement for the insert roller that makes it difficult to position the roller at the precise desired height and/or to position the circumferential surface of the roller at a level disposition with respect to the grid surface; and require complete removal of the insert from the grid in order to allow replacement of the roller.