Patent Publication Number: US-4253636-A

Title: Concrete molding machine

Description:
BACKGROUND OF THE INVENTION 
     It is now common practice in the concrete or cementitious products industry to mold articles such as concrete blocks on various machines. 
     In these machines a mold of fixed dimensions is filled with concrete and then the mold is vibrated. Once compacted by the vibration, the molded article is pushed vertically downward out of the bottom of the mold having four walls which are fixed and immovable relative to one another. 
     So configured, these machines do not allow for a fast change in the dimensions of the article being molded. These machines and molds also require that the vertical sides of the article being molded be smooth and substantially vertical so that the molded article may be pushed downward out of the mold after compaction. 
     These machines of the art also do not allow for the inclusion of hollow members in a specified position in the molded concrete or cementitious article. 
     The object of the present invention is to remedy these shortcomings of the present art. 
    
    
     DRAWING DESCRIPTION 
     In FIG. 1 outer frame, 1, is supported by four pedestals, 6, which by means of expandable joints, 7, can be raised and lowered vertically. Horizontal arms, 2, connect the frame, 1, to the longer sides, 4, and shorter sides, 5, of the mold. Expandable joints, 3, of all eight horizontal arms, 2, allow the sides of the mold to be retracted thereby freeing them from the molded article. 
    
    
     The molding cycle of the machine consists of lowering frame, 1, by means of expandable joints, 7, with expandable joints, 3, expanded so that sides 4 and 5 abut one another and rest on a steel plate, not shown, forming a rectangular mold open only at its upper surface. 
     Tube, 10, may then be lowered between the sides, 4, as shown in FIG. 1. Then tube supporting members, 8, are extended by means of expandable joints, 9, through holes, 11, in sides, 4. The tube, 10, is thus firmly held in place by tube supporting members, 8. 
     Concrete or other cementitious material is thereby introduced into the mold through the open upper surface of the rectangular mold. The mold and frame, 1, are then vibrated to release air from the concrete and compact it. 
     Tube supporting members, 8, are then retracted by means of expandable joints, 9, through holes, 11, in sides 4 of the mold. 
     Sides 4 and 5 of the mold are then retracted toward the outer frame, 1, by means of expandable joints, 3, in support arms, 2. Outer frame, 1, is then raised by means of expandable joints, 7, in supporting pedestals, 6. The molded concrete article is then transported to curing ovens on the metal plate which formed the bottom of the mold. 
     Alternatively, sides 4 and 5 may remain with the molded article and the bottom plate of the mold during transport to curing ovens and during the subsequent curing, if before retraction of supporting arms, 2, sides 4 and 5 are disengaged from said supporting arms. 
     It is also within the scope of the invention, that instead of lowering frame 1 and sides 4 and 5 onto a steel plate, the steel plate may be raised to contact the lower edges of sides 4 and 5 to form the bottom of the mold.