Apparatus for making foundry moulds

Abstract

Apparatus for continuous, high speed production of foundry mould parts by pressing them from a continuous bed of foundry sand mix which is based on a curable binder, pressing of the part being carried out at a time when the mix has adequate plastic flowability for pressure moulding and adequate potential curability to assure a strong, rigid cured product. Advantageous embodiments include curing means operating in conjunction with the pressing means.

What is claimed is: 
     
       1. In an apparatus for high speed production of foundry mould parts from a curable sand mix having adequate plastic flowability for pressure moulding, the combination of an endless horizontal conveyor extending from a mix depositing station to a forming station;   means at the mix despositing station for depositing the sand mix on the conveyor and forming the deposited mix into a bed of predetermined depth;   .Iadd.drive .Iaddend.means connected to said conveyor to drive the same stepwise to advance the bed of sand mix from the depositing station to the forming station in steps of equal length;   a press unit located at the forming station and comprising a flat support operatively arranged with respect to said conveyor to rigidly support against downward movement the portion of the bed of sand mix presented at the forming station by stepwise advance of the conveyor,   a pattern carrier,   .[.a bed severing device, and.].   .Iadd.a combination shroud and bed severing device, and .Iaddend.   vertically acting power means connected to said pattern carrier and said .Iadd.combination shroud and .Iaddend.bed severing device to drive the same downwardly toward said flat support and to return the same upwardly to positions adequately spaced above said conveyor to allow unimpeded movement of said bed of sand mix at the forming station,   said .[.bed severing device inclusing a portion which extends transversely of the conveyor in a position to sever from the trailing portion of the bed a portion of the bed adequate for the mould part to be formed..]. .Iadd.combination shroud and bed severing device comprising two flat mutually parallel wall members extending transversely of said conveyor and spaced apart by a distance such that the edges of said wall members which are directed toward the conveyor are separated by a distance substantially equal to the length of said equal steps through which the conveyor is driven, the one of said two wall members which is nearer the mix depositing station being operative as a severing device to sever from the trailing portion of the bed a portion of the bed adequate for the mould part to be formed, .Iaddend.   said power means being capable of operation, in response to completion of a step of movement of the bed by said conveyor, to drive said .Iadd.combination shroud and bed .Iaddend.severing device downwardly into engagement with the conveyor.Iadd., whereupon the severed portion of the bed is laterally confined by said combination shroud and bed severing device, .Iaddend.and to drive said pattern carrier downwardly to press the severed portion of the sand mix into the shape determined by a pattern carried by said pattern carrier. .[.2. The combination according to claim 1, wherein said pattern carrier is of rectangular plan configuration and is so arranged that two sides thereof are transverse to said conveyor; and     said bed severing device comprises four severing elements arranged to define a hollow rectangle of such size and configuration that said pattern carrier, and the pattern carried thereby, can move vertically within and independently of said bed severing device..]. .[.3. The combination according to claim 2, wherein said power means is a single power device connected to drive said pattern carrier; and   said bed severing device is mounted on said pattern carrier by means including a yieldable connection operative to allow said pattern carrier to continue its downward movement after said bed shearing device has   
     
     
        engaged said conveyor..]. 4. The combination according to claim .[.2.]. .Iadd.1 .Iaddend.wherein said power means comprises a first power device connected to said pattern carrier, and   power means, in addition to said first power device, .Iadd.comprising at least one power device .Iaddend.connected to said .Iadd.combination shroud and .Iaddend.bed severing device,   said pattern carrier and said .Iadd.combination shroud and .Iaddend.bed severing device being mounted for vertical movement independently of each   
     
     
        other. 5. The combination defined in claim 4, wherein said additional power means includes two power devices each connected to a different one of .Iadd.said .Iaddend.two mutually parallel .[.ones of said severing elements.]. .Iadd.wall members. .Iaddend. .[.6. The combination defined in claim 1, wherein said conveyor extends beyond said forming station, each step of operation of said conveyor being effective to remove from the forming station the mould part formed by the preceding cycle of operation of said press as well as to advance the leading end portion of the sand   
     
     
        mix bed into operative position at the forming station..]. 7. The combination defined in claim .[.6.]. .Iadd.1 .Iaddend.wherein said conveyor comprises an endless belt, the horizontal upper run of which extends from the forming station through a curing station,   the combination further including   a flat support member located at the curing station and over which the upper run of the conveyor belt extends;   means located above said conveyor at the curing station and defining a curing chamber, said means comprising, a rigid top wall,   two rigid mutually parallel side walls, and   two rigid mutually parallel end walls,   said side walls being spaced apart by a distance smaller than the width of the conveyor belt,   said end walls being spaced apart by a distance equal to a multiple of the length of each step of advance of the conveyor,   the lower edges of said side and end walls defining an open bottom for said curing chamber;     means mounting said curing chamber for vertical movement between a raised position, in which the lower edges of said side and end walls are spaced above the conveyor to allow free passage of mould parts through the curving station, and a lower position, in which the lower edges of said plates engage said conveyor belt in fluid-tight sealing fashion in opposition to said flat support member, said curing member being so positioned lengthwise of said conveyor that, when said curing chamber is moved into engagement with the conveyor belt at a time between steps of movement of the conveyor belt, said end walls will enter the respective spaces between adjacent pairs of moulded parts and a plurality of mould parts will be enclosed in said curing chamber;     power means for moving said curing chamber between said two positions; and   means for introducing a curing gas under pressure into said curing chamber   
     
     
        when said side walls and end walls engage said curing chamber. 8. The combination defined in claim 7 and further comprising releasable lock-down means operatively arranged to lock said curing chamber   
     
     
        against the combination of the conveyor belt and said support member. 9. The combination defined in claim 7 and further comprising means for evacuating said curing chamber, and the mould parts enclosed   
     
     
        therein, prior to introduction of the curing gas. 10. The combination defined in claim 7, wherein said .Iadd.combination shroud and .Iaddend.bed severing device comprises four flat severing plates arranged to define a hollow rectangle of such size and shape as to surround said pattern carrier, one end wall of said curing chamber serving as one of said severing plates.