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                        1740324
                    
                                            
                                - 
                                    Patent number 1,740,324
                                
 
                                - 
                                    Issue date Dec 17, 1929
                                
 
                        
                                                                
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                                    B28 - WORKING CEMENT, CLAY, OR STONE
                                 
                        
                 
             
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                        1729602
                    
                                            
                                - 
                                    Patent number 1,729,602
                                
 
                                - 
                                    Issue date Oct 1, 1929
                                
 
                        
                                                                
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                                    B28 - WORKING CEMENT, CLAY, OR STONE
                                 
                        
                 
             
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                        1632938
                    
                                            
                                - 
                                    Patent number 1,632,938
                                
 
                                - 
                                    Issue date Jun 21, 1927
                                
 
                        
                                                                
                                - 
                                        
                                    B28 - WORKING CEMENT, CLAY, OR STONE