RUBBER MANUFACTURE. 



117 



adulteration, there is no doubt that its use will become more 

 and more general, especially as it enables rubber to be secured 

 and shipped in a day or two. 



" Our illustration shows one of a number of mechanical block 

 rubber presses, which have recently been supplied to Messrs 

 The Mabira Rubber Company, Uganda, to the instructions of 

 Dr Christy, the makers being Messrs David Bridge & Co., of 

 Castleton, Manchester. A description of this press will not be 

 out of place, as it differs from any that have been previously 

 made. It consists of a 

 powerful screw fitted with 

 a machine-cut worm wheel, 

 driven by a steel-cut worm 

 by fast and loose pulleys. 

 A reversing motion is ar- 

 ranged for the quick with- 

 drawal of the platten. This 

 is carried on two strong 

 steel columns, bolted to the 

 base. The platten proper 

 has a detachable platten 

 cottered to it, on which are 

 letters for branding the 

 block rubber. The box is 

 detachable, therefore any 

 number of boxes can be 

 used with the one press. 

 Each box is fitted with 

 two strong wrought - iron 



bridles, with four powerful screws. After the crepe rubber 

 has left the vacuum drier, it is pressed in the box, and when 

 under pressure the bridles are brought over to an upright 

 position. The screws are then brought down on the top of the 

 false platten, the cotters of which are knocked out, leaving the 

 rubber under pressure, and the screws run back clear of the 

 box ; the latter is then removed and run on to the lower shelf 

 of the vacuum drier for a period of setting. When quite set, 

 it is again removed from the vacuum drier. The bottom of the 

 box, which is hinged, then allows the block to be forced out 

 by the four vertical screws. 



FIG. 22. Messrs David Bridge & Co.'s 

 Block Rubber Press. 



