Patent model with improvements on envelope-making machines

August 11, 1874

One of the most difficult problems encountered in the envelope manufacturing process was that of drying the gummed envelopes without interrupting the cycle. This patent model included an improved drying mechanism that turned envelopes as they were being taken from a drying chain and placed them against one another on the packing table to prevent the open flaps from catching on machinery and spoiling the stock. On August 11, 1874, Edwin Allen and David M. Lester were issued patent number 153920 for this device that delivered envelopes from an endless drying chain to a delivery table.