Novelty doors are an open-and-shut case
As a youngster I can remember approaching the automatic doors of certain buildings with one arm out, open palm facing forward using ’the force’ to slide the glass at my will.
We tend to take this facility for granted now, which of course by its nature should be unobtrusive. But in November 1907 The Engineer reported on the technology when it was still very much a novelty.
The sesame design self-opening door was the invention of Mr R Falkland Carey of Pemberton, Arber and Co, Gray’s Inn Passage, London.
’There have been many attempts to design such a door, but we believe that they were only partially successful,’ the article reads.
Indeed, without infrared sensing mechanisms all these early attempts – including the one in question – relied on the weight of the person passing through as a trigger, which brought inherent problems.
One of the most difficult troubles to overcome is slamming
’One of the most difficult troubles to overcome in the self-opening doors is slamming; the closing is easy enough, as the weight shutting the doors is always the same, being slightly in excess of the necessary power required.
’In opening, the case is very different; a small child may step on the mat whose weight is barely sufficient to open the doors, or two or three heavy persons may step on the platform simultaneously, in which case the extra power above that wanted to do the actual work would cause the doors to move at an undue speed and cause violent slamming unless some powerful anti-slamming check was introduced.’
Carey presented such an innovation, which consisted of an elaborate set-up of pistons, levers and rollers, notably with a double piston working in a cylinder, submerged in an oil-tight bath or tank.