Lot Essay
Christopher Pinchbeck b. 1710 d. 1783
Son of Christopher Pinchbeck b. 1670 d. 1732 who invented a zinc-copper alloy resembling gold and called "Pinchbeck". Christopher Junior was elected a member of the Smeaton Society (then known as the Society of Engineers) in 1774 and became vice-president in 1778 and president in 1781. He had been a member of the Royal Society of Arts since 1757 and was awarded a gold medal for the invention of his safety crane in 1767. This device had been prompted by a spate of accidents to the "wheel cranes" used in London Docks and operated by men in a large tread wheel. If the load fell from the hook the tread wheel spun out of control, often killing the occupants. Pinchbeck devised a mechanism for locking the crane using a latch moved by a pair of bellows, having an exhaust sufficient in size to allow the passage of air at normal operating speeds, but using excess air to close the locking mechanism if the speed of the bellows rapidly increased. It was this invention which earned Pinchbeck the Royal Society's Gold medal in 1767 after trials had been completed to show that the idea worked.
Despite this success, there is no record of the device being used. Also, as Pinchbeck chose not to patent his idea, there is no patent record, but there is evidence from Society's records that the model was placed in their repository. It was probably included in Christie's sale of Pinchbeck property Jan 1784.
Sources
1. Christie's is most grateful to Susan Bennett, the Archivist at the Royal Society for the encouragement of Arts Manufacturers and Commerce (the RSA) for her help in researching this model.
2. Rita Shenton, Christopher Pinchbeck and his family.
Son of Christopher Pinchbeck b. 1670 d. 1732 who invented a zinc-copper alloy resembling gold and called "Pinchbeck". Christopher Junior was elected a member of the Smeaton Society (then known as the Society of Engineers) in 1774 and became vice-president in 1778 and president in 1781. He had been a member of the Royal Society of Arts since 1757 and was awarded a gold medal for the invention of his safety crane in 1767. This device had been prompted by a spate of accidents to the "wheel cranes" used in London Docks and operated by men in a large tread wheel. If the load fell from the hook the tread wheel spun out of control, often killing the occupants. Pinchbeck devised a mechanism for locking the crane using a latch moved by a pair of bellows, having an exhaust sufficient in size to allow the passage of air at normal operating speeds, but using excess air to close the locking mechanism if the speed of the bellows rapidly increased. It was this invention which earned Pinchbeck the Royal Society's Gold medal in 1767 after trials had been completed to show that the idea worked.
Despite this success, there is no record of the device being used. Also, as Pinchbeck chose not to patent his idea, there is no patent record, but there is evidence from Society's records that the model was placed in their repository. It was probably included in Christie's sale of Pinchbeck property Jan 1784.
Sources
1. Christie's is most grateful to Susan Bennett, the Archivist at the Royal Society for the encouragement of Arts Manufacturers and Commerce (the RSA) for her help in researching this model.
2. Rita Shenton, Christopher Pinchbeck and his family.