1862 London Exhibition: Catalogue: Class 7.: Thomas William Cowan
1578. COWAN, THOMAS WILLIAM, Kent Iron Works, Greenwich.
Patent air compressed machine-hammer for general forging.
The engraving represents an AIR HAMMER of 8 cwt. without compression. These hammers can be regulated to the utmost nicety for giving a blow equal in weight to the fraction of an ounce, and increasing it to about 45 cwt. The following is a description of the way this is effected:—
In the first place the motion to the hammer is transmitted by the strap and cam through a lever, which is raised every revolution of the cam. For a very light blow the cock at the bottom, which is usually open, is at this moment shut, causing the air to be compressed at the bottom of the cylinder, at the downward stroke of the hammer; this blow can be regulated by partially opening the cock. When a blow is required equal to the weight of the hammer itself, all the cocks are open. When a heavier blow is required the air is compressed by regulating the upper cock, which communicates with several chambers.
These hammers are recommended for general smiths' work, as they are very easily managed by any boy. The hammer block can be suspended at any part of the stroke, and the speed may be regulated the same as steam hammers.
Small hammers in sets of twos and fours driven from one shaft, and having conical speed pulleys, are very useful where rapidity of workmanship is required, as they are capable of giving about 360 blows per minute.
Trunk hammers are made on this principle for drawing out steel, etc. ; also movable cylinder hammers for the same purpose.
All these hammers have very heavy anvil blocks, and the main frame being fixed on these blocks it is impossible for them to sink in the ground without the whole machine going together; hence there is no danger of breaking any of the parts.
None of these hammers require massive foundations.
There is no expense in having to keep up a boiler with high-pressure steam for these hammers, as they are driven by a strap from the usual main shafting, and there is very little foundation required. They are perfectly under the control of the hammer-man, and very soon pay for themselves. Price, from £65 upwards.
WINTON and COWAN'S PATENT HIGH AND LOW PRESSURE DOUBLE CYLINDER HAMMERS are recommended for large forgings. These hammers are made to any size required, the smaller ones having single frames, as the drawing above, and the larger ones, for iron manufactories, double frames, they being best adapted for manufacturing iron and steel.
These hammers effect a great saving in steam, as the steam which is used in raising the hammer, after it has done its work in the small cylinder, is allowed to enter the large cylinder, and give the blow. Price, from £100 upwards.