Patent GB-190014022-A (GB)
Title: Improvements in Pneumatic Power-hammers.
Inventor: MASSEY HAROLD FLETCHER
Filed: 1900-08-04
Granted: 1901-07-27
Abstract: 14,022. Massey, H. F. Aug. 4. Fluid-pressure hammers.-Relates to pneumaticpressure power-driven hammers, and consists in a method of and means for controlling the number and force of the blows delivered, and other uses of the hammer. Fig. 10 shows a sectional elevation of one form of the invention, and Fig. 11 a broken section through the cylinder. The tup is suitably connected to a piston h working in the hammer cylinder b, which is connected at each end with the pump cylinder a by means of passages, one of which m is seen in Fig. 11. The ends of the pump cylinder are also connected with each other by means of a passage p. In the pump cylinder a is reciprocated a trunk piston c by an eccentric g on the power shaft. If the passages connecting the ends of the pump cylinder with the ends of the hammer cylinder be open and the passage p be closed, the to-and-fro movements of the pump piston c will cause air to be alternately rarefied and compressed at each end of the pump cylinder, and thus the hammer piston h and the tup j will be caused to perform movements to-and-fro approximately opposite to those of the pump piston c But, if the passage p be fully opened, the hammer piston h will remain unmoved. Various means may be provided for controlling the flow of air through the passages, whereby the action of the hammer may be regulated. In the example shown, a rotary plug t, fitting in a liner y and capable of controlling simultaneously the passages m and p, is provided. The plug t is not only capable of restricting or of closing the passages m and p, but it is perforated and furnished with non-return valves v arranged so that, in one position of the plug, air can pass in one direction only, and in another position air can pass in the opposite direction only- When the non- return or back-pressure valves v are made to prevent air from passing from the upper end into the lower part of the pump cylinder, the successive strokes will all force air into the upper part of the hammer cylinder, so that the tup will be forced downwards in such manner as to hold any articles or material that may be under it fast on the anvil. In like manner, when air is prevented from passing into the upper end of the pump cylinder, the hammer is held away from the anvil. The plug valve t is adjusted by a rack-bar 8, Fig. 20, capable of being operated either by a hand-lever 10 or by a treadle 15, the lever 10 being adjustably connected with the treadle through the medium of a notched sector 13. In some cases the rack-bar 8 is connected directly to the lever 10, and single blows may be delivered by properly manipulating the handle ; but, in order to enable single blows to be given more easily, the 'releasing-gear shown in Fig. 20 may in other cases be employed. The rack-bar, in this, is made in two parts, extended by a spring, the upper one bearing a catch plate 36, whereby it may be prevented from rising, when the lever 10 is depressed, by a detent carried by a balanced lever 35. This lever has a striking-screw projecting into the path of the trunk of the hammer piston c, so that the upper part of the rack-bar is released, and the valves are actuated, precisely at the requisite moment to produce the blow. Holes 31 may be formed at the middle of the pump cylinder, to correct any surplus or deficiency of air, or valves 32, Fig. 19, may be provided for the same purpose.