Patent GB-362260-A (GB)
Title: Improvements in and relating to compressed air tools and the like
IPC: B25D9/16
Filed: 1931-02-27
Abstract: 362,260. Percussive tools. CARLOTTI, C., 2, Rue St. Marc, St. Servais-Namur, Belgium, and HAPREMA HAGENER PRESSLUFTAPPARATE UND MASCHINENFABRIK QUAMBUSCH & CO. KOM. GES., Hegen, Westphalia, Germany. Feb. 27, 1931, No. 6261. Convention date, Feb. 28, 1930. [Class 122 (ii).] The distribution of working-fluid in a percussive tool is controlled by a central reversible lift valve 21 of ball. plate, or piston form, and two hollow cylindrical slides 22, 23 upon which the valve 21 seat and effects the inlet, and cut-off. The stroke of the slides 22, 23 is less than that of the valve 21 and they are constantly urged to the central position by the fluid supply. The construction permits expansion working. Dual exhaust arrangements are provided. The air is supplied through a pair of passages 10, 11 which are forked into branches 12 .. 15 respectively. The supply valve 7 has two openings 35, 36 to engage the passages 10, 11. The opening 36 is elongated. The first movement of the valve 7 supplies fluid to passage 10 which results in a rear position of the power piston. Further movement of the valve 7 closes passage 10 and opens passage 11 through the port 36. The distributing-valves are moved to the left and the piston driven forward. Further movement of valve 7 opens both passages 10, 11. The construction ensures the starting of the tool irrespective of the positions taken up by the moving parts. The cylinder, Fig. 1, is provided with main, fluidpressure ports 16, 18, a piston-controlled main exhaust 20, and auxiliary exhaust passages 17, 19 controlled by the piston and the slides 22, 23. The valves 21, 22, 23 are housed in a casing arranged at the end of the cylinder. The valves have flanges which slide in auxiliary cylinders 26, 27 in the casing. The outer ends of these cylinders are connected to supply branches 13, 15; the inner ends are connected to the atmosphere. The flanges form actuating-areas and limit the valve movements. The flange 24 is slightly greater in area than the flange 25. The'valves 22, 23 have ports which register with the passages 16, 18, and grooves 30, 31 respectively which control auxiliary exhaust connections 33, 17, 32, 19. In the position shown in Fig. 1, when the piston 2 passes the port 20, the fall of pressure in the front end of the cylinder causes the plate 21 and valve 23 to move to the right until the plate 21 strikes the slide 22 which however is temporarily locked by the excess pressure on the flange 24. When the piston closes port 17, the cylinder compression moves the plate 21 and slide 22 to the right. The compression and pressure on flange 25 moves the valve 23 to the right until the flange 25 engages the bottom of the cylinder 27. Fluid is supplied to the rear end of the cylinder through the gap formed between the valves 23, 21. When the piston 2 passes port 20 in its forward movement, the release causes the valves 21, 22 to move to the left until the valve 23 is engaged when it is moved until the flange 24 engages the bottom of the cylinder 26. The cut-off is thus effected. When port 19 is passed, the compression moves the valves 21. 23 to the position shown. The flanges 24, 25 may be the same size, or formed as shoulders; the valve 7 may be adjusted by compressed air. In the construction shown in Fig. 4, the cylinder passages 16, 17 lead to the outer ends of the valve casing; valves 22, 23 are imperforate. The flanges 24, 25 are open on opposite sides respectively to fluid pressure and to the atmosphere ; grooves 30, 31 control the exhaust. Additional flanges 36, 37 are provided on the valves 22, 23 and slide in auxiliary cylinders which are connected at their outer ends respectively by cross passages 40, 41 to the main cylinder. The main exhaust passes by passages 17a, 19a and branches 42, 43. In the position shown in Fig. 4, when the piston 2 is moved and passes the passage 40, the valves 20, 21 move to the left until the valve 23 is engaged and the cut-off is effected. The fluid in the left-hand end of the cylinder expands. When the piston passes passage 41, cylinder fluid passes to the left of flange 31 but has no effect. When the piston closes passages 19a, 43, the compression acts on the slide 22 and plate 21. When the port 19a is opened, the pressure on the left-hand side of slide 23 and plate 21 is released, and the valves 21, 22, 23 move to the left. The flange 24 arrests the slide 22 permitting the supply of pressurefluid to the right-hand end of the cylinder. The passages 40, 41 may be arranged at different distances from the cylinder ends. The .passages 42, 43 may be dispensed with.