US2570937A

US2570937A - Valve for fluid-pressure systems

Info

Publication number: US2570937A
Application number: US77851A
Authority: US
Inventors: Gash Frederick
Original assignee: William Coulthard & Co Lt
Current assignee: William Coulthard & Co Lt; William Coulthard & Co Ltd
Priority date: 1948-02-11
Filing date: 1949-02-23
Publication date: 1951-10-09
Anticipated expiration: 1968-10-09

Description

Oct. 9, 1951 F. GASH VALVE FOR FLUID-PRESSURE SYSTEMS 2 Sheets-Sheet l Filed Feb. 23, 1949 id 1 Inventor, Eedet dc II. I B I Attorney Oct. 9, 1951 F. GASH I 2,570,937

VALVE FOR FLUID-PRESSURE SYSTEMS Filed Feb. 23, 1949 2 Sheets-Sheet 2 24 k /7 25 I rzvenlor;

A ttcrney 'm'etal into the diesa Patented Oct. 9, 1951 u vrso STATES PATENT OFFICE as'zonea VALVE FOR FLUID-PRESSURE SYSTEMS- Frederick-Gash, Carlisle,Engla;-nd-,; assignor to William Coulthard & Company -Limited,0arlisle, England, aBritish company Application February 23, 1949, Serial No, 77,851

In Great Britain February '11, I948" This-invention; is'for improvements in or relating. to valvemeans, The inventionis more particularly concerned. with valve means for controlling pressure fluid operated devices of the kind in which a. member (erg. a piston or plunger) is moved in at least" one direction by fluid pressure-and then makes a return stroke, during which-return stroke the pressure fluid is exhausted.- A particular application of the inventionis to: die-casting or moulding machines of the kind in which fluid pressure, generally through. a plunger or ram, forces the molten In such machines a device isi required which can-be adjusted and set so as automatically tocontrol the supply and exhausgovern the-amount of opening thereof.

According tofla further feature of the present invention there is provided a valve means comprising a valveblocle or casing having two cavities each adapted for connection to a pressure fluid system; twoone-way valve devices between said cavities, one valve device opening in one direction and the other in the opposite direction, fluid flowing through either of said valve devices acting to keep the other valve device closed, and an: independent adjustable setting device for each oisaid valve devices proper adapted to govern'the amount of opening thereof. Conveniently the valve devices properare ball valves and each. adjustable setting device is a screw, screw-threaded into the valve block andadapted to formiarstop to limit opening movement-f the ball valve;

lln applying the valve meansr just described to and valve.- readily? beset to: give the best operatingrcondiwhich thepressure fiuid flows to the cylinder. Similarly Whenrthe main control valve issubsequently operated; to exhaust the cylinder the speed: of return movement of the ram orplunger wh-ichmay be effected by pressure-fluid in a double-acting or-similar cylinder and plunger device-or byspring means orthe like)- depends on the-maximum permitted opening of the otherball The maximum permitted opening can tiohs-and this setting. maybe varied from job to -job One embodiment of the invention as-applied to a'valve means particularly suitable for application to a-pressure-fl-uid operated die-casting machine will now bedescribed by way of example with reference to the: accompanying semi-diagrammatic drawings. On-thedrawings:

Figure '1 is: a sideelevation of the complete machine, r

- Figure 2 is a sectional elevation of the com-- bined shooting cylinder and metal magazine, the sectionbeing-through the vertical axisof' the cylinder,

Figure 3' is a detail sectional View of thevalve,

Figure 4'is an end elevation of the valve; The general construction of the machine shown iii-Figure 1 follows existing practice and comprlses a frame It supporting a fixed die-carrier l l'and"guides 12 for a movable diecarrie'r Movement of the movable die-carrier is eflected by compressed air through a piston'and cylinder d'evi'ce Ill under the control of a handoperable valve": I5.

The-combined metal. magazine and shooting cylinder isin icated generally'at l6; see Figure '2; and comprises: "(see Figure 2) a cylinder proper 'l f' which works a piston 18 connected to and operating' the'sliooting ram [9", the latter shooting the'molten metal from the metal magazine 20 into the cavities of the mated die'sZl and 2 2 in-the usual way. Movement of the piston l8 andram I-Fin the fshooting direction iseffec'ted bycompres'sedair sup'pliedby a part-

flexible pipe

24, 24a, and acting on the underside 25 of the piston l8. Return movement of the piston and ram is effected by compressed air at constant pressure supplied by a part-flexible pipe 26 and acting on the annulus 21 of thepiston. The compressed air acting on this annulus is only capable of effecting return movement of the piston and ram when the pipe 24a is open to atmosphere. Control of the connection of pipe 24a to the source of compressed air, to efiect a shot hole. way valve and one ball valve opens in one direction and the other opens in the opposite direcspeed and return speed of the ram l9.

and to atmosphere for return movement of the shooting ram is provided by a hand-operable Valve 28.

The valve means provided for the purpose of the present invention is connected between the pipes 24 and 2421 as indicated at 39 in Figure 1.

The valve means comprises a rectangular valve block 48 opposite faces of which are bored or drilled to provide two cylindrical cavities 4| and 42 one towards one side of the block and one towards the other side. The open and screwthreaded end 43 of one cavity is adapted for connection by the pipe line 24 to the shooting cylinder IT. The open and screw-threaded end 44 of the other cavity is adapted for connection by the pipe 24a to the manual control valve 28. The cavitie 4i and 42 are connected together by two holes 45 and 46 which taper in opposite direc-, tions and each of which houses a

ball valve

41 and 48 respectively seated in the taper of the Thus each hole and ball constitutes a onetion. Each ball valve is provided with an independent adjusting and setting device by which 'the amount of opening of the valve can be preselected. -gland 49 screw-threaded into a wall of the valve Each adjusting device comprises a block 40 in axial alignment with the ball and its conical seating and an adjusting screw 50 screw- 'mum permitted opening of the ball valve can be selected and set to give the required shooting It will be appreciated that the separate adjusting devices provide for differential settings as between the one valve device 41 and the other 48. Preferably the balls are urged in' the closing direction by springs 52.

During the making of a shot the compressed air flows to the shooting cylinder I! from a supply pipe 24b (see Figure 1) via valve 28 (which is positioned so as to connect pipe 241) to pipe 24a) ,'pipe 24a, valve 45, 4! and pipe 24. The speed of the shot will, as stated, depend on the setting of the adjusting device 50 for the valve.41. On completion of a shot the valve 28 is operated to connect pipe 24a to atmosphere and close pipe 24b. The piston 18 then returns under the action of the compressed air supplied by pipe 26 and by exhausting the air below piston 18 via pipe 24,

valve

46, 48, pipe 24a, and valve 28.

The speed of the return movement of piston l8 'and ram I9 depends, of course, on the speed with which the air can be exhausted from the lower "part of the cylinder I! and, .as stated, this can be selected to give the return speed required,

by an appropriate setting of the adjusting device 50 for the valve 48.

It will be noted that when the air is flowing from opening 44 to opening 43, during the making of a shot it acts to close the valve 48 whereas when the air is flowing in the reverse direction it acts to close the valve 41.

Whilst the invention has been described more particularly as applied to die-casting machines it is of general application to pressure-fluid systems and apparatus. Furthermore, whilst the valve device, according to the invention, is particularly suitable for controlling the operation of the metal shooting plunger or ram of a diecasting or like machine it can also be used with advantage in some cases for controlling the opening and closing speed of the dies being connected, for example in a pipe extending between the cylinder [4 and valve [5 so as to constitute or form part of an anti-slam device for the dies.

I claim:

A two-way pressure fluid system comprising two conduits through which pressure fluid flows alternately from one ,to the other and valve means connecting said conduits together, said valve means including a rectangular shaped valve box having two short sides and two long sides, two relatively spaced cavities in said valve box parallel to each other and parallel with the short sides of said valve box, one of said cavities extending toward one long side of said valve box and the other of said cavities extending toward the other long side of said valve box and the outer end of each cavity having means for connecting it to one of said conduits, two oppositely tapered relatively spaced bores in said valve box between said cavities and communicating therewith, said bores being parallel to each other and parallel with the long sides of said valve box, a ball valve in each of said bores, said ball valves opening in opposite directions, a gland screw-threaded into each short wall of the valve box in axial alignment with a respective bore and the ball valve therein, an adjusting screw screw-threaded into the inner end of each of said glands so that its forward end is adjacent to and forms an adjustable stop for the ball valve to limit opening movement of the ball valve in the tapered bore, a reduced portion on the inner end of each gland, and a coil spring about each reduced portion and each adjusting screw and engaging each of said ball valves to urge each of said ball valves into closing position within its respective bore.

FREDERICK GASH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 479,309 Sewall July 19, 1892 726,841 Ball May 5, 1903 1,583,834 Humphrey May 11, 1926 1,923,127 Veenscheten Aug. 22, 1933 2,171,628 Lannert Sept. 5, 1939 2,207,681 Hibner July 9, 1940 2,210,555 Podolsky Aug. 6, 1940 2,271,031 Parker Jan. 27, 1942