US 3463188 A
Description (OCR text may contain errors)
I Aug. 26, 1969 R RYAN ET I 3,463,188
SHOT SPEED CONTROL VALVE AND METHOD OF CONTROLLING THE SPEED OF A SHOT CYLINDER RAM Filed Oct. 23. 1965 2 Sheets-Sheet 1 Z8 30 I 15 I6 84 INVENTOQS: 3 2, ROBERT A. RVm/ LEON/2 RD swim/5 6, 1969 R. R. RYAN ETAL 88 SHOT SPEED CONTROL VALVE AND METHOD OF CONTROLLING THE SPEED OF A SHOT CYLINDER RAM 2 Sheets-Sheet 2 Filed Oct. 23, 1965 ii 55* J MM EQM 9/ I 40 90 19.? Q
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N E M fi JL L 4 71 4 36 /04 j J26 l I [*fw 54 QQCUMULATOR gEsEm/ g Im/EMTORs: ROBERT E. RYHM LEO/V990 GJ'VERA/ER United States Patent 3,463,188 SHOT SPEED CONTROL VALVE AND METHOD OF CONTROLLING THE SPEED OF A SHOT "CYLINDER RAM Robert R. Ryan and Leonard G. Werner, St. Louis, Mo., assignors to St. Louis Diecasting Corporation, St. Louis, Mo., a corporation of Missouri Filed Oct. 23, 1965, Ser. No. 503,697 Int. Cl. F15b 7/08, 15/22 US. Cl. 137-599 3 Claims ABSTRACT OF THE DISCLOSURE A shot speed control valve including a casing having a reciprocatable spool piston therein, passages for supplying fluid under pressure to each end of the piston, passages for passing a maximum flow of fluid under pressure through said casing which is closed when said piston is in one limit position of movement and open a predetermined amount when said piston is in the other limit position of movement, means for adusting said other limit position of movement, an adustable by-pass channel for said maximum flow passages, an adustable metering passage for supplying fluid at one end of said piston at less then full flow for the initial travel of said piston, and adustable cushion means effective on the other end of said piston.
The present invention relates generally to controls, and more particularly to a novel shot speed control valve, an electro-hydraulic control unit or assembly, and a method for controlling the speed of a rams shot cylinder, and the like.
There has long existed the need for a means for and a method of controlling the stroke of the shot cylinder of a ram used in filling die cavities which will permit the initial proper evacuation of air from the die cavity, which will eliminate splashing of metal, yet which will fill the cavity at high speed. Many valves, structures and methods have been employed over the years within the knowledge of applicants who have been in the die casting business for many years. However, nothing heretofore available or known to them has achieved the initial adustable slow travel of the piston, the subsequent adustable high speed charging of the cavity of the die, and the subsequent slow speed return of the ram to starting position desirable in die casting.
Therefore, an object of the present invention is to provide a novel control device, unit, and method which fulfills the long existing need in the die casting art.
In brief, the present novel shot speed control valve includes a casing within which is disposed a reciprocatable spool piston. Means are provided for introducing fluid at each end of the piston, there being a volume control adjustment at the aft end thereof and an adjustable stop with cushioning device at the forward end. A main fluid line inlet and outlet into the casing are provided which are blocked by the spool piston in one position of the latter and are permitted free flow in another position thereof, with an infinitely adjustable restricted flow therebetween. A by-pass is provided around the piston associated with which is an adjustable volume control valve. There is also provided a by-pass for the fluid normally flowing through the adjustable volume control valve at the aft end of the piston. The novel valve is also part of a novel unit which includes operatively disposed in the fluid system for supplying fluid under pressure to the shot cylinder a four-way pilot valve, a four-way main valve, a reservoir, an accumulator and connecting lines.
Hence, another object is to provide a novel shot speed control valve and an electro-hydraulic control unit which 3,463,188 Patented Aug. 26, 1969 are constructed to control a rams shot cylinder, or the like, in a manner to insure a predetermined slow speed for a predetermined travel and a predetermined high speed for a further distance of travel in loading the die cavity with the molten metal.
Another object is to provide a novel shot speed control valve incorporating a piston and means for moving the piston slowly for a predetermined distance and thereafter moving the piston at a predetermine high speed for a predetermined distance in one direction.
Another object is to provide a novel shot speed control valve which incorporates means for supplying fluid under pressure to a rams shot cylinder, or the like, first, to move the latter at a selected slow speed for a predetermined distance, and thereafterwards to move the ram at a selected high speed in the filling of the die cavity.
Other objects are to provide a novel shot speed control valve which is of sturdy construction, which incorporates flow adjusting valves calibrated for ready adjustment, which is constructed for long service with minimum maintenance, thereby reducing down-time to a minimum, and which is otherwise constructed to fulfill the objects and advantages sought therefor.
Another object is to provide a novel method of controlling the speed of a rams shot cylinder to properly eliminate air and gases from the cavity of a die, to eliminate or materially reduce splashing, and to otherwise improve the character of castings by proper movement of the ram of the shot cylinder.
The foregoing and other objects and advantages are apparent from the following description taken with the accompanying drawings, in which:
FIGURE 1 is a side elevational view of a shot speed control valve constructed in accordance with the principles of the present invention;
FIGURE 2 is a horizontal cross-sectional view taken on substantially the line 22 of FIGURE 1;
FIGURE 3 is an end elevational view thereof looking from right to left in FIGURE 1, portions of the inlet and outlet pipe receiving wells being broken away for conservation of space;
FIGURE 4 is a vertical, longitudinal cross-sectional View taken on substantially the line 44 of FIGURE 2, portions of the adjustable volume control valves being omitted for clarity of illustration of other features;
FIGURE 5 is a vertical, transverse cross-sectional view taken on substantially the line 5--5 of FIGURE 4, the broken-away portions of the centrally disposed adjustable volume control being restored;
FIGURE 6 is a top plan view of the shot speed control valve; and
FIGURE 7 is a schematic layout illustrating the present novel electro-hydraulic control unit, of which the shot speed control valve is a part, used in conjunction with a shot cylinder, and forming a base for the present novel method.
Referring to the drawings more particularly by reference numerals, 10 indicates generally a shot speed control valve constructed to include the teachings of the present invention. The valve 10 includes a main body 12 having a cylindrical bore 14 therethrough within which is a spool piston 16 having a forward portion 18 and a rearward portion 20 connected by a stem 22. The main body 12 is closed at one end by an adjustable cushioned stop unit 24 and at the other end by a cover member 26, suitable bolts 28 maintaining the stop unit and cover member 24 and 26, respectively, securely in position. O-rings 30 insure tightly sealed relation between cover members 24 and 26 and the ends of the main body 12.
The main body 12 also includes integral, annular aligned wells 32 and 3-4 in which pipe elements 36 and 38 are secured by suitable welding 40, or the like for conducting fluid of the main line through the control valve 10 through aligned openings 42 when not blocked by the forward portion 18 of the spool piston 16.
A fluid by-pass 44 is provided for conducting a predetermined amount of fluid around the spool piston 16, particularly the forward portion 18 thereof, which includes vertical passages 46 and 48 and a connecting passage 50 (FIGS. 3, 4 and An adjustable volume metering control valve 52 is threadedly mounted in a vertically extending boss 54 integral with the main body 12 and includes a valve portion 56 which extends downwardly into the passage 50. A calibrated knob 58 and a scale 59, the latter being mounted on the top of the boss 54, provide a ready and accurate means for determining the position of the valve portion 56 in relation to the passage 50 for metering fluid through the passage 50, as desired.
The adjustable cushioned stop unit 24 for presetting the fast travel of ram and the like comprises a casing 60 having an elongated annular portion 61 and a square mounting base portion 62 which abuts the main body 12 and receives said bolts 28. Threadedly mounted in a reduced diameter portion of thelannular portion 61 at the free end for longitudinal adjustment in respect thereto is a shaft segment 63. The shaft segment 63 has a central bore 64 at the inner end which is tapped by four radial passages 65 which are in communication with a tube 66. At its other end, a dial 67 is secured to the shaft segment 63 which cooperates with a calibrated post 68 mounted in an enlargement of the annular portion 61, as shown. A lock nut 69 maintains the shaft segment 63 in selected position. A suitable O-ring is provided.
The shaft segment 63- is adjustable from the closed position shown in the drawings to a position to the left in which the spool piston 16 delivers full main line flow between pipe elements 36 and 38. The dial 67 and post 68 are calibrated and marked to indicate the selected position of the shaft segment 63.
The end member 26 has two horizontal passages 71 and 73 which are connected by a passage 70. An adjustable volume metering control valve 72 is threadedly mounted in the end member 26 and includes a valve portion 74 which extends into the upper end of the passage 70 for determining the flow therethrough (FIGS. 1, 2 and 4). A calibrated knob 76 cooperates with a scale 78 mounted on the upper edge of the end member 26 for ready determination of the position of the valve portion 74 in respect to the passage 70.
The passage 71 leads into a passage 80 in the bottom of the main body 12, which, in turn, leads into a vertical passage 82 open at its upper end into the bore 14, a fluid line 84 being tapped into the bottom thereof (FIG. 4).
In FIGURE 7 there is a schematic layout illustrating the relationship of the shot speed control valve with the shot cylinder 90 of a ram 92, the metal charge receiving unit and mold 91 with which the ram 92 is operatively associated, a main line four-way valve 94, a four-way pilot valve 95 for said main line valve 94, a shot speed control four-way pilot valve 96, an electric timer 97 for said valve 96, an accumulator 98, a reservoir 100, and connecting fluid lines.
A cycle of operation is initiated by closing an electrical switch (not shown) which simultaneously energizes, one, the four-way pilot valve 95 controlling the main line fourway valve 94, two, the shot speed control four-way pilot valve 96, and, three, the timing device 97 operatively connected to the valve 96 (FIG. 7).
When the valve 95 is thus electrically activated, fluid in line 114 under pressure from the accumulator 98 is released to move the spool in the main line four-way valve 94 to a predetermined position, this spool actuating fluid leaving the valve 94 by line 112 and returning to the valve 95, and on to the reservoir 100 by line 115. It will be understood that the usual pump is provided between the reservoir 100 and the accumulator 98 for maintaining the desired fluid pressure in the present closed fluid system. Upon the spool moving to the said predetermined position, there is provided full main line pressure flow from the accumulator 98 to the valve 94 by line 108, through the valve 94, thence by line 104 to the rear of the piston of the shot cylinder 90. Fluid in front of the piston of the shot cylinder is forced out of the front end thereof to the shot speed control valve 10 by the line 38. Since the control valve 10 is closed, or in the position of the drawings, at this moment, fluid can flow only through the by-pass 44, thence, via the line 36 to the main line valve 94, where it is diverted by the line 110 to the reservoir 100. Since only a small amount of the fluid under pressure can pass through the by-pass 44, the initial movement of the ram piston is at a predetermined slow rate.
As stated, the shot speed control four-way pilot valve 96 is simultaneously actuated, and fluid under pressure from the accumulator 98 reaches the valve 96 via line 124, the spool in valve 96 being electrically actuated to a position to divert fluid under pressure via line 84 and passages 82, 80, 71, 70 and 73 to the rear of the main spool piston 16 to move the same to the left, as viewed in the drawings, at a predetermined rate until the right end or rearward portion 20 thereof clears the passage 82. Thereupon, a full flow of high pressure fluid enters the valve 10 in the chamber behind the portion 20 causing the spool piston 16 to accelerate to high speed immediately, thereby opening the main fluid line allowing the fluid to flow through the shot speed control valve 10 to the full extent permitted by the setting of the adjustable stop unit 24. Thereupon, the piston of the shot cylinder 90 moves at a predetermined fast rate to force a liquid metal charge into a mold, as indicated in FIGURE 7, or to effect some other desired objective.
At a predetermined time, the cycle of the shot speed control valve 10 is reversed, being controlled by the timer 97. The pilot valve 96 is electrically actuated by the timer 97, the spool thereof being moved to a position to divert fluid from line 84 to line 64 so that fluid under main line pressure enters the chamber of the valve 10 to the left of the spool piston 16 through the stop unit 24. The spool piston 16 is moved back to its position of the drawings, closing the opening between lines 36 and 38 and permitting flow only through the by-pass 44. Fluid returning to the valve 96 via the line 84 is conducted to the reservoir 100 by line 126. This action occurs before the die 91 opens, hence, the piston of the shot cylinder 90 is reverted back to slow speed. As the die 91 opens, the piston of the shot cylinder 90 moves forwardly to the end of its stroke, clearing the sprue bushing.
At this point in the cycle, the pilot valve is electrically actuated by controls not shown to move the spool of the main valve 94 to divert fluid from line 104 to line 36. A reverse pattern of fluid movement to that as described above is obtained and fluid in line 104 is moved back through the main valve 94 and to the reservoir via line 110. Since, at this moment, the spool piston 16 is back in closed position, fluid under main line pressure flows from the accumulator 98 via line 108, through the main line valve 94, then via 36 through the by-pass 44 of the shot speed control valve 10, then via the line 38 to the front of the piston 90 to move the same at a slow speed on its return travel. Upon the return of the piston of the shot cylinder 90 to initial position, the cycle is completed.
It is clear that the shot speed control valve 10 is highly effective for its intended purpose of controlling the movement of the ram 92 in either direction, thereby achieving the objects sought therefor. It is also manifest that there has been provided a novel method of ram control. It is to be understood that the present novel control valve, control unit and method of control are adapted for other purposes and uses.
It is to be understood that the foregoing description and the accompanying drawings have been given by way of illustration and example. It is also to be understood that changes in form of the several parts, substitution of equivalent elements or steps, and rearrangement of parts or steps, which Will be readily apparent to one skilled in the art, are contemplated as within the scope of the present invention, which is limited only by the claims which follow.
What is claimed is:
1. In combination, a multi-use control valve for controlling a flow of fluid under pressure to actuate some device comprising a casing, a spool piston reciprocatable therein, means for passing a main flow of pressurized fluid through said casing, said means being closed in one limit position of said piston and predeterminately opened in the other limit position of said piston, a by-pass line for a portion of the main flow of fluid, adjustable metering means for controlling the flow through said by-pass line, means for introducing fluid into said casing against one end of said piston to move it in one direction, means for introducing fluid into said casing against the other end of said piston to move it in the other direction, means for metering fluid introduced against said one end of said piston, and means for by-passing said metering means elfective upon movement of said piston a predetermined distance in said one direction to increase the speed of movement in said one direction, said by-passing means being effective for continuous movement of said piston to its other limit position at the increased speed.
2. The combination of claim 1 in which said other limit position of said piston is adjustable from closed to fully open fluid flow.
3. The combination of claim 1 in which said second mentioned metering means is adjustable and calibrated for ready operation.
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3,012,751 12/1961 Hauser 251-285 X 3,159,378 12/1964 Haag 251-63 X 3,269,416 8/1966 Adams --L- 91-25 X 3,323,421 6/1967 Olmsted 25155 X ALAN COHAN, Primary Examiner US. Cl. X.R.