US 2698517 A
Description (OCR text may contain errors)
2,698,51 7 -OPERATED Jan. 4, 1955 K. F. WITT AUTOMATIC MEANS TO CONTROL AND REVERSE FLUID CYLINDER-AND-PISTON UNITS 3 Sheets-Sheet 1 Filed May 21, 1952 Fig.2
INVENTOR. KENNETH F. W |TT. mam/FM ATT'Y.
K. F. WlTT Jan. 4, 1955 2,698,517 OPE.RATED AUTOMATIC MEANS TO CONTROL AND REVERSE FLUID CYLINDER-AND-PISTON UNITS 3 Sheets-Sheet 2 Filed May 21, 1952 QLW. 41% I ATTY K. F. WITT 2,698,517 AUTOMATIC MEANS T0 CONTROL AND REVERSE FLUID-OPERATED Jan. 4, 1955 CYLINDER-AND-PISTON UNITS 3 Sheets-Sheet 3 Y Filed May 21, 1952 JNVENTOR.
KENNETH F. WITT.
United States Patent AUTOMATIC MEANS TO CONTROL AND RE- VERSE FLUID-OPERATED CYLINDER-AND- PISTON UNITS Kenneth F. Witt, Winchendon, Mass.
Application May 21, 1952, Serial No. 289,042
1 Claim. (Cl. 60-97) This invention relates to fluid-operated cylinder-andpiston units and to the automatic control and reversal thereof.
It is the general object of the present invention to provide means controlled by the pressure in the active cylinder and effective to reverse the main valve at the completion of a piston stroke in either direction.
I also provide means to control the operation of two cylinder-and-piston units simultaneously, but with the pistons moving in opposite directions. A construction is also shown in which two controlled pistons operate successively and in the same direction.
My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claim.
A preferred form of the invention is shown in the drawings, in which Fig. 1 is a sectional plan view of certain fluid-operated mechanism involving my invention;
1Fig. 2 is a sectional elevation of my improved control va ve;
Fig. 3 is a fragmentary sectional elevation showing a slight modification to be described;
Fig. 4 is a plan view, partly in section, of a duplex mechanism, with the fluid-operated pistons moving simultaneously in opposite directions; and
Fig. 5 is a view similar to Fig. 4 but showing a pair of pistons arranged for successive operation in the same direction.
Referring particularly to Figs. 1 and 2, I have shown a power unit comprising a main cylinder C having a piston P slidable therein and connected to a piston rod R by which anv desired moving parts may be actuated. The head end of the cylinder C is connected by a passage and pipe 11 to a main valve V2, and the rod end of the cy inder C is simil rlv nnected by a passage 12 and pipe 14 to the same valve V2.
Fluid under pressure is supplied to the valve V2 through a pipe 15, and the valve V2 is provided with exhaust pass ve 16 and 17. A f ur-part iston or spool 20 is freely slidab e in the valve V2, and the valve is connected at its ends throu h pipes 21 and 22 t special control valves V3 and V4. A start-and-stop or shut-off valve V5 is supplied in the pipe 15, and a valve V6 in a by-pass 24 is provided for a purpose to be described.
The control valve V3 is shown in detail in Fig. 2 and is connected to the passage 10 in the cylinder C by a short pipe 26. The valve V4 is of identical c nstruction and is connected to the passage 12 by a pipe 27.
The valve V3 comprises a piston slidable in a cylinder 31 and normally held in the left-hand-position shown in Fig. 2 by a com ression s ring 32, which is interposed between a shoulder 33 of the piston 30 and a shoulder 34 at the inner end of an adiusting screw 35. The screw 35 is threaded in the cylinder 31 and may be gamed in or out to vary the compression of the spring The screw 35 has an axial recess 36 to loosely receive the piston rod 37, and the recess has a vent 38 to relieve the pressure therein. At its left-hand end, the piston 30 has an axial projection 39 which serves as a stop and ghicl'zt checks the piston 30 in the position shown in With the associated parts in the position shown in Fig. 1. fluid under ressure from the sup ly pipe 15 will flow through the pipe 14 and passage 12 to the righthand or rod end of the cylinder C will move the pis- ICC ton P to the left. The tension of the spring 32 in the valve V4 is sufiicient to prevent the piston 30 in said valve from being moved to the right so long as the piston P is free to move to the left in the cylinder C.
When the piston P reaches its limit of travel, however, as by engagement with the end of the cylinder, the fluid pressure will then build up in the right-hand end of the cylinder C and in the passage 12 and will eventually overcome the spring 32 and force the piston 30 to the right to uncover the pipe 22.
Strong pressure will then be applied through the pipe 22 to the main valve V2 and will shift the piston or spool 20 to its extreme left-hand position, thus reversing the main valve and the supply and exhaust connections of the main cylinder C and causing the main piston P to begin its travel to the right.
When the right-hand limit of travel is reached, pressure will build up in the left-hand end of the cylinder C and the valve V3 will thereupon be opened to supply pressure through the pipe 21 to again reverse the piston 20 and the main valve V2.
The piston P will thus be reciprocated between its defined limits of travel in both directions, and the direction of travel will be automatically reversed at the end of each stroke through the operation of the control valves V3 and V4 and without reliance on reversing dogs or other mechanical or electrical devices.
The only moving control parts are the pistons 30 in the valves V3 and V4, and these movements take place in one direction on the application of relatively heavy pressure through one of the pipes 26 or 27, and take place in the opposite direction as soon as the pressure in the associated pipe 26 or 27 is relieved. The entire operation is extremely reliable and satisfactory.
In Fig. 3, I have shown a needle valve interposed in a small passage 46 connecting the pipe 26a to the cylinder C. This needle valve may be adjusted as desired to control the speed of operation of the piston 30 in the associated valve V3 or V4.
The valve V6 in the bypass 24 may be opened manually to shift the main valve piston 20 to the left at any time and to thus apply pressure in the head end of the cylinder. If the valves V5 and V6 are both closed, all operations cease.
In the duplex construction shown in Fig. 4, two main cylinders C2 and C3 are provided. The cylinder C2 is connected by pipes 50 and 51 to a main valve V7 corresponding in all respects to the main valve V2 shown in Fig. 1. The right-hand or rod end of the cylinder C2 is connected to the main valve through a pressure-re- .sponsive control valve V8 which is identical with the valve V3 shown in Fig. 2. The valve V8 is connected to the cylinder C2 by a pipe 52 and is connected by a pipe 53 to a pipe 54 which connects the adjacent ends of the main valve V7 and a second main valve V9.
The cylinder C3 is connected by pipes and 61 to said main valve V9, which valve is of the same construction as the main valve V7 (Fig. 4) and the main valve V2 (Fig. 1). Fluid under pressure is supplied through a main supply pipe 63 and branch pipes 64 and 65.
A by-pass pipe 66 is connected into the left-hand end of the main valve V7 and is also connected through a cross pipe 67 to a pipe 68 which extends from a control valve V10 for the cylinder C3 to the right-hand end of the main valve V9.
the pipe 63 between the by-pass pipe 66 and the branch pipes 64 and 65.
In this duplex machine, the pistons 68 and 69 in the cylinders C2 and C3 are operated simultaneously but in opposite directions. Consequently, the piston of either cylinder may perform a working stroke while the piston of the opposite cylinder is performing a return stroke.
By momentarily opening the by-pass valve V11, the main valves V7 and V9 may be placed in the positions shown in Fig. 4. If the valve V12 is then opened, fluid under pressure will flow to the right-hand end of the cylinder C2 and to the left-hand end of the cylinder C3.
The piston 68 will then move to the left and the piston 69 to the right until the pistons reach the ends of their Fatented Jan. 4, 1955 respective strokes, whereupon pressures will be built up in the control valve V8, and the slidable pistons in the main valves V7 and V9 will be shifted to the left and to the right respectively, to reverse the operating connections of the main cylinders C2 and C3.
It will be noted that the cross pipe 54 connects the adjacent ends of the valves V7 and V9, while the cross pipe 67 similarly connects the outside ends. Consequently, when the piston 68 completes its stroke to the left and pressure builds up in the right-hand end of the cylinder C2, the control valve V8 will operate to admit pressure to the pipes 53 and 54 and to thus shift the piston in the valve V7 to the left and the piston in the valve V9 to the right. The piston 68 will then begin a movement to the right and the piston 69 to the left, which movement will continue until pressure is built up in the right-hand end of the cylinder C3.
The valve V10 will then admit pressure to the pipes 68 and 67, thus again reversing the main valves V7 and V9, whereupon the described cycle of operations will start over.
The valve V11 may be manually opened at any time to place the main valves V7 and V9 in the positions shown, and the valve V12 may be closed at any time to stop all further operations of the duplex machine.
In the duplex construction shown in Fig. 5, two main cylinders C and C6 are provided. The cylinder C5 is connected by pipes 70 and 71 to a main valve V14 corresponding in all respects to the main valve V2 shown in Fig. 1. The cylinder C6 is similarly connected by pipes 72 and 73 to a main valve V15. Pressure-responsive valves V20 to V23 are provided at the opposite ends of the cylinders C5 and C6 as shown.
The valve V20 at the closed end of the cylinder C5 is connected by a pipe 80 to the right-hand end of the main valve V15. The valve V21 at the rod end of the cylinder C5 is connected by a pipe 81 to the left-hand end of the main valve V15. The valve V22 at the lefthand or closed end of the cylinder C6 is connected by a pipe 82 to the left-hand end of the main valve V14, and the valve V23 at the right-hand or rod end of the cylinder C6 is connected by a pipe 83 to the right-hand end of the main valve V14.
Fluid under pressure is furnished through a supply pipe 85 and branch pipes 86 and 87 to the intakes 88 .and 89 for the main valves V14 and V15 respectively.
The usual exhaust connections 90 are also provided for the valves V14 and V15. A shut-off valve V25 is provided in the supply pipe 85, and a setting valve V26 is provided in the pipe 70.
Assuming that the parts are in the position shown in Fig. 5, the operation is as follows:
Fluid under pressure will be supplied through the supply pipe 85, branch pipe 86, intake 88 and pipe 70 to the left-hand or closed end of the cylinder C5, thus forcing the piston P to the right. When the piston has completed its right-hand stroke, pressure will be built up in the left-hand or closed end of the cylinder C5, which pressure will eventually overcome the valve V20 and will admit fluid under pressure through pipe 80 to the right-hand end of the main valve V15.
This will move the valve piston to the left and will admit fluid under pressure through the branch pipe 87, intake 89 and pipe 72 to the left-hand or closed end of the cylinder C6, thus moving'the piston P2 to the right.
After this stroke is completed, pressure is built up to open the valve V22 and admit fluid under pressure through the pipe 82 to the left-hand end of the valve V14, thus forcing the valve piston to the right and admitting fluid under pressure through the pipe 71 to the right-hand or rod end of the cylinder C5 and thereupon shifting the piston P to the left.
When this stroke is completed, pressure will be built up in the rod end of the cylinder C5 to overcome the valve V21 and admit fluid under pressure through the pipe 81 to the left-hand end of the valve V15, thus moving the valve piston to the right and admitting fluid under pressure through the pipe 73 to the right-hand end of the cylinder C6, with resultant movement of the piston P2 to the left.
When this movement is completed, pressure will be built up to open the valve V23 and admit fluid under pressure through the pipe 83 to the right-hand end of the main valve V14, thus returning the valve piston to its original position. Both pistons P and P2 are then in their original or extreme left-hand positions, and the described cycle of operations will thereupon be repeated.
The setting valve V26 may be closed as soon as the piston P2 in the cylinder C6 completes its stroke to the left, thus holding both pistons P and P2 in their extreme left-hand or loading position for as long a period as may be desired. All operations may be stopped at any time by closing the shut-off valve V25.
I have thus provided improved automatic mechanism for controlling the movement and reversal of one or more cylinder-and-piston units entirely by cylinder pressures and without the use of dogs or other mechanical or electrical devices.
Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claim, but what I claim is:
In a fluid-operated mechanism, two cylinder-and-piston power units, a main valve for each power unit and having a cylinder with a reversing piston slidable therein, a pressure-responsive control valve for each end of each power-unit cylinder, and direct connections from each control valve of each power unit to one end of the main valve for the other power unit, whereby a substantial rise in pressure in either power-unit cylinder will act directly on the main valve for the other power-unit cylinder and will thereby shift said main valve and reverse said other power unit.
References Cited in the file of this patent UNITED STATES PATENTS 1,938,758 Ernst Dec. 12, 1933 1,952,690 Strom, Sr. Mar. 27, 1934 2,223,792 Muir Dec. 3, 1940 2,287,709 Ringman June 23, 1942 2,342,450 Campbell Feb. 22, 1944 2,617,257 Douglas Nov. 11, 1952