US2984225A - Piston and cylinder apparatus - Google Patents

Description

y 1961 D. H. YOUNG 2,984,225

PISTON AND CYLINDER APPARATUS Filed Aug. 18, 1959 5 Sheets-Sheet 1 Inventor B fi/zn f M1 9 $5M ttorney;

May 16, 1961 D. H. YOUNG 2,984,225

' PISTON AND CYLINDER APPARATUS Filed Aug. 18, 1959 3 Sheets-Sheet 2 Inventor tlorneys y 1961 D. H. YOUNG 2,984,225

PISTON AND CYLINDER APPARATUS Filed Aug 1959 s Sheets-Sheet 5 li /G. 4.

I 34 A N T United States Patent PISTON AND CYLINDER APPARATUS David Horace Young, 54 St. Jamess Ave., Hampton Hill, England Filed Aug. 18, 1959, Ser. No. 834,473

Claims priority, application Great Britain Sept. 9, 1958 6 Claims. (Cl. 121-164) This invention relates to single-acting piston and cylinder apparatus wherein movement of the piston in one direction is effected by fluid pressure acting on one side of the piston and the invention is more concerned with improved valve means for releasing and restoring the fluid pressure acting on such side of the piston.

The improved single-acting piston and cylinder apparatus according to my invention comprises a cylinder having an inlet for pressure fluid and a separate outlet for such fluid, a piston movable in one direction by pressure fluid from said inlet acting on one side of the piston, means urging the piston in the opposite direction, a valve controlling fluid flow through said outlet and having a stem, spring means engaging the stem of the valve for snapping the valve to and from its closed position from and to its open position, an actuating rod engaged with the spring means for actuating such means, and one pair of co-operating abutments movable with the actuating rod and the piston and a second such pair of co-operating abutments such that when the piston has been moved in said one direction by the fluid pressure to a predetermined position, the actuating rod is moved in one direction by one pair of abutments so that the valve snaps to its open position and, when the piston has been moved in said other direction to a predetermined position, the actuating rod is moved in the other direction by the other pair of abutments so that the valve snaps to its closed position.

In the specification of my co-pending application for Letters Patent Serial No. 834,458, filed August 18, 1959, I have described and claimed fluid-pressure actuated control apparatus more particularly for dispensing lubricant or other substance at a con-trolled rate. piston and cylinder apparatus may advantageously be incorporated in such control apparatus and will now be described with reference to one form of dispensing apparatus which is illustrated in the accompanying drawings, in which:

Figure 1 is a central vertical sectional view of the apparatus;

Figure 2 is a partial view, similar to that of Figure 1, showing the pistons and other parts in a difierent working position;

Figure 3 is a top plan view of the apparatus;

Figure 4 is an enlarged sectional view of the valve means for regulating the flow of hydraulic fluid to the reservoir, and

Figure 5 is a view to an enlarged scale of the valve means controlling the escape of pressure fluid from the lower cylinder.

The apparatus shown in the drawings comprises two axially aligned cylinders 1, 2 separated by a transverse wall 3 provided with a through-hole which is axially aligned with the cylinders and through which extends a piston rod 4 having at its ends pistons 5, 6 which work in the cylinders 1, 2 respectively. The cylinder 1 beneath the piston 5 receives pressure fluid, e.g. steam, from an inlet 7 and the steam passes from the cylinder through a My improved passageway 8 controlled by valve means which are indi cated generally by the reference numeral 9.

The space in cylinder 1 above piston 5 contains hydraulic fluid and this space is adapted to he placed in communication with a reservoir 10 surrounding the cylinder 2 by pasageways 11 and 12: flow through such passageways is controlled by valve means indicated generally by the reference numeral 13. The space in cylinder 2 above piston 6 has an inlet 14 controlled by a nonreturn valve and an outlet 15 also controlled by a nonreturn valve.

The piston rod 4 has an axial bore extending upwardly from the lower end thereof and movable in this bore is a rod 16 having a collar 16 pinned to the upper end thereof. Integral and axially aligned with rod 16 is a valve stem 16" which has an integral, axially aligned valve 16 comprising an intermediate reduced portion providing a head 17 and an annular shoulder 17 which is adapted to seal with the upper end of a flanged sleeve 18 which is made for example of polytetrafluoroethylenc and which is retained in the base of cylinder 1 by means of a screwed retainer ring 19. In all positions of the valve stem the valve head 17 seals with the inner wall of sleeve 18. The valve 16' has extending from the lower end thereof an axial bore 20 communicating with a plurality of radial pasageways 21 and it will be seen from Figures 1 and 5 that, with the valve 16 in the raised position thereof shown in those figures pressure fluid entering the cylinder 1 will pass directly into outlet passageway 8 and thence to the steam trap 22 via pipe 23.

A helical spring 24 surrounding piston rod 4 urges piston 5 to its lowermost position and a passageway 25 containing a spring-pressed ball 26 in a part thereof of enlarged diameter extends between reservoir 16 and the space in cylinder 1 above piston 5. A substantially rectangular spring plate 27 secured at its ends to the base of cylinder 1 has two intermediately disposed longitudinally extending tongues having recessed ends which engage in an annular groove 28 in the valve stem 16" (see Figure 5) and this spring plate is adapted to snap the valve 16' from the lowered position shown in Figure 2 to the raised position shown in Figures 1 and 5 and vice versa. The spring 27 may advantageously be backed by a rectangular spring plate (not shown) secured at its ends to the base of cylinder 1 and engaging in the annular groove 29 on the rod 16, see Figure 5.

The action of the apparatus so far described is as follows. With the pistons 5, 6 in the uppermost position thereof shown in Figure 1 pressure fluid entering cylinder 1 via inlet 7 passes freely to exhaust through radial passageways 21, bore 20, passageway 8 and pipe 23 and the piston 5 and piston 6 are moved downwardly under the action of spring 24. On downward movement of the pistons the lubricant or other substance to be dispensed is drawn into cylinder 2 via inlet 14 from a suitable source (not shown) and the hydraulic fluid is drawn from reservoir 10 through conduit 25 into the space in cylinder 1 above piston 5. Downward movement of the pistons continues until the end wall of the axial bore in the piston rod 4 engages the upper end of rod 16. Further downward movement of the pistons causes spring 27 to snap past its dead centre position to the position shown in Figure 2 thereby causing valve shoulder 17' to move into engagement with its seat thus preventing escape of pressure fluid from cylinder 1. Pistons 5 and 6 then commence to move upwardly under the action of the pressure fluid, piston 5 forcing the hydraulic fluid through passageways 11 and 12 into reservoir 10, flow through passageway 25 being prevented by ball 26, and piston 6 forcing the substance to be dispensed through the outlet 15.

The rate at which the hydraulic fluid is forced into the reservoir 10 and thus the rate at which the substance is dispensed is controlled by the valve means 13 which comprises a sleeve 30 (see Figure 4) screwed into a socket on the wall 3 and internally threaded at its outer end and provided at its inner end with a taper bore 31 communicating with passageway 11. Housed within the taper bore 31 is a ball 32 and the position of the ball in the bore may be adjusted by means of a plug 33 screwed into sleeve 30 and having an actuating handle 34. When the handle 34 is rotated to move the plug 33 to the left more and more hydraulic fluid can pass the ball valve and flow through the radial passage 35 in sleeve 30 into passageway 12, and it will be understood that the rate at which the hydraulic fluid passes to the reservoir 10 and thus the rate at which the substance is dispensed can be very closely controlled by the setting of the screwed plug 33. The sleeve 30 has an annular recess 30' communicating with the radial passage 35.

The pistons in their ascent finally reach a position in which the annular lip 36 on piston engages collar 16" on the rod 16 and the rod is then raised so that the spring 27 snaps to the position thereof in which valve 16' is in its open position. The above cycle of operation is then repeated.

A pipe 37 (Figure 3) connecting passageway 12 with reservoir contains a sight glass 38 containing two spaced and axially aligned rods 39. In operative position of the apparatus the tube 37 extends vertically and the hydraulic fluid drips from the upper rod to the lower rod, thus enabling the rate at which the hydraulic fluid is forced into the reservoir 10, and thus the rate at which the substance is dispensed, to be readily judged.

The valve means 9 enable the direction of movement of the pistons to be very rapidly changed and it will be appreciated that the apparatus disclosed affords a simple means for closely regulating the rate at which a lubricant or other substance may be dispensed. Movement of the piston rod 4 may be utilized to control a wide variety of other operations, for example piston rod 4 may be so adapted that when it reaches predetermined positions in the cylinder 2 it opens and closes the blow-off valve of a steam boiler or eflects numerous other controlling operations in a manner which will be clear to those skilled in the art.

It will be appreciated that the release and restoration of the fiuid pressure acting on piston 5 is eflected by a simple valve mechanism that will function accurately and have a long life, and that the valve, valve stem and rod assembly 16, 16, 16" is positively guided at each end for all working positions thereof.

In the apparatus illustrated in the drawings the valve 16' with its stem 16" is axially aligned and integral with the actuating rod 16 for spring 27. The valve with its stern could, however, be separate from the actuating rod and secured to any other part of the spring to be snapped open and closed thereby.

I claim:

1. A single acting piston and cylinder apparatus comprising a cylinder having an inlet for pressure fluid and a separate outlet for such fluid, a piston movable in one direction by pressure fluid from said inlet acting on one side of the piston, means urging the piston in the op posite direction, a valve controlling fluid flow through said outlet and having a stem, spring means engaging the stem of the valve for snapping the valve to and from its closed position from and to its open position, an actuating rod engaged with the spring means for actuating such means, and one pair of co-operating abutments movable with the actuating rod and the piston and a second such pair of co-operating abutments such that, when the piston has been moved in said one direction by the fluid pressure to a predetermined position, the actuating rod is moved in one direction by one pair of abutments so that the valve snaps to its open position and, when the piston has been moved in said other direction to a predetermined position, the actuating rod is moved in the other direction by the other pair of abutments so that the valve snaps to its closed position.

2. Apparatus as claimed in claim 1, wherein the piston has a rod, the piston and rod assembly has a bore therein, and the end of the actuating rod remote from the spring means is movable in such bore.

3. Apparatus as claimed in claim 2, wherein the end wall of the bore and the end of the actuating rod remote from the spring means form one pair of co-operating abutments and a lateral abutment adjacent such end of the actuating rod and an inward projection on the piston form the other pair of co-operating abutments.

4. Apparatus as claimed in claim 1, wherein the valve and its stem are axially aligned with the actuating rod.

5. Apparatus as claimed in claim 4, wherein the valve comprises an intermediate reduced portion providing a head at the free end of the valve and a shoulder at the other end, the valve extends into a sleeve surrounding the pressure fluid outlet so that the head seals with the sleeve in the valve open and valve closed positions of the valve stem, the shoulder seals with the adjacent end of the sleeve in the valve closed position of the valve stem to prevent passage of pressure fluid through the sleeve to the outlet, and a passageway extends from the free end of the valve to the side wall of the reduced portion so that in the valve open position of the valve stem pressure fluid can pass through the passageway to the outlet.

6. Apparatus as claimed in claim 1, wherein a spring urges the piston in the opposite direction.

References Cited in the file of this patent UNITED STATES PATENTS 1,880,650 Zagst Oct. 4, 1932 2,057,364 Bystricky Oct. 13, 1936 2,060,180 Davis Nov. 10, 1936 2,258,493 Hull Oct. 7, 1941 2,406,747 Davis Sept. 3, 1946

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