Note: Descriptions are shown in the official language in which they were submitted.
The present invention relates generally to means for
controlling fluid pressure operated mechanisms, and more parti-
cularly for controlling various sequential functions of linear
actuators, fluid pressure intensifiers, and other mechanisms
wherein the extent of movement of a member may be controllPd.
Further, this invention provides an improved reversing valve
arrangement for the controlling of fluid pressure operated
reciprocatory or oscillatory members, such as are used in pumps,
reciprocating motors and other related devices.
Summary of the Invention
The fluid pressure servo detent mechanism of this
invention involves wall structure including relatively stationary
and relatively movable wall portions cooperating to define an
expansible and contractable fluid chamber. One of said wall
portions has fluid inlet means for connection to a source of
fluid under relatively high pressure and fluid outlet means to
an area of relatively low pressure. One-way inlet and outlet
valves are provided for said inlet and outlet means respectively,
the inlet valve being arranged to be releasably held in a valve
closed condition by fluid pressure in said inlet means greater
than in said chamber, said outlet valve being arranged to be held
in a valve closed condition by fluid pressure in said chamber
greater than in said outlet means. Valve operating means in-
; cludes means interconnecting said valves for opening and closing
said inlet valve responsive to closing and opening respectively
of said outlet valve and simultaneously therewith. The valve
operating means further includes an actuator operatively coupled
- to said interconnecting means, said actuator being responsive to
predetermined movement of said movable wall portion in a chamber -~
expanding direction to open said outlet valve against pressure
of fluid in said chamber, and to close said inlet valve.
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Brief Description of the ~rawings
Figure 1 is a diagrammatic ~iew of a fluid pressure
system showing one embodiment of the servo detent mechanism of
this invention;
Figures 2 and 3 are views corresponding to a portion
of Figure l but showing different positions of some of the
parts;
Figure 4 is a view corresponding to Figure 2 but
showin~ a modified arrangement;
Figure 5 is an enlarged transverse section taken on
the line 5-5 of Figure 4;
Figure 6 is a view correspondin~ to Figure 2 but
showing another modification;
Figure 7 is a view corresponding to Figure 6 but
showing a different position of some of the parts;
Figure 8 is a view corresponding to Figure 3 but
showing still another modified form;
Figure 9 is a view corresponding generally to Figure 1
but showing a further modified arrangement; and
Figures lO and 11 are views corresponding to portions
of Figure 9, but showing different positions of some of the
parts, some parts being removed.
Detailed Description of the Embodiment of Figures 1-3
In Figures 1-3, wall structure is shown as comprising
a cylinder indicated generally at 12, and a piston 13 axially
slidable in the cylinder 12. The cylinder 12 includes a cylin-
drical wall 14, and opposite end walls 15 and 16, the piston 13,
cylindrical wall 14 and end wall 15 cooperating to define a fluid
chamber 17 that is expansible and contractable responsive to
axial movements of the piston 13 in opposite directions. A ~ ~
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piston rod 18 is secured to the piston 13 and extends axially
through a suitable opening in the end wall 16.
In Figure 1, inlet and outlet means to the chamber 17
comprises an inlet conduit 19 that extends from a fluid reservoir
20 to the end wall 15, and an outlet conduit 21 that extends from ~ ~
the end wall 15 to the reservoir 20~ A pump 22, pressure relief ~`
valve 23 and control valve 24 are interposed in the inlet conduit
19, for supplying fluid to the chamber 17 under relatively high
pressure, the outlet conduit 21 returning fluid to the reservoir
under relatively low pressure. The pressure relief valve 23 is
shown as being connected to the outlet or return conduit 21 by a
branch conduit 25, in the usual manner.
A one-way inlet valve provides communication between
the inlet conduit 19 and the chamber 17, the inlet valve com-
: prising a valve seat 26 and a ball valve element 27. A one-way
outlet valve is indicated generally at 28, the inner end of the
outlet conduit 21 being shown as providing a valve seat 29 for
: a movable plate-like valve element 30. The valve elements 27 and30 are interconnected by being attached to a lever 31 that is .
suitably connected at one end to the cylinder 12, as indicated -:~
. at 32, the inlet valve element 27 being connected to the lever
31 by a link 33. -~
... The arrangement of the valve elements 27 and 30 rela- :. :
tive to. each other, and the interconnection therebetween by
means of the lever 31 causes the inlet valve to be opened when
the outlet valve 28 is closed and vice versa, opening and closing
of either valve being simultaneous with closing and opening of
the other thereof. It will be noted that the outlet valve 30
is generally plate-like in form, to provide a substantially
~ 30 large surface area facing in a direction away from the valve
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seat 29 so that, when the outlet valve 28 is closed, fluid
pressure within the chamber 17, greater than that in the outlet
conduit 21, will hold the outlet valve element 30 seated
against the valve seat 29 and the inlet valve element 27 un-
seated from its valve seat 26. With the inlet valve open,
fluid under pressure from the pump 22 will cause the piston 13
and its piston rod 18 to be moved to the left with respect to
Figure 1. It may be assumed that the piston rod 18 may be con-
nected to any desired mechanism or element, not shown, to impart
movement thereto.
Means for operating the inlet and outlet valves com~
prises the piston 13, interconnecting lever 31, and an actuator
in the nature of a rigid link or rod 34 that extends in a dir-
ection longitudinally of the cylinder 12 and slidably through an
opening 35 in the piston 13. One end of the rod 34 is pivotally
connected to the lever 31, as at 36, the other end of the rod ~: :
34 including a head 37 to which is secured a coil compression
spring 38 that encompasses the adjacent end portion of the rod
34.
Assuming that the valve elements 27 and 30 are in their ::
positions of Figure 1, and that the pump 22 is energized and the
control valve 24 is open, fluid entering the chamber 17, under
pressure, will impart movement to the piston 13 toward the end
wall 16 of the cylinder 12. As shown in Figure 2, when the
piston 13 engages the spring 38, the spring 38 will become com-
pressed to a point where the pressure thereof against the head
- 37 will overcome the pressure of fluid in the chamber 17 against
the outlet valve element 30, causing the valve 28 to open and : ~.
the valve element 27 to engage its respective valve seat 26, as
shown in Figure 3. With the inlet valve closed and the outlet
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valve thus opened, the piston 13 with its piston rod 18 are
free to be moved toward the end wall 15 until the piston 13
engages the lever 31 to close the outlet valve 28 and reopen
the inlet valve. It will here be noted that tendency of the
piston 13 to move the lever 31 in a direction to close the
outlet valve 28 and move the inlet valve element 27 to an open
position during the greater part of movement of the piston 13
toward the end wall 15, due to frictional engagement of the
piston 13 with the rod 34, will be offset by pressure of fluid
within the inlet conduit 19 against the seated inlet valve element
27. The piston 13 and piston rod 18 may be moved toward the end
wall 15 by any suitable means, not shown. It will be appre-
ciated that, in some installations, it will not be necessary to
include the actuator spring 38. In such cases, the piston 13
directly engages the head 37 on the rod 34 to unseat the outlet
valve element 30 and move the inlet valve element 27 toward
seating engagement with its valve seat 26. In either case, such
movement of the valve elements 27 and 30 is aided by pressure of
fluid in the inlet conduit 19 against the inlet valve element 27.
Modification of Figures 4 and 5
In this modified arrangement, parts identical to those
shown in Figures 1-3 carry the same reference characters. In
Figures 4 and 5, a magnet 39 is shown diagrammatically, the same
being mounted in the outlet conduit 21 by suitable means, such
as by radial spokes 4~. The magnet 39 may be of the permanent
type, or an electromagnet, if desired. An outlet valve element
41 operates in the manner of the outlet valve element 30 and,
for the purpose of the present example, is shown as being pro-
vided with a magnetically responsive insert 42 which, when the
outlet valve element 42 is seated in its closed position, it is
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disposed within the magnetic field of the magnet 39. If desired,
the entire outlet valve element 41 may be of magnetically re~
sponsive material. Use of the magnet 39 and magnetically
responsive outlet valve element is advantageous in aiding
pressure within the chamber 17 in holding the outlet valve
in a closed condition when working with relatively light loads
and light fluid pressures. Under such conditions, the magnet
39 holds the valve element 41 in a closed position against its
valve seat at the beginning of an expanding cycle in the chamber
17 and against valve closing pressure of fluid in the inlet
conduit 19 against the inlet valve element 27, at least until
sufficient fluid pressure is generated in the chamber 17 to
hold the valve element 41 in a valve closed position.
Description of Modification of Figures ~ and 7
In this embodiment, an elongated rod 43 is substituted
for the rod 34, and has its inner end pivotally secured to the
lever 3I, as indicated at 44. The rod 43 has a screw threaded
outer end portion 45 that is screw threadedly received in an
elongated internally threaded sleeve 46 that slidably extends
through an opening 47 in the cylinder end wall 16. The threaded
end portion 45 is provided with a lock nut 48 that engages the
outer end of the sleeve 46. At its inner end, the sleeve 46 is
provided with a flange 4~ on which is mounted a tapered coil
spring 50 that encompasses the rod 43 and which has its smaller
diameter end engageable with the piston 13. As shown in Figure
7, the sleeve 46 is longitudinally adjustably movable on the
threaded portion 45, to vary the length of travel of the piston
13 before the lever 31 is operated to simultaneously close the
inlet valve and open the outlet valve. With this arrangement,
adjustment is quickly and easily made from the exterior of the -
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cylinder 12 in a very simple manner. By using a conical
variable rate spring, the same may be adjusted to cause opening
of the outlet valve 28 and closing of the inlet valve at closely
controlled positions of the piston 13 to a point where the spring
50 is totally compressed, as shown in Figure 7.
Modification of Figure 8
The structure illustrated in Fi~ure 8 differs from
that of ~igures 1-3 in its being provided with not only a magnet
of the type illustrated in Figure 4, but also manually operated
means for controlling the valves. In the arrangement illustrated
diagrammatically in Figure 8, a magnet 51 is disposed in the out-
let conduit in the same manner as the magnet 39, the outlet valve
element 52 containing magnetically responsive material. A
manually operated lever 53 is pivotally mounted at one end, as
indicated at 54, to a bracket 55 that extends longitudinally
outwardly from the cylinder end wall 15. Intermediate its ends,
the le~er 53 is pivotally connected, as indicated at 56, to one
end of a rigid link 57 that has its opposite end suitably con-
nected to the outlet valve element 52. This means provides a
manual override for the link 34 and spring 38, so that the
piston 13 may be stopped at any point in a forward movement
thereof, restarted or reversed in its direction of travel, as
desired.
; Modification of Figures 9-11
In the forms of the invention illustrated in Figures
1-8, the piston 13 is shown as being moved from the right to the
left by fluid pressure in the chamber 17, it being assumed that
the piston 13 is moved from the left to the right by any suitable
means, not shown. Figures 9-11 illustrate the use of the present
: 30 invention in producing a iluid pressure operated reciprocatory
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device wherein a piston is moved by fluid pressure alternately
in opposite directions. In Figure 9, a fluid pressure cylinder
58 is shown as comprising a cylindrical wall 59, opposite end
walls 60 and 61, these cooperating with a piston 62 to define : -
a pair of alternately expanding and contracting chambers 63 and ~ ~:
64. The piston 62 is provided with a piston rod 65 that extends ~-
through an opening 66 in the end wall 60. Although not shown,
it may be assumed that the piston rod may extend in opposite
directions from the piston 62 and through a suitable opening in
the end wall 61, if desired. Each end wall 60 and 61 is provided
with one of a pair of inlet conduits 67 that are connected to-
gether and to a fluid reservoir 68, there being a pump 69 and
control valve 70 interposed in the conduit 67. Further, each
end wall 60 and 61 is provided with a fluid outlet conduit 71,
these beiny connected together as a return line to the reservoir
68. As shown in Figure 9, a pressure relief valve 72 connects
the joined inlet conduit 67 intermediate the pump 69 and valve
70 to the joined outlet conduit 71.
Each of the inlet conduits 67 is provided with an inlet
. 20 valve 73 substantially identical to the inlet valve formed b~
: the valve seat 26 and valve element 27, and including an inlet
valve element 74. Further, each outlet conduit 71 is provided
within its respective chamber 63 and 64 with an outlet valve 75
similar to the outlet valve 28 and including an outlet valve :
element 76. Each inlet valve element 74 is connected to a lever
77 by a link 78, each lever 77 being pivotally mounted in the
cylinder 58, as indicated at 79, and each lever 77 intercon-
necting its respective inlet and outlet valve elements 74 and
76 in the manner of the lever 31.
Valve operating mechanism for the several valves 73
- and 75 includes a rigid link or rod 80 that extends slidably
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through an opening 81 through the piston 62 and which is con-
nected at its opposite ends to a different one of the levers 77.
The valve operating means further includes a pair of actuator
elements in the nature of coil compression springs 82 each con-
nected at one end to a different one of the levers 77 and inter-
posed therebetween and a respective side of the piston 62. In
Figure 9, each of the outlet valve elements 76 is shown as being
provided with a respective notched member 83 that is engaged by
a detent 84 to releasably hold its respective valve element 76
in a valve closed position.
As shown in Figures 9-11, the rod 80 is of a length
relative to the spacing between the levers 77 to cause one of
the inlet valves 73 to be closed while the other thereof is
open while respective outlet valves 75 are open and closed
respectively. As shown in Figures 9 and 10, the inlet valve
73 in the end wall 60 is opened while its respective outlet
valve 75 is closed, so that fluid pressure in the chamber 63
causes the piston 62 and piston rod 65 to be moved toward the
right with respect to Figures 9 and 10. As the piston 62
engages the righthand spring 82, the spring becomes compressed,
as shown in Figure 10, to a point wherein fluid pressure against
the lefthand outlet valve element 76 and action of its respective
detent 84 is overcome and the levers 77 swung to their positions
of Figure 11. As there shown, the lefthand inlet valve 73 be-
comes alosed, the lefthand outlet valve 75 is opened, the right-
hand inlet valve 73 being opened and the righthand outlet valve
being closed. With this action, fluid under pressuxe is
admitted to the chamber 64, and fluid in the chamber 63 is free
to return to the reservoir 68. As the piston 62 advances toward
the end wall 60, moving from the right to the left with respect
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to Figure 11, engagement of the lefthand spring a2 by the piston
62 and compression of that spring, will cause the levers 77 to
simultaneously move to their positions of Figures 9 and 10,
reversing the pressures in the chambers 63 and 64 and causing
movement to be imparted to the piston 62 in a righthand direction.
Thus, the piston 62 and piston rod 65 may be caused to recipro-
cate between the cylinder end walls 60 and 61, the speed of such
movement being controlled by suitable means, such as by the
control valve 70.
While we have shown and described several embodiments
of our fluid pressure servo detent mechanism, it will be under-
stood that the same is capable of further modification without
departure from the spirit and scope of the invention, as defined
in the claims.
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