U.S. patent number 3,852,846 [Application Number 05/276,122] was granted by the patent office on 1974-12-10 for door hold open attachment for a door check.
This patent grant is currently assigned to Republic Industries, Inc.. Invention is credited to Loren E. Slaybaugh.
United States Patent |
3,852,846 |
Slaybaugh |
December 10, 1974 |
DOOR HOLD OPEN ATTACHMENT FOR A DOOR CHECK
Abstract
An attachment for a conventional, surface mounted, overhead door
control incorporating electrically actuated provision for holding
the door open to any desired degree, but defeatable by manual
pressure or by deenergization of the electric circuitry.
Inventors: |
Slaybaugh; Loren E. (Arlington
Heights, IL) |
Assignee: |
Republic Industries, Inc.
(Chicago, IL)
|
Family
ID: |
23055273 |
Appl.
No.: |
05/276,122 |
Filed: |
July 28, 1972 |
Current U.S.
Class: |
16/48.5; 16/51;
16/62; 251/129.03 |
Current CPC
Class: |
E05F
3/223 (20130101); E05Y 2900/132 (20130101); E05F
3/102 (20130101); E05Y 2201/20 (20130101); Y10T
16/276 (20150115); Y10T 16/22 (20150115); E05Y
2201/254 (20130101); Y10T 16/2804 (20150115) |
Current International
Class: |
E05F
3/00 (20060101); E05F 3/22 (20060101); E05f
015/20 () |
Field of
Search: |
;16/48.5,49,51,52,55,62
;251/141,138,140 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Frazier; Roy D.
Assistant Examiner: Aschenbrenner; Peter A.
Claims
I claim:
1. In a door check of the type which includes means defining a
cylinder, a member slidable within said cylinder, resilient means
biasing said member toward one end of said cylinder, means for
connecting said door check to a door and frame combination to move
said member relative to said cylinder against said biasing means
upon opening said door, hydraulic fluid in said cylinder and means
for permitting fluid flow counter to the movement of said member to
restrain the movement of said door; a door hold-open mechanism
comprising means providing an extension of said cylinder on that
end thereof toward which said member is biased, a piston
resiliently biased within said extension to follow said member and
having a one way flow passage therein to admit fluid therethrough
upon following movement against said resilient means, means closing
said extension, said closing means including a passage having a
valve seat therein for delivering fluid from the downstream side of
said one way flow passage to the upstream side thereof, a valve for
closing against said valve seat, and electrically actuated means
for operating said valve.
2. The combination of claim 1 wherein said valve closes against
said seat from the downstream side thereof.
3. The combination of claim 1 wherein said valve is energized with
sufficient force to close against the pressure imposed by said
resilient means but insufficient force to hold against a pressure
in excess of that of said resilient means.
4. The combination of claim 2 wherein said valve is energized with
sufficient force to close against the pressure imposed by said
resilient means but insufficient force to hold against a pressure
in excess of that of said resilient means.
5. The combination of claim 1 wherein said resilient means
establishes a pressure on the fluid between said piston and said
closing means, said valve has a face larger than said seat and said
fluid delivery passage includes a valve chamber on the downstream
side of said valve seat containing closely said valve, and said
electrically actuated means is adapted to urge said valve against
said seat with a force greater than the product of the pressure of
said resilient means and the area of said valve seat and less than
the product of the pressure of said resilient means and said valve
face.
6. The combination of claim 1 wherein said valve is an elongated
assembly having a face adapted to close on said seat and including
additionally a thimble mounted in fluid-tight relationship to said
cylinder defining means and containing the end of said valve
assembly remote from said face, and magnetic valve operating means
on the exterior of said thimble.
7. The combination of claim 1 wherein said fluid delivery passage
includes a tube mounted in said closing means and extending through
said piston throughout the range of movement thereof.
8. A combined door check and door hold open device including
resilient means for urging
a door toward closure upon expansion thereof, means defining a
hydraulic cylinder, a piston therein connected to move toward
one end of said cylinder with the expansion of said resilient
means, said resilient means establishing a pressure per unit
area on fluid ahead of said piston, means associated with said one
end of said cylinder defining a passage for the escape of fluid
from said one end having a valve seat therein, a valve adapted to
close against said valve seat from the downstream
side thereof, said valve having a face larger than said valve seat,
a valve chamber downstream of said seat, a portion of said valve
downstream of said face closely contained in said chamber to
substantially prevent fluid flow past said valve
and allow a pressure drop across said valve when said valve is
open, means providing a fluid escape passage opening into said
valve chamber upstream of said valve face at an open position of
said valve, means providing a fluid escape passage from said valve
chamber behind said closely contained portion of said valve when in
said open position, and means adapted to hold said valve
resiliently against said seat with a force in excess of the product
of said pressure and said valve seat area and less than the product
of said pressure and said face area.
9. The combination of claim 8 wherein said means for resiliently
holding said valve are electrically operated.
Description
SUMMARY OF THE INVENTION
In application Ser. No. 105,331, filed Jan. 11, 1971, of Paul W.
Martin for a "COMBINED DOOR CHECKING AND DOOR HOLD OPEN MECHANISM,"
there is shown a surface mounted door check unit of the type
wherein arcuate movement of an arm rotates a pinion meshed with a
rack carried by a piston. Rack movement compresses a spring upon
door opening, and the return thrust of the spring closes the door.
The closing movement of the door is restrained by the presence of
hydraulic fluid ahead of the piston in its closing direction of
travel which must escape through a metered orifice and return to
the back side of the piston. The inventive feature of that
application was the introduction of an electrically controlled
valve in the escape passage of the hydraulic fluid which, when
energized, blocked the passage and thus effectively prevented the
further travel of the piston in the closing direction.
In surface mounted door closers of the type shown in the Martin
application, it is conventional to provide two ports in the
cylinder wall in the direction of travel of the piston in the
closing direction and one port in the opening direction for the
metered restraint on the piston, to or past which the piston must
move. For the Martin device to operate effectively, the piston must
make a fluid tight seal with the wall of the cylinder, thus
demanding ring seals. As the sealing rings come to or pass the open
ports, they necessarily will bulge into the ports, and as they
return to the continuous wall portion, they stand a good chance of
being scuffed or nibbled off. The sealing is not essential in the
absence of the door hold-open provision of the Martin application,
or in the other words, where the closer is to function simply as a
door check, but it is needed where a fluid must be positively held
ahead of the piston.
The device of the present invention contemplates a displacement of
the door holding mechanism entirely away from the area of the fluid
escape ports such that no sealing of the rack piston is necessary,
and the movable member of the holding mechanism is not called on to
pass any ports.
The device of the present invention contemplates a wholly enclosed
valve operating armature such that no packing gland and no
possibility of oil drip occurs at the site of the door holding
valve.
The device of the present invention can be employed strictly as an
accessory or an attachment to a standard door closer such that the
standard closer may be modified simply by substituting the door
holding mechanism for the conventional end plug with no further
modification necessary. The door holding mechanism constitutes an
axial extension of the door check and lies wholly within the
longitudinal projection of the walls of the door check such that no
mounting change need be made in the check upon incorporation of the
door holding mechanism, and paneling or fairing may be employed to
provide a surface continuous with that of the check proper.
Finally, the device of the Martin application shows a door
hold-open mechanism which can be overpowered by manual pressure on
the door wherein the door will stand open at the point where the
overpowering force is released. The device of the present invention
contemplates an optional structure where, upon the application of
overpowering pressure even momentarily, the detention of the door
is released and the door swings to closure.
Other objects and features of this invention will be apparent from
the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a horizontal section through a representative door check
incorporating the device of the present invention, shown in its
condition when the door it controls is fully open;
FIG. 2 is a similar section shown with the parts thereof in the
door-closed position;
FIG. 3 is a fragmentary vertical section through the central
portion of the check taken substantially along the line 3--3 of
FIG. 1 looking in the direction of the arrows shown, however,
without the device of the present invention;
FIG. 4 is a transverse section through the cylinder or housing
taken along the line 4--4 of FIG. 1 looking in the direction of the
arrows;
FIG. 5 is a vertical section through an optional form of manifold;
and
FIG. 6 is a horizontal section through the manifold of FIG. 5 taken
along the line 6--6 of FIG. 5 looking in the direction of the
arrows.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The left hand portion of FIG. 1 illustrates a conventional door
check 10 of the surface mounted type. The door check (FIG. 3) may
be mounted by screws 11 to a wall 13 immediately above a doorway
with the operating end 12 of a pinion shaft 14 extending downward
from the door check housing 15. An appropriate arm linkage 17 will
be clamped at one end to the operating end 12 of the shaft 14 and
slidably engaged at its other end in a track 19 secured by screws
21 to the door 23 such that as the door is opened, the pinion shaft
14 will be rotated in one direction and as the door closes, it will
be rotated back to the starting position. Such interconnection
between the door check and the door is entirely conventional.
The housing 15 is internally longitudinally bored to define a
cylinder 16. The pinion shaft 14 spans the cylinder 16 and is
mounted in appropriate pinion bearings 18 with appropriate seals on
opposite sides of the cylinder. The pinion shaft has an integral
pinion 20 formed thereon within the cylinder 16. The pinion 20
engages a rack piston 22 within the cylinder. The rack piston may
best be regarded as an elongated cylindrical member having a long
transverse aperture 24 formed therein to leave cylindrical ends or
heads 26 and 28 connected by opposite, longitudinally extending
webs 30 and 32. The inside surface of web 32 has teeth formed
thereon to define the rack 34 with which the pinion 20 engages.
The left end of the cylinder 16 as seen in FIGS. 1 and 2 is closed
by a plug 36 secured within the open end of the cylinder in
fluid-tight relationship, and a door-closing, strong, compression
spring 38 is contained between the plug 36 and the left hand head
26 of the rack piston 22. When the door is closed, the relation of
the rack piston and spring is as illustrated in FIG. 2. Upon
opening the door, the pinion is rotated in a clockwise direction,
thus advancing the rack piston 22 to the left and compressing the
spring 38 (FIG. 1). When the door is released, the pressure of the
spring on the rack piston moves the piston to the right thus
rotating the pinion in a counterclockwise direction and through the
linkage with the door, draws the door shut.
The rack piston has one way, axial, fluid flow passages 40 and 42
through the heads 26 and 28, respectively, controlled by ball check
valves 44 and 45 to forbid fluid flow from the faces of the rack
piston heads into the central slot 24 but to permit flow from the
central slot out the ends of the piston.
As particularly illustrated in FIG. 3, the top wall 43 of the
housing is of augmented thickness to accommodate check flow
passages. On the left side of the pinion 20, there is a back check
system 48 which retards the movement of the door as it approaches
its full open position. It includes a bore 50 extending
perpendicularly through the wall 46 and opening into a shallow
recess or groove 52 formed in the interior wall of the cylinder 16.
A second perpendicular bore more remote from the pinion 20 likewise
extends through the wall 46 which is formed and tapped for the
reception of a needle valve 56. This bore opens into the cylinder
at the intended end of travel of the face of the cylindrical
portion 26 of the rack piston in the door opening direction. An
intersecting bore 58 interconnects the passage 50 and the needle
valve seat 54. The bores 50 and 58 are plugged at their outer ends
by plugs 60.
On the other side of the pinion 20 are the check passages operative
as the door closes. Nearest the pinion 20 is a bore 62 extending
through the wall 46 into the cylinder and opening into the recess
52 in the interior cylinder wall. The recess extends between and
includes the opening ports of bores 50 and 62. Bore 62 is conformed
and tapped for the reception of a rapid close needle valve 66. A
plain bore 68 extends through wall 46 to the right of needle valve
66 and is plugged 60 at its outer end. Still further to the right
is a bore 70 formed for the reception of a final, slow-close needle
valve 72. An interconnecting passage 74 is provided in through the
end 76 of the cylinder housing 15 to interconnect the bores 62, 68
and 70 and is plugged 60 at its outer end. Needle valve 66 is
adjusted to provide a relatively free flow of hydraulic fluid and
needle valve 72 to provide a highly restricted flow.
For ease of understanding, the check flow passages and the groove
52 have been shown in FIG. 3 as being situated on the vertical axis
of the cylinder 16, whereas, actually, the passages are offset from
the axis and the groove 52 is in the upper left quadrant of the
cylinder as shown in FIG. 4 so that the groove 52 avoids the
bearing structure 18 of the pinion shaft 14.
The housing 15 is provided at its righthand end with an internally
threaded plug seat 78, and when the door check is employed solely
as a door opening and closing rate controller, such a plug will be
emplaced. In the drawings here, the plug has been replaced by the
door hold-open mechanism to which this invention is primarily
directed, but it is believed important that the operation of the
door check itself by understood before embarking on a description
of the hold open mechanism. Accordingly, let a simple plug be
visualized as occupying the plug seat 78. The cylinder will be
filled with hydraulic fluid.
As the door moves from the illustrated open position of FIG. 1 to
the illustrated closed position of FIG. 2 under the force of the
closing spring 38, the rack piston 22 is forced to the right. At
the start, the face of the right hand head 28 is approximately
aligned with the rapid close needle valve port 62. As the face of
the cylinder advances, the ball check valve 5 closes, compelling
fliud flow through the ducts 62, 68, 70 and 74. Initial flow occurs
through both duct 70 and duct 68 into the connecting duct 74, is
restricted in exhaust by the needle valve 66 and bypasses the
cylinder head 28 through the groove 52 into the central cavity 24
of the piston whence it escapes through the ball check valve 44 in
the left hand piston head 26. This displacement continues until the
head 28 covers the duct 68 whereafter flow occurs only through the
tightly restricted needle valve 72. Movement thus continues at a
greatly reduced rate dictated by the needle valve 72 until the door
seats. It will be appreciated that although the spacing of ports 68
and 70 appears large, the geometry of the connecting arm is such
that this piston travel represents only the last few degrees of the
door swing.
In the opening direction, as the piston is moved to the left, the
ball check valve 44 in head 26 closes, compelling fluid flow past
the head and into the piston cavity 24 through the groove 52 until
the head 26 passes the end of the groove and fluid flow must
continue through needle valve 54, and ducts 58 and 50 to the groove
52. The restraint imposed here is to cushion the linkage as the
door approaches its fully open position.
In the present invention, a door hold assembly 80 is threaded into
the right hand end plug seat 78 instead of the imagined plug. The
door hold assembly 80 includes a tubular shell 82 externally
threaded at both its ends, one end being secured within the plug
seat 78 and the other end 84 having mounted thereto a tubular
solenoid shell 86, the solenoid shell being internally threaded to
cooperate with the external threads at the end 84. The shell 82
slidably contains a double walled, annular, cup-shaped, door hold
piston 88 having an axial through passage 90, an inner wall 92, a
base 94 confronting the rack piston 22 and an outer wall 96, all of
which define therewithin an annular cavity 98. The base 94 of the
piston has a bore 100 through the bottom thereof stepping to a
smaller diameter as at 102 which communicates with the annular
cavity 98. A check valve ball 104 is contained in the bore 100
between a ball check valve seat 106 press-fitted into the end of
the bore and retained by ball check valve seat retainer 108, and a
spring 110 biasing the check valve ball toward closure. The piston
is sealed against the inside wall of the shell 82 by a quad ring
seal 112 contained in an appropriate circumferential groove in the
outside surface of the piston adjacent its open end.
A cylindrical manifold 114 is contained within the outer end of the
shell 82. Its inside face 116 has an annular groove 118 and an
axial bore 120 extending only a short distance into the manifold.
The groove 118 has a sleeve 122 press-fitted into the outer
circumference thereof which extends deep into the annular cavity 98
in the door hold piston 88 when the piston is in its door closed
position as shown in FIG. 2, and barely emerges from the annular
cavity when the piston is in its extreme door open position as
shown in FIG. 1. The sleeve acts as a container and external guide
for a light follower spring 124 which is contained under
compression within and against the bottom of the annular cavity 98
of the piston and the annular groove 118 of the manifold. The
spring is light in comparison with the door closing spring 38 such
that it exerts no perceptible effect on the door closing operation
but ensures that the piston 88 will follow the rack piston 22 in
its movement. The diameter of the sleeve 122 is appreciably less
than the outside wall of the cavity 98 such that fluid may freely
pass between the sleeve and that wall.
The axial bore 120 has a fluid return sleeve 126 press-fitted into
it to extend into the axial passage 90 of the piston 88 in fluid
tight relationship. The seal is effected by a quad ring seal 128
contained in an enlargement 130 of the passage 90 at its end remote
from the rack piston and secured therein by a backup 132. The
length of the sleeve 126 is such as to maintain its fluid-tight
communicating relationship with the passage 90 throughout the range
of movement of the piston 88.
The manifold has three annular grooves in the cylindrical periphery
thereof, two of them 134, for sealing rings 136 and a central
manifold groove 138 serving as a departure point for forming
certain internal passages. Reverting for the moment to the inside
face 116 of the manifold, a blind hole 140 extends longitudinally
into the manifold from the spring seat groove 118. A radial
intersecting bore 142 is formed from the groove 138 through the
inside end of the bore 140 to the center of the manifold. The axial
fluid return bore 120 stops short of the position occupied by bore
142 so as to isolate these bores from each other. A passage 144
angles inwardly from the groove 138 to intersect the inside end of
the axial bore 120. A second passage 146 angles outwardly from the
groove 138 toward the center line of the manifold. Although
passages 144 and 146 are shown intersecting for reasons of clarity,
the groove 138 makes possible different points of entry of those
passages thereinto. Adjacent its outer face 148, the manifold has a
circumferential rib 150 thereabout.
The outer face 148 of the manifold has an annular groove 152
therein to receive a sealing ring 154, and inwardly of the groove,
an annular nipple 156. Centered in the nipple is an axial plunger
chamber 158 proportioned to accommodate loosely a plunger 160. The
plunger is a generally cylindrical body a little longer than the
chamber 158 with a tapering inner end 162 socketed to accommodate a
valve ball 164. Extending axially from the bottom of the plunger
chamber 158 is a bore 166 which intersects bore 142. The shoulder
168 at which bore 166 meets the floor of the plunger chamber 158
constitutes a seat for the ball 164.
A solenoid cap 170 consisting of a one piece, deeply drawn cup or
thimble with a flange 172 about its mouth is contained against the
outer face 148 of the manifold. The interior of the cup fits
closely on the nipple 156 of the manifold and the flange 172
thereof is of the same diameter as the flanged outer face of the
manifold. The interior of the solenoid shell 86 has a rib 174
thereabout, and as the solenoid shell is threaded on the outer end
of the piston shell 82, the rib 150 of the manifold and the flange
172 of the cup are caught between the end 176 of the solenoid shell
82 and the rib 174 to make, with the sealing rings 154 and 136, a
fluid-tight end for the assembly.
In the annular space between the wall 180 of the cup and the
outward extension 182 of the solenoid shell 80 is located a
solenoid winding 184, and an armature 186 is situated within the
cup in a position to be moved upon energization of the solenoid
winding. The solenoid winding is contained in position by an
annular solenoid cover 188 having a hole 190 therein for the
solenoid leads.
The operation of this device is as follows. Assuming that the door
is in closed position and the combined door check and door
hold-open mechanism is as shown in FIG. 2 and is to be moved to the
condition shown in FIG. 1, the rack piston 22 moves to the left as
described before, discharging fluid into the vacated space behind
it through the ball valve 44 in the piston head 28. The door hold
piston 88 will follow the rack piston in its movement under
influence of the spring 124, the ball check valve 104 yielding to
admit fluid therethrough into the annular cavity 98 and thence
around the loose fitting sleeve 122 into the space vacated by the
door hold piston 88.
Assuming now movement of the door from the open position to the
closed position or from the condition of FIG. 1 to that of FIG. 2,
the spring 38 expands moving the rack piston to the right which in
turn forces the door hold piston to the right before it against the
force of the spring 124. The ball check valve 104 closes and the
fluid contained to the right of the door hold piston is forced
around the spring retainer sleeve 122 into the space occupied by
the follower spring 124 and into the passages 140, 142, and 166 to
the solenoid valve seat 168. If the solenoid is deenergized, the
solenoid valve ball 164 is displaced from the seat by fluid
pressure, and fluid flow continues through passages 146 and 144 to
the fluid return sleeve 126, through the door hold piston, and to
the advancing face of the head 28 of the rack piston 22.
Thereafter, the fluid bypasses that head as described in
conjunction with the door check mechanism proper.
Energization of the solenoid 184 will cause the armature to bear on
the plunger 160 to hold the ball 164 against its seat and so
prevent the passage of the hydrualic fluid from the right side of
the door hold piston and thus maintain the door in an open
position. Even when the plunger is closed on the seat 168, it holds
the armature away from the center of the solenoid field, so
positive closing force exists. It will be appreciated that the door
need not be open to a fully open position for this retention to be
effective. If the solenoid 184 is energized, the door will hold at
any partially open degree to which it may have been moved.
The force with which the door is held open is measured by the
magnetic thrust of the armature 186 acting on the valve ball 164
against its seat. Desirably the solenoid will be so selected that
this force will be specifically limited. In other words, it is
desirable that the solenoid be capable of being manually
overpowered. When the necessary excess of pressure is applied to
the door to close it, the generation of excess pressure within the
chamber to the right of the door hold piston and within the space
occupied by the spring 124 and transmitted to the ball 164 through
the passages 140, 142 and 166 will lift the plunger 160 off its
seat and thus permit fluid flow past the valve in the fashion just
described to permit a manual closing of the door.
The above described advantages of this structure will be
appreciated from the description of the device thus far. The rack
piston 22 which operates in the area of the fluid escape ports by
which the rate of closure is governed has not and need not have
anything in the way of deformable sealing rings which might be
damaged by their passage to and through the ports. The door holding
structure which does demand such rings is wholly displaced from the
area of these ports and can operate within a continuous, smooth,
cylinder surface. Likewise, there is a total avoidance of any
exterior sealing of moving parts such as about the solenoid
controlled valve 160 through which leakage and drip might occur. It
will be noted that the valve plunger 160 and the armature 186 fit
relatively loosely within their associated containers. Hydraulic
fluid may and will leak past the valve member 160 and the armature
186 into the cup 170, but such presence of fluid is wholly
contained by static seals.
The door holding device is accessory in nature and may be
incorporated into an existing closure simply by removing an end
plug and substituting the device for it. The device lies within the
longitudinally projected walls of the door check proper and lends
itself to a masking by panels continuous with the side walls of the
door check such that the only visible decorative consequence of its
incorporation is an elongation of the unit.
In the device as just described, it will be appreciated that while
the solenoid controlled ball valve can be overpowered to permit a
forced closing of the door, once the application of overpowering
force is halted, the ball valve will reclose and further movement
of the door will stop. In the modification illustrated in FIGS. 5
and 6, a manual release valving arrangement is shown whereby, once
the valve is displaced from its seat by overpowering pressure, the
valve will hold open until the door goes fully closed. The manifold
200 is very similar in exterior contour to the manifold 114 of the
first described form. Thus, it possesses an annular groove 118 in
its inside face to receive the sleeve 122 and an axial blind bore
120 to receive the fluid return sleeve 126. On its cylindrical
periphery it has the two sealing grooves 134 the central
manifolding groove 138 and, at its outer face, the shoulder 150 to
be clamped between the end of piston shell 82 and the flange 172 of
the cup 170 by the solenoid shell 86. In its outer face, it has the
annular sealing groove 152 and the tubular nipple 156 in which the
plunger chamber 206 is formed. To this extent the two manifolds are
essentially identical.
The points of difference between this manifold and the first
described form lie essentially in the use of a different valve body
or plunger 202 and a differently situated exhaust port 204 from the
plunger chamber 206.
In this instance the plunger 202 mounts a valve check ball 208, as
before, at its tapered inner end 210 which diverges to a
cylindrical portion 212 which stands well clear of the walls of the
valve chamber 206 so as to permit a free flow of fluid therepast.
Outwardly of the portion 212 the plunger is necked down as at 214
and then expands again to a plunger head 216 which fits as closely
within the walls of the plunger chamber as conventional machining
practices conveniently permit and extends outwardly at this
diameter to the outer end which is engaged by the solenoid armature
186.
The admission of oil from the space back of the door hold piston 94
to the ball valve seat 218 is as described before. A bore 220
extends from the annular groove 118 to intersect a radial bore 222
extending from the manifold groove 138 through the center of the
manifold 200 which in turn is intersected by a small diameter bore
224 extending from the plunger chamber 206 to the radial bore 222.
The radial bore 222 is plugged outwardly of bore 220 as at 226.
These passages may be collectively referred to as the inlet passage
227 to the solenoid valve.
The exhaust passage 230, 230a differs from the first described
form. The immediate point of exhaust from the ball valve plunger
chamber, instead of being situated immediately adjacent the ball
valve seat 218, is displaced substantially outwardly of the ball
valve seat in reference to the axial length of the plunger chamber
as at bore 232 in the side wall thereof. This outward displacement
is such that when the ball 208 of the plunger 202 is seated against
the ball seat 218, the plunger head 216 will cover the exhaust port
232. A bore 234 extends parallel to the axis of the manifold 200,
intersecting the exhaust port 232 and going to a point radially
aligned with the manifold groove 138. A hole 236 extends radially
from the groove to intersect the bore 234. Thus a passage is
completed to the manifold groove 138 through 236, 234 and the
exhaust port 232. The bore 232 at its outer end forms only a groove
238 in the wall of the nipple 156, but the side wall 180 and flange
172 of the cup 170 enclose the groove to make a closed passage of
it.
At another point in the manifold groove 138, here shown to be
opposite, another bore 240 extends from the ring to the central
fluid return tube 126 to constitute the leg 230 of the fluid
exhaust passage, as in the principal described form.
Parenthetically, it should be noted that FIGS. 5 and 6 show two
planes through the manifold whereas FIGS. 1 and 2 show only a
single plane in order to make more clear the relationship of the
parts. Actually, the fluid inlet 140, 132, 166 and the two legs 146
and 144 of the fluid outlet need not all be situated in the same
plane as shown in FIGS. 1 and 2. Thus, the passage 144 of FIGS. 1
and 2 could occupy the same diametrically opposite position from
leg 146 as the passage 240 of the presently described form occupies
from the passage 236, communication occurring through the manifold
groove and the inlet passage 140, 142, 166, or be situated at right
angles to both of these. It is entirely a matter of convenience of
machining.
The operation of this alternative form of manifold is as follows.
Assuming the door hold-open piston is in the open door position as
illustrated in FIG. 1 with a quantity of fluid contained in the
cavity behind it communicating through the solenoid valve inlet
duct 227 to the valve seat 218, and the solenoid 184 is energized,
the door will be held open by virtue of the obstructed flow through
the valve seat 218. As manual pressure is now applied to the door
in the closing direction sufficient to overcome the thrust of the
solenoid armature 186, the ball is displaced from the seat 218 and
the pressure of the fluid as generated by the closing spring 38
will be applied against the entire face of the plunger including
the head 216. Since the force is now acting on a greatly increased
surface, the counter pressure exerted by the fluid against the
solenoid armature will be greatly augmented. The proportioning of
the solenoid thrust, the return spring pressure, and the whole face
surface of the plunger head 216 is such that the pressure of the
spring 38 acting on the plunger face is sufficient to continue the
overpowering of the solenoid armature thrust. Thus, the plunger
will move in the opening or displaced direction, i.e., to the
right, until the head 216 uncovers the exhaust port 232 to a
sufficient degree to permit the escape of fluid through the exhaust
system 230, 230a until the door has reached full closure. At this
point, the pressure on the plunger drops and the force of the
solenoid armature is again sufficient to restore the ball to
closure on the seat 218. In summary, therefore, with the solenoid
energized, as one opens the door, the movement is easy and the door
remains at the position to which it was opened. Upon the
application, then, of excess closing force to the door through just
enough arc to unseat the ball 208 from its seat 218, the door will
swing to closure without further application of force.
Since the plunger 202 fits the chamber 206 in near fluid-tight
relationship in this modification, means must be provided for
supplying fluid to or exhausting fluid from the outer end of the
plunger as contained in the cap 170. That part 242 of groove 238
outwardly of the plunger chamber exhaust port 232, walled in by the
cap 170 is in open communication with the interior of the cap,
connecting it to the zero pressure exhaust side of the solenoid
valve, so fluid is free to move back and forth. The armature in
this embodiment is loose within the cap as in the first described
form.
It is not essential that the plunger 202 be fluid-tight within the
chamber since the back side of the plunger is at zero pressure as
long as the fit is close enough to hold the leakage level well
below the input capacity of the inlet system to and through the
solenoid valve. Given the viscosity of the hydraulic fluid, this is
easily achieved by simple machining, and so again, sealing rings
are avoided.
* * * * *