Note: Descriptions are shown in the official language in which they were submitted.
108106 Z J. M. BOWMAN - 1
Back~round of the Invention
The present invention relates to force multipliers and
more particularly to mechanical force multipliers.
The following description of the mechanical force
multiplier of the present invention i5 directed to its
employment in a diaphragm valve operator but may be employed
in connection with other apparatus in other environments
where mechanical force multiplication is required.
In a conventional diaphragm valve and air motor com- r
bination, a spring is required to exert its maximum force in
the valve closed position. However, since the spring can
only be compressed from the closed position, any movement
of the spring from that point can only result in additional
unnecessary force from the spring.
For example, a 3 inch weir diaphragm valve with 300 psi
(pounds per square inch) line pressure re~uires 5,300 pounds
of spring force to close the valve. Additional
force exerted by compressing the spring when the valve is
opened will result in 6,400 pounds of spring force, yet at
full open, only 1,600 pounds of force is required.
A conventional air motor utilizes a direct communication
between the diaphragm of the diaphragm valve and the spring
and air motor assemblies. This direct connection delivers !'
the same force to the valve diaphragm that is applied by the
spring and/or the air motor,
For example, a direct acting air motor is a fail open
operator. That is, if air pressure to the operator is ever
broken, then the valve will be opened. A spring is used to
maintain the open position or open the valve when air is
removed from the air motor. The air motor i5 used to close
.
- 2 -
~08~062 J. M. BOWMAN -- 1
the valve. The spring force and the force delivered from
the air motor in excess of the spring ~orce will act directly
on the valve diaphragm through the valve spindleO
A second example is a reverse acting air motor. This
is a fail close operator. If air pressure to the air motor
is ever broken, the valve will be closed. A sprin~ is used
to maintain the closed position or to close the valve when
air is removed from the air motor. The air motor is used to
open the valve. The spring force and any air motor force in
excess of the spring force is transmitted directly to the
valve diaphragm through the valve spindle.
Other valve operators have used linkage
arrangements or scissors mechanisms to actuate
valves. These devices use a primary link syatem with either
a handwheel or a small air motor reacting directly on the
primary link system. These devices are either limited in
stroke because angular movement is small, thus limiting the
stroke; or unable to accomplish full force multiplication to
benefit the air motor size. Also, these devices are not used
as fail safe actuators.
Summary of the Invention
An object of the present invention is to provide an
improved mechanical force multiplier.
Another object of the present invention is to provide
an improved mechanical force mul~iplier to operate a diaphragm
valve.
Still another object of the present invention is to
provide a lighter mechanical force multiplier for a diaphragm '
valve with a lower center of gravity then previously known
diaphragm valve operators.
-- 3 --
1~)8i~6~
A further object of the present invention is to provide a mechanical
force multiplier using a stacked link unit arrangement where a secondary or
second link unit is used to operate on a primary or first link unit.
A further object of the present invention is to provide a dia-
phragm valve operator with the force multiplier of the present invention
capable of being a reverse acting or direct acting operator providing full
valve stroke.
Another object of the present invention is to provide a force
multiplier in a diaphragm valve operator which is capable of closing or
opening a diaphragm valve with 300 psi of line pressure at 0% pressure drop.
Still another object of the present invention is to provide a
diaphragm valve operator enabling reduction of both spring size and air
motor size.
A further object of the present invention is to provide a mechanic-
al force multiplier and air motor actuator for a diaphragm valve which act
as a fail safe actuator.
According to the present invention, there is provided a mechanical `
force multiplier comprising: a first link unit having at least a first pair
of links, each of said first pair of links having one end thereof pivotably
coupled to and in a force transferring relationship with one of an actuator
and a device to be actuated and a second pair of links, each of said second
pair of links having one end thereof pivotably connected to a stationary
point and the other end thereof pivotably connected to the other end of an
associated one of said first pair of links; a second link unit having at
least a third pair of links, each of said third pair of links having one
end thereof pivotably connected to said other end of an associated one of
said first and second pair of links and the other end thereof pivotably
coupled to and in a force transferring relationship with the other of said
actuator and said device to be actuated; and at least one spring in a force
transfer~ing relationship with at least one of said first and second link
units, said first, second and third pair of links defining a volume having
a longitudinal dimension perpendicular to said first, second and third pair
- :~lL0~ 062
of links and said spring is disposed outside o said volume with the force
thereof being directed perpendicular to said longitudinal dimension from
the outside of said volume toward the inside thereof; said first and second
link units being disposed between said actuator and said device to be
actuated, said first and second link units in cooperation with each other
and said spring provide a relatively linearly increasing multiplied output
force to said device to be actuated when said actuator is actuated.
In contrast to conventional air motor operators, the fo~ce
multiplier of the present invention does not transmit forces from the spring
and air motor directly to the diaphragm of the diaphragm valve. The
mechanical force multiplier of the present invention actually multiplies
input force from the springs and air motor before they are transmitted to
the diaphragm of the diaphragm valve, thus allowing reduction in spring size
and air motor size.
For example, a direct acting force multiplier and air motor
assembly of the present invention is a fail open operator. Springs are
used to open the valve and/or maintain the valve in an open position. The
air motor is used to close the valve.
A reverse acting force multiplier and air motor assembly in accord-
ance with the present invention is a fail close operator. Springs are usedto close the valve and/or maintain the valve in a closed position. The air
motor is used to open the valve. The air motor forces and spring forces
are transmitted on both direct and reverse acting force multipliers in the
following manner.
The spring acts through a set of linkages (known as primary links
or first link units~ which actually vary
lV81()6Z J. M. BOWMAN - 1
the output force from the spring from approximately 1 timeY
the spring output to approximately 5.67 times the spring
output force depending on the angle of the links ~orming
the first link unit. The spring is under minimum required
amount of compression at the position where the force
multiplying effect is the largest and the spring is under
the maximum required amount of compression at the position
where the force multiplying effect is the smallest. The
air motor forces are also transmitted through a set of
linkages (known as secondary links or second link unit)
which in turn transmit these forces through the primary , -
or first link unit. Because the air motor force uses the
force multiplying effect of both the primary and secondary
links, the air motor size can substantially be reduced.
The force multiplying effect of the secondary links is
the smallest when the force multiplying effect of the
primary links is the largest. The force multiplying
effect of the secondary links is the largest when the force
multiplying effect of the primary links is the smallest.
This stacked mechanical force multiplier arrangement
- effectively reduces the air motor size required.
Brief Description of the Drawing
Above-mentioned and other features and objects of
this invention will become more apparent by reference to
the following description -taken in conjunction with the
accompanying drawing, in which:
Figs. 1 and 2 are diagrams illustrating how the
applied spring force changes as the primary link angle
changes when a constant output force is required;
.
' .
.. . . .
1081062 J. M. BOWMAN -- 1
Fig. 3 is a chart illustrating how the spring force
required for a spring to close the diaphragm of the diaphragm
valve varies in the mechanical force multiplier in accordance
with the principles of the present invention;
Figs. 4 and 5 are force diagrams to enable deriving
equations (1) - (3) as set forth hereinbelow for a complete
linkage or actuator system in accordance with the principles
of the present invention;
Figs. 6A and 6B are diagrams comparing the prior art
valve operator unit with the valve operator unit of the
present invention; -
Fig. 7 is an overall diagrammatic view of a diaphragm
valve operator unit incorporating the mechanical force
multiplier in accordance with the principles of the present
invention taken along line 7-7 of Fig. 8;
Fig. 8 is a diagrammatic illustration of the overall
diaphragm valve actuator taken along line 8-8 of Fig. 7;
Fig. 9 is a diagrammatic illustration of one mechanical
force multiplier embodiment for a reverse acting diaphragm
valve actuator in accordance with the principles of the
present invention taken aLong line 9-9 of Fig. 10 with the
diaphragm valve in a closed position;
Fig. 10 is a diagrammatic illustration of the embodi-
ment of Fig. 9 taken along line 10-10 of Fig. 9;
Fig. 11 is a diagrammatic view of the mechanical force
multiplier of Fig. 9 taken along line 11-11 of Fig. 12 with
the diaphragm valve in a full open position;
1~81~6Z J. M. sowMAN - 1
Fig. 12 is a diagrammatic view of Fig. 11 taken along
line 12-12 of Fig. 11;
Fig. 13 is a diagrammatic view of a second embodiment
of the mechanical force multiplier for ~ direct acting
diaphragm valve actuator taken along line 13-13 of Fig. 14
with the diaphragm valve in a full open position;
Fig. 14 is a diagrammatic view of the mechanical force
multiplier of Fig. 13 taken along line 14-14 of Fig. 13;
Fig. 15 is a diagrammatic view of the mechanical force
multiplier of Fig. 13 taken along line 15-15 of Fig. 16
with the diaphragm valve in a fully closed position;
Fig. 16 is a diagrammatic view of Fig. 15 taken along
line 16-16 of Fig. 15;
Fig. 17 is a third embodiment of a mechanical force
multiplier for a direct acting diaphragm valve actuator
taken along line 17-17 of Fig. 18 with the diaphragm valve
in a full open position;
Fig. 18 is a diagrammatic view of the mechanical force
multiplier of Fig. 17 taken along line 18-18 of Fig. 17;
Fig. 19 is a diagrammatic view of the mechanical force
multiplier of Fig. 17 taken along line 19-19 of Fig. 20
with the diaphragm valve in a fully closed position;
Fig. 20 is a diagrammatic view of the mechanical force
multiplier of Fig. 19 taken along line 20-20 of Fig. 19;
Fig. 21 is a fourth embodiment of a mechanical force
multiplier for a direct acting diaphragm valve actuator
taken along line 21~21 of Fig. 22 with the diaphragm valve
in a fully closed position;
Fig. 22 is a diagrammatic view of the mechanical force
multiplier of Fig. 21 taken along line 22-22 of Fig. 21;
-- 8 --
I
:
~08106Z
J. M. BOWMI~N - 1
Fig. 23 is a diagrammatic view of the mechanical
force multiplier of Fig. 21 taken along line 23-23 of Fig.
24 with the diaphragm valve in a full open position;
and
Fig. 24 is a diagrammatic view of the mechanical
force multiplier of Fig. 23 taken along line 24-24 of
~ig. 23.
Descriptio of the Preferred Embodiment
Referring to Figs. l and 2 there is illustrated
therein how the applied spring force FS changes as the
primary link angle changes when a constant output source
FD is required. These Figures illustrate that the mechanical
force multiplier of the present invention changes from
1 to 5.65, depending on the angle of primary mechanical
force multiplier links. The spring force will be maximum
as illustrated in Fig. 1 where the force multiplication
is the smallest (FD = Fs); whereas, the spring at minimum
compression in Fig. 2 when the force multiplication is
the largest (FD = 5.67 Fs).
Referring to Fig. 3, there is illustrated therein
how the spring force required for a spring to close the
diaphragm of a diaphragm valve varies in the mechanical
force multiplier of the present invention. It should be
noted that the maximum required force is 1,857 pounds
and the minimum required force is 934 pounds. Due to
this force multiplying effect, it is posslble to use
smaller springs in the mechanical force multiplier of
the present invention, thus reducing the total spring
weight and cost.
_ 9 _
1~8106Z J. Mo BOWMAN - 1
~ eferring to Figs. 4 and 5, the following equatlons are
derived which are used to calculate force for a complete
diaphragm valve actuator system in accordance with the principles
of the present invention.
FD = 1/2 of Total Stem Thrust
FS = Force Required to Keep Primary Links in Equilibrium
FL = Force Required in Secondary Link to Keep Primary
Links in Equilibrium
FA = 1/2 of Total Air Motor Force Required to Keep
Primary Links in Equilibrium
FD
S TAN 9 (1)
L S (SIN t ~ - ~)) (2)
FA = F~ SIN ~ (3)
Equation (2) is obtained as follows:
15Definition. In a triangle with angles A, B, and
C and sides opposite a, b, and c,
respectively, then
a = b = c
3~ ~ SIN B SIN C
Applying these equations to the
20 triangle of Fig. 6
FS = FL
SIN (0 - ~) SIN (180 - ~)
therefore,
Referring to Figs. 6A and 6B, there is illustrated
therein a comparison of the prior art diaphragm valve operator '
as shown in Fig. 6A and the diaphragm valve operator of the
present invention as shown in Fig. 6B. Both the prior art
-- 10 --
~ O ~ ~ J. M. BOWMAN - 1
operator of Fig. 6A and the operator of the present invention
of Fig. 6B are reverse acting air motor assemblies for a 3"
weir diaphragm valve. It will be noted that the center of
gravity (C.G.) is lower in the operator of the present
invention as shown in Fig. 6B. The weight of the,prior art
operator of Fig. 6A is approximately 300 pounds as compared
to approximately 150 pounds for the operator of the present
invention as shown in Fig. 6B. Both of these air motor
assemblies develop enough force to close a 3" weir diaphragm
valve with 300 psi line pressure at 0% pressure drop. Thç
prior art arrangement of Fig. 6A employs a Model 32130
ITT Grinnell air motor while the present invention as shown
in Fig. 6B employs a Model 3350 ITT Grinnell air motor.
It will be appreciated that the prior art diaphragm valve
operator as shown in Fig. 6A is relatively heavy and the
center of gravity is rather far above the diaphragm valve.
As can be seen from Figs. 6A and 6B, the spring S of Fig. 6A
has been moved from the top of the air motor AM to a position
between the diaphragm valve and the air motor AM of Fig. 6B,
moving the center of gravity closer to the diaphragm valve.
In order to transmit the horizontal spring motion of springs
S of the present invention as shown in Fig. 6B into a vertical
spindle movement, a pair of stacked link units is used as
will be discussed hereinbelow with respect to the remaining
Figures.
The same reference characters will be employed for the
same components throughout the following description of the
various embodiments of the mechanical force multiplier of
the present inventionO
.
108106~ J. M. BOWMAN - 1
Referring to Figs. 7 and 8, there is illustrated therein
a diagrammatic view of an overall operator including an air
motor 16 and the mechanical force multiplier disposed between
air motor 16 and the controlled diaphragm valve 26. The
arrangement illustrated in Figs. 7 and 8 is a re~erse acting
mechanical force multiplier which is built around a yoke.
The yoke serves to support air motor 16, houses link units 1
and 2 and supports the stationary link pin 19. The yoke can
be made as shown in Fig. 8 by using two side yoke platss 15
bolted to a top and bottom yoke plate 18 and 17 or by casting
or ~orging the yoke as one piece9 The yoke is attached to
the bonnet 20 of the diaphragm valve housing using an adaptor
bushing nut 21 and is attached to the air motor 16 in a
similar manner. However, any other form of attachment of
the yoke to the diaphragm valve bonnet and the air motor is
possible, such as bolting or casting the yoke as an integral part
o~ the bonnet and/or the lower air motor cover. The same
yoke can be made to accommodate direct acting mechanical
force multipliers also. Slots 27 in the yoke plate 15 are
for valve spindle position indicators.
Springs 14 and 14a are sized depending upon the diaphragm
valve size and line pressure. Springs 14 and 14a are in
compression. The spring retaining spindle 7 passes through
the center of the inner and outer spring retaining plates
12, 12a and 13, 13a and restricts the springs by use
of a nut against the spring outer plates 13 and 13a. This
arrangement also provides spring force adjustment and balances
the spring forces. The spring inner plates 12 and 12a rest
directly against link pivot pins 22 and 22a, respectively.
~ . ~
1~810~ J. M. BOWMAN - 1
At pivot pins 22 and 22a the spring ~orces are transfexred
from the springs to the links.
The diaphragm spindle to link adaptor 5 is used to
transmit force from the primary links to the diaphragm valve
spindle.
The air motor link adaptor 4 is used to transmit the air
motor force to the secondary links.
Referring to Figs. 9 and 10, there is illustrated
therein one embodiment of a mechanical force multiplier that
may be employed in the diaphragm valve operator of Figs. 8
and 9. The first or primary link unit 1 includes a first
identical pair of spaced parallel link assemblies each having
a link la having one end thereof pivotably connected to
stationary point 19 adjacent adaptor 4, a link lb having one
end thereof pivotably connected to the other end of link la
by pivot pin 22 and the other end thereof pivotably connected
to adaptor 5 hy pivot pin 31, a link ld having one end thereof
pivotably connected to stationary point l9a adjacent adaptor
4 and a link lc having one end thereo pivotably connected
to the other end of link ld by pivot pin 22a and the other
end thereof pivotably connected to adaptor 5 by pivot pin 33.
The secondary link unit 2 includes a second identical
pair of spaced parallel link assemblies each having a link
2a having one end thereof pivotably connected to adaptor 4
by pivot pin 32 and the other end thereof pivotably connected
to links la and lb by pivot pin 22 and a link 2b having one
end thereof pivotably connected to adaptor 4 by pivot pin 30
and the other end thereof pivotably connected to links lc
and ld by pivot pin 22a. The arrangement of the mechanical
force multiplier just described is for a reverse acting
- 13 -
~L08106Z J. M . BOWMAN - 1
mechanical force multiplier with the orientation of the
various links illustrated in Figs. 10 and 11 being that
orientation when the diaphragm valve is in a fully closed
position.
Referring to Figs. 11 and 12, the mechanical force
multiplier is that of Figs. 9 and 10-, but with the diaphragm
valve in a full open position.
The operation of the reverse acting mechanical force
multiplier of Figs. 9 - 12 will now be described. In the
closed position the reverse acting mechanical force multi-
plier appears as illustrated in Figs. 9 and 10. Springs 14
and 14a o~ Fig. 7 act on the primary link unit 1 with
minimum spring force. However, the links are in a position
where the force multiplying effect is a maximum; thus, high
force is delivered to the diaphragm spindle 6 of the diaphragm
valve thereby closing this valve. To open the diaphragm
valve the top chamber of the air motor 16 of Fig. 7 is
pressurized. As the air motor spindle 3 moves down, the
secondary link unit 2 push the pivot pins 22 and 22a out-
board, compressing springs 14 and 14a of Fig. 7. The upper
primary links la and ld rotate on the stationary link pins
19 and l9a, respectively, thus the angle of the links of
the primary link unit starts to decrease resulting in smaller
force multiplying effects. However, springs 14 and 14a
are being compressed so the resultant output force to the
diaphragm of the diaphragm valve remains fairly constant.
During this time the links of the secondary unit 2 are moving
from a low force multiplying effect to a higher force multi-
plying effect. As the pivot pins 22 and 22a move outboard,
the adaptor 5 is allowed to move up, opening the valve.
': .
1~8~6Z J. M. BOWMAN - 1
Finally at a full open position, the links of the mechanical
force multiplier are as shown in Figs. 11 and 12. The
stationary points 19 and l9a have not moved. The air motor
spindle 3 has moved down. The diaphragm spindle 6 has moved
up. The springs 14 and 14a are in maximum compression.
To close the diaphragm valve, air pressure i5 released
from the air motor. The spring Force moves the linkæ of the
mechanical force multiplier back to the position shown in
Figs. 10 and 11.
Referring to Figs. 13, 14, 15 and-16, there is illustrated
diagrammatically the link configuration for a direct acting
mechanical force multiplier. Figs. 13 and 14 illustrate this
embodiment of the mechanical force multiplier in the diaphragm
valve full open position, while Figs. 15 and 16 show the
mechanical force multiplier in the diaphragm valve closed
posltlon.
- The direct acting mechanical force multiplier is built
around a yoke as is the reverse acting mechanical force
multiplier as illustrated in Figs. 7 and 8. All aspects of
the yoke pertaining to the reverse acting mechanical force
multiplier of Figs. 7 - 12 also apply to the direct actin~
mechanical force multiplier of Figs. 13 - 16.
The springs 14 and 14a of Fig. 7 are sized depending on
diaphragm valve slze. The springs are in compression. The
spring retaining spindles 7 as shown in Fig. 7 pass
through the center of the inner and outer spring retain-
ing pIates 12, 12a and 13, 13a, and are attached to
the spring retaining spindle connector 9 as illustrated
in Figs. 13 - 15. Connector 9 is required to bridge the
diaphragm valve spindle 6 which must pass through it. The
- - 15 -
~0~106Z J. M. sowMAN - 1
spring retaining spindles 7 res~rict the springs 14 and
14a by use of a nut against the spring outer plates 13 and
13a, provided spring force adjustment, and balances the spring
forces from both springs. The spring inner plates rest
directly against pivot pins 22 and 22a. It is these pivot
pins at which the spring forces are transferred directly to
the links.
The valve diaphragm spindle to links adaptor 5 is used
to transmit force from the primary links 1 to the diaphragm
spindle 6.
Forces from the air motor to the air motor link adaptor
4 are transferred by means of an intermediate adaptor 11 and
an air motor link adaptor to intermediate adaptor rods 8.
The forces are then transferred to the secondary link unit 2.
The first link unit includes link adaptor 5 having a
force transferring relationship with diaphragm spindle 6 and
a first identical pair of spaced parallel link assemblies.
These link assemblies include a link la having one end thereof
pivotably connected to one end of link adaptor 5 by pivot pin
34, a link lb having one end thereof pivotably connected to
the other end of link la by pivot pin 22 and the other end
thereof pivotably connected to a stationary point 19' adjacent
spindle 6, a link ld having one end thereof pivotably con-
nected to the other end of link adpator 5 by pivot pin 35
and a link lc having one end thereof pivotably
connected to the other end of link ld by pivot pin
22a and the other end thereof pivotably connected to a
stationary point l9a' adjacent spindle 6. The second link
unit 2 includes a second identical pair of spaced parallel
link assemblies each having a link 2a having one end thereof
- 16 -
,, '
'` I
.
~081(~2 J. M. BOWMAN - 1
pivotably connected to adaptor 4 by pivot pin 31 and the
other end thereof pivotably connected to links lc and ld by
pivot pin 22a and a link 2b having one end thereo pivotably
connected to adaptor 4 by pivot pin 33 and the other end
S thereof pivotably connected to links la and lb by pivot pin
22.
The operation of the embodiment of the mechanical force
multiplier of Figs. 13 - 16 are as follows. In the open
position, ~he direct acting mechanlcal force multiplier
appearance is similar to the arrangement shown in Fig. 7. The
springs 14 and 14a act on the primary or first link unit 1
to keep the diaphragm valve open. The primary link unit 1
at this point is in position where the force multiplying ~
effect is at a maximum. To close the diaphragm valve, the
bottom chamber of the air motor 16 is pressurized. As the
air motor spindle 3 moves up, the secondary or second link
unit 2 push pivot pins 22 and 22a outboard, compressing the
springs 14 and 14a as illustrated in Figs. 13 - 16. The
lower links lb and lc of the primary link unit 1 rotate
outboard about the stationary pivot pins 19' and l9a',
respectively, thus the angle of the links of primary link unit
1 starts to decrease. As the links of primary unit 1 rotate
outboard they pull down link adaptor 5, closing the diaphragm
valve, moving from a high force muItiplying effect to a
smaller force multiplying effect. During this time, the
links of the second link unit 2 are moving from a low force
multiplying effect to a higher force multiplying effect as
adaptor 4 moves up. Finally, at a full closed position, the
linkage of the two link units look as illustrated in Figs. 15
and 16. The stationary points 19' and 19a' have not moved.
-- 17 --
~ O ~ ~ O ~ Z J. M. BOWMAN - 1
The air motor spindle 3 has moved up. The diaphragm valve
spindle 6 has moved down to close the diaphragm valve. The
springs 14 and 14a of Fig. 7 are compressed to reopen the
diaphragm valve.
To open the diaphragm valve, air pressure is released
from the air motor 16. The forces of springs 1~ and 1-4a move
the links of the two link units back to the position as
illustrated in Figs. 13 and 14.
As illustrated in Figs. 7 - 16, two springs 14 and 14a
are used, one on each side of the mechanical force multiplier.
It is possible to use only one spring. For instance, the
spring retaining rod 7 would extend through spring plate 13,
spring 14, inner spring plate 12 and inner spring plate 12a.
It should also be noted that spring plate 13a, spring 14a, retaining
rod 7, inner spring plate 12a and inner spring plate 12 could
be used by itself in place of the single spring arrangement
just described.
In addition to the direct acting mechanical force multi-
plier as shown by the link configuration in Figs. 13 - 16, there
are two other link configurations that can be used for direct
acting mechanical force multipliers for controlling diaphragm
valves.
The first configuration is illustrated in Figs. 17 - 20.
As shown in Figs. 17 - 20, the link configuration of the link
units of the mechanical force multiplier are the same as
illustrated in Figs. 13 - 16. The difference between these
two mechanical force multipliers is that the two springs
mounted on the side, used to return the diaphragm valve to
the open position, have been replaced by one spring 36
disposed between the top cover 37 and diaphragm 38 of air
motor 16. Spring 36 is placed between the upper air motor
- 18 -
lO~U62 J. M. BOWMAN - 1
cover 37 and the air motor diaphragm 38 so that spring 36
will always exert a force down on air motor spindle 3 forcing
the diaphragm valve into the full open position. When air
is supplied through port 39 in the lower chamber of air motor
16, the air motor force counteracts the spring force in
addition to the force in the linkage of the two link units
due to pressure in the diaphragm valve and closes the diaphragm
valve.
The second alternative configuration is illustrated in
Figs. 21 - 24. This direct acting mechanical force multi-
plier is similar to that illustrated in Figs. 17 - 20 in
that the spring 36 is located between the upper air motor
cover 37 and the air motor diaphragm 38 as illustrated in
Fi~. 17. However, as illustrated in Figs. 21 - 24, the
reverse acting link configuration of the two link units 1
and 2 as illustrated in Figs. 9 - 12 is used as the linkage
arrangement for the two link units 1 and 2 for this direct
acting mechanical force multiplier. Spring 36 in air motor
16 exerts a force down onlair motor spindle 3 which forces
the diaphragm valve into the open position. When air is
supplied to air inlet 39 in the bottom chamber of air motor
16, the air motor force counteracts the spring force in
addition to the force in the linkage of link units 1 and 2
due to pressure in the diaphragm valve and closes the diaphragm
valve.
The advantage of using these two types of alternate forms
of the mechanical force multiplier is basically that the
number of parts required is reduced and the mechanicalforce
multiplier will be easier to assemble and less expensive.
-- 19 --
108iO6Z J. M. BOWMAN - 1
The above alternative forms are practical on a direct
acting mechanical force multiplier because of the relatively
small force required to open the diaphragm valve against
vacuum.
Throughout the description of the Figs. 7 - 24 the
operator for the mechanical force multiplier has been
referred to as an air motor. At this point, it should
be noted that the mechanical force multiplier can be used
with any type of operator that provides a linear motion
or any motion that can be converted to a linear motion.
Examples of such alternate operators are: (1) handwheel
operator; (2) electric operator; (3) piston operator;
and (4) in general, any type of operator that could be
conceivably used with the mechanical force multiplier.
Any operator used will be mounted on~top of the
mechanical force multiplier unit as is the air motor as
shown in Figs. 7 and 8.
As examples, primary link unit angles of 45 and
80 with respective force multipliers of 1 and 5.67 have
been used throughout this description. It should be
pointed out that these are only examples and any angle
and associated force multiplier can be used for the
primary link unit and secondary link unit.
While I have described above the principles of
my invention in connection with specific apparatus it
is to be clearly understood that this description is
made only by way of example and not as a limitation
to the scope of my invention as set forth in the objects
thereof and in the accompanying claims.
ACH:vm/gs/ok
11/18/76
- 20 -
