Note: Descriptions are shown in the official language in which they were submitted.
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AXIAL ACTUATOR
BACKGROUND OF THE INVENTION
The invention is in the field of quarter or full turn
valves like butterfly or ball valves. There are various types
of actuators available to turn the shaft of the valves. There
are actuators where the rotatable shaft of the valve is actuated
by an acme drive screw or by ninety degree pneumatic actuators
such as Keystone actuators. There are pneumatic rack and pinion
rotary actuators; where racks are mounted at ninety degrees to
the pinion on the shaft of the valve; pneumatic scotch yoke
actuators; and a helical groove design actuator manufactured by
Helac Corporation (Enumclaw, Washington). There are also
eccentric multi-gear actuators. Engineers have tried to
incorporate as many utilizable features in the actuators as
possible. Thus it is an object of this invention to provide a
universal actuator which will meet the wider needs of the
industry.
It is an object of this invention to provide an actuator
which is compact, economical; concentric and symmetric to the
shaft of the valve in its geometrical design, and has an axial
orientation in the direction of the shaft which drives the
valve.
It is an object of this invention to provide an actuator
which readily can be modified to meet the various requirements
of valves, while retaining its central core feature.
It is an other object of this invention to provide an
actuator which is efficient and can provide maximum torque, with
respect to its relative size, compared to other actuators.
It is an other object of this invention to provide manual
override which is self locking.
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It is an other object of this invention to provide an
actuator having dependable fail safe closure, by means of
springs, in the event of electric or air supply failure.
It is an other object of this invention to provide an
actuator which can be actuated by hydraulic or pneumatic means,
or by means of an electric motor, or manually.
It is an other object of this invention to provide an
actuator which can incorporate in its design multi-springs in
multi-locations of its body.
It is an other object of this invention to provide an
actuator where springs can quickly and easily be taken out from
any chamber or cavity or cavities to modify the functions of the
actuator.
It is an other object of this invention that the parts of
the actuator can be inspected or replaced readily in the field
when the manual override drive takes control of the valve.
It is also an object of this invention to provide an
actuator where a number of springs and their reaction time can
be changed to provide customized torque output to a specific
application.
It is an other object of this invention that the actuator
can also be operated hydraulically by reversible pump.
It is an other object of this invention that the actuator
will have a minimum number of moving seals.
SUMMARY OF THE INVENTION
According to the invention, an axial actuator includes an
outer enclosure forming an interior space with an inner
enclosure within the interior space. A piston is linearly
movable within the interior space of the outer enclosure. A
rotation device such as a gear is positioned at least partially
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within the inner enclosure and is adapted to be secured to the
stem of a valve to be rotated by the actuator. Interconnection
structure supported by the inner enclosure interconnects the
piston and the rotation device so that linear movement of the
piston is connected into rotation of the rotation device. The
interconnection structure can take the form of gears mounted on
the inner enclosure which mate with the rotation device, when
also a gear, and a rack extending from the piston. Movement of
the piston and attached rack causes rotation of the gear which
causes rotation of the rotation device.
In a preferred embodiment of the actuator of the invention,
the axial actuator has a body made of two integrated concentric
cylindrical enclosures of differential height. The space above
the inner enclosure is divided by a piston disk into two parts,
and a third part includes space which lies inside and around the
inner enclosure. Thus, said three parts create three chambers
A, B, and C in the axial direction of the shaft of the valve;
chamber A being farthest from the valve, chamber B being the
intermediate chamber, and C being nearest to the valve, around
the shaft of the valve. A cavity is also provided to encircle
said inner enclosure.
Under the first alternative, said chambers and said
encircling cavity around the inner enclosure accommodate
synchronized functionary means. These means include the piston
disk between chambers A and B; the compression spring in chamber
B, which reacts against said piston disk. Also included, in
chamber C nearest to the valve, is a main bevel gear, which is
connected to the shaft of the valve by means of its hub while at
the same time, on its opposite side its teeth are engaged with
the bevel pinions of the compounded pinions. And on the
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opposite ends of said compounded pinions there are spur pinions
engaged with rack gears which project radially like the arms
from the rim of said piston disk into said cavity encircling
chamber C. Also, said cavity, encircling Chamber C, is shared
by compression springs which react against said piston disk.
The compounded pinion is an assembly of two pinions having a
spur pinion gear on one end and a bevel pinion gear on the other
end of a common shaft. By actuating said piston all the
synchronized functionary components are actuated to actuate the
shaft to open or to close the valve.
Under the second alternative, individual cavities are
provided for compression springs. There are also individual
cavities provided for spur pinions which are engaged with the
rack gears. Said individual cavities lie on a circle around
Chamber C. The difference between this second alternative,
compared to the first, is that the wall of the inner enclosure
is now integrated with the wall of the outer enclosure. The
height of the inner cylindrical enclosure is designed to be
lesser than the height of outer cylindrical enclosure by a
predetermined difference, to accommodate the stroke of a piston
which divides Chamber A from Chamber B. The piston can be
actuated by various means: pneumatic, hydraulic; or by means of
an electric motor or compression springs. Other means include
using a screw shaft or a shaft having helical grooves around its
outer surface, or using a worm and a worm gear override drive.
The invented actuator is designed on the principle that the
vertical distance the rack gears travel, in unison, must produce
a quarter turn of the shaft of the valve through synchronous
means; said means being the compounded pinions, the main bevel
gear and compression springs.
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If a customer needs it, the actuator can be provided with a manual override
drive.
The manual override drive consists of a shaft which is driven from outside the
actuator;
two spur gears and two worms are held in tandem around a worm gear, where said
worms
act as a couple to rotate said worm gear which is integrated with the main
bevel gear in
chamber C. Said worm gear rotates the shaft of the valve. As the actuator is
designed to
meet universal needs of quarter turn valves, the invented actuator can easily
be modified
in the shop or in the field according to the needs of the customer.
Accordingly, in one aspect, the present invention resides in an axial actuator
to
actuate a valve by turning the shaft of such valve, comprising: an outer
enclosure forming
an interior space; an inner enclosure within the interior space of the outer
enclosure; a
piston linearly movable within the interior space of the outer enclosure to
divide the
interior space into two chambers, one chamber including the inner enclosure,
said piston
having racks extending therefrom; a rotation device positioned at least
partially within the
inner enclosure and adapted to be secured to the shaft of the valve to be
rotated by the
actuator, said rotation device including a bevel gear having a hub adapted to
receive the
shaft of the valve to be rotated by the device; and interconnection structure
supported by
the inner enclosure interconnecting the movable piston and the rotation device
to cause
rotational movement of the rotation device upon linear movement of the piston
within the
interior space, said interconnection structure including mating compound
pinion gears
each having a bevel pinion gear and a spur pinion gear, each said compound
pinion gear
being positioned so that the bevel pinion, gear mates with the rotation device
bevel gear
and the spur pinion gear mates with one of the racks extending from the
piston.
THE DRAWINGS
The best mode presently contemplated for carrying out the invention is
illustrated
in the accompanying drawings in which:
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Fig. 1 is a vertical section of the basic design of the axial actuator of the
invention, taken through the two compounded pinions engaged to the main bevel
gear.
Fig. 2 is the same vertical section as in Fig. 1, where an override drive is
installed
in the chamber C of Fig. 1.
Fig. 3 is the horizontal transverse section taken at line 1-1 in Fig. 2.
Fig. 4 is the vertical section taken at line 2-2 in Fig. 2.
Fig. 5 is transverse section 4-4 in Fig. 1, to show the concept of the
invention.
Fig. 6 is the vertical section as shown in Fig. 1, where a threaded screw
drive is
installed in chambers A and C to drive the piston.
Fig. 7 is the same as Fig. 6, except, instead of a threaded screw drive,
helical
grooves are used.
5a
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Fig. 8 is the top view of Fig. 4 taken at line 3-3 by
removing the covers, the piston, and all the gears to expose the
override drive.
Fig. 9 is the same section as in Fig. 3 showing the
alternate design of the override drive.
Fig. 10 is a transverse section 5-5, shown in Fig. 13, for
the second alternative design to mount the compression springs
and compounded pinions, where the main bevel gear in chamber C
is not shown, but compounded pinion are included.
Fig. 11 is a vertical section of the alternate design of
the compounded pinions.
Fig. 12 is a vertical section of another alternate design
of compounded pinions.
Fig. 13 is a vertical section of the actuator for the
second alternative, where a series of individual cavities for
compression springs and racks and compounded pinions encircle
the inner enclosure.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
Except for the manual override drive, all the elements of
the axial actuator are concentric or symmetrically located about
the shaft of the valve, and therefore all of the figures in the
drawings can be studied together. It should be noticed that the
drawings are not to any true scale.
To grasp the concept of this invention quickly, first the
basic design of the actuator in Figs. 1 and 5, and 10 and 13
will be studied. Figs. 1 and 5 together and Figs 10 and 13
together depict two different alternatives for the installation
of the compression springs, the racks, and the compounded
pinions. Under both alternatives, to accommodate functionary
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means to actuate the shaft of the valve, the invented actuator
has three chambers A, B and C, located in the axial direction of
the shaft A. The difference between the two alternatives is
only in the design of the cavities in which compression springs
17 and racks 4B are installed. In Figs. 1, 2, 5 and 10 the
inside diameter or inner surface of enclosures 1 and 3 are shown
by 3M and 1P.
Under the first alternative, the actuator has a body made
of two integrated concentric cylindrical enclosures which have
walls 1 and 3 and covers iF and 3A. The actuator is assembled
from inside chamber C. First, the compounded pinions depicted
by G1, G2, G3 and G4 are mounted in walls 1 and 3, into the
matching opening 13A in wall 3 and matching hole 16 in wall 1.
The compounded pinion shown in Figs. 1, 11 and 12 is made of two
pinions; a bevel pinion gear 14 and a spur pinion gear 15. The
pinions are held together by means of a common stem 13 as shown
in Fig. 1 and Fig. 11, or by a stem 13 which is a shaft for 15
as shown in Fig. 12. It is equally possible that in the
compounded pinion both pinions can share a common shaft. It is
equally possible that both pinions can share a common shaft
which is mounted through an opening from outside the actuator,
and it is kept in place by capping its outer end with a threaded
bolt mounted in wall 1. It is understood that the word "shaft"
defines a shaft which can have composite cross sections; where
it can be circular in cross section in one portion of the shaft
and also it can be rectangular or square in cross section in
another portion of the same shaft, and the diameter of the shaft
can also vary from section to section. The word "stem" will be
synonymous with the word "shaft" as just described. Once the
compounded pinions are installed in their places then bevel gear
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2 along with hub worm gear 23 with cavity 2B is installed over
said compounded pinions and over and around shaft A of the
valve. It should be noted that if override drive is not
installed then 23 is not a worm gear, but only a hub of gear 2
as shown in Figs. 6 and 9. The length of shaft A is depicted by
its two ends 5 and 6. Gear 2 is rotatable, and is held in place
by means of cover 3A, which cover is fastened by bolts 3C and a
partitioner bolt 50. Gear 2 remains rotatable by creating a gap
2E between bevel gear 2 and cover 3A. After placing 3A in
place, ring 18A, bearing spikes 18B, and compression springs 17,
are installed in cavity 18. After this, spring 16A is installed
over cover 3A. After installing spring 16A, piston disk 4,
bearing bolts 4K, spikes 18C and rack gears 4B are installed
where said rack gears 4B engage teeth 12 of spur pinions 15 of
compounded pinions shown by G1, G2, G3 and G4. The rack gears
4B are recessed minutely, as indicated by 1M in Fig. 5, into
wall 1 or into both walls 1 and 3 to prevent their separation by
rotating away from compounded pinions 15. After this, cover 1F
is bolted down by screwing bolts 1H into the threaded holes 1C.
The spikes 18B and 18C keep springs 17 in place. If desired,
then springs 17 can be welded to 18A. Springs can also be
installed by providing corresponding holes in floor 1L and in
cylindrical portion 4J of piston 4. By sinking bolts 4K to
different depths in holes 4A in piston 4, the initial pressure
of the springs against cover 4 can be varied. The geometry of
the heads of bolts 4K is such that once they are installed in
chamber A, then the bolts cannot rotate. Thus the bolts will
maintained their constant height in chamber A. The rack gears
4B shown in Fig. 5 and Fig. 10 are situated in clockwise
position so that the racks' action on the compounded pinions
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produce unidirectional rotation of gear 2. The use of more than
two compounded pinion gears is preferable. In a large size
actuator more than four compounded pinion gears can be used.
With the aid of Figs. 10 and 13, a preferable second
alternative to the installation of springs, compounded pinions,
and racks will be explained now: In Figs. 10 and 13 a portion
of wall 1 and the entire wall 3 are integrated to become a
single expanse which is depicted by 1 in Fig. 10. Each spring
is provided a circular cavity 18A of predetermined depth which
keeps the spring in place. Each cavity parallel to the shaft of
the valve lie on a circle concentric to that shaft between inner
surfaces 3M and 1P. Cavities depicted by 1Z are provided for
racks 4B, and cavities depicted by ly are provided for
compounded pinions G1, G2, G3,and G4 . The true orientation of
two bolts 78 and 79 shown by axis 1-1, and the true orientation
of handle 42, shown by axis 2-2 with respect to the compounded
pinions, are depicted in the Figs 5 and 10. To keep the number
of Figs. to a minimum, different orientations (as shown in the
drawings) of handle 42 and bolts 78 and 79 were assumed. From
here on, the words "shaft"and "stem", when used in explaining
the override drive, will be considered synonymous.
Fig. 1 shows the valve in fully opened position. Air or
any hydraulic media is used in chamber A to push piston 4 away
from cover 1F. Along with piston disk 4 rack gears 4B move
parallel to shaft A, and their engagement with compounded
pinions G1, G2, G3 and G4 cause the rotation of gear 2 which
rotates the shaft of the valve. Figs. 1, 2 and 4 show the hub
of bevel gear 2 to be a worm gear 23, while it is shown as hub
23B in Figs. 6, 7 and 13. Said hub rotates shaft A to open or
to close the valve. The bolts 3C provide a limit beyond which
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the piston disk 4 cannot travel, thus 3c limits the torque which
can be applied against the shaft and the valve. Bolts 3C arrest
any damaging excessive torque. The springs 17 and 16A provide
dependable fail safe closure in the event of air supply failure.
5 When the air supply fails, the springs automatically relax to
push the piston disk 4 back to close the valve.
The actuator can also function without the springs where
pressurized air or any pressurized fluid is used to create
differential pressure in chamber A and chamber B. Chambers B
10 and C are hydraulically communicative, and, therefore, the same
pressure will prevail through them. The actuator depicted in
Figs. 13 and 10 can be operated with a reversible pump, where
chambers A and B are completely filled with the fluid,
preferably lubricating oil. It will be preferred that the
chamber C is also filled with the same media. Chamber B is
isolated from chamber C and from cavities 1Z for the compounded
pinions, by providing gasket 3G and seal 3J, and also by
lengthening cylinder 4J for the full stroke of piston 4. The
inlet openings 1N and 3K are connected to the reversible pump
via tubes ( not shown). Bored duct 3H opens into chamber B at
3L. The reversible pump empties one chamber while filling the
other chamber. Thus, the piston disk is moved and the shaft of
the valve is rotated to close or to open the valve. It is not
required by the invention, but it is preferred that inlet
opening iT be connected to a small spring gage pressurized
reservoir to maintain constant volume of oil in chambers A and
B. If any leak occurs it can be detected. This type of
actuator is powered strictly by the fluid held in its own
reservoir made of chambers A and B, and no outside reservoir for
pressurized fluid is needed, and no springs are required.
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Therefore, cavities 18A for springs can be eliminated.
Restriction barriers 39 and 48, used for the manual override
located in chamber C, will be explained later with the override
drive. The invented actuator is simply placed over flange 9 of
the valve by mounting hub hole 2B of worm gear 23 or hub 23B
over shaft A. The actuator is bolted down by screwing bolts 7
into threaded openings 8. Bushing and seals are shown by 10, 1B
and 4C and 1E.
Figs. 2, 3, 4 and 8 depict the actuator when it is equipped
with an override drive; therefore these Figs. will be explained
together. For clarity, bolt 50 is not shown in Fig. 2. The
override drive can be engaged or disengaged by means of two
bolts 78 and 79 as shown in Fig. 3 or by means of two pins 80
and 81 shown on opposite sides of the actuator in Figs. 4 and 8,
which pins can be actuated simultaneously by mean of the camming
surfaces of grooves 82 and 83 of split ring 84.
As shown in Figs, 3, 4 and 8, the manual override drive has a
common driving spur gear 29 engaged with two spur gears 30 and
31 in chamber C. Gear 29 has stem 25 installed through openings
41 in walls 1 and 3, where shaft 25 is driven by means of handle
42 by mounting it over end portion 26 of 25, and 42 is held to
by means of bolt 43. Two spur gears 30 and 31 and two worms
27 and 20 are held in tandem by means of stems 21 and 22 around
worm gear 23 where, worms 27 and 20 act together as a couple to
25 rotate worm gear 23 which is integrated with the main bevel gear
2 in chamber C. Worm gear 23 is located in cavity 53 and it is
connected to shaft A of valve. Worm 27 with stem 21, and worm
20 with stem 22 are installed inside the opened ended cavities
54 and 28 created in blocks 34 and 35. Ends of 21 and 22 are
depicted by 33 and 32. In Fig. 2 two opposite sides of block 34
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are depicted by 45. The movable blocks 34 and 35 act as
carriages for the override drive which are held in place by the
sides 49 and 49A of barriers 39 and 48. Blocks 34 and 35 share
common compression springs 37 and 38 mounted in oppositely
matching cavities provided in the bodies of the block. Such two
cavities 37A and 38A are depicted in block 34. Two bolts on
opposite sides of the actuator in Figs. 3 and 5 are shown by 78
and 79. Stems of bolts 78 and 79 are held in place by means of
openings depicted by 76 in 1 and threaded opening 74 in 3. Each
bolt is engaged in hole 72 against surface 73 of the block.
Bolts 78 and 79, and springs 37 and 38 mounted in said blocks
form a mechanism which engages or disengages the override drive.
Shown in Fig. 3 these bolts keep block 34 and 35 in check to
engage two helix worms 27 and 20 with worm gear 23 to make a
couple, where one worm is the right hand worm and the other worm
is the left hand worm.
When bolts 78 and 79 are receded, springs 37 and 38 relax to
push blocks 34 and 35 apart, which disengage worms 27 and 20
from the worm gear 23. Also, it simultaneously disengages spur
gears 30 and 31 from spur gear 29. The transverse movement of
block 34 is permitted by space 46 provided between side 47 of
block 34 and inner face 3E of 3; and transverse movement of
block 35 is permitted by space 46A provided between side 47A of
35 and inner face 3E of 3. Cuts 65 and 66 in wall 3 allow the
transverse movement of spur gears 30 and 31.
Broken ring 84 in Fig. 8 which provides the quickest means
to engage or disengage the override drive will be explained now:
The ring 84 can be rotated around cylindrical wall 1 using bolt
handle 74A. The ring 84 rides on ring 85 installed in a groove
around 1. The locking position of pins 80 and 81 against ring
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84 is shown by 73A, where threaded bolt handle 74A secures the
locking of ring 84 with 1. By releasing bolt 74A from 1 the
ring can be rotated counter clockwise till ends 70E of the
camming surfaces of grooves 82 and 83 move over heads 73A of
pins 80 and 81. Springs 37 and 38 push the blocks 34 and 35
apart along with assemblies of gears in tandem. Pins 80 and 81
also are pushed apart against the camming surfaces of grooves 82
and 83 when the override drive is disengaged. The length of
each camming groove 82 and 83 is depicted by 70D and 70 E
respectively. The ring 84 can be a full ring if it is installed
above or below hub 44. This would eliminate conflict with
handle 44.
Fig. 6 is the same as Fig. 1 except that springs are
removed. Operated manually, screw drive is made of
diametrically expansive screw 4G having threads 4J. Screw 4G is
installed in chamber A and chamber B by passing 4G through
threaded opening 4H of 4. Lower stem 4K keeps cover 3A and
bevel gear 2 separated. Narrow sections 4L and 4M keep screw 4G
in rotatable position between covers iF and 3A. Stem 4S is for
the handle to drive the screw. A weather seal in Fig. 6 is
shown by 4T. To cut the weight of the screw, the body of the
screw 4G can be hollowed out by creating cavities like 4W. This
type of screw drive can meet the requirements of valves
requiring very high torque, and it also keeps the valve locked
at any setting. The actuator shown in Fig. 6 also can be
operated by electric motor.
Fig. 7 is the same as Fig. 6 except screw drive of Fig. 6
now is a helical drive. The diametrically expansive cylindrical
body 4G is provided external helical grooves. Outlines of one
groove is depicted by 4N. Each groove is fitted with a tooth 4Z
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provided by a circular opening at the center of cover 4. Two
opposite teeth to travel in their separated grooves are shown by
4Z. Chamber A is provided with compression springs 17A. The
helical drive shown in Fig. 7 is needed when a quick action
quarter turn valve is required in the process. The electric
motor rotates 4S. Upon electrical failure, the springs 17A
relax, and 4 is pushed back to shut the valve in a position as
shown in Fig. 7.
The valve of Fig. 7 can be used as an emergency valve such
as a fire sprinkler system valve, so that upon a fire alarm
sensing an alarm condition, electrical power to the motor is
interrupted to operate the actuator. In this case, operation of
the actuator by springs 17A would be arranged to open the valve
rather than shut it, although, in some cases, it may be
desirable to shut a valve in case of fire or other alarm
condition. An alternate arrangement for emergency valve
operation is to hold or lock the actuator in actuated position
with a solenoid or other remotely operated device and upon
sensing of an alarm condition, release the device to allow the
springs or other biasing means to operate the actuator and move
it to the unactuated position as shown in Fig. 7.
Fig. 9 is the same as Fig. 3 except, that spur gear 29 is
eliminated and spur gear 30 is linked-directly to stem 25 which,
as in Fig 3, is rotated by handle 42 to actuate the override
drive. In this modification of design, before the separation of
blocks 34 and 35, stem 25 has to be freed from the spur gear 30.
Stem 25 along with compression spring 98 is mounted from inside
the actuator before assembling other parts of the actuator.
Once stem 25 with spring 98 is mounted in place, then two halves
of a split nut 101 are mounted over the threaded portion of 103
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of stem 25. The nut 101 has internal and external threads
depicted by 102 and 100. Then nut 99 is mounted over nut 101,
and handle 42 locks nut 101 in place. By advancing nut 99
toward the actuator, end portion 95 and 96, of 25, is pulled out
5 of spur gear 30, and blocks 34 and 35 can be separated as
explained earlier. On relaxing the spring 98, end 95 of 25 is
linked again with the spur gear 30. The advantage of using only
two spur gears as in Fig. 9 is that when 25 is rotated clockwise
the spur gear 30 is also rotated clockwise and spur gear 31 is
10 rotated counterclockwise. Thus two right hand helix worms can
be used to make a couple around worm gear 23. But in Fig 3. one
worm has to be the right hand worm and the other worm has to be
the left hand worm to create a couple around worm gear 23.
Unlike any other actuator, the invented actuator needs only
15 a single moving seal 4C which is a benefit in many applications.
This Actuator is symmetric, compact and versatile comparative to
other actuators. It is understood that the actuator is made of
metals. The embodiment and the components of the actuator can
equally be made from various types of engineering material
including plastics currently used in the industry. It is
understood that the design and the number of seals and bushing
can be modified according to the requirements of the customer.
Further, springs can be mounted in any chamber or chambers or
springs can be eliminated from any chamber or chambers, as
required by the customer. It is understood that means to hold
an electric motor, and other accessories to mount hydraulic or
pneumatic means, will be incorporated on or around the actuator.
It is also understood that if springs 16A are not used in
chamber B in Fig. 1 and 2 then cover 3A is not required; washers
fastened to 3 by means of bolts 3C will be sufficient to keep
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gear 2 in rotatable position. It also is understood that
various types of covers for enclosures different from the covers
shown in the drawings can be used without changing the
functionality of the actuator. It is understood that various
changes may be made in adapting the invention to different
embodiments without departing from the broader inventive
concepts disclosed herein and comprehended by the claims that
follow.
