Note: Descriptions are shown in the official language in which they were submitted.
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INVERTING SPRING ASSEMBLY
BACKGROUND OF THE INVENTION
The present invention generally relates to a spring mechanism. More
specifically,
the invention also relates to the use of a spring mechanism and actuator in a
finished
product including, but not limited to, a pinch valve assembly, manual operated
fluid control
valves, solenoid operated control valves, acceleration sensors, electrical
switches, and snap
action latching mechanisms.
Compression-type springs are known in the art. However, compression-type
springs by their design are limited to resisting an external force from one
specific direction
and are limited to a specific amount of compression distance. The application
of an
external force on a compression spring causes it to compress between the
external force and
the structure to which the spring is attached. There is a maximum distance
that a
compression spring can safely be compressed without damaging the spring. The
single
direction of resistance and the possihility of damage to the compression
spring are
significant limitations for many applications.
Another significant problem area in the prior art pertains to snap action
mechanisms. Examples of devices employing a snapping action between .two
positions are
wall mounted light switches and electrical rocker switches. However, these
devices snap in
one direction or upon application of a small external force, snap in the other
direction. The
main problem with these mechanisms lies in the fact that the amount of force
they can exert
to resist movement from the desired position is limited. There is no known
mechanism that
provides all three desired attributes including: a snap action, a large force
which keeps the
mechanism in the desired position, and a large force that prevents the device
from
remaining in any position between the two distinct switch positions. Industry
addresses the
perfonmance limitations of springs and snap action mechanisms by designing
relatively
complex mechanisms andlor by accepting the performance limitations of the
prior art
devices.
SUMMARY OF THE INVENTION
In one aspect of the invention, an inverting spring assembly includes a
housing, a
metal strip, and an actuator. The housing has a first support, a second
support opposite the
first support, a third support, and a fourth support opposite the third
support. The first and
second supports are at a distance Y from one another. The metal strip is
supported by the
first support and second support and is longer than the distance Y. The
actuator applies
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force to the metal strip in a first direction and a second direction causing
the metal strip to
be movable from a first position and a second position.
In another aspect of the invention, an inverting spring includes a first
support, a
second support, a resilient member and an actuator means. The first support
and second
support are a distance Y apart from one another. The resilient member has a
length greater
than Y. One end of the resilient member is supported by the first support and
the second
end of the resilient member is supported by the second support. The actuator
is in contact
with the resilient member for applying force to the resilient member thereby
allowing the
resilient member to be movable between a first position and a second position
using the
actuator.
In another aspect of the invention, a pinch valve assembly includes a housing,
a
pinch member, and an actuator. The pinch member is slidably disposed of within
the
housing and moves between an extended and a retracted position. The pinch
member is
biased into the extended position and the retracted position. The actuator is
interconnected
with the pinch member such that the actuator biases the pinch member from an
extended
position engaging a soft wall tube to a retracted position disengaging the
soft wall tube.
These and other advantages of the present invention will be further understood
and
appreciated by persons skilled in the art by reference to the following
specification, claims,
and appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a partial fragmentary front elevational view with the third support
member
removed;
Fig. 2 is a partial fragmentary front elevational view with the third support
member
removed showing the resilient member in the second/closed position;
Fig. 3 is a rear perspective view of the inverting spring assembly;
Fig. 4 is a cross-sectional elevational view of the inverting spring assembly
in a
rocker-type switch mechanism in an open state;
Fig. 5 is a cross-sectional view of a rocker switch in the closed position;
Fig. 6 is an alternate embodiment of the inverting spring assembly showing
solenoids supplying force to the resilient member; and
Fig. 7 is a cross-sectional view of an acceleration switch in the open
position
employing the inverting spring assembly.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
The inverting spring assembly of the present invention generally includes a
first
support member and a second support member spaced apart a distance Y, where Y
is any
length; a resilient member of a length X, where X is greater than Y; and at
least one
actuator to supply force to the resilient member. The resilient member is
supported
between the first support member and the second support member creating an
arch in the
resilient member. The inverting spring can be incorporated into an inverting
spring
assembly in which the inverting spring is encased in a housing. For purposes
of example,
the inverting spring assembly will, hereafter, predominantly be described as
used in a pinch
valve context, however, as described below and as will become apparent to
those of
ordinary skill in the art, the assembly is not limited to use as a pinch
valve.
Fig. 1-shows the inverting spring assembly 10 in a pinch valve mechanism. As
shown, the inverting spring assembly includes a resilient member 12, a lever
actuator 14, a
first support member 16, a second support member 18, a third support member
20, and a
fourth support member 22. The resilient member has a length X and is supported
at
opposite ends by first support member 16 and second support member 18. The
first
support member and second support member are spaced a distance Y apart from
one
another where X is greater in length than Y such that resilient member 12
forms an arch.
The greater the difference between X and Y results in a greater arch in the
resilient
member. Varying the arch height varies the force required to invert resilient
member 12
from its first position (Fig. 1) to its second position (Fig. 2). The
resilient member can be
made from a flat strip of metal, preferably spring steel, or plastic and have
varying lengths,
widths and thickness. Typically, more force is required to invert a thick
metal resilient
member than a thin plastic resilient member. The length, width, thickness,
arch height,
and type of material selected for the resilient member can be varied to create
inverting
spring assemblies that resist various amounts of force to accommodate many
uses. Varying
these same parameters also changes the amount of force required to invert the
resilient
member.
As shown in Fig. 3, lever actuator 14 may include a saddle 26 attached
externally to
third support member 20 with a fastener, preferably a bolt 28. Bolt 28 is held
in place with
a spacer, preferably a washer 30, and a cotter pin 32. A lever 34 with a knob
36 is
connected to the base of saddle 26. Actuator saddle 26 also includes a force
lever arm 38
that extends through an opening in third support member 20. Preferably, force
lever arm
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38 is an integral component of the actuator saddle; however, the force lever
arm may be
attached using a fastener or adhesive.
The pinch valve mechanism may further include a pinch member 42 operatively
coupled to resilient member 12 preferably at the center of resilient member 12
for delivery
S of the greatest possible pinching force. As also shown in Fig. 3, force
lever arm 38 of
lever actuator 14 and pinch member 42 both have elongated openings. The
resilient
member is placed through these openings during construction. The location on
the resilient
member that the force lever arm applies force can be varied. If force is
applied in the
center of the resilient member, at the maximum height of the arch, the amount
of force
needed to invert the resilient member to its second position and the travel
distance of the
resilient member at that position are at their greatest amount. As the force
lever arm is
moved away from the center of the resilient member, the amount of force needed
to invert
the resilient member decreases and the travel distance of the resilient member
at the
location where the force lever arm is applying the force also decreases. If
the force is
applied too close to an end of the resilient member, no inversion will occur.
Consequently,
the amount of force the spring can supply can be quite high while the amount
of force
needed to invert the spring can be much lower and may be increased or
decreased, as
desired or as needed.
The pinch member is placed within a first channel 44 in third support member
20
and a second channel 46 in fourth support member 22. The insertion of the
pinch member
into channels 44 and 46, which are preferably parallel and opposite one
another, allows
pinch member 42 to move vertically but not horizontally as resilient member 12
is moved
between first and second positions.
When in use, the pinch valve employing the inverting spring assembly (Figs. 1-
3)
has a tube 48 with soft walls inserted through an aperture 50 in first support
member 16
and a corresponding aperture in second support member 18. Fluid flows through
tube 48
when resilient member 12 is in the retracted first position because the pinch
member is
disengaged from the tube. However, when the resilient member is in the second
position
the pinch member engages the tube. This engagement and the fact the resilient
member
wants to extend to its maximum arch height allows the pinch member to apply a
self
compensating amount of force to keep the tube pinched closed for extended
periods.
As shown in Fig. 2, to move pinch member 42 into the second position with the
pinch member engaging the soft walled tube, the operator of the inverting
spring
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mechanism grasps knob 36 of lever actuator 14 and moves the actuator in a
counter-
clockwise direction (as oriented in Figs. 1 and 2). This movement applies
force to resilient
member 12 through force lever arm 38. This force causes the resilient member
to make an
S-type inversion into an extended and inverted second position thereby forcing
the pinch
member into the soft walls of tube 48 thereby shutting off the fluid flow. An
operator can
later move the lever actuator clockwise thereby moving the force lever arm to
apply a force
upwards on the resilient member causing the resilient member to invert back to
its retracted
first position. This disengages the pinch member from the soft wall tube 48
allowing the
fluid to pass through the tube once again. The dashed lines in Fig. 2 show the
S-type
conversion resilient member 12' undergoes when moving from the first position
to the
second position. At some point during the S-type conversion, the resilient
member reaches
a point where the inverting force of the actuator is no longer required and
the resilient
member completes the inversion without any additional force applied to the
resilient
member.
Figs. 4 and 5 show an alternative embodiment in which a rocker type mechanical
switch is used as an actuator in a pinch valve. This embodiment operates
similarly to the
first embodiment which employs a lever actuator 14; however, a rocker type
actuator 54 is
employed instead of the lever actuator. Fig. 4 shows the pinch member 42
disengaged
from soft wall tube 48 while Fig. 5 shows the pinch member engaging the soft
wall tube.
The rocker type actuator is preferably made of plastic, but can be made from
other
substances as well. The sides and/or the top of the rocker actuator may be
colored to
indicate to the operator whether the pinch valve is open or closed, or if the
inverting spring
assembly is being used in, e.g., an electrical switch, whether the switch is
on or off.
Fig. 6 shows a third embodiment of the present invention, which includes
inverting
spring assembly 10 and two solenoid actuators 56, 58. The solenoids may both
be
positioned on top of the housing, as shown in Fig. 6, or one solenoid placed
above and the
other below the housing (not shown). In this embodiment, upon receiving an
electrical
current, solenoid 56 supplies downward force 60 to resilient member 12 causing
the
resilient member to invert and pinch member 42 to engage soft wall tube 48.
When the
current is switched to solenoid 58, it supplies an upward force 62 to the
resilient member
causing the resilient member to invert and the pinch member to disengage the
soft wall
tubing. The inverting spring assembly only requires that solenoids 56, 58
supply a
momentary force sufficient to invert the resilient member.
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As shown in Fig. 7, one aspect of the invention in which the inverting spring
assembly may be employed, which is not in a pinch valve application, is in an
acceleration
switch. In this application, a mass 64 is interconnected with the resilient
member. Varying
the weight and position of the mass along the length of resilient member 12"
varies the
amount of acceleration or deceleration required to invert the resilient member
and trip the
acceleration switch. When a certain acceleration or deceleration rate is
reached, the mass
causes the resilient member to invert thereby completing the electrical
connection between
electrical contacts 66, 68. The completed connection is shown with the
resilient member
12" in dashed lines in Fig. 7. When the connection is completed, a warning
light
illuminates or some other action occurs warning that the threshold
acceleration has been
reached.
An electrical switch employing the inventive inverting spring assembly would
have
similar electrical contacts to that of the acceleration switch shown in Fig.
7, but may have a
rocker switch or the like as an actuator. Also, it has been contemplated that
a motor or an
air cylinder may be used as an actuator in the inverting spring assembly.
Last, it also has
been contemplated that the entire inverting spring assembly may be injection
molded or
extruded. In this embodiment the resilient member pivotally connected to at
least one of or
both the first support member or second support member. This allows relatively
low
manufacturing cost to be incurred.
The inverting spring assembly has been predominantly described herein as used
in a
pinch valve setting. However, as described herein the inverting spring
assembly may be
used in other finished products as well including, for example, manual
operated fluid
control valves, solenoid operated control valves, acceleration sensors,
electrical switches,
and snap action latching mechanisms. Those of ordinary skill in the art will
find other uses
for the inverting spring assembly beyond these uses and the assembly is not
limited to such
uses.
As shown above, the inverting spring assembly provides a scaleable amount of
force by adjusting the thickness, width, length, material, and the arch height
of the resilient
member to suit desired needs. Also, the resilient member wants to extend back
to its .
maximum arch height. The resilient member of the inverting spring assembly
also
provides a resistive force which increases until the resilient member reaches
a point,
dependent on the thickness, width, length, material, and the arch height of
the resilient
member at which the point the resilient member inverts. The resistive force
occurs from
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both the first position and the second position. The inverting spring assembly
also more
than doubles the total possible travel distance of a conventional compression
spring. The
inverting spring assembly provides a snap action, a large force keeping the
mechanism in
the desired position, and a large force that prevents the device from
remaining between two
distinct switch positions. By providing all of these features in one assembly,
the inverting
spring assembly satisfies a long-felt need.
The above description is considered that of the preferred embodiments only.
Modifications of the invention will occur to those skilled in the art and to
those who make
or use the invention. Therefore, it is understood that the embodiments shown
in the
drawings and described above are merely for illustrative purposes and not
intended to limit
the scope of the invention, which is defined by the following claims as
interpreted
according to the principles of patent law, including the doctrine of
equivalents.
