Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 1 of 16 PageID #: 23532
`
`
`
`
`
`
`
`Exhibit 59
`
`
`
`
`
`

`

`(12) United States Patent
`Glasson
`
`USOO6234061B1
`(10) Patent No.:
`US 6,234,061 B1
`(45) Date of Patent:
`May 22, 2001
`
`(54) PRECISION SENSOR FOR A HYDRAULIC
`CYLNDER
`
`(75) Inventor: Richard O. Glasson, Whippany, NJ
`
`(73) Assignee: Control Products, Inc., East Hanover,
`NJ (US)
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(*) Notice:
`
`12/1997 Eaton.
`5,694,042
`12/1997 Gardner.
`5,701,793
`5/1998 Petro.
`5,752,811
`FOREIGN PATENT DOCUMENTS
`26 35 614
`2/1978 (DE).
`38 35 782
`4/1990 (DE).
`O325787
`8/1989 (EP).
`0505297
`9/1992 (EP).
`OTHER PUBLICATIONS
`Murakami, T., M. Kato and M. Ota, “Precision Angle Sensor
`Unit for Construction Machinery,” SAE Technical Paper
`Series 972782, Sep. 1997.
`* cited by examiner
`Primary Examiner F. Daniel Lopez
`(74) Attorney, Agent, or Firm-Gibbons, Del Deo, Dolan,
`Griffinger & Vecchione
`(57)
`ABSTRACT
`-
`0
`A Sensor mountable within a hydraulic cylinder provides a
`precision Signal indicative of the position of the piston
`utilizing a non-contacting electromechanical transducer. The
`Sensor includes a flexible connector attached between the
`cylinder piston and a converting element for Sensing the
`displacement of the cylinder piston. The converting element
`U.S. PATENT DOCUMENTS
`comprises a pick-up spool coupled to the other end of the
`92/5 R
`3,403,365 * 9/1968 Richards
`so
`
`1007s. Now I ops R connector and rotatable about an axis. The Spool is under
`4.331700
`11/1980 Studebaker.
`tension from a Spring coupled to the Spool. A lead Screw
`4,286.386
`9/1981 Long ...................................... 33/759
`engages threads on the interior of the Spool, and translates
`along an axis when the Spool rotates. A transducer is
`4,288,196
`9/1981 Sutton, II.
`disposed to Sense the position of the lead Screw, and pro
`4,319,864
`3/1982 Kaufeldt.
`vides an output Signal proportional to the motion or position
`4,386,552
`6/1983 Foxwell ................................. 92/5 R
`4,945,221
`7/1990 Nielsen et al. .
`of the movable element. The transducer may be an LVDT or
`4,989,329
`2/1991 Pullen.
`other non-contacting transducer.
`5,024,250
`6/1991 Nakamura .............................. 92/5 R
`5,341,724
`8/1994 Vatel ...................................... 92/5 R
`5,404,661
`4/1995 Sahm et al. .
`
`(21) Appl. No.: 09/302.701
`(22) Filed:
`Apr. 30, 1999
`Related U.S. Application Data
`(60) Provisional application No. 60/104.866, filed on Oct. 19,
`1998.
`(51) Int. Cl." .................................................. FO1B 31/12
`(52) U.S. Cl. ................................................. 92/5 R; 33/763
`(58) Field of Search
`91/192/5 R. 33/756
`- - - - - - - - - - - - - - - - - - - - - - 33759 761 762 763
`s
`s
`s
`
`(56)
`
`References Cited
`
`13 Claims, 9 Drawing Sheets
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 2 of 16 PageID #: 23533
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 1 of 9
`
`US 6,234,061 B1
`
`FIG. 1
`
`106
`
`FEEDBACK
`SENSOR
`
`10
`
`CONTROLLER
`
`POSITION
`SIGNAL
`
`CONTROL SIGNAL
`
`
`
`
`
`
`
`100
`
`105
`
`104
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 3 of 16 PageID #: 23534
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 2 of 9
`
`US 6,234,061 B1
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 4 of 16 PageID #: 23535
`
`

`

`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 5 of 16 PageID #: 23536
`
`
`
`

`

`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 6 of 16 PageID #: 23537
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 6 of 16 PagelD #: 23537
`
`U.S. Patent
`
`US 6,234,061 B1
`
`May22, 2001
`
`Sheet 4 of 9
`
`
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 5 of 9
`
`US 6,234,061 B1
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 7 of 16 PageID #: 23538
`
`

`

`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 8 of 16 PageID #: 23539
`
`U.S. Patent
`
`May22, 2001
`
`Sheet 6 of 9
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 7 of 9
`
`US 6,234,061 B1
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 9 of 16 PageID #: 23540
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 8 of 9
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 10 of 16 PageID #: 23541
`
`

`

`U.S. Patent
`
`May 22, 2001
`
`Sheet 9 of 9
`
`US 6,234,061 B1
`
`FIG. 7
`
`
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 11 of 16 PageID #: 23542
`
`

`

`1
`PRECISION SENSOR FOR A HYDRAULC
`CYLINDER
`
`US 6,234,061 B1
`
`RELATED APPLICATIONS
`This application claims the benefit of United States Pro
`visional Application Ser. No. 60/104,866, filed on Oct. 19,
`1998.
`
`FIELD OF THE INVENTION
`The invention generally relates to position Sensors, and
`more particularly to linear position Sensors for use on power
`cylinders.
`
`BACKGROUND
`Equipment implementing hydraulic cylinders for
`mechanical movement, Such as excavators and other heavy
`construction equipment, depend upon operators to manually
`control the moveable elements of the equipment. The opera
`tor must manually move control levers to open and close
`hydraulic valves that direct pressurized fluid to hydraulic
`cylinders. For example, when the operator lifts a lift arm, the
`operator actually moves a lever associated with the lift arm,
`causing a valve to release pressurized fluid to the lift arm
`cylinder. The use of levers to control hydraulic equipment
`depends upon manual dexterity and requires great skill.
`Improperly operated equipment poses a Safety hazard, and
`operators have been known to damage overhead utility
`wires, underground wiring, water mains, and underground
`gas lines through faulty operation of excavators, bucket
`loaders or like equipment.
`In addition to the Safety hazards caused by improperly
`operated equipment, the machine's operating efficiency is
`also a function of the operator's skill. An inexperienced or
`unskilled operator typically fails to achieve the optimum
`performance levels of the equipment. For instance, the
`operator may not consistently apply the force necessary for
`peak performance due to a concern over Striking a hazard.
`Efficiency is also compromised when the operator fails to
`drive a cylinder Smoothly. The operator alternately over
`drives or underdrives the cylinder, resulting in abrupt Starts
`and stops of the moveable element and thereby derating
`System performance. As a result, the skill level necessary to
`properly and Safely operate heavy equipment is typically
`imparted through long and costly training courses and
`apprenticeships.
`There have been various attempts at implementing an
`automated control System for use on heavy equipment. One
`such system is disclosed in U.S. Pat. No. 4,288,196. The
`System described therein provides for a computer program
`mable System for Setting the lowermost point of a backhoe
`bucket. In U.S. Pat. No. 4,945,221, a control system for an
`excavator is disclosed. The System attempts to control the
`position of the bucket cutting edge to a desired depth.
`Another position locating System for heavy equipment is
`disclosed in U.S. Pat. No. 5,404,661.
`These Systems and others like them share a common
`feature in that they implement a position Sensor. Typically,
`these Sensors are rotary potentiometers as, for instance,
`Suggested in Murakmi, Kato and Ota, Precision Angle
`Sensor Unit for Construction Machinery, SAE Technical
`Paper Series 972782, 1997. This sensor relies upon a poten
`tiometer which changes a Voltage or current in relation to the
`position of a bucket or boom. Other types of Sensors rely
`upon optical, conductive plastic, or metal-in-glass technolo
`gIeS.
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 12 of 16 PageID #: 23543
`
`15
`
`25
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`2
`It is a disadvantage of these Sensors that they mount to the
`outside of the machinery, thereby exposing them to the
`environment. In the case of heavy equipment, this environ
`ment includes Severe temperatures, excessive moisture, and
`air-borne particulate matter which may infect the Sensor. In
`the case of optical, conductive plastic and metal-in-glass
`technologies, the Sensors would rapidly degrade if used on
`construction equipment. Furthermore, Some of these Sensors
`use contacting components that are Susceptible to wear,
`Vibration and temperature. As a result, no Sensor mountable
`to the outside of heavy equipment or relying upon contacting
`elements has gained widespread use in the industry.
`There have been attempts to overcome the limitations of
`contacting Sensors by using electromagnetic energy. For
`example, the system disclosed in U.S. Pat. No. 4,945,221
`discloses using lasers for Sensing position. OtherS Suggest
`using RF energy or the like to provide a feedback signal.
`These Systems, however, have not replaced the leSS expen
`Sive potentiometers due to their complexity of use and their
`expense.
`AS the demands placed upon actuated machinery
`increases, So does the demand for a low cost, long-life Sensor
`operable in a harsh environment. Despite the development
`of highly Sophisticated control Systems, computer proces
`Sors and application Specific Software, the implementation of
`this technology in electrohydraulic equipment has been
`curtailed by the failure to provide a long-life, cost-effective
`precision Sensor operable in harsh environments.
`SUMMARY OF THE INVENTION
`A Sensor according to the principles of the invention
`provides a precision Signal utilizing a non-contacting trans
`ducer. In an exemplary embodiment, the Sensor mounts
`inside a hydraulic cylinder, away from the harsh
`environment, and provides a voltage or current Signal
`indicative of the position of the piston. The Sensor provides
`a connector, attached between a cylinder piston and a
`converting element, for Sensing the displacement of the
`piston. The converting element converts the cylinder dis
`placement to a proportional displacement of a translating
`member. A precision transducer Senses the displacement of
`the translating member and provides an electrical output
`Signal proportional to the piston movement or to the piston's
`position.
`In one exemplary Sensor according to the principles of the
`invention, a flexible connector Such as a cable is attached to
`the movable element (a piston). The converting element
`comprises a pick-up spool coupled to the other end of the
`connector and rotatable about an axis. The Spool is under
`tension from a recoil mechanism, Such as a Spring, coupled
`to the Spool. A translating member, which can be a lead
`Screw, engages threads on the interior of the Spool, and
`translates along an axis when the Spool rotates. A transducer
`is disposed to Sense a position or motion of the translating
`member, and provides an output signal proportional to, and
`therefore indicative of, the position (or motion) of the
`translating member. The transducer can be a linear variable
`differential transformer (LVDT), which is a non-contacting
`transducer. Of course, other transducers, including those
`using contacting components, can be used.
`For use in a hydraulic cylinder, the Sensor's operation is
`like this. The converting element is attached to a cylinder
`end cap. AS the cylinder piston moves within the cylinder,
`the Spool feeds out or draws in cable, thereby tracking the
`piston's linear displacement. AS the cylinder moves toward
`the Spool, the Spring causes the Spool to wind the cable.
`
`

`

`US 6,234,061 B1
`
`15
`
`35
`
`45
`
`50
`
`25
`
`3
`When the cylinder moves away from the spool, the cylinder
`force overcomes the Spring tension and pulls cable off the
`Spool. The Spool is in threaded engagement with a lead
`Screw. AS the Spool rotates, the Spool and lead Screw convert
`the rotary motion of the Spool to a linear displacement of the
`lead Screw. The displacement is proportional to the piston
`displacement. The lead screw is attached to an LVDT core
`that moves within an LVDT body when the cylinder moves.
`The LVDT delivers an electrical signal at its output, which
`can be configured as a position signal, rate Signal or the like.
`BRIEF DESCRIPTION OF THE DRAWINGS
`A more complete understanding of the invention may be
`obtained from consideration of the following description in
`conjunction with the drawings in which:
`FIG. 1 is a block diagram of an exemplary feedback
`control System for a hydraulic cylinder,
`FIG. 2 shows a perspective of an exemplary cylinder
`according to the principles of the invention;
`FIGS. 3A, B and C show an exemplary sensor according
`to the principles of the invention;
`FIG. 4 shows another exemplary Sensor according to the
`principles of the invention;
`FIG. 5 shows another exemplary Sensor according to the
`principles of the invention;
`FIG. 6 shows another exemplary Sensor according to the
`principles of the invention; and,
`FIG. 7 shows another exemplary Sensor according to the
`principles of the invention.
`DETAILED DESCRIPTION
`A feedback Sensor for a cylinder according to the prin
`ciples of the invention provides a precision signal indicative
`of a piston position with relation to a cylinder. The Sensor is
`durable, maintains a long life, and is configured for use in
`harsh environments. An exemplary Sensor mounts inside a
`hydraulic cylinder, thereby protecting the Sensor, and uses a
`non-contacting transducer to provide the precision signal. A
`40
`converting element converts the motion of the piston to a
`proportional motion of a translating member. The
`transducer, which can be located remotely from the piston,
`Senses the position of the translating member, and provides
`an electrical output Signal indicating the piston's position.
`This signal can be conditioned and used in a feedback
`control System, a user interface, or any System where Such
`a signal is desirable.
`In FIG. 1, a block diagram of an exemplary feedback
`control system 100 is shown. The control system 100
`comprises a hydraulic cylinder 104 actuated by a pump 102
`and a valve 108. AS is known in the art, the pump 102
`delivers hydraulic fluid under pressure to the cylinder 104
`which forces the piston 105 to move with respect to the
`cylinder. The valve 108 controls the flow of hydraulic fluid
`to the cylinder 104. To implement feedback control, a
`feedback sensor 106 senses the position of the piston 105
`and delivers a position signal to a controller 110. The
`controller 110 actuates the valve 108 according to certain
`instructions. The piston 105 may be attached to some other
`apparatus (not shown) whereby a displacement of the piston
`causes a displacement of the apparatus. Although a hydrau
`lic cylinder is shown, it should be apparent that other types
`of cylinders, Such as pneumatic cylinders, can be used.
`Referring to FIG. 2, a hydraulic cylinder 200 that can be
`used in the feedback control system 100 of FIG. 1 is shown.
`The hydraulic cylinder 200 comprises a cylinder enclosure
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 13 of 16 PageID #: 23544
`
`55
`
`60
`
`65
`
`4
`210 and a piston 212. The piston 212 is operable to translate
`in dependence upon hydraulic fluid pumped into the cylin
`der. The cylinder enclosure 210 further includes a base 214,
`and the piston 212 is a moveable element with respect to the
`base. A precision Sensor 218 provides a position related
`Signal acroSS the terminals 219 and 222. For instance, the
`Sensor delivers a signal across the Sensor's terminals indica
`tive of the position “d” in FIG. 2. A high pressure bulkhead
`connector (not shown) provides a mechanism for routing the
`terminals 219 and 222 to the outside of the cylinder enclo
`sure 210. The sensor 218 further comprises a flexible
`connector 216 attached to the piston 212, a converting
`element 220 attached to the base 214 and a transducer (not
`shown). The connector 216 also attaches to the converting
`element 220 and directly imparts the displacement of the
`piston 212 with respect to the base 214 to the converting
`element 220. The converting element 220 converts this
`displacement to a proportional displacement of a translating
`member (not shown). The transducer, located remote from
`the piston, Senses the position or motion of the translating
`member.
`An exemplary embodiment of the converting element 220
`is described with reference to FIGS. 3A, 3B and 3C. A first
`mounting element 302 is provided for attaching the convert
`ing element 220 to, for instance, the base of the hydraulic
`cylinder. A second mounting element 306 and a third mount
`ing element 308 are fixedly attached to the first mounting
`element 302. The converting element 220 includes a rotating
`element 310 rotatably attached between the second mount
`ing element 306 and the third mounting element 308. An
`anti-backlash Spring 312 is mounted to the third mounting
`element 308. Ablock 304 and an anti-rotation spring 305 are
`attached to the first mounting element 302. An arm 320
`attaches to a translating member 324 at one end and engages
`the block 304 at the other. A spring 317 for providing a
`rotary mechanism for the rotating element 310 is housed in
`a spring housing or Spring mounting (not shown). The
`housing is attached to the first mounting element 302.
`In FIGS. 3B and 3C an exploded view of the converting
`element 218 is shown. A press-in hub 316 having a shaft 309
`with internal threads is rotatably attached to a bushing 321.
`The bushing is fixedly attached to the third mounting
`element 308. For ease of installation, the third mounting
`element can comprise an upper half 308A and a lower half
`308B. The translating member 324, having threads formed
`thereon, engages the internal threads of the hub 316. The
`rotating element 310 defines an internal opening into which
`the hub is pressed So that it rotates as the rotating element
`310 rotates. On a side opposite the hub 316, a bushing 322
`fixedly mounts in the second mounting element 306 which
`can also comprise an upper half 306A and a lower half 306B.
`As shown in FIG. 3C, the brackets 306 and 308 define a
`circular opening for attaching the bushingS 322 and 321,
`respectively. An axle 323 attaches to the bushing 322, and
`the rotating element 310 rotatably engages the bushing 322.
`In this exemplary embodiment, the transducer is a linear
`variable differential transformer (LVDT), which has a core
`and a body. The LVDT body acts as the axle 323.
`Alternatively, the LVDT body can be internal to a separate
`axle. The LVDT core 325 is attached to the translating
`member 324 and disposed to translate within the LVDT
`body.
`Operation of this exemplary Sensor is explained with
`reference to FIGS. 2, 3A, 3B and 3C. The flexible connector
`216 attaches to the piston 212 which causes the rotating
`element 310 to rotate in a first direction when the piston 212
`moves away from the cylinder base 214. When the piston
`
`

`

`S
`travels toward the cylinder base 214, the spring 317 causes
`the rotating element 310 to rotate in a direction opposite to
`the rotation caused by the piston moving away from the base
`214. In other words, the flexible connector winds around the
`rotating element 310 when the piston 212 moves toward the
`base 214, and unwinds from the rotating element 310 when
`the piston moves away from the base. The linear motion of
`the piston 212 converts to the angular motion of the rotating
`element 310 via the pulling action of the piston on the
`flexible connector and due to the rotational action of the
`spring 317.
`As the rotating element 310 rotates, the hub 316 rotates
`with it. The hubs internal threads engage threads on the
`translating member 324. AS the rotating element and hub
`rotate, the threaded engagement causes the translating mem
`15
`ber 324 to move linearly along the rotational axis of the
`rotating element 310. The thread arrangement is chosen Such
`that the movement of the translating member is proportional
`to the movement of the piston. The threads can be acme,
`Square, modified Square, buttress, unified, ISO, ball bearing,
`extra-fine pitch or any other of various known threads.
`Likewise, the position of the translating member 324 with
`respect to the transducer is in a one-to-one correspondence
`with the position of the piston 212. The LVDT 323, 325
`Senses a position (or a movement) of the translating member
`and provides a position related Signal.
`The precision and performance of the Sensor is enhanced
`by providing the previously set forth anti-rotation elements
`320, 304 and 305 and anti-backlash elements 320 and 312.
`When the rotating element 310 rotates, causing the trans
`lating member 324 to translate along an axis, there is a Small
`frictional force between the inner threads of the hub and the
`external threads formed on the translating member. This
`Small frictional force is overcome before the translating
`member moves. To overcome this force, the arm 320 is
`provided at an end of the translating member 324. The arm
`320 bends Substantially perpendicular to a longitudinal axis
`of the translating member and engages the block 304. For
`purposes of illustration, the arm 320 is shown engaging the
`block in FIG. 3A such that, when the rotating element 310
`rotates in a counterclockwise direction, the block inhibits the
`arm 320 from turning, thereby overcoming any frictional
`force arising from the threaded engagement.
`The anti-rotation spring 305 applies a force to the arm
`such that it engages the block 304 at Substantially all times.
`The force exerted by this Spring is perpendicular to the
`longitudinal axis of the translating member 324 and is
`chosen Such that it overcomes the frictional force caused by
`the threaded engagement when, with reference to FIG. 3A,
`the rotating element 310 rotates in a clockwise direction. It
`should be apparent that various other equivalent Structures
`can be used to inhibit the motion of the arm 320 when the
`rotating element 310 rotates. For instance, instead of the
`spring 305, another block can be used. Thus, the arm 320 can
`be held between two blocks or a slot formed in one block.
`In any configuration, the anti-rotational forces upon the arm
`320 are such that the arm translates when the rotating
`element 310 rotates.
`In addition to the frictional force inherent in the threaded
`engagement, the tolerances of the threads can introduce a
`dead Space between the threads. For example, when the
`translating member 324 changes direction, due to a change
`in the direction of motion of the piston 212, the piston can
`move Some Small distance before the threads engage. In
`other words, depending upon the thread tolerance, there may
`be play between the threads. This is overcome by the
`anti-backlash spring 312 attached to the bracket 308. The
`
`65
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 14 of 16 PageID #: 23545
`
`45
`
`50
`
`55
`
`60
`
`US 6,234,061 B1
`
`25
`
`35
`
`40
`
`6
`Spring applies a force to the arm 320 directed along the
`translating member's longitudinal axis. This force holds the
`translating member in Substantially constant threaded
`engagement with the internal threads of the hub 316. The
`force exerted by this spring is chosen Such that the trans
`lating member may move against the Spring when the piston
`displaces to cause Such movement.
`It should be apparent that various materials and configu
`rations can be used to implement a Sensor according to the
`principles of the invention. For instance, the rotating ele
`ment 310 can be configured to enhance the performance of
`the Sensor by forming grooves thereon So that the flexible
`connector 216 winds up along Successive grooves of the
`rotating element 310. In this way, no portion of the flexible
`connector 216 lies over another portion. Alternatively, wind
`guides can be used, or for displacements of large magnitude
`relative to the Storage capacity of the rotating element, the
`rotating element can be configured Such that Some portions
`of the flexible connector overlay other portions of the
`flexible connector.
`Likewise, various materials can be used for the flexible
`connector. A connector made of Kevlar®, and materials like
`it, provide desirable attributes, including low Stretch, toler
`ance to a hydraulic fluid environment, and Stability over a
`wide range of temperature (low coefficient of thermal
`expansion). For example, Kevlar(R) is known to have a
`coefficient of thermal expansion on the order of -0.000002/
`degree Farenheit (-2 parts per million per degree Farenheit).
`The connector can also comprise other types of cable, Such
`as metallic cable, Nylon(E), or Stranded cable, and can be
`coated to provide longer life or to adjust the coefficient of
`friction. Its diameter can also be adjusted to meet Storage
`needs on the rotating element or to decrease windage.
`Similarly, the connector can be affixed to the rotating
`element or moveable element by well-known methods, such
`as a clevis, pin, Weld, bolt or Screw, Splice, adhesive,
`threaded terminal, Swayed oval, eye, ball and Socket,
`thimble, or a Strap fork.
`In the embodiment shown in FIGS. 2, 3A, 3B and 3C, the
`transducer is a linear variable differential transformer
`(LVDT). It should be apparent to those skilled in the art that
`other types of transducers can be implemented without
`departing from the principles of the invention, including
`differential variable reluctance transducers (DVRTS(R), wire
`wound potentiometers, conductive plastic potentiometers,
`inductive or capacitive Sensors, Hall-effect transducers, or
`Sensors based upon light emitting diodes, or laser light. In
`each case, the target element for the transducer affixes to the
`translating member. The Sensing element is disposed to
`Sense the motion or position of the target element. Similarly,
`the rotational Spring can be a spiral torsion Spring, a volute
`Spring, a constant force extension Spring, a helical torsion
`Spring, a twisted elastic element, a round tension or com
`pression Spring, a cantilever tension or compression Spring
`or any other type of Spring which may be usable to impart
`a rotational action on the rotating element. Likewise, the arm
`320 can also be a pin or other Similar structure for engaging
`the block 304 and the anti-backlash spring 312.
`Another exemplary embodiment of a Sensor according to
`the principles of the invention is shown in FIG. 4. In this
`embodiment, an LVDT core 424 is caused to translate along
`an axis Substantially parallel to an axis of rotation for a
`rotating element 410. The flexible connector 420 affixes to
`the rotating element 410 and to a movable element (not
`shown). A lead Screw 415 threadedly engages the rotating
`element 410 at one end. At another end, the lead screw is
`affixed to an arm 422. The LVDT core 424 affixes to the
`
`

`

`US 6,234,061 B1
`
`5
`
`15
`
`35
`
`40
`
`45
`
`50
`
`25
`
`7
`other end of the arm 422 and is disposed to translate in an
`LVDT body 426. When the flexible connector is pulled such
`that it unwinds from the rotating element 410, the threaded
`engagement causes the lead Screw 415 to translate. This, in
`turn, causes the LVDT core 424 to translate within the LVDT
`body 426. A recoil mechanism 428 causes the rotating
`element 410 to wind the connector 420 when the moveable
`element (not shown) moves Such that there is no tension on
`the connector 420. This also causes the LVDT core 424 to
`translate within the LVDT body 426. The LVDT thereby
`provides a position related Signal for the movable element
`(not shown).
`Of course, the Sensor can also be affixed in various
`locations within a cylinder. For instance in FIG. 5, a sensor
`500 is shown attached to the cylinder end cap 503 defining
`the piston shaft aperture. The flexible connector 502 is
`affixed to the same Side of the piston as the Shaft. Operation
`of this configuration is the same with respect to FIGS. 2, 3A,
`B, and C.
`It should also be apparent that various mechanical con
`nections can be made between the transducer and the
`converting element of the Sensor. In FIG. 6, an actuated cam
`602 is shown engaged with an LVDT core 604 and with the
`sensor's converting element 606. In FIG. 7, a mechanical
`connection between the converting element 702 and the
`transducer 704 is made via an extension cable 706.
`Likewise, the converting element can be configured in
`various ways without departing from the principles of the
`invention. For instance, gears instead of threads can convert
`the linear displacement of the movable element to the linear
`displacement of the translating member. It should also be
`apparent that for applications with relatively large displace
`ments of the movable element or where an obstruction is
`located between the converting element and the movable
`element, various pulleys, guides or blockS and tackle can be
`provided to route the connector from the movable element to
`the Sensor's converting element.
`It is to be understood that the invention is not limited to
`the illustrated and described forms of the invention con
`tained herein. It will be apparent to those skilled in the art
`that various changes may be made without departing from
`the Scope of the invention and the invention is not consid
`ered limited to what is shown in the drawings and described
`in the Specification.
`What is claimed is:
`1. A Sensor for providing a position related Signal for a
`first element in relation to a Second element, the Sensor
`comprising:
`a flexible connector having a first end attached to the first
`element;
`a rotating element attached to the Second element and
`coupled to a Second end of the flexible connector;
`a translating member in threaded communication with the
`55
`rotating element, wherein a displacement of the first
`element causes a displacement of the translating mem
`ber; and
`a transducer disposed to Sense a position of the translating
`member, wherein the transducer provides the position
`related Signal;
`the Sensor further including:
`a mounting element attached in fixed relation to the
`Second element, the rotating element rotatably
`attached to the mounting element;
`a block attached to the mounting element, the trans
`lating member having an arm extending Substan
`
`Case 1:17-cv-00770-JDW Document 229-12 Filed 10/05/23 Page 15 of 16 PageID #: 23546
`
`60
`
`65
`
`8
`tially perpendicular to a longitudinal axis of the
`translating member; and
`an anti-rotational Spring attached to the mounting
`element and engaged with the arm, wherein the
`anti-rotational Spring exerts an anti-rotational
`force on the arm.
`2. The Sensor of claim 1 further including an anti-backlash
`Spring attached to the mounting element and disposed to
`exert an anti-backlash force along the longitudinal axis of
`the translating member.
`3. A Sensor for providing a position related Signal for a
`piston in relation to a cylinder, the cylinder having a cylinder
`bore, the Sensor comprising:
`a flexible connector having a first end attached to the
`piston;
`a rotating element attached to the cylinder and coupled to
`a Second end of the flexible connector;
`a translating member in dependence with the rotating
`element, wherein a displacement of the piston causes a
`displacement of the translating member; and
`a transducer disposed to Sense the translating member for
`providing the position related Signal,
`the Sensor being disposed in the cylinder bore.
`4. The sensor of claim 3 further comprising hydraulic
`fluid contained within the cylinder so that the transducer is
`exposed to the hydraulic fluid.
`5. The sensor of claim 3 wherein said rotating element is
`a spool having an Outer periphery with wind guides.
`6. The sensor of claim 3 further including an anti-backlash
`force exerted along a longitudinal axis of the translating
`member.
`7. The Sensor of claim 3 further comprising a recoil
`mechanism coupled to the rotating element for imparting a
`rotational action on the rotating element.
`8. The sensor of claim 3 wherein the translating, member
`is in threaded communication with the rotating element.
`9. The sensor of claim 3 wherein the translating member
`displaces along an axis of rotation of the rotating element.
`10. The sensor of claim 3 further including a mounting
`element attached in fixed relation to the cylinder, the rotating
`element rotatable attached to the mounting element.
`11. The sensor of claim 3 further including an anti
`rotational force exerted on the translating member.
`12. A device comprising:
`a cylinder containing a working fluid;
`a piston Slidingly engaged with the cylinder and respon
`Sive