United States Patent (19)
`English
`
`(54)
`76)
`
`TRIBOMETER
`
`Inventor: William English, 1050 Lovely La.,
`Ft. Meyers, Fla. 33903
`
`21)
`
`Appl. No.: 888,842
`
`22)
`
`(51)
`52)
`58)
`
`Filed:
`
`May 27, 1992
`
`Int. Cl. ............................................. GON 19/02
`U.S. C. ................
`Field of Search ......................................... 73/7-10
`
`- P - - - - 73/9
`
`a - O - O -
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`(56)
`
`References Cited
`U.S. PATENT DOCUMENTS
`2,299,895
`10/1942
`Harrall et al. .
`2,955,455
`10/1960
`Frederik .
`Long .
`3,020,744
`2/1962
`Beauchamp .
`3,098,377
`7/1963
`3,427,859
`2/1969
`Taub ......................................... 73/7
`3/973
`3,721,115
`Kearns .
`Majcherczyk .
`4,081,989
`4/1978
`Hayashi .................................... 73/7
`4,130,007
`12/1978
`4,173,885
`Matlock .
`1/1979
`Brungraber .
`4,798,080
`1/1989
`English .
`4,895,015
`1/1990
`
`
`
`IIIHHHHHHHHHHIII
`
`USOO5259236A
`Patent Number:
`11
`(45) Date of Patent:
`
`5,259,236
`Nov. 9, 1993
`
`OTHER PUBLICATIONS
`Murphy, "Crutch or Cane Tip Slippage on Wet Tile vs.
`Velocity at Contact' Draft Revision-Not Dated.
`Slipping Cane and Crutch Tips-Part I-Static Perfor
`mance of Current Devices; Leon Bennett, M. A. E. and
`Eugene F. Murphy, Ph.D., Bulletin of Prosthetics Re
`search for 1977, pp. 71-90.
`Primary Examiner-Robert Raevis
`Attorney, Agent, or Firm-Dickstein, Shapiro & Morin
`(57)
`ABSTRACT
`A tribometer which approximately duplicates the forces
`exerted on a test surface by a human foot or cane tip
`during the walking process. The force exerted on the
`test surface by a test specimen is provided by a fluid
`actuated cylinder supplied with a compressed fluid.
`This force is applied during a sufficiently short period
`of time so as to avoid the absorbtion and squeegee ef.
`fects normally encountered when testing wet surfaces.
`The coefficient of friction for the test surface is then
`determined by measuring the angle of incidence at
`which the test specimen will slip when brought into
`contact with the test surface.
`
`17 Claims, 8 Drawing Sheets
`
`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 1
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`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 1 of 8
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`5,259,236
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 2
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`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 2 of 8
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`5,259,236
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 3
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`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 3 of 8
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`5,259,236
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`20
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`109
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`109
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`AR
`MOTOR
`COMPRESSOR
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`FIG. 5
`7
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`14
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`|| | l
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`36
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`37
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`35
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`FIG. 6
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`ELECTRONIC
`TIMER
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`17
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 4
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`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 4 of 8
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`5,259,236
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`&S3 SS
`?X
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`SSSSSS3
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 5
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`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 5 of 8
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`5,259,236
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`DIGITAL
`CONTROL
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`MICRO
`PROCESSOR
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`141
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`MODULE
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 6
`
`

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`U.S. Patent
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`Nov. 9, 1993
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`Sheet 6 of 8
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`5,259,236
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 7
`
`

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`U.S. Patent
`
`Nov. 9, 1993
`
`Sheet 7 of 8
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`5,259,236
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 8
`
`

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`U.S. Patent
`
`Nov. 9, 1993
`
`Sheet 8 of 8
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`5,259,236
`
`FIG. 13
`
`
`
`2S
`W.
`Sé
`77 5) la),
`
`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 9
`
`

`

`1
`
`TRBOMETER
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`5,259,236
`2
`tor dependent variables. These operator dependent
`variables tend to bias the results of the slip tests so that
`consistent results are difficult to achieve.
`A further limitation exists in devices which utilize
`gravitational force. This limitation results in the inabil
`ity to obtain valid results on inclined surfaces without
`recalibration. Since it is often necessary to determine
`the coefficient of friction of an inclined surface, this
`inability substantially limits the application of these
`devices.
`
`O
`
`BACKGROUND OF THE INVENTION
`The present invention relates to a tribometer for test
`ing the slip resistance of various surfaces. More particu
`larly, the present invention relates to a portable variable
`incidence tribometer, for measuring the slip resistance
`of wet or oily surfaces as well as dry, which approxi
`mates the forces present during the walking process.
`A tribometer is a device used for measuring surface
`friction. Tribometric devices utilize various methods
`for determining the frictional force present when one
`surface is pulled or pushed across another under a cer
`tain predetermined pressure. These devices fall within
`three generally recognized categories; (1) dragsled, (2)
`articulated strut and (3) pendulum type testers. Numer
`ous tribometric devices in each category exist, which
`are disclosed in a number of United States Patents,
`which test the frictional forces between different dry
`20
`surfaces.
`One problem which exists and which is not overcome
`by these devices is obtaining consistent surface friction
`results on surfaces which are wet or have lubricating
`contaminants thereon. Because of the increased risk of
`25
`slippage which exists when a surface is wet a reliable
`method of testing these surfaces is needed.
`In situations where it is desired to determine the slip
`resistance of a wet surface unreliable results can occur
`due to the effects of absorbtion and squeegeeing. These
`30
`effects result in devices where the test specimen is al
`lowed to rest on the test surface prior to motion testing
`so that the contaminants are either absorbed by the test
`specimen or squeezed out from beneath it.
`Attempts have been made to provide devices which
`35
`can reliably test the slip resistance on different surfaces
`including wet surfaces. These attempts are described as
`follows.
`U.S. Pat. No. 4,798,080 discloses a portable apparatus
`which tests the slip resistance of surfaces by substan
`tially instantaneously applying a load to a frictional pad.
`The load in this device is applied using a gravity
`dropped weight or a spring.
`U.S. Pat. No. 4,895,015 discloses a portable horizon
`tal slipmeter in which a stationary pull mechanism ap
`45
`plies a force to a drag sled. The drag sled with the test
`specimen attached is held away from the test surface
`until the device is actuated.
`Leon Bennett, M.A.E. and Eugene F. Murphy,
`Ph.D., Slipping Cane and Crutch Tips, bulletin of pros
`50
`thetics research for 1977, page 71, discloses an instru
`mented walking cane used for testing the slip resistance
`of cane tips on various walking surfaces. Instrumenta
`tion is provided on this device to show the angle of
`incidence and magnitude of the force vector at the point
`55
`where the cane tip slips.
`It has also been suggested to provide a variable inci
`dence mast fitted with an articulated cane that is thrust
`downward at a predetermined angle in order to test the
`slip resistance of a cane tip. This device utilizes an elec
`tric solenoid to provide the downward thrust.
`The prior art devices have many limitations. In par
`ticular, the devices which employ weights, springs or
`solenoids for the thrust force are not representative of
`the forces which are present during the walking pro
`65
`CeSS.
`Additionally, the devices which require the applica
`tion of thrust force by the operator are subject to opera
`
`15
`
`SUMMARY OF THE INVENTION
`The disadvantages of the prior art are alleviated to a
`great extent by the present invention which provides a
`tribometer, which approximates the forces present dur
`ing walking, having a compressed fluid supply means, a
`cylinder means for converting the fluid pressure into a
`linear force, a means for attaching a test specimen to the
`cylinder means, a means for actuating the cylinder
`means, a means for adjusting the angle of incidence of
`the test specimen with the test surface and a means for
`determining the angle of incidence where the test speci
`men slips.
`In one aspect of the invention, a tribometer is pro
`vided which utilizes a compressor to create a fluid pres
`sure which can then be stored. When the device is prop
`erly actuated, the stored fluid pressure is supplied to a
`cylinder which converts this pressure into a linear
`force. A test specimen (which can be a cane tip) is at
`tached to the cylinder by a plug and is thereby brought
`into contact with the test surface at varying angles of
`incidence to determine at what angle the test specimen
`slips.
`In other aspects of the invention the compressor may
`be replaced by a compressed gas cartridge. Further, the
`test specimen may be attached to the cylinder by a ball
`and socket arrangement or swivel joint.
`In utilizing fluid pressure in accordance with the
`tribometer of the present invention a method of deter
`mining slip resistance on lubricated or dry surfaces is
`achieved which more closely approximates the forces
`present during walking. Since the present invention
`operates using fluid pressure in a self contained system,
`rather than gravity, it can achieve consistent results on
`both level and inclined surfaces and is not subject to
`operator independent variables.
`It is an object of the present invention to provide a
`consistent and reliable method of testing the coefficient
`of friction of different surfaces including wet surfaces.
`It is a further object of the present invention to pro
`vide a device which measures the slip resistance of
`surfaces under conditions which more closely approxi
`mate the forces present in a human foot or cane tip
`during the walking process.
`It is a further object of the present invention to pro
`vide a device which can accurately test the slip resis
`tance on inclined surfaces.
`Additional objects and advantages of the invention
`will be set forth in part in the description which follows,
`and in part will be obvious from the description, or may
`be learned by practice of the invention. The objects and
`advantages of the invention will be obtained by means
`of instrumentalities and combinations particularly
`pointed out in the appended claims.
`
`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 10
`
`

`

`O
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`5
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is an isometric view of a tribometer according
`to a preferred embodiment of the present invention.
`FIG. 2 is a side view of portions of the tribometer of 5
`FIG. 1.
`FIG. 3 is a cross sectional view of a gas actuated
`cylinder used in the tribometer of FIG. 1.
`FIG. 4 is a schematic illustration of the pneumatic
`system of the tribometer of FIG. 1.
`FIG. 5 is a schematic illustration of the electrical
`circuit employed in the axis angle regulation mechanism
`of the tribometer of FIG. 1.
`FIG. 6 is a schematic illustration of the electrical
`circuit for the tribometer of FIG. 1.
`FIG. 7 is a partial cut-away side view showing an
`alternate preferred embodiment of a tester used in the
`tribometer of FIG. 1.
`FIG. 8 is a view like FIG. 7 showing another alter
`nate preferred embodiment of a tester.
`20
`FIG. 9 is a schematic illustration of a circuit for cal
`culating and displaying the coefficient of friction for the
`tribometer of FIG. 1.
`FIG. 10 is an isometric view of a tribometer accord
`ing to a second preferred embodiment of the present
`25
`invention.
`FIG. 11 is an isometric view of the tribometer of
`FIG. 10 as viewed from a different angle.
`FIG. 12 is a schematic illustration of the pneumatic
`circuit for driving the gas actuated cylinder in the tri
`bometer of FIG. O.
`FIG. 13 is a view of a changeable tester for the tri
`bometer of FIG. 10.
`FIG. 14 is a partial cut-away view of the changeable
`tester of FIG. 13.
`DETAILED DESCRIPTION OF PREFERRED
`EMBOEDIMENTS
`Refer now to FIG. 1, there being shown a tribometer,
`generally designated by reference number 100, in accor
`dance with a preferred embodiment of the present in
`vention. The tribometer 100 is constructed of a frame 1
`onto which the remaining elements of the tribometer
`are mounted. Those elements include a compressed
`fluid supply means for creating a fluid pressure, a cylin
`45
`der means for converting the fluid pressure into a linear
`force, an attachment means for attaching a specimen 19
`to the cylinder means, an actuating means for actuating
`the cylinder means to move the test specimen in contact
`with a test surface, an adjustment means for adjusting
`the angle of incidence at which the test specimen is
`brought into contact with the test surface, and a means
`for determining the angle of incidence.
`The compressed fluid supply means includes an air
`compressor 9 which is driven by a compressor driver
`55
`motor 6. Ambient air is drawn into the compressor 9
`and the discharged compressed air is delivered through
`conduits 109 to an air pressure receiver 20. Conduits 109
`are partially hidden from view in FIG. 1 but the paths
`of the conduits of the pneumatic circuit are described in
`detail below with reference to FIG. 4. Receiver 20
`holds a volume of compressed air, which volume is
`sufficient to drive cylinder 3 for one operating cycle
`during operation of the tribometer 100. An adjustable
`pressure regulator 12 and gauge 120 is positioned in the
`65
`conduits 109 between a gas cylinder 3 and the air pres
`sure receiver 20. The regulator 12 monitors the pressure
`in the cylinder 3 and indicates the pressure through a
`
`5,259,236
`4.
`gauge 120 to the user. The user may adjust the regulator
`using knob 110.
`A fluid valve 33 is positioned in the pneumatic circuit
`of conduits 109 between the receiver 20 and the gas
`cylinder 3. When the valve 33 is opened by depressing
`button 16 the compressed air stored in receiver 20 ex
`pands and then a portion of the compressed air is deliv
`ered through conduits 109 and regulator 12 and, at a
`regulated pressure, to cylinder 3.
`The cylinder means for converting the fluid pressure
`to a linear force is depicted in FIG.3 and includes a gas
`actuated cylinder 3, a piston 29 and a piston rod 4 con
`nected to the piston 29. The operation of the cylinder
`means is explained in more detail below with respect to
`FIG. 3.
`The specimen 19 is attached to the cylinder means by
`an attachment means which includes, in the embodi
`ment of FIG. 1, a crutch end plug 18. Plug 18 approxi
`mates the size and shape of the end of a crutch shaft
`used to aid a person in walking. The specimen 19 will be
`driven in contact with the test surface 46 on which the
`tribometer 100 is placed. The dynamic friction between
`a variety of test specimens 19 and test surfaces can be
`measured by varying the combination of the specimens
`19 and the test surfaces.
`The adjusting means includes a mast assembly 2
`which has two arms 210, each of which are connected
`at their respective frame ends 211 to the frame 1 such
`that they are pivotable on mast assembly hinge pins 13.
`Each of the two arms 210 of the mast assembly 2 is
`connected at its respective distal end 212 to an air pres
`Sure receiver 20. A support bracket 48 extends between
`and is connected to each of the two arms 210 of the mast
`assembly 2 at positions 213 on the arms 210 located
`about midway between the respective ends 211 and 212.
`The support bracket 48 provides rigidity to the mast
`assembly 2 and provides a mounting point for the mast
`angle adjustment means, as described in detail below.
`Two connecting tabs 45 are mounted to the air pres
`Sure receiver 20 at a location between the two ends 212
`of the arms 210. A cylinder mounting lug 47 is attached
`at a pivot end 312 of a gas actuated cylinder 3 and is
`mounted between the connecting tabs 45 on a hinge pin
`46 such that lug 47 and cylinder 3 can pivot with respect
`to tabs 45 and receiver 20. Extending downward from a
`piston end of the gas actuated cylinder 3 is a piston rod
`4 onto which a crutch end plug 18 is connected. A test
`specimen 19 is then mounted onto the crutch end plug
`18.
`A protractor 10 is mounted to the frame 1 in the
`proximity of the frame end 211 of one arm 210 of the
`mast assembly 2. The angle A which the mast assembly
`forms with the frame 10, and thus with the test walking
`surface with which the frame is generally parallel, can
`be thus determined by means of an inclination angle
`pointer 11 mounted to the arm 210 of the mast assembly
`2.
`Referring to FIG. 2, a mounting bracket 49 is con
`nected to the Support bracket 48. A hinge pin 50 extends
`through the bracket 48 and the mast end 112 of an axis
`adjustment jack screw assembly 8 to pivotably connect
`the mast end 112 to the bracket 49 and thereby to the
`mast 2 (FIG. 1). The assembly 8 includes a threaded rod
`114 which threads into a threaded socket in the
`threaded end 115 of rod 113. The rod 114 is driven
`either clockwise or counter-clockwise by the adjust
`ment motor 7, thereby lengthening the effective length
`
`30
`
`35
`
`SO
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`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 11
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`of rods 113 and 114 to pivot the mast 2 on hinge pins 13
`direction until the test specimen 19 (FIG. 2) comes into
`to adjust the inclination angle A of the mast 2.
`contact with the test surface 46 (FIG. 2).
`The circuit for driving the adjustment motor 7 is
`After the test specimen has contacted the test surface
`illustrated in FIG. 5. The circuit includes a double pole
`the fluid pressure in the cylinder 3 will continue to build
`double throw axis angle regulator switch 14 which is
`to a maximum pressure determined by the regulator 12.
`connected to the mast access adjustment motor 7. A
`In this way the present invention approximates the
`battery 36 which can be recharged using the battery
`dynamics of the forces present during the walking pro
`charger jack 37 provides the energy for driving the
`cess wherein a foot or cane tip is first placed on the
`ground with a nominal pressure and thereafter the pres
`mast axis adjustment motor 7.
`The construction of the gas actuated cylinder 3 is
`sure is increased as weight is shifted onto the foot or
`illustrated in FIG. 3. The cylinder 3 has a piston 29
`which is normally urged in the direction of the cylinder
`In the embodiment of FIG. 1 the pressure build time
`mounting lug 47 by a spring 28. The gas actuated cylin
`between when the test specimen 19 first comes into
`contact with the test surface 46 and when full pressure
`der 3 is connected to the air pressure receiver 20 (FIG.
`has built up in the chamber 260 and the test specimen, if
`1) through a compressed gas line fitting 31 (FIG. 3) and
`it is going to slip, has begun to slip, is less than or equal
`a connecting hose 109 (FIG. 1). As compressed air is
`to approximately one tenth of a second. The duration of
`released from the air pressure receiver 20 (FIG. 1) the
`this pressure build time is important for approximating
`compressed air fills chamber 260 and begins pressing
`the human walk. The pressure build time should be
`against the piston 29 and piston seal 30 driving the pis
`short enough to substantially alleviate the problems of
`20
`ton 29 in a direction away from the cylinder mounting
`absorbtion of moisture and squeegeeing of moisture out
`lug 47.
`from between the test surface and test specimen on wet
`When the piston 29 is driven away from the cylinder
`surfaces. The gravity drop and solenoid driven systems
`mounting lug 47, the test specimen 19 and crutch end
`for measuring slip resistance cannot duplicate this ac
`plug 18 which are connected to the piston rod 4 are
`tion since all of the force between the test specimen and
`thereby driven downward so that the test specimen 19
`test surface is applied substantially instantaneously in
`will come in contact with the floor or surface to be
`those systems. In contrast, in the present invention, the
`tested.
`specimen contacts the test surface more gently than
`The air pressure which is maintained in the air pres
`gravity or solenoid activation permits. After initial
`sure receiver 20 is generated by the air compressor 9
`contact of the test foot with the test surface, the vector
`30
`(FIG. 1). The air pressure supply (FIG. 4) has a com
`force builds up rapidly but smoothly in a manner similar
`pressor driver motor 6 which drives the air compressor
`to the human walking gait, whereas the gravity and
`9. The air compressor 9 will supply air pressure to the
`solenoid actuated devices initial contact is a rather
`air pressure receiver 20 with excess pressure being ex
`spiked impact, and the vector force drops off sharply,
`hausted through the pressure relief valve 32. When the
`rather than rising after contact, as it does in human
`35
`cycle start button is pressed, air pressure contained in
`ambulation. Because the force vector is applied by gas
`the air pressure receiver 20 will be released through the
`pressure, rather than gravity, the present invention can
`conduits 109 and the pressure regulator 12, which con
`be used on ramps and sloped surfaces without recalibra
`trols the pressure, into the gas actuated cylinder 3.
`tion, whereas gravity devices must be used only on level
`The electronic timer start switch 35 which actuates
`surfaces or they must be recalibrated for the particular
`the solid state delay electronic timer 38 (FIG. 6) will
`slope under test. Unlike gravity operated articulated
`also be actuated when the cycle start button 16 is
`strut devices, the vector force is constant at any angle.
`pressed. The timer 38 allows sufficient time for piston
`In the gravity devices, the force declines progressively
`rod 4 (FIG. 1) to travel downward so that the slip test
`as the angle decreases. Further, the rate of decline is not
`may be performed before the valve return solenoid 34
`linear, rising sharply at relatively acute angles with the
`45
`(FIG. 6) is actuated. When the valve return solenoid 34
`horizontal.
`is actuated, it closes the operating selector valve 33
`Moreover, the use of the pneumatic system provides
`removing the air pressure from the gas actuated cylin
`flexibility in adjusting the pressure build time. The pres
`der 3 and vents the cylinder chamber (FIG. 4). Upon
`sure in the receiver 20, the flow diameter of the con
`venting the cylinder chamber, the force of the spring 28
`duits 109, and other flow resistance passageways, the
`50
`returns the piston to its original position.
`tension and spring rate of the spring 28 can all be ad
`The compressor drive motor 6 is driven by current
`justed to vary the maximum force and the pressure
`supplied to the power cord receptacle 17 (FIG. 6). The
`build time.
`compressor drive motor 6 is turned on and off by means
`Alternatively the steps of actuating the gas actuated
`of a compressor start switch 15 installed on one leg of
`cylinder 3, resetting the inclination angle of the mast for
`55
`the compressor drive motor supply.
`each progressive testing of a specific test surface 26 and
`The operation of the tribometer of FIG. 1 to deter
`test specimen 19, determining the angle at which the
`mine the coefficient of friction between a test specimen
`test specimen 19 will slip and calculating the coefficient
`and a test surface can be understood by referring to
`of friction of the test specimen 19 can all be performed
`FIG. 4. When the button 16 is pressed opening the fluid
`by a microprocessor 40 (FIG. 9). By providing power
`valve 33 fluid will begin to flow through conduits 109
`to the microprocessor 40 via operation select switch
`and regulator 12 into the chamber 260 (FIG. 3) pf the
`215, the manual operation steps described previously
`fluid actuated cylinder 3.
`will be performed automatically.
`Referring now to FIG. 3, when the fluid pressure in
`With the gas actuated cylinder 3 starting at a specific
`the chamber 260 exceeds the force of the spring 28, the
`inclination angle the operating selector valve 33 will be
`65
`piston 29 will move away from the cylinder mounting
`depressed by valve servo 41. This valve servo 41, is
`lug 47. As the pressure in the chamber 260 continues to
`actuated by signals sent by the digital control power
`increase, the piston 29 will continue to move in this
`module 39a through data lines 144. The digital control
`
`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 12
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`module 40 is in turn controlled by the microprocessor
`In another embodiment of the invention, the univer
`through signals sent through data lines 143.
`sal ball joint depicted in FIG. 7 is replaced by a foot
`The test specimen 19 will now be forced towards the
`mold 27a and swivel joint 27 (FIG. 8). The foot mold
`test surface 26 at which time the test specimen 19 will
`27a is chosen to approximate the action of a shoe being
`either slip or will not slip. If the test specimen 19 does
`placed on the test surface during walking. In this em.
`not slip, the proximity switch 42 will remain closed and
`bodiment the foot mold 27a is connected to the piston
`operation of the microprocessor will not be interrupted.
`rod 4 through the swivel joint 27. The spring 22 and
`The microprocessor will then adjust the inclination
`spring stiffness adjustment nut 21 are again used to
`angle of the mast assembly 2 by a predetermined
`maintain the foot mold 27a at an angle to the test floor
`amount, such as one degree. The microprocessor ad
`10
`Surface 26 until such time as the foot mold 27a comes in
`justs this angle through signals sent to the digital con
`contact with the test floor surface 26. Upon coming into
`trol power module 39b across data lines 142. The digital
`contact with the test floor surface 26, the foot mold 27a
`control power module then drives the mast axis adjust
`will rotate so that it will become flush with the test floor
`ment motor 7, through signals sent across data lines 145,
`surface 26. This embodiment of the invention can be
`which in turn drives the axis adjustment jack screw
`used for slip testing of shoes mounted on the mold or
`assembly 8.
`shoe sole materials mounted directly on the mold.
`The microprocessor actuates the valve servo 41 again
`In yet another embodiment of this invention depicted
`to actuate the gas actuated cylinder 3. Again the test
`in FIG. 10 the use of electrical devices is eliminated. In
`specimen 19 is forced towards the test surface 46 and
`this embodiment, the two support arms 250 of the mast
`the switch 42 determines whether the test specimen 19
`20
`63 are pivotably connected to the frame 60 by mast
`slips at the new inclination angle. This process will be
`assembly hinge pins 62. The ends of the support arms
`repeated until the test specimen slips, whereupon the
`252 of the mast 63 are connected to a handle 64.
`proximity switch 42 is opened and the operation of the
`An inclination angle pointer 65 is attached to one arm
`microprocessor 40 is interrupted. The microprocessor
`of the mast assembly 63 to indicate the angle of inclina
`then determines, from the angle which the test specimen
`25
`tion and coefficient of friction on a protractor segment
`19 slipped, the coefficient of friction of the test speci
`66 having a compound scale. A support member 68 is
`men 19 and will generate an appropriate signal to out
`mounted between the support arms 253 below the han
`put. This result is then sent to the digital display 214
`dle and onto which a mounting bracket 69 is attached.
`across data lines 140 and indication of the angle and/or
`The gas actuated cylinder 73 is further pivotably at
`coefficient of friction is displayed to the user.
`30
`tached to the mounting bracket 69 at its distal end 90
`Refer now to FIG. 2. After the test specimen has
`and rests against a second support bracket 67 which is
`come in contact with the floor or test surface 26 onto
`mounted between the support arms 254 below the first
`which the tribometer is placed, if the force exerted by
`support member 68.
`the cylinder is sufficient to overcome the frictional
`The piston rod 75 of the gas actuated cylinder 73 has
`force between the test specimen 19 and the test surface
`a universal ball joint 76 (FIG. 14) attached at the opera
`26, the specimen 19 will slip and the cylinder 3 will
`tional end. As depicted in FIG. 14 a universal ball joint
`pivot at the cylinder hinge pin 46. The angle at which
`socket bottom section 77 having an outer threaded sur
`the test specimen 19 is brought in contact with the test
`face 168 is screwed into the threaded inner surface of
`surface 26 can then be varied by the access adjustment
`the universal ball joint socket upper section 157 to form
`jack screw assembly 8 until a point is reached where the
`a universal ball joint socket around the universal ball
`test specimen 19 no longer slips when the gas actuated
`joint 76. The material to be tested 78 (FIG. 13) is
`cylinder 3 is actuated. The angle A at which the test
`mounted to the bottom surface of the universal ball joint
`specimen 19 no longer slips can then be determined by
`Socket bottom section 77. By providing a two part uni
`use of the inclination angle pointer 11 and protractor 10
`versal ball joint socket the material to be tested 78 can
`and the coefficient of friction (Cp) thereby determined.
`45
`easily be changed by unscrewing the universal ball joint
`One formula for determining the coefficient of friction
`Socket bottom section and replacing it with a another
`is CfF tan A.
`one having a different testing material mounted to it.
`Refer now to FIG. 7 which illustrates an alternate
`As depicted in FIG. 13 a compression spring 153
`embodiment of the attachment means for attaching the
`having a general conical shape can be fitted to the tester
`test specimen to the cylinder means. In the embodiment
`50
`between the universal ball joint socket bottom section
`of FIG. 3, a ball joint arrangement is substituted for the
`77 and an spring stiffness adjusting nut 170. This com
`crutch end plug 18 of the embodiment of FIG. 1. The
`pression spring 153 provides resistance to the flexion of
`universal ball joint of this embodiment includes a ball 23
`the ball joint and returns the test shoe to zero incidence
`which is affixed to the threaded end of the piston rod 4.
`from the force vector for each test.
`The universal ball joint socket 24 rotates about this ball
`Turning now to FIG. 12 when the cycle start button
`and a spring 22 is placed between the universal ball joint
`71 is depressed, the double action operation selector
`socket 24 and a spring stiffness adjusting nut 21. The
`valve 86 which is maintained within housing 158 (FIG.
`spring 22 maintains the cylinder pad 25 which is at
`11) is opened allowing gas pressure from the gas pres
`tached to the base of the universal ball joint socket 24,
`sure receiver 80 to flow through feed hose 172, as regu
`perpendicular to the piston rod 4. The tension of the
`lated by the pressure regulator 81, through the selector
`spring 22 can be adjusted by rotating the spring stiffness
`valve 86 and into the gas actuated cylinder 73 through
`adjusting nut 21. The slider pad 25 is held at an angle to
`the feed hose 72. At the same time, gas will also flow
`the test floor surface 26 until the slider pad 25 comes in
`through selector valve 86 into the secondary actuating
`contact with the test floor surface 26. Once the slider
`cylinder 43 through the pneumatic logic control cycle
`pad 25 comes in contact with the test floor surface 26
`65
`timer 44. When sufficient pressure has built up in the
`the universal ball joint socket 24 will rotate around the
`Secondary actuating cylinder 43, the operating selector
`universal ball joint 23 bringing the slider pad 25 down
`valve 86 will be forced closed and the gas actuated
`flat onto the test floor surface.
`
`40
`
`35
`
`55
`
`Louisiana-Pacific Corporation, Exhibit 1057
`IPR of U.S. Pat. No. 8,474,197
`Page 13
`
`

`

`5,259,236
`9
`10
`cylinder will be vented through feed hose 74, causing
`cylinder means for converting the fluid pressure into
`the piston rod 75 to retract.
`a linear force;
`attachment means for attaching a test specimen to the
`The inclination angle of the mast assembly 63 in this
`cylinder means;
`embodiment can be adjusted by turning the mast axis
`actuating means for actuating the cylinder means so
`adjustment knob 79 depicted in FIG. 11. The rod which
`as to bring the test specimen in contact with the test
`is attached to the adjustment knob 79 has right handed
`surface;
`threading on one end 85 and is screwed into a turn
`adjustment means for adjusting an angle of