a2) United States Patent
`US 6,851,711 B2
`(10) Patent No.:
`Goertzen et al.
`(45) Date of Patent:
`Feb. 8, 2005
`
`
`US006851711B2
`
`(75)
`
`(54) VEHICLE HAVING AN
`ANTI-DIVE/LOCKOUT MECHANISM
`Inventors: Gerald Goertzen, Brunswick, OH
`way
`‘
`(WS);William A. Null, Jr., Sullivan,
`(US)
`.
`.
`Invacare Corporation, Elyria, OH
`(US)
`
`:
`(73) Assignee:
`
`(*) Notice:
`
`a
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) Appl. No.: 10/643,010
`(22)
`Filed:
`Aug. 18, 2003
`
`
`
`12/1989 Nahachewski
`4,886,294 A
`6/1990 Kimura
`4,934,626 A
`1/1993 Robertsonetal.
`5,176,393 A
`3/1004 Mathis
`ene “
`3/1
`reat, Jr.
`5,290,
`3/1994 Mentessi et al.
`5204141 A
`5/1994 Bussinger
`5,316,328 A
`10/1994 Okamoto
`5,351,774 A
`5,467,838 A * 11/1995 WU cesseccccssssssessesssseeees 180/209
`5,513,875 A *
`5/1996 Tahara et al.
`......... 280/124.162
`5,531,284 A
`7/1996 Okamoto
`5,575,348 A
`11/1996 Goertzenet al.
`5,611,555 A *
`3/1997 Vidal woe. eeeeeeteeeeenee 280/282
`5,853,059 A
`12/1998 Goertzenetal.
`5,964,473 A * 10/1999 Degondaetal. ......... 280/250.1
`6,041,876 A
`3/2000 Pulveret al.
`(List continued on next page.)
`
`(65)
`
`(60)
`
`Prior Publication Data
`US 2004/0094944 Al May 20, 2004
`Related U.S. Application Data
`Provisional application No. 60/404,180, filed on Aug. 16,
`2002,angGisvisional application No. 60/421,178,filed on
`Ch
`2
`ANE
`
`FOREIGN PATENT DOCUMENTS
`2254372
`* 11/1998
`0677285 Al
`10/1995
`0908166 A3
`1908
`WO00/08910
`2/2000
`WO00/09356
`2/2000
`W000/12040
`3/2000
`W0O00/66060
`11/2000
`
`CA
`EP
`EP
`wo
`WO
`WO
`WO
`
`(SL) Unt. C7 cece cscssesescesesesesnens B60G 21/10
`52) US. Ch oo. 280/755; 280/754; 280/124.104
`Primary Examiner—David R. Dunn
`(52)
`:
`755;
`W794;
`y
`.
`.
`-
`(58) Field of Search 0... 280/754, 755,
`Assistant Examiner—George D Spisich
`280/124.104, 124.116, 124.128. 86.1
`ne ne oe (74) Attorney, Agent, or Firm—Calfee, Halter & Griswold,
`References Cited
`LLP
`(57)
`U.S. PATENT DOCUMENTS
`
`ABSTRACT
`
`(56)
`
`A suspension for a vehicle is provided. The suspension
`3/1965 Olson wee 16/35 R
`3,174,176 A *
`includes, for example, a frame andareleasable locking
`3,709,313 A
`1/1973 James
`3,848,883 A
`11/1974 Breacain
`assembly. The releasable locking assembly has, for example,
`3,876,012 A
`4/1975 Regler
`a first assembly movably coupled to the frame, a second
`3,883,153 A *
`5/1975 Singh et al.
`assembly movably coupledto the frame, and wherein move-
`mentof the frame relative to the first and second assemblies
`4,341,278 A
`7/1982 Meyer
`4,437,678 A
`3/1984 Schultz
`causesthe first and second assemblies to engage each other
`4,500,102 A
`2/1985 Hauryet al.
`to limit further movement of the frame in at least a first
`4,556,229 A
`12/1985 Bihler etal.
`direction.
`RE32,242 E
`9/1986 Minnebraker
`4,721,322 A
`1/1988 Hawkins
`4,826,194 A *
`5/1989 Sakita wee 285/302
`
`.......... 280/124.104
`
`80 Claims, 22 Drawing Sheets
`
`
`
`
`
`HP Inc. - Exhibit 1032 - Page 1
`
`HP Inc. - Exhibit 1032 - Page 1
`
`

`

`US6,851,711 B2
` Page 2
`
`U.S. PATENT DOCUMENTS
`
`6,460,641 Bl * 10/2002 Kral voce eeeee 180/24.02
`6,533,306 B2
`3/2003 Watkins
`6.543.564 Bl
`4/2003 Kamenetal.
`6/2000 Dickie etal.
`6,070,898 A
`6,543,798 B2
`4/2003 Schaffneretal.
`6,131,679 A * 10/2000 Pulveretal. ............ 180/65.1
`6,588,799 Bl *
`7/2003 Sanchez ..c.cecceceeseeeee 280/755
`6,209,670 Bl *
`4/2001 Fernie et al. «see 180/12
`2002/0023787 Al
`—-2/2002- Kamenetal.
`6,225,894 Bl
`5/2001 Kyrtsos
`
`6,234,507 BL=5/2001 Dickieetal. 2002/0175027 A1 11/2002 Usherovich
`
`6,341,671 Bl
`1/2002 Ebersole
`2004/0032119 Al *
`2/2004 Tran et al. voce 280/755
`6,347,688 B1
`2/2002 Halletal.
`6,405,816 B1
`6/2002 Kamenetal.
`
`* cited by examiner
`
`HP Inc. - Exhibit 1032 - Page 2
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`HP Inc. - Exhibit 1032 - Page 2
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`U.S. Patent
`
`Feb. 8, 2005
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`Sheet 1 of 22
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`HP Inc. - Exhibit 1032 - Page 3
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`HP Inc. - Exhibit 1032 - Page 3
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 2 of 22
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`HP Inc. - Exhibit 1032 - Page 4
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`HP Inc. - Exhibit 1032 - Page 4
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 3 of 22
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`HP Inc. - Exhibit 1032 - Page 5
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`HP Inc. - Exhibit 1032 - Page 5
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 4 of 22
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`US 6,851,711 B2
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`HP Inc. - Exhibit 1032 - Page 6
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`HP Inc. - Exhibit 1032 - Page 6
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 5 of 22
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`US 6,851,711 B2
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`
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`HP Inc. - Exhibit 1032 - Page 7
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`HP Inc. - Exhibit 1032 - Page 7
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 6 of 22
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`US 6,851,711 B2
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`HP Inc. - Exhibit 1032 - Page 8
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`HP Inc. - Exhibit 1032 - Page 8
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 7 of 22
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`706
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`US 6,851,711 B2
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`HP Inc. - Exhibit 1032 - Page 9
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`HP Inc. - Exhibit 1032 - Page 9
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 8 of 22
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`US 6,851,711 B2
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`FIG.8C
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`HP Inc. - Exhibit 1032 - Page 10
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`HP Inc. - Exhibit 1032 - Page 10
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`U.S. Patent
`
`Feb. 8, 2005
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`Sheet 9 of 22
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`US 6,851,711 B2
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`FIG.9
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`HP Inc. - Exhibit 1032 - Page 11
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`HP Inc. - Exhibit 1032 - Page 11
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`U.S. Patent
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`Feb. 8, 2005
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`HP Inc. - Exhibit 1032 - Page 12
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`

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`U.S. Patent
`
`Feb.8, 2005
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`Sheet 11 of 22
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`US 6,851,711 B2
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`+
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`
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`
`HP Inc. - Exhibit 1032 - Page 13
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`HP Inc. - Exhibit 1032 - Page 13
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`

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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 12 of 22
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`US 6,851,711 B2
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`delSls
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`HP Inc. - Exhibit 1032 - Page 14
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`HP Inc. - Exhibit 1032 - Page 14
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`U.S. Patent
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`Feb.8, 2005
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`Sheet 13 of 22
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`US 6,851,711 B2
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`
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`FIG.12C
`
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`HP Inc. - Exhibit 1032 - Page 15
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`HP Inc. - Exhibit 1032 - Page 15
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`U.S. Patent
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`Feb.8, 2005
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`Sheet 14 of 22
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`US 6,851,711 B2
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`DiyO EROF
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`HP Inc. - Exhibit 1032 - Page 16
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`HP Inc. - Exhibit 1032 - Page 16
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 15 of 22
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`US 6,851,711 B2
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`
`
`FIG.
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`HP Inc. - Exhibit 1032 - Page 17
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`HP Inc. - Exhibit 1032 - Page 17
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`U.S. Patent
`
`Feb.8, 2005
`
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`

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`U.S. Patent
`
`Feb. 8, 2005
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`Sheet 17 of 22
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`US 6,851,711 B2
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`
`HP Inc. - Exhibit 1032 - Page 19
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`HP Inc. - Exhibit 1032 - Page 19
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`U.S. Patent
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`Feb. 8, 2005
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`Sheet 18 of 22
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`US 6,851,711 B2
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` [élOlds
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`HP Inc. - Exhibit 1032 - Page 20
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`HP Inc. - Exhibit 1032 - Page 20
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`U.S. Patent
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`Feb.8, 2005
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`US 6,851,711 B2
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`Sheet 19 of 22
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`FIG.13
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`HP Inc. - Exhibit 1032 - Page 21
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`HP Inc. - Exhibit 1032 - Page 21
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`U.S. Patent
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`Feb.8, 2005
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`Sheet 20 of 22
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`US 6,851,711 B2
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`HP Inc. - Exhibit 1032 - Page 22
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`HP Inc. - Exhibit 1032 - Page 22
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`U.S. Patent
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`Feb.8, 2005
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`Sheet 21 of 22
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`HP Inc. - Exhibit 1032 - Page 23
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`U.S. Patent
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`Feb.8, 2005
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`Sheet 22 of 22
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`US 6,851,711 B2
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`
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`FIG. 17A
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`HP Inc. - Exhibit 1032 - Page 24
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`HP Inc. - Exhibit 1032 - Page 24
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`US 6,851,711 B2
`
`1
`VEHICLE HAVING AN
`ANTI-DIVE/LOCKOUT MECHANISM
`
`CROSS-REFERENCES TO RELATED
`APPLICATIONS
`
`This application claims priority from Provisional U.S.
`Patent Application Ser. No. 60/404,180 filed Aug. 16, 2002
`and Provisional U.S. Patent Application Ser. No. 60/421,
`178, filed Oct. 25 2002, both of which are hereby fully
`incorporated by reference.
`FIELD OF THE INVENTION
`
`The invention relates generally to conveyances and, more
`particularly, to motorized conveyances such as wheelchairs
`and scooters and the like having mid-wheel drives with
`forward and rearward stability systems.
`BACKGROUNDOF THE INVENTION
`
`Wheelchairs and scooters are an important means of
`transportation for a significant portion of society. Whether
`manual or powered,
`these vehicles provide an important
`degree of independence for those they assist. However, this
`degree of independence can be limited if the wheelchair is
`required to traverse obstacles such as, for example, curbs
`that are commonly present at sidewalks, driveways, and
`other paved surface interfaces. This degree of independence
`can also be limited if the vehicle is required to ascend
`inclines or descend declines.
`
`In this regard, most wheelchairs have front and rear
`casters to stabilize the chair from tipping forward or back-
`ward and to ensure that the drive wheels are always in
`contact with the ground. One such wheelchairis disclosed in
`USS. Pat. No. 5,435,404 to Garin. On such wheelchairs, the
`caster wheels are typically much smaller than the driving
`wheels andlocated both forward and rearward of the drive
`
`wheels. Though this configuration provides the wheelchair
`with greater stability, it can hamper the wheelchair’s ability
`to climb over obstacles such as, for example, curbs or the
`like, because the front casters could not be driven over the
`obstacle due to their small size and constant contact with the
`
`ground.
`USS. Pat. No. 6,196,343 to Strautnieks also describes a
`wheelchair having front and rear casters. The front casters
`are each connected to a pivot arm that is pivotally attached
`to the sides of the wheelchair frame. Springs bias each pivot
`arm to limit the vertical movement thereof. So constructed,
`each front caster can undergo vertical movement when
`running over an obstacle.
`While the above-mentioned art provides various ways of
`addressing the need for stabilizing mid-wheeldrive vehicles,
`a need for further stabilization exists. For example, though
`equipped with front and rear suspended casters, most mid-
`wheel drive wheelchairs exhibit various degrees of tipping
`forward or rearward when descending declines or ascending
`inclines. This is because the suspensions suspending the
`front or rear stabilizing casters are compromisedsothat they
`are not madetoo rigid, which would preventtipping and also
`not provide much suspension or are made too flexible
`thereby effectively not providing any degree of suspension
`or stabilization. Hence, a need exists for addressing the
`tipping or “diving” experienced by most mid-wheel drive
`vehicles that have suspension systems included with their
`stabilization mechanisms.
`
`SUMMARYOF THE INVENTION
`
`According to one embodiment, a suspension for a vehicle
`is provided. The suspension includes, for example, a frame
`
`10
`
`15
`
`20
`
`25
`
`30
`
`40
`
`45
`
`50
`
`55
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`60
`
`65
`
`2
`and a releasable locking assembly. The releasable locking
`assembly has,
`for example, a first assembly movably
`coupled to the frame, a second assembly movably coupled
`to the frame, and wherein movementof the framerelative to
`the first and second assemblies causesthe first and second
`
`assemblies to engage each other to limit further movement
`of the frame in at least a first direction.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`In the accompanying drawings which are incorporated in
`and constitute a part of the specification, embodimentsof the
`invention are illustrated, which together with a general
`description of the invention given above and the detailed
`description given below, serve to example the principles of
`this invention.
`
`FIG. 1 is a block diagram of a first embodiment of an
`electronic-based stabilization system.
`FIG. 2 is a block diagram of a second embodimentof an
`electronic-based stabilization system.
`FIG. 3 is a block diagram of a third embodiment of an
`electronic-based stabilization system.
`FIG. 4 is a side elevation overview of a first embodiment
`of a mechanically-based stabilization system.
`FIG. 5 is a partial perspective view of a second embodi-
`ment of a mechanically-based stabilization system.
`FIGS. 6A and 6B illustrate a first embodimentof a locking
`member or assembly.
`FIGS. 7A and 7B illustrate a second embodiment of a
`
`locking member or assembly.
`FIGS. 8A, 8B, and 8C illustrate a third embodimentof a
`locking member or assembly.
`FIG. 9 illustrates a fourth embodiment of a locking
`member or assembly.
`FIGS. 10A, 10B, and 10C illustrate a fifth embodimentof
`a locking memberor assembly.
`FIGS. 11A and 11B illustrate a sixth embodiment of a
`locking memberor assembly.
`FIGS. 12A through 12] illustrate a seventh embodimentof
`a locking member or assembly.
`FIGS. 13-18B illustrate an eighth embodimentof a lock-
`ing memberor assembly.
`DETAILED DESCRIPTION OF ILLUSTRATED
`EMBODIMENT
`
`Generally, a mid-wheel drive wheelchair or scooter is a
`vehicle used to assist those having an impaired ability to
`transport themselves. As such, the mid-wheel drive wheel-
`chairs and scooters of the present invention haveat least two
`drive wheels that are positioned approximately below the
`center of gravity of the vehicle when loaded with a user. This
`results in approximately 85% or moreofthe total wheelchair
`or scooter weight being on the two drive wheels. Mid-wheel
`drive wheelchairs and scooters also include one or more
`
`casters for forward and rearwardstability, respectively posi-
`tioned forward and rearward of the drive wheels. One
`
`example of a mid-wheel drive wheelchair can be found in
`U.S. Pat. No. 5,435,404 to Garin, which is hereby fully
`incorporated by reference.
`At
`least one motor or combination motor/gear box is
`provided to drive the drive wheels. The motor is typically
`controlled by an electronic controller connected to one or
`more user control devices. The user control devices gener-
`ally provide selection of forward and reverse movementof
`the vehicle, as well as controlling the velocity or speed. A
`
`HP Inc. - Exhibit 1032 - Page 25
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`US 6,851,711 B2
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`3
`battery typically supplies the controller and drive motors
`with an energy supply. Dynamic braking and an automatic
`park brake are also incorporated into the vehicle. The
`dynamic brake allows the operator to proceed safely, even
`down a slope, without worrying that the vehicle will unrea-
`sonably increase in speed while going down the slope.
`Further, the park brake automatically engages to hold the
`vehicle in place when the vehicle is standingstill.
`The present invention provides multiple embodiments of
`a stabilization system that provides mid-wheel drive
`vehicles with an anti-dive or lock out mechanism. Generally,
`the stabilization system includes a trigger or sensor for
`sensing when conditions exist that may cause the mid-wheel
`drive vehicle to exhibit a tipping behavior, which can be
`either forward or rearward, and a locking memberor assem-
`bly that locks the suspension system to prevent any further
`tipping behavior. The trigger or sensor also senses whenthe
`mid-wheel drive vehicle is no longer subject to conditions
`that may cause it to exhibit a tipping behavior and causes the
`locking memberor assembly to no longer lock the suspen-
`sion system.
`Referring now to FIGS. 1 and 4, a block diagram ofa first
`embodiment 100 of an electronic-based stabilization system
`is shownand a representative mid-wheel drive wheelchairis
`shown, respectively. Referring more specifically to FIG. 4,
`the mid-wheel drive wheelchair has a frame 402 and pivot
`arm 404. A pivotal connection 406 connects frame 402 and
`pivot arm 404. Attached to pivot arm 404 is a drive wheel
`410. This attachmentis typically provided through a motor
`or motor/gear box that is attached to pivot arm 404. Pivot
`arm 404 further has a front caster 412 attached to a forward
`portion thereof, while the motor or motor/gear box is
`attached to a moredistal opposite portion. Mounting brack-
`ets and/or apertures are provided in pivot arm 404 for
`connecting pivot arm 404 to frame 402 via pivotal connec-
`tion 406. A rear caster assembly 416 is provided that
`includes a frame member 418 and caster 414. Asecond pivot
`arm and assembly is similarly provided on the opposite of
`the wheelchair, as shown in FIG. 5.
`Referring now to FIG. 1, the stabilization system triggers
`a locking memberor assembly whenever the summation of
`moments or torque about pivotal connection 406 exceeds a
`pre-loaded valueor, in other words, causes the frame 402 of
`the wheelchairto tip forward. One of the momentarms that
`influences this loading is the moment arm defined by the
`distance from the center of gravity Cg of the mass of the
`wheelchair occupant and seat 408 to pivotal connection 406.
`The torque or momentacting on the center of gravity Cg is
`generally defined by: (mass of the wheelchair occupant and
`seat)x[(wheelchair acceleration)+(sine of the slope angle)x
`(acceleration of gravity)]. The slope angleis the slope ofthe
`angle measured from a horizontal. For example,
`if the
`wheelchair is traveling on a horizontal surface, the slope
`angle is zero (0) degrees. If the wheelchairis traveling up an
`incline,
`the slope angle may be,
`for example,
`five (5)
`degrees. If the wheelchair is traveling down a decline, the
`slope angle may be, for example, minus five (-5) degrees.
`As such, the present invention is configured to trigger the
`locking member or assembly sooner when traveling down
`declines (i.c., negative slope angle), compared to when
`traveling up inclines (i.e., positive slope angle).
`As illustrated in FIG. 1,
`the system 100 includes a
`controller 101, dive lockout control logic 102, and motor/
`brake logic 103. Controller 101 is any computer-based
`controller suitable for controlling a vehicle. In this regard,
`controller 102 generally has a processor, memory, and
`input/output components (not shown). Controller 101 can
`
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`15
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`4
`also have electric motordrive circuitry associated therewith
`(not shown) that connects to drive motors 104 and 106. A
`user input device 108 such as, for example, a joystick,
`provides control information to the controller 101 for driv-
`ing the wheelchair. A sensor 126 is provided for sensing the
`force acting on the center of gravity Cg of the wheelchair
`occupant and seat and outputs a signal S to controller 102.
`As will be presently described, sensor 126 can be any one of
`several embodiments. The remainder of system 100 includes
`electronic switches 110 and 112, nodes 114, 118, and 121,
`diodes 116 and 120, resistor 122 and solenoid coil 124.
`Solenoid coil 124is part of an electronic locking memberor
`assembly such that the state of the coil (i.e., energized or
`unenergized) defines the state of the locking member or
`assembly (i.e.,
`locking or not
`locking the suspension
`system).
`In operation, controller 101 receives driving command
`inputs from joystick 108. This causes controller 101 to
`output voltages V, and V, and current I, and I, to theleft
`and right motors 104 and 106, respectively. Attached to each
`motor is a motor lock 105 and 107, respectively. All the
`components of the system are typically powered by battery
`having a positive voltage potential B+ and a ground poten-
`tial “Gnd.” The sensor 126 is mounted on the wheelchair so
`as to generate a trigger signal S when the wheelchair is
`tipping forward. In the presently described embodiment, the
`trigger signal S is an electronic signal.
`In other
`embodiments, this can be a mechanical signal such as that
`generated by a push-pull cable assembly.
`Solenoid coil 124 is controlled by the state of electronic
`switch 112. The locking member or assembly associated
`with solenoid coil 124 is preferably in its unlockedstate
`when solenoid coil 124 is energized and inits locked state
`when solenoid coil 124 is unenergized. Alternatively, the
`opposite configuration can also be employed.
`Nodes 114 and 118 and diodes 116 and 120 form an OR
`circuit that controls the state of electronic switch 112 and,
`hence,
`the energy state of solenoid coil 124. More
`specifically, node 114 forms one input to the OR circuit and
`relates to the state of the motor brakes. For example, when
`the motors are being driven,
`the brakes disengage and
`motor/brake logic 103 causes node 114 to be at 5V. This, in
`turn, causes electronic switch 112 to close thereby energiz-
`ing solenoid coil 124 and releasing the locking memberor
`assembly from locking the wheelchair suspension. Whenthe
`motors are not being driven, the brakes are engaged and
`motor/brake logic 103 causes node 114 to be at OV. This
`causes electronic switch 112 to open, which de-energizes
`solenoid coil 124 thereby engaging the locking member or
`assembly to lock the suspension.
`Node 118 forms the second input to the OR circuit and
`relates to input provided by sensor 126 for detecting when
`conditions may exist that indicate the wheelchair maystart
`exhibiting a tipping behavior. More specifically, if sensor
`126 is not
`indicating that conditions exist under which
`wheelchair may exhibit a tipping behavior, dive lockout
`control logic 102 interprets this state and causes node 118 to
`be at 5V. This, in turn, causes electronic switch 112 to close
`thereby energizing solenoid coil 124 and releasing the
`locking member or assembly from locking the wheelchair
`suspension. Whensensor126 sensesthat conditions exist for
`a tipping behavior, dive lockout control logic 102 interprets
`this state and causes node 118 to be at OV. This, in turn,
`causes electronic switch 112 to open thereby de-energizing
`relay 124 and engaging the locking memberor assembly to
`lock the wheelchair suspension.
`Illustrated in FIG. 2 is an embodiment 200 of a stabili-
`
`zation system similar to embodiment 100 of FIG. 1. In
`
`HP Inc. - Exhibit 1032 - Page 26
`
`HP Inc. - Exhibit 1032 - Page 26
`
`

`

`US 6,851,711 B2
`
`5
`the sensor 126 (of embodiment 100)
`embodiment 200,
`includes an accelerometer 204 that produces an acceleration
`input signal A,. to controller 101. Accelerometer 204 can be
`any convention accelerometer that provides an output signal
`that
`is proportional
`to the sensed acceleration.
`In one
`embodiment, accelerometer 204 can be an appropriately
`damped pendulum mercury switch. In another embodiment,
`accelerometer 204 can be an electronic accelerometer such
`
`model no. ADXL202 manufactured by Analog Devices of
`Norwood, Mass. Accelerometer 204 is preferably located on
`or near the wheelchair seat proximate the center of gravity
`Cg of the wheelchair seat and occupant.
`The operation of embodiment 200 is substantially the
`same as embodiment100, exceptthat the state of node 118
`is dependent on acceleration signal A,.. The acceleration
`signal A, is compared by the dive lockout control logic 202
`to a dive threshold acceleration parameter A,,, which may be
`negative (-A,) indicating wheelchair deceleration. The
`value of dive threshold acceleration parameter A, can be
`either calculated based on the weight of the wheelchair and
`occupant or determined experimentally with the actual
`wheelchair and a range of seat occupant weights. As such,
`dive threshold acceleration parameter —A, is a parameter
`that
`is used by the dive lockout control
`logic 202 to
`determine if conditions are present under which the wheel-
`chair may exhibit a tipping behavior. When dive lockout
`control logic 202 determines that acceleration signal A, is
`more negative than dive threshold parameter -Ap,,it drives
`node 118 to OV. This causes electronic switch 112 to open
`thereby de-energizing solenoid coil 124 and causing the
`locking memberor assembly to lock the wheelchair suspen-
`sion. Acceleration signal A, is negative when the wheelchair
`is decelerating or facing a downward slope or decline.
`Otherwise, node 118 is maintained at 5V thereby causing
`electronic switch to close. This, in turn, causes solenoid coil
`124 to be energized thus releasing the locking member or
`assembly from locking the wheelchair suspension.
`Referring now to FIG. 3, an embodiment 300 of an
`electronically-based stabilization system is shown. Embodi-
`ment 300 is substantially similar to embodiment 100, except
`that sensor 126 includes a motor voltage and/or current
`sensor, which can be incorporated into controller 101. In this
`regard, controller 101 can incorporate an analog-to-digital
`(A/D) converter circuit or can include an external A/D
`circuit. This A/D circuit converts analog signals such as, for
`example, voltage or current signals,
`to digital or binary
`signals for input into or interpretation by controller 101.
`Connected therewith, controller 101 also includes dive lock-
`out control logic 302 for interpreting these voltage and/or
`current signals.
`The operation of embodiment 300is substantially similar
`to embodiment 200, except that dive lockout control logic
`302 interprets how hard the motor is being driven and
`dynamically braked to determine whether the locking mem-
`ber or assembly will lock or release the suspension system.
`In this regard, node 114 behavesas earlier described. Node
`118is driven to OV when the wheelchairis traveling forward
`and there is a large amount of dynamic braking being
`generated by motors 104 and 106. Node 118is also driven
`to OV if the wheelchair is accelerating hard in the reverse
`direction of travel. Otherwise, node 118 is driven to 5V. As
`used herein, dynamic braking generally refers to the process
`by which a motor’s windings are short-circuited when the
`motor is not being driven so that the residual rotational
`energy of the motor causes the motor to act as a generator
`that generates a voltage and current. By re-circulating the
`current generated of this configuration, the motor dynami-
`
`10
`
`15
`
`20
`
`25
`
`30
`
`3
`
`40
`
`45
`
`50
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`55
`
`60
`
`65
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`6
`cally brakes itself. The behavior of node 118, as described
`above,is further embodied by Equations (1) and(2) below:
`
`If (V,+Vp)>0 and (i,+lg)<-Ip, then output OV on node 114 Eq. (1)
`
`If (V,+Vp)<0 and U,+lg)>fp, then output OV on node 114 Eq. (2)
`
`In the above equations, V,, Vz, I,, and I, are the approxi-
`mate terminal voltages and currents of motors 104 and 106,
`respectively. Variable I,, is a threshold parameter represent-
`ing a current level that is used to determine when the motors
`are being dynamically braked. The value of threshold
`parameter I,, can be calculated based on the motorspecifi-
`cation and weight of the wheelchair and occupantor deter-
`mined experimentally based on the actual wheelchair weight
`and a range of seat occupant weights. Equation (1) causes
`node 118 to be driven to OV when the wheelchairis traveling
`forward ((V,+V,)>0) and the motors are dynamically brak-
`ing themselves ((I,+I,)<-I,). Equation (2) also causes node
`118 to be driven to OV when the wheelchair is accelerating
`hardin the reverse direction ((V,;+V)<0) and the motors are
`not dynamically braking themselves ((I,+I,)>Ip). As
`describedearlier, when node 118 is driven to OV, electronic
`switch 112 opens thereby causing solenoid coil 124 to
`de-energize. De-energizing solenoid coil 124 causes the
`locking memberor assembly to lock the suspension system.
`Otherwise, node 118is driven to 5V, which causeselectronic
`switch 112 to close thereby energizing solenoid coil 124.
`Energizing solenoid coil 124 causes the locking member or
`assembly to unlock or
`release the suspension system.
`Alternatively, energizing solenoid coil 124 can cause the
`locking memberor assembly to unlock or release the sus-
`pension system and de-energizing solenoid coil 124 can
`cause the locking member to lock the suspension system.
`Referring now to FIG. 4, one embodiment of a
`mechanically-based stabilization system is shown. In this
`regard, a locking member 420, push-pull cable 424, and
`pivotal rear castor assembly 416 are provided. Push-pull
`cable 424 has a first conduit portion attached to a bracket
`430 on rear caster frame member 418 and a second portion
`attached to a locking membercontrol bracket assembly 432.
`Push-pull cable 424also hasa first cable portion attached to
`a rear castor pivot bracket portion 428 and a second cable
`portion attached to a locking membercontrol arm 422.
`Locking member420is pivotally connected to frame 402
`and pivot arm 404. This is accomplished through a conven-
`tional pivot assembly that includes pins or bolts extending
`through mounting brackets. A second similar locking mem-
`ber and push-pull cable are associated with a second pivot
`arm on the other side of frame 402 and identically config-
`ured to locking members 404 and push-pull cable 424.
`In this regard, locking member 420 is preferably a lock-
`able spring device. Examples of such devices include lock-
`able gas or hydraulic springs that
`include piston valve
`assemblies for locking the springs in a predetermined posi-
`tion. Such lockable gas or hydraulic springs include, for
`example,
`the BLOC-O-LIFT®, STAB-O-MAT®, and
`STAB-O-BLOC® models of gas springs as manufactured by
`STABILUS GMBH, Koblenz, Germany. In the preferred
`embodiment, arm 422 is mechanically linked to the recip-
`rocating rod that opens and closesthe piston valve assembly
`of the locking member 404.
`In operation, when rear castor 414 is contacting the
`driving surface, push-pull cable 424 causes arm 422 to be
`pulled toward bracket 432. This state causes locking mem-
`ber 420 to be in its unlocked state thereby allowing pivot
`arm 404 to pivot about pivotal connection 406 as front castor
`412 traverses bumps and obstacles on the drive surface.
`
`HP Inc. - Exhibit 1032 - Page 27
`
`HP Inc. - Exhibit 1032 - Page 27
`
`

`

`US 6,851,711 B2
`
`7
`However, when the wheelchair begins to exhibit a tipping
`behavior (e.g., tipping forward), rear caster 414 will pivot
`about connection 426. Rear castor 414 may or may not
`completely come off of the driving surface. This causes the
`cable within push-pull cable 424 to displace. This displace-
`mentis translated to arm 422, which begins to separate from
`control bracket 432. When arm 422 separates from control
`bracket 432, the locking member enters the locked state
`thereby locking pivot arm 404 from pivotal motion about
`connection 406. When the wheelchair returns to its normal
`
`position, rear caster 414 pivots back to its normal ground-
`engaging position thereby releasing locking member420 via
`push-pull cable 424. This allows pivot arm 404 to once again
`pivot about connection 406. Most preferably, the system is
`configured that if push-pull cable 424 breaks, locking mem-
`ber 420 automatically locks pivot arm 404. Additionally, a
`resilient spring device can be placed between rear caster
`pivot bracket portion 428 and rear caster frame member418
`to bias rear caster 414 around connection 426 towards the
`
`8
`406. As described earlier, solenoid actuator 608 can be
`controlled by any of the embodiments of FIGS. 1-4.
`Assuch, when the wheelchair exhibits a tipping behavior,
`solenoid actuator 608 is de-energized causing spring 612 to
`urge pin 613 and pawl member 614 against ratchet member
`620. This causes pawl member 614 to be locked against
`ratchet member 620 so as to prevent ratchet member 620
`from any further upward motion, which causestipping of the
`wheelchair. This state prevents the forwardportion of pivot
`arm 404 from exhibiting any upward motionthat is associ-
`ated the wheelchair’s tipping behavior. However, it may be
`desirable to allow ratchet member620 to further movein the
`downward direction while pawl member 614 remains
`engaged therewith. This is accomplished by appropriately
`camming the engaging surfaces of pawl member 614 and
`ratchet member 620, as shown. In this manner, pivot arm
`404 is free to move in a direction that would lessen the
`tipping behavior of the wheelchair but not increase such
`behavior. If the wheelchair is not exhibiting a tipping
`behavior or has ceased to exhibit a tipping behavior, sole-
`noid actuator 608 is energized causing pin 613 and pawl
`driving surface.
`member 614 to disengage from ratchet member 620. This
`As an alternative to FIG. 4, push-pull cable 424 can be
`allowspivot arm 404 to freely pivot about connection 406.
`replaced by a limit switch designed to sense the motion of
`As described earlier in connection with FIGS. 4 and 5, one
`rear caster pivot bracket portion 428 and a solenoid actuator
`or
`two or more locking members can be provided.
`configured to act upon arm 422 upon movementof the rear
`Additionally, pawl member614 can betriggered bya inertial
`caster pivot bracket portion 428 during a wheelchair tipping
`switch or method instead of solenoid actuator 608 or one
`motion. In this regard, one or more wires connect the limit
`whichactuates a solenoid actuator.
`switch to the solenoid actuator. In yet another alternative,
`Referring now to FIGS. 7A and 7B, an embodiment 700
`push-pull cable 424 can be replaced with a plurality of
`of a stabilization system having a caliper-type locking
`mechanical linkages that provide the same effect on arm
`422.
`member or assembly 702 is shown. The locking member 702
`Illustrated in FIG. 5 is another alternate embodiment 500
`ha