CA1112214A - Automatic lift assembly - Google Patents

Abstract

ABSTRACT
An improved automatic lift device which consists of a lift carriage that is mounted within the doorway opening so as to be vertically movable therein.
Movable step and riser elements are provided within the lift carriage so as to form normal upper and lower entrance steps in their retracted normal use position.
The lift carriage is selectively movable to a lowered ground level position and a raised interior floor level position while the upper step and riser remain in their retracted normal step position within the lift carriage. The upper step and riser pivotally connected thereto are selectively extendable outwardly and downwardly by self-contained actuating means mounted solely on the base of the lift carriage.
Thus actuated, the upper step and riser-form a continuous horizontal loading platform in association with the fixed lower step formed by the base of the lift carriage. Thus formed, the horizontal loading platform can be selectively lowered to the ground or curb level or to any level intermediate thereto. It can be also selectively raised to the interior vehicle floor level thereby enabling a handicapped person, on crutches or in a wheelchair, to easily board or disembark from such vehicles at will. The riser element which is pivotally connected to the movable upper step is freely pivotal below the horizontal so as to compensate for uneven ground during the loading operation. The riser is then selectively raised to form a fixed horizontal co-planar extension of the loading platform so as to enlarge the capacity of the loading platform during the actual lifting and lowering operation.
An elongate safety guard plate is pivotally connected to the outer edge of the riser and is normally retracted thereagainst when not in use. After a wheelchair has been moved onto the loading platform, the safety guard plate can be selectively pivotally moved to a raised vertical position along the outer edge of the riser so as to act as a guard against inadvertent movement of a wheelchair or other equipment from the expanded platform while the platform is being raised to the level of the vehicle inside floor or is being lowered to the ground level.

Description

Thls :Lnvell~i.ol~ t-e.la~cs ~0 ~In Jlllpt-OVf!(] ;IlltOlll~lt`lC
lift dev:Lce for use ln assocla~lorl wi.th dol)rway openl.ngs of buildings or of vehi.c.l.es such ~s buse~ and vans so ~s to facilitate the loadi.ng and unlo,~lng of handlcapl)ed persons lnto and out o sucll bu-lldings and/or vehicles.
This applicatlon dlscloses an improvement on the apparatus disclosed in Canadian P~tent No. 1lo82~65~/ issued July 29, 1980, filed November 24, 1978.
More specifical].y, the invention relates to an improved automatic lift device which conslsts of a lift' carriage that is mounted wi~hin the doorway opening so as to be vertically movab].e therein. Movab'le step and riser elements are provided within the lift carriage so as to ;~
form normal upper and lower entrance steps in their retracted :
normal use position. The lift carri.age is selectively movable to a lowered ground level position and a raised interior floor level position while the upper step and riser remain in their retracted normal step position within the lift carriage. The upper step and riser pivotally connected thereto are selectively extendable outwardly and downwardly by self-contained actuating means mounted solely on the base of the lift carriage. Thus actuated, the upper step and riser form a continuous hori~ontal loading platform in association wit'n the fix'ed lower step formed by the base of the lift carriage. Thus formed, the horizontal loading platform can be selectively lowered to the ground or curb level or to any level intermediate thereto. It can be also selectively raised to the interior vehicle floor level thereby enabling a handicapped person, on crutches or in a wheelchair to easily board or disembark from such vehicles at will.
The riser element whlch :Ls pivotally connect to the ' .

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movable upper step is :freely pivotal below the horizont~ so as to compen-sate for uneven ground duxing the loading operation. The riser is then I selectively raised to :Eorm a fi2~ed horizontal co-pla~ar extension o~ the ¦ loading platform so as to enlarge the capacit;y o the loading plateorm during$he actua~ lifting and lowering operation. An elongate safety guard plate is pivotally connected to the outer edge of the riser a~d is normally retracted thereagainst when not in use. After a wheelchair has been moved onto the loading platform, the safe$y guard pla~e ca~ be selectively pivotally moved I to a raised vertical position along the outer edge of the riser so as to act as lQ ¦ a guard against inadvertent movement of a wheelcha:ir or o~her equipment from the e~panded platform while the plat~orm is being raised to $he level of the vehicle inside floor or is being lowered to the grourld level.
It is thus seen that a highly utili$arian automat;c lif~ device for vehicles is provided which consists o~ a vertically movable lift carriage I which is ea~ily mounted within a recess well of a doorway opening. The lift carriage is p~ovided with normal steps which compr~se a :~xed lower step and a movable upper step and riser plvotally connected thereto. :~n its retracted normal use position, the upper step is positioned to the rear OI the lift frame a~d the pivotally connected riser extends vertically downward to the fixed lower step formed by the base ~ the lift carriage. The sa~ety guard plate is pivotally retracted a~ainst the lower portion o~ the vert; cally-oriented riser when not in use.
It is ~us seen that an improved automa~c liit device is provided which includes a li~t carriage which is provided with a normal step structure which czn be selectively converted to a horizontal loaddng plalEorm by an '1 11~Z214 outward and ~oNnward movement ~f the upper step and concurrent upward ¦ movement o~ the riser pivotally connected thereto. During loa~ng operations, the safety g~ard plate remains horizontally re~racted against the riser so that a wheelchair can easily pass thereover while the riser is in its freely s pivotal loading ramp positionO This simplicity of structure alld movement is not found in the devices of the prior ~nown art.
It is fu~her seen that an improved automa~ic lift device is provided wherein the riser is maintained in a fixed horizontal posi~on during ¦
the raising and lowering ~ ~e lift carriage so as to ~orm a co~planar e~tension o~ the lower step and extended upper step, thus fox~i~ng a~
enlarged loading plal:form.
It is ~urther seen that an improved automa~c lif~ device is provided wherein the upper step and riser are provided with ac~ua~ng mealls which are entirely self-contained alld mounted solely upon the base of ~e 1~ lift carriage.
It is further seen that an automatic lift device is provided which includes a lift carriage that can be selectively lowered to ground level or raised to interior ~loor level with the step assembly in its retracted normal use position or selectively extended to orm a loading and unloading platform in connection with the base of the lift carriage.
It is therefore an object ot this inYention to pr~vide an automa~c door lift for doorway openings having a ver~cal movable lffl carriage ~at ca~ be easily installed in the doorway openings o~ huildings and ~ vehicles such as buses alld vans.
1 Another object of this invention is to provide an automatic door I ft having a lift carriaga provided with a movable upper step and nser I!

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,, pivotally connected thereto and selectively extendahle therefrom $o orm a ' I loading platform.
Still another object of this invention is to provide an automatic door liEt which is provided with an upper step and a riser which can be I selectively converted into a loading platEorm which can be lowered to ground level to receive a handicalpped person on crutches or in a wheelchair and which can then be r~used to deliver such person to the interior floor level of the vehiclesO
Yet another object of the invention is to provide an automatic door lift ha~ing a selectively retractable and extendable step structure which utilizes a movable riser to form a hori~ontal e~tension portion of the loading plat~orm and which riser is provided wi~h a sa~ety guard plate which can be selectively actua~ed to form a raised vertically-oriented wheelchair sa~ety guard or stop along the outer edge of the platEorm while the loading platform is moving ver~cally and which is retracted against the riser when it is not in use.
Another object o this invention is to provide a highly utilita~ian impxoved automatic door lift for vehicles which has a minimum o mo~ing components and which in use reql~ires no ancillary components other than l, the existing upper step and riser elements and self-co~ained actual;ing means there~or to convert from the retracted normal step configura~on to the extended loading platform configuration.
The improved automalic lift structure is thus simple in design and ha~ a minimal number of mova~le components in the operation thereoE.
Further, it does not require an~ a~cillary components or extensions in the li I ;
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operation thereof arlfl is provld~d wlth an enlarged li~t plat~orm dl1rin~
the raising and lowerirly of the llft carriage. q~he enlc~r~ed lift platform is provided with a safety guard element along the outer edge thereof.
The lift structures of the prior known art are highly cornplicated~
both in structure and in operational movement. In addition, they utili~e components which are ancillary to the normal step structures in order to provide safety guards incident to the safe opeEation of the lift. Representa-tive examples of such prior art devices are seen in the United States Letters Patent to Thorley 4,027,807, Maroshick 3,913,~97, Abreu ~,02~,387, Pohl 3,984,014, Perkins 4,007,844 and Wark 3,918,596.
Other objects will be apparent to those skilled in the art upon reading the present description, drawings and claims.
In the Drawings Figures 1 through 17 pertain to the embodiment of the Automatic Lift Assembly invention shown and claimed in U.S. Patent No. 4,16~,292 issued August 14, 1979.
Figures 18 through 32 pertain to improvements to the Automatic - Lit Assembly.
Figure 1 is a perspective view of the automatic lift assembly showing the lift assembly in its use position in a vehicle door opening with the upper step and riser retracted into their normal step use position.
Figure 2 is a front elevation view of the substantially U-shaped lift carriage showing the roller means which engage the vertical track means provided along each side of the vehicle door opening.

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, Figure 3 is a perspec~ve view of the au~omatic lift assembly illustrating the step and riser extended to form a loading pla-tform and ramp and showing the li:Et carriage and platform in phantom line lowered to the ground level loading posi~on.
~igure 4 is a perspective view of the automatic lift assembly in its lowered ground level loading position with the riser element in its ¦ upwardly inclined safety guard position~
Figure 5 is a perspec~ve view of the automatic lift assembly with the lift carxiage and loading plat~orm in its raised unloading position level with the interior floor of the vehicle., ¦ Figure 6 is a schematic side elevation view showing ~he step ¦ e~tending actuating linkage means in their retracted position~
Figure 7 is a schematic side elevation view ~ the step e~tending I actuating linkage means illustrating the step a~d riser being progressively ¦ pivotally extended and lowered to form the loading plateorm and ramp,.
~igure 8 is a schematic side elevation ~iew ~ the automatic lift assembly illustrating the lift carriage actuating means and showing $he lift carri~ge in its lowered ground level position, in its intermediate norm~l step position alld in its raised vehicle floor level position.
` Figure 9 is a schematic cross-sectional rear elevation view of the automatic lift assembly taken on line 9-9 o Figure 8 showing the lift carriage sa~ety lock assembly in engagement with the pivot arms o:f the li:Et carriage actua~ng means.
¦ ~igure 10 is a schematic cross-sectional top view of the au~oma~c ¦ lift assembly ~en on line 10-10 of Figure 8 showing the lift carriage and the lift carriage actuating means a,ssociated therewith.

Figure 1] iS a schemcltic bo~om p~r~peCtiV~ Vie~/ Of l:ho ~x~cnded loading platfoxm showing the riser safety guarcl actua~ln~ a~sernbly in its normally rest position.
Figure 12 is a schematic bottom perspective view of the extended loading platform showing the riser safety guard actua-ting assembly in engage-ment to move the riser to its raised safety guard position.
Figure 13 is a schematic flow diagram~showing the hydraulic control system.
Figure 14 is a schematic diagram showing the electrical control circuitry, Figure 15 is a plan view of the actuating control panel for the automatic lift assembly.
Figure 16 is a schematic end view of the lift shield assembly and is located on the first page of drawings with Figures 1 and 2.
Figure 17 is a schematic cross-sectional view of the vertical track assembly and is located on 'he fifth page of drawings with Figures 6 and 7.
Figure 18 is a perspective view of the improved automatic lift asse~bly in its use position in a vehicle door opening with the upper step and riser retracted into their normal step use position and showing the safety guard plate retracted against the lower portion of the riser.
Figure 19 is a perspective view of the improved automatic lift assembly illustrating the step and riser extended to form a loading platform which has been lowered to its ground level loading position with the riser in its lowered freely pivotal loading ramp position and with the safety guard barrier plate still in its retracted position against the riser.
Figure 20 is a perspective view of the improved automatic lift assembly as shown in Figure 19 with the riser in its fixed horizontal ,~ ' .

"111;~214 position forming a co-planar exten.sion crf the loading platform and with the safety guard barrier plate in i-ts raised verically-oriented gllard use ¦ position.
I Figure 21 is a perspective view of the improved automatic lift ¦ assembly with the lift carriage and erJarged loading platform in its raised I unloading position level with the interior floor ~f the vehicle.
F~gure 22 is a schematic side elevation view of the improved li self-contained step extendin~ actuating linkage mealls in their retracted position with the upper step and riser retracted into their normal step use positio~.
Figures 23 through 25 are schema~ic side elevation views o~ the improved step e~ending actua~g linkage means illustrating the step and riser being progressively pivotally extended and lowered to form the loading platform and with the riser in its lowered freely pivotal loading ramp po~ition~
E~gure 26 is a schematic side elevation view oE the improved automatic lift assembly illustrafing the lift carriage actua~dng means and showing the lift carriage in its lowered ground level posi~on, ~n its inter-mediate normal st~p posi~on and in its raised vehicle tloor level position.

2~ Figure 27 is a schematic bottom perspec~ve view o the riser (ra~np) actuating assembly in engagement to move the riser (ramp) into its fixed hori~ontal posi~on as a co-planar extension of the loading ~latform.

~! Figure 27A is a partial ~chema~c view showing the xiser (ramp) ~1 actuating assembly in its retracted position.
, ~gure 28 is a partial schema~c bottom view showing the safety g~rd bar~ er plate ac tuating mec b n~sm in its retracted pos Lhon.

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~lgure 29 iS a par~al schema;~c bottom ~ievv showing safe~r guard barrier plate actua~ng mechanism in i-ts extended position with the sa;fety guard barrier plate in its raised opera~ve use posi~ion.
Figure 30 is a schematic side elevation view showing the sa:fety ,~
guard barrier plate control linkage with the barrier plate in its ra~sed guard position and in phaIltom line in its retracted stored position.
~igure 31 is a schematic flow diagram showing the hydraulic control syste~n.
Figure 32 is a schematic diagram showing the electrical contr~l circuitry.
General Description , ,_._ A~n improved automatic Lift assembly is provided for use in vehicle or building doorways which consists o~ a lift carriage movably positioned within a doorway opening. The lift carria~e has a substalltially U-shaped configura-~on wherein the horizQntal base thereof is adapted to form a lower step portion. A movable upper step is pivotally positioned with the lif~ carriage in a normally retracted stowed step use position above and to the rear of the lower step portion. The upper step is selec~ely ~xtendable forwardly and downwardly so as to form a co-planar platEorm extension ~ the lower step por1ion. A movable riser is provided in pi~otal engagement with the upper step so as to selectively extend vertically down-war~y to the lower step portion when the upper step is in its retracted stowed step use position within the lift carriage. The riser is selec~vely extended upwar~ly and outwardly to form a freely pi~otal loadiIlg ramp extension rom the extended upper step. The improved automatio lift assembly is providecl with sel~-contained upper step alld xiser actuating means which are mounted on the base of the li:~t carriage and whic~h selectively e~tend and retract the upper s-tep and riser without attachment ~ to any ancillary surfaces or structures. Furt~er, the improved automa~c I lift assembly is provided with enlarged carrying platEorm during the lif~
and lowering of the Lift carriage. The enlarged carrying platform is formed by the base of the lift carriage, the extended upper step and the riser which ¦ forms a horizontal co-planar extension of the upper step. In the ear~ier embodiment of the invention, the riser was inclined upwardly during the lif~ng and lowering o~ the lift carriage, thereby decreasing the capacity ~
the carrying platform. A sa~ety guard barrier plate i5 pivotally cormected to the risel along the outer longituclinal edge thereo The barrier sa~e~
guard plate is pivoted flat against th~ riser when not in use and is adapted to be pivoted to a vertical use position when the riser is moved to its horizontal pla~eorm extension use position. The sa~ety guard pla~e acts as a safety guard barrier for wheelchairs alld the like which ha~e been loaded onto the enlarged platform :Eormed by the extended upper step and riser.
Lift carriage actu~1:ing means ars provided to selectively lower the lift carriage to ground level alld to selectively raise the lift carriage to the interior floor level of the building or vehicle. As irl the earlier em~odiment of the invention sh~wn irl Figures 1 through 17, the impro~ed embodimellt .;
o~ the illvention is pr~ided with lift carria~e actu~ting means ~hich include a main pivot act~Ltor shaft positioned behind the lift carriage. The pi~t actuator shaft is provided with a pair of fixed spaced-apart pivot suppol t arms which bracket and are in piv~tal link engagement with the lift carriage.

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~¦ The actuator sha~t is selectively rotatable so as to selec~Yely raise and ,,lower the lift carriage. The main pivot actuator shaft is selectively ¦¦ rotated by a hydraulically-operated steering gear power unit. The steering gear power unit is adapted to translate the linear motion ~f the piston provided therein to rotary motion to drive the main pivot actuator sha~t.
Sa~ety stop assembly mealls are provided in the doorway ope~ng in selective engagement with the pivot support arms so as to support the lift carriage in its intermediate normal use position. The sa~ety stop assembly means are selectively retractable out o~ engagement with the pivot sllpport arms so as to permit selective raising and lowering of the lift ca,rriage.
In the improved embodiment of the invention, riser actuating meaIIs are provided in association with the movable upper step and the pivotally movable riser to select;ively move the riser from its downwardly depending loading ramp position to its fixed horizontal positioll to form co-planar extension ~ the loading plateorm. Sa~ety gllard barrier plate actua~ng means are providsd in association with the riser actuating means to selec-tively pivot the barrier plate to its vertical guard position along ~e outer longitudinal edge of the horizontally extending riser. Control panel acuating means are provided to selectively control the lift carriage actua~ing means, the movable upper step and riser pivotally connected thereto, the safety stop assembly means and the riser and barrier pla~e actua~ng means.
~pecific Description of a Preferred Embodiment I ~
I As sh~wn in Figure 1, the a~ltoma~c lift assembly 11 is mounted ~ in the door opening 12 of the vehicle 13. The automatic lift assembly 11 is z~ :

l~ mounted wi~hin a step well rece~;s 14 pr~vided in the vehicle ~loor 15 and isver~cally mo~able therein. Thus positioned, the automatic lift assembly ll does not interfere with the normal operatio~ ~ the vehicle door lB. The I automatic lift consists of a substan~ally U-shape~ metal lift carriage 17 ¦ which is provided with vertica;lly aligned rol:Lers 18 on each side thereo:f which are adapted to slidably engage vertical track body guides 19 which are mounted along each side OI the door opening~ As shown in Figure 1, l:he base of the lift carriage 17 forms the lower step 20. The improved embodiment oî the mventîon is similarly shown in Figure 18.
As will be hereinafter described, a retractable upper step 21 having a riser 22 pivotally connected thereto is provided withii~ the l~t carriage 17~ The upper step 21 and the xisex 22 are movable with and are selectively e~tendable from the lift carriage 17 so as to form a lo~ding platform extension 23 in combination with the base 20 of the carriage lift 17 as shown in Figures 3 and 4. MGre specifically, the pla~form 23 is formed by pivotally extending and lowering the upper step 21 so that it lies i~ an abuffing co-planar relatiunship with ~e base 20 of the lift carriage 17. The riser 22 is freely pivotal so as to provide a loading ramp e~tension ~o com-pensate for uneven gro~nd to complete the loading platform as shown in Figures 3 and l9o The loading platform 23 is shown in phantom line in Figure 3 in its lowered ground level loa~ng position with the riser 22 in its lowered loading ramp position so as to receive a wheelchair or permi~ an ambulatory person to walk direc1~1y onto the plat:form 23 -Eormed by ~he base 20 a~d the upper step 21. This is also shown in the improved embodiment o i the invention as shown in Figure 19.

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Z~14 In the earli~r ~mbo~liment (>E the inv~nlion as ShOWII in T~ ure ~, the lift carriage 17 and plat~orm 23 ~Is,soci~l;ed th~re~Yitll is shc)wrl in it~3 lowexed ground l~vel lo~ding posi~ion. The riser 2~ is in its raised safet~
gua:rd posi~on which prevents a w~eelchair (not shown) from rolling ~f of ¦ the platEorm while it is being raised or lowered. However, this decreases the effective size of the carrying plaltform.
~ the improved embodiment of the inven~on ~s specifica~ Ly shown in Figures 2~, 21 and 29 the riser 22 is kept at its horizontaL use position, thus increasing the capacity of the carrying platform throughout L0 its li~ng and lowering operation. A sa~ety guard barrier plate 2~a isprovided along the outer longitudinal edge of riser 22. Barrier guard plate actuating means are provided to selectively raise the guard plate 22a to i~s vertical guard position as shown in Figures 20, 21 and 29 or pivot it to its ~ stored xest position against the riser 22 as shown in Figures 18~ 19 and 28.I As shown in Figure 5, the lift carriage 17 is raised so that the platform 23 is at the level of the interiox floor of the vehicle so that the wheelchair or person thereon can be movecl directly into the interior of the vehicle. This is also shown in Figure 21 with respect to the impro~ed embodiment of the invention describecl herein.
eo It should be noted that lift carriage 17 with the retrac~ed step 21 and ~ser 22 in their retracted normal use step position as shown in Figures 1 and 18 can be lowered to ground level so that a person can st~
thereon. The lift carriage can subsequently be raised to permit the user to step or walk into the inteIior of the vehicle as necessary.
!5 ~; ln the automobile lift assembly shown in the ~fore mentioned U.S, Paterlt No. 4,164,292, the step actua~ing, linkage means are : B

" shown in F~igure 6 (step and riser retracted) a~d in F'i~ure 7 (step and riserbeing extended). It is within the scope o~ the inve~ion -to add corresponding ¦i co-acting step actuating linkage means to the other side of the liE~ carriage.
I A step actuating control cylinder 24 is anchored at one end to an anchor I block 25 provided at the top of one of the side panels oE the lift carriage 17and is movable therewith. The control cylinder actuator rod 26 is pivotally ¦! connected to an angular control level 27 which is pivotal about pivot pin 28 prol7ided in the side wall of the lift carriage. Ths angular control lever 27 I is in turn pivotally connected to a first connector link 29 by pin 30. The I first connector link 29 is in turn pivotally connected to the second connector¦ lin~ 32 by pin 31. The second connector link 32 is colmected a~ its other end to ~e first pivotal e~tender arm 34 by pm 33. A third connector link 35 is pivotally connected at one end to pin 33 and at the other end to pin 36 ¦ provided on the second pivotal e~tender arm 37.
l As shown in Figures 22, 23, 24 and 25, the improved automatic lift assembly utilizes a step actuating assembly which is self-contained and mounted solely in operative engagement with the upper step 21 and riser 22 elements and the bottom 20 o~ the lift carriage 17. The improved step actuating assembly pr~vides more posi~ve control of the movable step and riser as ~ey are being selectively e~tended and retracted. The improved step actua~ng assembly further allows for critical pre-assembly and tes~ng of the step and riser assembly before installation in lift carriage 17~ ¦
Further, thereis a cost sa~7ings over the earlier structure as shown in ~I Figures 6 and 7 in thatthe anchor block 25, control lever 27, pivot 28, 1' connector link 29 and second connector link 32 are eliminated. ~s sho~ in 1. i Il 1~ -14-, Figures 21 through 25, the improved ~tep a~tua~ng as~embly consists of hydraulic cylinder 24' which is pivotally co~nected at O}l~ end to the base 20' at pivot 20a and at the other end to cont~ol link 3' ~t pivot 3d b~ cylintler rod swivel 2. The control link 3' is pivotally connected at one end to the base of the lift carriage (lower step~ 20' by pivo~ pin 3~ and at ~ o~her end to the connec~ng link 4~ by pivot pin 3b. The connecting link 4' is pivotally c~nnected to link 32" by pivot pin 3c. It should be noted that lin~s 32t, 32" and 35 are rigidly connected (welded~ t~ether and cannot articulate within that assembly. Further, it shonld be noted the improved step actua~ing assembly (including cylinder 24') is prolrided on each ~ide ~E the step assembly so as to balance the forces required to extend arld retr ct th~?
upper step ~d riser assemblyO The remainder of the improved step actuating assembly is the same as that shown in Figures 6 and 7 and the opera~on thereo is hereinafter described.
The first pivotal extender arm 34 i~ pivotally connected at one end thereof to the upper step 21 by pin 38 and at the other end thereof is ~ edly connected to rod 39 which is provided through the base o:f the carriag~ lift.
~: Rod 39 e~tends through the base of the carriage lift to fixedly engage a cor-respond~ng extender arm 40 positioned on the cpposite side of the ca~r~age lift 17. The extender arm 40 is similarly connected to the opposite end o:E
the upper step 21. The s.ocond pivotal exterlder arm 37 is pivo~lly connected a~ one end thereo~: to the upper step 21 by pin 41 and at ~e other end ~ereof is f;xedly connected to rod 42 which is provided through the base o~ the Il carriage lift. Rod 42 which is spaced apart from and parallel to rod 39, alsoextends through the ba~e of the carriage lift to fixedly engage a corresponding %~L

Il extender arm 43 positioned on the opposite side ~E the carr:Lage l,~. The extender arm 43 is similarly connected to the opposite encl of upper step 21.
The :riser 22 is pivotally connected to upper step 21 at points 44 at each end o~ upper step 21. Cam pins 45 and 46, respec~vely, extend 1¦ outwardly from each end o~ the riser 22. As shown in Flgure 6 and 22, the ¦~ cam pîn 45 engages a cam extension 47 provided on the second ez~ender arm . Il 37 so as to retain the riser in its retracted vertieal position. A simila~ cam e~tension ~not shown) îs provîded on the corresponding e~ender arm 43 sv as to engage cam pîn 46.
As shown in phantom line in Figure 7~ 2Z, 23, 24 alld 25, when the extender arm 37 is pivoted ou~wardly, the end thereof moves into contact with cam pin 45 so as to pivotally move the riser into a slîgh~ly below horizontal loadîng ramp posîtion. The same action occurs on the opposite end of the riser when the end of the extender arm 43 engages cam .
pîn 46.
~ ~pera~on, the step actuating linkage mea~s can be selectively actuated to piv~tally extend the upper step 21 alld rîser ~2 outwardly and downwar~dLy so as to form a co-planar platPorm e~tension 23 ~ the lower . step or base 20 ~ the carriage Lft 17 as shown in Figure 3. ~ the earlîer embodiment o~ the illveni:ion, as shown in Figure ~, ~is is accomplished by actival;on o~ actua1ing cylinder 24 to selec~vely retract piStOll rod 26. The piston rod 26 acts upon the angular control le~er 27 so as to pivot the angular control lever 27 about pivot pin 28. Thus pivoted, the angular control lever 27 acts upon the connector lin~s 29 and 32 so as to pivo~ally move the first and second extender axms 34 and 377 respectively, about the pivot points established by rods 3g and 42. In the improved embodir~lent lll'~Zl~ ~
I of the invention, as shown in ~gures 22 through 2~, the actuating cylinder ! 24' acts directly upon the connecting link 3' to actu~te th~ step mounte~
actuating assembly previously described. The extender arms 34 and 37 move simultaneously because they are connected by co~nector link 35. The corresponding oppositely positioned extender arms 40 and 43 move si~ultaneously because they are fixedly connected to rods 39 a~d 42, respectively. Thus the pivotal movement o~ the extender arms 34, 40 a~d 37, 43 moves the upper step 21 outwardly and downwardly while maintaining its horizont:ally-oriented position. As extender arms 37 are piv~ed towaI d ~eir substantially horizontal e~tended posi~on, they contact cam pins 45 and 46, respectively, so as to pivotally raise the riser 22 to its loading ramp position as shown in Figures 2 and 2~. ~ actuality, the riser 22 is only pivoted to a position which is approximately 30 degrees below horizolltal.
The Iiser 22 is free to pivot upwardly toward a horizontal posi~on as required upon contact with the ground or curb so as to pro~7ide a ramp for rolling a load upon the plat~Eorm 23.
The lift carriage actuating means 48 are shown in Figures 8 through 10 and 26. The li~t carriage assembly is selectively raised or lowered by applying hydraulic pressure to a power unit 49 which consists o~
a double-acting hydraulic pist~n whose linear travel is converted to rotary output through interference mesbed teeth on the piston and on the output shaft~ In the earLier embodiment of the in~enlion, ~he rotary output sha~t 50 is adjustably connected to the main pivot actuator shaft 51 by use of adjustment connector mealls 52 (see ~lgure 9). The adjustment connector ¦ means 52 comprises an elbow connector arm 53 which is fixedly connected to the main pivot actuator shaft 51 ancl which is adapted to engage a collar ~lZZl~
I¦ pin extension 54 prorided on the rotary ou~put sha~t 50. The improved ¦¦ adjustme~t conneetor meanS (not shown) consist~ of a de~ice known ¦ commercially as an air brake slack adjuster replacing elbow connector 53, ¦ and is fixe~lly connected ~o th~ main pivot actuator sha;et 51. The eollar pin~ extension 54 is replaced by a lever commercially known as a pitman arm I and is fixedly connected to the rotary output sha~t 50. A sleeYe colmector ¦ whos~ interior diameters are such as to slidably engage the rot~ry oui:pu~
shaft 50 alld the main pivot actuator shaft 51 is used to maintain shaft centerlines in alignment. A spacer lever is welded to the s~eeve connector to fill the sroid between the pitman arm and the slack adjuster and thP th:ree .
parts are bolted together at ~ome distallce from their respective pivotal center moun~ings~ The improved ad~ustment connector me~s provides a greater adjustment ra~ge to insure th0 lift carriage plati orm height when raised to be equal to the vehicle floor height. Further, there is a cost savings in manufacturillg in ~at precise fixturing of the main actua~or pivot sha~t 51 and M~e lift carriage pivot support arms 56 and 57 al~d indexing o~
the elb~w connector 53 is eliminated. The maill piYo~ actua~or shaft 51 ~xtends parallel to alld behind the rear wall 55 a~ the well recess in which the liit carriage 17 is mounted. A pair o~ spaced-apart lift carriage pivot support axms 56 and 57, respectively, are fixedly attached to the actuator sha;Et 51 a~d are configured to extend into the recess well paraLlel to a~d spaced apart from the exterior surfaces 58 and 59, respectively, o~ the side walls of the lift carriage 17.
Each of the lift carriage pivot arms 56 alld 57, respec~vely, are pivotally connected to one end o~ the connector links 60 by pivot pins 61.

Each connector link 60 is pivotall~r ~mchored to the respec~ve ~ides of the li:ft car~iage by anchor pin 62. As shown in Figure ~ an~l 26, ~he pi~ot arms 5~ and 57 in conjunc~on with their respec~ve conneckor links 60 support the lift carriage 17 in its normal use position A with the recess well. Upon salective actua~ion of the poWer unit 49, the main piVot actua~or sh~t 51 iS
rotated to pivotally raise the pivot arms 56 and 57 egtending there~rom.
This movement raises the connector links 60 with the resultant li~ting of ~e lift carriage 17 to the raised position B as shown in phantom line in Figure 8 and 26. :In this position the base 20 ~f the lift carriage is even with the interior lioox 15 o~ the vehicle.
Upon selec~ve rotation of the main pi~ot actuator sha~t 51 in the opposite direction, the pivot arms 56 and 57 and comlector links 60 are lowered so as to move the li~ carriage 17 to its ground or curb level lowered position C as ~rther shown in pha~tom line in Figures 8 and 26.
Al$hough in Figures 8 alld 26 the lift car~iage 17 is shown with the upper step 21 and riser 22 in their e2~tended platforrn 23 position, it is possible for the lift carriage 17 to be moved to the raised B and lowered C po&i~ons with the upper step 21 and riser 22 remaining in their normal retracted st~ed step position as shown in Figures 1 a~d 18, respect;ively.
As ~hown in Figure 10, the power unit 49 is provided with ~
manual control sha~t 63 alld detachable h~ndle 64 so that the lift carri~ge 17 can be manually raised, lowered and/or re~urned to it~ normal intermedia~e position B in event o failure ~f the regular hydraulic control system.
I It is within the scope o the improved structure that a manual hand pump be provided that will pefform all funchon~ of the lift m event of l~lZ'~14 an electrical failure. The unit will re~uire a six~way ma~lua;l co~trol valve to direct the oil to the proper circuits trom ~he pump.
As shown in Figure 9 (and as con~nued in the improved automa~ic lift assembly), a selectively actuated sa~ety stop assembly 65 is provided to support the lift carriage 17 in its normal s$ep height position B within the recess well. A solenoid actuator cylinder 66 is provided in engagement ¦ with a pivotal control link 67 which is connected to actuator connector links I ;-68 and 69 at each end thereof. The actuator connector links 68 and 69 are I provided with s~e~y slide blocks 70 and 71, respecti~ely, which are adapted I to supportably engage Eixed support blocks 72 alld 73 provided on the pivot arms 56 and 57, resp~c~Lvely, while the lift carriage 17 is in its normal step height position B. Prior to lowering the lif~ carriage 17 to its lowerecl posil:ion C, ~e actuator cylinder 66 is actuated so as to retract the slide blocks 70 alld 71 out of contact with fi~ed support blocks 72 a~ld 73, 1~ respectively. This permits the pivot arms 56 and 57 to be lo~ered as desired. ~ prac~ce, ~e pivot arms 56 and 57, and hence the lift carriage 1 7, are raised slightly so as to release the load on the safety slide blocks 70 and 71, thus permifflng the cylinder 66 to easily retract them. This feature tests the integrity of both the electrical and hydraul~c systems be~ore allowing the lift to be deployed.
The safet~ slide blocks 70 and 71 are spring biased to return to their normal support interference position in alignment with the fixed support blocks 72 and 73 after the liIt carriage L7 has been lowered.
After the pivot ax~ns 56 and 57 are lowered, the spxing biased slide blocks 70 and 71 move outwardly back into their normal support position~ Both the fixed support blocks 72 and 73 and their respective slide ~ Z2~
blocks 70 and 7~ are correspondingl~7 tapered so tha~ the :~:ixed support blocks 72 and 73 easily displace and move pas-t the sa~etD s:Lide blocks 70 ¦ ~d 71 as ~e pivot arms 56 a~d 57 pivot upwardly to move the lift carri~ge I i7 into its raised position B as shown in Figure 8.
Th~rea~ter, when the pivot arms 56 aDd 57 mov~ downwardly to return the lift carriage 17 to its normal rest posi~on A, the :ïxed suppo.rt blocks 72 a~d 73 come to res~ upon the slide blocks 70 and 71 so as to support the lift carriage 17 in position A. This is shown in ~iqgure 9 a~d in phantom line in Figure 8. It is within the scope of the inven1ion to pr~ide f~r selec~ve mecha~ical, rather than solenoid, actuated retrac~on o~ the slide blocks 70 a~d 71. :~n addition, in another embodiment Oa the invention ~e lin~age controlled slide blocks are provided on the pivot arms 56 and 57 and the fi~ed support blocks are correspondingly mounted on the side walls of the recess well (not show~ This mechaIlical stop feature which is also ~5 inco~porated into the improved embodiment of the in~rention insures that there would be no "hydraulic drift" o~ the lift downward? thus preven~ng damage to the li:Et or suddenly actuating the vehicle brakes because a~
interlock switch detected the lift ou~ ~ posi~on.
In the earlier embodiment of the inven~on, as shown in Figure~
11 and 12, a riser saPet:y guard actua~ng assembly 74 is prov~ded so as to selectively raise t~e riser 22 to a raised sa~ety st~p position ~ abou~ 30 to 35 degrees above ~e horizontal as sho~m in Figures 4, 5, 8 and 12. ~ ~is raised posit:ion, the riser 22 prevents a wheelchair or the like from rolling off of the lift carriage 17 onto the ground. The riser safe~y guard actu~ting asse y 74 consists ~ a hydr- tuating ylinder 75 which acts on 1l~ pivotally connected actuating links 76 and 77, The actuatingr links 7~ and 77 ¦¦ in turn act upon a slidable push rod 78 w~ich selectively slides under the fixed lift rod 79 pro~rided on the riser 2~ so as to pivo~ally raise the riser Il 22 to its raised inclined sa~el;y stop position. The pivotal Links 76 and 77 are I
I biased by spring 80 so as to retract the slidable push rod 76 when ~e actualing cyli qder 75 ii not exerhng pres:~ure against the links 76 and 77.
spring 81 retains the slidable push rod ~8 within its guide supports 82 and 83. The guide supports 82 and 83 are slotted so as to permit side clearance movement of the push rod 78 i~ the riser ellcounter~ an o~stacle a~d ~
fixed push rod 79 cannot move in response to pressure from ~e actuating cylinder 75. As shown in Figures 11 and 12, ~e actua~ng cylinder 75, t;he pivotal links 76 and 77, ~e slidable push rod 78, ~e guide supports 82 a~d 83 and springs ûO are posffloned beneath the ~pper step 21 and are movable therewi1~h. The fi~ed lift l:od 7~ is positioned ~n the Imderside of the riser 22 in direct alignment with the slide push rod 78. A growld rest member 84 is provided 031 the bottom side of the upper step 21 as shown in Figures 11 alld 12.
~ the improved embodiment of the au~oma~c lift invention as sh~wn in Figures 27 through 30, a riser and sa~el~r guard barrier plate 2Q actuating assembly 74~ is provided so as to selectively raise th~ riser 22 from its free ramp position to a raised substalltially horizorltal position to form the outer co-planar extension of the loading platform. The improYe~
iser alld sa~ety guard ba:rrier plate actuai;ing assembly consists of a pa~r of opposed hydraulic actuating cylinders 75' which act upon a pair ~
1¦ spaced-apa~t opposed actuating links 76' and 77'. Each pair a~ actua~ng ~lZZ14 . links 76' and 77' in turn act UpOIl sliclable push rods 7~' which selec~ivel~r slide under :fixed li~t rods 79' provided on the riser 22 so as to pivo~lly raise the riser 22 to its raised horizontal position to form an extension of the loading platform in cooperation with the upper and lower steps. The pivotal links 76' and 77' are biased by springs 80 so as to retract the slidable push rods 78' when the actuating cylinders 75' is retracted and not exerting pressure on the links 76' and 77', as shown in Figure 27A.
The safety guard barrier plate actuating assembly is shown in Figures 27, 27A, 28, 29 a~d 30. At the e~treme outward stroke o~ ~e push bars 78', the push bars 78' contact each o~ their respective sa~ety guard barrier plate actuating links 8' which is pivotally cormected to its respec~ve lift rod 79' at pivot 10~ ~ response to such contact, each barrier plate actuating link 87 pivots about pivot 10 to actuate connecting link 9' which i~
pivotally connected at one end to the actuating link 8r and at the o~er end to the barrier plate 11' so as to raise the barrier plate 11' to its r~ised vertical guard position, as shown i n Figure 29. The barrier pl~te 11' is pivotally connected to the riser (ramp) 22 along the outer longitudinal edge thereof at pivot lla. A spring 12' retracts links 8' and 9' when the push bar 78' is retracted a~d is not exerting pressure on link 8', thus sto~ing the barrier plate 117 in its stored position agains~ the riser (ramp) 22 as shown specifically in Figure 28.
It should be no~ed that the improved automatic lift assembly is provided with duplicate spaced~apart riser (ramp) and safety guard barrier ~ plate actuating a~ssemblies which are posi~oned proximate to each end o~ the I barrier plate ~nd riser and eq7l~distant :trom the centerline of the upper step ~LliZ'~L4 ' Th~ improved rise:r an~l saf~ty guard b~rrier plaLe actuatin~
assembly is an improvem~nt ov~r the ~arlicr ~pp,l~atu~ d~,Ycribe~l and claimed in the a~re-me~ 7~d u.S. 'Pat~nl~ No. ~,36~ 92 (F~i~ures 1-17) in that when the riser 22 is activated from its downward r~mp position it ,.
becomes a co-planar horizontal extension c~f the lower step 20 ~nd the upper step 21, thus extending the useful length o~ the resull~ng lift platform to better accommodate a wider variety of devices for the handicapped. The riser 22 is no longer inclined upwardly to perform a safety guard function, but remains in its horizontal position so as to increase the ca~acity o~ the ~1~ c~rrying platform while the lift carriage is being raised and lowered. The sa~ety guard barrier plate 11', located alon~ the outer long~tudinal edge ~f the ~ser 22,is activated automatically to its raised vertical safety guard position when the riser is moved to its horizontal position and acts to pre~rent the wheeled equipment ~rom rolling of~ the carrying platEorm. The safety guard barrier plate actuating linkage is so designed that when the barrier plate is in its vertical use posi~on, the restricl:in~ linkage i5 in tension and pivot centerline alignment, and therefore not subject to undesired over-travel or compression collapse of components.
A movable step shield pa~el assembly is provided in association with the li~t carriage 17 so as to provide an enclosed continuation of the recess well when the lift carriage is moved to its lowered ground posi~on C
as shown in Figure ~. The step shield panel 85 moves w~th the lift carriage 17 and acts as a safety shield to protect the legs of a person riding on the lift carriage from contact with the vehicle body and associated actuating 'S structures positioned behind the safety shield panel 85. As shown in Figure 16, one embodimerlt of the step shield panel assembly consists o:~ a ~B . ,.
.

Z~4 vertically-oriented panel 85 which extends across the rear open portion ~f the U-shaped lift carriage 17. An elongate horizontal flal1ge 86 is provided along the lower edge o~ the step shield panel 85. Guide members 87 are l; provided on the rear su~ace of the step shield 8~ which slidably engage - 5 channels 88 provided along the rear wall o~ the recess well. Retaining springs 89 engage the rear portion of the fl~ge 86 s~ as to retain the shield in its normally up stowed position. As the U-shaped lift carriage 1l is moved to its lowered ground position C, ~e lower po~on of the lift carriage 17 moves against the ~lange B6 to draw the shield panel 85 down-wardly therewith. As the lift carriage 17 moves upwardly, the action o~ the spring 89 returns ~he step shield panel 85 to its stowed position with the rear portion ~ the flange 86 dr~wn against the lower edge of the rear wall of the recess well. It is within the scope of the invention to use alternate means of enabling the step shield panel to co-act with the lift carriage in the foregdng manner~ The foregoing step shield panel assembly iB
incorporated into the improved lift assembly described herein~
A schematic Elow diagram of the hydraulic system o~ the earlier embodiment of the inven1:ion is shown in ~igure 13. The hydraulic system for the improved automatic lift assembly is shown in Figure 31. The electrical diagram is shawn in Figure 32. A pump alld reservoir 90 is provided with push button controls 99 and 100 (see Figure 32) to actuate the step control c~linder 24' a~d lift carriage power unit ~9, respec~vely.
Solenoid actuated ~low control valves 93a and 93b are pro~ided to selecl:ively actuate the riser safe~r guard cylinder 75. It is within the scope of the invention to alter the hydraulic control system as desired as long as the same overall ~pera~on of automatic lift assembly remains the same. The lift assembly can be powered by a separate 12-volt electric motor driven L~l~Z~4 ¦ hydraulic pump and reservoir assembly (commonly called a "power pacls") ¦ or call be $apped o~f frorn the support:ing vehicle's power steering sys~em.
Control oE the lift ~ ction is by a push button or rocker switch actuating the solenoid cartr~Ldge valves o:l conventional design mounted in the pump unit. Switch positions are ~up ~ or ~down~, and are the momentary contact type requirin~ pressure on the svvitch until the desired lift function is completed.
Control of the step operation is also by push button or rocker switch actuating the solenoid cartridge valves of convention design mounted in the pump lmit. Switch positions are 'qn" or "out" and are the momentary contact ~pe requiring pressure on the switch until the desired step :Eunction is completed. The corltrol switches can be mounted in the vehicle dash pallel, in a control bo2~ on the end ~ an electrical cable or ally other position and local:ion desired.
As stated previously, the lift assembly is raised and lowered by a power unit 49 commonly called a steering gear. Within the steexing gear is a hydraulic cylinder in which the piston is hydraulically powered to either end ~ the cylinder. The piston's linear tra~el is trarls:Eormed to rotary motion o~ the output shaft 50 by interference meshed teeth on ~e piston mating with teeth on the rotary output sha~t. Ma~imum ro~ry nnotion of ~e output shaft 50 is generally 90 degrees.
As stated previously, the rotary output shaft 50 ~ the power unit 49 is securely engaged to the main pivot actuator shaft 51. The actuator sha~t 51 is mounted to the step well and the piYot support arms 56 and 57 are fixecUy secured thereto. ~otation of the shaft 51 moves the pivot support arms 56 and 57 up OlL down which act through co~necti~ li~iks 60 ! -2~-11 , ................................ .

l~ Z~4 so as to correspondingly move the lift carriage 17~ The power unit 49 includes a hydraulically operated piston. Power is applied in both up a~d down modes with a pressure relief ~alve limiting the force inthe down function. Prior art devices have used linear actuators (hydraulic cylinders) to move arms in the manner described above which at some point leaves the piston rod exposed to the elements. Since the piston rod is the seal su~face required to prevent the hydr~lic -fluid from leaking from th0 actuator cylinder, if the rod becomes pitted or nicked, it spoils the seal and the unit is disabled. The use of a power u~it (steering gear) as described above has many advantages. (~ne~ it is sealed to sur~rive in the hostile elements found underneath a vehicle. Two, it has no exposed piston rodO
Three, it is a highly reliable product, mamlfactuxed in large quaIl~ties, and service parts readily aYailable if needed9 Four, it has a mechanical rotary input that, when turned manually, axially displaces the hydraulic piston, turning the rotary output shat and thus man~lly moving the lift up ox down as desired. Howe~er, it is within the scope o the invention to use hydraulic cylinders in place o~ a steering gear i~ desired.
- Molrement ~ the steps is accomplished by using a double acting hydraulic cyLinder ~ conventional design pushing or pulling linkage to extend OI` retract the folding step, and is controlled by a single valYe as described above. There is no interconnec~on with the step and lift hydraulics, except that they share a common hydraulic power source and reservoir.
Movement o~ the riser 22 to the raised horizontal platform position is through double acting hydraulic cylinders 75 pushing link~e to displace the riser to appro~imately the horizontal plane of the lift plat~orm Il , , .

i and actuate the saEety guard barrier plate. The hydraulic :f:luid power is ¦ d~rected ~o these cylinders whenever there is pressure on the 7'lift" or t'up" side of the power unit piston., and is there:fore controlled by the li:Et function control valve. A spring 80 re-tracts the power cylinder and a~tendant linkage when it can overcome the hydraulic pressure~
Placed within the hydraulic circuit between the ~qift~t or 'tup"
side o~ ~e power unit piston and the riser control cylinder is an electro-magnetic solenoid control valve 93a ~at is described as a three-w~y, two position normally closed valve of con~entional design. Properly controlled, i$s fullction is to prevent hydraulic pressure from reaching ~e riser control cylinder when the steps and riser are stowed, aIld/or to release the hydraulic pressure already appli~d to the ramp/riser cylinder to e~pedite movement of persons or equipment over the lowered ramp/riser.
Placed within the hydraulic circuit between the ste~ "in" control valve and ~he operating cylinder~ for the step i5 a second electromagnetic solenoid control valve 93b that is described as a three-way, two posi~on normally open valve of conven~on design. Prjoperly controlled, its funclion is to release hydraulic pressure from the opposite end o~ the riser control cylinders 75' when raising the riser~ and to apply pressure to the riser control cylinders 75' and step in cylinder 24' which share a common circuit to power "downl' the riser and sa~ety guard barrier plate before the steps a;re retracted and stored.
It is witl~n the scope o~ the invention lto apply a separate and independent power source to raise and lower the riser and sa~ety guard 2~ 1 barrier plate as long as the overall opera~ion o~ the riser alld sa~ety guard ~ .

-~8-barrier pla~e is the same~ Placed with:in the hydraulic circ~ît beh~7een the lift up control ~alve and up side of the power unit piston ancl preferably located as close as possible ko the power unit is a pilot operated check val~e of conventional design, whose function is to stop the ~ow (IE oil out oi the power unit in the event o hydraulic lîne failure in the up function. This valve would prevent uncontrolled descent of the lift carriage if failul e occursas described above.
A schematic diagram o~ the electrical control circl~it is shown in Figure 320 A stalldard 12-volt ba~tery 94 is utilized to power the circuit.
A pump motor 95 is controlled by a pump motox control solenoid 96. A lift stop soleno;d 97 a~d two riser contr~ solenoids 93a and 93b are provi~ed to actuate ~e lift stop actuating assembly and the riser sa~ety guard barrier plate, respect;ively.
A step control valve switch 99, a lif$ carriage control val~re switch 100, a riser o~rer-ride switch 101, a riser control switch 102 ~nd a push-button li~ carriage safety stop solenoid switch 103 are provided to pe~Eorm their respec~ve func~ons as discussed herein. ~ addition, a master power on-of~ switch 10~ d a door interlock control switch 105 are illcorporated ~to the circuitry. The door interlock control sw3tch 105 2û preverlts operation ~E ~e Lift carriage when the vehicle doors are closed.
As shown in Figure 15, a control panel 106 is provided near the ~rehicle operator's station so as to permit operation o~ the automa~c lift assembly by the driver of the vehicle.
¦ One em~odiment of the vertical track body guides 19 is shown in ~ Figure 17 and is incorporated into the improved embodiment o:E the invention.

~llZZ:~L4 As stated previously, -the ver~cal bocly guides 19 are mol~ted verlical:ly , along each.side of the door opening. The ver~cal body gwde 19 consist~ o~
1~ a channel member which has side walls 107 which are slanted Lnwardly so as ¦. to retentively engage the g:rooved portion of each of the rolle:rs 18~ The r~llers 18 are mounted in spaced-apart vertically alignecl positions within verl ically-oriented channels 108 provided on each side wall of the lift carriage 17. As shown in Figure 17, the lift carriage mounted channels l~
are in parallel spaced-apart alignment with the vertical body guides 19 so that the rollers 18 extend into operative engagement wi~ the ends of the ¦ sidewalls 107 of the vertical body guides 19. Thus positioned, the rollers 18 ¦ are in slidable engagement with the ver~cal g~des 19. The rollers 18 ¦ selectiYely mo~re up ~d down within the body guides 19 as the lift carriage 17 is selectively moved from its intermediate normal step posi~on down-wardly to its lowered ground level position and~or upwardly to its raised interior floor level position. The unique slidable retentive engagement a~
the rollers 18 within the v4rtical guides 19 provides for greater stability in the veffical movement of the lift carriage 17 wi$hin the door opening.
It is thus seen $hat an improsTed automatic lift del~ice for use in doorway openings of buildings or of vehicles is provided which is versatile and sa~e in operation alld which is not co~plicated in design. The rela~ive simplicit;y of the structure results in ease ~ manufacture, installation and maintenance with-resultant sa~ings in costs. The versatility of the ins~t automatic l;ft device permits selective manual operation o the unit in ~e ¦ event o~ failure o~ the hydraulic and~or electrical systems associa~ed 2~ ¦~ therewith. This feature is of great importance in that the automatic lift li device is used by handicapped persons who col~d no~ cope physica;lly or emo'donally wil:h such failures.

-3 ~ z~ :
It is also seen that this improvement pxovides a unita*y seLe- I
contained upper step, riser and sa-fety guard assembly ancl actuating apparatus whereby the opera~on there~ can be tested beIore installation into the lift carriage.
Further, this improved structure utilizes a ~is,Dr which rsmains in its horizontal use position to form an extended pla~orm having an enlarged carrying capacity during the vertical operation of the lift carriage.
The incorporation of the sa~ety guard barrier pl~te, which is automa~cally actuated when the riser (ramp) is moved to its horizontal use posilion, eliminates the need for the riser to be inclined ver~cally to pe~form a sa~ety guard funcl:ion. This adds greater versatility to the unit due to the increased capacity ,s~f the improved automatic lift assembly From this presentation of an opera~ve embodime,nt of my inven~on, impro~ements, modifications and substitutions will become apparent to those skilled in the art. Such improvements, modifications ar~d substitutions are intended to be included within the spirit of the invention limited only by the sc,~pe oî the hereina~ter appended claims.

Claims

I Claim:

In an improved automatic lift assembly for use in vehicle or building doorways comprising:
a lift carriage movably positioned within a doorway opening, said lift carriage having a substantially U-shaped configuration wherein the base of the lift carriage is adapted to form a lower step portion;
a movable upper step pivotally positioned within said lift carriage in a normally retracted stowed step use position above and to the rear of said lower step portion, said upper step selectively extendable forwardly and downwardly so as to form a co-planar platform extension of said lower step portion;
a movable riser provided in pivotal engagement with said upper step so as to selectively extend downwardly to said lower step portion when said upper step is in its retracted stowed step use position within the lift carriage, said riser selectively extendable upwardly and outwardly to form a loading ramp extension from said extended upper step;
upper step and riser actuating means to selectively extend said upper step forwardly and downwardly so as to form a co-planar platform extension of said lower step portion and to selectively pivotally extend said riser upwardly and outwardly to form a loading ramp extension from said extended upper step;
lift carriage actuating means to selectively lower said lift carriage to a lowered ground level position and to selectively raise said lift carriage to a raised interior floor level position;

a safety guard barrier plate provided in pivotal engagement with said movable riser, said safety guard barrier plate adapted to storably retract against said riser along the outer longitudinal edge portion thereof, said safety guard barrier plate selectively extendable to a substantially vertical safety guard position along the outer longitudinal edge of said riser when said riser is actuated to form a horizontal co-planar platform extension of said lower step and movable extended upper step; and riser and safety barrier guard plate actuating means in association with said riser and said barrier guard plate so as to automatical-ly raise said safety guard barrier plate to its vertical safety guard position while moving said riser to form a horizontal co-planar extension of said said lower and upper steps.

In the automatic lift assembly of Claim 1 wherein said upper step and riser actuating means comprise a self-contained unitary linkage actuating assembly in association with said base of said lift carriage whereby said movable step and riser can be selectively extended and retracted without contact with ancillary support structures.

In the automatic lift assembly of Claim 2 wherein the said upper step and riser actuating means include at least one actuating cylinder positioned at one side of the said movable upper step and riser, said actuating cylinder pivotally connected at one end to said base of said lift carriage, said actuating cylinder pivotally connected at the other end thereof to self-contained unitary actuating linkage provided in association solely with said movable upper step and riser.