CA2108479A1 - Method and apparatus for controlling height adjustable work station - Google Patents

Abstract

A work station, particularly for supporting a computer, having separate front and back tops (27, 46) having separate powered drive arrangements (51) for permitting independently height adjustment. The drive arrangement includes a separate drive motor (68) associated with each top, with the motors being controlled by a controller (91), such as a microprocessor (115). The controller is preferably controlled by an operator using a portable keypad control (92) which can be positioned on one the tops. The controller (91) can be programmed by the operator to permit storage of a number of predetermined height locations each defining distinct heights for both tops (27, 46).

Description

W092/t~33 2 1 0 8 ~ 7 3 Pcr/u~g~ s METHOD OF CONTROLLING HEIGHT ADJUSTABLE
. ~
WORK STATION

FIELD OF T~E INVENTION
This invention relatés to:a height-adjustable table or work station:and, in particular, to an improved automa~ed tab~le;work station havins indepen-dently height-adjustable~front and rear tops which an~respeGtlvely~ support:~the~key~oa~d and screen of a computer, an~ the:method ~f use thereo~.
BACKGROUND:OF:THE INVENTIO~ :
Numerous~;cammercially~availablé~tabl~es have been devel`oped~spec1flcally~for use~ln:~support:lng smalI .
O ~ ~omputers,~;includ:ing~tables~which~employ se~a~a~te hei:~ht-adjustable~ ~:eront ~and ~r ar~table~t~Ds~ for` ` :~
suppor~ing~di~f~erént par~s~ of~the~computer,~`such~as he~ v~c_~d:~o~:thc~ on_ ~-2~1~ to~ an~:the sc~e :moni~or on the~:rear ~:able~:top. These known tables conventlonally~employ--a;~mechanlcal~siruc~ur~ which pe~ s:e2c~:0f~the`~on~ anc rQ~ ~2ble ~vp~s ~ ~
manually height-ad~uste:d.: Suc~mechanica~ s~ructure ~:; ; . tvpically involves~relea able h:eigh~-ad~us.ing s~ops Y~or:manu~lly-actu~a~ted gear mechanisms:employing cr~ve 20 : transmitting rods~(such:-as a flexible shaft) fo_ ransmitting torque to~ mechanisms located adjacen~ ~
oi:~osite ends of ~the tab}e. ~ther known tables emp~lov~ powered drivers, such zs e~_c-r~_ ~o~ors, ~u=

8~o8~7~ ~
WO92/1 PCr~U~91/~9815 . ~ , . .
generally a singIe motor is provided ~or each height-adjustable ta~le top, with the motor being joined to adju~ting mechanism disposed adjacent opposite ends ~f the table through a drive transmitting sha~t (conventionally a flexible shaft) which extends . .
trans~ersely throughout the length of the table.
While these known arrangements hence ha~e provided the ability to independently adjust the height of the table, including adjustiny the heights of the front and rear table tops independently of one another, nevertheless the known height adjusting mechanism have txaditionally been rather complex mechanical structures which have made adjusting the height more difficult than desired. It has also been observed that while such height adjustment may be performed during the initial set-up of the table and of the computer thereon, nevertheless the table is seldomly adjusted thereafter, since such tables are not ~: readily suitable for encouraging rapid and fre~uent ad~us~tment in the table top heights so as to either acco~modate different opera~ors or to encourage the ;~ operator to frequently adopt di~ferent working positions .
Accordingly, :it~is an object of the presen~
invention to prduide an improved table or work . .. ~ , - ~ .
station, par~icularly for supporting a computer, with greatly improved:he1ght-adjusting capabilit~ies so as ~ overcome the disadvantages associated -.iith known tables:~of this general type.
More specifically, hè improved table of this invention preferably includes separate and independPntly height-adjustable front and back table tops each having separate powered drive arrangements for permitting fast and efficient height adjustment of either table top independently of-the other. The drive arrangement preferably includes a separate driv2 ..~0~0- means asscciated -wi_;~ each .o~

W~92/18~33 2 ~ 0 8 4 7 9 PCTJUsg1/Og8l5 motor means of the two tops being connected to and controlled by a common controller, such as a micro-processor. The controller in turn is pref~rably controlled by an operator using a small and portable pendant-type keypad control whi~h can be selec~i~ely positioned as desired, such as on one of the tops~
In the improved t~ble of the present invention, as aforesaid, the controller can preferably be programmed by the operator through the control to permit storage of a number of predetermined table height locations, with each such location involving a predet~rmined and distinct height ~or each of the front and rear table tops. The controller also preferably permits a plurality of table events to be programmed as a sequence, with each event being defined by one of the predetermined table height locations in conjunctlon with a predetermined time interval during which the table tops will be main-tained at the predetermined height location. The controller and th2~programming therPf~r pexmits the t~ble tops to be automatically sequenced from one table event to the next event so as ~o facili~ate and yet substantially mandate desired changes in ta~le height position.: The change from one event to the next event is ~nnounced to the operator by ~isual and/or audible prompts, and movement to the next table event occurs only when the operator inputs an ~ctivating signal.: ~
The improved table of~the presen~ invention, as aforesaid, preferabl~ includes means associated with the motor and the controller, for providing a visual readout as ~o:the actual height of each table top so as to facilitate proper positioning of the tops at desired heights and/or relocating of the tops at other heights. The`controller is capable of deter-mining the existing table height and of driving the tables tO new table heights, such as in response tO

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WO92/18033 PCT/US~1/09815~
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an instruction to move to a predetermined table loca-tion as previously programmed into the controll~r.
The improved table of khe present invention, as aforesaid, preferably incorporates a pair of drive motors associated with each table top, namely rig~t..
and left drive motors associated with the respective right and left support legs or pedestals of the table top. Thé pair of drive motors are pre~erably small low-voltage DC motors to eliminate complex electrical and/or mechanical connections between the right and left pedestals. The controller includes means for synchronizing the driving of the two motors so as to maintain the table top substantially level at all times. Each motor of the pair preferably has a brake and signal generating arrangement associated there-with, ~oth coupled to and controlled from the controller. The brake prevents accidental or load-induced downward driving of the table top, and the signal generator s nds signals to a count~r which is part o~ the controller to permit storing, program-ming, and r~calling~of predetermined table height locations.
Other objects and purposes of ~he~invention will ~ be apparent upon rea:ding~ the following specification ;: and inspecting t~e accompanying drawings.
~BRIEF D S~RIPTION OF ~HE DRAWINGS
Figùre~ I is a perspe~tive view of the lmproved table a~rangement ~accordLng to ~he present invention.
Figure 2 is a front elavational view thereof.
Figure 3 i5 an end elevational view taken substantially along line 3-3 in Figure 2.
~ .
Figure 4 is an enlarged, fragmentary sectional view of the power-driven extendible pedèstal or post arrangem~ent for the table top.
~: ~ Figure 5 is a fragmentary sectional view taken substant~ially along l ine 5-5 in Figure 4.

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. ~ WO92/18~33 2 ~ 0 8 4 7 9 PCT/US91/09815 Figure 6 is a fragmentary sectional view taken substantially along line ~-~ in Figure 5.
Figure 7 schematically shows circuitry for the table controller.
Figure 8 is a top ~iew of a preferred pendant-type keypad control ~or the controller.
Figure g diagrammatically illustrates, on an enlarged scale, the readout or screen associated wi~h the control of Figure 8.
Figure lO is a ~i~w similar to Figure 8 but illustrating a modiied pendant type keypad control.
Figures lI(A) and ll(B) are flow charts which illustrates th~ programming of the controller and the operating of the table arrangement thereby.
Certain terminology will be used in the following description ~or convenience in reference only, and will not be limiting. For example, the words "upwardly'l, "downwardly", "rightwaxdly" and "leftwardly" will re~er to directions in ~he drawings to which reference is made, and will also refer to the same directions as percei~ed by a:keyboard opera~or who is s~a~ding or sitting in front of the table arrangemen~.: The words "front" and ~'rear" will ~: ~e u~ed to denote the portions of the ~able arrange-ment which are respectively closest to and furthest away from the operator, with the front and baek sidés of the table arrangem nt being respectively posi-: tioned more closely adjacent the respective le~t nd right sides in both`of Fig~res 1 and 3. The words :"inwardly" and "outwardl~" will refer to directions toward and away from, respectively, the geometric : center of the table arrangement and designated parts thereof. Said terminology will include the words specifi~ally mentioned, deri~atives thereof, and wvrds of similar import.

WO g2/18033 2 ~ û 8 ~ 7 9 PCr/lJ~91/09815 -~

DETAIT~D DESCRIPTION
Referring to Figures 1-3,~j.there is illustrated a table or work station arrangement 10 according to the present invention, which arrangement includes a base as~embly 11 having respective front and back top ~
assemblies 12 and 13 mounted thereon for independent height adjustment, as exp}ained hereinafter.
The base assembly 11 includes a pair of generally parallel and horizontally elongate legs 15 which are disposed adjacent opposite side edges of the table arrangement so as to extend generally in .
the ~ront-to-back direction. The~e legs 15 each bear dire~tly on a support surface such as a floor, and include a horizontally elongate center housing 16 having a pair of elongate leg elements 17 fixed to and projPcting outwardly from opposite ends thereof.
Each leg 15 has a pedestal structure 18 fixed to and projecting vertically upwardly from the center housing 16, where~y the pedestal structures 18 prsject vertically upwardly in generally parallel relationship adjacen~ opposite sides (i.e. en~s) of the table arrangement. Each pedestal structure 18 includes a pair of outer legs 19 tFigure 3) which are ~ixed to the center housing 16 adjacent opposite ends : thereof and project vertically upwardly in parallel relationship.. The pair of legs 19 as associated with the~ ~ame pedestal structure lB are sp2ced apart in the front-~o-back direction so that the front leg 19 : is associated wlth solely the front top assembly 12, whereas~the rear leg 19 is associated with solely the rear top assembly 13. Each of the outer legs l9 is preferably constructed as a hollow tube and define .therein a vertically elongate inner opening which opens ou~wardly t~rough the upper end OI the respec-tive leg. Each pedestal 18 is vertically enclosed by a removable two-piëce tubular sheath 22 which is :; horizontally elongate in cross section and extends -- WO92/18033 2 1 0 8 ~ 7 9 PCT/US91/09815 between and around the outer sides of the legs 19 so as to enclose same. This sheath 22 hence defines therein, be~ween the legs 19, a narrow compartment 23 having a sideward width which substantially corres-ponds to the diameter of the legs 19. The upper ~nds of the adjacent pair of outer legs 19 are rigidly joined together by a removable top cap 21, which cap closes off the upper end o~ the compartment 23.
The base assembly 11 also includes a cross beam 24 which extends horizontally between and has opposite ends thereof fixedly joined to the upright pedestal structures 1~ in the vicinity of the upper ends thereof. This cros.~ beam 24 is preferably of a hollow tubular cross ~ction so as to de~ine an open-ing 25 extending kherethrough for communication with the compartments 23 defined in the pedestals. The cross beam 24 has flanges 26 at opposite ends thereof which is fixedly attached, as by bolts, to additional flanges fixed to the outer legs 19.
Considering:now the front top assembly 12, it ~:~ inc~ludes a platelike top 27:which de~ines thereon a pl~nar and substan~ially horizontalIy enlarged upper - ~ surface 28 adapted~for use ~a~ a worksurface, su~h as : for supporting a:a~mputer~eyboard. This front top 27 is~:defined~between generally parallel front and : rear edges 31 and 32,:respectively, which extend ; ~ between generally~parallel right and left end or side edges 33 and 34,~ rsspectively. ~:
: A pair of substantially tubular support hubs 35 are fixedly secured to and projec~ing downwardly from ! i the underside of the~front top 27 in the vicinity of the rear corners~thereof. A horizontally elongate . sypport arm 36: is fixed to and proj`ects:forwardly ~: from each support hu~ 35, which support arm 36 is in contact with and:fixedly secured to the underside of the front top Z7:so as~o provide a cantilevered support therefcr. Each of the support hubs 35 has wo 9~1l0~ 8 4 7 ~ PCT/US91/~98l5 the upper end of a vPrtically elongate inner tubular leg 37 fixedly secured there~o, which inner leg 37 projects downwardly in canti~evered relationship for telescopic engagement wi~in a respective one o~ the outer legs 19. For this purpose the top cap 21 has an opening 38 therethrough which is surrounded by an annular bearing or bushing portion 39 formed intPgrally with the top cap, whereby the bearing portion 39 is disposed within the upper end of the ou~er leg 19 so as to provide a slidable but supportive bearing engagement with the respective i.nner leg 37.
The lower end of each inner leg 37 i5 also provided with an annular ~ushing or bearing 41 mounted adjacent the lower free end thereof for supportive but slidable engagement within the interior of the re~pec~ive outer 3eg 19. This bearing 41 is pre~erably constructed from separate ~ and generally opposed bearing halves 42 (Figures 4 : 20 and 5) which are of arcuate configuration and ~xtend through approximate~y 180-, with the halves being designed to surroundingly enclose the inner leg 37 ~ adjacent the lower ~ree end thereof. Each o~ the ; bearing halves 42 has a blocklike projection 43 which extends radially inwardly hereof so as to project : through a respective one o~ a pair of diametricallv opposed op~nings 44 formed through the sidewall of tne 1 g 37 s~ as to provide a securement of the bearing halves to the inner leg 37 when the latter is slidably~confined within the outer leg 19.
The vertical elescoping of each inner leg 37 into a respec~ive outer leg 19 defines a vertically-extendible telescopic leg assembly ~5, wi$h two such lèg asse~blies being associated with the fron~ top 27, namely one adjacent the right rear corner thereof, and the other adjacent the left rear corner thereof. Two such te~escopic leg assemblies 45 are W092~18033 ~ 1 0~ 4 7 9 P ~/US9~9815 also associated with the rear tsp 46, one of which is located adjacent each of the left and right front corners there~. The re r top 46 is of generally similar construction to the front top in that it defines thereon a generally planar and horizontally enlarged upp~r surface 47 which extends respectively between substa~tially parallel front and rear edges 4~ and 49, which front edge 48 is normally spaced rearwardly a small distance from the rear edge 32 of the front top so as to prevent intererence between the two tops. ..
Each telescopic leg assembly 45 has its own powered driving axrangement 51 (Figures 3 and ~
associated thexewith which, as illustrated in Figure 4, includes a screw-nut drive unit 52 cooperating between Lhe t~lescopic leg~ l9 and 37 for converting rotary drive motion into linear output motion. This drive uni 52 includes a ~ertically elongate drive scr~w 53 which pro3ects vertically upwardly in canti-~ ~0 levered relationship along the interior o~ the lower ::~ leg l9 and terminates;in a free upper end 54 dispoi~ed adjacent the upper end of the leg l9, which free end is provlded with a stop;55 associa~ed therewith. The ~; upper free~ end~54~of screw;53 is free o~ support ~rom the surrounding legs 19: and 37. Thi drive screw 53, at its lower end, a~uts against a thrust bearing 56 : which ~in turn abuts~;against an upper surface o~ a sùpport pla~e~5,~ he~latter being fixedly secured to ~: thè lower leg l9~ as~ by a screw 5S. This support :~ 30 plate 57 bears against the upper surface of a : pedestal-like support~59 which is fixed to and projects upwardly~from the~central~housing 16 so as ,:~:: ~ . to effectively pilot into the lower end of the lower :1 , : leg l9. ~ :
l ~ ~ Support plate:S7 centrally mounts therein a i bushing 61 through which projects th~ lower reduced-dia~eter drlve hub 62 of ~he s_re~ 5~. Ihis drive i:

:~ , 2108~73 W~92/18033 PCT/US91/09815--hub 62 has a drive pin 63 mounted diametrically thereacross so as to project radially outwardly in opposite directions.
The ~rive unit 52~aIso includes a nut asse~bly 64, such as a conventional recirculating ball nut, disposed ~or engag2ment with the rotatable screw 53.
The nut assembly 64 is nonrotatably confined between the diametrically opposed projections 43 defined on the bushing halves 42. Nut assembly 64 al50 has a threaded hub 65 which i5 nonrotatably secured to a surrounding end plate 66, the latter being directly engaged against the lower end of the upper leg 37.
This end plate 66 has the ou~er periphery thereof confin~d wi~hin an undercut groove 67 defined within the bearing 4l.
To effect rotational driving of the screw 53, the drive arrangement 5~ includes a reversible drive motor 68/ preferably a small low-voltage (i.e., 36 volt) direct-curre~ motor. This driYe motor 68 is mounted directly on the center housing 16 so as to be : dispos~d within the pedestal compartment ~3 substan~
tially adjacent~the respective lower~leg l9. The output Qf motor 62 is interconnected to the~screw shaft 53 throu~h a~speed-reducing gear train 60 which is dispQsed wikhïn~a compartment 71 as defi~ed within the~ cen~ral housing 16. This gear:train includes a :driving pinion 72 secured to the motor~shaft and ~:~ main~ained in direct:~driving engagem~nt;with an intermediate gear 73 mounted:on an intermediate idler ; 30 shaft 74. Gear 73 has coaxially fixed thereto a small-diameter driving gear 75 which directly meshes with:an output gear~76 which is no~ro~atably mounted : on a dri~ing sha~t 77. The shaft 77 is rotatably : : supported on the central housing in ~ertical coaxial ~: alignment with the screw 53. Driving sha~t 77 : : "
~: projects coaxially:upwardly into the interior of the support ~9 and has a yokelike axive coupling mem~e-:~

210~79 WO92/18033 PCT/US91/~9815 ;

7~ secured thereto, the latter having a diametral slot opening axially upwardly thereof so as to enable the drive end 62, 63 of the screw to be axially and nonrotatably engaged th~rewith. This creates a driving connection which can be readily axially separated i~ necessary.
The drive arrangement 51 also has a brake mechanism 81 ~ssociatPd therewith to prevent backward driving of the motor and hen~e lowertng of the table, such as c~used by loading of the table when the motor is stopped. This brake mechanism includes a brake wheel 82 preferably secured directly to the motor shaft ~3, which securement is to the upper end of the motor shaft in the illustrated embodiment. This brake wheel preferably includes several radially outwardly projecting brake lugs 84 associated there-with in circumferentially spaced relationship there-around, the number of such lugs preferably being at least three, and mors preferably at least five ~paced substantially uniformly around the periphery of the :~ ~ brake:wheel. These lugs are adapted to cooperate with a brake member 85 which is line~rly reciprocally movable g~nerally~radially of the brake wheel. This : ~rake member 85 is:secu~ed to the outer end of a plunger 86 a~sociated:with a conventional electrically ac~uated solenoid 87. The plunger 86 is .
normally retra~ted~into a released~dotted-line position~when the~soienoid is enexgized,~with tk.e plunger 86 and brake~member 85 being moved radially into a braking o~ e~gaged position by the action of springs (not shown~ when the solenoid is ~ de-energized. ~ -i~ : The brake member 85 has a lug-rece:iving slot or ,:
,~ groove 88 therein and configured so as to receive one of:the lugs 84 to restrain rotation of the brake ~:~ wheel and of the motor shaft secured thereto. The brake lugs 84 and tne brake slot 88 are both provide~

'I ~
~:

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W092/18033 PCT/US91/~9815 `~

with sloped camlike profiles on opposite sides thereof so as to ~ffect automat~.c cammed e~try of the lug 84 into the 510t 88 ~ven though ~hey may not be properly aligned as ~he braXe member moves radially inwardly to its engaged position. The sides and .
configuration of the 510t 88, particularly the enlarged mouth of the slot and the cam profiles formed on both sides thereof, coupled with the configuration and angular spacing between the lugs 8~, is such as to ensure that, irrespective of the stopping position o~ the brake wheel ~2, at least one ..
of the cam lugs 84 will always be dispos~d for engagement with the wide camlike mouth of the slot 88 so as to effect angular camming of the brake wheel into a position of full engagement with the slot 88 Further, the solenoid 87 is de-energized so as to permit brake engagement at a time when the brake wheel 82 has su~iciently slowed down, but not yat fully stopped, as to ensure that one of the lugs 84 : 20 will properly register with the slot 88 to permit full ~ngage=ent~of: the brake.
~ To:provide for~synchranized control o~ the pair : of motors 6~8 which~ar~:~associate~ with the right-and left telescopic leg ass~mblies of each tablè when ~: raising or lowering~the respective table9:there is provided:~;a~controller~91 whlch is preferahly mounted~
within one of the~pedestal compartme~ts 23 ~or controlling energlzation of ~he motor pa~r associated -~ with the table:being raised or lowered. This controller 91 in turn is prèferably activated, from a pendant-type keypad control 92 which can ~e posi-~: tioned for convenient access by an operator such as : on ~he front top 27, with the control 92, being ::~ joined to-the controller through a suitable~flexible low-~oltage cable 93. The pendant controller 92 is : of a multiple-key construction for actuation by an ~ operaLor so as to prcvide control over ~e selection ; WO g2/l8033 2 1 0 ~ ~ 7 9 PCT/US9l/Og8l5 and movement of the individual table tops. The elec-t:rical energy, preferably low-voltage direct-current energy, is supplied to the controller 91 and control 92 from a transformer which is preferably mounted in the interior compartment o~ the other pedestal, w~ich transformer in turn has an e~teriorly extending supply cord (not shown) adapted ~or plug-type connec-tion to a con~entiona~ electrical receptacle.
To enable the controller 91 to control and 10 synchronize the rota1:ion o~ the energizea motors 68 to maintain the table top in a ~ubstantially level condition and at the same-time permit movement of the table top to ~rarious predetermined heights, as explained in detail hereinafter, each drive arrange-~ent 51 has a rotatian sensi~g and signal ~enerating assembly 94 (Figures 4-6) associated therewith. This asse~bly 94 includes a counting wheel or disc 95 which is fixed to and rotates ~with the brake wheel 82~ Counting wheel 95 ha a slot 96 extending axially therethrough~over a pradetermined radial extent of ~he:wheel periphery. A photocell-type sensor 97 is stationarily m~unted adjacent the counting wheel 95~:and~includes ~n emitter portion 98 disposed adjacen~:one axial side:of the: counting wheel and:a receiver portion 99 disposed adjacent the ~ other a~ial side,~:whereby the sensor 97 transmit one : signal per motor revo1ution each time the slot 96 passes between the emitter and receiver portions.
Relerencing now Figure. 7, there is diagram-matically illustrated electrical circuitry associated with the controller 91 for controlling energization of~the motors 68 and the associated brake solenoids 87.: As illustrated by Figure 7, the table possesses four separate motors 68, namely the right and left motors (M~" Mfl) associated with the front ~ble, and the righ~ and left motors (M~r ~ Mb~ ) associated with ~:~ the rear ta~le. Each of these motors has a ~rake 3~7~
WO 92/1B033 ; . - P~/VS91/~815. '~

solenoid 87 and a photosensor 97 associated there-with, all being diagrammatically depicted in Figure 7.
Conventional alternating current electrical en~rgy is supplied to a transPormer 111 located i~
one of the pedestal compartments. The tran~fo~mer 111, in the illustrated embodiment, has a sp~it secondary so as to provide a first higher-voltage direct current driving circuit 112, such as a 36 volt DC circuit. The transformer also provides a second lower-voltage DC circuit 113 which is supplied to a suitable voltag regulator circuit 114 from which multiple DC voltage taps of di~ferent voltage can be provided. The output fro~ the regulator circuit is also supplied to a microprocessor 115.
The voltage rom the driver circuit 112 is : suppli~d through a first branch circuit to the brake sole~oids 87 a~d, ~or this purpose, the driv~r circuit includ~s therein a main solenoid on-off relay switch 116 whi h:, when in the normally open position, prevents energization of any of the solenoids 87.
: With this switch~116 ln a closed position, however, then the dxiver voltage is supplied ts a further series-co~nected:double-pol~ relay switch 117 which controls sel~ction.of the front and back ~ole~oids.
:~ That is;~the switch~117 in one position permi~s : solely the two solenoids 87 associated with the front kable to be energized, whereas this switch 1~7 in the other posi'ion enables solely the two solenoids 8 associa~ed with the back table to be energiz~d.
The~driver circuit 112 also connects to a second branch circuit for~supplying driving vol~age to the ~: motors 6~o This branch of the driver circuit 11 connects to a supervisory circuit 118 which is ' capable of switching a DC voltage output to supply power to the motors if the microprocessor is ; ~ operating in a normal mode. The outpu~ from this .

W~92~18033 21 Q ~ ~ 7 9 PCT/USg1/09B15 - ~5 -supervisory circuit 118 is connected to a main motor on-off relay switch 119 which, in the normally open position, prevents flow of DC voltage to any of the motors 68. The output side of this main on-off switch 119 in turn is connècted to a pulse modulator switching circuit 121 which includes parallel branches and receives appropriate input si~nals from a pulse width controller 127 associated wlth the microprocessor 115 for varying the motor supply voltage. More specifically, this switching circuit 121 ~urns on and off as a function of th~ signals received from pulse width generator 127 so as to create a wave form or pulsed DC voltage outpùt in each branch circuit which is connected respectively to one of a further pair of parallel-arranged polarity switches 122 and 1~3~ The polarity switch : 122 controls solely the pair of motors associated with the front top, whexeas the polarity ~witch 123 : controls 501ely the pair of the motors ~ssociated : 20 with the ~ack table top. Each o~ the~e switches 122, : 123 is of a double-pole relay construction so that it causes the associated~pair of motors to rotate in a ~: first;direction when in one posi~ion to cause upward table top movement, whereas the motors are caused to ~: `rot~te in the other:direction when~the switch is in ~ thé ~sécond position so as~to;eff~ct lowering of the : ~ r~spective table top. The outputs from switches 122 : : an~:~I23 are then fed a front/back relay ~otox switch:124 which is a:lss a two-position or dauble-~pole switch, one.position ~eing coupled to solely the : pair of motors associated with the front table top, the other position being coupled solely to the pair : of:motors associated:with the back tàble top.
The micropro~-essor 115 includes therein a counting/detecting/comparing means 126 which receivec input signals from the four photosensors 97, which sen ors individually eri' a sisn~l pe~ ro!atior o~

2108~79 W~92/18033 PCT/US91/~81 the respective motor 68. The signals inputted into th~ counter 12Ç are counted for each motor so as to define the position or height of the up~er table leg associated with the respective motor~ In this regard, the counter has a "zero'l electronic count position which substantially corresponds to the lowest table height position (for example 26 inches), and the counter has an internally defined record which relates the number of counts to prede~ined table height positions. The counter continuously adds to or subtracts from the count for each motor as the associated upper leg is raised or lowered by the respective motor so as to determine the table height.
The signal input rate received from the pair of photosensors 97 associ2ted with the pair of energized motors are also compared in t.he counter/comparator 126. If the ~ignal rates are different duP to one motor running faster than the other motor (such as due to the other~motor being under a h avier load), then ~he counter/co~parator 126 transmits an adjust ing signal to the pulse width controller 127, which in turn adjusts the branch of the swit hing circuit , 121 associated wi~h the faster motor so as to adjust or modulate the ~idth~of the voltage pulse to reduce the~average voltage of the output wave form suppli~d to the fast~r motor~This thus slows down the fa ter ~ :, motor to a speed substantially equa~ to that of the ~slo~er motor. ~ ~
~: The counter/rate detec~or/comparator circuit : 30 126, as~associated with the microprocessor, : continuously monitors the pulses or signals xe eived ; from the photosensors 97 so as to count the number of : rotations received from each photosensor, and also -monitors the signal~rate received from each photo-sensor and compares both the total counts and the si~nal rates of ~he two photocells associated with the pair of energized motors so as to control both WO92/1~033 21 Q 8 ~ 7 9 i p ~/US91/Og815 the speed and position of motor shaft rotation associated with the energized motors, so that the table top is maintained in a horizontal and level condition. For example, when the top is being moved ~for example raised) from a ~irst height to a second height, both the right and le~t motors are energized but may rotate at slightly different speeds such as due to an unbalanced load being positioned on the table more directly o~er one of the motors. Hence, to mo~e from the first height to the sacond height requires a substantially ~ual number of predeter-mined counts ti.e.t motor revolutions) for each motor, and this counting information is moni~ored b~
the circuit 126. If one motor is rotating fast r, which is indicated by the monitoring and comparing of the count rates by the circuit 126, then the circuit 1~6 will detect this differe~ce and emit a correcting signal to the controller 127 which in turn controls the switching circuit 121 to slow down the faster motor. Howe.ver, since the total revolutions and hence:total co~nts associa~ed with the faster motor will still be greater than that of the slower motor, even after the faster motor is slowed down to a speed : substantially equal to that of the slower mntor, the zireui~ 1~6 also monitors the total counts associated with: ~he two motors and makes an adjustment tv still further slow down:~he motor having th2 higher count ~:~ (ori~inally the faster motor~ until the motor having the smaller count catches ~p, whereupon circuit 126 ~gain restores speed equality ~o the two motors so as to mai~tain the table top in a horizo~tal level condition. While th oretically the circuit is : designed to maintain su~h equality particularly with respec' to the counts associated wi~h the pair of energized motors, nevertheless in practicality the circuit 126 will provide a small tolerance (which wili b~ only a small number of counts) necessary in W092J~ 8 ~ 7 9 PCr/US91/~g$15 -order to permit prartical operation of this system wi~hout ha~ing any signi~ic~nt effect on the desired horizontal lev~l cond~:tion of the table top.
The controller 91 is provided with a pendant connector 129 which couples to the microprocessor 115 ~or supplying numerous signals thereto as inputted by the operator depressing the keys of the pendant control ~2, The microprocessor 115 also includes a timing and controller circuit 128 for tran~mitking control signals to shifting solenoids a~sociated with the switches 116, 117, 119, 122, 123 and 124. These control signals from ~he microprocessor control the timing and shifting of the respective switches. For example, these signals control and coordinate the energization and de-energization of the solenoids 87 with respect to the corr~sponding motors 68.
The pendant control 92, a preferred embodiment of which is illustrated by Fi~ure 8, is constructed as a small portable unit r~sembling a thin boxlike - 20 housing having a display screen 132 on ~he upper surface theraof. The pendant control 92 also prefer-ably has a visual indi~ator 135, such as an LED. The upper surface~of the pendant 92 is also pro~ided with a plurality o~ keys for inputting info~mation or co~mands, including a~plurality of numeric function -: keys 133 and ~ plurallty:of operations keys 134, ~: which keys hav~: their functions de~ined thareon as- --shown in Figure 8,: and as explained hereinafter.
As to the visual display means 132 (Figure g), it includes a firgt~display 136 entitled SEQU~NCE, a ! ' second displ y 137 en~itled EVENT, and a third ~; ~ display entitled~POSITION. These displays are positioned in sidewardly adjacent relationship, and ~ ~ each has an icon associated therewith at the: position : ~ indicated by dotted lines 139 in Figure 9, which icon . when energized~states STORED.

~ :, WO92/18033 210 8 4 7 9 P ~/U~91/09815 The ~isual displays means 132 also includes a fourth enlarged display 141 located substantially in the middle of the overall display area. This display 141 i~cludes upper and lower display regions in which the words REAR and FRONT permanently appear. Numeric height displays are positioned to ~ppear in the upper and lower regions so as to indicate the heights (in inches or centimeters) of the respective rear and front table tops~
Lastly, the visual display means 132 includes a fifth disp~ay 142 adjac~nt the rightward side thereof, which display 142 indicates the function of a timer and can display hours and mi~utes. Four separate and independently energizable icons are disposed directly below the display 142, which icons are in the positions indicated by dotted line at 143, : 144, 145 and~l46. Th~ icon 143 when en~rgized states PRESS STORE, icon l44 when energized indicates PRESS
ENTER, icon 145:when energized states:TO CONTINUE, and icon l46~when energized states PRESS FVENT.
: ~ The functions~associated:with the keys of the pendant control 92 are associated with~and operate a program which is associated with the controller g~ so ~ as to:p~ovide for programmed:operation of~the table : ~ a~rangement~and~hence permlt fron~and rear ~ops to ;::: be:positione~ at;numerous~héight locations, which locations:ca~ be~stored in the:memo~y of the program, with the locations~ bein~reca:llable either indivi-: - :
dually or in a predetermin~d sequence, as explained below.
HoweYer, if:~programmed control of the table tops is~not~desired,:the~the table arrangement can be provided with a~modified pendant control 92' as illustrated by Figure 10, which pendant control 92' ` ~ pr~vides~a FRONT Xey ~53 for activating the motors associated with the front top, a RE~R key 154 for : activating the motors associated wiih the rear top, 2 ::
~: :

w~g~/lg~ 1 0 8 ~ 7 9 PCT/US91/~98l~
"

HIÇH SPEED key 155 for activating the motors at high speed, rather than the normal low speed acti~ation which would otherwise occur, an UP key 156 when raising o~ a selected top is desired, and a DOWN key lS7 ~or lowering the selected top. The switch 151 merely activates the control 92l, and i~dirator light 153 is energized when switch 151 is ON. With ~his pendant control 92', the operator manually ontrols all raising and Iowering functions of the table. The operator selects which table is to be moved by depressing either the FRONT key 153 or the ~EAR key 154. Therea~ter, assuming high speed is desir~d, the operator then depresses the HIGH SPEED key 155. The operator then manually depresses UP key 156 or DOWN
~ey 157 and maintains the selected key depressed until the selected top is respectively raised or lowered to the desired position.
The operation of the table arrangement 10, particular~y wh n using the pendant controller 925 of Figure 10, will b~ briefly described to ensur~ a thorough u~der~tanding thereof.
When a computer is supported on the table arrangement 10, the keyboard will normally be posi-tioned on the front top 27, and the CRT or scr~en will normally be:positioned o~ ~h~ r~ar ~op 46. When a change in the elevation~of one or both tops is desire~, the operator depresses the ON key 151 to : activate the control 92'. The operator then : depresses the selec~ed table button, such as the REAR
~ 30 key 154 which will result in activation of tbe ::: front/~ack solenoid switch 117 and front/back motor .
: switch 124. The operator will the~ normally depress the~HIGH SPEED key 155 to cause high speed motor ~ operation, if such is deslred. The opera~or will :~- thereafter depress either ~he UP key 156 or the DOWN
157 depending on the desired direction of table move-ment. This hence controls the switches 116, 11~, 122 .

- W~92/18033 ~ 1 0 8 ~ 7 9 PCT/USg1/09$15 and 123 so as to permit energiæation of the brake sslenoids 87 associated with the top table motors to release the brake members 85 ~rom the brake wheels 82, and energization o~ only the pair of motors associated with the selected rear top table so as.to cause the selected upward or downward movement of the table top.
During energization of the motors, the motors drivingly act through the gear train 69 and the di~engageable coupling 63, 78 to effect rotation of the upwardly-ca~tilevered drive screw 53. This screw 53 cooperates with the nut 64, which is constrained from rotating, whereby the nut 64 is linearly displaced either upwardly ~r downwardly depending upon the direction of rotation, there~y causing a corresponding ~erti al telescopic displacement of the inner leg 37 within the outer leg 19. During the slidable vertical displacement of the inner leg 37, the lower bearing 41 maintains a slidable engagement with the inner wall of the out~r leg 19, and at the same time the top bearing 39 maintains a slidable engagement with~the outer wall of the inn~r leg 37.
During ro~ation of the pair of drive motors 68, the photocell 97 asociated with each rotating motor trans~its~a signal~for each motor revolution to~the counter/comparator:126 which:counts and compares the : : rate of signals from the two photocells associated with th pair of~energized motors. II the~motor rotational rates are different, such as due to one side of the table being more heavily lo~ded than the other so as to cause slow down of one of ~he motors, then the counterJcomparator 126 transmits a correc-~: tive signal to the pulse width controller 127 so as t~ adjust the switching ~ircuit 121 to modulate or adjust the wave form~and hence adjust the average ~ vo~ltage which is supplied to the higher speed motor, : ~ thereby reducing tne speed o~ ~he highe~ speed motor .

21 08~73 ;; - 22 -so as to equalïze right-to-left table elevations and the rates of chanye thereof, so that the two telescopic legs associated with the moving top (such as the rear top) are simultaneously and synchronously extended or contracted. In addition, the counter.
electronically counts the number o~ signals receiv~d during the rotational cycle of each of the activated motors and, upon receiving a stoppage or "off 1l signal, automatically causes continued operation of lO one motor for a short additional time period i~
n~cessary so as to cause both motors to preferably undergo an equal number of revolutions, thereby ensuring that the table top r~mains horizontal. The rotation of both motors continues long as the operator maintains the selected key 156 or 157 depressed, with rel~ase of the key terminating motor operation. Termination o* motor operation de-energizes, after a predete~mined time delay, the respective solen~ids and permits the brake members 85 20 ~o re-engage the respective brake whee1s 82.
T~e operation of the table arrangement to provide for programmed control over table h~ights, particularly when using the pendant control 92 of ~: Figures 8 and 9, wiIl now be described, particularly with r~ference to Figures ~l(A) and ll(B) which 3 diagrammatically illustrate programming and operating the table.
The front and rear tops 27, 46 of ~he ~able are ~: movable individually and independently through a 30 significant vertical extent; typically from a lower-: most position which is about 26 inches above the ~: floor ~urface, to an uppermost position which is i' : about 42 inches above the floor. In addition, with :1 .
. : the table tops in their lowermost positions, the : microprocessor 115 defines an el~ctronic "zero~t coun~
~i ~ position, whereupon there is defined in the micro-processor a "position table" whereby each height o-i::

... . . .. , .. . ~ .. . .. .

. WO92/18033 210 8 ~ 7 9 PCTJUS91/0~815 each top, in predetermined height increments which are preferably about l/2 inch increments, is defined according to a predetermined number of counts, which ccunts corresponds to a predetermined number of motor revolutions.
Referencing now the programming of the table arrangement l0 as illustrated by the step chaxt of Figure ll(A), the operator first detPrmine~ whether there is a desire to program one or more predeter-mi~ed height positions or }ocations, as indicated atstep l~l~ Since such is normally desired, the operator then goes to step ~62 so as to permit creation of a desir~d table height position H. To create a predetermined table height position, the operator initially moves the rear top 47 to the desired height position by depressing the RE~R key, : then thereafter normally depressing the HI~H SPEED
key, and then depressing and maintai~ing dPpressed the UP or DOWN key until the rear top reac~es the desir~d height. During movement o~ the xear top, the instantaneous top height will appear in th~ upper : portion:of the~display l41, and ~he operator ~ill main~ain the UP or DOWN key depressed until reaching the de ired heigh t which will be displayed at 141.
The operator wiil then;acti~ate the FRONT button, followed~by act~ivation~o~ the HIGH SPEED ksy, ollowed by activation and continued depression of the UP or DOWN key to cause ~ertical displacement of the ~ront top. :As~the front top is displ~ced, he height thereof will be instan~an~ously displayed in ! ' the lower portion:of the display 141, and the : operator will ~ontinue movement until the top reaches . the desired height, and the display 14l will indicate the new height. ~At that time the operator~will then depress the POSITION key and assign a unique label to this position~by depressing one of the numeric-keys ~ 133, such as by labellng t~is position "l". The :~

WO92/18033 PCT/US,91/V9815 operatc,r then depresses the STORE, key so as to store the predetermined table height H, which predetermined height represents two ~eight values, one for each of the front and rear tops. If the operator does not depress the STORE key within a predetermined number of seconds following entry of the position label, then the icon 139 will flash the prompt "press store"
so as to guide the operator as to the required next step. If STOR~, is not depressed within a predeter-mined time period, then the visual display will go static. .
After the operator has press~d STORE so as to ~omplete step 163, the operator then determines whether crea~ion and storage of additional height positions is desired, as indicated at step 164.
Since normally several height positions are desired, the operator will then return and go through the same sequence as indicated at steps 162 and 163 until the desired numker of different predet~rmined height 20 p~sitions have been defin~d and stored, each bein,g stored und ~r a different or uniqu~ label (i.e., a different numeric identificatiQn for the height position).
If nothing fuxther is required other than storage of se~eral predetermined height positions, then the operator can resume normal use and operation o~ the ~able, inc1uding manually controlled raising l~ a~d lowering of ~he~front and rear tables as desired.
I Alternatively, the oper.tor can recall any predeter-30 mined and stored height posltion by operation in the manner outli~ed in Figure ll(B), explained belswO
'~ In addition, and again referring to Figure ! ll~A), the operatvr can also program a sequence of ta~le events, whereby each event repr~sents a predetermined table height (two height valu~s, one 1 for each~of the front and rear tops~ in combination 3 with a determined time interval during which the tops ;~

'`' WOg2/18033 ~1 Q 8 ~ 7 9 PCT/USg1/~815 - ~5 -are maintained at the predetermined height. A
plurality of such eve~ts can be de~ined and then programmed into a desired seguence so as to ensure that the front and rear tops will be positioned and moved so as to provide for greater flexibility and yet still provide control over operator movements and positions.
To create a sequence of table events, the operator depresses the SEQ~ENCE key and then defines a unique identifying label L for the sequence as indicated at step 166, which label L will be a numeric label ef~ected by depressing one of the numeric Xeys 133, such as by labeling the sequence ~ . This then causes the "event" function of the microprocessor to be automatically activated and in fact the EV~NT di play 137 is initially assigned the identification 5'l'l to designate the first event. The POSITION function is then also automatically activa~ed by th2 microprocessor and, as indicated at step 168, the operator~the~ selects one o~ the previou~ly-stor~d h i~ht position Hn by inputting (by depressing the~selected numeric key 133) the numeri~
label or identi~ication for the s~lected height position, which label appears in display 139. The ., .
heights corxespo~ding to the label also appear in ~ display l~ If this is not the ri~ht position, the ::~ operator can, in a timed sequence, scroll through the s~red height positions by inputting different po5i-tion numbers through activation of the numeric keys 133. When the operator locates the,desired height : positi~n by inspection of the visual display 141, the ~perator waits the predetermined time whereupon the micro~rocessor llS:automatically activates the timer func~ion and, as indicated at step 169, the operator : keys in, by sequential depression of the mlmexic keys 133, the desired time interval for maintaining the : ~able tops a~ the selected height Hnl which time will 21 ~ ~79 WO92/1~033 . PCT~U~91/~g%lS -

- 2~ - .
visually appear in display 142. This selected time, in combination with the selected p~edete~mined height pasition, define a single table.event.
If the operator wishes to define additional eve~ts in the seguence (step~172), then the operator depresses the E~ENT key so as to store in the micro-processor the previously defined event or, if the operator takes no action for a predetermined short time interval, then the icons 145-146 both flash 10 stating "to continue press event". If the operator again takes no action within a predetermined time interval, icons 145-14~ are de-energized and icon 144 is energized to flash "press store". If the operator still takes no action withi~ a predetermined time, then the display returns to its original static condition.
After the operator presses the EVENT key so as to store the previously defined event function, then the icon 139 is energized so that STORED momentarily appears is display areas 137 and 138~ Then the microprocessor automatically presents the next event : number (such as '~2"~, in the display 137, and then : thereafter automatically activate-~ the "position function". The operator then re~eats steps 168 through 171 by depress~ing one of the numeric keys 133 to input a differe~t height label H~1~corresponding to another predetermined stored height position tthe height:values o~ whirh then appear on the display 141~, and then inputs a des~ired t~me interval for use with this height position.
If no more events are desired in the:sequence, the ~perator then depresses the STORE key (step 173) : which stores all of the infonmation which defines each event and also stores the entire sequencP of events for later recall. The icon 13g associated with each of displavs 136-13B is then energized for a short period of time to indicate "stored". The

3 21 0 ~ ~ 7 9 PCT/US91/09815 - 27 ~
overall display 132 then returns to a static mode and the heights displayed in area 14l correspond to the actual heights of the table tops.
I~ the operator desires to define a further sequence as indicated at step 174, then the opera~or again repeats ~teps 166-173, with the primary differ-ent being that the operator will define the ~exk sequen~e by means of a unique label Sl as indicated at step 166, such as by identifying it as sequence "2".
On the other hand, if no more sequences are.
desired, then the programming function is ended, and the operator can resu~e operation of the table in the desired manner.
Referring now to Figure ll(B), the activation of the table utilizing programmed height positions, either individual positions o~ sequenc~d table events, will now be explained.
If the operator determines that utili2ation of a stored ~equQnce is not desired~as indicated at step 175, then as indicated~ at step 176 the operator selects a desired stored height position Hn by depressing the RECAL~ key folIowed by~depression of the PUSITION key. The operator then selects the desired:stored position:by d pressing the appropria~e nume~:ic key 133,~whereupon the pvsition nu~ber will appear in:~he:display 138, at which time the stored height~values corresponding to this position will also appear in~display 14}. I~ this is not the right position, the operator can, in a timed sequence, .:: 30 ~scroll through the~stored height positions by input~ing different position numbe~s through activa-tion of the numer~ic keys 133. When the operator , :
: lo~ates the desired height position by inspection of he visual display l41,~ ~hen the table is activated :
: : ~ at s~ep 177 bv depression of the ENTER key. This caus s the display~14l to return to the actual table height values, following which a visual andJor :

w~ g2/280~3 8 ~ 7 3 PCT/US91/~9815 ~

audible alarm (step 178) is emitted so as to alert the operator as to impending table movement. This includes activation of an audible alarm located in the pendant c~ntrol 94, and flashing~'of the LED 132 on the pendant. Thereafter the brakes associated with the rear table motors are released and the rear motors are automatically energized (step 179) in the correct direction so as to e~fect raising or lowering of the rear top to the predetermined height. Upon reaching this position, the rPar motors are automatically stopped and braked, whereupon a further visual and audible alarm (step 181) is automatically sounded, and therea~ter the front top automatically moves (step 182~ to the new pr~determined height in the same ma~ner as the rear top. Upon reaching this height, then the new hei~hts for both tops are displayed at ~rea 141, and the table tops then remain in this new height posi~ion until the operator ~lects to move them. Hence, after selecting ~he predetermined height position a~d activating the system, ~he actual movement of the table tops occurs au~omatiGally and requires no further input or control by the apera~tor, and at the same time the ~: display 141 automatically tracks and displays the heights of the tops:as they are moved.
: : On the ot~er hand, if the operator desires at , . ~
step 175 to ac~uate~a sequence of table events, then the operator~first~depresses the REC~L~ key followed :~ by depressi~n~of:the SEQUENCE key, and th~n depresses one of the numeric keys 133 corresponding to the selected sequence, which sequence number will appear in the~display 136.~ Thereafter the ~irst eYent will automati~ally be displayed ~step 185) at the display 137, and the position identifying location, the position heights, and the time interval, all corresponding to the selected event, will be displayed in the remaining displays 13/, 141 and 142 .. ... . . .. ... . . ... . . . .

-- WO92/18033 2 1 0 8 4 7 9 PCT/USgl/~815 Zg If the operator wishes to start with some other event or merely review the data associated with the sequenced events, then the operator can press the EVENT key whereby the program wîll slowly scroll through the se~uenced events and display the pertinent data (i.e., table heights and time) for each event.
When the operator has determined which event is to bP initiated first, as indicated by the display lQ 137, then the operator depresses the ENTER key (step 186) to activate the ~equence, which activation will occur with the event di~played on the scraen 132. At that time the existi~g table height position will reappear on the screen 132, the visual and audible alarms are then activated (step 187), and thereafter the xear top is automatically mo~ed to the destina-tion height (step 188);, ~ollowed automatically by ~urther activation of t~e audible and visual alarms (step 189), and then followed automatically by move ment of the front :~op to the predefined destination height (step 191).~ With both tops position~d at the des~ination heights, whi~h will be visually indicated at the display 141, the timer is then acti~ated for : maintaining the tops at these h~ights until the timer times out, which~: timing out function will ~e readily visible by inspection of:the display~42. Whén the timer times out~ then an audible/visual ala~m is activated and the~microprocessor auto~atically ~: displays the next sequenced event (including the ta~le heights and~timej on the screen at areas 137, .
138, 141 and I42 (st:ep 195) and also flashes the LED
135, so as ~o indicate~to the operator that the prior :~:: event has terminated,~and to also provide the ~:; : operator with visual identification a5 to the nex~ : event (both height~position and ~ime). At this timP, the icons 143 and:145 are also energized and flash "press enter to continue". However~ since the 2108~79 W~92/18033 PCT/U$91~0~815;-operator may be unable to immediately initiate the next table event, the table tops will remain at the prior event heights and the next eve~nt along with the prompts will continue to be displayed for a predeter-mined time, such as about five minutes. At that .
point in time, ~urther prompts (step 196) are given to the operator, particularly in the form of an audible alarm. If after a predetermined time period the operator does not response, then the screen 132 goes static and displays the current table positions.
However, if the operator does respond by pressing the .
ENTER key within the allowed time interval, then the next event is automatically actuated and hence the operations starting at step ~87 again automatically repeat.
The table arrangement lO can thus be programmed to pro~ide a plurality of predetermined h~ight ~osi~
tions, with the various predetermined height posi-tions being coordInated with time intervals to define a plurality of table events which can~be sequenced to permit positioning of the table top~ se~uentially in a plurality of desired positions so as to optimize opera~or comfort a~nd health, with the table tops being automaticall~ moved from position to p~osition :: as éach evenk of the sequence times ou~ merely by r~uiring an input signal from the operator to permit nitiation of the~:next event.
~ :While the in~ention as described above :~ illustrates use of~a pendant keypad control 92 as a preferred e~bodiment ~or controlling the progra~med opera~ion of the ta~le arrangement, it will be appre-ciated that other arrangements can also be provided ~or this purpose. For example, the~co~trol 92 could additionally be provided with a card reading slot and ~: associated internal card reading capability so ~hat a desired table mo~ement seguence could be magne~ically : preprogrammed on a card (similar to a credit cardJ

WO92/1~033 21 ~ ~ 4 7 9 PCT/US91/0981 which could then be read into the control g2 so as to permit storaye of the desired table arrang~ment sequence therein. With such a arrangement some of the programming keys on the control 92 could be eliminated if preprogamming solely by means of a.
magnetic card was desired.
As a still further al-terna~ive for both programming and controlling the table operation, the pendant control could be replaced by a central computer which would be connected to one or se~eral such table arranyements 50 as to not only control but .
also monitor the positional arrangements thereof. In place of a central ~omputer, it will be appreciated that the programming and controlling of the table arrangement could also be accomplished by utilizing t~e computer which is supportad on the table whereby the computer operator could use his/her own keyboard ~or activating and progra~mi~g the table arrangement.
Although a particular preferred embodiment of the invention has been:disclosed in detail for illustrative purposesr it will be:recognized that :~ variations or modi~ications~of ~he disclosed : ~ apparatus, including the rearxa~lgement of parts, lie within the scope of the present inven~ion.
~ , :
:
~::

,

Claims (23)

What is claimed is:

1. A method of defining and automatically controlling the operation of an adjustable work station having separably movable front and rear height-adjustable support surfaces (27,46) which are respectively adapted to support thereon the keyboard and an associated information display screen, said method comprising the steps of:
adjusting the respective heights of said front and rear support surfaces (27,46) to a desired relative height position wherein said front support surface (27) is disposed at a first height and said rear support surface (46) is disposed at a second height, determining first and second height values which represent said first and second heights, recording said first and second height values, and repeating said steps of adjusting, determining and recording in order to define a plurality of desired relative height positions and produce a corresponding record of said relative height positions in the form of a plurality of relative height position entries which are each defined by a pair of said first and second height values;
selecting one of said pairs of first and second height values to which it is desired to move the support surfaces (27,46) from their current relative height position;
initiating automatic control of the adjustable work station in response to a user input so as to effect movement of the support surfaces (27,46) to the first and second heights corresponding to the selected pair of height values, including the sequential steps of emitting a warning indication of impending height adjustment, then moving said rear support surface (46) to the predetermined height corresponding to the predetermined pair of height values, thereafter emitting a second warning of further impending height adjustment, and then moving said front support surface (27) to the height corresponding to the predetermined pair of height values.

2. A method of defining a control sequence for use in controlling the operation of an adjustable work station having separately movable front and rear height-adjustable support surfaces (27,46) which are respectively adapted to support thereon a keyboard and an associated information display screen, said method comprising the steps of:
adjusting the respective heights of said front and rear support surfaces (27,46) to a desired relative height arrangement wherein said front support surface (27) is disposed at a first height and said rear support surface (46) is disposed at a second height, determining first and second height value which represent said first and second heights, recording said first and second height values, and repeating said steps of adjusting, determining, and recording in order to define a plurality of desired relative height arrangements and produce a corresponding record of said relative height arrange-ments in the form of a plurality of relative height arrangement entries which are each defined by a pair of said first and second height values;
selecting one of said pairs of first and second height values and assigning a time period thereto, selecting another of said pairs of first and second height values and assigning a time period thereto, and deciding that said support surfaces will first move from their current relative height arrangement to the relative height arrangement associated with said one pair of height values and will thereafter move to the relative height arrangement associated with said another pair of height values.

3. A method according to Claim 2, including the steps of:
providing an automatic height adjustment control means (91) for automatically adjusting the height of said front and rear support surfaces, including a timer means (128) for measuring elapsed time and indicating that a predetermined amount of time has elapsed; and actuating said automatic height adjustment control means to effect automatic and sequential execution of the following steps in the following order:
adjusting said rear support surface (46) to the second height associated with said one pair of first and second height values, thereafter adjusting said front support surface (27) to the first height associated with said one pair of first and second height values, thereafter main-taining said front and rear support surfaces (27,46) at said last-mentioned heights for the time period associated with said one pair of first and second height values, and thereafter indicating that said last-mentioned time period has elapsed; and actuating said automatic height adjustment control means (91) to effect automatic and sequential execution of the following steps in the following order:
adjusting said rear support surface (46) to the second height associated with said another pair of first and second height values, thereafter adjusting said front support surface (27) to the first height associated with said another pair of first and second height values, and thereafter maintaining said front and rear support surfaces at said last-mentioned heights for the time period associated with said another pair of first and second height values.

4. A method according to Claim 3, including the steps of:
providing a predetermined user input to said control means in order to initiate the actuating step, thereafter providing a warning indication to inform the user of impending work station adjustment prior to adjusting the height of said rear support surface (46), and thereafter providing a further warning indication to inform the user of a further impending work station adjustment after said rear support surface (46) reaches the second height but prior to initiating adjusting movement of the front support surface (27).

5. A method according to Claim 4, including the step of:
maintaining said front and rear support surfaces (27,46) at the mentioned heights associated with the first-mentioned actuating step upon elapsed of the mentioned time period until receipt of a predeter-mined user input which permits initiation of the second actuating step.

6. A method for automatically controlling the operation of an adjustable work station having separately movable front and rear height-adjustable support surfaces (27,46) which are respectively adapted to support thereon a keyboard and an associated information display screen, said method comprising the steps of:
initiating automatic control of the adjustable work station in response to a user input;

thereafter providing a warning indication to inform the user of impending work station adjustment, thereafter adjusting said rear support surface (46) to a first predetermined height, thereafter adjusting said front support surface (27) to a second predetermined height, thereafter maintaining said front and rear support surfaces (27,46) at said predetermined heights for a predetermined time period, and thereafter indicating that said predetermined time period has elapsed;
thereafter monitoring user input activity and simultaneously maintaining said support surfaces (27,46) at said predetermined heights until a predetermined user input is detected, thereafter initiating further automatic work station control in response to said predetermined user input; and thereafter providing a warning indication to inform the user of impending work station adjustment, thereafter adjusting the height of at least one of said support surfaces (27,46), and thereafter maintaining said support surfaces at their current heights for a predetermined time period.

7. A table, particularly adapted for supporting a computer, comprising:
a base (11) adapted for deposition on a support surface such as a floor, said base having a pair of horizontally-spaced upright pedestals (18);
a front top assembly (12) including a horizontally enlarged worksurface-defining front top (27) having a pair of sidewardly spaced and generally parallel elongate legs (37) fixed to said top and projecting downwardly therefrom in cantilevered relationship, each of said legs being vertically slidably supported on a respective one of said pedestals (18);

a rear top assembly (13) including a horizontally enlarged worksurface-defining rear top (46) having a pair of sidewardly spaced and generally parallel elongate legs (37) fixed to said top and projecting downwardly therefrom in cantilevered relationship, each of said legs being vertically slidably supported on a respective one of said pedestals (18);
a powered drive arrangement (51) including front and rear lifting means (52) respectively coacting with said front and rear top assemblies for effecting vertical movement thereof to adjust the height of the respective front and rear tops;
controller means (91) for controlling activation of said front and rear lifting means including programming means (115) for permitting storage of predetermined height locations each representing front and rear height values corresponding to predetermined heights of the respective front and rear tops, and means (115) for automatically activating said front and rear lifting means to move said front and rear tops to heights defined by a preselected said height locations; and operator-activated control means (92) for permitting operator election of said preselected height location and initiation of said activating means:

8. A table according to Claim 7, wherein said controller means includes timing means (128) for defining a predetermined time interval corresponding to said preselected height location for maintaining said tops at said heights for said time interval.

9. A table according to Claim 7 or Claim 3, including sequencing means associated with said controller means (91) for defining a series of table events wherein each said table event defines a distinct stored predetermined height location and a distinct defined time interval, and said activating means causing automatic activation of said series of table events only upon receipt of a signal from said operator-activated control means (92) so as to permit activation of the next event.

10. A table according to Claim 7 or Claim 8, wherein said operator-activated control means (92) comprises a portable pendant-type assembly which is removably positionable on one of said tops and is disposed remotely from said controller means.

11. A table according to Claim 7 or Claim 8, wherein said activating means includes means for sequentially activating first said rear top and then said front top.

12. A table according to Claim 7, wherein the lifting means (52) as respectively associated with each said top assembly includes a pair of powered drive means (51) each associated with a respective one of the legs, each said drive mean including a low-voltage direst current electric motor (68) drivingly coupled to a rotary input of a rotary-to-linear motion converter means (52) having a linearly-movable output coupled to the respective leg for effecting vertical raising and lowering of the leg;
and said controller means (91) including means for simultaneously controlling the rotation of the motors (68) of said pair of drive means associated with one of said top assemblies for synchronizing the vertical raising and lowering of the pair of legs.

13. A table according to Claim 12, wherein said controller means includes means (126) for sensing when one said motor (68) of said pair of drive means is rotating faster than the other said motor (68) and for slowing the rotation of the faster-running motor so that it substantially equals the rotation of the slower-running motor.

14. A table according to Claim 13, wherein each said drive means includes means (97,126) for sensing and counting the rotation of rotatable output members associated with the pair of motors (68) so as to determine a height value for the top assembly, and display means (132) for visually displaying the height of the top assembly.

15. In an adjustable work station including means defining separately movable front and rear height-adjustable support surfaces (27,46) which are respectively adapted to support thereon a keyboard and an associated information display screen, and drive means (51,52) cooperable with said support surfaces for adjusting them to a desired relative height arrangement wherein said front support surface is disposed at a first height and said rear support surface is disposed at a second height, the improvement comprising:
height determination means (126) for determining a pair of first and second height values which respectively correspond to the first and second heights at which said support surfaces are currently disposed;
storage means (91, 115) for uniquely identifying and storing a plurality of said height value pairs which correspond to various possible relative height arrangements of said support surfaces;

display means (92) responsive to a predetermined user input for retrieving a selected one of said height value pairs from said storage means and producing a visual display of said selected height value pair; and automatic adjustment means (91,115) responsive to a predetermined user input for automatically adjusting said front and rear support surfaces to a relative height arrangement wherein said support surfaces are disposed at the respective heights represented by the corresponding height value of the selected height value pair.

16. A work station according to Claim 15, wherein said automatic adjustment means, in response to said predetermined user input, includes means for first vertically moving said rear support surface (46) to the height corresponding to the rear height value of the selected height value pair, and for then automatically thereafter moving the front support surface (27) to the height corresponding to the front height value of the selected height value pair.

17. A work station according to Claim 16, wherein said automatic adjustment means includes means for admitting a visual and/or audible warning after: receipt of said predetermined user input but prior to initiation of the movement of rear support surface, and said means also emitting a visual and/or audible warning after said rear support surface has reached its respective height but prior to initiating the movement of the front support surface.

18. A work station according to Claim 15, wherein said drive means includes rotatable electric motor means (68), and said height determination means including means (126) for sensing and counting the rotations of said rotatable output member so as to determine said height values.

19. A work station according to any one of Claims 15-18, including:
timer means (128) for measuring elapsed time and indicating that a predetermined amount of time has elapsed;
sequencing means for storing a defined sequence of work station events with each event being defined by one of the previously stored height value pairs in combination with a selected time interval; and said automatic adjustment means including means (127) for automatically adjusting said front and rear support surfaces sequentially according to the height values and time intervals defined by the sequential events in response to a predetermined user input prior to initiation of each said event.

20. A work station according to Claim 19, wherein said automatic adjustment means includes means for emitting a visual and/or audible warning after receipt of said predetermined user input but prior to initiation of the movement of the rear support surface, and said means also emitting a visual and/or audible warning after said rear support surface has reached its respective height but prior to initiating the movement of the front support surface.

21, A work station according to Claim 15, including right and left telescopically extendible and contractible leg assemblies (45) connected to and projecting downwardly from each of said support surfaces, said drive means (51) including separate right and left drives respectively associated with each of said right and left leg assemblies for controlling vertical extension and contraction thereof to adjust the height of the respective support surface, each said right and left drive respectively including right and left electric motors (68), and control means (126) for causing synchronous rotation of the right and left motors associated with the respective support surface and for automatically adjusting one of said motors relative to the other to substantially equalize vertical displacement of the right and left leg assemblies of the respective support surface.

22. A work station according to Claim 21, wherein the height determination means includes means for sensing and counting the rotations of the rotatable output member so as to determine the height values, and the control means includes means for sensing when one of the right and left motors is rotating faster than the other of aid right and left motors and for adjusting the speed of at least one of the motors so as to substantially equalize the rotation of the right and left motors.

23. In a table having a horizontally enlarged top (12,13) defining thereon a horizontally enlarged and upwardly facing work surface, a pair of vertically elongate leg assemblies (45) connected to said top at sidewardly spaced locations and projecting downwardly therefrom for supporting the top at selected heights above a support surface, each said leg assembly including a top leg (37) fixed to and projecting downwardly from the top and being vertically slidably supported on a lower leg (19) for permitting adjustment in the height of the top, and a powered drive arrangement drivingly coupled to said pair of leg assemblies for permitting powered vertical displacement of said top legs to adjust the height of said top, comprising the improvement wherein:
said drive arrangement includes a pair of powered drive means (51) each associated with a respective one of said leg assemblies, each said drive means including a low-voltage direct current electric motor (68) drivingly coupled to a rotary input of a rotary-to-linear motion converter means (52) having a linearly-movable output coupled to one of said legs for effecting vertical extension and contraction of said leg assembly, the rotary-to-linear motion converter associated with each said leg assembly being free of mechanical driving connection with the motion converter of the other said leg assembly, said pair of powered drive means being operatively coupled together solely by electrical cable means for transmitting electrical energy between said motors; and controller means (92) for simultaneously controlling the rotation of the motors (68)) of said pair of drive means for synchronizing the extension and contraction of said pair of leg assemblies, said controller means include means (126) for sensing when one said: motor is rotating faster than the other said motor and for slowing the rotation of the faster-running motor so that it substantially equals the rotation of the slower-running motor.