Patent GB-1443082-A (GB)
Title: Device for controlling a lift with a speed-regulated drive
IPC: B66B1/16
Filed: 1974-02-13
Abstract: 1443082 Automatic elevator car speed control INVENTIO AG 13 Feb 1974 [18 April 1973] 06470/74 Heading B8L In a lift control system, Fig. 1 (not shown), the car is accelerated as a function of time under control of pattern voltage USb towards a maximum speed V max, there being generated, in a time sequence and for each floor ahead of the car, a deceleration pattern voltage USv, dependent on distance, the first such voltage commencing at the time of car departure. When the difference USv - USb decreases to a predetermined value URG2, the next deceleration pattern voltage is selected provided no call is required at the destination appertaining to the current pattern voltage, otherwise the latter is retained, and, when USv and USb are substantially equal, control of the car drive is changed, with allowance for rounding off, e.g. R2, from dependence on USb, to dependence on the appropriate USb. Maximum speed Vmax is not attained for shorter journeys. The pattern voltage USb representing constant acceleration of magnitude set by (PT1) Fig. 5 (not shown) is provided to the output (7À5) of pattern voltage generator (7) by charging capacitors (CT2, CT1) via constant current transistor source (TT1, PT2, ZT), the maximum charge, corresponding to maximum speed, being set at (PT3). The deceleration pattern voltages USv are provided, by subtracting, from the voltage waveform, Fig. 6, with step-wise increments USV1, USV2 etc.; the size of individual steps corresponding to the distances between succeeding floors; the waveform being provided by unit (9À1), Fig. 3 (not shown), relays (SVK1, SVK2) &c. therein closing in sequence, the integrated output UI, from integrator (I), of an actual velocity signal from a tachogenerator the integrator, by means of contacts (S1K1-S1K3) being reset to zero each time the car passes a floor, and taking the root of the result by means of circuit (7À2, Fig. 5) comprising an amplifier with non-linear feedback. Comparator (OG2, Fig. 5) compares USb with the current USv less URG2, the voltage across resistor (RG2) in series with constant current source (TG2, ZG, PG1) and, at equality, enables nor (NL), provided deceleration command (LH) is absent, which via units (11, 10), Fig. 1 (not shown) provides a signal (LS1) or (LS2) &c. Fig. 3 (not shown), to close the succeeding relay contact (SVK1, 2 &c.) to step up the voltage USV. Contacts (SVK1-SVK2 &c.) are opened again under control of signals (LM1, 2 &c.) when the car passes the appropriate floor. Should nor (NL) not be enabled, comparator (OG1), when USb=USv, operates relay coil (SG), contacts (SGK) closing to couple the current deceleration signal USv to the pattern generator output (7À5). At the approach to a destination floor, integrator (I) is set to zero, P, Fig. 6, in advance of the floor being reached, a landing voltage USE being supplied by closure of contacts (SEK, Fig. 3), the car stopping when USE and the integrator output subtract to zero. The pattern generator output, via direction switching arrangement (8, Fig. 1) is fed to the regulating arrangement (5) of the retroactive car drive including motor (3) and tachogenerator (6).