WO2004034945A1 - An electrical drive system - Google Patents

An electrical drive system Download PDF

Info

Publication number
WO2004034945A1
WO2004034945A1 PCT/DK2003/000710 DK0300710W WO2004034945A1 WO 2004034945 A1 WO2004034945 A1 WO 2004034945A1 DK 0300710 W DK0300710 W DK 0300710W WO 2004034945 A1 WO2004034945 A1 WO 2004034945A1
Authority
WO
WIPO (PCT)
Prior art keywords
conductors
actuator
hand control
signal
cable
Prior art date
Application number
PCT/DK2003/000710
Other languages
French (fr)
Inventor
Jeppe Christian Bastholm
Original Assignee
Linak A/S
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linak A/S filed Critical Linak A/S
Priority to EP03757730A priority Critical patent/EP1553907A1/en
Priority to AU2003273773A priority patent/AU2003273773A1/en
Publication of WO2004034945A1 publication Critical patent/WO2004034945A1/en

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/50Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
    • G01R31/52Testing for short-circuits, leakage current or ground faults
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61GTRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G7/00Beds specially adapted for nursing; Devices for lifting patients or disabled persons
    • A61G7/002Beds specially adapted for nursing; Devices for lifting patients or disabled persons having adjustable mattress frame
    • A61G7/018Control or drive mechanisms
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/28Testing of electronic circuits, e.g. by signal tracer
    • G01R31/282Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
    • G01R31/2829Testing of circuits in sensor or actuator systems

Definitions

  • the present invention relates to an electrical drive system comprising at least an actuator, a control unit connected to the actuator, a hand control connected to the control unit by a multi-core hand control cable with a common conductor as well as a plurality of individual conductors., said hand control comprising a plurality of function keys connected to the common conductor and to individual conductors for the control of the actuators.
  • Such a drive system is generally incorporated in adjustable articles of furniture, and by way of example reference is made to EP 498 111 B1 and EP 488 552 both to J. Nesbit Evans & Company Limited, which together describe a hospital bed where the mattress support as a whole may raised/lowered as well as be tilted about a transverse axis and additionally be profiled by rotation of the backrest and the legrest.
  • the patient can operate the bed by a hand control connected to the control unit by a cable.
  • the hand control cable which must necessarily be of a certain length, is liable to be damaged because it may accidentally be jammed at the mov- able parts in the bed. Complete cutting/tearing of the cable is annoying, of course, but involves no immediate danger to the patient, which may be the case by partial damage where some of the conductors in the cable are short-circuited. Such a type of damage is not always visible on the external sheath of the cable, but the insulation around the individual conductors may very well have been stripped. If the patient wants to adjust the backrest, then a damaged cable may e.g. cause the legrest to be activated at the same time, which may be a nuisance and at worst dangerous to the patient.
  • the object of the invention is to provide security against mis- adjustment for the user of the article of furniture, if the hand control cable is torn partly across and two or more conductors are short-circuited.
  • the drive system is provided with a signal generator which, in case of a current in the common conductor, because of activation of a function key on the hand control, transmits a signal (signals) through conductors in the hand control cable from one end of these, as well as a detector for detecting the signal at the other end of the conductors and adapted such that if one or more of predetermined conductors are short- circuited, it omits applying a signal (signals) to the control unit to activate the actuator or actuators concerned, in the alternative stops it or them, at least self-runners may be avoided and thereby critical situations. In a fur- ther development of the invention it is also possible to avoid some of the co-runners. An embodiment of the invention will be explained more fully below with reference to the accompanying drawing. In the drawing:
  • Fig. 1 shows a schematic diagram
  • fig. 2 shows a survey of short-circuit constellations in the hand control cable.
  • the diagram shown in fig. 1 just illustrates the parts necessary for the un- derstanding of the invention.
  • the common parts such as an actuators, power supply, etc., are omitted.
  • CB indicates a controller, K a hand control cable, and HB a hand control.
  • the control unit comprises four relays K1A, K1 B; K2A, K2B which in pairs control their respective actuators.
  • the cable comprises five conductors 1-5.
  • the hand control comprises four function keys 6, 7, 8, 9 connected to a common conductor 1 and by individual conductors 2-5 to the respective relays.
  • a current in the common conductor is detected by a detector 11 by means of the voltage drop across a pair of diodes.
  • the voltage drop across the pair of diodes is so small as to be insignificant relative to the structure in general.
  • the detector activates a pulse generator 12 which transmits pulses through the individual conductors 2-5, and the control unit includes another detector 13 to catch these signals.
  • the detector 13 in the control unit detects if one or more of the individual conductors are short-circuited with the common conductor.
  • the control unit is then adapted such that the motor relays K1A, K1 B; K2A, K2B are not activated, whereby the power to the motors is not turned on, or if the short-circuit occurs during running, then the relays are deactivated and the power to the motors is turned off, e.g. in that a FET in the control unit (the H-bridge to the motor) is connected to the detector 13 and is allowed to be turned on only when a signal is received from the signal generator as an indication of the cable being intact.
  • a short-circuit between the individual conductors 2 and 3 or 4 and 5 will draw both of the respective relays, and the non-activated actuator can thus not start.
  • the hand control cable may be damaged during running with an actuator in that it gets jammed, but the cable may also be damaged when the actuators stand still, e.g. in that a pull is applied to it, it gets jammed during transport, is run over, etc.

Abstract

In actuator systems which are operated via a cabled hand control, the problem may occur that an actuator accidentally starts running because of a short-circuit of conductors in the cable. Such actuator systems are used inter alia in hospital beds where such a 'self-runner' situation may be quite critical. Such situations may be prevented by arranging the system with a signal generator (12) which, in case of a current in a common conductor (1), transmits a signal through the conductors (2-5) in the hand control cable which is caught by a detector (13) at the other end of the conductors. Said system being adapted such that of one or more of predetermined conductors are short-circuited, it does not signal a control unit to activate the actuator or actuators concerned, alternatively stops it or them. A special embodiment may also allow for co-runner, i.e. where other actuators accidentally start running when an actuator is activated.

Description

An electrical drive system
The present invention relates to an electrical drive system comprising at least an actuator, a control unit connected to the actuator, a hand control connected to the control unit by a multi-core hand control cable with a common conductor as well as a plurality of individual conductors., said hand control comprising a plurality of function keys connected to the common conductor and to individual conductors for the control of the actuators.
Such a drive system is generally incorporated in adjustable articles of furniture, and by way of example reference is made to EP 498 111 B1 and EP 488 552 both to J. Nesbit Evans & Company Limited, which together describe a hospital bed where the mattress support as a whole may raised/lowered as well as be tilted about a transverse axis and additionally be profiled by rotation of the backrest and the legrest. The patient can operate the bed by a hand control connected to the control unit by a cable.
The hand control cable, which must necessarily be of a certain length, is liable to be damaged because it may accidentally be jammed at the mov- able parts in the bed. Complete cutting/tearing of the cable is annoying, of course, but involves no immediate danger to the patient, which may be the case by partial damage where some of the conductors in the cable are short-circuited. Such a type of damage is not always visible on the external sheath of the cable, but the insulation around the individual conductors may very well have been stripped. If the patient wants to adjust the backrest, then a damaged cable may e.g. cause the legrest to be activated at the same time, which may be a nuisance and at worst dangerous to the patient.
To avoid the hand control cable, research has been devoted to both infra- red and partly also radio-controlled remote controls, but these have other inherent drawbacks and problems, which means that wired hand controls are still preferred for adjustable articles of furniture.
Accordingly, the object of the invention is to provide security against mis- adjustment for the user of the article of furniture, if the hand control cable is torn partly across and two or more conductors are short-circuited.
According to the invention, the various situations are divided into the following categories:
1) "Self-runner" - a critical situation where other movable elements unintentionally begin moving, and which cannot be stopped once a function has been activated.
2) "Co-runner" - a non-critical situation where other movable parts, al- though they unintentionally begin moving, stop when the function key is released.
3) "Non-runner" - an inexpedient situation where a function cannot be activated.
When, according to the invention, the drive system is provided with a signal generator which, in case of a current in the common conductor, because of activation of a function key on the hand control, transmits a signal (signals) through conductors in the hand control cable from one end of these, as well as a detector for detecting the signal at the other end of the conductors and adapted such that if one or more of predetermined conductors are short- circuited, it omits applying a signal (signals) to the control unit to activate the actuator or actuators concerned, in the alternative stops it or them, at least self-runners may be avoided and thereby critical situations. In a fur- ther development of the invention it is also possible to avoid some of the co-runners. An embodiment of the invention will be explained more fully below with reference to the accompanying drawing. In the drawing:
Fig. 1 shows a schematic diagram,
fig. 2 shows a survey of short-circuit constellations in the hand control cable.
The diagram shown in fig. 1 just illustrates the parts necessary for the un- derstanding of the invention. The common parts, such as an actuators, power supply, etc., are omitted.
In the drawing CB indicates a controller, K a hand control cable, and HB a hand control. It is shown here that the control unit comprises four relays K1A, K1 B; K2A, K2B which in pairs control their respective actuators. The cable comprises five conductors 1-5. The hand control comprises four function keys 6, 7, 8, 9 connected to a common conductor 1 and by individual conductors 2-5 to the respective relays.
When a function key is operated to activate an actuator, a current in the common conductor is detected by a detector 11 by means of the voltage drop across a pair of diodes. The voltage drop across the pair of diodes is so small as to be insignificant relative to the structure in general. The detector activates a pulse generator 12 which transmits pulses through the individual conductors 2-5, and the control unit includes another detector 13 to catch these signals.
Taking the previously stated division of the various situations caused by a short-circuit between the conductors in the hand control cable as a basis, "self-runner" may occur because of a short-circuit of the individual conductors 2-5 with the common conductor 1. The detector 13 in the control unit detects if one or more of the individual conductors are short-circuited with the common conductor. The control unit is then adapted such that the motor relays K1A, K1 B; K2A, K2B are not activated, whereby the power to the motors is not turned on, or if the short-circuit occurs during running, then the relays are deactivated and the power to the motors is turned off, e.g. in that a FET in the control unit (the H-bridge to the motor) is connected to the detector 13 and is allowed to be turned on only when a signal is received from the signal generator as an indication of the cable being intact.
In a further development of the invention, some of the self-runner situations may moreover be detected and thereby be avoided. This applies where the individual conductors 4 or 5 are short-circuited with the individual conductor 2 or 3. For this purpose, the individual conductors 2-5 are connected to the detector 11 via a diode D.
A short-circuit between the individual conductors 2 and 3 or 4 and 5 will draw both of the respective relays, and the non-activated actuator can thus not start.
The various situations appear from the table shown in fig. 2.
As will be appreciated, it is not a question of localizing a defect in the hand control cable, but simply a question of detecting a defect on it at the moment when it occurs and responding to the defect. Alternatively, if the de- feet occurred during standstill, then detecting the defect the first time the hand control is used subsequently and responding to this defect. The cable may be damaged during running with an actuator in that it gets jammed, but the cable may also be damaged when the actuators stand still, e.g. in that a pull is applied to it, it gets jammed during transport, is run over, etc.
Although the invention has been described here in connection with a bed structure, it is evident that the invention is not restricted to this. In principle, the situation with a damaged hand control cable may occur in any structure, it might e.g. occur in a relaxer chair, a table, in an industrial application, etc.

Claims

Patent Claims
1. An electrical drive system comprising at least an actuator, a control unit (CB) connected to the actuator, a hand control (CB) connected to the control unit by a multi-core hand control cable (K) with a common conductor
(1) as well as a plurality of individual conductors (2-5), said hand control comprising a plurality of function keys (6-9) connected to the common conductor and to the individual conductors for the control of the actuators, characterized by a signal generator (12) which, in case of a current in the common conductor (1), because of activation of a function key (6-9) on the hand control (HB), transmits a signal through conductors (2-5) in the hand control cable (K) from one end of these, as well as a detector for detecting the signal at the other end of the conductors and adapted such that if one or more of predetermined conductors are short-circuited, it omits applying a signal (signals) to the control unit to activate the actuator or actuators concerned, in the alternative stops it or them.
2. A drive system according to claim ^characterized in that a current in the common detector is detected by a voltage drop across a pair of diodes (11).
3. A drive system according to claim 1 or 2, characterized in that the signal generator (12) is a pulse generator.
4. A drive system according to claim 2 or 3, characterized in that the individual conductors (2-5) are connected via a diode (D) to the detector (11).
PCT/DK2003/000710 2002-10-20 2003-10-20 An electrical drive system WO2004034945A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP03757730A EP1553907A1 (en) 2002-10-20 2003-10-20 An electrical drive system
AU2003273773A AU2003273773A1 (en) 2002-10-20 2003-10-20 An electrical drive system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DKPA200201596 2002-10-20
DKPA200201596 2002-10-20

Publications (1)

Publication Number Publication Date
WO2004034945A1 true WO2004034945A1 (en) 2004-04-29

Family

ID=32103850

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DK2003/000710 WO2004034945A1 (en) 2002-10-20 2003-10-20 An electrical drive system

Country Status (3)

Country Link
EP (1) EP1553907A1 (en)
AU (1) AU2003273773A1 (en)
WO (1) WO2004034945A1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3716876A (en) * 1971-05-20 1973-02-20 Sybron Corp Actuation means for an adjustable bed
DE3813883A1 (en) * 1988-04-25 1989-11-09 Lancier Masch Peter Measuring circuit for monitoring insulation resistances
US6008598A (en) * 1998-04-22 1999-12-28 Patmark Company, Inc. Hand-held controller for bed and mattress assembly
WO2000070796A1 (en) * 1999-05-17 2000-11-23 U.S. Electronics Components Corp. Remote control incorporating self test capability

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3716876A (en) * 1971-05-20 1973-02-20 Sybron Corp Actuation means for an adjustable bed
DE3813883A1 (en) * 1988-04-25 1989-11-09 Lancier Masch Peter Measuring circuit for monitoring insulation resistances
US6008598A (en) * 1998-04-22 1999-12-28 Patmark Company, Inc. Hand-held controller for bed and mattress assembly
WO2000070796A1 (en) * 1999-05-17 2000-11-23 U.S. Electronics Components Corp. Remote control incorporating self test capability

Also Published As

Publication number Publication date
AU2003273773A1 (en) 2004-05-04
EP1553907A1 (en) 2005-07-20

Similar Documents

Publication Publication Date Title
JP4160919B2 (en) Inverter device
KR940006837A (en) Electric vehicle controller
JP2001106446A (en) Safety circuit for elevator facility
WO2005108269A2 (en) Determining and handling brake failure in open loop variable frequency drive motors
KR101215509B1 (en) Control device for wind turbine brake
US6597138B2 (en) Method and apparatus for controlling power supplied to a motor
EP1553907A1 (en) An electrical drive system
JP2022551310A (en) Fault detection response in robot arm
JP4613200B2 (en) Method for operating a supply unit for a drive circuit and a supply unit for a drive circuit
JPH0723578A (en) Motor controller
JP4285832B2 (en) Grid interconnection inverter
JP2022042126A (en) Robot control device and robot system
EP0275633B1 (en) Control of multiphase ac motors
CN219164456U (en) Dual-motor driving circuit of storage bed
AU2001263933A1 (en) Drive unit comprising a device for the controlled and/or modulated gradual slow-down and shut-down of a funicular
JP2667710B2 (en) Industrial robot safety devices
EP1389355A1 (en) A device for drive equipment for adjustable furniture
JPH0759394A (en) Electric driving gear device
JP7198929B2 (en) How to test a robot arm for motor failure
WO2006032283A1 (en) Electrical actuator system
KR930020824A (en) Self-diagnosis method of inverter drive device
KR940020638A (en) PROTECTIVE IMPROVEMENTS IN INDUCTIVE COUPLING
JPH08265964A (en) Drive controller for single phase induction motor
JP2001037292A (en) Motor drive for furniture
JP3206692B2 (en) Runaway monitoring device for tap changer under load

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 2003757730

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 2003757730

Country of ref document: EP

NENP Non-entry into the national phase

Ref country code: JP

WWW Wipo information: withdrawn in national office

Country of ref document: JP