baber/WOPTO huggingface dataset:
Patent FR-2434331-A1 (FR)
Title: Tube de canalisation isole thermiquement
IPC: B29C63/18
Filed: 1978-12-21
Abstract: a. Tube de canalisation composé de deux tubes concentriques pourvus entre eux d'un entretoisement. b. L'invention consiste essentiellement en ce que, dans l'entretoisement, en polyuréthane dur, prévu entre les deux tubes concentriques, sont ménagées des entailles en forme de V, l'espace restant entre les tubes étant rempli de matière plastique expansée à base de polyuréthane. L'invention vise également un procédé de fabrication en continu de l'entretoisement en question. c. L'invention trouve son application principale dans les tubes de canalisation.
Patent FR-2445161-A1 (FR)
Title: Toy to simulate driving vehicle - has cross bar with wheels guided by steering wheel on vertical bar
IPC: A63H33/00
Filed: 1978-12-29
Abstract: The toy allows a child to pretend that he is driving a vehicle. It has a cross bar (1) with small wheels (7, 8) at each extremity (5, 6) which are carried on axles (3, 4) fitted in bearings (9, 10) fixed under the bar. A steering wheel n15) is fixed to one extremity of a rod (14) which can rotate with regard to the cross bar. Above the centre of the cross bar a support (11) is fixed for a pin (12) at right angles to the axis of the cross bar. The pin is fitted into the other extremity of the rod and is perpendicular to its axis.
Patent FR-2446220-A1 (FR)
Title: Reaction drive engine for boat - has cam operated pistons acting directly towards the stern and sealed with bellows vented to the inside of engine
IPC: B63H1/32
Filed: 1979-01-11
Abstract: The engine consists of units each comprising a cam (9) which drives a spring loaded follower (2). The follower is attached to a piston (1) with a concave crown. The sides of the piston are sealed with bellows (7) and the space enclosed by the piston and bellows is vented to the cam chamber through vent holes (5). The vessel may be steered by unloading the pistons on one side of the hull, by maintaining the return spring compressed and isolating the drive from the cam.
Patent FR-2417520-A1 (FR)
Title: Film d'alcool polyvinylique etire biaxialement de facon simultanee
Inventor: KUGA MUTSUO
IPC: C08J7/048
Filed: 1979-02-14
Abstract: Procédé pour préparer un film en alcool polyvinylique étiré biaxialement de façon simultanée. Il comporte l'enduction d'une dispersion aqueuse d'un composé macromoléculaire, au moins sur une surface d'un support constitué par un film d'alcool polyvinylique non-orienté, puis l'exposition du film à un étirage biaxial simultané suivant un allongement en pourcentage élevé, à un sèchage sous relaxation de tension et à un traitement à chaud. Emballages alimentaires notamment
Patent FR-2454259-A1 (FR)
Title: Hedge cutter guide trolley - comprises tubular structure on caster wheels with horizontal and vertical cutter guides
IPC: A01G3/04
Filed: 1979-04-17
Abstract: The guide trolley is for use when cutting hedges, and comprises a tubular structure on four caster wheels. One part (J) hinges on an axis (A) and is held open during use by a strut (B). A guide (D) moves on the face of the trolley in the lengthwise direction on two slides (E,F), and supports a further guide (C) for the hedge-cutter (TH), movable up and down on it for its full height. The lower part of the guide (D) can be fixed to a slide (G) movable forwards and rearwards to level the cutter. Guide (E) can be of round and guide (F) of square tube, and the rear wheels (H) can be adjustable for height.
Patent FR-2422655-A1 (FR)
Title: Nouveaux derives nitrosouree des gentiobioses et leur application dans le traitement des affections leucemiques et tumorales
IPC: A61P35/00
Filed: 1979-04-13
Abstract: Ces dérivés nouveaux de la nitrosourée ont comme formule de structure commune :
Patent FR-2457692-A1 (FR)
Title: Living virus culture vaccine against canine distemper - comprising attenuated strain epm. 10-76 obtd. from mink having distemper
Inventor: DOROFEEV VIKTOR MATVEEVICH
IPC: A61K39/175
Filed: 1979-05-29
Abstract: Living virus culture vaccine against canine distemper comprises an attenuated strain EPM No. 10-76 obtd. from the wield virus. It is isolated from a mink having distemper by multiple passage of the virus on (1) dog kidney cell culture, (2) continuous cell culture of the kidneys of the human embryo Rh and (3) mixed culture of dog kidney cells and Japanese quail embryo cells, adapted to the Japanese quail embryo cell culture and grown on this cell culture. The vaccine is harmless, it does not produce toxic effects on admin. and it is obtd. economically. The vaccine has high antigenic activity, it produces effective and persistent immunity in treated animals and vaccination in the epizootic foci of canine may be distemper rapidly eradicates infection. The vaccine may be given parenterally or in aerosol form, and since it is highly active, the amts. required for 1-500 doses can easily be filled into vials.
Patent FR-2459962-A1 (FR)
Title: Hot wire gas flow detector - contains comparator and amplifier in servo loop to maintain temp. constant and can measure low flow rates
Inventor: MAILLOT JEAN-PIERRE
IPC: G01F1/698
Filed: 1979-06-25
Abstract: The hot wire gas flow detector is used to measure low flow rates such as for artificial breathing. The gas has a variable temp. and may be saturated with humidity. A hot platinum wire (1) is located in one arm of a Wheatstone bridge containing three other resistors (2,3,4). The junction of the hot wire with the resistor (2) and the junction between the other two resistors are applied to a comparator (5) input. The comparator output drives an amplifier (6) which forms a servo loop to maintain the hot wire temp. constant in the presence of the gas flow. The voltage across the hot wire element is measured to provide an indication of the gas flow.
Patent FR-2461142-A1 (FR)
Title: Holding down bolt for plastics - has shank with two radial necked step reductions and coarse thread on upper two zones, to be pressed into heated bore
IPC: F16B37/12
Filed: 1979-07-12
Abstract: The holding down bolt is for plastics material (9), with an embedded shank (2) with radial steps reducing the diameter towards the foot of a preliminary bore. A cylindrical body (1) projects above the plastics, defined by a circumferential flange (7). The flange (7), a top shank zone (5), an intermediate shank zone (4), and a basal shank zone (3) are separated by rectangular section grooves (6). The top two zones (5,4) have inverse coarse spiral threads. The base zone diameter corresponds to that of the bore, and a flat (8) on the shank zone is tangential to the base zone (3). Longitudinal grooves may be used in lieu of flats (8), and the bolt may be forced into place as heat is applied to the plastics material.
Patent FR-2433028-A1 (FR)
Title: Hydrocarbyl-poly (oxyalkylene) aminocarbamates et leur application comme additifs pour carburants et lubrifiants
IPC: C10M149/14
Filed: 1979-08-01
Abstract: L'invention concerne des compositions de carburants pour moteurs à combustion interne. Ces carburants sont additionnés d'hydrocarbylpoly-(oxyalkylène) aminocarbamates comprenant un groupement poly-(oxyalkylène) à terminaison hydrocarbylique composé d'unités oxyalkylène à 2-5 atomes de carbone et de groupes oxyalkylène à 9-30 atomes de carbone. Ces additifs empêchent la formation de dépôts dans les systèmes d'admission et servent aussi d'agents dispersants pour des huiles lubrifiantes.
Patent FR-2433247-A1 (FR)
Title: Connecteur electrique a force d'insertion nulle
IPC: H01R24/00
Filed: 1979-08-06
Abstract: Connecteur électrique à force d'insertion nulle. La présence de nombreux patins conducteurs sur le bord d'une plaquette à circuits imprimés à raccorder nécessite une grande force pour insérer la plaquette dans un connecteur et l'en extraire. La plaquette risque d'être abîmée par suite de sa cambrure, et la réduction de la pression de contact empêche un raccordement sûr. Le connecteur selon l'invention évite ces inconvénients et comporte une base en isolant avec une pluralité de contacts, chaque contact ayant une partie de raccordement en saillie sur la surface inférieure et une partie de contact en saillie sur la surface supérieure Un corps d'engagement de contacts isolé enferme les parties de contact des contacts et comporte une ouverture recevant l'organe d'insertion mâle. Le corps peut être rapproché et éloigné de la base et comporte des surfaces à effet de came venant toucher les extrémités de contact Le connecteur comprend en outre un dispositif d'actionnement pour animer d'un mouvement de va-et-vient le corps par rapport à la surface supérieure de la base et amener chaque contact à toucher un élément conducteur correspondant de l'organe d'insertion mâle. Application aux connecteurs électriques.
Patent FR-2463720-A1 (FR)
Title: Pedal operated single seat vessel - has paddle wheel connected to crank with rudder with yoke and saddle for the crew support
IPC: B63H16/20
Filed: 1979-08-17
Abstract: The float has a plastics frame (1) with buoyancy, which is in two parts. The rear has a saddle and supports the rudder (4). The position of the rear part can be adjusted on the forward part (3). This carries the driving wheels (5). The drive consists of a pedal crank (7) and two paddle wheels (5), fitted with vanes. The crew lies on the saddle and steers by holding onto the yoke, on either side of the rudder.
Patent FR-2434768-A1 (FR)
Title: Conteneur plateforme
IPC: B65D19/12
Filed: 1979-08-28
Abstract: La présente invention concerne un conteneur plateforme constitué d'un plancher et de deux parois d'extrémité. Ce conteneur est caractérisé par le fait que le dispositif de verrouillage est constitué d'au moins une clavette 44 qui, lorsque la paroi d'extrémité 14, 18 est relevée, peut être introduite dans un évidement 50 de cette paroi de façon à verrouiller et serrer cette dernière et le plancher 12 l'un par rapport à l'autre. Applicable au transport de marchandises.
Patent FR-2437355-A1 (FR)
Title: Distributeur pour produits liquides, pateux ou pulverulents, en particulier pour soins corporels
IPC: B65D83/00
Filed: 1979-09-17
Abstract: DISTRIBUTEUR POUR PRODUITS LIQUIDES, PATEUX OU PULVERULENTS, EN PARTICULIER POUR SOINS CORPORELS. DISTRIBUTEUR COMPRENANT UN RESERVOIR 1 MUNI D'UNE TETE DE DISTRIBUTION 3 ET D'UN TUBE DE DISTRIBUTION 4 MOBILE ENTRE UNE POSITION DE FERMETURE ET UNE POSITION D'OUVERTURE. IL COMPREND UN TUYAU FLEXIBLE 10 RELIANT DE FACON ETANCHE LA TETE 3 AU TUBE DE DISTRIBUTION 4, CE TUYAU FLEXIBLE ETANT PINCE, EN POSITION DE FERMETURE ENTRE UNE PARTIE DU TUBE 4 ET DE LA TETE 3 DE TELLE SORTE QUE LE DISTRIBUTEUR EST FERME DE FACON ETANCHE. POUR PRODUITS LIQUIDES, PATEUX OU PULVERULENTS, EN PARTICULIER LIQUIDES ET CREMES POUR SOINS CORPORELS.
Patent FR-2437555-A1 (FR)
Title: Distributeur de commande equipe d'un joint annulaire d'etancheite d'un intervalle radial, notamment pour direction assistee
IPC: B62D5/097
Filed: 1979-09-28
Abstract: DISTRIBUTEUR DE COMMANDE EQUIPE D'UN JOINT ANNULAIRE D'ETANCHEITE. LEDIT DISTRIBUTEUR, COMPORTANT UN OU PLUSIEURS TIROIRS ROTATIFS, COMPORTE UN JOINT 16 ANNULAIRE DOTE D'UNE BAGUE D'APPUI EN MATIERE RIGIDE INTERCALEE ENTRE UN PALIER DE BUTEE 18 DU CORPS 2 ET LE OU LES TIROIRS ROTATIFS 6, 10. CETTE BAGUE D'APPUI, QUI ENTOURE L'ARBRE 12 ET PEUT SE DEPLACER SOLIDAIREMENT AVEC LUI DANS UN MOUVEMENT RADIAL A L'INTERIEUR DU CORPS, PRESENTE DEUX EVIDEMENTS DESTINES A FORMER DEUX ESPACES ANNULAIRES DANS CHACUN DESQUELS EST LOGEE UNE BAGUE D'ETANCHEITE PRECOMPRIMEE, SOIT RADIALEMENT, SOIT AXIALEMENT. APPLICATION AUX MECANISMES HYDROSTATIQUES DE DIRECTION ASSISTEE.
Patent FR-2467067-A1 (FR)
Title: Dispositif pour la fabrication de corps a structure alveolaire par extrusion d'une matiere ceramique, et procede d'obtention dudit dispositif
Inventor: MINJOLLE LOUIS
IPC: B29C48/11
Filed: 1979-10-15
Abstract: L'invention concerne la fabrication de corps à structure alvéolaire par extrusion d'une matière céramique. Le dispositif selon l'invention est remarquable par le fait qu'il est essentiellement conçu en une succession d'éléments coaxiaux emboîtés les uns autour des autres, que deux éléments adjacents définissent entre eux des canaux longitudinaux débouchant en leur extrémité aval dans un canal annulaire, et que lesdits éléments coaxiaux emboîtés présentent, inférieurement et au niveau des canaux annulaires, des encoches essentiellement rayonnantes et de la largeur inférieure à la largeur des canaux longitudinaux, de sorte que la matière céramique s'écoulant par lesdits canaux longitudinaux soit régulièrement répartie dans les canaux annulaires et les encoches rayonnantes pour former directement à l'extrusion un corps à structure alvéolaire. Application aux structures céramique en nid d'abeilles à parois minces. (CF DESSIN DANS BOPI)
Patent FR-2457893-A1 (FR)
Title: Culture du genre streptomyces, utilisable notamment pour la preparation d'antibiotiques
Inventor: DEUSHI TAKEO
IPC: C07H15/224
Filed: 1980-01-17
Abstract: CULTURE BIOLOGIQUEMENT PURE DE STREPTOMYCES SP. KC-7038 DONT LES CARACTERISTIQUES SONT CELLES DE LA SOUCHE IDENTIFIEE SOUS LE N FERM-P 4388 ET SOUS LE N ATCC 31530, ET POUVANT PRODUIRE LA SUBSTANCE ANTIBIOTIQUE KA-7038 PAR FERMENTATION DANS UN MILIEU DE CULTURE CONTENANT UNE SOURCE DE CARBONE, UNE SOURCE D'AZOTE ET DES SUBSTANCES MINERALES.
Patent FR-2478380-A1 (FR)
Title: Coupling for VHF aerials mounted on same pylon - has quarter wavelength radius conducting disc mounted on pylon between transmitter and receiver aerials
Inventor: HILLION HERVE
IPC: H01Q1/52
Filed: 1980-03-14
Abstract: The aerials are mounted on the one pylon at different heights and have a decoupling coefficient of 70 dBs, operating in the range of 150-220 MHz. A decoupler, in the form of two conductor discs, is located midway between the two aerials. The discs are mounted coaxially, with each disc having a radius of a quarter wavelength. The discs are spaced apart by a quarter wavelength distance and the aerial is equidistant from the pylon foot and the discs. The discs have a thickness of 4mm. The aerials are pref. half-wavelength dipoles, each having two back-to-back reflector screens.
Patent FR-2478884-A1 (FR)
Title: Male coaxial plug - has machined shell and pin which clip over and inside plastics separator locked by plastics split ring or resin fill
Inventor: CARRIERE JEAN
IPC: H01R13/646
Filed: 1980-03-18
Abstract: The connector for high frequency transmission of signals, is mfd. from a small number of interlocking parts, the metal parts being capable of being produced by an automatic lathe. The device consists of an external metal shell which is flared internally at the mating end. An insulating plastics separator clips inside the shell by a collar. The separator has a shoulder midway and a bulkhead separating the front of the connector from the cable end. The separator is also flared internally at the mating end. A central pin inserted through a hole in the bulkhead with the operation is facilitated by making the rings which lock the stem in place conical. Once clipped into place the assembly may be locked by a plastics split ring between the separator and the rear stem of the central pin. The back of the connector may be filled with a resin, the outer shell being grooved to improve the anchorage of the resin.
Patent FR-2478973-A1 (FR)
Title: Flexible hose attachment for hair-dryer - comprises two spaced coaxial corrugated tubes joined at their end by two rings
Inventor: QUESSARD ROLLAND E
IPC: A45D20/52
Filed: 1980-03-26
Abstract: The hose attachment extending between the hot air outlet and the vicinity of the hair, has a directional nozzle attached to its free end. It comprises two coaxial tubes with the hot air fed through the innermost tube and with a narrow gap between the two tubes which are joined together by two rings at their ends. Both tubes are pref. made of a heat-resistant material with poor thermal conduction characteristics, so that the outer tube does not become too hot to touch. Each tube is corrugated along its entire length, with the corrugations of the outer tube being spaced closer together than those of the inner tube. The attachment prevents the hair dryer having to be held during drying and allows it to be placed on a fixed surface or attached to a fixed support.
Patent FR-2480362-A1 (FR)
Title: Electromagnetic pump for liquid - has magnet core connected via insulator to move diaphragm of variable volume compression chamber
Inventor: JANVIER MARTIAL
IPC: F04B43/04
Filed: 1980-04-14
Abstract: The electromagnetic pump includes an inlet and an outlet pipe connected to a compression chamber via respective non-return valves. The volume of the compression chamber is determined by the position of the elastic membrane which forms a seal between the chamber and the operating electromagnet. The electromagnet includes coils and a moving core, the core being attached via a non-conducting tapered rod to the pump membrane. When the electromagnet is operated the core moves, also moving the membrane to operate the pump. When the current to the electromagnet is interrupted, the core is moved in the opposite axial direction by a return spring. The non-conducting tapered rod ensures that there is no electrical contact between the liquid and the electromagnet assembly.
Patent FR-2457032-A1 (FR)
Title: Dispositif de graissage differe pour machines electriques
Inventor: HAGENLOCHER WALTER
IPC: H02K5/173
Filed: 1980-05-14
Abstract: A.DISPOSITIF ASSURANT UN GRAISSAGE DIFFERE AUTOMATIQUE DE PALIERS A ROULEMENT OU AUTRES. B.CE DISPOSITIF DE GRAISSAGE DIFFERE COMPORTE UN RESERVOIR D'ALIMENTATION EN LUBRIFIANT SUPPLEMENTAIRE, CONSTITUE PAR UN ELEMENT 15 EXERCANT SUR LE LUBRIFIANT 16 UNE PRESSION DEPENDANT DE LA TEMPERATURE DU PALIER 12, DE TELLE SORTE QUE LORSQUE CETTE TEMPERATURE S'ELEVE, L'ELEMENT 15 - PAR EXEMPLE UN TUBE SOUPLE RETRACTABLE - DIMINUANT DE VOLUME, LE LUBRIFIANT EN RESERVE 16 EST REFOULE DANS LE PALIER 12. C.L'INVENTION S'APPLIQUE NOTAMMENT AUX PALIERS A ROULEMENT UTILISES DANS LES ALTERNATEURS TRIPHASES DE VEHICULES AUTOMOBILES.
Patent FR-2482856-A1 (FR)
Title: Non-irritating seat for invalid chair - has fibre cushion carrying perforated layer and supported by perforated rigid shell
Inventor: RABISCHONG PIERRE
IPC: A61G7/057
Filed: 1980-05-22
Abstract: The seat for an infirm person is suitable for use with a wheelchair, in particular for paraplegics, and is designed to prevent irritation of the skin. A cushion (6) with a suitably shaped upper surface (6a) is supported by an open fronted tray (1) made of rigid material, and with a pattern of holes (3) through its base sheet (2). On top of the cushion is a thinner resilient layer (8) also with a pattern of holes (9) through it. The cushion has an outer covering (7) of natural fibres, pref. a spongy material, enclosing a core made of a mixture of fibres, pref. animal or vegetable fibres, and an elastomeric binder. Another design has a cushion with two separate layers enclosed by a removable cover, the whole being washable.
Patent FR-2483214-A1 (FR)
Title: Implant for osteosynthesis of femoral head - has diaphysial plate extended above inclined blade to accommodate screws passing through blade
Inventor: PRUDHOMME JEAN-FRANCOIS
IPC: A61B17/74
Filed: 1980-05-30
Abstract: The osteosynthesis equipment is for the neck of the femur, comprising a diaphysial plate (2) and a blade (3) extending at least part-way through the neck. The plate has a screw (6) which engages the femoral neck. The plate has an extension (4) extending above the blade to form a Y-shaped unit. Several holes (9,10) are drilled in the extension for screws (11,12) passing through holes (7,8) formed in the blade. The screws bear against the edges of these holes, forming with the blade a rigid triangular structure for the fractured portions of the neck of the femur.
Patent FR-2484125-A1 (FR)
Title: Dispositif de cloisonnement du coeur d'un reacteur nucleaire
Inventor: LEROY JEAN-LUC
IPC: G21C5/10
Filed: 1980-06-06
Abstract: L'INVENTION CONCERNE UN DISPOSITIF DE CLOISONNEMENT DU COEUR D'UN REACTEUR NUCLEAIRE. LE CLOISONNEMENT COMPORTE DES PLAQUES 17 FIXEES SUR L'ENVELOPPE 8 DU COEUR DISPOSEES TRANSVERSALEMENT PAR RAPPORT AUX ASSEMBLAGES 5 ET DES PLAQUES 19 DE DIRECTION LONGITUDINALES. LES PLAQUES LONGITUDINALES 19 SONT DISPOSEES DANS LES ESPACES MENAGES ENTRE LES PLAQUES TRANSVERSALES 17 ET LEGEREMENT EN RETRAIT PAR RAPPORT AUX ASSEMBLAGES 5. LES PLAQUES 17 SONT RELIEES AUX PLAQUES 19 AVEC UN CERTAIN JEU DANS LA DIRECTION LONGITUDINALE. LES PLAQUES 17 SONT EN CONTACT AVEC LES ASSEMBLAGES 5 DISPOSES A LA PERIPHERIE DU COEUR PAR L'INTERMEDIAIRE D'UNE PARTIE DE LEUR SURFACE PERIPHERIQUE. L'INVENTION S'APPLIQUE, EN PARTICULIER, AUX REACTEURS NUCLEAIRES A EAU SOUS PRESSION.
Patent FR-2460426-A1 (FR)
Title: Transmission control for excavator vehicle - has automatic control of stepped gearing when vehicle direction is reversed
Inventor: OPPERUD HANS-JORGEN
IPC: F16H61/02
Filed: 1980-06-27
Abstract: The transmission control uses a torque converter and a stepped gearing, controlled automatically in dependence on the engine parameters, e.g. the engine revs and torque and also in dependence on the position of a manual gear selector. A signal representing the required direction of rotation of the take-off shaft is supplied in dependence on whether forwards or reverse drive is selected. When this signal alters, to indicate the opposite sense of rotation to the current rotation, the operation of the stepped gearing is controlled so that the rotation of the take-off shaft is retarded, while the vehicle is slowed down. Pref. the operation of the gearing control for retarding the take-off shaft is delayeduntil the vehicle speed drops below a given value.
Patent FR-2460954-A1 (FR)
Title: Procede de production de l'acide 7-(2- aminomethylphenylacetamido)-3- (1-carboxymethyltetrazol-5-ylthiomethyl)-3-cephem-4-carboxylique
Inventor: LIM GARY M F
IPC: C07D501/36
Filed: 1980-07-02
Abstract: L'INVENTION CONCERNE UN PROCEDE DE PRODUCTION DE L'ACIDE 7- (2-AMINOMETHYLPHENYLACETAMIDO)-3- (1-CARBOXYMETHYLTETRAZOL-5-YLTHIOMETHYL)-3-CEPHEM-4-CARBOXYLIQUE. CE COMPOSE EGALEMENT APPELE CEFORANIDE EST PRODUIT PAR REDUCTION EN SOLUTION AQUEUSE D'UN SEL HYDROSOLUBLE D'ACIDE 7- (2-AZIDOMETHYLPHENYLACETAMIDO)-3- (1-CARBOXYMETHYLTETRAZOL-5-YLTHIOMETHYL)-3-CEPHEM-4-CARBOXYLIQUE EN UTILISANT UN COMPLEXE DE BORANE ET D'UNE AMINE ET LE NICKEL DE RANEY COMME CATALYSEUR. LE CEFORANIDE EST UN ANTIBIOTIQUE INJECTABLE PUISSANT, DE LA FAMILLE DES CEPHALOSPORINES.
Patent FR-2487803-A1 (FR)
Inventor: SCHOUTEETEN ROBERT
IPC: B66F7/04
Filed: 1980-07-31
Abstract: A lifting device, in particular a lifting platform, has a vertically movable platform (5) which is supported by ropes (12) and guided in columns (1, 2, 3 and 4). A control device (20, 21, 15) serves for lifting the platform and a control device (26, 28) for lowering the platform. At least one scanning element (36) is provided which interacts with the ropes for checking the tension. A catch device (31, 33) blocks the platform when it is lowered in the case of abnormal tension in at least one of the ropes. In order to be able to actuate the lifting device in the case of a slack rope but to make the actuation of the lifting device impossible in the case of breakage of a rope, the scanning device (36) is connected to a device for controlling the blocking of the control means for the lowering of the platform (5) in the case of discovery of an abnormal tension in at least one of the ropes (12), which tension does not exceed a particular value. Additionally, the scanning device (36) is connected to a device for controlling the blocking of the control device (20, 21, 15) for lifting the platform if the tension in one of the ropes (12) rises abnormally above the predetermined value.