NO152873B - ANALOGUE PROCEDURE FOR PREPARING A THERAPEUTIC ACTIVE OCTAHYDRO-1H-PYRROLO (2,3-G) ISOKINOLINES - Google Patents

Abstract

ANALOGICAL PROCEDURE FOR PREPARING A. THERAPEUTIC ACTIVE OCTHYDRO-1H-PYRROLO [2,3-G] ISOKINOLINER. The present invention relates to an analogous process for the preparation of therapeutically active octahydro-1H-pyrrolo [2,3-g] isoquinolines of the general formula. wherein R 1 represents hydrogen, (C 1-4) alkyl, (C 1-6) alkanoyl, benzoyl or phenyl- (C 1-6) alkyl, R 2 is hydrogen, (C 1-4 alkyl, (C 1-4) alkenyl, (C 1-4) alkanoyl or phenyl - (C 1-4) alkyl, R 1-4 hydrogen, (C 1-6) -alkyl, (C 1-6) -cycloalkyl or phenyl, Rhydrogen, (C 1-6 -alkyl), (C 1-6 -hydroxyalkyl, 2,2-dimethyl-1,3- dioxolane-4-methyl, (C 1-4) alkoxy- (C 1-4) alkyl, (C 1-4) alkoxycarbonyl- (C 1-4) -alkyl, (C 1-6 -alkenyl, (C 1-6) -cycloalkyl- (C 1-6) -alkyl, thienyl- (C 1 -C 4) -alkyl, furyl- (C 1 -C 4) -alkyl, (C 1 -C 4) -alkanoyl- (C 1 -C 4) -alkyl, (C 1 -C 4) -alkenyloxy- (C 1 -C 4) -alkyl, N- (C 1 -C 4) -alkyl, (C 1 -C 4) -alkyl-pyrrolidinyl- (C 1 -C 4) -alkyl ) -alkyl, aryl- (C 1-) -hydroxyalkyl, aryloxy- (C 1-) -hydroxyalkyl, aryl-carbonyloxy- () -alkyl, aryl-carbonyl- (C 1-4) -alkyl, aryl- (C 1-4) -alkyl, diaryl- (C 1-4 ) alkyl, aryl-carboxamido- (C 1-4) -alkyl, aryl- (C 1-4) -alkenyl, benzimidazolyl- (C 1-4) -alkyl or aryloxy- (C 1-4) -alkyl, wherein aryl means phenyl or phenyl monosubstituted by halogen, (C-) -alkyl or (C) -alkoxy, and R 9 and R 6 independently of one another denote hydrogen or (C 1-4) -alkyl or together with the nitrogen atom morpholino and X is oxygen one or sulfur,. the optical and geometric isomers of these compounds and their pharmaceutically acceptable acid addition salts. The compounds of the above formula A, their optical and geometric isolates and their pharmaceutically acceptable acid addition salts can be prepared according to the invention by In particular, the compounds of the above formula A, their optical and geometric isomers and their pharmaceutically acceptable acid addition salts, as well as various intermediate steps can be prepared as illustrated in detail in the following. the compounds of formula A, wherein X is 0 by the formula. wherein R 1, R 2, R 6 R 6 are as previously described and may be prepared as set forth and further described in Schemes I to IV. wherein R, R 7 R "are as previously described. by reacting the primary amine of formula XIV with chloroformic acid ethyl ester to the urethane of formula III, which is reduced with lithium aluminum hydride to the N-methylamine of formula IV. According to a broad aspect, the compounds of formula IV can be prepared by reductive alkylation of the compounds of formula XIV using the corresponding aldehyde, e.g. acetaldehyde and the like, and sodium cyanoborohydride under known conditions (see, e.g., R.F. Borch, J. Am. Chem. Soc, 93, 2897 (1971). The Birch reduction of the amine of formula IV with lithium in t butanol-containing ammonia gives the dihydroamine of formula V. Other variants of the Birch reduction can also be used, thus the amine of formula IV can be reacted with an alkali metal such as sodium, lithium, potassium or cesium in ammonia or an amine such as methylamine or ethylamine in The reaction generally takes place at the boiling point of the solvent or lower, for example from -78 DEG to 15 DEG C. If ammonia is used, the reaction proceeds at reflux. The hydrolysis of the dihydroamine of formula V proceeds readily according to conventional methods for hydrolysis of enol ethers, for example with aqueous acid. perchloric acid. They can be used in aqueous solutions or mixed solvents. At least two equivalents of water per moles of dihydroamine and more than 1 equivalent of acid are required. Tetrahydrofuran, benzene, diethyl ether, acetone, toluene, dioxane or acetonitrile are examples of useful solvents. For example, the hydrolysis of the dihydroamine of formula V, wherein R "is methyl in 2 n hydrochloric acid at room temperature or higher in aqueous acetic acid between 40 ° C and reflux to the diketone of formula VI, wherein R" is methyl. The diketone of formula VI is condensed in a Knorr condensation to the dihydroindolone ethylamine of formula IX. The Knorr condensation is a well-known process for the preparation of pyrroles, and the process can be used in all known variants (see, for example, conditions cf. J. M. Patterson, Synthesis, 281, 1976 and the literature citations cited therein). Thus, it is assumed that e.g. the reaction of an isonitrosoketone of formula VII in the presence of a reducing agent, e.g. with zinc in aqueous acetic acid or hydrochloric acid, proceeds over the aminocarbonyl compound of formula VIII, which is then condensed with the diketone of formula VI to dihydroindolone-ethylamine of formula IX. Alternatively, the condensation may take place with an aminocarbonyl compound of formula IX or a preference, such as an aminoketone hydrochloride or an acetal derivative of an aminoketone or aminoaldehyde. The application of. an advantage of the aminoketone or aminoaldehyde is preferred, as such compounds readily tend to self-condense. They can preferably be used in situ, during which the aminocarbonyl components are released in the presence of the diketone of formula VI. The aminocarbonyl component reacts immediately to the dihydroindolone ethylamine of formula IX. The diketone of formula VI does not necessarily have to be isolated for the implementation of the Knorr condensation, as the reaction conditions used are sufficient for hydrolysis of the dihydroamine of formula V to the diketone of formula VI. The Knorr condensation is preferably carried out at a pH of approx. 2 to 6. At a pH significantly higher than 6, significant loss of yield occurs due to Formation of self-condensation products of the aminocarbonyl compound of formula VIII. Preferably an isonitrosoketone of formula VII and zinc dust in aqueous acetic acid are condensed with a diketone of formula VI, wherein R "is methyl, to give the product, the dihydroindolone-ethylamine of formula IX, wherein R "is methyl. The Knorr condensation preferably proceeds at a temperature of from about room temperature to reflux. The isonitrosoketones of formula VII are known compounds (see, for example, Ferris, J. Org. Chem., 24, 1726 (1959) or can be readily prepared by nitrosation of corresponding ketones, for example with an alkyl nitrite or in the case of strongly Examples of isonitrosoketones which may be used in the Knorr condensation are as follows: Examples of aminocarbonyl advantages which may be used in the Knorr condensation are as follows: The amine of formula IX is transferred into The compound of formula Ia through an intramolecular Mannich reaction The Mannich reaction is normally carried out from a ketone and a dialkylamine salt, for example dimethylamine hydrochloride and formaldehyde (eg as aqueous solution, as paraformaldehyde or as trioxane) in In the embodiment described herein, an acid addition salt "of the dihydroindolone ethylamine of formula IX is reacted with formaldehyde, added in the form of paraformaldehyde, trioxane or sol. m aqueous formaldehyde in a solvent. For example, a high-boiling hydroxylic solvent such as amyl alcohol, octanol, ethylene glycol or diethylene glycol monoethyl ether, a high-boiling polar aprotic solvent such as dimethylformamide, N-methyl-pyrrolidinone or diethylene glycol dimethyl ether, a low-boiling sub-polanol pressure, or a low boiling aprotic solvent under pressure, such as dioxane or tetrahydrofuran, at a temperature in the range of about 135 ° C to 200 ° C to prepare pyrrolo [2,3-g] isoquinolines of formula Ia. The reaction leads especially at temperatures below 150 ° C to a mixture of cis- and trans-isomers, i.e. e.g. when R "is methyl, to compounds of the formulas. Prolonged heating of the reaction mixture or separate heating of the isomeric mixture of the hydrochlorides of formulas I'a and I" a, e.g. in ethylene glycol 2 hours under reflux can be used to equilibrate the cis and trans isomers to a final ratio, predominantly containing trans isomers which can be easily isolated by crystallization or by chromatographic separation. in which R According to Formula Scheme II, compounds of formula Ic 'are prepared by alkylation or acylation of the pyrrole nitrogenate moiety in a compound of formula Ia' and other N-6-alkyl derivatives to form the pyrrole anion with strong base, for example sodium amide, potassium hydride, sodium methylsulfinylcarbanion or butyllithium, or with an alkali metal and subsequent reaction with an alkyl or acyl halide in a solvent such as tetrahydrofur an, dioxane, ethyl ether, dimethylformamide or dimethylsulfoxide. For example, the treatment gives a compound of formula Ia ', wherein Rer is methyl and Retyl, with sodium in liquid ammonia and subsequent reaction with the methyl iodide 1-methyl derivative, i.e. a compound of formula IC wherein R 1 is methyl and R 3 is ethyl and R is methyl. Similarly, the reaction of a compound of formula Ia, wherein R 1 is methyl and R 3 is ethyl, with butyllithium in tetrahydrofuran at -30 ° C and subsequent reaction with the benzoyl chloride gives the 1-benzoyl derivative, i.e. a compound of formula Ic, wherein R 1 is benzoyl, Rmethyl and Retyl. )) or by acid or base hydrolysis of a urethane derivative as indicated by K. C. Rice (J. Org. Chem. 40, 1850 (1975)). the secondary amine of formula Ib For example, a compound of formula Ia ', wherein Rer is methyl and Retyl, is refluxed in diethyl ketone with excess chloroformic acid ethyl ester and potassium bicarbonate for 3 hours to give a compound of formula XIII, wherein Rer is methyl and Retyl. Hydrolysis of the aforementioned compound with concentrated hydrochloric acid in acetic acid under reflux for 24 hours gives a compound of formula Ib, wherein R south in refluxing ethanol.worl V R2 'R3 ° 3 R R <, is as £ orut described ,. According to Formula Scheme III, the compounds of formulas Ic, Id and Ie are prepared from the secondary amine of formula Ib, the starting material for the preparation of numerous derivatives encompassed by formula I, by substitution on the basic amine nitrogen (N-6) and / or on the pyrrole nitrogen (N-1). For example, the treatment of a compound of formula Ib with an alkyl halide such as ethyl bromide, an alkenyl halide such as allyl bromide, a cycloalkylalkyl halide such as chloromethylcyclopropane, or an aralkyl halide such as benzyl bromide, in the presence of a base, e.g. potassium carbonate, in acetone, 2-propanone or dimethylformamide, the corresponding substituted compound of formula Id, i.e. wherein R 1 'is alkyl, alkenyl, cycloalkylalkyl and aralkyl. With reactive halides the reaction can proceed at room temperature, but with less reactive halides reflux temperatures are used, and in many cases the reaction rate can be increased by adding an iodide, such as lithium iodide, to the reaction mixture. The reaction of a compound of formula Ib with epoxyalkanes connection with formula Id. The treatment with a substituted epoxyalkane gives the 2-substituted 2-hydroxyalkyl analogs of a compound of formula Idf.eks. the reaction of a compound of formula Ib with styrene oxide gives a compound of formula Id, wherein R 'is 2-phenyl-2-hydroxyethyl. The reaction normally takes place in the presence of an alcoholic solvent, such as methanol, around room temperature up to the reflux temperature of the reaction mixture. The epoxyalkanes are either commercially available or are prepared by epoxidation of corresponding olefins or by methylation of a ketone with a sulfonium methylide or sulfoxonium methylide, e.g. dimethylsulfonium methylide. thus, e.g. The compound of formula Ib can be converted into the compound of formula Ie according to a process in which the basic amine nitrogen (N-6) in formula Ib is protected with a hydrolyzable or hydrogenolysable protecting group, the pyrrole nitrogen (N-1) and the protecting group are cleaved. Typical protecting groups are acetyl, t-butoxycarbonyl, benzenesulfonyl or benzyl. The reaction of the protected intermediate takes place practically as described for the transfer of the compound of formula Ia into the compound of formula Ic '. The substituted intermediates are liberated by base or acid hydrolysis or hydrogenolysis, depending on the protecting group, for the protecting group. For example. the compound of formula Ib is treated, wherein R 1 is methyl and R -. ethyl, with formic acid / acetic anhydride to give the 6-formyl derivative. The treatment of the derivative with sodium hydride in dimethyl sulfoxide and subsequent treatment with methyl iodide and acid hydrolysis gives the compound of formula Ie, wherein R 1 is methyl, R methyl and Retyl. . The treatment of a compound of formula Ib with a haloalkylamine in the presence of a base, e.g. potassium carbonate, or an aziridine gives amine-substituted analogs of a compound of formula Id. The reaction conditions are as described for the preparation of the alkyl derivatives. In many cases where R 'in the compound of formula Id does not contain functional groups which can be subjected to an alkylation or acylation, the methods given in formula scheme III can be used directly for the preparation of N-1 -substituted analogues of formula Ic. Alkyl rings can occur in compounds wherein R represents hydroxyalkyl, phenylhydroxyalkyl, halophenyl-hydroxyalkyl, alkylphenyl-hydroxyalkyl, alkoxyphenyl-hydroxyalkyl, aryloxy-hydroxyalkyl, alkoxy-hydroxyalkyl, cycloalkyl-hydroxyalkyl or 6N-R-hydroxyalkyl. of each other are hydrogen or alkyl or together with the nitrogen atom form a 5- or 6-membered heterocyclic ring. The functional groups therein, e.g. hydroxyl or sec-amino, must be protected with a base-stable protecting group, such as tetrahydropyranyl. After the N-1-alkylation, the protecting group is cleaved by acid hydrolysis. The nuclei I, II and III can form both the trans-isomers of formula. wherein R 1 and R 2 as previously described, and cis isomers of formula wherein R The pure trans isomer can be separated by chromatography or crystallization. In addition, the mixture can be isomerized, as described for the isomerization of trans and cis isomers of the oxo compound of formula I'a 'and I "a'. Wherein R Formula Ia is described in Formula Scheme IV, in which the isoquinoline ring is formed to form the pyrrole ring. According to Formula Scheme IV, the (3,5-dimethoxyphenyl) ethylamine of Formula IV is refluxed with aqueous formaldehyde to give the tetrahydroisoquinoline of Formula X. The Birch reduction of the tetrahydroisoquinoline of Formula X with lithium in t-butanol-containing liquid ammonia under substantially the same conditions described for the Birch reduction of the compound of formula IV give the hexahydroisoquinoline of formula XI. Hydrolysis of the crude hexahydroisoquinoline of formula XI under practically the same conditions as described for the hydrolysis of the dihydroamine of formula V gives the diketone of formula XII. The compound of formula XII is reacted in a Knorr condensation, as described in the preparation of the dihydroindolone ethylamine of formula IX, with the isonitrosoketone of formula VII or with the aminocarbonyl compound of formula VIII to the pyrroloisoquinoline of formula Ia. Preferred is the reaction sequence of Formula IV from the amine of formula IV, wherein R "is methyl, leading to the corresponding N-methyl-pyrroloisoquinoline of formula Iasom mixture of trans-isomeric Ia 'and cis-isomers of formula I" a '. To obtain essentially the trans isomer of formula I'a ', the same methods for the isomerization of the mixture of the pyrroloisoquinoline of formulas Ia' and I "a ', as previously described, can be used. The compounds of formula A, wherein X is S, The compounds of formula II are generally prepared by reacting phosphorus pentasulfide with keto compounds of formula I. When the compound of formula I does not have functional groups such as can react with phosphorus pentasulfide, in addition to the 4-oxo group, the compound of formula I can be directly transferred to the compound of formula II by heating with phosphorus pentasulfide in an inert organic solvent. phosphorus pentasulfide, for example, when R xyalyl, aralkenyl, aryloxyalkyl or trifluoroalkyl having 2 to 6 carbon atoms, or when R or R is acyl, these groups must be protected from reaction and then liberated again from the protecting group. Keto groups can e.g. protected as ketal such as ethylene ketal and alcohol groups as ether derivatives such as benzyl ether. On the other hand, ions of formula II can be prepared according to suitable methods described in formula schemes V and VI, wherein R ', R, Rog R "are as previously described. Preferred solvents are tetrahydrofuran, benzene and dioxane, and the reaction generally takes place at reflux temperature The compound of formula IIa may be alkylated or acylated to the compound of formula Ile in the same manner as in formula II for the conversion. The further compounds of formula II can be prepared as described in formula scheme VIi, wherein R, R, and Rog R 'are as previously described. to the ion of formula IIb Then there are conversions of the compound of formula IIb to the compounds of formulas Ile, Ild and Ile similar to Formula Scheme III for the analogous oxo compound Ib by the transfer in the compounds of formulas Ic, Id and Ie. In these reactions, both the trans isomers of formula wherein R, R, Rog Rer as previously described, and the cis isomers of formula. wherein R 1, R 2, R 3 and R 5, as previously described, are formed by the compounds of formula II, the trans isomer predominating. The pure trans isomer can be isolated by chromatography or crystallization. In addition, the mixture can be isomerized as described for the isomerization of trans and cis isomers of the oxo compound of formula Ia1 and. The compounds of formula A form acid addition salts with inorganic or organic acids. Thus, the pharmaceutically acceptable acid addition salts form with both pharmaceutically acceptable organic and inorganic acids, e.g. with hydrohalic acids, such as hydrochloric acid, hydrobromic acid, hydroiodic acid, other mineral acid salts, such as with sulfuric acid, nitric acid, phosphoric acid or the like, with alkyl and monoarylsulfonic acids, such as ethanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid and the like, other organic acids, tartaric acid, acetic acid, acetic acid citric acid, benzoic acid, salicylic acid, ascorbic acid, etc. pharmaceutically acceptable acid addition salt and subsequent reaction of the free base thus obtained with a reagent to give a pharmaceutically acceptable acid addition salt. The acid addition salts may also form hydrates. The compounds of formula A and their pharmaceutically acceptable acid addition salts have neuroleptic activity. Surprisingly, however, they lack hypotensive activity, and they show only weak cataleptic activity. Accordingly, the compounds of formula A are useful as antipsychotic agents, e.g. in the treatment of Schizophrenia. The activity of the compounds of formula A, which make them useful as antipsychotic agents, can be demonstrated by known methods in warm-blooded animals. trained rats in experimental chambers equipped with a reaction arm, a steel wire base for dispensing an electric shock and a speaker for acoustic stimulation. Each attempt consists of a warning tone of 15 sec. (conditional stimulus), which continues for another 15 sec. and below is followed by an electric shock (unconditional Stimulus, 1.0 mA, 350 V AC). The rats can terminate an experiment at any location by depressing the reaction arm. A reaction in the first 15 sec. warning tone ends the attempt for a shock is handed out, and is considered an obstacle reaction, while a reaction that occurs during the shock delivery is an escape reaction. The experiments are performed every 2 min. for a trial period of 1 hour (30 trials per period!) Ovate rats show a reliable baseline for the obstruction reaction (0 to 3 absent obstruction reactions per period). During a control period, during the control periods the rats receive only vehicle.Each week changes a control and a test period, i.e. each animal serves as its own control.Each test period is divided into 3 consecutive 20 min sections (10 trials). reactions are summed over all individuals at a given dose during each section. This number is expressed as a percentage of the number of trials performed within this range. gnes as 50% obstacle block (VB 50) is obtained from the dose / effect comparison line set up according to the least squares method. The minimum dose that elicits a 20% blockade of the escape reaction (FB 20) is read from a dose / effect diagram. To achieve these values, the effect is recorded in% against log of dosage. Antipsychotic agents can be distinguished from other types of active substances that affect the behavior of rats in this way of working through the greater difference between dosages, which block the prevention reaction, and doses that block the escape reaction. Efficacy of antipsychotic agents with known therapeutic applications and properties is significantly and strongly related to their efficacy by this method. Accordingly, the compounds of formula A may be used therapeutically in dosages which are consistent with their efficacy by the test method. , 8a-trans-1H-pyrrolo- [2,3-g] isoquinolin-4-one hydrochloride which showed an LD of e.g. 350 mg / kg p.o. in mice used as a test substance, neuroleptic activity is observed at a VB 50 of 0.7 mg / kg p.o. and 0.095 mg / kg s.c., at (-) - enantiomers of the aforementioned compound neuroleptic activity at a VB 50 of 0.48 mg / kg p.o. kg p.o. when using 2,3,6-trimethyl-4,4a, 5,6,7,8,8a, 9-octahydro-4a, 8a-trans-1H-pyrrolo- [2,3-g] isoquinoline 4-one hydrochloride as test substance. When using N- [2- (3-ethyl-4,4a, 5,6,7,8,8a, 9-octahydro-2-methyl-4-oxo-4a, 8a- trans-1H-pyrrolo [2,3-g] isoquinolin-6-yl) ethyl] -4-fluorobenzamide as a test substance, a neuroleptic activity is observed at a VB of 3.5 mg / kg p.o. When 3-ethyl-2-methyl- 6- [4- (4-fluorophenyl) -4-oxobutyl] -4,4a, 5,6,7,8,8a, 9-octahydro-4a, 8a-trans-1H-pyrrolo [2,3-g] -isoquinolin-4-one is used as a test substance, neuroleptic activity is observed at a VB of 0.19 mg / kg p.o. Similarly, when 3-ethyl-2,6-dimethyl-4, 4a, 5,6, 7, 8, 8a .9-octahydro-4α, 8α-trans-1H-pyrrolo [2,3-g] in socinolin-4-thione are used as test substance neuroleptic activity at a VB of 0.94 mg / kg p.o. The compounds of formula A and their pharmaceutical tolerable acid addition salts have antipsychotic effects which are qualitatively similar to those of haloperidol, trifluorperazine and molindone known from r its therapeutic use and properties. Thus, the compounds of formula A show an activity sample which combines the action of known antipsychotic agents and safety. The compounds of formula A and their pharmaceutically acceptable acid addition salts can be used in the form of customary pharmaceutical formulations. For example, suitable oral dosage units contain or range from 0.05 to 50 mg, and suitable oral dosages in warm-blooded animals range from about 0.001 mg / kg pr. day and approx. 10 mg / kg pr. day. For each particular warm-blooded animal, however, the specific dosage may vary, and it should be adjusted depending upon the individual requirements and the professional judgment of the administration of a compound of formula A or a pharmaceutically acceptable acid addition salt thereof to the subject or subject. Furthermore, the frequency with which such a dosage form is administered will vary depending upon the amount of active drug present and the needs of the pharmacological situation. for oral or parenteral administration. Such dosage forms include tablets, suspensions, solutions, and the like. Furthermore, the compounds of formula A may be incorporated in the form of suitable hard or soft capsules and given as such. The nature of the inert excipients used to formulate the compounds of formula A and their pharmaceutically acceptable acid addition salts into oral and parenteral dosage forms will be apparent to one skilled in the art. These excipients, whether organic or inorganic, are e.g. water, gelatin, lactose, starch, magnesium stearate, talc, vegetable oils, resins, polyalkylene glycols, etc .. Furthermore, if desired, preservatives, stabilizers, wetting agents, emulsifiers, salts for changing the osmotic pressure, buffers and the like. incorporated into such recipes. Since the compounds of formula A and their pharmaceutically acceptable acid addition salts have an asymmetric carbon atom, they are normally present as racemates. The cleavage of such racemates into the optically active isomers can be by known methods. Many racemates can be precipitated as eutectics and then separated. However, the chemical cleavage is preferred. Thereafter, diastereomers are formed from the racemic mixture with an optically active cleavage agent, e.g. optically active acid, such as (+) - tartaric acid, to form a diastereomeric salt. The diastereomers formed are separated by fractional crystallization and can be transferred to the corresponding optical isomeric base. Thus, the invention encompasses both the optically active isomers of the compounds of formula A and their racemates. the possible different spatial arrangements of the atoms understandably that the compounds according to the invention can be obtained in more than one possible geometric isomeric form. The compounds of formula A described and required shall include all such isomeric forms. Thus, the examples given herein are to be understood as illustrative as particular mixtures of geometric isomers or individual geometric isomers and not as limiting the scope of the invention. The following examples further illustrate the invention. All temperatures are given in ° C unless otherwise stated.Example 1 (intermediate). Preparation of N-2- (3,5-dimethoxyphenyl) -ethylcarbamic acid ethyl ester. 600 ml of water, 600 ml of methylene chloride and 150 ml of 1 N sodium hydroxide solution

Description

Movable furniture base.

The present invention relates to a mobile chair structure, and in particular a mobile chair of the type that is suitable for use by dentists in their dental office, by hairdressers and beauticians at their normal workplace, and by any other profession, particularly in conditions where a patient or customer normally is sitting in the chair and it is desired to move the chair with the patient or customer in it from one place to another in the room where the chair is normally placed, or from one room to another.

For many years, for example, dentists' and hairdressers' chairs in particular have

been used in a stationary location on the floor of the dentist's office or in the hairdressing salon. These chairs were usually arranged so that the seat part as well as the back attached to it could be moved

pivotable in relation to the undercarriage about a mainly vertical axis. In many cases, the back and footrest are adjustably movable in relation to the chair seat so that the patient or customer can be placed in different angles of the sitting position, and can also be placed mainly horizontally.

It has also been common to use chairs of this type where different means are arranged to lift the seat to different vertical positions in relation to the stationary undercarriage. Most such means are operated by hydraulic cylinder units which require either a hand pump or a power driven pump to move the piston in the unit and thereby lift the seat relative to the chassis.

In hairdressing salons and beauty salons, especially when shampooing, it is currently essential to have the customer sitting in the chair while the hair is treated with shampoo, and the customer must then leave the chair and go to a sink where he is usually placed on a low chair during rinsing of the hair. Often two or three such operations are required, including repeated applications with shampoo and repeated rinsing, all of which are of a troublesome nature mainly due to that the chair is motionless in the horizontal direction.

The trend in modern dental offices is strongly towards using cabinet units arranged along specific walls in the office, including cabinets and units that can be inserted into or attached to cabinets, or supported by plinths. Such cabinets and units contain the various hand instruments commonly used in dentistry, such as syringes, pulp testers, etchants, liquid-powered dental hand tools, etc., and such cabinets are sometimes arranged for limited movement of a collection of such instruments relative to the cabinet.

While the tendency in the furnishing of dental offices is currently in the direction of relatively fixed counters and cabinets along the walls in relatively cramped spaces, the tendency in instruments;

such as x-ray machines, lights and other instruments of this type,

still decided in the direction of using swing arms and hinged joints which, especially in contrast to the otherwise neat appearance of the cabinet fittings in the room, seem somewhat clumsy and out of style. In principle, it is therefore still necessary, in accordance with current practice, to bring the instruments to the patient, and there is no tendency to move the patient in relation to the instruments, except such movement as is carried out only by turning the chair about the vertical axis in the undercarriage.

The main purpose of the present invention is to provide a chair for use by medical and dental patients, customers in hairdressing salons or beauty salons etc., and in particular, for chairs of this type to provide a base which is movable in relation to the supporting surface such as the floor, horizontally , linear, while at the same time the chair is allowed to move about a mainly vertical axis either while the chassis is stationary or moving.

One of the main advantages of arranging such movement of the chair as mentioned above is that it provides flexibility in terms of to achieve the most desirable and efficient operating position both for the operator and for the person sitting in the chair, for each given operation. Operation in the most efficient and/or comfortable position provides simplicity in treatment, which is a goal in modern dentistry, as well as in hairdressing and beauty salon treatment, resulting in minimal use of time and maximum savings.

Although some equipment is currently supported by plinths fitted with casters to make them mobile so that they can be moved to the patient or client in dental offices or in hairdressing and beauty salons, there are a number of prominent advantages to moving a chair , with the patient or customer seated in it, to certain devices, instruments or areas in a treatment room. The most prominent advantages are: (1) Improved aesthetics due to absence of pulleys, pivots and tension arms and the presence of only a minimum of cables, rudders and similar service arrangements as these do not need to be connected to a movable chair to nearly the extent as in relation to a stationary chair. The appearance is further improved by the fact that cabinets, units, counters etc. can be stationary in the position best suited for them in the room, whereby service arrangements for such units can be hidden behind them or in the walls. (2) Maximum efficiency is achieved by moving the patient or customer to the instruments or devices instead of the other way around, as a movable chair involves less overall movement, as well as providing the greatest possible combination of desired mutual position between the dentist or practitioner and the patient or customer, as well as any assistants who may participate in such treatments. (3) Best possible accessibility to wall cabinets or counter cabinets, because by removing a unit from a position along a wall or from a counter to a chair, you often block other units or cabinet areas from access. (4) Better traffic flow is achieved in the room, especially for a dentist or practitioner as well as for assistants, because there is maximum available floor space when all or a maximum number of devices and instruments remain mainly in their normal positions along the wall or the like. (5) Possibility of reduction of certain units and instruments due to that there will be no significant need to move any of them from their stationary position to the chair, as the chair is pushed away to the device or instrument according to the invention. (6) It is possible to obtain a more orderly and compartmentalized arrangement of a dental office and a hairdressing or beauty salon, because all units and instruments necessary for certain operations are placed close to each other to save space and movement for dentists, operators and assistants . In a dental office, for example, all crown and bridge cabinets, devices and instruments can be mounted along one wall, all prosthetic devices and equipment along another wall, all operative instruments and equipment along a third wall, and X-ray and various equipment along a fourth wall.

The purpose of the invention is, in a known manner, to use compressed air to create an air membrane between the chassis and the supporting surface, such as a floor, whereby the chair chassis as well as any chair associated with it can be moved by the application of limited human power applied in a horizontal direction towards the seat of the chair or back to effect a desired rotation or linear movement of the chair and chassis relative to a floor surface.

A further object of the invention is to provide power-driven means in the undercarriage which can quickly and for reasonable periods of time produce a sufficient supply of compressed air to provide the air film on which the undercarriage slides over a floor surface while it is moved as desired, the undercarriage also are means of power for the seat's loft mechanism.

The invention thus relates to a displaceable furniture base, preferably for chairs, provided with means which, when activated, allow the base to float during horizontal movement on a film of air between the base and the floor, and the invention is characterized by the fact that said means comprise, as the last link, a replaceable ring-shaped membrane unit placed in the bottom part of the undercarriage at its circumference and arranged in such a way that, when air is supplied under pressure, it is converted into an air-releasing floating cushion for the undercarriage.

According to a further feature of the invention, the membrane unit is adapted to a correspondingly designed air-conducting ring-shaped distribution chamber in the circumference of the chassis so that the membrane unit forms the bottom part of the ring-shaped chamber.

These and further features of the invention will be apparent from the description, which, supported by drawings, goes through an exemplary embodiment.

In the drawings are:

Fig. 1 a side view of a frame for a chair which is shown fully extended and an example of a chair seat and back supported by the frame shown dotted, Fig. 2 is a vertical section through it in fig. 1 showed the undercarriage on a larger scale than in fig. 1, and showing various details of the mechanism mounted in the undercarriage, Fig. 3 is a vertical side view of that in fig. 1 and 2 showed chair frames, but as the section is taken at right angles to the section in fig. 2 and on a slightly smaller scale than in fig. 2, Fig. 4 it is in fig. 1 to 3 show the chassis seen from above and to the same scale as used in fig. 3, Fig. 5 is a partial vertical view of a part of the mechanism for lofting the chair's support means which is movably carried by that in fig. 1 to 4 shown chassis, Fig. 6 a part of the one in fig. 5 shown carrying mechanism seen from above and partially cut away to show details, Fig. 7 a vertical section showing part of the construction of the circumference of the chair base which is otherwise shown in section on a smaller scale in fig. 2 and 3, as the arrangement in fig, 7 for example shows the air drain and sealing means attached to the bottom of the chair frame in an inflated state, Fig. 8 is a partial vertical section of part of the threaded means that can be operated to raise and lower the support means of the chair in relation to the underframe, Fig. 9 is a partial vertical section showing a modified part of the perimeter of the underframe and also the construction of the lining means connected to the underframe, Fig. 10 a partial view from above of the mechanism for lofting the support means of the chair, Fig. 11 a partial vertical section of the circumference of the undercarriage, similar to fig. 7, but as the cut is circumferentially distanced from that in fig. 7 showed sections for the purpose of showing further details. Fig. 12 an exemplary electrical connection diagram for the motors in the chair base and control means for these.

With reference to the drawings, and in particular fig. 1 to 3, the undercarriage 10 according to the invention is preferably in the form of a metal stop which is somewhat close to bell-shaped in order to provide ample space for the power-driven mechanisms of various types mounted therein, and also to provide an outward facing flange 12 along the circumference. The bottom surface of the undercarriage, or at least certain circum-

prevails of this, can lie against a relatively flat and horizontal

load-bearing surface, such as a floor 14.

Carried by, and vertically movable in opposite directions in relation

to, the upper part of the chassis 10, a top piece 16 comprising chair seat supports is mounted to which, for example, a combined chair seat and back 18 is connected. It must be understood that the combination of chair seat and back 18 thus shown, for example, in fig. 1 is only given for illustrative purposes and does not form any part of the invention. It must also be understood that the undercarriage 10 can be used to carry a plurality of different types of chair seats and/or backs attached to it, comprising e.g. dentist's chair seats, hairdresser's chair seats, chair seats for beauty care, operating tables, etc.

The undercarriage must primarily, with the help of gravity,

rest on a load-bearing surface such as a floor 14, without on

some way to anchor to this. The area of the underframe's base surface is so ample that it allows great movement of the combined chair seat and back 18 in various pivoted positions in relation to the underframe 10, particularly positions based on a horizontal pivot, without the risk of tilting or overturning the underframe 10

in relation to the bearing surface 14. Upper surface of the circumferential flange 12

preferably projects radially outwards at a relatively flat angle with the floor surface in the vicinity of which it is designed so that it forms

the least possible obstacle in the event that the handlers either accidentally or intentionally bump against the flange with their feet.

Inside the underframe 10, there is arranged a mechanism which does not form any part of the invention for lofting and lowering the top piece 16 to which a chair seat can be connected. In order to stabilize the vertical movement of the top piece 16, especially when the weight connected to this is not evenly distributed between opposite sides of the vertical shaft on which the top piece can be moved, suitable lining means are provided. In the preferred construction, these means comprise a pair of guide rods 20 which are connected at their upper ends to the top piece 16, as clearly shown in fig. 3, the rods being fast through vertical guide bearings 22 which are preferably formed in the upper part of the stop of which the undercarriage 10 consists. Under most normal working conditions, the guide rods 20 move at a relatively low speed in relation to the bearings 22, which is why the guide bearings can be of a relatively simple journal bearing type, of which different types can be obtained, including those impregnated with permanent lubrication. Bearings coated with self-lubricating resins are suitable for reducing friction and sticking. It will also be seen that the control rods 20 are preferably evenly spaced on opposite sides of the vertical axis in the top piece 16 and the chassis 10, as can be seen from fig. 3.

In the center of the top piece 16, a screw shaft 24 is attached with its upper end which, in the preferred construction shown here, is stationary in relation to the top piece. A ball nut 26 is connected to the screw shaft 24 which is attached to the upper end of a sleeve 28 which is rotatably supported by a reduction gear 30 of a suitable commercial type.

Across the lower part of the chassis 10 there is a partition wall 32 which is preferably stiffened by radial ribs 33 and in the center is provided with an opening 34 through which the lower end of the gear 30 is accessible after removing a bottom cover plate 36, the cover plate being held closed position of suitable screws 38. The drive means for the gear 30 comprise an electric motor 40 which is carried by the mechanism described below so that it can be regulated in relation to the gear 30.

A carrier plate 42 which is provided with a seat 44 on its lower surface receives in this seat the upper end of the gear 30, and the plate 42 is otherwise attached to the gear 30 by suitable means such as set screws 46 etc.

A lower post 48 is attached to the plate 42, for example by welding, to which an upper post 50 is connected in such a way that it can be set vertically in relation to the lower post by means of suitable means such as a slot 5 2 and clamping bolts 54. A horizontal support angle 56 provided with an anti-friction bearing 57 is attached to the upper end of the upper post 50.

In the inner bore in the anti-friction bearing 57, the upper end is occupied by a drive shaft 58 which is attached to the bearing so that it rotates with it. The upper portion of the shaft 58 is also surrounded by a journal bearing boss 60 of bronze to permit rotation of an upper clutch link 62 relative to the shaft 58 under certain conditions to be described below. The clutch link 62 is also provided with a suitable seat to receive an input pulley 64 which is preferably locked to the upper sleeve part of the clutch link 62, as clearly shown in Fig.5.

A pair of arms 66 are connected to opposite sides of the upper post 50 and midway between its ends, which with their outer ends rake into suitable grooves 68 taken out in the circumference of a non-rotating friction clutch plate 70 which also serves as a brake. Between the ends of the arms 66 and the tracks 68, preferably elastic bosses are inserted to prevent the brake shock from affecting the plate 70 unfavorably. A bronze clamping disc 72 is also mounted on the clutch link 62 for direct pressure against an annular pressure plate 74, as there is a bottom clutch hub 76 through the center opening in the annular plate 74. The hub 76 is annular to accommodate the shaft 58, and in opposite parts of the lower surface, the hub 76 is provided with cam grooves 78.

Attached to the shaft 58 directly below the hub 76 is a lower clutch plate 80 provided with an upper hub 82 which is also ring-shaped and is complementary to the hub 76. In diametrically opposite parts of the hub 82's surface there is arranged a V-shaped chamber 84 which in the form are complementary to the cam grooves 78. The pressure plate 74 and lower clutch plate 80 are respectively mounted close to the upper and lower surfaces of the clutch plate 70 which is attached non-rotatably to the upper post 50.

The plate 80 is forced upwards by a compression spring 86 which surrounds a threaded part 88 of the shaft 58 on which a threaded compression sleeve 90 is mounted, whereby turning the sleeve 90 in opposite directions respectively compresses and releases the tension in the spring 86 so that a corresponding adjustment of the pressure with which the plates 74 and 80 rest against opposite sides of the relatively fixed friction plate 70.

The shaft 58 is provided at its lower end with an enlarged hub 92 which has an axial bore upwards to receive the upper end of the power input shaft 94 which is fast upwards from the gear 30, the shaft 94 serving to drive the gears in the gear 30 for the purpose of turn the sleeve 28 which drives the ball nut 26.

As will particularly be seen from fig. 10, the support plate 42 is provided with an angle arm 96 which extends radially from the plate and is solidly attached to it. An angle 98 is rotatably mounted to the outer end of the arm 96 which can rotate about the axis of the pivot bolt 100. A U-shaped cradle 102 of conventional construction is fixedly connected to the angle 98, the opposite arms of the cradle being provided with arc-shaped seats 104 which receive the usual mounting collars on the engine 40. Conventional clamping straps 106 extend around said seats in the engine 40 and grip with the opposite arms on the angle 102 so that the motor 40 is carried in such a way that its axis is parallel to both the pivot bolt 100 and the input shaft 94. The usual mounting means at opposite ends of the motor preferably comprise rubber which is arranged at the opposite legs of the cradle 102.

The upper end of the motor 40 drive shaft 108 is provided with a pulley 110, and around this and the input pulley 64 is a belt 112, the pulley 64 being connected to the input shaft 94. To set the belt in the desired tension, it can be seen from fig. 10 that the angle arm 96 is provided with a vertical extension 114 through which a set screw 116 is threaded and provided with a lock nut. The protruding end of the set screw 116 rests against an upright part of the angle 98 to which the cradle 102 is attached. As the screw 116 is adjusted in opposite directions, the tensioning of belts will consequently. 112 vary accordingly.

Attention is now particularly drawn to fig. 5 relating to the operation and operation of the clutch and brake device comprising the plates 74 and 80, as well as the friction clutch plate 70. As will now be explained, axial movement between the plates 74 and 80 is permitted, but mutual rotation between the plates is prevented by the use of several short bolts 118 which at their upper ends are attached to the plate 74, while the lower part of the bolts 118 are fast into complementary holes 120 which are taken out in the lower clutch plate 80. In the rest position, the spring 86 normally presses the plate 80 upwards against the non-rotatable friction clutch or brake plate 70 which is again forced against the pressure plate 74 which is arranged in vertical contact with the stop disc 72 which is carried by the upper clutch link 62.

When the reversible electric motor 40 is energized, it drives the input pulley 64 which rotates the clutch link 62 and the hub 76 which is provided with cam grooves 78. The direction of rotation of the motor 40 will determine which of the angularly arranged surfaces of the cam grooves 78 will engage with the corresponding surfaces of the cams 84. However the direction of rotation of the clutch joint 62 will, however, cause camming between the grooves 78 and the cams 84, whereby there will be a limited axial movement of the clutch plate 80 away from the friction clutch plate 70. A limited self-adjustment of the same in relation to the plates 74 and 80 is also permitted, especially due to the elastic lining means in the grooves 68 which receive the arms 66 which prevent rotation of the plate 70.

When, as a result of the cam action described above, the friction clutch or brake plate 70 is released by the lower clutch plate 80, the shaft 58 and the input shaft 94 to which it is fixedly connected by means of the bolt 122 can be driven freely and rotatably by the input pulley 64, which is driven by the engine 40. as long as the torque on the pulley 64 is sufficient to retain the stove grip between the plates 74 and 80, on the one hand, and plate

70 on the other hand, will thus free rotation of the shafts 58 and

94 continue. As soon as the electric motor is turned off by means of the control switch, however, as will be described, the cams 84 will advance slightly in the direction of rotation so that they again come into full engagement with the cam grooves 78, whereby the spring 86 allows

es to bring the clutch plate 80 into firm contact with the underside of the friction clutch plate 70 and thereby force it into a firm friction grip with the pressure plate 74, whereby the rotation of the shafts 58 and 94 is brought to a sudden stop, which is the main purpose of the above-described clutch and brake mechanism . This device ensures very precise control of the vertical movements of the chair seat supporting top piece 16 and a chair seat and/or backrest each attached to it.

Details of the ball nut 26 are shown in fig. 8, where the screw shaft

24 and the rotatable sleeve 28 are both shown partially cut away. The spiral groove 124 on the shaft 24 has a cross-sectional profile that is complementary to the spiral row of balls 126. The nut 26 is also provided with a spiral groove 128 that is complementary to the groove 124 in the shaft 24, whereby approximately one half of each of the balls 126 is placed respectively in the groove 128 in the nut 26 and groove 124 in the shaft 24. As the nut 26 is turned by the driven sleeve 28 which is connected to and carried by the gear 30, the ball row will be fed from one end of the nut to the other by using the side rudder 130 which is designed in one with the nut. The movement of the balls through the rudder 130 for reception in the materials 124 and 128

will take place in one direction when the screw 24 is raised, and in the opposite direction when the screw 24 is lowered.

Since in practice it cannot be determined in advance how much a therapist may wish to raise or lower the seat carried by the chassis 10, it is assumed that the control means described below for starting and stopping the motor 40 will either be manual or foot controlled, and as long as the control switch is held, the chair will either be raised or lowered, depending on the direction of rotation of the motor 40.

The present construction preferably also includes switch means for limiting the upward movement, such as, for example, the electric switch 132 shown in fig. 3, and which is suitably placed inside the hollow housing which the undercarriage 10 comprises. This switch has a movable heating link which can be engaged by any suitable means which can be moved in the loft direction together with the chair's loft mechanism, such as the hook 134 on the lower end of one of the liner rods 20. A similar switch 136 for limiting the downward movement is suitably placed in the lower part of the housing 10 and is supported by, for example, a suitable angle 138 which is held by the partition wall 32. The operating arm of the switch 136 can be grasped by the hook 134 when the seat-supporting and -supporting means, which are vertically movable, reach the lower limit for desired movement, whereby the motor is switched off and any damage to the drive mechanism is prevented.

THE CHASSIS MOVING MECHANISM ACCORDING TO THE INVENTION.

For adaptation of the chair-seat supporting chassis to linear as well as turning movement in a substantially horizontal plane, for example comprising the supporting floor surface 14, the chassis 10 is designed to preferably include inherent means for generating air pressure and distributing this at least around the circumference of the chassis and release the air from the bottom of the undercarriage downwards towards, for example, the load-bearing floor surface, so that an air membrane is formed between the undercarriage and the load-bearing floor surface. With such an arrangement, the undercarriage as well as the attached chair seat and back can easily be moved either straight forward or in an arc, and also rotated about a mainly vertical axis.

The manpower required to perform such linear or rotary movement of the chair and its chassis can be neglected. By using means for producing such an air film between the undercarriage and the supporting floor surface, a number of advantages are achieved, such as the elimination of any need for pulleys and movement control means for these, or any other similar type of means of support that would allow linear and rotating movement of the undercarriage in relation to the supporting floor surface. When using an air diaphragm which the present invention is aimed at, one of the main advantages is that immediately after the end of the desired movement, the chair base will come to rest on the supporting surface as soon as the power means that produce the compressed air are switched off. This is ensured by the folding chair base, the chair and the occupant, as well as by the fact that the air membrane that is normally formed between the bottom of the base and the supporting floor surface only needs to be quite thin, especially since the air exhaust mechanism to be described, is highly flexible so that a seal is produced which causes an essentially even blowout of air along essentially the entire perimeter of the undercarriage, while the seal is also allowed to adapt to irregularities in the supporting floor surface, at least within reasonable limits. This arrangement according to the invention enables maximum utilization of minimal air pressure and volume by reducing air leakage. In reality, the device also includes an air bearing of a flexible type which provides uniformity on irregular surfaces such as a floor or the like.

The chassis 10 is, preferably in the rear wall, provided with an intake opening 140 which communicates with a chamber 142, which is mainly provided in its center with an air compressor 144, which is preferably of the multi-stage type and provided with peripheral exhaust openings 146. The "impeller" of the compressor is driven by an electric motor 148, which is preferably connected directly to this to cause contraction of the structure. The shell or outer housing of the compressor 144 preferably rests in an elastic gasket 150 to reduce the transmission of vibrations from the compressor to the chassis, as all other parts of the compressor with motor are preferably out of direct or massive metallic contact with the chassis. To further increase stability

of the compressor suspension, there is also an extra elastic seal 15 2 arranged between the compressor shell and the wall 15 4 , which forms the inner boundary of the annular chamber 142.

Both for the sake of appearance and efficiency, the intake of the compressor .144, which is located at the outer end of this, is shielded by a preferably beautiful, porous cover 15 6, which is shown, for example, in fig. 2. It will be understood that instead of being poros tek style material, for example, the cover can be quite thick and also serve as a silencer for the air.

The chamber 142 serves as a collecting chamber, and is connected at the lower end to an annular distribution chamber 158 in the bottom part of the chassis 10, where the upper wall is formed by the circumferential flange 12, and downwards from this flange extend mainly concentric walls 160 and 162 whose lower surfaces preferably lie in the same horizontal plane.

An annular plate 164 extends over the bottom surfaces of the annular walls 160 and 162, and completes the annular chamber 158, with uniform drainage in the circumferential direction through a series of ports 166 which act as inlets for the compressed air.

Said ports are of suitable size and preferably evenly spaced from each other along the circumference to provide a relatively even distribution of compressed air, which is fed downwards from the bottom of the chassis 10 towards a porous flexible membrane 168 which is preferably very flexible. The membrane 168 can be made of any suitable porous and flexible material, such as woven textile, of which muslin or sailcloth are two examples of suitable materials. There are, however, certain porous synthetic resins which can be produced in the form of sheets to serve as membranes. Such resins must be flexible enough that they will easily conform to all reasonable irregularities in, for example, the floor surface 14.

The main function of the membrane 168 is to distribute the air evenly within a relatively limited ring-shaped space directly below the membrane 168 and between this and the floor surface 14, thereby making economical use of the air. By blowing out the air near the circumference of the undercarriage 10, maximum efficiency is further achieved due to that the maximum lever arm is used to lift the undercarriage just above the floor surface to cause easy sliding of the undercarriage over the floor surface on the air membrane which is evenly and uniformly blown out through the porous membrane 168.

In reality, the air distributed by the membrane 168 works to some extent against itself, whereby the air that has just been blown out through the member towards the floor surface forms the air film required to effect the sliding movement of the undercarriage, while the air pressure against the inner surface of the membrane 168 seeks to force the membrane against the floor surface and thereby form a seal against which the air-exhaust membrane must work.

The membrane 168, which is preferably made of flexible, porous sheet material, is itself flat and at the outer edge essentially of a complementary shape to the circumference of the flange 12 of the chassis 10.

In the particular configuration of the chassis 10 circumference which is shown in the plane in fig. 4, it will be seen that the shape of the chassis is mainly circular. To make the membrane 168, a piece of suitable size and shape is cut out of a sheet of material and in the radial direction just slightly larger than the shape of the frame's circumference 12 so that the outer edge 170 can be folded inwards around a clamping ring 172 of metal. The ring 172 is preferably complementary to the outer edge of the circumference 12 of the chassis 10, and is attached to the annular plate 164 by means of a limited number of circumferentially spaced screws 174, which are countersunk in the plate 164 and extend down through threaded holes in the clamping ring 172

as shown in fig. 11.

The main purpose of the screws 174 is to prevent easy separation of the clamping ring 172 from the plate 164, particularly when the plate and the diaphragm 168 mounted on it are attached to the bottom of the chassis circumference 12, and also when removed therefrom. In particular to prevent damage to the flexible sheet-like membrane 168, and also to increase its sealing properties, a ring 176 of felt-like material of a suitable nature, either artificial or natural, is glued to the lower surface of the clamping ring 172, so that the felting is placed between the clamping ring and the circumference of the membrane 168 against which the ring 172 would rest if it were not for the presence of the felt ring 176, especially when the undercarriage is at rest on the floor surface.

The membrane 168 is annular in plane and of essentially uniform width in the radial direction. The inner edge of the membrane is clamped to the lower surface of the annular plate 164 by means of another clamping ring 178, preferably made of metal. This ring is clamped against the inner circumference of the membrane 168 clamped between these by a number of circumferentially distributed screws 180 which are fed through suitable holes in the ring 178 and the plate 164. The screws 180 are threaded nuts 182 which are received in suitable holes or cavities 184 taken out in the wall 32, and is by suitable spot welding etc. locked against rotation in relation to the plate 164.

As shown in fig. 7, another clamping ring 186 is attached to the outer surface of plate 164 so that it is vertically flush with the vertical flange 160 of the chassis 10, the ring 186 being welded or connected in another suitable way to the plate 164, so that it can be processed together with this as a unit. The ring 168 and the plate 164 are provided with several axially aligned holes 188 which are evenly distributed around the circumference of the ring 186, and at least the holes in the ring 186 are threaded.

The annular plate 164, the flexible diaphragm 168, and the various clamping rings 172, 178 and 186 carried by the plate form a unit which can be attached and removed from the chassis 10 as a unified whole, and particularly from its flat bottom 190 which is complementary to the plate 164 surface, as will be easily seen from fig. 7. Assembly and disassembly of said unit on and from the flange 12 of the chassis 10 is preferably carried out from the upper surface of the flange 12.

Two concentric circular rows of head screws 182 and 194 are

fast mainly vertically through the vertical circular flanges which are partially delimited by the annular walls 160 and 162. The heads of the screws 192 and 194 are preferably countersunk in the upper surface of the flange 12, while the screw ends are respectively threaded into the holes 188 in the clamping ring 186 and the threaded holes 196 in the clamping ring 172. In fig. 4 shows, for example, an arrangement of circularly spaced bolts 192 and 194.

By unscrewing the screws 192 and 194 from the clamping rings 186 and 172, respectively, the membrane unit can be easily and simply removed from the bottom surface 190 of the chassis 10, and if, for example, after prolonged use the membrane 168 needs to be replaced, the assembled unit can be returned either to the service warehouse or to the manufacturer for replacement under precise, factory-controlled conditions, whereby

maximum professional execution of the product is ensured. In the meantime, either a new unit or a factory-repaired unit can be inserted into the chair frame in a matter of minutes, thereby returning the frame to full service with respect to the frame's air-blowing function.

Replacement of the membrane 168 at the factory or service depot is carried out quickly and cheaply, as it only requires the removal of a limited number of screws 174 and all the screws 180, whereby the ring 168 is completely free from the plate 164, after which a new sheet of material is inserted by clamping to the plate 164, the new sheet 168 being cut to size at the factory and kept in stock either there or in the service depot, so as to ensure uniformity in placement, quality and final effect for distribution and cushioning purposes.

In operation, there is actually very little wear of the membrane ring 168 because when the undercarriage and that of this carried chair are moved linearly or rotatably in a mainly horizontal plane, for example the floor surface 14, an air film between the floor surface and the undercarriage is maintained by the ring 168. When the chassis is stationary in relation to the floor surface, the filter ring 176 is placed between any metal parts of the chassis 10 and the inner surface of the ring 168. By clamping opposite edges of the ring 168 to the plate 164 by means of clamping rings 172 and 178, those edges become on these rings that lie against the clamped parts of the ring 168 are also preferably somewhat rounded, thereby reducing any cutting or tearing that the ring 168 could otherwise be exposed to when it abuts against the clamping rings 172 and 178. The clamping ring 186 will never, in any case during normal intended operation of the mechanism, come into contact with the diaphragm ring 168.

In order, as far as is reasonable, to ensure that there will be no harmful inclination of the chassis in relation to the floor surface 14, especially during movement in linear directions over such a surface, and especially as a result of a horizontal bump on the upper part of it to the seat 18 attached back, the outer edge of the frame's circumferential flange 12 is provided with one of several possible designs of means intended to prevent any resistance in the movement of the chair frame in relation to the floor surface as a result of an inclination of the frame which may be caused by such movement.

A design of such a means is shown in fig. 2, 3 and 7, where it will be seen that the outer circumference of the annular plate 164 extends beyond the periphery of the flange 12 a limited distance,

and is bent downwards so that it forms a lining flange 198. In order to enhance its lining effect in relation to the floor surface, however, the entire periphery of the flange is covered with a stopped ring 200, preferably prepared from a suitable synthetic resin with self-lubricating properties so that there is close to zero friction , as several commercial varieties of such suitable resin are sold under the trade names "Teflon", "Delrin", "Nylatron" and "Nylon". All these materials have the general property of being self-lubricating so that no friction is caused with a surface with which they are brought into sliding contact.

The lower surface of the ring 200, which preferably lies entirely in a common plane, is just below the lowest surface of the membrane 168 when the chair is at rest, i.e. as shown in fig. 2, whereby the chassis will then rest on the ring 200. It will be understood that in the corresponding enlarged section of the flange 12 in fig. 7, the porous ring 168 is shown, for example, in an inflated state, as when normal air pressure acts on the ring to allow linear or rotary movement of the chassis and the chair attached thereto. It will of course be understood that there will also be a relatively thin air film between the ring 168 and the floor surface 14, which is not shown in fig. 7, but which is nevertheless present during such an operation. When the ring 168 is thus inflated to cause the undercarriage to "float" as described, the ring 200 is spaced just above the floor surface 14 as shown for example in Fig. 7, while if a slight tilting of the undercarriage 10 occurs, the ring 200 will rest against the floor surface and prevent the perimeter of the undercarriage from resisting lateral movement of the undercarriage.

Another design of lining means is shown in vertical section in fig. 9 and in the plane in fig. 4. In this design, a reasonable number of lugs 202 are distributed around the periphery of the end edge of the flange 12, as shown in fig. 4. From fig. 9, it will be seen that each cam is provided with an inner cavity 204 which contains a spring 206 and a hardened metal ball 208 of substantial diameter and which

by any suitable means is prevented from removing from the cavity 204, for example by a change 210 on the cam 202, or the like.

The force of the spring 206 and the diameter of the ball 208, as well as the position of the ball in the cavity 204 are all adjusted so that the ball is normally kept at least slightly in contact with the floor surface at least when the chassis is stationary and the ring 168 is not inflated. When with such a device the ring 168 is inflated so that it occupies the one in fig. 7 position in relation to the floor surface, the position of each ball 208 in the lugs 202 is such that, as soon as there is tilting of the undercarriage during linear or rotary movement in relation to the floor surface 14, one or more of the balls 208 will rest against the floor surface and to prevent any deceleration in the undercarriage's movement in relation to the floor surface.

THE CONTROL DEVICE KNOWN IN AND OF ITSELF.

The operation of the motor 40 in both directions of rotation, as well as operation of the motor 148 which respectively controls the raising and lowering of the seat-bearing top piece 16 and the air compressor 144, is preferably controlled from a single switch box 212 which can conveniently be mounted on the rear surface of the seat back 214 for easy grip by the operator's hand, or in other suitable locations on the chair seat or back, the chassis or remote locations, depending on the needs and wishes of the dentist, operator, assistant or others.

The actual control means preferably comprises a two-way switch 216 which controls the motor 40 for both desired directions of rotation, and a single On-Off switch 218, both of which are shown in the circuit diagram in fig. 12. It is assumed that there is provision for an electric cable to a suitable power source such as an electric socket in the wall or in the floor, and suitable conductors lead from the cable to the switches and switches and from these to the motors in accordance with the connection diagram in fig . 12. The inverter 216 is preferably marked UP, OFF and DOWN, while the switch 218 is marked ON and OFF.

When the switch 218 is moved to the ON position, the motor 148 will start to work and will cause air pressure to be immediately produced for supply to the chamber 142 and from here to the annular distribution chamber 158 for supply to the space immediately below the plate 164 so that the membrane 168 is blown up, whereby an air membrane is produced between the ring and the floor surface. This ring allows easy rotary or linear movement, either in straight or curved paths, of the chassis in relation to the floor surface 14, simply by a limited human force being exerted against, for example, the back 214 of the chair seat 18 and whereby the chair seat and a customer or patient therein can be moved to any new position in the operating room, hairdressing salon, beauty salon or other premises. At the end of such a movement, the switch 218 is set to the OFF position, and the motor 148 stops.

When the engine 148 is stopped, the air pressure in the air circulation system will immediately escape sufficiently for the ring 168 to be blown out, and the chassis 10 is brought to rest by gravity in the new place where it will remain until it is moved again. During the time when the ring 168 is inflated, the chassis 10, the chair seat and the person carried by it can be rotated about a vertical axis or moved linearly in any direction.

The vertical movement of the seat-bearing top piece 16 as well as the chair seat and a person occupying the seat is controlled in opposite directions of movement by means of the turner 216 shown in fig. 1 and 12, and is connected to the reversible circuits for the motor 40 which, as explained above, is of the reversible type. The motor will continue to work in the selected direction as long as the reverser 216 is held in the UP or DOWN position, but as soon as the reverser is set to OFF, the motor will stop. Should lofting or lowering of the chair seat continue to either the upper or lower extreme position, the safety or limitation switches 132 and 136 will come into operation as described above, and automatically disconnect the motor circuit when the arm of one of the switches 132 or 136 is seized by, for example, an exhaust -eren 134 on one of the lining rods 20.

Although the chair shown in the drawings and described above includes a built-in air compressor 144 for providing means by which the undercarriage and everything so; axis, ms it is understood that air under suitable pressure can be supplied from an external source and directed to the annular distribution chamber 158 for example using a suitable control valve. Such a valve can, for example, be solar-enoid-controlled, and if desired operated from the switch 218. The line for supplying such air to the chair base can be of suitable flexibility and rest on the floor surface, and can also be thought of in connection with the flexible electrical line which leads to the chair frame from a power take-off, as described above.

From what has been mentioned above, it will appear that insofar as

the means carried by the chassis for lofting and lowering a chair seat to be carried by the top piece 16 involve laterally spaced vertical bushings 20 on opposite sides of a centrally mounted screw mechanism for lofting and lowering the chair seat, there is no means arranged to effect turning between

the chair seat 18 or the top piece 16 which supports this on the underframe 10. Another reason for not providing for rotatable movement of the chair seat in relation to the underframe is that with the device just mentioned it is possible to direct the movement of the underframe 10 in relation to the supporting floor surface for for example by grasping the back 214 attached to the chair seat. However, turning the chair seat 18 to any desired position about a vertical axis is achieved quite easily, simply by supplying compressed air to the diaphragm ring 168 so that an air membrane is created under the chassis close to the floor surface , either for an instantaneous period or longer, whereby the chair base is allowed to slide smoothly and easily over the floor surface, either linearly or in a rotary motion about a mainly vertical axis. Stabilization of such movement of the chair base is achieved by means of any number of floor-attached stabilizing means near the lower edge of the base, such as, for example, the circumferential ring 200 or those in fig. 4 and 9 showed lugs 202.

Claims (5)

1. Movable furniture base, preferably for chairs, provided with means which, when activated, allow the base to float during horizontal movement on a membrane of air between the base and the floor, characterized in that said means comprise as the last link an easily replaceable ring-shaped membrane unit (164, 168 . 2. Furniture base as specified in claim 1, characterized in that the membrane unit (164, 168, 172, 176, 178, 186) is adapted to a correspondingly designed air-conducting annular distribution chamber (158) in the circumference of the base so that the membrane unit forms the bottom part of the annular chamber. 3. Furniture base as stated in claims 1 and 2, characterized in that the membrane unit comprises an annular plate (164) provided with ports (166) which carries three clamping rings (172, 178, 186) and one between the rings (178) and (172) expanded ring-shaped air-permeable membrane of soft and flexible sheet-shaped material. 4. Furniture base as stated in any of the preceding claims, characterized in that the outer peripheral part of the membrane unit is designed with a downward sliding lining edge (200) touching the floor. 5. Furniture base as specified in claim 4, characterized in that balls (208) are inserted into the guide edge (200) and spring-pressed (206) against the floor.