baber/WOPTO huggingface dataset:
Patent GB-897382-A (GB)
Title: Improvements in or relating to washers and methods of bolting using such washers
Inventor: HAWKINS LEONARD CHARLES
IPC: F16B7/18
Filed: 1957-12-13
Abstract: 897,382. Tube &c. joints. SIDDALL & HILTON Ltd. Dec. 12, 1958 [Dec. 13, 1957], No. 38738/57. Class 99(1). [Also in Group XXV] An annular washer 10 for use between members 16, 18 connected together by a bolt 20 has a groove 12, 14 in each end face to embrace the adjacent member and prevent relative turning movement between the members which may be tubes, bars, rods &c. of square or circular cross-section. The angular disposition of the grooves is dependent on the angle of intersection of the members. For thin-walled tubes, the bolt head and nut may clamp the internal walls of the tubes.
Patent GB-936885-A (GB)
Title: Method of degassing melt of light metal
Inventor: KURFMAN VIRGIL BENSON
IPC: C22B9/04
Filed: 1961-11-01
Abstract: A molten body of light metal of the group consisting of aluminium, magnesium or alloys thereof, where Al or Mg is at least 75% by weight, is degassed by bubbling a gas, e.g. H2, N2, He, A, CO2, CO, CH4, air, natural gas, or mixtures thereof with up to 10% by volume Cl2, first into or through a denser molten saline flux layer located under the molten metal, and then through the molten metal.  For aluminium or alloys thereof, the flux used may consist of 70% BaCl2 and 30% NaCl; for magnesium or alloys thereof, the flux may consist in specified amounts of four or more of the following salts: KCl, MgCl2, MgO, BaCl2, CaF2, CaCl2, MnCl2.
Patent GB-915379-A (GB)
Title: Improvements in or relating to devices for providing heated air in vehicles
Inventor: DELANEY CYRIL TERENCE
IPC: B60H1/03
Filed: 1960-11-16
Abstract: 915,379. Ventilating vehicles. GALLAY Ltd. Oct. 31, 1961 [Nov. 16, 1960], No. 39391/60. Class 137. A vehicle heating system comprises a heatexchanger 19, through which fluid coolant from the cooling system of the vehicle driving engine is circulated, located in a duct 16 for leading air to the vehicle, and an electric heating element 26 mounted in the same duct. As shown, electric current for the heating element and for a motor 23 driving a fan 22 to force air through duct 16 is supplied by an engine-driven generator 24, through switches 30 and 25, respectively. The heater current also passes through a thermal switch 27 mounted in the coolant return hose 14 between the engine 11 and the radiator 12, this switch being closed below a predetermined temperature (about 70‹ C.) and open above it. Thus, the electric heater provides for vehicle heating when the engine is started, and before the engine coolant has warmed up to the predetermined temperature. The heated air may be passed to the interior of the vehicle or to windscreen demisting devices.
Patent GB-1308846-A (GB)
Title: Acylated arylhydrazino-2-imidazolines processes for their manufacture and their use as electroparasiticides
IPC: C07D233/52
Filed: 1971-08-23
Abstract: 1308846 Acylated aryl hydrazino-2-imidazolines BAYER AG 23 Aug 1971 [22 Aug 1970 12 May 1971] 39394/71 Heading C2C The invention comprises compounds of formula and salts thereof, in which R<SP>1</SP> is H; a straight or branched alkyl radical with 1-17 carbon atoms which may be substituted with fluorine, chlorine, bromine, alkyloxy, alkylthio, aryl, aryloxy, halo-aryloxy, arylthio or haloarylthio; an alkenyl radical with 2-6 carbon atoms optionally substituted with phenyl; a cycloaliphatic radical with 3-6 carbon atoms; a phenyl radical which may be substituted with one or more of fluorine, chlorine, bromine, carboxyl, carboxyalkyl, hydroxyl, nitro, alkyloxy, alkylthio, alkyl, alkenyl with 2-4 carbon atoms, phenyl, amino, alkylamino, dialkylamino, or acylamino; naphthyl; or fuoryl; and R<SP>2</SP> is one or more of H, fluorine, chlorine, bromine, nitro, carboxyl, carboxyalkyl, hydroxyl, lower alkyloxy, alkyl or trifluoromethyl. The compounds may be prepared by reacting the corresponding phenylhydrazino - 2 - imidazoline with (a) R<SP>1</SP>-CO-Y where Y is F, Cl, Br or N 3 , (b) R<SP>1</SP>-CO-XR where X is O or S and R is alkyl, aryl or acyl, or (c) R<SP>1</SP>-CO-XH, optionally in the presence of a carbodiamide. Salts may be formed using hydrochloric, phosphonic, sulphuric, carboxylic, or sulphonic acids. The compounds are acaricides.
Patent GB-1007584-A (GB)
Title: Improvements in or relating to benz[c,d]indole derivatives and the manufacture thereof
IPC: A61Q17/04
Filed: 1962-07-09
Abstract: The invention comprises compounds of the general formula <FORM:1007584/C2/1> wherein R is hydrogen or C1 to C8 alkyl, R1\t is hydrogen, C1 to C4 alkyl, phenyl, hydroxyphenyl, alkoxyphenyl wherein alkoxy is of 1 to 4 carbon atoms, or halophenyl, R2 is hydrogen, alkanoyl of from 1 to 4 carbon atoms, benzyl or halobenzyl which can be substituted with alkyl or alkoxy of 1 to 4 carbon atoms, or alkyl of from 1 to 4 carbon atoms, R3 is hydroxy, benzyloxy, halogen, or alkyl or alkoxy of from 1 to 4 carbon atoms, and n is zero, 1 or 2. The compounds may be prepared by subjecting the 5-oxo group of a compound of the general formula <FORM:1007584/C2/2> wherein R, R1, R2, R3 and n are as defined above, to a Huang-Minlon reduction and, in the case where R2 in the starting material represents an alkanoyl group, optionally N-acylating the acid so produced.  The acids may be esterified by conventional procedures, for example, via the acid chlorides, and the resultant esters may be purified and then hydrolysed to the acids, resulting in upgrading of the acids.  The compounds of the invention, wherein R is H, may be decarboxylated by heating to give compounds of the general formula. <FORM:1007584/C2/3> wherein R1, R2, R3 and n are as defined above. The compounds of the invention, wherein R is H, may also be esterified in accordance with U.S.A.  Specification 2,220,521, to form betathiocyanoethyl esters. The Huang-Minulon reduction is performed by conversion of the acid or the ester to the corresponding salt, followed by reduction with hydrazine hydrate. Many suitably values of R, R1, R2 and R3 are specified.  Examples are given, including examples of the hydrogenolysis of acids containing a 6- or 8-benzyloxy substituent to give the corresponding free hydroxy compounds.ALSO:Sun-screen lotions may incorporate, as ultraviolet absorbents, compounds of the general formula <FORM:1007584/A5-A6/1> wherein R is hydrogen or C1 C8 alkyl, R, is hydrogen, C1 to C4 alkyl, phenyl, hydroxyphenyl, alkoxyphenyl wherein alkoxy is of 1 to 4 carbon atoms, or halophenyl, R2 is hydrogen, alkanoyl of from 1 to 4 carbon atoms, benzyl or halobenzyl which can be substituted with alkyl or alkoxy of 1 to 4 carbon atoms, or alkyl of from 1 to 4 carbon atoms, R3 is hydroxy, benzyloxy, halogen, or alkyl or alkoxy of from 1 to 4 carbon atoms, and n is zero, 1 or 2 (see Division C2).
Patent GB-1395992-A (GB)
Title: Photographic roll film cameras
IPC: G03B17/42
Filed: 1972-08-24
Abstract: 1395992 Roll film cameras EASTMAN KODAK CO 24 Aug 1972 [24 Aug 1971] 39432/72 Heading G2A A roll film camera, for use with films having one perforation per picture area, has actuating means 22 for sequentially cocking a shutter drive means 48 and then actuating film transport means 52, 60, a movable perforation-sensing pawl 90, 96, which co-operates with latching means to arrest the film-transporting movement of actuating means 22, and means for retracting the pawl from an engaged position during a shutter-cocking movement of actuating means 22. Fig. 1 shows the camera elements after an exposure has been made. The actuating means is a slide 22, normally held in the position shown by a spring 34. When this is moved in the direction of arrow 24, a cam surface 26 cocks the shutter drive member 36 by engaging a pin 46 thereon and pivoting the drive member anti-clockwise, against a spring 40, until an arm 48 of the drive member latches under the end of a member 66, and is so retained Fig. 2 (not shown). At the same time a tab 30 on member 22 engages a control member 102 and pivots it clockwise, which in turn engages an intermediate member 70, pivoting it anti-clockwise, which in turn engages and pivots anti-clockwise a sensing member 90. This member is slidably pivoted on a pin 92, so that this movement causes a pawl arm 96 to be withdrawn from a perforation 108 in the film 14. The film transport is effected by a rack member 52 whose right hand end is urged upwards by a spring 56. In the Fig. 1 position this end is held downwards, against the spring, by a stud 58 on drive member 36. As member 36 is cocked, however, stud 58 no-longer engages member 52, so that its end is urged upwards. This brings it into the line of action of a lug 32 on slide 22, so that when this is moved in direction 24 for a second time, rack member 52 engages with a gear sector 60 which, via further gears 62, 64, winds on the film take-up spool 18. When the next perforation reaches pawl 96, it is entered by the pawl under the action of spring 98, and drawn to the left. This disengages its end 100 from tab 80 of member 70, which is then pivoted clockwise by spring 74 until a further tab 86 engages teeth 28 on slide 22 to prevent further movement, Fig. 3. When an exposure is made, the camera release (not shown) pivots latch 66 clockwise, which releases member 36 to be driven clockwise, arm 42 then operating the shutter mechanism (not shown). At the same time arm 50 engages tab 84 of member 70, pivoting it anticlockwise so that tab 86 is disengaged from teeth 28, and stud 58 pushes rack 52 downwards again so that it disaligns from lug 32. Pawl 96 remains in the perforation, and the Fig. 1 position is reached once more.
Patent GB-341246-A (GB)
Title: New process in connection with the electro-deposition of metals
IPC: C25D1/22
Filed: 1929-12-27
Abstract: 341,246. Electrolysis. COLES, S. O. COWPER-, Rossall House, Thames Street, Sunbury-on-Thames. Dec. 27, 1929, No. 39525. [Class 41.] Preparing surfaces; electrodes, moving; moulds.- A rotating mandrel is coated in order to facilitate removal of metal deposited thereon with a 0À05-0À5 per cent solution of bees-wax in turpentine to which is added 1 per cent of carbon bisulphide. The cylindrical surface of the mandrel is preferably of copper or brass, highly polished. The deposited metal may be removed axially as a tube or it may be divided on a line parallel to the axis and removed as sheet.
Patent GB-864153-A (GB)
Title: Improvements in and relating to terminals or connecting means for electrical cables and wires
Inventor: GRIFFIN ARTHUR
IPC: H01R9/18
Filed: 1958-12-09
Abstract: 864,153. Binding posts; terminal blocks. BLACKWELL & CO. Ltd., F. C. Oct. 8, 1959 [Dec. 9, 1958], No. 39616/58. Class 38 (1). A terminal assembly comprises a conducting body of channel cross-section having a flat underside and two aligned channel parts 2 separated by recesses formed by stamping or pressing out opposite portions 3 from the channel sides, and one or more conducting clamping parts 5 of cruciform shape having lateral extensions 6 cooperable with the body recesses and having holes 7 which can be aligned with threaded holes 4 in the body portions 3 to receive clamping screws (not shown). Two or more terminal assemblies may be mounted on an insulating base formed with an insulating barrier between adjacent terminals (Fig. 5, not shown).
Patent GB-1198583-A (GB)
Title: Stabilisation of 1,1,1-Trichloroethane
Inventor: CORREIA Y
IPC: C23G5/028
Filed: 1968-08-20
Abstract: 1,198,583. Stabilization of 1,1,1-trichloroethane. PRODUITS CHIMIQUES PECHINEY-SAINT-GOBAIN. 20 Aug., 1968 [17 Nov., 1967], No. 39831/68. Heading C2C. [Also in Division C5] 1,1,1-Trichloroethane is stabilized by incorporation of trioxane in association with an aliphatic alcohol and/or an epoxide which is liquid at ambient temperatures. Optional classes of additional additives are listed, including specifically nitromethane and acetonitrile.
Patent GB-1166606-A (GB)
Title: Glass Compositions
IPC: C03C4/12
Filed: 1966-09-08
Abstract: 1,166,606. Luminescent materials. OWENSILLINOIS Inc. 8 Sept., 1966 [9 Sept., 1965], No. 40086/66. Heading C4S. [Also in Division C1]  A luminescent glass article containing a multi-colour phosphor combination grown in the surface of the glass is formed from a glass composition consisting essentially of the following oxides in weight per cent: A. SiO 2  40-55; ZnO 25-40; Na 2 O 11-18; Li 2 0 0-3; CaO 0-4; SrO 0-10; MgO 0-10; Al 2 O 3  0-4; MnO 0-2; Sb 2 O 3  0-2; and wherein the total CaO + Al 2 O 3 does not exceed 4%. B. SiO 2  38-55; ZnO 25-45; K 2 O 13-20; Li 2 O 0-3; CaO 0-10; BaO 0-10; MgO 0-10; SrO 0-10; Al 2 O 3  0-5; ZrO 2  0-6; WO 3  0-2; MnO 0-2; Sb 2 O 3  0-2, and wherein the total CaO + Al 2 O 3  + BaO does not exceed 10%. C. SiO 2  40-55; ZnO 25-40; Na 2 O 2-12; K 2 O 5-12; CaO 0-3; BaO 0-3; MgO 0-2; Al 2 O 3 0-4; MnO 0-2; Sb 2 O 3  0-2, and wherein the total Na 2 O + K 2 O is at least 10 but not more than 24 weight per cent, upon the surface of which has been deposited and heated in situ at least one layer containing an activator for the phosphor in the glass surface layer, the heat treatment(s) being up to but not substantially above the Littleton softening point of the glass until there has been formed at least one crystalline, activated phosphor layer, the colour of luminescence of which depends on the incident electron energy. Solutions of Zn salts and/or manganous (or titanium or uranium) salts may be applied to surface crystallized or crystallizable glasses to produce a multilayer structure of crystalline ZnSiO 4  phosphors with Mn + 2 (or Ti + 4, U<SP>+</SP> 4) activator luminescing green and blue at low and high electron energies respectively for example. Willemite and spinel structures and a wide range of heat treatment temperatures are disclosed. Emissions instanced are at 5250 Š, to 5300 Š and 3850 Š. Additional additives may be Li 2 O, TiO 2 , B 2 O 3 , P 2 O 5 , SrO,Cr 2 O 3  and ZrO 2  (for colouring purposes up to 3% by wt. of cobalt, nickel or chromium oxides may be included. A large number of glass examples are disclosed.
Patent GB-986333-A (GB)
Title: Improvements relating to water closets
Inventor: STOTT CHARLES KENNETH
IPC: E03D11/08
Filed: 1962-10-24
Abstract: 986,333. Sanitary closets. ARMITAGE WARE Ltd. Oct. 22, 1963 [Oct. 24, 1962], No. 40216/62. Heading E1C. In a water closet for connection with a flushing cistern or flush valve, the connection 11 delivers water via a single port 15 to direct the water around the basin 10 in one direction. The connection may have a further port or ports to direct water downwardly.
Patent GB-916240-A (GB)
Title: Improved piston ring
IPC: F16J9/20
Filed: 1961-11-10
Abstract: 916,240. Piston rings. FORD MOTOR CO. Ltd. Nov. 10, 1961 [Dec. 2, 1960], No. 40289/61. Class 122 (1). A piston-and-ring assembly comprises a piston ring 22 (Fig. 2) having line contact at 30, 35 with each side of the ring groove 23 and comprising a first flange 26 and a second flange 27 integrally connected by a part having a cylinder wall engaging surface 28. The ring is split and made from spring steel, the flanges 26 and 27 diverging radially inwardly. In a modification, Fig. 1 (not shown), one of the flanges is corrugated radially. In the modification shown in Fig. 3, the ring 31 comprises a third flange 36 integrally connected to the first flange 34 and diverging radially outward therefrom so that the ring is in line contact with the sides of the groove 32 at 40 and 41.
Patent GB-832298-A (GB)
Title: Carburetor
IPC: F02M21/02
Filed: 1957-12-30
Abstract: 832,298. Carburetting apparatus. BENDIX AVIATION CORPORATION. Dec. 30, 1957 [Jan. 17, 1957], No. 40323/57. Classes 7(2) and 7(3) In a carburetter (e.g. a liquefied petroleum carburetter) comprising an induction passage 10 with a throttle 14 mounted therein and an idle system including an idle conduit connected to the source of fuel feeding the carburetter and having a port 30 opening in the induction passage downstream of the throttle, the idle conduit is connected to a source of higher pressure than exists at the idle port during operation of the engine such as the induction passage upstream of the throttle by a conduit 38 in which is disposed a valve 42 controlled as a function of the throttle position and closing the latter conduit when the throttle is in closed and fully opened positions and opening this conduit when the throttle is in a predetermined range of intermediate positions. When the valve 42 is open air bled into the idle conduit 28 causes the flow of fuel through the port 30 to cease. As shown, the fuel enters by a conduit 24 and is controlled by a main metering restriction 26 and coacting valve 27.
Patent GB-1276553-A (GB)
Title: Lamp with optical system for projecting a beam
Inventor: WESTLUND ARNOLD E
IPC: F21V9/12
Filed: 1969-08-12
Abstract: 1276553 Lamps GTE SYLVANIA Inc 12 Aug 1969 [14 Aug 1968] 40336/69 Heading F4R A lamp, particularly a vehicle headlamp, of the kind in which an optical element, such as a lens or ellipsoidal reflector, forms an image of a light source at the rear focal plane of a projection lens has a gate disposed at the rear focal plane to define a sharp cut-off along part of the edge of the projected beam and a filter spaced from the gate at an out-of-focus position, the filter having zones of different densities to provide a gradual cut-off along the remaining part of the edge of the beam.
Patent GB-1205920-A (GB)
Title: Installation including one or more exhaust stacks
Inventor: WAKONIG FRIEDRICH
IPC: E04H12/28
Filed: 1969-08-12
Abstract: 1,205,920. Chimneys. WAAGNER-BIRO A.G. 12 Aug., 1969, No. 40367/69. Heading F4J One or more gas exhaust stacks 3 are mounted alongside and secured to a vertical tower 1 to be supported thereby whilst permitting easy access to them. The tower may be formed as a tubular, concrete or steel mast (not shown) or of trusswork 2 secured by steel cables (not shown). The metallic stacks 3 are formed in sections interconnected by bellows joints 10, the sections being secured to the tower at their upper ends to allow their downward expansion, by brackets (not shown) or by passing through apertures in supporting platforms 12 which are mounted on the tower. Guide elements 13 extend from the tower to engage the lower ends of the exhaust stack sections to help retain them in position. The tower may be mounted in a fixed framework (Fig. 1, not shown) or on a ball and socket joint 5, 6 which allows the tower to tilt in response to lateral wind forces to reduce the bending stresses to which the tower would otherwise be subject. In this latter embodiment rigid arms 7, horizontally pivoted to the base of the tower, extend outwardly into slotted foundation members 8 to prevent the tower turning about its vertical axis when lateral wind forces act on it. Any desired number of stacks may be mounted against a given side of the tower. An access lift or ladder may be provided within the tower, and warning lights or sirens on it.
Patent GB-1242970-A (GB)
Title: NEW BENZO[b]THIOPHENEACETIC ACID COMPOUNDS AND METHODS FOR THEIR PRODUCTION
IPC: C07D333/12
Filed: 1969-08-14
Abstract: 1,242,970. Benzo[b]thiophene derivatives. PARK DAVIS & CO. 14 Aug., 1969 [15 Aug., 1968; 25 June, 1969], No. 40723/69. Heading C2C. The invention comprises compounds of formula RR<SP>1</SP>CHCO 2 H and their pharmaceutically acceptable salts, wherein R is H or C 1-4  alkyl, and R<SP>1</SP> is one of the following radicals in which each Ph may be halogen- or methylsubstituted, R<SP>11</SP> is Ph or cyclohexyl and X is the benzo[b]thiophene nucleus: 4-Ph-2-X, 7-R<SP>11</SP>- 3-X, 7-R<SP>11</SP>-4-X, 2-Me-7-Ph-4-X, 2-Ph-6-X and 3- or 4-Ph-7-X. These compounds are prepared by hydrolysing compounds of formula RR<SP>1</SP>CHY, in which Y is a group hydrolysable to CO 2 H. Starting materials.-Details are given for the preparation of the following: 2-benoylthiophenes, ethyl 3 - phenyl - 3 - (2-thienyl) acrylates and -propionates, 3-phenyl (or methyl or cyclohexyl - 3 - (2 - thieny]) propan - 1 - ols, 3 - phenyl (or methyl or cyclohexyl) - 3 - (2 - thienyl)propyl bromides and cyanides, 4- phenyl (or methyl or cyclohexyl) - 4 - (2 - thienyl)butyric acids, 7 - phenyl (or methyl or cyclohexyl) - 6,7 - dihydrobenzo[b]thiophen- 4(5H) - ones, ethyl 7 - phenyl - 6,7 - dihydrobenzo[6]thiophene - 4 - acetates, ethyl 7- phenyl) or cyclohexyl)benzo[b]thiophene- 3 and 4 - acetates, 2 - phenacylthiotoluenes, 3 (or -4) phenyl - 7 - methylbenzo[b]thiophenes and their 7 - bromomethyl and 7 - cyanomethyl analogues, 7 - (alpha - cyanoalkyl) - 3 (or 4)- phenylbenzo[b]thiophenes, 3 - (alpha - cyanoalkyl) - 7 - phenylbenzo[b]thiophene, 3 - methyl- 7 - phenyl - and 2 - methyl - 4 - phenyl - benzo [b]thiophenes and their bromomethyl and cyanomethyl analogues, 6 - bromo (and cyano) methyl - 2 - phenylbenzo[b]thiophenes, (2 - biphenylylthio)acetone, ethyl 3 - oxo - 4 - [(2- phenyl or 2-cyclohexyl)phenylthio]butyrate, 2- (3 - carboxypropionyl) - 5 - methylthiophene and its methyl ester, 2-(3-carboxypropyl)- 5- methylthiophene.
Patent GB-1037858-A (GB)
Title: Method and composition for cleaning resin coated substrates
IPC: C11D7/50
Filed: 1964-10-07
Abstract: Compositions for stripping resinous deposits from substrates comprise hydrofluoric acid, an inert organic solvent, and a hydroxyaromatic compound, e.g. phenol, naphthol or cresol (see also Specification 1,037,857.  The compositions are substantially anhydrous, i.e. they contain not more than 3 wt. per cent of water.  Suitable solvents are methylene chloride, alpha-omega-dichloro - 62- 6 - alkanes, 1,1 - dichloroethane, 1,2- and 2,2 - dichloropropane, perchloroethylene, propane and butane, monofluoroperchloroethane, monofluoroperchlorobutane, monofluoroperchloropropane, and monofluoromethane. A paraffin wax may also be present.
Patent GB-868229-A (GB)
Title: Improvements in and relating to automatically actuated clutches
IPC: F16D48/02
Filed: 1958-12-19
Abstract: 868,229. Clutch control. FICHTEL & SACHS A.G. Dec. 19, 1958 [Feb. 6, 1958], No. 41090/58. Class 80 (2). In a motor vehicle clutch control wherein the resistors of an electromagnetically operated clutch are actuated or, as shown, a spring- engaged clutch is disengaged during gear shift, by a servomotor actuated by pressure or depression, equalization of pressure difference in the servomotor, and hence the rate of engagement, is effected in dependence on depression in the choke of the usual engine carburetter 9 which depression is substantially proportional to engine power, to prevent excessive slip or premature engagement. Manifold depression, vehicle acceleration, engine speed and throttle setting may also assist. As shown, a servomotor 1 controlling a clutch lever 2 is evacuated to declutch by inlet manifold depression through pipes 7, 4 when an electromagnetic valve 12 in a block 5 is actuated by movement of a gear shift lever 6, and is vented for engagement, when the lever 6 is released, through pipes 7, 15 and a valve 14 which opens for initial pressure balance against an adjustable spring 16, the usual bleed hole 18 providing slow residual balance. To control the rate of residual balance and thereby the rate of final clutch engagement the valve 14 is also opened, through a stem 20, against the spring 16, in response to depression in the choke of the carburetter 9 which acts on a diaphragm 19 through a pipe 8 communicating with a bore 10 positioned in the choke as shown in Fig. 2. The pipe 8 may be restricted at 23 to retard the operation. A sealing diaphragm 21 guides the stem 20. In Fig. 3(a), not shown, the stem 20 comprises a spring along part of its length above the diaphragm 21 which tends to overcome the spring 16 and is axially compressed in response to inlet manifold depression acting on a further diaphragm motor. This combination ensures engagement which is not too gradual at low speeds when, at sudden wide throttle opening, both choke and inlet manifold depressions are low, and is not too quick at high speeds when, at sudden throttle opening, both depressions are high. In Fig. 4, not shown, a pivoted inertia mass, subject to vehicle acceleration, acts on the diaphragm which is loaded by choke depression. Choke depression may also be used in conjunction with known throttle valve or speed governor connected, inlet manifold depression and vehicle acceleration devices.