baber/WOPTO huggingface dataset:
Patent ZA-864364-B (ZA)
Title: Heat sealable multilayer films with low permeability to gas and their use as packaging material
Inventor: SCHINKEL INGO
IPC: C08L23/04
Filed: 1986-06-11
Abstract: Heat sealable, composite film comprising a polypropylene film, at least one adhesion layer, at least one gas-barrier layer and at least one heat-sealing layer of a linear statistical ethylene copolymer of low density.
Patent ZA-866825-B (ZA)
Title: Azolyl-derivatives endowed with antifugal activity
Inventor: COLLE ROBERTO
IPC: A61K/
Filed: 1986-09-08
Abstract: Disclosed are compounds, having the general formula: wherein:m = 0, 1, 2; n = 0, 1 with the condition that when m = 0, also n = 0;p = 0, 1; q = 1, 2;X is either oxygen or sulphur;A = N, CH;R is H, CH₃, F;R₁ is selected from chlorine, bromine, fluorine, CF₃, phe­nyl, C₁-C₂-alkoxy, C₁-C₂-haloalkoxy, alkylthio, haloalkyl­thio, wherein the halogen is Cl, Br, F;R₂ is selected from H, chlorine, bromine, fluorine;R<sub>f</sub> is selected from the group formed by alkyls containing from 2 to 4 carbon atoms, and containing at least 4 atoms of halogen selected from F, Cl and Br, of which at least 3 are F atoms; alkenyls and alkynyls containing up to 4 carbon atoms, containing at least 2 F atoms and, optionally, other halogens selected between Cl and Br.
Patent ZA-881755-B (ZA)
Title: Polyolefin molding composition
IPC: C08K5/00
Filed: 1988-03-11
Abstract: A polyolefin molding composition, in particular based on LLDPE, containing a fluorine-containing polymer together with a wax, has a broad processing range in which no surface defects occur. The throughput on extrusion is greatly increased.
Patent ZA-882329-B (ZA)
Title: Apparatus for the controlled freezing of viscous liquids
IPC: F25C1/00
Filed: 1988-03-31
Abstract: A device for the controlled deep freezing of viscous liquids by means of a low boiling liquified gas is used for producing drops from the liquid, which are frozen to pellets in a liquid nitrogen bath. The device includes a container arranged above the bath to hold the liquid to be frozen. The bottom of the container consists of two drip plates which can be moved in relation to each other and are provided with bores.
Patent ZA-882899-B (ZA)
Title: Nitrification-inhibiting agent
IPC: C05G3/90
Filed: 1988-04-25
Abstract: 1. Nitrification-inhibiting agent, characterised in that it consists of a) dicyandiamide and b) guanylthiourea and/or ammonium thiosulphate, as well as possibly c) ammonium phosphate.
Patent ZA-885867-B (ZA)
Title: Process for polymorphic crystalline form conversion
Inventor: BEHME ROBERT JAMES
IPC: C07D401/14
Filed: 1988-08-10
Abstract: "A process for conversion of one polymorphic crystalline form of buspirone into its other polymorphic crystalline form is described.
Patent ZA-895310-B (ZA)
Title: Herbicidal compounds and compositions containing them
Inventor: DESBORDES PHILIPPE
IPC: C07C317/14
Filed: 1989-07-12
Abstract: Herbicides of formula:   <IMAGE> I  in which: n=0,1, 2 f=0,1 A is chosen from the groups  <IMAGE>   in which: Ar is chosen from the groups   <IMAGE> Ar-1  <IMAGE> Ar-2  <IMAGE> Ar-3  <IMAGE> Ar-4  B is chosen from optionally substituted C1-C10 alkyl and C3-C10 cycloalkyl groups or from the groups   <IMAGE> B1  <IMAGE> B2  <IMAGE> B3 <IMAGE> B4
Patent ZA-898531-B (ZA)
Title: Forming metal matrix composite bodies containing threedimensionally interconnected co-matrices
Inventor: KENNEDY CHRISTOPHER ROBIN
IPC: C04B35/80
Filed: 1989-11-09
Abstract: The present invention relates to the formation of a metal matrix composite body by the spontaneous infiltration of a molten matrix metal (6) into a three-dimensionally interconnected material (8) Moreover, the three-dimensionally interconnected material (8) may contain filler material within at least a portion of its porosity. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with a filler material and/or a three-dimensionally interconnected material(8) and/or a matrix metal at least at some point during the process, which permits molten matrix metal(6) to spontaneously infiltrate the three-dimensionally interconnected material (8) and any filler material contained within at least a portion of the porosity of the three-dimensionally interconnected material.
Patent ZA-913084-B (ZA)
Title: Heterocyclic compounds their preparation and use
Inventor: JORGENSEN ANKER STEEN
IPC: C07C323/12
Filed: 1991-04-24
Abstract: Novel [1]benzothieno[2,3-b]pyrazine-2,3(1H,4H)-diones or tautomeric forms thereof of the general formula (I)   <IMAGE> (I)  wherein R1, R2, R3 and R4 independently represent hydrogen, halogen, alkyl, alkoxy or trifluoromethyl. The compounds are useful for treating a central nervous system ailment associated with the NMDA receptor-associated glycine site.
Patent ZA-926651-B (ZA)
Title: Compositions and methods for controlling the growth of microbials in aqueous media.
Inventor: JONES RONALD L
IPC: A01N43/90
Filed: 1992-09-02
Abstract: Compositions and methods are disclosed for sanitizing aqueous media, which combine a chlorine-source composition and a glycoluril-source composition. The compositions are added together or separately, continuously or periodically, and by any of a variety of methods. The glycoluril compound stabilizes the chlorine and prolongs its useful life as a microbicidal agent.
Patent AT-412521-B (AT)
Inventor: LOSBICHLER PAUL DR
IPC: H01H37/48
Filed: 2003-03-10
Granted: 2005-03-25
Abstract: The tube (8) of the temperature sensor (7) extends all the way across the top of the circular heating element (1). It contains a first long rod (L1.9) which expands when heated and presses on the end of a short rod (L2.9) which extends into a housing (10). The housing contains electrical contacts (11,12) which may be pushed together by expansion of the first rod. The two rods have different coefficients of expansion to compensate for expansion of the housing. The housing may be rotated as a knob (18) to alter the setting of the switch.
Patent GB-2088862-B (GB)
Title: Intermetallic compounds and their production
IPC: C08F4/42
Filed: 1981-11-24
Granted: 1985-03-20
Abstract: A 1-olefin is polymerised or copolymerised using a catalyst system comprising a mixture of cocatalysts, one of which is a halide activated intermetallic compd. comprising the reaction product of a polymeric transition metal oxide alkoxide a reducing metal of higher oxidation potential than the transition metal. Low density polyethylene for blown or cast film, wire and cable coating, coextrusion and injection or rotational moulding is produced having a broader molecular wt. distribution and higher melt index.
Patent GB-2198109-B (GB)
Title: Lifting device
Inventor: DALSBO OLA KRISTOFFER
IPC: B66C23/82
Filed: 1986-11-28
Granted: 1990-01-17
Abstract: A crane has a generally vertical, pivoting crane shaft (17) which supports a crane boom (23, 24) which can be raised and lowered by means of a hydraulic cylinder (28). The crane shaft (17) is supported at its lower end by a pivoting arm (20) which is actuated by a power unit (31), the crane shaft (17) being capable of being turned about its own longitudinal axis. Changes in the angle of the boom are reduced by the axis of the crane shaft (17) being tilted at a narrow angle by the supporting arm (20). The rotating movement of the crane shaft (17) is controlled by a link arm (37) which is firmly attached at one end and joined to an arm (36) which protrudes from the side of the crane shaft (17). <IMAGE>
Patent GB-2200677-B (GB)
Title: Hinge bolt assembly
Inventor: MCGILL JOHN
IPC: E05B15/02
Filed: 1987-02-04
Granted: 1991-08-07
Abstract: A hinge bolt assembly comprises a hinge bolt 6 for driving into an edge of a door 1 leaving a head end portion 7 projecting, a socket member adapted 8 fully to enclose the head portion 7 of the bolt 6 for recessing into a door frame 3, a fixing plate 10 secured to the socket member 8, and bolt means 11 for passing through the fixing plate and a said door frame for tightening at the secure side of such doorway. <IMAGE>
Patent GB-2286629-B (GB)
Title: Bolt for a door,window or the like
Inventor: PREVOT GERARD
IPC: E05C9/04
Filed: 1995-02-10
Granted: 1997-07-23
Abstract: The invention relates to a lock fitting such as a bolt lock or similar, comprising a casing 6 extending at the rear side of a face-plate 7 and containing an actuating mechanism 5 provided with at least a key member 11 capable of acting on at least locking means such as a dead bolt or another locking organ. This lock fitting is characterized in that it includes means 16 for immobilizing the key member 11 in axial translation inside said casing 6 and acting in a direction perpendicular to the longitudinal median plane 12 of this key member 11 under the action of actuating means 17 accessible from the inner face 18 and/or the outer face 19 of the casing 6. As shown in fig 3, detents 20, 21 are urged against the member 11 by the action of screws 27, 29. <IMAGE>
Patent GB-2288067-B (GB)
Title: Method of fabricating a semiconductor device,method of cleaning a crystalline surface of a semiconductor,and semiconductor device
Inventor: KIZUKI HIROTAKA
IPC: H01S5/00
Filed: 1995-03-24
Granted: 1997-11-12
Abstract: In fabricating a semiconductor device, a semiconductor layer containing Al and a cap layer not containing Al are successively grown on a semiconductor substrate and are placed in a halogen gas environment where a chemical reaction between a halogen and an oxide film naturally formed on the cap layer removes the oxide film. Then, without exposing the layer to the atmosphere, the halogen gas environment is replaced with a dry-etching environment and the cap layer is dry-etched to a desired depth. Then, without exposing a semiconductor layer to the atmosphere, the dry-etching environment is replaced with a crystal growth environment. Subsequently, another semiconductor layer is grown on the semiconductor layer. A regrowth interface of excellent cleanliness is realized and the crystallinity of the regrown semiconductor layer is improved.
Patent GB-2334958-B (GB)
Title: Melt flow index determination in polymer process control
Inventor: GEORGE ALAN
IPC: C08F2/00
Filed: 1998-02-25
Granted: 2001-11-07
Abstract: Closed-loop feedback control of (continuous) catalytic polymerisation, by regulating the introduction of a Chain Transfer Agent (CTA) to a reactor, and so polymer chain length formation; through responsive (on-line) MFI determination, of a reactor polymer sample, using an MFI measurement viscometer (70) with dual measurement dies (91, 93), for extended measurement range.
Patent HU-216936-B (HU)
Inventor: FOEHL ARTUR
IPC: F42C19/10
Filed: 1992-03-25
Abstract: A találmány tárgya ütésgyújtó egy hőzzárendelt, egy szerkezeti elemfűratában axiális irányban eltőlhatóan vezetett ütőszeggel (50) egypirőtechnikai, gyűtaccsal (18) ellátőtt gázgenerátőrban, gépjárművekrészére kialakítőtt visszatartó rendszerben, ahől egy gőlyó (22) vagycsap alakjában kiképzett ütésátszármaztató elem a gázgenerátőr házánakvezetőnyílásában a gyűtacs (18) felcsapódási felületével szemben vanelrendezve, és szabad, a gyűtacs (18) felcsapódási felületévelellentétes végével a vezetőnyílás tőrkőlati síkjából kinyúlik és azelőnyösen ütőszegként (50) kiképzett ütőelemmel szemben fekvően vanelrendezve, amelynek az ütésátszármaztató elem (22) szabad végévelszemben fekvő felülete lényegesen nagyőbb, mint ezen szabad végkeresztmetszeti felülete, tővábbá a gázgenerátőr (36) és az ütőszeg(50) két, a vezetőnyílás tőrkőlati síkja mentén elválasztőtt, egybiztőnságiöv-rendszer visszafeszítő berendezésének két szerkezetiegységében (30, 32) vannak elrendezve. ŕ
Patent HU-215843-B (HU)
Title: Process for producing 2-cyano-3-hydroxyenamides and pharmaceutical compositions comprising such compounds as active ingredient
Inventor: BARTLETT ROBERT R
IPC: C07C255/26
Filed: 1993-01-07
Abstract: The Application relates to the products 
<IMAGE>
 in which: 
 
  - R1 represents 
<IMAGE>
 R13, R14 or R15 represent H, halogen or (C1-3)alkyl and n = 1, 2 or 3, 
  - R2 represents H or (C1-3)alkyl, 
  - R3, R4, R5, R6 and R7 represent H, halogen, NO2, CN, (C1-6 )alkyl, CO-(C2-6)alkyl, (C3-6)cycloalkyl, (C1-6)alkoxy or -alkylthio or -(CH2)m-CF3, -O-(CH2)m-CF3, -S-(CH2)m-CF3 , or a -CF2-Hal, -OCF2-Hal, 
<IMAGE>
 
<IMAGE>
 or 
<IMAGE>
 radical with R8, R9, R10, R11 and R12 having the values shown for R3, R 4, R5, R6 and R7, or form -O-CH2-O, 
 to their tautomeric forms and to their salts, as well as to a process for their preparation, to their application as medicaments, especially anti-inflammatories, and to the pharmaceutical compositions which contain them.
Patent HU-214713-B (HU)
Inventor: STRAUBINGER WERNER
IPC: B41F9/10
Filed: 1993-12-15
Abstract: A találmány tárgya rákelszerkezet rőtációs mélynyőmógéphez, amelyfőrmahengerről (1) fölösleges festéket leszedő és a főrmahenger (1)főrgástengelyével párhűzamősan elrendezett rákelt tartal az, amelyheza rákelt a főrmahenger (1) palástfelületének nyőmó rákeltartó vantársítva. A rákel hajlékőny és hősszirányára nézve keresztirányútengely körül fel- és letekercselhető rákelszalagként ( 0) vankialakítva, amely a rákeltartóban (25) annak hősszirányábanelcsúsztathatóan van ágyazva és megvezetve, tővábbá a rákelszalag (20)hősszúsága lényegesen nagyőbb, mint a főrmahenger (1) tengely rányúhősszúsága, tővábbá a főrmahenger (1) tengelyirányban vetthőmlőkőldali végeinél a rákelszalagőt (20) fel- és lecsévélő csévélőszerkezetek (28, 29) vannak elrendezve, amelyekhez a rákelszalagő (20)nyőmtatás közben hősszirányban elcsúsztató és az egyikcsévélőszerkezetről (28, 29) letekercselő és a másikcsévélőszerkezetre (29, 28) feltekercselő hajtószerkezet kapcsőlódik. ŕ
Patent HU-219013-B (HU)
Title: Method and apparatus for the production of mineral wool
Inventor: BATTIGELLI JEAN
IPC: B28B1/00
Filed: 1992-08-20
Abstract: Mineral material, particularly of the basalt type, is fiberized by internal centrifuging in a spinner (1') having a peripheral wall (19) with a multiplicity of orifices through which the melt may emanate into the environment where a hot gas blast attenuates the melt cones emanating from the orifices to fibers. As such mineral material has a high melting point or liquidus temperature, and low viscosity at the liquidus temperature, a high proportion of unfiberized particles is likely to be produced. However, the production of mineral wool with good fiber fineness and largely free of unfiberized particles surprisingly is possible if the cone lengths and the configuration of the gas flows generated around the spinner are such that the majority of the filament forming cones emanating from the spinner orifices intersect the isotherm corresponding to a viscosity of 100 poises, or otherwise reach into a zone cooled down to a temperature corresponding to a viscosity of more than 100 poises. In practice, such a configuration of the gas flows is produced by an outer annular blower (24) complementing the external annular burner (13) which produces jets of cool air so as to bring low-temperature isotherms in close vicinity of the peripheral wall (19) of the spinner (1') where the tips of the cones reach into such cool zone so as to increase the viscosity at the tip of the cones to avoid breakage of the filament to be attenuated.
Patent HU-215651-B (HU)
Inventor: HADI GEZA
IPC: A01H5/10
Filed: 1994-06-17
Abstract: A találmány szerinti kűkőricavőnal kőrai virágzású és érésű,  alacsőnynövekedésű, generatív típűsú, levelei közbenső állásúak a cső  felett,a kalászkapelyvák, a pőrtőkők és a bibeszálak  gyen  én  antőciánősak,csűtkája antőciánmentes, szemtípűsa  sima  szemű,  a  szemek  őpálősancsillőgó sárgás-narancs színűek, a  csövek  alakja  hengeres-kúpős,  acímerfőtengely mind a legalsó, mind a legfelső ől alág fölött rövid. ŕ
Patent HU-217161-B (HU)
Inventor: BORMANN JUERGEN
IPC: D06F37/30
Filed: 1994-09-02
Abstract: A találmány tárgya kőmműtátőrős mőtőr, különösen főrdűlatszám-szabályőzőtt, egyfázisú, sőrős gerjesztésű mőtőr mősóaűtőmatákhajtásáhőz. Aűtőmatizáltan előállítható, és az üzemi, illetvecsatlakőzási feltételek tekintetében könnyen illeszthető kőmműtátőrősmőtőrhőz. A kőmműtátőrős mőtőr csapágypajzsőt (L), tengelyiránybankívül a csapágypajzsnak az állórész- lemezcsőmagőn (P) valófelfekvésével szemben lépcsőzetesen elhelyezett, tengelyiránybankinyúló csapágypajzs-csapágynyakkal (LH) és egy, a csapágypajzs-csapágynyakat (LH) legalább részben magában főglaló, acsapágypajzslépcsőnél (L4) a csapágypajzs-csapágynyakhőz (LH) valóátmenetben tengelyirányban kívül rögzíthető hőrdőzólapőt tartalmaz ahőrdőzólap tengelyirányú hőzzávezetése esetén a csapágypajzs-csapágynyak (LH), illetve a csapágypajzs (L) nyílásain (L3)átbújtatható kefékkel a kőmműtátőrral (KL) való érintkezéshez,valamint egy szerelőcsövet az állórésztekerccsel (W1) valóérintkeztetéshez. ŕ
Patent HU-221468-B (HU)
Inventor: BENEVOLENSKY OLEG
IPC: B21J5/00
Filed: 1998-11-09
Abstract: A találmány eljárás műanyag kompozit tartórúdból és hozzáillesztettfém végdarabból álló kötés, előnyösen kompozit villamos szigetelőteherviselő elem előállítására, amelynek során a tartórúd végérefémperselyt tartalmazó végdarabot illesztünk sajtolással. Az eljáráslényege, hogy a tartórúd végét behelyezzük a perselybe úgy, hogyközöttük rést hagyunk, majd a perselyre kifejtett nyomással asajtolást úgy végezzük, hogy közben folyamatosan mérjük és analizáljuka sajtolás során kifejtett nyomást, a szerszám elmozdulását, a mértértékek alapján meghatározzuk az érintkezési helyzetet, a mértadatokat extrapoláljuk arra a szakaszra, amikor a persely maradóalakváltozást szenved, de a tartórúd még nem károsodik, és az előremegadott optimális összenyomhatósági paraméterekkel rendelkezőillesztésnél a sajtolást leállítjuk. A találmány tárgya továbbáberendezés a találmány szerinti eljárás foganatosítására, amelyberendezés önmagában ismert, célszerűen kompozit szigetelőkhözalkalmazott sajtolóberendezést tartalmaz, amelynek nyomófejekkelellátott sajtolószerszáma és a szerszámhoz csatlakoztatottvezérlőberendezése van. A berendezés lényege, hogy a szerszámhoz (6)egy, a nyomófejek (5) elmozdulását mérő elmozdulásmérő (7) vancsatlakoztatva, az elmozdulásmérő (7) kimenete célszerűen A/Dátalakítón (10) keresztül egy szabályozó- és jelfeldolgozó berendezés(12) egyik bemenetére van elvezetve, a szerszámhoz (6) van még egy, anyomófejre kifejtett terhelőerőt mérő nyomásmérő (8) csatlakoztatva, anyomásmérő (8) kimenete célszerűen szintén A/D átalakítón (10)keresztül van a szabályozó- és jelfeldolgozó berendezés (12) másikbemenetére elvezetve, a szabályozó- és jelfeldolgozó berendezés (12) amért adatok valós idejű analízisét, valamint a kompozit szigetelőszempontjából opti- mális időpontban végrehajtott „állj”-jeletlétrehozóan van kiképezve, és a szabályozó- és jelfeldolgozóberendezés (12) kimenete egy, célszerűen D/A átalakítón (11) keresztülvan egy, az „állj”-jelet létrehozó hidraulikus tápegység bemenetére(9) elvezetve, amelynek kimenete van azután a nyomásérzékelőn (8)keresztül a szerszám (6) mozgatómechanizmusához csatlakoztatva. Atalálmány tárgya még a találmány szerinti eljárással és berendezésselkészült műanyag kompozit szigetelő és hozzáillesztett fém végdarabbólálló kötés. ŕ
Patent IT-1034483-B (IT)
Title: Calcining powder materials, esp. cement - using pre-calcining cyclone prior to rotary drum furnace
IPC: C04B/
Filed: 1975-03-21
Granted: 1979-09-10
Abstract: At least partial calcining of a preheated powder contg. lime occurs before the powder travels through an inclined rotating furnace for further heat treatment, by mixing the hot, partly calcined powder with a liq. or solid fuel in the upper end of the furnace so that a combustible gas is liberated which travels to a calcining chamber together with the exhaust gas from the furnace; in the calcining chamber, the preheated, uncalcined powder is suspended in the gas mixt. and an inlet for a gas contg. O2 is provided so the combustible gas is ignited and the required degree of calcining obtd.; the powder then travels to the furnace. The pref. device includes cyclone preheaters, calcining chamber, furnace and cooler. Esp. for mfr. of cement clinker. High thermal efficiency is achieved.
Patent IT-1239041-B (IT)
Title: Filling element for liquids
Inventor: RADEMACHER FRIEDRICH
IPC: B67C3/26
Filed: 1988-10-27
Granted: 1993-09-20
Abstract: The filling element has a valve support in which there is a centrer to seal the holder mouth, valve mounting surface and body and a syphon in the valve region. The syphon recess (35) on the front of the valve body facing the filling machine tank is an inserted fitting, and the outer limit (40) of the recess is built from the upright body of the valve. The valve seat is above the lower edge of the locking bell (38).
Patent IT-1037474-B (IT)
Title: Printing unit for sheet stack cut edges - transfers image using offset process and an intermediary silicon saturated paper carrier
IPC: B41M/
Filed: 1975-04-21
Granted: 1979-11-10
Abstract: The printed image is brought to the intermediatery carrier using offset printing ink according to the photo-gravure process. A screen with 150 lines/cm. is used. The image is transferred using a silicon-satd. paper and UV-radiation drying. The paper in the stack is aligned using a vibratory jogger. The compelte unit comprises this alignment system, conveyor rails, a processing track with two hydraulic presses, a glue delivery station and a paper stack holder frame. The hydraulic press has a cylinder which operates a pressure plate and a heater plate whereby the stack holder frame is brought into contact with the plate by the pressure plate.
Patent IT-1074334-B (IT)
Title: Unsaturated terpene ketone prepn. from substd. propargyl alcohols - by thermal rearrangement and pref. isomerisation
IPC: C07C/
Filed: 1977-05-17
Granted: 1985-04-20
Abstract: Prepn. of unsatd. terpene ketones comprises rearrangement of the structurally isomeric substd. propargyl alcohols. The unsatd. ketones have formula H-(CH1-CR1Z1-CR2X2-CH2)-n CHX3-CMeZ2-CHX4-CH=CH-CMeO (I) (X1 and X2 each is H or one of X1 and X2 is H while the other forms a bond with Z1. Z1 together with X1 or X2 is a bond or, separately, is H, OH or lower alkoxy. n is 1 or 2. When n= 2, X1, X2, Z, R1 and R2 are opt. different. X3 and X4 are such that one of substituents is H, while the other, together with Z2, ia a bond. (I) are prepd. by heating propargyl alcohols having formula: H-(CHX1-CR1Z1-CH2X2-CH2)-n CH-(MEOH-C XI CH)-CMe=CH2 (II) to 100-400 degrees C. Reaction can take place in the liquid or gas phase. (I) may be used as perfumes and as intermediates for prepn. of other perfumes, e.g. ionone and irone; pharmaceuticals, agricultural chemicals and dyes. Typically a substd. propargyl alcohol CH2X1-CHMeZ1-CR2X2-CH2-CH-(-MEOH-C XI CH)-CMe=CH2 is used for prepn. of ionone or irone.
Patent IT-1124865-B (IT)
Title: Brake pressure control valve for motorcycle
Inventor: BERISCH VOLKER
IPC: B60T/
Filed: 1979-10-31
Granted: 1986-05-14
Abstract: A brake pressure control valve is for a motorcycle, in which a footbrake operates the front and rear brakes and a handbrake lever operates the front brake. The pressure control valve has a stepped piston (8) with the larger face subjected to the foot pedal brake pressure and the smaller face subjected to the rear brake pressure. The piston is coupled to a second piston (9) whose input face is subjected to the handbrake pressure. The second piston has an input face area size between the area sizes of the faces of the stepped piston. Thus the rear brake line is prevented from being vented too rapidly causing cavitation and ingress of air.