Abstract: A portable frame adapted to be mounted on a beach adjacent a lake. The portable frame has a reversible motor and a pair of drive wheels driven by the motor. A rake is provided with an elongated handle. The drive wheels of the frame are adapted to engage the handle of the rake to move the rake backward and forward powered by the motor. The rake has teeth which fold inward when the rake is moved forward into the lake along the lake floor powered by the motor and the teeth will remain upright when the rake is powered back out of the lake, so that the teeth will engage the weeds and will take or pull the weeds out of the bottom of the lake as the rake is powered back out of the lake.

Abstract: A rotary filament attachment to replace the rigid steel cutter blade on a conventional grass edger device, the attachment comprising a pair of disc members, having central openings and opposed inwardly directed peripheral flange portions or projections to define an annular cavity therebetween for storage of a filament line supply when the discs are installed through the central openings on the drive spindle of the edger. A plurality of locking catches or holes are provided in the disc flanges or projections for extension therethrough of end cutting lengths of filament from the respective end portions of the filament line supply when the discs are bolted on the drive spindle.

Abstract: A corn saver apparatus removably attached to a self-propelled commercially available corn harvester which facilitates harvesting of corn growing in a field. The apparatus comprises an agricultural implement which augments a standard corn harvester by picking up stalks of corn which have fallen, and further by moving broken stalks of corn into the harvesting apparatus. The apparatus of the present invention is removably mounted in overlying relationship respective to the gathering apparatus of a conventional corn harvester and significantly increases the yield realized from a field of corn by avoiding the waste of corn which heretofore has been left lying on the ground.

Abstract: A crop harvesting machine has a crop harvesting header, a mobile frame and improved header suspension and lift means. The frame is adapted to move across a field in a forward direction and includes upper frame structure extending transversely to the forward direction and a lower wheel frame assembly. The assembly includes a transverse cylindrical member being rotatably mounted to and supporting the upper frame structure. Lift means is provided, being actuatable for moving the lower assembly, and thereby rotating the cylindrical member thereof, relative to the upper frame structure to effectuate raising of the upper frame structure and the cylindrical member relative to the field. The improved header suspension and lift means includes upper means pivotally interconnecting an upper portion of the header with the upper frame structure and lower elongated means pivotally interconnecting a lower portion of the header with the cylindrical member of the wheel frame assembly.

Abstract: A baler adapted to be pulled along the ground to pick up a windrow of hay and roll the hay into a cylindrical bale of substantial size and weight. The bale is formed in a zone defined between a lower belt conveyor and a plurality of endless belts disposed in transversely spaced relation above the lower belt. The upper belts are disposed to encompass a substantial portion of the periphery of the bale being formed to compress the same to the desired density. A bale tightener assembly is pivotally mounted on the baler and includes rollers in engagement with the upper belts. The tightener assembly is biased against the belts by tension springs arranged and functional in a novel manner.

Abstract: Disclosed is a method and apparatus for winding covered yarn, namely non-elastic yarn twisted about a strand of elastomeric yarn, on a core to form a take-up package so that the wound covered yarn can be drawn (unwound) from the package without hanging up on itself or puckering.

Abstract: Open-end spinning machine apparatus is provided which includes a yarn measuring device at each of the individual spinning units for determining the transverse dimension of the running yarn produced at the spinning units. In addition, intermediate storage means are provided for electronically storing yarn measurement data at each of the individual spinning units. In order to process the yarn measurement data, a process computer is provided at a mobile servicing instrument which is selectively movable to respective servicing positions at the spinning units. The process computer and mobile servicing instrument also includes means for carrying out servicing operations at the respective spinning units in the event of detected yarn flaws or the like.

Abstract: In a textile yarn processing machine, such as a two-for-one twister or the like, there is provided a plurality of yarn processing stations each including a spindle assembly carrying a supply package of yarn to be processed and a take-up assembly for forming a take-up package of yarn after processing. A yarn knotter mechanism is selectively positioned in front of the yarn processing stations in the event of yarn breakage for knotting the ends of the broken yarn extending respectively from the spindle assembly and the take-up assembly. Improved yarn transfer mechanisms are provided for withdrawing the broken end of yarn from the take-up assembly and positioning the yarn in the knotter mechanism for being knotted with the broken end of yarn from the spindle assembly.

Abstract: The doffing of full bobbins built on spools placed on the vertical spindles of fly-frames equipped with revolving flyers is performed by combining gripping means such as resilient clips carried by each flyer with retaining means such as an annular groove formed at the upper end of each spool. The releasable axial coupling thus provided is capable of temporarily supporting a spool and full bobbin in the top position while the spindle is moved downwards in order to remove the spool.

Abstract: The double torsion twisting mechanism includes a rotatable spindle which rotatably supports a bobbin. A coupling unit connected to the bobbin has its axis offset to the bobbin axis to prevent rotation of the bobbin. A yarn ballooning plate is secured to the spindle and rotates the coupling unit via a flexible membrane connected between the plate and the coupling unit. The flexible membrane is cut-out in the region of a radial yarn guide channel which rotates with the spindle.

Abstract: A timer device wherein a timer cam disk to be moved from a non-operating position to an operating position at a preset time point in cooperation with a timer setting drum is so formed as to be returned to the non-operating position from the operating position at a comparatively higher speed only during a predetermined time period after it is moved from the non-operating position to the operating position in order to prevent the time during which the timer cam disk is maintained in the operating position from becoming unnecessarily long.

Abstract: A coupling shackle for field/factory assembly of lengths of chain, rope, cables, or the like/or attachments thereto; said coupling shackle comprising a generally U-shaped unit comprising an overlay/underlay assembly of two or more relatively nested complemental-configured U-shaped members which are traversed and interconnected at their leg ends as by means of a bolt or pin or the like. Said members may be first stamped or otherwise cut out of sheet/plate stock and then bent into U-shaped configurations; the bowed intermediate portions thereof being subsequently U-shape sectionally formed. The open end leg portions at opposite sides of the unit are apertured and side-by-side mounted upon the structurally cooperating interconnecting bolt or pin.

Abstract: A gas turbine engine having a compressor and an air-cooled turbine is provided with a cooling system for decreasing the temperature of the turbine cooling air. A compact heat exchanger, rotatable with the compressor, receives a portion of the pressurized air which is bled from the compressor. Relatively cool engine lubrication oil is pumped through the heat exchanger into heat exchange relationship with the pressurized air, thereby cooling the air and heating the lubrication oil. The cooled air is then routed to and circulated through the turbine blades to provide improved internal cooling thereof. The heated lubrication oil is collected from the heat exchanger and routed to a second heat exchanger wherein it is placed in heat exchange relationship with engine fuel to recover the heat extracted from the compressor bleed air and to return the heat to the engine operating cycle. The cooling system is designed to contain the lubricant in the unlikely event of a leak developing in the heat exchanger.

Abstract: An engine having a first reaction chamber to which fuel is to be supplied, either alone or with another reactant, and to which heat is applied to effect an endothermic chemical reaction to produce, under substantially reversible conditions, a reformed fuel, a second reaction chamber to which the reformed fuel discharged from the first reaction chamber is passed together with air or other reactant to effect an exothermic chemical reaction in the second reaction chamber, and a heat exchanger (conveniently of the fluidized bed type) to transfer heat produced by the exothermic reaction in the second reaction chamber to the first reaction chamber to effect the endothermic reaction.

Abstract: An integrated control system for use with a gas turbine engine is provided wherein the control system includes a fuel control valve adapted to meter the flow of fuel to the engine, variable geometry control valve to control compressor variable stators or bleed, back-up control means for providing signals to the control valves and primary control means for providing bias of the signals. Means are provided for biasing the signals during normal mode of operation and the means may be ineffective to bias the signals during failed mode of operation.

Abstract: A jet propulsion engine and a method of operating a jet propulsion engine for propulsion of an aircraft over a wide range of speed from zero to supersonic. The engine is a turbofan type with a duct burner and with separate variable exhausts from the duct burner and from the gas turbine engine. The gas turbine core engine includes a gas generator and a low pressure turbine which drives the fan. The fan includes variable outlet guide vanes and the low pressure turbine includes a variable first-stage nozzle. The engine is operated as a normal duct burning by-pass jet engine from zero air speed up to about Mach 3. The fuel to the core engine is shut off through a transition range of speeds. Above this range the engine operates with only the duct burner supplied with fuel, with the gas generator windmilling, and with the low pressure turbine continuing to drive the fan to supercharge the duct burner, which operates as a supercharged ramjet.

Abstract: Axial flow turbomachinery having an impeller with a plurality of contoured blades mounted within a diffuser throat and about a central rotatable hub. This blade shape is defined by the ratio of the blade root and tip chords to the minimum midsection blade chord, which is between about 1.25 and about 2.25. The ratio of blade pitch at the root and tip sections as compared with the blade midsection pitch is preferably between about 1.0 and about 1.4.This configuration of a preferred diffuser is described by the following relationship: ##EQU1## Where A.sub.t is the diffuser cross-sectional area at the diffuser throat, A.sub.o is the diffuser cross-sectional area at the outlet, 1 is the diffuser length from the diffuser throat to the diffuser outlet, x is a distance along the diffuser measured from the diffuser throat toward the diffuser outlet, A.sub.x is the diffuser cross-sectional area x distance from the diffuser throat and n is a value between about 2 and about 4.

Abstract: Sensed engine inlet temperature is utilized to detect compressor surge whenever its computed temperature rate of change or rise signal exceeds a predetermined value. This signal may be coupled to another engine operating parameter, such as rotor speed, compressor discharge pressure and the like and permutations thereof, to guard against false detection. Engine inlet temperature rate of change or rise is an efficacious surge detection parameter particularly when an afterburner is used inasmuch as the hot gases of the afterburner will have a significant influence on the engine inlet temperature sensor in a reverse flow situation making that signal a positive indication of imminent surge.

Abstract: A gas turbine engine comprises a duct for the passage of a thrust producing gas, the duct having an upstream portion and a downstream portion spaced apart in a direction parallel to the axis of the duct, the downstream portion being movable relatively to the upstream portion between a closer spaced position and a further spaced position. A plurality of thrust reversal doors are pivotally connected to an upstream end of the downstream portion and extend therefrom towards the upstream portion, and a linkage assembly has a one end fixed relatively to the upstream portion and acts on each thrust reversal door.

Abstract: Fluidic combustion control of a ramjet by injecting a fluid into the base recirculation region to reduce the critical injection parameter, or to shut down the ramjet without affecting the hot air flow.

Abstract: An internal combustion engine having an exhaust system provided with exhaust gas purifying means and secondary air supplying means disposed upstream thereof includes a secondary air injection compensating system comprising vacuum introducing means adapted to introduce and reserve the vacuum from an intake manifold vacuum port; secondary air switching means including two diaphragm means and a valve mechanism linked therewith; information processing means adapted to process the information from and O.sub.2 sensor and an acceleration detector to make a selection therefrom and issue a command; and vacuum switching means including two vacuum switching valves for selective conduction of said vacuum to said secondary air switching means by said command, and a compensating switching valve.

Abstract: An internal combustion engine having an exhaust system provided with exhaust gas purifying means and secondary air supplying means disposed upstream thereof includes a secondary air supply control system comprising vacuum introducing means adapted to introduce and reserve the vacuum from an intake manifold vacuum port; secondary air switching means including two diaphragm means and a valve mechanism linked therewith; information processing means adapted to process the information from an O.sub.2 sensor and an acceleration detector and issue selective commands; and vacuum switching means including two vacuum switching valves to be controlled by the command associated with the O.sub.

Abstract: A fog smoke-filtrating and muffling device utilized by vehicle is an apparatus utilizing an intake pipe to lead the waste gas of engine to blow the water, which is contained in a tank, to disperse to become a fog. The carbides and impurities in the waste gas can be dissolved in the water. Then, in a evaporation chamber and a releasing chamber, the water droplets and waste gas can be separated from each other, and the purified waste gas is exhausted. The water droplets can be collected and filtrated through a reservoir. The water in the reservoir can be used again. Meanwhile, the water in the tank of this invention can absorb the noise and the shock of engine. The cyclic flow of water in this invention can cool the engine as well.

Abstract: A load responsive fluid power control system using servo type flow control valves and fluid motors supplied by a variable displacement pump. The pump displacement is regulated by a control valve in response to the motor load pressure to vary the pump displacement to maintain a constant preselectable ratio between the pump outlet pressure and motor load pressure and to vary the pressure differential between pump outlet pressure and motor load pressure with variation in magnitude of the load. The pump control also limits maximum and minimum system pressures.

Abstract: A hydrostatic transmission having an inclined-disk variable-displacement pump and a drive-flange hydrostatic motor on a common support which includes a body having a cylindrically concave surface turned toward the motor. Between the motor drum and the surface, there is provided an intermediate disk having a convex cylindrical surface adapted to ride upon the concave surface. Means is provided in the body for displacing the drum of the motor about a pivot axis which coincides with the axis of curvature of the two surfaces. The motor and pump are both axial-piston machines.

Abstract: A housing includes therein a servo pressure control valve disposed in parallel to a master-cylinder piston. The foot pedal operates an actuating member which operates directly on the master-cylinder piston and via a forked section of the actuating member on the servo pressure control valve.

Abstract: In order to prevent scale formation in a hot dry rock geothermal system, a mixture of acetone and water is utilized as the working fluid. Such fluid reduces the amount of scale formation generally associated with such system.

Abstract: In order to extract energy in a matter more efficient than is presently known to the art, from hot dry rock geothermal systems, a mixture of water and calcium chloride is used. The fluid mixture is injected into a formation and forced through the formation with simultaneous extraction of heat from the energy recovery or heat extraction surrounding rocks. The fluid and a larger fraction of its contained energy are then recovered than can presently be recovered by technology known to the art.

Abstract: Two gas turbine helicopter engines are coupled together for isochronous operation to supply a common load. A control circuit assures that the power delivered to the common load is equally divided between the two engines. The torque of each engine is detected and the torques are compared to established control signals for the engines.

Abstract: The invention relates to an above sea-level platform, for use as, for example, an oil-rig, which is connected to a sea-bed foundation by a ball-joint arrangement. For protection, the ball joint is hollow and partially received in a recess at the lower end of a tubular extension of the platform through which an oil conduit leads from the foundation via the hollow ball joint, the two parts of which are held in sealing abutment by a draw member.

Abstract: Material is cooled by direct contact with CO.sub.2, and the CO.sub.2 vapor is recovered. A coolant reservoir is created in a holding tank wherein CO.sub.2 vapor, CO.sub.2 liquid and solid CO.sub.2 exist in equilibrium in the form of slush plus vapor. Liquid CO.sub.2 is supplied to a cooling chamber to cool the material by direct contact, creating contaminated CO.sub.2 vapor. The contaminated CO.sub.2 vapor is removed and directed to the coolant reservoir to condense the CO.sub.2 vapor and any contaminants which liquefy at temperatures above -69.degree. F. by melting solid CO.sub.2. Clean CO.sub.2 vapor and any noncondensables are withdrawn from the holding tank and the withdrawn CO.sub.2 vapor is reliquefied and returned to the CO.sub.2 storage vessel. Condensable contaminants are periodically removed from the holding tank by heating to a temperature where they can be blown out the bottom.

Abstract: An apparatus for the automatic production of ice from water filled stalls and comprised of means applying heat absorption thereto until an iced condition is reached, followed by the simultaneous application of heat thereto to thaw the stall-to-ice interfaces and of refill water thereto to eject the ice by means of floatation; and comprised of one or a series of stalls embraced by the evaporator of a refrigeration system having a hot gas bypass that is intermittently discharged through the evaporator simultaneously with refill water applied to the stall or stalls to eject the ice, a temperature sensor and refrigerant control alternately reacting to effect the iced and thaw conditions of the stall, thereby automatically cycling the apparatus for continued operation.

Abstract: A control means is provided in the control circuit for a heat pump whereby a change in mode of the heat pump will result in the compressor being deenergized and maintained deenergized for a period of time determined by the control means, to allow equalization of refrigerant pressure within the heat pump system.

Abstract: A capacity control system of compressor for heat-pump refrigeration unit including a bypass adapted to communicate the suction side of the compressor with a bypass port opened to a cylinder chamber of the compressor, and a valve mounted adjacent the bypass port for opening and closing the bypass. The valve is subject at the back thereof to the pressure of a refrigerant in a refrigerant passage which becomes a low pressure area in a cooling mode operation of the refrigeration unit and becomes a high pressure area in a heating mode operation of the unit, and the valve is caused to be automatically opened or closed by the change in the pressure, so that the performance of the compressor can be automatically controlled in such a manner that its capability is reduced in the cooling mode operation and increased in the heating mode operation.

Abstract: In an absorption refrigeration system of the kind having an inert, non-condensible pressure-equalizing gas the flow of the gas is controlled by providing a flow restriction in the connection which conveys the stream of inert gas from the absorber to the inlet end of a refrigerant liquid precooler. The flow restriction also diverts part of the gas flow into the low-temperature evaporator.

Abstract: A closed cam track, characterized by curves corresponding essentially to the formula Y = f(X.sup.n) where Y is the axial displacement of needles in grooves of the track, X is the peripheral rotational displacement of the track at constant angular velocity and n is greater than or equal to 3, is provided for a circular knitting machine.

Abstract: A pattern contained in an information carrier is transferred to and stored in a pattern drum provided with feeler levers, a retaining guide, and a switch. Upon the movement of the lock over the needle bed, this pattern is then transferred to pushing rod jacks which in turn act upon the needles. The pattern can be suspended for a predetermined distance during an interruption phase while the pattern information itself is retained in the pattern drum, and rapid and reliable operation of the knitting machine is ensured by the use of resilient or articulated feeler levers having nose-like projections at their outer ends. To ensure proper guidance of the feeler levers, the retaining guide includes a needle-shaped portion extending into the vicinity of the switch.

Abstract: A needle support assembly including a needle support member, such as a needle bar, a row of knitting needles arranged against the support member, and a spacer between each two successive needles. The spacers are independent of the needles and support member, and are of precisely equal thicknesses, so that each two successive needles in the row are spaced apart the same predetermined distance. As a result, the usual series of parallel slots in the needle bar, or other support member for the needles, can be eliminated. The needle support member may have a groove for accommodating a butt projecting laterally from each needle and spacer, or the support member may have a ridge or ridges over which a notch or notches in each needle and spacer fits. Thin plates extend across the groove or ridges at regularly spaced apart locations, and a predetermined number of needles and spacers fit between each two plates, the spacers abutting the plates being slightly thinner than the other spacers.

Abstract: A thread supply device for a textile machine, such as a knitting machine, having a drive. The thread supply device includes a thread drum on which a thread issuing from a supply bobbin can be wound tangentially to form an intermediate thread supply and from which the thread can be removed over a removal edge of the drum. A thread-control element is positioned adjacent to the path of thread removal in the vicinity of the removal edge, and against which the thread abuts laterally due to the tension of removal during a positive thread supply mode. The thread-control element also functions as a thread tension-sensing element and is movable responsive to a decrease in the tension of the removed thread such that, when this tension falls below a predetermined value, this element activates a switching structure which stops the machine drive.

Abstract: Pneumatic yarn feed and yarn change mechanism has a plurality of yarn feed paths and a plurality of control elements for controlling passage of yarn for each of these paths independently. Flow of fluid through selected yarn feed passage when the control element is in a feed position propels leading end of yarn to knitting needles. Movement of control element out of feed position to trap position causes yarn to be severed and trapped and held in readiness for subsequent selection.In a preferred embodiment side by side control plates are moved pneumatically by pistons arranged one above the other.

Abstract: A slide-fastener stringer half comprises a knit tape having a plurality of parallel longitudinally extending wales and a plurality of transversely extending courses, and a monofilamentary coupling element on the tape and having a succession of turns each having a pair of shanks and a coupling head joining the shanks and projecting transversely beyond the longitudinal edge of the tape. The shanks of each turn lie at least in regions adjacent the respective head in a plane generally perpendicular to the tape. The tape comprises at least one warp yarn forming a chain knitted into the tape at every other course and overlying the shanks at the regions adjacent the heads. Thus the shanks are laid into the chains at these regions so that the coupling element is thoroughly integrated into the knit of the tape. The tape itself may be formed of a full-tricot ground. Alternatively the tape can be formed of second weft yarns having open loops at each course and extending transversely each over two respective wales.

Abstract: There are provided jacquard controlled warp knitting machines equipped with yarn guide units having yarn guides wherein the heads of said yarn guide members are so oriented that, when uninfluenced by the jacquard dropper pins, two or more yarn guide member heads may pass between any predetermined pair of needles on the needle bar of the machine.

Abstract: A domestic clothes washer has an outer imperforate water container to retain the washing fluid and an inner perforate spin tub which is rotatable to centrifuge the washing fluid from clothes being washed therein. A vertically reciprocating agitator in the inner spin tub provides a pulsating toroidal circulation of washing fluid. The spin tub has a perforate generally vertical side wall and an imperforate bottom wall joined thereto by a curved wall portion containing a circumscribing row of holes positioned thereon located so as to carry particulate matter from the spin tub during wash periods while minimizing undesirable back flow through the row of holes during spin periods of the tub.

Abstract: An agitator for a vertical axis automatic clothes washing machine has an upper, auger portion which is rotatable in one direction about the vertical axis. A lower portion of the agitator oscillates in two directions. The lower portion has a skirt and carries radially-extending vanes on an upper surface thereof. A plurality of crescent-shaped, lobe-like lifting cams project outwardly and upwardly from a periphery of the skirt. Fabric articles contacted by the cam surfaces as the lower portion of the agitator oscillates to and fro during clothes washing are continuously lifted at the lower, outer portion of the wash basket and urged along a desired toroidal rollover path. The effective, high density washing action provided permits use of less hot water, rinse water, and detergent than in previously known agitation devices, and allows use of a small machine container for normal wash loads.

Abstract: An agitator for a vertical-axis automatic clothes washing machine has a plurality of circumferentially spaced apart vanes extending upwardly from a skirt adapted to overlie the bottom wall of a tub or receptacle. A corresponding plurality of lobe-like cams projects outwardly and upwardly from at or near the periphery of the skirt in the alternate spaces between the vanes. Each cam extends approximately 5 to 15.degree. upwardly from the horizontal and is geometrically defined by two edges forming a segment of the surface of a cone co-axial with the agitator. The inner edge of each cam has the radius of the circular perimeter of the agitator skirt with which the edge is co-linear; the upper edge either has a somewhat smaller radius in a crescent-shaped configuration or has an irregular, double-lobe configuration.

Abstract: A time lock usable with a lock mechanism having a bolt displaceable along a path for opening a door has a housing which is fixed adjacent the path and in which a keeper is vertically displaceable between an uppermost blocking position, a lowermost unblocking position, and an intermediate position. A clockwork in the housing displaces a lock slide horizontally from a holding position wherein a recess in this lock slide is out of alignment with a dog pivoted in the housing into a freeing position with the recess and dog aligned after elapse of a predetermined interval of time. This locking dog is carried on a locking pawl which is connected via a shortenable link to the vertically displaceable keeper. When the clockwork displaces the lock slide into the freeing position the keeper automatically drops into the intermediate position, with the dog entering upwardly into the recess in the lock slide.

Abstract: A cylinder for a safety lock with a cylinder housing and a cylinder plug has tumblers made in the form of plug pins and housing pins. The tumblers are aligned by a key inserted into the lock. Each row of the housing pins is mounted with an associated pin spring in a respective separate chamber, the chambers being installed in respective recesses in the cylinder housing. The separate chambers are made in the form of sliders insertable in the axial direction in longitudinal channels in the cylinder housing, housing pins with their spring being guided in bores. The sliders are mounted so that they have axial play in the longitudinal channels.

Abstract: A mount for several keys is secured in a convenient place to support the keys in a row dependent from tags that identify the keys. A support strip long enough to mount all the keys has the hook part of a two-part hook-and-loop pile fastener on a front face and a pressure-sensitive adhesive layer on a rear face, with a manually removable release sheet covering the adhesive layer. The key tags are each cut from resin material joined to the loop part of the two-part hook-and-loop fastener so that the loop part is arranged on a rear face of each of the key tags, and the front faces of the key tags have a front surface suitable for indicia to identify the keys. Each of the key tags has a die-cut hole near an edge and a key ring in the hole to support keys connectable to the rings to be dependent from the tags. The tags are releasably attachable to the support strip to mount the keys in a way that makes the front surfaces of the tags visible, and the keys are usable while connected to the tags.

Abstract: A method of controlling the shape of a workpiece in a rolling mill through the control of workpiece crown as the workpiece is being rolled includes the calculation of the roll-separating force required on each reducing pass as a function of roll elasticity, diameter and crown and workpiece resistance to deformation, width, entry crown and target crown.

Abstract: The rolling force, rolling torque, incoming workpiece thickness and roll gap at a first rolling stand are detected when a workpiece is fed into the nip between the rolls of the first rolling stand to provide their reference values P.sub.10, G.sub.10, H.sub.10 and S.sub.10 which are stored in a memory, and the reference torque arm l.sub.10 is computed on the basis of the reference values G.sub.10 and P.sub.10 of rolling torque and rolling force. The rolling force, rolling torque, incoming workpiece thickness and roll gap at a second rolling stand are detected when the workpiece is fed into the nip between the rolls of the second rolling stand to provide their reference values P.sub.20, G.sub.20, H.sub.20 and S.sub.20 which are stored in a memory, and the reference torque arm l.sub.20 for the second rolling stand is computed on the basis of the reference values G.sub.20 and P.sub.20 of rolling torque and rolling force. The torque arms l.sub.1 and l.sub.