Abstract: The invention relates to a heavy goods vehicle, specially for the transportation of slag, comprising a loading platform for vessels containing slag, fitted with a gripper device for receiving and moving a standardized load-bearing implement which can be actuated by a hydraulic cylinder (11) and an anti-tilt device (15) for the vehicle which operates during movement of the load-bearing implement. The vehicle is also fitted with at least one hydraulic cylinder (11) with switches. Upon a given stroke of the piston, at least one switch engages a device detecting hydraulic pressure inside the cylinder on one or both sides of the piston. The pressure detection device triggers a security device, e.g. a display for the driver or an operation blocking device.

Abstract: An audible safety warning message is recorded on a digital sound chip and the chip is installed in an extension tool such as an extension pole, a ladder or the like. The message playback sequence is initiated when the tool is activated to provide the user with a warning to avoid dangers such as overhead power wires and the like.

Abstract: The luffing angle measurement system includes a non-contact distance measuring device mounted on the nose section of a first boom. The non-contact distance measuring device measures either a distance to a second boom pivotally connected to the first boom or measures a time delay between the transmission of electromagnetic energy towards the second boom and reception of electromagnetic energy reflected from the second boom. A controller then converts the measured distance or the measured time delay into a luffing angle.

Abstract: A gantry crane boom protection and anti-collision system employing laser guns aimed outboard from the crane superstructure parallel and below the sides thereof with photodetectors to automatically respond to a reflected signal and slow or stop any lateral movement of the crane.

Abstract: An aerialift warning system and method for use on aerialift equipment to warn the aerialift operator to fasten his/her safety lanyard and to warn persons within the zone of danger below the aerialift boom/basket of the impending danger posed by the descending boom/basket. The system includes a warning module and a speaker. The warning module includes a driver circuit for receiving a boom movement input signal and for asserting an up motion or down motion signal, and a processing circuit for receiving the up motion and down motion signal. The processing circuit contains an execution program to assert one or more warning messages contained in an audio warning circuit. The asserted one or more messages from the audio warning circuit are sent to a speaker.

Abstract: Disclosed is a machinery operator protection system and method, which inhibits the use of machinery unless the operator of the machinery is properly secured with a lanyard and/or body harness to the machinery. The disclosed system includes a lanyard connection detector for detecting proper attachment of at least one lanyard to a machinery operator and a lanyard interlock control for controlling a switch to selectively enable activation of the machinery when the lanyard connection detector indicates that the operator is properly attached to the machinery with the lanyard. The disclosed method includes the steps of: detecting when at least one safety lanyard is properly attached to a between a machinery operator and a piece of machinery; and inhibiting operation of the machinery unless proper operator safety lanyard attachment is detected.

Abstract: A Pole Alarm System including an electromagnetic field sensor and collision sensors for detecting overhead power lines and physical obstructions within the intended path of a telescoping mast or utility boom device is disclosed. The present alarm system includes a mast-mounted housing containing the sensors and a microprocessor-based control unit which interprets the output signals of the sensors and provides both audible and control feedback to a safety control module in the vehicle to alert the operator of impending contact and to automatically stop the movement of the mast. The alarm housing also features a light source which provides illumination in the direction of movement of the mast to assist in positioning thereof. The light source also functions as a heating element to prevent the accumulation of ice on the housing which would detrimentally affect the performance of the system.

Abstract: A device which relates to the monitoring of things such as cranes and hoists and seeks to improve on known so-called capacity limiters or overload devices usually associated with the hoist or chain rope. A monitoring device for use with a crane or hoist having a drive roller with a drive shaft and a gearbox directly or indirectly attached to the drive shaft. The monitoring device includes a means of resisting rotational movement of the gearbox located between the gearbox and an adjacent rigid structure, the means between the gearbox ad the adjacent rigid structure being such as to allow a limited degree of movement of the gearbox, and there being a means to react to the movement of the gearbox associated with the means of resisting rotational movement.

Abstract: An improved crane warning system which includes acceleration sensors, motion sensors, hydraulic sensors, remote communications and/or a camera. The crane warning system may include a crane warning device integrated into the ball of the crane.

Abstract: A Pole Alarm System including an electromagnetic field sensor and collision sensors for detecting overhead power lines and physical obstructions within the intended path of a telescoping mast or utility boom device is disclosed. The present alarm system includes a mast-mounted housing containing the sensors and a microprocessor-based control unit which interprets the output signals of the sensors and provides both audible and. control feedback to a safety control module in the vehicle to alert the operator of impending contact and to automatically stop the movement of the mast. The alarm housing also features a light source which provides illumination in the direction of movement of the mast to assist in positioning thereof. The light source also functions as a heating element to prevent the accumulation of ice on the housing which would detrimentally affect the performance of the system.

Abstract: An alarm device is designed to warn of danger of hitting high voltage overhead power lines by a crane in motion. The alarm device is composed of an electric-field sensor for detecting the alternating electric field of the overhead power lines and for outputting an alternating current, which is then converted or amplified by an amplifier connected with the electric-field sensor. An alternating voltage is outputted by the amplifier such that the alternating voltage is rectified and filtered by a rectifier/filter circuit connected with the amplifier. A direct current voltage output is brought about by the rectifier/filter circuit. A starter is disposed between the rectifier/filter circuit and a wireless transmitter capable of being activated by the starter to transmit a wireless signal at such time when the value of the direct current voltage exceeds a preset value. The alarm device is further composed of a wireless receiver/alarm for receiving the wireless signal and for effecting a warning signal.

Abstract: A Pole Alarm System including an electromagnetic field sensor and collision sensors for detecting overhead power lines and physical obstructions within the intended path of a telescoping mast or utility boom device is disclosed. The present alarm system includes a mast-mounted housing containing the sensors and a microprocessor-based control unit which interprets the output signals of the sensors and provides both audible and control feedback to a safety control module in the vehicle to alert the operator of impending contact and to automatically stop the movement of the mast. The alarm housing also features a light source which provides illumination in the direction of movement of the mast to assist in positioning thereof. The light source also functions as a heating element to prevent the accumulation of ice on the housing which would detrimentally affect the performance of the system.

Abstract: A method and device for damping the oscillation of a load suspended from a rope on a crane is presented. A digital filter accepts an arbitrary velocity input signal and produces a velocity signal output similar to the input and that runs a bridge or trolley drive while damping the load's swing. One version of the damping filter may be implemented by programming a microprocessor to output a simple average of the input signal and the input signal delayed by one-half period of the pendulum motion of the load. A second version of the invention averages the input signals over the period of the pendulum motion to producing a damping signal. A third version of the invention averages the input signal with two delayed versions of the input signal. The third version will produce motion that will dampen load swing for a large range of rope lengths. Furthermore, if an additional signal representing rope length is taken, all three versions can be adapted to dampen swing for a full range of rope lengths.

Abstract: In an overhead hoist transfer having a moving carriage with a hand portion, which holds a load, elevatably suspended therefrom; and a means for teaching an appointed stop position on a placement base, on which said load is placed, to said moving carriage, LEDs 7a and 7b are installed at the hand portion 6, and a position detecting portion 12 consisting of a lens 12a and PSD 12b is installed at the placement base 53 side, in order to automatically and accurately enable a teaching of position correcting data in a short time without use of any manpower.

Abstract: A sensor system for use on drilling equipment to detect the presence of high voltages during horizontal or vertical drilling and providing an alarm signal corresponding to one of three possibilities: (1) the drilling tool hitting a high voltage line; (2) the drilling tool remaining in contact after hitting the high voltage line; and (3) an exposed or damaged high voltage line in close proximity to the drilling implement. The sensor system detects alternating current, converts the alternating current signal to a pseudo square waveform signal, compares the magnitude of the square waveform signal with a reference voltage, and sounds an alarm if the magnitude of the square waveform signal exceeds the reference voltage. The sensor system also incorporates a self-test circuit which allows an operator to check its functionality before use. The operator can also check the sensor at any time during drilling process.

Abstract: A pump failure alarm system which is provided in a hydraulic working machine comprising hydraulic pumps driven by a prime mover, delivery lines joining with one another into one common delivery line on the downstream side, check valves provided in the delivery lines upstream of a point where the delivery lines join with one another, a hydraulic cylinder driven by a hydraulic fluid introduced through the common delivery line, and a hydraulic reservoir. The pump failure alarm system comprises pressure sensors for detecting respective delivery pressures of the hydraulic pumps, bypass lines having one ends connected to the delivery lines at points upstream of the check valves and the other ends connected to the hydraulic reservoir, solenoid switching valves for opening and closing the associated bypass lines, an alarm display unit for giving an alarm in correspondence to each of the hydraulic pumps, and a controller.

Abstract: The present invention relates to a control device for a hoist mechanism of a crane, preferably for a crane with a jib which can be varied in length and be luffed, with a hydraulic motor driving the hoist mechanism drum which motor forms a closed hydraulic circuit together with a hydraulic pump driven by a motor, preferably by a diesel engine, and with a locking brake for the hoist mechanism drum.

Abstract: The protection system for outriggers of a chassis includes a non-contact distance measuring device, associated with at least one of the outriggers and the chassis, mounted on one of the outriggers and the chassis. The non-contact distance measuring device measures the distance to the ground along a predetermined angle, and generates a warning signal based on the measured distance. A controller stops operation of the outriggers in response to the warning signal.

Abstract: A cargo handling path setting method and apparatus determine arbitrary hoisting and lowering speeds of a suspended load and the times required for hoisting and lowering to set hoisting and lowering speed patterns, determine an arbitrary traversing speed of the suspended load and the time required for traversing to set a traversing speed pattern, set the positions and heights of obstacles present around the cargo handling path based on data from stacked load sensors, and further set an arbitrary waiting time for traversing and an arbitrary waiting time for lowering; then conduct a theoretical simulation test based on these set conditions to compute a cargo handling path, and if it is determined that the suspended load passing along the cargo handling path will collide with the obstacles, repeat the procedure of revising the set conditions and conducting a theoretical simulation test again.

Abstract: A sensor for determining the position of a movable object along a selected axis. The system includes a target positioned at a location aligned with the selected axis. An optical energy emitter is mounted on the movable object and has a beam dispersion greater than two degrees directed at the target. An optical energy receiver is mounted on the movable object and aligned to receive optical energy reflected by the target. The optical energy detector generates a receive signal indicating reception of the optical energy. A time of flight circuit coupled to the emitter and receiver generates a flight time signal indicating the elapsed time from emission of the optical energy to reception of reflected optical energy. A control circuit monitors the flight time signal and outputs a position signal indicating position of the movable object with respect to the target.

Abstract: A method is provided to automatically control a cranes's rider block lifte and taglines. Current position of the crane's rider block is determined in terms of its horizontal and vertical coordinates, as well as in terms of the inhaul angle of the liftline. A matrix is then generated that defines i) incremental change in the rider block's horizontal coordinate with respect to incremental change in each of the boom angle, a length of the liftline and a length of the taglines, ii) incremental change in the vertical coordinate with respect to incremental change in each of the boom angle and lengths of the liftline and taglines, and iii) incremental change in the sine of the inhaul angle with respect to incremental change in each of the boom angle and lengths of the liftline and taglines. A vector defining velocity criteria for the rider block is provided. The velocity criteria is defined in terms of horizontal motion of the rider block, vertical motion of the rider block and rate of change of the inhaul angle.

Abstract: A device for providing an acoustic signal to a patient when a predetermined load is placed on the patient's foot comprises a fluid filled control ms with a first bladder underlying the patient's foot and a second bladder as interconnected via a flexible tube. The second bladder is adapted to actuate a signaling means comprising a resiliently supported and biased click spring that provides an audible click noise when actuated by the second bladder of the control means at a predetermined pressure of the liquid corresponding to a predetermined load as placed on the patient's foot.

Abstract: A fork lift truck capacity monitor or alerting device informs operators of the weight on the forks and fork height and alerts operators whenever truck speed is above creep with the forks raised above a collapsed height or whenever the forks are raised above a recommended height for a given load. The alerting device includes a control circuit that receives inputs from a speed sensor, a fork height sensor and a weight sensor and reads a memory storing data correlating load weights with maximum recommended fork heights. A truck icon is displayed on a display panel. A plurality of height zone lamps representing the weight of the load on the forks are arranged in a vertical column over the truck icon and selectively illuminated according to the load on the forks.

Abstract: Tele-operated machine including a moveable structure and a control device functionally connected to the moveable structure for operation by a human operator. An input processor apparatus responsive to the control device generates signals to move the moveable structure in a reduced vibration fashion. In a preferred embodiment, the tele-operated machine is a crane. The operator can cause fixed length incremental movements of a load supported by the crane to be accomplished with reduced levels of vibration after the move is completed.

Abstract: A weight sensing means for a forklift includes an elongated sleeve having a closed end and an open end in communication with an interior chamber. The interior chamber is dimensioned to receive a forklift lifting member. A weight sensing means is received within the interior chamber and is attached to the inner surface of the sleeve. The weight sensing means is in communication with a display means mounted on the forklift dashboard allowing a forklift operator to readily determine the weight of an object resting on the forklift blades. The weight sensing means is also in communication with an audible alarm means to alert a user whenever the lifting capacity of the forklift has been exceeded.

Abstract: A method is disclosed for controlling the cutting depth and angle of an excavator bucket to excavate a surface to a desired contour. The method includes the steps of: (1) inputting data to a machine control system to define a desired contour of the excavated surface; (2) positioning the excavator bucket close to the desired contour; (3) enabling automatic control; and (4) automatically controlling movement of the excavator bucket only when the position of the excavator bucket is within a predetermined distance or angle of the desired contour. The method is used to automatically control the excavation to a desired depth if the bucket is within a predetermined distance of a desired depth. The method is also used to automatically control the angular orientation of bucket if the slope of the bucket is within a predetermined angle of a desired slope.

Abstract: The boom length measurement includes a transmitting unit mounted on the fly section of a multi-section telescopic boom, and a receiving unit mounted on the base section of the multi-section telescopic boom. The transmitting unit transmits a first and second signal having first and second transmission speeds, respectively. The second transmission speed is less than the first transmission speed. Based on a difference in transit times of the first and second signals received by the receiving unit, a length determiner determines the length of the multi-section telescopic boom. A display displays the determined length.

Abstract: A safety apparatus for a derrick on an oil drilling rig includes a cable having a first end for connection to one side of the derrick at a predetermined location spaced below the crown. A series of pulleys is secured to the oil derrick to define a predetermined path for the cable extending from the fixed first end across the derrick at the predetermined location and then down the derrick to a location adjacent the lower end. The portion of the cable extending across the derrick is positioned in the path of a traveling block as it is pulled up the derrick. An alarm device is linked to the cable to produce an output alarm signal if the cable is pulled up by the traveling block as it approaches the top of the derrick, giving the operator a warning that the traveling block should be stopped to avoid impact with the crown.

Abstract: A method and apparatus is disclosed for storing a boom pivotally mounted to a vehicle. The apparatus includes a boom actuator to actuate the boom, a boom sensor to provide a boom signal representative of the position of the boom actuator with respect to a stable reference point and an actuator control assembly responsive to a control signal to manipulate the position of the boom by retracting or extending the boom cylinder. The apparatus also includes a controller responsive to the boom signal and to provide the control signal to the actuator control assembly so the boom is automatically driven from an initial position extended at least partially away from the vehicle to a transport position in a relatively closer proximity to the vehicle by retracting the boom cylinder to drive the boom from the initial position to a transition position and then extending the boom cylinder to drive the boom from the transition position into the transport position.

Abstract: A load insulator 2, for interposition into a loaded line, comprises a plurality of mechanical links 4 connected together to form a chain, and an electrical insulator 8 arranged between a pair of adjacent interlocked links 10,12 in the form of an insert of insulative material to electrically isolate the links 10,12 of the pair from each other. A load sensing device may be provided for sensing the strain on the mechanical link. A measuring device 24 for measuring the resistance of the insulator 8 is provided to check the electrical condition of the load insulator, whilst a recording and indicating device allows for recording of electrical strikes and provide a lifetime expiry indicator.

Abstract: An object of this invention is to improve safety in a crane. A boom control signal .alpha.r and a winch control signal .beta.r are simultaneously outputted to, respectively, a boom drive portion and a winch drive portion of a driving portion 30 for obtaining, respectively, target values Xr, Yr, with current working radius X and lift Y that vary according to the flexure of boom 4 as feedback amounts, thereby a boom hoisting angle and a rope length being controlled simultaneously.

Abstract: A method of deactivating an electronic load oscillation dampener on a crane when the crane is reverse plugged is present. Thus allowing the crane to stop faster in emergency situations.

Abstract: A method of automatically deactivating an electronic load oscillation dampener on a crane is presented. In the method, an inching time interval K is determined. In response to motion commands from the crane operator, carriage motion is initiated under the control of the load oscillation dampener so that load swing will be minimized. At the moment motion commands are removed, it is determined whether the time K has expired since the initiation of carriage motion. If the time K has expired, then the load oscillation dampener is deactivated allowing faster and more intuitive response of the crane to operator commands, including a rapid deceleration to a stop. If the time K has not expired, then the load oscillation dampener is kept active, causing load oscillations to be damped for the remainder of the run.

Abstract: A suspended load swaying and vibration preventing apparatus for simultaneously controlling prevention of swaying of a suspended load and suppression of vibration of a structural body is provided in a container crane or the like. A trolley position and a trolley velocity are detected by a trolley position detector and a trolley detector. A swaying shift and a swaying velocity of the suspended load is detected by an image sensor. Furthermore, a shift and a velocity of a structural body is detected by a structural body vibration detector. A controller receives the detection signals from these sections, calculates the optimum trolley velocity based upon a control theory and outputs a trolley velocity command. Then, a trolley drive device is driven in accordance with the trolley velocity command from the controller. The suspended load is delivered to a desired position in a stable manner under the condition that swaying of the suspended load and the vibration of the structural body are suppressed.

Abstract: To prevent a collision between first and second mobiles, such as travelling cranes, on a common movement path, a method implemented in the first mobile entails measuring a first distance between the first mobile and an origin in a fixed system of axes and a second distance between the first and second mobiles. The method comprises the steps of determining a first speed of the first mobile in the system of axes and a second speed of the first mobile relative to the second mobile in order to deduce a third speed of the second mobile in the system of axes, then of estimating a safety margin between the first and second mobiles, then of comparing the safety margin with a threshold to generate a collision risk factor, and finally of deciding on an action at drive motors of the first mobile as a function of the sign of the first, second and third speeds and the collision risk factor.

Abstract: A load insulator 2, for interposition into a loaded line, comprises a plurality of mechanical links 4 connected together to form a chain, and an electrical insulator 8 arranged between a pair of adjacent interlocked links 10,12 in the form of an insert of insulative material to electrically isolate the links 10,12 of the pair from each other. A load sensing device may be provided for sensing the strain on the mechanical link. A measuring device 24 for measuring the resistance of the insulator 8 is provided to check the electrical condition of the load insulator, whilst a recording and indicating device allows for recording of electrical strikes and provide a lifetime expiry indicator.

Abstract: A system for and method of monitoring the operation of a boom are disclosed. A first parameter is sensed, the first parameter being indicative of a load on a first boom component. It is determined from the sensed first parameter when a load supported by the first boom component exceeds a predetermined value. Information, indicative of one or more occurrences of loads on the first boom component which exceed the predetermined value, is stored. Based upon the stored information, an output is provided which is indicative of whether a boom warranty is in effect.

Abstract: The velocity of a working tool of a hydraulic excavator can be automatically decelerated and stopped just before the working tool would encounter an obstacle. Hazard regions and decelerating regions which correspond upward, downward, forward, and other positions of the hydraulic excavator are designated and a working tool decelerating pattern V.sub.2 where the working tool velocity decreases from 100% to 0% in a decelerating region is stored in a control unit. When a working tool velocity V.sub.1 which corresponds to the amount of operations of working tool levers (1, 2) intersects with the working tool decelerating pattern V.sub.2 in a decelerating region, the working tool moves at the velocity V.sub.2 and stops just before a hazard region. A restoring pattern where the working tool is restored from a just-before-hazard position to a safety region is stored as a working tool accelerating pattern V.sub.4 where the working tool velocity accelerates from a predetermined velocity just before a hazard region.

Abstract: An apparatus controlling an overhead crane in a manner that reduces the likelihood that the crane and objects suspended therefrom will contact another object. This apparatus comprises a standard control panel for controlling the speed and direction of the crane based on a plurality of operator control signals and a collision avoidance system.

Abstract: An automatic signaling system from a tractor-trailer being accidentally lifted with the cargo by the overhead traveling crane includes a height-change sensor for triggering a pulse generator which drives a strobe light that is seen by a discriminator mounted above on the crane. The discriminator is coupled into the hoisting circuitry only and does not affect the "lowering" circuitry; it will interrupt hoisting only if the discriminator sees strobe flashes of a particular predetermined frequency and pulse duration.

Abstract: A safety apparatus for use on a hoisting crane used to hoist cargo from cargo transport trucks that detects hoisting such trucks and renders the hoisting mechanism inoperative. The safety apparatus includes sensors responsive to an unsafe condition in such trucks to generate a safety signal. A transmitter responsive to the safety signal transmits an operational signal to the hoisting crane that upon receiving and recognizing the operational signal renders the hoisting mechanism inoperative and alerts the crane operator of the unsafe condition.

Abstract: A system for monitoring the operation of a boom is disclosed. The boom has at least one boom section, with each boom section being supported by an actuator assembly such that a load supported by a particular actuator assembly is representative of operation of a corresponding boom section and of a total load experienced by that boom section. A first parameter is sensed, the first parameter being indicative of a load supported by a first actuator assembly. It is determined from the sensed first parameter when a total load supported by the first actuator assembly exceeds a predetermined value. Information, indicative of one or more occurrences of total loads exceeding the predetermined value, is stored. Based upon the stored information, an output is provided which is indicative of a cause of boom failure.

Abstract: For use where a hanging load 81 is vertically hung and released with a crane having either a jib or a boom which can be raised or lowered, or where a long hanging load 81 is raised from its lowered state to its vertical state so as to be hung-up and released a control device of the has a control section for performing automatically the raising of the jib 60 or boom 61 and the winding-up or -down of the winding-up rope 70, in cooperation with each other in response to their initial states. In case that the initial angle of the jib or boom is large or small, it is controlled in such a way as a rate of variation of the hanging load .DELTA.T applied to the winding-up rope 70 becomes constant. It positions the extreme end of the jib or boom on the vertical line passing through a center of gravity of the hanging load. With such a control device, the handing load is not oscillated and a smooth vertical releasing is carried out.

Abstract: Sensors mounted on respective cargo transport trucks transferring cargo to a hoisting crane and responsive to an unsafe condition in such trucks to generate an electrical safety signal to be transmitted to such crane for rendering the hoisting mechanism inoperative.

Abstract: Apparatus for controlling the movement of hydraulically movable work equipment that is arranged at the end of a length-adjustable and pivotable arm, along a substantially rectilinear path of movement, the work equipment being moved with the assistance of hydraulic drive units that act on the arm in dependence on input control signals that determine the path of movement. Even in the case of non-ideal control loops for the control of the drive units, it is intended that the work equipment be moved along a desired path. For that purpose, starting from an actual position of the work equipment, a sequence of desired positions in the path of movement is ascertained and the work equipment is moved from an actual position to the next desired position, the movement into the next position not being initiated until the work equipment is located in a predetermined tolerance band about the preceding position.

Abstract: An excavator includes an upper structure swingably supported by a lower structure. A worker position sensor consists of a plurality of radio frequency transceivers provided in the excavator and a radio frequency transceiver carried by each of the excavation workers working within the working range of the excavator. A signal processing unit determines whether the relative distance between each worker and the excavator is either of short distance, slightly long distance or long distance and identifies the position of each worker for each of the predetermined identifying areas. A determining signal from the signal processing unit is supplied to a control unit. The control unit is connected to a drive unit which includes electro-hydraulic proportional valves for energizing actuators for positioning, swing, and traveling of the excavator. This control unit is also connected to a machine sensor which includes a swing angle sensor, a traveling level sensor, and a swing operation lever sensor.

Abstract: A posture adjusting mechanism according to the present invention is used for a cargo handling device for a cargo truck in which an arm member is mounted in such a manner that it can swivel about a vertical shaft provided on an upper end portion of a pole member, such as a pole, mounted on a bed of the cargo truck upright and above a cab of the truck and in which a cargo supporting member, such as a hook, hangs from the distal end of the arm member in such a manner that it can be raised or lowered freely. The vertical shaft provided on the upper end portion of the pole member so as to swivel the arm member thereabout is made pivotal relative to a vertical axis.

Abstract: A boom apparatus for use in lifting and transporting a payload includes a boom pivotally mounted on a support structure and including base and outer boom sections, the outer boom section being telescopically received within the base boom section and being movable axially relative to the base boom section. Sensors are provided for sensing the total length of the boom and the total moment load experienced by the boom, and an electrical warning and control circuit generates a warning signal either when the load as sensed is greater than a first predetermined value and the total length of the boom as sensed is less than a predetermined length, or when the load as sensed is greater than a second predetermined value and the total length of the boom as sensed is greater than the predetermined length, the second predetermined value of the load being less than the first predetermined value.

Abstract: In a method for the generation of control signals in a push button box and transmission of the signals for the control of a machine, signals representing the position of a push button element are transferred by a non-contacting mode from the push button element to a signal generating unit, which is adapted to produce control signals proportional to the position of the push button element. A push button box for carrying out the method comprises at least one push button element, a signal generating unit adapted to receive the signals representing the position of the push button element by non-contacting mode, and further adapted to generate control signals proportional to the position of each of the push button elements, and a partition between each push button element and the signal generating unit.

Abstract: An apparatus for suppressing vibratory or quaky movements in travel of mobile type cranes, which facilitates the operation of re-starting the vehicle after temporarily stopping the engine, for example, at a gas station for fuel replenishment as well as operations for switching the mode of operation between vehicle travel and working modes. The apparatus includes for this purpose a memory means for storing at least information as to the mode of operation under engine working conditions before an engine cut-off, and a controller adapted to reproduce automatically the mode of operation before the engine cut-off, by setting a mode selector means in a reproducing position upon re-starting the engine based on the information stored in the memory means.