CRANE LOAD AND RADIUS INDICATING SYSTEM

• US 3,819,922 A
• Filed: 05/02/1973
• Issued: 06/25/1974
• Est. Priority Date: 05/02/1973
• Status: Expired due to Term

• Current Assignee: Raymond J. Slovacek, Robert Horn
• Original Assignee: Raymond J. Slovacek, Robert Horn
• Inventors: Horn, Robert, Slovacek, Raymond J.
• Primary Examiner(s): Ruggiero, Joseph F.
• Application Number:
  US05/356,702
• Time in Patent Office: 419 Days
• Field of Search: 235/193,186,150.2,151,151.33 340/267C,272,282 37/116,189,DIG.1 212/2,39A 116/124F
• US Class Current: 701/50
• CPC Class Codes: B66C 23/905 electrical
• CPC Class Codes: E02F 9/26 Indicating devices E02F5/145 takes precedence

Abstract

Separate modular units, including a main tensiometer, a boom angle transducer, a control logic module, a combined boom radius readout and a degree of safe load meter unit, and combined actual load and allowable load readout unit, are operatively connected to a boom-type crane. The units are electrically interconnected by suitable cables that are shielded and insulated from the crane. The control logic module contains a transistorized solidstate circuit that receives, amplifies, and converts analog signals from the boom angle transducer and from a selected one of the tensiometer units, to corresponding digital signals that are continuously and automatically processed with data read from a selected memory module in which information based on the configuration of the crane in use is stored. Digital signals are produced for use in operating the digital radius readout, the allowable load readout, and the actual load readout, respectively, as well as digital signals corresponding to the ratio of the allowable loads. The resulting digital safe load signals are then converted to corresponding analog signals for use in operating the degree of safe load meter.

Claims

1. An automatic load and radius indicating system for boom type cranes comprising, a degree of safe load indicator, a load radius display, a line tensiometer, a boom angle transducer, control/logic circuit means including memory means programmable with data based on the configuration of the crane in use, and control circuit means for continuously calculating from signals based on the outputs of said angle transducer and of said tensiometer, and of the memory circuit means, signals corresponding to the load radius and degree of safe load being handled by the crane at the time for operating the corresponding indicator and display in accordance therewith.

2. The systEm as defined by claim 1, in which the safe load indicator comprises an arcuate dial calibrated in percent of safe load corresponding to the ratio of actual load to allowable hook load on the line in use multiplied by 100, and a pointer rotatable about an axis at the center of said dial which is controlled by an analog signal from said control circuit, the logic circuit comprises an analog/digital (A/D) converter circuit for receiving the output signal of said transducer, a load table memory circuit connected to said converter circuit, an allowable load computer-calculating circuit connected to said memory circuit, an analog/digital converter circuit for receiving the digital output signal of said tensiometer, and a solid state divider circuit for dividing the digital output of said allowable load circuit by the digital output of the converter circuit and multiplying the resulting ratio by 100 for controlling the rotation of said pointer to indicate on said dial the percent of safe load.

3. The system as defined by claim 2, in which the configuration of the crane programmed into the memory circuit means includes operation of a jib pivoted to the free end of the boom, and the corresponding jib line for hoisting lighter loads than those normally handled by the boom per se, whereby the indicator shows the percent of safe load and the true load radius notwithstanding the complicated trigonometric functions involved in the automatic process of calculating the desired information, said jib/whip line comprising a part having the tensiometer associated therewith for continuously measuring the tension thereon corresponding to the relative hook load on such line;

and a buffered amplifier circuit for amplifying the corresponding analog output of said tensiometer before application to the corresponding A/D circuit.

4. The system as defined by claim 3, in which the memory circuit means comprises a selected one of a plurality of separate memory modules, each corresponding to an individual crane configuration, and switch circuit means for supplying a desired crane parameter for use in said logic circuit as may be desired for safe operation by the crane operator.

5. The system as defined by claim 4, in which a digital display of allowable crane load is also provided along with a circuit connected to said comparator for conducting digital signals therefrom to the allowable load digital display for operating the latter to show the allowable load for safe operation of the crane under the existing conditions of operation thereof.

6. The system as defined by claim 1, in which the digital load radius display comprises, bold-faced individual digits indicating the number of feet of the actual load radius, and flashing illumination means for warning the operator of the crane that he is operating outside the load table.

7. The system as defined by claim 5, in which the allowable load display comprises, bold-faced individual digits indicating the number of pounds of the allowable load.

8. The system as defined by claim 3, in which the upper range of calibration of the percent of safe load indicator dial is colored yellow and then red to show when the allowable load limit is approached by the moving pointer of the indicator.

9. The system as defined by claim 2, in which the allowable load circuit comprises, a lower load selecting solid state comparator circuit provided with a manual load set input circuit for providing a digital signal corresponding to a desired load limit for comparison with the digital signal output and producing a digital signal corresponding to the allowable load.

10. The system as defined by claim 2, in which the allowable load circuit comprises a multiplexer circuit connected the output of said comparator circuit, a de-multiplexer connected to the output of said multiplexer, a latch circuit connected to the output of said de-multiplexer circuit, a decoder/driver circuit connected to latch circuit, and an allowable load display operated by said decOder/driver circuit, comprising bold-faced numbers corresponding to the load in pounds.

11. A load and radius indicating system for boom type cranes, comprising:

a boom angle transducer unit adapted to be mounted on the boom of the crane, a load line tensiometer unit adapted to be associated with a selected load bearing line of such crane, a control/logic unit adapted to be mounted on an inner wall of the cab of such crane responsive to outputs of said angle transducer and load line tensiometer for producing signals indicative of load radius and percent of safe load, a load and radius indicator unit responsive to said control/logic outputs, comprising a percent of safe load meter and continuous load radius digital readout in appropriate units, adapted to be mounted within such cab in front of the operator, and insulated and shielded cable means for electrically interconnecting said units.

12. The system as defined by claim 11, including an auxiliary allowable load and an actual load indicator unit adapted to be mounted within such end adjacent to the percent of safe load and load radius indicator unit, comprising, a continuous digital readout in pounds of the allowable load, a continuous digital readout in pounds of the actual load as the latter is hoisted by the crane, and connector means for electrically connecting said auxiliary unit to the main display unit.

13. A system as defined by claim 11, in which the control/logic unit comprises, a front panel provided with potentiometer adjusting screws for calibrating different functions of the system, test jacks for checking different parts of the system, a digital parts-of-line selector, a digital signal generating manual load limit set selector, and an instruction card corresponding to the particular configuration of the crane with which the system is to be used.

14. A system as defined by claim 11, in which the load and radius indicator unit comprises, a front panel provided with a manually adjustable rotary control knob having separate lamp test, main line, jib/whip, and OFF stations.

15. A load and radius indicating system as defined by claim 11, in which the boom angle transducer unit comprises, a pendulum oriented arcuate potentiometer providing zero output of zero degree boom angle, as measured from the horizontal, and a maximum output signal when the boom is near a vertical position, a slide-contact on said potentiometer for providing a linear voltage output with a minimum sensitivity of 35*, whereby an incremental change in the angle of the boom as small as 20 minutes is detected with a corresponding output signal change to the control/logic unit.

16. A system as defined by claim 15, in which the control/logic unit comprises, an adjustable-gain buffered amplifier connected to the output of said potentiometer for amplifying such voltage output, an analog/digital converter connected to the output of said amplifier for continuously converting the analog signal from said transducer as the boom angle changes during operation of the crane, and cosine ROM and load ROM circuits programmed to automatically calculate digital outputs corresponding to the load radius and allowable load continuously during load hoisting operation of the crane.

17. The system as defined by claim 16, in which the control/logic unit also comprises, a comparator circuit for developing from the manual load set signals and digital signals from said load ROM circuit, the lower of the two for use by the allowable load digital readout.

18. The system as defined by claim 17, in which the control/logic unit includes an adjustable gain buffered amplifier connected to the output of said tensiometer unit for amplifying the load signal, an analog/digital converter for converting such amplified load signal from an analog to a digital mode, a multiplier for multiplying the digital load signals by a digital signal corresponding to the-line-parts, which digital signal product corresponds to the actuaL line load on the tensiometer unit, for display by said actual load readout, a divider for dividing such actual load digital signal corresponding to the allowable load signal from said comparator, and a digital/analog converter for converting the resulting digital signal to the analog mode which is used to operate said percent of load meter.

19. A system as defined by claim 13, in which the control/logic unit front panel includes a jib/whip switch, a jib/whip load line tensiometer unit, and circuit means for connecting said jib/whip tensiometer into the system.

20. A safe load indicator system for cranes comprising, a solid-state control/logic module unit including transistorized amplifier circuit means for amplifying analog signals corresponding to operating conditions of the crane, transistorized converter circuit means for substantially instantaneously changing such signals to corresponding digital signals, transistorized computer calculating circuit means for automatically processing such signals to produce digital signals based on the configuration of the crane for use by different indicators of desired safe load operating conditions of the crane during operation thereof, said system further including;

a boom angle transducer for providing analog signals corresponding to the boom angle of the crane, main line and jib/whip line tensiometers measuring line tension for providing analog signals corresponding to selected main hook and swing hook loads on the crane, and switch means for manually selecting one or the other of such hook load signals as may be required for proper operation of the system.

21. A system as defined by claim 20, in which the system includes memory storage means comprising modules programmed to correspond to the parameters of configuration of the different cranes with which the system can be used, which are necessary for the correct operation of the control logic circuit, whereby the system can be quickly adapted to a selected one of a plurality of cranes of varying configuration.

22. A system as defined by claim 20, in which an information display unit is located in the crane cab comprising, an analog signal responsive bold-faced moving indicator for showing the percent of safe load as an actual load is handled by the selected hook, a large illuminated digital readout for showing the load radius in feet, and solid state circuit means for converting the corresponding digital signals to analog signals for use by said indicator.

23. A system as defined by claim 22, in which illuminated digital readouts are provided for the actual load and allowable load in appropriate units during operation of the crane.

24. A system as defined by claim 23, in which the control/logic module unit comprises, a circuit testing and manually adjustable means for setting the boom length, parts-of-line, main load limit, and calibration of main load and jib/whip line tensiometer circuits.

25. The system of claim 20, in which the line tensiometer and boom angle transducer units supply the analog signals to the input of the control/logic units, and said control/logic unit includes separate solid state circuit means for first amplifying and then converting the analog signals to corresponding ditigal signals, solid state circuit means for continuously processing the digital boom angle signals to thereby produce corresponding digital signals for operating said digital load radius readout, additional solid state circuit means for further processing the digital boom angle signals with the digital line tensiometer signals to produce digital signals corresponding to the percent of safe load on the crane, and solid state circuit means for then converting such digital percent of safe load signals to corresponding analog signals for operating said percent of safe load meter.