US3351945A

US3351945A - Safety remote control for a carrier

Info

Publication number: US3351945A
Application number: US343411A
Authority: US
Inventors: Vincent S Borsattino; Chursel E Marker; Jesse W Shalla
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1964-02-07
Filing date: 1964-02-07
Publication date: 1967-11-07
Anticipated expiration: 1984-11-07
Also published as: ES309041A2; DE1513669A1; GB1091372A

Description

United States Patent 3,351,945 SAFETY REMOTE CONTROL FOR A CARRIER Vincent S. Borsattino, Chursel E. Marker, and Jesse W.

Shalla, Gary, Ind., assignors to United States Steel Corporation, a corporation of Delaware Filed Feb. 7, 1964, Ser. No. 343,411 3 Claims. (Cl. 343-225) ABSTRACT OF THE DISCLOSURE A safety remote control for a carrier wherein the transmitter transmits two signals of substantially different frequency and the receiver for the safety signal includes a first tuned circuit tuned to the safety signal frequency and a second tuned circuit tuned to and inductively coupled to the first tuned circuit.

This invention relates to a safety remote control for a carrier and more particularly to a control for directing the movements of overhead cranes and locomotives from a remote position. A similar control system is shown in our co-pending application Ser. No. 337,037 filed Jan. 10, 1964. The control system of the present application is particularly directed to safety features. While our co-pending application has safety features which will prevent accidental operation of the control under most all conditions, the carrier signal is applied in such a manner that the manual magnetic disconnect is energized and crane move ment accomplished by modulating the carrier signal. In some instances random noises might possibly cause movement of the carrier. The random noise might be an arc welder or other equipment found in a steel mill although in several months operation of the control of our co-pending application there has been no operation of the crane due to random noises. The safety control of the co-pending application also requires a superhetrodyne safety receiver which is relatively expensive.

It is therefore an object of our invention to provide a carrier control system which eliminates the need of a superhetrodyne safety receiver.

Another object is to provide such a control which cannot be actuated by random noises.

These and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a schematic view of a transmitter used with our invention;

FIGURE 2 is a schematic view of a crane with certain control parts shown therein; and

FIGURE 3 is a schematic view of the receiver of our invention and the motor controls associated therewith.

Referring more particularly to FIGURE 1 of the drawings, reference numeral 2 indicates a battery or other low voltage source. Power from the battery 2 is delivered to variable frequency multi-vibrators 4A, 4B, 4Cand 4D. Output switches'6A, 6B, 6C and 6D are provided for the multi-vibrators 4A, 4B, 4C and 4D. The outputs of the multi-vibrators are selectively connected to an audio amplifier 8 and the output of audio amplifier 8 is applied to an audio frequency amplifier 10 having an antenna 12 associated therewith. The output of an oscillator 14 is ap plied to the audio frequency amplifier 10. Also connected to the battery 2 is a safety channel transmitter 16 having an antenna 18. Flow of power from the battery 2 to the various parts is controlled by means of a switch 19. The transmitter shown diagrammatically in FIGURE 1 and described above is the same as in our above identified co-pending application. However, any suitable transmitter may be use.

While the invention may be used to operate any type of ice mobile equipment it will be described with reference to an overhead crane carried on rails 20. The crane includes a bridge 22 which moves along the rails 20, a trolley 24 which moves transversely of the bridge and a hoist 26 mounted on thetrolley 24. The bridge 22 is moved by means of a motor 28 having a control panel 30 for determining the direction and speed of its movement. The trolley 24 is moved across the bridge 22 by means of a motor 32 whose speed and direction of movement are determined by means of a control panel 34. The hoist 26 is raised and lowered by means of a motor 36, the speed and direction of movement of which is controlled by means of a control panel 38. The

control panels

30, 34 and 38 contain the usual control relays which are used to energize their respective motors for movement in forward and reverse directions at various speeds. The parts of the crane so far described are conventional. A superheterodyne receiver 40 having an antenna 40T is mounted on the bridge 22.

FIGURE 3 shows diagrammatically the receivers and control circuits. The output of the superhetrodyne 40 is impressed on a detector 42 which in turn has its output connected to a limiter 44. The limiter 44 includes a. capacitor 45 connected to base 46B of transistor 46 and also through a capacitor 50 and resistor 52 connected in series to the negative terminal of a power source 54. Emitter 46B is connected through resistor 56 to emitter 58E of transistor 58. Collector 58C is connected to the negative terminal of power source 54 through a resistor 60 and to the primary 62F of transformer 62. A shaper 64 includes secondary 62S of transformer 62 which is connected through a choke 66 to primary 68P of transformer 68.

The ouput shaper 64 is connected to

discriminators

70A, 70B, 70C and 70D. The

discriminators

70A, 70B and 70C are identical except for values of components and their outputs are connected to servo-amplifiers 72A, 72B, 72C,respectively. The servo-amplifiers 72A, 72B and 72C operate segmented

rotary switches

74A, 74B and 74C, respectively, which in turn are connected to control the operation of intermediate panels 76A, 76B and 76C,

respectively. The

intermediate panels

76A, 76B and 760 are connected to

control panels

30, 34 and 38, respectively. The intermediate panels 76A, 76B and 76C contain relays having contacts capable of handling the heavy currents needed to operate the relays of the control panels. Power for the intermediate panels and control panels are provided from control power lines L1, L2. The parts of FIGURE 3 so far described are the same as in our above identified co-pending application.

According to the present invention a resistor 78 is connected to the negative terminal of power source 54 in series with resistor 60 and a silicon controlled rectifier 80 is connected between the

resistors

60 and 78 and also tothe negative terminal of power source 54. The rectifier 80 is also connected in series with a current sensitive relay coil 82 and relay contact 84C to the positive terminal of power source 54. Relay coil 82 has a normally open contact 82C which is connected in line L1 leading to

control panels

30, 34 and 38. Contact 84C is controlled by a voltage sensitive relay coil 84 which also operates contact 84C1. Contacts 84C and 84C1 are both normally open. Contact 84C1 is connected to the positive terminal of power source 54 in series with a current sensitive'relay coil 86 which has a normally open contact 86C in power line L1 leading to intermediate panels 76A, 76B and 76C.-

nected in parallel with resistors 90 and 92. Base 94B is connected to a resistor 98. Resistor 100 is connected in parallel with resistors 90 and 92 and resistor 102 is connected in parallel with resistor 96. A capacitor 104 is connected in parallel with resistor 102. A diode rectifier 106 is connected in series with a variable capacitor 108 across capacitor 104. An inductor 110 is connected in parallel with variable capacitor 108. A safety channel receiving antenna 112 is connected in series with

variable capacitors

114 and 116 to ground. Inductor 118 is connected in parallel with capacitor 116. Capacitor 108 and inductor 110 constitute one tuned circuit 120 and capacitor 116 and inductor 118 constitute another tuned circuit 122. Both circuits are tuned to the same resonant frequency but are individually adjustable.

In operation, when the operator wishes to warn other workmen of the movement of the crane he closes

switches

6D and 19 so that the multivibrator 4D oscillates and applies a signal to the audio amplifier 8 which amplifies the signal and applies it to the RF amplifier 10. This signal is modulated on the carrier freqency which is generated in the oscillator 14 and is transmitted through the air waves by means of antenna 12. This signal is picked up by antenna 40T and is fed into the receiver 40 where this incoming signal is mixed with a signal from the oscillator forming part of the receiver 40. The output of the receiver 40 is detected by detector 42 and is then amplified and limited by the limiter 44. The limiter 44 transmits the audio portion of the wave shaped signal to the sharper 64 where it is turned into a sine wave which is impressed on

discriminators

70A, 70B, 70C and 70D. Nothing occurs in discriminators 70A, 70B and 700 because they are not tuned to the frequency of multi-vibrator 4D. However, discriminator 70D is tuned to the frequency of the multivibrator 40 so that the bell, not shown, is caused to ring in the same manner as in our above entitled co-pending application.

Assuming that it is desired to move the bridge 22 forwardly, the operator moves switch 6A to the broken line position shown in FIGURE 1 and at the same time adjusts the frequency of the multi-vibrator 4A in the desired direction to move the bridge motor 28 at the desired speed in the desired direction. Switch 19 is also closed at this time. The output signal of multi-vibrator 4A will be sent through in the same manner as that of multi-vibrator 4D previously described. However, the frequency of this signal will be different than that of multi-vibrator 4D and will' be the same frequency as discriminator 70A. As transistor 58 goes into conduction there is a voltage drop across resistor 60 and also across resistor 78.

Resistors

60 and 78 form the collector load for transistor 58 and also make up a voltage divider network for the silicon controlled rectifier 80. As the voltage drops across resistor 78, current flows and causes silicon controlled rectifier 80 to go into conduction. When silicon controlled rectifier 80 is conducting and contact 84C is closed, relay coil 82' will be energized to close contact 82C, this applying power to the control panel 30 which will in turn allow movement to occur provided contact 86C is closed. At the same time a signal from safety channel transmitter 16 is picked up by antenna 112 and coupled through the variable capacitor 114 into tuned circuit 122. The signal developed in tuned circuit 122 is then inductively coupled into tuned circuit 120. The positive portion of the signal is then passed through the rectifier 106 and biasing resistor 98 onto the base electrode 94B of transistor 94. Condenser 104 connected inparallel with resistor 102 acts as a filter and biasing network for transistor 94. Resistor 96 acts as a current limiting resistor. Resistor 100 acts as part of the voltage dividing network for biasing base electrode 94B of transistor 94. Resistors 90 and 92 form the collector load of transistor 94 and also form a voltage divider network for the silicon controlled rectifier 88. As the incoming signal develops a voltage across resistors 90 and 92, transistor 94 conducts and causesrelay 84 to close its contacts 84C and 8401. Closing of contact 84C energizes relay coil 82 and closing contact 84C1 energizes relay coil 86. As a voltage is developed across resistor there is suflficient current to trigger silicon controlled rectifier 88 which will close relay contact 86C. The closing of

contacts

82C and 86C will apply power to the intermediate panels 76A, 76B and 76C and to control

panels

30, 34 and 38. Thus the signal which is picked up by discriminator 70A will be delivered to servo-amplifier 72A so that the motor 28 will rotate to cause the bridge to move at the desired speed in the desired direction. When the crane reaches its desired position the operator moves switch 6A to the solid line position shown and the movement of the crane will cease. If the trolley 24 is not in the desired position the operator will move switch 6B to its broken line position and adjust the frequency of multivibrator 4B to the position where operation of motor 32 will be that desired. The frequency of the generated signal will be only within the frequency response of discriminator 708 so that the output of discriminator 7 0B will be impressed on the servoamplifier 72B and switch 74B will control movement of the motor 32 to move the trolley in the desired direction. When the trolley 24 reaches its desired position the switch 6B will be moved to its solid line position and movement of the trolley will cease. The hoist 26 is then lowered by the operator moving the switch 60 to the broken line position and adjusting the frequency of the multi-vibrator 4C as desired. The signal will then be transmitted in the same manner as that described above and picked up by discriminator 70C and the output of discriminator 70C will be impressed on servo-amplifier 720 which through the switch 740 will cause operation of motor 36 to lower the hoist. When the hoist 26 reaches the desired position the operator moves switch 6C to the solid line position stopping the movement of the hoist. He then attaches the article to be lifted to the hoist and assuming that the crane is to be returned to its original position the above de scribed operations are repeated in reverse order. The only difference is that the multi-vibrators 4A, 4B and 4C are adjusted to a different frequency. It will be seen that except for the safety receiver and the operation of the as sociated safety devices the operation of the control is the same as in our above identified application. Also the improvement of the present application can be used when a single control signal is utilized.

While one embodiment of our invention has been shown and described it will be understood that other adaptations and modifications may be made without departing from the scope of the following claims.

We claim:

1. A control for a carrier comprising a first transmitter for transmitting a first signal of known frequency, a second transmitter for transmitting a second signal having a frequency substantially different than that of the first transmitter, said transmitters being at a position remote from said carrier, a first receiver mounted on said carrier for receiving the signal transmitted by said first transmitter, a detector connected to the output of said first receiver, a limiter connected to the output of said detector, said limiter including a first transistor connected to receive the output of said detector, discriminator means connected to the output of said limiter for detecting and distinguishing the frequency of said first signal, an electrical powered device, second means operable by the output of said discriminator means for operating said device, a silicon controlled rectifier connected in circuit with said transistor and switched on by said transistor, a power source, a first relay coil connected in series with said silicon controlled rectifier to said power source to allow current to pass through said relay coil when the silicon controlled rectifier is turned on, a first tuned circuit tuned to the second signal frequency for picking up a signal from said second transmitter, a second tuned circuit tuned to the frequency of said first tuned circuit and inductively coupled thereto, rectifier means connected to the output of said second tune-d circuit for passing one portion of the output signal, a second transistor, a second relay coil connected in series with said second transistor to said power source, means connecting the output of said rectifier means to said second transistor to switch the transistor on and allow current to pass from said power source to said second relay coil, power supply means for said devices, and a normally open contact associated with each of said relay coils, said relay coils closing said contacts when they are energized to permit flow of electricity from said power supply means to said electrical powered device when said second means is operable.

2. A control for a carrier comprising a first transmitter for transmitting a first signal of known frequency, a second transmitter for transmitting a second signal having a frequency substantially different than that of the first transmitter, said transmitters being at a position remote from said carrier, a first receiver mounted on said carrier for receiving the signal transmitted by said first transmitter, a detector connected to the output of said first receiver, a limiter connected to the output of said detector, said limiter including a first transistor connected to receive the output of said detector, discriminator means connected to the output of said limiter for detecting and distinguishing the frequency of said first signal, an electrical powered device, second means operable by the output of said discriminator means for operating said device, a silicon controlled rectifier connected in parallel with said first transistor between the transistor collector and emitter and switched on by said transistor, a power source, a first current sensitive relay coil and a first normally open relay contact connected in series with the anode of said silicon controlled rectifier to said power source to allow current to pass through said first current sensitive relay coil when the first normally open relay contact is closed and the silicon controlled rectifier is turned on, a first tuned circuit tuned to the second signal frequency for picking up a signal from said second transmitter, a second tuned circuit tuned to the frequency of said first tuned circuit and inductively coupled thereto, a diode rectifier connected to the output of said second tuned circuit, a second transistor connected in series with said diode rectifier to switch on said second transistor, a voltage sensitive relay coil connected in series with said second transistor to said power source, said voltage sensitive relay coil operating said first normally open contact, a second normally open contact operable by said voltage sensitive relay coil, a voltage dividing network connected in series with said second transistor, a second silicon controlled rectifier, a second current sensitive relay coil connected in series with said second normally open contact to said power source, an electrical connection from said voltage dividing network to said second silicon controlled rectifier to allow said second transistor to switch on said second silicon controlled rectifier, power supply means for said devices, and a normally open contact associated with each of said current sensitive relay coils, said current sensitive relay coils closing said contacts when they are energized to permit fiow of electricity from said power supply means to said electrical powered device when said second means is operable.

3. A control for a carrier comprising a first transmitter for transmitting a first signal of known frequency,

a second transmitter for transmitting a second signal hav ing a frequency substantially dilferent than that of the first transmitter, said transmitters being at a position remote from said carrier, at first receiver mounted on said carrier for receiving the signal transmitted by said first transmitter, a detector connected to the output of said first receiver, a limiter connected to the output of said detector, said limiter including a first transistor connected to receive the output of said detector, discriminator means connected to the output of said limiter for detecting and distinguishing the frequency of said first signal, an electric motor, means operable by the output of said discriminator means for controlling operation of said motor, power supply means for said motor, a circuit connecting said power supply means to said motor, a first silicon controlled rectifier connected in parallel with said first transistor between the transistor collector and emitter and switched on by said transistor, a power source, a first current sensitive relay coil and a first normally open relay contact connected in series with the anode of said first silicon controlled rectifier to said power source to allow current to pass through said first current sensitive relay coil when the first normally open relay contact is closed and the silicon controlled rectifier is turned on, a first tuned circuit for picking up a signal from said second transmitter, a second tuned circuit tuned to the frequency of said first tuned circuit and inductively coupled thereto, a diode rectifier connected to the output of said second tuned circuit, a second transistor connected in series with said diode rectifier to switch on said second transistor, a voltage sensitive relay coil connected in series with said second transistor to said power source, said voltage sensitive relay coil operating said first normally open contact, a second normally open contact operable by said voltage sensitive relay coil, a voltage dividing network connected in series with said second transistor, a second silicon controlled rectifier, a second current sensitive relay coil connected in series with said second normally open contact to said power source, and an electrical connection from said voltage dividing network to said second silicon controlled rectifier to allow said second transistor to switch on said second silicon controlled rectifier, each of said current sensitive relay coils having a normally open contact in said motor circuit, which contacts when closed permitting operation of said motor when said second means is operable.

References Cited UNITED STATES PATENTS 3,090,959 5/ 1963 Marmont 343-225 3,103,558 9/1963 Ligotky 340-171 3,103,611 9/1963 Hooper 343-225 3,127,563 3/1964 Paulson 340-171 3,278,760 10/1966 Wagner 307-885 3,278,821 10/ 1966 Gutzwiller 307-885 OTHER REFERENCES F Oliver and W. Ehrsam-z The Gate Controlled Switch, Motorola Monitor, vol. 2, January 1964, pp. 24-28.

NEIL C. READ, Primary Examiner.

A. J. KASPER, Assistant Examiner.

Claims

1. A CONTROL FOR A CARRIER COMPRISING A FIRST TRANSMITTER FOR TRANSMITTING A FIRST SIGNAL OF KNOWN FREQUENCY, A SECOND TRANSMITTER FOR TRANSMITTING A SECOND SIGNAL HAVING A FREQUENCY SUBSTANTIALLY DIFFERENT THAN THAT OF THE FIRST TRANSMITTER, SAID TRANSMITTERS BEING AT A POSITION REMOTE FROM SAID CARRIER, A FIRST RECEIVER MOUNTED ON SAID CARRIER FOR RECEIVING THE SIGNAL TRANSMITTED BY SAID FIRST TRANSMITTER, A DETECTOR CONNECTED TO THE OUTPUT OF SAID FIRST RECEIVER, A LIMITER CONNECTED TO OUTPUT OF SAID DETECTOR, SAID LIMITER INCLUDING A FIRST TRANSISTOR CONNECTED TO RECEIVE THE OUTPUT OF SAID DETECTOR, DISCRIMINATOR MEANS CONNECTED TO THE OUTPUT OF SAID LIMITER FOR DETECTING AND DISTINGUISHING THE FREQUENCY OF SAID FIRST SIGNAL, AN ELECTRICAL POWERED DEVICE, SECOND MEANS OPERABLE BY THE OUTPUT OF SAID DISCRIMINATOR MEANS FOR OPERATING SAID DEVICE, A SILICON CONTROLLED RECTIFIER CONNECTED IN CIRCUIT WITH SAID TRANSISTOR AND SWITCHED ON BY SAID TRANSISTOR, A POWER SOURCE, A FIRST RELAY COIL CONNECTED INSERIES WITH SAID SILICON CONTROLLED RECTIFIER TO SAID POWER SOURCE TO ALLOW CURENT TO PASS THROUGH SAID RELAY COIL WHEN THE SILICON CONTROLLED RECTIFIER IS TURNED ON, A FIRST TUNED CIRCUIT TUNED TO THE SECOND SIGNAL FREQUENCY FOR PICKING UP A SIGNAL FROM SAID SECOND TRANSMITTER, A SECOND TUNED CIRCUIT AND TUNED TO THE FREQUENCY OF SAID FIRST TUNED CIRCUIT AND INDUCTIVELY COUPLED THERETO, RECTIFIER MEANS CONNECTED TO THE OUTPUT OF SAID SECOND TUNED CIRCUIT FOR PASSING ONE PORTION OF THE OUTPUT SIGNAL, A SECOND TRANSISTOR, A SECOND RELAY COIL CONNECTED IN SERIES WITH SAID SECOND TRANSISTOR TO SAID POWER SOURCE, MEANS CONNECTING THE OUTPUT OF SAID RECTIFIER MEANS TO SAID SECOND TRANSISTOR TO SWITCH THE TRANSISTOR ON AND ALLOW CURRENT TO PASS FROM SAID POWER SOURCE TO SAID SECOND RELAY COIL, POWER SUPPLY MEANS FOR SAID DEVICES, A NORMALLY OPEN CONTACT ASSOCIATED WITH EACH OF SAID RELAY COILS, SAID RELAY COIL CLOSING SAID CONTACTS WHEN THEY ARE ENERGIZED TO PERMIT FLOW OF ELECTRICITY FROM SAID POWER SUPPLY MEANS TO SAID ELECTRICAL POWER DEVICE WHEN SAID SECOND MEANS TO OPERABLE.