US3675097A

US3675097A - Remote crane motor control with variable direction and speed of movement

Info

Publication number: US3675097A
Application number: US49224A
Authority: US
Inventors: William L Mulligan
Original assignee: Parks Cramer Co
Current assignee: Parks Cramer Co
Priority date: 1970-06-24
Filing date: 1970-06-24
Publication date: 1972-07-04
Anticipated expiration: 1989-07-04

Abstract

A crane having at least one movable member and a drive for moving the movable member wherein the control for the crane permits an operator to controllably vary the direction and speed of movement of the movable member. Adaptation of the control to cranes of otherwise conventional construction or to pre-existing cranes is facilitated by an advantageous electrical circuit arrangement, in which direction and speed signals are conducted through a minimum number of electrical conductors in accomplishing the controlled variation of direction and speed of movement.

Description

United States Patent Mulligan 1 July 4, 1972 541 REMOTE CRANE MOTOR CONTROL 3,456,230 7/1969 Matthews ..310/s0 WITH VARIABLE DIRECTION AND 5 2 Br wn SPEED OF MOVEME ,17 3 19 5 Gorjanc...

NT 3,220,356 11/1965 Leslie ..318/16 UX [72] Inventor: William L. Mulligan, Charlotte, NC.

. Primary Examiner--T. E. Lynch [73] Assignee. Parks-Cramer Company, Fitchburg, Mass Attorney parrott Bey Seltzer Park & Gibson [22] Filed: June 24, 1970 [57] ABSTRACT [21] App1.No.: 49,224

A crane having at least one movable member and a drive for moving the movable member wherein the control for the [52] U.S.Cl 318/17, 318/257, 318/54 crane permits an operator to controllably vary the direction [51 Int. Cl. ..H02p 7/20 and speed of movement of the movable member. Adaptation I flf S arch ..3l8/257, 266, 51, 54, 55, 59, of the control to cranes of otherwise conventional construc- 31 1 17; 310 50; 200 157 tion or to pre-existing cranes is facilitated by an advantageous electrical circuit arrangement, in which direction and speed [56' Rderences Cited signals are conducted through a minimum number of electrical conductors in accomplishing the controlled variation of UNITED STATES PATENTS direction and speed of movement.

3,469,164 9/ 1969 Treumpter ..318/257 8 Claims, 5 Drawing Figures PATENTEDJUL 41972 SHEET 10F 2 Wm M m.

I MLJLUGAN ATTORNEY 5 PATENTEDJUL 4 m2 SHEET 2 OF 2 6 o INVENTOR: WlLUAM L. MULLJGAN q llll ATTORNEYS REMOTE CRANE MOTOR CONTROL WITH VARIABLE DIRECTION AND SPEED OF MOVEMENT The desirability of providing a variable speed movement in the motions of a crane has been recognized heretofore, but attempts at providing such variable speed movement have suffered from deficiencies and difficulties typically reflecting the relative complexity and expense of the attempted solutions. In particular, the number of conductors required in control cables or trolley bar arrangements is frequently doubled by incorporation of variable speed drives, significantly raising the cost of the crane. Further, in such previous attempts to accomplish variable speed control over the movement of a movable member of a crane, additional difficulties have been created in that the controls often differ from those normally provided with a single speed crane. A crane so equipped with a variable speed drive must be operated diflerently from other cranes not so equipped, presenting a problem in the adjustment of an operator to the operating characteristics of such a crane.

In view of such difficulties and deficiencies heretofore encountered in efforts to provide variable speed drives for cranes, it is an object of the present invention to equip a crane having a movable member and a drive for moving the movable member with controls for varying the direction and speed of the movable member with minimal addition of materials and expense to the crane and with minimal variation from conventional crane control arrangements. In accomplishing this object of the present invention, purchasers of cranes are given the possibility of selecting variable speed control at minimal additional expense. Further, such control is made available in an arrangement consistent with the operating controls of other cranes so as to reduce the confusion of operators for the crane and thereby lead toward a reduced likelihood of damage to the crane.

A further object of the present invention is to accomplish the incorporation into a crane of a controllably variable direction and speed control for the movement of a movable member of the crane while adopting and using certain construction and design practices which are conventional in such cranes. By the adoption of certain conventional practices, applied in a new combination in accordance with the present invention, the addition of variable speed controls to pre-existing cranes is facilitated and the usefulness of the present invention is broadened.

Some of the objects and advantages of the invention having been stated, others will appear as the description proceeds, when taken in connection with the accompanying drawings, in which FIG. 1 is a perspective view of a crane incorporating the present invention, in use in the handling of materials;

FIG. 2 is an enlarged perspective view of a control housing and multiconductor cable incorporated in the crane of FIG. 1;

FIG. 3 is a plan view, in partial section, through the control housing of FIG. 2, taken generally along the line 3-3 in FIG. 2 and showing a coupled together direction and speed controlling means in accordance with the present invention;

FIG. 4 is a side elevation view, in partial section, of the structure shown in FIG. 3; and

FIG. 5 is a schematic electrical diagram of a drive means and control means incorporated in the crane of FIG. 1.

Referring now more specifically to the drawings, the present invention will be described with a reference to a crane, generally indicated at 10, of the type including a lifting hook l1 movable vertically by a lifting drive motor 12 and suspended from a transversely moving carriage 14 driven by a carriage drive motor 15. The carriage 14 is supported from and movable along transverse beams 16 which extend between spaced apart longitudinal beams 18. Movement of the transverse beams 16 along the longitudinal beams 18 is accomplished by a longitudinal movement drive motor 19. Cranes of such a general type are known in the materials handling industry as three motion cranes, and are in general use in a variety of industries.

The crane 10 includes control housing means 21 depending from the carriage 14 to within reach of an operator 0, to provide the operator with a means for governing vertical movement of the lifting hook l1, transverse movement of the carriage l4, and longitudinal movement of the transverse beams 16. The control housing means 21 is interconnected with the

drive motors

12, 15 and 19 in part through means of a multiconductor cable 22 extending between the control housing means 21 and the crane l0 and in part through means of trolley conductors such as conductors 23 extending along the transverse beams 16 and providing connection with the longitudinal drive motor 19. In the illustrated embodiment for the crane, the cable 22 depends from the carriage 14, so that the operator 0 may control the crane 10 from a position relatively nearby the lifting hook 11.

The present invention contemplates the combination, with the crane 10, of manually operable direction and speed controlling means and means operatively interconnecting the manually operable control means and a drive means for a movable member of the crane 10. In the discussion which follows, attention will be particularly directed to the transverse beams 16 as a movable member of the crane l0 and to the drive motor 19 for moving the transverse beams 16. It is to be understood that the motor 19, in accordance with the present invention, is controlled to vary the direction and speed of movement of the transverse beams 16 along the longitudinal beams 18. It is, however, anticipated that the present invention is equally applicable to movement of the carriage 14 along the transverse beams 16 through the operation of drive motor 15 therefor, or the vertical movement of the lifting hook 11 in response to operation of the drive motor 12 therefor.

In order to controllably vary the direction and speed of movement of the transverse beams 16 along the longitudinal beams 18, the present invention comprises manually operable direction and speed controlling means and means operatively connecting the manually operable control means and drive motor 19 for effecting movement of the transverse beams 16 in a selected one of the first and second directions and at a selected speed in response to actuation of the manually operable control means. The manually operable control means comprises first and second coupled together direction and speed controlling means, respectively identified generally by the

reference characters

24 and 25 and housed within control housing means 21. As brought out more fully in FIGS. 3, 4 and 5, each of the direction and speed controlling means 24, 25 includes a

depressible pushbutton

26, 27 operatively connected with direction selecting switch means 30, 31 and speed selecting resistance means 32, 33.

As best shown in FIG. 5, the direction selecting switch means 30, 31 of the first and second coupled together direction and speed controlling means 24, 25 are double pole, double-throw electrical switches. Upon depression of the corresponding pushbutton, the switches are thrown to effect interconnections as described hereinafter and, with further depression, the resistance values presented by the resistance means are varied. The electrical switches 30, 31 are operatively interconnected in such a manner that the controlling

means

24, 25 are cooperatively interlocked and effective actuation of one of the controlling means is precluded during actuation of the other thereof, as is brought out more fully in the discussion which follows.

In order to accomplish movement of the transverse beams 16 of the crane 10 in a selected one of first and second directions longitudinally of the longitudinal beams 18 and at a selected speed in response to actuation of a corresponding one of the first and second controlling

means

24, 25, the controlling means are operatively connected to the drive motor 19 through electrical circuit means as illustrated in FIG. 5. As there shown, the electrical circuit means includes direction governing relay means 38, 39 for establishing first and second interconnections with the drive motor 19 and thereby for determining the direction of rotation of the armature of the motor 19 and the direction of movement in which the transverse beams 16 are driven. As will be understood, the direction governing relay means 38, 39 each include

windings

40, 50 which, when energized, displace respective

contact carrying armatures

41, 42, 44, 45 46, 51, 52, 54, 55, and 56. Certain of the armatures effected by energization of the corresponding relay windings govern the establishment of the first and second interconnections with the motor 19, and thus the energization of the motor.

More specifically, energization of the winding 40 of the first direction controlling relay 38 closes contact sets associated with two annatures 41 and 42, thereby establishing a first interconnection of the drive motor 19 with current controlling circuit means illustrated in the upper portion of FIG. 5. By the establishment of such a first interconnection, the characteristics of current flowing to the electrical drive motor 19 through a rectifier bridge are placed under the control of current controlling circuit means as disclosed more fully hereinafler. Additionally, contact sets associated with two additional armatures 44 and 45 of the first direction governing relay means 38 are opened to respectively remove a dynamic resistor from connection across the motor 19 and preclude energization of the other direction governing relay means 39. Finally, closure of a contact set associated with a fifth armature 46 electrically connects the current controlling circuit means with the speed selecting resistance means 32 actuated by the pushbutton 26 which has controlled energization of the direction governing relay means 38. Upon electrical connection of the speed controlling resistance means 32 with the current controlling circuit means, electrical current flowing to the motor 19 is controlled in accordance with the resistance value of the speed selecting resistance means, for determining the speed in which the movable member of the crane is driven. A similar operation follows depression of the pushbutton 27 and energization of the winding 50 of the other direction governing relay 39.

The electrical drive motor 19 is a reversible direct current motor supplied through a rectifier bridge with alternating current. The current controlling circuit means operates in a manner generally familiar to designers of motor controls to vary at least one characteristic of alternating current delivered to the bridge, such as by varying the average power delivered, and thereby determines the speed at which the armature of the motor 19 rotates.

By the coupling together of the direction selecting switch means and speed selecting resistance means, the first and second controlling means 24, 25 are constructed for particularly advantageous operation by an operator 0. That is, depression of the pushbutton of a controlling means first actuates the direction selecting switch means to energize the desired one of the direction governing relay means 38, 39. Further depression of the corresponding pushbutton adjusts the value of a continuously variable resistor or potentiometer, for smooth and nonincremental variation in the selected speed of movement of the movable member of the crane. Desirably, the further the pushbutton is depressed, the faster the rate of movement of the movable member of the crane.

It is to be particularly noted that such operative interconnection of the electrical circuit elements of the present invention makes efficient use of three conductors through the multiconductor cable 22 for each of the motions controlled. As illustrated in FIG. 5, operatively interconnection between the first and second controlling means 24, 25 there illustrated and the associated circuitry controlling operation of the motor 19 is established through a first signal conductor 60, a second signal conductor 61, and a common conductor 62. Such use of three conductors to accomplish both direction and speed control accomplishes an important advantage of the present invention, by minimizing materials required and by particularly facilitating adaptation of this invention to pre-existing crane structures. More particularly, cranes such as the crane l herein illustrated have been conventionally constructed with three conductors for direction control, without the added benefit of speed control being realized. Such a pre-existing crane may be modified to incorporate the present invention by substitution of manually operable control means 24, 25 as herein disclosed for the direction selecting switches previously employed and by the addition of direction governing relay means and current controlling circuit means as herein disclosed, thereby accomplishing the addition of variable speed control while not requiring replacement of the multiconductor cable previously employed or the trolley conductor arrangements employed to provide electrical interconnection from the carriage 14 to the motor 19 mounted on the transverse beams 16.

In the drawings and specification, there have been set forth preferred embodiments of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

What is claimed is:

1. In a crane having a movable member and drive means including an electrical motor operatively connected to a power source for moving the movable member, the combination therewith of means for controllably varying the direction and speed of movement of the movable member comprising:

first direction controlling electrical switch means,

first speed controlling electrical means,

first manually operable actuator means common to both of said first direction controlling means and said first speed controlling means for coordinated actuation thereof, second direction controlling electrical switch means,

second speed controlling electrical means,

second manually operable actuator means common to both of said second direction controlling means and said second speed controlling means for coordinated actuation thereof, and

means operatively connecting said manually operable controlling means and said drive means for effecting movement of said movable member in a selected one of first and second directions and at a selected speed in response to actuation of a corresponding one of said first and second actuator means, said connecting means including an elongate electrical cable having three conductors respectively electrically connected as a first signal conductor connected with said first direction controlling means, a second signal conductor connected with said second direction controlling means and a common conductor connected with both said direction controlling means, said common conductor and a selected one of said signal conductors transmitting a relatively low voltage direction control signal while said common conductor and the other of said signal conductors transmit a relatively low voltage speed control signal so that said three conductors cooperate with said controlling means for conducting therefrom electrical signals establishing both the direction and the speed of rotation of said electrical motor.

2. The combination according to claim 11 wherein each of said speed controlling means include speed selecting resistance means.

3. The combination according to claim 1 wherein said first and second controlling means are cooperatively interlocked for precluding effective actuation of the other one thereof upon actuation of said corresponding one thereof.

4. The combination according to claim 2 wherein each of said actuator means comprises a depressible pushbutton operatively connected with corresponding ones of said switch means and said resistance means for actuation of said switch means on initial depression thereof and for actuation of said resistance means on further depression thereof.

5. The combination according to claim 2 wherein each of said speed selecting resistance means comprises a continuously variable resistor for smooth and nonincremental variation in the selected speed of movement of said movable member of the crane.

6. The combination according to claim 1 wherein said operative connecting means functions in an electrical circuit and comprises direction governing relay means responsive to said direction controlling means for establishing first and second interconnections with said drive means and thereby for determining the direction of movement in which said movable member of the crane is driven.

7. The combination according to claim 1 wherein said drive means comprises an electrical motor and further wherein said operative connecting means includes current controlling circuit means responsive to said speed controlling means for varying at least one characteristic of alternating current flowing to energize said electrical motor and thereby for determining the speed at which said movable member of the crane is driven.

8. In a crane having at least one movable member and an electrical drive motor for moving said movable member, the combination therewith of means for controllably varying the direction and speed of movement of said movable member and comprising:

direction governing means electrically connected with said drive motor for establishing first and second electrical interconnections therewith and thereby for determining the direction of movement in which said movable member is driven,

speed varying means electrically'connected with a power source, with said direction governing means and thereby with said drive motor for varying at least one characteristic of electrical current flowing thereto from the power source and thereby for determining the speed at which said movable member is driven,

control housing means depending from said crane to within reach of a crane operator for manual handling by the crane operator,

first manually operable direction and speed controlling means mounted within said control housing means for manipulation by the crane operator,

second manually operable direction and speed controlling means mounted within said control housing means for manipulation by the crane operator, and

a multiconductor electrical cable extending between said control housing means and said crane and having a common conductor and first and second signal conductors for establishing electrical interconnection of said direction governing means and said speed varying means with said first and second controlling means and for conducting therebetween relatively low voltage signals establishing both the direction and the speed of said movable member,

said first and second controlling means being operatively interconnected for precluding effective actuation of one of said controlling means during actuation of the other thereof.

t k i i UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 675, 097 D t d July 4, 1972 Inv nt William L. Mulligan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C01; 4, line 58, "Claim 11" should be Claim 1 Signed and sealed this 2L th day of October 1972.

(SEAL) Attest:

EDWARD M.FLET( JHER,JR. ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents FORM PO-1OS0 (10-69) USCOMM-DC 60376-F'69 a uIs. GOVERNMENT PRINTING OFFICE: 1969 o-ass-au UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 675, 097 Dated July 4, 1972 Inventor(s) William L. Mulligan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col.- 4, line 58, "Claim 11" should be Claim 1 Signed and sealed this ZL th day of October 1972.

(SEAL) Attest:

EDWARD M.FLET( JHER,JR. ROBERT GOTTSCHALK Attesting Officer 1 Commissioner of Patents FORM PO-IOSO (10-69) USCOMM-DC 60376-P69 w u.s. GOVERNMENT PRINTING OFFICE: 1969 0-366-334

Claims

1. In a crane having a movable member and drive means including an electrical motor operatively connected to a power source for moving the movable member, the combination therewith of means for controllably varying the direction and speed of movement of the movable member comprising: first direction controlling electrical switch means, first speed controlling electrical means, first manually operable actuator means common to both of said first direction controlling means and said first speed controlling means for coordinated actuation thereof, second direction controlling electrical switch means, second speed controlling electrical means, second manually operable actuator means common to both of said second direction controlling means and said second speed controlling means for coordinated actuation thereof, and means operatively connecting said manually operable controlling means and said drive means for effecting movement of said movable member in a selected one of first and second directions and at a selected speed in response to actuation of a corresponding one of said first and second actuator means, said connecting means including an elongate electrical cable having three conductors respectively electrically connected as a first signal conductor connected with said first direction controlling means, a second signal conductor connected with said second direction controlling means and a common conductor connected with both said direction controlling means, said common conductor and a selected one of said signal conductors transmitting a relatively low voltage direction control signal while said common conductor and the other of said signal conductors transmit a relatively low voltage speed control signal so that said three conductors cooperate with said controlling means for conducting therefrom electrical signals establishing both the direction and the speed of rotation of said electrical motor.

8. In a crane having at least one movable member and an electrical drive motor for moving said movable member, the combination therewith of means for controllably varying the direction and speed of movement of said movable member and comprising: direction governing means electrically connected with said drive motor for establishing first and second electrical interconnections therewith and thereby for determining the direction of movement in which said movable member is driven, speed varying means electrically connected with a power source, with said direction governing means and thereby with said drive motor for varying at least one characteristic of electrical current flowing thereto from the power source and thereby for determining the speed at which said movable member is driven, control housing means depending from said crane to within reach of a crane operator for manual handling by the crane operator, first manually operable direction and speed controlling means mounted within said control housing means for manipulation by the crane operator, second manually operable direction and speed controlling means mounted within said control housing means for manipulation by the crane operator, and a multiconductor electrical cable extending between said control housing means and said crane and having a common conductor and first and second signal conductors for establishing electrical interconnection of said direction governing means and said speed varying means with said first and second controlling means and for conducting therebetween relatively low voltage signals establishing both the direction and the spEed of said movable member, said first and second controlling means being operatively interconnected for precluding effective actuation of one of said controlling means during actuation of the other thereof.