Crane swing safety control

In a braking system having a solenoid operatively associated with the braking mechanism in such a manner that braking is effected unless the coil of said solenoid is energized by being connected to a source of electric power, circuit means selectively to connect said solenoid to said electric source, said circuit means comprising:

• relay means, said relay means having an actuating coil and first and second contacts both of which are normally open, but are closed when the relay of said coil is energized by being connected to said source of electric power;
• a limit switch, said limit switch having a projecting tripping element and said limit switch normally being closed to pass current therethrough unless said projecting tripping element is displaced;
• and
• a temporarily closable switch, said temporarily closable switch having a closing member urged from its closed position but displaceable by manual force to such closed position, and said temporarily closable switch, when not so closed by said member being so displaced, being "open", so that no current may pass therethrough until said closing member is displaced to close said temporarily closable switch,
• one extremity of said relay coil being connected to one terminal of said power source, and the other extremity of said coil being connected to the other terminal of said power source through a series circuit comprising the first contact of said relay means and said limit switch, and through an alternate circuit comprising said temporarily closable switch;
• the second contact of said relay means being interposed between one terminal of said solenoid coil and said source of electric power;
• whereby the brake in said braking system is maintained in braking effect until the member of the temporary closable switch is manually forced into the switch closing position, thereupon to complete a temporary connection of the coil of the relay means to the power source to actuate said relay;
• and upon such actuation, said relay closes both its first and second contacts with the first contact serving to complete the alternate circuit from the power source through the limit switch to the one extremity of the relay coil to maintain said relay coil in energizing position so long as said limit switch remains in its normally closed position;
• and the second contact of said relay means, when so closed, completing a power circuit to the coil of said solenoid, thereby operating said solenoid to release the braking mechanism;
• but said braking mechanism re-effecting braking whenever said projecting yripping element of said limit switch is displaced, thereby to open said limit switch and disconnect the coil of said relay means from said power source to de-energize said relay means and open both said first and second contacts, the opening of said contact breaking the power circuit to the coil of said solenoid.

An electrically operated warning system, said system comprising:

• a. an electrically operated warning device;
• b. a source of electric current;
• c. relay means, said relay means having first and second contacts, said first contact being closed and said second contact normally being open when the coil of said relay means is unenergized by connection to such source of electric current, the disposition of both said contacts being reversed upon the energization of the coil of said relay means;
• and one end of the coil of said relay means being connected to one terminal of said source of electric power;
• d. at least one limit switch;
• and
• e. a temporarily closable switch, said temporarily closable switch having a switch closing member urged from its closed position but displaceable by manual force to said closed position, and said temporarily closable switch, when not so closed by said member, being open so that no current may pass therethrough unless said closing member is displaced temporarily to close said temporarily closable switch;
• the other end of the coil of said relay means being connected to the other terminal of said power source through a series circuit comprising the second contact of said relay means and said limit switch and through an alternate circuit comprising said temporarily closable switch;
• the first contact of said relay means being interposed between one terminal of said warning device and said source of electric power, the other terminal of said warning device being connected to said source of electric power, whereby said warning device will be activated until said closing member of said temporarily closable switch is displaced by manual force to the closed position of said switch, thereby temporarily completing the alternate circuit between the other end of the coil of the relay means and the other terminal of the power source to energize the coil of the relay means and reverse the closed and open dispositions respectively of said first and second contacts, the opening of the first contact causing said warning device to become deactivated, and the closing of the second contact serving to complete a circuit between the other end of said coil of said relay means to the power source through said limit switch, and to maintain such energization until the projecting tripping element of said limit switch is displaced to open said limit switch and thereupon break the circuit between said other terminal of the power source and the other end of the coil of said relay means, and thereby de-energize the same, whereupon the first contact of said relay means is reclosed to activate said warning device.

Means to limit the angular rotation of the rotatable turret of a crane about a cylindrical post fixedly mounted on the platform on which the turret of the crane is carried, to prevent the crane boom from too closely approaching high-tension wires or other structure, wherein the crane turret is provided with a brake band circumscribing said post, said brake band being urged by spring means into a first position in which said brake is tightened about said post to block relative rotation between said turret and said cylinder, said brake band being releasable by action of a piston in a hydraulic cylinder, in opposition to the urging of said spring, moving said spring into a second position wherein said brake band is sufficiently loosened about said post to permit such relative rotation, the action of said piston in said cylinder being manually controllable by operating control means located in the crane cab, said control means being operable either to permit fluid under pressure from a source of supply thereof to be conducted to said cylinder to drive the piston therein, or alternatively, to cut off the supply of said fluid to said cylinder and to cause the fluid under pressure in said cylinder to be discharged therefrom, said limiting means comprising:

• a. override valve means, said valve means being interposable between the supply of fluid under pressure and said hydraulic cylinder, said value means being shiftable between a first position wherein communication is maintained through said control means between said supply of fluid under pressure and said cylinder, and a second position wherein such communication is cut off and the fluid in the cylinder is discharged therefrom;
• b. a solenoid operatively associated with said valve means, said solenoid, when actuated by an electric current being conducted through the coil of said solenoid, serving to shift said valve means from its said second position to its said first position;
• c. a source of electric current connectable to said solenoid to actuate the same;
• d. switching means disposed peripherally about the crane turret to rotate therewith, said switching means being switched to and maintained in an "on" position, and said switching means when so switched to its "on" position, serving to connect said source of current to the coil of said solenoid to actuate the latter, said switching means including an arm which, when struck by an inwardly projecting element, turns the switching means from its "on" position to its "off" position;
• and
• e. projecting means to operate said switching means to swtich it from its "on" position to its "off" position;
• said projecting means being disposable fixedly adjacent the periphery of said crane turret and at a predetermined point on and within the arc of swing of said switching means on said crane turret, said projecting means comprising a threaded element passed upwardly through a slot in an elongated channel member and held at a predetermined position in said slot by a nut;
• and said channel member being securable on said platform at predetermined positions circumscribing said turret and spaced from each other by the length of said slot, by means of removable fastners extending downwardly into orifices in said platform whereby said upwardly projecting threaded element may be disposed securely at any point in a complete circle circumscribing said turret to trigger said switching means, whereby when said turret is rotated to cause said switching means to pass and strike said projecting means, said switching means will be switched from its "on" position to its "off" position, thereby causing said solenoid to cease maintaining said valve means in its first position and to shift said valve means from its said first position and to its said second position, with the result that said brake band is urged back by its spring to its first position of tightening about said post, to prevent further relative rotation between said turret and said fixed post.

Means to limit the angular rotation of the rotatable turret of a crane about a cylindrical post fixedly mounted on the platform on which the turret of the crane is carried, to prevent the crane boom from to closely approaching high-tension wires or other structure, wherein the crane turret is provided with a brake band circumscribing said post, said brake band being urged by spring means into a first position in which said brake band is tightened about said post to block relative rotation between said turret and said cylinder, said brake band being releasable by action of a piston in a hydraulic cylinder, in opposition to the urging of said spring, moving said spring into a second position wherein said brake band is sufficiently loosened about said post to permit such relative rotation, the action of said piston in said cylinder being manually controllable by operating control means located in the crane cab, said control means being operable either to permit fluid under pressure from a source of supply thereof to be conducted to said cylinder to drive the piston therein, or alternatively, to cut off the supply of said fluid to said cylinder and to cause the fluid under pressure in said cylinder to be discharged therefrom, said limiting means comprising:

• a. override valve means, said valve means being interposable between the supply of fluid under pressure and said hydraulic cylinder, said valve means being shiftable between a first position wherein communication is maintained through said control means between said supply of fluid under pressure and said cylinder, and a second position wherein such communication is cut off and the fluid in the cylinder is discharged therefrom;
• b. a solenoid operatively associated with said valve means, said solenoid, when actuated by an electric current being conducted through the coil of said solenoid, serving to shift said valve means from its said second position to its said first position;
• c. a source of electric current connectable to said solenoid to actuate the same;
• d. switching means disposed peripherally about the crane turret to rotate therewith, said switching means being switched to and maintained in an "on" position, and said switching means when so switched to its "on" position, serving to connect said source of current to the coil of said solenoid to actuate the latter, said switching means including an arm which, when struck by an upwardly projecting element, turns the switching means from its "on" position to its "off" position;
• and
• e. projecting means to operate said switching means to switch it from its "on" position to its "off" position;
• said projecting means being disposable fixedly adjacent the periphery of said crane turret and at a predetermined point on and within the arc of swing of said switching means on said crane turret, said projecting means comprising a threaded element passed upwardly through a slot in an elongated channel member and held at a predetermined position in said slot by a nut, and said channel member being securable on said platform about the arc of swing of said turret, whereby when said turret is rotated to cause said switching means to pass and stike said projecting means, said switching means will be switched from its "on" position to its "off" position, thereby causing said solenoid to cease maintaining said valve means in its first postition and to shift said valve means from its said first position to its said second position, with the result that said brake band is urged back by its spring to its first position of tightening about said post, to prevent further relative rotation between said turret and said fixed post.

Means to limit the angular rotation of the rotatable turret of a crane about a cylindrical post fixedly mounted on the platform on which the turret of the crane is carried, to prevent the crane boom from too closely approaching high-tension wires or other structure, wherein the crane turret is provided with a brake band circumscribing said post, said brake band being urged by spring means into a first position in which said brake band is tightened about said post to block relative rotation between said turret and said cylinder, said brake band being releaseable by action of a piston in a hydraulic cylinder, in opposition to the urging of said spring, moving said spring into a second position wherein said brake band is sufficiently loosened about said post to permit such relative rotation, the action of said piston in said cylinder being manually controllable by operating control means located in the crane cab, said control means being operable either to permit fluid under pressure from a source of supply thereof to be conducted to said cylinder to drive the piston therein, or alternatively, to cut off the supply of said fluid to said cylinder and to cause the fluid under pressure in said cylinder to be discharged therefrom, said limiting means comprising;

• a. override valve means, said valve means being interposable between the supply of fluid under pressure and said hydraulic cylinder, said valve means being shiftable between a first position wherein communication is maintained through said control means between said supply of fluid under pressure and said cylinder, and a second position wherein such communication is cut off and the fluid in the cylinder is discharged therefrom;
• b. a solenoid operatively associated with said valve means, said solenoid, when actuated by an electric current being conducted through the coil of said solenoid, serving to shift said valve means from its said second position to its said first position;
• c. a source of electric current connectable to said solenoid to actuate the same;
• d. switching means disposed peripherally about the crane turret to rotate therewith, said switching means being switched to and maintained in an "on" position, and said switching means when so switched to its "on" position, serving to connect said source of current to the coil of said solenoid to actuate the latter;
• e. projecting means to operate said switching means to switch it from its "on" positon to its "off" position;
• said projecting means being disposable fixedly adjacent the periphery of said crane turret and a predetermined point on and within the arc of swing of said switching means on said crane turret, whereby when said turret is rotated to cause said switching means to pass and strike said projecting means, said switching means will be switched from its "on" position to its "off" position, thereby causing said solenoid to cease maintaining said valve means in its first position and to shift said valve means from its said first position to its said second position, with the result that said brake band is urged back by its spring to its first position of tightening about said post, to prevent further relative rotation between said turret and said fixed post;
• and
• f. additional valve means and conduits whereby said override valve means may, at the option of the crane operator, either be bypassed all together to permit the hydraulic braking system of the turret to be controlled entirely by the crane operator, or interposed between the hydraulic cylinder and, through the operators manual control means, the supply of pressure fluid, to provide a safety override valve control.

Means to limit the angular rotation of the rotatable turret of a crane about a cylindrical post fixedly mounted on the platform on which the turret of the crane is carried, to prevent the crane boom from too closely approaching high-tension wires or other structure, wherein the crane turret is provided with a brake band circumscribing said post, said brake band being urged by spring means into a first position in which said brake band is tightened about said post to block relative rotation between said turret and said cylinder, said brake band being releasable by action of a piston in a hydraulic cylinder, in opposition to the urging of said spring, moving said spring into a second position wherein said brake band is sufficiently loosened about said post to permit such relative rotation, the action of said piston in said cylinder being manually controllable by operating control means located in the crane cab, said control means being operable either to permit fluid under pressure from a source of supply thereof to be conducted to said cylinder to drive the piston therein, or alternatively, to cut off the supply of said fluid to said cylinder and to cause the fluid under pressure in said cylinder to be discharged therefrom, said limiting means comprising:

• a. override valve means, said valve means being interposable between the supply of fluid under pressure and said hydraulic cylinder, said valve means being shiftable between a first position wherein communication is maintained through said control means between said supply of fluid under pressure and said cylinder, and a second position wherein such communication is cut off and the fluid in the cylinder is discharged therefrom;
• b. a solenoid operatively associated with said valve means, said solenoid, when actuated by an electric current being conducted through the coil of said solenoid, serving to shift said valve means from its said second position to its said first position;
• c. a source of electric current connectable to said solenoid to actuate the same;
• d. switching means disposed peripherally about the crane turret to rotate therewith, said switching means being switched to and maintained in an "on" position, and said switching means when so switched to its "on" positon, serving to connect said source of current to the coil of said solenoid to actuate the latter;
• and
• e. projecting means to opearte said switching means to switch it from its "on" position to its "off" position;
• said projecting means being disposable fixedly adjacent the periphery of said crane turret and at a predetermined point on and within the arc of swing of said switching means on said crane turret, said projecting means comprising member, said channel member being secured adjacent the periphery of the crane turret and within the arch of swing of said switching on said crane turret, said channel member being slotted for at least a substantial part of its length and having fastner means projecting through said slotting and fixedly securable at any predetermined point along the length of said slotting, whereby when said turret is rotated to cause said switching means to pass and strike said projecting means, said switching means will be switched from its "on" position to its "off" position, thereby causing said solenoid to cease maintaining said valve means in its first position and to shift said valve means from its said first position to its said second position, with the result that said brake band is urged back by its spring to its first position of tightening about said post, to prevent further relative rotation between said turret and said fixed post.

A warning and braking system comprising;

• a. means to limit the angular rotation of the rotatable turret of a crane about a cylindrical post fixedly mounted on the platform on which the turret of the crane is carried, to prevent the crane boom from too closely approaching high-tension wires or other stucture, wherein the crane turret is provided with a brake band circumscribing said post, said brake band being urged by spring means into a first position in which said brake band is tightened about said post to block relative rotation between said turret and said cylinder, said brake band being releasable by action of a piston in a hydraulic cylinder, in opposition to the urging of said spring, moving said spring into a second position wherein said brake band is sufficiently loosened about said post to permit such relative rotation, the action of said piston in said cylinder being manually controllable by operating control means located in the crane cab, said control means being operable either to permit fluid under pressure from a source of supply thereof to be conducted to said cylinder to drive the piston therein, or alternatively, to cut off the supply of said fluid to said cylinder and to cause the fluid under pressure in said cylinder to be discharged therefrom, said limiting means comprising;
• i. override valve means, said valve means being interposable between the supply of fluid under pressure and said hydraulic cylinder, said valve means being shiftable between a first position wherein communication is maintained through said control means between said supply of fluid under pressure and said cylinder, and a second position wherein such communciation is cut off and the fluid in the cylinder is discharged therefrom;
• ii. a solenoid operatively associated with said valve means, said solenoid, when actuated by an electric current being conducted through the coil of said solenoid, serving to shift said valve means from its said second position to its said first position;
• iii. a source of electric current connectable to said solenoid to actuate the same;
• iv. switching means disposed peripherally about the crane turret to rotate therewith, said switching means being switched to and maintained in an "on" position, and said switching means when so switched to its "on" position, serving to connect said source of current to the coil of said solenoid to actuate the latter;
• v. projecting means to operate said switching means to switch it from its "on" position to its "off" position;
• said projecting means being disposable fixedly adjacent the periphery of said crane turret and at a predetermined point on and within the arc of swing of said switching means on said crane turret, whereby when said turret is rotated to cause said switching means to pass and strike said projecting means, said switching means will be switched from its "on" position to its "off" position, thereby causing said solenoid to cease maintaining said valve means in its first position and to shift said valve means from its said first position to its said second position, with the result that said brake band is urged back by its spring to its first position of tightening about said post, to prevent further relative rotation between said turret and said fixed post;
• and
• b. means to warn a crane operator of his attaining the limit of a permissable angular rotation of said rotatable turret of the crane on the platform on which said turret of the crane is carried, said means comprising;
• i. an electrically operable alarm device;
• ii. a source of electrical current;
• iii. an electrically operated relay, said relay being connectable to said source of electrical current and having a first contact in circuit with said source of electric current and said alarm device and said contact being noramlly closed to activate the alarm device;
• said relay having a second contact and circuit with the source of electric current and with the energizing coil of said relay and normally maintained in open circuit breaking position;
• said relay, when actuated, opening the first contact and closing the second contact;
• said switching means being in series with said second contact and, when switched to its "off" position, serving to open the relay circuit and thereby close the said first contact to operate said alarm device;
• iv. second switching means serving momentarily to connect said source of electric current to said relay to actuate the latter, and thereby open the first contact and close the second contact;
• v. said projecting means when passed and struck by the switching means serving to switch the latter switching means from its "on" position to its "off" position, thereby breaking the relay circuit with said source to electric power to denergize said relay, and cause said second contact to close and operate said alarm device.