US3885676A

US3885676A - Crane system for cargo containers

Info

Publication number: US3885676A
Application number: US352876A
Authority: US
Inventors: Lester W Wilson; Joseph H Tracy; Clarence C Wilson
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-04-20
Filing date: 1973-04-20
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27

Abstract

A container head, supported by cables via a spreader bar, is provided with locking devices at the four corners for engaging a cargo container. When the container head is in place on a container, the container can be engaged or disengaged with respect thereto, but the locking devices cannot be operated when the container head is not in place, e.g., when the container head is performing a lifting function. Guides, located at the sides and ends of the container head, as well as tag motors for ''''reining'''' the container head, assist a crane operator in positioning the head on a container.

Description

United States Patent 1 Wilson et a1.

[ 1 CRANE SYSTEM FOR CARGO CONTAINERS [75] Inventors: Lester W. Wilson, Portland; Joseph H. Tracy, Troutdale', Clarence C. Wilson, Portland, all of Greg.

[73] Assignees: Lester W. Wilson; Clarence C.

Wilson, both of Portland, Oreg.

[22] Filed: Apr. 20, 1973 [21] Appl. No.: 352,876

Wyrough 294/67 DA 3,378,158 4/1968 Lopez 254/172 3,501,193 3/1970 Gray 294/67 R 3,520,431 7/1970 Tax 294/67 R Primary ExaminerEvon C. Blunk Assistant Examiner-Jeffrey V. Nase Attorney, Agent, or Firm-Klarquist, Sparkman, Campbell, Leigh, Hall & Whinston [57] ABSTRACT A container head, supported by cables via a spreader bar, is provided with locking devices at the four corners for engaging a cargo container. When the container head is in place on a container, the container can be engaged or disengaged with respect thereto, but the locking devices cannot be operated when the container head is not in place, e.g., when the container head is performing a lifting function. Guides, located at the sides and ends of the container head, as well as tag motors for reining" the container head, assist a crane operator in positioning the head on a container.

11 Claims, 11 Drawing Figures PATENTEU 3 885 676 SHEET 2 FIG. 3 f

SHEET FIG. ID

THE

AIR SUPPLY FIG. 8

IZZdK 1 22b I D m I c w w m Gr V ZVM 1\ D 0 m 9 C o L N u a 2 2 CRANE SYSTEM FOR CARGO CONTAINERS BACKGROUND OF THE INVENTION This invention relates to a crane system for cargo containers and particularly to a system which facilitates rapid loading and unloading of the containers in a safe manner.

Cargo containers have recently become popular for facilitating the rapid loading and unloading of ship car goes to or from trailer-trucks and railroad cars. For example, a cargo container may be transported on a truck body to dockside where the same may be hoisted as a unit into the hold of an awaiting ship. However, some difficulty is experienced in accurately guiding these rel atively massive loads from a crane. in moving the same into position. Also. container heads," heretofore employed for engaging the containers, have themselves been heavy in structure for enabling these heads to carry the weight of a container. Furthermore, the loading or unloading of cargo is difficult and dangerous when the crane operator cannot actually see when the container is being engaged or disengaged, even though manual assistance may be provided. A particularly dangerous situation arises when it is believed a container is fully down and positioned inside a ships hold, when, as a matter of fact. one or more corners of the container are not fully supported from underneath. When the container head is then remotely unlocked for releasing the container, the heavy container may be inadvertently dropped some undetermined distance, or may even tip to one side, resulting in costly damage and extreme danger to personnel. These factors tend to decrease the speed with which the loading or unloading operation might otherwise be performed.

SUMMARY OF THE INVENTION According to the present invention, a crane system for cargo containers includes a container head adapted to be received upon the top of a container, the container head being provided with a plurality of remotely operated locking members for engaging a plurality of matching locking devices provided at the top of the container. Cable means suspend the container head from a crane boom, and means are responsive to the tension in said cable means for preventing unlocking of the said locking members in the presence of tension in the cable means.

In a preferred embodiment, the means responsive to tension in the cable means for preventing unlocking of the locking members includes plural pressure-sensitive switching devices operative, when the weight of the container head is not resting on the container. for inhibiting unlocking operations of the locking members.

According to an embodiment of the present invention, the cable means includes a spreader bar posi tioned between the crane boom and the container head for more adequately supporting the container head and container at the corners thereof to reduce the size and weight of the container head structural members.

The system according to the present invention also desirably includes a plurality of hingeable guides located on the container head and adapted to be rotated into a position extending downwardly from the container head. These guides are supported in their down ward position with bracing means for taking the thrust of lateral forces when the guides encounter the side of a container.

According to the preferred embodiment of the present invention, the crane system includes tag motors for operating tag lines via air-operated clutches for guiding or reining' a container head and container into a de' sired position or orientation.

It is accordingly an ()hJCCl of the present invention to provide an improved crane system for cargo containers which expedites the handling of such containers while maintaining safety with respect to property and personnel.

It is a further object of the present invention to provide an improved crane system for cargo containers wherein the crane system operator is in maximum con trol of container movement despite visual difficulties encountered when the container is in a ships hold or the like.

It is another object of the present invention to provide an improved crane system for cargo containers enabling use of a container head of comparatively light construction.

It is another object of the present invention to provide a crane system for cargo containers which is safe in its operation.

It is another object of the present invention to provide a crane system for cargo containers facilitating the rapid and safe movement of a container head onto and away from a container.

The subject matter which we regard as our invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, both as to organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with the ac companying drawings wherein like reference characters refer to like elements.

DRAWINGS FIG. 1 is a side view of a crane system according to the present invention;

FIG. 2 is an elevational view of a spreader bar according to the present invention, said view being taken at 2-2 in FIG. 1;

FIG. 2A is a cross section of the FIG. 2 spreader bar taken at 2A2A in FIG. 2;

FIG. 3 is a top view, partially broken away, of a por tion of the crane system according to the present invention including tag motors and a mounting platform therefor, FIG. 3 being taken at 3-3 in FIG. 1'.

FIG. 4 is a top view, partially broken away, of a container head according to the present invention, FIG. 4 being taken at 4-4 in FIG. 1;

FIG. 5 is a side elevational view, partially broken away, of the FIG. 4 container head;

FIG. 6 is a partially broken away cross-sectional detail of a locking device positioned at a corner of the FIG. 4 container head and including a switching device 106 according to the present invention. FIG. 6 being taken at 6-6 in FIG. 4',

FIG. 7 is a partially broken away cross-sectional view of a hingeable guide employed according to the present invention, this view being taken at 7-7 in FIG. 4;

FIG. 8 is a schematic diagram of electrical control circuitry according to the present invention.

FIG. 9 is a diagram of a hydraulic system according to the present invention; and

FIG. is a diagram of a pneumatic system according to the present invention.

DETAILED DESCRIPTION Referring to the drawings and particularly to FIG. I, a container cargo system according to the present invention includes a conventional crane 10 including a boom 12 supporting cable means 14 carrying blocks 16. The crane is conventionally a two-drum crane having a pair of cable systems in side-by-side relation for simultaneously lifting both ends of a load, only one cable system being illustrated in the side view of FIG. 1. The hooks 18 of blocks 16 support a spreader bar 20 more fully illustrated in FIGS. 2 and 2A, the spreader bar comprising a central pipe member 22 having a pair of upper ears 24 supported from hooks 18 via intervening shackle members 26. Lower ears 28 welded to pipe member 22 are provided with side plates 30 disposed in spaced relation on either side of cars 28 for supporting sheaves 32 over which side cables 34 extend, there being four pairs of such side cables attached in supporting relation to four corners of container head 36 in FIG. 1. The spreader bar 20 is actually proportionately much longer than is depicted for the sake of convenience in FIG. 2, and in a particular instance is approximately 7 feet long. The spreader bar 20, placed

intermediate cables

14 and 34, maintains a nearly in-line condition between the same, or an angle of nearly 180, while spreading the cables for optimum support of container head 36. By means of this arrangement. the container head is adequately supported at the corners thereof, at which points the container itself is supported, whereby the structural construction of the container head need not be as heavy or cumbersome as in the case of prior container heads. Container head 36 supports an electrical cable holder 38 receiving electrical cable 40 in coiled relation therewithin. Cable 40, which provides for remote operation of container head functions, is ultimately connected to the cab of the crane by means not shown.

The crane 10 is further provided with a forward platform 42 as illustrated in FIG. 3 upon which tag motors 44 are located. These tag motors include electrical drive motors 46 and a pneumatically operated clutch 48 through which chain drive 50 rotates cable reels 52 about which tag cables 54 are wrapped. The tag cables 54 respectively pass over sheaves 56 mounted on either end of a tag cable bar 58, and from thence the tag cables pass down to spaced locations on the front side container head 36 where the same are attached. Only one cable 54 is shown in FIG. 5, illustrating the container head, since the view is broken away, but the remaining cable 54 is suitably connected to the container head at a location symmetrically spaced at the opposite side of the container heads center line. The crane operator is provided with an air valve 60 for operating each tag motor clutch, such air valve being coupled to an air supply 62 as illustrated in FIG. 10. By means of operation of a pair of valves 60, the clutches 48 may be individually operated while motors 46 continuously run whereby to control the tension in cables 54. It will be seen that differential pressure on clutches 48 can be used for "reining" the cables 54 whereby to guide and angularly position the container head 36. Accordingly, the tag motors are not only useful in guiding the container head to and from a container, but are also useful in guiding and positioning a container when supported by the container head.

In the particular instance illustrated in FIG. I, the container head 36 is positioned on top of a container disposed on a truck trailer 72 which supplies a sup porting surface for the container 70. The hold of a ship or the deck of a pier can also supply a supporting surface. The container head system may be employed for lifting the container 70 from the truck trailer and placing the same in the hold of a cargo ship, or vice versa, but in either case the present system provides the desired control and positioning required for these maneuvers.

The container head 36 further includes hingeable guides 74 which may be rotated downwardly into the position illustrated in FIG. 1 to guide the container head 36 onto container 70. In the illustrated view, two of the guides shown are lowered and one, numbered 74', is illustrated in upraised position, which is the typical manner in which the guides will be employed in approaching the container 70 from the left and from the position of the viewer in FIG. 1. In addition, a further side guide will be in lowered position on the left-hand side of container 70, while two right-hand guides and a guide at the rear of the container 70 will be in upraised position. When the container head 36 is finally disposed in proper position on a container 70, locking members as hereinafter more fully described are operated to engage locking sockets provided in the container at the four corners thereof.

Referring now to FIGS. 4 and 5 illustrating the container head 36 in greater detail, the container head comprises side beams 76, and end beams 78 joined thereto, for completing a rectangular configuration generally matching the top dimensions of the standard cargo container. The container head is provided with various side bracing members 80 and is also provided with a locking device 82 disposed at each corner thereof for engaging the container. As illustrated, the cables are attached to gusset members 84 secured to the corners of the structure proximate the location of locking devices 82. The container head is also provided with indicating means 86', 88' and 90' comprising indicating lamps as hereinafter more fully described, and the container head also supplies support for hydraulic cylinders as hereinafter more fully described as well as a reservoir of hydraulic fluid, pumping means, valving means, and the like by means of which the hydraulic cylinders are controlled.

Referring now to FIG. 6 illustrating a locking device 82 in greater detail, the said device is enclosed in a box structure 92 at a corner of the container head 36 which includes a sleeve 68 journaling a locking shaft 94 at the lower end of which is a locking male member 96 adapted to engage a slot in a female receptacle or socket 98 located at a corner of the container 70. Both the slot and member 96 are elongated such that the member 96 may enter the slot and then be rotated by 90 for engaging the underside of the receptacle for supporting the container 70. The shaft 94 is rotated by actuating rod 100 ofhydraulic cylinder 102 the remaining end of which is pivotally attached to plate welded to a side beam 78 of the container head 36. The actuating rod 100 is pivotally connected to a crank 104 which is unitary with a supporting collar 66 secured to shaft 94 whereby extension of actuating rod 100 rotates locking member 96 into the locking position as is illustrated in the drawing. Stop 64, also secured to collar 66, limits rotation of the locking member to its correct locking position when stop 64 strikes gusset 84.

The container head is provided with tension detecting means at the four corners thereof for ascertaining when the cable system comprising cables 34 is under tension, and when the same is slack indicating the container is no longer being lifted or supported by the cables. In the illustrated embodiment, the tension detecting means comprises a pressure sensitive switching device 106 disposed at the underside of each corner of container head 36. This switching device comprises a plate 108 which is provided with a pivotal connection 110 for pivotally supporting the same from an underplate 112 secured at the bottom of box structure 92 of the container head structure. The plate 98 also includes an inverted L-shaped upward extension 114 apertured to receive a threaded switch actuating rod 116 of a switch 118 secured to a wall of box structure 92. The rod 116 extends through the aperture in the upper leg of the L-shaped extension 114 and is provided with adjusting nuts such that hingeable movement of plate 108 operates the switch. The remote end of L-shaped extension 114 is attached by a spring 120 to the upper part of beam 78 whereby the plate 108 is normally biased in a downward position indicated by dashed lines in the drawing. At this time switch 118, provided with normally open contacts, affords no electrical connection in the circuit in which it is disposed. However, when the container head is located on the container as illustrated in FIG. 6, plate 108 pivots counterclockwise to the position shown in full line in FIG. 6 against the bias of spring 120, and the normally open contacts of switch 118 become closed.

As hereinafter more fully described, a locking device 82 may be operated only when closing of the contacts of switch 118 indicates the container head is resting on container 70. If the container head has neither engaged a container at all, or if the container head is lifting a container such that the top of member 96 engages the underside of the top of socket 98, then the switch plate 108 will be in its clockwise position, opening contacts 118. Thus, closing of the contacts of switch 118 indicates a slackness in the cables 34 lifting the container head. FIG. 6 shows the relative position of the different parts when the sling 34 is fully slack, and the crane is not supplying any lift. Under these conditions, provided the container head is properly seated on the container sockets 98, the underplates 112 of the container head rest on plates 108, which rest on the tops of sockets 98. Under this condition, and only under this condition, are the switches 118 closed. When the sling 34 is tensioned, the container head lifts slightly till locking male members 96 engage the under-abutting surfaces of sockets 98. The small upward movement of the container head permits underplates 108 to move towards the dotted position shown in FIG. 6, thereby opening switches 118. Thus, switches 118 are closed only when the container head is fully down on the sockets 98 of the container, and, when hoisting begins, the initial tensioning of the sling 34 immediately opens the switches 118, even before the crane takes enough strain to lift the container 70 off its supporting surface, such as truck trailer 72. As hereinafter more fully described, contacts of switches 118 disposed at the four corners of the container head are connected in series, and all four sets of contacts must be closed in order to operate the locking device 82 either from a locked to an un' locked position, or from an unlocked to a locked position. Hydraulic cylinder 102 is also provided with a switching device 122 conveniently mounted on a gusset member 84, the switching device being operated by a collar 123 on actuating rod to indicate when the actuating rod 100 is extended. When the actuating rods corresponding to all switches 122 are extended, i.e., when the locking members 96 at all four corners engage the sockets 98 of a container in locking relation, an indiction is given to the operator.

FIG. 7 illustrates a guide 74 in greater detail. Guide 74 comprises a guide arm or first arm 124 which is pivotally engaged at 126 to the upper part of a hook struc ture 128 joined to one of the beams, i.e., beam 78, forming a part of a main structure of the container head. The up" position for the guide is shown in full line, and the down" position in dashed line. The guide arm 124 has nearly the shape of a \V" including a straight portion 130 adapted to engage the side of container 70 when the arm is in lowered position, and a bent-out portion 131 extending therebelow. Above the location of the side of the container, the guide arm 124 includes a section 132 extending back to a pivot pin 134 adapted to be downwardly received in the up wardly facing opening 136 of hook structure 128. The remainder of arm 124 extends to pivot 126.

A second arm 138 is connected to arm 124 by pivot pin 134 and arm 138 is in turn pivotally connected to a third upwardly extended arm 140 having the shape of an inverted V when arm 124 is in its downward or dashed line position. The remaining end of third arm 140 is pivotally joined to a plate 142 secured to the structure of container head 36. The apex of the V is pivotally joined to the actuating rod 144 of a hydraulic cylinder 146, the remaining end of which is connected to a plate 148 by means of a pin 150. The plate 148 is welded to the container head,

When not in use, the guide 74 is maintained with guide arm 124 in the upraised position. When it is desired to lower the same, cylinder 146 is actuated to move rod 144 outwardly in a direction to the left in FIG. 7 which in turn rotates third arm 140, second arm 138 and first arm 124 in a counterclockwise direction. The pivot pin 134 is received within the opening 136 of hook structure 128, the pivot pin 134 moving downwardly into the opening by means of the linkage provided. When it is desired to move the first arm 124 to its original position, the hydraulic cylinder 146 is operated in its reverse direction for easily moving the arm 124 upwardly. However, it will be realized that during the course of moving the container head relative to a container while maintaining a group of arms 124 in their downward position, the arms 124 will encounter the container by striking the same. According to the illustrated device, the force upon the arm 24 will be sideways, i.e., to the left in FIG. 7 against the downwardly extended arm 124. The force is received by the lefthand side of the hook opening 136 by the hook structure 128 to prevent damage to the linkage and to the cylinder 146 as would prevent operation of the device.

Normally, the guides 74 are used by threes. That is, the arms on one side and one end of the container head will be lowered, while the arms on the remaining side and end will be upraised, while the container head is moved towards the container until the side and end with the lowered arms encounter the container whereby the container head can be guided onto the container. As the container head is correctly positioned. the same 1\ moved downwardly \vlicrcbv the locking members 96 become inserted in sockets )8. Then the locking devices 82 are operated, assuming pressure sensitive switching devices 106 all indicate the container head is firmly in place The container 111d then be lifted by means of the container head and crane to the desired location. The locking devices 82 may not be unlocked until the container is relocated on the lirin ba e and the sv itching devices 106 again indicate slackness in the cables as the container head rests upon the container Therefore the cylinders 102 may be op eratcd For unlocking the devices 82 at this time, after which the container head may be safely upraised.

FIGS. 8 and 9 will now he considered, these figures respectively illustrating electrical and hydraulic diagrams according to the present invention. The electrical control diagram of FIG. 8 includes connections 152 and 154 to a source of control voltage. The switches 118 at the four corners of the container head are connected in series as indicated at 118a, 118b, 1180, and 118d, such series circuit being connected between line 154 and operator's lamp 86 in the cab of the crane, which indicates when the four corners of the container are down, i.e., lines 34 are slack. In addition, an amber lamp 86 in parallel with lamp 86 and located on the container head is illuminated at this time for indicating to workers in the vicinity when the corners are fully down. Lamps 86 and 86' are returned to line 152. Further in parallel with the

lamps

86 and 86 are relay operating coils R1 and R2 which operate contacts R1 and R2, respectively in series with lock and unlock

solenoids

156 and 158. Lock solenoid 156 is disposed between line 152, and the series connection of contacts R1 and the normally open contacts of a double throw switch 160 returned to the remaining line 154. Unlock solenoid 158 is disposed between line 152, and the series connection of contacts R2 and the normally closed contacts of switch 160, returned to line 154. Switch 160 is a lock-unlock control switch located in the operator's cab of the crane.

Solenoids

156 and 158 operate valve 162 in FIG. 9 between lock and unlock positions for operating the hydraulic cylinders 102 between lock and unlock positions. Hydraulic fluid is delivered via

lines

163 and 166 for operating cylinders 102 for respectively locking and unlocking the devices 82. Hydraulic fluid is pumped by pump P from reservoir R to the valve, and hydraulic fluid is returned from the valve to the reservoir. The hydraulic system elements are all suitably mounted on the container head and remotely operated electrically as described herein. When the crane lowers the container head fully upon a container, all of the

switches

118a, 118b, 118C. and 1184 should close. and lamps 86 and 86' will light. At this time. contacts R1 and R2 will close permitting the operator to operate lock solenoid 156 by throwing switch 160 to the left. However, if all the corners are not down. the series circuit through

switches

118a, 118/1, 118e, and 118d will be broken, control coil R1 will fail to operate contacts R1, and consequently the corners of the container head cannot be changed from an unlocked to a locked condition. Assuming, however, that the corners of the container head are locked in place, it will be seen that the same cannot be unlocked until the lines are slack as detected once again by clo sure of

switches

118a, 118b, 118e, and 118d Thus,

Ltitttttcts R2 t lll remain open and despite the operators throwinc witch 160 from the left hand position to the right It ind position. the container head will remain locked to the container. This prevents unloading the container or dropping a part of the container when some or all of the corners of the container are not in place and the actual position of the container may not lie observable by the crane operator.

The switches associated with the respective locking cylinders 102 are indicated at 122a, 122b, 122C, and 1221! in FIG 8. The switches are disposed in series between line 154 and the parallel combination of lamps and 90' returned to line 152. The lamp 90 is in the operators cab, and lamp 90' is disposed on the con tamer head. Thus, the operator as well as other workers in the vicinity can be assured that the container head is locked in place.

A pressure switch 164 is disposed in series between line 154 and the parallel combination of lamps 88 and 88' connected in parallel between switch 164 and line 152. Switch 164 is illustrated in FIG. 9 and is a switch indicating the pressure in unlock line 166 which operates cylindcrs 102 to an unlocked position. During unlocking, all the cylinders 102 must be returned to an unlocked position before sufficient pressure builds up in line 166 for operating switch 164. Returning to FIG. 8, an operators switch 168 in the crane operators cab is connected in series with near side arm solenoid 170 between lines 152 and 154, while an operator's switch 172 also in the operators cab is disposed in series with far side solenoid 174 between lines 152 and 154. Near side solenoid 170 operates hydraulic valve 176 in FIG. 9 for providing hydraulic fluid to a trio of cylinders 146 associated with guide 74 on one side and one end of the container head. Similarly, solenoid 174 operates hydraulic valve 178 in FIG. 9 lowering the arms 124 associated with the remaining three guides 74 on the container head. Each of the

valves

176 and 178 is of the automatic return variety whereby when the

respective switches

168 and 172 are opened, the corresponding arms 124 will upraisc by reversing the flow of hydraulic fluid to the respective cylinders 146.

Returning again to FIG. 8, lamp 86' and corners down lamp 86 are conveniently amber colored lights, locked" lamps 90 and 90' are conveniently green colored lights, and unlocked" lamp 88 and lamp 88 are conveniently red colored lights. Then, at the beginning of ordinary operation, the container head will be unlocked and free of a container whereby the red lights will be illuminated. The operator may guide the container head into the proper position through manipulation of the crane and the tag motor clutches, with an appropriate one of

switches

168 and 172 closed to lower guide arms on the side and end of the container head farthest from the container. When the container head is guided into place and fully lowered onto a container, and all four corners are in place but not locked. the

amber lamps

86 and 86 will light indicating to the operator that he may lock the container head in place. Switch may be thrown from the right-hand position to the left-hand position causing the locks to operate, turning on green lamps 90 and 90' and turning off red lamps 88 and 88'. Now the load may be raised with the crane causing the amber lamps 86 and 86' to go out as the weight of the container is borne by the container head rather than vice versa. The corner locks cannot be unlocked at this time. When the load is deposited in place and fully supported from underneath, the amber lights 86 and 86' become illuminated and the switch 160 can be effectively thrown from the left-hand position to the right-hand position causing unlocking of the corners of the container head. At this time, the

red lamps

88 and 88 are illuminated once again and green lamps 90 and 90' go out.

The above procedure is particularly advantageous when the crane operator is depositing cargo containers in the hold of a ship where the actual situation of the container cannot be observed by sight. The lamps 86', 88' and 90' on the container head itself will also warn longshoremen, ships crew, etc., of the intended operation of the device. The overall system has been found highly advantageous in the expeditious and safe loading and unloading of container cargoes.

While we have shown and described a preferred embodiment of our invention, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. We therefore intend the appended claims to cover all such changes and modifications as fall within the true spirit and scope of our invention.

We claimi 1. A crane system for moving a cargo container, said system comprising:

a crane having a crane boom and a crane operator's cab,

a container head adapted to be received upon the top of said container, said container head having four remotely operated locking members located substantially at corners of said container head for engaging mating locking devices provided at the top of a container,

cable means for suspending said container head and container locked thereto from said crane boom,

21 first group of four switching devices located on the container head and responsive to the containers presence for preventing unlocking of said locking members when said container head is not resting on said container,

four additional switching devices located on the container head and responsive to operation of said locking members,

and indicating means located in the operators cab and electrically coupled to said container head for indicating to the crane operator the position of said first group of four switching devices and the position of said four additional switching devices,

whereby, when the crane lifts the container, said container head is not resting on said container and upon lowering of the container onto a supporting surface said container head rests on the container and said indicating means thereby provides an indication to an operator in said operators cab that the container is fully down on the said supporting surface.

2. The system according to claim 1 wherein said first group of four switching devices comprise pressuresensitive switching devices located substantially at corners of said container head and operative when the weight of said container head is not resting on said container for inhibiting unlocking operations of said locking members.

3. The system according to claim 2 wherein said first group of switching devices are each provided with an actuator movable upwardly and downwardly according to whether the weight of said container head rests on said container or said container head carries said container as the same is upraised by said cable means.

4. The system according to claim 3 wherein said first 5 group of four switching devices have normally open contacts connected in series in an interlocking circuit for providing power to said locking members, each of said first group of switching devices being operable from a normally open to a closed condition as the actuator therefor indicates said container head is resting on said container.

5. The system according to claim 4 also including indicating means on said container head for indicating the position of said switching devices and the position of said locking members.

6. The system according to claim 1 wherein said cable means comprises a pair of cables extending from a crane boom adapted to be raised and lowered from a pair of drums,

a spreader bar suspended at respective ends thereof by said pair of cables for positioning said cables apart, including means for connecting said spreader bar to said pair of cables,

and further pairs of cables extending from each end of said spreader bar to corners of said container head wherein the last mentioned pairs of cables make an angle of nearly l80 with the first mentioned pair of cables for carrying said container head and container with a minimum of container head weight-carrying structure.

7. The system according to claim 1 further including a plurality of hingeable guides located on said container head and adapted to be rotated into a position extending downwardly from said container head for contacting sides of said container when said container head is moved into place, upon said container,

said guides each comprising a first arm pivotally con nected to said container head and operating means for rotating said arm from an upraised position to a downwardly extending position for juxtaposition with a side of a container,

and hook means on the side of said container head for receiving a portion of each said arm for bracing each said arm in said downwardly extending position relative to thrust of horizontal forces against said arm as said arm encounters the side of a container.

8. The system according to claim 7 including means for remotely operating said guides in groups.

9. A crane system for moving a cargo container, said system comprising:

a crane having a crane boom and a crane operators cab,

four switching devices located on the container head and responsive to the conntainers presence for preventing unlocking of said locking members when said container is present,

indicating means located in the operator's cab and electrically coupled to said container head for indicating to the crane operator the position of said switching devices and the position of said locking members,

a plurality of hingeable guides located on said container head and adapted to be rotated into a position extending downwardly from said container head for contacting sides of said container when said container head is moved into place, upon said container,

said guides each comprising a first arm pivotally con- 1 nected to said container head and operating means for rotating said arm from an upraised position to a downwardly extending position for juxtaposition with a side of said container,

a linkage for rotating said arm, said linkage comprising second and third arms pivotally connected to the first mentioned arm and said container head respectively and pivotally connected to one another, said operating means comprising a hydraulic cylinder for rotating the third arm pivotally connected to said container head,

and means on the side of said container head for bracing each said first mentioned arm in said downwardly extending position relative to thrust of lateral forces against said arm as said arm encounters the side of a container.

10. The system according to claim 9 wherein said means for bracing comprises a hook-shaped member on the side of said container head having an upwardly facing opening for receiving the pivotal connection between tirst and second arms as the first arm rotates downwardly, the side of said hook-shaped member resisting lateral force against said first arm as said first arm encounters the side of said container.

11. A crane system for moving a cargo container,

said system comprising:

a crane having a crane boom and a crane operator's cab,

a container head adapted to be received upon the top of said container, said container head having four remotely operated locking members located substantially at corners of said container head for engaging mating loclting devices provided at the top of a container,

four switching devices located on the container head and responsive to the container's presence for preventing unlocking of said locking members when said container is present,

indicating means located in the operators cab and electrically coupled to said container head for indicating to the crane operator the position of said switching devices and the position of said locking members,

a pair of clutch-operated tag motors mounted on the crane which suspends said cable means,

said tag motors being separately operable and each including a reel and a tag cable drawn around a said reel,

and sheave means mounted on the boom of said crane at an intermediate location along the length thereof,

the cable from the tag motor reels passing over said sheave means to separate locations on the side of said container head.

Claims

1. A crane system for moving a cargo container, said system comprising: a crane having a crane boom and a crane operator''s cab, a container head adapted to be received upon the top of said container, said container head having four remotely operated locking members located substantially at corners of said container head for engaging mating locking devices provided at the top of a container, cable means for suspending said container head and container locked thereto from said crane boom, a first group of four switching devices located on the container head and responsive to the container''s presence for preventing unlocking of said locking members when said container head is not resting on said container, four additional switching devices located on the container head and responsive to operation of said locking members, and indicating means located in the operator''s cab and electrically coupled to said container head for indicating to the crane operator the position of said first group of four switching devices and the position of said four additional switching devices, whereby, when the crane lifts the container, said container head is not resting on said container and upon lowering of the container onto a supporting surface said container head rests on the container and said indicating means thereby provides an indication to an operator in said operator''s cab that the container is fully down on the said supporting surface.

2. The system according to claim 1 wherein said first group of four switching devices comprise pressure-sensitive switching devices located substantially at corners of said container head and operative when the weight of said container head is not resting on said container for inhibiting unlocking operations of said locking members.

4. The system according to claim 3 wherein said first group of four switching devices have normally open contacts connected in series in an interlocking circuit for providing power to said locking members, each of said first group of switching devices being operable from a normally open to a closed condition as the actuator therefor indicates said container head is resting on said container.

6. The system according to claim 1 wherein said cable means comprises a pair of cables extending from a crane boom adapted to be raised and lowered from a pair of drums, a spreader bar suspended at respective ends thereof by said pair of cables for positioning said cables apart, including means for connecting said spreader bar to said pair of cables, and further pairs of cables extending from each end of said spreader bar to corners of said container head wherein the last mentioned pairs of cables make an angle of nearly 180* with the first mentioned pair of cables for carrying said container head and container with a minimum of container head weight-carrying structure.

7. The system according to claim 1 further including a plurality of hingeable guides located on said container head and adapted to be rotated into a position extending downwardly from said container head for contacting sides of said container when said container head is moved into place, upon said container, said guides each comprising a first arm pivotally connected to said container head and operating means for rotating said arm from an upraised position to a downwardly extending position for juxtaposition with a side of a container, and hook means on the side of said container head for receiving a portion of each said arm for bracing each said arm in said downwardly extending position relative to thrust of horizontal forces against said arm as said arm encounters the side of a container.

9. A crane system for moving a cargo container, said system comprising: a crane having a crane boom and a crane operator''s cab, a container head adapted to be received upon the top of said container, said container head having four remotely operated locking members located substantially at corners of said container head for engaging mating locking devices provided at the top of a container, cable means for suspending said container head and container locked thereto from said crane boom, four switching devices located on the container head and responsive to the conntainer''s presence for preventing unlocking of said locking members when said container is present, indicating means located in the operator''s cab and electrically coupled to said container head for indicating to the crane operator the position of said switching devices and the position of said locking members, a plurality of hingeable guides located on said container head and adapted to be rotated into a posiTion extending downwardly from said container head for contacting sides of said container when said container head is moved into place, upon said container, said guides each comprising a first arm pivotally connected to said container head and operating means for rotating said arm from an upraised position to a downwardly extending position for juxtaposition with a side of said container, a linkage for rotating said arm, said linkage comprising second and third arms pivotally connected to the first mentioned arm and said container head respectively and pivotally connected to one another, said operating means comprising a hydraulic cylinder for rotating the third arm pivotally connected to said container head, and means on the side of said container head for bracing each said first mentioned arm in said downwardly extending position relative to thrust of lateral forces against said arm as said arm encounters the side of a container.

10. The system according to claim 9 wherein said means for bracing comprises a hook-shaped member on the side of said container head having an upwardly facing opening for receiving the pivotal connection between first and second arms as the first arm rotates downwardly, the side of said hook-shaped member resisting lateral force against said first arm as said first arm encounters the side of said container.

11. A crane system for moving a cargo container, said system comprising: a crane having a crane boom and a crane operator''s cab, a container head adapted to be received upon the top of said container, said container head having four remotely operated locking members located substantially at corners of said container head for engaging mating locking devices provided at the top of a container, cable means for suspending said container head and container locked thereto from said crane boom, four switching devices located on the container head and responsive to the container''s presence for preventing unlocking of said locking members when said container is present, indicating means located in the operator''s cab and electrically coupled to said container head for indicating to the crane operator the position of said switching devices and the position of said locking members, a pair of clutch-operated tag motors mounted on the crane which suspends said cable means, said tag motors being separately operable and each including a reel and a tag cable drawn around a said reel, and sheave means mounted on the boom of said crane at an intermediate location along the length thereof, the cable from the tag motor reels passing over said sheave means to separate locations on the side of said container head.