US 3888536 A
A container handling system which includes a generally rectangular spreader bar having hydraulic control means for the purpose of locking and unlocking corner attachments to the spreader frame.
Description (OCR text may contain errors)
I June 10, 1975 United States Patent IWI Durenec 294/67 R 4. 294/67 DA 294/81 SF 3.428.354 2/1969 Grif'fith 3.501.193 3/1970 Gruy 3.712661 [/1973 Strandm.v
3.767.250 10/1973 Ward l73| Assignec: The United States of America as Primary Examiner-Even C. Blunk Assislunl Examiner-Johnny D. Cherry a ti.
an S en m HM Mm U nW Attorney. Agent. or Firm-Robert P. Gibson; Nathan Edelberg Filed: Jan. 29, 1974 121 App]. No.: 437.566
ABSTRACT 294/82 SF: 294/67 DA Int. 1366c 1/66 n w f searchmmm 294 67 DA, A container handling system which includes a gener- 294/67 DB g[ 1 5 0 R 7 ally rectangular spreader bar having hydraulic control means for the purpose of locking and unlocking corner attachments to the spreader frame [56l References Cited UNITED STATES PATENTS 4 Claims, 2 Drawlng Figures 2.847245 8/1958 294/110 R PATENTED H 0 I975 3.888.536
SE'IEEI 2 POWER SOURCE ACTUATOR AcTuAToR CLOSED OPEN 28 DELAY AND 24 24 FLIP-FLOP A MATED 23 AND 25 AND 25 CLOSE OPEN AI TOMATK' SELF ('UNTAINIQI) LIGHT WEIGHT SPREADER [HR The invention described llcl'clll may he manufactured. used. and licensed by or for the government for governmental purposes without the payment to me of any royalties thereon BACKURUIND ()I 'I'Hl: INVENTION The present invention relates to equipment for lifting cargo containers by means of helicopters or various types of cranes such as a gantry crane. boom crane. straddle crane or the likev In the past the cargo industry has employed \tll'ititts equipment often referred to as spreader frames or spreader bars to transfer cargo from ship to shore or between ground locations. This equipment used with gantry cranes and boom cranes is constructed of struc tural steel which weighs from 1.5 tons for a manual fixed length unit to 7 tons for an adjustable length unit with retractable corner guides and self-leveling systems. This high weight has made such spreader bars incompatible with helicopter use. In addition. spreader frames of the past have not had the rapid pickup and release necessary to take full advantage of helicopter lift capability.
While some existing devices do connect cargo envelopes to a helicopter. they are designed and built to meet only a specific parameter.
SUMMARY OF THE INVENTION The primary object of the invention is to provide a spreader bar assembly which is compatible with helicopter lift characteristics in general.
Another object of the invention is to provide a spreader bar assembly that can be used with any crane. any aircraft, or even with a forklift equipped with a hooking device having the required lifting capability.
Still another object of the invention is to provide an assembly which is comparatively lightweight /2 ton). entirely self-contained and generates its own energy source for operation A further object of the invention is to provide a spreader bar assembly which is fully automatic in its locking and unlocking to the cargo container and which additionally provides a visual indication of whether the container is in a locked or unlocked condi tion.
BRIEF DESCRIPTION OF THE DRAWING The exact nature of the invention will be readily apparent from a consideration of the following specification relating to the annexed drawings in which:
FIG. I is a perspective view of u spreader frame of the preferred embodiment of the in\cntion using single point suspension; and
FIG. 2 is a schematic diagram of the logic used in the automatic hydraulic control system of the present invention.
DETAILED DESCRIPTION OF THI INVENTION Referring to Fl(i. I of the drawing. there is shown spreader frame II which is suspended from a single point by four carrying cables I2 which attach to the corners of frame II. l-ach of the carrying cables I2 is of s inch diameter teel. At each corner of spreader frame I I there is a t\\ ist lock I3 suitable to accommodate the dimensional requirements of an 8 X 8 X It) (ill foot container. From the single point suspension. at fifth line e\tends downward. This line 14 is not a carrying line. but serves to activate an automatic piston pump 15 which reacts to every slack of the activator line. Any vertical movement of the line 14 generates energy and transfers it to an accumulator 16. Any lifting movement reaching two feet of stroke develops enough energy to operate all four twist locks I3 thirty times full cycle. In addition. two of the four corners in diagonal location have a touch-down sensor I7. When both ofthe sensors are in complete contact with the corner fittings of the container. a signal will be dispatched through the hydraulic system to logic 16 where a flip-flop valve autt matically activates the hydraulic cylinder I8 and passes the force through shaft I9 and push rod 20 to the twist locks 13 with the assistance of the control valve 21 and reservoir 22. The hydraulic system begins charging the instant the spreader bar assembly is lifted because of the movement and its own weight by vertical motion.
The twist locks 13 have indicators painted green for open position and red for closed position, and are located in such a way that they are visible to an aircraft operator. Two additional visual indicators are located on the long sides of the frame and have the same color coding. The indicators serve a dual purpose. They are employed as leverage controls for the manual override. and they also show the ground operator the actual position of the locks l3. Therefore. the safety and security of the spreader assembly is protected by three controls: automatic, manual and manual/hydraulic.
In operation. the operator aligns the spreader assembly above the container top and starts to lower the assembly. The twist locks I3 are in the open position and all indicators show green. Upon contact of the spreader assembly with the four corner fittings of the container. the two sensors 17 are compressed and send a signal to the logic 16 which causes the twist locks 13 to simultaneously close and the visual indicators to change to red.
During transport, the sensors I7 are not in contact with the corner fittings. To prevent accidental sensor signals to the logic 16 which could be caused by vertical motion such as an air pocket or zero load. an adjustable built-in delay can be set from zero to five seconds. Upon arrival at destination and lowering. the spreader assembly must rest until the delay time is reached. Only when the slings 12 have the required slack will the twist locks 13 automatically open and the indicators turn green. Any vertical motion of the assembly charges the hydraulic system; therefore, energy not consumed is stored in the logic assembly 16 and the spreader is always ready for operation.
Referring now to FIG. 2, there is shown a logic diagram of the automatiic control system. The realization of the diagram as actual hardware can be accomplished by electrical. pneumatic. or hydraulic means. In the preferred embodiment. hydraulic means was chosen because of simplicity. reliability and ruggedness. In such a system the elements of the logic diagram take the form of hydraulic valves. The actuator I8 is controlled by a three-way center-off valve with spring return to the center position. whose spool is actuated by a pilot cylinder in each direction. The OR gate 23 is a two-input shuttle valve permitting flow from either input to the output line. but preventing feedback from one to the other. The two-input AND gates 24 are pilot actuated spring return normally off valves. which supply no output pressure unless they receive input pressure at both the normal inlet part and the pilot cylinder. The multiple input AND gates 25 can be built up as assemblies of two or more such valves The sensors are mechanically actuated directional control valves with a spring return and toggle positioning mechanism. fitted for actuation by push rod. lever or cam follower roller as the mechanical design may dictate. The flip-flop element 26 of the logic design is a double pilot two position directional control valve with a toggle positioning mechanism that holds the control spool in one open po sition until pressure is applied to the pilot cylinder on that side and then snaps the spool over into the oppo site open position. The inverting element 27 may be a two position pilot actuated directional control valve. The delay 28 is a small accumulator with one or more flow restriction valves to control its rate of pressure build-up and drainv An additional pilot actuated control valve can be included as a comparator to insure that the delayed signal is generated when the pressure in the accumulator reaches a definite fraction of a reference pressure existing elsewhere in the system.
Although one embodiment of the invention has been shown and described. it will be understood that various modifications may be made without departing from the spirit and scope of the invention.
What is claimed is:
l. in a cargo container handling system. a spreader bar assembly including:
a moveable support;
a rectangular frame with corner attachments connected to said support;
a hydraulic power source assembly embodying a hy draulic piston means adapted such that selected movement of said piston means readies said hydraulic power source assembly for operation;
hydraulic control means for locking and unlocking the corner attachments of the spreader frame. said hydraulic control means including safety interlock means disposed at each point of attachment and responsive to the relative position of said spreader frame with respect to a cargo container. said control means adapted to lock and unlock corner at tachments substantially simultaneously when a selected relative positioning of said spreader frame with respect to a cargo container occurs and the spreader frame concurrently fully rests on the cargo container; and
means connecting said hydraulic piston means of said hydraulic power source assembly to said move-able support such that a lift motion of said move-able support, with said spreader frame resting on the cargo container and undisturbed by said lift motion. pressurizes said hydraulic power source assembly.
2. The assembly of claim 1 wherein the moveable support includes a single hook by which the spreader frame is supported and said means connecting said hydraulic piston means of said hydraulic power source to said moveable support is a relatively short cable means which is attached to said single book on said moveable support.
3. The assembly of claim 2 wherein said safety interlock means are load responsive means and include time delay means such that said safety interlock means react to a selected load less than the full weight of said spreader frame when said safety interlock means is subjected to said selected load over a selected period of time.
4. The apparatus of cliam 3 further including means for visually determining when said interlock means are secure.
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