US3734324A - Container handling frame - Google Patents

Abstract

A frame for handling cargo containers is disclosed. A vertical member of the frame is mounted on the carriage of an industrial lift truck having an extensible mast. The housing at the upper end of the vertical member contains a pair of transversely extensible arms. Powered by a pair of hydraulic motors, these arms may be moved inwardly or outwardly along their longitudinal axis by the truck operator so as to position each arm to engage the upper corner fittings of a cargo container from one side. When thus positioned and engaged, the frame and truck may lift and move the cargo container.

Description

United States Patent [191 Lynch et al.

[ 1 May 22, 1973 [54] CONTAINER HANDLING FRAME [75] Inventors: Peter D. Lynch, Portland, Oreg.; Dempsey R. Oldfield, Half Moon Bay, Calif.; Donald K. Zifka, Mill [21] Appl. No.: 61,284

3,166,207 1/1965 Quayle ..294/67 BB X 3,387,730 6/1968 Levitt ..214/621 3,558,176 1/1971 Fathauer 294/81 SF X 3,182,837 5/1965 Farmer.... 294/67 BB X 3,552,557 1/1971 Green ..214/620 3,514,146 5/1970 Zweifel et al.... ...294/81 SF X 3,387,729 6/1968 Hinden et a] ..214/621 Primary Examiner--Robert J. Spar Attorney-Francis Swanson [57] ABSTRACT A frame for handling cargo containers is disclosed. A vertical member of the frame is mounted on the carriage of an industrial lift truck having an extensible mast. The housing at the upper end of the vertical member contains a pair of transversely extensible arms. Powered by a pair of hydraulic motors, these arms may be moved inwardly or outwardly along their longitudinal axis by the truck operator so as to position each arm to engage the upper corner fittings of a cargo container from one side. When thus positioned and engaged, the frame and truck may lift and move the cargo container.

1 Claim, 11 Drawing Figures Patented May 22, 1973 3 734 324 3 Sheets-Sheet l :I fl ll INVENTORS PETER D. LYNCH DEMPSEY R. OLDFIELD og w K. ZI FKA llfiome 7 Patented May 22, 1973 3,734,324

5 Sheets-Sheet 2 INVENTORS PETER D. LYNCH DEMPSEY R. OLDFIELD DONALD K. ZIFKA flfforney Patented May 22, 1973 3,734,324

5 Sheets-Sheet 3 PETER 0. LYNCH DEMPSEY R. OLDFIELD DONALD K. ZIFKA Rm Ru W l 8' INVENTORS CONTAINER HANDLING FRAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to frames for lifting and moving cargo containers and particularly to extensible container handling frames for use with an industrial truck having an upright and carriage.

2. Description of the Prior Art In recent years freight cargo containers have begun to play a significant role in the transportation industry. Such containers are uniform in size and shape and have a large capacity. They are constructed of a wide variety of materials and range in weight, when fully loaded, up to 75,000 lbs. I

These containers are usually 8 feet high, 8 feet wide, and commonly 20 to 40 feet in length. The containers have standardized corner fittings which enable them to be moved by equipment commonly found at larger ports, truck docks and rail terminals. These prior art devices include straddle carriers, crane type machines, and industrial lift trucks with special front end attachments. The latter type of equipment is most similar to the present invention. Such attachments usually consist of a rigid horizontal rectangular frame attached to the forks of the industrial truck. This rigid frame usually has a set of downwardly depending latch mechanisms which engage the cargo container at the top of its four upper corner fittings. The container can then be picked up and moved. A limitation of such systems has been their inability to handle more than one size container. A 20 foot container requires a 20 foot handling frame; a 40 foot container, a 40 foot frame and so on.

A further limitation of such systems lies in their heavy weight which requires a larger capacity truck. Virtually all such systems have in the past been top attaching.

SUMMARY OF THE INVENTION One requirement of all such industrial truckcontainer handling attachment combinations is that they must operate from one side of the container. In accordance with the present invention an upright container frame handling attachment for use with an industrial truck is provided. One object of the invention is to provide a container handling frame that is adjustable to fit a wide range of container sizes.

A further object of the invention is to provide a container handling frame that may satisfactorally pick up containers by attaching the fittings of one side only. A still further object of the invention is to provide a container handling frame design wherein torque forces induced in the extensible arms of the frame tend to cancel one another.

DESCRIPTION OF THE DRAWINGS The foregoing and other features, objects and advantages of the present invention will be more apparent from the following detailed description which proceeds with reference to the accompanying drawings wherein:

FIG. 1 is a side view of an industrial truck showing the container frame mounted on the carriage. A cargo container is shown in phantom.

FIG. 2 is an end view of the container handling frames housing, drive mechanism, and extensible arms, partially broken away to show interior details. The drawing also shows a break-away view of one container corner fitting with a lifting hook from said extensible arm inserted within it.

FIG. 3 is a sectional view of the lifting hook taken along line 3-3 of FIG. 2.

FIG. 4 is a sectional view of the drive mechanism taken along line 4-4 of FIG. 2.

FIG. 5 is a perspective view of the container handling frame.

FIG. 6 is a perspective view of the bottom bumper.

FIG. 7 is a sectional view taken along line 7-7 in FIG. 5.

FIG. 8 is a perspective view of the lifting arm construction.

FIG. 9 is a diagram of forces at a lifting point on a container.

FIG. 10 is a diagram of hook forces in the general case.

FIG. 11 is a diagram of hook location for torque cancelling.

DETAILED DESCRIPTION Referring now to the drawings, the container handling frame has an upright member 10 mounted on the carriage 12 of an industrial lift truck 14. The unit is shown engaging a cargo container 16 in fittings 17. Member 10 has a housing 18 mounted at its upper end. The frame 10 also has a pair of diagonal bracing members ll connecting it to housing 18. The upright member 10 is also braced with a cross member 13 and has a bumper plate 15 mounted at its lower end. The housing 18 contains a pair of extensible arms 20 and 22. Each extensible arm has a rigid rectangular tube 24 mounted upon it. As viewed in FIG. 5 the leftward extending arm 22 mounts a load lifting hook 26 at its outermost end. As viewed in FIG. 5 the rightward extending arm 20 mounts a loading hook 28 at its outermost end. The housing 18 has mounted on its upper side along its longitudinal axis, a pair of guide channels 30 and brackets 31 which receive rigid rectangular tubes 24 from arms 20 and 22. At the ends of each tube 24 is mounted a chain 32. Each chain 32 is reeved under idler sprockets 34 mounted on housing 18. Each chain is further reeved over sprocket 36 which is mated to shaft 38 of hydraulic motor 40 which is mounted on the housing 18 by means of brackets 42 which also mount idlers 34.

From the hydraulic motors 40 supply lines 44 run to control valves 19. Oil from the conventional lift truck supply system is used to power motors 40.

Thus far, this disclosure has been directed to the objects, advantages, and general characteristics of the invention. To completely understand the nature of the invention it is necessary to turn to certain elementary theoretical considerations. The discussion following is offered only in the qualitative sense and only for the purpose of more clearly illustrating the invention. FIG. 9 shows an analysis of the horizontal and vertical forces acting on a standard 8 by 8 container when picked up from one side by that sides top fittings. The analysis assumes that load W of the container is horizontally centered. Thus the position of the horizontal center of gravity (C6,) is four feet from one edge of the container. Thus in an equilibrium condition the resultant force in a vertical direction (R,,) will equal the weight of the container load (W). Further, in an equilibrium condition the force acting in a horizontal direction must equal zero. Thus from FIG. 9 resultant forces at the upper edge (R,,) must equal the resultant forces at the lower edge (R and R R Also, assuming equilibrium and picking the container up at the corner pocket point P we have the sum of the moments about P EM, R (8 feet) W(4 feet) or R 12W. Substituting R for R and R,, for W, the expression reads R,, %R,, or R, 2R,,. From this it can be seen that the angle 0 of the resultant line of force acting through point P is Tan 6 R /R 2. This is approximately equal to 6326 from the horizontal, the tangent of this angle being 1.9998.

This relation holds true for any length container and for any vertical center of gravity as long as its cross section is square and it is horizontally supported at its bottom edge by a bumper.

Now, if the container is to be picked up from one side, this relation assumes considerable importance in the placement of the loadlifting hooks on the transverse arms 20 and 22. Ideally the torque forces induced in beam 20 should be used to oppose and cancel the torque forces induced in beam 22. Using the relation previously derived from the resultant force in the container, it is now possible to determine precisely where to place the load engaging hooks.

Refer now to FIG. 10. This shows the analysis of the general case for placing the hooks. B is a cross-section of a beam B with a hook H on it. S is the shear center of the beam B. The shear center of a beam. is defined and described in detail at pages 97 to l 1 1 of the book Advanced Mechanics of Materials, second edition 1952, written by Fred B. Seely and James O. Smith, and published by John Wiley & Sons, New York.

Consider now a force directed along the line of action R at the point P on the hook H. This force can be resolved into its horizontal component R and its vertical component R,,. The value of R, is R cos 0 and the value of R, is R sin 0. D is the perpendicular distance from shear center S to P in the horizontal plane. D is the perpendicular distance from S to P in the vertical plane. Thus the product of R, and D will produce a clockwise torque of T about shear center S Likewise the product of R and D will produce a counterclockwise torque T about shear center S The hook can be placed so that the line of action passing through P will satisfy the following relation: R, X D R,, X 0,. Under this condition the sum of the torque forces induced in the beam is zero. This means that the line, of action R also passes through the shear center S, as well as P.

It is easily seen that where point P is placed so that the line of action R, when directed downward and to the right as in FIG. 10, lies at the left of the shear center 8,, a counterclockwise torque will result. Likewise, placement of the point P so that the line of action R, when directed downward and to the right as in FIG. 10, lies to the right of the shear center 8,, a clockwise torque will result. This relationship is true for any shape of beam and downward orientation of the line of action relative to the shear center and may be used to determine the placement of hooks in all cases. From this analysis it is seen that by adjusting either D or D, or both in combination it is possible to apply a clockwise or counterclockwise torque of known value to the beam B.

FIG. 1B represents the analysis of hook 26 and hook 6 28 of the invention and is a specific case covered by the general case shown in FIG. 10. From the analysis of FIG. 9 the line of action on a container being picked up is approximately 6326 to the horizontal and force component R, 2R,,. When hooks as in FIG. 11 pick up the container, the line of action R is the same as R in FIG. 9 and R, and R, in FIGS. 9 and II have the same values. In a design employing side-by-side arms as in this invention, the shear centers of the respective beams are placed so that the dimension D of FIG. 11 is constant for both hooks. This is readily seen from FIG. 2. Therefore the balancing of torque forces is dependent on the relation between the constant D and the dimensions D, and L, which must necessarily be different in each arm and hook as in FIG. 2.

In FIG. 1 1 it is seen that for the torque forces to cancel the following relation must be satisfied:

Substituting 2R for R, in the above and solving, we have:

This relationship defines the placement of the hooks to achieve torque cancelling.

OPERATION To illustrate the operation of the container handling frame assume that the operator of truck 14 wishes to pick up a 40 foot container and the extensible arms 20 and 22 of the container handling frame are positioned to pick up only a 20 foot container. As in FIG. 1, the operator approaches container 16 from one side. He elevates carriage 12 until it is approximately level with the top container 16. Using the controls 19 on the truck 14 the operator extends arms 20 and 22 independently until each is properly aligned with its respective top fitting 17. When the controls 19 are actuated to move either one of the extensible arms, the hydraulic motor 40 for the appropriate arm, which is mounted on housing 18, begins. to turn. Sprocket 36 of motor 40 is engaged with chain 32 which is fastened at both ends to tube 24 as previously stated. The turning of sprocket 36 causes movement of chain 32 which in turn moves the arm in the direction desired. After moving load hooks 26 and 28 into positions opposite fitting 17, the operator tilts the carriage l2 forward slightly and drives the truck slowly forward until said hooks are inserted into said pockets. The operator then raises the carriage l2 and brings the container 16 to bear against bumper 15. The container may now be elevated and moved by the truck to any desired location. To deposit the container 16 and disengage the container handling frame, the above sequence of steps is merely reversed.

Having illustrated and described the preferred embodiment of our invention, other modifications in arrangement and detail will occur to those skilled in the art. We claim as our invention all such inventions as come within the true spirit and scope of the following claims:

We claim:

1. A cargo container handling frame including an upright member;

means for mounting said frame on a lift truck carriage;

unitary housing means mounted horizontally on said upright member;

bumper means mounted at the lower end of said upright member;

front and rear load lifting arms reciprocally mounted in a horizontal plane in side by side relation at least partially within said housing;

a first hook mounted on said rear arm, the load engaging portion of said hook positioned below and 5 protruding substantially outward from the front side of said arm so as to apply torque about the longitudinal axis of said arm when lifting a load;

a second hook mounted on said front arm, the load engaging portion of said hook positioned below within said housing when said arms lift a load.

Claims (1)

1. A cargo container handling frame including an upright member; means for mounting said frame on a lift truck carriage; unitary housing means mounted horizontally on said upright member; bumper means mounted at the lower end of said upright member; front and rear load lifting arms reciprocally mounted in a horizontal plane in side by side relation at least partially within said housing; a first hook mounted on said rear arm, the load engaging portion of said hook positioned below and protruding substantially outward from the front side of said arm so as to apply torque about the longitudinal axis of said arm when lifting a load; a second hook mounted on said front arm, the load engaging portion of Said hook positioned below and to the forward side of the longitudinal axis of said arm so as to apply a torque about said longitudinal axis substantially equal to and opposite that applied to said rear arm when lifting a load; whereby torque forces applied to said rear arm acting within said housing oppose and substantially cancel torque forces applied to said front arm acting within said housing when said arms lift a load.

Images