US2637453A

US2637453A - Apparatus for loading truck trailers on ships

Info

Publication number: US2637453A
Application number: US135232A
Authority: US
Inventors: Henry D Cleveland
Original assignee: Individual
Current assignee: Individual
Priority date: 1949-12-27
Filing date: 1949-12-27
Publication date: 1953-05-05
Anticipated expiration: 1970-05-05

Description

May 5, 1953 H. D. CLEVELAND APPARATUS FOR LOADING TRUCK TRAILERS on SHIPS 8 Sheets-Sheet 1 Filed Dec. 27, 1949 IVE TR. Q HENEY D. filEVEL AND. BY 0% A TwKA/EK y 1953 H. D. CLEVELAND 2,637,453

APPARATUS FOR LOADING TRUCK TRAILERS OR SHIPS Filed Dec. 27, 1949 8 Sheets-Sheet 5 FIG.4.

54 llll u k v FIG.6.

y 1953 H. D. CLEVELAND 2,637,453

\ APPARATUS FOR LOADING TRUCK TRAILERS 0N saws Filed Dec. 27, 1949 8 Sheets-Sheet 4 FIG 9 INVENTOR.

HENRV D. CLEVELAND.

A T' ORNEY,

5, 1953 H. D. CLEVELAND 2,637,453

APPARATUS FOR LOADING TRUCK TRAILERS ou SHIPS Filed Dec. 27, 1949 8 Sheets-Sheet 5 L l W I J HWIHL 4M Wm" hm nn HW- W II'H' IN V EN TOR. HEM? y 12 a EVEL/WD.

ATTORNEK May 5, 1953 H. DACLEVELAND 2,637,453

APPARATUS FOR LOADING TRUCK TRAILERS ON SHIPS Filed Dec. 2'7, '1949 8 Sheefcs-Sheet 6 FIG. I2.

H6 '3 HE /W2. CLEVEMND.

BYVW

A TTO/ZNE Y.

y 5, 1953 H. D. CLEVELAND 2,637,453

APPARATUS FOR LOADING TRUCK TRAILERS 0N SHIPS I Filed Dec. 27, 1949 8 Sheets-Sheet 7 FIG. :5. 68 27 IN V EN TOR. HEN/P Y a CLEVEMND.

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W WWW May 5, 1953 H. 0. CLEVELAND 2,637,453

APPARATUS FOR LOADING TRUCK TRAILERS on SHIPS Filed Dec. 27, 1949 a Sheets-Sheet 8 IX j g j I 5 1 g IN TOR.

HEN/Q Y D. C VELA/VD.

Patented May 5 1953 UNITED STATES PATENT OFFICE APPARATUS FOR LOADING TRUCK TRAILERS ON SHIPS Henry D. Cleveland, New York, N. Y.

Application December 27, 1949, Serial No. 135,232

2 Claims. 1

This invention relates to ship construction and method and apparatus for loading and supporting truck trailers on ships, for storing them thereon and for thereafter unloading them therefrom, thereby linking the highway and the waterway.

The present invention constitutes an improvement over the invention shown and described in applicant's co-pending application, Serial No. 19,215, filed April 6, 1948, now abandoned. The co-pending application describes a method of loading and unloading trailers across the sides of the ship. Movable gangways are therein provided for this purpose, and the trailers are stored on the ships decks, athwartship, and rest upon their own wheels. It has been found that movable gangways, while practicable and practical, do possess certain disadvantages which are not inherent in conventional gangways, and it is accordingly a principal object of this invention to provide loading and unloading apparatus of the character described wherein conventional gangways are utilized for loading and unloading the truck trailers. These conventional gangways are permanent features of the wharves or piers where they may be used to load and unload both sides of the ship simultaneously as well as two or more decks simultaneously.

Another disadvantage of the apparatus disclosed in said co-pending application resides in the fact that it relates solely to leading and unloading the ship but it does not provide facilities for properly storing the truck trailers on board ship and securing them against the pitch and roll at sea. It is, therefore, another principal object of this invention to provide apparatus for properly storing the truck trailers on board ship, said apparatus including means for elevating the truck trailers so that the load is removed from their wheels and for supporting the trailer chassis directly by supporting means carried by the ship.

In the form of the invention shown in the copending application, movable gangways are provided so that the truck trailers may be loaded on board ship at selected locations. In the present form of invention, one or more conveyor systems are provided on each deck of the ship, and these conveyor systems perform the function of properly stowing the truck trailers on board ship. It is, therefore, still another important object of the invention to provide apparatus on board ship for handling the truck trailers thereon, and moving them from one location to another.

The advantages of the present invention are manifold. In the first place, the apparatus herein described and claimed renders it possible to load and unload trailers at a faster rate of speed than is possible with any other kind of apparatus. In the second place, the cost of constructing and maintaining conventional gangways as distinguished from travelling gangways, is exceedingly low. In the third place, a constant draft is maintained both at sea and in port, except when the ship is out of service and this, of course, simplifies and facilitates the operation. In the fourth place, the present apparatus requires that one truck trailer be unloaded before another can be loaded to take its place and hence, the ship will always be maintained at an even keel. A fifth advantage is inherent in the fact that the truck trailers are anchored quickly and firmly to the ship as soon as they are loaded thereon, and placed in their proper locations, without the use of lift jacks or other similar apparatus and also without the use of turnbuckles or the like for fastening them to the ships decks. They rest of their own weight on supports which engage their chassis and there is no need for further anchoring them to the ship. A sixth advantage resides in the fact that the truck trailers cannot rock relative to the deck of the ship as would normally be thecase when they rest upon their own wheels and springs. This prevents damage both to the ship and to the trailers, and it also avoids the dangers of a shiftable or otherwise movable cargo. It i also advantageous to the tires and springs of the truck trailers themselves, to remove all concentrated loads therefrom for the period of time it would take the ship to sail from one port to another. A seventh advantage resides in the fact that the truck-supporting apparatus of the present invention avoids the concentrated loads which the decks would otherwise be required to bear, thereby making for a reduction in the weight of the deck plating and of the structural supports on which the deck plating rests. The trailer-truck supporting members may be so designed as to serve as reinforcing members in the ship construction. There are other advantages which are inherent in the present invention.

A principal object of the present invention is the provision of improved and unique trailer supporting means and apparatus for supporting the trailers on the decks of the ship. Specifically, this includes an elevated conveyor belt which supports the back end of the trailers, a second conveyor belt which is disposed at a relatively low level for supporting the front end of the trailers, and a temporary, portable fifth wheel assembly which-is interposed between the front end of each trailer and the second mentioned conveyor belt so that actually the front end of the trailer rests upon the fifth wheel assembly and said assembly rests upon the second mentioned conveyor belt. A ramp is provided for the rear wheels of the trailer so that the back end of the trailer may be raised to the level of the first mentioned conveyor belt. The ramp may be raised or lowered as and when desired. A tractor with a hydraulic lift adapted to engage the fifth wheel assembly is provided to support the fifth wheel assembly during the loading and unloading operations and it is by this means that said fifth wheel assembly may be raised or lowered as and when desired. In other words, the. fifth wheel assembly performs two functions: it is the means whereby the tractor may be coupled to the trailer for loading and unloading purposes, and it is also the means which supports the front end of the trailer on the second mentioned conveyor belt during the course of the ships voyagefrom the port of loading to the port of unloading.

A preferred form of the present invention is shown by way of illustration in the accompanymg drawing, in which:

1 is a side view of a trailer carrying ship made in accordance with the present invention.

Fig. 2 is a cross-sectional view through said ship and it is also a View of some of the shore facilities for loading and unloading the ship.

Fig. 3 is a top view of three such ships, showing. one of them in a slip, the shore facilities for loading and unloading the trailersbeing shown on both sides of the slip.

Fig. is an exploded view .ofthe three elements, in addition to the ship itself, which the present invention involves: the trailer, a portable fifth wheel assembly for said trailer, and a tractor which utilizes said portable fifth wheel assembly in moving the trailer from ship to shore and from shore to ship.

Fig. 5 is an exploded top view of said tractor and said fifth wheel assembly.

Fig. 6 is a side view thereof.

Fig, 7 is a fragmentary side view showing the fifth wheel assembly supported by the tractor and the trailer supported by the fifth wheel assembly.

Fig. 8 is a fragmentary. transverse section through one of the ships showing how the trailers are loaded thereon and unloaded therefrom.

Fig. 9 is a fragmentary. top view of one of the decks of the ship showing two of the conveyor belts which are used to support the trailers and to move them from one position to another on the ship.

Fig. 10 is an enlarged cross-sectional view showing the details of one of the conveyor systems, that is the conveyor system which supports the front end of the trailers.

Fig. 11 is a view looking in the direction of arrows II, II of Fig. 10.

Fig. 12 is a view similar to that of Fig. 10, showingthe conveyor systern which supports the back end of the trailers.

Fig. 13 is a view looking in the direction of arrows l3, [3 of Fig. 12.

Fig. 14 is a fragmentary top view of one of the ramps on which the rear wheels of'the trailer rides up upon and down from the rear conveyor belt.

Fig. 15 is a side view thereof.

Fig. 16 is a diagrammaticview showing the drive, mechanisms for thetwo conveyor belt sys tems.

Fig. 17 is a view similar to that of Fig. 3, but

4 showing different shore facilities for loading and unloading the ship.

The principle of operation of the present invention is as follows: Truck trailers are loaded upon the ship at a given port, they are carried by the ship to a second port, and they are unloaded. Conventional tractors are employed to deliver the trailers to the wharves at the first port and conventional tractors are also utilized to remove the trailers from the wharves at the second part. Special tractors, herein described, and special apparatus, also herein described, are utilized for the purpose of loading the trailers upon the ship and unloading them from the ship. Apparatus is provided on board ship for supporting the trailers, not on their wheels or springs, but rather on their chassis during the course of the voyage between the two ports and the same apparatus, also is employed to move the trailers from place to place on board ship. Said pparatus is also described herein. The facil for loading and unloading the ship are independent of each other the sense that the sl p may be loaded and unloaded at the same time. More specifically, while one trailer is taken oi? the ship, another trailer may be brought aboard ship. An important feature of the pre ent invention, as will more fully hereafter appe is the supporting member which supports the ire-ht end of the trailer both on board ship and while it is being moved either onto or off the ship by means of the tractor.

It. will be seen Figs. 1, 2, and 3, that a ship 20, designed in accordance with the present in vention, is with two decks 2i and 22', respectively, on which trailers 23 may be loaded. Each deck may he considered as being divided into two lon itudinal sections, one on the port side of the ship and the other on its starboard side. Doors 25 are provide-cl on both ides of the ship so that both longitudinal sections may be rendered accessible simultaneously both for loading and unloading purposes. Each longitudinal section is furtherdivided or partitioned by means of transverse bulkheads ii into relativeiy small sections or compartments, each of which is adapted to accommodate a given number of trailers, say eight. (See Figs. 3 and 9.)

Since the ship is divided into port side compartrnents and into starboard side compartments, and since it is provided with doors to said compartments on both sides thereof, it may be loaded and unloaded simultaneously across both sides as Fig. 2 clearly shows.

It will be seen that ship 2% may be broug t into a slip 21' with banks or

wharves

28 and 29 on both sides thereof. some of the trailers may be brought onto the lower deck '22 directly from the wharves and across gangplanlas 3G. Ramps 3i and 32 are needed, however, in order to load trailers upon the upper deck 25. G-angplanks may be employed to bridge the gaps betweenupper deck 2! and ramps 3i and respectively. It will be noted that ramps 3i and 32 parallel the surface of the wharves for a considerable distance on both sides of the ship and they descend to the wharves well beyond the sides of the ship. The parallel sections of ramps 3i and 32 are raised well above the level of wharves 28 and 25 so that trailer trucks may be moved freely beneath said parallel sections of the ramps,

Reference to Fig. 3 will disclose the fact that since the ship under discussion is provided with ten trailer compartments on each deck, that is five on ea"h side thereof, it may be found. clesirable to provide six ramps on each side of the boat, to wit, ramps Ella, all), 3lc, am, 316, and ill), on one side, and ramps 32a, 32b, 32c, 32d, 32c, and 32 on the other side. It will be noted that ramps ilib, 32c, 31d, die, 32b, 32c, 33d, and Site are double lane ramps, that is they are each sufficiently wide to accommodate two trailers side by side. These double ramps are used simultaneously both for loading and unloading the ship as ramps sic, and 32d clearly show. Ramps 3m are ramps of single width and they are used solely for ship-loading purposes. trailers which are loaded upon the ship across ramps ilia and 32a are unloaded from the ship across ramps Eli) and 3%, that is, to be more exact, across ramps corresponding to ramps ill?) 32b at the port of consignment of the ships cargo. By the same token, trailers loaded upon the ship across ramps tie and 32c are unloaded therefrom across ramps 3H and 32 or ramps corresponding thereto at the second mentioned port. It will, of course, be noted that ramps Bi) and 32! are of single width only. This arrangement is shown somewhat more graphically in Fig. 1 since the doors at the ends of the ship are but single doors and the intermediate doors are double doors. Each single door provides either ingress or egress for a single trailer, whereas each double ooor provides gress for one trailer and egress for a second trailer simultaneously.

Fig. 3 also shows how the trailers are on the wharves to facilitate loadi and unlo dthe ship. They are arran ed spaced groups, each group correspon to a given trailer compartment on board s As one trailer from any one compartment on board ship is removed, another trailer from a on group of trailers is brought onto the ship and placed in the same compartment. The vacated place on the wharf is now filled by the trailer which was thus removed from the ship and its plac on board ship is filled by shifting the remain trailers in that particular compartment a Mrstance equal to the width of one trailer in the direction of the vacated place in said coinpartment. Hence, the adjacent trailer takes the place of the removed trailer and by the same token a space is rendered vacant at the opposite end of the compartment for the newly loaded trailer. This process continues until all of the trailers of a given compartment are removed from the ship and all of the trailers of a given group of trailers on the wharf are loaded on board ship to take the places of the removed trailers. The same process causes the removed trailers to sume the locations on the wharf vacated by the newly loaded trailers. Since loading unloading takes place simultaneously, the entire job may be completed in half the time that it would normally take by the conventional practice of first unloading the ship and then loading it.

Fig. 3 also shows facilities for tying two additional ships at the wharves so that little time may be lost between the loading un loading operations of the several Fuel tanks 55 may be installed in the two wharves to refuel the waiting ships. Possibly they may also be used to replenish the fuel supply of the several tractors used on the two wharves, assuming that the same grade of fuel is employed both by the ships engines and the tractor engines. If different grades of fuel are used, then separate tanks should be provided to serve the requirements both of the ships and of the tractors.

Referring now to the trailers and tractors which are used in connection with the present invention, it will be seen in the drawing and understood that each trailer as is a conventional trailer without modifications of any kind for the purposes of the present invention. The trailer may be twenty-eight feet in length, or thirty-feet, or thirty-two feet in length, its exact dimensions being unimportant insofar as the present invention is concerned, although the apparatus herein described is intended principally for the larger trailers which are generally used for interstate hauling rather than for the smaller trailers which are used in intra-city operations.

Tractor 4! is, however, somewhat unconventional. It has no fifth wheel for engaging the kingpin of the trailer. Instead, it has a platform 12 with a pair of upwardly projecting pins 43 fixed thereon and a bumper t l situated at for ward end of said platform. The platform is mounted on hydraulic lift members lib so that it may be raised to the position which it is shown to occupy in Fig. 7 or lowered to the position which it is shown to occupy in Fig. 6. Corners 4'6 at the back end of platform are beveled off or tapered for a purpose which will shortly become apparent.

The fiifth wheel which is necessary in the coupling of the tractor to the trailer is provided in the form of a portable fifth wheel assembly which constitutes a completely separate and independent entity, permanently connected neither to the tractor nor to the trailer. It comprises a box-like member or saddle 5! having a fifth wheel 52 pivotally mounted thereon. Saddle 5| hasa top, sides, and back, but it is open at the front or, stated differently, it has no front at all. A channel 54 is formed in its top portion, extending from front to rear, and open at the front and bottom. Corners 55 formed at the forward end of said channel are beveled or tapered complementarily to the bevel or taper 0f corners 46 of platform 42. The width of channel 54 slightly exceeds the width of I platform 42 and its length slightly exceeds the into said channel 54. The rearward movement draulic mechanism to its upper position as shown in Fig. '7. The saddle and its fifth wheel are now securely locked on the back of the tractor and the tractor may proceed to engage the trailer in the usual manner. Compressed air hose 5'5 may be hooked onto the trailer in the usual manner to actuate its brakes.

The loading and unloading operations take I place when the tractors are coupled to the trailers and they are backed onto the ship or pulled off the ship. See Fig. 8 and ramp 32a in Fig. 3. Referring now to Fig. 8, it will be seen that when a trailer is backed into a given compartment on board ship, its rear wheels ride up upon a ramp until the rear part of the body and'chassis of i ace-7,4531

l the trailer is disposed above a conveyor belt-Bi. At the same time, fifth wheel assembly 50 cc.- cupies a position immediately above a second conveyor belt 62. Two operations are now formed to deposit the trailer upon said conveyor belts: In the first place, the ramp B is lowered until the chassis or the trailer rests upon. conveyor 6!, and in the second place'platform 42 of the tractor is lowered until the saddle of the fifth wheel assembly rests upon conveyor 62. Further lowering of platform 42 will disengage itsv pins 43 from holes 56 of the saddle and the tractor will then be free to leave the trailer. Air hose should, of course, be disconnected.

The unloading process is simply the. reverse of the loading process. Thetractor movesinto position with respect to the fifth wheel assembly and platform 42 is caused to rise to engage the saddle of said fifth wheel assembly and to elevate it above the level of conveyor s2. Ramp 60 is also raised until the body of the trailer is elevated above the level of conveyor ill and the trailer is now free to move oil the ship. When the tractor and its trailer reach an appointed location on the wharf, wheels 68a of the trailer are lowered and the forward end of the trailer is lifted out of engagement with the fifth wheel assembly. The tractor may then depart from the trailer and carry withit: said 'fiitlrwheel assembly for use in engaging a second trailer loading it on board ship in the manner above described.

There are two ramps 69 for each trailer compartment on board ship. One of the rampsis for the purpose of elevating the back of the trailer to the level of the rear conveyor support ti. Thesecond ramp is for thepurpose or removing the trailer from the rear conveyor support.

A description or ramp til and its operating mechanism follows. (See Figs. 14 and 15.) It will be noted that each ramp Gil provided with a plurality of rollers 851 at its forward end and with a plurality of pivotally connected, inter nally threaded collars 66 at its back end. The rollers rest upon a depressed plate ill inthe deck plating es. lars 66: ride on a plurality of vertical screw shafts. 69. When these screw shafts are turned in a given direction, collars 66. move upwardly thereon and carry with them .the rear end or the ramp. The forward end or the ramp tends to roll backwardly on rollers 65 to the extent required. When the. screwv shafts are turned in the opposite direction, collars 65' are caused to moved downwardly and the back end or theramp is thereby lowered with said collars; The forward end of the ramp tends to move forwardly on said rollersBS.

The means whereby the screw shafts 83 are caused to rotate in either direction consists of a plurality of worm wheels. 10 which are af fixed to said screw shafts, a plurality of worms H which engagesaid worm wheels, a shaft 72 on which said worms are fixed, a bevel'gear i3 affixed to said shaft l2, 2. second bevel gear "id afiixed to a shaft. 15, and meshing with bevel gear 13, a gear box 16 to which shaft i5 is con-- nected, and a crank handle 77 which is also con-- nected to said gear box and which actuates the gears therein when it is worked in either direction. In other'words, when the crank handle is operated in one direction, the ramp will consumed to move upwardly onscrew shaftsBSl; and when the crank handle is operated in the opposite direction, said ramp will be caused to move downwardly on said shafts 69. Shaft I5 may besup-- The internally. threaded col-- ported on bulkhead 26 by means of suitable bear.- ings or brackets 18. Bearings 19, fastened to framework 89, may. be used to support screw shafts 68 in vertical positions on deck plating 68.

It will be noted in 8 that framework 80 last above mentioned, extends longitudinally and centrally of the ship and between the trailer compartments on the two sides of the ship. A walk or runway 8i is provided on said framework so that the crew of the ship may walk from one end of each compartment to the other without having to crawl underneath the trailers. A bulkhead door 82 is provided in each bulkhead 26 .to enable the crew to walk from compartment to compartment along the several catwalks 8|. Bulkhead doors 82 are, of course, water-tight for emergency purposes.

i will be understood that each trailer compartinent harbors a rear conveyor system Gland front conveyor system 62. The two rear convcyor systems 62' of each pair of transversely adjoining trailer compartments are supported on framework one on each side of catwalk Bl. (See Figs. 8, 12 and 13.) Framework to is elevated above the deck level and the upper run oi each these two conveyor systems is disposed 1 -evcrk and the lower run is disi below it, but still above the deck level. e s ecifically, framework lit-consists of a plurality of uprights Ella supporting a plurality of horizontal beards or girders 89h. Mounted on the or ders is a pair of tracks 85 on which These rollers are mounted on aid Ll inch serve as connecting pins for conve or sections die. A plurality of bearings 88 is provided on conveyor sections 62a and it will ize noted. that these bearings carry auxiliary rollers which are disposed at a higher level t an main rollers 86. As the conveyor belt moves 1 gitudinally of itself, its upper reach or run is supported by rollers lid and tracks 25. A pair of L.-shaped bars Bil is provided below horizontal Figs. 12 and 13.)

The front conveyor belt 62 is similar in construction to the rear conveyor belt [it except that it comprises a pair of conveyor belts 62a and respectively, which are joined by means of cross bars 620 which are H-shaped in cross section. Hence, conveyor 62 rec, ires two pair of tracks instead of the single pair 8t which con veyor 6! requires. Bearings Bil carryingauxiliary rollers 89 are fastened to the H-bearns 52c rather than to the conveyor sections Elia as is the case with conveyor system El. Hence only two L- beams ilil are required to support the auxiliary rollers 89, even though conveyor U2 is really a double conveyor having two belts 62a and 6221, respectively supported. by two pairs oftracksor rails 83. (See Figs. 10 andll.)

Front conveyor system 62 is mounted to extend below the level of deck plating G8. (See Fig. 8). It issupported by horizontal beaznsor girders 95, and it will '11; be noted that these horizontal beams or are support the deck itselfby means of i-i-ban More specifically, girders 85 carry track or '65 as Figs. 8 and 10 clearly show. Whena truck trailer is brought on board ship, its fii'th whe l assembly to is'depcsited upon H-bean1s It will be noted in 10 that the top surface of these beams is disposed at a slightly ligher level than the top surface of the deck. The reason for this will become apparent from an examination of Fig. 8. It will there be seen that one of the truck trailers is supported by means of a fifth wheel assembly or saddle 56 which projects over the side of conveyor 92. Were this conveyor not raised above the level of the deck, said fifth. wheel assembly, and more particularly its saddle member, would rest in part upon the conveyor and in part upon the deck, and hence it would be impossible to move the trailer from one location to another through the instrumentality of the two conveyor systems.

Fig. 16 shows in diagrammatic view how the conveyor systems are operated. A gear reduction motor tilt is connected by means of drive shaft HM and sprocket wheels 12 to the front conveyor belt 92, and a similar gear reduction motor its is connected by means of drive shaft H35, sprocket let, idler liil, and sprockets N38 to the rear conveyor belt t i. These two motor drives should be synchronized to cause the two belt systems to operate simultaneously and in unison.

Fig. 17 is a view of another wharf arrangement which may be employed in place of the arrangement shown in Fig. 3. Here one of the wharves is provided with a lower level H and with an upper level I I l, and the other wharf is provided with a lower level H2 and an upper level H3. A ramp l M provides access to upper level ill and a similar ramp I It provides access to the other upper level H3. Hence all of the trailers which are to be loaded upon the lower deck of the ship may be deployed upon lower levels Ill] and I I2, and all of the trailers which are to be loaded upon the upper deck of the ship may be deployed upon the upper levels Ill and H3, respectively.

It will be understood from the foregoing that what has hereinabove been described is a preferred form of the present invention, but slightly modified in Fig. 17, and that this preferred form may be modified in many Ways within the broad scope and spirit of the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. Apparatus for loading truck trailers upon a ship, moving the truck trailers from a loading to an unloading position on board ship, and unloading said truck trailers from the ship, said apparatus including a pair of conveyors on board ship, one for supporting the front end, and the other for supporting the back ends of the trailers and for moving them from one position to another, the ccnveyor for the backs of the trailers being disposed at an elevated level relative to the front conveyor, a ramp adjacent the rear conveyor to facilitate raising the back ends of the trailers to the level of the rear conveyor, said ramp being lowerable to deposit the back ends of the trailers upon said rear conveyor, and to remove all load from the trailer springs and wheels, said ramp being raisable under said wheels to elevate the back ends of the trailers above the level of the rear conveyor for removal therefrom and to re-transfer the load from said conveyor to said wheels and springs, a portable supporting member between the surface of the front conveyor and the front end of each trailer to support said front end of the trailer on said front conveyor, said portable supporting member being provided with a fifth wheel which engages the kingpin of the trailer.

2. Apparatus in accordance with claim 1, wherein a tractor is provided for engagement with the portable supporting member, said tractor being provided with raising and lowering means for raising the portable supporting member above the level of the front conveyor preparatory for deposit thereon and removal therefrom of said portable supporting member, and for lowering the supporting member upon said front conveyor.

HENRY D. CLEVELAND.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,440,065 Donnelly Dec. 26, 1922 1,611,419 Copcny Dec. 21, 1926 1,969,002 Gleichman Aug. 7, 1934 1,996,425 Ketel Apr. 2, 1935 2,121,181 Bayerl June 21, 1938 2,242,635 Whittelsey May 20, 1941 2,247,144 Baldwin June 24, 1941 2,439,232 Wyman Apr. 6, 1948 2,451,198 Burke Oct. 12, 1948 FOREIGN PATENTS Number Country Date 346,777 Great Britain Apr. 13, 1931