US3263777A

US3263777A - Lift truck carrier with a lost motion operator platform

Info

Publication number: US3263777A
Application number: US354658A
Authority: US
Inventors: Robichon Rene
Original assignee: F Hoffmann La Roche AG
Current assignee: F Hoffmann La Roche AG; Hoffmann La Roche Inc
Priority date: 1963-04-19
Filing date: 1964-03-25
Publication date: 1966-08-02
Anticipated expiration: 1983-08-02
Also published as: ES298898A1; NL6403464A; BE646524A; CH390793A; GB1061221A

Description

R. ROBICHON Aug. 2, 1966 LIFT TRUCK CARRIER WITH A LOST MOTION OPERATOR PLATFORM Filed March 25, 1964 5 Sheets-Sheet l 8 7 2 2 5 O A l 5 8 F J 2 w 2 I J O 6 6, 2 8 N. 6 4 6 l 4 0343 4 m o 4 L m m L I 0.1.KIPIL I I l I I I I I I I I l 9 r I. JK lurfiiillii 4 8 O Y .l 4 3 3 6 TI fi 7 3 1 3 I i m-U MH. 5 O d 9 3 5 5 l 2 '7 8 7 w n. 6

R. ROBICHON LIFT TRUCK CARRIER WITH A LOST MOTION OPERATOR PLATFORM Filed March 25, 1964 5 Sheets-Sheet 2 Aug. 2, 1966 3,263,777

LIFT TRUCK CARRIER WITH A LOST MOTION OPERATOR PLATFORM Filed March 25, 1964 R. ROBICHON 5 Sheets-Sheet 5 FIG. 3

United States Patent 3,263,777 LIFT TRUCK CARRIER WITH A LOST MOTION OPERATOR PLATFORM Ren Robichon, Birsfelden, Switzerland, assignor to Hoffmann-La Roche Inc., Nutley, N.J., a corporation of New Jersey Filed Mar. 25, 1964, Ser. No. 354,658 Claims priority, application Switzerland, Apr. 19, 1963,

5 Claims. (Cl. 187-9) The present invention is concerned with a fork-lift truck of the type which is provided with a fork-lift means.

Fork-lift trucks have widespread application today in every facet of commerce. When they are exclusively used out-of-doors or in uncovered storage areas, they are propelled by conventional internal combustion engines. When they are used exclusively in covered areas, they are provided generally with an accumulator, e.g. a storage battery, and are driven by means of electric motors which are energized by the said accumulator. Such driving systems are well known in the prior art and date back to the first use of electric trucks.

Heretofore, fork-lift trucks required that there be available for stacking purposes either empty or full pallets, containers and the like. If such were not available, the truckswould generally stand idle. Furthermore, such fork-lift trucks could not be utilized eflica-ciously in situations requiring the handling of small individual articles, e.g. such as those intended for direct use by the consumer or those which, due to their size, could be transmitted in large amounts in a relatively small package. Thus, forklift trucks have been found not to be particularly useful where it was desired to store such type materials in different designated compartments of shelving or Where it was desired to provide a myriad of different items of such a class in a pallet or container to satisfy a particular need, e.g. to fill the requirements of a customers order.

It is, thus, the object of the present invention to provide a fork-lift truck which can be used not only in the manner that conventional fork-lift trucks are commonly used, but also for utilization in warehousing small-type materials such as small. sized packets, polyethylene containers and the like, and which trucks are so-sized as to render them capable of being driven betweenoppositely disposed shelving disposed in close confronting relationship. This makes possible an easy transfer of diverse package goods, individual small-type articles and the. like from thepallets, containers and the like into. the areas of storage designated for suchcornmodities which may be situated at different levels and different places on the same floor and vice versa. 7

It is a further object of the present invention to provide a fork-lift truck suitable for operation by a, single individual and having means thereon which permit facile loading and unloading of. containers carried by the truck.

The fork-lift truck, according to the present invention, is thus characterized in that it is not only utilizable for the stacking or movement about of pallets, but is also extremely useful in the partial loading of material contained in a pallet, sequentially, into the various storage areas designated therefor, and, conversely, for the filling of a pallet or container to satisfy a particular customers requirement from various and diverse positions in the storage area. 7 This end is achieved by virtue of providing such fork-lift trucks with a moveable loading stand which is disposed in convenient relation to the platform on which the operator of the vehicle positions himself when driving the vehicle from one place to another. The loading stand for the loading and unloading of'a pallet is synchronized for movement with the raising of carrier arms so that the lifted pallet is situated at a good working level over the loading stand, and the convenient loading or unloading position of the pallet is lowermost at approximately the lowermost position of the loading stand.

Since the fork-lift truck, according to the present invention, is to be primarily utilized for the partial or piecemeal loading or unloading in closed storage area, to avoid the development of noxious fumes, it is preferably provided for this purpose with a driving system which is energized by electric means. Moreover, since the fork-lift truck of the present invention is intended to be utilized in connection with storage shelves which are generally in close confronting relation, it is evident that it must be of the smallest dimensions possible. Thus, the use of accumulators as the source of energy for the electric driving system is inconvenient due to space considerations.

To avoid the latter defect, the fork-lift truck of the present invention is energized from power supplied by a pick-up rail through a cable which is operatively connected to the fork-lift truck. The pick-up rail is of a type well known in the art.

The fork-lift truck of the present invention is particularly advantageous since it requires a minimum of space due to the slenderness of its construction. In a preferred embodiment, it is cm. in width.

The apparatus, according to the invention, is shown by way of example in the accompanying drawing in which FIGURE 1 is a side elevation view of the fork-lift truck in accordance with the present invention;

FIGURE 2 shows a plan view of the fork-lift truck in section taken along line IIII of FIGURE 1;

FIGURE 3 is a front elevation of the fork-lift truck in section taken along the line III-III of FIGURE 1.

The fork-lift truck, illustrated in the accompanying drawing, consists of a chassis 1 having mounted thereon

front wheels

2 and 3 and rear wheels 4 and 5. Rear wheel 4 is the drive wheel. A lifting and carrying. carniage comprises

carrier arms

6 and 7 and frame 8.

Carrier arms

6 and 7 are in spaced parallel relation and extend fowardly and horizontally from'frarne 8 to which they are integrally secured, said lifting and carrying oarriage 90 being adapted for vertical movement relative to chassis 1 in a manner more particularly made evident hereinafter. The chassis 1 includes upright channelshaped guide rails 9 and 10 which are positioned perpendicularly with respect to the base of the fork-lift truck in spaced parallel relation and are situated on the truck approximately equidistant from the said frontand

rear wheels

2, 3, 4 and 5. A loading stand 11 is provided for the fork-lift truck pallet unloader or loader to stand upon when effecting the transfer of material from a pallet or the like to a particular storage area designated for the material, or from a storage area to a pallet. Fixedly secured to the stand 11 are spaced supporting

arm

12 and 13 which extend at right angles and'upwardly from the plane of stand 11. Supporting

arms

12 and 13 are moveably mounted on guide rails 9 and 10 for movement in a vertical plane. Extending horizontally and rearwardly from guide rails 9 and His a platform 14 which comprises 'a part of the chassis. The front end of platform 14 extends between guide rails 9 and 10. This platform serves as a support for the fork-lift operator when moving about and permits easy access to the drive control indicated generally at 15, which regulates the motion of the fork-lift truck from one place to another and the movement of the carriage 90 in an upward or openabie housing indicated generally at 17, an electric motor 18 and a hydraulic pump 19. A U-shaped steering lever 20 is positioned on an axially rotatable shaft 21 arranged perpendicularly with respect to platform 14 and rotatably received in an opening thereof. Shaft 21 is fixedly secured at its lower end to a bearing housing 22 which houses the rear wheel 4. The bearing housing is axially rotatablle conjointly with shaft 21.

Chassis 1 is provided with two horizontally-extending rectangular parallel beams 23 and 24 which define an opening in which the fork-lift carriage 90 is adapted to be received as seen in dotted line in FIGURE 1. The rear ends of beams 23 and 24 are secured to the guide rails 9 and 10, and the sides thereof project transversely therefrom as best seen in FIGURE 3. The transverse projections permit the fork-lift truck operator to move from platform 14 to stand 11 under the most crowded conditions. Bifurcated portions are provided at the free ends of beams 23 and 24 to receive

front wheels

2 and 3 and, thus, form seats therefor. Guide rails 9 and 10 are reinforced at their lower ends by a U-shaped reinforcing member and at their upper ends by a tie beam 61. The

upright guide rails, the U-shaped reinforcing member and tie beam 61 combine to provide an upright rectangular frame of substantial strength.

As seen in FIGURE 2, drive control rests, in part, on platform 14 and includes the above-mentioned members 16 to 19. Positioned on cable drum 16 is a cable 25, the free end of which is connected to a pick-up bar (not shown). Cable is adapted to be rolled out of the cable drum on movement of the fork-lift truck away from the pick-up bar and rolled into the cable drum on movement-of the truck toward the pick-up bar. The withdrawal of cable 25 into cable drum 16 is eifected by a spring biasing means (not shown) associated with cable drum 16, according to known techniques. The cable 25 passes through a guide arm 26 which is held in place by an L-shaped bracket 60. L-shaped bracket 60 is securely fastened to guide rail 9. The end of cable 25 is connected to the pick-up head on the current pick-up mi l which can be positioned, for example, on the ceiling'of an enclosed storage area which may be a warehouse, a factory inventory depot and the like. The cable guide arm 26 has a cable receiving guide funnel 81 through which the cable runs. Within the guide funnel are mounted two freely rotatable rollers 80 which serve as a means for guiding the cable during the, movement thereof into and out of the cable drum.

Positioned beneath cable drum 16 is housing 17 in which the electrical control panel is situated. In an openable enclosure under the housing 17, there is situ-' ated electric motor 18. Motor 18 actuates hydraulic pump 19 arranged thereunder which energizes, as is later described, the means for raising and lowering the forklift carriage and the means for propelling the forklift trucktoandfro.

A bar 27, as seen in FIGURES 1 and 2, is'arranged adjacent driver platform 14 opposite to the drive control p 15 and serves as a safety device for the protection of an operator standing on platform 14. Provided within easy reach of the operator of the fork-lift truck, when standing on platform 14, is drive lever 28. Lever 28, on actuation in a desired direction, completes, under certain conditions, the operating system of the fork-lift truck which controls the forward and reverse drive. thereof. Slightly below lever 28 on the opposite side of the housing 17 is situated a master switch 29 (FIGURE 2) which controls, selectively, the feeding of current from the pick-up rail through the cable 25 into the operating system of the fork-lift truck. In order to protect against surreptitious use of the forkqlift truck, there is also provided a key ac- 4 tuated switch 30 as seen in FIGURE 2. The switch 30 is normally open and can only be closed by the insertion therein of the proper ,key means. As is conventionally the case, when the key operated switch is open, all the circuits associated with the fork-lift truck are broken. Such a key operated switch is known in the art and is not illustrated in detail in the accompanying drawing.

The fork-lift truck is propelled by a hydraulically actuated motor 31 (FIGURE 3) whose drive shaft is fixedly secured to the axle of drive wheel 4. Motor 31 is mounted on bearing housing 22 of the rear wheel 4 so that it is positioned on the side of drive wheel 4 which faces rear Wheel 5. As described above, shaft 21 and bearing housing 22 of drive wheel 4 are conjointly rotatable and are actuated for such rotation by the exertion of pressure in either direction on the U-shaped steering lever 20. Motor 31 and bearing housing 22 rotate about the axis of shaft 21 and the corresponding axis of wheel 4 which is perpendicular to the plane of the surface on which the fork-lift truck is positioned. U-shaped lever 20 is rotatable only in either direction from the position thereof shown in FIGURES 1 and 2. Thus, rotational motion of drive wheel 4, bearing housing 22 and motor 31 about their vertical axes is limited to It is to he understood that platform 14 can be extended to a point whereat motor 31, at its limit of movement about the axis of drive wheel 4, does not project from under platform 14 at any time during such rotational movement. Alternatively, the fork-lift truck can be provided with a conventional bumper means, e.g. a rubber disk, a bar or the like which is positioned adjacent the rear edge of platform 14, at such a point whereat motor 31 is permitted to rotate freely within its limits of rotational movement with-out fear of it contacting an object closely adjacent to the truck. Thus, the danger of damage to this piece of equipment can be minimized.

Pressure cylinder 32 which is secured to the frame of the chassis between guide rails 9 and 10 effects the raising and lowering of the carriage 90. Associated with pressure cylinder 32 is a piston 33, which piston is raised perpendicularly by the hydraulic pressure supplied by hydraulic pump 19. The upper end of the piston 33 has a portion which protrudes from pressure cylinder 32 at all times. Piston 33 carries a freely rotatable chain roller 34 attached thereto by pintle 32a. Movably mounted on chain roller 34 is a chain 35. The chain 35 is secured at one end 36 to the drive control housing and at its other end 37 to frame 8 which is integral with

carrier arms

6 and 7. When piston 33 is lowered vertically =by hydraulic pressure, chain 35 moves over chain roller 34 in a counterclockwise direction. Such movement of chain 35 in a counterclockwise direction permits frame 8 to be moved vertically downwardly under the influence of gravity from the raised position thereof shown in FIGURE 1 to the lowermost position thereof shown in dotted line in FIGURE 1. When the piston 33 is' moved upwardly to the raised position thereof shown in FIGURE 1, it efiects movement of chain 35 over roller 34 in a clockwise direction. Chain 35, on movement in a clockwise direction, causes frame 8 to move in an upwardly direction. It is thus apparent, that on actuation of piston 33, any load which iscarried by-

carrier arms

6 and 7 can be raised or lowered depending upon the need of the operator of the truck.

The vertical movement of frame 8 is controlled by runner means provided by the channel-shaped configuration of guide rails 9 and 10. Such channel-shaped guide rails are arranged on the fork-lift truck so that their webbed faces are on the outer sides of the upright rectangular frame of which they, tiebeam 61 and the U- sh-aped reinforcing member form a part. Guide wheels 40 are received in the channel-shaped openings of guide rails 9 and 10. Supporting strips 38 and 39 are situatedbetween guide rails 9 and 10 and are, respectively, in

close confronting relation thereto.

Strips

38 and 39 each carry two of the last-mentioned guide wheels 40 in spaced planer relationship and are integrally fastened at right angles to frame 8. Guide wheels 40, due to their being positioned in the channel-shaped portions of guide rails 9 and .10, function to operatively connect the carriage 90 to the guide rails for vertical sliding movement and against transverse movement relative thereto.

As described above, a loading stand 11 is arranged for movement within a rectangular opening in frame 8. Stand 11 is operatively supported by guide rails 9 and (10 for lost-motion relative to frame 8 in the following manner. Loading stand 11 is provided, on the side thereof facing guide rails 9 and :10, as best seen in FIG- URE 2, with upright planer bars 12 and 113.

Bars

12 and 13 carry perpendicularly disposed thereto at their upper end, supports 44 and 45. The supports 44 and 45 each fixedly carry at their outer ends, roller means 48. The sides of

supports

44 and 45, in confronting relation with roller means 48, are juxtaposed to the webs of guide rails 9 and 10 so that roller means 48 bear upon the rearwardly positioned sides of guide rails 9 and 10. Disposed downwardly on

bars

12 and 13 from the

supports

44 and 45, are

supports

46 and 47 which also extend rearwardly at right angles from

bars

12 and 13.

Supports

46 and 47 have secured thereto by a pintle means

rollers

50 and 51.

Rollers

50 and 51 bear upon the sides of guide rails 9 and 10 opposite to the sides that roller means 48 bear against and thus combine with roller means 48 to maintain loading stand 11 against transverse movement while permitting sliding movement thereof in a vertical direction along the guide rails.

Loading stand 11 'has no separate driving means, but it is connected by lost-motion means to frame 8 and

arms

6 and 7. To impart movement to loading stand 11, there is provided on each of iron bars 12 and 13,

angle plates

52 and 53, respectively.

Angle plates

52 and 53 extend from bars 112 and 13 over the upper edge of frame 8. Thus, the angle plates always lie over frame 8 and, accordingly, are positioned in the path of upward movement thereof.

Loading stand 11 is elevated when frame 8 is moved upwardly. The angle plates are positioned on iron bars 12 and 13 at a height that only permits movement of loading stand 11 in an upward direction when the surface of a pallet to be unloaded lies approximately 80 c.m. higher than the base of the loading stand 11, i.e. at approximately a good working level above the loading stand. When lowering frame 8 from an upper position, the loading stand 11 reaches its lowermost position on the fork-lift truck before frame '8 reaches the lowermost position of its movement.

The lowermost position of loading stand 11 is determined by

projections

54 and 55 which are positioned on guide rails 9 and 10 on the web side thereof as seen in FIGURE 3. Such projections project into the path of vertical movement of

supports

46 and 47 on bars 12 and '13. The

projections

54 and 55 and the

supports

46 and 47 therefore combine to serve as means to limit downward movement of stand 11.

As is apparent from the above, when frame 8 is actuated in an upward direction by motion imparted thereto via piston 33, after a portion of such upward movement is completed, it engages

angle plates

52 and 53. Frame '8, thereafter, carries loading stand 11 with it as it continues its upward movement toward a desired position. When frame 8 is actuated in a downward direction from such desired position, stand 11 moves downwardly therewith until

supports

46 and 47 engage

projections

54 and 55 positioned in the path of movement thereof. On

supports

46 and 47 abutting

projections

54 and 55, further downward movement of stand 11 is precluded and frame 8 continues the movement thereof to its lowermost position alone.

On bar 12, within easy reach of an individual standing on the loading stand 11 is a push-button switch 59 having 3 push-button members for control, respectively, of upward movement *(Up), of downward movement '(Down) and the inoperative condition (Off). This switch is operatively connected to frame 8 and functions as the means for controlling the movement of frame 8 to a desired level.

According to the foregoing description, the drive lever 28 functions to actuate the system which imparts propelling motion to the fork-lift truck. The push-button switch 59 functions to actuate the system which is responsible for the vertical movement of carriage and the stand 11 operatively connected thereto. The propelling motion is controlled by motor 31 and the raising and lowering of the carriage 90 is controlled by the hydraulic pressure provided by motor 18 through piston 33 and chain 35.

Before any electrical energi-zation of any of the mechanisms of the fork-lift truck can be effected, it is essential that key switch 30 be in closed condition. On insertion of the proper key in the cylinder of the key switch 30 and movement thereof to the operative On position, the fork-lift truck is ready for operation. The circuit to electrical motor 18 can then be completed on movement of main switch 29 to the On position. Motor 18 actuates the hydraulic pump 19. Hydraulic pressure produced by the hydraulic pump acts so long as the carriage 90 is not set in motion so that the unillustrated pressure release valve opens and the pressure fluid circulates in a closed system. Actuation of the drive lever 28 from the Off position into positions which will result in the forward or backward movement of the fork-lift truck opens an electrical control valve (not shown), according to the procedures known in the art, which conducts the pressure fluid in one or the other direction through the motor 31. Drive wheel 4 is then rotated in either the forward or the backward direction of drive. By turning the drive lever 28 into the Off position, the actuated valve is again closed and the fork-lift truck comes to rest. The electric push-button switch 59, as is noted above, when actuated, results in the raising or lowering of carriage 90. On actuation of the Up push-button, pressure fluid enters cylinder 32 through a valve (not shown) in accordance with conventional techniques and raises the piston 33 by fluid means until such raising is discontinued on the frame 8 reaching the limit of its upward movement and/ or by actuation of the push-button marked Off. Depression of frame 8 is, of course, initiated by actuation of the push-button marked Down. Means, not shown, are provided to open the circuit of the system controlling upward movement of frame '8 on the latter, reaching the limit of upward movement thereof. Such means are well known in the art.

In FIGURE 1, the loading stand 11 is shown in dotted lines in its lowermost position. In this position of the loading stand 11, the operator can step from driver platform 14 onto the base of loading stand 11 which is situated at approximately the same height as driver platform 14. For convenience, plate 62, positioned about the loading stand 11, can be reduced in dimension on one side, preferably the side opposite that which safety device 27 is positioned, to facilitate entry onto the loading stand 11, e.g. the plate 62 can be only 5 to 10 cm. high.

As is evident from the above, the fork-lift truck can be eflicaciously made to perform its intended function by a single individual. This is irrespective of the amount of loading or unloading that is required, or the heights at which certain specified material have to be put. For example, the operator of the vehicle first initiates movement of the truck to a designated storage area. When such area is reached, he merely steps over to the load-ing stand 11 and, when appropriate, elevates the carriage 90 to the desired height.

It is however, of course, understood that when it is desired to rapidly gather various and diverse articles from storage compartments, two individuals can efi'icaciously effect this end. For instance, one of thesaid individuals will control the propelling motion of the fork-lift truck and the other individual will position himself on the loading stand 11. Thereafter, the driver of the vehicle will proceed through the storage area to the designated stops. The individual positioned on the loading stand 11 will move the fork-lift mechanism up and down and remove from the storage area the materials desired and place the same in the pallet carried on the

carrier arms

6 and 7. It can be readily seen that the fork-lift truck of the present invention is particularly desirable in this regard since it facilitates the rapid filling of desired needs with a minimum of effort. Heretofore, in order to fill a need requiring many diverse and often times small articles from different areas of storage, it was necessary to move about often times with the aid of a cumbersome ladder and gather each item separately. With the present invention, an individual can ride about with little or no inconvenience on stand 11 and, rapidly, without the necessity of ladders or other mounting means and their attendant dangers of injury to workmen, particularly where safety is sacrificed for speed, fill varied and diverse needs in an efficient and safe manner.

Safety pedals, sometimes called dead mans pedals, are provided in the base of the loading stand 11, as illustrated in FIGURES 1 to 3. Such pedals are operatively connected to switch means which are in series with a circuit which includes the push-button switch 59. Thus, when these pedals are not depressed, thereby closing the first-mentioned switch means, carriage 90'can neither be raised nor lowered. Only when the individual standing on the loading stand 11 has both feet on such pedals can the raising or lowering of carriage 90 be effected. It is readily apparent that such a feature imparts to the fork lift device of the present invention an effective way of assuring, as much as is possible, the safety of the operator of the fork-lift truck.

More particularly, the so-called dead mans pedal assures that 'a person who is stepping onto the stand 11 does not suffer severe injury by an inadvertent closing of one of the push-button switches on switch 59. The loading stand 11 can be provided, if desired, with a surrounding screen which may be in the nature of 30 to 40 cm. high and thus another safety feature is provided which serves to avoid injury to an alighter who might attempt to mount the loading stand 11 when the system controlling frame 8 is in operation. It is only constructed with a lowered side, as described above, in order to render stand 11 easily accessible to the person stepping from driver platform 14 to loading stand 11. The manner in which the so-called

dead mans pedals

56 and 57 are operatively connected to the push-button switch 59-circuit is not shown since such structural designs are well known in the art. I The electrical association between the electrical switch 59 and the lever switch 28 or any of the other switches and the electrical valves and the switch panel, respectively, are also not shown because they are also considered to be well known in the art.v This applies with equal eflicacy to the construction of the hydraulic pump and the motor 31 and to the connecting conduits associated therewith.

The carrier arms 6 and 1 of the carriage 90 are illustrated by dotted lines on the elevated frame 8 in FIGURE 3. The carrier arms are not, themselves, visible in the section shown in FIGURE 3, but are included therein for the purpose of clarification. I

Iclaim; H I 1. A fork-lift truck comprising controls for driving the truck positioned on the rear portion ofthe truck, a load handling frame positioned on the front portion of the;

truck, a vertical mast disposed between the driving controls and the load-handling frame, said load-handling frame being mounted for vertical motion on said mast and extending therefrom toward the front portion of the truck,

said load-handling frame comprising an open framework adjacent said mast and a load carrying portion secured to said framework and extending outwardly from the foremost portion of the framework, an operator platform on the front portion of the truck adjacent the load-handling frame and mounted for vertical motion on the said vertical mast, and a lost-motion connection between the said load handling frame and the said operator platform whereby the frame maybe moved completely above the operator platform before causing vertical motion thereof.

2. A fork-lift truck as defined in claim 1 wherein the said operator platform is slideably received in the opening in said open framework in said load handling frame.

3. Packing, unloading and lifting means for use on an industrial truck 'which truck includes a motor means and a vertical mast, said unloading and lifting means comprising a load handling frame and an operator platform, said load handling frame being mounted for vertical motion on said vertical mast and including an open framework adjacent said mast and a load carrying portion secured to said framework and extending outwardly from the foremost portionof the framework, means mounting the load handling frame for movement in a vertical direction on the vertical mast, said operator platform being slideably received in the opening in said open framework, means mounting said operator platform on said vertical mast for movement in a vertical direction, said last-mentioned means comprising a supporting means extending upwardly from the operators platform, a lost-motion connection between the load handling frame and said operator platform, said lost-motion connection being adopted to permit movement of the load-handling frame relative to the operator platformfor a portion of the capable vertical movement of the load-handling frame but precluding relative vertical movement of said operator platform and said load-handling frame for the remainder of the capable vertical movement of said load-handling frame, said lost-motion connection comprising a projecting means rigidly secured to said supporting means, said projecting means being disposed in the path of upward movement of the said framework, said lost-motion connection further comprising a project-ing means engaging portion on said framework, the last-mentioned portion being spaced from said projecting means when the framework is in its lowermost portion of vertical movement, said portion on said framework being adopted to engage said projecting means on movement of said framework upwardly from its lowermost position, such engagement resulting in the upward movement of said operator platform, said operator platform being disposed completely below said framework when said projecting means and said projecting means engaging pontion are engaged.

4. .In va fork-lift truck having a propelling means, a driving platform situated at the rear portion of said truck, means adjacent said driving platform for controlling the direction of movement of said truck, a vertical mast, a load-handling frame mounted for vertical motion on the mast, said load-handling frame comprising an open framework adjacent said mast and a load carrying portion secured to said framework and extending outwardly from.

the foremost portion. of the framework, an operator platform adjacent said load-handling frame and mounted for vertical motion on said mast, a lost-motion connection between the load-handling frame and said operator platform whereby movement of said frame in a vertical direction results in a corresponding movement of said operator platform in a co'rrsponding direction within defined limits between a lowermost position and an uppermost position, transverse means extending in a horizontal plane along one side of said truck from the driving platform to aposition adjacent the operator platform when in its lowermost position of vertical movement, said transverse means having an exposed, free, planar upper surface, said surfaee constituting a walkway to permit move- 9 about the outside of the vertical mast without alighting from the fork-lift truck.

5. An apparatus as defined in claim 4 wherein the operator platform is slideably received in the opening in said open framework.

References Cited by the Examiner UNITED STATES PATENTS 2,496,399 2/1950 Lesser 1879 10 OTHER REFERENCES Chicago Tramrail Corporation Bulletin SR-101, Stack-Rak Application, 15 pages (only page 6 is relied on), received May 22, 1953.

Chicago Tramrail Corporation Bulletin TRC-101, Trak-Rak, 201pages (only page 6 is relied on), received May 18, 1955.

GERALD M. FORLENZA, Primary Examiner.

5/1960 Miller 187--9 X 10 R. BQJOHNSON, Assistant Examiner.

Claims

1. A FORK-LIFT TRUCK COMPRISING CONTROLS FOR DRIVING THE TRUCK POSITIONED ON THE REAR PORTION OF THE TRUCK, A LOAD HANDLING FRAME POSITIONED ON THE FRONT PORTION OF THE TRUCK, A VERTICAL MAST DISPOSED BETWEEN THE DRIVING CONTROLS AND THE LOAD-HANDLING FRAME, SAID LOAD-HANDLING FRAME BEING MOUNTED FOR VERTICAL MOTION ON SAID MAST AND EXTENDING THEREFROM TOWARD THE FRONT PORTION OF THE TRUCK, SAID LOAD-HANDLING FRAME COMPRISING AN OPEN FRAMEWORK ADJACENT SAID MAST AND A LOAD CARRYING PORTION SECURED TO SAID FRAMEWORK AND EXTENDING OUTWARDLY FROM THE FOREMOST PORTION OF THE FRAMEWORK, AN OPERATOR PLATFORM ON THE FRONT PORTION OF THE TRUCK ADJACENT THE LOAD-HANDLING FRAME AND MOUNTED FOR VERTICAL MOTION ON THE SAID VERTICAL MAST, AND A LOST-MOTION CONNECTION BETWEEN THE SAID LOAD HANDLING FRAME AND THE SAID OPERATOR PLATFORM WHEREBY THE FRAME MAY BE MOVED COMPLETELY ABOVE THE OPERATOR PLATFORM BEFORE CAUSING VERTICAL MOTION THEREOF.