US2869744A

US2869744A - Tilting assembly for lift trucks

Info

Publication number: US2869744A
Application number: US605060A
Authority: US
Inventors: Kagel Hans
Original assignee: Vereinigte Westdeutsche Waggonfabriken AG
Current assignee: Vereinigte Westdeutsche Waggonfabriken AG
Priority date: 1955-08-24
Filing date: 1956-08-20
Publication date: 1959-01-20
Anticipated expiration: 1976-01-20

Description

Jan. 20, 1959 H. KAGEL TILTING ASSEMBLY FOR LIFT TRUCKS 4 Sheets-Sheet 1 Filed Aug. 20, 1956 Jan. 20, 1959 H. KAGEL 2,869,744

TILTING ASSEMBLY FOR LIFT TRUCKS Filed Aug. 20, 1956 I 4 Sheets-Sheet 2 Jan. 20, 1959 i'-l. KAGEL TILTING ASSEMBLY FOR LIFT TRUCKS 4 Sheets-Sheet a I Filed Aug. 20, 1956 Jan. 20, 1959 H. KAGEL TILTING ASSEMBLY FOR LIFT TRUCKS I 4 Sheets-Sheet 4 Filed Aug. 20, 1956 United States arena TILTING ASSEMBLY FOR. LIFE TRUCKS Hans.,Kagel, Berg-ischrGladhach, Germany, assignor to VereinigteWestdeutsche Waggonfabriken,Aktiengesellschaft, Koln neutz, Qerrnany ,ApplicationlAugust 20; 1956, Serial No. 605,060

Claims priority, applicatiori Germany Augustll, 1955 SfiGlaims. Cl."214672) .The present; invention relates to a. lifttruck. equipped with a ifter slide which is-guided on a substantially vertical post-connected to the vehicle frame and which carries the load carrier proper as for instance; a fork or a mandrel.

Lift trucks are; known in which the. guiding post is tiltable aboutaashatt arr nged horizontally: atJthe lower end ot saidypost andflextending; transverse tonthe driving di rection of the vehicle. I thi way, it is possible forpurnoses of oadinqand unloading-t place thefork-in. a downwardly inclinedposition, whereas. during driving-it. is possible to place the fork. in an upwardlyinclinedpposition. to thereby prevent, the good-s to be transnorted; fromfalling off during the braking operation 1 or, When the vehicle: encounters. a sudden push. l-Iowever, this pivotal connection of the guiding post with the vehicle frame brin s. about considerable difficulticsfrom a. structural. standpoint due to the high-load ac ingupon said pivotal connection; In addi-tion thereto the, said pivotal. connection is. subject toa relatively quick wean: Due to these difficulties. especiah y. lftt l l inc eanhas taken place, the above mentioned ,knownpiyotal connection does notassurethe desired rigidity betweenthe guiding post. and thevehicle frame. Inadditiontheretorthe pivotal connectionof the guiding post to the. vehicle frame. requires the interposition of hose connections; or. other flexible fluidi conveying means between the hydraulic lifting device in'the guiding post and the fluid source on; the vehicle.

. To overcome the above mentioned drawbacks, lift trucks have beendesicned n which the guiding. mast is rigidly connected to the, vehicle frame; and in. which the fork. or the likeis always,directed upwardly away from the,vehicle. This .tyneoff-lizft. trucks, however. has thedrawback that the loadin and unloading is relatively difficult. Therefore, it hasbeensugtzestedso to desi n the guiding means-on themed-post that thelifterslide and principal tasks-of such lifttruckis'possible under-certain difiticulties only.

It is, therefore. an obicct of, the present invention to provide a lift truck which will overcometheabove mentioned drawbacks.

It; is another object of; this invention toprovide a liftv truck which will make it possible to tilt the. load carrier at any-desired level without encountering the difficulties of; the, .lieretofore, knownliit trucks.

ltjs still another object of this. invention-toprovide By making the. post, tiltable in 2,869,744 Patented Jan. 20, 1959 a lift truck of the type, set forth in the preceding, paragraph in which the tilting position of the load. carriermay be varied. t

Still another object of this invention consists in the provisionof a lift truck with a load carriertiltable at any desired level, in which the tilting operation is effected by a lifting cylinder pistonv system which is simplein constructicn and easily accessible.

These andother objects and advantages of theinvention will appear more clearly from. the followingspecid cation in connection withthe accompanying drawings in which: 1

Fig. 1 illustrates a lift truck according to the present invention with the. load carrier slightly lifted off from the ground.

Fig.2 shows thelift truck of Fig. 1 with the. loadcan rier in picking up position.

Fig. 3 is a top view ofFig. 1.

.Fig. 4 shows asom-ewhat modified arrangement ofa lift truck with the load. carrier in picking up position.

Fig. 5 is a top view of the lifttruck of,'Fig 4.

Fig. dis a diagrammatic, illustration ofja. hydraulic circuit for use inconnecti'on with the lift truck. according to the invention.

General arrangement The problem underlying thepresent invention namely the creation of a lifttruck with a,load 1carrier adapted to vention by fixedly connectingtlie guidingpost in a man.-

er known per se tothe vehiclebody, while makingthe entire vehicle body together with the guiding posit. tilta ble about the axis or haft of the wheel set" adjacent the guiding post. To this end; the vehicle body is displace.- able substantially in vertical direction relative to the wheel set remote from saijdguiding post, while a lifting device is provided between said last mentioned wheel set and the vehicle body. The term vehicle body is intended to be constructed broadly and to comprise any superstructure of the vehicle. The vehicle body may, for instance, consist of a frame to which the individual units such as guiding post, the wheel setadjacent' said guiding post, motor, transmission, etc. are connected individually or in groups. However, the vehicle body may also be so desi ned that theindividual units are pro-vided with self-supporting casingsand-are-flanged toeach other in a positive manner. r

Inasmuch as in most-instances a hydraulic lifting device will be employed for the load carrier, it is advantageous the load about the tilting axisof the vehicle. is higher;

than the oppositely directed'torque of'the weight of the vehicle. in such an instance, the ve icl'e body is pulled downwardly by the double acting lifting deviceat the wheel set remote from the load carrierwhich last tioned wheel set may be provided with additional counten weights.

The wheel set remote from the guiding post may, for instance, be guided in a substantially. vertical guide ofth o vehicle body or it may be linked.- tothe-vehicle-body by means of a substantially horizontal levcreretending in-th'c longitudinal direction; of the vehicle.

Structural arrangement Referring now to the drawings in detail and Figs. 1 to i wheel set 5. The engine 2 is furthermore adapted through the intervention of gears 6 and 7 to drive a hydraulic pump 8 for feeding the two

hydraulic cylinders

9 and 10. The steering mechanism 11 and the drivers seat 12 are connected to the vehicle body 1. Fixedly connected to the front side of the vehicle body 1 by means of screws 13 is a guiding post 14 for the lifter slide 15. The lifter slide 15 carries a fork 16. Due to the fact that the drivers seat 12 is connected to the vehicle body 1, it will tilt together with the tilting movement of the vehicle body which tilting movement will be described furtherbelow. This fact that the drivers seat tilts together with the vehicle body gives the operator a sure indication as to the inclined position of the vehicle so that if the vehicle body should be in lifted position, the inclined position of the drivers seat will always remind the driver prior to causing the vehicle to move, to lower the vehicle body. The rear wheel set 17 is in conformity with the showing of Fig. 3 linked to the vehicle frame 1 by

levers

18 and 19 respectively on both sides of the chassis. These

levers

18 and 19 extend substantially horizontally in the longitudinal direction of the vehicle. The pivots 20 and 21 of the

levers

18 and 19 are located as closely as possible to the axis of the wheel set 5. The pivots 20 and 21 are so arranged that the distances a (Figs. 1 and 2) of said pivots 20 and 21 from the plane AB through the axes of the two Wheel sets and 17 measured perpendicular from said plane equal each other when the vehicle body is completely lowered and when the vehicle body is completely lifted. In this way, the change in the wheel base, i. e. in the distance between the wheel sets 5 and 17 during the tilting movement of the vehicle body 1 about its front wheel set 5 will be reduced to a minimum. If the pivots 20, 21 would be located on the axis of the wheel set 5, no change in the wheel base would occur during the tilting movement of the vehicle base 1. Such an arrangement, however, would due to lack of space on the wheel set 5 which is being driven cause considerable difficulties from the design standpoint. I

The rear ends of the two

levers

18 and 19 have co nected thereto a counterweight 22, while a further counterweight 23 is connected to the rear end of the vehicle body 1.

Interposed between the wheel set 17 andthe vehicle body 1 is a hydraulic cylinder piston system by means of which the vehicle body 1 can be tilted about the axis of the wheel set 5 thereby causing the fork 16 to change its inclined position. The hydraulic cylinder piston sys tem 10 is designed as a double acting cylinder piston system so that it can press as well as pull. A pulling operation of the cylinder piston system 10 may be necessary when'it is intended to tilt back the vehicle body after the fork 16 has been loaded while the vehicle body 1 was in tilted up position. When the torque of the load on fork 16 about the front wheel set 5 is higher than the torque of the weight of the vehicle body 1 and the counterweight 23, it is necessary that the vehicle body 1 be pulled downwardly by the cylinder piston system 10. The arrangement of at least a portion of the counterweight on the

levers

18 and 19 yields a low position of the center of gravity of the entire vehicle which fact is favorable for the driving properties and the stability of the truck. Furthermore, in :this instance it is not necessary to lift the counterweight by the cylinder-piston system It).

The vertical movement of the lifter slide which is guided by guiding

rollers

24 and 25 on the post 14 is effected by thehydraulic cy1inder'9 through the intervention of a chain 26 which passes over a return roller 27 mounted on the post 14.

The embodiment of Figs. 4 and 5 differs from that of Figs. 1 to 3 primarily in that the total counterweight 28 is connected to the rear wheel set 17. The vehicle body 1 is guided relative to the rear wheel set 17 by dovetail shaped vertical guiding means 29 and 30. The remaining parts corresponding to those of the embodiment shown in Figs. 1 to 3 are designated with the same reference numerals as in Figs. 1 to 3.

As has been clearly shown in Fig. 6, the driving system and the hydraulic system for the vehicle comprises an internal combustion engine 2. This engine drives a hydrostatic pump 3 through a clutch 31 while

conduits

32 and 33 lead from said pump 3 to a control valve 34. The control valve 34 controls the supply of pressure oil through

conduits

36, 37, 38, and 39 to the drive motors 4' and 35. The return conduit from control valve 34 to the oil reservoir 40 is designated with the reference nu meral 41. The hydrostatic pump draws oil from the oil reservoir 40 through conduit 42.

The internal combustion engine 2 additionally drives through gears 6 and 7 a hydraulic pump 8 which draws oil from the oil reservoir 40 through a conduit 43, The pressure oil conveyed by the hydraulic pump 8 to the control valve 45 through conduit 44 may selectively be conveyed through a conduit 46 to the master cylinder 9 for the fork 16 or through the conduit 47 or 48 to the hydraulic cylinder piston system 10 for purposes of tilting the vehicle body. Depending on whether pressure oil is conveyed to the cylinder piston system 10 through conduit 47 or conduit 48, the cylinder piston System10 will press the vehicle body 1 upwardly or pull it down wardly respectively.

As will be evident from the foregoing description, the arrangement according to the present invention overcomes all difiiculties heretofore encountered with lift trucks having a tiltable guiding post. By tilting the entire vehicle body in conformity with the present invention including the guiding post, the load carrier may at any desired level be moved into any desired inclined position. Fur

thermore, the arrangement according to the invention also makes it possible to design the steering body, i. e. the body'of the wheel set remote from the guiding post, as a one-piece cast body.

It will also be obvious from the foregoing description that the master cylinder piston system is of a simple construction and is easily accessible as to its entirety and also as to its connection to the vehicle body at the rear end thereof inasmuch as at this place neither the vehicle body itself nor other elements within the vehicle body interfere with the accessibility.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In combination in a lift truck having a vehicle body: a first axle with a pair of wheels, said vehicle body being pivotally connected to said first axle so as to be tiltable about the same, an upwardly extending post fixedly connected to said vehicle body near said first pair of wheels, at lifter slide movably mounted on said post and including load-supporting means, a second axle spaced from said first axle in longitudinal direction of said truck and provided with a second pair of wheels, link arm means pivotally linking said rear axle to said vehicle body near said first axle, and fluid operable cylinder piston means linked to said second axle and said vehicle body for selectively tilting said vehicle body about said first axle from a lowered position into a maximum lifted position and vice versa, said link arm means when said vehicle body is in its lowered position forming with the plane passing through the axes of said two axles an angle which is substantially equal to the angle formed by said plane with said link arm means when said vehicle body is in its maximum lifted position.

2. In combination in a lift truck having a vehicle body: a first axle with a pair of wheels, said vehicle body being pivotally connected to said first axle so as to be tiltable about the same, an upwardly extending post fixedly connected to said vehicle body near said first pair of wheels, a lifter slide movably mounted on said post and including load-supporting means, a second axle spaced from said first axle in longitudinal direction of said truck and provided with a second pair of wheels, link means pivotally linking said rear axle to said vehicle body near said first axle, and fluid operable cylinder piston means linked to said second axle and said vehicle body for selectively tilting said vehicle body from its normal position into a lifted position and vice versa, said load-supporting means having its load-supporting surface pointing upwardly when said vehicle body is in its normal position and having its load-supporting surface pointing downwardly with the front end thereof close to the ground when said vehicle body is in its lifted position.

3. In combination in a lift truck having a vehicle body: a first axle with a pair of wheels, said vehicle body being pivotally connected to said first axle so as to be tiltable about the same, an upwardly extending post fixedly connected to said vehicle body near said first pair of wheels, a lifter slide movably mounted on said post and including load-supporting means, a second axle spaced from sad first axle in longitudinal direction of said truck and provided with a second pair of wheels, link means pivotally linking said rear axle to said vehicle body near said first axle, a first counterweight connected to said second axle, a second counterweight connected to that end of the vehicle body which is adjacent said second axle, and fluid operable cylinder piston means linked to said second axle and said vehicle body for selectively tilting said vehicle body about said first axle.

4. In combination in a lift truck having a vehicle body: a first axle with a pair of wheels, said vehicle body being pivotally connected to said first axle so as to be tiltable about the same, an upwardly extending post fixedly connected to said vehicle body near said first pair of wheels, a lifter slide movably mounted on said post and including load-supporting means, a second axle spaced from said first axle in longitudinal direction of said truck and provided with a second pair of wheels, link means pivotally linking said rear axle to said vehicle body near said first axle, a counterweight representing the total counterweight and being connected to said second axle, and fluid operable cylinder piston means linked to said second axle and said vehicle body for selectively tilting said vehicle body about said first axle.

5. In combination in a lift truck having a vehicle body: a first axle with a pair of wheels, said vehicle body being pivotally connected to said first axle so as to be tiltable about the same, an upwardly extending post fixedly connected to said vehicle body near said first pair of wheels, a lifter slide movably mounted on said post and including load-supporting means, a second axle spaced from said first axle in longitudinal direction of said truck and provided with a second pair of wheels, link means pivotally linking said rear axle to said vehicle body near said first axle, and fluid operable cylinder piston means interposed between and operatively connected to said link means and said body for selectively tilting said vehicle body from its normal position into a lifted position and vice versa, said load-supporting means having its load-supporting surface pointing upwardly when said vehicle body is in its normal position and having its load-supporting surface pointing downwardly with the front end thereof close to the ground when said vehicle body is in its lifted position.

References Cited in the file of this: patent UNITED STATES PATENTS 2,439,139 LeTourneau Apr. 6, 1948 2,623,653 Frarnhein Dec. 30, 1952 2,684,165 Hill July 20, 1954 2,693,250 Barrett Nov. 2, 1954