US2704615A

US2704615A - Load-handling truck

Info

Publication number: US2704615A
Authority: US
Publication date: 1955-03-22
Anticipated expiration: 1972-03-22

Description

A. S. STOKES ET AL LOAD-HANDLING TRUCK March 22, 1955 4 Sheets-Sheet 1 Filed Feb. 28. 1952 INVENTORS 8) 2 Q a R Q ATTORNEY 70M primes/v0 JOHN FUBE/FTMF0Q/VFLD,

March 22, 1955 s, STQKES ETAL 2,704,615

LOAD-HANDLING TRUCK Filed Feb. 28. 1952 4 Sheets-Sheet 2 A TTORNE) March 22, 1955 A. s. STOKES ET AL LOAD-HANDLING TRUCK 4 Sheets-Sheet 3 Filed Feb. 28. 1952 5 m 0 V; T W& N M 4 Y T M F M M my 5% Z5 Y N m R W W fig March 22, 1955 Filed Feb. 28, 1952 A. S. STOKES ET AL LOAD-HANDLING TRUCK 4 Sheets-Sheet 4 United States Patent "ice LOAD-HANDLING TRUCK Antony S. Stokes, Hintlesham Hall, near Ipswich, and Tom Worsuop and John Robert McDonald, Ipswich, England, assignors to Ransomes & Rapier Limited, Ipswich, England Application February 28, 1952, Serial No. 273,994

2 Claims. (Cl. 214-513) This invention relates to vehicles suitable for lifting and handling goods in factories and elsewhere.

A well-known kind of lifting vehicle is commonly called a fork lift truck. It consists essentially of a truck equipped with a mast on which a support can be raised and lowered. This support usually consists of two forks projecting from a carriage which can slide on the mast. Commonly the mast is telescopic, comprising a stationary lower part and a movable upper part; the support sliding on the upper part under the control of a rope which passes from the support over a pulley on the upper part and thence to a stationary anchorage. Movement of the upper part thus controls the more extensive movement of the support. Often the upper part is raised and lowered by a hydraulic cylinder.

It is an object of the present invention to convert a fork lift truck into a dual purpose vehicle by the provision of a crane jib.

It is a further object to provide for raising and lowering the jib without complication of the lifting means of the truck.

According, therefore, to this invention, the crane jib is connected to the lifting means for the support. Preferably the fork lift truck has a telescopic mast and the crane jib is connected to the upper mast to be raised and lowered by it.

The vehicle may be used either in the same way as an ordinary fork lift truck or as a crane, and preferably the jib is made easily detachable and the fork arms or equivalent are detachable or movable to an inoperative position. This, however, is not essential, and naturally the support may be made easily detachable while the jib is in substance a permanent part of the vehicle or vice versa. In any case for many small loads it is possible to use the support to carry a load while the jib is in operative position, or vice versa, and evento use both jib and support simultaneously to carry a single load or separate loads.

Preferably the crane jib is in the form of a beam which is pivoted near its centre to the top of the upper mast with one end projecting forwards beyond the body of the truck, and the other end above the body of the truck and connected to it by a pivoted link. A fork lift truck with such a jib is shown by way of example in the accompanying drawings. These drawings will now be described in detail and further objects and advantages of this invention will appear from their description. In these drawings:

Figure 1 is a side elevation of the truck with the jib lowered;

Figure 2 is a plan;

Figure 3 is a front elevation with the jib removed; and

Figure 4 is a diagram illustrating the range of movement of the jib.

The truck has a body 2 carried by two pairs of front wheels 4 by which it is propelled and a pair of rear wheels 6 by which it is steered. The body houses an internal combustion engine which serves both to propel the truck and to provide hydraulic power. The controls for the truck are grouped in a cab 8.

A lower mast, comprising two vertical channel members 10 braced together at top and bottom, is pivoted to the body at 12. This lower mast can be inclined slightly forwards and backwards from the upright position by a hydraulic cylinder 14 which serves to rock a 2,704,615 Patented Mar. 22, 1955 shaft 16 carrying cranks 18 connected by pivoted links 20 to the channel members 10. upper mast, comprising two channel members 22 within the channel members 10, can slide vertically relatively to the lower mast, being guided by

rollers

24 and 26 carried by the channel members 22 and engaging the flanges and webs of the channel members 10. The upper mast is raised and lowered by a hydraulic cylinder 28 which operates between a bottom cross-bar between the channel members 10 and a top cross-bar between the channel members 22.

A carriage 30 can run up and down the front face of the channel members 22, being guided by rollers 32 which are carried on flanges projecting rearwards from the carriage and which engage the flanges of the channel members 22. Two fork arms 34 are pivoted to the carriage at 36. When a load is to be lifted by them they are swung downwards from the position shown into the position 38. The carriage 30, and with it the fork arms 34, is raised and lowered by a rope 40 which runs from an anchorage 42 on the carriage 30, over a pulley 44 at the top of the upper mast, round an equalizer 46 at the top of the lower mast, round a second pulley 48 at the top of the upper mast, and thence to a second anchorage 50 on the carriage 30. By this means vertical movement of the upper mast imparts a vertical movement of twice the extent to the carriage. That is to say when the upper mast is fully raised the carriage has reached the top of the upper mast while when, as shown in Figure 1, the upper mast is fully lowered, then the carriage is at the bottom of the upper mast and the fork arms when in operative position rest on the ground.

The components thus far described are those of one ordinary type of fork lift truck.

On the top of the upper mast are two half bearings 52 in which rest pivot pins 54 on a jib 56. These pivot pins 54 are carried by webs 58 on the underside of the jib near its centre. A wishbone-shaped tie 60 is pivoted at 62 to the rear end of the jib and is pivoted on pins 64 to the body 2. When the upper mast is raised and lowered the jib 56 rises and falls between the positions 66 and 68 shown in Figure 4. The jib is slightly cranked at its centre, so that the part of the jib between the pivot 54 and the forward end 70 moves between positions substantially equally inclined above and below the horizontal, while the part of the jib between the pivot 54 and the rear end is substantially horizontal when the jib is in the position 66 and is considerably inclined when the jib is in the position 68. In this way the end 70 is caused to move in an arc which departs very little from the vertical, while at the'same time the overall height of the vehicle when the jib is lowered is kept to a minimum.

A hook 72 is fitted to the end 70 of the jib and can be used for lifting loads. For most purposes, however, a further hook 74' is provided on a rope 76 which, according to the load to be carried, is rove over one of three pulleys 78 on the jib. Thence the rope passes over a pulley 80 above the pivot 54, and is anchored to a drum 82 mounted on a cross-bar between the channel members 10 of the lower mast. The drum 82 can be turned by a handle 84 to vary the available length of rope 76 and the rope is normally prevented from unwinding by a pawl 86. When the upper mast is raised carrying the jib with it, a length of rope 76 equivalent to the travel of the upper mast is drawn over the

pul leys

78 and 80. Thus, as shown in Figure 4, the travel of the hook 74 is greater than that of the end 70 of the jib. This has not only the advantage of reducing the necessary travel of the jib so that the movement of its end may be more nearly vertical but, in addition, when the hook is lowered the free length of rope 76 makes it unnecessary for the jib to be manoeuvred accurately over a position from which a load is to be lifted or in which it is to be set down. Turning of the drum 82 varies the range of movement of the hook 74 without altering its extent. In addition the drum 82 can be used to take up the surplus when the rope 76 is rove over one of the inner pulleys 78. The drum 82 is not of course turned when there is a load on the hook 74.

When the hook 74 is required to be close up to the jib throughout the vertical movement of the jib, the rope 76 may be disconnected from the drum 82 and instead led

round guides

88 and 90 and anchored to hooks 92 on the upper face of the jib. This is done either when a tall load is to be lifted in restricted headroom, or when a load is to be lifted on the forks and the hook 74 is required to be out of the way.

The jib and tie 60 can be removed entirely to permit full range of movement of a load carried on the forks. This may be achieved very simply by driving the vehicle beneath an overhead hook which is shackled to a lug 94 on the jib above its point of balance. Then retaining pins 96 on the bearings 52 are withdrawn and so also are the pins 64. The tie 60 is swung up and lashed to the jib, the upper mast is lowered, and the vehicle can be driven away.

We claim:

1. A fork lift truck equipped with a crane jib comprising a body, a lower mast mounted at the front end of said body, an upper mast movable telescopically on said lower mast, a load support on said upper mast, a crane jib in the form of a beam pivoted substantially at its center on the top of said upper mast and extending longitudinally of said body, the front end of said beam being equipped with a lifting hook, the rear end of said beam lying above the rear end of said body, a substantially vertical link pivoted to the rear end of said beam and the rear end of said body, means for raising and lowering said upper mast and load support, the part of said beam forward of said upper mast moving, as said upper mast is raised, between extreme positions inclined at substantially equal angles below and above the horizontal, whereby said hook can be raised or lowered in a substantially vertical path, a pulley on said beam at the front end thereof, a second pulley on said beam adjacent the central pivot thereof, a fixed anchorage on said lower mast, a rope led from said fixed anchorage over said pulleys to a free end hanging below said front end of said beam, and load-engaging means on said free end of said rope, the movements of said upper mast being employed to raise or lower said load-engaging means.

2. A load-handling truck equipped with a crane jib and lift forks comprising, a truck body, a substantiallyvertically disposed lower mast mounted at the front end of said body, an upper mast movable telescopically on said lower mast, a carriage, provided with lift forks, and mounted to travel along said upper mast for substantially the entire length of said upper mast; means for moving said carriage along said upper mast, actuated by the movement of said upper mast with respect to said lower mast; a crane jib in the form of a beam pivoted substantially at its center on the top of said upper mast, and extending longitudinally of the truck body, the rear end of said beam lying above the rear end of said body; a substantially vertical link pivoted to the rear end of said beam and the rear end of said body, the front end of said beam being equipped with a lifting hook; means for raising and lowering said upper mast whereby, as said upper mast is raised from a lowered position, said hook is raised in a substantially vertical path, and said carriage is simultaneously caused to move upwardly along said upper mast.

References Cited in the file of this patent UNITED STATES PATENTS 1,895,939 Presbrey Jan. 31, 1933 2,050,821 Vercoe Aug. 11, 1936 2,347,822 Goldup May 2, 1944 2,372,220 Mork Mar. 27, 1945 2,445,614 Flynn et al. July 20, 1948 2,471,364 Weber May 24, 1949 2,493,750 Bucksath Jan. 10, 1950 2,494,651 Flynn Jan. 17, 1950 2,506,242 Shoemaker May 2, 1950 2,605,002 Graves July 29, 1952