US1722125A - Lifting machine such as a crane - Google Patents

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m 23, 1929. BERNHARD 1,722,125

LIFTING MACHINE SUCH AS CRANES Filed April 25, 1928 Patented July 23, 1929.

snares g v 1,222,125 rarest rare.

JOI-IANN MARTIN BERNHARD, OF MAISING, NEAR MUNICH, GERMANY, ASSIGNOR TO A T G ALLGEMEINE TRANSPORTANLAGEN-GESELLSCHAFT li'I. E. ii, 0E LEIPZIG, GERMANY, A CORPORATION OF GER-MANY.

LIFTING MACHINE SUCH .AS A CRANE.

1 Application, filed April 23, 1928, Serial No.

Winch gears or winch gears which were hori- I V zontally displaceable on the crane framework have hitherto been employed, which winch gears had to be designed and dimensioned for the whole load to be raised and consequently also necessitated the use of powerful driving motors. lVinches of this kind are equipped with driving gear, brakes, couplings, drums and controlling devices, which likewise have to be constructed to correspond to the full load which the motor has to carry. As consequence of these facts, the said known machines must of necessity have alarge total weight and consequently are very expensive in initial cost. If, now, the raising gear or the loading plant respectively is to be provided with conveying means, such as, for instance, grabs, tipping vessels, grippers or the like, then expensive closing and emptying devi es are necessary in addition, which renders the construction of the whole winch gear considerably heavier. More-over, the attendance of winch gear of this kind necessitates the most careful attention on the part of the crane driver, especially in the case of winch gear having only one motor, in which the carrying out of the control operations in the wrong order may cause the falling down of the conveying means.

The idea of partly counter-balancing the load suspended from the crane by means of movably arranged counterweights is not new per sefor instance, in the construction of lifts it is universally customary to counter balance the weight of the cage and half the maximum working load. Nevertheless, in such cases, the upward and downward movements of the cage, and likewise the contrary movements of the counter-weight are produced by means of a stationary winch gear.

According to the present invention the raising and lowering of the load is efiected by means of a climbing crab adapted to move up and down in the framework of the lifting machine and provided with a driving motor for effecting the said movements, which crab can also be employed as a partial counter- 272, 2 01, and in Germany March 23, 192?.

weight for the load. The said motor drives chmbing pinions through intermediary gear ing, which pinlons engage with rack bars or the like arranged on the framework of the lifting machine.

With a lifting machine of this kind, the load which is to be moved is partly counterbalanced by the total weight of the motor driven climbing crab, so that the total lifting work done on theload is in part effected by means of the descending crab, and only the remaining amount has to be done by the driving motor. As compared with lifting machines with stationary winches, the necessary motor output is very considerably diminished by the employment of a climbing crab.

The weight of the climbing crab is made up of the individual weights of the crab framework, the driving motor together with the gearing and possibly couplings and a winch drum which is necessary in particular cases.

The individual weight of such a climbing crab may be artificially increased or diminished by the provision of additional weights or counterweights.

A preferred constructional form of a crane according to the invention is illustrated diagrammatically by way of example in the accompanying drawings, in which Fig. 1 is a side elevation of the crane.

Fig. 2 is a plan of the lower part of the crane pillar,

Fig. 3is a detail showing the crab in front elevation,

Fig. 4 is a plan of Fig. 3, and

Fig. 5 is a side view of the crab and the supporting structure.

As can be seen from the drawings, theclimbing crab moves up and down in the framework pl of the crane, supported by a pillar having three legs (Z. The said crab consists of a rigid frame in which the mechanical parts such as the motor h, the rack pinions 7" and the gear 2' together with the brakes a, m are arranged. The rack pinions f engage with rack bars g, which are fixed in any suitable manner to the framework cl of the crane or the like. The load such as the grab c is suspended from ropes or cables at, which pass over snatch blocks b and are connected to a drum is on the crab, which is driven by the motor it through gears 2' and Z.

The weight of the climbing crab may be artificially increased by means of an additional weight 0.

The mode of operation of a plant of this kind provided with a climbing crab is as follows:

The raising and lowering of the load is effected by downward and upward movement of the climbing crab respectively, the said crab being set in motion by means of the motor h. If it is desired to raise or lower the grab by the means of drum 7a, the crab is held stationary by the brake a, and the drum is driven by the motor it, through gears 2' and Z.

It now the grab is to be raised or lowered with the crab acting as a counterweight, the motor 70 is switched back from the driving gear of the drum on to the driving gear of the rack pinion f and the brake m is put into operation for the purpose of maintaining the drum is stationary. By releasing the brake n at the same time the rack pinion f will then be driven by the motor h, and the crab will move upwards or downwards respectively.

If the loading place is not at the same height as the unloading place, it'is preferable to'provide an indicating device showing the position of the crab at any given time, so that the crane driver is informed as to the position of the crab and oi the goods to be conveyed.

I claim: J

1. In a lifting machine, such as a crane, for

' the raising and lowering of loads, the combination of a framework, a grab, a climbing crab adapted to move up and down in said framework and to act as a partial counterweight for the load to be raised, a winch arranged onrsaid crab adapted to move said grab up and down, driving means on said crab adapted to move said crab up and down and to operate the winch, a brake on the crab adapted to hold the winch when the crab is raised or lowered, and a second brake on the crab arranged to restrain movement of the:

crab when the winch is operated.

2. In a lifting machine, such as a crane, for the raising and lowering of loads, the combination of a framework, a grab, a climbing crab adapted to move up and down in said frame work and'to act as a partial counterweight for the load to be raised, a winch arranged on said crab adapted to move said grab up and down, driving means on said crab, coupling means on the crab adapted to couple said driving means so as to move said crab up and down, couplin means on the crab'adapted to couple said driving means with said winch, a brake on the crab adapted to hold the Winch when the crab is raised or lowered, and a second brake on the crab arranged to restrain movement of the crab when the Winch is operated.

Signed at Munich, Germany, this 2nd day of April, 1928.

J OH. MARTIN BERNI-IARD.

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