GB2039837A - Steering Transmission for Self Propelled Vehicle - Google Patents

Abstract

A steering transmission assembly in a self-propelled floor conveying vehicle with rear-wheel steering wherein two chain drives 17, 19, one downstream of the other, transmit a steering movement of the steering wheel to the steered rear wheel, two sprocket wheels 10, 12 journalled on an intermediate shaft 13 each respectively engaging one chain drive and the second chain drive being arranged for multiplication of the steering moment. The sprocket wheel 10 engages the outside of the chain 11 of the first drive 17 so that the rear wheel 4 turns in the opposite direction to steering wheel 5. The drive 17 is disposed in a channel 18 readily accessible from one side of the vehicle. <IMAGE>

Description

SPECIFICATION Steering Transmission and Multiplication Assembly for Self Propelled Vehicles The invention relates to a steering transmission and multiplication assembly in self-propelled floor conveying vehicles steerable by their stern, particularly lifters having at least one steerable stern wheel mounted on a pivoted bogie, in employing chain drives and an intermediate shaft arranged at the stern of the equipment and having two sprocket wheels of equal size or preferably different sizes.

In floor conveying vehicles of this type, the transmission of a steering movement applied to the steering wheel by the driver from the steering wheel and the at least one steerable stern wheel mounted on a pivoted bogie necessitates a reversal of rotation from the steering wheel to the steered stern wheel. Furthermore, the moment applied by the driver at the steering wheel should not exceed a reasonable level and should be amplified so as to ensure a steering movement of the stern wheel even under unfavorable operating conditions.

For meeting these requirements in employing mechanical transmission members there is known for example: The steering shaft connected to the steering wheel engages an one-stage gear drive which effects reversal of rotation and with a corresponding selection of transmission ratio also contributes to amplify the steering moment. The further connection of steering gear to stern wheel will then be effected via one or several drag chains. Due to the amplification of the steering moment which is effected already in the region of the steering shaft the downstream connected chain drives must be of a correspondingly sturdy design. With the commotation caused when driving there will result, in an increased degree, oscillations, and this quite apart from the fact that the heavy duty chain drives will also entrain considerable design requirements with respect to guiding means.Since due to space requirements the positions of the sprocket wheels mostly do not permit to extend the chains exactly or respectively approximately along one and the same level, there is arranged, in the stern of the machine, an intermediate shaft which mounts two sprocket wheels of different sizes compensating level differences and providing the remainder of the required steering moment amplification.

A drawback of the described design is the complexity of the mechanical elements required, particularly in including a steering gear box.

Service requirements are likewise high. If there is employed additionally hydraulic servo steering means, the pump of such servo system is in most cases arranged in the stern, and the booster system is arranged in the steering column. The resulting power flux is then of a rather complicated lay-out and increases the costs.

It is the object of the present invention to provide, in floor conveying vehicles of the above type, a simple steering transmission and multiplication assembly consisting of chain drives which assembly will be subject to loads in a favorable manner, will moreover be readily accessible for service and will allow an economical and favorable design of the chain drives.

In accordance with the present invention, this object is achieved by the fact that there are provided two chain drives, one of these chain drives being passed about a chain pinion at a steering wheel and driven thereby and engaging a sprocket wheel of the intermediate shaft in a manner to effect reversal of rotation, and that a transmission ratio is provided in the region of the -intermediate shaft and the second chain drive between the intermediate shaft and a sprocket ring or respectively a chain guide on the pivoted bogie.

This assembly achieves a simple design in the region of the steering wheel and up to the stern of the vehicle whereby the transmission members leading to the stern of the vehicle may be in light construction, and furthermore assembly and service are facilitated by the concentration of the steering moment amplification to the stern of the vehicle. The design of the first chain drive is also simplified since this chain drive may be designed in a relatively light construction.

With special advantage a stern-mounted chain pinion of the first chain drive may be associated with a sprocket wheel on the intermediate shaft in a manner so that the chain of the first chain drive engages the sprocket wheel at one side along an arcuate engagement region. By this expedient, the first chain drive becomes a self-contained unit which facilitates assembly and service. Suitably, the first chain drive of a light construction will be accommodated within an externally accessible channel whereby the stern-mounted chain pinion is adapted to be dismounted toward the outside and toward the side of the floor conveying vehicle, in simultaneously releasing the chain engagement with the sprocket wheel on the intermediate shaft.

This type of assembly of the stern-mounted chain pinion also provides for a favorable tensioning in this region, in ensuring a sufficiently large angle of engagement since the first chain drive being a self-contained chain guide engages by an outer side the associated sprocket wheel on the intermediate shaft.

It is preferred that the transmission ratio is provided substantially in the second, short chain drive in the stern of the vehicle between the pivoted bogie and the associated sprocket wheel on the intermediate shaft. This arrangement allows favorable transmission ratios.

In a preferred further embodiment the intermediate shaft may be divided or respectively the sprocket wheels may be individually journalled on the intermediate shaft, with the interposition of a torque amplifier. Torque amplifiers of this type are conventional and available.

Special advantages reside in the fact that the usage of a relatively expensive steering gear box may be dispensed with and that essential members of the steering assembly may be designed in a relatively light construction.

Furthermore, this design allows the spatially favorable arrangement of additional steering moment assisting means.

According to another advantageous design in a floor conveying vehicle in which the steerable stern wheel is concurrently the drive wheel, the sprocket ring or respectively the chain guide of the second chain drive at the steerable stern wheel may be an integral housing component of a steerable wheel propulsive unit mounted in the form of a pivoted bogie.

In the following, the invention will be described with reference to an embodiment illustrated schematically in the appended drawing.

The drawing illustrates the top view of a threewheel floor conveying vehicle 1 with front wheels 2, 3 on rigid axes as well as a stern wheel steerably mounted on a pivoted bogie.

Hereby is contemplated that either the front wheels 2, 3 or the stern wheel 4, optionaliy also all wheels, may be driven. The propulsive means are not shown since embodiments thereof are known.

The manual steering wheel 5 arranged in the front is associated with an operator's seat and is connected to a chain pinion 6 by a central steering column; the chain pinion drives a first chain drive 1 7. The chain 11 thereof is being passed about the chain pinion 6 and extends to another chain pinion 9 arranged in the stern of the vehicle via deflector rollers 7, 8 the number of which is dependent upon the actual lay-out.

Thereby becomes apparent the advantageous design in that the first chain drive is arranged within a channel 18 which particularly is accessible from the outside and at one side of the chassis of the floor conveying vehicle. Within this channel may also be arranged the chain pinion 9 in its bearing so as to be mountable and dismountable from the side of the vehicle. This chain pinion is arranged in the vicinity of an intermediate shaft 13 with two sprocket wheels 10 and 12, that is behind this intermediate shaft and in a position so that the chain 11 is not being passed about the associated sprocket wheel 10 but is being kept in engagement at the outside along a sufficient arcuate region.This effects not only a reversal of rotation or respectively of the sense of rotation from steering wheel 5 to intermediate shaft 1 3 but concurrently facilitates mounting and dismounting.

On the intermediate shaft 1 3 is furthermore arranged the sprocket wheel 12 which is preferably of a smaller diameter than the sprocket wheel 10. This sprocket wheel 12 actuates the chain 14 of the second chain drive 1 9 which transmits, by its chain, the steering movement to a sprocket ring or respectively a chain guide 1 6 on the pivoted bogie 1 5 and thereby onto the steered wheel 4 which is mounted on the bogie.

As will become apparent, the torque amplification is concentrated in the stern of the vehicle so that the chain drive 17 may be of a light construction and be arranged so as to be easily accessible.

Claims (7)

Claims

1. A steering transmission and multiplication assembly in self-propelled floor conveying vehicles steerable by their stern, particularly lifters having at least one steerable stern wheel mounted on a pivoted bogie, in employing chain drives and an intermediate shaft arranged at the stern of the equipment and having two sprocket wheels of equal size or preferably different sizes, said assembly characterized in that there are provided two chain drives, one of said chain drives being passed about a chain pinion at a steering wheel and driven thereby and engaging a sprocket wheel of said intermediate shaft in a manner to effect reversal of rotation, and that a transmission ratio is provided in the region of said intermediate shaft and said second chain drive between said intermediate shaft and a sprocket ring or respectively a chain guide on said pivoted bogie.

2. A steering transmission and multiplication assembly according to Claim 1, characterized in that a stern-mounted chain pinion of said first chain drive is associated with a sprocket wheel on said intermediate shaft in a manner so that the chain of said first chain drive engages said sprocket wheel at one side along an arcuate engagement region.

3. A steering transmission and multiplication assembly according to Claim 2, characterized in that said first chain drive is in light construction and is disposed at one side of said floor conveying vehicle wholly or partly within a channel accessible from the outside whereby said sternmounted chain pinion is adapted to be dismounted toward the outside and toward the side of said floor conveying vehicle, in simultaneously releasing the chain engagement with said sprocket wheel on said intermediate shaft.

4. A steering transmission and multiplication assembly according to any of the preceding Claims 1 to 3, characterized in that said transmission ratio is provided substantially in said second, short chain drive in the stern of the vehicle between the pivoted bogie and the associated sprocket wheel on said intermediate shaft, said sprocket wheel being preferably smaller than the sprocket wheel associated with said first chain drive.

5. A steering transmission and multiplication assembly according to any of the preceding Claims 1 to 4, characterized in that said sprocket wheels on said intermediate shaft are journalled individually, with the interposition of a torque amplifier.

6. A steering transmission and multiplication assembly according to any of the preceding Claims 1 to 5, characterized in that said sprocket ring or respectively said chain guide of said second chain drive at the steerable stern wheel is an integral housing component of a steerable wheel propulsive unit mounted in the form of a pivoted bogie.

7. A steering transmission and multiplication system substantially as herein described with reference to the accompanying drawing.