Source: {"pile_set_name": "USPTO Backgrounds"}

Unbalance type exciter serve for generating exciting forces changing over time, by means of which components coupled to the exciter can be caused to vibrate. They are employed in many technical fields, e.g. in vibrating conveyors, in vibrating screens, in compacting devices like e.g. vibratory plates or vibratory rollers, in vibratory pile driving devices and in vibration excited drilling and cutting devices.
For generating the exciting forces, depending on the design concept, one or more shafts, at which unbalance weights are arranged, are put into rotation.
In vibratory rollers it is preferred to arrange the unbalance type exciter within the roller drum and to decouple the rest of the machine with respect to vibrations in order to keep the vibrating masses and therewith the energy requirement as low as possible.
However, especially in case of relative narrow soil compacting devices like trench rollers, there is the problem that the unbalance type exciters known today, when providing a suitable exciting power comprise an overall length which makes it difficult or even impossible to arrange them axial in line with the roller drive in the rotational centre of the roller, what is desirable since in that case the starting point of the exciting forces substantially coincides with the centre of mass of the roller arrangement formed in this way so that an optimal vibration behaviour of the rollers can be achieved and the remaining structure of the machine is exposed only to minor additional load due to the exciting forces.
Hence, it is an object of the invention to provide an unbalance type exciter for soil compaction devices which has a substantially reduced overall length compared to known unbalance type exciters.
This object is achieved by the present invention.