Electricity: transmission to vehicles – Flexible extensions – Reels
Patent
1987-11-20
1989-08-08
Cherry, Johnny D.
Electricity: transmission to vehicles
Flexible extensions
Reels
H02G 1102
Patent
active
048555398
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a stowing device for a cable feed, particularly for the connecting cable of a central aircraft power supply system at airports. The device has a cable fixed point at or close to a passenger gate and has a double cable drum which receives, without twisting, corresponding lengths of cable as service cable and equalization cable. The drum comprises a service drum for the service cable and an equalization drum coaxial therewith for the equalization cable, as well as a drive for both directions of rotation of the drum.
In one known stowing device of this type (German Pat. No. 33 04 276) there is a double cable drum the equalization cable of which is arranged between a fixed cable connection and the radially inner end of the service cable and is radially displaceable in the form of an opening and closing spiral upon the winding and unwinding respectively of the service drum. This means that the length of cable which forms the equalization cable represents an unusable length of cable and to this extent therefore the cost of the stowing device is considerably increased. Such connecting cables are expensive parts. In one embodiment, which is common at the present time, its outside diameter is 46 mm; the cable cross section consists of four cable wires for the 400 cycle three-phase current supply and, in addition to this, of 20 to 30 control lines. The unusable length of the equalization cable in one practical embodiment of the known stowing device amounts to about two-thirds of the length of the service cable, i.e. about 12 meters for a prescribed length of the service cable of 18 meters.
Thus the object of the present invention is to create a stowage device of the aforementioned type which uses, as a whole, a shorter connecting cable than the known device does.
In order to achieve this purpose, it is proposed, in accordance with the invention, that a movement of translation be superimposed upon the rotation of the double cable drum, the double cable drum being displaced in a longitudinal guide over a distance which is equal to the length of equalization cable which is freed or wound up while the line cable is being unwound or wound up respectively.
With this solution, the path of travel of the double cable drum has a length which corresponds appoximately to the length of the equalization cable, and this is added to the length of the service cable. The maximum usable length of the stowage device thus corresponds to the sum of the unwound lengths of equalization cable and service cable with the equalization cable being completely unwound. Expressed mathematically, with n turns, an average diameter of the service drum D and an average diameter of the equalization drum d, the usable length L corresponds approximately to the formula:
As compared with the known stowing device described at the beginning hereof, there is obtained a saving in total cable length equal to the unwound length of equalization cable. If the place of attachment of the double cable drum is on the floor of the gate, for instance at the outermost end of the head of the bridge of a passenger gate, guidance of the double cable drum can be developed so that it can be extended beyond the head of the gate. In this way, there is even obtained a saving of length of service cable, since the extension path can be subtracted from the maximum length of the service cable.
By the proposal in accordance with the invention, it is possible to minimize the unusable length of the connecting cable to the approximately S-shaped piece of connecting cable between the equalization drum and the service drum which is held fixed in space with respect to the double cable drum. Stretched out, this connecting piece corresponds to not more than approximately the diameter of the service drum.
One essential embodiment contemplates having the service cable and the equalization cable wound up spirally in the same direction on their corresponding drums.
By spiral winding in the same direction it is to be understood that, starting from the inner turn,
REFERENCES:
patent: 944786 (1909-12-01), Hinds
patent: 1868409 (1932-07-01), Crispen
patent: 2518072 (1950-08-01), Rushworth
Cherry Johnny D.
Pape Joseph D.
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