Conveyors: power-driven – Conveyor section – Live roll
Patent
1996-08-19
1998-03-31
Bidwell, James R.
Conveyors: power-driven
Conveyor section
Live roll
B65G 1306
Patent
active
057328137
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a motorised head pulley with a rotating drum, which is driven by a hydraulic motor permanently mounted in the pulley.
Motorised head pulleys of the type mentioned in the introduction are known from U.S. Pat. Nos. 3,788,605 and 4,148,464, where the hydraulic motor is arranged to be driven by means of a standard oil-based hydraulic medium. It has proved, however, that it is difficult to arrange these motorised head pulleys with such a high degree of tightness that the oil-based hydraulic medium cannot possibly escape to the surroundings and pollute them. The application of these motorised head pulleys for driving for example conveyors in food processing factories such as slaughterhouses in particular, is today very restricted as a consequence of the risk mentioned that the oil-based hydraulic medium escapes to the surroundings and pollute for example foodstuff when leaks occur in the pulley or in pressure pipes.
It should also be mentioned that in addition to this last mentioned motorised head pulley, motorised head pulleys are known where the driving motor is an electro-motor, see for example U.S. Pat. No. 5,088,596. On the background of the drawbacks mentioned above, these motorised head pulleys have been used increasingly for driving conveyors especially in food processing industries, but still they involve a not inconsiderable risk of leaks at the oil lubricated transmission, which may also lead to unwanted contamination of the surroundings. The electrically driven head pulleys often have a high, unwanted generation of heat, when they have received an often pre-determined number of start/stop signals within a given period of time, and the high degree of heat generation heats in an unwanted manner the driven arrangement such as a conveyor. The high degree of heat generation causes different friction and uneven pull of the conveyor, which will quite often lead to increased wear or break-down.
SUMMARY OF THE INVENTION
The motorised head pulley according to the present invention is characterised in that a reduction gear is inserted between the motor and the pulley, and that the motor and the reduction gear comprise moving parts which are arranged for operation in contact with a water-based, lubricant-free pressure fluid.
A motorised head pulley is hereby provided, which can be used for many, different purposes, without the necessity of paying attention to a risk of pollution from the hydraulic medium, especially during operation, but also during installation and service of the motorised head pulley. The high conductivity of the water-based pressure medium will ensure a necessary and very efficient transport of the frictional heat away from the moving parts of the reduction gear.
According to the invention, the wear of the sliding surfaces is reduced at operation in water.
The invention has proven to provide a particularly functional and reliable reduction gear in connection with a hydraulic motorised head pulley.
The motorised head pulley can suitably be suspended by the shaft, for example by means of a fork-like unit gripping each shaft end, and the motorised head pulley can suitably be installed direct for replacing existing motorised head pulleys, driving for example conveyors.
The invention provides particularly efficient cooling of the reduction gear and the moving parts of the hydraulic motor, and thereby heat removal via the passing pressure fluid.
A particularly efficient heat removal from the pulley via the passing pressure fluid is ensured.
According to the present invention the plastic material can in a particularly suitable manner be polyetherether ketone reinforced with carbon fibres. However, many other types of thermoplastic materials may be used, as for example polyamide.
According to the present invention the thermoplastic material may have a content of fillers, such as glass, graphite, polytetrafluoroethylene or carbon, and especially in a fibre form.
According to the present invention the motorised head pulley can be used wit
REFERENCES:
patent: 1820985 (1931-09-01), McKee
patent: 4013166 (1977-03-01), Weady et al.
patent: 5088596 (1992-02-01), Agnoff
Andersen René Schibsbye
Nielsen Jens J.o slashed.rgen
Bidwell James R.
Danfoss A/S
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