Conveyors: power-driven – Conveying system having plural power-driven conveying sections – With means for altering the speed of a section
Reexamination Certificate
1998-12-11
2002-10-29
Hess, Douglas (Department: 2167)
Conveyors: power-driven
Conveying system having plural power-driven conveying sections
With means for altering the speed of a section
Reexamination Certificate
active
06471039
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a conveyor system having a plurality of conveyor sections arranged in series for transporting articles and a method for operating same. The articles may be accelerated on the conveyor system but adjacent conveyor sections have substantially the same speed when the articles are passed between them so as to reduce wear or damage to the articles. In particular, the invention relates to a conveyor system for use, e.g., at airports for conveying luggage.
BACKGROUND ART
A high speed conveyor system for transportation of luggage between a main airport terminal and a number of aircraft concourse areas is described in U.S. Pat. No. 5,056,647. The luggage is accelerated stepwise from a handling speed of, e.g., 0.5 m/s to a conveying speed of, e.g., 7.6 m/s via a number of acceleration sections, e.g., six, situated in series, where a following section runs with a higher, constant speed than the preceding section. The luggage is transported over a long distance at the high conveying speed and is decelerated stepwise to a handling speed, the deceleration being performed in a similar manner as acceleration, i.e. via a number of deceleration sections. A surveillance system is placed in each section so as to monitor whether a section is being overloaded with luggage, in which case the section is stopped for manual correction.
Another system for transporting luggage in, e.g., airports is described in U.S. Pat. No. 4,227,607. This system comprises a number of consecutive belt conveyor sections capable of running independently and placed between check-in stations and a luggage sorting station. Each section has a photo sensor arranged at the upstream end of the section for detecting pieces of luggage. The conveyor section receives information for the following section regarding whether it is running and receives information from the preceding section regarding whether it has luggage placed on its downstream end. Under normal conditions of use, all sections are running without interruptions. When an end station is blocked by luggage, all sections are stopped, and will under these conditions only be restarted in order to fill up upstream sections with luggage, so as to accumulate luggage.
U.S. Pat. No. 5,150,781 discloses a conveyor module with individual PLC unit and sensors for detecting conveyed objects. The modules may be assembled in a number of ways so as to build up a conveyor system, wherein each control unit of each module is capable of communicating with control units of adjacent modules. The modules are in particular suited for building up a conveyor system for assembly lines. An object of the invention according to U.S. Pat. No. 5,150,780 is to provide a conveyor system, wherein the position of the modules can be switched without requiring a reprogramming of the control units and installation of new cabling between a central control unit and each conveyor module.
U.S. Pat. No. 5,285,887 discloses a conveyor system comprising a number of individual zones, wherein articles can be transported by means of chains, belts, cylinders etc. Each zone is controlled individually and may communicate with the preceding zone and the following zone. The system further comprises sensors for detecting articles on the conveyor system. The system is capable of running both in a forward direction and in a backward direction. Under normal conditions of use, the driving unit of a zone is inactive until an article is present in the preceding zone which passes a control signal to the present zone for activating the driving unit of the present zone. The present zone receives the article and passes it further on to the following zone if a control signal is received from the following zone regarding that it is ready for receiving an article. In case the following zone is not ready for receiving an object, the driving means of the present zone is stopped until the following zone is ready to receive the article. In this way, the conveyor system obtains an ability of accumulating articles.
DESCRIPTION OF THE INVENTION
It has, however, been found that the prior art systems have certain disadvantages, in particular in relation to applications wherein articles are to be accelerated and/or decelerated, and/or in relation to applications wherein articles are to be conveyed over relatively long distances at relatively high conveying speeds, e.g., between airport terminals.
Thus, accelerating and decelerating section of prior art systems may cause wear and/or damage to conveyed articles when passing articles between conveyor sections having different conveying speeds due to slip between the article and the conveyor section. Moreover, at least some of the prior art systems may cause considerable obstructions to the flow of articles in case one or more conveyor sections stop(s) running due to unforeseen events. In particular for applications wherein a number of articles is conveyed over a relatively long distance and wherein a large number of articles is being conveyed along the conveyor system at a time, a temporary stop of a conveyor section may cause a large number of articles to arrive at their destination with a delay. This may cause further delays, e.g., flight departure delays in case the conveyor system is applied for conveying luggage at an airport.
Furthermore, some prior art systems, in particular those comprising relatively long conveyor sections have a tendency of generating a considerable noise level which may be unpleasant to people and in some cases even be hazardous to human ears. The noise may be generated, inter alia, by unsteady oscillations of relatively long and heavy conveyor belts and/or by associated driving units, such as electromotors. As a further disadvantage, such systems have a relatively high energy consumption.
Therefore, an object of the present invention is to provide a conveyor system which is capable of conveying articles both over relatively long distances and over relatively short distances at different conveying speeds while causing a minimum of wear to the conveyed articles when passing from one conveyor section to another. A further object of the present invention is to provide a conveyor system which is flexible in the sense that a unforeseen stop of a single or a few conveyor sections will not instantaneously cause other conveyor sections to stop. A still further object of the invention is to provide a conveyor system which has a relatively low energy-consumption while generating a relatively low noise level.
It is a further object of the invention to provide a conveyor system comprising conveyor sections on which the articles may be conveyed at a low handling speed at a loading station, a discharging station, in curves etc., while being conveyed at a high speed at other locations along the conveyor, and wherein this can be obtained without subjecting the articles to stress when passing from one conveyor section to the other.
A still further object of the invention is to provide a method of operating such a conveyor system.
Thus, the present invention provides a method of operating a conveyor system comprising at least two conveyor sections arranged in series, said method comprising
successively loading articles onto the conveyor system,
selectively driving the respective conveyor sections at varying speed so as to move the articles thereon in a direction of transportation along the conveyor system,
detecting the position of an article on the conveyor system by means of detecting means arranged at one or more locations along the length of said system,
generating a detecting signal when an article has been detected by the detecting means,
determining, from a speed associated with said article, a desired downstream speed of said article at the downstream end of a first of said conveyor sections,
controlling the varying speed of said first conveyor section when said article is conveyed thereby, in response to the detection signal, so as to obtain the previously determined downstream speed of said article when approaching a downstream en
Bruun Brian
Kibsgaard Steen
Crisplant a/s
Hess Douglas
LandOfFree
Conveyor system and a method for operating same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Conveyor system and a method for operating same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Conveyor system and a method for operating same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2985562