Conveyors: power-driven – Conveyor system for moving a specific load as a separate unit – System includes a load supported by a conveyor portion which...
Reexamination Certificate
2001-11-06
2003-11-18
Bidwell, James R. (Department: 3651)
Conveyors: power-driven
Conveyor system for moving a specific load as a separate unit
System includes a load supported by a conveyor portion which...
C198S349000, C198S370030
Reexamination Certificate
active
06648126
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a transport system including at least one product carrier which is adapted to be moved along a slide way by means of a linear motor drive unit comprising a primary part and a secondary part.
Such a transport system is known from DE 4413625A1. In the case of this known transport system a carriage means, used as a product carrier, is moved along a first slide way by means of a linear motor drive unit and is displaceable together with said first slide way along a second slide way. The first slide way has arranged thereon a stator or primary part of the linear motor drive unit. A complementary rotor or secondary part is secured to the carriage means. The carriage means supports a vertically displaceable support column, a product or workpiece carrier in the form of a gripper being arranged at the at the lower end of said support column.
The known transport system serves to take hold of and lay down a specific product or workpiece by means of the gripper. The carriage means is movable to a limited extent along the first slide way between two fixed points, and the carriage means, together with said first slide way, is movable as a whole along the second slide way between two further points so that the articles held by the gripper can, on the whole, be moved along each of the three coordinate axes along three-dimensional path curves.
The known transport system is disadvantageous insofar as only special articles, goods, workpieces or products can be transported due to the gripper and insofar as only one product carrier can be moved by external influence via the primary part of the linear motor drive unit.
It is therefore the object of the subject matter of the application to improve the transport system described at the start in such a way that basically any number of product carriers can be moved along the slide way independently of one another and can be used in a versatile manner for transporting a great variety of products or workpieces.
In connection with the features of the generic clause of claim
1
, this object is achieved in that the product carrier is provided with a substantially flat base plate for transporting objects, the base plate having associated therewith the primary part and the slide way having associated therewith the secondary part.
A transport system having a similar structural design is described in DE 298 16 285 of the same applicant; in this transport system, the secondary part is arranged on the product carrier and the primary part is arranged on the slide way.
In comparison with the last-mentioned prior art and, similarly, also in comparison with the first-mentioned prior art, the present invention is so conceived that the linear motor is used in the reverse mode so that each product carrier can be controlled individually and independently of other product carriers. Each product carrier can therefore be accelerated or delayed separately so that buffering of the individual product carriers can be dispensed with e.g. along path lengths where a congestion of product carriers may occur. An individual and conflict-free control of the various product carriers is obtained, and it will not be necessary to provide stoppers and/or shock absorbers on the product carriers. In addition, a smaller number of product carriers is required, since only as many product carriers are required as there are work orders to be executed along the slide way and the work stations located at said slide way. In comparison with the transport system according to DE 298 16 285, it can be assumed that the number of product carriers required for a production process can be reduced by 50%.
Due to the separate control of the individual product carriers, said product carriers can be accelerated and delayed more effectively, whereby the feed/discharge cycle times will be reduced and production downtimes can be made up for by variable speeds of the product carriers.
In view of the individual control of each product carrier, said product carriers are protected against running into the back of other product carriers, i.e. they are protected against colliding with other product carriers, so that squeezing and shearing points on the product carrier will be avoided. Such squeezing and shearing points may otherwise occur when two successive product carriers collide or when a product carrier gets stuck in its slide way and when e.g. a subsequent product carrier runs into the back of said stuck product carrier.
According to a simple embodiment of the transport system according to the present invention, the primary part can be arranged on the base plate, especially on the lower surface of said base plate. This means that such a primary part can be arranged in a simple manner and that it will easily be accessible when maintenance work or the like has to be carried out. In addition, the secondary part can be arranged in directly opposed relationship with the primary part on the slide way, only a small gap remaining between these two parts.
In cases in which the base plate of the product carrier is sufficiently high, the primary part can additionally be arranged in the base plate such that it is at least partially embedded therein. If the base plate is sufficiently high, the primary part can also be embedded completely therein and terminate such that its lower surface is flush with the lower surface of the base plate. The product carrier can in this way be arranged very close to the slide ways, when e.g. also the secondary part is arranged in an embedded mode of arrangement, so that the total construction height of the transport system can be reduced. In addition, the primary and the secondary part are largely protected against damage in this way.
The linear motor drive unit can be implemented as an asynchronous motor or a synchronous motor. The motor used is preferably an asynchronous motor.
Since the primary part is associated with the product carrier or base plate, a suitable voltage or power supply must be provided. According to one embodiment, a voltage supply unit extends along the slide way and is especially arranged on this slide way and the product carrier is in contact with the voltage supply unit via a sliding-contact means. Such voltage and power supply means for moving objects can be realized in many different ways and a great variety of realizations are known in practice. In the case of the transport system according to the present invention, the voltage supply unit can be implemented e.g. as a conductor rail along which a sliding contact projecting from the product carrier can be moved.
The slide way of the transport system according to the present invention can be realized in different ways. DE 298 16 285, which is owned by the same applicant, describes e.g. horizontally and vertically arranged slide ways with suitable guide means for the product carriers. The base plates are oriented horizontally or vertically in a corresponding manner. Such horizontal and vertical arrangements with suitable holders and guide means according to DE 298 16 285 can also be used in the transport system according to the present invention.
In the described embodiment of the transport system according to the present invention, the slide ways are formed by a pair of slide rails held in spaced relationship with one another by a plurality of support sections set up substantially vertically on a foundation. Instead of the support sections, it is also possible to use, in a similar way, support posts having a structural design which is similar to that described in DE 298 16 285.
In order to bridge the free space between the support sections, a cover section can be arranged between the support sections. This cover section can extend along the slide ways in the whole transport system.
Since the cover section faces substantially the lower surface of the base plate or product carrier, the secondary part or the secondary parts can be arranged on the cover section along the slide way. In the case of synchronous motors, magnets and especially profile magnets are used
Mayer Otto
Wohlfarth Klaus
Bidwell James R.
Coats & Bennett P.L.L.C.
Cooper Power Tools GmbH
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