Conveyors: power-driven – Conveyor section – Pusher conveyor and separate load support surface
Reexamination Certificate
1999-01-25
2001-04-17
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor section
Pusher conveyor and separate load support surface
C198S844200, C024S03100H
Reexamination Certificate
active
06216849
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a belt assembly which, in operation, can be tensioned along a path, comprising a belt having a toothed surface and an oppositely located back surface, and one unit or a plurality of units fastened to the belt on the side of the back surface.
Such a belt assembly is utilized in practice, for instance in apparatuses for preparing items to be mailed, for the purpose of conveying postal items located on a transport surface. The unit fastened to the belt is often a carrier. The carriers extend through the slots provided in the transport surface and move forward the postal items to be conveyed as required, for instance stepwise.
The advantages of a belt assembly over the conveyor chains utilized heretofore, such as link chains of the bicycle-chain type, are important.
Firstly, belts make less noise and are lighter than chains. Owing to the smaller mass of the belts, the acceleration and retardation forces are smaller, so that the drives and slip-action clutches can be of lighter construction.
Secondly, unlike chains, belts need not be lubricated. Lubricated chains entail the risk of the postal items becoming dirty.
However, the belts used heretofore in apparatuses for preparing items to be mailed also have a number of disadvantages which are not inherent to conveyor chains and form an obstacle to the progressive introduction of the belt.
The most important disadvantage is the fact that the belts must be manufactured as endless belts with the carriers provided at predetermined positions. The carriers are connected to the back surface of the belt, for instance by means of glue or by ultrasonic welding, and the end parts of the belt are similarly connected to each other. This means that both the length of the endless belt and the position of the carriers are fixed and that for each type of apparatus for preparing items to be mailed, specific belts must be manufactured and kept in stock for service.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a belt assembly without the disadvantages described hereinabove.
To that end, the belt assembly of the type mentioned in the preamble is characterized in that, in the area of at least one of the units mentioned, parts of the belt are bent out of the path of the belt assembly in the direction of the unit, the unit mentioned comprising at least one retention element which is in engagement with the toothed surface of the bent belt parts.
As with conveyor chains, units which are attached to the belt in this manner can be displaced or removed as required. Further, use can be made of standard commercially available belts without projections formed thereon by welding, which are considerably cheaper than the belts provided with projections, to be manufactured in accordance with stated specifications. Thus, according to the proposal of the present invention, a belt assembly is provided which combines the advantages of normal conveyor chains with the advantages of the conventional conveyor belts, with increased flexibility regarding the possible positions of the units on the belt and with a substantial reduction of the cost price. In addition, a loose unit provides the advantage of greater freedom in construction and the different designs thereof. A further advantage is that the position of the unit can be chosen accurately because it is related to the teeth of the belt. Further, such a unit can be arranged without special costly tools and, because the retention element engages the toothed surface, a firm connection between the belt and the unit can be obtained without the belt having to be clamped together at the point of the connection.
In particular when the belt assembly is utilized for positioning operations, it is particularly favorable when, in accordance with a further elaboration of the invention, the position of the or each retention element as well as the contour of parts of the unit against which the back surfaces of the bent belt parts abut are so designed that the teeth of portions of the toothed belt adjacent to the unit on either side thereof define a toothed profile extending over both belt portions, the pitch between teeth of one belt portion and the other belt portion being a whole multiple of the pitch of successive teeth of each belt portion.
Such a belt assembly can be passed over a toothed pulley without any difficulty, while maintaining the positioning accuracy.
If it is desired that the portion of the toothed belt assembly at the point where the unit is located passes through greater angles over a toothed pulley and, in particular, if that pulley moreover has a relatively small diameter, it is advantageous if the contour of parts of the unit against which the back surfaces of the bent belt parts abut are moreover so designed that the pitch between teeth of one belt portion and the other belt portion is also a whole multiple of the pitch of successive teeth of each belt portion when those belt portions follow a path bent in such a manner that the toothed side of the belt is located on the inside.
When bending the belt assembly from a straight path, such that the toothed side is located on the inside, the neutral plane of the belt assembly, at the point of the unit, forms a continuation of the neutral plane of the belt portions on either side of the unit, and it is located, in a direction perpendicular to that plane, at the same distance from the toothed side of the belt, or at least the continuations thereof, as the neutral plane of the belt portions on either side of the unit. This property can be obtained relatively simply with the belt assembly according to the invention because the belt portions may be bent out of the path at a very slight distance from each other and thereby the relative displacements of the belt portions adjacent to the unit upon bending of the belt assembly in the area of the unit can be simply adjusted to corresponding relative displacements upon a comparable bending of an uninterrupted belt portion, through a suitable design of the contours against which the bent belt portions abut.
As described above, the belt assemblies used heretofore have the disadvantage that, at least in apparatuses for preparing items to be mailed, they can only be used in endless form. Apart from the objection that endless belts must be kept in stock in a variety of matching lengths and must be especially manufactured to meet the stated specifications, the assembly and disassembly of endless belts is cumbersome and laborious. Further, in practice the repair of endless belts is impossible or possible only with special tools.
In order to circumvent the objections of an endless belt, it is particularly advantageous when the toothed belt is interrupted and when belt end parts on either side of the interruption form the bent belt parts.
The belt end parts can diverge relative to each other in the direction of their ends. This provides the advantage that the distance over which the belt end parts as well as the unit project from the back side of the adjacent belt portions can be limited inasmuch as the belt end parts do not project perpendicularly relative to the path determined by the belt portions. Thus, a unit of relatively flat design can be obtained.
A unit of particularly flat design can be obtained if the belt end parts are bent in substantially opposite directions.
When the unit is provided with channels for receiving the belt end parts, these channels comprising open flanks such that the bent belt end parts can be slipped into and out of the unit in both lateral directions, a very simple method of assembling the unit and the belt parts to be connected thereto is obtained. The connection between two belt end parts is effected in simple manner by slipping the belt end parts sideways into the channels.
Further, this provides the advantage that it is not necessary for parts of the unit to project in lateral direction beyond the toothed belt parts confined within the unit. Thus, a toothed belt assembly can be obtained which occupies little space in lat
Burns Doane Swecker & Mathis L.L.P.
Hadewe B.V.
Valenza Joseph E.
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