GB2326488A

GB2326488A - Weighing apparatus

Info

Publication number: GB2326488A
Application number: GB9713042A
Authority: GB
Inventors: Kevin Hurst Harmon
Original assignee: SPARC INSPECTION SYSTEMS LIMIT
Current assignee: SPARC INSPECTION SYSTEMS LIMIT
Priority date: 1997-06-21
Filing date: 1997-06-21
Publication date: 1998-12-23
Also published as: GB9713042D0

Abstract

A weighing apparatus for use with a roller track conveyor 1 comprises a weighing table 13 and support means 15. The weighing table 13 is movable upwardly and downwardly between a lower inactive position and an active upper position. The support means 15 is distributed over the weighing table and extends upwardly therefrom for supporting an item 7 to be weighed at a plurality of spaced locations. The support means 15 may be dimensioned to extend between adjacent rollers 5 and may comprise a plurality of spaced pins that extend above the rollers 5 when in the active position. Means may be provided to detect the arrival of an item 7 to be weighed and automatically move the weighing table 13 to the active position.

Description

WEIGHING APPARATUS This invention relates to weighing apparatus and more particularly is concerned with apparatus for weighing items, such as packages, travelling along a roller track conveyor.

A roller track conveyor comprises a plurality of rollers which extend transverse to the direction of movement of the items to be weighed to be conveyed therealong, the rollers being spaced a predetermined distance apart. Means may be provided for rotating one or more of the rollers so as to convey items to be weighed along the conveyor. When it is required to weigh an item travelling along the conveyor it is generally necessary to insert a weighing station into the conveyor. This is often inconvenient in that it requires that the conveyor is interrupted to permit insertion of the weighing station and it is expensive in that means is required to move the items individually onto and off the weighing station.

It is therefore an object of the present invention to provide a simple and effective weighing apparatus for use with a roller track conveyor.

According to the present invention there is provided a weighing apparatus for use with a roller track conveyor, the weighing apparatus comprising a weighing table which is movable upwardly and downwardly between a lower inactive position and an active upper position and support means distributed over the weighing table and extending upwardly therefrom for supporting an item to be weighed at a plurality of spaced locations.

The support means may be dimensioned to extend between adjacent rollers of a roller track conveyor. The support means may extend in both the longitudinal and lateral directions of the conveyor. The length of the support means may be such as to be positioned below the upper surface of the rollers in the lower position of the weighing table and so as to protrude above the upper surface of the rollers when the weighing table is in the upper position.

The support means may be in the form of a plurality of pins extending upwardly from the weighing table. Alternatively the support means may be elongate, the plurality of support means being arranged substantially parallel to each other.

The support means may terminate substantially in a single plane.

The weighing table may be moved between the lower and upper positions by hydraulic or pneumatic means. Alternatively, the weighing table may be moved between the lower and upper positions by electrical or mechanical means.

Means may be provided for detecting the arrival of an item to be weighed and for moving the weighing table to its upper position in response to such a detection.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a diagrammatic side view, partly in crosssection, of one embodiment of a weighing apparatus according to the present invention positioned beneath a roller track conveyor; and Figure 2 is an end view, partly in cross-section, of the weighing apparatus and roller track conveyor shown in Figure 1.

The figures show a conventional roller track conveyor 1 mounted on legs 3, the conveyor incorporating a plurality of rollers 5 which are rotated to convey an item 7 to be weighed along the conveyor.

Positioned beneath the conveyor 1 at a suitable location is a weighing apparatus 9. The weighing apparatus comprises a support frame 11 or the like on which is supported a weighing table 13 by way of one or more load cells (not shown) in a conventional manner. The weighing table 13 is movable between a lower inactive position and an upper active position, for example by pneumatic or hydraulic cylinders 12 controlled by means provided in a display/controller 17.

Protruding upwardly from the upper surface of the weighing table 13 is a plurality of support means in the form of support rods 15, the support rods extending upwardly between adjacent rollers 5. The support rods 15 are arranged in both the longitudinal and lateral directions of the conveyor. The support rods are all substantially of the same length such that the free ends thereof lie substantially in a plane. If desired, the support rods can be replaced by alternative support means such as a plurality of elongate members (not shown) extending between adjacent rollers, the elongate members being arranged substantially parallel to each other.

The length of the support rods 15 is such that when the weighing table 13 is in the lower position thereof the upper ends of the support rods are beneath the upper surface of the rollers 5, but when the weighing table is in the upper position as illustrated in the figures the upper ends of the support rods protrude above the upper surface of the rollers for supporting an item 7 to be weighed. The range of movement of the support rods may be, for example, in the range from 15 to 25 mm.

The display/controller 17 is provided for various functions such as displaying the weight of each item, indicating over- or under-weight items, and initialising zero weight.

In operation of the weighing apparatus, the weighing table 13 is initially in its lower position with the display 17 indicating zero weight and with the roller track conveyor 1 operating to convey items to be weighed along the conveyor.

Suitable means, such as an opto-electronic detector (not shown), is provided for detecting the progress of items 7 to be weighed along the conveyor 1. When an item is detected the weighing table 13 is raised to its upper position in order to raise the item 7 from the rollers 5.

The weight of the item is determined after a predetermined time lapse in order for the detected weight to stabilise.

The predetermined time lapse may be varied if desired.

If the weight of the item 7 is determined to be acceptable, the weighing table is returned to its lower position and the item continues on its way along the conveyor.

If the weight of the item 7 is determined not to be acceptable, a reject signal is initiated to actuate a reject pusher (not shown) to remove the item from the conveyor 1 and/or to issue an audible and/or visual alarm if desired. The reject signal can be delayed if desired in order to remove the item from the conveyor 1 at a point downstream of the weighing apparatus. For example, the reject signal can be delayed by up to 20 seconds or more.

The weighing table 13 is returned automatically to its lower position at a suitable time in the reject cycle or can be returned manually by use of a reset push-button (not shown).

Claims

1. A weighing apparatus for use with a roller track conveyor, the weighing apparatus comprising a weighing table which is movable upwardly and downwardly between a lower inactive position and an active upper position and support means distributed over the weighing table and extending upwardly therefrom for supporting an item to be weighed at a plurality of spaced locations.

2. A weighing apparatus as claimed in claim 1, wherein the support means is dimensioned to extend between adjacent rollers of a roller track conveyor.

3. A weighing apparatus as claimed in claim 1 or 2, wherein the support means extends in both the longitudinal and lateral directions of the conveyor.

4. A weighing apparatus as claimed in any preceding claim, wherein the length of the support means is such as to be positioned below the upper surface of the rollers in the lower position of the weighing table and so as to protrude above the upper surface of the rollers when the weighing table is in the upper position.

5. A weighing apparatus as claimed in any preceding claim, wherein the support means is in the form of a plurality of pins extending upwardly from the weighing table.

6. A weighing apparatus as claimed in any one of claims 1 to 4, wherein the support means is elongate, the plurality of support means being arranged substantially parallel to each other.

7. A weighing apparatus as claimed in any preceding claim, wherein the support means terminates substantially in a single plane.

8. A weighing apparatus as claimed in any preceding claim, wherein the weighing table is moved between the lower and upper positions by hydraulic or pneumatic means.

9. A weighing apparatus as claimed in any one of claims 1 to 7, wherein the weighing table is moved between the lower and upper positions by electrical or mechanical means.

10. A weighing apparatus as claimed in any preceding claim, wherein means is provided for detecting the arrival of an item to be weighed and for moving the weighing table to its upper position in response to such a detection.

11. A weighing apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.