GB2200799A

GB2200799A - Sensing conveyed objects

Info

Publication number: GB2200799A
Application number: GB08701979A
Authority: GB
Inventors: Gordon Taylor; Brendan Patrick Quirke
Original assignee: G A D DESIGN ASSOCIATES
Current assignee: G A D DESIGN ASSOCIATES
Priority date: 1987-01-29
Filing date: 1987-01-29
Publication date: 1988-08-10
Also published as: GB8701979D0

Abstract

There is described a device for sensing the passage of a plurality of irregularly spaced objects such as eggs along a path such as a conveyor. Above the conveyor (2) is mounted a gate (12) pivoted about a horizontal axis (11) so as to be lifted by objects passing along the conveyor (2). A switch (16) provides an electrical output to a counter when the gate (12) is lifted, the switch (16) being operated by a cam (17, 18) so that initial movement of the gate (12) trips the switch (16) but further movement of the gate does not affect the switch. Successive deflectors (20) arranged upstream of the gate along the conveyor (2) on alternate sides urge the objects in opposite directions laterally of the conveyor (2) to prevent a plurality of objects reaching the gate (12) simultaneously. <IMAGE>

Description

SENSING DEVICE The present invention relates to sensing devices and is particularly concerned with the detection of objects moving along conveyors in order to count the objects as they pass.

In the intensive production of eggs, hens are kept in cages and as eggs are laid they move along ramps out of the cages to be deposited on a conveyor for collection. It will be understood that the eggs will be by no means evenly spaced on the belt, and will often be in groups, since there is no exact synchronism in the egg production rates between invividual hens.

Devices are known which use a light beam extending across the egg conveyor to detect the eggs, but such devices suffer from the disadvantage that in the dusty conditions prevailing in hen-houses, the optical path is often obscured by dirt collected on lenses, thus putting optical sensing devices out of action.

According to a first aspect of the present invention, a device for sensing the passage of objects along a path comprises a gate disposed adjacent the path so as to be contacted by objects moving along the path, the gate being mounted for movement from a rest position to a deflected position and switch means being associated with the gate in such a way that an initial part of the movement of the gate causes the switch means to operate.

According to a second aspect of the invention, a sensor device as defined above further includes a number of deflectors positoned along the path so as to contact objects moving along the path and urge them laterally of the path, alternate deflectors being arranged to urge the objects in opposite lateral directions with respect to the path.

An embodiment of the present invention will now be described in detail, with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal sectional elevation of the counter; Fig. 2 is an end view of the counter from the exit end; and Fig. 3 is a schematic plan view showing the ordering device.

Referring now to the figures, there is seen a counter 1 adapted for fitting over a conveyor belt 2. The counter has a channel-shaped lower body part 3, which includes a base 4 situated beneath a portion of conveyor 2, and sidewalls 5,6 extending along opposite sides of the conveyor 2.

An upper body part 7 of inverted channel shape is fixed to the lower body part 3, and extends between the sidewalls 5 and 6. The upper body part comprises side panels 8 and 9 and a top panel 10.

Extending between the side panels 8 and 9 is a bar 11 on which a flap is inclined downwardly from bar 11 in the direction of travel of the conveyor belt (right to left in Figs. 1 and 3), the edge portion 12a of the flap 12 remote from bar 11 being more steeply inclined than the main part 12a of the flap. A supporting stud 13 extending from side panel 9 supports the flap 12, with its edge portion 12a terminating at a predetermined height H above the conveyor belt 2.

Extending upwardly from the flap 12 at the junction between its main part 12b and edge portion 12a is an actuator 14, which contacts the control arm 15 of a microswitch 16. Microswitch 16 is connected to any conventional electronic counting device, to count one object each time the switch is operated.

As may be appreciated from Fig. 1, a clockwise rotation of the flap 12 will cause the actuator 14 to rise substantially vertically, since the pivot axis of the flap 12 about bar 11 is substantially level with the centre of the actuator 14.

The actuator 14 has an inclined ramp 17 at its upper end, and a substantially vertical major portion 18. The microswitch 16 is so positioned that, when the flap 12 rests on the stud 13, the operating arm 15 of the microswitch 16 contacts the ramp portion 17 of the actuator 14, for reasons to be explained.

In use, the counter is positioned so that a portion of conveyor 2 extends over the base 4 of the lower body part 3 and ih% j objects such as eggs pass along the conveyor from right to left as seen in Fig. 1. The height H is arranged so that even the smallest objects will strike the edge portion 12a of the flap 12 as they pass, and the inclination of the edge portion 12a ensures that each time an object passes beneath the flap 12, the flap is lifted.

Clearly, objects of different height will lift the flap 12 by different amounts. The microswitch however can accommodate only a limited travel of its operating arm 15 and since it is necessary to count every object, the actuator 14 is configured so that during the initial upward movement of the flap 12, the operating arm 15 is deflected through its switching travel by the ramp 17. Thereafter, the operating arm 15 contacts the major portion 18 of the actuator 14, and further upward movement of the flap 12 causes no further appreciable deflection of the operating arm 15 of the microswitch 16.

Clearly, the most efective configuration of the major portion 18 of the actuator is a cylindrical surface centred on the bar 11, as this will cause no deflection of the operating arm during rotation of flap 12.

It has been found that a planar major portion 18 is simpler to fabricate and is in practice as effective.

To ensure that the objects on the conveyor are presented singly to the flap 12, two laterally-extending deflectors 20,21 are provided on the inner surfaces of the sidewalls 5 and 6 respectively.

The deflectors may have cushioned faces, to avoid damaging fragile objects. The deflector 20 is positioned upstream of deflector 21 and serves to urge objects on the conveyor belt to.the left, seen in the stream direction S. The effect of the sideways deflection is to ensure that, of two objects arriving simultaneously, one is caused to lag slightly behind the other.

The objects then pass into contact with the second deflector 21, which urges them to the right (seen again in the stream direction S) and this causes the objects to adopt a single file configuration as they pass the deflector 21. The objects are then contacted by the flap 12 for counting.

The staggered arrangement of the deflectors 20 and 21, forming a "chicane", has been found to be superior to an arrangement of two deflectors opposite each other defining a gap through which only one object may pass, since such arrangements are'prone to form a jam when two objects arrive simultaneously, building up a large backlog of objects on the belt.

While two deflectors 20 and 21 are adequate to arrange the objects on the conveyor into a single file at normal conveyor speeds, it is possible that at higher conveyor speeds a series of three or more deflectors upstream of. the gate may be required to order the objects. The deflectors will urge the objects laterally of the belt, successive deflectors urging the objects in alternate lateral directions. It may be advantageous in some situations to arrange one or more series of deflectors at spaced locations upstream of the gate.

While the counter has been described in relation to one specific embodiment, it is to be understood that modifications in the constructional detail and configuration are possible without departing from the scope of the invention. The counter, though primarily intended for counting eggs, may be used for counting other objects passing along a conveyor, and the conveyor need not necessarily be a belt.

Claims

1. A sensing device for detecting the passage of objects along a path, comprising a gate disposed adjacent the path so as to be contacted and deflected by objects moving along the path, the gate being mounted for pivotal movement from a rest position to a deflected position and a switch associated with the gate in such a way that an initial movement of the gate from its rest position causes the switch to operate.

2. A sensing device according to claim 1, wherein the gate is situated above the path and is pivotally mounted about a horizontal axis so as to be raised out of its rest position by objects passing along the path, a cam surface mounted on the gate being engaged by an operating element of the switch, and the cam profile being such that movement of the operating element of the switch is effected during an initial movement of the gate from its rest position, the operating member being held substantially stationary during the remainder of the motion of the gate to its deflected position.

3. sensing the passage of the twice deflected objects at a sensing station downstream of the second deflecting station, the sensing station comprising a gate disposed adjacent the path so as to be contacted and deflected by objects moving along the path, the gate being mounted for pivotal movement from a rest position to a deflected position and a switch associated with the gate in such a way that an initial movement of the gate from its rest position causes the switch to operate 10. A sensing device substantially as herein described with reference to the accompanying drawings.

3. A sensing device according to claim 1 or claim 2, wherein the gate extends from one side of the path across half the width of the path and objects passing along the path are deflected laterally of the path towards the gate before contacting the gate.

4. A sensing device according to claim 3, wherein objects moving along the path are deflected towards the gate by a first deflector plate mounted upstream of the gate, the plate extending downstream from the other side of the path and forming an acute angle with the side of the path.

5. A sensing device according to claim 4, wherein at least one further deflector plate is arranged upstream of the first deflector plate, so as to extend inwardly and downstream of the path from the said one side of the path.

6. A sensing device according to claim 5, wherein a series of deflector plates extending from alternate sides of the path is arranged upstream of the gate.

7. A sensing device according to any preceding claim wherein a conveyor constitutes the path.

8. A sensing device according to any of claims 1 to 6, wherein the path is constituted by a chute or ramp.

9. A method of sensing a plurality of irregularly spaced objects passing along a path, comprising the steps of:

1. deflecting the objects towards one side of the path at a first deflecting station,

2. deflecting the objects towards the other side of the path at a second deflecting station downstream from the first deflecting station, and