GB2105479A - >A filling and weighing machine - Google Patents

Abstract

A filling and weighing machine has a pivotable chute (20) for dispensing material into containers on platforms (21). The platforms are supported by counter-weighted balance arms (10) and are connected only by flexible lines (31, 32) to the chute. When a container is filled to a preset weight, its platform drops thereby causing the chute to pivot and dispense material into another container. Linkages in the machine are uncomplicated and of low inertia allowing the machine to dispense accurately weights as low as 500 grams. <IMAGE>

Description

SPECIFICATION An improved filling machine The present invention relates to a filling and weighing machine. In particular, the invention is directed to apparatus for dispensing predetermined weights of material into containers.

The use of automatic filling and weighing machines was popularized in the grain industry around the turn of the century. Today, they are still used extensively in agricultural and industrial fields, particularly packaging.

Known filling machines generally comprise a pair of spouts adapted to dispense material into respective containers, and feeding means to varying the flow of material from one spout to the other, such feeding means being automatically actuated when the weight of material in the container being filled reaches a predetermined value. The feeding means can comprise a pivotable chute as disclosed in U.S. Patent Nos.

321,209 and 364,407, or a deflection plate as disclosed in U.S. Patents 293,129; 302,697 and 669,607. A disadvantage of these known devices is that the flow of material impinges on the chute or deflection plate in such a manner as to oppose the movement of the chute or plate to alternate the flow of the material between spouts. Thus, a greater force is required to effect the changeover, and inaccuracies in the weights of the dispensed material may occur as a consequence, particularly for weights less than a few kilograms.

Australian Patent No. 485,455 discioses a filling machine having two pivotable platforms, one end of each platform being adapted to support a container to be filled, while the other end of each platform supports a predetermined weight.

Mechanical means are provided to divert the chute from one container to the other when the one container has been filled to the set weight. As in the above referenced U.S. patents, the means for diverting the chute from one container to the other in the machine disclosed in Patent No. 485,455 comprises a complex arranbement of connecting rods, push rods, pivoting levers and bevel gears.

When the container at one end of one of the pivotable platforms is filled to the predetermined weight, that end of the platform sinks thereby causing the other end two rise. The other end of that platform has a connecting rod attached thereto which, as it rises, pushes against a stop on a push rod. The push rod, in turn, causes a rocker bar to pivot about a horizontal axis. By means of a bevel gear, the rotation of the rocker arm about a horizontal axis is transformed into rotation of a shaft about a horizontal axis. The shaft is connected to the material feeding chute which is thereby rotated about a vertical axis from the filled container to the container to be filled.

The above described complex system of linkages and gears gives rise to a high degree of friction and inertia in the means for diverting the material feeding chute. As a result, the known apparatus is not entirely suitable for filling container to weights less than 5 kilograms, since it becomes inaccurate and the weight of a filled container may not be sufficient to actuate the means for diverting the chute to the unfilled container.

Furthermore, the complex linkage arrangement gives rise to relatively high construction and retail costs.

It is an object of the present invention to overcome or substantially ameliorate the above-described disadvantages by providing apparatus for dispensing predetermined quantities of material into containers, said apparatus comprising uncomplicated, but effective, means for diverting the material from one container to the other.

According to the present invention, there is disclosed apparatus for dispensing predetermined weights of material into containers, said apparatus comprising two pivotable support members, one end of each support member providing a support for a respective container to be filled, the other end of each support member providing a predetermined counterweight to determine the weight of material to be dispensed into said respective container, each said support member being pivotable about an axis between its ends; a material feeding chute adapted to dispense material alternately into each said container; and means for directing said feeding chute from one container to the other when said one container is filled to the predetermined weight; characterized in that said means for directing said feeding chute comprises two flexible lines, each connected between a respective one of said support members and a respective end of a directing member pivotable about an axis between its ends, said directing member being connected to said feeding chute, whereby each said flexible line causes said directing member to pivot in response to movement of the corresponding support member in one direction when the respective container is filled to thereby direct said feeding chute to the other container.

Preferably, said flexible lines are chain or string.

Preferably, the directing member is connected directly to the feeding chute and both are pivotal about the same axis so that said lines provide a direct response between movement of said support members and pivoting of said feeding chute. Since, there are no complex linkage arrangements between the support members and the feeding chute, friction and inertia are reduced to a minimum thereby allowing small weights to be dispensed.

Preferably, the directing member is counterweighted so that its centre of gravity passes from one side of the pivoting axis to the other during pivoting. The directing member is designed so that the initial pivotal movement of a supporting member is sufficient to transfer the centre of weight from one side to the other.

Thereafter, the directing member continues to pivot to a rest position under its own counterweight. The counterweight biases the directing member in a rest position on one side until the line on the opposite side exerts a sufficient force to pivot the directing member and transfer the centre of gravity to the other side of the pivot axis.

Notwithstanding any other forms that may fall within its scope, a preferred form of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a schematic front elevational view of a filling machine according to the preferred embodiment of the present invention.

Fig. 2 is a schematic side elevational partial view of the filling machine of Fig. 1.

Fig. 3 is a schematic side elevational partial view of the filling machine of Fig. 1, showing operation thereof.

The filling machine of the preferred embodiment comprises two pivotable support members, such as scale beams 10 and 11. For simplicity, Fig. 3 shows only scale beam 10 in detail, scale beam 11 being identical in construction. The scale beam 10 is pivotable about an axis at pivot point 1 2. Attached to one end of the scale beam 10, there is provided a support 21 for a container (not shown) to be filled.

At the opposite end of the scale beam 10, there is provided a weight 22 whose position along the scale beam can be changed to vary the effective counterweight provided to the support 21.

The container to be supported by support 21 is filled with material via feeding chute 20 which cooperates with a baffle arrangement which defines two outlets leading into connecting chutes 1 8, 1 9.

As illustrated in Fig. 2, material passing into the feeding chute 20 impinges on the front sloping side thereof and consequently, the force of the material flow does not hinder the pivoting of the chute 20 from side-to-side. Increased accuracy is achieved thereby allowing the machine to be used for dispensing weights as low as 500 grams.

Preferably, the connecting chutes 1 8, 19 are provided with flexible end portions 1 6, 1 7 to accommodate changes in the positions of the outlets 14, 1 5 of the chutes. The flexible end portions can incorporate dust covers to dustproof the machine, a preferred feature when dispensing powdered goods.

Two flexible lines, such as thin chains 31, 32 are connected respectively between scale beams 10, 11 and opposite ends of a pivotable directing member such as beam 30. The chains 31, 32 are connected to rigid vertical rods 41,42 which can incorporate stops (not shown) to limit upward and downward movement of the scale beams. The beam 30 is connected directly to the feeding chute 20 so that rotational movement of the beam 30 about its pivot axis causes the feeding chute 20 to pivot. The beam 30 has a counterweight 35 arranged so that as the beam pivots through a horizontal position, the centre of gravity of the combined beam/counterweight passes from one side of the pivot axis to the other.

Operation of the filling machine will now be described. Initially, it is assumed that the containers on both scale beams are empty. With beam 30 in position 1, the delivery end of the feeding chute 20 will be orientated towards connecting chute 1 8 so that material passing through the feeding chute 20 will fill the container on scale beam 1 0. When the container on scale beam 10 is filled to a weight determined by the value and position of weight 22 on the opposite end of that beam, scale beam 11 will tilt so that the container support end drops. The drop in the scale beam 11 is transferred by a chain 31 to beam 30.When the upper end of beam 30 is pulled down by a predetermined distance A, the centre of gravity of the combined beam and counterweight crosses the centre line and thereby causes the beam 30 to continue rotating in that direction to a rest position. In practice, the distance A need only be a short distance as the inertia of the counterweight keeps it moving past the centre line. A short scale beam 30 can therefore be used. The material passing through feeding chute 20 is now directed to the container on scale beam 11.

While the container on scale beam 11 is being filled, the filled container on scale beam 10 can be removed and replaced by an empty container. The container end of beam 10 would then rise but this upward movement would not be transferred to beam 30 by chain 31 since it is flexible. The chains 31, 32 only transfer downward movement of the scale beams to beam 30.

When the container on scale beam 11 is filled to the required weight, the filling machine follows a procedure similar to that described above so that the feeding chute 20 is redirected from the connecting chute 1 9 back to connecting chute 18, and the material passing therethrough commences to fill the empty container on scale beam 10.

The present invention can be used to dispense granular or powdered products such as root crops and fruit, as well as grain, fertilizers, chemicals, sugar, foodstuffs and other such materials.

Furthermore, the invention can be adapted to dispense bulk liquids.

The present invention requires no electric power and can be operated "in the field".

Two flexible lines, which can be chains, strings, cords, ropes or cables, provide the linkage between the scale beams and the feeding chute.

Consequently, friction and inertia are minimized and the invention can be used to dispense quantities even less than 1 kilogram. Moreover, the flexible lines involve low cost and require little, if any, maintenance. The line linkages can be easily replaced with stronger lines and the filling machine can be adapted to dispense heavy weight quantities over 50 kilograms.

The foregoing describes one embodiment of the present invention and modifications, obvious to those skilled in the art, may be made thereto without departing from the scope of the invention as claimed hereafter. For example, to assist in dispensing material of poor flow characteristics, an auger can be incorporated into the machine to force feed the material into the input chute 5, from where it is gravity fed through the chutes into the containers to be filled.

The machine of the present invention can also be incorporated into a conveyor assembly whereby containers are automatically positioned on the supports 21 and removed when filled. The automatic removal can be triggered by the tilting of the respective scale beam.

As a safety measure, spring can be inserted between flexible lines 31, 32 and the beam 30.

The springs are of such tension that they are closed during normal operation, but will expand if an excessive load is applied thereby prevent breakage of the flexible lines.

Claims (10)

1. Apparatus for dispensing predetermined weights of material into containers, said apparatus comprising: a pair of pivotable support members, one end of each support member providing a support for a respective container to be filled, the other end of each support member providing a predetermined counterweight to determine the weight of material to be dispensed into said respective container, each said support member being pivotable about an axis between its ends; a material feeding chute adapted to dispense material alternately into each said container; and means for directing said feeding chute from one container to the other when said one container is filled to the predetermined weight; characterized in that said means for directing said feeding chute comprises two flexible lines, each connected between a respective one of said support members and a respective end of a directing member pivotable about an axis between its ends, said directing member being connected to said feeding chute, whereby each said flexible line causes said directing member to pivot in response to movement of the corresponding support member in one direction when the respective container is filled to thereby direct said feeding chute to the other container.

2. Apparatus as claimed in claim 1 , wherein material entering said feeding chute impinges on a side of said chute so that the material flows does not substantially hinder pivotal movement of said feeding chute.

3. Apparatus as claimed in claim 2, wherein said flexible lines comprise lengths of chain.

4. Apparatus as claimed in claim 2, wherein said flexible lines comprise lengths of string.

5. Apparatus as claimed in claim 1, wherein the directing member is connected directly to the feeding chute, said directing member and feeding chute being pivotable about the same axis, whereby said feeding chute is directly responsive to said one end of said support members via said flexible lines.

6. Apparatus as claimed in claim 5, wherein said directing member is counterweighted so that its centre of gravity passes from one side of the pivoting acis to the other during pivoting.

7. Apparatus as claimed in claim 6, wherein passages for the flow of material from said feeding chute to said containers are dust proofed.

8. Apparatus as claimed in claim 7, wherein an auger is provided to force feed material into said feeding chute.

9. A conveyor assembly including an apparatus as claimed in claim 1.

10. Apparatus for dispensing predetermined weights of material into containers, said apparatus being substantially as described herein with reference to the accompanying drawings.