A combination weighing machine The present invention relates to a weighing machine comprising a number of weighing scales for weighing a material batch arranged in each of the weighing scales, and a number of memory scales, and means for emptying the weighing scales and transferring the weighed material batches from the weighing scales to the memory scales, said memory scales having means for discharging the material batches from each of these into a collection means intended therefor, and wherein the weighing machine has means for storing and calculating data concerning the weight and allocation of the individual material batches with a view to selecting and emptying the memory scales that contain material batches that combine to have a total weight that is close to a predetermined, desired total weight.

Today such weighing machines are used for dividing bulk goods into product batches having a desired weight whereby the smaller batches can be transferred to eg a packaging apparatus that packs the individual batches.

In these weighing machines that are most often designated combination weights, a plurality of weighing scales are often used that are each configured for weighing material batches, and the machines have a central calculator unit arranged for selecting combinations of the weighed material batches that yield exactly the desired weight or a weight that is close to the desired weight. Hereby it is possible to obtain relatively high production rates depending ia on the number of weighing scales.

Today these combination weights are continuously developed with a view to increasing the production rates.

For instance from US patent No 5,048,623 such combination weight is known wherein each weighing scale is configured with an additional memory scale in such a manner that a filled weighing scale can be emptied into the associated memory scale whereby the weighing scale can quickly be filled with another batch to be weighed. Thus a reduction of the inactive periods of the weighing scale increases the productivity.

EP patent application No 196,552 teaches another type wherein the memory scales can be displaced stepwise underneath the weighing scales whereby an empty memory scale can be displaced below a filled weighing scale where the memory scale is subsequently stopped and the batch in the weighing scale is transferred to the memory scale.

In the light of this it is the object of the present invention to provide a weighing machine of the latter type wherein, ceteris paribus, it is enabled to further increase the productivity and accuracy of measurement.

This is obtained according to claim 1 by providing a substantially constant mutual velocity between the weighing scales and the memory scales. Hereby it is avoided ia that vibrations due to repeated braking and accelerations cause scales with material batches to be eliminated which results in quicker and more accurate weighing of the material batches positioned in the weighing scales.

In accordance with a preferred embodiment whereby combination weights can be constructed that have a relatively high productivity by use of relatively few weighing scales and memory scales, the weighing machine comprises at least two weighing scales and two memory scales, and wherein the means for transferring the material batches from the weighing scales to the memory scales are configured in such a manner that a material batch located in any of the weighing scales can be transferred to any of the memory scales.

The functionality of ensuring that weighed batches within the weighing scales can be transferred to the memory scales can be obtained in a simple manner by configuring the weighing scales with a discharge opening, and by the weighing machine having a movement mechanism arranged with a view to displacing the weighing scales relative to the memory scales whereby each of the memory scales is sequentially caused to be moved past the discharge opening on the weighing scales.

In this connection, the weighing scales and the memory scales can advantageously be arranged annularly with centers in a common center axis wherein the memory scales are located underneath the weighing scales. Hereby a simple construction of the machine is obtained.

In this context, the weighing scales are advantageously mounted stationarily on the weighing machine, and the memory scales are mounted rotatably about the center axis. Hereby the relative movement between the memory scales and the weighing scales is accomplished, while simultaneously the stationary weighing scales can perform relatively accurate weighing.

Further advantageously, means are configured for indicating which memory scales are empty, and means for indicating the position of the empty memory scales relative to the weighing scales, and means are configured for indicating filled weighing scales, and for discharging a filled weighing scale once the empty memory scale is situated below the filled weighing scale.

According to a particularly preferred embodiment whereby a further enhanced productivity is obtained with a given number of weighing scales and memory scales, there is provided underneath the memory scales at least two mutually separate collection means, said collection means each being configured with a view to collecting material batches from two or more memory scales.

This can be obtained in a simple manner in that the collection means comprise a funnel that extends underneath the memory scales, and wherein said funnel is provided with one or more walls that divide (s) the funnel into two or more separate chutes.

In this context it is particularly advantageously stationarily arranged underneath the memory scales, and that the weighing machine has a movement mechanism that is configured with a view to displacing the memory scales relative to the funnel whereby each of the memory scales is moved sequentially past each of the separate chutes in the funnel.

According to a further preferred embodiment of the invention, means are configured for emptying the weighing scales directly into the collection means, and means for

storing and calculating data concerning the weight and allocation of the individual material batches in the weighing scales as well as the memory scales with a view to selecting and emptying of the weighing scales and memory scales that contain material batches that combine to have a total weight that is close to a predetermined, desired total weight. Viz, a further productivity increase is hereby obtained due to an increased number of combination options.

The invention will now be subject to further description with reference to the drawing, wherein: Figure 1 is an explanatory sketch showing the construction of a weighing machine according to the invention; Figure 2 is an explanatory sketch showing a part of the construction of a weighing machine according to the invention as shown in Figure 1, seen in an inclined view from above; Figure 3 is an explanatory sketch showing a part of a weighing machine according to the invention, seen in an inclined view from above.

Thus, Figure 1 shows the principles underlying an embodiment of a weighing machine 1 according to the present invention.

The weighing machine is constructed symmetrically about a center line A and at the top it comprises distribution cone 2 mounted on the frame of the weighing machine 1 via a drive mechanism 3 that is in a commonly known manner

constructed in such a way that bulk products supplied to the top face of the distribution cone 2 are transported from the cone center and radially outwards towards a number of vibration grooves 4.

Only two such vibration grooves 4 are shown in Figure 1, but often a plurality of such vibration grooves 4 are used that are arranged around the distribution cone 2 and extend radially outwards from the distribution cone 2.

The vibration grooves 4 are each provided with a vibrator device 5 that causes the products transported from the distribution cone 2 to the vibration grooves 4 to be transported further outwards, but due to each of the vibration grooves 4 having each their vibrator device 5, the product flow can be controlled within the individual vibration grooves relative to each other.

Now, opposite each of the vibration grooves 4 a collection vessel 6 is arranged that is filled with products via the vibration grooves 4 and that each has its respective opening flap 7 which is openable such that a batch of products collected in the collection vessel can be transferred to a weighing scale 8 which is solidly mounted on the frame of the weighing machine 1.

In a commonly known manner, each of the weighing scales 8 is provided with means for weighing the batch located in the weighing scale 8 and for transmitting signal concerning ia the weight of the batch to a central calculator unit, said calculator unit being configured for performing combinational calculations with a view to identifying those scales that combine to contain a number of products that corresponds to a desired total amount.

The disclosed weighing means and the calculator unit as

such are not shown in the drawings, said units being of known type and the present explanation enabling the person skilled in the art to realize convenient embodiments thereof.

Once the calculator unit has carried out said calculations, it is configured for emitting a signal with a view to emptying the selected weighing scales 8, and for this purpose opening flaps 10,11 are arranged on each of the weighing scales, each of said opening flaps 10,11 being actuatable by the calculator unit.

In accordance with the invention, a number of memory scales 13 are configured below the memory scales. Such memory scales 13 are mounted on a carousel 14 that is able to rotate about the axis of symmetry A by means of a motor 15 that drives the memory scales around at a substantially constant peripheral velocity.

The weighing scales 8 being stationarily arranged on the frame of the weighing machine 1, and the memory scales 13 being rotatably arranged below the weighing scales 8, it is obvious that each of the weighing scales can be emptied by means of the opening flap 11 in any of the memory scales 13. Alternatively each of the weighing scales 8 can be emptied directly into the assembly funnel 12 that can be arranged underneath the entire arrangement of weighing scales 8 and memory scales 13.

Like the weighing scales 8, each of the memory scales 13 has a respective opening flap 16 that is openable whereby the product batch contained in the weighing scale can be discharged into the collection funnel 12. The calculator unit actuates the opening flaps 16 on the memory scales

13 to open when a number of actuators 19 are arranged that are secured relative to the frame of the weighing machine 1 and that can be actuated to exert a pressure on a latch 20 on the opening flap 16 of the memory scale 13 when the memory scale 13 passes the actuator 19.

In this manner the calculator unit can be configured to contain data concerning the contents of the production batches of the weighing scales 8 as well as each of the memory scales 13, and thus the calculator unit is able to perform combination calculations including all of these product batches, following which the calculator unit emits a signal to the effect that the weighing scales 8 and/or memory scales 13 that combine to contain product batches that give a total desired amount are emptied.

According to an alternative embodiment the opening flaps 10 on the weighing scales 8 can be omitted with the ensuing result that the weighing scales can be emptied into the memory scales 13 only. Hereby the number of possible combinations is reduced, but a weighing machine still results that has a relatively high productivity and a simple construction.

Now Figure 2 illustrates the funnel 12 shown in Figure 1 and the carousel 14 that can, by means of the motor 15, be rotated in the direction of the arrow about the center axis A of the weighing machine. Here the memory scales are formed by an annular container 17 that is divided into segments via a number of partition walls 18.

Figure 3 illustrates an advantageous embodiment of a collection funnel 12 for a weighing machine according to the invention. As will appear the funnel is, by means of partition walls 21, divided into four sectional funnels

12a, 12b, 12c, 12d that are each able to receive and collect product batches from the not shown memory scales and weighing scales, if any, that are located above the funnel 12 in the same manner as shown in Figure 1.

Hereby it is enabled by simple means that any of the rotating memory scales can be emptied into any of the sectional funnels 12a, 12b, 12c, 12d, which means that in principle several product batches can be discharged simultaneously even if such product batches are not to be constituents of the same combination of products.