Incoherent Product Volumetric Batching Device For High Speed Packaging Machines

Abstract

An improved device for dispensing volumetric batches of incoherent products, particularly for high speed packaging machines, comprising a dispensing drum with horizontal axis of rotation, having peripherally distributed batching recesses, a product feed hopper associated with the dispensing drum, means for the entrainment of the packaging band from which the envelopes for the product batches are formed and which is maintained in contact with the surface of the dispensing drum without slipping on it.

Description

BACKGROUND OF THE INVENTION

This invention relates to an improved dispensing device, which measures the dispensed quantities by volume and is particularly suitable for dispensing powders, granular products, tea, camomile and similar incoherent fluent products in high speed packaging machines. Conventional volumetric batching employ rotating batchers comprising essentially a drum-like batching member with a horizontal axis of rotation and radial batching recesses.

In these conventional devices the drum receives the product directly or indirectly from a feed hopper and during rotation the drum pours the product on to packaging material underneath, for example comprising a continuous paper band travelling horizontally.

Known embodiments of these batchers can only work at low speeds because they suffer the combined effects which the centrifugal force and gravity have on the product batches which leave the batcher. In face these forces are prportional to the speed of rotation of the batcher, and increase the speed of the product as it falls on to the packaging band and create kinetic conditions which are liable to distort the shape of the measuring quantities of product especially at the moment of impact of the product on the packaging band.

On the other hand, as verified in the case of other embodiments, the presence of a fixed leveller or scraper extending to the lower horizontal zone of the drum tangential with wrapping band doe not permit an efficient operation of the batcher at high speeds, because the relative movement between the drum and the fixed leveller enables the product to infiltrate between the rotating and fixed surfaces causing wear and tear, damage of the product itself and sometimes complete obstruction of the rotating parts of the device. These disadvantages are commonly met in conventional embodiments of rotating volumetric batchers, and their gravity is more seriously felt the faster the batcher works and the more the product presents characteristics of easy penetration and/or abrasion.

SUMMARY OF THE INVENTION

The object of this invention is that of providing an improved volumetric dispensing device with a rotating batcher which is free from the foregoing speed limiting disadvantages, able that is to neutralize the secondary effects due to the rotation of the batcher and the falling of the product, and to prevent the possibility of wear and destruction of the mechanical parts engaged in the batching operation.

A further object is that of providing the product batches with a predetermined shape which is conserved even after the product has been transferred on to the packaging material. According to the present invention there is provided a device for dispensing volumetric batches of incoherent material comprising a horizontally arranged material dispensing cylinder which is rotatable about its horizontal axis and is provided with a plurality of radially outwardly open pockets, a hopper for the material positioned at the top of the dispensing cylinder and adapted to feed by gravity incoherent material into the pockets as the cylinder rotates, a roller idly supported adjacent and downstream of said hopper and adapted to deviate a strip of packaging material around the dispensing cylinder in the direction of rotation of the latter so as to partially wrap said cylinder and means for driving the strip of packaging material including a pair of counterrotating entraining rollers through which the strip passes and provided with complementary recesses, wherein according to the improvement said entraining rollers have their rotation axes lying in a vertical plane and their contact line lying in a horizontal plane tangential to the lower point of the dispensing cylinder so that the strip defines a horizontal run extending from the dispensing cylinder to said entraining rollers for receiving the volumetric batches of incoherent material deposited thereon from said pockets as the dispensing cylinder rotates, said volumetric batches during passing said entraining rollers being accomodated in said complementary recesses.

In consequence the transfer of the batches from the batching recesses to the band of wrapping material is effected without fall and without relative slip movement at the zone in which the cylindrical surface of the batching member separates from the band which continues rectilinearly entrained by the entrain-ment means.

BRIEF DESCRIPTION OF THE DRAWING

Further characteristics and advantages of the invention will become more evident from the detailed description of a preferred but not limiting embodiment of an improved volumetric dispensing device, with reference to the accompanying drawing in which:

FIG. 1 is a diagrammatic elevational view of the dispensing device;

FIG. 2 is a diagrammatic perspective view of the dispensing device and the relative members for the transmission of motion.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the foregoing figures, the improved volumetric batching device according to the invention comprises essentially a hopper 1, a cylindrical batching drum or dispensing cylinder 2 rotating about a horizontal axis and situated at the bottom of the hopper, a flexible band or strip 3 which winds around the cylindrical surface of the batching member through an arc which extends substantially from the hopper to the lower horizontal tangent line 4. The band 3 forms the material intended to wrap the product batches and is drawn from a feed spool 7 of controlled tension, comprising essentially a shaft 8 with associated braking means 9 of conventional type. Adjacent and immediately downstream of the hopper 1 an idle roller 10 is arranged which deviates the band 3 around the dispensing cylinder 2 in the anticlockwise direction so as to partially wrap said cylinder through an arc of approximately 180.degree. extending substantially from the hopper 1 to the lowermost point of the cylinder 2. For the advancement of the band 3 a pair of entraining rollers 5, 6 is provided arranged downstream from the cylinder 2 and pressed together to form a nip. Roller 6 presses on the lower face of the band 3, while roller 5 presses on the upper face through a second band 20. The rollers 5,6 are counterrotating in the directions shown by the arrows in FIG. 1 and their rotation axes lie in a vertical plane.

The dispensing cylinder 2 comprises peripheral recesses or pockets 11 (FIG. 2) suitable to be totally filled with product and to be scraped by a small scraper 12, advantageously acting at the summit of the cylinder, i.e., in the zone in which the centrifugal force due to the rotation of the dispensing cylinder acts in exactly the opposite direction to that of the force of gravity.

From the figures it will be noted that the idle roller 10 is placed in the immediate vicinity of the scraper 12. This arrangement causes the batches of product to pass immediately under the band because of the anticlockwise direction of rotation of the batching member, by which means uncontrolled product losses and possible jamming are avoided, as there is no relative movement between the parts in rotation. In fact since the rollers 5,6 have a peripheral speed equal to that of the dispensing cylinder 2 after the batches contained in the recesses have been covered by the wrapping band 3, the cylinder 2 and the band 3 maintain their reciprocal position until the tangent line 4, in which the band 3 separates horizontally from the cylinder to define a run passing between the entraining rollers 5, 6.

A chain 13 and two toothed chair wheels 14, 15 (FIG. 2) link the shaft of the cylinder 2 to the shaft of the roller 5 and the roller 6 is driven through gears 16, 17. It will be understood that the whole rotary system of the device is connected in conventional not shown manner to a source of rotary motion. It should be noted that the rollers 5, 6 which drive the flexible band 3 also generate a tension in this band which thus applies a radial compressive force on the dispensing cylinder 2, which eliminates the use of any external means for compressing the band against the cylinder and which would inevitably create friction.

The entraining rollers 5, 6, are formed with peripheral pockets or recesses 18 which are complementary each other and positioned to align as the rollers 5,6 rotate. A second band or strip 30 of wrapping material drawn from a spool 19 with relative braking means 21, winds around the entraining roller 5 and meets the horizontal run of the band 3 in order to cover the heaps 22 of product deposited on it. It will be seen that the pockets 18 in the driving rollers 5 and 6 are designed to accomodate the heaps 22 of product located between the bands 3 and 20 as the bands and the product pass through the nip between the rollers.

The important characteristic of the thus improved device is derived from the manner in which the batches pass from the dispensing cylinder, to the band 3, i.e., without falling or running. In fact the heaps 22 conserve the shape of the batching recesses 11 and remain spaced apart on the band 3 thus permitting an exact sealing of the upper and lower packaging bands and an exact correlation between the positioning of the heaps 22 on the band 3 and the pockets 18 provided on the rollers 5,6 used to join the upper and lower packaging bands together.

Claims

I claim:

1. Device for dispensing volumetric batches of incoherent material comprising a horizontally arranged material dispensing cylinder which is rotatable about its horizontal axis and is provided with a plurality of radially outwardly open pockets, a hopper for the material positioned at the top of the dispensing cylinder and adapted to feed by gravity incoherent material into the pockets as the cylinder rotates, a roller idly supported adjacent and downstream of said hopper and adapted to deviate a strip of packaging material around the dispensing cylinder in the direction of rotation of the latter so as to partially wrap said cylinder, and means for driving the strip of packaging material including a pair of counterrotating entraining rollers through which the strip passes and provided with complementary recesses, wherein according to the improvement said entraining rollers have their rotation axes lying in a vertical plane and their contact line lying in a horizontal plane tangential to the lower point of the dispensing cylinder so that the strip defines a horizontal run extending from the dispensing cylinder to said entraining rollers for receiving the volumetric batches of incoherent material deposited thereon from said pockets as the dispensing cylinder rotates, said volumetric batches during passing said entraining rollers being accomodated in said complementary recesses.

2. Device as claimed in claim 1 wherein means are provided for guiding a cover strip of packaging material through said entraining rollers to cover the volumetric batches of material deposited on said horizontal run.