Device for compressing empty containers

Abstract

Device (10) for compressing empty containers, in particular beverage bottles or cans made of plastic, for example PET, or tinplate, comprising: - two rotary rollers (12a, 12b) which can be driven in opposite directions to compress containers fed between each other; wherein: - the respective axes of rotation (L12a, L12b) of the rotary drums (12a, 12b) are aligned parallel to each other and spaced apart by an axis distance (K); - the rotary rollers (12a, 12b) each comprise a circular cylindrical roller body (14) and a plurality of disc-shaped tooth groups (16) spaced apart from each other in the axial direction of the roller body (14); - each of the tooth groups (16) comprises an equal number of circumferentially spaced teeth (18), each extending radially from a tooth base (18a) to a tip (18b), wherein an inner radius (R1) of the rotating drum (12a, 12b) is defined at the tooth base (18a) and an outer radius (R2) of the rotating drum (12a, 12b) is defined at the tip (18b); - the respective tooth groups (16) of the two rotating rollers (12a, 12b) are axially offset from each other in such a way that they engage between each other; - the inner radius (R1) and the outer radius (R2) together are larger than the center-to-center distance (K), but the center-to-center distance (K) is larger than twice the inner radius (R1); and - the width (c) of each tooth (18) at the tooth base (18a) is less than or equal to half the distance (b) between adjacent teeth (18) within a group of teeth (16) at the tooth base (18a).

Description

[0001] The present invention relates to a device for compressing empty containers, in particular beverage bottles or cans made of plastic, for example PET or tinplate, comprising two rotating rollers which can be driven in opposite rotation in order to compress containers fed between one another.

[0002] Such generic devices are used in particular to compact empty containers from the food sector, such as beverage bottles, cans and other deformable containers, in order to simplify transport and / or recycling processes thereof.

[0003] For this purpose, so-called "crushers" have been used in particular, which compact the beverage containers in question using rotating rollers with various surface geometries. However, after a corresponding pressing process between the interacting rotating rollers, plastic bottles in particular generally expand again to a thickness of approximately 20 mm to 30 mm due to the so-called "memory effect." However, in such processes, the greatest possible compaction of the containers is desired, among other things, so that the collection containers of return machines for deposit bottles equipped with such devices need to be emptied as infrequently as possible and so that the compacted containers require as little space as possible for further transport.In any case, every emptying of such a reverse vending machine in retail represents a standstill and thus waiting times for customers of the corresponding store and requires the deployment of personnel to empty and restart the corresponding machine.

[0004] Furthermore, it is required that tinplate beverage cans are not broken down into several pieces during compaction processes in order not to complicate subsequent sorting processes.

[0005] Accordingly, the object of the present invention is to further develop a generic device for compressing empty containers in such a way that the highest possible degree of compaction of the corresponding containers is achieved and permanently ensured, while at the same time preventing the compacted containers from breaking into multiple pieces. Furthermore, the device according to the invention must be able to process both bottles, particularly PET bottles, and cans, and thus be usable in a combination or mixed operation.

[0006] To achieve this object and to eliminate the above-discussed disadvantages of the known prior art, it is proposed according to the invention that in a generic device with two rotating rollers, which can be driven in opposite rotation to compress containers fed between one another, the respective axes of rotation of the rotating rollers are aligned parallel to one another and spaced apart by an axial distance, the rotating rollers each comprise a circular-cylindrical roller body and a plurality of disc-shaped tooth groups spaced apart from one another in the axial direction of the roller body, each of the tooth groups comprises an equal number of teeth equally spaced in the circumferential direction, which each run radially from a tooth base to a tip, wherein an inner radius of the rotating roller is defined at the tooth base and an outer radius of the rotating roller is defined at the tip,the respective tooth groups of the two rotating rollers are axially offset from one another in such a way that they mesh between one another, the inner radius and the outer radius together are greater than the axial distance, but the axial distance is greater than twice the inner radius, and the width of each tooth at the tooth base is less than or equal to half the distance between adjacent teeth within a tooth group at the tooth base.

[0007] This means that the respective tooth base of each of the teeth is already located on a disc that protrudes from the cylinder base and thus from the roller body, enabling the corresponding teeth to mesh between adjacent groups of teeth on the respective opposite rotating roller. Accordingly, the groups of teeth of the device according to the invention mesh with each other in such a way that, on the one hand, the beverage containers to be compacted are perforated as often as possible, but neither a longitudinal cut nor a cross-section is made completely, in order to maintain the integrity of the respective containers.

[0008] Accordingly, the multitude of incisions and deformations created by the teeth compress a corresponding container between the rotating rollers to form a stable, wave-shaped surface, and it has been shown that the increased and sustainable compaction achieved in this way enables collection containers of reverse vending machines to accommodate an approximately 30% higher number of containers, thereby achieving the savings mentioned above in the operation of such machines and the subsequent transport of the compacted containers.

[0009] The corresponding deformation of the containers is achieved in particular by the teeth of the rotating rollers penetrating both sides of the container walls, partially deforming the cut walls in this area. The two walls then interlock, preventing the compacted containers from expanding again after the compression process. Accordingly, the compacted containers remain flat thanks to the interlocked walls, preventing a memory effect, such as would typically occur with PET containers.

[0010] In principle, it is possible to construct the teeth symmetrically with respect to the radial direction of the corresponding rotating roller, although alternative designs would also be conceivable in which the teeth are inclined or curved forward by a certain amount in the direction of rotation of the corresponding rotating roller.

[0011] Although the specific dimensions of the rotating rollers and their teeth depend to some extent on the type of container they are intended to compact, it can be seen that for commonly used bottles and cans the width of the teeth at the tooth base can be, for example, between 3 mm and 10 mm, preferably about 5 mm, and / or that the distance between adjacent teeth within a tooth group at the tooth base can be between 6 mm and 20 mm, preferably about 10 mm.

[0012] Similarly, the center distance may be between 50 mm and 100 mm, in particular between 60 mm and 80 mm, further in particular about 69 mm, while again the outer radius of the rotating rollers may be between 30 mm and 50 mm, in particular about 41 mm.

[0013] While the number of teeth per tooth group of the two rotating rollers is not initially fixed and can also be made dependent on the corresponding radii of the rotating rollers, it can be provided, for example, that the distance between the tips of adjacent teeth within a tooth group can be between 10 mm and 30 mm, preferably about 18 mm.

[0014] Furthermore, in the device according to the invention, the difference between the axial distance and twice the inner radius can be between 1 mm and 6 mm, preferably approximately 3 mm. This difference describes the dimension that does not overlap during rotation of the rotating rollers, so that the containers to be compacted are not cut through in this area. If the wall thicknesses of the containers to be compacted are known, this difference should ideally be approximately six times the wall thicknesses to ensure that no undesired comminution occurs, even in the area of ​​the base and bottle neck of the corresponding containers.However, since it cannot be assumed in practice that only containers with a uniform, standardized wall thickness will be compactable, it has been shown that the range of values ​​just cited for possible differences covers a wide spectrum of wall thicknesses encountered in practice. The example value of 3 mm would correspond exactly to a wall thickness of 0.5 mm, assuming six times the value. Corresponding wall thicknesses are often used for beverage bottles, so at the same time, sufficient leeway would remain for upward or downward deviations in the wall thickness.

[0015] Furthermore, the radial height of each tooth may be between twice and four times the difference between the axial distance and twice the inner radius, preferably about 2.7 times, while alternatively or additionally the distance between adjacent groups of teeth on the two rotating rollers in the axial direction of the rotating rollers may be between 0.05 mm and 0.15 mm.

[0016] Further features and advantages of the present invention will become more apparent from the following description of an embodiment thereof, when considered together with the accompanying figures. These show in detail: Fig. 1 is an oblique sectional view of a device according to the invention; Fig. 2 the device from Fig. 1 in a side sectional view of the rotating rollers of the device; and Fig. 3 an isolated representation of the rotating rollers to clarify their dimensions.

[0017] Fig. Figure 1 initially shows, in an oblique side view, a partial view of a device 10 according to the invention, for example, for a return machine for deposit bottles, for compressing corresponding empty containers. The basic functioning of such machines 100 is known, so it will not be discussed in detail here. It can only be seen that containers to be compressed are fed via a feed path 102 in a funnel-shaped manner to the device 10 for compression, compaction, or compaction thereof. These containers are then ejected at an outlet 104 and can be transferred, for example, to a collecting container.The feed paddle used in the feed path 102 and in the present case designed with two wings is to be understood as a component of the device 10 and is coupled in particular via a chain drive to the rotating rollers 12 and 12b described below and serves to press the containers to be processed, such as cans and bottles, against the rotating rollers 12a, 12b and thereby assist their feed.

[0018] The device 10 comprises two rotating rollers 12a and 12b, which can be driven in counter-rotation by a drive system not shown here, wherein the sectional view from Fig. 2 is chosen in such a way that the viewing direction is along the Fig. 1 schematically indicated axes of rotation L12a and L12b of the two rotating rollers 12a and 12b.

[0019] It can be seen that the respective rotational axes L12a and L12b are aligned parallel to each other and spaced apart by an axial distance, whereby for the following description of the geometric dimensions of the rotating rollers 12a and 12b, particular reference is also made to the Fig. 3, which shows them in an isolated view with corresponding markings. The aforementioned axial spacing is specifically designated by the letter K.

[0020] The two rotating rollers 12a and 12b are essentially identical to each other and each comprise a circular-cylindrical roller body 14 and a plurality of disc-shaped tooth groups 16 spaced apart in the axial direction of the corresponding roller body 12a, 12b, which are also identical to each other. The corresponding disc-shaped tooth groups 16 of the two rotating rollers 12a and 12b engage in corresponding spacings between adjacent tooth groups 16 of the respective other rotating roller 12b, 12a, by means of respective teeth 18 provided radially outwardly on the tooth groups 16.Here, each of the tooth groups 16 comprises an equal number of teeth 18 which are equally spaced in the circumferential direction and which each run radially outwards from a tooth base 18a on an annular disk 16a to a tip 18b, wherein an inner radius R1 is defined at the tooth base 18a and an outer radius R2 of the rotating rollers 12a, 12b is defined at the tips of the teeth 18 of a tooth group 16.

[0021] In order to enable the aforementioned meshing of the tooth groups 16 of the two rotating rollers 12a and 12b, the inner radius R1 and the outer radius R2 together must be greater than the axial distance K, but the axial distance K must be greater than twice the inner radius R1. This is particularly good in Fig. 3, in which the difference between the axial distance K and twice the inner radius R1 is denoted by a, which can be, for example, 3 mm. It is assumed here that the axial distance K is approximately 69 mm and the outer radius R2 of the two rotating rollers 12a and 12b is approximately 41 mm each.

[0022] Furthermore, the distance between adjacent teeth within a tooth group at the tooth base is designated b, which in the embodiment shown here is approximately 10 mm, and the width of the teeth at their respective tooth base is designated c and is approximately 5 mm here. Generally speaking, in this context, the difference between b and c defines the total length of an uncut area of ​​a compressed container above and below respective punctures. Accordingly, it should be approximately 50% of the distance between the tips of adjacent teeth, which in the Fig. 3 is designated by d and in the embodiment shown here is approximately 18 mm.

[0023] Furthermore, Fig. 3 where g denotes the overlap from tip to root diameter of the respective opposite rotating roller 12a or 12b, which is preferably about 1.5 times to 2 times a, while h denotes the total overlap and is preferably about 4.5 times a. Finally, in Fig. 3 the height of each tooth is denoted by i, which in the present case is about 2.7 times a.

[0024] The geometric relationships described above achieve the object of the invention of achieving maximum compaction of empty containers and cutting and deforming them in such a way that they are compacted into a stable, wave-shaped surface with minimal dimensions.

Claims

[1] Device (10) for compressing empty containers, in particular beverage bottles or cans made of plastic, for example PET, or tinplate, comprising: - two rotating rollers (12a, 12b) which can be driven in opposite rotation to press containers fed between each other together; wherein: - the respective axes of rotation (L12a, L12b) of the rotating rollers (12a, 12b) are aligned parallel to one another and spaced apart by an axial distance (K); - the rotating rollers (12a, 12b) each comprise a circular-cylindrical roller body (14) and a plurality of disc-shaped tooth groups (16) spaced apart from one another in the axial direction of the roller body (14); - each of the tooth groups (16) comprises an equal number of circumferentially equally spaced teeth (18), each of which runs radially from a tooth base (18a) to a tip (18b), wherein an inner radius (R1) of the rotating roller (12a, 12b) is defined at the tooth base (18a) and an outer radius (R2) of the rotating roller (12a, 12b) is defined at the tip (18b); - the respective groups of teeth (16) of the two rotating rollers (12a, 12b) are axially offset from one another in such a way that they engage between one another; - the inner radius (R1) and the outer radius (R2) together are greater than the axial distance (K), but the axial distance (K) is greater than twice the inner radius (R1); and - the width (c) of each tooth (18) at the tooth base (18a) is less than or equal to half the distance (b) between adjacent teeth (18) within a tooth group (16) at the tooth base (18a). [2] Device (10) according to claim 1, wherein the teeth (18) are each constructed symmetrically with respect to the radial direction. [3] Device (10) according to one of the preceding claims, wherein the width (c) of the teeth (18) at the tooth base (18a) is between 3 mm and 10 mm, preferably about 5 mm and / or the distance (b) between adjacent teeth (18) within a tooth group (16) at the tooth base (18a) is between 6 mm and 20 mm, preferably about 10 mm. [4] Device (10) according to one of the preceding claims, wherein the axial distance (K) is between 50 mm and 100 mm, in particular between 60 mm and 80 mm, further in particular about 69 mm. [5] Device (10) according to one of the preceding claims, wherein the outer radius (R2) of the rotating rollers (12a, 12b) is each between 30 mm and 50 mm, in particular approximately 41 mm. [6] Device (10) according to one of the preceding claims, wherein the distance (d) between the tips (18b) of adjacent teeth (18) within a group of teeth (16) is between 10 mm and 30 mm, preferably about 18 mm. [7] Device (10) according to one of the preceding claims, wherein the difference (a) between the axial distance (K) and twice the inner radius (R1) is between 1 mm and 6 mm, preferably about 3 mm. [8] Device (10) according to one of the preceding claims, wherein the radial height (i) of each tooth (16) is between twice and four times the difference (a) between the axial distance (K) and twice the inner radius (R1), preferably about 2.7 times. [9] Device (10) according to one of the preceding claims, wherein the distance between adjacent groups of teeth (16) on the two rotating rollers (12a, 12b) in the axial direction of the rotating rollers is between 0.05 mm and 0.15 mm.

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