Buffer storage unit

Abstract: Buffer storage unit for accumulating and releasing, in rows which are equidistant or have a programmed timing, products which arrive from a continuous advancement line and are arranged in non-equidistant rows, including a first conveyor belt (2) and a second conveyor belt (3) which are respectively actuated continuously and stepwise, and which have respective active portions (2a,3a) extending horizontally after one another. The belts are closed on themselves in a loop and are wound around respective sets of rollers, and the output roller (5a) of the first belt (2) and the input roller (7a) of the second belt (3) are mounted on a first slider (8) which is horizontally slidingly guided and which is associated with actuation elements which are controlled by sensors (16,17) which detect the presence of the products. The first one (16) of the sensors is arranged at the output of the active portion (2a) of the first belt (2), and the second one (17) is arranged at the output of the active portion (3a) of the second belt (3), so that upon the arrival of a product at the first sensor (17) the slider (8) is actuated in the direction opposite to the product advancement direction and so that upon the release of a product from the second belt (3) the slider (8) is actuated in the product advancement direction.

Description: The present invention relates to a buffer storage unit, in particular for accumulating and releasing, in rows which are equidistant or have a programmed timing, products which arrive from a continuous advancement line and are arranged in non-equidistant rows. Lines for packaging products such as chocolate bars, candy or the like are known, wherein the products are removed from their mold and placed on a conveyance line which extends continuously; said products are arranged in rows or groups of rows which are spaced from one another in a not strictly uniform manner (the term "rows" is used to indicate lines of products arranged perpendicular to the product advancement direction). Said rows must be transferred onto a second line which has a constant speed which is different from that of the first line; on said second line, the rows must have a strictly constant mutual distance so as to be able to effectively feed subsequent packaging machines. There are packaging machines (see EP-A-259 733) which are capable of changing their operating speeds according to the variations in the flow of the incoming rows, but said changes are rather difficult to perform, require a certain time to be performed and do not effectively solve the problem. The technical aim of the present invention is to obviate the above described disadvantages, i.e. to provide a buffer storage unit which can correctly feed automatic packaging lines provided with a plurality of row distributors to which packaging machines suitable for varying their speed are connected. Within the scope of this technical aim, an object of the present invention is to achieve said aim by means of a buffer storage unit having reduced dimensions, in that it is only slightly longer than a row accumulation region. Another object of the present invention is to achieve the above aim with a structure which is simple, relatively easy to execute in practice, safe in use and effective in operation as well as relatively modest in cost. This aim and these objects are all achieved by the present buffer storage unit as defined in the appended claims. Further peculiarities will become more apparent from the detailed description of a preferred but not exclusive embodiment of a buffer storage unit according to the present invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a partially cutout perspective view of a buffer storage unit for the accumulation and release of products in rows which are equidistant or have a programmed timing, according to the invention; figure 2 is a schematic side view of the buffer storage unit during the accumulation of a row; figure 3 is a schematic side view of the buffer storage unit during the release of a row. With particular reference to the above figures, the reference numeral 1 generally indicates the buffer storage unit for the accumulation of products which arrive from a first line L1 and which are distributed in not always equidistant rows, and for the release thereof onto a second line L2 with well-determined constant pitches or with a programmed timing. The buffer storage unit 1 comprises a fixed supporting structure which has not been illustrated in the figures in order to avoid uselessly encumbering the drawing; reference will be made to said structure in order to progressively indicate the components which must be connected thereto. The buffer storage unit 1 comprises a first conveyor belt 2 and a second conveyor belt 3 which are actuated, respectively, continuously in the direction A and stepwise in the direction B: the active portions 2a, 3a of the belts are horizontal and co-planar and are arranged one after the other. The belt 2 is wound around rollers 4a, 4b, 4c, 4d, 4e which are rotatably mounted transversely to the fixed supporting structure; the roller 4e is associated with a drive unit which is suitable for making said roller turn continuously in the direction of the arrow C; the belt 2 also winds around an output roller 5a of the active portion and around an input end roller 5b. Similarly, the belt 3 is wound around the rollers 6a, 6b, 6c, 6d, 6e, which are rotatably mounted transversely to the fixed supporting structure; the roller 6e is associated with a drive unit which is suitable for making it turn stepwise in the direction of the arrow D; the belt 3 also winds around an upper input roller 7a and an output end roller 7b. The rollers 5a and 7a are freely mounted side by side, so as to be substantially mutually tangent, on a first slider 8 which comprises two lateral sliding blocks 8a, 8b which are horizontally slidingly guided along two sides of the fixed supporting structure. The end rollers 5b and 7b are freely mounted side by side, so as to be substantially mutually tangent, on a second slider 9 which is in turn constituted by two sliding blocks (the first of which is indicated in figure 1 by the reference numeral 9a) which are also horizontally slidingly guided along two sides of the fixed supporting structure. The pairs of sliding blocks of the sliders 8, 9 are mutually connected by a pair of first traction elements such as chains or toothed belts (one of which is indicated by the reference numeral 10a) which are wound around respective drive and transmission gearwheels 11, 12: the gearwheels can rotate in opposite directions, indicated by the double arrow E, and are suitable for moving the sliders in opposite directions, indicated by the arrows F and G, and thereby an actuation of the slider 8 in one direction is matched by an equivalent actuation of the slider 9 in the opposite direction. The rollers 4 and 5 of the first belt and the rollers 6 and 7 of the second belt define, from the top downward, respective active conveyance portions 2a and 3a, return portions 2b and 3b, upper compensation portions 2c and 3c and lower compensation portions 2d and 3d. The length of the sum of the portions 2a (2b) and 2c (2d) remains substantially constant even during the movements of the sliders. The upper and lower portions of second traction elements such as two lateral chains or toothed belts 13, which are mutually connected by a plurality of transverse free rollers 14, extend respectively between the planes defined by 2a, 3a and by 2b, 3b and between the planes defined by 2c, 3c and 2d, 3d; each of the chains 13 is wound around four free gearwheels 15. The chains are fixed to the sliders 8 and 9, and related guides are provided on the two sides of the machine; the rollers 14 are movably supported along said guides and support the upper active portion of the conveyor belts 2a and 3a so that it does not bend under the weight of the products. Two product sensors 16, 17 are respectively arranged at the outputs of the active portions of the belts, i.e. the portion 2a associated with the slider 8, of the first belt, and at the output of the second belt, and are suitable for detecting the presence of the rows; said sensors control, by means of known actuation elements, the actuation of the first traction elements 10a, so that when the sensor 16 detects the arrival of a row, the slider is rapidly actuated in the direction F so that the row is transferred onto the active portion 3a. When the belt 3a moves by one step, the slider 8 is actuated in the direction G and follows the last stored row, maintaining the transfer front directly behind the last buffered row. In practice, when one row arrives at the end of the first belt, the second belt is rapidly moved under it with a simultaneous backward winding which avoids shocks to the product. Shortly after the input of the belt 2, and shortly upstream of the output of the belt 3, two sensors 18, 19 for sensing the presence of the slider 8 are respectively fixed to the framework of the machine and detect the excessive filling or excessive emptying of the buffer storage unit. It is not possible to act on the arrival rate of the products, but it is possible to act, to a certain extent, on the rate of removal of the products downstream of the machine by increasing or decreasing for a certain period of time the operating speed of a packaging machine. In relation to this, if the sensor 18 detects excessive filling, the operating speed of a machine arranged downstream is increased, by means of known actuation means connected to said sensor 18, until the operating conditions are resumed, whereas if the sensor 19 detects excessive emptying it is necessary to stop, again by means of known actuation means, the machine arranged downstream until a certain minimum number of rows has arrived on the buffer storage unit. At the output of the machine there is a flow of uniform rows even if the rows enter at a random rate. The filling or emptying condition of the buffer storage unit allows to control the speed of the packaging machines. It has thus been observed that the invention achieves the intended aim and objects. In practice, the materials employed, as well as the shapes and dimensions, may be any according to the requirements without thereby abandoning the protective scope of the following claims. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: Buffer storage unit, for accumulating and releasing, in rows which are equidistant or have a programmed timing, products which arrive from a continuous advancement line and are arranged in non-equidistant rows, comprising a first conveyor belt (2) and a second conveyor belt (3), said conveyor belts defining respective active portions (2a,3a) which extend, horizontally after one another, said conveyor belts being closed on themselves in a loop and being wound around respective sets of rollers (4,6), an output roller (5a) of the first belt (2) and an input roller (7a) of the second belt (3) being mounted on a first slider (8) which is horizontally slidingly guided and which is associated with actuation means which are controlled by sensors (16,17) which detect the presence of the products, the first one (16) of said sensors being arranged at the output of the active portion (2a) of the first belt (2), characterized in that said first (2) and second (3) conveyor belts are respectively actuated continuously and stepwise, in that the second sensor (17) is arranged at the output of the active portion (3a) of the second belt (3), in that upon the arrival of a product at the first sensor the slider is actuated in the direction opposite to the product advancement direction and in that upon the release of a product from the second belt the slider is actuated in the product advancement direction, a region for the accumulation of equally spaced products thus being defined between the advancement stroke limits of said slider. Buffer storage unit according to claim 1, characterized in that the two belts (2,3) have respective compensation portions (2c,2d,3c,3d) which extend at a level lower than the active portions (2a,3a) and the related end rollers (5b,7b) whereof are mounted on a second slider (9) which is horizontally slidingly guided in a parallel manner in the opposite direction and on a plane which lies below the plane of the first slider (8). Buffer storage unit according to claim 2, characterized in that said first (8) and second sliders (9) are connected to the upper and lower portions of a pair of lateral actuation chains (10a) which are wound around respective pairs of driving and transmission gearwheels (11,12). Buffer storage unit according to claim 2, characterized in that said belts (2,3) are wound around rollers, of which the output and input rollers of the first and second belts and the related end rollers are movable and the other rollers are fixed, said rollers defining, from the top downward, an active product conveyance portion (2a,3a), a return portion (2b,3b), an upper compensation portion (2c,3c) and a lower compensation portion (2d,3d), the sum of the length of the active portion of one of the belts and of one of the compensation portions being substantially constant. Buffer storage unit according to claim 2, characterized in that two lateral guides are arranged between the active conveyance portion and the return portion, a plurality of free rollers (14) for supporting the active portions (2a,3a) being guided horizontally along said guides, said rollers being associated by two related lateral chains (13) the ends whereof are fixed to said sliders (8,9).

Inventors: SCHEID MANFRED, SCHEID, MANFRED
Applicants: MOPA SRL, MOPA S.R.L.
Application year: 1991
Main classification: B65G47
IPC codes: B65G47, B65G21