CZ20013954A3 - Continuous band centering device, in particular for blister pack producing machine - Google Patents

Abstract

A device for centering a continuous band (2) driven through a series of working stations (7, 8) in a movement direction (D) includes at least one pair of rollers (12) rotatably carried with vertical axes, at the ends of arms (15). The arms (15) are pivoted along corresponding vertical axes on both sides of the band (2) symmetrically with respect to a longitudinal middle axis (A). The arms (15) are equipped with levers (23) for driving the arms (15) into symmetrical oscillation by limited angles. The arms (15) are subjected to the action of springs (22) which keep the rollers (12) touching the opposite sides of the band (2), so as to center the band (2) with respect to the movement direction (D).

Description

The invention relates to the handling of belts, for example belts, used in blister packaging machines.

In particular, the invention relates to a centering device for centering a continuous strip in which blisters are formed.

BACKGROUND OF THE INVENTION

Blister packaging machines have been developed to form blisters in a continuous web made of a thermoformable material, whereupon the blisters formed are filled with respective products.

The blister strip, the blisters of which are filled with the respective products, is then covered with a cover strip which is welded to it and then cut to obtain individual blister packs.

The web of thermoformable material, which is unwound from the spool, moves in a horizontal plane and in a horizontal direction and passes through a preheating station and then a forming station, where the respective blisters are formed by suitable means.

strip from a heat centered state in the forming area

It is essential that the longitudinal axis of the moldable material be maintained relative to the direction of travel of the web when the web is a blistering station.

Lateral displacement of the web relative to its direction of travel causes a defective placement of the blisters during the heat treatment operation of the web, which may present problems with the blistering of the respective articles since the filling means is usually centered relative to the longitudinal axis of the web.

Lateral displacement of the belt may cause a tensile force acting on it, or even slight damage to the belt, for example a not entirely constant thickness or width of the belt.

In order to prevent any lateral displacement of the belt, the blister packaging machines are provided with suitable guiding means on which the passing belt is supported and which keep the belt centered before and behind the blistering means.

The distance between the guiding means is manually adjustable to allow a change in their operation when a belt of a different size and size is used.

However, this change in the size and dimensions of the belt requires very demanding and expensive manual interventions, and very often additional adjustments are required to compensate for manufacturing tolerances of the belt.

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DD-A-47 845 discloses a continuous belt centering apparatus comprising a pair of pickup rollers disposed on both sides of a belt to be centered. The pair of rollers is supported by a y-shaped frame articulated at a central point, the springs acting on the frame.

The frame is also provided with a support roller on which the belt runs. The deviations of the belt from the correct track cause the frame to swivel, so that the support roller is oriented to bring the belt back to its correct track. It also compresses the springs, which react in such a way that they bring the belt back to its normal state.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the aforementioned problems by providing a device which automatically maintains a constant centering of the continuous belt relative to the direction of belt travel, and is particularly intended for use in machines equipped with workstations through which the belt is to pass. provided with blisters, particularly in blister packaging machines.

It is a further object of the present invention to provide a universal device, i.e. a device which will automatically center the continuous belt independently of the size and dimensions of the belt as well as the type of machine to which the device will be applied.

It is yet another object of the present invention to provide a centering device having a construction of >

Simple, functional and easy to use with known blister packaging machines.

The above objects have been accomplished in accordance with the present invention by providing a centering device for centering a continuous belt, wherein the continuous belt is guided by at least one workstation in the direction of movement, the apparatus comprising:

at least one pair of rollers rotatably supported on vertical axes at the ends of the arms, said arms rotatable about respective vertical axes on both sides of said strip symmetrically with respect to the longitudinal centerline, means for engaging said arms, said means for engaging causing an angularly limited symmetrical swing of said arms, said means for engaging said arms comprising respective levers, a first lever and a second lever projecting from said arms and having respective free ends, said levers engaging said free ends, resilient means acting on said arms to keep said rollers in contact with opposite sides of said belt for centering said belt with respect to said direction of movement, said levers engaging with each other simply by a pin extending vertically from said first lever and engaging a corresponding slot formed in said second lever.

Each of said arms is pivotable on a respective spindle, said resilient means each comprising a respective torsion spring, one end of which is attached to the upper side of said spindle, while the other end of said resilient means is attached to a respective support sleeve which extends axially said spindle.

Said sleeves are rotatable relative to the respective spindles by a predetermined angle for adjusting the elastic reaction force of said torsion springs.

The apparatus of the present invention further comprises sprung balls coaxially aligned with each of said sleeves for resiliently engaging a plurality of recesses formed in the flattening of said sleeve, said flattening being maintained in contact with said ring such that the angular position of said sleeves is fixed.

Each of said rollers comprises a pair of rollers rotatably mounted on a respective pair of coaxial axes so as to contact corresponding parts of said strip of thermoformable material unwound from the spool in said direction of movement.

Said rollers are provided with a groove in which said strip is guided, said groove being located in a horizontal plane in which said strip moves in a direction.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of examples of specific embodiments thereof, the description of which will be given with reference to the accompanying drawings, in which:

© ···· ·· · 9 · · • © ♦ © • · · · · · · · · · ⁹ • © © * · · · Fig. 1 is a schematic side elevational view of a machine for producing blister packs, equipped a proposed centering device for centering a continuous belt according to the invention;

Fig. 2 is a vertical sectional view of a proposed centering device according to the present invention; and Fig. 3 shows a corresponding plan view of the proposed centering device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the above drawings, reference numeral 1 denotes a blister-forming machine which generates blisters in a continuous web 2 made of a thermoformable material and subsequently fills the blisters formed with the respective products.

The continuous web 2 of thermoformable material is unwound from a spool 3 which rotates about the horizontal axis 6, being driven in the horizontal plane by the transfer rollers 5 and it.

During its movement in the horizontal plane in the horizontal direction D, the continuous strip 2 passes through the preheating station 7 and then the blistering station 8.

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At the outlet of the blistering station 8, the continuous strip 2 comes into contact with a guide 9 which assists in reversing the continuous strip 2 so that the open blisters are turned upward at a subsequent filling station, not shown in the figures.

The centering devices 10 and 11 for centering the continuous strip 2j, in particular its central longitudinal axis A relative to the horizontal direction D of the continuous strip movement, are respectively positioned in the forward direction before the preheating station 7 and after the blistering station 8.

The centering device 10, located downstream of the preheating station 11, comprises a pair of rollers 12 (see FIG. 2) which are mounted at the ends of the arms 15 on respective pins 13 having vertical axes.

The pair of rollers 12 can be rotated by insertion of rolling bearings 14.

The rollers 12 of the centering device 10 shown in FIG. 2 comprise a pair of rollers 12a and 12b that rotate on respective pairs of coaxial axes 13a and 13b so that they engage, as will be explained in more detail below, with the corresponding parts 2a, 2b of the continuous a strip 2 of thermoformable material which is unwound from the spool 3 (see FIG. 2).

The part 2a of the continuous strip 2 extends in the horizontal plane of the preheating station 7 and the blistering station 63 in the horizontal direction D.

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The arms 15 of the rollers 12 are rotatable by means 17 by means of the spindles of the axis.

The support means 17 are fixed by machines on opposite sides symmetrically to the central longitudinal axis A.

More specifically, each spindle 16 is rotatably mounted within the sleeve 19 by rolling bearings 18.

In its central part, the sleeve 19 forms an annular flattening 19a, the wider part of which is turned upward.

The helical torsion spring 22 is fixed at one end to the sleeve 19 and at the other end to the upper side of the spindle 16 protruding from the sleeve 19, i. to ring 21.

The arms 15j are provided with square levers 23 which engage with each other at their free ends (see Fig. 3) by means of a pin 24 extending vertically from the first lever 23 and fitting into a corresponding slot 25 provided in the second lever 23.

However, the two levers 23 may be connected together in a different manner, for example by means of toothed sections and the like.

The interconnected levers 23 have the task of driving the arms 15, which are subjected to the elastic reaction force of the spring 22, into angularly limited rotation and symmetrically to keep the rollers 12 in contact with opposite sides of the continuous belt 2 in order to

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9 999 • · ······· * centering this continuous strip 2 with respect to its horizontal movement D.

The resilient reaction force of the spring 22 may be appropriately adjusted by varying the angular position of the sleeve 19 with respect to the spindle 16 by rotating the sleeve 19 by a predetermined angle.

The attained position is maintained in a stable state by means of sprung balls 26 arranged in diagonally opposite positions in the corresponding seats formed in the ring 27, which is attached to the cover 28 of the support means 17.

The spring-loaded balls 26 resiliently fit into a system of recesses 29 formed in the annular flattening 19a of the sleeve 19 and arranged around the circumference.

The sleeve 19 is held in the axial direction by an annular nut 30 that contacts the upper surface of the ring 27.

As a result, these rollers 12, which act on opposite sides of the continuous belt 2: and are supported by the swinging arms 15, by being biased by the elastic reaction force of the springs 22, thus automatically maintain the central longitudinal axis A of the continuous belt 2 in to the horizontal direction D of the movement, as can be clearly seen in the illustration of FIG. 3.

If the size of the continuous web 2 of thermoformable material is changed, the device will automatically ···

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9 9 99 · · · 99 · adjusts the centering without having to adjust it manually.

The swinging arms 15 can swing at limited angles about the axes of the respective spindles 16, so as to keep the rollers 12 in contact with the sides of the continuous belt g as shown in Figure 3, where the dashed line 20 denotes a wider belt and the position occupied by the rollers 12 as a result of the swinging of the swinging arms 15.

It should be emphasized that the automatic centering is guaranteed due to the fact that the swinging arms 15, which support the rollers 12, swing symmetrically by the same angle due to their interconnection achieved by the angular levers 23.

The second centering device 11, which is functionally analogous to the just described centering device 10, is located downstream of the blister forming station 8, considering the horizontal direction D of movement.

The rollers 12 of the second centering device 11 are each provided with a groove 31 in which the continuous belt 2 is guided (see FIG. 1).

The groove 31, located substantially in the horizontal plane in which the continuous belt 2 moves, prevents the continuous belt 2 from being lifted during its movement in the horizontal direction D.

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Thus, the device according to the invention solves the problem of automatic centering of the continuous web 2 with respect to its movement in the horizontal direction D, especially in blister packaging machines.

This makes it possible to change the size of the continuous belt without manual adjustment, which results in higher productivity while eliminating the demanding and costly manual work.

It should also be pointed out that variations in the width of the continuous belt 2 are automatically registered by the proposed device, effectively counteracting the forces acting on the continuous belt 2 that tend to displace the continuous belt 2 relative to the horizontal direction D of its movement.

A further advantage of the proposed centering device according to the invention is that it has a very simple construction, excellent function and easy applicability for the known blister packaging machines.

The proposed device according to the invention has been described above with reference to its application in blister packaging machines. However, this device can also be advantageously used in all cases where it is necessary to center the continuous belt passing through several workpieces, with regard to its direction of movement.

It is to be understood that the foregoing description relates to purely limitless exemplary embodiments, and various design modifications may be made within the scope of the present invention as described above.

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Claims (3)

A centering device for centering a continuous belt, the continuous belt being guided by at least one work station (7, 8) in the direction of travel (D), the device comprising: at least one pair of rollers (12) rotatably supported on vertical axes at the ends of the arms (15), said arms (15) rotatable about respective vertical axes on both sides of said strip (2) symmetrically with respect to the longitudinal centerline (A) means (23) for engaging said arms (15), said engaging means (23) causing an angularly limited symmetrical swing of said arms (15), said means (23) for engaging said arms (15) comprising respective levers, a first lever and a second lever projecting from said arms (15) and having respective free ends, said levers being brought into engagement with said free ends, resilient means (22) acting on said arms (15) for maintaining said rollers (12) in contact with opposite sides of said strip (2) for centering said strip (2) relative to said a movement direction (D), characterized in that said levers (23) engage with one another by means of a pin (24) extending vertically from said first lever (23) and engaging a corresponding slot (25) formed in said second lever (24); 23). ······················ Device according to claim 1, characterized in that each of said arms (15) is pivotable on a respective spindle (16), said resilient means (22) each comprising a respective torsion spring, one end of which is fixed to the upper side said spindle (16), while the other end of said resilient means (22) is attached to the respective support sleeves (19), Which in axial direction going through listed spindle (16). 3. Equipment according to claim 2, v y z n and whatever c í s e by listed sleeves (19) are rotating with respect to the respective spindles (16) a predetermined angle for adjusting the elastic reaction force of said torsion springs (22). 4. Equipment according to claim 3, v y z n and watching with that contains suspended marbles (26), embedded in the ring (27) coaxial with each of said sleeves (19) for flexible shot with set recesses (29) formed in the flattening (19a) of said sleeve (19), said flattening (19a) being contacting said ring (27), so the angular position said sleeves (19) is fixed. 5. Equipment according to claim 1, characterized by that everyone of the above the rollers (12) comprises a pair of cylinders (12a, 12b), rotatably saved on the appropriate a pair of coaxial axes (13a, 13b), so touching corresponding parts (2a, 2b) of said strip (2) 99 99 999 99 9 9 9 9 9 9 9 9,999 99 9 9 9 9 99 9 99 99 9999 of thermoformable material unwound from the spool (3) in said movement direction (D). Device according to claim 1, characterized in that said rollers (12) are provided with a groove (31) in which said strip (2) is guided, said groove (31) being located in a horizontal plane in which said the belt (2) moves in the direction (D).