Continuously Operating Rotational Bottle Filling Installation

The invention relates to a continuously operating rotational bottle filling device.

So called PET bottles (polyethyleneterephthalate), which have relatively thick-walled collars near their openings but have walls and bottoms that are thin, are being used to an ever increasing degree to contain beverages. When these bottles are put in a filling machine having support surfaces that raise and lower, it often happens that excessive axial pressure occurs when the bottle is applied against the filling unit, and this pressure is not withstood by the walls of the bottles.

Bottle filling devices have therefore been developed which, instead of having supporting surfaces for the bottoms of the bottles, use a gripping device for lifting the bottle by stiff collars that surround the mouth of the bottle in order to avoid axial overload on the body of the bottles. DE-OS 35 06 250, (U.S. Pat. No. 4,616,684), for example, discloses a bottle filling installation with such gripping devices which are respectively fastened to a vertically movable carriage that mounts to the rotating liquid storage tank. The track for the carriage is then supported externally of the valve body of the filling unit and is rigidly attached at its lower end to the U-shaped gripping device used for engaging the bottle collar. In order to bring about the application force by which the opening of the bottle is pressed against the seal of the filling unit so as to ensure filling that is problem-free when the bottle is in the filling position, this known installation features a pressure spring engaged between the fixed valve body and the movable carriage, said pressure spring acting upwards on the carriage. The carriages have rollers that are respectively raised or lowered at the intake and outlet of the filling installation by a fixed control cam. Since the pressure spring, which is under a minimum of tension when it is in the upper filling position, must nevertheless provide the required sealing force at the bottle mouth, the spring force increases greatly when the bottles are lowered, so that considerable spring force must be absorbed by the control cam or the carriage. This leads to signs of wear, particularly at the control cams. If, on the other hand, the pressure spring is replaced by a work cylinder in this known bottle filling installation, there is a danger of contaminating the filling units and the bottles by the escape of hydraulic oil or lubricating oil in the compressed air, so this solution is thus also not satisfactory.

From EP-OS 222 208 (U.S. Pat. No. 4,721,138) another bottle filling device of the type mentioned in the introduction is known, by which excessive loads on the control paths are avoided. For this purpose, a locking device is provided which locks the carriage into the upper filling position while the required application force for the bottle mouth is brought about by the fact that the filling unit with its sealing element rests on the liquid-containing tank and is vertically movable by means of a pressure spring. With this known bottle filling device the filling unit is raised against the pressure of the spring under tension during the last phase of the bottle-lifting motion, until the locking device locks the carriage. With this type of construction, therefore, a spring force results which only generates the required sealing force. But since the sealing element of the filling unit is arranged so as to be vertically movable under the liquid-containing tank, the clearance between the sealing element onto which the bottle opening is applied during filling and the seat of the liquid valve is relatively large, which, for reasons relating to filling technology, is a disadvantage. Additionally, the hollow spaces and the annular clearance within the sliding sleeve that bears the sealing element are difficult to clean.

The invention at hand is thus given the task of further improving a rotational bottle filling device of the type being considered, such that it completely satisfies the requirements relating to filling technology, and such that its mechanical construction is simple and sturdy.

According to the invention, the gripping device for the bottle collar is arranged so as to be movable in the vertical direction by a carriage and the gripping device is elastically supported on it by means of the springs which provide the required application force for the bottle neck, while the filling unit is fixed against vertical movement at the underside of the filling tank, so that the seal of the filling unit is located directly under the seat of the liquid valve in the filling unit. In this way, the path between the bottle mouth and the seat of the liquid valve is considerably decreased and cleaning problems relating to the filling unit are to a large degree avoided

Since, with the bottle filling device according to the invention, the maximally occurring spring force also corresponds to the desired bottle mouth sealing force, the control path, carriage and filling unit are subjected only to slight mechanical loads, and wear is correspondingly slight.

Two bolts are fastened onto the gripping device 5, guided in a flat plate of the carriage so as to be vertically movable and respectively pressed toward the top by a pressure spring which is arranged between the flat plate 7 and the upper end of the bolts.

According to the invention it is suggested that the locking device features a blind-end bore, advantageously constructed in the wall of the liquid-containing tank, into which a sliding bolt engages when it reaches the upper filling position, said bolt preferably being integrated in the axis of the carriage roller. The blind-end bore is constructed at a height such that during the final phase of the lifting movement of the carriage the pressure springs are stressed. This means that first the bottle mouth runs up against the seal of the filling unit that is arranged in a vertically fixed manner, whereby the gripping device is brought to a halt. But the carriage keeps moving for a short upward distance, until the bolt engages in the blind-end bore, whereby the pressure springs that are arranged between the carriage and the gripping device become stressed to a predetermined degree.

The bolt is advantageously acted upon by a pressure spring in the direction of the unlocking position, in which a head section protrudes over the front surface of the roller that faces away from the liquid tank. The carriage lock is released when the head section of the bolt, upon reaching the upper filling position, runs up against a fixed control cam; that is, one which does not rotate with the bottle filling device, so that the bolt engages the blind-end bore.

It is highly advantageous for the bolt to be held in the lock position by means of frictional forces acting between its seating area and the respective wall of the blind-end bore when spring forces come into effect between the carriage and the gripping device by the placement of the bottle opening on the seal of the filling unit. This means that the carriage only remains frictionally locked in the upper filling position when its gripping device contains the weight of a bottle. If, on the other hand, no bottle is present, then, as a consequence of absent spring forces between the carriage and the gripper device, the frictional forces acting on the bolt are so low that it is moved back to the release position by the pressure spring acting on it; that is, it exits the blind-end bore. The consequence of this is that the carriage with the gripping device is again released and lowered. Thus, the spring arranged between the carriage and the gripping device not only produces the required application force for the bottle mouth, but also simultaneously serves as a control device for unlocking the respective carriage for which there is no bottle. The necessity of having an additional control cam or a suitable contact element for automatically lowering a gripping device without a bottle is eliminated. The automatic lowering of the carriage rotating without a bottle avoids the need for supporting forces, and decreases wear.

The bottle filling device according to the invention has an intake control path on which the carriages are raised into the filling position, and an outlet control path on which the carriages are lowered in a controlled manner by means of rollers. To ensure a control-free entrance of the bolt into the blind-end bore and an unimpeded exit from the blind-end bore, the intake control path and the outlet control path should be designed with a slight excess lift which only needs to be several tenths of a millimeter, in order to minimize or eliminate the frictional forces in the blind-end bore.

As has been stated above, the carriages which do not possess bottles when reaching the top filling position are again lowered in a controlled manner, and a corresponding lowering path is necessarily connected to the intake control path. The lowered carriages are raised again on an elevating path installed before the outlet path on the outlet star wheel of the installation, in order to then be lowered again in a controlled manner with the remaining carriages.

As an alternative to this, the bottle filling installation according to the invention can also be designed such that the carriages or gripping devices that are not supplied with bottles are not lowered automatically, but rather remain in the elevated position until reaching the outlet control path. With this type of embodiment the lowering path of the inlet control path and the elevating path of the outlet control path are eliminated.

According to the invention it is finally recommended that an actuation element of a vacuum valve which is used to suction the bottles before filling is attached in such a position on the wall of the liquid-containing tank that the valve is opened by a carriage that has arrived in the filling position. If a carriage reaches the upper filling position in a system of this type without a bottle and, as a result of this, is automatically lowered again, then the vacuum valve is again immediately closed, so that an undesirable increase in pressure in the vacuum system is avoided

Other specific characteristics of the invention become evident in the following description of a preferred embodiment of the invention, as well as on the basis of the drawing.

FIG. 1 a partially sectioned longitudinal section through an embodiment of the invention when it is in its upper bottle filling position;

FIG. 2 a schematic drawing clarifying the intake control path and the outlet control path;

FIG. 3 a schematic representation of the control paths; and

FIG. 4 is similar to FIG. 1 structurally except that it shows the invention when it has just gripped a bottle by its collar in preparation for lifting the bottle to its filling position.

FIG. 1 depicts a wall 1 of the liquid-containing tank of a continuously operating rotational bottle filling installation which is provided with a carriage track 2 for a carriage 3 On the lower end of the carriage 3 a bracket 4 is fastened, on which a gripping device 5 for bottle collars is resiliently supported.

Moreover, the gripping device 5 is provided with two bolts 6 which have clearance between them, and which penetrate bore holes in a plate 7 of the bracket 4 in a loosely-fitting manner. A compression spring 8 is arranged between the upper end of each bolt 6 and the plate 7, pressing the bolts 6 with the gripping device 5 upward.

In FIG. 4 the bottle gripping device 5 has gripped the bottle 40 under its annular collar 41 so the carriage 3 can lift the bottle in response to rolling onto the stationary cam 12 shown in FIG. 1. Note in FIG. 4 that gripping device 5 has been forced into direct contact with plate 7 because of spring 8 pushing bolt 6 and, hence, the gripping device upward.

An axle 9 is fastened in the upper end section of carriage 3, rotatably supporting a roller 11 by means of a roller bearing. The roller 11 is guided by a control cam 12 in the area of the bottle input intake and the bottle output of the bottle filling installation, whereby the carriage 3 with the gripping device 5 is moved upward and downward in a controlled manner.

A bolt 13 which has a head section 14 is integrated into the axle 9, said head section being acted upon by a pressure spring 15 such that the bolt 13 projects from the front face of the roller 11, facing away from the wall 1 of the liquid containing tank. A ring-shaped projection 16 that is formed on the bolt 13 hereby limits the advance of the bolt 13. The bolt 13 can enter into a blind-end bore 18 in the wall 1 with its end section 17 that faces the wall 1 of the liquid-containing tank when the carriage 3 has reached the upper bottle filling position as it has done in FIG. 1.

For this purpose, a sequence switch cam 19 is arranged in a fixed manner at the position of the control cam 12 where the carriage 3 reaches the upper filling position, whereby the head section 14 of the bolt 13 runs up against the sequence switch cam 19 such that the bolt 13 enters into the blind-end bore 18 with its end section, against the force of the spring 15 that is thereby being compressed.

But before the carriage 3 reaches the upper filling position, the open mouth 42 of a bottle 40 held by the gripping device 5 is placed against the seal of a filling unit 43 which is arranged at the corresponding position under the floor 20 of the liquid-containing tank. As a result of this vertically fixed arrangement, the seal, not visible, in the filling unit 43 can be a minimal distance from the liquid valve, not visible, in the filling unit

Placement of the bottle mouth onto the seal of the filling unit 43 results in the gripping device 5 immediately coming to rest, while the carriage 3 continues a slight motion upward to the locking position in which bolt 13 registers in the blind-end bore or recess 18 as illustrated in FIG. 1. As a result of this additional lifting distance the pressure spring 8 becomes stressed, so &:hat the bottle mouth is pressed tightly against the seal of the filling unit 43.

The force resulting from spring 8 furthermore causes frictional forces in the blind-end bore 18 between the seat area of the end section 17 of the bolt 13 and the adjacent area of the blind-end bore 18, said forces being great enough that the bolt, despite the acting force of spring 15, is held in the locked position. But if the gripping device 5 contains no bottle, then the pressure springs 8 are not stressed, and thus no frictional forces are evoked that can hold the bolt 13 in the blind-end bore 18. In this case the bolt 13 is again moved into the release position after passing the sequence switch cam 19 as a result of the force of spring 15, so that the carriage 3 can lower.

In the upper filling position the carriage 3 activates an actuation element 21 of a vacuum valve 22, whereby the respective bottle is evacuated of air. If, however, no bottle is provided and the carriage lowers, then the vacuum valve 22 is immediately closed again.

FIG. 2 illustrates the position of the intake control cam curve 23 and the outlet control cam curve 24, which are located near an intake star-wheel 25 or an intermediate star-wheel 26 The so-called sealing sector 27 connects to the intermediate star-wheel 26. The filler sector 28 turns in the direction of arrow A in FIG. 2, whereby the carriage 3 is moved upward on the intake control curve 23 until it is locked in its highest position, the filling position, by the fixed sequence switch cam 19.

FIG. 3 illustrates a schematic representation of the intake control curve 23 and the outlet control curve 24. From a lower end position, which is indicated by arrow B, all rollers 11 are guided to the intake control curve 23 in the operating direction C, up to the filling position While the rollers 11 of the carriages 3 provided with bottles are locked in the upper position, the rollers 11a of the carriages without bottles are lowered in a controlled manner on a lowering path. These rollers 11a are finally raised again on an elevated path 30 and, together with the remaining rollers on the outlet control curve (24), are lowered again.