GB2098161A - Article detecting device in wrapping machines - Google Patents

Abstract

In prior art detecting devices (eg. GB 2046695), comprising feelers mounted on an actuator wheel, cams and cam followers, if two or more successive articles are absent from a wrapping head, wrapping material may be partially fed because of the dwell time of the cams between one detection sequence and the next. The instant device obviates this problem by providing two actuator wheels (5, 6) on a common shaft (4) which alternately detect the presence, or absence, of articles by feelers (7, 8) and separately dis-engage feed rollers (2, 3) via levers (13a 14a), the dwell time of one wheel being out of phase from the other so that the feed rollers only engage if there is an article present. <IMAGE>

Description

SPECIFICATION Device for interrupting the draw-off of strip material The invention relates to a device for interrupting the drawing off of a web of packaging material in the absence of goods to be packed, especially sweets in the holding elements of a wrapper wheel on a continuously operating high-speed wrapping machine, using a pivotably mounted feeler lever for ascertaining the presence of a sweet in the holding elements, by means of which the disengagement of a conveyor roller can be initiated in the case of absence of a sweet, by a roller lever situated on an actuator wheel with externally pivotably mounted cam segment and setting lever.

Several devices for interrupting the feed of packing material in the absence of a sweet on discontinuously working packing machines are known. The feeler levers for ascertaining the presence of a sweet are arranged on these machines beside the feed plate. The sweets lie in recesses situated on the circumference of the feed plate.

In the absence of a sweet, the feeler lever extends into the empty recess and effects a disengagement of the conveyor roller. Since the feeler levers cannot be arranged in the immediate region of the packing material feed, for constructional reasons, these known devices differ in assembly by means for storage of the setting movement. Due to the storage of the setting movement the conveyor roller is disengaged only when the empty recess comes into the region of the working elements.

Thus it is known to use a Maltese-crosstransmission which is operable by an electromagnet.

This Maltese-cross-transmission is connected with a cam which alternately effects the coupling and uncoupling of the drive wheel at every step of the transmission (GDR-PS 59,038).

Moreover a storage wheel with axially displaceable bolts is known. The axially displaceable bolts are shifted by means of an electromagnet (GB-PS 845,663).

Finally an embodiment of this kind is also known which likewise comprises a storage wheel with axially displaceable bolts (GDR-PS 127,713). This storage wheel works without electrical componenets, the setting movement of the bolts being initiated by mechanical parts. These devices are usable only for discontinuous operation, since the sensing and the interruption of the feed are designed for the detent time of a working cadence.

Such a device is also known which is suitable for continuous operation. This device is characterised in that beside the wrapper wheel there is arranged a feeler control wheel rotating in synchronism therewith, with radially pivotably mounted feeler levers.

The feeler levers are mounted so that in the absence of a sweet they arrest a roller lever for a short time, in order, as in the embodiments already described above, to disengage the conveyor roller only when the corresponding holding element is situated at the transfer position (GDR-PS 138,635). However this embodiment still has the disadvantage that in the absence of two sweets one behind the other in the holding element of the wrapper wheel, the cam segment is lowered by the emerging roller and raised again by the entering roller. This leads to an uncontrolled application of the conveyor roller and thus to an interrupted feed of packing material.

The invention has the purpose of increasing the output of the device.

The problem of the invention consists in achieving a functionally reliable manner of operation of the device, with continuous operation of the wrapping machine, even if several sweets should be missing in succession in the holding elements of the wrapper wheel.

According to the invention this is achieved by two actuator wheels arranged side-by-side on a common control shaft, on each of which at least one feeler lever, angled off axially parallel as far as the middle of the two actuator wheels, is pivotably mounted on a pivot journal in such a way that on one revolution of the actuator wheel it comes to abut in alternation with the feeder lever of the adjacent actuator wheel on the sweet situated in the holding elements and in the absence of a sweet comes into contact with a cam segment allocated to each actuator wheel, by radial pivoting out by means of a roller lever secured on the pivot journal.

Thus reliable disengagement and application of the conveyor roller are rendered possible, even in the absence of two sweets in succession, since the actuator wheel allocated to the actuation operation permits the corresponding cam segment to run out, while for the next actuation a corresponding setting movement can already be imparted to the other cam segment through the adjacent actuator wheel.

According to a further feature a spring-loaded pawl lever is arranged on the actuator wheels for the temporary arresting of the roller lever in pivoting out. Thus it is possible to fix the time of the setting movement and also to store the moment in time of the execution of the setting movement. The invention is finally also characterised in that the cam segments allocated to each actuator wheel are arranged on a common shaft. Thus only one setting lever advantageously acts upon the conveyor roller.

The invention is explained in an example of embodiment in the drawing, wherein:- Figure 1 shows a perspective view, Figure 2 shows the same as above, with the conveyor roller disengaged.

The device is a componenet of a high-speed sweet-packing machine (not illustrated), of which only one pair of holding elements 1 of the wrapping wheel is contained in the drawing. With the aid of two conveyor rollers 2,3 individual cut pieces are fed to the holding elements 1 elsewhere, which are cut from a web B of packing material by cutting tools (not illustrated).

The device for interrupting the draw-off in the absence of sweets consists essentially of two actuator wheels 5, 6 arranged side-by-side on a common control shaft 4, on which wheels feeler levers 7, 8 are pivotably mounted. Two feeler levers 7,8 are situated in diametric opposition on each actuator wheel 5,6.

The feeler levers 7,8 are angled off axially parallel with the control shaft 4 to reach to the middle in such a way that a feeling position they come to abut with their free end on the sweet situated in the holding elements 1. On the actuatorwheel 5, the feeler levers 7, 8 are in each case secured inwardly on a pivot journal 7a, 8a on which a pawl lever 7b,8b is secured on the outer side of the actuator wheels 5,6.

To each pawl lever 76, Sb there is allocated on the actuator wheels 5,6 a pivotable roller lever 9 the free end of which, directed towards the pawl lever 7b,8b, has a notch having no reference numeral. The pawl lever 7b, 8b and the roller lever 9 are subject to the initial tension of a tension spring 10, 11 secured on the actuator wheel 5, 6. The pawl lever 7b, 8b is so dimensioned that in the normal position it rests radially outwardly on the roller lever 9. The roller of the roller lever 9 moves on a non-displaceable centrai cam 12, the cam path af which is formed so that the roller lever9 is briefly pivoted radially outwards on reaching of the feeling position of the feeler lever 7, 8.In this position of the roller lever 9 the roller protrudes outside the circumference of the actuatorwheei 5,6.

The device is further completed by the parts necessary for the displacement of the upper conveyor roller 3. On each of the actuator wheels 5,6 there lies radially outwardly an arcuate cam segment 13, 14 which in the example of embodiment with two feeler levers 7,8 per actuator wheel 5, 6 occupies about 90 of the circumference. These two cam segments 13, 14 are situated the end of a pivot lever 13a, 14a which is mounted in each case pivotably on a common non-displaceable shaft 15.

On the free ends of these pivot levers 1 3a, 1 4a there are arranged stop rollers 13b, 14b which are connected with a pivot mechanism, described in greater detail below, for the upper conveyor roller 3. In contrast to the non-displaceable lower conveyor roller 2, the upper conveyor roller 3 is mounted raisably and lowerably on a bell-crank lever 16 on both sides. These bell-crank levers 16 are mounted on a shaft (not illustrated) and are connected at the other end at the level of the stop rollers 1 3b, 1 4b by a stop bar 17. A tension spring 18 engages centrally with this stop bar 17, so that thus the upper conveyor roller 3 under force engagement comes to rest on the material web B or the cam segment 13,14 comes to abut through the pivot levers 13a, 14a on the actuator wheel 5, 6.

The manner of operation of the device as described is the subject of the following description.

The holding elements 1 are arranged on a wrapper wheel (not illustrated) which is driven continuously.

The feeler levers 7, 8 of each actuator wheel 5,6 come to abut in alternation on the sweets at the feeler point on the circumference of the wrapper wheel, the actuator wheels 5, 6, by means of the control shaft 4, rotating likewise continuously in adaption to the wrapper wheel in the direction of the arrowx. In the normal case, that is when the holding elements 1 are occupied, the upper conveyor roller 3 remains in the conveying position so that the feed of the material web is not interrupted. In this condition the feeler levers 7,8 remain in their position so that the pawl lever 7b, 8b secured on the pivot journal 7a, 8a on the other side of the corresponding actuator wheel 5, 6 continues to rest on the radial end of the roller lever 9. Thus the roller lever 9 remains in its position so that the cam segment 13, 14 is not contacted by the roller 9a thereof.This conveying position is illustrated especially in Figure 1, the two actuator wheels 5,6 occupying this ineffective position.

In the absence of a sweet in the holding elements 1, as illustrated in Figure 2, firstly the feeler lever 8 pivots somewhat further radially out since it does not meet a sweet. At this point the roller lever 9 was already pivoted outwards by the cam 12, so that the pawl lever 8b can pivot back into the notch thereof without resistance. In the continuing rotation of the actuator wheel 6 the cam lever 9 is held in the outwardly extending position by the pawl lever Sb.

Thus the roller 9a of the roller lever 9 comes to abut on the cam segment 14 and pivots the latter radially outwards. The pivot lever 13a here comes into contact with the stop bar 17, whereby the conveyor roller 3 is lifted out by means of the bell-crank lever 16. The blocked position of the pawl lever Sb is eliminated by means (not illustrated) after the cam segment 14was passed by the roller lever 9. Since the feeling operation proceeds in a continuous operation, the next holding element 1 is already explored by the feeler levers 7 of the adjacent actuator wheel 5. If now a sweet is again situated in this next holding element 1,the position of the neighbouring actuator wheel as already described results. However in the absence of a sweet twice in succession in the holding elements 1 the conveyor roller does not come into application in the meantime, since the cam segment 13 is pivoted out radially by means of the actuator wheel 5. Thus the conveyor roller 3 remains in the upper position and the cam segment 14 of the actuator wheel 6 which previously came into effect can return into its initial position without interference with the setting movement.

Claims (6)

1. A device for interrupting the drawing off of a strip web of packing material in the absence of articles for packing, by means of which the disengagement of a conveyor roller can be initiated in the absence of an article by a roller lever situated on an actuator wheel with outwardly pivotably mounted cam segment and setting lever, comprising two actuator wheels arranged side-by-side on a common control shaft, on each of which at least one feeler lever angled off axially parallel as far as the middle of the two actuator wheels is mounted pivotably on a pivot journal in such a way that on each revolution of the actuator wheel this lever comes to abut in alternation with the feeler lever of the adjacent actuator wheel on the article situated in the holding element and in the absence of an article comes into contact with a cam segment allocated to each actuator wheel by radial pivoting out, by means of a roller lever secured on the pivot journal.

2. A device as claimed in Claim 1, wherein on the actuatorwheelsthere is arranged a spring loaded pawl lever for the temporary arresting of the roller lever in its pivoting out.

3. A device as claimed in Claims 1 or 2, wherein the cam segments allocated to each actuator wheel are arranged on a common shaft.

4. A device as claimed in Claim 1 and substantially as described with reference to the accompanying drawings.

5. A continuous high-speed sweet wrapping machine having a wrapper wheel with sweet holding elements, a pivotably mounted feeler lever for ascertaining the presence of a sweet in their holding elements and a device for interrupting the drawing off of a web of packing material in the absence of sweets for packing, by means of which the disengagement of a conveyor roller can be initiated in the absence of a sweet by a roller lever situated on an actuation wheel with outwardly pivotably mounted cam segment and setting lever, said device having two actuator wheels arranged side-by-side on a common control shaft, on each of which at least one feeler lever angled off axially parallel as far as the middle of the two actuator wheels is mounted pivotably on a pivot journal in such a way that on each revolution of the actuator wheel this lever comes to abut with the feeler lever of the adjacent actuator wheel on the sweet situated in the holding element and in the absence of a sweet comes into contact with a cam segment allocated to each actuator wheel by radial pivoting out, by means of a roller lever secured on the pivot journal.

6. A continuous high-speed sweet wrapping machine substantially as described with reference to the accompanying drawings.