EP1295842A1

EP1295842A1 - Apparatus for capping containers with threaded plastic caps

Info

Publication number: EP1295842A1
Application number: EP02425564A
Authority: EP
Inventors: Mauro Lenzi
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-09-19
Filing date: 2002-09-18
Publication date: 2003-03-26
Anticipated expiration: 2022-09-18
Also published as: EP1295842B1; ITRM20010569A0; DE60209207D1; ITRM20010569A1; DE60209207T2

Abstract

An apparatus for capping bottles with plastic caps threaded in advance, where the cap screwing head (16,216) is only capable of a rotation movement and not a translation movement, wherein the Pick and Place technique can be used, i.e. the technique of drawing the cap to be screwed onto the bottle (BTL) by the screwing head for the next step of application. In the apparatus the bottle is lifted to the head in the cap screwing step and is moved within the head-cap interface integral with the head by thrust means along an angle plate in the cap drawing step.

Description

The present invention relates to an apparatus for capping containers with plastic caps threaded in advance, where the screwing heads do not shift vertically but only rotate about their own axis. It should be noted that under containers mainly bottles and phials are intended.
As known to those skilled in the art, the current apparatus for capping bottles and phials by threaded caps are provided with screwing heads engaging the single bottles by both a shift movement to and from the bottles and a movement of rotation for screwing caps thereon. Because of the need to combine both movements, the construction of such heads and their supports is complex and liable to failures.
The present invention seeks to provide an apparatus in which the screwing heads do not shift vertically as they only make a rotation movement. According to the invention this simplified operation is accomplished by bottle lifting means that lifts the bottle to the screwing head which seizes the cap to be applied before such operation still without making any vertical shift movement.
As better explained below the seizing of caps by the heads according to the invention can be carried out in the apparatus according to the invention by using an angle plate on which gear wheels are engaged as well as by using suitable shaped seizing "cones" formed in the heads.
The apparatus consists of a number of cap screwing heads arranged on a roundabout rotating about the main axis of the apparatus, each such screwing head being put in a rotation motion about its own axis, such rotation motion being taken off from the rotation of the roundabout causing a revolution movement of the screwing heads assembled on a support. Such movement occurs during the rotation of the support of a gear wheel secured to the support of each head, such gear wheel engaging a further gear wheel, which is secured to the external casing of the apparatus so that an epicyclical system is provided. A device which is stationary with respect to the external structure of the apparatus is able to insert a cap to be screwed into a seizing "cone" of each screwing head while the latter traverses above the device during the revolution movement about the main axis.
According to the invention the bottle which is of plastic material in the embodiment shown and is provided with a support collar and to which the cap has to be screwed is engaged by a fork collar provided with seizing teeth while it is in the lowest position and is lifted to the screwing head through the collar which is fixed to an axis sliding vertically in its guide without rotating about its axis because of the engagement of a key. Therefore, the axis of the bottle is steadily aligned with the axis of the cap screwing head. A cam and a pin integral with the axis drive the longitudinal stroke of the axis.
The invention will now be described in more detail with reference to the accompanying drawings, in which:
Fig. 1 is a top plan view of the whole apparatus;
Fig. 1A is a similar view of a particular of Fig. 1;
Fig. 2 is a cut-away diametrical section showing two screwing heads in opposite diametrical positions;
Fig. 3 is a rather schematic view of a section similar to Fig. 2 in enlarged scale in which some construction details have been omitted;
Figs. 4 and 5 are fragmentary partial sections of a screwing head at different steps of operation;
Fig. 6 shows an alternate embodiment of the apparatus of Figs. 2 and 4 having a rigid construction;
Fig. 7 is a fragmentary view of an axial section in enlarged scale showing the step in which a cap is caught by one screwing head;
Figs. 7 (A,B,C) show in detail the cap feeding and catch members as used in the apparatus;
Figs. 8 (A,B,C) show a detailed, fragmentary view of the step in which a cap is caught by the seizing cone.
The main components of the apparatus are shown in the schematic cut-away top plan view of Figs. 1 and 1A in which numeral 20 designates the roundabout of the screwing heads 16, numeral 21 designates the input of the bottles BTL to be capped, numeral 22 designates the output of the capped bottles BTT, and numeral 23 designates the cap feeding system.
The apparatus includes (Figs. 1 and 2) a fixed portion consisting of a cover disc 11 supporting an upper fixed hub 12, and cylindrical members of an external wall 13. The apparatus includes in its inside a shaft 14 at the lower side driven in rotation by an electric motor (not shown). Shaft 14F is not rotating.
Pivotally connected to rotating shaft 14 and arranged between hub 12 and such shaft 14 is a cylindrical hollow support 15 to which the roundabout of screwing heads 16 is secured, each screwing head being supported by a device 18 secured outside the rotating support 15. In the embodiment shown, the roundabout includes ten screwing heads 16.
Each screwing head support device includes (Figs. 2 and 4) a disc 30 integral with the rotating shaft 15 to which also a sleeve 31 is secured in which a member 32 is slidable vertically, at the base of which a fork collar 33 receiving the neck of the bottle BTL to be capped is supported.
As plastic bottles provided with a support collar have to be capped in the embodiment described and illustrated, fork collar 33 is provided with teeth 44 that stick into the plastic material of the collar of bottle BTL during the compression step against screwing head 16, Fig. 2A, and prevent the bottle from rotating during both cap screwing and tightening steps. The load, which is needed to stick teeth 44 and calibrate the cap compression thrust onto the bottle, is provided and calibrated by spring 81 placed inside screwing head 16.
Secured to the upper portion of the slidable member 32 (Fig. 2) is a pin 42 to which a cam follower roller 34 engaging an elicoidal channel cam 35 (Fig. 1B) is disposed. Such channel cam is formed in the outer surface of a fixed cylindrical sleeve 36 coaxial with hub 12 and secured to cover disc 11.
It is self-evident that the pitch of elicoidal channel cam 35 is equal to the vertical translation length of slidable member 32.
Cap screwing head 16 (Fig. 4) consists essentially of a tubular body 50 carrying a gear wheel 52 in such a position as to mesh with the fixed gear wheel with large diameter 40 integral with the cylindrical side wall members 13 of the stationary portion of the apparatus (Figs. 1 and 2).
In addition to the necessary components to provide a rolling friction, hermetic barrier against the entrance of dust, seepage of liquids and other, screwing head 16 includes an outside body 73 in which a sleeve 74 is inserted, and an inside cylindrical body 75 inserted in such sleeve 74.
Cylindrical body 75 has a portion with greater diameter 76 forming a step 77, and a similar step 78 is formed in sleeve 74 between the lower portion and the upper portion 79 with greater diameter.
Thus, between members 74 and 76 slidable on each other a cylindrical space with annular section 80 is formed which receives an elicoidal compression return spring 81 able to contrast any relative axial movement of the two members.
Screwing head 16 further has an axial core or rod 82 carrying at the upper side a head 83, a second elicoidal compression spring 84 being provided between head 83 and mouth 85 of cylindrical body 75 around axial core 82.
Central rod 82 is assembled in a stable position raised with respect to the seizing cone 88 of cap CPS and is inserted together with the latter in such cone aiming at expelling the cap by a downward shift caused by the thrust of rod head 83 by the stationary angle plate cam CPI. Such arrangement serves to overcome the problem that would arise in case of fortuitous lack of a bottle under the head with the result that cap CPS would remain inside cone 88 as it cannot be applied to the bottle. As a result, cone 88 takes the position again to receive a new cap from the Pick-and-Place device (trade name) even if it still contains the preceding not applied cap, with the consequence of failure in the operation cycle and possible damages of the head.
Another advantageous feature of the invention consists in the friction assembly, which the screwing head indicated at 100 in the exploded fragmentary view of Fig. 5 is equipped with. Such assembly secured to the body is illustrated in detail in such figure and forms a magnetic friction which can be calibrated continuously without need of tools. Furthermore, such friction has a very reduced inertia.
The assembly includes an annular support 101 and comprises bearings 102, which are held between annular member 103 and axis 112. Thus, a defined, reproducible positioning of bearings 102 is achieved with the resulting interchangeability of the whole assembly 100.
The magnetic friction consists of two annular tracks 104 and 105 in which a number of permanent magnets are disposed, with track 105 rotating together with the axis and track 104 being put in rotation by the attraction force of the magnets of the two tracks that produce the driving torque.
When applying to track 104 a counteractive torque, the maximum value of the driving torque can be reached, whereupon the rotation stops. The driving torque which is then the maximum torque applicable by the cone 88 to the cap to be screwed is a function of the distance between magnetic tracks 104 and 105 so that upon varying such distance the tightening torque applied to cap CPS steadily contained in the cone is varied.
Magnetic track 105 is integral with toroidal member 106, which is connected axially to member 101 through thread 108. Both members 101 and 106 have a toothing 109 with the same geometric dimensions at the outside cylindrical peripheral surface so that the outside ring 110 provided with an inside compatible toothing can slide axially on both toothings and, in case of engagement of both toothings, a steady mesh between members 101 and 106 that cannot rotate to each other is obtained.
With such a construction members 101 and 106 take a relative constant position.
If outside ring 110 is lifted, the toothing of member 106, that can then rotate, is disengaged and by means of thread 108 it can come near or move away from member 101. It is possible to block the position of members 101 and 106 again by causing the toothing to mesh with outside ring 110. Because of the geometry of the system, upon varying the relative positions of members 101 and 106, the distance between magnetic tracks 104 and 105 as well as the driving torque and then the tightening torque of the cap on the bottle is varied by the same amount.
Elastic ring 111 has the purpose of keeping outside ring 110 in a steady, stationary position with meshed toothing. It should be noted that the geometry of the assembled apparatus is such that outside ring 110 cannot be removed by shifting it upwards as it knocks against member 73, thus keeping its predetermined position with respect to member 101 in order to allow the positions, that have been determined during the assembling, to be calibrated and regulated.
Axis 112 is secured to bearings 102 through ring 103 and carries magnetic track 104 embodied therein as well as cone 88 containing the cap to be screwed onto bottle BTL.
It should be noted that the whole assembly 100 can be applied onto other screwing heads used with conventional capping machines, thus taking advantage of such assembly, i.e. tightening means with very low inertia and easily and quickly adjustable torque according to known calibration without using tools.
Fig. 7 shows the component of the device to carry out the Pick and Place technique (trade name), i.e. the component that "inserts" cap CPS into cone 88 integral with screwing head 16.
Such device consists essentially of an axis 89 secured through flange 90 to disc 11 of the apparatus.
Member 91, i.e. the main body of the rotating member, is secured to bearings by an elastic ring and can rotate with respect to axis 89. Star wheel 92 is secured to member 91 through a flange and is shaped and positioned such as to be put in rotation about axis 89 by means of cylinders 73 entering spaces 97A while the roundabout of the screwing heads rotates about the central axis of the apparatus.
A thin shaped disc 93 with recesses 97 is secured to member 91 and blocked between flanges 94 and 95.
Shaped disc or star wheel 93, see Figs. 7A, 7B, 7C, has the same number of teeth as star wheel 92 and is blocked between flanges 94 and 95 with recesses 97 exactly timed with recesses 97A of star wheel 92 so that caps CPS driven by star wheel 93 on plate 99 and the slide channel formed of outside guide 100 and upper guide 102 are timed with cone 88 in the coincident position 101 of Fig. 7A. Such position is determined by the contact point of the rotation circumference of screwing heads 16 with the circumference of recesses 97 of star wheel 93 and then of caps CPS put in rotation by such star wheel.
The mutual positions of elements 92, 93, 99 and 89 are clearly shown in the section view of Fig. 7.
With reference to Fig. 8A there is shown the method of inserting cap CPS onto cone 88 without the need to lower screwing head 16 as it normally occurs in the currently used capping machines working with plastic caps.
The method consists of using an angle plate 105 on which wheel 93 pushes the cap and lifts it to the inside of cone 88. Angle plate 105 has such a slope as to allow the insertion of cap CPS inside cone 88 to be initiated at the area around the coincidence point 101 and to be further lifted thereafter so that at point 106, i.e. before star wheel 93 stops pushing the cap, the latter is already under full control of cone 88, i.e. pushed and partially inserted into the inside of the latter, as shown at 107, so that cone 88 can carry on to trail the cap by its movement along angle plate 105 till the top of the latter. Angle plate 105 ends in a plain length which serves to make completely straight the cap inside cone 88.
The inside shape of cone 88 is such as to facilitate and to allow the insertion movement of the cap in its inside when the latter is inclined. This is accomplished by a mouth 109 of the cone having an opening angle, which is equal to the slope of angle plate 105. Also the shape of angle plate 105 is such as to allow the described movement with the suitable graduality by regulating angle α of mouth 109 and the final slope 110 before the horizontal plane 108.
Balls 211 inside the cone are timed with the seizing teeth of cap CPS and have a dual function: firstly orienting the toothing of the caps during the insertion into the cone, with the corresponding teeth inside the cone allowing the screwing and the tightening of cap CPS onto the bottle; secondly holding the cap inside cone 88 during the way between the end of the angle plate and the support over the bottle BTL of Fig. 1.
Another preferred or alternate embodiment of each screwing head/bottle lifting system assembly is depicted in Fig. 6, in which only the left half of the apparatus of Fig. 2 is shown by simplicity, and consists of rendering the screwing head not elastic with respect to the compression of the bottle and rendering the bottle lifting system elastic. Such a construction allows the screwing head assembly to be simplified so that it just rotates about itself and is only provided with the friction to limit and to regulate the cap tightening torque and not with mechanical compression means. In Fig. 6 all of the elements corresponding to Figs. 2 and 5 are designated by the numerals beginning with 200 so that screwing head 16 of Fig. 1 becomes the element 216 of Fig. 6.
In such construction the magnetic friction assembly of Fig. 6 is the same as assembly 100 of Fig. 5. More particularly, the whole friction assembly of the screwing head is connected in the same way through a thread to rotating axis 250, which is supported by the bearings.
Cam 236 lifts through idle pin 234 bottle BTL resting on toothed collar 233 secured in turn to bracket 233S. The assembly consisting of axis, bush, tongue, spring, guide and screw has the function of the axis of Fig. 2 with the features of being axially elastic due to spring 253 but not rotatable, as well as axially sliding in the guide bush secured to body 230 but not rotatable because of suitable keys. Therefore, also in such construction the axis of bottle BTL is held coaxial to screwing head 216 in its coming near or moving away from the screwing head.
When the bottle is lifted from the toothed collar 233 and comes to the end of stroke with the cap inside cone 288, the necessary excess in the bottle lifting stroke compresses spring 253, thus allowing the teeth of collar 233 to run into the plastic material of the bottle collar and to prevent the latter from rotating.
The compressed spring also allows the vertical stroke for screwing the cap onto bottle BTL to be compensated still keeping its compression.
In operation, Fig. 7A, because of the slope of the feeding channel 108 and an air blow, the caps CPS come to plate 99 where they are caught by recesses 97 of shaped disc 93 which is in turn rotated by heads 16 carried by the roundabout. The bottles to be capped BTL coming from wheel 21 (Fig. 1) are engaged by fork collars 33 integral with slidable members 32 which are lifted by cam system 34-35. Therefore, the bottles are brought under the head and cone 88 in which a cap drawn as illustrated in Fig. 8 is already inserted.
As it is evident, heads 16 are rotated because of the engagement of their gear wheels 52 with fixed gear wheel 40 during the rotation of the roundabout integral with shaft 15. The capped bottles BTT are then extracted by wheel 22.

Claims

An apparatus for capping containers with plastic caps threaded in advance, where the screwing heads do not shift vertically but only rotate about their own axis, comprising several heads (16) carried by a roundabout around a shaft (15) put in rotation by an electric motor for screwing threaded caps (CPS) onto bottles to be capped (BTL), characterized in that the body (50) of each head (16) has a small gear wheel (52) meshed with a conjugated gear wheel (40) with large diameter integral with the construction of the apparatus so that the requested rotation of each head (16) to apply the cap (CPS) contained in cone (88) of the screwing head is taken off from the rotation of the whole roundabout carrying screwing heads (16) inside gear wheel (40).
The apparatus according to claim 1, wherein the outer body (73) of each head is integral with a cylinder (31) in which a cylindrical slidable member (32) carrying a fork collar (33) engaging the neck of the respective bottle to be capped (BTL) is disposed, said slidable member (32) being connected to a pin (42) carrying a roller (34) received in an elicoidal channel cam (35) formed in a cylindrical body (36) secured to the cover (11) of the apparatus so that the rotation of the roundabout causes said roller to slide along the channel cam (35) and to lift the slidable member (32) in sleeve (31) with the result of a lifting of said collar (33) and bottle (BTL) resting thereon so as to come in contact with the relative head (16) and cap (CPS) received in cone (88) and then applied to the bottle.
The apparatus according to claim 2, wherein said fixed construction carries a hub with a shaft (89) that is inserted therein and supports a shaped disc (93) which is provided with recesses (97) seizing the caps (CPS) and is meshed with a star wheel (92) having recesses (97A) that receive heads (16) and/or body (73) rotating together with the roundabout, said disc (93) rotating at a small distance from a stationary plate (99) to which the caps (CPS) are fed, an angle plate (105) being provided to cause the caps (CPS) received in said recesses (97) to rise until they are inserted into the relative cone (88) of each head (16) which will then be brought by the roundabout over the bottle (BTL) to be capped which are lifted to the corresponding heads by the movement of said collar (33).
The apparatus according to claim 1, wherein each head (16) is provided with a magnetic friction device comprising a first annular magnetic track (105) facing a second annular magnetic track (104) across a small gap, both magnetic tracks (104, 105) being carried by a collar integral with said cone (88) and the body of a collar (106) integral with the body of the head (16), respectively, an adjustable gap between said magnetic tracks (104, 105) being provided in order to regulate the tightening torque transmitted therebetween, such adjustment of the gap occurring by disengaging and engaging a toothed sleeve (110) which engages both members (101, 106), thus determinig the gap between magnetic tracks (104, 105).