Abstract:
The invention relates to a linear conveyor device ( 30 ) for objects ( 20 ), whereby the objects are taken by drive tongues ( 40 ), arranged on circulating toothed belts ( 31, 32 ). The objects are secured against lifting off the conveyor device, particularly mechanically, by a cover strip ( 50 ). Light objects can thus also be conveyed at high rate in intermittent operation.

Description:
IDENTIFICATION OF RELATED APPLICATIONS  
       [0001]     This application claims priority from Swiss Patent Application No. 1357/04 of Aug. 18, 2004 and from Swiss Patent Application No. 1434/04 of Aug. 30, 2004, the entire disclosures of which are incorporated herewith by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     The invention concerns a method for conveying objects to be processed according to claim  1  and a device for the conveyance of objects according to claim  14 . A preferred use or method is in the field of making package covers each of which includes a cover ring and a tear off foil arranged over the ring.  
       STATE OF THE ART  
       [0003]     It is known to provide covers for cans or other pot-like packages, such as metal covers permanently fastened to the upper sides of the packages, which covers form a removal opening which up to the time of first use of the package contents is closed by a tear-away foil, especially a metal foil, applied to the remainder of the cover by heat sealing. An additional plastic cover arranged over the metal cover makes the package recloseable during the useful life of the package contents. A customary processing apparatus for the making of such metal covers is explained in the following with the assistance of  FIG. 1 .  FIGS. 2-8  help to explain the steps involved in the making of such cover.  
       DESCRIPTION OF THE INVENTION  
       [0004]     The basic object of the invention is to make possible the stepwise conveyance of objects to processing stations at high stepping rates, especially for the cover processing, and to provide a correspondingly fast and simple working apparatus for carrying out the conveyance. These objects are solved by the method according to claim  1  and by the apparatus according to claim  14 .  
         [0005]     By the conveyance of the objects in essentially one plane and the securing of the objects against being lifted during the advancement steps or advancement periods, a high stepping rate and a simple layout of a manufacturing line is possible.  
         [0006]     In a preferred design of the conveying device such device includes toothed belts spaced from one another and having arranged thereon driving tongues or supports for the objects to be conveyed. Preferably the toothed belts are adjustable in regard to their spacing so that a format change to suit the conveying device to different shapes and/or sizes of the conveyed objects can be quickly made. For another way of making a format change in a simple way the toothed belts, with their driving tongues, can be exchanged for other toothed belts with differently arranged driving tongues. It is preferred that the driving tongues not be shaped in specific conformance to particular objects to be conveyed, and instead that they be suited to the size and shape of the objects or covers to be transported only by the mentioned adjustment steps. In place of one of the two toothed belts a different support means can be provided for the objects to be conveyed, for example a rail.  
         [0007]     It is further preferred that the drive tongues in addition to being fastened to the toothed belts be guided in a guide which inhibits even only momentary deflections or tippings of the driving tongues out of the conveying plane and thereby makes possible very high vibration free stepping rates. The securement against lifting of the objects from the driving tongues is achieved by a stationary mechanical securing, for example by a cover which covers the conveyor in the receiving area of the objects during the conveying movement so that thereby the objects cannot be lifted upwardly from the driving tongues. Preferably the cover and the guide for the driving tongues are unified in the same structural element, such as a cover strip for the toothed belts. The securement against lifting can however also be achieved, for metallic objects, by magnetic means, and especially by using only magnetic means. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     In the following the state of the art and exemplary embodiments of the invention are explained in more detail with the help of the drawings. The drawings show;  
         [0009]      FIG. 1 —A schematic side view of a conveyor device according to the state of the art;  
         [0010]     FIGS.  2  to  8 —Views showing sections of metal covers to explain their manufacture;  
         [0011]      FIG. 9 —A view showing an embodiment of a conveyor device according to the invention;  
         [0012]      FIG. 10 —A view of the toothed belts and drive tongues of the device of  FIG. 9  in a first position;  
         [0013]      FIG. 11 —A view of the toothed belts and drive tongues of  FIG. 9  in another position;  
         [0014]      FIG. 12 —A partially cut away detailed view of a device of the invention;  
         [0015]      FIG. 13 —A partially cut away detailed view of another device of the invention;  
         [0016]      FIG. 14 —A view showing the output end of the conveyor device;  
         [0017]      FIG. 15 —A view of a variant conveyor device of the invention having a different support means in place of one toothed belt. 
     
    
     WAY FOR CARRYING OUT THE INVENTION  
       [0018]     With the help of FIGS.  1  to  8 , the state of the art concerning a processing machine for the making of metal covers with a tear-off foil is briefly explained.  FIG. 1  shows a schematic side view of such an apparatus  1  which on a machine frame  2  has several processing stations  3  to  9 . A conveyor device  10 ,  13 ,  14  moves objects in the forward direction, which is indicated by the arrow C, from a stack  11  at the starting end of the device to the other end of the device where the objects by way of chutes are moved into the repositories  16 ,  17 . The objects are taken from the stack  11  in a known way and are put onto the conveyor device. This device has two long rails  10  arranged respectively at the opposites sides of the objects, which rails let the objects, lying on supports  10 ′ at the stations  3  to  9  move upwardly in the direction A upon raising of the rails  10  by means of the drive  14 . Then by a crank drive  13  the rails and the objects now carried by the rails are moved forwardly in the direction of the arrow B (directed in the same direction as the arrow C) forwardly by a given step amount.  
         [0019]     Thereafter the rails are lowered downwardly in the direction of the arrow A so that the objects are again returned to a supported position at the stations  3  to  9  on supports  10 ′. Then the rails at  10  are moved rearwardly in the direction of the arrow B oppositely to the arrow C below the now otherwise supported positions of the objects in order to be ready to carry out a new cycle of the described stepping process. The objects between the times of their transport are located at rest positions along the length of the conveyor device or are located in the processing stations at which they are processed. After the processing steps of all the processing stations are completed a new forward movement takes place.  
         [0020]      FIG. 2  shows stacked metal cover blanks  20  as an example of the conveyed objects, which blanks are provided in the stack  11 . These blanks  20  are, for example, round metal discs of, for example, 11 cm diameter. Of course other basic forms are possible without ado, for example square or rectangular discs and other diameters or sizes. The blanks  20  have already been formed in a non-illustrated processing machine at their edges as shown in  FIG. 2 . In  FIG. 2  and in following FIGS.  3  to  8 , only a section of an entire disc is illustrated in order to simplify the drawings.  
         [0021]     In the first processing station  3  of  FIG. 1  an opening is stamped into the disc by way of a stamping process using upper and lower work tools, which opening is visible in  FIG. 3 , where the edge of the opening is indicated at  21  and the stamped out round disc is indicated at  27 . This disc  27  proceeds as waste into the container  12  of  FIG. 1 . The stamping station  3 —as is the case also for the subsequent stations—is driven by a drive  15 .  
         [0022]     In the processing station  14  the edge  21  is bent downwardly to create the flange illustrated at  22  in  FIG. 4 .  
         [0023]     The annular cover blank  20  now is transferred to the processing station  5  in which a foil  25  is placed over the opening of the cover and is fastened thereto by heat sealing, as is shown in  FIGS. 5 and 6 . The metal foil  25  for this is provided in a known way with a plastic material layer on its underside. The needed round foil blank  25  as a rule is stamped from a wide foil strip in station  5  and is placed in the middle recess of the annular disc. By means of the heat sealing station the foil under the effect of heat is pressed onto the edge of the round recess of the blank  20 , so that the foil  25  becomes a tightly connected with the metal cover  20  by melting and subsequent cooling of the plastic layer. This is known and need not be described in more detail here. In any event for the cooling a cooling processing station  7  can be provided.  
         [0024]     In the processing station  8  the foil  25  is provided with a embossing  24  ( FIG. 7 ), and the flange  22  is beaded into the finished edge  23 .  
         [0025]     In a test station  9 , likewise shown as a processing station, the finished cover is now subjected to a testing process which as a rule includes a sealing test for the tear off foil  25  applied to the cover. If the foil is found to be tightly fastened to the remainder of the metal cover, the metal cover is moved into the receiver  16  for the finished covers. If a leaky condition is found, the cover is moved by way of the other illustrated chute into the waste container  17 .  
         [0026]      FIG. 8  shows in perspective view a conveyor device  30  according to one embodiment of the invention. This conveyor device  30  is designed for the transport of cover shaped objects of the depicted kind but it can also be used for the conveyance of other objects with the changes necessary for that being capable of being made by persons skilled in the art without anything further. The conveyor device serves again for the stepwise advancement of the objects through a number of processing stations, which preferably are processing stations for the making of covers as previously described. These processing stations are not shown in the  FIG. 9  and it will be clear to persons skilled in the art how they can be arranged along the length of the conveyor device to carry out the involved processing. In  FIG. 9 a  further conveyer device  30 ′ is arranged next to the conveyor device  30 . These two conveyor devices can be driven in common by the same drive  33 ,  37  or each can be provided with its own drive. Additional conveying devices can be provided in the same way in order to increase the total count of the objects conveyed. With the illustrated conveyor device  30 , which is described in detail in the following, objects or covers can be conveyed at higher rates of, for example, 200 objects per minute, and with reproducible partial steps between the processing stations. It further implements a flexible concept for accommodating a large format range of the objects or covers, so that in the case of round covers for example their diameters can range from 50 to 200 mm and the covers can have diverse rectangular shapes such as those, for example, for much wanted fish packing cans. The conveyor device further is designed as a compact module which can be used for one track installations or, as shown, for multiple track installations.  
         [0027]     In the illustrated preferred embodiment the conveyor device has two toothed belts  31  and  32  which especially with their upper surfaces lie in the same plane, and therefore run in a co-planar manner, and which at the beginning and end of the conveyor device are guided over end rolls  34 ,  36  so that an endless toothed belt drive results and has the length needed for the number of processing stations involved. The stepwise toothed belt movement is effected by a stepping motor or a servomotor synchronized with the processing stations, which motor drives the toothed belts by toothed rollers as can be seen in the Figure for the motor  33  and the drive shaft  38 . In cases where one or more conveyor devices, such as the conveyor device  30 ′, is or are provided their toothed belts can be driven by the same motor through additional drive shafts or each conveyor device can have its own motor drive. The motor  33  is controlled by a controller  37  to perform the stepwise forward movement of the toothed belts, which control  37  is either a complete control for the entire cover manufacturing apparatus and which also controls the processing stations, or which control  37  can be a dedicated control for controlling only the conveyor device and which communicates and cooperates with a higher level control for the cover manufacturing apparatus.  
         [0028]     The motor  33  and the associated drive components for the toothed belts are arranged on a machine frame  35  which in the Figure is indicated only by its feet  35 . Drive tongues are fastened to the toothed belts, which tongues are indicated generally at  40  in  FIG. 9 , with each pair of oppositely lying drive tongues of the two toothed belts  31  and  32  forming a receiver for an object to be conveyed. By the toothed belt movement, these objects are moved by receivers formed by the driving tongues  40  along the transport path and in the direction of the illustrated arrow C from the input side of the conveyor device where the motor is located, to the output side at the end roll  36 . In the illustrated embodiment a cover  50  is provided over each of the two toothed belts and over its drive tongues, each of which covers its associated toothed belt and a portion of each drive tongue as will explained in more detail hereinafter. In the region of the processing stations these covers  50  each have a recess  52  which permits the removal of a conveyed object from the drive tongues so that the object can be lifted from the drive tongues and processed in the processing station and subsequently can be returned to the drive tongues for driving between the processing stations. As a rule no recesses  50  are provided between the processing stations so that a lifting of the objects from the drive tongues is blocked by the cover  50 . Additionally or in place of the blocking of the lifting by way of the cover  50  the drive tongues can also be designed to be magnetic, which likewise hinders a lifting of the objects during the advancement steps, if the objects are at least partially or entirely made from a magnetically attracted material.  
         [0029]     It is preferred that the lateral spacing of the toothed belts  31  and  32  from one another is adjustable so that thereby the spacing of the opposed driving tongues  40  on the two toothed belts is adjustable to adapt to the conveyor device to different sizes of objects. For this, in the conveyor device transverse connectors  58  can be provided which permit a simple adjustment of the spacing of the toothed belts from one another. Correspondingly the drive shaft or axle  38  is designed to permit this spacing adjustment. The spacings of the drive tongues  40  on each toothed belt are given by the number and even distribution of the tongues and their fasteners on the toothed belts. This spacing can preferably be changed for the accommodation of the size of the objects in that the toothed belts are exchanged for a set of other toothed belts with a different spacing, one from the other, of the drive tongues which are fastened to it. In this way by adjusting the spacing of the toothed belts relative to one another and by the substitution of toothed belts with differently spaced drive tongues the desired size of receiving areas to accommodate the objects is achieved. In this way a change over of all drive tongues for different sizes of objects can take place simultaneously and in a simple and fast manner.  
         [0030]      FIGS. 10 and 11  show pictorially sections of the toothed belts  31  and  32  having differently arranged driving tongues thereon, which driving tongues are shown generally at  40  and individually as the drive tongues  41  and  42  on the drive belt  32  and as drive tongues  43  and  44  on the toothed belt  31 . The  FIGS. 10 and 11  therefore show how an adaptation, by spacing adjustment of the toothed belts relative to one another and by an exchange of the toothed belts with differently spaced driving tongues, can be made for different cover shapes.  
         [0031]     According to the size and shape of the objects the adaptation can occur either only by adjustment of the spacing of the toothed belts relative to one another, or only by an exchange of toothed belts or by a combination of these methods. The drive tongues  41  to  44  in any event form a support for an object, on which support an object lies. As is visible from these figures, each supported object is accessible from below and from above the support by way of the arrangement of the drive tongues and the aligning of an object on the drive tongues, and the object can be removed from the support  46  provided by the drive tongues and can again be replaced onto such support. The drive tongues further have engagement surfaces  48  which extend upwardly from the support surfaces  46  and which form lateral movement limits for the object. In regard to this it is preferred that the engagement surfaces  44  are essentially flat planar surfaces and are not curved surfaces suiting the shape of the object. By the adjustability of the toothed belts relative to one another and by the possible toothed belt exchange the involved object can be essentially tangentially engaged by the engagement surfaces  48 , which is possible for different object shapes because of the flat design of the surfaces  48 . Therefore with the flat, non-shape matching design of the engagement surfaces  48  there results a desirable larger adjustment range with the same drive tongues and a corresponding smaller expense since the drive tongues need not be made to be form-fitting.  
         [0032]     The drive tongues  41  to  44  are fastened onto the belts  31  and  32  in a known way whereby at least a part of the associated tooth of the belt is removed and replaced by a fastening element which is threadably connected with the drive tongue. This fastening method is well known to the person skilled in the art and is not further illustrated here. Of course all other possibilities for the fastening of the drive tongues to the toothed belts can be used including, for example, adhesive fastening means.  
         [0033]     It can further be seen that in the preferred embodiment each of the drive tongues in the region of its drive belt has a guide which in the illustrated example is a grooved type guide in the form of the illustrated basic groove  62  and two groove side pieces  60  and  61 . In  FIG. 12  it is seen how the groove of the drive tongue receives a strip extending into it from above for guiding the drive tongue and which guiding of the drive tongue is effective to keep the toothed from belt swinging or tipping out of the conveying plane or the plane of the upper surface of the toothed belts. Such a guiding increases the immunity to vibration at high stepping rates of drive of the conveyor device and considerably improves the lifting and replacement of the conveyed objects at the processing stations from and to the drive tongues. The guiding can naturally also be arranged laterally of the drive tongues or lateral and overhead guiding can be combined, or several guides can be arranged above and/or laterally.  FIG. 12  shows that the strip  53  is a part of the already mentioned cover strip  50 . This is a preferred embodiment but the guide can also be formed by some part other than the cover strip  50 .  
         [0034]      FIG. 12  also shows how an object lying on a drive tongue  42  is secured against a lifting from the guide tongue along the conveyor path by a projection  51  covering and extending over the object in the region of the drive tongue. This is an example of a preferred mechanical securement against lifting, which here is formed by the stationary element  51 . Other possible mechanical lift preventing devices could be provided which are movable with the drive tongues and which are moveable so that in the region of the processing stations they can be moved to freeing positions relative to the carried object. The illustrated stationary mechanical lift preventor  51  is however a very simple and robust design. In  FIG. 13  it is seen how in this design in the vicinity of a processing station, or as illustrated in the vicinity of the stack from which the objects  20  are individually delivered to the conveyor device, a recess  52  is provided in the projection  51  so that at this spot a lifting and replacement of the object from and onto the drive tongue is plausible. One such recess is therefore provided at each processing station at which a lifting and replacement of the conveyed object is to take place. Instead of or in addition to the mechanical lift preventor  51 , the drive tongues can also be magnetically designed so that in moving along the conveyor path the conveyed objects are magnetically held in place. The magnetic force is in this case naturally chosen to be only large enough so that at the processing stations a lifting of the objects by the processing stations is possible. The stabilization of the drive tongues by the described guides facilitates the lifting and the replacement of the objects at the processing stations.  
         [0035]      FIG. 14  shows the end of the conveyor device, where again the same reference numbers indicate the same elements. From this it is seen how at the end of the toothed belts the drive tongues move downwardly at the end rolls  36 ,  36 ′ and release the carried object which is then carried away by a chute  57 . In the Figure the illustrated object  20  is again a cover ring and is not a finished cover, which has been done only to improve the drawing. Visible again are the cover strips  50  on which are arranged the mechanical lift preventors  51  and the guide strips  53  for the drive tongues.  
         [0036]      FIG. 15  shows an embodiment in which one of the two toothed belts is replaced by a support means  70  onto which an object  20  lies and against which the object is abutted. The support means  70  can be a stationary rail along which an object slides as it is moved by the drive tongues  43  and  44 . Also with the support means or rail, preferably a boundary element is provided which hinders a lifting of a cover during its transport. The support means  70  can also be a moveable support means, for example again a toothed belt (without drive tongues) on which the object is supported and against which it is abutted and which moves at the same speed as the object.  
         [0037]     While in the present application preferred embodiments of the invention have been described, it is to be understood that the invention is not limited to these embodiments and that the invention can be carried out in other ways while keeping within the boundaries of the following claims.