Abstract:
A linear stream of articles is conveyed to a processing station, a first one of said articles positioned in front of and in physical contact with a second one of said articles and the second one of said articles positioned in front of and in physical contact with a third one of said articles. A motor-driven rotary star wheel moves one-by-one said articles from a conveyor to a downstream processing station and is assisted in separating adjacent articles by a passive star wheel with a plurality of contoured arms separated by concave pockets. The passive star wheel receives one-by-one said articles in adjacent pockets and the contoured arms of the passive star wheel separate each article from the next following article. A guide section causes each article being separated to more along a generally tangential path relative to both star wheels as they rotate.

Description:
FIELD OF THE INVENTION 
   This invention relates to machines for labeling containers and in particular to a method and structure for separating each container in a line of containers being processed (such as by being labeled) so that each container can be separately processed. 
   INTRODUCTION 
   On a typical container production line (such as a line that uses a machine for inspecting or labeling containers) containers usually reach the packaging machine in a single file line touching each other. For processing them (applying labels, or inspecting them, or other functions) containers must be separated from each other by at least the processing distance. This task is usually accomplished by a variable pitch feed screw or by a star wheel system (as described in U.S. Pat. No. 5,772,001, for example). The objective is to maintain a constant speed of moving the containers in a single file along the longitudinal axis of the infeed conveyor but at the same time, to separate each container from contact with the next following container before the container is further processed. The star wheel system described in U.S. Pat. No. 5,772,001 accomplishes this task but the use of this system for handling small diameter containers or for handling containers which are deformable is limited. U.S. Pat. No. 5,772,001 is hereby in its entirety incorporated by reference into this specification. 
   One purpose of this invention is to provide a better functioning star wheel system which eliminates the commonly-used feed screw. Such a system would enable simple handling of all containers at a higher speed than is possible with current systems. 
   DESCRIPTION 
   In accordance with this invention, a system is provided which includes a constant velocity star wheel which is driven at a rate required by the machine function in combination with a free wheeling passive flow star inserted in a moving single file of containers. In one embodiment of this invention, appropriate outside and inside container guides are provided to control the path of the containers&#39; movement. The speed of the containers in the axis of the conveyor is determined by the profile of the constant velocity star wheel, the profile of the passive flow star wheel and the shape of the containers&#39; guides. To prevent loading of more than one container in the pocket of the constant velocity star wheel, the passive flow star effectively creates a barrier between two directly adjacent containers coming from the conveyor. The passive flow star can, during forward motion of the containers&#39;, create a gap between two directly adjacent containers as the tip of the constant velocity star wheel is advancing to separate each container from the single file of containers. This way even small containers or containers which are experiencing deformation from line pressure can be effectively separated and delivered with the required spacing to the machine for further processing. At the same time, because of mutual geometric relations among involved parts and containers, any speed profile required for each container as it is progressing on the conveyor can be achieved by properly shaping the profile of the constant velocity star wheel. 
   This invention will be more fully understood in view of the following detailed description taken together with the drawings. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIGS. 1   a ,  1   b  and  1   c  show plan views of structure in accordance with one embodiment of this invention at three different times during the operation of this structure to separate a lead container from direct contact with the next following container as the two containers travel along a conveyor, the separation being in preparation for transferring the lead container to, for example, a labeling station which is part of a labeling machine. 
   

   DETAILED DESCRIPTION 
   The following description is illustrative only and not limiting. Other embodiments of this invention will be obvious in view of this description to those skilled in the container processing and labeling arts. 
     FIG. 1   a  shows in plan view structure  100  of one embodiment of this invention as used to position containers for the placement of labels on the containers. If desired, this embodiment can be used to position containers for other processing steps such as inspection or for loading containers on to the platform of carousel style machines such as filler machines, inspection machines, labeling machines, and similar machines containing rotating platforms for holding containers for further processing functions. In  FIG. 1   a , constant velocity star wheel  101  is driven by a motor (not shown) in a well known manner. Star wheel  101  has a plurality of contoured arms such as arms  102 - 1  to  102 - 7  (although other numbers of contoured arms can be used on the constant velocity star wheel  101  if desired). Star wheel  101  in one embodiment rotates at a constant velocity when the conveyor (not shown) brings the containers to star wheel  101  at a constant velocity. 
   In the embodiment shown, a plurality of articles such as containers  1 ,  2  and  3 , are being moved in a substantially continuous stream in preparation in this embodiment for the application of labels to the containers. Star wheel  101 , having a plurality of contoured arms  102 - 1  to  102 - 7 , is rotated counterclockwise in the direction of arrow A such that the contoured arms  102  each individually move a corresponding article from the conveyor to a station downstream where an operation, such as the placing of a label on the container or inspection of the container, can be carried out. Each of the contoured arms  102  has a leading convex surface  104  (sometimes called a “cam surface”) and a leading concave surface  103  which defines a pocket shaped to partially receive one of the containers. The cam surface  104 - i  (such as cam surface  104 - 2  associated with contoured arm  102 - 2  on star wheel  101 ) of the corresponding contoured arm  102 - i  (where “i” is an integer given by 1≦i≦I where “I” is the maximum number of contoured arms on the star wheel  101 ) guides a container into the concave pocket  103 -( i+ 1) defined by the leading surface of the following adjacent arm  103 -( i+ 1). The leading surface  103 -( i+ 1) of the next-following adjacent arm  103 -( i+ 1) moves the container toward the downstream station. At this station a segment of material may be applied in a well-known manner to the exterior surface of the container. 
   The feed apparatus of this invention, also includes passive flow star wheel  107  which is rotated by the force created by a container being pressed against one of the contoured arms  108  of the star wheel  107 . Shown in  FIG. 1   a  are contoured arms  108 - 1  to  108 - 6  on passive star wheel  107 . Of course other numbers of contoured arms  108  can be used on passive star wheel  107  depending on the requirements of the system  100 . Each contoured arm  108  is separated from the two adjacent contoured arms by a concave pocket. For example, contoured arm  108 - 3  is separated from contoured arm  108 - 2  by concave pocket  109 - 3  and is separated from contoured arm  108 - 4  by concave pocket  109 - 4 . 
   During operation, containers such as containers  1 ,  2  and  3  shown in  FIG. 1   a  are brought to the constant velocity star wheel  101  by a conveyor, for example. A container identified as container  111  is shown as having been separated from the previously following but directly-adjacent container  112  by the cam surface  104 - 2  of contoured arm  102 - 2  and then embraced by concave pocket  103 - 3  associated with the next-following contoured arm  102 - 3 . As star wheel  101  rotates counterclockwise, container  111  is moved away from the directly-following container  112 . This movement is assisted by passive star wheel  107 . Thus container  111  has rested in concave pocket  109 - 3  of passive star wheel  107  as container  111  is moved away from container  112  by star wheel  101 . However, contoured arm  108 - 2  has inserted itself between container  111  and container  112  and thus has forcibly separated these two containers from each other. Passive star wheel  107  is rotated clockwise in the direction of arrow B by the constant velocity star wheel  101  which applies a pushing force to container  111 , for example, thereby moving container  111  away from container  112  and at the same time, because of the placement of container  111  in concave pocket  109 - 3  of passive star wheel  107 , causing star wheel  107  to rotate in the direction of arrow B. 
   Thus star wheel  107  assists in the separation of directly adjacent containers being brought to the downstream workstation to be processed by passively being rotated and while being rotated inserting a contoured arm  108  between directly adjacent containers. 
     FIG. 1   b  shows the structure after container  111  has been successfully sent to the processing station and container  112  has been separated from its next following container  113  in preparation for container  112  to be sent to the processing station. Note that container  112  has been reached by and is thus in contact with the concave surface  103 - 4  associated with contoured arm  102 - 4  on star wheel  101 . Note further that container  112  is also being separated from container  113  by the insertion of contoured arm  108 - 1  on passive star wheel  107  between container  112  and container  113 . Container  112  is being moved out of concave pocket  108 - 2  by the counterclockwise rotation of star wheel  101 . Contoured arm  108 - 2  is dropping away from container  112  to allow container  112  to move along the interior arcuate surface  106   a  of outside container guide  106  Interior surface  106   a  of guide  106  is arcuate (concave facing the containers) to guide each container to the work station (not shown) for further processing. Guide  106  works together with inside container guide  105  and in particular with the inside surface  105   a  thereof, to ensure that the containers being transferred to the downstream work station are properly constrained so that the can be separated by the two star wheels  101  and  107  working together as described herein. 
     FIG. 1   c  shows the system when container  112  has been transferred to the downstream processing station for further processing and container  113  is just starting to be separated from the next following container  114 . Arm  108 - 6  of passive star wheel  107  is being inserted between containers  113  and  114  thereby assisting in the separation of these two containers. Concave pocket  103 - 5  is about to embrace container  113  such that cam surface  104 - 5  associated with contoured arm  102 - 5  will guide container  114  together with the interior shaped surfaces  105   a  and  106   a  of guides  105  and  106 . Contoured arm  108 - 6  assists in separating container  113  from container  114  as passive star wheel  107  rotates in response to a pushing force transmitted by container  113  from contoured arm  102 - 5  of star wheel  101  driven by a motor (not shown). 
   The result of this structure is the ability to separate in preparation for further processing of linearly advancing containers in direct contact with each other thereby to allow the rapid and smooth processing of the separated containers at a high speed. Typical processing rates associated with this system when used for applying labels to containers are in the range of 300 to 1200 containers per minute A benefit of this invention is that containers are separated from each other without any abrupt change in speed and direction (i.e. without an abrupt change in the speed vector). Another way of saying this is that in the same time line speed is not changing. This prevents line vibration and overloading of involved mechanical parts and thus prevents damages to containers. This process is similar to the use of a feed screw with progressive pitch to separate containers but has the advantage that only one passive star wheel is required whereas in the case that containers are tall or unstable, two feed screws, one above the other must be used. The starwheel system of this invention is accomplishing the same task with a much simpler structure while maintaining each container in its vertical position and also overcoming line pressure which is a problem for the feed screw system. The starwheel system of this invention is using line pressure for its benefit and therefore line pressure does not present a problem during system operation.