Abstract:
A can seaming apparatus and methods of forming a seam on a can and lid assembly is disclosed. The apparatus comprises one or more seaming arms pivotably attached to a shaft, a seam roller attached to one end of each seaming arm and a cam system. The cam system comprises one or more cams associated with the end of each seaming arm opposite the seam roller. Force is transferred to each seaming arm through rotation of the one or more cams. The seaming arm then pivots and moves the associated roller into a seaming area of a can and lid assembly to create a seam.

Description:
TECHNICAL FIELD 
       [0001]    The present disclosure is directed to systems and methods for the production of seams to seal lids onto cans, particularly seaming metal lids and cans in the food and beverage industries. 
       BACKGROUND 
       [0002]    A variety of can seaming apparatus are presently available for seaming lids onto metal cans in the food and beverage industries. Particularly for smaller cans with smaller lids, pneumatic sealing devices are preferable in terms of cost reduction and setup time. However, one existing difficulty in devices using air pressure to drive pivoting arms equipped with seam rollers into a can seaming area is in maintaining the high accuracy necessary to drive the roller into the correct position at the seaming area to produce a sufficient seam. 
         [0003]    Typically, an air cylinder drives the seam roller into the seaming area. However, maintaining a consistent dimensional deformation throughout the seaming area is difficult to achieve with air cylinders in conventional designs. Existing methods use a sequence of two seam rollers to form the lips of the lid and the can into the required seal. Low pressure in the air system driving the seam rollers or an inadequate dwell time in the seaming process lead to discontinuity in the seam area. This causes dimensional variations in the seam area. Additionally, if the seam producing rollers travel too far into the seam forming area or not far enough, an inadequate seam is formed. These inaccuracies frequently lead to leakage and contamination of contents within the can. Such cans are not acceptable for further processing or sale, which leads to inefficiencies in the canning process and production of canned foods and beverages. 
         [0004]    The repeatable seam apparatus disclosed herein is intended to overcome one or more of the problems discussed above. 
       SUMMARY OF THE EMBODIMENTS 
       [0005]    One embodiment disclosed herein is a can seaming apparatus that includes a seaming arm pivotably attached to a shaft of the can seaming device. A seam roller is attached to one end of the seaming arm, and a cam system is attached to the other end of the seaming arm distal to the seam roller. 
         [0006]    The cam system of the can seaming apparatus may include a rotating cam, a cam follower and an actuator. The actuator may rotate the cam about an axis, with the rotating cam providing a force on the cam follower that is in mechanical contact with the perimeter of the rotating cam. The cam follower may be operatively attached to an end of the seaming arm distal the seam roller. The force provided to the cam follower may be transferred to the seaming arm through direct contact, and therefore pivoting the seaming arm about the shaft of the can seaming device. The pivot force provided at one end of the seaming arm may swing the other end of the seaming arm, containing the seam roller, into a seaming area of a can and lid assembly. 
         [0007]    In an embodiment which features an actuator in the cam system, the actuator may be a pneumatic actuation device. In other embodiments, the actuator may be an electric motor or a programmable controller. 
         [0008]    Similarly, the cam follower may be an eccentric cam follower, thus allowing for fine tune adjustments to the cam system driving the seaming arms and seam rollers of the can producing apparatus. This may allow for smooth and repeatable can seaming operation. 
         [0009]    Furthermore, the cam system may include a separate single-lobed rotating cam for each actuation device. In some embodiments, the can seaming apparatus may include a plurality of seam rollers. In this representative embodiment, the can seaming apparatus may further include multiple seaming arms. As such, the cam system of the can seaming apparatus might include a rotating cam with two or more lobes. The number of lobes may correspond to the number of seam rollers in operation of the can seaming apparatus. 
         [0010]    The can seaming apparatus may include a height adjustment device attached to the seaming arm. This may provide for adjustment of the vertical positioning of the seam roller. In some cases, this height adjustment device may be a manually turnable knob, where turning the knob in either direction may cause the seam roller to be positioned higher or lower on its vertical axis. The height of the seam roller may be specified according to industry standards for producing acceptable can seams. The height adjustment device may allow for easy adjusting, and therefore repeatable fine tune adjustments of the positioning of the seam roller into a proper seam area of the can and lid assembly. This particular embodiment may contribute to producing repeatable and highly accurate can seams with the can seaming apparatus. The cam seaming device may further include a can lifting device to lift a can and lid assembly into contact with the seaming chuck. 
         [0011]    It may be desirable for specific embodiments that the bearing of the rotating cam is aligned with the rotational axis of the can and lid assembly. In other embodiments, the bearing of the cam may rotate at an axis that is offset from the rotational axis of the can and lid assembly. 
         [0012]    Another embodiment disclosed herein is a method of producing a seam on a can and lid assembly. The method includes providing a seam roller that is attached to one end of a seaming arm. The seaming arm may be pivotably secured to a shaft. A cam system may be provided, and may include a rotating cam that is mechanically associated with a cam follower and an actuator. The cam system may be operatively associated with a second end of the seaming arm that is distal to the first end containing the seam roller. The actuator may actuate the cam system to drive the rotating cam, which may provide a sliding force on the cam follower that is in contact with the perimeter of the rotating cam. This contact may transfer a force from the rotating cam to the second end of the seaming arm, which may cause a repeatable swinging motion of the seaming arm about the shaft, and therefore engage the seam roller into contact with the can and lid assembly. 
         [0013]    As used herein, a means for actuating the cam system may include pneumatic actuation means. Alternatively, the actuating means include means for an electric motor or means for programmable controls. 
         [0014]    The method may further include adjusting the cam system by selecting a specific eccentric cam and cam follower. This may allow for producing a highly accurate and repeatable can seam. 
         [0015]    In other embodiments, the method may include driving a single lobe rotating cam of the cam system with an actuator. Alternatively, the method may include driving a multiple lobe rotating cam with an actuator. 
         [0016]    A height adjustment device may allow for fine tuning of the vertical height of the seam roller with respect to the can and lid assembly. Such positioning of the seam roller may be specified by industry standards, and furthermore may be easily adjusted with the height adjustment device, therefore allowing the user to produce accurate and repeatable can seams. 
         [0017]    The method may further include rotating the cam around the rotational axis of the can and lid assembly. In another embodiment, the method may include rotating the cam at an axis that is offset from the rotational axis of the can and lid assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a perspective view of a can seaming apparatus as disclosed herein. 
           [0019]      FIG. 2  is a perspective view of several components of a can seaming apparatus from an upper point of view. 
           [0020]      FIG. 3  is a perspective view of a seaming area for a can and lid assembly and a can seaming apparatus. 
           [0021]      FIG. 4  is a perspective view of a seaming area for a can and lid assembly and a can seaming apparatus. 
           [0022]      FIG. 5  is a perspective view of the engagement of a seam roller with a seaming area of a can and lid assembly. 
           [0023]      FIG. 6  is a perspective view of a cam system that drives components of the can seaming apparatus of  FIG. 2 . 
           [0024]      FIG. 7  is a perspective view of several components of a can seaming apparatus from a lower point of view. 
           [0025]      FIG. 8  is an additional view of a cam system of a can seaming apparatus from an upper and rear point of view. 
           [0026]      FIG. 9  is a front plan view of a can seaming apparatus and elevation device. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Unless otherwise indicated, all numbers expressing quantities of ingredients, dimensions, reaction conditions and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about”. 
         [0028]    In this application and the claims, the use of the singular includes the plural unless specifically stated otherwise. In addition, use of “or” means “and/or” unless stated otherwise. Moreover, the use of the term “including”, as well as other forms, such as “includes” and “included”, is not limiting. Also, terms such as “element” or “component” encompass both elements and components comprising one unit and elements and components that comprise more than one unit unless specifically stated otherwise. 
         [0029]      FIG. 1  illustrates one embodiment of a can seaming apparatus  100 . The  FIG. 1  embodiment features a pneumatically actuated cam that can be deployed against a pivoting arm equipped with a specialized roller to repeatedly produce a pressure tight seam in a can. Particularly, the disclosed can seam producing device uses both a highly accurate cam system and a linearly actuated slide, pneumatically driven or otherwise, to deploy the cams. The various embodiments feature a metal cam with an adjustable cam follower in order to achieve precise dimensional control in the seaming process. An adjustment feature on the cam follower enables an operator to finely tune the engagement of both seaming rollers, producing a controllable seam between the can and the lid. The disclosed systems can be retrofitted on existing pneumatic only driven can sealers. The described systems can also operate as a standalone can sealing device. 
         [0030]      FIG. 2  is a perspective view from an upper vantage point of the seam producing device  100 . In use, a can and lid assembly  104  to be seamed is brought into contact with a seaming chuck  103 . The seaming chuck  103  includes apparatus configured to secure the can and lid assembly  104  in an operative position with respect to the seam producing device  100 . A motor  111  spins a shaft connected to the seaming chuck  103  at a sufficient speed to accomplish a selected number of complete revolutions in a given time frame, as required for the fabrication of an acceptable seam. The can/lid assembly  104  is held in place by the seaming chuck  103  and rotates with the motor-driven shaft of the seaming chuck  103 . As both the can/lid assembly  104  and seaming chuck  103  are rotating, seam rollers  101  and  102  are brought into the area of the can/lid assembly  104  where a seam is to be formed. Formation of the can seam is accomplished in two operations. Separate rollers are therefore required. In the first operation the first seam roller engages the lip of the can and the curled outer section of the can lid and initiates the seaming process by forming the can and lid into a mutually engaged curl. The second operation involves a second roller with a different form that finishes a double envelopment seam by forming the results of the first operation into a tightly compressed band with overlapping metal from both the can and the lid. When properly aligned, the above processes form a permanent hermetic seal. 
         [0031]    Height adjustment devices  107 ,  108  are threaded and fit into a likewise threaded portion of the seaming arms  105 ,  106 . The height adjustment devices  107 ,  108  provide for the height of the seam rollers  101 ,  102  to be very accurately oriented vertically with respect to the chuck  103  and can/lid assembly  104 . The seaming arms  105 , 106  can be rotated about pivots  114 ,  115  (hidden). Rotary actuators  109 ,  110  are located at the far end of the seaming arms  105 ,  106  from the seam rollers  101 ,  102 . The rotary actuators  109 ,  110 , in conjunction with certain cam embodiments described in detail below, drive the seaming arms  105 ,  106  into and out of an operative position. 
         [0032]    In one embodiment, a single cam rotating on its own bearing and having a cam axis coincident with the axis of the can/lid assembly  104  and the seaming chuck  103 , or offset a given distance from this axis, can actuate the seam rollers  101 ,  102  to provide an accurate seam. In a single cam embodiment the cam will have two or more lobes corresponding to the number of seam rollers  101 ,  102 . For example,  FIG. 3  illustrates the location and position of the driving cam  121  in a single cam embodiment. This cam has a center of rotation located coincident with the center of rotation of the seaming chuck  103 . 
         [0033]    In other embodiments, a separate cam with a single lobe may be provided for each separate rotary actuator  109 ,  110 . In this alternative embodiment, each separate cam can be mounted on its own separate bearing. In either embodiment, the rotating cam or cam system is driven separately from the can rotating system and can be sequenced on command. The cam or cam system can be driven by a pneumatic device, by an electric motor device, or another commonly used actuation method. The cam or cam system may be controlled, for example, with commands from a programmable controller. As described in detail below, adjustable cam followers  117 ,  118  for each of the arms carrying seaming rollers  101 ,  102  allow an operator to precisely adjust the resulting seam to a given specification. 
         [0034]    In the case of a pneumatically actuated cam, the cam can be deployed against a pivoting arm equipped with a specialized roller to repeatedly produce a pressure tight seal in a can. An air pressure driven slide can be actuated to bring a shaped cam into contact with a rolling element mounted on a swiveling arm. On the opposite end of the arm, a specially constructed seam roller  101 , 102  is brought into a fixed distance from the edge of the can/lid interface. 
         [0035]      FIG. 4  is a perspective view of the seaming area. The seaming chuck  103  is attached to a shaft  113  driven by the motor  111 . Seam roller  101  performs the first of two operations required to fabricate a proper seam. The seam roller  101  is brought into an accurate and repeatable position in relation to the seam area  112  of the can/lid assembly  104 . Accuracy in positioning the seam roller  101  at a fixed distance from the edge of the can/lid assembly  104  is critical to the formation of a proper seam. Upon completion of the first operation, the initial seam roller  101  is retracted and the second seam roller  102  is brought into an accurate and repeatable position in relation to the seam area  112 . The second seam roller has a different special construction to produce the final formation of the seam. The height adjustment devices  107 ,  108  control the position of their respective vertically aligned seam rollers  101 ,  102 . Both seam rollers  101 ,  102  require exact dimensional control. 
         [0036]      FIG. 5  illustrates the engagement of seam roller  101  into seaming area  112 . The seaming chuck  103  and can/lid assembly  104  rotate together for this first operation by seam roller  101 . The seam roller  102  is disengaged, as shown by the gap between the seam roller  102  and the lip of the can/lid assembly  104 . 
         [0037]      FIG. 6  illustrates the cam system that drives the seaming arms  105 ,  106  in a rotating fashion to bring the seam rollers  101 , 102  into the desired accurate and repeatable position. In one embodiment, rotary actuators  109 ,  110  drive the driving cams  116 ,  119  in a continuous rotation. The cam followers  117 ,  118  in contact with the rotating driving cams  116 ,  119  transfer the rotary motion imparted to the cams  116 ,  119  by the rotary actuators  109 ,  110  into linear motion by pushing the seaming arms  105 , 106  about pivots  114 ,  115 . Consequently, the seaming arms  105 ,  106  attached to the seam rollers  101 ,  102  push the seam rollers  101 ,  102  into the rotating seaming area  112 . The seaming action is accomplished by deforming the can and lid interface in a controlled manner. Gross adjustment of the seam rollers  101 ,  102  is accomplished by loosening the rotary actuators  109 ,  110  and moving them in a lateral mode, thereby increasing or decreasing the relative position between seam rollers  101 ,  102  and the seaming area. Once gross adjustment is completed, the rotary actuators  109 ,  110  are re-tightened. The cam followers  117 ,  118  have eccentric base mounts, allowing for fine adjustment of the relative position between the seam rollers  101 , 102  and the seaming area  112 . Such adjustments are made in anticipation of conforming to well-established industry parameters. 
         [0038]      FIG. 7  illustrates a perspective view from the lower vantage point of the seam producing apparatus, showing the driving cam  116  and corresponding cam follower  117  and the driving cam  119  and corresponding cam follower  118 . 
         [0039]      FIG. 8  provides an additional view of the driving cam  116  and cam follower  117  connected to the seaming arm  106 . In operation, the driving cam  116  rotates and the rotation is traced by the cam follower  117 . With the cam follower  117  attached to the seaming arm  106 , the tracing action causes the seaming arm  106  to pivot about the pivot  115 . This repeatable and accurate action places a first seam roller  101  (not shown on  FIG. 8 ) into contact with the seaming area  112  of the can/lid assembly  104 . The second seam roller  102  is then put in contact with the seaming area  112  of the can/lid assembly  104  to complete a seam. The seaming arms  105 ,  106  may be provided to have carefully selected lengths, so that force is multiplied at the seam rollers  101 ,  102 , thereby lessening radial forces on the cam followers  117 ,  118  and the driving cams  116 ,  119 . 
         [0040]    The adjustability of the driving cams  116 ,  119  attached to the rotary actuators  109 ,  110  in combination with the eccentric based cam followers  118 ,  117  make the final specifications of the produced seam controllable within the range of 0.001 inch, according to some embodiments. In other embodiments, the can seam is repeatable to within 0.003 inch. 
         [0041]    As shown in  FIG. 9 , the can seamer  100  may be implemented in conjunction with a can elevation device that raises a can/lid assembly  104  from the conveyor surface to engage the seaming chuck  103 . The filled can/lid assembly  104  is required to rotate in concert with the rotating seaming chuck  103 . The  FIG. 9  can elevation device embodiment features a table  120  that engages the bottom of the filled can/lid assembly  104 . Contained within the table  120  is a bearing (hidden) that allows the table  120  to follow the rotation of the seaming chuck  103 . The can/lid assembly  104  located on the table  120  is raised by a pneumatic cylinder  121 , or other lifting means. The pneumatic cylinder  121  is configured to bring the filled can/lid assembly  104  into engagement with the seaming chuck  103  prior to the full extension of the pneumatic cylinder. An externally controlled pressure source then allows the operator to produce an accurate axial force engaging the filled can/lid assembly  104  with the seaming chuck  103  which is useful for the accurate reproduction of the formed seam.