WO1998010264A1

WO1998010264A1 - Method and apparatus for measuring container seams

Info

Publication number: WO1998010264A1
Application number: PCT/US1997/014746
Authority: WO
Inventors: Bryan W. Broemson
Original assignee: Applied Statistics, Inc.
Priority date: 1996-08-23
Filing date: 1997-08-21
Publication date: 1998-03-12
Also published as: AU4082097A

Abstract

A method and apparatus for automatically measuring seam characteristics of a container seam having a reference surface (32) and one or more of a seam height measuring mechanism (58), a seam width measuring mechanism (26) and a countersink depth measuring mechanism (30).

Description

Title: Method And Apparatus For Measuring Container Seams

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to a method and apparatus for measuring container seams, and more particularly to a method and apparatus

for measuring seam characteristics of a container seam including characteristics such as seam thickness, seam height and countersink depth. 2. Description of the Prior Art

Seamed containers are commonly used as beverage cans, food containers and the like in which a container wall is connected with a container top and /or bottom by a seam. Seam dimensions which are most important for the integrity of the seam include the seam thickness defined by the distance

between the seam inner wall and the seam outer wall, the seam height defined by the distance between the seam top edge and the seam bottom edge and the countersink depth defined by the distance between the seam top edge and the countersink surface of the container. Any deviations from nominal with respect

to these characteristics indicates that the seam integrity might have been compromised.

Seam integrity is important for two reasons. First, any leaks or rifts may cause product contamination. For example, contaminates from the outside

environment may come into the can and affect their product contained therein. Further, the internal environment may escape, resulting in a high permeation 51 rate. A common example of this is in the beverage industry where a high permeation rate would result in CC> escaping and the product becoming "flat".

Two methods are currently in use for measuring seam thickness.

One involves manual use of calipers with dial indicator read-out and a second

involves a destructive test methodology which involves cutting a slot out of a seam area of a can and using an optical comparator to measure the distance between the seam inner and outer walls. The seam height is currently measured

manually using calipers with a dial indicator read-out. The countersink depth is measured using a depth gauge with dial indicator read-out. Various disadvantages and limitations exist with respect to current measuring techniques. First, devices such as calipers and depth gauges are inherently unreliable for specifications that have a degree of accuracy less than plus/minus 0.010. When measuring seam thickness or seam height with calipers, the results can be significantly influenced by the operator since it is

relatively easy to flex the jaws of a caliper so that the readings change by as much

as 0.005 inches. Similarly, the operator can alter readings on a depth gauge by holding the gauge at slightly varying angles relative to the surface being measured and by varying the downward pressure of the gauge against the

container top. Measurements of seam thickness using an optical comparator is a

destructive test. This works against increasing the sampling frequency and also results in lost product. Further, the calipers and depth gauge measurements as well as the measurements done utilizing optical comparative technology are

time consuming. Still further, the cutting of the seams to facilitate b measurements via optical comparative technology tends to distort the dimensions and thus reduces accuracy of the measurements.

Accordingly, there is a need in the art for an improved method and apparatus for measuring container seams and in particular a method and apparatus for measuring seam characteristics of container seams which is fast, accurate and is not destructive.

SUMMARY OF THE INVENTION

In contrast to the prior art, the present invention relates to a method and apparatus capable of accurately, repeatably, and with high resolution,

measuring the seal integrity of container seams. More specifically, the present invention is capable of measuring the seam thickness, seam height and countersink depth of a container seam automatically, simultaneously and at multiple locations, with high accuracy and without destroying the container.

Further, the measurements can be made electronically; thus facilitating continuous measurements of a particular characteristic and electronic storage of the data for archival or analytical purposes.

In general, the apparatus includes a datum or reference plate that positions the container or beverage can during loading and when lowered makes contact with a datum riser block on which the beverage can is held stationary by its own weight. A handle assembly or other automated means locates and locks

the datum plate in one of two positions. In an upward position the apparatus assures that the seam height measuring assembly and other sensor components are clear for placement of the beverage can in and out of the gauge. When the handle and datum plate are moved down, the datum plate is firmly seated against the datum riser block. This establishes the position of the can for measurements.

A roller affixed to the base of the datum plate moves the seam

width measuring assembly horizontally according to the vertical position of the handle and thus the datum plate. When the handle is up the roller which is affixed to the base of the datum plate holds the seam height measuring assembly

away from the beverage can. The horizontal position of the chisel contact tip is guided by the vertical travel of the roller and the profile of the seam height sensor housing. Moving the handle down causes the seam height assembly to move toward the can so that the chisel contact tip makes contact with the side of the can body. The chisel contact tip is spring loaded downwardly. A lever connected to the seam height measuring assembly is spring loaded and has a notch that catches a pin located within the chisel contact tip which prevents the chisel contact tip from dropping downwardly. The purpose of the lever is that it

prevents the chisel contact tip from dropping below the seam of the beverage can during lowering of the beverage can for measurements. When the roller makes contact with a lever surface, the chisel contact tip is released by the lever which

lets the chisel contact tip make contact with the edge of the beverage can lid. When the datum plate is seated upon the datum riser block the seam height feature is properly positioned for the measurement to be taken. When the beverage can is raised, a tab moveable with the datum plate catches the base of the chisel contact tip and assures that each time the datum plate is returned to the upper position, the chisel contact tip will be raised up and locked in the notch of the lever.

To measure the countersink depth sensor is affixed to the datum riser block. A countersink contact tip associated with the sensor extends through

a clearance hole in the datum plate to make contact on the radius at the root of the countersink feature. The countersink measurement is done when the datum plate is seated upon the datum riser block.

The seam width measuring assembly is done with a ball contact tip and a cylinder contact tip. The ball contact tip is connected to a linear table that is spring loaded to cause the ball contact tip to make contact with the inside taper of the beverage can lid. The cylinder contact tip makes contact on the outside

radius of the can seam. The cylinder contact tip is affixed to a sensor that is

affixed to a plate mounted to the linear table. The linear table positions the ball tip contact so that the can seam edge can slide between the ball contact tip and the cylinder contact tip. The sensor measures the distance between them. The seam

width measurement is done when the datum plate is seated upon the datum riser block.

Accordingly, it is an object of the present invention to provide an automated method and apparatus for measuring seam characteristics of a

container seam.

A further object of the present invention is to provide a method and apparatus for accurately and repeatably measuring seam characteristics of a container seam including seam height, seam width and /or countersink depth. A further object of the present invention is to provide a method and apparatus for measuring seam characteristics of a container seam which is significantly faster and more accurate than prior art techniques.

A still further object of the present invention is to provide a method and apparatus for measuring seam characteristics of a container seam which does not involve destruction of the container.

Another object of the present invention is to provide a method and apparatus for measuring seam characteristics of a container seam in which multiple seam characteristics can be electronically measured simultaneously and the results stored electronically in a data base for archival or analytical purposes.

A further object of the present invention is to provide a method and apparatus for measuring a seam characteristic of a container seam electronically at multiple locations of the container simultaneously.

These and other objects of the present invention will become apparent with reference to the drawings and the description of the preferred embodiment and method.

DESCRIPTION OF THE DRAWINGS

Figure 1 is an elevational side view, partially in section, showing the apparatus of the present invention for measuring seam characteristics of a container seam.

Figure 2 is a sectional view showing the configuration of what is commonly referred to as a double seam. Figure 3 is an exploded, isometric view of a base and datum plate of the apparatus to the present invention.

Figure 4 is an isometric view of a portion of the container guide structure of the apparatus of the present invention.

Figure 5 is an isometric view of the mechanism for measuring seam height.

Figure 6 is an elevational side view of the mechanism for measuring seam height.

Figure 7 is an elevational side view, with parts in section, of the mechanism for measuring seam height.

Figure 8 is an isometric view of a support lever of the seam height measuring mechanism.

Figure 9 is an isometric view of the mechanism for measuring the seam width. Figure 10 is an elevational side view of the mechanism for

measuring the seam width.

Figure 11 is an elevational plan view of the mechanism for measuring the seam width.

Figure 12 is a view, partially in section, showing the mechanism for

measuring countersink depth as viewed along the section line 12-12 of Figure 3.

Figure 13 is an isometric view of the countersink probe tip assembly used in connection with the measurement of countersink depth.

Figure 14 is a view, partially in section, as viewed along the section

line 14-14 of Figure 12. I

Figure 15 is an isometric view of a portion of the apparatus of the present invention showing the handle assembly, with parts missing.

Figure 16 is a partial view of the handle assembly, as viewed along the section line 16-16 of Figure 15.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND METHOD

The present invention relates generally to a seam measuring apparatus and method and more particularly to an apparatus and method for measuring various seam characteristics of a container seam. The present

invention has applicability to a wide variety of container seams such as, among others, double seams which are commonly used in connection with beverage and canned food containers, flex seal seams which are commonly used in conjunction with a Mylar or PVC strip in connection with juice cans, and friction

seal seams commonly utilized in connection with the packaging of powders or the like.

The preferred embodiment of the present invention is described

with reference to an apparatus for measuring seam characteristics of a

conventional double seam of a beverage can which is illustrated in detail in Figure 2. With reference to Figure 2, a conventional double seam is used to join a container wall 10 with a container end 11. The seam is comprised of a body hook 12 comprised of an extension of the body wall 10 and an end hook 14 comprised of an extension of the container end 11. In forming the double seam shown in Figure 2, the respective ends of the wall 10 and container end 11 are bent and crimped as shown and a sealing compound 15 is disposed within the seam to seal the container. The external portion of the seam includes an inner seam wall 16 commonly referred to as a chuck wall, an outer seam wall 18 commonly referred to as a seaming wall, a top seam edge 19 commonly referred to as a seaming panel and a bottom seam edge 20. The end wall 11 of a beverage

can also commonly includes a countersink portion 21. The seam characteristics which are most important in determining seam integrity include the seam width SW defined by the distance between the inner seam wall 16 and the outer seam wall 18, the seam height SH defined by the distance between the top seam edge 19

and the bottom seam edge 20 and the countersink depth CD defined by the distance between the countersink portion 21 and the top seam edge 19.

The present invention utilizes electronic linear sensors in the

measurement process. Thus, the measurement data is electronically created and can thus be stored electronically in a data base for archival or analytical purposes. Electronic creation of the data also facilitates multiple seam characteristics being measured simultaneously and continuously and seam characteristic measurements being made at several locations around the container seam simultaneously and continuously.

With reference first to Figure 1, the seam measuring apparatus in accordance with the present invention includes a base assembly 24, a mechanism 25 for measuring the seam height, a mechanism 26 for measuring the seam width and a mechanism 28 for guiding and properly positioning the container 29 in a measuring position. The apparatus of the present invention also includes a mechanism 30, illustrated best in Figures 12 and 14, for measuring the

countersink depth. The base assembly 24 includes a centrally positioned, fixed datum riser block 31 and a fixed base plate or frame 32. The plate 32 is rigidly secured to the riser block 31 and extends laterally outwardly from the riser block 31 for supporting and securing the seam height measuring apparatus 25 and the seam

width measuring apparatus 26 in a measuring position. The base plate 32 is connected at its peripheral edge to an apparatus support in the form of side plates 34. The base assembly also includes a moveable datum plate 35 mounted on the support post 46 and adapted for vertical movement relative to the riser block 31 as described below.

In the preferred embodiment, three seam height measuring mechanisms 25, three seam width measuring mechanisms 26 and three countersink depth measuring mechanisms 30 are associated with the apparatus and positioned around the periphery of the seam to be measured. This enables

multiple measurements for each of the seam characteristics to be made simultaneously. It is recognized, however, that the benefits of the present invention can be realized using any number of measuring mechanisms, including a single measuring mechanism for measuring a single seam

characteristic.

Reference is next made to Figure 3 illustrating the details of the datum riser block 31 and the datum plate 35. The datum plate 35 is selectively

moveable between a raised, inoperative position (as shown in Figure 1) and a lowered, operative or measuring position in which the datum plate engages the top of the riser block 31. The datum plate 35 includes a container guiding ledge 39 having a sloping or beveled surface 38. The surface 38 engages an inner edge H portion of the seam and assists in guiding the container 29 into a measuring

position in which the top seam edge 19 (Figure 2) engages the locating or reference surface 36. The datum plate 35 further includes a plurality of rollers 41 mounted about its periphery via the mounting members 40. A plurality of

recessed areas 42 provide measuring access for the seam width measuring mechanism 26 as described below. The ledge 39 is provided with a plurality of access or clearance holes 44 to provide measuring access for the countersink depth measuring probe. An opening 45 is provided in the datum plate for

insertion of an alignment pin 52 (Figure 12) to prevent rotation of the datum plate 35 relative to the riser block 31.

With continuing reference to Figure 3, the riser block 31 includes a central opening 48 for housing a bearing and rod assembly for moving the datum

plate 35 and a plurality of recessed areas 49 for providing access for the rollers 41 and the seam height measuring mechanism 25 (Figure 1). A plurality of recessed areas 50, corresponding in location to the recessed areas 42, provide seam measuring access for the seam width measuring mechanism 26. An alignment pin hole 51 is aligned with the hole 45 for receiving the alignment pin 52 (Figure 12). The riser block 31 also includes a plurality of keyhole shaped openings comprising a larger hole 54, a smaller hole 53 and a section 57 joining the holes

53 and 54. These holes 53 and 54 are designed to receive a plurality of countersink depth measuring sensors and probes as shown in Figures 12 and 14. A plurality of openings 55 and corresponding set screws 138 (Figure 12) are provided for fixing the vertical position of the countersink measuring sensor 33

(Figure 12). With reference again to Figure 1, the container guide assembly 28 is

fixed to the base assembly 24 and includes a guide tube 56, a guide ring 58 and a

means in the form of a handle and rod assembly 59 for moving the datum plate 35, and thus the supported container 29, upwardly and downwardly relative to the datum riser block 31. With reference to both Figures 1 and 4, the guide tube 56 includes a generally cylindrical base 60 connected with the guide ring 58 and a

pair of guide tube portions 61,61 extending upwardly from the base 60. The interior surface of the base 60 and the portions 61 define a cylindrical surface slightly larger than the exterior dimensions of the container to be measured so that when a container is positioned within the guide tube 56 as shown in Figure 1, the inner surface will guide the container into proper position relative to the datum plate 35 for measurement.

The guide ring extends laterally outwardly from the guide tube 56

and includes a plurality of mounting holes 62 adapted to receive threaded members 65 (Figure 1) for securing the ring 58 and tube 56 to the base assembly 24. The ring also includes an opening 64 to accommodate movement of the

handle assembly rod 66.

As illustrated best in Figures 1 and 15, the handle assembly for moving the datum plate 35 between a raised and lowered position includes a handle 67 and an elongated handle rod 66 extending from one end of the handle 67 to a handle rod link bracket 68. The rod 66 extends through an opening in one

end of the link bracket 66 and is retained relative to the bracket 68 by a pair of spaced collars 69,69 and a compression spring 70. The spring 70 is positioned between the upper collar 69 and a top surface of the bracket 68. The other end of the link bracket 68 is rigidly secured to the lower end of the support post 46 by a pair of set screws. As described in greater detail below, vertical movement of the rod 66 between a raised and lowered position results in corresponding vertical movement of the link bracket 68, the support post 46 and thus the datum plate 35. Movement of the datum plate in a downward direction, however, is limited by engagement between the datum plate 35 and the top of the riser block 31. Further downward movement of the rod 66 through the opening in the forward end of the bracket 68 results in compression of the spring 70. Movement of the rod 66 in an upward direction results in corresponding raising of the link bracket 68, the support post 46 and the datum plate 35.

The handle assembly 59 also includes a handle position lock assembly 140 illustrated best in Figures 1, 15 and 16. The lock assembly 140 includes an inner torque sleeve 141, a piston lock sleeve 142, an outer sleeve 143 and a locking pin 146. The pin 146 extends through the rod 66 and through a slot 147 (Figure 15) in the torque sleeve 141. With this construction, the rod 66 rotates with the sleeve 141, but is able to move axially relative to the sleeve 141. The lower end of the torque sleeve 141 is connected with a torque spring bracket 71. A torsion spring 72 encircles the lower end of the torque sleeve 141, with the legs of the spring engaging the torsion spring posts 73 and 74 connected with the bracket 71 and the guide ring 58, respectively. The action of the torsion spring 72 exerts a rotational force on the bracket 71, and thus the torque sleeve 141 and the rod 66, in a clockwise direction as viewed from the top of the handle 67.

The piston locking sleeve 142 is positioned outside the torque sleeve 141 and is rigidly fixed to the top surface of the guide ring 58. As shown best in Figure 15, the locking sleeve 142 includes an elongated slot 148 and locking recesses 149 and 150 at the top and bottom ends of the slot 148. Rotation of the

handle 67 and thus the rod 66 when the pin is in its raised or lowered position, the pin 146 seats in either the locking recess 149 or the locking recess 150 to retain the datum plate 35 in either a raised or a lowered position, respectively. An outer sleeve 143 encircles the locking sleeve 142 and functions to retain the pin

146, among other things. A pair of retaining rings 143 and 144 are associated with the torque sleeve 141 to secure the sleeve 141 relative to the locking sleeve 142. As shown in Figure 1, the riser block 31 is also preferably provided with a datum plate plunger assembly comprising a plunger 151 which is biased in

an upward direction by a compression spring 152. The plunger 151 and the spring 152 are contained within the opening 153 in the riser block 31. The principal function of this plunger assembly is to resist downward spring forces acting on the datum plate 35, and thus control the downward movement of the datum plate 35 as it approaches the riser block 31 and to exert an upward bias on the datum plate at all times.

In addition to the manual actuation assembly comprising the handle assembly described above, it is contemplated that an automated actuation assembly may also be provided to raise and lower the datum plate. Such automated assembly may include pneumatic or electrical actuators such as air

actuated cylinder or electric solenoids.

Reference is next made to Figures 5, 6 and 7 showing the mechanism 25 for measuring seam height. The mechanism 25 includes a base block 76 rigidly secured to the base plate 32 by the threaded members 78,78 (Figure 16^'

1). A linear slide is connected with the base 76. The linear slide includes a fixed portion 79 connected with the base 76 and a moveable portion 80 having a

forward connecting bracket 81. The portion 80, and the bracket 81, are reciprocally moveable relative to the portion 79. Connected to the bracket 81 by a plurality of threaded members 84 is a housing 82 carrying a linear displacement sensor 85 and a plurality of bearings 86. As illustrated best in Figures 6 and 7, a spring 88 is

provided between a rearward surface of the housing 82 and a forward surface of the base 76 to bias or spring load the housing 82 toward the right as viewed in Figures 6 and 7. Extending through the bearings 86 is a mounting rod 89 having a

collar 90 at its lower end. The upper end of the rod 89 is provided with a seam height measuring member in the form of a chisel tip contact member 91. The member 91 is rigidly connected with the rod 89 at its top end, and is moveable therewith. As shown best in Figure 7, the rod 89, and thus the member 91, is

adapted for vertical up and down movement through the bearings 86. A spring 96 positioned between a portion of the housing 82 and the collar 90 exerts a bias or spring load downwardly on the rod 89 and thus the member 91.

The member 91 includes a contact tip surface or reference edge 92 for

selective engagement with the bottom seam edge of the container seam during a measurement procedure. A support pin 94 extends laterally outwardly from one side surface of the member 91 for engagement with a chisel tip support lever 95 illustrated in Figures 5, 6 and 8.

The support lever 95 is pivotedly mounted to the housing 82 about the pivot point 98 and is movable between a support and a non-support position. The support position is shown in Figures 5 and 6 in which a support shoulder 99 engages and supports the pin 94. This in turn also supports the member 91 and rod 89 in a raised position. In a non-support position, the lever 95 is pivoted forwardly and downwardly so that the pin 94 is disengaged from the shoulder 99.

In this position, the member 91 and rod 89 are allowed to move downwardly as a result of the force of the spring 96.

The lever 95 also includes a roller engagement surface 100 adapted for engagement by the roller 41 (Figure 3) to pivot the lever forwardly or

clockwise as shown in Figure 5 and 6 to a non-support position. A spring member 101 (Figures 5 and 6) positioned within the spring hole 102 (Figure 7) functions to bias the lever 95 in a counterclockwise direction toward a support position.

A pair of ramp members 104 having ramp surfaces 105 and 106 are rigidly joined with the housing 82. As illustrated best in Figure 1, these ramp surfaces are engaged by the roller 41 during upward and downward movement of the datum plate 35. Specifically, as the datum plate moves upwardly to its raised position as illustrated in Figure 1, the roller 41 rolls against the beveled surfaces 105 causing the entire housing 82 and portion 80 to move rearwardly relative to the apparatus base 24 against the force of the spring 88. This outward movement

also causes the member 91 to be moved to a position where it will not interfere with the movement of the container or container seam into a measuring position. Downward movement of the datum plate 35, and thus the roller 41,

causes the roller to roll first along the vertical surface 106 and then along the beveled surface 105, allowing inward movement of the housing 82, and thus the 11 member 91, through force of the spring 88. Such movement is generally parallel to the reference surface. When sufficient inward movement has occurred so that the contact surface 92 is directly over the bottom seam edge, the roller 41 engages

the surface 100, causing forward pivotal movement of the lever 95 and thus release of the pin 94. This allows the rod 89 and member 91 to move downwardly by the force of the spring 96 until the seam contact surface 92 engages the bottom seam edge as shown in Figure 7.

The sensor 85 contained in the housing 82 is retained in a fixed position relative to the housing 82 by a set screw 108. The particular type of sensor is not critical. Preferably, however, the sensor 85 is a linear or linear

displacement sensor or measuring system which measures linear movement or displacement of a reference tip relative to a particular reference or zero point. In the preferred embodiment, the sensor is a spring linear voltage differential transformer (LVDT) sensor with a reference tip 109 for engagement with the

seam contact surface 92. Other sensors known in the art could be used, however, including, among others, proximity sensors, capacitive probe sensors, laser displacement sensors, etc. All of these are referred to herein as linear sensors in that they measure or detect relative movement along a linear path. Preferably

these linear sensors provide data regarding the measurement or linear movement in electronic form. This facilitates automation of the measuring step and electronic storage or other processing of the data such as for statistical process control (SPC) analysis of the seam characteristics of a single container or

comparative analysis of data from a plurality of containers to determine norms, trends and the like. By appropriately positioning, setting and calibrating the sensor 85, it can be used to accurately and repeatably measure the seam height defined by the distance between the seam top and bottom edges by measuring the distance between the reference surface 36 (Figure 3) engaging the top seam edge and the

chisel tip contact surface 92 engaging the bottom seam edge. This distance corresponds to the seam height and is provided from the sensor 85 in electronic form for transmittal to a processing unit such as a computer.

Reference is next made to Figures 9, 10 and 11 illustrating the

mechanism 26 for measuring the seam width. The mechanism 26 includes a base 110 mounted to the base plate 32 (Figure 1) by a plurality of threaded members 111, 111. Connected with the base 110 is a linear slide comprised of a fixed portion 112 rigidly secured to the base 110 and a sliding or moveable portion 114 adapted for sliding reciprocal movement relative to the portion 112. Rigidly connected with the portion 114 and moveable therewith is a sensor mounting bracket 115 having a sensor mounting portion 116 for mounting a linear displacement sensor 118 similar to the sensor 85. The sensor 118 is retained in a fixed position relative to the mounting portion 116 by a set screw positioned within the set screw opening 119. The forward end of the sensor 118 is provided with a moveable seam contact member or reference tip 120 having a seam contact

or lead-in surface 121. Similar to the sensor 85 (Figure 7) described with reference to the seam height measuring mechanism, it is contemplated that a variety of different sensors and in particular linear displacement sensors may be utilized. Positioned at the forward end of the sensor mounting bracket 115 is a ball tip

contact 122 rigidly secured to the mounting bracket 115 via the bracket 124. The II tip contact 122 is adapted for engagement with the inner seam wall when the container seam is in a measuring position. Thus, the seam width measuring mechanism includes first and second opposed seam contact members embodying

the reference tip 120 and the ball tip contact 122, respectively. These members are biased toward one another. The portion 112, and thus the sensor 118, is disposed at an angle relative to the datum plate to provide for the desired measurement position of the seam width.

A bracket rod 125 is rigidly connected with the sensor mounting bracket 115 and extends rearwardly therefrom through a rod opening 129 in the base 110. The rod is provided with a collar 126 at its rearward end and a spring 128 is positioned between a rearward surface of the base 110 and the collar 172.

This spring 128 functions to bias or spring load the mounting bracket 115, and thus the ball tip contact 122 and the sensor 118, toward the right as viewed in Figures 9, 10 and 11. The base 110 also includes a set screw or other threaded member within the set screw opening 130 (Figure 11) to define the rearwardmost or rest position of the bracket 115.

With specific reference to Figure 10, the seam width measuring mechanism 26 can best be understood as follows. As the container (illustrated in

phantom in Figure 10 by the reference number 29) moves downwardly into a measuring position, the inner seam wall engages the surface of the ball tip contact 122 and causes the contact 122, and thus the entire bracket 115, to move forwardly or toward the left as viewed in Figure 10 against the force of the spring

128. At the same time, as the container 29 moves downwardly, the outer seam wall engages the lead-in surface 121 and contact member 120, causing movement of the sensor tip rearwardly relative to the bracket 115. By appropriately positioning the bracket 115 and thus the ball tip contact 122, and by appropriately adjusting and calibrating the sensor 118, the seam width defined by the distance between the inner seam wall which contacts the ball tip contact 122 and the outer

seam wall which contacts the contact member 120 can be accurately and repeatedly measured. Preferably, these measurements are provided in electronic form which are then transmitted to a processing unit for processing, storage and/or analysis.

Reference is next made to Figures 12, 13 and 14 illustrating the mechanism 30 for measuring the countersink depth. Specifically, such mechanism includes a linear displacement sensor 33 having a contact end 131 and a countersink probe assembly 37. As illustrated best in Figure 13, the probe assembly 37 includes a cylindrical support post 132, a probe tip support arm 134 extending outwardly from the post 132, a probe tip 135 and a contact surface 136. When assembled, the support post 132 is slideably received by the cylindrical opening 53 shown best in Figure 14. The support arm 134 extends from the opening 53, through the section 57, to the opening 54 whereby the contact portion 136 is positioned within the opening 54 for contact by the contact tip 131 of the sensor 33. The probe tip 135 extends upwardly through the opening 44 in the datum plate 35 when the datum plate is in a measuring position. It

should be noted that the width of the section 57 and the diameter of the holes 44 are sufficiently large to allow limited rotational movement of the post 132, and

thus the probe tip assembly 35, within the opening 53. This allows the probe tip to seek the deepest part of the countersink portion. Thus, the probe tip is moveable for limited distances in directions perpendicular to and parallel with

the reference surface.

The sensor 33 is retained in the opening 54 by a set screw 138. By appropriate positioning, calibration and adjustment of the sensor 33, the

countersink depth of a container seam can be measured. The measurement data is in electronic form for transmittal processing, storage and /or analysis.

Having described the structure of the preferred embodiment, the operation and method of the present invention can be understood best as

follows. Initially, prior to measurement, the handle assembly 59 and thus the datum plate 35 are locked in a raised or an inoperative position waiting to receive a container to be measured. To measure a container, which in the preferred embodiment is a beverage can 29, the can is manually placed within the guide tube 56 with the seam to be measured facing down. When released, the container seats by gravity so that the top seam edge is in engagement with the reference surface 36 (Figure 3) of the datum plate 35. During this seating, the

beveled surface 38 engages an inner edge portion of the seam to assist in guiding the can 29 and the top seam edge onto the surface 36.

When the datum plate 35 is in its raised or inoperative position, the rollers 41 are engaged with their respective ramp surfaces 106 of the seam height measuring mechanism 25. This keeps the mounting bracket 80 and thus the

member 91 spaced outwardly so as to avoid any interference during downward movement of the can. The seam width measuring mechanism 27 (Figures 9-11) and the countersink depth mechanism 30 (Figures 12-14) are in the positions

illustrated in those figures when the datum plate 35 is raised. When the can is properly seated, the handle assembly 59, and thus the datum plate 35 and the supported can 29, are moved to a lowered measuring

position by rotating the handle 67 counterclockwise to release the pin 146 from the recess 149 (Figure 15). The rod 66 is then moved downwardly until the pin 146 locks in the recess 150. During downward movement of the rod 66, the datum plate also moves downwardly until the datum plate 35 engages the datum

riser block 31. When this occurs, downward movement of the rod 66 will continue for a short distance.

As the handle assembly is lowered to its measuring position, the rollers 41 engage the ramp surfaces 105 (Figures 5 and 6) allowing the bracket 80 and the member 91 to move inwardly toward the surface of the can via force of the spring 88. This movement continues until the inner edge of the member 91 engages the outer surface of the can and the contact surface 92 is above the bottom seam edge. Upon further downward movement of the datum plate 35, the rollers 41 engage their respective roller engagement surfaces 100 (Figures 5,6 and 8). This causes the lever 95 to pivot forwardly and release the pin 94 and member 91. The member 91, and in particular the contact surface 92, is then free

to move downwardly to engage the bottom seam edge. When in this position, the seam height is measured via engagement of the reference tip 109 with the surface 92.

With respect to measurement of the seam width, as the datum plate

35 nears its lowered position, the inner seam surface contacts the ball tip contact 122 (Figures 9-11) and the outer seam surface contacts the lead-in edge 121 and the member 120. Further downward movement of the datum plate causes the A3 ball tip contact to be moved toward the left against the spring 128 and the member 120 to be moved toward the right. Downward movement of the datum plate is continued until it is in its lowered measuring position.

With reference to Figure 12 and the countersink depth measuring

mechanism, as the datum plate 35 nears its lowered, measuring position, the countersink probe tip 135 engages a portion of the sloping countersink portion of the can and moves to its highest level (the deepest level of the can countersink portion). To compensate for tolerances, the probe tip 135 is allowed to float

within the opening 44 in the datum plate 35 to ensure that it locates the deepest portion of the countersink.

After the handle assembly, and thus the datum plate 35, has been locked into its lowered, measuring position, measurements of the seam height, seam width and countersink depth are taken at one or more locations around the periphery of the can seam. In the preferred embodiment, three of each of such measurements are taken at equal distance around the can seam. Thus a total of nine measurements are taken. These measurements are preferably in electronic

form and can be taken continuously and automatically recorded and tabulated, if desired. At the conclusion of measurements, the handle 67 is rotated to release engagement of the pin 146 with the recess 150. This allows the rod 66 and datum plate 35 to move to their raised position. The can can then be removed and a

new one inserted for measurement.

Accordingly, the method aspect of the present invention includes

first loading or positioning a container such as a beverage can relative to a reference surface. In the preferred embodiment, the top seam edge engages a 5,4 reference surface which is horizontally disposed and in which the can is retained in that position by gravity. Secondly, one of a plurality of seam characteristic

measuring mechanisms are provided. Such seam measuring mechanisms can be selected from one or more of a seam height measuring mechanism, a seam width measuring mechanism or a countersink depth measuring mechanism. Thirdly, the can is moved to a measuring position in which the measuring mechanisms are positioned to measure their respective seam characteristics. Preferably, the movement of the can into measuring position automatically results in the measuring mechanisms being properly positioned for the taking of measurements. If a seam height measuring mechanism is utilized, the method includes moving a seam contact member between an inoperative position to allow for movement of the can without interference by such member. Fourthly,

the method includes taking one or more measurements and finally, moving the can to an inoperative position and unloading or removing the can from the apparatus.

Although the description of the preferred embodiment and method has been quite specific, its contemplated various modifications and changes could

be made without deviating from the spirit of the present invention. Accordingly, it is intended that the scope of the present invention be dictated by the appended claims rather than by the description of the preferred embodiment and method.

Claims

1. A device for measuring seam characteristics of a container seam having a seam top edge, a seam bottom edge, a seam inner wall and a seam outer

wall, said device comprising: a reference surface for engagement with said seam top edge; a seam edge contact member having a reference edge for selective engagement with said seam bottom edge; and

a linear sensor associated with one of said reference edge and said reference surface to determine the relative position of said one reference surface and reference edge to thereby determine the seam height defined by the distance between said seam top edge and said seam bottom edge.

2. The device of claim 1 including a container positioning surface on said reference surface.

3. The device of claim 1 wherein said seam edge contact member is movable between a non-operative position in which said reference edge is disengaged relative to said bottom seam edge, and an operative position in which said reference edge is engageable with said bottom seam edge.

4. The device of claim 1 wherein said reference edge is biased toward engagement with said bottom seam edge.

5. The device of claim 1 wherein said seam edge contact is moveable between its non-operative and operative positions along a path generally parallel

to said reference surface.

6. The device of claim 1 wherein said container seam includes a seam width defined by the distance between said seem inner wall and said seam outer

wall and the device includes a seam width measuring mechanism comprising: first and second opposed seam contact members, one of said first and second seam contact members engageable with said seam inner wall and the other of said first and second seam contact members engageable

with said seam outer wall, one of said first and second contact members being connected with a linear sensor.

7. The device of claim 1 wherein said container seam includes a countersink portion positioned at a bottom end of said seam inner wall and a countersink depth defined by the distance between said seam top edge and said countersink portion and wherein the device includes a countersink depth measuring mechanism comprising: a countersink probe engageable with said countersink portion when said top edge is engaged with said reference surface and a linear sensor associated with said counter sink probe.

8. The device of claim 6 wherein said container seam includes a countersink portion positioned at a bottom end of said seam inner wall and a countersink depth defined by the distance between said seam top edge and said

countersink portion and wherein the device includes a countersink depth measuring mechanism comprising: a countersink probe engageable with said countersink portion when said top edge is engaged with said reference surface and a linear sensor

associated with said counter sink probe.

9. The device of claim 1 wherein said device is automated.

10. A device for measuring seam characteristics of a container seam having a seam top edge, a seam bottom edge, a seam inner wall, a seam outer wall, and a seam width defined by the distance between said seam inner wall and

said seam outer wall, said device comprising: a seam width measuring mechanism including first and second opposed seam contact members moveable toward and away from one another, one of said first and second seam contact members engageable

with said seam inner wall and the other of said first and second seam contact members engageable with said seam outer wall, said first and second seam contact member being biased toward one another.

11. The device of claim 10 including a linear sensor having a fixed portion and a moveable tip wherein one of said first and second seam contact members includes said moveable tip.

12. The device of claim 11 including a frame and a slide moveable

relative to said frame and wherein said first and second seam contact members are connected with said slide for movement therewith.

13. The device of claim 11 including a reference surface for engagement with said seam top edge, said reference surface being moveable between an

operative position and a non-operative position and said seam width measuring mechanism being positioned relative to said reference surface so that when said reference surface is moved to its operative position, said container is moved to a position in which said container seam is between said first and second seam

contact members with said first and second seam contact members engaging said seam inner wall and said seam outer wall, respectively.

14. The device of claim 10 where said device is automated.

15. A device for measuring seam characteristics of a container seam having a seam top edge, a seam bottom edge, a seam inner wall, a seam outer wall, a countersink portion defined by the bottom end of said seam inner wall

and a countersink depth defined by the distance between said seam top edge and said countersink portion, said device comprising: a countersink depth measuring mechanism including a reference surface for engagement with said seam top edge; a countersink probe extending outwardly from said reference surface and engageable with said countersink portion; a linear sensor operatively connected with said countersink probe.

16. The device of claim 15 wherein said countersink probe is moveable relative to said reference surface.

17. The device of claim 16 wherein said reference surface is moveable between an operative position and a non-operative position and said countersink is positioned relative to said reference surface so that when said

reference surface is moved to its operative position said container is moved to a

position in which said countersink probe engages said countersink portion.

18. The device of claim 16 wherein said countersink probe is moveable

for limited distances in directions perpendicular to and parallel with said

reference surface.

19. The device of claim 15 wherein said device is automated.

20. A method of measuring seam characteristics of a container seam having a seam top edge, a seam bottom edge, a seam inner wall, a seam outer wall, a countersink portion, a seam height defined by the distance between said

seam top edge and said seam bottom edge, a seam width defined by the distance between said seam inner wall and said seam outer wall and a countersink depth defined by the distance between said seam top edge and said countersink portion, said method comprising: providing a seam measuring device having a reference surface for engagement with said seam top edge and a seam characteristic measuring

mechanism wherein said reference surface and said seam characteristic measuring mechanism are moveable relative to one another between an operative position and an inoperative position; positioning a container on said reference surface with its seam top edge engaging said reference surface; moving said reference surface and said seam characteristic measuring mechanism relative to one another to an operative position and

activating said seam characteristic measuring mechanism to measure a seam characteristic.

21. The method of claim 20 including electronically measuring said

seam characteristic.

22. The method of claim 21 including electronically storing said seam

characteristic in a data base.

23. The method of claim 22 wherein said seam characteristic measuring mechanism is at least one of a seam height measuring mechanism, a seam width measuring mechanism and a countersink depth measuring mechanism.