Rim flattener apparatus and method

An apparatus for forming an upper edge of a paperboard container includes a pocket including a shell having a cavity with a mouth configured to receive the container along an axis such that the rim extends beyond the mouth. A workstation includes a forming member having a first forming surface which is actuatable toward the axis from a retracted position spaced from the rim to an extended position lying adjacent an upper end of the rim, and a forming segment having a second forming surface which is actuatable along the axis and the forming member in response to axial movement thereof such that the second forming surface is positioned spaced from a lower end of the rim. The second forming surface is actuatable along the axis towards the first forming surface to form the rim therebetween.

FIELD OF THE INVENTION

The present invention relates generally to the field of machines that form rims of containers. In particular, the present invention relates to the field of a single machine rim curling and rim flattening device.

BACKGROUND OF THE INVENTION

Rims of containers are often curled to provide the container with a smooth and stronger upper edge. However, curled upper edges provide only a limited amount of surface area (the crown) against which the sealing panel may be secured. As a result, the curls are often flattened to provide a larger surface area against which a sealing panel may be secured. The flattened curl itself is also sealed as a result of the typical thermosplastic coating being melted as the curl is flattened.

Two apparatus are commonly used to curl and flatten the upper edges of paperboard containers. These apparatuses include a two-machine apparatus and a single machine apparatus. A conventional two-machine apparatus generally includes a pocket having an upper perimeter bounded by a concave groove or semi-spherical groove. To curl the rim, a series of tools that have a concave groove or semi-spherical groove are linearly moved towards the pocket so as to deform and curl the upper edge of the paperboard container. The paperboard container is then removed and loaded on to a second flattening machine having a pocket bounded by a flat surface and having a die ring providing an opposing flat surface. The die ring is linearly moved towards the flat surface of the pocket to flatten the curl therebetween. Although conventional, this two-machine apparatus is expensive, space consuming and slow.

A conventional single machine employs a pocket and die ring similar to the pocket and die ring employed by the two-machine process for curling the upper edge of the paperboard container. However, instead of requiring that the paperboard container with a curled rim be removed and reloaded on a separate machine for flattening, the single machine has a series of two heating stations, two curling stations and a flattening station where the machine lifts the container out of the pocket and into the flattener station as four flattening anvils are extended towards one another and about the container under the rim to form a solid ring. A generally flat member is then moved against the anvils to compress and flatten the curled rim therebetween. The order of operation is then reversed to discharge the cup. Although eliminating the need for two separate machines to curl and flatten the paperboard upper edge, such single machine apparatus are still slow since the flattening step requires that the cup be raised and lowered relative to the pocket and also requires that four flattening anvils be extended toward the rim and retracted away from the rim. These additional steps increase process time and costs. The requirement of four stations to rim the container also adds complexity and cost to the machine.

A machine and a method for forming a rim of a paperboard container having a bottom and a sidewall terminating at a rim are disclosed in U.S. Patent Application Publication No. 2002/0111260 published Aug. 15, 2002, the disclosure of which is herein incorporated by reference in entirety. The machine includes a frame, a turret rotatably coupled to the frame, a plurality of circumferentially spaced pockets supported by the turret and a plurality of workstations about the turret. Each pocket includes a shell having a cavity with a mouth configured to receive the container along an axis and a first member about the cavity and including a first surface. The first surface is one of a flat surface and a concave surface and is actuatable along the axis from a retracted position below the mouth to an extended position adjacent the mouth. The plurality of workstations includes a first station and a second station. The first station has a first tool with a second surface, wherein the second surface is one of a flat surface and a concave surface. The first tool is adapted to move along the axis so as to engage and form the paperboard rim between the first and second surfaces. The second station includes a second tool having a third surface, wherein the third surface is the other of a flat surface and a concave surface. The second station further includes a plurality of die segments about the second tool. Each segment has a fourth surface, wherein the fourth surface is the other of a flat surface and a concave surface. The die segments are adapted to move along the axis and to pivot between a closed position in which the fourth surface engages and forms a rim and an opened position.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to an apparatus for forming an upper edge of a paperboard container having a bottom and a sidewall terminating at a rim at the upper edge. The apparatus includes a pocket having a shell provided with a cavity with a mouth configured to receive the container along an axis such that the rim extends beyond the mouth. A workstation includes a forming member separate from the pocket having a first forming surface being one of a flat surface and a concave surface. The first forming surface is actuatable along the axis from a retracted position spaced from the rim to an extended position lying adjacent an upper end of the rim. A forming segment has a second forming surface being one of a flat surface and a concave surface. The forming segment is actuatable towards the axis and the forming member in response to axial movement thereof such that the second forming surface is positioned spaced from a lower end of the rim. The second forming surface is actuatable along the axis towards the first forming surface to form the rim therebetween.

Another embodiment of the invention relates to an apparatus for forming an upper edge of a paperboard container having a bottom and a sidewall terminating at a rim. The apparatus includes a pocket having a shell provided with a cavity with a mouth configured to receive the container such that the rim extends beyond the mouth and the container is centered along an axis of the pocket, the rim being formed with a curl thereon. A flattening station is configured to provide compression and flattening of the curl formed on the rim. The flattening station includes a cam coupled to a forming member having a first forming surface. The cam and the forming member are movable back and forth relative to a support along the axis of the pocket. A set of forming arms is pivotally coupled to the support and is positioned outside the forming member for movement relative thereto. The forming arms are axially movable together with the cam and the forming member. Each of the forming arms has a cam follower engaged with the cam, and a forming segment having a second forming surface facing the first forming surface. The forming member is moved to position the first forming surface on an upper end of the curl on the rim, and the forming arms are pivoted to position each second forming surface spaced from a lower end of the curl on the rim in response to axial movement of the cam and the forming member, and each second forming surface is moved towards the first forming surface to form a flattened rim on the container.

Another embodiment of the invention relates to a method for forming an upper edge of a paperboard container including a bottom and a sidewall terminating in a rim. The method includes the steps of a) positioning the container in a pocket having a mouth such that the rim extends beyond the mouth and such that the container is centered along an axis; b) actuating a forming member having a first forming surface axially along the axis towards and adjacent an upper end of the rim; c) pivoting a forming segment having a second forming surface facing the first forming surface such that the second forming surface lies spaced from a lower end of the rim; and d) actuating at least one of the first forming surface and the second forming surface towards each other to form the rim therebetween.

An additional embodiment of the invention relates to a method of forming an upper edge of a paperboard container including a bottom and a sidewall terminating in a rim. The method includes the steps of a) providing a pocket including a shell having a cavity with a mouth configured to moveably receive the container such that the rim extends beyond the mouth and the container is centered along an axis of the pocket, the rim being formed with a curl thereon; b) providing a cam coupled to a forming member having a first forming surface, the cam and the forming member being axially moveable back and forth relative to a support along the axis of the pocket; c) providing a set of forming arms pivotally coupled to the support and positioned outside the forming member for movement relative thereto, each of the forming arms having a cam follower engaged with the cam, and a forming segment having a second forming surface facing the first forming surface; d) moving the container along the axis in the pocket to advance the rim towards the forming member; e) moving the forming member and each forming segment along the axis towards the pocket until each second forming surface is positioned outside of and beyond a lower end of the rim; f) further moving the forming member along the axis such that the first forming surface lies adjacent an upper end of the rim, such further movement of the forming member enabling each cam follower to move along the respective cam and causing the forming arms to pivot towards the axis and move the forming segments towards the forming member such that the second forming surfaces are positioned spaced from the lower end of the rim and in alignment with the first forming surface; and g) moving the second forming surfaces towards the first forming surface to flatten and compress the curl and form a flattened rim.

DETAILED DESCRIPTION

FIG. 1is a top elevational view of paperboard rim forming apparatus10forming the rim of a paperboard container12(shown inFIG. 3) having a bottom14and a sidewall16terminating at a rim18. Apparatus10generally includes turret22, pockets24, heating station26, curling station28, and flattening station30. Turret22is conventionally known and is rotatably driven about axis32in the direction indicated by arrow34in a conventionally known manner to index and position pockets24sequentially between each of stations26,28and30.

Pockets24are coupled to turret22so as to be rotatably driven about axis32by turret22. In the exemplary embodiment, apparatus10includes seven pockets24circumferentially and equidistantly spaced about turret22. Alternatively, apparatus10may he provided with any of a number of pockets24depending upon the number of stations required to form rim18of container12as well as to possibly form additional portions of container12. Pockets24are each configured to receive and carry an individual container12as apparatus10is forming container12. As a result, rim18of container12may be formed in fewer steps, in less time and with simpler and less expensive equipment.

Heating station26, curling station28and flattening station30are circumferentially positioned about turret22and pockets24and are configured to engage rim18of container12to form rim18. In operation, containers12having unformed rims18are individually loaded into pockets24at loading station38, as indicated by arrow40. Turret22thereafter rotates to position container12across from heating station26. Heating station26directs hot air at rim18to melt the thermoplastic coating on rim18, to render it more pliable for deformation and to allow the flattened rim to seal. Turret22then rotates to position pocket24and its container12across from curling station28. Curling station28forms rim18by curling rim18. Turret22then rotates to position pocket24and its container12across from flattening station30. Flattening station30further forms the curled rim18by compressing and flattening rim18. Thereafter, turret22rotates to position pocket24and formed container12at discharge station42where container12and its completed rim18are ejected, such as by a blower, or otherwise removed from apparatus10as indicated by arrow44.

FIGS. 2-3illustrate turret22, pockets24and the loading of container12into each pocket24in greater detail. As shown byFIG. 2, each pocket24generally includes shell support50, shell52, bottom56, supports70,72,74and cam follower76. Turret22includes cam78and shaft80. Shell support50mounts to turret22(shown inFIG. 2) and is configured for supporting shell52. As will be appreciated, the exact configuration of shell support50may vary depending upon the configuration of turret22and of shell52. Shaft80is fixedly coupled to a machine base20. Cam78is eccentrically mounted upon shaft80and interacts with cam follower76to reciprocate cam follower76in the directions indicated by arrows82and84in a timed relationship with the rotation of turret22, and supporting pockets24.

Shell52is supported by shell support50and includes bottom56defining cavity60. Cavity60forms a mouth62and is configured to receive container12. As shown inFIG. 3, bottom56and sidewall58form an annular groove64configured to receive a lower bottom rim19of container12. Alternatively, groove64may be omitted where container12lacks such a lower bottom rim19. As further shown byFIG. 3, shell support50has a length extending beyond bottom56such that when container12is positioned within cavity60, rim18projects above or generally beyond mouth62. Preferably, pocket24should be configured such that rim18projects above mouth62by a sufficient distance for enabling rim18to be curled and flattened to produce the final container12shown inFIG. 13.

Cam follower76(as shown inFIG. 2) is coupled to support74which is in turn coupled to support72. Support72is coupled to support70which is in turn coupled to bottom56. In the exemplary embodiment, support74is mounted to support72. Support72comprises an elongate cylinder slidably supported by bushing86relative to turret22. Support72is mounted to support70. Support70comprises an elongate cylinder slidably supported by bushing88relative to shell support50. Springs90act against support74to maintain cam follower76against cam78during rotation of turret22. The left-hand section ofFIG. 2illustrates bottom56being moved outward toward mouth62pushing container12out of the pocket24as a result of turret22rotating cam follower76against cam78. As turret22continues to rotate, bottom56is retracted to a starting position.FIG. 2illustrates an actuating mechanism for reciprocating the bottom member56for a purpose to be described hereafter.

FIGS. 4-6illustrate heating station26of apparatus10in greater detail. Heating station26is configured to heat rim18prior to rim18being curled and flattened.FIG. 4illustrates turret22positioning pocket24carrying container12across from and opposite to heating station26. As shown byFIG. 4, heating station26generally includes eccentric shaft100, connecting link102, support104, nozzle support106, heater assembly108and nozzle122. Eccentric shaft100is rotatably supported within heating station26and is rotatably driven in the conventionally known manner by chains or belts.

Eccentric shaft100is pivotably coupled to link102and link102is pivotably coupled to support104through axes110and112. Support104is coupled to nozzle support106which is coupled to nozzle122. Support104is also slidably supported by linear bearing118relative to rim heater base128. Eccentric shaft100, link102, support104and linear bearing118make up a slider-crank mechanism whereby rotational motion of eccentric shaft100causes support104, support106and nozzle122to reciprocate in the directions indicated by arrows114and116in a timed relationship with the rotation of turret22, supporting pockets24.

Heater assembly108is mounted upon rim heater base128and generally includes heater120. Heater120is conventionally known and is configured to heat surrounding air which is supplied by a compressor (not shown). The heated air is blown through the internal passageways124in the direction indicated by arrows126to nozzle122. As shown byFIGS. 5, 6A, and 6B, nozzle122is configured to receive rim18of container12when pocket24is positioned opposite heater station26and when support106and nozzle122have been reciprocated towards pocket24. As best shown byFIGS. 6A and 6B, nozzle122includes internal air passages124which direct the heated air from heater120onto rim18to melt the thermoplastic coating on the paperboard material forming rim18and render it more pliable so that it may be more easily curled at curling station28and may be sealed at flattening station30.

FIGS. 7-9illustrate curling station28in greater detail. As best shown byFIGS. 7 and 8, curling station28generally includes curling station frame186, drive shaft130, cams132,133,134, cam followers136,137,138, inner supports140,142,144,146, forming member148, outer supports150,151,152,154,156, fingers160, forming segments162, springs164and bushings166,167. Shaft130is fixedly coupled to each of cams132,133and134, and is rotatably driven by chains or belts in a conventionally known manner. Cams132,133and134are eccentrically mounted upon shaft130and interact with cam followers136,137and138to reciprocate cam followers136,137and138in the directions indicated by arrows170and172in a timed relationship with the rotation of turret22, supporting pockets24.

Cam follower137is coupled to inner support140which is in turn coupled to support142. Support142is coupled to support144which is in turn coupled to supports146. Support144is coupled to forming member148. In the exemplary embodiment, support140is mounted to support142. Support142comprises an elongate cylinder slidably supported by bushing166relative to outer support152. Support142is mounted to support144. Alternatively, each support140,142,144and146may be fixedly secured to one another by any of a variety of mounting mechanisms. Moreover, one or more of supports140,142,144and146, as well as a forming member148, may alternatively be integrally formed with one another to reduce the number of parts or may be provided by a greater number of individual components secured to one another. Springs (not shown) act against support140to maintain cam follower137against cam133during rotation of shaft130.

Forming member148is mounted to support member144and includes an annular forming surface174(FIGS. 9A-9C) that generally faces pocket24when pocket24is opposite curling station28. In the exemplary embodiment, forming surface174comprises a concave surface to facilitate curling of rim18of container12. In one preferred embodiment, forming member148additionally includes a pancake heater (not shown) between forming member148and support144. The pancake heater heats forming member148to better facilitate curling of rim18by forming surface174. Although forming surface174preferably is annular in shape, forming surface174may alternatively have other continuous shapes depending upon the shape of the container and the rim being formed. For example, forming surface174may have noncircular shapes such as oval or general rectangular shapes.

Cam followers136and138are rotatably coupled to supports150and151which are coupled to support152. Support152is coupled to support154which is coupled to supports156. Supports156are pivotably coupled to each of fingers160which are in turn pivotably coupled to each of forming segments162. Forming segments162are also pivotably coupled to supports146. As shown byFIG. 7, supports150and151comprise elongate cylinders slidably supported by bushings167relative to outer support140. Supports150and151are mounted to support152. Support152is mounted to support154and support154is mounted to supports156. Support152is coupled to bushings (not shown) which are slidably connected to curling station frame186. Springs164act against supports150and151to maintain cam followers136and138against cams132and134during rotation of shaft130.

Fingers160extend between support156and forming segments162and are pivotably coupled to support156about axes176and also pivotably coupled to forming segments162about axes178. As best shown byFIG. 8, fingers160encircle forming member148. In the exemplary embodiment, curling station28includes six such fingers160pivotably coupled to six forming segments162. As will be appreciated, the number of fingers and the number of forming segments may vary depending upon the size and configuration of the container being formed. Referring toFIGS. 9A-9C, each finger160preferably has an adjustable length between pivot points176and178by means of two telescopically mating shafts, wherein the length is generally maintained by a spring180. Compression spring180absorbs any excessive forces acting upon finger160to prevent undue damage to curling station28.

Each forming segment162comprises a generally arcuate segment having a forming surface184. Forming segments162circumscribe generally the entire perimeter of forming member148and are pivotably coupled to fingers160about axes178and are further pivotably coupled to support members146about axes182. Actuation of fingers160towards and away from pocket24by cam followers136and138pivots each of forming segments162in unison between an open position (shown inFIG. 9A) and a closed position (shown inFIG. 9C). In the closed position, each forming surface184generally faces the forming surface174to form rim18therebetween. In the exemplary embodiment, surfaces174and184are both concave so as to curl rim18. In an alternative embodiment, surfaces174and184may be flat so as to alternatively flatten rim18.

FIGS. 9A-9Cillustrate the forming of rim18by surfaces174and184in greater detail.FIG. 9Aillustrates forming member148and fingers160in a retracted position (i.e., pulled back in a direction away from pocket24). As a result, forming segment162is pivoted about axis182to the open position.FIG. 9Billustrates forming member148being moved towards pocket24and into engagement with container12as a result of shaft130rotating cams132,133and134against cam followers136,137and138respectively. As a result, forming surface174forms rim18to partially curl rim18. As shown byFIG. 9C, further rotation of shaft130continues to rotate cams132,133and134against cam followers136,137and138, respectively, so as to move forming member148further towards pocket24and so as to also move fingers160towards pocket24such that forming segments162pivot to the closed position. As a result, forming surfaces174and184engage generally opposite sides of the partially curled rim18to completely curl rim18approximately 360 degrees. Thereafter, continued rotation of shaft130rotates cams132,133and134against cam followers136,137and138, respectively, such that forming member148is withdrawn away from pocket24and such that fingers160are also withdrawn away from pocket24. As a result, forming segments162are once again pivoted to the open position away from pocket24, whereby curling station28is ready to once again form a successive container12appropriately positioned opposite curling station28.

FIGS. 10-12illustrate flattening station30in greater detail. As best shown byFIGS. 10-12, flattening station30generally includes flattening station frame274, shaft230, cams202,203,204,206cam followers208,210,212,214, inner supports240,242,244,246, forming member248, outer supports250,252,254,256,258forming arms260, forming segments262, springs264,276and bushings266,267. Shaft230is fixedly coupled to each of cams202,203and204and is rotatably driven by chains or belts in a conventionally known manner. Cams202,203and204are eccentrically mounted upon shaft230and interact with cam followers208,210and212to reciprocate cam followers208,210and212in the directions indicated by arrows270and272in a timed relationship with the rotation of turret22supporting pockets24.

Cam follower210is coupled to inner support240which is in turn coupled to support242. Support242is coupled to support244which is in turn coupled to support246. Support246is coupled to cam206. Cam206is coupled to forming member248. In the exemplary embodiment, support240is mounted to support242. Support242is mounted to support244. Support244is mounted to support246. Support246comprises an elongate cylinder slidably supported by bushing266relative to outer support258. Support246is mounted to cam206. Cam206is mounted to a forming member248. Alternatively, each support240,242,244and246may he fixedly secured to one another by any of a variety of mounting mechanisms. Moreover, one or more of supports240,242,244and246, as well as cam206and forming member248, may alternatively be integrally formed with one another to reduce the number of parts or may be provided by a greater number of individual components secured to one another. Springs (not shown) act against support242to maintain cam follower210against cam203during rotation of shaft230.

Forming member248is mounted to cam206and includes an annular forming surface280that generally faces pocket24when pocket24is opposite flattening station30. In the exemplary embodiment, forming surface280comprises a flat surface to facilitate flattening of rim18of container12. Although forming surface280preferably is flat in shape, forming surface280may alternatively have other continuous shapes depending upon the shape of the container and the rim being formed. For example, surface280may have round shapes or noncircular shapes such as oval.

Cam followers208and212are rotatably coupled to supports250and252which are coupled to supports254and256which are coupled to support258. Support258is pivotably coupled to each of the forming arms260. Forming segments262are coupled to forming arms260. As shown byFIG. 10, supports250and252comprise elongate cylinders slidably supported by bushings267relative to outer support242. Supports250and252are mounted to supports254and256. Supports254and256are mounted to support258. Springs264act against supports250and252to maintain cam followers208and212against cams202and204during rotation of shaft230. Support258is coupled to bushings (not shown) which are slidably connected to flattening station frame274.

Cam followers214are rotatably coupled to forming arms260. Cam206interacts with cam followers214to pivot forming arms260about axis278. Springs276act against forming arms260to maintain cam followers214against cam206during activation of cam206. As best shown byFIG. 11, forming arms260and forming segments262encircle forming member248. In the exemplary embodiment, flattening station30includes four such forming arms260coupled to four forming segments262. As will be appreciated, the number of forming arms and the number of forming segments may vary depending upon the size and configuration of the container being formed.

Each forming segment262comprises a generally flat segment having a forming surface284. Forming segments262circumscribe generally the entire perimeter of forming member248and are coupled to forming arms260which are pivotably coupled to support258about axes278. Actuation of forming arms260towards and away from pocket24by cam followers208and212and the reciprocation of cam206acting on cam follower214, pivots each of forming segments262in unison between an open position (shown inFIG. 12A) and a closed position (shown inFIG. 12C). In the closed position, each forming surface284generally faces the forming surface280to form rim18therebetween. In the exemplary embodiment, surfaces280and284are both flat so as to flatten rim18. In an alternative embodiment, surfaces280and284may be curved.

FIGS. 12A-12Dillustrate the forming of rim18by forming surfaces280and284in greater detail.FIG. 12Aillustrates forming arms260and forming member248in a retracted position (i.e., pulled back in a direction away from pocket24). As a result, forming arms260are pivoted about axes278to the open position. The left-hand section ofFIG. 2illustrates shell bottom56being moved outward toward mouth62pushing container12out of the pocket24as a result of turret22rotating cam follower76against cam78. As a result, container12is now in a position where the flattener station30can now flatten curled rim18.FIG. 12Billustrates forming members248and262being moved towards pocket24as a result of shaft230rotating cams202,203and204against cam followers208,210and212, respectively. Forming members262now stop their forward travel. As shown byFIG. 12C, further rotation of shaft230continues to rotate cams202,203and204against cam followers208,210and212, respectively, so as to move forming member248further towards pocket24until forming surface280touches curled rim18. As a result, cam followers214, on forming arms260, follow the cam surface on cam206causing the forming arms260and forming members262to pivot about axes278closing forming members262around rim18. Thereafter, continued rotation of shaft230rotates cams202,203and204against cam followers208,210and212, respectively, such that forming member262moves outwardly from pocket24so that forming surface284engages the curled rim18. As a result, rim18is captured between surfaces280and284and is compressed or flattened as depicted inFIG. 12D. Afterwards, continued rotation of shaft230retracts forming members248and262away from pocket24and turret22rotates pocket24to the next station, thereby positioning the next successive pocket carrying the curled, but unflattened rim18across from flattening station30.

FIG. 13is a fragmentary sectional view of container12after the rim18has been curled and flattened by apparatus10. As best seen inFIG. 13, flattening station30compresses and flattens rim18such that the rim18is generally flat along both its upper and lower surfaces. Because rim18is not only flattened on both sides but is also compressed, any step along the seam of the paperboard material is minimized. As a result, the seal between the sealing panel typically positioned across the opening of container12and sealed to the flat upper surface of rim18is more reliable and less susceptible to damage.

Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention as set forth in the appended claims.