Packaging machine with rotary top sealer

Information

  • Patent Grant
  • 6212859
  • Patent Number
    6,212,859
  • Date Filed
    Tuesday, May 19, 1998
    26 years ago
  • Date Issued
    Tuesday, April 10, 2001
    23 years ago
Abstract
A method of continuously forming, filling and sealing of packages with a continuous web of film material is disclosed and comprises the steps of providing a continuous web of film material and folding the web to provide confronting sides joined along a bottom edge and forming a vertical seal at spaced intervals along the web. This process forms a series of horizontally disposed pouches having opposed sidewalls separated by the vertical seals with each pouch being unsealed along a top edge. The pouches are then opened by separating the opposed sidewalls and are then filled with a product. After the pouches are filled, the top edge of each pouch is sealed together to enclose the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches. This sealing method enables the packages to receive a greater amount of fill while still being able to provide a smooth, uniform seal.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates generally to an improved packaging machine concerning the method and apparatus for continuously forming, filling and sealing packages while linked together to a continuous web of material. More specifically the present invention provides an improved horizontal top sealer that allows packages to hold a greater volume of fill while providing a smooth, uniform seal across the top horizontal edge.




2. Description of the Prior Art




Various prior art packaging machine devices are known in the art. In general, packaging machines are categorized into horizontal and vertical machines depending on the general direction of movement of a continuous web of material. The present invention relates to a horizontal packaging machine with an improved horizontal rotary top sealer and is designed to operate in a continuous manner.




In the manufacturing and production of packaged goods, cost factors are highly related to the costs of materials used in the packaging process. In the group of materials commonly found in continuous webs of film material: PET and polyethylene, and paper-polyethylene have heat sealable synthetic films that have a relatively low cost in comparison to other film materials. With these principles in mind, the present machine was developed to produce fusible film packages on a large production basis to be used for packaging products such as food powders, small candies, and the like. The machine and method further enables packages to be formed having a further expanded capacity for receiving an even greater volume of fill than prior packaging methods.




A number of U.S. patents have issued to a couple of the above-identified inventors concerning various packaging machine methods and apparatuses, with the following list being only a brief representative list of some issued patents to serve as additional background information in the field of continuously operating horizontal packaging machines:




















U.S. Pat. No.




Inventor




Date of Issue













3,453,799




Cloud et al.




July 8, 1969







3,478,492




Cloud et al.




November 18, 1969







3,505,776




Cloud




April 14, 1970







3,597,898




Cloud




August 10, 1971







3,667,188




Benner and Cloud




June 6, 1972







5,094,657




Dworak and Cloud




March 10, 1992







5,722,217




Cloud




March 3, 1998















These and other types of packaging machines used in the past do not offer the flexibility and inventive features of our packaging machine with a rotary top sealer. As will be described in greater detail hereinafter, the method and apparatus of the present invention differs from those previously proposed and employs a number of novel features that render it highly advantageous over the prior art.




SUMMARY OF THE INVENTION




The present invention relates to a horizontal packaging machine with a rotary top sealer and is designed to operate in a continuous manner utilizing a continuous web of film material for automatically forming, filling and sealing packages.




Accordingly, it is an object of this invention to provide an improved method and apparatus for manufacture of filled packages from a continuous web of material, which packages are formed, filled and sealed using a rotary top sealer while linked together to the web.




Another object of this invention is to provide an improved method and apparatus for manufacture of filled packages made from oriented polymers such as polypropylene, nylon, and polyester with seals that do not exhibit distortion wrinkles, and more particularly providing a rotary top sealer that allows the filled packages to hold a greater volume of fill while still providing a uniform, smooth seal across the top edge of the filled packages.




To achieve the foregoing and other objectives, and in accordance with the purposes of the present invention, a method and apparatus of continuously forming, filling and sealing of packages with a continuous web of film material is provided. The method includes the steps of providing a continuous web of film material and folding the web to provide confronting sides joined along a bottom edge, then forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge. The pouches are then opened by separating the opposed sidewalls and then the pouches are filled with a material. The top edge of each pouch is then sealed to close the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches.




In accordance with an aspect of the invention, the horizontal rotary seal former has a heated circular sealer plate mounted for rotation. The heated circular sealer plate has a flat outer surface positioned about its circumference for engagement with an upper portion of the pouches for progressively forming a continuous horizontal seal as the web is continuously moved along with the circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed.




Still another feature of this invention concerns the horizontal rotary seal former as described above, wherein the horizontal rotary seal former further includes a land plate and a plurality of lands, the land plate has a diameter slightly smaller than the heated circular sealer plate and is positioned directly below the heated circular sealer plate. The land plate is mounted in corresponding rotation with the heated circular sealer plate, each of the lands has a relatively rectangular shape and has a thickness less than a thickness of the vertical seals on the series of horizontally disposed pouches. The plurality of lands are pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate. The plurality of lands are equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed filled pouches, whereby when the web of horizontally disposed pouches are trained onto the horizontal seal former to join and seal the upper portion of the pouches, the vertical seals extending below the upper edge of the filled pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed pouches properly aligned.




Yet another feature of the present invention concerns the packaging apparatus as described above, wherein the horizontal rotary seal former further includes a land stop, the land stop acts to stop each of the lands from pivoting radially inward beyond a predetermined distance.




A still further feature of the invention concerns the packaging apparatus as described above, wherein the horizontal rotary seal former further includes a bottom plate. The bottom plate has a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate. The bottom plate is positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed pouches to rest thereon.




An even further feature of the invention concerns the packaging apparatus as described above, wherein the position of the bottom plate in the horizontal rotary seal former is adjustable at varying heights to accommodate pouches of varying lengths.




Yet still another feature of the invention concerns the packaging apparatus as described above, further comprising at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the flat outer surface of the heated circular sealer plate in order to help seal and align the upper portion of the web of horizontally disposed pouches.











Other objects, features and advantages of the invention will become more readily apparent upon reference to the following description when taken in conjunction with the accompanying drawings, which drawings illustrate several embodiments of the invention.




DESCRIPTION OF THE DRAWINGS





FIG. 1

is a diagrammatic perspective view of the present invention;





FIG. 2

is a top plan view of the present invention;





FIG. 3

is a side plan view of the present invention embodying important features of the present invention taken along line


3





3


of

FIG. 2

;





FIG. 4

is a fragmentary perspective view of the rotary top sealer of the present invention;





FIG. 5

is a fragmentary cross-sectional side plan view of the gearing mechanism used with the rotary top sealer taken along line


5





5


of

FIG. 4

;





FIG. 6

is a fragmentary top plan view of the rotary top sealer gearing mechanism taken along line


6





6


of

FIG. 5

;





FIG. 7

is a fragmentary top plan view of the sealer plate and heating element of the rotary top sealer taken along line


7





7


of

FIG. 5

;





FIG. 8

is a fragmentary top plan view of the rotary top sealer as taken along line


8





8


of

FIG. 5

embodying further important features of the present invention;





FIG. 9

is a fragmentary top plan view of the rotary top sealer as taken along line


9





9


of

FIG. 5

;





FIG. 10

is an enlarged partial cross-sectional side view illustrating the connection of the wear plate to the hydraulic cylinders taken along line


10





10


of

FIG. 9

;





FIG. 11

is an enlarged partial perspective view of the rotary top sealer illustrating how the lands are connected to the land plate;





FIG. 12

is an enlarged partial cross-sectional side view taken along line


12





12


of

FIG. 8

illustrating the land stops of the rotary top sealer;





FIG. 13

is an enlarged partial cross-sectional side view illustrating how the land stops of the rotary top sealer can be adjusted;





FIG. 14

is an enlarged partial cross-sectional side view illustrating how the height of the bottom plate can be adjusted to accommodate packages of different heights;





FIG. 15

is an enlarged partial cross-sectional side view illustrating how packages are sealed and rotated about the rotary top sealer of the present invention;





FIG. 16

is a perspective view of a sealed package using the rotary top sealer of the present invention; and





FIG. 17

is a perspective view of a sealed package utilizing the prior art of sealing top edges of packages.











DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring now to the drawings, a packaging machine


10


is illustrated in FIG.


1


. The present machine


10


is a horizontal type packaging machine and is capable of producing filled packages


12


at a high rate of production. The packages


12


are produced from a continuous strip or web of film material


14


or from several continuous webs of laminated film materials, as desired. The web is formed of film materials such as: PET and polyethylene; paper-polyethylene; or any other types of sealable film material, which provides for an inexpensive packaging material. Additionally, the web may be pre-printed.




A coiled roll of the continuous web


14


of film material is initially provided. A suitable strip plow


16


acts to fold the web


14


to provide confronting sides


18


joined along a bottom edge


20


of the web


14


. A guide roller


22


then directs the web onto a rotating vertical seal former


24


to form a plurality of vertical seals


25


extending from the bottom edge of the web to the top edge of the web. The vertical seal former has a plurality of elongated circumferentially spaced vertical sealers


26


located at an outside surface of the vertical seal former


24


, as best illustrated in FIG.


1


.




In order to form vertical seals


25


, the web


14


is pressed against the elongated circumferentially spaced vertical sealers


26


to progressively form vertical seals


25


as the web is being continuously moved with the rotating vertical seal former


24


while at the same time applying an adequate temperature to provide a sealing action and allowing the area of the film being sealed to be progressively formed or cooked. As the vertical seals are formed, the confronting sides


18


of the web


14


are melted together along the area of the vertical sealers


26


, with the vertical sealers then melting through the web


14


to form a vertical seal


25


along each adjacent side of the vertical sealers


26


. Once the vertical seals


25


have been completed, a series of horizontally disposed pouches


28


have been produced. It is to be understood that other types of pouch creating methods can be employed with the features of the present invention.




The newly formed horizontally disposed pouches


28


are now directed towards the filling station


30


. The filling station comprises of a vacuum transfer wheel


32


positioned directly beneath a filler transfer wheel


34


. As the pouches


28


enter the filling station


30


, the pouches are opened by the vacuum transfer wheel


32


(

FIG. 2

) by separating the opposing sidewalls of each pouch. It is to be understood that the pouches


28


can be opened by a variety of different methods, including forcing air into the top edge of each pouch, as well as providing a vacuum suction on a central portion of the opposing sidewalls on each pouch to separate the sidewalls from each other.




As the newly opened pouches


28


are rotated about the filling station


30


, each of the pouches are then progressively filled from the filler transfer wheel


34


through filling spouts


36


positioned directly above a central portion of the opened pouches. In the present invention, the pouches


28


can be filled to a greater extent and allowing the pouches to take on a bulged shape or appearance, as shown in FIG.


15


. It is to be understood that other types of filling methods can be employed with the features of the present invention.




After each pouch


28


has been filled, the web


14


is then immediately directed around a horizontal rotary top sealer


37


. The rotary top sealer


37


can be positioned adjacent to the filling station


30


and can be directly tied mechanically to the filling station gearing mechanism in order to have consistently aligned rotating units. As can be seen in

FIGS. 5 and 6

, the filler transfer wheel is timed to work with the rotary top sealer shaft


40


through a series of chains


42


,


44


,


46


, and gears and sprockets


48


,


50


,


52


,


54


,


56


,


58


,


60


. As is illustrated in

FIG. 6

, the chains, gears and sprockets provide a reverse rotation of the rotary top sealer relative to the filling station. The filling station chain


42


is connected from the filling station


30


, and through a series of chains and gears, powers the rotary top sealer shaft


40


. This gearing mechanisms enables the filled packages to smoothly transfer from the filling station


30


to the rotary top sealer


37


. Various different motors and other different methods and designs can be employed to power the devices of the present invention and are not the subject of the invention herein disclosed.




Excellent results can be obtained when the rotary top sealer


37


is located as close to the filling station


30


as possible in order to minimize the length of unsupported web between the two units. The lands


64


(

FIG. 4

) of the rotary top sealer


37


are in phase with the lands


65


(

FIG. 2

) on the vacuum transfer wheel. This provides a smooth transition of the web to the rotary top sealer


37


. Since the lands


64


of the rotary top sealer only contact the vertical seal of the pouch product, disturbance within the pouch


28


is minimized.




Each of the lands


64


has a relatively rectangular shape and has a thickness less than a thickness of the vertical seals on the series of horizontally disposed pouches


28


. A land plate


66


is positioned directly below the heated circular sealer plate


80


. The land plate


66


has a diameter smaller than the heated circular sealer plate and is mounted in corresponding rotation with the sealer plate


80


. Each of the lands


64


are pivotally mounted with a mounting bracket


67


and a pivot pin


68


at an upper end along the outer edge of the land plate


66


allowing each of the lands to freely pivot radially inward and extend vertically downward. The plurality of lands are equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches


28


, whereby when the horizontally disposed adjoining pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands


64


and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned.




As can be seen in

FIGS. 5

,


12


,


13


,


14


, and


15


, the rotary top sealer lands


64


are allowed to pivot inward until they rest against a land stop


69


. Land stop settings are adjustable in order to accommodate different pouch fills. The land stops


69


are mounted in a bottom plate


70


and are allowed to slide through a bearing


72


in an inward radial direction.




The land stops


69


are spring loaded with coiled springs


71


inwardly against a non-rotating fixed cone


74


. The vertical height of the cone


74


can be changed (

FIGS. 5

,


14


) while the rotary top sealer


37


is running through the use of two screw assemblies


75


,


76


. This then allows uniform adjustment of the inward pivot movement of the lands.




Six posts


78


which are mounted to the sealer plate


80


provide the mounting for a bottom plate


70


. The bottom plate


70


has a diameter similar to the sealer plate


80


and contains clearance slots


82


for the lands and holes with bushings


84


for the posts


78


to slip through. This allows the bottom plate to have a corresponding equivalent rotation with the sealer plate


80


. Springs


86


are fitted over the posts


78


and hold the bottom plate


70


against the wear plate


88


. The wear plate


88


is mounted to four hydraulic cylinders


90


which provide dynamic adjustment. This adjustment allows the bottom plate to move up and down and is necessary for package height and package fill changes. For clarity purposes,

FIGS. 5 and 14

do not show all of the posts and lands extending around the rotary top sealer


37


.




The sealer plate


80


contains a heating element


81


to heat the sealer plate, particularly the outer edge, and is designed to be slightly larger than the land plate


66


to help iron out wrinkles in the packages


28


that are being sealed, thereby providing a smooth top seal. Since the smooth top seal is created by training the upper edge of the pouches along a circular sealer wherein the top edge is progressively stretched and closed, the packages can then accommodate a greater amount of product fill than prior top sealing devices. This sealing method provides for a filled package


100


(

FIG. 16

) that has a smooth hermetic top seal


102


. Using the same amount of package filling, the prior art sealing methods does not consistently provide a uniform hermetic seal as is shown in the package


104


and seal


106


in FIG.


17


. The lands


64


and the bottom plate


70


help keep large pouches with a heavier product fill properly aligned and supported as the top seal is created. Smaller packages with a light fill may not require the use of lands or the bottom plate. As long as there is a sufficient tension in the web of pouches traveling around the top sealer, lighter and smaller packages may not require the support provided by the lands and the bottom plate. However, the use of a circular sealer enables the packages to contain a greater amount of fill then prior sealing devices allow.




As the web of pouches is trained onto the horizontal rotary top sealer


37


, the heated sealer plate


80


progressively forms a continuous horizontal seal as the top edge of each pouch is continuously moved radially and circumferentially about the outer edge of the heated circular sealer plate


80


. The heated circular sealer plate


80


provides an adequate temperature to provide a sealing action to the top edge of each pouch contacting the sealer plate and smoothly seals and encloses the filled pouches.




Depending on the size of the packages used and the amount of fill placed within the packages, backup rollers or press rollers


108


may need to be used to provide pressure against the upper edge of the web of pouches


28


and the sealer plate


80


. The backup rollers are mounted for counter-rotation pressing engagement against the rotating circumference of the heated circular sealer plate


80


in order to pinch and seal the top edge of the pouches. Excellent results are obtained when using a backup roller with larger packages containing a heavier fill. Smaller packages with a light powder fill may not require the use of backup rollers to create a uniform top seal, and wherein the web of packages has a sufficient tension to create a proper seal.




In the design of the presently disclosed invention, the web of pouches


28


exits the rotary top sealer unit


37


180 degrees from the entering point. It is not essential for the web of pouches to travel a full 180 degrees around the rotary top sealer, but it is necessary for the upper edge of film material to be in contact with the sealer plate for a predetermined amount of time over a portion of the sealer plate in order to provide an adequate seal. Excellent results can be obtained when a film/film structure such as PET-polyethylene material is in contact with the sealer plate having a temperature between 400-410 degrees for approximately one (1) second. Other types of fusible film materials may require more or less time to adequately seal the packages and appropriate adjustments regarding the temperature of the sealer plate and the speed of rotation can be made.




After the top seal has been created, the web of sealed packages then continues onto a cutter that separates the packages from the continuous web, wherein the packages are then ultimately boxed for distribution.




Although the invention has been described by reference to some embodiments, it is not intended that the novel device be limited thereby, but that modifications thereof are intended to be included as falling within the broad scope and spirit of the foregoing disclosure, the following claims and the appended drawings.



Claims
  • 1. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material; and f) sealing the top edge of each pouch together to close the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches, said horizontal rotary sealer having means to provide a vertical support to said continuous web of film material such that said means to provide a vertical support to said continuous web of film material contacts only said vertical seal of said pouch without contacting confronting sides of said filled pouch so that disturbance of the material within said pouch is minimized as the top edge is sealed.
  • 2. The method of claim 1, further comprising the step of supporting a bottom portion of each pouch while sealing the top edge, wherein the horizontal rotary sealer further includes a bottom plate, the bottom plate being mounted in corresponding rotation with the heated circular sealer plate and is positioned a predetermined distance below the heated circular sealer plate to allow the bottom portion of the horizontally disposed adjoining pouches to rest thereon.
  • 3. The method of claim 2, wherein the position of the bottom plate is adjustable at varying heights to accommodate pouches of different heights.
  • 4. The method of claim 1, further comprising the step of keeping the web of horizontally disposed adjoining pouches properly aligned while sealing the top edge, wherein the horizontal rotary sealer further includes a land plate and a plurality of lands, the land plate having a diameter slightly smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches, whereby when the horizontally disposed adjoining pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned.
  • 5. The method of claim 4, wherein the horizontal rotary sealer further includes a land stop means, the land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 6. The method of claim 1, further comprising the step of training the web of horizontally disposed adjoining pouches about a portion of the circumference of the horizontal rotary sealer while sealing the top edge.
  • 7. The method of claim 1, wherein the horizontal rotary sealer further includes at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the heated circular sealer plate in order to help seal and align the top edge of the web of horizontally disposed pouches.
  • 8. A method of forming a horizontal top seal for use in a packaging machine having a continuous web of film material having a series of horizontally disposed filled pouches separated by vertical seals extending transversely of the web and having opposed sidewalls of each pouch unsealed along a top edge, the method comprising training the horizontally disposed filled pouches onto a horizontal rotary sealer, having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be gently joined together and smoothly sealed to enclose the filled pouches,said horizontal rotary sealer having means to provide a vertical support to said continuous web of film material such that said means to provide a vertical support to said continuous web of film material contacts only said vertical seal of said pouch without contacting said opposed sidewalls of said filled pouch so that disturbance of the material within said pouch is minimized as the top edge is sealed.
  • 9. The method of claim 8, further comprising the step of supporting a bottom portion of each pouch while sealing the top edge, wherein the horizontal rotary sealer further includes a bottom plate, the bottom plate being mounted in corresponding rotation with the heated circular sealer plate and is positioned a predetermined distance below the heated circular sealer plate to allow the bottom portion of the horizontally disposed filled pouches to rest thereon.
  • 10. The method of claim 9, wherein the position of the bottom plate is adjustable at varying heights to accommodate pouches of different heights.
  • 11. The method of claim 8, further comprising the step of keeping the web of horizontally disposed filled pouches properly aligned while sealing the top edge, wherein the horizontal rotary sealer further includes a land plate and a plurality of lands, the land plate having a diameter slightly smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed filled pouches, whereby when the horizontally disposed filled pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the filled pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed filled pouches properly aligned.
  • 12. The method of claim 11, wherein the horizontal rotary sealer further includes a land stop means, the land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 13. The method of claim 8, further comprising the step of training the web of horizontally filled pouches about a portion of the circumference of the horizontal rotary sealer while sealing the top edge.
  • 14. The method of claim 8, wherein the horizontal rotary sealer further includes at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the heated circular sealer plate in order to help seal and align the top edge of the web of horizontally disposed filled pouches.
  • 15. A packaging apparatus, comprising:a) means for feeding a continuous web of film material having confronting sides; b) means for forming vertical seals in the web to form a series of horizontally disposed pouches separated by the vertical seals, the vertical seals extending transversely of the web from a bottom edge of the pouch to an upper portion of the pouch; c) means for opening the pouches by separating opposed sidewalls of the pouches; d) means for filling the pouches with a material to form outwardly bulged sidewalls; and e) a horizontal rotary seal former having a heated circular sealer plate mounted for rotation, the heated circular sealer plate having a flat outer surface positioned about its circumference for engagement with an upper portion of the pouches for progressively forming a continuous horizontal seal as the web is being continuously moved along with the circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed, said horizontal rotary sealer having means to provide a vertical support to said continuous web of film material such that said means to provide a vertical support to said continuous web of film material contacts only said vertical seal of said pouch without contacting said confronting sides of said filled pouch so that disturbance of the material within said vouch is minimized as the top edge is sealed.
  • 16. The packaging apparatus of claim 15, wherein the horizontal rotary seal former further includes a land plate and a plurality of lands, said land plate being positioned directly below the heated circular sealer plate, said land plate being mounted in corresponding rotation with the heated circular sealer plate, each of said lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed pouches, said plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of said lands to freely pivot radially inward and extend vertically downward from the land plate, said plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed filled pouches, whereby when the web of horizontally disposed pouches are trained onto the horizontal seal former to join and seal the upper portion of the pouches, the vertical seals extending below the upper edge of the filled pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed pouches properly aligned.
  • 17. The packaging apparatus of claim 16, wherein the horizontal rotary seal former further includes a land stop means, said land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 18. The packaging apparatus of claim 16, wherein the horizontal rotary seal former further includes a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed pouches to rest thereon.
  • 19. The packaging apparatus of claim 18, wherein the position of the bottom plate in the horizontal rotary seal former is adjustable at varying heights to accommodate pouches of varying lengths.
  • 20. The packaging apparatus of claim 15, wherein the horizontal rotary seal former further includes a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed pouches to rest thereon.
  • 21. The packaging apparatus of claim 15, further comprising at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the flat outer surface of the heated circular sealer plate in order to help seal and align the upper portion of the web of horizontally disposed pouches.
  • 22. A horizontal seal former device for use with a continuous web of film material having confronting sides and a series of horizontally disposed filled pouches defined by a series of vertical seals extending transversely of the web from a bottom edge of the pouch to an upper portion of the pouch, the device comprising: a top seal shaft, said top seal shaft being connected to a rotating means for rotating said top seal shaft, a heated circular sealer plate mounted for rotation on said top seal shaft, said circular sealer plate having a flat outer surface positioned about its circumference for engagement with an upper portion of a continuous web of filled pouches for progressively forming a continuous horizontal seal as the web is moved along with the rotating circumference of the flat outer surface while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed to enclose the filled pouches,said circular sealer plate further having means to provide a vertical support to said continuous web of film material such that said means to provide a vertical support to said continuous web of film material contacts only said vertical seal of said pouch without contacting said confronting sides of said filled pouch so that disturbance of the material within said pouch is minimized as the top edge is sealed.
  • 23. The horizontal seal former device of claim 22, further including a land plate and a plurality of lands, said land plate being positioned directly below the heated circular sealer plate and is mounted in corresponding rotation with the circular sealer plate, each of said lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed filled pouches, said plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of said lands to freely pivot radially inward and extend vertically downward from the land plate, said plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed filled pouches, whereby when the horizontally disposed filled pouches are trained onto the horizontal seal former to join and seal the upper portion of the filled pouches, the vertical seals extending below the upper edge of the filled pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed filled pouches properly aligned.
  • 24. The horizontal seal former device of claim 23, further including a land stop means, said land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 25. The horizontal seal former device of claim 23, further including a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed filled pouches to rest thereon.
  • 26. The horizontal seal former device of claim 25, wherein the position of the bottom plate is adjustable at varying heights to accommodate pouches of varying lengths.
  • 27. The horizontal seal former device of claim 22, further including a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed filled pouches to rest thereon.
  • 28. The horizontal seal former device of claim 22, further comprising at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the flat outer surface of the heated circular sealer plate in order to help seal and align the upper portion of the web of horizontally disposed filled pouches.
  • 29. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material to form outwardly bulged sidewalls; and f) radially and circumferentially moving the open filled pouches in union with a circumferentially moving heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edges of each pouch to be joined together and smoothly sealed to enclose the filled pouches, said moving heated circular sealer plate having means to provide a vertical support to said continuous web of film material such that said means to provide a vertical support to said continuous web of film material contacts only said vertical seal of said pouch without contacting said outwardly bulged sidewalls of said filled pouch so that disturbance of the material within said pouch is minimized as the top edge is sealed.
  • 30. The method of claim 29, further comprising the step of supporting a bottom portion of each pouch while moving the open filled pouches in union with the circumferentially moving heated circular sealer plate, wherein the heated circular sealer plate further includes a bottom plate, the bottom plate being mounted in corresponding rotation with the heated circular sealer plate and is positioned a predetermined distance below the heated circular sealer plate to allow the bottom portion of the horizontally disposed adjoining pouches to rest thereon.
  • 31. The method of claim 30, wherein the position of the bottom plate is adjustable at varying heights to accommodate pouches of different heights.
  • 32. The method of claim 29, further comprising the step of keeping the web of horizontally disposed adjoining pouches properly aligned while moving the open filled pouches in union with the circumferentially moving heated circular sealer plate, wherein the heated circular sealer plate further includes a land plate and a plurality of lands, the land plate having a diameter smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches, whereby when the horizontally disposed adjoining pouches are trained onto the heated circular sealer plate to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned.
  • 33. The method of claim 32, wherein the heated circular sealer plate further includes a land stop means, the land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 34. The method of claim 29, further comprising the step of training the web of horizontally disposed adjoining pouches about a portion of the circumference of the heated circular sealer plate while sealing the top edge.
  • 35. The method of claim 29, wherein the heated circular sealer plate further includes at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the heated circular sealer plate in order to help seal and align the top edge of the web of horizontally disposed pouches.
  • 36. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material; and f) sealing the top edge of each pouch together to close the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches, and maintaining the web of horizontally disposed adjoining pouches properly aligned while sealing the top edge, wherein the horizontal rotary sealer further includes a land plate and a plurality of lands, the land plate having a diameter slightly smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches, whereby when the horizontally disposed adjoining pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned.
  • 37. The method of claim 36, wherein the horizontal rotary sealer further includes a land stop means, the land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 38. A packaging apparatus, comprising:a) means for feeding a continuous web of film material having confronting sides; b) means for forming vertical seals in the web to form a series of horizontally disposed pouches separated by the vertical seals, the vertical seals extending transversely of the web from a bottom edge of the pouch to an upper portion of the pouch; c) means for opening the pouches by separating opposed sidewalls of the pouches; d) means for filling the pouches with a material; and e) a horizontal rotary seal former having a heated circular sealer plate mounted for rotation, the heated circular sealer plate having a flat outer surface positioned about its circumference for engagement with an upper portion of the pouches for progressively forming a continuous horizontal seal as the web is being continuously moved along with the circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed, the horizontal rotary seal former having a land plate and a plurality of lands, said land plate being positioned directly below the heated circular sealer plate, said land plate being mounted in corresponding rotation with the heated circular sealer plate, each of said lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed pouches, said plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of said lands to freely pivot radially inward and extend vertically downward from the land plate, said plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed filled pouches, whereby when the web of horizontally disposed pouches are trained onto the horizontal seal former to join and seal the upper portion of the pouches, the vertical seals extending below the upper edge of the filled pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed pouches properly aligned.
  • 39. The packaging apparatus of claim 38, wherein the horizontal rotary seal former further includes a land stop means, said land stop means acting to stop each of the lands from pivoting radially inward beyond a predetermined distance.
  • 40. The packaging apparatus of claim 38, wherein the horizontal rotary seal former further includes a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed pouches to rest thereon.
  • 41. The packaging apparatus of claim 40, wherein the position of the bottom plate in the horizontal rotary seal former is adjustable at varying heights to accommodate pouches of varying lengths.
  • 42. The packaging apparatus of claim 38 wherein the horizontal rotary seal former further includes a bottom plate, said bottom plate having a diameter equivalent to the heated circular sealer plate and is mounted in corresponding rotation with the heated circular sealer plate, said bottom plate being positioned a predetermined distance below the heated circular sealer plate to allow the bottom edge of the horizontally disposed pouches to rest thereon.
  • 43. The packaging apparatus of claim 38, further comprising at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the flat outer surface of the heated circular sealer plate in order to help seal and align the upper portion of the web of horizontally disposed pouches.
  • 44. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material; f) sealing the top edge of each pouch together to close the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches, and maintaining the web of horizontally disposed adjoining pouches properly aligned while sealing the top edge, wherein the horizontal rotary sealer further includes a land plate and a plurality of lands, the land plate having a diameter slightly smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches, whereby when the horizontally disposed adjoining pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned; and g) supporting a bottom portion of each pouch while sealing the top edge, wherein the horizontal rotary sealer further includes a bottom plate, the bottom plate being mounted in corresponding rotation with the heated circular sealer plate and is positioned a predetermined distance below the heated circular sealer plate to allow the bottom portion of the horizontally disposed adjoining pouches to rest thereon.
  • 45. The method of claim 44, wherein the position of the bottom plate is adjustable at varying heights to accommodate pouches of different heights.
  • 46. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material; f) sealing the top edge of each pouch together to close the filled pouches by training the pouches onto a horizontal rotary sealer having a heated circular sealer plate and progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches, and maintaining the web of horizontally disposed adjoining pouches properly aligned while sealing the top edge, wherein the horizontal rotary sealer further includes a land plate and a plurality of lands, the land plate having a diameter slightly smaller than the heated circular sealer plate and being positioned directly below the heated circular sealer plate, the land plate being mounted in corresponding rotation with the circular sealer plate, each of the lands having a relatively rectangular shape and having a thickness less than a thickness of the vertical seals on the series of horizontally disposed adjoining pouches, the plurality of lands being pivotally mounted at an upper end along the outer edge of the land plate allowing each of the lands to freely pivot radially inward and extend vertically downward from the land plate, the plurality of lands being equally spaced about the circumference of the land plate wherein the distance between each land is equivalent to the distance between the vertical seals on the series of horizontally disposed adjoining pouches, whereby when the horizontally disposed adjoining pouches are trained onto the horizontal rotary sealer to join and seal the upper portion of the adjoining pouches, the vertical seals extending below the top edge of the pouches will engage with the lands and curve radially inward in engagement with the lands, thereby helping to keep the horizontally disposed adjoining pouches properly aligned; and g) wherein the horizontal rotary sealer further includes at least one press roller mounted for counter-rotation in pressing engagement against the rotating circumference of the heated circular sealer plate in order to help seal and align the top edge of the web of horizontally disposed pouches.
  • 47. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material; and f) sealing the top edge of each pouch together to close the filled pouches by training the pouches onto a horizontal rotary sealer, said horizontal rotary sealer having a heated circular sealer plate and vertical alignment means, said vertical alignment means allowing the opposed sidewalls of each filled pouch to remain in alignment with the vertical regardless of the quantity of material used to fill each of said pouches, progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be joined together and smoothly sealed to enclose the filled pouches.
  • 48. A method of forming a horizontal top seal for use in a packaging machine having a continuous web of film material having a series of horizontally disposed filled pouches separated by vertical seals extending transversely of the web and having opposed sidewalls of each pouch unsealed along a top edge, the method comprising training the horizontally disposed filled pouches onto a horizontal rotary sealer said horizontal rotary sealer having a heated circular sealer plate and vertical alignment means, said vertical alignment means allowing the opposed sidewalls of each filled pouch to remain in alignment with the vertical regardless of the quantity of material used to fill each of said pouches, progressively forming a continuous horizontal seal as the top edge of each pouch is being continuously moved along with a circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edge of each pouch to be gently joined together and smoothly sealed to enclose the filled pouches.
  • 49. A packaging apparatus, comprising:a) means for feeding a continuous web of film material having confronting sides; b) means for forming vertical seals in the web to form a series of horizontally disposed pouches separated by the vertical seals, the vertical seals extending transversely of the web from a bottom edge of the pouch to an upper portion of the pouch; c) means for opening the pouches by separating opposed sidewalls of the pouches; d) means for filling the pouches with a material to form outwardly bulged sidewalls; and e) a horizontal rotary seal former having a heated circular sealer plate mounted for rotation and a vertical alignment means, the heated circular sealer plate having a flat outer surface positioned about its circumference for engagement with an upper portion of the pouches for progressively forming a continuous horizontal seal as the web is being continuously moved along with the circumference of the heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed, said vertical alignment means allowing the opposed sidewalls of each filled pouch to remain in alignment with the vertical regardless of the magnitude of the outward bulge of the sidewalls of each of said pouches.
  • 50. A horizontal seal former device for use with a continuous web of film material having confronting sides and a series of horizontally disposed filled pouches defined by a series of vertical seals extending transversely of the web from a bottom edge of the pouch to an upper portion of the pouch, the device comprising: a top seal shaft, said top seal shaft being connected to a rotating means for rotating said top seal shaft, a heated circular sealer plate mounted for rotation on said top seal shaft, said circular sealer plate having an upper portion comprising a flat outer surface positioned about its circumference for engagement with an upper portion of a continuous web of filled pouches for progressively forming a continuous horizontal seal as the web is moved along with the rotating circumference of the flat outer surface while at the same time applying an adequate temperature to provide a sealing action and allowing the upper portion of the pouches to be joined together and smoothly sealed to enclose the filled pouches, said circular sealer plate having a lower portion comprising a vertical alignment means, said vertical alignment means allowing said filled pouches to remain in a vertical orientation adjacent to the circular sealer plate regardless of the extent of bulge of the filled pouches.
  • 51. A method of continuously forming, filling and sealing of packages with a continuous web of film material, comprising the steps of:a) providing a continuous web of film material; b) folding the web to provide confronting sides joined along a bottom edge; c) forming a vertical seal at spaced intervals along the web thereby providing a series of horizontally disposed adjoining pouches having opposed sidewalls with each pouch unsealed along a top edge; d) opening the pouches by separating the opposed sidewalls; e) filling the pouches with a material to form outwardly bulged sidewalls; and f) radially and circumferentially moving the open filled pouches in union with a circumferentially moving heated circular sealer plate while at the same time applying an adequate temperature to provide a sealing action and allowing the top edges of each pouch to be joined together and smoothly sealed to enclose the filled pouches, said moving heated circular sealer plate also comprising a vertical alignment means, said vertical alignment means allowing the opposed sidewalls of each filled pouch to remain in alignment with the vertical regardless of the magnitude of the outward bulge of the sidewalls of each of said pouches.
US Referenced Citations (30)
Number Name Date Kind
2655777 Hagen Oct 1953
3158973 Monaghan Dec 1964
3237371 Gerlach Mar 1966
3328936 Billeb Jul 1967
3505776 Cloud Apr 1970
3552088 Niwa Jan 1971
3597898 Cloud Aug 1971
3720565 Cavanna Mar 1973
3995407 Segale et al. Dec 1976
4219988 Shanklin et al. Sep 1980
4232504 Dieterlen et al. Nov 1980
4288967 Seko et al. Sep 1981
4344269 Dieterlen et al. Aug 1982
4380446 Dickson et al. Apr 1983
4597240 Scully Jul 1986
4696147 Noh Sep 1987
4712357 Crawford et al. Dec 1987
4783950 Santagati Nov 1988
4798038 Litt Jan 1989
4858416 Monaghan Aug 1989
4909356 Rimondi et al. Mar 1990
4914889 Francioni Apr 1990
4924657 Berti et al. May 1990
4945709 Cerf Aug 1990
5174088 Focke et al. Dec 1992
5184447 Johnsen Feb 1993
5335478 Aronsen Aug 1994
5502952 Wildmoser Apr 1996
5699653 Hartman et al. Dec 1997
5875610 Yuyama et al. Mar 1999