US 3546849 A
Description (OCR text may contain errors)
1366- 1970 D. D. ZIMMERMAN PACKAGING MACHINERY 2 Sheets-Sheet 1 Filed Jan. 22. 1968 INVENTOR. ZAE/d/A/ D Z/MMflMA/l BY Wm,
1970 .D. D. ZIMME-RMAIN PACKAGING MACHINERY 2 Sheets-Sheet 2 Filed Jan. 22. 1968 INVENTOR. DA EdJ/A/ D Z/A/MEZMAA/ BY Z/JAMflM-Z A TT'OEK EVS United States Patent U.S. Cl. 53-373 8 Claims ABSTRACT OF THE DISCLOSURE A packaging machine having an elongated cutofr knife housed within one of a pair of oppositely disposed, rotatable sealing dies, and an actuating mechanism operative to intermittently move the knife through a continuous length of wrapping material between spaced apart articles enclosed therein into a receiving slot on the other one of the sealing dies. The same epicyclic gear train which drives the sealing dies at a non-uniform speed is arranged to operate the knife-actuating mechanism in such a way that the knife cuts through the wrapping material in a rapid, slicing motion when the sealing dies are in engagement with opposite sides of the wrapping material during a crimping and sealing operation. The non-uniform rotational speed of the sealing dies may be adjusted in order to compensate for different lengths of articles to be packaged in the wrapping web by rotating an adjustment shaft housed concentrically within the main power input shaft, the movement of the adjusting shaft serving to change the eccentric disposition of the main drive gear of the epicyclic gear train with respect to the power input shaft to which it is connected.
BACKGROUND OF THE INVENTION Packaging machines of the type in which articles to be wrapped are entubed in a continuous, moving length of wrapping material have conventionally employed rotary sealing and cutoff dies which operate to seal and sever the wrapping material between adjacent articles. The use of rotary cutting dies is disadvantageous in that the complementary cutting dies disturb the simultaneous sealing of the wrapper ends by the sealing dies if not adjusted properly. Also, the pressure cutting action resulting from the gripping of the ends of the wrapping web between the mating surfaces of the rotating cutting dies does not provide a positive, sharp, cutoff of the Wrapping web. Moreover, the use of rotary cutoff dies which roject radially outwardly beyond the crimping and sealing dies in the manner shown in US. Pat. No. 2,546,721 necessarily limits the length of wrapper ends which may be pressure-sealed together by the sealing dies before the projecting cutting dies engage the wrapper.
Another problem associated with prior art wrapping machines of the aforesaid type relates to the adjustments required in the operation of the crimping, sealing, and cutoff dies in order to compensate for changes in length of the articles being packaged. The crimping and sealing dies are in many cases driven by a gear train employing an eccentric gear which serves to impart an irregular, angular velocity to the dies. This is done so that the dies will be rotating at a relatively high speed corresponding to the lineal speed of the wrapping web at the time of crimping and sealing, and de-accelerate thereafter so as to again engage the wrapping web only after an article has passed. Thus, when the length of the articles to be packaged changes, then the angular velocity of the crimping and sealing dies must be adjusted accordingly, in order to insure that they will engage the wrapping web between adjacent articles. In the past, such speed adjustments have 3,546,849 Patented Dec. 15, 1970 BRIEF ,SUMMARY OF THE INVENTION Having in mind the foregoing difficulties associated with prior art packaging machines, I have developed a new machine which is particularly characterized by a guillotine type of cutoff knife which provides a sharp, quick cutting action, and which does not depend upon pressure for its operation.
The cutoff knife is advantageously housed within a recess in one of the rotary sealing dies, and is received within a complementary recess or slot in the other one of the sealing dies when it cuts through the wrapping web. The knife is preferably in the form of an elongated, sharpedged member which is moved through the wrapping material in a guillotine-like severing motion when the crimping and sealing dies are in a predetermined position in engagement with the wrapping web.
A particularly beneficial aspect of my invention resides in the operation of the cutting knife by the same gear train which drives the rotary sealing dies in such a way as to coordinate the cutting movement of the knife with the desired angular disposition of the sealing dies with respect to the wrapping web. This is accomplished by means of an actuating mechanism which includes a cam mounted on one of the sealing die shafts and a cam follower connected to pivotal links attached to the cutting knife, whereby the displacement of the cam follower by the cam when the sealing dies have reached a predetermined rotational position causes the cutting knife to move downwardly through a horizontally moving wrapping web in a sharp, penetrating cutting motion.
As a further advantageous feature of my invention, I have provided an adjustment mechanism by means of which the rotational speed at which the crimping and sealing dies are driven may be easily changed without stopping the operation of the packaging machine. An actuating shaft for the gear adjustment mechanism is disposed concentrically within the main power input shaft and is rotatable with respect thereto in such a way as to change the eccentric disposition of the main drive gear with respect to the power input shaft to which it is connected. A mounting shaft for the eccentric drive gear is movable back and forth on a threaded member which can be rotated by a pair of bevel gears driven by the aforesaid actuating shaft.
These and other objects and advantages of my invention will become readily apparent as the following description is read in conjunction with the accompanying drawings, of which:
FIG. 1 is a front, elevation view of the packaging machine of this invention;
FIG. 2 is a side elevation view of the machine of FIG. 1;
FIG. 3 is a vertical section view taken along lines 33 of FIG. 1;
FIG. 4 is a partial end view taken along lines 4-4 of FIG. 1;
FIG. 5 is a vertical, section view taken along lines 5-5 of FIG. 2;
FIG. 6 is a fragmentary, perspective view showing the adjustment mechanism for the gear train; and
FIG. 7 is a horizontal, section view of the adjusting and locking knob portion of the gear speed adjusting mechanism taken along lines 7-7 of FIG. 1.
The packaging machine of which this invention forms a part conventionally includes conveyor means for propelling a continuous web of wrapping material over a forming die so as to shape the web in the form of an elongated tube within which articles fed in by a separate conveyor are enclosed in spaced apart relationship. These preliminary steps have not been illustrated as they form no part of this invention. The wrapping Web with the entubed articles to be packaged, such as candy bars, is then conveyed to a sealing and cutoff station at which the ends of the wrapping material between adjacent articles are sealed together and cut off. A sealing die assembly incorporating the improved cutoff arrangement of my invention is indicated generally by reference numeral 1 in FIGS. 1 and 2. The assembly is supported on upright members 2 and 3 on which horizontal beams 4 and 5 are supported. Vertical frame members 6, 7, 8 and 9 (not shown) extend upwardly from horizontal beams 4 and 5, and transverse bearing blocks 10, 12, 14, and 16 are fastened thereto. Upper shaft 18, which is rotatably mounted between bearing blocks and 12, supports a first crimping and sealing die 20. A mating crimping and sealing die 24 is fastened to lower, rotary shaft 22.
Rotary motion is imparted to shaft 22 by means of an epicyclic gear train having a main, eccentric drive gear 24 which is rigidly secured to stub shaft 26. Hub 26 serves to drivingly connect main power input shaft 30 to stub shaft 26 in a manner more fully explained below. It is sufficient to note at this point that stub shaft 26 and input or drive gear 24 are disposed eccentrically with respect to rotary power shaft 30, thereby causing eccentric gear 24 to move in an orbit as shaft 30 rotates. Link 32 is rotatably supported by means of collar 33 on bearing 34 secured to stub shaft 26. The other end of link 32 is rotatably mounted on floating stub shaft 36 by means of bearing 38. A second gear 40 having its teeth enmeshed with the teeth of eccentric drive gear 24 is rotatably supported on floating stub shaft 36. The teeth of gear 4% are also in driving engagement with the teeth of gear 42 which is supported for rotational movement on stub shaft 44. Bearing 46 on shaft 44 pivotally supports a second link 49 which is connected at its outer or lower end to bearing 38 on shaft 36. An eccentric drive gear 24 orbits in the clockwise direction indicated by the arrow in FIG. 2, the number of its teeth meshing with the teeth on gear 40, and the point of mesh, constantly changes; and, therefore, the angular velocity at which gear 40 is driven by gear 24 varies within each revolution of gear 24. Also, interconnecting link 32 causes gear 40 to oscillate back and forth as gear 24 orbits, and the relative angular disposition of link 32 and 49 will change from the acute angle shown in FIG. 2 to an obtuse angle when gear 24 is at the bottom, of its orbit in the phantom line position shown. As gear 24 orbits downwardly it drives gear 40 at an increasing angular speed due to the increase in the number of teeth meshing; and, as gear 24 orbits upwardly it drives gear 40 at a decreasing speed. Since gear 40 is constantly enmeshed with gear 42, its changing angular velocity will be reflected in a corresponding constant change in the angular velocity of gear 42. As gear 40 moves to the left, it drives gear 42 at an increasing rotational speed because of the change in the point of mesh of the teeth of the two gears. Gear 40 will be rotating at an increasing or accelerated angular speed as it moves to the left because eccentric drive gear 24 is moving downwardly at that time; therefore, the angular speed of gear 42 will also be accelerating at this time. correspondingly, as gear 40 moves to the right, it will drive gear 42 at a decreasing rotational speed.
The rotation of gear 42 by the aforesaid epicyclic gear train will result in the rotational movement of lower shaft 22 to which gear 42 is rigidly attached. Pinion gear 48 on shaft 22 will in turn drive enmeshed pinion 50,
thereby causing the rotation of upper shaft 18 in a counter-clockwise direction. By virtue of the above-described epicyclic gear drive arrangement, shafts 18 and 22 and dies 20 and 24 mounted thereon will rotate at constantly changing angular velocities. Crimping and sealing dies 20 and 24 are so located on shafts 18 and 22 that they will be rotating at a maximum speed when they are in the position shown in FIG. 1 directly opposite each other in face-to-face engagement with the wrapping web; and, they will then rotate at a decreasing speed so that the article to be packaged may pass completely by them before they again engage the wrapping web.
After the web of wrapping material has been crimped and sealed between adjacent articles in the manner indicated in FIG. 3, it is necessary to cut the web so that the ends of the separate packages may then be tucked and sealed against the package in a subsequent operation. For the purpose of carrying out this web-cutting operation, I have provided a unique arrangement utilizing an elongated knife 52. Referring now to FIGS. 1, 3 and 4, it will be seen that knife 52 is mounted transversely with respect to the path of movement of wrapping web 54 (FIG. 3), and is normally contained within slot 56 in upper sealing die 20. Links 58 and 60 which are pivotally secured within elongated recess 59 of upper sealing die 20 support knife 52. Spring 62 acting against ring portion 64 of knife handle 66 serves to bias links 58 and 60 towards the position in which they are shown in FIG. 1 wherein they hold knife 52 in retracted position within slot 56 of die head 20. In order to actuate knife 52 so that it will cut through wrapping web 54 at the desired time in the proper manner, I have provided a unique actuating mechanism comprised of cam holder 68, cam 70 and cam follower 72. Cam holder 68 is fastened to shaft 22 for rotational movement therewith, and cam follower 72 is attached to pivotal link 58. As may be best understood with reference to FIGS. 1 and 3, cam 70 will periodically strike cam follower 72 as cam holder 68 rotates with shaft 22, thereby displacing cam follower 72 upwardly and causing links 58 and 60 to pivot to the phantom line position shown in FIG. 1. As links 58 and- 60 pivot downwardly, knife 52 will move laterally and downwardly through wrapping web 54. As knife 52 severs web 54 it will pass into receiving slot 74 in lower sealing die 24. The angular disposition of cam 70 on cam holder 68 is selected so that cam 70 will strike cam follower 72 and actuate knife 52 so as to sever Web 54 at the precise instant that sealing dies 20 and 24 are directly opposite each other in sealing engagement with opposite faces of web 54. The initiation of the cutting action of knife '52 in this manner provides several advantages. First of all, it insures the positioning of slot 56 and complementary slot 74 directly opposite each other at the time of cutting so that knife 52 will be properly received within lower slot 74. Secondly, since cam 70 will engage cam follower 72 as dies 20 and 24 reach maximum rotational speed for sealing engagement with moving web 54, cam 70 will also be rotating at a relatively high angular velocity, thereby bringing about the very rapid cutting action and subsequent retraction of knife 52. Knife 52 thus moves through wrapping web 54 with a sharp, swift, guillotine type of cutting stroke, thereby cleanly cutting the wrapping web without interfering with the sealing action of dies 20 and 24. The cutting action of knife 52 is further improved by causing it to move through web 54 at the instant that the web is held tightly between sealing dies 20 and 24.
Knife 52 is preferably provided with a sharp, scalloped bottom edge to enhance its cutting action. Also, knife 52 is positioned off-center within slot 56 so that as it moves downwardly to complementary slot 74 it will cooperate with back wall 73 thereof in sliding contact therewith so as to provide a desirable shearing action. This disposition of knife 52 with respect to back wall 73 of slot 74 is best shown in FIG. 3.
Those skilled in the packaging machinery art will read ily appreciate that the penetrating, guillotine-like cutting action of knife 52 represents a distinct improvement over the pressure type of rotary cutting dies heretofore available. Not only does guillotine knife 52 provide better cutting action, but also it insures a minimum of interference with the pressure sealing of the ends of web 54 by eliminating inwardly projecting cutoif dies which rely on pressure to sever the wrapping web. Knife 52 is also relatively simple and economical to replace, and its adjustment within upper sealing die is not critical. Rotary cutting dies suffer from the disadvantage that if they are not adjusted correctly so as to project radially inwardly the proper distance, they will interfere with the simultaneous pressure sealing of the rotary sealing dies to which they are secured. It is to be noted that the gear train utilized to rotate the shafts 18 and 22 may be employed to operate knife 52 through some mechanism other than cam 70" and cam follower 72. The primary consideration is that the cutting stroke of knife 52 be coordinated with the angular disposition of sealing dies 20 and 24 so that the severing of web 54 takes place when the sealing dies are in the desired, predetermined position directly opposite each other.
For purposes of my invention, the particular manner employed for sealing the opposite faces of wrapper web 54 together between adjacent wrapper sections is of no particular significance. An adhesive material may be employed to seal the Wrapper web as it is pressed between the oppositely disposed faces of sealing dies 20 and 24 in the manner indicated in FIG. 3, or the well known heat sealing method may be utilized. I prefer to employ the latter mode of sealing, and to that end electric heating elements 76 and 78 are inserted within rotary shafts 18 and 22 on which sealing dies 20 and 24 are mounted. The wrapper engaging faces of dies 20 and 24 may be knurled or roughened so as to permit them to crimp the wrapper at the same time that it is sealed. However, for purposes of this invention it is immaterial whether the wrapping web is crimped as well as sealed.
As was noted above, the angular velocity of sealing dies 20 and 24 must be adjusted within a particular packaging cycle so that their rotational speed will be equal to the linear speed of the wrapping web during the sealing op peration, and so that they will complete a revolution and re-engage the wrapping web after a wrapped article has been passed between them. Thus, with input drive sprocket 80 rotating power input shaft 82 at a particular speed, the eccentric disposition of drive gear 24 with respect to shaft 30 must be adjusted so that rotary sealing dies 20 and 24 will accelerate and de-accelerate at the desired rate, taking into consideration the linear speed at which wrapping web 54 is moving and the length of the articles to be packaged. It will be readily appreciated that the greater the distance by which stub shaft 26 is offset with respect to the center of power input shaft 30 the greater will be the variation in angular velocity at which drive gear 24 rotates gear 40. Thus the variable angular velocity at which sealing dies 20 and 24 are rotated may be adjusted so as to compensate for changes in the length of the articles to be packaged by changing the eccentric displacement of stub shaft 26 with respect to power input shaft 30. In the past, such speed adjustments have necessitated the stopping of the packaging machine as well as relatively complicated changes in the gear drive mechanism, including the changing of gears and/or cams, depending upon the particular type of drive arrangement employed. I have overcome this speed adjustment problem by utilizing a relatively simple connecting device between stub shaft 26 and power input shaft 30 which permtts the radial displacement of shaft 26 with respect to shaft 30 to be adjusted while the packaging machine is running. With reference to FIGS. 5 and 6, my unique, adjustable connecting means for stub shaft 26 is comprised of the assembly of cylindrical hub 28, guide member 82 fastened to the front face thereof, and elongated, threaded member 90 which extends vertically through guide member 82. Guide member 82 is provided with a vertical slot 84 which accommodates square end portion 86 of stub shaft 26. Elongated screw 90 extends through threaded aperture 88 in end portion 86 of stub 6 shaft 26, thusserving to connect shaft 26 to the assembly of guide member 82 and hub 28 for rotational movement therewith. Hub 28 is rigidly fastened to power input shaft 30, and thus the entire assembly of shaft 30, hub 28, guide member 82, threaded screw 90, and stub shaft 26 with eccentric gear 24 mounted thereon rotates as a single unit.-
The eccentric location of stub shaft 26 with respect to the center of input shaft 30 will cause gear 24 to revolve in an orbit in the manner indicated in FIG. 2. Stub shaft 26 can be moved up and down within slot 84 by rotating screw member 90 with which it is threadedly engaged. Miter gear 92 mounted on the lower end of screw 90 will turn screw member 90 when driven by mating miter gear 94 which is rigidly attached to adjusting shaft 96 for rotational movement therewith. Adjusting shaft 96 extends longitudinally within power input shaft 30 and may be rotated by means of adjusting knob 98 at its outer end, shown in FIGS. 1 and 7. Enlarged, keyhole portion of slot 84 accommodates miter gear 92. In order to adjust the angular velocity of sealing dies 20 and 24 to compensate for a variation in the length of the articles to be packaged, it is only necessary to turn knob 98 in the necessary direction to move stub shaft 86 up or down within slot 84. Miter gear 94 on adjusting shaft 96 will rotate miter gear 92 and screw 90, thereby causing stub shaft 26 to move vertically within slot 84 on screw to a new radial distance from input shaft 30. By thus changing the eccentric location of drive gear 24 with respect to input shaft 30, the number of teeth on gears 24 and 40 meshing at any given instant will be changed with the result that gear 40 will rotate within a different range of angular velocities. A corresponding change in the rotational speeds of sealing die shafts 18 and 22 will of course be realized. This speed adjustment may be advantageously carried out while the packaging machine is running and input shaft 30 is rotating, without the aid of wrenches or special tools of any kind.
Once stub shaft 26 for drive gear 24 has been adjusted to the desired eccentric position, bevel gears 94 and 92 may be locked by means of shaft 100 and lock knob 104 to insure that shaft 26 is not moved out of position. Locking shaft 100 is slidable within adjusting shaft 96 and extends concentrically therethrough, as is indicated in FIGS. 5 and 7. As shaft 100 is drawn to the right by the tightening of threaded lock knob 104 thereon against knob 98, head 102 on shaft 100 clamps miter gear 94 tightly against hub 28. In this locked position, miter gears 92 and 94 will rotate as a unit with hub 28. The loosening of lock knob 104 will free miter gears 94 and 92 so that they can be turned by adjusting shaft 96 when it again becomes necessary to adjust the speed of die shafts 18 and 22.
While I have described my improved packaging machine with respect to the particular embodiments of the cutoff knife and speed adjusting mechanism shown, I do not intend that my invention should be limited thereto. I contemplate that various changes may be made without departing from the spirit and scope of my invention as defined by the following claims.
What I claim is:
1. In a packaging machine having a station at which a moving, formed wrapping web enclosing spaced apart articles is sealed and cut off between adjacent articles, the improvement comprising:
a pair of rotatably mounted sealing dies;
drive means for imparting rotational movement to said sealing dies;
a cut off knife in the form of an elongated blade disposed transversely of the path of travel of said wrapping web; and
an actuating mechanism connected to said knife and operable to move said knife through said wrapping web in a cutting motion, said actauting mechanism including a portion thereof operatively associated with said drive means in such a way as to initiate said cutting motion of said knife in response to the movement of said drive means when said sealing dies are rotated to a predetermined position with respect to said wrapping web, said actuating mechanism further including pivotal linkage elements connected to said knife, the pivoting of said elements in response to the movement of said portion of said actuating mechanism operating to move said knife through said web.
2. In a packaging machine having a station at which a drive gear constituting an element of said gear train;
a rotary, power input shaft;
mounting means connecting said drive gear to said power input shaft eccentrically with respect thereto;
a moving, formed wrapping web enclosing spaced apart articles is sealed and cut off between adjacent articles, the improvement comprising:
an adjustment mechanism connected to said drive gear and operative to change the radial displacement of said drive gear with respect to the center of said a pair of rotatably mounted sealing dies; drive means for imparting rotational movement to said power input shaft ;and an elongated actuating member extending through said sealing dies; power input shaft and movable with respect thereto, a cut off knife disposed transversely of the path of travel said actuating member being connected to said adof said wrapping web; and justment mechanism, and the movement of said acan actuating mechanism connected to said knife and actuating member within said power input shaft servopera le to m v said knife thmugh Said W apping ing to actuate said adjustment mechanism and thereby web in a cutting motion, said actuating mechanism adjust the eccentric disposition of said drive gear including cam means mounted for rotational movement by said drive means and cam follower means adapted to be engaged by said cam means when said sealing dies are rotated to a predetermined position with respect to said power input shaft.
6. Packaging apparatus as defined in claim 5, wherein said adjustment mechanism comprises:
a rotatable, threaded member angul-arly disposed with with respect to said wrapping web, the engagement respect to said ower input shaft; and displacement of said cam follower means by said a h ft member connected to said drive gear and excam means initiating the cutting motion of said knife tending substantially parallel to said power input and causing said knife to m ve rough s d Wrapshaft, said shaft member and said rotatable, threaded ping web. member being in threaded engagement; and 3. Packaging apparatus as defined in claim 2, wherein: means driven by said actuating member for rotating said sealing dies are secured to separate shafts which said threaded member.
are rotated by said drive means, and Wh 7. Packaging apparatus as defined in claim 6, wherein: said cam means is mounted on one of said shafts in such said actuating member is rotatably supported within a position that it engages said ca-m follower means said power input shaft; and and moves it to a position of maximum displacement said means for rotating said threaded member comas said sealing dies are rotated to said predetermined prises a pair of bevel gears, one of which is mounted position directly opposite each other in engagement on said threaded member and the other of which is with opposite surfaces of said wrapping we-b. mounted on said actuatingmember. 4. In a packaging machine having a station at which a 8. Packaging apparatus as defined in claim 5, wherein moving, formed wrapping web enclosing spaced apart arsaid mounting means includes:
a stub shaft to which said drive gear is rigidly secured;
ticles is sealed and cut off between adjacent articles, the i a guide member having a slotted portion in which one improvement comprising:
a pair of rotatably mounted sealing dies; drive means for imparting rotational movement to said end of said stub shaft is slidably received, said slotted portion extending angularly with respect to said power sealing dies; input shaft; and a cutoff knife disposed transversely of the path of travel means Connecting Said Stub shaft to Said j m n of id Wrapping b; d mechanism whereby the operation of said adjustment an actuating mechanism connected to said knife and mechanism y S a i g member moves said o er ble t o aid k if th o h id wrapping stub shaft back and forth within said slotted portion web in a cutting motion, said actuating mechanism so as to Change the ecfientr'ic Position of Said drive including a portion thereof operatively associated gear with respect to Sald Power input Shaftwith said drive means in such a way as to initiate said cutting motion of said knife in response to the move- References Cited ment of said drive means when said sealing dies are UNITED STATES PATENTS rotated into alignment with each other and engage 2,950,538 8/1960 Gausman Sa1d W p Web therebetweer}; u W r r 3 20,72 5 7 Murray sa d drive means comprises anepicyclic gear train ar- 3,433,173 4/1969 Omori ranged to impart maximum rotational speed to said sealing dies and to said portion of said actuating mechanism when said sealing dies engage said wrapping web.
5. In a packaging machine having rotatably mounted sealing dies driven at a non-uniform speed by a gear train US. 01. X.R. 53182, 201