US2837012A - Scoring apparatus - Google Patents

Description

June 3, 1958 E. E. BURROUGHS SCORING APPARATUS 3 Sheets-Sheet 1 Filed Nov. 30, 1954 INVENTOR Pk- I 4a ATTORNEYS.

EDWIN E. BURROUGHS.

June 3, 1958 E. E. BURROUGHS 2,837,012

SCORING APPARATUS Filed Nov. 50, 1954 3 Sheets-Sheet 2 IN V EN TOR.

EDBVJIN E BU/PRO us HS.

J; ATTORNEYS:

June 3, 1958 E. E. BURROUGHS 2,837,012

SCORING APPARATUS Filed Nov. 30. 1954 I 3 Sheets-Sheet 3 ELLIPTICA L Gen Rs INVENTOR. [ow/1v EBUEEOUGHS.

4;; ATTORNEYS.

United States Patent SCORING APPARATUS Edwin E. Burroughs, Pensacola, Fla., assignor to St. Regis Paper Company, New York, N. Y., a corporation of New York Application November 30, 1954, Serial No. 472,057

2 Claims. (Cl. 93-8) This invention relates to apparatus for scoring workpieces of sheet material, and more particularly to apparatus for forming transverse score lines in a succession of bag tubes of paper or the like sheet material.

The invention is well adapted, among other purposes, for use as a part of a bag bottom forming apparatus for forming the base score lines transversely of and near the opposite ends of flattened bag tubes which are conveyed in a direction transverse to the sides thereof.

Bag tube scoring apparatus heretofore proposed has generally been of the rounded disc variety, including a pair of discs, one of which has a peripheral groove which cooperates with a peripheral score blade or tongue formed on the other disc. This particular type of scoring device has not proven entirely satisfactory in the past because of the lack of versastility thereof with respect to its applicability to a wide variety of bag tubes. That is, the round disc type of scorer has required special configuration and special adjustment for each type of bag tube which is scored. Such types of bag tubes are normally determined by the unit weight of the paper, such as kraft, and also the number of plies of paper. A particular round disc type of scorer may be designed for a given type of bag tube and may perform substantially satisfactorily for such given type. However, it has been observed that despite the designing of such a rounded disc type of scorer for a particular type of bag tube, it is not fully reliable in that some of the score lines will be curved and consequently will produce difficulties in the folding of the bag tube and hence lead to the formation of defective bag bottoms.

Furthermore, bag scoring devices heretofore suggested of the aforementioned disc variety cannot, without sub stantial difficulty, be employed for scoring bag tubes other than those for which originally designed, and as aforementioned, even when working upon the tubes for which they were originally. intended, the accurate forming of the score lines is unreliable.

One of the objects of the present invention is to overcome the above difficulties or to reduce same to insignificance.

The invention in one aspect is constituted by the following combination. Conveyor means are provided for conveying a succession of bag tubes along a common path and at a common interval. Such conveyor means moves the bag tubes successively along a common, prefably horizontal, plane and successively past a bag tube scoring station. At such scoring station there is situated a pair of score bars which are respectively provided with a groove and a score blade and which are brought together periodically in close parallel relationship thereby successively to press each bag therebetween and to form ascore line transversely thereof extending in a direction parallel to the direction of the conveyor. Each of said score bars is mounted upon a pair of substantially parallel rotatable cranks, each score bar thereby comprising a connecting rod of a parallel crank four-bar linkage.

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The rotatable cranks of each of such linkages are operatively interconnected to bring the score bars into bag tube scoring cooperation, once for each revolution of a crank. The region of each bag which is to be scored normally moves in the aforementioned plane along its path of movement and such plane is referred to as the scoring plane. In order to maintain the desired phase relation ship between the score bars and the oncoming bag tubes and at the same time to bring the linear speed of said score bars into synchronism with the linear speed of the conveyor and hence the bag tubes, 1 have found it desirable cyclically to vary the angular speed of the cranks of said four-bar linkages by any suitable means whereby the score bars are increased in linear velocity as they approach each moving bag tube and reach maximum linear speed during the pressing of the tube therebetween, such maximum linear speed being synchronized with the linear speed of the conveyor, and hence of the bags.

Various, further and more specific objects, features and advantages of the invention will clearly appear from the detailed description given below taken in connection with the accompanying drawings which form a part of this specification and illustrate, by way of example, a preferred arrangement of apparatus for carrying out the invention. The invention consists in such novel combinations of features as may be shown and described in connection with the apparatus herein disclosed.

In the drawings:

Fig. 1 is a perspective view illustrating schematically one form of apparatus embodying the invention;

Fig. 1a is a schematic illustration of a pair of linkages employed for mounting and moving the scoring device of the present invention;

Fig. 2 is a side elevation of the principal portions of the apparatus of Fig. 1 but in a different operating position;

Fig. 3 is a side elevation on a relatively enlarged scale, as compared to Fig. 1, of a scoring unit embodying the present invention;

Fig. 4 is a plan View of the apparatus shown in Fig. 3;

Fig. 5 is a fragmentary view on an enlarged scale, partly in section and with parts broken away, taken trans versely of the parallel scoring bars during scoring cooperation therebetween;

Fig. 6 is an end view of a gear train, including a pair of elliptical gears employed for cyclically varying the speed of the scoring means.

Referring to the drawings in greater detail, with particular reference to Figs. 1, 1a and 2, the novel apparatus is shown in an environment for forming score lines upon flat sheet-like workpieces, such as bag tubes, such score lines extending in the direction of the motion of a con about which the opposite end portions of the bag tube can be bent at to the plane of the main body of the bag.

The ends of the bag tubes so bent at 90 thereafter are operated upon by other devices for forming the bag bottoms.

In Fig. 1 a conveyor 10 is provided for conveying a succession of bag tubes along a common path and at a constant selected interval. Two of such bag tubes are shown illustratively at 11 and 12. The conveyor 10 preferably comprises, in a conveying device of this particular variety used in the bottoming of bag tubes, a pair of parallel endless sprocket chains 13 and 14 which, at their opposite extremities, respectively pass over sprocket wheels 15, 16 and 17, 18. A plurality of cooperating pairs of bag tube clamps are positioned on said chains 13 and 14, for example, a clamp 19 on chain 13 cooperates -2,sa7,01 a

with a clamp 20 (in chain 14 for clamping and pulling the bag tube blank 11 in the direction of arrow 21. And a clamp 22 on chain 13 cooperates with a clamp 23 on chain 14 for the same purpose. The interval between the two pairs of clamps 1 9 20 and 22', 23' is indicated by the distance or interval y and is common between all of such pair's ofclarhps as measured along the" length thereof. Itis' of course, understood that other pairs of bag clamps, such as 24, 25, are provided also spaced at the common interval from its next adjacent pair of clamps. The two chains 13 and 14 may be laterally separable by suitable means as shown in my copending application'- Serial- No. 422,575;

The sprocket wheels 15, 16 and 17, 18 are driven together preferably by rigidly interconnecting the driving shaftsthereof or by employing a common driving shaft for such sprocket wheels.

. As aforementioned, in order to assist in the bag bottom forming operation, it is desired to bend upwardly at a 90 angle from the main bag body, for example, the end portions 12a and 12b of each bag tube. Such bending is accomplished by suitably shaped end bending strips, such as 26, which cooperates with a strip 27, as shown in Fig; 1. It is, of course, understood that the bag tubes, suchas 1'1 and 12 are supported therebeneath by suitable flooring which may extend the length of the conveyor and which has suitably positioned slots for the movement. of the conveyor chains 13 and 14 and also for accommodating the novel scoring apparatus to be described hereinafter.

The folding of the aforementioned end portions 12a and 12b can thus be facilitated by preliminarily forming mainscore' lines transversely near each of the ends of the bag tube, such score lines being indicated at 28 and 29 on the bag tube blank 12.

Referring to the bag tube .11 (Fig. 1), the proposed location of proposed score lines which correspond to the aforementioned score lines 28 and 29 (on bag 12), are, shown by the broken lines 30 and 31 respectively near the left and righthand end margins of the bag tube 11 but each; being spaced therefrom by a selected dimension.

There will now be described the novel straightline scoring device for effecting the aforementioned score lines in succession as each bag tube passes ab'ag scoring station,. such station, of course, generally being the location of the bag scoring device. Only one such novel scoring device is to be described, it being. indicated generally at 32, it being understood that on the opposite side of the conveyor an analogous bag scoring device is employed for forming a score line along the location indicated by broken line 31.

A pair of straight score bars 33 and 34 are employed in the scoring device 32 for forming a score line along the broken line 30. Such score bars 33 and 34 are well shown in cross section in Fig.5 and comprise respectively an elongated element, including a score blade 35 which is held by the bar 33 for periodic scoring cooperation with a groove 36 formed along the upper face of the score bar 34. The edge of the score blade 35 is preferably rounded'to avoid cutting through the paper of the bag tube. However, it is within the purview of the invention to perform other than a scoring function upon the bag tube. For example, aweakening line may be formed along the broken lines 30 and 31 in lieu of the score line. The term score line as employed herein refers to a line about which the paper can be bent easily. However, the score blade, if desired, may be conformed to make intermittent and spaced short cuts through the paper separated by portions which are uncut.

. The elongated score bars 33 and 34, in the form shown, extend in a direction parallel to the direction of motion of the conveyor 10 and are so moved, as will appear below, that when in contact with :a bag tube they are proceeding in the same direction therewith and at the same speed.

It is desirable to move the score bars 33 and 34 in true parallel relationshipinto scoring cooperation with the end of the bag interposed therebetween. I have found an advantageous means for so moving the score bars to be a pair of parallel equal crank four-bar linkages well illustrated schematically in Fig. 1a, the score bars 33 and 34 comprising respectively the connecting rods of their linkages. The uppermost of such parallel equal crank four-bar linkages will now be described, the score bar 33 comprising the connecting rod therefor: A pair of cranks 37 and 38 are provided which are mounted upon suitable shafts, the latter being Well illustrated at 37a and 38a (.Fig. 3). The score bar 33 is also represented in Fig. In by the bar AB, the cranks 37 and 38 respectively by the bars AC and BD. It will be understood that the line of centers of such parallel equal crank four-bar linkage is designated by CD. Such line of centers, of course, is fixed and corresponds to the distance between the axes of rotation of the cranks 37 and 38.

Each of the cranks 37 and 38 is counterweighted, as shown respectively by the counterweights 39 and 40 (Fig. l).

Analogous cranks 41 and 42 are employed for mounting the lower sc'ore bar 34, such cranks also being equal in length and parallel to one another. Such cranks 41 and 42 also are analogously counterweighted.

The two four-bar linkages above described are respectively designated by the numerals 43 for the upper linkage and 44 for the lower linkage.

The linkages 43, 44 are geared to move together by any suitable means. For example, one or both of the shafts 37a, 38a (Fig. 3) can be geared by suitable cir: cular, toothed gears to rotate with shafts 41a and 42a respectively mounting the cranks 41 and 42 ('Fig. 3).

Referring again to Fig. la, it is seen that the score bar 34 comprises the connecting rod BF of the lower fourba'r linkage, theline of centers thereof being indicated by GH and the respective cranks 41 and 42 by EG and FH.

The power means for driving the conveyor 10 is shown in Fig. 1 comprising an electric motor 45 which is drivably connected, for example, to the sprocket wheels 15 and 17 by' any suitable means, thereby to drive same at a selected angular speed.

I have found it desirable to drive the linkages 43 and 44 also by the electric motor 45, thereby facilitating the maintenance of a selected phase relationship between the motion of the' linkages and the motion of the conveyor 10.

The score bars 33 and 34 are brought together in scoring cooperation, as is well shown in Fig. 2, wherein the leading edge of. the bag 11 is substantially in alignment with the leading edges of the score bars 33 and 34. By so adjusting the motion of the linkages 43 and 44 to bringv such leading edges into register, as shown in Fig. 2, it is possible for the novel scoring device to score all widths of bag tubes without special adjustment there'- for and up to the limit of the length of such score bars.

In order to insure a proper phase relationship between the movement of the score bars 33 and 3-4 and the movement of the conveyor 10 and hence the bag tubes, it is, of course necessary to have one complete cycle of movement of the score bars for every complete cycle of movement of a bag tube with respect to a norm or reference point at the scoring station. That is, there should be one score bar cycle for each bag tube cycle. maintenance of such reiationship of cycles, that is,in the maintenanceof the same frequency of linkage (-or score bar) cycles and bag movement cycles, the factors to be considered'are:

(a) The radius of the'cranks of the linkages43 and 44 representative of which is the radius of the crank 42 (Fig. 3), which radius is measuredbetween the shaft center 42b and the supporting stud center 42c;

(12') The perpendicular distance between the axis of rotation of the shaft 42a and the plane of the bag tube In the 11, such plane, in the form shown, being coincident with the plane of the scoring region. Such distance is indicated by the dimension 46 (Fig. 3) which is greater than the aforementioned crank radius designated at 47;

(c) The common interval between the bag tube clamps;

(d) The necessity to have the linear speed of the score bars (in the direction of motion of the bag tubes) synchronous with the linear speed of the conveyor at the time of scoring.

If the cranks of the linkages are driven continuously at a constant angular speed sufiicient to provide a linear speed of the score bars which is equal to the linear speed of the conveyor, the aforementioned 1:1 ratio of the frequencies of the score bar cycle and bag cycle could not be maintained in view of the constant interval y. This is true because of the difierence in the length of the radius 47 and the dimension 46 (Fig. 3). Consequently it is necessary to speed up the angular motion of the score bars, as they approach the scoring region, to the point where they are synchronous in speed with the forward motion of the bag tubes, and thereafter slow them down until the proper time again arrives for increasing the speed. Thus a cyclical variation in angular speed of the cranks of the linkages 43 and 44 becomes necessary.

I have found it advantageous to select the radius 47 to be less than the dimension 46 in order to avoid interference with the score blade 35 and with the groove 36 by studs 33a and 340 (Fig. 5) which interconnect pivotally each of the aforementioned cranks with their respective score bars. That is, I have found that the radius 47 cannot be equal to the dimension 46 without damage to the bag tube or detriment to the apparatus itself.

Consequently the angular speed of the cranks of each of the linkages 43, 44 is under the influence of a pair of elliptical gears 48 and 49 (Figs. 1, 2 and 6), which gears are interposed in the operative interconnection between the motor 45 and the driving shafts of the aforementioned cranks. The elliptical gears are so adjusted that the maximum linear speed of the score bars 33 and 34 is attained at the time of maximum penetration of the score blade 35 into the groove 36. The relative attitu-des of the gears 48 and 49 at this point is illustrated in Fig. 2, it being understood that the contours of such gears are shown in somewhat exaggerated form for illustrative purposes in such Fig. 2 and also in Fig. 1.

Any other suitable means can be employed for so cyclically varying the angular speed of the cranks of the linkages 43 and 44. For example, a crank and slotted disc linkage can be employed.

Referring to the gear train illustrated in Fig. 6, which includes the aforementioned elliptical gears, the elliptical gear 43 is mounted for rotation upon a shaft 50 having coaxially mounted thereupon a gear 51 which is operatively associated with a further drive shaft via a smaller gear 52 which is driven from the main driving power line of the motor 45. The elliptical gear 48, of course, is in mesh with the elliptical gear 49, the latter being secured to a shaft 53 for rotation therewith, the latter shaft being mounted in suitable bearings and having secured thereto a circular gear 54 which in turn is drivably connected to one of the drive shafts for a crank of the upper four-bar linkage. Also secured to the shaft 53 is a bevel gear 55 which may constitute part of an operative interconnection to the four-bar linkages (not shown) for scoring the opposite end of the bag tube. The axes of rotation of the two elliptical gears 48, 49 are slightly oif center, but are on their respective major axes, as is shown in Fig. 6. The maximum speed of the driven gear is attained when its smallest radius is aligned with the largest radius of the driving gear.

I have found it advantageous to select the dimension 46 ('Fig. 3) to be equal to the radius of the pitch circle of the sprocket wheels -18 (Fig. 1), such pitch circle radius being illustrated, for example, at 17a with respect to the wheel 17.

However, there is a slight discrepancy between the radius of such pitch circle of the sprocket wheels 15--18 and the radius of the outer circle of such sprocket wheels. The plane of motion of the bag tubes is removed from the center of such sprocket wheels by a distance equal to the radius of such outer circle. Consequently, the plane of the axes of rotation of the shafts 41a and 42a may be slightly raised above the plane of the axes of rotation of the sprocket wheels 1518 in order to compensate for the difference between such pitch circle radius and outer circle radius.

In operation, the motor 45 is energized thereby to drive the conveyor 10 and the scoring mechanism 32. The bag tube blanks which are to be scored are successively grasped by the cooperating pairs of bag clamps, as at 19 and 20, and are pulled in succession past the scoring station wherein there occurs one cycle of bag movement for every cycle of score bar movement. The elliptical gears 48 and 49 are effective progressively and cyclically to increase the angular speed of the cranks of the linkages 43 and 44 thereby progressively to increase the linear speed of the score bars 33 and 34 whereby such speeds become synchronous with that of the conveyor 10, and hence the bags moved thereby, at the scoring region. Such synchronous speed relationship is achieved preferably at the point of maximum penetration of the score blade with the score groove 36. Thereafter the score bars continue their reciprocative connecting rod type of motion progressively to the relatively slowest angular speed at a point 180 removed from the scoring position whereupon such angular speed of the cranks gradually increases again to a maximum in the scoring region, and in particular at the point of maximum penetration of the score blade in such groove.

There is thus provided a novel scoring device which fully overcomes prior difiiculties with respect to the formation of curved score lines which are particularly disadvantageous when such lines are to comprise the base fold line of bag tubes.

the bag score lines are always perfectly straight or perfectly in accordance with the shape of the scoring elements. Furthermore, the novel scoring apparatus is of a versatility heretofore not found with the same degree of reliability and accuracy in that the novel apparatus can score all types of bags with straight score lines and also can score all widths of bags without need for any adjustment for any change in width, it being understood, of course, that all widths of bags up to the length of the score bars can be accommodated. That is, the apparatus embodying the present invention will score any width of bag having a given basis weight of paper and a given number of plies without any adjustment between such widths and up to the length of the score bars. If the base weight of the paper of the bag tube is changed or the number of plies thereof is altered, a suitable adjustment of the device can easily be made whereby the degree of penetration of the scoring means is adjusted for the new conditions. Such adjustment need be made only once with respect to the new base weight of paper or new number of plies and thereafter no further adjustment need be made for that type of bag tube.

The aforementioned adjustment of the apparatus for adjusting such degree of penetration of the score blade, can be effected by adjusting the position of the score blade 35 (Fig. 5) in the score bar 33. Referring to Fig. 3, it will be seen that four horizontal adjustment bolts 35a are mounted in and uniformly spaced along the score bar 33 for the purpose of controlling the clamping action of the score bar upon the blade 35. Also in such Fig. 3, vertical adjustment screws 35b are mounted in and uniformly spaced along such score The novel scoring device is reliable to a degree heretofore unattained in that 7 ban the lower extremities of which, as is wen shown in Fig. 5, bear upon the upper surface of the score bl'ade By adjustment of such bolts 35a and'scr ews 35b the degree of protuberance of the blade 35 can be adjusted with respect to the score bar 33, and hence thede'gree of penetration of such blade into the tube 11 can be adjusted.

While the invention has been described with respect to a preferred example which has given satisfactory -results, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended therefore in the appended claims to cover all such changes and modifications.

What is claimed is:

1. In apparatus of the class described, conveyor means for conveying a succession of bag tubes spaced at a common interval along a common path and at a selected frequency with respect to a scoring station; means for scoring each of such bag tubes in succession as each passes such scoring station along such common path and comprising a pair of score bars between which each tube is pressed in succession, such score bars extending in the direction of movement of, such bag tubes and being adapted for scoring the bags in such direction of movement, one of such score bars including a score blade positioned for entering a score groove formed in the other of such bars, said score bars comprising parallel portions of a pair of parallel equal crank four-bar linkages, the latter linkages being positioned and operatively associated for urging said score blade into such groove at the aforementioned station; the common radius of the cranks of such linkages being less than the dimension from the axis of rotation of such cranks perpendicular to the plane of the scoring region; means for rotating in timed relationship said cranks of said parallel equal crank four-bar linkages and including means for cyclically varying the angular speed thereof as a function of the differential between such radius and such dimension, whereby the linear velocity of said score bars is brought into synchronism 8 with the linear velocity of said conveyor means during scoring cooperation of said score bars; means tar operatively interconnecting said conveyor means 'sfia parallel equal crank fourba'r linkages, thereby to bring the cycle of bag movement by said conveyor means into phase with the cycle of score ba'r movement, whereby said bag tubes are scored in succession at such scoring station. f

2. In apparatus of the class described, bag tube conveyor means for conveying a succession of bag tubes at a common interval and along a common pathjand including means for grasping tsuch bag tubes at the leading edge thereof and pulling same along such common path; a pair of parallel equal crank four-bar linkages located at a bag tube scoring station and each having a connecting rod comprising a score bar, such linkages having a crank radius which is less than the perpendicular distance from the of any such crank to the bag tube scoring line, said linkages being positioned along said path on opposite sides of the zone of movement of said bag tubes therealong, said linkages being interconnected for periodically bringing said connecting rods into close relation for pressing therebetween along such scoring line a bag tube which is being moved along said path by said conveyor means; and means 'for cyclically varying the angular speed of the cranks of said linkages as a function of the diiference between such radius and such perpendicular distance; and means for 'operatively interconnecting said conveyor means and linkages to bring the cycle of bag tube movement by said conveyor means into phase with the cycle of score bar movement whereby said bag tubes are scored in succession at said scoring station, and whereby the linear speeds of said rods and conveyor means are brought into synchronism at such pressing line.

References Cited in the file of this patent UNITED STATES PATENTS Burroughs Oct. 2, 1951'

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