US3280704A

US3280704A - Method and apparatus for folding endless flat tubes

Info

Publication number: US3280704A
Application number: US518514A
Authority: US
Inventors: Ahlbrandt Andreas
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-12-13
Filing date: 1965-12-13
Publication date: 1966-10-25
Anticipated expiration: 1983-10-25

Description

Oct. 25, 1966 AHLBRANDT 3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Original Filed May 6, 1963 4 Sheets$heet l Oct. 25, 1966 A. AHLBRANDT METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES 4 Sheets-Sheet 2 Original Filed May 6, 1963 I11 verzzor A. A Z Z @2772; fi e'/bz ji Oct. 25, 1966 A. AHLBRANDT 3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES 4 Sheets-Sheet 5 Original Filed May 6, 1963 r 6 B M ,b m Fm I Q .9 v y w F H WU.# Z A. A

Oct. 25, 1966 A. AHLBRANDT 3,280,704

METHOD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Original Filed May 6, 1963 4 Sheets-Sheet 4 Fig. 77 //3 I75 five-175w A. A1 ZZH-z-ncZZ United States Patent Ofiice 3,280,704 Patented Oct. 25, 1966 3,280,704 METHQD AND APPARATUS FOR FOLDING ENDLESS FLAT TUBES Andreas Ahlbrandt, Uhlandstrasse 17, Lauterbach (Hessia), Germany Continuation of application Ser. No. 278,092, May 6, 1963. This application Dec. 13, 1965, Ser. No. 513,514 18 Claims. (Cl. 93-20) The present application is a continuation of application Serial No. 278,092, filed May 6, 1963, now abandoned and is a copending application to an application Serial No. 234,285, filed December 10, 1962, now Patent No. 3,185,044. The present invention relates to a device for folding endless flat tubes. In the above-mentioned copending application there is described a method of folding the lateral marginal portions of endless fiat tubes intended for use in the manufacture of bags or sacks which, in a filled condition, will approximately assume the shape of a parallelepiped. According to the copending application, the tube, during its continuous longitudinal motion, is turned about its longitudinal axis by one half of the width of one of its lateral surfaces; in other words, any point lying on the flat tubular web is offset in a lateral direction by one-half of the width of one lateral surface thereof in a direction perpendicular to the longitudinal line. This method affords a solution to the problem of providing the bags or sacks with a continuous print impression which will not be interrupted by a lateral-edge folding line, since the portions intended to form the lateral surfaces, before being turned, lie completely in the upper and lower parts respectively of the web. In the conventional practice, the areas intended to form the lateral surfaces lie partly (one-half) in the upper portion of the tubular web, and partly (one-half) in the lower portion of the tubular web while the printed impression is being applied.

An object of the present invention is to provide a method for manufacturing bags or sacks having no lateral folds, especially the well-known cross bottom or satchel bags, by turning an endless fiat tube having printing impressions on its lateral marginal surfaces by one-half of the width of said lateral surfaces, in order to achieve bags or sacks having a continuous printed impression which will not be interrupted by a lateral folding line.

The present invention further relates to a device adapted to carry into effect the method of the invention in the manufacture of bags or sacks having no lateral folds.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating several preferred embodiments of the invention wherein:

FIG. 1 is a plan view of a folding device according to the invention;

FIG. 2 is a longitudinal cross-sectional view of the folding device of FIG. 1 taken along line II-II;

FIG. 3 is a longitudinal cross-sectional view resembling FIG. 2 but showing a modified embodiment of the invention;

FIGS. 4 to 8, respectively, show cross-sectional views taken along the lines IV-IV to VIIIVIII in FIG. 1;

FIG. 9 is a plan view of another embodiment of a device for carrying into practice the method of the invention;

FIG. 10 is a side elevational view of the embodiment of FIG. 9;

FIG. 11 is a cross-sectional view of the embodiment of FIG. 9 taken along the line XI-XI;

FIGS. 12 to 16 diagrammatically illustrate the various steps performed by the device of FIGS. 9 to 11;

FIG. 17 is a side elevational view of still another embodiment of the invention; and

FIG. 18 is a plan view of the embodiment of FIG. 17.

Referring to the drawings, the folding device shown in FIGS. 1 and 2 comprises two identically constructed guide plates and 101 disposed and fastened to either side of a supporting member 108. The two guiding plates carry rotatable discs 102 on their diagonally opposed corners in order to reduce friction. As shown in FIG. 2, the guiding

plates

100 and 101, the supporting member 108, and the discs 102 are disposed within an endless flat tube which is to be turned and folded. Their weight is borne by rollers 106 which are rotatably mounted in the frame of the device. The rollers 106 cooperate with rollers 107 which are interconnected by axles and are carried for rotation on the supporting memer 108, i.e. the lower half of tube 130 runs between

rollers

106 and 107. The

rollers

106 and 107 are disposed with their axes extending at an angle to the longitudinal center line of the device and perpendicular to the guiding edges of the guiding plate 101. This arrangement is necessary because the lower wall of the tubular web which is guided by the guiding plate 101 is moving at an angle to its original direction of travel.

The frame of the device is formed by channel sections 131. Pairs of spindles 132 and rollers 133, between which the tube is pulled through, are mounted in the channel sections 131. Rollers 134, which are secured to the front and back ends of the supporting members 108, bear against the rollers 133. The rollers 134 receive the thrust exerted by the tube 130 on the

guide plates

100 and 101. At the off-running end of the device, spindles 135 are secured to the frame uprights 137. The spindles 135 carry a pair of rollers 136 which act to press together the folded tube 130. Longitudinal frame members 138, extending parallel to the central axis of the folding device, are secured to the channel sections 131. Displaceab-ly mounted thereon are

bearers

139 and 140 disposed in pairs and within the latter are movably mounted displaceable rods 14-1 on the ends of which are mounted either guide rollers 142 or folding discs 104. The rollers 142 are provided in greater numbers than shown in the drawings. Only a limited number have been shown for the sake of clarity.

As will be seen by FIGS. 1 and 2, the two guiding

plates

100 and 101,'which carry the rotatable discs 102 on diagonally opposed corners, are disposed in two parallel planes and cross in space. The amount of relative displacement of the plates is the same on the ion-coming side and on the off-running side of the guiding plate. The printed impressions 103, which are indicated in dotted lines in FIGS. 4 to 8, show the width of the lateral surfaces formed subsequently as parts of the bags or sacks .to be manufactured. It will be seen in FIGS. 1 and 5 that the distance between the guiding edges of the

plates

100 and 101 on both sides of the tube on the on-coming side of the device amounts to approximately one-half only of the width of the lateral surface. Since the guiding edges of the

plates

100 and 101 cross in space at the center of the device, the tubular web would no longer be held taut at this point unless it were folded inwardly, as shown in FIG. 6, by the rotatable disc 104 extending from the outside into the gap between the

plates

100 and 101. The discs 104 serve to produce inwardly extending folds 105 which are, however, exclusively intended to tension the tubular web, the folds being folded outwardly again at a later stage of manufacture As shown in FIG. 6 one-half of the printed impressions on the lateral surfaces are disposed on the upper side of the tubular web in the region of the discs 104, the other half being disposed on the underside of the web. The inner half of the lateral surface is folded into the space between the

plates

100 and 101 by the respective discs 104. As the motion of the tubular web continues, the right-hand portion thereof is again spread outwardly by the guiding edge of the plate 101, the left-hand portion of the web being similarly spread outwardly by the guiding edge of plate 100, it being understood that, due to the distance between the guiding plates transversely to the central plane of the tubular web, the guiding edge engaging the web towards the off-running end of the device will produce its spreading action at the center line of the printed impressions applied on the lateral surfaces. In this manner there is produced a flattened tube, shown in FIG. 8, in which the two halves of the printed impressions are respectively disposed on the upper and lower sides of the web.

It is possible to eliminate the discs 104 and thus to omit the step of temporarily producing the lateral folded-in portions by providing guiding plates having a longitudinal across section of the shape shown in FIG. 3. In this case, the guiding plates are divergent up to the crossing point and thereafter converge again, the distance between the plate on the off-running side being again the same as that on the on-coming side. The increased distance between the plates, intermediate their ends, insures that the tubular web will be held taut- Another embodiment of the invention is shown in FIGS. 9-11. The framework of this embodiment comprises longitudinal frame member 145 to which are fastened frame uprights 144. At the on-coming end of the device, the tube 130 is guided by a roller 143 which is rotatably mounted between a pair of the frame uprights 144. A pair of rollers 146 and 147 follow the roller 143 in the running direction of the tube 130. The roller 146 .is rotatably mounted on a spindle 1149 while the roller 147 is rotatably mounted in arms 148 which are secured to the spindle 149. The spindle 149 is secured between a pair of uprights 144 and at one endis provided with a screw 109 having a hand crank 110 and extending through one of the longitudinal frame members 145. The screwserves to vary the angle of inclination of the rollers 146 and 147 with respect to the central plane of the folding device. The oblique disposition of the rollers. 146 and 147 is apparent from FIG. 11 which also shows themobility of the spindle 149 relative to the frame of the device.

A supporting member 150 is located in the middle axis of the tube and carries at one end an arm 151 on which two discs 152 and 153 are rotatably mounted. The arm 151 can swivel relative to the supporting member 150 and is set at the same angle as the pair of rollers 146 and 147. The spacing between the outer discs edges approximately corresponds to the tube width, as shown in FIG. 13. Forks 154, each carrying a roller 155, are secured through the supporting member 150 approximately midway between the rollers 152 and 153 and rollers 111, shown at rig-ht angles to the supporting member. The rollers 111 are rotatably mounted on a spindle 163 Which is secured to a pair of uprights 144. The other end of the supporting member is provided with rollers 156 which bear on a pair of rollers 157 which is turn are rotatably mounted on a spindle 158 secured to a pair of uprights 144. The rollers 156 serve to receive the thrust exerted by the tube on the supporting members 150. The lower roller 155 bears on a roller 159 which is rotatably mounted on a spindle 160 secured in a pair of frame uprights 144 (FIG. 11). A spreading device 161, made of thin wire or guiding plates, is secured near the arm 151 on the supporting member 150. A similar spreading device 162 is secured between the rollers 155 and the rollers 111. The tubular web, after having been spread in the spreading devices 161 and 162',is reflattened by the rollers 111 and spread by means of the spreading discs 112. Thus, the tubular web will emerge from the device again in the form of a flattened tube, but it will have turned in a circumferential direction by one-half of the width of a lateral surface thereof. At the off-running end of the device, again a pair of rollers 164, rotatably mounted on spindle 165 4 secured to a pair of uprights 144, act to press together the folded tube 130.

The sequence of steps performed by the second embodiment of the invention will now be described with reference to FIGS. 12 to 16. The endless flat tube, shown in FIG. 12, is preferably made of a thermoplastic material and is intended, for example, for the manufacture of bags or sacks. It has two lateral edges a and d. The flat tube is provided with printed impressions which will subsequently app-ear on the lateral surfaces, which are indicated in FIG. 12 between the lines a and c and the lines d and 1, respectively. It will be seen in FIG. 12 that the printed impressions, which will appear on the lateral surfaces, may

be applied simultaneously with those which are to appear.

on the wider surfaces of the bags or sacks. In FIGS. 13 to 15, dotted lines indicate those portions of the tube material which are intended subsequently to form the lateral surfaces. FIG. 13 shows the middle plane of the tube turned through an angle of a. The position of the lines a-f relative to the axis of the tube has remained unchanged. The turning of the plane of the tube is caused by the oblique position of the two rollers 146 and 147 and the rollers 152 and 153.- The inclination of these rollers relative to the middle plane of the folding device is so adjusted that the tube-is turned through half the width of the lateral surface thereof. As is shown in FIG. 14 the tube is then drawn out of the oblique position into a plane forming an angle degrees or approximately 90 degrees,

with the middle plane of the folding device. This operation is carried out by means of the pair of rollers 155 which, simultaneously with the displacement of the plane of the tube, cause a turning of the tube about its middle axisthrough half the width'of a lateral surface to be formed thereof. Following this step, the tube is flattened again by the rollers 111 and spread by the spreading discs 112, as illustrated in FIG. 15. In this condition, there have been formed the new lateral edges b and e which are centered between lines a and c and the lines d and 1, respectively. FIG. 16 shows the tube which has been rotated by one-half the width of one lateral surface about its longitudinal axis.- Thetube leaving the device of FIGS. 9 to 11 is in this form.

FIGS. 17 and 18 show a modification of the embodiment of FIGS. 9 to 11 in which the function of the tiltable guide rolls on the entry end of the device has been replaced by providing for the axle 113 of the supply reel. 114

to be tilted as required. Two later-a1 spaced apart cheeks 115, connected by a rear wall 117 support the supply reel 114 and a guide roll 11-6. The upper edge of rear wall 117 is inclined upwardly from the upper edges of the

cheeks forming surfaces

118 and 119. The rear wall 117 is supported for rotation about a pin 120 mounted in a frame 121; A worm wheel 122 is fixedly secured to the rear wall 117 and is disposed on the axis of the pin 120.

A worm gear 123 cooperates with the worm wheel122'.

with the aid of a spindle 124 journaled in arms 125 of the bracket 121 to tilt the rear wall 120, the cheeks 115 and the

rolls

114 and 116. The til-ting is actuated by turning hand crank 126. The inclination of the

surfaces

118 and 119 of the upper edge of rear Wall 117 is necessary to permit the worm wheel 122 to be mounted at a suificiently high. level so that the upper edges of the cheeks 115, when being swung round, will not foul against the spindle 124.,

The spreading device shown in the left-hand portions: of FIGS. 17 and 18 corresponds to the previously described spreading device of FIGS. 9 and-ll. Therefore, the description of this device will not be repeated. However, there is indicated at 127 a triangular spreading plate whose function it is to initiate the spreading apart of the two walls of the tube preparatory to the final spreading.

action. This action is complemented by the action of the spreading discs mounted downstream of the plate 127.

What is claimed is: 1. A method of transforming a continuously moving flattened tube of artificial material which tube is characterized by two diametrically opposed fold lines and indicia along at least one marginal outer surface region lying adjacent to and on one side of one of the fold lines comprising the steps of spreading the tube to open same, keeping said tube taut, rotating said tube about its longitudinal axis a distance equivalent to one half the Width of the marginal outer surface region, and thereafter refiattening the open tube along new diametrically opposed fold lines parallel to but displaced from the original fold lines, one of said new fold lines lying midway of the marginal outer surface region so that the indicia now lie in marginal surface areas adjacent to but on opposite sides of said one new fold line.

2. A method according to claim 1 in which said tube is kept taut by temporarily forming inwardly directed accordian pleats in opposite sides of the tube adjacent to the new fold lines during its transformation.

3. A method according to claim 1 in which said tube is kept taut by vertically expanding a central portion of said tube during its transformation.

4. An apparatus for folding continuously moving fiat tube-like webs having two diametrically opposed fold lines and at least one longitudinally extending marginal portion bearing indicia along one of the fold lines and intended to be used to produce package bags comprising means for continuously moving the web longitudinally, means for spreading the web from within to open same, means for rotating th web about its longitudinal axis a distance which is equivalent to one half the width of the marginal portion of the Web to shift the indicia, means for keeping the periphery of said web taut during the rotation, and means for refolding the web along new diametrically opposed fold lines rotatably displaced from the original diametrically opposed fold lines with the indicia straddling one of the new fold lines.

5. An apparatus for transforming a flat running tubelike web having indicia on a marginal portion thereof comprising internal structural means including elongated first and second guide means oriented in the direction of longitudinal travel of the web, means supporting said guide means spaced apart in a direction perpendicular to the intended plane of travel of the web in spacial lateral displacement at both ends, said web being fed over said internal structure means and opened out thereby, means to support and retain the position of the internal structural means when a web is fed over same, means adapted to act on the lateral portions of said web as it passes over the internal structural means to initiate tautness in said web during the translation thereof, and means adapted to refiatten the web along new fold lines.

6. An apparatus for folding a flat running tube-like web according to claim 5 in which said means for inducing a tautness in the web comprises means adapted to act on the external lateral portions of said web as it passes over the internal structural means to initiate inwardly directed folds in the middle of one half of the marginal portion having indicia and the portion immediately diametrically opposed thereto, said inwardly directed folds being removed prior to the final folding of said web.

7. An apparatus for folding a flat running tube-like web according to claim 5 wherein the means to maintain tautness in said web comprises said guide means vertically diverging from the onrunning end and vertically converging towards the offrunning end, said guide means being at their maximum spacial relationship substantially at the median portion thereof.

8. A device for transforming an endless flattened tubular web of artificial material intended for the manu facture of bags, sacks and the like comprising spaced guiding means disposed within a moving tubular web, said guiding means spreading open said web, guiding edges of said guiding means engaging with the lateral edges of said web, said guiding means being disposed in opposing pairs on the outermost diagonal corners of a pair of spaced surfaces whose longitudinal medial axes intersect one another :at an acute angle, said surfaces being spaced perpendicular to the central plane of the tubular web, the distance between said guiding edges on the oncoming and olfrunning sides amounting to approximately one half the width of the lateral surfaces of the bags, sacks and the like to be produced.

9. A device for transforming an endless flattened tubular web according to claim 8 wherein said surfaces are parallel planar surfaces and in which means are provided to form at least one inwardly directed fold in said tubular web intermediate the ends of said parallel planar surfaces to insure a tautness of said web, said folds being removed prior to the final folding of said web.

It). A device according to claim 8 in which additional guiding means are disposed in the :region of the lines of intersection of the surfaces containing the guiding edges and extending parallel to the central plane of the tube, said additional guiding means extending from the outside centrally into the space between the first mentioned guiding means, the additional guiding means extending into said space a distance approximately equaling one half the amount through which it is desired to rotate the tubular web about its axis.

11. A device according to claim 9 in which said additional guiding means comprise a pair of rollers externally engaging the tube web and carried by displaceable rods and said guiding means comprise pairs of discs adapted to spread the tubular web from within.

12. A device for folding continuously moving flat tube-like webs having two diametrically opposed fold lines and at least one longitudinally extending marginal portion bearing indicia along one of the fold lines and intended to be used to produce package bags comprising means for continuously moving the web longitudinally, means for spreading the web from within, said spreading means comprising means for engaging the inner surface of said web along diametrically opposed lines lying in a plane oblique to the onrunnin'g plane of said web, said means for engaging the inner surface of said Web being disposed between two spaced guiding means, the planes of said guiding means subtending an angle corresponding to the amount through which the tubular web is to be rotated about its axis, and means for refolding the web along new diametrically opposed fold lines rotatably displaced from the original diametrically opposed fold lines with the indicia straddling one of the new fold lines.

13. A device according to claim 12 wherein the said means for engaging the inner surface of said webs consist of spreading discs.

14-. A device according to claim 12 in which the angle between said guiding means is adjustable.

15. A device according to claim 12 wherein a reel holding a supply of the tubular web material is rotatably mounted on an axis inclined from the horizontal so as to serve as a guiding structure at the oncoming end of the device.

16. The device according to claim 12 wherein a spreading plate is disposed within the tubular web upstream of said spreading discs.

17. A device according to claim 12 wherein the said spreading means further comprises guiding plates.

18. A device according to claim 12 wherein the said spreading means further comprise a guiding structure made of bent wire.

No references cited.

BERNARD STICKNEY, Primary Examiner.

Claims

5. AN APPARATUS FOR TRANSFORMING A FLAT RUNNING TUBELIKE WEB HAVING INDICIA ON A MARGINAL PORTION THEREOF COMPRISING INTERNAL STRUCTURAL MEANS INCLUDING ELONGATED FIRST AND SECOND GUIDE MEANS ORIENTED IN THE DIRECTION OF LONGITUDINAL TRAVEL OF THE WEB, MEANS SUPPORTING SAID GUIDE MEANS SPACED APART IN A DIRECTION PERPENDICULAR TO THE INTENDED PLANE TRAVEL OF THE WEB IN SPACIAL LATERAL DISPLACEMENT AT BOTH ENDS, SAID WEB BEING FED OVER SAID INTERNAL STRUCTURE MEANS AND OPENED OUT THEREBY, MEANS TO SUPPORT AND RETAIN THE POSITION OF THE INTERNAL STRUCTURAL MEANS WHEN A WEB IS FED OVER SAME, MEANS ADAPTED TO ACT ON THE LATERAL PORTIONS OF SAID WEB AS IT PASSES OVER THE INTERNAL STRUCTURAL MEANS TO INITIATE TAUTNESS IN SAID WEB DURING THE TRANSLATION THEREOF, AND MEANS ADAPTED TO REFLATTEN THE WEB ALONG NEW FOLD LINES.