US 3236027 A
Description (OCR text may contain errors)
1966 A. SCHMERMUND PACKAGING MACHINES 10 Sheets-Sheet 1 Filed May 8, 1961 1966' A. SCH-MERMUND PACKAGING MACHINES l0 Sheets-Sheet 2 Filed May 8, 1961 Feb. 22, 1966 A. SCHMERMUND 3,236,027
PACKAGING MACHINES Filed May 8, 1961 10 Sheets-Sheet 5 F/GJ Feb 1966 A. SCHMERMUND 3,
PACKAGING MACHINES Filed May 8, 1961 lO Sheets-Sheet 4 1966 A. SCHMERMUND PACKAGING MACHINES 1O Sheets-Sheet 5 Filed May 8, 1961 Feb. 22, 1966 A. SCHMERMUND 3,236,027
PACKAGING MACHINES Filed May 8, 1961 lo sheets-sheet 6 PACKAGING MACHINES l0 Sheets-Sheet 7 Filed May 8, 1961 F/GS.
Feb. 22, 1966 SCHMERMUND 3,236,027
PACKAGING MACHINES Filed May 8, 1961 10 Sheets-Sheet 8 W 1% i i u u 22 1966 A. SCHMERMUND 3,236,027
PACKAGING MACHINES Filed May 8, 1961 10 Sheets-Sheet 9 F/G/Z V W A? 2/3 206 2// 20/ 2/6 20/206 2// 2/4 1966 A. SCHMERMUND PACKAGING MACHINES Filed May 8, 1961 10 Sheets-Sheet l0 United States Patent 3,236,027 PACKAGING MACHINES Alfred Schmermund, 62 Kornerstrasse, Gevelsherg, Westphalia, Germany Filed May 8, 1961, Ser. No. 108,423 1 Claim. (Cl. 53-4188) The invention relates to packaging machines, wherein articles are enveloped in wrapping material and overlapping portions of the wrapping material are glued together. On high-speed packaging machines the portions glued together are usually heated to accelerate drying of the glue.
For this purpose walls of guide channels, of guide chutes or similar guide passages for the wrapped articles are provided with electric heating bodies positioned against wall surfaces outside the channels, chutes or the like, so that such walls are heated throughout.
Such arrangements are expensive in use, liable to disturbances and have also disadvantages caused by the construction of the heating bodies. A heating body usually comprises electric resistance wires Wound on mica plates, resistance wires of adjacent mica plates being insulated from each other by additional mica plates, the assembly of mica plates and wires being encased in a metal box internally covered with asbestos or ceramic insulating material. The insulation acts as an electric insulation and as a thermal insulation, so that in use a high temperature exists within the heating body; moreover heat created within the body cannot easily reach the outside thereof. Thus, a high temperature has to be maintained within a heating body to enable the heating body to transmit a suflicient amount of heat to the walls to be heated. Consequently, the resistance wires are liable to fuse and have often to be replaced, which necessitates maintaining a stock of heating wires, so as to be able speedily to replace a wire which has become faulty.
Furthermore, the heating body has a high thermal inertia. Initially, a considerable time is required for heating before sufiicient heat is given off by the heating body. The heating body reacts only slowly, and with a considerable delay, to variations of an electric heating current, which are due to an automatic heat control arrangement. If for any reason the packaging machine stops it is necessary to separate the heated walls of the channels, chutes or the like from the packaging material since otherwise the packaging material may become scorched or burnt. The separation has to be effected automatically and means therefore are expensive It is an object of the present invention to provide a packaging machine wherein thermal inertia effects due to the presence of insulating material are virtually eliminated. The heating members are of simple and inexpensive construction and a minimum of heat is taken up in the interior volume of walls and the like of the machine.
It is a further object of the invention to provide such a machine in which heat is applied substantially solely to surfaces effective for bonding the packaging material, tear strips or the like.
Yet another object of the invention is to provide a machine in which heating surfaces are heated electrically at safe, low voltages, whereby the provision of insulating material may be reduced to a minimum.
It is a further object to provide a packaging machine wherein the temperature of heating surfaces may be maintained at a value such that packaging material is unharmed by remaining in contact therewith should the machine be stopped for any reason, while the electric power consumption is also and consequently kept low.
A feature of the invention consists in a packaging machine comprising a guide passage having a wall or wall portion of electrically conducting material, means being provided for feeding an electric current to said wall or wall portion for heating the same, further means being provided for ensuring mechanical contact between said wall or wall portion and wrapping material to heat the same.
According to another feature of the invention the electrically conducting material may be in the shape of a tape. Means may be provided for tensioning the tape. The tensioning means may comprise a tensioning screw co-operating with a holder for the tape and arranged for displacing said holder when said screw is turned.
Alternatively, the electrically conducting material may be in the shape of a profiled metal bar.
According to further features of the invention a thermostatic device may be provided and arranged for sensing the temperature of the electrically conducting material and for automatically controlling the electric current in dependance on the sensed temperature. Means may be provided for temporarily increasing the electric current on starting the machine so as to reduce the time required for heating the electrically conducting material to a desired temperature. The increasing means may comprise a time-delay switch.
Since the electrically conducting material makes mechanical contact with enveloping wrapping material to be heated, an electric current of high sensitivity but low voltage may be fed to the conducting material. The voltage may be so low that it is electrically safe to touch the conducting material while the current is flowing therein. Since the conducting material is in mechanical contact with the wrapping material, the temperature of the conducting material may in most cases be kept below 200 C. and may in exceptional cases reach 200 C., or, at the most 250 C. At such temperature the conducting material if made of a suitable metal or metal alloy does not oxidise or fuse. Owing to the low voltage the electric insulation of the conducting material may be kept to a minimum. In order to save electric energy, the conducting material may be heat insulated at its parts remote from the wall or wall portion to be heated. It has been found that in some cases 50 watt may be sufficient. The heat transmitted from the electrically conducting material to the enveloping wrapping material may not only be used for drying a glue or other adhesive, but may alternatively be used for heat sealing the wrapping material if a suitable wrapping material is used.
To make the invention clearly understood reference will now be made to the accompanying drawings, which are given by way of example and in which:
FIG. 1 illustrates a side view of an arrangement for heating heat-scalable wrapping material whereby to attach a tear-strip thereto;
FIG. 2 illustrates a front FIG. 1;
FIG. 3 illustrates a section along the line IIIIII of FIG. 5 of a part of a packaging machine comprising means for heating a guide channel for wrapped articles;
FIG. 4 illustrates a side view corresponding to FIG. 3;
FIG. 5 illustrates a section along the line VV of FIG. 3;
FIG. 6 is an electric circuit diagram of the arrangement of FIGS. 3, 4 and 5;
FIG. 7 illustrates a modified arrangement;
FIG. 8 illustrates another modified arrangement;
FIG. 9 illustrates a further modified arrangement;
FIG. 10 illustrates a section along the line X-X of FIG. 11 of a further modification;
FIG. 11 illustrates a section along the line XIXI of FIG. 10;
FIG. 12 illustrates a section along the line XII-XII of FIG. 11;
view of the arrangement of FIG. 13 illustrates a section along the line XIII-XIII of FIG. 14 of a still further embodiment;
FIG. 14 illustrates a section along the line XIVXIV of FIG. 13;
FIG. 15 illustrates a section along the line XVXV of FIG. 14; and
FIG. 16 illustrates a circuit diagram.
By means of the arrangement of FIGS. 1 and 2, a narrow tear strip 14 is fixed to a wider web 13 made of cellulosic or other heat-scalable material.
The arrangement comprises a heating bar 2 of a thickness s and a width b. The bar 2 is attached to, but insulated from, a U-shaped holder 1 which in turn is fixed to a transverse rod 10 mounted on a support 9. Heating current is fed to the bar 2 by means of conductors 3 and 4, which preferably are made of flexible copper beads, the conductors 3 and 4 being insulated by insulators 5, and electrically connected to the bar 2 by clamps 6. In front of the bar 2 a brush 7 is provided which is fixed to the rod 10.
The end of each tear strip 14 is cut into shape by a cutting device 15, 16, 17 known per se. Feed rollers 18 feed the web 13 and the tear strip 14 from bobbins (not shown) across guide rollers 11 and 12 through the arrangement.
The heating bar 2 is preferably made of a chromium alloy and is electrically heated from a mains by means of a transformer. A thermostatic device (not shown) maintains the temperature of the bar 2 at a required value.
The bar 2 is heated to the required temperature only along its part of thickness s and width b where the crosssection a x b is small, whereas its temperature is not essentially increased beyond room temperature along its parts of larger cross-section where in addition any heat is quickly conducted away.
When the machine stops and the feed of the web 13 and tear strip 14 is interrupted, a simple relay (not shown) interrupts or reduces the heating current circuit so that the web 13 and tear strip 14 are not overheated while arrested. When the machine is re-started, the heating current circuit is closed again so that the required temperature of the bar 2 is restored. If desired, an additional time-relay may be provided for temporarily increasing the heating current and thereby reducing the time required for the bar 2 to reach its required temperature.
In FIGS. 3 to 6 a heating arrangement is illustrated, which may be used in packaging machines and which comprises a guide channel at the end of a feed table 116 for wrapped articles, Walls of the guide channel being heated at regions where glued seams are present in a wrapping enveloping an article. The walls of the guide channels are usually so arranged that wrapped articles can travel through the channel with lateral play so as not to impede movement of the articles by unavoidable slight differences in their dimensions. On the other hand, if packed articles are moved through a'vertical channel the articles are held therein by brushes or other resilient means so as to prevent the articles from dropping down when not supported.
FIGS. 3 to illustrate a vertical guide channel formed between a channel wall 124 and three further channel walls 106. A push member 119 is provided, which is vertically reciprocatable, for pushing a wrapped article 117, for example a box of cigarettes, which arrives at the end of the horizontal feed table 116, upwards into the guide channel. A second push member 125, which is horizontally reciprocatable, is provided for laterally moving an assembly 118 of a plurality of wrapped articles out of the guide channel onto a horizontal guide plate. The channle walls 106 are movably held by the levers 111 forming parallelogram-guides and which are mounted by means of spindles 113 on a frame 115. The levers 111 carry the channel walls 106 by means of spindles 112 and rods 122. The channel walls 106 serve to heat the articles 11 and each wall 106 c mp i e a te ionabl me al ic heating tape 101, which is fixed to holders 106' and 108 by means of cylindrically thickened end portions 102 and 107, the portion 102 and the adjacent tape being provided with insulating layers 105. If desired, the thickened portion 107 could be similarly insulated. Each holder 108 is provided with a bar 122 journalled to two parallel levers 111. Each holder 106 is displaceably mounted in the respective holder 108, and the heating tape 101 can be tensioned by screw means comprising a nut 123 on a screw-threaded spindle carrying a holder 106' and engaging a bore in the holder 108 against a shoulder of which the nut 123 bears. A lead 104 connects each thickened portion 107 to a terminal 135 connected to earth 134 (see FIG. 6). A lead 103 connects each thickened portion 102 to a secondary winding 133 of a transformer, the primary winding 130 of which is connected at 131 to a mains supply. The transformer is a low voltage transformer supplying at its secondary winding 133 a heavy current at a low voltage.
The arrangement operates in the following manner:
The vertically reciprocatable push member 119 pushes individual articles 117, for example cigarette boxes, which arrive from the feed table 116 upwards into the vertical guide channel between the walls 124 and 106. An assembly 118 of articles at the upper end of the guide channel is pushed by the second push member on to a horizontal guide plate. On each upwards movement of an article 117 by the push member 119 the three movable channel walls 106 are forced to move somewhat outwards so that the articles can move upwards without substantial friction, the walls 106 being held in their initial positions by spring means (not shown). Electric current flows through the tapes 101 forming portions of the walls 106 and heats said tapes, the heat being directly transmitted from the tapes to the articles sliding therealong, so that any glue of the wrapping material is dried during the passage of the articles through the guide channel.
Many modifications are possible.
For example, as illustrated in FIG. 7, the heating walls of the guide chute each may comprise a heating tape 301 which at its end is fixed to ends, remote from each other, of two bars 302 and 303 which are insulated from each other by a layer 304 of insulating material and insulating washers 306, and are connected together by screws 305 and nuts 307. The screws 305 pass through elongated holes in the bar 302 so that after loosening the screw connection the bars 302 and 303 are displaceable relatively to each other for tensioning the heating tape 301. The bars 302 and 303 are carried by bearings 310 on parallel levers 314 and are insulated therefrom by insulating material 309, 312 and 311. The levers 314 are pivotally mounted on pivot shafts 315 of holders 316 of a frame 322. The levers 314 are movable by means known per se.
Whereas the heating walls each formed by the heating tape 301 are movable, a well 324 of the guide chute is fixed in position and is not heatable. The wall 324 is fixed to a bar 325 which in turn is fixed on bars of the frame 322, the bar being analogous to the bars 340 of the embodiment of FIG. 9. Electric heating current is fed to the bars 302 and 303 and thence to the tape 301 by means of conductors 317.
A push member 327 is vertically reciprocatable for pushing articles 330 arriving at the end of a feed table 326 through the chute. A second push member 323, which is horizontally reciprocatable, removes an assembly 329' from the chute as its upper end.
With the embodiment of FIG. 7, the movable heating walls of the chute may be arranged for exerting a substantial pressure on articles 330 travelling through the chute so that not only glue of the wrapping is dried under heat, but the articles, for example cigarette boxes, are pressed into rectangular shape.
In the arrangement of FIG. 8, which is generally similar to that of FIG. 7, a heating wall 3311s rigid; and, as
is visible in FIG. 9, has U-shaped recesses for reducing the cross section. The wall 331 is preferably made of an electrically conducting metal alloy to form an electric heating resistance, the wall 331 being mechanically sufficiently resistant and is corrosion resistant. The heating walls 331 are insulated by insulating material 333, 337 and attached to arms 334 mounted on pivot shafts 313 of of levers 314. The shafts 313 are fixed to holders 318 of a frame 338. Current is fed by conductors 332.
In the embodiment of FIG. 9 a chute is provided having a rigid, not heatable wall 324 analogous to the wall 324 of FIG. 7 or 8, a heatable wall 301 analogous to the wall 301 of FIG. 7 and two heatable walls 331 analogous to the wall 331 of FIG. 8. Since FIG. 9 illustrates a section perpendicular to the sections of FIGS. 7 and 8 further details of the walls 301 of FIG. 7 and 331 of FIG. 8 are recognizable from FIG. 9.
The embodiments of FIGS. 10 to comprise heating arrangements suitable for heating glued, welded or otherwise sealed lateral portions of a wrapped article.
The arrangement of FIGS. 10 to 12 comprises thin tensionable heating tapes. A guide passage for articles 218 is formed by heating tapes 201 and a feed table having two portions 213 and 214 to which, by means of screws 209, holders 205 for the heating tapes 201 are fixed, onto to each of said portions. Each holder 205 carries one lheating tape 201, which has thickened ends 202 each mounted in a slotted tube 204 of insulating material. Each heating tape 201 is made of electrically conducting, sufficiently heat resisting material. At its side remote from articles to be heated, the tape 201 carries a layer 220 of insulating material. Each holder 205 has a slot 206 enabling tensioning its tape 201 by means of a screw 208. Electric current is fed to the tape 201 by means of conductors 203. Lateral guide rails 212 are provided for guiding the articles 218 to the heating tapes. Push members 216 move articles 218 through the heating arrangement. A lid 217 covers the top of articles 218.
The arrangement of FIGS. 13, 14 and 15 comprises heating bars 222 of a cross section visible in FIG. 15. A guide passage comprises a feed table having two portions 229 and 230 along which articles 218 are moved by a push member 216. One heating bar 222 is provided at each side of the articles to form, together with the feed table a guide passage. Each heating bar 222 is insulated by insulating material 226 and 227 from, and is attached to, holding bars 223 by means of screws 224, the holding bars 223 being fixed by screws 210 engaging elongated holes 209 of the bars 223 to the feed table portions 229 and 230. Electric current is fed through conductors 228. Lateral guide rails 212 are provided for guiding the articles 218 to the heating bars.
In operation of the embodiments of FIGS. 10 to 15, a heavy current of low voltage is fed to the heating tapes or heating bars which are quickly heated to a desired temperature and transmit heat by direct contact quickly and effectively to the articles to be heated.
By providing heat sensitive devices at suitable places of the heating tapes or bars, for example at their sides remote from the articles to be heated, the heat can be controlled by suitable control means acting, for example, on the current flowing through the primary winding of a transformer linking the tapes or bars to an electric mains.
A circuit diagram comprising a heat sensitive device is shown in FIG. 16, in which the reference numerals 101, 130, 133, 134 and 135 indicate the same parts as the corresponding reference numerals of FIG. 6. An electromagnetically operable switch 140 lies in a mains supply circuit for an electric current having three phases U, V, W for energizing the primary windings 130 of a three phase transformer, the secondary windings 133 being connected to three wall portions 101 to be heated. An earthed wire is indicated by 0. A heat sensitive resistor 136 is placed against one of the walls 101 so as to be heated by said wall, the resistor 136 being held in position by a heat insulating holder 137. The heat sensitive resistor 136 lies in series with a variable resistor 149 and both resistors 136 and 149 he in the control circuit of a cold cathode tube 139. A voltmeter 138 lies across the resistor 136. A biasing potential is applied to the control circuit of the tube 139 through a resistor 145. An electromagnet 148, the-contacts of which are normally open, lies in the anode circuit of the tube 139, and is arranged for operating the switch 140. An anode resistor 146 and a rectifier 147 also lie in the anode circuit of the tube 139. The tube 139 is ignited at a predetermined voltage on the control electrode of the said tube. As long as the voltage on the control grid is below the predetermined voltage the tube 139 is not ignited; it is ignited when the voltage on the control grid is equal or higher than the predetermined voltage, which for example may be volts. When the tube 139 ignites, the electromagnet 148 is energized and closes its contacts, whereby the switch 140 is operated and energizes the transformer windings causing the wall portions 101 to be heated by the transformer windings 133. The resistor 136 is heated and its resistance reduced, so that the voltage on the control electrode of the tube 139 is decreased and the tube 139 quenched. The electromagnet 148 relapses and causes the switch to open. The walls 101 cool down, causing the resistor 136 to cool down. Thereby its resistance increases until the tube 139 is re-ignited and so on. Thus, the temperature of the walls 101 oscillates between two limits which may be narrow. The mean temperature about which the temperature of the walls 101 oscillates is settable by means of the variable resistor 149 since the heat sensitive resistor 136 and the resistor 149 together constitute a potential divider. The variable resistor 149 may be calibrated in temperature values, corresponding to mean temperatures about which the wall temperature oscillates. The voltmeter measures the voltage drop across the heat sensitive resistor 136 which is proportional to the instantaneous wall temperature. Again, the voltmeter 138 may be calibrated in temperature voltages.
In a packaging machine, a plurality of substantially vertically extending walls disposed adjacent each other to form a guide channel chute therebetween, a plunger adapted to move Wrapped packages upwardly in said channel and between said walls along said channel chute, a first heated rigid wall having a substantially planar flat surface facing toward said guide channel chute, a second wall having a cross section consisting of a plurality of U shape recesses with said recesses to form a substantially flat planar surface facing toward said chute, said second wall being made of electric resistant material, and means to feed electric current directly to said second wall, two other walls with substantially flat planar surfaces facing toward said chute, and means for moving at least two of said walls toward an oppositely disposed wall, whereby said packages can be heat sealed as they are moved through said chute.
References Cited by the Examiner UNITED STATES PATENTS 1,061,039 5/1913 Borchert 53-388 1,924,045 8/1933 Molins et al. 53-388 2,113,269 4/1938 Engel 53-379 X 2,609,316 9/ 1952 Fichtner.
2,638,724 5/1953 Harvey 53-379 X 2,855,977 10/1958 Wagner 53-379 X 3,020,691 2/1962 Oxborrow 53-375 X TRAVIS S. MCGEHEE, Primary Examiner.
ROBERT A. LEIGHEY, FRANK E. BAILEY,