US2321729A - Sealing of cartons - Google Patents

Description

June 15, 194 H. H. BEASLEY SEALING OF CARTONS Filed Jan. 27, 1941 4 Sheets-Sheet l SEALING 0F CARTONS 4 4 Sheets-Sheet 2 Filed 'Jan. 27, 1941 June 15, 1943. H. H. BEASLEY SEALING OF CARTONS Filed Jan. 27, 1941 Sheets-Sheet 4 [206% Ef/Bemley per iAfif r/zega Patented June 15, 1943 SEALING F CARTONS Harold Holmyard Bea le i Eng y, Ashton Gate, Bristol, land Application January'zi, 1941, Serial No. 876,207

, In Great Britain February 6, 1940 9 Claims. (Ci. 93-6) This invention relates to the sealing 'of cartons, and more particularly cartons of the type which are impregnated or coated with a sealing substance which can be rendered tacky by heat application, such as for example cartons composed of cardboard or stout paper impregnated or coated with wax to render them waterproof, the sealing being effected by softening the wax in proximity to the mouth and then pinching opposed sides of the mouth together. A form of carton to which the present invention is most appropriately applicable is that which when closed has a wedge-shaped upper part obtained by two opposed inverted Y-shaped folds which enables two sides to be converged or pinched together and united at the mouth by heat sealing. One of such sides can have a flap which can be folded over the other side to form a positive closure and a treble thickness at the mouth. Cartons of this type can have a cylindrical or rectangular body part with a wedge-like upper part, and in practice it is advantageous to adopt the rectangular form as it can be stacked and maniP- ulated quite conveniently. .The heat sealing of cartons of this character has previously been proposed by passing them from a heating stage into acombined cooling and pinching stage so that in each stage a number of cartons are bein treated simultaneously. In one such heretofore proposed method the heating and the combined pinching and cooling is effected by pinching the cartons between the opposed parallel tracks of a pair of endless bands for each stage, the cartons passing from between one pair of bands to the other pair of bands in succession in a continuous manner. tion is to obtain a highly positive treatment of each carton individually over a protracted period by a method which ensures a rapid rate of supply of cartons to be sealed andanother object of this invention-is to provide mechanisms for sealing cartons in which simultaneously a number of cartons are receiving individually distinctive operations appropriate to folding, heating and sealing, so that cartons'can be fed successively at a relatively high rate to and from the mechanism. According to this invention a method of heat 'sealing cartons in which the waxy or like coating or impregnant of the cartons is softened by heat treatment to obtain tacky areas which are pinched together and cooled to re-harden the tacky areas, is characterised in that each carton is passed through-the heating stage and thereafter the cooling and pinching stage by a plurality of intermittent movements in each stage and that during each -stationary period a heated carton is automatically displaced from the heating stage into the cooling and pinching stage simultaneously with the feeding of a non-heattreated carton into the heating stage, each carton being continuously treated in each stage during a succession of stationary and moving periods. I

In a preferred form of this invention, a carton sealing machine has three treatment stages, i. e. initially or partially closing, heat softening of the adhesive medium and then sealing. Combined with these stages is an automatic feeding or the unsealed cartons from a conveyor to the initially or partially closing stage, and means for automatically discharging the sealed cartons on to a collecting conveyor. a

In carrying one form of the invention into practice a carton sealing machine suitable for sealing cartons of the type adapted when closed to have the said wedge-like upper parts, com- The chief object of the present invenprises a number of rotary carriers each having associated therewith distinctive carton treatin means, a conveyor for delivering open cartons successively to one of the carriers, and another conveyor for conveying away the sealed cartons, the carrier which receives the open cartons having hoods provided therewith adapted to be engaged with the open upper end of the cartons to fold them into a closed or wedge-like form, means transferring the cartons from such rotary carrier to another of the rotary carriers provided withheating means for softening the wax or i other sealing medium of the cartons, means transferring the cartons from this heating stage to a further one of the said carriers provided with means for pinching together and cooling the mouth parts of the cartons to eifect a final sealing operation, and means discharging the cartons successively from the latter carrier to a discharge conveyor, the arrangement being that the carriers are rotated simultaneously in an intermittent manner and that all of the said transferring operations and also the folding of the carton mouths by the hoods are effected simultaneously during the stationary periods of the carriers.

The said transferring operations can be effected by a number of pushers, the pushers being carried by slides operated-simultaneously by a common operating member through the medium of cables, the said hoods which fold the carton tops being arranged equidistantly apart above the appropriate carrier and manipulated successively by a reciprocating member operated from a rotary member such as e. g., a cam. Suitable means is provided to screen the predominating portion of each carton from the heating means, particularly when, as would generally be the case, the cartons are of the wax impregnated or coated class. However, the invention is applicable to cartons which have only a narrow section coated with a-substance capable of being rendered adhesive by heat treatment solely for sealing purposes.

In order that this invention may be clearly understood and readily carried into effect drawings are appended hereto somewhat diagrammatically illustrating embodiment thereof, and wherein:

Fig. 1 is a side elevation view partly in section.

Fig. 2 is a plan view with the overhead framework removed.

Fig. 3 is a side elevation showing the means for operating the pusher members.

Fig. 4 is a plan view of Fig. 3.

Fig. 5 is a broken sectional elevation view to a larger scale showing the carton top heating and pinching appliances.

Fig. 6 is a detail elevational view to. a larger scale showing one of the hoods engaged with the top of a carton.

Fig. '7 is a side elevation view of Fig. 6 and showing the ingress and egress stages of a carton relatively to a hood.

Fig. 8 is a broken diagrammatic plan view showing the means for operating the members which pinch and seal the cartons.

Fig. 9 shows in broken perspective a carton after its top has been closed by the machine, and

Fig. 10 is a. detail sectional end elevation View of one of the heating devices with the upper part of a carton shown in broken lines.

Referring to the drawings, in the appropriate parts thereof the cartons are.indicated by the reference numeral I, and the conveyer which carries the open cartons to the machine is indicated by the reference numeral 2, the discharge conveyer being indicated by the reference numeral 3. The machine frame is indicated by the reference numeral 4. Upon this frame are mounted three rotary carriers 5, 6 and I which respectively carry the means appropriate to (1) folding the tops of the cartons, (2) heating such tops to soften the wax in proximity to the mouths, and (3) pinching and cooling the mouths to seal them.

By reference to Fig. 2 it will be seen that the carriers 5 and 6 are rotated anti-clockwise and the carrier 1 clockwise. This rotation is intermittent, the intermittency being effected by a geneva cross rotary member 3 driven by a primary wheel 9 carrying the pin 9:: to engage the radial slots 8a of the member 8. The member 8 is fixed on a vertical shaft 10 which carries a gear wheel ll meshing with a gear wheel i2 driving the carrier 5 and with a gear wheel 5a driving the carrier 6, the gear wheel 6a meshing with a like gear wheel la driving the carrier 1 (see Fig. 5) thus ensuring simultaneous movements of the rotary carriers 5, 6 and I.

- Each movement of 90 of the carrier 5 brings opposite the discharge end of the feeding conveyor 2 a hood 13, there being four of these hoods. A pusher bar It operated by means hereinafter described is, during the stationary periods of the carrier 5, moved across the discharge end of the conveyor 2 to displace a carton onto the carrier 5 immediately beneath the adjacent hood. This hood is then urged downwardly a predetermined amount and in doing so it folds in the open upper end of the carton to 213; closed condition as more clearly shown in Each hood I3 is an inverted V section member, the two limbs Ba and l3b being joined at the inner end by an endplate I30 the other end being open so that at the appropriate stage the carton may be ejected from the carrier 5 on to the carrier 6, this latter stage being that diametrically opposed to the receiving stage (opposite pusher bar. I4) and the displacement of the carton from the carrier 5 being eflected by a pusher bar l5 (see Figs. 3 and 4) which moves in unison with the pusher bar It so that there is a simultaneous loading and discharging of cartons at each'stationary period of the carrier 5.

The sliding movement of each'carton beneath a hood l3 on to the carrier 6 can be utilized for the purpose of folding a flap la carried by one side of each carton flush against the other side of the carton month. When a hood i3 descends over a carton the flap la is engaged by a horizontal plate l3d of the hood, this plate projecting uni-laterally from a short vertical extension l3e of the limb I31), the upper edge of the other limb i3a being spaced below the plate 13d (see Fig. 6) to leave the filap in free to engage the plate l3d, at which stage the carton is nearer the axis of the carrier 5 than the periphery of said carrier, i. e., under the inner end of the appropriate hood. When the carton is pushed from under the hood its flap la. is folded inwards by the plate l3d which plate as it approaches its outer end is bent into the vertical plane, this bend being indicated at I3! in Fig. 7.

Supported by a centre column IS on the carrier 6 is an overhead heating chamber I! the base plate Ha of which has formed on its lower face a plurality of radiating narrow channel section bars !8 each shaped to closely engage over a closed upper part of /a carton. At each stationary period of the carriers 5 and 6 one of these channel sections bars is in alignment with the apex of a hood I3 so that a carton is pressed by the pusher bar l5 on to the carrierii and with its peak, or flap closed mouth, engaged in a channel section bar or between a narrowly spaced pair of bars I8 as shown in Fig. 10. These bars I8 are heated by any suitable means, such as e. g. electric heating elements Me, the temperature of the bars, if desired, being regulated by a thermostat 2o.

There are more pairs of heater bars l8 than hoods l3, e. g. twelve to four as shown in Fig. 2,

and the gear ratio of the gear wheels Ii, l2, Ga

and 1a transmitting the drive from the shaft ll to the carrier 6 is such as to ensure the requisite reduction in angle of movement of the carrier 6 relatively to the carrier 5. This enables each carton to be subjected to the influence of heat over a sufficiently lengthy period to adequately soften the wax at the mouth and flap of the carton. Suitable screens or partitions i9 may be provided on the carrier 6 to screen the bodies of the cartons from heat radiating from the bars i8 so that only the mouth parts of the cartons ar softened.

As great an angle of movement as reasonably possible of the carrier 6 is utilised for obtaining the efiective carton heating period, and in the example illustrated (Fig. 2) this angle is 270, the carton discharge point having a pusher bar 2| (see Figs. 3 and 4) which operates in unison with the beforesaid pusher bars l4 and I5 and tions it is provided with .a plurality of radiating pinching devices indicated generally by the reference numeral 22 in Fig. 2. These pinching devices and the gear driving the carrier are arranged so that at each stationary period a heating bar i8 is aligned with a pinching device 22, this being'elear by reference to Fig. 2, the pusher bar 2i reciprocating along this lineof alignment. Another pusher bar 50 operating in a direction at frame 4 to take the arms carrying the pusher appropriate stages.

right angles to the pusher bar 2i, pushes the cartons singly from the carrier end of the conveyor 3.

To more clearly indicate the relative positions of the pusher bars i4, 15, H and 5B, and the carriers 5, 6 and i, the outer tracks of movement of these carriers are indicated in Fig. 4 by the broken circles 5 6 and 1 The hoods i3 reciprocate vertically and when each hood is in the loading position (opposite pusher bar id) it israised to enable a carton to pass easily thereunder. This raising can be effected byany suitable mechanism, such as e. g. a ring 23 with a cam 23a adapted to engage successively the lower ends of four vertically slidable arms 24 each attached at its upper end to the inner end of one of the hOOds l3, these arms as being slidably supported in suitable fixed guides indicated diagrammatically by the reference numeral 25 in Fig. 1. The lower ends of these arms 24 carry rollers which in the lowered position of the hoods rest upon the machined face of the l on to the receiving ring 23 frame and travel in a: circular path. This raising and lowering of the hoods only occupies a Each such device comprises a fixed bar 5| and a,

presser bar 52 arranged radially on the base of the cooling chamber 58 carried above the carrier I on the shaft 5! which carries gear wheel I and the carrier i, each presser bar 52 being slightly spaced therefrom and provided with means tomove it towards and away from the bar 5i at the A cover plate 51 closes the top of the cooling chamber 58.

The closed or pinching stage of each pair of bars 5i and 52 occupies nearly the whole of the travel between the pusher bars 2i and 50, i. e. nearly 270 so that there is a protracted sealing period as compared with the relatively short loading intervals appropriate to the delivery of open cartons from the conveyor 2 into the machine.

Each presser bar 52 can be actuated by a cam or eccentric 53 on the lower end of a spindle 56, the upper end of which carries a V-shaped lever 55 one end of which has anchored to it one end of a coiled tension spring 53 which applies the sealing pressure to the presser bar 52 and each such spring is anchored at its other end to the top'o'f one of the spindles 5 as shown in Fig. 2. The other end of this lever 55 carries a roller 59 adapted when the appropriate presser bar 52 reaches the unloading position opposite the pusher bar'50 to engage one end of a fixed cam plate 60 which extends to a point Just beyond the loading stage opposite the pusher bar 2 i. By

a this means the presser bars 52 are held away from short time-and occurs whilst the carrier 5 is stationary. The descent of the hoods is assisted y springs 28. v

The pusher bars l4, I5, 2! and 50 can be operated from a common cam 33 (see Figs. 3 and 4) engaged at its perimeter by a lever 34 to one end of which are anchored a pairof cables 35 and 36 which are passed over pulleys 35a and 36a respectively. The cable 35 is guided over a further pulley 35b and anchored to a sleeve 31 slidable on a fixed guide rod 38, a strong coiled tension spring 39 yieldingly opposing the pull of the cable 35 and maintaining the cable constantly under tension. The sleeve 31 carries a cranked arm 40 which has adjustably fixedto its free end the pusher bar l4.

The other cable 36 operates the pusher bars i5, 2| and 50. The pusher bar 2i is carried by an arm 4| attached by a cranked extension 4la'to a sleeve 42 slidable along a fixedguide rod 43, and the pusher bar 50 is carriedby an arm 44 fixed to a sleeve 45 slidable at one end on a guide rod 45 and suitable guided at its other end. The cable 36 is passed over pulleys 36b, 36c'and 36d and then threaded through and secured to an arm 42a fixed to the sleeve 42 of the pusher bar 2|; and is carried beyond this; arm 42a over a pulley 36c and then anchored to the sleeve 45. The pusher bar i5 is also affixed to the sleeve 45. A strong coiled tension spring 41 yieldingly opposes the pull of the cable.36 and returns the pusher bars l5, 2i and so to their retracted posibe provided to take up any slack that might arise in the the fixed bars against the influence of their springs 55 for just over 90 of the travel of the carrier 1 to enable loading and unloading of the cartons to be eflectedin connection with the carrier 1. It is of course understood-that the numbers of springs 56 with their levers 55 correspond in number to the number of pinching devices.

Any suitable cooling medium may be located in or circulated through the cooling chamber 58, 7

this chamber being supported by the shaft which carries the rotary carrier 1.

It will be apparent from the foregoing that a high rate of supply of open cartons to and fromthe machine can be obtained with a relatively protracted period for' adequately sealing the cartons, means to depress the hoods to fold the cartons into a closed or wedge-like form, means to engage and push the cartons from under such hoods to another of the rotary carriers, heating means located abovesald latter rotary carrier for 35 and 38. Slots 48 are provided in the machine softening the wax or other sealingjmedium of the cartons, means to engage and push the upper parts of the cartons from this heating means to a further one of the-said carriers, pinching devices above said further one of said carriers for pinching together the mouthparts of the cartons to effect a final sealing operation, means discharging the cartons successively from the latter carrier to said discharge conveyor, means rotating the carriers simultaneously in an intermittent manner and mechanism for operating all of the said carton pushing and discharging means simultaneously during the stationary periods of the carriers.

2. In a machine for heat sealing cartons having a carton top closing mechanism and heating and pinching mechanisms, said top closing mechanism comprising a set of hoods, an inverted V- shaped carton top engaging part on each hood adapted to impart a wedge-like shape to each carton top, means to feed the cartons under the hoods, means to raise and lower the hoods, and flap closing means on each hood comprising an abutment projecting laterally beyond the upper part of one limb of each inverted V-shaped hood part over the other limb and bent through substantially 90 at one end, through which end the cartons are discharged from the hood into the heating mechanism.

3. In a machine for heat sealing cartons, an initial carton top closing mechanism, a carton top heating device and a carton top pinching and cooling appliance, three rotary carriers carrying said mechanism, heating device and carton top pinching and cooling appliance each adapted to carry a plurality of cartons simultaneously, means to feed the cartons singly from one carrier to another, said means to pinch and cool the carton tops comprising a top member disposed above and carried by the rotary carrier of the pinching and cooling appliance, a plurality of radiating pairs of pinch bars carried by the base of said top member, means to automatically pinch together each pair of said pairs of bars after feeding between them a carton, a carton collecting device, means to successively separate each pair of the pairs of pinch bars when the appropriate carrier locates a carton opposite said collecting device, and means automatically pushing the cartons in succession from said pinch bars on to said collecting device.

4. In a machine for heat sealing cartons a number of rotating carriers each adapted to support a plurality of cartons simultaneously and having associated therewith distinctive carton treating means and comprising a first rotary carrier adapted to receive singly successively open cartons, means with said carrier automatically folding the tops of the cartons to a closed condition, a second rotary carrier, means automatically transferring the closed top cartons successively to the second rotary carrier, heating means with said latter carrier to render the tops of the cartons adhesive, a third rotary carrier, pinching devices on said third carrier means adapted to automatically transfer the cartons singly successively fromthe second carrier to the pinching devices on the third rotary carrier to pinch the adhesive carton tops and cool them to effect a sealing operation, and means automatically delivering the sealed cartons in succession from the latter carrier, gearing connecting the rotary carriers in a train and imparting intermittent simultaneous rotation to the carriers, said means automatically transferring the cartons from one carrier to another comprising pusher members operating in unison during the station.- ary periods of the carriers to engage and push cartons singly from each carrier so that a number of cartons are transferred simultaneously across the diiferent carriers and'a plurality of cartons are heat treated and a plurality pinched and cooled simultaneously.

5. In a machine for heat sealing cartons a number of carton supporting carriers, and carton supply and discharging conveyors to supply car tons to and remove them from the machine, means with each of said carriers for applying an operation appropriate to a sealing treatment to a number of cartons simultaneously for each delivery of an unsealed carton to the machine, a set of carton receivers on each carrier, means to traverse the carriers intermittently in unison, and means automatically operating during the stationary periods of the carriers to feed a carton from the supply conveyor to one of the carriers and to feed a sealed carton from another of the carriers.to the conveyor removing cartons from the machine.

6. A machine for heat sealing cartons comprising a movable carrier adapted to receive singly successively open cartons, carton top folding means located above said carrier and adapted to engage and automatically fold the tops of the cartons on the carrier to a closed condition, a second movable carrier, means automatically transferring the closed top cartons successively from the first to the second movable carrier, heating members supported above said latter carrier and adapted to receive the tops of the cartons to render them adhesive by heat, a third movable carrier, pinching devices on said latter carrier adapted to pinch the carton tops, means adapted to automatically transfer the cartons singly successively to said third carrier and pinching devices from the said second carrier, means automatically discharging the sealed cartons in succession from the said third carrier, and means automatically opening the pinching devices when they receive and are freed of cartons and automatically pinching them on to the cartons between such receiving and discharging operations.

7. In a machine for heat sealing cartons a number of rotating carriers each adapted to support a plurality of cartons simultaneously and having associated therewith distinctive carton treating means and comprising a first rotary carrier adapted to receive singly successively open cartons, means on said first carrier automatically folding the tops of the cartons to a closed condition, a second rotary carrier, pusher members automatically transferring the closed top cartons successively to the second rotary carrier, heated guides to receive the carton tops on said latter carrier to render the tops of the cartons adhesive by heat, a third rotary carrier, carton top engaging and pinching devices carried by the said third carrier and means opening and closing said devices relative to said third carrier, means adapted to automatically push the cartons singly successively to the said pinching devices, and means automatically delivering the sealed cartons in succession from the latter carrier, said means folding the tops of the cartons to a closed condition comprising inverted substantially V-shaped hoods and means to lower each hood over a carton so as to fold to a wedge-like form the top of the carton and to raise the hood to receive a new carton.

8. In a machine for heat sealing cartons a plurality of distinctive treatment apparatus operating in unison, comprising a set of hoods, each hood having an inverted V-shaped carton top engaging portion, means to raise and lower the hoods, traversing means operating relative to the treatment apparatus to traverse the open cartons the hoods when the hoods are raised, further traversing means operating simui taneously with the beioresaid traversing means to initial carton top closing mechanism and heatingand pinching mechanisms rotary carriers, a set of hoods incorporating three on one of top pinching and cools Y asamsa I carriers from a common axis of rotation, vertically recinrocatlns m mbers sin traverse the cartons from under the hoods when position, carton feeding t nism when the hoods are lowered. said heating porting; said hoods. inverted v-ghaped carton top enga ing parts forming of said hoods,

means engaging and lifting said members successively, meansfor feeding the cartons under the hoods when the hoods are raked-,means for the cartons singly to'thf heating mechamechanism including one of said rotarycarriers. a cover on said latter carrier, a plurality oi channel-like heating members on the cover' memher radiating from the axis 61' rotation of its carrier; means automatically 'iiedlng the heated cartons successively to the pinching mechanism,

and cooling means with said pinthing mechanism;

HAROLD HOLMYARD B EASLEY.

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