Self-adjusting closing machine for parallelepipedal boxes of varying format

A detecting member for the height of the box with open side flaps is mounted in a vertically variable position on the closing assembly for the top flaps and is connected mechanically to the drive device which draws together the box conveyance units. In this manner drawing together of the conveyance units until they engage the sides of the box causes a corresponding movement of the detecting member which arranges itself in a position dependent upon the width of the box. Fall of the closing assembly starts simultaneously from a raised neutral position and continues until engagement of the detecting member so arranged with the top of an open side flap of the box. Braking means then stop the fall of the closing assembly. Appropriate sensitive means start operation of the closing assembly for the rear flap on the basis of the box length.

The present invention relates to a self-adjusting closing machine for 
parallelepiped boxes of varying format. 
A known packing system calls for the use of parallelepiped cardboard boxes 
which after filling are closed at the top by means of folding flaps sealed 
with strips of adhesive tape. More precisely, said boxes comprise a front 
flap and a rear flap folding first and two side flaps folding thereafter 
without mutual superimposition. Between the two folded side flaps there is 
described a narrow longitudinal separating fissure arranged centrally 
along which there is finally applied from one end to the other of the box 
the strip of sealing adhesive tape. 
Various machines are known for automatic closing in succession of the top 
flaps of boxes having a fixed format. They only require an initial 
adjustment based on the width and height of the box and then are ready to 
operate repetitively on a plurality of boxes of the same format. 
Problems arise when the boxes are of varying format since it is not 
practicable to regulate the machine for each box fed. 
Socalled "self-adjusting" machines are known which through appropriate 
members measure the width and height of the boxes and on the basis thereof 
automatically vary the position of the closing members. 
Some of these are based on the concept that the height of the open side 
flaps of the box is equal to half the width of the box so that by 
measuring said width and the total height of the box with side flaps open 
and substracting the first result from the second it is possible to find 
the height of the box with closed flaps and hence the vertical position 
required for the closing members. 
Said concept is undoubtedly valid but the machines obtained have proved 
rather complicated and/or inaccurate so that they have met with little 
practical application. 
The object of the present invention is to achieve a closing machine for 
parallelepiped boxes of varying format which in a simple and functional 
manner would be capable of taking the dimensions of the box and 
automatically adapting thereto the position of the closing members. 
In accordance with the invention said object has been achieved by a 
self-adjusting closing machine comprising a supporting table for the 
boxes, a pair of belt conveying units extending along opposing sides of 
said supporting table, means for drawing together said conveying units 
until the corresponding opposing sides of the boxes are engaged thereby, a 
closing assembly for the top flaps of the boxes which may be arranged at 
variable height above said supporting table and adjusting means for 
automatically regulating said variable height of the closing assembly 
based on the format of the boxes characterized in that said adjusting 
means comprises a member for detecting the height of the boxes with side 
flaps open mounted in a vertically variable position on said closing 
assembly, means for modifying the vertical position of said detecting 
member in relation to a raised neutral position, a mechanical transmission 
placed between said means of drawing together the conveyance units and 
said means for modifying the vertical position of said detecting member in 
such a manner as to prearrange said detecting member in a lowered position 
at a distance from the base of said closing assembly equal to half of the 
width of the box, first sensitive means which respond to the engagement of 
said conveyance units with the sides of the box in such a manner as to 
control the free descent of said closing assembly from a raised neutral 
position to a maximum height above said supporting table, means for 
braking the descent of said closing assembly, second sensitive means which 
respond to the engagement of said detecting member with the top of an open 
side flap of the box and advancement of said conveyance assembly for 
further travel of the box, and third sensitive means which respond to said 
further travel of the box to control operation of said closing assembly 
for closing of the rear flap of the box. 
This is essentially a machine which uses the known principle of 
substracting half the width of the box (equal to the height of an open 
side flap) from the total height of the box with side flaps open by 
initial setting of the total height detecting member in a position based 
on the width of the box. It is distinguished however from known machines 
which make use of said principle by the type of functional connection 
employed between the means for drawing the conveyance assembly together 
and the means for modifying the position of the detecting member as well 
as by the manner of moving and stopping the closing assembly. The use of a 
mechanical transmission with appropriately predetermined ratio allows 
reliable presetting of the detecting member precisely in the desired 
position with no possibility of error and with full repeatability. The 
free fall movement of the closing assembly and the employment of braking 
means constitute at the same time a very simple and accurate manner of 
correctly positioning the closing assembly. 
Preferably the machine in accordance with the invention also requires that 
said third sensitive means comprise a first and a second sensitive element 
arranged along said supporting table in such a manner as to be met 
successively by the advancing box, said sensitive elements being 
operationally connected together and with said closing assembly in such a 
manner that operation of said closing assembly for closing of the rear 
flaps of the box is caused alternatively by abandonment of the first 
sensitive element if the box has already encountered the second sensitive 
element or by meeting with the second sensitive element if the first 
sensitive element has been abandoned before the box has met the second 
sensitive element. 
In this manner the behaviour of the closing assembly and in general of the 
machine as a whole changes automatically with the length of the box. A 
long box when abandoning the first sensitive element while the second is 
still engaged by the same box causes operation of the closing assembly 
with the rear part of the box still to the rear while a short box, being 
linked to the encounter with the second sensitive element when the first 
sensitive element has already been abandoned, causes retarded operation of 
the closing assembly on the rear part of the advanced box so as to prevent 
interference between the closing of the rear flap and the closing of the 
front flap. 
Preferably it is also provided that operation of the closing assembly be 
accompanied by a momentary stop of the box, i.e. with the box stationary 
instead of moving. This allows more reliable and accurate closing of the 
rear flap.

The machine illustrated in the drawings comprises a bed 1 which supports a 
succession of parallel idling rollers 2 forming a supporting table for the 
boxes. 
Along two opposite sides of said supporting table there extend two 
motor-driven belt conveyance units 3 (of known type) which are drawn 
together from a neutral position shown in unbroken lines in FIGS. 2 and 4 
to the nearest position illustrated in dot and dash lines in FIG. 4 until 
they engage for conveyance the corresponding opposite sides of the box 
(FIGS. 12, 13 and 15). 
Motor drive of the belts of the two conveyance units is provided by a motor 
assembly 4 of known type (FIG. 2) which allows drawing together and apart 
of said units. A clutch (not shown) of the type described in Italian 
patent application No. 19289 A/82 by the same applicant is placed between 
the motor 4 and the belts to allow momentary stopping of the belts when 
desired. 
Drawing together and apart of the conveyance units 3 is due to a drive 
device 5 (FIGS. 3 and 4) also known which comprises essentially a drive 
cylinder 6, a sliding body 7 fixed to the stem of the drive cylinder 6 and 
equipped with opposing sides 8 shaped like a rack, a pair of sector gears 
9 fixed on turning pins 10 and engaged with said opposite sides of the 
sliding body 7, two pairs of swinging arms 11 fixed to said pins 10, two 
pairs of connecting rods 12 and finally two pairs of slides 13 which slide 
on two guide bars 14 and bear at the two ends of the machine the 
conveyance units 3. For further details reference is made to Italian 
patent application No. 19288 A/82 filed Jan. 26, 1982 of which the same 
applicant is holder and the description of which is to be considered 
incorporated herein. 
A pair of pneumatic valves 79 (FIG. 3) is associated with the conveyance 
unit 3 to detect engagement thereof with the sides of the boxes. 
From the same sides of the bed 1 there extend upward two pairs of columns 
15 and 16 which act as sliding guides for corresponding vertical slides 17 
and 18 (FIGS. 1, 2 and 4) which extend downward from a pair of integral 
crosspieces 19 and 20 which form part of a closing assembly 21 for the top 
flaps of the boxes which is placed above the box-supporting table at a 
variable height in the manner described below. 
The closing assembly 21 comprises a supporting frame 22 which includes the 
two crosspieces 19 and 20 and supports a closing device for the end flaps 
23 (FIG. 1), a pair of closing screws for the side flaps 24 (FIG. 4), a 
flap holder 25 and a taping unit 26 (shown only schematically in FIG. 1). 
The device for closing the end flaps 23 is of the type described in Italian 
patent application No. 21011 B /85 filed Mar. 6, 1985 of which the same 
applicant is the holder and comprises essentially a first closing member 
27 for the front flap (in the direction of travel of the box from right to 
left as seen in FIG. 1) and a second closing member 28 for the rear flap, 
associated with a single rotating support 29 made in the form of a boxed 
disc extending for substantially three-fourths of a circle and pivoted at 
30 on one end of the supporting frame 22. The closing member for the front 
flap 27 consists of a pair of curved bars born by one end of the rotating 
support 29 while the rear-flap closing member 28 consists of an extension 
31 of the rotating support 29 on which is pivoted at 32 a blade 33 on 
which a spring and a flexible strip of fixed length (neither shown) act in 
such a manner as to hold it within the space occupied by the extension 31 
when the rotating support 29 is in the neutral position of FIG. 1 and 
force it instead to rotate and emerge from said space occupied to the 
working position of FIG. 10 in reaction to the rotation of the rotating 
support 29 from the position of FIG. 1 to that of FIG. 10. For better 
understanding of the device 23 reference is made to the aforesaid patent 
application the description of which is to be considered incorporated 
herein. 
To rotate the disc support 29 there is provided a compressed air cylinder 
34 which reacts between a pair of brackets 35 fixed to the crosspiece 19 
and a pair of straight rods 36 pivoted at excentric points 37 of the sides 
of the rotating support 29. 
The two side-flap closing screws 24 are of the type described in Italian 
patent application No. 19788 A/85 filed Mar. 6, 1985 the holder of which 
is the same applicant and the description of which is to be considered 
incorporated herein. It is important to note that in conformity with the 
aforesaid patent application the two screws are shaped in such a manner as 
to permit closing of the side flaps of boxes of different widths with no 
need of side adjustment. 
The flap holding device 25 which constitutes the lower base of the closing 
assembly 21 is also well known in the art and comprises a longitudinal 
overturned-T section attached to the overstanding supporting frame 22 by 
means of two parallel rods 39 and 40 which support it in a slightly 
inclined position (higher at the box inlet end and lower at the outlet 
end) as shown in FIG. 1. The rods 39 and 40 are affixed rigidly to the 
overstanding frame 22 while a pin 76 in a cylindrical hole and a pin 77 in 
a vertically lengthened slot 78 connect in an articulated manner said rods 
39 and 40 to the section 38 in such a manner as to allow the entering box 
to partially or completely compensate for the inclination of the section 
38. A compressed air valve 73 is fixed to the frame 22 to detect the 
lifting of the rear part of the section 38 to the horizontal position of 
said section. 
The taping unit 26 is associated with the rear end of the supporting frame 
22 beyond the crosspiece 19 and is for example the type illustrated in 
Italian patent application No. 23191 A/84 filed Oct. 17, 1984 of which the 
holder is the same applicant and the description is to be considered 
incorporated herein. 
As mentioned above the closing assembly 21 is placed at a variable height 
above the box supporting table. Movement thereof is guided by cooperation 
of the slides 17 and 18 with the fixed columns 15 and 16 and is raised by 
compressed air cylinders (not shown) reacting between the lower ends of 
the slides 17 and 18 and the columns 15 and 16 and is lowered by the 
weight of the closing assembly. To stop the closing assembly 21 in any 
desired position in the course of its descent there is provided a pair of 
braking clamps 41 operated by compressed air (FIGS. 2 and 3) which 
cooperates with vertical rods 42 coupled in a sliding manner with the 
supporting 22 of the closing assembly 21 with interposed springs 43 to 
push the frame 22 back upward. Single-acting compressed air cylinders 69 
with limited travel 69 (FIGS. 1 and 3) also act on the frame 22 to cause 
when required a limited and temporary rising of the frame 22 as will be 
better explained below. 
To determine from time to time the correct vertical position of the closing 
assembly 21, which must be such that it places the flap-holding device 25 
substantially even with the top of the box with end flaps closed to hold 
the latter in the closed position during the closing phase of the side 
flaps and until application of the sealing adhesive tape, there is 
provided a detecting device 44 for measurement of the total height of the 
box with open side flaps which cooperates with the drive device 5 for the 
drawing together motion of the conveyance unit 3 to subtract from said 
total height half of the box width which is equal to the height of the 
open side flaps. 
As better shown in FIGS. 5-7 the aforesaid detecting member 44 consists of 
a cylindrical bar mounted in a freely turning manner on one end of a 
supporting arm 45 pivoted at 46 and further restrained in an adjustable 
manner by an adjusting screw 47 to a fork support 48 made integral with a 
drum 49 mounted in a turning manner through a bush 50 on a shaft 51. The 
weight of the fork support 48, of the arm 45 and of said detecting member 
44 holds the entire described assembly in a predetermined angular position 
against a ratchet 52 fixed to a turning disc 53 made integral with the 
shaft 51 (FIG. 7) and fitted with a spring 54 attached to the crosspiece 
20 to take up play. A compressed air valve 56 supported by a supporting 
bracket 57 fixed to the disc 53 (FIGS. 5 and 6) collaborates with a notch 
58 in the drum 49 to detect movements of said drum and of the assembly 
fixed thereto relative to the angular position set by the screw 47. A 
blocking head 59 operated by a compressed air cylinder 60 fixed by a 
bracket 61 to the frame 22 (FIGS. 5 and 6) is in turn capable of pressing 
on the side wall of the drum 49 to prevent rotation thereof when necessary 
as will be explained better below. Alternatively the blocking head 59 may 
be replaced by a mechanical connection capable of acting on the drum 49 to 
slightly lift the detecting member 44 in relation to the predetermined 
position. 
As shown in FIGS. 6 and 7 the shaft 51 is connected by a bevel gear pair 62 
and 63 contained in a box 64 supported by the frame 22 to a vertical 
telescopic shaft 65 to the lower end of which is fixed a gear 66 (FIGS. 
1-3) connected by a chain 67 to two gears 68 mounted on the connecting 
pins 10 which join the sector gears 9 to the swinging arms 11 of the drive 
device to provide the movements of drawing together and apart of the 
conveyance units 3. In this manner the position of the detecting member 44 
is made dependent upon the width of the box as will be clarified below. 
Lastly, the machine illustrated in the drawings includes along the 
box-supporting table four detecting levers 70, 71, 100 and 72 which detect 
the state of travel of the box and act on respective compressed air valves 
in such a manner as to create a predetermined sequence of operations of 
the various devices described. A stop rung 74 operated by a compressed air 
cylinder 75 is placed before the lever 71 to act as a positioning element 
for the box at the beginning of the closing cycle. A valve 200 attached to 
the bottom of the column 15 cooperates with a rod 150 attached in an 
adjustable position to the closing assembly 21 to establish a maximum 
height for said closing group 21. 
A suitable compressed air control circuit for the various functions of the 
machine is illustrated in FIG. 16 and comprises the compressed air 
cylinder 34 for control of the closing device for the end flaps 23, the 
control cylinder 6 for drawing together and apart of the conveyance units 
3, the control cylinder 75 for the stop rung 74, a control cylinder 101 
for the brake clamps 41, a control cylinder 102 for the clutch placed 
between the motor 4 and the conveyance units 3, the cylinder 60 for 
control of the blocking head 59 (or a substitute member) associated with 
the detecting member 44, a cylinder 103 for lifting the closing assembly 
21 and the limited travel cylinders 69 assigned to correction of the 
height of the closing assembly 21. 
The control circuit of FIG. 16 also includes four valves 104, 105, 106 and 
107 operated by the detecting levers 70, 71, 100 and 72, the 
aforementioned maximum height valve 200, the aforementioned valve 56 for 
detecting the rotation of the drum 49 associated with the detecting member 
48, the valves 79 for detecting engagement of the conveyance units 3 with 
the sides of the boxes, the valve 73 for control of the cylinders 69 and a 
valve 110 controlled by an emergency pushbutton (not shown) capable of 
causing immediate opening of the machine if necessary. 
Finally, there are provided some distributors indicated by numbers 121-129, 
a pressure regulator 130, two flow regulators 131 associated with the 
cylinders 69 and two 3-way connecting elements 132 and 133 (each with a 
check valve 134, 135 on one of the ways) with the second of which is 
associated a pressure regulator 136. 
The control circuit of FIG. 16 in combination with the structure described 
in FIGS. 1-15 brings about the following type of operation. With the 
machine in the neutral position shown in FIG. 1, i.e. with the closing 
assembly 21 in the highest position, with the device 23 rotated as shown 
in FIG. 1 and with the detecting member 44 in the raised neutral position 
adjustable by means of the screw 47 (positions illustrated in solid lines 
and in dot and dash lines in FIG. 4) the boxes 80 are fed manually or 
mechanically onto the bed 1 with all the top flaps open as shown in FIG. 
8. In this and the following figures the side flaps are indicated by 
number 81, number 84 indicates the bottom of the box, number 85 indicates 
the front wall thereof, number 86 indicates the rear wall thereof, and 
number 87 indicates the sides thereof. The direction of travel of the box 
is from right to left when viewing FIGS. 8-15. 
The closing cycle starts when the bottom of the advancing box after 
pressing the lever 70 without causing changes of state reaches the 
positioning rung 74 and simultaneously presses the lever 71 (FIG. 8). The 
valve 105 then commutates (FIG. 16) which causes commutation of the 
distributor 122 into a position such as to allow the cylinder 6 to drive 
through the sliding body 7, the sector gears 9, the pins 10 and the 
swinging arms 11 the approacing of the conveyance units 3 until they 
engage the sides of the box (FIG. 12). In this situation a pair of 
vertical columns 90 (FIGS. 1 and 4) fixed on the conveyance units 3 holds 
the side flaps 83 of the box in the vertical position preventing outward 
spreading thereof. This condition is maintained to allow correct detection 
of the total height of the box with the side flaps open in accordance with 
the procedures explained below. 
Simultaneously through the mechanical transmission formed by the gears 68 
and 66, the chain 67, the telescopic shaft 65 and the bevel gear pair 63, 
62, the rotation of the sector gears 9 is transmitted to the shaft 51 
(FIGS. 5-7) which causes integral rotation of the disc 53 and of the drum 
49 and then that of the interconnected supports 48 and 45 in the direction 
of lowering of the detecting bar 44. The transmission ratio and the 
initial adjustment of the screw 47 are selected in such a manner that in 
its final position the bar 44 is at a distance vertically from the base of 
the flap-pressing section 38 equal to half the width of the box which is 
in turn equal to the width of the side flap 8, i.e. to their height in the 
open position. Said position is illustrated in FIG. 8. 
Engagement of the conveyance units 3 with the sides of the box is detected 
by the compressed air valves 79 (FIGS. 2 and 3) which through Ccommutation 
of the distributors 123 and 128 control raising of the stop rung 74 and 
deactivation of the raising cylinder 103 of the closing assembly 21 to 
allow the resulting fall by gravity of said rung assembly. 
The fall stops when the detecting member 44 rests upon the nearest open 
side flap of the box (FIG. 9) causing thereby a small rotation of the 
support 45, 48 and of the turning drum 49 relative to the fixed disc 53 
and the shaft 51. Said rotation is detected through the notch 58 of the 
compressed air valve 56 (FIGS. 5 and 6) which controls the action of the 
cylinder 60 for advancement of the rung 59 until it engages in a blocking 
manner with the cylindrical wall of the drum 49 (or for limited lifting of 
the detecting member (44) and also controls through the cylinder 101 the 
action of the brake clamps 41 for stopping the fall of the closing 
assembly 21 and through the cylinder 102 that of the clutch associated 
with the motor assembly 4 for operation of the conveyance belts of the 
units 3. 
In consideration of the previous setting of the detecting member 44 at a 
distance from the base of the section 38 equal to the height of the open 
side flaps and of the detection now executed by said member 44 of the 
total height of the box with open flaps, stopping of the fall of the 
closing assembly 21 takes place in such a position that the distance 
between the raised front end of the base of the section 38 and hence of 
said closing assembly 21 and the box-supporting table is exactly equal to 
or slightly greater than the actual height of the box with end flaps 
closed. 
In this manner while the closing assembly 21 stops in the position shown in 
FIG. 9, slightly compressing the springs 43 to then be pushed back thereby 
into the correct position, the front or inlet end of the flap-holding 
device 25 is in a position such as to allow entry of the box, which is 
drawn forward by the conveyance units 3, which are now motor driven. The 
stop rung 74 has meanwhile been made to return within the space occupied 
by the bed 1. 
From this moment onward there begins the cycle of closing of the top flaps 
of the box the performance of which depends on the length of the box. If 
the box is short as shown in FIGS. 8-13 said box advances freely until it 
encounters the lever 100 after abandoning the lever 70. Consequently first 
the front flap 81 engages the bars 27 and is overturned thereby into the 
closed position and then, at the moment of the engagement with the lever 
100 (FIGS. 10 and 13) and the consequent commutation of the valve 106, the 
cylinder 102 is returned to neutral for the release of the clutch device 
controlling the conveyance units 3 and the resulting momentary stopping of 
the travel of the box and the cylinder 34 controlling the closing device 
23 is activated for closing of the rear flaps 82 of the box. More 
precisely, the cylinder 34 causes rotation of the disc support 29 in such 
a manner that the extension 31 causes an initial closing overturn of the 
rear flap 82 and then the blade 33, rotating by reaction of a fixed-length 
tape in accordance with the operations explained in the aforementiond 
Italian patent application No. 21011 B/85 filed Mar. 6, 1985, completes 
closing of said flap (FIG. 10). 
If the box is long as shown in FIGS. 14 and 15 the front flap 81 is still 
closed in conformity with the preceding process but control of the 
rear-flap closing device is provided not by the encounter of the box with 
the lever 100 but by abandonment of the lever 70 with the lever 100 
already pressed. Abandonment of the lever 70 then causes, thanks to the 
distributors 125 and 121 and the cylinders 102 and 34, momentary 
disengagement of the clutch which controls the conveyance units 3 and 
activation of the rear-flap closing device 82 (FIGS. 14 and 15). 
In this manner interference of the closing blade 33 with the front flap of 
the box with the resulting obstruction of the closing of the latter or of 
correct operation of said closing blade is always prevented. 
When the closing operation of the end flaps 81 and 82 has been performed in 
the manner described, after a period of time determined by the distributor 
127, the conveyance units 3 are again started and the box consequently 
enters under the inlet end of the section 38 which is superimposed 
accurately on the front flap 81, holding it in the closing position. 
Continuing to advance the box pushes progressively upward the following 
portions of the section 38 which rotates around the pin 76 to the 
horizontal position (FIG. 11). 
When said position is reached the valve 73 causes through the cylinders 69 
very limited lifting of the closing assembly 21 which lightens if 
necessary the pressure on the top of the box aided therein by the springs 
43 upon which the closing asembly is floating. This prevents possible 
jamming and damage to the box. On this occasion the flow regulators 131 
prevent excessively high adjusting jumps. 
As the box continues its travel, while the base of the section 38 is 
superimposed also on the rear flap 82 of the box, holding it in the closed 
position, the two screws 24 engage the side flaps 83 to cause progressive 
closing rotation thereof. Meanwhile the device 23 has returned to the 
position shown in FIG. 1 driven in said direction by the cylinder 34 
following release of the lever 71. 
With the side flaps 83 closed on the end flaps 81 and 82 the box then 
passes under the taping unit 26 which applies a strip of sealing adhesive 
tape along the longitudinal central fissure which separates the two folded 
side flaps. 
The cycle terminates when the box 80 encounters and then abandons the lever 
72. Release of the latter causes withdrawal again of the conveyance units 
3, lifting again of the closing assembly 21, release of the drum 49 and 
deactivation of the clutch associated with the motor assembly 4. The 
machine then returns to the neutral position. 
The valve 200 together with the rod 150 has the purpose of limiting the 
working height of the machine when the boxes do not require maximum 
height. Furthermore, it has the purpose of limiting the supporting 
pressure of the closing assembly 21 and permitting an immediate response 
to the command to fall.