|Title of Invention||
"DEVICE FOR FOLDING FLAPS OF BOX BLANKS"
|Abstract||This device for folding flaps of box blanks having transverse creasing lines to the travelling direction of the blanks, for folder-gluer, comprise a rotary member around a transverse axis provided with at least one folding arm (6). This device comprises removable linking means (11-13) to a support (10) secured to the frame (B) of the folder-gluer, adjusting means (7, 8, 12, 13) of the position of the said folding arm or arms (6) with respect to the said support (10), a motor (2) for driving the said rotary member and synchronization means of the said motor (2) comprising, on the one hand, an encoder (16) in desmodromic connection with a drive mechanism (9) of the box blanks and, on the other hand, a detector (14) of the passage at a reference position of the box blanks on the folder- gluer. Fig. 2:|
|Full Text||DEVICE FOR FOLDING FLAPS OF BOX BLANKS
The present invention refers to a device for folding flaps of box blanks having transverse creasing lines to the travelling direction of the blanks, for folder-gluer, comprising a rotary member around a transverse axis to the said travelling direction, provided with at least one folding member.
The devices for folding flaps of folding boxes with a folding member mounted on a transverse rotary shaft and comprising a single folder in the shape of a hook are well known. Another well known similar device comprises two hook-shaped folders which are symmetrically arranged with respect to the axis of the transverse rotary shaft. This or these folders are mounted on a central hub which is laterally movable along the transverse rotary shaft. The box blank travels above the rotary folding member and the folders will fold the flap from the rear while the box blank is travelling. Consequently, the folder should move at higher speed than the box blank.
In order to fold the flap, the end of the folding hook must contact the flap to be folded in a favourable area being situated at about two thirds of the flap length taken from the transverse creasing line around which the flap must be folded. The transverse shaft of the rotary folding member is situated at a given distance from the passage plane of the blanks and, in order to work in the favourable area of the flap to be folded, it is necessary to either adapt the length of the hooks or to position shims on the central hub supporting the folding hooks. A device of this kind is described in patent US 3'330'185. The main drawback of this device is the required adjustment time and the difficult positioning of the folding hook in the favourable folding area.
To obviate the drawbacks of the aforesaid solution, FR 2'597'027 describes a device wherein a plurality of motors are controlled by a pulse converter converting the values of the movement curves calculated by a function generator receiving data from a detector of passage of the blanks and the settings relating to the characteristic dimensions of these blanks. Each of these various motors acts according to different degrees of mobility of the device and they allow optimizing the movement of the folding hooks.
However, such a solution is relatively complex and hence expensive. This complexity is mostly due to the fact that the folding device occupies a determined position on the folder-gluer whereas the dimensions of the cardboard blanks may substantially vary. Also possible are blanks having
transversely aligned flaps to fold which are of different lengths. This implies to provide two devices on a common transverse support which are adjusted according to the respective lengths of the flaps.
The object of the present invention is to at least partly obviate the aforesaid drawbacks.
To this aim, the object of the present invention is a device for folding flaps of box blanks having creasing lines that are arranged transversely to the moving direction of the blanks, for folder-gluer, according to claim 1.
This device is simple. It can be mounted on any support adapted to the folder-gluer, which can be positioned inside of any free space in the machine. In fact, the device being entirely autonomous, the support on which it is mounted doesn't have any other function since the device is driven by a motor synchronized with the drive mechanism of the folder-gluer and not directly by this drive mechanism.
As will be seen from the following description, due to its great ease of being mounted wherever is space between the frames of the folder-gluer, this device offers new application possibilities with respect to the prior art folding devices.
The accompanying drawings illustrate, schematically and by way of example, an embodiment of the folding device according to the present invention.
Fig. 1 is a perspective view of the device according to the invention;
Fig. 2 is a perspective view of the device of Fig. 1 mounted on a partially illustrated folder-gluer;
Fig. 3 is a perspective view seen from another angle of the same device mounted on a folder-gluer;
Figs. 4 and 5 are views showing the relative positions of the circular path of the folding arms and of the rectilinear path of the box blanks for folding flaps of different lengths.
The device according to the invention comprises an elongated housing 1 having two large parallel surfaces interconnected by relatively narrow lateral faces. One of the large parallel surfaces of this housing 1 carries a drive motor 2, the shaft of which extends inside of this housing. A toothed pulley 3, situated in the housing 1, is wedged at the end of this shaft. This toothed pulley 3 is engaged with a toothed belt 4 forming an endless loop engaged with a second
toothed pulley (hidden by the walls of the housing 1), secured to a shaft 5 rotating in the walls of the housing 1 and one end of which protruding outside this housing 1. ;
In the present example, the end of the shaft 5 carries two folding arms 6 in the shape of hooks, symmetrically arranged with respect to a plane containing the longitudinal axis of the shaft 5. These folding arms 6 are secured to the shaft 5, so as to be driven by it when the motor 2 drives the belt 4 engaged with the toothed pulley 3. Obviously, by adapting the speed of rotation of the motor 2, the use of only one hook-shaped folding arm would be possible.
The two elongated lateral faces of the housing 1 have-each a dovetail slide 7, 8. These slides 7, 8 are selectively used for mounting the housing on the folder-gluer of which, in Figs. 2 and 3, a portion of two lateral parts of the frame B and of the drive mechanism 9 of the box blanks has been represented, as well as a support crossbar 10 of this device extending between the two lateral parts of the frame B. One of the slides 7, 8 of the housing 1 is intended to receive linking means to the support crossbar 10 which mainly comprise a linking plate 11 associated on the one hand with screw cradles 12 which engage in one of the slides 7, 8 and allow to clamp the linking plate 11 in the required position along the slide 7 or 8. This linking plate 11 further carries, on the other hand, two clamping arms 13 intended to its fixing along the support crossbar 10. This support crossbar 10 has a polygonal section, square in the illustrated example, to allow defining the orientation of the linking plate 11 With respect to the longitudinal axis of the support crossbar 10.
The screw cradles 12 are aligned along an axis that is perpendicular to the axis on which the clamping arms are aligned, so as to form adjustable fixing means in two orthogonal directions.
Owing to the described device, the housing 1 thus has an adjustment possibility according to two degrees of mobility, one transverse with respect to the support crossbar 10 engaged with the clamping arms 13, the other vertical along one of the slides 7, 8 engaged with the screw cradles 12.
In order to ensure synchronization between the drive motor 2, the folding arms 6 and the drive, mechanism 9 of the box blanks in the folder-gluer, the device according to the invention includes a laser cell 14 intended to detect the passage at a precise reference position of a rear edge of each box blank.
This laser cell 14 is connected to a control housing 15 of the drive motor 2 (Figs. 2 and 3). The synchronization means of the device further comprise an encoder 16 connected, on the one hand, by a desmodromic connection to the drive mechanism 9 of the box blanks (i.e. by a connection such that the speed of rotation of the encoder 16 causes a well determined speed for the rotation of the drive mechanism 9) and, on the other hand, by an electrical connection to the control housing 15 of the drive motor 2. The word "desmodromic" is derived from two Greek roots, desmos (controlled, linked) and dromos (course, track). In general mechanical terms, desmodromic refers to a mechanism comprising one or several parts linked so that said mechanism has a single degree of freedom in a way that the speed of one of the parts determines the speed of the other parts.
The collected information allows controlling the motor 2 in a synchronous manner with the forward speed of the box blanks and their passage frequency at the detection place which depends on the length of the box blanks in their travelling direction F in the folder-gluer.
The control housing 15 must further receive information about the characteristics of the blanks in order to ensure programming of the drive motor. This information is introduced by the machine operator. However, the programming mode being not a part of the present invention and hence will not be described here.
As can be easily understood from the previous description, the described folding device operates autonomously so that it can practically be arranged at any free space on a folder-gluer. Besides, owing to its linking mode, its position can be adjusted according to the length of the flaps of the box blanks to fold. It is even possible, to position two folding devices so that they fold two flaps having transversely aligned creasing lines, but the lengths of which being different, by simply varying the distance h between the axis of the shaft 5 of the folding arms 6 and the plane P of the travelling path of the box blanks (Figs. 4 and 5), by sliding the housing 1 with respect to the linking plate T1 and by clamping the screw cradles 12 when the required distance h is obtained. A chart showing the value of h in accordance with the length of the flaps of the blanks can be drawn up for the operator.
By way of example, Figs. 4 and 5 show the relative positions of the axis of the shaft 5 of the folding arms 6 for lengths of flaps of box blanks of 20 to 25 mm, respectively 71 to 100 mm, with folding arms 6 of 100 mm radius.
Another possibility of the device according to the present invention is to use the folding arms 6 for holding the transverse creasing line around which the flap is folded from inside the fold. In fact, if the creasing line, during the folding operation and under the action of the force exerted on the folding flap from outside the fold, takes a convex shape inside the fold, the folding of the flap is no more possible. This risk is eliminated if the creasing line is held at the beginning of the folding operation. This is possible with the device according to the'present invention since there's nothing to prevent positioning of this device above the plane P of the path of the box blanks.
1. Device for folding flaps of box blanks having transverse creasing lines to the travelling direction of the blanks, for folder- gluer, comprising a rotary member around a transverse axis to the said travelling direction, provided with at least one folding arm (6), characterized in that it comprises removable linking means (11-13 ) to a support (10) secured to the frame (B) of the folder-guler, adjusting means ( 7, 8, 12, 13 ) of the position of the said folding arm or arms (6) with respect to the said support (10), a motor (2) for driving the said rotary member and, synchronization means of the said motor (2) comprising, on the one hand, an encoder (16) in desmodromic connection with a drive mechanism (9) of the box blanks and, on the other hand, a detector (14) of the passage at a reference position of the box blanks on the folder-gluer.
2. Device as claimed in claim 1, wherein the said adjusting means of the position of the said folding arm or arms (6) have two degrees of mobility, one of which being given by a support slide (10) transverse to the travelling direction of the said blanks with which a member (13) of the said removable linking means is engaged, and the other being given by a slide (7, 8) with which another member (12) of said linking means is engaged.
|Indian Patent Application Number||2241/DEL/2005|
|PG Journal Number||22/2010|
|Date of Filing||22-Aug-2005|
|Name of Patentee||BOBST S.A.|
|Applicant Address||CASE POSTALE CH-1001 LAUSANNE SWITZERLAND.|
|PCT International Classification Number||B31B 1/36|
|PCT International Application Number||N/A|
|PCT International Filing date|