Abstract:
The invention relates to an apparatus and a method for automatically closing envelopes. The apparatus contains a transport means for moving the envelopes in a transport direction, and a means for automatically folding back and closing an envelope flap. To enable accurate and reliable closing even of tightly filled envelopes even in a continuous operation duty, the means for automatically folding back and closing the envelope flap comprises several rotors which are rotatable in the transport direction of the envelopes and are movable, by means of a drive, in a manner which is transverse to the transport direction of the envelopes.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of copending International Application No. PCT/EP2005/001615, filed Feb. 17, 2005, which designated the United States, and was not published in English and is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to an apparatus and a method for automatically closing envelopes. 
     2. Description of Prior Art 
     One has already known enveloping means for filling and closing envelope automatically, or by machine, wherein the envelope flaps of the envelopes conveyed by a transport means are folded back by a stationary buffer plate and are subsequently pressed on by a press-on device. However, with this device, no parallel closing of the flap is performed, which may result, particularly with envelopes filled to a certain thickness, in that the envelope flaps are closed in an oblique manner. 
     To solve this problem, closing drums have already been employed which are journalled around an axis extending in parallel with the transport direction of the envelopes, and are moved in a manner which is transverse to the envelope for folding back the envelope flap. However, it is required, to this end, to interrupt the transport movement of the envelopes. Thereby, the clock performance is limited, particularly with high-performance enveloping equipment. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to provide an apparatus and a method of the type mentioned at the outset which enable accurate and reliable closing, in a continuous operation duty, even of envelopes filled to a certain thickness. 
     In accordance with a first aspect, the invention provides an apparatus for automatically closing envelopes with a transporter for moving the envelopes in a transport direction, and a folder for automatically folding back and closing an envelope flap, characterized in that the folder for automatically folding back and closing the envelope flap contains several rotors which are rotatable in the transport direction of the envelope and are movable, by a drive, in a manner which is transverse to the transport direction of the envelopes. 
     In accordance with a second aspect, the invention provides a method for automatically closing envelopes, wherein the envelopes are transported, by a transporter, in a transport direction past a folder for automatically folding back and closing an envelope flap, characterized in that during the transport of the envelope, the envelope flap is folded back and closed, along its entire length, by several rotors which are rotatable in the transport direction and are moved, in a manner which is transverse to the transport direction, across the envelope flap, which has previously been lifted up. 
     The inventive apparatus is characterized in that the means for folding back and closing the envelope flap in an automated manner contains several moveable rotors that are rotatable in the transport direction of the envelope and are moveable, by means of a drive, in a manner which is transverse to the transport direction of the envelopes. 
     A crucial advantage of the inventive configuration is that envelopes filled to have both small and large thicknesses may be closed by machine without delay and without interrupting the transport. Above all, the inventive apparatus solves the problem of the envelope height and of the large filling height in the case of thick filling. Without stopping, during transport, the envelope flap, which has been moistened and, prior to that, lifted up, is folded back, and the envelope is closed. Thus, no stopping location, no braking and no renewed accelerating are required. Thus, automated closing of envelopes may also be effected at high speeds. 
     In a particularly expedient embodiment of the invention, the rotors are configured in the form of drums which are journalled on axes which extend in a manner which is transverse to the transport direction of the envelopes. At their ends which point to the envelope flap, the drums are rounded in an advantageous manner, or have an inclination. Thus, it is possible to drive the rotor onto the envelope flap in a trouble-free manner. 
     In accordance with a further advantageous implementation, the rotors comprise a front area having a low frictional constant, and a back area having a high frictional constant. Driving the rotors onto the envelope flap may thus be effected through the areas having low frictional constants, whereby the rotors may take on the transport speed of the envelope. Through areas having high frictional constants, which subsequently engage the envelope flap, the envelope flap is pushed across the envelope to the flap break in a uniform and parallel manner, and is closed. In this manner, a force is exerted on the envelope flap which acts in the closing direction and which serves to not only fully close the envelope flap but also to insert any sheets which have not been fully inserted into the envelope, right down to the bottom of the envelope. 
     In a configuration which is simple in construction and low in cost, the different frictional constants of the rotors may be achieved in that the rotor consists of plastic and exhibits, at its back area, external frictional elements, e.g. in the form of rubber rings or the like. 
     In order to enable the rotors to be driven onto the envelope flap in a manner which is as free from trouble as possible, and in order to prevent the envelopes from slorocker down, the carrier has arranged thereon a spacer which is embodied, for example, as a distance drum, and by means of which the rotors are kept at a predefined distance from the base. 
     The inventive method is characterized in that, during the transport of the envelopes, the envelope flap is folded back and closed, along its entire length, by several rotors which are rotatable in the transport direction and are moved, in a manner transverse to the transport direction, across the envelope flap, which has previously been lifted up. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects and features of the present invention will become clear from the following description taken in conjunction with the accompanying drawing, in which: 
         FIG. 1  is an inventive apparatus for automatically closing envelopes, in a top view, and 
         FIG. 2  is the apparatus depicted in  FIG. 1  for automatically closing envelopes, in a side view. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The apparatus for automatically closing envelopes which has been schematically represented in  FIGS. 1 and 2  contains a transport means  1  which is embodied, for example, as a conveyer belt, and by means of which several envelopes  2  which previously have been filled with the respective content in a filling station are successively conveyed, in their longitudinal direction, in a transport direction characterized by arrow  4  in  FIG. 1  on a base  3  shown in  FIG. 2 . A means  5  for automatically folding back and closing an envelope flap  6  on the previously filled envelopes  2  is arranged on base  3  in parallel with transport means  1 . 
     Means  5  for automatically folding back and closing the envelope flap  6  contains a carrier  7  which is movable in a manner which is transverse to the transport direction of the envelopes  2  and which has several rotors  8  arranged thereon which are mutually successive in the transport direction of the envelopes  2 . As may be seen from  FIG. 2 , carrier  7  contains a rail-shaped front portion  9 , which extends in parallel with the transport direction of the envelopes  2 , and two side portions  10  which are at right angles in relation to part  9  and are interconnected in the back area by a connecting rod  11 . By means of two spaced-apart rockers  12 , carrier  7  is articulated so as to swivel around an upper axis of rotation  14  extending between two lateral supports  13 . The two lateral supports  13  are attached to base  3 . 
     In the embodiment shown, rotors  8  are configured in the form of drums which are rounded in the shape of a hemisphere at their front ends facing envelope flap  6 . 
     Rotors  8  are journalled on axes  15  which extend transverse to the transport direction of envelopes  2 . The axes  15  are mounted, in a manner which is transverse to the transport direction of envelopes  2  and such that they protrude forward toward envelope flap  6 , on front part  9  of carrier  7  which extends in parallel with transport means  1 . Rotors  8  comprise a front area  16  having a low frictional constant, and a back area  17  having a high frictional constant. To this end, rotor  8  expediently consists of a plastic (e.g. POM) having a low coefficient of friction. In the back area of rotors  8 , revolving ring grooves  18  for one or several friction elements  19  consisting of rubber or the like are introduced in the form of O-rings. Thereby, rotor  8  has a higher frictional constant in this area. By selecting the number of frictional elements  19  accordingly, the frictional constant at the respective rotors  8  may be altered. A distance drum  20  which has a larger external diameter than rotors  8  and bears on base  3  is mounted on the last axis  15  as seen in the transport direction. This distance drum  20  guarantees that rotors  8  have a predefined distance from base  3 , as is shown in  FIG. 2 . 
     In accordance with  FIG. 2 , the two mutually spaced-apart rockers  12  are articulated on connecting rod  11  with their lower ends, and on rotation axis  14  with their upper ends. On the two rockers  12 , a drive  21  configured, for example, as a lifting magnet, engages between the upper and lower ends, it being possible, by means of said drive  21 , to move carrier  7  with the rotors  8  arranged thereon, for folding back envelope flap  6 , in a manner which is transverse to the transport direction of envelopes  2  between a back initial position shown in  FIG. 1  and a front closing position indicated by only one rotor. A spring arrangement  22 , by means of which the distance drum  20  arranged on the carrier  7  is pressed onto the base acts on the ends of the two lateral parts  10 , the ends projecting backward opposite connecting rod  11 . In addition, front and back end-position dampers  23  and  24  are provided by means of which the formation of oscillations while swiveling the carrier  7  between the initial position and the closing position is prevented. 
     The above-described apparatus operates as follows: 
     The envelope  2  previously filled in a filling station is transported, by transport means  1 , in the longitudinal direction along means  5  for automatically folding back the envelope flap  6 . By means of a stationary folder  25  arranged upstream from means  5  in the transport direction, the envelope flap  6 , facing the rotors  8 , of envelope  2  is slightly lifted beforehand. As soon as envelope  2  has reached a position, shown in  FIG. 1 , wherein envelope flap  6  may come into contact, along its entire length, with rotors  8 , the two drives  21  are activated such that carrier  7  passes from its initial backward position to the front; closing position. Control of the two drives  21  is effected as a function of a sensor  26  connected upstream from means  5  which detects the arrival of an envelope  2  to be closed, and initiates actuation of the two drives  21  after a predetermined lapse of time. However, sensor  26  may also be arranged such that control is effected at the same time as the detection of the leading edge of envelope  2 . 
     When carrier  7  is swiveled into the closing position, rotors  8  initially come to lie, by means of their area  16  with the low frictional constant, on envelope flap  6 , whereby rotors  8  are guided onto envelope  2  and take on its transport speed. After being driven, for a short time, onto envelope flap  6 , areas  17  having the high frictional constant, start to operate and exert, onto envelope flap  6 , a force in the closing direction which also causes any content which may still be projecting to be pressed into the envelope. Envelope flap  6  is pushed, right up to the flap break, across envelope  2  in a uniform and parallel manner, and is closed. The rail-shaped front part  9  of carrier  7  having the rotors  8  arranged thereon is longer than envelope  2 , so that during swiveling of carrier  7  into the closing position, the entire envelope flap  6  is constantly in contact with rotors  8  even while envelope  2  is transported further. The distance drum  20  ensures that the rotors  8  do not slow down the envelope  2  while envelope  2  is introduced into means  5 . Once envelope  2  has left distance drum  20 , carrier  7  returns to its initial position. 
     While this invention has been described in terms of several preferred embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.