Patent Publication Number: US-6659928-B2

Title: Device for removing flat articles

Description:
FIELD OF THE INVENTION 
     The invention relates to a device for removing flat articles, in particular blanks of collapsed boxes from a delivery station and for transferring these to a receiving station which has a transport device thereat to further transport the articles and to the provision of plural suction arms on a rotor which move through a closed cycloidal path, each having at least one suction device. The cycloidal path has plural tips and curved segments lying therebetween. The delivery station and the receiving station are each arranged at one tip of the cycloidal path. 
     BACKGROUND OF THE INVENTION 
     A device of this type is known from the DE 40 29 520. It is used to remove packaging blanks one by one from a magazine and to insert the blanks into compartments on a conveyor belt. The blanks are, during this insertion, pressed by means of a cam controlled mechanism and through a radial movement of the suction arms away from the rotor into the compartments and are thereat reshaped. 
     The known device has the disadvantage that the control mechanism is technically relatively expensive. 
     SUMMARY OF THE INVENTION 
     The basic purpose of the invention is therefore to provide a device of the above-described type, however, without a control mechanism. More specifically, a device is provided for removing flat articles, in particular blanks of collapsed boxes from a delivery station and for transferring them to a receiving station which has a transport device thereat. Plural suction arms each with suction devices thereon are provided, which suction arms move through a self-contained cycloidal path. The cycloidal path has several tips and curved segments lying therebetween. The delivery station and the receiving station are each arranged at a tip of the cycloidal path. A rotor is provided for moving the suction arms. 
     A sun and planet gear is provided on the rotor, which sun and planet gear delineates the cycloidal path, and the suction devices are aligned parallel to one another and preferably to the transport direction of the transport device. 
     The device of the invention has the advantage that it functions technically in a simple manner and without a control mechanism. The sun and planet gear is a common gear arrangement and actually produces the cycloidal path. The suction devices are aligned parallel to one another and remain always in this direction during their rotation. Thus, their connection to the sun and planet gear arrangement is also realizable in a simple manner. The suction devices are guided by the cycloidal path to an article, are then moved with the article to the delivery station, and are finally again placed on a following article. 
     An optimum time use of the device is achieved when three or four suction arms and pairs of suction fingers are provided on each suction arm. When an article is gripped by a pair of suction arms, then its removal and its forward movement are safer than if it were supposed to be moved merely by one single suction arm. The same purpose is also served by several suction devices on one suction arm. 
     When the rotor is continuously driven, then a particularly high article transfer rate is achieved since a standstill of the rotor is avoided. The movement of the rotor can thereby be slowed down by means of a servo technique at the tips of the cycloidal path, which tips are relevant for handling of the articles, in order to in this manner make the handling yet more reliable. 
     Flat collapsed-box blanks can be taken out of a magazine in order to erect these then along the cycloidal path on a guideway. The blanks are for this purpose moved with a prefolded edge along the guideway. The guideway is adapted to the cycloidal path in such a manner that when the blanks are moved along the cycloidal path, and the spacing between the guideway and the blank is reduced, the blank will be compressed in this manner to thereby erect the collapsed box. The erected box is subsequently delivered to the transport device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in greater detail hereinafter in connection with one exemplary embodiment and the drawings, in which: 
     FIG. 1 is a side view of a planetary gearing on a rotor, whereby three suction arms are each connected to one planet in order to move along a cycloidal path so that a blank for a collapsed box is taken out of a magazine, is erected at a guideway, and is presented at a delivery station to a transport device; 
     FIG. 2 is a cross-sectional illustration of the subject matter of FIG. 1; and 
     FIG. 3 is a cross section taken along the line B—B of FIG.  2 . 
    
    
     DETAILED DESCRIPTION 
     The device houses a sun and planet gear arrangement  1 , which describes a four-arc cycloidal path Z, and further, superposed gear steps  2 ,  3 , which cause a total translation of 1:1 from the frame  4  to the suction arms  5  so that these delineate on the one hand a cycloidal path Z, however, at the same time remain always parallel to a straight line in the frame  4 . 
     The sun and planet gear arrangement  1  consists of a rotor  6  which is fixedly connected to a drive shaft  7  supported on the frame  4 . Three planets  8  are provided on the rotor  6 , which planets consist of a hollow shaft  9 , a spur gear  10  and a crank  11 . The spur gear  10  and the crank  11  are fixedly connected to the hollow shaft  9 . Shafts  12  are supported in the planets  8 . Suction arms  13  with suction devices  14  are provided on the shafts  12 . 
     A translation from the spur gear  9  to the frame-fixed spur gear  15  with i=4 is used for the creation of the four-arc cycloids, an intermediate gear  16  being supported on the rotor  6 . The radius F of the planet has a relationship of approximately 1:3 with respect to the radius E of the rotor. 
     The gear steps  2  and  3  are superposed over the sun and planet gear  1  in order to achieve the parallelism of the suction device  14  and to the frame  4 . The gear step  3  consists of a rotor  17 , which is supported eccentrically with respect to the drive shaft  7  in the frame  4 , a shaft  19 , which is supported coaxially in the hollow shaft  9 , and a crank  18 , which is fixedly connected to the shaft  19 . In order to achieve a translation of 1:1 from the frame  4  to the shaft  19 , the eccentricity G must correspond with the crank radius H. The function thus corresponds to “half” of a Schmidt coupling. The gear step  2  consists of a spur gear  20 , which is fixedly connected to the shaft  19 , a further spur gear  22 , which is fixedly connected to the shaft  12 , and an intermediate gear  21 , which is supported on the crank  11 . The number of teeth of the spur gears  20  and  22  must hereby be identical. 
     When the suction arm  13 , which includes a pair of suction fingers  27  on which is provided the suction devices  14 , moves into the area of the tip A of the cycloidal path Z, a blank  34  is sucked from the magazine  23 , and when the suction arm  13  leaves the tip A, this blank  34  is held by the suction devices  14  and is pulled out of the magazine  23  past the holding noses  24 . When moving through the arc from tip A to tip B, the edge  35  of the blanks  34  remote from the sun and planet gear  1 , is guided along a guideway  25  so that the flat blank  34  is erected into a sleeve. Prior to the suction arm  5  reaching tip B, the blank  34  is transferred to a moving transport device  26 . The vacuum of the individual suction arms  5  are controlled mechanically by a circular-arc segment inserted into the spur gear  15 . The air is sucked off through suction passageways  28 ,  29 ,  30  and a line  31  from the suction devices  14  so that the blank  34  will be adhered to the suction devices  14  by the suction force. 
     This system is particularly advantageous during the suction and erection since the blank  34  can at any time be held both parallel to the magazine  23  and also to the transport device  26  so that wider blanks  34  can also be easily processed. In addition it is advantageous that during the removal from the magazine  23  a movement in direction of the magazine  23  takes place almost exclusively, whereas the blank  34  has during the transfer to the transport device  26  already an inertial movement component in transport direction. 
     A further advantage is that any desired number of planets  8  with suction arms  13  can be fastened on the rotor  6 . Thus it is, for example, possible when the number of pairs of suction arms  27  is increased from three to four to achieve a 33 percent increase in performance, whereas the driving speed and thus the suction, erection and transfer time remains the same as in the case of three pairs of suction arms  27 . 
     List of Reference Numerals 
     A,B,C,D Tips 
     E,F radius 
     G eccentricity 
     H crank radius 
     Z cycloidal path 
       1  sun and planet gear 
       2 , 3  gear step 
       4  frame 
       5  suction arm 
       6  rotor 
       7  drive shaft 
       8  planet 
       9  hollow shaft 
       10  spur gear 
       11  crank 
       12  shaft 
       13  suction arm 
       14  suction device 
       15  spur gear 
       16  intermediate gear 
       17  rotor 
       18  crank 
       19  shaft 
       20  spur gear 
       21  intermediate gear 
       22  spur gear 
       23  magazine 
       24  holding noses 
       25  guideway 
       26  transport device 
       27  pair of suction fingers 
       28 , 29 , 30  suction passageway 
       31  line 
       34  blank 
       35  edge 
       36  delivery station 
       37  receiving station 
       38  transport device