Abstract:
A web wrap apparatus is provided and has a brake device that exerts pressure on a roll of a web material. In order to exert pressure even after the web material is cut, the brake device is locked by a retainer once the web is separated and is released by a feeder, when moving from a home position to a web feed position.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to a web wrap apparatus with a brake device acted upon by a web pulled by an article being wrapped, and having a feeder to transport the web. 
       BACKGROUND OF THE INVENTION 
       [0002]    EP 2 044 830 A1 discloses a wrapping means tensioning device having a control arm and a brake arm, both being pivotally connected to one another and pivoting as a unit about an axis. The brake arm presses on a net roll to achieve a certain tension in the net during the wrapping process. The free end of the control arm is applied by the net and is deflected by it even more as the tension in the net increases. As a result, the pressing force onto the web roll will disappear, once the net is cut. 
         [0003]    The problem this invention is based on is seen in the fact, that the net roll continues with its rotation even after the net is cut, which results in net being wound off the roll and being apt to create a net curl. 
       SUMMARY OF THE INVENTION 
       [0004]    According to the invention the brake arm rests against the roll of web, even when the latter is cut and the brake device is no longer activated by the web. The force applied by the brake device does not necessarily need to remain at the highest level, but be at least sufficient to hinder the web roll from further rolling. The retainer may be a mechanical lock as well as a powered device like a motor, a solenoid activated clutch, lock, etc. The feeder may be of any type, like a duckbill, feed roller(s), feeder comb, etc. The movement of the feeder to start the feeding process will be used to unlock the brake device and release the brake. In case the feeder has a built-in reservoir for the web, the brake may open later; the brake may open earlier as well, provided the web roll has stopped rolling. 
         [0005]    If the retainer is in the form of a multi-position ratchet, one part of it being located on the brake device and one part on the feeder, the brake device may be locked not just in one position, but at the position of maximum brake force, which has been achieved by the brake device. The ratchet may be a toothed rod, arc, etc. and a small driver entering the teeth. 
         [0006]    In order to release the brake device, a lever, linkage, Bowden cable or the like may be used, which is activated by a movement of the feeder. A spring—mechanical or pneumatic—may force the lever into the locked position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings wherein: 
           [0008]      FIG. 1  is a round baler in schematic side view provided with a web wrap apparatus; 
           [0009]      FIG. 2  is the web wrap apparatus of  FIG. 1  depicted in a waiting position; 
           [0010]      FIG. 3  is the web wrap apparatus of  FIG. 1  depicted in a waiting position; 
           [0011]      FIG. 4  is the web wrap apparatus of  FIG. 1  depicted in a feeding operation on the way back to the waiting position; and 
           [0012]      FIG. 5  is the web wrap apparatus of  FIG. 1  depicted in a partly retracted position acting on a lever. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]      FIG. 1  shows around baler  10 , which has a chassis  12 , a pick-up  14 , a bale chamber  16 , a web wrap apparatus  18 , an axle with wheels  20 , a tongue  22  and baling elements  24 . 
         [0014]    The round baler  10  shown is of an ordinary fixed chamber design, but could also be a variable chamber design. 
         [0015]    The chassis  12  rests on the axle with the wheels  20 , carries the pick-up  14  and can be connected to a tractor or the like by way of the tongue  22 . The chassis  12  has one or multiple part side walls  26 , which are spaced apart from one another to receive between them the bale chamber  16 , all or part of the web wrap apparatus  18  and the baling elements  24 . 
         [0016]    The pick-up  14  picks up crop from the ground and delivers it to the bale chamber  16  through a crop inlet  28  between the baling elements  24 . 
         [0017]    The bale chamber  16  is covered substantially by the baling elements  24  on the circumference and by the side walls  26  on the face sides. Beside the crop inlet  28  a gap  30  is provided between the baling elements  24 , through which web  32  may be fed into the bale chamber  16 . The bale chamber  16  serves to form a cylindrical bale of hay, straw or the like, which will be covered by the web  32  of plastic, net paper or the like. The baling elements  24  in this embodiment are in the form of steel rolls rotatably received in the sidewalls  26  and extending perpendicular to them. These baling elements  24  are arranged substantially on a circle. 
         [0018]    The web wrap apparatus  18  is visible in more detail in  FIG. 2  and contains among other things a housing  34 , a motion element  36 , a brake device  38 , a feeder  40  and a separator and an actuating mechanism (not shown). The latter are described in more detail in European Patent Appl. No. 09155481.6 filed on 18 Mar. 2009. 
         [0019]    The housing  34  is located in the front upper part of the round baler  10  between or substantially between the side walls  26  and has a rear wall  46  and a left and a right wall  48  connected to one another and suitable to be connected to the side walls  26 . Depending on the width of the web  32 , the housing  34  and the entire web wrap apparatus  18  may extend beyond the side walls  26 . The rear wall  46  may be of a material, or may have a layer, which creates a certain friction, which will have an influence on the rolling resistance of a roll  50  of the web  32 . The housing  34  may be used to attach all components and parts of the web wrap apparatus  18  to it to form an autonomous unit. The right and left walls  48  extend to the rear towards the bale chamber  16  as needed to take up some of the parts described later. 
         [0020]    The motion element  36  is formed by a roll  52 , preferably rubber coated, which is journalled rotatably about a horizontal axis in the side walls  48  and which is located such that the roll  50  of the web  32  can rest on it. As is known in the art, but not shown here, the roll  52  is connected via a chain drive and a free-wheel to the baling elements  24  such that it must rotate slower than the baling elements  24 . 
         [0021]    The brake device  38  substantially has a control arm  58  and a brake arm  60  connected together on a shaft  62  to pivot about a horizontal axis of the latter. A gas spring (not shown) may be connected to the shaft  62  via an arm (not shown) to assist or resist the rotational movement of the shaft  62 . It is the purpose of the brake device  38  to exert a certain pressure onto the roll  50  of the web  32  to assure a sufficient tension in it, when it is wrapped onto a bale (not shown). The shaft  62  is located at about the same height as the roll  52  and at a certain distance to it forwardly. The control arm  58  extends underneath the roll  52  and from a location rearward of the roll  52  to the shaft  62  and ends at about the center of the roll  52 . The control arm  58  has an idler bar  68  or an angle extending parallel to the axis of the roll  52  between the side walls  48  of the web wrap apparatus  18 . The brake arm  60  extends from the shaft  62  to a location above a completely wrapped roll  50  of the web  32  and has a cross element  70  designed to push onto the circumferential surface of the roll  50 , thereby pressing the roll  50  against the rear wall  46  and creating the desired rolling resistance. As is apparent from the drawing, a downward, counter-clockwise movement of the control arm  58  will provoke a counter-clockwise movement of the brake arm  60  upon the roll  50  of the web  32 . 
         [0022]    The feeder  40  in this embodiment is formed as a so-called duckbill, which however is not mandatory; it could be any other moving part pulling the web  32  from the roll  50  and feeding it into the bale chamber  16  through the gap  30 . The feeder  40  is composed of struts  72  on each side holding between them a carrier  74  in the form of a mouthpiece at a lower end thereof, two vertically distant bearings  76 . The carrier  74  as such is known and has two opposite plates biased onto one another to clamp a piece of the web  32  and move it rearward. An upper link  82  and a lower link  84  forming part of a parallelogram linkage are connected with one end area to the bearings  76  and with their other end areas to the bearings  86  on the side walls  48  of the web wrap apparatus  18  being offset horizontally as well as vertically; lines through the bearings  76  at one end and the bearings  86  at the other end do not run parallel but divergently. The upper link  82  has an eye  88  on its upper side or a bore or the like useful to provide a connection to an actuator  110  such as an electric or hydraulic motor. An idler element  116  is connected to and connects the struts  72  on both sides. The idler element  116  assists in feeding the web  32  in a proper way into the carrier  74 . The idler element  116  may consist of a simple bar or shaft. 
         [0023]    The motor  110 , which may be actuated electrically, hydraulically or pneumatically is connected with one side to the side walls  48  of the web wrap apparatus  18  or any other stationary feature of the chassis  12  and with the other side to the eye  88  on the upper link  82 . 
         [0024]    As is best seen in  FIG. 3  a lever  118  is provided, with which an upper end area is journalled in a bearing  120  (see  FIG. 2 ) in the wall  48  and which in its lower end area has a longitudinal slot  122  extending substantially on a circle about the bearing  120 . Furthermore the lever  118  has a contact area  124  on the rear side and an aperture  126 . The contact area  124  may be an angle or flat steel welded to the lever  118  and extending perpendicular to it. The lever  118  extends substantially vertically. 
         [0025]    At the wall  48  a guide  128  is provided, which in a simple manner consists of a bolt, a bushing, a rod or the like, protruding through the slot  122  to limit the pivot movement of the lever  118  about the bearing  120 . 
         [0026]    A retainer  130  in the form of a ratchet is provided in an area, where the control  58  and the lever  118  make contact with one another. The retainer  130  has a first part  132  in the form of a toothed bar, cam or the like, wherein the teeth face towards the lever  118 . The teeth are oriented and slanted downwardly to provide a good grip. A second part  134  of the retainer  130  is provided at the end of the lever  118  and has the form of a tooth, which may enter the space between two teeth on the first part  132 . This second part  134  is oriented upwardly to engage securely in the first part  132 . 
         [0027]    Finally a spring  136  is installed between the aperture  126  and a location at the wall  48 . The spring  136 , which in this case is a coil tension spring, can be of any kind but needs to bias the lever  118  in a mating position of the first and the second part  132 ,  134 , respectively. 
         [0028]    While on either side one lever  118 , one retainer  130  and one spring  136  would be sufficient it would be beneficial to have such a set on both sides of the round baler  10 . 
         [0029]    Based on this structural description the function is described as follows starting from a state shown in  FIG. 2 , in which the web wrap apparatus  18  waits to be operated. In a state as shown in  FIG. 2 , the roll  50  with the web  32  is placed on the roll  52  and is secured in its position between the cross element  70  and the rear wall  46 . The feeder  40  is in a position remote from the gap  30 . The web  32  extends from the roll  50 , underneath the roll  52  over the idler bar  68 , through the carrier  74 , where it is clamped. 
         [0030]    As soon as a manual or electrical signal is given to the actuating motor  110  to initiate wrapping the web  32  around a bale, the motor  110  is extended, thereby moving the feeder  40  downward and towards the gap  30 . Once the carrier  74  protrudes the gap  30 , the web portion hanging down from the carrier  74  is caught by the rotating bale and pulled from the roll  50 . Tension is created in the web  32 , since the roll  50  experiences friction on the wall  46  and since the roll  52  is hindered from free movement.  FIG. 5  shows a situation, in which the motor  110  is retracted and thereby the feeder  40  is on its way back to a resting or home position. 
         [0031]      FIG. 3  shows a situation, in which both parts  132 ,  134  are in a positive locking condition, whereas the control arm  58  is in a low position, which corresponds to the lowest position reached in the preceding wrapping cycle. The struts  72  are distant from the contact area  124  of the lever  118 . Due to the connection between the control arm  58  and the brake arm  60 , pivoting about the shaft  62 , this location of the control arm  58  will exert considerable pressure on the web roll  50  through the contact with the cross member  70 . 
         [0032]      FIG. 2  shows the feeder  40  on its way to the gap  30  by pivoting about the bearings  86 . During this downward movement the upper end of the struts  72  will hit the lever  118  in the contact area  124  and will push the lever  118  forward. The clockwise movement will disconnect the two parts  132 ,  134  of the retainer  130  and the assembly of the control arm  58  and the brake arm  60  is free to pivot upwardly either by the inherent bending forces in the brake device  38  and/or by the gas spring acting between the shaft  62  and the brake arm  60 . The result is the position shown in  FIG. 2 . 
         [0033]      FIG. 4  shows a situation, in which the web  32  is pulled by the bale in the bale chamber  16  and due to the tension in the web  32  the idler bar  68  is pushed down. Since at the same time the feeder  40  returns to its home position, the retainer  130  is disconnected, which at that time is no problem, since the tension in the web  32  still endures. 
         [0034]    In  FIG. 5  the feeder  40  has almost passed the lever  118 , which then will again connect the two parts  132 ,  134  of the retainer  130  by virtue of the spring  136 . When the web  32  is separated by a separator (not shown), the retainer  130  is locked and remains locked, until the wrapping cycle starts from the beginning. 
         [0035]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.