Abstract:
A tuft picker device for a brush making machine has a bristle magazine for holding a supply of loose bristles and a tuft picker having a tuft picking notch being movable past an open side of the bristle magazine in a working stroke. A shield member is adapted to be shifted across the tuft picker notch to change the effective depth thereof. The shield member can be adjusted by an adjusting device in each working stroke in order to vary the effective depth of the tuft picking notch from one working stroke to the next to change the size of a tuft engaged in the notch.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a tuft picking device for a brush making machine. 
       BACKGROUND OF THE INVENTION 
       [0002]    Tuft pickers serve to remove individual tufts of bristles from a bristle magazine in succession in order to feed them to a brush making machine. The tuft picker essentially is a slider which reciprocates in a sliding motion at an open side of the bristle magazine and has a tuft picking notch in which the bristles forming the tuft will collect during the sliding motion past the bristle magazine. The tuft picker transports each separated tuft of bristles to a processing station, for example a tufting tool, and is then moved back to the bristle magazine for separating the next tuft of bristles. With each working stroke of the tuft picker, a tuft of bristles is separated in this way. 
         [0003]    The profile of the tuft picking notch dictates the quantity of the bristles that are separated in each working stroke of the tuft picker. In order that a single tuft picker device can be used for separating tufts having different quantities of bristles, the effective depth of the tuft picking notch can be varied by laterally covering part of the profile with a shield member. Rather than the bottom of the tuft picking notch, it is then the shield member that defines the depth up to which the bristles can penetrate into this notch. A tuft picking device including a tuft picking notch having an adjustable effective depth is disclosed, e.g., in DE 40 40 297 C2. A device of this type is suitable for separating bristle tufts of different cross-sections for different brushes. 
         [0004]    A knot picking machine is disclosed in U.S. Pat. No. 1,641,686 having a member is provided on the tuft picker, which can be moved transversely to the slot so as to regulate the effective area of the slot for receiving bristles. The member is substantially semi-circular and is fixedly mounted with a screw. 
         [0005]    In connection with modern brushes, in particular toothbrushes, it has been desirable to have bristle tufts of different cross-sectional shapes and sizes that are arranged next to each other in a bristle field. Brushes of this kind are complicated to produce since the high-speed, efficiently operating brush making machines available can not be used for making them. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention provides a tuft picking device that is capable of varying the effective depth of the tuft picking notch in each working stroke while keeping abreast of modern high-speed brush making machines. The tuft picking device according to the invention for a brush making machine has a bristle magazine for holding a supply of loose bristles, a tuft picker having a tuft picking notch being movable past an open side of the bristle magazine in a working stroke. At least one shield member is adapted to be shifted across the profile of the tuft picking notch to thereby change the effective depth thereof. The shield member is displaced by way of a constrained guidance using an adjusting device. Actuating drives are available which can perform the required small adjusting stroke rapidly, precisely and reproducibly. An important factor here is a rigid coupling between the shield member and the actuating drive. 
         [0007]    It was found to be of advantage to use a crank drive including a rotary drive that is fixed to the machine frame and has a servomotor and includes a crank arm. The crank arm is articulated with a connecting rod which in turn is articulated with a stirrup that is adapted to be shifted in translation on the machine frame. Through the stirrup, the adjusting stroke is rigidly transmitted to the shield member. 
         [0008]    The tuft picker may be curved along a circular arc and be adapted to be pivoted about a fixed axis in a conventional fashion. The shield member then is a rigid rail which is curved in the shape of a circular arc and is engaged by the adjusting device. Alternatively, the actuating drive engages a curved rigid guide which is radially displaceable in relation to the axis and has a cam follower guided in a constrained fashion therein which actuates the shield member. 
         [0009]    In another aspect of the invention, the actuating drive comprises a follower member pivotally mounted on the tuft picker itself. The follower member engages with a guide having a guide surface which determines the deflection or pivot angle of the follower. The follower in turn is coupled to a lever mounted on the tuft picker, a portion of the lever defining the shield member. Rotation of the follower member then causes rotation of the lever, which in turn moves the shield member across the notch to vary the effective depth of the notch. This embodiment has the advantage that the actuating drive components are integrated with or into the tuft picker itself and no separate mounting means are necessary to fix the actuating drive to the machine frame. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Further features and advantages of the invention will be apparent from the following description of several embodiments with reference to the accompanying drawings in which: 
           [0011]      FIG. 1  shows a diagrammatic top view of a tuft picking device having an actuating drive for controlling a shield rail which has the shape of a circular arc and is used for varying the effective depth of a tuft picking notch in a tuft picker. 
           [0012]      FIG. 2  shows a view of a detail from  FIG. 1  on an enlarged scale. 
           [0013]      FIG. 3  shows a second embodiment of the tuft picking device comprising a lever mounted on the tuft picker. 
           [0014]      FIG. 4  shows a top view of a third embodiment of the tuft picking device by which the shield member is adjusted to a follower member engaging a guide. 
           [0015]      FIG. 5  shows a perspective view of the embodiment of  FIG. 4 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    The embodiment of the tuft picking device as shown in  FIG. 1  has a tuft picker  10  that is curved in the shape of a circular arc and can be pivoted about an axis A which is fixed in relation to the machine frame of a brush making machine. The tuft picker  10  has in its peripheral surface a tuft picking notch  12 , which is illustrated greatly enlarged in  FIG. 2 . The peripheral surface of the tuft picker  10  is in contact with an open side of a bristle magazine  14  which has parallel bristles, cut to length, loosely held therein. The tuft picker  10  can be pivoted about the axis A by in working stroke in which the tuft picking notch  12  is moved over the open side of the bristle magazine  14  so that the tuft picking notch fills with bristles from the bristle magazine  14 . During the return movement of the tuft picker  10 , the bristles that have been removed are held in place in the notch  12  by a screen  16  which is in contact with the periphery of the tuft picker  10 .  FIG. 1  shows the tuft picker  10  in a delivery position in which the separated tuft of bristles is transferred from the notch  12  to a workstation of a brush making machine. 
         [0017]    For varying the effective depth of the tuft picking notch  12 , a shield or covering member in the form of a rigid rail  18  is provided which is curved in the shape of a circular arc. The rail  18  is connected to a rigid stirrup which consists of a pair of parallel bars  20 ,  22  and a web  24  connecting them. The stirrup, and the rail  18  along with it, are articulatedly connected via the web  24  to a connecting rod  26  which in turn is articulatedly connected to a crank arm  28  of a rotary drive  30 . The rotary drive  30  is mounted on the machine frame of the brush making machine. As indicated by a double arrow in  FIG. 1 , the bars  20 ,  22  of the rigid stirrup are mounted to be displaceable in the radial direction in relation to the axis A. Together with the crank drive made up of the crank arm  28  and the connecting rod  26 , the rotary drive  30  forms an actuating drive for moving the rail  18  via the rigid stirrup which is formed by the bars  20 ,  22  and the web  24 . This actuating drive, the rotary drive of which is preferably constituted by a servomotor, is capable of displacing the rigid rail  18  in relation to the tuft picker  10 , as indicated by a double arrow in  FIG. 2 , and of doing so very rapidly, very precisely and in a well reproducible manner. This displacement causes the rail  18  to slide transversely across the profile of the tuft picking notch  12  in order to change the effective depth thereof.  FIG. 2  shows the rail  18  in a middle position, in which the overall depth of the notch  12  is approximately reduced by half. 
         [0018]    In the tuft picking device according to  FIG. 3 , the tuft picker  10   a  cooperates with a shield member  18   a  that is formed by one end of a two-armed lever  19  which is mounted at the tuft picker  10   a  for pivoting about a pin  21 . The opposite end of the two-armed lever  19  carries a cam follower in the form of a roller  32 . The roller  32  is guided in a guide  34  which is curved so as to correspond to the shape of the tuft picker  10   a  and is mounted on the machine frame so as to be radially displaceable in relation to the axis A of the tuft picker  10   a.  The guide  34  is coupled to an actuating drive by means of rigid bars  36 ,  38 ; the actuating drive may be implemented in the same way as in the embodiments described above. 
         [0019]    As the tuft picker  10   a  performs a pivoting movement, the roller  32  is guided in a constrained fashion in the guide  34 . The radius to which the guide  34  is set in relation to the axis A dictates the pivoting position of the two-armed lever  19 . The pivoting position of the two-armed lever  19  in turn determines the level of the shield member  18   a  relative to the bottom of the profile of the tuft picking notch  12   a.  Since the radial adjustment of the guide  34  causes a change in the pivoting position of the lever  19  and thus in the position of the shield member  18   a,  as a result the effective depth of the tuft picking notch  12   b  can be varied. 
         [0020]      FIGS. 4 and 5  illustrate a further embodiment of the present invention by which the actuating drive components are provided on or integrated with the structure of the tuft picker itself. The tuft picker  10   b  in this embodiment is formed as a circular arc segment which pivots about an axis A. The tuft picker  10   b  is supported by a carrier  45  which is coupled to the shaft  46 . The center line of the shaft  46  defines the pivot axis A of the tuft picker. In this embodiment, the shield member  18   b  is formed as a first portion  19 ′ of a lever  19  mounted through a pivot pin  21  on the tuft picker  10   b.  A second portion  19 ″ of the lever  19  is coupled to a follower member for adjusting the pivot angle of the lever  19  and therefore the relative position of the shield member  18   b  with respect to the notch  12   b.    
         [0021]    The follower member, as part of the actuating drive, comprises a first pivot arm  40  and a second pivot arm  44  mounted on a shaft  42 . The shaft  42  is pivotally mounted on the carrier  45  and the center line of the shaft  42  defines the second axis B. As best seen in  FIG. 4 , the second pivot arm  44  engages with the second portion  19 ″ of the lever  19  through a slide contact connection. A pin  41  on the second pivot arm  44  engages with a slot  31  on the second portion of the lever  19  so as to transmit angular motion. 
         [0022]    The actuating drive further comprises a guide member  50  mounted on the shaft  46  so as to be slidable in axial direction. As indicated with the double arrow in  FIG. 5 , the guide member  50  can be moved up and down along the shaft  46 . The axial position of the guide member  50  is adjusted by a crank drive mechanism. The crank drive includes a rotary drive  30 , for example a servo drive, connected to a crank arm  28 . The crank arm  28  is connected to the guide member  50 , such that a rotational position of the rotary drive  30  precisely determines the axial position of the guide member  50  on the shaft  46 . 
         [0023]    An outer peripheral surface  52  of the guide member  50  is provided with an inclination in the axial direction of the axis A, which can best be seen in  FIG. 5 . In the present embodiment, the radial dimension of the surface  52  decreases from top to bottom as shown in the embodiment of  FIG. 5 . As can also be seen in the figures, the inclined surface  52  has an angular extension to account for the angular range of motion of the tuft picker. 
         [0024]    A roller  48  is attached to the first pivot arm  40  so as to engage the inclined surface  52 . Depending on the axial position of the guide member  50 , the roller  48  engages a different portion of the inclined surface  52 . As a result, the first pivot arm  40  is deflected by a certain pivot angle depending on the position at which the roller  48  engages the inclined surface  52 . In the condition shown in  FIG. 5 , the roller engages a lower region of the inclined surface  52 , such that the deflection or pivot angle of the first pivot arm  40  is small. In the condition shown in  FIG. 4 , the guide member  50  has been lowered toward the tuft picker  10   b  and the roller  48  engages the top or higher region of the inclined surface  52 . The pivot angle of the first pivot arm  40  is correspondingly larger. 
         [0025]    As can be taken from the above, a rapid and reliable adjustment stroke can be applied to the shield member. By controlling the rotary drive  30 , for example with a step motor, the guide member with its inclined surface  52  can be precisely set in axial direction. Consequently, the pivot angle of the follower member is reliably set along with the pivot angle of the lever. As a result, the relative position of the shield member with respect to the notch is defined.