Abstract:
A system for oscillating a roller driven by rolling contact with a moving substrate. An oscillating assembly comprises first and second opposed gudgeons rotatably mounted on a shaft, the gudgeons being connected by either a plurality of rods or the roller. An oscillation mechanism comprises a reduction transmission assembly having differently toothed input and output pulleys. A cam groove in an oscillation cam is engaged by one or more oscillation pin(s) connected to the gudgeons. An input drive pulley turns with the gudgeons, and an output pulley turns with the oscillation cam. An intermediate double-pulley has second and third pulleys on a common hub. First and second timing belts connect, respectively, the input pulley to the second hub pulley, and the third hub pulley to the output pulley. A currently preferred step-down ratio between the input pulley and the output pulley is about 391:1.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to apparatus for causing a rotating roller to oscillate axially, more particularly to such an apparatus wherein the roller is driven by rolling contact with a moving substrate, and most particularly to a system wherein the roller is a contact cleaning roller oscillated axially as it is rolled along a non-oscillating moving substrate surface to be cleaned by transfer of particles from the substrate to the contact cleaning roller. 
       BACKGROUND OF THE INVENTION 
       [0002]    U.S. Pat. No. 5,611,281 issued Mar. 18, 1997 to Corrado et al., which is hereby incorporated by reference, discloses a system for axially reciprocating a tacky roller (also referred to herein as a contact cleaning roller, or “CCR”) across a substrate being cleaned by the roller. Such reciprocation is useful for spreading particles which may be non-uniformly distributed on the substrate surface over a broader area of the CCR collecting surface, thereby decreasing the rate of decay of collecting efficiency, improving the average cleanliness of the treated substrate, and extending the operating lifetime of the CCR between renewals. In the prior art, the CCR is mounted in a movable frame which is journalled in linear bearings and is displaceable axially of the shaft by a controllable actuator. 
         [0003]    To avoid scratching or scrubbing of the substrate surface by the CCR while the roller is simultaneously rolling along the surface in a first direction and axially sliding across the surface in a second and orthogonal direction, the rate of axial displacement is preferably very low; that is, the ratio of axial to rotational linear velocities is preferably between about 0.01 and about 0.0001. In practice, therefore, the reciprocating actuator may be required to operate at about 1 cycle per minute (cpm) or even less. It can be expensive and difficult to provide an actuating system having the capability for such smooth, slow motion. Such a system may require an actuator, air or hydraulic supply, and an electronic controller having this capability. In addition, such a system is subject to unwanted variation from misadjustment, wear, and drift in electronic and pneumatic components. 
         [0004]    A mechanical system for smoothly oscillating a roller is disclosed in U.S. Pat. No. No. 5,855,172 issued Jan. 9, 1999 to Corrado et al., which is hereby incorporated by reference. The improved system comprises a shell having an electrostatically active outer surface, the shell being supported by a close-fitting rotatable shaft. The shaft within the shell is provided with a spiral cam groove extending from a first axial location to a second axial location disposed 180° from the first axial location, and then back to the first axial location. A cam follower attached to the inner surface of the shell rides in the cam groove, causing the shell to oscillate axially of the shaft at a frequency of oscillation which is the numerical difference between the rotational frequencies of the shell and shaft. Preferably, the shell is nipped against a backing roller, which may be an idle roller or a driven roller with a moving web substrate passing therebetween in contact with the working surfaces of both rollers. Outboard of the working surfaces, the shaft of the backing roller has a first drive roller having a first diameter, and the shaft of the barrel cam has a second drive roller nipped against the first drive roller and having a second roller diameter slightly different from the first roller diameter. Thus, the shell turns at a rotational frequency imposed by the linear velocity of the web substrate whereas the shaft turns at a different frequency as imposed by the relative diameters of the two speed-controlling drive surfaces, the frequency differential being equal to the oscillation frequency of the shell along the barrel cam. 
         [0005]    A shortcoming of the prior art barrel cam system is that the mechanism that ratios the rotational rates of the shell and the barrel cam is rather cumbersome, requiring a roller pair that extends beyond the limits of the roller shell and includes a drive gear supported by the backing roller, and thus cannot be contained within the shell. Further, the mechanism cannot be contained largely within an axial envelope extension of the shell, making the apparatus unsuited to compact installations such as a “drawer slide” configuration. 
         [0006]    What is needed in the art is a compact barrel cam arrangement that can be contained within a roller shell or largely within the axial envelope extension thereof. 
         [0007]    It is a principal object of the present invention to provide a compact barrel cam system that can axially oscillate a roller rolling along a moving substrate surface. 
       SUMMARY OF THE INVENTION 
       [0008]    Briefly described, a system for oscillating a roller driven by rolling contact with a moving substrate comprises an oscillating assembly and an oscillation mechanism. The oscillating assembly comprises first and second opposed gudgeons rotatably mounted on a shaft, the gudgeons being connected by either a plurality of rods or by the roller itself. The oscillation mechanism comprises a reduction transmission assembly having differently toothed input, intermediate, and output pulleys. A cam groove in an oscillation cam is engaged by one or more oscillation pin(s) operationally connected to the gudgeons. 
         [0009]    The input drive pulley turns with the gudgeons, and the output pulley turns with the oscillation cam. An intermediate double-pulley has second and third pulleys on a common hub. First and second timing belts connect, respectively, the input pulley to the second hub pulley, and the third hub pulley to the output pulley. A currently preferred reduction ratio between the input pulley and the output pulley is about 391:1. 
         [0010]    The pulleys may be toothed pulleys, in which case the reduction ratio is governed by the number of teeth on respective of the toothed pulleys. Alternatively, the pulleys may be non-toothed, in which case the reduction ratio is governed by the diameters of respective of the non-toothed pulleys. 
         [0011]    In a first embodiment, the oscillation mechanism is disposed entirely within the oscillating assembly. In a second embodiment, the oscillation mechanism is contained principally within one of the gudgeons outboard of the oscillating assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
           [0013]      FIG. 1  is an isometric view of a first embodiment in accordance with the present invention; 
           [0014]      FIGS. 2 through 4  are sequential elevational cross-sectional views showing the embodiment shown in  FIG. 1  in, respectively, oscillation right, oscillation center, and oscillation left positions; 
           [0015]      FIG. 5  is an elevational cross-sectional view similar to that shown in  FIG. 3 , showing an oscillation mechanism disposed within an oscillating assembly and gudgeons; 
           [0016]      FIG. 6  is an enlarged view of the oscillation mechanism shown in circle  6  in  FIG. 5 ; 
           [0017]      FIG. 7  is an exploded view of the embodiment shown in  FIGS. 3 and 5 ; 
           [0018]      FIG. 8  is an elevational cross-sectional view taken along line  8 - 8  in  FIG. 6 ; 
           [0019]      FIG. 9  is an isometric view of a second embodiment in accordance with the present invention disposed in a removable mount such as a “drawer slide” mount; 
           [0020]      FIG. 10  is an exploded isometric view of the oscillation mechanism shown in  FIG. 9 ; 
           [0021]      FIGS. 11 through 13  are sequential elevational cross-sectional views showing the embodiment shown in  FIG. 9  in, respectively, oscillation right, oscillation center, and oscillation left positions; 
           [0022]      FIG. 14  is a cross-sectional elevational view similar to that shown in  FIG. 12 ; 
           [0023]      FIG. 15  is an enlarged view of the oscillation mechanism shown in circle  15  in  FIG. 14 ; 
           [0024]      FIG. 16  is an exploded view of the oscillation mechanism shown in  FIG. 15 ; and 
           [0025]      FIG. 17  is an elevational cross-sectional view taken along line  17 - 17  in  FIG. 15 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0026]    Referring to  FIGS. 1 through 5 , a first embodiment  100  of an apparatus for axially oscillating a roller in accordance with the present invention comprises optionally an oscillation tubing sleeve  102  captured between first and second end gudgeons  104 , 106  slidably mounted via respective bearings  108 , 110  on a non-rotatable shaft  112 . The gudgeons are connected by a plurality of tie bars  113 , preferably two, within sleeve  102 . In operation, the oscillation tubing sleeve and gudgeons are caused to oscillate on the shaft between right and left extremes  114 , 116  of oscillation as shown in  FIGS. 2 through 4  and described in detail below. This assembly, referred to herein as an oscillating assembly  118  of embodiment  100 , is receptive of a removable/replaceable roll of a working material such as a tape roll or a contact cleaning roll  119  between gudgeons  104 , 106  and over sleeve  102  if optionally present, through which oscillating assembly  118  is rotatably driven by frictional contact with a moving substrate (not shown). 
         [0027]    Referring now to  FIGS. 5 through 8 , wholly self-contained within oscillating assembly  118  is oscillation mechanism  120  that is fixed in axial position to shaft  112  but is freely rotatable thereupon as described below. 
         [0028]    Oscillation mechanism  120  comprises an oscillation cam  122  having at least one spiral groove  124  formed in the surface thereof for receiving at least one oscillation pin  126  fixed in at least one of tie bars  113  and extending radially inward therefrom. Oscillation cam  122  includes a first timing pulley  123 . Oscillation cam  122  is supported by a two-part rotatable hub  128  comprising hub portion  128   a  and hub portion  128   b  extending through cam  122  and first timing pulley  123  and joined during assembly of mechanism  120 . Assembled hub  128  is supported for rotation on shaft  112  by respective bronze shouldered bushings  129 , at least one of which preferably is keyed via keys  131  to hub portion  128   a  and is retained in position by clamp collar  127 . Hub portion  128   a  is provided with at least one notch  130 , and preferably two, for engaging at least one of tie bars  113 , as shown in  FIG. 8 , and also includes a second timing pulley  132 . Hub portion  128   b  supports an arbor  133  for pulley hub  134  having integral third and fourth timing pulleys  136 , 138  disposed on opposite sides of arbor  133 . Pulley hub  134  is rotatably supported on bronze shaft  140  extending from end plate  142 . A first timing belt  144  is connected to first timing pulley  123  and third timing pulley  136 . A second timing belt  146  is connected to second timing pulley  132  and fourth timing pulley  138 . 
         [0029]    Shaft  112  is prevented from rotation by pin  152  and from axial chucking by retaining rings  154 . 
         [0030]    The numbers of teeth in the four timing pulleys and in the two timing belts are carefully selected to provide for a desired ratio of rotation rate about shaft  112  between oscillating assembly  118  and oscillation mechanism  120 . Thus the timing pulleys and timing belts define a reduction transmission  150  having a fixed reduction ratio. 
         [0031]    Note that the embodiment just described comprises toothed pulleys and toothed belts, in which case the reduction ratio is governed by the number of teeth on respective of the toothed pulleys. Alternatively, the pulleys may be non-toothed, in which case the reduction ratio is governed by the diameters of respective of the non-toothed pulleys. 
         [0032]    Note further that pinion gears may be substituted for toothed pulleys; in a special case, belts  144 , 146  may be omitted and the pinion gears meshed directly, wherein the reduction ratio is governed by the respective numbers of teeth on the pinion gears. In an additional special case, the teeth may be omitted from the pinion gears, resulting in the “pulleys” being smooth rolls meshed together and driven by friction, wherein the reduction ratio is governed by the respective diameters of the smooth rolls. 
         [0033]    Therefore, as referred to herein and in the claims, all such rotatable transmission elements are referred to as “timing elements” which should be taken generically to mean either a conventional pulley having a continuous outward-facing groove surrounding a hub, which groove may or may not be toothed; a conventional pinion gear; or a non-toothed roller. 
         [0034]    Example of preferred embodiment: As mechanism  120  rotates on shaft  112 , typically being driven by a moving substrate such as a web or contact cleaning roller, mechanism  120  causes rotation of oscillation sleeve  102 , gudgeons  104 , 106 , and oscillation tie bars  113 . The oscillation tie bars cause hub  128  to rotate and allow oscillation assembly  118  to also oscillate axially of shaft  112  because oscillation pin  126  travels in spiral groove  124  of oscillation cam  122 . 
         [0035]    Hub  128  drives second timing pulley  132 , which drives fourth timing pulley  138  and attached third timing pulley  136  via second timing belt  146 , which drives first timing pulley  123  via first timing belt  144 , first timing pulley  123  being connected to oscillation cam  122 . 
         [0036]    Preferably, first timing pulley  123  which turns with oscillation cam  122  contains 49 teeth; second timing pulley  132  which turns with hub  128  contains 46 teeth; third timing pulley  136  and fourth timing pulley  138  which turn together contain respectively 17 teeth and 16 teeth; first timing belt  144  contains 57 teeth; and second timing belt  146  contains 55 teeth. The net result is that oscillation assembly  118  oscillates axially of shaft  112  at the rate of 1 full oscillation cycle per 391 revolutions of roll  120 . 
         [0037]    Referring now to  FIGS. 9 through 17 , a second embodiment  200  of an apparatus for axially oscillating a roller in accordance with the present invention is shown. A working roller  219  is captured between two spring-biased gudgeons  204 , 206 . In this embodiment, working roller  219  is the only element between the gudgeons; oscillating assembly  218  and oscillation mechanism  220  are disposed entirely within and adjacent to first gudgeon  204  which is slidably mounted on a non-rotatable shaft  212 . First gudgeon  204  includes a well  207  for receiving oscillating assembly  218 . Second gudgeon  206  is also slidably mounted on a second stub shaft  212   a.    
         [0038]    In operation, working roller  219  and gudgeons  204 , 206  are caused to oscillate on shafts  212 , 212   a  between right and left extremes of oscillation  214 , 216  as shown in  FIGS. 11 through 13  and described in detail below. This assembly, referred to herein as an oscillating assembly  218  of embodiment  200 , is rotatably driven by frictional contact of working roller  219  with a moving substrate (not shown). 
         [0039]    Referring now to  FIGS. 14 through 17 , oscillation mechanism  220  is fixed in axial position to shaft  212  but is freely rotatable thereupon as described below. 
         [0040]    Oscillation mechanism  220  comprises an oscillation cam  222  having at least one spiral groove  224  formed in the surface thereof for receiving at least one oscillation pin  226  installed through the wall of gudgeon well  207  and extending radially inward therefrom. Preferably, a plurality of pins  226  are employed to prevent cocking of the mechanism on the shaft. Oscillation cam  222  includes a first timing pulley  223 . Oscillation cam  222  is bounded by respective bronze thrust washers  229 . A second timing pulley  232  is disposed on shaft  212 . Pulley hub  234  has integral third and fourth timing pulleys  236 , 238  disposed on opposite ends of hub  234 . Pulley hub  234  is rotatably supported on bronze shaft  240  extending from bearing housing  242 . A bearing cap  243  closes bearing housing  242 . A first timing belt  244  is connected to first timing pulley  223  and third timing pulley  236 . A second timing belt  246  is connected to second timing pulley  232  and fourth timing pulley  238 . 
         [0041]    Shaft  212  is journalled for rotation in double roller bearings  260  separated by bearing spacers  262  and disposed in bearing housing  242 . 
         [0042]    Shaft  212  is slotted at the inner end  264  and is further provided with a counterbore  266  for receiving a compression spring  268  to counteract the force of the biasing spring in gudgeon  206 . A drive pin  270  is disposed transversely of shaft  212  in compressive engagement with spring  268 . During assembly, gudgeon  206  is installed over shaft end  264  and in interior engagement within well  207  with drive pin  270 . Thus when gudgeon  206  is rotated in operation, shaft  212  is caused to rotate by drive pin  270 . The installation of oscillation pin(s)  226  retains the gudgeon in place. 
         [0043]    A flat  272  on shaft  212  engages second timing pulley  232  to cause the pulley to rotate with shaft  212 . 
         [0044]    The numbers of teeth in the four timing pulleys and in the two timing belts are carefully selected to provide for a desired ratio of rotation rate between oscillating assembly  218  and oscillation mechanism  220 . Thus the timing pulleys and timing belts define a reduction transmission  250  having a fixed reduction ratio. 
         [0045]    Note that the embodiment just described comprises toothed pulleys and toothed belts, in which case the reduction ratio is governed by the number of teeth on respective of the toothed pulleys. Alternatively, the pulleys may be non-toothed, in which case the reduction ratio is governed by the diameters of respective of the non-toothed pulleys. 
         [0046]    Note further that pinion gears may be substituted for toothed pulleys; in a special case, belts  244 , 246  may be omitted and the pinion gears meshed directly. 
         [0047]    In either case, as referred to herein and in the claims, the term “pulley” should be taken generically to mean either a conventional pulley having a continuous outward-facing groove surrounding a hub, or a conventional pinion gear. 
         [0048]    Example of preferred embodiment: As roll  219  rotates, typically being driven by a moving substrate such as a web or contact cleaning roller, roll  219  rotates gudgeons  204 , 206 , causing shaft  212  to rotate and allowing oscillation assembly  218  to also oscillate axially of shafts  212 , 212   a  because oscillation pin(s)  226  travels in spiral groove  224  of oscillation cam  222 . 
         [0049]    Shaft  212  drives second timing pulley  232 , which drives fourth timing pulley  238  and attached third timing pulley  236  via second timing belt  246 , which drives first timing pulley  223  via first timing belt  244 , first timing pulley  223  being connected to oscillation cam  222 . 
         [0050]    Preferably, first timing pulley  223  which turns with oscillation cam  222  contains 49 teeth; second timing pulley  232  which turns with shaft  212  contains 46 teeth; third timing pulley  236  and fourth timing pulley  238  which turn together contain respectively 17 teeth and 16 teeth; first timing belt  244  contains 57 teeth; and second timing belt  246  contains 55 teeth. The net result is that oscillation assembly  218  oscillates axially of shafts  212 , 212   a  at the rate of 1 full oscillation cycle per 391 revolutions of roll  219 . 
         [0051]    While the invention has been described by reference to various specific embodiments, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiments, but will have full scope defined by the language of the following claims.