Abstract:
Log indexing apparatus includes a frame and a series of laterally spaced spiral rolls that are inclined from front to back between the infeed and the outfeed, and are also inclined sideways. The spiral rolls are rotated synchronously and are arranged so that the gaps between the flights of the spirals define an upward moving log-receiving trough across the width of the device. The sideways inclination reduces the tendency of the logs to ride on the edges of the flights of the spirals.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    This invention relates to devices for unscrambling, singulating and ending logs.  
         BACKGROUND OF THE INVENTION  
         [0002]    The invention is used to unscramble bundles of logs and to promote the logs from the bundle to another, usually higher, location. Generally speaking, devices that do this are well known. Such devices are sometimes called indexing apparatus, unscramblers or singulators. The term “singulator” refers to the fact that the devices are usually designed to deliver a single log at a time to an outlet of the device.  
           [0003]    Examples of prior art unscrambling and singulating devices are found in U.S. Pat. No. 5,653,570 to Weirathmueller; U.S. Pat. No. 5,257,688 to Fridlund; U.S. Pat. No. 5,423,417 to Redekop and Canadian Patent No. 1,091,611 to Hallstrom.  
           [0004]    One form of singulator that is relatively well known comprises a series of steps moving along an incline from an inlet location to an outlet location. Two groups of reciprocating cooperate so as to gradually promote logs toward the outlet. Such devices are typified by Canadian Patent No. 1,277,682 to Ekholm.  
           [0005]    Another form of singulator is described in U.S. Pat. No. 5,119,930 to Stelter. The &#39;930 patent relies on multiple stages of movable quadrants to promote and singulate logs. The top portion of each quadrant presents a log supporting shelf that diminishes in size against a fixed surface as the quadrant moves through an arc so as to limit the number of logs promoted to the next stage.  
           [0006]    The foregoing systems each involve step-wise reciprocating motion. Such motion in heavy machinery generates significant noise, and the repetitive contact between parts causes considerable wear.  
           [0007]    It is an object of the present invention to provide an alternative yet effective approach to unscrambling and singulating logs.  
           [0008]    It is a further object of this invention to provide such a device that is self-cleaning, that automatically ends logs, and in which both noise and wear is reduced in relation to prior art systems.  
         SUMMARY OF THE INVENTION  
         [0009]    The present invention provides a series of laterally spaced inclined spiral rolls extending between an inlet location where logs are received in a bundle, and an outlet location at a higher elevation than the inlet location.  
           [0010]    The outlet is rearwardly offset in relation to the inlet so that the spiral rolls have a front to back inclination. The spiral rolls of the invention are also inclined sideways, i.e. they define on angle in relation to the feed direction. The spiral rolls comprise a pipe roll and a flange or “flight” wrapped around the pipe roll to define a spiral or helix about the length of the pipe roll. The gaps on the pipe roll between successive revolutions of the flight are aligned with the gaps on the adjacent spiral rolls. The series of adjacent gaps across the plurality of spiral rolls defines an elongated log-receiving trough. The spin of the spiral rolls is also synchronized so as to promote the log-receiving trough in an even upward motion. In the area of the infeed, the action of the spiral flights digging into the log bundle assists in dislodging individual logs and urging them into the log-receiving trough.  
           [0011]    The resulting device has the advantage of continuous action, thereby avoiding the repetitive loud banging associated with prior art singulators, and reducing wear on the moving parts.  
           [0012]    Another advantage of the invention is that the logs are continuously “ended” in one direction by the turning action of the spiral rolls. Ending the logs refers to aligning the end of a log against a reference surface. Such ending assists in measuring the logs and in controlling subsequent advancement and cutting operations for the log.  
           [0013]    It is a further feature of the invention that the sideways inclination of the spiral rolls allows the logs to more closely abut the face of the helical flights. Without such a sideways angle, the logs would ride on the sharp edges of the flights thus impeding smooth progress of the logs.  
           [0014]    Other aspects of the invention will be appreciated by reference to the detailed description that follows and are more particularly defined by the claims.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]    The invention may be more fully appreciated by reference to the following description of the preferred embodiment and by reference to the drawings thereof in which:  
         [0016]    [0016]FIG. 1 is a view of the preferred embodiment of the invention;  
         [0017]    taken from a point above and normal to the spiral rolls;  
         [0018]    [0018]FIG. 2 is a side elevation of the preferred embodiment;  
         [0019]    [0019]FIG. 3 is a front view of roller chain and bracket assemblies for two of the spiral rolls;  
         [0020]    [0020]FIG. 4 is a view of an alternative embodiment of the invention, taken from a point above and normal to the spiral rolls; and  
         [0021]    [0021]FIG. 5 is a side elevation of the alternative embodiment of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]    [0022]FIG. 1 illustrates a spiral singulator  10  according to the invention. A plurality of spiral rolls  12  are mounted on a frame  14 .  
         [0023]    Referring FIG. 2, the spiral singulator  10  delivers logs from an inlet location (infeed)  16  where the logs are received in a scrambled and unsingulated bundle, to the outlet location (outfeed)  18  to which the device delivers singulated and ended logs. Infeed  16  includes an inclined skid plate  20  for receiving and holding a bundle of randomoly distributed logs. The outfeed location is rearwardly offset in relation to the infeed location.  
         [0024]    Frame  14  comprises vertical members  22  at the rear of the singulator, horizontal base members  24  extending from front to back of the singulator and diagonal bracing members  26 . Upper cross member  28 , intermediate cross member  30 , and cross members  32  and  34  extend across the width of the device.  
         [0025]    Skid plate  20  extends at an incline from intermediate cross member  30  upward and toward the front of the singulator. The bottom of skid plate  20  is braced against a series of spaced bearing pedestals  36 , only one of which is visible in FIG. 2. The bottom of the spiral roll extends through an opening at the bottom of skid plate  20 , as best illustrated in FIG. 3. The top of the skid plate is braced against an infeed frame  38  (FIG. 2).  
         [0026]    Referring to FIGS. 1 and 2, a plurality of spiral rolls  12  are spaced laterally from one another across the width of the singulator  10 . Spiral rolls  12  are inclined from front to back between the bottom portion of the infeed  16  and the outfeed  18 . This front to back inclination corresponds to the feed direction indicated by arrow  47 . It will be appreciated that the feed direction extends along a straight line between the infeed and the outfeed locations, the line being normal to both. In the preferred embodiment, the front to back inclination of the spiral rolls (as best seen in FIG. 2) is about 50° to the horizontal. However the specific angle of front to back inclination will depend on the size of the logs to be fed by the device, the height of the flights on the pipe rolls and the number of spiral rolls available to support a given log. It is contemplated that any angle between 10° and 80° would be within the scope of the present invention.  
         [0027]    Each spiral pipe roll  12  comprises an elongated pipe roll  40  to which a flange or flight  42  has been helically welded about the length of the roll to define a spiral shape. The spiral configuration defines a series of gaps  44  between successive revolutions (e.g.  46 ,  48 ) of the flight. The flights may be arranged in either a right hand or left hand screw configuration, the right hand configuration being shown in the drawings. Thus rotation of the spiral rolls clockwise (as indicated by arrow  17 ) when viewed from the top of the spiral rolls promotes the gaps upward.  
         [0028]    The laterally adjacent plurality of spiral rolls  12  are arranged such that their gaps  44  and flights  42  are horizontally aligned as seen in FIG. 1 so as to define an elongated log-receiving trough  49  extending across the width of the singulator  10 .  
         [0029]    The flights  42  on the spiral rolls  12  define a helical face angle, namely the angle defined between the face of the flight and the longitudinal axis of the roll.  
         [0030]    In addition to being inclined from front to back, spiral rolls  12  are also inclined sideways as seen in FIG. 1, i.e. their longitudinal axes define an angle of less than 90° in relation to the transverse axis (side to side) of the singulator. In the preferred embodiment, this angle is about 71°. Taken in relation to the vertical, the sideways angle is about 19°. This may also be viewed as an offset angle in relation to the feed direction  47 . This inclination allows the logs in the log-receiving trough  49  to come into fuller face contact with the face of the flights  42 . Absent such inclination, the logs would rest on the relatively sharp outer edges of the flights thereby causing the flights to dig into the logs, or to catch on branches, notches or imperfections in the logs and thereby impede progress of the logs. Maximizing contact with the face of the flights and minimizing contact with their edges encourages smooth promotion of the logs upwards. The specific angle of sideways inclination may vary, however preferably the sideways angle as defined in relation to the vertical to be close to the helical face angle so as to allow presentation of the face of the flight to the side of the log. It is contemplated that any sideways angle in relation to the vertical that is within 35° of the helical face angle is within the scope of the invention.  
         [0031]    Each spiral roll  12  is mounted for rotation at its lower end in a bushing  50  within a bracket  52 . Each bracket  52  is mounted on a support plate  53  mounted on a block  52  that is in turn secured to a bracket  53  and a bearing pedestal  36 . Bearing pedestal  36  extends between cross member  32  and intermediate cross member  30 . The bearing pedestals may also be used to support the skid plate  20 .  
         [0032]    The top of the spiral roll is mounted for rotation on an end plate  55  extending diagonally from upper cross member  28 .  
         [0033]    Referring to FIG. 3, the lower end of each spiral roll include sprockets  54 ,  56  at each side of bushing  50 . A roller chain  58  engages the upper sprocket  56  of one spiral roll  12   a  and the lower sprocket  56  of the adjacent spiral roll  12   b . This drive linking across successive spiral rolls allows them to be driven in synchronism by a motor (not shown). As a result, coordinated rotation of the spiral rolls will promote the log-receiving trough  49  upwards at a rate consistent across the width of the singulator.  
         [0034]    The lateral spacing between adjacent spiral rolls is approximately one foot in the preferred embodiment. This allows logs and larger debris to be promoted upward while allowing smaller debris to fall between the rolls. This provides a self-cleaning feature for the device and may be effective for spacings between 6″ and 18″.  
         [0035]    Dragon backs  60  of a thickness of about ¾ of an inch are provided between adjacent spiral rolls  12 . The teeth of the dragon backs serve to engage the upward moving log and cause it to rotate. This rotation in turn expels other logs that might have seated themselves in the same log-receiving trough. This feature enhances the singulating activity of the device to ensure that only one log at a time is promoted to the outfeed. Dragon backs  60  are mounted on bars  61  extending parallel to the spiral rolls  12  from the bottom of the rolls to about the mid point of the rolls. Bars  61  are supported by frame members (not shown) such that logs in log-receiving trough  49  do not come into contact with the roll surfaces in the area of the gaps  44  until the log has been promoted in the feed direction past the dragon backs  60 .  
         [0036]    As all spiral rolls  12  rotate in synchronism, logs are picked out of the bundle of logs at the infeed  16  by the action of flights  42  and one or more logs are urged into the log-receiving trough  49 . The trough  49  moves upward in the direction of arrow  47 . As the trough moves past the dragon backs  60  additional singulating takes place. The log is ultimately discharged at the outfeed  18  onto ramp  63  and a conveyor.  
         [0037]    An alternate method of causing the log to rotate instead of using dragon backs  60  is to incline the spiral rolls  12  several degrees less than the full face angle of the flights  42 . As a result the edges of the flights come into contact with the logs rather than the full face of the flight. The rotational action of the edges of the flights coming into contact with the log at this reduced angle will tend to lift the log slightly, thus causing it to rotate. This is the same effect the dragon backs have, but as a result of contact with the edges of the flights instead of the dragon backs. This rotation expels other logs that might have seated themselves in the same log receiving trough. Bars  61  are still used with this roll configuration.  
         [0038]    In an alternative embodiment illustrated in FIGS. 4 and 5, the bars, or decline retarder fins  61   a , are positioned such that they decline in relation to the spiral rolls  12 . Because of the decline slope of the decline retarder fins  61   a , logs come into increased contact with the spiral flight  42  as they are promoted in the feed direction. Therefore, at the infeed point  16 , where the bars  61   a  extend the furthest distance above the surface of the rolls  12 , the logs have minimal contact with the spiral flight  42 , thereby enhancing the singulation activity as logs are only drawn off the bottom of the deep pile of logs. This angled positioning of the decline retarder fins  61  allows for preliminary singulation at the infeed  16  such that one or more logs are urged into the log-receiving trough  49 . Further singulation takes place through rotation imparted by edges of the flights as described above.  
         [0039]    As a further alternative, not shown, dragon backs  60  could also be affixed to the decline retarder fins  61   a  in order to impart additional rotation to the logs. Different combinations of the slope of the bars  61  and  61   a , the incline of the spiral rolls and the use of dragon backs may be used in order to control the singulation process of different sized logs.  
         [0040]    The turning action of the spiral rolls is partially imparted to the log by the face of the flights  42  resulting in a slight displacement of the log in the direction of arrow  67 . More pronounced lateral displacement occurs when the log rests on the body of the spiral roll in the area of gaps  44 . The turning action of the roll propels the log toward an ending side plate  66 . As a result, the logs are effectively ended against ending side plate  66  by the time they reach the outfeed. As premature ending may result in dragging of the log along side plate  66 , the bars  61  and dragon backs  60  are arranged to be at a higher elevation than the body of the spiral rolls in the area of the gaps  44  adjacent the bars. By doing so, aggressive ending action is delayed until the log approaches the outfeed  18 .  
         [0041]    It will be appreciated by those skilled in the art that certain deviations from the preferred embodiment described herein may be practised and certain alterations may be made without departing from the scope of the invention.