Abstract:
The band saw self cooling roller guide is defined by a main cylindrical roller body having a front portion of reduced diameter forming a collar for mounting coaxially around a shaft, and a flange extending from the rear portion thereof forming a shoulder. The thin rear edge of the band saw blade or ribbon abuts the flange which aids in aligning the blade, and the flat surface of the blade rests upon a plurality of grooves formed around the peripheral surface of the main roller body. A plurality of apertures such as louvered holes are formed in the face of the body and extend through the flange to funnel air their the rotating roller body cooling the roller, aligning the blade, and extending the wear thereof.

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   This invention relates generally to band saws and more particularly to a flanged guide roller with air flow passages there though to help dissipate heat from the roller during use thereof. 
   2. Background of the Invention 
   Conventionally band saws have a pair of blade guides which are located one on each of respective opposite sides of the active cutting portion of the saw blade. One known conventional band saw guide comprises a pair of slide blocks spaced apart from one another and mounted on a backing plate. The saw band passes through the gap between the slide blocks that are closely adjacent but spaced from opposite faces of the blade and the backing plate engages the edge of the blade to counteract forces imposed on the blade during cutting. The slide blocks are located rearwardly from the teeth because of their set to cut a kerf that is wider than the blade thickness. There may also be rollers that rollingly engage opposite faces the blade and by way of example of the same reference maybe had to U.S. Pat. No. 4,290,330 granted Sep. 22, 1981 to I. Washio et al and entitled “Bandsaw Blade Guiding Apparatus”. 
   Another known guide comprises a pair of rollers that rollingly engage respective opposite faces of the band blade and a third roller that rollingly engages the back edge of the blade. The rollers do not generate as much heat as do the slide blocks from frictional engagement with the blade. 
   A still further blade guide comprises a roller that has an outwardly projecting flange on one edge thereof. The rear edge of the blade engages the flange and a face of the blade engages the outer face of the roller. The one roller guide is much simpler than some of the other arrangements but the useful life of roller is shortened by heat generated by frictional contact of the blade with the roller and particularly the sliding contact between the rear edge of the blade and the flange on the guide roller. By way of example of a flanged roller blade guide reference may be had to U.S. Pat. No. 2,688,990 granted Sep. 14, 1954 to W. Bushey et al and entitled “Band Saw Guide” The disclosed guide employs a back-up roller for each of the respective pair of guide rollers. 
   SUMMARY OF INVENTION 
   The band saw self cooling roller guide is defined by a main cylindrical roller body having a front portion of reduced diameter forming a collar for mounting coaxially around a shaft, and a flange extending from the rear portion thereof forming a shoulder. The thin rear edge of the band saw blade or ribbon abuts the flange which aids in aligning the blade, and the flat surface of the blade rests upon a plurality of grooves formed around the peripheral surface of the main roller body. A plurality of apertures such as louvered holes are formed in the face of the body and extend through the flange to funnel air through the rotating roller body cooling the roller, aligning the blade, and extending the wear of the roller and blade. 
   A principal object of the present invention is to provide a flange type guide roll that incorporates means to dissipate some of the heat therefrom generated therein during use. 
   In keeping with the forgoing there is provided a bandsaw blade roller guide comprising a body member having a front face and a rear face and mountable for rotation about an axis passing through the faces. The body member having an outer peripheral surface parallel to the axis for rollingly engaging a side flat face the band saw blade and a flange extending outwardly therefrom. The flange has a front face surface disposed perpendicular to the peripheral surface for engaging the rear edge of the bandsaw blade. The body member has a plurality of passages extending there through with inlets thereto in the rear face and outlets therefrom in the front face. The body member includes means adjacent the inlets such as apertures, to cause air to flow through the passages during rotation of the roller. Moreover, the apertures may include through bores angled forming louvers for funneling air through. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the several views and wherein: 
       FIG. 1  is a front oblique view of the present invention showing a bandsaw roller guide of the present invention; 
       FIG. 2  is a rear oblique view of the present invention showing the roller guide shown in  FIG. 1 ; 
       FIG. 3  is a perspective side view of the present invention showing a roller journalled on a roller mounting shaft; 
       FIG. 4  is a partial perspective view of a prior art embodiment of a conventional bandsaw showing a conventional vertical mounted guide roller and conventional horizontally mounted guide roller on the left hand side of that same cutting portion of the blade mounted to an arm guide; 
       FIG. 5  is a partial perspective view of the present invention showing the use of horizontally mounted roller guide supporting a band face, wherein the roller guide has cooling apertures forming air flow through passages therein used in combination with conventional roller guide mounted vertically engaging the rear edge of the blade wherein both rollers are mounted to a roller guide back plate; 
       FIG. 6  is a partial perspective view of a preferred embodiment of the present invention showing a blade guide roller having a rear flange, cylindrical body member including grooves and ridges therearound, and air flow through passages formed in the face of the body, wherein the guide roller is mounted on the right hand side of the active cutting portion of the blade to a conventional arm guide; 
       FIG. 7  is a partial perspective view of the present invention showing the use of horizontally mounted roller guide having a cylindrical body with grooves and ridges therearound supporting a band blade face and a flange forming a shoulder for supporting the end edge of the band blade, wherein the roller guide has cooling apertures forming air flow through passages therein mounted to a roller guide back plate; 
       FIG. 8  is a partial perspective view of the roller guide of  FIG. 7  shown attached horizontally to a mounting plate which is mounted to the saw frame utilizing a pivoting member thereinbetween to adjust the angle of roller guide and saw band blade resting thereon; 
       FIG. 9  is a perspective view of the mounting plate assembly showing a pair of open plates showing a groove thereinbetween for cooperative engagement with a cylindrical member disposed therein having a slightly larger diameter than the grooves in order for the plates to pivot thereabout in the vertical direction; 
       FIG. 10  is a side view of the mounting plate assembly of  FIG. 9 ; 
       FIG. 11  is a practical perspective view of the present invention showing a left handed saw wherein the blade is rotating clockwise and the lumber to be cut would pass between the spaced apart mounting blocks, showing a guide roller with a shoulder flange and grooves around the cylindrical body on the blade receiving end and a guide roller with a shoulder flange and grooves around the cylindrical body including air flow passages formed therethrough positioned on the blade and saw dust exiting end; 
       FIG. 12  is a perspective side view of an alternate embodiment of the present invention showing a roller journalled on a roller mounting shaft including a sloped collar; 
       FIG. 13  is a front oblique view of an alternate embodiment of the present invention showing a bandsaw roller guide of the present invention without a collar portion; and 
       FIG. 14  is a rear oblique view of the invention of  FIG. 12  showing the air passages formed therethrough. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 4 and 5  of the drawings there is diagrammatically illustrated a portion of a band saw  10  having a pair of blade guide rollers  20  spaced apart from one another longitudinally along a selected active cutting length portion  11 A of the bandsaw blade  11  to guide the same and counteract forces imposed thereon during cutting. The blade  11  is an endless band with respective opposite flat side faces  13  and  14 , a plurality of teeth  15  along the front cutting edge and a rear edge  16  disposed opposite said front cutting edge. The bandsaw blade  11  is supported by a pair of wheels or drums in alignment and spaced apart from with one another supported on a frame and powered by one or more electric motors. Conveyors transport the logs or beams of wood normal to and inbetween the drums at a selected height for contact with the bandsaw blade which cuts planks therefrom as the wood is pushed through the blade. Conventional guide rollers  5  consist of a wheel or disc on a bearing having a smooth pheripheral surface for contacting the band saw blade face or rear edge of the band saw blade. 
   A preferred embodiment of each guide roller depicting preferred embodiments of the present invention is best illustrated in  FIGS. 1-3 ,  5 , and  12 - 14 . The guide roller  20  shown best in  FIGS. 1-3  and  8 , comprises a generally cylindrical body member  18  having respective front and rear faces  22  an  23  and an outer peripheral surface  24  formed having at least one circumferential groove  17 , and preferably a plurality of alternating circumferential grooves  17  and ridges  37  therearound formed into the surface by cutting, grinding, molding or the like, that rollingly engages one of the flat side face  13  or  14  of the saw blade. The body member  18  is journalled for rotation on a mounting shaft or bolt  25  by means of a suitable bearing  26  (preferably including a grease seal  56 ) mounted on a spindle of shaft  19 . A flange  27  extends outwardly from the peripheral surface  24  of the rear portion of the body  18  forming a first shoulder  38 . The shoulder  38  extending normal to the body of the flange  27  forms a front face  28  for engaging the rear edge  16  of the blade  11 . The distance from the face  27  to the edge of the peripheral surface  24  is less than the distance from the band rear edge  16  to the root of the cutting teeth as is conventional in the art. 
   In accordance with the present invention the front portion of the roller body  18  is formed having a reduced external diameter forming a cylindrical member or collar  21  and second shoulder  40  connecting normal thereto whereby the shoulder  40  forms the front face  22  of the roller body. In an alternate embodiment illustrated in  FIGS. 13 and 14 , the roller body  18  does not include the collar  21  and the front face extends flush with the end of the roller body  18 . In another preferred embodiment illustrated in  FIG. 12 , the collar  21  extends upward to the face  22  of the roller body is sloped at an angle intersecting the roller body at shoulder  40 . 
   While the guide roller  20  positioned on the exit side of the mill defining the second roller with respect to the direction of rotation of the saw blade gets extremely hot due to the hot saw dust interacting therewith carried thereto by the saw blade due to the friction associated with the blade pulling the saw dust through the lumber being cut. The heat buildup tends to cause the blade to warp and wallow when hot and cut in a wavy pattern often resulting in a reduced feed speed. In order to dissipate the heat and remedy the warping problem, a plurality of air flow passages are utilized within the exit guide roller  20 . More particularly, the roller body  18  has a plurality of air flow through passages  30  extending from one to the other of the front and rear faces  22  and  23 , respectively. Air is caused to flow through the passages  30  in a direction from the rear face  23  to the front face  22  by air flow causing means as the roller during operation rotates in the direction of arrow A in FIG.  2 . The air flow causing means, in the illustrated embodiment, comprises an entry portion  31  in the rear fare  23  for each respective passage  30  and wherein the entry portion  31  is a concave depression. The depression may be variously formed for example by a portion of a drill hole whose axis of rotation is at a selected angle to the longitudinal axis of the passage  30  associated therewith. The concave depression has a leading portion  32  sloping gently from a leading edge  29  toward a trailing edge  33  defining the leading edge of an inlet  34  to the passage and terminating in a rear wall  35  adjacent a trailing edge  36  of the inlet  34 . The rear wall  35  is approximately at right angles to the surface of the rear face  23  at its steepest central portion and merges via curved surfaces of gradually decreasing slope into the gently sloping leading portion  32 . Alternatively the air flow causing means maybe appropriately shaped and appropriately positioned projections or fins  50  on the surface  23  and/or flange  26  as shown in the embodiment of FIG.  10 . 
   The guide roller  46  positioned on the entry side of the saw blade is not exposed to hot saw dust and may be utilized having rear flange  27  for biasing the blade and a flat surface without grooves or air passages within the body; however, a preferred embodiment would still utilize grooves  17  and ridges  37  on the roller body to aid in cooling and positioning of the blade thereon. 
   Of course, both the entry and exit rollers may be formed having rear flanges  27 , grooves  17  and ridges  37  on the roller body, and air passages therethrough; however, it is contemplated that one or more of these features can be utilized independently or together to obtain an improvement over existing wheel type roller bearings. Also, the improved guide rollers of the present invention may be used in combination together or with conventional rollers to effect an improved degree of wear over conventional rollers provided the improved rollers are utilized in the exit position of the saw blade subjected to the hot saw dust. 
   Of course the guide rollers can be used with the conventional arm guide or combined with the adjustable roller guide plate to provide a novel and effective means of adjusting the pitch of the saw blade. As shown in  FIGS. 4 and 6 , the present invention is used in combination with an adjustable arm  52  which is reciprocated by a hydraulic cylinder or preferably an air cylinder having a piston with a selected stroke in an effective range which, for the preferred embodiment of the present invention is about 10 inches. 
   As illustrated in  FIGS. 5 ,  7 , and  9 - 11 , the adjustable roller guide plate  54  comprises a first inner stationary plate  56  having a plurality of holes  58  for bolting the plate  56  to the frame  58  of the saw. A shallow groove  60  is formed along the horizontal axis of the interior surface  62  thereof. A plurality of through slots  70  are formed in the stationary plate  56  for cooperative engagement with one or more bolts  71  in order to adjustably position the first stationary plate  56  and movable plate  64  in the desired position on the frame  58  of the saw. 
   A second outer movable plate  64  having mating holes  58  and a shallow groove  60  formed along the horizontal axis of the interior surface  66  are aligned with the holes of the first plate and bolts  68  are used to hold the plates  56  and  64 , respectively, together in alignment. A cylindrical member  72  having a diameter greater than the combined depth of the shallow grooves  60  of the plates  56  and  64  is disposed thereinbetween forming a pivot point along the horizontal axis. Attachment of the roller guide  20  to the exterior surface of the outer plate  64  by means of holding such as bolts  68  extending therethrough provides a means for pivoting the roller guide  20  and changing the angle of the blade supported thereby. 
   At least one means of adjusting the height of the outer plate  64  formed by one or more bolts  74  having a washer or collar  76  threadably extending vertically into the movable plate  64  and abutting the top of the plate  64  or bottom of the movable plate  64  for pushing the movable plate  64  up or down with respect to the stationary plate  56 . 
   The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modifications will become obvious to those skilled in the art based upon more recent disclosures and may be made without departing from the spirit of the invention and scope of the appended claims.