Abstract:
A self-locking collar assembly for a saw blade is provided, in addition to a saw blade per se and a sawing machine characterized by the assembly of the subject invention. The subject assembly preferable and advantageously includes a collar having an inner periphery adapted for receipt upon a spline, with the collar adapted for affixation to a saw blade. A self-locking link is pivotally mounted at an end thereof to a portion of a surface of the collar. The self-locking link includes a spline engaging lobe for axially affixing the saw blade to the spline in furtherance of producing a pre-select dimensional rip of a work piece.

Description:
[0001]     This is a regular application filed under 35 U.S.C. §111(a) claiming priority under 35 U.S.C. §119(e) (1), of provisional application Ser. No. 60/574,745 having a filing date of May 27, 2004. 
     
    
     TECHNICAL FIELD  
       [0002]     The present invention generally relates to a saw blade locking apparatus, more particularly, a self-locking saw blade collar assembly for use in gang rip saws and the like, saw blades so adapted, and sawing machines utilizing same.  
       BACKGROUND OF THE INVENTION  
       [0003]     Historically, gang rip saws, such as those by Mereen-Johnson Machine Co. of Minneapolis, Minn., e.g., Mereen-Johnson Machine Co. Model 400, utilized removable saw sleeves with spacers placed between saw blades to create the desired or sought after net rips. In the context of changeovers for the multiple rip saw (i.e., blade setting or spacing alteration), the method attendant to utilization of the saw sleeves is known to offer high accuracy, however, it requires substantial down time. Recently, the removable saw sleeve approach, and methodology associated therewith, was improved with the introduction of oil or grease-activated expansion mechanisms which allow the setting of saw blades on the gang rip saw without reliance upon a removable sleeve or spacer structure. Although this improved approach or technique reduces set-up time, operators continued to struggle with issues of accuracy, reliability, and maintenance of the required mechanisms. A further and critical drawback of this approach is that when the mechanical system fails, the saw becomes unusable, resulting in costly down time, necessitating costly repairs.  
         [0004]     A further, alternate development to fluid expansion mechanisms for integrating a saw blade and an arbor, e.g., a spline, or spindle is disclosed in U.S. Pat. No. 5,293,798 (Otani et al.). Essentially, a one way, on/off clutch is provided between the saw blades and the spindle. While the spindle is rotating at a low speed or is at a stop, the clutch is in its inoperative position, keeping the saws disengaged from the spindle so that the distances between the adjacent saws can be adjusted freely. When the spindle begins to rotate at a high speed, the clutch is finally activated, by centrifugal force, the spindle thereby engaged, and the saw blades in turn locked the spindle.  
         [0005]     In addition to the aforementioned shortcomings of heretofore known devices and/or methods, it is further critical that the saw blade not move while positioning other blades, or during the locking activation process. Oil/hydraulic expansion systems do not suitably satisfy this requirement, as all blades remain loose until being locked up simultaneously by the expansion mechanism. Similarly, Otani et al. suffer from such saw blade positioning instability, as only an on/off mechanical approach is provide, i.e., as high speed spindle rotation is required for even minimal engagement between portions of the clutch with the spindle, assurance of precise, preselect rips are far from certain. Thus, there remains a need to provided a mechanism by which saw blades may quickly and reliably be axially positioned along a spindle or the like to produce targeted repeated rips with no down time for inadvertent saw blade travel, or more generally, misalignment. Furthermore, it is believed advantageous to provide a simple mechanical mechanism which progressively unites a saw blade with a spindle.  
       SUMMARY OF THE INVENTION  
       [0006]     A self-locking collar assembly for a saw blade is provided, in addition to a saw blade per se and a sawing machine characterized by the assembly of the subject invention. The subject assembly preferable and advantageously includes a collar having an inner periphery adapted for receipt upon an arbor or a spline, with the collar adapted for affixation to a saw blade. A self-locking link is pivotally mounted at an end thereof to a portion of a surface of the collar. The self-locking link includes an arbor or a spline engaging lobe for axially affixing the saw blade to the arbor in furtherance of producing a pre-select dimensional rip of a work piece.  
         [0007]     The subject self-locking collar assembly provides for fast, accurate, and reliable changeovers for saw blades of the multiple rip saw. The assembly provides progressive locking of the saw to the saw arbor or spindle. Advantageously, self-locking collar assembly is for use on gang rip saws that have two or more saw blades on an arbor. The collar is preferably used, for example, with four or five other collars on a single double-keyed 2 9/16″ diameter saw arbor which may be equipped with 12″ or 14″ diameter saw blades. The subject collar utilizes the natural occurrence of centrifugal force generated by the rotation of the saw arbor to simultaneously lock the saw blades into their desired positions.  
         [0008]     Saw position changeover is as easy as stopping the saw arbor, axially moving the saw blade or blades to the new desired position, and restarting the arbor. Due to the configuration of the subject collar, more particularly select structures thereof and their interrelationships, two distinctly different fits are provided for one or more saw blades upon the arbor, one for static (i.e., passive) and one for dynamic (i.e., active) operational modes. More specific features and advantages obtained in view of those features will become apparent with reference to the drawing figures and  DETAILED DESCRIPTION OF THE INVENTION.   
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Referring now to the drawings wherein like numerals are used to designate like parts of the invention throughout the figures:  
         [0010]      FIG. 1  is a perspective sectional view of a sawing machine spline depicting thereon the self-locking collar assembly of the subject invention in combination with a saw blade, portions broken away, a self-locking link shown disengaged from the arbor;  
         [0011]      FIG. 2  depicts an end on view of the perspective sectional view of  FIG. 1 ;  
         [0012]      FIG. 3  depicts the general arrangement of  FIG. 1  wherein the self-locking link is shown in an active or activated operational condition, namely, operatively engaged with the arbor;  
         [0013]      FIG. 4  depicts an end on view of the perspective sectional view of  FIG. 3 ;  
         [0014]      FIG. 5  is a perspective plan view of the self-locking collar assembly of the subject invention;  
         [0015]      FIG. 6  is a partially exploded view of the assembly of  FIG. 5  depicting the relationship between the self-locking link and the collar; and,  
         [0016]      FIG. 7  illustrates the “underside” of the self-locking link of  FIG. 6  and related structures. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     The self-locking collar assembly  10  of the subject invention is generally depicted in  FIGS. 1-6 , and otherwise hidden features of a self-locking link  12  thereof depicted in  FIG. 7 . General functionality of the device  10  is readily appreciated with reference to  FIGS. 1-4 , while the elements or structures thereof are the focus of  FIGS. 5-7 .  
         [0018]     With general reference to  FIGS. 1-4 , the self-locking collar assembly  10  of the subject invention is illustrated in combination with a saw blade  14 , the combination shown received upon a spindle or arbor, more particularly, an arbor  16 . The arrangements or configurations of  FIGS. 1 &amp; 2 , as will later be discussed, generally permit axial translation of the assembly  10  along the spline  16 , whereas, the arrangements or configurations of  FIGS. 3 &amp; 4 , as will also later be discussed, generally prohibit unintended axial translation of the assembly  10  along the spline.  
         [0019]     As a preliminary matter, it is to be noted and readily appreciated that the following description of the subject assembly, particularly the functionality thereof, is illustrative, and is in no way intended to be limiting. For example, in lieu of a “collar” or the like, a saw blade hub or boss may be suitable adapted so as to perform the critical functionality of the assembly to be described.  
         [0020]     Referring again generally to  FIGS. 1-4 , the self-locking collar assembly  10  generally includes a collar  18 , and a self-locking link  12  pivotally mounted at an end thereof to a portion of a surface  20  of the collar  18 . As will be later discussed in relation to  FIGS. 5-7 , the self-locking link  12  is advantageously mounted with respect to the collar  18  so as to be under tension.  
         [0021]     The collar  18 , generally adapted to be affixed to a saw blade  14 , or alternately equivalently provided so as to be integral thereto as by a hub, boss, etc., includes an inner periphery  22  adapted for receipt upon an arbor, more particularly and advantageously, spline  16  as shown. As illustrated, the spline  16  preferably, but not necessarily includes opposingly paired keyways  24  ( FIGS. 1 &amp; 3 ), the collar assembly  10  correspondingly including opposingly paired keys  26  inwardly extending from opposingly paired keyways  28  which traverse a face, i.e., the thickness, of the inner periphery  22  of the collar  18  ( FIGS. 1 &amp; 3 ). The illustrated details of this arrangement are intended as environmental background or context for the subject invention, it being understood that the subject arrangement, including but not limited to alternate, and/or equivalent splined interfaces, is not intended to be limiting.  
         [0022]     As shown, saw integrating fasteners  30  are received through spaced apart through-holes  32 ,  FIG. 5 , in the collar  18  which traverse a thickness thereof. Furthermore, a large relief area or volume  34  is provided in the collar  18 , as by milling, opposite the self-locking link  12 , so as to provide balance, i.e., mechanical stability, at the typical 3,600 rpm maximum operating speed of the spline/saw. The self-locking link  12  is generally configured so as to be responsive to centrifugal force imparted from the rotating spline to and through the collar, a force which readily overcomes the tensioned interface of the link  12  relative to the collar  18 . The link  12  generally includes opposing ends, namely, a spline engaging lobe  36  opposite a free end  38  thereof. As illustrated, the link  12 , more particularly, the spline engaging end  36 , is mechanically united to the collar  18  for pivot motion, i.e., rotation, with respect thereto. More particularly, the spline engaging lobe  36  includes a through-hole  40  for receipt of a fastener  42  which is receivable in an bore  44  of a surface of the collar  18  ( FIG. 6 ), thus defining a pivot axis  46  for the link, an axis substantially parallel to an axis of rotation  48  for the spline  16 .  
         [0023]     The spline engaging lobe  36  advantageously includes an eccentrically configured sidewall or camming surface  50 ( FIGS. 2 &amp; 4 ). As indicated with respect to  FIG. 2 , there is a non-constant or variable radial distance between the pivot axis  46  and the sidewall  50  of the spline engaging lobe  36 , i.e., r 3 &gt;r 2 &gt;r 1 . With such a sidewall configuration, there results a camming interface between the self-locking link  12  vis-a-vis the spline engaging lobe  36 , more particularly, a wedging or progressive locking effect for the spline engaging lobe  36  relative to the spline  16 . Further features of the spline engaging lobe  36  shall be later presented and discussed in relation to  FIGS. 5-7 .  
         [0024]     With regard to the free end  38  of the self-locking link  12 , it is advantageously, but not necessarily, configured so as to be lobe-like. Furthermore, the free end  38  of the link  12  is to have a sufficient area, i.e., mass, so as to outwardly swing with rotation of the spline  16  ( FIG. 4 ). As shown, a crotch  52  delimits the more massive free end lobe  38  from the spline engaging lobe  36 . With higher rpms, the free end  38  of the link  12  progressively travels through an arcuate path, the travel thereof terminating upon a supremely tight interference fit between the spline  16  and the spline engaging lobe  36 , more particularly, the eccentric sidewall  50  thereof.  
         [0025]     Functionally, the self-locking link  12  is pre-tensioned, as will later be described, such that a portion of the spline engaging lobe  36  inwardly extends beyond the inner periphery  22  of the collar  18 , i.e., the perimeter of the inner periphery  22  of the collar  18 , that is to say, the spline conforming periphery  22  of the collar  18  is “interrupted” by a portion of the spline engaging lobe  36 , e.g., the region associated with the r 2- r 3  segment of the eccentric sidewall  50 . This condition or state for the assembly is associated with an assembly  10  “out-of-the-box,” e.g., see the arrangement of  FIG. 5 . As will be later discussed, the link is readily manipulated for increased pre-tensioned axial positioning of a saw blade upon the arbor, or for overcoming a tensioned interface of the saw blade upon the arbor.  
         [0026]     To achieve the “fit” or arrangement of  FIGS. 1 &amp; 2 , the free end  38  of the link  12 , i.e., the major lobe, is radially directed inward by an operator, thereby overcoming the tension associated with the link  12 , so as to clear the spline engaging lobe  36 , i.e., the portion thereof previously described, from the inner periphery  22  of the collar  18 . A stop  54  extends from the surface  20  of the collar  18  (see e.g.,  FIGS. 2 &amp; 3 ) to limit pivoting, i.e., inward travel of the free end  38  of the link  12 , and thus preserve the pre-tensioned condition therefor. With the collar  18  slidingly received upon the spline  16 ,  FIGS. 1 &amp; 2 , release of the free end  38  of the link  12  results in an affixation of the assembly  10  upon the spline  16 ,  FIGS. 3 &amp; 4 , via an initial frictional engagement of the spline engaging lobe  36  of the link  12  with the spline  16 . With such arrangement of elements and associated functionality, preselected, targeted spaced apart saw blade relationships are maintained throughout the blade arrangement process, and initial saw start up, i.e., spline rotation. Proceeding from initial saw start up to full operation, the self-locking link  12  pivots about the pivot axis  46 , more particularly, the free end  38  thereof, under centrifugal force, is outwardly thrust ( FIG. 4 ) with the eccentric sidewall  50  progressively wedging against the rotating spline so as to define an interference fit for the saw relative thereto.  
         [0027]     Referring now generally to  FIGS. 5-7 , the collar  18  preferably, but not necessarily, includes a surface having a cut-out segment  56  for receipt of the self-locking link  12 . Advantageously, such discontinuous surface, opposite the saw blade surface, facilitates close tolerance blade spacing upon the spline, i.e., the thickness of only the collar need be accounted for in the spacing as opposed to the combined thickness of the collar and link. As previously noted, a relief  34  is provided in the collar  18  opposite the link  12 , more particularly, opposite the cut-out segment  56 .  
         [0028]     Referring now particularly to  FIGS. 6 &amp; 7 , the pre-tensioned condition for the link  12  is advantageously, but not necessarily, enabled, as shown, by a hairpin spring  58  disposed between the link  12  and the collar  18 . It is to be understood that other tensioning mechanisms, and accompanying component arrangements, are contemplated.  
         [0029]     As evidenced by  FIGS. 6 &amp; 7 , the tensioning element  58  operatively unites the collar  18  and the link  12 . The tensioning element  58  is secured at one end to the collar  18 , with the remainder thereof essentially housed within a recessed surface  60  of the link. As shown, the recess  62 , which is generally configured to receive a portion of the tensioning element  58 , is adjacent or proximal the through hole  40  of the link  12 , more particularly, the spline engaging lobe  36  thereof. The link fastener  42  further integrates the collar  18 , tensioning element  58 , and link  12  as shown ( FIG. 6 ).  
         [0030]     For installation of the assembly  10 , as previously and briefly discussed in relation to  FIGS. 1-4 , an operator would push down slightly on the camming link  12 , more particularly, the free end thereof  38 , to overcome the slight pressure of the hairpin spring  58 , and slide the saw/collar onto the spline  16 , and thereafter translate same for select positioning thereon. The hairpin spring provides initial tension for presetting the position of the collar. While, for example, holding a pre-cut piece of hardwood against the side of one or two of the saw blade teeth, the operator would slide the next saw collar assembly to the wood, and use the wood as a gauge. As is readily appreciated, it is contemplated and advantageous to utilize a digital setting device so as to provide an exact position, within a few thousandths of an inch. Upon release of the camming link  12 , the hairpin spring  58  pre-tensions the collar  18  for ease of setting, and also prevents drifting when the arbor is started. The operator would continue to set the next or subsequent collars using corresponding blocks of wood until all of the collars are set so as to produce the desired net rips. When the saw is started, centrifugal force causes the camming link to rotate radially, and thereby provide or impart a locking force on the arbor due to the camming surface of the link in engagement therewith. This force will be consistently and simultaneously be placed on all collars because all the cams have substantially the same mass.  
         [0031]     Further advantageous, non-limiting features of the self-locking link  12  include a relieved edge  64  for the eccentric sidewall  50  of the spline engaging lobe  36 , and a cut-out  66  in a portion of the free end  38  of the link  12 ( FIG. 7 ). Inclusion of the relieved edge  64  for the eccentric sidewall  50  prevents burr formation between the adjacent contacting surfaces of the collar  18  and the link  12 , and thus maintains an unencumbered pivot path for the link. Wear issues are further advantageously minimized, as for example via hardening of the link with a melonite®, or equivalent process, which likewise improves the lubricity of the link, and thereby minimizes fretting corrosion.  
         [0032]     As to the cut-out  66  of the free end  38  of the link  12 , it is provided as a “catch” for a work piece, i.e., a link manipulating tool, more particularly, the spline engaging lobe  36  thereof. The release tool, in combination with the cut-out  66  of the free end  38  of the link  12 , is advantageously used to reach between two closely-positioned collars to more firmly pre-lock a saw blade axially upon the arbor, i.e., displace free end of lobe  38  from stop  54 , effectively, resulting in a departure from the arrangement of  FIG. 2 .  
         [0033]     As should be further appreciated, rearranging of saws on the spline requires disabling of the wedged interface of the eccentric sidewall  50  of the spline or arbor engaging lobe  36  from the spline or arbor  16  ( FIG. 4 ). In-as-much as the frictional engagement may be overcome by supplying a force to that portion of the free end  38  of the link  12  extending beyond the periphery of the outer edge of the collar  18 , typical spatial arrangements between saw blades upon the arbor, as previously noted, are not necessarily conducive for delivering a loosening blow. Beyond the contemplated use of a tool to tap upon the free end  38  of the link  12  in furtherance of rotating the link towards the arbor (i.e., more particularly, stop  54 ) and thereby releasing the saw blade from the arbor, the cut-out may further be configured to receive an operative end of a tool for such purpose, i.e., return the link to the arrangement of  FIG. 2  from the arrangement of  FIG. 4 .  
         [0034]     Finally, there are other variations of the subject invention, some of which will become obvious to those skilled in the art. It will be understood that this disclosure, in many respects, is only illustrative. Changes may be made in details, particularly in matters of shape, size, material, and arrangement of parts, as the case may be, without exceeding the scope of the invention.