Abstract:
A device for centering tools, such as saw blades, rotary cutters and the like which are circular and which have bores of different sizes, on processing machines such that they can be positioned about their center axes. The device includes a mount adapted to be attached to such a machine, and a slide coupled to the mount and adapted to move relative to the mount. A first bearing is coupled to the mount, and a second and third bearing are coupled to the slide and mounted for movement on the slide selectively toward or away from the first bearing. The first, second and third bearings are configured to engage the bore of the blade such that the bore is centered on the machine and the blade is rotatable about its center axis.

Description:
This application is a continuation in part of U.S. patent application Ser. No. 09/301,041, filed Apr. 28, 1999, now U.S. Pat. No. 6,298,573. 
    
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
     The present invention relates to a device for centering tools, such as saw blades, rotary cutters and the like which are circular and which have bores of different sizes, on processing machines such that they can be positioned about their center axes. 
     It is well known in the art that cutting tools such as industrial saw blades are provided with center bores (openings) having a variety of sizes. In order to sharpen such tools, it is necessary to position them on machines like grinders such that they are rotatable about their true center axes. This is commonly handled in shops that process (sharpen) such saw blades by providing, with each machine, a rather large quantity of bushings for selective trial in the saw blade to be finished. While this approach is commonly used, it is difficult and time consuming to find the right bushing to center each saw blade brought to the machine. 
     Some machinists have provided rather complex mechanisms comprising three jaws and a mechanism for moving the jaws radially outwardly and inwardly selectively to fit a blade. These mechanisms, however, are rather complex and are difficult to use for a wide range of bore sizes. 
     The device of the present invention is primarily concerned with centering saw blades having different bore sizes on a processing machine. According to other features, characteristics, embodiments and alternatives of the present invention which will become apparent as the description thereof proceeds below, the present invention provides a device for centering tools, such as saw blades, rotary cutters and the like which are circular and which have bores of different sizes, on processing machines such that they can be positioned about their center axes. 
     According to the illustrative embodiment of the disclosure, a centering device is provided for centering a circular cutting tool on a processing machine such as a saw blade grinder. The device comprises a mount adapted to be attached to the machine, a slide coupled to the mount and configured for movement relative to the mount, a first bearing mounted on the mount, and a second and a third bearing mounted on the slide for movement with the slide selectively toward and away from the first bearing. The slide and mount cooperate to support the tool and to present the tool to a processing element. The first, second and third bearings are engagable with the bore of the tool to cause the tool to be centered on the machine when the second and third bearings are moved from the first bearing securely pulling the tool bore against the first, second and third bearings, whereby the tool is then rotatable about its center axis. Each tooth of the saw blade can then be presented to a grinding wheel or other cutting device such that each tooth will be finished relative to the true center of the blade. An adjuster is also provided that is configured to move the slide selectively toward and away from the first bearing mounted on the mount. 
     A method of centering a tool on a machine is further disclosed. The method comprises the steps of providing a mount configured for coupling with a processing machine, providing a bearing on the mount, and providing a slide having a first row and a second row of holes. The slide is configured to move relative to the mount. The method further comprises the steps of positioning the tool on the mount and slide such that the bore engages the bearing and at least one hole from each row of holes is visible through the bore, placing a pin carrying a second bearing in an outermost visible hole of the first row, placing a pin carrying a third bearing in an outermost visible hole of the second row, and moving the slide relative to the mount such that the first, second, and third bearings engage and hold the bore of the tool. 
     Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments exemplifying the best mode of carrying out the invention as presently perceived. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The present invention will be described hereafter with reference to the attached drawings which are given as non-limiting examples only, in which: 
     FIG. 1 is a perspective assembled view of a centering device according to the present invention, showing a mount having a movable slide coupled therewith, the mount and slide being configured to carry a blade and support the blade for rotational movement about three bearings; 
     FIG. 2 is a perspective view similar to FIG. 1 showing the blade mounted on the mount and slide, the mount carrying a first bearing and the slide carrying second and third bearings; 
     FIG. 3 is a top view of the centering device of FIGS. 1 and 2; 
     FIG. 4 is an assembly view of the centering device, showing the device being mounted to rods which are used in presenting the blade to be processed; 
     FIG. 5 is a top view similar to that of FIG. 3, showing the centering device turned 180 degrees to accommodate a differently sized blade; 
     FIG. 6 is a view taken along the line  6 — 6  of FIG. 3, wherein the centering device is mounted such that a rod engages the inner-most angled recess of the bottom of the mount; and 
     FIG. 7 is a view taken along the line  7 — 7  of FIG. 5, wherein the centering device has been turned 180 degrees from the view of FIG. 6, and the centering device has been mounted such that a rod engages the outer-most angled recess of the bottom of the mount. 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates a preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to centering devices, such as those disclosed in U.S. patent application Ser. No. 09/301,041, incorporated herein by reference. 
     The present invention is directed to a centering device  10  which is proportioned and designed to be mounted on a machine for processing circular tools such as saw blades having center bores. Such a machine may be, for example, a grinder used to sharpen industrial saw blades. Such grinders typically comprise a support upon which a saw blade is placed and indexed about its axis on a bushing such that each tooth can be sharpened or otherwise finished. Such machines typically have a single upwardly or outwardly extending bearing post although industrial saw blades are provided with a wide variety of bore diameters ranging from, for example, 1 inch up to 5.5 inches in diameter. Each such machine is typically provided with a plurality of bushings having an inner diameter which will fit the bearing post on the machine and a wide range of outer diameters which will fit typical bore diameters in saw blades. It will be appreciated that the operator of the machine must sort through a multitude of bushings to find an appropriate bushing. Quite often, for individual saw blades, a separate bushing will have to be made at some considerable time and expense. It will also be appreciated that some machines have horizontal (upwardly facing) work surfaces such that the blades are horizontally oriented. Conversely, other machines have vertically (laterally facing) work surfaces such that the blades are vertically oriented. 
     Centering device  10 , shown in FIGS. 1-7, is provided to replace the multitude of bushings. Centering device  10  engages a blade  12  at its bore  14 , as shown in FIGS. 1-3. Centering device  10  includes a mount  16  configured for mounting on a machine, such as a grinding machine. Illustratively, centering device  10  is configured for mounting on an Akemat grinding machine, available from AKE Knebel, of Balingen, Germany. It should be understood that the disclosed centering device can be configured for other machines and particularly saw grinding machines by modifying the bottom of the mount to couple with such machine accordingly. 
     Centering device  10  is shown in FIG. 1 positioned to receive a blade  12  at its bore  14  such that blade  12  is mounted on centering device  10  as shown in FIGS. 2-3. Bore  14  may be dimensioned substantially as shown in FIG. 3, or may be a smaller sized bore  14 ′ or a larger sized bore  14 ″, as shown in phantom in FIG.  3 . 
     Illustratively, an Akemat grinding machine includes a pair of spaced apart, parallel rods  11 ,  13 , onto which mount  16  is mounted, as shown in FIGS. 1,  3 , and  4 . As illustrated in assembly view in FIG. 4, centering device  10  includes a plate  98  having a pair of dowel pins  100  for insertion into holes (not shown) bored in bottom  102  of mount  16 . A fastener  104  is also provided and inserted through aperture  106  formed in plate  98 . Fastener  104  threads into a counter bore hole (not shown) in bottom  102  of mount  16 , thereby securing rods  11 ,  13  between plate  98  and bottom  102 , as shown in FIGS. 1,  3 , and  5 - 7 . 
     Mount  16  includes guide walls  22 ,  24 , and a nose  26 , as shown in FIGS. 1 and 4. Walls  22 ,  24  position and guide a slide  18  for movement relative to mount  16  in the directions indicated by arrows  28 . Slide  18  is configured to move relative to mount  16 , and surface  20  of slide  18  becomes a part of the support surface upon which blade  12  rests. Nose  26  extends from mount  16  and bounds one end of the sliding movement of slide  18 . Sliding movement of slide  18  is bounded on the other end by retainer  30 , which is secured to mount  16  with fasteners  32 . Retainer  30  defines a threaded aperture  39 . 
     Sleeve  35  of adjuster  34  mates with aperture  39  of retainer  30 , as shown in exploded view in FIG.  4 . Threaded end  36  of adjuster  34  is further configured to mate with threaded bore  38  of slide  18 . When sleeve  35  is mated with retainer  30  and threaded end  36  is mated with threaded bore  38 , adjuster  34  controls the positioning of slide  18  relative to mount  16 . 
     Illustratively, adjuster  34  is a pneumatic piston for controlling the positioning of slide  18  relative to mount  16  in response to a pressurized gas. Nozzle  37  of adjuster  34  is pneumatically coupled to a pressurized gas source (not shown), which operates to pressurize piston  34 , thereby axially extending threaded end  36  away from adjuster  34 . Piston  34  can also be depressurized, such that threaded end  36  retracts axially into adjuster  34 . Such axial extension and retraction movement causes slide  18  to move respectively either away from or toward retainer  30 , as indicated by arrows  28 . Because retainer  30  is in turn supported by mount  16 , the extension and retraction movement causes slide  18  to move relative to mount  16 . 
     A fixed dowel pin  70  is mounted on top surface  72  of nose  26 . Illustratively, fixed pin  70  has a threaded shaft  74  which engages threaded hole  76 . Shaft  74  of fixed pin  70  is inserted through washer  86  and bearing  88  prior to engagement with threaded hole  76 , as shown in FIG.  4 . 
     Adjustable dowel pins  42 ,  44  cooperate with fixed dowel pin  70  to cause bearings  88 ,  92 ,  96  to engage an inner surface  78  of bore  14  of blade  12 , as shown in FIGS. 1-3 and  5 . Adjustable dowel pins are selectively positioned in holes bored in slide  18  such that bearings  92 ,  96 , carried by dowel pins  42 ,  44 , respectively, are sufficiently spaced from fixed pin  70  to engage the inner surface  78  of whatever diameter of bore  14  is provided. Dowel pin  42  is selectively positioned in one of dowel holes  46 ,  48 ,  50 ,  52 ,  54 ,  56 , while dowel pin  44  is selectively positioned in one of corresponding dowel holes  58 ,  60 ,  62 ,  64 ,  66 ,  68 . Although the illustrated embodiment utilizes two adjustable dowel pins  42 ,  44 , it is also within the scope of the disclosure to utilize only one adjustable dowel pin (not shown), or any other number of adjustable dowel pins cooperating with bearings. 
     Upon being mounted, centering device  10  is operated substantially as follows. Slide  18  is moved away from retainer  30  by actuating adjuster  34  with pneumatic pressure directed through nozzle  37 . As slide  18  moves away from retainer  30 , it carries adjustable dowel pins  42 ,  44  toward fixed dowel pin  70 . Blade  12  is positioned to lie on top surface  20  of slide  18 , and simultaneously on top surface  72  of nose  26  such that bearing  88  of fixed dowel pin  70  is proximate to or engaging inner surface  78  of bore  14 , substantially as shown in FIGS. 2-3. 
     Adjustable dowel pin  42  is selectively inserted in one of dowel holes  46 ,  48 ,  50 ,  52 ,  54 ,  56 , and adjustable dowel pin  44  is selectively inserted in one of corresponding dowel holes  58 ,  60 ,  62 ,  64 ,  66 ,  68  such that dowel pins  42 ,  44  move to engage bore  14  when adjuster  34  moves slide  18  back toward retainer  30 . Adjuster  34  moves slide  18  toward retainer  30  by the application of negative pneumatic pressure through nozzle  37 . 
     For example, if bore  14  is dimensioned such that dowel pin  42  is ideally placed in dowel hole  50 , as is shown in FIG. 3, dowel pin  44  is respectively placed in dowel hole  62  such that bearings  92 ,  96  are positioned to simultaneously exert pressure on the inner surface  78  of bore  14  when slide  18  is tightened via adjuster  34  such that bore  14  is in contact with bearing  88  of fixed pin  70  and bearings  92 ,  96  of adjustable pins  42 ,  44 . 
     Various radii for bore  14 ,  14 ′, and  14 ″ are shown in FIG.  3 . If bore  14  is dimensioned as shown, centerpoint  80  is positioned such that inner surface  78  contacts bearing  88  of fixed pin  70 , while adjustable pins  42 ,  44  are positioned in dowel holes  50  and  62 , respectively, such that bearings  92 ,  96  are in contact with inner surface  78  when adjuster  34  is tightened. Similarly, a smaller radius for bore  14 ′ (shown in dotted lines) is accommodated by placing adjustable pins  42 ,  44  in dowel holes  46 ,  58 , respectively and positioning centerpoint  84  as shown. Further illustratively, a larger radius for bore  14 ″ is accommodated by placing adjustable pins  42 ,  44  is dowel holes  56 ,  68 , respectively, and positioning centerpoint  82  as shown in FIG.  12 . 
     Blade  12  is mounted and ready for use when adjuster  34  has moved slide  18  such that the respective bearings  88 ,  92 ,  96  on fixed pin  70  and adjustable pins  42 ,  44  engage inner surface  78  of bore  14 , thereby holding blade  12  in position, as shown in FIG.  2 . 
     Illustratively, blade  12  is presented to the Akemat machine in a fashion that allows blade  12  to rotate about its centerpoint  80  by rolling contact with bearings  88 ,  92 ,  96 . As blade  12  rotates, each of bearings  88 ,  92 ,  96  rotates about its associated axial pin  70 ,  42 ,  44 . Blade  12  is moved with an “index finger” which is part of the Akemat machine. 
     Both large and small diameter blades can be accommodated by the manner in which mount  16  is mounted on rods  11 ,  13 . For illustrative purposes, the following description assumes that a blade  12  is processed at the right side of each of the pages of FIGS. 1-5. Large diameter blades are accommodated when mount  16  is mounted such that nose  26  points toward the left side of the page (away from the processing side), as shown in FIGS. 1-4 and  6 . In such a configuration, rod  11  is positioned in angled recess or channel  108  and rod  13  is positioned under bottom  102  of mount  16 , as shown in FIG.  6 . Such a configuration requires fastener  104  to engage bored hole  110 , which can be seen in FIG.  4 . The offset alignment is required by the Akemat machine in order to have proper processing. 
     Smaller diameter blades can be accommodated by mounting mount  16  such that nose  26  points toward the right side of the page (toward the processing side), as shown in FIGS. 5 and 7. When nose  26  is turned toward the processing side, fastener  104  is threaded into bored hole  112 , which can be seen in FIG. 4, in order to accommodate the alignment required by the illustrative Akemat machine. Furthermore, in order to hold mount  16  in alignment, rod  13  is positioned in angled recess  109  and rod  11  is positioned under bottom  102 . 
     Although the present invention has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the present invention and various changes and modifications may be made to adapt the various uses and characteristics without departing from the spirit and scope of the present invention as set forth in the following claims.