Patent Abstract:
An air jet containing blade guide for stabilizing a band saw blade or a circular saw blade of a saw mill and guide blocks or inserts for a saw blade guide are disclosed. The inserts can be removably fastened to a blade guide by means of cap screws preferably containing a hex socket for tightening and loosening the screws with a hex wrench. Cap screw holes formed in the inserts contain recessed countersinks for recessing the heads of the cap screws below a blade opposing surface of the inserts when disposed in an operative position of a blade guide in a saw mill. The inserts can be constructed of brass or aluminum bronze which is softer than the blade being stabilized thereby to avoid undue blade damage but which are hard enough to provide good wearability and heat dissipation as against periodic blade impacts. The blade guide disclosed contains a threaded air inlet port and an air passageway extended between the port and a side of the guide facing a work piece when the guide is operatively positioned in the mill to permit high pressure air supplied to the input port to be directed toward the kerf of the work piece to clean the latter of saw dust.

Full Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to blade guides and blocks or inserts used on such guides to stabilize a circular saw blade or band saw blade of a saw mill. More specifically, this invention relates to an air jet containing blade guide for use in cleaning the kerf of a work piece and to inserts for saw blade guides. 
     Broadly speaking, blade guides have long been known and used for stabilizing both band saw and circular saw blades in saw mills. While some early saw blade guides, such as those disclosed in U.S. Pat. No. 425,105 to R. McChesney issued on Apr. 8, 1890, use inserts or blocks which are removably fastened to the saw blade guide by means of threaded fasteners, none of these prior art inserts use cap screws for holding the inserts in place which are countersunk within the insert which are threadably inserted onto and removed from a blade opposing surface of the insert and guide surface upon which the insert is mounted. Moreover, none of the prior art inserts which are mounted on the blade guides are constructed of aluminum brass or aluminum bronze. Further, none of the prior art guides upon which inserts are mounted contain air passageways which open toward the kerf of the work piece being formed in the mill in which the guide and insert is mounted therein. 
     By means of my invention, these and other difficulties encountered using prior art guides and inserts are substantially eliminated. 
     SUMMARY OF THE INVENTION 
     It is an object of my invention to provide a novel metal insert for a blade guide of a saw mill. 
     It is a further object of my invention to provide a novel metal insert for a blade guide which is removably attachable to the guide. 
     It is a further object of my invention to provide a novel metal insert for a blade guide which is constructed of aluminum bronze or brass. 
     It is another object of my invention to provide a novel air jet containing blade guide for either a band or circular saw mill. 
     Briefly, in accordance with my invention there is provided a metal insert for a saw blade guide for stabilizing a saw blade. The insert comprises a block of material attachable to a saw blade guide. The material is selected from the group consisting essentially of aluminum-copper alloys of bronze and of brass which have a Brinell Hardness Number of between about 110 to 321. 
     Further, in accordance with my invention, there is provided a blade guide for mounting a blade stabilizing insert thereon. The guide includes a base plate and a block disposed on the base plate and recessed from a free end of the base plate. The block defines an interiorly threaded blind hold forming an air inlet port which opens onto a surface of the block for attachment thereto of an exteriorly threaded air outlet connector of a remote high pressure air source. The block also defines a hollow air passageway extending from the air inlet port to an opening on a side of the block which faces a work piece when the guide is disposed in an operative position in a saw mill. The opening is disposed at about the same level as that of a saw blade being stabilized by the guide when the latter is operatively positioned. 
     These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and attached drawings upon which, by way of example, only the preferred embodiments of my invention are illustrated. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an exploded perspective view of a saw blade guide assembly, thus illustrating a preferred embodiment of my invention. 
     FIGS. 2-3 show a front elevation view and a top plan view, respectively, of a novel angle type blade guide containing a novel metal insert, the guide and insert being components of the assembly of FIG.  1 . 
     FIG. 4 shows a side elevation view of the angle guide of FIGS. 1-3 together with inserts and fragments of a straight guide and of a band saw blade the same as shown in FIG. 1 except now being in operative positions relative to one another. 
     FIGS. 5-6 show a side elevation view and a top plan view, respectively, of a novel saw blade guide which is an alternative to the angle guide of FIGS. 1-4, thus illustrating another important embodiment of my invention. 
     FIG. 7 shows a perspective view of the blade guide of FIGS. 5-6 as used in stabilizing a circular saw blade. 
     FIGS. 8-9 show a plan view and a longitudinal elevation view, respectively, of one of the novel metal inserts of FIGS. 1-4. 
     FIGS. 10-11 show a plan view and a longitudinal elevation view, respectively, of an alternative form of metal insert that can be used in place of each of the inserts shown in FIGS. 1-4 and  8 - 9 . 
     FIG. 12 shows a perspective view of another alternative form of metal insert that can be used in individually or in multiples in place of each of the inserts as shown in FIGS.  1  and  4 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawing figures and, in particular, to FIGS. 1 and 4 there is shown, in a preferred embodiment of my invention, an improved blade guide assembly, generally designated  10 , for stabilizing a band saw blade  12  having cutting teeth  13  of a conventional band saw mill assembly, not shown, to limit or effectively prevent lateral vibration, bending or dishing of the blade during sawing operations. At the outset, it will be understood that the assembly  10  can also be used to stabilize a circular saw blade of a circular saw mill such as is illustrated in FIG.  7  and as later more fully explained. The assembly  10  includes a conventional straight guide  14 , located adjacent one broad side of the blade  12  and an improved angle guide, generally designated  16  (See also FIGS. 2-3) having a base plate  18  which is located adjacent the other broad side of the blade. The guides  14  and  16  may be made of any suitable high yield strength material such as, for example, AISI C1018 cold drawn steel or ASTM A-36 hot rolled steel. A novel pair of blade guide blocks or inserts  20 ,  22  (See also FIGS. 2-3) is removably secured to the blade opposing base plate  18  of the angle guide  16  and to a blade opposing surface  24  (See FIG. 1) of the straight guide  14  by means of threaded fasteners  26 . The fasteners  26  are preferably flat head, cap screws, each of which contains a cone shaped head or cap  29  having a hex socket  27  in the cap. The guides  14  and  16  are conventionally attached, adjustably, to the saw mill assembly in the usual, well known manner, as, for example, by means of bolts  28  located in elongated slots  30  and  32  of the guides,  14  and  16 , respectively. The slot  32  (FIGS. 1-3) is located in a back plate  34  of the angle guide  16 , the base plate  18  and back plate  34  of which adjoin one another to form a generally L-shaped configuration and extend perpendicularly from one another. 
     The novel feature of the improved angle guide  16  as shown in FIGS. 1-4 comprises an elongated block member  36  which is formed in and along the corner in which the plates  18  and  34  intersect and rises from the base plate along the back plate to a level which is above the level of the blade  12  as it passes between the inserts  20  and  22  when the guide  16  is in its operative position in the saw mill, as best seen in FIG.  4 . The block member  36  contains an interiorally threaded blind hole or socket forming an air inlet port  38  located near one side of the block member, which port opens upwardly, as viewed, onto an upper surface  40  thereof. The member  36  also contains a hollow passageway  42  (See FIGS. 1-3) which extends parallel to and is spaced from the back edge of the blade  12  to an opening or air outlet port  44  located on a side  46  (FIGS. 2-4) of the guide  16  which faces a work piece, not shown, when the guide is in its operative position in the mill. When the guide  16  is in its operative position, it is important that the opening  44  be disposed very close to the same level as that of the blade  12  as seen in FIG.  4 . The socket  38  can thus be fitted in an air tight manner with a conventional exteriorly threaded connector  45  of an air hose  47  (FIG. 1 only) leading to an externally located high pressure air source such that high pressure air can be directed into the air inlet port  38 , thence through the passageway  42  and out of the opening  44  close to and directed alongside the back edge of the blade  12  and against a work piece being operated on by the mill to blow saw dust from the kerf formed by the blade  12 . 
     Preferably, the block  36  forms a second step in conjunction with a first step  48  (See FIGS.  1 - 4 ), the first step being recessed sufficiently from an outer edge of the base plate  18  to provide sufficient space on which to mount the insert  22  on the base plate. The raised first step  48  thus forms a backing wall for the insert  22  but allows the blade  12  to overlie an upper surface  50  thereof when the angle guide  16  is in its operative position in the mill. Preferably, the block or step  36 , step  48 , base plate  18  and back plate  34  are integrally formed as a single unitary angle blade guide component. 
     The blade guide assembly  10  of FIGS. 1 and 4 can also be used to stabilize a conventional circular saw blade as well as a band saw blade such as the blade  12 . Moreover, the air inlet port  38  and passageway  42  with opening  44  can also be used to clean the kerf of a work piece being operated on by such a circular saw blade. To use the assembly  10  with a circular saw, the angle guide  16  should be arranged so that the vertical side  46  of the guide  16 , as viewed, faces a peripheral portion of the teeth of the circular saw blade as they enter the work piece. Assuming the blade  12  of FIG. 4 is an outer peripheral wedge portion of a circular saw blade, the cutting teeth  13  of the blade would then be on the left edge of the blade  12 , as viewed, opposing but spaced from the block  36 , rather than being on the right edge as in the band saw of the example previously discussed. Further, the blade guide assembly  10 , including the straight guide  14  with its insert  20  and the opposing angle guide  16  with its insert  22 , should be disposed in the circular saw mill at an angle of from about 15 to 25 degrees from the work piece as measured in a plane containing the saw blade such that, as the circular saw rotates, a given tooth of the blade will rotate through the assembly  10  about 15 to 25 degrees of arc before it rotates into a cutting position against the work piece. 
     Referring now to FIGS. 5-7, there is shown, in another important embodiment of my invention, a saw blade guide assembly, generally designated  52 , which, as in the case of the assembly  10  of the previous example, can also be used to stabilize the blade of either a band or a circular saw. In the present example, the assembly  52  is shown in use with a circular saw blade  54 , a fragment of which is shown, schematically, in FIG. 5 with saw teeth assumed on and around an outer peripheral portion thereof. The assembly  52  includes an air jet saw blade guide, generally designated  56 , and a straight guide  58  (FIG. 5 only), which may be similar to the straight guide  14  of the previous example. The guide  56  can also be used in place of the angle guide  16  of FIGS. 1-4 and includes a base plate  60  containing a block  62  thereon. The block  62  is recessed sufficiently from an outer free edge of the base plate  60  to permit an insert  64  to be removably mounted thereon. A similar insert  64  (FIG. 5 only) is removably attached to the straight guide  58 . The block  62  extends above the base plate  60  to a level which is above the blade  54  as best seen in FIG. 5 to permit placement through the block of a hollow air passageway  66  (See FIG. 6) between an interiorly threaded blind hole, which functions as a high pressure air inlet port  68 , and an opening  70  on a side of the block  62 . The opening  70  functions as an air outlet port so as to expel high pressure air toward a work piece  72  (See FIG. 7) being operated upon by the saw blade  54 . The expelled air steam should be aligned so as to be directed tangent to the periphery of the blade teeth  54  entering the work piece. In this manner, the guide  56  operates to aid in stabilizing the blade  54  and also to provide a high pressure air steam to clean the kerf in the work piece  72  formed by the blade. The block  62  should be formed so as to be sufficiently thick to permit the back of the guide  56  to be securely attached to a conventional bolster  74  on the saw mill containing the blade  54  as by means of suitable threaded members  76 . The inserts  64  may be of any suitable type but are preferably of the same type as those shown at  20  and  22  of the previous example. As in the previous example, the inserts  64  are preferably removably secured to the base plate  60  by means of suitable flat head, socket head, cap screws  78 . As in the previous example, it is important that the surface of the head  80  (See FIG. 5) of each of the screws  78  be disposed in a countersink in an upper surface portion of the inserts  64  so as to be recessed and spaced below the blade opposing surface of the insert. 
     Referring now also to FIGS. 8-9 the novel inserts  20 ,  22  of the assembly  10  of FIG. 14 are shown in detail. These inserts  20 ,  22  are also of the same type shown in the example of FIGS. 5-7 as at  64 . They are constructed of copper aluminum alloy (bronze or brass). They must have sufficient abrasion resistance, heat dissipation capability and wearability to be of practical use as inserts for band saw and circular saw guides in that they will also have a reasonable service life. However, they must not be so hard that they will damage a rapidly moving blade being stabilized thereby when impacted by the blade, as will occur periodically during normal use. When using a continuous cast aluminum bronze insert, I have found that such a material classified by Specification ASTM B-505, Grades 952-959 will meet these requirements. Similarly, when using an individually cast aluminum bronze insert, I have found that such a material classified as ASTM B-148, Grades 952-959 will also meet these requirements. The Brinell Hardness Number of such aluminum bronze or brass inserts, as measured under a 3,000 kg load, should be within the range of about 110 to 321. For a BHN of less than about 110, I find that the insert lacks sufficient wearability for practical use and for a BHN above about 321 the insert will ordinarily be harder than the blade being stabilized wherein blade damage can be expected upon impact with the insert. The insert of FIGS. 8-9, as also shown in the assembly  10  of FIGS. 1-4 and, of which are the same type as used in the assembly  52  of FIG. 5, have rounded edges  82  on opposite ends of blade opposing surface portions thereof, which ends extend transversely relative to movement of the band saw blade  12  of FIGS.  1  and  4 ). In the alternative, FIGS. 10-11 show the same type of aluminum bronze or brass insert  84  as those at  20 ,  22  of FIGS. 8-9 except that this insert contains a pair of beveled edges  86  on opposite ends of a blade opposing surface portion. Here, again, the beveled edges  86  extend transversely with respect to the direction of band saw blade movement. In each of the inserts  22  and  84  of FIGS. 8-9 and  84  of FIGS. 10-11, respectively, two untapped screw holes  88  are formed in a base portion thereof with a recessed frustroconical countersunk portion  90  formed above the screw hole  88 , as viewed, so that a cap screw, such as is shown at  26  in FIGS. 1 and 4, can be inserted therein to a level below an upper surface  91  of the insert. I recommend that the cap screws  26 , as shown in the example of FIGS. 1-4 and as shown at  78  in the example of FIGS. 5-6, be preferably of the hex socket type for use of a standard hex wrench to secure and loosen the same from its corresponding guide, although other types of commonly known cap screws could be employed wherein a standard tool such as a screw driver could be used to secure and remove the same from its guide. 
     Referring now to FIG. 12, there is shown a blade guide insert, generally designated  92 , which may be made of tungsten carbide, which is the material from which conventional saw blade guide inserts are commonly made. However, conventional tungsten carbide inserts are permanently attached to blade guides by means of silver soldering, brazing or other fusion processes. In this example, I form a recessed countersunk cap screw hole  94  through the insert  92  so that it may be secured in place on its saw blade guide by cap screws, preferably of the same type as shown at  26  in FIGS. 1 and 4 and at  78  in FIGS. 5-6 and as explained in the previous examples. Here, as in the previous examples, the cap screw hole  94  should be formed so that the countersink is recessed below the level of the blade opposing surface  96  of the insert  92  so that the head of the cap screw will not be impacted by the saw blade when the latter impacts the surface  96  of the relatively softer tungsten carbide material. 
     Although the present invention has been illustrated and described herein with respect to certain preferred embodiments, it is not intended that this patent should be limited in scope and coverage by such details other than as specifically set forth in the following claims.

Technology Classification (CPC): 8