|Publication number||US3754493 A|
|Publication date||Aug 28, 1973|
|Filing date||Dec 10, 1971|
|Priority date||Dec 10, 1971|
|Publication number||US 3754493 A, US 3754493A, US-A-3754493, US3754493 A, US3754493A|
|Inventors||Benney H, Niehaus E|
|Original Assignee||Rockwell Mfg Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (47), Classifications (7), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent [191 Niehaus et a1.
[ CIRCULAR SAW BLADE GUARD  Inventors: Edward J. Nlehaus; Barry D.
Benney, both of Tupelo, Miss.
 Assignee: Rockwell Manufacturing Co.,
 Filed: Dec. 10, 1971  Appl. No.: 206,630
 U.S. Cl 83/478, 144/251 R, 83/508.2  Int. Cl. 827g 19/02  Field of Search 143/159 J, 159 T,
Primary ExaminerDonald R. Schran Attorney-William A. Strauch, .1. Matthews Neale et ABSTRACT A see through plastic U-shaped circular saw blade 1 Aug. 28, 1973 guard and kerf splitter assembly wherein the guard is pivotally swingably mounted on the kerf splitter through a relatively short inverted U-shaped link pivoted at one end in straddling relation to the kerf splitter with the web at the one end notched out to dispose the notch end wall to engage the upper edge of the kerf splitter and limit its upward and rearward pivotal movement to maintain the link and guard pivoted at the other end in straddling relation to the link within the upper foreward segment of the pivotal path of the link at all times to assure weight biased movement toward the saw table and guarding position. The kerf splitter is a plate of generally C-shaped configuration having attachment bolt passages in the foreward and rear ends of the lower arm to provide at least one attachment bolt beneath and foreward of the rear end of the table in a relatively inaccessible position when installed to prevent ready removal by the operator. The respective pivot connections include pivot pins fixedly connected to the link and fixedly connected to the guard respectively by end mounted press fitted washers and cap nuts to prevent ready disassembly of the pivot connections and removal of the link or guard. The assembly provides a non-removable safety guard.
14 Claims, 6 Drawing Figures PATENTEB AUG 28 i973 SHEET 1 0? 3 CIRCULAR sAw BLADE GUARD BACKGROUND OF THE INVENTION The present invention relates to blade guard assemblies for motor driven, table type, circular saws in which workpieces supported on the table workpiece support surface are hand fed into a high speed rotating saw blade which protrudes through a narrow blade passage formed in the table usually in centered relation to the side edges of the table. In such saws, the high speed rotating blade is a source of continuous danger to the operators and shop personnel whenever the saw is operating and many serious, even maiming injuries have resulted due to the carelessness of operators and shop personnel, particularly where no safety guards are provided, or ineffective safety guards typical of the prior art have been provided.
Ineffectiveness of the prior art safety guards provided results from several factors in the guard structures heretofore provided. One of the principal factors contributing to ineffectiveness has been the provision of guard structures which interfere with clear visibility of the saw blade during use and are so constructed that they may be readily removed or swung to an inoperative position by a seasoned operator who, because of an exaggerated sense of operating skill or his familiarity due to day-to-day use of such saws, discounts the imminent danger. A further contributing factor has been the flimsy linkage systems provided to mount the guard for its necessary rising and falling movement as the workpiece is fed to the sac blade or as the angular relative adjustment of the blade and table are effected to make bevel cuts.
Typical examples of such prior art guard assemblies are shown in U.S. Pat. Nos. 2,352,235 to H.E. Tautz, 2,623,555 to WA. Eschenburg and 2,787,305 to T.A. Hess et al. (impairing visibility of the blade and readily swingable to an inoperative position depending at the back of the table). I
Efforts to overcome these deficiencies have been made by providing (1) transparent guards as shown in U.S. Pat. Nos. 1,240,430 to P. Erickson, 2,876,810 to J.M. Peterson et al. and 3,105,530 to R.E. Peterson et al.; (2) a centrally pivoted guard as shown in U.S. Pat. No. 2,754,857 to HA. Joslin; (3) a shortened side plate as shown in U.S. Pat. No. 2,786,496 to WA. Eschenberg; (4) swing links internally of the guard mounted on a kerf splitter to limit movement of the guard as shown in U.S. Pat. No. 1,496,212 to S. French and 2,593,596 to G.V. Alson; and (5) a saw guard engageable with a portion of the kerf splitter to limit upward movement as shown by U.S. Pat. No. 1,381,612 to GA. Anderson. None of these efforts, however, provide a wholly satisfactory guard or an inexpensive reliable structure which adequately prevents the operator from readily removing the guard or swinging it to an inoperative position.
SUMMARY OF THE INVENTION The present invention has for its principal object the provision of a safety guard assembly for a circular table saw non-removably mounted on the kerf splitter which is fixedly secured through a mounting bracket at a relatively inaccessible point beneath and inwardly 0f the rear table edge to maintain a position in The plane of rotation of the saw blade in all angularly adjusted positions of the saw blade relative to the table of the saw.
A further object of the present invention resides in providing a blade guard assembly according to the principle object with a blade guard supporting link providing respective end pivotal connections to the kerf splitter and blade guard designed to resist lateral shifting movement of the link and guard relative to the kerf splitter and to limit pivotal movement of the guard between a normal position in which the guard is supported by the work support surface of the table in straddling relation to the blade passage and a limit position, determined by the supporting link which will prevent the blade guard from being swung to an inoperate position.
A further object of the present invention resides in the provision of a rigid metal, guard supporting link of inverted channel shaped configuration in cross section provided at its opposite ends with coaxially aligned, laterally spaced passages and an encompassing blade guard of inverted channel spaped configuration formed in the area of its pivotal connection to the guard supporting link with inwardly thickened wall portions laterally dimensioned to provide area bearing contact with the outer faces of the dependent link sidewalls to thereby eliminate side play between the pivotally related blade guard and supporting link and coaxially through apertured to provide opposed pivot pin mounting openings to press fittingly receive a pivot pin thereby relegating pivotal wear to the link passages and the portions of the pivot pin cooperating therewith.
Another object of the present invention resides in providing the pivot pin of the preceding object in the form of a headed pin having a shank of a length greater than the cross-sectional width of the blade guard whereby the shank end remote from the head will protrude beyond the outer side face of one guard sidewall when the head is seated against the other sidewall and providing the projecting shank end with a press fitted cap nut seated against the one guard sidewall thereby preventing ready removal of the blade guard.
A still further object of the present invention resides in providing the guard supporting link of the previous object with a pivotal connection to the kerf splitter in the form of a sleeve bushing fixedly supported in a through passage in the kerf splitter with its opposite ends projecting from the opposite faces of the kerf splitter sufficiently to fit between and have bearing contact with the opposite link sidewalls and a pivot pin dimensioned have a journalled fit in the sleeve bushing with its opposite ends pressure fitted into and protruding beyond the coaxially aligned link passages to receive in press fitted engage spring washers bearing on the outer sidewall faces of the link thereby relegating pivotal wear to the bushing and the portion of the pivot pin cooperating therewith and preventing ready removal of the link.
BRIEF DESCRIPTION OF THE DRAWINGS Further objects of the invention will appear from the following description and appended claims when read in conjunction with the accompanying drawings wherein:
FIG. 1 is a side elevational view of a table type circular saw illustrating the blade guard and kerf splitter assembly of the present invention in operative mounted position;
FIG. 2 is an enlarged sectional view taken substantially on line 2-2 of FIG. 1 to illustrate the details of the pivotal connection provided to non-removably mount the blade guard support link and anti-kickback fingers on the kerf splitter;
FIG. 3 is a plan view of the blade guard supporting link employed to mount the blade guard on the kerf splitter;
FIG. 4 is a plan view of the blade guard;
FIG. 5 is an enlarged sectional view taken substantially on line 3-3 of FIG. 1 illustrating the details of the pivotal connection provided to non-removably mount the blade guard to the pivot pin joumalled in the blade guard supporting link; and
FIG. 6 is a rear end view of the guard member show ing the kerf splitter in dot-dash lines to illustrate the bearing engagement of the rear end of the guard member and kerf splitter in its normal guarding position in contact with the saw table.
DESCRIPTION OF THE PREFERRED EMBODIMENT With continued reference to the drawings wherein the same reference numerals are employed throughout the several views to indicate the same parts, the blade guard and splitter assembly of this invention designated by numeral 10 is shown applied to a tilting arbor table saw 11 of the type shown and described in U.S. Pat. No. 3,581,784 issued June 1, l97l to Edward C. Warrick et al. Saw 11 comprises a support base and cabinet 12 fixedly mounting a work support table 13 provided with dependent front and rear trunnions 14 (the rear trunnion only being illustrated) supporting a tilt bracket 15 mounting a drive motor, a blade arbor and drive means including a saw blade 16 arranged to project upwardly through the blade opening conventionally provided in table 13 by a slotted insert plate 17. Bracket 15 in the illustrated saw also carries the depth of cut and tilt controls (not shown) for raising and lowering the blade relatively to the table and tilting the blade relatively to the table, such controls being operable as disclosed in the aforesaid patent by operation of the respective hand wheels 18 and 19 and clamp lever 21.
The blade guard and splitter assembly 10 is in the form of unitary assembly as will be hereinafter described in detail and is fixedly secured to the end face of movable tilt bracket 15 through a mounting bracket 22 bolted to bracket I5 by bolt 23 and which is presently provided on some saws to mount existing splitters. As best seen in FIG. 1, the bolted end of bracket 22 lies within the rear cabinet wall 24 which is slotted at 25 through its upper edge to permit its assembly and removal after bracket 22 is bolted to bracket 15 and the dependent hooked shaped mounting arm 26 of blade guard and kerf splitter assembly 10, is bolted at 27 and 27' to bracket 22. It follows, therefore, that once rear cabinet wall 24 is in place bolts 23 and 27 are not readily accessible to an operator who may decide to remove the blade guard and splitter assembly from bracket 15. It also will be appreciated that mounting bracket 22 adapts the blade guard and splitter assembly 10 for ready mounting on the rear trunnion of other tilting arbor saws or even concealed portions of the support base of tilting table saws. Such concealed mountings provide reasonable assurance that irresponsible operators will not circumvent law or code regulations requiring an adequate guard during all sawing operations and further assurance in the saw illustrated can be provided by applying wired tamper seals to prevent removal of the cabinet walls.
As best seen in FIGS. 1 and 2, hook shaped mounting arm 26 is an integral part of a plate-like kerf splitter 28 of general C-shaped configuration as viewed in FIG. 1, the hook shaped arm 26 comprising the depending stem and lower inturned end of the C-shape. The upper inturned end 29 takes the form of an elongated arm extending forwardly across the rear table edge in the plane of rotation of saw blade 16. The lower free end portion of arm 29 defines an arcuate forwardly and upwardly divider blade portion 31. Divider blade portion 31 extends arcuately upwardly and forwardly from a point 32 lying just above the work support surface of table 13 at the rear of the blade slot in insert plate 17 in the plane of rotation of the blade along an arcuate path generated around the rotational axis of the blade on a radius slightly greater than the radius of the outermost peripheral path of the blade when set at its maximum depth of cut. The upper free end of arm 29 is defined by a vertical full width end segment 33 bisected by the rotational plane of blade 16. This configuration of arm 29 assures an operative kerf splitter which will effectively enter the saw kerf in a workpiece as it passes rearwardly beyond the arcuate rear segment of blade 16 exposed above the table surface and an arm of maximum lateral stability to resist the side pressures in parting the portions of the workpiece defining the developing saw cut kerf.
To adapt the kerf splitter 28 to mount the blade guard 35 of this invention, a through circular passage 36 (FIG. 2) is provided in the upper free end portion of arm 29, rearwardly of end segment 33. Passage 36 closely receives, preferably through a press fit, the laterally centered circular step shoulder 37 of stepped bushing 38 having an axial through bore 39. As best seen in FIG. 2, step shoulder 37 is axially dimensioned to the exact thickness of the metal plate used to form kerf splitter 28 and at one end, the right end as seen in FIG. 2, is formed with a radial flange 40 abuttingly overlying the portion of arm 29 defining passage 36 to automatically position bushing 38 axially with respect to kerf splitter 28.
Bushing 38 is formed with oppositely directed step shoulders 41 of equal and lesser diameter than step shoulder 37 respectively extending axially from the end faces of step shoulder 37 and radial flange 39 to respective minor diameter end step shoulders 42 of equal diameter and length equidistantly axially spaced from the longitudinal center of bushing 38. It follows that the opposite end faces of bushing 38 define respective planes equidistantly spaced from and parallel to the side faces of kerf splitter 28 and the coincident plane of rotation of blade 16. This laterally centered relationship of bushing 38 and kerf splitter 28 relative to the plane of rotation of blade 16 adapts bushing 38 to journallingly support a pair of anti-kickback fingers 43 on the respective step shoulders 42 with a double end coil biasing spring 44 (FIG. 2) disposed therebetween. As best seen in FIG. 2, biasing spring 44 comprises respective end coils 45 loosely surrounding step shoulders 41 and joined at their adjacent inner ends by an integral connector run 46 formed midway between coils 45 with a bridging run 50 disposed to abuttingly engage the upper edge 47 of kerf splitter 28. The opposite outer ends of coils 45 are bent axially outwardly to form respective anchor hooks 48 engaged behind the respective anti-kickback fingers 43 as shown in FIG. 2 to normally bias fingers 43 to their dependent positions shown in FIG. 1 and yieldingly retain fingers 43 against axial shifting movement off of step shoulders 42. It will be appreciated that this assembly of bushing 38, kickback fingers 42 and biasing spring 44 on kerf splitter 38 provides a unitary subassembly8c that can be constructed in advance of mounting the guard 35 and that the close fit of bushing 38 in passage 36 of kerf splitter 28 materially limits tilting of the journal mount provided for anti-kickback fingers 43 assuring their proper free operation at all times.
To assure a rigid non-tilting journalled mounting of guard 35 on kerf splitter 28, the present invention provides a blade guard supporting link 51 (FIGS. 1 through 3 and 5) of channel shaped configuration in cross-section as best seen in FIGS. 2 and 5. Referring for the moment to these latter figures, it will be seen that the spacing of the dependent sidewalls 52 of link 51 is such that the inner sidewall faces freely but closely engage the opposite end faces of bushing 38 while the outer sidewall faces freely but closely engage the opposing planar walls of inwardly protruding, integral lands 53 (FIGS. 4 and 5) formed on the inner faces of dependent sidewalls 54 and 55 of channel shaped guard 35.
As best seen in FIGS. 1 and 3, the connecting web 56 of link 51 terminates inwardly from one end of dependent sidewalls 52 to provide an abutment end face 57 lying in a plane inwardly offset relative to the aligned passages 58 provided in sidewalls 52 at said one end and extends forewardly terminating in the transverse plane defined by the opposite ends of sidewalls 52. A pair of aligned journal passages 59 are provided in sidewalls 52 inwardly of the opposite ends of sidewalls 52. Preferably the axes of the aligned passages 58 and 59 are disposed to lie in a common plane parallel to web 56 centered vertically relative to link sidewalls 52. Assembly of guard 35 with link 51 is preferably first completed to provide a unitary subassembly by inserting the link end containing journal passages 59 into position between lands 53 to align passages 59 with the aligned through guard passages 61 (FIGS. 4 and 5). Passages 61 are formed in the guard sidewalls at a point forewardly of the longitudinal center of guard 35 to impart a clockwise biasing weight component to the forward end of guard 35 for a purpose which will presently appear Passages 61 are of a diameter slightly less than that of passages 59 and a headed pivot pin 62 having a tight, preferably press fit, with passages 61 and passing freely through link passages 59 is provided to journal link 51 for pivotal movement. Head 63 of pin 62 abuts the other face of guard sidewall 54 and shank 64 'protrudes beyond guard sidewall 55. The protruding shank end is then capped with a press fitted cap nut 65 set home to firmly abuttingly engage the outer face of sidewall 55. This construction secures pivot pin in the thickened sidewall portions of guard sidewalls 54 and 55 while the cap nut assures a pivot connection that cannot be disconnected on the whim of an operator by driving pin 62 out of guard 35.
The unitary subassembly of guard 35 and link 51 is then assembled with the unitary subassembly of kerf splitter 28 and kickback fingers 43 to provide a unitary splitter-guard assembly that can be readily installed as a unit and packaged separately for marketing with the saw or as a replacement item for existing saws which are provided with or can be adapted to receive the bracket 22. This final assembly operation is effected by grasping guard 35 permitting the free end of link 51 to depend below the guide sidewalls 54 and 55. The ends of bushing 38 carried by kerf splitter 28 are then entered between the depending end of link 51 and bore 39 is aligned with passages 58. A plain ended pivot pin 64 (FIGS. 1 and 2), dimensioned to closely fit passages 58 and have a journal fit in bore 39, is entered endwise into one passage 58 and passed through bore 39 and the opposite passage 58 to dispose its opposite ends protruding equidistantly beyond the opposed link sidewalls 52. The resulting structure provides free pivoting of pin 64 and link 51 relative to bushing 38 carried by splitter 28. Completion of this pivot connection is effected by press fitting respective spring washers 65 or, if desired, press fitted cap nuts onto the opposite ends into end butted engagement with the outer faces of link sidewalls 52 thereby providing a second pivot connection that cannot be disconnected on whim by an operator The resulting splitter-guard assembly is mountable as a unit on bracket 22. When once installed and the cabinet back wall 24 is secured in place to enclose at least the innermost bolt connection 27, a guard assembly is provided which cannot be readily removed or dismantled to enable the saw to be operated without a guard. In addition, the guard 35 cannot be grasped and swung upwardly and rearwardly to a non-guarding position at the rear of table 13 since the notch 57 in the web 56 which straddles kerf splitter 28 engages the upper edge of the kerf splitter to limit the rearward pivotal movement of guard 35 to a forwardly inclined position indicated by the dot-dash line position D of FIG. 1. From this position, the guard upon release will be weight biased to automatically swing forewardly and downwardly into full blade guarding position designated A in FIG. 1 with the lower edge of guard sidewall 55 in full length bearing engagement with table 13.
To further assure full gurading operation of the guard assembly of this invention, the rear end of guard 35 is provided with an end wall 71 (FIGS. 1 and 6) having a laterally centered vertical slot 72 formed at its lower end with a divergent entrance mouth 73 and delimited at its upper end by a thickened bridging end wall 74 spaaced from top wall 75 a distance to assure full butting engagement with the upper edge of kerf splitter 28 when guard 35 is in its normal guarding position A (FIG. 1). Assuming a workpiece W (FIG. 1) is fed along table 13 into the saw, the upper leading corner of the workpiece will contact the 45 angular front edges 76 of guard sidewalls 54 and 55 forcing guard 35 and link 51 to swing upwardly more or less as a unit around a fulcrum point 77 (FIG. 1) formed by theengagement of the rear corner of bridging end wall 74 with the upper edge of kerf splitter 28 until the front end of guard 35 reaches position B of FIG. 1. At the time this position is reached the upper leading corner will have reached a position below and slightly forewardly of a vertical plane containing the pivot axis of pin 62. Guard 35 will be maintained in proper straddling relation to the saw blade by link 51 and the cooperative engagement of slot 72 and kerf splitter 28 during this movement to house the blade ahead of workpiece W which itself houses the descending blade segment within the developing saw kerf in the workpiece. Relative joumalling movement of link 51 around pivots 62 and 64 takes place to permit this initial swinging movement. As the leading edge of the workpiece passes sufficiently close to the aforementioned plane containing the axis of pivot 62, the weight biasing component of the forward end of guard 35 becomes effective to swing guard 35 clockwise around pivot 62 to position C of FIG. 1. In this position, link 51 will occupy an upwardly and forwardly inclined position relative to the lower edge of guard sidewall 55 which assumes a position parallel to table I3 in edge bearing engagement with the upper surface of the workpiece. In this position, bridging end wall 74 of guard slot 72 will have moved upwardly out of engagement with the upper edge of kerf splitter 28 with the lower portion of slot 72 still in cooperative engagement with splitter 28 to aid link 51 in maintaining guard 35 in straddling guarding position relative to saw blade 16, the emerging saw teeth and the developing saw kerf. It follows therefore that the operator is fully protected against contact with the blade in this position of guard 35.
As the trailing end of the workpiece reaches the aforesaid plane, the biasing weight component of the forward end of guard 35 becomes effective to impart further clockwise swinging movement to the freely suspended guard 35 around pivot 62 causing guard 35 to assume a forwardly and downwardly inclined position across the trailing upper corner of the workpiece In this position, the guard is still in straddling relation to the blade and developing saw kerf to fully protect the operator from the saw teeth emerging from the saw kerf developing in the upper end surface and trailing end of the workpiece. As the workpiece passes beyond the back end of sidewall 55, the rounded forward end of sidewall 55 will have contacted the work support surface of table 13 and the weight component of the guard 35 and link 51 will become effective to cause counter clockwise swinging movement of guard 35 around pivot 62 and clockwise swinging movement of link 51 around pivot 64 thereby lowering the rear end of guard 35 to its normal guarding position A of FIG. 1. During this lowering movement, a rolling action takes place between the rounded foreward end of guard sidewall 55 and table 13 until guard 35 reaches position A of FIG. I.
The relatively wide lateral spacing of link journal passages 58 and 59 along the respective pivot pins 64 and 62 will adequately resist the sidewise canting forces imposed on guard 35 and link 51 due to the canting forces applied to the longer guard sidewall 55 as a consequence of its supporting engagement with table 13 and the workpieces. Tilting of either the blade 16 or table 13 to effect a bevel cut in the workpiece takes place around an axis P (FIG. 6) lying along the intersection of the table work support surface and the plane of rotation of blade 16 in a clockwise direction as viewed from the rear of the saw and in FIG. 6. As a consequence, the guard and splitter assembly assume an angular relation to the work table as indicated by the inclined line 13 of FIG. 6 illustrative of the maximum 45 bevel angle. Since the operator stands at the front of the saw to the left side of the plane of rotation of the blade and the table support surface falls away from the longer side wall 55 relatively speaking in all angular adjustments the longer guard wall remains the supporting wall in all angular positions except for those approaching the maximum position to fully protect the operators hands holding the workpiece. Even in the maximum angular 8 adjustment and adjustments approaching the maximum adjustment, the longer sidewall 55 assures greater protection than would be provided by sidewalls of equal length.
It will be appreciated from the preceeding description that the present invention provides a blade guard assembly that assures maximum protection of the operator during all usage of such saws and in addition a blade guard assembly which can neither be flipped to an inoperative position nor readily removed by careless or thoughtless operators.
While these highly desirable advantages can be secured irrespective of the material employed in producing the guard 35 itself, it is preferable that guard 35 be made of a distinctively colored (preferable an alert orange color) see through plastic material, for example a thermoplastic polycarbonate resin such as General Electric Companys LEXAN, possessing a combination of toughness, impact strength, heat resistance, dimensional stability and good electrical properties. While in normal usage the metal mounting link 51 and its spaced journal passages cooperating with the respective fixedly mounted pivots 62 and 64 are adequate to resist any side thrusts applied to the guard 35 which might tend to shift guard 35 laterally relative to the kerf splitter 28 into the blade from either side, unusually heavy side thrusts applied to the splitter itself in performing its kerf parting function in heavy duty cutting operations could conceivably flex the kerf splitter arm 29 to an undesirable laterally inclined position. To guard against any such unusual operating conditions, the arm 29 rearwardly of divider blade portion 31 may be pro vided with a downwardly protruding lug 8] fitted into a suitable slot in table insert 17 or the table itself or its lower edge could be formed to engage in an upwardly opening slot (not shown) extending rearwardly in the table support surface in the plane of rotation of blade 16.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
What is claimed and desired to be secured by Letters Patent is:
1. A safety blade guard for table type circular saws having a work support table providing an elongated blade passage and a motor driven saw blade arranged for depth of cut adjustment through the blade passage at varying angular adjustments relative to the plane of the table work support surface comprising a support bracket fixedly secured relative to the saw blade beneath the table and having a plate-like portion extending rearwardly beyond the rear edge of the work support table, a kerf splitter plate fixedly secured to said support bracket at a relatively inaccessible point beneath the rear edge of the table and including an upwardly and forwardly directed portion disposed to overlie the table in the plane of rotation of the saw blade at the rear of the saw blade and terminating at its forward end in an arcuate portion overhanging in radially spaced relation the rear segment of the blade exposed through the blade passage; link means pivotally connected at one end to said portion of said kerf splitter inwardly from its forward end for limited swinging movement around an axis disposed at right angles to the plane of rotation of the blade between a forwardly extending guarding position overhanging the exposed blade and an upwardly and forwardly inclined guarding position overhanging the exposed blade, said pivot connection including pivot means non-removably fixed to said kerf splitter with its opposite ends projecting laterally therefrom to fixedly receive said link means; and an inverted U-shaped, elongated blade guard pivotally suspended from the other end of said link means in straddling relation to said pivot connection and the exposed portion of said saw blade in all swing positions of said blade guard, said pivotal suspension including a pivot pin non-removably fixed to said blade guard whereby a blade guard normally biased to operative blade guarding position on the work support table and incapable of being readily removed or swung to an inoperative position is assured.
2. The safety blade guard assembly of claim 1 wherein the blade guard rear end beyond said link pivot connection engages the upper edge of said kerf splitter preventing independent pivotal movement of said blade guard upwardly and rearwardly and the forward ends of said blade guard side walls extend forwardly of said exposed blade portion and are upwardly and forwardly inclined to provide camming surfaces engageable with the leading upper corner of a workpiece fed into the saw blade to pivot the blade guard and link means upwardly and rearwardly as a unit around the axis of the pivot connection to the kerf splitter until the leading upper corner of the workpiece reaches a position immediately forward of said pivotal suspension thereby permitting rapid retrograde pivotal movement of said blade guard around said pivotal suspension into bearing engagement with the upper surface of the workpiece in straddling relation to the developing saw kerf in the workpiece to guard the blade emerging through the workpiece.
3. The safety blade guard of claim I wherein the depending blade guard sidewall adjacent the blade face forming the acute angle with the table work support surface at the varying angular adjustments is vertically foreshortened relative to the opposite blade guard sidewall whereby said foreshortened sidewall is maintained out of contact with said work support table thereby eliminating side thrust forces on the blade guard when angular adjustments are effected to bevel cut workpieces.
4. The safety blade guard of claims 1 and 2 wherein the blade guard is formed of distinctively colored see through plastic to serve as a constant visual warning of the danger zone created by the expoded saw blade por tion while permitting a clear view of the cutting action.
5. The safety blade guard of claim 1 wherein said kerf splitter is through apertured and bushed to journal said first pivot pin and said link means comprises a short, rigid metal, inverted channel member having respective axially aligned pairs of passages formed in the adjacently related sidewalls at one end to fixedly receive said first pivot pin thereby relegating pivotal wear to the bushing of said kerf splitter and the portions of the pivot pin enclosed thereby whereby canting forces applied to the blade guard during use of the saw will be torsionally resisted by said link means.
6. The safety blade guard of claim 5 wherein said bushing comprises a metal bushing having a center portion fitted to said kerf splitter through aperture, opposite end faces spaced apart to have light bearing engagement with the opposing areas of the adjacently related inner faces of the sidewalls of said channel member, and a centered longitudinal through bore coaxially related to the aligned pair of passages in said channel member one end.
7. The safety blade guard of claim 6 wherein the periphery of said metal bushing adjacent the opposite kerf splitter side faces is reduced in diameter to form a first pair of annular steps and the opposite ends are further reduced in diameter to form respective annular journals; respective anti-kickback fingers are journalled on said annular journals; and a torsion biasing spring is provided comprising a pair of axially spaced coils respectively encircling said first pair of annular steps with their adjacent ends interconnected in spanning relation to the upper edge of said kerf splitter and their outer ends drive connected to said anti-kickback fingers to bias them to dependent operative position, thereby forming a captive anti-kickback assembly.
8. The safety blade guard of claim 1 wherein said blade guard has dependent sidewalls which are inwardly thickened and coaxially through apertured at opposed points rearwardly'offset from its longitudinal center to closely but freely receive said links means, said pivotal suspension includes a pivot pin fixedly carried in said blade guard side walls and journalling said link means, and said link means comprises a short rigid metal channel member having respective axially aligned pairs of journal passages formed in the adjacently related sidewall ends to journallingly receive said pivot pin of said pivot connection relegating piv otal wear to the link means and the portions of the pivot pin enclosed thereby and providing spaced bearings surfaces whereby canting forces applied to the blade guard during use of the saw will be torsionally resisted by said link means.
9. The safety blade guard of claim 8 wherein said pivot means comprises a headed pin having its head disposed in face butted engagement with one sidewall of said blade guard and a shank protruding through and beyond the opposite sidewall of said blade guard-and a cap nut drive fitted to the protruding end of said pin shank into end butting engagement with the opposing blade guard sidewall operative to obviate ready removal of said headed pivot pin.
10. A splitter and safety blade guard assembly for a table type circular saw having a mounting bracket disposed below the rear table edge in fixed relation to the saw blade comprising a generally C-shaped splitter blade the lower arm of which is fixedly secured to said mounting bracket and the upper arm of which extends forewardly from the rear table edge in the plane of rotation of said saw blade to a point forewardly of a vertical plane containing the rotational axis of the saw blade, said splitter blade upper arm defining an arcuate knife edge disposed in radially spaced overlying relation to the rear segment of the exposed saw blade and having a laterally directed through passage adjacently related to its upper edge in a vertical plane offset rearwardly from its front end a distance less than half the longitudinal distance between the opposite ends of said knife edge; a journal bushing fixedly supported in said splitter blade passage with its opposite ends projecting equidistantly beyond the opposite faces of said splitter blade; an inverted, U-shaped, elongated blade guard disposed in straddling relation to said portion of said splitter blade defining said arcuate knife edge and the front segment of the exposed saw blade, said blade guard rearwardly of its longitudinal center and adjacent its connecting web being provided with inwardly thick ened, laterally spaced lands having respective laterally aligned through passages therein; a rigid channel shaped guard mounting link having dependent sidewalls the respective ends of which are spaced to receive and have bearing contact with said ends of said beushing and to be received between and having bearing contact with said lands of said guard and respective pairs of aligned through passages in said respective ends; a first pivot pin extending through said bushing and the cooperating aligned passages of said one link end and dimensioned to provide a pivotal fit with said bushing and fixed fit with said one link end; and a second headed pivot pin having a shank extending through said aligned guard passages and the cooperating aligned passages of said other link end, said shank being dimensioned to provide a fixed fit with said guard and a pivotal fit with said link.
11. The splitter and safety guard assembly of claim wherein said headed pivot pin is positioned to establish a face butting engagement with one guard side wall and has a shank of sufficient length to protrude beyond said other guard wall and a cap nut is press fitted onto the protruding shank end into face butting engagement with the other guard side wall to thereby prevent the headed pivot pin from being driven out to effect removal of the guard.
12. The splitter and safety guard assembly of claim 10 wherein said first pivot pin is of a length to assure protrusion of its opposite ends beyond the opposite side wall of said link and respective spring washers are press fitted on the opposed pin ends into face bearing contact with the opposite side walls of said link to thereby prevent the first pivot pin from being driven out to effect removal of said link.
13. The splitter and safety guard of claim 10 wherein the connecting link at said one link end is inwardly notched relative to the sidewall ends to provide an end abutment face adapted to abuttingly engage the upper edge of the splitter blade in relative pivotal movement of said link and bushing to limit the upward and backward swinging movement of said link to prevent the guard from being swung to an inoperative guarding position.
14. The splitter and guard assembly of claim 10 wherein said bushing between said link sidewalls is stepped to provide first and second pairs of annular journals, respective anti-kickback fingers are journalled on said first pair of journals in dependent relation to operatively cooperate with the upper surface of a workpiece at opposite sides of the developing saw kerf to prevent the workpiece and the severed seg ments of the workpiece from being kicked out of the saw by the rotating blade during a sawing operation and a double coil spring having an interconnecting bridging run engaging the upper edge of said splitter blade and respective hooked outer ends engaging said antikickback fingers has its coils mounted on said second pair of journals whereby said spring will be tensioned by rearward swinging movement of said anti-kickback fingers upon feeding a workpiece into the saw and against the kickback fingers to forcefully engage the kickback fingers with the workpiece during the sawing operation.
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|U.S. Classification||83/478, 144/251.1, 83/508.2|
|International Classification||B27G19/02, B27G19/00|
|Apr 25, 1984||AS||Assignment|
Owner name: DELTA INTERNATIONAL MACHINERY CORP., 400 NORTH LEX
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ROCKWELL INTERNATIONAL CORPORATION;REEL/FRAME:004249/0129
Effective date: 19840412