US1598498A - Safety device - Google Patents

Description

Patented Aug., 31, 192e.

ROBERT E. PAJJEE, or GLENDALE, MISSOURI.

snrn'rv DEVICE.

Application Ied October 19, 1925. Serial No. 63,387.

This invention relates to safety devices, and more particularly to a guard for preventing injury to an operator by the rotatingcutter of a woodworking machine or other machines of similar character. It has for its objects to produce a relatively simple, e'i'licient and practical device for the above noted purpose, which is readily applied to the machine without material alteration thereof or in the least interfering with its regular operation or the manipulation of the work thereon; to improve generally upon devices of its character; and to attain certain advanggtages as will more fully appear in the followingdescription.

The invention consists in the novel construction and operation of a guard normally surrounding the cutter in proximity to the work-table or support, but being liftable and automatically operated by the work pressing against it when moving` in `an direction on the table or support. It further consists in the parts and combinations and arrangements of parts hereinafter described and afterwards pointed out with particularity in the appended claims.

In the accompanying drawings forming part of this specification and illustrating a practical adaptation of the invention Figure 1 is a view partly in side elevation and partly in vertical section, showing the device as applied to the machine and the parts in normal position;

Figure 2 is a top plan view of the horizontal hanger arm detached from the supporting standard;

Figure 3 is a detail view of the retaining,` plate detached from said hanger arm;

Figure 4 is a top plan view of the handwheel for effecting; the adjustment of the hanger arm on the supporting` standard;

Figure 5 is an end view of the bushing on which the hand-wheel is adjusted;

Figure 6 isa section on the line 6 6 of Figure 1;

Figure 7 is a section on the line 7`7 of Figure 1;

Fig-ure 8 is a detail view of the guardelevating nut and the bushing or plug which co-operates therewith; and

Figure 9 is an end view of said bushing or plug'.

Referringr now to the drawings, the nu moral 1 designates the work-table of an erdiniry woodworking machine commonly i-iy an, i gli l, i ll-lifiiailill; I

-rower slot 23 until said enlargement 19 groove 7, is a horizontal hanger arm 9. This arm is secured in its adjusted position by a set-screw 10, and co-operating with said arm is a hand-wheel 11 whose hub portion 12 is internally screw-threaded to lit on the externally screw-threaded portion of a bushing 13 which is sleeved on the post 6. vSaid bushing; 13 is provided with a key or spline 14 slidably fitted in the groove 7, and it is fastened in its adjusted position on the post by a set-screw 15.

Suspended from the horizontal hanger arm 9 is a tube 16. This tube is provided withua head 17 in its upper end portion, said head having an upwardly extending axialk neclror shank 18 on the end of which is an annular flange or enlargement 19. This enlargement 19 is fitted somewhat loosely in a circular recess 2O provided therefor in the hanger arm 9, said arm being provided with aslot 21 wide enough to permit the enlargement 19 to pass freely therethrough, and said slot 21 being' connected with an axial opening22 at the bottom of said recess 2O by a narrower slot 23 which is of a width substantially the same as the Vdiameter of said opening 22 and permits the neck or shank portion 18 to pass freely therethrough. By this arrangement, the neck or shank portion 1S is movable longitudinally throughv the wider slot 21 from the under side of said arm 9 until the enlargement 19 clears the upper side of said arm 9, after which the neck or shank 18 is readilypassed transversely through the naris in position to enter said recess 20.

Inter-posed between the bottom of said recess 2() and said enlargement 19 is a washer 2li: of rubber or some suitable felted or fibrous mass possessing a' certain amount of 1esilienc v,while on top of said enlargement 19 isa disk 25 of material similar in character to said washer 211, the disk being covered by a retaining platev` or disk 26, which, as shown, is a circular disky andieleaxsably areal. :in piace cy s :557i lily rangement, the tube 16 is normally suspended vertically from the arm 9, yet it is capable of swinging movement when pressure is brought to bear laterally upon it, and to permit this swinging movement, within certain limitations as will later be described, the wall of the opening 22 is downwardly fiared, as at 28 (see Figure 1).

Sleeved on the tube 16 is ay collar 29, and to afford an easy movement of the latter on the tube, as will be more fully set forth later on, antifriction bearings 30 are preferably interposed between said members. Secured on the collar 29, as by screws 31, is an annular housing or cage 32 which normally surrounds the cutter 4 and rests upon or` has its lower edge in close proximity to the worktable 1. This housing, which constitutes the guard proper for the cutter, may comprise a top wall 33 with a plain cylindrical flange, but it is preferable to provide said flange with a multiplicity' of apertures of suflicient size to permit a view of the Cuty ter yet small enough to prevent the operators lingers from passing therethrough. Preferably, these apertures are vertical slots 34, and, obviously, the same effect may be had by constructing the guard flange of a multiplicity of rods or bars in cage-like arrangement.

In practice, the guard housing or cage may be made in different sizes to accommo date cutters of various forms and sizes, and they may be obviously interchangeably mounted on the collar 29 by having an uniform arrangement of the securing screws 31 for the attachment of all sizes.y

Secured in the upper portion of the tube 16 is a cross-head or support 35 in the center of which is an antifriction bearing 36. Supported axially from the inner ring 37 of said bearing is a shaft 38. This shaft, as shown, has a reduced upper end portion 39 affording a shoulder to engage the under side of said bearing ring 37, and it is further reduced in diameter and screw-threaded, as at 40, to receive a clamping nut 41.

rlhe shaft 38 is provided throughoutl the major portion of its length with screwthreads 42 of relatively long pitch, and working on said threaded portion is a cylindrical nut 43 having an annular flange 44 at its lower end. This nut 43 is located in a cylindrical box 45 having an axial opening in its top wall 46 through which said nut is freely slidable, while said flange portion 44 of the nut is slidably fitted to the interior face of said box. On the under face of the flange portion 44 is an annular series of serrations 47 which co-operate with a counterpart series of serrations 48 on the upper face of a bushing ring 49, which latter is screwthreaded into the lower end portion of said box or otherwise secured therein to afford an abutment for said nut. The nut is normally held in engagement with said member 49 by a. spring 50 which is interposed between the top wall 46 of the box and said flange 44 of the nut and being under snifficient tension so that, under normal conditions, the interlocking of the serrations 4T and 43 holds the nut from rotation in said box, and whereby, when said shaft 33 is rotated, the nut is caused to move lengthwise on its screw-threaded portion 42.

The box 45 has an annular flange 51 at its lower end which is provided with a series of arcuate notches 52. Slidably secured to the under side of said flange 51 is an annular member or ring 53, said member beijmr supported by segmental plates or disks 54 which span said notches 52 and are apertured for thereception of screws or bolts 55 which enter said n'ielnber and by which arrangement there is limited relative m vement be- ,sai d tube, yet being held from rotation there- A clutch member 59 having a screwthrcaded stem or shank GO which is threaded reversely to the threading 42 of the shaft 33 is secured axially in the end of the shaft or spindle 3 of the cutter 4. This clutch member 59 is provided with an antifriction bearing 61 in the inner ring member of which the lower end portion of the shaft 33 is fitted slidably and laterally supported. A co-operating clutch member 62 having a central hub portion 63 is slidably mounted on said shaft 33 as by a slot-and-pin connection whereby independent rotation of the member 62 is prevented but it is permitted movement longitudinally on the shaft. That is to say, said hub portion is provided with two di ametrically opposed longitudinal slots 64 through which the ends of' a cross-pin 65 in the sha *t 33 projects. lnterposed between said cross-pin 65 and an annular shoulder afforded by a taper l l 66 on the upper end of said hub portion 63 is a spring 67 which is somewhat weifer than the herembefore described spring' .3o

the function of said spring 6.7 being merely to yieldably hold said clutch member 6i! diffveng ged from said clutch member 59, while the spring 50 must be strong enough to ncrmally support the combined weight of the bof: 45, ring member A53, collar 29, housingv 32 and the associated parts therewith.

Fixed on the shaft 33, as by a pin 63, is an abutment member ("9 having an inverted tapered head 70 in opposed relation to the described.

A guard housing 32 ot' 4the proper size according to the cutter being used on the machine having been selected and mounted on the collar 29, and theelutch'member having been secured in the end ofthe cutter shaft or spindlel 3, the arm is then adjusted to the proper heighten' theV postor supporting standard 6, so thatthe clutch member 62 is clear of engagement with the clutch member 59 as shown in Figure 1. This adjustment is readily effected by loosening' the set-screw 10 and setting the arm 9 as accurately as possible and then tightening the set-screw. `The bushing sleeve 13 with the hand-wheel 11 thereon is then .adjusted with relation to said arm 9, and if the latter needsfurther `adjustment `the setscrew 10 may be` loosened and the hand- Wheel 11 moved up or down, as the ease may balon `said bushing sleeve 13 so that the arm 9 is accordingly raised or lowered and the linal adjustment effected to the minutest degree. l

Preferably, the guard `housing 32 rests on the work-table 1, but, if desired, in some cases, it may be suspendedr just aslight distance clear of the table by proportioning the slots 58 in the tube 16 so that when said tube is at the proper elevation to have the clutch members 59 and 62 normally disengaged the arms or extensions 56 of the `member 53 rest at the lower ends of said slots 5S and the marginal portion of the guard housing is clear of the table.

Obviously, the shaft 38 is normally idle owing to the disengagement of the two clutch members 59 and 62.` I-lowever, when the work is moved on the table'land pressed against the guard housing 32 the tube it) is swung accordingly on` its supporting head 19, the slidable connection between said box and ring member 53 aliorded by the arrangement of the notches 52, supporting plates or disks 54 and screws or bolts 55 permitting this.

As the tube l'swings thus, the 'wedge ring Y 71 is forced between the two heads G6l and 70, and the head T0 being stationary on the shaft 33 the clutch member 62l is moved downward against thevtension of the spring i 67 kand into engagement vwith Y the' clutch njlcmber 59, whereupon v said shaft 433 is eau,d to rotate with tn'esliaftior spindle Assuming vthat said shaft or spindle 3 is rotating counter clockwise, looking at the cutter 'from above, and the screw-thread 4L on said shaft 38 being a lett-hand thread as shown in the drawings, the nut 43 which is normally held from rotation in said box 45 is caused to travelupward on said shaft 33, for the reason that, while there is limited sliding` movement between said box and said ring member 53, any rotative movement of said box 45 about said shaft 38 is arrested as soon as the walls of the notches 52 engage said screws or bolts 55. fis said nut 43 travels upward the box 45, supported by said spring 50, moves upward with it, and the guard housing 32, of course, is accordingly elevated. This upward travel ot' the parts continues until the work slides under said guard housing and as soon as lateral pressure is released from said guard housing the pressure of the wedge ring 71 is released from thehead of said clutch member 62 and the spring GT disengages the clutch member 62 from said clutch member 59, whereupon the shaft 33 ceases to rotateunder the power oi said shaft 3,.an`d it being freely supported in its antifriction bearings 36 and 61 it is rotated in the opposite direction by the action oit' the nut 43 on the threads 42 thereot as the guard housing 32, augmented by the combined weight of the connected parts between it and said box 45, drops upon the work and back to normal position about the cutterv as soon as the work is withdrawn fromunder said guard housing.

Y In machines of the character on which the present invention is primarily.designed to be` used the cutters rotate at a very high rate of speed, yet under the ordinary'conditions the device has been found to operate ideally. However, if the work is unusually rough so as to create an undue amount or rictional engagement with the edge of the guard housing32 while passing thereunder and thereby tend to continually keep the clutch members 59 and 62 engaged or should any condition exist so asto cause thehousing to continue moving'upward after the work is thereunder a cushioned stop device may be employed. To this end a split ring member 74 (sec Figures 1 and 6) may be clamped about the tube 16 in different adjusted positions, said ring member being provided with apertured ears 7 5, 76 at its ends for the reception of a clamping bolt 77. This ring member may have two or more vertically apertured lugs 73 through which are slidably Fitted springpressed bars 7 9, the springs 8O being interposed between the under sides or' said lugs and headsl 31 at the lower ends of said bars.

In practice, the thickness of the work to be operated hpon having been determined, the ringmemberl74 adjusted on said tube 15sothatthV1 Vunder faces ofthe heads Si of thebars 7 are in a plane just slightly above that where the upper faces of the ei:- tensions 56 or the upper end of the sleeve 29, as the case may be, reach when the guard housing has been elevated sufficiently to allow the work to pass thereunder. Therefore, should the housing continue to move upward beyond the predetermined plane, it will be arreflzted by said member 79 with cushioning etl'ect, however, due to the orovision of the sirirings 80, and, as may be here stated, 'd springs 80 being considerably stronger than said spring 5t), the latter will yield under the resistance of the former, whereby the serrations 47 of the nut fl?) will ride out of their seated engagement in the serraHons of the member et) so that said nut is free to re with said screw-thi eaded portion of the shaft 38 within the bolt i5 and without further endwise movement during such disengagement of said serrated portions.

Furthermore, should the operator press the work against the guard housing 82 with excess force or should anything happen to hold the guard housing or the connecting parts between it and said nut 43 from rising with said nut during the forceful rotation of said shaft 3S, the spring 50 will yield just as above described in connection with the functioning of the said cushion safety stop.

lt is noted that while the tube 16 is capable of swinging on its supporting head 19 in the operation of the device as herein described, the shaft 3S is at all times maintained in substantially true axial alinement with the shaft or sprindle 3, as said shaft is supported at its upper end relatively near said supporting` head 19 and is thrown but slightly outv of its normal position. Said shaft therefore rotates with substantially no appreciable wabble during the operation of the device.

Obviously the device admits of considerable modification without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, it is not limited to the specific cons yruction and arrangement shown in the drawings.

1What is claimed is:

l. In a guard of the character described, a housing normally surrounding the cutter', said housing` being capable of vertical movement and limited lateral movement. and moans for raising said housing including a nornially inactive screw-shaft axially alined 7ith the axis of the cutter, a clutch member rotating` continuously with said cutter, a cooperative clutch member on said screw-shaft, and an actuator element correlated to one of said clutch members for effecting the engagement of said two clutch members when sa`d housing is subjected to forcible lateral pressure.

2. In a guard of the character described, a housing normally surrounding the cutter,

said housing being capable of vertical movement and limited lateral movement, a vertically suspended swing-able carrier for said housing, a nornially inactive elevator-shaft rotatably mounted in said carrier in axial alinement with the axis of the cutter. said elevator-shaft being screw-threaded, a counterpart screw-threaded element working on said elevator-shaft and connected with said housing whereby, when said elevatorsha t is r tatcd in one direction the housing is raised on said carrier, a clutch memberota continuously with the cutter and concerrU ally with said elevator-shaft, a cooperative crutch. member longitudinally slidable on said elevator-shaft but lit-ed to rotate th "ewith, and means on said carrier for actuating said second mentioned clutch inember to effect the engagement of said two clutch members whensaid housing is subjected to 'forcible lateral pressure so as to swing said carrier.

in combination with a machine of the character described, having a work-table and cutter thereon rotating about a vertical airis, a vertically adjustable support on said table, a swingable carrier suspended from supijort, a l'iousing vertically movable on said carrier and normally surroundingr aid cutter. and means for raising said housing comprising a clutch member mounted atially with respect to said cutter and rotatable therewith, said clutch member having' journal bearing therein, said carrier having a liournal bearing in its im ier portion, an elevator-shaft rotatably supported in. said two mentioned journal bearings, and having screw-threads thereon, a counterpart screw-threaded element working on said clevator-shaft and connected to said housing whereby, when said shaft is rotated in one direction said housing); is raised, but when said shaft is relieved of power said housing returns to normal position. a clutch member sleeved on said elevator-shaft to slide longitudinally thereon but being fixed to rotate therewith, and means for actuating said clutch member so as to engage said clutch member on said cutter when said housing is subjected to forcible lateral pressure sufficient to swing said carrier on its support.

4. In a guard of the character described, a housing normally surrounding the cut,- ter, said housing being capable of vertical movement' and limited lateral movement, means for raising said housing including a normally inactive power element anl a normally disengaged power element in co-operative relation to said first mentioned power element.r said second mentioned power element operating continuously with the cutter, means for connecting said two mentioned power elements when said housing is subjeeted to forcible lateral. pressure, a yieldable operative connection between said first mentioned power element and said housing, and an adjustable stop element for limiting the upward travel of said housing and effecting the release of the connection between said housing and said power element.

5. In a guard of the character described, a housing normally surrounding the cutter and being capable of vertical movement and limited lateral movement, a vertically suspended swingable carrier for said housing, a support for said carrier comprising a standard, a horizontal arm feathered on said standard, means for securing said arm in adjusted position, an externally screwthreaded sleeve feathered on said standard belowsaid arm, means for securing said sleeve in adjusted position, and an adjusting member having a counterpart screwthreaded portion working on said sleeve and co-operatively engaging the under side of said arm.

6. The combination with the work-table of a machine of the character herein described, and a cutter on said table rotating about a vertical axis, a standard on said table, a horizontal arm vertically adjustable on said standard, a tubular carrier member swingably suspended from said horizontal arm in substantial axial alinement with the axis of said cutter, a housing vertically slidable on said carrier tube, an annular clutch member mounted axially of the cut-ter and rotatable therewith, said clutch member having a journal bearing therein, a journal bearing in the upper portion of said carrier tube, a shaft supported at its upper end in said journal bearing in said carrier tube and having its lower end supported in said journal bearing in said clutch member, said shaft having screw threads thereou, a box surrounding said shaft and having a limited slidable connection with said housing, a counterpart screw-threaded element working on said shaft, said element being located within said box and having a releasable interlocking engagement therewith, a spring for yieldably maintaining such engagement and being capable of sustaining the combined weight of said. box and said housing when suspended therefrom, an

abutment member on said shaft having an inverted annularly tapered head, a clutch member sleeved on said shaft to move longitudinally thereof but being fixed to rotate therewith, said clutch member having a counterpart tapered head opposed to that of said abutment and a clutching portion in co-operative relation to said first mentioned clutch member, a spring for yieldably holding said second mentioned clutch member against said abutment member and disengaged from said first mentioned clutch member, an annular wedge element supported between said tapered head portions of said abutment and'clutch member, said wedge element being bearing in said carrier tube whereby, when said housing is subjected to forcible lateral pressure to swing said carrier tube on its support the engagement of said two mentioned clutch members is effected.

7. In a guard of the character described, a vertical elevator-shaft having screw threads thereon, a housing support comprising a cylindrical box surrounding said shaft, a cylindrical nut rotatably fitted and longitudinally slidable in said box and working on the screw-threaded portion of said shaft, said nut having an annular flange at its lower end, the under side of said fiange being serrated, an annular bushing in said box having serrations on its upper side to cooperate with those on said nut, and a spring interposed between the top wall of said box and said annular flange of said nut.

8. In a guard of the character described, a suspended swingable carrier member, a screw-shaft journalled at its upper end in the upper portion of said carrier member and at its lower end independently of said carrier member, a guard housing vertically movable on said carrier, a box surrounding said screw-shaft and having a limited slidable supporting connection with said housing, a nut working on said screw-shaft within said box' and having a spring-pressed releasable interlocking engagement with said box, and a clutch member on said screwshaft actuated by the swinging of said carrier member.

ROBERT F. PADEN.

loosely fitted on a circular

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