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Publication numberUS1811577 A
Publication typeGrant
Publication dateJun 23, 1931
Filing dateAug 21, 1930
Priority dateAug 21, 1930
Publication numberUS 1811577 A, US 1811577A, US-A-1811577, US1811577 A, US1811577A
InventorsCrowe John M
Original AssigneeStanley Works
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hand tool
US 1811577 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Jun 23, 1.931. J. M. cRowE 1,811,577Y

HAND TOOL Filed Aug. 2l, 1950 INVENTR A-ToRNEYs Patented June Y23,;-



NEW BRITAIN, CONNECTICUT, A CORPORATION or CONNECTICUT HAND Toon H.epp1ieanon mea August 21, 1930. `serial No. 476,758.

This invention relatesV to Vportable powerdriven hand tools adapted to be applied bodily to the workand moved therealong by the operator. A 'saw is an` example :of such a..

tool, wherein it will be apparentthatguarding means lfor'the moving blade is essential' to the safety ofthe operator.

There has been developed for'l the purpose in the art a type of guardmovable on: theV frame which carries the blade, to-advance or -Iecede to guard 'or expose a cutting portion of the -blade, together. with means tending toadvance the guard, and latch-means for automatically 'Y securing "the guard pin full 1 guiarding4 position. In addition, there has been associated with these parts means for releasing the latch at the will of the operator.`

The latch release means may be arranged for actuation-.either by engagement of. the tool with the work, or by direct operator effort. Such-altool and such structure-'ashas been described is set forth `more in detail in my copending application, Serial No.v 438,47 4, filed March 24, 1930, and this invention .coinprises generally improvements` thereupon. ',Ihereinappears a latch release for4 the guard, arranged for actuation by vthe thumbof the operators handV which graspsone .of the tool Vl,2aiticularlyi it is the obec'trof this invention toprovide against such possibility, and more-in detail to so arrange the operator-operated latch lrelease a's'tofallow relatching of the guard Vin-full guarding position,l a'tfany time subsequent to its unguarding movement followingunlatching and regardless of any however, when theguard has :4 movingy blade yet-the latch would be inopera-v manipulation or inadvertent setting Yof the latch release means possible under 'the `circumstances. f

Y The exact nature of this invention together withffurther objects and advantages thereof will `be apparentfrom the following descripy tion taken inrconnection with the accompanying drawings, inl which Fig. l shows a motor-` driven saw inwhich is incorporated an arrangementxembodying this invention, parts being broken away to show details -of`con struction; Fig. 2 isV an enlarged detail of the same wherein'broken lines are arranged to indicate the alternate Apositions of the parts;

Fig. 3 is a'detail section as in the planeindicated line 3-3, Fig. `1; Fig. 4 is a detail illustrating the action of the trip employed;V and Fig. 5 is a detail viewin section showing the manner of mounting the trip and taken as in theplane of line 5 5, Fig. 4, butlindicating the trip as in normal ,or'uprightpositionl With reference now tothe drawings, the

Vprincipalparts of the tool comprisefa'frame I having a rotary cutting blade 2 operatively mounted thereon, a motor 3 arranged to drive the blade, a pair of handles 4,5, and guarding Vmeans for theV blade. The guarding means comprises 'two principal members, a fixed guard ,6, in reality part of the-frame eX- tended to enclose the upper half of the blade,

anda .movable guard member 7 withv which I we are here primarily concerned and which has'pvotal connectionwith the frame as at 8 to move upwardly Awithin the fixed guard portion' 6 of the frame in telescoping 4relation therewith, `to uncover theworking portion of the blade.- The guard 7 has a workengaging runnerlportionn 9 which is longitudinally slotted in the usual manner to clear the blade 2 andis yieldably urged to the full guarding position indicated Fig.. 1` bya spring 10. It will be apparent that whenthe runner 9 'is resting upon the work the opera-V ,tor by depressing the forward handle 5 and raising the rearward handle'4 may move the frame l Vand parts carried thereby, about the pivot 8 to Vlower the .blade 2 through'the runnerf 9 andinto the worlgand thereafter the toolmay be advancedalong the work to complete the cut; and :when-.the tool is raised M from the work the spring 10 will return or advance the guard 7 to its original and illustrated full guarding position.

For the purpose of limiting this advancing movement of the guard the fixed guard 6 is provided with a slot- 11 arcuate about the axis 8,' and the movable guard 7 is provided with a lever 12 carrying at its free end a roller 13 projecting into the slot 11. The length of the slot 11 is such that the roller 13 will reach the lower end of the slot as the guard 7 attains full guarding position about the blade. A stop 16 may be adjustable along the slot 11 to limit swinging of the guard 7 in the opposite direction and thus limit the depth of cut ot' the blade.

In order that the guard 7 be automatically and positively retained or latched immediately upon reaching its full guarding position, the slot 11 is extended at its lower end by an offset 17 and the lever 12 is urged in the direction of this ofi'set about its pivot point 14 by a spring 15; so that the roller 13 will immediately and automatically enter the ofi"- set to latch the guard 7 whenever the guard attains full guarding position.

In order that the guard may be unlatched by engagement of the tool with the work, the lever 12 is provided with a downwardly extending `portion 18 the tip of which projects through a slot in the face plate 9 and therebeyond; so that with the parts in the position shown Fig. 1, the tool may be presented to an edge of the work and advanced thereagainst and the lever 12 will be moved by its portion 18 to unlatcli the guard 7.

What Vhas thus far been described is not new but will be found set forth in substance in niy Patent No. 1,644,326, issued October 4, 192 Y In order that the operator may directly unlatch the guard 7, I mount a lever at 19 on the fixed guard 6, the lever having one end 2G projecting through an opening 21, and

therebeyond terminating in a thumb piece 22 adjacent the end ot the handle The other end 23 of the lever extends downwardly within the fixed guard 6 and terminates in a hook formation as at 24 carrying at its end a trip 25.. Within the handle is a plunger 26 bearing against the thumb piece 22 and yieldably urged outwardly of the handle by the spring 27 to maintain the latch release parts in the position indicated F ig. 1, and in full lines Fig. 2, motion of the lever arm 2O being limited for theV purpose by the end of the opening 21.

The trip 25 is pivotally mounted on its end of the hooked lever arm 23 to move in clockwise direction upon the lever as Afrom the position indicated Figs. 1 and 2, to one about 90 therefrom against the action of `the spring 25a; but the trip cannot move in the counterclockwise direction from the po- G5 sition indicated in these figures. The locations of the pivotal connection 28 of the trip 25 and the actual end of the lever arm 23 are both below the roller 13 when the roller is in the slot offset 17; so that when the trip is moved to the right Figs. 1, 2 and 3, relative to the roller, the roller will be moved by the trip, yet when the trip is moved to the left relative to the roller the trip will simply be tilted by the roller until it progresses tlierebeyond. To this end the member 23 may be simply a sheet metal stamping as indicated in the drawings, the trip member 25 may likewise be a piece of sheet metal folded about the end, of the hook member as shown Fig. 5, and the spring 25a may be welded to the end of the hook member with its free end extending into the trip member.

The proportions of the hook member are such that when the lever arm 23 is moved to the eXtreme right-hand position indicated by broken lines as at A Fig. 2` the path of the roller 13 between its broken line position B at the end of the slot 11 and its full line position Fig. 2 at the end of the offset 17 will be free. In other words, the curve of the hook passes below the offset 17.

Gperation will be as follows, beginning with the parts in the position indicated Fig. 1 and in full lines Fig. 2. Vhen the operator wishes to release the latch to allow the movable guard 7 to recede and expose the blade 2, he may depress the thumb piece 22 against the action of the spring 27. This moves the lever arms 23 counterclockwise about the pivot 19. By this lever motion the roller 13 moves from the ofset or notch 17 into a position at the end of the slot 11 against the action of the spring 15.

Vith reference to Fig. 2, movement of the arm 23 will be from the full line'position to the intermediate broken line position C and that'of the roller 13 from full line position to broken line position B. Thereupon the movable guard 7 is free to swing upwardly and theblade 2 may be projected into the work by relative motion of the parts about the axis 8, the roller 13 progressing along the slot 11. Thereafter the thumb piece 22 should be released whereupon the lever .2023 will be returned by the spring 27 to its full line'position Fig. 2; so that whenever the tool is withdrawn from the work the movable guard 7 will besnapped to full guarding position by the spring and will be there latched by the roller 13 under the action of the spring 15. i i

Suppose, however, the operator inadvertently retains pressure upon the thumb piece 22. As the roller 13 moves upwardly along the slot 11, as soon as the roller clears the end of the hook member or rather the trip thereof, the arm 23 will progress from its C I position to its A position Fig. 2 so that thereafter the roller may position as before but now within the curve still return to latching vtrip is chamfered off so that in effect the hook member nose terminates on a diagonal. By this arrangement, should by any possibility the nose be held by the operator in'reg' istrywitli the slotV 1l after release of theV roller 13 thereinto, so that return motion of the roller under the action of the spring 10 Would cause engagement of the roller with the end of the trip member; then a Vcamming engagement ofthese two parts wouldftale Y place, moving the hook membercounterclock-wisel Figs. l and 2, to allow the roller to enterV the notch'l.

What I claim is: Y

l. Ina portable power-driven hand tool adapted to be applied bodily to the work and moved along the saine by the operator, a frame, a cutting blade operatively mounted thereon, blade-driving means, aguard movably mounted on said frame to advance or recede to gua-rd or expose a cutting portion of said blade, means Vtending to advance` said guard, latch means for automatically securnl ing said guardv in full guarding position, op- `eratoroperatedmeans associated with said latchV to release said guard therefrom and arranged to be ine'ective to prevent relatching f of the guard following the guard-releasing operation and recession ofV the guard.

2. In a portable power-driven hand tool adapted to be applied bodily tothe workY and moved along the same by theoperator, a

release means for said guard arranged for guard-unlatching'movement by theoperator and,`dependent upon recession of said guard,

for vfurther moveinent'therebeyond to a position ineffective to prevent relatching of said guard. I

4. In a portable power-driven hand tool adapted to be applied bodily to the work and moved along the Ysame by the operator, a frame, a cutting blade operatively mounted thereon, blade-driving means, aguard movably `mounted on said frame to advance or recede to guard or expose a cuttingl portion of said blade, means tending to advance said guard, latch means for automatically securing said guardin full guarding position, operatoroperated means associated Ywith said -latch to release saidguard therefrom and arrangedv to be ineffective to prevent relatching of tlieguard. K v j 5. In aportable tool, afframe, a cutting blade operatively mounted thereon, means for operating said blade, guarding means.- Vadapted to advance or retreat to guardor eX- pose a cutting portion of said blade, means tending to advance said guarding means, Y means for securing `said` guarding means against accidental retreat, means adapted for actuation by Vengagement with the work for,

releasing said guarding meansv to allow the same to retreat, a handle forV said tool, and'operator-operated means associated with said handle and with said securing means to release said guard, and arranged to be ineffective to prevent `resecuring 'of the guard."

In testimony whereof I hereby vaffix my signature. Y


frame, acutting blade operatively mounted thereon, blade-driving means, a guard movably mounted on said frame vto advance or recede. to guard or expose a cutting portionv of said blade, means tending to Vadvance said guard, latch means for automatically'securing said guard in full guarding position, and

Vrelease means Jfor said rguard arranged for guard-unlatching movement by the operator,

VandV for further movement therebeyond to a position ineffective Vto prevent relatoliing of said guard.

3. In a portable power-driven hand tool f adapted to be applied bodily to'the'worlr and moved along the same bythe operator, a' frame, a cuttingblade operatively mounted tliereon,bladedriving means, a guard movably mounted on said frame to advance or recede to guard or'eXpose a cutting portion ofV said blade, means tending to advanceV saidv `guard,latch means for automatically securing said guard in fullV guardingiposition, and

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2502656 *Apr 18, 1944Apr 4, 1950Kett Tool CompanyPower-driven rotary hand guided cutting tool
US2987084 *Aug 15, 1960Jun 6, 1961Jarvis CorpPortable power saw
US3034493 *Jul 24, 1959May 15, 1962Bandy Charles RSuction sawdust collector
US3292673 *Aug 27, 1963Dec 20, 1966Rockwell Mfg CoPower operated portable hand saw
US3922785 *Nov 12, 1974Dec 2, 1975Makita Electric Works LtdSafety devices for electric circular saws
US4672746 *May 8, 1986Jun 16, 1987Christopher ZeilengaProtective mechanism for circular saws
US4856394 *Apr 14, 1988Aug 15, 1989Porter-Cable CorporationPortable circular saw
US5832614 *May 20, 1997Nov 10, 1998S-B Power Tool CompanyRemote lower guard lift lever mechanism for circular saws
US5873169 *Jun 25, 1997Feb 23, 1999Milwaukee Electric Tool CorporationBlade guard stop for a circular saw
US6415699 *Feb 25, 2000Jul 9, 2002Black & Decker Inc.Locking arrangement for table saw guard
US6662695 *May 20, 2002Dec 16, 2003Blacker & Decker Inc.Locking arrangement for table saw guard
US6893334 *Jan 24, 2003May 17, 2005J. David StiversRotating guard for angle grinder
US7055250 *Dec 23, 2002Jun 6, 2006Trumpf Grusch AgMachine tool for cutting plate and sandwich panels
US7426787Jun 15, 2006Sep 23, 2008Sj2 Industries, LlcRetractor for circular saw lower safety-guard
US7832072Jul 21, 2008Nov 16, 2010Sj2 Industries, LlcMethod of retrofitting a circular saw
US8413340 *Nov 2, 2010Apr 9, 2013John Michael OrlowskiSafety guard for power saw
US8998685 *Nov 29, 2011Apr 7, 2015C. & E. Fein GmbhGrinder having dust extraction system
US20020134211 *May 20, 2002Sep 26, 2002Marcello BettacchiniLocking arrangement for table saw guard
US20030075028 *Dec 21, 2001Apr 24, 2003Albrecht HofmannHand tool machine with a pivotable tool cover
US20030121390 *Dec 23, 2002Jul 3, 2003Marco AllemannMachine tool for cutting plate and sandwich panels
US20080271310 *Jul 21, 2008Nov 6, 2008Tracy Jack RMethod of retrofitting a circular saw
US20110099819 *Nov 2, 2010May 5, 2011John Michael OrlowskiSafety Guard for Power Saw
US20110162218 *Jul 7, 2011Andrew RoiseHand held circular saw power tool having multiple modes of operation
US20120135671 *Nov 29, 2011May 31, 2012Olaf KlabundeGrinder Having Dust Extraction System
EP0331036A2 *Feb 24, 1989Sep 6, 1989Karl M. Reich, Maschinenfabrik GmbHCircular saw with an integral base plate
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U.S. Classification30/391, 30/377, 451/456
International ClassificationB27G19/04, B27G19/00
Cooperative ClassificationB27G19/04
European ClassificationB27G19/04