US2659399A - Guard for portable power saws - Google Patents

Description

Nov. 17, 1953 J. v. DOUG 2,659,399

GUARD FOR PORTABLE POWER SAWS Filed Dec. 1, 1951 5,3 9 5 I g J6, 6 I 6 48 w v 59 JOE I! DOUG //VVENTOR F76. 5.- 60 35 l-IUEBNER, 955mm,

3/ 66 65 WORREL a HERZ/G 67 V ATTORNEKS- Patented Nov. 17, 1953 UNITED STATES PATENT OFFICE 6 Claims.

The present invention relates generally to portable power driven tools and more particularly to an improved guard for portable power saws.

Portable power saws have been found effective in minimizing the labor required in building construction and the like but have proved a source of such frequent injury to their operators as to substantially reduce their utility. In many instances the use of such power driven tools has been banned because of the excessive injury rate.

Such saws usually employ an electric motor having driving connection to a circular saw blade and are provided with a handle for portability. A housing is rigidly mounted on the motor in shielding relation to a portion of the blade usually enveloping substantially half of the periphery of the blade. The housing can be conveniently visualized as providing an edge from which the blade is extended approximately diametrically related to the blade. A guard is pivotally mounted on the housing for movement between a position in shielding relation to a portion of the exposed periphery of the blade and a position retracted therefrom so that in utilizing the tool the blade can be caused to transverse a board or the like while the guard is retracted from the blade. When so. employed, it is the usual practice for the o erator to guide the saw by means of the handle and by grasping the guard while pivoted into its retracted position. As it is sometimes necessary to apply considerable pressure in causing the saw to progress, sufiicient force is frequently imposed upon the guard to cause the articulately connected guard and housing suddenly to buckle, thrusting the operators fingers forcibly into the driven blade. Although such operation of portable power driven saws is generally forbidden, it has been found that the dangerous practice continues unless the saws are banned or substantially modified in structure.

An object of the present invention is to provide an improved guard for portable power driven saws and the like that is conducive to improved safety in the utilization of such tools.

Another object is to provide a guard of the character described providing a grasping handle so positioned as to preclude movement of an operators fingers into the saw blade even if the guard and housing on which it is mounted buckles in the described manner.

Another object is to provide an improved guard for power driven saws providing a handle which when grasped with the guard in closed position locks the guard in such position.

Further objects and advantages are to provide improved elements and arrangements thereof in a device of the character and for the purposes set forth that is economical to produce, fully eifective in obviating the described hazards incident to power saw operation, and that achieves improved safety characteristics Without in any way detracting from operational convenience.

Still further objects and advantages will become apparent in the subsequent description in the specification.

Referring to the drawing:

Fig. 1 is a side elevation of a portable power driven saw employing a saw guard embodying the principles of the present invention.

Fig. 2 is an end elevation of the saw and saw guard.

Fig. 3 is an enlarged fragmentary side elevation of the saw and saw guard with a cover for a latching mechanism shown in section, as viewed from line 3-3 in Fig. 2. v

Fig. 4 is a section of the latching mechanism of the movable guard, as taken on line 4-4 in Fig. 2.

Fig. 5 is a section through the latching mechanism, as viewed from line 5-5 in Fig. 3.

Fig. 6 is a section through the latching mechanism as taken on line 66 in Fig. 3.

Referring in greater detail to the drawing:

An exemplary portable power driven saw is illustrated in Figs. 1 and 2 of the drawing at 0. The saw is constructed with a housing i I having an upwardly and laterally extending handle 12 whereby the saw may be conveniently carried and manipulated during sawing operations. The housing 1! encloses an electric motor It having a drive shaft l4 extended axially endwardly therefrom. A circular saw blade i5 is secured concentrically to the shaft.

The sawis also rovided with a flat rectangular guide plate l9 whereby the saw may be guided along the surface of a board 20 while the board is being sawed to a desired dimension or shape. Although the saw illustrated is electrically powered, any power driven saw or other suitable tool may utilize the subject guard subsequently described without departing from the spirit or scope of the present invention. In order to protect operators of the tool, a guard 25 is rigidly mounted on, or constitutes an integral part of, the housing i I and encloses an upper portion of the periphery of the saw blade I8. The structure described to this point is essentially conventional and simply illustrates a tool in connection with which the guard of the present invention readily demonstrates its utility.

A movable guard 26 is mounted on the saw by forming an ear 30 on a portion of the fixed guard 25. The movable guard comprises a pair of concave guard members 3i which are bolted together, as at 32 in facing relation forming an open arcuate saw pocket 33 and a closed lever pocket 34. Each guard member 3| of the movable guard has an ear 35 extended endwardly therefrom with the ears in alignment transversely of the guard. A pivot rod '36 is passed axially through the singular ear 30 and the pair of ears 35 on the movable guard with the pivot rod pinned at 31 to the ear 30 on the housing" to prevent rotation therein and: with .the'ears:

31 rotatably mounted on the pivot rod.

An elongated arcuate handle 38 is formedinsubstantially concentric relation .to.the-saw.blade.

l having handle legs 39 at each end thereof whereby it is integrally connected to the movable guard 26. A finger recess 40 is formed between thehandle and themovable guard for receipt of the fingers of an operator during saw operations;

A movable guardwithout a handle has been employed in portable power driven saws before the improvement of the present invention. In the use of such saws without the handle attached to the movable guard, operators frequently grasp the saw guard Withthe described hazard and.

frequently resulting injury. A significant feew ture of the present invention is the provision or the handle in sufficiently spaced relation to the saw pocket 33 asto-preclude extension of an operator's fingers into theblade while grasping the handle.

The movable guard 26. is constantly urged to its pivotally closed position in shielding relation to the saw blade by securing a cup 42 to one-end of the pivot rod 36 and locating a torsion spring 43 in circumscribing relation .to the pivot rod with one end thereof anchored to theecup and its opposite end anchored to.the.-movable-.guard with the s ring under initial torque.

It.is desirable at times,- for carrying conven: ience and the like; tov prevent 2 relative pivotal movement betweenthe saw guard 26 and the saw housing II when the saw guard :is.in.its closed position shielding a'portion of theperiphery of the saw blade. Themovable guard is automatically latched, and may be manually unlatched, in closed position .by a latching mechanism indicated generally by the reference numeral 44. A boss 45 is formed integrally with thestationary saw guard 25 having aninnerface 46 concentric to the pivot rod 36. A frusto-conical'recess 41 is formed in the boss 45 extending inwardly of its face 46 relativelyradially outwardly of the pivot rod. A lug is formed axially of. oneear;

35 of the movable guard '25. A bore "is formed through the lug 48 radially of the.pivot rod-36 and in axial alignment withthe recess 41 when the movable guard is in its. closed position.

An elongated cylindrical latch pin 50 is mounted for longitudinal slidable movement in the bore 49. The'latch pin is provided with an enlarged annulus 5| which is longitudinally. slidable in a counterbore 52'formed in the lug 48 concentrically of the bore 49. A helical compression spring 53 is located under initial compression between the bottom of the counterbore 52 and the annulus 5| in circumscribing relation to the latch.

pin 50 continually urging the latch pin to aretracted position from the recess '41.

An elongated latchlever 55 is pivotally mounted between its ends on a pivot'pin' 51 extended through the members 3'! 'of themovableguard 25'. A manually operable grip end'58' of" the latch lever projects into the lever pocket 34 of the movable guard and has a portion thereof disposed in the finger recess 40 between the handle 38 and guard 26. An opposite pin actuating end 59 of the latch lever extends through an L-shaped slot 60 formed through the movable guard. An aperture 6! is formed through the end 59 of the latch lever through which one end of the latch pin 50 extends. A helical compression spring 62, of greater compressive resistance than the spring 53, is' located under initial compression in circumscribing relation to the latch pin between the pin actuating end 59 of the latch lever and the annulusof..the.-latch pin. The outer end of the latch pin is provided with external screw threads 'fif and a nut 64 is threaded thereon to maintaimthe; latch. lever and latch pin in as sembled relation and to provide manipulation oi thelatchpin on actuation of the latch lever.

In order to preclude interference with the actuation of the latch pin due to the presence of dirt and dust'therein, avsheet-metal cover 56 is preferably provided" for the movable portions 01 the latching mechanism; This cover. has a pair of ears through which screws 61 arepassed and.

engaged in the movable guard.

The innerface of the boss 45 on the housin is; beveled at 10 to. form an approachfor the latch pin .50 to guide thelatch pin inwardly-whenever the. movable guard is rotated to closed posiyond the-lug on inward pivotal movementoi the movable'guard the latch pin is cammed inwardly by thebeveled approach-" until thepin is in axial alignment-with the recess" in the.boss- Operation The operation and'utflity of the present inven tion are. believed.'to"be;. app arent and are. briefly summarizedat thispoint. 'I'heportable powe driven saw is adapted conveniently to;cut lumber to the desired. sizes and shapes witha substantial portion.of the periphery of the,saw blade IBshieldedby the fixed guard .25.. The movable guard 26 normally, is pivoted inwardly by the torsion spring 62 in shielding relation tothe lower portion of the periphery of the'saw. During sawing operations, the saw is manipulated by an operator grasping the handle l2 for manually guiding thesaw to desired. positions to attainthc proper saw cut. The guide plate I! may be rested on the upper surfaceof thepieceof lumber so that aconstant-depth of cut is maintained.

It.is sometimes desirable tocarry the saw by the handle. 38. In. such. instances, .the. operator simply grasps thehandlefln on themovable saw guard 26. With the hand in its naturalimsition. grasping. thehandle 38, the fingers .of that handextend through the fingerrecess so over the manually operable end.53. of'the latchziever 53. The manually operableend of the latch lever is thus depressed which forces the latch pin 50 into the .frusto-conical recess: 41' and precludes outwardpivotal movement of the saw guard. from its position in shielding relation to a portion of the periphery of the saw-blade. Although the helical compressionspringfl urges thelatch'pin to. retracted position, inasmuchas the spring 62 has a greater compressiveresistance than the spring 63, depression ot'the'manually operable end 58 of 'th'e latch lever movesthe actuatin end 59 of the latchle'verinwardlitoward the 5,. lug 4s thereby urging the latch pin so into the recess ll. Thus, as long as the handle 33 is grasped and the end 58 of the latch lever depressed, the saw guard can not pivot outwardly from rest position.

As the saw is initially'guided intoa piece of lumber to form a cut therein, the movable guard is located over a portion of the periphery of the saw. As the portable saw is moved along the piece of lumber during cutting operations, the leading edge of the lumber engages the inner edges of the movable guard pivoting the movable guard rearwardly around its pivot rod is until it reaches the position shown in dashed lines in Fig. l 01" the drawing. While the movable saw guard is in this rearwardly projected position,- the guard handle 88 is convenientlylocated to be grasped by the otherwise free hand of the user of the saw so that the saw may be guided more conveniently and more accurately than heretofore possible. Further, if the operator's thrust on the handle is excessive and the guard. 26 buckles on the housing H, the guard simply moves to closed position and, the operators hand being on the handle no hazard is encountered. Q

When the piece of lumber has been completely out and the saw blade i 5 moves free of the piece of lumber, the torsion springs 45- urgesthe movable saw guard back to closed position in shielding relation to the saw blade. 7

The device of the present invention is eoonorcb cal to produce, successfully obviates the described. and similar hazards incident to power tool operation, and provides auxiliary means facilitating accurate, safe and dependable operation.

Although the invention has been herein and described in what is conceived to be most practical and preferred embodiment, recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus.

l-laving described my invention what I claim as new and desire to'secure by Letters Patent is:

i. In combination with a portable power driven saw having a rotatable circular saw blade and a fixed guard enclosing a portion of the blade with a peripheral portion of the blade extended from the fixed guard for work piece engagement, a pivot rod rotatablv mounted in the housing in axial parallel relation to the blade, an elongated arcuate guard having a concave edge formed with a channel longitudinally thereof and an opposite edge, said arcuate guard being mounted in fixed radial position on the rod for pivotal movement upon rod rotation between a closed position with the channel fitted over the extended periphery of the blade and an open position retracted from the blade, a handle integral with the arcuate guard having a grip portion in spaced relation to the edge of the guard opposite to the arcuate edge and defining a finger recess therebetween, said grip portion having a groove formed therein disposed toward the arcuate guard, the fixed guard having a bore formed therein adjacent to the rod, an elongated latch pin mounted for longitudinal reciprocal movement in the rod in alignment with the here when the arouate guard is in closed position, a compression spring urging the pin into a. position retracted from the bore, a latch lever pivotally mounted in the handle with an operating end positioned in the groove of the grip and an actuating end provided with an opening slidably receiving the latch pin, and a compression spring mounted on the latch pin having an end in abutting engagement with the actuating end of the latch lever.

2. A portable saw comprising a power driven blade, at fixed guard mounted in housing relation to a portion of the blade, a handle rigid with the fixed guard for manually urging the saw blade in a predetermined direction in the plane of the blade through work pieces to be cut, and a safety guard pivotally mounted on the fixed guard rearwardly of the blade relative to the predetermined direction of movement thereof for pivota1 movement between a position extended forwardly from its pivotal mounting, and a position extended rearwardly therefrom, said safety guard having an edge fitted over the blade in its forward position which edge is adapted slidably to rest on a work piece being sawed when in its rearward position, said safety guard having a handle integral therewith in spaced relation to the edge fitted to the blade and having a finger recess between said handle and safety guard for auxiliary urging of the blade through work pieces when the guard is in rearward position.

- 3. A portable saw comprising a power driven saw blade having an upwardly disposed periphery and a downward disposed periphery engageable with a work piece, a fixed guard fitted downwardly over the upwardly disposed periphcry of the saw blade, an upwardly disposed handle adapted for motivation of the saw in a predetermined direction relative thereto over a work piece, whereby the fixed guard has forward and rearward end portions, a safety guard pivotally mounted on the rearward end portion of the fixed guard and downwardly and forwardly extended therefrom below the saw blade and having an edge fitted upwardly over the lower periphery or the saw blade, said edge or the safety guard being slidably engageable with a work piece being sawed by the blade upon forward movement of the saw to cam the safety guard into a rearwardly and upwardly pivoted position slidably rested on the work piece, said safety guard having a handle integral therewith oppositely disposed from the saw guard relative to the blade and defining a finger recess between the handle and the guard in spaced relation to the edge of the guard fitted upwardly over the blade whereby a workmans hand grasping the handle on the safety guard is at all times spaced from the saw blade independent of the pivotal positioning of the safety guard and auxiliary motivation of the saw by means of said handle made possible when the safety guard is slidably rested on a work piece.

4. In combination with a portable power driven saw having a guide plate slidable over a work piece to be sawed, a motor mounted on the guide plate, a saw blade connected to the motor having a periphery extended below the guide plate for work piece engagement, a fixed guard mounted on the motor and fitted downwardly over the saw blade terminating in upwardly spaced relation to the guide plate, and a handle mounted on the motor adapted for manual urging of the guide plate, motor, blade, and fixed guard in a predetermined direction relative thereto over a work piece whereby the fixed guard has a forward and a rearward end portion; a safety guard pivotally mounted on the rearward end portion of the fixed guard forwardly extended beneath the guide plate and fitted upwardly over the 1am;- peripnery: ofxthn'i saw. bide; slfli: guard: having a handle: intesnii therewitlh on positeiy disposed: from: thez safetyrglls'lhtm the sawzbhde providing an; flngenrecesszxbetm the:

handle and the guard in spacedzreiationztosthe': 5%

saw blade; the: may guard:v being: rearwnrdiy and upwardly pivotaitoiairearwardbw'rdeed'zm sitiontwithaall portions thereof'rabowe'z'tlimgikieit plate: and havinga'zsaw blade. receivimcedwz'en'q gageable with a work"pieoeiforciblywtofpivot' the? v thedower mripheral portion safety guard rearwardly and "upwardh'z-uponxfofi ward movement of the saw and an.. extended Henri adapted to rest upon and slide over a workpiece? when the 'safety guard is rearwardlyiand' upward; I

1y pivoted with the'handlevupwardly'dispoeediorgrasping and' auxiliary motivation oftlie-satr 51- In' combination with a; portable-saw ham a" power driven saw'blade'havingamupwardfi disposed periphery and a' downwardly periphery engageable' with a workpieee,- eflfi'iied' 207' guard fitted downwardly over the upwardly di's posed periphery of the saw'blade; arr-upwardly disposed handle adapted for motivation of thesaw in a predetermined direction relative'tl'iemto over a work piece whereby the fixed guard nae' forward and rearward end portions; a safetyguard pivotally mounted on the reerward' 'end portion of the fixed guard and downwardli and forwardly extended therefrom below the saw" blade and h'aving an-edgefittedupwardly crease the lower'periphery of the saw blade, said edge of the-safety guard being slidably engageahle with a work piece sawed by the blade upon forward movement of the saw'to'cam'th'e safety gnard into a rearwardly and upwardlyplvoted position slidably rested on the workpiece; said safety guard having ''a handle integral therewith oppositely disposed fromth'esaw guardrelative to the bladea-nd defining afinger 'recesebetween the handle and'the guard'inspaoed relation to"40 the edge of the:guard" fittedupwardly over the' blade whereby a work'mansihand grasping-tiie; handle on the safety guard is at 'alltir'nesmpaeedf from the saw blade independent'of 'the' positioning of the safety guard" and auxiliary 5:

urging the safety guard into its forwardiy*efi-= oi tended position fitted-upwardly over the'flowet periphery of the saw blade;

6. In combination .with'a portable power driven; saw having a guide plate slidable arena-work:

piece to be sawed; a. motor :mountedzonthe'gnider plate; a saw' bladevconnecteduto: theamotorzhlaw ing a peripheral portion .extendedxbeiowvthe plate for work piece engagement; a"-fixed;:guardf; mounted .on .the -motor and downwardly 8- on: I'M m in: upwardly) .and a handle atone-darned Grim-mill urg+- and fixed guard in a predetermined direction relative tlardumerumrhueoemehy the fixed guard hissaxfdnmtiamaamrdmndportion; a sfldtyzmmmron :the: rearward enlt 'pmtim'nfdihe'fikedaundiorwardly extendedfibeneeshitheagnidt date and having. an edge offtho lfiademaidrelicty miard'having a handi'ezintegrai oppositely disposed from the l sdfltyrfflll'dfim blade providing a finger-:reoeusbetneemthe hmdieandtheguard in: armed erebtionztmthmsaw'blade, the safety pivotal to a rdsedsmsition with all portions thereofz'abbvewthmgniderpiate and .the saw blade meme. with a. work pieeezmdsshamdtsotasito' cam ;the' safety guard and immdiy: upon: forward vmovementiofz'thrsaw mdithe ,sdetyguard having an extended endadapteditorst upon and slide over a m pteeezwhenzthesafety guard is rearwardly and umdlyzpivoted withz'the handle upwardly disposedi for: auxiliary motivation oi: the resilient :means interconnecting the safety: guard:v and: theafind guard urging the safety guard into its .fomrdiy extended position flttetlmdbi m' thtlm peripheral portion of'theisaw-e'blade; aaiateh 11:: mounted for iongitudmaireeiprocai movementitoward and from thermal." guard: pivotal movement with the :safetyreuard; therfixed-rguard having a borezthereimadaptedto reeeiverthe' pin when the safety isi'fittodzimmdly over the lower peripheral aportiowottb guardpresiiient means urgingthefpinrintoapnsition retracted from the bore;- a latcir'ilemzpiwtallxmounted in the handiemfrl'thefssie'tyrgnard;md disposed for finger mi -1111M. recess; and resilient means inteeoomeeting-ztheeleverland the pin urging the pin toward the fixed guard in response to pivotal movemt od the handle.

JOE V. DOUG.

Euler-m '-Cited.- in thel 'file of this patent UNITED #S'I'ATES PATENTS Number" Name Date Oct. 4, 1927' 1,7403%" Crowe Dec. 17, 1929 2,346,901 Gimdlfihger etal. Apr. 18, 1844

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