US3331409A - Slidable guard and gauge for portable power saw - Google Patents

Description

July 18, 1967 E. REED ETAL 3,331,409

SLIDABLE' GUARD AND GAUGE FOR PORTABLE POWER SAW Filed June 29, 1965 2 Sheets-Sheet l i /IS 3 5 6! l I r N. I g 66 mum" NVENTORS! CHARLES REED 2,

Y HOLLIS E REED r f 2. Arrow/ x5.

y 18, 1967 c. E. REED ETAL 3, 31, 09

SLIDABLE GUARD AND GAUGE FOR PORTABLE POWER SAW Fild June 29, 1965 2 Sheets-$heet 2 INVENTORSI CHARLES E. REED 7 1 BY HOLLIS E. REED 3,331,439 Patented July 18, 1967 3,331,409 SLIDABLE GUARD AND GAUGE FOR PORTABLE POWER SAW Charles E. Reed, Morgan Hill, and Hollis E. Reed, Santa Clara, Calif., assignors of one-third to Anton J.

Zupancic, doing business as Micro Manufacturing Company, Santa Clara, Calif.

Filed June 29, 1965, Ser. No. 467,867 7 Claims. (Cl. 143-159) This invention relates to an attachment for power saws and more particularly to a slidable guard and gauge for the blade thereofv The main purpose of the attachment embodying the present invention is to provide a safety guard on the open side of the blade housing. In framing a house it is a common practice to pre-cut the wall studding lumber to uniform length lay them out on 'a flat surface 16 inches on center and then nail them to top and bottom wooden plates. The studding thus formed is next raised and placed to stand vertically where desired as wall framing of which the bottom plate is nailed to the sub floor. Thereafter the continuous framing is marked and cut out where door openings are to be formed as planned. Heretofore the bottom plates were cut out by hand saw, the cross cut through the plate usually being made along one vertical face of an upright stud against which an additional two by four is later set and nailed to provide a double buck. This double buck runs from the rough floor up to where a lintel is to be placed and nailed to form the head of the door opening.

Power saws are now being used in place of hand saws wherever possible but it is mandatory that such power saws have safety guards over the circular blades to prevent accidents or injury to the workmen. By removing the guard from a power saw and insetting the securing bolt of the blade it is possible to cut bottom plates flush with one face of a two by four stud where a door is to be formed. Such use of a power saw with its blade unguarded is prohibited by safety regulations under established State labor laws and violations of such regulations result in fines against contractors.

It is an object of the present invention to provide an attachment for power saws constructed to provide a sliding guard for covering the circular blade but permitting flush cut of the bottom plate of wall framing adjacent one of the studs thereof.

It is another object to provide a portable power saw with a sliding carriage operatively associated with a base casting providing a guide track for the carriage and a support for a blade cover which functions as a gauge with the base casting for positioning the tool incident to the cutting operation.

It is yet another object of the present invention to provide a sliding carriage for a portable power saw and means for guiding the same for sliding movement over a member to be cut. In this connection the guiding means serves as a gauge abuttable with the member to be cut and for positioning the saw normal thereto for accomplishing a square cross cut therethrough.

It is still another object to provide yieldable means for normally positioning the blade of such power saw behind a cover plate. Such yieldable means serving both the depth of cut as well as the stroke of cut between the carriage and the guide track whereby the saw :blade is at all times concealed safely behind the cover except during its cutting action.

These and other objects and advantages of the present invention will become apparent from a reading of the following description and claims in the light of the accom panying drawings in which:

FIG. 1 is a fragmentary perspective view of wall framing showing a power saw having the attachment of the present invention thereon facilitating a flush cut through the bottom plate of the studding.

FIG. 2 is an end view of the power saw and attachment of FIG. 1 as seen from the opposite end thereof.

FIG. 3 is a fragmentary perspective view of parts of the attachment, broken away and partially disassembled for purposes of illustration.

FIG. 4 is a side elevation of FIG. 2 as seen from the right hand side thereof.

FIG. 5 is a plan view of FIG. 4.

FIG. 6 is an exploded perspective View of the blade and mounting therefor to facilitate a flush cut.

Referring to the drawings, and particularly FIGS. 1 through 4 thereof, a frame structure 10 for a wall is shown as consisting of a plurality of studs 11 nailed to a base plate 12 from the bottom thereof and arranged to stand erect from a rough floor F to which the base plate 12 is secured by nails.

The device 13 of the present invention comprises a conventional power saw designated 15 having an attachment 16 arranged therewith in such a manner that the blade 17 of the saw can cut crosswise through the base plate 12 in a plane common to one vertical face 18 of a stud 11.

The saw 15 which is of conventional design has an arm 20 extending forwardly from its motor housing 21. This arm 20 is usually pivotally connected to an adjustable plate (not shown) to afford angular adjustment of the housing 21 relative to such plate to change the depth of cut of the :blade 17. In accordance with the present invention the adjustable plate is removed and a carrier plate substituted therefor. The arm 20 is pivotally connected by means of a pin bolt 22 extending between a pair of ears formed on a trunnion pad 23 secured to the fore end 24 of the carrier plate 25. The aft end of the motor housing 21 is disposed to rest upon a compression spring 2r mounted on a bolt 27 which extends up from the plate 25 and into the bottom open end of spring 26. The upper end 28 of the spring 26 is lodged in a suitable recess or the like formed in the motor housing 21 so that the spring 26 normally urges the housing 21 upwardly, in a clockwise direction FIG. 4, about the axis of the pin bolt 22.

The aft end of the motor housing 21 has the usual handle grip 30 one lower arm 31 of which engages a hook 32 extending up from the carrier plate 25 for limiting movement of the housing 21 away from the plate 25 under influence of the compression spring 26.

The carrier plate 25 is arranged for sliding movement in a guide track 33 formed in a casting 34 having a pair of foot blocks 35-36, which extend laterally from a vertical spine 37. Each foot block 3536 has a milled upper surface 38 disposed at a horizontal plane slightly above the upper surface of the bottom or base plate 12 of the wood frame to be treated. In other words, when the casting 34 is at rest upon the rough floor to which the base plate 12 is secured, the foot blocks 35 and 36 stand at substantially the same height as the base plate 12. In this manner the carriage plate 25 is supported upon the foot blocks 35 and 36 for sliding movement over the top surface of a base plate 12 which is to be cut.

The casting 34 has one upstanding milled surface 39 on its vertical spine 37 disposed for sliding surface engagement with one edge 40 of the carrier plate 25. The aft foot block 36 cooperates with a lateral projection 41 which overlies the carrier plate 25 so that the milled surface 38 of the block 36 and surface 39 of the spine 37 forms a C shaped guide 42 with the under surface 43 of the projection 41.

Each of the foot blocks 35 and 36 extend from the guide surface 39 of the spine 37 a distance comparable to the width of the carriage plate plus a slight clearance. The

outer end 44 of each foot block 35-36 has vertically aligned tapped bores 45 formed therein. These bores 45 are to receive the threaded ends of stud bolts 46 which extend through vertically aligned slots 47 in metal clips 48. The metal clips 48 have their upper ends bent inwardly to overlie the carriage plate 25 for maintaining the latter in sliding relation to the casting 34.

The former cover guard for the blade 17 is no longer required and has therefore been removed. This leaves the blade 17 fully exposed at one side of the housing of the saw 15. By reason of the manner in which the saw 15 is mounted on the carrier plate 25, the blade 17 is disposed outside and adjacent the back face 49 of the spine 37 of the casting 34. The after end 50 of the casting 34 has a face 51 offset outwardly from the back face 49 of the spine 37 and lies in a vertical plane substantially congruent to that of the outer face 52 of the blade 17.

A cover plate 53 is secured by means of screws to the face 51 at the after end 59 of the casting 34. This cover plate 53 extends forwardly from the after end 50 of the casting 34 and overlies the blade 17. The forward end 54 of the cover plate 53 terminates at the forward face 55 of the casting 34 which is also the forward face of the forward foot block 35.

Since the blade 17 must move freely adjacent the cover plate 53 there can be nothing projecting beyond the outer face 52 of the blade. Consequently, mounting of the blade 17 on the drive shaft 56 of the power saw 17 must be changed to correspond to the illustration in FIGS. and 6 of the drawing.

As shown in FIG. 6 a mounting flange 57 of diameter of approximately one quarter that of the blade 17 is mounted on the drive shaft 56. This flange has a recessed center 58 to accommodate a securing nut 59 and a ring shim 60 thereafter placed in the recess affords a flat mounting surface along with the outer face 61 of the mounting flange 57. The outer face 61 has a plurality of tapped bores 62 aligned with comparable bores 63 in the saw blade 17. The bores 62-63 are countersunk to receive the heads of screws 64 by which the blade 17 is secured to the mounting flange 57.

By the foregoing arrangement the blade 17 is completely guarded by the cover plate 53 when the carrier plate 25 is drawn back relative to the guide track 33 of the casting 34. The carrier 25 is drawn back by a tension spring 65 having one end secured to a pin 66 on the trunnion pad 23 and its opposite end secured to a pin 68 on the projection 41 above the aft foot block 36 of the casting 34. Backward movement of the carrier 25 relative to the casting 34 under the influence of the tension spring 65 is limited. This limit is caused by a notched portion 69 on the forward end of the carrier 25 engaging the forward face 55 of the spine 37. Thus it will be noted that when the device stands free i.e. out of hand the blade 17 is covered, i.e. not exposed, and elevated above the lower surface 70 of the casting 34 by the compression spring 26 which elevates the power saw housing, as hereinbefore explained. V V

7 Having thus described the structure and arrangement of the guard and gauge of the present invention its use and operation is as follows:

The workman grabs the handgrip 30 in the usual manner and the parts assume the position illustrated in FIGS. 4 and 5 of the drawing. The entire device 13 is then placed on the rough floor with the forward face 55of the casting abutting a base plate 12 to be cut. The forward face of the forward foot portion 35 likewise engages the base plate 12 and serves to square the blade 17 with respect to the base plate 12. Note that the forward end of the carrier plate 25 extends beyond the forward face 55 of the casting 34 and foot portion 35. Also note that the foot portions 35 and 36 have their upper milled surfaces 38 disposed in a horizontal plane approximating theupper surface S of the base plate 12 to be cut. By shifting the device 13 toward a stud 11 and aligning the inner face 71 of the cover plate 53 with the face 18 of the stud the blade 17 is now in a position to cut a kerf K crosswise through the base plate 12 and at the vertical plane of the face 18 of the stud 11. V

The workman now pushes on the handgrip 30 to thereby cause the power tool 15 and carrier plate 25 to slide forwardly in the guide track 33 and against the action of the tension spring 65 relative to the casting 34. Since the periphery of the teeth on the blade 17 is slightly above the lower surface 70 of the casting 34 a slight downward pressure upon the handgrip 30 depresses the compression spring 26 enough to lower the blade to the floor. The pivot connection between the pin 22 and trunnion ears 23 together with the vertical side 32 of the hook 32 serve as a guide in the up and down movement of the power tool 15. a

In this manner, the casting 34 and cover plate 53 secured thereto remain stationary, i.e. in abutment with the studding, while the carrier 25 and power tool 15 move through the studding as illustrated in FIG. 1. Thus the blade 17 cuts a kerf K through the base plate 12 on the same plane as the face 18 of the stud 11 engaged by the forward edge of the cover plate 53. When the cut is completed and the entire device lifted, the tension spring 65 immediately contracts bringing the casting 34 and cover plate 53 back into normal relation to the carrier 25, power saw 15 and blade 17 It will therefore be appreciated that the blade 17 is at all times covered except for the brief moment during which the cut is made and then only partially exposed beyond the upright stud 11 adjacent which the cut is made.

While we have explained our sliding guard and gauge for a portable power saw in specific detail it will be appreciated that the same may be susceptible to modification, alteration and/ or variation without departing from the spirit of our invention therein. We therefore desire to avail ourselves of all modifications, alterations and/ or variations as fairly come within the purview of the ap- V pended claims.

What we claim as new and Patent is:

1. A guard for the exposed blade of a portable power saw facilitating a cross cut through the base plate of wall framing flush face to an adjacent stud comprising a base having a guide formed therein,

a saw carriage arranged for sliding movement in said guide,

means on said carriage for pivotally mounting such power saw thereon for up and down movement relative thereto and for movement therewith beyond the fore end of said base,

a cover plate mounted on the after end of said base and extending forwardly therefrom adjacent the outer face of the blade of said power saw to provide a guard slot open at its fore end,

and a tension spring between said base and said carriage for drawing the latter into a normal relation desire to protect by Letters wherein said blade is concealed behind said cover plate. 2. A guard saw facilitating a cross cut through the for the exposed blade of a portable power base plate of wall framing flush with one face of an adjacent stud comprising movement relative'thereto and for movement there-' with beyond the fore end of said base,

a cover plate mounted on the after end of said base and extending forwardly therefrom adjacent the outer face of the blade of said power saw to provide a guard slot open at its fore end and to provide a fore edge on said cover plate alignable with such one. face] of an adjacent stud to align the saw blade therewith,

and a tension spring between said base and said carriage for drawing the latter into a normal relation wherein said blade is concealed behind said cover plate.

3. The combination with a portable power saw having its blade exposed at one side to facilitate a flush face cut through the base plate adjacent one face of an upright of wall studding, a guard and gauge attachment comprising a main casting having a guideway formed therein,

a saw carriage mounted in said guideway and supported thereby for sliding movement over the top surface of such base plate,

means for pivotally connecting such power saw to said saw carriage with the blade of said saw exposed at one side of said casting,

means between said saw carriage and said power saw for yieldably urging the latter upwardly about its pivotal connection with said casting to thereby maintain the periphery of the saw blade above the lower surface of said casting,

means on said saw carriage engageable by said power saw for limiting upward movement thereof relative to said saw carriage,

a cover plate mounted on said casting in spaced relation to the saw blade providing a slot for concealing the latter and open at its fore end to expose the periphery of the blade, for movement toward a base plate to be cut,

and a tension spring between said casting and saw carriage for drawing the latter and the power saw carried thereby back into a position in which the saw blade is concealed behind said cover plate.

4. The combination with a portable power saw having a circular blade exposed at one side for cross cutting through a base plate of wall framing adjacent a stud member thereof, a guard and gauge for such saw blade comprising a base casting having a spine and a foot portion extending laterally therefrom to provide a guide track having its upper surface disposed in a plane substantially at the upper surface of such a base plate,

a saw carriage slidably mounted on said guide track for movement over such base plate,

means for pivotally mounting the fore end of such power saw on the forward end of said saw carriage with the saw blade disposed on that side of said spine opposite to said foot portion,

a compression spring between said saw carriage and the after end of said power saw for yieldably supporting the latter in a position wherein the periphery of the saw blade is above the lower surface of said base casting,

said base casting having an after portion offset outwardly from said spine,

a cover plate secured to the after portion of said base casting to overlie and cover the blade of the power saw and extending forwardly to a plane common to the forward face of said foot portion for abutting the base plate and a stud of the wall framing to thereby position and align the saw blade to cut across such base plate flush to one side of the stud engaged by said cover plate,

and a spring between said base casting said saw carriage for drawing the latter back into a position wherein the saw blade is concealed behind said cover plate other than during cutting of a base plate.

5. The combination with a portable power saw having its circular blade exposed at one side thereof to make a cross cut through the base plate of wall framing adjacent a stud member, a guard and gauge for such saw blade comprising a base casting having a spine from which fore and aft foot portions extend laterally to provide a guide track having its upper surface disposed in a plane substantially at the upper surface of such as base plate,

a saw carriage mounted in said guide track for sliding movement in a fore and aft direction relative to said base casting and over said base plate,

means on the forward end of said saw carriage for pivotally connecting the fore end of such power saw to said saw carriage with the saw blade exposed on that side of the spine of said base casting opposite to said foot portions,

a compression spring mounted on said saw carriage in the region of the after end of the power saw for yieldably supporting the latter in a position to maintain the periphery of the saw blade thereon above the lower surface of said base casting,

said base casting having an after portion offset outwardly from said spine,

a cover plate secured to the after portion of said base casting to overlie and cover the blade of the power saw,

said cover plate, spine and forward foot portion each having forward faces in a common plane for abutting the wall framing base plate and a stud to thereby position the saw blade to cut across such base plate flush to one side of the stud engaged by said cover plate,

and a tension spring between said saw carriage and said base casting for drawing them together to maintain the saw blade behind said cover plate other than during cutting of a base plate.

6. A guard for the exposed blade of a portable power saw for cutting a base plate flush face to an adjacent stud comprising a base having a guide formed therein, a saw carriage arranged for sliding movement in said guide, means on said carriage for pivotally mounting such power saw thereon for up and down movement relative thereto and for movement therewith relative to said base, a cover plate mounted on said base adjacent the outer face of the blade of said power saw, said base and cover plate each having a fore edge in a plane to engage the base plate and stud, respectively, to square the saw blade relative to the base plate and align the saw blade with one face of the stud, and a tension spring between said base and said carriage for drawing the latter into a pormal relation wherein said saw blade is concealed behind said cover plate.

7. A guard for the exposed blade of a portable power saw for cutting a 'base plate flush face to an adjacent stud comprising a base having a guide formed therein, a saw carriage arranged for sliding movement in said guide, means on said carriage for pivotally mounting such power saw thereon for up and down movement relative thereto and for movement therewith relative to said base, a cover plate mounted on said base adjacent the outer face of the blade of said power saw, said base and cover plate each having a fore edge in a plane to engage the base plate and stud, respectively, to square the saw blade relative to the base plate and align the saw blade with one face of the stud, a tension spring between said base and said carn'age for drawin the latter into a normal relation wherein said saw blade is concealed behind said cover plate, and stop means on said carriage engaging said base for limiting relative movement between them under the influence of said tension spring.

References Cited UNITED STATES PATENTS 2,59 6,524 5/ 1952 Bridwell.

2,819,742 1/1958 Blachly.

3 ,045,724 7/ 1962 Mitchell.

3,221,583 12/1965 Nichols et a1. 143159 WILLIAM W. DYER, JR., Primary Examiner. W. D. BRAY, Assistant Examiner.

Claims (1)

1. A GUARD FOR THE EXPOSED BLADE OF A PORTABLE POWER SAW FACILITATING A CROSS CUT THROUGH THE BASE PLATE OF WALL FRAMING FLUSH FACE TO AN ADJACENT STUD COMPRISING A BASE HAVING A GUIDE FORMED THEREIN, A SAW CARRIAGE ARRANGED FOR SLIDING MOVEMENT IN SAID GUIDE, MEANS ON SAID CARRIAGE FOR PIVOTALLY MOUNTING SUCH POWER SAW THEREON FOR UP AND DOWN MOVEMENT RELATIVE THERETO AND FOR MOVEMENT THERWITH BEYOND THE FORE END OF SAID BASE

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