US1932511A

US1932511A - Motor driven hand tool

Info

Publication number: US1932511A
Application number: US139271A
Authority: US
Inventors: Alex A Clarke
Original assignee: ALEX A CLARKE; THOMAS B BENNETT
Current assignee: ALEX A CLARKE; THOMAS B BENNETT
Priority date: 1926-10-04
Filing date: 1926-10-04
Publication date: 1933-10-31
Anticipated expiration: 1950-10-31

Description

0a. 31, was. A A LARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4. 1926 5 sheets-sheet 1 A. A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 5 Shegts-Sheet 2 'HHQQ'IWW" Oct. 31, 1933 A. A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL 7 Original Filed Qct. 4, 1926 5 Sheets-Sheet 5 n um i iwllhl Oct. 31, 1933. A. A. CLARKE 1,932,511

' MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 5 Sheets-Sheet 4 #ZZZZ JQ I J1 Oct. 31, 1933.

A. A. CLARKE 1,932,511

MOTOR DRIVEN HAND TOOL Original Filed Oct. 4, 1926 s Sheet-Sheet 5 1 Hm II m m m IIIH um, 11 I Patented Oct. 31, 1933 UNITED STATES PATENT OFFICE MOTOR DRIVEN HAND TOOL Alex A. Clarke, Chicago, Ill., assignor to Thomas B. Bennett, Muskegon, Mich.,

jointly and himself Application October 4, 1926, Serial No. 139,271 Renewed August 17, 1932 23 Claims.

to permit convenient and accurate guidance thereof by the hand of an operator during the cutting operation-and to constitute a stable, substantially self-supporting structure; the combination of the tool with a base arranged to bear on the work to be cut and so related to the tool as to fully define the character of the cutting operations in respect to the depth of the cut, and the angle thereof; an adjustable joint between the base and the cutting tool for co-relating the direction of the movement of the cutting disk with respect to the movement of the base; the utilization of the base as a guard protecting the operator against accidental contact with the cutting blade when the tool is out of operation; gauge means associated with the tool for predetermining the depth of the cut and the angular relation thereof to the piece to be cut, and for performing special cutting operations; indicating means associated with said tool for conveniently determining the cutting adjustments; the utilization of the ventilating arrangement of the electric driving motor of the tool for removing the waste particles produced by the cutting tool from near the cutting edge thereof; and other features that will appear more fully from the following specification and claims, taken in connection with the accompanying drawings in which,

Fig. 1 is a longitudinal vertical sectional view of a motor-driven hand saw made according to my invention;

Fig. 2 is a fragmentary elevational view of the tool handle, showing the locking arrangement and indicator for determining the angularity of the cut; 1

Fig. 3 is a top plan of the tool, a portion of the power transmission housing being broken away to show the interior arrangement thereof;

Fig. 4 is a sectional view through the device shown in Fig. 1 along the line IVIV;

Fig. 5 is a transverse sectional view through the fan housing and handle of the motor along the lines V-V in Fig. 1;

Fig. 6 is an elevational view of the cutting tool, from the back of Fig. 1;

Fig. '7 is a plan view of the base guide of the toolshown in Figs. 1 to 6 for predetermining the direction of the cutting operation and the adjustment for miter cutting;

Fig. 8 is a view partially in section, and partially in elevation, of the gauge and indicator for 0 determining the depth of the cut, combined with 'means for resiliently projecting the base away from the cutting disk to serve as a guard therefor;

Fig. 9 is an end-elevational view of the tool 5 from the front thereof while engaged in making an angular cut;

Fig. 10 is a plan view of the tool as shown in Fig. 9, while making a cut that is straight with respect-to the edge of a board but under an angle against the surface thereof;

Fig. 11 is a view similar to Fig. 10, showing the tool engaged in making a miter cut, also under an angle against the surface of the work-piece;

Fig. 12 is a view similar to Fig. 1 of an arrangement embodying a modification of my invention;

Fig. 13 is an end elevational view of the tool shown in Fig. 12, from the back thereof, with the base provided with a ripping-gauge attachment;

Fig. 14 is a fragmentary-plan view of a portion of thebase and the associated ripping gauge attachment shown in Fig. 13.

In Figs. 1 to 11 is shown an embodiment of my invention which includes a power-driven tool unit comprising a motor unit 1, having substantially rigidly attachedthereto a tool holder, or carrier, and transmission-housing unit 2, in which is mounted a cutting disk or saw 3. These several units are so associated with a hand grip or handle 4 and a base 5 for supporting and guiding the tool on a work-piece, such as a board 6, as to secure a cutting tool of universal utility, capable of performing all operations in which it was heretofore necessary to use a number of hand driven cutting tools, or large power driven machines. The arrangement of the several parts constituting my improved cutting tool is such that it is capable of performing by means of electrical power drive the operations of hand driven saws, with a high degree of accuracy, and in predetermined adjustable relation to the piece to be worked. The various operations are carried on by my improved tool with very great speed, and the several parts thereof are so arranged as to secure a stable support and guidance during the operation of the tool and throughout the handling thereof, with substantially entire elimination of the danger of injury to the operator or other objects in the neighborhood of the tool.-

Thehigh degree of stability of my improved tool and the ease of handling the same is to a large extent secured by the particular grouping of the motor unit 1 and the tool housing 2, with the tool 3, in front thereof, and the handle 4, so related thereto that the masses are so distributed as to be substantially in equilibrium, and self-supporting when brought in contact with a work-piece. The tool so constructed requires little, or no, efiort on the part of the operator while handling the same. In view of the very dangerous character of power-driven circular saws, the elimination of the hazard to the operator, by the above described arrangement of the several parts constituting the tool unit, not only facilitates the actual work that is to be performed but by removing the metal hazard usually associated with danger, it enables him to perform more work with greater accuracy and skill.

The details of the structure of my improved tool appear clearly in the accompanying drawings. The motor unit 1 comprises a small powerful electric motor 11, of familiar design, having a rotor 12 provided with a driving shaft 13 journaled in suitable bearings 14 held in the end members 15 of a tubular motor housing 16. In the position shown in Fig. 1 of the drawings, illustrating the tool engaged in cutting a board 6, the motor axis and shaft 13, with the associated housing 16, are inclined, the forward ends thereof pointing downwardly in the direction in which the cutting operation proceeds.

Extending directly away from the front end of the motor housing 16 is mounted the tool housing on carrier frame 2, and the circular cutting tool or disk saw 3, the frame being so shaped that the circular cutting disk 3 is preferably in substantial alignment with a medial plane through the axis of the motor 11. In the position shown in Fig. 1 the cutting disk is disposed in a vertical medial plane through the motor 11.

The tool carrier 2 has a tubular frusto conical flange member 21 for rigidly securing the same to the front end of the motor housing. The narrow end of the flange member 21 constitutes a neck 22 fromone side of the center of which extends a substantially semi-circular wall 23 disposed on one side of the circular cutting disk for supporting the same and guarding one side thereof. The periphery of the semi-circular tool guard and supporting wall 23 has a laterally extending circumferential guard rim 24 overlapping and protecting the upper portion of the circumference of the cutting disk 3.

The cutting disk 3 is detachably mounted, at its center, on a shaft 26 which is journaled in bearings 2'] held in the walls of a transmission casing or housing 28 laterally extending from the guard wall 23 on the side opposite the saw disk 3. The transmission casing 28 constitutes an elongated chamber extending substantially parallel to the axis of the motor and encloses the power transmitting mechanism comprising a gear wheel 31 fixed to the front end of the motor shaft 13, to drive a pinion 32 secured to one end of a counter-shaft 33, the other end of which is provided with a worm 34 for driving a worm wheel 35 mounted on the disk shaft 26 for rotating the disk 3. In order to suitably support the counter-shaft 33 and the associated gearing mechanism 32, 34, 35, ball bearings 36 and the bearings 2'? are suitably held in wall portions of the transmission housing 28, the latter diyiding into a number of distinct chambers surrounding the individual parts of the transmission mechanism.

For the successful operation of a hand guided motor driven tool of the type here considered it is of utmost importance that vibrations incident to the operation of power transmission mechanisms should be eliminated. The tool carrier and the associated transmission housing shown a in the drawings have been designed with particular view to elimination of any possible sources of vibrations that might be caused by misalignment of the individual parts. To this, end the transmission housing 28 and the tool guard and carrier 23, 24, are preferably made in the form In the form of the casting shown in the draw ings, the seating surfaces for holding the bearings 36 which support the counter-shaft 33, may be machined from the two open ends of the housing, one end being on the side of the flange 21 by which the tool carrier is held against the motor housing, the other opening being-at the opposite end of the longitudinal chamber, which opening, in the assembled completed tool, 3 is enclosed by a suitable cover 37.

The seat surface for the inner ball bearing 27 which holds one end of the disk shaft 26, is

similarly machined from an opening in the part of the transmission chamber surrounding saidshaft on the side opposite the saw, said opening being enclosed by a suitable cover 39 which has a seat member for the outer disk, shaft bearing 27.

The entire structure may be stiffened by suitable ribs 40 extending between the several parts of the tool carrier frame. The handle 4 for holding the tool unit, mentioned before, is preferably made as an integral part of the motor housing 16, and, as pointed out above, extends laterally away from the motor housing in the direction of the plane of the cutting disk, toward the workpiece. In the arrangement shown in the drawing, the axis of the handle 4, and the imaginary line connecting the center of the cutting disk with the front of the motor, constitute diverging straight lines extending from the front end of the motor shaft towards the surface of the board 6, or other piece which is to be cut. A triggerlike button 42 in the handle is arranged to suitably control the energization of the motor .11 through the switch 43, for instance, to have the motor running only as long as the button is depressed.

The motor housing 16 with the integral handle 4, as well as the combined tool-carrier and transmission housingZ, are each made of single castings, preferably of aluminum to reduce as much as possible the weight of the tool and avoid a 7' multiplicity of parts that are to be assembled and aligned.

The above-described tool unit comprising the motor with the forwardly projecting cutting disk and the downwardly extending grip 4 constitute a structure which is in itself well adapted to perform most of the cutting operations usually carried out by hand saws, the entire tool being relatively light, with the parts so balanced that by holding the grip 4 the cutting disk 3 will be easily guided in the direction in which the cut is to be made. This guidance is facilitated by the coplanar arrangement of the cutting disk and the grip.

The divergent support of the grip and the cut-- weights of the tool parts, supporting the tool principally on the work-piece, and the hand of the operator serving principally for directing the cutting blade.

The foregoing arrangement places the center of gravity of the tool unit at a point in the motor back of the place where the grip is joined thereto. Accordingly, when approaching the work the preponderant weight of the tool unit acts somewhat back of the handle, so that little eifort is required by the operator holding the grip to support the tool. The vertical line from the center of gravity will then intersect the line of the arm back of the handle.

On the other hand, when the cutting disk is tilted forwardly during the cutting operation, the center of gravity of the tool unit will come to lie so that the vertical line therefrom will intersect the line between the lower end of the grip and the cutting edge, thus relieving the operator from substantially all efforts in carrying the tool. In particular, by resting the lower side 43 of the transmission housing against the surface of the object to be cut, and also resting the lower end of the grip 4 on said surface, very extended cutting operations may be accurately carried out without strain on the operator.

In order to secure full balance of the forces involved in operating the tool, the motor drive of the cutting disk is so arranged that, when viewed in the direction toward Fig. 1, the disk 3 rotates in counter-clock-wise direction, causing the cutting teeth to underbite the object that is being cut, thus pulling the tool towards the object, the reactional forces from the cutting disk exercising a stabilization pressure on the handle 4.

While the foregoing tool as described above will perform all of the operations, usually carried out with hand saws, in a very eflicient way, its usefulness and field of application is greatly increased through the provision of the aforementioned base 5 which serves to, increase the accuracy with which the cutting disk may be'guided on the work-piece, eliminates substantially all strain on the operator while carrying out cutting operations, and permits close determination of the depth of the cut as well as the angle thereof with respect to the outer surface of the work-piece. The base is also arranged to act as a guard protecting the operator against accidental contact with the cutting blade when the tool is removed from the work-piece.

In the preferred construction shown in the drawings, the base 5has the shape of an elongated, relatively fiat tray, the bottom member of which constitutes a face plate 51 arranged to bear against the surface of the work 6, that is to be cut. The face plate 51 has a centrally disposed, longitudinal slot 52 through which the cutting edge of the saw may be projected toward the work-piece 6. The tool unit is suitably mounted on the base so as to permit the cutting disk 3 to be projected through the slot 52. In the preferred embodiment of my invention, this mounting comprises a double-pivotal, or gimbal, joint between the lower end of the grip 4 of the tool unit and the back end portion 53 of the base 5. The joint between the grip 4 and the base 5 comprises a cross-piece54 extending between the upstanding side wall portions 55 of the base 5, the cross-piece being pivoted at its ends to said side pieces by means of pins 56 to permit swinging movement of the cross-piece around said pins. Approximately in the center of the cross-piece 54, there is provided an upwardly projecting ear 5'7 which extends between two similarly shaped downwardly extending ear members 58 at the lower end of the grip 4 to provide by means of a suitable pin 59, preferably in the form of a screw threaded stud, a second pivotal connection around which the grip, with the motor unit and tool unit rigidly connected thereto, may be tilted sldewise in a direction transverse to .the direction of the cutting disk or blade 3.

The double pivotal connection of the handle to the base 5 thus permits a double swinging or tilting movement of the tool unit and the associated cutting disk with respect to the base 5. The first-mentioned pivotal connection, through the pivots 56, permits swinging or tilting movement of the tool and the blade in the direction of the cutting operation, thus making it possible to project more or less of the cutting blade through the slot 52 in the face plate 51, for regulating the depth of the cut. The second pivotal connection, through the pivot 59, permits swinging or tilting movement of the tool and cutting disk 3 in a direction transverse to the direction of the cutting operation for varying the angle under which the cutting disk 3 penetrates into the surface of, the object to be out While the first adjustment thus permits variations of the depth of the cut, the second adjustment permits the production of bevel or chamfered cuts and edges.

The foregoing arrangements for varying the depth as well as the angularity of the out are combined with provisions for pre-setting and determining the depth or the angularity before the cutting operation is begun, and with indicating means for readily showing the depth and angularity.

To this end I may provide, somewhat in front of the grip 4, on one side thereof, a depth gauge 61 comprising an upwardly projecting rod 62 which is joined at its lower end to an upwardly projecting ear 63 on the base 5. The connection between the base ear 63 and the lower end of the gauge rod 62 is in the nature of a universal joint permitting forward and sidewise tilting movement of the rod 62 corresponding to the tilting movements of the tool unit described above, as by means of a double pivotal connection composing pivots 64 and 65, shown clearly in Fig. 8 of the drawings. The upper end of the gauge rod is provided with a threaded perforation into which may be screwed an extension rod 66, the upper end of which has a head 67 adapted to act as a stop against which the lower side of the transmission housing 28 contacts to prevent a downward swinging movement of the tool unit beyond a point determined by the contact of said gauge head 67 with said transmission housing 28. The

thread on the extension rod 66 may be cut away on one side thereof and provided with a graduation for indicating the depth of the cut. The extension rod 66, when adjusted, may be fixed with respect to the swinging rod 62, as by means of a lock nut 68.

The tilting angle under which the cutting operation is carried on may also be readily predetermined by means of the pivot pin 59 at the bottom of the handle 4, the pin having its outer end screw threaded and provided with a lock nut and washer for locking the joint and fixing the angular position of the tool with respect to the base. A pointer '71 fixedly related to the base 5 cooperates with a suitable graduation 72 on the back of the handle, making it possible to read off the angle under which the cutting disk is tilted.

As far as I am aware the foregoing construction provides the first arrangement of a portable, motor-driven circular hand saw whereby bevel or chamfered cuts may be carried out with the same accuracy as was heretofore possible only with heavy, substantially immovable cutting machines. The high degree of accuracy of the cutting operation is greatly due to the arrangement of the base 5, the sides of which embrace the cutting disk throughout the full width of its cutting engagement with the work-piece. The forward, substantially-closed end of the face plate 51, which may be rested upon the work-piece in advance of the beginning of the cutting operation, also greatly aids the operator in making the correct approach to the work, and, to correctly start the cutting operation.

A distinct feature of my invention is the arrangement for projecting the base 5 away from the cutting tool, so that, when the tool is moved away from the work, the face plate 51 constitutes a guard that protects the operator, or other objects in the neighborhood, against accidental contact with the cutting disk 3. This arrangement may be secured, for instance, by the provision of a ring slidably surrounding the hinge rod 62 of the depth gauge 61, the ring being pivotally connected to the adjacent portion of the guard wall 23 of the tool housing as at 76. A compression spring 77 is provided around the lower portion of the hinge rod 62 and arranged to upwardly press against the ring 75, thereby tending to swing the base away from the cutting disk. This movement is limited by the abutment of the flanged upper end of the hinge rod 62 against the upper side of the ring 75.

In order to conveniently guide the tool, particularly for starting the cutting operation, it may be provided with an additional handle 78 that may be fixed by a threaded bolt screwed into a suitable threaded hole, either in the neck portion of the tool, at 79, or into the motor housing 16, at 80, or vertically on the guard rim of the tool housing, at 81, or at the side of the guard rim 24, at 82.

When making straight cuts on a fiat surface, as shown in Figs. 1 to 6, the tool is held with one hand on the grip and lifted above the work-piece, with'the front edge of the base resting on the edge of the piece to be cut. The spring 77, which holds the base projected away from the tool, is preferably so arranged that the weight of the tool when tilted forwardly around the pivots 56 will bring the cutting edge in contact with the surface of the work-piece, when the motor is put into rotation, the underbiting action of the cutting teeth will pull the cutting disk into the body of the work until the lower side of the transmission housing 28 will come in contact with the head 67 of the depth gauge and. thus stop further downward movement of the cutting edge. However, if necessary, a force exercised by the hand which guides the grip 4 will lift the cutting edge out of the groove, the weight of the motor being so balanced around the grip that the force necessary for lifting the saw will be relatively small.

When making angular cuts with a tool having the particular construction of the pivotal connection between the grip 4 and the base 5, shown in Figs. 1 to 11, it is necessary to make the proper adjustments with respect to the depth, as well as to the angularity of the cut in advance of the cutting operation. To this end the tool is first swung until a portion of the cutting disk 3, corresponding to the desired depth of the out is projecting through the longitudinal slot 52 in the face plate51, the disk being held at said depth by clamping the ring 75 surrounding the gauge rod 62, as by means of a wing screw 85. With the ring 75 so fixed on the gauge rod 62, there will be no further swinging movement of the base with respect to the tool around the pivots 56 in the direction of the cutting plane, but the tool is still free to be adjusted around the pivot 59 at the lower end of the grip 4 for fixing the angle under which the cutting disk is inclined towards the surface of the face plate 51. After the tool is tilted to the desired degree, as shown by pointer 71 on the scale 72 at the back of the grip 4, the tool is locked in this position and is ready to be applied for performing the desired cutting operation, as

shown in Fig. 9. The additional handle 78, may, if desired, be used in any of the foregoing operations either during the preliminary steps in making the approach to the work-piece or during the entire operation.

The utility of my improved tool is still further increased by combining therewith a gauge or guide for pre-fixing the angle under which the cutting disk moves forwardly in the work-piece. To this end the left hand side of the base 5, when viewed from the back of the tool, is provided with two upstanding ear posts 91, carrying a guide rod 92, which may be secured in suitable perforations in the ears by means of set screws 93. A slide member 94 is mounted on the guide rod 92 and has a suitable bracket 95, a straight-edge or rule member 96 projecting downwardly below the face plate 51 of the base. The straight-edge 96 is mounted in the bracket member 95 of the slide 94 by means of a bolt and nut attachment 97 permitting the straight edge to be locked in any desired angular direction with respect to the sliding movement of the slide 94 lengthwise of the base 5. The direction of adjustment of the straightedge 96 on the bracket 95 may be read off by means of a suitable indicator 98 and a co-operative graduation 99 on the bracket member.

When the tool is out of operation, the slide 94, with the straight edge 96 downwardly projecting therefrom, is pulled toward the front end of the base 5 through the action of a cable 101 operated by a suitable spring wheel 102, the cable passing over a pulley 103, to hold the slide 94 towards the front end of the guide rod 92.

If a straight out is desired the straght-edge 96 is adjusted in a direction perpendicular to the direction of the cut, and the forward end of the base 5, and the straight edge 96 downwardly projecting therefrom, are brought in contact with the front side of the work-piece, such as the board 6, until the straight edge 96 is in line therewith. The tool may then be pressed forwardly and the cutting operation carried out, the base sl ding forwardly, being guided by the slide 94 to secure the desired direction of the out. g

If a miter cut is desired, with the drection of the saw inclined towards the side of the board that is to be cut, the straight edge is locked under the desired angle with respect to the guide rod 92, and the base and the straight edge 96 at the forward end thereof are brought in contact with the front edge of the board to be worked on, as in the case described above. On forward movement of the tool, the cutting disk will now proceed in a direction inclined against the directhe adjustment of the straight edge 96, the entire tool with the base sliding forwardly in the slide 94 under the predetermined angle.

By adjusting the straight edge 96 for a miter cut, and locking the handle to give the cutting disk 3 an angle with respect to the faceplate 51, a double bevel cut may thus be easily carried out.

Figs. 10 and 11 show my improved tool while making a bevel cut in a direction straight to the side of a board, and under an angle thereto, respectively.

To further facilitate the handling of my improved tool, I also provide means for removing the waste particles produced by the action of the cutting tool on the board or other work-piece. To this end, a fan 101, is arranged to provide an air blast that may be utilized to remove said waste particles from near the cutting edge of the disk 3.

In the embodiment of my invention shown in Figs. 1 to 11, the'fan 101 is adapted to suck air through the motor towards the front end thereof, expelling the blast of air so created through perforations 102 disposed along the circumferenceof the housing and thereby cooling the motor. At one point of the perforated circumference, there is provided an exit 103 to which may be attached a flexible hose 104, the forward end of which terminates in a nozzle 105 held at the edge of the slot 52 in the base 5, so that an air blast through the nozzle will blow away the waste particles tending to accumulate in front of the cutting edge. By making the air pressure generated by the fan in the front end of the housing sufficiently large, a powerful air blast will be produced at the nozzle, and by mounting the nozzle in definite relation with respect to the face plate 51 the blast will always be directed in prefixed relation to the point where the cutting edge.

emerges from the surface of the body that is being cut.

In the modification of my invention shown in F." gs. 12 and 13, the double pivotal connection between the tool unit and the base 5 is so arranged as to permit swinging movement of the cutting disk 3, when making cuts in a direction perpendicular to the surface of the work-piece, as well as when making bevel cuts, with the plane of the cutting disk disposed at an angle to the surface of the work-piece. This result is secured by changing the order in which the two pivotal axes in the joint between the grip 4 in the base follow each other. Thus, in Figs. 12 and 13, the axis of the first pivotal connection 111 nearest to the base is arranged to provide tilting movement of the handle 4 and the tool in the direct on transverse to the cutting movement of the saw, thus permitting adjustment of the angle under which the cutting disk is inclined to the face plate 51, for varying the angle of the cut. The axis of the second pivotal connect on 112 is so arranged, thatjwith the first pivotal connection 111 locked, the tool may be freely swung in the direction of the cutting plane towards, and away from, the surface of the work-piece for varying the depth of the cut as well as for permitting withdrawal of the tool from the slot 52 in the face plate during the cutting operation, as in the caseof straight cutting operations with that form of the tool shown in Figs. 1 to 11.

- Furthermore, in order to secure correct indications of the depth of the cut with a single gauge, the depth gauge 61, which is similar to that of the modification shown in Figs. 1 to 11, is placed in the plane of the cutting disk, with the hinge connection of the gauge rod 62 so arranged as to cause the depth gauge to swing with the tool within the entire range of adjustments thereof,

The modified tool shown in Figs. 12 and 13 also provides for removal of the cutting waste from in front of the cutting edge through suction instead of through blow action, thus leaving the surroundings of the cutting tool free from v waste particles, and eliminating dust laden air from the neighborhood of the operator. To this end, the motor housing may have, between the suction fan 101 and the rotor 12 of the electric motor, a suct'on or vacuum chamber 115, the rotating fan 101 sucking air from the vacuum chamber 115 and expelling the same into a relatively porous bag 116 held on one side of the motor housing 16, the air escaping from the bag through the pores thereof. A hose 117, having one end terminating near the front edge of the cutting dsk, is so connected to the vacuum chamber 115 that the rotation of the fan 101 sucks through the hose 117 the produced waste particles, and expels the same into the bag 116 from where they may be removed.

It is'very often desirable to use a saw of the above described character for cutting longitudinal strips in a board, or the like, and to this end I may provide the base of the tool, such as shown in Figs. 1 to 11,'or Figs. 12 and 13, with a ripping gauge 121, a plan view of which is shown in Fig. 14. In the constructon shown in the drawings, the slide 94 has been removed from the guide rod 92 by releasing the set screws 93 and sliding the guide rod out from the ear posts 91. Instead of the slide 94, two guide members 122 may then be slid, or, if necessary, fixed, on the guide rod 92, and the rod with the guide members again secured in place in the ears 91. The guide members 122 have laterally projecting, slotted guides 123 to which may be secured clamp 115 bolts 124 which hold, at their lower end, a ripping gauge in the form of a straight rod that is parallel to the direction in which the cutting disk is to proceed. The guide members 122 are provided with graduation scales to per- 120 mit close determination of the width of the piece to be cut, and the clamping bolts 124 may then be suitably locked in position. The ripping gauge 121 will then project downwardly below the level of the piece to be cut, and bear thereagainst for 125 guiding the cutting disk through'the operation.

The two forms described above are intended as illustrations of the ways in which the many novel features characterizing my invention may be practically applied. As shown, my new tool has the weight and the masses of the various parts so distributed that the tool is balanced in the hand of the operator and relieves him from excessive stresses. The arrangement of the base for guiding the tool and for permitting close determination of the depth of the cut,-as well as of the angle thereof, is another outstanding feature of my invention. Associated with the foregoing functions of the tool is also an arrange- 'ment whereby the base may be projected away cutting surface. The tool is thus adapted for operation not only at right angle lines, as in the conventional cross-cutting of lumber, but also for miter and bevel cuts. The utilization of the ventilating means of the motor for removing the sawdust or waste from in frontof the cutting tool is another feature which greatly increases the utility of the tool. In the accompanying claims I desire to cover not only the individual elements for characterizing the various novel features present in my improved tool, but also the various combinations thereof which greatly contribute to its utility as well as to the universality of its applications.

I claim as my invention:

1. In a motor-driven hand tool, a motor, a circular cutting disk supported by said motor and rotated thereby for performing cutting operations, a base having a face adapted to engage the surface of the piece to be out, said base having a slot permitting said tool to be projected therethrough against said surface to. cut the same, a grip joining said motor and the associated tool to said base for guiding said tool and said base over the surface to be cut, and an adjustable connection on said grip for adjustably fixing the angle under which the cutting disk projects through said slot with respect to the face of said base.

2. In a motor-driven cutting tool, the combination with a power unit comprising a motor, a circular cutting disk supported at the front end of said motor and driven therefrom, and a handle laterally extending from said motor for supporting the same and said cutting disk by an operator, of a base unit having a pivotal connection with said handle for guiding and supporting said power unit during cutting operations, said base unit having a slot permitting said disk to be projected therethrough towards a work-piece when swung around-said pivotal connection, the masses of said power unit being so distributed with respect to said handle that when said base unit is swung away from said power unit a perpendicular line from the center of gravity of said power unit to the base will intersect the same at a point back of said handle, and when said cutting disk is swung toward said base to carry out cutting operations a perpendicular line from said center of gravity will intersect said base at a point in front of said handle.

3. In a motor-driven cutting tool, the combination with a power unit comprising a motor, a circular cutting disk supported at the front end of said motor and rotated thereby, and a handle laterally extending from the front end of said motor for gripping said tool by an operator, of a base unit having a face adapted to bear against a work-piece for supporting and guiding said powerunit during cutting operations, a pivotal connection between said handle and said base unit for joining the same to permit swinging movement of said base toward and away from said cutting disk, said base having a slot permitting said cutting disk to be swung therethrough toward said work-piece for cutting operations, means tending to yieldably swing said base away from the cutting disk, the masses of said power unit being so distributed with respect to said handle that the preponderant weight of said power unit acts back of said handle when power unit acts in front of said handle when the disk of the power unit is swung into said slot.

4. In a motor-driven cutting tool, the combination with a power unit comprising a motor, a circular cutting disk supported at the front end of said motor and rotated thereby, and a handle laterally extending from the front end of said motor for gripping said tool by an operator, of a base unit having a face adapted to bear against a work-piece for supporting and guiding said power unit during cutting operations, a pivotal connection joining said handle to said base unit to permit swinging movement of said base toward and away from said cutting disk, said base unit having a slot to project said cutting disk therethrough toward a work-piece for cutting operations, means tending to yieldably swing said base away from the cutting disk, the masses of said power unit being so distributed with respect to said handle that a perpendicular line from the center of gravity of said power unit to the face of said base unit intersects said face substantially back of said handle when said base is swung away from the disk, and intersects said face in front of said handle when said cutting disk is swung toward said slot to perform cutting operations.

5. In a cutting tool, a motor housing, a rotary motor mounted in said housing, a cut-ting disk extending in front of one end of said motor housing and supported therefrom, a handle extending on one side of said housing in the plane of said cutting disk for guiding and supporting the same, said disk being rotated by said motor, a base having a face adapted to bear against the surface of a work-piece, said base having a slot for exposing a portion of the cutting diskcorresponding to the depth of the out toward the work-piece,

a pivotal connection joining said handle to said base for varying the angle between the plane of the cutting disk and the face of the base to vary the direction under which the cutting disk penetrates into the piece to be out.

6. In a cutting tool, a tubular motor housing, a rotary motor mounted in said housing, a cutting disk extending in front of one end of said motor housing and supported therefrom, a handle extending on one side of said housing for guiding and supporting the same, said disk being rotated by said motor, and a base having a face adapted to bear against the surface of a work-piece, said base having an opening for exposing a portion of the cutting disk corresponding to the depth of the out toward the work-piece, a pivotal connection joining said handle to said base for varying the angle between the plane of the cutting disk and the face of the base, means for locking said pivotal connection to secure a predetermined cutting angle with respect to the face, and additional pivotal connecting means interposed in the connection between said handle and said base to permit swinging movement of said cutting disk toward and away from the work-piece during the cutting operation without affecting the angle of the cut.

7. In a motor-driven hand tool, a rotary motor having a casing enclosing the same, a tool housing rigidly supported at one end of said motor housing in the direction of the axis of rotation thereof, a circular cutting disk rotatably mounted in said tool housing, in a direction substantially parallel to the motor axis, power transmitting means interconnecting said motor and said cutting disk to rotate the latter for performing cutting operations, said tool housing having a compartment completely enclosing said power transmitting means, a handle rigidly extending from said motor housing for guiding the motor and the cutting disk during the cutting operations, said handle and said cutting disk being disposed in a median plane of said motor, a base having a face plate for supporting said cutting disk on the surface of the body to be cut, said face plate having a slot for exposing said cutting disk towards said surface, a pivotal connection between said handle and said base plate permitting said disk to be swung through said slot toward and away from said base plate to vary the exposed depth thereof, resilient means tending to swing said base away from said disk for interposing said face plate as a guard in front of the cutting edge of said disk when removed from the work-piece,'and adjustable gauge means for fix-- ing the depth of the cut comprising an adjustable stop limiting the extent to which the disk may be swung towards said face plate, and a portion thereof exposed through said slot.

8. In a motor-driven hand tool, a base having a face plate adapted to bear on the surface of an object to be cut, a cutting tool comprising a motor and a circular cutting disk supported by said motor and rotated thereby, said base having an opening through which said disk may be projected to perform the cutting operation, means for so supporting said tool from said base as to secure a predetermined relationship between the plane of the cut and the plane of the face plate,

. a guide adapted to fixedly bear against the object to be cut, said base being held in sliding engagement with said guide to permit relative movement therebetween, and means for fixing the relative direction of said movement to determine the direction of the cutting operation on said object, said guide being longitudinally movable along said base in the direction of the cutting operation, and means for automatically bringing said guide to the point on said base where it is located when starting a cutting operation.

9. In a motor-driven hand tool, a base having a face plate adapted to bear on the surface of an object to be cut, a cutting tool comprising a motor and a circular cutting disk supported by said motor and rotated thereby, said base plate having a longitudinal slot extending parallel to the direction in which the tool is to cut, means for so supporting said motor and the associated cutting disk from said base as to cause a portion of the said disk to project through said slot to expose therethrough a portion of the disk corresponding to the depth of the cut, 'a cutting guide comprising a guide member adapted to be fixedly held against the object to be cut for determining the direction of the cutting operation, a gliding connection between said member and said base to permit said guide member to move longitudinally along said base parallel to the direction. of said slot along said base, resilient means tending to normally hold said guide at the front end of said base, said guide being so arranged that said base glides forwardly on said guide member while proceeding in the cutting operation.

10. In a motor-driven hand tool, a base having a face plate adapted to bear on the surface ofan object to be cut, a cutting tool comprising a motor and a circular cutting disk supported by said motor and rotated thereby, said base plate having a longitudinal slot extending parallel to the direction in which the tool is to cut, means for so supporting said motor and the associated cutting disk from said base as to cause said disk to project through said slot exposing'therethrough a portion of the disk corresponding to the depth of the cut, a cutting guide slidably mounted on said base to permit longitudinal movement thereof parallel to the direction of the slot, said guide comprising a substantially straight-edge member projecting below the plane of said face plate and adapted to bear against a side of an object to be cut, and means for so adjustably fixing the direction of said straight-edge member with respect to the sliding movement thereof in said base as to secure predetermined angular movement of the cutting plane with respect to said side of the object to be cut.

11. In a motor-driven hand saw, an electric driving motor, a tubular housing enclosing said motor, a handle downwardly extending from said housing near the front end of said motor, a unitary tool housing supported in front of the end of said motor housing near said handle, acircular saw disk rotatably supported in said tool housing to rotate in a medial plane through said motor and said handle, power transmitting means interconnecting said motor and said disk to rotate the latter, said unitary housing comprising a substantially semi-circular guard extending over the upper part of the cutting edge of said'disk on the side substantially opposite to the line interconnecting the end of the handle and the center of the disk, bearing means in a side wall of said guard for journaling said cutting disk, said power transmitting means being disposed on the other side of said guard wall, and a transmission housing enclosing said power transmitting means, the

lower surfaces of said unitary tool housing and said handle constituting a substantially co-planar supporting base and guide for said tool unit.

, 12. In a motor-driven hand tool, a power unit including a motor and a cutting disk supported and driven by said motor, a base adapted to bear against and slide on the work during the cutting operation, a supporting connection between sai base and said power unit, a guide slidably arranged on said base adapted to be held fixed with respect to said work during the cutting operation, and means for normally returning said guide to a predetermined position on said base.

13. In a hand-portable motor-driven saw, a power unit comprising a motor and a saw disk supported at one end of said motor and driven thereby, the plane of said disk extending longitudinally in front of said motor, a base plate underlying said power unit and arranged so that the longitudinal extension thereof is intersected by the line of gravity of said power unit, and a pivotal connection between said power unit and said base plate for pivoting said power unit about an axis lying in the plane of said disk to bring said disk under adjustable inclination to the surface to be out, said pivotal connection being arranged to permit swinging movement of said disk into the work in inclined position.

14. In a motor-driven cutting tool, a power unit ISO comprising a motor, a circular cutting disk exg tending along a medial plane through said motor and supported by said motor and driven therefrom, a base underlying said power unit and directly bearing against the surface to be cut for guiding said motor and the associated cutting disk, and a connection between said power unit and said base for pivoting said power unit about an axis lying in the plane of said disk to bring said disk'under adjustable inclination to the surface to be cut, and permitting variation of the depth of the out while carrying out the cutting operation.

it. In a hand-portable motor-driven saw, a power unit comprising a motor, a circular saw disk substantially vertically supported on the front end of said motor and driven thereby, said saw disk extending longitudinally in front of said motor, a guard enclosing the upper edge of said saw and exposing for cutting action only the downward edge of the saw, and a depending han= dle downwardly extending from the under-side of said motor at its forward end and backward thereunder so that the weight of said motor is above said handle.

16. In a hand-portable motor-driven saw, a power unit comprising a motor, a circular saw disk substantially vertically supported on the front end of said motor and driven thereby, said disk extending longitudinally in front of said motor, a guard enclosing the upper edge of said saw and exposing for cutting action only the downward edge of the saw, and a depending handle downwardly extending from the under-side of said motor near the end on which said saw disk is supported.

1'7. In a portable saw, a tubular motor housing, a rotary motor axially mounted in said housing, a saw disk longitudinally extending in substantially vertical direction in front of one end of said motor housing and supported from said housing, a handle extending from the front end of said housing downwardly away therefrom for guiding and supporting said saw, and a guard enclosing the upper edge of said saw and exposing for action only the downward edge of the saw, the masses of the several members of said saw being so distributed that the preponderant weight thereof acts back of the handle, when the same is gripped by an operator to hold the saw in approaching the work. I

18. In a motor-driven cutting tool, a motor, a handle downwardly extending from the front end of said motor and having its lower'end adapted to engage the work, and a saw disk supported on the end of said motor in front of said handle in a substantially vertical plane, said saw disk being rotated by said motor in a direction in which the reactive forces exercised on said tool during the cutting operation tend to press said handle against the work that is being cut to act as a support for said tool.

19. In a hand-portable motor-driven saw, a power unit comprising a motor, a circular saw disk substantially vertically supported on the front end of said motor and driven thereby, said saw disk extending longitudinally in front of said motor, a guard enclosing the upper edge of said saw and exposing for cutting action only the downward edge of the saw, and a depending handle downwardly extending from the under-side of said motor so that the weight of said motor is above said handle, said handle lying in substantially the same plane as said saw disk.

. through said slot.

wagon 20. In: a hand-portable motor-driven saw, a power unit comprising a motor, a circular saw disk substantially vertically supported on the front end of said motor and driven thereby, said disk extending longitudinally in front of said motor and having a relatively large diameter so that its lower edge projects downwardly for a substantial distance beyond the lower edge of said motor, a guard enclosing the upper edge of said saw and exposing for cutting action only the downward edge of the saw, and a depending handle downwardly extending from the underside of said motor near the end on which said saw disk is supported.

21. In a hand-portable motor-driven saw, a power unit comprising a motor and a circular saw disk supported longitudinally in front of one end of said motor and driven thereby, a base plate for guiding and supporting said saw having a supporting face suficient to support said saw in stable equilibrium throughout the normal range of operation thereof, the lower edge of said disk being directed against said base, and a depending handle having its upper end connected to the under-- side of said motor near the end on which said 1 cutting disk is supported, and its lower end movably connectedto said base plate.

22. In a hand-portable motor-driven tool, a power unit comprising a motor and a circular saw disk supported longitudinally at the front end 1 of said motor and driven thereby, a depending handle having its upper end connected to the under-side of said motor near the front end thereof, a base plate movably joined to the lower end of said handle and arranged to always intersect the transverse plane of the center of gravity of said power unit and stably support the same, said base plate having a slot for projecting therethrough the cutting edge of said disk for performing cutting rperations, and means for q yieldably holding said base plate in front of said cutting edge to act as a guard therefor.

23. In a hand-portable motor-driven tool, a power unit comprising a motor and a circular saw disk supported longitudinally at the front end of said motor and driven thereby, a depending handle having its upper end connected to the under-side of said motor near the front end thereof, a base plate movably joined to the lower end of said handle and arranged to always intersect the, transverse plane of the center of gravity of said power unit and stably support the same, said base plate having a slot for projecting therethrough the cutting edge of said disk for performing cutting operations, means for yieldably holding said base plate in front of said cutting edge to act as a guard therefor, and an adjustable stop for determinedly limiting the extent to which the disk may be swung towards said base plate, and aportion thereof projected towards the work 1 ALEX A. CKE.