US2843917A

US2843917A - Band sawing machine

Info

Publication number: US2843917A
Application number: US630171A
Authority: US
Inventors: Robert L Crane; James W Wilkie
Original assignee: Continental Machines Inc
Current assignee: Continental Machines Inc
Priority date: 1956-12-24
Filing date: 1956-12-24
Publication date: 1958-07-22
Anticipated expiration: 1975-07-22

Description

July 22, 1958 R. CRANE ET AL BAND SAWING MACHINE 8 Sheets-Sheet 1 Filed Dec. 24, 1956 July 22, 1958 R. L. CRANE ET AL 2,343,917

BAND SAWING MACHINE Filed Dec. 24, 1956 8 Sheets-Sheet 2 170174 2? I. [mm Jim W Wz/km July 22, 1958 R. L. CRANE ET AL BAND SAWING MACHINE 8 Sheets-Sheet 3 Filed Dec. 24, 1956 10274 2 2! [may E Jamgs W Wz/lrm July 22, 1958 R. L. CRANE ET AL 2,843,917

BAND SAWING MACHINE 8 Sheets-Sheet 5 Filed Dec. 24, 1956 July 22, 1958 R. CRANE ET AL 2,843,917

BAND SAWING MACHINE Filed Dec. 24, 1956 1 8 Sheets-Sheet 6 July 22, 1958 R. L. CRANE ET AL BAND SAWING MACHINE 8 Sheets-Sheet '7 Filed Dec. 24. 1956 Zaharzl. [MM Jizzzgs W Ml/tw July 22, 1958 R. CRANE ET AL 2,843,917

BAND SAWING MACHINE Filed Dec. 24, 1956 s Sheets-Sheet 8 1 017:?! J. mm: Jam: 1 Iii/Av! United States Patent nnnn sawrno MACHINE Robert L. Crane and lames W. Wilkie, Hopkins, Minn, assignors to Continental Machines, Ina, Savage, Mrnn., a corporation of Minnesota Application December 24, 1956, Serial No. 630,171

14' Claims. (El. li -6 This invention relates to improvements in machine tools on the order of that disclosed in the copending application of Robert L. Crane, Serial No. 488,536 filed February 16, 1955, wherein work is performed on large and heavy work pieces while the latter are held stationary and the machine is moved bodily relative thereto so as to feed its work performing element into the work piece' The machine tool of said application is a filing machine especially adapted for use in filing dies and other work pieces that are too large and. heavy to be moved about in order to present selected areas thereof to the file element. In general, it comprises a C-shaped carrier which is mounted over a horizontal supporting surface for substantially free movement in all directions parallel to said surface, and it is provided with a vertically reciprocable file element mounted in suitable rotary guide members on the arms of the C-shaped carrier with the file element spanning the working space between the carrier arms. The file element is freely slidably but nonrotatably received in the guide members and the latter are constrained to rotate in unison and in the same direction so that the operator of the machine may turn the file element in its path of travel to present its abrading surface to different areas of the work piece merely by imparting rotation to the guide members. The operator also manually moves the C-shaped carrier bodily to effect feeding of the file element into the work piece, and a single handle member readily accessible to the operator is connected to one of the rotary guide members to facilitate both guiding and feeding of the file element into the work.

Despite the fact that the C-shaped carrier was supported from a stationary pedestal by means of a free swinging double hinge mounting to enable it to be moved in all directions parallel to the supporting surface with a minimum of effort, it nevertheless required a skilled operator to coordinate two motions, namely, swinging of the carrier bodily along with turning of the tool element relative to the carrier, while also controlling his application of tool feeding force to the carrier in order to achieve efficient and accurate machining. Thus for example it was quite difiicult for all except the more highly skilled and experienced operators to utilize the machine of the aforesaid copending application to its best advantage, especially if there was any tendency on the part of an operator maintaining accuracy foremost in his mind to ease up or even momentarily forget to move or swing the carrier in the direction in which he had turned the file element, and to apply to the carrier the force necessary for efficient filing.

It is the primary purpose of this invention, therefore, to provide a machine tool of the character described having power operated means for imparting swinging and tool feeding motion to the carrier, and wherein such swinging motion of the carrier is automatically coordinated with manual turning of the tool element relative to the carrier.

Another purpose of this invention resides in the provision of power operated means of the character described ICQ 2,843,917 Patented July 22, 1958 which is applicable to the C-shaped carriers of sawing as well as filing machines of the type described.

More specifically it is an object of this invention to provide a machine tool such as a sawing or filing machine with a guide wheel driven by a torque motor and mounted on the bottom of the G-shaped carrier of the machine for tractive engagement with the supporting surface over which the carrier moves and constrained to swiveling motion about the common vertical axis of the rotary tool guiding members, in unison with rotation of said tool guiding members, upon turning of the latter by the operator.

In the case of the band sawing machine herein disclosed, it will be understood that the tool. element is an endless saw band trained about suitable drive and idler pulleys on the C-shaped carrier with one stretch thereof constrained to continuous travel downwardly along a vertical path through the working space between the arms of the carrier by means of spaced upper and lower tool guiding members similar to those employed in the filing machine of the aforesaid copending application. These tool guiding members are also mounted on the carrier arms for rotation in unison in opposite directions about a common vertical axis coincident with the cutting edge of that stretch of the saw band which extends between the guide members, and the saw band, of course, is freely slidably but nonrotatably received in the guide members so that rotation imparted manually thereto effects turning of the band by twisting that stretch thereof which extends between the guide members.

Still another object of this invention resides in the provision of a machine tool of the character described with means for readily releasably maintaining the power driven guide or feed Wheel in tractive engagement with the supporting surface over which the tool carrier is driven by the wheel.

In this respect it is a more specific object of the invention to mount the guide or feed wheel on the tool carrier of a machine tool of the character described by means of a spindle which provides for swiveling motion of the wheel about a vertical 'aXis common to that about which the tool guiding members rotate, and which spindle comprises the plunger of a double acting fluid pressure operated cylinder so that pressure exerted in one end of the cylinder causes the guide or feed wheel to be maintained in tractive engagement with the supporting surface while pressure exerted in the other end of the cylinder effects retraction of the wheel away from the supporting surface to permit the carrier to be quickly moved manually.

Still another object of this invention resides in the provision of a machine tool of the character described wherein the power driven guide wheel may be automatically turned about its vertical axis to change the direction of tool feeding motion of the tool carrier by a motor at the dictation of tracer means which follows an edge portion on a template having the outline of the desired cut to be made in the work piece.

With the above and other objects .in view, which will appear as the description proceeds, this invention resides in the novel construction, combination and arrangement of parts substantially as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate several complete examples of the physical embodiments of the invention constructed according to the best modes so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a side elevational view of a band sawing machine embodying the principles of this invention, portions thereof being broken away to illustrate details of construction;

Figure 2 is a plan view of the machine shown in Figure 1;

Figure 3 is a more or less diagrammatic perspective view showing the manner in which the power operated guide wheel is constrained to turn with the saw band guides;

Figure 4 is an enlargement of the band guiding and power feeding mechanism seen in Figure 1;

Figure 5 is a vertical sectional view through the lower band guiding member, taken along the plane of the line 5-5 in Figure 4;

Figure 6 is a vertical sectional view through the upper band guiding member, taken along the plane of the line 66 in Figure 4;

Figure 7 is a vertical sectional view through the guide wheel mechanism and the means which mounts the same, taken along the plane of the line 7-7 in Figure 4;

Figure 8 is a vertical sectional view taken through Figure 7 along the plane of the line 8-8;

Figure 9 is a diagrammatic perspective view illustrating the control means for starting and stopping the torque motor for the guide wheel;

Figure 10 is a perspective view similar to Figure 3 but illustrating a modified embodiment of the invention wherein the guide wheel is constrained to follow a template.

Figure 11 is a detail sectional view showing the manner in which the guide wheel is engaged with the template shown in Figure 10;

Figure 12 is a perspective view similar to Figure 3 but illustrating another manner in which a template may be used to control the direction of feeding motion of the tool carrier;

Figure 13 is a diagrammatic view of a portion of the template following mechanism shown in Figure 12, and illustrating how a hydraulic motor for turning the guide wheel on its vertical axis may be governed thereby; and

Figure 14 is a fragmentary perspective view showing another embodiment of the invention.

Referring now particularly to the accompanying drawings in which like reference characters have been applied to like parts throughout the several views, the machine tool of this invention is shown as comprising a band saw, although it will be understood that the invention is equally well applicable to filing machines of the type disclosed in the copending application of Robert L. Crane, Serial No. 488,536, filed February 16, 1955. The main components of the band saw are substantially identical to those of the filing machine of the aforesaid copending application, and comprise a fixed pedestal A; an arm B hingedly connected to and supported from the pedestal for free swinging motion in opposite directions about a vertical axis; a C-shaped rigid frame or carrier C hinged to and supported from the outer end of the arm B for swinging motion in opposite directions about a vertical axis; a tool element D, which in this case is an endless saw band; and a power operated guide or feed wheel E.

The pedestal A, of course, is suitably anchored to a base or foundation having a horizontal supporting surface S, and the axes of the double hinged connection between the carrier C and the pedestal are exactly vertical. By reason of this double hinged connection, therefore, the carrier C may be swung in all directions relative to the pedestal, parallel with the horizontal supporting surface S, and the wide area in which work may be performed by its tool element D upon a Work piece W held in a stationary position by any suitable means, is diagrammatically illustrated in Figure 2.

As is more or less conventional in sawing machines having a continuous saw band, the tool element or endless saw band D is trained over pairs of vertically aligned inner and outer band wheels or pulleys P on the carrier so arranged that the cutting stretch of the band, which extends between the outermost pair of pulleys, travels downwardly in a vertical path through the working zone defined by the space between the horizontal upper and

lower arms

10 and 11, respectively, of the C-shaped carrier. One of the pulleys P, preferably that which is carried by the outer end portion of the lower arm 11 of the C-shaped carrier, is connected with a motor 12, and the other pulleys are idlers, but one of these idler pulleys is journalled in a slidably mounted block for band tensioning adjustment by any suitable means such as the hand screw shown in Figure 1 or the hydraulic cylinder shown in Patent No. 2,607,373, which points out that the tension maintained on the band must be correlated to the width of the band.

The cutting stretch of the saw band is constrained to linear vertical travel through the working zone by means of vertically spaced upper and

lower guide members

14 and 15 respectively mounted on the upper and lower arms of the carrier.

Each of these guide members comprises a bearing housing 16 having a tube 17 constrained to rotation on a vertical axis therein, and a sleeve 18 within and projecting entirely through the tube with the sleeve splined thereto as at 19. The bearing housings are so mounted on the outer ends of the upper and lower carrier arms as to hold the tubes and their sleeves on a common vertical axis which lies in the plane of the cutting stretch of the saw band, and in most instances is coincident with the toothed edge 20 thereof.

The cutting stretch of the saw band, of course, extends downwardly through the sleeves of both the upper and lower guide members to be slidably but nonrotatably received between the jaws of saw guides 21 carried by collars 22 fixed to the adjacent ends of the upper and lower sleeves 18. While the sleeves are constrained to rotate with the tubes 17, their splined connections with the tubes permit them to be adjusted vertically, relative to the carrier arms, and they may be held in any desired position of vertical adjustment by means of annular clamping members 23 on the tubes through which the adjacent end portions of the sleeves project. A screw 24 on each of the clamping members, when loosened, provides for such up and down adjustment of the sleeves with respect to their tubes 17, but the sleeves are held against all but rotary motion with their tubes when the screws are tightened.

As in the aforesaid copending application the tubular members of the upper and lower guides are constrained to turn in unison, and for this purpose they are drivingly connected together. This driving connection comprises a vertical shaft 25 rotatably mounted in a vertical position in the bak of the C-shaped carrier, and chain and sprocket connections 27 between the tubes 17 and the shaft. Manually operable handle means 28 mounted upon the clamp 23 of the upper guide member provides for the transmission of rotation to the upper and lower guide members to thus effect twisting of the cutting stretch of the saw band which extends between the guides 21, relative to the carrier, so as to enable turning of the band as required when following an irregular reference line delineated on a Work piece W held in a stationary position between the arms of the carrier. The handle means 28, of course, also enables the operator to move the entire carrier C on its double hinged support when feeding motion of the saw band into the work is to be imparted to the carrier manually. While the handle means has been illustrated as comprising a pair of diametrically opposite arms having grips 29 on their outer ends, it will be appreciated that a ring or wheel 29 may be substituted for the grips as shown in Figure 14.

According to this invention, tool feeding motion is d imparted to the carrier by means of a power driven feed or guide wheel 30 carried by the lower arm 11 of the carrier and having its periphery in tractive engagement with the supporting surface S over which the carrier moves.

The guide or feed wheel is fixed on a horizontal axle 31, the ends of which are journaled in suitable hearings on a wheel supporting member 32 having an electric torque motor 33 mounted on one side thereof. The motor is drivingly connected with the axle by means which includes a transmission 34 and gears 35 on the output shaft of the transmission and on one end of the axle.

The wheel supporting member 32 is mounted upon the lower end portion of a vertical spindle 37, with the wheel supporting member constrained to rotation about the axis of the spindle but prevented from axial motion relative thereto. As seen best in Figure 7, the spindle is hollow and comprises the plunger of a double acting fluid pressure operated cylinder 39 secured in the lower arm 11 of the carrier with the plunger or spindle coaxial with the upper and lower guide members for the saw band.

Mounted on the plunger or spindle 37 inside the cylinder 39 is a piston l-ti, so that when fluid under pressure is admitted into the cylinder at one side or the other of the piston the plunger or spindle 37 will be raised or lowered to carry with it the wheel supporting member 32 and the feed or guide Wheel 30 thereon. Thus, if fluid under pressure is admitted into the upper end portion of the cylinder to the space above the piston 40, as through a fluid line 41, the piston will be forced downwardly to tractively engage the periphery of the feed or guide wheel with the supporting surface S. In the event it is desired to lift the feed or guide wheel off of the supporting surface to facilitate manual swinging of the carrier from one location to another, fluid under pressure is introduced through a second fluid line 42 into the lower end portion of the cylinder to the space below the piston 40 to cause the wheel to be carried upwardly away from the supporting surface. Normally, however, fluid pressure is maintained in the upper end portion of the cylinder so as to assure good tractive engagement between the periphery of the feed or guide wheel 30 and the supporting surface.

An important feature of the invention resides in the fact that the wheel supporting member is constrained to rotate in unison with the guide members for the cutting stretch of the saw band. For this purpose the wheel supporting member 32 has a sprocket 44 fixed thereto opposite a sprocket 45 on the lower end of the vertical shaft 25, and a chain 46 is trained over the

sprockets

44 and 45.

It is important to note, however, that the horizontal axis about which the feed or guide wheel rotates is intersected by the common axis of the guide members and the spindle 3'7, and since this axis lies in the plane of the cutting stretch of the saw band and may, for instance, be coincident with the cutting edge of the saw band, it will be apparent that whenever the guide members are rotated manually to cause the saw to follow an irregular out in a work piece, the cutting stretch of the saw band will be twisted in its vertical path simultaneously with turning of the feed or guide wheel 30 on its spindle 37, in the same direction that the band is twisted. The motor 33 for the feed or guide wheel, of course, will impart rotation to the wheel in the direction to effect the necessary tool feeding force and motion of the G-shaped carrier.

With this arrangement, an operator of the sawing machine need only concentrate on turning or twisting the cutting stretch of the saw band in its vertical path, relative to the carrier C, during the cutting of an irregular course through a Work piece W, and that as a consequence of manual rotation of the guide members to twist the band, the power driven feed or guide wheel will be turned about its vertical axis in the same direction as the saw band and will impart tool feeding motion to the carrier d 7 along a path which is parallel to the opposite faces of the cutting stretch of the band. Moreover, inasmuch as the prime mover for the feed or guide wheel is a torque motor, it will be appreciated that it will tend at all times to maintain the cutting edge of the saw engaged with the work piece with a force which is constant and independent of the speed of feed motion.

Attention is directed to the fact that since the spindle or plunger 37 upon which the feed or guide wheel swivels is hollow, it enables the electrical conductor 48 by which energizing current is supplied to the motor 33 to be led downwardly therethrough and into the wheel supporting member 32, with the conductor located on the vertical axis about which the wheel swivels. The conductor 48 is preferably in the form of an elongated closely coiled helix extending coaxially through the interior of the spindle so that the feed or guide wheel and the wheel supporting member 32 upon which it is mounted may turn freely relative to the spindle 37 without any danger of damaging the electrical conductor.

Also as seen best in Figure 8, the helically coiled conductor 48 surrounds a tube 50 having its upper end projecting from the spindle or plunger of the fluid pressure operated cylinder and provided with an elbow fitting 51 by which it is connectible with a source of air under pressure. A nozzle 52 on the lower end of the tube, extending downwardly and forwardly ahead of the periphery of the guide wheel, enables a blast of air to be directed against the supporting surface S so as to blow aside chips of metal or other particles from the supporting surface before the guide wheel travels thereover.

Electrical control instrumentalities, generally desig nated 53 in Figures 1 and 14, govern the speed and operativeness of the torque motor 33. These instrumentalities are mounted on a control panel fixed to the outer end of the upper arm 10 where their actuators are readily accessible to an operator of the saw, and these instrumentalities include an on-olf switch, and a variable resistor by which the voltage to the torque motor may be regulated.

From the description thus far, it will be apparent that the feed or guide wheel 30 will be bodily moved toward tractive engagement with the supporting surface whenever the fluid line 41 leading to the upper end of the cylinder 39 is communicated with a source of fluid under pressure and the fluid in the lower end of the cylinder is free to exhaust through the fluid line 42; and that the wheel will be bodily moved to an inoperative position spaced from the supporting surface whenever the fluid line 42 is communicated with the source of fluid under pressure and the fluid in the upper end of the cylinder is free to exhaust through the fluid line 41. Suitable instrumentalities govern the connection of the

fluid lines

41 and 42 with the source, of fluid under pressure, and in the present case these instrumentalities comprise a solenoid. actuated valve, not'shown, and a double throw switch 54 which controls the valve. This switch is preferably mounted in the upper arm 10 of the carrier alongside the bearing housing of the upper saw guide member 14, and is actuated by a lever 56 pivotally mounted on one of the grips 29 of the handle means 28 so as to be readily actuatable by an operator.

The lever 56 is connected with the actuating arm 55 of the switch through a suitable motion transmitting connection including a Bowden wire 58, a ring 60 overlying and pivotally connected as at 61 to the top of the handlemember 28, and a pin 63; the Bowden wire being con nected to the ring and the lever. Therefore, when the operator actuates the lever in one direction the ring 60 is tilted upwardly on its hinge 61, and such tilting motion of the ring is translated into switch actuating motion of the switch arm 55 by means of the pin 63. Actuation of the switch in this manner efifects connection of the lower end of the cylinder 39 with the source of fluid under pressure to cause the feed or guide wheel 30 to be lifted ofi of the supporting surface to thus enable the operator to swing the C-shaped carrier freely in any direction. When the operator moves the control lever 56 in the opposite direction, the switch 54 returns to its normal position elfecting connection of the upper end of the cylinder 39 with the source of fluid under pressure, and causing the feed or guide wheel to resume its normal position tractively engaging the supporting surface.-

Obviously, if desired, the control valve (not shown) may be operated directly by the pin 63 or in any other manner as a consequence of swinging the control lever 56, in which event the switch 54 would not be needed.

With the apparatus described it will be apparent that a sawing operation carried out in a work piece W along an irregular layout line requires the presence of an operator to guide the cutting stretch of the saw band through the work, by turning the handle means to twist the cutting stretch of the saw band as required. The operator, however, need not be concerned with the bodily swinging motion of the carrier in correspondence with such twisting of the saw hand, nor need the operator give any attention to the maintenance of the required feed pressure between the cutting edge of the saw and the work. These two functions are carried out automatically by the "feed or guide wheel and its torque rnotor.

If desired, a template 66 having the shape of the cut to be made in the work piece may be employed in the manner shown in Figure to guide the wheel and thereby effect turning of the cutting stretch of the saw band in its vertical path as required to produce the desired cut in the work piece entirely aiutornatically. As shown in Figure 10 the template 66 may be secured to the supporting surface S beneath the lower arm 11 of the carrier and it preferably has a groove 67 in its upper surface to provide a track in which the peripheral portion of the feed or guide wheel 30 travels.

Depending upon the shape of the track, therefore, the Wheel 30 will be turned about its vertical axis as it travels along the track, and all of the swiveling motion which is thus imparted to the feed or guide wheel will likewise be transmitted to the saw guides 21 to effect twisting of the cutting stretch of the saw in the same direction that the feed or guide wheel swivels.

When an irregular cutout is to be made in the body of the work piece, however, it will be appreciated that a small hole 69 is first drilled inside the layout line delineated on the upper surface of the work piece to enable a proper length of saw band to be passed therethrough. The ends of the saw are then welded together to form a continuous band around the pulleys P, and the operator must manually direct the cutting operation to start the cut along the layout line. Thereafter, the guide wheel may be engaged with the template 66 to cause the remainder of the sawing operation to be carried out automatically.

Automatic operation of the sawing machine can also be effected in the manner disclosed in Figures 12 and 13 wherein swiveling motion is imparted to the guide wheel 30 about its vertical axis as a consequence of the engagement of a tiltable tracer finger 71 with the edge 72 of a template 73 mounted above the upper arm 10 of the carrier. In this case the tilting of the tracer finger effects sliding motion of the plunger 74 of a hydraulic control valve 75 which governs the flow of fluid under pressure to a reversible hydraulic motor 76. This hydraulic motor 76 has a drive sprocket 77 thereon connected by means of a chain 78 with a sprocket 79 on the upper end of the vertical shaft 25' so as to drivingly connect the hydraulic motor with the band guide members and the guide wheel 30.

As diagrammatically shown in Figure 13, the plunger 7 4 is biased upwardly toward engagement with the lower end'of the tracer finger, and it controls communication between an inlet port in the valve body connecting with a supply line 81, and a pair of motor ports in the valve body connecting with motor lines 82 and 83. Thus, with the tracer finger in a tilted position as shown, the plunger is held thereby in a position blocking both motor ports and the guide wheel 30 will feed the machine along a straight line path until the tilt angle of the tracer finger is changed by the template.

Thus, for example, if the template acts on the tracer finger to tilt it farther out of a vertical position, the finger slides the plunger downwardly to connect the motor line 32 with the supply line 81 for operation of the hydraulic motor in one direction. Fluid exhausting from the motor is returned to the valve through the other motor line 83 and flows to a sump through one of two return lines 84. The hydraulic motor, of course, is driven in said one di rection at a speed depending upon the rate at which fluid is allowed to pass into the line 82 by the plunger, and such operation of the motor effects swiveling of the guide Wheel in unison with twisting of the cutting stretch of the saw band in the proper direction as determined by the template.

The guide wheel and the saw band are turned in unison in the opposite direction by the hydraulic motor in the event the template causes the tracer finger to assume a position of less tilt than is shown in Figure 13. In that case, the valve plunger connects the motor line 83 with the supply line, and the motor line 82 with the other return line 84, to reverse the hydraulic motor.

From the foregoing description taken together with the accompanying drawings it will be readily apparent to those skilled in the art that this invention materially improves the operation of machine tools such as sawing and filing machines in that it minimizes the amount of attention which an operator must give to the machine in order to perform work, such as cutting or abrading, along a predetermined reference line on a Work piece.

What is claimed as our invention is:

l. A machine tool of the type comprising a (t-shaped carrier having spaced apart upper and lower arms defining a working zone therebetween, means mounting the carrier over a supporting surface for horizontal movement in all directions parallel to said surface so that work may be performed by the machine tool as a consequence of movement of the carrier relative to a work piece in the working zone, and a power driven tool element comprising an endless saw band mounted on the carrier with one stretch thereof constrained to linear travel along a vertical path through the working zone, characterized by: upper and lower saw guides in which the saw band is slidably but nonrotatably received; means mounting one of said guides on each arm of the carrier for rotation on a vertical axis coincident with the cutting edge of said stretch of the saw band; handle means mounted on the carrier for rotation in opposite directions; means drivingly connecting said handle means with both saw guides so that the latter may be rotated simultaneously in the same direction by the handle means to effect twisting of that portion of the hand between the guides and cutting by the saw band along an irregular line; and power operated means for propelling the carrier in a tool feeding direction relative to a work piece between the carrier arms, comprising a traction wheel on the carrier with its periphery in tractive engagement with the supporting surface, means mounting the traction wheel on the carrier for swiveling movement coaxially of the saw guides and for rotation about a horizontal axis intersecting the swivel axis of the wheel, means drivingly connecting the traction wheel with said saw guides so as to constrain the guide wheel to swiveling motion in unison with rotation of the saw guides and in the same direction that the saw guides are rotated by the handle means, and a motor drivingly connected with said traction wheel for rotating the same about its horizontal axis.

2. The machine tool set forth in claim 1 further characterized by the fact that said handle means is mounted on and drivingly connected with the upper one of said saw guides.

3. A machine tool of the type comprising a C-shaped carrier having spaced apart upper and lower arms defining a working zone therebetween, with a power driven tool element thereon constrained to travel linearly along a vertical path through the working zone, and wherein the carrier is mounted over a horizontal supporting surface for movement in all directions parallel to said surface so that work is performed by the tool element as a consequence of movement of the carrier relative to a work piece in the working zone, characterized by: the fact that the tool element is an endless saw band having one stretch constrained to travel along said vertical path; the provision of upper and lower guides for the saw band mounted on the carrier arms and constrained to rotate in unison on a common vertical axis coincident with the cutting edge of said stretch of the saw band, said guides being slidably but nonrotatably connected to the saw band so that rotation of the guides twists that portion of the hand between them relative to the carrier; the provision of a power driven traction wheel on the carrier having its periphery in tractive engagement with the supporting surface; the provision of means mounting the traction Wheel for bodily turning movement in unison with and in the same direction as the saw guides, about a vertical axis coincident with the cutting edge of said stretch of the saw band and intersecting the axis of wheel rotation; and the provision of handle means mounted on the carrier for imparting rotary motion in unison to the saw guides and the traction wheel.

4. In a machine tool, the combination of: an upright C-shaped frame having spaced upper and lower arms between which work to be acted upon may be received; means mounting the frame for bodily horizontal tool feeding movement in all directions over an upwardly facing supporting surface; an elongated power driven tool element on the frame extending vertically. across the space between its arms, said tool element having a laterally facing. cutting edge extending along the length thereof so that the tool element performs its cutting function by lengthwise movement thereof relative to the frame as tool feeding motion is imparted to the frame, provided that the cutting edge of the tool element faces in the direction of such tool feeding motion; means constraining the tool element to travel along a vertical path across said space comprising upper and lower guides in which the tool element is non-rotatably received; means mounting said guides on the arms of the frame for rotation on a vertical axis coincident with said path; means connecting said guides to constrain the same to rotate in unison whereby rotation of the guides effects turning of the tool element in its path relative to the frame to provide for orientation of the tool element to face its cutting edge in whatever direction tool feeding motion must be imparted to the frame to effect cutting of a selected portion of the work; a wheel supporting member mounted on the lower arm of the frame for turning motion about a vertical axis common to that of said guides; power operated means for imparting tool feeding motion to the frame in the direction in which the cutting edge of the tool element faces comprising a traction wheel mounted on said wheel supporting member for bodily turning motion therewith and for rotation about a horizontal axis with the periphery of said wheel in position to have tractive engagement with an upwardly facing supporting surface beneath the lower arm of the frame; means connecting the wheel supporting member with said guides to constrain the wheel supporting member and the traction wheel thereon to turn in unison with said guides about the common vertical axis thereof, said last named means holding the traction wheel with its axis parallel to the cutting edge of the tool element so that regardless of the orientation of the tool element the traction wheel is alwaysin position to impart tool feeding motion to the frame in the proper direction; and control means operatively connected with the rotatable guides to effect rotation of the guides and thus provide for any desired orientation of the tool element and traction wheel.

5. The machine tool set forth in claim 4 wherein the mounting for the wheel supporting member comprises a vertically disposed hollow shaft mounted on the frame in alignment with said path of the too-l element and having the wheel supporting member journalled on its lower end portion; and further characterized by the fact that the power operated means for imparting tool feeding motion to the frame includes an electric motor mounted on the wheel supporting member and drivingly connected to the traction wheel; and by the provision of means for controlling the motor including a helically coiled insulated conductor extending longtudinally through the hollow interior of the shaft.

6. The machine tool set forth in claim 4, wherein said last named means comprises a template having a grooved track in which the guide wheel rides, said track conforming to the outline of the cut to be made in a work piece by the saw.

7. The machine tool set forth in claim 4, wherein said last named means comprises a reversible motor drivingly connected with the guide wheel to impart turning motion thereto in one direction or the other about its vertical axis, a tracer device adapted to engage an edge of a template shaped to correspond to the cut to be made in a work piece by the saw, and motor control means operated by said tracer.

8. The machine tool set forth in claim 7, wherein said reversible motor is of the hydraulic type, and wherein said motor control means comprises a reversing and metering valve element actuated by said tracer device, for governing the operation of the hydraulic motor.

9. In a band saw having a C-shaped frame and an endless saw band mounted thereon and driven to move with one substantially straight stretch thereof travelling across the space between the arms of the frame to saw through work received between the arms, and having means to maintain the saw band under tension; a pair of guide members, one of which is mounted in each arm of the frame for free and unrestricted rotation about an axis common to that of the other member, and for coaction with said stretch of the band at locations spaced apart lengthwise thereof and from the ends of said stretch so that that portion of the stretch which extends between the guide members constitutes the work performing portion of the band; means on the rotatable guide members slidingly gripping the opposite faces of the saw band whereby rotation of the guide members in unison about their common axis twists the work performing portion of the saw band therebetween relative to the end portions of said stretch and to the frame to thereby provide for orientation of said work performing portion of the saw band as required to effect sawing along an irregular contour line upon relative feed motion between the frame and a work piece in position between the guide members; manually actuatable handle means mounted on the frame for back and forth movement relative to the frame; and means providing motion transmitting driving connections between the handle means and said rotatable members whereby actuation of the handle means is translated into rotation of the rotatable guide members in unison and twisting of the work performing portion of the band relative to the frame.

10. The band saw set forth in claim 9 wherein the work performing portion of the saw band is disposed vertically and the frame is movable horizontally in all directions over an upwardly facing supporting surface, relative to a work piece to be sawed, to enable the work performing portion of the saw band to be brought into engagement with different selected areas of the work piece without having to move the work, and further characterized by: the provision of steerable power driven means having tractive engagement with said upwardly facing supporting surface for imparting feed motion to the frame in a direction to engage the cutting edge of said work performing portion of the saw band with work to be sawed; and means connecting the handle means with said steerable power driven means whereby steering motion is imparted to the latter in synchronization with twisting of the work performing portion of the saw band by the handle means to assure feeding of the saw band into the work in the desired direction.

11. The band saw set forth in claim 9 further characterized by: means mounting the frame for free horizontal movement in all directions over an upwardly facing supporting surface, and with the work perform ing portion of the saw band disposed vertically; a traction wheel; means mounting the traction wheel on the frame with its axis horizontal and for bodily swiveling motion about the common axis of said rotatable guide members, and with the wheel disposed to have tractive engagement with said supporting surface; and means drivingly conmeeting the traction Wheel with the rotatable guide members, with the axis of wheel rotation normal to the faces of the work performing portion of the saw band, so that the traction wheel is constrained to swivel bodily with the work performing portion of the saw band as it is twisted by the rotatable guide members to thus at all times maintain the axis of rotation of the traction wheel normal to the faces of the work performing portion of the saw band; and a motor drivingly connected with the traction wheel to rotate the same on its horizontal axis in a direction to impart feed motion to the frame and thereby efiect proper sawing engagement between the cutting edge of said work performing portion of the saw band and the work.

12. In a band saw having a C-shaped frame and an endless saw band mounted thereon and driven to move with one substantially straight stretch thereof travelling across the space between the arms of the frame, and having means to maintain the saw band under tension; coaxial tubular members encircling said stretch of the band at locations spaced apart lengthwise thereof and from the ends of said stretch, the portion of the stretch which extends between said tubular members being the work performing portion of the band; means freely rotatably but non-longitudinally movably mounting the tubular members in the arms of the frame for unrestricted rotation about their common axis; means carried by said tubular members to turn therewith and having jaws thereon slidingly gripping the opposite faces of the saw band so that rotation of the tubular members in unison about their common axis provides for twisting of the work performing portion of the saw band relative to the end portions of said stretch of the band and to the frame and orientation of the work performing portion of the saw band as required to effect sawing along an irregular contour line upon relative feed motion between the frame and a work piece in position between the tubular members; means connecting said tubular members to constrain the same to rotate in the same direction and in unison; and handle means on one of said rotatable tubular members whereby both of the tubular members may be rotated in unison.

1 3. The band saw set forth in claim 12 further characterized by the provision of means mounting the frame for horizontal motion in all directions, and with the work performing portion of the saw band disposed vertically.

14. A machine tool of the type comprising a C-shaped carrier mounted over a supporting surface for horizontal movement in all directions parallel to said surface, with a power driven tool element thereon having a work performing portion constrained to travel linearly along a vertical path through a working zone between the arms of the carrier, characterized by: spaced tool guiding members which are mounted on the carrier to rotate about a fixed common vertical axis coincident with the work performing portion of the tool element and are nonrotatably connected with the tool element so that the work performing portion of the tool element may be turned in its path by rotation of the tool guiding members in unison; power operated means for imparting horizontal tool feeding motion to the carrier, comprising means on the lower portion of the carrier providing a double acting hydraulic cylinder having a piston rod reciprocable lengthwise on a vertical axis coincident with the work performing portion of the tool element and projecting downwarly from the cylinder toward the supporting surface; a wheel supporting member mounted on the lower end portion of the piston rod for rotation about the axis thereof but constrained to move up and down with the piston rod during operation of the cylinder; a traction wheel carried by the wheel suporting member for rotation on a horizontal axis intersected by the axis of the piston rod and to turn bodily with the wheel supporting member about the axis of the piston rod, said traction wheel being tractively engageable with the supporting surface; means for imparting such turning motion to the wheel supporting member and the traction wheel thereon, including handle means drivingly connected with the wheel supporting member and with the tool guiding members so that the latter turn in unison with one another and with the traction wheel; and a motor carried by the wheel supporting member and connected with the traction wheel to impart rotation to the wheel about its horizontal axis, whereby the carrier may be moved horizontally in a direction under the control of the handle means to feed the work performing portion of the tool element into a work piece in the working zone, as a consequence of operation of the motor whenever fluid under pressure is admitted into said hydraulic cylinder to elfect downward extension of the piston rod and tractive engagement of the traction wheel with the supporting surface over which the carrier moves.

References Cited in the file of this patent UNITED STATES PATENTS 2,693,737 Smith Nov. 9, 1954 2,705,510 Stocke Apr. 5, 1955 2,774,131 Crane Dec. 18, 1956