US3620634A

US3620634A - Skiving machine

Info

Publication number: US3620634A
Application number: US836348A
Authority: US
Inventors: Herbert L Sullivan
Original assignee: Martin Marietta Corp
Current assignee: Martin Marietta Corp
Priority date: 1969-06-25
Filing date: 1969-06-25
Publication date: 1971-11-16
Anticipated expiration: 1988-11-16

Abstract

A machine for successively forming a plurality of access holes in a flexible electrical harness or similar type electrical device. The access holes are formed through an outer insulative covering which is laminated to one side of a copper or like conductive material circuit pattern. The access holes are formed by a rotating multipronged cutting blade mounted on the lower extremity of a simultaneously rotatable and vertically movable spindle which has a micrometer dial attached to its upper end in such a manner as to enable the adjustment of the depth of penetration of the blade into the insulation coating. The cutting head assembly of the machine comprises a spring biased pressure foot mounted in floating relation to the blade and used to engage and maintain the harness in proper position while the access hole is being formed.

Description

United States Patent Inventor Herbert L. Sullivan Orlando, Fla. App]. No. 836,348 Filed June 25, 1969 Patented Nov. 16, 1971 Assignee Martin Marietta Corporation New York, N.Y.

SKJIVING MACHINE 10 Claims, 8 Drawing Figs.

US. 408/82, 408/95, 408/207 Int. Cl. B23b 41/00, B23b 49/00 Field of Search 77/5, 34.5,

556, 69; 90/11, ll.l;408/82 Primary Examiner-Francis S. Husar Attorneys-John Orman, Julian C. Renfro and Gay Chin ABSTRACT: A machine for successively forming a plurality of access holes in a flexible electrical harness or similar type electrical device. The access holes are formed through an outer insulative covering which is laminated to one side of a copper or like conductive material circuit pattern. The access holes are formed by a rotating multipronged cutting blade mounted on the lower extremity of a simultaneously rotatable and vertically movable spindle which has a micrometer dial attached to its upper end in such a manner as to enable the adjustment of the depth of penetration of the blade into the insulation coating. The cutting head assembly of the machine comprises a spring biased pressure foot mounted in floating relation to the blade and used to engage and maintain the harness in proper position while the access hole is being fonned.

FIG. 6 F/G. 7

W 72/ xxoo O09 SHEET 1 [IF 2 OOOOOO\ PATENTEDunv 16 I97! \NANNA HERBERT L. SULLIVAN 94; (9M. AGENT rlllllllll PATENTEBrmv 1s l97| SHEET 2 [IF 2 INVENTOR HERBERT L. SULLIVAN gwm AGENT sxrvmc MACHINE BACKGROUND OF THE INVENTION 1. Field of the Invention The subject invention relates to a machine designed to form one or more access holes at predetermined locations in various types of electrical apparatus such as a flexible electrical harness or flat cable wherein a copper or like conductive material circuit is laminated in a sandwichlike fashion between two extremely thin outer sheets of insulation material made from polyamid material or the like. Additionally, the machine may be used to provide access holes to expose con,- ductive pads located at various depths in a rigid multilayer circuit board. The access holes are formed by removing a predetermined portion of an outer insulative sheet only so as to expose the copper or conductive pad of circuitry to direct contact with a connecting pin and a solder connection.

2. Description of Prior Art:

The use of flex harness, flat cables or like electrical apparatus comprising a conductive pad of circuitry laminated between two or more outer insulative coatings or sheets, obviously necessitates that direct contact be obtained between the internal conductive pad and a plurality of connector or contact pins. A number of prior art techniques have attempted to provide an easy means of establishing access to the enclosed conductive pads through the insulative sheets. The commonly practiced techniques used prior to the present invention included a number of disadvantages such as high cost, unreliable connections and inaccurate fonning of access holes to the conductive pad through the insulative covering.

One early prior art practice in fabricating a flex harness included the installation of metallic eyelets which when installed provided a metallic passageway completely through both the outer insulative coverings and the internal conductive pad. Fabrication of flex harness by this method included punching a hole in one insulative coating and the conductive pad, fitting the eyelet in the hole, soldering the eyelet in the hole, soldering the eyelet to the pad and then laminating the outer covering to the side of the conductive pad last soldered to the eyelet. However, this structure resulted in a tendency of the last applied outer insulative cover to separate and bubble up from the solder connection. Also, in that there was a very tight fit between the eyelet and the connecting pin, there was a tendency for the connecting pin to break in the presence of vibration. The eyelet method also suffered the additional problem of excessive fabrication time and cost of production.

The method next most commonly used comprised the forming of access holes in the insulation covering and served to eliminate the use of eyelets. However, problems arose in determining the most economical and efficient manner of forming the access holes. One commonly known method included the use of punch templates wherein a sheet of insulation material was applied to an associated template and holes were punched through the sheet at predesignated locations. Similartemplates were used to fabricate the holes in the conductive pads. After all holes were formed the insulative and conductive layers or sheets were then laminated. Problems arose in the proper alignment of holes in all of the layers. In addition, any change in a design which constituted a different pattern or location of one or more holes necessitated the entire reworking of the individual templates used. This of course added to the time and production cost in fabricating new flex harnesses or reworking old ones. In this process the actual access holes were formed by clearing away the insulative coating from the conductive pad of circuitry by hand tools. The inefficiency and inaccuracy of this method are obvious and result in relatively unreliable, poor quality products.

SUMMARY OF THE INVENTION As previously referred to, access holes are needed in flex harnesses or similar electrical devices which comprise a conductive pad of circuitry enclosed in an insulative coating or consequently high film. These access holes, as the name indicates, provides access to the conductive pad of circuitry through the insulative covering which envelops the conductive pad. The access holes themselves are formed by the removal of a portion of insulative covering at predetermined areas of the conductive pad or circuitry. These access holes define exposed areas of the conductive pad of circuitry which are maintained in direct contact with cooperating connector pins on which the flex harness is mounted. The subject "skiving" machine is designed toform these access'holes and thereby provide sufficient exposure of the conductive pad to insure proper contact between the connecting pins and the conductive pad of circuitry. The subject machine is designed to be capable of forming the access hole by performing a skiving action on any predetermined portion of the insulative material of the flex 'hamess regardless of any predetermined pattern olaccess holes. This particular feature allows the rapid and inexpensive reworking of a previously fabricated flex harness in that any number of access holes may be added at any location on the harness, thereby eliminating a great amount of time and expense in the fabrication of redesigned flex harnesses.

The access holes are formed by a skiving action which refers to a peeling" away of layers of insulation and is accomplished by means of rotating double-pronged cutting blade. The operating position of the blade is adjustable relative to the harness so as to allow penetration of the blade to a predetermined depth into the'insulation covering on the flex harness. This double-pron'ged cutting blade is mounted within a cutting head assembly and is secured to one end of a spindle. The cutting head assembly includes a spring biased pressure foot surrounding the blade and serving to hold and maintain in proper position the area on the flex harness surrounding the access hole to be formed. The pressure foot is mounted in floating relation to the cutting blade and moves relative to the longitudinal axis of the cutting blade by means of the biasing spring which allows the pressure foot to move upward toward the lower extremity of the spindle. This upward movement of the pressure foot is caused by the pressure foot engaging the top insulative covering on the harness when the cutting-head assembly is moved downward into operative position so as to bring the cutting blade into skiving relation to the flex harness.

It will be recognized by those skilled in the an that a main difficulty of forming access holes in the outer insulation of a flex harness is due to the thinness of the insulative material. This extreme thinness necessitates great accuracy in determining to what depth a cutting blade will penetrate the flex harness in that only the insulative material and not the conductive pad is intended to be skived away. To overcome this difficulty the subject machine precisely regulates the depth of penetration of the cutter blade into the insulative material of the harness by adjustably controlling the vertical displacement of the spindle. This is accomplished by means of a micrometer dial which cooperates with both the upper portion of the spindle and the machine frame. Consequently, in operation, the vertically mounted spindle, after being properly adjusted to the exact depth of cut, is capable of simultaneous rotatable and vertical movement within the frame of the machine. This enables the cutting blade attached to the lower portion of the spindle to perform a skiving" action on only the extremely thin insulative material which is laminated to the conductive pad of circuitry.

It is of course obvious to one of ordinary skill in the art that the skiving machine of the present invention can also be used in fabricating access holes in electrical apparatus other than flexible harness, such as flat cables and rigid multilayer printed circuit boards or any electrical apparatus wherein exposure of a conductive material pad through the surrounding insulative material is desired.

The skiving machine of the subject invention overcomes the above-noted problems and disadvantages which are prevalent in prior art methods and apparatus used to fabricate access holes in electrical apparatus such as flex harness. More specifically, the subject machine is capable of the skiving" away of extremely thin insulation material to any depth and at any location on a flex harness or similar electrical device thereby providing an extremely versatile, inexpensive and time saving method of fabricating flex harness. In addition, the subject machine produces a clearly defined, uniform exposed area of conductive material so as to insure a secure and intimate contact between connecting pins and conductive circuitry pads surrounded by the insulative material. This desired versatility is not present in known prior art methods described above, and consequently constitutes a great advantage of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The subject invention will be described in detail with reference to the following drawings showing the structural elements of the machine of the subject invention and their functional relation to one another consistent with the desired operation of the subject machine:

FIG. I is a perspective view of the subject invention during fabrication of a typical flex harness;

FIG. 2 is a front plan view including partial cut away views of the subject machine;

FIG. 3 is a side plan view of the subject skiving machine including cut away views showing the internal arrangement of various structural elements;

FIGS. 4 and 5 are partial sectional views of the cutting head assembly and pressure foot shown in open and closed position, respectively;

FIGS. 6 and 7 are front and side views, respectively, of one embodiment of the blade used in the machine of the present invention; and

FIG. 8 is an enlarged detail view of the cutting portion of the blade of the machine.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT FIG. 1 shows the skiving machine generally indicated at 10 and comprising a main machine frame 12 which generally supports the various structural elements of the machine in cooperating relation to one another. As shown, the machine of the subject invention is approximately the size of a conventional bench type drill press and is designed to fabricate a flexible electrical harness 14 commonly known in the art as a flex harness." The flex harness 14 is positioned in a designated position on work table 16 beneath the cutting head assembly generally indicated at 18. The operation of the machine of the subject invention will be described in greater detail later with specific reference to the structural elements of the machine. Generally, however, the cutting head assembly 18 is mounted on an elongated spindle 26 within the machine frame 12. A spindle adjusting means in the form of a graduated micrometer dial and cooperating locking nut is generally indicated at 20, and serves to adjustably control the maximum displacement of the cutting head assembly 18 from the machine frame 12, thereby precisely controlling the depth of cut or skiving" to be made on the flex harness 14. After setting of the spindle adjusting means the operator would move the spindle and attached cutting head assembly 18 down into cutting or operating position by means of hand knob assembly generally indicated at 22. As shown in FIG. '1, the flex harness 14 is designed to pass beneath the cutting head assembly 18 and be properly positioned on worktable 16 by means of a pilot pin 17 or like positioning means (FIGS. 2 and 3) extending through prepunched holes 15 in the flex harness. This structure will be more clearly described in detail with specific reference to FIGS. 4 and 5.

Turning now to the specific structural elements and their functional relationship, FIGS. 2 and 3 show a vertical casing 24 mounted within machine frame 12 such that vertical longitudinal movement of the vertical casing 24 is permitted by means of conventional longitudinal bearings (not shown) arranged at proper locations throughout frame 12. The centrally located spindle 26 is mounted within the vertical casing 24 such that rotational movement of spindle 26 is permitted by means of

rotational bearing assemblies

28 and 39. Rotational movement is imparted to the spindle 26 by means of a V-pulley hub member 30 mounted to the upper extension of spindle 26. The hub member 30 is driven by V-belt 32 which along with V-pulley hub member 34 forms part of the drive assembly cooperating with electric motor 36. A shaft 38 is connected to electric motor 36 by means of a conventional gearing arrangement generally indicated at 40. As clearly shown in both FIGS. 2 and 3, the driving V-pulley hub member 34 is attached to driven shafi 38. As outlined above, driving pulley 34 drives V- belt 32 which in turn drives V-pulley hub member 30 which in turn causes rotation of spindle 26.

As previously presented, spindle 26 is mounted within vertical casing 24 such that rotational movement of spindle 26 relative to vertical casing 24 is allowed. Spindle 26 is secured to vertical casing 24 by a pair of threaded cooperating nuts 41 secured to the upper extension of spindle 26. While allowing rotational movement of spindle 26, this structural arrangement prohibits the relative longitudinal movement between vertical casing 24 and spindle 26. Consequently, any longitudinal movement of vertical casing 24 results in the longitudinal movement of spindle 26 in that spindle 26 is fixedly mounted within vertical casing 24 in such a manner as to allow rotational movement only of spindle 26 relative to casing 24. As can be seen from the functional relationship between V- pulley hub 30 and spindle 26 as explained above and depicted in FIGS. 2 and 3, movement of spindle 26 along its own longitudinal axis results in the vertical movement of pulley 30 and a vertical displacement of the portion of V-belt 32 in contact with pulley 30. The amount of vertical displacement of pulley 30 and belt 32 is sight because of the relatively small distance between cutting head assembly 18 and worktable 16 and consequently will not aflect the driving action of V-pulley hub 30 and flexible V-belt 32.

Integrally attached to the lower portion of spindle 26 is a socket portion 42 designed to have a portion of the cutting head assembly 18 mounted therein. FIGS. 4 and 5 are partial sectional views disclosing in detail the structural elements of the cutting head assembly and the mounting relationship of socket 42 to cutting head assembly 18.

More specifically, the cutting head assembly 18 comprises a blade casing 44 having its upper portion received within socket 42 and secured therein by means of setscrew 46. In

order to prohibit relative rotational movement between blade casing 44 and socket 42, a keying portion or ridge 48 may extend from the interior wall of socket 42 into a cooperating groove or the like (not shown) on blade casing 44. The cutting blade 50 is removably mounted within a central channel of the blade casing 44 by means of

setscrews

52 and 54. Movably mounted in a "floating" manner on the lower portion of blade casing 44 is pressure foot 56. A biasing means in the form of a coil spring 58 has one end mounted in annular groove 60 in the bottom surface 61 of the annular flange 62 on blade casing 44 and the other end arranged between the interior walls 64 of pressure foot 56 and the blade casing 44. The coil spring 58 allows the floating action of the pressure foot relative to the blade 50 and the remainder of the cutting head assembly in that the pressure foot is allowed to move in a longitudinal direction relative to the blade 50, spindle 26, and blade coping 44. Furthermore, as spindle 26 rotates, spring 58 causes rotation of pressure foot 56 due to frictional engagement of the spring with the pressure foot. The pressure foot 56 includes a channel 66 and aperture 68 through which the blade 50 extends from the pressure foot 44 when the pressure foot is forced against the biasing force of coil spring 58 so as to close the gap or space between the upper peripheral edge of pressure foot 56 and the lower surface 61 of flange 62. Longitudinal movement of pressure foot 56 relative to blade cas ing 44 is permitted in that the pressure foot 56 is attached to the blade casing 44 by means of setscrew 70 extending through the wall of pressure foot 56 into an annular groove 72 which allows the sliding of setscrew 70 within the limits defined by the annular groove 72.

When the pressure foot 56 is in its normal or open, inoperative position as shown in FIG. 4, the lower or cutting portion of blade 50 is surrounded by the pressure foot 56. FIG. 5 shows pressure foot 56 in its operative, closed position wherein blade 50 is caused to extend out through channel 66 and aperture 68 as the pressure foot 56 is forced against the biasing force of spring 58 and toward the lower peripheral edge 61 of annular flange 62 as explained above. The pressure foot 56 is driven upward into this closed position relative to annular flange 61 due to the lip 74 engaging the outer insulative coating 76 of flex harness 14. FIG. 5 further depicts a typical flex harness generally indicated at 14 comprising outer'insulative coating 76, conductive pad of circuitry 78 and lower outer insulative coating 80. The maximum distance blade 50 may extend out of the pressure foot 56 is determined by setscrew 52 and this distance may be adjusted dependent upon the dimensions of the material being fabricated.

FIGS. 6, 7 and 8 disclose the structure of the cutting blade 50 which includes a flat 55 formed on the upper portion of blade 50 and designed to cooperate with setscrew 54. A multipronged configuration is formed on the lower portion of the blade 50 and constitutes the cutting or skiving portion of the blade. In the preferred embodiment shown in FIGS. 7 and 8, the blade 50 includes two

prongs

82 and 84 integrally formed to the body 50 of the blade and arranged in symmetrical spaced relation to one another. The lower extremities of both

prongs

82 and 84 are formed into cutting portions 86.and 88 which would normally be referred to as cutting edges. However, due to the extreme thinness of the insulative coating 76, cutting

portions

86 and 88 are each ground flat such that the cutting flats" 86 and 88 lie in a single plane substantially perpendicular to the longitudinal axis of blade 50. This is clearly shown in the enlarged detailed view of FIG. 8 where the cutting flats" are indicated clearly at 86 and 88. This flatness is necessary due to the extreme thinness of the insulative covering 76 making it difiicult'to form a properly shaped access hole. Shaping the cutting

portion

86 and 88 of each prong into a flat configuration insures a uniform cut and a properly shaped access hole in the insulative material 76. Further inregard to blade 50, prongs 82 and 84 are tapered down to cutting

flats

86 and 88. This taper on the prongs provides space for the excess insulative-material which is-skived from access hole 17 to pass between the blade and the interior of the pressure foot and out aperture 92.

As noted above, the prongs'82 and 84 are symmetrically spaced from one another and consequently partially define a channel 90 designed to receive a flex harness positioning means in the form of a pilot pin 17 (FIGS. 2 and 3)mounted on worktable 16. The precise function of the pilot pin 17 relative to the flex harness will be described in greater detail with relation to the operation of the subject machine.

To operate the subject machine an operator throws .flip switch 47 mounted on terminal box 49 connected to electric motor 36 by cable 45. This activates electric motor 36, causing gearing assembly 40 to initiate operation of the driving assembly comprising pulley 34, V-belt 32 and driven pulley 30, thereby causing rotation of spindle 26. After rotation of spindle 26 has begun, the machine is of course ready to perform a skiving action which-may be initiated by the cutting head assembly 18 being loweredinto operative cutting position by an operator manually moving hand knob assembly 22. Hand knob assembly 22 is connected to vertical casing 24, within the machine frame 12 in any conventional manner consistent with the functional operation of the subject machine. Consequently, as hand knob assembly 22 is rotated in the prescribed direction, vertical casing 24 and-spindle 26 move downward, thereby lowering the attached rotating cutting head assembly 18 into operative skiving position relative to flex harness'14 which is positioned by means of pilot pin 17 on worktable 16 (FIG. 1

Referring specifically now to FIGS. 2 and 3, the spindle adjusting assembly 20 in the fonn of a micrometer dial 21 and lock nut 23 are connected to the vertical casing 24 by means of an internal hub 25 which is itself attached to vertical casing 24 by means of one or more setscrews 27 positioned to engage a peripheral groove 29 in the top portion of the vertical casing 24. Both micrometer dial 21 and lock nut 23 engage the internal hub 25 by means of cooperating threads arranged on the interior wall of themicrometer dial 21 and lock nut 23 and on the exterior walls of intemai hub 25. Due to this threaded engagement, both the dial 21 and the lock nut 23 are allowed to move in a vertical direction relative to the internal hub 25 which is fixed to the vertical casing in the manner described above. The micrometer dial 21 serves as a spindle adjustment means in that upon downward movement of the vertical casing 24 and spindle 26, the bottom surface 31 of the micrometer dial 21 comes into abutting relation with the top surface 33 of machine frame 12. Consequently, the amount of vertical displacement between the blade 50and the casing 12 is equal to the'distance between surfaces 31 and 33 in that the vertical movement of vertical casing 24, spindle 26 and blade 50 is stopped upon the engagement of the cooperating surfaces 31 and 33 of dial 25 and frame 12 respectively. Rotation of micrometer dial 21 on internal hub 25 determines the position of the dial on the hub relative to frame 12. Accordingly, the

lower portion'of micrometer dial is graduated as at 35 and a reference indicator 37 is attached to an appropriate point on frame 12 so the dial can be rotated and consequently positioned to an exact degree.

In operating the device, flex harness 14 is first prepunched with clearance holes 15 (FIG. 5) at each point on the flex harness 14 at which it is desired to place an access hole 19 in order to expose an annular portion 77 of the conductive pad of circuitry 78. This prepunching operation and method of forming clearance holes 15 is generally well known in the art and forms no ,part of the present invention. The prepunched hole 15 is designed to fit over pilot pin 17 on worktable 16 so as to properlyv position the flex harness 14 as it is being fabricated. Once the flex harness 14 is in position, the micrometer dial21'is set by means of graduated area 35 (FIG. 3) cooperating with reference indicator 37. This of course determines the depth of penetration of blade prongs '82and 84 such-that the cutting

flats

86 and 88 will extend through the insulative coating 76 but not into the conductive pad 78. This relationship'is clearlyshown in FIG. 5.

After proper setting of micrometer dial 21, lock nut 23 is threaded down in place so as to prohibit unintended movement of the dial 21. The flex harness 14 is then positioned on pilot pin 17 by means of the prepunched clearance holes 15. To form any access hole 19 to the vertical casing 24, spindle 26 and cutting head assembly 18 are all lowered by manual operation of hand knob assembly 22 until lip 74 engages flex harness 14. The. engagement of lip 74 with the outer insulative covering 76 forces the area of the flex harness surrounding hole 15 into fixed position against worktable 16 (FIG. 1). This maintains the secured area of the flex harness 14 in an immovable position so that rotating blade 50provides'a smooth peripheral surface on access hole 19 as it is being formed. in other words, the pressure foot serves to prevent an undesirable displacement of the harness 14 atsuch time as it is contacted by blade 50, this arrangement thus prevents the formation of an access hole having rough edges. Upon engagement of lip 74 with insulative coating 76 the pressure foot 56 is pushed backtoward annular flange 62 thereby closing the gap between surfaces 61 and 65 on the blade casing'54 and pressure foot 56, respectively. This movement of pressure foot 56 allows the lower portion of the prongs or cutting

flats

86 and 88 to extend out of pressure foot 56 and penetrate insulative coating 76 up to conductive pad 78. The rotation of spindle 26 and therefore blade 50 causes a skiving action to be performed on the outer insulative coating 76, thereby forming an access hole 19 having a diameter equal to the diameter of the cutting blade 50. The excess insulative particles skived from coating 76 pass up through aperture 68 and out through a waste passage 92. The flex harness is maintained in proper position by pilot pin 17 extending up through clearance hole and through channel 90 between

prongs

82 and 84 of blade 50, as the blade engages the flex harness 14 after it extends out of pressure foot 56.

What I claim is:

l. A machine of the type utilizing a skiving action to form holes on a material being fabricated, the machine comprising a machine frame, a vertical casing mounted for longitudinal movement relative to the frame, a spindle rotatably attached to the vertical casing such that the spindle may simultaneously move in a rotational and longitudinal direction relative to the machine frame, a cutting head assembly attached to the spindle, the cutting head assembly including a blade for directly acting upon such material, a pressure foot, and a blade casing, said pressure foot floatingly attached to said blade casing by a spring biasing means such that said pressure foot is movable in a longitudinal direction relative to said blade, said pressure foot being arranged to make contact with the material being fabricated before the blade does, said pressure foot being arranged to apply pressure during continued movement of said blade toward the material, latter movement being a spring bias-increasing direction, with the pressure thus applied serving to hole the material in a desired relationship to said blade, and material positioning means attached to said machine frame in spaced cooperating relation with said cutting head assembly and serving to properly position the material being fabricated.

2. A. skiving machine having a worktable and operable to remove by a form of cutting action, only selected amounts of material from a workpiece placed on said worktable, comprising a cutting blade mounted for rotation about its longitudinal axis above the worktable, and a spring biased pressure foot disposed in essentially surrounding relation about said blade, but with an opening in its lower end, said blade having a cutting portion at its end nearest said worktable, and able on occasion to extend through said opening, said blade being mounted upon a spindle designed to be driven in rotation, means for providing relative motion between said spindle and said worktable, so that the cutting portion of said blade can be caused to approach and to contact a workpiece disposed on said worktable of said machine, a portion of said pressure foot adjacent said opening in its lower end being caused at the time of relative motion to first come into contact with the workpiece to be cut, with thereafter the spring bias of said pressure foot being overcome to such an extent that the cutting portion of said blade can extend through said opening and come into cutting contact with the workpiece so as to remove controlled amounts therefrom, said pressure foot serving to hole the workpiece firmly upon said worktable during such cutting, and material positioning means attached to said worktable in spaced cooperating relation to said cutting blade and serving to properly position the workpiece.

3. A cutting machine of the type utilizing a skiving action to form holes in a material being fabricated, the machine comprising a machine frame, a spindle rotatably mounted on the frame, means mounted on the frame to allow both rotational and longitudinal movement of the spindle; a cutter head assembly comprising a cutting blade having a plurality of longitudinally extending prongs formed on the end thereof, a spindle-adjusting means mounted on the spindle to regulate the depth of the penetration of the blade into the material being fabricated, said blade further comprising an elongated channel partially defined by the plurality of longitudinally extending prongs, the elongated channel extending into the cutting blade along the central longitudinal axis thereof; material positioning means attached to the machine frame in spaced cooperating relation to the cutter head assembly and serving to properly position the material being fabricated, whereby the positioning means is attached so as to extend into the channel of the blade when the blade is in operating posir t A cutting machine as in claim 3 further comprising a worktable attached to the frame, the positioning means comprising a pilot pin mounted on the worktable in cooperating relation to the cutting head assembly so as to extend into the channel of the cutting blade when the blade is moved into operating position.

5-. A cutting machine as in claim 3 wherein the plurality of prongs comprise two longitudinally extending prongs symmetrically spaced from each other on the cutting blade, each of the prongs including a flattened cutting extremity and a tapered portion on each of said prongs terminating at the flattened cutting extremity.

6. The machine as defined in claim 2 in which the cutting end of said blade is in at least two slightly separated portions, disposed generally symmetrically about the longitudinal axis of said blade.

7. The device as defined in claim 6 in which said materialpositioning means is an alignment pin disposed on the worktable of said machine, and fon-ning an alignment means for the workpiece being cut, the cutting portions of said blade being separated sufficiently to allow said pin to enter the area of the blade between said portions as said blade is lowered about said pm.

8. The device as defined in claim 7 in which readily ad justable means are provided are controlling to a precise degree, the amount of material that can be removed from a workpiece by said blade at a given location.

9. The machine as defined in claim 1 in which micrometertype adjustment means are provided so that the depth of cut accomplished by the action of said blade upon the material can be carefully established.

10. The machine as defined in claim 1 in which said material positioning means is an alignment pin disposed in alignment with said spindle and utilized for assisting the positioning of the material in the proper relationship to said blade.

Claims

1. A machine of the type utilizing a skiving action to form holes on a material being fabricated, the machine comprising a machine frame, a vertical casing mounted for longitudinal movement relative to the frame, a spindle rotatably attached to the vertical casing such that the spindle may simultaneously move in a rotational and longitudinal direction relative to the machine frame, a cutting head assembly attached to the spindle, the cutting head assembly including a blade for directly acting upon such material, a pressure foot, and a blade casing, said pressure foot floatingly attached to said blade casing by a spring biasing means such that said pressure foot is movable in a longitudinal direction relative to said blade, said pressure foot being arranged to make contact with the material being fabricated before the blade does, said pressure foot being arranged to apply pressure during continued mOvement of said blade toward the material, latter movement being in a spring bias-increasing direction, with the pressure thus applied serving to hold the material in a desired relationship to said blade, and material positioning means attached to said machine frame in spaced cooperating relation with said cutting head assembly and serving to properly position the material being fabricated.

2. A skiving machine having a worktable and operable to remove by a form of cutting action, only selected amounts of material from a workpiece placed on said worktable, comprising a cutting blade mounted for rotation about its longitudinal axis above the worktable, and a spring biased pressure foot disposed in essentially surrounding relation about said blade, but with an opening in its lower end, said blade having a cutting portion at its end nearest said worktable, and able on occasion to extend through said opening, said blade being mounted upon a spindle designed to be driven in rotation, means for providing relative motion between said spindle and said worktable, so that the cutting portion of said blade can be caused to approach and to contact a workpiece disposed on said worktable of said machine, a portion of said pressure foot adjacent said opening in its lower end being caused at the time of relative motion to first come into contact with the workpiece to be cut, with thereafter the spring bias of said pressure foot being overcome to such an extent that the cutting portion of said blade can extend through said opening and come into cutting contact with the workpiece so as to remove controlled amounts therefrom, said pressure foot serving to hold the workpiece firmly upon said worktable during such cutting, and material positioning means attached to said worktable in spaced cooperating relation to said cutting blade and serving to properly position the workpiece.

3. A cutting machine of the type utilizing a skiving action to form holes in a material being fabricated, the machine comprising a machine frame, a spindle rotatably mounted on the frame, means mounted on the frame to allow both rotational and longitudinal movement of the spindle; a cutter head assembly comprising a cutting blade having a plurality of longitudinally extending prongs formed on the end thereof, a spindle-adjusting means mounted on the spindle to regulate the depth of the penetration of the blade into the material being fabricated, said blade further comprising an elongated channel partially defined by the plurality of longitudinally extending prongs, the elongated channel extending into the cutting blade along the central longitudinal axis thereof; material positioning means attached to the machine frame in spaced cooperating relation to the cutter head assembly and serving to properly position the material being fabricated, whereby the positioning means is attached so as to extend into the channel of the blade when the blade is in operating position.

4. A cutting machine as in claim 3 further comprising a worktable attached to the frame, the positioning means comprising a pilot pin mounted on the worktable in cooperating relation to the cutting head assembly so as to extend into the channel of the cutting blade when the blade is moved into operating position.

5. A cutting machine as in claim 3 wherein the plurality of prongs comprise two longitudinally extending prongs symmetrically spaced from each other on the cutting blade, each of the prongs including a flattened cutting extremity and a tapered portion on each of said prongs terminating at the flattened cutting extremity.

7. The device as defined in claim 6 in which said material-positioning means is an alignment pin disposed on the worktable of said machine, and forming an alignment means for the workpiece being cut, the cutting Portions of said blade being separated sufficiently to allow said pin to enter the area of the blade between said portions as said blade is lowered about said pin.

8. The device as defined in claim 7 in which readily adjustable means are provided for controlling to a precise degree, the amount of material that can be removed from a workpiece by said blade at a given location.

9. The machine as defined in claim 1 in which micrometer-type adjustment means are provided so that the depth of cut accomplished by the action of said blade upon the material can be carefully established.