Abstract:
A machine for precisely cutting and stripping insulated electrical conductors. The depth of cut may be accurately set to accommodate wide ranges of conductor/insulation sizes. The length of the strip may be varied and accurately set without repositioning the entire machine. The machine may be bench mounted to act as a stand alone unit, or it may be mounted on a conveyor type automatic wire cutting and stripping machine. The machine includes a base plate that reciprocates parallel to the insulated electrical conductor to perform the stripping operation. A cutterhead opens and closes over the insulated electrical conductor to perform the cutting operation. The cutterhead comprises a pair of cutterhead slides that are accurately aligned with each other and that precisely reciprocate on a common plate. The cutterhead slides are driven by a dual cam-yoke system. The base plate and cutterhead mechanisms are cushioned at the ends of their respective strokes by a shock absorbing system. The blades are accurately clamped in the cutterhead slides by means of tool holders that are easily locked and unlocked in the respective cutterhead slides.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention pertains to processing insulated electrical conductors, and more particularly to small wire stripping machines. 
     2. Description of the Prior Art 
     The process of cutting and stripping insulated electrical conductors in automatic machinery involves the use of pairs of cooperating blades, such as are disclosed in U.S. Pat. No. 4,577,405. The cutoff and stripping blades are typically clamped within two independent tool holders, with one blade of each pair being clamped in a different tool holder. The tool holders in turn are locked in place on separate opposed slides of a cutterhead mechanism. The cutterhead slides reciprocate toward and away from each other to close and open the blades. Closing the stripping blades forms a nearly perfectly round cutting hole circumferentially over the insulated electrical conductor to slice the insulation. The cutterhead is also translatable parallel to the electrical conductor axis to strip the sliced slug of insulation from the conductor. It is imperative that the closed stripping blades form a hole that closely conforms to the periphery of the conductor being stripped. Any skewness of the blades can result in scraped, nicked, or cut conductor strands. 
     Insulation cutting and stripping force requirements are very different for different size electrical conductors. A machine designed to process relatively large electrical conductors, such as 10 gauge wires, is overdesigned for use on smaller wires, such as 22 gauge wires. Conversely, the life of a machine designed for processing small wires but used for large wires is greatly shortened. Prior cutterheads include numerous levers, toggles, and other types of linkages to produce the necessary cutting and stripping forces. Such mechanisms are generally unsatisfactory for several reasons. They are frequently underdesigned and are prone to excessive deflections when used with heavy wire sizes. The various pivot points quickly wear and become sloppy. In many designs, linkage travel adjustments affect the force transmitted. For example, in one prior machine, an air cylinder rod operates a toggle linkage to open and close the cutterhead. The maximum extension of the cylinder rod determines where the toggle links stop. Accordingly, the force transmitted by the toggle links is a function of the allowed extension of the cylinder rod. Further with toggle mechanisms, if the links are closed past center when closing the cutterhead, the blades will actually open. 
     Other design flaws of prior cutterheads for processing insulated electrical conductors involve the fact that the two tool holders on the cutterhead are entirely independent of each other. The large number of components, such as slides and linkages, make an undesirable stack-up of tolerances unavoidable. Hence, proper alignment between the two independent tool holders is very difficult to achieve. Closely related is the fact that many prior machines utilize cast pieces to hold the cutting and stripping blades. Unfortunately, the casting process does not achieve the close tolerances required to accurately align and hold the blades. 
     The accuracy problem is greatly aggravated by the recent trends in the automotive and electronics industries to use ever smaller gauge conductors and thinner wall insulations. A typical small gauge/thin wall insulated electrical conductor has a conductor diameter of 0.029 inches and an insulation wall thickness of 0.011 inches. With an insulation wall thickness of 0.011 inches, the blades for stripping the insulation from the conductor must be capable of being adjusted to within approximately 0.001 inches. Because 0.001 inches is such a fine resolution, an accurate and rigid mechanical system for clamping and positioning the blades when forming the cutting hole is crucial. 
     Because of the accuracy problem inherent with prior insulated wire processing machines, operators traditionally insert the stripping blades into the machine without actually knowing the size of the cutting hole that will be formed by the closed blades. The operator then strips some test wires. If the blades cut the conductor, he adjusts the blades for a larger cutting hole size; if the blades do not completely cut through the insulation, he adjusts the blades for a smaller cutting hole size. In other words, present practice is to set stripping blades in a trial-by-error fashion. 
     Since different wire sizes generally require different blades and also different strip lengths, frequent changes to the tool holder set-ups are necessary. However, in prior cutterheads, it is difficult and cumbersome to remove and insert both the blades and the spacers that fill the tool holder cavities between the blades. Detailed information on tool holder spacers may be found in U.S. Pat. No. 4,784,024. 
     In many prior wire processing machines, the wire is vertically oriented with a vertical cutterhead. The blades reciprocate along a vertical axis. Scrap removal is a problem in those machines because the scrap insulation slugs tend to fall by gravity onto the lower blades. If that happens, the slugs can become trapped on the lower blades and prevent a good strip of the subsequent wire ends to be processed. 
     Thus, although numerous types of equipment are available for automatically cutting and stripping insulation from insulated electrical conductors, the existing equipment is not capable of meeting modern production requirements. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a convenient and versatile machine is provided that precisely cuts and strips insulated electrical conductors on a high speed basis. This is accomplished by apparatus that includes a counterrotational double cam mechanism that opens and closes a cutterhead and associated processing blades along a common guide plate. 
     The wire processing machine of the present invention is versatile enough to be used either in bench mounted or conveyor mounted applications. In both applications, the machine comprises an elongated base plate to which is mounted a fluid cylinder. The cylinder piston rod is connected to a pair of oppositely facing racks for reciprocating along the base plate. Through suitable gear trains, the racks drive respective cams rotatably mounted in the common plate. The cutterhead includes two cutterhead slides that are driven by respective cams for precisely reciprocating on the common plate. Actuation of the fluid cylinder causes reciprocation of the racks and simultaneous opposite rotations of the cams. Consequently, the cutterhead slides reciprocate toward and away from each other in timed relationship. The common plate assures accurate and permanent alignment between the two opposed and independent slides. 
     Locked to each cutterhead slide is a tool holder. Each tool holder comprises two members joined together for accurately holding the wire processing blades and the associated locating spacers. The blades are clamped in the respective tool holders parallel to each other and in planes transverse to the axis of the insulated electrical conductor to be processed. As the two cutterhead slides reciprocate toward and away from each other, the associated stripping blades on the two tool holders close and open to cooperate with each other to create and dissipate an accurately round cutting hole concentric with the electrical conductor being processed. As the blades close toward each other, their cutting edges slice the insulation through to the conductor. 
     The tool holders are adjustable with respect to the respective cutterhead slides in the directions of blade reciprocation. Therefore, for a given tool holder slide position at the end of the closing stroke, the tool holder can be adjusted to accommodate different blades and wires. Preferably, the tool holder slide adjustment mechanism includes a torque screw that slips after a predetermined force is applied to the blades. In that manner, machine operator strength is not a variable in machine precision, and it is virtually impossible to jam the adjustment mechanism by overtightening. 
     It is a feature of the present invention that the tool holders are very easy to install and remove from the respective cutterhead slides. Ease of operation is achieved by a latch and hand knob. Selective manual rotation of the hand knob causes the latch to lock or unlock the tool holder from the cutterhead slide. Further, the tool holders are fabricated with open tops that enable the machine operator to conveniently see and adjust the blades without hindrance from other machine components. 
     To cushion the impact of the moving components at the ends of the cylinder strokes, the present invention includes two sets of decelerators. As the racks and cutterhead slides approach the ends of their strokes in each direction, the decelerators associated with that direction coact with cooperating stops to cushion the slides. Accordingly, acceleration forces are greatly reduced, which contributes to long machine life and quiet operation. 
     Further in accordance with the present invention, the base plate and the various components mounted on it are reciprocable together in a direction parallel to the axis of the wire being processed. Such motion is required to strip the insulation slugs from the conductor after the stripping blades have closed over and sliced the insulation through to the conductor. Stripping motion parallel to the electrical conductor length is accomplished by slidingly supporting the base plate on a bottom base that is mounted to the bench, conveyor, or other frame member. A pair of precision shafts are spaced above and fastened to the bottom base. The base plate is reciprocatingly supported on the precision shafts by pillow blocks secured to the base plate. 
     To reciprocate the base plate along the bottom base, an actuator may be mounted to the underside of the base plate. The actuator may be a fluid cylinder having a piston rod connected to the bottom base. In that manner, actuation of the cylinder reciprocates the base plate along the precision shafts fastened to the bottom base. Decelerators are employed between the bottom base and base plate for cushioning the moving base plate at the ends of its strokes in at least one direction. To set the length of the stripping stroke, an adjustment mechanism is employed between the base plate and bottom base. 
     Other objects and advantages of the invention will become apparent to those skilled in the art upon reading the disclosure. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1a-1e are a series of schematic diagrams showing the sequence of operations for cutting and stripping insulated electrical conductors. 
     FIG. 2 is a partially broken side view of the wire stripping machine of the present invention. 
     FIG. 3 is a partially broken end view of the wire stripping machine of the present invention. 
     FIG. 4 is a partially broken top view of the wire stripping machine of the present invention. 
     FIG. 5 is a view taken along lines 5--5 of FIG. 2. 
     FIG. 6 is a cross-sectional view taken along lines 6--6 of FIG. 5. 
     FIG. 7 us a cross-sectional view taking along lines 7--7 of FIG. 3. 
     FIG. 8 is a cross-sectional view taken along lines 8--8 of FIG. 4. 
     FIG. 9 is a cross-sectional view taken along lines 9--9 of FIG. 8. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structure. The scope of the invention is defined in the claims appended hereto. 
     For purposes of background, the general procedure for stripping and cutting insulated electrical conductors will initially be discussed. Referring to FIGS. 1a-1e, reference numeral 1 represents a station of a machine for processing an insulated electrical conductor 13 at which one end of the electrical conductor is cut and stripped of insulation. Reference numeral 3 represents a cutterhead. The cutterhead 3 comprises a pair of cutterhead slides 4 and 6, to which are clamped respective cutoff blades 5 and 7 and stripping blades 9 and 11. 
     In the first step of the processing cycle, the cutterhead 3 is indexed in a first stripping stroke in the direction of arrow 15 to a position relative to the electrical conductor 13 typically represented in FIG. 1b. Subsequently, the cutterhead closes in a first cutting stroke in the directions indicated by the arrows 17 and 19 toward the electrical conductor. The cutting blades 5 and 7 cooperate to trim the electrical conductor end by cleanly cutting entirely through the wire and producing a short scrap end 21, FIG. 1c. The stripping blades 9 and 11 close over the electrical conductor so as to slice the insulation, but only as far as the conductor periphery. 
     Next, the cutterhead 3 is translated in a second stripping stroke in the direction of arrow 23 to the position of FIG. 1d. The scrap end 21 is shown schematically in FIG. 1d as moving with the cutterhead and cutoff blades 5 and 7. The travel of the cutterhead in the direction of arrow 23 strips an insulation slug 25 from the electrical conductor 13, thereby exposing the bare conductor 27. The length of the insulations slug 25 stripped from the electrical conductor is equal to the distance L between the operative surfaces of the two pairs of blades, FIG. 1b. 
     Finally, the cutterhead 3 opens in a second cutting stroke in the directions of arrows 29 and 31, FIG. 1d. The cutoff and stripping blades open, and the insulation slug 25 is cleared by mechanical knockouts 33, FIG. 1e. The insulated electrical conductor 13 may then be indexed, as by means of a conveyor schematically illustrated at 35, to carry away the cut and stripped wire and to present another length to the station 1 for processing. The cycle is repeated, again starting at FIG. 1a. 
     GENERAL 
     In accordance with the present invention, processing the insulated electrical conductor 13 is precisely and rapidly performed by a wire stripping machine 37. Looking also at FIGS. 2-5, the wire stripping machine 37 is mounted on a frame member, schematically depicted at 39, that suits that particular application and production requirements. Mounting of the machine to the frame member 39 is by means of a bottom base assembly 41. The bottom base assembly 41 slidingly supports a base plate assembly 43 for reciprocation in the stripping stroke directions of arrows 15 and 23, which correspond with the arrows 15 and 23 in FIG. 1. The base plate assembly 43 supports a cutterhead 3, which corresponds to the cutterhead 3 of FIG. 1. The cutterhead includes slides 4 and 6, which are capable of reciprocating in cutting stroke directions of arrows 17, 29 and 19, 31, respectively, again corresponding with the directions of FIG. 1. Processing blades 5, 7, 9, and 11 are clamped within the cutterhead for cutting and stripping the insulated electrical conductor 13. 
     BOTTOM BASE ASSEMBLY 
     Referring especially to FIGS. 2, 5, and 6, the bottom base assembly 41 comprises an elongated bottom base 45 that is mounted by any suitable means to the appropriate frame member 39. To the bottom base 45 are fastened a pair of parallel precision shafts 47. The shafts 47 are located above the bottom base by respective supports 49, and the shafts and supports are secured to the bottom base by fasteners 51. Slidingly received over the shafts are pillow blocks 53. The pillow blocks 53 are fixed to the underside of the base plate assembly 43 by means of fasteners 56. 
     BASE PLATE ASSEMBLY 
     To reciprocate the base plate assembly 43 in the stripping stroke directions of arrows 15 and 23, a first fluid cylinder 57 is mounted to the underside of a base plate 55. The cylinder 57 may be mounted to the base plate 55 by means of collapsible clamps 58 and associated fasteners 60. In the illustrated construction, the cylinder 57 is double ended, with a front piston rod 59 and a back piston rod 61. The front piston rod 59 is connected to a plate 63 attached to the front end of the bottom base 45 by fasteners 65. Similarly, the back piston rod 61 is connected to a plate 67 attached to the back end of the bottom base by fasteners 69. To provide adequate clearance for the first cylinder and the clamps 58, the bottom base is machined with a longitudinally extending slot 71 therethrough. Actuation of the cylinder 57 causes the base plate assembly to reciprocate along the bottom base in the directions of arrows 15 and 23. In the drawings, the base plate assembly is shown almost at the end of its stroke in the direction of arrow 15. 
     In the preferred embodiment, the base plate assembly 43 is cushioned at the end of the stripping stroke of the cylinder 57 in the direction of arrow 15. For that purpose, the wire stripping machine 37 includes a pair of decelerators 73 mounted to the underside of the base plate 55. The decelerators 73 may be received within a support plate 75 that is fixed to the base plate by means of screws 77. We have found that an Enetrols linear decelerator with a 0.375 inch bore and a 1 inch stroke works very well on the cutting and stripping machine. To provide a coacting member for the decelerators, a stop 79 is fastened to the back end of the bottom base 45 by screws 81. 
     The stop 79 also serves to positively locate the base plate assembly 43 at the end of the strokes thereof in the direction of arrow 15. The positive location is obtained by means of a stop block 83, which is attached to the support plate 75 by screws 85. The stroke of the base plate assembly is limited by the abutment of the stop block 83 against the stop 79. For clarity, a slight clearance C is shown between the stop block 73 and the stop 79. It will be appreciated that the clearance C actually exists immediately before and after the end of the base plate assembly strokes in the direction of arrow 15. 
     To adjust the location of the base plate assembly 43 relative to the bottom base assembly 41 at the end of the base plate assembly stripping strokes in the direction of arrow 15, the wire stripping machine 37 includes a base plate adjustment mechanism 87. The base plate adjustment mechanism 87 comprises a knob 89 that is pinned to a threaded rod 91. The threaded rod 91 is freely supported in an end plate 93, which is fixed to the back end of the base plate 55 by screws 95. The threaded rod engages threads in the support plate 75. The knob 89 and the threaded rod are captured in the end plate 93 by a spacer 97 and a clamp-on collar 99. To permit adjustment of the location of the support plate 75 and thus the stop block 83, the base plate 55 is formed with slots 101 that receive the mounting screws 77. To hold the support plate 75, stop block 83, and decelerators 73 during adjustment when the screws 77 are loose, a pair of guide pins 103 are retained in the end plate 93. The guide pins 103 may be held in place with screws 105. The guide pins 103 pass through closely mating holes in the support plate 75. By loosening the screws 77 and turning the knob 89, the location of the base plate assembly 43 relative to the bottom base assembly 41 at the end of the base plate assembly stripping strokes in the direction of arrow 15 can be quickly and accurately set. Retightening the screws 77 maintains the end setting for precise stripping strokes until the machine operator makes further adjustments. 
     CUTTERHEAD DRIVE MECHANISM 
     Turning again to FIGS. 2-4, the wire stripping machine 37 comprises a drive mechanism 107 for closing and opening the cutterhead 3 in the cutting stroke directions of arrows 17, 19 and 29, 31, respectively. The drive mechanism 107 includes a second fluid cylinder 109 mounted to the top surface of the base plate 55. The piston rod 111 of the cylinder 109 is connected to a front shock support 113. In turn, the front shock support 113 is attached to a slider 115 by screws 117. Accordingly, actuation of the second cylinder causes the slider 115 to reciprocate along the base plate. To provide long life and friction free slider reciprocation, the base plate is formed with a step 119, and a bronze coated wear plate 121 is inserted into the step. The wear plate 121 may be fastened to the base plate step 119 by screws typically represented at 123. To guide the slider on a the wear plate, both of those components are formed with aligned keyways. A key 125 is pressed into the wear plate keyway, and the slider keyway fits over the key with a sliding fit. 
     As with the reciprocation of the base plate assembly 43 on the bottom base assembly 41 described previously, the motions of the slider 115 are cushioned at the ends of the strokes of the piston rod 111. For that purpose, a pair of decelerators 127 are mounted in the front shock support 113. The decelerators 127 may be identical to the decelerators 73. The decelerators 127 coact with a component to be described presently to cushion the slider strokes in the cylinder piston rod extended position. To cushion the slider strokes in the cylinder piston rod retracted position, another pair of decelerators 129 is mounted within a back shock support 131. The back shock support 131 is secured to the base plate 55 by fasteners 133. The decelerators 129 coact with the front shock support 113 to cushion the slider and front shock support at the end of the cylinder retraction strokes, which is the position of the slider and cylinder piston rod 111 illustrated in the drawings. 
     Located above the front end of the base plate 55 is the cutterhead 3. The cutterhead closes and opens in the cutting strokes of arrows 17, 19 and 29, 31 along a common plate 135. The common plate 135 is supported by a pair of brackets 137 fixed to the side edges of the base plate by screws 139. The common plate is attached to the brackets 137 by screws 141, which are best shown in FIG. 7. 
     Looking at FIGS. 3 and 7, a pair of roller supports 142 are joined to the underside of the common plate 135 by screws 144. Near the lower end of each roller support 142 is rotatably mounted a cam follower 146. The cam followers 146 are located so as to loosely restrain the slider 115 against upward movement as it reciprocates along the base plate 55 under the influence of the fluid cylinder 109. Also see FIGS. 2 and 4. 
     In FIG. 3, a centerline 148 is depicted on each roller support 142. The centerlines 148 indicate the longitudinal axes of the two decelerators 127 The roller supports serve as the components that coact with the decelerators 127 to cushion the slider 115 at the ends of the strokes of the piston rod 111 in the extended position. 
     Now turning to FIGS. 2-4, 7, and 8, the drive mechanism 107 for opening and closing the cutterhead 3 further comprises a pair of racks 145. The racks 145 are mounted to the opposite sides of the slider 115 by screws 143. Each rack 145 meshes with a respective idler gear 147 that is mounted for rotation about a vertical axis. Each idler gear 147 is journaled in a bushing 149. The bushings 149 are received in respective upstanding posts 151 fixed to ears 152 that extend oppositely from the side edges of the base plate 55. The idler gears mesh with respective second gears 153. Each second gear 153 is secured to a shaft 155 that is journaled in a bearing block 157. The bearing blocks 157 are attached to the underside of the common plate 135 by conventional fasteners, not shown. The shafts 155 extend through the common plate. To the upper end of each shaft is fixed a cam 159. Accordingly, actuation of the second fluid cylinder 109 causes the reciprocating racks 145 to oscillate the gears 147 and 153 and the cams 159. With the design illustrated, the two cams oscillate in opposite directions. 
     CUTTERHEAD 
     Oscillation of the cams 159 causes the cutterhead 3 to open and close the blades 5, 7, 9, and 11 over the insulated electrical conductor 13. In the preferred embodiment, cutterhead opening and closing is accomplished by the pair of symmetrically cutterhead slides 4 and 6. Each cutterhead slide comprises a yoke 161 that is fabricated with a top wall 163 and opposed outside and inside walls 165 and 167, respectively. Fastened to the interior of the inside wall 167 of each yoke 161 by screws 169 is a hardened cam wear plate 171. 
     The cams 159 are designed to simultaneously contact the respective yoke wear plates 171 and outside walls 165 with two-point contact 180° apart. Only sliding clearances are present between the cam and yoke contact points, so that there is no backlash between the cams and yokes. Further, the cams are designed with pure circular arcs that include a dwell at the beginning and end of each 180° oscillation. The cams lock the slides 4 and 6 in place during the dwell period. 
     To guide cutterhead slide reciprocation on the common plate 135, slide guide plates 173 are fastened to the edges of the common plate by fasteners 175. A key 177 acting between each guide plate 173 and the facing vertical surface of the corresponding yoke 161 prevents upward motion of the yokes relative to the common plate. To provide further guidance for cutterhead slide reciprocation, keys 178 are fixed to the common plate and mate with aligned keyways in the yokes and cam wear plates 171. The keys 177 and 178 provide three-point contact for the yokes and limit them to reciprocate in one degree of freedom. The common plate and keys 178 eliminate any problem with aligning the two cutterhead slides 4 and 6 to each other. 
     Each cutterhead slide 4 and 6 includes a tool holder assembly 179. With particular attention to FIGS. 3, 4, 8, and 9, each tool holder assembly 179 comprises a stepped support 181 that is free to slide on the respective yoke 161 in the directions of arrows 17, 29, or 19, 31. Each stepped support 181 is guided in the respective yoke by a key 183 that fits within a keyway 184 in the yoke top wall 163 and an aligned keyway 186 in the stepped support. 
     Further in accordance with the present invention, the cutting and stripping blades 5, 7, 9, and 11 are retained in the cutterhead 3 in a manner that provides exceptional accuracy and ease of blade insertion, removal, and inspection. Accurate blade mounting is accomplished by a two-piece tool holder 188 locked to each cutterhead slide 4 and 6. Each tool holder 188 defines four accurately machined surfaces of a rectangular blade holding cavity. Each two-piece tool holder comprises a tool holder base 190 and a tool holder top 192. The tool holder base 190 has a generally T-shaped cross section, as viewed in FIG. 9, with a central portion 194 and a pair of oppositely extending side legs 196. The tool holder top 192 has a top wall 198 and a pair of side walls 200. The interior surfaces 202 of the side walls 200 are accurately machined and are spaced apart to snugly fit over the tool holder base central portion 194. The upper surface 204 of the tool holder base central portion 194 and the interior surface 206 of the top wall 198 of the tool holder top 192 are also accurately machined. The tool holder top and tool holder base are joined by screws, not illustrated, extending through the tool holder base legs 196 and into the tool holder top side walls 200. Consequently, the surfaces 202, 204, and 206 define an accurate rectangular cavity for holding the cutting and stripping blades and also the spacers 212 that are used to set the blades for the proper trimming and strip length L (FIG. 1b) for the particular insulated electrical conductor 13 being processed. Cap screws 214 may be employed to rigidly clamp the blades and spacers 212 in the tool holder 188. 
     To lock the two-piece tool holders 188 to the respective cutterhead slides 4 and 6, each tool holder assembly 179 further comprises a latch 208 and a knob 210 joined to a threaded rod 213. The rod 213 passes with clearance through a hole in the latch 208 and is threaded into a latch pin 215 received in a hole in the stepped support 181. The stepped support is cut out at 216 in line with and behind the rod 213. The latch is formed with a generally V-shaped groove 217 that overlies and mates with a complementary sloped surface 219 on the top wall 198 of the tool holder top 192. The latch has a ridge 197 that bears on the top of the stepped support. In that manner, tightening or loosening the knob 210 permits easy and convenient locking or unlocking of the tool holder 188 to the stepped support and tool holder assembly. 
     It is a feature of the present invention that the cutting and stripping blades 5, 7, 9, and 11 and the spacers 212 are readily viewable and accessible by the machine operator. Those results are obtained by the sloped surface 219 of the tool holder top 192, which results in a narrower rectangular cavity at the top of the tool holder 188 than at the bottom. At the same time, the length of the top surface 204 of the tool holder base central portion 194 is substantially increased over the corresponding lengths on prior wire processing machines. The long length of the tool holder base top surface 204 assures accurate blade positioning and guiding when setting up the tooling and operating the machine 37. Further, the tool holder base 190 is machined with a keyway 218 that fits over the key 183 received in the yoke 161. The key 183 is thus common to the yoke, stepped support 181, and tool holder 188. That design assures accurate alignment of the tool holders on the respective yokes. 
     To set the tool holder assembly 179 relative to the respective yokes 161, a tool holder adjustment system 229 is provided on each cutterhead slide 4 and 6. In the embodiment illustrated, each tool holder adjustment system 229 comprises a nut 185 fastened to the back side of the stepped support 181. Threadingly received in the nut 185 is one end of an adjustment screw 187. The second end of the adjustment screw 187 is received through a support block 189. The support block 189 is fastened to the top wall 163 of the yoke 161 by screws 191. The support block is captured between a knob 193 and a collar 195. Accordingly, rotating the knob 193 causes the stepped support 181 to slide on the yoke 161 along the key 183. The screw 187 of the adjustment mechanism allows infinite adjustment resolution of the blades 5, 7, 9, and 11 toward and away from the insulated electrical conductor 13. 
     To limit the force that can be applied to the cutting and stripping blades 5, 7, 9, and 11 at initial setup, the adjustment screw 187 is designed as a torque screw. In the illustrated construction, force limitation is provided by a detent comprised of a spring-loaded ball 201 inserted into a transverse hole in a head 203 of the adjustment screw 187. The ball 201 engages a longitudinally extending groove 205 in the inner diameter of the knob 193. The adjustment screw head 203 may be retained in the knob by snap rings 207. Set screw 209 enables variable compression to be set on the spring 211. The knob 193 will slip on the screw head 203 when a predetermined torque is applied to the knob. In that manner, blade accuracy is not a function of machine operator strength, and the possibility of jamming the blades by overtightening the adjustment mechanism 229 is eliminated. 
     To assure that the tool holder assemblies 179 remain in facing contact with the respective yoke top walls 163 at all times, guide screws 221 are employed between the stepped supports 181 and the yokes 161. Preferably, two guide screws 221 are used with each stepped support. Each guide screw has a threaded end 222 received in corresponding threaded holes in the yoke. A guide portion 223 fits within appropriate slots in the stepped support. A flange 225 is located on the guide portion 223 to snugly restrain the stepped support against the yoke. For ease of assembly, the guide screws may have square heads 227. 
     The cutterhead 3 also includes a locking plate 231 and associated knob 233 on each cutterhead slide 4 and 6. The locking plate 231 is fastened to the side of the stepped support 181 with screws 235. A threaded rod passes through a slot 237 in the plate 231 and engages threads in the yoke 161. Washers are placed between the knob 233 and the plate 231. The knob 233 is turned to loosen the plate from the yoke when the adjustment mechanism 229 is actuated to position the tool holder assembly 179 on the yoke. When the tool holder assembly is at the desired location, the knob 233 is turned to draw the clamp plate firmly against the yoke and thereby assist in holding the tool holder assembly in place. 
     To eliminate malfunctions of the wire stripping machine 37 due to scrap insulation slugs 25 (FIG. 1d) being caught in the cutoff and stripping blades 5, 7, 9, and 11, the present invention includes a knockout assembly 239. The knockout assembly 239 comprises a vertical bar 241 attached to the back of the common plate 135 by conventional fasteners, not shown. A rod 243 is slidable horizontally in the bar 241 and may be locked in any desired position by a screw and nut arrangement 245. Joined to the front end of the rod 243 is a thin inverted U-shaped plate 247. Knockout legs 33 of the U-shaped plate 247 are positioned between the cutoff blades 5 and 7 and the stripping blades 9 and 11, with the knockout legs straddling the insulated electrical conductor 13. 
     OPERATION 
     The wire processing machine 37 of the present invention may be used as a stand alone unit, or it may be mounted on a conveyor type automatic wire cutting and stripping machine. In either case, the bottom base 45 is mounted to the appropriate frame member 39 with the machine longitudinal centerline 251 aligned vertically with the insulated electrical conductor 13 to be processed. 
     The knob 210 and threaded rod 213 of each cutterhead slide 4 and 6 is loosened in the respective latch pins 215. The rod 213 and latch 208 are swung backwardly, with the rod entering the cutout 216 in the stepped support 181. The tool holders 188 are removed from the cutterhead 3 for insertion of the appropriate cutoff and stripping blades 5, 7, 9, and 11 for the particular insulated electrical conductor 13. The distance L between the operative surfaces of the blades of each pair is set by means of the spacers 212 to define the length L of the insulation slug 25 (FIG. 1b). The blades and spacers are tightly clamped in the tool holders with the screws 214. The machined surfaces 202, 204, and 206 of the tool holders 188 assure accurate blade and spacer location, and the long bearing length of the surface 204 provides rigidity to the blades. The tool holders 188 are placed back into the respective tool holder assemblies 179. The latches 208 and rods 213 are swung upwardly out of cutout 216. The knobs 210 are tightened to rigidly lock the tool holders and blades to the cutterhead 3. 
     The cutterhead tool holder adjustment systems 229 are set to properly position the cutoff and stripping blades 5, 7, 9, and 11 at the closed position when processing the insulated electrical conductor 13. For that purpose, the clamp plate knob 233 on each cutterhead slide 4 and 6 is loosened. The knobs 193 are selectively rotated to move the respective tool holder assemblies 179 for the required distance and in the proper direction 17, 29 or 19, 31. With the tool holder assemblies in the proper positions, the knobs 233 are tightened to clamp the tool holder assemblies to the respective yokes 161. 
     Returning to FIGS. 2, 5, and 6, the position of the base plate assembly 43 is set in relation to the insulated electrical conductor 13 for proper insulation stripping strokes. Base plate assembly setting is accomplished by adjustment mechanism 87. The screws 77 are loosened, and the knob 89 is turned to set the end of the stripping stroke in the direction of arrow 15. At the end of the stroke in the direction of arrow 15, the block 83 abuts the stop 79, and the clearance C illustrated is taken up. 
     The knockout assembly 239 is adjusted by means of the screw and nut arrangement 245 to locate the U-shaped plate 247 between the cutoff blades 5 and 7 and the stripping blades 9 and 11. See FIGS. 4 and 8. The various knockout assembly components are so dimensioned that the knockout legs 33 of the U-shaped plate straddle the insulated electrical conductor 13 being cut and stripped by the blades. 
     The cylinders 57 and 109, FIG. 2, are actuated by suitable controls in a four-step sequence. Cylinder 57 is actuated to move the base plate assembly 43 on the bottom base assembly 41 in the direction of arrow 15. As the stop block 83 approaches the stop 79, the decelerators 73 contact the stop 79 to smoothly cushion the base plate assembly to a gradual stop. The decelerators eliminate the slamming of the stripping motion components into positive stops or shock pads that is characteristic of prior wire processing machines. 
     With the base plate assembly 43 at the end of the stripping stroke in the direction of arrow 15, the cylinder 109 is actuated to extend the piston rod 111. Consequently, the slider 115 and racks 145 rotate the gears 147 and 153 and the cams 159 in first opposite directions 252, FIG. 7. The rotating cams impart translation to the respective cutterhead slides 4 and 6 to close the blades 5, 7, 9, and 11 in the directions of arrows 17 and 19, FIGS. 3 and 4. Since the cam contours are designed with a dwell at the beginning and end of each 180° rotation, the cams fully close and accurately hold the blade positions while the rack and gears continue to rotate the cams to the ends of their 180° rotations. The extra rack travel allows the decelerators 127 to contact the roller supports 142 to smoothly snub the slider, racks, and cutterhead 3 to a gradual stop. The result is the ability of the electrical conductor processing machine 37 to exert maximum cutter force on the wire 13 while minimizing cycle time and vibrations. 
     With the cutterhead 3 closed, the cylinder 57, FIG. 2, is actuated to translate the base plate assembly 43 in the direction of arrow 23 to strip a slug of insulation 25 (FIG. 1d) from the insulated electrical conductor 13. The knockout assembly 239 prevents the stripped insulation slug from going anywhere but downwardly. Therefore, the insulation slug is removed from the processing station 1, and it can not impair the cutoff and stripping cycle of subsequent electrical conductors. 
     With the base plate assembly 43 in the fully stripped position in the direction of arrow 23, the cylinder 109 is actuated to open the cutterhead 3. The piston rod 111 retracts into the cylinder 109, thereby rotating the cams 159 in second opposite directions 254 to translate the slides 4 and 6 away from each other in the directions of arrows 29 and 31, FIGS. 3, 4, and 7. At the end of the cutterhead opening cycle, the decelerators 129 coact with the rack front shock support 113 to cushion the cutterhead to a smooth stop. The wire processing cycle is complete. A fresh length or appendage of electrical conductor 13 is then indexed to the station 1, and the cycle is repeated. See FIG. 1. 
     The blade adjustment and shock absorbing features of the wire processing machine of the present invention enable high speed precision processing of electrical conductors 13 having a wide range of conductor gauges and insulation wall thicknesses. Further, the versatility of the machine permits quick and accurate resetting to suit different electrical conductors without having to reposition the entire machine. 
     A feedback transducer can be employed in accordance with the disclosure in U.S. patent application Ser. No. 325,435 incorporated by reference. The transducer allows the generation of positional information in the form of electronic pulses. This electronic information can then be relayed to a computer, control, or an ELECTRONIC DISPLAY such as the invention of Ser. No. 325,435. 
     Thus, it is apparent that there has been provided, in accordance with the invention, a wire processing machine that fully satisfies the aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.