US3158185A

US3158185A - Apparatus for cutting a piano keyboard blank

Info

Publication number: US3158185A
Application number: US192594A
Authority: US
Inventors: Clifford W Andersen
Original assignee: Wurlitzer Co
Current assignee: Wurlitzer Co
Priority date: 1962-05-04
Filing date: 1962-05-04
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24

Description

Nov. 24, 1964 c. w. ANDERSEN 3,158,185

APPARATUS FOR CUTTING A PIANO KEYBOARD BLANK Filed May 4, 1962 6 Sheets-Sheet l A INVENTOR.

Nov. 24, 1964 c. w. ANDERSEN APPARATUS FOR CUTTING A PIANO KEYBOARD BLANK 6 Sheets-Sheet 2 Filed May 4, 1962 INVENTOK lif/Ord Mdrzaerszrz wag/21AM JJ: 01 54v,

Nov. 24, 1964 c. w. ANDERSEN 3,153,185

APPARATUS FOR CUTTING A PIANO KEYBOARD BLANK Filed May 4, 1962 6 Sheets-Sheet 3 INVEN TOR.

Nov. 24, 1964 c. w. AN DERSEN 3,158,135

APPARATUS FOR CUTTING A PIANO KEYBOARD BLANK Filed May 4, 1962 6 Sheets-Sheet 4 lNVENTOR.

(Ja /0rd (l1 Qaaer sem BY 0AM, mg zflmaw Nov. 24, 1964 c. w. ANDERSEN 3,158,185

APPARATUS FOR CUTTING A PIANO KEYBOARD BLANK Filed May 4, 1962 6 Sheets-Sheet 6 CLUTCH 1 I 54W can/770a CLUTCH TRHMSPORT 74 sou-M010 M0100 6) F' l i V i I 66 l l 4 6 J- 1 i 1 l I I I aw I IA I. III

z95- "WM IN VENTOR.

3,158,185 APPARATUS FQR CUTTING A PIANO EYEQARD BLANK liliord W. Andersen, De Kalb, iiL, assignor to The Wurlitzer Company, Chicago, ill, a corporation of @ie Filed May 4, 1962, Ser. No. 1%,594 8 Qlairns. {(Il. 14 -2} This invention relates generally to the manufacture of pianos and analogous musical instruments and more particularly to the manufacture of operating levers or keys for such instruments.

In accordance with conventional practice, the keyboard of a piano is made up of an appropriate number of key levers, each of which comprises a wooden body faced with a decorative and wear-resistant cover. The wooden key bodies are cut from a single board corresponding to the general form of the finished keyboard; and in the past, the cutting operation has been performed using a bandsaw and manipulation of the keyboard blank by hand to make the various cuts. Extraordinary care and skill has been required in aligning the keyboard blank relative to the saw blade, in advancing the blank to make the cut and in withdrawing the blank to extract the saw blade from the cut. As a consequence, rather substantial amounts of expensive skilled labor have heretofore been devoted to keyboard production; and moreover, the slight variations inherent in the manually cut key levers have precluded any acceptable degree of interchangeability of corresponding keys from different keyboard blanks. Replacing a broken or damaged key lever has therefore required the tailoring of a substitute, rather than obtaining a completely satisfactory replacement from stock.

Therefore, an important obiect of the present invention is to provide apparatus for making accurate and reproduceable cuts in a keyboard blank.

Another object of the invention is to provide apparatus for producing interchangeable key levers for pianos and analogous musical instruments.

A more general object of the invention is to provide a new and improved apparatus for cutting a keyboard blank in the production of keys for pianos and analogous musical instruments.

A furth r object of the invention is to provide apparatus which automatically performs a cycle of cutting operations on a keyboard blank.

A still further object of the invention is to provide apparatus for making deflected cuts in a keyboard blank.

And a still further object of'the invention is to provide apparatus which is arranged for selectively varying the angle of deflection in such a cut.

A further object of the invention is to provide apparatus for-performing a cutting operation on a keyboard blank in an economical manner.

These and other objects and features of the invention will become more apparent upon a reading of the following descriptions.

Apparatus in accord with the invention includes a cutting unit including an actively operating saw blade; 21 carrier unit for supporting and holding a keyboard blank generally in aplane perpendicular to the cutting edgeot the saw blade; arrangements for incurring relative converging, rotative and separating movements of the carrier unit and the cutting unit whereby to urge the saw blade into edgewise cutting relationship with the keyboard blank and thereafter to withdraw the blade from the blank; an index ingunit for incurring relative stepwise transporting'mova merits between the cutting unit and a portion of the carrier unit along a path in the above-mentioned plane and generally perpendicular to the path of the converging andsep- United States Patent 3,158,185 Patented Nov. 24, 1964' ice arating movements; and position responsive arrangements for controlling the operation of the indexing unit and the means for incurring the relative converging, rotative and separating movements of the carrier unit and the cutting unit.

in order that the principles of the invention may be more readily understood, a single embodiment thereof is shown in the accompanying drawings wherein:

FIG. 1 is a top plan view of a keyboard blank readied for making the rear cuts in the production of individual key levers, the cuts which have been made on the front edge of the keyboard blank being shown in solid outline and the cuts which are to be made in the rear portion of the keyboard blank being shown in broken outline;

FIG. 2 is a perspective view of a portion of the apparatus of the invention shown in operative position for making one of the rear cuts in the keyboard blank of FIG. 1;

FIG. 3 is a side elevational view of the apparatus of the invention;

FIG. 4 is an enlarged plan view taken along the line 44 of PEG. 3;

FIG. 5 is a plan view taken along the line 55 of FIG. 3;

FIG. 6 is an enlarged, fragmentary radial, cross-sectional View taken along the line 6-6 of FIG. 5 and showing a portion or" the means for varying the deflection angle of the cuts to be made in the keyboard blank;

FIG. 7 is a schematic plan view showing the keyboard blank and the saw blade in their position of extreme separation;

PEG. 8 is a view similar to the showing of FIG. 7 but illustrating the keyboard blank having been advanced against the saw blade to the point of deflection in the cut;

FIG. 9 is a similar view showing the saw blade being advanced to make the second portion of the cut;

FIG. 10 is an enlarged plan view of the arrangement which is employed in selecting the angle of deflection to be made in the cut;

FIG. 11 is a schematic circuit diagram showing means for operating and controlling the lower turret drive motor;

FIG. 12 is a schematic circuit diagram showing the means for operating and controlling the upper turret drive motor;

FIG. 13 is a schematic circuit diagram showing the means for operating and controlling'the saw transport motor;

PKG. 14 is a side elevational 14-14 of FIG. 10; and

FIG. 15 is an enlarged perspective View of the positioning plate of FIG. 3 and the limit switches which are mounted on it.

Referring now in detail to the drawings, specifically to FIG. 1, a keyboard blank will be seen indicated generally by the numeral 26. The blank comprises a number of narrow wooden strips which are secured together at their lateral edges by means of a suitable adhesive, the individual strips being cut from a suitable wood such as maple in Widths varying from approximately one and one-half to approidmately three inches or more. The grain'of the wood advantageously runs along the length of each strip.

view taken along the line Having the grain pattern so arranged in the keyboard f blank 20 results in the production ofstrong and highly serviceable key bodies.

After the basic board has been assembled from the component wooden strips, it is planed and shaped to semifinished form; and thereafter it is drilled and routed to make the holes for the front railpins and balance rail 1 pins. The balanced rail pin holes fo'rthe natural note key levers are indicated by the numeral 22, and the balance.

rail pin holes for the sharp note key levers are indicated generally bythe numeral 24. Next, the keyboard blank 20 angle to generate the deflection in the cut.

is lanced or slit at the front end of the sharp note key levers to produce the cuts indicated by the numeral 26 which cuts serve to facilitate removal of the sharp note keys upon completion of subsequent operations. Advantageously, identification numbers are stamped or debossed simultaneously with the lancing; and in addition, the holes 22 and 24 may be countersunk to permit ready application of felt linings to these holes in a subsequent operation.

After the holes 22 and 24 have been lined with felt, key covers or facings 28 may be applied to the natural note key levers, the inner end limits of the facings 28 being indicated by a line 29. Thereafter, comparatively shallow cuts 36 are made in the front edge of the keyboard blank to separate the front portions of the several natural note key levers. These front cuts 30 are shown penetrating the keyboard blank uniformly to a line indicated by the numeral 32; however, it is to be realized that deeper cuts may be made between certain of the natural note key levers, as for example, between the B note and C note key levers, if desired.

While it is acceptable to direct the front cuts 30 into intersection with the lance cuts 26, the subsequently formed back cuts desirably stop short of actual intersection with the lance cuts 26 and with the front cuts 30. Such a procedure leaves narrow tongues whichhold the keyboard blank 20 in one piece whereby to avoid handling of large numbers of loose parts at the back cutting machine.

The various back cuts which are to be made in the keyboard blank 20 are indicated in FIG. 1 by the numeral 34; and each of the cuts 34 includes a front portion 36 and a rear portion 38, the

portions

36 and 38 being angulated relative to each other whereby to define points of deflection 48 in the cuts 34.

The keyboard which is produced from the blank 20 is advantageously provided with notches or spaces opening from the back edge thereof to accommodate the brackets by which the piano actions are mounted in the piano structure. These spaces are provided by making the deflected cuts 34 and by varying the angle of deflection to develop two tapered recesses 42 and 44 which are employed in passing the action brackets. As will be recognized, segments 46 and 48 are cut from the rear edge of blank 2i)v in forming the recesses 42 and 44 respectively. Moreover, three groups of basically similar key bodies result from varying the angle of deflection established in the cuts 34; and as will be recognized, the segments 46 and 48 are automatically extracted from the keyboard blank 20when the saw blade used in making the cuts 34 is backed out of the secondof the two cuts that define each of the recesses 4-2 and 44.

In compliance with the present invention, the actual incising of keyboard blank 20 to form the cuts 34 is performed by an actively operating saw blade; and the keyboard blank is supported generally in a plane perpendicular to the cutting edge of the saw blade. In order to develop the desired path of cutting, relative converging, rotative and separating movements are caused to occur between the actively operating saw blade and the keyboard blank. Specifically, the keyboard blank is first advanced into cutting engagement with the saw blade; and after the saw blade has traversed a first portion of the cutting path, corresponding to the portion 38 of a cut 34, the keyboard blank is rotated through an appropriate Thereupon, the saw blade is advanced into the keyboard blank to traverse a second portion of the cutting path in order to complete the desired cut. The reverse sequence of operations occurs in retracting the saw blade from the cut. It is recognized that other combinations of converging, rotative and separating movements can be arranged to perform the desired cutting result.

The general arrangement of the invention is broadly indicated in FIG. 2 where the keyboard blank 20 is shown supported and held by a carrier unit 58' and where an actively operating saw blade 52 is shown incorporated in a cutting unit 54. In the illustrated embodiment, the saw blade 52 is shown as a saber saw blade; but it is to be realized that the saw blade 52 may be equally well selected to be a bandsaw blade. In either event, it is to be understood that the saw blade 52 is relatively narrow in order that it may be turned relative to a keyboard blank into which it has been incisingly directed whereby to facilitate its forming a deflected cut in the blank.

Turning to FIG. 3 for a more detailed description of the apparatus of the invention, it will be recalled that the second portion of each of the cuts 34, i.e. the portion 36, is to be formed by advancing the saw blade 52 through the keyboard blank 20. For this purpose, the cutting unit 54 is fashioned to include a base 56, a carrier member or superstructure 58 and a drive arrangement 60 acting between the base and the superstructure. The base 56 includes a column 62 which is anchored to the floor, additionally including a platform 64 cantilevered from the column 62. The superstructure 58, on the other hand, houses a drive motor 65 for the saw blade 52 and includes a guide plate 68 for controlling the tip of the saw blade. The superstructure 58 additionally incorporates a foot 70 which is slidably connected to the cantilevered platform 64 by means of a dove-tail slide 72.

Advantageously, bearing strips act between abutting surfaces of foot 70 and platform 64 to reduce friction and facilitate the horizontally advancing and retracting movements of the saw blade.

The drive arrangement 60 includes a motor 74 which is mounted within the superstructure 58 and a clutch 76 which operates to transmit motive power from motor 70 to a pinion gear 78, clutch 7 6 being controlled by a solenoid 88 in a manner to be described more fully hereinafter with reference to FIG. 13. The pinion gear 78 meshes with a spur gear 82 that is connected, in turn to a spur gear 84 situated externally of the superstructure 58. Spur gear 84 drivingly meshes with a rack 86 which is mounted to the platform 64 in parallel alignment with the dove-tail slide 72.

The carrier unit 50, on the other hand, includes a base 88 which is supported on the floor, a lower turret or carrier member 90 which is slidably mounted on the base 88, and an upper turret or carrier member 92 which is rotatably mounted on the lower turret 80. As has been described, the initial portion of each of the cuts 34, i.e. the portion 38, is made by advancing the keyboard blank 20 into the stationary but actively operating saw blade; and this advancing movement is implemented by the slidable mounting of lower turret 90 relative to the base 88. In compliance with the illustrated embodiment,

a dove-tail slide 94 is employed in connecting lower turret 6 to the base 88; and advantageously, bearing strips are provided at the abutting surfaces of the base and the turret for reducing friction. In further compliance with the illustrated embodiment, the axis of slide 94 is arranged in parallel alignment with the slide 72 of the cutting unit. 7

In order to provide the desired advancing and retracting'movements, a drive arrangement indicated generally by the numeral 96 is arranged to act between the turret 98 and the base 88. Specifically, the drive arrangement 96 includes a motor 98 which is coupled to a pinion gear 169 through a clutch 182. The clutch 102 is controlled by a solenoid 184, and the pinion gear is meshed with a spur gear 166 that is connected to a second spur gear 108 exposed externally of the turret 90. The spur gear 188 meshes with a rack 11% which is fixed to the side ofbase 88, rack 110 providing the reaction necessary for converting the power of motor 98 to translative motions of the turret 90. Control of the operation of the motor98 will be described more fully hereinafter with regard to FIG. 11.

With reference for the moment to FIG. 5, it has sometimes, proved desirable to provide tractive elements on both sides of lower turret 96. Under such circumstances, spur gear 168 is afiixed to a shaft 112 which extends through the turret to have a spur gear 114 secured to its opposite end and exposed on the opposite side of the turret. Spur gear 114 meshes with a rack 116 which is afiixed to the base 8%.

The deflection formed in each of the cuts 34 by angulating the

portions

36 and 38 thereof is developed by rotating the keyboard blank 24 when saw blade 52 has reached the intersection of the

respective portions

36 and 38. In order to achieve this rotation of the keyboard blank 20, upper turret 92 is rotatably mounted on the lower turret 9% Continuing with reference to FIG. 3, the turrets 9'19 and 92 are seen fashioned with opposed, circular grooves 115 and 12% respectively, these grooves advantageously taking V-shaped cross-section. A suitable number of ball bearings 12-2 are situated between the grooves 118 and 1213 to implement the rotatable mounting of upper turret 92. A post 124 upstands from turret S ll slidably to enter a cooperatively shaped bore in turret 92, post 124 bein concentric with the circular grooves 118 and 12b to act as a centering element for the rotations of turret 92. A drive arrangement indicated generally by the numeral 12K is directed to act between the turrets fill and 92; and drive arrangement 126, being similar to drive arrangements so and 95, is comprised of a motor 123, a clutch 131i and a solenoid 132 for use in controlling the clutch. Motor 128 and solenoid 132 are affixed to turret 91 by a bracket 1%, and solenoid 132 includes an armature 13-6 which is arranged to pass slidably through hollow output shaft 133 of motor 123. Clutch 130 includes a plate 149 which is fixed to armature 136, clutch 13h additionally including a plate 142 fixed to the output shaft 133 and biased apart from plate 1 h) by a spring, not shown. Thus, when solenoid 132 is energized to attract armature the

plates

140 and 142 are drawn into engagement in order that motor 123 may drive a spurgear 144 which is ailixed to the clutch plate 1 The spur gear lid meshes with a segment gear 146 which is afiixed to the turret 92; and thus, motor 128 is able to cause rotations of the turret 92. The control of motor 123 will be described more fully hereinafter with reference to FIG. 12.

In order to support the keyboard blank 20 at a suitable distzmce above the turret 92, a post 148 is affixed to the turret 92, the vertical axis of post 148 being aligned with the axis of rotation of the turret. This axis of ro tation is indicated by the numeral 156. In addition, a platform 152 is affixed to the top end of post 148. The keyboard blank 20 is specifically supported on platform 152 by means of a plate member 154 and clamping arrangements 156. The plate member 154 is connected to platform 152 by a dove-tail slide 153, slide 158 implementing transporting movements of the keyboard blank 2'8 in a path which is generally perpendicular to the paths of movement of superstructure 58 and lower turret 90. The dove-tail slide 153 includes bearing strips 160 which act between abutting surfaces of platform 152 and plate member 154 to reduce friction.

With reference to FIGS. 2 and '3, the clamping arrangements 156 are seen to be comprised of an arm 162 fixed to the plate member 154 and an arm member 164 coupled to the fixed arm 162 by a rod 166. The clamping arrangements 156 also include bolts 163 and a strip 173 which are employed in grippingthe front edge of keyboard blank 29.

With reference to F263. 3 and 4, the apparatus of the invention is provided with an indexing unit 172 for incurring relative stepwise transporting movements between the keyboard blank 2ll and the cutting means defined by the saw blade 52. As is best shown in FIG. 4,-

the indexing unit 172 includes a housing 174 which encloses a drive motor 176. Motor 175 is rigidly mounted to platform 152 and has its output shaft connected to a 5 drive disc 178. A link 18% is swingably mountedto disc 178 by a pivot pin 182 that is disposed eccentrically on the disk. Link 1819 is coupled to a ratchet wheel 1% by a link 186 that is pivotally connected to both the link 180 and the ratchet wheel. A pawl 1&8 is disposed in operative relationship with the ratchet wheel 184 by be ing mounted on a-pivot pin 1% by which the

links

180 and 186 are interconnected. To complete the mechanical connection between motor 176 and plate member 154, the ratchet wheel 184 isfiXed to a'spur gear 192; and spur gear 192 is arranged to mesh with a rack 194 that is fixed to the edge of the plate member 154. It is to be recognized that a rotation of. drive plate 178 through one full circle of revolution may be caused by the operation of motor 176 in order to transport keyboard blank 2% through one step defined by the ratchet, the pawl, the spur gear and the rack. Such a step is arranged to correspond with the lateral spacing between the individual cuts 34 which are to be made in the keyboard blank. v

In compliance with the invention, position responsive arrangements are employed to control the motors 74, fit, 128 and 176 whereby to direct the desired movements of superstructure 58, turret 9d, turret 92 and plate member 154 respectively. These position responsive arrangements specifically take the form of limit switches. Motors .74, 93, 128 and 176 are cooperatively selected to be electric motors; and in order to incur the desired reversible movements, the several motors are particularly selected to be DC. motors. Of course, the desired reversing of the direction of operation of such a motor maybe achieved by reversing the polarity in either the field or the armature winding of such a motor.

Turning to FIG. 11, the lower turret drive motor 93 is seen energized from a suitable DC. source 2191?; and selection of the direction of rotation is made by means of a double pole, double throw reversing switch 202, switch 22 being controlled by individual circuits containing, respectively, a normally open limit switch 2494 and a normally open limit switch 2%, switch 206 being shown operated into closed condition. Switch 2194 selectively energizes a solenoid 293, and switch 2% energizes a solenoid 21b, solenoids 2&8 and 210 operating the reversing switch 2'92. As is seen in FIG. 3, switches 2M and 21% sense the presence of the lower turret 9d at the opposite ends of its path of travel.

Returning to FIG. 11, the clutch control solenoid 1134 is seen operated by a normallyopen limit switch 212 which is connected in series circuit with a normally closed limit switch 214*. In addition, the solenoid 1% is operated by a normally open limit switch 216 which is connected in series circuit with a normally closed limit switch 213, the circuit comprising switches 216 and 213 being paralleled with the circuit comprising switches 212 and 214-. Switches 212-218 specifically operate the solenoid 1&4 through a relay 22% With reference to FIG. 4, limit switch 212 is seen arranged to sense the normal or quiescent position of link 1%, switch 212 being held closed by the presence'of link 1819 inthis position and being released to its normally open state upon actuation of the link to index the plate member 154. With reference to FIG. 3, switches and 218 are seen arranged to sense the presence of the turret it. at its opposite positions of extreme travel whereas switch 216 is seen carried by a switch-positioning plate 222 which is rotatably mounted to turret 92, switch 216 being arran ed to sense an angular position of turret 92 relative to an abutment plate 224 which extends radially from drive arrangement 126 toward the turret 92. A more complete description of positioning plate 222 and its functions will be given hereinafter.

Considering FIG. 12, the upper turret drive motor 128 is seenenergized from a suitable DC. source 226, its

polarity and therefore its direction of rotation being se throw reversing switch lected by a double polo, double 228. The particular orientation oi switch 228 is determined by individual circuits containing normally open limit switches 23% and 232 respectively, switch 232 being shown operated into closed condition. The circuit containing switch 230 also includes a solenoid 234 whereas the circuit containing switch 232 additionally incorporates a solenoid 236. With reference to FIG. 3, the switch 230 is seen carried by positioning plate 222 in approximate alignment with switch 216. The switch 232 is also carried by positioning plate 222 spaced angularly apart from the switch 230, as shown in FIG. 15.

With renewed reference to FIG. 12, clutch control solenoid 132 is operated by a normally open limit switch 238 which is connected in electrical series circuit with a normally closed limit switch 240. Solenoid 132 is additionally operated by a normally open switch 242 which is connected in series with a normally closed limit switch 244, the

circuit comprising switches

242 and 244 being connected in parallel with the

circuit comprising switches

238 and 240. Switches 238-244 operate solenoid 132 through a relay 246.

Again with reference to FIG. 3, switch 233 is seen aligned with

switches

204 and 214 to sense the presence of turret 90 in its position closest to the cutting unit 54. Moreover, switch 242 is seen arranged on base 56 of the cutting unit to sense the presence of superstructure 58 in its position of extreme retraction from the keyboard blank 20. Switch 244 is mounted on positioning plate 222 in general alignmentwith switches 216 and 236, whereas switch 240 is mounted on the positioning plate spaced angularly apart from switch 244 in approximate alignment with switch 232. Thus, switches 244 and 246 sense the presence of turret 92 in its two angularly extreme positions of rotation.

As is shown in FIG. 13, the saw transport motor 74 is energized from a suitable D.C. source 243, its polarity and therefore its direction of rotation being selected by a double pole, double throw reversing switch 250. The orientation of reversing switch 256 is determined by individual circuits incorporating, respectively, normally

open limit switches

252 and 254, switch 254 being shown operated into closed condition. The circuit containing limit switch 252 also incorporates a solenoid 256; and similarly, the circuit incorporating switch 254 embodies a solenoid 2S8,

solenoids

256 and 258 operating the switch 250. With reference to FIG. 3, switch 252 will be seen mounted on superstructure 58 to sense the presence of keyboard blank 20 in the extreme position of convergence between carrier unit 50 and cutting unit 54. Switch 254, on the other hand, is mounted on base 56 in alignment with switch 242 to sense the presence of superstructure 58 in its position of extreme retraction.

Returning to FIG. 13, clutch control solenoid 80 is seen operated by means of a normally open limit switch 266 which is disposed in series electrical circuit with a normally closed limit switch 262. Clutch control solenoid 80 is additionally operated by means of a normally closed limit switch 264 which is disposed in parallel with the circuit comprising switches 269 and 262. Switches 269- 264 operate the solenoid 8th through a relay 266.

Switch 262 is specifically arranged to be a delay switch; and accordingly, the movable contact of the switch is connected to air dashpot 268 and to a compression spring 270, dashpot 268 and spring 276 being additionally connected to a structural wall 272. So arranged, switch 262 is held open for a short period of time by air dashpot 268 once its contacts have been opened, dashpot 268 resisting the force of spring 270 for a selected period of time in which the contacts of switch 262 remain open in the absence of a member abutting the movable contact thereof. I

Turning toFIG. 3, switch 262 is seen mounted in alignment with switch 252 on the superstructure 58 in order to sense the presence of keyboard blank 20 in the position of extreme convergence of carrier unit 50 and cutting 8 unit 54. In addition, switch 264 is seen disposed in alignment with

switches

242 and 254 on base 56 whereby to sense the presence of superstructure 53 in its position of extreme retraction. Switch 260 is mounted on the positioning plate 222 in approximate alignment with

switches

232 and 240.

In somewhat similar manner, the drive motor 176 for indexing unit 172 is energized through a limit switch 274 shown in FIG. 3 as being arranged for sensing the presence of lower turret in its position of extreme retraction. Moreover, a limit switch 276, shown in FIG. 4, is arranged to terminate operation of drive motor 176 upon completion of a stepwise transporting movement of the plate member 154, switch 276 being specifically arranged to sense the corresponding position of link 180. Advantageously, the control circuit for drive motor 176 also includes a manual switch, not shown, for initiating operation of the apparatus.

As mentioned hereinabove, the angle of deflection which is made in the saw cuts 34 is varied periodically as the cuts are progressively made from the leading side edge to the trailing side edge of the keyboard blank 20. These alterations are made in the same angular direction in order to be cumulative; and the deflection angle, as delined by rear portions 38 of the cuts 34, passes through relative to the front portions 36 at the segment cut 46 as is indicated in FIG. 1.

The angle of deflection is varied by rotating the switch positioning plate 222 relative to the upper turret 92; and turning to a consideration of FIGS. 5 and 6, the plate 222 is mounted for relative angular movements by being secured to turret 92 using a dove-tail slide 28h, best shown in FIG. 6. The plate 222 has its outer surface fashioned with gear teeth 282 for meshing with a pinion 284. The pinion 284 is driven by a motor 286 which is coupled to the pinion by a clutch 228 that is operated by means of a control solenoid 2%. The motor 236 is desirably a DC. motor for ease in reversing, and the reversing in the direction of motor 286 is desirably controlled by a manual switch which is actuated upon completion of a full cycle of operation in preparation for the initiation of a new cycle.

Motor 286 is drivingly coupled to positioning plate 222 when it is desired to alter the angle of deflection being made in the cuts 34, and solenoid 296 is appropriately controlled to achieve this coupling by limit switches, such as the

limit switches

292 and 294 shown in FIG. 14. The

switches

292 and 294 are of the normally open type, being arranged to be closed respectively by means of cams 2% and 228. As is shown in FIG. 10, the

cams

296 and 298 are secured to the plate member 154 in coactable relationship with the

switches

292 and 294,

switches

222 and 294 being mounted to platform 152 by a bracket 3% shown in FIG. 14. The cams 2% and 298 are provided with rises of an appropriate length for determining the time period during which the corresponding limit switch is closed for energizing the clutch control solenoid and thereby operating the motor 286 to drive the plate 222. The

switches

252 and 294 are connected in electrical parallel circuit and act through a relay, not shown, in the control of solenoid 292i. Advantageously, a manual switch is also connected in parallel with the

limit switches

292 and 294 for use in resetting the apparatus to initiate a new cycle of operation. As will be recognized, additional variations in the angle of deflection may be secured by the provision of additional limit switches and cams to augment the

limit switches

292 and 294 and the cams 296 and 29S.

Having'thus described one construction of the invention, it is important now to state how the illustrated embodiment operates. The principal reference will be had to FIGS. 7-9, there being secondary reference to FIGS. 3, 4, and 11-13.

Assuming that the apparatus is in the process of cutting a keyboard blank, a number of individual cuts 34 already having been made, and assuming that the saw blade 52 is retracted and that the keyboard blank has been indexed and rotated into proper angular position for the next cut, operation will proceed as follows.

When the indexing has been completed to advance the keyboard blank one step, the link 180 will operate on

limit switches

212 and 276 to energize clutch control solenoid ltl-t and to terminate indexing of the plate member 154- respectively. Energization of clutch control solenoid 184 acts to couple lower turret drive motor 98 togear 108 causing the turret 9% to advance toward the saw blade 52 which is operated in stationary position at this point in the cycle. PEG. 7 shows the keyboard blank at the end of the indexing step and FIG. 8 shows the keyboard blank advanced against the saw blade 52 to the point of inflection 40 in the cut. It will be observed that the saw blade 52 has formed the portion 38of the cut at this juncture.

When the keyboard blank Zll has reached this position relative to the saw blade 52, the lower turret 9%} will have advanced into actuating relationship with limit switch 214 which thereupon acts to open the circuit to the lower turret clutch solenoid causing the spring biased plates to be opened by the spring force whereby to terminate the advance of the keyboard blank. At the same time the lower turret actively engages limit switch 294 to reverse the polarity of motor 98 conditioning it for subsequent retraction. In addition, the lower turret 9h actuates limit switch 23% subsequently to limit switch 214; and limit switch 238 closes a circuit to energize clutch control solenoid 132 to couple upper turret 92 and the corresponding drive motor 128 for rotation of platform 152 and thereby the keyboard blank 20. The end of the platform rotation is sensed by limit switch 24% being rotated into engagement with switch abutment 224, switch 240 opening the circuit to clutch control solenoid 132 for disconnecting drive motor 128 from spur gear 144, thus ceasing rotation of upper turret 92. At the same time, limit switch 232 is driven into actuating relationship with the abutment 224 to reverse the polarity of motor 128 conditioning it for reverse rotation. Simultaneously, switch 260 is closed by engagement with abutment 224 for completing a circuit to clutch control solenoid 84 whereby to couple saw transport motor 74 to gear 84 in order to advance saw blade 52 into the keyboard blank 2%. FIG. 9 shows the keyboard blank 28 having been rotated through its deflection angle and shows the saw blade 52 having been advanced from the inflection point 49 into the keyboard blank whereby to create the portion 35 of cut 34.

Limit switch 262 disposed on the superstructure 58 is engaged by the rear edge of the keyboard blank 29 to sense the end of the saw cut; and during the decay period of switch 262, switch 252 acts to reverse the saw trans port motor. Upon switch 252 returning to its normally closed state, motor 74 is recoupled to gear 84 in order to retract the saw blade 52. When the rear wall of superstructure 58 engages limit switch 2&4, switch 264 there upon acts to open the circuit to clutch control. solenoid 8t), disconnecting the superstructure 58 from motive power and stilling its movement. Simultaneously, limit switch 254 is actuated for reversing the polarity of motor 74; and the rear wall of superstructure 53 abuts limit switch 242 immediately after abutting switch 264-, switch 242 thereupon operating the clutch control solenoid for upper turret drive motor 128 for reversely rotating the platform .152 and the keyboard blank carried thereon.

The opposite end of the platform rotation is sensed by, limit switch 244 which is arcuately displaced from limit switch 240 on switch positioning plate 222, switch 244 acting on the solenoid 1.32 to disengage clutch 131) for ceasing the rotation.

The limit switch 216 is acted uponbyabutment plate 224- subsequent to limit switch 244-, and at this point, i

switch 216 operates to energize the circuit to solenoid 7 being interchangeable.

194, coupling the motor 98 to spur gear 108 for ret'racting the keyboard blank from engagement with saw blade 52. The end of the travel of lower turret 9%} is sensed by limit switch 218 which thereupon acts to disengage the lower turret clutch 1&2 by deenergizing solenoid 1G4. Simultaneously, switch 296 is acted upon to reverse the polarity of motor 98 to condition it for'subsequent advancing movements. At the same time limit switch 274 is caused to energize the circuit to motor 176 applying motive power to the indexing unit 172 for incremental advance of the keyboard blank.

Thus,- one cutting cycle is completed; and it is to be recognized that this cycle will be repeated to make the remaining cuts.

After the sawing operation is completed, the keyboard blank 20 is manually broken by fracturing the narrow tongues separating the back cuts 34 from the front cuts 3% and the lance cuts 26. The individual key bodies which are thus released are thereafter trimmed, the natural note key facings suitably polished and the sharp note key facings applied to the corresponding key bodies.

By use of the apparatus just described, accurate and reproducible cuts can be made in a keyboard blank, the resultant key bodies possessing the desirable property of In addition, the described apparatus automatically performs the cycle of cutting operations and performs them in an economical manner.

Therefore, the specific examples herein shown and described are to be considered as being primarily illustrative. Various changes in structure may occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

The invention is claimed as follows:

1. Apparatus to be used in forming a series of transverse defiected slots penetrating edgewise into but not completely across a keyboard blank in the production of keys for pianos and analogous musical instruments, said apparatus comprising: cutting means including a saw blade and a drive for said blade; carrier means for sup porting and manipulating a keyboard blank generally in a plane perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting said platform member on said base, first guide means for directing rotary movement of said first carrier member about an axis generally perpendicular to said plane, and second guide means for directing reciprocating movements of saidsecond carrier member in a path generally toward and away from said saw blade; drive means connected to said second carrier member for causing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting at the rear edge thereof and whereby to separate said blade and said blank after the formation of a second straight-line cut confluent with and laterally deflected from said first cut; rotary drive means connected to said first carrier member for rotating said first carrier memher and thereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second'cuts, said rotary drive reversibly rotating said first carrier member through said predeterminedangle upon completion of said second cut and upon Withdrawal of said blade to the deflection point between said cuts; drive means operatively connected to one of said cutting means and'saidcarrier means for incurring straight-line, relative converging and separating movementsthereof between the rotation and the reversible rotation of said first carrier member for urging said saw blade and said keyboard blank into cutting relationship in forming said second straight-line cut; and indexblade and a drive for said blade; carrier means ing means for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon separation of said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank.

2. Apparatus according to claim 1 and further comprising position responsive means disposed to be operatively engaged by said second carrier member for operating said indexing means when said carrier means and said cutting means are in their separated state.

3. Apparatus according to claim 1 and further comprising means for varying said predetermined angle.

4. Apparatus to be used in forming a series of transverse deflected slots penetrating edgewise into but not completely across a keyboard keys for pianos and analogous musical instruments, said apparatus comprising: cutting means including a saw I01 supporting and manipulating a keyboard blank generally in a plane perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting said platform member on said base, first guide means for directing rotary movement of said first carrier member about an axis generally perpendicular to said plane, and second guide means for directing reciprocating movements of said second carrier member in a path generally toward and away from said saw blade, said platform member including a first element fixed to one of said carrier members and a second element slidably coupled to said first element; drive means connected to said second carrier member for causing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting; at the rear edge thereof and whereby to separate said blade and said blank after the formation of a second straight-line cut confluent with and reflected from said first cut; rotary drive means connected to said first carrier member for rotating said first carrier member and thereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second cuts, said rotary drive reversibly rotating said first carrier member through said predetermined angle upon completion of said second cut and upon withdrawal of said blade to the deflection point between said cuts; drive means ooeratively connected to one of said cutting means and said carrier means for incurring straight-line, relative converging and separating movements thereof between the rotation and the reversible rotation of said first carrier member for urging said saw blade and said keyboard blank into cutting relationship in forming said second straight-line cut; and indexing means including drive means operative between said first and second elements for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon separationof said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank.

5. Apparatus to be used informing a series of transverse deflected slots penetrating edgewise into but not completely across a keyboard blank in the production of keys for pianos and analogous musical instruments, said, apparatus comprising: cutting means including a saw blade 7 and a drive for said blade; carrier means for supporting and manipulating a keyboard blank generally in a plane blank in the production of perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting aid platform member on said base,

rst guide means for directing rotary movement of said first carrier member about an axis generally perpendicular to said plane, and second guide means for directing reciprocating movements of said second carrier member in a path generally toward and away from said saw blade; drive means connected to said second carrier member for causing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting at the rear edge thereof and whereby to sepmate said blade and said blank after the formation of a second straight-line cut confluent with an deflected from said first cut; rotary drive means connected to said first carrier member for rotating said first carrier member and thereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second cuts, said rotary drive reversibly rotating said first carrier memher through said predetermined angle upon completion of said second cut and upon withdrawal of said blade to the deflection point between said cuts; drive means operatively connected to one of said cutting means and said carrier means for incurring straight-line, relative converging and separating movements thereof between the rotation and the reversible rotation of said first carrier member for urging said saw blade and said keyboard blank into cutting relationship in forming said second straight-line cut; indexing means for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon'separation of said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank; control means for operating the drive means for said second carrier member, including means responsive to the completion of a said stepwise transporting movement, means responsive to the presence of said saw blade at the juncture of said deflected cuts, means responsive to the presence of said first carrier member at one terminus of its rotation, and means responsive to the presence of said second carrier member at its position of extreme retraction from said saw blade; and control means for operating the rotary drive means for said first carrier mem ber, including means responsive to the presence of said saw blade at the juncture of said deflected cuts, means responsive to the presence of said first carrier member at said one terminus of its rotation, and means responsive to the presence of said first carrier member at the opposite terminus of its rotation.

6. Apparatus to be used in forming a series of transverse deflected slots penetrating edgewise into but not completely across a keyboard blank in the production of keys for pianos and analogous musical instruments, said apparatus comprising: cutting means including a saw blade and a drive for said blade; carrier means for supporting and manipulating a keyboard blank generally in a plane perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting said platform member on said base, first guide means for directing rotary movement of said first carrier 'member about an axis generally perpendicular to said plane, and second guide means for directing reciprocating movements of said second carrier member in a pathgenerally toward and away from said saw blade, said platform member including a first ele- I ment fixed to one of said carrier members and a secnd element slidably coupled to said first element; drive means connected to said second carrier member for caus ing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting at the rear edge thereof and whereby to separate said blade and said blank after the formation of a second straight-line cut confluent with and deflected from said first cut; rotary means connected to said first carrier member for rotating said first carrier member and tiereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second cuts, said rotary drive reversibly rotating said first carrier member through said predetermined angle upon completion of said second cut and upon withdrawal of said blade to the deflection point between said cuts; drive means operatively connected to one of said cutting means and said carrier means for incurring straight-line, relative converging and separating movements thereof between the rotation and the reversible rotation of said first carrier member for urging said saw blade and said keyboard blank into cutting relationship in forming said second straight-line cut; indexing me ans including drive means operative between said first and second elements for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon separation of said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank; control means for operating the drive means for said second carrier member, including means responsive to the completion of a said stepwise transporting movement, means responsive to the presence of said saw blade at the juncture of said deflected cuts, means responsive to the presence of said first carrier member at one terminus of its rotation, and means responsive to the presence of said second carrier member at its position of eX- treme retraction from said saw blade; control means for operating the rotary drive means for said first carrier member, including means responsive to the presence of said saw blade at the juncture of said deflected cuts, means responsive to the presence of said first carrier member at said one terminus of its rotation, and means responsive to the presence of said first carrier member at the opposite terminus of its rotation; and control means for operating the drive means of said indexing means, including means responsive to said second carrier member at its position of extreme retraction from said saw blade and means responsive to the completion of a said stepwise transporting movement.

7. Apparatus to be used in forming a series of transverse deflected slots penetrating edgewise into but not completely across a keyboard blank in the production of keys for pianos and analogous musical instruments,

said apparatus comprising: cutting means including a saw blade, a drive for said blade, a first carrier member supporting said blade and said drive, and guide means for directing reciprocating movements of said blade toward and away from a keyboard carrier; drive means for said carrier member; carrier means for supporting and manipulating a keyboard blank generally in a plane perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting said platform member on said base, first guide means for directing rotary movement of said first carrier member about an axis generally perpendicular to said plane, and second guide means for directing reciprocating movements of said second carrier member in a path generally toward and away from said saw blade; drive means connected to said second carrier member for causing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting at the rear edge thereof and whereby to separate said blade and said blank after the formation of a second straight-line cut confluent with and deflected from said first cut; rotary drive means connected to said first carrier member for rotating said first carrier member and thereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second cuts, said rotary drive reversibly rotating said first carrier member through said predetermined angle upon completion of said second out and upon withdrawal of said blade to the deflection point between said cuts; drive means operatively connected to one of said cutting means and said carrier means for incurring straight-line, relative converging and separating movements thereof between the rotation and the reversible rotation of said first carrier member for urging said saw blade and said keyboard blank into cutting relationship in forming said second straight-line cut; and indexing means for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon separation of said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank.

8. Apparatus to be used in forming a series of transverse deflected slots penetrating edgewise into but not completely across a keyboard blank in the production of keys for pianos and analogous musical instruments, said apparatus comprising: cutting means including a saw blade and a drive for said blade, said blade being suffi ciently narrow to permit relative turning in a said blank for making a said efiected slot; carrier means for supporting and manipulating a keyboard blank generally in a plane perpendicular to said saw blade, including a stationary base, a platform member adapted to receive said keyboard blank, relatively movable first and second carrier members mounting said platform member on said base, first guide means for directly rotary movement of said first carrier member about an axis generally perpendicular to said plane, and second guide means for di recting reciprocating movements of said second carrier member in a path generally toward and away from said saw blade; drive means connected to said second carrier member for causing movement of said second carrier member in a path generally toward and subsequently away from said saw blade whereby to converge said saw blade and said keyboard blank into cutting relationship in forming a first straight-line cut in said blank starting at the rear edge thereof and whereby to separate said blade and said blank after the formation of a second straight-line cut confluent with and deflected from said first cut; rotary drive means connected to said first carrier member for rotating said first carrier member and thereby said keyboard blank through a predetermined angle upon completion of a said first cut, said predetermined angle corresponding to the angle of deflection between said first and second cuts, said rotary drive reversibly rotating said first carrier member through said predetermined angle upon completion of said second cut and upon withdrawal of said blade to the deflection point between said cuts; drive means operatively connected to one of said cutting means and said carrier means for incurring straight-line, relative converging and separating movements thereof between the rotation and the reversnew blade and said keyboard blank into cutting relationship in forming said second straight-line cut; and indexing means for incurring relative stepwise transporting movements between said cutting means and said keyboard blank upon separation of said saw blade and said blank, said stepwise movements occurring along a path in said plane and generally parallel with the longitudinal axis of said blank, said stepwise movements corresponding to the spacings between the individual deflected slots being made in said blank.

References Cited in the file of this patent UNITED STATES PATENTS Shailer et a] Sept. 15, 1896 Jotzen Nov. 28, 1922 Wilkie Sept. 29, 1942 Svikhart July 18, 1944 Grob et a1. Dec. 12, 1944 Francis Feb. 28, 1956 Davis July 17, 1956 Crane Dec. 18, 1956

Claims

1. APPARATUS TO BE USED IN FORMING A SERIES OF TRANSVERSE DEFLECTED SLOTS PENETRATING EDGEWISE INTO BUT NOT COMPLETELY ACROSS A KEYBOARD BLANK IN THE PRODUCTION OF KEYS FOR PIANOS AND ANALOGOUS MUSICAL INSTRUMENTS, SAID APPARATUS COMPRISING: CUTTING MEANS INCLUDING A SAW BLADE AND A DRIVE FOR SAID BLADE; CARRIER MEANS FOR SUPPORTING AND MANIPULATING A KEYBOARD BLANK GENERALLY IN A PLANE PERPENDICULAR TO SAID SAW BLADE, INCLUDING A STATIONARY BASE, A PLATFORM MEMBER ADAPTED TO RECEIVE SAID KEYBOARD BLANK, RELATIVELY MOVABLE FIRST AND SECOND CARRIER MEMBERS MOUNTING SAID PLATFORM MEMBER ON SAID BASE, FIRST GUIDE MEANS FOR DIRECTING ROTARY MOVEMENT OF SAID FIRST CARRIER MEMBER ABOUT AN AXIS GENERALLY PERPENDICULAR TO SAID PLANE, AND SECOND GUIDE MEANS FOR DIRECTING RECIPROCATING MOVEMENTS OF SAID SECOND CARRIER MEMBER IN A PATH GENERALLY TOWARD AND AWAY FROM SAID SAW BLADE; DRIVE MEANS CONNECTED TO SAID SECOND CARRIER MEMBER FOR CAUSING MOVEMENT OF SAID SECOND CARRIER MEMBER IN A PATH GENERALLY TOWARD AND SUBSEQUENTLY AWAY FROM SAID SAW BLADE WHEREBY TO CONVERGE SAID SAW BLADE AND SAID KEYBOARD BLANK INTO CUTTING RELATIONSHIP IN FORMING A FIRST STRAIGHT-LINE CUT IN SAID BLANK STARTING AT THE REAR EDGE THEREOF AND WHEREBY TO SEPARATE SAID BLADE AND SAID BLANK AFTER THE FORMATION OF A SECOND STRAIGHT-LINE CUT CONFLUENT WITH AND LATERALLY DEFLECTED FROM SAID FIRST CUT; ROTARY DRIVE MEANS CONNECTED TO SAID FIRST CARRIER MEMBER FOR ROTATING SAID FIRST CARRIER MEMBER AND THEREBY SAID KEYBOARD BLANK THROUGH A PREDETERMINED ANGLE UPON COMPLETION OF A SAID FIRST CUT, SAID PREDETERMINED ANGLE CORRESPONDING TO THE ANGLE OF DEFLECTION BETWEEN SAID FIRST AND SECOND CUTS, SAID ROTARY DRIVE REVERSIBLY ROTATING SAID FIRST CARRIER MEMBER THROUGH SAID PREDETERMINED ANGLE UPON COMPLETION OF SAID SECOND CUT AND UPON WITHDRAWAL OF SAID BLADE TO THE DEFLECTION POINT BETWEEN SAID CUTS; DRIVE MEANS OPERATIVELY CONNECTED TO ONE OF SAID CUTTING MEANS AND SAID CARRIER MEANS FOR INCURRING STRAIGHT-LINE, RELATIVE CONVERGING AND SEPARATING MOVEMENTS THEREOF BETWEEN THE ROTATION AND THE REVERSIBLE ROTATION OF SAID FIRST CARRIER MEMBER FOR URGING SAID SAW BLADE AND SAID KEYBOARD BLANK INTO CUTTING RELATIONSHIP IN FORMING SAID SECOND STRAIGHT-LINE CUT; AND INDEXING MEANS FOR INCURRING RELATIVE STEPWISE TRANSPORTING MOVEMENTS BETWEEN SAID CUTTING MEANS AND SAID KEYBOARD BLANK UPON SEPARATION OF SAID SAW BLADE AND SAID BLANK, SAID STEPWISE MOVEMENTS OCCURRING ALONG A PATH IN SAID PLANE AND GENERALLY PARALLEL WITH THE LONGITUDINAL AXIS OF SAID BLANK, SAID STEPWISE MOVEMENTS CORRESPONDING TO THE SPACINGS BETWEEN THE INDIVIDUAL DEFLECTED SLOTS BEING MADE IN SAID BLANK.