Automatic flute grinding machine

An automatic grinding machine adapted to cut and relieve spiral drill flutes and perform analogous form-relieving operations requiring helical advance of the work, wherein a linearly-moving carriage travels a rotary spindle and its work chuck relative to a grinding wheel in programmed duty cycles under control of logic circuitry with optional manual override control. Separate electric motors for the carriage and spindle are activated at adjustable speed ratios by digitally set binary drive pulses enabling instant change of helix angle or lead ratios and other working parameters by adjustment of digital switches at a simple control panel. A reversible tool head affords automatic cross-cutting capabilities; and a system of pulse-controlled indexing of the work is provided to increase the production rate of the machine by a method which effects the indexing as a function of the otherwise idle return travel of the carriage for restarting in successive work excursions.

Various arrangements are known for imparting complex linear and rotary 
motion to a work piece, as by travelling a slide table or carriage upon 
which the work spindle is being rotated simultaneously in progression 
relative to a cutting wheel to produce a spiral trace, as for example in 
forming spiral flutes on drill bodies, reamers, routers, and the like. 
The requisite linear and angular drive components for producing such 
complex work motion may be derived according to known practices from a 
single driving motor in conjunction with various kinds of power take-off 
mechanism involving gearing, cams, sine drives and like arrangements to 
divide the driving torque into linear and angular components; or, in 
accordance with another method, separate driving motors may be employed to 
avoid some of the mechanical difficulties inherent in the unitary 
motordrive systems. Error potential exists in both systems, however; and 
in the case of the more preferential multiple-motor type of drive, 
difficulty is encountered in maintaining a constant driving speed in the 
several motors which becomes particularly critical in precision work or 
where the workig load on the motors is heavy and higher spindle speeds are 
required. 
In accordance with the present disclosures, separate pulse-actuated motors 
are employed to drive the carriage and spindle under control of 
digitally-set binary drive pulses affording selectably pre-set speed 
ratios determinative of the various helix or lead angles required to be 
imparted to the work as it progresses relative to the grinding wheel. 
In accordance with further aspects of the disclosures, automatic indexing 
of the work to new starting positions during any duty cycle, as in 
grinding multiple flutes each beginning at a certain angular distance away 
from other flutes abut the drill body, is effected during the otherwise 
lost-time return travel of the carriage back to its home position, 
preparatory to restarting in the next working pass, by a method which 
stops the spindle without extinguishing the drive pulses while counting 
and comparing the pulses for both carriage and spindle, and subsequently 
restarting the spindle while the carriage is advancing the work toward the 
wheel and at a certain point in such advance designated as the "Index 
Distance" which is a measure in terms of pulses needed to bring the work 
into engagement with the grinding wheel at the precise index or starting 
position required. 
In accordance with still another aspect of the improvements, the tool head 
is pivotable from one angular cutting position to another crosswise of the 
spindle and work axis to perform reverse fluting and cross-cutting 
operations automatically under control of pesettable digital switch means 
along with the setting of other working parameters at the control panel.

As depicted in FIGS. 1 and 2, the flute-grinding machine includes a number 
of basic components found in machine tools of the class described, such as 
a work spindle 17 supported on a carriage slide or table 10 shiftable 
linearly in the direction of the spindle axis on base structure 11 to 
travel the spindle and its work-holding chuck 25 relative to some form of 
tool or grinding facility, such as the abrasive wheel 13. 
In the present machine the work spindle 17 is equipped with a known form of 
automatic chuck 25, and is journalled in a spindle head 16 adjustably 
seated on the carriage slide 10, the chuck 25 being opened and closed by 
air cylinder means 26 and associated lever-actuating means 27 carried on 
the side of the spindle head. The rearward end of the spindle remote from 
the chuck is fitted with lead-screw means which will preferably be an 
improved form of tracking sleeve comprising a sleeve member 18 provided 
with a helical tracking groove 19 into which projects the end of a 
stationary tracking stylus 20 supported on a fixed post means 21 on the 
machine base and effective responsive to rotation of the sleeve, which 
floats independently about the spindle, to impart a linear thrust to the 
carriage slide for movement thereof between advanced and home positions, 
according to the direction of rotation of the sleeve, and at a rate of 
travel which will depend upon the speed of rotation of said sleeve and the 
lead or pitch of its tracking groove, all in a manner such that the 
concurrent linear motion of slide and rotary motion of the spindle produce 
a resultant compound motion with spiral displacement of the work relative 
to the grinding wheel or other tool when the speed ratios of the driving 
motors are set at appropriate speed ratios. 
In accordance with the invention, the movements of the carriage and spindle 
are effected by separate pulse-controlled motors 30, 40 carried on a 
mounting plate 15 footed on the spindle head 16, motor 30 being coupled to 
the lead-screw means or tracking sleeve 18 by gear belt 31 trained over a 
gear 32 fast on the sleeve, while motor 40 is similarly coupled by gear 
belt 41 working in a gear 42 which is fast with the spindle, said motors 
being supplied with driving pulses generated by circuit means described 
hereafter. 
The tool head 12 with its cutting wheel 13 and driving motor 14 is adapted 
to rise and descend as a unit in known manner under control of a 
corresponding air cylinder mens, indicated at 83 in FIG. 2, to shift the 
grinding wheel to and from cutting engagement with the work carried in the 
spindle chuck. A steady-rest structure equipped with novel tool rest means 
60 is actuated by its corresponding air-cylinder means 67 to rise or 
descend from work-supporting level beneath the chucked work piece in timed 
relation with the movements of the tool head and action of other machine 
components including the carriage slide 10, chuck 25, and a loading 
plunger 50, in duty cycles which will effect the loading of a drill blank 
automatically into the chuck, formation successively of multiple flutes 
thereon, and discharge of the finished drill body from the chuck at the 
conclusion of the cycle, with the carriage, chuck, and loading means 
standing in certain normal starting conditions in readiness for succeeding 
cycles. 
The novel tool-supporting means 60 for forming part of the steady rest 
structure, as detailed in FIGS. 4, 5, and 5-A, is especially adapted to 
provide precision support for the drill bodies, and takes the form of a 
head block 60 carried at the upper end of a vertically-shiftable steady 
rest post 60A, said block having a square cross-section with two adjoining 
sides seating slideably into the trough of a V-shaped groove in a slideway 
block 61 into which the head block is seated by the thrust of roller means 
62 carried on a pivot bracket 63 pivotally joined at 63A to a dog-leg 
lever 64 which is urged by adjustable spring means 65 to press the roller 
against the block 60 on the side opposite from the slideway. 
One end of the dog-leg lever is pivotally connected as at 64A to the 
vertically shiftable steady-rest post 60A, while the opposite end thereof 
connects pivotally with the plunger of an air cylinder 67 operative 
reversely to raise or lower the post 60A and elevate or retract the block 
60 from supporting position beneath the drill bodies or other work piece. 
As depicted in FIGS. 5 and 5-A, the top of the block 60 is faced to provide 
a small land in which is formed a gib track 69 of short horizontal extent 
and having a dovetail cross section and separated by a slit down the 
middle, as at 69A, so that one-half of the gib track shifts laterally of 
the other half to permit substitution of drill-seating blocks by varying 
the width of the gib track groove responsive to turning of a set screw 
69B. The gib has a V-shaped drill-seating groove 69C conformably with the 
diameter of the drill bodies to be supported. The function of this tool 
rest is such that when the post and block means 60, 60A rises beneath the 
chucked drill piece, the V-shaped seating groove will interfit with the 
cylindrical drill body and contact the same at two points as indicated in 
dotted lines in FIG. 5-A, while leaving a short end portion of the drill 
projecting into space in exposure to contact by the grinding wheel. The 
post 60A is provided with adjusting screw means 68 (FIG. 4) operative to 
set the upper limiting level of the tool rest when rising to supporting 
position. 
With reference to FIGS. 1 and 2, blank drill bodies 28 are stacked in a 
gravity-feed magazine 29 having a bottom exit overlying a seating slot 51 
formed in the end of a loading plunger 50 such that when the plunger 
starts at home position beneath the magazine (FIGS. 2 and 4) it will pick 
up one blank in said seat and transport it into the open chuck at a time 
when the tool head and steady rest are withdrawn to non-obstructing 
positions, these latter actions, as will appear more fully hereafter, 
preferably being made to occur substantially simultaneously. 
The loading plunger 50 is advanced and retracted by respective air 
cylinders 52 and 53, FIG. 2, to which compressed air will be admitted by 
operation of corresponding reverse-acting solenoid valve means 86A and 86B 
responsive to closure, in the manual operation, of "Load" and "Return" 
switch contacts 94A, 94B to energize the corresponding solenoid windings 
86C, 86D, it being observed that the latter, and all of the other valve 
solenoids are maintained in their respective operative states by 
conventional solid-state relay means, such as 86E, 86F, utilizing Triacs, 
essentially identical air-cylinder and valve means being provided, as 
shown, to activate the other basic machine components in both the manual 
step-by-step mode and the automatic mode, including specifically the tool 
head 12, chuck 25, and steady-rest means 60, the circuit connections for 
the respective control solenoids, actuating switches, and supervisory 
switch means being brought to plug terminals (not shown) for cable 
interconnection with a control unit 70 including programme and control 
switches, logic, motor pulsing and translating circuitry, as described 
hereafter. 
Supervisory limit switch means operative to signal the position of the 
carriage at its forward and home limiting positions respectively, 
comprises the carriage limit switches 22, 23, activated by adjustable trip 
nuts 24A, 24B, on the carriage; together with "Load Plunger" limit 
switches 57 and 58 activated by an adjustable trip rod 56 travelling with 
the plunger and actuating said switches in the advanced loading position 
when the drill blank is fully inserted into the open chuck, and the fully 
retracted condition of the plunger in readiness for the next loading 
advance. 
STEP-BY-STEP OPERATION IN MANUAL MODE 
For purposes of a generalized explanation of the operation of the machine 
in the manual, step-by-step mode, it may be assumed that some desired 
helix angle determined by the ratio of the rate of advance of the carriage 
slide 10 to the speed of rotation of spindle 17 has been set up on the 
thumbwheel or dial switch means on the control unit 70, FIG. 2, as by 
adjusting the "Table" switch 71 and the "Spindle" switch 72, whereby the 
appropriate stepping rates for the motors 30 and 40 will be determined, it 
being assumed further that the required "Index Distance" 2000 has been 
indicated on thumbwheel switch means 73 to determine the number of motor 
steps required for the desired amount of angular resetting or indexing 
displacement of the spindle to new starting positions for the appropriate 
number of flutes selected, the number of which will be indicated by the 
setting on the "Index No." switch 74 (2 flutes in this example), all such 
set up parameters being conveniently read from prepared tables showing the 
settings for various sizes of drills with various spiral leads. 
At the beginning of a cycle the carriage 10 will normally stand returned to 
home position (toward the left, FIG. 2) and carriage limit switch contacts 
23 will be closed, as will be also the plunger limit switch contacts 57 
with the loading plunger 50 standing in home position (toward the right); 
also the tool head 12 and steady rest 60 will be withdrawn from their 
respective operative positions and the chuck 25 will stand open. A blank 
drill body will be lodged in the open chuck by operation of the "Load" 
switch to close its contacts 94A, thereby energizing the appropriate 
solenoid winding 86C to admit air to the "Load" plunger cylinder 53 
causing plunger 50 to advance the drill blank seat 51 into the open chuck. 
Operation of the "Chuck" switch to close contacts 90B will energize the 
appropriate solenoid valve winding 86C to cause air cylinder means 26, 27, 
to close the chuck, whereupon operation of the plunger "Return" manual 
switch closing contacts 94B will cause the loading plunger to be retracted 
to "home" position by action of air cylinder 52. 
The tool rest will rise to work-supporting position responsive to operation 
of the loading limit switch 57 when the load plunger returns to home 
position, the contacts of this switch being preferably connected in 
parallel with steady-rest conductor 91 so that the steady-rest must start 
down as the load plunger starts forward and vice versa and the rest cannot 
start up before the plunger has started back to its retracted or "unload" 
position. Thus when switch 57 operates the steady-rest rises into 
supporting engagement with the work and the tool head descends to working 
level to engage the cutting wheel with the supporting workpiece. In the 
manual mode, movements of the carriage must be effected by the Jog 
Switches 92A, 92B, and there is no automatic indexing of the work. 
AUTOMATIC MODE 
CONTROL UNIT AND BLOCK DIAGRAM 
The manual override switches mentioned in view of FIG. 2 and more 
particularly detailed in FIG. 9, are intended primarily for job set-up and 
checking purposes and are conveniently arranged on the panel of a compact 
and essentially portable control unit 70, such as depicted in FIG. 7, 
along with the digital thumbwheel switches 71-74 which control the 
pulse-drive means for the carriage and spindle motors M-1, M-2, and 
automatic indexing drive means and control circuitry, all of which is 
further illustrated schematically in the block diagram of FIG. 8 wherein 
programming logic subcircuitry is represented by logic cards L-1 and L-2 
having inputs extended thereto via cable means 70C from the carriage limit 
switches 22, 23, and the loading plunger limit switches 57, 58, with 
output control signals via Solid State Realys 86E...86F returned to the 
machine to activate the respective Air Cylinder Solenoids and appertaining 
valves which in turn actuate the Air Cylinders according to the programmed 
duty-cycle sequence. 
The general programming or duty-cycle logic is detailed in FIGS. 16A 
through 18, while other logic circuitry pertaining to pulsed drive of the 
motors, as such, and setting of the speed ratios and indexing operations 
is included on appertaining frequency dividing and translating cards in 
unit 70 to enable setting of the "Index Distance" (angular displacement of 
the spindle for successive flute-starting positions) and the "Index 
Number" (number of flutes required to be cut in the same duty cycle) which 
depend upon activation of the motors by binary pulses under control of the 
aforesaid digital switch means, as will further appear in view of the more 
detailed description of the motor pulsing subcircuitry shown in FIGS. 8 
and 10 through 15. 
Carriage and spindle motors M-1, M-2, suitable for actuation by binary 
pulses may take the form of stepping motors 30 and 40 having windings as 
indicated in FIG. 8, which are successively energized to advance their 
respective drive shafts responsive to binary pulses applied repetitiously 
in the sequence indicated in FIG. 8 at the respective motor terminals 
designated A, C, B, D and A, C, B, D, as outputs from corresponding Master 
and Slave Translating Circuits TC-1, 2, 3, 4, detailed aspects of which 
are further described hereinafter in view of FIGS. 14 and 15. 
INDEXING METHOD 
The spindle is indexed to successively new starting position, as in cutting 
multiple flutes each equidistantly separated from the others, during 
lost-time return travel of the carriage by the method of rendering the 
spindle pulses temporarily ineffectual beginning at the instant a given 
flute or other cutting operation is finished and counting both carriage 
and spindle pulses until a signal is produced as the result of a 
comparator circuit match between the "Index Distance" value set on digital 
thumbwheel switch 71 and an equivalent count of blanked drive pulses as a 
parameter which equates to the distance the carriage must travel after the 
spindle is restarted in rotation so that the workpiece will meet the 
grinding wheel at the precisely correct starting or index position for the 
next flute or other cut. 
Reference tables are prepared giving the "Index Distance" in terms of 
digital pulse values for different types of work, along with the relative 
pulse values for determining the carriage and spindle speed ratios which 
correspond to a wide range of helix or spiral lead angles so that the 
machine operator can quickly enter the necessary settings for any type of 
work into the digital switches 71 to 74. 
The described indexing methods represent a substantial savings in lost time 
by which the production rate of the machine can be greatly increased over 
other types of machine in many of which the carriage or spindle or both 
must be stopped while the indexing adjustments are made. By setting the 
reverse drive speed for the carriage at potentiometer 79B the return 
travel of the carriage is speeded up so that the production rate for the 
machine can be increased by as much as thirty percent over other types 
employing conventional indexing methods. 
AUTOMATIC MODE LOGIC CIRCUITRY 
In accordance with FIGS. 2, 8 and 9, the several machine activating 
components, such as the air cylinders and solenoids, and the respective 
limit and manual control switches, have terminal connections extending 
into the control unit 70 via cable mens 70C, wherein the limit switches 
connect with terminals (A3) (A4) (A5) and (A6), FIG. 9, and respectively 
act through corresponding noise rejection means comprising inverters Z-1 
and Schmitt triggers Z-2, such signals being then directed into the logic 
circuitry according to FIGS. 16 to 18, as will further appear. 
The respective pushbutton switches 76 and 90A, -B...94A, -B, involved in 
cycling the machine and variously actuating the solenoid valve means, 
stand normally open and when closed will apply ground, as at terminals 
(A15) to (A24), to sink the indicated normal +5 volt stabilizing pull-up 
bias maintained on the corresponding inverters Z50A to Z50F and Z43, 
respectively connecting to terminals (A27) through (A32) and (B32), FIG. 
9, for extension via cable 70C into the logic cards L-1, L-2, whereby to 
produce requisite output signals responsive to actuation of the 
appertaining manual switches at the binary "HIGH" and "LOW" values as 
indicated. 
Mode switch contacts 75A connecting with terminal (A25) are normally open 
and will inhibit automatic operation due to the state of gate Z38 and 
enable single step operation as the result of the condition on output (SS) 
due to open contacts 75B, and vice versa, to enable automatic operation 
due to the signal on "Auto." output (14) when the switch is changed to the 
automatic mode. 
Power to the grinding wheel motor 14 is provided by closure of the "Wheel 
On" switch contacts 77A to energize the winding 78 of relay Z36 at 
terminal (A9) via normally closed manual "OFF" contacts in series with the 
"ON" contacts (when closed), and power at terminal (A9) of the relay will 
establish its own holding circuit at relay contacts 78A via terminal 
(A10), such holding circuit being broken to drop the relay and stop the 
wheel motor responsive to actuation of the manual "OFF" switch and 
resultant opening of its contacts 77B. Voltage present on the relay 
winding in the aforesaid holding condition will apply a "Wheel On" signal 
to the logic system via another inverter Z-1E. 
MOTOR PULSE GENERATING MEANS 
Driving pulses for the two motors, M-1, M-2, are produced by a master 
pulse-generating means in combination with frequency dividing means and 
translating means, wherein two pulse generators or oscillators of 
identical character are used for forward drive and reverse drive in order 
to achieve stability and accuracy with minimal adjustment problems. As 
shown in FIG. 10, the two generators or oscillators Z 22 and Z 23 and 
associated circuitry are substantially identical, so that only the forward 
driving embodiment will be described. 
A forward command signal at input (4) will be applied to oscillator Z 22 
via inverter Z 9A, a combination ramping and constant-current subcircuit 
comprising another inverter Z 9B, unijunction transistor Q 2 and a control 
capacitor of about 5 mfd., and a voltage-dropping means including diodes 
Da, Db and transistor Q1, with resultant triggering of an oscillator 
output which is passed through a wave-shaping and degliching subcircuit 
comprising unijunction transistor Q 3 and a Schmitt trigger Z 15 to 
provide a clean square-wave output pulse on conductor 109, via gates 
Z-16A, -B, and -C. Gate Z 10A makes available a source of counting pulses 
on output conductor (10) for utilization in other subcircuits. 
The basic pulsing rate can range from 3000 to 300,000 pulses per second and 
can be modified for speed and ratio purpose in three ways: by adjustment 
of the "Forward Speed" potentiometer 79A (or "Reverse" potentiometer 79B) 
on the control panel, which is connected to the appertaining pulse 
oscillator at terminals 5 and 6 thereof (or terminals 15 and 16 for the 
"Reverse" oscillator), adjustment of which will afford an approximately 
10:1 speed adjustment range; or alternatively by actuating either digital 
ratio control 71, 72, FIG. 7, to a setting of 10 through 99 at the control 
panel to disable a "Divide-By-Ten" Counter means Z 2E providing a higher 
pulse rate at the (D 10) output via gate Z 10B, the normal output 
"Dividie-By-Ten" being gated at Z 16B to appear on output (D 1). 
Both pulse generators provide a "Low" speed which will be available as the 
result of operation of potentiometers 79A, 79B, connecting to terminal 7 
at the oscillator and having the effect of shorting or grounding out 
capacitor 110 to produce a lower driving pulse rate, it being observed 
that the reverse-driving generator circuit affords the same drive at 
terminal (A 17) under control of panel switch 79R. 
The aforesaid ramping subcircuits provide an accelerating influence on the 
motors in order to overcome their inherent inertia when starting or 
reversing. 
Arbitration logic controls the second of the tree speed control methods and 
is provided by the arrangement shown at the lower left of FIG. 10 for the 
purpose of reducing somewhat adjustments by the machine operator in 
changing the helix angles or table to spindle ratios in cases where there 
is a large change in the indicated ratios at the switches 71 and 72. 
Input 11 connects with the tens digit terminal of the "Frequency Dividing" 
circuit (to be described) for the spindle rate, while terminal 12 connects 
with the like terminal of the "Frequency Dividing Means" for the carriage 
slide and the signals from both are applied to a four-input gate Z 10D, 
the output of which connects with the "Divide-By-Ten" input of Gate Z 10B 
and also to inputs on gate Z 10E with the output of the latter connecting 
to the "Divide-By-One" input of Gate Z 16C. 
The purpose of the foregoing arbitration logic subcircuitry is to detect 
large changes in the ratio digits, and the effect is to make a 10:1 
adjustment in speed in such cases to save set-up and checking time of the 
operator. 
For example, in order to flute a No. 75 drill body at a helix angle of 
28.degree., the dial switches 71, 72 will be set at 25/50, signifying that 
for every 25 steps of angular movement of the spindle the table must 
advance by 50 steps in order to yield the required lead of 0.125 inches 
per revolution at the angle specified. However, if the next job requires a 
setting of 74/25 for the same angle, as would be the case of a 1/8-inch 
drill with a lead of 0.740 inch, the speed change for the new ratio is 
considerable, but the set-up is simplified for the operator nevertheless 
because the automatic adjustment of the speed by a factor of 10 scales the 
relative magnitude of the manual adjustment down from 74 to 7.4. 
FREQUENCY DIVIDING AND INDEXING CIRCUIT MEANS 
The frequency-dividing circuitry includes three subcircuit arrangements 
comprising, respectively, a first divider for the carriage slide or table 
motion component, as illustrated in FIG. 11, and a second divider for the 
spindle rotary motion depicted in FIG. 12, together with a subcircuit for 
indexing, as set out in FIG. 18. 
The said frequency divider circuits are essentially alike with the 
principal difference that the circuit of FIG. 11 includes a timing means Z 
38B supplying a "WAIT" or delay signal, utilized in other subcircuits, and 
triggered by a blanking signal derived from the indexing circuit of FIG. 
18. 
Accordingly, and with these differences understood, only the divider 
circuitry for the carriage motion will be described in detail. 
Referring to FIG. 11, the ratio or motor-stepping speeds are controlled 
primarily by thumbwheel switches 71 and 72, FIGS. 2, 7, 8, which are 
conventional digital binary-coded decimal switches respectively operable 
to set the values of the numerator and denominator of the 
carriage-to-spindle speed ratios in a range from decimal 01:01 to 99:99, 
and provide digital input signals to the frequency divider circuitry 
weighted accordingly, the TENS values being applied to terminals B-23, 
-24, -25, -26, and the UNITS values being applied to terminals B-27, -28, 
-29, -30. 
The pulses from the master oscillator or pulse-generating means appearing 
at output 10 in FIG. 10 are applied to input terminal A 3 in FIG. 11 to 
trigger a first sample-pulse timer Z 45A, which may be a resettable 
monostable dual timer type 74123 provided with a 100 NS delay circuit 
connected to trigger a second such timer Z 38A via gate means Z 8A 
incorporating a 10 MS delay and providing a first output at Q 12 extended 
via conductor 111 for a pair of tens and units counting synchronous clocks 
Z 46, Z 53 (e.g. 74160) as a clearing signal, and a second drive pulse 
output at terminal A 5 which is gated by gates Z 34A and Z 34B and 
respective inverters Z 17A and Z 17B to apply forward and reverse carriage 
slide or table drive signals on corresponding terminal B-8 and B-9, 
control signals for gating these pulses being applied to forward input and 
reverse input terminals B 20 and B 30, respectively, passed by gate Z 34A 
and inverter Z 17A to terminal B 9, as the forward slide travel source 
responsive to the forward gating signal for forward slide travel applied 
to gate Z 34A at terminal B 20. Driving pulses from Q 5 are also passed by 
another gate Z 34B and inverter Z 17B to terminal B 8 for use in the 
reverse slide drive, all such driving pulses, however, including those for 
the spindle in the corresponding pulse outputs of FIG. 11, being applied 
to the motor windings through the translating circuitry to be described 
hereafter. 
In the aforesaid fequency dividing circuit, a blanking signal for indexing 
purposes is applied to the third timer Z 38B for trigering the "WAIT" or 
delay pulse to be provided at output 19. 
The counter outputs are respectively passed via inverters, such as Z 34A, 
-B, -C, and -D, for the TENS counters, and Z 25A, -B, -C, -D to the inputs 
of the corresponding comparators (e.g. 8242 types) Z 54, Z 47, for which 
the corresponding reference inputs from the thumbwheel switches 71, 72, 
are connected to input terminals B 27, B 28, B 29 and B 30 for the UNITS 
values. Coincidence between the thumbwheel inputs, clock outputs, and 
sample pulse governs the frequency dividing function of the timers 
according to the setting of switches 71 and 72. 
Monitoring of the carriage-to-spindle speed ratios by the arbitration 
circuit means of FIG. 10 is achieved in respect to the carriage slide or 
table component by Gate Z 31A FIG. 11) whose four inputs connect to the 
reference inputs to the TENS comparator Z 54 and look at the TENS input 
from the thumbwheel switch 71 to determine whether or not they equate to 
zero and adjust the motor pulsing speed accordingly, as explained in view 
of FIG. 10. The output of this monitoring gate connects from terminal B 4 
to the carriage slide or table arbitration logic input 12 in FIG. 10. 
Substantially the identical ratio monitoring means is employed for the 
spindle speed divider shown in FIG. 12 at Z 31B whose output at terminal B 
5 connects with the arbitration logic input terminal 12 in FIG. 10, to 
control the pulsing rate for the spindle dependently upon the presence or 
absence or ratio change occasioned by changing the setting of thumbwheel 
switches, as described. 
The frequency-dividing circuitry for the spindle speed component, as 
depicted in FIG. 12, is essentially the same as that described in view of 
FIG. 11 with respect to the connections and operations of the synchronous 
clocking means, comparators, thumbwheel switch inputs from the spindle 
switch 72, sample pulse timer Z 45B and timer means Z 52 for the spindle 
stepping rate. The dividing circuit omits a timer comparable to Z 38B in 
FIG. 11 for producing delay signals, and, instead, includes an additional 
gating means Z 55 activated by the blanking signal applied at input 112 to 
signal stoppage of the spindle motor for the duration of the required 
indexing count via gate Z 34D and inverter Z 24B to spindle pulse output 
terminal A 8, which together with the spindle forward output at terminal A 
9 will be applied to the spindle motor through the translating circuitry 
hereafter described. The clock Z 32 and Z 39 and comparators Z 40 and Z 33 
may be of the same types as described in the table or carriage slide 
frequency divider of FIG. 11. 
INDEXING LOGIC AND COUNTER 
Referring to FIG. 13, the indexing operation occurs only in the automatic 
mode as the result of an enabling signal from input A-5 to gate Z-28A to 
enable a flip flop Z-1 (e.g. Type 7474). 
The Index signal from the carriage slide limit switch 23 appears on input 
terminal A-4 to trigger the flip flop and stop the spindle instantly, by 
producing a blanking signal from its output Q on conductor 113 and to 
enable the indexing counting means Z-4 to Z-7, as will appear more fully. 
In order to assure a clean spike-free counting pulse, pulses from the 
master source designated "R-Step" at Gate Z-8B are used to trigger a 
one-shot timer Z 2F (Type 74123) to generate sample triggering pulses 
applied to the flip flop via inverter Z-9F and gate Z-8A and gate Z-28A, 
to provide rapid, glich-free counting. The blanking signal is available at 
output 114. The "R-Step" input enables the one-shot timer operation via 
gate Z-8B to sustain the pulsing of the flip flop and apply resetting 
signals to the decade counters Z-4 to Z-7, and to continue the blanking 
signals from Z-1. 
The index counters are being continually set and reset to no effect in the 
absence of blanking pulses, but the index signal starts the flip flop 
blanking operation and thereby causes the counters to start the index 
count, which will continue until comparators Z-18, -19, -20, and -21 (e.g. 
Type 8242) match the count set up by the binary-coded outputs of "Index 
Distance" Thumbwheel Switch 73 which appear at the bracketed circuit board 
inputs 115 of the comparators designated in FIG. 13 as A-10 to A-17, and 
B-10 to B-17, the counting states of the decade units being applied to the 
comparator inputs in each instance through inverters such as Z-9, Z-12 and 
Z-13 to apply pull-up voltage. 
When the pulse count matches the thumbwheel count at the comparators, a 
signal via conductor 107, via gate Z-8A to NOR gate Z-28A, will disable 
the flip flop and stop the index blanking so that spindle rotation can be 
resumed. 
The number of times this indexing operation can occur depends upon the 
setting of the "Index Number" thumbwheel switch 74 and an associated index 
pass counting subcircuit comprising part of the logic circuitry to be 
described. 
MOTOR PULSE TRANSLATING MEANS 
The driving pulses provided by the basic frequency generating means must be 
applied to the multiple windings of the respective motors in requisite 
sequence and direction according to the pattern mentioned under FIG. 8, 
for which purposes translating circuitry of the type depicted in the 
companion master and slave subcircuits shown in FIGS. 14 and 15, is 
provided for the motors 30 and 40 to switch and steer the pulses and 
provide phase shift and amplification for the working levels to about 3 
amperes per motor, and to assure that the motors do not get out of step. 
FIG. 14 shows a master phasing generator and power amplifying means serving 
four of the eight windings of motor 30, while FIG. 15 depicts a companion 
phasing circuit operating as a slave to the master circuit but having its 
outputs displaced from those of the master circuit by 45.degree. for 
energization of the remaining four windings of motor 30. 
The translating circuits of FIGS. 14 and 15 are represented in FIG. 8 by 
the "Translating" circuit cards TC-1, TC-2, and it is to be understood 
that an identical set of circuit cards TC3, TC-4 will duplicate the master 
and slave translating circuits for the Spindle Motor 40, as shown, so that 
it is deemed unnecessary to repeat the description of the translating 
circuits for motor 40. 
Forward or reverse driving pulses from terminals B9 or B8 of FIG. 11 
applied to either of the corresponding input terminals 23 or 24 of FIG. 14 
will gate clocking pulses via corresponding inverters 201 or 202 and gate 
203 to JK type Flip Flop 204 having its respective outputs Q and Q 
connecting through respective gates 205, 206, to provide a "Slave Forward 
Lo" output at terminal 233 and a "Slave Reverse Lo" output to terminal 234 
respectively interconnecting with the "Forward Lo" input 23 and "Reverse 
Lo" terminal 24 in the slave circuit of FIG. 15. 
Additonally, output Q and Q from 204 are steered by the arry of AND Gates 
207, 208 and the OR Gate 209 to provide pulses via inverter 210 and 
conductor 211 to corresponding power transistor amplifying means 212 and 
213, the outputs of which appear at motor drive terminals 214, 215 for 
energization of two windings of motor 30. 
Another two motor windings then are energized by pulse outputs from Q and Q 
terminals of Flip Flop 204 applied via a similar array of gates 220, 221 
and 222 driving amplifiers 225, 226 via conductor 223 and inverter 224 
providing the outputs at another pair of motor drive terminals 227 and 
228. 
The remaining four windings of motor 30 are pulsed under control of the 
slave subcircuits of FIG. 15 responsive to signals on either the "Slave 
Forward Lo" or "Slave Reverse Lo" input terminals 223 F or 224 R from the 
corresponding outputs 233 or 234 of FIG. 14, along with signals from 
master unit outputs (FIG. 14) to inputs bracketed at 230, 231 and 232 from 
its circuit board terminals 26, 27, and 28, in response to which the array 
of AND Gates 240A to 240D and OR Gates 240E to 240F will be switched by 
the JK Flip Flop 240G under control of clocking pulses via gates 244, 245, 
to apply sequential inputs via inverters 247A and 247B to corresponding 
transistor amplifier units 248A and 248B with resultant power pulse 
outputs on motor drive terminals 250 and 251 providing driving pulses for 
two more of the remaining four motor windings. 
The last two windings of motor 30 are pulsed in sequence (FIG. 15) by 
identical switching and steering operations afforded by the similar array 
of gates 241A to 241F and the associated Flip Flop 241G driving two 
remaining transistor amplifiers 248C and 248D through inverters 247C and 
247D to provide power outputs at terminals 252 and 253. 
In the block diagram of FIG. 8, the circuitry of FIGS. 14 and 15 is 
represented by the two translating circuit cards TC-1 and TC-2 with 
outputs via cable MC-1 connecting with the winding terminals D, B, C, A 
and D, B, C, A, of motor 30 for energization in the phased order AC, BD, 
CB DA; BD AC, DA CB; etc. repetitiously. Identical master and slave 
translating circuitry represented by cards TC-3, TC-4 connects via cable 
MC-II to the like terminals of motor 40 for energizations of the windings 
in the same phasing order 
Since the two motors 30 and 40 are activated from the same master source of 
drive pulses, and each motor is locked into the requisite phasal 
energizing sequence of its multiple windings by the described master-slave 
translating means, the motors' output shafts tend to rotate in step at 
their respective preset ratio speeds. 
LOGIC SUBCIRCUITS FOR STEP BY STEP AND AUTOMATIC CONTROL 
FIGS. 16-A through 18 depict related logic subcircuits having inputs and 
outputs respectively identified by legends for utilization and 
interconnection to produce the described machine operations in both step 
by step and automatic duty-cycle sequence, it being understood that such 
circuitry is intended as illustrative rather than limiting except as may 
be specified in the appended claims, and accordingly is subject to 
variation by those skilled in the art. 
Specifically, FIG. 16-A provides a terminals A11, A12 the "Forward" and 
"Reverse" High signals for advancing and returning the carriage slide, 
together with a "Reverse" Low supervisory signal at output 116, the 
forward travel being governed by gates Z51A and Z52A from inputs bracketed 
at 121 including "Wheel On" Low, "Slide Forward" Low, and the 
"Plunger-Returned" Limit Switch 57 (also referred to in the logic legends 
as the "Unload" signal to distinguish it from the forward loading 
condition of the plunger) from the output of gate Z38C, responsive to 
gating by Z38A conditioned by the Automatic Mode Switch 75B, contacts 75A 
(FIG. 9), such that the loading plunger must be returned, the slide 
forward, the grinding wheel on and the machine cycled in order to produce 
the "Forward" High signal at A11 which will start the carriage forward. 
Similar control of the "Forward" High signal is available from the manual 
"Forward Jogging Push Button" Switch 92A in applying a Low via inverter 
Z37C to gate Z38B and gate Z51A via Z38C, which likewise produces the 
"Forward" High at A11 for jogging in setting up or special work. 
To return the slide home, the "Reverse" High signal at the logic board 
terminal A12 requires a "Wheel-On" input to gate Z4AA; closure of the 
"Slide Forward" and "Plunger Returned" limit switches, and operation of 
the "Reverse Push Buttom" switch 92B (FIGS. 2, 7 and 9), together with 
existence of either an "Automatic" High and "Reverse" Flip Flop signal on 
the input of gate Z19B if in the automatic mode, or an operation of the 
"Reverse Push Button" switch to produce the reversing signal responsive to 
the resulting states on gates Z19A and E, and Z4A, Z45 and Z52B. The 
"Reverse" Low on terminal 116 is an availability signal for supervisory 
application within the logic. 
FIG. 16-B provides, via gates Z10A and Z24B, respectively, the enabling 
"Forward" High and "Forward"Low Flip Flop signals at output terminals 133 
and 134 dependently upon the presence of designated signals at the 
bracketed inputs 135, including "Safe" High and "Half Done" Low signals 
from the logic system operative via gates Z19C, Z31D, and Z31E to permit 
indexing to finish a second flute provided the wheel is up, the plunger 
returned, and the carriage returned home in the automatic mode, such input 
signals being provided by the outputs 118, 119 and 120 of FIG. 16-C. 
FIG. 16-D provides two supervisory signals including a "Cycle On" High at 
output 122 governed by the bracketed inputs 124 and gates Z17C, Z17D, Z31, 
Z3 and Z10B with inverter Z24A providing at output 123 an "Unload" signal 
which will permit the chunk to open or unload after the indexing "Count 
Out" starts the last flute and the latter is completed with return of the 
carriage slide, these latter operations involving also the operation of 
subcircuit 16E in which the bracketed inputs 127 will produce a "Reverse" 
Flip Flop High gate Z10C at output 125, provided the "Count-Out" is 
completed and the carriage slide returned to operate its limit switch and 
enable Z10C via inverter Z24B, three-input gate Z51B, inverter Z18A and 
enablement of gate Z10D to provide the "Done" High output 126, indicating 
completion of the last flute with the steady rest going down and the chuck 
opening responsive to output 128 from AND gate Z4A enabled via inputs 129, 
130 and AND gate Z44 enabled by a "Chuck-Open Push Button" Low and "Load 
Remind" Low from inputs 131 and 132. 
FIG. 16-F also governs the "Steady Rest" and "Chuck Opening" signal at 
terminal 128 of FIG. 16-E with respect to automatic and step by step 
operating conditions through the designated interconnection from gate Z3C 
in FIG. 16-E to one input of the OR gate Z3B in FIG. 16-E with the object 
among others of requiring that there be a step by step or "SS" Low manual 
signal and a "Done" High signal input to gate Z11A and a "Done" High on 
gate Z11A or a "Chuck Open" High on gate Z11B to to enable the AND gate 
Z3C signal extended back to FIG. 16-F, as aforesaid, via the NOR gate 
Z51C. Two delay signals are provided at outputs 133 and 134 from the 
outputs of a JK Flip Flop Z28A clocked by "Timer" Z21A triggered by a 
"Load" Limit Switch Low at input one of these delays being extended as an 
input to the aforesaid "Chuck Open" gate Z11B to assure that the "Loading" 
plunger is back before the "Steady Rest" goes down and the Chuck opens. 
FIG. 17-A provides a second source of supervisory delay signals at terminal 
136 from the inverted output Q of Flip Flop Z28B triggered by a "Delay 1" 
High from FIG. 16-F. FIG. 17-A is also the source of a "Load" High signal 
at output 137 from gate Z4B enabled by bracketed inputs 139 when there is 
present a "Chuck Open" High and an "Auto" High on gate Z11B or an "Auto" 
Low and "Load" Push Button Low via inverter Z18C as inputs to gate Z11C 
providing another input to the NOR Gate Z25A. A "Load" Limit Switch Low 
and "Forward" Flip Flop Low on inputs 140 also supply a "Loaded" High 
signal at output 138. 
FIG. 17-B provides "Chuck Closing" High and Low signals at outputs 142, 143 
from gate Z32C and inverter Z18E respectively dependently upon an "Auto" 
High and "Chuck Closed" Push Button Low on gate Z32A or "Auto" Low and 
"Delay 1" Low on gate Z32B in the bracketed inputs 141. This circuit 
further provides "Unload" Low and High signals on outputs 145, 146 
governed by bracketed inputs at 144 including an "Auto" Low and an 
"Unload" Push Button Low via Z18D as inputs to gate Z25D or an "Auto" High 
and "Delay 2" High as inputs to gate Z46, and an "Unload" Limit Switch 
Low, "Auto" High via gates Z39A, Z39B. 
The "Index" High signal is also provided in FIG. 17B at output A13 from a 
gate Z32D and inputs "Auto" Low and "Slide Forward" Limit Switch Low, for 
supervisory use in the logic system. 
FIG. 17-C provides logic signals for controlling the steady rest and 
grinding wheel power and up-down movements with a Steady Rest "Up" High at 
output 150 from gate Z52 when the "Chuck Open" High and "Unload" Limit 
Switch Low inputs are present. The "Wheel On" High at output 151 and 
"Wheel Down" High at output 152 result from bracketed inputs 149 such that 
an input "Wheel On" Low inverted by Z53A, "Unload" Limit Switch High, 
"Reverse" Low to gate Z45, and "Auto" High and "Forward" Flip Flop High 
via AND gate Z46B and NOR gate Z46C, produce the "Wheel Down" Low output 
152 subject to manual inputs "Wheel Down" Push Button Low at Z53, gates 
Z46D and Z4C; and "Auto" Low and "Wheel Up" Push Button Low via gates Z39C 
and Z4C. 
The previously mentioned "Load Remind" signal is produced at output 153 by 
Flip Flop cross-connected gates Z44A, Z44B controlled by a "Load" High 
input via inverter Z18, and a "Load" Limit Switch Low. 
FIG. 18 depicts the Index Pass counting subcircuit for counting the number 
of times the carriage goes forward to provide a "Count Out" High output 
154 to stop the cycle as the result of outputs from "Decade Counter" Z47 
controlled by the designated inputs from the "Forward" Flip Flop Low and a 
"Done" High via inverter Z40A and gate Z44 in conjunction with an "Auto" 
High. The counter output are inverted by Z40B, Z40C, Z40D, Z40E and fed 
into comparator Z54 into which the binary coded digital settings or 
outputs of the "Index Number Switch" 74 are fed from FIG. 2 to terminals 
(B23) . . . (B30), FIG. 11, such that when the comparator detects a number 
of forward carriage passes equal to the setting of the digital switch the 
"Count Out" signal appears at 154 to terminate the cycle. 
The "Load Remind" Output 153 (FIG. 17-C) will automatically inhibit the 
loading operation following a manual operation of the load plunger on the 
assumption that the chuck has been loaded manually, whereby to prevent 
wasting the loaded work piece. 
MODIFIED SWING-HEAD EMBODIMENT 
The form of the machine depicted in FIGS. 19 through 22 extends the 
capabilities of the basic machine heretofore described by providing an 
automatically shiftable or swinging tool head 12X, FIG. 19, in place of 
the manually-set head 12 previously described, with the further inclusion 
of pneumatic cylinder means and supplemental logic programming the swing 
head for automatic cross-cutting, spiral-relieving, and other operations, 
including particularly reverse spiral fluting, in accordance with which 
the grinding wheel 13X is required to shift left or right to pre-selected 
opposite cutting positons crosswise of the axis of the spindle and work. 
In view of the substantial identity of the basic machine components and 
functional control aspects common to both forms of the machine, 
descriptive details of similar and counter part elements and circuitry are 
not repeated in the following description of the modified embodiment, 
identical or essentially analogous components being identified, instead, 
where appropriate, by the same reference numerals used in describing the 
basic machine but further distinguished by addition thereto of the suffix 
--X--. 
In accordance with the block diagram of FIG. 24, the swing-head embodiment 
employes the essential machine structure and control features heretofore 
described, and substantially identical duty-cycle programming logic 
governing the basic machine operations under control of substantially the 
same limit and manual step by step switch means but augmented by 
supplemental logic and supervisory switch means to implement the 
swing-head cross-cutting operations, as will further appear. 
The motors MX-1, MX-2 in FIG. 24 are of a type operating at higher power 
and speed levels to meet the heavier torque and added fluting time 
required for swing-head capabilities, but are likewise activated by 
digitally-set binary pulses in a master and slave servo relationship, as 
will more fully appear. 
Referring to the front view of the modified machine, depicted in FIG. 19, 
the swinging tool head 12X and its grinding wheel 13X and motor 14X are 
mounted as a unit on a swing table 300 which lies behind an end block 301 
(see also FIG. 20) fixed on a cross slide 302 shiftable laterally of the 
spindle axis responsive to turning of the usual cross-feed screw by 
handwheel 304. 
Fixed in a cylinder block 305 secured to the carriage slide below said end 
block are right- and left-table-driving air cylinders 307A and 307B, each 
fitted with brackets carrying a pair of parallel outrigger rods 308A, 
308B, respectively supporting corresponding table limit switches 309A, 
309B on opposite brackets 310A, 310B, which are positionable along said 
rods, and which carry appertaining adjustable spring-cushioned stop 
buffers 311A, 311B, engageable by the corresponding coupling clamps 312A, 
312B of the cylinder plungers on arrival at the selected outer limits of 
travel as determined by setting of the corresponding limit switches. Each 
spring stop or buffer is equipped with a fine adjustment screw 313A, 313B 
to position the same for precise actuation of the limit switches. 
The respective plunger coupling clamps 312A, 312B are attached to a 
corresponding end of a long linear gear rack 316 slideably seated in the 
fixed table block 301 in driving mesh with a confronting segment gear 318 
(FIG. 20 also) seated in the rounded and recessed lower front end portion 
of the swing table such that reverse displacements of the linear gear 
rack, responsive to corresponding activation of the table air cylinders, 
will swing the table correspondingly to the right or left of its central 
zero or "No Angle" position about its pivot 319 on the cross carriage 
slide. 
As in FIG. 20, an arcuate T-slot 320 is provided in the fixed end block to 
seat small adjustable right- and left-table stops 321 which can be set to 
limit the range of table excursions in correspondence with the setting of 
the right- and left-table limit switch assemblies 309A, 309B. 
Each coupling clamp on the linear gear rack is fitted with an offset 
switch-actuating tappet finger 315A, 315B, aligned with the actuating 
plunger of the corresponding limit switch to operate the latter on 
approach of the corresponding air-cylinder plunger to the set outer limit 
of its travel. 
As viewed in FIGS. 20 and 21, the swing table comprises an elongated heavy 
plate 300 turning about pivot 319 fixed in the cross slide, there being an 
offset roller means 324 in the form of a ball-bearing or like 
anti-friction roller affixed at one rearward side of the swing table to 
roll upon a machined glide plate 325 fitted onto the carriage slide, and 
also rolling in extended travel upon an arcuate glide wing 326 pivotally 
mounted as at 327 on one of the sides at the rear of the carriage slide 
and having adjustable support at its opposite forward terminus upon the 
end of an adjusting screw 328 threaded into a bracket 329 also attached to 
the slide, whereby the glide wing can be levelled relative to the glide 
plate, such arrangement affording an increased range of travel for the 
table to the extent of 45.degree. in either direction from the centered 
"No-Angle" position. 
The grinding head 12X, as seen in FIGS. 20 and 21, comprises the large 
wheel motor 14X having an elongated cylindrical shaft throat 14XY clamped 
between heavy upper and lower yoke blocks 330 slideably seated for 
vertical movement between upright slideway plates 331, secured to the 
table by gussets 332, and supporting at their upper reaches a pneumatic 
head cylinder 83X, the plunger of which is pivotally connected as at 333 
to the upper yoke block, there being an upper-limit head switch 335 (FIG. 
20) adjustably positioned above the motor body for operative engagement by 
the latter on movement of the motor into the uppermost permitted position. 
Means for automatically modifying the depth of cut of the grinding wheel 
for certain types of work, for example in forming routers and the like, 
comprises (FIGS. 20, 21) a laterally-shiftable gauge bar 337 slideably 
seated in slot means at the rear of the slideway uprights, and urged into 
a normal position by spring 338 to thrust one of the bar ends 337A into a 
normal triggering position beyond the slideway for triggering engagement 
with an adjustably-positionable trigger roller 339 (FIG. 21) carried on 
post means 340 on the machine base and engaged by the bar end when the 
table swings to its limiting position in that direction, whereby the gauge 
bar is shifted toward the left oppositely against an adjustable stop pin 
341 to displace an adjustable drop screw 342 which determines the descent 
and cut of the wheel. 
Threaded into the gauge bar (FIG. 20) is an adjustable drop screw 342 
engaging the underside of the motor body in the normal position of the 
gauge bar to elevate the motor, and therefore the grinding wheel, by a 
slight amount in the order of a few ten-thousandths-of-an-inch, such that 
when the bar is shifted, on striking the stationary trigger roller 339 
mounted on the machine base, the resulting displacement of the drop screw 
from beneath the motor will cause the latter and therefore the grinding 
wheel to descend by the pre-set fractional amount, thereby automatically 
increasing the depth of the wheel cut slightly as a function of swinging 
of the head in one direction. This depth of cut control means is intended 
for use in making cross-cut tools which may require a deeper cut in one 
direction than in the other. As will appear hereafter, still another 
depth-of-cut means is provided for operation in both the right and left 
spiral leads and requires repeating the carriage passes a number of times 
in both directions in accordance with the setting of a digital switch for 
such purposes. 
The tool head may be adjusted up or down in setting the grinding wheel for 
the primary depth of cut by turning the ball handles 343 of a long 
vertical head screw 344 working in tube 345 bracketed to the slideway by 
plate 346, with the lower exposed end 344A of the screw bearing upon a 
hardened wear plate (not seen) on the top of the glide roller bracket 324, 
there being a lateral extension 330A from the lower yoke block upon which 
the lower end of the screw tube is seated, and the screw itself threading 
into said block extension so as to thrust its said end against the roller 
and thereby force the yoke assembly up or down as the screw is turned for 
the purpose of pre-setting the working elevation of the wheel for 
depth-of-cut and diameter of the work piece. 
The head will also be raised or lowered relative to the work by its air 
cylinder 83X which can be activated manually at the machine by operation 
of a head cylinder air solenoid switch 348 seen in FIG. 20 but omitted for 
clarity from FIG. 19, this pneumatic cylinder being also operable in 
automatic duty cycling to be described. 
The descent of the head assembly to engage the wheel with the work is 
buffered and stopped by engagement of the underside of the underside of 
the bracket plate 346 with the plunger of a dashpot 347 adjustably 
attached to the slideway structure, FIG. 20. 
Thus, the swing-head assembly 12X comprising the grinding wheel 13X, motor 
14X, air cylinder and table-pivoting gear means 307, 316, 318, 321, and 
head cylinder 83X and the associated adjustment and control appendages 
309, 311 carried with the swing table 300 and cross slide 302, can be 
turned automatically as much as 45.degree. to the right or left of a 
"No-Angle" centered position in which the plane of the grinding wheel 
would be parallel with the axis of the work piece, as in cutting straight 
flutes, to any pre-selected angular position crosswise of that axis, as 
determined by the setting of stops 321 for engagement by the table index 
stop 322, as in grinding right or left cross cuts, spiral fluting, and 
relieving, and various other abrading operations. 
In other respects, the modified structural form of the machine shown in 
FIGS. 19 through 25, particularly, is substantially the same and may 
employ substantially the same step-by-step and duty-cycle logic for the 
basic machine functions in conjunction with supplemental logic required by 
the swinghead modifications and represented by inclusion of an added logic 
card L-3 in the block diagram of FIG. 24, and specifically illustrated in 
the subcircuits detailed in the modified logic of FIGS. 26-A to 26-C, 
along with the modified motor-drive and control logic and Indexing 
subcircuits of FIGS. 28-A through 31. 
The automatic cross-cutting functions can also be utilized in dressing, 
relieving, and backing-off operations on flutes which are already cut and 
which may be of either right- or left-hand lead, but since such pre-fluted 
drills will fall from the magazine into the loading plunger seat in 
haphazard angular attitudes, it becomes necessary to turn them into proper 
starting position immediately after the chuck closes and before the 
spindle starts to rotate, and for such purposes a supplemental 
spindle-orienting means is provided in the form of a small electric motor 
350 driving the work spindle through clutch means 351 under control of 
manual switch means 349, FIG. 19, and including mechanism (not shown) 
operative to stop the motor when the pre-fluting is in proper starting 
position for engagement by the grinding wheel. 
A significantly increased working load is imposed upon the carriage and 
spindle motors by the swing head operations, which commonly involve larger 
sizes of drills, routers, reamers and the like, with the result that these 
motors must work at considerably higher current levels in the order of 10 
amperes, by reason of which motors M-1, M-2 are replaced by high current 
printed-circuit type motors MX-1, MX-2 capable of working in a servo mode 
at higher shaft speeds without losing synchronism, so that they can 
maintain the pre-set carriage and spindle speed ratios under control of 
digitally-set binary coded drive pulses as in the case of the motors M-1, 
M-2. 
MODIFIED SWING HEAD CONTROL AND DRIVE MEANS 
As indicated by similar reference numerals distinguished by the suffix 
--X--, FIG. 22 substantially duplicates the schematic plan of the basic 
machine components, limit switches, air cylinders, and connection 
terminals, such as are shown in FIG. 2, but is modified by replacement of 
the manually-set grinding head 12 by the swing head 12X and appertaining 
limit switches and air cylinders, along with use of the high-torque, 
high-speed printed-circuit motors MX-1, MX-2 in substitution for the 
wire-wound motors M-1, M-2 of FIG. 2, with appropriate cable terminals for 
interconnection with the duty cycle and motor drive subcircuits in the 
control unit 70X. 
The modified control unit 70X shown in FIG. 23 includes all of the manual 
controls or their substantial equivalents found on the panel of the unit 
70 shown in FIG. 7 to the extent indicated by similar reference characters 
designated by the suffix --X--, to which controls are further added on the 
modified control panel a toggle switch 353 designated "Auto Load" to make 
automatic loading of the blanks optional for set-up purposes, together 
with an "On/Off" switch 359A associated with a newly-added thumbwheel 
switch 359 operative to set the number of "Reverse Flutes" required to be 
ground in a given duty cycle. 
The two previously-described table-to-spindle speed ratio switches 71, 72, 
for the helix or lead angle, found on panel 70 of FIG. 7, are replaced on 
the panel of unit 70X by the "single-entry" thumbwheel switch 354 
designated by the legand "Lead 1/N," by which this speed ratio can be set 
more conveniently with entry of only the denominator value "N," since the 
carriage speed is adjusted to a relatively fixed standard rate in this 
embodiment to service as a "Velocity Reference" speed, as explained more 
fully hereafter. Further, the indexing control 73 previously designated in 
FIG. 7 as the "Index Distance" switch, is replaced in FIG. 23 by the 
thumbwheel switch 355 analogously designated "Index Pulses" which is 
determinative of the identical index-distance parameter set by digital 
switch 73 in the embodiment of FIG. 7. 
Switch 356, designated "Reverse Index Pulses," sets the index distance 
pulses needed for the reverse flutes, the number of which will be 
predetermined by the setting of the "Reverse Flutes" switch 359 (when 
enable by switch 359A), while digital switch 358 determines the number of 
regular (e.g. right-hand) flutes. If deeper fluting cuts are required, the 
carriage passes may be repeated the number of times set on the "Flute 
Passes" switch 357. 
By reason of the fact that the modified machine also performs all of the 
grinding operations of which the basic machine is capable, the substantial 
part of the operating and duty-cycle logic for the latter, as represented 
by the logic cards L-1, L-2 of FIG. 8, and the corresponding detailed 
logic subcircuits of FIGS. 16A through 18, may be utilized in the modified 
control unit 70X of FIGS. 23 and 24 in accompaniment with added logic 
represented by logic card L-3, which provide general supplemental control 
for the swing-head functions, in accordance with the subcircuitry of FIGS. 
26A through 31. 
Referring to the block diagram of FIG. 24, the substituted motors MX-1, 
MX-2, are of a known variety, having flat, commutator-fed printed-circuit 
type "Armatures" rotating in a strong permanent-magnet field (not 
illustrated) at high power levels, these motors being driven by 
digitally-set binary actuating pulses in a servo mode for which purposes 
each motor has in driving association therewith a correspondingly 
designated tachometer-generator and an optical encoding means of known 
character, together with respective solid-state amplifying means 
comprising a part of each motor unit and therefore embraced within 
respective broken-line enclosures designated 30X and 40X to identify the 
complete individual motor units in a form in which they are obtainable 
commercially. 
Continuing in view of the block diagram of FIG. 24, the carriage motor MX-1 
will be energized on closure of the panel switch 352 by respectively 
positive or negative speed-control voltage for clockwise or 
counterclockwise rotation from speed control potentiometers 79AX or 79BX 
via conductor 361 and power amplifier 362 to the carriage motor of unit 
30X thereby causing the appertaining encoder to apply appropriate forward 
or reverse drive pulses via Decoder 363 and gate 364 to a Frequency 
Divider 365 which produces a resultant binary pulse drive output in 
accordance with the setting of digital switch 354 acting thereon via 
conductor 360 with the resultant binary-coded output applied in turn via 
conductor 366 to an Up-Down Counter 367, the output of which is converted 
to corresponding analogue voltages by a digital to analogue converter 368 
and applied to motor MX-2 via Power Amplifier 369, biased by the MX-2 
tachometer output via conductor 371. 
Forward and Reverse direction and drive of the spindle motor is regulated 
by the MX-1 tachometer-encoder, directional Flip Flop 372, and an 
associated Decoder 363 applying via OR gate 364 an input to Frequency 
Divider 365 governed by the setting of the binary-coded digital ratio 
switch 354 via conductor 360 to provide a resultant driving output applied 
via conductor 366 as one input to an Up-Down Counter 367, along with 
directional signals from the Flip Flop via conductor 373, with Reverse and 
Forward Regulating Pulses from the appertaining encoder applied as further 
inputs to the Up-Down Counter to produce proportionately varied driving 
voltage to the motor as aforesaid, whereby the position of the spindle is 
maintained at all times precisely in step with the carriage motor at the 
set ratio 1/N. The nominal or reference velocity of the carriage motor, 
represented as the numerator "1" in such ratio, is derived from the 
velocity reference Output 433 of FIG. 28-B and may be set by the 
potentiometer 79AX at about 4,000 driving pulses per minute and will 
normally remain at this value indefinitely unless adjusted for special 
jobs or compensation for drift or other ambient conditions, so that entry 
of only the denominator digits "N" into thumbwheel switch 354 will be 
required usually to change the lead angle. 
As in the case of the first-described embodiment, the reverse travel of the 
carriage is set by potentiometer 79BX to produce a faster homing speed in 
reverse direction to economize time in the indexing operations and speed 
up the production rate of such machines. 
MODIFIED LIMIT AND MANUAL SWITCH MEANS 
The circuit connections from the limit and manual control switches and air 
cylinders of the basic machine, which are extended to the control unit 70 
according to FIGS. 2 and 9, together with a substantial part of the 
control logic heretofore detailed in FIGS. 16-A through 17-F, are also 
utilized in the swing head embodiment and reappear (identified by 
suffix-X- reference characters where necessary) in the modified 
counterpart control switch diagrams of FIGS. 22 and 25 in conjunction with 
the newly-added supplemental limit switches and manual switches and air 
cylinder means for the grinding head and its swing table, including 
specifically a head limit switch 335 signalling the raised or "Head Up" 
condition of the grinding wheel as a condition precedent to permitting any 
change in the angle of the swing table, and providing a "Head Up" High 
output at terminal 336 in FIG. 25. 
Swing table limit switches 309A, 309B, designated "Angle Left" and "Angle 
Right" in FIG. 25, are connected in series such that when both are closed 
a "No Angle" signal is produced at output 370 indicating that the table is 
locked at some position between its limits and therefore can be permitted 
to move responsive to a move signal. 
Control of actuating air to the two swing table cylinders is provided 
responsive to "Swing Signals" from the logic cards at one or the other 
inputs 334 respectively resulting in a "Solenoid Position -1" High Output 
314, or a "Solenoid Position -2" High Output 317, FIG. 25. 
Since the control switch arrangements of FIGS. 2 and 9 are substantially 
duplicated in FIGS. 22 and 25, and the duty-cycle logic of FIGS. 16-A 
through 17-F is but slightly modified for the swinghead operations, only 
the needed supplemental duty-cycle logic changes made in FIGS. 16-A, 16-E 
and 17-C will be described in detail hereafter, as shown in the modified 
counterparts thereof depicted in FIGS. 26-A, 26-B and 26-C, it being 
observed that the modified motor-drive and speed regulation logic for the 
substituted printed-circuit motors is to be separately described 
hereafter. 
SUPPLEMENTAL LOGIC SUBCIRCUITS 
FIG. 26-A duplicates FIG. 16-A and adds thereto two gates 375 and 376 
governed by the newly added "No Angle" and "Head Up" signals in bracketed 
inputs 377 to provide the previously-described outputs at terminals 
(A11X), (A12X) and 116X. No changes are necessary in the previously 
described companion subcircuits FIGS. 16-B, 16-C or 16-D. 
FIG. 26-B substantially duplicates FIG. 16-E but includes an additional 
gate 378 in the control of the steady rest and chuck output 128X for use 
with the optional "Auto" Loading switch 353, and requires supervisory 
inputs from the "No Auto Load" switch Low and the "Chuck Open" Push Button 
Low signal and the "Load Remind" Low signal, with an extension via 
conductor 147 into the circuit of FIG. 16-F to connect with conductor 179E 
therein. 
FIG 26-C is a modification of FIG. 17-C to the extent that it substitutes 
an AND Gate 391 for the inverter Z53B of the latter Figure in order to 
incorporate the newly-added "No Angle" control signal for the swing table 
limit switches to assure that the head does not go down while the table is 
in motion. If both of the table limit switches 309A, 309B are open (FIG. 
25), the table is either in motion or can be permitted to move; but if one 
of these switches is closed and the other open, the table is locked in 
some swing position and can only be moved back in the direction opposite 
and the wheel will not be permitted by the logic to go down until the 
state of the table is confirmed by the "No Angle" supervisory signals. 
In order to permit use of the machine for thread cutting, it may be 
desirable to inhibit automatic part loading, for which purposes the newly 
added "Auto Load" supervisory panel switch 353 in OFF position provides at 
logic circuit board terminals 394 designated "No Auto" -L-, in conjunction 
with the "Cycle Start" Push Button signal via gate 392 and a "Loaded" High 
signal on gate 393, produces the "X-Loaded" High output 395, indicating 
special loading which will eliminate automatic loading in that cycle. 
FIG. 27 shows partially new subcircuitry operative in determining the 
number of times the carriage passes will be repeated to obtain deeper 
cuts, according to the setting of the thumbwheel switch 357, and also the 
number of flutes which will be cut according to the setting of thumbwheel 
switch 358. 
The pass counting means shown at the left of FIG. 27 comprises a comparator 
380 providing the "Count-Out" output 154X as the result of matching the 
bracketed inputs 383 from thumbwheel switch 357 and the output of Decade 
Counter 381 clocked under control of gate 382 from Strobe Flip Flop 405 
and a directional NOR gate 384 governed by inputs "Rev. Flute On Sw." and 
output signals on conductor 385 controlled by directional Flip Flops 386, 
387 and 388. 
Decade Counter 381 is set via conductor 389 under control of logic inputs 
"Auto" High and "Done" High, it being observed that this pass counting 
means is essentially the same as that described in view of FIG. 18. 
The "Rev." High logic input clocks Flip Flop 386 to produce the control 
output 399 designated "Direction 2" Low constituting the companion 
rotational controls for the spindle along with the "Direction -1-" signal. 
Two further directional outputs 410 and 411 for the swing table driving 
solenoids respectively designated "Sol. Posn. 2" High and "Sol.Posn.1" 
High, are provided from the Q and inverted Q outputs of Flip Flop 387 
dependently as shown upon the supervisory control of the designated inputs 
from the bracketed logic and switch inputs 390 including "Man'L", "Reverse 
Flute On L", "Cyc. On Sw.," "Chk. Op.H," and "No Auto Sw. L," together 
with Angle Right and Angle Left signals via the normally closed series 
swing table limit switches 309A, 309B to the clearing inputs of Flip Flops 
386, 387, and signals from the Multiplexer -MUX- (to be described in view 
of FIG. 30 hereafter) via conductor 377 to provide setting and clearing 
signals for Flip Flops 386, 387. 
Bracketed inputs 401 (MSD) and 402 (LSD), respectively representative of 
the most and least significant digits from the flute counting thumbwheel 
switch 358 to Comparators 400 and 403, when matched by the corresponding 
Decade Counters 400A and 403A under clocking pulses from Strobe Flip Flop 
405 via conductors 383A and 383C, provide the outputs on Conductor 406 to 
enable AND Gate 407 gating the Strobe pulses for said counters, as well as 
for counter 381 and for Flip Flop 388. 
DECODER AND VELOCITY REFERENCE SUBCIRCUITS 
FIG. 28-A details the subcircuit by which the direction of rotation of the 
servo spindle motor is governed. The encoders referred to under FIG. 24 
are of a known type (not illustrated) wherein an apertured light disc 
rotates with the motor shafting and has two concentric rings of light 
apertures which are angularly out of phase with each other and through 
which appertaining photocells are activated to produce pulses which, in 
the forward direction of rotation conform to a sine wave function, while 
the pulses in the reverse direction conform to the cosine function. 
The decoder 363 (FIG. 24) discriminates by the phase difference which way 
the shaft of Motor MX-1 is rotating, and the directional Flip Flop 372 
accordingly provides a reversing control signal for the Up-Down Counter 
367. 
As shown in FIG. 28-A, the Decoder comprises a set of three Flip Flops 416, 
417 and 418 which may be of the 7474 dual-D, edge-triggered type, 
connected in an array such as shown with a type 555 timer for delay. The 
respective sine and cosine pulses from the MX-1 Encoder are applied at 
input terminals 419A, 419B via Schmitt Triggers 420A, 420B to produce the 
"Up" counting signal via Gate 421 at Output 422 to provide the "Down" 
counting signal via Gate 423 at output 424, for directional and drive 
control of the spindle motor MX-2 via the Up-Down Counter 367. An output 
"High" 425 is provided from Inverter 426 setting and clearing the signal 
on conductor 427. 
FIG. 28-B depicts the Velocity Reference and stabilizing speed control for 
the Carriage Motor MX-1, which is governed by "Reverse" High and "Forward" 
High inputs on conductors 429, 430 respectively activating the 
photo-diodes 431A, 432A of the two corresponding optical isolators 431, 
432 to produce either a Forward or Reverse velocity reference output 433 
on conductor 434 from the respective emitter-collector circuits 431B, 432B 
thereof, the magnitude of which will be governed by the collector-current 
variations effected by the settings of control potentiometers 79AX and 
79BX at the control panel of 70X. 
The foregoing isolating means eliminates circuit noise, and includes a 
further speed and synchronism means stabilizing and preventing creepage of 
the motors in the idle condition by providing a motor-killing "Hold" to 
ground 435 on output 436 through the emitter-collector circuit of a 
transistor 437 rendered conductive under control of a NOR gate 438 
resulting from the absence of any drive signals on input conductors 429, 
430, whereby any floating idle drive input to the master carriage motor 
MX-1, and therefore to the slave motor, will be shunted out. 
SPEED RATIO INTERPOLATOR 
FIG. 29 depicts the subcircuit governing "Forward" and "Reverse" drive, in 
accordance with indexing supervisory signals and setting of the lead of 
helix angle (1/N) thumbwheel switch 354, and produces three outputs 440, 
441, and 442 respectively designated "Slave Step -L-", "R.Step -H-." and 
"Direction -1-L-." 
The "Slave Step" output 440 appears on conductor 440A from AND Gate 444 
which is enabled in part by overflow or carry output on conductor 445 from 
a set of "Adders" 446A to 446E (e.g. Type 82S83) receiving the bracketed 
inputs 447A to 447E corresponding to the outputs from the thumbwheel 
switch 354, each "Adder" having associated therewith a corresponding 
storage latch or memory 448A to 448E providing clocking signals on 
conductor 449 for the slave step pulse generating means, which comprises a 
holding Flip Flop 450 triggering pulse generator 451, the output of which 
provides one of the two enabling inputs to said AND Gate 444 gating the 
"Slave Step" pulses, which are held until the next pulse follows, the 
remaining enabling signal for the gate being derived from the "Blanking," 
"Straight Flute," and "Forward" logic inputs bracketed at 453. 
The "R.Step" output 441 is a bidirectional control signal for reverse 
fluting and derives from sequenced monostable pulse generators 455 and 
456, triggered from the "Up-Down" input signals via conductors 457, 458 
and gate 454, and is to be extended into the "Index" logic at terminal 465 
in FIG. 31. 
The directional output 442 is also derived from the "Up-Down" inputs on 
conductors 457 and 458 setting and clearing a dual Flip Flop 460 (e.g, 
Type 7474), providing on conductor 461 one of two enabling inputs to a 
pair of directional NAND Gates 462A, 462B, controlling a NOR Gate 463 
cooperably with the remaining enabling input via conductor 464 to said 
pair of gates from the "Direction-2-L-" logic input. 
The machine can be quickly readied for straight fluting and abrading simply 
by positioning the swing head in its centered or zero-angle position for 
which purposes, assuming there will be a plurality of such flutes, the 
indexing of "R-Step" operations will be the only rotational movement the 
spindle will take during the duty cycle, so that operation of the 
"Straight Flute" switch 395S, FIG. 23, to the "ON" position, in 
conjunction with the state of the input signals bracketed at 453 in FIG. 
29, will cause the logic to effect indexing spindle rotation while 
inhibiting spiral spindle rotation during the straight flute duty cycle. 
REVERSE FLUTING MULTIPLEXER 
FIG. 30 illustrates a subcircuit which supervises the reversal of fluting 
in accordance with the direction and number of flutes required, and 
comprises a set of four Multiplexers (e.g. Type 8233) 466A to 466D, each 
having two sets of inputs for right- and left-hand flutes including 
"Forward" binary thumbwheel inputs 8-4-2-1 designated 1-IX, together with 
the "Reverse" binary inputs designated 2-IX, to which are applied the most 
and the least significant digits (MSD) and (LSD) respectively, from the 
"Index" -1 and "Reverse Index" -2 thumbwheel switches 355 and 356, to 
produce resultant bracketed outputs 467A to 467D for extension to the 
indicated circuit board terminals, thereby providing bi-directional 
control signals for extension to the corresponding terminals in other 
subcircuits including the "Indexing" logic of FIG. 31, to be described. 
Two additional Multiplexing Blocks 469A, 469B have binary inputs bracketed 
470A, 470B from the "No. Flutes" thumbwheel 358, providing bracketed 
outputs 471A, 471B connecting to the corresponding terminals of the 
comparators in FIG. 27. 
INDEXING LOGIC 
FIG. 31 depicts substantially the identical indexing logic shown in FIG. 
13, as indicated by the suffic -X- reference characters, and differs from 
FIG. 13 only in the elimination of the 7404 type inverters, such as Z9A to 
Z9E and Z12E between the counters and comparators which are used in that 
embodiment to pull up the levels to +5. volts, whereas in FIG. 31 these 
points are tied to ground internally for this purpose. 
The operation of FIG. 31 is otherwise the same as that previously described 
in that the "Index" signal at logic input (A4X) in FIG. 31 likewise clocks 
the Flip Flop Z1X and starts the one-shot timer Z2X to provide the 
blanking signal on conductor 113X appearing at output 114X when the 
"R.Step" input from FIG. 30 is present on conductor 477, to enable the 
gate Z8BX, the output of whch on conductor 478 clocks the "Decade 
Counters" as the result of input on the NOR Gate Z28AX from either the 
"Auto" input A5X or the output on conductor 480 from the timer via gate 
Z8AX. 
Blanking stops the "Up-Down" counting by interrupting the resetting 
operations thereof and starts the counting of the sample pulses from the 
one-shot timer Z2X, and when the comparator count-out is reached the 
count-out gate stops the blanking and the resetting of the counters and 
rotation of the spindle resumes at the preset index distance.