FR2640774A1 - AUTOMATIC CONTROL SYSTEM FOR A MACHINE TOOL FOR MACHINING HELICOIDAL GROOVES - Google Patents

Abstract

The invention relates to an automatic control system of a machine tool for machining helical grooves. According to the invention, the control system comprises a signal former serving to give, to a workpiece, an additional rotation to the position corresponding to the next helical groove to be machined; this former comprises a sensor 19 of the initial angular position of the part, a counter 25 of the number of pulses corresponding to the current value of the angle of rotation of the part, a block 27 determining the value of the additional rotation of the part. part for each helical groove to be machined and a comparator 28. The invention applies in particular to milling, grinding and other types of machining of helical grooves of cutting tools.

Description

The present invention relates to machine tools,

  and more particularly automatic control systems

  than a machine tool for grinding helical grooves

coidales of pieces.

  The invention can be applied to milling machines,

  grinding machines or machine tools for machining grooves

  Helicoidal tooling tips, including in

  chines-tools with programmed control.

  There is an automatic control system for one turn for external threading, which synchronises the feed of the tool with the rotations of the spindle. This lathe comprises a mobile chari.ot driven by a motor, and a doll with a rotating spindle which receives the coin

  to be treated and which is rotated by a motor.

  The program control system of this spinning lathe provides, piece by piece, a helical movement

  the course of the machining by a correlative management of its rota-

  tion and satranslation and comprises a pulse sensor of the number of turns or rotations of the spindle in electrical connection with the servo motor of the transmission. This servo loop contains, in series, a gate, an adjustable pulse counter, an interpolator whose

  signals come through a command block on the

  Vessel (SU, A, 563266). The control system acts to compensate for the tracking error between the rotational frequency of the spindle motor and that of the spindle motor.

  advance when threading to allow the tool to

  take the net in the case of repeated passes This is achieved by the fact that the system has a pulse counter which is connected to a number of turns or

spindle rotation.

  However, this control system is incapable

  to make the spindle make a nearly angular displacement

  written to allow multiple passes of the tool, which is required for the manufacture of drills, reamers, end mills and other end tools. This is because the pulse sensor of the number of turns of the spindle available to the system does not inform on the position of this spindle but only on the frequency

actual rotation.

  There is an automatic control system of a machine tool for machining the helical grooves of a machine.

  end cutting tool (US, A, 4068414). This machine

  carries a movable carriage driven in translation by a stepping motor and a doll with a rotating spindle

  carrying the workpiece and driven by a stepping motor.

  The control system of this machine tool for machining helical grooves, in addition to conferring on the

  piece to be machined a helical movement during the course of

  swims with a prescribed step and distance, allows the

  angular positioning of the spindle with the workpiece

  that the helical grooves to be machined are multiple. The system comprises a pulse generator driving the

  stepper motors, programmers of the length of machining

  of the helical groove, the number of helical grooves

  coxdales and the pitch of the net, each of which is composed of a

  manually operated decade switch and a converter

  binary number-impulsions, and a pulse counter representative of the machining length, a helical groove counter connected to the number of groove programmer, an operating ratio former whose inputs are connected to the output of the counter of representative pulses of the machining length and the outputs of the helical groove counter, the outputs of the former being connected to the first and second stepper motors. The system also includes a signal former that rotates the workpiece to a position

  corresponding to the next helical groove to be treated.

  This system ensures the angular positioning of

  the spindle with the workpiece when it comes to machining

multiple helicoidal nails.

  Positioning is launched at the moment when the opera-

  machining of a groove ends, when the carriage returns b to its starting position, the pulse access to the stepping motor driving the rotating spindle is

  prohibited for a short time and the number of

  sions corresponds to the angular positioning interval. While the carriage continues to move, there comes a time when the spindle, with the workpiece, takes an angular position corresponding to the beginning of the machining of the next helical groove, that is to say

  at the moment when the translation spindle has traveled

  ratio equal to the ratio where is the pitch of the groove n

  helicoidal and n is the number of these grooves.

  This is the moment at which the transmission of the pulses to the stepping motor driving the rotating spindle is resumed, thereby relaunching the helicoidal movement of the workpiece, which continues until

  the initial linear position of the processing

  the subsequent groove o the carriage starts again

his work run.

  The angular positioning method above,

  which is at the base of the control system, presents the incon-

  that the variation of the pitch of the helical groove or of the machining length causes a variation of the reciprocal angular position, of the moment when the machining of the groove in progress and the moment when begins

machining the next groove.

  This leads to a change in the number of

  determining the positioning interval. The opera-

  the machine tool is obliged to use

  pre-established tables with data on the precom-

  position of machining programs of helical grooves

  on each specific piece to be machined.

  The consequence is a waste of time due to

  new machine tool setting and flexibility

  sufficient control of the latter in the case of a

duction in small series.

  One further disadvantage is that the subjection of the positioning interval at the pitch of the helical groove and at the machining length hardly allows positioning in the case where one has. <N, n ' being the machining length of the groove. The object of the invention is to create a control system

  machine tool to eliminate the ef-

  fet of the variation of the parameters of the helical movement of the workpiece on the angular positioning during the machining of helical grooves, thanks to the continuous formation of the additional information on the position of

spindle.

  The problem is solved by the fact that, in an automatic control system of a machine tool for machining helical grooves of a cutting tool, which

  comprises a first stepping motor driving in transla-

  the workpiece, a second drive stepper motor

  rotating the workpiece and ensuring its movement

  coiled with the first motor not to

  not, a programmer of the machining length, a program

  the number of helical grooves, a counter of the number of pulses corresponding to the machining length which is connected to the programmer of the machining length, a helical groove counter connected to the programmer of the number of helical grooves, a trainer of operating regimes whose inputs are connected to the output

  the number of pulses corresponding to the length of the

  machining center and the groove counter

  helical, these outputs being in connection with the first

  first and second stepper motors to put the workpiece into

  in a helical motion, and a signal former

  used to give the workpiece an additional rotation

  to a position corresponding to the next helical groove to be machined, and which is connected to the operating speed former, according to the invention, the signal former serving to give the workpiece a rotation

  to the position corresponding to the reason

  the next machining coil contains a sensor of the initial angular position of the workpiece which is

  attached to the spindle of the machine tool, a counter of the

  number of pulses corresponding to the current value of the rotation angle of the workpiece, whose input

  counting is connected to the second stepping motor through

  of a switch, another switch input being connected to the sensor of the initial angular position, a block determining the additional rotation value

  of the workpiece for each helical groove to be machined

  ner, whose input is connected to the programmer of the number of helical grooves and whose other input is connected to the

  helical groove counter, a comparator of

  signals representative of the current value of the angle of rotation, the inputs of which are connected to the outputs of the counter of the number of pulses, corresponding to the current value of the angle of rotation and to the output of the block

  determining the additional rotation value of the

  this to be machined, these outputs being connected to the operating regime former and to the input of a number counter

  pulses corresponding to the additional rotation angle

  which is linked to the formator

ment.

  It is good that the trainer of working regimes

  It has a circuit for resetting the blocks of the system, which has its input connected to the counter of the number of pulses corresponding to the machining length, a signal shaper of direction of the reciprocal translation movement of the workpiece. to be machined, whose input is connected

  at the exit of the reset circuit, a

  signal of the direction of rotation of the workpiece whose inputs are connected to the output of the reset circuit and the output of the comparator, a circuit forming the stop signal of the workpiece , having

  one of its inputs connected to the output of the counter of the

  number of pulses corresponding to the machining length, its other input being joined at the output of the counter the number of pulses corresponding to the additional rotation angle of the workpiece and its output being connected to the signal former direction of rotation, a controller circuit of the initial angular position of the part

  to be machined, whose input is connected to the sensor of the posi-

  angular t-ion, and a switching device whose inputs are connected to an impulse generator, at the output of the circuit forming the stop signal of the workpiece and the output of the control circuit of the

  initial angular position of the workpiece.

  The comparator may comprise an adder, whose inputs constitute those of the comparator, and a comparison circuit, the inputs of which are connected together.

  two to those of the adder and whose output signal

  This translates the sign of the result of the addition, and the block determines the value of the additional rotations of the workpiece for each helical groove to be formed.

  can be realized around a permanent memory.

  It is also good that the training circuit

  the stop signal of the workpiece contains a latch

  producing it a signal of end of machining which has its entry

  connected to the output of the counter the number of pulses cor-

  corresponding to the machining length and the output of the cir-

  firing, a latch producing a rotation stop signal, which has its inputs connected to the output of the counter of the number of pulses corresponding to the additional rotation angle, to the direct output of the flip-flop producing the end of machining signal and at the output of the reset circuit, a flip-flop producing a tap signal of the original position of the displacement, which has its inputs connected to the direct output the latch producing the stop signal of the rotation

  and at the output of the counter the corresponding number of pulses

  at the additional angle of rotation, an im-

  origin of displacement, which has one of its

  inputs connected to the inverse output of the output flip-flop

  the end of machining signal and its input connected to the counter output of the corresponding number of pulses

  at the machining length, a pulse trainer completes

  angular positioning, the inputs of which are connected to the inverse output of the latch producing the

  end of machining signal and at the output of the counter of the

  number of pulses corresponding to the angle of rotation

  additionally, an OR circuit which has one of its inputs connected to the output of the original displacement pulse former and its other input connected to the output of an inverter and a signal forming signal generator. displacement origin whose inputs are connected to the output of the reset circuit and to the

OU circuit output.

  The invention will be better understood and other purposes, details and advantages thereof will become more apparent in the

  light of the following explanatory description of a

  embodiment given solely by way of non-limiting example, with references to the appended nonlimiting drawings in which: - Figure 1 shows a block diagram of an automatic control system of a machine tool according to the invention; - Figure 2 shows a block diagram of a

  trainer of the operating regimes of the constituent

  the system according to the invention; FIG. 3 shows a circuit for resetting, or initializing, the blocks of the system according to the invention; FIG. 4 shows a circuit for forming the stop signal of the workpiece according to FIG. invention; - Figure 5 shows a signal trainer of the direction of rotation of the workpiece according to the invention; FIG. 6 shows a signal shaper of the direction of movement of the workpiece according to the invention; - Figure 7 shows a controller circuit of the initial angular position of the workpiece, according to the invention; FIG. B shows a switching device according to the invention;

  FIG. 9 shows a comparator according to the invention

tion; and

  - Figure 10 shows a block determining the

  their additional rotations of the workpiece according to

the invention.

  The block diagram of a control system of a machine tool for machining helical grooves as well as the kinematic chain of the machine tool are

shown in Figure 1.

  A frame 1 door, movable on slides 2, a carriage 3 driven by a stepper motor 4 at the feed rate. On the slides 5 of the carriage 3 is installed a doll 6 having a pin 7 which receives a workpiece 8 which is fixed by means of a clamping mechanism 9 in a clamping sleeve 10. The pin 7 is driven in rotation by a stepping motor 11. In the carriage 3 is incorporated a piston control 12 which is coupled to the doll 6. The doll 6, urged by the control 12, moves from its extreme forward position, where the workpiece 8 places its front end on a supporting prism 13,

  at the extreme rear position where the workpiece is

  using a manipulator, not shown on the diagram.

  sin, and vice versa. The information concerning the position of the doll 6 in the machining zone is provided by a limit microswitch 14 which is actuated by a

  stop 15 during the movements of the doll 6.

  The working tool 16 is brought into contact with the workpiece 8 by means of a mechanism 17. The spindle

  7 has a tray 18 with a hole through which he cooperates

  father with a sensor 19 of the initial angular position

of pin 7 carrying piece 8.

  The control system of the machine tool comprises

  a programmer 20 of the machining length, a pro-

  grammar 21 of the number of helical grooves, a

  22 of the number of pulses corresponding to the machining length, a helical groove counter 23, a

  operating regimes 24 and a trainer of

  general purpose to give, to the workpiece, an additional rotation to a position corresponding to the start of the machining of the next helical groove. This signal former serves to provide additional rotation to the workpiece, contains an angular position sensor

  initial 19, a counter 25 of the number of impulses corresponding to

  spanning at the current value of the rotation angle of the spindle 7 with the workpiece 8 to be machined during machining, a switch 26, a block 27 determining the value of the additional rotation of the workpiece for each groove following, a comparator 28 of the signal representative of the current value of the rotation angle of the spindle 7 to the signal representative of the value of the rotation angle of the spindle 7 corresponding to the start of the machining of the next groove of which the information lies in block 27, and

  a counter 29 of the number of pulses corresponding to the year

  additional rotation of the workpiece resulting from

  comparison by means of comparator 28. The system

  The control system also comprises a treatment step former 30, dividers 31 and 32, dispensers

  33 and 34 and amplifiers 35 and 36 ensuring the syner-

  programmed programming of the stepper motors 4 and 11 during the formation of the helical movement of the workpiece 8. The outputs of the controllers 20 and 21 are connected

  information inputs 37 and 38 of the counters

  22 and 23. The windings of stepper motors 4 and 11 are connected to the outputs of amplifiers 35 and 36.

  whose inputs 39 and 40 are connected to the outputs of the dis-

  tributeurs 33 and 34 whose inputs 41 and 42 are connected to the outputs of dividers 31 and 32 and whose inputs 43 and 44

  are connected to the sign exits of the trainer 24.

  The dividers 31 and 32 whose inputs 45 and 46 are connected to the pulse code outputs of the former 24 have inputs 47 and 48 which are connected to the outputs of the formant 30. The pulse code output of the divider 31 is connected , moreover, at the pulse input 49 of the switch 26, the pulse code output of the

  divider 32 being connected to the impulse input 50 of the compu-

  22. The other input 51 of the switch 26 and the reset input 52 of the counter 22 are connected to the outputs of the former 24, the output of the counter 22 being

  connected to the input 53 of the former 24. The sensor 19 is connected to

  corded to an input 54 of the former 24 and to the reset input 55 of the counter 25, the pulse input 56 of which is connected to the output of the switch 26 and whose information outputs are connected to the information inputs 57 of the comparator 28 whose sign output is connected to an input 58 of the trainer 24 and whose information outputs

  are connected to the information inputs 59 of the counter 29.

  The input 60 for resetting the counter 29 is connected to the output of the former 24, its counting input 61 is connected to the switch 26 and its output is connected to

an inlet 62 of the former 24.

  The block 27, whose information inputs 63 and 64 are connected to the outputs of the programmer 21 and the

  counter 23, has its outputs connected to

  comparator 28. The counter 23 has a

  count 66 and a reset input

  tial 67, which are connected to the outputs of the trainer 24 and it

  is connected by its output to the input 68 of a communication element

  69 of the mechanism 17. The microswitch 14 is connected

at an inlet 70 of the former 24.

  The schematic diagram of the trainer 24 of the regimes of

  operation is given in Figure 2.

  The shaper 24 comprises a working pulse generator 71 which drives the stepper motors 4 and 11 of FIG. 1, a circuit 72 for resetting the

  blocks of the system, which can be seen in Figure 2, a

  73 of the signal of the direction of rotation of the workpiece which provides the sign of the rotation of the stepper motor 4 or the stepper motor 11, a trainer 74 of the singal direction of displacement that can be seen at FIG. 2, giving the sign of the direction of rotation of the motor 4, a circuit 75 of

  forming of the stop signal of the workpiece, a cir-

  fired 76 which controls the initial angular position of the workpiece and elaborates the setting signal, by the workpiece

  to be machined, from the initial angular position according to the posi-

  plate 18 with respect to the sensor 19 and a device

  switching device 77 for starting or stopping the motors 4 and 11 according to the

command.

  The generator 71 of FIG. 2 is connected to the pulse input 78 of the switching device 77 and to the pulse input 79 of the controller circuit 76 which is provided with an input 54 from the sensor 19, an input 80 connected to the output of the circuit 72 and outputs,

  which are connected to inputs 81 and 82 of the

  mutation 77, an entry 70 comes from the microswitch

  14 and entries 83 and 84 are connected to the outputs of the

cooked 75.

  The device 77 has its outputs connected to the diodes.

  viewers 31 and 32. The circuit 72 is provided with an input 53 which is connected to the output of the counter 22, an input which is connected to the microswitch 14, inputs 86 and 87 which are connected to the outputs of the circuit 75, and its outputs are connected to the input 60 of the counter 29, at the input 88

  of the former 74 and at the entrance 89 of the circuit 75.

  The forming circuit 74 has an input 90 representing the input of the forming block 24 and which is connected to the counter 22, its outputs being connected to the distributor 34 and to the counter 23; the forming circuit 73 has its input 58 connected to the

  distributor 28 and its output connected to the distributor 33.

  The inlet 91 of the former 73 is connected to the exit of the cir-

  bake 75, whose input 62 is connected to the output of the

  29 and whose output is connected to the switch 26.

  The structure of the circuit 72 is shown in FIG. 3. The circuit 72 comprises a signal former 92 which is connected to the microswitch 14 and the output of which is connected.

  at the input 93 of an OR circuit 94, at the input 95 of a circuit

  fired OR 96 and counter 23. The former 92 produces a brief pulse from the side of the signal supplied at its input 85 by the microswitch 14, which comes on the input

  93 of circuit OR 94 whose other input is connected to the

  22 and whose output is connected to the reset input

  in the initial state 52 of the counter 22.

  The OR circuit 94 is used to reset the counter 22 at the beginning of the machining, on a brief pulse at its input 93 which arrives at the input of this counter and after each workpass, on a signal delivered by

  counter 22, after counting the given number of pulses

  corresponding to the prescribed length of machining.

  The OR circuit 96, which is connected to the stop circuit, has its output connected to the input 89 of this circuit 75. It serves to trigger the flip-flops of the circuit 75 on a short circuit.

  pulse at the input 95, at the beginning of the machining, that is,

  say during the presentation of the workpiece in the machining area, which is indicated by the microswitch 14, as well as throughout the machining of the workpiece,

  after each work pass, on a signal sent to the

89 through circuit 75.

  A pulse former 97, shown in FIG.

  is connected to the circuit 75 of FIG.

  linked to the counter 29. It is used to produce a short pulse from the side of a signal coming from its input 87, of the circuit 75, and to apply it to the reset input.

initial counter 29.

  The structure of the signal formation circuit 75

  to stop the workpiece is given in Figure 4.

  The circuit 75 comprises a flip-flop 98 supplying a signal for the end of machining of a helical groove, a flip-flop 99 supplying a stop-rotation signal as soon as the workpiece 8 takes the machining position of a subsequent groove a flip-flop 100 providing a signal

  taken from the original position of movement, the bas-

  101 and 102 and a pulse trainer 103 of origin

  of displacement, an inverter 104, a pulse shaper 105

  angular positioning completion, a trainer

  106 of the take signal from the home position of the move

and an OR circuit 107.

  The latch 9.8, whose input 89 is connected to

  circuit 72 of Figure 2, of which it receives a brief impulse

  3, has an input 108, shown in FIG. 4, which is connected to the counter 22, and an input 109. The outputs of the flip-flop 98 are connected to the circuit 75, to the switch 26

and to the trainer 73.

  Flip-flop 99 has an input 110 which is connected to the output of circuit 72, an input 111 which is connected to the output of labellule 98, an input 112 which is connected to the output of counter 29 and an input 113. The output of FIG. the flip-flop 99 is connected to the input 83 of the device

switching 77.

  Flip-flop 100 has an input 114 connected to the output

  of the flip-flop 99, an input 115 connected to the output of the counter 29 and inputs 116 and 117. The output of the

  flip-flop 100 is connected to the input 84 of the communication device

mutation 77.

  The trainer 103 has an input 118 connected to the output

* 3B of the counter 22, an input 119 connected to the output of the flip-flop 98, its output being connected to the input 117 of the

flip flop 100.

  The inverter 104 has an input 120 connected to the output of the flip-flop 98 and its input 62 is connected to

the output of the counter 29.

  The shaper 105 of FIG. 4 has an input 121 connected to the output of the inverter 104 and an input 122

  connected to the output of the trainer 103.

  Circuit 107 has an input 123 connected to the output

  of the inverter 104 and an input 124 connected to the output

part of the trainer 103.

  The latch 101 has its input 125 connected to the circuit

  107 and its entrance 126 joined at the exit of the circuit 72.

  The "S" and "D" launches of the flip-flop 100 of FIG. 4 are connected to the inputs 109, 113 and 116 of the flip-flops 98,

99 and 100.

  The flip-flop 102 has its input 127 connected to the circuit 72, 128-input is connected to the circuit 107, its input 129 connected to the output of the flip-flop 101 and its input 130

  connected to the output of the trainer 105.

  The shaper 106 has an input 131 which is connected to the output of the circuit 107 and an input 132 connected to the output of the flip-flop 102. The output of the former 106

  is connected to the input of circuit 72.

  The trainer 73 of the direction of rotation signal is

shown in Figure 5.

  It comprises an AND circuit 133, whose input 91 is connected to the output of the circuit 75 and whose input 58 is connected to the output of the comparator 28. The output of the

  circuit 133 is connected to the distributor 33.

  The trainer 74 of the direction of travel signal

is shown in Figure 6.

  It comprises a flip-flop 134 whose input 88 is connected to the output of the circuit 72 and whose input 90 is connected to the output of the counter 22. An output of the flip-flop

  is connected to the distributor 34 and the other to the meter 23.

  The controller 76 of the initial angular position

  of the workpiece is shown schematically in Figure 7.

  It comprises a flip-flop 135 and an AND circuit 136.

  The input 80 of the flip-flop 135 is connected to the output of the circuit 72 and the input 54 is connected to the output of the sensor

19.

  An output of the flip-flop 135 is connected to the input 137 of the circuit 136 and its second output is connected to the input 81 of the switching device 77. The circuit 136 has an input 70 which is connected to the microswitch 14 and an input 79, from the generator 71, the output of the circuit 136 being connected to the input 82 of the switching device

77.

  The scheme of the switching device 77 is

shown in Figure 8.

  This switching device 77 has

  AND circuits 138 and 139 and an OR circuit 140.

  The circuit 138 has an input 141 which is connected to the output of the generator 71 and an input 83 which is connected to the output of the circuit 75; the circuit 139 has an input 142 connected to the generator 71 and an input 84 connected to the output of the circuit 75. The circuit 138 and 139 also have common inputs 70 and 81 which are connected

  at the outputs of the microswitch 14 and the controller circuit 76.

  The output of the circuit 139 of Figure 8 is connected to the divider 32 of Figure 1; the output of the circuit 138 is connected to the input 143 of a circuit 140 which also has an input 82 connected to the output of the controller circuit 76 and an output connected to the divider 31 of the

figure 1.

  The synoptic diagram of the comparator 28 is given

in Figure 9.

  The comparator 28 comprises a decider adder

  which makes the difference between the number of impulses

  sions corresponding to the current angular position of the pin 7 and the one that reflects the angular position of this pin 7 at the moment when the machining of the subsequent groove is initiated, and a circuit 145 for comparing binary numbers, shown in Figure 9, which provides the sign

of the comparison.

  The adder 144 and the circuit 145 have a common input 57 shown in FIG. 1 and connected to the information output of the counter 25 and a common input connected to the information output of the block 27; in addition, the adder 144 of FIG. 9 has its information output which is connected to the information input of the counter 29 and

  the circuit 145 has its output connected to the formor 73.

  Block 27 of Figure 1 determining the value

  additional rotation is shown schematically in FIG.

  The block 27 is designed around a permanent memory 146 whose address portion receives, through its inputs63 and 64, a binary output code of the programmer 21 (Figure 1) and the counter 23. From pre-established tables, the memory 146 develops output data for quantity

  of grooves to be machined and the number of the groove to be machined.

  The automatic control system of the machine-

  tool for machining helicoidal tool grooves

  cut works the following way.

  The operating cycle of the automatic machine tool begins with the workpiece 8 being placed in the clamping sleeve 10 by means of a manipulator (not shown) and by clamping the workpiece 8 into the machine. clamping sleeve 10 by means of the mechanism 9. This being the case, the headstock 6, moved by the piston control 12, is moved into the machining zone where the workpiece 8 is supported by its front end on the prism 13 and

  the working tool 16 is brought into contact with the micro-

  switch 14 using the mechanism 17.

  A signal from the microswitch 14 arrives

  at the inlet 70 of the forming block 24.

  If, in this case, pin 7 is in the angular position

  initial wave and that the hole of the plate 18 is in the optical path of the sensor 19, the input 54 of the formant 24 receives a signal allowing the pulses at the frequency

  to work on a signal at the entrance to

  impulse code code 24 to the pulse inputs

  45 and 46 of the dividers 31 and 32 and thence to the inputs 41 and 42 of the distributors 33 and 34 and thence to the inputs 39 and 40 of the amplifiers 35 and 36 and finally from there to

  windings of stepping motors 4 and 11.

  The combined operation of the stepping motors 4 and 11, controlled by the state of the former 30 and the dividers 31 and 32, rotates the spindle 7 and moves the carriage 3 so that the machining performed by the tool 16 lead to the formation of a helical groove on

the workpiece.

  If pin 7 is not at its angular position

  initial and that the luminous flux of the sensor 19 is

  cepted by the plate 18, the signal is missing at the input 54 and, in this case, at a signal at the input 70, the pulses at the working frequency only arrive at the input 45 of the divider 31. There is in rotation only the stepping motor 11, and it turns until the moment when the hole of the plate 18 receives the luminous flux of the sensor 19 and it is then

  that at the input 54 of the trainer 24 appears a signal of

  authorization. From that moment on, the two engines will

  together to ensure a helical movement

to the workpiece 8.

  The sensor signal 19 also comes to the input

  resetting 55 of the counter 25, for its resetting.

  On a signal at its input 70, the trainer 24 activates

  ve the reset input 52 of the counter 22 which, once initialized, stores the code arriving at its information input 37, the output of the programmer, and determining the number of pulses corresponding to

  the machining length of the groove. These impulses come

  the output of the divider 32 on the input 50 of the

  22 and simultaneously on the motor 4.

  In the same way, on a signal at its input 70, the formatter 24 activates the reset input 67 of the counter 23, to initialize it in order to record the code arriving at its information input. 38, from

of the programmer output 21.

  A code representative of the number of grooves to be machined

  becomes established in the counter 23, which subsequently evolves

by counting.

  Simultaneously with the arrival of pulses on the stepper motor 11, these also come from the

  output of the divider 31 on the impulse input 49 of the com-

18 2640774

  mutator 26 whose input 51 receives the control signals

of the trainer 24.

  The switch 26 transfers the pulses to

  the input 56 of the counter 25. The counter 25 counts the number

  A plurality of pulses have caused the stepper motor 11 to traverse a certain angle from the initial angular position of the workpiece 8. Since each pulse applied to the stepper motor 11 causes it to rotate at a certain angle, for example 1.5, the angular position of the spindle 7 with the workpiece 8 is known at any time. At each complete revolution of the spindle 7, the hole of the plate 18 receives the light flux of the sensor 19 to generate a signal which, applied to the entrance of

  zero 55 of the counter 25, resets it to zero.

  The current angular position binary code of the pin 7 to the information outputs of the counter 25 comes permanently to the input 57 of the comparator 28 whose input 65 receives from the block 27 the angular position code of the pin 7 to which she must be at the start

  the machining of the subsequent groove.

  This code is developed by block 27 as follows. The binary code representative of the significant natural number of the quantity of the helicoidal grooves comes from the output of the programmer 21 on the information input of the counter 23 and simultaneously on the input 63 of the block 27 which establishes the code of the number of pulses by combining the

  code representing the prescribed number of helical grooves

  dales with the code translating the number of machined grooves.

  The binary code pulses corresponding to the combination

  These codes arrive from the exit of block 27 at

the input 65 of the comparator 28.

  The comparator 28 performs a comparison of the current angular position code of the pin 7 with the code

  angular position of this pin 7 at the start of the

  the subsequent groove and the result of the comparison

  reason comes from the information output of the comparator 28 on the information input 59 of the counter 29. The sign

  the comparison is sent by the comparator 28 to the

  train 58 of the former 24. After resetting of the counter 22, which corresponds to the end of the machining of the groove,

  the input 53 of the trainer 24 receives a signal as a result of

  which it delivers a signal at the input 60 of the counter 29. At this signal, the counter 29 records the code of the number of pulses reflecting the result of the comparison, and

  the forming block 24 provides a signal at the input 51 of the com-

  26. The switch 26 prohibits the pulses from accessing the input 56 of the counter 25 and transmits the

  pulses to the input 61 of the counter 29.

  Lelsignal of comparison sign came to the input 58 of the formant block 24 of the comparator output 28 passes

at the inlet 43 of the dispenser 33.

  The stepper motor 11 turns on the side defined by

  the sign of comparison present at the entrance 43 of the distri-

  scorer 33 and the counter 29, which decrements, counts the number of pulses arriving at the motor 11. The resetting of the counter 29 will have the effect of stopping the motor 11 and thus the locking of the pin 7 with the coin to machine 8 at the corresponding angular position

  at the start of the treatment of the next groove.

  The machining of the groove being completed, at the same time

  angular positioning, the carriage 3 with the po-

  6 is returned to its starting position for machining the subsequent helical groove. The reversal of the market

  of the motor 4 to recall the truck is carried out on a

  reset of the counter 22 applied to the input 53 of the formatter 24, whose fixed signal to the counter 22

  number of pulses corresponding to the length of the

  reminder of the carriage 3 with the doll 6; the entrance of

  pulses 50 of the counter 22 receives, from the divider 32, im-

  pulses arriving at the same time to the stepping motor 4 whose rotation changes direction on a signal at the input

44 of the dispenser 34.

  The counter 22 evolves by counting the pulses

  sions, and the counted, it delivers a signal at the entrance

  53 of the trainer 24. If, at about that time, the position

  Finally, this signal reverses the motor 4 to allow the working stroke to the carriage and the machining of the next helical groove begins. If the positioning is still in progress, the motor 4 is ar-

  and is only restarted after completion of the posi-

  angular We thus manage to ensure an inde-

  pendence of the angular positioning time of the bro-

  7 with respect to the return time of the carriage 3 with the

  doll 6 at the starting position.

  The cycle resumes until the end of the treatment of

the last helical groove.

  At this moment, the step motor 4 recalls, in

  empty, the carriage 3, with the doll 6, to the posi-

departure.

  The counter 23 is reset and the signal at its

  zero output is applied to the input 68 of the communication device.

  command 69 of the piston control 12. The doll 6 returns to

  its starting position o the clamping sleeve 10 is des-

  tightened and the workpiece 8 is removed with the aid of

  pulateur; Then, after setting up a new

  piece to be treated, the treatment cycle resumes.

  The trainer 24 of the operating regimes of the

  Figure 1 operates as follows.

  The microswitch 14 provides a signal at the input

  circuit 72 and at the input 70 of the switching device

  77, as can be seen in Figure 2.

  On this signal, the switching device 77 is ready to transfer, to the dividers 31 and 32, the pulses at the working frequency from the generator 71 of Figure 2 to the input 78 of the switching device 77; the circuit 72 produces a brief pulse from the side of the signal emitted by the microswitch 14 of FIG.

  1, which is applied to the receipt input of the account code.

  22 to establish a code corresponding to the length

  machining the helical groove, and another brief im-

  pulse to set the counter 29 to its initial state for the purpose of counting the additional rotational pulses of the workpiece as well as to reset the counter 23

in the initial state.

  The circuit 72 of FIG. 2 furthermore ensures initialization of the circuit elements 74, 75 and 76 by

  the signals applied to their inputs 88, 89 and 80 respectively

  tively. As soon as the prescribed length is processed and

  counter 22 is zero, former 74 intervenes.

  The counter 22 is reset to a signal supplied by the circuit 72 at its input 52, and the direction sign of the displacement is reversed in the former 74 on

  a signal at the input 90 coming on the distributor 34.

  The shaper 73 of FIG. 2 operates on a signal at its inlet 58 which reflects the sign (the direction) of the additional rotation to be performed before the machining of the subsequent groove. This signal leaves the comparator 28. The sign signal has access to the input 43 of the distributor 33 only if the input 91 receives a signal from the circuit 75, which is significant

  the end of machining a groove.

  The circuit 75 produces a signal at the end of the

  at the end of positioning and at the origin of displacement in length, a signal after the completion of the angular positioning as well as the lengthwise machining and a switching signal of the switch 26 of FIG. machining the completed groove, the counter 22 delivers to the input 53 of the circuit 75 a signal on which it provides another signal to the input 87 of the circuit 72 for

  generate a signal whose arrival at the entry 60 of the

  29 causes the code of the number of pulses corresponding to the additional rotation of the workpiece to be recorded, and a signal from switch 26 which allows

  the transfer of the pulses from the counter 25 to the counter 29.

  Positioning finished, entry 62 of the circuit

  counter 29, a signal that generates, at the end of

  part of circuit 75, a signal at entry 83 of the

  switching device 77 which prevents the pulses from the generator 71 from reaching the input 78 of the switching device 77, which leads to the shutdown of the engine 11 of

Figure 1.

  If, at this moment, the carriage 3 is not yet in its starting position, the motor 4 continues to rotate until the counter 22 is reset, then the input

53 of the circuit 75 receives a signal.

  This signal, also applied to the input 90 of the former 74, causes the inversion of the rotation of the motor

  step 4 and the reset of the counter 22, which leads

  motor 4 to provide the trolley 3 with its working stroke.

  vail. On the same signal, the circuit 75 of FIG. 2 delivers a signal to the input 86 of the circuit 72 which supplies

  also a signal at the input 89 of the circuit 75 which makes it

  at the entrance 83 of the device 77 an authorization signal and

  pulses at the working frequency pass from

  71 to the motor 11 of FIG.

  pin 7 in rotation. That's the way the business starts

  swim from the next helical groove.

  If the carriage 3 comes to take the origin of the displacement

  for machining the subsequent groove before the angular positioning of the pin 7 is completed, a reset signal arriving via the same channels generates, at the output of the circuit 75, a signal which comes to the input 84 of the device 77 to close the access of the step motor 4 to the pulses of the generator 71. The displacement of the carriage 3 ceases and the angular positioning of the pin 7 continues until the counter 29 is reset with effect the appearance of a signal at the entrance 62 of the

circuit 75.

  The signal at the output of the circuit 75 arrives at the

  86 of the circuit 72 and thence to the input 89 of the circuit 75. This circuit provides a signal to the input 91 of the trainer 73 which transfers it to the distributor 33 to inform

  the direction of rotation of the stepping motor 11 during the machining

swim the subsequent groove.

  The signal at the input 62 of the circuit 75 generates

  at its output a signal that arrives at the entrance 84 of the

  This signal sets the device 77 to a state allowing the pulses of the generator 71 to pass to the step motor 4. The carriage 3 starts to move and there is

  machining of the subsequent helical groove.

  The controller 76 of FIG. 2 produces an initial angular position signal by the pin 7 with the workpiece 8, at the moment when the hole

  of the plate 18 captures the luminous flux of the sensor 19.

  From this moment, the operation of the two engines

4 and He is associative.

  If the pin 7 is at its initial angular position and the hole of the plate 18 is in the optical path of the photo-sensor 19, a signal appearing at the input 54 of the controller 76 generates, at the input 81 of the device 77 , a signal allowing the pulses of the generator 71 to access the two stepper motors 4 and 11, and the machining of the helical groove begins. Entrance access 82

  device 77 is then forbidden to the pulses of the gen-

71.

  If pin 7 in FIG. 1 is not in its posi-

  At the initial angular angle, the signal is missing at the input 54 of the controller 76 and therefore there is no signal at the input 80 of the device 77, i.e. the pulses are not allowed to pass to the two stepper motors 4 and 11 from the generator 71, through the input 78 of the device 77 but that they have access, through the input 79 of the controller 76 and the input 82 of the device 77, to engine

  step 11 which turns pin 7 as long as

  19 does not transmit an angular positioning signal

initiality of pin 7.

  Circuit 72 for resetting blocks

  of the system works as follows.

  The shaper 92 of FIG. 3 produces, from the leading edge of the signal from microswitch 14 of FIG. 1, a short positive pulse which comes from the

  output of the formor 92, through the circuit OR 94, to the

  reset meter 52 on counter 22. On

  this pulse, the counter 22 registers the code of the name

  number of pulses corresponding to the machining length pro-

from the programmer 20.

  Through the OR circuit 96 of FIG. 3, the same pulse

  arrives at circuit 75 to initialize its elements.

  The same signal comes from inputs 80 and 88

  fired 74 and 76 to initialize them and at the entrance of

  67 of FIG. 1 of the counter 23 which records the code of the number of helical grooves at the exit of the

programmer 21.

  After the machining of each helical groove and the taking of the original position of displacement by the carriage 3, the circuit 94 receives at its input 53 a signal of the zero output of the counter 22 to transfer it to

the input 52 of the counter 22.

  Upon completion of the angular positioning of the pin 7 and the taking of origin by the carriage 3, the input 86 of the circuit 96 receives a signal which passes to the input 89 of the circuit 75 to initialize the flip-flops 98, 99 , 100, 101 and 102 of circuit 75 and prepare the rest of

his elements at work.

  The shaper 97 of FIG. 3 produces, from the leading edge of the signal from the flip-flop 98, serving to form the end-of-groove signal, a short positive pulse which comes from the output of the shaper 97 to the input 60 of the counter 29 to register the code of the number of pulses corresponding to the rotation

  pin 7, putting it to its posi-

  starting angle of treatment of the following groove

from the comparator 28.

  The stop signal formation circuit 75

in the following manner.

  On a signal sent to the input 89 by the output of the circuit 72, which also arrives at the inputs 110, 126 and 127, there is reset of the flip-flops 98, 99 and 102. After the end of the machining the groove and resetting the counter 22 of Figure 1, the entry 108 of

  the flip-flop 98 receives a signal. The rear flank of this

  generate, at the direct output of the flip-flop 98, a low-level signal, which is applied to the input 87 of the circuit 72 to register, at the counter 29, the code

  the number of impulBions reflecting the additional rotation

  7. The signal at the direct output of the flip-flop 98 of FIG. 4 also arrives at the input 111 of the flip-flop 99 to prepare its transition on a signal applied to its input 112. The same signal arrives at the input of the switch 26 that switches. At the inverse output of flip-flop 98 a high level signal appears. This signal, which arrives at the inputs 119 and 120 of the circuits 103 and 104, authorizes them to accept by their inputs 118 and 62, the

  counters 22 and 29. The same signal is

* plicated at entry 91 of trainer 73 who is responsible for the meaning

  Stepper motor rotation 11.

  If the angular positioning of the pin 7 anticipates the original position of the displacement by the carriage 3, the input 112 of the flip-flop 99 receives a signal from the counter 29 which generates, at the output of this flip-flop 99, a signal low level which is applied to the input 83 of the switching device 77 to prohibit, impulses, access to the motor 11. The same signal arrives at the input 115 of the flip-flop 100 without it changing from state, that is, the pulses are allowed to

  access engine 4 on a signal at input 84 of the

Switching device 77.

  The signal at the output of the counter 29 is applied to the input of the circuit 104 which is conditioned beforehand

  by the flip-flop 98 for transmitting this signal to the

  circuit 107 transfers the signal to the input 125 of the flip-flop 101, which generates, on its

  reverse output, a low-level signal that arrives at the

  129 of the flip-flop 102 to prepare it for tilting.

  The signal at the output of the circuit 107 is also

  applied to the input 128 of the flip-flop 102 without changing its state because before the appearance of this signal, its input

129 was at the top level.

  The signal at the output of the circuit 107 is also present at the input 131 of the formatter 106 but does not have access to the input 86 of the circuit 72 because the input 132 of the formatter 106 is at the low level set at reverse output

of the flip-flop 102.

  After the original position taken by the

  by the carriage 3 and the reset of the counter 22, the inverse input 118 of the circuit 103 receives a signal which

  its transfer, already conditioned by the rocker 98, to the

  trea 117 of the flip-flop 100 whose state is confirmed. So,

  the passage of the pulses through the switching device

  77 is not stopped and the 4 engine continues to rotate

but in the other direction.

  The signal at the input 118 of the circuit 103 is also

  applied at the entrance 124 of circuit 107 which transmits

  at the input 125 of the flip-flop 101, to confirm its state, and simultaneously, at the input 126 of the flip-flop 102 to generate at its inverse output a high level signal which arrives at the input 132 of the circuit 106 for that this one

  transfers the signal to the input 86 of the circuit 72 which furnishes

  signal at inputs 89, 110, 127 and 126 of

  98, 99, 102 and 101 to initialize and condition the passage of pulses to the motor 11 through the

  switching device 77 on a signal at its input 83.

  If the taking of the home position of the

  trolley 3 in FIG. 1 anticipates the position

  angle of pin 7, that is to say that the

  Since the counter 22 is zeroed earlier than the counter 29, the counter 22 sends, through the circuit 103, a signal to the input 117 of the flip-flop 100, to generate at its output a low level signal which is applied to the signal. entry 84 of the

  device 77 for closing, at pulses, the access of the

  4. The trolley 3 which comes out of its original position

  to this position. The signal at the input 118 of circuit 103 has the same

  effect as above, and after the end of the

  pin 7, the motor 4 continues to turn

  milling speed of the groove, the resetting of the

  at the end of the angular positioning putting the

driver 4 on the job.

  If the angular positioning of pin 7 and the taking of the original position of displacement by the

  carriage 3 are simultaneous, that is to say that if the

  22 and 29 are reset at the same time, the inputs 122 and 121 of the former 105 are simultaneously etched and the shaper 105 delivers a signal to the input 130 of the flip-flop 102. This generates, at the inverse output of the flip-flop 102, a high level signal which is applied to the input 132 of the former 106 to allow the transmission of the signal from the output of the circuit 107 through the former 106 to the input 86 of the circuit 72 which, after the account, allows pulses to access both motors 4

and 11.

  The inputs 109, 113 and 116 of the flip-flops 98, 110 and 115 are connected through a load resistor 147 to the power source (not shown).

  The operation of the formant 73 of the sense signal

of rotation is as follows.

  When the motor 11 turns in the machining regime,

  the input 91 of the circuit Et 133 receives a low signal ni-

  caliber of the inverse output of flip-flop 98 of circuit 75.

  On this signal, the inverse output of circuit 133

  goes to a high level. At this state of the input 91 of the circuit

  baked 133, the incoming signal applied to its input 58 of the sign output of the comparator 28 can not change the state of the output of the circuit 133 nor consequently,

reverse the rotation of the engine 11.

  Since the machining of the helical groove is complete, the state of the flip-flop 98 of the circuit 75 changes and the input 91 of the circuit 133 receives a high-level signal which enables the signal at the output of the comparator 28 to pass to through the circuit 133 to the distributor 33. This signal

  translates the sign determining the direction of rotation of the bro-

  7 when angular positioning according to the result of the comparison of the current angular position of the

  pin 7 and the angular position of pin 7 to the

purpose of machining a groove.

  The operation of the formant 74 of the sense signal

of the displacement is the following.

  On a signal at the input 88 of the flip-flop 134 coming from the output of the circuit 72, this flip-flop 134

  provides a high-level signal at input 44 of the

  34, to impose on the carriage 3 a displacement in the

  sense of work. At the end of the machining of a helical groove

  coidale, counter 22 resets to zero and delivers to the

  90 of the flip-flop 134 a signal which makes its

  low, producing the reversal of the meaning of

  moving the carriage 3 of FIG. 1 in view of its

  tower. As soon as the carriage 3 has taken its original position

  displacement, the counter 22 resets to zero and the

  cule 134 has, at its output, a high level signal which forces the carriage 3 to change direction of movement for that

of the work race.

  In addition, for a signal at its input 90, the base

  after the machining of the helicoidal groove, it forms a high level signal arriving at the counting input 66 of the counter 23, decrementing a

  unit corresponding to the machined groove.

  The operation of the controller 76 of the position

  The initial angle of the workpiece is as follows.

  If the pin 7 is at its initial angular position, the sensor 19 provides at the input 54 of the rocker

  a signal for its output to go low.

  From the beginning of machining the workpiece, the input of the flip-flop 135 receives a brief pulse from the formor 92 of the circuit 72 which does not change the state at the output of the flip-flop 135; therefore, the input 137 of the circuit 136 is low preventing the pulses at the working frequency from passing through the circuit 136 of Figure 7 to the input 82 of the switching device 77. A signal at

  high level at the inverse output of the flip-flop 134 is

  plicated at the input 81 of the switching device 77 to give access to the pulses of the two motors 4 and 11, the combined operation of which communicates with the workpiece

a helical movement.

  If the pin 7 is not in initial angular position, the sensor 19 does not send a signal to the input 54 of the flip-flop 135, so at the direct output thereof there is a high level signal and at its opposite exit, a

signal at low level.

  As soon as the carriage 3 has taken the original position of its movement, the input 70 of the circuit 136 receives a signal. Since the input 137 of the circuit 136 is at a high level, the pulses at the working frequency are applied by the input 79 of the circuit 136 to the input 82 of the switching device 77 to turn the motor 11 to

  the appearance of a signal at the input 54 of the flip-flop 135.

  The rest of the operation of the controller has been previously described. The switching device 77 of FIG.

works in the following way.

  The doll 6, once in its original position, the

  micro-switch 14 delivers at the inputs 141 and 142 of the

  A signal that prepares the circuits 138 and 139 to transfer the pulses to the working frequency of the generator 71 to the motors 4 and 11. The input 83 receives a circuit signal 75 as soon as the pin 7 has reached the position. angle prescribed at the start of the machining of the helical groove and the inlet 84 receives one as soon as

  the carriage 3 has taken the original position of its

  is lying. At the start of machining the workpiece, if the spindle is not in initial angular position, the input 81 receives, from the controller 76, a signal prohibiting the passage

  pulses at the working frequency through the inputs 78.

  In this case, the motor 11 receives pulses

  at the working frequency through the input 82 of the circuit 140.

  The motor 11 rotates until the intervention of the sensor 19

  whose output signal is applied to inputs 81 of the

  77 allows pulses at the working frequency

  to pass through entrances 78 and forbids entry 82.

  The comparator 28 operates as follows.

  The input 57 of the comparator 28 receives the binary code of current angular position of the pin 7 of the

  counter 25 which is simultaneously applied to the addition-

  neur 144 and 145 number comparison circuit bi-

  ners. The input 65 of the comparator 28 receives, from the block 27,

  the binary code, which is the value of the angular position

  spindle 7 at the start of groove machining

  helicoidal, which is applied simultaneously to the addition-

neur 144 and circuit 145.

  The result of the comparison is elaborated in the addition 144 and enters continuously through the entry 59 in

the counter 29.

  The machining of the finished groove, the code of the result

tat is frozen in 'counter 29.

  The sign of comparison, formed by the circuit 145,

  is applied to the input 58 of the trainer 73.

  Block 27 determining the value of the rotation

  of the workpiece operates in the following manner.

  Block 27 represents a permanent memory which

  receives, at its input 63, the programmer 21, a code bi-

  reflecting a natural number which is the number of grooves

  helicoidal holes, and the input 64 of the block 27 receives, from the counter 23, a binary code representative of the number of

machined grooves.

  The pulse code formed in the permanent memory

  Block 27 represents the combination of these two codes. This pulse code, representing a certain combination of these codes, is applied from the output of the

  block 27 at the input 65 of the comparator 28.

  To better understand the idea of the invention, we can examine the case where it is a question of machining, for example, a

  end mill with four helical grooves.

  In one complete revolution, the stepping motor 11 of

  spindle 7 with the workpiece 8 "acknowledges" 240 pulses each of which is 1.5. The mechanical transmission between this stepping motor 11 and the

  pin 7 represents a reducer having a transmission ratio of

  mission of 20. This means that for the spindle to turn 360, the stepper motor must receive 240 x 20 = 4800

pulses.

  To take the machining position of the second groove, the stepper motor 1il must receive, from its initial position, 4800: 4 = 1200 pulses; to start machining the third groove, 2400 pulses;

  for the fourth groove, 3600 pulses.

  On the program's decade switch

  Mateur 21, the number 4 which is that of the grooves. The

  their binary of this number is applied from the output of the programmer 21 to the information input 38 of the counter 23 and to the address inputs 63 of the block 27, which receives at its

  other address inputs, the counting outputs of the

  23, decremented by one after the treatment of each

  that groove, the binary value of the residue in the counter 23. The combination of these two codes applied to the inputs

  The address of block 27 gives, in binary, the number of impulse

  necessary for spindle 7 to rotate to the angular position to begin machining a

  helical groove, for example, for the angular position

  Starting point for machining the second groove, this number is equal to 1200 pulses. Code at the exits

  block 27 information is applied to the information inputs.

65 of comparator 28.

  The machining of the first helical groove

  mence at the initial position of pin 7, i.e.

  when the hole of the plate 18 is on the path op-

  The output signal of the sensor 19 is applied to the reset input 58 of the counter 25 for resetting it. Subsequently, the number of pulses "acknowledged" by the stepper motor 11, the current angular position of the pin 7, arrives through the switch 26 at the incrementation input 56 of the counter 25 and, at from its information outputs, comes in

  continuous at the information inputs 57 of the comparator 28.

  The code arriving at the input and the code arriving at the input 57 are constantly made up, and the result is sent constantly to the information inputs 59 of the counter 29, the result sign also arriving in permanence, through the trainer 24, at the entrance 51 of the

switch 26.

  During the machining of a helical groove, the

  pin 7 can make several turns and at each turn

  plet, the sensor 19 provides, at the input 55 of the counter 25,

a signal for resetting it.

  The machining of the groove being completed, the positioning input 60 of the counter 29 receives a signal on the

  forcing to record the binary code of the number of

  corresponding to the result of the addition. For example,

  if, at the end of the treatment of the groove, the

  Step-by-step 11 received 1000 pulses, the content of the counter 29 is 1200 - 1000 = 200 with the positive sign and if, 1400 pulses were received, the contents of the counter becomes: 1200 - 1400 = - 200 with -a negative sign. In this way, if at the time of the end of the machining of a helical groove, the number of pulses received by the stepper motor 11 exceeds that required to enable it to take the angular position of departure of the machining the subsequent groove, the signal at the sign output of the comparator 28 changes, causing the signal to change at the sign input 43 of the distributor 33 and the stepper motor 11 will "clear" this number of pulses, that is 200, in the opposite direction. This reduces the time

  positioning. Simultaneously, the entry 51 of the switching

  26 receives a signal on which it prohibits the pulses access to the counter 25 and allows them to access the counter 29 which will evolve by counting. The motor 11 rotates until the reset of the counter 29 which takes place when the pin 7 takes its angular position of

  machining start of the second groove.

  The machining of the second helical groove being completed, the content of the counter 23 decreases by one

  unitized and becomes equal to the binary code of the number of

  corresponding to the number 3 while the binary code

  number 4 arriving at entry 63 of block 27 remains unchanged.

  gen. The combination of these two codes arriving at the address inputs of the block 27 constitutes the binary code of the number of pulses to be sent to the motor so that it drives the pin 7 to the angular position necessary for machining the third helical groove. , that is, the

pulse number equals 2400.

  Subsequently, the angular positioning, when

  machining of all consecutive helical grooves

  it is done in a similar way.

  It should be noted that the angular positioning method according to the invention, on which the system is based

  command, possibly allows to operate a position-

  angle for machining any number

helical grooves.

  The implementation of the angular positioning method which is the basis of the control system according to the invention allows to perform an angular positioning of a workpiece during machining, whatever the parameters (not and length to be machined) of the helical groove to be machined. This offers a considerable gain in the time needed to develop the PLC, which allows it to be used in large-scale production.

as in small series.

  A further advantage to note is the easy and quick way to change the machining parameters of

  the piece, like the pitch of the helical groove, the length

  machining, the number of grooves, which increases the

  technological possibilities of the automatic machine tool.

RE V E ND I C A T I 0 N S

  1. Automatic control system of a machine-

  tool for machining helical grooves for

  cutting heads, of the type comprising a first stepping motor driving in translation the workpiece, a second stepping motor rotating the workpiece and ensuring, to the workpiece, together with the

  first step motor, a helicoidal movement, a

  grammar of the machining length, a programmer of the number of helical grooves to be machined, a counter of the number of pulses corresponding to the machining length which is connected to the programmer of the machining length,

  a helical groove counter linked to the programming

  number of helical grooves, an operating ratio former whose inputs are connected to the output of the counter of the corresponding number of pulses

  the machining length and the outputs of the speed counter.

  spirals, its outputs being in connection with the first and second stepper motors to put the piece

  machined in helicoidal movement, a trainer of the signal

  to give the workpiece an additional rotation

  to a position corresponding to the helical groove

  coldale to be machined next and which is connected to the operating regime former, characterized in that the former

  of the signal used to give the part an additional rotation

  contains a sensor (19) of the initial angular position of the workpiece which is placed on the spindle

  (7) of the machine tool, a counter (25) of the number of pulses

  sions, representative of the current value of the rotation angle of the workpiece, whose counting input is connected to the stepper motor (11) via a switch (26), one of which another input is connected to the sensor (19) of the initial angular position, a block (27) determining the additional rotation value of the workpiece (8) for each helical groove to be machined, an input of which is connected to the programmer (21). ) of the number of helical grooves and whose other input is connected to the counter (23) of helical grooves, a comparator (28) of the signal representative of the current value of the rotation angle whose inputs are connected to the outputs of the counter (25) the number of pulses corresponding to the current value of the angle of rotation

  and at the output of the block (27) determining the rotational value

  additional, its outputs being connected to the formor (24) operating speeds and the input of the counter (29) the number of pulses corresponding to the additional rotation angle of the workpiece that is connected

  to the operating mode former (24).

  2. System according to claim 1, characterized in that the forming block (24) comprises a circuit (72) for resetting the blocks of the system whose input

  is connected to the counter (22) with the corresponding number of pulses.

  spanning at the machining length, a shaper (74) of the direction of the reciprocating translation movement signal of the workpiece whose input is connected to the output of the reset circuit (72), a forming device (73) of the signal of the direction of rotation of the workpiece whose inputs are connected to the output of the reset circuit (72) and to the output of the comparator (28), a circuit (75) forming a stop signal of the workpiece, one of whose inputs is connected to the output of the counter (22) the number of pulses corresponding to the machining length, and the other input is connected at the output of the counter (29) the number of pulses corresponding to the additional rotation angle of the workpiece, its output being connected to the formant (73) of the direction of rotation signal, a controller (76) of the initial angular position of the workpiece whose input is connected to the

  sensor (19) of the initial angular position and a

  positive switching device (77) whose inputs are connected to a pulse generator (71), to the. output of the stop signal forming circuit (75) of the workpiece and the output of the controller (76) of the angular position

initial of the workpiece.

  3. System according to any one of the claims

  1 or 2, characterized in that the comparator (28) comprises an adder (144) whose inputs are the inputs of the comparator (28) and a comparison circuit

  (145), whose entries are two by two

  adder (144) and whose output signal reflects the result sign of the addition;

  4. System according to any one of the claims

  tions, characterized in that the block (27) determines

  undermining the extra rotation value of the part to

  machining for each helical groove to be formed is made

  born around a permanent memory (146).

  5. System according to any one of the claims

  previous arrangements, characterized in that the circuit (75)

  forming the stop signal of the workpiece to be machined

  carries a flip-flop (98) producing an end-of-use signal

  whose input is connected to the output of the counter (22) by the number of pulses corresponding to the length

  machining and at the output of the reset circuit

  tial (72), a flip-flop (99) producing a stop signal of

  rotation whose inputs are connected to the output of the

  number (29) of the number of pulses corresponding to the angle

  additional rotation, at the direct exit-from the

  cule (98) and at the output of the reset circuit (72), a flip-flop (100) producing a displacement origin position signal whose inputs are connected to the inverse output of the flip-flop (99), at

  outputting the counter (29) from the corresponding number of pulses

  at the additional angle of rotation, a former (103)

  impulse of origin of displacement of which one of the

  is connected to the inverse output of the flip-flop (98) and whose other input is connected to the output of the counter (22)

  the number of pulses corresponding to the length of

  swimming, a trainer (105) of position completion pulse

  angularly whose inputs are connected to the inverse output of the flip-flop (98) towards the output of the counter (29), an OR circuit (107), one of whose inputs is connected to the output of the former (103) and whose the other input is connected to the output of an inverter (104) and a shaper (106) of the original position signal whose inputs

  are connected to the output of the reset circuit.

  tial (72) and at the output of the OR circuit (107).