FR2468527A1 - POWER CONTROL DEVICE FOR TRANSMITTING ENERGY FROM AN ALTERNATING CURRENT SOURCE TO A VIBRANT DISPENSER, AND ASSEMBLY COMPRISING SUCH DEVICE AND DISPENSER - Google Patents

Abstract

The invention relates to a power control device for a vibrating distributor. This device 18 comprises a thyristor 32 which is triggered by the voltage appearing at the terminals of a capacitor 33 which is charged by a circuit connecting it to an alternating current source. A remotely controlled switch 26 is placed in the charging circuit of capacitor 33 so that this switch 26, by opening and closing, selectively controls the application of power to the vibrating distributor 11, the switching being effected in the load circuit which is traversed by a weak current Field of application: vibrating distributors of screws, nuts and other small parts.

Description

1. The invention relates generally to control devices

  vibratory distributors, and more particularly such control devices having

  a possibility of breaking on weak currents.

  Vibratory distributors for small parts such as screws, nuts, plastics and other parts are generally supplied with alternating current and tuned electromechanically at a frequency of 60 or 120 Hz. In the case of bowl, a bowl intended to contain the pieces has a

  inner track that rises helically along its circumference

  and which is mounted on an intermediate part

  on a base. The intermediate part is connected to a source of alternating current by means of a device of

  power regulation and it's tuned electromagnetically

  only to vibrate the bowl. The vibration of the bowl

  causes an ascent of the pieces along the heli-

  coldale. The tuned intermediate portion of the vibratory feeder has a relatively large damped inductive load for the power source. Various control devices have been used to vary the power. supplied by an AC power source to a vibratory feeder. These devices

  power control operate in the mono-

  alternation or following the two half-wave

  Vibratory distributor is tuned to 60 Hz or 120 Hz, respec-

  tively. During operation, the control device

  power transmission transmits a portion of each period of the power source (or each half-period in the

  120 Hz operation) to the vibratory feeder.

  One way of adjusting the power supplied to the distributor is to divide the voltage of the source

  power supply by means of a resistance divider circuit.

  Another common method is to apply the voltage of the AC power source to the distributor

  part of each period or half a

  period of the AC wave. Trigger-controlled semiconductor 2. thyristor circuits can be used in such control devices o, in the case of a two-wave system, the thyristor is tripped at one point in each half-period of the sinusoidal voltage of the AC power source to connect the distributor to the power source during the game

remaining half-period.

  In all these sets with a regulating device

  vibratory dispenser and dispenser, it is necessary to cut

  the distributor's power supply during periods of

  Moments during operation, for example when parts are jammed along the track leading from the distributor to the workstation parts. So far, sensors have been placed along the distributor tracks to determine if there is blockage of parts along the track, and high current switches have been placed in the feed line and have been ordered in order to cut off the current transmitted to

  distributor vibrating through the control circuit

  lation. These switches are placed directly on the connection leaving the AC supply line and traversed by the total charging current of the distributor whose order of magnitude is several amperes. Control currents of this magnitude require relays and other large sized components, and

  contacts of these switches for high currents

  often under the effect of wear, which requires the

replacement of the switch.

  The invention therefore relates to a control device

  for a vibratory distributor assembly, having

  cutoff possibilities on low intensity currents.

  The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting example and in which:

  FIG. 1 is a diagrammatic perspective view

  a vibratory feeder assembly and a power control device according to the invention; 3.

  FIG. 2 is a diagram of the circuit of the arrangement

  control device of Figure 1; and - Figures 3A to 3E are curves showing

  the voltage waves at various points in the circuit of FIG.

  2. FIG. 1 shows a vibratory distributor 11 which comprises a bowl 12 intended to contain parts, an intermediate part 15 intended to vibrate the bowl and a

  13. The vibrations of the bowl 12 have the effect of displacing

  parts 14 along an integral circumferential track.

  16 and take them out of the bowl 12 on a straight track 17 feeding. The pieces travel on track 17 to a next post, for example to be subject to

  operation performed in a machine (not shown).

  FIG. 1 also shows a power regulation device 18 connected by a connection 19 to a conventional AC power supply at Hz. The energy of the AC source is transmitted via the regulation device 18 and by a connection 21 to the vibratory distributor 11 to make it vibrate. The regulation device 18 comprises a main switch 22 and a power adjustment button 23 making it possible to determine the quantity of energy

transmitted to the distributor 11.

  A switch 26 is connected by lines 24 to the regulating device 18 and can be operated to cut off the power supply to the distributor 11 via the connection 21, as described in more detail below. This switch 26 is controlled by a sensor 27 which detects the appearance of slowing down of the parts 14 at the location of a transducer as indicated in FIG.

  28. This slowing down of parts may be due to difficulties

  encountered in the machine placed downstream and used

  the parts, or it can result from a blocking of the downstream parts, on the track 17. When a slowdown of the parts is detected by the sensor 27, the switch 26 is actuated so as to provide the distributor 11 a low

  breaking current, as described in more detail below.

  4. FIG. 2 represents a preferred embodiment of the circuit of the regulating device 18 of FIG.

  power of Figure 1 and its connections to the distribution

  vibrating scorer 11, switch 26 and lines 19 connected to an AC power source. The distributor 11 has a substantially inductive and significant load impedance and is connected in parallel with a

  resistor 31 which constitutes a minimal resistive load.

  This combined load is connected in series with a controlled bidirectional rectifier 32, of the "Triac" type, and the series circuit formed by the "Triac" and the load is connected to the lines 19 from the AC power source. The main switch 22 is connected in series with one of the lines 19 of the AC power source to control the application of the alternating current to the circuit

regulation. -

  When the "Triac" 32 is not conductive, a minimum current is supplied to the distributor 11 and the latter is thus substantially stopped. When the "Triac" 32 is conducting, the distributor is connected to the terminals of the

  source of alternating current and is subject to an excitatory

  maximum during the conduction period of the "Triac". The "Triac" 32 is triggered, during normal operation, to be driving for part of each period or for half a period of the voltage of the AC power source, the conduction time of the " Triac "determining the amount of energy supplied to the

distributor 11.

  For the "Triac" 32 to be triggered following a

  timing to provide the distributor with the power

  this desired, a capacitor 33 is charged through the

  two capacitor circuits, and the voltage of this capacitor is used to apply pulses to the trigger of the "Triac" 32. When the voltage of the capacitor 33 reaches the breaking voltage of a bidirectional diode or "Diac" 34, a trigger pulse is applied to the trigger of the "Triac" 32 and the latter becomes conductive. In the case of a two-wave operation, 120 Hz, a jumper 36 is connected in parallel with a diode 37 so that the two polarities of the capacitor voltage 33

  applied to the "Diac" 34. This gives two impulses

  triggers, namely a positive impulse and a negative impulse, for the "Triac" 32 at each

  full period of the voltage wave of the power source

  tation. The voltage applied to the trigger of the "Triac" 32 is indicated in Ve in FIG. 3E. If the jumper 36 is not connected in parallel with the diode 37, only the positive voltage (with respect to a common node 40) of the capacitor 33 is transmitted by the diode 37 to the "Diac" 34. In this case, only the positive impulse triggering the form

  Ve wave of Figure 3E is produced.

  To obtain positive and negative

  capacitor 33, this. The latter is connected by two load circuits to the AC power source. A first charging circuit starts from a node 50 and passes through a jumper 38 or the switch 26, a potentiometer 39 and a resistor 41. The node 50 is separated from one of the lines 19

  arrival of the AC power source by resisting

  a relatively low minimum load factor 31, and the damped inductive load of the distributor, placed in parallel with the resistor 31. The node 50 is also connected to one of the main terminals of the "Triac" 32 and is therefore connected to the node common 40 when the "Triac" leads. When

  the "Triac" 32 is not conductive, the node 50 is sensitive-

  the voltage of the line of the alternating current

  native and the capacitor 33 is charging through the potentio-

meter 39 and resistance 41.

  The time range for turning on the

  "Triac" 32 during a period of the voltage wave is extended

  by the presence of a second charging circuit which starts from the node 45 connected by the general switch 22 to one of the

  lines 19 of the AC power source.

  The voltage at node 45 is practically unaffected by

  by the state of the "Triac" 32 and it charges a capacitor 42 under the voltage of the AC power source and through a resistor 43. The voltage of the capacitor 42 causes the capacitor 33 to be charged to

through a potentiometer 44.

  The operation of the circuit, starting from a half-positive period (taking the voltage of the node 45 relative to that of the node 40), will now be described. The line voltage is initially applied to the distributor

  11 while the "Triac" 32 drives, the voltage Va of the distribution

  goal scorer being shown in Figure 3A. The voltage across the "Triac" 32 is indicated in Vb in FIG. 3B, and the sum of the voltages Va and Vb is obviously equal to the voltage of the supply source between the node 45 and the node 40. From the beginning of the positive half-cycle up to the time t3, the input voltage is applied to the distributor 11. The "Triac" 32 remains conductive during this initial portion of the positive half-cycle of the input voltage due to the passage of the reverse current persistent in the "Triac" and in the distributor, because of the strong inductance of this

  latest. When the "Triac" 32 is blocked at time t3, the disc

  tributor 11 is no longer excited and the source voltage appears across the "Triac" 32. In a two-wave operation, the time t4 of the negative half cycle

  corresponds to the time t3 of the positive alternation.

  At the beginning of the positive half-wave of the voltage wave of the source, the voltage Vc of the capacitor 42 becomes positive, so that this capacitor charges from the node 45 and through the resistor 43 and that it serves to to charge, via the potentiometer 44, the capacitor 33 determining the tripping time of the

  "Triac". Once the "Triac" 32 is blocked, the condensation

  The driver 33 is also charged via the circuit starting from the node 50 and passing through the potentiometer 39 and the resistor 41. When the voltage across the capacitor 33 reaches the breaking voltage of the "Diac" 34, the "Triac" 32 is triggered and he becomes driver again at time t1

shown in Figure 3A.

  At this time, the voltage Vb of the "Triac" returns to zero and the voltage of the source is again applied to the distributor 11. In addition, at the time t1, there is a slight drop in the voltage V of the capacitor 42. and an

  greater drop of the voltage Vd of the capacitor 33.

  As indicated above, the tripping pulse Ve determines the time t1. The charging time of the capacitor 33, that is to say the time taken to reach the breakdown voltage of the "Diac" 34 and to produce a pulse of

  triggered, is determined by the settings of the potentio-

  Meters 39 and 44. The lower the resistance of each potentiometer, the faster the capacitor 33 charges during each alternation and the faster the "Triac" is made conductive. It should be noted that the application of a lower power to the distributor not only has the effect of moving to the right the moment t1 triac triggering 32, that is to say towards the axis of ordered on the

  Figure 3A, but also move to the left, that is,

  that is to say towards the beginning of the positive alternation of the voltage wave of the power source, the time t3 of breaking or extinguishing the "Triac". This approximation of the cut-off time of the "Triac" is due to the fact that the residual current passing through the distributor decreases when the time of

  trigger, at the end of the previous alternation, decreases.

  Consequently, the regulation circuit 18 makes it possible to regulate substantially continuously and completely the power supplied to the distributor. The power supplied to the distributor is all the greater as the "Triac" is triggered and made conductive earlier. The potentiometer 44 is preferably

  set at an initial value during a settlement operation.

  calibration, and the potentiometer 39 is adjusted by means of a

  button 23 which makes it possible to adjust the power level

  When calibrating the regulating device 18, the potentiometer 39 is placed in its maximum resistance position in order to provide the capacitor 33 with the lowest charge current by this charging circuit. The potentiometer 44 is then adjusted until the time t1 substantially corresponds to t0, that is to say the point at which the voltage wave of the source passes through the ordinate axis, so that a power The minimum voltage is supplied to the distributor 8. In a two-wave operation and once the potentiometer 44 has been set, the time t2 is at the point of

  next crossing of the voltage of the source. The potential

  Meter 44 being thus set, any adjustment of the potentiometer 39 subsequently made to reduce the resistance causes an increase in the charging current of the capacitor 33 so that the "Triac" 32 lights up earlier. It is possible to provide the dispenser 11 the desired amount of energy by adjusting the potentiometer 39 to turn on the "Triac" 32 at each period or each half-period at the appropriate time. According to the invention, the switch 26 is connected in series with the load circuit of the capacitor 33 passing through the potentiometer 39 and the resistor 41. The switch 26 is mounted in this charging circuit, the jumper 38 is removed. As shown in FIG. 1, the switch 26 is connected externally to the regulation device 18 and is controlled by a sensor, for example the sensor

  detect a slowing down of the pieces on track 17 of

  mentation. When the switch 26 is open, it opens the charging circuit through the potentiometer 39 and the resistor 41, and the regulating device 18 transmits a minimum power to the distributor. It appears that by placing the switch in this charging circuit, it becomes unnecessary to make switches under high current, in series with the distributor 11. In fact, the current passing through the charging circuit by the switch 26 is less than the total charge current of the trigger control capacitor 33 of the "Triac", since there is a second circuit of

  load passing through resistor 43 and potentiometer 44.

  In general, the charge circuit current is of the order of a few milliamperes and the distributor current is

the order of a few amperes.

  The regulation circuit 18 also comprises two automatically varying resistors or varistors 46 and 47 which limit the amplitude of the transient voltages between the lines 19 of arrival of the voltage source and the terminals of the "Triac" 32. The regulation device also includes 9. a damping circuit connected to the terminals of the "Triac" 32 and

  comprising a resistor 48 connected in series with a capacitor

  49 to limit the rate of voltage rise

at the terminals of the "Triac".

  Although the control circuit has been described in its application to a bowl-type vibratory feeder, it is obvious that other types of vibrating coin dispensing devices can also use the circuit.

  18 of regulation. Such devices include, for example,

  ple, chain parts distributors and hoppers

Vibrating storage.

  It follows from the previous description that the

  power regulating device according to the invention,

  connected to a device of the vibratory distributor type, allows switching under low current of the power supplied to

  the device in response to conditions detected externally

  laughing. This external switching of the regulating device

  power can be achieved depending on the conditions

  flow of coins, as shown in the form of

  shown, or according to other conditions

  requiring the shutdown of the vibrator.

  It goes without saying that many modifications can be made to the regulation device described and

  shown without departing from the scope of the invention.

10.

Claims (8)

  1. - Power control device for transmitting power from a power source   alternating current to a vibratory distributor (11),   characterized in that it comprises a thyristor (32) comprising main terminals and a trigger, said thyristor being triggerable by means of its trigger, which can assume a conducting state and a nonconductive state and can operate in such a way that, when is in a first state, energy is supplied by the AC power source to the vibratory feeder and, when in its other state, energy is not transmitted from the AC source to the vibratory feeder, at least one of the main terminals being connected to the vibrating distributor, and at least one of the main terminals being connected to the source of   alternating current, a capacitor (33) for   thyristor, being mounted between the gate and one of the main terminals of this thyristor, a charging circuit being between the AC power source and the capacitor, and a switch (26) being associated with this charging circuit and can be operated so to modify the impedance.   2. - Regulation device according to the   cation 1, characterized in that it comprises a second condensation   (42) connected by a load circuit to the AC power source and another load circuit at first capacitor (33).   3. - Control device according to the   cation 2, characterized in that it comprises a sensor (27) remote from the control device (18) and controlling the switch (26) associated with the charging circuit included   between the AC power source and the first capacitor sator (33).   4. - Device. regulation according to the   cation 3, characterized in that one of the main terminals of the thyristor (32) is connected to the vibrating distributor (11) and in that the other main terminal is connected to the source   AC power supply. 11.   5. - Regulation device according to the   cation 4, characterized in that the charging circuit of the first capacitor (33) comprises a first adjustable potentiometer (39) and in that the charging circuit between the first capacitor and the second capacitor (42)   comprises a second adjustable potentiometer (44).   6. Vibratory distributor assembly and   control device, characterized in that it comprises a vibratory distributor (11) of parts (14) having a track   (16, 17), a device (18) for regulating   which comprises a thyristor (34) having main terminals connected to the vibratory feeder and an ac power source, and a trigger, a capacitor (33) connected to the gate of the thyristor and a charging circuit, included between the AC power source and the capacitor, comprising a switch (26) controlled remotely.   7. An assembly according to claim 6, characterized   in that it also comprises a sensor (27) arranged to detect accumulations of parts (14) on the   track and can be operated to control the said switch (26).   8. An assembly according to claim 6, characterized   characterized in that the regulating device (18) comprises a second capacitor charging circuit (33) which comprises a resistor (43) and a second capacitor (42) connected to the terminals (19) of the AC power source, and a potentiometer (44) mounted between the second capacitor and the first capacitor.