FR2525538A1 - CLUTCH / BRAKE CONTROL ASSEMBLY, ESPECIALLY FOR INDEXING TABLE - Google Patents

Abstract

CLUTCHBRAKE ASSEMBLY COMMAND WITH A COMMAND INTERFACE BETWEEN A COMPUTER AND A CLUTCHBRAKE ASSEMBLY TO LEARN WHAT POSITION EXISTS IN A PARTICULAR APPLICATION, WHAT MOVEMENT MUST BE CARRIED OUT TO ACHIEVE A STOP POSITION TO RESEARCH THE SYSTEM TO RESEARCH THE SYSTEM COMMANDS CARRIED OUT BY THE SYSTEM ITSELF UNTIL THE DESIRED STOP POSITION HAS BEEN REACHED WITH PRECISION, AND TO CONTINUE THE CORRECTIONS AS THE WORK CONTINUES TO COMPENSATE AUTOMATICALLY ANY ERRORS OCCURRING IN THE SYSTEM THEN 'THERE IS DRIFT AS A RESULT OF TEMPERATURE OR ANY OTHER FACTOR. AN APPLICATION WITH INDEXING TABLE 12 IS ALSO DESCRIBED, WHICH INCLUDES A CERTAIN NUMBER OF WORKSTATIONS, THIS NUMBER CAN BE EASILY MODIFIED BY SIMPLY REMOVING AND REPOSITIONING 140 TARGET BUTTONS WITHOUT CHANGING THE COMPUTER PROGRAM, AND INCLUDING A CLUTCH-BRAKE ASSEMBLY 42, 44 PNEUMATICALLY CONTROLLED, OIL COOLED, WHICH IS ENTIRELY MOUNTED INSIDE THE CONTROL SYSTEM OF THE INDEXING TABLE.

Description

1. The present invention relates to controlled clutch / brake assemblies

by computer, or together

  comprising a control interface between a microprocessor

  stopper or microcomputer and a clutch / brake assembly In a particular application, the present

  vention relates to an indexing table controlled by micro-

  computer that can be used with any number

  than positions in applications with indexing either

rotary is linear.

  Applications of the prior art with indexa-

  Controlled ge use complicated servo drives and DC drives

  to obtain a given objective point In the applications

  tions using index tables, we also used strictly mechanical control elements, such as a Geneva movement with search cam

  of position or the like Such applications have the

  suitable for being slow and bulky, requiring complicated control elements for acceleration and

  deceleration, and do not offer very high accuracy.

  Alternatively, coarse indexing can be performed with

a mechanical stop.

  The present invention uses a computer

  tor in combination with a clutch / brake assembly for 2.

  find out the position existing in an application

  particular, to know the movement that must be done

  to reach an "objective" point to proceed itself

  even to corrections until the desired "objective" point is reached with precision, and to maintain the correction action as long as the machining operations are in progress so as to automatically compensate for any

  error occurring in the system as a result of

  due to temperature or other factors The presence

  The invention can be used in a large number of devices.

  applications where a clutch / brake assembly is used, for example in oil well pumps where the operator will accelerate the pump to a certain point,

  note the value of the pressure, do a calculation to determine

  undermine the moment when the brake must be applied and used

  will be the instructive process to optimize the point and the duration of the brief stop of the pump and the acceleration and deceleration of the pump in order to obtain the

desired pumping rate.

  In an application relating to a table

  index, concept and control mechanism of the pre-

  sente invention are particularly simple and represented

  feel ahead in technology, reliability

  and flexibility compared to index tables of prior art

  rieur "Objective" buttons are arranged at selected points on the index table so as to indicate the indexing angle of the stop position of a part, o

  at least one operation is performed on the N'im-

  door what number of stations can be used This number can be easily changed by removing and reassembling the objective buttons in newly selected holes without

  make no changes to the mid order program

  croprocesseur Thus, the present invention relates to a reliable and flexible control and drive system, while being simple, for a rotary index table. The present invention also relates to an index table of the type

  previous, comprising a clutch / brake assembly

  Another pneumatic, oil-cooled die which forms a single unit mounted inside the table control system. Another object of the present invention is an extremely precise and programmable control system.

  for braking the part in the correct position.

  The index table and its control system, to the degree of

  high precision, can in turn order with precision

  robots and other auxiliary equipment associated with

  the machining operation to be performed on the part and at the

  environment in which this operation should be performed

killed.

  The present invention also relates, by making a slight modification, to the use of a microcomputer interfaced with a clutch / brake assembly, by bringing its reliability, its flexibility.

  and its simplicity in applications with linear index

re.

  The present invention in addition to the foregoing objects

  teeth, to isolate the harmful points of the network

  power supply during microprocessor operation

  or the microcomputer and the logic control

xiliary of the whole.

  The present invention will be well understood when

  of the following description made in conjunction with the

  attached sins in which: Figure 1 is a side sectional view of the index working table of the present invention; Figure 2 is an elevational plan view of part of either a clutch disc or a brake disc used in Figure 1; and

  FIG. 3 is a diagram of the control system

of the present invention.

  In connection with FIG. 1, an index machining table 10 has been shown comprising a round table 12 with a diameter of up to 2.50 meters which is fixed

  to a main drive shaft 14 arranged inside

  of a casing 16 and can be rotated indoors

  inside of this casing The casing 16 is cylindrical, having a side wall 17 in one piece with a base 18 and a 4.

  annular and removable upper part 19 fixed to the pa-

  lateral king 17 by a plurality of bolts 20 circumferentially spaced from each other The shaft 14 and the casing 16 are separated by seals 21, 22 and upper and lower roller bearings 23, 24 which

  are alternately lubricated at the bottom half of the ar

  bre by an oil tank 25 located inside the car-

  ter 16 The lower bearing 24 is supported by a

  removable lower tie 26 of the casing 16 and by a

  annular tie 28, extending radially inwards, of the casing 16 to which the part 26 is fixed by a

  plurality of bolts 29 A motor 30 is directly so-

  of a reduction gear mechanism 32, which

  is in turn integral with the entry of an information mechanism

  dexing 34 via a coupling 33 The reduction gear 32 presents

  te a high reduction ratio, around 24 to 1,

  and the motor 30 is designed to rotate continuously during

  during the operation of table 10 Another mechanism

  me with reduction gears 36, having a reduction ratio

  duction of about 8 to 1, is mounted in the housing 16.

  A main hub 40 is fret on the main shaft 14 at its middle part, Clutch 42 and brake 44 mechanisms are directly connected so as to act on the main hub 40 The input of the indexing mechanism 34

  is a shaft 46 mounted in bearings 48, 50 of the car-

  main gear 16, and carrying a bevel gear 52 at its end 54 The gear 52 is engaged with a gear

  conical annular 56 fixed to an annular driving element

  58 by a series of bolts 60 The mounting element

  tra Inement 58 is rotatably mounted on the main shaft

  pal 14 by tapered roller bearings 62 The

  drive ment 58 has an annular flange 64 to which is fixed a clutch disc 66, such as that

  shown in Figure 2, at points on the circle

  conference by 68 pin-type fasteners

  trestles 69 are used to reduce the bending of the disc 66 during the operation of the clutch 42, The clutch disc 66 sits in a recess 70 formed in a lower part 72 of the main hub 40 The lower part 72 of the main hub 40 is fixed to the hub body by a series of bolts 74 Similarly, a

  annular brake disc 76, similar to that shown

  felt in FIG. 2, is fixed to the upper part 19 of the main casing 16 by a series of fasteners 78 of the type

  pin circumferentially spaced from each other

  very and by spacers 79 so as to reduce the bending of the disc 76 during the operation of the brake

  44 The brake disc 76 is placed so that

  milaire, between an upper part 80 of the main hub

  fixed to this hub by circumferentially spaced screws 82

each other.

  The main hub 40 further comprises a flange

  that annular 84, disposed radially outward, to guide an annular piston 86 disposed above The piston 86 has an upper part 88 and a lower part 90 fixed together by screws 92 and is provided with grooves 94 arranged radially inward which move on grooves 96 directed radially outward from the main hub 40 Seals 100 and 102 are also mounted between the outwardly disposed flange 84 of the main hub 40 and a

  flange disposed inward 104 of the lower part

  lower 90 of piston 86 so as to create a chamber

  106 for actuating the piston A series of evi-

  dement 107, 108 circumferentially spaced from each other are arranged in the piston 86 and the annular flange 84 of the main hub 40, respectively, in which are placed compression springs 110 so as to load the piston so that it engages the brake

  when no movement of the table 10 is desired.

  A channel 112 is formed in the main hub 40 and communicates with a channel 114 extending radially in the main shaft 14, which in turn communicates with a channel 116 extending axially in the main shaft 14 up to a inlet 118 located at the end

  from the main shaft 14 and outside the casing 16.

  6. The inlet 118 in turn communicates with a

  pressurized air source (not shown) Thus, the em-

  clutch 42 and brake 44 are mechanically locked via the pneumatically controlled piston by the compression of the brake springs 110 and an action air pressure.

  clutch 42 0.45 M Pa to obtain full

  no capacity of the embodiment described.

  Friction discs 66, 76 of the clutch

  42 and brake 44 are produced as shown in fig-

  re 2, with blades 120 between the main body 122 and

  flanges 124 which can come into contact with the pins

  68 or 78 so as to take account of the bending of the discs 66, 76 One side of the friction disc 66 or 76 is in contact with the plates 72 or 80 which are doweled

  in the hub 40 The other side is in contact with the piston

  tone which is grooved in the hub 40 This results in the creation of an anti-backlash torque which is equal to the

half of the total torque.

  Main housing 16 is filled with light oil.

  re up to a level above the clutch 42.

  Oil is supplied to the upper bearing and brake by a 0.25 horsepower pump / motor combination which is mounted on the side of the main housing to introduce oil

in an orifice 130 of the casing 16.

  An ootic encoder 132 at 5000 pulses per revolution is driven by the table 12 via a gear ratio reducer 134 20/1 fitted with an anti-backlash system. This has the effect of applying to the controller one pulse per 0.08 mm angular displacement for a workpiece diameter of 2.5 meters, at

  000 pulses per turn of the table.

  "Objective" buttons 140 are mounted on the

  table 12 by press fitting in holes

  sés 142 Table 12 can be pre-bored so as not to

  wears what combination of a number of positions, with the 140 buttons inserted into the correct holes for

  indexing required Buttons 140 must have-em-

  specific investments, but have no specific reference 7.

  at the work station which must also be placed with pre-

  cision compared to others So, one can choose

  any number of stations without altering the pro-

  gram of computer 154 of the control circuit Workstations are mounted approximately half way between the buttons 140, Figure 1 shows the buttons that operate proximity switches 144, However, the proximity switches may not have the required reproducibility precision In any case, an optical test pattern can be used to have an even greater precision. The precision of the index is obtained thanks to a

  computer instruction process at the time of installation

  or when the equipment has not operated for

  a certain period of time It is estimated that this cycle of

  truction will not exceed 8 to 10 index.

  To illustrate the operation of the system, we will assume that we have a table with five workstations. The number of counts between workstations will then be 20,000 (5,000 pulses multiplied by 20 (ratio

  reduction) divided by 5 items).

  On initial startup, the first procedure

  consists in determining the exact relative angular position

  te between the buttons 140 and the desired breakpoint of the pieces The table 10 is moved so that one of the

  buttons 140 pass to the right of a proximity sensor 144.

  This has the effect of resetting the counting circuit to zero. The counting circuit resets to zero each time a button 140 passes to the right of the sensor. The table 10 is then continued to move until the

  parts are exactly in their correct rear position

  rêt, that is to say in the desired position The best-

  re procedure consists in advancing the table little by little

  tit until it is just below the desired final stop position, stopping the main motor and manually turning the coupling 33 located between the reduction gear 32 and the casing 16 of the indexing device, the clutch 42 being engaged, this stop position is 8,

  blocked in a memory circuit 152 (FIG. 3) in ac-

  operating a key switch 150 as a posi-

  Stop count sought, The actual count is displayed on a display device. For example, suppose the counter indicates 9,300; the value (> 5000) of this number

  means that the buttons 140 are not located halfway

tance of workstations.

  Simple calculations based on the load of the devices

  clamping positives and coins indicate an angle of

  lo stop 15 degrees in the embodiment shown.

  degrees represent 100,000 times 15 divided by 360 =

  4166 counts The number 5134 (9300-4166) is then

  very as brake application position in the circuit

  158 of the brake application memory (Figure 3).

  An index is then initialized Suppose that the actual stop position is 8500 On the following coordinate system,

  the computer will automatically delay the position

  brake application (and brake application memory) of 800 counts Thus, the brake will be applied to 5934

  counts instead of 5,134 On the following benchmark, suppo-

  sounds that the counting of the actual final stop position is 9320 The stop order for the third index will be

  then 5934 20 = 5914 This procedure continues until

  until the actual final stop count is 9300 (po-

  stop position sought) plus or minus 2 for two consecutive indexes A signal will then be sent to start the robots, etc., so that they work on the pieces placed on the table 10 A counting error of plus or minus 2 gives a positioning accuracy of plus or minus 0.15 mm for a table 10 of 2.40 meters in diameter. The manufacturing taking place, suppose that after

  the 15th index the count goes to 9303 On the following index

  Before, the order of application of the brake would be given to 5914 -

  3 = 5911 The computer continues to monitor the po-

  actual stop position and continues to modify the position of the brake application order as necessary With this procedure, the effects of temperature and other

9 2525538

  factors that can cause the machine to drift

  are automatically canceled by the computer.

  Considering another possibility, suppose that after having treated a few dozen or hundreds of parts, the operator decides that a better position

  9296 instead of 9300 The operator enters sim-

  Also this new number as the desired final stop position (via the key lock switch), passes a few indexes by way of instruction and

resumes manufacturing.

  It is currently envisaged that each time the equipment is stopped for more than 30 minutes

  approximately, an instructional cycle is required A transducer

  temperature sensor can also be incorporated into the control system The temperature control as

  brake application order modifier can eliminate

  instruction cycles, except for periods

prolonged stops.

  The microcomputer and the auxiliary logic are powered by a cadmium-nickel battery with a

  charger incorporated so as to isolate harmful spikes

in the power network.

  A schematic representation of the control circuit is given in FIG. 3 The counter 132 is reset to zero each time a button 140 passes to the right

  a detector 144, but also has pulses

  When the workpiece has been placed in the desired stop position, the locking switch 150 is actuated so as to

  block the selected count at this position in the circle

  cooked from memory 152 of the microprocessor or micro-computer

  tor 154 A comparator 156 located inside the mid

  crocomputer 154 compares the current count given by the counter 132 with the counting blocked in the circuit of

  3-5 memory 152 so as to determine the accuracy of the position

  After performing the calculations described above

  above, the brake application count is also placed in circuit 158 of the application memory of the computer brake 10. This count is also transmitted to a comparator 160 (which may or may not be the same as the

  comparator 156) When the counter 132 reaches the

  stored in circuit 158, brake 44 is applied.

  Workpiece and table 12 will stop, at which point this count is compared to the desired stop position in memory blocking circuit 152 If the result of the comparison is within the range (more or less 003) chosen ( YES), a signal is transmitted to the robot or other machine so that it begins its operation At the end

  of operation, the robot or the machine signals to the em-

  clutch 162 that indexing is required on the next station.

  If the comparison result is not within the range

  (NO), the clutch actuator performs a new in-

  dexing and the computer changes the application count

  brake in memory circuit 158 as described above

  cedently (adding or subtracting the difference between

their real and desired value).

  The appreciation of some of the measurement values indicated above must take into account the fact that they come from the conversion of Anglo-Saxon units into

metric units.

  The present invention is not limited to the examples

  ples of realization which have just been described, it is on the contrary susceptible of modifications and variants

  which will appear to those skilled in the art.

he.

Claims (9)

  1 clutch / brake controlled assembly, used in a machining operation, characterized in that it comprises: a drive means, a driven element; clutch means for operatively associating the drive means with the driven element when the clutch means is engaged; brake means; and means for controlling the clutch means and the brake means   in order to control the position of the driven element,   bearing a means for indicating a zero point, a means   to apply the brake so that it stops the driven element   born, a means to learn in which position the driven element is stopped relative to the zero point, a means   to learn which movement the driven element should make   re to reach a desired stop point (objective),   established with respect to the zero point, a means for self-cor-   correct any error between an actual stop position of the driven element and the stop-wanted point until   that the desired breakpoint has been reached internally   within a selected range of precision, and a means   to continue correcting any error that occurs   between an actual stop position of the driven element   born and the desired stop position, while the operation   machining continues so as to automatically compensate-   lie any error occurring in the system while   the actual stop position shifts relative to the po-   stop position sought due to temperature or any other factor.   2 Clutch / brake assembly as claimed   tion 1, characterized in that the control means   also takes a means to change the point at will stop wanted.   3 Clutch / brake assembly as claimed   3 b cation 1, characterized in that it further comprises a battery means for supplying it and a charger means intended for the battery means,   4 Clutch / brake assembly controlled, characteristic   12. laughed at in that it includes; a drive means; trained means; a   clutch means functionally associated by means of   and the driven element so that, when the clutch means is engaged, the driving means drives the driven element; an associated brake core   functionally to the driven element; and a means of   command comprising means for detecting the position of   the element driven by any position of this element,   taking an output means, means for choosing a desired stopping position of the driven element; a way   to apply the brake means so that it stops the element   driven to the desired stop position; comprising means for choosing a position at which the brake means is actuated by the actuating means, a   means to compare the output means of the detection means   tion at the desired stop position selected; and a way to   correct the position selection means of the means of ac-   operation of the brake means if the driven element is not stopped within a chosen range of precision at the chosen stop position, comprising means for   actuate the clutch means so that the slack begins of the driven element.   Clutch / brake assembly according to claim 4, characterized in that it further comprises means for associating a part with the driven element, and means for controlling the operation of a device capable   to perform the desired work on the part.   6 Indexing table for at least one part, characterized in that it comprises: table means for supporting a part; drive means including motor means; a casing arranged in a contiguous place by means of table; a clutch means inside the casing   to cause the table means to move in combination   ciant the drive means by means of table; 13. a brake means inside the casing to stop the movement of the table means; means for operatively associating the clutch means and the brake means with the table means; and a control means, comprising   a means arranged on the table for if-   generalize the position of the workpiece on the table means with respect to a preselected desired stop position; computer means for determining the position of the workpiece on the table; and   a means for actuating the em-   clutch or the brake means in response to the position of   the part determined by computer means.   7 indexing table according to claim 6, characterized in that it further comprises means for associating a part with the driven element, and means for   control the operation of a device capable of   cut a desired job on the piece.   8 indexing table according to claim 6, characterized in that the table control means further comprises means for correcting the actuation position of the brake means in response to any error   occurring between the actual stop position of the workpiece   this on the table means and the desired stop position room preselection.   9 Indexing table according to claim 6,   characterized in that the table means comprises a cer-   any number of workstations and a means to modify   pride the number of positions without changing the computer means   nateur, Device with indexing table, on which at least one part is arranged, characterized in that it comprises: a table means for supporting the part   in a chosen position, comprising a trans-   mission to order his movement; a casing supporting the table means; 14, a drive means disposed at least partly in the casing, comprising a motor means;   a functional integral clutch means-   ment of the drive means; a brake means functionally integral with the casing;   a means for alternately engaging the mo-   clutch yen and the brake means in the transmission element, comprising a biasing means for causing the brake means to engage in the transmission element;   a means for indexing the table means   in order to place the piece consecutively at the chosen work stations, comprising: a target means (objective) arranged on the table means for signaling positions on this means, a means for detecting the target means,   an associated computer means functions   the detection means to determine the po-   exact relative position between the target means and the part   this disposed on the table means, comprising an output means for signaling; and means for controlling the engaging means so that the brake means is engaged in response to the signal from the output means of the computer means.