Патент USA US2405066код для вставки
July 30, 1946. ‘ J, D_ Em 2,405,066 - POSITION REPRODUCING MECHANISM Filed March 28, 1942 2 Sheets—$heet l INVENTOR JAMES D.TEAR BY If)?‘ ATTORNEY 3%, 194-5, .3, 5;), TEAR POSITION REPRODUCING MECHANISM Filed March 28, 1942 2 Sheets-Sheet 2 mm llllllllll?llllllll'l I I] INVENTOR JA M Es D. TEAR Z0214 ,a/QM/I- ' 1-!TTORNE Y Patented July 30, 1946 2,405,066 UNITED STATES PATENT OFFICE 2,405,066 POSITION REPRODUCING l‘JIECHANISM James D. Tear, Great Neck, N. Y., assignor to Ford Instrument Company, 1110., Long Island City, N. Y., a corporation of New York Application March 28, 1942, Serial No. 436,685 9 Claims. 1 (Cl. 172-239) 2 The invention relates to mechanisms for repro ducing position and particularly to such mech tio of movement thereto that the coarse receiver bears to the ?ne receiver. The two contacts are anisms of the follow-up type in which the trans spaced a predetermined distance when the relief connection is in its biased position, and the dis mission system operates a control member for a power unit termed a servo-motor. The invention is applicable with self syn chronous transmissions in which the torque of the receivers is zero when they are in synchro nism with their transmitters, and which employ dual transmissions of different speed ratios, the units of positional value transmitted by the low speed transmitters being relatively large or coarse, and those transmitted by the high speed transmitters being relatively small or ?ne. A characteristic of embodiments of the inven tion is the fact that there is but a single control member for the amplifying power unit, and that this control member is operated by a drive which is selectively controlled by the ?ne and coarse re ceivers depending upon the positional error, that is, the extent to which the driving or motion re ceiving member fails to synchronize or agree in tance is decreased in proportion as the relief con nection departs from its biased position until the contacts engage whereupon the auxiliary motor is energized and assumes control of the control member. This occurs before the condition is reached where the relief connection would jump to a false position and thus throw the control member further out of phase relation with the ?ne receiver rotor. The invention also contemplates suitable clutching means in the connection with the aux iliary motor which is engaged only When the coarse receiver is in charge and thus relieves the ?ne receiver of the load of the armature so long as the ?ne receiver is in charge. This invention is adapted for actuating a ser vo-motor control of the type in which the veloc ity at which the power driven response ap proaches the velocity of the transmitted move position with the original or motion transmitting member; and it is with the proper transfer and ment, such as a signal, is limited to some func maintenance of this selective control that the in 25 tion of the discrepancy between the received sig vention is more especially concerned. nal and the power driven response. Such a type In such follow-up systems the power unit op of control is desirable when synchronizing the erates reversely upon the control member to shut. response with the signal as in starting up the sys oiT the power when the transmitted movement is tem or whenever the response may depart from completely reproduced. The movement of the ' the signal for any reason, such as a shift of the control member is usually limited in both direc receivers to a di?erent pair of transmitters. tions and a relief connection or yieldable coupling Other objects and advantages of the invention in the drive from a receiver to the control mem will appear from the following description of the ber frees the receiver rotor from limitation in embodiment of the invention shown in the ac synchronizing with its transmitter. The con companying drawings. struction of this relief connection is such that Fig. 1 shows diagrammatically an embodiment the drive for the control member is biased to a of the invention used in connection with a sim positional relation with the receiver rotor and is ple form of servo-motor control. self synchronous or self-correcting within the Fig. 2 shows a modi?ed form of servo-motor range of a limited error beyond which it tends to 40 control in which the servo-motor is controlled so increase the error in order to return to biased re that the velocity at which the error in response lation, by returning in the wrong direction. is removed is a function of the error. In accordance with this invention an auxiliary power unit arranged under the control of the coarse receiver is connected to supplement the drive to the control member and to cause the coarse receiver to assume charge of the control member for the servo-motor as long as the error The two speed transmission shown is of the type disclosed for example in the patent to Hew lett and Willard No. 1,559,524. The two trans mitters l and 2 are geared together by gearing 3 such that motion applied by a motion transmit ting member 4 will move the rotor of transmitter exceeds the limited amount. The auxiliary pow l at a high speed relative to that of the rotor of er unit may be an electric motor the energizing 60 transmitter 2, say 36:1. The rotors of the re circuit of which includes a pair of contacts one ceivers 5 and 6 will have the same ratio of move of which is moved with the coarse receiver and ment. the other of which is moved in the same path by The rotor of the ?ne receiver 5 is connected the drive for the servo-motor control member by a shaft 1 to one side of a centralized relief operated by the ?ne receiver, and at the same re. 55 connection or yieldable drive coupling 8 the other 2,405,066 3 4 34 is engaged, and that the torque of motor 36 side of which is connected by shaft 9, bevel gears in and shaft ii to one side of a control differ is applied on shaft 9. ential l2. Speci?cally the coupling 3 is of the construction shown in the patent to Poitras and Tear N0. 2,13%,488. going description. The yieldable drive couplings The operation will be apparent from the fore have on one side a cam and on the other a spring pressed follower, the cam surface tapering in both A reversible power motor l3, shown as an elec directions from a high spot to a diametrically op~ posite low spot The spring causes the follower to tric motor, is connected by shaft it, bevel gears 55 and shaft it to a second side of control differ ential l2, the shaft l4 also being connected to drive the load which it is desired to position in ac seek the low spot. If the two sides get out of an 10 gular agreement so far that the cam rides over cordance with the transmitted positional value. the high spot the spring will return the follower to the low spot by a continuation of movement in the same direction and thus further increase the error. In other words the drive is self correcting able electric contact, which is energized by'a source of power it and is alternatively connected to ‘the 15 only up to substantially 180° of error. It is this fact that determines the spacing of motor l3 by the leads of reversing contacts iii the contacts 26 and 27. The arms 25 and 23 are and 2s. The motor is is connected to the other so set that the contact 24 is midway between con side of the power source it by a lead 2|. tacts 26 and 27 when the couplings are in their It will be understood that as the rotor of the receiver motor 5 is turned in response to the 20 biased position. Let it be assumed that power mo tor i3 lags in its following and hence that the in transmitted value, the contact ll will be moved put of shaft I i into the differential I2 is not-coun to close one or the other of the motor circuits and teracted su?iciently fast by the input of shaft [6. the power motor will rotate in a direction to posi The contact ill will be rotated against either con tion the load in accordance with the movement of the motion transmitting member, and at the 25 tact id or 2b and as the error accumulates the cam follower of coupling 8 will ride up the cam same time the movement of shaft it will be trans surface against the spring tension. Arm 28 sim mitted to the differential it through the shaft ilarly lags but in the reduced ratio, and the spac i6 and neutralize the input to the differential, ing of contacts 26 and 21 is so determined that thereby opening the contact ll and stopping the 30 the appropriate one is engaged by the contact 24 motor 63. just before the cam follower reaches thehig'h spot The shaft 22 of coarse receiver 6 is connected of the cam and hence before the coupling 8 can through a yieldable coupling 23, similar to cou jump ahead. The motor 36 is thereby energized, pling 8, to rotate an insulated contact 2" on the and the clutch being at the same time closed, the end of radial arm 25. The contact 263 cooperates with two insulated contacts 26 and El located on 35 motor torque is applied to the shaft 9 in a direc tion to prevent the shaft from jumping ahead opposite sides of the contact 24 and carried by if the error increases and the follower passes over the arm 23 which is mounted for rotation co the high spot, and thus from increasing the effect axially with the arm ‘.25. The arm 28 is directly of the error. connected to and is rotated by a gear 29 which is Assuming the ratio of 36:1, one complete rota driven through reduction gearing 3%] by a gear 3! 4.0 tion of the ?ne receiver or 360° of movement of on shaft 9. The ratio of the gearing '33 is the the member ll represents one-thirty-sixth of a same as that of the gearing?, and hence the ro complete rotation of the coarse receiver, or 10° tation of the arm 28 relative to the shaft 9 is the of movement of the arm 25. If the follow-up is same as the ratio of rotation of the coarse trans accurate the contacts 2% and 2'! will move along in mitter unit relative to that of the ?ne transmit synchronism with the contact 24 and keep it cen ter unit. tralized. However as the follow-up gets'out of The shaft 9 carries a gear 32 which is geared synchronism the coupling 58 begins to yield and with one member 33 of a clutch unit 34. The the drive of arm 28 gets correspondingly out of other member 35 of the clutch unit is rotatably connected to the armature of a reversible electric 60 step but at the reduced ratio. When the shaft fl is 180° out of phase with the shaft 1, the arm 28 motor 36 by vgears 3i and shaft 38 on which the is 5° out of phase with the arm 25. The maxi member 35 is slidably mounted. The clutch mem mum spacing of the contacts 23 and 21 is such ber 33 is freely mounted on shaft 33 but is re that just before that condition is reached the strained against axial movement. Surrounding shaft 3% is a stationary coil 39 and a ?eld frame 65 contact 24 engages, but, of course, the spacing may be vless. iii) of magnetic material. The clutch member 35 Conditions arise in use, particularly at the start and shaft are also of magnetic material and of the operation, When the disparity between the therefore when the coil 39 is energized the mem positions of the motion transmitting and receiv ber will be pulled into engagement with a fric tion surface, such as cork, on the member 33. 60 ing members will greatly exceed the range within which the system is self correcting and which Thus rotation of motor 35 will be communicated require perhaps one or more complete turns of through the clutch unit 315 to the shaft i3. the ?ne receiver and a partial turn of the coarse Three slip rings Ill, 62 and 63 on the shaft of receiver to be fed into the control differential to arm 23 are electrically connected respectively with the center contact 24 driven by coarse re (i5 bring the follower'member into positional agree ment with the transmitter member. It will be ceiver t, and the two contacts 26 and 2'! driven The third member of differential l2 actuates a di rectional control member H, in this case a mov by the shaft 9. Brushes contacting these slip rings connect with the windings of motor 36 through leads £55 and lit respectively. The seen that although both the coarse and ?ne re~ ceivers are turning over, the coarse receiver is in controlof the input to the differential l2, until common lead 416 includes a source of power All 70 the contacts 24, 26 and 21 are satis?ed and open and the coil 39 in series relation. It is apparent, therefore, that as the contact 21% touches either of contacts 23 and 2? the energizing circuit of motor 36 is closed to produce a torque in one direction or the other, and at the same time clutch 75 the circuit of the motor 36, but when the torque of this auxiliary motorbecomes zero the shaftt returns to'control of the ?ne receiver and the follow-up motor is thereby sensitively controlled to bring the follower member into exact syn 2,405,066 6 chronism, when the contacts I1, [9 and 20 are satis?ed and the circuit of the motor 13 is opened. In the servo-motor control shown in Fig. 2 the - 1. A position reproducing mechanism compris ing coarse and ?ne receivers of a self synchronous contacts I9 and 20 are mounted on an arm 48 transmission system having a predetermined ratio extending from a shaft 49 mounted in axial align ment with the shaft on which the contact I? is mounted. The shaft 49 carries a pinion 55 mesh I claim: of relative movement, a servo-motor, an ener sizing circuit for the servo-motor including a mov able contact, operating means for the movable ing with a gear 5| on a shaft 52, The shaft 52 contact having a yieldable drive connection with has secured to it an arm 53 to the end of which and biased to a de?nite angular relation to the centralizing springs 54 are attached. The shaft 10 ?ne receiver, a response connection from the 49 also carries’ a gear 55 which-meshes with a servo-motor operative to neutralize the effect of pinion 56 connected to drive a drag disc 57. The the operating means upon the movable contact. drag disc is shown as running in a chamber 58 a pair of movable contactable elements one ?lled with a liquid such as oil, but any form of coupled to be driven by the coarse receiver and drag device may be employed. The gear 55 carries the other coupled to be driven in the same direc a pin 59 adapted to engage a ?xed pin 60 and tion by the contact operating means at the said thereby limit the rotation of gear 55 and arm 48 predetermined ratio of movement thereto, the carrying the contacts [9 and 20. said elements being positioned a de?nite distance With this form, of servo-motor control the cen out of contact when the contact operating means tralizing springs 54 will maintain the contacts is in its biased relation to the ?ne receiver, and l9 and 20 in a ?xed position during normal oper means actuated by the engagement of the con ation, that is, when the response represented by tactable elements for supplementing the bias of shaft [6 remains synchronized with the signal the operating means. represented by shaft II. If for any reason the 2. A position reproducing mechanism compris response, represented by shaft It, does not agree ing coarse and ?ne receivers of a self synchronous with the signal represented by shaft II, the transmission system having a predetermined contact I‘! will displace the contacts [9 and 29 ratio of relative movement, a servo-motor, an against the centralizing effect of the springs 54. energizing circuit for the servo-motor including This displacement may correspond to several a movable contact, operating means for the mov turns of the ?ne receiver motor 5 and is only 30 able contact, drive means yieldably connecting limited by the stop pins 59 and 60. It will be seen the contact operating means and the ?ne receiver that the receiver motor 5 will remain in direct and including a cam and a spring pressed follower control of the drive 9 even though the response biasing the parts to a de?nite angular relation may differ from the signal by an amount repre and operative to reverse the angular direction of sented by several turns of receiver 5. It will also be seen that the contact 24 will remain centered between the contacts 25 and 21 during the ac cumulation of this difference. When the stop pins 59 and 60 come into contact and stop the movement of contacts is and 29, contact I‘! is also stopped and shaft 9 is forced from its biased position relative to receiver 5 until contact 24 engages either contact 26 or 2"! and the motor 35 comes into action as explained in connection with Fig. 1. When contacts l9 and 29 are thus displaced bias when a limited departure from biased rela~ tion is exceeded, a response connection from the servo-motor operative to neutralize the effect of the operating means upon the movable contact. a pair of movable contactable elements one cou pled to be driven by the coarse receiver and the other coupled to be driven in the same direction by the contact operating means at the said pre determined ratio of movement thereto, the said elements being positioned a de?nite distance out of contact when the contact operating means is in its biased relation to the ?ne receiver, and means actuated by the engagement of the contactable elements for applying a predominant bias to the operating means to prevent reversal. from their central position the centralizing force resulting from the springs 54 is substantially proportional to the displacement. As the re sponse from motor l3 causes contact I‘! to move 50 3. A position reproducing mechanism compris ing coarse and ?ne receivers of a self synchronous from its engaging contact the springs 54 will move transmission system having a predetermined ra the engaging contact toward the central posi tio of relative movement, a servo-motor, ener tion. This motion will be opposed by the drag gizing means for the servo-motor including a disc 51 so that the rate at which the contacts movable control member, operating means in return to their central position is proportional cluding a relief cam operatively connecting the to their displacement. The motor I3 can there rotor of the ?ne receiver with the control mem fore remove the error only at the rate at which ber, response means‘ operated by the servo-motor the contacts return to their central position. for neutralizing the action of the ?ne receiver During the return of the contacts l9 and 25 to their central position the shaft carrying contact (50 rotor upon the control member, a pair of con tacts movable in a common path, one coupled to I‘! is limited to the same rate. This shaft repre be driven by the coarse receiver and the other sents the error between the response from servo coupled to be driven in the same direction by motor i 3 and the receiver 5 and therefore the the control member operating means at the said error can only be removed at a rate which is de predetermined ratio of movement thereto, the termined as a function of the displacement, that said pair of contacts being spaced a de?nite dis is, of the error. tance when the ?ne receiver rotor and the control This speed control in attaining synchronism is member operating means are in synchronism, the the subject matter of my copending application relief cam permittingdeparture from synchro Serial No. 432,237. nism su?'iciently to allow the pair of contacts to It is obvious that the principle exempli?ed in engage, an auxiliary motor, an energizing cir the illustrated embodiments of the invention may cuit for the auxiliary motor including the pair be otherwise applied without departing from the scope of the invention as de?ned in the follow—_ ing claims. 75 of contacts, and means operatively connecting the auxiliary motor to the control member operating. means. ' 2,405,066 8 bias of the operating means when the relative 4:. A position reproducing mechanism compris movement of the control elements exceeds a pre ing coarse and ?ne receivers of a self synchronous determined amount. transmission system having a predetermined ra 7. A position reproducing mechanism com tio of relative movement, a servo-motor, energiz prising coarse and ?ne receivers of a self syn Cr ing means for the servo-motor including a mov chronous transmission system having a prede able control member, operating means including termined ratio of relative movement, a servo motor, energizing means for the servo-motor in a relief cam operatively connecting the rotor of the fine receiver with the, control member, re sponse means operated by the servo-motor ior neutralizing :le action of the ?ne receiver rotor cluding two relatively movable, cooperative con trol members, operating means for one of the movable control members having a yieldable drive upon the control member, a pair of contacts connection with and biased to a de?nite angular relation to the ?ne receiver, a response connec movable in a common path, one coupled to be driven by the coarse receiver and the other tion from the servo-motor to the said movable control member, the second movable control member being adjustably mounted, means bias coupled to be driven in the same direction by the control member operating means at the said pres determined ratio of movement thereto, the said pair of contacts being spaced a de?nite distance ing the adjustable control member toward a position to e?ect positional agreement between when the ?ne receiver rotor and the control mem the operating means and the servo-motor, means to retard the return movement of the biased member from a displaced position, the control ber operating means are in synchronism, the re lief cam permitting departure from synchronism sufficiently to allow the pair of contacts to en~ members coacting to displace the adjustable gage, an auxiliary motor, an energizing circuit member an amount proportional to the error for the auxiliary motor including the pair of: contacts, means operatively connecting the au::— in positional agreement between the operating means and the servo-motor, a pair of relatively iliary motor to the control member operating movable control elements coupled to be relatively moved by the coarse receiver and the control means, a normally open clutch in the said con~ necting means, and means controlled by the said pair of contacts for closing the clutch, member operating means at the said predeter mined ratio of relative movement, and means actuated by the pair of control elements for sup plementing the bias of the operating means when the relative movement of the control elements exceeds a predetermined amount. 8. A position reproducing mechanism com prising coarse and ?ne receivers of a self syn chronous transmission system having a prede 5. A position reproducing mechanism compris ing coarse and fine receivers of a self synchro nous transmission system having a predeter mined ratio of relative movement, a' servo-motor, energizing means for the servo-motor including a movable control member, operating means for the control member, a relief drive connecting the control member operating means and the termined ratio of relative movement, a servo— rotor of the ?ne receiver and including a cam motor, means for energizing the servo-motor in and a spring pressed follower biasing the said cluding primary and secondary contacts, oper operating means and rotor to a de?nite angular ating means having a yieldable drive connection relationship at which the movable control mem» 40 with and biased to a de?nite angular relation to her is synchronized with the said rotor and yield the ?ne receiver, a response connection from the able to permit departure from synchronism, re servo-motor coacting with the operating means to sponse means operated by the servo-r ,o'tor for position the primary contact, a pair of movable neutralizing the action of the ?ne receiver rotor contactable elements one coupled to be driven upon the control member, a pair of contacts mov by the coarse receiver and the other coupled to able in a common path, one coupled to be driv “ be driven in the same direction by the operating by the coarse receiver and the other coupled to means at the said predetermined ratio of move be driven in the same direction by the control ment thereto, the said elements being positioned member operating means at the said predeter a de?nite distance out of contact when the oper mined ratio of movement thereto, the said pair 5 U ating means is in its biased relation to the ?ne of contacts being spaced a de?nite distance W11 .3. receiver, means actuated by the engagement of the ?ne receiver rotor and the control mern 1 the contactable elements for supplementing the operating means are in synchronism, where bias of the operating means, the secondary con the contacts may engage as the yieldable p tact being yieldably biased to open contact rela permit departure from synchronism, an auxil tion to the primary contact when the operating motor, an energizing circuit for the an“ iary 1r tor including the pair of contacts, and m means, and the response connection are in posi . operatively connecting the auxiliary motor to the contact operating means. 6. A position reproducing mechanism com prising coarse and ?ne receivers of a self-syn chronous transmission system having a predee termined ratio of relative movement, a servo— motor, energizing means for the servo-motor in cluding a movable control member, operating means for the movable control member having a yieldable drive connection with and biased to a de?nite angular relation to the ?ne receiver and having a response connection from the servo motor, a pair of relatively movable control ele ments coupled to be relatively moved by the coarse receiver and the control member operat ing means at the said predetermined ratio of relative movement, and means actuated by the pair of control elements for supplementing the tional agreement, the two contacts coacting to effect a displacement of the secondary contact 60 an amount proportional to an error in said posi tional agreement, and means to retard the re turn of the secondary contact to the biased posi~ tion when displaced therefrom. 9. A position reproducing mechanism com prising coarse and ?ne receivers of a self syn chronous transmission system having a prede termined ratio of relative movement, control op erating means having a yieldable drive connec tion with and biased to a de?nite angular rela tion to the ?ne receiver, a, pair of relatively mov able control elements coupled to be relatively moved by the coarse receiver and the control op erating means at the said predetermined ratio of relative movement, means actuated by the pair of control elements for supplementing the bias 2,405,066 of the control operating means when the relative movement of the control elements exceeds a predetermined amount, a servo-motor operably connected to drive a response shaft, means di?erentially connecting the control operating means and the response shaft to actuate a con trol for the servo-motor to bring the response shaft into angular agreement with the control 10 operating means, and means associated with the control for the servo-motor effective to cause the servo-motor to bring the response shaft into angular agreement with the control operating means at a rate which is a function of the lack of angular agreement of the response shaft with the control operating means. JAMES D. TEAR.