US2405629A - Remote control apparatus with unidirectional stopping - Google Patents

Description

Aug. 13, 1946. M, N, YARDEVNY REMOTE CONTROL APPARATUS WITH UNI-DIRECTIONAL- STOPPING Filed Feb. 9, 1945 Mex/1 MYA RDE/Vy INVENTOR ATTORN EY Patented Aug.'l3, 1946 REMOTE CONTROL APPARATUS wrm UnmmEc'noNAL STOPPING Michel N. Yarden New York, N. Y. Application February 9, 1945, Serial No. 576,920 7 Claims. v (01. 172-239) 1 This invention relates to control apparatus for energizing a motor, which may be at a remote point, to move an object or load to a predetermined position. The motor in such systems may be, and usually is, reversible so that the object or load may be moved in either direction.

In virtually all mechanical or .mechanicalelectrical devices, including remote control apparatus to which this invention pertains, there is an inherent over-run beyond the ideal or normal stopping position due to mechanical and electrical inertia, back-lash in gears and other parts, wear in bearings and other engaging surfac etc. In devices which are reversible and operate in either direction, there is ordinarily a right over-run when the device is stopped while operating in a rightward direction and a "left over-run when stopped while operating in a leftward direction. Ordinarily, all other things being the same the right and left over-runs are equal, so that, calling each of the two over-runs, a directional over-run," there are two directional over-runs. That is to say, in a reversible device which is sometimes operated in a rightward direction, and sometimes in a leftward direction, and is stopped in either direction, there will be present an extent of over-run equal to two directional over-runs.

The prime object of this invention is to increase the accuracy of control apparatus, i. e., to decrease the deviation between the ideal or theoretical stopping position which would always be attained by a theoretical apparatus, load and other parts without weight, inertia, friction, etc., on one hand and the actual stopping position of the physical apparatus and load, subject to the directional over-runs pointed out above on the other hand. These and kindred objects are attained by providing means in control apparatus, which is reversible for moving the load in either direction, for reducing the extent of overrun by eliminating either the aforementioned "right over-run or the left over-run; by so eliminating one or the other of the two "directional over-runs the accuracy of the apparatus is increased twofold and by the same token the error is reduced in half. This is achieved, as will be fully described in the specification, by causing the device whether operating in a rightward (or clockwise) or a leftward (or counterclockwise) dlrection, to always stop in a predetermined direction, which may be either 'clockwise or counter-clockwise as may be determined beforehand. Assuming that the predetermined direction of stopping is clockwise-which happens to be the direction illustrated in the drawing and described in the specification-then there will be present'a device, adapted whether operating clockwise or counter, to stop when comin .from' a predetermined direction, to wit, clockwise, as assumed.

For the attainment of this object and such other objects as may appear or be pointed out herein, I have shown an embodiment of my invention in the accompanying drawing, wherein:

Fig. 1 is a diagrammatic illustration of the improved remote control apparatus implemented with the uni-directional stopping provision of the invention;

Fig.' 2 is a detail, partly in section, of the improved stopping provision;

Figs. 3A to 3D illustrate sequential operation of the device;

Fig. 4 illustrates a slight modification in operation of the improved stoppin device; and

Fig. 5 is a diagrammatic illustration of a selector disc showing the various stopping and reversal positions of the contact arm.

The remote control apparatus shown in Fig, 1 has two selectors I, II, although so far as the invention is concerned, it may have one or more than two. Each of the selectors I, (II) has an insulated disc 18 (38) and (rotatively mounted on a shaft 5!) provided with a pair of segments I6, I! (38, 31) the adjacent ends of which are separated by gaps i9 (39). Each of the selectors I (II) has a contact arm H (3|) secured to rotate with the said shaft 5| and provided at its distal end with a. contact II (3i slidably engageable with the said segments IS, IT (36, 31). The segment is of selector I is connected in a manner to permit rotation of the discs (conveniently shown by a flexible lead IG to lead l4 having a switch 12, which connects to the outside of a relay 24; the other segment i! of selector I is connected by flexible cable and lead I5 having a switch l3, to the outside terminal of a relay 25. In similar manner, the outside terminals of the two said relays 24, 25 are connected to the segments, 36, 31, of the selector II, through leads, respectively, 34, having respective switches 32, 33. The inner terminals of the relays 24, 25 are connected by short leads 24 25 to a common wire 23 leading through switch 22 to one terminal 2! of a source of supply.

The aforesaid switches l2, [.3 are connected for unison operation by a gang switch A while the corresponding switches 32, 33 of selector II has a gang switch A. Either one ofthe selectors I, II is placed into operation by closing their respective gang switch A, A and at the same time opening the switches of the selector not in operation. Assuming that selector I is to be placed in operation to move the load. driven from shaft 5| as shown ln'the drawing, in a clockwise direction, insulated disc I8 is pre-set by rotational adjustment in clockwise direction to displace gap I9 from the normal or zero position (which is taken to be at 12:00 o'clock as shown in selector II) an extent which will move the load to the desired position and switches I2, I 3 are closed.

This pre-setting of disc I 8, will cause contact arm II to be in engagement with segment I5, as

, shown in Fig. 1. When it is desired to move the load to the predetermined position corresponding to the setting of selector I, the switch 58, 22 are closed to complete a circuit which may be traced from terminal 59 through wire 51, lead 51 to contact arm contact and engaged segment l8, through flexible lead 86 lead l4, closed switch l2, to relay 24, from whence through short lead 24 to wire 23, leading back to the other terminal 2|. Energization of relay 24, causes this relay to attract its armature 44, to complete a circuit to the motor winding 46, which may be traced from the aforesaid supply wire 28, through lead 28, to relay contact 28, attracted armature 44, common lead 40, unattracted armature 45, of the other relay 25, (which is deenergized), to relay contact 43, and through lead 41, to motor winding 48, from whence the circuit may be traced through short lead 50', through the armature of motor 50, other short lead 50 leading to a rotary speed governor which will be subsequently more fully described; at this time it might be stated that the circuit be traced as completed through the said supply wire 51, leading back to the other terminal 59. Energization of field winding 48, causes rotation of load motor 55 in its clockwise direction, which rotation continues until contact arm H. which is secured to rotate with motor shaft 5| in the same clockwise direction, reaches gap IS, in the aforesaid precept position of insulated disc l8, whereas the gap I9 is bridged, so that contact engages both segments l5, l1, to energize both relays 24, 25, with the result that their respective armatures 44, 45 are attracted and open the circuit through th field windings, causing the motor to stop.

The aforementioned rotary governor, is provided for the purpose of holding down the motor speed to a predetermined amount for the purpose which will become apparent from the following description, and comprises an insulated disc 52, which is mounted to rotate with motor shaft 5|, and comprises a swing arm 55. The arm is pivotally mounted on the disc at one end 55a, and is weighed at its distal end, and is also provided with a contact 55 at its distal end, engageable with a contact 54, on the disc 52; the pivoted end of spring arm 55 is connected to a collector ring 55, engaged by a brush 56 which is on the supply wire 51. The fixed contact 54 is connected to a second collector ring 53, which is engaged by a brush 53 which is on the short lead 55 leading to the motor armature circuit. Spring arm 55 is preferably made of spring material which normally presses the arm to engage its contact 55 to engagement with the stationary contact 54, to complete a circuit which may be traced from the short lead 58 coming from the motor armature to brush 53 collector ring 53, fixed contact 54, spring arm 55 and to the collector ring 56, from whence through the brush 56 to Supp y wire 51,

back to current source. When motor speed exceeds a predetermined amount, the spring arm 55 under the influence of increasing centrifugal force, will move outwardly to cause its contact 55 to break engagement with fixed contact 54, thus breaking the motor circuit and causing the motor vided with a contact 12 at its distal end. Switch arm 12 is maintained during the normal running of motor 5|l-by means which will soon be described-in engagement with a contact 82 provided at the distal end of a second lever switch arm 82, connected by lead 83 to the supply wire 51. Hence in the normal running of the motor, the two switch arms 12, 82 making contact with one another as mentioned, the rotary speed governor will baby-passed and ineffective to influence motor speed. The rotary governor comes into operation when the motor is to be stopped as the load approaches its predetermined end position, in the following manner:

There is provided on motor shaft 5|, as may be seen from Fig. 1 and also from Fig. 2, two discs 88 and 10, both of which are free to rotate on a reduced portion 5| X of motor shaft 5|. Between the discs 10, is provided a washer 2 which is feathered to the reduced shaft portion 5| for a slight extent of axial movement. A spring coil 3, one end of which bears against the left shoulder (as viewed in Fig. 2) formed by the aforesaid reduced shaft portion 5| the other end of spring 3 abutting against the assembly of disc 80, washer 2, and disc 10, thelatter disc bearing against a collar 4 formed on shaft 5|. The disc 80 has a radially extended finger BI, and the disc 10 has a similar finger designated 1|. The discs 15, 80 are positioned on shaft 5| in a manner to interpose finger 8| of disc 80 between the distal end of lever switch arm 82 and a stationary stop I secured to machine frame, as is clearly shown in Fig. 1 and also seen in an of the Figs. 3A to 3D; and with the finger 8| of the other disc 80 positioned to permit the disc to swing from a position in which its finger 1| abuts the distal end of the other lever switch arm 12 (which position is shown in Fig. l and also Fig. 3A), to a second position which is, as shown in the drawing, about 60 less than a full circle from the first position and in which second position the finger 1| of disc 10 abuts the other side of the aforesaid stationary stop l, as shown in Fig. 30. Thus, the rotation of disc 80 is restrained to a small angle of turning by reason of the interposition of its finger 8| between stop I and the lever switch arm 82, whereas the disc 10 has a much larger angle of rotation somewhat less than a full circle, from the position shown in Fig. 1, with its finger 1| abutting lever switch arm 12, counter-clockwise, to a second position in which the finger abuts with the stop I, as shown in Fig. 3C.

By reason of the mounting of the discs 15, 80 on the shaft 5|, as described above with particular reference to Fig. 2, both discs are frictionally driven by motor shaft 5|, in the particular direction of motor rotation. It has been noted in the statement of invention, that the provisions for uni-directional stopping has been designed to provide for stopping th motor, irrespective of whether the motor is operating in a rightward (or clockwise) or a leftward (or counter-clockwise) direction-at all times in a clockwise direction. Fig. 3A represents the position or the parts, more particularly the discs 10, 80 and the lever switch arms 12, 82, when the motor rotates in a clockwise direction. By reason of the frictional engagement between the discs 10, 80, the keyed washer 2, and shaft collar 4, the discs I0, 80 will likewise be both turned in a clockwise direction to bring finger ill of disc 80 in abutment with stop I, and to bring finger II of disc 10, into abutment with distal end of lever switch arm 12, moving its distal contact into engagement with the distal contact 82 01 the other lever switch arm 82, causing both lever arms 12, 82 to be turned in a clockwise direction, which turning is restrained by the stop 82', abutted by the lever switch arm 82. In this condition of the parts as shown in Fig. 3A, it will be noted that the aforesaid abutment of finger II with the two lever switch arms 12, 82, causes the by-pass circuit previously traced to be completed and thus to eflectively by-pass the rotary speed governor. Summarizing, during the normal rotation of the motor in clockwise directlon, the rotary speed governor will be bypassed so as not to affect the motor speed. We will assume that the load is now approaching the desired end position, making it necessary to stop the rotation of the motor, and also that selector I is in operation. From Fig. 1 it will be noted that during the said clockwise rotation of the motor, contact arm I I is in engagement with se ment I6 of the insulated disc i8, (which has been preset, as already described, to displace 'gap I9 the proper angular extent away from the zero position, depending upon the particular load movement desired). As previously described, the engagement of contact arm II with segment I6 causes the clockwise rotation of the motor by reason of the energization of relay 24 and field winding 48. As the load is approaching the desired end position, contact arm II will approach the gap I9. Ideally, motor rotation should cease immediately when contact arm I I reaches gap I9, to bring its contact II into engagement with both segments I6, I! to energize both relays 24, 25 and disrupt the current supply to the motor, in the manner already described, and stop motor rotation.

However, due principally to inertia and also for the reasons mentioned in the statement or invention, contact arm II will ordinarily not stop precisely at gap I9, but will over-run this position to an extent causing its contact I I to leave engagement with the posterior segment I and to make engagement solely with the anterior segment I1,

thus causing the deenergization of relay 24 and energization of relay 25. This causes the motor to again rotate but in the reverse or counterclockwise direction. This reversal in direction, shown in Fig. 3B, results in the turning of both discs I0, 80 counter-clockwise, with finger 8I of disc 80 moving away from stop I and with finger II of disc 10 moving away from lever switch arm I2. However, almost immediately-more specifically, after moving a small portion 01 a complete revolution, as shown in the drawingfinger 8| 0! disc 80 abuts the distal end of lever switch arm 82 to move its and also the other arm 12, their contacts 82 12* being engaged, in a clockwise direction until lever switch arm I2 abuts its stop I2, to bring the parts in the position shown in Fig. 33. From Fig. 33 it will be seen that, upon before the parts can be moved from their position shown in Fig. 3A to positions shown in Fig. 33), so that the speed governor continues to be bypassed. Hence in instances when the motor rotates (normally, as distinguished from rotation after a reversal. as will be seen) in a clockwise direction, and as the load approaches its end position, contact arm II in approaching gap I9 overruns to cause a reversal of rotation from clockwise to counter-clockwise, the speed governor will continue to be by-passed with the result that there is no reduction in speed.

It should be noted that Fig. 3B shows the condition of the parts soon after a reversal irom clockwise to counter-clockwise, and with the contacts 12 82 by-passing the speed governor as alreadydescribed. Disc 10 continues to turn with the counter-clockwise rotation of shaft 5| until its finger II, after traversing almost a complete revolution, abuts the stop I as shown in Fig. 3C, the contacts 12 82 remaining engaged to bypass the governor, as shown.

The extent of over-run or contact arm II beyond gap I9 and onto anterior segment I! will not always be the same but will vary (depending upon motor speed principally, but also influenced by the condition of the parts as afiected by wear and other factors), sometimes being close to the gap and at other times being further removed therefrom. But for purposes of description, it may be assumed that the contact arm-when rotating, say, clockwise as shown by arc-arrow a in Fig. 5- will over-run a certain average extent onto the anterior segment, which for convenience will be referred to as the over-run position, and which is shown in Fig. 5 by the radial line A.

As the result or said reversal, the contact arm II over-run onto segment I1, will now be turned by motor shaft 5| counter-clockwise (as shown by the arc-arrow b in Fig. 5), now approaching gap I9 from the opposit direction, 1. e., from segment I1 rather than from segment I6, as before. At the start of this counter-clockwise turning, from the said over-run position on segment H, the discs 10, and lever switch arms 12, 82 will be in the positions shown in Fig. 30, still causing the speed governor to be by-passed. When contact arm II reaches and bridges gap I9, both relays 23, 25 will again be energized to disrupt current supply to the motor, as happened in th first bridging of the gap when contact arm II approached the gap from segment IS. The arm will again over-run from the posterior segment I! onto the anterior segment I6, for the same reason and, on the average, to the same extent a the first over-run; this over-run position is shown in Fig. 5 by the radial line B. It should be stressed that the extent of the first A and second B overrun is, on the average, the same inasmuch as there has (as yet) been no speed reduction, the speed governor continuing to be by-passed (which can be seen by comparing Fig. 36 with Fig, 3A).

As the result of the second reversal (from counter-clockwise to clockwise), contact arm II, over-run onto segment IE, will now be turned by motor shaft clockwise, now approaching gap I9 from the segment I6 as shown by the arc-arrow I c in Fig. 5. We have already considered a situation, at the beginning of the cycle now being described, in which motor rotation was clockwise and contact arm II approached gap I9 from segment I6, and we had seen that the position of the the reversal in direction irom clockwise to coun- 76 part prior to the first reversal (from clockwise asoaoce to counter-clockwise) was as shown in Fig. 3A with finger 8i of disc 88 abutting stop 5 and with finger 1| of disc I8 pushing the lever switch arm I2 into contact with lever arm 82 against its stop 82'. We have also seen that the parts are in the position shown in Fig. 30 prior to the second reversal (from counter-clockwise to clockwise) with finger SI of disc 80 now pushing the lever switch arm 82 into contact with lever arm I2 against its stop l2 and with finger II of disc 10 now abutting the stop i. This diiference between the position of the parts-especially the dlflerence in position of disc III-prior to the first reversal (clockwise to counter-clockwise) as shown in Fig. 3A, and their positions prior to the second .reversal (from counter-clockwise back to clockwise) is important since upon that difference hinges the gist of the invention. It will be seen from Fig. 3A that it is finger II of disc 18 which maintains the lever switch arms I2, 82 engaged in contact (while finger 8| of disc 88 abuts stop I); it will be seen from Fig. 30 that it is finger 8| of the other disc 80 which now maintains the lever switch arms engaged in contact (while finger II of disc III now abuts stop I). And it will b seen from both Figs. 3A and 30 that the finger M and disc 80 has a limited small angular extent of movement between stop I and the lever switch arm 82 (which limited angle is designated S in Fig. 33), while the finger II and disc 18 has a considerable angular extent of movement between stop I and lever switch arm I2 (which considerable large angle is designated Lin Fig. 3A).

Hence at the time of the first reversal which occurs when the contact arm is engaged with segment I1 and causes a reversal to a counter-clockwise rotation, finger 8| has only to traverse a small angle S before it reaches the lever switch arms to continue their engagement in contact (which prior to the reversal were maintained in contact by the finger II). On the other hand,

- at the time of the second reversal, which occurs when the contact arm is engaged with segment I6 and causes a reversal to clockwise rotation,

finger Ii must traverse the considerably larger angle L before it reaches the lever switch arms to continue their contact engagement (which prior to the reversal were maintained in contact by th finger BI, see Fig. 30). During virtually all of the time required for disc 10 to traverse the large angle L, the lever switch arms 12, 82 will be in open condition, as shown in Fig. 3D.

It should be mentioned at this point that the lever switch arms I2, 82 are either pivotally mounted at one end and spring-pressed apart and into engagement with their respective stops i2, 82' or are rigidly mounted at one end but formed of flexible material and urged apart by the springy natur of the lever material. case, if neither one of the fingers II, I2 abut the lever switch, arms-which is the circumstance in Fig. 3D-the arms are separated and not in contact engagement (see Fig. 3D).

As motor rotation reverses, at the said second reversal, from counter-clockwise (see Fig. 30) to clockwise (see Fig. 3D), finger 8I moves clockwise away from abutment with switch arm 82 toward stop I and the switch arms are urged by the afore-described spring provision to disengag (as shown in Fig. 3D) and open the governor by-pass circuit. The switch arms I2, 82 remain in their disengaged position against their respective stops I2, 82' (as shown in Fig. 3D), during the time that disc 10 takes to traverse the large angle L, Fig. 3A, from its abutment with stop I, as shown in Fig. 30, around almost a complete revolution,

In either to abutment with switch arm I2 (as shown in Fig. 3A). Hence during this time, the speed governor is not by-passed but is effective to reduce the motor speed. It will be noted that, in the situation considered in Fig. 5, contact arm II makes three traverses, namely, first, a clockwise traverse, designated a, following normal motor rotation in clockwise direction; second, a counterclockwise traverse, designated b, following first reversal; third, 9. final traverse in a clockwise direction designated 0 following second reversal. The speed of the second traverse b is very considerably reduced from that obtaining during the first traverse a by reason of the fact that upon a the motor reversal-which means that th motor comes to a standstill from which it acceleratesthe rotational speed to which it accelerate during the said second traverse speed is relatively low by reason of the briefnes of the time period of said traverse after reversal. The speed of motor rotation is even lower during the third traverse c by reason of this circumstance and also by reason of the fact that the speed governor comes into operation at the said third traverse c, as already described. Hence, contact arm will not over-run onto segment II, but will stop at the gap I8, which position is indicated in Fig. 5 by the radial line C.

It is interesting to note from Fig. 5 that the aforedescribed over-runs of the contact arms, as the device is brought to a stop in a clockwise direction (short arrow-arc c)which direction is chosen as the uni-directional stopping direction after normal rotation in a clockwise direction (long arrow-arc a)-traces a Z-like movement, i. e., following the strokes and directions in customarily writing this letter; the first top stroke from left to right is the arrow-arc a, the second diagonal stroke from right to left is the arrow-arc b, and the final bottom stroke from left to right is the arrow-arc c.

A less complicated movement is traced by the contact arm in over-running following normal rotation in a. counter-clockwise direction, which comprises only two of the three arrow-arcs a, b, 0, making up the so-called Z-effect when stopping after normal clockwise rotation; these two arrow-arcs are b (which first component is not truly accurately represented by inter-segmental arrow-arc b, but rather by the longer arrow-arc b, signifying that the reversal--at B-occurs after rotating normally in the counter-clockwise direction shown), and the final uni-directional stopping arrow-arc c. Uni-directional stopping after normal counter-clockwise rotation, therefore, involves only a single reversal, namely, at B. The discs I0, 88 are in the positions shown in Fig. 3C just prior to this reversal; upon reversal from counter-clockwise (Fig. 30) to clockwise (Fig. 3D) disc I0 traverses the large angle L, see Fig. 3A, the governor by-pass circuit remaining open at this timeas shown in Fig. 3D--to reduce the speed, as already described in connection with the Z-eflect when stopping after normal clockwise rotation.

The stop 82' of switch arm 82 prevents finger 1| when its disc I8 is turned clockwise, as shown in Fig. 3A, from pushing switch arms I2 and 82 in abutment with the other finger 8|, which is thus free to leave abutment with switch arm 82 and traverse the small angle S, Fig. 3B, alone. The consequence of this is that for a very short period the contacts 'I2 82 will be open when there is a. reversal from clockwise (Fig. 3A) to counter-clockwise (Fig. 33), since finger II leaves abutment'with its switch arm 12 which will immediately disengage from switch arm 82 by its spring action, Fig. 3A, before the other finger 8i,

leaving abutment with stop I, reaches its switch arm 82, to bring the contacts 12 82 into en- Basement again.

If this short interval or reduced speed is not desired, the stop 82' of switch arm 82 may be omitted, as has been done in Fig. 4, in which case finger H pushes the switch arm 12, 82 against the other finger 8i which abuts stop I, as shown. Hence, upon a reversal fromthe clockwise rotation shown in Fig. 4, the engagement between contacts 82 I2 is never broken and the normal by-passing oi the speed governor is not interfeud with.

I claim:

1. In control apparatus for moving a load in a desired direction to a desired end position, in combination, a pair oi relatively movable members, one of the members having a pair of electrical conducting elements separated by a gap, the other member having a contact element engageable with the said conducting elements, a

motor operatively connected through a shaft to drive the load, a pair 01' coils associated therewith, individual ones thereoi' being connected to respective ones of the said pair of conducting elements, one of the said pair of members being selectively adjusted to cause displacement between said gap and contact element on engagement thereof with one or the other of the said pair 01' conducting elements to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction, say, clockwise, the other of the said pair of members being turned by the motor in a direction to cause alignment of contact element and gap to stop the motor, and means operative irrespective of the direction of said operational load movement to cause said motor stopping to occur after a short terminal movement of the said load shaft in a predetermined direction, say, clockwise, comprising a speed governor adapted to hold the speed oi! motor rotation to a reduced limit, a circuit including a switch for by-passing the speed governor in the closed condition of the switch, said switch comprising a pair of arms each mounted at one end and spring urged apart, each arm being provided with a contact at its distal end, each arm having a stop limiting said parting movement, a pair of discs rotatively mounted on the said load shaft and frictionally constrained to partake of the rotation thereof, a finger stop disposed close to, but spaced from, the contact end of a first designated one of the said pair of switch arms, each of the said discs having a radial finger, the finger of a first designated disc being interposed between the adjacent side of said finger stop and the contact end of said first switch arm whereby the said first disc whereby the speed governor is by-passed during operational rotation in the said clockwise direction; the said contact arm overrunning from the engaged posterior conducting element onto the anterior conducting element to cause a reversal in rotation from clockwise to counter-clockwise, whereat the first said finger turns counter-clockwise irom the said adjacent side of the finger stop to abut the contact end or the first said switch arm to engage its contact with the contact or the companion switch arm and to abut the latter arm against its said stop, whereby the speed governor is by-passed upon the said reversal, the second said finger abutting the ulterior side of the finger-stop; the said contact arm over-running from the engaged posterior conducting element onto the anterior conducting element to cause a second reversal in rotation from counter-clockwise to clockwise, whereat the first said finger turns clockwise from said abutment with the first said switch arm to release the arm to the said spring means to disengage the switch arm contacts, whereat the governor becomes eilfective to reduce motor speed following the said second reversal, the second said finger turning from said abutment with the ulterior side of the finger stop clockwise through the said relatively large angle before abutting the second said switch arm to re-engage the switch contacts, whereby the said contact arm turning at the said reduced speed stops at the gap without over-running.

2. In control apparatus for moving a load in a desired direction to a desired end position, in combination, a pair of relatively movable members, one of the members having a pair of electrical conducting elements separated by a gap, the other member having a contact element engageable with the said conducting elements, a motor operatively connected through a shaft to drive the load, a pair of coils associated therewith, individual ones thereof being connected to respective ones of the said pair of conducting elements, one of the said pair of members being selectivel adjusted to cause displacement between said gap and contact element and engagement thereof with one or the other of the said pair of conducting elements to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction, say, clockwise, the other of the said pair of members being turned by the motor in a direction to cause alignment of contact element and gap to stop the motor, means operative irrespective of the direction of said operational load movement to cause said motor stopping to occur after a short terminal movement of the said load shaft in a predetermined direction, say, clockwise, comprising a speed governor adapted to hold the speed of motor rotation to a reduced limit, a circuit including a switch for bypassing the speed governor in the closed condition of the switch, said switch comprising a pair of arms each mounted at one end and provided with a contact at its distal end, spring means urging the said pair of arms outwardly to open the switch, a pair of discs rotatively mounted 'on the said load shaft and frictionally constrained to partake of the rotation thereof, a stop disposed close to, but spaced from, the contact end of a first designated one of the said pair of switch large angle to the second one o! the saidpair of switch arms, the first said finger during the said operational clockwise rotation abutting the said finger stop and the second said finger abutting the contact end of the second switch arm to engage its contact with the contact of the companion switch arm and to abut the latter arm against the first said finger, whereby the speed governor is by-passed during operational rotation in the said clockwise direction; the said contact arm over-running from the engaged posterior conducting element onto the anterior conducting element to cause a reversal in rotation from clockwise to counter-clockwise, whereat the first said finger turns counter-clockwise from said adjacent side of the finger stop to abut the contact end of the first said switch arm to engage its contact; with the contact of the companion switch arm and to abut the latter arm against its said stop, whereby the speed governor is by-passed upon the said reversal, the second said finger abutting the ulterior side of the finger stop; the said contact arm over-running from the engaged posterior conducting element onto the anterior conducting element to cause a second reversal in rotation from counter-clockwise to clockwise, whereat the first said finger turns clockwise from said abutment with the first said switch arm to release the arm to the said spring means to disengage the switch arm contacts, whereat the governor becomes efiective to reduce motor speed following the said second reversal, the second said finger turning from said abutment with the ulterior side oi the finger stop clockwise through the said relatively large angle before abutting the second said switch arm to reengage the switch contacts, whereby the said contact arm turning at the said reduced speed stops at the gap without over-running.

3. In control apparatus for moving a load in a desired direction to a desired end position, in combination, a pair of relatively movable members, one of the members being provided with electrical conducting means having a neutral point, the other member having a contact element engageable with the said conducting means, drive means including a motor operatively connected through a shaft to move the load, a pair of coils associated therewith, individual ones thereof being connected to the said conducting means, one of the said pair of members being selectively adiusted to cause displacement between said neutral point and contact, element and engagement thereof with the said conducting means to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction, the other of the said pair of members being turned by the said drive mean in a direction to cause alignment of contact element and neutral point to stopthe said .drive means, means operative irrespective oi the direction of the said operational load movement to cause said stopping to occur after a short terminal movement of the said load shaft in a predetermined direction, comprising a speed governor adapted to hold the speed of motor rotation to a reduced limit,- a switch for by-passing the speed governor, a pair of discs rotatively mounted on the said load shaft and impositively adapted to partake of the rotation thereof, a stop disposed close to said switch, each of the said discs having a finger, the finger of a first designated disc being interposed between the jacent side of said stop and the said switch whereby the said first disc is limited to a relatively small angle of turning, the finger of theother disc being turnable with its disc from the ulterior side of the said finger stop through a relatively large angle to the said switch, the first said finger during the said operational rotation abutting the said stop and the second said finger abutting the said switch to by-pass the speed governor during operational rotation; the said contact arm ver-running from the engaged posterior conducting element onto the anterior conducting element to cause a reversal in rotation, whereat the first said finger turns from the said adjacent side of the finger stop to abut the said switch to continue said by-passing oi the speed governor, the second said finger abutting the ulterior side of the finger stop; the said contact arm overrunning from the engaged posterior conducting element onto the anterior conducting element to cause a second reversal in rotation, whereat the first said finger turns from said abutment with the said switch to render the said by-pass ineffective and the governor eii'ective to reduce motor speed following the said second reversal, the second said finger turning from said abutment with the ulterior side of the finger stop through the said relatively large angle before abutting the said switch, whereby the said contact arm turning at the said reduced speed stops at the neutral point without over-running.

4. In control apparatus for moving a load in a desired direction to a desired end position, in combination, a pair oi relatively movable members, one of the members being provided with electrical conducting means having a neutral point, the other member having a contact element engageable with the said conducting means, drive means including a motor operatively connected through a shaft to move the load, a pair of coils associated therewith, individual ones thereof being connected to the said conducting means, one of the said pair 01 members being selectively adjusted to cause displacement between said neutral point and contact, element and engagement thereof with the said conducting means to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction, the other of the said pair of members being turned by the said drive means in a direction to cause alignment of contact element and neutral point to stop the said drive means, means operative irrespective of the direction of said operational load movement to cause said stopping to occur after a short terminal movement of the said load shaft in a predetermined direction, comprising means to reduce speed of motor rotation, a switch for controlling the said speed reducing means, a pair of discs rotatively mounted on the said load shaft and impositively adapted to partake of the rotation thereof, a stop disposed close to said switch, each of the said discs having a finger of a first designated disc being interposed between the adjacent side of said stop and the said switch whereby the said first disc is limited to a relatively small angle of turning, the finger of the other disc being turnable with its disc from the ulterior side of the said finger stop through a relatively large angle to the said switch, the first said finger during the saidoperational rotation abutting the said stop and the second said finger enga in the said switch to render the speed reducing means inoperative during said operational rotation; the said contact arm overrunning from the engaged posterior conducting 13 finger stop to engage the said switch to maintain said speed reducing means inoperative, the second said finger abutting the ulterior side of the finger stop; the said contact arm over-running from the engaged posterior conducting element onto the anterior conducting element to cause a second reversal in rotation, whereat the first said finger turns from said engagement with the said switch to render the said speed reducing means operative to reduce motor speed following the said second reversal, the second said finger turning from said abutment with the ulterior side of the finger stop through the said relatively large angle before engaging the said switch, whereby the said contact arm turning at the said reduced speed stops at the neutral point without over-running.

5. In control apparatus for moving a load 1 a desired direction to a desired end position, in combination, drive means including a motor operatively connected through a shaft to move the load, means including a selectively adjusted member for controlling the said drive means to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction and to stop the said drive means with the load in the said desired end position, and means operative irrespective of the direction of said operational load movement to the finger o! a first designated disc being interposed between the adiacent side of said stop and the said switch whereby the said first disc is limited to a relatively small angle of turning, the

- 14 finger of the other disc being turnable with its disc from the ulterior side of the said finger stop through a relatively large angle to the said switch.

6. In control apparatus for moving a load in a desired direction to a desired end position, in combination, drive means including a motor for moving the load, means including a selectively adjusted member for controlling the said drive means to rotate the said motor in a direction to cause an operational movementof the load in a predetermined desired direction and to stop the said drive means with the load in the said desired end position, and means operative irrespective of the direction of said operational load movement to cause said stopping to occur after a short terminal movement of the motor in a predetermined direction, comprising means to reduce speed of motor rotation, and a switch means actuated by changes in direction of motor rotation for controlling the said speed reducing means.

7. In control apparatus for moving a load in a desired direction to a desired and position, in combination, drive means including a motor for moving the load, means including a selectively adjusted member for controlling the said drive means to rotate the said motor in a direction to cause an operational movement of the load in a predetermined desired direction and to stop the said drive means with the load in the said desired end position, means operative irrespective of the direction or said operational load movement to cause said stopping to occur after a short terminal movement of the motor in one predetermined direction, said latter means comprising means to change the speed of motor rotation, and a means actuated by changes in direction of motor rotation for controlling the said speed changing means.

MICHEL N. YARDENY.

Images