US2651714A - Selective point detector mechanism - Google Patents

Description

Sept. 1953 w. M. POOLE SELECTIVE POINT DETECTOR MECHANISM 2 SheetsSheet 1 Filed April 18, 1950 JINVENTOR.

MPoole HIS ATTORNEY Sept. 8, 1953 w, M, FLOOLE 2,651,714

SELECTIVE POINT DETECTOR MECHANISM Filed April 18, 1950 2 Sheets-Sheet 2 Fig? 2 I 5'9 INVENTOR. F Poole HIS A TTOIINE'Y Patented Sept. 8, 1953 SELECTIVE POINT DETECTOR MECHANISM William M. Poole, Aurora, 111., assignor to Westinghouse Air Pennsylvania Brake Company, a corporation of Application April 18, 1950, Serial No. 156,620

3 Claims.

My invention relates to a point detector mechanism for a circuit controller forming a part of a railway switch operating apparatus, and more particularly to a point detector mechanism for selectively controlling the indication contacts of the circuit controller.

Railway switch operating apparatus in which my novel point detector mechanism may be used to advantage normally comprises a motor controlled from a remote point to move the switch points of a railway switch from a normal position to a reverse position, and from the reverse position to the normal position. The apparatus also includes a circuit controller operated primarily by the operation of the switch motor with a point detector mechanism controlled by a point detector rod connected to the switch point, to control the indication contacts should the switch points fail to assume or remain locked in their normal or reverse positions for any reason.

In the point detector mechanism previously provided for switch operating apparatus of the type indicated above, the point detector rod cooperated with a rocker arm pivoted at its midpoint to a slidable short bar of the circuit controller. The rocker arm ends carried rollers which rode on the periphery of the point detector bar due to the bias of spring rods cooperating with the ends of the rocker arm, the rollers being adapted to be selectively received within a recess provided in the point detector rod when and only when the switch points were in their normal or reverse positions, The slidable short bar had pivoted to its other end an equalizer lever which cooperated through spring biased threaded rods and bell cranks with the movable contact fingers of the two pairs of indication contacts normally provided in the circuit controller. The movable contact fingers were also controlled by cams rotated by the operation of the switch motor. When and only when the switch points of the switch were in their normal or reverse position, would the point detector rod and the contact cams permit the pair of indication contacts corresponding to the position of the switch to close to set a clear signal for trafiic moving over the switch.

In the event of a trailed switch, the prior point detector mechanisms would be operated by the movement of the point detector rod to open the closed pair of indication contacts to set a restrictive signal for trafiic moving over the trailed switch. The prior point detector mechanism was such, however, that in the event of a trailed switch, the equalizer lever of the mechanism would be tilted to open either pair of the indication contacts remaining closed. Thus, the previous point detector mechanisms would open either pair of the indication contacts, but the operation of these indication contacts would not 2 show which one of the two switch points was displaced.

The object of my invention is, therefore, to provide a point detector mechanism for a circuit controller of a railway switch operating apparatus which will selectively control the indication contacts of the circuit controller.

A further object of my invention is to provide a selective point detector mechanism which may readily be made of existing non-selective point detector mechanisms by the addition of a few readily installed parts,

According to my invention, I provide a pivoted lever which cooperates with offset lugs fixed to the spring rods cooperating with the ends of the rocker arm. The contact cams and the point detector rod are unchanged in their cooperation in permitting the indication contacts of the circuit controller to close when and only when the switch points are locked in their norm-a1 or reverse positions. Should the switch be trailed, the resultant movement of the point detector rod will force one or the other of the rollers of the rocker arm out of the point detector rod recess to tilt the rocker arm. The movement of the rocker arm will move the spring rod and the associated offset lug to tilt the corresponding end of the pivoted lever. As will hereinafter be more fully described, a switch trailed in its normal position will cause the pivoted lever to open the normal indication contacts, while a switch trailed in its reverse position will cause the pivoted lever to open the reverse indication contacts.

Other objects and characteristic features of the invention will become apparent as the description proceeds.

I shall describe one form of a point detector mechanism embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a top plan view of a railway switch operated by a switch and lock movement incorporating a point detector mechanism embodying my invention. Fig. 2 is a top plan View of the circuit controller with the cover removed showing details of the point detector mechanism. Fig. 3 is a sectional view taken approximately along the line III1II of Fig. 2, while Fig. 4 is a schematic diagram of the point detector mechanism embodying the invention.

Similar reference characters refer to similar parts throughout the several views.

Referring to Fig. 1, the reference character A designates a railway switch comprising two fixed rails i and 2 and two movable switch points 3 and l. The fixed rails I and 2 are laid on tie plates 5 secured to the crossties 6 in the usual manner. The switch points 3 and 4 are interconnected by a front rod 1 and a head rod 8, and may be moved from the normal position illustrated to a reverse position by means 'of a switch and lock movement B which is of the type shown and described in Letters Patent of the United.

States No. 1,293,290 granted to William Zabel on February 4, 1919 for Railway TrafiicControllin Apparatus. The switch and lockmovement is connected with the head rod8 by a throwrod-Q and the usual switch basket thethrow rod'S extending under the fixed rail 2 and the switch point 4 and connected to the operating .barmot' shown) of the movement.

When the switch A occupies its normal position as illustrated in Fig. 1, the switch point 4 engages the 'fixed rail 2 while the switch point t is spaced a predetermined distance away from the fi-xed rail I. When-the switch is reversed'by the-operation of the switch and lockmovement B, the-switch point 'iengages'the-fixed rail! and the switch point '4 is spaced from the-fixed-rail 2.

The switch and lock-movement Bcomprises a casing -ll divided into three compartments, only one being illustrated. The compartments are provided with covers 12, i3 and Hi; the coveri'. closing the motor compartment, the cover 13 closing the gear reduction compartment, and the cover Hclosing the-circuit controller compartment [5 (Figs. 2 and 3). A look rod E6 and a point detector rod t1- arefixed by suitablemeans to the'front rod 1 and'passbeneath the fixed rail 2 to the'circuit controller compartment. The lock rod IBis of the usual form comprising two locking bars 18 and 9 (Figs. 1 and 3-). The locking bars are formed with notches in their upper and lower edges, only the lower edge notches 20 being illustrated in Fig. 3; the notches 20 being'engaged by a locking dog 2i forming a part or a lock box '22 when the switch is in its normal position and properlylocked. A second locking dog'23 is provided on the-lock-box for engaging'theupper notches formed in-the locking' barswhen the switch is'in its reverse position.

The lock box22 forms a part of aslide bar 24 reciprocated to its extreme right-hand position illustrated inFig. 3-bythe operation of the switch movement motor (not shown). The lock boxis provided at its right-hand-end with a rack 25, the teeth of which mesh with the teeth of'a pinion 'Z-GsuitabIy'mOunted within" the compartment [5. The rack '25 and the pinion 26 are shown in their extreme normal positions, the pinion '26 having been rotated in a counterclockwise direction by'movement of the lockbox and. rack fili'in-moving the switch points 3 and 4 to their normal position shown in Fig. 1. Reversing the switch points by operation-of theswitch and lock movement B through the throw rod 5 will atthe same time cause the slide bar 24 to move from right to left. The rack will accordingly'be moved in the same direction to rotate the pinion 2B in a clockwise direction. The movement of the lock box 22 will withdraw the locking dog 2i from the lower notches 25 in the locking bars 5-8 and It permittingzmovement of the locking bars in response 'to the reversal of the switch points, the locking dog 23 entering: the uppernotches of the locking bars at the end of the movement of the switch points to-lock the switch points in their reverse position.

The point detector rod 11 is of standard construction being circular in cross section and formed with an elongated peripheral notch 21' in that portion of 'the rod within the-:circuitcontroller compartment 15. The point-detector rod 'the pinion 2 6 which. acts is adapted to coact with elements of the circuit controller which will nowbedescribed.

The circuit controller comprises acamshait 28 journaled in a supporting framework 29 within the circuit controller compartment 15. The camshaft 28 has fixed thereto a gear 30 meshing with as an idler gear between the gear 30 and the rack 25. Movement of the .lock box 22 'by'the slide bar 24 when the switch points are moved .into their normal or reverse positions will accordingly rotate the gear 30 and .the. camshaft 28.

Mounted on and insulated from the camshaf 28 are four contact segments 3l-35. The contact segments 3| and 33 are disposed on one side of the gear 30 whilethe contact segments 32. and 34 are disposed on the other side of the gear. Each contact segment 3'l-'3'4 cooperatesat its periphery with two inwardly extending contact fingers "fixed to insulating strips "-2911 on the framework 29, the contact segments 3i and33 cooperating with-contactfingers'35, 3i and 39, tL respectively-and the contact segments 32:and 34 cooperating with contact fingers 86', .38 and 40, '42, respectively. The contact'segment 31 will attimes cooperate with the I contact fingers 6-5,: 31 to close a :contact 355- 31 thecontact seg- 1nent'33: with the contactfingers-SS, 4! to .elose a contact '3933-'4'l. Similarly, the contact segmentl32 will at times'close'a-contact36-32- st and-the contactsegmentflawill close. a contact il'34--'=42. The periphery of each cam segment may have any desired length,.and-the cain:segments :are secured to thecamshaft 28 in .any desired manner which will .permit angular displacement to any desired position-relativetothe camshaft. The contact segments herein illustrated are of'suchilengths and are sopositioned relative to the camshaft that rthe contacts 35- 3 li3'l. and?39-'33--4*|= are; closed: at all times except when the slideibar '24':is'in its extreme position illustrated in'Fig.:3 in whichthe switch pointsi3,J4:are'locked:in their normal position as illustrated, while thecontacts '26-32-38 and .40-f-3i4:--42 are closed: at all times except when the. slide; bar is in an. extreme left-hand position in Figg-Bzin which-the switch points.3 and dare locked in their reverse osition. The four sets of contactszdescribed may be used in a wellknown manner 'tocontrol the circuit for the switch. andilock. movement B, error other desired purposes.

Mounted: on theicamshaft 28. on oppositesides ofzthegear 30 are two cams'4'3 and 44. The cam '43 formed with azperipheral notch While the cam 44 is providedawith-a similarnotch '46 (Figs. 3 and 4). Associated with'thecams 43 and 44 are two pairs of oontact fingers 41 and 48, respectively;the'fingers 41 being interconnected'for simultaneousmovement by an insulating'bridge 49. and thefingers 48' being interconnected by an insulating bridge 50. The insulating bridges'are provided with dependent rollers 5|, '52, respectively, which coact' with the corresponding cams and form an actuating means for the respective contact fingers .when the cams are rotated.

Fixed to the'insulating strips 29a on the framework .29 are two pairs of'stationary contacts 53 and '54 (only one of each: being shown in Fig. 4), adaptedto be'engaged by the contact fingers 41 and-4B,,respectively. The contact fingers 41 and 48-will attimes assume inclined positions when the.notches 45, '46 of the camsare opposite the rollers 5|, 52, in which position the fingers 41 and 428.- willsengage. the stationary: contacts 53 and 54, respectively, as will hereinafter be more fully described. When the notches 45, 46 of the cams are not opposite the rollers 5|, 52, the contact fingers will be lifted to engage an upper stationary or shunting contact 55. The cams 43, 44 are so arranged and the notches 45, 45 are of such length that all of the contact fingers 41, 48 will be lifted when the slide bar 24 is in motion. One pair of contact fingers however will normally be permitted to assume their lower positions when the slide bar is in one extreme end of its movement, while the other pair of fingers will normally be permitted to assume their lower positions when the slide bar is in the other extreme end of its movement, as will be more fully described hereinafter.

Means are now provided to control the con tact fingers 41, 48 by the point detector rod I! when the switch A is trailed in its normal or reverse position.

To this end, there is provided a short bar 56 slidably received within guides 57 and movable longitudinally toward and away from the lefthand end of the circuit controller (Fig. 2). A lever 58 is pivoted to the inner end of the bar 56 and is provided with through openings near its outer ends to receive the ends of two threaded rods 59 and 60 with some clearance. The other ends of the threaded rods are pivotally connected to the dependent arms of two bell cranks SI and 52, respectively (Figs. 2 and 3), the bell cranks being pivotally mounted on the framework 29. The other arms of said bell cranks are pivotally connected to the insulating bridges 49 and 50, respectively, through links 6| a and 62a.

Disposed on the threaded rods 59, 64 are coil springs 53' and 64, respectively, between the jam nuts 65 and the slotted guideways 66 through which the threaded rods pass. The two threaded rods are biased so that the nuts 6'! and 63 on the ends of the respective rods abut the inner surface of the pivoted lever 58. It will be appreciated that by threading the nuts 61 and 68 on the respective rods 59 and 60, the efiective lengths of the rods may be altered, the jam nuts 65 looking the nuts 67, 68in place on the rod.

Pivoted to the outer end of the short bar 56 is a rocker arm 69 having rollers 70 and H fixed to the ends thereof and cooperating with the point detector rod l7 and its recess 2?. The rollers w, H are biased against the point detector rod by means of spring rods 72 and i3 and coil springs '54 and i5 disposed thereon, respectively. The spring rods are pivoted at their outer ends to the ends of the rocker arm 69 and slidably supported at their inner ends in lugs 76 of the framework 29. The coil springs 74 and '15 are disposed about their respective spring rods between the lugs 16 and offset lugs 71 and 18 fixed to the spring rods l5, l2, respectively. The offset lugs 17, 18 are L-shaped, the free ends 19 and 80, respectively, just engaging the ends of the pivoted lever 53 without pressure due to spring bias.

Referrim now in particular to Fig. 4 of the drawings for an understanding of the operation of my novel point detector mechanism described, the point detector rod I! is illustrated in its extreme normal position indicative of the normal position of the switch points 3 and 4 as illustrated in Fig. 1. The offset lugs H, is, the spring rods l2, l3, and the threaded rods 59 and 60 are so proportioned as to length, and the coil springs 64 and i4, '55 so biased that when and only when the point detector rod 11 is in its extreme normal position, will the roller be within the point detector rod recess 21. The same proportioning of elements and the sam spring bias will also insure the roller H being within the recess 21 when and only when the point detector rod is in its extreme reverse position indicative of a reverse position of the switch points 3 and 4 in which the switch point 3 engages the fixed rail I.

As previously set forth, the cams 43 and 44 cooperate with the contact fingers 49 and 50 by way of the rollers 5| and 52 fixed to the insulating bridges 49 and 50. It will be noted in Fig. 4 that the earns 43 and 44 are fixed to the shaft 28 so that the respective cam notches and 46 are 240 apart. In the description which follows, the cam 44 will be referred to as the normal contact cam, while cam 43 will be referred to as the reverse contact cam. The normal contact cam notch 46 will receive the roller 52 when the switch points 3 and 4 are in their normal position as illustrated in Fig. 1, while the roller 55 will ride on the periphery of the reverse contact cam 43. When the switch A is reversed, the movement of the slide bar 24 through the rack 25, pinion 26 and gear 34 will rotate the shaft 240 so that the roller 5| will then be received within the reverse contact cam notch 45 and roller 52 will ride on the periphery of the normal contact cam 44.

When the switch A is in its normal position and properly locked, the point detector rod notch 21 will receive the roller 10 of the rocker arm 69 which will permit the insulating bridge to assume an inclined position with the roller 52 within the normal contact cam notch 44. Contact fingers 48 will then engage the fixed contacts 54. On the other hand, the roller ll of the rocker arm will engage the point detector rod ll tending to lift the right side of the pivoted bar and the threaded rod 59. The roller 5! of the insulating bridge 49 riding the periphery of the reverse contact cam will lift the contact fingers 4'! to engage the shunting contact 55. The contact fingers 4T, 48 and the fixed contacts 53, 54 and control the indicating circuits; the closed contacts 41, 53 and 48, 54 providing a, clear signal over the switch A, the open contacts 41, 53 and 48, 54 providing a stop signal, and the engagement of the shunting contacts 4?, 55 and 48, 55 short-circuiting the signal control relay and thus preventing stray currents or crosses on the external wires from energizing the relay improperly and causing improper signal operation.

When the switch points 3 and 4 are reversed, the slide bar 24 will, through the rack 25 and pinion 26, rotate the gear 3!] and the shaft 28 to reverse the positions of the normal and reverse contact cams 44 and 43. During movement of the switch points 3 and 4, the point detector rod will be moved from the extreme position illustrated to an extreme reverse position. With the slide bar at the end of its reverse stroke, the switch will be properly locked and the point detector rod ll will have been moved into its extreme position wherein the roller '4! enters the recess 21!. The insulating bridge 49 will thus be inclined so that roller 5! is within the reverse cam notch 45 and the shunting contacts 41, 55 will open and the contacts 41, 53 will close. The normal contact cam 44 having been rotated 240 will lift the contact finger 48 into engagement with the shunting contact 55.

The point detector mechanism described has been termed a selective mechanism in that the proper indicating contacts are closed for a particular position of the switch points 3 and 4. Thus, if the switch is trailed when the switch points; are; in-their norm-al-,position'asaillustnated' in Fig. 1, the. indication contacts 4.8; 54. will; be opened. Should the switch Abe tnailedavh-enthe switchyp ints are linatrheiri reverse :nosition,,;tne indication contacts; 37-, :53 will: be opened. jlfgwe asssumethatthe switch is: in its normalrposition as illustrateddnF-ig, l and' the switch istnailed, the point detector rodwill be moved by'thetrailed switch points to force theroller l; outof-v the point detector rod recess 27. The roller -H;=acting as a fulcrum will allow the rocker arm. 69 to pivot about this point; in a; clockwise direction to move the'sp-ring rod,?.2 and-offset lug I8 upwardly. The, short baritt W111i also be moved upwardly but only. abouthalf the distance that the-spring rod "it-is moved since the shortbar-56 is aboutrmidway between the rollers 10 and H. The bias of the springsi l andqii being-such that theoffset'lug portion-8t just touches the pivoted lever 58, the upward movement'of the spring rod 12 will bypassany effect the pivoted lever may have on the threaded rod -60 and act directly on the threaded rod-6i) to pivot the bell crank =62 in a counterclockwisedirection .(Fig. 3) tomove the link 52a upwardly. The insulatingqbridge 50 will thus be moved upwardly to open the indication contacts 48, 54 to'provide a stop signal over-the switch A.

If theswitch Ais trailed when the switch points 3 and 4 are in their reverse position, the roller II will be forced out ofthepoint detector rod recess 21 to-move the spring rod-1.3- and threaded rod -59. upwardly to openj-thepcontactsfl, 53 -and to close the contacts 4?, 5-5; the contacts 338,55 being closedby the action ofthenormalcam- 4'4 and the roller'52 on the'periphery thereof.

It will be appreciatedirom the foregoing de' scription that the cooperation of the roller'tfl: and the point-detector rod recess -21 will. permit the contacts 48,54 to close when the switch A is. in its normal position, and to open-the contacts1-48,u5'4 and close the shunting contacts=-48f55 whenever the switch is trailed in its normal position. Thus, the closed contacts 4.8, 54 will indicate; that the switch point 4 is against the fixedrrail 2. Similarly, the cooperation of the roller Tl and't-he' point detector rod recessZi willypermitthecontacts 4'5, 53*to close'when the switch A is-locked in its reverse-position and to .openjthecontacts 4'1, 53 and close the :shunting'contacts v41, 55 when the switch A is trailed initsyreverseposition. The closed contacts 4?, T53'.Wi11 indicate that the switch point 3 is against the fixed rail i. The point detector-mechanismdescribedis thus selectivein-that the roller on-theleft side-of the machine (Fig. 4) will: always operate the indication contacts on the left-side of the machine, and thercller (H) on-theright side of the machine will always operate the indication contacts on the right side ofthemachine.

In point detector mechanisms of" previous design it was possible 'to operate the switch and open and close the indication contacts with the point detector rod disconnected or broken off and with the point detector rod remaining in either of its extreme positions with a roller of the rocker arm within the point detector-rod recess. In the pointdetector mechanism hereindescribed, I have overcome this shortcoming of previous mechanisms by increasing-the length of the pivoted lever 58 to the length shown in the drawings and adding the offset lugs T1 and 'l-Sto the respective spring rods.

If-w-e consider the point detector mechanism herein described without the ofiset lugs 11 and 1.8, it .will be ap reciated that the pivotediever, 58, the short-bar 56 and thegrockerarm .69iorm a walking-beam arrangement. If we assume the detector rod as being disconnectedfro-m the front rod I and remaining in its normalv position as illustrated in Fig. 4, a reversal-of the-switch will rotate the contact'cams .43: and 4.4 to their reverse positions in which roller :5l: mayzenter the cam. notch 45 and roller 52 will ride onthe periphery of cam 44 to close-the shunting contacts .48, .55. Since the roller 1-0 remains in the-pointdetector rod=recess 21,.the rocker arm 69 will be tilted'to hold the short bar .56 in the position-illustrated. The :normal contact cam 44 holding the insulating bridge-.50, in its tilted position will lift the threaded rod 60 andthe nut .68 against the bias of the spring 54. The roller 5| being opposite, the reverse contactcamnotch.45wil1'enter the notch-due to the downward pull of the spring.63. The nut 61 will thus engage the lever 58 tending-to r0- tate the lever 58 in a clockwise direction. {The indication contacts .41, 53 will thus be..closed despite the disconnected point detector rod.

Under the same conditions withthe pointdetector mechanism including the extendediever 58 and ofiset lugs Hand 18 as described, a.reversal ,of the switch will rotate the contactmams 43 and-44 to their reversepositions. ,The normal contact .cam 44 willclose theshunting contacts- 48, 53, but the reverse contact ,cam 43 will not affect the-condition of the closed shunting contacts 41,55. The rolleril riding on the surfaceof the point detectorrod I1 will Iiftthe spring rod 13; the offset lug end 19 lifting the end or" the lever .58. and the threaded rod 759. The bridge .49- and contact finger 4'! will be held in their inclined positions as illustrated, with the. shunting contacts. 41, -55v closed. Thus both shunting contacts. 48, 55 and.41,.;55 will be closed.

-A return of the switchpoints to their normal position will .permit the shuntingcontacts 43, 55..to.op.en and the indication contacts-.48,.-54.tp close. Under similar circumstances-shouldthe point detector rod become disconnected when switch A is in its reverse position, the roller .11 WilLIemain. in the rccessZT permitting thecontactsAl, 53 .to close, while roller 10, ridingon the. periphery. of the point. detector rod, willhold the shunting contacts 48, .55 closed atalltiines. Thus inoperating the switch and lock move mentB from aremotepoint, the continued. failur-e-of the signals to clear when the switch is thrown to. acertain position will indicate that theswitchand lock movement is not workin properly. and. a maintainer will then be. sent out to. check the operation of. themovement.

Ihave thus provided a point detector mechanism fora switch and lock movement which will selectively-openthe indication contacts of the circuitcontroller in response to the positions of; the individual switch points of the switch. In accordance with my invention, the nonselective point detector ,mechanisms now in operation may bereadily adaptedto operate as selective point detector mechanisms by ,the additions thereto of a lengthened pivoted lever (58) and the off-setlugs (TI, 18) in the manner described.

Although I have herein shown and described onlyone form or" a selective point detectormechanism embodying my invention, it is understood that-various changes and modifications may be made-therein within the scope of the'appended claims without departing from the spirit and scope :of my invention.

Having thus described my invention, what I claim is:

1. A point detector for switch operating apparatus of the type having a slide bar for locking the switch points in their two extreme positions, a shaft operatively connected with said slide bar for rotation thereby, two cams on said shaft, a first contact actuating member cooperating with the first of said cams adapted to be moved to a first contact actuating position when said switch points are locked in their first position and to a second contact actuating position when said switch points are not in their first position and a second contact actuating member cooperating with the second of said cams adapted to be moved to a first contact actuating position when said switch points are locked in their second position and to a second contact actuating position when said switch points are not in their second position, comprising a point detector rod movable by said switch points to a first position when said switch points are in their first position and to a second position when said switch points are in their second position, a recess in said point detector rod, a rocker arm pivoted inter mediate its ends and carrying a first and second roller adapted to ride on the periphery of said point detector rod, said first roller entering the point detector rod recess when and only when said point detector rod is in its first position, said second roller entering the point detector rod recess when and only when said point detector rod is in its second position; means connected to said rocker arm on one side of its pivot point and cooperating with said first contact actuating member to move and hold only said first contact actuating member in its second contact actuating position whenever said first roller is out of said point detector rod recess, and a second means connected to said rocker arm on the other side of its pivot point and cooperating with said second contact actuating member to move and hold only said second contact actuating member in its second contact actuating position whenever said second roller is out of said point detector rod recess.

2. A point detector for switch operating apparatus of the type having a slide bar for looking the switch points in their two extreme positions, a shaft operatively connected with said slide bar for rotation thereby, two cams on said shaft, a first contact actuating member cooperating with the first of said cams adapted to be moved to a first contact actuating position when said switch points are locked in their first position and to a second contact actuating position when said switch points are not in their first position and a second contact actuating member cooperating with the second of said cams adapted to be moved to a first contact actuating position when said switch points are locked in their second position and to a second contact actuating position when said switch points are not in their second position, comprising a point detector rod movable by said switch points to a first position when said switch points are in their first position and to a second position when said switch points are in their second position, a recess in said point detector rod, a rocker arm pivoted intermediate its ends, a first roller and a second roller carried by the ends of said rocker arm adapted to ride on the periphery of said point detector rod, said first roller entering the point detector rod recess when and only when said point detector rod is in its first position, said second roller entering said point detector rod recess when and only when said point de tector rod is in its second position, an abutment member carried by each end of said rocker arm,

. means cooperating with the abutment member on one side of said rocker arm to move and hold only said first contact actuating member in its second contact actuating position whenever said first roller is out of the point detector rod recess, and a second means cooperating with the abutment member on the other side of said rocker arm to move and hold only said second contact actuating member in its second contact actuating position whenever said second roller is out of said point detector rod recess.

3. A point detector for switch operating apparatus of the type having a slide bar for locking the switch points in their two extreme positions, a shaft operatively connected with said slide bar for rotation thereby, two cams on said shaft, a first contact actuating member cooperating with the first of said cams adapted to be moved to a first contact actuating position when said switch points are locked in their first position and to a second contact actuating position when said switch points are not in their first position and a second contact actuating member cooperating with the second of said cams adapted to be moved to a first contact actuating position when. said switch points are locked in their second position and to a second contact actuating position when said switch points are not in their second position, comprising a point detector rod movable by said switch points to a first position when said switch points are in their first position and to a second position when said switch points are in their second position, a recess in said point detector rod, a rocker arm pivoted intermediate its ends, a first roller and a second roller carried by the ends of said rocker arm adapted to ride on the periphery of said point detector rod, said first roller entering the point detector rod recess when and only when said point detector rod is in its first position, said second roller entering said point detector rod recess when and only when said point detector rod is in its second position, an abutment member carried by each end of said rocker arm, a pivoted lever, the ends of said lever being engaged by said abutment members; and link members connected to said first and second contact actuating members and cooperating with said pivoted lever, sO that when said point detector rod is out of its first position said first roller will pivot said rocker arm to pivot said lever by an abutment member in one direction to move only the link member connected to said first contact actuating member thereby moving said first contact actuating member to its second contact actuating position, and when said point detector rod is out of its second position said second roller will pivot said rocker arm to pivot said lever by the other abutment member in an opposite direction to move only the link member connected to said second contact actuating member thereby moving said contact actuating member to its second contact actuating position.

WILLIAM M. POOLE.

References Cited in the file of this patent UNITED STATES PATENTS

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