US1953461A - Railway switch point detector - Google Patents

Description

April 3, 1934. L B E 1,953,461

RAILWAY SWITCH POINTDETECTOR FiledMaroh 30, 1932 3 Sheets-Sheet 1 Hi5" ATTORNEY.

April 1934- H 1.. BONE 1,953,461

RAILWAY SWITCH POINT DETECTOR Filed March C50, 1932 3 Sheets-Sheet 2 INVENTOR.

Herbert L. Bone HIS A TT ORNE Y.

April 3, 1934. H. BONE 1,953,461

RAILWAY SWITCH POINT DETECTOR Filed March 30, 1932 3 Sheets-Sheet 5 INVENTOR. Ho bo z L.B0120.

HIS A T TOR N E Y.

Patented Apr. 3, 1934 warren srarss PATENT OFFICE RAILWAY SWITCH POINT DETECTOR Application March 30, 1932, Serial No. 602,024

29 Claims.

My invention relates to railway switch point detectors;

One object of my invention is to insure the safety of trains and vehicles moving over railway switches. 1

It is customary in automatic block signal territory and at interlockings to provide at each switch a circuit controller which is operated in part by the mechanism of the switch machine, and lb? in part by a detector rod or rods attached to the switch points, and the function of whichis to so control the signals governing traiiic over the switch that they will indicate stop unless the switch points occupy their proper positions rela- 131. tive to the stock rails and are locked in' these positions. When, by error, a switch is trailed through, the switch points are displaced at the top an amount which would easily operate the circuit controller if the connection of the point 2'0? detector rod or rods with the points could be made at the top of the points. However, for clearance reasons, it is necessary to connect the detector rods to the switch points some distance below the top of the points, where, due to the rolling of the points during the trailing, the amount of the movement may not be more than one-half of that occurring at the top; and, furthermore, aftera train has trailed throughthe switch, the points will usually spring back toward their orig- 301 inal positions a certain amount. As a result, the

final displacement of the point detector rod or rods may be very little, if any, more than the displacement which would correspond to a maximum permissible opening of the closed switch point, (which is the setting at which the circuit controller would be adjusted to operate the indication contacts), while the opening of the closed point at the top might be sufiicient'to be extremely dangerous for subsequent high speed train move ments. In order to insure that this dangerous condition will be detected, I provide an improved latching mechanism for holding the indication contacts in their operated positions after they are once operated until they are released by a maintainer. Thus, even though the switch points spring back toward their proper positions after the train has trailed through the switch, the signals governing trailic over the switch will continue to display a restrictive indication until the maintainer releases the latching mechanism and permits the contacts of the circuit controller to return to their normal positions; It is assumed that before the maintainer does this, he will inspect the switch points and, if damaged, repair them, thus guarding against adangerous condition due to damaged switch points.

I will describe one form of point detectors embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is atop plan view showing a railway switch operated by a switch machine E provided with a point detector embodying my invention. Fig. 2 is a top plan view of the point detector and some of the associated parts of the switch machine E, certain parts being broken away or removed for clearness. Fig. 3 is a vertical sectional view taken substantially on the line III-III of Fig. 2, but drawn to a somewhat smaller scale than Fig. 2. Fig. i is a view of a portion of the latch mechanism forming part of the point detector shown in Figs. 2 and 3, and embodyingmy invention. Fig. 5 is an elevational view of the portion of the latch mechanism shown in Fig. 4. Fig. 6 is a sectional view taken on the line VIVI of Fig. 5. Fig. 7 is a fragmentary sectional view taken on the line VII VII of Fig. 2. Fig. 8 is a fragmentary sectional view taken on the line VIII- VIII of Fig. 3. Fig. 9 is a detail view showing the so cam 16 forming part of my point detector, and one of the contacts'controlled thereby, as they appear when viewed from the left in Fig. 8.

Similar reference characters refer to similar parts in each of the several views;

Referring first to Fig. 1, the referencechar-' aoter M designates a railway switch comprising, as usual, two fixed rails B and B and two movable switch points A and A The fixed rails B and B are laid on tie plates 1 and arese- 9o" cured to the crossties 2 in the usual manner. The switch points'Aand A are connected together for simultaneous movement by a bridle rod 3 and a front rod 4', and the bridle rod 3, in turn, is connected to the operating rod 0 of a switch machine E, whereby the switch may be moved into a normal or areverse position. When the switch occupies its normal position, in which it is illustrated in Fig. 1, the switch point A engages the fixed rail B, and the switch point A 166 is spaced a slight distance from the fixed rail B When the switch is reversed, however, the

switch point A then engages the fixed rail B and the switch point A is spaced from the rail B.

Extending into one end of switch machine E is a lock rod L and a point detector rod P. The" lock-rod L is slidably mounted in suitable guides in the switch machine for horizontal, movements in directions parallel to the operating'rod O and, W W

as here shown,'has its right-hand end 5 formed 0 integral with the front rod 4. The point detec tor rod P is also slidably mounted in suitable guides in the switch machine E for movements in directions parallel to the operating rod 0 and lock rod L, and has one end connected to the switch point A by means of a connecting rod 6 and a bracket '7. It will be noted that, as here shown, the lock rod L and the point detector rod each comprise two bars, suitable means being provided to permit relative longitudinal movements between the bars of each rod for the purpose of adjustment.

While a point detector embodying my invention may be applied to a switch machine of any suitable type, the switch machine E to which I have shown it applied in the drawings is similar in all respects to the switch machine shown and described in an application for Letters Patent of the United States, Serial No. 600,601, filed by William C. McWhirter, on March 23, 1932, for Railway switch operating apparatus. Inasmuch as the construction and operation of the switch machine E is similar to that described in the said McWhirter application, only those parts which are thought to be essential for a clear understanding of my present invention have been shown in detail in the drawings, and will be described here.

Referring now particularly to Figs. 2, 3 and 8, the point detector embodying my invention is here shown as comprising a suitable circuit controller which is located within the casing of the switch machine directly above the lock rod L and point detector rod P, and which is operated in part by a slide bar N. The slide bar N extends longitudinally of the switch machine and is provided on its upper face with two locking dogs 8 and 9. When the switch points occupy their normal positions in which they are shown in Fig.

'1, the slide bar N occupies the extreme position in which it is shown in Figs. 2 and 3, and under these conditions, the locking dog 8 enters a pair of notches 100 in the lock rod L to lock the switch points in their normal positions. When, however, the switch machine is operated to move the switch points to their reverse positions, the slide bar N is moved by the operating mechanism, prior to the movement or" the operating rod 0 which reverses the switch, toward the left, as viewed in Figs. 2 and 3, to an intermediate position in which the dogS is withdrawn from the notches 100 in the lock rod L, thus unlocking the switch; and when the movement of the switch to its full reverse position by the operating rod has been completed, the slide bar N is then moved in the same direction as before, to another extreme position in which the locking dog 9. enters another pair of notches (not shown) in the lock rod L, thus locking the switch in its reverse position. When the switch machine is next operated to restore the switch to its normal position, the subsequent movements of the slide bar and operating rod above described are maintained, but the directions of the movements are reversed.

Formed in the upper face of the locking dog 9 are rack teeth 10 which mesh with an idler gear 12. The idler gear 12, in turn, meshes with a gear 13. which is secured to a cam shaft 14. As shown in Fig. 2, the cam shaft 14 is journalled at its ends in suitable bearings formed in a supporting casting 15, and has fixed thereto two spaced cams 16 and 16 which are concentric therewith. The cam 16 is provided in its periphery with a notch 17 (see Figs. 3 and 8), and is adapted when rotated, to actuate a pair of contact fingers 18 which are connected together for simultaneous movement by an insulating bridge 19 The cam 16 is likewise provided in its periphery with a notch 17 as shown in Fig. 9, and is adapted when rotated to actuate a pair of contact fingers 18 which are connected together for simultaneous movement by an insulating bridge 19 The two pairs of contact fingers 18 and 18 are provided with rollers 20 and 20*, respectively, which cooperate with the corresponding cams 16 and 16 and serve as an actuating medium for the contact fingers when the associated cams are rotated. When the rollers 20 or 20 is in alignment with the notch 17 or 17 in the associated cam, the fingers 18 or 18 move to an inclined position in which the associated roller enters the aligned notch, except under certain conditions which will be described hereinafter, and when in this inclined position, these fingers engage lower fixed contact fingers 21 21 or 21 21 When, how ever, the rollers are riding on the peripheries of the associated cams, the contact fingers 18 or 18 are lifted to cause the inner finger or" each pair to engage an upper stationary contact member 22. As here shown, the parts are so arranged and so proportioned that the notch 17 in the cam 16 will align with the roller 20 when and only when the slide bar N occupies the extreme position in which it looks the switch in its normal position as shown in the drawings, and that the notch 1'? in the cam 16 will align with the roller 20 when and only when the slide bar N occupies the extreme position in which it looks the switch in its reverse position.

The contact fingers 18 and 18 are further controlled in accordance with the positions of the switch points'by suitable means which I will now describe. As here shown, these means comprise two crossbars 23 and 23 slidably mounted in the framework 15 directly below the cam shaft 14, and extending at right angles to the point detector rod P in parallel spaced relation. The crossbar 23 is provided with a roller 24 and is biased by means of a spring 25 in such direction that the roller 24 constantly engages the lefthand edges, as viewed in Fig. 2, of the detector bars of the point detector rod P. The crossbar 23 is likewise provided with a roller 24 and is biased by means of a spring 25 in such direction that the roller 24 constantly engages the righthand edges, as viewed in Fig. 2, of the detector bars of the point detector rod P. Formed in the left and right-hand edges, respectively, of the detector bars of the point detector P, and cooperating with the rollers 24 and 24 are normal and reverse notches 26 and 26. These notches are so proportioned and the bars of the detector rod are so adjusted that the normal notches 2G will receive the roller 2 1 when and only when the switch occupies its normal position and the switch point A is closed in the proper manner, and that the reverse notches 26* will receive the roller 24* when and only when the switch occupies its reverse position and the switch point A is properly closed.

The crossbar 23 operates a cam member 27, and the crossbar 23 operates a cam member 2'7 (see Figs. 3 and 8). The cam member 2''! is journalled on the cam shaft 14 adjacent the cam 16 and is provided with a downwardly extending gear segment 28* which meshes with rack teeth 29 formed on the upper side of the crossbar 23 in such manner that this cam member will be rotated whenever crossbar 23 moves. The cam member 27 is also provided with an upwardly extending cam segment 30 which cooperates with the roller 20 carried by the contact fingers 18 The cam member 27 is similarly journalled on the cam shaft 14: adjacent the cam 16 and is provided with a downwardly extending gear segment 28 which meshes with rack teeth 29 formed on the upper side of the crossbar 23 and with an upwardly extending cam segment i which cooperates with the roller 20 carried by the contact fingers 18 The upper portions of the cam segments, as here shown, are curved and are provided with notches 31 and 31 respectively. The parts are so proportioned that the notch 31 will align with the roller 20 when and only when the roller 24 on the crossbar 23 is within the normal notches 26 in the detector rod P, and that the notch 31* will align with the roller 20' when and only when the roller 24* on the crossbar 23 is within the reverse notches in the detector rod P. It will be seen, therefore, from the foregoing that when the switch occupies its normal position in which it is shown in Fig. l, and is locked in this position by the slide bar N, the notch 31 in the cam segment 30 and the notch 1'7 in the cam w will both align with roller 20 carried by the contact fingers 18 and under these conditions, the contact fingers 18 will assume their inclined positions in which the contacts 18 21 are closed. and the contact l8* 22 is open. Likewise, when the switch occupies its reverse position, and is locked in this position by the slide bar N, the notch 31 the cam segment 30* and the notch if? in the cam 16* will both align with the roller 20* carried by the contact fingers 18 and under these conditions, the contact fingers 18 will assume their inclined positions in which the contacts 18 -21 are closed, and the contact Ri -22 is open. When, however, the switch is being moved from one extreme position to the other extreme position, the notch 31 in the cam segment 30 and the notch l7 in the cam 16* will both be out of alignment with the roller and the notch 31 in the cam segment and the notch 17 in the cam l6 will both be out of alignment with the roller 20 and under these conditions, both sets of contact fingers 18 and 18 will be held in their raised positions, so that the contacts Mi -22 and 18 22 will be closed while the contacts l8 -2l and Ri -21 will all be open.

It will be noted that the crossbars 23 and 23 are each provided with a second roller 32 or 32 These rollers are adapted to cooperate with a second point detector rod, not shown, which would be provided in installations where the switch machine A is utilized to operate a double slip switch or a movable point frog. In either instance, both pairs of switch points would have to occupy their proper positions relative to the fixed rails, and the closed points would have to be properly adjusted before either pair of contact fingers would move to their inclined positions. A second rod might also be utilized in connection with a single slip switch in the event that it is desired to control the circuit controller by both switch points instead of by only one switch point, as shown in the drawings. Under these conditions both switch points would have to occupy their proper positions relative to the stock rails before either pair of fingers would move to their inclined positions, as will be readily understood.

As best seen in Fig. 2, a latching finger 34: is pivotally attached intermediate its ends to one end of the crossbar 23 by means of a pin 35,

and is provided at one end with a latch surface 36 and at the other end with an axially extending slot 37*. The slot 3'7 receives a bolt 38 (see Fig. 7) which is secured to a lug 39 formed on the framework 15, and it will be apparent, therefore, that any movement of the crossbar 23 will rotate the latching finger 3% about the bolt 38 as a fulcrum. It will also be apparent, that since, as here shown, the crossbar 23 is connected with the latching finger 34? near the middle of the finger, the distance through which the latch surface 36 is moved for a given movement of the crossbar will be nearly twice the distance through which the crossbar is moved. The latch surface 36 is adapted to cooperate with a vertically movable latch button e0 in a manner which will be described hereinafter, and the bolt 38 is made eccentric so that, for any given position of the crossbar, the horizontal position of the latch surface relative to the left-hand side of the latch button, as viewed in Fig. 2, may be adjusted by turning this bolt. In order to facilitate the turning of the bolt, the upper. end of the bolt is provided with a saw kerf d2 into which a screw driver or other suitable tool may be inserted. Vertical displacement of the latching finger at the end which is provided with the latch surface is prevented by an overlying lug 41 formed on the supporting casting 15. The parts'are so proportioned that when the crossbar 23 occupies the position in which the roller 2 h enters the normal notches 26 in the point detector rod P, as shown in Fig. 2, the latching finger 34* will occupy the position in which the latch surface 36 is superposed over the latch button 40, but that, when the crossbar 23 occupies the position in which the roller 24. is forced out of the normal notches 26 in the point detector rod P, the latching finger 3% will be moved toward the left, as viewed in Fig. 2, to the position in which the latch button 40, if raised, would just clear the latch surface 36*. A latching finger 34*, similar to the latching finger 34 is pivotally attached intermediate its ends to one end of the crossbar 23 in the same manner as the latching finger 34 is attached to the crossbar 23 and is provided at one end with a latch surface 36 which cooperates with the latch button in such manner that the latch surface 36* will be superposed over the latch button if) when the roller 24 1';

on the crossbar 23 is within the reverse notches 26 in the point detector rod P, but that, when the roller 241 in the crossbar 23 is forced out of the reverse notches 26 in the point detector rod P, the latch surface 26 will then occupy the position in which it is illustrated in the drawings, so that the latch button 40, if raised, would clear this surface.

The latch button 40 forms part of a latching device, designated as a whole by the reference character C, and shown in detail in Figs. 4, 5, and 6. Referring now to Figs. 4, 5, and 6, the latching device C comprises a substantially horizontal latch arm 44: which is pivotally mounted at one end on a horizontal pin 45 carried by the spaced vertical sides 46 of a suitable supporting bracket 46. The arm 44 extends between vertical guides 47 formed on the upper edges of the sides 46 of the bracket 46, and is provided at its free end with a threaded hole 48 into which the latch button 10 is adjustably screwed. The latch button 40 is maintained in an adjusted position by means of a suitable jam nut 49. Operatively connected with the latch arm 44 at the portion which is located between the guides 47 is a spring roller on the bracket 46.

tappet 56 comprising a plunger 50 a spring 50 and a roller 56 (see Fig. 6). The plunger 50 extends freely through a hole 51 in the arm 44, and is provided at its upper end with a nut 43, and at its lower end with a bifurcated head 50 between the bifurcations of which the roller 50 is pivoted on a pin 50 They spring 50 surrounds the plunger 50 between the head 50 and the underside of the arm 44, and is provided with suf- 'ficientcompression so that, if the roller 50 is raised vertically, a corresponding vertical motion of the latch arm will take place provided the resistance to the raising of the arm is not more than that which would reasonably be expected due to friction in the bearings and the weight of the arm. It follows, therefore, that if the resistance to the raising of the arm is greater than that resulting from friction in the bearings and the weight of the arm, due for example, to the latch button engaging the underside of one or the other of the latching fingers 34 or 34* as will sometimes be the case under certain conditions which will be described hereinafter, the spring 50 will become compressed, and the latch arm will not be raised. The roller 50 is guided by a transverse slot 53 formed in the lower end of the bracket 45, which slot also serves to limit the amount of upward movement of the roller. The lowermost position to which the arm 44 can drop is limited by two shoulders 52 formed on the sides 46 of the bracket 46 adjacent the guides 47, as best seen in Figs. 5 and 6.

The latching device further comprises suitable means for automatically maintaining the latch arm in its uppermost position after it has once been moved to this position, until it is manually restored to its lowermost or normal position. As. here shown, this means comprises a latch catch 54 pivoted on a pin 55 carried by a lug 56 formed The latch catch 54 is provided with a vertical arm 54 and with a horizontal 54*. When the latch arm 44 occupies its lowermost position in which it is shown in Figs. 5 and 6, the arm 54 of the latch catch54 extends into a notch 57 formed in the side of the latch arm 44. When, however, the latch arm 44 is moved to its uppermost position, the arm 54 of the latch catch 54 becomes disengaged from the notch 57, and due to the bias of a handle 54 formed on the arm 54' the latch catch 54 then moves to a position in which a heel 54 on the arm engages a stop 54 formed on the bracket. 46. When in this latter position, the upper end of the vertical arm 54 engages the underside of the latch arm 44 and prevents the latch arm 44 from returning to its lowermost position. 'Tnus it will be seen that once the latch arm 44 is raised, it will not be possible for it to return to its lowermost position until the latch catch is manually returned to the position in which the vertical arm 54* aligns with the notch 57 in the'latch arm 44.

The bracket 46 is attached to thesupporting casting 15 in such a position that the roller 50 of the spring roller tappet 50 will enter a recess 58 (see Figs. 2 and 3) formed in the upper side of the siide bar N when and only when the slide bar N occupies its intermediate position. 'The parts are so proportioned that when the roller 50 is within the recess 58 in the slide bar N, the latch arm 44 will be permitted to move to its lowermost position under the influence of gravity, but that, when the roller is out of the recess 58, as is the case when the slide bar occupies either of its two extreme positions, the arm 44 will then tend to move to its uppermcstposition under the action of the spring roller tappet 50. The parts are further so proportioned that if either of the latching fingers 34 occupy the position in which the associated latch surface 36 is superposed over the button 40 when the arm 44 is urged upwardly by the spring roller tappet 50, the latch button 40 will engage the underside of the superposed arm and prevent the arm from rising.

The operation of the apparatus as a whole is as follows: As shown in the drawings, the switch occupies its normal position and is locked in this position by the slide bar N. The cam member 2'7 therefore occupies the position in which the notch 31 in the cam segment 30 is in alignment with the roller 20 on the contact finger 18 and the cam 16 occupies the position in which the notch 17 is also in alignment with the roller 20*; while the cam member 27 occupies the position in which the notch 31 in the cam segment 30 is out of alignment with the roller 20* in the contact fingers 18 and the cam 16 occupies the position in which the notch 17 is out of alignment with the roller 20'. The contact fingers 18, therefore, occupy their inclined positions in which the contacts Hi -21 are closed and the contact 1s -22 is open, and the contact fingers 18 oocupy their raised positions in which the contacts 18 21 are open and the contact 18 22 is closed. Since the slide bar N occupies its normal extreme position, roller 55 of the spring roller tappet 50 is out of the recess 58 in the slide bar, and the spring roller tappet 50 accordingly tends to raise the latch arm 44. The latch arm 44 is prevented from moving to its uppermost position under these conditions, however, because the latching finger 34 occupies the position in which the latch surface 36 is superposed above the latch button 45, as clearly shown in Fig. 2.

T will now assume that with the parts inthe position just described, the switch machine E is operated in a manner to move the switch from its normal to its reverse position. As previously pointed out, when the switch machine is operated to reverse the switch, the slide bar N is moved from the extreme position shown to an intermediate position prior to the movement of the operating rod which reverses the switch points, and to another extreme position upon the completion of the movement of the switch points to their reverse positions. During the movement of the slide bar N to its intermediate position, the cam 16 is rotated through the medium of the gears 12 and 13 to a position in which the notch 1'7 is out of alignment with the roller 2-5) on the contact fingers 18 and these contact fingers are, therefore, moved to their raised positions in which contacts HE -21 are open and contact le -22 is closed. Furthermore, during the movement of the slide bar N to its intermediate position, the roller 56 of the spring roller tappet 50 of the latching device C moves into the recess 58 in the slide bar N, thus releasing the compression in the spring 50*, and hence permitting the latch arm 44 to remain in its lowermost position under the influence of gravity. As soon as the switch points start to move, the point detector rod P is of course moved, and this movement forces the roller 24 on the crossbar 23 out or" the normal notches 26 in the point detector rod. As a result, cam member 2'7 is rotated to the position in which the notch 31 in the cam segment 30 is out oi alignment with the roller 20 carried by the contact fingers 18?, so that if cam 16% had failed to move these fingers to their raised positions during the movement ofv the slide bar N to its intermediate position for any reason, they would now be moved to their raised positions by the cam member 27 The movement of the crossbar 23 due to the roller 24 being forced out of the normal notches 26 also moves the latching finger 34 in a counter-clockwise direction as viewed in Fig. 2 from the position in which the latch surface 36 overlies the latch button 40 to the position in which the latch surface is located at one side of the latch button in the vertical plane. At this point in the operation of the movement, both latching fingers 34 and 34 are clear of the latch button but, as described above, the roller 50 of the spring roller tappet 50 is now within the notch 58 in the slide bar N, so that the latch arm remains in its lowermost position. When the switch points have reached their full reverse positions, point detector rod P occupies the position in which the reverse notches 26* are in alignment with the roller 20 on the crossbar 23 and the roller 24 therefore, moves into the reverse notches 26*, thus moving the latching finger 34 to the position in which the latching surface 36 is above the latch button 40, and also rotating the cam member 27' to the position in which the notch 31 in the cam segment 36' is in alignment with the roller 20 on the contact fingers 18 The fingers 18 are held in their raised positions by the cam 16*, however, until the slide bar N completes its movement toward the left,

as viewed in Figs. 2 and 3, to lock. the switch points in their reverse positions, at which time the cam 16* is rotated to the position in which the notch 17* is also in alignment with the roller 18*. When the notches 31 and 18 are both in alignment with the roller 20, the contact fingers 18 move to their inclined positions, thus closing contacts Ri --21 and opening contact 18 -22. The final movement of the slide bar N toward the left also causes roller 50 of the spring roller tappet 50 of the latching device C to move out of the recess 58 in the slide bar N, thus urging this latch arm to rise. This latch arm is now prevented from rising, however, by the latch button 40 engaging the a underside of the latching finger 34 If, when the switch occupies its reverse position, the switch machine E is operated to restore the switch to its normal position, the subsequent movements of the parts just described is maintained, but the direction of the movements is reversed. It is thought that the operation of the apparatus, under these conditions, will be readily understood from the foregoing and from an 1nspection of the drawings without describing it in detail.

I will next assume that with the parts in the positions in which they are shown in the drawings, a train trails through the switch. Under these conditions, each time a wheel passes through the switch, the closed point A will be forced away from the associated fixed .rail B, thus moving the point detector rod P toward the right as viewed in Fig. l and upwardly as viewed in Fig. 2. This movement of the point detector rod will normally force the roller 24* on the crossbar 23 out of the normal notches 26 in the point detector rod so that the crossbar 23 will be moved toward the left as viewed in Figs. 2 and 3. This movement of the crossbar 23 in turn, will rotate the cam member 27 to a position in which the roller 29 on the fin ers 18 is forced out of the notch 31 in the cam segment thereby causing contacts 18 21 to become open, and contact hi -22 to be come closed. The movement of the crossbar 23"" will also rotate latching finger 34 to a position in which the latch surface 36 is clear of the latch button 40, the parts being so adjusted that the latch surface will reach the position in which it first clears the latch button 40 at the point in the movement of the crossbar where the contacts 18' --2l first open or shortly thereafter, as desired. As soon as the latch surface 36* clears the latch button, the spring of the spring roller tappet 50 will force the latch arm as upwardly to its uppermost position and, under these conditions, the head of the latch button will lie in the same vertical plane as the latch arm 34 After the latch arm has been moved to its uppermost position, it will subsequently be held in this position by the latch catch 54 in the manner previously described. As a result, if, after the train has trailed completely through the" switch, the switch points tend to spring back toward their normal positions so as to restore the point detector rod to the position in which the normal notches 26 again align with the roller 24*, latch surface 36 will engage the edge of the head of the latch button 40 and prevent the crossbar from moving to the position in which the roller 24 enters the normal notches. It follows, therefore, that under these conditions, the indication contacts 18 -21 will remain open and the contact 18 -22 will remain closed until the latch arm 44 is subsequently restored to its lowermost position. In order to do this, it is necessary for an authorized person to manually restore the latch catch 54 to the position in which it is shown in Fig. 5, and at the same time push downwardly on the latch arm 44. When the latch arm has been fully depressed, the latch button 40 will be moved out of engagement with the latch surface 36* of the latching finger 34 and if the points are then safe for traffic to move over the switch, the spring 25 will 1 15 restore the crossbar 23 to the position in which the roller 24 enters the normal notches 26 in the point detector rod P, thus returning the latching finger 34 to the position in which the latch surface 36 overlies the latch 1'2'0 button 40. The movement of the crossbar 23" to the position in which the roller 24 enters the normal notches 26 will also rotate the cam member 27 to the position in which the notch 31 in the cam segment 30 aligns with the roller 20 on the fingers 18 thus permitting these fingers to move to their inclined positions in which contacts Ili -21 are closed, and the contact 81 -22 is open. It is assumed that the authorized person who manually operates the latch catch will inspect the switch points, and, if damaged, repair them before restoring the latch arm to its lowermost position.

If, after the switch has been trailed in its normal position in the manner just described, the switch is moved to its reverse position by the switch machine while the latch arm 44 is still in its uppermost position, the contact fingers 18 will be held in their raised positions due to the movement of the point detector rod P caused by 140 the reversal of the switch points, and the contact fingers 18 will also be held in their raised positions, because, even though the reverse notches :26 in the point detector rod then align with the roller 24 on the crossbar 23 the latch but- 145 ton 40 will engage the latching surface 36 of the latching'finger 34 and prevent the spring 25 from moving the crossbar 23 to the position in which the roller 24* enters the reverse notches.

In the foregoing, it has been assumed that 150 while the switch was being trailed in its normal position, the points would be moved far enough to force the roller 24 on the crossbar Z3 completely out of the normal notches 26 in the point detector rod P. However, under certain conditions, the motion of the switch points will not be sufficient to do this, and when this is the case, an additional action occurs involving a sloping surface 40 formed on the upper portion of the edge of the latch button 40. To illustrate this action, I will assume that the points are displaced from their normal positions by the trailing movement an amount which moves the point detector rod P just far enough to cause the contact fingers 18 to be raised to the positions to which they are out of engagement with the contact fingers 21 but which is not sufiicient to force the'roller 2? completely out of the normal notches 26 Under these conditions, the movement of the crossbar 23 which takes place will move latching finger 34 far enough so that the latch surface 365 is just clear of the upper edge of the sloping surface 40 of the latch button 40, and as soon as this happens, the spring 50 will start to force the latch arm 44 upwardly. When the latch arm is forced upwardly, the sloping surface of the latch button acts as a wedge and causes further movement of the latching finger and crossbar; this further movement of the crossbar, in turn, causing the contact fingers 18 to move upwardly a. sufiicient amount to provide some margin for wear and inaccuracies in adjustment.

The operation of the apparatus after a train trails through the switch when the switch occupies its reverse position is similar to that which takes place when a train trails through the switch in its normal position, and will be readily understood from an inspection of the drawings without describing it in detail.

It should be pointed out that, while for purposes of description, I have assumed that any abnormal displacement of the switch points from their extreme positionswill be caused by a train trailing the switch, the points might also be displaced in some other manner, such for example, as by dragging equipment, and when this is the case, the apparatus will operate in the same manner as it does when the displacement is due to the switch being trailed.

Although I have herein shown and described only one form of point detectors 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. In a point detector for switch mechanisms having a slide bar for locking the switch points in their extreme positions, a manually operable latch catch, a latching member controlled by said slide bar and said latch catch, a point detector rod adapted to be connected with the switch points to move therewith, a second member controlled jointly by said latching member and said point detector rod, and a contact controlled by said second member.

2. In a point detector for switch mechanisms having a slide bar for locking the switch points in their extreme positions, a point detector rod adapted to be connected with the switch points to move therewith, a crossbar controlled jointly by said slide bar and said detector rod, and a contact controlled jointly by said slide bar and said crossbar.

3. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, and means controlled by said slide bar for preventing said crossbar from returning to said first position if the switch points are moved to said one extreme position after the switch has been trailed by a train while the switch points are in the other extreme position.

4. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, and means controlled by said slide bar for preventing said crossbar from moving to said first position after the switch has been trailed by a train.

5. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, a manually operable member and means controlled by said slide bar and by said manually operable member for preventing said crossbar from moving to said first position after the switch points have been moved away from said one position by a train trailing the switch.

6. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, means controlled by said slide bar for preventing said crossbar from moving to said f rst position after the switch has been trailed by a train until a manually operable member is operated, and a contact controlled by said crossban 7. In combination with a railway switch and a slide bar for locking the switch points in their extreme positions, a point detector rod connected with the switch points to move therewith and provided with a notch, a crossbar provided with a roller which aligns with said notch when and only when the switch points occupy one extreme position, means for biasing said bar in such direction that said roller will normally enter said notch when said roller is in alignment with said notch, means controlled by said slide oar for preventing said crossbar from moving to the position in which said roller enters said notch after a train trails through the switch, and a contact controlled by said crossbar.

8. In combination with a railway switch and a slide bar for locking the switch points in their extreme positions, a point detector rod connected. with the switch points to move therewith, a contact, means controlled by said point detector rod .for operating said contact when the switch points are moved away from one extreme position, and means controlled by said slide bar for retaining .said contact in its operated position until manua1- 1y released if and only if the movement of said extreme positions, a member provided with a roller, a point detector rod connected with the switch points to move therewith and provided .with .a notch which is adapted to receive said roller when and only when the switch points occupy one extreme position, means for biasing said member in such direction that said roller will normally enter said notch when the roller and notchare in alignment, means controlled by :said slide .bar for latching said member in the position in which said roller is out of said notch if the roller is forced out of the notch due to a train trailing the switch when the switch points occupy said one extreme position, and a contact controlled by said member.

10. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions and provided with a recess, a' -contact, means for operating said contact when the switch points are moved away from one extreme position, and means cooperating with said recess for'latching said contact in its operated position if and only if the switch pointsare forced away from said one extreme position when locked in such position by said slide bar.

'11. In combination, a railway switch, a slide 'bar for locking the switch points in their extreme positions and provided with a recess, a contact, a point detector rod connected with the switch points to move therewith, means controlled by said point detector rod for operating said contact when th switch points are moved away from one extreme position, and means cooperating with said recess for latching said contact in its operated position until manually released if and only if the switch points are forced away from said one extreme position when locked in such position by said slide bar.

12. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions and provided with a recess, a point detector rod connected with the switch points to move therewith, a member, means for moving said member from one extreme position to another extreme position when the switch points are moved away from one extreme position, a contact which is operated when said member is moved to its other extreme position, and latching means controlled by said recess and effective for maintaining said member in its other extreme position until manually released if and only if said member is moved to its other extrerne position while the switch points are locked in the one extreme position.

13. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions and provided with a recess, a point detector rod connected with the switch points to move therewith, a member, means for moving said member from one extreme position to another extreme position when the switch points are moved away from one of their extreme positions, a contact which is operated when said member is moved to .its other extreme position, a roller adapted to enter said recess in said slide bar when and only when said switch points are unlocked, and means controlled by said roller for latching said member in its other extremeposition untilmanually released if said member is moved to its other extreme position whil'esaid roller is out of said recess.

14. In a point detector for switch operating mechanisms having a slide bar for locking the switch points 'in their extreme positions, a first crossbar provided with a roller and biased to one position, a second crossbar provided with a roller and biased to one position, a detector bar adapted to be connected with the switch points and provided with a normal notch which receives the roller on said first crossbar when and only when said detector bar occupies a position corresponding vto the normal position of the switch points and with a reverse notch which receives the roller on said second crossbar when and only when said detector bar occupies a position corresponding to the reverse position of the switch points, means controlled by said slide bar for maintaining either crossbar in the position in which the roller carried thereby is out of the cooperating notch in the detector bar if the roller on such crossbar is forced out of the associated notch when the slide bar is in a locking position, and two contacts one controlled by each crossbar.

15. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions and provided with a recess, a latch arm, a latch button secured to said latch arm, a roller adapted to enter said recess when and only when the slide bar occupies a position in which the switch points are unlocked, yieldable means controlled by said roller and effective when and only when said roller is out of said recess for at times moving said latch arm from a first position to a 1 second position, a latch catch for maintaining said latch arm in its second position after it has been moved to its second position, a point detector rod connected with the switch points to move therewith, a member biased to one position, means controlled by said detector rod for moving said member to another position in opposition to its bias when the switch points are moved away from one of their extreme positions, a latching finger pivotally mounted at one end and pivotally attached intermediate its ends to said member and cooperating at its free end with said latch button in such manner that said finger will overlie said latch button and prevent said latch arm from moving to its second position when said member occupies the position to which it is biased but not when said member is moved to its other position and that when said latch arm is moved to its second position said latching finger will engage said latch button and prevent said member from returning to the position to which it is biased.

16. In combination, a railway switch, means for locking the switch in its extreme positions, a. latch button controlled by said locking means and biased to a first position or a second position acposition, means effective when a train trails the switch for moving said latching finger to a second position in which said latch button is free to move to its first position, the parts being so proportioned that when said latch button occupies its first position it will prevent said latching finger from returning to its first position under the action of its bias, and a contact controlled in accordance with the position of said latching finger.

17. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when th switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, and means controlled by said slide bar for preventing said crossbar from returning to said first position after it is moved away from said first position if and only if the movement of said crossbar is due to the switch points being moved away from said one extreme position while they are locked in said one extreme position.

13. In combination with a railway switch and a slide bar for locking the switch points in one exwith the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, means controlled by said slide bar for preventing said crossbar from returning to said first position after it is moved away from said first position if and only if the movement of said crossbar is due to the switch po'nts being moved away from said one extreme position while they are locked in said one extreme position, and a contact controlled by said cross- 45 bar.

19. In combination with a railway switch and a slide bar for locking the switch points in one extreme position, a point detector rod connected with the switch points to move therewith, a crossbar operated by said detector rod in such manner that said crossbar will normally move to a first position when the switch points occupy said one extreme position and to a second position when the switch points are moved away from said one extreme position, means controlled by said slide bar for preventing said crossbar from returning to said first position after it is moved away from said first position if and only if the movement of said crossbar is due to the switch points being moved away from said one extreme position while they are locked said one extreme position, and

a contact controlled jointly by said crossbar and said slide bar.

20. In combination with a railway switch and a slide bar for lock ng the switch points in their extreme positions, a point detector rod connected with the switch points to move therewith, a contact, means controlled by said point detector rod for operating said contact when the switch points are moved away from one extreme position, and means controlled by said slide bar for retaining said contact in its operated position until manually released if and only if the movement of said points away from said one position takes place treme position, a point detector rod connected when the points are locked in said one extreme position.

21. In combination, a railway switch, a slide bar for locking the switch points in their two extreme positions, a detector rod connected with the switch points, two contacts, means controlled by said detector rod for operating the one contact when the switch points are moved away from their one extreme position and for operating the other contact when the switch points are moved away from their other extreme position, a manually operable member, and means controlled by said slide bar for latching both contacts in their operated positions until said manually operable member is subsequently operated if the switch points become displaced while they are locked in either of their extreme positions.

22. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions, a detector rod connected with the switch points to move therewith and provided with two notches, a first crossbar provided with a roller and biased to such position that said roller will enter the one notch in said detector rod when and only when the switch points occupy one extreme position, a second crossbar provided with a roller and biased to such position that said roller will enter the other notch in said detector rod when and only when the switch points occupy the other extreme position, two contacts one controlled by each crossbar and each arranged to be operated when the roller on the associated crossbar is moved out of the cooperating notch insaid detector rod, and means controlled by said slide bar for preventing both crossbars from moving to the position in which the roller carried thereby enters the cooperating notch in said point detector rod if the roller on either crossbar is forced out of the cooperating notch in the detector rod while the switch points are locked.

23. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions, a detector rod connected with the switch points to move therewith and provided with two notches, a first crossbar provided with a roller and biased to such position that said roller will enter the one notch in said detector rod when and only when the switch points occupy one extreme position, a second crossbar provided with a roller and biased to such position that said roller will enter the other notch in said point detector rod when and only when the switch points occupy the other extreme position, two contacts one controlled by each crossbar and each arranged to be operated when the roller on the associated crossbar is moved out of the cooperating notch in said detector rod, a manually controlled member, and means controlled by said slide bar for preventing both crossbars from moving to the position in which the roller carried thereby enters the cooperating notch in said detector rod until after said manually controlled member is operated in the event that the roller on either crossbar is forced out of the cooperating notch in said detector rod while the switch points are locked.

24. In combination, a railway switch, a slide bar for locking the switch points in their two extreme positions, a detector rod connected with the switch points to move therewith and provided with two notches, a first crossbar provided with a roller and biased to such position that said roller will enter the one notch in said detector rod when and only when the switch points occupy one extreme position, a second crossbar provided with a roller and biased to such position that said roller will enter the other notch in said point detector rod when and only when the switch points occupy the other extreme position, two contacts one controlled by each crossbar and each arranged to be operated when the roller on the associated crossbar is forced'out of the cooperating notch in said detector rod, a latch button provided on its upper edge with a sloping surface and normally biased to one position, means including a spring and effective when and only when said switch points are locked by said slide bar for biasing said latch button toward another extreme position, a first latching finger fulcrumed at one end for rotation about a fixed pivot in the plane which said latch button occupics when it is moved to its other extreme position and pivotally attached intermediate its ends to said first crossbar and provided at its other end with a latch surface which cooperates with said latch button, a second latching finger fulcrumed at one end for rotation about a fixed pivot in the plane in which said latch button oc cupies when it is moved to its other extreme position and pivotally attached intermediate its ends to said second crossbar and provided at its other end with a latch surface which cooperates with said latch button, the parts being so proportioned that when the roller on either crossbar is within the cooperating notch in said point detector rod the free end of the associated latching finger will overlie said latch button and prevent it from moving to its second position but that when the roller on either crossbar is forced partway out of the cooperating notch in said point detector rod the associated latching finger will move to the position in which the latch surface of the finger is just clear of the inner edge of the sloping surface of said latch button, whereby if the switch points are then looked the spring associated with said latch button will force said latch button to its other extreme position thus moving said latching finger, due to the sloping surface of said latch button, to the position in which the roller on the associated crossbar is completely out of the cooperating notch in said detector rod.

25. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions, a detector rod connected with the switch points to move therewith and provided with a notch, a member provided with a roller and biased to such position that said roller will enter said notch when and only when the switch points occupy one extreme position, a contact controlled by said member and arranged to be operated when said roller is moved out of said notch, and means controlled by said slide 26. In combination, a railway switch, a slide bar for locking the switch points in their extreme positions, a detector rod connected with the switch points to move therewith and provided with a notch, a member provided with a roller and biased to such position that said roller will enter said notch when and only when the switch points occupy one extreme position, a contact controlled by said member and arranged to be operated when said roller is moved out of said notch, and means controlled by said slide bar and ef fective if said roller is forced partway out of said notch when the switch points are locked in said one extreme position for moving said member to the position in which the roller is all of the Way out of said notch, and for subsequently maintaining said member in this latter position until said member is manually released.

27. In combination with a railway switch and a member for locking the switch in one of its extreme positions, a contact, means for operating said contact when said switch is moved away from said one extreme position, and means efiective if said switch is moved away from said one extreme position when it is locked in such extreme position by said member for retaining said contact in its operated position until said contact is manually released.

28. In combination with a railway switch and a member for locking the switch in one of its extreme positions, a contact, means for operating said contact when said switch is moved away from said one extreme position, and latching mechanism effective if said switch is moved away from said one extreme position when it is locked in such extreme position by said member for retaining said contact in its operated position until said contact is manually released.

29. In combination with a railway switch and a member for locking the switch points in one extreme position, a point detector rod connected with one of said switch points, a contact, means controlled by said detector rod for operating said contact when the switch points are moved away from said one extreme position, and means controlled by said member for retaining said contact in its operated position until said contact is manually released if and only if the movement of said points away from said one extreme position takes place when the points are locked in said one extreme position.

HERBERT L. BONE.

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