US2641691A - Railway switch operating apparatus - Google Patents

Description

June 9, 1953 H. L. BONE 2,641,691

RAILWAY SWITCH OPERATING APPARATUS Filed Jan. 1'7, 1950 v 5 Sheets-Sheet 1 L 2/ 14b INVENTOR.

Fly .5: lgy Hep rt 12.50124? 111s ATTORNEY June 9, 1953 H. L. BONE 2,641,691

RAILWAY SWITCH OPERATING APPARATUS Filed Jan. 17, 1950 5 Sheets-Sheet 2 Insulation Fig 4.

} INVENTOR. Herbert L. Bone BY g HI 5' A TTOHNE) June 9, 1953 H. BONE RAILWAY SWITCH OPERATING APPARATUS 5 Sheets-Sheet 3 Filed Jan. 17, 1950 III'II l l l I l ||||.l I IIIIII ll L. Bone 1115' ATTORNEY June 9, 1953 H. L. BONE 2,641,691

RAILWAY SWITCH OPERATING APPARATUS Filed Jan. 17, 1950 5 Sheets-Sheet 4 IN V EN TOR.

Hen t L. B0120 BY HIS ATTORNEY June 9 1953 H. L. BONE RAILWAY SWITCH OPERATING APPARATUS 5 Sheets-Sheet 5 Filed Jan. 17, 1950 aab aa wwwa 2 g y 6 5 MM 0 8 1 MM 5 5 2 W L w w 8 M F $7 W 0 0; w I? a INVENTOR;

111s ATTORAZ'Y Patented June 9, T953 RAILWAY SWITCH OPERATING APPARATUS Herbert L. Bone, Forest Hills, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application January 17, 1950, Serial No. 139,005

8 Claims.

My invention relates to railway switch operating apparatus, and particularly to a novel and improved latching device incorporated into the circuit controller of a railway switch operating apparatus.

The present invention is an improvement on the Railway Switch Operating Apparatus shown in Letters Patent of the United States No. 2,082,142, granted to me on June 1, 1937.

Railway switch operating apparatus of the type described in the aforesaid patent provides means for moving a switch to and locking it in its normal or reverse position. The movement of the switch points to their normal or reverse position will rotate contact drums, forming a part of the circuit controller, from their normal position to their intermediate position, and then to their reverse position to control signals governing traffic movements over the switch. A train will sometimes trail a switch set and locked against it, forcing the switch points open. The movement of the switch points by the trailing train will move the point detector rod, normally provided in such switch operating apparatus as a part of the circuit controller, to rotate the corresponding contact drum to its intermediate position wherein a restrictive signal will be set.

Because of clearance requirements, the point detector rod is connected to the switch points some distance below the top edges of the points. Due to the rolling of the points about their lower edges when the switch is trailed, the lower edges of the points may not be displaced as far as the upper edges of the points. Consequently, the point detector rod fixed nearer to the lower edges of the points will not be displaced in accordance with the actual displacement of the top edges of the points. The top edges of the points may thus be open an amount greater than the maximum permissive opening of the points, but the point detector rod being displaced to a lesser degree may not operate the circuit controller to indicate an unsafe condition existing over the trailed switch. Actually, the opening of the switch points at the top edges may be sufficient to be extremely dangerous for subsequent high speed train movements over the trailed switch.

In order to insure that an open switch point will be detected, the latching mechanismpf the aforesaid patent was so constructed that if a train trailed the switch while it was locked, the latching mechanism retained the circuit controller contacts in their respective signal positions until the latching mechanism was subsequently released by a maintainer. Thus, even though 2 the switch points returned to their proper positions after the train had trailed through the switch, the signals governing traffic over the switch continued to display a restrictive indication until the maintainer released the contacts of the circuit controller. It was assumed that before the maintainer restored the latching mechanism he would inspect the switch points, and, if damaged, repair them, thus guarding against a dangerous condition due to damaged switch points.

However, it sometimes happens that latch mechanisms of this type become latched due to other causes than a trailing train, as, for example, when deposits of frost prevent the various parts from functioning in a proper manner, or when excessive vibration of the switch points causes the latch to trip. As a result of these false latchouts trains are sometimes unnecessarily delayed.

Accordingly, the principal object of my invention is to provide a simplified and improved latching mechanism that will retain the circuit controller contacts in their warning position after a locked switch has been trailed, the latching mechanism being restored to its unlatched position upon operation of the switch operating apparatus.

Another object of my invention is to provide a latching mechanism which may be readily altered so that manual operation of the latch is required to unlatch the latching mechanism after a latchout, or which may be further altered so that the mechanism is rendered inoperative.

My novel latching mechanism may be incorporated in the switch operating apparatus disclosed in my aforementioned patent in which two crank arms are moved in unison upon move- -ment of a motion plate from one extreme position to another extreme position, the movement of the crank arms rotating the contact drums of the circuit controller. A point detector rod connected to the switch points and movable therewith, cooperates with the aforesaid crank arms to rotate one or the other of said crank arms when the switch points remain or are forced open for any reason after the switch is locked.

The latching mechanism comprises a latch rod pivoted to one of the crank arms and a latch stud fixed to the other of said crank arms. The latch rod is provided with a bifurcated latch head to receive the latch stud, a spring interconnecting the two crank arms biasing the latch head against the latch stud to hold the latch rod in its unlatched position.

When a train trails the switch, the displacement of the switch points will move the point detector rod to rotate one of the crank arms, thereby increasing the distance between the crank arms. The latch head will drop and the latch rod will hold the crank arms apart. contact drum connected to the rotated crank arm will be rotated to an intermediate position and will be held. in that position by the latching device. The normal indication contacts controlled by the contact drum of the circuit controller will then be held open and a restrictive signal indication will result.

The

I further provide a cam follower for the latching mechanism which is secured to the underside of the latch rod directly over the motion plate, the cam follower cooperating with either of two concave cam surfaces in the top side of the motion plate. When a latchout occurs, the cam follower drops into one of the concave cam surfaces when the latch rod falls into its latching position. The parts are so formed that when the motion plate is moved by operation of the switch motor to reverse the position of the switch points, the cam follower and the latch rod are forced upwardly due to the camming action of the motion plate, moving the latch head into engagement with thestud in its unlatched position.

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

In the accompanying drawings, Fig. 1 is a top plan View showing a railway switch A actuated by switch operating mechanism B incorporating a latching device embodying my invention. Fig. 2 is an enlarged top plan view of a portion of the mechanism shown in Fig. 1, with the top plate l9 and circuit controller C removed-to better illustrate the construction. Fig. 3 is a front View of a portion of the mechanism shown in Fig. 2. Fig. 4.- is an enlarged top plan view of the circuit controller forming part of the mechanism shown in Fig. 1, the cover being removed to better illustrate the construction of the circuit controller and the novel latching device. Fig. 5 is a sectional view taken substantially on the line V-V of Fig. 4. Fig. 6 is a sectional view taken substantially along the line VIVI of Fig. 4 showing the latch in normal unlatched position. Fig. 7 is a sectional view similar to Fig. 6 except that the latch is in the latched position. Fig. 8 is a fragmentary sectional View taken along the line VIII-VIII of Fig. 4 showing the overlying rack bars of the circuit controller. Fig. 9 is a sectional view similar to-Fig.

-7 illustrating an optional arrangement of the latching device, manual resetting being required to unlatch the device. Fig. 10 is a view similar to Fig. 9 illustrating a second optional arrangement of the latching device, the latching device this position being inoperative. Fig. 11 is an enlarged view in isometric projection of the latch head of the latching device.

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

Referring first to Fig. 1, the reference character A designates a railway switch comprising two fixed rails l and 2 and two movable switch points 3 and 4. The fixed rails I and 2 are laid on tie plates 5 and are secured to crossties 6 in the usual manner. The switch points 3 and 4 are connected together by a front rod 1, a head rod 8, and a tie rod 9, and may be moved into a normal or a reverse position by means of a switch operating mechanism B which is connected with the head rod 8 through the medium of an operating rod I0 and the usual switch basket ll. When the switch occupies its normal position, in which position it is shown in Fig. 1, the switch point 3 engages the fixed rail I, and the switch point t is spaced a predetermined distance from the fixed rail 2. When the switch is reversed, however, the switch point 4 then engages the fixed rail 2 and the switch point 3 is spaced from the fixed rail l.

The switch operating mechanism B is mounted on a bed plate l2 which is secured to the ties 6 adjacent the outer side of the rail I, and in the form here shown, this mechanism comprises a base plate [3 (see Figs. 2 and 3), bolted to the bed plate I2, and carrying a longitudinally movable slide bar It which is guided between rollers l5 journaled on studs which project upwardly from the base plate. The slide bar It! is adapted to be reciprocated between two extreme'posi- -tions, and for this purpose the slide bar is 0peratively connected with the piston rod it of a fluid pressure motor M which is bolted to'the bed plate [2.

As best seen in Fig. 3, the slide bar l4 consists of an upper bar 14a and a lower bar Mb riveted together in superposed parallel spaced relation. A roller H is rotatably mounted between the bars Ida and Mb, and this roller coacts with an alligator jaw i3 which is journaled at its lower end in the base plate 13 and at its upper end in a top' plate [9. The top plate I9 is bolted to the base plate It in parallel spaced relation and serves to prevent vertical displacement of the slide bar is between its roller guides. The alligator jaw [S is operatively connected with the previously described operating rod ID in the usual and well-known manner.

In addition to carrying the roller IF), the slide bar [4 carries two locking dogs 20 and 2! which are attached to the upper and lower bars Ida and lb, respectively, and which cooperate with suitable notches 22 and 23, respectively, formed in an adjustable lock rod L. The lock rod L is of the usual and well-known construction, and is connected to the front rod 1 of the switch A in the usual manner. I

The parts which have thus far been described are in widespread use, and their operation is Well understood, a detailed description of the switch operation being given in my aforesaid patent. As more fully set forth in my United States Patent No. 2,082,142, the signals governing the trafiic over the switch A are controlled by an indication circuit controller C enclosed in a suitable casing 24 (see Figs. 4 and 5) which is bolted to the right-hand end of the base plate 13. Journaled' in a frame 25 secured to the bottom wall 26 of the compartment 2? in the casing 24 are two contact drums 28 and 29. Mounted on an insulation portion of the contact drums 23 and 29 are a plurality of contact members 30 and 3|, respectively, adapted to be engaged by the contact fingers 32 and 33. The contact fingers 32 and 33 are fixed in a suitable manner to insulating members 34 fixed to, the frame 25 on both sides of the drums 28 and 29. The contact drums 28 and 29 are each adapted to be rotated between an intermediate and two extreme positions by means of gear wheels 35 and 36 secured to the ends of the contact drums 2 8 and 2i, respectively. The gear wheel 35 meshes with the rack teeth 31 of a rack bar 38, while gear wheel 36 meshes with the rack teeth '39 of a similar rack bar 40.

The two rack bars 38 and 49 are slidably mounted side by side in the compartment 21 for reciprocation between two extreme positions, and the ends of these rack bars opposite to those in which the rack teeth are out extend into the compartment 4| of the casing 24. The ends of the rack bars 38 and 49 are flattened and offset, the offset portion of rack 40 being disposed above the plane of the offset portion of rack 38 (Fig. 8) so that a considerable amount of clearance is provided between the rack bars at the offset portions. The ends of the flattened ofiset portions of the rack bars 38 and 40 are slotted, the two slots being so disposed that their open ends face in opposite directions. The slotted end of the rack bar 38 cooperates with a pin 42 which is mounted in the bifurcated end of a crank arm 43 while the slotted end of the rack bar 40 cooperates with a pin 44 mounted in the bifurcated end of a crank arm 45. The pins 42 and 44 are similar, the pins being round at their ends to permit free rotation in the bifurcated ends of the crank arms, but the portion of the pins cooperating with the slotted offset portions of the rack bars being fiat on two sides to provide a sliding fit with the slotted ends.

The crank arm 43 is secured to the upper end of a vertical rockshaft 46 journaled in the compartment 4| on one side of the slide bar l4, while the crank arm 45 is secured to the upper end of a vertical rockshaft 41 journaled in the compartment 4| on the opposite side of the slide bar M. It will be apparent from the foregoing description that rotation of the rockshafts 46 and 41 will cause longitudinal movement of the rack bars 38 and 48 which in turn will cause rotation of the contact drums 28 and 29, respectively.

The two rockshafts 46 and 41 are operatively connected with the slide bar l4, to be oscillated thereby, in the following manner. Formed integrally with the rockshaft 46 directly below the crank arm 43 is a crank arm 48 (Fig. 6), and formed integrally with the rockshaft 41 directly below the crank arm 45 is a crank arm 49. The crank arms 48 and 49 are of relatively wide web-like construction (Fig. 4) and each extends substantially parallel to the slide bar H. A

roller 50 is dependently attached, by means of a bolt 5| and a nut 52 to the crank arm 48, and a roller 53 is likewise attached by means of a bolt, 54 and a nut 55 to the crank arm 49.

The roller 53 cooperates with two recesses (LI and a2 (see Fig. 2) formed in one side edge of a motion plate 56 which is carried by the slide bar I4, and the roller 59 similarly cooperates with two recesses bl and b2 formed in the side of the motion plate 56 opposite to that in which the recesses al and a2 are formed. A spring .51 is stretched between two upstanding pins 58 and 59 provided on the crank arms 48 and 49, respectively, and this spring constantly biases the rockshafts to such positions that the rollers 50 and 53 will enter the associated recesses in the motion plate whenever these recesses are in alignment with the rollers, unless the rollers are prevented from doing so by the point detector mechanism hereinafter described.

- The recess a| in the motion plate 56 is relatively short and is so disposed that this recess "w'ill 'align'with the roller'53 when the slide bar l4 occupies its extreme normal position in which it is shown in the drawing. The recess a2 joins the right-hand end of the recess al, as viewed in Fig. 2, and is of such length that this latter recess will align with the roller 53 when the slide bar I4 occupies any position except its extreme normal or its extreme reverse position. The recess a| is approximately twice as deep as the recess (12, and it will be apparent, therefore, that when the roller 53 enters the recess al, the rockshaft 41 will be rotated, in a counterclockwise direction, as viewed in Fig. 4, to one extreme position; that when the roller 53 is forced out of both recesses al and a2, the rockshaft 41 will be rotated in a clockwise direction to another extreme position; and that when the roller 53 enters the recess a2, the rockshaft 41 will be rotated to an intermediate position approximately midway between its two extreme positions.

The recess b| is similar to the recess al, but 7 is so disposed that this recess will align with the roller 50 when the slide bar |4 occupies its extreme reverse position. The recess b2 is likewise similar to the recess a2, and is so disposed that this recess will align with the roller 58 when the slide bar occupies any position intermediate its two extreme positions. It follows that the rockshaft 46 will be rotated to one extreme position whenthe roller 58 enters the recess b|, to another extreme position when the roller 58 is forced out of both recesses, and to an intermediate position approximately midway between its two extreme positions when the roller 50 enters the recess b2.

The recesses a|, a2, bl and D2, in addition to being proportioned and disposed in the man-'- ner above described, are so designed that-any rotation of the rockshafts 46 and 41 due to engagement of the rollers 53 and 50 with these recesses will be equal and opposite. The crank arms 48 and 49 are thus rotated in unison by the movement of the slide bar l4.

The contact drums 28 and 29 are each adapted to be rotated from one extreme position toan intermediate position, and from the intermediate position to a second extreme position by the rotation of the crank arms 48 and 49, respectively. With the switch point 3 in its normal position against the fixed rail the slide bar I4 is in its extreme normal position as illustrated in Figs. 1-5. The motion plate 56 will also be in its extreme normal position, the roller 59 of crank arm 48 engaging the motion plate while roller 53 is within the recess al. The crank arm 48 will have been rotated in a counterclockwise direction by the motion plate 56 as viewed in Fig. 4, to move the rack bar 38 to the right. The contact drum 28 will thus have been rotated in a counterclockwise direction when viewed from the bottom in Fig. 4 to the position illustrated. The crank arm 49 will also have been rotated in a counterclockwise direction by the motion plate to move the rack bar 40 to the left as seen in Fig. 4. The contact drum 29 will thus have been rotated in a clockwise di-' rection when viewed from the bottom in Fig. 4 to the position illustrated.

Operation of the motor M to reverse the switch will move the slide bar l4 from its extreme normal position illustrated in Figs. 1-5 to the left, through an intermediate position, to its extreme reverse position. The slide bar M will carry the motion plate 56 in the same 'direction. The crank arms'48 and 49 will be rotatedin' clockwise 7 direction (Fig. 4) in the manner described, to move the rack bar 38 to the left and the rack bar 40 to the right, respectively. When the slide bar [4, is in its intermediate position, the rollers 50 and 53 of the crank arms t8 and 49, respectively, will be in their respective recesses b2 and a2 in the motion plate 56. The racks 38 and 4!] will move the contact drums 23 and 29, respectively, to their intermediate positions. The continued movement of the slide bar It to itsextreme reverse position will cause the crank arms 48 and 49 to rotate still further in a clockwise direction (Fig. 4) to move the rack bars 38 and 39. The rack bar 38 moving toward the right, as seen in Fig. 4, will rotate the contact drum in a clockwise direction when viewed from the bottom in Fig. 4, to its extreme reverse position, while the movement of the rack bar 39 to the right will rotate the contact drum 29 in a counter-clockwise direction, when viewed from the bottom in Fig. 4,, to its extreme reverse position.

As more fully set forth and described in my aforesaid United States Patent No. 2,082,142, several of the contact members 30 and contact fingers 32 will engage when the contact drum 28 is in the extreme normal position illustrated, several other contact members 39 and contact fingers 32 will engage and others disengage when the contact drum 28 is rotated to its intermediate position, while other contact members so and contact fingers 32 are engaged and others disengaged when the contact drum 28 is rotated from its intermediate position to its extreme reverse position. The contact members 3! and contact fingers 33 will also engage and disengage as the contact drum 29 is rotated from the extreme normal position illustrated to its intermediate position and from its intermediate position to its extreme reverse position. Simultaneous rotation of the contact drums 28 and 28 in opposite directions from their extreme reverse positions to their intermediate positions, and from their intermediate positions to their extreme normal positions will reverse the operation of the contact members and fingers. As set forth in the aforementioned patent, the contact members 30, 3| of the contact drums 28, 29 and the contact fingers 32, 33 may be utilized in a variety of wellknown signal circuits to control the traffic over the switch A. Since these circuit making elements form no part of the present invention, the brief description of their operation will suffice for the present application. For further details of construction and operation of the circuit controller thus far described, reference may be made to my aforementioned patent.

The circuit controller C also comprises a point detector mechanism for controlling the rockshafts 46 and 41 in accordance with the-positions of the switch points and i independently of the control of these rockshafts by the slide bar It.

To this end two additional crank arms E0 and BI (see Figs. l and 6) are secured to the lower ends of the rockshafts 48 and 47, respectively, and are provided at their outer ends with rollers 62 and 63 which cooperate with an annular recess 64 in a point detector rod D of the usual and well-known type. Thepoint detector rod D is slidably mounted in suit'ableguides provided in the base plate l3 and is adjustably secured in the usual manner to the normally closed point 3 of the switch A. The recess 64 is'so designed, and the parts are so proportioned, that this recess will align with the roller 63 when the switch point 3 is tight against the stock rail I, and with the roller 62 when the switch point 4 is tight against the stock rail 2. The parts are further proportioned that the roller 63 will enter the recess 64 when and only when the roller 53 enters the recess al in the motion plate 56, and roller 62 will enter the recess 64 when and only when the roller enters the recess bl in said motion plate. The parts are further proportioned that if either roller 62 or 63 is forced out of the recess. :64 due to the movement of the point detector rod D, the associated rockshaft 46 or 41 will be rotated from the extreme position which it then occupies to its intermediate position.

As for example, the clockwise rotation of the rockshaft 41 (Fig. 4) upon movement of thepoint detector rod D from its extreme position illustrated due to an open switch point, will move the corresponding rack bar 4!] to the right to rotate the drum 29 from the extreme position illustrated to its intermediate position. The contacts controlled by the drum 29 will thus be actuated in the manner set forth in the aforesaid patent to provide, a restrictive indication of the open switch points.

In the aforementioned patent, a latching device was provided to insure that an indication would be given when a train trailed the switch regardless of whether the switch points were damaged by the trailing train or not. Such a latching device required the manual restoration thereof by a maintainer so that the restrictive signal governing traflic over the switch could be cleared.

Circumstances other than a trailing train could cause a latchout of the circuit controller. As, for example, in freezing weather frost deposits on the bearings for the shafts 46 and 4'! supporting the crank arms 48 and 49 may develop sufiicient friction to prevent the crank arms from following the motion plate at the end of the stroke. Referring to Fig. 4, it will be appreciated that as the motion plate is moved from its extreme reverse position to the extreme normal position illustrated, the crank arm 48 will be rotated counterclockwise by the positive cam.- ming action of the motion plate 58. The crank arm 39 on the other hand is rotated in a counterclockwise direction by the action of the spring 5'1. Thus any friction in the. bearing for the crank arm shaft 47 will retard the rotation of the crank arm 49 by the spring 51. Consequently, the distance between the two crank arms will be increased to permit the latch rod '65 to drop, to latch the crank arms in the abnormal position. Another cause for improper latchouts might be the excessive motion of the switch points during the passage of a train over the switch developing sufficient inertia forces to trip the latch, the point, detector rod under such circumstances being moved to rotate either of the crank arms 48 or 49.

,A novel latching device is now provided by I which the undesirable effects of false latchouts are minimized to the extent that the latching device is made self-restoring under proper conditions, and in which means are incorporated whereby the latching device may be altered so that manual restoration by a maintainer may be required upon a latchout, or alteration may be made so that the latching mechanism is entirely inoperative as the circumstances and conditions warrant.

To this end, there is provided a latch rod 65 pivotally connected at one end to. the webbed crank arm 48 as by a bolt 66. The pivoted end of the rod is slightly enlarged (Fig. 4) and formed with convex upper and lower surfaces 65a and 65b (Fig. 7), an opening 650 receiving a flanged sleeve 66a and the bolt 66. As will hereinafter be apparent, the opening 650 is slightly larger than the sleeve 66a and the upper and lower surfaces 65a, 65b are made convex to permit'the latch rod 65 to swivel vertically as Well as horizontally. The free end of the latch rod is threaded as at 61, and has threaded thereon a latch head 68. The end of the latch head is bifurcated (Fig. 11) to form a slot 69 therein having a substantially vertical-concave surface 18. About half of the lower portion of the latch head end is milled away to form steps or shoulders H on the bifurcated ends of the head, while the upper and lower edges of the slot 69 are beveled to form the sloping surfaces 12 and 13 in the upper and lower faces of the latch head.

The latch head 68 cooperates with a latch stud 14, the head 75 of said stud being received within a recess 16 formed in the webbed crank arm 49. The latch stud 14 is provided with shank portions of different diameters, the shank portion I1 adjacent the head 15 having a larger diameter than the end shank portion 18 which is threaded near its end. The end shank portion of the latch stud is received in an appropriate opening in an inverted L-shaped bracket 19 integral with the top surface of the webbed crank arm 49. The shoulder formed by the larger diameter shank portion 11 is drawn up tightly against the underside of the bracket 19 by means of a nut 80 threaded on the projecting end portion 18 of the latch stud.

The shank portion 11 of the latch stud 14 is received within the slot 69 of the latch head 68. In its normal unlatched position, as shown in Fig. 6, the concave vertical surface 18 of the latch head engages the shank portion 11 of the stud due to the bias of the spring 51, the beveled surface 13 of the latch head resting upon the beveled shoulder 81 formed on the latch stud head 15. The arcuate beveled surface 8| f the latch stud head is of the same camber as that of the latch head surface 13 so that anadequate support is provided for the latch rod 65. The overall length of the latch rod and latch head is adjusted by screwing the latch head on the threaded end 6! of the latch rod and tightening the same by a lock washer 82 and jam nut 83, so that the webbed crank arms 48 and 49 are held in aposition in which a small clearance is maintained between the motion plate 56 and the rollers 50 and 53 carried by said crank arms.

counterclockwise rotation of the webbed crankarm 48 or clockwise rotation of the webbed crank surface 18 engages the latch stud head 15 as illustrated in Fig. 7. The webbed crank arms 48 and 49 will be held in this latched position by the latch rod 65 until the latch rod is'lifted so that the beveled surface 13 of the latch head is again seated on the beveled shoulder 8| of the latch stud 14. The rotation of the crank arm 48 or 49 due to the movement of the detector rod will rotate the contact drum 28 or 29 to an intermediate position to close a restricted signal circuit. Unlatching of the latch rod 65 will permit the rotation of the contact drum from the 10 intermediate position to its extreme position due to the action of the spring 51 on the crank arms 48 and 49 to clear the restrictive signal.

Means are now provided to lift the latch rod 65 from its latched position to its unlatched position upon movement of the motion plate 56 from its extreme normal position toward its extreme reverse position, or from its extreme reverse position toward its extreme normal position depending upon the position in which the latch rod 65 latched the two webbed crank arms 48 and 49.

To this end, the latch rod 65 is provided with a dependent cam member 84 fixed to said latch rod as by bolts 85. The lower end of said cam member is provided with an arcuate camming surface 86, a small clearance being maintained between the camming surface 86 and the top surface of the motion plate 56 when the latch rod 65 is in its unlatched position as shown in Fig. 6. The motion plate 56 is provided with two concave camming surfaces 8! and 88 (Figs. 3 and 5), the camming surface 88 being in alignment with the dependent cam member 84 when the motion plate is in its extreme normal position, and the camming surface 81 being in alignment with the cam member 84 when the motion plate is in its extreme reverse position. It will be noted that the lower face of the motion plate 56 is provided with similar concave camming surfaces. This provision is made so that the motion plate may be turned over and used when the top surface becomes worn or scored for any reason.

If we assume that the motion plate 56 is in its extreme normal position as illustrated in the drawings, the cam member 84 will be in alignment with the concave camming surface 88 and the detector rod recess 64 will be engaged by the roller 63 on the rockshaft 41. The two webbed crank arms 41 and 48 will be in the position as illustrated with the latch rod 65 in its unlatched position. The contact drum 29 will be in its extreme normal position to provide the normal signal indications for trafiic movement over the switch A.

A train trailing the switch will force the closed switch points open to move the point detector rod D. The roller 63 will be moved out of the detector rod recess 64, thereby rotating the rockshaft 41 and the crank arms 45 and 49 in a clockwise direction (Fig. 4) against the bias of the spring 51. The latch rod head 68 will be partially withdrawn from latch stud 14, permitting the latch rod 65 to fall, the shoulder H on the latch rod head now engaging the conical shoulder 8| on the latchstud, the arcuate vertical surface 19 engaging the latch stud head 15. The cam member 84 will thus drop, the camming surface 86 engaging the concave camming surface 88. The two webbed crank arms 48 and 49 will be maintained in this latched position even though the switch point 3 maytions, the slide bar i4 carrying the motion plate.

56 will be moved to the left as viewed in Figs. 1-5. The movement of the motion plate will lift the latch rod 65 due to the camming action of'the cam surface 88 of the motion plateand the cam surface 86 of the cam member. The latch rod 65 will be'lifted suificiently for the edge of the beveled surface 73 to engage the edge of the conical shoulder 8! on the latch stud M. Due to the bias of the spring 51, the latch rod 65 will be lifted an additional degree by the upward camming action of the two sloped surfaces so that the cam surface of the dependent cam member 84 is clear of the topsurface of the motion plate 56. The latching device will then be in its unlatched position, as illustrated in Fig. 6, the crank arms 48 and 49 again being operated in unison by the movement of the motion plate 56.

If the switch is damaged seriously, it will not lock up when operated because the lock dog 26 (2|) will not enter the lock rod notches 22 (23). Accurate positioning of the switch points is necessary due to the small tolerances provided, before the locking dogs of the slide bar may enter their respective lock rod notches. If the motor M is operated to move the switch points, the crank arms 48, t9 will be unlatched, but the switch cannot be operated to .its extreme position if the locking dogs fail to enter their respective lock rod notches. The slide bar M can be moved no further than its intermediate position, in which position the crank arms 43 and 49 are also in their intermediate position. Consequently, the contact drums 28, 29 will be in their intermediate positions to set a restrictive signal for traffic moving over the switch A.

Should the switch be damaged by a trailing train to the extent that the locking dogs cannot be withdrawn from the lock rod notches, the point detector rod will have been moved by the trailed switch points to move either the crank arm '48 or the crank arm 49 to an intermediate position in which the corresponding contact drum will set a restrictive signal. The movement of the point detector rod by the trailed switch points will cause the latching arrangement described to latch out the two crank arms 48, 49.

Should a switch be trailed and the switch not be seriously damaged, the operation of the motor M to move the switch points will unlatch the latching arrangement in the manner described, and the switch may be moved to its reverse and normal positions provided the locking dogs on the slide bar enter their respective lock rod notches. Under such circumstances, the required operation of the motor M to clear the restrictive signal set by the latchout will serve as a tell-tale that the switch had in fact been trailed.

A false latchout of the character indicated hereinabove, is readily cleared by operation of the motor M to reverse the position of the switch points. The movement of the motion plate .will cause the latch rod to lift permitting the return of the crank arms to their normal position to clear the restrictive signal set. Since such false latchouts are not the result of a trailed switch, the switch movement is in working order and the locking dogs will enter their respective notches in the locking rod.

Under certain operating conditions, or possibly under certain operating regulations, it might be advantageous to require manual restoration of the latching device after a latchout occurs due to any reason. The present latching device described may readily be altered to providea latching device requiring manual unlatching. The two bolts 85 holding the cam member Mto the latch rod 65 are unscrewed and the cam member 84 inverted (Fig. 9) on the latch rod and then bolted to the latch rod in an upstanding position. The cam member will then serve as a hand piece 12 or handle forlifting the latch-rod to its unlatched position.

With the cam member 84 fixed to the latch .rod 65 in an upstanding position, the latch rod will drop to its latching position in the manner previously described in the event the switch A is trailed. Restrictive signals over the switch will then be set and maintained by the circuit controller until the latch rod is again restored to its unlatched position. Since the cam member84 in its inverted position no longer cooperates with the camming surfaces 87 and 88 in the motion plate 56, it will be necessary for a maintainer .to lift the latch rod 65 before normal operation of the switch machine A may be had.

Under other circumstances or regulations, it may be necessary to place the latching device in an inoperative position. In such event, the bolt v66 may be unscrewed and the assembly of the latch rod 65, camming member 84, and latch head 68 turned over (Fig. 10) and reassembled on crank arm 48 in an inverted position by bolt 66. The latching device may also be made inoperative by rotating the latch head 68, 180 degrees on the latch rod so that the beveled surface 12 in the upper surface of the latch head is facing downwardly and resting on the shoulder 18! of the latch stud 14. With the latching device inverted, the outward rotation of either crank arm 43 or due to the operation of the point detector rod D will not withdraw the latch head 68 from the latch stud 14. Consequently, the latch rod 65 and the latch head 68 will be held in the unlatched position by the shoulder 6| of the latch stud at all times.

Although I have herein shown and described only one form of latching device for a railway switch machine 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 spiritand scope of my invention. Y

Having thus described my invention, what I claim is:

v 1. The combination with a motion plate mov-' able to two extreme positions, two members normally movable in unison from one extreme position through an intermediate position to a second extreme position by said motion plate in moving from one extreme position to its other extreme position, and means for moving one-of said movable members to its intermediate position when said motion plate and said members" are in either of their extreme positions; of a latch stud for one of said movable members, said stud having an enlarged portion and a cam-sur said stud when one of said movable members is moved to its intermediate position by said moving means, said arcuate surface engaging the enlarged portion of said latch stud to hold said member in its intermediate position.

2. The combination with a motion plate mov-' able to two extreme positions, two members normally movable in unison from one extreme position through an intermediate position to a second extreme position by said motion plate inmoving from one extreme position to its other extreme. position, and means for moving one of said movable member to its intermediate position when said motion plate and said members are in either of their extreme positions; of a latch stud for one of said movable members, said stud having an enlarged portion and a cam surface on said enlarged portion, a latching member pivoted to the other of said movable members, a cam surface on said latching member normally engaging the cam surface of said stud, an arcuate surface and a shoulder on said latch member; said shoulder engaging the cam surface of said stud when one of said movable members is moved to its intermediate position by said moving means, said arcuate surface engaging the enlarged portion of said latch stud to hold said member in its intermediate position, a cam on said latching member and cooperating camming surfaces on said motion plate, the movement of said motion plate from an extreme position bringing said gammi-ng surfaces into engagement with said latching member cam to disengage the arcuate surface of said latching member from said latch stud enlarged portion and reengage the latching member cam surface with the latch stud cam surface to release the movable member held in its intermediate position.

3. The combination with a motion plate movable to two extreme positions, two members rotatable in unison by said motion plate from one extreme position through an intermediate position to a second extreme position, the spacing between the rotatable members remaining constant, and means for rotating one of said roatable members to its intermediate position without simultaneously rotating the other of said rotatable members; of a latching member pivoted to one of said rotatable members,- a latch stud for the other of said rotatable members, a head on said latch stud, camming surfaces on said latching member and on said latch stud head cooperating with each other when the spacing between the rotatable members remains constant, and a surface on said latching member to engage said latch stud head when the spacing between said rotatable members increases due to the rotation of one of said members by the rotating means to hold said member in its abnormal position.

4. The combination with a motion plate movable to two extreme positions, two members rotatable in unison by said motion plate from one extreme position through an intermediate position to a second extreme position, the spacing between the rotatable members remaining constant, and means for rotating one of said rotatable members to its intermediate position without simultaneously rotating the other of said rotatable members; of a latching member pivoted to one of said rotatable members and extending substantially transversely of and above said motion plate, a latch stud for the other of said rotatable members, said latching member cooperating with said latch stud when the spacing between said rotatable members increases due to the rotation of one of said members by the rotating means to hold said rotatable memhere in an abnormal position, a dependent cam on said latching member, and a cam surface on said motion plate cooperating with said latching member cam when said latching member and said latch stud hold said rotatable members in an abnormal position, the movement of said motion plate from an extreme position causing the depending cam to lift the latching member to release the rotatable members from their abnormal position.

5. The combination with a motion plate mov-- able to two extreme positions, two members rotatable in unison by said motion plate from one extreme position through an intermediate position to a second extreme position, the spacing between the rotatable members remaining constant, and means for rotating one of said rotatable members to its intermediate position Without simultaneously rotating the other of said rotatable members; of a latching member pivoted to one of said rotatable members and extending substantially transversely of and above said mo-' tion plate, a bifurcated latch head for said latching member, an arcuate surface on said latch head, a cam surface on said latch head, a shoulder on said latch head; a latch stud fixed to the other of said rotatable members, an enlarged portion on said latch stud, a cam surface on the enlarged portion of said latch stud; said latch stud being received by the bifurcated latch head of said latching member, the cam surface on said latch head resting on the cam surface of said latch stud when the two rotatable members are in a normal position with the spacing therebetween remaining constant, said latch head shoulder dropping to engage the latch stud cam surface when the distance between the two rotatable members increases due to the rotation of one of said rotatable members by said rotating means, the arcuate surface on said latch head engaging the enlarged portion of said latch stud to hold said rotatable members in an abnormal position.

6. The combination with a motion plate movable to two extreme positions, two members rotatable in unison by said motion plate from one extreme position through an intermediate position to a second extreme position, the spacing between the rotatable members remaining constant, and means for rotating one of said rotatable members to its intermediate position without simultaneously rotating the other of said rotatable members; of a latching member pivoted to one of said rotatable members and extending substantially transversely of and above said motion plate, a bifurcated latch head for said latching memher, an arcuate surface on said latch head, a cam surface on said latch head, a shoulder on said latch head; a latch stud fixed to the other of said rotatable members, an enlarged portion on said latch stud, a cam surface on the enlarged portion of said latch stud; said latch stud being received by the bifurcated latch head of said latching member, the cam surface on said latch head resting on the cam surface of said latch stud when the two rotatable members are in a normal position with the spacing therebetween remaining constant, said latch head shoulder dropping to engage the latch stud cam surface when the distance between the two rotatable members increases due to the rotation of one of said rotatable members by said rotating means, the arcuate surface on said latch head engaging the enlarged portion of said latch stud to hold said rotatable members in an abnormal position, a depending cam on said latching member, the lower edge of said cam being above the upper surface of said motion plate, a concave camming surface on said motion plate aligned with said cam when said motion plate is in an extreme position, said latching member cam registering with the camming surface of said motion plate when said latching head shoulder engages the latch stud camming surface, the movement of said motion plate from the extreme position causing the motion plate camming surface to lift said 15 a latching member cam to reengage the latch head cam surface with the latch stud cam surface to release the rotatable members from their abnormal position.

16 tatable in unison by said motion plate from one extreme position through an intermediate po sition to a second extreme position, the spacing between the rotatable members remaining coni 7. Ihe combination with a motion plate movstant, and means for rotating one of said roable to two extreme positions, two members rotatable in unison by said motion plate from one extreme position through an intermediate position to a second extreme position, the spacing tatable members to its intermediate position Without simultaneously rotating the other of said rotatable members; of a latching assembly pivoted to one of said rotatable members comprisbetween the rotatable members remaining con 0 ing a latch rod, a latch head on the end of said stant, and means for rotating one of said rotatable members to its intermediate position without simultaneously rotating the other of said rotatable members; of a latching assembly removably rod and a dependent cam member removably fixed to said rod; a latch stud for the other of said rotatable members, said latch head cooperating with said latch stud when the spacing bepivoted to one of said rotatable members comtween said rotatable members increases due to prising a latch rod, a latchhead on the end of said'rod and a dependent cam memberon said the rotation of one of said rotatable members by the rotating means to hold said rotatable memrod; a latch stud for the other of said rotatable' bers in an abnormal position, and a cam surface members, said latch head cooperating with said on saidnnotionplite cooperating with said delatch stud when the spacing between said ro- 20 pendent cam when said latch headland said latch tatable members increases due to the rotation of one of. said rotatable members by the rotating means to hold said rotatable members in an abnormal position, and a cam surface on said mostud hold said rotatable members infiabnormal position, the movement of said motion plate from an extreme position causing the cam surface to lift the dependent cam to lift the latch rod and tion plate cooperating with said dependent cam latch head for releasing the rotatable members when said latch head and said latch stud hold said rotatable members in an abnormal position,

nnthe movement of said motion plate from an extremeposition causing the cam surface to lift the from their abnormal position, said dependent cam member being adapted to be fixed in an upstanding position on said latch rod in which said cam member is inefiective to lift said latch rod dependent cam to lift the latch rod and latch upon mQVSment 0f S d motion p head for releasing the rotatable members from their abnormal position, said latching assembly being adapted to be pivoted to said rotatable member in an inverted position making said latching assembly inoperative to hold said rotatable members in an abnormal position.

8." The combination with a motion plate movable to two extreme positions, two members ro- HERBERT L. BONE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,989,128 Bone Jan. 29, 1935 2,982,142 Bone June 1, 1937

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