US1399258A

US1399258A - Electric lock for power-operated switch-machines

Info

Publication number: US1399258A
Application number: US351098A
Authority: US
Inventors: Winthrop K Howe
Original assignee: General Railway Signal Co
Current assignee: SPX Corp
Priority date: 1920-01-13
Filing date: 1920-01-13
Publication date: 1921-12-06
Anticipated expiration: 1938-12-06

Description

W. K. HOWE.

ELECTRIC LOCK FOR POWER OPERATED SWITCH MACHINES.

APPLICATION FILED JAN-13 1920. 1,399,258. Patented Dec. 6, 1921. I I 3 SHEETSSHEET If) LO I 0 9 m m m a= u 2 II w. K. HOWE. ELECTRIC LOOK FOR POWER OPERATED SWITCH MACHINES.

APPLICATION FILED JAN. 13. I920.

Patented Dec. 6,

3 SHEETS-SHEET 2.

mm "3 I s S g 8 mm mm om 8 F If 6 mm 3 8 Ma 0 T mm ow W. K. HOWE. .ELECTRIC LOCK FOR POWER OPERATED SWITCH MACHINES.

APPLICATION Flu-:0 JAN. 13, 1920.

1,399,258. Q Patented Dec. 6,1921

3 SHEETSSHEET 3.

ZATTORNEY.

UNITED STATES 'WINTHROP K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY PATENT OFFICE.

SIGNAL COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

ELECTRIC LOCK FOR POWER-OPERATED SWITCH-MACHINES.

Application filed January 13, 1920.

T0 (171 10720112. it may com-cm.

Be it known that I, \VnvTHRor K. Hown, a citizen of the United States, and resident of the city of Rochester, in the county of Monroe and State of New York, have invented a new and useful Electric Lock for Power-Operated Switch-Machines, of which the following is a specification.

This invention relates to power interlocking systems for railroads, and more particularly to improvements in detector locking used in connection with power operated switch machines for preventing the switch being thrown under atrain or directly in front of it.

In accordance with my invention, it is proposed to prevent such improper operation of a switch machine by employing an electric lock which is governed by the usual detector track circuit associated with the switch, and which will lock the parts of the switch machine against movement when said track circuit is occupied. My present invention relates more especially to the construction and manner of control of such an electric lock.

One object of the invention is to economize in energy by providing a normally deenergized electric lock which is automatically picked up to release the switch machine when power is applied to operate said machine provided the detector track circuit is then unoccupied.

Another object is to provide anelectric lock which will not lock up the switch machine in mid-stroke, in order that the switch machine, after having commenced its cycle of operation, will be able to complete its cycle, even thoiwh a train in the meantime comes into the detector track circuit.

A still further object is to provide suitable arrangements whereby the energy for operating the electric lock may be derived from the main battery or other source of current at the tower, thereby avoiding local batteries at the switch for the purpose of operating the electric look.

A still further object is to provide a suitable manually operable device enabling the lock to be released and permit the-switch machine to be cranked over by hand, together with automatic mechanism preventing careless manipulation of this device in a .way to allow a switch'to' be improperly thrown under a train by power.

Specification of Letters Patent Patented Dec. 6, 1921.

Serial No. 351,098.

Other objects and advantages of my invention will be pointed out hereinafter, and the novel features are set forth in the accompanying claims.

In describing the invention in detail, reference will be made to the accompanying drawings in which like reference characters designate corresponding parts in the several views, and in which Figure 1 is a diagrammatic View, partly in perspective and with some parts broken away or spread apart for clearness, which shows the principal operating parts of a switch machine of well known construction having an electric lock and associated devices embodying my invention applied thereto. the various parts being shown more with the view of making their functions and operations easily understood, than with the idea of showing the exact construction and arrangement of parts which would be preferably employed in practice;

Fig. 2 is a circuit diagram for the switch machine and its locking mechanism; and

Figs. 3, 4 and 5 are fragmentary views showing modified circuit arrangements for energizing the electric lock.

I have illustrated my invention in connection with one type of an electrically operable switch machine, similar to that disclosed, for example, in my prior Patent No. 1288.595, dated December 24, 1918, but it should be understood that my invention may be applied to any type of power operated switch machine or switch and lock movement by making the appropriate changes in mechanical details.

Referring to Fig. 1, the stock rails of a conventional switch are designated 1, and the movable switch points 2. These switch points 2 are connected to a throw bar T and a lock rod LR of the switch machine, these parts being shown separated and to different scales for convenience and clearness. The switch machine is operated by an electric motor M of any suitable type, which is shown as a series wound direct current motor having an armature 3 and a field 4. The

armature shaft of the motor. M drives a main gear 5 journaled on a fixed stud 6 which drives a shaft 9 through a friction clutch 10 "(shown inclosed); a pinion 11 on and at 0t said shaft 9 meshin with a gear 12 on .a second shaft 13; an a pinion. 14 on said second shaft meshin with x the main ear 5. The main gear 5 1s rotated in one direction or the other to reverse the switch points I with the edges of a laterally opening jaw or cam in the throw rod T, and acts to reciprocate said throw rod as the. main gear 5 is rotated first in one direction and then in the other. Extending lengthwise of the switch machine is a locking plunger LP which is uided at one end by ablock 20 er points in its length by suitlugs (not shown). This locking plunger P is provided with an enlarged head 21 in which is formed .a cam slot 22 of a general elliptical shape, the lower roller 17 being disposed to cooperate with the edges of this cam slot and reciprocate said locking plunger as the main ear 5 is rotated. The locking plunger i'P carries a lock dog 23 arranged to engage behind

shoulders

24 and 24 on the throw bar T; and another lock dog 25 fastened to said locking plunger is arranged to enter normal and reverse notches rod LR, thereby holding the throw bar and the lock rod against movement and locking the switch points. The lock rod LR is shown as made up of two bars, which in practice are made relatively adjustable by suitable means (not shown) for the purpose explained in my prior patent above mentioned.

The circuit controller operation of the switch machine comprises in general two units or groups of contacts and their operating means, designated as a whole 0 and P, one for controlling the operating and indication circuits (hereinafter termed the operating circuit controller), and the other for controlling thev circuits of the pole changer coils (hereinafter termed the pole changer coil controller). Each -'unit comprises a plurality of lfixed contact springs or-fingers, as 26,-arranged .in rows along opposite sides of the machine and carriedby suitable fixedbars 27 of insulatlng material. Two separately movable blocks or contact carriers 28 and 29 are arable for governing the ranged to be shifted back and forth from one side of theinaehine to the other. Each of these 'contactfcarriers has a panel of i'nsulating material, 30 and 31, respectively, to which are fastened contact strips, as 32, adapted to bridge pairs of the contact (not shown) in the lock forms a springs 26. The contact carrier 28 of the operating circuit controller 0 is supported by the cores 33 of the normal and'reverse

pole changer coils

34 and 35,. and is shifted back and forth by an arm 36 loosely mounted on a vertical shaft 37 and having a jaw straddling apin 38 connected to said contact carrier. Thus, contact carrier 28 may be shifted electrically by the .pole changer coils 34 and-3 5, or mechanically by a con-' tact shifter designated as a whole CS, The contact block 29 of the pole changer coil controller P is o eratively connected to the contact shifter C by a pm 39 anda jaw .40 integral with said contact shifter.

The contact shifter CS is an irregular shaped piece, comprising a bottom plate 41,

carrying normal arid reverse 0 crating roll-' ers 4242 and a centering ro ler 43, a top portion 44; and two upright side bars 4545 The centering roller 43 cooperates with two parallel guide strips 46 fastened to the locking plunger LP and having their ends beveled. When the locking plunger is moved to its unlocked position (to the right as shown) these guide strips 46 cooperate with the roller 43 and move contact shifter OS to the middle position and hold it thereuntil the locking plunger is returned to its locked position. The contact shifter CS is shifted to its extreme positions by normal and reverse selecting plungers" 47- 17 which are carried in brackets 48-48 fastenedto opposite bars of the lock rod LR. These selective plungers 4747 are arranged to be proected by the lock dogs 25 against the

roller

42 or 42 When the contact shifter CS is moved to its middle position, the contact carrier 29 is likewise moved to its middle position,'but

on account of the space between arm 36 and shifted to the corresponding extreme posi-.

tion.

The detector locking mechanism embody--- ing my invention comprises a lock bolt 50 supported and guided for up and down movement in a suitable support, indicated art of the frame of the switch machine. his look bolt '50, when down, lies in the path of movement. of the lock dog 25, and prevents unlocking movement of the lock plunger LP, the parts being disposed so that the lock' dog 25 strikes the bolt 50 diagrammatically as a frame piece 51,'which before the 'lock'rod LR is unlocked. The. belt is provided with an. enlarged head 52. An armature; 53, pivotally supporte on a pin 54 and arranged to be attracted by a lock releasing'electromagnet 5 5, has its end engaged under-said head, 52, so that the bolt asthe switch machine locks up.'

manner.

50 is raised when said electromagnet 55 is energized. The lock bolt 50 may also be raised by a cutout plunger 56 which has a notch 57 near its lower end forming a shoulder adapted to engage under the enlarged head 52 of said bolt. The plunger 56 extends upwardly through a suitable supporting panel 58 to a point readily accessible, and is provided with a knob 59 for facilitating its manual movement. This knob 59 is provided with a key-like projection 60 fitting in a similar shaped notch in the panel 58, so that by lifting and partly turning the knob 59, the plunger 56 may be retained in its upper position. This plunger 56 carries an insulated contact disk 61 arranged to electrically connect two resilient contact fingers 62 fastened to an insulated block 63. A spring 64: between the disk 61 and the block 63 presses the plunger 56 downward.

Near the lower end of the cutout lunger 56 is a detent angle lever 65 pivota ly supported on a fixed pin 66 and having one vertically disposed arm arranged to catch under the plunger 56 when it is raised, thereby preventing its downward return movement. This upright arm is connected to one end of a tension spring 67 which is anchored at its other end in any suitable Below the other horizontally disposed arm of the detent lever 65 is a releasing plunger 68 guided in the frame piece 51 and having its lower end beveled and arranged to be engaged and lifted by the upper edge of the lock dog 25. The releasing plunger 68 is provided with an enlarged head 69 limiting its downward movement. A compression spring 70 is interposed be tween the head 69 and the horizontal arm of the detent lever 65, the ends of said spring being guided by suitable pins. The spring 7 0 is made with practically no initial tension when extended (as shown) but when compressed is stronger than the spring 67 to permit the operation hereinafter described.

For the purpose of more fully explaining the operation of my improved detector looking mechanism, I have illustrated diagrammatically in Fig. 2 a layout for one switch, comprising a stretch of track A and a turnout D with its controlling switch, the lever L and its associated devices in a tower (these parts being inclosed in a dotted rectangle 71), and some of the principal parts of the switch machine more fully shown in Fig. 1 used for operating the switch, together with the electrical connections. The track railsof the main track A and turnout D are provided with insulated joints 72 and are bonded in the usual manner, as shown, so as to provide a detector track circult, 1ncluding battery 73 and a track relay 74-having a contact finger or armature 75. The lever L is connected to a rod 76 which operates contact blocks 77 to bridge pairs of contact springs, as 78. The indication latch for the lever is designated 79, the indication magnet I, the safety magnet S, the indication selector IS, the polarized relay PR, and the main battery B, these parts being of well known construction commonly employed in the dynamic indication type of electric interlocking system illustrated.

The electromagnet 55 of the electric lock is connected so as to be picked up by the drop in potential across the field 1 of the motor M when it is operating, provided the track relay 74: is energized, this connection comprising wire 80, front contact of armature 75, wire 81, field 41, and wire 82. The contact springs 62 and the contact disk 61 of the cutout plunger 56 are included in the common wire C between the motor and the main battery B. In other respects the electrical connections illustrated are common to this type of system and need not be specifically described.

Operation: Referring to Figs. 1 and 2, the parts of the switch machine and lever L have for convenience been shown in the reverse position, and when the lever is moved to the normal indication position, with the view of returning the switch. points to normal, current is supplied from the main battery B over the normal control wire N through the contacts on the operating circuit controller 0, along a path which can be readily traced, through the motor M and back along the common wire 0 to the main battery. The drop in potential across the motor field 1 energizes the electromagnet 55 and raises the lock bolt 50.

The detector locking mechanism is thus released, and the switch machine now operates in the usual way to throw the switch points. Referring to Fig. 1 and briefly reviewing this operation, the motor rotates the main gear 5 clockwise, and as the driving pin 15 is moved in its circular path 18, the lower roller 17 engages one edge of the cam slot 22 and shifts the locking plunger LP (to the right as shown) to its unlocked position, thereby unlocking the throw bar T and the lock rod LR. During this movement the releasing plunger 68 is raised by the lock dog 25, but since the detent lever 65 cannot move (the cutout plunger 56 being down), the spring 70 is merely compressed without producing any movement of the parts. The guide strips 46 put the contact shifter CS to the middle position. This in turn places the contact carrier 29 in its middle position, bridging both sets of contact fingers 26 associated therewith, so that a circuit through either the normal or reverse pole changer coils 34.- or 35 may be set up, thereby permittingthe switch machine to be reversed in mid-stroke, if desired, in the manner characteristic of this system and fully explained in my prior patent above switch points are unlocked.

. ing of the cutout plunger mentioned. The switch points -being unlocked, the upper roller 16 en ages the jaw 19 of the throw bar T and shi ts said throw bar and the switch points to their other extreme position. The lower roller 17 now engages the other edge of the cam slot 22 and returns the locking plunger LP to its locked position. The lock dog 25 enga es the selecting plunger 47 the lock rod R having been shifted. to its other position by the movement of the switch points, and pro jects this selecting plunger against the roller 42 thereby shifting the contact shifter OS to its normal extreme position. This movement changes the operating circuit, controller, breaks the normal operating circuit and sets u the normal indication circuit. The motor RI acts as a generator in the manner characteristic of dynamic indication systems, and icks up the indication magnet I, releasing t e lever L and signifying to the operator that the movement of the switch desired has been properly accomplished.

Referring now to the features of my looking mechanism, if a train should be present upon the detector track circuit ,at thetime' the lever L is moved with the view of throwing the switch points, the track relay 74 will be deenergized and the circuit through the releasing electromagnet broken at the contact finger 75. The lock bolt 50, therefore, will remain in its lower position and will be struck by the lock do 25 before the This stops furthe switch machine, the clutch 10 lipping, or perhaps a fuse being blown. In any event, the switch points are not unlocked or moved. Thus, the switch cannot be thrown under a train, or after the train has come within the limits of the detector track circuit.

It may happen that just after the lever is operated and the switch machine has unlocked and commenced its cycle of operation, a train may enter the detector track circuit. Under these circumstances, it is better for the switch machine to complete its operation and have the switch points in one position or the other andfully. locked, than to have the points in mid-stroke or unlocked. This is taken care of in my improved de-' tector locking mechanism, since deie'nergiza-, tion of the electromagnet 55 and dropping ther operation of i of the lock bolt 50 after the machine has become unlocked, merely lets the lock bolt 50 down on top of the lock dog 25 and does not prevent the switch machine completing its cycle 'of operation.

en it is desired to operate the switch machine by hand for the purpose of inspection or repair, the mainta ner may raise the lock bolt'50 and unlock the machme bylift- 56, the shoulder at the edge of the notch 57 in said cutout plunger coiiperating with the enlarged 'head 52 be applied to the machine.

of the lock bolt. After the cutout plunger 56 is raised, the knob 59 is turned slightly, bringing the projection 60 out of alinement with its slot and up against a suitable stop (not shown), the parts being arranged so that this movement does not disengage the cutout, plunger 56 from the lock bolt 50. This holds the cutout plunger 56 in its raised position against the tension of the spring 64.. The lifting of the plunger 56 also breaks the main common of the switch machine at the contact disk 61, so that current cannot This is important, because if the maintainer should crank the machine clear over with power on, he might be injured by the automatic reversing action characteristic of this type of machine. In this way the cutout plunger 56 constitutes a safety device for protecting the maintainer, as well as a means for lifting the locking bolt 50 and permitting the machin to be cranked over.

When the machine has been unlocked by hand in the manner just described, and is cranked over, the lock dog 25 engages the beveled end of the plunger 68 and raises it. This compresses spring 70, and the cutout plunger 56 being now raised, the detent lever is swung to engage underneath said outout plunger. So long as the machine is unlocked, the plunger 68 is held u by lock dog 25, and the cutout plunger 56 1s retained in its upper position. When the machine is locked up, however, the lock dog 25 clears the plunger 68, and permits it to return to its lower position, relaxing the tension of spring 70 and permitting spring 67 to swing the detent lever 65 back to the normal position shown. check upon the maintainer and assures that he is not likely to leave the switch machine in mid-stroke, or unlocked after he has cranked it. To illustrate, unless the maintainer cranks the machine clear over to either the normal or reverse. position and far enough to lock up, he cannot return the cut out plunger 56 and put; the machine back under the control of the lever. Therefore, the maintainer could not leave the switch machine in mid-stroke or unlocked without greatly inconveniencing the operator, who in all probabilit would see to it that the maintainer wou d not likely repeat such carelessness. v

Sometimes a switch machine for some reason or another gets out of order and cannot be operated from the lever. In such case it is necessary to crank the machi e by hand in order to change the switch for trains. The'present practice is to lift the brushes on the defective machine, and then upon receiving a signal from the o erator, crank the machine over by hand. t sometimes happens that the brushes are not properly secured and the jar of the train causes them to drop back against the commutator,

thereby applying power to the machine and erhaps throwing it under the passing train.

his condition is also taken care of by my improved locking arrangement. Before the switch machine can be cranked, the cutout plunger 56 must be raised to release the lock bolt 50, and when this is done power is cut off from the machine, as previously explained. It will be noted that the cutout plunger 56 is positively held in its upper position in such a way that it is not at all likely to be jarred down by a passing train. Furthermore, said plunger 56 is positively held up by the detent lever '65 until the machine is locked up; and when this is so, the lock bolt 50 is under the control of the detector track circuit and is capable of acting to prevent operation of the switch machine if a train occupies this track circuit. In other words, according to my invention, power must be cut off from the machine before it can be cranked by hand, and this power cannot be reapplied until the machine is thrown fully over and locked up and the detector locking mechanism is in condition, to prevent the switch machine from being thrown if the detector track circuit should be occupied.

In the modification shown in Fig. 3, there is provided another arrangement of circuits for energizing the electromagnet 55 subject to the control of the detector track circuit, by power derived from the main battery B at the tower. In this arrangement the electromagnet 55 is provided with two windings 85 and 86, the winding 85 being of comparatively high resistance, and the winding 86 of low resistance. The high resistance winding 85 is connected in the main common C in series with the contact 75 of the track relay 7 4, this connection being as follows: commencing at the main common C, contact springs 62, contact disk 61, wires 87 and 88, winding 85, wire 89, armature 75,

wires

90 and 91, and thence to the motor and pole changer coils in the usual way. Thus, when current is supplied to the switch machine, the high resistance winding 85 is energized, providing the detector track circuit is unoccupied. This raises the lock bolt 50 and operates the locking mechanism in the same manner as previously described. The circuit for the low resistance winding 86 is also included in the common return connection through normally open contacts 92-93, this partial circuit being as follows: commencing at wire 87, wire 94, winding 86, wire 95, contacts 92-93 closed, and

wires

96 and 91 to the switch machine. The contacts 92 and 93are shown as insulated from each other in any suitable way and fastened to the frame piece 51, contact 92 being a resilient strip which projects out above an insulated pin 97 in the lock bolt 50, the arrangement being such that when said lock bolt is raised, contact 92 is moved into en gagement with contact 93, thereby establishing the energizing circuit for the low resistance winding 86. When the contacts 9293 close, the high resistance winding 85 is shunted by the much lower resistance path through winding 86, and the net resistance in the common connection is therefore very low so as not to interfere with the proper operation and indication of the machine. The electromagnet 55 in this arrangement is preferably made slow-acting in some of the ways well known in the art, as for example, by surrounding the'cores with copper tubes, so that after operating current has ceased to flow, the'lock bolt 50 will be momentarily held up to keep the contacts 9293 closed while the indication current is building up, and thereby maintain a low resistance path for said indication current.

In this modified arrangement shown in Fig. 3, if the detector track circuit is not occupied, the winding 85 is energized when power is applied to the switch machine, the lock bolt 50 picked up, and the low resistance winding 86 cut in to hold up said lock bolt as long as current is applied. If a train should enter the detector track circuit before the switch machine completes its cycle of operation, the lock bolt 50 will be held u by the current in the winding 86 and also by the lock dog 25. If, however, a train is on the detector track circuit when the lever is operated, the winding 85 cannot pick up the lock bolt 50, because its circuit is broken at the armature of the track relay 74:, so that the switch machine cannot be operated.

In the modification shown in Fig. 4, the electromagnet 55 is provided with two oppositel wound windings 98-99 of the same num er of turns, thereby constituting in effect a differential relay. The windings 98 and 99 are connected across the control wires. and main common through the armature 7 5 of the track relay 74, high resistances 100 being connected in series with said windings. Assuming the switch machine to be in the reverse position, corresponding to that shown in Figs. 1 and 2, the normal control wire (marked N) is connected to common through the indication magnet at the tower and the reverse pole changer coils 34; at the switch machine. The reverse control wire R is connected to the main battery B at the tower. Current then flows from the reverse control wire through resistance 100 and winding 99, wire 101, the track relay armature 75, wire 102, through contact dlsk 61 and along main common back to the battery, this energizing the winding 99. The winding 98, however, has practically no current flowing in it, because it is short-circulted, its terminals being conconnected in a circuit including t e ,and since these windings are wound equal and opposite, the lock bolt 50 is released. It will be noted that one winding of the electromagnet is normally energized and the lock bolt 50 is normally raised, as distinctive from the other bolt in its lower position. The modification of Fig. 4, therefore, has one disadvantage in that it is always consuming current. In this connection it shouldbe understood that the windings are made of high resistance, together with external resistances 100 inseries therewith, so as to limit the current and also prevent interference with the proper operation of the system. For ex-v ample, Ifind it preferable to employ windings and external resistances 100 such as to give a total resistance between control wiresof some 8000 ohms.

In some cases a suitable source of energy for operating electromagnet 55 is available at the switch machine, either from some local battery used for other purposes, or from power bus lines running through the plant. In such cases'it is, of course, unnecessary to employ the schemes illustrated in Figs. 1, 2 and 3 for energizing the electromagnet 55 from the main battery at the tower, the electromagnet 55 'bein merely source of current available, as a battery 105, and the armature 75 of the track relay 74, in the manner shown in Fig. 5. v I

From the foregoing it will be evident that I have devised a detector locking arrangement which will act directly-on the switch operating mechanism, rather than indirectly through a lock on the controlling lever.

Also, the detector locking mechanism will not cause the switch oints to stand in midstroke or unlocked if the train should enter the detector track circuit while the switch machine is operating; it protects the maintamer from injury 1f heattempts to crank the switch machine by hand, since he is compelled to cut off the move the machine; it make'sit unlikely that 'the maintainer will leave the switch -ma-: chine partly cranked. over, he cannot since otherwise arrangements in which the electromagnet 55 is deenergized and the lock power before he canv ut the machine back 'under :the

control ,of the lever and wQiild'interfere-with -s'witch,;the same 'a'rrangement the operation of the plant; and it also prevents the machine belng operated by power ,to throw the switch points under a train, where the machine has been cranked over by hand out of correspondence with its lever, since power cannot be applied unless the locking mechanism is capable of acting to prevent such improper operation. These features ef my invention provide additional protection over that provided by the electric locks on the controlling levers now com monly employed, because the locking action of a train takes effect directly on the operating parts of the switch machine, regardless of the position of the lever, and also because the manually operable device for cutting off power from the machine to permit cranking it over by hand is coerdinated with the track circuit controlled locking mechanism in such a way that power cannot be applied to the machine unless the detector locking mechanism is capable of acting. To illustrate this distinction, consider a system with electric lever locks, and assume that the switch machine is cranked over byhand while a train is on the detector track circuit. The lever is locked in its existing position, and if the machine should be cranked fully over with power on, it would be automatically reversed by the power to its former position, on account of the automatic reversing action char acteristic of this type of switch machine. To prevent this automatic reversal, it is the usual practice to lift the brushes of the motor, or open some suitable cutout circult controller, the power in either case being cut off from the switch machine. It may happen, however, that the brushes are not properly secured and may be arred down by the. vibration of the passing train, or the operator may carelessly close his cutout circuit controller after having cranked the machine over, and in either case, power is re-applied to the switch machine and it may happen at the right time to cause be thrown under the train. This dangerous possibility is obviated by my invention for the reasons previously explained. It being impossible to put power back on the switch machine unless it-is in condition such that the lock bolt 50 can prevent the automatic reversing operation if there should be a tram present.

. Obviously, various adaptations and mod1- fications of my invention as herein shown and described may be made without deviating from its principles and mode of operation. vMy improved detector locking mechanism jmay be applied to other types of power operated interlockingsystems, whether operated by alternating current or direct current; and'whi-lejljhave illustrated'my inven ion 11in, itssimplestform. applied to one;

' be adaptthe switch points toed and applied to any combination or arrangement of interlocking. I desire to have it understood, therefore, that the particular embodiments of my invention shown and described are merely illustrative, and do not exhaust the various forms which may be used in practice.

That I claim as new and desire to secure by Letters Patent of the United States, is

1. In an interlocking system, the combination with a switch machine and detector track circuit, of a normally denergized electrically operable lock acting directly on the operating parts of the switch machine and controlled by said track circuit, said lock being energized when power is applied to the switch machine, provided said track circuit is not occupied.

2. In an interlocking system, the combination with a switch machine and detector track circuit, of an electric lock for the switch'machine controlled by said track circuit and capable of preventing unlocking of the switch machine without interfering with its operation after being unlocked, whereby the switch machine may complete its cycle of operation after having once unlocked in spite of the entrance of a train into said track circuit.

3. In an interlocking system, the combination with a switch machine and detector track circuit, of a lock normally acting to prevent initial operation of said switch machine, and means controlled by said track circuit for disengaging said lock when power is applied to the switch machine and said track circuit is not'occupied.

4. In an interlocking system, the combination with a detector track circuit and an associated switch machine controlled from a source of current at a tower, of an electrically operable lock for the switch machine, and means controlled by said track circuit for causing energization of said lock from said source of current.

5. In an interlocking system, in combination, a power operated switch machine, a detector track circuit, and means controlled by said track circuit for mechanically preventing initial unlocking movement of the switch machine while said track circuitis occupied but permitting'said mechanism to complete its cycle of operation after once unlocked.

6. In an interlocking system, in combination, a power operated switch machine having a locking plunger, and a track circuit controlled electrically operable lock for preventing unlocking movenient of said plunger.

7 In an interlocking system, in combination, a power operated switch machine having a locking lunger, a normally deenergized electrical y operable lock for preventing unlocking movement of said plunger, and means adapted to be controlled from the track circuit for controlling the energization of said lock.

8. In an interlocking system, in combination, a power operated switch machine, track circuit conrolled locking mechanism for preventing initial operation of said machine, and manually operable means for releasing said locking mechanism independently of its control by the track circuit to permit operation of the switch machine by hand.

9. In an interlocking system, in combination, a power operated switch machine, track circuit controlled locking mechanism for preventing initial operation of said switch machine, a manually operable device for cutting off the supply of power to the switch machine and means for preventing restoration of said device to normal while the switch machine is unlocked.

10. In an interlocking system, in combination, an electrically operated switch machine, a power circuit therefor, a manually operable circuit controller for breaking said power circuit, and means governed by the movement of the switch machine for preventing closure of said circuit controller while the machine is unlocked.

11. In an interlocking system, in combination, an electrically operated switch machine, a power circuit therefor, a manually operable circuit controller biased to its closed position for breaking said power circuit, and means for maintaining said circuit controller open while the switch machine is operating.

12. In an interlocking system, in combination, a power operated switch machine, a track circuit controlled lock therefor, manually operable means for releasing said lock and for simultaneously cutting oil the supply of power to said machine, and means preventing restoration of said means to normal while the switch machine is partly operated.

13. In an interlocking system, in combination, a power operated switch machine, a detector track circuit, a lock controlled by said track circuit for preventing initial operation of said machine, a manually operable device for releasing the lock to permit operation of the machine by hand, said device when operated acting to cut oil the supply of power to the machine, and means preventing restoration of said device to normal while the switch machine is unlocked.

14. In an interlocking system, in combination, a power operated switch machine provided with a locking plunger, a detector track circuit, a normally denergizedelectrically controlled lock for preventing unlocking movement of said plunger, a manually operable device for releasing said lock to permit operation of the machine by hand, said device also acting to cut off the supply of power to the machine, and means governed by said plunger for preventing restoration of said devlce to normal while the switch machine is unlocked.

15. In an interlocking system, a power operated switch machine, means for dis-connecting said switch machine from its operating source of power to permit operation thereof by hand, track circuit controlled locking mechanism acting directly on the operating parts of said machine, and means preventing power being applied to the machine until said locking mechanism is in condition to act.

16. In an interlocking system, a switch machine operated by an electric motor, a detector track circuit, and a normally deenergized lock for said machine controlled by said track'circuit and energized by the drop of potential across the motor field.

17. In an interlocking system, a switch machineoperated by current from a main source at the tower, a track circuit controlled electric lock for said machine adapted to be energized b current from said main source, and manually operable means for releasing said lock independent of its control by said track circuit.

18. In an interlocking system, a switch machine and an electric lock therefor, a track circuit, and separate manual and automatic means for controlling said lock, both acting to prevent the switch machine being operated b power while said track circuit is occupied 19. In an. interlocking system, the combination with a power operated mechanism for moving the points of a switch, a track circuit, locking means controlled by said track circuit and normally acting upon said mechanism while it is at rest to prevent operation thereof, and automatic means operable to release said locking means provided the track circuit is'not occupied.

20. In an interlocking system, a power operated switch and lock mechanism, control means including a lever for governing the operation of said mechanism from a distant point, a track circuit, locking means normally acting to hold the parts of said mechanism from operating, and means controlled by said track circuit for releasing said lockin means when said lever is shifted, provi ed the track circuit is not occupied;

21. In an interlocking system, a power operated switch actuating mechanism having a lockin plunger, normally acting locking means or preventing unlocking movement of said plunger, and track circuit controlled means for releasing said locking means.

22. In an interlocking system, a power point while the operated switch actuating mechanism hav ing a locking plunger, a normally deenergized electrically operable lock normally acting to prevent unlocking movement of said plunger, a track circuit, a lever controlling said mechanism, and means coneration of said mechanism from a distant point, of normally acting track circuit controlled locking means for preventing operation of said mechanism from said distant track circuit is occupied.

24;. In an interlocking system, a power operated switch actuating mechanism, a normally acting lock for preventing operation of said mechanism,-a source of current at a distant point for controlling said mechanism, a track circuit, and means including a double wound electro-magnet energized from said source for releasing said lock providedthe track circuit is not occupied.

25. An interlocking system comprising a power operated switch and lock mechanism, a track circuit, and means acting while the track circuit is occupied for cooperating with said mechanism to hold it in its locked condition.

26. In an interlocking system comprising a power operated switch machine including driving and driven elements connected by a yieldable connection, and track circuit controlled means acting to hold thedriven element against movement while the track circuit is occupied.

27. An interlocking system for railroads comprising a switch machine haying a lockingplunger, a motor and drivlng connections including a friction clutch for actuats ing said plunger, and track circuit controlled means acting to hold the locking plunger in its locked position when the track circuit is occupied.

28. In a power interlocking system for railroads, a switch machine, a track circult, locking means normally acting while the switch machine is at rest to prevent operation thereof, and automatic means operable to release the locking means provided the track circuit is not occupied, said locking means being ineffective to prevent the switch machine completing its cycle of operation after once started.

29. In an interlocking system, the combination with a detector track circuit and a power operated switch machine, of a normally deenergized electric lock for preventing operation of the switch machine, and means for releasin said look if the track circuit is not occupied, said lock permitting the switch machine to complete its cycle of operation after it has once started.

30. In an interlocking system, a detector track circuit, an electrically operable switch machine, a source of current and control means at a distant point for governing the operation of said switch machine, a normally deenergized electric lock for preventing operation of said machine, said lock permitting the machine to complete its operation after once started, and means controlled by the track circuit for causing energization of the lock.

31. A power interlocking system for railroads comprising a track circuit, a switch machine having a locking plunger, and locking means governed by the track circuit for preventing unlocking movement of said plunger, said means being ineffective while the plunger is unlocked.

32. A power operated interlocking system for railroads comprising a track circuit, a switch machine, a normally denergized lock for preventing operation of said switch machine, said lock permitting the switch machine to complete its cycle of operation after once started, and means for automatically energizing said lock provided the track circuit is not occupied.

33. A power operated interlocking system for railroads comprising a switch machine, a source of current and control means at a distant point for governing the operation of said machine, a detector track circuit, electrically operable locking means adapted to prevent initial operation of the switch ma-' chine but permitting it to complete a cycle of operation once started, and means for releasing said locking means by current supplied from said source when the track circuit is not occupied.

34. In an interlocking system, the combination with a power operated switch machine, of automatic locking means for preventing operation thereof, and manually operable means for independently releasing said locking means to permit actuation of the switch machine by hand.

35. A power operated interlocking system comprising a switch machine, normally acting locking means preventing operation of said machine, and a manually operable device for independently releasing said locking means.

36. A power operated interlocking system comprising a switch machine, normally active means preventing operation of said machine, and manually operable means at the switch for rendering said first mentioned means inactive.

37. A power operated interlocking system comprising a switch machine, track circuit controlled locking means normally acting to prevent operation of said machine, and manually operable means for releasing said locking means and for simultaneously rendering said machine incapable of being operated by power.

38. power operated interlocking system comprising an electrically operable switch machine, track circuit controlled means normally actingto prevent operation of said machine, a manually operable device adapted to release said means and simultaneously interrupt the supply of current to the switch machine.

39. Detector locking mechanism for switch machines having a locking plunger and a lock dog fixed thereto, comprising a lock bolt arranged to engage the lock dog and prevent unlocking movement of said plunger.

40. A detector locking mechanism for switch machines of the type in which alocking plunger is shifted to its unlocking position at the beginning of the cycle of operation of the switch machine and to its locking position at the end of said cycle, a locking bolt adapted to prevent the initial unlocking movement of said plunger and thereby prevent operation of the switch machine, said locking bolt permitting final locking movement of said plunger, and electromagnetic means for actuating said lock bolt.

41. The combination with a switch operating mechanism, of a lock bolt for preventing operation of said mechanism, and automatic electromagnetic means and manually controlled means each operable to release said lock bolt.

42. In an interlocking system, the combination with a power operated switch machine controlled from a source of current at a distant point, of means for preventing operation of said mechanism adapted to be actuated manually or electrically, said means being automatically operated by current from said source at the distant point.

43. A power interlocking system comprising a switch operating mechanism, a control circuit therefor, manually operable means for interrupting said circuit, means acting while said mechanism is in an intermediate point in its cycle of operation for preventing actuation of the manually-operable means to the position in which said circuit is closed, and track circuit controlled means effective only after said mechanism has completed a cycle of operation for preventing its further operation. a

44. A power interlocking system comprising a switch operating mechanism, track circuit controlled means effective when the mechanism is at rest at the completion of a cycle'of operation for preventing another cycle of operation of said mechanism, and manually operable means for rendering said means ineffective and for simultaneously preventing operation of the mechanism by power.

. applied to the mechanism 45. A power operating switch machine having a locking plunger, a normally inactive manually operable device for preventing operation of the machine by power, and means whereby said device cannot be restored to normal while the locking plunger is in its unlocked position.

46. A power interlocking system comprising a switch machine, track circuit controlled locking means for preventing operation-of said machine while at rest but permitting completion of a cycle of operation once started, manually operable means for releasing said locking means to permit operation of the switch machine by hand while the track circuit is occupied, said releasing means when actuated preventing application of power to the switch machine, and means whereby said releasing means cannot be restored to normal until the switch has completed its cycle of operation.

47. In a traflic controlling system for railroads, a switch operating mechanism, track circuit controlled means effective to prevent operation of said mechanism in the fully 0perated condition thereof, manually operable means for cutting off the supply of power to the mechanism to permit operation thereof by hand, and means preventing restoration of said manually operable means to supply power to the mechanism when it is only partly operated, whereby power can not be after hand operation thereof unless the track circuit controlling means is capable of acting.

48. In an interlocking system for railroads, a switch operating mechanism, track circuit controlled means normally acting to prevent operation of the mechanism from means preventing restoration either of its. fully operated positions, said means being controllable from a distant point to allow operation of the mechanism When the track circuit is not occupied, a manually operable device adapted to render said means ineffective independent of the track circuit control thereof, and thereby permit operation of the mechanism by hand, said device when actuated preventing application of power to the mechanism, and means preventing restoration of said device to normal when the mechanism is only partly operated, whereby power can not be applied to the mechanism after hand operation thereof unless the track circuit controlled means is capable of acting.

49. In an interlocking system, switch operating mechanism having a cycle of operation between two extreme positions, manually operable means located at the mechanism and adapted to be actuated to prevent application of power to the mechanism, and means preventing restoration of the manually controlled means to supply power to the mechanism unless it is one of its extreme positions.

50. In an interlocking system, a track switch, electrically controlled mechanism for actuating and locking the switch, a lever and control circuits for causing the mechanism to be operated by power to a position correspending with the position of the lever, a

manually operable device for interrupting the control circuits and thereby prevent op eration of the mechanism by power, and of said device to normal unless the switch is in an extreme position and locked.

J WINTHROP K. HOWE.