US1561717A - Automatic crossing gate - Google Patents

Description

W. HARDER AUTOMATIC CROSSING GATE Filed June 16. 1924 3 Sheets-Sheet 1 Nov. 17, 1925 w. HARDER AUTOMATIC caossms GATE Filed June 16, 1924 3 Sheets-Sheet 2 Nov. 17', 1925- w. HARDE-:R

AUTOMATIC CROSSING GATE Filed June 16, 1924 3 Sheets-Sheet a -lillllllllF-m-yw/05 f @-95 l 42 QZ Patented Nov. 17, 1925.

assign WILLIAIYI HARDER,

OF REMSEN, IOWA.

AUTOMATIC CROSSING GATE.

Application filed .Tune 1G,

To all whom t may con-cern:

Be it known that I, WILLIAM Hannan, a citizen of the United States, and a resident of Remsen, in the county ot' Plymouth and State of Iowa, have invented certain new and useful Improvements in Automatic Crossing Gates, ot' which the 'following is a specification.

My invention relates to crossing gates for railway crossings, particularly of the type that are automatically actuated by the passing et a train, and it is my object to provide such a gate construction which is of simple, durable and inexpensive construction.

More particularly it is my object to provide a gate pivoted for movement in a verti cal plane, a motor operatively connected with the gate and adapted to move it from open to closed position, and vice versa, and controlling means for starting and stopping the motor, including an electric circuit, which electric circuit includes a section of the rails of the track and is thus completed when a train contacts with the section or comes into the block.

Another object is to provide a balanced gate and a relatively small spring-driven motor, the gate being such that continued rotation of the motor in the same direction during successive periods of operation will respectively lower and raise the gate. By using the balanced gate, very little power is required from the motor, and a spring motor may thus be utilized which is adapted, from the winding, to store enough energy to actuate the gate during the period of twenty-four or forty-eight hours.

lvlore speciiically it is my object to provide in the controlling mechanism for the motor means tor starting the motor when the train enters and leaves t-he block, respectively, and automatic means forming part of the motor for checking the rotation thereof at the end of a predetermined period cf such rotation.

Utilizing the structure generally set Jforth in the preceding objects, it is my purpose to provide an automatic crossing gate actuated by a spring motor ot such construction that it will not readily get out of order, and controlled by an electric controlling system, utilizing the block system which has proven very satisfactory in controlling railway signals.

Another object is to provide a resilient 1924. serial No. 720,23?.

connection between the motor and the gate whereby the sudden checking of the gate by an obstruction interposed between its path or' movement will not suddenly check the operation oi the motor so as to injure the same. Such spring connect-ion is designed also to serve the purpose of such resilient connection, allowing the motor to start while the inertia. ot' the gate continues to hold it back, and then to accelerate the movement of the gate after it has started. f

A further object is to provide a signal light carried by the gate and controlled by movement of the gate to closed position.

lith these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts oic my device, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Fig. l is a perspective view of my improved crossing gate, the grease casing at the ends of the lever arm being omitted.

Fig. 2 is an elevation of a portion of the motor showing the driven shaft and the crank arm thereon, together with a portion of the lever arm and connecting link.

Fig. 3 is a detail sectional view through the light switch.

Fig. 4 is a plan view of the motor, the house therefor being shown in section.

Fig. 5 is a vertical sectional view through the housing, showing the motor and source of electrical energy in elevation.

Fig. 6 is a diagrammatic view of the entire apparatus.

Fig. 7 is a detail view illustrating the mounting of the gate, parts thereof eing shown in section.

Fig. 8 is a detail sectional view through the end of the lever arm and the resilient connection between the arm and the gate, and

Fig. 9 is an enlarged detail sectional view through the governor shaft of the-motor, illustrating one ot the brake arms.

In Fig. 1 I have shown at 10 the rails of the ordinary railway track, and at ll a highway crossing the track. The gate is supported by the posts, 12, which are suitably mounted by the side oit the rails, 10, and adjacent the highway, ll, so that the gate, when in lowered position, will, extend entirely across the road. The gate l `have shown merely tor the purpose ot illustration as a long beam, 13, in which is mounted near one end thereotl the roller bearing, 111s, on which the gate is pivoted. 'ilhe gate is mounted between the posts, 12, by ineens of the bolt or shaft, 15, which extends through the posts and through the bearing, 1e. 'lhe roller bearing, 111, may be ot the ordinary construction, as used tor the axles ot automotive vehicles.

It. will be seen that the tspite is thus mountAn ed so as to rotate very freely on its axis. I provide a Counter-weight 'tor the lower end oit the gate, which n'iay be ot any suitable construction, but the one i have shown comprises the bars, 16, :lined to the lower end oi the beam, 13, and on which is slidably mounted the weight, 17. .i set screw, 18, allows adjustment ot' the uf'eip'ht, 17, relative to the axis ot the nnte in order to balance the gate.

l provide a spring motor to? actuatingthe gate which is preterably mounted in a housing, 19, situated near the tracl: and which is Closed by a door, 20 and loelred by a suitable looking means, 21. Vthe motor is thus protected from the weather and troni intruders.

The motor is mounted on a sholt, within the house, 19, and coniprises a bese, 23, to which `is fined the side upright traine members, 211. rlhe power is derived troni a spring, 25, mounted on a shatt, 26, and is transmitted to the driven shaft, 2i', through the` medium ot the large gear, 23, and the pinion, 29. The gear, 28, is loosely ounted on the shatt, 26, and is connected with the spring, 25, through the niodiznn ot the ratchet, 30, and pawl, 31.

The structure just described is ot the ordinary .construction usually tound in clocks and other derives using; spring' driven motors,

In order to wind the spring' l provide the pinion, 32, in mesh with the winding gear, 33. The pinion, 32, is mounted on a stub shaft, 34, fined to the trame, and has the pins, 35. A. eranlt, 36, is provided havingr the soelet, 37.. and the slots 3a, therein to receive the pms. 3:?. rihe '.ket,

37, is adapted to lit over the end et the shatt, 34. In winding" the rear is turned, as indicated by the arrow, 3S). The gear, 33, may be made larger than the gear, in order to increase the l-verage exerted upon the spring' by the winding' crenlv. rifhe driven shat't, Q7, extends through the bach' of the house, 19, and on its end is mounted the crank arm, 110.

In order to transmit the power 'trom the motor to the gate l provide the tollowing means. llPivoted to a suitable post, 4:1., n'iounted between the house.. 19, and the gate a lever arin, 12, which extends behind and momia the end ot the lever arm and ma;Y be filled with grease through the grease cup, 4&6. d. roller bearing' may be used to torni :i oonnection between the pin, Lte', and the lever L12. l. ivoted between the bars, 1%3 at l?, is the upwardly-entending: rod, l. ivoted by means of the pin or bolt, r9, to the end ot the lever arnnl. are the dovnwardlv entendingl rods, 50. It roller homing oonnection, 51, may be provided between the pin. 49.. and the arnii, 42. Fixed to the rods, 50, intern'iediate ot their length a cross plate, 5i?. having at its center an opening, 5ft. throiuigh which the upper end oi the rod, 43 is slidably mounted. lliiied to the rod, i3, near the lower ends ot the rods, 50, is a bar, having' the openings, 55, at its ends, througl'iwhich are s lably received the lower ends ot the rods, 50. .fi spring, 56, encireles the rod, 43, between the plate, and the bar, 54. and is conneete-il thereto as shown. lt will be seen that a resilient connection is thus provided between the end ot the lever, 112, and the rod, d8, whereby movement of the rod either toward or away troniA the lever `will be resisted by the spring, 5G.

it will be seen trom the foregoing description that as the arm, e0, rotate from the position shown in Fig. 2 to e position where it extends vertically downward that the lever arm, 42, will be drawn to the position shown in dotted lines in Fig. 1, and' the gate low ,red to the position shown in dotted lines in Fig. 1. When the arm, #110, rotates throiurh another 1800. the gate will be raised airain to the position shown in full lines. lt will thus be seen that in order to properly control the movement ot the nate it is necessary to control the rotation ot the shaft. 2i. through successive periods ot 1800 respec/tively;

l will now descri ne the means it'or eontrolling;` the motor. nnted on the traine, 2li, is the governor sha i 5i', having' the pin* ion, 58, which is connected through a train ot gears, 5), to the shatt, QT, so that rotation ot the shaft, will cause the slnitt, to revolve very rapidly in the direction indieated by the arrow, (it). The ordinzuv 'tan 1governor. ($1, is provided tm' eontrollinir the speed ot the shaftn F" @n th i f which is nru'inaliv he. b v the upwardly-L 'tondin arirmtnre, (iii, which is weld d or otherwise suitably secured to the lower end ot a pavvl, G5. ing arms, tlt, on the ends` oitI which are the r: rotation lip, h3, on the The pawl, (i5, has the laterally-often( v rip-turned ears, G7, through which is extended the rod, 68, serving to pivot the pawl, 65, and the armature, (ist, for swinging movement. In order to release the brake arm, 62, I provide the electro-magnets, 69, which are positioned under the end of the armature, (i4, so that when energized, the lip, 63, will be drawn downwardly ont oi the path of movement of the brake arm, 62.

For energizing the magnets, Gil. l provide the cells, 70, which are preferably storage batteries. It may be mentioned here that part of the circuit through which the cnrrent for energizing the magnets, 69. tiows, includes the rails, l0.

Referring, now, to the diagram sh wn in Fig. 6, the rails, l0, adjacent the highway are shown insulated from the remainder of the track, as at 7l. One side of the elect-romagnet, (S9, is connected to the storage hati tery, T0, through the wire, T2. From the other side oi" the magnet, (i9. the wire, 75, leads to one of the rails, l0. From the other rail, l0, the wire, F6, connects hack to the battery, T0.

It will thus be seen that when the wheels, 77, of a train Contact with the insulated portions of the rails a circuit will be established through the rails, l0, the wheels and axles, 77, the wire, 75, the magnet, 69, the wires, 72, the battery, and the wire 76, back to the other rail, l0. Tffhen the circuit is thus established the armature, G4, will be drawn downwardly so as to release the brake arm, 62, and to allow the motor to rotate until the shaft, 2T, has made half a revolution. I/Vhen this has been done, the motor is stopped by the meanswhich I will now describe.

I provide a second armature, T8, fixed to a stop arm, TS, which in turn is pivoted to the frame in a manner similar to the pawl, 65. On the end of the armature, 78, is the upwardly-extending hook, 80, normally positioned just below the end of a brake arm, 8l, Similar to the brake arm, (3Q. A rod, S2, limits the motion of the stop arm, 79, and thus properly positions the end of the armature, 78, under the brake arm, 8l. A weight, S3, adjustably mounted on the armature, 7S, by means ot' a screw, S4, received through a slot, 85, in the armature, tends to urge the end of the ari'nature downwardly away from the brake arm, 8l.

To stop the motor when the arm, l0. has made a half revolution I provide the niagnet. S6, mounted under the other end ot' the armature and adapted when energized to more the hook. S0, upwardly in the path ol movement of the brake arm, 81. I provide automatic means for controlling the magnet, Se. 'including a switch mounted on the shaft, 27, for rotation therewith. This switch may comprise a flexible arm of brass,

nected through the medium ot the wire. 7l.'

the knife. switch, one of the rails, 10.

It will now be seen that when the sha l't 2T, has rotated 180 from the position shown in Fig. 5, the arm, 8T, will contact with the brush, 90, as illustrated in dotted lines in Fig. 5, and a. circuit will be established through the brush, 90, the wire, 92, the. battery, 70, the wire, To. the rails, l0, thc wire. 75, the switch, 73, the wire, 74, the magnet. 86 and the frame, 2l. The arn'iature, T8, will then be drawn downwardly and the hook, S0, `will be moved into the path ot' the brake arm, Sl. In this connection it will and they wire. T5, lo

be noted that the brake, arm, 8l, is mounted on the shaft, 5T, so as to engage it fric tionally and yet to rotate thereon when sud denly stopped by the hook, 8o.

In order to so mount the arm. Si, it is provided with the collar, 93, which eneircles the shaft, 57, and is split and provided with the ears, 9st, which receive the adjusting screw, 95. 'Ihus the tension may be adjusted so that the inertia of the moving parts of the motor may he expended in ro tating the shaft. 5T, against the friction of the ring, 93, after the brake arm., 8l, has been arrested. The brake upon the shaft is suoli that it will quickly be brought to a stop for stopping the motor. The brake arm, G2, is similar in construction to the brake arm, 81.

In order to raise the grate the motor must again be set in motion. To do this the brake arm, 8l, is released by the hook, S0. This in turn is accomplished by breaking the circuit through the magnets, and it will be seen that when the train .leaves the block the circuit will be so broken and the motor will be allowed to operate, rotating the arm, 40, from its position extending downwardly to 'ard its upper position.

It may be mentioned here. that at many times the train may be delayed while in the block and it may bc desirable to raise the gates while the train remains there. For this purpose the switch, 72. is provided. and it will be seen that the opening of the circuit by releasing the switch, 75l, will cause the motor to operate for raising the gaie. There would be no necessity of again lowering the gate while the train remained in such position o1' before it proceeded on its journey, and therefore I have not provided means for so doing.

lli/Then the gate has been raised to its open position the motor is again stopped by the lip, G3, on the armature, (it. rlhe armature, 64, is provided with a weight4l` Se, similar to the weight,1 83i which tends to move the lip` tif-3, into the path of the brake arm, (ii/l.

lt will be seen that during;l the time tha, the gate is being; lowered and the motor bcing` controlled by the armature. F8T the ai-nurture, (ist, must be rendered inoperative in order that the rotation of the shait., will not be prevented by the lip, G52 't this purpose l in'ovide the dislY il?, mount on the shaitt, 2T, and so positioned in t path oi swinging niovement ot the pawl. ti, :is to maintain the armature, (tl, in the position to which it has been ureed by the mae:- net, (39. while the shattlq 2i. is making a complete revolution. rthus it will he seen that after the circuit through the magnet.y h has been lfn'olzen by the departure ot' the train trom the hloclr, the lip., G23, will be maintained out ot engagement with Jthe brake arm. GQ. in order to stop the uiiotor a notch, 98, is provided in the dish, 97A, which is so positioned relative to the other parts otl the motor that when the shaft, lil has assumed its upper position the pawl, (2in will drop into the notch and allow the parte to assume the position shown in lha'. whereby the lip (3?), will be moved into path oi" the brake arm. tor stfmpingl' motor.

Briefly it may be stated that; when the train leaves the block both n'iap'net-s will he cle-energized, one releasing; the governor mechanism of the motor and the other tendinni to ice-engage the governor niechanisnn but delayed in such action by the dish.` 9T; until the motor has rotated suliiciently to raise the rfijate.

I provide a signal lamp, 99, lived to the `gate near the center thereo'l: and which is preferably constructed similarly to an automobile headlight and provided with a red lens so as to warn motorists at night when the gate is being actuated. A switch is provided, mounted on the post, 1li-l, and contained within a suitable casing; 100. This switch may be ot any suitable construction so as to be actuated by the movement of the lever, i2, and 'for the purpose ot illustration l have shown in Fig. 3 a pivoted switch arm, 10i, actuated by the linie 1.02, which is connected to the leven 42, and adapted to close the circuit across the contacts, 103. and to energize the lamp. 99. through the medium ot the wires., 10st, and the batteryn 1,05.

My gate is comparatively simple in construction and may be made almost entirely of wood, The driving; motor need not be ot' very large proportions and is protected from the elements and from damage by animals or human being. ln the actual use of my invention it will be necessary that item/rt service operator he provided to wind the motors and keep them in ope a tive condition. as well as to charge the storage batteries.

ift may be stated here that ery cells might readily be used Yt'or the n'iagnetic controls, and that in place ot a amp a warning;- device similar to those in popular use on highways at dir'hcult curves and comprising, namely, a retrzuztivc and retiectiug prisinatic lens, might be employed. This would do away with the necessity ot' the storage battery 'or lighting the lamp.

'llhe service operator is to be provided with a suitable vehicle such as a hand car or inotor-driven car to travel on the rails, and each operator will he eiiabled thus to attend to :i arge number ot crossingsignals. lt will he his duty to wind them every twentydonr hours. The motors may be of such sine as to store power which will last Yfortyeipht hours so that it hy any chance the motors should be neglected tor a day they would ctn'itinne to operate.

lt will be seen that the apparatus is especially adapted tor use over long stretches et' railway where there is no available source of power and where storage batteries must be used. rllhe expense ot upkeep' ot storage batteries for actuating' an electric motor would be prohibitive, but the current required by my apparatus is e; :eedinp'ly small.

T he operator is to he provided with mechanism tor charging the batteries, which may be carried on the vehicle.

lt is tliouglit that the advantages ot providing an autoinatic gate, actuated by the approach and recession ot a train, are obvious. The ordinary autoi'nol'iile alarms now provided are ineli'ective tor the reason that the sound ot an automobile engine will excludev the sound ot a bell trom the ears of 'the motorist. ln order to eliminate the tendency o'lt the motorist to try and beat the train to the crossing an actual barrier must be interposed in his path.

Some changes may be .made in the construction and arrangrrelnent ot the parts of my invention without departing trom the real spirit and purpose ot :my invention. and it is my intention to cover by my claims any modified terms ot' structure or use of mechanical equivalents which may be rea-- sonahly included within their scope.

l claim as my invention:

l. ln anautoinatic crossing` gate. a balanced gate pivoted 'tor movement 'in a vertical plane a pair oi rails insulated trom the remaining rails in a railway track, a relatively small spring motor having' a driven shaftt, a crank arm thereon, operative means connecting' the crank arm to the grate so as to move it from open to closed position and from closed to open position hy rotation of the arm through periods ot 1800 respectively, means for locking the motor against movement when the gate is in open position, meansl actuated by the establishing of a lircuit across the rails tor releas ng the locking means, second moans tor again locking the motor when the arm has rotated through 180, and second means for releasing the motor, said second releasing means being actuated by the breaking oi the circuit across the rails.

in an automatic crossing gate, a balanced gate pivoted tor movement in a vertical plane, a pair ot rails insulated from the remaining rails in a railway track, a relatively small spring motor having a driven shaft, a crank arm thereon, opera tive means connecting the crank arm to the gate so as tomove it from open to closed position and troni closed to open position, means :tor locking the motor against movement when the gate is in open position, means actuated b v the establishing of a circuit across the rails for releasing the locking means, second means for again locking the motor when the arm has rotated through 180, and second means for releasing the motor, said second releasing means being actuated by the breaking of the circuit across the rails.

3. In an automatic crossing gate, a balanced gate pivoted for movement in a vertical plane, a pair of rails insulated from the remaining rails in a railway track, a relatively small spring motor adapted by sucessive periods of movement in the same direction to move the gate trom open to closed position and :trom closed to open position respectively, means for locking the motor against movement when the gate is in open position, means actuated by the establishing o'f a circuit across the rails tor releasing the locking means, second means tor again locking the motor when the gate has reached closed position, and second means for releasing the motor, said second releasing means being actuated by the breaking of the circuit across the rails.

4c. In an automatic crossing gate, a balanced gate pivoted for movement in a vertical plane. a pair of rails insulated 'from the remaining rails in a railway track, a relatively small spring motor adapted by successive periods ot movement to move the gate from open to closed position and from closed to open position respectively, means for locking the motor against movement when the gate is in open position, means actuated b v the establishing of a circuit across the rails tor releasing the locking means` second means for again locking the motor When the gate has reached close-d position, and second means for releasing the motor, said second releasing means being actuated by the breaking of the circuit across the rails.

5 In an automatic crossing gate, a gate pivoted to move from open to closed position and Yfrom closed 'to open position, a pair of rails insulated from the remaining rails in a railway track, a motor adapted by successive pcriods ol' movement in the same direclion lo move the gate trom open to closed position and from closed to open position respectively. means for locking the motor against movement when the gate is in open position, means actuated by the establishing oi a circuit across the rails for releasing the locking means, second means `t'or again locking the motor when the gate has reached closed position, and second means tor releasing the motor, said second releasing means being actuated by the breaking ot' the circuit across the rails.

6. A control mechanism for a spring driven motor adapted by successive periods of rotation in the same direction to move a railway crossing safety device trom inoperative position to operative position and from operative to inoperative position respectively, including a pair of rails insulated irom the remaining rails in a railway track, means tor locking the motor aga-inst movement when the gate is in open position, means actuated by the establishing of a circuit across the rails for releasing the locking means, second means for again locking the motor when the gate has reached closed position, and second means for releasing the motor, said second releasing means being actuated by the breaking of the circuit across the rails. l

7. In an automatic crossing gate, a balanced gate pivoted for movement in a vertical plane from open to closed position obstructing a street and from closed to open position, a relatively small spring motor for moving the gate in either di rection. a pair ot rails insulated troni the remaining rails in a railway track. and electrically controlled means `tor controlling the rotation ot the motor` said latter means being controlled by the establishing and breaking ot a circuit across the rails.

8. ln an automatic crossing gate, a balanced gate pivoted tor movement in a vertical plane from open to closed positions and from closed to open positions, a relatively small spring motor adapted, by successive periods ot movement in the same direction, to actuate the gate from open to closed and from closed to open positions, respectively. a pair ot rails insulated from the remaining rails in a railway track, and electrically controlled means actuated by the making and breaking, respectively, of a circuit across the rails tor successively allowing the starting` of the motor.

9. In an automatic crossing gate, a balanced gate pivoted for movement in a vertical plane from open' to closed positions and from closed to operi positions, a' relatively small spring` motor adapted, bv successive periods of movement in the same direction, to actuate the gate from open to closed and from closed to open positions, respectively, a pair of rails insulated from the remain- ,ingl railsl in a railway track, electrically controlled means actuated by the makingand breaking of a circuit across the rails for allmvingthe motor to begin said periods of movement, and autonuitic means for stoppinp1 the motor at the end of said periods of inoiement.

l0. ln an automatic crossing` gate, a bal.- anccd grate pivoted for niovemcnt in a verticalV plane, a pair of rails insulated from the remaining' rails in a railwagiv track, a relativelyv small spring' motor adapted by successive periods of movement in the same direction to more the pate from open to closed posit-ion and from closed to open position, respectively, means for locking the motor against movement when the gate ,is in open position, means actuated b v the estaliilishinp of a circuit across the rails for releasing` the locking' means, second means for again locking the motor when the gate has reached closed position, second means for releasing` the motor, said second releasing means being actuated bv the breaking, of the ii'ircuit across the rails, and auxiliary means for cansino; the second releasing;l means to operate while the circuit remains established across the rails.

ll. in an automatic crossingl gate, a gate, a motor for actuating); the grate including' a spriugrdriven power shaft, a governor shaft Areared to the power shaft in ratio ascendingl from the power to the governor shaft, means carried bv the power shaftto transmit movement to the grate, a brakingY arm hava -frictional connection with the governor shaft, and mounted for rotation therewith, and au eleetricalliAY controlled member movable. into the rotational path of the braking' arm. i

l2. in au automatic crossing` gate, a pair of `ails insulated from the remaining rails of a railwa;v track, a grate, a motor for actuatiue` the 1rate including` a spring,` driven power sl'ia'ftlx means carried b v the power shaft to transmit movement to the gate, a governinshaft reared to the power shaft .in ratio ascending from the power to the governor shaft, a pair of braking arms having' frictional connections with the governor shaft and mounted for rotation therewith, a first trigger member cxtendiuav normally iut-o the path of rotation of one of said brakingl arios, means actuated by the closing of a circuit across the rails'for moviupY said trigger to inoperative position, means for retaining` said trigger in inoperative position until the power shaft has rotated through a predetermined arc, a. second trigger men'iber movable into the path of rotation of the other braking arm, and means for moving said second trigger to operative position when the power shaft has rotated a predetermined are.

13. ln an automatic crossing gate, a pair of rails insulated from the remaining` rails of a rail my track, a gate, a motor for movil@l the gate including a spring driven power shaft, a governor shaft `geared there.- to in ratio ascending` from the power to the governor shaft, a pair of arms mounted for rotation with said `L`governor shaft, a first trigger member disposed normally in the path of one of said arms, means actuated by the establishing of a circuit across the rails to release said trigger, a second trigger member movable into engagement with the other arm, means for moving` `said second trigger into operative position when the power shaft has rotated through a predetermined arc, said last means being reudered inactive bv the breakini.; of the circuit across the rails.

il. ln an automatic crossing;` gate, a pair of rails insulated from the remainingrails of a railway track, a gate, a motor for moving the grate including a spring driven pow-` er shaft, a governor shaft geared thereto in ratio ascending` from the power to the governor shaft, a pair of arms mounted for rotation with said governor shaft, a first trigger member disposed normally in the path of one of said arms, means actuated by the establishing .of a circuit across the rails to release said trigger, a second trigrrger member movable into engagenlent with the other arm, means for moving said second trigger into operative position when the power shaft has rotated through a predetermined arc, said last means beingjrendered inactive by the breaking of the circuit across the rails, and means'for retaining the i'irst trigger in inoperative position until. the power shaft has rotated through a predetermined arc'greater than the aforementioned arc.

Signed at Beursen, in the countyv of Plvniouth and State of Iowa, this 20th da7 of hilary, 1924-.

WILLIAM HARDER.

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