US1943625A - Crossing signal - Google Patents

Description

Jan. 16, 1934. D` w RICHARDS 1,943,625

CROSSING SIGNAL Filed Feb. 29, 1952 :s sheets-sheet 2 www ArroR/vfx D. W. RICHARDS CROSSING SIGNAL dan. 16, 1934.

3 Sheets-Sheet 3 Filed Feb. 29, 1932 latch means for Patented Jan. 16, 1934 CROSSING SIGNAL Daniei W. Richards, Roanoke, Va., assignor to Magnetic Signal Co., Los Angeles, Calif., a corporation of California Application February 29,1932. Serial No. 595,816

12 Claims.

My invention relates to signals of the character used at railway-highway crossings to warn traic on the the highway of the approach of traflic on the railway, and further relates to a signal of this character having a banner which moves from clear position to danger position and lights which are flashed when traiic is approaching the crossing on the railway.

It is an object of my invention to provide a device of the above character having a signal member which is actuated by potential or stored energy to produce a danger signal sensible to persons in proximity thereto, this signal device having means for producing a clear condition of F the signal member or means and retaining such signal member or means in such clear positio n. For instance, the signal may include a part adapted to move from clear position to danger position by gravity or under force of a spring, and in response to such movement produce a signal which may be the ringing of a bell, flashing of a light, or the appearance of a sign or banner. After the passing of a vehicle, commonly referred to as a train, from the portions of the railway tracks adjacent the signal device, power means forming part of the signal device return the signal member or means to clear position, where such signal member or means is held by a latch until the control element oi the signal device is again actuated as the result of the approach of a train on the railway.

In the preferred form of my invention I prefer to employ in the signal device a signal member consisting of a banner or me ber which is readily visible when in exposed position, this banner being supported so that it tends to move, by the potential or stored force of gravity, from a raised or concealed position to a lowered or exposed position. Associated with the banner is a power means for raising it to concealed position and a holding it in concealed position after it has been raised to such position by the power means. In the simplest form of the invention the banner moves in a vertical direction from concealed to exposed position, thereby using the weight oi the banner as a means for producing movement of the banner from concealed to exposed position, but it is contemplated that the banner may be moved in other directions than vertical by use of weights or springs in which potential energy is stored as the result of movement of the banner and its associated parts from exposed position to concealed position.

It is an object of the invention to provide a railway crossing signal which is power-operated (Cl. @Mi-130) to clearV position and automatically operated to danger position; which is held in clear position by means ci a latcliing device and automatically actuated to danger position upon release of the latching device; which is electrically operated and automatically moves to danger position upon fail-A ure of the electric current; which has a clutch associated with a rotating member for moving the signal to clear position; in which the clutch may also serve as a latch to hold the signal in clear position; in which either the latch or the clutch, or both, are magnetically controlled; in which signal lights may be employed, having means utilizing a single source of power for the purpose of alternately operating the mechanism and flashing the signal lights of the signal device; which is pneumatically o-r hydraulically .Operated to clear position and is automatically operated to danger position by means of an electromagrlf.ti-Y cally controlled valve; Which is pneumatically or hydraulically held in clear position and auto; matically actuated to danger position by means of an electromagnetically controlled valve; which is pressurefretained in condition to indicate a clear crossing and automatically actuated tu 8G danger position upon release ci pressure; and which has in conjunction therewith a heating means to counteract adverse weather influences.

Furtherobjects and advantages ci the inven-y tion will be made evident throughout the f ollowv-A ing part of the specification.

Referring to the drawings, which are for illusf trative purposes only,

Fig. l is an elevational View rsl'iovving a preferred form of my signal. Fig. 2 is an enlarged front .elevation of the signal housing with the cover plate therecf removed.

Fig. 3 is a cross section on a plane represented by the line l3--3 of Fig. 2. 95 Fig. 4 is an enlarged cross section on a plane represented by the line f4 of Fig. 2.

Fig. 5 is an enlarged fragmentary perspective view of the upper end of the banner supporting bar of the invention, showing heater contacts thereon.

Fig. 6 is a vertical cross section on a plane rep,- resented by the line 6-6 of Fig. 5.

Fig. '7 is a wiring diagram showing the manner in which the parts of the device illustrated in thepreceding figures are electrically connected.

Fig. 8 is a fragmentary section showing an alternative form of ,clutch and catch mechanism which may be used in the practice vof the invention. 1 1o Fig. 9 is a schematic view showing still another form of clutch and catch means.

In Fig. 1, I show my signal device 11 mounted on a standard 12 of such height that it may be readily viewed by approaching trarTic above the tops of vehicles. As better shown in Figs. 2 and 3, the signal device 11 includes a housing or supporting structure 13 having a side wall 14 of oval shape, there being a web forming a back wall 15 across the upper portion of the side wall 14 and a removable cover plate 16 forming a front wall for the upper portion of the housing. The lower edges 17 of the walls 15 and 16 lie in the same horizontal plane and therefore leave an opening or space 18 through the lower portion of the housing 13, said space having a height substantially equal to the width thereof. In the lower portion of the chamber 26 formed between the walls 15 and 16, walls 21 and 22 form a housing 23 for a motor 24 and other mechanism which will be hereinafter described. The front wall 22 of the motor housing 23 has a vertical channel 25 therein, and along the edges of the channel 25 guide plates 26 are secured to the wall 22, with 'the edges 27 of the guide plates 26 projecting toward each other in a manner to engage vertical grooves 28 formed on opposite sides of a vertical bar 30 to which a display member or banner 31 is secured. On the leftward side of the bar 30, teeth are cut to form a rack 32 which is engaged by a relatively small spur gear 33 mounted on the forward end of a shaft 34 which, as shown in detail in Fig. 4, is mounted in bearings 35 and 36 in the walls 15 and 22, the gear 33 being secured to the leftwardly or forwardly projecting end 37 of the shaft by means of a pin 38.

Turnably mounted on the shaft 34 adjacent the inner end of the bearing 36 is a clutch member 40 having a radial wall 41 and a worm gear 42 adapted to be engaged by a worm 43 mounted on a shaft 44 which projects from the motor 24 and is driven by such motor. Accordingly, it will be seen that when the motor is operated, the

worm 43 will rotate the clutch member 46 and that when the motor is at rest, the clutch member 40 cannot rotate in View of the fact that the worm gear 42 is engaged by the worm 43. Ad-

jacent the clutch part 40 a second clutch part 45 face 52 of the wall 41.

' sulating material.

is non-rotatably mounted on the shaft 34 by means of a key 46, the second clutch part 45 having a radial wall 4'? carrying a plurality of electro-magnets 48 having cores 49 so placed that their forward ends 51 may engage the radial The electro-magnets 43 are adapted to be energized through rings 53 and 54 mounted on a cylindrical outer wall 55 of in- On a projecting bracket 56 spring brushes 57 and 58 are secured in such positions that the ends thereof will engage the rings 53 and 54 of the clutch part 45.

On each side of the supporting structure 13 light housings 60 are formed, these light housings being cylindrical and having shields 61 secured at the ends thereof by means of screws 62. Each shield 61 preferably supports a red crystal lens 63 through which the light from electric lamps 64 and 65, indicated in Fig. 7, is flashed during the time a warning signal is being given. For the purpose of illuminating the lamps 64 and 65 I provide a movable switch member 66 adapted to alternately engage contacts 67 and 68 mounted on brackets 69 within the housing. The movable switch member 66 is mounted on the outer portion 70 of a lever 71 which is pivoted at 72 and has a follower 73 at its inner end engaging a cam 74 formed on the clutch member 40. As will be hereinafter explained, rotation of the cam 74 causes the switch member 66 to alternately engage the contacts 67 and 68, thereby alternately illuminating or hashing the lamps 64 and 65 which are situated in the light housings 60.

In Figs. 2 and 3 the banner 3l is shown in lowered or danger position within the space 18 oi' the supporting structure 13 and between the light housings 60. It is supported in this position by means of a lug 76 which consists of a body secured to the back portion of the upper end of the bar 30 by means such as screws 77 so as to engage a resiliently mounted stop member 78 which is formed at the leftward end of a lever 8G pivoted at 81 to the supporting structure and being yieldably maintained in horizontal position by means of a spring 82 which surrounds an upwardly extending bar 83. The lower end of the bar 83 is pivotally connected at 84 to the lever 80 and extends upwardly through a horizontal wall 35 forming part of the housing 13. The spring 82 is supported on the upper face of the wall 85 and forces upwardly against a nut 86 on the upper end of the bar 83.

Within the chamber 2G is a switch actuating member 37 consisting of a level' pivoted at 33 and having a portion 96 adapted to be engaged by the upper end of the bar 30 when the bar is moved into raised position. When the end 9i) is forced upwardly against the force of a spring 91 which is mounted on a rod 92 and engages the leftward end 93 of the member 37, the end 93 is moved downwardly so as to withdraw a body of insulation 94 from engagement with a switch member 95, allowing such switch member to spring downwardly and to thereby disengage itself from a stationary contact 96. The parts 95 and 96 constitute a control switch 97 for stopping the motor 24 when the banner 31 has been raised from the lowered position in which it is shown in Figs. 2

and 3 to the raised or clear position in which it Y is shown by dotted lines 98 in Fig. 1 within the chamber 20 of the supporting structure.

My invention also provides means for heating the chamber 20 and the parts therein so that during extremely cold weather moisture or other material within the housing will not become frozen and interfere with the operation of the signal. the chamber' 26 I show a heating element 10G. Figs. 6 and 7, which heating element may be placed in a vertical opening 101 formed in any desired manner in the bar 30. From the upper end of the heating element wires 102 are carried to contact plates 103 carried by a body of insulating material 104 secured to the upper end of the bar 30 by means of screws 105. In the upper portion of the chamber 20 I mount a pair of contacts 106 adapted to engage the contact plates 103 when the bar 30 is in raised position. By means of conductors 108 and 109, Fig. 7, the contacts 166 are connected to electric supply conductors 110 and 111 which are shown connected to a source of electrical energy 112 in the form of a As a means for producing heat within vv-nected -with placed in position to be engaged by the plates 103 when the bar 36 lis vin lowered position :so that electricity can be supplied to the heating element l-100 at such time.

The operation Aof my device is as follows: Any standard form of track relay 115 may be vemployed for 'controlling the operationof my signal. In Fig. 7, I have shown an electromagnet 116 adapted to be energized through conductors 117 land `118 which Aare respectively connected to rails 12'0 and 121 of a track 122. Across the rails 120 and A121 `a ltrack battery 123 and a resistor 124 are connected, as shown. When no railway vehicle is Yon the rails 120 and 121, the -electromagnetl'fl will be energized and will hold lan arma- 'ture 125 in raised position, holding a contact 126 mounted on Athe armature 125 in engagement with a'contact 127 and closing a circuit 128 which is'connected with thebrushes 57 and 58, such circ'uit `consisting of aconductor 130 which connects the armature 125 with the feed conductor 110, the armature 125, a conductor 131 extending from the contact 127 to the brush 58, and aconductor 132 extending from the brush 57 to the feed conductor 111, the result being -that when the larmature 125 is raised, the electromagnets 48 yof ltheclutch member 45 will be energized and the radial wall 4l of the member 40 will be magneticall-y pulled against lthe ends 51 of the cores 49 with such `force that the vclutch member 45 -cannot Ebe readily turned. Accordingly, assuming that the banner 31 is in raised position, with the vupper -end of the bar engaging the end 90 Aof the member 87, and that the electromagnets 148 of the lclutch member 45 Aare energized, the hold-ing of the shaft 34 and the gear 33 against rotation .prevents the bar 30 from `moving downwardlyowing to the -fact that the rack 32 formed 'thereon is engaged by the gear 33. Therefore, the magnetic clutch operates as a means for maintaining the signal in clear condition or posiltion yas long `as the track is open. Should a railway vehicle .move onto the rails 120 vand 121 and thereby short circuit 'the .electromagnet 116, the armature 125 will fall, breaking the circuit 128 (by moving the contacts 126 and 127 apart, with :the result that Vthe `electromagnets 48 will be de- Aenergized, releasing the clutch part and permitting rotation of the spur gear 33 and dropping vof the bar 30 andthe banner 3l from raised position :to lowered position, the downward movement of .the bar 30 vbeing stopped `by the engage- .ment of the lug'76 with the resiliently maintained stop member 78.` As the bar 30 moves ydownwardly from raised position, the member 87 is `released and the switch member 95 is moved into engagement with the contact 96, thereby closing Vthe Aswitch 97 in the conductor 110, with the result'that electric current from the source 112 is lpermitted to flow through the motor 24, whereupon .the worm 43 drives the gear 42 of the clutch r part 40 in an anti-clockwise direction, as viewed ,in Figs. 2 and 7.

Consequently, the cam 74 is rotated, causing 'the switch member 66 to swing 'back Aand forth from the contact 67 to the con- :tact `68. At this time the armature 125 is in lowered position, and a contact 133 formed thereon engages a contact 134 which is connected 'through a conductor 135 and the lever 71 with 'the switch member 66. From the contacts 67 and 68 conductors 136 and 137 are carried to the lamps Aand 64, and the lamps are in turn conthe current supply conductor 111 by ',use fof conductors 138 rand y146. As vlong as the .imotor tur-ns the -cam 74 and as long las Athe contact 133 is in engagement with the I,contact 134, the switch member 66 will be alternately caused to engage the contacts 67 and `A68so as to :produce an alternate illumination of 'the lamps 64 vand 65. When the .railway vehicle `leaves the rails 120 and 121 so that the electromagnet 1:16 is again energized so as to Vmove the armature 1.25 into raised position, the contact 126 will be brought into .engagement with the contact 127, thus closing the circuit 128 which :connects through the :brushes 57 and 58 with the electromagnets 48 of the clutch member 45, with the result that the members 4 0 and 45 are magnetically pulled together and the member 45 is -consequently caused to rotate with `the member 140, transmitting rotation through the shaft 34 to the gear 33 in anti-clockwise direction :so that rotation of the gear 33 in engagement with the rack 32 will move the bar 30 and the banner 31 upwardly. When .the upper end vof the bar 30 engages the end of the member v87, the switch 97 will be opened, thus vbreaking the fmotor circuit and stopping the vmotor with the banner 31 in concealed or clear position. Due to the disengagement of the contacts 133 `and 134, the circuit including the lamps 64 and 65 will be broken so that there will be Ano -illumination thereof. The only parts of the device'wh-ich remain energized are the heating lelement and the electromagnets 48 which serve to hold the parts 40 and 45 together so that a magnetic catch lor latch is thereby provided for holding the banner 3l in raised or clear position. The weight of the banner 3l and the bar 30 -is sufficient to l.break out any snow or sleet which might collect Vin the lower part 18 of the supporting structure 13, and, as previously explained, the bar 30 may be heated during cold weather so that it cannot freeze, and sufcient heat may be provided within the upper portion of the housing of the signal to prevent accumulation of ice therein or the freezing together of parts thereof during 4cold Weather.

In Fig. 8, I show an alternative form -of magnetic clutch mechanism in which l.the electromagnets do not rotate. In this form of the -device the shaft 34 Vhas bevel gears 145 r`and 1.46 turnably mounted thereon. On the gear 145 .a worm gea-r 147 is formed adapted to be driven by the worm 43, and on the gear 146 vthere .is a radial plate 148 extending in close proximity to the faces of cores 150 of -electromagnets 48a mounted on a stationary wall 151. Between .the gears 145 and 146 a planetary pinion 152 is mounted on a frame 153 which is secured to the shaft 34 by means of a pin 154. In consequence of this arrangement the shaft 34 `cannot turn when the gear 145 is held stationary by the worm 43, and the gear 146 is held stationary by energization of the electromagnets 48a. Also, when the electromagnets 48a are deenergized and the gear 146 is released so that it may rotate on the shaft 34, the planetary gear -152 may roll around the gear 145, permitting the shaft v3.4 to rotate, as occurs during the dropping of .the banner 31 from concealed to exposed position. Furthermore, when the worm 43 is rotated by the motor 24 and the gear 146 is held stationary as the result of energization of the electromagnets 48a, rotation of the gear 145 will cause the planetary gear 152 to roll around the Vgear 146, thereby rotating the shaft 34 and lifting the banner 31 from exposed position to concealed position.

The Vform of clutch mechanism .shown .in .F.ig.

`9 employs a worm gear 160 turnably mounted on 51150 GIS the shaft 34. Splined to the shaft 34 adjacent the worm gear is a collar 161 having clutch teeth 162 adapted to engage clutch teeth 164 formed on the worm gear 160. An electromagnet 165 is adapted to attract an armature 166 mounted on a lever 167 which is pivoted at 168 and has forks 170 for engaging and moving the collar 161. The lever 167 is engaged by a tension spring 171 which exerts a force tending to rotate the lever 167 in a direction to move the collar 161 into a position of disengagement as shown in Fig. 9. The electromagnet 165 and the armature 166 are so placed thatthe pull oi the electromagnet 165 will swing the lever 167 in a direction to produce engagement of the clutch teeth 162 and 164. Fig. 9 discloses a motivating and latching connection for use between the motor 241 and the banner 31, said connection having mechanically engaging clutch or latch elements which are magnetically controlled, naking it possible to connect the electromagnet 165 to the wires 131 and 132 of the circuit 128 and to thereby control the raising and lowering of the banner 31 without the use of moving electromagnets, such as the electroinagnets 43, and by the use oi the parte 162 and 16e which do not depend upon friction to maintain them in stationary relationship.

Although I have herein shown and described my invention in simple and practical form, it is recognized that certain parts or elements thereof are representative of other parts, elements or mechanisms which may be used in substantially the same manner to accomplish substantially the same results; therefore, it is to be understood that the invention is not to be limited to the details disclosed herein but is to be accorded the full scope or the following claims.

I claim as my invention:

i. A crossing signal oi the character described, including: a supporting structure having a shield chamber with an opening at its lower end; a banner supported by said structure, said banner normally tending to reside in an exposed position below said opening but being movable to a concealed position within said shield chamber; withdrawing means for moving said banner from exposed position to concealed position; releasable means for holding said banner in concealed position; control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said banner to move from concealed position to exposed position7 and for actuating said withdrawing means when said vehicle leaves said trackage whereby to move said banner into concealed position; and means ior producing heat within said shield chamber.

2. A crossing signal of the character described, including: a supporting structure having a shield; a banner supported by said structure, said banner normally tending to reside in an exposed position but being movable to a concealed position behind said shield; withdrawing means for moving said banner from exposed position to concealed position, said withdrawing means comprising an electric motor and parts operatively connecting said motor to said banner; electrically operated means for holding said banner in concealed position; and electrical control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said banner to move from concealed position to exposed posi- Leiaees tion, and for actuating said withdrawing means when said vehicle leaves said trackage whereby to move said banner into concealed position.

3. A crossing signal of the character described, including: a supporting structure; a banner supported by said supporting structure in a manner to move by gravity from clear position to danger position; withdrawing means for moving said banner from danger position to clear position, said withdrawing means comprising an electric motor and parts operatively connecting said motor to said banner; electrically operated means for holding said banner in clear position; and electrical control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said banner to move from clear position to danger position, and for actuating said withdrawing means when said vehicle leaves said trackage whereby to move said banner into clear position.

e. A crossing signal of the character described, including: a supporting structure having a shield and a space adjacent said shield; a display membei' supported by said supporting structure in a manner to move by gravity from a position behind said shield to an exposed position in said space; a motor for movinD- said display member from said space to a position behind said shield; an electrically released latch means for holding said display member in concealed position behind said shield; and control means associated with trackage for reeasing said latch means in consequence of thc presence of a railway vehicle on said trackage, whereby to permit said display member to move from concealed position to exposed position, control means also controlling the operation of said motor to move said display member from said space to a position behind said shield in consequence of said vehicle leaving said traclrage.

5. A crossing signal of the character described, including: a supporting structure having a shield chamber provided with an opening at its lower end commtmicating with an open space below said shield chamber; signal means movably supported by said supporting structure so as to move by gravity from clear position within said shield chamber to danger position in said open space; a motor for moving said signal means to clear position; a motor circuit for energizing said motor, there being a switch in said motor circuit for opening said motor circuit when said signal means reaches said clear position; means for holding said signal means in said clear position after it has been moved thereinto by said motor; control means for said holding means, said control means being operated by a ow of electrical energy through a control circuit and be'- ing adapted to release said holding means in consequence of a reduction in the flow of electrical energy through said control circuit; and means for providing heat witl in said shield chamber.

6. A crossing signal of the character described, including: a supporting structure; signal means moi/ably supported on said supporting structure; a motor for moving said signal means to clear position; a motor circuit for energizing said motor, there being a switch in said motor circuit for openino said motor circuit when said signal means reaches said clear position; transmissionY means connecting said motor to said signal means, said transmission means comprising a primary part adapted to be moved in positive direction by said motor, a secondary part connected to said signal means, said secondary part being adapted to engage said primary part, and means for preventing reverse movement of said primary part; means for releasably holding said secondary part in engagement with said primary part; and control means for association with trackage for releasing said holding means in consequence of the presence of the railway vehicle on said trackage.

7. A crossing signal of the character described, including: a supporting structure; signal means movably supported on said supporting structure; a motor for moving said signal means to clear position; a motor circuit for energizing said motor, there being a switch in said motor circuit for opening said motor circuit when said signal means reaches said clear position; transmission means connecting said motor to said signal means, said transmission means comprising a primary part adapted to be moved in positive direction by said motor, a secondary part connected to said signal means, said secondary part being adapted to engage said primary part, and means for preventing reverse movement of said primary part; magnetic means for releasably holding said secondary part in engagement with said primary part; and control means for association with traclage for de-energizing said magnetic means whereby to release said secondary part in consequence or the presence of a railway vehicle on said trackage.

8, A crossing signal of the character described, including: a supporting structure; signal means movably supported on said supporting structure; a motor for moving said signal means to clear position; a motor circuit for energizing said motor, there being a switch in said motor circuit for opening said motor circuit when said signal means reaches said clear position; transmission means connecting said motor to said signal means, said transmission means comprising a primary part, a worm and gear connecting said primary part to said motor so that said primary part will be moved in positive direction by said motor, and a secondary part connected to said signal means, said secondary part being adapted to engage said primary part, said worm and gear preventing reverse movement of said primary part; magnetic means for releasably holding said secondary part in engagement with said primary part; and control means for association with trackage for die-energizing said magnetic means whereby to release said secondary part in consequence of the presence of a railway vehicle on said trackage.

9. A crossing signal of the character described, including: a supporting structure; walls on said structure providing a shield chamber having an opening at its lower end; a display member movable vertically within said shield chamber from normally exposed position in front of said opening to concealed position above said opening; means for elevating said display member from exposed position to concealed position; releasable means for holding said display member in concealed position; guide means for guiding said display member during its movement in said shield chamber; and control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said display member to move from concealed position to exposed position, and for actuating said withdrawing means when said vehicle leaves said trackage whereby to move said display member into concealed position.

l0. A crossing signal of the character described, including: a supporting structure having Walls providing a shield chamber having an opening at its lower end; a display member enclosed within the walls of said chamber and being movable vertically from normally exposed position in front of said opening to concealed position above said opening; withdrawing means for moving said display member from exposed position to concealed position; means .for guiding said display member during its movement in said chamber; means for holding said display member in concealed position; and control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said display member to move from concealed position to exposed position, and for actuating said withdrawing means when said said vehicle leaves said trackage whereby to move said display member into concealed position.

11. A crossing signal of the character described, including: a supporting structure; walls on said structure providing a shield chamber having an opening at its lower end; a display member movable vertically within said shield chamber from normally exposed position in front of said opening to concealed position above said opening; means for elevating said display member from exposed position to concealed position; releasable means for holding said display member in concealed position; guide means for guiding said display member during its movement in said shield chamber; control means associated with trackage for releasing said holding means when a railway 115 vehicle is on said trackage, so as to permit said display member to move from concealed position to exposed position, and for actuating said withdrawing means when said vehicle leaves said trackage whereby to move said display member 120 into concealed position; and means for producing heat within said shield chamber.

12. A crossing signal of the character described, including: a supporting structure having walls providing a shield chamber having an opening at 125 its lower end; a display member enclosed within the walls of said chamber and being movable vertically from normally exposed position in front oi said opening to concealed position above said opening; withdrawing means for moving said display member from exposed position to concealed position; means for guiding said display member during its movement in said chamber; means for holding said display member in concealed position; control means associated with trackage for releasing said holding means when a railway vehicle is on said trackage, so as to permit said display member to move from concealed position to exposed position, and for actuating said withdrawing means when said vehicle leaves said 140 traokage whereby to move said display member into concealed position; and means for heating said shield chamber.

DANIEL W. RICHARDS.

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