Patent GB-509151-A (GB)
Title: Improvements in track-actuated train-control apparatus
IPC: B61L3/00
Filed: 1938-01-11
Abstract: 509,151. Automatic train-control apparatus. HASLER AKT.-GES. WERKE FUR TELEPHONIE UND PRAZISIONS-MECHANIK. Jan. 11, 1938, No. 923. Convention date, Jan. 11, 1937, [Class 105] A train-control apparatus actuated by impulses from the track and adapted to impose a predetermined fixed speed limit or a speed limit decreasing as the train travels forward but allowing such limits to be cancelled and requiring an alert push to be operated comprises a set of polarized relays 63 ... 66, the first of which is dropped on receipt of the first impulse, such relay 63 starting axle-driven control shafts 99, 104, 131, 142 into operation whereby later impulses drop the relays 64 ... 66 according to the distance location of the impulse and whereby the speed limits and alertness test are imposed ; the predetermined fixed speed limit is imposed when the relay 64 is dropped by a second impulse if received within a short distance the magnitude of the limit being determined by this short distance but otherwise-a continuously decreasing limit is imposed ; in the case of the fixed speed limit it is not necessary for the driver to operate the alert push. The whole apparatus is returned to normal by the relay 65 dropping if an impulse is received within a medium distance and the apparatus is at once ready for the imposition of another speed limit control ; but if the cancelling impulse is not received till beyond such medium distance then the relay 66 is dropped which only cancels the decreasing speed limit, if such is in force, whereas the fixed speed limit, if in force, remains imposed, the whole apparatus not being returned to normal until the section has been traversed. Fig. 5 shows the impulse receiving portion of the apparatus. When the locomotive is travelling front foremost the switch 37 is in the position shown and the impulse causes closure of a contact 165. The first impulse passes by contact 16 and contacts 18, 20 to the polarized relay 63 which drops its armature and thereby starts' the operation of the apparatus, as described later. The axle-driven shaft 99 accordingly begins to rotate and changes over the contact 18 so that a second impulse if received within 180 metres will pass over contact 18 at the right and contact 21 at the left to the polarized relay 64. If an impulse is received at 180-360 metres it passes over contact 18 (returned 'to the left) and contact 20 at the right to the polarized relay 65. If an impulse is received after 360 metres it passes over contacts 18, 21 both at the right to the polarized relay 66. To ensure an early second impulse passing to the relay 64 a contact 16 is operated to the right by a fast-running axledriven shaft 142 ; thus an early second impulse passes over the contact 16 at the right, a front contact 27 of the polarized relay 64, and contact 21 at the left to the polarized relay 64. Referring now to Figs. 1 and 1A it will be seen that when the armature 79 of the polarized relay 63 drops it causes the middle springs 22, 23 to be latched in the dropped position and allows the lower spring of contact 22 by its brief contact with the middle spring to apply potential to a magnet 60, Fig. 1A, and to a magnet 55, Fig. 1. The magnet 60 rocks a lever 88 whereby a stop rod 91 is withdrawn from an axle-driven pawl 85 which thereupon drives the shaft 99 ; the lever 88 is latched up by a lever 87. The magnet 55 operates a rod 113 whereby stop levers 109, 121, 126 are retracted to allow axle-driven pawls 107, 123 to drive the shafts 104, 131 and a holding pawl 127 to engage a shaft 142 ; the stop levers 109, 121 and 126 are respectively latched up by the armatures 112 and 119 of magnets 54. 56. The drive of shaft 104 is thus stopped if the armature 112 is operated by a manual "alert" push 118 or if the magnet 54 is energized by an "alert" button Wt (Fig. 1A). The magnet 56 is energized over a back contact of the polarized relay 65 to unlatch the lever 121 and thereby to stop the drive of the shaft 131 and to remove the holding pawl 127 from the shaft 142. The shafts when released are automatically returned to the normal position by torsion springs. A back contact of the relay 65 also energizes a magnet 57 which unlatches the stop rod 91 to release the shaft 99. The stop rod 91 also effects the closure of contact springs 33 whereby a magnet 61 is energized to unlatch the middle contact springs of the polarized relays 63 ... 66. Such action returns the apparatus to the normal condition. The speed-limit control apparatus is shown in Fig. 6. When the first impulse drops the polarized relay 63 its latched-down back contact 22 applies potential over front contacts 26, 32 of the polarized relays 64, 66 to the middle springs of contacts 10, 11, a spring contact 8 and to a clutch 62 whereby the shafts 137, 142 are driven from the axle. The contact 8 lights lamps 154, 154<1> warning the driver to operate his "alert" push; if he does not do so then a shaft contact 9 will close and energize a magnet 5 by which a brake magnet Bra will be energized to effect a braking and to light lamps 156, 156<1>. The contact spring 10 if allowed to make its lower contact will likewise energize the magnet 5 to effect a braking; the contact spring 11 will just previously light lamps 155, 155<1> to warn of the imminence of braking. To prevent the braking it is necessary that the speed be reduced in accordance with the distance since the axle-driven cam 133 lowers the right-hand end of a link 147 and thus tends to close the springs 10, 11 on to their lower contacts and to counteract this it is necessary that the speed be reduced to move the cam 129 clockwise and so allow the lefthand end of the link 147 to rise. If a second impulse is shortly afterwards received to drop the polarized relay 64 the potential from the back contact 22 of the polarized relay 63 becomes applied over the back contact 26 of the polarized relay 64 and front contact 29 of the polarized relay 65 to the middle spring of a contact 13 ; the potential is no longer applied to the clutch 62 nor to the springs 8, 10, 11. Accordingly the shafts 137, 142 stop at a certain setting (determined by the location of the second impulse) and so impose a certain fixed speed limit by means of a cam 143 which acts on one end of a link 149 the other end of which is acted upon by a speed cam 130. A low speed limit is imposed by an early second impulse because the cam 143 will not have moved far counter-clockwise and accordingly the speed must be considerably reduced to move the speed cam 130 clockwise and allow the left-hand end of the link 149 to rise sufficiently for the contact 13 to open and so avoid energizing the magnet 5. When a fixed speed-limit is thus imposed the alertness test is automatically cancelled by the magnet 54 being briefly energized from contact 22 of the relay 63 over the bottom contact spring 25 of the polarized relay 64 while dropped. The speed limits whether fixed or continuously decreasing are cancelled by a third impulse received at 180-360 metres which will drop the polarized relay 65 whereby the apparatusis at once returned to normal because the magnets 56, 57 are energized to release the shafts and unlatch the contacts of the polarized relays. If the cancelling impulse is not received till after 360 metres the polarized relay 66 is dropped and the fixed speed limit, if imposed, will remain until the full distance is traversed and the apparatus will only be returned to normal when the axle-driven shaft 131 has closed a contact 15. The closure of contact 15 drops the polarized relay 65 by a circuit from +ve over back contact 23 of the polarized relay 63, front contact 30 of the polarized relay 65, the contact 15, winding of the polarized relay 65 to - -ve and the dropping of the polarized relay 65 then returns the apparatus to normal as described above.