US2130452A - Speed responsive apparatus - Google Patents

Description

Sept. 20, 1938. H, BONE 2,130,452

SPEED RESPONSIVE APPARATUS Original Filed May 17, 1935 jgozated from dpiuz'nymembe Slow Pick-150.

lgolaied fi om driving membel? Slow vickiyw.

' ':r'- EP INVENTOR I I Henbe .Bone. Fly. 2 18 BY H15 ATTORNEY Patented Sept. 20, 1938 UNITED STATES PATENT OFFICE SPEED RESPONSIVE APPARATUS Original application May 17, 1935, Serial No. 22,029. Divided and this application April 2,

1937, Serial No. 134,633

8 Claims.

My invention relates to speed responsive ap- An object of my invention is the provision of novel and improved speed responsive apparatus which is actuated by electrical means, and by which an unsafe indication due to loss of power or breakage of a part is avoided.

Speed responsive apparatus embodying my invention is particularly suitable for, although in no way limited to, use in connection with speed control systems for railway trains.

This application is a division of my copend- :ing application, Serial No. 22,029, filed May 17, 1935, now Patent No. 2,103,706, Dec. 28, 1937,

for Speed responsive apparatus.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating one form of apparatus embodying my invention, and Fig. 2 is a diagrammatic view of a modification of the apparatus of Fig. 1.

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

Speed responsive apparatus embodying my invention embraces a suitable speed responsive circuit interrupting means and a time limit electromagnetic means adapted to come into action a short period after the conditions actuating it have begun to exist. As shown in Fig. 1, the circuit interrupting means is a commutator, designated as a whole by the reference character CI, and the t me limit electromagnetic means consists of two relays RI and R2 of the direct current neutral type. The shaft I of the commutator CI is operatively connected with a member the speed of whose movement it is desired to determine through the medium of any suitable drive mechanism such, for example, as a train. of gears not shown. When the apparatus is utilized to control the circuits of a speed control system for railway trains, the shaft I is preferably operatively connected with an axle of the vehicle on which the apparatus is mounted, with the result that the speed of rotation of shaft I is in accordance with the speed of the railway train. A contact brush 2 is rigidly mounted on the shaft I for rotation therewith and is adapted to engage three annular segments 3, 4 and 5, the arrangement being such that the segment 3 is a complete ring and continuously engages the brush 2, but the segments 4 and 5 span only a little over 180 and alternately engage the brush 2. It follows that with the shaft I stationary,

electrical connection is continuously completed between the segment 3 and one or the other of the segments 4 or 5, depending upon the posi-- iion of the contact brush 2, but that with the shaft I rotated, electrical connection is alter- 5 nately completed between the segment 3 and the segments 4 and 5, the duration which the connection is completed in each case being dependout upon the speed of rotation of the shaft I, and hence, in turn, dependent upon the speed of the driving member. It is to be understood, however, that my invention is not limited to any specific form of circuit interrupting means and ih commutator CI is shown for illustration only. It is clear that the commutator CI may be con- 15 structed with the segments 3, 4 and 5 mounted rigid on the shaft I for rotation therewith, and the contact brush 2 held stationary should it seem desirable to do so.

The commutator CI controls the energizing 20 circuits for the relays RI and R2, the arrangement being such that the circuits are alternately opened and closed with rotation of the shaft I. The segment 3 is connected over wire 6 with one terminal of any convenient source of direct current such as a battery 7!, and which battery is preferably of a predetermined given voltage. The other terminal of battery I is connected with one terminal of the operating winding of each of the relays R! and. R2 over wires 8 and 9, re- 30 spectively. The second terminal of the operating winding of relay RI is connected over wire III with the segment 5, and the second terminal of the operating winding of relay R2 is connected over wire II with the segment 4. Consequently, 35 when brush 2 is in the position to engage the segment 4. current flows from the battery I over wire 6, segment 3, brush 2, segment 4, wire II, operating winding of relay R2, and wire 8 back to the battery i, and the relay R2 is energized, 40 the potential difference across the terminals of the relay R2 being substantially the full voltage of the battery 1 since the ohmic resistances of wires 6, 8 and II, and the contact resistance of brush 2 with segments 3 and 4 are negligible. When the brush 2 is moved around and engages the segment 5, current flows from the battery I over wire 6, segment 3, brush 2, segment 5, wire III, operating winding of relay RI and Wire 9 back to the battery 1, and relay RI is energized. the potential difference across the terminals of the relay RI being substantially the full voltage of the battery I since the ohmic resistance of the circuit other than that of the operating winding of the relay is negligible. When the 2, since the segments l and are made to slightly overl p, as explained hereinbeiore. When the brush ii is in a horizontal position, as viewed in Fig. 3', both relays are supplied with current in parallel.

The relays Bi and are each provided with a circuit controlling armature in the usual mannor, the armature E2 of relay Rt being adapted to be raised into engagement with a front contact it when the relay is energized, and to drop out of engagement therewith when the relay is deenergized. In like manner, the armature i i of relay R2 is adapted to be raised into engagement with a front contact i5 when the relay is energized, and to ore-p away from engagement ther with when the relay is deenergized.

As set forth hereinbefore, the relays Bi and constitute a time limit electromagnetic means adapted to come into action a short period after the conditions actuating it have begun to exist, and to this end, each relay Rt and R2 is provided with slow pick-up char c 'eristics. That is to say, the armature ii of relay for example, is not raised into engagement with the front contact i3 until a predetermined time interval subsequent to initiating the energization of the relay by supplying current to its operating winding. Likewise, the armature i l of relay is not raised into engagement until a predetermined time interval subsequent to initiating energization of that relay by supplying current to its operating winding. In other words, the relays Bi and R2 each become effective to operate its respective armature a short period after current is initially supplied to the operating winding of the relay. The time delay in operating the armature is preferably the same for both relays RE and R2. Such time delay in pick-up may be accomplished in any convenient manner, several arrangements being well-known in the art for providing a direct current relay with slow pick-up characteristics.

In addition to being provided with slow pickup characteristics, the relays RS and are each provided with relatively high pick-up characteristics. For example, the relay Ri is so proportioned and adjusted that the tractive effort necessary to raise the armature l2 into engagement with the front contact is produced when the value of a current flowing in its winding is, say, 75% of the ultimate current value resulting from a potential difference across the terminals of the relay equal to the full voltage of the battery '5. Likewise, the pick-up current of relay R2 is approximately 75% of the ultimate current efiected when the full voltage of the battery is impressed across the terminals of the relay. The relays R! and R2 possess two constants-resistance and inductance. Due to inductance, the current resulting from a voltage impressed across the terminals of the operating winding does not at once rise to the value ultimately reached, that is, the value as indicated by Ohms law. It follows that with the brush stationary at the position illustrated in Fig. l, the relay R2 is supplied with current the ultimate value of which is equal to that produced by the full voltage of the battery 7, as determined by the resistance of the relay, since the inductance delays the building up of the current for a relatively short period only. Under his condition, the energization of the relay RE is sumcient to attract the armature l4 and raise it into engagement with the front contact i5 at the expiration of the slow pick-up period. If the brush 2 is rotated at a speed such that the time interval the brush 2 makes engagement with the segment during a half revolution is a little greater han the slow pick-up period of relay R2, the armature id is raised into engagement with contact duri this half revolution of the shaft l since the time constant resulting from inductance is loss than the slow pick-up period and the ultimate value ol the current as indicated by Ohiil law is effected for a sufficient length of time. During the hall revolution the brush it breaks engagement with the segment i, the energization of relay dies away to substantially zero and the armature I4 is released. Hence, at such speed of shai't i the relay R2 is picked up and released once each revolution of the shaft i. In the event the brush 2 is rotated at a speed such that the duration of the connection between the segments 3 and t by brush 2 is slightly less than the slow pick-up period of relay R2, the armature i i remains down out of engagement with the contact it. Under this condition of speed, the time interval between two successive impulses is sufficient for the energization of the relay to die away to substantially zero, notwithstanding the inductance causes a slight delay in the dying away of the current. Again, if the speed at which the brush 2 is rotated is relatively high, and rapid impulses of current are supplied to the winding of relay R2 and build up the magnetism in the magnetic circuit, the average value of the current flowing in the operating winding, however, does not reach the 75% pick-up value due to the inductance of the relay, and hence the armature l4 is not raised into engagement with contact l5 at such relatively high speeds. In other words, there is a critical speed above which the relay R2 is not picked and below which the relay is alternately picked up and released, while at zero speed the relay is steadily energized in case the brush 2 stops at a point where it makes engagement with the segment l, and the relay is deenergized in case the brush 2 stops at a point where it is out of engagement with the segment 4.

Since the relay Ri is proportioned and adjusted similar to relay R2, the operation of the relay R5 in response to the different speed conditions of brush 2 is the same as just explained in connection with relay R2, except for the fact that the circuit for the relay R! is governed during the opposite half revolution of brush 2. The speed of shaft l below which the relays R5 and R2 are picked up is hence determined by the pick-up time provided for the relays. For example, if it is desired to operate the relays RI and R52 at speeds up to ten revolutions per minute oi the shaft i, that is, one revolution every six seconds, the pick-up time would be three seconds since each relay is energized during onehalf of each revolution. Thus, at all speeds below ten revolutions per minute, each relay would be picked up while its ci cuit is closed by the brush but that at all speeds above ten revolutions per minute both relays would remain down. At zero speed one or the other of the relays R5 or R2 would be picked up, and in the case the brush 2 should stop at the horizontal position, as viewed in 1, both relays would be picked up.

The relays El and R2 may be utilized to control indication and control devices to determine whether or not the driving member is moving at all, or is moving above or below a predetermined critical speed. As here shown, relays RI and R2 govern an indication lamp l6 and a control magnet 18 by virtue of two simple circuit-s, both of which circuits include a battery Ill and one of which includes the contact l2-l3 of relay R5, and the other of which includes the contact I4--I5 of relay R2. Hence, the lamp i6 is steadily illuminated and the control magnet 18 is steadily energized when the speed of shaft 1 is zero, since at zero speed at least one of the relays RI or R2 is steadily picked up. When the speed of shaft I is not zero but is below the critical speed, and the relays are alternately picked up and released, the lamp 16 is flashed and the net 48 is intermittently supplied with current. When the speed is above the critical speed and neither relay is picked up, the lamp I6 is dark and the magnet .58 is deenergized. As here shown, the magnet 48 is provided with slow-re lease characteristics, and hence is energized at zero speed and at speeds 11 speed.

below the crh. When the apparatus of Fig. 1 is us tion with speed control systems for rai y trains, the lamp l5 may be used to indicate to the operator of the train the zero and low speed conditions, and the magnet 18 may be used to effect a control over the train. brake equipment, and when so used an unsafe indication due to loss of power or oreakago of a part is avoided.

If it were desired to have the critical speed of shaft l relatively low, additional segments may be added to the commut r. In Fig. 2, the apparatus is the same as Fig. 3., e. ct the ccrnmutator CZis provided with four annular segments I9, 26, 2! and 22, and a second contact brush 23 is mounted igid on the shaft l. Each segment !9, 23, 2! and 22 spans approximately 46 with an adjacent space of approximately 44 between each two segments, and the brush 23 is positioned with respect to the brush 2 so that when brush makes engageme with a segment the other brush is positioned at one of the insulating spaces. The battery I is connected between the segment 3 of commutator C2 and one terminal. of the operating winding of each of the relays Bi and R53 the same as in Fig. 1. The second terminal of the operating winding of relay R2 is connected with the segments 9 and 21 in parallel, and the second terminal of the opera ing winding of relay R! is connected with the segments 26 and 22 in parallel, as will be readily understood by an inspection of Fig. 2. Consequently, each relay R! and R2 of Fig. 2 receives two current impulses each revolution of the shaft I, and current is supplied to at least one of the two relays whatever the position of the contact brushes 2 and 23. With the relays RI and R2 proportioned and adjusted in the manner explained in connection with the apparatus of Fig. 1, a critical speed of 5 revolutions per minute of shaft l is provided since at such speed the duration of a current impulse is substantially three seconds, inasmuch as each segment spans approximately one-eighth of a revolution and each impulse lasts for two segments due to the position of the two brushes.

In Fig. 2, the control circuits for the indication lamp I6 and the control magnet !8 are governed by the relays R! and R2 the same as in Fig. 1, and hence these devices are governed by the apparatus of Fig. 2 in response to rotation of the shaft I in exactly the same manner explained in connection with the apparatus of Fig. 1, except for the fact that the critical speed is relatively low.

Although I have herein shown and described only two forms of speed responsive apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I 1. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator including a. pair of successive segments each of a predetermined length, a contact brush operatively connected with said shaft for rotation therewith and adapted to successively engage said segments, a first and a second relay each provided with slow pick-up characteristics, a current source; a control circuit for each relay including a winding of the relay, a particular one of said segments, said brush and the current source for successively and periodically energizing said relays with current impulses of a given. polarity in response to rotation of said shaft; an indicating device, and an operating circuit for energizing said device including a front contact of each of the two relays in parallel.

2. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator including a pair of successive segments each of a predetermined length, a contact brush operatively connected with said shaft for rotation therewith and adapted to successively engage said segments, a first and a second relay each provided with slow pick-up characteristics, a current source; a control circuit for each relay including a winding of the relay, a particular one of said segments, said brush and the current source for periodically energizing each of said relays with impulses of a current of like polarity in response to rotation of said shaft and the durations of which impulses are dependent upon the speed of the shaft; an indicating device, and an operating circuit for said device including a front contact of each of the two relays in parallel.

3. Speed responsive apparatus comprising a shaft adapted to be rotated, a commutator including a plurality of successive segments each of a predetermined length, contact brush means operatively connected with said shaft for rotation therewith and adapted to successively engage said segments with engagement made with the next preceding segment before the receding segment is disengaged, a first and a second relay each provided with slow pick-up characteristics, a current source; a control circuit for each relay including a winding of the relay, the current source, said contact brush means and alternate segments of the commutator for successively energizing each of said relays with impulses of current in response to rotation of the shaft and the durations of which impulses are dependent upon the speed of the shaft; an indicating device, and an operating circuit of said device including a front contact of each of the two relays in parallel.

4. Speed responsive apparatus comprising a member adapted to be actuated through an operating cycle at different speeds, circuit controlling contact mechanism operatively connected with said member and including a plurality of contacts which are successively closed once for each cycle and which contacts are each closed during substantially equal portions of the cycle, said contacts made overlapping so that the preceding contact is closed before the receding contact is opened, a first and a second slow pick-up relay, a current source, a control circuit for each relay including a winding of the relay and alternate contacts of said mechanism as well as the current source, an indicating device, and an operating circuit for said device including a front contact of each of the two relays in parallel for energizing said device continuously when said member is stationary and deenergizing said device continuously when said member is actuated above a speed predetermined by the pick-up period of said relays.

5, Speed responsive apparatus comprising a member adapted to be actuated through an operating cycle at different speeds, circuit controlling contact mechanism operatively connected with said member and including a plurality of contacts which are successively operated once for each cycle and which contacts are each closed during substantially equal portions of the cycle, said contacts overlapping so that the preceding contact is closed before the receding contact is opened, a first and a second slow pick-up relay, a current source, an indicating device, an operating circuit for said device including a front contact of each of the two relays in parallel, and a control circuit for each of said relays including a winding of the relay and alternating contacts of said mechanism as well as the current source to pick up at least one of said relays for intermittently displaying the indicating device when said member is actuated at less than a speed predetermined by the pick-up period of the re lays.

6. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator including two oppositely disposed and overlapping segments, a contact brush operatively connected with said shaft for rotation therewith and adapted to successively engage said segments, a first and a second slow pick-up relay, a'slow release indicating device, an operating circuit for said device including a front contact of each of said two relays in parallel, a current source, means to connect one terminal of said source to one terminal of the winding of each relay in parallel and to connect the other terminal of the source to said brush, and means to connect the segments to the other terminal of the windings of said relays respectively to pick up at least one of the relays for actuating said indicating device continuously only When the shaft is rotated at less than a speed predetermined by the pick-up period of the relays.

'7. Speed responsive apparatus comprising a shaft adapted to be rotated at different speeds, a commutator provided with four spaced segments of substantially equal lengths, two angularly disposed contact brushes fixed on said shaft for engaging said segments in response to rotation of said shaft with engagement with at least one 1' segment whatever the position of the shaft, a first and a second slow pick-up relay, a slow release indicating device, an operating circuit for said device including a front contact of each of said two relays in parallel, a current source, means to connect one terminal of said source to one terminal of the Winding of each relay in parallel and to connect the other terminal of the source to both of said brushes, means to connect the otherterminal of the winding of the first relay to a first and a third one of said segments in parallel and to connect the other terminal of the winding of the second relay to a second and a fourth one of the segments in parallel to pick up at least one of the relays for actuating said indicating device continuously only when the shaft is rotated at less than a speed predetermined by the pick-up period of the relays.

8. Speed responsive apparatus comprising, a

member adapted to be actuated through an operating cycle at difierent speeds, circuit controlling contact mechanism operatively connected with said member and including a plurality of contacts which are successively closed once for each cycle and which contacts are each closed during substantially equal portions of the cycle, said contacts made overlapping so that a preceding contact is closed before the receding contact is opened, a first and a second slow pick-up relay, a current source, a control circuit for each relay including a winding of the relay and alternate contacts of said mechanism as well as the current source, an indicating lamp; and an operating circuit for said lamp including a front contact of each of the two relays in parallel for illuminating said lamp continuously when said member is stationary, for flashing the lamp when said member i actuated at a speed below a predetermined speed and for causing the lamp to remain dark when the member is actuated at a speed above said predetermined speed.

HERBERT L. BONE.

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