US2534984A

US2534984A - Rod brake

Info

Publication number: US2534984A
Application number: US702290A
Authority: US
Inventors: Don E Moran; Samuel F Jarvis
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1943-12-30
Filing date: 1946-10-09
Publication date: 1950-12-19
Anticipated expiration: 1967-12-19

Description

Dec. 19, 1950 D. E. MORAN ET AL 2,534,984

ROD BRAKE Original Filed Dec. 50, 194:5 2 Sheets-Sheet 1 asr Q M l 13 Q l i 30 Q 0 2/ IX m Y Q Q X l i t i l i (ID (11) Fig. 2.

65 4 F I Q g. 5+ 54 I II 4 O E :52 49 i 50 I 0 /5 I9 i J/ 44 53 47 'i-Z Inve ntor's: Don E. Moran, Samuel F. Jarvis.

198 W flf W ATTORNEY Dec. 19, 1950 D. E. MORAN ETAL ROD BRAKE 2 Sheets-Sheet 2 Original Filed Dec. 30, 1943 In Venbor's:

Don l'lMoran. Samuel F Jarvis ATTORNEY Patented Dec. 19, 1950 UNITED STATES BOD BRAKE Don E. Moran and Samuel F. Jarvis, Schenectady, N. Y., assignors to General Electric Company, a corporation of New York Original application December 30, 1943, Serial Divided and this application tober 9, 1946, Serial No. 702,290

3 Claims. 1 Our invention relates to plunger brakes, more particularly to self-actuated plunger brakes, and has for its object a reliable and inexpensive brake and stop apparatus which is free from displacement by heavy shocks.

This application is a division of our copending application Serial No. 516,260, filed December 30, 1943, for Electric Switch, and now issued as Patent 2,452,065.

As disclosed in the foregoing copending application, our invention is particularly useful as an armature brake and stop for electromagnetically operated switches. When electromagnetically operated switches are subjected to heavy shocks at the time the magnet is energized and the armature is in a normal attracted position against the stationary magnet frame, the shock has the effect of throwing the armature away from the magnet frame toward its unattracted position. This occurs against the magnetic force holding the armature in its attracted position. The type of shock contemplated is one that is applied to the body on which the switch is mounted, such as a shock caused by a nearby explosion. The effect of such a shock is applied from the supporting body to the magnet frame of the magnet and transmitted by the frame to the armature whereby the armature is thrown away against the magnetic force holding it in its attracted position.

In accordance with our invention, we prevent the transmission of the force of the shock from the magnet frame to the armature by bringing the armature to rest in its attracted position before it has moved far enough to engage the magnet frame. This we accomplish by providing stopping means for bringing the armature to rest in its attracted position before it engages the magnet frame. Moreover, our means for bringing the armature to rest does not have the rebound, characteristic referred to when subjected to a shock. In one form of our invention we provide friction braking means for engaging the armature as it approaches its attracted position and for applying an increased braking force as the armature continues its movement thereby to bring the armature to rest in spaced relation with the magnet frame.

. Our invention relates also to bus transfer switching means and, in accordance therewith, we provide electromagnetic means for normally operating the switching means together with manual means for deenergizing the electromagnetic means and for manually operating said transfer switching means.

For a more complete understanding of our inyention, reference should be had tov the'accompanying drawing, Fig. 1 of which is a bottom view looking up of a two-way electromagnetically operated switch embodying our invention; Fig. 2 is a View mainly in section taken along the line 22 of Fig. 3 looking in the direction of the arrows; Fig. 3 is an end view of the device shown in Fig. 1; Fig. 4 is an exploded view in perspective showing the various operating parts of the device; while Fig. 5 is a wiring diagram showing the application of our invention as a changeover switch for transferring the connections of a load from one supply source to another automatically in response to a predetermined decrease in the voltage of one supply source.

Referring to the drawings, we have shown our invention in one form as applied to a doublethrow bus transfer switching means comprising the two three-pole switches or contactors l0 and H (Figs. 4 and 5) which are shown diagrammatically. As shown in Fig. 5, these switches are controlled selectively to connect the load connections I2 to either a supply. source I3 or a supply source [4, the load and supply circuits being indicated as three-phase. The operating coils I5 and 16 for the two switches are controlled by a.

two-way selector switch H which in turn is operated by a control motor device l8 connected tothe supply source M. The control device It is responsive to the voltage of the source M to energize the coil I6 when the voltage of the source l4 drops to a predetermined minimum value thereby to disconnect the load circuit I 2 from the supply source l4, while at the same time the coil [5 is deenergized to' close the switch I0 and thereby connect the load circuit to the supply source 13. i

As shown, particularly in Fig. 4, the coils I5 and it are provided with stationary magnet frames l9 and 26 and with plunger armatures 2! and 22. These armatures are connected through

links

23 and 24 to a lever arm 25 secured at its center to one end of a pivot shaft 26. Connected to the ends of the arm 25 by means of suitable pin and slot connections are reciprocating

slider members

21 and 28, shown as cylindrical plungers which are mounted in suitable cylindrical guides in the support 29 for the mechanism. Thus, as shown in Fig. 2, the slider member 28 is slidably mounted in a cylindrical support 30.

For the operation of the switches I l] and H the

sliders

21 and 28 are provided with cutaway portions forming cam surfaces 3| and 32 with which cooperate

rollers

33 and 34 on the ends of

switch operating plungers

35 and 36 to which the switches l0 and II are directly connected. As

shown in Fig.4, the coil. I5 is deenergized while the coil I6 is energized and has moved the arm 25 clockwise, as seen in Fig. 4, and pulled downward its right-hand end. This action causes the cam surface 3| in moving upward to push the rod 35 toward the right, thereby opening the switch Hi. This movement of the rod 35 is transmitted through a lever 31 to the plunger 36 in the reverse direction so that the plunger 36 is moved toward the left whereby the switch II is closed. The lever 31 has a fixed pivot 38 at its center on a stationary support 38, and its ends are connected through pin and slot connections 40 and 4| to the two plungers.

It will be understood that when the coil IE is deenergized and the coil I is energized, the lever 25 is moved counterclockwise on its pivot shaft 26 thereby to open the switch I i and close the switch l0.

' For the'purpose of stopping the plunger armatures 2| and 22 before they engage and seat against their magnet frames l9 and 28, we have provided friction braking means associated with the two slider members 2'! and 28, comprising two pivoted braking and stop members 42 and 43 mounted adjacent their upper ends, as shown clearly in Fig. on fixed pivots 44 and :35. Re ferring particularly to Fig. 2, the pivoted braking member 43 is provided with a projection or extension 55 on its lower end extending toward the right into a recess in the lower end of the member 28. This recess or cutaway portion in the lower end of the member 28 provides a curved or tapered portion ti on its lower end presenting a cam surface or side wall to the laterally extending end projection 45' of the pivoted member, this surface lying in a plane at a small angle to the length of the member 28. Also, at the upper end of this portion 41 is a shoulder as forming an abutment lying in a plane at right angles to the length of the member 28.

Continuing with reference to Fig. 2, on the pivoted braking member 53, specifically on the portion at, are projections Q9 and 55 which engage respectively the plane surfaces on the shoulder 48 and the portion 4?. The projection is rigidly secured on the pivoted member while the projection 56 is yieldable and is in reality, as shown, a pin or plunger slid'ably mounted in a cylindrical recess 5! in the portien 55 and pressed outward by a helical spring 52. A screw 53, whose inner end projects into an annular groove 54 on the pin 5 limits the outward movement of the pin by the spring. Alsoyat its upper end at a point above and to the right of the pivot 45, the pivoted member has a projection in position to engage the side of member 28 when the member :13 is moved clockwise on its pivot 45. As seen in Fig. 2, the cylindrical g ide orsupport 30' for the member 28 is provided with aslot 56 through which extends the

projections

41 and 55 on the member 43.

As shown in Fig. 2, the member or plunger i's in its lowermost position in engagement with the projections :58 and 50. Its engagement first with the projection 59 has progressively turned the member 43 clockwise about its pivot t5- and thereby swung the projection 55 with a progreesively increasing force dependent upon the strength of the spring 55 against the side of the member 25. The pressure thus applied by the projection 5w progressively forces the member ZS toward the right, as seen in Fig. 2, tightly against the wall of its guide 39, thereby producing a frictional braking effect between the two as well as producing a frictional braking effect directly 4 between the projection 55 and its point of engagement with the member 28. Also the projection 49 when engaged during the final movement of the member 28 increases the frictional braking effect of the projection 55 and ultimately acts as a positive abutment stop for the member 28.

This brings the member 28 to rest in a position in which the lower end of the armature 22 is still in spaced relation with the magnet frame, as shown in Fig. -i. Therefore, shocks applied to the magnet frame or components of these shocks in an upward direction, as viewed in the drawing, are not applied to the plunger armature 22, the magnet frame 20 moving upward independently of the armature and relative thereto. Consequently, the shock has no effect in producing turning movement of the lever 25 and operation of the switches.

This upwardly directed shock will not throw the slidable member 21 nor the member 28 from its latched position, as shown in for the reason that the slidable member is held in this predetermined lowermost position by the relatively great friction between it and its guide 30, which friction is produced as previously (IE-- scribed by means of the pivoted looking or braking member 62 or 43. Also, it will be observed that because the various parts of the device that are rigidly connected together will be moved by a shock upward together, as well as in other di rections, then the pivot shaft 26 and the

plungers

35 and 36 will be moved upward together by the shock whereby the arm 25 is lifted, and with itlifted the plungers 2| and 22 at the same timethat the magnet frames are lifted by the shock. This action thus serves to maintain a predetermined air gap between the lower end of the particular plunger, at that time in its attracted pc sition, and the magnet frame.

It will be understood that the switches is and- I! may be of any suitable type, although they are shown diagrammatically in the drawing for the purpose of clarity.

As shown in Fig. 3, the operating mechanism thus far described is mounted on a supporting base or plate 5?, the magnet frames, armatures and

slidable members

21 and 28 being mounted below the plate 51 with the plunger-

s

35 and 38 extending upward through apertures in the plate and with the connecting lever 3'. mounted above the plate. This mechanism, as shown in Fig. 3, is preferably, as shown in Fig. 1, fitted into an open bottom casing 25. On the top of this casing are mounted the switches Kl and ii.

We have also provided manual means for operating the switches through the lever mechanism. This manual operating means comprises a knob 58 mounted on a shaft 59 which is sup-" ported on the top wall of the enclosing casing- 29, the shaft being biased outward from the" casing by a helical spring 60. Inside the cas in the end of the shaft 59 is provided with a transversely extending clutch member or blade:

6|. On the end of the pivot shaft 26 is a sham nel-shaped member 62 which is rigidly secured at its center to the shaft 26 and turns with the shaft. The channel member is wide enough, however, to provide a loose connection with the blade 6| which lies between the sides of the channel so that the shaft 25 is free to turn during theoperation of the switch from one position'tc the other without bringing either side of the channel member into engagement with the blade it; This assumes that the blade 61 is held .in cm intermediate position, as shown, by .meanscf the cup member 63 secured to the enclosing casing 29 and having pairs 63a of diametrically opposite notches in its edge. The shaft 59 is mounted on the cover in alignment with the pivot shaft 26.

When the knob 59 is depressed manually, the blade 61 is forced out of the central pair of notches and then the knob can be turned in the appropriate direction to bring the blade into engagement with the side walls of the channel member and operate the switch to the desired position. The knob can then be released to provide for movement of the shaft 59 outward by the spring and the locking of the blade 6| in the pair of notches corresponding to its position whereby the switch is locked in the position to which it has been operated. It will be understood that the side walls of the channel member are high enough to provide for this lateral movement of the blade 6| while the blade still remains between the side walls.

Also, to assure deenergization of the coils I5 and 15 when manual operation is resorted to, one end of the blade 6| is provided with a curved operating cam 64 which, when the knob 58 is in an intermediate position, bears on a switch rod 65 and forces it upward to hold closed the two switches 66 and 61. These switches, as shown in Fig. 5, are in the circuits of the operating coils. When the handle is turned from the mid position, the cam 64 moves to one side of the switch rod 65 whereby the switch is opened to open the circuits of the coils.

This manual operation of the switch by the knob 58 permits operation of it in the event that the voltage responsive device I 8 fails to operate the switches or in the event the operator desires to transfer the load from one circuit to the other, regardless of the voltage conditions.

In Fig. 1 the voltage responsive motor I8 is shown mounted in the casing in a position adjacent the switch operating mechanisms. It will be understood that this motor, provided with two

coils

68 and 69 connected across two phases of the supply source I 4, is connected permanently to the supply source l4 so as to be energized at all times. The rotor of the motor thereby under normal voltage conditions has a torque applied to it sufficient to return it to a predetermined position against the force applied by a biasing spring (not shown). When the voltage decreases to a predetermined minimum value, however, the torque applied to the rotor decreases and the spring thereupon turns the rotor back to its other predetermined position, shown in Fig. 5. in which the switching device I! is in position to energize the coil IE to open the switch II and deenergize the coil l5 to close the switch 10. As shown, the switching device I! is mounted on a pivot 10 and is provided with a forked portion H embracing an eccentric 12 operated by the motor.

While we have shown a particular embodiment of our invention, it will be understood, of course, that we do not wish to be limited thereto since many modifications may be made, and we therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. A plunger brake comprising an elongated plunger having a tapered cam surface on one side thereof, guiding means mounting said plunger for axial movement, a single elongated braking member pivotally mounted intermediate its ends and extending substantially parallel to the direction of movement of said plunger, a projection carried at one end of said braking member in position to be engaged by said tapered cam surface thereby to move said braking member progressively about its pivot, and braking means carried at the opposite end of said braking member and movable progressively by said pivotal movement into frictional braking engagement with a side of said plunger.

2. A plunger brake comprising, an elongated plunger having a tapered cam surface on one side thereof, guiding means mounting said plunger for axial reciprocating movement, a single elongated braking member extending along said one side of said plunger only and pivotally mounted intermediate its ends, and a spring pressed pin extending laterally from said braking member at one end thereof in position to be engaged by said tapered cam surface as said plunger approaches its limit of movement in one direction thereby to move said brakin member progressively about its pivot, the opposite end of said braking member being moved progressively by said pivotal movement into frictional braking engagement with the side of said plunger thereby to bring said plunger to rest.

3. A plunger brake comprising, an elongated plunger having a cut-away portion at the leading end thereof, said cut-away portion providing a tapered cam surface substantially parallel to the direction of movement of said plunger and an abutment having a surface substantially perpendicular to said cam surface, guiding means mounting said plunger for axial recipro eating movement, a single elongated braking member pivotally mounted intermediate its ends and extending substantially parallel to said direction of movement, and a lateral projection on the leadin end of said brakin member positioned to be engaged first by said tapered cam surface as said plunger approaches its limit of movement and later by said abutment to bring said plunger to rest, said cam surface when engaging said projection rotating said braking member progressively about its pivot thereby to bring the opposite end of said braking member progressively into frictional braking engagement with the side of said plunger.

DON E. MORAN. SAMUEL F. JARVIS.

REFERENCES CITED The following references are of record in the rile of this patent:

UNITED STATES PATENTS Number Name Date 933,140 Tuttle Sept. 7, 1909 1,714,498 Danner May 28, 1929 1,726,012 Bilz Aug. 27, 1929 1,818,832 Walle Aug. 11, 1931 1,827,188 Burgess Oct. 13. 1931 1,944,116 Stratman Jan. 16, 1934 2,452,065 Moran et al Oct. 26, 1948 FOREIGN PATENTS Number Country Date 359,810 Germany June 14,- 1921 356,801 France Oct. 18, 1905 506,896 France Aug. 31, 1920 733,583 France Oct. 7, 1932 Certificate of Correction Patent No. 2,534,984 December 19,1950

DON E. MORAN ET AL. 7

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3,

lines

32 and 33, strike out the Words curved or tapered and insert the same in line 34 after a;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oifice.

Signed and sealed this 1st day of May, A. D. 1951.

THOMAS F. MURPHY,

Assistant Gammz'asz'oner of Patents.