US2098032A - Contact mechanism - Google Patents

Description

Nov. 2, 1937. J. A. FAVRE 2,098,032.

conmcw MECHANISM Filed March 23, 1937 Fig.3

Inventor is Attovnev.

Patented Nov. 2, 1937 PATENT OFFICE CONTACT MECHANISM John A. Favre, Rutledge, Pa., assignor General Electric Company, a corporation of New York Application March 2a, 1937, Serial No. 132,513

16 Claims. -(c1. zoo-153) My invention relates to improvements in contact mechanisms, and more particularly to contactmechanismsforelectroresponsivedevices,such as relays and the like, and an object of my inven- 5 tion is to provide an improved contact mechanism whereby to eliminate rebound; that is, separation of the contacts one or more times after their first engagement. This and otherobjects of my invention will appear in more detail hereinafter.

10 In electroresponsive devices, such as quick-acting sensitive relays, which respond to fault conditions for the protection of electric circuits, the relatively movable co-operating contacts of the relay must engage quickly and stay engaged long 5 enough to fulfill the protective relay function. But since at least one of the contacts must be quickly actuated, and when once moving it tends so to continue, considerable kinetic energy must be suitably disposed of when the contacts en- 20 gage. Otherwise, the sudden stopping of the movable contacts will result in rebound or contact bouncing; that is, a separation of the contacts called memory action, wherein, although initially there may be ample force to effect contact closure, such force may so rapidly diminish as to be sufflcient merely to maintain contact closure if the bouncing is not present.

I 35 In accordance withmy invention, I provide means whereby the kinetic energy of the moving contact mass is. substantially instantaneously transferred or imparted to other movable means which are arranged to dissipate the energy they 40 receivewithout such reaction on the closing contacts as to produce separation thereof after engagement. Further in accordance with my invention, I may provide means whereby in the case of excessive forces acting on the movable 45 contact structure, such forces may be allowed, in

part at least, to expand themselves without having the contact structure act as an abutment against which these forces are solely exerted. While my invention is particularly adapted for use 50 in electroresponsive devices such as relays, its application obviously is not limited to devices wherein the contact mechanism is actuated only by electromagnetic means. In other words, my invention is generally applicable to contact mecha- 55 nisms regardless of the character of the actuating means, if the necessity for eliminating contact bouncing is present.

This application is a continuation in part of my copending application Serial No. 50,673,'filed November 20, 1935, for contact mechanism, the subject matter in said prior application being incorporated in this application together with certain additional subject matter.

My invention will be better understood from the following description when considered in connection with the accompanying sheet of drawings, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. 1 is a plan view of an embodiment of my invention; Fig. 2 is a plan view of a modification of the embodiment of my invention shown in Fig. 1; Fig. 3 is a front elevation, partly in section, of the embodiment of my invention shown in Fig. 2; Fig. 4 is a partial side elevation, partly in section, looking from the right of Figs. 2 and 3; Fig. 5 is a vertical partly sectional elevation of another embodiment of my invention; Fig. 6 is an exploded perspective view of the embodiment of my inventionshown in Fig. 5; and Fig. 7 is a vertical elevation of a mounting suitable for use with devices embodying my invention.

In the embodiment of my invention shown in Fig. 1, I have illustrated a contact mechanism including relatively movable co-operating contacts l0 and i l,of which contact It! may be termed the movable contact and contact i I the fixed contact. The contact!!! is illustrated as mounted on an arm or crank H which is movable by an op erating member, such as a shaft l3. Obviously, an actuating force may be applied to turn the shaft I 3 clockwise to produce contact-engagement, by any suitable means, such as electromagnetic, electrostatic, pressure actuated, thermally operated, or otherwise, examples of all of which are well known to the art. The contact I I may be mounted on an arm such as a leaf spring I4, which maybe secured to an adjustably positioned base support I 5, angularly adjustable as shown in Fig. '1, whereby to provide for contact adjustments such as contact gap setting. In any given position, the motion of the spring it maybe limited by a suitable stop means, such as an adjustably positioned arm l6 provided with a motion limiting aperture ll.

In order to prevent rebound of the contacts i0 and i l on engagement thereof, I provide movable means for substantially instantaneously taking over or receiving the kinetic energy of the contacts in and i! when they engage, and I then subsequently dissipating such transferred energy. As shown in Fig. 1, this means includes a rollable mass, such as a ball I8, which is normally in engagement with the side of the contact opposite its contact-engaging surface.

The weight of the ball I8 is suitably proportioned to the mass of the moving assembly. In order to maintain the ball I8 in its correct position, and also to dissipate the energy imparted to the ball, it may be mounted in a tubular chamber l9, whose outward opening is less than the diameter of the ball and whose diameter is sufiiciently close'to the diameter of the ball to delay the motion of the ball in both directions.

Thus, the energy of the ball is dissipated on the inward movement as air escapes from the back of the ball around its edge, and its outward movement is similarly delayed so that the ball does not return quickly-enough to separate the contacts when it re-engages contact II on its return to the lower end of the tubular chamber I9. Obviously, this may be inclined at such an angle as to insure the desired return based on the'dash-pot action of the ball in both its in. ward and outward movements.

In order to provide for contact adjustment, the tubular chamber I9 is preferably adjustably supported by any suitable means such as an arm 20 which, as shown in Fig. 1, is secured to an angularly adjustable base support 2|. While I have shown the movable energy receiving body as a ball, it will be obvious that any suitable rollable mass may be employed. Also as shown, the contact mechanism is of the single throw type, but it will be obvious that the mechanism shown to the left of the movable contact l0 may be duplicated on the right for double throw action with another contact ill on the arm i2.

Assuming the contacts i0 and H positioned as shown in Fig. 1 and that the contact I!) is suddenly actuated to engage the contact II, the kinetic energy at the engagement will be imparted directly through the contact II to the ball l8 so that the contacts l0 and il may remain in engagement while the ball l8 rolls inwardly in its tubular channel against the dashpot action of the air escaping around its edge. At the end of its travel in the tubular chamber IS, the ball will start rolling outwardly again under the dashpot action of the infiowing air so that it comes to rest at the end of the tube without jarring the contacts to an extent sumcient to cause separation thereof.

In the embodiment of my invention illustrated in Figs. 2, 3, and 4, instead of having the kinetic energy of the contacts transferred directly to the ball I8, I provide a second movable mass such as a ball 22, which is suitably cushioned in an outer compartmentof the tubular chamber l9. For this purpose, I may provide, as shown in Fig. 4, a buffer pad, such as a felt washer 23, which is held in place against a shoulder or inner ring 24 of the chamber l9. Thus, normally the fixed contact I rests against the ball 22, which may just be touching the felt washer 23. When the contacts l0 and H engage, most of the energy of the impact is transferred through the ball 22 to the freely moving ball l8 but someis ,absorbed by the buifer 23 as it is compressed. The ball |8 may also have a cushioning buffer 25 to take up its energy so that it-does not violently rebound from the closed end of the chamber i9. When the ball l8 slowly rolls down the inclined chamber, it meets the ball 22, which is being slowly returned as the tween the shaft buffer 23 expands. Consequently, the meeting of the balls is so gradual as to effect no contact separation. This feature is of particular value in devices of the so-called memory action type, where the forces necessary'to move the contacts to engagement rapidly decrease to a value just 1 amount of friction between the ball and the contact. Thus the contact may be recessed on its rear side, as shown more clearly in Fig. 4' to provide a large annular ring or seat engagement with the ball. Then while the ball 22 is rolling back to its normal position, some of its energy is consumed in friction against the seat on contact ii.

In Figs. 3 and 4, I have indicated only in elevation an electromagnetic means 28 of the induction type for actuating the shaft i3, since devices of this type are well known to the art. I have also shown a coiled lead-in 21 from the terminal post 28 to the movable contact Hi. If desired this lead-in may also be of such a resilient character as to provide suitable bias for maintaining the contact l0 normally in a predetermined position.

Also in Fig. 3 and likewise in Fig. 2, I have illustrated further means for assisting in the prevention of rebound by a slip connection bel3 and the contact i0. As shown in Figs. 2 and 3, there is a slip clutch comprising a lower abutment 29 and an upper abutment 30, both secured to the shaft i3 so as to rotate therewith, resilient means, such as a spring 3|, whose compression may be varied by the position of the upper abutment, which may be a nut threaded on the shaft, as shown, and relatively rotatable elements providing the slip feature. As shown, and beginning from the top and going down, these elements are: two washers 32 and 33, between which the spring 3| is confined and which are rotatable with the shaft |3, a felt washer 34, a metallic washer 35, an annular ring 36, which seats on the upper side of the arm I2 of the moving contact In and over the upper end of a hub member 31 to which the .contact arm is pinned, a seal-in arm 38 which is also pinned to the hub 31, and a felt washer 39.

The seal-in arm 38- and the movable contact arm |2 are thus rotatable together, but the shaft i3 may rotate independently of both by reason of slip between the relatively rotatable parts such for example as the felt washer 34 and the metal washers 33 and 35. The seal-in arm 38 carries an armature 40 which engages the poles of a seal-in electromagnet 4|. This may be energized on closure of the contacts I!) and II by including its winding in the circuit they energize, as is well known to the art.

In order to avoid difficulties due to the natural vibration period of the resilient contact arm i4. shown in Fig. l, the contact may be mounted on a rigid arm M; as shown in Figs. 2 and 3.

This arm is pivotally mounted at 42. In this case, a stop 43 may be provided to limit movement of the contact toward its contact l0.

-In order to avoid any possibility of electrical contact between the lead-in 21 and the clutch spring 3|, an insulating housing 44 in the form of a cylindrical shell may be provided around the spring.

In the embodimentof my invention illustrated in Figs. 5, 6, and 7, the chamber or barrel l9 houses a closely fitting ball IB which normally rests against a diaphragm'45. This dia. phragm is retained against the open end of the barrel by a flanged collar 46 suitably secured to the barrel. In order to absorb contact vibrations when the force actuating the movable contact is small and also to prevent contact chattering due to slight vibrations external to the relay, the fixed contact H may be mounted on a spiral spring 41 which is held in place by. the collar 46 and spaced from the diaphragm 45 by a ring 48 so as to permit some .slight movement of the contact I I before effecting movement of the ball I8. The diaphragm 45, in addition to acting as a wall for holding the ball in the lower end of the barrel, also keeps out. foreign matter such as dust and the like. This is important because of the close fit between the ball and the barrel for the desired dash-pot or energy dissipating action. In

order to avoid difficulties from rust, corrosion, and the like, the ball I8 may be made of stainless steel and the barrel E9 of brass.

For simplification in mounting, the barrel 19 may be threaded as shown to screw into a nut,

Assuming the parts positioned as shown in Fig.

5," then if a weak forceactuates the contact Hi to engage the contact H, the relatively weak.

spiral spring 61 will substantially absorb thecontact impact without causing any bouncing. However, if the force actuating'the'moving contact H) is large, this contact will be caused to impinge against the diaphragm 55, thereby causing the shock to be transmitted to the ball id. The resultant transfer of energy to the ball causes movement thereof upwardly in the barrel and the energy of such motion is dissipated by the dash-pot action of the ball movement in the barrel. When the ball has reached the end of its upper movement in the barrel, it rolls back gradually under dash-pot action and Ecomes to rest against the diaphragm without causing a bouncing or separation of the contacts.

While I have shown and described my invenv tion in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

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

1. A contact. mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, and means for preventing rebound of said contacts on' engagement thereof including a housing and a rollable member movable in said housing with a dash-pot effect for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof and subsequently dissipating said energy.

2. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other.

contact, 'means for preventing rebound of said contacts on engagement thereof including a housing and a rollable member movable in said housing with a dash-pot effect for substantially said contacts on engagement thereof including a tubular housing and a ball within said housing closely fitting the bore thereof for substantially instantaneously taking. over the kinetic energy of said contacts on engagement thereof, and subsequently dissipating said energy.

4. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, and. means for preventing rebound of said contacts 'on engagement thereof including a housing and a reliable member within said housing movable therein with a dash-pot effect and mounted in the path of movement of said con tacts for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof and subsequently dissipating said energy.

5. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, means for preventing rebound of said contacts on engagement thereof including a housing and a rollable member within said housing movable therein with a dash-pot effect and mounted in the path of movement of said contacts for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof and subsequently dissipating said energy, and a slip clutch between said actuating means and said one of said contacts.

6. A contact mechanism including relatively movable co-operating contacts, means for actuat ing one of said contacts'to engage the other contact, means for preventing rebound of said contacts on engagement thereof including a rollable member in the path of movement of said contacts for substantially instantaneously taking over the kinetic energy of the contacts on engagement thereofyand means for retarding the rolling action of said member whereby to dissipate the energy transferred thereto.

,7. A contact mechanism including relatively and a.restricted tubular channel housing said ball for retarding the rolling action thereof whereby to dissipate the energy transferred thereto.

8. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, means for preventing rebound of said contacts on engagement thereof including a first 'movable means having relatively limited movement for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof, means for. limiting the movement of said first movable means, a second movable means having a larger movement for taking over the kinetic energy of said fir'st movable means, and means for dissipating the energy transferred to said second movable means.

9. A contact mechanism including relatively said first rollable member and engageable thereby to take over the remainder of the kinetic energy thereof, and means for dissipating the energy transferred to said second rollable member.

iii

10. A contact mechanism including relatively movable co-operating contacts, means for actu--v atlng one of said contacts to engage the other contact, means for preventing rebound of said contacts on engagement thereof including a first ball in the path of movement of said contacts for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof, a. cushion for limiting the-movement of said ball and absorbing some of the energy imparted thereto, a second ball in the path of movement of said first ball for taking over the remainder of the kinetic energy thereof on engagement of said balls, and a restricted tubular channel for retarding the rollingaction of said second ball whereby to dissipate the energy transferred to the second ball.

11. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, means for preventing rebound of said contacts on engagement thereof including a first ball in the path of movement of said contacts for substantially instantaneously taking over the kinetic energy of the contacts on engagement thereof, an annular seat on said other contact for engagement with said ball, a buffer ring for limiting the movement of said first ball and absorbing a part of the energy imparted thereto, a second ball in the path of movement of said first ball for taking over the remainder of the'kinetic energy thereof on engagement of said balls, and a restricted tubular channel for retarding the rolling action of said second ball Wherebyto dissipate the energy transferredthereto.

' 12. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, means for preventing rebound of said contacts on engagement thereof including movable means for substantially instantaneously taking over the kinetic energy of said contacts on engagement thereof, means for providing frictional engagement between said movable means and said other contact, and means for subsequently absorbing and dissipating the energy transferred to said movable means including a housing and a rollable member within said housing movable therein with a dash-pot efiect.

, 13. A contact mechanism including relatively 'movable co-operating contacts, -means for actuating one of said contacts to engage the other contact, and means for preventing rebound of said contacts on engagement thereof including a tubular housing, a diaphragm at one end of the housing mounted in the path of movement of said contacts to receive the impact of contact engagement, and a ball within said housing closely fitting the bore thereof and normally resting against said diaphragm to receive therefrom the kinetic energy of said contacts on engagement thereof and subsequently to dissipate said energy.

14. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, and means for preventing rebound of saidcontacts on engagement thereof including a tubular housing resiliently supporting one of said contacts at one end of the housing, a diaphragm at said end of the housing intermediate the end and said resiliently supported contact and adjacent said contact for receiving the impact of contact engagement, and a ball within said housing closely fitting the bore thereof and normally resting against said diaphragm to receive therefrom thekinetic energy of said contacts on engagement thereof and subsequently to dissipate said energy 15. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, and means for preventing rebound of said contacts on engagement thereof including a, housing, a diaphragmat one end of the housing mounted in the path of movement of said contacts to receive the impact of contact engagement, and a rollable member within said housing movable therein with a dash-pot effect and normally resting against said diaphragm to receive therefrom the kinetic energy of said contacts on engagement thereof and subsequently to dissipate said energy.

16. A contact mechanism including relatively movable co-operating contacts, means for actuating one of said contacts to engage the other contact, and means for preventing rebound of said contacts on engagement thereof including a tubular housing, a diaphragm at one end of the housing mounted in the path of movement of said contacts to receive the impact of contact engagement, means for resiliently supporting one of said contacts adjacent said diaphragm but normally spaced therefrom, and a ball within said housing closely fitting the bore thereof and normally resting against said diaphragm to receive therefrom the kinetic energy of said contacts on engagement thereof and subsequently to dissipate said energy.

JOHN A. FAVRE.

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