US3185790A - Motor operated power transfer switch - Google Patents

Description

May 19.65. P. G. SALERNO 3,185,790

MOTOR OPERATED POWER TRANSFER SWITCH Filed June 5, 1963 s Sheets-Sheet 1 Inventor May 25, 1965 P. G. SALERNO MOTOR OPERATED POWER TRANSFER SWITCH 5 Sheets-Sheet 2 Filed June 5, 1963 P J [mg entanaa a r 0 4/ 2 O.\\ I

y 25, 1965 P. G. SALERNO 3,185,790

- MOTOR OPERATED POWER TRANSFER SWITCH Filed June 5, 1963 3 Sheets-Sheet 3 M if.

United States Patent 3,185 796 MOTOR OPERATED POW ER TRANSFER SWITI I Paul G. Salerno, Glen View, 11L, assignor to Vapor Corporation, Chicago, Ill., a corporation of Delaware Filed June 5, 1963, Ser. No. 285,747 4 Claims. (Cl. MPG-92) The present invention relates to a power transfer switch. The invention relates more particularly to a power transfer switch utilizing an electric motor for the switch- 'ing operation, in which the operating parts, the contacts of the switch as Well as the operating motor, are enclosed within a hermetically sealed casing, with contact terminals projecting through the casing for appropriate connection in circuit.

A broad object of the invention is to provide a power transfer switch of the foregoing character which is of extreme simplicity and consequent great reliability.

Another object is to provide a switch of the foregoing character which is of compact design and utilizes an unusually small motor because of its compactness.

Another object is to provide a switch of the character indicated having a shorter transfer time than usual.

A further object is to provide a switch of the character indicated in which no power from the motor is required to hold the switch in either of opposite limit positions, the switch being retained in its limit positions by a mechanical over-center device.

Another object of the invention is to provide a power transfer switch of the character noted in which a mechanical snap action is utilized in the switching operation, thereby requiring only a low minimum motor operating voltage.

A further object is to provide a switch in which a high contact force is established between the terminal contacts and a wiping action is established between the contacts in the closing operation, whereby only a low millivolt drop is encountered through the contacts;

Still another object is to provide a switch incorporating yieldable biasing means for accommodating overrun of the contact closing means, this same yieldablc biasing means being of strength substantially greater than the weight of the contacts and their holder, whereby to eliminate bounce and vibration of the contacts under surrounding vibration conditions.

Another object is to provide a switch having a movable contact carriage which moves between opposite limit positions in the switching operations, in which the parts supported and carried by the contact carriage are distributed about its pivot axis, whereby to provide a balanced mass, and greater etliciency in operation.

Other objects and advantages of the invention will appear from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a top view of the switch with the cover element of the enclosing casing removed, and veiwed approximately on line 1-1 of FIG. 2;

FIG. 2 is a sectional view, on an enlarged scale, taken approximately on line 2-2 of FIG. 1;

FIG. 3 is an exploded and distorted isometric view of the principal operating parts of the switch, certain elements being shown semi-diagrammatically, and certain elements being shown in section;

FIG. 4 is a small scale view similar to FIG. 1, but taken at a plane slightly lower than the plane of FIG. 1, this view showing the over-center means in a first limit position;

FIG. 5 is a view similar to FIG. 4, but showing the overcenter means in an intermediate position;

FIG. 6 is a view similar to FIGS. 4 and 5, but showing the over-center means in the opposite limit position;

FIG. 7 is an axial view of a portion of the representa- 3,185,790 Patented May 25, I365 tion of FIG. 3, showing the contact carriage in switchopen position;

FIG. 8 is a view similar to FIG. 7, but showing the contacts at the moment of engagement in the closing operation;

FIG. 9 is a. view similar to FIGS. 7 and 8, showing the contacts engaged, but with the contact carriage in a more advanced position and the yieldable biasing means slightly compressed;

FIG. 10 is a View similar to FIGS. 7, 8 and 9, but with the contacts in a fully engaged position, and with the yieldable biasing means fully compressed;

FIG. 11 is a detail view, partially in prespective, and

taken substantially at line 11-41 of FIG. 7, showing the contacts in open position;

FIG. 12 is a view similar to FIG. 11, but with the contacts in engagement, and with the yieldable biasing means fully extended;

FIG. 13 is a view similar to FIGS. 11 and 12, but with the contacts in full force engagement, and with the yieldable means fully compressed;

FIG. 14 is a View similar to FIG. 7, but showing a double throw arrangement; and

FIG. 15 is a diagram of the switch contacts and c011- tactors utilized in the switch.

Referring in detail to the drawings, attention is directed first to FIGS. 1, 2 and 3 showing the switch embodying the features of the present invention substantially in its entirety. The switch structure illustrated includes a hermeticaliy sealed casing it) entirely enclosing all of the operating parts of the switch and preventing the propagation of sparks generated therein in the switching operation. The connector elements 22 are incorporated in the casing, with extensions to the exterior, in a known manner.

Mounted in the casing is a top gear plate 24 and a bottom plate as, together constituting frame means or supporting means supporting substantially the remaining portions of the switch. The gear plate 24 may be provided with strengthening ribs 23 radiating from a hub portion 36 having an interior space 31 opening through one side at 32.

A contact carriage 34 is disposed concentrically in the casing and mounted for rocking movement in a manner to be described in detail hereinbelow. This contact carriage is preferably cylindrical in shape, defining a cavity 36 in which a motor 38 utilized for performing the switching operations is friction-fitted for rocking movement therewith, the motor engaging a rearwardly or downwardly facing interior shoulder 40, and secured in the cavity by compound material 42. At the lower end of the contact carriage is a plate 44 suitably secured therein and having an axial bearing extension 46 supported in a bearing opening 48 in the bottom plate 26.

The drive shaft of the motor 38 is indicated at 50, and is connected, by means of a flexible coupling 52, to another shaft 54 mounted in suitable bearings 58 in the hub portion 301 of the gear plate 24. A pinion 5a is secured to the shaft 54 and meshes with a gear sector 60 of a movable member 62 forming a portion of a mechanical overcenter device indicated in its entirety at 64, the gear sector 69 projecting through the side opening 32 into the interior space 31.

The gear plate 24 has an extension 24a which extends into the opening of an annular plate 66. Extension 24a is coaxial with the bearing extension 46 at the lower end of the contact carriage. These extensions support the contact carriage and thus the motor for rocking movements in opposite directions about the axis of the extensions 24a and 46 in the switching operations as referred to hereinbelow.

Mounted on the upper end of the contact carriage 34,

I? and movable therewith, is the annular plate 66, secured thereto as by cap screws 63 one of which is shown in FIG. 2. This plate has a radial arm "it? (FIGS. 2 and 3) in which is mounted a post 72 extending through a clearance hole '74 in the gear plate 24, and into the confines of the movable member 62 of the over-center means 64.

The movable member 62 has a hub portion '76 trunnioned on a stub shaft 78 fixed in the gear plate 24 and extending thereabove. This movable member includes a pair of angularly spaced arms 89 merging into the gear sector 69. This gear sector, as will be noted, is on the order of 60 angular dimension, and it has a range of movement in the neighborhood of 45 in its operation described hereinbelow. The side arms titl are provided with recesses 84 to facilitate engagement with opposite limit posts 36 adjacent the marginal edges of the switch casing. A compression spring 83 is biased between the contact carriage post 72 which, as noted above, extends into the space between the arms 8% and the gear sector 6t at a point on the latter indicated at 99, preferably adjacent the center thereof.

Attention is directed again to the contact carriage 34 (FIG. 3) and to the following description thereof concerning the switching operation. The contact carriage 34 includes arms 92 extending therefrom in opposite lateral directions with a substantial radial component. Mounted on and movable with these arms are contacts 94- which engage stationary contacts 96. The movable contacts 94 are incorporated in a contact assembly 93 described hereinbelow, while the contacts 96 are mounted on stationary means Tilt), shown diagrammatically in FIG. 3. This supporting means Ttitl may take any of various forms, such, for example, as a cylindrical member (FIG. 2) surrounding the contact carriage 34 and supported by the top gear plate 24 and bottom plate 26 in any suitable manner, such as indicated at the points Till. The supporting means 1%, or contact housing (FIG. 2) supports a plurality of blocks MP2, on which the contacts 96 are mounted, there being four on each side, only those on one side being shown in FIG. 2. FIG. 2 also shows two arms 92 and assemblies 98 thereon, each bearing two of the contacts 94. For simplicity in illustration, a portion of the elements of FIG. 2 have been omitted from FIG. 3, the contact carriage 34 in FIG. 3 being of sub stantially half its full length and being shown as if taken at line 33 of FIG. 2.

Each contact assembly 98, herein sometimes designated a contactor for convenience, includes a plate 196 supporting the movable contacts 94 and secured to the corresponding arm Q2 by means of a contact holder 1G8. This contact holder 10$ is preferably in the form of a shaped metal piece having hooks 110 straddling the side edges of the plate 106 and engaging the under surface thereof, and hooks 112 extending transversely to the hooks lltl straddling the side edge of the arm 92.

interposed between the plate 195 and the arm 92 is a stainless steel leaf spring 114 (FIGS. 11-13) having a central bowed portion 116 engaging the arm Q2 and fiat end surfaces 118 engaging the plate 106. The plate 1% has sliding engagement with the hooks 1m to enable it to move toward and from the arm 92 in the switch closing and opening movements. When the contact holder is in switch-open position, with the contacts 94 and 96 separated, the leaf spring 116 biases the plate 166 and the contacts 9 thereon away from the arm 92, and when the contact holder moves to switch closing position (counterclockwise, FIGS. 7-10) with consequent engagement between the contacts 94- and 96, the leaf spring 116 yields under the continued movement of the arm 92, as represented by the relative positions illustrated in FIGS. 12 and 13. Certain specific characteristics of the contacts and leaf spring will be referred to again hereinbelow.

The blocks 16 2 bearing the stationary contacts 9 5 are provided with terminal extensions 12% adapted for connection with connector el ments in a known manner.

The electric motor 38 is providid with connecting leads 122 which, in order to eliminate flexing connections, are contained within the contact carriage 34 and connected with circuit connections leading through the contact carriage to appropriate ones of the contacts 94-.

Assuming a starting position of the contact carriage 34 as represented in FIG. 3, with the switch in open position, the motor 38, upon energization thereof, rotates the drive shaft 56 thereof in a clockwise direction as viewed in FIG. 3 from the lower right. This rotation is represented by the arrow 124 in FIG. 4, the pinion S6 rotating counterclockwise as viewed in the latter figure. This pinion meshing with the gear sector 60 rotates or rocks the latter in clockwise direction as indicated by the arrow 126. The movable member 62 therefore rocks from one limit position shown in FIG. 4 toward the opposite limit position shown in FIG. 6, and in the course of this movement, as it reaches the approximate position shown in FIG. 5, the contact carriage post 72 swings over center represented by the line 123, carrying the contact carriage with it, thus moving the contacts 94 into engagement with the stationary contacts 96, closing the switch. The switch ing operation also interrupts the driving current to the motor 38, but it remains established until the overcenter means becomes effective, when the compression spring 83 continues to move the member 62 in clockwise direction (FIGS. 3-6) until it reaches its opposite limit position as limited by the corresponding limit post 86. This continued movement of the member 62 continues to rotate the drive shaft of the motor until the member 62 reaches the opposite limit position.

The movement of the contact carriage 34 is a snap action movement, the contacts remaining open until the post 72 snaps past the line 128 and then abruptly closing.

In the switch opening operation, the motor is driven in the opposite direction, and the various parts move toward and assume their opposite positions in the manner described above in connection with the switch closing operation. In the switch opening operation also, the contact carriage 34 operates through a snap action movement.

The illustrations of FIGS. 2 and 3 indicate a single throw switch, but it will be understood that the construction is readily adaptable to a double throw switch. Such a switch is indicated in FIG. 14, where the arm 92 is provided with a contact assembly 98 on each of opposite sides, and a second set of contacts 96 is provided for engagement by the corresponding movable contacts 94 when the contact carriage 34 is in opposite position, or that corresponding to that indicated in FIG. 3. FIG. 15 includes a diagram of contacts adapted for incorporation in the switch described above, that is, three pairs of stationary contacts 96 are provided in a single pole arrangement; also included are motor reversing contacts 96a and 96b. The opposed contacts 96a and 96b are utilized for reversing the voltage of the motor 38 for driving the latter in each of opposite directions in alternate operations of the switch. This is accomplished by application of electrical power to the proper terminals denoted in the lower left corner of FIG. 15.

Attention is directed to FIGS. 7 to 13 for a representation of the specific contact-closing and contact-opening movements. The plate 1% as noted above is mounted on the arm 92 for movement toward and from the arm. This plate is also mounted for limited angular movement relative to the direction of its switch closing movement. As shown best in FIG. 7, the contact assembly 98 is disposed at a substantial angle to the closing movement thereof, the dot-dash line 13%) indicating the direction of closing movement, and the line 132 the angular position of the contact assembly 98. After engagement of the contacts in the closing movement of the switch, the control assembly moves angularly toward the direction of movement and causes a wiping action between the movable and stationary contacts. This action is indicated in FIG. 8 where the contacts are shown in the initial step of engagement and the angular distance between the lines 130 and 132 is slightly reduced. As the switch closing operation continues, as represented in FIG. 9, the leaf spring 116 is partially compressed, and the movable contacts 94 have moved angularly to a position in which they extend more nearly in the direction of closing movement. In the final position represented in FIG. 10, in which the switch is in full-closed position, the contacts are moved to a position in which they extend substantially in the direction of closing movement. The Wiping action caused by this movement of the movable contacts greatly increases the electrical contact engagement between the contacts. This wiping action and the compression of the leaf spring 116 described above are accomplished in the latter portion of the movement of the contact carriage 34 through the action of the compression spring 88, rather than the driving force of the motor. The snap action of the over-center device overtakes the driving force of the motor in the latter portion of the movement and therefore the torque required of the motor for the switching operation is at a minimum, being merely that necessary to move the movable member 62 to over-center position, and is not utilized for directly moving the contact carriage in the switch opening and switch closing movements.

The force of the compression spring 116 is preferably many times greater than the weight of the plate 106 and the movable contacts 94 thereon, so as to prevent vibration or chattering of the plate 106 in surrounding vibration conditions. Preferably, this force of the leaf spring relative to the weight of the movable element is on the order of 80 to 1.

While I have disclosed herein a certain preferred form of the invention, it will be understood that changes may be made therein within the scope of the appended claims.

I claim:

1. A switch of the character disclosed comprising, in combination, mounting means, a set of stationary contacts supported by said mounting means, a contact carriage having contactor means thereon and movable between opposite positions in which the contactor means is respectively in and out of electrical engagement with said contacts, a mechanical overcenter mechanism including a member movable between opposite limit positions, said over-center mechanism also including a compression spring reacting between said movable member and contact carriage, a reversible electric motor having driving connection with said movable member and operable for moving the latter to over-center position in each direction toward its opposite limit position, said movable member being operable, acting through said compression spring for moving said contact carriage to its opposite position in response to its own movement to over-center position,

said contact carriage being rockable about a central longitudinal axis, the stationary contacts including contacts on radially opposite sides of the contact carriage and the contactor means including movable contacts on each of radially opposite sides of the contact carriage positioned for engaging respective ones of said stationary contacts, whereby the contact carriage is balanced by distribution of mass symmetrically around said axis, and said motor being mounted within and carried by said contact carriage.

2. A switch structure comprising, in combination, supporting means, a contact carriage mounted in the supporting means for rocking movement about a central longitudinal axis to opposite limit positions, stationary contacts mounted on said supporting means on each of radially opposite sides of said contact carriage, contactors mounted on said contact carriage on radially opposite sides thereof and movable into and out of engagement with respective stationary contacts in response to movement of said contact carriage to its opposite positions, said contact carriage including a central cavity, a reversible motor mounted in said cavity and carried by said contact carriage, a mechanical over-center device including a movable member pivoted on said supporting means and movable between opposite limit positions, said movable member having a gear sector on a swinging end, said contact carriage having an eccentric element extending axially to a position within the confines of said movable member, said extension being movable, in response to rocking movement of said contact carriage, to respective positions on opposite sides of a line passing through the axis of movement of said movable member and bisecting the angle of movement thereof, a compression spring biased between said extension and said movable member at a point on the latter adjacent the angular center thereof, and a pinion driven by said motor, concentric with said central longitudinal axis, and in mesh with said gear sector.

3. The invention set out in claim 2 in which circuit for controlling said motors is provided, and it includes connections for said motor fixed to said contact carriage and connected through certain of said contacts and contactors.

4. The invention set out in claim 2 in which all of the stated elements are enclosed in a hermetically sealed casing, and circuit elements are included, connected with said contacts and leading through the wall of said casing.

References Cited by the Examiner UNITED STATES PATENTS 560,766 5/96 Van Vleck 200-92 2,116,075 5/3 8 Lenhart 200-92 2,924,685 2/60 Burch 200--104 BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner.

Claims (1)

1. A SWITCH OF THE CHARACTER DISCLOSED COMPRISING, IN COMBINATION, MOUNTING MEANS, A SET OF STATIONARY CONTACTS SUPPORTED BY SAID MOUNTING MEANS, A CONTACT CARRIAGE HAVING CONTACTOR MEANS THEREON AND MOVABLE BETWEEN OPPOSITE POSITIONS IN WHICH THE CONTACTOR MEANS IS RESPECTIVELY IN AND OUT OF ELECTRICAL ENGAGEMENT WITH SAID CONTACTS, A MECHANICAL OVERCENTER MECHANISM INCLUDING A MEMBER MOVABLE BETWEEN OPPOSITE LIMIT POSITIONS, SAID OVER-CENTER MECHANISM ALSO INCLUDING A COMPRESSION SPRING REACTING BETWEEN SAID MOVABLE MEMBER AND CONTACT CARRIAGE, A REVERSIBLE ELECTRIC MOTOR HAVING DRIVING CONNECTION WITH SAID MOVABLE MEMBER AND OPERABLE FOR MOVING THE LATTER TO OVER-CENTER POSITION IN EACH DIRECTION TOWARD ITS OPPOSITE LIMIT POSITION, SAID MOVABLE MEMBER BEING OPERABLE, ACTING THROUGH SAID COMPRESSION SPRING FOR MOVING SAID CANTACT CARRIAGE TO ITS OPPOSITE POSITION IN RESPONSE TO ITS OWN MOVEMENT TO OVER-CENTER POSITION, SAID CONTACT CARRIAGE BEING ROCKABLE ABOUT A CENTRAL LONGITUDINAL AXIS, THE SIDES OF THE CONTACTS INCLUDING CONTACTS ON RADIALLY OPPOSITE SIDES OF THE CONTACT CARRIAGE AND THE CONTACTOR MEANS INCLUDING MOVABLE CONTACTS ON EACH OF RADIALLY OPPOSITE SIDES OF THE CONTACT CARRIAGE CONTACTS, FOR ENGAGING RESPECTIVE ONES OF SAID STATIONARY CONTACTS, WHEREBY THE CONTACT CARRIAGE IS BALANCED BY DISTRIBUTION OF MASS SYMMETRICALLY AROUND SAID AXIS, AND SAID MOTOR BEING MOUNTED WITHIN AND CARRIED BY SAID CONTACT CARRIAGE.

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