US2603732A

US2603732A - Switch

Info

Publication number: US2603732A
Application number: US180190A
Authority: US
Inventors: Maurice B Hinman
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1950-08-18
Filing date: 1950-08-18
Publication date: 1952-07-15
Anticipated expiration: 1969-07-15
Also published as: FR1049459A; GB692238A

Description

July 15, 1952 M. B. HINMAN 2,603,732

SWITCH Filed'Aug. 18, 1950 H is Att-sorey Patented July 15, 1952 SWITCH I Maurice FB. Hinman, Los Gatos, Calif., assigner to General Electric Company, a corporation of New York Application August 18, 1950, Serial No. 180,190

This invention relates to switches and more particularly to starting switches for single phase induction motors.

In the construction of single phase induction motors, an initial rotating field is frequently secured by utilizing two sets of field windings, one being designated a main or running winding and the other being designated a starting winding. These windings' are customarily physically displaced and also electrically displaced, as, for instance, by the use' of a capacitor in series with the starting winding, in order to provide a two phase field for starting the motor. After the motor has come `up to a predetermined speed, the starting winding is customarily removed from the circuit and the'motor operates on the running winding alone. rlvhe removal of the starting winding is frequently secured by the use of a switch actuated by a rspeed-responsive device mounted on the motor shaft.' The improved switch of this invention is particularly adapted for this use, however, it is to be understood that this switch construction may be employed wherever it is desired to open or 'close a circuit in response to movement of a suitable operating mechanism. In the design of switches of this type, lt has been found desirablefto totally enclose the operating parts, except for thefactuating arm, in a dustftightcasing in order to prevent failures due to dirty operating conditions. It is further desirable to design the switch so that it can be disassembled for inspection or replacement of parts without the use of any tools except for the making of external connections. The -switch of this invention is an improvement on the switch shown and described in Patent 2,277,425 to Horace G. Wiest, assigned to the assignee of the present-application.

An object of this "invention is to provide an improved switch structure.

Another object of this invention is to provide an improved switch construction wherein the operating parts are totally enclosed in a dust-tight casing.

A further object of this invention is to provide an improvedy switch construction which can be readily disassembled for' inspection or replacement of parts without the use of tools.

A stil1 further object of this invention is to provide an improved switch construction in which the length of the air gap between contact y s claims. (ci. 20o-1h64) ing description and the accompanying drawing, and the features of novelty which characterize this invention will be pointed out with partic-A ularity in the claims annexed to and forming a part of this specification.

In the drawing, Fig. 1 is a partial sectional side view of a motor provided with the improved switch of this invention; Fig. 2 is a cross-sectional view of the improved switch Aof Fig. 1 showing the contacts in the closed position; Fig. 3 is a cross-sectional view showing the contacts in the open position; Fig. 4 is a broken-Laway end View of the switch of Figs. 1 to 3; and Fig. 5 is a partial sectional View showing a modied form of this switch.

In accordance with this invention; there is provided anA enclosing casing formed of two separable parts. A stationary contact is arranged in the casing and is mounted on a stationary mounting member which is held in position between the casing parts, a portion of the mounting member extending out of the casing for making external connections. An actuating cam is provided in the casing having pivot projections journaled between the casing parts and an operating arm outside the casing operatively 'connected to one of the pivot projections. A movable contact is provided in the casing cooperating with the stationary contact and mounted on a movable mounting 'memben This movable mounting member has a nrst position engaging the cam in its first position, the'contacts being opened at this time. A spring is arranged in compression between a wall of the casing andthe movable mounting member and serves to normally bias the movable mounting member and the cam into the first position so that the contacts are open.

Movement of the operating arm into the second position causes the cam to move the movable mounting member into a second position to close the contacts. When this switch is installed in a motor, the actuating arm is ncrmallyhheld inthe second position by the speed-responsive device on the shaft so that the contacts are closed below a predetermined speed. When the motor obtains the predetermined speed, the speed-responsive device releases pressure yon the actuating arm so that the'spring returns the cam to the first position opening the contacts to break the circuit of the starting winding.

Referring now to Figs. 1 to 4 inclusive, there is shown a motor generally identified as I having a framemember 2 and a cooperating end shield 3 which supports bearing 4 kin which the shaft V5 is journaled. `vThe frame member supports a stator core member 6 which is provided with suitable winding slots (not shown) in which running windings 'I and starting windings 8' are arranged. A rotor member 9 is mounted on the shaft and is provided with a suitable squirrel cage winding (not shown) and short circuiting end rings I0.

The improved switch of this invention, indicated generally by the numeral I I, is mounted'in the end shield 3 in any suitable manner, as by bolt I 2. The contacts of the switch II, as will be hereinafter described in greater detail, are are ranged in the circuit of the starting windings 8 and are adapted to open the circuit of the starting windings at a predetermined speed responsive to the action of the speed-responsive centrifugal mechanism I3 mounted on the shaft 5. The centrifugal mechanism I3, which may be of any suitable type, is shown here as including a push collar I4 mounted for axial movement on the shaft 5 responsive to movement of the outwardly movable weightportions I5. The-centrifugal mechanism I3 is shown in Fig. 1 in the standstill or low speed condition; however, when the predetermined speed is attained above which the starting windings 8 are not required, the weight portions I5 move outwardly against the bias of the Y spring I6 causing the push collar I4 to move toward the right in the direction of the rotor 9. This movement of the push collar I 4 permits the operating arm II of the switch to move from the position shown in Fig. 1 into another position to open the switch contacts.

Referring now particularly to Figs. 2, 3 and 4, the switch II is provided with an enclosing casing member I8 formed of two separable parts I9 and 20. The two casing `parts I9 and 20 may be moulded of any suitable insulating material in any of the various methods well known in the art. The peripheral edges of the sides 2I and 22 of casing part 20 are provided with slots 23 in which a stationary mounting member 24 is positioned. Thus, when the two casing parts I9 and are assembled, the mounting member 24 is held in position therebetween and is insulated thereby from the ground and from the other conducting parts. The mounting member 24 is made of a conducting material and is provided with an extension 25 extending outside the casing for making external connections to the switch.

A stationary contact 26 is secured to the mounting member 24 in any suitable manner. Openings 2'I are formed through the casing parts I9 and 29 to accommodate the mounting bolts I2. A movable contact 28 is provided mounted on a movable contact member 29 in any suitable manner. Actuating cam member 30 is arranged within the casing I8 and is provided with a relatively flat surface 3I and a relatively long portion 32 extending on the side of the fulcrum of the cam remote from the stationary contact 26. The cam 30 is provided with a pair of pivot projections 33 which are journaled in openings 34 formed in the peripheral edges of the sides of the casing parts I9 and 20. are held in position when the casing parts I9 and 26 are assembled together. One of the pivot projections 33 is provided with an extension portion 35 extending out of the casing I 8 to which operating arm I 'I is secured. The casing part I9 is provided with a spring seat 36 formed on its inner surfaceand a corresponding spring seat 3'! is formed onthe extension 32 of the actuating cam member 3,0 extending through an opening 38 formed kinthe movable mounting member 29.

Thus, the pivot projections 33 A spring 39 is arranged in compression between the spring seat 36 and the spring seat 31, engaging the inner surface of the casing part I9 and the portion 40 of the movable mounting member 29 remote from the movable contact 28. A terminal 4I is mounted between the casing parts I9 and 29 and is provided with an extension 42 extending outside the casing I8 for making external connections to the movable contact 29. The terminal 4I is also provided with an internal connecting portion 43 and a flexible pigtail 44 connects the portion 43 of the terminal 4I and the movable contact mounting member 29. A spring wire clamping member 45 serves to hold the two casing parts I9 and 20 and the enclosed operating parts in assembled position.

For purposes of clarity, the operation of the switch will first be discussed in reverse order, referring first to Fig. 3, with the push collar I4 moved axially to the right out of engagement with the operating arm I'I, the spring 39 normally biases the movable mounting member 29 and the actuating cam member 30 into the position shown in which the extension portion 40 of the movable mounting member 29 lays on the substantially flat portion 3| of the actuating cam member 32 so that the movable contact 28 is spaced from the 'stationary contact 26 to provide the open contact position. When the push collar I4 moves tothe left, as shown in Fig. 2, to engage the operating'arm I'I and move 'it in turn to the left, the initial movement of the operating armvI'I away from the position shown in Fig. 3 causes the cam member 30 to pivot with the extension 32 moving toward the left. Since the movable mounting member 29 is biased against the cam member 39 by the spring 39, the movable mounting member 29 initially remains fiat against the surface 3l of the cam 30 until the

contacts

28 and 26 are closed. Further movement of the operating arm/I1 tothe left causes the end of the extension 49 of the'movable mounting member 29 to pivot about its point of engagement with the extension 32 of the vcam 30 so that wiping pressure is applied 'by the movable contact 28 to the stationary contact 26, as shown in Fig. 2. It will be understood, of course, that the sequence of operation when the motor is starting from rest is the reverse from that described above, i. e., the contacts `2li and 28 being initially closed and the operating arm moving to the right as shown in Fig. 3 under the influence of the spring 39 to open the contacts. Stop portion 46 is integrally formed on the interior surface of the casing part I9 to limit the travel of the movable mounting member 29, as shown in Fig. 3, thus controlling the gap between the open contacts.

Referring now 'to Fig. 5, in which like parts are indicated by like reference numerals, a stationary back contact 4'I is provided in the place occupied by the stop 46 in Figs. 2 and 3; This contact is connected to an exterior terminal 48 positioned in groove 49 in the exterior surface of the casing part I 9. The construction of Fig. 5 therefore provides a double throw switch, rather than the single throw arrangement of Figs. 2` and 3.

It will now be readily apparent that this invention provides an improved switch construction in which all of the operating parts, with the exception of the operating arm, are enclosed in a dust-tight casing to prevent failures due to dirty operating conditions. It will be further readily apparent that all of the operating parts are held in their assembled position by the assembly of the casing parts I9 and 20 and that What I claim as new and desire to secure by Letters Patent of the lUnited States is:

1. A switch comprising an enclosing casing having two separable parts, a stationary contact in said casing Amounted on a stationary mounting member rheld in position by the joint `between said casing parts when assembled, said stationary mounting member having a portion extending out of said casing for making external connections to said stationary contact, an actuating cam in said casing having pivot projections journaled betweeny said casingr partsnat said joint at each side of the casing, an operating arm outside said casing and operatively connected to one of said pivot projections, said arm being adapted to be moved from a first position into a second position whereby said cam is correspondingly moved, a movable contact in said casing cooperating with said stationary contact, said movable contact being mounted on a movable contact mounting member, said movable mounting member having a :first position engaging said cam member in its rst position, said movable contact being spaced from said stationary contant in said rst position of said cam member and said movable mounting member, and a spring in said casing arranged in compression between said movable mounting member and a wall of said casing for normally biasing said movable mounting member and said cam into said rst position, movement of said operating arm into its second position causing said cam to move said movable mounting member into a second position to close said contacts.

2. A switch comprising an enclosing casing having two separable parts, a stationary contact in said casing mounted on a stationary mounting member held in position by the joint between said casing parts when assembled, said stationary mounting member having a portion extending out of said casing for making external connections to said stationary contact, an actuating cam in said casing having pivot projections journaled between said easing parts at said joint at each side of the casing. an operating arm outside said casing and operatively connected to one of said pivot projections, said arm being adapted to be moved from a rst position into a second position whereby said cam is correspondingly moved, a movable contact in said casing cooperating with said stationary contact, said movable contact being mounted on a movable contact mounting member, said movable mounting member having a rst position engaging said cam member in its rst position, said movable contact being spaced from said stationary contact in said rst position of said cam member and said movable mounting member, a spring in said casing arranged in compression between said movable mountlng member and a wall of said casing for normally biasing said movable mounting member and said cam into said first position, movement of said operating arm into its second position causing said cam to move said movable mounting member into a second position to close said contacts, and removable clamping meansv for holding said casing parts together whereby said mounting members,

'said cam and said spring are held in assembled relation. Y

3. A switch comprising an enclosing casing having two ,separable parts, a stationary contact in said casing mounted on a stationary mounting member held in position between said casing parts at the junctionv thereof, said stationary mounting memberhavinga portion extending out of said casing for making external connections to said stationary contact, an actuating cam in said casing having pivot projections journaled betweenA said casing parts at the junction thereof, an operating arm outside said casing and operatively connected to one of said pivot projections, said arm being adapted to be moved from a rst position into a second position wherebysaid cam is correspondingly moved, a movable contact in said casing cooperating with said' stationary contact, said movable contact being mounted on a movable contact mounting member, said movable mounting member having afirst position engaging said cam member ink its first position, said movable contactbeing spaced from said stationary contact in said rst position of said cam member and said movable mounting member, a spring in said casing arranged in compression between said movable mounting member and a wall of said casing for normally biasing said movable mounting member and said cam into said first position, movement of said operating arm into its second position causing said cam to move said movable mounting member into a second position to close said contacts, a terminal mounted between said casing parts having a portion extending out of said casing for making external connections to said movable contact, said terminal having another portion in said casing, and a flexible electrical connection between said other terminal portion and said movable contact.

4. A -switch comprising an enclosing casing having two separable parts, a stationary Contact in said casing mounted on a stationary mounting member held in position between said casing parts, said stationary mounting member having a portion extending out of said casing for making external connections to said stationary contact, an actuating cam in said casing having pivot projections journaled between said casing parts, an operating arm outside said casing and operatively connected to one of said pivot projections, said arm being adapted to `be moved from a rst position into a second position whereby said cam is correspondingly moved, a movable contact in said casing cooperating with said stationary contact, said movable contact being mounted on a movable mounting member, said movable mounting member having a rst position engaging said cam member in its first position, said movable contact being spaced from said stationary contact in said first position of said cam member and said movable mounting member, a spring seat formed in an interior wall of one of said casing parts, said movable mounting member having an opening formed therein, a spring seat portion formed on said cam member and projecting through said movable mounting member opening, and a spring in said casing arranged in compression between said spring seats for normally biasing said movable mounting member and said cam into said rst position, movement of said operating arm into rits second position causing said cam to move said movable mounting member into a second position to close said contacts.

5. A switch comprising an enclosing casing having two separable parts, a stationary contact in said casing mounted on a stationary mounting member held in position between said casing parts, said stationary mounting member having a portion extending out of said casing for making external connections to said stationary. contact, an actuating cam in said casing having pivot projections journaled between said casing parts, said cam having a relatively flat surface and a portion extending on the side of said pivot projections remote from said stationary contact, an operating arm outside said casing and operatively connected to one of said vpivot projections, said arm being adapted to beV moved from a first position to a second position whereby said cam is correspondingly moved, a movable contact in said casing cooperating with said stationary contact, said movable contact being mounted on a movable mounting member, said movable mounting member having a iirst position laying on said iat surface of said cam in its first position, said movable contact being spaced from said stationary contact in said first position of said cam and said movable mounting member, and a spring in said 8 casing arranged in compression between said movable mounting member and a wall `of said casing for normally biasing said movable mounting member and said cam into said iirst position, initial movement of said operating arm away from said rst position causing said movable mounting member to move with said cam until said movable contact engages said stationary contact, further movement of said operatingA arm into its second position causing the end of said movable mounting member to pivot on the end of said cam remote from said stationary contact into a second position whereby said movable contact applies wiping pressure on said stationary contact.

MAURICE B. HINMAN.

REFERENCES CITED4 The following references are of record in the le of this patent:

UNITED STATES PATENTS