US3227828A

US3227828A - Pivotally operable circuit interrupter

Info

Publication number: US3227828A
Application number: US145190A
Authority: US
Inventors: Gerald W Jones
Original assignee: Maytag Corp
Current assignee: Maytag Corp
Priority date: 1961-10-16
Filing date: 1961-10-16
Publication date: 1966-01-04
Anticipated expiration: 1983-01-04

Description

jam. 4, W65 (3. w. JONES 3,227,828

PIVOTALLY OPERABLE CIRCUIT INTERRUPTER Filed Oct. 16. 1961 United States Patent 3,227,828 PIVOTALLY OPERABLE CIRCUIT INTERRUPTER Gerald W. Jones, Newton, Iowa, assignor to The Maytag Company, Newton, Iowa, a corporation of Delaware Filed Oct. 16, 1961, Ser. No. 145,190 Claims. (Cl. 2200-46) This invention relates as indicated to switch mechanisms, and more particularly to switch mechanisms operated by cams, for example, in connection with timer controls. a

In some conventional timing mechanisms, disc cams are secured to a shaft driven by a timing motor. The disc c ams operate electrical switch for controlling the time in sequence of a program of operations.

Co-pending application of Thomas R. Smith, Serial No. 144,874, filed October 13, 1961, now Patent No. 3,178,- 525, assigned to the same assignee, relates to timing mechanisms operated by an endless belt.

Whether a disc cam, or an endless belt, is employed to operate the switch mechanisms, problems of the switch contacts sticking are encountered. For example, as the switch is opened and closed, particularly at slow rates, an electrical arc may be produced between the separated contacts, which will generate enough heat to weld them together. When the contacts are welded together, the switch is inoperative, and must be repaired or replaced.

It is, therefore, an object of the invention to provide switch mechanisms suitable for operation in timer controls. It is a further object of the invention to provide switch mechanisms, which will reduce, or substantially eliminate, the problems of sticking between switch contacts, It is a still further object of the invention to provide switch mechanisms, which are self-repairing; that is, in-the event sticking does occur due to welding caused by electrical arcing, the switch will operate to correct this condition. It is another object of the invention to provide switch mechanisms operable by an endless belt.

It is still another object of the invention to provide a timing mechanism which may be easily inspected and repaired. Further objects of the invention will become evident as the description proceeds and from an examination of the accompanying drawings which illustrate several embodiments of the invention and in which similar numerals refer to similar parts throughout the several views.

In the drawings:

FIGURE 1 is a side view in elevation of switch mechanism embodying the invention;

FIGURE 2 is a bottom view of the switch mechanism of FIGURE 1;

FIGURE 3 is an enlarged view of switches employed in the switch mechanism of the invention.

Referring now to FIGURES 1 and 2 of the drawings, a timing mechanism is illustrated having a frame 11. An endless belt 12 is movably supported between

rollers

14, 15, 16 and drum 17 journalled on the frame. The drum 17 is driven by motor 20 through transmission 21. Motor 20 drives the transmission 21 through motor shaft 22. Transmission 21 drives drum 17 through shaft 18.

Transmission 21 drives the drim shaft 17 at a slow timing'speed, and at high rapid advance speeds. The slow timing speed is used to advance the endless belt 12 in timed sequential positions of operations, The high speed is used to rapid advance the endless belt during switching operations, or to select a desired position in the cycle, as more fully described hereinafter.

Transversely across the endless belt 12 is mounted cross piece 24 on frame 11. Supported on the cross piece, adjacent the endless belt, are a number of switches, for example, switches 31 351.

Referring now to FIGURE 3, there is shown an en- 3,227,828 Patented Jan. 4, 1966 larged view of switches 30, 30', in cross section and elevation, respectively. Switches 311 and 30 are mounted on cross piece 24. The following description is concerned with switch 30, although the other switches are similarly constructed.

Switch 311 has

terminals

31, 32 to switch may be attached the leads to the device to 'be controlled.

Terminals

31, 32 are adapted to receive removable fittings for the leads (not shown), so that they may be readily taken off, if it is necessary to replace the entire bank of switches on cross piece 24. The switches mounted on the cross piece 24 may be quickly inspected and repaired by removal of cross piece 24 from the frame 11, without detaching the leads from the terminals.

The

terminals

31, 32 are connected electrically to

contacts

33, 34 respectively.

Bridging contacts

33, 34 is a switch blade member 36 having

contacts

37, 38 normally engaging

contacts

33, 34 so that there is electrical continuity between

terminals

31, and 32. The switch blade 36 is biased by spring 39 mounted within a housing 40 so that

contacts

37, 38 are held against

contacts

33, 34. Depending from the switch blade 36 is a cam follower 44, having an inclined bottom edge 45. The cam follower 44 is adapted to project through opening 46 in the endless belt 12. When the belt is moved from right to left, as shown in FIGURE 3, edge 45 of the cam follower 44 will be contacted by belt 12 at the end of opening 46 which :acts as a cam. As the belt continues its movement and cam action, the cam follower 44 will raise the switch blade 36, as illustrated by the position of the switch blade 36 of switch 30'. When the switch blade 36 is lifted by the coaction of the belt 12 against the cam follower 44, contact 37, or 38, or both, are lifted from engagement with the

contacts

33, 34 to break the electrical connection between

terminals

31, 32. As shown by the switch 3%, the switch blade 36' has rocked, or rotated, about contact 38' so as to lift and separate the contact 37 from contact 33' to break the electrical connection between the terminals 31' and 32.

As best shown in FIGURE 1, openings, or slots, 46 are formed in the endless belt 12 at preselected locations to cause the desired sequential cycle of operation by actuation of the various switches, such as 30 and 30 at the proper time. The switches may be mounted at spaced transverse positions, to be operated by openings 46 formed in belt 12 along a longitudinal path.

It will be apparent that various modifications to the belt may be made. For example, rather than slots in belt 12, ridges, or rises, on the belt may be used to operate the cam flolowers 44, in order to achieve the same results.

The transmission 21 for driving the belt at low and high speeds is described in the co-pending application of Thomas R. Smith, Serial No. 144,874, filed October 13, 1961, now Patent No. 3,178,525 and assigned to the same assignee.

As best shown in FIGURE 2 on the outer surface of the housing 64 is mounted a spring biased arm pivoted at 76 on a pin secured to the housing 64. The arm 75 at its outer end has a finger '78 which is normally withdrawn from the periphery of housing 64 by spring 79. In this condition transmission 21 rotates shaft 18 at a slow rate of speed. However, when the arm 75 is pivoted about '76 against spring 79, finger 78 projects or extends away from the periphery of housing 64 so that it engages stop or abutment 81 on frame 11. In this condition transmission 21 rotates shaft 18 at a high rate of speed.

Thus, it will be seen that endless belt 12 may be advanced by the transmission 21 at slow and high speeds. The slow speed is used to time the sequential operations of the switches 30. The high speed is used to advance the belt for operation of the switches 30. Thus, when switch 30 is to be opened the belt 12 is rapidly advanced for an interval concurring with the operation speed of the switch so that the switching takes place rapidly. The timing belt is normally advanced at slow timing speeds but is rapidly advanced in connection with and during the period of the switching operations of switches 30. In addition, the rapid advance mechanism may be used to locate the timing at a desired point in the cycle.

As best shown in FIGURES l and 2 transmission 21 is actuated to high speed by trigger lever 83 pivotally sup ported on bracket 34 on frame 11. The trigger lever 83 has on one end a finger 86 which engages the bottom surface of belt 12. The finger 86 is biased into engagement with the belt 12 by spring 87. The opposite end of trigger lever 33 is provided with the second finger 89 normally spaced away from the arm 75 on housing 64.

Openings or slots 91 are formed in the belt 12 at locations which correspond to periods of time at which the belt 12 is to be rapidly advanced at high speeds. When the finger 86 enters an opening 91, the trigger lever 83 is pivoted so that finger 89 moves toward the housing 64 and engages arm 75. When finger 39 engages and pivots arm 75 during the rotation of housing 64, finger 78 is extended so it engages the stop 81. When the finger 78 engages stop 81, shaft 18 and endless belt 12 are rapidly advanced at high speeds. After the period of time determined by the length of slot 91, the lever 83 is returned to the normal position against spring 87 and transmission 21 again rotates the belt at a slow timing speed. 1

It may he sometimes desirable to position the belt 12 at a desired operation in the cycle. This may be accomplished by manually depressing the plunger 100. Plunger 100 is movably mounted on

brackets

101, 102 secured to frame 11. The end 104 of plunger 100 is adjacent the face of housing 64 and is normally biased away therefrom by spring 105. When the plunger 100 is manually depressed, end 104 assumes a position in the path of and the end of lever 75 so as to hold the housing 64 against rotation. As explained hereinabove, holding the housing 64 against rotation causes rapid advance of shaft 18. When the plunger 100 is released the lever 75 is disengaged, with the result that shaft 18 again rotates at a slow timing speed.

The return spring 105 is mounted between bracket 102 and abutment 106 on plunger 100. The abutment 106 has an outer surface which acts as a cam to disconnect the power to the switches, for example, 30, 30, during the time the belt is advanced at high speeds.

Switch 110 is in electrical series with the power for both the rotor and switches, for example 30, When the plunger 100 is in normal position the button 115 of switch 110 is engaged by abutment 106 on plunger 100 to supply power to the motor and switches. However, when plunger 100 is depressed the abutment 106 is disengaged from switch button 115 so that the power to the motor and switches is disconnected.

Switch 112 is in series with an alternate power supply to motor 20. The alternate power supply through switch 112 is parallel to the power supply to motor 20 through switch 110. When the plunger 100 is depressed the abutment 106 engages switch button 116 of switch 112 so that motor is energized, but the switches remain deenergized. The result obtained by manually depressing plunger 100 then is to cause rapid advance of the belt 12, and at the same time disconnect the power supply to the switches.

From the foregoing it is believed that operation of the timing mechanism of the invention is apparent. Switches, such as 30, 30, adapted to control the various operations of a programmed cycle, are transversely spaced across the face of the belt 12. The belt is provided with suitable cam formations for operating the preselected switches at predetermined times so as to obtain the desired sequence and time of operation. During the period concurring with the operation of the switches, transmission 21 advances the belt at high speeds, after which the belt is returned to normal slow timing speed. The rapid advance is preset to occur at the proper intervals by openings or slots 91 in the belt which operate a lever 33 to control the transmission 21.

The belt 12 may be rapid advanced by manual depression of the plunger 100. As long as the plunger is depressed the belt 12 will be advanced at high speeds. Thus, a separate manually operable device may be used to selectively advance the belt to desired positions.

The belt 12 may be of various lengths to control a number of switching devices, or to control a large number of operations. The belt may be folded back and forth with the frame 11, as between

rollers

14, 15 and 16, to keep the mechanism compact.

The switch mechanisms heretofore described have many unique advantages. Referring to FIGURE 3, the switch blade 36 when opened by belt 12 rotates, or rocks, about contact 38, as shown by switch 30, so that, if any welding caused by arching between

contacts

34, 38 has occurred, then the pivoting or rocking action will rupture the connection. In this way any sticking between 34, 38 will be corrected.

In the

event switch contacts

33, 37 are welded shut, the follower 44 will separate the

switch contacts

34, 38, so as to break the electrical connection. At the same time, the rocking or pivoting action of contact 37 on contact 33 will sever the mechanical connection between 33 and 37, which caused the sticking. In this way, the switch operates to prevent, and repair, sticking, such as may be produced by welding of the contacts through electrical arching.

Another advantage of the invention is the facility by which the switches, for example, 30, 30, may be inspected and repaired. The entire cross piece 24 may be readily removed from the frame 11 without disconnecting the leads (not shown) on the terminals.

In the drawings and specification there have been set forth several embodiments of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only, and not for purposes of limitation. Changes in form and proportion of parts, as well as the substitution of equivalents are contemplated, as circumstances may suggest or render expedient, without departing from the spirit or scope of this invention as further defined in the following claims.

I claim:

1. In a switch mechanism, first and second electrical terminals, first and second electrical contact members, said first and second contact members electrically connected to first and second electrical terminals, a movable switch member engaging both of said first and second contact members for making the electrical circuit between said first and second contact members, means for pivotally actuating said switch member for disengaging at least one of said contact members by pivoting said switch member about one terminal to break said electrical circuit, and means biasing said movable member against said first and second contact members and at the same time opposing said means for pivotally actuating said switch member.

2. In a switch mechanism, first and second contact members, a movable switch blade, said switch blade at one end removably engaging said first contact member and at the other end removably engaging said second contact member for establishing electrical continuity between said first and second contact members, means for disengaging said switch blade from at least one of said contact members by pivotal movement of said blade about one of said contact members in order to break electrical continuity between said first and second contact members, and spring means biasing said switch blade against said first and second contact members and at the same time opposing said disengaging means.

3. In a switch mechanism, first and second contact members, a movable switch member, said switch member at one end portion removably engaging said first contact member and at the other end portion removably engaging said second contact member for establishing electrical continuity between said first and second contact members, follower means for pivotally disengaging said switch member from at least one of said contact members in order to break electrical continuity between said first and second contact members, spring means biasing said switch member against said first and second contact members, and cam means in the form of a movable belt for pivotally actuating said follower means.

4. In a switch mechanism, first and second contact members, a movable switch blade having first and second end portions, said switch blade at said first end portion removably engaging said first contact member and said second end portion removably engaging said second contact member for establishing electrical continuity between said first and second contact members, follower means for pivotally disengaging said switch blade from at least one of said contact members in order to break electrical continuity between said first and second contact members, spring means biasing said switch blade against said first and second contact members, and cam means for pivotally actuating said follower means.

5. In a switch mechanism, a support, first and second electrical contact members mounted at spaced points on said support, a switch member pivotably mounted with respect to said support and removably engaging both of said contact members, said switch member having first and second portions and a cam follower portion, spring means biasing said first and second portions of the switch member into electrical engagement with said first and second contact members for establishing electrical continuity between said first and second contact members in order to make a circuit, cam means, means for advancing said cam means, said cam means controlling actuation of said cam follower portion with a component of force overcoming said spring means to normally pivot said switch member about said first contact member and upon sticking of said second contact member to pivot about said second contact member to break the circuit between said first and second contact members.

References Cited by the Examiner UNITED STATES PATENTS 1,641,658 9/1927 Berglllnd ZOO-61.18 2,025,697 12/1935 Baker 200-146 2,523,184 9/1950 Beall 200-61.14 2,671,836 3/1954 Anger et al 20016 2,773,950 12/1956 Bauer 20016 2,884,495 4/1959 Frankel 2006l.13 2,892,047 6/1959 Smith 200 2,911,634 11/1959 Ferguson 200-61.13

BERNARD A. GILHEANY, Primary Examiner.

Claims

1. IN A SWITCH MECHANISM, FIRST AND SECOND ELECTRICAL TERMINALS, FIRST AND SECOND ELECTRICAL CONTACT MEMBERS, SAID FIRST AND SECOND CONTACT MEMBERS ELECTRICALLY CONNECTED TO FIRST AND SECOND ELECTRICAL TERMINALS, A MOVABLE SWITCH MEMBER ENGAGING BOTH OF SAID FIRST AND SECOND CONTACT MEMBERS FOR MAKING THE ELECTRICAL CIRCUIT BETWEEN SAID FIRST AND SECOND CONTACT MEMBERS, MEANS FOR PIVOTALLY ACTUATING SAID SWITCH MEMBER FOR DISENGAGING AT LEAST ONE OF SAID CONTACT MEMBERS BY PIVOTING SAID SWITCH MEMBER ABOUT ONE TERMINAL TO BREAK SAID ELECTRICAL CIRCUIT, AND MEANS BIASING SAID MOVABLE MEMBER AGAINST