US2507381A - Switch mechanism - Google Patents

Description

y 9, 1950 G. MORSE 2,507,381

SWITCH MECHANISM Filed Aug. 17, 1945 2 Sheets-Sheet 1 cw INVENTOR.

May 9, 1950 G. MORSE SWITCH MECHANISM Filed Aug. 17, 1945 Zing .&

2 Sheets-Sheet 2 INVENTOR. 6/2/7 )74/"56.

Patented May 9, 1950 2,507,381 SWITCH MECHANISM Glenn Morse, Ann Arbor, Mich., asslgnor to King- Seeley Corporation, Ann Arbor, Mich., a corporation of Michigan Application August 17, 1945, Serial No. 611,114

The present invention relates to switch mechanlsms, and is particularly directed to the provision of improved light duty switches. An illustrative application of the invention is in connection with switches which are utilized in connection with time controlled apparatus, such as range timers, washing machine timers, and the like.

Principal objects of the present invention are to provide switch structures which are simple in arrangement, economical of manufacture and assembly, and which are reliable and efiicient in operation; to provide such structures employing electrically interconnected main and secondary movable contacts, which cooperate with corresnondingly electrically interconnected main and seondary fixed contacts; to provide such structures wherein the movable contacts are carried by a flexible element which is so constructed that the moving contacts engage, and/or disengage irom the cooperating fixed contacts in succession; to provide such structures wherein each switch closing operation involves a wiping action of at least certain of the engaged pairs of fixed and movable contacts; and to generally improve and simplify the construction and arrangement of switch structures or the above generally indicated type, particularly those suited for light duty operation.

With the above as well as other andmore detailed objects in view, which appear in the following description and in the appended claims, pref erred but illustrative embodiments of the invention are shown in the accompanying drawings,

throughout the several views of which correspondmg reference characters are used to designate corresponding parts, and in which:

Figure 1 is a view in side elevation. of a structure embodying the invention;

Figure 2 is a view in rear elevation, taken along the line 2-2 of Figure 1;

Figure 3 is a view in section, taken along the line 33 of Figure 1;

Figure 4 is a side view of the switch, taken along the line 4---& of Figure 2; and,

Figure 5 is an interior view of the switch structure, taken along the line 5 -5 of Figure 3.

It will be appreciated from a complete understanding of the present invention, that, in a generic sense, the improvements thereof may be embodied in switch structures of varying diflferent types, arranged for various types of service, and constructed to handle currents of varying different magnitudes. An illustrative but not limiting application of the invention is in con- 5,5

4 Claims. v(Cl. 200-166) nection with relatively light duty switches, such, for example, as range or washing machine timers.

Referring first to Figures 1 through 5, the illustrative timer I0 is received within a housing or case l2 and may, of course, include any suitable mechanism (not shown) which serve to drive the main arbor It at a controlled rate and has as a part thereof, a rotatable shaft l6 which is utilized to control the opening and closing of the illustrated switch it. Post 20 is arranged to be pushed inwardly in response to a counterclockwise rocking movement of a lever 21, which is carried by the shaft it for closure of the switch l8 through a flexible element 24, interposed between post 20 and lever 21.

Referring particularly to Figures 3, 4, and 5, switch I8 is provided with a flexible contact element 26, which may be formed of any good conducting material having springlike characteristics. Contact element 25 carries a pair of spaced moving contacts 28 and 30, which are electrically interconnected through the body of the element 26, and which are disposed to cooperate, respectively, with fixed contacts 32 and 3. Contacts 32 and 34 are carried and electrically interconnected, by a conducting bracket 36. A rivet 38, of which contact 32 may form a part, serves to rigidly connect bracket 36 to a substantially flat closure plate 40. Rivet 38 also connects one of the two exposed terminals 42 and 44 to the closure plate 40, and electrically interconnects such one terminal to the bracket 36.

Contact element 26 is provided with a reversely turned end portion 46, which is anchored to the closure plate 40, by means of a headed rivet 48, which also supports the other exposed terminal 44. As appears in Figure 5, the side of the reversely-turned end portion 46 is notched as indicated at 50, so that it may be slipped under the head of the rivet 48, in assembling the structure.

The end of the reversely turned portion 46 is also notched as indicated at 52, to accommodate the insulating post 54, which may be and preferably is formed integrally with the outer closure member 56. Member 55 defines a pair of recesses 58 and 60, which accommodate the previously mentioned exposed terminals 42 and 44.

It will be noticed that the housing I8 is completed by the cup-shaped housing member 62, closure plate being interposed between the members 56 and 62. The housing members are maintained in assembled relation to each other, by an outer enclosure 64, having an inwardly turned marginal flange 66. The cup-shaped hous- 1 this elementis provided with a laterally oiiset intermediate portion l2,whichconstitutesapressure applying portion to receive the enlarged head ll ofthe previously mentioned operating post 26. Element 26 normally tends to move in a direction to separate the respective pairs of moving and nxed contacts, ahmit to such separating movement being ailorded by the post 26, the head. I4

whereof seats against the inner face of the cupshaped housing 62. A limit to inward movement of the contact element 28, under the influence oi the post 20, is afforded by the engagement between the portion 12 of contact element 26 with the inner end 64a of the previously mentioned central post 54.

Before describing the operation of the structure, it will be noticed that thecontacts 26 and II are carried, respectively, by portions 260 and 26b, which extend approximately at right angles to each other.

Considering now the operation of the structure of Figures 1 through 5, the parts normally occupy the open position shown in Figure 3. The contact element 26 tends to widen the angle defined by the reversely turned portion 16, and so yieldingly biases the portion 12 into engagement with the head ll of the post and retains the latter in its illustrated limit position. To close the switch, post 26 may be moved inwardly and, as stated above, this may be caused by-a rocking movement of the lever 22. The portion 16 embodies considerably less resistance to flexure than do the portions of the strip in the region of the laterally offset portion 12. Consequently, in response to the initial inward movement of the post 20, substantially all of the flexure of the element 26 takes place at or near the reverse bend I6. Such movement of the contact element 26 carries con= tact 28 into engagement with fixed contact 32. and consequently electrically connects the external terminals 42 and 44. Continued inward movement of the post 26 serves to flatten out the element 26; that is to say, it serves to cause flexure of the strip, at or in the regions of the angles 26a, 26b, 26c, 26d, 26c, and 26!. Such flattening out increases the effective length of the element 26, and ultimately causes contact 30 to engage contact 34. In addition to causing the just-mentioned engagement, such lengthening also causes contact 28 to slide alon the contact 32, with a wiping action. The engagement between contacts 30 and 34 may be expected to occur somewhat before the end 58a of post 64 is engaged by the portion '2. Continued inward movement of post 20, after engagement of contacts 30 and 34', causes continued flattening out of the strip, and also causes some bending of the contact element 26 at the junctionbetween the angularly related portions 26a and 26b. Such latter bending, as will be understood, introduces a slight amount of wiping action between contacts 30 and 34.

It will be appreciated that the contact element 26, may be constructed so as to provide any of a variet of different ratios between the resistances to flexure at the region of the bend l6, and in the region of the offset portion I2. Preferably, the resistance to bending in the region of the portion I2 is from two to three times that in the region of the bend 16. With this relation, engagement of contacts 28-32, prior to engagement 0! con tacts 30-24, is insured.

To open the switch, the operating pressure on post 26 may be relieved and, ordinarily, such pressure is relieved rather abruptly. Even the reduction in operating pressure on post 26 requires some little time, of, perhaps, the order of .01 second. As soon as such pressure falls below the value necessary to flatten out the offset portion 12, the contact element 26 begins to recover its original =laterally oifset shape, which recovery shortens the strip and separates contacts at and 24. At the time of such separation, the pressure applied to the post 26 may be expected to be well above the pressure needed to hold contacts 28 and 32 in engagement with each other. However, as the post pressure continues to fall after contacts 30-34 are separated, such pressure ultimately enables the strip 2% to separate contacts 26-32, and resume the normal position shown in the drawings.

Summarizing the above operation, it will be recognized that contact element 26 is arranged to flex in two diflerent regions, capable of imposing difierent resistances to fiexure. Flexure about the weaker of these portions controls the engagement and disengagement of one pair of contacts and flexure about the other of these por tions controls the engagement and disengagement of another pair of contacts. Consequently, in each closing movement, contacts 28 and 32 en= gage each other prior to the engagement of contacts tt-td, and in each opening movement, contacts tit-3d separate prior to separation of contacts 28-32. Each closing and each opening movement also introduces a wiping action between the cooperating fixed and movable contacts. As will be understood, the successive opening and closing action substantially frees contacts 30-34 from any arcing action, all such arcing being confined to contacts 28-32 which can, therefore, be regarded as the secondary or arcing contacts of the present switch construction.

Although only one specific embodiment of the invention has been described in detail, it will be appreciated that various modifications in the form, number, and arrangement of the parts may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a switch structure, a supporting member, a pair of spaced electrically interconnected relatively fixed contacts, a flexibl element having one end portion secured to said member and formed to provide a first flexure point, a pair of spaced electrically interconnected movable contacts mounted on said element adjacent its other end, said element being deformed intermediate said first fiexure point and said movable contacts to provide an oilset portion and a plurality of flexure points, said flexible element being so con= structed that upon application of a flexing force to said element the principal fiexure occurs at said flexing points, said element first flexing primarily at said first fiexure point to permit engagement of one of said movable contacts with its cooperating relatively fixed contact and subsequently flexing primarily at said plurality of tiexure points to efiect a partial straightening of said ofiset portion causing an increase in the efiective length of said element and movement of the other of said movable contacts into engagement with its cooperating relatively fixed contact, and means for applying a said flexing force to said element.

2, In a switch structure, a supporting member,

a pair of spaced electrically interconnected relatively fixed contacts, a flexible element having one end portion secured to said member and formed to provide a first flexure point, a pair of spaced electrically interconnected movable contacts mounted on said element adjacent its other end, said element being deformed intermediate said first fiexure point and said movable contacts to provide an oifset portion and a, plurality of flexure points, said flexible element being so constructed that upon application of a flexing force to said element the principal flexure occurs at said flexing points, said element first flexing primarily at said first flexure point to permit engagement of one of said movable contacts with its cooperating relatively fixed contact and subsequently flexing primarily at said plurality of flexure points to effect a partial straightening of said oflfset portion causing an increase in the efiective length of said element and movement of the other of said movable contacts into engage ment with its cooperating relatively fixed contact, and means for applying a said flexing force to said ofiset portion of said element.

3. In a switch structure, a supporting member, a pair of spaced electrically interconnected relatively fixed contacts disposed substantially at right angles to each other, a flexible element having one end reversely turned and secured to said member and a portion adjacent its other end turned through an angle of substantially 90, a first movable contact mounted on said element adjacent said portion of said element and adapted to engage one of said fixed contacts, a second movable contact electrically connected to said first movable contact, disposed on said portion of said element and adapted to engage the other of said fixed contacts, said element intermediate said one end and said first movable contact having an offset portion adapted for application of a flexing force thereto, said element being so constructed and arranged that upon application of said flexing force said element first flexes primarily at the reverse turn adjacent said one end to permit said first movable contact to engage its cooperating relatively fixed contact and subsequently flexes to spread said ofi'set portion toward a straightened position causing an increase in the eflective length of said element and moving said second movable contact into engagement with its cooperating relatively fixed contact, and means for applying a said flexing force to said offset porti 4. In a switch structure, a supporting member,

a pair of spaced electrically interconnected relatively fixed contacts disposed substantially at right angles to each other, a flexible element having one end reversely turned and secured to said member and a portion adjacent its other end turned through an angle of substantially 90", a first movable contact mounted on said element adjacent said portion of said element and adapted to engage one of said fixed contacts, a. second movable contact electrically connected to said first movable contact, disposed on said portion of said element and adapted to engage the other of said fixed contacts, said element intermediate said one end and said first movable contact having an offset portion adapted for application of a flexing force thereto, said element being so constructed and arranged that upon application of said flexing force said element first flexes primarily at the reverse turn adjacent said one end to permit said first movable contact to engage its cooperating relatively fixed contact and subsequently flexes to spread said ofi'set portion toward a, straightened position causing an increase in the eifective length of said element and sliding said first movable contact on its cooperating relatively fixed contact and moving said second movable contact into engagement with its cooperating relatively fixed contact, and means for applying a said flexing force to said offset portion.

GLENN MORSE.

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

UNITED STATES PATENTS May 18, 1943.

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