US2581705A

US2581705A - Blade type snap acting device

Info

Publication number: US2581705A
Application number: US41348A
Authority: US
Inventors: Arthur L Riche
Original assignee: Honeywell Inc
Current assignee: Honeywell Inc
Priority date: 1948-07-29
Filing date: 1948-07-29
Publication date: 1952-01-08
Anticipated expiration: 1969-01-08

Description

Jan. 8, 1952 RlCHE 2,581,705

BLADE TYPE SNAP ACTING DEVICE Filed July 29, 1948 2 SHEETS-SHEET 1 Patented Jan. 8, 1952 2,581,705 BLADE TYPE SNAP ACTING DEVICE Arthur L. Riche, Freeport, 111., assignor, by mesne assignments, to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application July 29, 1948, Serial No. 41,348

7 Claims. (Cl. 200-67) This invention relates to snap acting devices and more particularly to snap acting switches.

An object of the invention is to provide a snap acting device of the above character with novel means for imparting a hammer blow to the components of the device during actuation thereof.

A more specific object of the invention is to provide a snap acting device of the above character having a portion free to move between preselected positions with a novel spring system comprising an auxiliary spring system in effect superimposed on a main spring system for imparting a hammer blow to the free end portion after actuation of the main spring system when the free portion is unrestrained in either preselected position and imparting a hammer blow to the free end portion to initiate movement thereof when the end portion is restrained in either position.

Another object of the invention is to provide a snap acting mechanism of the above character which is simple in construction, which is positive in its action, and which is relatively inexpensive to manufacture.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings, in which- Figure 1 is a top plan view of a snap acting switch embodying the present invention;

Fig. 2 is a side elevational view of the switch shown in Figure 1 with the components of the switch in one position of operation;

Fig. 3 is a view similar to Fig. 2 showing the position of the component parts of the switch in another position of operation;

Fig. 4 is a sectional view taken substantially along the line 4-4 of Figure 1;

Fig. 5 is a sectional view taken substantially along the line 5--5 of Figure 1;

Fig. 6 is a sectional view similar to Fig. 5 with the component parts of the switch in the operating position shown in Fig. 3;

Fig. '7 is a top plan view of a modified the invention;

Fig. 8 is a side elevational view of Fig. '7 with the components of the switch in one position of operation;

' Fig. 9 is a fragmentary view similar to Fig. 8 showing the component parts of the switch mechin another position of operation, and

Fig. 10 is a sectional view taken substantially along the line Ill-Ill of Fig. 7.

Referring now to the drawings the invention is shown embodied in a snap action switch comform of in cantilever fashion between insulating members l6 and I1, forming a part of a mounting body or. base l8. The movable contacts ll may be con.

nected to external power circuits through terminals 19 disposed between the insulating members l6 and 11. The spaced contacts l2 are mounted at the free ends of resilient leaf springs 2|. The opposite ends of the leaf springs 2| are disposed between insulating members l6 and 22' of the base I8. The spaced contacts l3 are supported at the free ends of resilient leaf springs 23. The opposite ends of the leaf springs 23 are disposed between insulating members I1 and 24 of the base 18. Stops 26 and 21 on opposite.

sides of the base l8 and in side by side relation with the resilient members 2| and 23, respectively,

are engaged by the latter members to determine the fixed position of the spaced contacts l2 and I3. The contacts l2 may be connected to external circuits through terminals 28 integral with the leaf springs 2| and extending outwardly from the base l8. In a similar fashion the contacts 13 may be connected to external power circuits,

through terminals 29 integral with the leaf springs 23 and extending outwardly from the base l8. As shown the

stops

26 and 21, insulating members 16, ll, 22 and 24, and the leaf springs 2|, 23 and I4 are held in assembled relation by screws 30 and associated nuts.

In this embodiment of the invention the driving spring system for moving the contact ll between the spaced contacts l2 and I3 is formed by a tension member 3|, a compression member 32, a compression member 33, a support member 34 for the compression member 33, the leaf springs 14 supporting the movable contacts H and an insulating member 36 interconnecting the free ends of the leaf springs i4 and carrying the support 34. Thus, the leaf springs I4, insulating member 36 and support member 34 form a unitary mounted support for compression member 33. As shown in Figure 1 the tension member 31 comprises spaced

leg portions

31 and 38. At one end the latter are mounted in cantilever fashion between an insulating member 39 and a plate 4| prising in general a driven means movable be- 66 at one side of the base I8. The o posite ends of warms means for effecting disengagement of the movable contacts II from the spaced contacts I2 and I3, respectively, with a hammer blow when the movable contacts are held in engagementwith the spaced contacts as by welds or the like. For this purpose an auxiliary spring system is in efiect superimposed on the driving spring system and is operable to disengage the contacts I from their respective fixed contacts with a hammer blow upon actuation of the auxiliary spring system. The auxiliary spring system in this embodiment of the invention is formed by the tension member 3|, the compression member 32 and the compression member 33. As shown in Figure 1 the compression member 33 is made more resilient than the support 34 by removing portions 46 on opposite sides of the compression member33 adjacent the support 34 so that the compression member 33 may be flexed to either side of the support. The compression member 32 is formed with spaced

abutments

48 and 49 shaped to engage opposite sides respectively of side portions 50. The side portions or projections 50 are rigid with the support 34 and extend outwardly therefrom toward the bridging portion 42. The side portions 50 are in generally parallel relation and are disposed on opposite sides of the compression member 33. The spacing between the

abutments

48 and 49 determines the relative position of the free end of the compression member 33 at either side of the support 34. The spacing between the abutments also forms a lost motion connection between the respective parts. For simplicity of manufacture the support 34, the compression member 33 and the side portions 50 may be formed as a single metal stamping.

The operation of the switch may be readily understood from Figs. 2 and 3. As seen in Fig. 2 the compression member 33 is at the left side of the plane of the tension member 3| and is flexed to the left of the plane of the side portions 50 and the shoulders 48 engage the side portions 50. With this position of the parts the stresses in the spring system are such as to urge the movable contacts into engagement with the contacts l3. To actuate the switch the bridging portion 42 is moved to the left from the position shown in Fig. 2. As the bridging portion 42 moves to the left the pointed end of the projection 44 is moved into a plane defined by the pointed end of the compression member 33 and the line of effective support of the leaf springs l4. Continued move ment of the bridging portion 42 carries the pointed end of the projection 44 to the left, facing Fig. 2, of the above described plane and produces a reversal of the horizontal force applied to the end of the member 33 connected with the member 32 and causes snap action of the spring system. The contacts H are thus caused to move from engagement with contacts |3 into engagement the shoulders 48 niove out of engagement with the side portions 50 through the lost motion connection formed by the spacing of the

abutments

48 and 49 and the shoulders 49 move into engagement therewith with a hammer blow. Under this condition of operation the hammer blow is imparted to the contacts after initiation of the snap movement between the contacts l3 and I2. When a weld occurs between the contacts the operation of the switch is somewhat different. Under this'condition when the bridging portion 42 carries the pointed end of the projection 44 through the plane deflned by the pointed end of the compression member 33 and the line of elfective' support of the leaf springs l4, stresses are set up which tend to urge the movable contacts out of engagement with the spaced contacts l3 into engagement with the spaced contacts l2. The weld orwelds however between the contacts may prevent actual movement. The bridging portion 42 is moved to the left to carry the pointed end of the projection 44 across the axis of unstable equilibrium (defined by a line passing through the point of interconnection between

compression members

32 and 33 and the juncture between the support 34 and the compression of the auxiliary spring system member 33) whereupon the abutments 48 move out of engagement with the side portions 58 and. the abutments 43 are moved with'a snap movement to strike the side portions 50 witha hammer blow. This breaks the weld and consequently the movable contacts move between the fixed contacts with a snap action. After actuation of the switch mechanism the component parts assume the position shown in Fig. 3. It is seen that the compression member 33 is disposed at the right of the plane of the tension member 3| and is flexed to the right of the plane of the side portions 50 and the shoulders 49 engage the side portions 58 respectively. With this position of the components the stresses in the spring systems are such as to position the support 34 so that the movable contacts I are urged into engagement with the contacts I2 with a positive pressure. The actuation of the snap spring system in the opposite direction takes place in a manner similar to that just described.

In the embodiment shown in Figs. 7 through 10 the driven means comprises mobile contacts 5| and 52 on opposite sides of the spring system and movable between

opposed contacts

53 and 54 and 56 and 51 respectively. The contacts 5| and 52 are mounted at the ends of cantilever mounted resilient members '58 and 59 respectively having their opposite ends disposed between insulating members. The

contacts

53 and 54 are mounted at the free ends of cantilever mounted

resilient leaf springs

64 and 66, respectively. The opposite ends of the

members

64 and 66 are suitably disposed between insulating members of the mounting base or support 6|. The

contacts

56 and 51 are mounted on the free ends of cantilever mounted

resilient leaf springs

61 and 68 respectively. The opposite ends of the

members

61 and 68 are suitably disposed between insulating members of the mounting base 6 The contacts 5|. 53 and 54 may be connected to external power circuits through terminals 69, II and I2 respectively projecting outwardly from a side of the mounting base 6|. The

contacts

52, 58 and 51 may be connected to external power sources through terminals 13, I4 and 16 also projectingoutwardly from the side of the mounting base. The respective leaf springs and insulating mem- 5. bars are secured together by screws 11 extending through the assembly and threaded into a mounting bracket 18.

The driving spring system in this embodiment of the invention includes a tension member 18, a compression member 8|, compression member 82 and a support 88. Thetension member 18 comprises spaced

leg portions

84 and 88. At one end the tension member is mounted in a cantilever fashion as by being disposed between suitable insulating members of the base 8| and at itgopposite end the tension member 18 is free to be moved manually or otherwise between preselected positions. The tension member is biased in this embodiment of the invention, for purposes of illustration, to form a self-retum system. the at-rest position being defined by a stop 81 mounted in cantilever fashion and disposed adjacent one side of the tension member 18 as seen in Fig. 8. In this embodiment one end of the compression member 82 is mounted in cantilever Iashion on the movable support 88 and its opposite end is in spaced relation with the free end of the tension member 18 and is free to move between preselected positions. To increase the flexibility of compression member 82 relative to the support 88 portions 88 are removed from the compression member 82 adjacent the support 83. The movable support 88 is also free to move between preselected positions and is mounted in cantilever fashion on the support 8| to extend between the

legs

88 and 88 of the tension member.

18. The compression member 8| is disposed between the free end portion of the tension member I8 and the compression member 82 and is formed with spaced

shoulders

88 and 89 respectively shaped to engage side portions 81 integral with the support 88 and in side by side relation with the compression member 82. This construction in effect results in an auxiliarly spring system, comprising the tension member 19 and the compression members 8| and 82, having an axis of unstable equilibrium being superimposed on the main spring ,system in the manner described for the embodiment shown in Figs. 1-6. For convenience in manufacturing the support 88, compression member 82, and the spaced side portions 8! may be formed as a single metal stamping.

The movable contacts 5| and 52 are connected to the spring system as by a rigid insulating member 82 mounted on the movable support 88. The rigid insulating member is formed with a central opening through which the cantilever mounted support 83 projects and the

resilient leaf springs

88 and 58 are formed with projections 98 and 96 respectively which extend through apertures spaced on opposite sides of the central opening 88 of the insulating member 92. The ends of the projections extending through the respective openings are deformed as shown in Figs. 8 and 9 to secure the component parts in assembled relation.

With the exception that the switch shown in Figs. '7 through 10 is of the self-return type the switch operates in substantially the same manner as the switch disclosed in Figs. 1-6;

I claim:

1. In a snap action device, the combination 0! a first resilient member mounted with an end portion free to move between preselected positions, means for mounting the opposite end of the first resilient member, a support movable between preselected positions, rigid spaced projections connected with and extending outwardly. from said support, a second resilient member posite sides of the projections, said first, secondv and third resilient members and said support forming a snap spring system and said first, sec-- 0nd and third resilient members forming an auxiliary snap spring system whereby movement of the point of interconnection between the first and third resilient members through a line passing through the point of interconnection betweensaid second and third resilient members and the eilective mounting for said support urges the support to move between its preselected position with a snap movement and movement of the point of interconnection between the first and third resilient members through a line joining the point of interconnection between the second and third resilient members and the juncture between the second resilient member and the support moves said abutments relative to the projections to impart a hammer blow to said support.

2. In a snap acting device, the combination of spaced fixed contacts, a movable contact alternately engageable with said spaced contacts, a tension member having one end mounted in cantilever fashion and an end portion free to move between opposed positions, a mounted support movable between preselected positions, at least one rigid portion extending outwardly from said support, a first compression member mounted on said support adjacent said rigid portion and being movable to either side thereof, a second compression member disposed between and in-- terconnected with said tension member and the first compression member, said second compression member having spaced abutments engageable with said rigid portion of the movable support to form a lost motion connection therewith, said tension member, said first and second compression members and said support forming a first spring system, said tension member and said first and second compression members forming a second spring system and means rigidly connecting said movable contact with said support whereby movement of the point of interconnection between the tension member and the second compression member through a line passing through the point of interconnection between the first and second compression members and the effective point of mounting of said support urges said movable contact to move between the fixed contacts with a snap action and movement of the point of interconnection between the tension member and the second compression member through a line passing through the point of interconnection between the first and second compression members and the juncture between the first compression member and the support moves said abutments through the lost motion connection to strike said rigid portion a hammer blow.

3. In a snap acting device, the combination of a first resilient member having an end free to move between preselected positions, means for mounting the opposite end of the first resilient ,member in cantilever fashion, a second resilient member having. an end in. spaced relation with the free end of thefirst resilient member, a support formountingthetopposite endoi the second resilient member in cantilever fashion and movable'between preselected positions, said support comprising spaced relatively rigid side portions to be passed bysaid second resilient member as it moves between its preselected positions and disposed on opposite sides of said second resilient member, a third resilient member disposed between the first resilient member and the second resilient member and having. spaced abutments engageable alternately with said side portions of the support, said first, second and third jresilient members and. said support forming a. first spring system, said first, second and third resilient members forming. a second spring system, said abutments being spaced to provide a lost motion connection :between the third resilient member and the spacedrigid side portions whereby movement of the point of interconnection be;- tween the first and third, resilient members through a line passing through the point of interconnection betweenthe second and third resilient members and the effective point of mounting of the support urges said support between preselected positions with a snap action and movement of the point of interconnection between said first and third resilient members through a line passing t ough the connection between the second and third resilient members and the juncture between the support and the second resilient member drives said abutments into engagement with the side portions with a hammer blow.-

4. In a snap acting device, the combination of a tension member having a free end portion movable between preselected positions, means for mounting the opposite end of said tensionmember, a first compression member having a free end portion movable between preselected position and disposed in spaced relation to said free end. portion of the tension member, movable means for supporting the opposite end of said first compression member, a second compression member disposed between said free end of the first compression member and the free end portion of the tension member, actuated means rigid with said movable'support means movable in unison therewith between preselected positions with a snap action, said tension and said first and second compression members and said support forming a first overcenter spring system and said tension and said first and second compression members forming a second overcenter spring system and a lost motion connection between said movable, support and said second compression member whereby movement of one of the members through the overcenter position of the first spring system urges said movable support to move between its preselected positions and movement of said member through the overcenter position of the --second spring system causes the second compression member to engage the movable support through the lost motion connection with a hammer blow action.

5. In a snap acting device, the combination of spaced contacts, a movable contact engageable alternately with said spaced contacts, a tension member having one end mounted in cantilever fashion and an end portion movable between preselected positions, a support movable. between preselected positions, a. flexible compression member-mounted on saidsupport and having an aeamos.

. 8 I end in spaced relation with the free end portion of said tension'member movable, bet nzv eee lected positions on oppos te sides of the plane oi;-

said support, a second compressionmember disposed between said tension member and said first compression member, a lost motion connectionbetween said second compression member and said support, said tension member, said first and second compression members and said support forming a first snap spring system and said tension member and said first and second eompression members forming a second snap spring system, means rigidly connecting said movable contact with said support whereby movement of said end portion of the tension member through.

I a line passing through the point oflnterconnection between the first and second compression members and the eilective point of mounting of the support urges said movable contact between the fixed contacts and movement of the end por-' tion of the tension member through a line passing through the point of interconnection between the first and second compression members and the juncture between the first compression member and the support moves said second compression member relative to the support through the lost motion connection to en age the support with a hammer blow to drive said movable con-' tacts between the spaced contacts with a hammer blow snap action.

6. In a snap acting device, the combination of a first resilient member having an end free to move between, opposed positions, means for mounting the first resilient member in a cantilever manner, a movable mounted support, a second resilient member mounted on said support and having an end in spaced relation with the free end of the first resilient member and movable to either side of said support, a third resilient member disposed between the free ends of the first and second resilient members to form with said first and second resilient members and said support a snap spring system and to form with said first and second resilient members a second snap spring system, a lost motion connection between saidmovable support and said third resilient member whereby movement of said free end of the first resilient member through a line passing through the point of interconnection between the second resilient member and the third resilient member and the efiective.

resilient member and the support causes the third resilient member to engage the support with a hammer blow.

'7. In a snap action device, the combination of a tension member mounted to have an end portion movable between preselected positions, a support movable between preselected positions, a first compression member mounted on said support and having a free end in spacedrelation to said end portion of the tension member and movable to either side of the support, a second compression member disposed between said free end of said first compression member and the end portion of the tension member, said tension mem ber, said first and second compression members and said support forming a first snap spring system, said tension member and said first and sec.- ond compression members forming a second snap- 2,681,705 9 10 spring system, driven means connected to said REFERENCES CITED movable support and mwable between prese' The followin references are of record in the lected positions with a snap action in unison with me of this paint: said movable support when the tension member moves through the axis of maximum stress of 5 UNITED STATES PATENTS the first spring system and a lost motion con- Number Name Date nection between one of the compression members Re. 17,646 Johnsson Apr. 22, 1930 and the movable support for imparting a h m- 2,237,705 Kohl Apr. 8, 1941 mer blow to said movable support when the ten- 2,414,778 Tratsch Jan. 21, 1947 sion member moves through an axis of maxim m 10 2,425,159 Meyer Aug. 5, 1947 stress of the second spring system. 2,439,747 Nelson Apr. 13, 1948 ARTHUR L. RICHE.