CA1239434A - Microswitch - Google Patents
MicroswitchInfo
- Publication number
- CA1239434A CA1239434A CA000406819A CA406819A CA1239434A CA 1239434 A CA1239434 A CA 1239434A CA 000406819 A CA000406819 A CA 000406819A CA 406819 A CA406819 A CA 406819A CA 1239434 A CA1239434 A CA 1239434A
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- Canada
- Prior art keywords
- lever
- contact
- insulating base
- actuating
- movable contact
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
ABSTRACT
A microswitch comprises an insulating base, fixed contacts secured on the insulating base, a movable contact adapted for selectively contacting the fixed contacts, an actuating member, and means for shifting the movable contact by the use of the actuating member. The means for shifting the movable contact includes an actuating lever, an intermediate lever, a flat spring, and a contact lever all connected in series with one another, the actuating and the contact levers being pivotally connected to the insulating base, the ends of the intermediate lever and of the flat spring being connected with one another and bearing up against a limit stop, and the contact lever having a free end whereon the movable contact is located. The flat spring is connected with the end of the contact lever opposite to the free end thereof on which the limit stop and the movable contact are located, and the contact lever is connected with the insulating base at the middle portion thereof between the movable contact and the point of connection of the ends of the contact lever and the flat spring.
In comparison with prior art microswitches this micro-switch has a small differential stroke and high sensitivity.
A microswitch comprises an insulating base, fixed contacts secured on the insulating base, a movable contact adapted for selectively contacting the fixed contacts, an actuating member, and means for shifting the movable contact by the use of the actuating member. The means for shifting the movable contact includes an actuating lever, an intermediate lever, a flat spring, and a contact lever all connected in series with one another, the actuating and the contact levers being pivotally connected to the insulating base, the ends of the intermediate lever and of the flat spring being connected with one another and bearing up against a limit stop, and the contact lever having a free end whereon the movable contact is located. The flat spring is connected with the end of the contact lever opposite to the free end thereof on which the limit stop and the movable contact are located, and the contact lever is connected with the insulating base at the middle portion thereof between the movable contact and the point of connection of the ends of the contact lever and the flat spring.
In comparison with prior art microswitches this micro-switch has a small differential stroke and high sensitivity.
Description
:~3~3~
The present invention relates to a micro switch use-fur as a limit switch in automated control and protection sign nailing systems in electric drives of machines and mechanisms.
The invention will be illustrated with reference -to embodiments thereof which are represented in the accompanying drawings, wherein:
Figs. 1 and 2 show a mechanical diagram of a prior art micro switch in two extreme positions of an actuating lever;
Fig 3 shows a mechanical diagram of another prior art micro switch;
Fig. 4 shows a mechanical diagram of one more prior art micro switch;
Figs. 5 and 6 show a mechanical diagram of a micro-switch constructed in accordance with the invention, thus-treating two extreme positions of the actuating link;
Fig. 7 shows a modification of the micro switch of the invention, general view;
Fig. 8 is a detailed axonometric view of the micro-switch shown in Fig. 7;
Fig. 9 is another modification of the micro switch of the invention, general view;
Fig. 10 is a detailed axonometric of the micro-switch shown in Fig. 9.
Fig. 11 shows a further modification of the micro-switch of the invention, general view; and I ..~ ,..
- ... ,._ ~L~3~3~
figure 12 illustrates means for shifting movable contacts, top view.
The precision of operation of automatic lines and also control systems for technological processes is much dependent upon the sensitivity of the micro switches employed, which must provide for the precision of transmitted informal lion. It is very difficult in practice to correct the errors made by micro switches.
To actuate movable contacts in micro switches, metal plates are preferably used which respond to temperature or pressure and which are subject only to insignificant bending under tension or compression. Therefore, one of the main characteristics of micro switches is sensitivity defined by the length of the path of an actuating link motion, i.e.
by its differential stroke (the shorter the path required for shifting a movable contact in a micro switch the higher its sensitivity).
Known in the art is a micro switch (see, for example, US. Patent No. 2,72g,714, Nat. Of. 200-67) comprising an insulating base 1', fixed contacts' secured on this base 1', a movable contact 4' adapted to selectively contact the fixed contacts 2' and 3', and means for shifting I
- lo -":`''~' the movable contact 4' by the use of' an actuating member.
The means or Chattanooga the movable contact includes an actuating lever I' and an intermediate lever 6' connected with one another a Islet spurn and a con-tact lever 8'.
The actuating end -the contact levers and 8 t are con-netted by -their end in a single point on -the insult in base I 'Lowe movable contact it it mounts on -the opt posit tree end of the contact lever I' whose middle port lion is connected with an end of the slat spring 7'. 'the other end ox the Lotte spring 7' is connected with an end ox -the intermediate lever 6' and when in its extreme pox sessions it bears up against a Unit stop 9' wormed on the insulating base 1'. 'I've other end ox the intermediate to-Yen 6' is connected with the end ox -the actuating lever 5' which is opposite to the end connected to the insulate in base 1'.
In the initial position Owe the micro switch the pro-liminarily compressed sprint 7' acts Upon the contact levy or it 3 which is connected with i-t, with a force P (see FIG. 1).
I've contact pressure is equal:
Pi = P singe where it an angle ox inclination between -the inter-mediate lever G' and the spring 7'.
Roy actuating lever moves unwire the action of an external force I, and the intermediate lever 6' changes its position with respect to the spring 7'0 .-"'' I
As the actuating lever 5' moves to the position ox operation (when point A -takes position Allah the spring 7' is compressed the force P increases till -the value P
and thy con-tact pressure Pi somewhat increases -to Pal = Pi singe (FIG. 2).
As the point A crosses the line OIL the unstable pox session of -the spring 75 a line I I, shifting the contacts 4' takes place at the inherent speed of motion With further motion of the actuating lever 5' point A reaches the final position A Go I
When the external force F is removed prom the actual-in lever 5', all the levers ox -the means con chutney the lovable contacts I' tend to return -to their initial position.
When the point A ox' the actuation lever 5' crosses the line IT the line of the unstable switched post on ox -the spring I i.e. when the point A reaches the position ox A, the reversal shirt ox the movably con--teats 4 I takes place.
As con be seen prom the description the con-tact pressure in the micro switch is not reduced below the no-final value and is even slightly increased with the motion ox the actuating lever 51 to the position ox operation.
'Jo provide o'er chutney -the contacts 4' in such micro switch the surfaces dying tile motion ox the in-termedi~te lever in the lirllit stop must be located beyond the area defined by the lines of the position ox the con tact lever 8' in the initial and in the slotted positions, "
39g~
rho provide the shortest differential stroke ox the actuating lever 5' that is possible in such microswi-tch9 the spring 7' must be mixed in -the middle portion ox the contact lever 8', and the loyalty stop 9' mutt ye located as close to -the movable contacts 4' as possible.
The differential stroke ox -the actuating lever 5' in the point A is equal to LA = H 2 oh where H = distance between the chelated possession the movable contact 4' h = magnitude ox the stroke of the actuating, lever 5' 'the value of the stroke, oh, of the actuating lever 5' is calculated prom the relation:
H It oh I 4 AL L
then : H HAL
L =
where L is a horizontal projection ox the distance prom -the axis passing through the contacts 2' 5 3', to the point O of connection ox the spring 7' with the contact lever 8' L is a horizontal projection ox the displacement ox the point prom the point O of the connect Shirley ox' the spring I with -the contact lever 8/
......
required to insure the instantaneous shut of the contacts 4'0 The differential stroke of toe actuating; lever S' in -the puerility of application ox the force F is equal to:
/ H 3 Ho 2 F l 2 2 L Lo where Lo, Lo are horizontal projections ox the length of the actuating lever 5' aloud of its portion prom the point ox the force F application to the point Al of its connection with -the insulation base l'.
Another embodiment ox -the ulicroswi-tch disclosed in same US. Patent No. 2,7~9,714 also comprises an ins-feting base l" (JIG. iced corltacts 2", 3" secured on the insulating base 1'1, a lovable contact 4~1 adapted to so-electively contact the fixed contacts it', 3", and means or shifting the lovable con-tact 4" by the use of an actuating member, which means includes an actuating and an interim-Dwight levers I 6" connected in series with one another, a slat sprint 7", end a contact lever 8", and also a limit stop 9t1 formed on the insulatirlg base if' end located boy-on the area derailed by the lines of the positions ox the contact fever 8" in the initial an the shifted positions.
However, in this ~nicroswitch~ the slat spring 7-t is con-equated not with the middle portion ox the contact lever 8"
as it was in the previous ~icroswitch but with the end ox the contact lever Kit on which the movable contact 4" is mounted. The length ox the contact lever 8" is equal to Lo *I and the differential stroke ox the actuating lever or; at -the point and at -the point OX application ox owls I is equal to L = E
I Lo I, = H Lo ( 2 ) Known in the art is also micro switch (see US.
Patent No 3,228,523) which like the previous micros wit-ekes comprises an insulating base 1"1, fixed contacts I
and 3"' secured -to said base a movable contact 4"', all Illeatl9 foil shi~tirl~, the movable contact I in wish means an actuating a intermediate, a spring and a contact to-Yens 5"', I 7"' and 8"', respectively, are connected in series with one another (see FIG. 4).
limit stop 9"9 is located in this micro switch err the axis, Al I rotation ox the actuating and the contact lever I I he distance, Hi, between the Sly-faces in the limit stop 9"' dying the stroke of' the in--termediate lever can be short, Leo shorter than the disk Tunis I, between the contacts 2"', 3"', unlike that in bye previous microswi-tclles.
Roy value I Hi is governed by the angle and by the rate ox the spring 7"' (i.e. by the value of P), which define the contact pressure since Pi = P2sin I
The di~ferelltial stroke ox the actuating lever eta the onto A is equal to:
'.~
PA = 2 hi.
the value ox hi is found from the relation:
rip - H
hi . . ....... .
Hence (H Ho L
Lo h 'thus (H + E
L A = En he differential stroke of the actuating, lever 5"' at the point of application ox force F is easily to [ (H Hi) Lo -2 I
As can be seen prom comparison of` the worms (2) 7 (3), the dif~exential stroke of' the actuating lever 5"' in this micro switch shown it JIG. 4 is somewhat staller than in tune previous one shown in FIG. 3 since H Hi I 3II.
I 2 , hence -3 CC YE
In the known ~icroswitches shown in JIGS 1-4, -the differential stroke of' toe actuating lever at the point A
is considerable, wnicn reduces their sensitivity.
The present invention provides a micro switch wherein the arrangement of components in means for shift-'`~
:
I
in movable contacts would allow the differential stroke of an actuating link -to be considerably decreased at a constant contact pressure, thus considerably increasing the sensitivity of a micro switch.
According to the present invention there is provided a micro switch comprising an insulating base; at least one fixed contact secured -to said insulating base; a movable contact engage in the fixed contact; means for shifting the movable contact, including an actuating lever, an intermediate lever, a leaf spring and a contact lever, one end of which carries the movable contact, the actuating lever being secured at one end thereof to the insulating base for angular turning relative there-to, the contact lever being secured to the insulating base for angular turning relative thereto, the first ends of the intermediate lever and -the leaf spring being interconnected for angular turn-in and interacting with the contact lever by means of limelight stops, -the other end of the intermediate lever being connected to the end of the actuating lever opposite to the end secured to the insulating base, and the other end of the leaf spring being con-netted to the contact lever for angular turning relative thereto, characterized in that the other end of -the leaf spring is con-netted to the end of the contact lever opposite to the end to which the movable contact is secured, the connecting point of the contact lever to the insulating base being located between the middle portion of -the length of the contact lever and the con-netting point of the end of the leaf spring secured thereto, which is not connected to the intermediate lever, and the con-netting point of the ends of the intermediate lever and the leaf spring interacting, by means of the limit stops, with the contact lever between the connecting point of the movable contact to the leaf spring and the connecting point of the contact lever to the insulating base.
The combination of the flat spring with -the contact lever, the combination of the contact lever with the insulating I: - 8 -base, and location of the limit stop on the contact lever allow -the differential stroke of the actuating link to be considerably decreased and the sensitivity of the micro switch to be signify-gently increased.
;
\ - pa -Referring to Figs. 5 to 12, a micro switch comprises an insulating base 1, fixed contacts 2,3 secured on this insulating base 1, a movable contact 4 adapted for select lively contacting the fixed contacts 2,3, an actuating member 5, and means for shifting the movable contact 4 by the use of the actuating member 5.
The means for shifting -the movable contacts 4 in-eludes an actuating lever 6, an intermediate lever 7, a flat spring I and a contact lever 9. One end 10 of the actuating lever 6 is pivotal connected to the insulating base 1.
.. _ 9 _ ; ' Jo Jo The other end 11 of the actuating lever 6 is con-netted with the intermediate lever 7. The movable contact 4 is mounted on the free end 12 of the contact lever 9.
Ends 13 and 14 of the intermediate lever 7 and the flat spring, respectively, are connected with each other. The contact lever 9 is pivotal connected to the insulating base and is connected with an end 15 of the flat spring 8.
In accordance with the invention, the end 15 of the flat spring 8 is connected with the end 16 of the con-tact lever 9 which is opposite to the end on which the movable contact is located. A limit stop 17 is located on the free end of the contact lever 9, which limit stop rest trials the motion of the end 13 of the intermediate lever 7. The contact lever 9 is connected with -the insulating base 1 by : 25 I'' .
I I
its middle portion between the movable portion 4- and the point of connection of -the ends 16 and 15 ox -the contact lever 9 and -the slat spring 7 Such arrangement allows the differential stroke ox the actuating link -to be considerably decreased and tiler-fore the seLlsi-tivity of the micro switch -to be considerably increased in comparison with prior art micro switches.
JIGS 7-12 illiterate possible modifications of tile micro switch of the invention and the arrangement of the to-Yens arid -the slat spring.
Such ~icroswitch operates as owls.
In -ale initial piston owe toe micro switch the pro-liminaril.~ compressed spring 8 acts with the ours P upon the intermediate lever see FIGS 5-6).
he con-tact pressure Pi consists Owe two components:
Pi Pi + 3 where Pi _ P ionic Pi = I sin is an angle of inclination between the triter mediate lever 7 and the sprint 8 is an angle of inclirla-tion between the spring 8 end -the lever L, is a horizontal projection of the length ox the contact lever 9 prom -the point 0, of its connection with -the insulating base 1 to -the point ox connectiorl of the contact :
~r2~3~43~-~
lever 9 with the slat spring 8 L is a horizontal projection owl tune length of -the con-tact lever 9 Lrocl-the point 0 to -the end 12 on which the movable contact 4 is so-cured Under the action ox the external force F, which no-aches -tune value I the actuation lever 6 moves in -the direction ox -this ours, and the intermediate lever 7 change en its position and compresses tune spring 8.
As the point A reaches the position Al, the contact prosier it somewhat increased since tile force P increases till the value owe P' (see lug. 6) under -the aC-~iorl ox the collapsed spring I.
Pi = Pi 2 With further motion OIL the actuating lever 6 and with crossing the line I-I9 the line ox unstable position, by the point A, the shirt ox the movable contact 4 takes place a-t an inherent speed of motion.
'Lowe di~:Eerential stroke ox the actuating lever 6 at the pullout A (point out' connection of the actuating and ox the intermediate levers 6 and 7) it equal -to the distance : between the points Alp A see FIG 5 A ho 2 ho he stroke ho it found Rome the relation :
I
Jo ho ill Lo fence Lo ) where Lo is a horizontal projection ox the magnitude of the point A displacement true stroke ho is found prom the relation 3 _ 2 I
pence Ho ho = AL
:
Thus _ ~(~ Lo Lo) Hl7 L
A L L
The differential stroke ox -the actuating lever 6 at the joint of a~Jlica-tio~ ox the force equals Ho I + I + Hi A 2 1 L
F L L L L
where and Lo _ a horizontal projection ox -the length of -the actuating lever 6 and a horn-: zontal projection ox its portion prom the point ox application ox the force I Lo F to the point of its connection on the insulating base 1, Since in practice I Ox Lo 0.02~, and Ho EYE, thus AYE- J lie.
: wherefore, the differential stroke of the actuating link in Tess micro switch comparing the expressions I
and (4) a it approximately -ten times smaller than in the prior art micro switch shown in FIG. 4 . .
:
''
The present invention relates to a micro switch use-fur as a limit switch in automated control and protection sign nailing systems in electric drives of machines and mechanisms.
The invention will be illustrated with reference -to embodiments thereof which are represented in the accompanying drawings, wherein:
Figs. 1 and 2 show a mechanical diagram of a prior art micro switch in two extreme positions of an actuating lever;
Fig 3 shows a mechanical diagram of another prior art micro switch;
Fig. 4 shows a mechanical diagram of one more prior art micro switch;
Figs. 5 and 6 show a mechanical diagram of a micro-switch constructed in accordance with the invention, thus-treating two extreme positions of the actuating link;
Fig. 7 shows a modification of the micro switch of the invention, general view;
Fig. 8 is a detailed axonometric view of the micro-switch shown in Fig. 7;
Fig. 9 is another modification of the micro switch of the invention, general view;
Fig. 10 is a detailed axonometric of the micro-switch shown in Fig. 9.
Fig. 11 shows a further modification of the micro-switch of the invention, general view; and I ..~ ,..
- ... ,._ ~L~3~3~
figure 12 illustrates means for shifting movable contacts, top view.
The precision of operation of automatic lines and also control systems for technological processes is much dependent upon the sensitivity of the micro switches employed, which must provide for the precision of transmitted informal lion. It is very difficult in practice to correct the errors made by micro switches.
To actuate movable contacts in micro switches, metal plates are preferably used which respond to temperature or pressure and which are subject only to insignificant bending under tension or compression. Therefore, one of the main characteristics of micro switches is sensitivity defined by the length of the path of an actuating link motion, i.e.
by its differential stroke (the shorter the path required for shifting a movable contact in a micro switch the higher its sensitivity).
Known in the art is a micro switch (see, for example, US. Patent No. 2,72g,714, Nat. Of. 200-67) comprising an insulating base 1', fixed contacts' secured on this base 1', a movable contact 4' adapted to selectively contact the fixed contacts 2' and 3', and means for shifting I
- lo -":`''~' the movable contact 4' by the use of' an actuating member.
The means or Chattanooga the movable contact includes an actuating lever I' and an intermediate lever 6' connected with one another a Islet spurn and a con-tact lever 8'.
The actuating end -the contact levers and 8 t are con-netted by -their end in a single point on -the insult in base I 'Lowe movable contact it it mounts on -the opt posit tree end of the contact lever I' whose middle port lion is connected with an end of the slat spring 7'. 'the other end ox the Lotte spring 7' is connected with an end ox -the intermediate lever 6' and when in its extreme pox sessions it bears up against a Unit stop 9' wormed on the insulating base 1'. 'I've other end ox the intermediate to-Yen 6' is connected with the end ox -the actuating lever 5' which is opposite to the end connected to the insulate in base 1'.
In the initial position Owe the micro switch the pro-liminarily compressed sprint 7' acts Upon the contact levy or it 3 which is connected with i-t, with a force P (see FIG. 1).
I've contact pressure is equal:
Pi = P singe where it an angle ox inclination between -the inter-mediate lever G' and the spring 7'.
Roy actuating lever moves unwire the action of an external force I, and the intermediate lever 6' changes its position with respect to the spring 7'0 .-"'' I
As the actuating lever 5' moves to the position ox operation (when point A -takes position Allah the spring 7' is compressed the force P increases till -the value P
and thy con-tact pressure Pi somewhat increases -to Pal = Pi singe (FIG. 2).
As the point A crosses the line OIL the unstable pox session of -the spring 75 a line I I, shifting the contacts 4' takes place at the inherent speed of motion With further motion of the actuating lever 5' point A reaches the final position A Go I
When the external force F is removed prom the actual-in lever 5', all the levers ox -the means con chutney the lovable contacts I' tend to return -to their initial position.
When the point A ox' the actuation lever 5' crosses the line IT the line of the unstable switched post on ox -the spring I i.e. when the point A reaches the position ox A, the reversal shirt ox the movably con--teats 4 I takes place.
As con be seen prom the description the con-tact pressure in the micro switch is not reduced below the no-final value and is even slightly increased with the motion ox the actuating lever 51 to the position ox operation.
'Jo provide o'er chutney -the contacts 4' in such micro switch the surfaces dying tile motion ox the in-termedi~te lever in the lirllit stop must be located beyond the area defined by the lines of the position ox the con tact lever 8' in the initial and in the slotted positions, "
39g~
rho provide the shortest differential stroke ox the actuating lever 5' that is possible in such microswi-tch9 the spring 7' must be mixed in -the middle portion ox the contact lever 8', and the loyalty stop 9' mutt ye located as close to -the movable contacts 4' as possible.
The differential stroke ox -the actuating lever 5' in the point A is equal to LA = H 2 oh where H = distance between the chelated possession the movable contact 4' h = magnitude ox the stroke of the actuating, lever 5' 'the value of the stroke, oh, of the actuating lever 5' is calculated prom the relation:
H It oh I 4 AL L
then : H HAL
L =
where L is a horizontal projection ox the distance prom -the axis passing through the contacts 2' 5 3', to the point O of connection ox the spring 7' with the contact lever 8' L is a horizontal projection ox the displacement ox the point prom the point O of the connect Shirley ox' the spring I with -the contact lever 8/
......
required to insure the instantaneous shut of the contacts 4'0 The differential stroke of toe actuating; lever S' in -the puerility of application ox the force F is equal to:
/ H 3 Ho 2 F l 2 2 L Lo where Lo, Lo are horizontal projections ox the length of the actuating lever 5' aloud of its portion prom the point ox the force F application to the point Al of its connection with -the insulation base l'.
Another embodiment ox -the ulicroswi-tch disclosed in same US. Patent No. 2,7~9,714 also comprises an ins-feting base l" (JIG. iced corltacts 2", 3" secured on the insulating base 1'1, a lovable contact 4~1 adapted to so-electively contact the fixed contacts it', 3", and means or shifting the lovable con-tact 4" by the use of an actuating member, which means includes an actuating and an interim-Dwight levers I 6" connected in series with one another, a slat sprint 7", end a contact lever 8", and also a limit stop 9t1 formed on the insulatirlg base if' end located boy-on the area derailed by the lines of the positions ox the contact fever 8" in the initial an the shifted positions.
However, in this ~nicroswitch~ the slat spring 7-t is con-equated not with the middle portion ox the contact lever 8"
as it was in the previous ~icroswitch but with the end ox the contact lever Kit on which the movable contact 4" is mounted. The length ox the contact lever 8" is equal to Lo *I and the differential stroke ox the actuating lever or; at -the point and at -the point OX application ox owls I is equal to L = E
I Lo I, = H Lo ( 2 ) Known in the art is also micro switch (see US.
Patent No 3,228,523) which like the previous micros wit-ekes comprises an insulating base 1"1, fixed contacts I
and 3"' secured -to said base a movable contact 4"', all Illeatl9 foil shi~tirl~, the movable contact I in wish means an actuating a intermediate, a spring and a contact to-Yens 5"', I 7"' and 8"', respectively, are connected in series with one another (see FIG. 4).
limit stop 9"9 is located in this micro switch err the axis, Al I rotation ox the actuating and the contact lever I I he distance, Hi, between the Sly-faces in the limit stop 9"' dying the stroke of' the in--termediate lever can be short, Leo shorter than the disk Tunis I, between the contacts 2"', 3"', unlike that in bye previous microswi-tclles.
Roy value I Hi is governed by the angle and by the rate ox the spring 7"' (i.e. by the value of P), which define the contact pressure since Pi = P2sin I
The di~ferelltial stroke ox the actuating lever eta the onto A is equal to:
'.~
PA = 2 hi.
the value ox hi is found from the relation:
rip - H
hi . . ....... .
Hence (H Ho L
Lo h 'thus (H + E
L A = En he differential stroke of the actuating, lever 5"' at the point of application ox force F is easily to [ (H Hi) Lo -2 I
As can be seen prom comparison of` the worms (2) 7 (3), the dif~exential stroke of' the actuating lever 5"' in this micro switch shown it JIG. 4 is somewhat staller than in tune previous one shown in FIG. 3 since H Hi I 3II.
I 2 , hence -3 CC YE
In the known ~icroswitches shown in JIGS 1-4, -the differential stroke of' toe actuating lever at the point A
is considerable, wnicn reduces their sensitivity.
The present invention provides a micro switch wherein the arrangement of components in means for shift-'`~
:
I
in movable contacts would allow the differential stroke of an actuating link -to be considerably decreased at a constant contact pressure, thus considerably increasing the sensitivity of a micro switch.
According to the present invention there is provided a micro switch comprising an insulating base; at least one fixed contact secured -to said insulating base; a movable contact engage in the fixed contact; means for shifting the movable contact, including an actuating lever, an intermediate lever, a leaf spring and a contact lever, one end of which carries the movable contact, the actuating lever being secured at one end thereof to the insulating base for angular turning relative there-to, the contact lever being secured to the insulating base for angular turning relative thereto, the first ends of the intermediate lever and -the leaf spring being interconnected for angular turn-in and interacting with the contact lever by means of limelight stops, -the other end of the intermediate lever being connected to the end of the actuating lever opposite to the end secured to the insulating base, and the other end of the leaf spring being con-netted to the contact lever for angular turning relative thereto, characterized in that the other end of -the leaf spring is con-netted to the end of the contact lever opposite to the end to which the movable contact is secured, the connecting point of the contact lever to the insulating base being located between the middle portion of -the length of the contact lever and the con-netting point of the end of the leaf spring secured thereto, which is not connected to the intermediate lever, and the con-netting point of the ends of the intermediate lever and the leaf spring interacting, by means of the limit stops, with the contact lever between the connecting point of the movable contact to the leaf spring and the connecting point of the contact lever to the insulating base.
The combination of the flat spring with -the contact lever, the combination of the contact lever with the insulating I: - 8 -base, and location of the limit stop on the contact lever allow -the differential stroke of the actuating link to be considerably decreased and the sensitivity of the micro switch to be signify-gently increased.
;
\ - pa -Referring to Figs. 5 to 12, a micro switch comprises an insulating base 1, fixed contacts 2,3 secured on this insulating base 1, a movable contact 4 adapted for select lively contacting the fixed contacts 2,3, an actuating member 5, and means for shifting the movable contact 4 by the use of the actuating member 5.
The means for shifting -the movable contacts 4 in-eludes an actuating lever 6, an intermediate lever 7, a flat spring I and a contact lever 9. One end 10 of the actuating lever 6 is pivotal connected to the insulating base 1.
.. _ 9 _ ; ' Jo Jo The other end 11 of the actuating lever 6 is con-netted with the intermediate lever 7. The movable contact 4 is mounted on the free end 12 of the contact lever 9.
Ends 13 and 14 of the intermediate lever 7 and the flat spring, respectively, are connected with each other. The contact lever 9 is pivotal connected to the insulating base and is connected with an end 15 of the flat spring 8.
In accordance with the invention, the end 15 of the flat spring 8 is connected with the end 16 of the con-tact lever 9 which is opposite to the end on which the movable contact is located. A limit stop 17 is located on the free end of the contact lever 9, which limit stop rest trials the motion of the end 13 of the intermediate lever 7. The contact lever 9 is connected with -the insulating base 1 by : 25 I'' .
I I
its middle portion between the movable portion 4- and the point of connection of -the ends 16 and 15 ox -the contact lever 9 and -the slat spring 7 Such arrangement allows the differential stroke ox the actuating link -to be considerably decreased and tiler-fore the seLlsi-tivity of the micro switch -to be considerably increased in comparison with prior art micro switches.
JIGS 7-12 illiterate possible modifications of tile micro switch of the invention and the arrangement of the to-Yens arid -the slat spring.
Such ~icroswitch operates as owls.
In -ale initial piston owe toe micro switch the pro-liminaril.~ compressed spring 8 acts with the ours P upon the intermediate lever see FIGS 5-6).
he con-tact pressure Pi consists Owe two components:
Pi Pi + 3 where Pi _ P ionic Pi = I sin is an angle of inclination between the triter mediate lever 7 and the sprint 8 is an angle of inclirla-tion between the spring 8 end -the lever L, is a horizontal projection of the length ox the contact lever 9 prom -the point 0, of its connection with -the insulating base 1 to -the point ox connectiorl of the contact :
~r2~3~43~-~
lever 9 with the slat spring 8 L is a horizontal projection owl tune length of -the con-tact lever 9 Lrocl-the point 0 to -the end 12 on which the movable contact 4 is so-cured Under the action ox the external force F, which no-aches -tune value I the actuation lever 6 moves in -the direction ox -this ours, and the intermediate lever 7 change en its position and compresses tune spring 8.
As the point A reaches the position Al, the contact prosier it somewhat increased since tile force P increases till the value owe P' (see lug. 6) under -the aC-~iorl ox the collapsed spring I.
Pi = Pi 2 With further motion OIL the actuating lever 6 and with crossing the line I-I9 the line ox unstable position, by the point A, the shirt ox the movable contact 4 takes place a-t an inherent speed of motion.
'Lowe di~:Eerential stroke ox the actuating lever 6 at the pullout A (point out' connection of the actuating and ox the intermediate levers 6 and 7) it equal -to the distance : between the points Alp A see FIG 5 A ho 2 ho he stroke ho it found Rome the relation :
I
Jo ho ill Lo fence Lo ) where Lo is a horizontal projection ox the magnitude of the point A displacement true stroke ho is found prom the relation 3 _ 2 I
pence Ho ho = AL
:
Thus _ ~(~ Lo Lo) Hl7 L
A L L
The differential stroke ox -the actuating lever 6 at the joint of a~Jlica-tio~ ox the force equals Ho I + I + Hi A 2 1 L
F L L L L
where and Lo _ a horizontal projection ox -the length of -the actuating lever 6 and a horn-: zontal projection ox its portion prom the point ox application ox the force I Lo F to the point of its connection on the insulating base 1, Since in practice I Ox Lo 0.02~, and Ho EYE, thus AYE- J lie.
: wherefore, the differential stroke of the actuating link in Tess micro switch comparing the expressions I
and (4) a it approximately -ten times smaller than in the prior art micro switch shown in FIG. 4 . .
:
''
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A microswitch comprising an insulating base; at least one fixed contact secured to said insulating base; a mov-able contact engaging the fixed contact; means for shifting the movable contact, including an actuating lever, an intermediate lever, a leaf spring and a contact lever, one end of which car-ries the movable contact, the actuating lever being secured at one end thereof to the insulating base for angular turning rela-tive thereto, the contact lever being secured to the insulating base for angular turning relative thereto, the first ends of the intermediate lever and the leaf spring being interconnected for angular turning and interacting with the contact lever by means of limit stops, the other end of the intermediate lever being connected to the end of the actuating lever opposite to the end secured to the insulating base, and the other end of the leaf spring being connected to the contact lever for angular turning relative thereto, characterized in that the other end of the leaf spring is connected to the end of the contact lever opposite to the end to which the movable contact is secured, the connecting point of the contact lever to the insulating base being located between the middle portion of the length of the contact lever and the connecting point of the end of the leaf spring secured thereto, which is not connected to the intermediate lever, and the connecting point of the ends of the intermediate lever and the leaf spring interacting, by means of the limit stops, with the contact lever between the connecting point of the movable contact to the leaf spring and the connecting point of the con-tact lever to the insulating base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000406819A CA1239434A (en) | 1982-07-07 | 1982-07-07 | Microswitch |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000406819A CA1239434A (en) | 1982-07-07 | 1982-07-07 | Microswitch |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1239434A true CA1239434A (en) | 1988-07-19 |
Family
ID=4123170
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000406819A Expired CA1239434A (en) | 1982-07-07 | 1982-07-07 | Microswitch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1239434A (en) |
-
1982
- 1982-07-07 CA CA000406819A patent/CA1239434A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |