US3496311A - Pushbutton switch - Google Patents

Pushbutton switch Download PDF

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Publication number
US3496311A
US3496311A US663076A US3496311DA US3496311A US 3496311 A US3496311 A US 3496311A US 663076 A US663076 A US 663076A US 3496311D A US3496311D A US 3496311DA US 3496311 A US3496311 A US 3496311A
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Prior art keywords
pushbutton
contacts
slides
plate
pushbutton switch
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Expired - Lifetime
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US663076A
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Walter Holzer
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
    • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
    • H01H13/72—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard wherein the switch has means for limiting the number of operating members that can concurrently be in the actuated position
    • H01H13/74—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard wherein the switch has means for limiting the number of operating members that can concurrently be in the actuated position each contact set returning to its original state only upon actuation of another of the operating members
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H1/00—Contacts
    • H01H1/12—Contacts characterised by the manner in which co-operating contacts engage
    • H01H1/14—Contacts characterised by the manner in which co-operating contacts engage by abutting
    • H01H1/20—Bridging contacts

Definitions

  • the invention relates to pushbutton switches of the kind having a housing for the mechanical operation of the pushbuttons and one or more carriers for electrical contacts.
  • An object of the invention is to eliminate these drawbacks and to provide a pushbutton switch of the kind described, which is of simple design, less expensive and occupies less space than known pushbutton switches.
  • a pushbutton switch of the kind having a housing for the mechanical operation of the pushbuttons and one or more carriers for electrical contacts, wherein the housing cornprises two plates of insulating material, which serve to control the pushbutton slides and to carry the electrical contacts.
  • the carrier for the electrical contacts consists of at least one baseplate containing slots into which the contacts can be inserted.
  • this facilitates assembly, since the insertion of the contacts is extremely easy and can be carried out quickly.
  • Two such contact plates should preferably be provided, through which the contacts are inserted.
  • pushbutton slides can be fitted with tags and springs, resulting in springy contacts that are easy to fit and remove.
  • one of the two baseplates may well serve as a stop for the pushbutton slide. This makes it unnecessary to fit a separate stop, so that in this respect, too, the pushbutton switch is simpler, and fewer possible components are used which simplifies their assembly.
  • Another feature of the invention provides for the catch slides to be carried in slots in the housing frame.
  • a particularly advantageous feature of the invention is that both the plates of insulating material already mentioned are gripped in a frame forming three sides of 3,496,311 Patented Feb. 17, 1970 the housing, the fixing plate being flanged on to this frame. Because the frame is U-shaped, the other fixing plate does not require any shaping, which naturally represents further simplification in manufacture.
  • the front fixing plate may be riveted or welded to the other, curved, plate. With a frame of flanged design, it is also possible to use screws for assembly.
  • FIGURE 1 is a plan of pushbutton switch according to the invention, with the top plate removed;
  • FIGURE 2 is a vertical section taken along the line A-B in FIGURE l, with a top plate;
  • FIGURE 3 is an underneath plan view of the pushbutton switch illustrated in FIGURES 1 and 2;
  • FIGURE 4 is a similar view to FIGURE 3, but with a baseplate fitted;
  • FIGURE 5 is a front view of the pushbutton switch.
  • FIGURES l and 2 show two plates of insulating material, 1 and 2, which serve to carry a number of pushbutton slides 5.
  • the pushbutton slides 5 are fitted to slide at their front ends in the plate 1 and at their rear ends in the plate 2.
  • the plate 2 is bent to form a U and is provided with a flange to which the plate 1 is riveted.
  • the contacts are merely represented diagrammatically in position; in fact, as will be described hereinafter, they are inserted (see FIGURE 2) in slots in the baseplate 6.
  • FIGURE 2 also shows a top plate 11, having slots through which the contacts 8 are likewise inserted.
  • each pushbutton slide 5 is fitted with tags 9 and springs 10.
  • the baseplate 6 is formed with a front extension which extends beyond the plate of insulating material 1, to act as a stop for the pushbutton slide 5 provided with a nose-like projection, 14, which engages the extension when the pushbutton slide 5 is pushed in.
  • a return spring, 12, is fitted in the pushbutton slide 5, which restores the pushbutton slide 5 to its inoperative position as illustrated in FIGURE 2.
  • FIGURE 3 shows, two catch slides 3 and 4 which are mounted in the plate of insulating material 2.
  • Two of the pushbutton slides 5 mounted on the catch slide 3 have a stop to ensure that operation is not possible until two other pushbutton slides 5 have been pressed.
  • the other catch slide 4 has no cam projection at one button, to ensure that when this button is pressed the adjacent one does not spring out. The travel is the same for all the buttons. Contacts may lbe provided as desired, i.e. break, make, or change-over contacts.
  • the depth of the pushbutton slide according to the invention is equivalent to the width of the two catch slides 3 and 4. The height is determined by the width required to accommodate the button slides and catch slides combined, because these work in parallel planes and not, as in known pushbutton slides, at right angles to each other, which saves a considerable amount of space.
  • the contacts 8 are all made up as units and can be plugged in, as already stated. Thus, all that is needed is a single movement to set up the contact studs in different positions.
  • the contacts 8 can be stamped out very economically.
  • the pushbutton slides 5 themselves are made in one piece, preferably by press or injection moulding.
  • the pushbutton switch When the pushbutton switch is used for washing machines, it is sufficient, apart from the Off-button, i.e. the larger button 5 (see FIGURE 3), to provide four selector buttons suitable for all programmes.
  • the Off button should preferably be coloured red, and when operated it releases all the buttons and remains in the Off position, in which the head of the button is aligned with al1 the other buttons. The mode of operation of the rest of the buttons will be apparent from FIGURE 3.
  • FIGURE 4 sho-ws, in particular, the baseplate 6 containing slots 7 for the contacts 8, while FIGURE 5 serves, more particularly, to show the dimensions of the front plate 1 of insulating material, and the holes 15 for riveting the plate '1 to the plate of insulating material 2 as hereinbefore, described.
  • FIGURE 3 also makes clear how the pushbuttons S areguided by the front plate 1.
  • the plates 6 and 11 are held directly by the plates of insulating material 1 and 2, resulting in the simplification of the switch construction already mentioned.
  • the manufacture and assembly of the switch is particularly simple, in that the contacts 8 are inserted into the parallel slots 7 in the baseplate 6 and the pushbutton slides 5, fitted with their tags 9 and springs 10, are placed in position. 'Ihen the top plate 11 is fitted in position over the contacts 8, likewise by their corresponding slots, and ythe shoulders of the contacts 8 are bent over or set at an angle to secure the plates 6 and 11 to each other. This bending or setting of the contacts 8 is necessary only in respect of two or three contacts 8 located in the middle of the plates.
  • a U-shaped member which is also known as the chassis is then pushed into position and the front plate 1 is riveted or welded to it.
  • the compression springs 12 are then inserted into the recesses provided for them.
  • a safety plate 16 (see FIGURE 2) is provided. Finally, the catchslides l 3 and 4 are inserted; these can .readily be replaced subsequently by others.
  • the stop by which the travel of the Ipushbutton slides 5 is limited, is located in the recess for the return springs 12, and also prevents the pushbuttons 5 from jumping out of the front plate 1.
  • a pushbutton switch comprising a substantially U- shaped lirst member of insulating material, said member comprising a bottom portion, integral side portions and ilange portions extending outwardly from the ends of said side portions, a second member of insulating material secured to said first memberand closing oif the top thereity of contacts carried by said third and fourth members, 4
  • said pushbuttons slides carrying spring biased tags, means whereby said tags engage said contacts, and at least one catch slide being operatively engaged with at least some of said pushbutton slides and being carried and slidingly engaged by said rst member.

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  • Push-Button Switches (AREA)
  • Slide Switches (AREA)

Description

` Per.l 17,1910 l Filed Aug. 24, 19s? PusHBuTT'oN swn'ca 2 Sheets-Shut 1 AFE.
l N V E NTO R i WA LTER HOLZER By ttorne'y n Filed Aug. 24,1961
v v 'PusHBUTToN SWITCH4 2 Sheets-Sheet 2 l I il mi I Figli.
' INVENTORz WALTER HoLzEQ 77/94? AHOrn ys y' 4w. HoLzER 3,496,311`
United States Patent O H Int. el. Hoih 9/26 U-S. Cl. 200- 5 Claims ABSTRACT 0F THE DISCLOSURE Pushbutton switch which has a single housing both for the mechanical operation of the pushbuttons and also for carrying the electrical contacts and slides.
The invention relates to pushbutton switches of the kind having a housing for the mechanical operation of the pushbuttons and one or more carriers for electrical contacts.
Existing pushbutton switches of this kind have two separate housings, one for mechanical operation, that is to say for the control of pushbutton slides, for mechanical locking and so forth, and the other as an added contact housing to carry the electrical contacts. This makes them rather expensive and bulky, large numbers of components, particularly stamped-out parts, having to be used. In some cases, too, the pushbutton slides and catch slides are assembled in two parts, so that assembly is also complicated, especially as, in this known kind of pushbutton switch, the button-slide levers are at right angles to the plane of the catch slides.
An object of the invention is to eliminate these drawbacks and to provide a pushbutton switch of the kind described, which is of simple design, less expensive and occupies less space than known pushbutton switches.
According to the present invention there is provided a pushbutton switch of the kind having a housing for the mechanical operation of the pushbuttons and one or more carriers for electrical contacts, wherein the housing cornprises two plates of insulating material, which serve to control the pushbutton slides and to carry the electrical contacts.
In this way, only a single housing is required, to meet both the mechanical and the electrical requirements of the pushbutton switch. The pushbutton switch conforming to the invention thus makes it possible to dispense with many of the parts used hitherto,
Another feature of the invention is that the carrier for the electrical contacts consists of at least one baseplate containing slots into which the contacts can be inserted. Among other advantages, this facilitates assembly, since the insertion of the contacts is extremely easy and can be carried out quickly. Two such contact plates should preferably be provided, through which the contacts are inserted.
In that case, according to a further advantageous feature of the invention, pushbutton slides can be fitted with tags and springs, resulting in springy contacts that are easy to fit and remove. Moreover, one of the two baseplates may well serve as a stop for the pushbutton slide. This makes it unnecessary to fit a separate stop, so that in this respect, too, the pushbutton switch is simpler, and fewer possible components are used which simplifies their assembly.
Another feature of the invention provides for the catch slides to be carried in slots in the housing frame.
A particularly advantageous feature of the invention is that both the plates of insulating material already mentioned are gripped in a frame forming three sides of 3,496,311 Patented Feb. 17, 1970 the housing, the fixing plate being flanged on to this frame. Because the frame is U-shaped, the other fixing plate does not require any shaping, which naturally represents further simplification in manufacture. The front fixing plate may be riveted or welded to the other, curved, plate. With a frame of flanged design, it is also possible to use screws for assembly.
The invention will be further described by way of example with reference to the accompanying diagrammatic drawings, in which:
FIGURE 1 is a plan of pushbutton switch according to the invention, with the top plate removed;
FIGURE 2 is a vertical section taken along the line A-B in FIGURE l, with a top plate;
FIGURE 3 is an underneath plan view of the pushbutton switch illustrated in FIGURES 1 and 2;
FIGURE 4 is a similar view to FIGURE 3, but with a baseplate fitted; and
FIGURE 5 is a front view of the pushbutton switch.
Referring to the drawings in detail FIGURES l and 2 show two plates of insulating material, 1 and 2, which serve to carry a number of pushbutton slides 5. As can be seen, the pushbutton slides 5 are fitted to slide at their front ends in the plate 1 and at their rear ends in the plate 2. The plate 2 is bent to form a U and is provided with a flange to which the plate 1 is riveted. The contacts are merely represented diagrammatically in position; in fact, as will be described hereinafter, they are inserted (see FIGURE 2) in slots in the baseplate 6.
FIGURE 2 also shows a top plate 11, having slots through which the contacts 8 are likewise inserted. AS can be seen from FIGURES l and 2, each pushbutton slide 5 is fitted with tags 9 and springs 10. The baseplate 6 is formed with a front extension which extends beyond the plate of insulating material 1, to act as a stop for the pushbutton slide 5 provided with a nose-like projection, 14, which engages the extension when the pushbutton slide 5 is pushed in.
A return spring, 12, is fitted in the pushbutton slide 5, which restores the pushbutton slide 5 to its inoperative position as illustrated in FIGURE 2.
FIGURE 3 shows, two catch slides 3 and 4 which are mounted in the plate of insulating material 2. Two of the pushbutton slides 5 mounted on the catch slide 3 have a stop to ensure that operation is not possible until two other pushbutton slides 5 have been pressed. The other catch slide 4, has no cam projection at one button, to ensure that when this button is pressed the adjacent one does not spring out. The travel is the same for all the buttons. Contacts may lbe provided as desired, i.e. break, make, or change-over contacts. The depth of the pushbutton slide according to the invention is equivalent to the width of the two catch slides 3 and 4. The height is determined by the width required to accommodate the button slides and catch slides combined, because these work in parallel planes and not, as in known pushbutton slides, at right angles to each other, which saves a considerable amount of space.
The contacts 8 are all made up as units and can be plugged in, as already stated. Thus, all that is needed is a single movement to set up the contact studs in different positions. The contacts 8 can be stamped out very economically. The pushbutton slides 5 themselves are made in one piece, preferably by press or injection moulding.
When the pushbutton switch is used for washing machines, it is sufficient, apart from the Off-button, i.e. the larger button 5 (see FIGURE 3), to provide four selector buttons suitable for all programmes. The Off button should preferably be coloured red, and when operated it releases all the buttons and remains in the Off position, in which the head of the button is aligned with al1 the other buttons. The mode of operation of the rest of the buttons will be apparent from FIGURE 3.
FIGURE 4 sho-ws, in particular, the baseplate 6 containing slots 7 for the contacts 8, while FIGURE 5 serves, more particularly, to show the dimensions of the front plate 1 of insulating material, and the holes 15 for riveting the plate '1 to the plate of insulating material 2 as hereinbefore, described. FIGURE 3 also makes clear how the pushbuttons S areguided by the front plate 1. In addition, the plates 6 and 11 (see also FIGURE 2) are held directly by the plates of insulating material 1 and 2, resulting in the simplification of the switch construction already mentioned.
The manufacture and assembly of the switch is particularly simple, in that the contacts 8 are inserted into the parallel slots 7 in the baseplate 6 and the pushbutton slides 5, fitted with their tags 9 and springs 10, are placed in position. 'Ihen the top plate 11 is fitted in position over the contacts 8, likewise by their corresponding slots, and ythe shoulders of the contacts 8 are bent over or set at an angle to secure the plates 6 and 11 to each other. This bending or setting of the contacts 8 is necessary only in respect of two or three contacts 8 located in the middle of the plates. A U-shaped member which is also known as the chassis is then pushed into position and the front plate 1 is riveted or welded to it. The compression springs 12 are then inserted into the recesses provided for them. To prevent these springs from dropping out, a safety plate 16 (see FIGURE 2) is provided. Finally, the catchslides l 3 and 4 are inserted; these can .readily be replaced subsequently by others. The stop by which the travel of the Ipushbutton slides 5 is limited, is located in the recess for the return springs 12, and also prevents the pushbuttons 5 from jumping out of the front plate 1.
What I claim is:
1. A pushbutton switch comprising a substantially U- shaped lirst member of insulating material, said member comprising a bottom portion, integral side portions and ilange portions extending outwardly from the ends of said side portions, a second member of insulating material secured to said first memberand closing oif the top thereity of contacts carried by said third and fourth members, 4
said pushbuttons slides carrying spring biased tags, means whereby said tags engage said contacts, and at least one catch slide being operatively engaged with at least some of said pushbutton slides and being carried and slidingly engaged by said rst member.
2. The pushbutton switch of claim 1 wherein said at least one catch slide extends transversely to said pushbutton slides and `being slidably carried `by said side portions of said first member.
3. The pushbutton switch of claim 1 wherein said lirst and second mem-bers are secured together by riveting.
4. The pushbutton slide of claim 1 wherein said first and second members are secured together by welding.
5. The pushbutton switch of claim 1 wherein said third and fourth members are provided with aligned slots through which said contacts extend and wherein at least some of said contacts are bent beyond the outer faces of said members in order to secure said members together.
References Cited UNITED STATES PATENTS 2,691,702 10/1954 Auisoo. 2,831,075 4/1958 bomko ot o1. 3,210,484 10/1965 Dorsey. 3,346,706 10/1967 Woodward.
FOREIGN PATENTS 870,028 6/1961 GrootBritoioj ROBERT K. SCHAEFER, Primary Examiner M. GINSBURG, Assistant Examiner U.S. Cl. X.R. 68-12
US663076A 1966-08-26 1967-08-24 Pushbutton switch Expired - Lifetime US3496311A (en)

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Application Number Priority Date Filing Date Title
DEH0060340 1966-08-26

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US663076A Expired - Lifetime US3496311A (en) 1966-08-26 1967-08-24 Pushbutton switch

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DE (1) DE1640333B1 (en)
ES (1) ES344743A1 (en)
FR (1) FR1538814A (en)
GB (1) GB1201658A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3886335A (en) * 1973-01-26 1975-05-27 Ind Electronics Engineers Inc Collated cable matrix switch

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691702A (en) * 1949-03-17 1954-10-12 Grigsby Allison Company Inc Push-button electric switch
US2831075A (en) * 1956-02-13 1958-04-15 Switchcraft Push button switches
GB870028A (en) * 1958-08-20 1961-06-07 Schoeller & Co Improvements in or relating to multiple push-button electrical switches
US3210484A (en) * 1962-04-20 1965-10-05 Automatic Elect Lab Push button device
US3346706A (en) * 1966-07-14 1967-10-10 Gen Electric Pushbutton switch with improved slider means for optional circuit selection

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1584010A (en) * 1923-11-12 1926-05-11 Mitchell Co R Electrical switch
FR956054A (en) * 1946-03-20 1950-01-24
DE1765823U (en) * 1958-03-07 1958-04-30 Eugen Sasse K G Dr BUTTON SWITCH UNIT WITH FUSE AGAINST THE SIMULTANEOUS ACTIVATION OF TWO OR MORE BUTTON SWITCHES.
DE1766172U (en) * 1958-03-13 1958-05-08 Robert Seuffer K G KEY ARRANGEMENT.
DE1767092U (en) * 1958-03-20 1958-05-22 Schoeller & Co Elektrotech ROW KEY SWITCHES WITH PRINTED WIRING.
DE1776463U (en) * 1958-08-20 1958-10-30 Schoeller & Co Elektrotech MULTIPLE PUSH SWITCH WITH TWO CONTACT PLATES.
DE1796765U (en) * 1958-11-29 1959-10-01 Preh Elektro Feinmechanik KEY SWITCHES WITH SLIDING KEYS.
DE1806166U (en) * 1959-05-16 1960-02-18 Preh Elektro Feinmechanik KEY SWITCHES WITH A LOCKING LINK IN THE SHAPE OF A SO-CALLED FORWARD LEVER.
DE1826259U (en) * 1960-05-02 1961-02-09 Philips Nv SLIDING SWITCH ON AN INSULATING PLATE, IN PARTICULAR FOR RADIO RECEIVERS WITH PRINTED WIRING.
DE1839996U (en) * 1961-01-10 1961-10-26 Preh Elektro Feinmechanik KEY SWITCHES WITH MUTUAL RELEASE KEYS.
DE1223441B (en) * 1963-06-19 1966-08-25 Philips Nv Key arrangement for recording and / or playback devices
DE1719414B2 (en) * 1964-11-17 1973-05-10 PREVENT THE SEDIMENTATION OF PIGMENT SUSPENSIONS
DE1807974A1 (en) * 1968-11-09 1970-07-30 Falke Rohen Fa Franz Fine-mesh panty hose

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2691702A (en) * 1949-03-17 1954-10-12 Grigsby Allison Company Inc Push-button electric switch
US2831075A (en) * 1956-02-13 1958-04-15 Switchcraft Push button switches
GB870028A (en) * 1958-08-20 1961-06-07 Schoeller & Co Improvements in or relating to multiple push-button electrical switches
US3210484A (en) * 1962-04-20 1965-10-05 Automatic Elect Lab Push button device
US3346706A (en) * 1966-07-14 1967-10-10 Gen Electric Pushbutton switch with improved slider means for optional circuit selection

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3886335A (en) * 1973-01-26 1975-05-27 Ind Electronics Engineers Inc Collated cable matrix switch

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DE1640333B1 (en) 1971-03-04
FR1538814A (en) 1968-09-06
ES344743A1 (en) 1968-10-16
GB1201658A (en) 1970-08-12

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