US2921999A

US2921999A - Inertia switch

Info

Publication number: US2921999A
Application number: US650046A
Authority: US
Inventors: Jr Robert M Ziegler
Original assignee: Hughes Aircraft Co
Current assignee: Raytheon Co
Priority date: 1957-04-01
Filing date: 1957-04-01
Publication date: 1960-01-19
Anticipated expiration: 1977-01-19

Description

Jan. 19, 1960 R, M, zlEsLER, JR 2,921,999

INERTIA .SWITCH Filed April l, 1957 9% ark,

Wi/Wai. Rober? M Ziegler, Jr.,

y k (99m:

United States Patent INERTIA SWITCH' Robert' Ziegler, Jr.,.Los Angeles, Calif., assignor to Hughes Aircraft Company, Culver City, Calif., a corporation'of Delaware Application April 1*, 19'57, Serial Noa 650,046 6 Claims. (C1. 20o-61.52)

The present invention relates generally -to switch mechanisms and relates more specifically tof switches of theinertia type, physical movement thereof being adapted to' effect interconnection between contact elements.

.Heretofore, inertia type switches have been known' that employ moving elements, at least a portion of which comprises a Weight member. These weight members are usually connected to shafts or arms and movement thereofunder inertia induced forces serves to move the weight and'y shaft or arm. TheV sh'afts or arms used in this type of mechanism have generally been arranged in such amanner as to effect closure of contact members. These prior structures have had numerous disadvantages inasznuch as high friction forces are usually present, thus to createlubrica'tion problems. Additionally, these struc# tur'esl'iaye been heavy, physically of a large size, employed many small complex parts, required considerable wiring operations during assembly and were not well suited for .mass production' manufacturing techniques. In operating characteristics of prior devices, it has been common to employ --at least 50% of the weight mass in order to produce' a' contact force and' when this factor is' coupled with problems relating to contact cleanliness, many failures of the prior structures have resulted. In prior mechanisms that employ springs of various` types, itV is desir/'able' .that suitable preloading of the springs be 'accomplished before use of the switch. Prior devices have' been constructed in such a manner as to prevent adequate and reliable adjustment means for settingspring preloading'. Y

Y It is, accordingly, one object of the invention to provide aniiietiaswitch mechanism having features of novelty and functional characteristics to overcome the beforementioned difficulties and problems associated with prior devices intended for a similar purpose.

l It is another important object of the invention toptovide' inertia switch mechanism that is extremely simple iiiA construction, reliable in operation, eicient in use,

relatively inexpensive and of a nature enabling manufacture thereofl in mass` production situations.

It is a further important object of the invention to provide an inertia switch mechanism wherein a weight ni'e'ibei actsphysically to connect a plurality of contacts whereinl a wipingy action is established between the Weight member and the contacts, thereby to promote eicient electricalV connection between the contacts and the weight member.

Itis still another object of .the invention to provide an inertia switch mechanism wherein many of the components thereof are structurally combined, thus to reduce' the over-all number of components and provide a more simple" and inexpensive structure.

A further important object of the invention is to provide a switch mechanism `adapted for operation upon application'of inertia forces thereto and wherein a spring biasing means applied to a movable weight may be adiusted for preloading thereof, thus to establish more nearly spring rate characteristics.

Other and further important objects of the invention will` become apparent from the disclosures in the' following detailed specification, appended claims and accompanying drawing, wherein:

Figure 1 isa longitudinal sectional view of the switch mechanism of the present invention and showing the components in position prior to inertia induced movement thereof;

Fig. 2 isan isometric View showing one of the composite contact members;

Fig. 3 is an isometric view showing a subcombination of the assembly of the present switch together with another of the composite Contact members; and' Fig. 4 is a longitudinal sectional view similar to Fig. 1, showing a modification of the invention.

Withreference to the drawing, it is fto be noted that the present* inertia switch mechanism comprises a tubular member 10 that may be constructed from any suitable material and is preferably nonconductive. They tubular member 10 has an internal cylindrical bore 11 and a recess 12 wit-h one end thereof. The other end of the member 10 isVA reduced in diameter and threaded as at 13'.

An'- insert 14, of nonconductive material, is disposed in the cylindrical bore 11 and has a flange 15 that is adapted toI overlie an end of the member 10. A contact member 16 is disposed about the insert 14 and between the outer' surface of the insert and the bore 11. The contact member 1:6 has a plurality of tabs 17 bent from one end thereof and? adapted for disposition between the one end of the member 10 and the fiance 15. A threaded sleeve 18 is adapted to engage t-he threads 15, the sleeve having a radially inwardly extending flange 19 that is in turn adapted to engage an outer surface of the flange 1S whereby to secure the insert 14 and the Contact member 16 in position withinthe bore 11. The sleeve 18 is also constructed from a nonconductive material. As shown primarily in Figs. l and 2, the contact member 16 further includes a tubular portion 20 that is constructed from a at sheet of material and rolled into the tubular form, thus defining longitudinally extending, adjacently disposed free edges 21. To enable electrical connection to the metallic contact member 16, an ntegral lug 22 is disposed therefrom and extends through a suitable slot (not shown) in ythe flange 1S. In accordance with the usual practice, the lug 22 is provided with an opening therethrough to facilitate attachment'of a wire lead. The end of the cylinder 20, remote from the tabs 17, integrally supports a plurality of contacts 23 that are supported on angularly inwardly directed end portions 24 formed from integral extension portions Z5. The contacts 23 are in the form of dimples in the material of thel contact member 16 and the outer raised portions thereof may either be coated with a highly conductive material such as silver or the like, or may have a finite layer of silver deposited thereon.

`Another Contact member is indicated generally at 26 and is disposed in an end of the bore 11 remote from the insert 14. With reference to Figs. l and 3, the contact member 26 comprises a threaded shank portion 27 having al disc 28 formed integrally on one end thereof. A cylindrical contact carrying member 30 is disposed in an annular groove in the disc 28 and secured thereto as by soldering, for example.- The member 30 is similar in construction to the previously described cylinder 20, being constructed from a rolled sheet of material and having adjacent longitudinal edges 31. A plurality of integral extension portions 32 are disposed from one edge of the member 30 and have angularly, radially inwardly directed portions 33 integrally disposed therefrom.A The portions 33 are adaptedlto carry dimpled contacts 34. As shown in Figi, a transversely disposed supporting web 35 is positioned within the member 30 and secured thereinby means of soldering or the like. Additionally, the web 35 is provided with a central opening 36, the shank 27v and high rate mass production of these integral components. i

While the contact members hereof are shown as being provided with three equallyfcircumferentially spaced contacts that are carried by the angularly disposed members, it is to be understood thatV any number Vof contacts may be provided commensurate Ywith the ultimate use thereof in particlarsstructures. The 4triangular arrangementl of the contacts and the angular disposition thereof provides a kinematic structure as is desirable in the present instance. k-

An end closure member 38 is threadably disposed in the recess 12 in one endA of the tubular member 10, the

Aclosure member havingareducedfdiameter portion 40 which extends into the bore-11. A sealing ring member 41 isv disposed in a suitable groove in the portion 40 for cooperation between the closuremember 38 andthe bore 11. The'outer end surface of the member 38'is provided with cross cut grooves 42 to enable application of tools for disposing the closure member in the recess12. The closure member 38 has a central threaded bore '43 in which the shank 27 isr threadably disposed, the outer vend of the shank extending beyond the outer surface ofthe member 38 and having a nut 44 carried thereby, a contact terminal l45 being adapted for disposition between the nut 44 and 'the outer surface of the member'38, thereby to'lprovide an electrical connection for the contact member The 'l nut 44 also serves to lockthe shankl 27 with respect to the closure member 38, the shank 27 being provided with flattened areas 46 on the exposed end thereof, whereby to permit application of tools for turningv the shank and the contact member 26.V -f ijf@ With reference again to'Fig. 1a weight in the formof a spherey47 is disposed within the bore 11 and intermediate the

contacts

23 and 34. The sphere 47v maybe made from any Vsuitablepreferably Vdense metallic -rnateria1,

thus to enable both a weight function'and a Contact con necting function. A tension spring 48 has one end 50 disposed through a bore 51 in the sphere 47 and connected to the sphere as by soldering 52. The spring48 Vextends through'a Ycentral areabetween the contact portions 24 and is confined within abore 53 inthe inse'rtv14.l Another end of the springy 48'has Van extension portion 5.4`that is disposed through a centralbore 55V in a threaded stud 56.l Thestud 56 threadably engages the insert 14 and extends outwardly therefrom. "The spring Vportion 54 has a ball V57 secured thereto and disposed outwardly from the outer end of the bore 55; The ball S7 issecured to the stud 56 as by soldering 58, The outer end'of the' stud 56 `is also fitted with a nut 60 that is adapted to secure the stud against rotation relative to the insert 14 and to confine a terminal 61 about the stud. The terminal 61 serves to provide means for establishing electrical connection'with the sphere 47 by way of the stud 5,6 and spring 48;

In initial assembly of the present device, the contact member 16 and insert 14 are secured in position, together with the sphere 47 and associated spring 48. The portion 50 of the spring 48 is extended outwardly through the opening 36 and bore 37 inthe Ycontact member 26 and closure member 38 respectively and provided with a hookk shown by the dotted lines at 62 Vin Fig. 1. The hook 62 serves to provide means by which a predetermined tension may beapplied to the spring 48, whereby to,V establislitheforce j ofY the sphere 47 against the.` contacts 323. p .'Iherefj after the end portion of the spring 48 is cut off adjacent the soldered joint 52 and thecontact member 26, together with the end closure member 38, are again installed in position. The outer end of the bore 37 may thereafter be closed as by any suitable material. y

Under inuence of acceleration in an axial direction of the tubular'member 10, and rightwardly as shown in the drawing, the sphere 47 will be moved leftwardly against the Vtension of the spring 48 and at apredetermined value of acceleration, whereby to breakthe normal contact, be-- tween the sphere and the contacts.23. Ata highervalue of acceleration, the sphere will have completed its leftward movement to the position'shown by the dotted lines in Fig. l, whereby to make contact with the contacts 34. The relative axial positions of the

contacts

23 and 34 are adjusted by use of the shank 27. It is to be notedthat as the sphere 47 makes contact with the

contacts

23 or 34,

f A the angularly'disposed portions24 or 33 respectivelyA will be deformed, whereby to provide a wiping action between the contacts and the` surface ofthe sphere 47.1Y The spring characteristics vof the material ofthe cylinder 2tland the member 30 serves to return the portionst24 and 33 to their Y e original positions following disengagement thereof by the sphere 47. The sphere 47 is maintained in axial alignment with the

contacts

23 and 34 by close confinement thereof within the bore 11. Due to this particular construction, movement of the sphere 47 may be accomplished only upon axial movement of thetubularmember 10 and asso;

ciated structure, lateral 'movement of thesefstructures having no effect upon the contacts. z,

In connection with the specifcffunctional characteristics of the presen-t switch arrangement, it should be pointed'out that Vthe contact closing'value 'ofacceleration is a function. of the rate of the spring 48,' the mass of Y' the sphere 47 and the spacing betweenvthe sphere and the contacts. Additionally, the acceleration sensitivity of such a structure is a function of the Vmass of the sphere and the springv rate.- In many installationalv situations, the desired spring ratesfor a particular range of acceleration vmay easily be obtained through use lofiberyllium copper springs, thereby to minimize the series resistance to the moving contactas defined by the sphere 47. ,The

contact portions

24 and 33 are preferably flexible enough todeilect slightly uponcontact bythe sphere, thus to provide the before-mentioned wiping action. The use of the present axially movablecontacts not only permits a lower contact resistance but also insures greater reliability for the structure. 'Additionally, accurately dimensioned spheres are readily obtainable and are relativelyinexpensive and compact, as compared to pivoted weight arrangef ments. The particular kinematic arrangement of the Y contacts Vand the specificV structuralcharacteristicsthere-y l of vserve to Aeliminate any tendency of the sphere tobounce 's lrelative to the contacts andV no damping of the'action is required ,The relatively large available adjustment of the axial relative positions of the contacts 23 andV 34 serves to compensate'fortolerance differences in the `dej f vicer'andV for'varying spring rates.

Furthermore, since the connections` are relatively widely spacedinsula tion resistancek ashbetween ythese contacts is Vrelativelylhigh and Ithe possibility of voltage breakdownis extremely low;

In Fig. 4v a modiiicationi of the invention is shown `wherein like parts are indicated-by single primed referf ence characters. In this form ofthe invention, the insert 14' has a spring element 63 disposedrwithinV the recess 53 and secured thereinuby means of aV press lit. A plurality of spring members 64 are disposed from oneend of the spring element 63; Additionally, aportion 50 of the spring 48 has a sleeve 65v secured thereto, one end of the sleeve Vbeing disposed in a suitable recess 66 in the sphere 47.A `Theother end of the sleeve 65 isY provided with an annular enlargement 67 that normally is con-IY tained within the confines of the spring members 64;l I 'jInthis modilied formof the invention, 'it-may' thus'fbe seen that as inertia forces a'reappli'edto theasphere 4'1,

agence@ the force' of the sprin-'ggmember 6'4 must' be overcome before the sphere may "move in' a leftward direction: When the force of, the spring members 64 is overcome, the enlargement 67 will be' pulledi therethrough, thus providin'g a snap action for engagement of the sphere 47 with the contacts 34 and for separation ofthe sphere from the contacts 23. The spring member 64 servesalso to retain the sphere 47 in contact with the contacts 34 until a reduction in inertia forces reaches a-level to permit the spring 48 to againdgraw the enlargement 67 through the spring member 64. Aconstruction of this type insures positive action of the device when'engaging the contacts and less time between release of one setof contacts and engagement With'another.

vHaving thus described the invention and thepresent embodiments thereof, it is desiredto emphasize the fact that many further modifications may be resorted to in a manner limited only by a just interpretation. of the following claims.

I claim:

l. An inertia electrical switch apparatus comprising, in combination:V an elongated tubular housing; closure members threadably engaging each longitudinal end of said housing; a pair of contact Ncarrying structures; one of said structures comprising a tubular portion havingmeans for retaining said portion in association with one of said closure members and in one end of said housing, the other of said structures comprising a tubular portion; means for longitudinally adjustably connecting said other of said structures to ano-ther of said closure members; a plurality of contacts carried by each of said structures and disposed in opposed spaced relationship within said housing; a spherical weigh-t disposed in said housing intermediate said contacts; tension spring means connected with said weight and said one of said closure members for biasing said weight into normal contact with contacts carried by one of said structures, inertia forces being adapted longitudinally to move said weight into contact with contacts carried by said other of said structures; and means for providing independent electrical connection with said contact structures and said weight, said connection with said weight including said tension spring means.

2. An inertia electrical switch apparatus comprising, in combination: an elongated tubular housing; closure members threadably engaging each longitudinal end of said housing; a pair of contact carrying structures, one of said structures comprising a tubular portion having means for retaining said portion in association with one of said closure members and in one end of said housing, the other of said structures comprising a tubular portion; means for longitudinally adjustably connecting said other of said structures to another of said closure members; a plurality of contacts carried by each of said structures and disposed in opposed spaced relationship within said housing, said contacts being disposed at an acute angle relative to an axis of said housing and in spaced circumferential relationships to each other on each of said structures; a spherical weight disposed in said housing intermediate said contacts; tension spring means connected with said weight and said one of said closure members for biasing said weight into normal contact with contacts carried by one of said structures, inertia forces being adapted longitudinally to move said weight into contact with contacts carried by said other of said structures; and means for providing independent electrical connection with said contact structures and said weight, said connection with said weight including said tension spring means.

3. An inertia electrical switch apparatus comprising, in combination: any elongated tubular housing; closure members threadably engaging each longitudinal end of said housing; a pair of contact carrying structures, one of said structures comprising a tubular portion having means for retaining said portion in association with one of said closure members and.- inone end.V of said housing, Vvthe other of saidv structures comprising a tubular portion;l

means for longitudinally adjustably connecting said other of said structures to another ofr said closure'members; a plurality of resilient contacts'carried by each of said structures and disposedy in opposed spaced relationship within said housing; afspheric'al weight disposed and laterally closelyV confined in said housing intermediate said contacts; tension spring means connected with said weight and adjustably connected said one of said closure members for biasing saidfweight into normal contactwith contacts carried' by one. of said structures, inertia forces being adapted longitudinally to move said weightv into contact with contacts carried by said other of said structures, said spherical weight contacting said contacts with a wiping action; andv` means for providing independent electrical connection Withsaid contact structures and. said weight, said connection with said weight including said tension spring'vmeans.

4. An inertia electrical switch' apparatus comprising, in combination: an' elongated'ftubular housing; closure members threadably engagingv each longitudinal end of said housing; a'pair of contact carrying structures, one of said structures comprising a tubular portion having means for retaining said portion in association' with one of said closureV members and in one end of said housing, the other of said structures comprising a tubular portion; means for longitudinally adjustably connecting said other of said structures to another of said closure members; a plurality of resilient contacts carried by each of said structures and disposed in opposed spaced relationship within said housing, said contacts being disposed at an acute angle relative to an axis of said housing and kinematically arranged in spaced circumferential relationships to each other on each of said structures; a spherical weight disposed and laterally closely confined in said housing intermediate said contacts; tension spring means connected with said weight and adjustably connected to said one of said closure members for biasing said weight into normal contact with contacts carried by one of said structures, inertia forces being adapted longitudinally to move said weight into contact with contacts carried by said other of said structures, said spherical weight contacting said contacts with a wiping action; and means for providing independent electrical connection with said contact structures and said weight, said connection with said weight including said tension spring means.

5. An inertia electrical switch apparatus comprising, in combination: an elongated tubular housing; an insert in one end of said housing; a closure member threadably engaging the other end of said housing; a pair of contact carrying structures, one of said structures having a tubular portion disposed about said insert and tab means disposed over an end of said housing; a threaded retainer carried by said one end of said housing for securing said insert and said one of said structures in position; shank means for longitudinally adjustably connecting the other of said structures to said closure member; a plurality of resilient contacts carried by each of said contact'carrying structures and disposed within said housing in opposed spaced relationships, said contacts being arranged in groups of three, disposed at equal acute angles relative to an axis of said housing and kinematically arranged in spaced circumferential relationships in each group thereof; a spherical weight disposed and laterally closely confined in said housing intermediate said contacts; a tension spring disposed in a recess in said insert having one end secured to said weight and the other end adjustably connected with said insert whereby to bias said weight into normal contact with one of said groups of contacts as carried by said one of said structures, inertia forces being adapted longitudinally to move said weight into contact with the group of contacts carried by said other of said structures, said spherical weight deecting said contacts upon engagement therewith to provide a wiping action therebetween; and means proyiding independent electrical con- :r'iectionl with said contact carrying structuresV and Vsaid weight', said electricalconnection with said weight including said tension Spring. Y Y f "6. An inertia electrical switch apparatus comprising, in combination: an elongated tubular housing; Van insert in one end ofrsaid housing; a closure member threadably engaging theother end'of said housing; a pair of contact carrying structures, one of said structures having a tubular portion disposed about said insert and tab means disposed over an end of said housing; a threaded retainer carried by said one end of said housing for securing said t insert and said one of said structures in position; shank means for longitudinally radjustably connecting the other of said structures to said closure member; a plurality of r resilient contacts carried by each of'said contact carrying structures and disposed withinV said housing in opposed spaced relationships, said contacts being arranged in groups of three, disposed at equal'acute angles relative to an 'axis of said housing and kinematically arranged in spaced circumferential relationships in each group thereof; a spherical weight disposed and laterally closely conned in said housing intermediate said contacts; a tension spring disposed in a recess in usaid insert having one end secured toY said weight and the other end adjustably i connected with said insert whereby to bias said weight into normal contact with one of said groups of contacts as carried by said one`f saidstructures, vinertia forces being adapted longitudinallyfto moveV said `weight into contact withrthefrgroup' of contacts carried by said other ofsaid structures, said spherical weightV deecting said contacts upon engagement therewith to provide a wiping action therebetween; leaf spring means disposed in said insert recess; an enlargement carried by and disposed froml said weight, said enlargement being adapted for cooperationV with -said leaf spring means to release said weight with a snap action upon inertia induced or spring biased movement thereof; and means providing Vindependent electrical connectionkwith said ycontact carrying structures and said weight, said electrical'connection with said weight including said tension spring.

References Cited in the iile of this patent A' UNITED STATES PATENTS Busacker et al vNovv. 18, 1947 Waldow May 2(7),71958