US 3749864 A
A fluid condition responsive switch comprises an elongated tubular member supporting a sleeve for limited sliding travel therealong in response to angular movement of a cam assembly pivotally supported on the member. During a portion of sleeve travel, a magnetically responsive reed switch, contained within the member, is within the effective magnetic scope of a magnet carried by the sleeve. The cam assembly includes a cam and may also include either a paddle responsive to fluid flow through an associated conduit or a float responsive to predetermined levels of fluid in an associated container.
Claims available in
Description (OCR text may contain errors)
" United States Patent 1191 FOREIGN PATENTS 0R APPILI'CATIVONS 1,287,186
[5 "FLUID CONDITION RESPONSIVE SWITCH A UNIT i v 1 ,;;[;7V5]M Inventor?j Charles 'lfice ll t ille C nn I T ,Asignz .3
22] Filed: Feb'. 28, 1972 21 AppL No; 229,792
52' u;s.c1 200/s1.9M,200/s4c 51 int. Cl. 11011135/40  Field of Search 200/84 B, 84 c, 81.9 M; 5 335/205, 206, 207
[56 References Cited UNITED STATES PATENTS 3,569,648 3 1971 Meyer 6. ZOO/81.9 2,927,176 3/1960 Auld, Jr. 6:61.... zoo/84c 3,632,923. 1/1972 1 Paine 335/205 3,421,124 1 1969 1 Kidd 335 2 5 1/1969 Germany; ..335/205 7  July 31, 1973 933,555 9/1955 Germany m; 290l8l.9 OTHER PUBLICATIONS 1 Williams, 0. T.,: Air Flourswitchfi? IBM,,Tech. Discl.
' "Bun; Vol; 13, Nob/November 1970, 1680 168 1 Primary Examiner- David Smith, Jr.
Attorney'Frederick J. Haesche 571 Q ABSTRACT A fluid condition responsive switch comprises an elongated tubular member supporting a sleeve for limited sliding travel therealong in'r'esponse to angular movement of a cam assembly pivotally supported on'the' 11 Claims, Drawing Figures PAIENIEDJUUI I 3.749.864
FLUID CONDITION RESPONSIVE SWITCH UNIT BACKGROUND OF THE INVENTION This invention relates in general to fluid condition responsive electrical switches and deals more particularly with improved fluid responsive switch units adapted to respond to a fluid flow condition or to a predetermined condition of fluid level in a container or the like.
SUMMARY OF THE INVENTION In accordance with the presentinvention, a fluid con- .dition responsive'switch unit is" providedhwhich com-" BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevational view of a fluid condition responsive switch unit embodying the present invention shown connected to a portion of a fluid conduit, the conduit being shown in longitudinal section.
FIG. 2 is a sectional viewtaken along the line 22 of FIG. 1.
FIG. 3 is a plan view 'of the switch unit of FIG. 1. FIG. 4 is a-fragmentary side elevational view of another fluid condition responsive switch unit embodying the invention shown connected to a portion of a fluid container, the container beingshown in section.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I Turning now to the drawing and 'referring first to FIGS. 1-3. A fluid condition responsive switch unit embodying the invention and indicated generally by the reference numeral 10 is particularly adapted to respond to a fluid flow condition. In FIGS. 1 and 2, the switch unit 10 is shown connected to a fluid source or conduit 12 which may, for example, comprise a standard pipe tee forming part of a fluid conduit and defining a fluid flow path. The illustrated switch 10 is responsive to a predetermined condition of fluid flow in either direction through the tee 12 and generally comprises a mounting structure or housing 14, which has an elongated support member or stem thereon. The stem 16 supports a magnetic actuator indicated generally at 18 for limited travel along a path relative thereto. A magnetically responsive switch element 20 carried by the stem is within the effective magnetic scope of the actuator 18 during a portion of its travel. A fluid responsive cam assembly indicated generally at 22 and pivotally mounted on the support member 16 moves the actuator 18 along its path in response to conditions of fluid flow throughthe tee 12. The actuator 18 is biased into engagement with the cam assembly by a spring 24.
The housing may take various forms, but preferably and as shown, it is formed from two parts and includes a body 26 and a cap 28. The body has a generally cylin- 16 mounted drical inwardly opening bore 30 and a male pipe thread on its inner end for connection with the tee l2 substantially as-shown. An integral hexagonal nut collar surrounds the central portion of the body to facilitate mounting. The cap 28 comprises a conduit connector attached to the outer end of the body 26 and externally threaded at its outer end. The support member 16 comprises an elongated stem which is mounted on the inner end of the cap 28. The stem is generally cylindrical, extends coaxially through the bore 30, and has an axially disposed slot 32 formed in its inner end, as shown in FIG...2. A coaxial bore 34 partially defined by the stem 16 opens outwardly through the capf'28.
The switch element 20 comprises a conventional encapsulated reed switch of magnetically actuated type which includes a plurality of electrical contacts. At least one of the contacts is movable between open and closed positions relative to anotherof the contacts and moves from one to the other of its positions in response to magnetic influence to alter the condition of an associated electrical circuit (not shown). The illustrated reed switch 20 includes a pair of elongated reed contacts which are normally open and which close in response to applied magnetic force, however, it should be understood that other switch forms are contemplated within the scope of the invention. The reed switch 20 is contained within a protective tube 36 slidably received within the'bore 34 and is supported within the stem with its reed contacts extending. longitudinally of the stem. A set screw 38 associated with the cap 28 is provided to releasably secure thejswitch 20 inpreselected position relative to' the stem 16. Electrical lead connections associated with the switch 20 extend from the outer endof the bore 34 forjconnection in an exter' nal electrical circuit (not shown). A grommet'39 seals the outer end of the bore 34. l
Consideringnow the magnetic actuator in further detail, the actuator 18 comprises an axially elongated generally cylindrical sleeve 40 surrounded by ari integral annular collar 42. The sleeve 40 is slidably received on the stem 16 for limited travel th'erealong' and has a generally radially disposed cam surface 44 at its inner end. The actuator 18 also includes a ceramic ring magnet which surrounds the sleeve 40 and rests on the collar 42. The cam assembly 22 includes a cam 48 and a vane or paddle 50 attached to the cam.,The shape of the cam may vary, however, the illustrated cam 48 is a generally circular eccentric cam received in the slot 32 and supported by a pivot pin 52 for pivotal movement about an axis extending transversely of the stem 16.
- The paddle 50 comprises a thin generally rectangular plate attached to the cam and extending radially outwardly therefrom with the faces thereof disposed in a generally axial plane substantially as shown. The spring 24 acts between the housing 14 and the actuator 18 to bias the actuator toward the cam assembly 22 whereby cam 48 engages the cam surface 44.
tuator 18 attains a critical position relative to the reed switch 20 wherein the reed switch is within the effective magnetic scope of the magnet 46, the reed switch contacts close thereby altering the condition of an associated electrical circuit. Further movement of the actuator 18 in an upward direction beyond its critical position does not alter the condition of the switch contacts, which remain in closed position. The actuator 18 attains its critical position when the cam assembly 22 attains an angular position corresponding to a predetermined velocity of fluid flow through the tee 12. Thereafter, any increase in flow velocity through the tee causes further angular movement of the cam assembly without altering the condition of the reed switch 20. Under conditions of increasing flow the paddle 50 may ultimately attain a near parallel position relative to the flow stream through the conduit. In the latter position, the paddle offers little resistance to the flowing fluid which results in minimal pressure drop across the unit at relatively high flow rates. Referring to FIG. 1 and assuming a condition of increasing flow in the direction of the arrow designated by the numeral 53 the cam assembly 22 will pivot in a counterclockwise direction and the paddle 50 may ultimately attain the position indicated by broken lines at 500. Due to the substantially symmetrical arrangement of the paddle S and the cam 48 relative to the axis of the pivot pin 52 ,it will now be apparent that the switch unit will respond in a substantially identical manner to fluid flowing in the opposite direction through the tee 12. As the velocity of flow through the tee 12 decreases, the spring 24 urges the actuator 18 in a downward direction causing the cam assembly 22 to pivot in a clockwise direction. When the actuator 18 reaches its critical position the magnet 46 no longer effectively influences the reed switch whereupon the switch 20 returns to open circuit condition. Under a condition of decreasing flow, the paddle 50 ultimately returns to its original position, as indicated in full lines in FIG. 1.
The switch unit 10 may be adjusted to respond to various fluid conditions by adjusting the position of the switch element 20 relative to the stem 16. As previously noted, the set screw 38 releasably retains the switch element in preselected position relative to the stem. Further variations in the responsive characteristics of the unit may be attained by varying the physical characteristics of the cam assembly or the spring 24.
Referring now to FIG. 3, another fluid condition responsive switch unit embodying the invention and indicated generally at 10a is shown mounted on a container 54 which holds a quantity of fluid 56. The switch unit 100 is particularly adapted to respond to change in the level of the fluid 56 in the container 54 and is identical in many respects to the switch 10 previously described. Parts of the switch unit 10a identical to parts of the switch unit 10 bear the same reference numerals as the previously described switch unit 10 and a letter a suffix and will not be hereinafter further discussed.
Specifically, the switch unit 10a differs from the previously described switch unit in the construction and the arrangement of its cam assembly which is designated generally at 220. More specifically, the cam assembly 22a includes a cam 58 and a float 60 attached to the cam by a rod 62 and adapted to float in the fluid 56. The cam assembly 22a is supported at the inner end of the stem 16a by a pivot pin 52a for moving an actuator 18a in the manner previously described. The cam erally axially disposed slot opening through the inner'-' 1. A fluid condition responsive switch comprising an axially elongated hollow support member haivng a genend thereof, means for mountingsaid support member at its outer end and in fixed position relative to a fluid container, an axially elongated tubular magnet carrier coaxially slidably received on said support member ex ternally thereof for limited travel therealong in one and an opposite axial direction, said magnet carrier having a radially disposed annular cam surface at the inner end thereof, a magnet mounted on said magnet carrier for movement therewith, a magnetically responsive reed switch contained within said hollow support member and having a plurality of electrical contacts adapted for connection in an electrical circuit externally of said support member, at least one of said contacts comprising an elongated reed extending in a generally longitudinal direction and movable between open and closed positions relative to another of said contacts, said one contact being within the effective magnetic scope of said magnet during a portion of said travel and movable from one to the other of said positions in response to the magnetic influence of said magnet to alter the condition of the circuit, a cam partially disposed within said slot and mounted on said support member for piv otal movement in one and an opposite direction about an axis generally normal to said support member axis,
means for biasing said magnet carrier toward said cam to maintain said cam surface in engagement with said cam, and fluid condition responsive means carried by said cam for pivoting said cam in said one direction to move said magnet carrier in response to one condition of the fluid in the container and for pivoting said cam in said opposite direction to move said magnet carrier in response to another condition of the fluid in the container.
2. A fluid condition responsive switch as set forth in claim 1 wherein said cam axis intersects said support member axis and said cam is generally symmetrical about an axial plane which extends through said cam axis.
3. A fluid condition responsive switch as set forth in claim 2 wherein said cam is further characterized as an eccentrically mounted circular cam.
4. A fluid condition responsive switch as set forth in claim 1 wherein said reed switch is axially movable relative to said support member and said fluid condition responsive switch includes means for releasably retaining said reed switch in preselected axial position relative to said support member.
5. A fluid condition responsive switch as set forth in claim 1 wherein saidfluid condition responsive means conprises a float connected to said cam and responsive to the level of fluid in the container.
6. A fluid condition responsive switch as set forth in claim 1 wherein the container comprises a fluid conduit defining a fluid flow path and said fluid condition responsive means comprises a vane connected to said cam and disposed within said conduits, said vane having a surface thereof disposed generally transversely of the fluid flow path.
7. A fluid condition responsive switch comprising a housing for mounting said switch in a fixed position relativeto a fluid container and havingva generally cylindrical axially inwardly opening bore, an axially elongated stem mounted at one end in said housing and extending coaxially inwardly through said housing bore, said stem having a generally cylindrical coaxial blind bore opening through the outer end of said housing and an axially disposed slot opening through its inner end, a pivot pin mounted in said stem inner end and extending transversely of said slot, a cam partially disposed in said slot and journalled on said pin for pivotal movement in one and an opposite direction relative to said stem and about an axis extending transversely of the axis of said stern, an axially elongated generally cylindrical tubular sleeve slidably received on said stem for limited sliding movement in one and an opposite axial direction therealong, said sleeve having a generally radially disposed annular cam surface at its inner end, a spring surrounding a portion of said stem and biasing said sleeve toward said cam to maintain said cam surface in engagement with said cam, an annular magnet surrounding a portion of said sleeve and mounted thereon for movement therewith a magnetically responsive encapsulated reed switch contained within said stem bore and having a plurality of electrical contacts adapted for connection in an electrical circuit externally of said housing, at least one of said contacts comprising an elongated reed extending in a generally axial direction relative to said stem and movable between open and closed positions relative to another of said contacts, said one contact being within the effective magnetic influence of said magnet during a portion of the movement of said magnet and being movable from one to the other of its positions in response to said magnetic influence to alter the condition of the circuit, and fluid condition responsive means carried by said cam for pivoting said cam in one direction to move said sleeve in response to one fluid condition and for pivoting said cam in an opposite direction to move said sleeve in response to another fluid condition.
8. A fluid condition responsive switch as set forth in claim 7 wherein the axis of said cam intersects said support member axis and is generally normal thereto and said cam is generally symetrical about an axial plane relative to said cam axis.
9. A fluid condition responsive switch as set forth in claim 4 wherein said means for releasably retaining said reed switch comprises a set screw threadably engaging said mounting means.
10. A fluid condition responsive switch as set forth in claim 8 wherein the container comprises a conduit defining a fluid flow path and said fluid condition responsive means comprises a vane extending radially outwardly from said cam and disposed within said conduit, said vane having the surfaces thereof disposed generally transversely of the fluid flow path. 5
11. A fluid condition responsive switch as set forth in claim 8 wherein said fluid condition responsive means comprises a rod attached to said cam and extending generally radially outwardly therefrom and a float mounted on said rod and responsive to the level of the fluid in the container.
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