US3320374A - Plunger type switch - Google Patents

Description

may 3% 1195? A. R. CHAEAR ETAE.

PLUNGER TYPE SWITCH 5 Sheets-Sheet 1 Filed Dec. 21 1961 ECU r y 1967 R. CHASAR ETAL 3,320,374

PLUNGER TYPE SWITCH Filed Dec. 21 1961 5 Sheets-Sheet 2 N TORJ.

y 16, 1967 A. R. CHASAR ETAL 3,320,374

PLUNGER TYPE SWITCH 3 Sheets-Sheet 5 Filed Dec. 21 1961 United States Patent 3,320,374 PLUNGER TYPE SWITCH Anthony R. Chasar and Alfonso W. Mehrbrodt, Cleveland, Ohio, assignors to The Triax Company, Cleveland, Ohio, a corporation of Ohio Filed Dec. 21, 1961, Ser. No. 161,110 4 Claims. (Cl. 200-47) This invention relates to improvements in a switch assembly and more particularly to a solenoid operated limit switch assembly. The present application is a continuation-in-part of our presently pending application entitled, Solenoid Operated Limit Switch Assembly, Ser. No. 91,020, filed Feb. 23, 1961.

An object of the present invention is to provide a limit switch assembly having an actuator arm moveable endwise between inoperatable and operatable positions with the switch adapted to be actuated in the operatable position.

A further object of the present invention is to provide a limit switch assembly characterized by its inexpensive manufacturing cost, structural simplicity, ease of assembly of its component parts, strong and sturdy nature, low operating cost, operating efficiency, adaptability to use any conventional limit switch, long and accurate switch wear life, etc.

Other'features of this invention reside in the arrangement and design of the parts for carrying out their appropriate functions.

Other objects and advantages of this invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

FIG. 1 is a side elevational view of the limit switch assembly disclosed herein mounted on a supporting frame with the actuator arm thereof shown horizontally in solid lines in inoperatable (retracted) and unactuated position and in dot-dash lines in operatable (advanced) and unactuated position before movement in the actuating direction to the switch actuated positions shown extending diagonally downwardly toward the left in dotted lines;

FIG. 2 is a horizontal sectional view taken generally along the line 22 in FIG. 1;

FIG. 3 is a horizontal sectional view taken generally along the line 33 in FIG. 1 through the pivot shaft of the switch;

FIG. 4 is a vertical sectional view taken generally along the line 4-4 in FIG. 3;

FIG. 5 is a schematic illustration of the interior construction of a conventional limit switch adapted to be used in this assembly;

FIG. 6 is a side elevational view of a second form of limit switch assembly with generally the same actuator arm positions shown as in FIG. 1;

FIG. 7 is a bottom view of the assembly in FIG. 6 taken generaly along the line 7-7 in FIG. 6;

FIG. 8 is a view similar to FIG. 1 and 6 of a third form of the limit switch assembly;

FIG. 9 is a view taken along the line 99 of FIG. 8 of said third form; and

FIG. 10 is a simplified view similar to FIG. 1 showing a roller type actuator arm in a different position.

Before the construction here illustrated is specifically described, it is to be understood that the invention here involved is not limited to the structural details or arrangement of parts here shown since a construction embodying the present invention may take various forms. It also is to be understood that the phraseology or terminology herein employed is for purposes of description an not of limitation since the scope of the present invention is denoted by the appendedclaims.

Those familiar with this art will recognize that this invention may be applied in many ways. One suitable application is to use this limit switch assembly 11 in place of the limit switch assembly having limit switch LS8R in FIGS. 9A and 23 in the copending United States patent application, Ser. No. 66,776; entitled, Mechanical Load Handling, Transfer and Storage Equipment, and filed Nov. 2, 1960, by Anthony R. Chasar, an inventor herein. The operation described herein will be generally the same as in this aforesaid copending application.

Limit switch assembly 119 in FIGS. 1-4 includes switch unit 12, actuator arm 20, and connection or connecting means 22 operatively connecting unit 12 and arm 20. Switch unit 12 has a mounting face 12a and encases any suitable limit switch construction. Such switch unit 12 is shown schematically in FIG. 5 as including by way of example actuatable stationary contacts 13, 13, 14 and 14; and movable contacts 15a and 15b located respectively at upper and lower ends of movable contact plate 15 rigidly carried by arm 19. Arms 19 and 21) are rigidly secured to pivot shaft 24 of connection 22 so that movement of actuator arm 21 by force F from the solid line position to the dotted line position will cause shaft 24, rotatably mounted in the housing of switch unit 12, to move counterclockwise about axis A against the force of spring 18 to move contact plate 15 to the dotted line position to close stationary contacts 14, '14 by movable contacts 15a and 1512 while opening normally closed contacts 13, 13. Upon release of actuating force F on arm 20, spring 18 will return the parts to the solid line position; open contacts 14, 14; and close contacts 13, 13. Actuator arm 20 includes link 26 having rotatably Se.- cured to its distal end a switch actuating, trip engaging roller 28 by pivot pin 99. This limit switch is thus moved from the untripped or Lin-actuated position P1 to the tripped or actuated position P2 by pivotal movement of arm 21) in actuating direction D1. I

This structure thus far described applies generally to any conventional limit'switch, and it should be readily apparent that any satisfactory or conventional limit switch construction may be used within switch unit 12 to be actuated by oscillation of .pivot shaft 24 herein because the schematic construction in FIG. 5 is shown only for purposes of illustration. One suitable form of construction of said switch unit 12 is shown in United States Patent No. 2,352,815, issued July 4, 1944 to H. L. Van Valkenburg, and entitled Electric Switch.

Limit switch assembly 1t) herein is disclosed as being mounted and operable in generally the same manner as the limit assembly, including limit switch LS8R, in FIG. 9A of the copending application. As in this copending application, frame 32 is adapted to be driven in a vertical direction D2 by a suitable motor (not shown) by a circuit through closed contacts 13 in switch unit 12 connected to this supporting frame 32. A stationary frame has located at spaced apart locations along direction D2 a pair of horizontally ali ned stationary frame arms 35 at each location with each arm pair having a trip surface 3ST. Frame 32 carries a load vertically in direction D2; is adapted to be stopped at a preselected trip surface 3ST; and after actuator arm 20 moves to the actuated position P2, suitable mechanism on frame 32 transfers the load onto the shelf provided by the pair of frame arms 35 corresponding to this trip surface 3ST. As frame 32 moves in direction D2, roller 28 engages trip surface 3ST to move the switch components from unactuated position P1 in actuating direction D1 to actuated position P2 in FIGS. 1 and 5 because connection 22 includes a pivot element, comprising pivot shaft 24, pivotally connecting actuator arm 29 to switch unit 12 for arcuate actuating movement of arm 21 in direction D1 about pivot axis A when roller 28 of arm 21 engages with trip 3ST during movement of frame 32 in direction D2 relative to trip 3ST. Movement in actuating direction D1 causes switch contacts 13 to open and contacts 14 to be closed by contact plate 15 in the dotted line position in FIG. 5 upon switch actuation.

Switch unit 12 is connected to supporting frame 32 by securing means comprising two nut and bolt units 38, extending through holes in the housing of switch unit 12 and located at diagonally opposite corners, for securing it onto mounting frame 32.

In the aforesaid copending application, there are a plurality of vertically spaced apart pairs of frame arms 35, and frame 32 is adapted to stop in horizontal alignment with any selected one of these pairs of arms 35 upon movement of actuator arm from unactuated position P1 to actuated position P2. However, during travel in vertical direction D2, it is desirable to keep actuator arm 20 in inoperatable or retracted position P4 during travel past unselected arms and then advance arm 20 to operatable or advanced position P3 immediately before arriving at the preselected arms 35 with which frame 32 is to be stopped in horizontal alignment. This advancing action is provided by the power means mentioned hereinafter having solenoid 62 electrically energized. This electrical energization may be caused in any suitable manner, such as by manually closing an energizing circuit at the appropriate time or by a counter mechanism counting vertically spaced arms 35 or the distance traveled by frame 32 in direction D2, as disclosed in said copending application.

This power means is provided for moving arm 20 relative to frame 32 in direction D4 (non-parallel to actuating direction D1) between inoperatable or retracted position P4 with arm 20 located to be out of actuating alignment with trip 3ST during travel of frame 32 in direction D2 and an operatable or advanced position P3 with arm 20 located to be in actuating vertical alignment with trip 3ST. This power means takes the form of an electrically energizable solenoid 62 for moving arm 20 in direction D4 from position P4 to position P3 upon energization of the solenoid by its lead wires 62a and helical spring 64, or other suitable resilient means, for moving arm 20 in opposite direction D5 from position P3 to position P4 upon de-energization of solenoid 62. Solenoid 62 includes a conventional coil member 62b having telescoped therein relatively movable armature member 62c movable in direction D4 upon energization of coil 62b.

The power means moves arm 20 relative to switch unit 12 and pivot element in direction D4 or D5 between positioned P3 and P4. Solenoid 62 and spring 64 is constructed so that each operatively connects arm 20 and pivot element 45 of switch unit 12. Connection 22 may take any suitable form and includes herein pivot element 45 pivotally connecting actuator arm 20 to switch unit 12.

As will be apparent hereinafter, and by consideration of the drawings, the description of the structure and mode of operation in the preceding paragraphs also applies generically to the same named or numbered parts, positions, directions and movements in FIGS. 6 and 7.

Pivot element 45 includes pivot shaft 24 extending from switch unit 12; bracket 47 secured to shaft 24 against rotation by clamp screw and nut unit 43; parallel guide grooves 49 in bracket 47 to slidably receive parallel portions 26a of link 26 of arm 20 for movement generally perpendicular to pivot axis A, in direction D4 or D5, and endwise of arm 20; and solenoid mounting plate 52 secured by mounting screws 50 and 51 extending respectively through holes in bracket 47 and plate 52 and in plate 52 to be screwed into threaded holes in frame housing 62d of solenoid 62 in FIG. 3. Solenoid 62 has armature member 62c secured at its outer end to links 26 of arm 20 by one end of link 70 extending into slot 62c cut in the end of armature 62c and secured therein by pin 61 extending through aligned holes in link 70 and armature 62c and has its other end straddling slit tubing 72, preferably of Nylon to resiliently cushion the operation, sprung over vertically extending connecting portion 260 joining vertically spaced apart and horizontally extending link portions 26a of link 26. Spring 64 has its opposite ends secured to mounting screw 51 on bracket 47 and through a hole 26f in link 26 of arm 20 with spring 64 located generally coplanar with link 26 of arm 20.

In FIGS. 6 and 7, limit switch assembly is shown. Connection or connecting means 122 may take any suitable form and includes herein pivot element pivotally connecting actuator arm 20 to switch unit 12. Pivot element 145 includes pivot shaft 24 extending from switch unit 12; bracket 147 secured to shaft 24 against rotation by clamp screw and nut unit 48; parallel guide grooves 149 in bracket 147 to slidably receive link 26 of arm 20 for movement generally perpendicular to pivot axis A, in direction D4 or D5, and endwise of arm 20; and mounting screws 150 and 151 extending through holes in bracket 147 and screwed into threaded holes in frame housing 62d of solenoid 62 in FIG. 7. Solenoid 62 has armature member 62c secured at its outer end to link 26 of arm 20 by one end of link extending into slot 62c cut in the end of armature 62c and secured therein by pin 61 extending through aligned holes in link 170 and armature 62c and has its other end secured to link 26 by screw 181 extending through an aligned hole in link 170 and slot 26d (see FIGS. 3 and 4) in link 26, formed by link portions 26a and 26c. Screw 181 is secured to link 26 against endwise movement by assembled square washer 182, nut 183 and lock washer 184. Spring 164 is a helical spring telescoped over armature member 62c between coil member 6211 and washer 185 telescoped over Link 170 and abutted against the end of armature 620.

The construction in FIGS. 6 and 7 has the advantages of eliminating solenoid mounting plate 52 in FIG. 3, conveniently locating spring 164, and providing maximum horizontal bearing length for link 26 in guide grooves 149 in FIG. 7.

It should be noted that when the parts in FIGS. 1-4 and 6-7 are in the operatable or advanced position P3, the components of the power means are so located to minimize the retarding inertia caused by their weight during arcuate movement of arm 20 about axis A in actuating direction D1 during switch actuation from position P1 to position P2. Solenoid 62 and spring 64 or 164 are connected to move with and to have the same arcuate actuating movement in direction D1 about axis A as arm 20 and are carried near pivot axis A to minimize the retarding inertia.

The advantages of the construction in FIGS. 1-4 and 6-7 are many, and especially when used in the circuit disclosed in the aforesaid copending application. First, a conventional limit switch, having arm 20 secured against endwise movement to bracket 47 by lock plate 52 secured to bracket 47 by screw 50, can be easily converted to the design in FIGS. 1-4 by merely adding solenoid 62 having armature slot 62c, spring 64, link 70, pin 71, slit tubing 72, screw 51, and by deepending guide grooves 49 to give the sliding action of arm 20 in directions D4 and D5. Second, longer and more accurate wear life is obtained by switch unit 12 because arm 20 is normally in position P4 so does not have to be overworked by engagement and actuation by every trip surface 3ST but is only extended to operatable position P3 at the preselected trip 3ST to be actuated only once where desired. Third, no holding contacts are required in the operating circuit in parallel with contacts 13, 13 to maintain energized the driving motor of frame 32 as switch umt 12 is actuated by each trip 3ST before the selected stopping position is reached. Fourth, one can select,

either manually or by suitable counting mechanism, the time to advance arm 20 from position P4 to position P3 for actuation in direction D1 from position P1 to position P2 at the desired trip surface 3ST so that undesired trips 3ST may be passed during movement of frame 32 in direction D2 without switch actuation. Fifth, this limit switch assembly or 110 may be usedfor many different purposes in addition to that disclosed in the aforesaid copending application, such as on hoisting devices, conveyors, count-ing devices, sorting devices, etc. Sixth, frame 32 can be caused to continue movement in direction D2 after being stopped in position P2 in a very simple manner by this construction. De-energizing solenoid 62b will cause spring 64 or 164 to move arm from position P2 to position P4 to close contacts 13 and permit travel of frame 32 in direction D2 in the same manner as earlier described. Sixth, swinging arm 20 in actuating direction D1 is easily done with minimum force because of the low inertia construction previously mentioned as resulting from the structural location of solenoid 62 close to axis A.

The third embodiment of the invention as illustrated in FIGS. 8-10 represents a further refinement of the switch assemblies of the first two embodiments. The third embodiment comprises a switch unit 200 mounted to a vertically movable load carrying frame 201 by suitable bolt and nut units'203 in .the same manner as shown in the previous embodiments. -A pivot shaft 204 projects laterally and horizontally from the switch unit 200 the pivoting of which actuates contacts within said unit in a manner similar to that illustrated in FIG. 5. A clamp element 205 is telescoped over the pivot shaft 204 and is rigidly but adjustably fixed thereon by a conventional set screw and nut unit 206.

A housing 207 is mounted to the clamp element 205 by a plurality of bolts 208 which project through suitable apertures in said clamp and are thread fitted into the housing wall, and said housing contains a solenoid coil 209 which is axially disposed at right angles to the axis of the pivot shaft 204. As in the previous embodiments, the coil 209 and housing 207 pivot with the pivot shaft 204 due to their rigid attachment to said shaft by the clamp element 205 and the bolts 208. An armature bar 210 is disposed coaxially through the coil 209 and extends in either direction beyond said coil through suitable openings in the ends of the housing 207.

As best shown in FIG. 8, the armature bar 210 is normally disposed in horizontal position when the switch unit 200 is unactuated with one end portion 210a of said bar extending in the direction of, but short of arms 211 of a storage frame, and the opposite end portion 21012 of said armature projecting a substantial distance beyond the housing 207 in the opposite direct-ion. The end portion 21% carries a washer 212 adjacent the distal end thereof which is retained upon said bar by a transverse retainer pin 213 projecting through a suitable transverse aperture in said bar and extending radially outwardly therefrom. A coil spring 214 is telescoped over the bar 210 and is disposed between the housing 207 and the washer 212 in such manner as to bias the bar in a retracted direction away from the arms 211 of the storage frame. The armature bar is restricted in its retracted movement by a transverse stop pin 215 which is disposed through a suitable aperture in said bar to normally engage the opposite end of the housing 207 to hold said bar in a predetermined retracted position.

In operation, the solenoid coil 209 is energized during the upward movement of the frame 201 at the approach position to the arms 211. The coil forces the armature bar forwardly or in the direction of said arms thereby overcoming the bias of the spring 214 and causing the end portion 210a to be positioned beneath one of the arms 211. As illustrated in FIG. 8, the full line showing of the armature bar 210 illustrates said bar in the retracted position whereas the broken line showing of said bar indicates its extended position. The vertical broken line X on the arm 211 indicates a possible position of the distal end of said arm if for any reason it is not positioned the exact desired distance away from the frame 201. If this variation exists, it will be noted that the end portion 210a of the armature bar still contacts the bottom of the arm at exactly the same level as it would if said arm were in the proper, full-line position. The horizontal broken line Y on the frame 201 represents, for the purpose of illustration, an arbitrary plane through said frame which should be coplanar with the top surfaces of the arms 211 at the moment of contact between the end portion 210a and said arm in order to bring the moving frame to a stop in perfect horizontal alignment with said arms. It will be noted that the line Y would represent the same level for initiating a stopof movable frame 201 relative to the top surfaces of the arms 211 throughout substantial variation in the horizontal distance between the distal ends of said arms and the movable frame.

FIG. 10 shows, by way of contrast, that when the distal ends of the arms 35 are spaced away from the frame 32 beyond a vertical plane through the axis of the roller 28 in its extended position, said roller does not contact an arm 35 until the line or plane Y has moved a substantial distance above the top surfaces of said arms. The condition as illustrated in FIG. 10 would, therefore, effect a delay in the actuation of the switch unit (200 in such manner as to cause the movable frame 32 to stop in a position above the desired position and out of alignment with the storage frame arms. The improvement of FIGS. 8-10 thus effects a switch unit which maintains its accuracy in stopping the movable frame throughout more varied conditions of frame position than those units shown in the first two embodiments.

The third embodiment of the invention also provides the improvement of simplified construction which obviates the need for a separate actuator arm as shown at 20 in the prior embodiments. In the last described form, the solenoid coil is enabled to work more positively due to the fact that only the armature is moved by energization of the coil, and all of the mass of the material to be moved is concentrated at the axis of the coil thereby greatly facilitating its pulling effort.

Various changes in the details and the arrangement of parts may be made by one skilled in the art without departing from either the spirit of this invention or the scope of the appended claims.

What is claimed is:

1. In an apparatus comprising a fixed member and a movable member movable into alignment with said fixed member; a switch unit carried by said movable member in use in normally unactuated position and actuatable to effect stopping of said movable member, said unit having a pivot shaft pivotable to effect actuation of said unit, a solenoid fixedly mounted upon said shaft and axially disposed at right angles to said shaft, an elongated armature bar slidably disposed through said solenoid and ex tending t-herebeyond in either direction, said bar having a retainer adjacent one end and a stop adjacent the other end thereof, a coil spring telescoped over said bar between said retainer and said solenoid and normally urging said bar in a retracted position with said stop engaging said solenoid .to limit the retraction of said bar, said solenoid so acting, when energized, as to move said bar in an extended position to cause contact of said arm with said fixed member and cause pivoting of said shaft as said movable member approaches said fixed member.

2. In an apparatus comprising a fixed member and a movable member movable to a selected position relative to said fixed member; a switch unit carried by one of the members in use in normally unactuated position and actuatabie to effect stopping of said movable member, said switch unit having a pivot shaft pivotable to effect actuation of said switch unit, a solenoid coil mounted upon said pivot shaft and disposed axially at right angles to said shaft, an arm disposed parallel with the axis of said coil and operatively connected to said coil in such manner as to be extensible relative to said shaft in response to energization of said coil, said arm optionally extensible by said coil to an extended position in alignment with said other member whereby said other member contacts said arm and pivots it as said movable member approaches said fixed member to stop said movable member in said selected position.

3. Switch leveling means comprising a vertically movable frame, a plurality of vertically aligned, spaced trips disposed adjacent to the path of movement of said frame, a switch mounted to said frame adjacent to said trips for stopping said frame upon actuation thereof, said switch having a pivot shaft pivotable to effect actuation of said switch, a solenoid coil mounted upon said shaft and disposed axially at right angles to said shaft, an actuator arm disposed parallel with the axis of said coil and coplanar with said trip, said arm operatively connected to said coil in such manner as to be extensible into vertical alignment with said trips in response to energization of said coil, spring means biasing said arm toward a retracted position out of alignment with said said trips, said arm optionally extensible by said coil to be tripped by a selected one of said trips as said frame moves vertically whereby said arm will pivot said shaft and actuate said switch to cause said frame to stop adjacent to said selected trip.

4. Switch leveling means as set forth in claim 3; said actuator arm comprising an elongated armature bar slidably disposed through said coil and extending therebeyond in either direction, said bar having a retainer adjacent to one end and a stop adjacent to the other end thereof, said spring means comprising a coil spring telesooped over said 'bar between said retainer and said coil and normally holding said bar in said retracted position with said stop engaging said coil to limit the retraction of said bar, said coil, when energized, moving said bar endwise against the bias of said spring and causing said bar to move into alignment with said trip.

References Cited by the Examiner UNITED STATES PATENTS 842,630 1/1907 Cooper 18736 1,531,428 3/1928 Way 187-3l 2,499,979 3/1950 Smith 187-52 2,767,269 10/1956 Kerr 200-47 2,906,842 9/1959 Brin 200172 2,927,310 3/1960 Knapp 200-61.42 X 2,990,725 7/1961 King 20047 ROBERT K. SCHAEFER, Primary Examiner.

H. HOHAUSER, S. SIMON, Assistant Examiners.

Claims (1)

1. IN AN APPARATUS COMPRISING A FIXED MEMBER AND A MOVABLE MEMBER MOVABLE INTO ALIGNMENT WITH SAID FIXED MEMBER; A SWITCH UNIT CARRIED BY SAID MOVABLE MEMBER IN USE IN NORMALLY UNACTUATED POSITION AND ACTUATABLE TO EFFECT STOPPING OF SAID MOVABLE MEMBER, SAID UNIT HAVING A PIVOT SHAFT PIVOTABLE TO EFFECT ACTUATION OF SAID UNIT, A SOLENOID FIXEDLY MOUNTED UPON SAID SHAFT AND AXIALLY DISPOSED AT RIGHT ANGLES TO SAID SHAFT, AN ELONGATED ARMATURE BAR SLIDABLY DISPOSED THROUGH SAID SOLENOID AND EXTENDING THEREBEYOND IN EITHER DIRECTION, SAID BAR HAVING A RETAINER ADJACENT ONE END AND A STOP ADJACENT THE OTHER END THEREOF, A COIL SPRING TELESCOPED OVER SAID BAR BETWEEN SAID RETAINER AND SAID SOLENOID AND NORMALLY URGING SAID BAR IN A RETRACTED POSITION WITH SAID STOP ENGAGING SAID SOLENOID TO LIMIT THE RETRACTION OF SAID BAR, SAID SOLENOID SO ACTING, WHEN ENERGIZED, AS TO MOVE SAID BAR IN AN EXTENDED POSITION TO CAUSE CONTACT OF SAID ARM WITH SAID FIXED MEMBER AND CAUSE PIVOTING OF SAID SHAFT AS SAID MOVABLE MEMBER APPROACHES SAID FIXED MEMBER.

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