US1078815A

US1078815A - Limit-switch.

Info

Publication number: US1078815A
Application number: US45057108A
Authority: US
Inventors: Henry J Wiegand
Original assignee: CUTLERHAMMER Manufacturing CO
Current assignee: CUTLERHAMMER Manufacturing Co
Priority date: 1908-08-27
Filing date: 1908-08-27
Publication date: 1913-11-18
Anticipated expiration: 1930-11-18

Description

H. J. WIEGAND.

LIMIT SWITCH.

APPLICATION FILED AUG. 27, 1908. 1,078,815. Patented Nov. 18, 1913.

3 SHEETS-SHEET 1.

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LIMIT SWITCH.

APPLICATION FILED AUG. 27, 1908.

3 BKEETSSHEET 2 Patented Nov. 18, 1913.

H. J. WIEGAND.

LIMIT SWITCH.

APPLICATION FILED AUG. 27, 1908.

Patnted Nov. 18, 1913.

3 SHEETSSHEET 3.

+ l g k UNITED STATES PATENT OFFICE.

HENRY J'. WIEGAND, OF MILWAUKEE, WISCONSIN, ASSIGNOB TO THE CUTLER- HAMEEB MFG. 00., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

LIMIT-SWITCH.

Specification of Letters Patent.

Patented Nov. 13-, 1913.

To all whom it may concern:

Be it known that I, HENRY J. WIEGAND, a citizen of the United States, residing at Milwaukee, in the county of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Limit-Switches, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specification.

My invention relates particularly to limit switches, although certain features thereof are applicable to switches of various other forms.

In limit switches the operating member usually moves at a relatively slow speed, and my invention has for its object to provide means for causing the switches to move quickly from one position to another when actuated by the slowly moving operating member.

A further object of my invention is to provide means for adjusting the switches to ifiierent positions to cause the operating member to actuate the same at any predetermined points in its movement or travel.

A further object of my invention is to provide switches which will be automatically reset upon the reversal of movement of the 0 crating member.

Ot er objects and advantages of my invention will. be hereinafter set forth. For the purpose of more clearly discloslng my invention I have illustrated one embodiment thereof in the accompanying drawings.

Of course, various modifications may be made in the device shown without departmg from the spirit of my invention.

11 the accompanying drawings-Figure 1 is a plan view of the device. Figs. 2 and 3 are enlarged plan views of one of the switches showing the same in open and closed positions, respectively. Fig. 4 is an end elevation of Fig. 2. Fig. 5 is a sectional view taken on line 5-5, Fig. 1. Fig. 6 is an enlarged detail view of the stationary contacts. Fig. 7 is a diagrammatic view illustrating one circuit arrangement for this device.

The several parts of the device are preferably mounted on a supporting base 1 which is provided with lugs or ears Q by means of which the same may be secured to any suitable support. The base 1 is preferably provided with a lon 'tudinally ex tending depression 3 in whic is mounted a shaft 4, the same being journaled in suitable bearings 5 and 6.

Secured to the shaft 4, preferably on the outside of the base l, are collars 7 and 8 which prevent longitudinal movement of said shaft. The shaft 4 is provided with a screw-threaded ortion 9, while the portions thereof, a jacent to said screwthreaded portion, are preferably smooth for the purpose hereinafter'set forth.

At opposite ends of the depression 3 the base is provided with upwardly extendin lugs 10 which support a rod 11. The r0 11 is referably disposed directly above and paral e1 to the shaft 4. Mounted on the screw-threaded portion of the shaft 4 is a traveling nut 12 which is provided with a groove 13 into which the rod 11 fits. The rod 11 forms a guide for the nutr12 and prevents the same from'moving laterally. It will thus be seen that when the shaft 4 is rotated the nut 12 is moved longitudinally on said shaft. The traveling nut 12 is preferably of the she e shown, the corners 14 thereof being beve ed. The lugs 10 also support the rods 15 which are arranged on opposite sides of the shaft 4 and preferably above the same. The rods 15 also pass through lugs 17 which are provided on the base mid-way between its ends.

The several switch mechanisms, which I have shown, are of the. same construction, and I shall, therefore, only describe one of the same.

Each of the switches is mounted on a frame or carriage 19 which preferably comprises a casting to which is bolted an insulating plate 20. On one side the frame or casting 19 is rovided with a tubular portion 21 throng which asses one of the rods 15. On its opposite si e, the frame 19 is provided with a tubular portion 22 (Fig. 5) which is internally screw-threaded and fits onto the screw-threaded portion 23 of the rod 24-. The rod 24 is journaled'in

lugs

25 and 26 provided on the base 1. Secured to the rod 24, on opposite sides of the lug 25, are collars 27 which prevent longitudinal movement of said rod. The rod 24 extends beyond the outer collar. 27 and is provided with a squared end 28, by means of which it may be turned. It will thus be seen that the frame or casting 19 is supported on the

rods

15 and 24, and, therefore, if the rod 24 be rotated the screw-threaded portion thereof will cause the frame or casting to move longitudinally of the base 1 in one direction or the other, according 'to the direction of movement of the rod 24. By means of this adjustment, the position of the switch may be varied to meet different requirements, as will be hereinafter set forth.

Mounted on the screw-threaded portion of the rod 24 is a jam-nut 29 which may be forced against the lug 26 to prevent said rod from turning after the switch has been adjusted to the desired position.

Each of the switches comprises two

members

30 and 31. The member 30 is fulcrumed on a pin 32, carried by the frame or casting 19, While the member 31 is fulcrumed on a pin 33, also carried by the frame 19. The member 30 is provided with an enlarged portion or yoke 34 through which the member 31 extends. The member 31 carries a plate 35 having a beveled edge 36. When the switch members are in the position shown in Fig. 2, the beveled edge 36 of the plate 35 engages the face of a plate 37, carried. by the member 30. Inthe position of the parts shown in Fig. 2, these plates form a latch for preventing relative movement of the

members

30 and 31. These plates are preferably made of hard metal and are detachable so that the same may be readily removed and replaced by new ones when they wear out. The member 31, which I shall hereinafter term the latching member is provided with a tail piece 38 which is preferably flat and carries a conical projection 39. The member 30 is provided with a flattened portion 40 which carries a conical projection 41. Interposed between the tail piece 39 and the member 30, and surrounding the conical projections thereon, is a coil spring 42 which tends to move said members relatively. The action of the spring 42 will be hereinafter more fully described. At its free end, the member 31 carries a roller 43, which, when the members are in the position shown in Fig. 2, projects into the path of the traveling nut 12. The member 31 is provided with an oflset portion 44 which carries a spring buffer 45 against which the member 30 is thrown under the influence of the spring 42 when the members are unlatched. The member 30 carries a roller 46, which, when said member is in the position shown in Fig. 3, projects into the path of the traveling nut 12. On its under side, the member 30 is provided with a contact plate 47 (Fig. 6) which is adapted to engage a pair of contacts 48, mounted in the insulating plate 20, when said member is in the position shown in Fig. 2. The construction of the contacts 48 is best illustrated in Fig. 6. Each of the contacts 48 preferably comprises a button having a stem 49. Each contact is mounted in a tubular casing-50 which extends through the insulating plate 20. The casing 50 is provided with an enlarged portion 51 for receiving the button and a portion of less diameter for receiving the stem 49. The stem 49 extends through the end of the casing and carries two

nuts

52 and 53. Interposed between the button and the end of the casing, 1s a coil spring 54 which tends to force the button outwardly and the nut 52 against the end of the casing 50. It will thus be seen that the nut 52 limits the outward movement of the button, and, therefore, by adjusting said nut the button may be adjusted so as to project the proper distance from the insulating plate. The ends of the stems 49 of the contacts 48 form binding posts by means of which said contacts may be connected in circuit. Suitable

binding posts

55 and 55 are provided on the insulating plate 20.

The operation of each of the switches is as follows: Assuming that the

members

30 and 31 are in the position illustrated in Fig. 2, the roller 43 will project into the path of the traveling nut. It is, therefore, obvious that when the traveling nut strikes the roller 43 the latching member 31 will be turned on its fulcrum and will compress the coil spring 42. As the latching member is turned on its fulcrum, the latching plate 35, carried thereb is gradually moved out of engagement wlth the plate 37 carried by the member 30. As soon as the latching member is moved out of engagement with the member 30, said latter member will fly off of the stationary contacts 48 under the influence of the spring 42, thereby causing a quick break of the circuit. Th movement of the member 30, under the influence of the spring 42, is limited by the spring buffer 45 carried by the latching member. In moving under the influence of the sprin 42 the member 30 forces the latchin mem er into the position shown in Fig. 3, t ereby moving the roller 43 away from the traveling nut. When the member 30 is in the position shown in Fig. 3 the roller 46, carried thereby, projects into the path of the traveling nut, so that when said nut is moved in an opposite direction upon the reversal of the operation of the. motor, it will strike-the roller 46 and cause the member 30 to turn on its fulcrum, thereby again compressing the spring 42. The compression of the spring 42 causes the latchin member to be moved back to the position s own in Fig. 2,

so that when the member 30 has been again moved onto the stationary contacts 48 the plate 35 carried by said latching member, will engage the plate 37 carried by the member 30 and lock said switch member in closed position. It will thus be seen that the traveling nut not only opens each switch, but also resets the same.

While I have illustrated and described the several switches as tending to move quickly to open position, it should be understood that the switches might be arranged to be held in open position and to move quickly to closed position and that such an arrangement would be within the purview of my invention. The device which I have shown for the purpose of illustration is provided with three of these switch mechanisms. It should be understood, however, that more or less of the same may be provided to meet different requirements.

In the diagrammatic view illustrated in Fig. 7, I have also shown three switches, which, for the purpose of distinction, I have designated as B, C and D. In this view the switches B and D are shown closed, while the switch C is shown open. The switches B and D are so adjusted that the traveling nut will open the switch B before it opens the switch D. I shall designate the stationary contacts of the switch B as b and b, the stationary contacts of the switch 'C, as c and 0', and the contacts of the switch D, as d and d. c For the pur ose of illustration I have shown the sha t 4 geared to a motor 56 which may be assumed to operate any mechanism, the travel or movement of which it is desired to limit. Of course, the shaft 4 might be geared to the motor or to an operatin part of the mechanism driven thereby. T e motor 56 is shown diagrammatically as provided with an armature a and a shunt field winding 1''. In this arrangement I have shown a master controller for reversing the motor. The master controller is provided with a controlling arm 57 fulcrumed at 58. The arm 57 preferably comprises two sections insulated from one another. One section carries brushes 59, 60 and 61, while the other section carries a brush 62. Arranged to the right of the arm 57 are

stationary contacts

63, 64 and 65 which are adapted to be simultaneously engaged by the brushes 60, 61 and 62, respect vely, when the arm 57 is moved to the right. Arranged to the left of the arm 57 are a series of stationary contacts 66, 67, 68 and 69. These contacts are so arranged that when the arm 57 is moved to the left, the brushes 59, 61 and 62, carried thereby, will first simultaneously engage stationary contacts 66, 68 and 69, respectively, and when said arm is moved farther to the left the brush 60 will also engage contact 67. I

The circuit arrangement is as follows: The arm 57 is connected to main line 70. Contact 68 is connected by conductor 72 to main line 71, and is also connected by conductor 73 to contact 64. One terminal of the motor armature a is connected by conductors 74 and 75 to contact a of switch C. Contact 0 is connected by conductor 76 to contact 63. The other terminal of the motor armature is connected by conductors 77 and 78 to contact b of switch B. Contact b is connected by conductor 79 to contact 67 of the master switch. Contact 66 is connected by conductor 80 to contact d of the switch D. Contact (3 is connected by conductors 81 and 82 to contact 65 of the master switch. A resistance 83 is connected at one end to conductor 78 and at its opposite end to conductor 82. Contact 69 of the master switch is connected by conductors 84 and 85 to con ductor 74. One terminal of the shunt field winding f of the motor 56 is connected by conductor 86 to main line 70, while the opposite terminal of said winding is connected by conductor 87 to main line 71.

I shall now describe the operation of this system.

Assume that the traveling nut 12 is in the position shown. Under these conditions, 1n order to close the motor circuit it is necessary to move the arm 57 to the left so that the brushes 59, 61 and 62 will engage stationary contacts 66, 68 and 69 respectively.- The armature circuit may then be traced from main line 70 through the arm 57 'by brush 62 to contact 69, by conductors 84,

,field winding being connected across the main lines, will be fully energized when the armature circuit is closed. The motor will thus be started with the resistance 83 in circuit, and, therefore, the same will operate at slow speed. In order to bring the motor up to normal speed it is necessary to move the arm 57 so that the brush 60, carried thereby, will engage contact 67. This results in short-'circuiting the starting resistance 83, and the circuit of the armature may then be traced, as already described, to conductor 77, thence by conductor 78, across switch B, by 'conductor 79 to contact 67, thence to contact 68, and by conductor 72 to main line 71. As soon as the motor is started, the shaft 4 is rotated and causes the traveling nut 12, mounted thereon, to move to the left. In moving to the left the traveling nut 12 first strikes the roller 46, carried by the switch member 30 of the switch C. This results in resetting switch C, as already set forth. As the traveling nut 12 approaches the limit of this movement it first strikes the roller 43, carried by the latching member of the switch B, and causes the switch B to quickly. open, as already described. As soon as the switch B is opened the resistance 83 is again inserted in circuit with the motor AMWMHMPMW armature and causes the motor to slow down. The traveling nut continues to move to the left until it strikes the roller 43 carried by the latching member of the switch D and causes said switch to open. As soon as the switch D opens the motor circuit is opened and the operation of the motor therefore ceases. It is obvious that by adjusting the switches B and D relatively, the motor may be slowed down at any predetermined timebefore the circuit thereof is opened. The

purpose of providing the shaft 4 with smooth portions at opposite ends of the threaded portion thereof, is to prevent the traveling nut from being driven against the ends of the base in the event that the motor continues to operate after the switches have been opened. In order to again start the motor it is necessary to move the arm 57 to the right so that the brushes 60, 61 and 62, carried thereby, will engage

stationary contacts

63, 64 and 65. As soon as the arm 57 is moved to this position, the motor circuit is closed and may be traced as follows: from main line 70, through arm 57 to con tact 65, by conductor 82, through the starting resistance 83, by conductor 77, through the motor or armature, by conductors 74 and 75 to contact 0 of switch 0, across said switch to contact a, by conductor 76 to contact 63,'brush 60, through arm 57 to contact 64, by conductor 73 to contact 68, and by conductor 72 to main line 71. The motor is thus started in an opposite direction. As soon as the motor is set in operation the traveling nut 12 is moved to the right. In

moving in this direction the traveling nutfirst causes the closure of the switch D and then causes the closure of the switch B. Owing to the insertion of the resistance 83, the motor operates at slow speed on the return movement. Of course, if desired, an additional switch might be provided to automatically remove the resistance 83.

It should be understood that the circuit arrangement shown, is merely for the purpose of illustration and that various other circuit arrangements might be worked out 2. In combination, a. pivoted switch tend-- ing to stand in one position, a traveling member adapted, when moved in one dlrection, to engage and move said switch to another position, and an independently pivoted latching member adapted to automatically engage said switch when moved by said traveling member, said traveling member adapted, when moved in an opposite direction, to actuate said latching member to release said switch.

3. In combination, a pivoted switch tending to stand in one position, a traveling member adapted, when moved in one direction, to engage and move said switch to another position, and an independently pivoted latching member adapted to automatically engage said switch when moved by said traveling member, said traveling member adapted, when moved in an opposite direction, to actuate said latching member to release said switch, said switch and said latchin member being adapted, when actuated by said traveling member to move out of the path thereof.

4. In combination, a pivoted switch, a traveling member, said switch tending to stand in a position to project into the path of saidtravelin member and adapted to be moved there y into another position, and an independently pivoted latching member for holding said switch in the position to which it is moved by said traveling member, said latching member being adapted to be engaged and moved by said traveling member to release said switch, said switch and said latching member being .movable alternately out of. and into the path of said traveling member.

5. In combination, a switch tending to stand in one position, means for holding said switch in another position, and a rela tively slow moving member adapted, when in one position, to actuate said means to release said switch and when in another position to return said switch to its former position.

6. In combination, a switch tendin to stand in one position, means for hol ing said switch in another position, and a movable member adapted to be moved in one direction to actuate said means to release said switch and to be moved in an opposite direction to return said switch to its former position.

7. In combination, a switch tendin to stand in one position, means for hol ing said switch in another posit-ion, and a traveling nut adapted, when moved in one direction, to actuate said means to release said switch and when moved in an opposite direction to return said switch to its former position. p 8. In combination, a switch, a latchin member for holding said switch close means for causing said switch to fly to open position when released by said latchin member and a traveling nut adapted, wlIen move in one direction, to actuate salid latching member to release said switch 1,ova,e15

*and when moved in an opposite direction to close said switch.

9. In combination, a pivoted switch, a pivoted latching member for holding said switch in one position and resilient means interposed between said switch and said latching member for moving said switch into another position when said latching member is operated to release the same.

10. In combination, a pivoted switch, a

.pivoted latching member for holding said switch in one position, resilient means interposed between said switch and said latching member for moving said switch into another position when said latching member is operated to release the same, and a traveling member for actuating said latching member.

11. In combination, a pivoted switch, a'

pivoted latchin member for holding said switch in close position, a movable member adapted, when in one position, to actuate said latching member to release said switch, and when in another position to close said switch, and means for causing sa1d switch to fly to open position when released by said latching member and for rollers mounted on said latching member and said switch, and a traveling nut adapted, when moved in one direction, to engage one of said rollers to actuate said latching mem- I her to release said switch and when moved in an opposite direction to engage the other of said rollers toclose said switch.

13. In combination, a switch, a movable member for actuating the same, and means for ad usting said switch bodil to different positions to cause said movabl e member to actuate the same at any one of a number of points in its movement.

14. In combination, a base, a travelin member mounted thereon, a switch mounte on said base to be actuated by said travelin member and means for bodily adjustin sai switch to and retaining the same in dierent predetermined positions on said base.

' 15. In comblnation, a base, a traveling member mounted on said base, a switch slidingly mounted on said base to be actuated by said traveling member and means'for adjustmg said switch to and retaining the same in {31 erent predetermined positions on said see.

16. In combination, a base, a traveling member mounted on said base, a plurality of switches secured to said base to be actuated by said traveling member at difl'erent predetermined points in its movement, each of said switches being bodily movable on said base, and means for individually adjusting said switches to different predetermined positions and locking the same in such positions.

17. In combination, a base, a traveling member thereon, said member traveling in a straight line, a switch mounted upon said base to be actuated by said traveling memher, said switch being adjustable on said base in a line parallel to the line of movement of saidtraveling member and means for adjusting said switch in small degrees.

18. In combination, a base, a traveling member mounted thereon, said member traveling in a straight line, a plurality of switches mounted on said base to be actuated by said traveling member, each of i said switches being adjustable bodily and independently in a line parallel to the line of movement of said traveling member and individual adjusting devices for said switches adapted to adjust the same in small degrees.

19. In combination, a base, a traveling member mounted upon said base and movable in a straight line, a plurality of switches mounted upon said base to betactuated by said traveling member, said switches being adjustable bodily and independently of one another, each in a line parallel to the line of movement of said traveling member, and independent means for adjusting said switches and retaining the same in their adjusted ositions.

20. n combination, a supporting base, a screw-threaded shaft revolubly mounted thereon, a traveling nut mounted on said shaft, means for preventing rotation of said nut, a switch mounted on said base and arranged to project into the path of said nut when in open position, a latching member for holding said switch closed, said latching member being arranged to project into the path of said nutwhen said switch is closed, and means adapted to cause said switch to fly to open position when said travelmg nut actuates said latching member-and to cause said latching member to lock said switch when the same is closed by said nut.

21. In combination, a supporting base, a screw -threaded shaft revolubly mounted thereon, a traveling nut mounted on said shaft, means for preventing rotation of said nut, a switch mounted on said base and arranged to project into the path of said nut when in open position, a latching member for holding said switch closed, said latching member being arranged to project into the path of said nut when said switch is closed, means for adjusting the position of said switch and said latching member to cause said nut to engage the same at any predetermined points in its movement, and means adapted to cause said switch to H to open position when said nut actuates said latching causing the same to fly to open position when screwrthreaded V ber to automatically locksaid switch when 'member and to cause said latching member its movement, and means for causing said -pivoted latchin tolock said switch when by said nut.

22. In combination, a sup Orting base, a screw-threaded shaft revoliibly mounted thereon, a traveling nutm, unted on said shaft, ,means'for prev tinnsaid nut from rotating, a plurality 0-. pi? 'ed switches, a supporting member for each of said switches ad ]ustably mounted on said base, each of sand switches being arranged to project into the path of said nut when in open position, a pivoted latching member for each of said switches, each of said latching members being arranged to project into the path of said nut when its. corresponding switch is closed, and means associated with each switch for the same is closed its latching .member is actuated by said nut and to cause its latchin member to automatically lock the same when moved to closed position by said nut.

23. In combination, a supporting base, a shaft revolubly mounted thereon, a traveling nut mounted on said shaft, means for preventing rotation of said nut, a frame mounted on said base, a switch fulcrumed on said frame and adapted, when opened, to move into the path of said traveling not, a latching member fulcrumed on said frame and adapted to hold said switch in closed position, said latching member bemg arranged to project into the path of said nut when said switch is closed, said frame being adjustable on said baseto cause said nut to actuate said switch and said latchmg member at any predetermined points in switch to fly to open position when said nut actuates said latching member and for causing said latching member to lock said switch automatically when the same is closed.

24. In combination, a switch, a latching member for holding said switch in one position, and means adapted to cause said switch to fly to another position when released by said latching member and to cause said latching member to lock said switch automatically when the same is returned to its former position.

25. In combination, a pivoted switch, a I member for holding said switch in clos position, and means for causing said switch to'flyto open position when said latching member is actuated torelease the same to cause said latching memthe same is moved to closed position.

26. In combination, a pivoted switch, a pivoted latching member for holding said switch in closed position, said latching member being provided with a tail piece, and a spring interposed between said switch and the tail piece of said latching member, said s ring being adapted to cause said switch to y to open position when said latching member is actuated to release the same and to cause said latching member to lock said switch automatically when the same is moved to closed position.

27. In a limit switch, in combination, a base, a member slidably mounted thereon, a switch carried by said sliding member, a traveling device adapted to actuate said switch and a revoluble screw-threaded member adapted to adjust the position of said sliding member upon said base to cause said switch to be actuated by said traveling member at any predetermined point in its movement.

28. In a limit switch, in combination, a base, a traveling nut mounted upon said base and movable in a straight line, amember slidably mounted upon said baseand adapted to slide in a line parallel to the line of movement of said traveling member, a switch carried by said sliding member to be actuated by said traveling member and a revoluble screw-threaded device associated with said sliding member to adjust and hold the same against movement.

29. In a limit switch, in combination, a base, a traveling nut mounted upon said base and movable in a straight line, a member slidably .mounted upon said base and adapted to slide in a line parallel to the line of movement of said traveling member, a switch carried by said sliding member to be actuated by said traveling member, a revoluble screw-threaded device associated with said sliding member to ad ust and hold the same against movement, and a lock-nut for preventing rotation of said screw-threaded member.

30. In a limit switch, in combination, a base, a pair of parallel rods mounted thereon, a switch support mounted upon said rods to move thereon longitudinally thereof, one

of said rods having a screw threaded portion engaging a threaded portion of said switch support, said threaded rod being revoluble to adjust said switch support, a switch carried by said support and a traveling member mounted on said base to actuate said switch, said traveling. member moving I in a line parallel to the line of ad]ustment of said switch support.

31. In combination, an electric motor, a traveling member'adapted to be operated s1- mult-aneously with the motor, a switch connected in the motor circuit and tending to stand in open position, a latching member for holding said switch in a closed position and adapted to be actuated by said traveling member when in a predetermined position to release said switch to quickly open the motor circuit, said traveling member, when moved in an opposite direction, being adapted to close said switch.

. 32. In combination, a switch, a latching member for holding said switch in one position, and means tending to move said switch to another position when said latching member is actuated to release the same and tending to move said latching member to holding position when said switch is moved into the first mentioned position.

i 33. In combination, a switch, a latching member for holding said switch in one position, and a resilient member associated with said switch and said latching member for moving said switch to another position when released by said latching member and for returning said latching member to holding position when said switch is returned to the first mentioned position.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

HENRY J. WIEGAND.

Witnesses: L. D RowiiLL,