US1964199A

US1964199A - Electric control device

Info

Publication number: US1964199A
Application number: US647951A
Authority: US
Inventors: Clarence T Evans
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1932-12-19
Filing date: 1932-12-19
Publication date: 1934-06-26
Anticipated expiration: 1951-06-26

Description

June 26 1934 c. lT. EVANS 1,964,199

ELECTRLQ csNTfvr. DEVICE Filed Dec/19,

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ELECTRIC CQNTBOL DEVICE Clarence T. Evans. Wauwatosa, Wis., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a cor- Dotation oi Delaware Application December 19, 1932, Serial No. 647,951 8 Claims. (Cl. 209-4) Thisinvention relatestoelectric control devices,

tacts

1 and 2 is provided with an inverted L- and while not limited thereto is particularly apshaped bracket 15 iixed to the front face of inplicable to frictionally operated switches for use sulating base 12 by a terminal device 16 including in alternating current motor control systems to a securing screw located within an opening in effect control of plugging connections. said insulating base, as shown in Fig. 4. The 00 The invention has among its objects to provide brackets 15 have contact tips 17-l7 fixed to the an improved frictionally operated switch for use upper ends thereof, and the movable contact elein systems of the aforesaid character which is of ment 3 is provided with a support 18 having consimple, rugged and compact construction. tact tips 19-19 mounted upon the lower face 1:) Another object is to provide a switch of the thereof to cooperate with the former contact tips. 65-

aforesaid character having novel and eillcient Thel upper face of contact support 1B is provided friction operating means associated therewith, with spaced lugs 20-20 having openings therein Various other objects and advantages of the for receiving pivot pin 4, and as shown in Fig. 3 invention will hereinafter appear. Ybelt 6 is secured to opposite ends of said contact 15 The accompanying drawing illustrates an emsupport by screws 2i having clamping plates 22 70 bodiment of the inventionwhich will now be deassociated therewith. scribed, it being understood that the embodiment The spring pressure device 8 includes a vertiillustrated is susceptible oi' modification without cally arranged pin 23 carried by a bracket 24 departing trom the spirit and scope of the fixed toinsulating base 12 by screws 25. Pin 23 is 2Q appended claims. slidably` mounted within openings in spaced for- 75 In the drawing, wardly extending

lugs

26 and 27 on bracket24, Figure l is a front elevational view of an enand the upper end of said pin is located within closed frictionally operated switch embodying the an opening in pivot pin 4 and is provided with invention, the. cover of the enclosing casing being an enlarged head 29 for engaging said pivot pin removed. Y on the upper side thereof. Pin 23 is biased to 80 Figs. 2 and 4 are vertical sectional views taken move downwardly by a coiled spring 30 which suron lines 2-2 and 4 4. respectively, of Fig. 1. rounds said pin and is held under compression Fig. 3 is an enlarged fragmentary view,'partly between a washer 31 which abuts the upper lug 26 in section, of certain of the .switch parts shown in on bracket 24. and a washer 32 which abuts'a ,o Fig, 1 cotter pin 33 located within an opening in pin 23. 85

Pig. 6 ditically illustrates the switch As shown in Fig. 3y the contact support 18 is slotas applied to a plllsins control system i'or inducted at 34 to clear the pin 23, and for a purpose tion motors. hereinafter set forth the under side of said sup- The control switch illustrated in the drawing port is provided with a fiat face 35 for coopera- -35 includes spaced stationary contacts l and 2, and tion with the top face of the upper lug 26 on 90 a cooperating movable contact element 3 pivotbracket 24. ally mounted at a point intermediate said sta- As hereinbefore stated, the drive shaft 'l is rotionary contacts' upon a pin 4. 'I'he operating tatably mounted within a bearing 14'provided in mechanism for contact element 3 comprises a the upper end ofcasing 9. As shown in Fig. 2 the o pulley 5 and a belt 6 looped over said pulley and bearing 14 includes spaced ball bearings 36- and 95 connected to opposite ends of said contact ele- 37 having their inner races mounted upon shaft 'I v ment, said pulley being fixed to a drive shaft '1, and having their outer races supported within a and said belt beingheld under tension by a spring hollow cylindrical projection 38 extending for-'1 pressure device 8 associated with pivot pin 4. wardly from thejrear wall of casing 9. Shaft 7 The aforementioned switch parts are mounted and its associated ball bearings are held in aswithin a box shaped enclosingcasing 9 provided sembied relation within projection 38 by a rewith a removable cover 10 which is secured to said taining ring 39 tlxed to the rear wall of casing 9 casing by screws 1l,` shown in section in Pig. i. by screws40. and said shaft has a portion pro- An insulatinbase 12 xedto the rear wall of Jecting rearwardly beyond said retaining ring casing 9 by screws 13 carries stationary contacts for connection to a driving part such as the shaft 105 1 and2.m0vble WDM elmnt 3.*Ddthe Spring of a reversible electric motor. An opening 41 pressure device 8, and the drive shaft 'l is rotathaving a removable screw plug 42 associated ably mounted-within a bearing 14 provided in the therewith is provided for introducing a lubricant upperend ofsaidcasing. l to thel

ball bearings

36 and 37, and to Vprevent More speciiically, each of the stationary con-y leakage of the lubricant a projecting hub portion 110 i3 on pulley 5 ts within a grooved opening in the front end of the hollow cylindrical projection 3S and shaft '7 lits within a grooved opening in retaining ring 39.

The function and operation of the aforedescribed device will now be more fully described. As is apparent, the spring pressure device 8 tends to .move the contact support 18 into the position shot/'n in dotted lines Fig. 3. However, the belt is of such length es to hold Contact support i8 in an elevated position, and the belt is thereby placed under tension by the spring pressure de vice il. Thus the belt provides a slip driving connection between pulley 5 and the movable contact element 3. As is apparent from Figs. l and 3,

upon rotation of pulley 5 in a clockwise direction 'the movable contact element 3 is maintained in engagement with stationary contact 2 and out of engagement with stationary contact l, and upon rotation of said pulley in a counterclockwise direction said movable contact is maintained in engagement with stationary contact l, and out of engagement with stationary contact 2. Also as is apparent from Figs. l and 3, upon a change in the direction of operationof pulley 5 the movable contact element 3 is immediately tilted upon its pivot pin Il to change the position thereof. In connection with the foregoing it should be noted that if +he belt 6 breaks or slips oil of the pulley 5 spring pressure device 8. moves the contact elenient 3 into the position shown in dotted lines in B, and in this position the face on contact support i8 engages the top lface of the lug 26 on bracket 2e to maintain said contact element out oi engagement with its cooperating stationary contacts l and 2.

The above described device may beused in a system suoli as shown in Fig. 5 to control plugging of a three phase induction motor M. In the systein shown in this iigure the supply circuit for the motor is indicated by lines Ll-L2-L3, and electroresponsive switches F and R are provided for selectively establishing forward and reverse power connections for the motor. The energizing circuit for the operating winding of switch F is controlled by a manually operated switch and the above described irictionally operated switch is connected to the shaft of motor M and is arranged to control the energizing circuit of switch F through the medium of normally closed auxiliai'y contacts 46 associated with switch F. As is apparent from Fig. 5, closure of switch 45 effects response of switch F by connecting the operating winding of said switch across lines L1L2. Switch F establishes power connections for motor M to cause rotation thereof in a direction to maintain the contact element 3 in engagement with its cooperating stationary contact 2. Opening of switch 45 deenergizes switch F and immediately upon dropping out of said switch, switch Pt is energized by a circuit extending from line L1 through the operating winding of said letter switch, through stationary contact 2 and movable contact 3 ci the frictionally operated switch and auxiliary contacts 46 of switch F to line L2. Switch R in responding establishes reverse power connections for the motor to effect plugging thereof. At the instant the motor reverses under the action of said reverse power connections contact element 3 moves out of engagement with stationary contact 2 to interrupt the energizing circuit for switch R, whereupon the motor is brought to rest.

As shown in Fig. l, the lower screw 25 associated/with bracket 24 is connected to the movable contact element 3 by a flexible lead 47 and serves as a Wiring terminal for said contact clement. Also as shown in Fig. l one of the side walls of casing 9 has a wiring opening 48 therein, and the rear wall of said casing has openings 49 therein through which bolts may be passed for securement of the device to a suitable support.

What I claim as new and desire to secure by Letters Patent is:

l. In a frictionally operated switch, the combination with a contact element movable in op posite directions between given circuitcontrolling positions, of a driving pulley therefor, a belt looped over said driving pulley and connected to said contact element to provide a slip operating connection for frictionally holding said element in one position upon rotation of said pulley in one direction, and to move the saine into its op` posite position upon initial rotation of said pulley in a reverse direction and spring means to effect tensioning of said belt.

2. In a frictionally operated switch, the combination with a Contact element movable in opposite directions between given circuit-controlling positions, of a driving pulley therefor, a frictional operating connection between said pulley and said element to frictionally hold said element in one of said positions upon rotation of said pui ley in one direction and to move the same into its opposite position upon initial rotation of said pulley in a reverse direction, and means for bies ing said element to insure positioning thereof in an intermediate position but only upon failure of said frictional operating connection.

3. In a frictionally operated switch, the combination with a contact element movable in opposite directions between given circuit controlling positions, of a driving pulley therefor, c. belt looped over said pulley and connected to said Y Contact element to provide a slip operating connection for frictionally holding said element in one position upon rotation of said pulley in one direction, and to move the same into its opposite extreme position upon initial rotation o! said pulley in a reverse direction, and spring means associated with said element for biasing the same to effect tensioning of said belt.

4i. In a frictionally operated switch, the combination with a pivoted Contact element movable in opposite directions between given circuit-controlling positions, o! a driving pulley therefor, a belt looped over said pulley and operatively connected to said contact element on opposite sides of the pivot thereof, and a. spring pressure device for biasing the pivot o1' said contact element in a direction to effect tensioning of said belt.

5. In a frictionally operated switch, the combination with a pair of stationary contacts and a cooperating movable contact element having an associated pivot pin arranged intermediate said stationary contacts, of a reversible driving pulley, a belt looped over said pulley and connected to said contact element on opposite sides of said pivot pin to provide a slip operating connection for moving said Contact element into and out o! engagement with one or the other of said stationary contacts in accordance with the direction of rotation of said pulley, a spring associated with said pivot pin to bias said contact element in a f direction to effect tensioning of said belt, and a xed stop, said Contact element being movable into engagement with said stop under the aci-ion of said spring upon failure o! said belt, to insure movement of said contact into out nection for moving said contact element into andout of engagement with said stationary contact upon rotation of said pulley in opposite -direc.

tions, a spring associated with said pivot pin to bias said contact element in a direction to en'ect tensioning of said belt, and a fixed stop for limiting movement of said contact element under the action of said spring upon failure of said belt, said stop and said contact element having cooperating surfaces which insure'movement of said contact element out of engagement with said stationary contact upon failure of said belt. A

7. In a frictionally operated switch, in combination, an enclosing casing, an .insulating base mounted within said casing, a switch mechaf nism mounted upon said base, including a sta.-

tionary contact and a cooperating movable contact element having a pivot pin associated therewith, a pulley within said casing having an associated drive shaft Journaled in one of the walls of said casing, a belt looped over said pulleyand connected to said contact element on opposite sides of its associated pivot pin toprovidev for of engagement with said stationary contact upon rotation of said pulley in opposite directions, and a spring pressed pin slidably mounted upon said insulating base and connected to the pivot pin associated with said contact element to bias the latter in a direction to effect tensioning of said belt.

8. In a frictionally operated switch, in combination, an enclosing casing, an insulating base mounted upon the rear wall of said casing, a

switch mechanism mounted upon said base including a stationary contact and a cooperating movable contact element having a pivot pin associated therewith, a. pulley within said casing having an associated drive shaft journaled in the rear wail of said casing, a belt looped over said "pulley and connected to said contact element on opposite sides of its associated pivot pin to provide for movement of said'contact element into and out of engagement with said stationaryv contact upon rotation of said pulley in opposite directions; a bracket mounted 'upon said insulating base, a spring premed pin slidably mounted upon said bracket and connected to the pivot pin associated with said contact element to bias the latterin a direction to eifect tensioning of said belt.' said contact element and said bracket having cooperating surfaces adapted to engage upon failure of said belt toinsure disengagement of said a contact element with said stationary contact. v y y CLARENCE T.

fics.