US1760763A - Electric-circuit-control means - Google Patents

Description

May 27, 1930. A. J. MAY 1,7 ,76

ELECTRIC CIRCUIT CONTROL MEANS Original Filed Nov. 20', 1925 3 Shgets-Sheet l 1:15 T NEYS M ay 27, 1930., A. J. MAY 1,760,763

ELECTRIC CIRCUIT CONTROL MEANS Original Filed Noy. 20, 1925 3 Sheets-Sheet 2 l l l l.

INYENTOR May 27, 1930. A. J. MAY 1,760,763

ELECTRIC CIRCUIT CONTROL MEANS I Original Filed Nov. 20, 1925 S Sheets-Sheet 3 INVENT R {b/ Patented May 27, 1930 UNlTE SATES r rice ADAM J". MAY, OF ROCHESTER, NEW'YOR-K, ASSIGNOE, BY MESNE ASSIGNMENTS, TO THE BITTER DENTAL IJIANUFACTURING COMPANY, INC., OF ROCHESTER, NEW

YORK, A CORPORATION GF DELAVIARE ELECTRIC-CIRCUIT-CONTROL MEANS Original application filed November 20, 1925, Serial No. 70,241. Divided and this application filed September 10, 1928.

The present invention relates to electric circuit control means and has for one object to provide improved means of this class for controlling electric motor circuits and particularly to an improved limit switch having a plurality of different circuit closing positions to which it is adapted to be moved automatically by one or more parts driven by the motor such as an extensible chair section.

A further object of the invention is to provide an improved limit switch for electric motor circuits having a plurality of different operating positions, the switch being under the control of an extensible chair section for moving it to and from said positions whereby to control the movements of said chair section.

A still further object of the invention is to provide in conjunction with a movable chair section having a reversible motor for operating the same and a manually controlled two-way switch, an automatic-chair controlled limit switch with circuit connections so arranged that the limit switchwill have one closing position common to both closing positions of the two-way switch and two other positions, in each of which 'it is adapted to open the motor circuit with the main switch in one operating position and to close it with the main switch in another operating position.

To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings Figure 1 is a diagrammatic view illustrating the circuit arrangement of an A. C. and D. C. motor together with the switches therefor in connection with a part sectional plan of the chair base showing the several junction boxes for the switches and a conduit for enclosing the circuit connections;

Figure 2 is a diagrammatic view in elevation illustrating a portion of an extensible chair with the operating pins or projections for the limit switch shown on one of the adj ustable sections;

Serial No. 134,741.

contact member in central position and illustrating one position of the switch operating projections on the outer movable section of the chair.

Figure 8 is a similar section showing the switch after operation by the chair to one of its circuit breaking positions; and V Figure Q is a sectional plan taken on line 99 of Figure 6.-

Similar reference numerals throughout the several views indicate the same parts.

The invention disclosed herein embodies an improved electric circuit control mechanism, the present application being a division of'my (to-pending application for extensible chairs filed November 20, 1925, SerialNo. 70,241.

The invention contemplates the provision of a manually controlled electric switch and an automatic limit switch connected theretoand adapted for control bya movable part as for example, an extensible chair section.

Referring to-the drawings, 11 represents a chair base carrying an A. C. or D. C. motor 11 adapted for connection with a suitable lifting mechanism for the chair, not shown, such as that disclosed in my co-pending application referred to above for raising and lowering the inner and outer extensible chair sections12 and 13, respectively, the latter being guided by the base 11 and the former by the outer section 13 in a well-known manner. A foot pedal 14: is provided on the base for operating the motor reversing switch, indicated generally at 15 in Figure 1 and adapted to be disposed in a pocket or junction box 15 in the base 11. The motor reversing switch 15 is preferably the same as that disclosed in the application referred to above. Connected with the reversing switch is an automatic limit switch, indicated generally at 16 in Figure 1 and in detail in Figures 3 to 9, inclusive, the same being arranged for disposal in a pocket 16 and the base 11. The pockets 15 and 16 are provided with cover plates 15 and 16, respectively, as shown in Figure 2. A line switch 17 is also provided, the same being adapted for disposal in a pocket 17 in the chair base.

The A. C. and D. C. motors are indicated diagrammatically at 18 and 19, respectively. Each of the motors is preferably provided with two plug and socket connections 20 and 21, which may be combined in a single connection if desired. The sockets are preferably carried by the motors and the fingers 22 which take into the sockets are adapted to project from a holder 23 on the free end of a conduit 24 through which the circuit connections extend to the junction box 15 for connection with the switch plate 25 as shown in Figure 1. In this figure the heavy lines indicate a closed oractive circuit through the A. C. motor while the light lines indicate, in part, the cir: cuit arrangement for the D. C. motor, certain of the wires being common to both circuits. The circuit for the A. 0. motor is shown closed through the limit switch 16 with the latter in the position shown in Figure 8, after it has been actuated from the position shown in Figure 7 by the downward movement of the chair to approximately its lowest position.

The limit or automatic control switch 16 is adapted to be actuated by one of the adjustable sections of the chair in its up and down movements, preferably the outer section 13, through the medium of suitable parts associated therewith, such as the upper and lower pins or projections 26 and 27 respectively, in the path of which is located the controlling means for the limit switch which will presently be described.

The limit switch embodies inner and outer switch plates 28 and 29, respectively, which are constructed of suitable insulating material and between which is disposed a metal plate 30, the several plates being connected by suitable bolts or screws 31 as shown in Figures 3 and 4. The inner plate 28 is provided with an undercut groove or recess 32 in which is guided a slide block 33, which is dove-tailed on its outer face to receive the laterally projecting portion 34 of a holder 35 comprising a plate of insulating material having on its inner face a contact bar 36 secured by screws 37. The contact bar 36 is adapted for reciprocation in an elongated recess 38 formed in the plate 29 as shown in Figures 3 and 4. Mounted on the inner face of the plate 29 are three fixedcontacts 39, 40 and 41 which extend within the recess 38 in the path of the movable contact 36 for engagement therewith, the latter having three different operating positions corresponding to different positions of the chair as will be subsequently explained. The fixed contacts are each suitably secured to the plate 29 as by means of the studs 42 which preferably carry the binding posts 43 for the several wires 39 40 and 41 connected with said contacts as shown in Figures 1 and 3. The fixed contacts of the reversing switch 15 shown in Figure 1 include plugs l to 5 inclusive adapted to take into sockets at one end of the plate 25 and also include plugs 6 to 10 inclusive adapted to take into sockets at the opposite end of the plate. The connection 39 leads to socket for the plug 5 of the switch plate 25 and the opposite connection 41 to socket for the plug 10, each of said connections being adapted in conjunction with the connection 40 to complete the motor circuit when the starting switch is moved to closed position.

The slide 33 is recessed to form a housing 44 for a spring 45 having its opposite ends engaging follower plates 46 and 47 located within and being free to move inwardly of the housing. The followers are each held against outward movement by end closures 48 of the housing. Projecting through the housing and through the spring therein is an operating stem 49 provided at one end with a head 50 engaging the follower 46 as shown in Figure 6. The stem is provided at its other end with lugs 51, disposed in engagement with the follower 47. The stem is recessed at its inner end to receive a roller 52 on the outer end of a lever 53 operable within a slot 54 formed by cutting away a portion of the plates 28 and 29 as shown in Figures '3 and 6. The lever is pivoted at 55 within the base plate 28 and a bearing block 56 which is connected therewith by screws 57 as shown in Figure 4. The lever is provided at its inner end with upper, lower and intermediate projecting portions 58, 59 and 60, respectively, which terminate in the arc of a circle, the center of which preferably coincides with the pivotal axis of the lever. One or the other of these projections is at all times disposed in the path of the pins 26 and 27 on the movable chair section13, so that if either of the pins is moved past the inner end of said lever it will engage one of the projections and shift the movable contact 36 to make or break the circuit as desired.

The spring housing 44 is provided at one side with three notches as indicated at 61, each of which is adapted to receive a ball 62, held in frictional engagement with the housing by a spring 63 disposed in a recess formed in the base plate 28 andsecured therein preferably by a screw plug 64 as shown in Figure 6. Thus means is provided for resisting movement of the housing 44;and the movable contact 36 carried thereby until a predetermined pressure has been built up in the spring Ell) ed and the consequent burning of the contacts prevented which would not be the case,

under slow movement of the parts. This is true regardless of the direction of movement of the operating stem 19 and lever 53 for moving the same.

The reversing switch includes a movable switch bar 65 having two upstanding contacts 66 at one end and three similar contacts 67 at the other end which are suitably insulated from the contacts 66. The fixed contact members, adapted for cooperation with the movable contacts 66 are indicated, two at 68 on one side of the movable contact and two at 69 on the opposite side thereof. The fixed contacts adapted for cooperation with the movable contacts 67 are indicated, three at 70 and the other three at 71 all being shown in Figure 1. The fixed contacts 69 and 71 are connected to the plugs 1 to inclusive while the fixed contacts 68 and 70 are connected to the plugs 6 to inclusive. Movement'of the switch bar to the right or left is adapted to be effected preferably by movement of the pedal 14 to the right or left as may be required depending upon whether it is desired to have the motor raise or lower the chair sections. The operating means between the pedal and movable bar 65 is not shown, but is preferably the same as that disclosed in my co-pending application referred to above.

The fixed contacts 39 and 41 of the limit switch are connected to plugs 5 and 10 of the reversing switch by wires 39 and 11 respectively as shown in Figure 1. Thewires 39 and 41 are adapted in conjunction with the wire 40 to complete the motor circuit when the starting or reversing switch is moved to closed position. x

As indicated in Figure 1 certain of the sockets at one side of the switch are shown connected with certain of those at the opposite side, it beingunderstood that the arrangement is such as to afford reversal of the motor from either operating position, regardless of whether an A. C. or D. 0. motor is employed. With the wiring arrangement shown the several circuits can be easily traced for the two types of motors with the switch in either closing position. In this connection it will be understood that the limit switch 16 is included in the circuit and that with the latter in central position as indicated in Figure 7 the motor will become operative upon moving the starting switch to elther of its .closing positions regardless of the type of motor used. However, with the limit switch in the position indicated in Figures 1 and 8 the circuit through the main or starting switch can only be closed with the movable contacts of the latter adjusted to engage the fixed contacts 69 and 71, the plugs 1 to 5 of which take into a series of correspondingly arranged sockets formed in the right side of the switch plate 25, while the opposite plugs 6 to 10 inclusive take into a set of correspondingly arranged sockets formed in the left side of said plate. With the limit switch in the extreme reverse position from that shown in Figures 1 and 8 the circuit willbe closed and the motor reversed when the movable contacts of the main switch engage the fixed contacts 68 and 7 O. In the first named position of the switches the motor will operate to raise the chair while in the last named position it will operate to lower the same.

In the operation of the chair, assuming it is desired to raise it from its lowest position as indicated by the movable section 13 in Figure 8, the right side of the pedal as viewed in Figure 2 is depressed by the operator. This operation shifts the movable contacts 66 and 67 to the right as viewed in Figure 1 and into engagement with the fixed contacts 69 and T1 and closes the motor circuit through plugs 1, 2, 8, 7, 3, 4c and 5, either for the A. C. or C. motor, when it is desired to raise the chair. The motor is thus started and the lifting mechanism placed in operation, it being understood that the limit switch at this time will be in the position indicated in Figures 1 and 8. As the chair section 13 is" moved up the pin 26 will engage theprojection 58 of the lever 53 and move the switch to the positionshown in Figure 7 without breaking the circuit. The operator retains his foot upon thepedal until the chair is raised to the height desired and immediately upon release of the pedal the motor circuit is broken by return of the main switch to normal inoperative position through the action or" the pedal operating spring, not shown.

In the operation just described, should the chair sections be raised to substantially their maximum height, the motor circuit will be Figure 7 when the pedal is moved to the left to reverse the motor for the purpose of lowering the chair, it being understood that the return of the limit switch to its intermediate position does not break the circuit. which is now closed through the plugs 1, 6, 7, 8, 9 and 10. With the chair section 13 in the position shown in Figure 7, the projection 60 of the lever 53 is in position to be engaged by either of the pins 26 or 27 and it will be operated by one or the other thereof, depending upon the direction and extent of movement of the section from the position shown in said figure. The switch in this figure is in a position common to both circuits so that should the operator depress the pedal either to the right or left, the motor will be started.

lVhat I claim as my invention is 1. An electric switch comprising a support having three fixed contacts thereon, a holder reciprocab'ly mounted upon the support having a contact adapted for engagement with said fixed contacts and arranged to have three circuit closing positions, in one of which it engages all of the fixed contacts and in any position of which itengages two of said fixed contacts, spring-pressed means adapted to resist movement of the holder to and from its different positions, and yieldable operating means formoving the holder in opposite directions adapted to overcome the resistance of said spring-pressed means whereby to afford a relatively quick movement of the holder to and from each of its operating positions.

2. An electric switch comprising a support having three fixed contacts thereon, a holder reciprocably mounted upon the support and provided with a contact adapted to have three circuit closing positions, in one of which it engages all of the fixed contacts, springpressed means adapted to resist movement of the holder to and from its different positions, yieldable actuating means for moving the holder in opposite-directions adapted to overcome the resistance of said spring pressed means whereby to aiford a relatively quick movement of the holder from any of its several operating positions, and a lever connected with said actuating means and having three operating portions corresponding to the three positions of the switch, each of said portions being adaptedin said different switch positions to occupy substantially a common control position from which the lever is operable back and forth between its limits of movement; V

3. An electric switch comprising a support having three fixed contacts thereon, a holder reciprocally mountedupon the support and provided with a contact adapted to have three circuit closing positions, in one of which it engages all of said fixed contacts, actuating means for said movable contact adapted in each of its operations to effect a relatively quick movement thereof from one position to another, and a member operatively associated with said actuating means and having three operating portions corresponding to the three positions of the switch and adapted for movement in a circular path to a common operating point from which said member is operable to its different circuit controlling positions.

4. An electric switch comprising a support, a plurality of fixed contacts on the support, a guide upon the support, a holder slidable upon the guide, a contact movable with the holder to different circuit control positions with respect to said fixed contacts, and an actuating member for said holder having spaced operating portions arranged to occupy a common point in a predetermined V path upon movement of the actuating member between predetermined limits.

5. An electric switch comprising a support, a plurality of fixed contacts thereon, a holder reciprocally mounted upon the support, a contact movable therewith to different circuit control positions with respect to said fixed contacts, an actuating member for said holder having spaced operating portions arranged to occupy a common point in a predetermined path when the actuating member is moved back and forth etween predetermined limits, yieldable means for resisting back and forth movement of said holder, and spring means arranged to impart a relatively quick movement of the holder to its different control positions subsequent to a predetermined resistance to the movement thereof by said yieldable means.

6. An electric switch for controlling separate electric circuits comprising a support, three fixed contacts carried by the support, a holder reciprocally mounted on the support, acontact carried by and movable with the holder, said holder having an intermediate position in which its contact engages all of said fixed contacts and in which position the movable contact is effective to close either circuit,'said holder being movable inv opposite direct-ions from said intermediate position to effect independent closing of said separate circuits.

7. An electric switch for controlling separate electric circuits comprising a support, three fixed contacts carried by the support, a holder reciprocally mounted on the support, a contact carried by and movable with the h'older, said holder having an intermediate position in which its contact engages all of said fixed contacts and in which position the movable contact is effective to close either circuit, said holder being movable in opposite directions from said intermediate position to eifect independent closing of said separate circuits, spring pressed means arranged to resist movement of the holder to and from each of its circuit closing positions, and yieldable actuating means for moving the holder in opposite directions arranged to overcomethe resistance of said spring pressed means, whereby to afford a relatively quick movement ofthe holder to arate electric circuits comprising a support, three fixed contacts carried by the support, a holder reciprocally mounted on the support, a contact carried by and movable with the holder, said holder having an intermediate position in which its contact engages all of said fixed contacts and in which position the movable contact is efiective to close either circuit, said holder being movable in opposite directions from said intermediate position to effect independent closing of said separate circuits, and an operating member for said holder pivotally connected therewith having spaced actuating portions corresponding to each circuit closing position of the movable contact.

9. An electric switch for operation by a control device movable back and forth in a predetermined path, said switch comprising three spaced contacts one intermediate the other two and a movable contact adapted in one circuit closing position to engage all of said contacts and arranged in each of two other circuit closing positions to engage said intermediate contact and one of the other of said spaced contacts, and operating means for said movable contact having three different control positions corresponding to the three positions of said movable contact, said operating means extending in the path of said control device for movement thereby from each of said control positions to a different control position.

10. An electric switch for operation by a control device movable back and forth in a predetermined path, said switch comprising three spaced contacts one intermediate the other two and a movable contact adapted in one circuit closing position to engage all of said contacts and arranged in each of two other circuit closing positions to engage said intermediate contact and one of the other of said spaced contacts, and an operating device for said movable contact having three spaced portions each of which is adapted to be engaged by the control device when moving in opposite directions whereby to shift the movable contact to one of its circuit closing positions.

11. An electric switch for operation by a control device movable back and forth in a predetermined path and having a pair of spaced actuating members for the switch, said switch comprising relatively movable cooperating switch parts for controlling different circuits and an operating device for effecting relative movement of said parts having three spaced portions, one of which is adapted to be engaged for operation by both of said actuating members in the back and forth movement thereof and said other portions being arranged for engagement and operation each individually by one only of said spaced actuating members.

ADAM J. MAY.

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