US2437037A - Delayed action electric switch - Google Patents

Description

March 2, 1948.

P. A. NELSON EI'AL DELAYED ACTION ELECTRIC SWITCH Filed April 12, 1946 F -E- n H IN V EN TORS Per/e A. Nelson Patented Mar. 2, 1948 OFFICE DELAYED ACTION ELECTRIC SWITCH Pcrlcy A. Nelson and William R. Nelson, El Segundo, Calif.

Application April 12, 1948, Serial No. 861,548

4 Claims. (01. 200-34) manufacture, easy to install and being very reliable in operation.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanylug drawing. wherein:

Figure 1 is a cross-sectional view of a switch device constructed in accordance with the present invention.

Figure 2 is a view similar to Figure 1 but showing the switch device set in opening position but at the beginning of its opening cycle.

Figure 3 is a view similar to Figure 2 but show ing the switch at the end of its opening cycle,

Figure 4 is a fragmentary cross-sectional detail view taken on line 4-4 of Figure 3.

It is frequently desired to obtain a delayed action in opening a switch, as where house lights are to be extinguished when an occupant leaves the house, lighting being required for his egress, extinguishing the lights in one room in order to go to another room, and the like. This invention aims to provide a switch structure for accomplishing the above delayed action.

Referring to the drawing, II designates a housing for the switch mechanism. Pivotally mounted in housing II and having an actuating handle I2 projecting through a slot l3 in the top wall of the housing is a rockable member I4 of insulating material. Member I4 is formed with an internal bore IS in which is slidably mounted a rod element I6 biased to an extended position by a strong coil spring I1 contained in bore I5. Pivotally mounted in housing I l below and adjacent to rockable member I4 is a lever member I8 arranged to be contacted on its upper surface by a rod element I6. A stop lug I9 formed on lever member I8 is abutted by rod member IS in the position of the parts shown in Figure 1. When rockable member I4 is rotated counterclockwise to the position thereof shown in Figures 2 and 3, spring I1 exerts a force on the rod member I6 which tends to urge lever member I8 to Slidably mounted in one end portion of lever member I8 is a headed contact member I9 having a contact ball 20 formed on its lower end. Ball 20 is adapted to be resiliently received between a pair of spring contacts 2|, 2| connected in series with the external circuit. A spring 22 encircles the shaft portion of contact member I9 and bears between its head and the adjacent surface of lever member l8. When lever member I 8 is in its counter-clockwise rotated position, shown in Figure 1, contacts 2|, 2| are bridged by ball 20 and the external circuit is closed. A coiled spring 23 bearing between the bottom surface of lever member I8 and the lower wall of housing Il biases the lever member It to its circult-closing position.

Depending from the up er wall of housing II and formed with a vertical slot 24 through which the adjacent end of lever member i8 projects is a sleeve 25. Slidably contained in sleeve 25 is a second sleeve 26 which is carried by a collapsible rubber cylinder 21 positioned in the lower porits clockwise rotated position, shown in Figure 3. 56

tion of housing II. Sleeve 26 is secured to cylinder 21 by a throat member28 having a rubber valve seat 29 provided therein. cooperatively arranged with respect to seat 29 is a valve plug 30 which is pivotally engaged with and supported by the adjacent end of lever member l8. Plug 30 is formed with a vent port to prevent air pressure from being built up between the plug and the walls of sleeve 28.

A bleeder valve 3| is provided in the bottom of cylinder 21, said bleeder valve having an orifice 32 controlled in size by a needle valve screw 34 from below the bottom wall of housing II. Screw 34 is formed with a restricted vent 35 through which air may escape from cylinder 21 to the atmosphere. A spring 36 bears between the head of screw 34 and the lower surface of housing II to provide a frictional binding force on the screw to maintain its adjustment.

When rockable member I4 is rotated from its position shown in Figure 1 to its position shown in Figure 2, lever member I8 is rotated causing plug 30 to seat on throat seat 29, thereby trapping the air contained in rubber cylinder 21. Ball 20 remains in bridging position between contacts 2|, 2| but spring 22 is compressed. As air escapes from cylinder 21 through bleeder valve 3| under the pressure exerted on the rubber cylinder by spring I1, acting through rod member I6, lever member 18 and plug 30, the rubber cylinder collapses. As spring I1 expands, causing lever member I8 to be rotated further in a clockwise direction, the pressure of spring 22 builds 3 up to a point s'uflicient to disengage ball 20 from contacts 2|, 2|, thereby rapidly opening the external circuit. Figure 3 shows the switch in final open-circuit position.

By adjusting bleeder screw 34, the time delay in opening the circuit may be set to any desired amount, ranging from almost instantaneous ac-- tion to as much as ten minutes delay. y

when rockable member I4 is restored to its closed circuit position, shown in Figure 1, spring 23 raises plug ll from seat 29 and causes lever member II to quickly rotate counterclockwise to engage ball 29 between contacts 2|, 2| closing the external circuit. Rubber cylinder 21 resumes its normal distended position and the other switch elements assume their positions as shown in Figure 1. The switch is therefore quick acting in closing the external circuit but slow acting in opening said circuit.

If desired, the quick-release structure comprising the movable contact member l9' and release spring 22 may be eliminated and the movable contact member may instead be rigidly secured to the lever member l8 in the manner employed in a conventional type of switch. Under these conditions valve plug 30 would be normally substantially seated on throat seat 29 when the switch contacts are closed. Lever member i8 is sufliciently resilient to prevent the contacts from opening immediately subsequent to the rotation of handle [2 from switch-closing position to switch-opening position, and the opening of the contacts would be delayed until a substantial quantity of air has escaped from rubber cylinder 21.

Although a specific embodiment of a retarded opening electrical switch structure has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no lim itations be placed on the invention other than as defined by the scope of the appended claims.

What is claimed is:

'1. In an electric switch, a movable contact arm, a spring biasing said contact arm to a first position, a rockable resilient member engaging said contact arm, said rockable member being formed and arranged to exert a force at times urging said arm towards a second position, a normally open collapsible air container in the path of said arm as it moves toward said second position, means carried by said arm formed and arranged to substantially close said container as the arm begins its movementv toward said second position, and a restricted exhaust opening in said container through which air is expelled under the influence of said force as said arm continues its movement toward its second position.

2. In an electric switch, a movable contact arm, a spring biasing said arm towards its contact- I of the latter element.

closing position, a. rockable resilient member engaging said arm, said rockable member being formed and arranged to exert a force at times urging said arm towards its contact-opening position. a normally open collapsible air container in the path of said arm as it moves towards its contact-opening position, a plug connected to said arm and arranged to substantially close said container responsive to theinitiation of the movement of said arm towards its contact-opening position, and an adjustable exhaust orifice in said container through which air is expelled under the influence of said force as said arm continues its movement toward its contact-opening position.

3. In an electric switch, a movable contact arm, means biasing said arm toward its contact-closing position, a rockable resilient member engaging said arm, said rockable member being formed and arranged to exert a force at times urging said arm toward its contact-opening position, a deformable element in the path of movement of said contact arm toward its contact-opening position, and means carried by said arm and engageable with said deformable. element to substantially completely compress the latter responsive to the initiation of the movement of the arm towards its contact-opening position.

4. In an electric switch, a movable contact arm,

means biasing said arm toward its contact-closing position, a rockable resilient member engaging said am, said rockable member being formed and arranged to exert a force at times urging said arm toward its contact-opening position, a deformable element in the path of movement of said contact arm toward its contact-opening position, means carried by said arm and engageable with said deformable element to substantially completely compress the latter responsive to the initiation of the movement of the arm toward its contact-opening position, and a. restricted orifice in said deformable element through which entrained air is expelled during the compression PERLEY A. NELSON.

WILLIAM R. NELSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,812,914 Williams et al July '7, 1931 1,942,040 Wolfi Jan. 2, 1934 2,111,385 Boothroyd Mar. 15, 1938 2,329,104 Chirelstein Sept. 7, 1943 FOREIGN PATENTS Number Country Date 640,009 Germany Dec. 21, 1936

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