US3200213A

US3200213A - Adjustable lever-actuated open-blade snap-action electrical switch

Info

Publication number: US3200213A
Application number: US296196A
Authority: US
Inventors: Jr Frank W Murphy
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-07-19
Filing date: 1963-07-19
Publication date: 1965-08-10
Anticipated expiration: 1982-08-10

Description

Aug. 10, 1955 F. w. MURPHY, JR 3,200,213

ADJUSTABLE LEVER-ACTUATED OPEN-BLADE SNAP-ACTION ELECTRICAL SWITCH Filed July 19, 1963 INVENTOR.

hired ADIUSTABLE LEVER-AQTUATED ()PEN-BLADE This application relates to a precision snap action switch, which is characterized by quick movement of the movable contact member from either open circuit to closed circuit position, or from one closed circuit to another closed circuit position.

Snap action switches are of course well known. However, none of the forms at presentknown have parts of suhicient rigidity for long lasting service in oil field work. The particular defect that militates against long lasting service is that the parts do not have adequate strength to mount contacts large enough to carry the heavy currents required in oil field work. It is also the case that the known snap action switches have their parts made of metals that are not corrosion resistant to hydrogen sulfide gas, which is commonly present in oil fields.

An object of the present invention is to provide a snap action switch in which the parts are made of rigid metal structural elements and the overall device is of sturdy construction.

Another object of the present invention is to provide a snap action switch having a unique adjusting means for the range of travel of the movable contact member.

A further object of the present invention is to provide a snap action switch having unique adjusting means for both the movable and the fixed contacts, the adjusting means for the fixed contact cooperating with the adjusting means for the movable contact to limit the travel of the latter from one circuit closing position, through dead center, to another circuit closing position.

Still other objects, advantages, and improvements will become apparent from the following specification, taken in connection with the accompanying drawing, in which:

FIGURE 1 is a side elevational view of the snap action switch according to the present invention;

FIGURE 2 is a top plan view with part of the operating lever broken away;

FIGURE 3 is a transverse vertical sectional view taken on the section line 3-3 of FIGURE 1 and looking in the direction of the arrows;

FIGURE 4 is also a transverse vertical sectional view taken on the section line 4-4 of FIGURE 1 and looking in the direction of the arrows; and

FIGURE 5 is a partial transverse vertical sectional view, taken on the section ilne 55 of FIGURE 1 and looking in the direction of the arrows.

Referring now to the drawing in detail and to FIGURE 1 in particular, the precision snap switch according to the present invention is mounted on a base Ill, which is preferably made of Bakelite, or one of the other well known phenolic condensation products. Three L-

shaped terminals

12, 13, and 14 have their

upper arms

12a, 13a, and 14a positioned below and transversely of the base and held in place by rivets 11, which extend through suitable holes in the base and aligned holes in the upper arm. These terminals have holes 15 therein adjacent the bottoms of their vertical arms for the reception of binding posts (not shown) to which the conductors (also not shown) from the associated circuit are attached.

The terminal 12 is the connection for the movable contact of the switch. An L-shaped bracket 16 has a flange 1611 at its bottom and is positioned longitudinally of the base It It is held in place by the same rivets 11 that hold the L-shaped bracket 12 on the underside of the base, these rivets assing though holes in the flange 16a which are aligned with the holes in the base and the holes in the 1 :1 Patent 0 arm 12a on the bracket. Below its mid-horizontal plane the bracket 16 has in its opposite edges slots 171'7. Along its longitudinal center line and on the opposite sides of its transverse center line the bracket is formed with an opening 18 having rounded ends, for a purpose that will appear hereinafter. Also along its longitudinal center line and extending from its top, the bracket is formed with a slot 19, which slot at its bottom merges with oppositely and transversely extending grooves mar-49a, likewise for a purpose that will appear hereinafter.

The movable contact member of the switch is a rectangular plate 20. At its rear end this plate is cut away along a rectangle 21, which has one side parallel to the end of the plate and which side is narrower than the width of the plate to form lugs 22-22 at the rear end. These lugs 22-22 are respectively received in the slots 17-17 in the sides of the bracket 16 to form a pivotal mounting for the contact member. From the transverse cutaway section 21 the contact member is also cut away at 23 along its longitudinal center line to a point beyond its transverse center line. Adjacent the front end of the longitudinal cut-away section 23 there is a hole 24 in the contact member, for a purpose that will appear hereinafter. A contact 25 is secured to the front end of the movable contact member 20 by a fiat headed screw 26.

An operating lever is generally designated by the reference numeral 28. It is comprised by a horizontal foot 28a, a lower leg section 28b inclined at an obtuse angle with respect to the foot 28a, and an upper leg section 280 merging with the lower leg section 2812 in a knee and inclined at a greater obtuse angle with respect to the foot 28a. The lower leg section 28a is formed with a large hole 30 along its transverse center line and a smaller hole 29 below the hole 30, for a purpose that will appear hereinafter. Immediately below the knee the lower leg section is formed with transversely extending slots 31-31 in its sides. The forward sides of these slots are formed by oppositely extending lugs 3232 at the knee. The upper leg section beyond these lugs is narrower than the lower leg section 2812.

The slot 19 and the oppositely extending grooves ISM-19a in the top of the bracket 16 form a selective dual pivotal mounting for the operating lever 28. As shown the narrower upper leg section 28b of the lever extends through the grooves Uri-4.9a in the bracket 16 and the oppositely extending lugs 3232 abut the bracket on one face. In order to shift the pivoted mounting of lever 28 it is merely necessary to turn the lever 28 horizontally in one direction to disengage one side thereof from its associated end of slot i or groove 19a until that side has engaged the other portion, and then turn the lever in the opposite direction, past the center line of the base to complete the shift from slot 19 to grooves 1%, or vice versa. After such shifting the lever is again centered with respect to the longitudinal axes of the base.

A coiled tension spring 27 has one end attached in the hole 24 in the movable contact member 20, is received in the longitudinal cutaway section 23 in the latter, extends through the elongated opening 18 in the bracket 16, and has its opposite end freely received in the larger hole 30 and attached in the smaller hole 2% in the lower leg section 28b of the operating lever. It will be apparent that 7 when the operating lever is in the last described position,

that is, with the slots 31-31 receiving the bracket 16 beyond the oppositely extending grooves Tim-19a in the latter, the spring 27 will be under greater tension than in the position of the operating lever shown when the lugs 32 32 on the latter abut one face of the bracket 16.

An adjustable rest stop is provided for the operating lever 28. A screw 33 extends through a suitable screw threaded hole in the base It? and has a lock nut 34 there on for abutting the underside of the base. The foot 38a of the operating lever abuts the screw 33, when the operating lever is in its rest position.

The terminal 13 is the connection for one fixed contact of the switch, this being the rest or back contact. A contact member 36 is of flattened or Z-shape. This contact member has a bottom flange 36a, which is positioned on the top side of the base 10. It is held in place by the same rivets 11 that hold the arm 13a of the terminal 13 on the underside of the base, these rivets passing through holes in the flange 36a, which are aligned with the holes in the base and the holes in the arm 1311. A fixed contact 35 is secured on the upper flange 36a of the contact member by a fiat head screw 26. The head of the screw 26 that holds the movable contact 25 onto the movable contact member Ztl rests on the fixed contact 35, when the operating lever 28 is in non-operated position.

An adjusting means is provided for the fixed contact 35. A screw 37 extends through a suitable screw threaded hole in the base it and has a lock nut 33 thereon for abutting the underside of the base. The upper end of this screw abuts the head of the screw 26, which holds the movable contact 35 onto the upper flange 36a of the contact member 36.

The terminal 14 is the connection for the fixed open circuit contact A bracket 41 has oppositely extending holes in the fiange 41b, which are aligned with the holes in the base and the holes in the arm. A fixed contact 40 is secured on the upper flange 41a by a frusto-conical head screw 39. The movable contact 25 abuts the fixed contact 40 when the lever 28 is operated.

As above stated, the base is made of Bakelite, or some other well known phenolic condensation product. The movable contact and the fluid contacts and are made of silver and gold plated to further increase conductivity. All parts, including the coiled tension spring 27, are made of Monel metal, so as to be highly resistant to the corrosive eifects of hydrogen sulfide gas which is commonly present in oil fields.

In operation, with the parts in the position shown, the axis of the coiled tension spring 27 is inclined at a lesser angle with respect to the horizontal than the plan of the movable contact member 20. Depression of the upper leg portion 28c of the operating lever will raise the right end of the spring 27 and shift the axis of the latter above the plane of the contact member 20. The spring 27 will then swing the contact member in the clockwise direction with snap action, the movable contact 25 abutting the fixed contact 4%. The switch will remain in this latter closed position as long as the upper leg section 280 of the lever is held depressed. When the latter is released, the spring 27 will swing the movable contact member 2% back to the rest position shown in FIGURE 1, also with snap action. In this position the movable contact 25 is on the first fixed contact 35. The angle of the upper leg section 280 of the operating lever in the rest position of the latter indicates the number of degrees that the operating lever 28 must be moved through in order to operate the switch. This can be changed by altering the setting of the stop screw 33. Also, the acute angle of the axis of the coiled tension spring 27 with respect to the plane of the movable contact member 2%) determines the degree of movement that must be imparted to the latter member before it will pass through dead center and complete its movement with the movable contact 25 abutting the normally open circuit fixed contact 40 in one direction of operation, or pass through dead center and complete its movement with the movable contact 25 abutting the v normally closed circuit contact 35 in the reverse direction of operation. As above stated, the tension of the coil spring 27 can be varied by changing the pivotal mounting of the operating lever 23 from the position shown, where the lugs 3232 on the lever abut the bracket 16, to the alternate position, where the slots Bil-31 receive the opposite faces of the bracket at the grooves 19a-19a.

I claim:

l. A snap switch comprised by a planar base, a rest contact mounted on said base, a bracket mounted on said base, a movable contact carrying member pivotally mounted at its rear end on said bracket and normally positioned at an acute angle with respect to said base, a movable contact on said movable contact carrying member positioned over the rest contact, a lever, plural pivot means carried by said lever selectively engageable with said bracket for varying the effective length of said lever relative to its pivot point and a coiled tension spring having its axis inclined at a lesser acute angle with respect to the base than the movable contact carrying member, one end connected to said member and the other end connected to said lever.

2. A snap switch comprised by a planar base, a rest contact mounted on said base, a bracket mounted on said base, a movable contact carrying member pivotally mounted at its rear end on said bracket and normally positioned at an acute angle with respect to said base, a movable contact on said movable contact carrying member positioned over the rest contact, a lever having one leg section inclined at an obtuse angle with respect to said base, a foot section on said leg section normally disposed parallel to the base, and another leg section united to the first leg section in a knee and inclined at a greater obtuse angle with respect to said base, pivotal mounting means at the knee of said lever securing same to said bracket, an adjustment means between the base and the foot section of the lever for varying the position of the latter with respect to the former, and a coiled tension spring having its axis inclined at a lesser acute angle with respect to the base than the movable contact carrying member, one end connected to said member and the other end connected to the first leg section of the lever.

3. A snap switch comprised by a planar base, a rest contact mounted on said base, an adjustment means between the base and the rest contact for varying the position of the latter with respect to the former, a movable contact carrying member pivotally mounted at its rear end on said bracket and normally positioned at an acute angle with respect to said base, a movable contact on said movable contact carrying member positioned over the rest contact, a lever having one leg section inclined at an obtuse angle with respect to said base, a foot section on i said leg section normally disposed parallel to the base, and

another leg section united to the first leg section in a knee and inclined at a greater obtuse angle with respect to said base, pivotal mounting means at the knee of said lever securing same to said bracket, an adjustment means between the base and the foot section of the lever for varying the position of the latter with respect to the former, and a coiled tension spring having its axis inclined at a lesser acute angle with respect to the base than the movable contact carrying member, one end connected to said member and the other end connected to the first leg section of the lever.

4. A snap switch comprised by a planar base, a first fixed contact mounted on said base, an adjustment means between the base and the first fixed contact for varying the position of the latter with respect to the former, a first bracket mounted on said base, a second fixed contact mounted on said first bracket in alignment with the first fixed contact, a second bracket mounted on said base, a

' movable contact carrying member pivotally mounted at its rear end on said second bracket, extending at its front end between said fixed contacts and normally positioned at an acute angle with respect to said base, a movable contact on said movable contact carrying member normally on the first fixed contact and movable onto the second fixed contact, a lever one leg section inclined at an obtuse angle with respect to said base, a foot section on said leg section normally disposed parallel to the base, an another leg section united to said first leg section in a knee and inclined at a greater obtuse angle with respect to said base, pivotal mounting means at the knee of said lever securing same to said second bracket, an adjustment means between the base and the foot section of the lever for varying the position of the latter with respect to the former, and a coiled tension spring having its axis inclined at a lesser acute angle with respect to the base than the movable contact carrying member, one end connected to said member and the other end connected to the first leg section of the lever.

References Cited by the Examiner UNITED STATES PATENTS 2,821,587 1/58 Cherry 200-67 2,958,744 11/60 Engle 200-l66 X 3,056,002 9/62 Ball 200-67 10 BERNARD A. GILI-IEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

Claims

1. A SNAP SWITCH COMPRISED BY A PLANAR BASE, A REST CONTACT MOUNTED ON SAID BASE, A BRACKET MOUNTED ON SAID BASE, A MOVABLE CONTACT CARRYING MEMBER PIVOTALLY MOUNTED AT ITS REAR END ON SAID BRACKET AND NORMALLY POSITIONED AT AN ACUTE ANGLE WITH RESPECT TO SAID BASE, A MOVABLE CONTACT ON SAID MOVABLE CONTACT CARRYING MEMBER POSITIONED OVER THE REST CONTACT, A LEVER, PLUAL PIVOT MEANS CARRIED BY SAID LEVER SELECTIVELY ENGAGEABLE WITH SAID BRACKET FOR VARYING THE EFFECTIVE LENGTH OF SAID LEVER RELATIVE TO ITS PIVOT POINT AND A COILED TENSION SPRING HAVING ITS AXIS INCLINED AT A LESSER ACUTE ANGLE WITH RESPECT TO THE BASE THAN THE MOVABLE CONTACT CARRYING MEMBER, ONE END CONNECTED TO SAID MEMBER AND THE OTHER END CONNECTED TO SAID LEVER.