US1883786A - Push switch - Google Patents

Description

Oct. 18, 1932. H. c. HANSEN ET AL PUSH SWITCH Filed May 5, 1931 INVENTORS HANS CHRISTIAN HANSEN ALFRED JOHN BENNETT yel'afZ-Zarny' Patented oet. 1s, 1932 UNITED `STATES PATENT OFFICE HANS CHRISTIAN HANSEN, OF WEST HARTFORD, AND ALFRED JOHN-BENNETT, F

HARTFORD, CONNECTICUT, ASSIGNORS TO THE ARROW-HART & HEGEMAN ELEC- TRIC COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CONNECTICUT PUSH SWITCH Application. mea my 5, 1931. serial No. 535,224,

This invention relates to switches which are adapted to be operated by pressure -applied to a spring pressed plunger. More articularly the invention relates to a swltch 6 which is normally biased in'one position but which upon application of pressure snaps to another position and upon removal of that pressure returns to its original position.

The switch is particularly useful in control- 10 ling lighting circuits for illuminating closets,

iceboxes and the'like wherein it is desired to illuminate the interior upon o ening of the door and to extinguish the light y closing the door. However, the switch is not limited to .15 such use, but is applicable to use in many other situations.

It often happens in mounting switches of the above type that slight inaccuracies creep in whichwould permit-the door to impart 20 greater movement than necessary to the switch operating member. Unless provision is made to take care of inaccuracies in mounting and expansion and contraction of the members adj acent'the switch and upon which 25 it is mounted, the switch may become permanently damaged by excessive movement of the switch operating member.

Therefore, it is an object of this invention to provide a switch of the above type with 3 means to take up any excess movement of the door or other devicefor switch actuation, so that the switch mechanism will not be damaged by such excess movement.

Another object of .the invention is to pro vide a compact easily manufactured'substa-ntially built switch of the above type. Other objects and advantages of the invention will appear as it is described in connection with the accompanying drawing. In the draw- 1ng:-

Fig. 1 is an elevation view of the invention with the operating mechanism shown in midsection and the switch contacts in closed circuit position.

5 Fig. 2 is a view similar to Fig. 1 but with the switch in open circuit position.

Fig. 3 is a view similar to Fig. 1 but showing the switch parts in the position taken by them when they are given an excess movem ment by the door or other actuating device.

Fig. 4 is a sectional elevation view of the invention with the section taken on the line 4-4 of Fig. 1.

Fig. 5 is a detail view of the plunger.

Referring to the drawing the switch proper is of the type shown in the Guett Patent 1,511,809 patented October 14, 1924, in which a laminated insulating base contains suitable contacts 12 which are adapted to be bridged by an anti-friction roller 14 which moves in a switch cavity 15 in the insulating base. rThis roller is moved by a switching member 16, through the agency of a switch operating lever 18 as will hereinafter be more fully described. A metallic casing 2O embraces the insulating base and together with the rivets 22 confines the laminations of the base; There is an opening in the top of the metallic casing in which is secured an eX- ternally threaded sleeve 24 for mounting the switch in the desired location.

A hollow cylindrical plunger 26 is slidably received within the sleeve 24. This plunger has a.pair of diametrically opposed slots 27 formed in its lower end through which projects a spindle 28 mounted diametrically in the sleevek 24 and upon which is a pivotally mounted switch operating bell crank lever 18. One arm 18a of this lever engages in an aperture 29 in the bottom` part of the plunger,l thisaperture 29 being spaced midway around the plunger between the slots 27. The other arm 185 of the bell crank lever 18 `engages with the switching member 16 to cause movement. thereof in the manner described in the Guett Patent 1,511,809.

From the foregoing it will be apparent that if the plunger is moved up and down within the mounting sleeve'the arm 18a will be caused to rotate about the spindle 28 and hence will cause the arm 18?) to move and throw the switching member 16 from oil to on position and vice versa.

.The range of movement of the bell crank operating lever 18 is controlled by the following means.

The upward movement of the plunger is limited by the lower end of the slots 27 abutting the spindle 28 and also by arm 18?) abutting the inside of the sleeve 24. The 100 downward movement of the plunger is limited by the upper end of the slots 27 abutting the spindle and also by a shoulder 30 on the upper end of the plunger 26 abutting the top of the sleeve 24.

In order to prevent the spindle 28 from being deformed and also to protect the whole switch against injury by reason of excess pressure being put upon the plunger 26, we provide the following mechanism. An auxiliary coil spring 34 is placed within the plunger 26 with its lower end resting upon an inwardly directed shoulder 32 formed midway down the inside of the plunger. The upper end of this coil spring presses against a button 36 which is located in top of the plunger and is movable relative thereto. The lower part 36a of this button is enlarged and is of substantially the same diameter as the inside of the plunger.

In assembling the operating mechanism, the button 36 is placed within the plunger 24 with the auxiliary coil spring 34 under tension. Then the upper end of the plunger is turned over the enlarged lowerportion 36a of thebutton, thus sealing the button within the plunger with its small upper end 36?) projecting beyond the end of the: plunger.

It is desirable that the switch should be at all times biased to closed circuit position. For this purpose we provide a main coil spring 38 of less strength than the auxiliary spring 34 and having a smaller diameter than the auxiliary spring and working within the auxiliary spring. It is essential that both of these springs be of greater strength than the switch spring 168 as will hereinafter appear. The upper end of this main spring presses against the enlarged bottom of the button 36 while the lower end of the spring fits into a cylindrical cup 40 located in the bottom of the plunger, the diameter of the cup being approximately the same as the inside diameter oflthe lower end of the plunger. The bottom of the cup rests on the spindle 28 and therefore the cup is held against downward movement relative to the sleeve 24 as the main spring 38 is compressed when the plunger is depressed. In order thatthe bell crank lever may move freely a slot 42 is cut`in the bottom of the cup to permit the bell crank lever to rotate without engaging the bottom surface of the cup. However, this slot 42 serves to hold the bell I crank lever from axial movement along the spindle.

The operation of the device will now be described. llVhen` the switch is assembled the parts assume the position shown in Fig. 1. In this ligure the main spring pressing the cup 40 againstthe spindle 28v and pressing the button 36 against the overturned top of the plunger, causesthe plunger 24 to take its uppermost position. This causes the arm 186 of the switch operating lever 18 to take itsleft hand position. See Fig. 1. Now when pressure is exerted upon the button, the pressure is transmitted through the auxiliary spring to the plunger which is caused to de-v scend by reason of the strength of the auxiliary spring being greater than that of the spring of the switch mechanism. Depression of the plunger causes the bell crank lever 18l to rotate the arm 18?) of the lever eventually causing the switching member 16 to move to open circuit position as shown in Fig. 2. When the plunger has been depressed as far as possible the upper ends of the slots 27 abut the spindle 28 and the shoulder on the outside of the plunger rests upon the top of the mounting sleeve 24. Further depression of the plungerv is therefore impossible without damage to the switch.

However, due to inaccuracies in mounting the switch, or due to overthrow of the door or other object with which the plunger is cooperating, there may bea tendency to move the plunger further than is necessary to operate the switch. But, since the door presses against the button 36 and not against the plunger, the button may be moved further, Y

compressing the auxiliary spring and taking up the overthrow and thereby .saving the switch from damage. The position 'of the parts when this overthrow is taken u is shown in Fig. 3. Upon movement of the oor away from the button the parts assume the position of Fig. 1 by reason of the strength of the main spring 38 being great enou h to raise the plunger against the bias o the switch spring.

The switch is particularly useful in con# nection with a door, and in such a case would be mounted so that the closing of the door would depress the plunger and open the switch and opening of the door would release the plunger and allow the switch to be opened automatically bythe pressure of the main spring causing the plunger to rise. However, the switch is in no wise limited to this use but may be varied in innumerable ways to suit varieties of situations.

From the foregoing it will be seen that we have constructed' a compact switch operating mechanism for use with a conventional type of snap switch which will take up all overthrow which might normally occur due to expansion and contraction of parts cooperating with the switch or due to inaccuracy in mounting the switch.il Obviously the switch mechanism per se may be varied widely within the scope of the invention. Many changes in form will occur to those skilled in the art', therefore we do not limit ourselves to the specific embodiment of the switch shown herein.

1. An electric switch comprising a casing, a sleeve mounted on said casing, a plunger Blidably engaged with said sleeve, a spindle journalledin said sleeve and limiting the movement of said plunger, a button in said plunger and movable relatively thereto, main and auxiliary springs in said plunger constantly urging said plunger and button in one direction, and switch mechanism engaged and operated by said plunger.

2. An electric switch comprising a casing, a sleeve mounted on said casing, a plunger slidably engaged with said sleeve, aspindle journalled in said sleeve, and limiting the movement of said plunger, a button in said plunger and movable relatively thereto, main and auxiliary springs in said plunger constantly urging said plunger and button in one direction, a switch lever mounted on said spindle, and switch mechanism actuated by said lever as said plunger is moved.

8. An electric switch comprising a casing, a sleeve mounted on said casing, a plunger slidably engaged with said sleeve, a spindle j ournalled in said sleeve and passing through a slot in said plunger to limit the movement thereof, a button in said plunger and movable relatively thereto, main and auxiliary springs in said plunger pressing against said button and constantly urging said plunger and button in one direction, a switch lever mounted on said spindle, and switch mechanism actuated by said lever, as said plunger is moved.

In testimony whereof We have signed our names to this specification.

' HANS CHRISTIAN HANSEN.

ALFRED JOHN BENNETT.

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