US1903135A - Push button electric switch - Google Patents

Description

Patented Mar. 28, 1933 PATENT OFFICE MACKWORTH G. BEES, DETROIT, MICHIGAN PUSH BUTTON ELECTRIC SWITCH .Application :tiled February 6, 1930. Serial No. 426,283.

The present invention pertains to a no vel switch 4oi.: the push button type for controlling machinery or other electrical apparatus.

In the use of such switches forcontrolling machines in the industry, considerable trouble results from the entrance of particles of dust and dirt around the push button into the bodyv of the switch where it interferes with the working parts. The principal object of the invention is to provide a switch which obviates this dii'icult-y.

In the accomplishment of this object, the push button is snugly surrounded by a flexible gasket extending across the switch hous- 5 ing. The button is preferably formed with a head on the outward side of the gasket and surrounded by a spring which holds the gasket rmly against the head. l

Another object of the invention is to insure proper engagement between the relatively movable contacts of the switch when contact is desired. rlhe housing carries a pair of fixed 'contacts cngageable, by a movable contact mounted on the` push button. The movable contact is in the nature of a disk loosely mounted on the push button and placed under tension towards the fixed contacts by means of a spring. he looseness permits and the 3,) spring tension compels shitting of the loose contact to the relative position necessary for perfect engagement with the fixed contacts, and by virtue oi this construction the accurate setting or adjusting of the switch members in assembly is rendered unnecessary. y Furthermore, the spring limits the pressure that may be applied to the fixed contacts, so that the latter cannot be bent by excessive pressure on the push button.

example in the following description and in the accompanying drawing, in which- .Figure 1 is a bottom plan view of the device, with the lower gasket partly broken away;

Fig. ure 1;

Fig. 3 is a side elevation of the switch attached toa box or mounting which is illustrated in section;

2 is a section on kthe line 2-2 of Fig- The invention is fully disclosed by way of' Fig. 4 is a front elevation of the switch, corresponding to Figure 3; and

Fig. 5 is a section on the line 5-5 of Figure 4.

Reference to these views will now be made f' by use of like characters which are employed to designate corresponding parts throughout.

The device is built in a housing 1 of suitable insulating material which may be molded or otherwise formed as desired. The lateral wall 2 of the housing is\inclined outwardly and formed with a flange 3 depending from its upper edge. At the bottom of the housing is formed an integral boss or well 4 adjacent c5 which is a similar construction in the nature of a curved wall 5, for a purpose which will presently appear.

To the base or bottom of the housing 1 are attached two fixed contacts 6 and 7 which are 70 bent in such a manner as to extend over the lower end of the boss 4 as clearly shown in Figures 1, 2 and 3. These members are held against the bottom of the housing 1 by means of binding posts 8, the heads 9 of which are 75 molded in the bottom of the housing as shown in Figure 2. lThe member 7 has an extension l0 which enters the area enclosed by the curved wall 5 and there functions also as a contact for another switch unit as will presently appear. To the bottom of the housing is attached still another fixed contact member l1 by means of a binding post 12 and extending into the enclosure within the wall 5.

A push button 13 is slidably mounted in the 85 housing 1, through the bottom thereof, and is equipped with a head 14 at its upper end. The lower end l5 of the push button is reduced and extends into the well 4 where it is loosely 'surrounded by a movable contact 90 disk 16 adapted to engage the contacts 6 and 7 The shoulder formedbetween the body of the push button 13 and the reduced end l5 is engaged by a washer 17 surrounding the reduced end. The washer is in turn engaged by a conical coiled spring 18 surrounding the reduced end and bearing against l one side of the contact 16 which is held at its other side by a cotter pin 19 passed through the reduced end 15.

The housing is -completed by a cover 2O which fits over the fiange 3 and is suitably apertured at 21 to receive the head 14. A flexiblev 'gasket 22 for shielding the switch mechanism from dust and dirt has its edge clamped between the housing proper and the cover and snugly fits around the push button directly beneath the head 14 as clearly shown in Figure 2. The push button is also surrounded by a washer 23 inwardly of` the gasket and finally by another conical coiled spring 24 between the washer and the base 1 of the housing, whereby' to press the washer and gasket against the head 14 and normally move the button 13 outwardly. The cover is secured to the housing proper by screws 25 and nuts 26 as shown more clearlyl in Figure 5. Longer screws 27 are also passed through the cover and housing for securing the switch structure to a box 28 as illustrated in Figure 3. In this connection the gasket 29 is ap-v plied to the bottom of the housing 1 around the walls 4 and 5 and positioned to seal against the outer edge of the box 28 as also shown in Figure 3.

Another push button 30 generally similar to that described is slidably'mounted inthe housing 1 and cover 22 for coperation with the contacts 10 and 11. The reduced inner end .31 of this member may consist of met'al suitably attached'to the body portion cf the button which is preferably of a molded in.

sulating material. On the reduced end is loosely mounted a contact disk 32 adapted normally to bridge the contacts 10 and 11 as will presently appear. A spacer A33 is preferably fitted over the reduced end 31 between the disk and the molded body portion of the push button. The stem of the push button passes snugly through the gasket 22 directly beneath the button head 34 in the manner already described, and beneath the head is a washer 35 engaging the innerlside of the gasket. A conical coil' spring 36 surrounds Athe push button between the washer 35 and the base of the housing 1, thereby pressing the washer and gasket against the head 34 and holding the contact 32 in engagement with the fixed contacts 10 and 11 as illustrated.

The walls 4 and 5 serve as guards to prevent wiring within the box 28 from taking a position between the fixed and movable contacts Where it would interfere with the engagement of the contacts.

The dual switch illustrated is intended for y use in conjunction with a relay system, al-

though either of the units may be used separately forthe making and breaking of a circuit. In a relay system, however, the contacts 7 and 10 may be attached to a common conductor at their common binding post 8, while separate conductors may be attached to the remaining binding post 8 and the'post 12. The contacts 6 and 7 are normally spaced from each other, since the spring 24 tends "of the switch structure.

to retract the push button 13 and the movable contact 16 from the contacts 6 and 7 l The other movable Contact 32 however is in engagement with the fixed contacts 10 and 11 as already stated.

As an illustration of the use ofthe switch, the contacts 6 and 7 may be comprised in a circuit controlling a relay for making and breaking the circuit containing the contacts 10 and 11, the latter circuit also controlling a motor or machine. On compression of the push button 13 to bridge the contacts 6 and T, the first circuit is closed to operate the relay which closes the circuit of the contacts 10 and 11 of the machine. The button 13 may then be released to break the first circuit but vwithout interferin(Y with the second circuit. When it is desired to break the main circuit, the push button 30 is depressed to separate .the contact 32 from the contacts 10 and 11. Accordingly, the exposed heads 14 and 34 of the push buttons are labled Start and Stop respectively as Ashown in Figure 4.

Due to the loose mounting of the movable contacts 16 and 32 and .the spring tension thereon in the direction towards the fixed contacts, the movable contacts will at all times bear firmly against the fixed contacts, thereby removing the necessity of accurate setting, tting and aligning the various parts This tension is applied to the disk 16 by the spring 18 and vto the disk 32 by the spring 36. After engagement of the fixed contacts 6 and 7 by the adjacent movable Contact l16, continued depression' of the push button 13 results merely in a sliding movement of the button relativelyto the contact 16 surrounding it, the latter contact being held against the adjacent fixed contacts by the spring 18. It willA be evident that the spring mounting of the contact 16 prevents bending of the contacts 6 and 7 under excessive pressure on the push button 13.

rEhe several springs are so formed as to flatten oncompression, with the coils nested within each other. It is obvious that due to such construction, greater tension may be developed in a spring of given size than if the spring were merely cylindrical.

Although a specific embodiment'bfj the invention has been illustrated and described, it will be understood that various alterations in the details of construction may be made without departing from the scope of the invention, as indicated by the appended claims. "J

What I claim is:

1. In a switch, a housing having a bottom wall, a pair of fixed contacts carried by-said housing beneath said wall, a headed push button having a sliding fit in said housing and wall, a movable contact carried by said .button and adapted to engage said xed contacts, a asket snugly surrounding said push button etween said head and wall, a washer loosely surrounding said push button be neath said wall, a compressed spring surrounding said push button between said wall and gasket, another compressed spring surrounding said ush button between said movable contact an washer, whereby said sprin s press said gasket and washer respective y against said head and wall. v

2. In a switch, a housing having a bottom wall, a pair of fixed contacts carrled by said housing. beneath said wall, a head push button having a sliding fit in said housing and wall, a movable contact carried by said button and adapted to engage said Afixed contacts, a gasket snugly surrounding said push button between said head and wall, a washer loosely surrounding said push button beneath said wall, a compressed conical coiled spring surrounding said push button between said wall and gasket, another compressed conical coiled sprln surrounding said push but' ton between sai movable contact and washer, whereby said springs press saidgasket and washer respectivel against said head and wall, said springs ein adapted to be compressed into a substantially fiat condition. ,30 In .testimony whereof I aix my signature.

MACK'WORTH G. REEs.

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