US2653629A - Vacuum switch - Google Patents

Description

Sept. 29, 1953 F. w. HoTTr-:NROTH 2,653,629

VACUUM SWITCH Filed oct. 3o, 194e Frederid( M Hottenmth WYE/fm Patented Sept. 29, 1953 UNITED STATES PATENT OFFICE VACUUM SWITCH Application October 30, 1948, Serial No. 57,480

3 Claims. 1

This invention relates to a vacuum switch and particularly a diaphragm or bellows construction to be used in connection with a control switch, control valve or the like.

One object of the invention is to eliminate the necessity of having a relatively large diaphragm and a relatively large compression spring acting against it in order for the diaphragm to respond in a sensitive manner to pressure less than atmospheric.

Another object is to provide a diaphragm construction that can be readily mounted on a regulation pressure control switch in place of the usual pressure diaphragm and thus convert the pressure switch into a vacuum switch without the necessity of revising the switch action.

More particularly, it is my object to provide a vacuum responsive unit having a pair of diaphragms of different areas or equivalent means such as a pair of bellows, the vacuum connection being made to the space between the diaphragms.

A further object is to provide a diaphragm unit for response to vacuum in which the housing for the unit may be secured to a regulation pressure control switch or the like with connection to the space between the diaphragrns of the unit made at the outer end of the unit in the same position as the usual connection to a pressure diaphragm unit.

With these and other objects in View, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, wherein:

Figure l is a vertical sectional view through a vacuum switch embodying my invention and showing the parts in the switch-closed position as a result of a decrease in vacuum or increase in pressure, and

Figure 2 is a view of part '01" Figure l showing the switch in the open position as a result of an increase in vacuum or decrease in pressure.

On the accompanying drawing I have used the reference numeral IE to indicate a control switch housing having a cover ifi. rThe usual pressure operated control switch mechanism of the character shown in the copending application of Rothwell and Strasser, Serial No. 71,196, nled January 15, 1949, now Patent No. 2,562,437, issued July 3l, 1951, is contained in the housing I-IZ and comprises in general the following described mechanism.

A bracket I4 supports a knife edge pivot rod I6 against which a switch actuating lever I8 is engaged by a range spring 2i! adjustable by means of a screw 22. The switch arm IS carries a stud 24 for actuating a switch comprising an actuating spring blade 2B bent to normally assume the position of Figure l, and stationary and movable contacts 28 and 3.

The contact S is carried by a leaf spring blade 32 which is actuated by a blade 34 pivoted at one end to a bracket 35 and extending through an opening in an extension 3S of the switch blade 32. A spring extended toggle link 453 connects the blade 34 with a pointed element 42 on the actuating blade 25.

A diierential widening spring 44 is mounted on a screw 45 on the lower end of which a nut 48 is mounted. The nut 48 has an extension 5l! traveling in a slot 52 of a bracket 54 to prevent the nut from rotating when the screw 45 is adjusted for varying the tension of the spring 44.

An actuating pin 56 is slidable in a boss 53 of the housing and has a head 6i! on its lower end. When the foregoing described switch mechanism is operated as a pressure switch, a diaphragm housing is secured to the housing l@ as shown in the copending application above referred to and has a pressure responsive diaphragm engaging the head 6U. The pressure responsive switch may be converted to a vacuum responsive switch by means of my present invention comprising a diaphragm unit which will now be described, my unit being shown in heavy lines to distinguish it from the pressure switch mechanism thus far described.

I provide a diaphragm housing consisting of upper and lower formed plates 52 and secured together by screws Bit with a relatively large diaphragm 68 between them. This diaphragm separates the housing ft2-'S4 into two compartments designated lo and l2, respectively.

The plate 32 is secured to the housing i6 by means of screws 'i4 with a relatively small diameter diaphragm 'it interposed between the two. This seals on" the compartment "it from atmosphere, whereas uhe compartment 'i2 is open to atmosphere by means of a vent opening 13.

Between the diaphragms 53 and lli, I provide a formed spacer plate gli. rIhe compartment lil is the one in my diaphragm unit to be made responsive to vacuum and any type of connection may be made to this space but preferably I provide a ntting 82 mounted on the outer end of the diaphragm housing and connected with the space 'lll by a tube 84. The fitting is thus mounted in the usual position on the diaphragm housing so as to provide uniformity of installation for the vacuum switch the same as for the regulation pressure switch.

Practical operation In the operation of my vacuum control device, when the pressure is atmospheric or at least less than the desired vacuum at which cut out of the switch occurs, the range spring 20 will depress the diaphragms 68 and 76 as illustrated in Figure l thus permitting the spring blade 26 to close the switch contacts 2S and 30.

From the operation just described it is obvious l' that the switch is normally closed. The switch contacts may be connectedv with, a motor that operates a vacuum pump or "the likeva'nd they pump may evacuate a tank or other receptacle, the tank being hydraulically connectedwith the fitting 82 so that the diaphragm assembly responds to the vacuum created therein.' If this vacuum increases (or the pressure decreases .from

atmospheric) there will be an upward movement ofV the large diaphragm 68 in proportion tothe difference between its area and the Yarea of the diaphragm l5, the top of whichvis responsive to atmospheric pressure, and the bottomVo-f the dia`v phragm 68 being likewise responsive to at mospheric pressure. ,Y

When the vacuum reaches the desired pressure level for stopping the motor of the vacuum pump it will have raised the diaphragm 63 and subsequently the spacer Sil and the actuating pin 56 to swing the switch actuating arm IS as tothe 30 to the upper diaphragm which in turn movesv the actuating pin 5t for performing a control function such as operating the switch disclosed or avalve or any other control or indicating dev1ce.

The diaphragm assembly is so designed as vto respond to maximum vacuum without the necessity of providing the usual oversize single vacuum responsive diaphragm together with the necessary heavy range spring. My vacuum responsive'diaphragm unit can accordingly be substituted for a, pressure diaphragm unit on a regulation 'pres-` sure actuated control switch or valve without having to make any changes such as providing a heavier spring and reversing the switch action or valve action. From a manufacturing standpoint this is a substantial advantage and represents a considerable saving in manufacturing costs.V

While I have shown and described diaphragms 68 and '16, obviously a pair of bellows or equivalent means oan be used and the diaphragms may operate any type of control or indicating device without departing from the real spirit and purpose of my invention. It is, therefore, my intention to cover by my claims any modified forms of Ystructure or use of mechanical equivalents which mayv be reasonably included within their scope.

I claim as my invention: 1. In a vacuum actuated control device, a diaphragm housing having an opening, a large diaphragm mounted therein and separating said diaphragm housing into two chambers sealed by the diaphragm relative to each other, a small diaphragm mounted in lsaid opening and in sealing relation to the wall of said housing surrounding said opening, a vacuum connection to the space between said diaphragms, the small diaphragm being adapted to actuate a control element and responsiveon its outside surface to atmospheric pressure, said largerdiaphragm being responsive on its, outside surface to atmospheric pressure, and a spacer between said diaphragms comprising a disc against said large ydiaphragm and slightly smaller than it, said disc having a centrol embossed portion engaging saidsmall dia--v phragm and slightly smaller than it.

2. In a control device of the character disclosed, a diaphragm housing, large and small diaphragms mounted therein, the small diaphragmV being adapted for its outer surfaceto actuate a control element and responsive on the outside to atmospheric pressure, said large diaphragm being responsive on its outside tovatmospheric pressure, a spacer between said diaphragme, Yand* means for providing a vacuum'connection to the space between said diaphragms comprising a fitting mounted on the outer surface of said diaphragm housing opposite said Aouter surface oi said small diaphragm, and a hydraulic connection between said tting and said chamber.V f

3. `In a vacuum unit for connection toa control switch or the like, a small'diaphragm, a large diaphragm spaced therefrom, means for connecting the peripheries of said diaphragms to form a chamber between them, said small diaphragm being adapted to contact an actuating element for said control switch, a spacer between said diaphragms, a cover for said large diaphragm,` said cover and said means being connected together, said' cover having an opening to atmosphere, a'

tting mounted on said cover, anda hydraulic connection between said fitting and said chamber. n 'Y FREDERICK W. Ho-TTENROTH.'

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,510,475 Guenther Oct.,'7, 1924 2,421,284 Peterson May 27, 1947 2,435,716

Kearney Feb. l0, 1948

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