US3236963A - Pressure switch - Google Patents

Description

Feb. 22, 1966 E. A. PARMANN ETAL 3,236,963

PRESSURE SWITCH Filed Jan. 16, 1964 2 Sheets-Sheet 1 Feb- 22, 1966 E. A. PARMANN ETAL 3,235,953

PRESSURE SWITCH Filed Jan. 16, 1964 2 Sheets-Sheet 2 United States Patent O 3,236,963 PRESSURE SWITCH Edwin A. Parmann, Batavia, and .lohn Firth Marquis, St. Charles, Iii., assignors to Fnrnas Electric Company, Batavia, Ill., a corporation of Delaware Filed Jan. 16, 1964, Ser. No. 338,153 4 Claims. (Cl. 200-67) The invention relates to electric switches and has reference more particularly to pressure actuated switches of the toggle type for controlling and protecting electric motors when providing power for water pumps, air compressors and the like.

An object of the invention is to provide a toggle actuated pressure switch which will be simple in construction, embodying relatively few parts, which will be highly efficient in operation and which can be readily adjusted for contact closing at different pressure settings and also adjustable for varying the spread between the cut-in and cut-out pressures.

Another object of the invention is to provide a pressure switch of the toggle actuated type which will incorporate a lost motion connection between the snap acting toggle member and the contact strips to enable the toggle member to gain some momentum in an opening direction before the contact strips are engaged, whereby the initial opening action of the contact strips is fast enough to prevent arcing.

Another and more specific object of the invention resides in the provision of a connecting bar of insulating material which is disposed transversely for joining the spaced contact strips of the toggle switch mechanism and wherein a lost motion connection is provided between the toggle member and the said insulating bar.

Another object is to provide a pressure actuated lever for actuating the toggle mechanism and which will have a pivotal connecton with the bottom wall of the frame structure housing the switch mechanism.

With these and various other objects in view, the invention may consist of certain novel features of construction and operation, as will be more fully described and particularly pointed out in the specication, drawings and claims appended thereto.

In the drawings which illustrate an embodiment of the device and wherein like reference characters are used to designate like parts.

FIGURE l is a longitudinal sectional View, taken vertically through the pressure switch of the invention substantially alongline 1 1 of FIGURE 2, and showing the toggle mechanism in a closed contact position;

FIGURE 2 is a top plan view of the switch of FIGURE 1 taken substantially alongline 2 2 of FIGURE 1;

FIGURE 3 is an end elevational view looking at the right hand end o FIGURE 1;

FIGURE 4 is a bottom plan View substantially along line 4 4 of FIGURE 1 showing the toggle mechanism, and also the connecting bar of insulating material and the contact strips associated therewith;

FIGURE 5 is an end elevational View looking at the left hand end of FIGURE 1;

FIGURE 6 is a longitudinal sectional view similar to FIGURE 1, taken vertically through the switch but showing the toggle mechanism in an open position as regards the contacts;

FIGURE 7 is a detail sectional view taken substantially along line 7 7 of FIGURE 2 and showing the contact strip in circuit closed position;

FIGURE 8 is a detail sectional view similar to FIG- URE 7 but showing the contact strip in circuit open position; and

FIGURE 9 is an enlarged fragmentary sectional View showing the bracket and hinge structure for the toggle 3,236,963 Patented Felo. 22, 1965 member and for the toggle actuating lever, with the parts being positioned as shown in FIGURE 6.

The supporting frame and housing cover for the switch of the invention are respectively indicated bynumerals 10 and 11, and as best shown in FIGURES l, 2 and 3 the supportingframe 10 includes abottom wall 12 andupstanding side walls 13 and 1d. The housing cover 11 is removable as a unit from the frame to expose the switch, which essentially includes thecontact block 15 and the pressure actuatedlever 16.Projections 17 are formed on the contact block and said projections iit withinopenings 18 in theside walls 13 and 14 for releasably retaining the contact block in place.

Thenozzle 20 is suitably secured to thenozzle ange 22 and theresilient rubber diaphragm 21 is interposed between and sealed by the bottom wall and by thenozzle flange 22. The nozzle proper is internally threaded at 23 for securement to a source of pressure which actuates thediaphragm 21 and which in turn actuates thepressure lever 16. The said lever is pivoted at Z4, FIG-URE 1, to thebottom wall 12 and intermediate its length the lever has adepressed portion 25 which lies directly over and has contact with thediaphragm 21. The free end oflever 16 is held by thepower spring 26 which encircles thepower spring screw 27, the head of the screw being located below thebottom wall 12 and eX- tending through an opening therein to within thepower spring 26. Thepower spring 26 is thus coniined between the lever and thecompression adjusting member 23 which is threaded at the upper end of thescrew 27. By adjusting the position ofmember 23 onscrew 27 the compression force of thepower spring 26 can be varied and thus the switch mechanism can be adjusted to cut-out at different pressures.

The contact block 1.5 of insulating material carries the metal terminals 3i) and 31, FIGURES 2, 3 and 5, for the conductors to the line andsimilar terminals 32 and 33 are provided at the opposite end of the contact block for the motor line conductors. The terminals are bent around the respective ends of the block and the terminals are positioned between thecenter rib 34 and the side ilanges 35 forterminals 3G and 32, and between thecenter rib 34 and the side anges 36 for theterminals 31. and 33. A terminal screw such as 37 is provided for each terminal for fastening the conductors to the said elements. Theterminals 3@ and 31 have theiixed contacts 33 and di) suitably secured to their underside as shown in FIGURE 3. Theterminals 32 and 33 have thecopper contact strips 41 and 4t2; riveted at 39 to their underside and the said contact strips extend longitudinally so as to overlie the Xed contacts on the terminals 3i) and 31, respectively. At this end of the contact strips the same are provided with thecontacts 43 and d4, which, of course, have movement, due to the flexing of the contact strips, for coaction with theiiXed contacts 38 and 40.

FIGURES 7 and 8 clearly show the manner in which the terminals 3i), 31, 32 and 33 are bent around the respective ends of thecontact block 15. Said iigures also show the contact strips such as 41 and the manner in which lthe contact strips ileX for opening and closing the contacts of the present switch mechanism.

In accordance with the invention thecontact strips 41 and d2 are connected 4by thebar 45 of insulating material, the said bar being riveted at 45 to each of the strips. The inherent resiliency of the contact strips is such as to maintain themovable contacts 43 and 44 in engagement with thefixed contacts 38 and 40, respectively. Accordingly, in order to separate the contacts and disconnect the motor conductors from the power line, it is necessary to move the flexible contact strips in a downward direction. This is accomplished by means of a toggle member adapted to have snap action and which has a lost motion connection with thebar 45, all in a manner which will now be described.

Thenumeral 43 yindicates the toggle member which has -a pivotal intergaging connection at Sti with thebracket 51, FIGURE 9, the bracket being fixed to `the dependingpart 52 provided by thecontact block 15. Thetoggle member 48 is characterized by anarm 53 located approximately centrally of the member and which depends below the same and projects to` the left as shown in FIGURES 9 and 6. Thebar 45 is located between the arm and the toggle member, and it will be noted that the space occupied by the bar is greater than the thickness of the bar. This provides a lost motion connection between the parts.

The toggle actuatinglever 54, FIGURES 1, 6 and 9, also has a pivotal connection at 55 with thebracket 51 and which is located on approximately the same axis as that of the toggle member 4S. An opening is provided approximately centrally of the length of thelever 54 for receiving the bulbous nose of thepin 56. rThe base end of the pin is reduced in diameter and said reduced end is received in an opening in thepressure lever 16. Thus the pin operatively connects the pressure lever with the toggle actuating lever. Upward movement of thelever 16 will produce similar upward movement of thetoggle actuating lever 54. However, said upward movement of thelever 54 will take place against the compressive force of thecoil spring 57, which is contined between the top wall of the contact block and thetoggle actuating lever 54 at its connection with thepin 56.

The toggle mechanism is completed by the over-centerspring 58 and which is formed of resilient material having the shape of the letter C to provide the desired snap action for the elements of the toggle. The over-center spring 5S has a pivotal interconnecting engagement at 60 with the outer free end of thetoggle actuating lever 54 and said over-center spring has a similar pivotal connection at 61 With the outer free end of the `toggle member 48. The toggle elements normally assume the position shown in FIGURE l where the actuating lever 54 slants downwardly and thus the over-centerspring 55 yieldingly biases thetoggle member 48 into its upward position where the outer free end of the member engages .the top wall of the contact block. With the toggle member so located in its upward position, thebar 45 connecting thecontact strips 41 and 42 is engaged by thearm 53 and the contacts of the switch are caused to close -as shown in FIGURE 7. This position of the parts occurs when the pressure force acting on the undersurface of thediaphragm 21 is below that of the compression exerted by thecoil spring 26 and coilspring 62 on thepressure lever 16. r1`he action of the.arm 53 is such as to press on thebar 45 to hold the contacts in a closed circuit position.

When the pressure of the gas, water, or other liquids on thediaphragm 21 exceeds the hold down force of thecoil spring 26 andcoil spring 62, thelever 16 and thelever 54 are 4caused to pivot upwardly and lat a predetermined pressure level, or in other words, at approximately a horizontal positioning of thetoggle actuating lever 54, the over-centerspring 58 will produce a snap movement of thetoggle member 48 into its down position as shown in FIGURE 6. In said `down posit-ion of the toggle member the free end of the member engages a bottom wall of the contact block. The effect of this pivotal movement of the toggle member in a downward `direction is to cause thebar 45 to also move down and thus the contact strips are actuated to open the contacts of the switch as shown in FIGURE 8.

The lost motion connection between the toggle member and the connecting bar allows the opening action of the toggle member to gain some momentum before the bar is engaged and moved to open the contacts. As a result the initial opening action of the contacts is fast enough to prevent arcing.

That portion of the contact block indicated bynumeral 52 is cored to provide a bore or receiving thediierential spring 62, FIGURES 1 and 6. The differential pin 63 has contact with the lower end of the spring .and the compressive force of the spring can be adjusted by the threadedcap screw 64. The pin 63 has contact with thepressure lever 16 and thus thedifferential spring 62, and also themain spring 26 will force the lever down against the pressure of the gas or liquid on the underside of thediaphragm 21. The switch contacts are caused to open only when the pressures on thelever 16 reach a predetermined level suicient to elevate the lever the required amount against the compressive force of bothsprings 26 and 62. This is known as the cut-out pressure of the switch. By adjustment of thecap screw 64 the difference or spread between the cut-out pressure and the cut-in pressure for the present switch mechanism can be adjusted. Compressing thedifferential spring 62 affects both cut-out pressure and dilierential range of the switch. However, increased pressure on thedifferential spring 62 does not affect the cut-in operation of the switch.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will, of course, be Vapparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. In an electric switch of the toggle type, a contact` block of `insulating material having a pair of spaced terminal members at each end, the pair of terminal members at one end of the block each having a fixed contact, a metal contact strip secured to each spaced terminal member at the other end of the block and said contact strips extending longitudinally so as to overlie the fixed contacts respectively, a movable contact secured to each contact strip and adapted to have closing and opening action with its respective fixed contact, a contact bar of insulating material extending transversely of the contact block and being xed at each end to a contact strip, a toggle device for effecting movement of the contact bar for said closing and opening action of the movable contacts, said toggle device including a toggle actuating lever and a toggle member having an arm integral therewith and which provides a slot for receiving the contact bar, an overcenter spring disposed between and connecting the toggle actuating lever and the toggle member, a bracket carried by the contact block and providing a support on which the toggle actuating lever and the toggle member are pivotally mounted, and the said slot which receives the contact bar providing an opening of greater depth than the thickness of the bar to form a lost motion connection between the bar and the toggle member in both directions of movement of the member.

2. An electric switch of the toggle type as definedb claim 1, wherein the toggle actuating lever and the toggle member .are mounted on said support for pivotal movement on approximately the same transverse axis.

3. In an electric switch of the toggle type, `a frame providing a bottom wall, a .pressure actuated lever pivotally mounted at one end in the bottom wall, a power spring lin compression against the other end of the lever for yieldingly maintaining the lever in contact with the bottom Wall, `a contact block carried by the frame above the lever, a toggle device carried by the contact block on the underside thereof adjacent the lever, said toggle device including a toggle actuating lever pivotally supported at one end, a toggle member also pivotally supported at one end on approximately the same axis as the toggle actuating lever, an overcenter spring connecting the ends of the lever and member opposite their pivot ends, and a pin located between the toggle actuating lever `and the free end of the pressure actuated lever for positively transmitting movement of the pressure actuated lever in a contact opening direction to the toggle actuating lever.

4. In an electric switch of the .toggle type, a frame providing a bottom wall, a pressure actuated lever pivotably mounted at one end in the bottom wall, a power spring in compression against the other end of the lever, a cont-act block carried by the frame above `the lever, a toggle device provided by the contact block and located on the underside of `the block, said toggle device including a toggle actuating lever pivotally supported at one end, a toggle member also pivotally supported at one end on :approximately -the same axis as the toggle actuating lever, an overcenter spring connecting .the lever and member opposite their pivot ends, a pin located between and havling Contact with the pressure actuated lever and the toggle actuating lever for positively .transmitting upward movement of the pressure `actuated lever to 4t-he toggle actuating lever, la diierential spring carried and positioned by the contact block, means extending between the diiferential spring and the pressure actuated lever for transmitting the compressive force of said spring to the lever, `and means for adjusting the compressive force exerted by the spring.

References Cited by the Examiner UNITED STATES PATENTS 2,439,747 4/ 1948 Nelson 200-67 2,771,527 11/ 1956 Hausler 200-166 3,046,368 7/1962 Kaminky 200-83 References Cited hv the Applicant UNITED STATES PATENTS 2,773,144 12/1956 Immel et al. 2,782,277 2/ 1957 Immel. 2,892,050 6/ 1959 Fisher. 2,919,321 12/1959 Lung.

BERNARD A. GILHEANY, Primary Examiner. R. K. SHAEFER, Examinez'.

G, MAIER, Assistant Examiner.

Claims (1)

1. IN AN ELECTRIC SWITCH OF THE TOGGLE TYPE, A CONTACT BLOCK OF INSULATING MATERIAL HAVING A PAIR OF SPACED TERMINAL MEMBERS AT EACH END, THE PAIR OF TERMINAL MEMBERS AT ONE END OF THE BLOCK EACH HAVING A FIXED CONTACT, A METAL CONTACT STRIP SECURED TO EACH SPACED TERMINAL MEMBER AT THE OTHER END OF THE BLOCK AND SAID CONTACT STRIPS EXTENDING LONGITUDINALLY SO AS TO OVERLIE THE FIXED CONTACTS RESPECTIVELY, A MOVABLE CONTACT SECURED TO EACH CONTACT STRIP AND ADAPTED TO HAVE CLOSING AND OPENING ACTION WITH ITS RESPECTIVE FIXED CONTACT, A CONTACT BAR OF INSULATING MATERIAL EXTENDING TRANSVERSELY OF THE CONTACT BLOCK AND BEING FIXED AT EACH END TO A CONTACT STRIP, A TOGGLE DEVICE FOR EFFECTING MOVEMENT OF THE CONTACT BAR FOR SAID CLOSING AND OPENING ACTION OF THE MOVABLE CONTACTS, SAID TOGGLE DEVICE INCLUDING A TOGGLE ACTUATING LEVER AND A TOGGLE MEMBER HAVING AN ARM INTEGRAL THEREWITH AND WHICH PROVIDES A SLOT FOR RECEIVING THE CONTACT BAR, AN OVERCENTER SPRING DISPOSED BETWEEN AND CONNECTING THE TOGGLE ACTUATING LEVER AND THE TOGGLE MEMBER, A BRACKET CARRIED BY THE CONTACT BLOCK AND PROVIDING A SUPPORT ON WHICH THE TOGGLE ACTUATING LEVER AND THE TOGGLE MEMBER ARE PIVOTALLY MOUNTED, AND THE SAID SLOT WHICH RECEIVES THE CONTACT BAR PROVIDING AN OPENING OF GREATER DEPTH THAN THE THICKNESS OF THE BAR TO FORM A LOST MOTION CONNECTION BETWEEN THE BAR AND THE TOGGLE MEMBER IN BOTH DIRECTIONS OF MOVEMENT OF THE MEMBER.

Images