US2345023A - Pressure switch - Google Patents

Description

Mud! 1944- T. H. rARBRouGH ETAL, 2,345,023

PRESSURE SWITCH Filed Sept. 14. 1942 Zhwwvioms momasyarb r00 flea g; I

@Z/m '4 W Patented Mar. 28, 1944 UNITED STATES PATENT OFFICE raassm swrron Thomas H. Yarbrough and John Paul Wheat, Waco, Tex.

Application September 14, iua semi No. 45am (Cl. zoo-as) 1 Claim.

when the lubricant pressure is not in suiilcient I amount.

Another object of this invention is the provision of a device of the above-named character which may be easily and quickly adapted to an .engine and its ignition system, whereby the latfor will be broken should the lubricant pressure failfrom some cause and is of a construction to permit the device to be conveniently adiusted for operation on an engine having a battery ignition system. v With'these and other objects in view as will become more apparent as the description proceeds.

the invention consists of such novel features of construction, combination and arrangement of 1 parts as will be hereinafter more fully described and claimed.

For-a complete understanding of our invention, reference is to be had to the fol owing description and accompanying drawing, n which Figure 1 is a vertical sectional view'illustrating I a pressureswitch constructed in accordance with our invention.

Fig. 2 is a sectional view taken on the line 2-2 Fig. 3 is a diagrammatical view illustrating a wiring diagram showing the present invention cluding a base 6 on which is clamped or clinched a casing I. A diaphragm 8. is located within the casing i and is held in position onthe base I to form a pressure chamber 9 by the clinching of the casing 5 on the base. A threaded nipple II is integral with the base 5 and is equipped with a bore I I extending from end to end thereof and connecting with the pressure chamber 2. The nipple I0 is employed for connecting the pressure switch I into a lubricant pressure line or an internal combustion engine so that the pressure of the lubricant within the engine will act on the diaphragm for the purpose of flexing or expanding said diaphragm. As soon as the pressure falls below a predetermined amount or fails the diaphragm returns to its initial position.

A supporting member I2 is secured on the interior of the casing 1 in any well known manner It arranged a selected distance from the diaphragm. The contact member I adjacent its free end and upon opposite faces thereof is provided with contact points I! and ii. A pin I1 is secured to the contact member I and is engaged by the diaphragm so that when said diaphragm is expanded or flexed by the pressure of lubricant within the pressure chamber 2 the contact member is caused to near or change from a normal position.

The stud bolt II also provides a mounting for.

a contact member II a portion of which par allels the contact member I4 and is spaced therefrom. The contact member It includes a hookshaped portion extending about and spaced from the free end of the contact member and has secured thereto contact points and 2| also an insulating member 22 disposed opposite to an adjusting screw 22. The adjusting screw 22 threads into a bracket 24 a portion ofvwhich clamps between the casing and diaphragm and thereby is held in a fixed position. The 'setscrew 22 includes a knurled head 28 positioned under an opening 22 provided in the casing I. The knurled head is provided with a kerf 21 to be engaged by a screw driver or the like arranged to establish an electrical connection therewith through the opening 22 so that the set screw or djusting screw may be rotated in either direction. A lea! spring 20 is secured to the bracket 24 and rides against the knurled head for retaining the set screw against accidental rotation. Also a coiled spring 29 may be arranged on the set screw and bears against the head thereof and the bracket to assist in retaining the set screw against accidental rotation. The purpose of the set screw is to adjust the hook-shaped portion I! of the contact member ll relative to the contact points on the contact member It so as to adapt the use of the pressure switch 5 to either an ignition system of the battery type or magneto type and which will be hereinafter more fully described.

An insulating block 30 is arranged between the contact members I and I! where they are mounted by the lug bolt II on the bracket I 2.

Also an insulating sleeve 2| is provided on the lug bolt ii to insulate the latter from the contact member II.

The lug bolt l8 secures on the contact memher I! a contact finger I2 which bears against a terminal 22 mounted on and insulated from vthe casing 7.

A suitable gasket 34 is provided in the casing to effect a seal'between the latter and the base 2 to prevent the switch from losing pressure from the pressure chamber 9.

In Fig. 3 we have illustrated a portion of a battery type ignition system for an internal- -combustion engine, the battery being indicated by the character 35 one terminal of which is connected to an electrical ground by a conductor 88. Th other terminal thereoi is connected to an ammeter 31 by a conductor 38. An ammeter 31 is connected to an electric relay 8! by a conductor 40. A terminal ll 01 the re lay it is connected to an ignition switch 42 by a conductor 43. The ignition switch 42 is electrically connected to the coil ll of the ignition system by a conductor 45. The coil 44 is connected to the usual distribution (not shown) by the lead It. A terminal 41 of the relay 39 has a conductor ill connected thereto and the latter is connected to the ground by a manually operated switch Bl. The present invention is electrically connected in the battery type ignitionsystem by having the terminal 33 connected to the conductor 50 by a conductor 52. It is to be understood that the pressure switch i by having its nipple i threaded into a lubricant pressure line oi the engine becomes electrically grounded in the ignition system of said engine.

The relay 3! includes posts II and N electrically connected to the terminals II and 41 and are insulated from each other.

An electro-magnet 55 is included in the con- 'struction of the relay and is electrically connected to the terminal 38 and also is electrically connected to the post 84 by a conductor 56. a spring influenced contact arm 51 is pivotally mounted on the post 54 and acts as an armature for the electro-magnet 55, and is adapted to be drawn in engagement with the post. 53 when the magnet 55 is energized, the spring of the contact arm acting to disengage said contact from the post 53 when the magnet 55 is deenergized. The posts 58 and 54 are capabio of conducting electricity. When the ignition switch It is closed electric current may flow from the \battery through the ammeter, termiml "and post I to the ground by way of the switch II when the latter is closed. As soon as the electro-magnet is energized the contact arm I! is drawn thereagainst-andmgainst the post II so that electric current may also flow through the ignition switch to the coil II.

In adapting the present invention to operate,

a position for sustaining the contact points It.

and il spaced from the contact elements..." and ii when the chamber 9 is free or pressure. This occurs when the engine is idle. When the engine is cranked or started the lubricant pressure is low or near zero and the switch ll must be closed as well as the ignition switehior the starting of the engine. However, as soon as the lubricant pressure reaches norm'al under the operation oi the engine, the diaphragm -exponds and moves the contact member "so that the contact point I! engages the contact point 2| connecting the conductor 80 to the ground through the present invention, the switch I is then manually open. When the device is operating as described, should the lubricant pressure cease from any cause, the diaphragm will return to its initial position permitting the contact element II to assume its normal position disengaging the contact points I! and 20 interrupting the electric circuit of the magnet 65 so that the latter becomes de-energized and the contact arm 51 under the influence of its spring then moves into the circuit breaking position. breaking the ignition circuit to the coil deenergizing the latter and consequently stoppinig the operation of the engine. This will preveni operation of the engine when the lubricant pressure fails and consequently prevents the engine from damaging itself from want or lubricant.

As shown in Fig. 2 the spring 28 has a biiurcated end to straddle and contact the knurled head of the adjusting screw for the purpose oi retaining the adjusting screw against accidental rotation. However, the adjusting screw may rotate relative to the bifurcated end when a screw driver is placed in the kerf and rotated.

It will be seen through the use of our invention in the battery type ignition system that ii the ignition switch 42 is left closed when the engine is idle, the battery will be prevented irom discharging owing to the iact that the pressure switch 5 is in circuit breaking position at this time owing to the fact that it is free of any lubricant pressure. Therefore the present invention provides for automatically stopping the engine should the lubricant pressure tail and also will prevent discharge of the battery when the engine is idle ii the ignition switch is left closed.

While we have shown and described the preferred embodiment of our invention, it will be understood that minor changes in the construction, combination, and arrangement of parts may be made without departing from the spirit and scope of the invention as claimed.

Having thus described our invention, what is claimed is:

In an automatic pressure switch for an ignition system of an internal combustion engine, a base. a diaphragm coacting with said base and providing a pressure chamber, a casing clamped to the base for securing the diaphrsgm to the latter, a threaded nipple formed on the base and connecting the chamber to I lubricant pressure system of an engine and electrically grounding the base to the engine, a contact member mountedin said casing and innuenced by said diaphragm, contact points arranged on opposite sides of the contact member, a second contact member mounted in the casing and insulated from the first contlci member and having a hook-shaped portion. contact points secured to said hook-shaped portion ior coacting with the contact points carried by the first-named contact member, a terminal carried by said casing and adapted to be connected into an ignition system of the engine a contact finger connecting said terminal to the second mentioned contact member, a brackat mounted in said casing, an adjusting screw carried by said bracket for the adjustment 0i thesecond-named contact member relative tc the first-named contact member, a spring member carried by the bracket and having a bii'urcated portion to engage the adjusting screw for sustaining the latter against accidental movement, said casing having an opening to permit a tool to extend therein to engage the adjusting screw.

THOMAS H. YARBROUGH.

JOHN PAUL WHEAT.

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