US2131264A

US2131264A - Vacuum actuated safety system for engines

Info

Publication number: US2131264A
Application number: US201081A
Authority: US
Inventors: Walter E Benjamin
Original assignee: PIERCE GOVERNOR Co
Current assignee: PIERCE GOVERNOR Co
Priority date: 1938-04-09
Filing date: 1938-04-09
Publication date: 1938-09-27
Anticipated expiration: 1955-09-27

Description

' Sept. 27, 193s. w. E. BENJAMIN V .2,131,264

VACUUM ACTUATED SA-FETY SYSTEM FOR ENGINES Filed April sa, 193s f -M`Tp11 Patented Sept. 27, 1 938 UNITED' STATES PATENT OFFICE VACUUM ACTUATED SAFETY SYSTEM FOR.

ENGINES corporation Application April 9, 1938, Serial No. 2Q1,081

13 Claims.

This invention relates to a safety device for internal combustion engines and more particularly for an engine provided with a governor, although not necessarily applied thereto.

5 The chief object of this invention is to prevent an engine from "running away beyond a safe speed which, if governor controlled, is above that speed for which the governor is set to function or maintain.

l The chief feature of the invention consists in providing a device in the form of a switch or its equivalent, in the ignition circuit of the engine which switch'is normally maintained in closed circuit condition until the engine runs away 15 and upon that attempt the switch is actuated to open the circuit and the same is maintained in open circuit relation until the switch is closed or the switching element is replaced, as will hereinafter be pointed out.

It will be apparent from the aforesaid that manual attention is required after switch operation for reconditioning the ignition circuit for subsequent engine operation. Therefore, the system is positive in its action from the standpoint of safety and maintenance.

The full nature of the invention will be understood from the accompanying drawing and the following description and claims.

In the drawing, Fig. 1 is a diagrammatic view B0 of one embodiment of the invention, parts being shown in the open circuit position.

Fig. 2 is a similar view of a modifiedfform of the invention.

In Fig. 1 of the drawing, I0 indicates a car- 35 buretor having a throttle or butterfly II therein and a venturi I2 in the discharge portion. I3 indicates an intake manifold portion of an engine. I5 indicates an opening in the carburetor discharge to the manifold between the valve or i0 throttle II and the venturi I2. I 6 indicates a conduit communicating at one end with the opening Il and at its opposite end having connection as at I1 with a vacuum operable structure, hereinafter tol be described in detail.

l5 For a vacuum operable device to properly function as intended, it is necessary the suction tube Il or rather the opening I5, be positioned between the carburetor venturi and the throttle or buttery valve, because the vacuum at this point is l0 dependent upon the velocity of the air stream passing through the venturi. The rise in vacuum at this point I5 will increase with the air stream velocity squared. Any movement of the valve I I from the wide openpositicn to another position,

such as shown dotted, will cause a drop in vac- (Cl. .12S-146.5)

uum at the point I5 and at the same time will cause a rapid rise in vacuum above the valve II or in the manifold I3.

It is evident, therefore, that when the engine is under governor control and the valve I I is actuated by the governor to control the motor speed, the rapid rise of manifold vacuum in the manifold, if connected to the vacuum operable device, would shut off the engine. If, however, the conduit I6, connected to the vacuum operable device, is connected as at I5 the vacuum operable device would not be effective during normal valve movement from the full closed position to a position almost wide open. It is only when the valve II is wide open, evidencing a governor failure or maximum speed under light load, that the suction is sufficient to operate the valve operable device. If the engine is under full load at wide open throttle, the speed of the engine will not be above the critical speed. Therefore, the velocity of the fuel supply through the venturi will not be that which is attained when the valve II is wider open and the engine is vunder little or lower load. Thus, for an engine which is governed in theevent of governor failure and the valve II becomes positioned as shown by the full lines in Fig. 1, the vacuum pull is such that it is effective for operating the vacuum device connected to the opposite end of the conduit I6. 'Ihis device is also effective in cases where an engine is not equipped with a governor and when for some reason or other the normal load is removed and the engine tries to run away.

Reference will now be had to one form of vacuum operable device which is shown in Fig. 1 35 and which furthermore is shown as of the diaphragm character although it is t0 be understood that the same, if desired, may be of cylinder and piston character without departing from `the disclosure. 40

I3 indicates a housing, I9 a complementary housing. The two form chambers 2li and 2i, respectively, which are separated from each other by the diaphragm 22 having the central metallic reenforced portions 23. The housing I3 is ex- 45 tended and includes a tubular portion 24 threaded as at 25 to receive a threaded member 23 internally threaded as at 21 to receive an adjusting bolt 23 having the head portion 29. The bolt 23 is locked in the adjusted position by the nut 33. The bolt 2S and portion 24 may,` if desired, be suitably secured in sealed relation as by the wire 3| and seal member 32. Breakage of this wire indicates tampering with the safety device.

The bolt 23 suitably mounts or abuts a spring 55 bearing plate 33 against which bears one end of a spring 54, the major portion or the spring being nested in the tubular portion tl of the housing member i9. The other end of the spring bears against the central reenforcement 53 of the diaphragm E2 in the chamber 2l. A nut 35 has threaded engagement with the stem 55 and bears against the face of the member 25 in the chamber ill. The threaded stem extends through the central aperture lll in the diaphragm and the aligned apertures 3b in the reenforcement plates t3. The nut 35 in the present instance, is shown nested within the spring 363.

A reciprocating member in the chamber 2@ provides a shoulder lll for the bearing against the reenforcing member 23 in the chamber Ztl. Herein the threaded extension 3&3 which passes through the apertures l'l and 32B, is an extension of the portion 59. supported in the bore ll in the housing i8 and is axially aligned with the spring and adjusting bolt, before mentioned.

Conduit l5, previously referred to, communicates as at [Il with the chamber 2l. The spring .ttl normally constrains the diaphragm to the right and, therefore, the plunger 39 is constrained to the right, the purpose therefor being set forth hereinafter.

When the suction or vacuum reaches the critical amount for which the device is set to operate as determined by the load imposed through the adjustment of bolt 25, and spring (it, the vacuum overcomes the spring pressure and moves the central portion of the diaphragm to the left, as shown in Fig. l, and holds the same in that position as long as this critical vacuum pull is imposed upon chamber 2l. When the vacuum imposed falls below the limit determined by the spring, et cetera, the diaphragm 22 through the spring tends toreturn to its original position which, however, is prevented in the present form of the invention.

The housing il@ includes an extension or bracket l2 and the same is of tubular character, forming the bore therein aligned with the bore il before mentioned. A lateral aperture till is provided near the free end of the bracket t2. Another lateral aperture l5 is provided immediately adjacent the opposite end.

Suitably secured as at [iii is an insulation member dll which supports a terminal stud i8 to which one wire i9 is connected. The stud also supports a spring member 55 terminating in a contact 5l. The member before mentioned, is elongated and mounts on its free end, the insulation member 52 normally contacted by the current carrying spring member 55. Mounted within the bore l5 at the extreme end of the bracket di. is the insulation member 53 and mounted therein is the stud 5d which constitutes another contact aligned with Contact 5l and in electrical connection with the line 55 as shown.

Suitably secured as at 55 and to the insulation member di is a spring structure 5l which extends toward the housing i8 and has its 'free end 58 nested in a slot 59 in a reciprocable member til, the same being slidably supported in -the aperture d5 and provided with the biased end 5l. The biased end 5l projects into the bore Mi. The slidable member 39 is grooved or channeled as at 52.

As shown, the member 55 projects upwardly a considerable distance and constitutes a manual engageable portion. In normal operation, the

The portion 3Q is slidably,

aisance the electrical circuit is completed through the wires 59 and 55. Thus, the ignition system is closed so far as the protective device is concerned.

Tn the event of governor failure or the like, as before set forth, and upon the application of sucient vacuum to the amount necessary to oppose spring and diaphragm tension, if any, the diaphragm ti! is moved to the left into the position shown in Fig. 1. This movement is permitted because at this time the member 6U is held elevated thereby for it rides on the portion and is held elevated in opposition to spring 5l. When the groove 52 registers with the member lill, spring 5l becomes effective and forces the plunger or catch downwardly as the device is herein illustrated, so that the biased end @i engages in the groove 52 of the member il@ and thus locks member 59 in the so-called retracted position, and when in that position and held in that position, the circuit through the contacts 5l and 5d is open and maintained in open circuit relation.

This catch prevents the return of the member 39 to the right which it would normally do were it not for the fact it is held by this catch. The reason for such return is as follows:

'When the ignition circuit is open and held open, the engine no longer operates a'nd gradually comes down in speed and thus the vacuum which is subjected to chamber 2l is reduced until the spring 3d would normally be eifective for returning the member 39 to its original closed circuit position. However, member 39 being locked in the so-called open circuit positioned diaphragm 22 and member 39 are prevented from so returning and, therefore, the circuit through lines 45 and 55 is maintained in open circuit relation. This is maintained until such time as the operator manually elevates the member 6D as illustrated herein, or in other words, retracts the catch 5l from the groove 62 whereupon spring 54 becomes effective, and since there no longer is sufficient vacuum pull in said chamber to hold the diaphragm in the position shown in Fig. l, the circuit is reestablished through members 5i and 5H.

lin View of the fact that an ignition system is illustrated in Fig. 2, the ignition system, including lines dit and 55, of Fig. l is intentionally omitted but it is to be understood that these two lines constitute an extension of a standard ignition system and operable by the primary supply line which is opened, one end being designated by the numeral M5 at the opening and the other end at the opening being designated by the numeral H55 in Fig. 2.

In Fig. 2 numerals of the 100 series indicate like or equivalent parts. The conduit l i6 is connected to the vacuum device in substantially the same manner as previously described and also to the fuel system of the engine substantially as previously described, and in substantially the same relationship with respect to the venturi and' butterfly valve, lit and iii, respectively.

The parts illustrated in the vacuum device to the left of the diaphragm |22, are substantially identical to that illustrated to the lei't of diaphragm 22 in Fig. 1.

When the diaphragm |22 is moved to the left as shown in Fig. 2 through the application of sufcient vacuum to the chamber |2| in opposition to spring |34 contact member |50 bridges contacts |82 and |80 and completes the circuit through lines |49 and |55 which accomplishes the result hereinafter to be specified. Immediately upon the engine attaining a lower speed by reason of the function of the system, as hereinafter pointed out, the diaphragm |22 moves to its median plane or adje/cent 'thereto under the influence of spring |34. When so actuated the bridging member |50 assumes the dotted line position. 'Ihis is the open circuit or normal position. This would immediately permit the engine to gain speed and endeavor to again run away.

Therefore, it will be noted the distinctions between the two iorms of the invention is that the one illustrated in Fig. 1 is oi' the mechanical lockout type whereas in Fig. 2 there is no mechanical lock-out. The lock-out, however, in this form of the invention is of the electrical character and one form of which is conventionally illustrated.

Under normal engine operation the circuit is from the battery |10 through the switch device |12, through the ignition switch |14 and by line |15 to the usual ignition circuit. Whenever the engine runs away, for example, member |39 moves the bridging contact |50 from the dotted line position to the full line position to complete the circuit between the lines |43 and |55. This creates a temporary short circuit which immediately is registered in the switch device 12, so that the latter opens the ignition circuit and maintains it open until it is manually actuated. Hence, after the engine has attained that lower speed where the spring |34 becomes operative upon the plunger and diaphragm ISS-|20, the circuit is held open between lines |55'and |49 but since the ignition circuit is now open between lines |1| and |13, no energy is supplied to line |15 so that the engine cannot again attain an excessive speed until the switch device |12 has. been actuated to close the ignition circuit.

Line |85 diagrammatically indicates a supply line from the battery to the starter of the engine. Line |86 diagrammatically indicates a supply line to the lighting system et cetera, of the motor vehicle in which the engine is mounted.

The switch device indicated generally by the numeral |12 is herein shown as a fuse |90. The short circuit breaks or burns out this fuse and requires the removal of the old fuse and the manual substitution of a new fuse. Thus, the engine is positively protected. While the fuse |90 is herein illustrated as the embodiment of the electrical switch which is of the character indicated, other switch means may be employed which have the same function, to-wit, upon a short circuit occurring as it were by means of lines |49 and |55 being electrically connected by the bridging contact |50, the switch |12 is automatically opened and is maintained open until it is manually closed.

Lines |49 and |55 indicate the application of` lines 49 and`55, respectively, to a standard ignition circuit as previously described.

It two carburetors are employed, two vacuum devices may be employed and in that event they may be as shown in Figs. 1 and 2 and connected electrically in the ignition .circuit as shown in Fig. 2. In this event dual protection is provided.

It thus will be apparent that both forms oi' the invention hereinbefore described and herein illustrated are vacuum operable devices for protecting an engine from running away and for imposing an open circuit condition upon the ignition system of the engine upon the engine attaining that critical speed ior which this vacuum operable device is adiusted to operate and having once effected such open circuit, the same is maintained until manual operation is employed to close the said open circuit.

While the invention has been illustrated and described in great detail in the drawing and foregoing description, the same is to be considered as illustrative and not restrictive in character.

The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claims.

The invention claimed is:

1. In a safety system for preventing running away of an internal combustion engine having an intake system with a control valve and Venturi means in juxtaposition thereto and provided with an ignition system, the combination of a vacuum operable device, van ignition circuit opening structure operable thereby, and means connecting the vacuum operable device to the intake system between the valve and Venturi means.

2. A system as defined by claim 1, characterized by the vacuum operable device including a load spring normally opposed to the vacuum operation, and means for adjusting the spring force.

3. A system as defined by claim 1, characterized by the vacuum operable device including a load spring normally opposed to the vacuum operation, means for adjusting the spring force, and means for sealing the adjusting means in the adjusted position.

4. A system as defined by claim 1, characterized by the ignition circuit opening structure in- ITS cluding a normally closed switch movable upon vacuum operable device operation to open circuit position and including latch means for retaining the switch in open circuit position upon device operation following vacuum operable de vice release upon engine acceleration.

5. l system as defined by claim l., characterized by the ignition circuit opening structure including a closed circuit maintaining short circuit operable arrangement, and switch means associated therewith and operable upon vacuum operable device operation to short circuit the arrangement for opening the ignition circuit.

i5. i system as defined by claim l, characterized by the ignition circuit opening structure including a closed circuit maintaining short ci"- cuit operable arrangement, and switch means associated therewith and operable upon vacuum operable device operation to short circiut the arrangement for opening the ignition. circuit, said arrangement being of fuse character.

il, A system as defined by claim l., characterby the ignition circuit opening structure inr ciuding a closed circuit maintaining short circuit operable arrangement, and switch rneans aseociated therewith and operable upon vacuum operable device operation to short circuit the ar for opening the ignition circuit, said being included series connection the ignition circuit and said switch means ben in multiple connection therewith.

S. A system as donned by claim l, characterm ined by the vacuum operable device being of diaphragm type.

0 A system Ias defined by claim i, charactenined by the vacuum operable device being ci diaphragm type, the ignition circuit opeg nic-ans and device operable connection including plunger secured at one end to the diaphragm, and load spring means opposing vacuum opera1 adorned tion of the diaphragm, said plunger localizing the spring means.

l0. A system as dened by claim l., characterized by the ignition circuit opening structure including a normally closed switch movable upon vacuum operable device operation to open circuit position and including latch means for retainn ing the switch in open circuit position upon device operation following vacuum operable device release upon engine acceleration, said vacuum operable device being of diaphragm type.

1i. A system as defined by claim i, characterized by the ignition circuit opening structure inw cluding a closed circuit maintaining short circuit' operable arrangement, and switch means associ ated therewith and operable upon vacuum operable device operation to short circuit the arrangernent for opening the ignition circuit, said vacuum operable device being oi diaphragm type.

l2. A system as dened by claim l, characterized by the ignition circuit opening structure in-- cluding a closed circuit maintaining short cirM cuit operable arrangement, and switch means associated therewith and operable upon vacuun operable device operation to short circuit the rangement for opening the ignition circuit, said arrangement being of use character, said vacuum operable device being of diaphragm type.

i3. A system as defined by claim l, characterd ized by the ignition circuit opening structure including a closed circuit maintaining short circuit operable arrangement, and switch means as sociated therewith and operable upon vacuuin operable device operation to short circuit the arrangement ior opening the ignition circuit, said L fill