US2243937A - Valve for bus door operating mechanisms - Google Patents

Description

June 3, 1941. J. R. ALMOND fwf/lfgygslus/DORJETING, MEcHANIsMs.

Filed Feb. l0, 1939 INVENTOR, Y y' dafiw E. Amo/D B254, M

ATTORNEY.

Patented June 3, 1941 FFHQE.

VALVE FOR BUS DOOR OPERATING MECHANIISMS J ohn R.. Almond, Cleveland, Ohio, assignor to The Midland Steel Products Company, Cleveland, Ohio, a corporation of Ohio Application February 10, 1939, Serial No. .255,713

Claims.

This invention relates to new and useful improvements in valve mechanism and an irnportant object of the invention is to provide one which can be selectively operated quickly with precision to eliminate the delays incident to hunting for valve positions.

More specifically, an object of the invention is toy provide quick acting valve controlling the supply and exhaust of motive iluid to and from opposite ends of an operating device by a reciprocable operating handle operated with snap action to quickly move and securely retain the valve in one or the other of its two extreme positions.

More specifically, an object is to substitute for the conventional single rotary valve subjected to rapid wear and deterioration through dust galling its sealing surfaces, a snap action poppet type valve which is` more rapidly and positively snapped into one or the other of its two positions by a reciprocable operating handle with a mere flick of the hand.

A further object of the invention is to provide a valve assembly embodying a pair of alternately opening poppet valves operated by means of snap action means, and which seal in both directions and are held against the pressure side of the valve so that they do not Hutter under air pressure or pressure build-up.

A further object of the invention is to provide an improved construction for the snap action mechanism to render it more fool-proof through long and severe service.

ther objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawing forming a part of the application and wherein like numerals are employed to designate like parts throughout the several views,

Fig. 1 is an elevation of the improved valve,

Fig. 2 is a longitudinal section of the valve,

Fig. 3 is a longitudinal section through the valve taken at right angles to Fig. 2,

Fig. 4 is a transverse section through the valve taken on the line 5--5 of Fig. 3,

Fig. 5 is a bottom plan view of the valve.

Heretofore, the front and rear doors of passenger busses have been operated by a vacuum or pressure medium controlled by a single rnotormans valve of the rotary type, having about five operating positions, usually a centra-1 neutral position in which both bus doors are closed, two extreme right and left positions in which both doors are opened or closed, and two positions intermediate the extreme and neutral positions in which one door is open while the other is closed. This type of single valve control requires precision of operation by the motorrnan for accurately controlling both doors so as not to injure passengers, especially because of the delicate intermediate positions of the valve which are so close to its other three positions as to require exact predetermined movements of the operating handle.

The invention herein disclosed provides for the selective operation of front and rear bus doors by means of two separate two position snap action valves, so arranged that the motorman can operate them substantially simultaneously with a single sweep or motion of the hand. Due to the fact that each valve has only two positions positively and accurately maintained by the snap action thereof, the Valves maybe operated with precision to selectively control both doors without so much possibility of the motorman becoming confused and improperly controlling the doors in a manner hazardous to pas'- sengers.

As both control Valves are identical in construction, a description of one will suffice for both. Each valve comprises a casing Ill, which for ease of assembly and repair, includes an intermediate section Il, a bottom section l2 and two top or upper sections I3 and I4, the latter of which are both secured to the intermediate section by means of screws i5. The bottom section is likewise secured to the intermediate section by means of the screws I6. All the parts of the casing are preferably die castings and the bottom section l2, which is the pressure side of the valve, is provided with a pair of circular cavities l1 and I8 each having concentric inwardly extending valve seats I9 and 2t, ported for communication with a common pressure inlet passage 2i, which leads to an inlet nipple 22. An exhaust aperture 23 is drilled in the base I2 to communicate with the exhaust nipple 26 also extending downwardly from the bottom of section l2. This bottom section is also provided with an integral web 25 separating the two cavities l'l and I3 and upon this web rests the central web or partition 26 of the intermediate section and constitutes a dividing wall between a pair of cylindrical valve chambers 28 in the intermediate section coaxial with the cavities Il and I8. Formed on this intermediate section to communicate with valve chamber 28 is a threaded nipple 29, while a corresponding nipple 30 communicates with the valve chamber 2l.

The valve chambers 21 and 28 are respectively concentric with cavities I1 and I8 in the base, and the top of the valve chambers are provided, each with a concentric valve seat 3| and 32, and like the other two valve seats I9 and 20, extend inwardly or their respective valve chambers to be arranged in opposed relationship therewith. The valve seats 3l and 32 communicate the upper ends of the valve chambers with a common exhaust passage 33 having branches 34 communicating with the exhaust passage 23 in the base. With such an arrangement, the nipples 29 and 30 alternately serve as pressure and exhaustV ports, as will be presently obvious. This intermediate section is provided on opposite sides with external apertured lugs for mounting the valve casing on a suitable support.

Disposed in each valve chamber is a polygonal, double-ended poppet valve 35, normally biased away from its lower valve seat and the pressure side of the valve by means of a coil spring 36 seated in the cavity surrounding the valve seat 20 in the base I2, which spring presses the upper end of the valve body against its upper seat 32. 'Ihis places the lower end of the valve chamber 28 in communication with the inlet admitting a medium under pressure which has an only means of escape, through nipple 29, due to the valve being normally forced against its upper valve seat 32. A rubber or other suitable composition block 31 is secured in a recess in the lower end of each valve body, while a similar elastic piece 39 is secured in the upper end of the body to engage the adjacent valve seat without marring or scuiing either the seat or the valve body and insuring a tight seal at all times, irrespective of the presence of dust or other extraneous matter in the valve. The other poppet valve body is designated by the numeral 39, and is adapted to alternately seat upon the valve seats I9 and 3| of valve chamber 21. The valve bodies are provided with valve stems 40 and 4I which extend all the way through the valve body and have their lower ends riveted over as shown, while their upper ends extend through their respective valve seats and partition above into an upper cavity 42 in the upper end of the intermediate section II to be engaged and operated by snap action operating mechanism which simultaneously moves the valve bodies 35 and 39 in opposite directions, to alternately open the valve seats in each valve chamber.

In order to predominate over the valve biasing means and to force one valve body under pressure against its pressure seat and off of its exhaust seat while the other valve is retained under pressure against this exhaust seat to uncover its pressure seat, the snap action mechanism employs a spring exercised toggle embodying an operating handle 43 and cam 44 concentrically and independently mounted upon a fulcrum pin 45 secured in spaced depending ears 46 of casing section I4, which disposes the axis or fulcrum of the toggle down within the recess 42. The operating lever 43 is disposed between a pair of pear-shaped plates 46 constituting the cam and the plates are disposed between the depending ears 46. On opposite sides of the pivot 45, valve sternA engaging rollers 41 are mounted between the two cam plates to move substantially in the paths of movement of these valve stems, upon rocking movements of the cam. The cam plates are extended a distance below the pivot 45 where a spring mounting pin 48 having an enlarged medial portion to be disposed between the two cam plates with oppositely extending portions, can pass through the cam plates and extend therebeyond a substantial distance as best shown in Fig. 3. The ends of this pin 48 are grooved for the anchorage of corresponding ends of a pair of coil springs 49, which have their opposite ends engaged with the grooved ends of a roller carrying pin 50 which has a polygonal medial portion 5I to be slidably engaged in a slot 52 of the operating lever above the cam. On this pin 5i) on opposite sides of the operating lever are mounted cam engaging rollers 52 held engaged with the developed edges of the cam plates by flanges through the medium of detachable snap rings 53, snapped into grooves in the pin 59. Thus, it will be seen that the tension springs 49 always tend to hold the elbow of the toggle mechanism in angular relation to hold the operating lever in either of its two extreme positions with the cam rocked to one side or the other, so that one valve body 35 or 39 is held against its pressure seat while the other valve body is held off of its pressure seat and into engagement with its exhaust seat.

In order to assure the operating lever being held in either oi its two positions, the cam plates are developed with an intermediate ramp, lobe or apex 53 arranged equi-distant from the two rollers 41 so that as the operating lever is moved toward the apex of the cam, the rollers 52 are moved upwardly to further tension the springs 49 in order that the operating handle will be immediately thrown over the axis of the cam to its other extreme position as soon as the rollers pass the apex. It will of course be apparent that the spring mounting pin 43 is also located equidistant from the rollers 41 below the pivot pin 45 so that the tension springs 49 will snap the lower portions of the cam plates over to whichever side of the casing the operating handle is disposed upon. The operating handle 43 is provided with shoulders on opposite sides to engage stop S for limiting the throw of the lever in both directions and in order to absorb the impact and deaden sound, a rubber buier strip 54 or any other suitable material is seated in a recess in each side of the top of the casing as shown in Fig. 4. By making the upper sections i3 and I4 detachable from the valve casing, they can be separately removed and with them the entire snap action mechanism cam can be withdrawn from the casing.

In operation, when the parts are in the positions shown in Fig. 2, the actuating medium from a suitable source of pressure passes into each valve casing Il! through the nipple 22 to enter valve chamber 28 and pass through nipple 29 to the device to be operated. The operating medium returning to the valve from such device enters the nipple 39 of the valve and passes through valve chamber 21 to the exhaust passages 33 and 34 and out through the common exhaust nipple 24 in the bottom of the valve to the atmosphere.

To reverse the valve, its Valve lever 43 is moved to the left of Fig. 2 causing the lever rollers 52 to roll up the cams 46 toward their high points or apices 53 which will not disturb the positions of the two valve bodies 35 and 39 until these rollers pass over the high points of the cams, when the springs 49 will immediately predominate and cause the toggle to reverse itself to press down upon valve stem 4I. This causes the valve body 35 to be pressed upon its lower seat 29 against the tension of the coil spring 36, while the other valve engaging roller 4l moves upwardly permitting the spring under valve body 39 to raise it forcibly into engagement with its exhaust seat 3l. Thus, the medium under pressure instead of entering valve chamber 28 will enter valve chamber 2l and pass through the nipple 30 to the device to be operated. Fluid medium is exhausted from said device by returning to the valve and nipple 29, where it is conducted to chamber 28, then through the valve seat 32, to the port 34 from whence it is conducted to the atmosphere through the exhaust nipple 2li. Since the valve has no delicate intermediate position it can be positively operated with a minimum possibility of error on the part of the motorman.

Due to the particular biasing of the valve bodies, they are held to their seats under pressure so that there is no danger of the valves iiuttering due to normal pressure or pressure build-up, especially on the pressure side of the valve due to the predominance of springs 49 over the springs which hold the valves upon the exhaust seats.

It is to be understood that various changes in the construction and arrangement of the device can be made without departing from the protection afforded hereby. Having described the coristruction and operation of the invention, I claim:

l. A valve mechanism comprising a casing having a pair of valve chambers, each provided with a valve seat, a valve body in each of said chambers, spring means normally tending to force said valve bodies 01T of said seats, a snap action mechanism connected with said valves and including a rockable cam with a developed apex and being mounted upon an axis, an operating lever mounted co-axially therewith and having a roller engaging the cam, and a spring connect- Ving said roller of the lever with the cam at a point in alignment with a line connecting the cam apex and its axis and normally predominating over said rst named spring means whereby one of the valves is resiliently forced upon'its seat while the other valve is moved off of its seat upon movement of said lever from one position to another.

2. A valve mechanism comprising a casing having a pair of valve chambers, each provided with a valve seat, a valve body in each of said chambers and having a valve stem, spring means normally tending to force said valve bodies ofi of said seats, a snap action mechanism including stems, a pointed lobe on the cam spaced equidistant from the rollers, a roller carried by the l'ever and engaging the camming surface of the cam and being incapable of remaining stationary upon the point of said lobe, and a spring connecting said roller and cam for predominating over said spring means whereby the operating handle is moved across said lobe to resiliently force one valve upon its seat while the other valve is moved off of its corresponding seat upon movement of said handle from one position to another.

3. A valve mechanism comprising a casing having a pair of valve chambers, each chamber being provided with a valve seat, a Valve body in each of said chambers and having a valve stem, spring means normally tending to force said valve bodies oii oi said seats, a snap action mechanism including a two position handle and a cam mounted on a pivot, said cam having means to engage the ends of said valvestems, said cam having an apex equidistant from said last named means, an axle mounted to move longitudinally of said lever and having a roller engaging said cam contour, and a spring connecting said axle and cam for enabling the roller to move over said apex to resiliently force one valve upon its seat while the other valve is moved oi of its corresponding seat upon movement of said handle from one of its positions to another thereof.

4, A valve mechanism for operating a door engine comprising a casing having a pair of'valve chambers, each provided with opposed inlet and exhaust valve seats, a double valve body in each of said chambers and having a valve stem, spring means normally tending to force each valve body oii of its inlet seat and upon its exhaust seat, a snap action mechanism for simultaneously operating both valves and having a two position handle, a cam having means at opposite sides for alternately actuating said valve stems in opposite directions, said cam having a high point midway between said means, a roller carried by said handle and engaging said cam contour, and a spring connecting said roller and vcam for enabling the roller to move over the high point of the cam to resiliently force one valve upon its seat while the other valve is moved off of its corresponding seat upon movement of said handle kfrom one of its positions to another thereof.

5. A snap action mechanism for valves comprising a rockable cam mounted upon an axis and having an apex, an operating lever independently mounted coaxially therewith and having a roller engaging the cams contour, and a spring connecting said roller of the lever with the cam at a point in alignment with a line drawn through the cam apex and its axis.

J OI-IN R. ALMOND.

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