US2199482A - Air compressor - Google Patents

Description

May 7, 1940 N. A. cHRlsTENSEN 2,199,482

AIR coMPnEssoR Original Filed Oct. 1952 3 sheetysheet l 'l A ORNEY.

May 7, N. A. cHRls'rENsEN 2,199.482

AIR COMPRESSOR v A original Filed ot. 1'7,c 1932 3 Sheetsheet 2 ATTORNEY.

- 40 tion of Patented May 7, 1940 `PATENT en -*FICE y 2,199,482 Am COMPRESSOR Niels A nton Christensen, south Euclid, ohio Original application October- 17, 1932,l Serial No. 638,123. Divided and this application Febru' ary 24, 1937, Serial No., 127,511 1 'l 7 claims.

This invention relates generally to air compressors and is a division of my co-pending application Serial No. 638,123 illed October 1'?,l

1932, for Air compressors and an important ob- 5 ject of the invention is to provide inexpensive valve construction for compressors, which, under ordinary conditions have tendencies to set up a singing reed action, but with the construction and arrangement herein provided, `these valves are 19 oatinglyretained in position to counteract any tendencies for the valves to set up humming or whirring sounds.

A further object of the invention is to reduce machining of the cylinder head to a minimum 15 by provision of a simple and durable valve seat member.

Another object of the invention isA to provide an improved form of spring for the governor control which will not bedas subject toJatigue -20' and crystallization as the more usual form'of compression coiled springsemployed for this purpose and will be considerably cheaper.

Other objects and advantages of the invention will become apparent during the course of the 125 following description.

In the accompanying drawings forming a. part of the description and wherein like numerals are `employed to designate like parts throughout the several views:

Fig. 1 is a side elevation of an air compressor with governor control,

` Fig. 2 is a longitudinal vertical section of the same,

Fig. 3 is a top plan of the compressor with the A35 head ofthe cylinder and governor control removed. l

Fig. 4 is an enlarged perspective view of half oi' the improved type of baille,

Fig. 5 is an enlarged side elevation of a por` the trigger mechanism of the governor illustrating the new type of spring release for the inlet valve,

Fig. 6 is a bottom plan of ,the cylinder head with a dotted circular line indicating the relative op- 45 erative position of the cylinder walls overlapping the ends 'of the valve guard for preventing a. c cidental displacement thereof,

Fig. `6a is a fragmentary section through the discharge valve of the above form of-cylinder 5o head.

Fig. '7 is a fragmentary vertical section through a portion of the cylinder head showing the in 'Y w-ietsvaivewin operative position,y

Fig. 8 isa'jenlarged perspective view of the 55 improved valve and guard therefor,

(clase-22s) a Fig. 9 is a bottom plan of a moained Iferm or cylinder head, and valve plate assembly,

Fig. 10 is a longitudinal section of the same on line III-I of Fig. 9, and

Fig. 11 is a transverse section of the same on l line II-I I of Fig.' 9.

Referring now more speciiically to the drawings for further details, the numeral III designates thecrankcaee portion of an air compressorl having openings in opposite ends fof thefattachment of bearings "di, having suita le bushings for mounting a -compressor cranks aft I2. 'I'his crankshaft may be connected directly or geared in any suitable manner 4to a crankshaft of a prime mover, not illustrated, as this connection is Well understood from the prior art and' my several prior patents. The bottom of this'crankcase castingv is closed and sealed by a removable plate I3 giving access to the enclosed parts. One side of the casting is provided with a illler I4 J4having an overflow to the engine crankcase as s hown in Fig. 1, and the saine side is equipped with an integral lateral enlargement I which is hollow andiitcommunicates with the interior of the crankcase at its lower end and at its upper end has threaded therein a breather tube I6.

The top of this crankcase is of course open for the projection of connecting rods I1- which are bored out and connected at their lower ends by bearings Il to the crank portions of the shaft y I2. This crankshaft has a longitudinally extending lubricant passage which communicates with the hollow connecting rods whereby lubricant may be forcedto the upper ends thereof to lubricate the wrist pins I9 journaled in pistons 20. The present improvements have been. illustrated in conjunction with atwin compressor but of course may be employed in the manner hereinafter speciiied in a; single cylinder -compressor as will be obvious as the description proceeds.

The tcp of the crankcase for a twincomlpresser is provided with a pair of circular communicating openings dening generally the shape of the numeral 8 so that the bore of a twin cylinder 2| may register therewith as illustrated. Seats 22 are provided continuously around the edges of these openings` and downwardly in clined shoulders 23, at opposite ends of the openings are provided to deiiect any lubricantrunning down the same on to the crankcase bearA ings. In order to prevent lubrication from being thrown up into the cylinders 2 I by the crankshaft during its rotation, bafe means are clamped upon the seat 2 2 by bolting-the cylinder portion upon the .crankcase The baille means'in the w by such or equivalent means.

present illustration are composed of "a pair of plates Vor stampings 24, best seen in Figs. 3 and 4, possessing a shape generally similar to the numeral 3 in the case of a twin compressor; while in the case of a single compressor, the baille means would be constituted by a pair of semicircular plates, or one-half of the bailles for the twin compressor. Each of the baille plates has an outline corresponding to one-half of the seat 22 of the crankcase portion and its margine25 is iiat to snugly t the seat 22 with the exception of portions spaced equi-distant from its straight inner edge 26 where the margin is provided with upwardly deflected and curvedlips 21. The body portion of each end of each baille plate is provided with a semi-spherical bulged or emboss'ed portion 26 which is concentric withV the adjoining marginal portion of the baille plate. A series of apertures 29 are provided in the ilat `marginal portion 25 of the bailleY plate at the base of the bulged portion in circumferential relationship Ato be concentric with the semi-circular end portions of the baille. l In .some cases, these apertures may extend into the bulged portions to facilitate the passage of any liquid lubricant from the cylinders back vinto the crankcase. As appreciated from Fig. 2, the openings of the ends of the baille plates are disposed above the inclined ledges or shoulders 23 so that the latter will guide 'any returning lubricant and spill the same upon the crankshaft bearings.

The central portion of each bulge 28 is removed to provide each Isection-of the bale with an opening 30, extending from the inner straight edge 26 of the baille plate throughout the bulged portion to touch the flat marginal portion 25 and thereby provide, with its complementary baille section, an elongated slot 3|, havingits longest dimension diametrically of the cylinder to accommodate the projection of the connecting rod I1 into the cylinders 2|. Opposite edges n of each notch or opening 30 adjacent the straight edge 26 and the crest of the humps are flattened as indicated at 32 to bedisposed substantially in a plane parallel to the plane of the vfiat margins 25. Obviou/sly the raised portions 28 v.prevent lubricant overowing into openings 30 and being carried upwards by the connecting rods.

Two of these. complementary baille-plates as shown in Fig. 4 are placed together with their straight edges 26 abutting and their ,at margins resting in the seat 22 ofthe crankcase as shown in Fig. 3,' and with their bulged portions 28 ex-` tending upwardly and slightly into the lower ends of the bores of the cylinder 2|. vWhen the cylinder is bolted on to the crankcase by the bolts 33, with a gasket disposed between the bottom of the cylinder and the`flat'marginal portions 25 of the baiiles, the lips 21 will be depressed into the gasket to increase the frictional lock between the parts and to prevent accidental rattling or rotation of the baille plates, when used in a single cylinder compressor where the two complementary baiiies form a circular baille plate and may have a tendency to rotate if not ,precluded The slots or ,openings 30 in the baiiles are of such dimensions to afford proper clearance for the connecting rods I1 and yet yare of a size to preclude lubricant being thrown up into the cylinder by rotation of the crankshaft. The openings 23 also permit the passage of lubricant vapor up into the cylinder 2| and still provide ample drainage of any oil dropping from the wrist pins, cylinders or pistons back into the crankcase:

same in open position A head 34 is suitably bolted on the cylinders 2| and incorporates therein inlet and outlet valves, the former being fed atmospheric air through the passageway 35 drawn in through the air cleaner 36. An automatically acting governor mechanism is indicated in general by the numeral 31 and includes a' pressure Sylphon housed in chamber 38 and actuated by reservoir pressure to automatically open the inlet valve 4| when reservoir pressure reaches a predetermined amount. This type of inlet valve constructed from thin sheet spring' steel is generally shown in my prior Patent No. 1,798,440 granted March 17,1931 and it is one of the objects of this invention to improve the construction of the inlet valve and guard member and obviate any hum of the valve due to air currents passing the same, setting up a reed action. The construction of the cylinder head in Figs. 6 and 7 of the formation of the valve and guard seats is generally the same as in my previous patentit being noted that the valve seats and parts have their center line located in a chordal line relative to the bore of the cylinder as indicated in dotted lines in Fig. 6.

The inlet ports 39 from passage 35, extend into the bottom of a valve seating recess, against which a floating. valve pin of thin sheet spring steel normally seats under its inherent spring action and the manner in which it is mounted. A valve guard 42 of less Width than the recess 40 is provided for retaining the valve inoperative position and also has the function of preventing broken valves from' falling intothe cylinder. One end 43 of the guard member is provided with a pin 44 removably fitting in a cavity 45'provided in the bottom of the recess 40, the pin passin g through an aperture 46 in one end of the leaf spring valve with suiiicient clearance to prevent the spring `valve 4| being held too rigidly at one end. This end oi' the valve guard is provided adjacent the pin 44 with a transverse shoulder 41 having a height slightly greater than the thickness of the leaf spring valve. The pin retains the end of the spring slightly spaced from the shoulder 41 and also retains the free end of spring spaced from the end wall of recess 40.

The surface 43 of the guard member next to the leaf spring valve is tapered from a transverse shoulder 42' adjacent the pin 44 to a point adjacentv the other end of the guard where the surface, then, is angularly disposed in a plane parallel to its outer surface. The end of the guard is seated in a recess 43 in the bottom of the cylinder head so that the entire outer surface oi.' the valve guard member is flush with the under surface of the cylinder head whereby opposite ends of the guard member will ilt flush on the upper surface of the cylinder wall. The chordal arrangement of the guard member across the bore of the cylinder vwith its ends resting upon the cylinder walls prevents the guard and f`valve from falling into the bore. It will also be obviousthat the valve 4| in opening and closing, exes to some degree on the shoulder 42' rather than at the pin 44.

As explained in the aforesaid patent, the g'o'vernor control includes a push pin 60 slidably mounted in the cylinder head for engagement' withl the free end of th valve 4| to hold the hen reservoir pressure has reached a predetermined quantity. As better shown in Figs'. 2 and 5, the upper side ofthe push pins are provided with heads 6| normally retained in engagement with the underside of the u 'A trip pin B2 carried by a trigger member 53 'of the governor control. As shown in Fig. 2, light compression springs 54 have been employed, heretofore, for retaining the push pins 50 in elevated position wherebythe inlet valves may close upon their seats. This comprssion spring should be of strength suilicient to overcome the weight of pin 50, but due to slight vibrations at' high motor speeds and due to production difference in workmanship. and material from which these springs are made it has been found necessary to materially increase the strength of these springs beyond the mere weight of the pin 50 to such an extent as to set up ya factor which mayV mate-4 rially affect the normal ,operation of the governor. For these reasons a different type of spring has been provided as illustrated inFig. 5.

As will be readily seen, this new type of spring shown in Fig. 5 imposes no functions interfering with the normal governor operation and its strength can vary within large ranges. This modified spring comprises an intermediate coil portion 54 with one end extended horizontally and looped about push pin 50 under the head 5I. The other end 55 of the spring is directed ver-A tically and then horizontally to be disposed in an annular groove in one end of the pin 52- and In Figs.

partially coiled thereabout -to prevent accidental displacement. Such 'a spring yieldingly retains the head of the `push pin 50 against the under side of the pin 52 so that itfis elevated with pin $2 and the inlet valve functions when reservoir pressure has not reached the maximum degree. f' It is of course understood that the finger 53 is depressed by a spring pressed plunger 56 sliding over the tapered nose of the trigger whenever reservoir pressure swings the spring pressed plunger 56 vertically and exerts pressure on the trigger 53 to move the pin 50 downwardly and thereby unseat the inlet valve so that on the `compression stroke of the pistons, the air drawn `in will be idly forced out ofthe atmosphere.

However, with the push pins 50 in the position shown in Fig. 2 the inlet valves are free to seat and do so after their opening movement is compelled bythe downstroke of the pistons .and the compressed' air is then forced out through suitable.l ports and outlet valves 51 to the reservoir.

As illustrated in Figs. 6 and 6a, the outlet valve comprises small triangular plates 58 adapted to be forced to their separable seats 58 concentric with outlet ports 59 by means of small coil springs 60 carried in axial cavities of cap screws 6l threaded into openings concentric with the' port 59. As will be noted in Fig. 6, the valve plates 58 are substantially triangular shaped with their apices removed and are of such dimensionsr as to have free movement perpendicularly of their seats but not laterally thereof. Air pressure within the cylinder obviously unseats the valves, and permits' escape of air through suitable discharge passages; the'springs 60 serving to return the triangular valve plates to their seats upon the suction stroke of the piston. 'I'he lift of the outlet valves of Fig. 6a is governed by the distance between their seats 58' `and the. inner ends of the cap screws Si, necessitating accurate disposition of the valve seat ^carrying shoulder and adjustnrents o f the cap screws.

9 to 11 inclusive, a modied form of cylinder head and valve-carrying member is illustrated. In this form of device no valve seat surlaces are provided in the cylinder head and therefore a minimum of machining thereof is necessary due to the provision of a novelvalve 2,199,4ss l carrying member or plate indicated in its entirety. by the numeral 1I). Moreover, this new association of partsy obviates the necessity of separate guard members for the valves and makes it possible to locate the inlet valves centrally of the cylinder bore if desired and dispenses withv th'e chordal arrangement'of guard plates shown in Fig. 6.

The cylinder head 3l' is cast with an inlet passage 62 communicating with the lateral inlet port`63 and an exhaust passage 64 communicating with a lateral exhaust port 85. The exhaust passage 64 is provided with an outlet port for each cylinder as best seen in Fig. 11, while the cored out inlet passage 62 is provided with an inlet port 61 for each cylinder.

A valve seat carrying member` or plate 1U is I clamped between the cylinder head 34' and the' cylinder 2l with suitable gaskets interposed to seal the joints. The surface of the member 10 adjacent the cylinder head is provided with an elongated substantially oval cavity 1I above each cylinder bore in communication with an inlet port -61 for the reception of a correspondingly shaped -steel valvefseat element 12, the upper surface of which is flush with the upper surface of the element of the member 10. 'I'his valveA seat element 12 is provided with a plurality of apertures 13 in registration with the inlet port 61 and adjacent one endl isl provided with a perforation 14, for the reception of a pin fixed in v*plate 1l! and adapted for oatlngly mounting'l a valve plate 16 constructed of thin resilient sheet steel. The valve seat or plate 12 is reversible to present either top or bottom surface as a valve seat as shown in Fig. l0, and has its opposite ends beveled off in the same direction to provide a lip atfone end under which a suitable tool can be inserted for lifting the seat out of plate 10. Either the arcuate ends' of the cavity 1I or the ends of the seat 12 can be cut off with a straight edge to provide a space between the plate and its cavity y to facilitate entry,of the tool to lift the seat. Of course, the upper ,gasket effectively prevents leakage between the members 10 and 12. A valve cavity or recess 11 is located beneath the recess 1l and being'shorter in length, provides the recess 11 with shoulders at opposite ends tol seat the plate-12. The bottom wall of`the ycavity 1i at one end is just a few thousandths of an inch deeper than the leaf spring is thick and is substantially parallel to the upper surface of the member 1U to loosely receive one end of the spring valve 16. This end of the valve has an' aperture to loosely admit the pin 15. Thebottom of this end of cavity 11 adjacent the pin 15 gradually 10. `In order to automatically unload the compressor when predetermined pressure inthe reservoir is established, a governor mechanism 31.

may be provided as in the preceding application with the push pins 50. depending throughvone ofv the inlet openings 13 of the valve seat element to ex the valve 16 to an open position; such nexling of thefvalve occurring in'proidmity to .thel

shoulder 18 when maximum suction lscreated by the downstroke of the piston.

The valve carrying member mabove each cylinder bore is also provided .with an exhaust port 80, which extends all the way through the member 'I0 to communicate with the exhaust passage 86. This exhaust port 80 intermediate its ends is reduced in diameter to provide a. valve seat portion or annular shoulder 8| for the reception of a triangular shaped free floating valve 82 normally held upon its seat by a coil spring 83 fitting within a cavity 84- of the cylinder head. These exhaust valveplates have a free riding t within the enlarged portion of the exhaust ports above the seats and are automatically lifted therefrom upon the upstroke of the piston to permit the disf charge of compressed air intothe passage 6l. The cavity 84 extends through a boss 84' extending into the passage 66 directly above the port 80. This boss serves as a stop to limit the lift of valve 82 and consequently thelift is determined by the depth of the enlarged portion of port 80 and the thickness of the gasket, thereby eliminating several fussy dimensions necessary when the construction of Fig. 6a is employed. y,

From the foregoing description, it will be seen that all of the fine machining of valve seats and valve attaching means is performed upon the separate valve carrying member 10 rather thanA A readily. cleaned of carbon or other foreign matter as well as the valve seats which can be easily taken out of the member 'l0 and cleaned orl polished without disturbing or removing plate 10 from the7 cylinder.

It will of course be understood that these improvements are applicable to a single cylinder compressor as well as to prime movers and other types of pumps. It is also to be understood that `various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the appended claims.

I claim: o

1. In a compressor, the, combination .of a seat member having a port, and a exibl'e fiat spring valve seating over said port and iloatingly retained in an operative position with one end floatingly confined to cause slight fiexure oi' the valve in maximum opening and closing movements.

2. In a compressor, the combination of a cylinder, a cylinder head having an inletpassage, a

separate member clamped between the cylinder and cylinder head, said member having a valve cavity in its upper surface, the bottom of said cav- 'ity having inlet openings and forming a guard,l a

removable valve seat element closing the tcp of the cavity and having an opening adapted to ansa-isa 'communicate with the inlet passage, and a floating valve loosely mounted between the element and bottom of saidy cavity.

3. In a compressor, the combination of a cylinder head, a valve guard, and a flat spring valve mounted between the valve guard and the cylinder head, said spring valve having one endfree to flex, and having the other end loosely confined between the valve guard and the cylinder head.

4. In a compressor, the combination of a flat spring valve, a valve seat surface, and a valve guard having a stepped portion at one end adapted to engage the seat surface and be spaced therefrom a distance greater than the thickness of said valve, an inclined portion and a shoulder formed thereby adjacent to the stepped portion, the spring valve being iioatingly retained between the stepped portion of the said valve guard and the valve seat surface with clearance suill'- cient to prevent reed action.

5. In a compressor, the combination of a spring valve, a valve seat surface, and a valve guard having a stepped portion at one end adapted to engage the seat surface and be spaced therefrom a distance greater than the thickness of said valve, an inclined portion and a shoulder formed thereby adjacent to the stepped portion, the spring valve being oatingly retained between the stepped portion of the said valve'guard and the valve seat surface with clearance suilicient to prevent reed action, said valve flexing at said shoulder and having its maximum opening-limited by the inclined portion of said valve guard, and said spring valve being returned to a normal position by its own inherent spring action.

6. In a compressor, the combination with a cylinder, a cylinder head memberhavlng a re. cess, the bottom of said recess having a depression adjacent Aone end thereof, a iiat spring valve having a perforation near one end thereof, and a valve guard having a pin extending loosely through sa d perforation in the valve and into said depres on to retain said valve in restricted oating condition prevent reed action thereof during rush of air thereby.

7. In a compressor, the combination of a cyl inder, a removable cylinder head having a port, a removable plate clamped between the head and cylinder and having an elongated recess in its upper surface, the bottom of said recess hav ing a smaller valve recess providing a shoulder and having a portion of its bottom inclined and another portion thereof provided withv an upstanding pin, said plate having a port into said cylinder,a removable and reversible valve seat seated within said elongated recess upon said shoulder therein and having ports and an opening to receive said pin, and a flat spring valve loosely disposed in said valve recess and having an opening to loosely receive said pin, and said valve being adapted to seat against the bottom of said valve plate and 'to be flexed over the inclined bottom of the valve recess.

' NIELS ANTON CHRIS'I'ENSEN.

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