US2914240A - Air compressor - Google Patents

Description

S. VORECH AIR COMPRESSOR NUV., 24, 1959 3 Sheets-Sheet 1 Filed April '7. 1955 Naw, 24, 1959 5 Sheets-Sheet 2 Filed April 7. 1955 Nov, 24, 1959 s. VORECH 2,914,240

AIR COMPRESSOR Filed. April '7. 1955 3 Sheets-Sheet I5 I N VENTOR ST55/15N W550/1, 05054550 BY MARGARH W550/1 y ADM/Ms ma rmx BY La MM/4% ATTORNEYS United States Patent() ArRcoMPREssoR Application April 7, 1955, Serial No. 499,852l Y, j. i

7 claims. (Cl. 2304-34) This invention relates to air compressors and more particularly to an improved air compressor of the type operated by the relative movement between a vehicle frame and an axle part. j

vOne object of the present invention is 'to provide an improved air compressor of the above 'type' which is particularly adapted for supplying air to airhorns or other equipment on automotive vehicles. v

Another object of the invention isto provide anair compressor of the above type which has associated therewith improved actuating means for operating'the compressingmeans. f

Another object of the invention is to provide an air compressor of the above type which readily compensates itself for Variations in the relative movement between the frame and axle part due to road action on the vehicle.

Still another object of the invention is to provide an air compressor of the above type which mechanically predetermines the maximum pressure output without a sacrice of volumetric e'lciency and also eliminates the necessity for a separate pressure governing device usually associated with compressor installations.

Other objects and their attendant advantages will become apparent as the following detailed description is read in conjunction with the accompanying drawings wherein: f

Fig. l is a vertical sectional view of the compressor of the present invention;

Fig. 2 is a change position View similar to Fig. l but showing the actuating means of the compressor at about oneahalf of its limit of movement; and 1 Fig. 3 is a change position view similar to Fig. 2- `but showing the compressor actuating means at the upper end of its limit of movement.

A compressor embodying the invention is illustrated in Fig. l wherein the frame which may be a portion of a vehicle crank-case on some other portion adjacent an axle has secured thereto a compressor casing member member 11 containing at its upper end a compression cylinder 12 containing a piston member 13 having usual sealing rings 14 of any suitable substance. The cylinder portion 12 of the compressor has at its upper end an outlet port 15 communicating withva valve chamber 16 which in turn communicates through opening 17 with a conventional storage tank (not shown). The outlet port 15 is controlled by a discharge or outlet valve 18 of the disc type which is normally retained in its closed position by the existing air pressure in the storage tank and by a spring 19 interposed between the upper surface of the Valve and a recessed valve chamber closure member 20. The spring 19 serves to retain the valve 18 closed until a predetermined pressure above existing storage tank pressure is reached in the cylinder 12 at which time the force of the spring is overcome and the valve 18 unseated to permit the passage of compressed air to the storage tank.

The piston 13 is reciprocated by actuating'means, later described in detail, responsive to the relative movement l12 has dropped to just below atmospheric.

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between the vehicle axle and the frame portion 10 to which the compressor casing 11 is attached. The piston 13 is operatively connected to the actuating means by a hollow piston rod 21 which may be threadedly attached at its lower end to a member of the actuating means later described. The upper portion of the hollow piston rod 21 forms an inlet chamber 22 which is communicated with atmospheric pressure through lateral openings 23. The upper end of chamber 22 is provided with` an inlet port 24 which is normally closed by a disc valve 25 operating in a recess 26 formed in a type inlet valve closure member 27 secured in the upper face of the piston 13. The recess 26 is communicated with the interior of cylinder 12 by vertical passageways 28 and the valve 25 is normally retained closed by a light spring 29 interposed between the upper surface of said valve and the upper wall of the recess. The spring 29 is designed `to permit valve 25 to open when the piston has started its down-stroke and the pressure in cylinder Upon this occurrence atmospheric air passes through openings 23 into inlet chamber 22 whence it proceeds via inlet port 24 and vertical passagewayV 28 to the interior of cylinder 12 which is thus recharged for the next succeeding up-stroke of piston 13.

The compressor casing 11 below the cylinder 12 bells outwardly to provide an upper chamber 30 which is an extension of a larger lower chamber 31. chamber 30 is separated from the cylinder 12 by a shoulder 32 and the lower chamber 31 is separated from the upper by a second shoulder 33. An openingv 34 through the wall of casing 11 ysubjects the chambers at all times to atmospheric pressure.

The chambers 30 and 31 cooperate with the piston actuating means which comprise in part a cup-shaped member 35 having a cylindrical cavity 36 and lateral flanges 37 of a size to slidingly operate in the lower chamber 31 between the shoulder 33 and an annular retaining ring 38 seated in a groove about the lower inner surface of the chamber. The member 35 is xed to the piston rod 21 through the medium of an elongated shouldered bolt-like member 39 which is threaded into the piston rod to clamp the upper wall of the cup-shaped member 35 between the shoulder of member 39 and the lower end of piston rod 21. The cup-shaped member 35 and hence piston 13 are normally retained in the position shown in Fig. l by a return spring 40 interposed between the upper surface of ange 37 and the upper shoulder 32 of upper chamber 30.

The bolt-like member 39 projects downwardly through cavity 36 and extends beneath casing 11 where an enlarged head 41 integral with member 39 is engaged by an annular llange 42 integral withl a sleeve member 43 slidable with respect to member 39 and having an external diameter of a size enabling the sleeve to enter the cavity 36 of the cupshaped member35 as occasion demands. sleeve 43 has an outwardly projecting flange 44 and the cup-shaped member 35 has a lateral ange 37. Interposed between ilanges 44 and 37 is a compression vspring 46 which normally tendsr to retain the sleeve 43 in its extended position of Figure 1. The iange 37 may be provided with an annular lip 45 and the flange 44 may be provided with an upwardly extending shoulder 56 for the purpose of providing a guide at each end of the spring 46 to maintain concentricity of the spring with respect to the adjacent elements. In accordance with the invention and for reasons to become apparent, the initial preload strength of the spring 46 is greater than the collapsed or final strength of the return spring 40.

The spring 46 of Fig. 2 is initially preloaded to a force slightly higher than the nal desired force on the piston 13 as determined by the desired final tank pressure Thel upper The and the collapsed force of the return spring 40. Spring 46 under this condition serves the purpose of a pressure governing device as increased pressures above the established maximum cause partial compression Vof the spring 46. f v i In accordance with the invention, relative motion between sprung parts of the vehicle is transmitted to the piston 13 through the medium of an actuating lever 47 having one end pivoted at 48 to a bracket 49 xed to the same portion of the vehicle as the casing 11. The opposlte end of the lever 47 mounts a roller 50 engagmg a bracket 51 which forms an axle part and is preferably mounted on the axle of the vehicle, it being understood that the portion of the vehicle mounting bracket 51 has relative motion to the-portion of the vehicle mounting the pivoted` end of the lever 47, said relative motion being usually the result of roadaction on the vehicle. Intermediate the ends of lever 47 is a second roller 52 which engages a bearing cap member 53 secured in the lower end of the aforedescribed sleeve 43, the intermediate roller 52 being retained in engagement with the cap 53 by a tension spring 54 fixed at one en d to the frame 10 and at the other to a suitable projection 55 on lever 47.

a '.I'he movement of lever 47 between the extreme positions of Fig. l and Fig. 3, and hence the motion imparted to the compressor parts through the action of the intermediate roller 52 on sleeve 43, is preferably a function of the compression travel limits of usual shock absorbers employed on vehicles. The normal position of the actuating lever 47 is shown in Fig. 1 with roller 50 1n contact with axle bracket 51, and intermediate roller 52 in contact with cap 53 of sleeve 43. The distance between the position of axle roller 50 in Fig. l and the position of roller 50 in Fig. 3 represents the compression travel limits of the shock absorbers and the distance between the positions in Figs. l and 3 of the intermediate roller 52 indicates the limits of travel of sleeve 43. However, in accordance with the invention, the compression stroke of piston 13 is considerably less than the limits of travel above described in order that the compressor will compensate itself for variations in relative movement between the frame and axle part resulting from variations in road action on the vehicle. This will become apparent as the description of operation of the compressor proceeds.

In operation, when the axle bracket 51 moves from the position of Fig. l towards the position of Fig. 3, intermediate roller 52 acts on cap 53 to move sleeve 43 upwardly thereby imparting through spring 46 movement to cup-shaped member 35 and attached piston rod 21. Since the spring 46 has greater strength or loading than return spring 40 the latter only is collapsed during the initial movement of the actuating lever from the position of Fig. l t0 that of Fig. 2. As the piston 13 approaches the top of its stroke, pressure in cylinder 12 increases until it balances the existing pressure beat the extreme upper limit of sleeve movement, the upper side of bearing cap 53 strikes the lower surface of the enlarged head 41 of bolt-like member 39 to provide a stop for sleeve 43. At this stage all the elements of the compressor take the position shown in Fig. 3.

Upon completion of upward movement of the various elements of the compressor and after the axle-bracket 51 has started its downward movement, the piston 13 remains at the top of its stroke while the lever 47 is returning to the position of Fig. 2 under the influence of spring 46 whereat the flange 42 of sleeve 43 engages the head 41 of member 39. As the lever 47 and its attached rollers continue from the position of Fig. 2 to that of Fig'. l, return spring 40 and compressed clearance-air force piston 13 back towards the end of its suction stroke. When the pressure in the cylinder drops to slightly below atmospheric, air ows through opening 34 in the wall of casing 11 and thence through the inlet chamber and..ports in the piston rod 21 lifting inlet valve 25 from its seat to charge the cylinder 12. At the end of the suction stroke valve spring 29 forces valve 25 to its seat,trapping the air in the cylinder in readiness for the next compression stroke.

. It is contemplated that during the rebound stroke of the shock absorbers of the vehicle, axle bracket 51 would in all probabilityV move downwardly faster than lever 47 can be returned by spring 46. However, under these conditions tension spring 54 maintains contact at all times between intermediate roller 52 and the bearhind discharge valve 18 at which time the valve lifts from its seat to permit the escapeof air from the cylinder to the storage tank. At this juncture, the parts of the compressor take the positions illustrated in Fig. 2. At the end of the stroke, valve spring 19 forces the valve back to its seat, thus preventing back-flow of air to the cylinder. With the lever 47 at the position of Fig. 2 further upward movement of the piston 13 is prevented due to impingement of the upper surface of ange 37 of cup-shaped member 35 with shoulder 33, the latter shoulder thus functioning as a stop means. As the lever 47 continues to move from the position of Fig. 2 to the position of Fig. 3, further motion of the piston rod being now stopped by the shoulder 33 as aforesaid, the heavy spring 46 commences to collapse and sleeve 43 slides with respect to the bolt-like merning cap 53.

it is oeneved that from the description herein it will be readily apparent as to the manner in which the compressor compensates itself for variations in road action on the i vehicle. For relatively mild road action wherein the lever i7 isnot moved beyond the position of Fig. 2, the compressor nevertheless delivers one full compression stroke. Where the road action is much more severe than this so that the shock absorbers travel their designed limits and the lever 47 moves to the position of Fig. 3, the compressor deliversV a fulll compression stroke but without danger of over-travel `of the piston 13 inits cylinder 12. For any degree of movement intermediate the positions of Figs. 2 and 3 the compressor in like manner delivers a full-stroke and thus the compressor may be said to compensate itself for the variations in relative movement between the frame and axle part. After repeated compression'strokes, assuming no air is being used, the tank pressure will finally reach a predetermined maximum as determined by the. initial preload of the spring 46 where increased( pressure on the` piston 13 will cause a proportional compression of the spring 46 thereby limiting the maximum pressure output of the compressor. For lever movementbetween positions of Figs. l and 2, the compressor will' still deliver, though such delivery will, of coursebe dependent upon the back pressure exerted from the storage tank on the. discharge valve 18. However, by varying the length of lever 47, or the position of the rollersthereon, or the position and length of the mount ing brackets, thecompressor may be made to deliver a full compression stroke for any desired degree of relative movement between the sprung parts of the vehicle. Furthermore, by variations in design of the type just described, the stroke ofthe compressing meansmay be lengthened or shortened any desired amount. This renders the actuating means-of the invention adaptable to any known type of compressing means such as a diaphragm, piston ring type, etc., `anduhence the invention is not intended to be restricted exclusively to the piston type compressor shown and described.

The present invention `provides an inexpensive road-action operated compressor having a minimum of moving parts which, due to its improved actuating means, is readily adaptable to any type of vehicle and any type of road condition which might be encountered by a vehicle. As pointed out above, the invention is susceptible of many variations and modiiications without departing from the scope and spirit of the appended claims.

What is claimed is:

1. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movements of said parts, comprising a cylinder carried by said frame part, a member movable in opposite directions in said cylinder to compress air, means connected with said member and including a rst spring for moving said member in one direction, other means including a second spring for moving said member in the opposite direction, the loading of said second spring being greater than that of the rst named spring, a lever having one end pivoted to said frame part and the other end operatively connected with said axle part, and means operatively connecting the lever intermediate its ends with said other means.

2. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movements of said parts, comprising a cylinder carried by said frame part, a member movable in opposite directions in said cylinder to compress air, means connected with said axle part and including a first spring for moving said member in one direction, stop means connected with the cylinder for limiting the movement of said member in said one direction, means including a second spring operatively connected with said member for moving said member in the opposite direction, the loading of said first spring being greater than the loading of said second spring, said first spring being compressed by said moving means upon engagement of said member with said stop means.

3. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movements of said parts, comprising a cylinder carried by said frame part, a member movable in opposite directions in said cylinder to compress air, a lever having one end pivoted to said frame part and the other end operatively connected with said axle part, a first spring operatively connecting said lever and said member, motion of said lever in one direction being imparted to said member through said spring, means including a second spring for moving said member in the opposite direction, a stop in the cylinder for limiting the movement of said member in the first direction, the loading of said first spring being greater than the loading of said second spring whereby said rst spring is distorted by the movement of said lever only after engagement of said member with said stop.

4. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movement of said parts comprising a cylinder carried by said frame part, a piston in said cylinder, inlet and outlet valves associated with said cylinder, a member connected to said piston and extending exteriorly of said cylinder, a second member connected to said iirst member and provided with a ange, a return spring interposed between one side of said ange and the end of said cylinder, a lever having one end pivoted to said frame part and the other end operatively connected with said axle part, means including a second spring interposed between an intermediate portion of said lever and the opposite side of said flange, the loading of said second spring being greater than the loading of said first spring, said second spring serving to transmit movement of said lever in one direction to said flange and said piston, and a stop in the cylinder engageable by said ange upon predetermined travel in said one direction to limit the stroke of said piston, said second spring being thereafter collapsed upon further movement of said lever in said one direction whereby the lever may have greater travel than the stroke of said piston.

5. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movement of said parts comprising a cylinder carried by said frame part, a piston in said cylinder, inlet and outlet valves associated with said cylinder, a rst member connected to said piston and having an extended portion, a second member connected to said first member above said extended portion and having a flange, a sleeve slidable on said extended portion and having a flange at its lower end, a return spring interposed between one end of said cylinder and one side of said first named liange, a second spring interposed between the other side of said first named flange and the ange on said sleeve, the loading of said second spring being greater than the loading of said first spring, a lever having one end pivoted to said frame part and the opposite end operatively connected to said axle part with its intermediate portion operatively connected with the otherside of said ange on said sleeve, and a stop in the cylinder engageable by said rst named ange upon its being moved a predetermined distance by the action of said lever on said second spring, said second spring being thereafter collapsed to enable continued movement of said lever a greater distance than the movement of said piston by the sliding of said sleeve on the extended portion of said piston rod.

6. The compressor in accordance with claim 5 and including a tension spring connected between said frame part and said lever to retain the intermediate portion of said lever in engagement at all times with said sleeve.

7. In a vehicle having relatively movable frame and axle parts, an air compressor operable upon relative movements of said parts, comprising a cylinder carried by said frame part,` a member movable in opposite directions in said cylinder to compress air, means connected with said member and including a rst spring for moving said member in one direction, other means operatively connected with said axle part and including a second spring for moving said member in the opposite direction, the loading of said second spring being greater than that of the first named spring, and loading of said second spring being approximately equal to the maximum desired output force of said movable member.

References Cited in the tile of this patent UNITED STATES PATENTS 628,727 Schumacher July 11, 1899 999,590 Priesuy Aug. 1, 1911 1,731,145 MacMillin Oct. 8, 1929 2,100,972 Michaels Nov. 30, 1937

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