US3058451A - Air motor assembly - Google Patents

Description

Oct. 16, 1962 J. D. BROWN AIR MOTOR ASSEMBLY s sheets-sheet 1 Filed March 10, 1961 INVENTOR. JAMES D. BROWN BY 22; 4m

A TORNEY Oct. 16, 1962 J. D. BROWN AIR MOTOR'ASSEMBLY 3 Sheets-Sheet 2 Filed March 10, 1961 BY J W R m 0 m m V m D 8 0E E M A J 3 WIN I W M mm 9 J. D. BROWN AIR MOTOR ASSEMBLY Oct. 16, 1962 3 Sheets-Sheet 3 INVENTOR. JAMES 0. BROWN WQJM ATTORNEY Filed March 10, 1961 United States Patent 3,058,451 MOTOR ASSEMBLY James D. Brown, Salt Lake City, Utah, assignor to The Eimco Corporation, Salt Lake City, Utah, a corporation of Delaware Filed Mar. 10, 1961, Ser. No. 94,826 Claims. (Cl. 121-121) This invention relates generally to fluid driven piston motors and in particular to an improved construction of an air motor and air valve assembly.

As is well known, in piston type pneumatic motors, actuating air is admitted to the top of the piston for the power stroke and is exhausted as the piston returns to the top of the cylinder.

In a usual construction of such motors, the air valve which supplies and exhausts air in timed sequence is mounted in an associated valve housing; and the valve itself is driven by the crank shaft of the motor.

It is the primary object of this invention to provide an improved valve and valve housing in combination with a piston type air motor, which valve and housing are constructed and assembled in a certain particular manner to enable improved air flow and consequent increased power without increase in the over-all size of the assembly.

It is a further object to provide such a structure that is simple of manufacture and assembly yet has an increased life due to its manner of construction.

In order that the invention may be more readily understood and carried into effect, reference is made to the accompanying drawings which are offered by way of example only and are not to be taken as limiting the invention the scope of which is defined by the appended claims.

In such drawings:

FIG. 1 is a sectional view of a piston type air motor, valve housing and valve assembly.

FIG. 2 is an exploded partial view, showing further the relationship and details of the various elements of the assembly shown in FIG. 1.

FIG. 3 is a view taken in the plane of line 3-3 of FIG. 2.

FIG. 4 is a view taken in the plane of lines t -4 of FIG. 1, the valve housing and valve being entirely omitted for purposes of clarity.

FIG. 5 is a view taken in the plane of line 5-5 of FIG. 3.

In the drawings, there is shown an air motor assembly comprising generally a motor housing in which there is suitably mounted a crankshaft 11 to which are afiixed in the usual fashion a plurality of piston 12, mounted to reciprocate in cylindrical housings 13. As is customary, the pistons are connected to the throw arm of the crankshaft by means of connecting rods 15 which are journalled at one end to the crankshaft 11 and at the other end to wrist pins 14.

Communicating with the top of each cylinder is an air passage 16 which communicates with the interior of a valve housing 17 afiixed to the motor housing.

The valve housing 17 is a cast unitary structure fitted into a bore 18 in one side plate of the motor housing and fixedly connected thereto by means of equally spaced bolts 19 which serve to position the valve housing for proper timing of air flow. Precise positioning of the valve housing is further insured by means of a dowel pin 21 which is adapted to fit into any one of the five recesses 22 spaced at 72 intervals about the face of the motor housing in spaced relationship to the bore.

As is best shown in FIG. 2, there is provided a valve body 25 adapted to be rotatably received in the valve housing and to accommodate air flow in known fashion in proper sequence upon rotation. In this connection, the

3,058,451 Patented Oct. 16, 1962 valve is provided with suitable ports such as 26, 27, 28 and 29. Of these, ports 27 and 28 are suitable for either infiow or outflow of air depending upon reverse or forward driving of the motor, while port 26 provides the major air exhaust through the center of the valve body in known manner.

Annular air passages 31 and 32 are provided in the valve housing to communicate with plenum chambers such as 31'. 7

As the valve rotates, incoming air is admitted through one of the first mentioned passages whence it passes into the communicating air passage leading to the top of the cylindrical section. Upon further rotation exhaust cores come into communication with the air passages and, as the piston rises in the cylinder, air is forced out through the exhausts. 7

It is the most significant feature of this invention that the valve body and housing are each cast as unitary members. The use of such cast structures is enabled by the positive journalling of the valve body at both ends to rotate Within the housing in fixed spaced relationship to the interior walls thereof. In this connection, particular attention is directed to FIG. 3 in which it will be noted that the inner end of the valve body is provided with a tang 33 which is designed to fit into a recess 34 in the end of the crankshaft (FIG. 4). The tang is offset from the center as is the recess in the crankshaft. This insures proper assembly of the valve for correct timing as the valve body and housing can only be assembled to the motor housing when the tang is properly fitted in the recess. The tank fits into the bearing 36 in the motor housing with the opposite end edges of the tang in contact with the bearing and thus journalled for rotation, at the same time being held against radial displacement.

At the opposite end of the valve body there is provided a bearing 37 fitted into a recess 38 on the outer face of the valve housing and held in place by means of the outer face or ring 35 serving as a clamp securing only the outer ring of the bearing in place. The outer face is open in the center to provide free air discharge from the center of the valve housing.

The outer bearing serves to mount the valve body rigidly and prevent any radial movement and also hold it in fixed spaced relationship to the interior of the valve housing. This is very important consideration because it obviates the necessity for a bearing surface between the valve and housing. This in turn does away with the need for lubrication and, even more important, makes possible completely free communication between the ports in the valve and the cores of the valve housing. This is to be distinguished from prior structures which employ a pressed-in bushing extending throughout the length of the valve housing and having only intermittent openings providing communication with the air passages and plenum spaces of the housing. Elimination of this bushing and consequent interfering structures is made possible by the present invention with its combinaiton of casing and unique positive mounting thereof. Obviously, any need to replace worn bushings is also eliminated.

In the embodiment shown, the motor is a five cylinder structure and the valve housing is equipped with spaced mounting lugs 41 so that it may be selectively mounted in any one of five positions without changing the correct timing of air flow.

As is usual in structures of the type under discussion, air is admitted through port 42 or 43 depending upon whether forward or reverse motion is desired, the air supply being controlled by a suitable valve not shown.

The structure illustrated is adapted to be used with the crankshaft in either the horizontal position as shown or in vertical position. In horizontal use, splash type lubri- D caiton is provided by a splash plate 46 dipping into an oil reservoir.

In vertical use, pressured lubrication is employed and this is accomplished by lubricant passages 47, 48, 49 and 50 which, when not in use, can be easily plugged.

It will be seen from the foregoing that the present invention provides a structure which, because of its method of assembly enables the use of cast construction which in turn provides unobstructed air flows hence greater efficiency of operation and greatly reduced maintenance.

I claim:

1. In an air motor of the type including a motor and motor housing and a valve housing and valve body for supplying and exhausting air to and from the motor in timed sequence; the improved construction comprising bearing means at opposite ends of said valve body journalling the same for rotation within said valve housing in predetermined spaced-apart relationship with the walls thereof, a recess in one end of the crankshaft and offset from the center line thereof, a tank extending from one end of said valve body and ofiset from its center and adapted to fit into said recess to thereby fix said valve body in proper relationship to said crankshaft, and a clamp engaging the bearing at the opposite end of said valve body to secure it and said valve body Within said valve housing.

2. Construction according to preceding claim 1 in which the valve housing has air passage cores cast therein and is free from added structure thereby providing unobstructed air passages in said valve housing.

3. Construction according to preceding claim 2 in which said valve body is of unitary cast construction and air passage cores in said valve body are free from other structures thereby providing unobstructed air passage through said cores.

4. A structure according to preceding claim 3 in which an exhaust core is provided in said valve body axially of said body and communicates through an opening in the outer end of said valve housing, said opening being provided in said clamp engaging the bearing in which said valve body is journalled at said end.

5. A structure according to preceding claim 4 in which said hearing at said opposite end of said valve housing is a concentric ring bearing and said clamp engages only the outer of said concentric rings.

References Cited in the file of this patent UNITED STATES PATENTS 58,843 Lawther et a1 Oct. 16, 1886 2,372,523 Sinclair Mar. 27, 1945 2,945,479 Polio July 19, 1960

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