Adjustable Cam And Adjusting Means Therefor

Abstract

An adjustable cam formed of a single piece injection molded part in which a plurality of narrow strips are joined at common ends by yieldable loops and are disposed side-by-side; the adjacent strips being relatively movable longitudinally within the limits of the connecting loops and forming cam elements at their ends opposite from the loops which may be displaced to define collectively an adjustable cam surface. An embodiment of the adjustable cam includes a lateral extension on each strip forming opposed cam elements, and the cam is arranged in a circle. A cam adjusting means, including cam adjusting rollers, is rotatably mounted within the circle, and pivotal about a transverse axis so that by turning and pivoting the adjusting means, the cam strips are moved longitudinally to change the contour of the cam.

Description

BACKGROUND OF THE INVENTION

Cams are widely used to obtain predetermined motions. While it is often the case that it would be desirable to adjust or change the cam contour, usually this cannot be done; or, only at prohibitive expense. An example of the need for such a cam is found in the art of rotary sprinklers; that is, it is often desirable to arrange a sprinkler to cover other than a circular area. Fixed cams are used to control the angular position of a nozzle or to move a deflector into the path of the stream to produce, for example, an essentially square spray pattern. Often the area to be covered is irregular and sufficiently unique that it would be impractical and much too expensive to predetermine the cam shape capable of producing the desired irregular spray pattern. Also, as the plants grow, changes in the spray pattern may be required.

SUMMARY OF THE INVENTION

This invention is directed to an adjustable cam and adjusting means therefore and is summarized in the following objects:

First, to provide an adjustable cam wherein a series of relatively narrow strips are disposed in mutually contacting relation and form at their corresponding ends a series of narrow cam elements, the strips being relatively movable longitudinally so that the cam elements may be moved to define collectively a variable cam surface.

Second, to provide an adjustable cam, as indicated in the preceding object, which may be injection molded in one piece at a nominal cost with the cam strips disposed in radial relation and joined at their radially inner ends by yieldable connecting loops, the strips being movable from their molded positions into mutually contacting linear relation or circular relation.

Third, to provide an adjustable cam, as indicated in the preceding objects, wherein each strip includes a laterally directed portion forming opposing cam elements.

Fourth, to provide an adjustable cam and adjusting means therefore wherein the adjusting means also includes cam rollers and includes a manually engageable handle for manipulating the rollers to change the cam contour.

Fifth, to provide an adjustable cam and adjusting means therefore which is particularly adapted for use in conjunction with a rotary sprinkler whereby the pattern may be varied to distribute the water in various predetermined irregular patterns.

Sixth, to provide a sprinkler, as indicated in the preceding object, which incorporates a valve whereby the volume of water output may be varied by adjustment of the pattern control cam.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged fragmentary view of the cam structure, shown in the form in which it is injection molded.

FIG. 2 is a sectional view, taken through 2--2 of FIG. 5, showing one of the cam strips.

FIG. 3 is a fragmentary top view, at a reduced scale, showing the cam structure in its operating condition.

FIG. 4 is a fragmentary bottom view thereof.

FIG. 5 is an enlarged fragmentary view, taken from 5--5 of FIG. 3, showing the outer side of the cam structure as assemblied for operation.

FIG. 6 is a fragmentary side view, showing a modified form of the cam structure, as it appears upon being injection molded.

FIG. 7 is a fragmentary side view, showing the modified cam assembled for operation.

FIG. 8 is a sectional view, taken through 8--8 of FIG. 7.

FIG. 9 is a fragmentary plan view of the modified cam.

FIG. 10 is a longitudinal sectional view of a rotary sprinkler which utilizes the cam structure, the sprinkler being shown in the position for maximum water trajectory.

FIG. 11 is a similar longitudinal sectional view, but showing the parts arranged for minimum water trajectory.

FIG. 12 is a transverse sectional view, taken through 12--12 of FIG. 10.

FIG. 13 is a fragmentary longitudinal sectional view, taken through 13--13 of FIG. 10.

Reference is first directed to the cam structure shown in FIGS. 1 through 5. The cam structure 1 is injection molded as a single piece and includes a plurality of cam strips 2, which in their initial or molded position extend radially from a common center. The radially inner ends of the cam strips are joined by connecting loops 3. The walls of the loops are substantially thinner than the thickness of the cam strips and the width of the connecting loops are substantially less than the width of the cam strips. As a consequence, the cam strips can be manipulated from the initial condition shown in FIG. 1 to a condition in which the cam strips are formed into a cylinder with their major dimension extending axially. The sides of each cam strip taper so that when the cam strips are arranged to form a cylinder, their sides are in mutual contact. When in their cylindrical condition, as indicated in FIGS. 3 and 4, the connecting loops permit limited relative longitudinal movement of the cam strips.

In order to hold the cam strips in their cylindrical condition, each cam strip is provided with a cross channel 4. Collectively, the cross channels form an annular groove which receives a retaining band 5 of elastomeric material.

At its axial end, opposite from the connecting loop 3, each cam strip is provided with a lateral extension 6 from its edge opposite from the cross channel 4. The lateral extension forms at its upper edge an upper or axially outer cam element 7, and at its lower edge, a lower or axially inner cam element 8. The cam elements 7 continue across the upper ends of the cam strips.

The radially inner edges of the cam strips are provided with rudimentary serrations 9 so that when the cam strips are pressed radially inward against a cylindrical member by the constricting force of the retaining band 5, the cam strips tend to be held frictionally in place. However, they may be forced axially with respect to each other a limited distance. That is, the cam elements 7 and 8 form annular cam tracks which may be varied in contour by applying axial force upward or downward until the desired cam track contour is attained, as will be described in more detail hereinafter.

Reference is now directed to FIGS. 6 through 9, which illustrate a cam structure 10, which differs from the cam structure 1 only in that its cam strips 2 are not tapered and are initially cast in parallel relation, as indicated in FIG. 6, so that they may be pressed together, as indicated in FIG. 7, to form a lineal as distinguished from a circular cam. In this case, the cam strips are held by clamping bars 11 and spring loaded clamping pins or fasteners 12, as shown in FIG. 9.

Of the many applications for an adjustable cam structure, particularly of the cylindrical type, a rotating sprinkler offers a prime example. The application of the adjustable cam structure is therefore illustrated in conjunction with the sprinkler, shown in FIGS. 10 through 13.

The sprinkler here illustrated includes an outer housing 13, having a base portion 14 and an outer cylindrical sleeve 15. Mounted within the outer housing 13 is an inner or motor housing 16 which is cylindrical and includes a flange 17 for attachment to the periphery of the base portion 14 of the housing 13 by means of screws 18.

The inner and outer housings define a cylindrical cam receiving cavity 19. The cavity 19 receives the cam strips 2 and their connecting loops 3 with the extensions 6 extending radially inward over the upper end of the motor housing 16.

Clamped between the flanged lower end of the motor housing 16 and the base portion 14, by its periphery, is a swirl plate 20. Formed below the swirl plate in the base portion 14 is an inlet cavity 21 connected to an inlet passage 22. Formed above the swirl plate 20 is a motor cavity 23. The peripheral portion of the swirl plate 20 is provided with helically directed swirl slots 24.

The upper end of the motor cavity 23 is closed by a wall 25, having a bearing 26 therein. A corresponding bearing 27 is provided in the swirl plate 20. Journaled by the bearings 26 and 27 is a tubular rotor stem 28.

Within the motor cavity, the rotor stem is provided with a thrust flange 29. Thrust washers 30 are provided between the flange 29 and the wall 25.

The rotor stem 28 is provided with triangular impact lobes 31 and is provided with one or more side ports 32. Surrounding the impact lobes 31 is a drive ring 33 having four sides.

The motor construction thus far described is not, per se, part of the present invention and is merely shown and described to illustrate a means of accomplishing rotation. A motor of this type is disclosed in U.S. Pat. No. 3,315,898, issued Apr. 25, 1967.

The upper end of the rotor stem 28 receives a nozzle 34, which includes a vertical portion 35 and an angularly directed portion 36. Extending upwardly from the vertical portion 35 is a guide boss 37, having a small bore which receives a rod 38 extending downwardly through the rotor stem 28 and provided at its lower end with a valve head 39, which cooperates with a valve seat 40 provided at the lower end of the rotor stem 28. A spring 41 urges the rod 38 upwardly and the valve head 39 away from its valve seat 40. In actual operation, the valve head does not close against the valve seat 40.

The vertical portion 35 of the nozzle is provided with diametrically disposed lower pivot lugs 42 which pivotally support a first pivot frame 43. The frame 43 includes a radially directed yoke 44 on which is mounted an inner cam follower wheel 45 for engagement with the lower or inner cam elements 8.

The frame 43 also includes an upwardly directed yoke 46 which overlies the upper end of the rod 38 and is provided with a cam 47, adapted to cause axial movement of the rod on pivotal movement of the frame 43. A handle 48 extends from the pivot frame 43.

The vertical portion 35 of the nozzle is also provided with an upper set of diametrically disposed pivot lugs 49 which pivot a second pivot frame 50. The frame 50 includes a radial portion 51, having an outer cam follower wheel 52 which engages the upper or axially outer cam elements 7.

The second pivot frame 50 also includes a deflector tongue 53 which extends over the angularly directed portion 36 of the nozzle to a point beyond the discharge end of the nozzle. The tongue 53 is provided with a clearance slot 54 for the rod 38. The second pivot frame 50 is provided with a spring cup 55 which receives a spring 56 for yieldable engagement with the upwardly directed yoke 46 of the first pivot frame 43 so that the cam follower wheels are urged towards each other.

The cam structure and the rotary sprinkler cooperate as follows:

Before the sprinkler is operated, it is rotated manually and the handle 48 is manipulated to cause the cam followers to engage the cam elements 7 and 8. In the region surrounding the sprinkler, where it is expected that maximum water trajectory will be needed, that portion of the cam track is depressed, as indicated in FIG. 10. In the region where it is expected that minimal water will be required, the handle is tilted so that the cam followers raise the corresponding portion of the cam track, as indicated in FIG. 11.

Then, with the sprinkler in operation, the handle 48 is manipulated to cause the trajectory of the water stream to increase or decrease according to the particular spray pattern desired. Control of the water is not limited merely to its trajectory, but as the trajectory is reduced, the volume of water is reduced by reason of adjustment of the valve formed by the valve head 39 and valve seat 40. If the trajectory is short, the area to be covered is less and therefore less water is required. As a consequence, uniform water distribution is attained even though the area to be irrigated is irregular.

In order to have sufficient friction, the radially inner sides of the cam strips 2 are provided with serrations 2a, indicated partially in FIGS. 1 and 2.

While particular embodiments of this invention have been shown and described, it is not intended to limit the same to the details of the constructions set forth, but instead, the invention embraces such changes, modifications and equivalents of the various parts and their relationships as come within the purview of the appended claims.

Claims

I claim:

1. An adjustable cam comprising:

a. a plurality of cam strips;

b. at least one cam element formed on each cam strip and facing longitudinally with respect to the strip;

c. and a plurality of loops integrally connecting the strips to permit disposition of the strips and the cam elements in side-by-side contact, said loops permitting limited longitudinal displacement of the strips to effect corresponding relatively displacement of the cam elements;

d. said cam elements defining collectively a cam track of variable contour.

2. An adjustable cam, as defined in claim 1, wherein:

a. the cam strips define a cylinder, the connecting loops are located at one axial end of the cylinder, and the cam elements extend radially to form a circular cam track.

3. An adjustable cam, as defined in claim 1, wherein:

a. the strips are disposed in parallel relation and the cam elements form a linear cam track.

4. An adjustable cam, as defined in claim 1, wherein:

a. each cam strip is provided with a lateral extension and the axially facing edges thereof have opposing cam elements.

5. An adjustable cam, as defined in claim 2, wherein:

a. each cam strip is provided with a radial extension and the axially facing edges thereof have opposed cam elements defining a pair of cam tracks.

6. An adjustable cam, as defined in claim 1, wherein:

a. the cam strips are initially disposed in radial relation with the cam elements extending axially and the connecting loops at the radially inner ends of the strips;

b. the loops being relatively narrow to permit the strips to be turned from a radial direction to an axial direction, and whereby the cam elements are disposed in a radial direction.

7. An adjustable cam comprising:

a. a plurality of cam strips of wedge shaped cross-section and arranged, when placed side-by-side, to form longitudinally directed segments of a cylinder, the cam strips being relatively slidable axially with respect to the cylinder;

b. a pair of axially directed opposed cam elements carried by each cam strip, the cam elements forming collectively a pair of opposed circular cam tracks;

c. and means for yieldably retaining the cam strips in side-by-side contact, said means permitting relative axial displacement of the cam strips to effect change in the contour of the cam tracks.