SELF-ADJUSTING ROTARY-ARM IRRIGATION SPRINKLER

Abstract: A self-adjusting rotary-arm irrigation sprinkler comprises an intermediate piece (8) between the propulsion tube (1) and rotary arm (13), which supports the rotary arm and whose position is adjustable in height relative to the propulsion tube by means connected to the propulsion tube.

Description: This invention relates to irrigation sprinkler devices of the so called rotary arm type. The US-A-3580507 discloses a rotary arm irrigation sprinkler comprising a propulsion tube terminating in a nozzle and equipped with an arm oscillating about a horizontal axis, one end thereof being provided with a deflector spoon which move periodically into the water stream to produce reaction forces which cause oscillation of the arm as well as rotation of the propulsion tube. The known irrigators of the type above have some drawbacks due to the difficulty to adjust properly all the parameters involved in order to meet all the irrigation requirements. Practically it resulted easier the adjustment of a previous type of rotary irrigators, such as the type disclosed in the US-A-3019992. These latter have the arm bearing the deflector which oscillates about an axis orthogonal to the propulsion tube and lying in a vertical plane, and the rotation of the propulsion tube is due to the impact of the rotary arm while halting in its rest position. The sprinkles of this type have been initially used for smaller diameters of the nozzles, and have been recently improved for use with increasing thoughput of the delivered water. The more recent models of these sprinklers comprise an upwardly inclined propulsion tube which rotates on a practically vertical fixed feed column to cover a circular sector with the water jet delivered by it. The propulsion tube rotates by the action of an upper rotary arm which is swing-rotatable on a pin lying in the vertical plane and substantially orthogonal to the propulsion tube and carries at its front end at least one deflector device which interferes with the water jet. The water jet urges the arm to rotate away from its position sustantially parallel to the propulsion tube, while spring means return the arm into this position against a fixed stop, where it is struck by the jet, with a force which is sufficient to drag the entire propulsion tube by inertia, so that it rotates through a certain distance. The rotations of the propulsion tube induced in this manner are the main or outward rotations. If rotations are required in both directions, ie return rotations are also required further models are known, where the arm is made able to swing symmetrically about the propulsion tube by modifying only the position of the fixed stop on one or other side of the arm. In this case the speed of the outward and return rotations are the same. If the return speed is required to be different from, and generally greater than, the outward speed, the known art uses at least two deflector devices, of which at least one is fixed. In this case while the at least one fixed deflector damps the thrust of the arm during its outward rotation, it accelerates the thrust of the arm during its return rotation, so inducing a return speed greater than the outward speed. When the delivered water throughput increases above a certain level, the delivery nozzle of the propulsion tube acts too violently against the rotary arm deflector means, to irreparably compromise the proper regular operation of the sprinkler. This drawback is overcome in the known art by positioning parallel to the propulsion tube a secondary nozzle the purpose of which is merely to operate the rotary arm. In addition to the danger of the secondary nozzle clogging, this method results in a substantial reduction in the throw of the main jet, and operates properly only over a very small delivery pressure range, outside which the sprinkler operation is very irregular and entirely unsatisfactory. The present invention relate to the irrigators of the above mentioned type and, in a general way, of the type disclosed in US-A-3019992. The object of the present invention is to provide a rotary-arm irrigation sprinkler which is operated by the main sprinkler jet, is self-adjusting in order to ensure correct operation independent of throughput, and thus independent of the diameter of the nozzle fitted to the end of the propulsion tube and of the operating pressure, and can be further adjusted to vary the operating speed of the jet in order to adapt it to the nature of the terrain. This object is attained by a rotary arm irrigation sprinkler as specified in claim 1, whereby applying between the pin about which the rotary arm rotates and the rotary arm itself an intermediate piece which is adjustable at least in height and preferably in inclination, to in its turn adjust the height of the rotary arm. Particular embodiments of the invention are disclosed in the dependent claims. The position of said intermediate piece can be defined both by virtue of its bearing on the nozzle applied to the propulsion tube, and also by virtue of its engagement with adjustable support means operable from the outside, so that it can be positioned in height according to the diameter of the nozzle, and for one and the same nozzle can also be slightly swivelled in the vertical plane. The rotary arm assumes the same height position as the intermediate piece, so that that part of the deflector means which interferes with the jet is always the desired part . In addition, according to the invention whereas during the outward stroke the arm rotates freely in one direction but is restrained by a stop in the opposite direction, during the return stroke it rotates between two stops located a fixed distance apart and forming part of a single component. Furthermore, according to the invention the deflector comprises fins substantially parallel to the water flow, to give the deflector a slight downward thrust to keep it immersed in the jet and thus prevent annoying vibration of the arm. The merits and constructional and operational advantages of the invention will be more apparent from the detailed description of a preferred embodiment thereof given hereinafter by way of non-limiting example with reference to the accompanying drawings. Figure 1 is a partly sectional view of the end part of a self-adjusting irrigation sprinkler according to the invention. Figure 2 is a plan view of that shown in Figure 1. Figure 3 is a partial view of that shown in Figure 2. Figure 4 is a partial view of that shown in Figure 3 but in a different operating position. Figure 5 is a section on the line V-V of Figure 4. Figure 6 is a section an the line VI-VI of Figure 1. Figure 7 is a view In the direction VII of Figure 1. Figures 1 and 6 show the end part of a propulsion tube 1 to which a delivery nozzle 2 is applied. Immediately upstream of the delivery nozzle the tube 1 is provided upperly with a vertical pin 3, whereas in its underlying region (see Figure 6) it comprises a transverse sleeve 4 in which there is rotatably inserted a pin 5 provided at its projecting ends with two cams 6. The pin 5 can rotate under the control of a lever 7. On the pin 3 there is mounted an intermediate piece 8 which can slide vertically and rotate slightly about the pin 3. The piece 8 comprises two side walls 9 which descend about the sides of the tube 1 and are provided with two vertical opposing slots 10. The piece 8 terminates frontally with a vertical wall 11 provided at its centre with an inverted V-shaped seat 12. When mounted on its pin 3, the piece 8 assumes the position determined by the seat 12 bearing on the outer surface of the nozzle 2 and by the engagement of the cams 6 in the slots 10. The diameter of the nozzle 2 thus determines the height position of the piece 8, whereas the position of the cams 6, determined by the lever 7, sets the inclination of the piece 8 to the propulsion tube. Above the intermediate piece 8 there is mounted on the pin 3 the rotary arm 13, which rests an a projection 88 from the piece 8 by way of two antifriction washers 14. The arm 13 carries at its front a rotary deflector 15 and a fixed deflector 16, which are not described as they are of usual type, other than to note that the deflector 15 comprises parallel external fins 155 upward diverging from the axis of the nozzle in the direction of the water jet, the purpose of which is described hereinafter. At its rear end the arm 13 carries a stop finger 17, (See Figs. 2, 3 and 4), and a counterweight 18. A torsion spring 19 extending between the pin 3 and arm 13 elastically maintains this latter in the position A of Figure 2, the spring 19 being adjustable and covered by a cap 20. In the region to the rear of the pin 3 the propulsion tube 1 comprises (see Figure 5) two lateral lugs 21 through which is inserted the shaft 22 associated with the means, not shown as of usual type, which control the reversal of movement of the sprinkler. The shaft 22 has fixed to it, in the region above the tube 1, a lever 23 which can assume two positions (see Figures 2, 3 and 4) against two fixed upper stops 24 and 25 rigid with the tube 1. On the upper part of the shaft there is mounted in a freely rotatable manner a shaped blade 26, the sectional shape of which can be seen in Figures 2, 3 and 4 and which comprises a hub 261 and a step 262. The blade 26 is connected to the lever 23 by an off-centre spring 27 which causes it to undergo rotation in the opposite direction to the rotations of the lever 23 which are always delimited by the fixed upper stops 24 and 25. The device operates as follows. When a nozzle 2 of the required diameter has been fitted to the propulsion tube 1, the intermediate piece 8 assumes a position in terms of height which ensures that the deflectors 15 and 16 are suitably immersed in the delivered water jet. This thus ensures that the thrust which rotates the arm 13 away from the jet is balanced to thus determine acceptable amplitudes of arm swing. A finer adjustment of the extent of immersion of the deflector in the jet can be obtained by operating the lever 7, ie by varying the inclination of the intermediate piece 8 and thus the height of the arm 13. This type of adjustment enables the deflector immersion to be adjusted in accordance with the jet delivery pressure for any nozzle diameter. During the main or outward stroke the blade 26 is in the position shown in Figure 4. The finger 17 fixed to the rear of the arm 13 thus halts against the hub 261 of the blade 26, and the arm rotates freely in the other direction. The amplitude and frequency of the swing movements determine the speed of rotation of the sprinkler. It should he added that these two parameters depend on the extent of immersion of the deflector in the jet and on the tension of the return spring. During the return stroke the blade 26 is rotated into the position shown in Figures 2 and 3, and the finger 17 is constrained to rotate between the hub 261 and the step 262 of the blade 26. In both cases the fins 155 of the deflector 15 are always upward diverging from the axis of the nozzle in the direction of the water jet, to draw the deflector towards the jet, ie downwards, so eliminating any undesirable vibration of the rotary arm. It should also be noted that the embodiment shown is particularly simple and economical, but can be subjected to numerous modifications. For example the intermediate piece 8 could be a separate plate independently adjustable in height and inclination, and itself carrying the pin on which the rotary arm rotates. Thus the illustrated embodiment is non-limiting and numerous modifications and improvements can be made to the practical implementation of the invention but without leaving the scope of protection of the following claims.

Claims: A rotary arm irrigation sprinkler comprising an arm (13) mounted on a pin orthogonal to a propulsion tube (1) and lying in a vertical undergoing swinging rotation in a plane orthogonal to the pin and provided at its front with at least one deflector (15; 16) which interferes with the jet, and further provided with an adjustable spring (19) which urge it towards a position parallel to propulsion tube (1), there being provided rear means (261), (262) for arresting the rotation of the rotary arm (13), characterised by comprising an intermediate piece (8) between the propulsion tube (1) and rotary arm (13), which supports the rotary arm and rests close to the outlet of the nozzle (2) disposed at the end of the propulsion tube (1). A rotary arm irrigation sprinkler as claimed in claim 1, characterized in that the intermediate piece (8) consists of a plate, whose end overlying the nozzle (2) is provided with a frontal vertical wall (11) having an inverted V shaped seat (12) resting on the outer surface of the nozzle (2), and which has two lateral descending walls, lying on the opposite sides of the propulsion tube (1) and each having a vertical slot receiving cam means (6) angularly adjustable under control of a lever (7), there being provided at the center of the plate a projection (88) with a central hole through which the pin (3) projecting from the sprinkler propulsion tube (1) can be slackly inserted. A rotary arm irrigation sprinkler as claimed in claims 1 and 2, characterized in that the rotary arm (13) rests on the intermediate piece (8) by way of antifriction washers (14) and is mounted on the pin (3) projecting from the propulsion tube (1) through the intermediate piece (8). A rotary arm irrigation spinkler as claimed in claim 1, characterized in that the rotary arm (13) is mounted on the pin (3) projecting from said intermediate piece (8). A rotary arm irrigation sprinkler as claimed in claim 1, characterized in that the deflector (15) disposed at the end of the rotary arm (13) comprises parallel fins (155) which are inclined to and upward diverging from the axis the nozzle (2), in the direction of the water jet. A rotary arm irrigation sprinkler as claimed in claim 1 characterized in that to the rear end of the rotary arm (13) there is fixed a stop finger (17) which halts against both the hub (261) and the step (262) of an oscillating blade (26), or only against the hub (261) thereof, depending from the position of the blade (26).

Inventors: DRECHSEL, ARNO
Applicants: DRECHSEL, ARNO
Application year: 1988
Main classification: B05B3
IPC codes: B05B3