Rotary sprinklers

Abstract: A rotary sprinkler includes a rotor (210) rotatably mounted with respect to its nozzle and a retarding device having a first surface rotatable with the rotor, a second surface non-rotatable with respect to the nozzle (202), and a viscous liquid between the two surfaces. The first surface of the retarding device is a cavity (220) formed in the rotor, and the second surface of the retarding device is on a pin (222) non-rotatably mounted with respect to the nozzle and disposed within the cavity (220). The rotor further includes a cover (226) closing the cavity (220) and formed with an opening for receiving the pin (222), and a seal (228) carried by the cover (226) and including an annular sealing surface in contact with the pin (222) to seal the cavity, the annular surface of the seal being located so as to be continuously immersed in the viscous liquid in the cavity.

Description: The present invention relates to rotary sprinklers. A common form of rotary sprinkler includes a nozzle outputting a jet axially of the nozzle, and a rotor rotatably mounted with respect to the nozzle in alignment with the axial jet and having a surface formation impinged by the axial jet and effective to deflect the jet laterally of the nozzle and to rotate the rotor. Such rotary sprinklers, however, have a tendency to rotate at a high velocity, which decreases the effective range of the sprinkler. For this reason, such sprinklers have been provided with a retarding device having a viscous liquid for retarding the rotation of the rotor. US-A-Patent 4,660,766 (WO-A-8701620) and US-A-4,796,811 describe a rotary sprinkler, comprising a nozzle outputting a jet axially thereof, a rotor rotatably mounted with respect to the nozzle in alignment with the axial jet and having a surface formation impinged by the axial jet to deflect the jet laterally of the nozzle and to rotate the rotor, and a retarding device having a first surface rotatable with the rotor with respect to the nozzle, a second surface non-rotatable with respect to the nozzle, and a viscous liquid between said first and second surfaces. In the sprinklers described in both of the above patents, the surface rotatable with the rotor with respect to the nozzle is in the form of a shaft secured to the rotor, and the surface non-rotatable with respect to the nozzle is in the form of a cavity formed in a part of the rotary sprinkler fixed to the nozzle. An object of the present invention is to provide a rotary sprinkler of the foregoing type, but including an improved retarding device construction having advantages in several respects as will be described more particularly below. According to the present invention, there is provided a rotary sprinkler of the foregoing type, characterized in that said first surface of the retarding device is a cavity formed in a surface of the rotor opposite to that having said surface formation impinged by the axial jet, and said second surface of the retarding device is carried by a pin non-rotatably mounted with respect to said nozzle and disposed within said cavity; and in that said rotor further includes a cover closing said cavity and formed with an opening for receiving said pin, and a seal carried by said cover and including an annular sealing surface in contact with said pin to seal the cavity, said annular surface of the seal being located so as to be continuously immersed in the viscous liquid in said cavity. An important advantage provided by the foregoing features is that they enable sprinklers to be constructed more compactly than the previously-known sprinklers of this type. Thus, in the previously-known sprinklers (as described for example in the two above-cited patents), the cavity of the retarding device is formed in the part fixed to the nozzle, such as in the leg of a bridge fixed to the nozzle. This requires that part (e.g., the leg of the bridge) to be of sufficient thickness to accommodate the required height of the socket. In the present invention, since the rotor must be of a certain minimum height in order to perform its deflecting function, this required height of the rotor is exploited to form the socket for receiving the pin of the retarding device, thereby obviating the need to thicken the mounting member fixed to the nozzle for rotatably mounting the rotor. In fact, it has been found that a rotary sprinkler constructed in accordance with the foregoing features of the present invention enables the overall height of the sprinkler to be reduced by approximately 50% as compared to rotary sprinklers of the previously-known type for the same flow rate. Further features and advantages of the invention will be apparent from the description below. The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: Fig. 1 is a longitudinal sectional view illustrating one form of rotary sprinkler constructed in accordance with the prsent invention; Fig. 2 is an enlarged fragmentary view of Fig. 1; Figs. 3, 4 and 5 are enlarged sectional views along lines III--III, IV--IV and V--V, respectively, in Fig. 2; and Figs. 6 and 7 are longitudinal sectional views illustrating two additional rotary sprinklers constructed in accordance with the present invention. Fig. 1 illustrates a rotary sprinkler comprising a nozzle 202 of outer cylindrical configuration connectible to a source of pressurized water and formed with a through-going bore 204 for producing a jet parallel to the axis 206 of the nozzle. In the conventional manner of using the illustrated rotary sprinkler, nozzle 202 is mounted so that its axis 206 extends vertically. The illustrated sprinkler further includes a bridge 208 having a lower horizontal leg 208a secured to nozzle 202, a vertical leg 208b laterally of the nozzle, and an upper horizontal leg 208c spaced above the nozzle. Bridge 208 is used for rotatably mounting a rotor, generally designated 210, in axial alignment with respect to nozzle 202. For this purpose, the lower end of rotor 210 is formed with a socket 212 rotatable with respect to nozzle 202, and bridge leg 208c is also formed with a socket 214 for rotatably mounting the rotor. The two sockets 212 and 214 are in alignment with each other and also with the axis 206 of the nozzle bore 204. Socket 212 of rotor 210 floatingly mounts the rotor on nozzle 202, permitting the rotor to move axially, as well as rotatably, with respect to the nozzle. Thus, when the sprinkler is not operating, rotor 210 rests, by its own weight, against the upper face of nozzle 202 so as to close the nozzle bore 204 against the entry of insects, dirt or the like; and when the sprinkler is operating, the pressurized water discharged via bore 204 of the nozzle, raises the rotor 210 (as shown in Fig. 1), and rotates it about axis 206. The underface of rotor 210 is formed with a pair of channels or grooves 210a, 210b of curved configuration each extending through an arc of approxinmately 90°, such that the lower end of each channel is aligned with the nozzle bore 204, and the upper end of each channel extends substantially horizontally, or with a slight upward inclination to the horizontal. The underface of rotor 210 thus receives the water jet exiting axially from nozzle 202 and deflects it laterally of the nozzle, to thereby rotate the rotor and also to form two streams of water laterally of the sprinkler. As mentioned earlier, such rotary sprinklers tend to rotate very rapidly, thereby substantially decreasing the range of the sprinkler, and therefore it is known to provide retarding devices for retarding the rotation of the rotor. The rotary sprinkler illustrated in Fig. 1 includes a retarding device of the previously-mentioned viscous-liquid type but is of a novel construction and has advantages over the previously-known constructions. The retarding device included in the rotary sprinkler illustrated in Fig. 1 comprises a cavity 220 formed in the surface of the rotor 210 opposite to that having the channel formations 210a, 210b impinged by the axial jet. The retarding device further includes a pin 222 non-rotatably coupled to bridge leg 208c fixed with respect to nozzle 206. The lower end of pin 222 carries a skirt 224. Both the pin and its skirt are received within cavity 220 formed in the rotor 210. The cavity 220 is closed by a cover 226, which cover also carries a seal 228 in sealing relationship with respect to pin 222. Cavity 220 is filled with a viscous liquid which is effective to retard the rotation of rotor 210 with respect to pin 222, and thereby with respect to nozzle 202. As shown particularly in Fig. 3, socket 214 formed in bridge leg 208c is of non-circular cross-section, and the portion of pin 222 received within this socket is also of non-circular cross-section. Thus, pin 222 is prevented from rotating with respect to nozzle 202, but is permitted to move in the axial direction towards and away from the nozzle. Cavity 220 is formed with a central cylindrical section 220a serving as a bearing for the inner end 222a of pin 222, an outer cylindrical section 220b of substantially wider diameter, and a conical section 220C joining the two cylindrical sections 220a, 220b. Skirt 224 is formed with an inner section 224a fixed to the pin 222 and extending generally radially with respect to the pin, and an outer annular section 224b extending generally axially with respect to the pin. The inner section 224a is of conical configuration, corresponding to the conical configuration of cavity section 220c, and the outer annular section 224b of the skirt is of cylindrical configuration conforming to the cylindrical configuration of cavity section 220b. The inner conical section 224a of the skirt is perforated with a plurality of openings 224c, and the outer annular portion 224b of the skirt is formed with a plurality of axial slots 224d (Fig. 5), to permit the free flow of the viscous liquid within the cavity 220. Cover 226 closing cavity 220 is formed with a central opening 226a for freely receiving pin 222. The outer circumference of cover 226 is adapted to be attached with a snap-action fit to rotor 210. Rotor 210 is formed with an annular shoulder 210c at the upper end of the cavity 220, and with an annular rim 210d at its outer face. The two channel formations 210a, 210b of the rotor come to a juncture 210c coaxial with the jet axis 206. Cover 226 is further formed with a circular array of recesses 226b on its underface (Fig. 4) to define a plurality of radially-extending ribs 226c which engage the inner face of rotor 210 when the cover is snap-fitted thereto. The recesses 226b facilitate the initial filling of cavity 220 with the viscous liquid, and also refilling whenever that may be necessary, as will be described more particularly below. Seal 228 fixed to cover 226 is formed with a first conical section 228a attached to a complementary conical section 226d formed centrally of the cover, and with a second conical section 228b formed at its inner end with an annular sealing surface 228c in contact with the outer surface of pin 222. The sprinkler illustrated in Fig. 1 further includes a shield 230 fixed to pin 222 and overlying cover 226 as well as a portion of the rotor 210 to which the cover is attached. Shield 230 includes an inner section 230a of generally disc configuration, and an outer shroud 230b of cylindrical configuration so as to enclose the portion of rotor 210 to which the cover 226 is attached. Both the disc section 230a and the outer shroud 230b of shield 230 are closely spaced to the cover 226 and the portion of the rotor 210 to which the cover is attached, to define a labyrinth 232 obstructing the entry of dirt between the rotor 210 and the pin 222. The confronting faces of the shield 230, cover 226, and rotor 210 may be irregularly shaped, as shown particularly in Fig. 1, to enhance the so-formed labyrinth. The sprinkler illustrated in Figs. 1-5 is used in the following manner: First, the cavity 220 in rotor 210, when the rotor is removed from the sprinkler, may be filled with the viscous liquid. Pin 222, including its skirt 224, is then inserted into the cavity 220, and the cover 226 including its seal 228 is applied with a snap-fit over the outer end of the rotor 210. One end of pin 222, with the shield 230 then or previously fixed thereto, is passed through cover 226 and its seal 228 of the rotor 210, and the other end of pin 222 is received within socket 214 by bridge leg 208c, such that the underface of the rotor is in alignment with nozzle 202. When the cover 226 is snapped-over the outer end of rotor 210 to close the cavity 220 within the rotor, any excess of viscous liquid within the cavity is permitted to flow out through the openings defined by the recesses 226b in the cover 226. Such recesses thus facilitate the initial filling of the cavity 220 with the viscous liquid, and also any refilling which may be subsequently required. It will also be seen that the annular sealing surface 228c of the seal 228 is always immersed in the viscous liquid within the cavity. This is because the annular seal is at a low point in the cavity should the viscous liquid fail to completely fill the cavity. By thus assuring that the annular sealing surface 228c is always immersed in the viscous liquid, the sealing surface is prevented from drying out, and a low-friction seal is effected with respect to pin 222, thereby decreasing the wear on the seal and extending its useful life. When the sprinkler is not operating, rotor 210 drops by its own weight over nozzle 202, so that socket 212 at the lower face of the rotor obstructs the entry of dirt, insects, or the like during the non-operation of the sprinkler. As soon as the sprinkler is put into operation, the pressurized water exiting from nozzle 202 impinges against the lower face of rotor 210, thereby lifting the rotor, as shown in Fig 1. This lifting movement is permitted by the movement of pin 222 within socket 214 of the bridge leg 208c. The jet discharged from nozzle 202 is divided into two streams by the two curved channels 210a, 210b in the underface of rotor 210, which streams are deflected laterally of the sprinkler. The impingement of the jet from nozzle 202 on the underface of rotor 210 also rotates the rotor, so that the two streams of water deflected laterally of the sprinkler produce a 360° wetting pattern around the sprinkler. During this rotation of rotor 210, the viscous liquid within cavity 220, between the inner surfaces of the cavity rotating with the rotor and the surfaces of pin 222 and its skirt 224 disposed within the cavity which do not rotate with the rotor, applies a retarding force against the rotation of the rotor. This retarding force is effective to slow-down the rotation of rotor 210, and thereby to increase the range of the water distribution as compared to a sprinkler in which the rotation of the rotor is not retarded. As described earlier, by forming the cavity 220 for the viscous liquid in the rotor 210, rather than in a part fixed to the nozzle 202, the sprinkler can be constructed of significantly smaller size than heretofore possible for the same flow rates. This compactness in the construction of the illustrated sprinkler is further enhanced by the other structural features as described above, including the provision of the skirt 224 at the inner end of pin 222 and disposed within the cavity 220. As mentioned earlier, these constructional features enable the sprinkler to be reduced in size by about 50% as compared to the previously-known viscous liquid speed-reducers, for the same flow rates. Fig. 6 illustrates a rotary sprinkler of basically the same construction as described above with respect to Figs. 1-5, except that the two channel formations, indicated at 310a and 310b in the rotor 310, do not come to a juncture (shown at 210e in Fig. 1), coaxial with respect to the axis 206 of the jet, but rather come to a juncture shown at 310e in Fig. 6 which is eccentric with respect to the axis 306 of the jet from nozzle 302. Such a construction has been found to provide a more uniform distribution of the water around the sprinkler. Fig. 7 illustrates a further variation wherein the rotor, therein designated 410, is formed with a single channel 410a impinged by the jet discharged from the nozzle 402 so as to produce a single stream of water laterally of the sprinkler and rotating with the rotation of the rotor. In all other respects, the sprinklers illustrated in Figs. 6 and 7 are of the same construction, and operate in the same manner, as described above with respect to Figs. 1-5. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: A rotary sprinkler, comprising: a nozzle (202; 302; 402) outputting a jet axially thereof; a rotor (210; 310; 410) rotatably mounted with respect to the nozzle in alignment with the axial jet and having a surface formation (210a, 210b; 310a, 310b; 410a) impinged by the axial jet to deflect the jet laterally of the nozzle and to rotate the rotor; and a retarding device having a first surface (220) rotatable with the rotor (210) with respect to the nozzle (202), a second surface (224) non-rotatable with respect to the nozzle, and a viscous liquid between said first and second surfaces; characterized in that said first surface of the retarding device is a cavity (220) formed in a surface of the rotor (210) opposite to that having said surface formation impinged by the axial jet, and said second surface (224) of the retarding device is carried by a pin (222) non-rotatably mounted with respect to said nozzle and disposed within said cavity; and in that said rotor further includes a cover (226) closing said cavity and formed with an opening for receiving said pin, and a seal (228) carried by said cover and including an annular sealing surface in contact with said pin to seal the cavity, said annular surface of the seal being located so as to be continuously immersed in the viscous liquid in said cavity. The rotary sprinkler according to Claim 1, wherein said cavity (220) includes a substantially cylindrical section (220b), and said pin (222) includes a skirt (224) disposed within said substantially cylindrical section of the cavity and immersed in the viscous liquid in the cavity. The rotary sprinkler according to Claim 2, wherein said skirt (224) is formed with an inner section (224a) fixed to the pin (222) and extending generally radially with respect thereto, and an outer annular section (224b) extending generally axially with respect to the pin. The rotary sprinkler according to Claim 3, wherein said inner section (224a) of the skirt (224) is formed with a plurality of openings (224c) to permit the free flow of the viscous liquid therethrough. The rotary sprinkler according to either of Claims 3 or 4, wherein one surface (220c) of said cavity (220) is of conical configuration, and said inner section (224a) of the skirt (224) is adjacent to, and of the same conical configuration as, said one surface (220c) of the cavity. The rotary sprinkler according to any one of Claims 1-5, wherein said seal (228) includes a first section (228a) attached to said cover (226), and a second section (228b) formed with said annular sealing surface in contact with said pin (222). The rotary sprinkler according to Claim 6, wherein said first section (228a) of the seal (228) is formed with a conical socket for receiving a complementary conical stem (226d) formed in said cover (226). The rotary sprinkler according to Claim 7, wherein said pin (222) includes a shield (230) fixed to and overlying said cover and the portion of the rotor to which the cover is attached. The rotary sprinkler according to Claim 8, wherein said shield (230) includes a shroud (230b) enclosing the portion of the rotor to which the cover is attached, the inner surface of said shield and its shroud being closely spaced to the cover and the portion of the rotor to which the cover is attached to define a labyrinth (232) obstructing the entry of dirt between the rotor and the pin. The rotary sprinkler according to any one of Claims 1-9, further including a pin-mounting member (208c) fixed to said nozzle, said pin-mounting member being formed with a socket (214) for receiving said pin (222), both said latter socket and the portion of said pin received therein being of non-circular cross-section so as to prevent rotation of the pin with respect to the nozzle, but to permit movement of the pin axially of the nozzle.

Inventors: COHEN AMIR, COHEN, AMIR
Applicants: AGROTEAM CONSULTANTS LTD, PLASTRO GVAT, AGROTEAM CONSULTANTS LTD.
Application year: 1990
Main classification: B05B3
IPC codes: B05B3