Patent Application
20060108446
The invention relates to a rotating sprinkler and, in particular, to a gear mechanism for rotating a portion of a sprinkler including cooperating portions that allow the mechanism to slip when rotation is resisted.
Currently, many types of sprinklers are known and utilized for distributing water to a desired area such as for watering plants, crops, and lawns. Some sprinklers are generally stationary and deliver water to a predetermined area dependent on the direction to which one or more outlets, such as nozzles, are pointed. Many sprinklers rely on a portion that moves relative to a stationary or fixed base portion so that the water is distributed to a particular area intermittently as water is distributed to a different area.
For instance, some sprinklers rotate back and forth so, at a particular moment, a first area receives a certain amount of water while another receives less and, at a subsequent moment the first area receives less than the other area. Other sprinklers include a portion that includes one or more nozzles that rotate or sweep over a particular area so that, again, different areas receive water intermittently.
One type of sprinkler is known as a motor driven sprinkler. Though there are many types of these, one example utilizes a turbine placed in the water stream. When the water stream strikes the turbine, the water forces the turbine to rotate in a predetermined direction based on vanes or vaned portions located on the turbine. The rotation of the turbine then drives a portion of the sprinkler including a nozzle in a rotary fashion. Thus, the rotation of the turbine effects the rotation of the nozzle for distributing water in a radial fashion, and portions of the surrounding area receives water for the period of time in which a spray or stream of the nozzle is directed at the surrounding area portions.
Many motor driven sprinklers are pop-up sprinklers. A pop-up sprinkler is a sprinkler having a case or housing that is generally stationary relative to the ground, and a riser that is in a retracted position when the sprinkler is shut off and is extended when the sprinkler is activated by turning the water on. The riser reciprocates between the retracted and extended position within an internal cavity of the housing so that a nozzle located on the riser is free to distribute water when the riser is extended, while typically being located within the housing when the riser is retracted.
In a motor driven pop-up sprinkler, the riser includes a sprinkler head portion that rotates relative to the riser when in the extended position and activated. The riser contains a motor assembly which is connected to the sprinkler head such that the sprinkler head is driven around by the motor assembly. In many cases, this motor assembly utilizes the described turbine.
In use, the sprinkler head rotates upon the activation of water. Therefore, the sprinkler head rotates as the riser is extending from the housing, when the sprinkler head is extended, and as the sprinkler head is retracting as the water flow is diminishing before the water flow ceases. During this time, particulate matter may come in contact with and between the sprinkler head and the riser body. Such particulate matter may cause binding between the sprinkler head and the riser body.
In addition, people often grab onto the extended and rotating sprinkler head. This may be done by a person who is trying to adjust a setting on the sprinkler head or is trying to examine the sprinkler head. At times, the sprinkler head is held by a person with negative intentions, such as a vandal.
In the event the sprinkler head is held stationary or bound so that it is prevented from rotating, damage can occur to the sprinkler head. The components utilized between the motor and the sprinkler head operate in a wet environment, and using steel, for example, is often not beneficial to the life of the sprinkler head. On the other hand, the plastic or polymer components often used are typically not strong enough to halt the rotation of the motor assembly, such as the turbine in the water stream. The force of the water is great enough that the turbine continues to spin, and the internal components between the turbine and the sprinkler head can strip each other.
Accordingly, there has been a need for an improved motor assembly for preventing damage to a sprinkler head when rotation is impeded.
Referring initially to
Where the rotation of the sprinkler head 16 is impeded by, for instance, a person holding the sprinkler head 16 stationary when the sprinkler 10 is activated, some portion of the motor assembly 18 must account for this stress. As the power delivered by the water stream on the turbine 70 is often too great for the turbine 70 to be stopped, the stress may be borne by components deforming, gears of the motor assembly 18 shearing teeth, or gears fixedly attached to axles slipping around the axles.
To provide a non-destructive, high-life cycle mechanism for responding to impedance of the rotation of the sprinkler head 16, the motor assembly 18 is provided with a slip-clutch assembly, as will be described below. In simple terms, the slip-clutch assembly replaces one of the components of the motor assembly with a pair of components which, when a threshold level of stress is experienced, slip relative to each other until the stress is relieved. Once the impedance ceases, the pair of components re-engage, and the sprinkler 10 continues to operate normally.
The housing 12 has a lower end 22 with an inlet 24 that is threaded to connect to a pipe (not shown) for delivering water to the sprinkler 10 from a water source (not shown). The sprinkler 10 may be one of a number of sprinklers 10 connected to an irrigation network for distributing water over a particular area and including controls for activating and shutting off the water supply.
In use, the sprinkler 10 is generally embedded into ground or soil for distributing water to an area surrounding the sprinkler 10, and an upper end 26 of the housing 12 is generally at ground or grade level. The sprinkler 10 has a retracted position, shown in
The housing 12 is generally cylindrical and defines a cavity 40 therein, and the riser 14 has a generally cylindrical outer surface 42. The riser 14 has a lower end 44 with an annular shoulder 46 extending thereabout. In a preferred embodiment, the shoulder 46 includes notches (not shown) for receiving ribs (not shown) located on an inner surface 48 of the housing 12. The notches cooperate with the ribs so that the riser 14 shifts generally linearly within the housing 12 between the retracted and extended positions.
The sprinkler 10 includes a bias member in the form of a coil spring 60 having an top coil 62 that contacts an inner shoulder 52 of the housing 12, as can be seen in
Activation of the water into the housing 12 causes the riser 14 to extend from the housing 12. The extended riser 14 allows the sprinkler head 16 and a nozzle 20 located thereon to be exposed, and water is directed in the direction of the nozzle 20. The upward shifting of the riser 14 in response to water pressure compresses the spring 60 between the riser shoulder 46 and the housing inner shoulder 52. When the water is shut off, the spring 60 directs the riser 14 to return to its original, retracted position.
During activation with the riser 14 extended, water flows through the riser 14 and causes the sprinkler head 16 to rotate. Broadly stated, the water flowing through the riser 14 drives the motor assembly 18 to rotate the sprinkler head 16. Specifically, the water strikes a turbine 70 located in a water passage 72 and connected to an axle 74. The turbine 70 rapidly rotates, such as in the order of 1890 RPMs. The axle 74 is connected to a first of a series of reduction gears of a gear assembly 80 of the motor assembly 18. The gear assembly 80 reduces the rotation so that the sprinkler head 16 rotates at approximately 1 RPM. This conversion or reduction results in a great deal of torque for driving the sprinkler head 16.
The sprinkler head 16 has a central axle 86 around which it rotates relative to the riser 14. The central axle 86 is generally cylindrical and communicates with the riser water passage 72 to receive water therethrough. The water is then delivered to the nozzle 20 for emission from the sprinkler head 16. As can be seen in
The sprinkler head 16 includes gearing 17 for engaging the motor assembly 18, as will be discussed below. In this manner, the motor assembly 18 converts the energy and force of the water striking the turbine 70 into rotational force and torque for rotating the sprinkler head 16.
Referring now to FIGS. 3 to 6, the motor assembly 18 of the sprinkler head 16 is depicted. The motor assembly 18 includes the turbine 70, a motor housing 90, the reduction gear assembly 80 located within the motor housing 90, and a direction assembly 94. The turbine 70 is connected to a lower portion 76 of the axle 74 such that the turbine 70 and axle 74 rotate together. An upper portion 78 of the axle 74 includes a pinion gear 79 that also rotates with the turbine 70 and axle 74.
The gear assembly 80 utilizes a plurality of paired gears 100 to communicate the rotation of the turbine 70 to the direction assembly 94. Each paired gear 100 has a larger lower portion 102 and an smaller upper portion 104 that rotate together freely around an axle 106. Both portions 102 and 104 of each paired gear 100 include gear teeth 105. However, the lower portion 102 has significantly more teeth 105 than the upper portion 104. Each paired gear 100 is mated and cooperates with another paired gear 100 so that the smaller upper portion 104 of a paired gear 100 cooperates with the larger lower portion 102 of a subsequent paired gear 100. In this manner, a single rotation of a larger lower portion 102 is effected by a plurality of rotations of a smaller upper portion 104.
The pinion gear 79 mates with a first paired gear 100a of the gear assembly 80. The pinion gear 79 is relatively small in comparison to the larger lower portion 102a of the first paired gear 100a and, accordingly, a plurality of rotations of the turbine 70 and pinion gear 79 is required to rotate the first paired gear 100a a single revolution. In this manner, the high revolutions per minute of the turbine 70, noted above, are reduced with a consequent increase in torque.
The gear assembly 80, as depicted, includes four paired gears 100a, 100b, 100c, and 100d. The paired gear 100d cooperates with a direction assembly pinion gear 110, as can be seen in
The direction assembly pinion gear 110 is non-rotationally secured to an axle 112 at an axle lower portion 114. An upper portion 117 of the axle 116 includes a distribution gear 118. The pinion gear 110 is received within an opening 120 in the motor housing 90 (see
The direction assembly 94 includes a rotation sub-assembly 122. The rotation sub-assembly 122 cooperates with the gearing 17 located on a portion of the sprinkler head 16 (see
The direction assembly 94 includes a lever 130 that is moved between two positions so as to adjust the position of the rotation sub-assembly 122 relative to the sprinkler head 16. In a first position, the first drive gear 124a is mated with the sprinkler head gearing 17 to effect rotation of the sprinkler head 16 in a first direction and the second drive gear 124b is disengaged from the sprinkler head gearing 17. In the second position, the first drive gear 124a is disengaged from the sprinkler head gearing 17 and the second drive gear 124b is engaged so that the sprinkler head 16 is rotated in a second, opposite direction.
As discussed above, the revolutions per minute of the turbine 70 are in the order of 1890 RPMs, and the sprinkler head 16 rotates at approximately 1 RPM. To respond to rotational impedance of the sprinkler head 16, the motor assembly 18 is provide with a slip-clutch assembly including a two or more components which are able to slip when a threshold level of stress is experienced and re-engage once the impedance is removed.
The slip-clutch assembly may be incorporated into any of the gears of the motor assembly 18. However, the further down-line from the turbine 70 the slip-clutch assembly is located, the greater its efficacy. For instance, if the slip-clutch assembly were incorporated into pinion 79 connected to the turbine 70, a single revolution prevented by a stationary sprinkler head 16 would require the pinion 79 to slip enough times to provide for approximately 1890 revolutions of the turbine 70. In contrast, if the slip-clutch assembly were incorporated at a subsequent gear in the motor assembly 18, the slips required for a missed rotation of the sprinkler head 16 would be reduced by the amount that the rotations had been reduced by the motor assembly rotation reduction.
In the preferred embodiment, the fourth paired gear 100d is provided as a slip-clutch assembly 150, as depicted in
The sleeve gear 154 includes a generally annular ring 160 and an annular top plate portion 162. An external surface 163 of the ring 160 includes gear teeth 105 corresponding to the gear teeth of lower portion 102 of a paired gear 100. The plate portion 162 includes a central opening 164 that is circular and has a center co-axial with the sleeve gear 154. Within the ring 160 is a cavity 166, and the ratchet gear 152 is received within the cavity 166 and through the opening 164, as will be discussed below.
An internal surface 168 of the ring 160 is stepped to form an upper portion 170 and a lower portion 172. The upper portion 170 has inwardly extending ridges or ratchet teeth 174 formed within the ring 160 evenly spaced around and theron. The ratchet teeth 174 define peaks 176 and troughs 178 for receiving portions of the ratchet gear 152, as will be discussed. The lower portion 172 is relatively smooth and has a diameter equal to that of the troughs 178 of the upper portion 170. Accordingly, a radially extending shoulder 179 is formed between the upper and lower portions 170, 172.
The ratchet gear 152 includes a central portion 180 that is generally cylindrical. The central portion 180 has an upper portion 182 including teeth 105 corresponding to gear teeth of the upper portion 104 of a paired gear 100.
The central portion 180 further has an intermediate portion 184 that includes a protruding circumferential rib 186 located a short distance below the geared upper portion 182. To assemble the slip-clutch assembly 150, the upper portion 182 is inserted into the opening 164 of the sleeve gear 150. The intermediate portion 184 is sized so as to closely match the diameter of the opening 164 while permitting rotation relative thereto. The protruding rib 186 is larger than the size of the intermediate portion 184, and consequently requires being forced through the opening 164 to secure the ratchet gear 152 with the sleeve gear 154.
The ratchet gear central portion 180 also has a lower portion 190 which is located in the cavity 166 of the sleeve gear 150. The lower portion 190 includes a series of arms 192 extending outward from the central portion 180 for cooperating with the ratchet teeth 174 of the sleeve gear 152. During normal operation, the arms 192 are engaged with the ratchet teeth 174 of the sleeve gear 152. When stress on the slip-clutch assembly 150 reaches a predetermined threshold in a particular direction due to impedance of the rotation of the sprinkler head 16, the arms 192 deflect inward so that they slip over the sleeve gear ratchet teeth 174, thus preventing damage to the sprinkler motor assembly 18.
Each arm 192 has a number of portions. The arm 192 includes a branch portion 194 extending in a radial direction from a base 196 at the central portion 180, a leg portion 200 extending circumferentially from the branch portion 194, and a foot portion 202 extending co-linearly from the branch portion 194 and radially from the central portion 180. Each branch 194 is generally secured and, preferably, formed integral with the central portion 180.
In the event the arm 192 is deflected inward, it is preferred that the leg portion 200 principally deform. In this manner, the circumferentially extending leg 200 need only deform a small amount to disengage from the ratchet teeth 174. More specifically, each leg 200 has a toe 210 having a first surface 212 generally formed in plane that is skewed outward from the leg 200. With reference to
When stressed and torqued, gears will tend to deflect away from each other. This results in improper mating, higher stress, and oftentimes damage. Accordingly, it is desired to provide the ratchet gear 152 and sleeve gear 154 with cooperating structure to prevent the gears 152, 154 from tilting with respect to each other. Towards this end, the arm 192 is provided with the foot 202, as noted above. The foot 202 extends beyond the ratchet teeth 174 and to the lower portion 172 of the internal surface 168 of the sleeve gear ring 160. The foot 202 has a top surface 216 that abuts and slides against the shoulder 179 formed between the upper and lower portions 170, 172 of the ring internal surface 168, and has an end surface 218 that is slightly arcuate for abutting and sliding against the internal surface lower portion 170.
In this manner, the ratchet gear 152 and sleeve 154 are reinforced against any force between tending to cause a relative tilt therebetween. The combination of the radially extending branch 194 and foot 202 act as a spoke between the central portion 180 and the ring 160. In addition, the surface 216 and shoulder 179 cooperate so that any tilting would require the arms 192 to deflect downward.
As noted, it is preferred that the slip-clutch assembly 150 be provided as the fourth paired gear 100d. However, it should be noted that the greatest reduction ratio is experienced at the direction assembly pinion gear 110. Accordingly, the sprinkler 10 may alternatively be provided a slip-clutch assembly 250 as the direction assembly pinion gear 110.
Referring now to
The drive gear 252 includes an external surface 270 including gear teeth 105, as described above for the direction assembly pinion gear 110. The drive gear 252 is similar to the sleeve gear 154 in that it has an annular ring 272 including the external geared surface 270 and a bottom plate 274 including an annular central opening 276 co-axial with the drive gear 252 itself. The ring 272 and bottom plate 274 define a cavity 278 into which the slip gear 254 is received, and the axle 112 is received in the opening 276 and a clip 280 is secured around a lower portion 282 of the axle 112 for retaining the drive gear 252 thereon. In addition, the opening 276 has an inner surface 284 that acts as a bushing against the axle 112, and the bushing 284 combines with the clip 280 to retard relative tilting between the drive gear 252 and the axle 112.
The slip gear 254 and drive gear 252 are provided with cooperating structure that allows the slip gear 254 to slip relative to the drive gear 252 when stress due to an impedance of the sprinkler head 16 rotation is exceeded. Specifically, a number of fingers 266 depend downward from the top plate 264 and are received by structure 290 located within the cavity 278 of the drive gear 252. The structure 290 is generally a series of circumferential walls sections 292 located at a shoulder 293 formed between the ring 272 and the bottom plate 274 of the drive gear 252. However, each wall section 292 is separated from an adjacent wall section 292 by a short gap 294 into which the slip gear fingers 266 are received.
Each finger 266 is provided with side surfaces 298 that are set at an angle inward from the outer circumference of the slip gear top plate 264. It is preferable that the angle be between 15° and 90°. The fingers 266 mate with the wall sections 292 in the gaps 294 therebetween, and these side surfaces 298 mate with similarly configured side surfaces 300 formed on the wall sections 292.
Under normal conditions, rotation of the drive gear 252 is transmitted to the slip gear 254 by driving the wall section side surfaces 300 against the finger side surfaces 298. When stress exceeds a predetermined level, the angled surfaces 298, 300 cam against each other, thereby forcing the fingers 266 to deflect inward. In this manner, the slip gear 254 and drive gear 252 are able to slip and relative to each other. When the stress is relieved, the fingers 266 return to a position located in the gaps 294 between the wall sections 292 to re-engage the slip and drive gears 254, 252.
It should be noted that the slip-clutch assembly may allow the turbine 70 and other components of the motor assembly 18 to rotate independently of the sprinkler head 16, which includes allowing the rates of rotation under normal conditions to be varied due to the impedance. This is particularly true considering that the slip-clutch assemblies disclosed herein utilize either friction or interference for transmitting power therethrough. Because the components of the slip-clutch assemblies remain generally in contact, this friction or interference is not completely removed. In this manner, the slip-clutch assembly re-engages very soon, if not immediately, after the impedance falls below the predetermined threshold level.
While the invention has been described with respect to specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.
