Abstract:
A switch for use in dairies with reduced cost, improved reliability, and minimal hysteresis. The switch includes a paddle having a first end and a second end. The second end is contacted by another device or animal, and the first end is thereby moved relative to an inductive sensor.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to switches used in a dairy environment, and more particularly to flexible paddle switches for use in dairies that are reliable and relatively inexpensive. 
         [0002]    Throughout dairies, motion detection, contact and other types of switches are used to sense movement and the presence of animals and machinery. Near-constant usage and the harsh conditions of a dairy cause switches to break and malfunction. Replacing switches can cause equipment downtime, high maintenance costs, and reduced automation in dairies. 
         [0003]    Standard switches include mechanical and electrical components that must be shielded from dairy conditions, and repaired or replaced regularly. Even when such components remain operable, their reliability can be compromised by dirt and debris. 
         [0004]    There is a need for more efficient and reliable switches with reduced manufacturing, installation, and maintenance costs. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention is directed to a simple and reliable switch for use on machinery and for detection of cow movement. The switch is preferably a paddle switch that is mounted on a moving piece of equipment or on a fixed structure in a dairy. The switch includes a paddle made of a material such as polyurethane sheet stock or other suitable material or combination of materials. The switch paddle has a mounting portion about which the paddle pivots, and which is preferably mounted at a location that is offset from the paddle midpoint. The mounting is secure enough to permit the rest of the switch paddle to pivot about a pivot line when contacted by other equipment, animals or structures. 
         [0006]    The switch has a first end and a second end, and a metal clip is joined to the first end of the switch so that an inductive sensor can sense the position of the paddle. When the second end of the switch moves, the first end and metallic clip also move and are detected by the inductive sensor. The inductive sensor then transmits a signal via wires, wireless, or other conduit to a signal receiving device. The switch can be single acting or double acting to sense movement in one or two directions, respectively, or to send signals to multiple receivers. 
         [0007]    The switch paddle may have a uniform thickness. The switch paddle may also have different heights at various portions along its length. For example, the mounting portion may have a greater height than the height of the paddle first and/or second ends. The first end may have a height that is greater than the height of the second end. These variations in height enable the first and second end to pivot to different degrees from one another and enable the mounting portion or adjacent areas to act as a “living hinge” that permits resilient bending without the need for additional mechanical components. 
         [0008]    The present invention is directed to a switch that: has few moving parts; is resistant to being fouled by dirt, debris, and water; and is relatively inexpensive to make, install, and maintain. 
         [0009]    In addition, a switch in accordance with the present invention reduces the possibility of “false triggers” and has minimal hysteresis. Instead, the dairy switch reliably detects movement, and responds and resets quickly and reliably. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a side view of a switch in accordance with the present invention; 
           [0011]      FIG. 2  is a perspective view of the switch of  FIG. 1  mounted on a support structure; 
           [0012]      FIG. 3  is a partial perspective view of a rotary milking parlor with a switch in accordance with the present invention; and 
           [0013]      FIG. 4  is an end view of a cow counting gate incorporating a switch in accordance with the present invention. 
           [0014]      FIG. 5  is a side view of a switch paddle in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0015]    In the following detailed description of the preferred embodiments, the same reference numeral will be used to identify the same element in each of the figures. As illustrated in  FIGS. 1 and 2 , there is a switch  20  in accordance with the present invention. 
         [0016]    The switch  20  includes: a paddle  22  having a first end  24 , a second end  26 , a mounting portion  28 , and a metallic clip  30  joined to the first end  24 , and an inductive sensor  32 . 
         [0017]    The paddle  22  mounting portion  28  is disposed between the first end  24  and the second end  26 . The first end  24  and the second end  26  pivot about the mounting portion  28  when the switch  20  is being activated. The paddle  22  is preferably made of a material such as polyurethane that is able to withstand dairy conditions, is inexpensive, and can be formed into a variety of useful shapes. The paddle  22  can be any shape, but a shape in which the first end  24  is shorter than the second end  26  is preferred so that the first end  24  is responsive to even slight movements of the second end  26 . A more detailed description of preferred paddle  22  dimensions is provided below. 
         [0018]    The second end  26  can be any shape and length, and will be sized according to its application. For example, when the switch  20  is used to detect relative movements of machinery, the second end  26  need only be long enough to span the distance between adjacent mechanical components. When used to detect cow movement, for example, the second end  26  can extend across as much of a gate or alley as necessary to ensure contact by cows passing through. 
         [0019]    As stated above, the first end  24  and the second end  26  are separated by the mounting portion  28 . The mounting portion  28  can be of any shape that is suitable for mounting in any given application. The mounting portion  28  can be made entirely of the same material as the rest of the paddle  22  as in the illustrated embodiment or include other materials such as mounting plates  34 . The mounting plates  34  are metal in the preferred embodiment and are joined to the mounting portion  28  with screws  36  or other suitable connectors. Other mounting plate  34  materials could be used. The mounting plates  34  include holes  38  through which bolts, screws, nails or other switch mount connectors  40  ( FIG. 2 ) secure the switch  20  to a structure  44 . Alternatively, the mounting plates  34  can be welded or otherwise secured to a structure  44 . 
         [0020]    The mounting plates  34  are typically not flexible while the paddle  22  is flexible to obviate the need for hinges or other mechanical or spring-loaded devices. This arrangement acts like a “living hinge” to give the desired flexibility and performance. 
         [0021]      FIG. 5  illustrates dimensions and relative dimensions for a paddle  22  in accordance with the present invention. Optimal dimensions will depend upon the specific application to which the paddle  22  will be put, but the following general description will enable one skilled in the art to make and use the present invention. 
         [0022]    Preferably, the thickness of the material should be adequate to give the paddle  22  adequate rigidity over its span. Overall dimensions must also accommodate material removed for bore holes and possibly material gradually lost to wear and tear. Preferably, the thickness of all portions of the paddle  22  is substantially uniform throughout, but varying thicknesses could be used to modify performance or reduce weight, for example. 
         [0023]    As stated above, the paddle  22  includes a first end  24 , a second end  26 , and a mounting portion  28 . The first end  24  may include an end portion  90  and neck portion  92 . The neck portion  92  has a height dimension A. The end portion  90  size may be adjusted to suit the specific sensor and bracket needs. 
         [0024]    The mounting portion  28  has a width J and a height dimension B between mounting holes  94 . The paddle  22  end portions pivot about an axis L. Width J of the transition portion  28  is selected to ensure that the pivot axis L will withstand repetitious movement and be resilient enough to return the paddle  22  to a home (unpivoted) position. Transition fillets  98  are used between the mounting portion  28  and the second end portion  26  to reduce stress concentrations and avoid possible sharp corners on which animals or machinery could catch. The second end portion  26  in the illustrated embodiment has a uniform height of dimension C, but varying heights could be used. 
         [0025]    Preferably, the mounting portion  28  has a height dimension B that is larger than the second end  26  height dimension C so that rotation about axis L will be translated to a relatively small amount of pivoting movement of the paddle first end  24 . This differential in heights causes the axis L to behave as a “living hinge” that flexes without the aid of separate mechanical hinges or other mechanical components, while simultaneously withstanding harsh dairy use. 
         [0026]    The differential height also translates pivoting movement in varying degrees between the second end  26  and the first end  24 . Thus, the amount of pivoting movement desired in the first end  24  can be selected by varying the relative height dimensions of the paddle  22  parts. The larger the mounting portion  28  dimension B relative to the second end  26  dimension C the greater amount of pivoting that takes place in the first end  24 . If dimension B is too small relative to dimension C, stress fractures can occur in the fillet  98 . If dimension B is too large relative to dimension C, the second end  26  may not return reliably back to its home (straightened) position. Preferably, dimension B is about one inch to about ten inches greater in height than dimension C. 
         [0027]    Dimension A of the first end  24  is preferably smaller than dimension C to transmit pivoting movement from the second end  26  to the first end  24 . In general, the second end  26  may pivot as much as about 180 degrees in either direction about the axis L, while the first end  24  will pivot in the opposite direction, but typically only up to about forty-five degrees. It may go up to 90 degrees in either direction, depending on the other dimensions. 
         [0028]    If desired, the first end  24  dimension A could be smaller than the second end  26  dimension C, to cause the first end  24  to pivot a greater amount than the second end  26 . 
         [0029]    The flexibility of the paddle  22  depends on material properties as well. Preferably, the material has a Durometer A95, but others could be used. 
         [0030]    Another manner of determining paddle dimensions is the use of ratios for the various ends and mounting portions. The following chart lists unit lengths that are useful in the present invention. 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
               
               
                 Movement of 
                 Movement of 
                   
                   
               
               
                 Location F from 
                 Location G from 
                 Length 
               
               
                 Center (outside 
                 Center (as a result 
                 of Location 
                 Length of 
               
               
                 force pushing or 
                 of an outside force 
                 G to axis at 
                 Location F to 
               
               
                 pulling location) 
                 at Location F). 
                 Location L 
                 axis at Location L 
               
               
                   
               
             
             
               
                 1 
                 1 
                 1 
                 1 
               
               
                 1 
                 ½ 
                 1 
                 2 
               
               
                 1 
                 2 
                 2 
                 1 
               
               
                   
               
             
          
         
       
     
         [0031]    In the example of a paddle switch  20  being used in conjunction with a rotary milking parlor, a suitable paddle switch  20  will be made of a nominal quarter-inch thickness polyurethane, having a paddle  22 , 13.5 inches long; a first send  24 , 4.25 inches long; a second end  26 , 8.55 inches long; and a mounting portion  28 , 2.70 inches long. 
         [0032]    The first end  24  includes an end portion  90  that is 1.75 inches long and 2.25 inches high; and a neck portion  92  that is 2.5 inches long and 1.55 inches high. The second end  26  is 2.25 inches long, and has a 0.25 inch hole  98 , 2.12 inches from the distal end of the second end  26 . The mounting portion is 4.1 inches high. All corners preferably have a 0.25 inch radius with the exception of the distal end of the second end  24 , which preferably has square corners. 
         [0033]    All dimensions provided above are specified, but manufacturing tolerances and nominal material thickness tolerances may affect actual dimensions of a manufactured product. 
         [0034]    In any of these examples, the mounting plates  34  act as a “living hinge” that permits movement of the paddle  22 , but requires no mechanical hinges or separate springs, although springs could be used to enhance responsiveness. 
         [0035]    Preferably, the paddle  22  is a nominal ¼″ polyurethane and the mounting plates are 0.105″ stainless steel. Alternatively, the mounting plates  34  are of a thickness and material that enable them to be flexible when the second end  26  of the paddle  22  is moved during activation. The flexibility and resiliency of the mounting plates  34  in this alternative obviates the need for hinges or other mechanical and spring-loaded devices. 
         [0036]    Preferably when sensing animal movements, the mounting portion  28  is joined to a structure  44  so that the second end  26  is a length that is two-thirds to three-quarters of the total paddle  22  length. The length of the second end  26  will depend on the item to be contacting the second end  26  and the sensitivity of the inductive sensor  32 . For example, a gate sensor may use a first end  24  longer than the second end  26  of the paddle  22  because a gate sensor would require a longer travel of the first end  24  for proper sensing of gate movement. 
         [0037]    The mounting plates  34  are depicted as separate components attached to the mounting portion  28  of the paddle  22 , but the mounting plates  34  could be the same material as the paddle  22  or formed integrally with the mounting portion  28  of the paddle  22 . 
         [0038]    In use, the second end  26  is contacted by an object or animal and the paddle  22  pivots about the mounting portion  28 . The first end  24  also pivots and moves relative to the inductive sensor  32 . When the paddle  22  second end  26  is not being contacted, it is in a “home” position. When the paddle  22  second end  26  is being contacted, it is in an “activated” position. The paddle  22  is biased toward and returns to the “home” position due to the resiliency of the mounting portion  28  or by the use of separate springs. 
         [0039]    The first end  24  of the paddle  22  has the metallic clip  30  joined thereto, as described above. The metallic clip  30  is disposed at a position to interact with the inductive sensor  32 . In the illustrated embodiment, the inductive sensor  32  is mounted on an extension  48  of a mounting plate  34  to further simplify design and reduce costs, but other types of holders could be used to mount the sensor  32  in an appropriate position. 
         [0040]    The inductive sensor  32  can be any senor that operates by electromagnetic induction and responds to movement of an object made of a ferromagnetic material, such as the metallic clip  30  in the illustrated preferred embodiment. The sensor  32  is inductive so that it does not sense dirt and water that may get into the enclosure or otherwise affect other types of sensors. Movement of the ferromagnetic material adjacent the sensor causes a voltage to be created that is transmitted through wire  50 , other conduit, or to be used to transmit a wireless signal to an appropriate receiver (not illustrated). The sensitivity of the inductive senor  32  can be selected for an appropriate application or be adjustable for tuning in the field during installation and maintenance. In a preferred embodiment, the sensor  32  is a 30 mm inductive sensor. The sensor  32  is preferably adjustable in sensitivity range from 30 mm to 1 mm. This adjustment may be made via adjustment of the sensor itself, or it may be made by adjusting the sensor  32  in the mounting plate  48 , which could be any type of holder. In the preferred embodiment, there is adjustment in the holder  48  left and right of up to 1 cm either side of the preferred sensing location to allow for fine tuning of the sensitivity. 
         [0041]    The inductive sensor  32  can also be single action or double action. In a single action application, one inductive sensor  32  is used to sense movement of the paddle  22 . In a double action application, there is a pair of inductive sensors  32  mounted near the metallic clip (preferably, one on each side of the clip)  30  so that each inductive sensor  32  sends a signal. An example of a double action sensor  32  application is a personnel or animal sensor that senses movement in both directions. The second end  26  of the paddle  22  responds to movement in both directions and the first end  24  with metallic clip  30  will move adjacent one of the sensors  32  regardless of which way the person or animal is moving. 
         [0042]    The switch  20  can be mounted on a structure  44  that is movable or stationary. For example,  FIG. 2  illustrates the switch  20  mounted on a stationary structure  44  that can be factory-made and mounted to a floor, wall, ceiling or a piece of dairy equipment in a dairy. The structure  44  illustrated in  FIG. 2  includes a base  52 , a post  54 , and a mount  56 . A shield  58  is also provided for deflecting debris and water from the switch&#39;s electronic components. A back cover  100  ( FIG. 3 ) can be used for enclosing much of the switch  20  components to keep out most of any dirt and water in the area. Of course, the paddle  22  second end  26  extends out to be engaged by the necessary machinery or animals. The structure  44  can be made of any suitable material, such as stainless steel, aluminum, or plastic. 
         [0043]      FIG. 3  illustrates a portion of a rotary milking parlor having a floor  60 , a stationary platform  62 , a rotating platform  64 , and milking machines  66  with detacher arms  68 . The detacher arms  68  are raised and lowered depending upon whether the rotary platform  64  is in a position for milking cows or in a rest position. 
         [0044]    A stand structure  44  is mounted on the floor  60  with a switch  20  mounted thereon to determine the position of the rotating platform  64  and whether the detacher arms are in a desired position. 
         [0045]    The switch  20  in such an embodiment has a second end  26  that is sized and positioned to be contacted by detacher arm chain, milking unit, pulsation hose, or milk hose  72  that is joined to the rotating platform  64 . The switch  20  is then activated as the detacher arm chain, milking unit, pulsation hose, or milk hose  72  rotates past the stationary switch  20 . Alternatively, the switch  20  could be mounted on the rotating platform  64  and arranged to contact a stationary component. 
         [0046]      FIG. 4  illustrates a switch  20  in accordance with the present invention and disposed in a cow alley or gate  78 . The alley  78  includes a pair of spaced apart fences  80 . This switch  20  includes a first end  24 , a second end  26 , a mounting portion  28 , a metallic clip  30 , and an inductive sensor  32 . The switch  20  is mounted to the fence  80  with suitable fasteners  36 . In this embodiment, the second end  26  is sized to be contacted by a cow  82  as it passes the switch  20 , but not so large that the cow  82  is discouraged from walking through. 
         [0047]    The foregoing detailed description of the invention is intended for clearness of understanding the present invention, and no unnecessary limitations therefrom should be read into the following claims.