Abstract:
Disclosed is an adapter for communicating the turning output of a voltage regulator tap change mechanism to a tap position indicator. The adapter has a receptor that axially receives the turning output of the change mechanism and includes an intermediate gear that meshes with the input to the position indicator. This reverses the turning direction of the change mechanism output as applied to the position indicator. The adapter and position indicator have cooperating nesting members that align the adapter and position indicator to accomplished the meshing of the intermediate gear with the input to the position indicator.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates generally to means for registering the tap position of a voltage regulator and more particularly to an adapter for communicating the output of a tap change mechanism to the input of a tap position indicator.  
         BACKGROUND OF THE INVENTION  
         [0002]    The use of voltage regulators to provide constant voltage on an electrical power distribution system is known in the art. As the load on the electrical system changes, a change mechanism within the voltage regulator seeks to maintain a constant voltage by automatically stepping from one transformer tap to another. As the mechanism steps from one tap to another, the new position is registered on a position indicator mounted to the exterior of the voltage regulator. The position indicator usually is in the form of a dial face with a single indicator hand that points to the current position of the change mechanism.  
           [0003]    It is customary for the change mechanism to include a flexible shaft. As the mechanism steps from one tap to another, the flexible shaft turns in one direction or another depending upon whether the stepping is to a higher or lower tap. The turning of the flexible shaft is used to drive the indicator hand through a system of gears within the position indicator.  
           [0004]    There are two popular styles of change mechanisms. These two styles employ opposite conventions with respect to the direction that the flexible shaft turns in response to a tap change. Consequently, two types of position indicators have been developed dedicated exclusively to one or the other of these two styles of change mechanisms.  
           [0005]    Both types of position indicators employ a common convention with respect to the movement of the indicator hand so that in each, the indicator hand moves in the same direction to indicate a tap change. However, each type of position indictor employs a gear system designed to accommodate the flexible shaft convention of one or the other of the popular styles of change mechanisms. For example, in a first common type of position indicator (hereinafter “Type A”) the gear system is arranged to move the indicator hand in the same direction as the rotation of the flexible shaft. In this type, the gear system has an input gear that is connected directly to the flexible shaft and turns in the same direction as the shaft. In the second common type of position indicator (hereinafter “Type B”) the indicator hand is geared to move in a direction opposite to the rotation of the flexible shaft. Accordingly, a position indicator dedicated to one style of change mechanism is incompatible with a change mechanism having its flexible shaft rotating in an opposite convention.  
           [0006]    Heretofore, the Type A position indicator has not been used as a direct replacement for the Type B position indicator. This is because the gear system of the Type A position indicator could not accommodate a flexible shaft that turns in a direction counter to the direction of the indicator hand. While modification of the gear system of the Type A position indicator is possible, such modification is an expensive proposition. For this reason there is a reluctance to change the gear system to make the Type A position indicator compatible with a change mechanism having a flexible shaft that turns in a direction opposite to the indicator hand.  
           [0007]    Accordingly, an object of the present invention is to provide an adapter to compensate for an otherwise incompatible direction of rotation of the flexible shaft of a change mechanism used in a voltage regulator to maintain constant voltage.  
           [0008]    Another object is to provide an adapter that permits the use of a Type A position indicator with a change mechanism having a flexible shaft that turns in a direction opposite to the direction of the indicator hand.  
           [0009]    A further object of the present invention is to provide an adapter and position indicator having mating components that cooperate to interpose a rotation reversing gear assembly between the input gear of the position indicator and the flexible shaft of a change mechanism.  
           [0010]    A still further object of the present invention is to provide an adapter including a rotation reversing gear assembly having an input end in mating axial alignment with the flexible shaft of a change mechanism.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention provides an adapter for use with a Type A position indicator. In particular, the adapter permits the use of the position indicator in association with a change mechanism having a flexible shaft that turns in the opposite direction as the indicator hand. The adapter and position indicator each have cooperating mating members that establish an alignment and operational engagement of components for reversing the direction of rotation of the flexible shaft.  
           [0012]    In this respect, the position indicator has an outward extending bearing. Journaled to this bearing is a spur gear. The spur gear represents the input to the position indicator gear assembly in that the spur gear rotates in the same direction as the indicator hand. The adapter is attachable to the position indicator and includes a seat that has a snug fit with the bearing. Accordingly, the reception of the bearing into the seat establishes a defined positional relationship between the adapter and the position indicator.  
           [0013]    Journaled to the adapter is a drive including an intermediate gear that meshes with the input spur gear when the bearing is received into the seat. The drive further includes a receptor for axially receiving and nesting a pinion at the end of the rotary shaft extending from a change mechanism. The engagement of receptor and pinion causes the intermediate gear and pinion to turn in the same direction and on the same axis. While the intermediate gear and pinion turn in concert, the meshing of the intermediate and spur gears cause the spur gear to turn in an opposite direction. This direction reversal renders the rotation of the flexible shaft compatible with a Type A position indictor having an indicator hand that turns in the same direction as the input to the position indicator gear assembly.  
           [0014]    Accordingly, the present invention may be characterized in one aspect thereof by an adapter for connecting a pinion on the end of a change mechanism flexible shaft to the input gear of a position indicator for turning the input gear in a direction opposite to the direction of rotation of the pinion, the adapter comprising:  
           [0015]    a) a plate attachable to the position indicator;  
           [0016]    b) a receptor journaled to the plate for rotation about an axis extending generally normal to the plane of the plate, the receptor having a first end for axially receiving and nesting the pinion such that the pinion and receptor turn on a common axis and the receptor is driven by the pinion;  
           [0017]    c) the plate having a first seat opening outward through one side of the plate for receiving a bearing extending from the position indicator wherein the reception of the bearing into the seat establishes a defined positional relationship between the position indicator and the plate that places the axis of the receptor parallel to and laterally spaced from the rotational axis of the position indicator input gear; and  
           [0018]    d) an intermediate gear fixed to the receptor and adapted to mesh with the input gear of the position indicator when the bearing is seated in the seat whereby the turning of the receptor by the pinion causes the input gear to turn in a direction opposite to the pinion. 
       
    
    
     DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a schematic view showing a voltage regulator and position indicator including an adapter according to the present invention;  
         [0020]    [0020]FIG. 2 is an exploded perspective view partly broken away and in section showing an adapter and the rear side of a position indicator;  
         [0021]    [0021]FIG. 3 is a sectional view of the adapter shown in FIG. 2;  
         [0022]    [0022]FIGS. 4 and 5 are views of portions of FIGS. 2 and 3 respectively on an enlarged scale;  
         [0023]    [0023]FIG. 6 is a view partly broken away and in section of an adapter according to the present invention attached to a tap position indicator; and  
         [0024]    [0024]FIG. 7 is a cross sectional view taken along lines  7 - 7  of FIG. 6. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0025]    Referring to the drawings, FIG. 1 shows the exterior housing  12  of a voltage regulator. Within the housing are the transformer windings and a change mechanism that connects to one tap or another for maintaining constant voltage. The transformer and change mechanism are conventional and form no part of the present invention. Extending from the housing  12  is a duct  14 . Various electrical cables and the flexible shaft of the change mechanism extend through this duct. A position indicator  16  at the outward end of the duct is mounted to the duct by means of an adapter generally indicated at  18 . The adapter is arranged to angle a face  20  of the position indicator downwardly to facilitate viewing by an operator standing below the voltage regulator. The position indicator is conventional (except as noted below) and its face  20  includes a dial and an indicator hand (not shown) that points to the current transformer tap position.  
         [0026]    Referring now to FIG. 2, the adapter  18  and its relationship to the position indicator  16  is shown in greater detail. For purposes of illustration, the position indicator is shown with its dial face  20  down and obscured to more clearly show the rear side  21  of the position indicator and its connection to the adapter  18 .  
         [0027]    Extending from the rear side of the position indicator is a shaft  22  (FIG. 4). The shaft  22  in turn is connected to a gear train (not shown) within the position indicator that is arranged to turn the indicator hand in the same direction as the shaft. The shaft  22  may be considered the input of the position indicator. The type of position indicator shown is intended for use with a change mechanism having a flexible shaft that turns in the same direction as shaft  22 . Accordingly, the flexible shaft of the change mechanism can be coupled directly to the shaft  22  so the flexible shaft and shaft  22  turn in concert. However, such a direct connection is not acceptable in cases where the flexible shaft turns in an opposite direction. Accordingly, the adapter of the present invention allows for the use of a Type A position indicator with such a change mechanism (i.e. one having a flexible shaft  28  that terminates in a pinion  26 , which turns in an opposite direction).  
         [0028]    Referring now to FIGS. 2 and 3, the adapter  18  is shown to include a hollow housing  30  that is generally rectangular in cross section. A first end  32  of the housing is open and is disposed at an angle with respect to the longitudinal axis of the housing. A flange  36  at the open end provides the means for attaching the adapter to the duct  14  (FIG. 1).  
         [0029]    Formed integral a second end  38  of housing is a mounting plate  40  that is disposed generally normal to the longitudinal axis of the housing. The mounting plate  40  includes the means for attaching the adapter to the rear side  21  of the position indicator  16 .  
         [0030]    The housing  30  includes an internal wall  42  (FIG. 3) that longitudinally partitions the interior of the housing. In this respect, the internal wall  42  defines a passage  44  extending through both the housing and the mounting plate to accommodate any wires or other electrical connections (not shown) that may pass between the interior of the position indicator  16  and the interior of the transformer housing  12 . The internal wall also defines an open ended chamber  46  within the hollow housing  30 . The open end of the chamber opens through the open end  32  of the housing. The opposite end of the chamber is closed and is defined by the mounting plate  40 .  
         [0031]    Formed in the mounting plate  40  by precision machining are first and second seats  48 , 50  respectively. As best seen in FIGS. 5 and 6, the first seat  48  opens outward from the mounting plate whereas the second seat  50  opens into the chamber  46 . The positioning of the two seats is such that there is a slight overlap so that an opening  52  is formed between the two seats.  
         [0032]    Disposed in the second seat  50  is a shaft  54 . The shaft is journaled in the second seat and is held in the seat by a bearing  56 . A spur gear  58 , referred to hereafter as an intermediate gear, is press fit to the shaft adjacent one end so that the outer periphery of the intermediate gear rotates through the opening  52  and into the first seat  48 . The opposite end  60  of the shaft is larger in diameter than the first end. The larger shaft end  60  extends through the bearing  56  and into the chamber  46 . The end  60  of the shaft is bored and slotted to form a plurality circumferentially spaced longitudinally extending keys  62 . These keys define a receptor adapted to mesh and engage about the periphery of the pinion  26  as shown in FIG. 7.  
         [0033]    The first seat  48  of the mounting adapter is sized to receive the input spur gear  24  of the position indicator. Moreover, as best seen in FIG. 4, the shaft  22  mounting the input spur gear  24  extends through a bearing  64  wherein the outside diameter of bearing  64  is machined to fit snugly into the first seat  48  for purposes set out hereinbelow.  
         [0034]    [0034]FIG. 6 shows the adapter  18  attached to the position indicator  16 . In this respect, the mounting plate  40  is placed flush on the rear side  21  of the position indicator with the bearing  64  received into the seat  48 . The reception of bearing  64  into the seat  48  establishes a defined relationship between the position indicator  16  and the mounting plate  40  that places the axis  66  of the shaft  54  parallel to and laterally off set from the axis  68  of the input gear  24 . This arrangement allows input spur gear  24  to mesh with the periphery of the intermediate gear  58  that turns through the opening  52  and into the seat  48 .  
         [0035]    The flexible shaft  28  of the change mechanism then is led through the housing open end  32  and into the chamber  46 . The pinion  26  on the end of this shaft is axially received into the receptor defined by the keys  62 . Any suitable means, such as a setscrew (not shown) in the side of the housing may be used to prevent the pinion from pulling out from between the keys  62 .  
         [0036]    As best seen in FIG. 7, the pinion  26  is nested between the keys  62  and is held by the keys so that the pinion  26  is axially aligned with the shaft  54  and is coupled directly to the shaft. As the pinion  26  turns, this movement is transmitted to the shaft  54  and to the intermediate gear  58  fixed to this shaft. The gear  58 , in turn, is meshed with the input spur gear  24  so by interposing the intermediate gear  58  between the pinion  26  and input spur gear  24 , the input spur gear  24  and shaft  22  turn in a direction opposite to the pinion  26 .  
         [0037]    Thus, the adapter of the present invention allows a Type A position indicator (indicator hand turns in the same direction as the flexible shat) to replace a Type B position indicator by attaching to a flexible shaft having a contrary rotation convention. Moreover, the adapter  16  provides in one integral structure, an intermediate gear to reverse the direction of rotation, means to axially couple the pinion of the flexible shaft to the intermediate gear and the means to properly align the intermediate gear with the input spur gear of the position indicator. Also, part of the integral structure is a passage  44  to accommodate wires that may pass between the change mechanism and the position indicator.  
         [0038]    Thus, it should be appreciated that the present invention accomplishes its intended objects in providing an adapter for mating a voltage regulator change mechanism to a position indicator. The adapter effectively reverses the turning direction of the pinion at the end of the change mechanism flexible shaft so the Type A position indicator can be used with a flexible shaft that turns in a contrary direction.  
         [0039]    The adapter has input and output ends that mate respectively with the pinion of the change mechanism and the input spur gear of the position indicator. A gear intermediate these ends effects the change of the direction of rotation needed to mate the output of the change mechanism to the position indicator. Moreover, the input end of the adapter includes a receptor that axially aligns with the pinion of the change mechanism to facilitate the connection of one to the other.