Abstract:
In a vehicle battery relay assembly for disconnecting or isolating a vehicle battery from a connection line, a housing is provided having a solenoid and a switch activated by the solenoid. The switch electrically connects and disconnects a first contact terminal for connection to the vehicle battery and a second contact terminal for connection to the connection line. The solenoid has a solenoid coil. A rotatable ratchet gear rotates by engagement with a pawl, the pawl being connected to a plunger of the solenoid. The switch comprises a contact element coupled to the ratchet gear, the contact element having at least first and second projecting contact points. The contact element is positioned relative to a contact surface of the first and second contact terminals such that given a first rotation of the contact element the first and second contact terminals are electrically connected and given a subsequent second rotation the first and second contact terminals are electrically disconnected.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application titled “IMPROVED VEHICLE BATTERY RELAY ASSEMBLY” U.S. Ser. No. 62/085,745, filed Dec. 1, 2014, which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    In vehicles powered by a vehicle battery it is frequently necessary to provide a high current battery relay for disconnecting the vehicle battery from a vehicle load powered by the vehicle battery. It is also useful to isolate a vehicle battery from another vehicle battery. 
         [0003]    In view of high switching currents it has been a problem in the prior art to provide a reliable battery relay for switching such high vehicle battery currents while at the same time providing reduced wear and increased life cycle of the battery relay. 
         [0004]    With such prior art battery relays it has been known to employ rotary contact type relays which are driven by motors which are slow to operate and can cause arcing. It is also known to provide solenoid operated relays where the contacts move linearly to make and break contact (for example a starter relay). 
         [0005]    Traditional prior art ratchet and pawl assemblies are normally flat and have pointed teeth or gears for motion, which increases friction, wear, and force on a small surface. 
       SUMMARY 
       [0006]    It is an object to decrease the size of a typical battery relay for switching high currents, reduce the force required to accomplish the switching function without increased arcing and thereby reduce the cost, increase the reliability and the life cycle, and to reduce wear for switching high currents from a vehicle battery when the battery is disconnected from the vehicle load or when the vehicle battery is isolated from another vehicle battery. 
         [0007]    In a vehicle battery relay assembly for disconnecting or isolating a vehicle battery from a connection line, a housing is provided having a solenoid and a switch activated by the solenoid. The switch electrically connects and disconnects a first contact terminal for connection to the vehicle battery and a second contact terminal for connection to the connection line. The solenoid has a solenoid coil. A rotatable ratchet gear rotates by engagement with a pawl, the pawl being connected to a plunger of the solenoid. The switch comprises a contact element coupled to the ratchet gear, the contact element having at least first and second projecting contact points. The contact element is positioned relative to a contact surface of the first and second contact terminals such that given a first rotation of the contact element the first and second contact terminals are electrically connected and given a subsequent second rotation the first and second contact terminals are electrically disconnected. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic diagram illustrating the improved vehicle battery relay assembly employed for switching high currents from a vehicle battery to a vehicle load during battery disconnect or isolation from another vehicle battery; 
           [0009]      FIG. 2  is a perspective view from beneath a housing of the improved vehicle battery relay assembly; 
           [0010]      FIG. 3  is an exploded perspective view showing various components employed in the improved vehicle battery relay assembly; 
           [0011]      FIG. 4A  is a top view of the improved vehicle battery relay assembly with a housing base removed and the solenoid coil shown in an inactive state with the plunger released; 
           [0012]      FIG. 4B  is a top view of the improved vehicle battery relay assembly with a housing base removed and the solenoid coil shown in an active state with the plunger drown into the solenoid coil; 
           [0013]      FIG. 4C  is a section view along section line  4 C- 4 C in  FIG. 4A  and showing the ratchet gear mounting in greater detail; 
           [0014]      FIG. 5  is a perspective view of terminal and switch components of the assembly of  FIG. 1 ; 
           [0015]      FIG. 6  is a top partial perspective view of terminal and switch components of the assembly of  FIG. 1  including a contact washer; and 
           [0016]      FIG. 7  is a top partial perspective view of the terminal and switch components in  FIG. 6  but with the contact washer removed for viewing clarity. 
       
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0017]    For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the preferred exemplary embodiments/best mode illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and such alterations and further modifications in the illustrated embodiments and such further applications of the principles of the invention as illustrated as would normally occur to one skilled in the art to which the invention relates are included herein. 
         [0018]    As shown in  FIG. 1 , a vehicle battery  1  is to be disconnected from a connection lead  3  connected to a vehicle load or to another vehicle battery. An improved vehicle battery relay assembly  10  comprises a switch formed of a contact washer  14  activated by solenoid  15 . The switch formed as the contact washer  14  is connected at one side to a contact bolt  16  having respective screw  34 E connected to the vehicle battery  1  and at the opposite side to a contact bolt  17  having respective screw  34 D connected to the lead  3 . 
         [0019]    A PC board  18  having a solenoid control circuit thereon is provided. Battery power for the control circuit is provided by contact bolt  16  with respective screw  34 E. The solenoid coil  15 A of the solenoid  15  has lead wires  15 AA and  15 AB which are directly soldered at their respective ends to PC board  18  at termination holes  8  and  9  also shown in  FIG. 4A . The control circuit PC board  18  has an input control signal line 1 shown by reference numeral  22  connecting at terminal screw  19  having respective screw  34 C and input control signal line 2 shown by reference numeral  23  connecting at terminal screw  20  having respective screw  34 B. A −V line  24  connects to terminal screw  21  having respective screw  34 A. It is understood that −V may be the vehicle ground, but not necessarily. 
         [0020]    The PC board control circuit may have various configurations, depending on desired function and/or use. For example when the relay assembly is to function as a remote manual battery disconnect relay, the circuit on the PC board  18  is configured to allow remote disconnect of the vehicle battery from the vehicle electrical system functioning as the load. For the battery disconnect, with low voltage sensing the vehicle battery  1  can be automatically disconnected from the vehicle electrical system when the ignition is off, to prevent the battery from being drained (for example headlights accidently having been left on). As a third configuration the relay assembly can operate as either a manual battery disconnect or low voltage sensing automatic disconnect depending on user selections input on the control signal lines 1 and 2 shown at  22  and  23 . As a battery isolation relay between two separate vehicle battery systems, the assembly  10  connects the two separate battery systems together when either battery is being charged, and can isolate the two electrical systems to prevent draining battery  1  by the second system. 
         [0021]    As shown in  FIG. 2 ,  FIG. 3 , and  FIG. 4A , the assembly includes a housing  11  having housing base  12  and mounting ears  11 A,  11 B, and  11 C for mounting the housing to a mounting surface not shown. On a terminal surface  11 D (see  FIG. 2 ) the contact bolts  16  and  17 , and the terminal screws  19 ,  20 , and  21  are incorporated, such as by insert molding into the housing. 
         [0022]    As shown in the perspective exploded view of  FIG. 3 , the assembly  10  has the housing  11  and the base  12  connected thereto by phillips head screws  13 A,  13 B,  13 C,  13 D and  13 E received in mounting holes  7 A,  7 B,  7 C,  7 D and  7 E. The housing base  12  has aperture mounting projections  12 A,  12 B,  12 C,  12 D and  12 E for receiving the mounting screws  13 A,  13 B,  13 C,  13 D, and  13 E therethrough. 
         [0023]    As shown in  FIG. 4C  a circular pin  38  protruding from an inner surface of base  12  is received in a circular pocket  28 B of ratchet gear  28  to thus provide a top circular pivot point for the ratchet gear  28 . Pin  38  has a conical shaped end  38 A which matches a conical shaped end of pocket  28 B. These cooperating conical shaped surfaces ensure the ratchet gear  28  remains on center as it rotates about pin  38 . The ratchet gear  28  has extending downwardly therefrom a square shank  28 E which is integral to the ratchet gear  28  and has a circular pivot hole  28 F up inside the square shank  28 E (see  FIG. 4C ) which sits on a circular pin  4  in housing  11  described hereafter with respect to  FIG. 7  as another pivot point allowing circular rotation of the ratchet gear  28 . 
         [0024]    As shown in  FIG. 3 , beneath the housing base  12  is illustrated a pawl  27  rotatable about retention pin  25  received through a pivot aperture  26  of pawl  27 . Pawl  27  has a pawl head  27 A, spring member  27 B with an end face  27 D, and pawl stop  27 C. The pawl head  27 A engages in grooves  28 A between teeth  5  of the ratchet gear  28 . Teeth  5  are adjacent a disc  28 C. Disc  28 C of the ratchet gear  28  has an annular pocket  28 D (see  FIG. 4C ) receiving therein a compression spring  29  followed by the contact washer  14  functioning as the previously described switch contact element. 
         [0025]    Solenoid  15  comprises a solenoid coil  15 A with the solenoid leads  15 AA and  15 AB. The solenoid further comprises a return spring  31 , plunger  32 , and retention ring  33 . A foam pad  2  is provided adjacent solenoid  15  for cushioning the solenoid  15 . 
         [0026]    The previously described screws  34 A- 34 E are torx-drive pan head retention screws and mount the PC board  18  in the housing and establish electrical contact to the control circuit on the PC board. 
         [0027]    Beneath the PC board  18  are provided the contact bolts  16  and  17  and the terminal screws  19 ,  20 , and  21 . 
         [0028]    A sealing member  34  is provided for sealing between the housing base  12  and the housing  11 . 
         [0029]    In the top view of  FIG. 4A  with the housing base  12  removed one can see in plain view the arrangement of the various components described previously. 
         [0030]    Referring to the perspective view of  FIG. 5 , the terminal screws  19 ,  20 , and  21  and contact bolts  16  and  17  together with switch element contact washer  14  are illustrated. One may observe how the circular contact washer  14  functions for establishing an electrical connect and disconnect between a top end contact surface  16 A and  17 A of the contact bolts  16  and  17  by use of protruding contact points  14 A, B, C, and D formed as downwardly protruding bumps from a main body  14 E of the washer (see also  FIG. 6 ). The ratchet gear  28  is integral with the square shank  28 E. This square shank  28 E protrudes downwardly through a square aperture  14 F in the main body  14 E of the contact washer  14  and has the circular pivot hole  28 F at a bottom thereof (see  FIG. 4C ). 
         [0031]    In  FIG. 6  one may observe in the partial perspective view how the contact washer  14  with its contact points  14 A-D as bumps is positioned relative to the top end contact surface  16 A or  17 A of the contact bolts  16  and  17 . 
         [0032]    In  FIG. 7  the contact washer  14  has been removed and one may observe a housing plastic ring  36  having V-grooves at  36 A, B and circular cut-outs  36 C and  36 D conforming to a periphery of a respective head forming the top end contact surface  16 A or  17 A of the contact bolts  16  and  17 . 
         [0033]    Further details and explanations will now be provided concerning various components of the assembly. The contact bolts  16 ,  17  are copper and the terminal screws  19 ,  20 , and  21  are steel, all custom cold-headed with holes in a center of the head of the bolts and of the screws, respectively. They are insert molded into the housing in such a way that the heads of all the bolts and screws will be on a same plane. The printed circuit board  18  rests on a common plane of the heads of the terminal bolts  16 ,  17  and the terminal screws  19 ,  20 , and  21 . The printed circuit board mounting screws  34 A-E self-thread into holes in heads of the contact bolts  16 ,  17  and terminal screws  19 ,  20 , and  21  and provide an electrical connection from the printed circuit board to outside of the housing and mechanically secure the printed circuit board inside the housing. 
         [0034]    When voltage is applied to the solenoid coil  15 A, magnetic force pulls the plunger  32  (shown in  FIG. 4A  not yet pulled in) inside and down as shown in  FIG. 4B . The downward motion is indicated by arrow  6  in  FIG. 4B . As shown in  FIGS. 4A and 4B , the plunger  32  pulls the pawl  27  since it is linked thereto by the retention pin  25 . The pawl in turn grabs a tooth  5  as illustrated in  FIG. 4A  of the ratchet gear  28  converting linear motion into rotary motion and spinning the ratchet gear by 45° as shown in  FIG. 4B . The housing base  12  as shown in  FIG. 3  provides one pivot point as the pivot pin  38  is received in the circular pocket  28 B of the ratchet gear  28 . The ratchet gear  28  also has the circular pivot hole  28 F on the other side as shown in  FIG. 4C  which receives the housing circular pin  4 . As the plunger  32  reaches its end of travel and bottoms inside the solenoid  15 , pawl stop  27 C (see  FIG. 4B ) touches an inside surface of the side of housing  11 , preventing pawl  27  from moving sideways, and insuring that the pawl head  27 A stays engaged with the ratchet teeth  5 , thus preventing the ratchet gear  28  from over spinning. This stop mechanism assures that the contacts  14 A- 14 D on washer  14  stop consistently at the appropriate position. When power to the solenoid coil  15 A is removed the plunger  32  and pawl  27  are moved away from the solenoid coil  15 A by the return spring  31  until the plunger end surface  32 A impacts a stop rib  43  located on a bottom side of the housing base  12  shown in dashed lines in  FIG. 3 , thus positioning plunger  32  and the pawl  27  into a rest position allowing it to grab a next tooth  5  on the ratchet gear  28  on a next actuation of the solenoid coil  15 . 
         [0035]    The pawl  27  has an integral spring member  27 B with the end face  27 D (see  FIGS. 3 and 4A ) which keeps the pawl spring loaded against the teeth  5  of the ratchet gear  28 . One side of the spring member  27 B is integral to the pawl  27  and provides the initial bending spring force. On the other side of the spring member there exists the end face  27 D which initially moves freely with the spring member  27 B, and then makes contact and slides along the main body of the pawl  27 . This contact provides an increased spring force, providing a two-step spring force through the rotational travel of the pawl  27  about the pin  25 . 
         [0036]    As shown in  FIG. 3 , during an assembly process the housing base  12  is screwed down to the housing  11 . The housing base  12  pushes on the ratchet gear  28 , compressing the compression spring  29 , which in turn provides constant contact pressure to the contact washer  14 . The contact washer  14  rotates and can move vertically on square shank  28 E of ratchet gear  28  to compensate for surface wear and also to permit constant pressure by virtue of the compression spring  29  to contact bolts  16  and  17 . During a single rotation, the contact washer does not move vertically. It only slides from contact bolts  16  and  17  to contact ring  36 , thus maintaining contact compression height of compression spring  29  and constant spring force throughout 360° of rotation. 
         [0037]    As shown in  FIG. 5 , the ratchet gear  28  has the square shank  28 E which fits into the square aperture  14 F in the contact washer  14 . As the pawl  27  rotates the ratchet gear  28 , the ratchet gear integral with the square shank  28 E also rotates the contact washer  14 . 
         [0038]    The contact washer  14  as previously described has the four contact points  14 A, B, C, D shaped as projecting bumps. These points are located at 90° positions. Each time the solenoid  15  is operated with a voltage, the contact washer  14  spins 45°. As shown in  FIG. 6 , in one rotational position two opposing contact points  14 B and  14 D for example make a connection between the top end contact surfaces  16 A,  17 A of two contact bolts  16 ,  17 . In the next rotation position none of the four contact points are touching the contact bolt top end contact surfaces and the circuit is open. The housing plastic ring  36  as illustrated in  FIG. 7  is provided on which the contact points  14 A-D ride when not touching the contact bolts  16 ,  17 . This ensures that the contact washer  14  does not move up and down the square shank  28 E of ratchet gear  28 . In this way the amount the compression spring  29  is compressed does not change and the force remains constant. The solenoid force only needs to rotate the contact washer  14  and does not need to work the compression spring  29 , thereby reducing a total force required, and the associated size of the solenoid required to produce the force. Using a solenoid is important in that the motion is quick, and thus the open and closing of the contact is quick, thus reducing arcing associated with slow switching speeds. 
         [0039]    As illustrated in  FIGS. 6 and 7 , the housing plastic ring  36  design ensures that the contact points  14 A, B, C, D of the contact washer  14  slide on and off the contact bolts  16  and  17 , and the V-shape grooves  36 A, B in the plastic ring  36  ensure when one opposing pair of contact points are sitting on the top end contact surfaces  16 A,  17 A of the contact bolts  16 ,  17  such as contact points  14 B,  14 D in  FIG. 6  the other opposing pair of contact points  14 A,  14 C are hanging in free air, thus ensuring all spring  29  force is transferred to a contact force between the contact points  14 B,  14 D and the top end contact surfaces  16 A,  17 A of the contact bolts  16  and  17 . 
         [0040]    From a mechanical stand point, the rotary motion contact washer  14  is powered by the linear motion solenoid  15 . The plastic pawl  27  incorporates the spring member  27 B to push the pawl head  27 A against the ratchet teeth  5 . 
         [0041]    The ratchet gear  28  and the pawl  27  are not orientation/gravity dependent due to the live spring member  27 B for operation. This is all accomplished by having all the components needed for that incorporated into one—the pawl  27 . 
         [0042]    By using a linear solenoid with a pawl and ratchet mechanism to convert linear motion to rotary motion, the contact can be moved quickly resulting in nearly an instantaneous contact versus the slower rotary motor/gear mechanism. As a result the opportunity for arcing is greatly reduced. Also utilizing a rotary contact configuration allows for a constant spring contact force versus the linear motion contact which has to develop the contact force each time the solenoid is energized. 
         [0043]    The ratchet gear  28  and pawl  27  design has an organic shape to it. Traditional ratchets and pawls are normally flat and have pointed teeth or gears for motion increasing the friction, wear, and force on a small surface. The present design has a large bearing surface that more imitates a bearing and distributes the force over the entire face, thus reducing wear and increasing life cycle. 
         [0044]    From an electrical standpoint the assembly of the preferred embodiment has the following advantages. The printed circuit board  18  is incorporated inside the housing  11  together with the solenoid  15  and contacts. Furthermore, the printed circuit board  18  is attached to screws which are insert molded in plastic to permit connection to external control. The screws are fabricated with a hole in the center of the respective heads so that the printed circuit board will lay flat against all the heads and make electrical connection. 
         [0045]    The control circuit on the printed circuit board prevents the solenoid coil  15 A from overheating or failing by providing overcurrent protection of the solenoid coil. Also there is a time to limit operation of the solenoid coil. By providing these electronics on the printed circuit board these features are done internally of the assembly. 
         [0046]    Since the printed circuit board  18  is placed inside the housing  11  of the assembly, the assembly can perform different functions. For example, as previously described, the assembly can be a battery disconnect to allow remote manual disconnect of the vehicle battery from the vehicle electrical system as the load. Also there may be a battery disconnect with low voltage sensing such that the vehicle battery can be automatically disconnected from the vehicle electrical system when ignition is off and the battery is being drained (i.e. headlight accidently left on). In another alternative as a battery isolation relay between two separate vehicle battery systems, the assembly can connect the two together when either battery is being charged, and can isolate the electrical systems to prevent draining one battery from the second system. In this last alternative the controls on printed circuit board  18  sense battery voltages to automatically provide this function. 
         [0047]    Although preferred exemplary embodiments are shown and described in detail in the drawings and in the preceding specification, they should be viewed as purely exemplary and not as limiting the invention. It is noted that only preferred exemplary embodiments are shown and described, and all variations and modifications that presently or in the future lie within the protective scope of the invention should be protected.