Abstract:
A rearview mirror for a motor vehicle comprises an internal frame supporting a reflective element and a motorized tilt actuator assembly for adjusting the reflective element about perpendicular axes. The reflective element is attached to the internal frame through a pivot connection. A positional memory module comprising a separate assembly is supported by the internal frame adjacent the pivot connection for electrically determining the horizontal and vertical tilt of the reflective element at a selected position as a change in voltage through a pair of simple electrical circuits. The reflective element can be returned to the selected position by adjusting the horizontal and vertical tilt of the reflective element according to the changes in voltage.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. provisional application Ser. No. 60/319,977, filed Feb. 27, 2003, which is incorporated herein in its entirety. 

   FIELD OF THE INVENTION 
   The invention relates to mirrors for automotive vehicles. In one aspect, the invention relates to a tilt-adjustable rearview mirror comprising a modular positional memory apparatus for returning a mirror to a preselected tilt orientation. 
   DESCRIPTION OF THE RELATED ART 
   Rearview mirrors are standard equipment on automotive vehicles, and can vary considerably in size depending upon the size of the vehicle to which the mirror is attached. Rearview mirrors frequently comprise a motorized tilt actuator controlled from within the vehicle for adjusting the horizontal and vertical tilt of the mirror about a fixed pivot point. The tilt actuator can also incorporate a positional memory device which “remembers” one or more preselected tilt orientations and which can control the readjustment of the mirror to return the mirror to a preselected, memorized tilt orientation. The positional memory device comprises a pair of movable plungers whose movement corresponds to a change in a voltage through a simple electrical circuit. The plungers are attached to the mirror and move with the horizontal and vertical tilting of the mirror and return a signal representative of the horizontal and vertical position of the mirror to an onboard controller. 
   A large selection of tilt actuators having positional memory devices must be available to accommodate a range of mirror sizes for proper positioning of the tilt actuator away from the pivot point and the positional memory device adjacent the pivot point which increases manufacturing time and cost. Further, the failure of either the positional memory device or the tilt actuator frequently necessitates replacement of the entire assembly, leading to premature replacement of the operating part and increasing the cost of these devices. 
   SUMMARY OF THE INVENTION 
   In one aspect, the invention relates to a vehicular rearview mirror assembly, comprising: a frame; a reflective element attached at the frame for providing an occupant of the vehicle with a rearward view; a tilt actuator attached at the frame and the reflective element for selectively tilting the reflective element relative to the frame; and a positional memory element located away from the tilt actuator and interposed between the frame and the reflective element, wherein a position of the reflective element is correlated to an output signal from the positional memory element so that movement of the reflective element from a first position to a second position results in a change in said output signal. 
   Various embodiments of the invention are also contemplated. For example, the positional memory module can be selectively attached and removed from between the frame and the reflective element without requiring disassembly of the tilt actuator. The positional memory module can be mounted to the frame in a chamber separate from the attachment of the tilt actuator to the frame. 
   The positional memory module can be located adjacent to a pivot point located between the reflective element and the frame. The reflective element can be returned to the first selected position by actuating the tilt actuator until the positional memory module generates an electrical output signal which is identical to the first electrical output signal. 
   The positional memory module can be electrically energized. The first output signal can be electrical. The second output signal can be electrical. The frame can be a housing for the mirror. A wiper can be associated with one of the positional memory element and the frame and a contact can be associated with the other of the positional memory element and the frame, and wherein the wiper abuts the contact during movement of the positional memory element with respect to the frame. Movement of the positional memory element with respect to the frame can cause movement of the wiper with respect to the contact. 
   A sensor can be provided, wherein movement of the positional memory element with respect to the frame alters the output signal, wherein said output signal is received by the sensor. The sensor can detect the output signal via the Hall effect. The sensor can detect the output signal via a magnetic resonance effect. The sensor can detect the output signal without contact with the positional memory element. The sensor can detect the output signal by contact with the positional memory element. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  is a perspective view of a portion of an automotive vehicle having a mirror assembly according to the invention. 
       FIG. 2  is an exploded view of an embodiment of the mirror assembly shown in  FIG. 1 , the mirror assembly comprising an internal frame supporting a tilt actuator assembly for horizontally and vertically tilting a reflective element about a fixed pivot point and housing a positional memory module according to the invention. 
       FIG. 3  is a close-up perspective view of a first side of the internal frame shown in  FIG. 2  showing the positional memory module supported in the internal frame. 
       FIG. 4  is a close-up perspective view of a second side of the internal frame shown in  FIG. 3  showing a pair of movable plunger assemblies comprising a portion of the positional memory module extending from the internal frame adjacent the fixed pivot point. 
       FIG. 5  is a close-up perspective view of the positional memory module supported in the internal frame shown in  FIG. 3 . 
       FIG. 6  is a first exploded view of the positional memory module shown in  FIG. 2 . 
       FIG. 7  is a second exploded view of the positional memory module shown in  FIG. 2 . 
       FIG. 8  is a perspective view of a memory module base comprising a portion of the positional memory module shown in  FIG. 2 . 
       FIG. 9  is a close-up perspective view of a plunger assembly shown in  FIG. 4  comprising a plunger and a sweeper. 
       FIG. 10  is a close-up perspective view of the plunger shown in  FIG. 9 . 
       FIG. 11  is a close-up perspective view of the sweeper shown in  FIG. 9 . 
       FIG. 12  is a close-up perspective view of a circuit board comprising a portion of the positional memory module shown in  FIG. 6 . 
       FIG. 13  is a close-up perspective view of an alternative embodiment of the circuit board shown in  FIG. 12 . 
       FIG. 14  is a schematic view showing an exemplary circuit diagram applicable to both embodiments of the circuit board shown in  FIGS. 12–13 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to the figures and in particular to  FIGS. 1 and 2 , a mirror assembly  10  according to the invention is shown attached to a motor vehicle  12  in a conventional fashion. The mirror assembly  10  comprises a housing  14  enclosing a reflective element  16  attached to a glass case  20  which is tiltably mounted to a tilt actuator assembly  22  supported within a tilt actuator assembly chamber  30  comprising a portion of an internal mounting frame  18 . The internal mounting frame  18  comprises a support end  26  which is attached to the vehicle  12 , a cantilever end  28  which extends away from the vehicle  12 , and a glass case side  48  intermediate the support end  26  and the cantilever end  28  and facing a reflector side  24  of the glass case  20 . In the embodiment shown in the figures, the tilt actuator assembly  22  is located proximate the support end  26 . 
   The tilt actuator assembly  22  comprises an upper jackscrew  32  and a lower jackscrew  34  which extend through jackscrew apertures  49  in the glass case side  48  and are pivotably attached to the frame side  24  of the glass case  20  for tilting the glass case  20  and the reflective element  16  when the jackscrews  32 ,  34  are selectively extended and retracted. The tilt actuator assembly  22  can comprise a single motor or a dual motor tilt actuator assembly. An example of a suitable tilt actuator assembly is described in U.S. patent application Ser. No. 60/319,753, filed Dec. 4, 2002, entitled “Bottom-Load Actuator for Vehicular Rearview Mirror,” which is incorporated herein by reference. 
   As shown also in  FIGS. 3 and 5 , a positional memory module  40  according to the invention is also supported within a generally rectilinear memory module chamber  42  comprising a portion of the internal mounting frame  18  at the cantilever end  28 . Extending outwardly of the internal mounting frame  18  adjacent the memory module chamber  42  is a flexible finger  44  having a hook  46  at a free end thereof for engaging the positional memory module  40  in an interference fit as hereinafter described. The internal frame  18  is also provided with a pivot pedestal  38  which is pivotably attached to the frame side  24  of the glass case  20  and comprises a fixed point about which the glass case  20  and the reflective element  16  can pivot. 
   As shown in  FIG. 4 , the tilt actuator assembly  22  is enclosed within the internal mounting frame  18  so that the jackscrews  32 ,  34  define a jackscrew axis  36  which is oriented generally vertically when the mirror assembly  10  is attached to the motor vehicle  12 . The pivot pedestal  38  is attached to the internal mounting frame  18  so that the pivot pedestal  38  and the upper jackscrew  32  define a horizontal pivot axis  39  which is orthogonal to the jackscrew axis  36 . 
   Referring now to  FIGS. 6–8 , the positional memory module  40  comprises a generally rectilinear memory module base  50 , adapted for slidable insertion into the memory module chamber  42 , and a generally rectilinear removable memory module cover  142 , the memory module base  50  and the memory module cover  142  defining a chamber  143  enclosing a first plunger  100 , a second plunger  102 , and a circuit board  160 . The memory module base  50  comprises a front wall  52 , a first sidewall  54  and a second sidewall  56  in parallel, spaced-apart juxtaposition extending orthogonally away from the front wall  52 , and a rear wall  58  extending from the first sidewall  54  to the second sidewall  56  in parallel, spaced-apart juxtaposition to the front wall  52 . The walls  52 – 58  transition to a bottom wall  60  extending orthogonally thereto. In the preferred embodiment, the front wall  52  is provided with a front cover slot  62  extending therethrough, and a plurality of wiring pass-throughs  98 . 
   In the preferred embodiment, the side walls  54 ,  56  are provided with side cover slots  64 ,  66 , respectively, extending therethrough, and the rear wall  58  is provided with a rear cover slot  68  extending therethrough. The walls  52 – 60  define a first plunger chamber  70  and a second plunger chamber  72  in spaced-apart juxtaposition. The first plunger chamber  70  comprises a first plunger cradle  74  having a first cylindrical portion  78  and a first cradle extension  82  to define a first plunger seat  86 . The second plunger chamber  72  comprises a second plunger cradle  76  having a second cylindrical portion  80  and a second cradle extension  84  to define a second plunger seat  88 . 
   Referring specifically  FIG. 8 , a first rib  90  is an elongated protuberance extending from the first sidewall  54  into the first plunger chamber  70  in spaced-apart juxtaposition to the rear wall  58  to define a first slot  94 . A second rib  92  is an elongated protuberance extending from the second sidewall  56  into the second plunger chamber  72  in spaced-apart juxtaposition to the rear wall  58  to define a second slot  96 . 
     FIGS. 6 and 7  show a first plunger  100  in cooperative association with the first plunger chamber  70  and a second plunger  102  in cooperative association with the second plunger chamber  72 .  FIGS. 9–11  show the plungers  100 ,  102  in detail, the plungers  100 ,  102  being identical. The first plunger  100  is an elongated, generally cylindrical member comprising a cylindrical first shaft  104  transitioning at a first end to a first ball  106  and at a second end to a first plunger bead  124  comprising a somewhat enlarged collar-like portion encircling the shaft  104  and having a diameter somewhat greater than the diameter of the shaft  104 . Similarly, the second plunger  102  is an elongated, generally cylindrical member comprising a cylindrical second shaft  106  transitioning at a first end to a second ball  108  and at a second end to a second plunger bead  126  comprising a somewhat enlarged collar-like portion encircling the shaft  106  and having a diameter somewhat greater than the diameter of the shaft  106 . Preferably, the plungers  100 ,  102  are fabricated of a rigid thermoplastic material having suitable strength for the purposes described herein. 
   The first plunger  100  is provided with a first sweeper support  112  extending radially outwardly of the first shaft  104  adjacent the first plunger bead  124 . The first sweeper support  112  is provided with a planar first inclined surface  120  and a first sweeper lug  116  extending away from the first inclined surface  120 . The second plunger  102  is provided with a second sweeper support  114  extending radially outwardly of the second shaft  106  adjacent the second plunger bead  126 . The second sweeper support  114  is provided with a planar second inclined surface  122  and a second sweeper lug  118  extending away from the second inclined surface  122 . The sweeper support  112 ,  114  is adapted for fixedly attaching a sweeper as hereinafter described. 
   The first plunger  100  is adapted for slidable communication between the first plunger bead  124  and the first cylindrical portion  78  of the first plunger cradle  74 . The first sweeper support  112  is adapted for slidable communication with the first cradle extension  82 . The first plunger  100  can thus slidably translate within the first plunger opening  86 . Similarly, the second plunger  102  is adapted for slidable communication between the second plunger bead  126  and the second cylindrical portion  80  of the second plunger cradle  76 . The second sweeper support  114  is adapted for slidable communication with the second cradle extension  84 . The second plunger  102  can thus slidably translate within the second plunger opening  88 . 
   A sweeper is a generally U-shaped, platelike body, fabricated of an electrically-conductive material such as steel or copper, comprising a crosspiece  132  having an elongated lug aperture  140  therethrough, and a pair of parallel, spaced-apart sweeper arms  134  extending orthogonally from the crosspiece  132 . Each sweeper arm  134  terminates in a plurality of parallel, spaced-apart sweeper fingers  136 , shown in  FIG. 11  as numbering three per arm  134 . Each sweeper finger  136  terminates in a contact  138  extending orthogonally thereto. The lug aperture  140  is adapted for slidable receipt of a sweeper lug  116 ,  118 . The sweeper  128 ,  130  is attached to the sweeper support  112 ,  114  by inserting the sweeper lug  116 ,  118  into the lug aperture  140  so that the sweeper  128 ,  130  is in cooperative communication with the inclined surface  120 ,  122 , respectively. The sweeper  128 ,  130  is retained against the inclined surface  120 ,  122  by welding, heat deformation of the sweeper lug  116 ,  118 , or other suitable means. 
   The circuit board  160  comprises a platelike, generally rectilinear body comprising a generally conventional printed circuit board substrate material  188 . The circuit board  160  is adapted for slidable insertion into the slots  94 ,  96  parallel to and spaced somewhat away from the rear wall  58 . A plurality of contact strips, conductive leads, and conductive contacts are applied to the substrate material  188  in a conventional manner, such as by sputtering or printing. It will be understood that the circuit board  160 , although shown by example in the drawings as a printed circuit board with conductive/resistive strips on only one side, the circuit board  160  can also have the conductive/resistive strips on both sides of the printed circuit board as would be known to one skilled in the art. 
   The circuit board  160  comprises a first outer contact strip  164  and a first inner contact strip  168  in parallel, spaced-apart juxtaposition along a first edge of the circuit board  160  for cooperative association with the first plunger chamber  70  when the circuit board  160  is inserted into the memory module base  58 . Similarly, the circuit board  160  comprises a second outer contact strip  162  and a second inner contact strip  166  in parallel, spaced-apart juxtaposition along a second edge of the circuit board  160  for cooperative association with the second plunger chamber  72  when the circuit board  160  is inserted into the memory module base  158 . Preferably, the inner contact strips  166 ,  168  comprise an electrically-resistive material whose electrical resistance varies along the length of the strip  166 ,  168 . Preferably, the outer contact strips  162 ,  164  comprise an electrically-conductive material. 
   The first outer contact strip  164  is connected through a connecting lead  170  to the second outer contact strip  162 . The second outer contact strip  162  is connected through a connecting lead  172  to a second conductive contact  174 . The first outer contact strip  164  is also connected through a connecting lead  176  to a first conductive contact  178 . The first inner contact strip  168  is connected through a connecting lead  180  to a first resistive contact  182 , and of the second inner contact strip  166  is connected through a connecting lead  184  to a second resistive contact  186 . The contacts  174 ,  178 ,  182 ,  186 , are connected through suitable electrical wiring passing through the wiring pass-throughs  98  for integration into a wiring harness or other suitable electrical connector for operable communication with the vehicle control system. The contact strips  162 – 168  are adapted for slidable communication with the contacts  138  when the plungers  100 ,  102  are inserted into the plunger chambers  70 ,  72 . The inclination of the sweepers  128 ,  130  due to the inclination of the inclined surfaces  120 ,  122  ensures that the contacts  138  are in suitable electrical communication with the contact strips  162 – 168 . 
   An alternative, preferred embodiment of the circuit board  160  is shown in  FIG. 13  in which like reference numerals are used to identify like elements between the embodiments of the circuit board  160  shown in  FIGS. 12 and 13 , respectively. The embodiments are very similar but differ in that the resistive strips are located as the first and second outer contact strips  162 ,  164  and the conductive voltage strips are provided as the first and second inner contact strips  166  and  168 . The first and second inner contact strips  166  and  168  are interconnected by the common connecting lead  170 . The common circuitry defined by the common connecting lead  170  and the first and second inner contact strips  166  and  168  initiate and terminate in contacts  178  and  184  which are respectively connected to a positive voltage source and ground as indicated in  FIG. 13 . Contacts  182  and  186  are interconnected to a mirror position control unit and supply a signal representative of the position of the mirror with respect to horizontal and vertical axes as is described further herein. 
   A schematic of both of the embodiments in  FIGS. 12–13  is shown in  FIG. 14  wherein like reference numerals are employed to identify elements common to the schematic and the  FIGS. 12–13  embodiments. 
   The memory module cover  142  is a generally rectilinear, plate-like body comprising a circular first plunger aperture  144  and a circular second plunger aperture  146  extending therethrough in spaced-apart juxtaposition for cooperative association with the first plunger chamber  70  and the second plunger chamber  72 , respectively. The memory module cover  142  also comprises a front cover tab  148  for interference-type communication with the front cover slot  62 , a first side cover tab  150  for interference-type communication with the side cover slot  64 , a second side cover tab  152  for interference-type communication with the side cover slot  66 , and a rear cover tab  154  for interference-type communication with the rear cover slot  68 . A pair of rubber seals  156 ,  158  are adapted for liquid-tight insertion into the plunger apertures  144 ,  146 , respectively, and slidable, generally liquid-tight receipt of the shafts  104 ,  108 , respectively, of the plungers  100 ,  102 , respectively. The memory module cover  142  is used to close the chamber  143  after the placement of the plungers  100 ,  102  and the circuit board  160  in the chamber  143  so that the plungers  100 ,  102  extend through the rubber seals  156 ,  158 . 
   The memory module  40  is then slidably inserted into the memory module chamber  42  so that the plungers  100 ,  102  extend through suitable apertures (not shown) in the mounting frame  18  toward the frame side  24  of the glass case  20  and the hook  46  engages the bottom wall  60  to retain the memory module  40  in the memory module chamber  42 . Referring again to  FIG. 4 , the first plunger  100  is aligned with the horizontal pivot axis  39  intermediate the pivot pedestal  38  and the upper jackscrew  32 , and the second plunger  102  is aligned with the pivot pedestal  38  to define a vertical pivot axis  37  orthogonal to the horizontal pivot axis  39  and parallel to the jackscrew axis  36 . The balls  106 ,  110  are then pivotably attached in a generally conventional manner to the glass case  26  so that, when the glass case  20  is pivoted by the extension and retraction of the jackscrews  32 ,  34 , the plungers  100 ,  102  will be urged into and out of the plunger chambers  70 ,  72 , respectively. 
   As an example, referring to  FIG. 4 , if the glass case  20  is tilted about the horizontal pivot axis  39  through the operation of the lower jackscrew  34 , the second plunger  102  will be moved with the tilting of the glass case  20 . As the lower jackscrew  34  is extended, the second plunger  102  will be extended. Conversely, as the lower jackscrew  34  is retracted, the second plunger  102  will be retracted. Similarly, if the glass case  20  is tilted about the vertical pivot axis  37  through the operation of both the jackscrews  32 ,  34 , the plunger  100  will be moved with the tilting of the glass case  20 . The plunger  102  will not be moved since it lies along the vertical pivot axis  37 . As the jackscrews  32 ,  34  are extended, the plunger  100  will be extended. Conversely, as the jackscrews  32 ,  34  are retracted, the plunger  100  will be retracted. 
   With reference now to  FIGS. 9 and 12 , the circuit board  160  is electrically powered by the vehicle&#39;s electrical power system (typically 5-volt, 12-volt or other suitable electrical configuration) so that an electrical current flows across the connecting leads  170 ,  172 ,  176 ,  180  and energizes the contact strips  162 – 168 . While the description herein is with respect to the embodiment of the circuit board  160  in  FIG. 12 , the description can be equally applied to the embodiment for the circuit board  160  shown in  FIG. 13  without departing from the scope of this invention and as would be apparent to one skilled in the art. 
   Current can flow between a pair of inner and outer contact strips, such as the second outer contact strip  162  and the second inner contact strip  166 , through the second sweeper  130 . Thus, current can flow across the second conductive contact  174  through the connecting lead  172  to the second outer contact strip  162 , across the second sweeper  130  to the second inner contact strip  166 , through the connecting lead  184  and across the second resistive contact  186 . As the plungers  100 ,  102  are extended and retracted as described above, the contacts  138  will move along the contact strips, such as the second outer contact strip  162  and the second inner contact strip  166 . Because the inner contact strip  166  comprises a resistive material, as the contacts  138  move along the inner contact strip  166 , the resistance of the inner contact strip  166  will change. Thus, the voltage across the contacts  174 ,  186  will vary with the variation in resistance resulting from the movement of the second sweeper  130  along the second inner contact strip  166 . This voltage can be measured and its value stored, and will correspond to a first selected horizontal and/or vertical tilt position, and a first plunger position. If the reflective element  16  and the glass case  20  have been tilted to a second selected horizontal and/or vertical tilt position, thereby moving the plungers  100 ,  102  to a second plunger position, the tilt actuator assembly  22  can be activated so that the plungers  100 ,  102  are returned to the first plunger position. The tilt actuator assembly  22  can be programmed to stop when the voltages from the positions of the plungers  100 ,  102  match the stored voltage values for the selected horizontal and/or vertical tilt position. 
   The positional memory module  40  described herein comprises a separate module from the tilt actuator assembly  22  so that a mirror assembly  10  can be readily provided with or without the positional memory module  40 . The positional memory module  40  can be optimally positioned relative to the pivot pedestal  38  regardless of the size of the internal mounting frame  18  or the mirror assembly  10 . The use of a separate positional memory module  40  eliminates the necessity of having a combined tilt actuator and positional memory device in a range of sizes for different sized mirror assemblies, as well as the increased design and tooling complexity and costs, including the increased sealing complexity, inherent in a combined tilt actuator and positional memory device. The positional memory module  40  can also be readily removed for repair and/or maintenance without the necessity of removing the tilt actuator assembly  22 , or without the necessity of replacing both the tilt actuator and positional memory device when only the positional memory device needs replacing. 
   While particular embodiments of the invention have been shown, it will be understood, of course, that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings. Reasonable variation and modification are possible within the scope of the foregoing disclosure of the invention without departing from the spirit of the invention.