Abstract:
A motorized mirror actuator is disclosed which includes a movable ramp having upwardly facing angled surfaces for urging a cam element in and out of the normal viewing position, thereby moving the rear view mirror into a position which will enable the driver to see his blind spot. A small electric motor is sufficient to drive the mirror in and out of the appropriate angle for viewing the “blind spot” for the driver of the vehicle.

Description:
This application claims the benefit of provisional application No. 60/081,548 filed Apr. 13, 1998. 
     This invention relates generally to a vehicle mirror actuator, and more particularly relates to a motor actuator to adjust the reflective surface of an adjustable vehicle mirror designed to reduce the effects of blind spots in the viewing field of a vehicle driver. 
    
    
     BACKGROUND OF THE INVENTION 
     Problems with seeing objects and/or pedestrians located within the blind spots out of rearview mirrors are well known to drivers. The knowledge of what is located in the “blind spot” of a driver must be learned by movement of the head in combination with looking in the side mounted and windshield mounted rearview mirrors. In order to utilize the same mirror for normal viewing as for blind spot viewing, the mirror must be adjustable. However, conventional adjustable mirrors are four-way mirrors on dual-orthogonality axes, i.e. mirrors that can focus right and left, or up and down. Regrettably, these mirrors are designed to be merely adjustable to accommodate various sizes of drivers. All drivers must be accommodated, and it is well known that men and women are generally of different sizes, so the mirrors need to be adjusted for different drivers. 
     However, these adjustment mechanisms do nothing to alleviate the problem of viewing the “blind spot”. There have been a few proposed solutions for automatically momentarily focusing a rearview mirror to visually cover the entire field of sight, including the “blind spot”. In order to effect such an adjustment, some solenoid adjustment systems have been constructed to temporarily adjust a second mirror or the regularly used side mounted rear view mirror to view the blind spot. But they were not absolutely effective to automatically adjust for blind spot sight because they caused vibration of the reflecting surface. The driver would have to look through a “bouncy” mirror, which would not give a perfect reflection of the blind spot. 
     Such prior art attempts to overcome the problem with viewing “blind spots” have included, among many others, U.S. Pat. No. 5,189,561 issued to Hong on Feb. 23, 1993 which discloses an automatic oscillating vehicle side mirror utilizing a solenoid with an operating lever to actuate the movement of the mirror for the elimination of a blind spot; and U.S. Pat. No. 5,159,497 issued to Lynas on Oct. 27, 1992 which also discloses a rearview mirror for covering the blind spot, although it is also actuated by a solenoid. Both of these prior art patents disclose actuator systems that inherently introduce an element of vibration to the mirror which is undesirable. Other attempts have tried the use of separate mirrors, i.e. U.S. Pat. No. 5,052,792, issued Oct. 1, 1991 to McDonough, which discloses a solenoid actuator means for positioning a second mirror to cover the “blind spot” prior to or during lane changes, turns, or backing maneuvers. 
     It would therefore be desirable to provide an actuation mechanism for the side-mounted rearview mirror which could momentarily and reliably shift the focus of the rearview mirror into the blind spot without vibration, followed by returning to the normal rearwardly focused position for continuous driving. 
     It would also be desirable to provide such an actuation mechanism that utilized as few parts as possible, in order to render the manufacturing process to be as simple as possible, with few parts to fail. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, there is disclosed an electrically driven motorized rearview mirror actuator for a mirror designed to alleviate “blind spots”. The present actuator provides substantially vibration-free movement between the normal driving position and that of a blind spot viewing position for the rearview mirror. The present motorized mirror actuator is made with a relatively few number of parts which will resist a lifetime of movements without wearing out. The present actuator is also a separate actuation means from the standard mirror adjuster which would adjust the mirror from left to right or up and down to accommodate differently sized passengers. Rather, the present actuator is its own actuation means used to rotate the rearview mirror about an axis of rotation which is at a predetermined angle from the normal driving position. 
     In the preferred embodiment, the return of the mirror to its normal position is accomplished without the use of additional motors. This is a great advantage over the prior art. Rather, by the utilization of a well placed spring mechanism, the mirror is returned automatically after being moved into position by the electrically driven motor actuator. Moreover, a delay timer or any other feasible means for timing the action may be used to assure that the mirror is automatically returned to its normal driving position after the driver has had a sufficient amount of time to view the blind spot. The return should generally be accomplished within a time period of between about one second and about three seconds. 
     By utilizing an adjustable positioning mechanism, a conventional singular rear view mirror plate attached to the motorized mirror actuator in accordance with the present invention will move the mirror plate within the rear view mirror housing temporarily between the normal rear view mirror position as desired by the operator of the vehicle, and a preselected “blind spot” position to increase safety of operation. As disclosed in prior art patents, the actuation may be activated by the turn signal, or any other feasible means. If my motorized mirror actuator is in electrical communication with the turn signal, then the problem of viewing the “blind spot” when making a lane change or turn is automatically covered, as the driver will activate the “blind spot” mirror position as soon as he turns on his turn signal. If the driver wants to turn to the left, then the left side would be activated, while the right mirror would be activated during a turn to the right. Needless to say, there are many more ways to effectively activate my actuator, including buttons, levers or knobs located within easy reach of the driver. The trigger mechanism can be anything that works well. The activation means may include a switch on the steering column. 
     Having briefly summarized the invention, it will now be described in greater detail hereinbelow, in the context of the appendant drawings. It is to be noted that the scope of the invention shall only be limited by the appended claims. It is also to be noted that the appended drawings illustrate only typical embodiments of the present invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally fine and effective embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a movable mirror base shown in a perspective view; 
     FIG. 2 is a perspective view of a movable ramp made in accordance with the present invention; 
     FIG. 3 is a front elevational view of a front stationary actuator plate; 
     FIG. 4 is a front elevational view of a back stationary actuator plate; 
     FIG. 5 is a side view of one of the embodiments of the actuation mechanism; 
     FIG. 6 is an end view of the mechanism in accordance with FIG. 5; 
     FIG. 7 is a perspective view of another embodiment of this invention; 
     FIG. 8 is a perspective view of another embodiment of the movable ramp; 
     FIG. 9 is a side view of the second embodiment of the present invention as shown in FIGS. 7 and 8; 
     FIG. 10 is an end view of the same embodiment as FIG. 9; 
     FIG. 11 is an electrical circuit schematic diagram; and 
     FIG. 12 is a graph of current vs. time illustrating the motor brake effectuation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In accordance with the present invention, one of the preferred embodiments is shown in FIGS. 1 through 4, using like numbers for the same parts in all the drawings. Looking first to FIG. 1, there is shown a movable mirror base generally denoted by the numeral  10  including an integral hinge  12 . A spring locator indentation  14  is shown here as a receptor for a beehive spring, although there are many different types of springs which are useful for this purpose. Motor  16  is shown having an elongated jackscrew  18  extending therefrom as being engagingly connected to driver nut  30  which is located within the guideway of movable ramp  20 . T-end  22  is attached to T-bar extension  24  to form a cam element T-bar. The T-bar may be permanently affixed or formed out of the movable mirror base place. The T-bar cammingly communicates with the guideway of the movable ramp. The T-bar slides up and down against the upwardly facing angled or inclined surfaces, which acts to move the mirror in and out of the normal viewing position. As will be seen later with reference to other Figures, the mirror base may be automatically returned to the normal viewing position by a spring located close to the hinge. The hinge (not shown in this Figure) is received in the spring locator indentation and is preferably close to the hinge for two reasons. The first reason is because it minimizes vibration from the hinge and the second reason is because it returns the motor. A boot  26  may be used to help dampen vibration and is illustrated behind the movable ramp  20 . Boot  26  also acts to surround the T-bar extension  24 . Optional heater elements  28  are shown on the back of the base, and may be connected to the remainder of the heater element assembly. 
     Looking now to FIG. 2, there is shown a perspective view of one of the preferred embodiments of the movable ramp generally denoted by the numeral  20 . Movable ramp  20  includes an upwardly facing angled or inclined surface  32  upon which the T-bar (shown in FIG. 1) will ride up and down. Further shown is the guideway  34  which receives the driver nut (again shown in FIG.  1 ). The preferred angle for the inclined surface is 45°, although other angles are feasible. The angle of 45° is especially preferred, though, because this angle allows for a 1:1 relationship, which allows the use of a single spring to return the mirror base. This means that the motor does not need to be reversible, thereby minimizing parts used in the manufacture. Additional motors or a reversible motors may also be used. 
     Referring now to FIG. 3, there is shown a stationary actuator front plate generally shown as numeral  40 . A motor recess  42  is shown for housing the motor extending outwardly from the mirror base  10  as illustrated in FIG.  1 . The concentric circular indentations act to mate with similar indentations in the other half of the “clamshell” as shown in the yet to be discussed FIG.  4 . FIG. 4 shows the stationary actuator back plate  50 , which is designed to mate to the front plate. Hinge protrusions  52  interconnect with the hinge protrusions of FIG. 2, and a hinge pin is dropped between the two sets of hinge protrusions to yield the hinge necessary for rotating the mirror on its axis. 
     Rotation about the hinge formed by the hinge protrusions of the mirror base  10  of FIG. 1, along with the hinge protrusions  52  of the stationary actuator back plate  50  of FIG. 4, works to move the mirror from a normal viewing position to that at the “blind spot” viewing position. The angle of the hinge is from about 1° to about 10° off vertical, although the most preferred and effective angle appears to be about 7° off vertical. Of course, with another mirror configuration, other angles would be more feasible. 
     FIG. 5 is a side view of the entire assembled mirror base  10 , and illustrates the relative positions of the motor  16 , jackscrew  18 , and the movable ramp  20 . The T-end driver  22  is shown connected to the T-driver bar extension  24 . The driver nut  30  moves up and down on the jackscrew  18  which, in turn, moves the movable ramp  20 . As the movable ramp is pulled downwardly, i.e. toward the motor  16 , by the cam relationship between jackscrew  18  and nut  30 , the T-end driver  22  is drawn up the ramp, which essentially pushes down the mirror glass  54  and the mirror base  52  to which it is attached. FIG. 6 shows an end view of FIG. 5, in which it can be seen that ramp  20  works with the driver  22  as it is being guided by guideway  34 . Hinge  12  is shown near spring  15 , which in this case is a beehive spring. 
     FIG. 7 shows yet another embodiment of the same invention, although it can be seen from the drawing that the movable ramp has been turned around, such that the upwardly facing inclined surface is facing toward the mirror base plate, rather than away from it. The new movable ramp  70  is shown with the T-driver bar riding on the surface on the inside between the ramp  70  and the T-driver bar extension. 
     FIG. 8 illustrates the new movable ramp discussed in FIG. 7, generally denoted by numeral  70 , in which an upwardly facing inclined surface  72  is also on the diagonal similar to the movable ramp of FIGS. 1 and 2, discussed above. Similarly, the appropriate angles may be the same as described above. Also similarly, a nut driver guideway  74  is shown recessed within the movable ramp  70  for working cooperatively with the driver nut  30 . 
     FIG. 9 shows a side view of the embodiment shown in FIGS. 7 and 8. As can be seen from the drawing, motor  16  rotates jackscrew  18  within driver nut  30 , which is in turn held within guideway  74  of movable ramp  70 . This urges inclined surface  72  against the tip of the T-driver bar extension  24 , thereby pushing away the mirror base  52  and mirror glass  54 . FIG. 10 shows an end view of the embodiment of FIG. 9, and illustrates the location of the spring  15  with relation to the hinge  12 . The mirror base  52  and the attached mirror glass plate  54  will be returned by the spring  15  toward the actuator plate  50 . Movable ramp  70  is shown in a slidably connected situation under cover  100 . 
     FIG. 11 is the electrical schematic diagram for the motor  16 . As one of ordinary skill in the art will recognize, a normal motor will heat up under “stall reconditions”, such as will occur frequently during the normal operation of the above described invention. This heating up of the motor would prove to be detrimental to the life of the motor. Therefore, in the diagram, the uppermost thermal resistor is a 0.1 ohm resistor during cold operation, so the current will choose this route when it is cold because electricity will follow the path of least resistance. When hot, the resistance increases to 1000 ohms, shifting the electrical path to the five (5) ohm resistor path, which is the lower of the two resistors at that time. The 5 ohm resistance will still leave enough torque in the motor without burning it up in the process. Obviously, similarly smaller and larger resistances are possible to perform the same objective. The diode acts as a motor brake which smooths the return, otherwise it will come back too fast. FIG. 12 is a graphical depiction of the output of current as a function of time when analyzing the electrical circuitry as shown in FIG.  11 . 
     INDUSTRIAL APPLICABILITY 
     The present invention is industrially applicable in the field of rear-view mirrors, especially ones mounted onto or in motor vehicles. Blind spot mirrors have been proposed by other inventors, but were defective in that they used ineffective motors, such as solenoids, for moving the mirrors between the normal and blind spot viewing positions. Therefore, the present invention finds especial industrial applicability in activating blind-spot alleviating side-mounted rear view mirrors for passenger cars.