Remotely controlled mirror assembly and control system therefor

A mirror assembly, comprising:

• a) a reflective surface that is supported with respect to a structure so as to be rotatable about two perpendicular axes;
• b) a pair of hydraulic cylinders, each of which is adapted to rotate the reflective surface about one of said perpendicular axes, and each cylinder being divided into two chambers by a piston, and further including a pair of extensible piston rods having pendant and distal ends, each of which rods is connected at its pendant end to a respective one of the two pistons, and each piston rod being connected at its distal end in such a way as to cause the reflective surface to rotate about one of the two perpendicular axes when its associated piston moves;
• c) a pair of reservoirs associated with each of the two hydraulic cylinders, and each of said four reservoirs containing an incompressible liquid, and each of the reservoirs being in communication with a respective one of the four chambers of the two hydraulic cylinders;
• and
• d) means for temporarily pressurizing at least one of the four reservoirs in order to cause the piston in one of the cylinders to move, whereby the reflective surface may be made to rotate about at least one of its two axes by pressurization of an appropriate one of the four reservoirs.

A mirror assembly, comprising:

• a) a reflective surface that is supported with respect to a structure so as to be rotatable about an axis;
• b) an hydraulic cylinder which is adapted to rotate the reflective surface about said axis, and the cylinder being divided into two chambers by a piston, and further including an extensible piston rod having pendant and distal ends, and the rod being connected at its pendant end to the piston and being connected at its distal end in such a way as to cause the reflective surface to rotate about its axis when the piston moves;
• c) a pair of reservoirs associated with the hydraulic cylinder, and each of the reservoirs containing an incompressible liquid, and each of the reservoirs being in communication with a respective one of the two chambers of the hydraulic cylinder;
• and
• d) means for temporarily pressurizing a selected one of the two reservoirs in order to cause the piston in the associated cylinder to move, whereby the reflective surface may be made to rotate in a desired direction about its axis by pressurization of an appropriate one of the two reservoirs.

A mirror assembly, comprising:

• a) a reflective surface that is supported with respect to a fixed structure, and the reflective surface being supported in such a way as to be rotatable at will about two perpendicular axes;
• b) hydraulic means for selectively rotating the reflective surface to a desired position and normally holding it in a static mode with respect to the fixed structure, said hydraulic means including reservoirs in communication with two hydraulic cylinders, and each of the hydraulic cylinders having a pair of chambers that are separated by a movable piston;
• and
• c) a plurality of check valves arranged in sets and interposed between the reservoirs and the chambers in the cylinders, and each set of check valves comprising two substantially similar valves which are in parallel but oppositely oriented, and each check valve having a resistance to liquid flow that is based upon a biasing force applied by an internal spring, such that liquid flow through a given pair of check valves is permitted into and out of one of the chambers of a given cylinder when the biasing resistance of the check valves has been exceeded, and fluid flow through another pair of check valves is permitted into and out of one of the chambers in the other cylinder when the biasing resistance of its check valves has been exceeded, such that a person may manually grab the reflective surface and apply a torque to it which is sufficient to overcome the biasing resistance of the check valves, whereby the reflective surface may be physically rotated by virtue of manually pushing on the reflective surface until the biasing resistance of the check valves has been overcome, and whereby the reflective surface may be manually moved to a desired position even if the hydraulic means has for some reason become inoperative.

A mirror assembly comprising:

• a) a reflective surface that is rotatable with respect to a fixed structure about an axis;
• b) hydraulic means for causing the reflective means to rotate about its axis when pressurized, said means including a double-acting hydraulic cylinder having two chambers separated by a piston, and including a piston rod that is connected to the piston, and the piston rod extending between the reflective surface and the fixed structure, and further including a pair of reservoirs, each reservoir containing an incompressible liquid, with each of the reservoirs being in communication with a respective one of the two chambers;
• and
• c) means for temporarily applying a pressurized gaseous fluid from a source to a selected one of the two reservoirs, such that the selected one of the two reservoirs will be become pressurized and the chamber associated with the pressurized reservoir will also become pressurized, and such that the piston will be forced to move in the direction of the chamber that is not pressurized, and the reflective surface will be rotated in proportion to the amount of movement of the piston.

A mirror assembly including a reflective surface that is adapted for attachment to a rigid structure, and the assembly being capable of being adjustably oriented by an operator in order that the operator might look at the reflective surface so as to obtain fields of view that he or she might not otherwise have by relying on a direct line of sight, and the reflective surface being occasionally subject to external forces that are not under the control of the operator, comprising:

• a) a structural base configured for rigid attachment to a given structure;
• b) a generally planar member mounted for rotation with respect to the structural base, said rotation being about a first axis;
• c) a reflective surface carried by the generally planar member;
• d) a first hydraulic cylinder extending between the structural base and the generally planar member, said hydraulic cylinder comprising a barrel having forward and rearward ends, and having a movable piston that divides the interior of the barrel into two chambers that are identifiable as forward and rearward chambers, and there being a movable piston rod connected at its pendant end to the piston and extending outwardly from the forward end of the barrel;
• e) a first reservoir of hydraulic fluid that is in communication with the rearward chamber in the first hydraulic cylinder;
• f) a second reservoir of hydraulic fluid that is in communication with the forward chamber in the first hydraulic cylinder;
• g) means for selectively pressurizing a given one of the first and second reservoirs in order to cause longitudinal movement of the piston rod so as to thereby rotate the generally planar member about the first axis;
• and
• h) holding means for normally keeping the piston rod immobile after the generally planar member has been moved by an operator to a desired position, and said holding means being effective to resist the forces that would be transmitted to the piston rod by any small external forces that could be applied to the generally planar member, and said holding means being rendered temporarily ineffective in the event that a sufficiently large external force is applied to the generally planar member, and a small external force being one that introduces a pressure in one of the chambers of less than 3 pounds per square inch, and a sufficiently large external force being one that introduces a pressure in one of the chambers of more than 3 pounds per square inch.

The method of selectively adjusting the orientation of a mirror assembly that is attached to the exterior of the cab of a large vehicle, said vehicle being of the class that includes class 8 trucks, buses, motor homes and tractor/trailer rigs, and the mirror assembly including a generally planar member that carries a reflective surface that is oriented so as to serve as a rearview mirror for the driver of the vehicle, such that the driver might obtain fields of view that he or she might not otherwise have by relying on a direct line of sight, including the steps of:

• a) mounting the mirror assembly so that the reflective surface is capable of being selectively rotated with respect to the vehicle's cab by selectively pressurizing a given one of the two chambers of an hydraulic cylinder and thereby causing movement of an associated piston rod, said piston rod being connected to the generally planar member;
• and
• b) promptly returning the pressurized chamber of the hydraulic cylinder to atmospheric pressure after the reflective surface has been moved to a desired orientation;
• and
• c) stabilizing the reflective surface after it has been moved to a desired orientation by holding the generally planar member against unwanted movement as a result of certain external forces that may be applied to the generally planar member by any device other than said piston rod, wherein the stabilizing step includes placing one of the two chambers of an hydraulic cylinder in communication with a pair of parallel but oppositely oriented check valves which are in communication with a reservoir of hydraulic fluid at atmospheric pressure, said check valves serving as relief valves to permit liquid flow if and when a certain external force is applied to the generally planar member, such that the generally planar member may be physically moved by applying an external force directly to the generally planar member, thereby pushing fluid out of the cylinder through an appropriate check valve and into the reservoir, whereby there will be no damage to any part of the mirror assembly by manually pushing on the generally planar member.