| CPC A47B 51/00 (2013.01) [A47B 57/06 (2013.01); G05B 19/4155 (2013.01); A47B 2051/005 (2013.01); A47B 2220/0013 (2013.01); G05B 2219/33114 (2013.01)] | 10 Claims |
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1. A moveable shelf system with capability for vertical motion only, comprising:
a control board assembly mounted to a horizontal support structure and comprising:
a control board housing;
at least four reels housed by the control board housing and rigidly attached to substantially horizontal axles which rotate in bearings, wherein a first pair of reels is mounted such as to rotate around parallel axes and a second pair of reels is mounted such as to rotate around axes perpendicular to the axles of the first pair;
a drive motor mounted to the control board housing and configured for simultaneous rotation of the at least four reels by turning the axles to which the reels are fixed;
a microprocessor mounted to the control board housing;
a solenoid latch mounted to the control board housing and controlled by the microprocessor such that when the latch engages teeth of a gear fixed to one axle, the axle is locked, whereby downward motion of the shelf is prevented when electrical power to the drive motor is absent;
a plurality of relays;
a speed controller mounted to the control board housing and controlled by the microprocessor and wherein an output of the speed controller is connected to the drive motor; and
a fuse box mounted to the control board housing;
a moveable shelf hanging below the control board assembly from four belts wherein a first end of each belt is wrapped around one reel and a second end of each belt is coupled to the moveable shelf, whereby the reel rotational axes result in a first pair of belts coupled to the first pair of reels being orthogonal to a second pair of belts coupled to the second pair of reels, whereby the orthogonal planes of the belts inhibit swaying of the shelf in the fore, aft, left, and right positions when the shelf is moved vertically, wherein the system is further configured to move the moveable shelf between an upper position and a lower position by the simultaneous rotating of the four reels, the shelf further comprising a plurality of rubber feet mounted to an underside of the moveable shelf, the shelf further supporting a compressible stop mechanism mounted to the shelf, wherein the compressible stop mechanism contains a spring stiffer than a spring in an up limit switch;
the up limit switch mounted to the control board and in communication with the microprocessor such that a status of the up limit switch is sensed by the microprocessor and contact of the up limit switch with the compressible stop mechanism causes the moveable shelf to stop at the upper position;
a down limit switch in communication with the microprocessor such that a status of the down limit switch is sensed by the microprocessor,
wherein moving from the upper position to the lower position further includes the microprocessor sending a command to the drive motor to raise the shelf a distance smaller than a stroke of the spring of the compressible stop mechanism while simultaneously actuating the solenoid latch to unlock the drive axle, then sending a command to the drive motor to commence downward motion;
at least one sensor coupled to the microprocessor, wherein the at least one sensor provides a real time monitor of vertical velocity with which the microprocessor can exercise feedback control of the acceleration of the shelf up to a target cruising velocity and deceleration back to rest as the shelf approaches a lower or upper terminus of its vertical trajectory;
a push button switch coupled to the microprocessor, whereby momentary depression of the push button switch triggers the movement of the shelf between the upper and lower positions by causing the microprocessor to initiate a sequence of commands to the plurality of relays and the speed controller such that when the shelf is in the upper position, depression of the push button switch causes the shelf to descend to the lower position, and when the shelf is in the lower position, depression of the push button switch causes the shelf to ascend to the upper position, wherein the microprocessor is further configured to, when the shelf is in the upper position and prior to commencing downward motion, send a command to the drive motor to raise the shelf a distance beyond a stop set by the up limit switch while simultaneously actuating the solenoid to unlock the axle.
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