Motion control method and apparatus for motorized window blinds and and the like

• US 5,170,108 A
• Filed: 01/31/1991
• Issued: 12/08/1992
• Est. Priority Date: 01/31/1991
• Status: Expired due to Fees

• Current Assignee: Daylighting Incorporated
• Original Assignee: Daylighting Incorporated
• Inventors: Peterson, James E., Collett, Robert W.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US07/648,648
• Time in Patent Office: 677 Days
• Field of Search: 318/250, 318/264, 318/265, 318/266, 318/267, 318/280, 318/282, 318/283, 318/284, 318/285, 318/286, 318/293, 318/466, 318/467, 318/468, 318/469, 318/16, 318/603, 318/626 , 318/628, 49/26, 49/28, 49/348, 49/349
• US Class Current: 318/469
• CPC Class Codes: E05F 15/41 Detection by monitoring transmitted force or torque E05F15/48 takes precedence; Safety couplings with activation dependent upon torque or force, e.g. slip couplings
• CPC Class Codes: E05F 15/603 using rotary electromotors
• CPC Class Codes: E05Y 2800/00 Details, accessories and auxiliary operations not otherwise provided for
• CPC Class Codes: E05Y 2900/00 Application of doors, windows, wings or fittings thereof
• CPC Class Codes: E05Y 2900/106 for garages
• CPC Class Codes: E06B 2009/6836 sensing obstacle
• CPC Class Codes: E06B 2009/6845 sensing position
• CPC Class Codes: E06B 9/32 Operating, guiding, or securing devices therefor operation of tilting bars E06B9/307
• CPC Class Codes: E06B 9/82 automatic
• CPC Class Codes: H02H 7/0851 for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal
• CPC Class Codes: H02H 7/093 against increase beyond, or decrease below, a predetermined level of rotational speed centrifugal switches H01H35/10
• CPC Class Codes: H02P 7/04 by means of a H-bridge circuit

Abstract

A motor controller for reversibly driving a member to be driven along a predetermined path of travel is capable of sensing the speed of the member to be driven and to compare with a predetermined speed level and to adjust the motor drive until the rate of advancement of the driven member corresponds with the predetermined speed level. The motor drive means is completely deactivated if the actual speed should not reach a predetermined start-up threshold within a selected time interval after the motor is initially turned on or should drop beneath the stay-on threshold level which is set beneath the desired speed. The motor drive can also be regulated to run at different reduced or normal speed settings depending upon its intended application.

Claims

1. In motion control apparatus wherein a member is driven along a predetermined path of travel and motor drive means having a maximum speed level is provided for reversibly driving said driven member, the improvement comprising:

speed-sensing means connected to said driven member for sensing the rate of advancement of said driven member along said path of travel and for generating signals proportional to the speed of said driven member;

control means for establishing a predetermined speed level at which said driven member is to be driven, said control means also establishing a minimum speed level in addition to said predetermined speed level, and deactivating means for reactivating said motor drive means when the rate of advancement as sensed by said speed-sensing means is below said minimum speed level, said control means establishing first and second speed levels which define upper and lower limits within which said driven member is to be driven, said upper limit being less than the maximum speed level of said motor drive means;

signal generating means for generating drive signals which are proportional to the signals generated by said speed-sensing means and for driving said motor drive means; and

comparator means for comparing the rate of advancement of said driven member as sensed by said speed-sensing means and the speed levels established by said control means to adjust said drive signals until the rate of advancement of said driven member corresponds with said predetermined speed level.

2. In motion control apparatus according to claim 1, wherein said speed-sensing means rotating at a speed correlated with the rate of advancement of said driven member, and said signal-generating means generating signals in the form of electrical pulses, said comparator means adjusting the width of said electrical pulses until the rate of advancement of said driven member corresponds to said predetermined speed level.

3. In motion control apparatus according to claim 1, wherein said speed-sensing means including a slotted optical disk and a light beam directed across the path of rotation of said disk.

4. In motion control apparatus according to claim 1, wherein said motor drive means includes a reversible DC motor drive, and a bridge circuit for reversing the polarity of said DC motor drive in response to the drive signals received from said signal generating means.

5. In motion control apparatus according to claim 1, wherein said signal-generating means including a switch modulation circuit having a closed feed-back loop connected to said speed-sensing means for modulating the width of said drive signals in the form of electrical pulses for driving said motor drive means.

6. In a motion control system wherein a member is to be driven along a predetermined path of travel and motor drive means is provided for reversibly driving said driven member, said motor drive means being accelerated and decelerated in direct proportion to the width of motor drive pulses received, the improvement comprising:

rotary speed sensing means connected to said driven member for rotation at a speed correlated with the speed of advancement of said driven member along said path of travel, and for generating electrical pulses at a rate corresponding to the rate of advancement of said driven member;

motor drive pulse-generating means for generating the motor drive pulses of a width corresponding to the rate of advancement sensed by said speed sensing means and for driving said motor drive means; and

comparator means electrically connected between said motor drive means and said pulse-generating means for comparing the rate of advancement of said driven member with a predetermined speed level and for adjusting the width of said motor drive pulses until the rate of advancement of said driven member corresponds with said predetermined speed level, said motor drive means including a DC motor drive, and speed control means for modulating power output to said motor drive over a fixed repeating time period in response to the rate of advancement of said member to be driven, said speed control means defined by a pulse width modulation circuit having a closed feedback loop connected to said speed sensing means, and said comparator means having upper and lower speed thresholds to define the boundaries of an acceptable speed range for either normal or reduced speeds.

7. In a motion control system according to claim 6, wherein said speed sensing means includes a slotted optical disk and a light beam directed across the path of rotation of said disk.

8. A method of controlling the speed of advancement of a window shade between open and closed positions and for stopping the movement of the shade in the event of an obstruction, including a drive member for reversibly driving said shade, comprising the steps of:

sensing the rate of advancement of said shade when said drive member is activated;

establishing upper and lower normal speed levels within which said shade is to be advanced by said drive member;

further establishing a minimum speed level below which said drive member is deactivated;

comparing the rate of advancement of said shade with said upper and lower normal speed levels and adjusting the rate of advancement of said shade until it is between said upper and lower normal speed levels; and

deactivating said drive member in the event that the rate of advancement is below said minimum speed level.

9. The method according to claim 8, further including the steps of establishing upper and lower reduced speed levels, comparing the rate of advancement of said shade with said upper and lower reduced speed levels and adjusting the rate of advancement of said shade until it is between said upper and lower reduced speed levels.