Motor-driven screen roller assembly for automobiles
BACKGROUND OF THE INVENTION 
     The present invention relates to a motor-driven screen roller assembly for installation in an automobile for subdividing the inside space of the automobile, in order to circulate cooling air from the air-conditioner within a defined area inside the automobile. 
     Most users of cars drive the car alone without carrying any passengers. Furthermore, if there is only the driver in the automobile when the air-conditioner of the automobile is operated, energy is wasted by the air-conditioner. If the area around the driver is separated from the remaining inside space of the automobile for circulation of cooling air from the air-conditioner, the working efficiency of the air-conditioner can be relatively improved. 
     SUMMARY OF THE INVENTION 
     It is the main object of the present invention to provide a motor-driven screen roller assembly for automobiles which can be conveniently controlled to subdivide the inside space of the automobile so as to circulate cooling air from the air-conditioner of the automobile within a limited area around the driver. According to the present invention, the motor-driven screen roller assembly is comprised of two motor-driven screen rollers controlled by a FORWARD/STOP/BACKWARD control switch through a selector switch. Each motor-driven screen roller comprises a mounting plate fixed to the ceiling inside an automobile, two reversible DC motors bilaterally fastened to the mounting plate at the bottom, a roller coupled between the reversible DC motors, a screen having one end fixed to the roller and an opposite end coupled to a slat. The FORWARD/STOP/BACKWARD control switch and the selector switch are connected in series between the reversible DC motors of the motor-driven screen rollers and the battery power supply circuit of the automobile. The FORWARD/STOP/BACKWARD control switch operates in cooperation with the selector switch to selectively control the operation of the DC motors of the first motor-driven screen roller or the second motor-driven screen roller. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of a motor-driven screen roller for automobiles according to the present invention; 
     FIG. 2 is an exploded view of the motor-driven screen roller shown in FIG. 1; 
     FIG. 3 is a circuit diagram of the motor control circuit according to the present invention; and 
     FIG. 4 is a perspective view of an alternate form of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a motor-driven screen roller in accordance with the present invention is generally comprised of a power drive 1, a mounting plate 2, and a screen body 3. The power drive 1 comprises two reversible 12 V DC motors 11 and 12. The mounting plate 2 can be made of any of a variety of shapes and sizes to fit the space inside the automobile in which the motor-driven screen roller is to be installed. When the mounting plate 2 is fixedly secured to the ceiling inside the automobile, the DC motors 11 and 12 are bilaterally fastened to the mounting plate 2 on the bottom side thereof by screws. The transparent screen body 3 is preferably made from transparent plastic sheet, having one end fastened to a roller 31 and an opposite end coupled to a slat 32. The roller 31 is connected between the output shafts 110 and 120 of the DC motors 11 and 12, and rotated by them. 
     Referring to FIG. 3 and FIGS. 1 and 2 again, two motor-driven screen rollers may be installed in an automobile, permitting the DC motors 11 and 12 of the first motor-driven screen roller and the DC motors 11a and 12a of the second motor-driven screen roller to be connected to the electric circuit of the automobile through a FORWARD/STOP/BACKWARD switch 4, which can be shifted to control the operation of the DC motors 11 and 12 (the DC motors 11a and 12a) synchronously, and a selector switch 5. The output end of the FORWARD/STOP/BACKWARD switch 4 is connected to the input end of the selector switch 5. The output end of the selector switch 5 has two sets of contacts 51 and 52 respectively connected to the DC motors 11 and 12 of the first motor-driven screen roller and the DC motors 11a and 12a of the second motor-driven screen roller. When the selector switch 5 is shifted to the first set of contacts 51, the DC motors 11 and 12 are connected to the FORWARD/STOP/BACKWARD switch 4, and the DC motors 11a and 12a are disconnected from the FORWARD/STOP/BACKWARD switch 4. When the switch 4 is shifted to FORWARD position, the DC motors 11 and 12 of the first motor-driven screen roller or the DC motors 11a and 12a of the second motor-driven screen roller are synchronously driven to turn the respective roller 31 in one direction, causing it to let out the respective transparent screen body 3. When the switch is shifted to BACKWARD position, the DC motors 11 and 12 of the first motor-driven screen roller or the DC motors 11a and 12a of the second motor-driven screen roller are synchronously driven to turn the respective roller 31 in the reversed direction, causing it to take up the respective transparent screen body 3. When the switch is shifted to STOP position, the DC motors 11 and 12 of the first motor-driven screen roller and the DC motors 11a and 12a of the second motor-driven screen roller are turned off. 
     FIG. 4 shows an alternate form of the power drive 1. According to this alternate form, the power drive comprises a reversible DC motor 13 fastened to one end of the mounting plate 2 at the bottom side thereof to hold one end of the roller 31, a bracket 14 fastened to an opposite end of the mounting plate 2 to hold an axle bearing 15, which holds the opposite end of the roller 31. 
     It is to be understood that various modifications and changes could be made without departing from the spirit and scope of the invention. For example, the DC motors 11 and 12 of the power drive can be directly fastened to the inside of the automobile so that the mounting plate 2 can be eliminated.