Patent Publication Number: US-6220727-B1

Title: Reflective mechanism for a computer-controlled stage lamp

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a reflective mechanism for a computer-controlled stage lamp including universally rotatable motors to provide more colorful light effect. 
     2. Description of the Related Art 
     Sound effect and light effect are very important to stage performance. A good light effect provides a good background to the whole performance and makes the audience focus on the performer(s). A wide variety of stage lamps have heretofore been designed to provide desired light effect. A typical stage lamp, as shown in FIGS. 9 and 10 of the drawings, includes a computer-controlled lamp  6  with a light source (not shown) and a rotating disc (not shown) carrying various patterns thereon mounted in a casing  60  thereof. Light from the light source passes through a pattern on the rotating disc and a lens  61  and is thus incident to a reflective mechanism  7  from which the incident light is reflected, thereby providing colorful reflective images. The reflective mechanism  7  is mounted in a mounting section  62  of the casing  60  and includes a first motor  70  with an output shaft  701  extended through an inclined plate  63 . A bracket  71  is securely attached to the output shaft  701  of the first motor  70  to rotate therewith. A second motor  72  is mounted to the bracket  71  and has an output shaft  721  to which a barrel  74  is mounted. A cylindrical mirror  74  means  741  (consisting of a plurality of mirror strips) is mounted to an outer periphery of the barrel  74  for reflecting incident light from the lens  61 . The inclined plate  63  includes an opening  64  through which a wire  73  extends so as to be electrically connected to the second motor  72  for supplying power to the second motor  72 . The output shaft  701  of the first motor  70  rotates about an axis X, and the output shaft  721  of the second motor  72  rotates about another axis Y that is perpendicular to the axis X. Thus, the barrel  74  with the cylindrical mirror  741  is expected to rotate universally such that the light, after passing through the lens  61 , may be reflected by the mirror  741  to provide varying three-dimensional light images. 
     Nevertheless, rotational movements of the motors  70  and  72  must be limited to avoid entanglement of the wire  73  extended through the opening  64 . In fact, the output shaft  701  of the motor  70  rotates in an interrupted way through a limited angle in opposite directions alternately instead of 360° rotation. In addition, the wire  73  tends to wear by peripheral edge of the opening  64  and thus results in a short circuit or open circuit. In addition, the first motor  70  has a relatively large load (the output shaft  701  carries the bracket  71 , the second motor  72 , and the barrel  74 ) and thus has a short life. 
     The present invention is intended to provide an improved reflective mechanism to solve these problems. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a reflective mechanism for a computer-controlled stage lamp that includes two universally rotatable motors to provide more colorful light effect and to lengthen the life of the motors. 
     In accordance with the present invention, a reflective mechanism is provided for a stage lamp providing an incident light. The reflective mechanism comprises: 
     a first motor having a first output shaft rotating about a first axis; 
     a second motor having a second output shaft rotating about a second axis that is parallel to the first axis; 
     a support drivable by the first output shaft to rotate about the first axis; 
     a barrel carrying a reflective mirror means mounted therearound for reflecting the incident light from the stage lamp, the barrel being mounted to the support and rotatable about a third axis that is perpendicular to the first axis; and 
     means for transmitting power from the second output shaft to the barrel. 
     The stage lamp includes a casing with a mounting section in which the reflective mechanism is mounted. The mounting section of the casing includes an inclined plate. A fixing board is securely attached to the inclined plate. The first motor and the second motor are attached to the fixing board with the first output shaft and the second output shaft extended through the fixing board. An axle includes a first end coaxially engaged with the first output shaft to rotate therewith and a second end that extends through the support to operably engage with the barrel and thus drive the barrel. 
     In an embodiment of the invention, a gear seat is securely engaged to the second end of the axle. A first bevel gear is securely mounted to the gear seat to rotate therewith. The barrel includes a second bevel gear mounted to a side thereof and meshed with the first bevel gear such that rotation of the first output shaft causes rotation of the barrel about the third axis. The second output shaft includes a transmission gear coaxially engaged thereon to rotate therewith. A dry bearing is mounted around the axle. A follower gear is mounted around the dry bearing and securely engaged with the support to rotate therewith. An endless toothed belt is provided for transmitting power from the transmission gear to the follower gear. 
     The fixing board includes a side extension to which a detection board is securely attached. The detection board includes an infrared interrupter on an end thereof A sensor board is mounted around the axle and includes a notch defined in a peripheral edge thereof, the notch being within a detection range of the infrared interrupter. When the power supply to the reflective mechanism is shut off and restarted, the infrared interrupter on the detection board detects position of the notch on the sensor board relative to the infrared interrupter and then sends a feed-back signal to “zero” the output shaft of the motor. New operation modes can be activated according to the programs. 
     In another embodiment of the invention, the barrel is rotatably supported by a shaft, a first belt-driven wheel is securely mounted to the shaft to rotate therewith, and a second belt-driven wheel is securely engaged to the second end of the axle to rotate therewith. A transmission belt is wound around the belt-driven wheels, and a freely rotatable guide roller is provided to guide direction of the transmission belt. 
    
    
     Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a computer-controlled stage lamp with a reflective mechanism in accordance with the present invention. 
     FIG. 2 is a side view of the computer-controlled stage lamp in accordance with the present invention. 
     FIG. 3 is a top view of the computer-controlled stage lamp in accordance with the present invention. 
     FIG. 4 is a longitudinal view of the computer-controlled stage lamp in accordance with the present invention. 
     FIG. 5 is an exploded perspective view of the reflective mechanism in accordance with the present invention. 
     FIG. 6 is a sectional view taken along line  6 — 6  in FIG.  4 . 
     FIG. 7 is a top view illustrating a modified embodiment for transmitting power to a barrel of the reflective mechanism. 
     FIG. 8 is a side view of a portion of the stage lamp with the modified embodiment in FIG. 
     FIG. 9 is a side view, partly sectioned, of a computer-controlled stage lamp with a conventional reflective mechanism. 
     FIG. 10 is a top view, partly sectioned, of a portion of the conventional reflective mechanism in FIG.  9 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIGS. 1 through 8 and initially to FIGS. 1 through 3, a reflective mechanism  2  in accordance with the present invention is mounted in a casing  10  of a computer-controlled lamp  1 . As illustrated in FIG. 4, the computer-controlled lamp  1  generally includes a fan  11 , a light source  12 , a rotational disc  16  carrying patterns thereon, and a lens  17 . The rotational disc  16  is mounted to an output shaft (not labeled) of a motor  15  which, in turn, is mounted to a board  14  with a conic hole  141 . A through-hole  131  is defined in a bracket  13  in the casing  10 . The pattern on the rotational disc  16  is located between the through-hole  131  and the conic hole  141 . Thus, light from the light source  12  passes through the through-hole  131 , the pattern on the rotational disc  16 , and the conic hole  141  and then transmits through the lens  17  and thus is incident to the reflective mechanism  2  that reflects the incident light to the stage. 
     The reflective mechanism  2  is mounted to an inclined plate  181  in a mounting section  18  of the casing  10 . Referring to FIGS. 4 and 5, the reflective mechanism  2  includes a power means  20  consisting of two motors  23  and  27  mounted juxtaposed to each other. As illustrated in FIGS. 5 and 6, a fixing board  21  includes a number of positioning pegs  22  attached thereto, each positioning peg  22  having a first threaded end and a second end with a screw hole (not shown). The first threaded end of each positioning peg  22  is threadedly engaged with the fixing board  21  and the second end of each positioning peg  22  bears against a face of the inclined plate  181 . A screw  221  (FIG. 4) is provided to engage with the screw hole in the second end of each positioning peg  22  to thereby securely attach the fixing board  21  to the inclined plate  181 . The motors  23  and  27  are mounted to the fixing board  21  side by side such that the output shaft  231  of the motor  23  and the output shaft  271  of the motor  27  are parallel to each other. 
     Referring to FIGS. 4 through 6, an axle  24  includes a first enlarged end with a screw hole  241  that is coaxially and threadedly engaged with the output shaft  231  of the motor  23  to rotate therewith. A washer  244  and a sensor board  25  are securely mounted around the axle  24 . A dry bearing  243  is mounted around the axle  24  and a follower bearing  26  is mounted around the dry bearing  243 , best shown in FIG.  6 . The axle  24  further includes a threaded second end  242 , which will be described later. A transmission gear  28  is coaxially engaged with the output shaft  271  of the motor  27  to rotate therewith. The transmission gear  28  is connected with the follower gear  26  via an endless toothed belt  29  such that rotation of the transmission gear  28  causes rotation of the follower gear  26 . A detection board  50  is secured to a side extension  211  of the fixing board  21 . An infrared interrupter  51  is mounted to an end of the detection board  50 . The sensor board  25  includes a notch  251  in a peripheral edge thereof The peripheral edge of the sensor board  25  is within the detection range of the infrared interrupter  51 . 
     As illustrated in FIGS. 4 through 6, the axle  24  and the follower gear  26  extends beyond the inclined plate  181  (FIG.  6 ), wherein the second threaded end  242  of the axle  24  extends beyond a hole  31  (FIG. 5) of a support  30  for threadedly engaging with a screw hole  441  of a gear seat  44  (FIG.  5 ). A washer  442  is mounted around the second threaded end  242  of the axle  24 . A bevel gear  43  is securely mounted to the gear seat  44  by bolts  440  to rotate therewith. Thus, rotation of the output shaft  231  of the motor  23  causes rotation of the bevel gear  44  via transmission of the axle  24  and the gear seat  44 . Rotation of the output shaft  271  of the motor causes rotation of the support  30  via transmission of the gears  26  and  28  and the belt  29 , since the support  30  is securely attached to the follower gear  26  by bolts  33  to rotate therewith. 
     Still referring to FIGS. 4 through 6, a barrel  40  is rotatably mounted to the support  30 . In this embodiment, the barrel  40  includes reflective mirror strips  41  attached to an outer periphery thereof to thereby form a cylindrical reflective mirror means. A bevel gear  42  is formed on at least one end of the barrel  40 . A bearing seat  47  and a bearing  46  are mounted in one of the bevel bears  42 , and a shaft sleeve  48  is mounted in the other bevel gear  42 . A shaft  45  is extended through the bearing  46  and the shaft sleeve  48  with two ends of the shaft  45  inserted into notches  32  (FIG. 5) in two limbs of the support  30 , thereby allowing rotational movement of the barrel  40  relative to the support  30 . Copper rings  481  and a nut  482  are provided to the other end of the shaft  45  to thereby retain the shaft  45  in place. As illustrated in FIG. 6, teeth  421  of one of the bevel gears  42  mesh with teeth  431  of the bevel gear  43 . Thus, rotation of the output shaft  231  of the motor  23  causes rotation of the barrel  40  carrying the reflective mirrors  41  via transmission of the axle  24  and the bevel gears  43  and  42 . As a result, the barrel  40  carrying the reflective mirror strips  41  rotates about an axis Y Rotation of the output shaft  271  of the motor  27  causes rotation of the support  30  via transmission of the gears  26  and  28  and the belt  29 . As a result, the barrel  40  carrying the reflective mirror strips  41  rotates about an axis X that is perpendicular to the axis Y, best shown in FIG.  6 . 
     When the power supply to the reflective mechanism  2  is shut off and restarted, the infrared interrupter  51  on the detection board  50  detects position of the notch  251  on the sensor board  25  relative to the infrared interrupter  51  and then sends a feed-back signal to “zero” the output shaft  231  of the motor  23 . New operation modes can be activated according to the programs. 
     According to the above description, it is appreciated that the barrel  40  carrying the reflective mirror means may rotate universally to provide more colorful light images. Each motor  23 ,  27  operate independently and thus has a longer life. The zeroing design allows the stage lamp to provide expected light images. The performance effect is improved, since the performers may control the light effect. 
     FIGS. 7 and 8 illustrates a modified embodiment for transmitting power to the barrel  40  carrying the reflective mirror strips  41 . The bevel gears  42  and  43  and corresponding elements in the first embodiment have been omitted. Instead, in this embodiment, a belt-driven wheel  80  is mounted around the shaft  45  to rotate therewith. Another belt-driven wheel  82  is securely engaged with the second end  242  of the axle  24  to rotate therewith. A freely rotatable guide roller  84  is provided to guide direction of a transmission belt  86  that is wound around the belt-driven wheels  80  and  82 . 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.