CN108468990B

CN108468990B - Lamp bracket capable of automatically lifting

Info

Publication number: CN108468990B
Application number: CN201810199015.3A
Authority: CN
Inventors: 车艳
Original assignee: Ningbo Zhonghui Information Technology Co ltd
Current assignee: Ningbo Zhonghui Information Technology Co ltd
Priority date: 2018-03-12
Filing date: 2018-03-12
Publication date: 2020-04-17
Anticipated expiration: 2038-03-12
Also published as: CN108468990A

Abstract

The invention discloses a lamp bracket capable of automatically lifting, which comprises a mounting plate for fixing to a mounting position and a hanging plate hung below the mounting plate for hanging a lamp main body, wherein the hanging plate is hung on the mounting plate through a telescopic structure, the telescopic structure comprises a plurality of X-shaped structures which are arranged up and down, each X-shaped structure comprises two connecting rods with the middle parts hinged with each other, the connecting rods of the adjacent X-shaped structures are correspondingly hinged with each other, the upper end parts of the two connecting rods of the X-shaped structure positioned at the top are both provided with sliding sleeves, a sliding rod which is in sliding fit with the sliding sleeve is fixed on the mounting plate, the X-shaped structure at the lowest part is arranged on the hanging plate through a driving structure, the driving structure comprises a screw rod which is arranged on the hanging plate and corresponds to the slide rod, threads with opposite turning directions are arranged on two sides of the screw rod, the lower end parts of the two connecting rods of the lowest X-shaped structure are provided with thread sleeves which are respectively matched with the threads on the two sides of the screw rod. The lamp bracket facilitates the installation and the disassembly of a larger decorative lamp.

Description

Lamp bracket capable of automatically lifting

Technical Field

The invention relates to the field of lamps, in particular to a lamp holder capable of automatically lifting.

Background

Traditional ornament lamp is installed at the ceiling in room, because highly higher often will be with the help of tools such as ladder when installation and repair to the ornament lamp generally all is bulky, and quartzy decoration accessory is more, even if adopt the ladder, the dismouting of ornament lamp is also very inconvenient, and high altitude construction also must bring certain potential safety hazard.

Disclosure of Invention

The invention mainly aims to provide a lamp holder capable of automatically lifting and a lamp.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows: a lamp holder capable of automatically lifting comprises a mounting plate for fixing to a mounting position and a hanging plate hung below the mounting plate for hanging a lamp body, it is characterized in that the hanging plate is hung on the mounting plate through a telescopic structure, the telescopic structure comprises a plurality of X-shaped structures which are arranged up and down, each X-shaped structure comprises two connecting rods with the middle parts hinged with each other, the connecting rods of the adjacent X-shaped structures are correspondingly hinged with each other, the upper end parts of the two connecting rods of the uppermost X-shaped structure are both provided with sliding sleeves, a sliding rod which is in sliding fit with the sliding sleeve is fixed on the mounting plate, the X-shaped structure at the lowest part is arranged on the hanging plate through a driving structure, the driving structure comprises a screw rod which is arranged on the hanging plate and corresponds to the slide rod, threads with opposite turning directions are arranged on two sides of the screw rod, the lower end parts of the two connecting rods of the lowest X-shaped structure are provided with thread sleeves which are respectively matched with the threads on the two sides of the screw rod.

Preferably, the driving structure further comprises a motor mounted on the hanging plate, a first spur gear arranged on an output shaft of the motor, a support shaft rotatably supported on the hanging plate, a second spur gear fixed on the support shaft and engaged with the first spur gear, a differential structure sleeved on the support shaft and having one end fixedly connected with the second spur gear, and a first bevel gear rotatably supported on the support shaft and fixedly connected with the other end of the differential structure, the third straight gear is rotatably supported on the hanging plate and meshed with the first bevel gear, the third straight gear is coaxially and fixedly arranged with the second bevel gear, the transmission shaft is supported on the hanging plate, the axis of the transmission shaft is parallel to that of the third straight gear, the fourth straight gear is fixed on the transmission shaft and meshed with the third straight gear, the third bevel gears are arranged on two sides of the transmission shaft, and the fourth bevel gear is arranged at one end of the screw rod and meshed with the corresponding third bevel gear.

Preferably, the differential structure includes a plurality of differential blocks connected end to end, the differential blocks rotatably support the shaft, one end of the differential block at one end of the differential structure is fixed to the second spur gear, one end of the differential block at the other end of the differential structure is fixed to the first bevel gear, and adjacent differential blocks can relatively rotate within a certain range.

Preferably, each differential block comprises a large circular ring and a small circular ring which are coaxially arranged and connected with each other, the small circular ring of the adjacent differential block can be inserted into the corresponding large circular ring, an inner buckle extending along the axial direction of the large circular ring is arranged on the inner edge of the large circular ring, and an outer buckle matched with the inner buckle and extending along the axial direction of the small circular ring is arranged on the outer edge of the small circular ring.

Preferably, the drive structures have two sets, the two sets of drive structures being arranged symmetrically with respect to each other.

Preferably, the lighting fixture still includes the locking structure of two sets of symmetries settings, and every group the locking structure includes the rack that two symmetries set up, the rack is connected with the back shaft transmission, just is provided with the trip with rack complex in the downside of mounting panel and the position department that corresponds with two sets of locking structures respectively, the position directly over enough of card can be stretched out selectively to the outer tip portion at least of rack.

Preferably, each set of the locking structures further comprises a bracket supported on the hanging plate in a manner of moving up and down, a rotating shaft rotatably supported on the bracket, and sixth spur gears positioned at two ends of the rotating shaft, wherein each sixth spur gear is selectively meshed with a corresponding rack, and the rotating shaft is in transmission connection with the supporting shaft.

Preferably, a compression spring which can enable the sixth straight-tooth wheel to be disengaged from the rack is arranged between the support and the hanging plate, an ejector rod is arranged at a position, corresponding to the support, on the mounting plate, and the ejector rod can enable the sixth straight-tooth wheel to be engaged with the rack when the rack moves upwards to a certain height.

Preferably, the sixth spur gear is rotatably fixed to the rotating shaft, a protrusion is disposed on an outer end face of each sixth spur gear, a snap ring is fixed to a position, corresponding to each sixth spur gear, of the rotating shaft, a protruding strip matched with the protrusion on the sixth spur gear is disposed on the snap ring, a return spring is disposed between the rack and the hanging plate, and the return spring always has an acting force for extending the rack.

Preferably, a coil spring is provided between the sixth spur gear and the rotary shaft, the coil spring always having a force to rotate the sixth spur gear in a direction opposite to a rotational direction in which the sixth spur gear is rotated when the rack gear is extended.

Compared with the prior art, the invention has the following beneficial effects:

the lamp holder is controlled to ascend and descend through the motor, when the lamp body needs to be disassembled and assembled, only the hanging plate needs to be moved downwards to a proper position, and the problems of operation trouble and unsafety caused by high-altitude operation are solved; meanwhile, the form that the rack is matched with the clamping hook is adopted, so that when the lamp main body is normally hung, only the rack needs to be hung on the clamping hook, a telescopic structure and a motor are avoided being always adopted, and the stability during hanging is improved; meanwhile, the differential structure is adopted, when the lamp body needs to be put down, the rack can be retracted firstly, then the telescopic structure starts to extend out, and orderly action is realized.

Drawings

FIGS. 1-3 are block diagrams of different states of use according to a preferred embodiment of the present invention;

fig. 4 is an exploded view of a lamp holder according to the present invention that can be automatically lifted;

FIGS. 5-7 are views illustrating the construction of the connection of the hanging panel with other structures according to a preferred embodiment of the present invention;

fig. 8 is an exploded view of a locking structure of the automatically liftable lamp holder according to the present invention;

FIG. 9 is a view showing the construction of the installation of the transmission structure and the locking structure on the hanging plate according to a preferred embodiment of the present invention;

FIG. 10 is a block diagram of a mounting plate in accordance with a preferred embodiment of the present invention;

fig. 11-12 are block diagrams of a differential block according to a preferred embodiment of the present invention.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

As shown in fig. 1 to 12, the lamp holder capable of automatically lifting comprises a mounting plate 2 for mounting the lamp holder on a mounting position such as a ceiling, a hanging plate 1 for mounting a lamp body, and a telescopic structure 3 for connecting the mounting plate 2 and the hanging plate 1, wherein the telescopic structure 3 can realize the up-and-down movement of the hanging plate 1 relative to the mounting plate 2 so as to move the lamp body to a required position.

Extending structure 3 is for cutting fork extending structure, has two sets ofly, every group all includes many connecting rods 31, two liang of middle parts in a plurality of connecting rods 31 are articulated each other and have been constituted a plurality of X type structures, the both ends of the top of two connecting rods 31 of the X type structure that are located the below of adjacent X type structure and the both ends that correspond of the below of two connecting rods 31 of the X type structure that are located the top are articulated to have constituted deformable parallelogram structure, a plurality of X type structural connection become a plurality of deformable parallelogram structures and then can realize reciprocating of lamp main part through the deformation of parallelogram structure. The two groups of telescopic structures are arranged in parallel.

And, the upper ends of two connecting rods 31 of the uppermost X-shaped structure are both provided with a sliding sleeve 22, a sliding rod 21 corresponding to each group of telescopic structures is arranged on the mounting plate 2, and the sliding sleeve 22 is slidably arranged on the sliding rod 21 to realize the connection of the telescopic structure 3 and the mounting plate 2.

The lower end of the telescopic structure 3 is arranged on the hanging plate 1 through a driving structure 4. The driving structure comprises a motor 43, a first straight gear 44 arranged on an output shaft of the motor 43, a supporting shaft 41 rotatably supported on the hanging plate 1, a second straight gear 45 fixed on the supporting shaft 41 and meshed with the first straight gear 44, a differential structure 46 sleeved on the supporting shaft 41 and fixedly connected with the second straight gear 45 at one end, a first bevel gear 47 rotatably supported on the supporting shaft 41 and fixedly connected with the other end of the differential structure 46, a second bevel gear rotatably supported on the hanging plate 1 and meshed with the first bevel gear 47, a third straight gear coaxially and fixedly arranged with the second bevel gear, a transmission shaft 411 supported on the hanging plate 1 and having an axis parallel to that of the third straight gear, a fourth straight gear fixed on the transmission shaft 411 and meshed with the third straight gear, third bevel gears 412 arranged on two sides of the transmission shaft 411, and two lead screws 414 rotatably supported on the hanging plate 1 and respectively corresponding to the two groups of telescopic structures 3, The fourth bevel gear is arranged at one end of the screw rod 414 and meshed with the third bevel gear 412 on the corresponding side, and the thread sleeves 42 are arranged at the lower ends of the two connecting rods 31 of the lowermost X-shaped structure of the telescopic structure 3 on the corresponding side, threads with opposite rotation directions at two ends are arranged on two sides of the screw rod 414, the thread sleeves 42 below each group of telescopic structure 3 are matched with the threads at the corresponding end on the screw rod 414 on the corresponding side, so that the differential structure 46 can be driven to rotate through the rotation of the motor 43, the rotation of the differential structure 46 drives the rotation of the transmission shaft 411, and the transmission shaft 411 drives the rotation of the screw rod 414 so as to enable the two thread sleeves 42 on the screw rod 414 to move in opposite directions or far away, thereby enabling the parallelogram structure of the telescopic structure 3 to deform to achieve the telescopic structure 3. When the telescopic structure 3 is extended and contracted, the sliding sleeve 22 slides on the sliding rod 21.

Specifically, the differential structure 46 includes a plurality of end-to-end differential blocks 461, the differential blocks 461 include two large rings 462 and small rings 463 which are coaxially arranged and connected with each other, the inner diameter of the large ring 462 is equal to or slightly larger than the outer diameter of the small ring 463, the end-to-end connection of the differential blocks 461 is realized by inserting the small ring 463 of the previous differential block 461 into the large ring 462 of the next differential block 461, and the relative rotation of the differential blocks 461 is realized. The small ring 463 has an inner diameter equal to or slightly larger than the diameter of the support shaft 41 so that the differential block 461 can be supported on the support shaft and the differential block 461 can rotate relative to the support shaft 41.

An inner buckle 464 extending along the axial direction is arranged on the inner edge of the large ring 462, an outer buckle 465 extending along the axial direction is arranged on the outer edge of the small ring 463, when the large ring 462 and the small ring 463 which are matched with each other rotate mutually, the transmission between the differential blocks 461 is realized through the matching of the outer buckle 465 and the inner buckle 464, and because the transmission can be realized only when the outer buckle 465 rotates to the position matched with the inner buckle 464, when the motor 43 rotates, the first bevel gear 47 cannot rotate immediately, and a certain time delay exists.

The locking structures 5 comprise two groups, and the two groups of locking structures 5 are respectively arranged at two ends of the hanging plate 1 along the length direction of the supporting shaft 41. Each set of locking structures 5 includes a fifth bevel gear 512 disposed at one end of the supporting shaft 41, a sixth bevel gear 513 rotatably disposed on the driving shaft 411, an eighth spur gear 516 coaxially fixed with the sixth bevel gear 513, a bracket 51 supported on the hanging plate 1 and positioned directly above the driving shaft 411, a rotating shaft 52 rotatably supported on the bracket 51 and parallel to the driving shaft 411, a fifth spur gear fixed on the rotating shaft 52 and engaged with the eighth spur gear 516, two sixth spur gears 58 rotatably fixed at both ends of the rotating shaft 52, respectively, and a rack 512 supported on the hanging plate 1 and selectively engageable with the sixth spur gears 58.

A protrusion 580 is disposed on an end surface of the sixth spur gear 58, a snap ring 511 is disposed on the rotating shaft 52 at a position corresponding to the protrusion 580, a protruding strip 5111 engaged with the protrusion 580 is disposed on the snap ring 511 along a radially outward direction, and when the snap ring 511 rotates along with the rotating shaft 52, the protruding strip 5111 can drive the sixth spur gear 58 to rotate and further drive the rack 512 to move when moving to the position of the protrusion 580.

Specifically, the rack 512 is supported on the hanging plate 1 through the base 514, and a return spring 515 which is always in a compressed state is arranged between the inner end of the rack 512 and the base 514, so that when the protrusion 580 and the protruding strip 5111 are not matched or the sixth spur gear 58 is not matched with the rack 512, the return spring 515 always enables the protruding strip 5111 to be in an extended state. The base 514 is provided with a guide rail 513 extending along the moving direction of the rack 512, the rack 512 is provided with a guide groove (not shown) matched with the guide rail 513, and through the matching of the guide rail 513 and the guide groove, the rack 512 can not shake during movement.

Two support columns 55 are arranged below the bracket 51, supports 53 corresponding to the two support columns 55 are arranged on the hanging plate 1, a support hole 531 is arranged on each support 53, the support columns 55 can be inserted into the corresponding support holes 531, a compression spring 54 which is always in a compression state is arranged in each support hole 531, the upper end of each compression spring 54 abuts against the lower end face of each support column 55, the lower end of each compression spring abuts against the bottom of each support hole 531, and the compression spring 54 can enable the sixth straight gear 58 to be disengaged from the rack 512 under the effect of no external force.

The below at the both ends of mounting panel 2 is provided with the trip 23 that extends to the inboard with rack 512 selective complex, works as when rack 512 rises to trip 23 top, the outer end of rack 512 can stretch out trip 23 directly over and support and play the effect that supports link plate 1 on trip 23, just so avoid motor 43 still to provide the effort and prevent that extending structure from descending when lamp main part normal use, saved the electric quantity, also guaranteed safe handling.

The push rod 24 extending towards the direction of the bracket 51 is arranged at the position, corresponding to the bracket 51, on the mounting plate 2, when the bracket 51 moves upwards to a certain height, the push rod 24 abuts against the bracket 51, at the moment, the bracket 51 does not move upwards any more, the hanging plate 1 continues to move upwards, and when the hanging plate 1 moves to a certain height, the rack 512 is higher than the clamping hook 23, at the moment, the motor 43 stops rotating, the fifth spur gear is meshed with the eighth spur gear 516, the sixth spur gear 58 is meshed with the rack 512, and the rack 512 extends out of the clamping hook 23 under the action of the reset spring 515 so that the hanging plate 1 is hung on the mounting plate 2 through the rack 512.

In order to enable the return spring 515 to push the rack 512 to extend above the hook 23 without interference of the sixth spur gear 58, an angle between the protrusion 580 and the protruding strip 5111 should be larger than an angle for rotating the sixth spur gear 58 when the rack 512 extends.

Further, in order to secure the size of the angle, a coil spring 56 is provided between the sixth spur gear 58 and the rotary shaft 52, and the coil spring 56 enables the projection 580 to abut on the front side surface of the protruding strip 5111 in the rotation direction of the sixth spur gear 58 when the rack 5111 is extended, which enables to secure not to be interfered by the sixth spur gear 58 when the return spring 515 pushes the rack 512 to be extended. Specifically, in order to reduce friction between the sixth spur gear 58 and the rotation shaft 52, the sixth spur gear 58 is mounted on the rotation shaft 52 through a bearing 510.

Meanwhile, in order to facilitate that the hook 23 and the rack 512 can be automatically matched when the hanging plate 1 moves upwards to a certain height, one of the lower side surface of the hook 23 and the upper side surface of the outer end of the rack 512 is provided with an inclined surface, preferably, the lower side surface of the hook 23 and the upper side surface of the outer end of the rack 512 are provided with inclined surfaces matched with each other, the inclined surfaces are helpful for the buckle 23 to push the rack 512 to retract, and when the rack 512 is higher than the hook 23, the rack 512 extends out of the upper side of the hook 23 under the action of the reset spring 515 so that the hanging plate 1 is hung on the mounting plate 2 through the rack 512.

When the lamp body needs to be moved downwards, the motor 43 rotates reversely, the rotation motion is not transmitted to the screw rod 414 immediately due to the differential structure 46, the support shaft 41 rotates immediately and transmits the rotation motion to the snap ring 511, the snap ring 511 drives the sixth spur gear 58 to rotate due to the matching of the convex strip 5111 and the protrusion 580, the sixth spur gear 58 drives the rack 512 to retract, and when the rack 512 retracts and is not blocked by the snap hook 23, the rotation motion of the motor 43 is transmitted to the screw rod 414, and the screw rod 414 rotates to drive the telescopic structure 3 to extend to realize the descending of the lamp body. And, when it descends to a certain extent, the carrier 51 is no longer acted on by the carrier rod 24, the sixth spur gear 58 is disengaged from the rack 512 by the compression spring 54, the fifth spur gear is disengaged from the eighth spur gear 516, the return spring 515 pushes the rack 512 to be extended to wait for the next engagement with the hook 23, and the protrusion 580 of the sixth spur gear 58 is abutted against the front side surface of the protruding strip 5111 of the snap ring 511 by the coil spring 56 to wait for the next engagement with the rack 512.

A connecting shaft 25 corresponding to the transmission shaft 411 is provided below the mounting plate 2, pulleys 61 are rotatably attached to both ends of the rotating shaft 411, and pulleys 62 corresponding to the pulleys 61 are also provided to both ends of the connecting shaft 25. When the telescopic structure needs to be dismantled or maintained, the corresponding pulley 61 and the pulley 62 can be connected through a rope, so that the hanging plate 1 is slowly put down, namely the pulley 61 can play a role in convenient disassembly.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A lamp holder capable of automatically lifting comprises a mounting plate (2) used for being fixed to a mounting position and a hanging plate (1) used for hanging a lamp body and hung below the mounting plate, and is characterized in that the hanging plate (1) is hung on the mounting plate (2) through a telescopic structure (3), the telescopic structure (3) comprises a plurality of X-shaped structures arranged up and down, each X-shaped structure comprises two connecting rods (31) with the middle parts hinged with each other, the connecting rods (31) of adjacent X-shaped structures are correspondingly hinged with each other, sliding sleeves (22) are arranged at the upper ends of the two connecting rods (31) of the uppermost X-shaped structure, sliding rods (21) in sliding fit with the sliding sleeves (22) are fixed on the mounting plate, the lowermost X-shaped structure is installed on the hanging plate (1) through a driving structure (4), the driving structure comprises lead screws (414) installed on the hanging plate (1) and corresponding to the sliding rods (21), the two sides of the screw rod (414) are provided with threads with opposite rotation directions, the lower end parts of two connecting rods (31) of the X-shaped structure at the bottom are provided with thread sleeves (42) respectively matched with the threads at the two sides of the screw rod (414), the driving structure (4) further comprises a motor (43) arranged on the hanging plate, a first straight gear (44) arranged on an output shaft of the motor (43), a supporting shaft (41) rotatably supported on the hanging plate (1), a second straight gear (45) fixed on the supporting shaft (41) and meshed with the first straight gear (44), a differential structure (46) sleeved on the supporting shaft (41) and fixedly connected with the second straight gear (45) at one end, a first bevel gear (47) rotatably supported on the supporting shaft (41) and fixedly connected with the other end of the differential structure (46), a second bevel gear (48) rotatably supported on the hanging plate (1) and meshed with the first bevel gear (47), and a second bevel gear (48), A third straight gear (49) coaxially and fixedly arranged with the second bevel gear (48), a transmission shaft (411) supported on the hanging plate (1) and having an axis parallel to the axis of the third straight gear (49), a fourth straight gear (410) fixed on the transmission shaft (411) and engaged with the third straight gear (49), third bevel gears (412) arranged at both sides of the transmission shaft (411), and fourth bevel gears (415) arranged at one end of the screw rod (414) and engaged with the corresponding third bevel gears (412), wherein the differential structure (46) comprises a plurality of end-to-end differential blocks (461), the differential blocks (461) are rotatably arranged on the support shaft (41), one end of the differential block (461) at one end of the differential structure (46) is fixed on the second straight gear (45), one end of the differential block (461) at the other end of the differential structure (46) is fixed on the first bevel gear (47), the adjacent differential blocks (461) can relatively rotate in a certain range, each differential block (461) comprises two large circular rings (462) and small circular rings (463) which are coaxially arranged and connected with each other, the small circular rings (463) of the adjacent differential blocks (461) can be inserted into the corresponding large circular rings (462), inner buckles (464) which extend along the axial direction of the large circular rings are arranged on the inner edges of the large circular rings (462), outer buckles (465) which extend along the axial direction of the small circular rings (463) and are matched with the inner buckles (464) are arranged on the outer edges of the small circular rings (463), the lamp holder further comprises two groups of symmetrically arranged locking structures (5), each group of locking structures (5) comprises two symmetrically arranged racks (512), the racks (512) are in transmission connection with the supporting shaft (41), clamping hooks (23) which are matched with the racks (512) are arranged on the lower side of the mounting plate (2) and at positions which respectively correspond to the two groups of locking structures (5), at least the outer end part of the rack (512) can selectively extend to the position right above the clamping hook (23), each group of locking structures (5) further comprises a bracket (51) which can be supported on the hanging plate (1) in a vertically moving mode, a rotating shaft (52) which is rotatably supported on the bracket, and sixth spur gears (58) which are located at two ends of the rotating shaft (52), each sixth spur gear (58) is selectively meshed with the corresponding rack (512), and the rotating shaft (52) is in transmission connection with the supporting shaft (41).

2. An automatically liftable lamp holder according to claim 1, characterized in that the driving structures (4) are provided in two groups, and the two groups of driving structures (4) are arranged symmetrically to each other.

3. The lamp holder capable of automatically lifting according to claim 1, wherein a compression spring (54) capable of disengaging the sixth spur gear (58) from the rack (512) is arranged between the bracket (51) and the hanging plate (1), a push rod (24) is arranged on the mounting plate (2) at a position corresponding to the bracket (51), and the push rod (24) can engage the sixth spur gear (58) with the rack (512) when the rack (512) moves upwards to a certain height.

4. The lamp holder capable of automatically lifting and lowering according to claim 1, wherein the sixth spur gears (58) are rotatably fixed on the rotating shaft (52), a protrusion (580) is arranged on the outer end face of each sixth spur gear (58), a snap ring (511) is fixed on the rotating shaft (52) at a position corresponding to each sixth spur gear (58), a protruding strip (5111) matched with the protrusion on the sixth spur gear (58) is arranged on the snap ring (511), a return spring (515) is arranged between the rack (512) and the hanging plate (1), and the return spring (515) always has an acting force for extending the rack (512).

5. An automatically liftable lamp holder according to claim 4, wherein a coil spring (56) is provided between the sixth spur gear (58) and the rotary shaft (52), and the coil spring (56) always has a force for rotating the sixth spur gear (58) in a direction opposite to a rotation direction of the sixth spur gear (58) when the rack gear (512) is extended.