BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an assembled view showing the external appearance of the first embodiment of the present invention;
FIG. 2 is a schematic assembled view showing the bottom of the driving means of the first embodiment of the present invention;
FIG. 3 is a longitudinal cross-sectional view showing the assembling of the first embodiment of the present invention;
FIG. 4 is a cross-sectional along the line 4-4 in FIG. 3;
FIG. 5 is a cross-sectional view showing the using state of the first embodiment of the present invention;
FIG. 6 is an assembled view showing the external appearance of the second embodiment of the present invention;
FIG. 7 is a longitudinal cross-sectional view showing the assembling of the second embodiment of the present invention;
FIG. 8 is an assembled view showing the external appearance of the third embodiment of the present invention; and
FIG. 9 is a longitudinal cross-sectional view showing the assembling of the fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The characteristics and the technical contents of the present invention will be described with reference to the following detailed description and the accompanying drawings. However, it should be understood that the drawings are illustrative but not used to limit the scope of the present invention.
With reference to FIGS. 1 to 4, the present invention provides a lifting device having parallel double screw rods. The lifting device is connected respectively to a first sliding unit 5, a second sliding unit 6 and a third sliding unit 7 interconnecting with each other so as to control the relative sliding movement among each sliding unit 5, 6, 7. The lifting device comprises a driving means 10, a first transmission means 20 and a second transmission means 30. The driving means 10 is fixedly connected to the bottom of the first sliding unit 5, and it comprises a motor 11 and a base body 12 for fixedly accommodating the motor 11. A transmission shaft 111 protrudes outwardly from the center of the motor 11. The transmission shaft 111 in this embodiment is a worm. The base body 12 is constituted of an upper casing plate 121 fixedly connected to the bottom of the first sliding unit 5 and a lower casing plate 122 covered under the upper casing plate 121.
The first transmission means 20 comprises a screw rod 21, a first gear 22, a telescopic tube assembly 23 and a connecting piece 24. On end of the screw rod 21 penetrates into the base body 12 of the driving means 10 and is fixed on the base body 12 via a bearing or shaft sleeve. The first gear 22 can be a worm gear, and it is connected to one end of the screw rod 21 to rotate with the screw rod 21. The first gear 22 is driven by means of the transmission shaft 111 of the driving means 10. The telescopic tube assembly 23 comprises a telescopic tube 231 and a nut 232 fixedly connected to one end of the telescopic tube 231. The nut 232 is threadedly connected on the screw rod 21 to drive the telescopic tube assembly 23 to linearly move relative to the screw rod 21. The other end of the telescopic tube 231 is fixedly connected to the distal end of the second sliding unit 6 via a connecting piece 24.
The second transmission means 30 is provided at one side of the first transmission means 20 and is parallel thereto. The second transmission means comprises a sleeve 31, a second gear 32, a telescopic tube assembly 33, a screw rod 34 and a connecting rod 35. The bottom of the sleeve 31 is connected to one end of the connecting rod 35. The other end of the connecting rod is connected to the second gear 32, and is fixedly accommodated within the base body 12 of the driving means 10 via a lower bearing 36. The second gear 32 can be a worm gear. The second gear of the second transmission means and the first gear 22 of the first transmission means 20 are simultaneously engaged with and thus transmitted by the transmission shaft 111 of the driving means 10, so that the sleeve 31 can rotate relative to the first sliding unit 5. Further, the inner wall of the sleeve 31 is provided with a plurality of guiding grooves 311 parallel to each other (as shown in FIG. 4).
The telescopic tube assembly 33 comprises a telescopic tube 331 and a nut 332 and a positioning plug 333 fixedly connected to both ends of the telescopic tube 321. The nut 332 is fixed on the connecting piece 24 of the first transmission means 20 via an upper bearing 37. The outer periphery of the positioning plug 333 is provided with a plurality of guiding rails 334 for mating with the guiding grooves 311, so that the telescopic tube assembly 33 can rotate with the sleeve 31 simultaneously. The screw rod 34 is threadedly connected with the nut 332 of the telescopic tube assembly 33. Further, the rotation of the telescopic tube assembly 33 can drive the screw rod 34 to linearly move relative to telescopic tube assembly. The distal end of the screw rod 34 is fixedly connected on the third sliding unit 7.
With reference to FIG. 5, it is a cross-sectional view showing the using state of the first embodiment of the present invention. The lifting device of the present invention can be mounted on an electric table or an electric bed. In use, the rotation of the transmission shaft 111 of the motor 11 simultaneously drives the screw rod 21 of the first transmission means 20 and the connecting rod 35 of the second transmission means 20 to rotate. The screw rod 21 can make the telescopic tube assembly 23 threadedly connected to the screw rod to linearly protrude, so that the connecting piece 24 fixedly connected to the distal end of the telescopic tube 231 and the second sliding unit 6 can protrude relative to the first sliding unit 5. Further, the connecting rod 35 drives the sleeve 31 of the second transmission means 30 to rotate. With the guiding engagement between each guiding groove 311 of the sleeve 31 and each guiding rail 334 of the positioning plug 333, the telescopic tube assembly 33 can axially move relative to the sleeve 31 when the telescopic 33 rotates together with the sleeve 31. Moreover, since the screw rod 34 of the second transmission means 30 is threadedly connected on the nut 332 of the telescopic tube assembly 33, and the distal end of the screw rod 34 is fixedly connected on the third sliding unit 7, the rotation of the nut 332 can simultaneously drive the distal end of the screw rod 34 and the third sliding unit 7 to protrude. On the contrary, with the reverse rotation of the motor 11, the second sliding unit 6 and the third sliding unit 7 can be driven to retract relative to the first sliding unit 5.
With reference to FIGS. 6 and 7, the second embodiment of the present invention is shown. In addition to the aspect shown in the above embodiment, the driving means 10 of the present invention can has the motor 11 fixedly connected to one side of the base body 12 and the transmission shaft 111 penetrating into the base body 12 so as to drive the screw rod 21 of the first transmission means 20 to rotate. The screw rod 21 also drives the first gear 22 fixedly connected to its one end to rotate. Further, the first gear 22 and the second gear 32 of the second transmission means 30 engage with each other. A protruding shaft 321 extends outwardly from the bottom of the second gear 32. The protruding shaft 321 is fixed on the base body 12 of the driving means 10 via the lower bearing 36, so that the first gear 22 can simultaneously drive the sleeve 31 of the second transmission means 30 to rotate. As a result, the lifting device can be partially changed according to the requirements of various products so as to increase its field of application.
With reference to FIG. 8, it shows the third embodiment of the present invention. In addition to the aspect of the above embodiment, the transmission between the first transmission means 20 and the second transmission means 30 of the present invention can be achieved by the driving of a belt 25 between the first gear 21 of the first transmission means 20 and the second gear 32 of the second transmission means 30, thereby to reduce the unfavorable noise.
With reference to FIG. 9, it shows the fourth embodiment of the present invention. The driving means 10 of the present invention can be arranged to be vertical to the first transmission means 20 and the second transmission means 30. In addition, it can be arranged to be parallel to the first transmission means 20 and the second transmission means 30. Since the transmission shaft 111 of the motor 11 indirectly drives the first gear 22 of the first transmission means 20 via an idle wheel, and the first gear 22 directly engages with the second gear 32 of the second transmission means 30, the same effect of transmission can be achieved as that in previous embodiments. Further, the transverse width of the lifting device can be greatly reduced.
According to the above, the lifting device having parallel double screw rods of the present invention indeed has industrial applicability, novelty and inventive steps. Further, since the construction of the present invention has not been used in any products of the same kind or in public or published prior to applying for patent. Therefore, the present invention completely conforms to the requirements for a utility model patent.
Although the present invention has been described with reference to the foregoing preferred embodiments, it will be understood that the invention is not limited to the details thereof. Various equivalent variations and modifications can still be occurred to those skilled in this art in view of the teachings of the present invention. Thus, all such variations and equivalent modifications are also embraced within the scope of the invention as defined in the appended claims.
Patent Application
20070295126
