Connecting device for connecting a fan blade to a rotor of a motor of a ceiling fan

[0001] 1. Field of the Invention

[0002] This invention relates to a connecting device for a ceiling fan, more particularly to a connecting device for connecting a fan blade to a rotor of a motor of a ceiling fan.

[0003] 2. Description of the Related Art

[0004] Referring to FIG. 1, a conventional ceiling fan 10 is shown to comprise a motor casing 16 for housing a motor 12 which includes a stator 122 and a rotor 121 that is concentrically surrounded by the stator 122 and that is rotatable about an axial direction. A plurality of fan blades 13 are connected to the rotor 121 by mounting arms, 11 respectively. Each mounting arm 11 has two plate-like connecting ends 111,113 which are mounted respectively and securely on the rotor 121 and the corresponding fan blade 13 by means of screw fasteners 14,15. It is inconvenient to assemble the fan blades 13 due to the use of the screw fasteners 14, 15.

[0005] To facilitate assembly of the ceiling fan, referring to FIGS. 2 and 3, another mounting arm 21 for the conventional ceiling fan is shown to have three coupling members 23 at one connecting end 212. Three mounting holes 25 are formed in the fan blade 24. Each mounting hole 25 has a notch portion 251 and a bore portion of a dimension larger than that of the notch portion 251 such that each coupling member 23 can be brought to fit snugly in the notch portion 251 of the respective mounting hole 25 by passing through the bore portion. A spring plate 22 is secured on the mounting arm 21 and has an engaging spring tongue 221 at one end thereof for abutting against the fan blade 24.

[0006] However, the assembly of the mounting arm 21 on the rotor (not shown) is still inconvenient to conduct. In addition the mounting arm 21 involves increased packaging and transport costs.

[0007] The object of the present invention is to provide a connecting device which is easy to fabricate and which can permit substantial reductions in the packaging and transport costs thereof.

[0008] According to this invention, a connecting device includes a bottom member with a periphery for attaching on a rotor of a motor, a circumferential wall which extends upwardly from the periphery, and an anchoring end for anchoring on the bottom member such that the mounting arm is oriented in a radial direction relative to the bottom member. A tightening member is disposed between the anchoring end and the bottom member to tighten the anchoring end relative to the bottom member through a clamping force generated in a circumferential direction of the bottom member when the anchoring end is pulled away from the bottom member in the radial direction. A guiding member is disposed between the anchoring end and the bottom member to guide the anchoring end to move in the radial direction relative to the bottom member. A retaining member is disposed between the tightening member and the anchored end in the radial direction, and has an engaging spring member abutting against the circumferential wall once the anchoring end is moved away from the bottom member.

[0019] Before the present invention is described in greater detail, it should be noted that same reference numerals have been used to denote like elements throughout the specifications.

[0020] Referring to FIGS. 4 and 5, a first preferred embodiment of a connecting device according to the present invention is shown to be adapted to connect a fan blade 50 to a rotor 301 of a motor 30. The rotor 301 has a bottom member 30a which is disposed transverse to the axial direction, and which has two screw holes 31 formed therein adjacent to a periphery thereof. A circumferential wall extends upwardly from the perpher of the bottom member 30a and diverges upwardly so as to form an annular slanting wall 30b. An elongate mounting block 32 is mounted on the bottom member 30a, and has two through holes 322 such that two screw fasteners 33 respectively pass through the through holes 322 to engage threadedly the screw holes 31 so as to secure the mounting block 32 on the bottom member 30a. Two elongate grooves 321 are formed in the mounting block 32 at opposite ends thereof, and extend in the radial direction to pass through from an inner side distal to the periphery of he bottom member 30a to an outer side of the mounting block 32.

[0021] A mounting arm 40 includes a plate-like anchored end 43 which is adapted to be secured on an upper surface wall of the fan blade 50, and an anchoring end 41 opposite to the anchored end 43 in the radial direction. The anchoring end 41 has two elongate rails 411, each of which extends in the radial direction to correspond with a respective one of the elongate grooves 321 so as to fit slidably in the respective elongate groove 321. Since each of the elongate grooves 321 and the elongate rails 411 extends in the radial direction, that is, a distance between the elongate grooves 321 is increased gradually from the inner side of the mounting block 32 to the outer side, a clamping force is generated to tighten each elongate rail 411 in the corresponding elongate groove 321 when the anchoring end 41 of the mounting arm 40 is pulled outwardly from the inner side of the mounting block 32 to the outer side. Thus, the anchoring end 41 can anchor tightly on the mounting block 32 to prevent further outward movement of the anchoring end 41 relative to the mounting block 32.

[0022] A retaining member 42 includes a spring plate 421 which is mounted on the mounting arm 40 at one end, and which has an engaging spring member or tongue 422 at the other end that extends toward the anchoring end 41. Thus, once the elongate rails 411 of the anchoring end 41 are moved in the elongate grooves 321 from the inner side toward the outer side, the engaging spring tongue 422 abuts against the annular slanting wall 30b and provides an upward biasing force thereto, thereby preventing movement of the anchoring end 41 inwardly relative to the mounting block 32.

[0023] Alternatively, referring to FIG. 6, instead of the retaining member 42, a biasing member 37 has an inner end which is secured to the bottom member 30a, an outer end which extends outwardly and downwardly and which has an engaging spring tongue 371 with a biasing force so as to abut against the anchoring end 41, and a middle portion 372 between the inner and outer ends. The bottom member 30a further has a concavity 36 which can receive the middle portion 372 when the biasing member 37 is bent against: the biasing force thereof so as to be steered away from the anchoring end 41, thereby preventing the biasing member 37 from hindering the assembly of the anchoring end 41 to the mounting block 32.

[0024] As illustrated, the anchored end 43 of the mounting arm 40 and the mounting block 32 can be mounted respectively on the fan blade 5O and the bottom member 30a by operators in a manufacturing plant. There is no need to increase the size of the package, thereby reducing substantially the packaging and transport costs.

[0025] Subsequently, when it is desired to assemble the fan blade 50 on the bottom member 30a, the elongate rails 411 of the anchoring end 41 are moved in the elongate grooves 321 from the inner side toward he outer side in the radial direction. Then, the engaging spring tongue 422 (or 371) of the retaining member 42 (or the biasing member 37) abuts against the slanting wall 30b (or the anchoring end 30b) so as to retain firmly the anchoring end 41 to the mounting arm 32.

[0026] Referring to FIGS. 7 and 8, the second preferred embodiment of the connecting device according to this invention is shown to include a guiding member with two L-shaped elongate rails 34 which are disposed on the bottom member 30a adjacent to the periphery of the bottom member 30a to confine two elongate grooves respectively, and two inverted L-shaped elongate rails 44 which are disposed on the anchoring end 41 of the mounting arm 40 and which correspond to the elongate rails 34 to, engage slidably the elongate grooves respectively.

[0027] A tightening member includes a mounting hole 45 which is formed in the anchoring end 41 between the the elongate rails 44, and an elastomeric coupling member 35 which is mounted securely on the bottom member 30a between the elongate rails 34 by a screw fastener 353. The mounting hole 45 is confined by an inner peripheral wall which has a constricted portion 453 to divide the mounting hole 45 into a notch portion 452 and a bore portion 451 that is distal to the bottom member 30a and that has a dimension larger than that of the notch portion 452. The coupling member 35 includes a shank 351 which has an upper end for mounting on the bottom member 30a and a lower end that extends downward from the upper end, and a peripheral flange 352 which projects radially and outwardly from the lower end of the shank 351 and which has a dimension larger than that of the notch portion 452 and smaller than that of the bore portion 451. Thus, the coupling member 35 can fit snugly in the notch portion 452 by passing the shank 351 thereinto after the peripheral flange 352 has been brought to pass through the bore portion 451.

[0028] In assembly, similar to the first preferred embodiment, the elongate rails 44 of the anchoring end 41 are fitted in the elongate grooves of the bottom member 30a outwardly to the periphery of the bottom member 30a. At the same time, the shank 351 of the coupling member 35 is moved to be fitted snugly in the notch portion 452, thereby retaining the anchoring end 41 to the bottom member 30a and avoiding further outward movement of the anchoring end 41 relative to the bottom member 30a by virtue of the inner peripheral wall of the notch portion 452. In addition, with reference to FIGS. 8 and 9, a retaining member 42 and a biasing member 37 are disposed similar to those of the first preferred embodiment shown in FIGS. 5 and 6. While the present invention has been described in connection with what is considered the most practical and preferred embodiments, it is understood that this invention is not limited to the disclosed embodiments but is intended to cover various arrangements included within the spirit and scope of the broadest interpretations and equivalent arrangements.