Patent Application
20080000735
This invention will be better understood by referring to the accompanying drawings, wherein:
A preferred embodiment of a braking device for a power winch in the preset invention, as shown in
The reduction box 1 secured on the power winch has its interior installed with a reduction gear set and its outer side bored with an accommodating hollow 11 having its inner side formed with a frictional surface. The reduction box further has its center bored with an insert hole for a motor spindle to pass therethrough, as shown in
The fixing base 2 is fixed in the accommodating hollow 11 of the reduction box 1 by bolts and positioned around the circumference of the insert hole 12 of the accommodating hollow 11 but not contacting with the inner edge 111 of the accommodating hollow 11. Further, the fixing base 2 has its slanting circumferential edge formed with a frictional surface 21.
The braking lining 3 to be assembled in the accommodating hollow 11 of the reduction box 1 is composed of at least two blocks 31 able to be integrated to form a ring-shaped braking lining 3. Each block 31 has the opposite sides of its inner edge respectively formed with a slope 32, and one of the two slopes 32 abuts the frictional surface 21 of the fixing base 2; therefore, the gradients of the slope 32 of the block 31 and the frictional surface 21 of the fixing base 2 are preferably the same. In this preferred embodiment, the braking lining 3 is composed of three blocks 31, as shown in
The sectional shaft 4 fitted on the motor spindle S (but unable to drive each other) is inserted in the insert hole 12 of the reduction box 1 and has the annular wall of its opposite ends formed with teeth 41. The teeth 41 on the annular wall of one end that is inserted in the insert hole 12 of the reduction box 1 are engaged with the reduction gear set in the reduction box 1 for rotating together.
The elastic member 5 is a volute spring fitted on the sectional shaft 4, having one end inserted and positioned in the hole 42 of the sectional shaft.
The first engraved block 6 is fitted on the sectional shaft 4 but unable to drive each other. The elastic member 5 has the other end inserted and positioned in the first engraved block 6. The first engraved block 6 is provided with an annular base 61 protruding outward on one side reverse to the elastic member 5. The annular base 61 is formed with plural corrugated slopes 611 and has its opposite outer walls respectively disposed with an actuating projection 612. The first engraved block 6 further has its outer circumferential edge formed with a slanting frictional surface 62 whose gradient is preferably the same as that of the inner circumferential edge 21 of the braking lining 2.
The second engraved block 7 is formed with a central hole having its inner wall provided with teeth 71 to be engaged with the teeth 41 on the annular wall of outer end of the sectional shaft 4 to enable the sectional shaft 4 and the second engraved block 7 to be rotated together. The second engraved block 7 is firmly positioned on the sectional shaft 4 by a set of C-shaped clasps 7A to prevent the second engraved block 7 from shifting. The second engraved block 7 is further provided with a slope 711 and two actuating projections 712 respectively corresponding with the slope 611 and the actuating projections 612 of the first engraved block 6, only there is slight angle error between the slopes 611, 711 and between the actuating projections 612, 712, such structure being the same as that of foresaid U.S. Pat. No. 6,520,486.
The clutch base 8 has its outer side bored with a central engage hole 81 to be engaged and combined with the outer end of the motor spindle S to enable the whole clutch base 8 to be driven to rotate by the motor spindle S. The engage hole 81 of the clutch base 8 has its outer circumferential edge formed with a bush base 82 for fitting a shaft bush 8A thereon. The clutch base 8 further has its inner side disposed with a set of symmetrical projecting blocks 83, as shown in
The reduction box rear cover 9 is fixed on the reduction box 1 and fitted with the shaft bush 8A of the clutch base 8 so that the shaft bush 8A can firmly hold the outer side of the clutch base 8 to let the clutch base 8 rotated with great steadiness.
After being assembled, the braking lining composed of two or more blocks 32 is positioned between the inner edge of the accommodating hollow 11 and the frictional surface 21 of the fixing base 2 as well as the frictional surface 62 of the first engraved block 6, and the frictional surface 21 and 62 are respectively adjacent to one slope 32 of the braking lining 3 and contact with the slope 32 with a same gradient. Before carrying out braking, the braking lining is under a floating state due to allowance of size and separation of the first engraved block 6 from the braking lining 3, in other words, there is a gap formed between the inner edge of the accommodating hollow 11 and the fixing base 2 as well as the first engraved block 6.
To sling up the heavy load, simply press a ascending button to let the motor spindle S and the clutch base 8 rotate together, and simultaneously one projecting block 83 of the clutch base 8 will push the actuating projection 612, 712 of the first and the second engraved block 6, 7 to actuate the first and the second engraved block 6, 7 to rotate synchronously. At this time, the sectional shaft 4 will be actuated to rotate together with the second engraved block 7 to drive the reduction gear set to rotate and drive the rope drum of the power winch to turn and retract the steel rope for slinging up the heavy load. To lower down the heavy loads (or only to release the steel rope), only press a descending button to let the motor spindle S rotate reversely for releasing the steel rope and lowering down the heavy loads.
During slinging up or lowering down heavy loads, the motor can be stopped operating by pressing a stopping key, and the motor will automatically stop operating when power outage happens. When the motor stops operating, the motor spindle S and the clutch base 8 will stop rotating immediately and the projecting blocks 83 of the clutch base 8 will also stop pushing the first and the second engraved block 6, 7. At the instant, the reverse torsional force produced by the heavy loads hung on the steel rope will force the second engraved block 7 to push the first engraved block 6 to move (this action being the same as that described in the U.S. Pat. No. 6,520,486) to let the frictional surface 62 on the outer circumferential edge of the first engraved block 6 push against the slope 32 of each block 31 of the braking lining 3 and produce friction and braking action between them. Simultaneously, the blocks 31 of the braking lining 3 will be forced to move and contact with the frictional surface 21 of the fixing base 2 and the inner edge 111 of the accommodating hollow 11 to produce friction and braking action, that is, the braking lining 3 can instantly contact with the inner edge 111 of the accommodating hollow 11, the frictional surface 21 of the fixing base 2 and the frictional surface 62 of the first engraved block 6. Under such great friction and braking action, the first and the second engraved block 6, 7, the clutch base 8, the sectional shaft 4, the motor spindle S and the rope drum as well as the heavy load hung on the steel rope will stop movement immediately, letting the whole power winch completely stop functioning.
As can be noted from the above description, this invention has advantages described as follows.
1. The braking lining 3 is an independent component and it is under a floating state before carrying out braking; therefore, when the motor is started to operate, even if the first and the second engraved block 6, 7 are rotated, the braking lining 3 will not be actuated to rotate so it will be free from wear.
2. Only when the motor stops operating, will the braking lining 3 contact with the frictional surface 62 of the first engraved block 6 and the frictional surface 21 of the fixing base 2 as well as with the inner edge 111 of the accommodating hollow 11 and begin to function, able to prevent wear and prolong service life and having excellent effect on braking.
3. In case the braking lining 3 should be damaged, only the braking lining 3 has to be replaced without involving other components, conforming to economic gain.
4. The braking lining 3 can be replaced with a new one easily and conveniently, having great practicability.
While the preferred embodiment of the invention has been described above, it will be recognized and understood that various modifications may be made therein and the appended claim are intended to cover all such modifications that may fall within the spirit and scope of the invention.
