Patent Application
20160311667
1. Field of the Invention
The present invention relates to a torque limiter for a power winch, and more particularly to the torque limiter applied to a power winch and capable of timely cutting off the power whenever the reverse torque produced by a carrying load exceeds the bearable torque of the power supply, so as to prevent the power winch from being damaged by overload.
2. Description of the Related Art
Power winch is a device designed for hanging or dragging a load. For example, a hoist is a common application of the power winch, and a cable winch installed at the front of a jeep or a cross-country vehicle for trailing another car (to help others) or moving out of danger (to rescue oneself) is another common application of the power winch. The principle of operating the power winch is to output a forward or reverse transmission power by a power supply (such as a power motor) and acted by a reduction mechanism to drive a cable wheel to rotate in a forward or reverse direction to release or retrieve a cable, and a load (such as a heavy object, another car, or another object) is hooked by a heavy-duty hook installed at a front end of the cable, so as to move the load conveniently.
Since the winch carries a load (such as goods, objects, or people waiting to be rescued), and the load sometimes exceeds the torque bearable by the power supply (which involves the loading capacity of the power supply), therefore a torque limit mechanism for preventing any torque produced by the load and unbearable by the power supply is generally installed in a transmission mechanism, such that if an overload occurs, the torque limit mechanism will rotate idly and slip and will no longer transmit power, so as to protect the transmission mechanism (such as a power motor, a reduction mechanism, etc) of the power winch, and prevent the components of the power winch from being damaged by the overload. However, the conventional power winch generally uses a conventional circuit breaker as the torque limit mechanism, such that when the torque of the load increases, the current of the power supply current also increases. Therefore, the power of the power supply will be disconnected when there is an overload of current, so as to provide the effect of limiting the torque indirectly. However, the circuit breaker cannot be turned off or on immediately when the circuit breaker is used as a torque limit mechanism, due to the time lapse. Therefore, the power of the power winch cannot be stopped immediately when there is an overload, but the output of power will continue for a short period of time before the power winch stops. Obviously, such application causes tremendous trouble to users and requires further improvements.
Therefore, it is a primary objective of the present invention to provide a torque limiter for a power winch, so that when a carrying load produces a reverse load exceeding the load bearable by the power supply, the power will be cut off immediately to prevent the power winch from being damaged by overload.
To achieve the aforementioned and other objectives, the present invention provides a torque limiter for a power winch, and the torque limiter comprises: a frame, a power supply installed on a side of the frame and capable of outputting power; a reduction gearbox installed on the other side of the frame and including a reduction mechanism installed therein, and a long shaft being driven to rotate by the power of the power supply to provide a reduction effect, and an end of the long shaft forming a latching end; a cable wheel installed at the middle of the frame and driven to rotate by the power outputted by the reduction gearbox; and a torque limit mechanism being installed in a process of transmitting power from the power supply to the reduction mechanism through the long shaft; characterized in that the torque limit mechanism is comprised of a torsion shaft, a friction plate, a brake pad, a disc-shaped elastic member, an adjustable positioning ring, and a positioning screw ring, wherein the torsion shaft includes an axial through slot formed therein, a latching slot formed at a front end of the torsion shaft, a threaded section formed on an outer periphery of the torsion shaft, and positioning cavity axially and deeply penetrated into the torsion shaft; the friction plate is a ring-shaped plate with friction surfaces; the brake pad is a ring-shaped plate made of a lining material and having a positioning protrusion formed at the inner periphery of the brake pad; the disc-shaped elastic member is substantially in a concave arc shape and has compressive elasticity; the outer periphery of the adjustable positioning ring includes a plurality of positioning plates and selectively bent in a direction towards the positioning screw ring; the positioning screw ring has a shaft hole with a reverse inner thread, and the outer periphery has a plurality of symmetrical positioning grooves formed thereon and provided for deviating, pressing, and remaining the selected positioning screw plate therein.
In the torque limiter for a power winch, the torque limit mechanism has an inner housing installed in front of the reduction mechanism in the reduction gear for entering power and coupled to the reduction mechanism, and a through hole formed at an end of the inner housing, and during assembling, the torsion shaft is passed through the friction plate and the through hole of the inner housing, so that the friction plate is attached to the torsion shaft, and the through slot of the torsion shaft is sheathed on the long shaft, and a latching end at an end of the long shaft is inserted into and closely coupled to the latching slot of the torsion shaft, and the brake pad is mounted onto the torsion shaft outside the inner housing, and the positioning protrusion is entered into the positioning cavity, and the disc-shaped elastic member, the adjustable positioning ring and the positioning screw ring are sheathed on the torsion shaft sequentially, and the shaft hole of the positioning screw ring is screwed and coupled to the threaded section, until the torsion shaft, the friction plate, the inner housing, the brake pad, the disc-shaped elastic member, the adjustable positioning ring and the positioning screw ring are packed tightly, and the positioning plate of the adjustable positioning ring is bent and pressed into the corresponsive positioning groove of the positioning screw ring to limit and prevent the positioning screw ring from being rotated or withdrawn.
In the torque limiter for a power winch, the torque limit mechanism is installed in the assembly of the reduction mechanism, and the reduction mechanism has a first planetary gear set comprising three identical small gears with a common center shaft inserted into a base and a cover and arranged into a triangular shape, and the base has a through hole formed at the center of the base, and a large accommodating slot formed on a surface of the base and facing the small gears and connected to plurality of small cavities formed on the inner periphery of the base; and the cover has a through hole corresponsive to the through hole of the base, and the outer periphery of the friction plate further includes a plurality of small flanges, such that during assembling, the torsion shaft is passed through the disc-shaped elastic member and the brake pad, and the positioning protrusion of the brake pad is entered into the positioning cavity of the torsion shaft, and then the torsion shaft is passed through the through hole of the base, so as to attach the brake pad onto the back side of the base, and the friction plate is contained into the large accommodating slot of the base in the manner of corresponding the small flanges one by one to the small cavities and provided for passing the torsion shaft, and then the adjustable positioning ring and the positioning screw ring are sheathed on the torsion shaft sequentially, so that the shaft hole of the positioning screw ring is screwed and engaged with the threaded section until the torsion shaft, the disc-shaped elastic member, the brake pad, the base, the friction plate, the adjustable positioning ring and the positioning screw ring are packed closely, and the positioning plate of the adjustable positioning ring is bent and pressed into the corresponsive positioning groove of the positioning screw ring to limit and prevent the positioning screw ring from being rotated and withdrawn.
In the torque limiter for a power winch, when the torque limit mechanism is installed at the power supply that outputs power, a sleeve is coupled to the center shaft of the power supply, and a large accommodating slot is formed at an end of sleeve away the shaft, and the outermost section of the inner periphery of the large accommodating slot has a plurality of small cavities, and the outer periphery of the friction plate has a plurality of small flanges, such that during assembling, the torsion shaft is passed through the friction plate, the brake pad, the disc-shaped elastic member, the adjustable positioning ring and the positioning screw ring sequentially, so that the friction plate is attached onto the torsion shaft, and the positioning protrusion of the brake pad is entered into the positioning cavity of the torsion shaft, and the shaft hole of the positioning screw ring is screwed and engaged with the threaded section of the torsion shaft until the torsion shaft, the friction plate, the brake pad, the disc-shaped elastic member, the adjustable positioning ring and the positioning screw ring are packed closely, and the positioning plate of the adjustable positioning ring is bent and pressed into the corresponsive positioning groove of the positioning screw ring to limit and prevent the positioning screw ring from being rotated and withdrawn, and then the torque limit mechanism is contained in the large accommodating slot of the sleeve, and the small flanges of the friction plate are inserted and positioned into the small cavities of the sleeve in one-to-one correspondence, and the latching end of the long shaft is inserted into the latching slot of the torsion shaft for a connection.
The technical characteristics, contents, advantages and effects of the present invention will be apparent with the detailed description of a preferred embodiment accompanied with related drawings as follows.
The present invention provides a torque limit mechanism installed during a transmission process of a power winch and provided for timely cutting off the power transmission whenever the torque produced by a carrying load exceeds a torque bearable by the power supply, so that the torque limit mechanism may be installed at any position in the power transmission process. For example, the torque limit mechanism is installed before the power is entered into the reduction gearbox (in other words, it is installed at the front of the reduction mechanism), or it is directly installed in the assembly of reduction mechanism, or it is installed when power is outputted by the power supply, and the preferred embodiments are described in details below.
In the first preferred embodiment, the torque limit mechanism is installed in front of the reduction mechanism in the reduction gearbox for entering the power (in other words, it is installed at the front of the reduction mechanism). With reference to
In
A wedge block 36 has an engaging gear 361 installed to an inner wall of a center hole of the wedge block 36 engaged and linked with the engaging gear 332 on the ring wall of the sectional shaft 33. In other words, a direct driving and rotating relation exists between the sectional shaft 33 and the wedge block 36, a set of C-shaped retainer ring 362 is latched into the engaging slot 334 for limiting the wedge block 36 from displacing beyond the sectional shaft 33, and the wedge block 36 has a bevel 363 and a convex latching body 364 corresponsive to the bevel 353 and the convex latching body 354 of the disc-shaped rim 35 respectively, but both of the convex latching bodies 354, 364 are installed with slightly different angles. An inner housing 37 facing an end of the wedge block 36 is an opening 371 (as shown in
A torque limit mechanism A is comprised of a torsion shaft 38, a friction plate 391, a brake pad 392, a disc-shaped elastic member 393, an adjustable positioning ring 394 and a positioning screw ring 395, wherein the torsion shaft 38 has an axial through slot 381 formed therein (as shown in
In
When the power supply 20 is turned on (regardless of outputting a forward power or a reverse power), the long shaft 21 is driven to rotate by the power supply 20, and the torque limit mechanism A and the inner housing 37 are synchronously rotated by the close connection between the latching end 211 and the latching slot 382, and then the bump 373 inside the inner housing 37 pushes the convex latching bodies 354, 364 to rotate synchronously. Since the engaging gear 361 of the wedge block 36 and the engaging gear 332 on the ring wall of the sectional shaft 33 are engaged and linked with each other, the sectional shaft 33 is driven to rotate, so as to provide a predetermined deceleration effect of the reduction mechanism 32 and drive the cable wheel 40 to rotate and release a cable (not shown in the figure) or retrieve the cable.
When the power supply 20 is turned off (through a manual control/operation or a power failure), the long shaft 21, the torque limit mechanism A and the inner housing 37 will be stopped immediately, and then the cable of the cable wheel 40 carrying a load will produce a reverse torque, and the linkage of the cable and the reduction mechanism 32 pushes the sectional shaft 33 and the wedge block 36 to produce a reverse rotation, so that the convex latching body 364 of the wedge block 36 is separated with respect to the bump 373 inside the inner housing 37, and the bevel 363 of the wedge block 36 momentarily press the bevel 353 of the disc-shaped rim 35, so that the disc-shaped rim 35 is moved quickly towards the inner circular shell 31, and the oblique friction surface 341 of the brake block 34 is attached quickly to the oblique friction surface 312 of the inner circular shell 31 to produce a braking effect for braking the brake block 34 and stopping the wedge block 36, the sectional shaft 33, the reduction mechanism 32 and the cable wheel 40 with the cable accordingly.
The power supply 20 regardless of being turned on or off will produce a reverse torque as long as the cable is loaded. When the reverse torque produces the brake effect and/or the power supply 20 is capable of bearing the torque, then there will be no problem for the application. However, if the reverse torque produces the brake effect and/or reaches a level almost not bearable by the power supply 20, then the reverse torque will force the wedge block 36 to push the inner housing 37 to rotate in a reverse direction. Now, the torsion shaft 38 is stopped together with the power supply 20, so that rotation of the inner housing 37 will force the friction plate 391 to rotate altogether, but the torsion shaft 38 and the brake pad 392 will be released from the compressed status with the inner housing 37 to remain still, so as to protect the power supply 20 from being damaged.
A power winch 1 in accordance with the second preferred embodiment of the present invention has the same structural look and effects as the embodiment as shown in
A torque limit mechanism B, is comprised of a torsion shaft 48, a friction plate 491, a brake pad 492, a disc-shaped elastic member 493, an adjustable positioning ring 494 and a positioning screw ring 495, wherein the torsion shaft 48 has an axial through slot 481 formed therein and provided for passing the through the long shaft 21 with spacing, and a small section of the outer periphery has a threaded section 483 with a reverse outer thread, and a positioning cavity 485 is formed at a selected position of the outer periphery and penetrated to the inside in an axial direction, and its rear end has an engaging gear 486. The friction plate 491 is a ring-shaped plate having a surface with a friction effect, and the outer periphery further includes a plurality of small flanges 4911, and the friction plate 491 and the small flanges 4911 have sizes precisely corresponsive to those of the large accommodating slot 412 and the small cavity 413 of the base 41. The brake pad 492 is a ring-shaped plate made of a lining material, and its inner periphery has a positioning protrusion 4921. The disc-shaped elastic member 493 is substantially in a concave arc shape and has a compressive elasticity. The outer periphery of the adjustable positioning ring 494 has a plurality of positioning plates 4941 which can be selectively bent towards the positioning screw ring 495. The positioning screw ring 495 has a shaft hole 4951 with a reverse inner thread, and a plurality of symmetrical positioning grooves 4952 formed at the outer periphery and provided for bending, pressing and remaining the selected positioning screw plate 4941.
In
After the power supply 20 is turned on (regardless of outputting a forward power or a reverse power), and the power is supplied to the sectional shaft 33, the three small gears of the first planetary gear set 321 are driven to rotate around the inner teeth 431 of the second inner circular shell 43, so that the whole first planetary gear set 321 is rotated. Now, the torque limit mechanism B and the base 41 are situated at a compressed status, so that the torque limit mechanism B is rotated synchronously with the first planetary gear set 321. When the power supply 20 is turned off (by manual control or operation, or by power failure), the first planetary gear set 321 and the torque limit mechanism B will be stopped immediately, and the reverse torque produced by the carrying load pushes the torque limit mechanism B and the first planetary gear set 321 to produce a reverse rotation through the linkage with the cable and another layer planetary gear set on the reduction mechanism 32. If the reverse torque is not bearable by the power supply 20, then the reverse torque will force the torsion shaft 48 to rotate in a reverse direction. Now, the sectional shaft 33 and the first planetary gear set 321 are stopped with the power supply 20, therefore the reverse rotation of the torsion shaft 48 will force the brake pad 492 to rotate altogether but the base 41 and the friction plate 491 will be separated from the compressed status with the brake pad 492 and will remain still, so as to protect the power supply 20 from being damaged.
A power winch 1 in accordance with the third preferred embodiment of the present invention has the same structural look and effects as the embodiment as shown in
With reference to
A torque limit mechanism C is comprised of a torsion shaft 58, a friction plate 591, a brake pad 592, a disc-shaped elastic member 593, an adjustable positioning ring 594 and a positioning screw ring 595, wherein the torsion shaft 58 contains a latching slot 581 substantially in a non-circular shape (such as a hexagonal shape) in the axial direction and provided for engaging an end of the non-circular (or hexagonal) latching end 212 corresponsive to the long shaft 21, and a small section of the outer periphery of the torsion shaft 58 has a threaded section 583 with a reverse outer thread, and a positioning cavity 585 formed at a selected position of the outer periphery and penetrated into the inside in an axial direction; the friction plate 591 is a ring-shaped plate having a surface with a friction effect, and the outer periphery further has a plurality of small flanges 5911, and the friction plate 591 and the small flanges 5911 have sizes precisely corresponsive to those of the large accommodating slot 232 and the small cavity 233 of the sleeve 23; the brake pad 592 is a ring-shaped plate made of a lining material, and has a positioning protrusion 5921 formed at the inner periphery; the disc-shaped elastic member 593 is substantially in a concave arc shape and has a compressive elasticity; the outer periphery of the adjustable positioning ring 594 has a plurality of positioning plates 5941 which can be selectively bent towards the positioning screw ring 595; the positioning screw ring 595 has a shaft hole 5951 with a reverse inner thread, and a plurality of symmetrical positioning grooves 5952 formed at the outer periphery for bending, pressing and remaining the selected positioning screw plate 5941.
In
When the power supply 20 is turned on (regardless of outputting a forward power or a reverse power), and the power is supplied from the center shaft 22 to the sleeve 23, the torque limit mechanism C is packed and the plurality of small flanges 5911 of the friction plate 591 are inserted and packed into the small cavities 233 of the sleeve 23 in a one-to-one correspondence, and the latching end 212 of the long shaft 21 is inserted into the latching slot 581 of the torsion shaft 58 to achieve a connection, and the torque limit mechanism C and the long shaft 21 are driven by the sleeve 23 to rotate synchronously. When the power supply 20 is turned off (by manual control or operation, or by power failure), the sleeve 23 and the long shaft 21 will be stopped immediately, but the reverse torque produced by a carrying load will push the long shaft 21 but the linkage of the cable and the reduction mechanism 32, so that the torque limit mechanism C and the sleeve 23 produce a reverse rotation. If the reverse torque is not bearable by the power supply 20, then the reverse torque will force the torsion shaft 58 to rotate in a reverse direction. Now, the sleeve 23 is stopped together with the power supply 20, so that the reverse rotation of the torsion shaft 58 will force the brake pad 592 to rotate accordingly, but the sleeve 23 and the friction plate 591 are released from the compressed status with the brake pad 592 and remain still, so as to protect the power supply 20 from being damaged.
In view of the aforementioned three preferred embodiments of the present invention, a torque limit mechanism is selectively installed in a power winch during a power transmission process for outputting power from the power supply 20 and transmitting the power through the long shaft 21 to the reduction mechanism 32, and the torque limit mechanism is installed before the power is supplied to the reduction mechanism inside the reduction gear (in order word, it is installed at the front end of the reduction mechanism), installed directly in the assembly of the reduction mechanism, or installed when the power supply outputs power, so that if the reverse torque produced by the carrying load of the power winch exceeds the reverse torque bearable by the power supply, the power transmission will be cut off immediately to assure that the use of the power supply 20 will not exceed the loading capacity, so as to prevent the power winch from being damaged.
| Number | Date | Country | Kind |
|---|---|---|---|
| 104206236 | Apr 2015 | TW | national |
| 201520260306.0 | Apr 2015 | CN | national |
