OVERLOAD PROTECTION MECHANISM FOR WINCH

An overload protection mechanism for a winch that includes an input transmission shaft, an output transmission shaft, and a clutch mechanism. The input transmission shaft has a first transmission end, the output transmission shaft has a second transmission end. The clutch mechanism has a first clutch member disposed on the first transmission end and a second clutch member disposed on the second transmission end such that the first and second clutch members are correspondingly rotatable with the input transmission shaft and the output transmission shaft. The first and second clutch members are detachably engageable with each other. When the output transmission shaft is overloaded, the first and second clutch members are disengaged for preventing the overloaded power transmission between input transmission shaft and output transmission shaft.

TECHNICAL FIELD

The present invention is related to a winch, and particularly to an overload protection mechanism for the winch.

BACKGROUND OF THE INVENTION

A winch is a mechanical device that uses the rotation of the spool to wind or release ropes, such as, steel ropes. After the winding of the cable is completed, if the power source continues to output power to the transmission shaft installed in the spool, the transmission shaft is likely to be damaged. In order to avoid this situation, an overload protection mechanism is usually set inside the winch to protect the transmission shaft, so that the transmission shaft can release the power transmission with the power source when the load is too large.

The prior art teaches that the overload protection mechanism, as disclosed in the Republic of China (Taiwan) Patent No. 1622549, mainly relies on the combination of the rolling element and the inner and outer arc grooves to release the power transmission between the input transmission shaft and the transmission ring in the case of excessive load, so that the input transmission shaft cannot transmit power to the output transmission shaft in order to protect the overall structure. This structure, however, can still be improved.

SUMMARY OF THE INVENTION

One of the purposes of the present invention is to provide an overload protection mechanism for a winch, which has a good overload protection.

In order to achieve such benefit, the overload protection mechanism of the present invention includes an input transmission shaft, an output transmission shaft, and a clutch mechanism. The input transmission shaft and the output transmission shaft coaxially correspond to each other, the input transmission shaft has an input end and a first transmission end, and the output transmission shaft has a second transmission end and an output end. The clutch mechanism has a first clutch member, a second clutch member and an elastic part. The first clutch member is set at the first transmission end of the input transmission shaft, so that the first clutch member can operate synchronously with the input transmission shaft. The second clutch member is set at the second transmission end of the output transmission shaft, so that the second clutch member can operate synchronously with the output transmission shaft. In addition, the first clutch member has a first engaged part, and the second clutch member has a second engaged part. The first engaged part of the first clutch member is detachably engaged in the second engaged part of the second clutch member, and the elastic part acts on the first clutch member to push the first clutch member in the direction of the second clutch member.

In view of such structure, under the condition that the output end of the output transmission shaft is under normal load, the first engaged part of the first clutch member and the second engaged part of the second clutch member are engaged with each other, so that the input transmission shaft can transmit power to the output transmission shaft through the clutch mechanism, and the output transmission shaft can rotate smoothly. Once the output end of the output transmission shaft is overloaded, the first engaged part of the first clutch member and the second engaged part of the second clutch member will be disengaged which cuts off the power transmission between the input transmission shaft and the output transmission shaft, so that the input transmission shaft cannot transmit power to the output transmission shaft, thereby protecting the overall structure.

Preferably, the first engaged part of the first clutch member is one of recesses or bumps. At least one of the first engaged parts is a bump that has two first inclined planes which are inclined in opposite directions and one first plane which connects the two first inclined planes. The second engaged part of the second clutch member is the other one of the recesses or bumps that matches the corresponding recess or bump of the first engaged part. For example, the second engaged part can include a recess that has two second inclined planes which are inclined in opposite directions and one second plane which connects the two second inclined planes. Therefore, when the first engaged part of the first clutch member is engaged with the second engaged part of the second clutch member, the first inclined plane of the first engaged part abuts on the second inclined plane of the second engaged part, and the first plane of the first engaged part abuts on the second plane of the second engaged part. When the output end of the output transmission shaft is overloaded, with the cooperation of the first inclined plane and the second inclined plane, the first engaged part of the first clutch member engaged with the second engaged part of the second clutch member can be quickly and surely disengaged.

Preferably, the outer surface of the first transmission end of the input transmission shaft has an insertion portion. The first clutch member has the first shaft hole. The first clutch member is sleeved on the first transmission end of the input transmission shaft with the first shaft hole. In addition, the wall of the first shaft hole has an insertion slot. The input transmission shaft is engaged in the insertion slot of the first clutch member with the insertion portion of the first transmission end, so that the input transmission shaft is able to drive the first clutch member to rotate them together.

Preferably, the first transmission end of the input transmission shaft has a screw hole and the clutch mechanism also has a screw. The screw passes through a washer and is screwed in the screw hole, so that the washer abuts against the first transmission end of the first clutch member and the input transmission shaft to prevent the first clutch member from falling off.

Preferably, the one side of the first clutch member opposite to the second clutch member has a shaft and a container surrounding the shaft. The elastic part is sleeved, e.g., is set on, the input transmission shaft. The outer circumferential surface of the input transmission shaft has a shoulder between the input end and the first transmission shaft. The clutch mechanism also has a support ring. One side of the support ring abuts the shoulder of the input transmission shaft. The other opposite side of the support ring receives one end of the elastic part. The other end of the elastic part is sleeved on the shaft of the first clutch member and located in the container of the first clutch member, and abuts on the one side of the first clutch member facing the second clutch member, so that the elastic part is able to provide elastic force, e.g., spring force, to push the first clutch member toward the second clutch member.

Preferably, the second clutch member has a second shaft hole. The second clutch member is sleeved on the second transmission end of the output transmission shaft with the second shaft hole. The wall of the second shaft hole has a second section intersection. The outer circumferential surface of the second transmission end of the output transmission shaft has a first section intersection, so that the first and the second section intersections are able to abut each other, so that the second clutch member can rotate with the output transmission shaft.

Preferably, the second transmission end of the output transmission shaft has a locking ring slot and a locking ring is provided in the locking ring slot. The locking ring abuts against one side of the second clutch member facing the first clutch member to prevent the second clutch member from falling off.

Preferably, the shape of the input end of the input transmission shaft is hexagonal in order to connect with the chuck so that the input transmission shaft can be driven to be rotated by the electric tool with the aforementioned chuck.

The detailed structure, features, assembly or use of the overload protection mechanism for the winch provided by the present invention will be described in the detailed description of the following embodiments. However, those with ordinary knowledge in the field of the present invention should be able to understand that the detailed description and the specific embodiments listed in the implementation of the present invention are only for describing the present invention, and do not limit the scope of claims of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the specification, including the following embodiments and claims, nouns involving directionality are based on the direction as shown in the figures. In the following embodiments and drawings, the same element numbers represent the same or similar elements or structural features.

As shown inFIG. 1, the winch10contains an enclosure12, a spool14and a reduction-gear set16. The spool14is set in the enclosure in a rotatable manner. The reduction-gear set16is set in the enclosure12and connected to one end of the spool14, so that the spool14can be driven by the reduction-gear set16to wind or release the rope, e.g., steel cable or rope (not shown in the figure).

As seen inFIG. 2andFIG. 3, the overload protection mechanism18of the present invention includes an input transmission shaft20, an output transmission shaft30, and a clutch mechanism40.

The input transmission shaft20is rotatably arranged on the spool14and has an input end21and a first transmission end22. The input end21is located outside the spool14, and the input end21has a shape that is able to connect with the chuck (not shown in the figure) of an electric tool, e.g., having a hexagonal shape, and is configured so that the input transmission shaft20is able to be driven by the electric tool, e.g., to rotate. The first transmission end22is located in the spool14. The outer circumferential surface of the first transmission end22has a plurality of elongated insertion portions23arranged in an equally spaced ring shape, and the first transmission end22has a screw hole24extending along its axial direction. In addition, the outer circumferential surface of the input transmission shaft20also has a shoulder25between the input end21and the first transmission end22.

The output transmission shaft30is rotatably arranged on the spool14and is located on the same axis as the input transmission shaft20. The output transmission shaft30has an output end31and a second transmission end32. The output end31is located outside the spool14and is connected to the reduction-gear set16(as shown inFIG. 4), so that the output transmission shaft30is able to drive the reduction-gear set16. The second transmission end32is located in the spool14and has a first section intersection33. The outer circumferential surface of the second transmission end32also has a locking ring slot34.

The clutch mechanism40has a first clutch member50, a second clutch member60and an elastic part68.

The first clutch member50has a first shaft hole51that penetrates the opposite sides of left and right sides of the first clutch member50. The wall of the first shaft hole51has a plurality of elongated insertion slots52arranged in an equally spaced ring shape. The first clutch member50uses the first shaft hole51to be sleeved on the first transmission end22of the input transmission shaft20, and then uses the insertion slots52to be embedded on the insertion portions23of the first transmission end22of the input transmission shaft20, so that the first clutch member50is driven by the input transmission shaft20so that they rotate together. In addition, a screw58passes through a washer59and is locked in the screw hole24of the first transmission end22of the input transmission shaft20, so that the washer59abuts against the right side of the first clutch member50and the end surface of the first transmission end22of the input transmission shaft20to prevent the first clutch member50from detaching from the first transmission end22of the input transmission shaft20.

The second clutch member60has a second shaft hole61that penetrates the two opposite sides of the left and right sides of the second clutch member60. The wall of the second shaft hole61has a second section intersection62. The second clutch member60uses the second shaft hole61to be sleeved on the second transmission end32of the output transmission shaft30, where its right side abuts against a thrust bearing66provided on the output transmission shaft30, and then uses the second section intersection62to abut the first section intersection33of the second transmission end32of the output transmission shaft30, so that the second clutch member60drives the output transmission shaft30so that they rotate together. In addition, a locking ring67is buckled into the locking ring slot34of the second transmission end32of the output transmission shaft30and abuts against the left side of the second clutch member60to prevent the second clutch member60from detaching from the second transmission end32of the output transmission shaft30. As shown inFIG. 3andFIG. 5, the edge of the left side of the second clutch member60has multiple second engaged parts63. The second engaged parts63are arranged in a ring shape at equal intervals around the second shaft hole61. Each second engaged part63is the other one of recesses or bumps. In this embodiment, at least one of the second engaged parts63is a bump that has two second inclined planes64with opposite inclination directions and one second plane65connecting the two second inclined planes64. Therefore, as shown inFIG. 5, when the first engaged part55of the first clutch member50is engaged with the second engaged part63of the second clutch member60, a first inclined plane56of the first engaged part55abuts the second inclined plane64of the second engaged part63, and the first plane57of the first engaged part55abuts the second plane65of the second engaged part63.

The elastic part68, e.g., a compression spring here, is sleeved on the input transmission shaft20. As shown inFIG. 3andFIG. 4, one end of the elastic part68is located in a container54of the first clutch member50, e.g., housing of the first clutch member50, and is sleeved on a shaft53of the first clutch member50, and abuts against the left side of the first clutch member50. The other end of elastic part68is pressed against a support ring69. The support ring69is sleeved on the input transmission shaft20and abuts against the shoulder25of the input transmission shaft20and is fixed therewith. In this way, the elastic part68can provide elastic force to push the first clutch member50toward the second clutch member60.

It can be seen from the above that when the input transmission shaft20is driven by the electric tool, the first clutch member50rotate together with the input transmission shaft20. As seen inFIG. 5, the first clutch member50uses the engaged relationship between its first engaged part55and the second engaged part63of the second clutch member60to drive the second clutch member60to rotate together. Then, the output transmission shaft30is driven by the second clutch member60to start the reduction-gear set16, so that the reduction-gear set16will further drive the spool14to rotate, so as to achieve the effect of winding the rope.

When the rope is wound up, the output transmission shaft30will stop rotating with the spool14along with the second clutch member60. If the electric tool continues to output power to the input transmission shaft20at this time, the input transmission shaft20will also drive the first clutch member50to rotate. However, if the first clutch member50starts to rotate, since the second clutch member60remains stationary, through the cooperation, e.g., engagement, of the first inclined plane56and the second inclined plane64, on the one hand, the first clutch member50moves along the axial direction of the input transmission shaft20away from the second clutch member60, which compresses the elastic part68to accumulate the elastic force of the elastic part68, e.g., recovery power. On the other hand, the first clutch member50also rotates relative to the second clutch member60, so that the first engaged part55of the first clutch member50gradually separates from the second engaged part63of the second clutch member60. While the two are completely separated, the power transmission between the input transmission shaft20and the output transmission shaft30is cut off.

In summary, in terms of the present invention's overload protection mechanism18for a winch10, under the condition that the output end31of the output transmission shaft30is under normal load, the first engaged part55of the first clutch member50and the second engaged part63of the second clutch member60are engaged with each other, so that the input transmission shaft20can transmit power to the output transmission shaft30through the clutch mechanism40, so that the output transmission shaft30can rotate smoothly. Once the output end31of the output transmission shaft30is overloaded, the first engaged part55of the first clutch member50and the second engaged part63of the second clutch member60will be disengaged to cut off the power transmission between the input transmission shaft20and the output transmission shaft30, so that the input transmission shaft20cannot transmit power to the output transmission shaft30, and the overall structure is protected.