Patent Application
20220161071
The present invention relates generally to a fall arrester, and more particularly to a fall arrester with dustproof effect.
When working in high-altitude places, the operator must be equipped with fall arresters. An end of a fall arrester is connected to a support, and the cable or lifeline in the fall arrester is fastened to the operator. In this way, if the operator accidentally falls from a height, the sudden falling force will drive a braking device in the fall arrester to avoid the cable or lifeline from continuing to be pulled out by the falling force, or to reduce the speed at which the cable or lifeline is pulled out, so that the safety of operator would be maintained.
A conventional fall arrester usually includes a case to prevent external dust or impurities from entering the inside of the fall arrester, wherein the case has an opening for the cable or lifeline to enter and exit the case. However, during the cable or lifeline is being wound back to the case, the external dust or impurities could be easily brought into the case. Such dust or impurities would accumulate in the braking device easily, which affects the effect of the driven braking device and even causes the braking device to get stuck so that the fall arrester could lose its emergency lock function. Thus, the conventional fall arrester is unable to ensure the safety of work. From the above, the conventional fall arrester has to be improved.
In view of the above, the primary objective of the present invention is to provide a fall arrester which can prevent dust from accumulating in the braking device and the at least one pawl of the fall arrester, which could affect the operation of the fall arrester.
The present invention provides a fall arrester including a holder, a rotating drum, a braking device, and a dust cover. The holder includes a first arm and a second arm. The rotating drum is pivotally provided on the holder and located between the first arm and the second arm; the rotating drum includes a main body and at least one pawl, wherein the main body has an accommodating part and a setting part; the accommodating part is provided to be wound by a flexible long strip; the at least one pawl has a first abutting portion and is pivotally provided on the setting part; when the rotating drum rotates at a speed which is equal to or more than a predetermined speed, the first abutting portion of the at least one pawl pivots form a first position to a second position. The braking device has a convex portion and is fixed to the first arm by the convex portion so that the braking device is located between the first arm and the setting part; the braking device further has a second abutting portion which is located on a rotation path of the first abutting portion in the second position, wherein the rotation path is formed by the rotation of the rotating drum; thus, the second abutting portion can abut against the first abutting portion to stop the rotation of the rotating drum. The dust cover is fixed to the setting part and is located between the setting part and the first arm; an enclosed space is formed between the dust cover and the setting part, and the at least one pawl and the braking device are located in the enclosed space; the dust cover has a hole, and the convex portion protrudes from the hole.
The effect of the present invention is that, the dust cover covers the braking device and the at least one pawl so that the braking device and the at least one pawl are located in the enclosed space formed between the dust cover and the setting part, which prevents dust or impurities from accumulating in the braking device and the at least one pawl, which affects the operation of the fall arrester.
The present invention will be best understood by referring to the following detailed description of some illustrative embodiments in conjunction with the accompanying drawings, in which
As shown in
As depicted in
The rotating drum 20 is located in the accommodation space S. A pivot hinge 19 passes through the canter of the rotating drum 20, and two ends of the pivot hinge 19 are fixedly connected to the first arm 12 and the second arm 14, respectively. In this way, the rotating drum 20 is pivotally connected to the holder 10 by the pivot hinge 19, and can therefore rotate relative to the holder 10 within the accommodation space S. The rotating drum 20 includes a main body 22 and two pawls 24, wherein the main body 22 has an accommodating part 222 and a setting part 224.
The accommodating part 222 can be divided into a reduced diameter part 222a and an enlarged diameter part 222b in an axial direction thereof, wherein the reduced diameter part 222a is caved along a radial direction of the main body 22, and the enlarged diameter part 222b expands along the radial direction of the main body 22. A side edge in an axial direction of the reduced diameter part 222a of the accommodating part 222 is connected to the enlarged diameter part 222b of the accommodating part 222. Additionally, the reduced diameter part 222a and the enlarged diameter part 222b in this embodiment are integral, but this is not a limitation of the present invention. Another side edge in the axial direction of the reduced diameter part 222a of the accommodating part 222 is detachably connected to the setting part 224. However, in other practical applications, the accommodating part 222 and the setting part 224 could also be integral. In the first embodiment, a cable 50 is wound around an outer periphery of the reduced diameter part 222a of the accommodating part 222, and is limited to be located between the enlarged diameter part 222b of the accommodating part 222 and the setting part 224. Furthermore, a free end of the cable 50 passes through the through hole 200b and is exposed to the outside of the case 200 for being pulled to drive the rotating drum 20 to rotate. The accommodating part 222 is not limited to be wound by the cable 50, and can be wound by other flexible long strips such as rope or lifeline.
The two pawls 24 of the rotating drum 20 are pivotally installed on an outer wall 224a of the setting part 224, and are located at two opposite sides of the outer wall 224a respectively. Each of the pawls 24 has a first abutting portion 242 which is located at a tip of each pawl 24. In addition, an end portion that is opposite to the first abutting portion 242 of each pawl 24 is connected to a retractable spring 25. An end of each retractable spring 25 is connected to the pawl 24, and the other end is fixed to the outer wall 224a of the setting part 224. In the first embodiment, the retractable spring 25 fits around a stud which is fixed to the outer wall 224a so as to be fixed to the outer wall 224a. The retractable spring 25 is provided for keep each pawl 24 in a first position P1; in other words, without any external force, the pawl 24 can be maintained in a normally open state without touching the braking device 30. As shown in
The braking device 30 fits around the pivot hinge 19, and is located between the first arm 12 and the setting part 224. The braking device 30 includes a ratchet wheel 32, a center shaft plate 34, and a cover plate 36. The ratchet wheel 32 has a plurality of ratchet teeth 322 on a periphery thereof. A tip of each of the ratchet teeth 322 constitutes a second abutting portion 322a. The distance between each second abutting portion 322a and the center of the pivot hinge 19 is fixed and greater than the distance between the first abutting portion 242 in the second position P2 and the center of the pivot hinge 19. That is, each second abutting portion 322a is located on a rotation path of the first abutting portion 242 in the second position P2, formed by the rotation of the rotating drum 20. The cover plate 36 has a penetration hole 36a. The center shaft plate 34 has a convex portion 342 which protrudes outward form a surface center of the center shaft plate 34 along a center axis thereof, wherein the convex portion 342 inserts into the penetration hole 36a and is fixed to the first arm 12. A part of the center shaft plate 34 is located between the ratchet wheel 32 and the cover plate 36, and the cover plate 36 is fixed to the ratchet wheel 32, so that two plate surfaces of the center shaft plate 34 are in frictional contact with the ratchet wheel 32 and the cover plate 36 respectively so as to form a frictional decelerating device. Therefore, the ratchet wheel 32 and the cover plate 36 can be frictionally rotated relative to the fixed center shaft plate 34.
The dust cover 40 includes a main cover 42 and two auxiliary covers 44, wherein the main cover 42 has a hole 42a in a center thereof; the two auxiliary covers 44 are connected to a periphery of the main cover 42, and located on two opposite sides. The dust cover 40 is fixed to the outer wall 224a of the setting part 224, and is located between the setting part 224 and the first arm 12. Furthermore, the abovementioned convex portion 342 protrudes from the hole 42a and is fixed to the first arm 12. An enclosed space A is formed between the dust cover 40 and the setting part 224, and the braking device 30 is located in the main cover 42. The two pawls 24 are located in the two auxiliary covers 44 respectively. In addition, the contour of the hole 42a of the dust cover 40 is corresponding to the shape of the convex portion 342, which prevents a gap formed between the hole 42a and the convex portion 342 from being too large, making dust enter the enclosed space A from the gap, or alternatively prevents the tight fit between the hole 42a and the convex portion 342, which hinders the dust cover 40 from rotating relative to the convex portion 342.
By such design, as shown in
In the first embodiment, the number of the pawls 24 is two, but this is not a limitation of the present invention. Using one pawl, even more than three pawls, cooperating to the braking device, can also achieve the purpose of stopping the rotation of the rotating drum. For example, in another embodiment, the number of the pawls is three, and the distance between each pawl and the pivot hinge are the same, and the distance between any two adjacent pawls are the same as well. By such design, the bonding strength between the pawls and the ratchet wheel can be strengthened. Additionally, in said another embodiment, the number of the auxiliary covers of the dust cover is also increased to three, and each auxiliary cover covers one of the pawls to achieve the purpose of dust prevention. From the above, there is a positive correlation between the number of the pawls and the number of the auxiliary covers. Moreover, the purpose of the design that uses the main cover with auxiliary covers rather than a whole piece of dust cover is to save the material cost of producing the dust cover.
From the above, the dust cover 40 covers the braking device 30 and the pawls 24 to prevent external dust from affecting the fall arrest function of the fall arrester, and thus to maintain the product safety.
It must be noted that the embodiments described above are only preferred embodiments of the present invention. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.
