The present invention is related to a buffer device, and more particularly to an axial buffer device and a fall protection device.
Working in elevated environments like roofs, factories, construction sites, aerospace bases, or in the situations like elevator repairing or shipbuilding, workers are usually required to wear safety equipment like fall protection device when they are working. The fall protection device is adapted to be connected with a safety belt, and the safety belt is fastened to the worker. When the worker falls from an elevated site accidentally, the fall protection device can stop or buffer the safety belt to prevent the worker continue to fall or slow down the falling speed of the worker to secure the safety of the worker.
Conventional fall protection devices may include an elastic stretch design for the safety belt, with this design as the worker attached with the safety belt falls, this stretchable safety belt can buffer or slow down the falling speed of the worker. However, the length, the elastic modulus, the height of the work site, also the weight of the worker, all of them must be considered when designing the safety belt. In the case that the length of the safety belt is too long, once the worker falls without the rebounding of the safety belt and hits the ground, injuries may occur.
There is another fall protection device having a portion of the safety belt with an overlay-sewing design. With this design on the safety belt, when the worker attached with the safety belt falls, the overlay-sewing portion of the safety belt would be ripped by the downward force, absorb the downward impulsive force of the worker, thereby providing the cushion effect. However, this design may damage the structure of the safety belt, affect its strength, and lower the load-bearing capacity, which may result in a dangerous situation.
Besides, there is also a fall protection device with a rapid lock-up design. As the worker falls, the pulling force will make the fall protection device lock up the safety belt immediately so as to prevent the worker from continuing to drop. However, this design may cause an instant impact force (like G-Force) and a counter force which may cause organ injuries or bone fractures to the worker.
In view of the above, an object of the present invention is to provide an axial buffer device and a fall protection device having the axial buffer device. By utilizing the design of the axial buffer device, it is favorable to buffer a falling speed or shorten a falling distance of an object which the axial buffer device is applied to. For example, when the axial buffer device is applied to the fall protection device, it is favorable to buffer a falling speed or shorten a falling distance of a worker or an object which is attached to the fall protection device. In addition, the axial buffer device could be applied to other objects, such as a pull ring, a hoist ring, a hook, a cord, etc. to provide a good buffer mechanism.
The present invention provides an axial buffer device, including a buffer rod having a first friction surface; and a buffer member having a second friction surface which contacts the first friction surface; when any one of the buffer rod and the buffer member is pulled by a force which is greater than a default value to overcome a maximum friction between the buffer member and the buffer rod, the buffer member would slide on the buffer rod with friction.
In one embodiment, the axial buffer device further includes a first spring, wherein the first spring is connected to the buffer rod to provide an elastic force to the buffer rod.
In one embodiment, the first spring is fit around the buffer rod; one of two ends of the first spring is connected to the buffer rod, and another one of the two ends of the first spring is connected to the buffer member.
In one embodiment, the axial buffer device further includes a second spring, wherein the second spring is fit around the buffer rod and interposed between the first spring and the buffer rod; one of two ends of the second spring is adapted to connect to the buffer rod, and another one of the two ends of the second spring is adapted to connect to the buffer member.
In one embodiment, an outer peripheral surface of the buffer rod forms the first friction surface; a through hole is disposed on the buffer member and includes an inner peripheral surface which forms the second friction surface; a fitting relation between the second friction surface and the first friction surface is an interference fit.
In one embodiment, the buffer member comprises a holder and a first buffer ring; the first buffer ring and the buffer rod are disposed within the holder; the first buffer ring is fit around the buffer rod and includes the second friction surface.
In one embodiment, the axial buffer device further includes a first spring, wherein the first spring is fit around the buffer rod; one of two ends of the first spring is connected to the buffer rod, and another one of the two ends is connected to the first buffer ring.
In one embodiment, the axial buffer device further includes a second spring, wherein the second spring is fit around the buffer rod and interposed between the first spring and the buffer rod; one of two ends of the second spring is connected to the buffer rod, and another one of the two ends of the second spring is connected to the first buffer ring.
In one embodiment, the buffer member further includes a second buffer ring; the second buffer ring is fit around the buffer rod and includes a third friction surface which faces the first friction surface of the buffer rod; the axial buffer device further comprises a first spring and a second spring; the first spring is fit around the buffer rod and disposed between the first buffer ring and the second buffer ring; two ends of the first spring respectively connect to the first buffer ring and the second buffer ring; the second spring is fit around the buffer rod; two ends of the second spring respectively connect to the second buffer ring and the buffer rod.
In one embodiment, the axial buffer device further includes another buffer rod, wherein the two buffer rods are disposed coaxially; the buffer member includes a holder, a first buffer ring, and a second buffer ring; the two buffer rods, the first buffer ring and the second buffer ring are disposed within the holder; the first buffer is fit around the buffer rod and includes the second friction surface; the second buffer ring is fit around the other buffer rod and includes a third friction surface which contacts a fourth friction surface on the other buffer rod.
In one embodiment, the axial buffer device further includes at least one spring, wherein the at least one spring is fit around one of the two buffer rods.
The present invention also provides a fall protection device adapted to connect to a safety belt. The fall protection device includes a frame, a rotation member disposed in the frame and adapted to roll up the safety belt, and the aforementioned axial buffer device, wherein one of the buffer rod and the buffer member is adapted to connect to a hanging point, and the other one is adapted to connect to the frame.
In one embodiment, the fall protection device further includes a brake unit and a housing, wherein the brake unit is disposed on the rotation member to restrict a rotation of the rotation member; the housing includes a first half housing and a second half housing which are opposite and joined to each other; a first division plate is disposed in the first half housing and a second division plate is disposed in the second half housing which is opposite to the first division plate; the rotation member is disposed in one part of the housing which is at one side of the first division plate and the second division plate, and the brake unit is disposed in another part of the housing which is at another side of the first division plate and the second division plate.
In one embodiment, the rotation member includes a shaft lever and a rotary drum; the brake unit is mounted on the shaft lever; the rotary drum is fit around the shaft lever to be rotated with the shaft lever coaxially.
In one embodiment, a fitting relation between the rotary drum and the shaft lever is an interference fit.
The advantage of the present invention is that: by utilizing the friction surfaces of the buffer rod and the buffer member of the axial buffer device which face to each other, the sliding friction generated between the buffer rod and the buffer member could cushion a force (or an impulsive force) when the force applied to the buffer rod or the buffer member is greater than a default value, whereby to buffer and absorb a falling force of the worker, and slow down a falling speed of the worker, which could avoid an injury to the worker. In addition, the probability of rebounding which makes a secondary damage to the worker also could be decreased.
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
The following illustrative embodiments and drawings are provided to illustrate the disclosure of the present invention, these and other advantages and effects can be clearly understood by persons skilled in the art after reading the disclosure of this specification. As illustrated in
The buffer rod 2 includes a first friction surface 2a. In the current embodiment, an outer peripheral surface of the buffer rod 2 forms the first friction surface 2a. In addition, the buffer rod 2 further includes a flange 2b, wherein the flange 2b is disposed at one end of the buffer rod 2 and protruded from the outer peripheral surface of the buffer rod 2.
The buffer member includes a second friction surface facing to the first friction surface 2a. In the current embodiment, the buffer member includes a first buffer ring 4. The buffer ring 4 includes a through hole, and an inner peripheral surface of the through hole forms the second friction surface 4a, wherein the first buffer ring 4 is adapted to be fit around the buffer rod 2 and contacts with the first friction surface 2a. Preferably, the fitting relation between the first buffer ring 4 and the buffer rod 2 is an interference fit (or a tight fit). In addition, in other applications, the fitting relation also could be a transition fit or a clearance fit, etc. Whereby, when a force applied to the buffer rod 2 or the first buffer ring 4, such as a component of an external force which is parallel to the axial direction of the buffer rod 2, is greater than a default value, the first buffer ring 4 would slide with friction on the buffer rod 2 by the force against to the maximum friction force between the first buffer ring 4 and the buffer rod 2 so as to buffer, absorb or offset the force.
Moreover, the axial buffer device 10 can further include a first spring 6. The first spring 6 is adapted to be connected to the buffer rod 2 to provide an elastic force for increasing the buffering effect of the buffer rod 2. In the current embodiment, the first spring 4 is fit around the buffer rod 2, wherein one of the two ends of the first spring 4 is adapted to be connected to the flange 2b of the buffer rod 2, and another of the two ends of the first spring 4 is adapted to be connected to first buffer ring 4. In more details, in the current embodiment, the first spring 4 is a compressed spring as an example, wherein two ends of the compressed spring abut against the flange 2b of the buffer rod 2 and the surface of the first buffer ring 4 respectively. Whereby, when the first buffer ring 4 slides with friction on the buffer rod 2 to be close to the flange 2b, the first spring 6 would be compressed to form an elastic force which could be used to buffer the force.
Referring to
The rotation member 30 includes a shaft lever 32 and a rotary drum 34. The shaft lever 32 penetrates through the through hole 24a, and the rotary drum 34 is mounted on the shaft lever 32 to be rotated with the shaft lever 32 coaxially. The rotary drum is adapted to roll up a safety belt 36, wherein one end of the safety belt 36 is adapted to be connected to a worker or a hanging point of a safety equipment wearing by the worker. In one embodiment, a fitting relation between the rotary drum 34 and the shaft lever 32 includes an interference fit (or a tight fit), such as a transition fit or a clearance fit, whereby a rotational friction would be generated between the rotary drum 34 and the shaft lever 32 due to the tight fit design of the rotary drum 34 and the shaft lever 32 when the shaft lever 32 stops rotating, which enables a slowing down of the falling speed of the safety belt 36 while being stretched out and deceleration of the falling speed of the worker worn with the safety belt 32. However, in other applications, the fitting relation of the shaft lever 32 and the rotary drum 34 is not limited to the above embodiment.
In the current embodiment, the axial buffer device includes a structure of the axial buffer device of the aforementioned embodiment. Therefore, the detailed description thereof is omitted here. The buffer member of the axial buffer device 10 further includes a holder 8. The holder 8 is disposed on the frame 20. In the current embodiment, a plurality of positioning holes are provided at a bottom of the holder 8, wherein the plurality of positioning holes could be penetrated with a plurality of bolts to fasten the holder 8 on the frame 20. However, in other applications, other fastening methods also could be utilized.
One of the buffer rod 2 and the buffer member is adapted to be connected to a hanging point, and the other is connected to the frame 20. In the current embodiment, the buffer rod 2 is disposed on the frame 20, and one end of the buffer rod 2 penetrates through a through hole 8a of the holder 8 to be connected to a hanging point. A hanging ring 40 is connected to one end of the buffer rod 2, and is adapted to hang on or fix to a hanging point. Alternatively, the hanging ring 40 also could be utilized together with a cord to connect to the hanging point. Wherein, the hanging point includes, for example, a steel reinforcing bar, a pillar, a steel cord or a cable rope which enables the buffer rod 34 to indirectly or directly connect to the hanging point, but it is not limited thereto. In addition, the hanging point is not limited to a fixed point or an anchoring point. For example, the hanging point could be a hanging member which is connected to a cord which could slide along a longitudinal direction of the cord. In another embodiment, the buffer rod 2 could be connected to the frame directly or indirectly and the holder 8 could be connected to the hanging point directly or indirectly. It is not limited thereto.
Furthermore, in the current embodiment, the fall protection device 100 further includes a brake unit 50, a rewinding unit 60 and a housing 70.
The brake unit 50 is disposed on the rotation member 30. As shown in
The rewinding unit 60 includes a first cover 62, a second cover 64 and a spiral spring 66. Wherein, the first cover 62 is combined with the second cover 64 to form a containing space for receiving the spiral spring 66 which coils up normally One end of the spiral spring 66 is connected to the shaft lever 32, and another is connected to the second cover 64.
The housing 70 is adapted to receive the axial buffer device 10, the frame 20, the rotation member 30, the brake unit and the rewinding unit 60. The housing 70 includes a first half housing 72 and a second half housing 74 which are joined to each other, wherein a first division plate 73 is provided in the first half housing 72, and a second division plate 75 is provided in the second half housing 74; the first division plate 73 and the second division plate 75 are opposite to each other. The first half housing 72 and the second half housing 74 could be combined together by positioning members such as bolts S, whereby the first division plate 73 and the second division plate 75 could be joined to each other to divide the containing space of the housing 70 into two parts. One part of the containing space which is located at one side of the first division plate 73 and the second division plate 75 is adapted to receive the frame 20 and the rotation member 30, and another part of the containing space which is located at the other side of the first division plate 73 and the second division plate 75 is adapted to receive the brake unit 50. With the design of the first division plate 73 and the second division plate 75, the rotation member 30 could be isolated from the brake unit 50 and thereby to prevent small objects such as dust particles carried by the safety belt 36 which is wound around the rotation member 30 being entered or adhered to the brake unit 50 and decrease the interference to the operation of the brake unit 50. Besides, the spiral spring 66 is received in the first cover 62 and the second cover 64, which is capable of avoiding the intrusion of the small objects such as dust particles as well. Moreover, the axial buffer device 10 is isolated with the top plate 22, which is also favorable to avoid the intrusion or adhesion of small objects such as dust particles carried by the rotation member 30 and the safety belt 36. In addition, in one embodiment, the axial buffer device 10 is not limited to be enclosed by the housing 70, and could be exposed on an exterior of the housing 70.
With the above-mentioned design, in a normal situation, for example, as a worker walks normally on a working platform or a pallet, the rotation unit 30, the brake unit 50, and the rewinding unit 60 rotates coaxially (or synchronous rotary). When the safety belt 36 bears a pulling force smaller than a default value, for example, the worker attached with the safety belt 36 is away from the fall protection device 100 and the safety belt 36 is being pulled, the spiral spring 66 of the rewinding unit 60 stretches and stores a restoring force (or elastic force) for coiling because of the pulling from the safety belt 36. On the contrary, when the worker approaches the fall protection device 100, the force to pull the safety belt 36 would decrease to a value lower than the elastic force of spiral spring 66 such that the elastic recovery appears and the spiral spring 66 coils back so as to drive the safety belt 36 to wind around the rotary drum 34 again.
In another situation that the safety belt 26 is being pulled rapidly at a moment, such as a worker attached with the safety belt 26 falls from an elevated site accidentally, the safety belt 26 would be pulled out rapidly by a pulling force which is greater than the default value, whereby the braking parts 54 of the brake unit 50 would be spun out by overcoming the elastic force of the restoring spring 56. Then, the braking parts 54 would engage with a stopper 25 disposed on the frame 20, which fixes the braking plate 52, as well as the shaft lever 32 which is connected to the braking plate 52. Referring to
As shown in
Furthermore, the first spring 6 is not limited to the compressed spring. In one embodiment, the first spring 6 could be a tension spring to be connected between the frame 20 and the buffer rod 2, which provides an elastic force for restoring the buffer rod 2 to its initial position. In addition, in other applications, other types of springs also could be utilized. In one embodiment, two ends of the tension spring could be connected to the holder 8 and the first buffer ring 4 respectively to provide a restoring elastic force to cushion the falling force.
As illustrated in
As illustrated in
It is worth mentioning that a default value whether the pulling force applied to the safety belt is greater enough is used as a reference to determine whether a buffering effect of the axial buffer device is initiated or not. In practice, the default value could be different values according to a degree of the interference fit and a contacting area between the buffer rod and the buffer member, an elastic coefficient of the spring, or the arrangement of the fall protection device for different applications. For example, the default value is mainly determined by the friction between the buffer rod and the buffer member. However, when the axial buffer device further includes a spring, the default value would be further adjusted by an elastic force provided by the spring. In addition, in one embodiment, the brake unit or the rewinding unit could be omitted. For example, when the safety belt wound on the rotation member is being pulled out until the rotation member stops rotating, such as a full length or nearly a full length of the safety belt is pulled out, the force applies to the rotation member through the safety belt would be greater than a default value, and the buffer member of the axial buffer device would be pulled to slide on the buffer rod with friction, which could cushion the falling force.
As illustrated in
As illustrated in
As illustrated in
Referring to
Referring to
It shall be understood that two ends of each of the springs, the first spring or the second spring of each of the above embodiments are not necessary to abut against the flange of the buffer rod or the buffer member at an initial state but are spaced apart with a predetermined distance when the axial buffer device is not initiated or does not cushion. Until the buffer member slides on the buffer rod with friction, the two ends of the spring would be connected or abut against the buffer rod and the buffer member to provide an elastic force to the cushioning process.
It is worth mentioning that the aforementioned axial buffer device is not limited to the axial buffer device of the first embodiment, and could be any one of the axial buffer devices of the second to the fourth embodiments.
It must be pointed out that the embodiments described above are only some embodiments of the present invention. The fall protection device is not only adapted to attach to a worker to provide a protection when the worker accidentally falls, but also could be adapted to hang on an object such as working material or a machine tool, which could also avoid a rapid falling of the working material or the machine tool. All equivalent structures which employ the concepts disclosed in this specification and the appended claims should fall within the scope of the present invention.
Number | Date | Country | Kind |
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106118118 | Jun 2017 | TW | national |