Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
  • A62B35/04—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion incorporating energy absorbing means
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62B—DEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
  • A62B35/00—Safety belts or body harnesses; Similar equipment for limiting displacement of the human body, especially in case of sudden changes of motion
  • A62B35/0043—Lifelines, lanyards, and anchors therefore
  • A62B35/0062—Rail-form lifelines for permanent installation

Definitions

• the present invention discloses a novel fall arrester with torsional energy absorbing means. Therefore, the technical filed of the invention belongs to the life-saving devices, more particular to fall arresters capable of sliding along a guide rail with energy absorbing means .
• Fall arresters are known to be movable along a guide rail of a climbing protection system and to have one or more rotatable mounted pawls which, in the event of a fall, engage against catching stops or slots in the guide rail. By engaging the catching stops or slots, the fall arrester is stopped in the guide rail to arrest a user from falling further.
• a connecting element of the fall arrester transmits the force to pawls from the user which is secured to the connecting element by a lanyard or other suitable attaching device.
• the present invention solves that issue by incorporating the : energy absorbing means into the structural parts of the arrester in the way that the absence or damage of the absorbing means, i.e. torsion stick, does not alter the functional properties of the fall arrester.
• whiplash injuries can arise from the fact that falling body is abruptly stopped from falling and the body inertia produces injuries under rapid deceleration.
• the idea behind the energy absorbing means is to minimise the stopping force, i.e. force used for material deformation or the force used to stretch the material. Available kinetic energy of the falling body has to be converted in the work that is the path integral of scalar product of the stopping force vector and the differential of the said path vector; which is absorbed by the energy absorbing means.
• the natural way to control the stopping force is to increase the path on which the work is done. Also, it is important that the stopping force is as constant as possible in time - that is hard to achieve by deformations that include twisting or tearing of the material used for the energy absorbing means .
• the second technical problem solved with the present invention is the construction of the energy absorbing means, in the form of torsion stick.
• torsion stick is capable to absorb the stopping energy in the uniform manner and to elongate the stopping force path of the torsion lever to which the falling body acts.
• the energy absorbing means may have a coil-form portion and an elongate tongue portion extending in a linear direction at the periphery of the coil- form portion.
• the disclosed invention uses torsion stick as the energy absorbing means which offers highly linear response to the torsion force; similar to those with springs.
• the disclosed invention works equally reliable no matter to which direction the external force is applied.
• the invention discloses a fall arrester with torsional energy absorbing means which is capable of sliding along a guide rail.
• Mentioned fall arrester is composed of left and right housings which are permanently connected together. Said connection is achieved by spring shaft, connecting shaft and load shaft. Connecting shaft and load shaft are equipped with the rollers on its ends. Two pairs of additional rollers are fixed by their corresponding axles to the housings. Parallel profile of the said guide rail is sandwiched by the mentioned rollers.
• Said load shaft is passing through load shaft bores on the left pawl and the right pawl allowing circular motion of the said pawls around the load shaft in the plane parallel to the housings.
• Other ends of said pawls are equipped with the cavities which form a part of the torsional energy absorbing means.
• Said pawls are pressed towards the parallel profile via spring spanned between the spring shaft and the spring pin that connects pawls, and by which force pawl tips engage simultaneously a pair of slots formed on said parallel profile.
• Torsional energy absorbing means consists of a torsion lever with a carabiner that engages the fall arrester, a torsion stick - to which the torsion is exerted; and a cylinder that stiffens the energy absorbing means.
• the torsion stick is fixed by one end to the left pawl and its opposite end is fixed within the cylinder. Cylinder partially enters left pawl cavity and nests fully into right pawl cavity where it can rotate freely.
• the cylinder is equipped with the polygonal portion on which torsion lever is mounted with its polygonal hole. The torsion lever is sandwiched between the pawls, and its relative motion, with respect to the pawls, rotates cylinder.
• Rotation of the cylinder within the pawl cavities exerts the force onto the torsion stick end fixed within the said cylinder.
• the cylinder starts to rotate relative to the torsion stick end which is fixed to the left pawl and torsion stick begins to absorb the energy of the falling body.
• the torsion stick left end oriented towards the left pawl is formed as the polygonal head with cross-section identical to the cross section bore made on the outer wall of the left pawl.
• Left torsion stick end is fixed to the left pawl by the fixation pin that enters cavity wall through firs fixation pin bore, passes the fixation pin bore formed on said left stick end, and comes out of the cavity through another fixation pin bore.
• the torsion right stick end oriented to the right pawl is formed as the polygonal head with cross-section identical to the cross section of the cylinder bore, made in the cylinder. Said cylinder is nested into the right pawl cavity.
• the maximum torsion angle by which torsion stick ends can relatively rotate when engaged by the torsion laver action is less than 180°.
• the spring shaft, connecting shaft and load shaft are fixed via screws to the housings, where said screws are inserted into the bores made on said housings.
• the additional axles carrying rollers are fixed to the housings by riveting said axles ends within the housing's bores. Each roller of the said fall arrester rotates independently.
• the carabiner is fixed to the torsion lever via hole situated on the opposite side of the polygonal hole for engaging the cylinder.
• Fig. 1 shows the fall arrester from its right side
• Fig. 2 shows the fall arrester from the bottom side which is turned to the guide rail
• Fig. 3 shows the fall arrester from its right side already positioned on the guide rail
• Fig. 4 shows the fall arrester from the bottom side with the guide rail sandwiched between the rollers.
• Fig. 5 shows fall arrester where left pawl is removed and inner parts can be easily seen.
• Fig. 6 shows the fall arrester where left pawl is removed and in position where fall arrester is mounted on the guide rail.
• Fig. 7 shows exploded view of the fall arrester with all parts visible.
• Fig. 8 shows the way torsion lever engages the cylinder.
• Fig. 9 shows the fall arrester stretched after being in operation, mounted on the guide rail.
• the present invention discloses a novel fall arrester with torsional energy absorbing means.
• the preferred embodiment is descripted below.
• the fall arrester with improved energy absorbing means consists of left housing (10) and right housing (20), Figs. 1 and 2.
• Housings (10) is shaped as a mirror image of housing (20) .
• Each housing is formed as elongated U-letter shaped metal piece with two rows of borings.
• First row of bores (11, 12) formed on the left housing (10) are designed to receive axles (31) for carrying a pair of rear rollers (30) .
• first row borings (21, 22) formed on the right housing (20) are designed also to receive axles (31) for carrying another pair of rear rollers (30) .
• Said axles (31) are riveted with its ends to the said housings (10, 20) in a manner that rollers (31) can freely rotate.
• the axles can be also fixed by screws or any other technique that is reliable and which enables rollers (31) to rotate freely and secure fall arrester to the rail guide ( 90 ) .
• Second rows of bores (13, 14, 15; 23, 24, 25) made on respective housings (10; 20) are designed to receive screws needed for fixation of said housings (10, 20) one to another.
• Three shafts are used for said purpose; connecting shaft (36) , spring shaft (33) and load shaft (38) .
• Connecting shaft (36) is fixed by screwing the ends of said shaft via screws inserted into bores (13, 23) .
• first rigid connection between the housings (10, 20) is established.
• the spring shaft (33) is fixed by screwing the ends of said shaft via screws inserted into bores (15, 25) made on housings (10, 20) by which the second rigid connection between the housings (10, 20) is established.
• the third connection is achieved by the load shaft (38) that is fixed by screwing the ends of said shaft via screws inserted into bores (14, 24) made on housings (10, 20) .
• Those rigid connections between the housings (10, 20) are visible on Figs. 2, 6 and 7 and form the frame of disclosed fall arrester.
• Connecting shaft (36) and the load shaft (38) have on its ends dedicated parts that form axles for the rollers (35, 37) respectively.
• Said rollers (35, 37) can freely rotate around said shafts (36, 38) and are nested within the housings (10, 20) as depicted on Figs. 2 and 6.
• Typical T-shaped guide rail (90) is depicted on Figs. 3 and 4; it consists of two profiles, parallel profile (91) and perpendicular profile (92) that are joined together.
• Parallel profile (91) is equipped with the slots (93), in our case said slots (93) are paired and distributed along the rail (90) in equal distances.
• Perpendicular profile (92) is equipped with auxiliary bores (94) distributed along the said profile (92), and do not interact with the fall arrester.
• rollers (30) Two pairs of previously mentioned rollers (30) are positioned on the parallel profile's (91) side which is oriented toward the side where perpendicular profile (92) is joined to it. Pair of rollers (37) and pair of rollers (35) are situated on the opposite side of the mentioned parallel profile (91) .
• the rollers (30, 35, 37) are sandwiching the parallel profile (91) of the said guide rail (90) together with the housings (10, 20) and are allowing the fall arrester to be guided along it "up” and “down", Figs. 3, 6 and 9; in the manner that is well known in the art.
• Fall arrester's insertion direction in the guide rail (90) is very important for normal operation.
• the fall arrester has mark “up” and the arrow indicating the insertion direction on the right housing (20), but this is not sufficient in practice. According to the safety standards, much safer solution has to be implemented. So, the pin (27) is inserted into bore (26) , Fig. 1, formed on the housing (20) . It allows the mentioned fall arrester to be inserted on the guide rail (90) in only one direction. If the fall arrester is inserted oppositely, the pin (27) prevents further sliding of the fall arrester across the guide rail (90) .
• the disclosed type of fall arresters have one or more rotatable mounted pawls which, in the event of a fall, engage against catching stops or slots in the guide rail (90) .
• a pair of pawls (40, 50) are used as depicted on Figs. 2, 4 and 6.
• Left pawl (40) geometry is best visible on Figs. 3 and 7. On one end it is mounted on the load shaft (38) that is passing through the load shaft bore (41) . For better mechanical properties, it is possible to insert flanged plain bearing (98) between the load shaft (38) and the shaft bore (41) , as visible on Fig. 5 for the pawl (50) .
• Another end of the left pawl (40) is formed as the cylinder with cavity (42) inside the cylinder.
• the cylinder base which encloses cavity (42), and which is oriented oppositely from the torsion lever (60), see Fig. 6, has a bore for receiving torsion stick end (71) .
• Left pawl (40) is equipped with two fixation pin bores (46) situated on the cylinder. Central part of the left pawl (40) has a tip (43) . Left pawl tip (43) is the part which actually engages slots (93) distributed along the parallel profile (91) of the guide rail (90), Fig. 6.
• the right pawl (50) geometry is best visible on the Fig. 5.
• the right pawl (50) is mirror image of the left pawl (40); having right pawl tip (53) , load shaft bore (51) and a cavity (52) formed within the cylinder situated on the opposite side form the load shaft bore (51) .
• the difference between left pawl (40) and right pawl (50) is that the cylinder base of the right pawl (50) , which is oriented oppositely from the torsion lever (60), is hollow - as visible on the Fig. 1.
• pawl tips (43, 53) simultaneously engage the slots (93) as depicted on the Fig. 4.
• the left pawl (40) and the right pawl (50) are connected via the spring pin (55) that is inserted through pin bores (44, 54) formed on said pawls (40, 50) .
• Spring (32) is stretched between the spring pin (55) and spring shaft (33) as depicted on Fig. 5. The force produced by the spring (32) presses pawls (40, 50), and their corresponding tips (43, 53) towards the parallel profile (91); Fig. 4. Once the pawl tips (43, 53) are positioned above the slots (93) they enter the slots and engage parallel profile (91) by which the fall arrester is secured on the guide rail (90).
• Pawl tips (43, 53), see Fig. 5, are designed to allow forward, i.e. UP movement of the arrester while the movement DOWN is possible only if the operator overcomes the spring (32) force. This system is well described in the related art and it will not be discusses further here.
• Energy absorbing means consists of: a lever (60) with a carabiner (99) that engages the fall arrester, a torsion stick (70) to which the torsion is exerted and the cylinder (80) which stiffens the energy absorbing means.
• the pawl cylinders and their corresponding cavities (42, 52) are also a part of the torsional energy absorbing means.
• the central element is torsion stick (70) , which is made of metal with carefully chosen mechanical properties.
• the torsion stick (70) has two ends, left end (71) is equipped with the fixation pin bore (73) . Both ends (71, 72) , according to the preferred embodiment, have polygonal shaped cross section.
• the torsion stick left end (71) cross section is dimensioned to be compatible with the pawl (40) cylinder base which encloses cavity (42), Figs. 5 and 6.
• the torsion stick end (71) nests into the said pawl (40) cylinder base and is locked there. However, for assembly purpose and real use, this position of the torsion stick end (71) has to be secured further.
• This torsion stick left end (71) is locked within the pawl cavity (42) via fixation pin (45).
• Fixation pin (45) is inserted through the first bore (46), formed on the cylinder part of the pawl (40), and is passing through the fixation pin bore (73) formed on said torsion stick left end (71) , and again comes out through second bore (46) .
• torsion stick left end (71) can be inserted and removed from its nest made in the pawl (40) cylinder, Figs. 5 and 6.
• Cylinder (80) is equipped with the bore (82) having cross section geometry that is capable to receive cross section geometry of the torsion stick end (72) .
• Cylinder (80) diameter is dimensioned to enter into both cavities (42, 52) made in pawls (40, 50) cylinders, and to form a sliding bearing with it.
• Part of the cylinder (80) that has to be inserted into the cavity (42) - Fig. 7 and 5, is shortened due to the space consumed by the fixation pin (45) .
• Part of the cylinder (80) is equipped with the polygonal portion (83) which serves to actuate the cylinder (80) by the torsion lever (60) , see Fig. 8.
• Torsion lever (60) has on one end carabiner hole (61) to which the carabiner (99) is mounted, and on the opposite side said lever (60) is equipped with the polygonal hole (63) .
• This polygonal hole (63) has dimensions that are compatible with the polygonal portion (83) formed on the cylinder (80).
• the torsion lever (60) is therefore sandwiched between the pawls (40, 50) as depicted on Figs. 5 and 6, and mounted on the cylinder (80).
• cylinder (80) starts to rotate around its main axis, see Fig 8. Then the part of the cylinder (80) situated within the right pawl cavity (52), Figs.
• the cylinder (80), to which the torsion lever (60) is mounted stiffens the energy absorbing means. It is done by the outer cylinder (80) diameter which allows to cylinder (80) to be almost perfectly nested into the pawls cavities (42, 52) .
• the industrial applicability of the disclosed fall arrester with torsional energy absorbing means is obvious.
• the disclosed fall arrester is functional safety device, especially suitable to be used whenever is possible to have sliding guides.

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• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Vibration Dampers (AREA)

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• 2016
  • 2016-01-15 EP EP16704047.6A patent/EP3402577A1/de not_active Withdrawn
  • 2016-01-15 WO PCT/HR2016/000001 patent/WO2017122035A1/en active Application Filing

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