CA2152025A1 - Device and method for arresting a fall - Google Patents
Device and method for arresting a fallInfo
- Publication number
- CA2152025A1 CA2152025A1 CA 2152025 CA2152025A CA2152025A1 CA 2152025 A1 CA2152025 A1 CA 2152025A1 CA 2152025 CA2152025 CA 2152025 CA 2152025 A CA2152025 A CA 2152025A CA 2152025 A1 CA2152025 A1 CA 2152025A1
- Authority
- CA
- Canada
- Prior art keywords
- drum
- rotation
- fall arrester
- pawl
- ring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
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
- A62B35/0093—Fall arrest reel devices
Abstract
A device for arresting the fall of an individual wherein a plurality of layers of a elongated webbing are wound on a drum so that when a fall occurs the weight of the fall is absorbed by compaction of the layers of the elongated webbing on the drum and the elongation of the portion of the elongated webbing unreeled from the drum.
Also, a locking mechanism is disclosed when a spring urges a pawl against a rotating surface having a cam until the speed of rotation of the cam overcomes the force of the spring and moves the pawl into engagement with a catch. The cam moves the pawl into the engagement zone at lower than locking speeds and requires the normal action of the spring and pivot pin to pull the pawl out of the engagement zone before the tip of the sperrad engages it, thus providing a fail safe advantage. In further embodiments, the device is attached to a body safety harness usually worn by a worker.
Also, a locking mechanism is disclosed when a spring urges a pawl against a rotating surface having a cam until the speed of rotation of the cam overcomes the force of the spring and moves the pawl into engagement with a catch. The cam moves the pawl into the engagement zone at lower than locking speeds and requires the normal action of the spring and pivot pin to pull the pawl out of the engagement zone before the tip of the sperrad engages it, thus providing a fail safe advantage. In further embodiments, the device is attached to a body safety harness usually worn by a worker.
Description
` - - 21S2025 A DEVICE AND METHOD FOR ARRESTING A FALL
Field of the Invention This invention relates generally to devices for arresting the fall of an individual and more particularly to the use of webbing wound on the drum of a fall arresting device to arrest the fall.
Backqround of the Invention There are many devices in the marketplace for arresting the fall of an individual. These range from lanyards with no shock absorbing device to lanyards with shock absorbers that are made by the stitching of layers of a safety harness together so that a fall is arrested by the breakinq of the stitching to elaborate devices using retractable lanyards to limit free fall distance and clutches or other braking devices to slow down and stop the rotation of the lanyard drum. While all of these devices have proved to be effective in various degrees, there still exists a need for a relatively simple, inexpensive but effective device for arresting the fall of an individual.
Brief Description of the Invention This invention provides a device and a method for arresting the fall of an individual using an elongated webbing wound on a rotatable drum in a housing so that, when a fall occurs and the rotation of the drum is stopped, the fall arresting force is absorbed by the compaction of a plurality of layers of the elongated webbing and in some instances by the compaction of a resilient means between the drum and the first layer of the elongated webbing and when necessary, by the elongation of the portion of the elongated webbing located outside of the housing.
In a preferred embodiment of the invention, the fall arresting device comprises a housing having an opening formed therein. A drum is rotatably mounted in the housing and has an axis of rotation. An elongated webbing is wound on the drum and has one end secured to the drum and the other end thereof passing out through the opening. A connecting device is secured to the other end of the elongated webbing for connecting the other end where desired, such as to a harness on a worker. Force applying means, such as a falling body, apply a force on the connecting device to rotate the drum. Stop means are provided for preventing rotation of the drum when a predetermined rotational velocity thereof has been reached. Arresting means are provided for absorbing the fall arrest energy and reducing the deceleration forces applied to the load supporting device.
Field of the Invention This invention relates generally to devices for arresting the fall of an individual and more particularly to the use of webbing wound on the drum of a fall arresting device to arrest the fall.
Backqround of the Invention There are many devices in the marketplace for arresting the fall of an individual. These range from lanyards with no shock absorbing device to lanyards with shock absorbers that are made by the stitching of layers of a safety harness together so that a fall is arrested by the breakinq of the stitching to elaborate devices using retractable lanyards to limit free fall distance and clutches or other braking devices to slow down and stop the rotation of the lanyard drum. While all of these devices have proved to be effective in various degrees, there still exists a need for a relatively simple, inexpensive but effective device for arresting the fall of an individual.
Brief Description of the Invention This invention provides a device and a method for arresting the fall of an individual using an elongated webbing wound on a rotatable drum in a housing so that, when a fall occurs and the rotation of the drum is stopped, the fall arresting force is absorbed by the compaction of a plurality of layers of the elongated webbing and in some instances by the compaction of a resilient means between the drum and the first layer of the elongated webbing and when necessary, by the elongation of the portion of the elongated webbing located outside of the housing.
In a preferred embodiment of the invention, the fall arresting device comprises a housing having an opening formed therein. A drum is rotatably mounted in the housing and has an axis of rotation. An elongated webbing is wound on the drum and has one end secured to the drum and the other end thereof passing out through the opening. A connecting device is secured to the other end of the elongated webbing for connecting the other end where desired, such as to a harness on a worker. Force applying means, such as a falling body, apply a force on the connecting device to rotate the drum. Stop means are provided for preventing rotation of the drum when a predetermined rotational velocity thereof has been reached. Arresting means are provided for absorbing the fall arrest energy and reducing the deceleration forces applied to the load supporting device.
The stop means comprise at least a portion of the drum having an outer surface having at least one cam thereon. At least one pawl is pivotally mounted at a fixed location on the housing and has a surface in contact with the outer surface. At least one catch is mounted on the drum for rotation therewith. Resilient means are provided for urging the surface of the pawl into contact with the outer surface. The cam is located on a first radian of the axis of rotation of the outer surface spaced in a circumferential direction from a second radian of the axis of rotation of the outer surface passing through the at least one catch in the direction of rotation of the drum. The cam moves the pawl into the engagement zone above the catch at lower than locking speeds and requires the normal action of the spring and pivot pin to pull the pawl out of the engagement zone before the tip of the sperrad catch engages it, thus providing a fail safe system. At a predetermined rotational velocity of the drum, the cam applies sufficient force on the pawl to overcome the resilient means and move the at least one pawl into contact with the at least one catch to prevent rotation of the drum. In a preferred embodiment, there are a plurality of cams, pawls and catches.
Resilient means are provided to act on the drum to apply a resilient force on any portion of the elongated webbing extending out of the housing and to rotate the drum to rewind the extended webbing. The resilient means 2ls2o2s comprise a coiled spring having a plurality of layers with all but a few of the layers having a diameter at least twice the diameter of the central body portion of the drum. The coiled spring has one end secured to the housing at a fixed location and another end secured to the drum for rotation therewith.
The fall arresting means comprise a plurality of layers of the elongated webbing wound on central body portion of the drum. When a fall occurs, the plurality of layers wound on the central body portion of the drum are compressed when the rotation of the drum is stopped.
The fall may further be arrested by the elongation of the portion of the elongated webbing unwound from the drum.
In another embodiment of the invention, resilient means are located between the outer surface of the central body portion of the drum and the first layer of the elongated webbing to provide for additional compaction of the layers of the elongated webbing.
A method is provided for arresting a fall of an individual using a housing having a rotatable drum mounted therein by winding a plurality of layers of an elongated webbing on the drum; securing an inner end portion of the elongated webbing on the drum; mounting a connecting device on an exposed end portion of the elongated webbing; placing a weight on the connecting device due to the fall to move the connecting device in a downward direction and rotate the drum; stopping the rotation of the drum and compressing a plurality of the 21~2025 `' ~
plurality of layers of the elongated webbing on the drum to arrest the downward movement of the connecting device.
The method further comprises pulling a portion of the elongated webbing out of the housing and stretching the portion of the elongated webbing pulled out of the housing to aid in arresting the downward movement of the connecting device in the event of a fall.
In another preferred embodiment of the invention, means are provided for attaching a fall arresting device to a harness of the type described in United States Patent No. 4,712,513. The attachment means comprise a D-ring attached to the harness and secured to a nozzle secured between the front and rear cover plates with a portion of the nozzle extending through the D-ring.
Locking means are provided on the nozzle for permitting movement of the D-ring over the portion of the nozzle but preventing removal of the D-ring after the D-ring has passed over the portion of the nozzle. Abutment means are provided on another portion of the nozzle for preventing movement of the D-ring over the another portion.
In another preferred embodiment of the invention, additional locking means are provided for urging the D-ring into contact with the locking means.
Brief Description of the Drawings Preferred embodiments of the invention are illustrated in the drawings in which:
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Fig. 1 is a rear elevational view of the invention with the cover removed;
Fig. 2 is a cross-sectional view taken on the line 2-2 of Fig. 1 with some parts removed;
Fig. 3 is an elevational view of the stop means of this invention;
Fig. 4 is an elevational view of a cover of this invention;
Fig. 5 is an elevational view of the housing of this invention;
Fig. 6 is a cross-sectional view taken on the line 6-6 of Fig. 5;
Fig. 7 is an elevational view of the spring mounting of this invention;
Figs. 8 and 9 are elevational views of the nozzle assembly of this invention;
Figs. 10 illustrates the drum attachment end of the webbing;
Fig. 11 illustrates one embodiment of the invention with a portion of the webbing in contact with the drum;
Fig. 12 illustrates another embodiment of the invention with a steel spring between the drum and a portion of the webbing;
Fig. 13 illustrates another embodiment of the invention with a strip of an elastomeric material between the drum and a portion of the webbing;
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Fig. 14 is an elevational view with parts in section illustrating another preferred embodiment of the invention;
Fig. 15 is a side elevational view of Fig. 14;
Fig. 16 is a top plan view of Fig. 14;
Fig. 17 is a perspective view of Fig. 14;
Fig. 18 is a top plan view of a D-ring;
Fig. 19 is an elevational view with parts in section illustrating a double action single locking attachment of the invention with the D-ring in a locked position;
Fig. 20 is an elevational view with parts in section illustrating the D-ring before it is moved into the locked position; and Fig. 21 is a top plan view of Fig. 19.
Detailed Description of the Invention In Figs. 1 and 2, there is illustrated a fall arrester 2 of this invention having an anchorage mount configuration. The fall arrester 2 has a housing 4 having an arcuate extent, Fig. 5, of about 290 degrees so as to provide for an opening 6. The housing 4 has a plurality of circumferentially spaced apart threaded openings 8 for purposes described below. A front cover plate 10 and a rear cover plate 12, Figs. 2 and 4, each have a plurality of circumferentially spaced apart openings 14 so that headed threaded bolts 16 may pass through the openings 14 and be threadedly secured in the threaded openings 8 to secure the front 10 and rear 12 cover plates to the housing 4.
A drum 20 is mounted for rotation about an axis of rotation in the housing 4 and has a central body portion 22 having generally cylindrical inner surfaces 24 and 26 on either side of a central radially inwardly extending flange 28. Bearings 30 and 32 are mounted on the generally cylindrical surfaces 24 and 26. A fixed shaft 34 has a generally cylindrical surface 36 which is in contact with the other side of the bearings 30 and 32 to allow for rotation of the drum 20. The ends of the shaft 34 fit into recesses 38 and 40 in the front 10 and rear 12 cover plates and are secured therein by headed threaded bolts 42 and 44.
An annular plate 50 is secured on the central body portion 22 using a plurality of circumferentially spaced apart headed threaded bolts 52. A flange portion 54 projects radially outwardly from the central body portion 22 and cooperates with the annular plate 50 to define a first cavity 56. An elongated webbing 58 is wound on a generally cylindrical outer surface 60 and is located in the first cavity 56. One end 62 of the elongated webbing 58 is secured to the central body portion by suitable means described below. The other end 64 passes out of the housing 4 through a nozzle 66, explained more fully below. The other end 64 is permanently secured to a portion 68 of the elongated webbing 58. Other portions 70 of the other end 64 are doubled upon themselves and temporarily secured together. A connecting device 72, such as a D-ring, snap hook or other similar devices, is located between the other end 64 and the other portions 70 for connecting the other end 64 where desired, such as to the harness (not shown) of a worker. The inner surfaces of the other portions 70 are distinctively colored so that when sufficient force is placed on the connecting device to arrest a fall, the other portions will be broken open to reveal the colored portions to indicate that the fall arrester 2 has been used.
A second cavity 80 is formed between the annular plate 50 and the front cover plate 10. A coiled spring 82, Figs. 2 and 7, is located in the second cavity 80 and has one end thereof secured to the nozzle, described below, by suitable means (not shown). The other end 86 of the coiled spring 82 is secured in the central body portion 22 so that as the central body portion 22 rotates, the coiled spring 82 is wrapped thereon. The coil spring 82 exerts a varying force of between about 3 pounds on the outer layer of the elongated webbing 58 and about 12 pounds on the inner layer of the elongated webbing 58 on the central body portion 22 tending to keep the elongated webbing 58 wound on the reel 20. The coiled spring 82 is attached to ride in the housing, not the drum, so that in its unwound state substantially all of the coils thereof are adjacent to the housing 4. By securing the coiled spring 82 to ride in the housing rather than the drum, to rotational momentum of the drum ~152025 decreases as the webbing 58 retracts into the drum, thereby reducing the possibility of damage to the webbing and the spring should a unit be accidentally released to retract uncontrollably.
A handle 90 is secured to the housing 4 by suitable means such as headed threaded bolts 91 passing through reinforced openings 92 in the housing 4.
Stop means 100 are illustrated in Figs. 1-3. An axially outer portion 102 of the central body portion 22 is provided with an outer surface having a plurality of linear extending surfaces 104 separated by a plurality of cams 106. A sperrad 108 is secured on the flange portion 54 by a plurality of headed threaded bolts (not shown) passing through circumferentially spaced apart openings (not shown) in the flange portion 54 and threadedly secured in the threaded openings 110. The sperrad 108 has an inner surface having a plurality of catches 112.
A plurality of pawls 114 are pivotally mounted on pivot studs 116 projecting outwardly from the rear cover plate 12. Resilient means 118 urge a surface 120 of each pawl 114 into contact with the linear surfaces 104 of the cams 106. As illustrated in Fig. 3, a radian A passing through the center point of a cam 106 is located behind a radian B passing through the tip of a catch 112 in the direction of rotation of the drums 20. When the surface 120 of the pawl 114 is in contact with the cam 106, the distance between the axis of the drum 20 and the tip 115 of the pawl 114 is greater than the distance between the axis of the drum 20 and the tip of the catch 112 as indicated by the dashed lines in Fig. 3 and referred to as the engagement zone. However, as the drum 20 rotates, the surface 120 of the pawl 114 moves onto the linear surface 104 so that the distance between the axis of the drum 20 and the tip 115 of the pawl 114 is less than the distance between the axis of the drum 20 and the tip of the catch 112. The cam moves the pawl into the engagement zone at lower than locking speeds and requires the normal action of the spring and pivot pin to pull the pawl out of the engagement zone before the tip of the sperrad catch engages it, thus providing a fail safe feature. This permits the normal extension of the webbing 58 as required by a worker. This is accomplished by the circumferentially spaced apart locations of the cams 106 and the catches 112. However, when the drum 20 is rotating at a sufficiently high speed such as when a fall occurs, the inertial force exerted by the resilient means 118 will be overcome by the force exerted on the pawls 114 by the cams 106 so that the pawls 114 remain extended and will enter into the catches 112 and stop the rotation of the drum. If something should happen to the resilient means 118, the pawls 114 would remain as positioned by the cams 106 so that the pawls 114 would enter into the catches 112 and prevent rotation of the drum 20 and thus provide for a fail safe condition.
The portions forming the nozzle 66 are illustrated in Figs. 1, 8 and 9. The nozzle 66 comprises two V-shaped members 122 and 124, having slots 126 and 128 formed therein. The slots 126 and 128 are in alignment to form an opening for the other end 64 of the elongated webbing 58 to pass through. Each of the V-shaped members 122 and 124 are provided with passageways 130 extending therethrough so that headed threaded bolts 132 may be passed through openings 134 in the front 10 and rear 12 cover plates and be secured in threaded openings in studs (not shown) located in the passageways 130 and extending between and in contact with the front and rear cover plates 10 and 12. Other passageways 138 are formed in each of the V-shaped members 122 and 124 and extend therethrough so that bolts 140 may be passed through openings 142 in the front 10 and rear 12 cover plates and be secured.in threaded openings in studs (not shown) located in the passageways 138 and extending between and in contact with the front and rear cover plates 10 and 12.
The one end 62 of the webbing 58 is illustrated in Fig. 10. A portion 150 is folded back on another portion 152 and partially stitched together to form a loop 154.
In Fig. 11, there is illustrated one embodiment of the invention for securing the one end 62 to the central body portion 22. The central body portion 22 has an inner portion 156 and a spaced apart outer portion 158 so as to form a cavity 160. An opening 162 in the outer portion 158 provides access to the cavity 160. The outer portion 158 has threaded openings 164 for receiving the bolts 52.
` 2152025 In securing the webbing 58 to the central body portion 22, the loop 154 is placed around the inner portion 156 and the portions 150 and 152 pass through the opening 162 and are then wound around the outer portion 158.
Another embodiment of the invention is illustrated in Fig. 12. A steel spring 166 is located between the outer surface 168 of the outer portion 158 and the first wrap 150 and 152 of the webbing 58 and is used to provide for additional compression of the webbing 58 on the drum 20. The steel spring 166 has a plurality of spaced apart sections 170 in contact with the outer surface 168 and another plurality of spaced apart sections 172 spaced from the outer surface 168. The steel spring 166 has arcuate shaped end portions 174 for securing it to the outer portion 158. The steel spring 166 provides for additional compaction of the layers of the elongated webbing in the event of a fall.
Another embodiment of the invention is illustrated in Fig. 13. A strip of elastomeric material 176, such as foamed rubber or other materials having similar characteristics, is located between the outer surface 168 and the first wrap 150 and 152 and is used to provide for additional compression o the webbing 58 on the drum 20.
The strip of elastomeric material 176 provides for additional compaction of the layers of the elongated webbing in the event of a fall.
In the assembly of the arresting device, the bearings 30 and 32 are inserted into the central body ~, portion 22. The sperrad 108 is secured to the flange portion 54. The one end 62 of the elongated webbing 58 is secured to the generally cylindrical outer surface 60 and then wound thereon. The annular plate 50 is then secured to the central body portion 22. A portion of the elongated webbing 58 prior to the other portions 70 is located in the slots 126 and 128 and the back cover plate 12 is placed in position. One end of the coiled spring 82 is secured to the nozzle 122 or 124 and the other end 86 is secured in a notch in the central body portion 22.
At least one wrap of the coil spring 82 is used to retain the other end 86 in the notch in the central body portion 22. The front cover plate 10 is then positioned on the housing 4 and the various bolts are used to secure the arresting device 2 in an assembled condition. A force is applied to the load supporting member 72 to pull all of the elongated webbing 58 out of the housing 4 and then the spring 82 is used to retract the elongated webbing 58.
In use of the anchorage mount configuration, the handle 90 is secured to a fixed support or a life line (not shown) and the connecting device 70 is secured to the safety harness (not shown) on a worker. The elongated webbing 58 has a length of about twenty-one feet to allow for ordinary movement of the worker. In the event of an accident or other reasons, if the worker starts to fall, a greater force is applied to the connecting device 72 so as to accelerate the rotation of the drum 20. The acceleration of the drum 20 is rapid so that, when five to seven inches of the elongated webbing 58 have passed through the nozzle 66, the pawls 114 have moved into the catches 112 to prevent rotation of the drum 20. The deceleration force of the fall is then reduced by the fall arresting energy being absorbed by the compaction of the elongated webbing 58 on the drum 20 and, when necessary, the elongation of the portion of the elongated webbing 58 passing through the nozzle 66.
Also, the deformation of the steel spring 166 or the elastomeric material 176 will also provide for additional compression of the webbing 58 on the central body portion 22. In some instance, an external shock absorber, such as that illustrated in United States Patent No.
4,618,026, which is incorporated herein by reference thereto, may be secured to the load supporting device 72.
The following table lists various parameters that must be met by any fall arresting device.
Table 1 Test ParameterANSI Z359.1OSHA 1910. 66 CSA
Z259.2 CEN
Test Weight (lbs.)220* 220 220**
Free Fall (ft.) 0* 0 2**
Freq. Filter (hz.) 100 120* No spec. 60**
Cable Extraction (ft.) 3* No spec. 2 Allowables:
Force (lbf.) 1,800 1,260* 2,700 1,350**
Extension (in.) 54 42* 40**
220 The ANSI and OSHA are United States requirements; the CSA is Canadian requirements and the CEN is European requirements. A series of tests were conducted using various materials as the webbing 58. The parameters indicated by the single asterisk were used to determine whether or not a material passes a O free fall and the parameters indicated by the double asterisks were used to determine whether or not a material passed at 2 feet of free fall. In addition to the test at three feet of initial webbing extraction, tests were conducted at eight, thirteen and eighteen feet of initial webbing extraction. Two materials that passed the tests were a nylon webbing marketed by the Elizabeth Webbing Company under the trade designation N-7649 which had a width of 1.0 inch and a thickness of 0. 085 inch and a nylon webbing marketed by the Murdock Webbing Company under the trade designation No. 11210 which had a width of 0. 9375 inch and a thickness of 0. 076 inch.
In Figs. 14-16, there is illustrated a back pack configuration for attaching the fall arrester 2 to the rear plate of the safety harness illustrated in United States Patent No. 4,712,513 which is incorporated herein by reference thereto or any other similar safety harness.
A D-ring 180, Fig. 18, is used instead of the ring illustrated in the ' 513 patent.
A nozzle 182, Fig. 17, comprises two members 184 and 186 which have passageways 188 and 190 similar to the passageways 130 and 128 so that the members 184 and 186 may be secured to the front and rear cover plates 10 and 12 in the same manner as the members 122 and 124. When joined together, the members 184 and 186 have a rectangular portion 192 and a cylindrical portion 194. A
recess 196 is formed in the member 184 and a recess 198 is formed in the member 186 so that when the members 184 and 186 are joined together they form a slot for the passageway of the elongated webbing 58. Two spaced apart openings 200 and 202, Fig. 16, are formed in the member 184 and two spaced apart openings 204 and 206 are formed in the member 186. A pivot pin 208 is located in the openings 200 and 204 and another pivot pin 210 is located in the openings 202 and 206. Two spaced apart recesses 212 and 214 are formed in the member 184 and two spaced apart recesses 216 and 218 are formed in the member 186.
A locking lever 220 is located in the recesses 212 and 216 and is mounted for pivotal movement on the pivot pin 208 and is urged outwardly by a spring 222 located in recesses (not shown) in the members 184 and 186. Another locking lever 224 is located in recesses 214 and 218 and is mounted for pivotal movement on the pivot pin 210 and is urged outwardly by a spring 226 located in recesses (not shown) in the members 184 and 186.
A recess 230 is formed in the member 184 and a plate 232 is located in the recess 230. A portion 234 projects from the plate 232 and is located in a recess in the cylindrical portion 194 and has an arcuate hook portion 236 for purposes described below. The plate 232 has two abutment surfaces 238 and 240. A recess 242 is formed in the member 186 and a plate 244 is located in the recess.
A portion 245 of the plate 244 projects from the plate 244 and is located in a recess in the cylindrical portion 194. The plate 244 has two abutment surfaces 246 and 248. The plates 232 and 244 are secured in the recesses 230 and 242 by headed threaded bolts 250 passing through openings in the front and rear cover plates 10 and 12 and secured in threaded openings 252 in studs 254 located in passageways 256 and 258 formed in the members 184 and 186 and in contact with the plates 232 and 244.
The D-ring 180 has three straight sides 260, 262 and 264 and an arcuate side 266. A center partition 268 forms a rectangular opening 270 and a circular opening 272 and is thinner than the straight sides 260, 262 and 264 and arcuate side 268.
In use of the back pack configuration, the crossing portions of the harness as illustrated in the '513 patent are located in the rectangular opening 270. The arcuate side 266 is placed under the hook portion 236 and the D-ring 180 is moved over the cylindrical portion 194. As the D-ring 180 moves over the cylindrical portion 194, it pushes the locking levers 220 and 224 inwardly. When the D-ring 180 has passed the locking levers 220 and 224, the springs 222 and 226 move the locking levers 220 and 224 outwardly so that the end portions 274 and 276 will be superposed over the straight sides 260 and 264 to prevent the accidental removal of the D-ring 180. Portions of the center partition 268 are in contact with the abutment surfaces 246 and 248. Since the center partition 268 is thinner, this results in a slight angle for the D-ring.
If desired, this slight angular relationship can be changed by raising the abutment surfaces 246 and 248.
Portions of the arcuate side 266 are in contact with the abutment surfaces 238 and 240. If a fall occurs, the D-ring 180 applies a force on the abutment surfaces 246 and 248 and pivotal movement of the D-ring 180 is prevented by the hook portion 236 and the arcuate side 266.
Another preferred embodiment of the invention is illustrated in Figs. 19-21 and is to be used in association with the harness in United States Patent No.
4,712,513 or any other similar safety harness. Portions of the embodiment of Figs. 19-21 are similar to portions of the embodiment illustrated in Figs. 14-18 and have been given the same reference numerals. This embodiment requires a double action to release the D-ring as required for use with double action single locking snap hooks.
A pair of spaced apart recesses 280 are formed in the member 186 and a mating pair of spaced apart recesses 282 are formed in the member 184. Inverted L-shaped metal plates 284 are located in the recesses 280 and 282.
The pivot pins 206 and 208 pass through openings in the inverted L-shaped metal plates 284. Threaded metal bolts 286 pass through passageways in the members 184 and 186 and are threaded into opposite ends of a common threaded nut 288.
Resilient means 290 are provided for urging the portions 260 and 264 of the D-ring 180 into the locking levers 220 and 224 or for maintaining the locking levers in a retracted position. A sleeve having a generally cylindrical portion 292 and a flange portion 294 is mounted for sliding movement over the cylindrical portion 194 of the members 184 and 186. A coiled spring 295 has a first coil 296 secured by a press fit to the cylindrical portion 194 and a second coil 298 secured by a press fit to the cylindrical portion 292. Under normal conditions, the coiled spring 195 will hold the cylindrical portion 292 at a location to hold the locking levers 220 and 224 in a retracted position as illustrated in Fig. 20 wherein the D-ring has been moved into contact with the flange portion 294.
In use of the back pack configuration, a force is applied to the portions 260 and 264 of the D-ring 180 to move them over a portion of the cylindrical portion 194 and moved into contact with the flange portion 294.
Continued movement of the portions 260 and 264 compresses the coiled spring 295 and the movement of the portions 260 and 264 is continued until the locking levers 220 and 224 are urged outwardly by the springs 222 and 226.
Outward movement of the locking levers 220 and 224 is halted when portions thereof contact abutment surfaces 300 and 302. The force is removed from the portions 260 and 264 and the coiled spring 295 urges the portions 260 and 264 in contact with the locking levers 220 and 224.
Since the center partition 268 is thinner, there will be a slight angular relationship of the D-ring. When it is desired to remove the fall arrester 2, two distinct and separate actions are required. First, the D-ring must be pushed down to disengage the levers 220 and 224. Second, the levers 220 and 224 must be moved inwardly and then the D-ring can slide up and over the levers 220 and 224.
The coiled spring 295 moves the portions 260 and 264 and the cylindrical portion 292 over the cylindrical portion 194 until they reach the location illustrated in Fig. 20.
At that time, the portions 260 and 264 are removed from the portion of the cylindrical portion 194.
While illustrative and presently preferred embodiments of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.
Resilient means are provided to act on the drum to apply a resilient force on any portion of the elongated webbing extending out of the housing and to rotate the drum to rewind the extended webbing. The resilient means 2ls2o2s comprise a coiled spring having a plurality of layers with all but a few of the layers having a diameter at least twice the diameter of the central body portion of the drum. The coiled spring has one end secured to the housing at a fixed location and another end secured to the drum for rotation therewith.
The fall arresting means comprise a plurality of layers of the elongated webbing wound on central body portion of the drum. When a fall occurs, the plurality of layers wound on the central body portion of the drum are compressed when the rotation of the drum is stopped.
The fall may further be arrested by the elongation of the portion of the elongated webbing unwound from the drum.
In another embodiment of the invention, resilient means are located between the outer surface of the central body portion of the drum and the first layer of the elongated webbing to provide for additional compaction of the layers of the elongated webbing.
A method is provided for arresting a fall of an individual using a housing having a rotatable drum mounted therein by winding a plurality of layers of an elongated webbing on the drum; securing an inner end portion of the elongated webbing on the drum; mounting a connecting device on an exposed end portion of the elongated webbing; placing a weight on the connecting device due to the fall to move the connecting device in a downward direction and rotate the drum; stopping the rotation of the drum and compressing a plurality of the 21~2025 `' ~
plurality of layers of the elongated webbing on the drum to arrest the downward movement of the connecting device.
The method further comprises pulling a portion of the elongated webbing out of the housing and stretching the portion of the elongated webbing pulled out of the housing to aid in arresting the downward movement of the connecting device in the event of a fall.
In another preferred embodiment of the invention, means are provided for attaching a fall arresting device to a harness of the type described in United States Patent No. 4,712,513. The attachment means comprise a D-ring attached to the harness and secured to a nozzle secured between the front and rear cover plates with a portion of the nozzle extending through the D-ring.
Locking means are provided on the nozzle for permitting movement of the D-ring over the portion of the nozzle but preventing removal of the D-ring after the D-ring has passed over the portion of the nozzle. Abutment means are provided on another portion of the nozzle for preventing movement of the D-ring over the another portion.
In another preferred embodiment of the invention, additional locking means are provided for urging the D-ring into contact with the locking means.
Brief Description of the Drawings Preferred embodiments of the invention are illustrated in the drawings in which:
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Fig. 1 is a rear elevational view of the invention with the cover removed;
Fig. 2 is a cross-sectional view taken on the line 2-2 of Fig. 1 with some parts removed;
Fig. 3 is an elevational view of the stop means of this invention;
Fig. 4 is an elevational view of a cover of this invention;
Fig. 5 is an elevational view of the housing of this invention;
Fig. 6 is a cross-sectional view taken on the line 6-6 of Fig. 5;
Fig. 7 is an elevational view of the spring mounting of this invention;
Figs. 8 and 9 are elevational views of the nozzle assembly of this invention;
Figs. 10 illustrates the drum attachment end of the webbing;
Fig. 11 illustrates one embodiment of the invention with a portion of the webbing in contact with the drum;
Fig. 12 illustrates another embodiment of the invention with a steel spring between the drum and a portion of the webbing;
Fig. 13 illustrates another embodiment of the invention with a strip of an elastomeric material between the drum and a portion of the webbing;
215202~
Fig. 14 is an elevational view with parts in section illustrating another preferred embodiment of the invention;
Fig. 15 is a side elevational view of Fig. 14;
Fig. 16 is a top plan view of Fig. 14;
Fig. 17 is a perspective view of Fig. 14;
Fig. 18 is a top plan view of a D-ring;
Fig. 19 is an elevational view with parts in section illustrating a double action single locking attachment of the invention with the D-ring in a locked position;
Fig. 20 is an elevational view with parts in section illustrating the D-ring before it is moved into the locked position; and Fig. 21 is a top plan view of Fig. 19.
Detailed Description of the Invention In Figs. 1 and 2, there is illustrated a fall arrester 2 of this invention having an anchorage mount configuration. The fall arrester 2 has a housing 4 having an arcuate extent, Fig. 5, of about 290 degrees so as to provide for an opening 6. The housing 4 has a plurality of circumferentially spaced apart threaded openings 8 for purposes described below. A front cover plate 10 and a rear cover plate 12, Figs. 2 and 4, each have a plurality of circumferentially spaced apart openings 14 so that headed threaded bolts 16 may pass through the openings 14 and be threadedly secured in the threaded openings 8 to secure the front 10 and rear 12 cover plates to the housing 4.
A drum 20 is mounted for rotation about an axis of rotation in the housing 4 and has a central body portion 22 having generally cylindrical inner surfaces 24 and 26 on either side of a central radially inwardly extending flange 28. Bearings 30 and 32 are mounted on the generally cylindrical surfaces 24 and 26. A fixed shaft 34 has a generally cylindrical surface 36 which is in contact with the other side of the bearings 30 and 32 to allow for rotation of the drum 20. The ends of the shaft 34 fit into recesses 38 and 40 in the front 10 and rear 12 cover plates and are secured therein by headed threaded bolts 42 and 44.
An annular plate 50 is secured on the central body portion 22 using a plurality of circumferentially spaced apart headed threaded bolts 52. A flange portion 54 projects radially outwardly from the central body portion 22 and cooperates with the annular plate 50 to define a first cavity 56. An elongated webbing 58 is wound on a generally cylindrical outer surface 60 and is located in the first cavity 56. One end 62 of the elongated webbing 58 is secured to the central body portion by suitable means described below. The other end 64 passes out of the housing 4 through a nozzle 66, explained more fully below. The other end 64 is permanently secured to a portion 68 of the elongated webbing 58. Other portions 70 of the other end 64 are doubled upon themselves and temporarily secured together. A connecting device 72, such as a D-ring, snap hook or other similar devices, is located between the other end 64 and the other portions 70 for connecting the other end 64 where desired, such as to the harness (not shown) of a worker. The inner surfaces of the other portions 70 are distinctively colored so that when sufficient force is placed on the connecting device to arrest a fall, the other portions will be broken open to reveal the colored portions to indicate that the fall arrester 2 has been used.
A second cavity 80 is formed between the annular plate 50 and the front cover plate 10. A coiled spring 82, Figs. 2 and 7, is located in the second cavity 80 and has one end thereof secured to the nozzle, described below, by suitable means (not shown). The other end 86 of the coiled spring 82 is secured in the central body portion 22 so that as the central body portion 22 rotates, the coiled spring 82 is wrapped thereon. The coil spring 82 exerts a varying force of between about 3 pounds on the outer layer of the elongated webbing 58 and about 12 pounds on the inner layer of the elongated webbing 58 on the central body portion 22 tending to keep the elongated webbing 58 wound on the reel 20. The coiled spring 82 is attached to ride in the housing, not the drum, so that in its unwound state substantially all of the coils thereof are adjacent to the housing 4. By securing the coiled spring 82 to ride in the housing rather than the drum, to rotational momentum of the drum ~152025 decreases as the webbing 58 retracts into the drum, thereby reducing the possibility of damage to the webbing and the spring should a unit be accidentally released to retract uncontrollably.
A handle 90 is secured to the housing 4 by suitable means such as headed threaded bolts 91 passing through reinforced openings 92 in the housing 4.
Stop means 100 are illustrated in Figs. 1-3. An axially outer portion 102 of the central body portion 22 is provided with an outer surface having a plurality of linear extending surfaces 104 separated by a plurality of cams 106. A sperrad 108 is secured on the flange portion 54 by a plurality of headed threaded bolts (not shown) passing through circumferentially spaced apart openings (not shown) in the flange portion 54 and threadedly secured in the threaded openings 110. The sperrad 108 has an inner surface having a plurality of catches 112.
A plurality of pawls 114 are pivotally mounted on pivot studs 116 projecting outwardly from the rear cover plate 12. Resilient means 118 urge a surface 120 of each pawl 114 into contact with the linear surfaces 104 of the cams 106. As illustrated in Fig. 3, a radian A passing through the center point of a cam 106 is located behind a radian B passing through the tip of a catch 112 in the direction of rotation of the drums 20. When the surface 120 of the pawl 114 is in contact with the cam 106, the distance between the axis of the drum 20 and the tip 115 of the pawl 114 is greater than the distance between the axis of the drum 20 and the tip of the catch 112 as indicated by the dashed lines in Fig. 3 and referred to as the engagement zone. However, as the drum 20 rotates, the surface 120 of the pawl 114 moves onto the linear surface 104 so that the distance between the axis of the drum 20 and the tip 115 of the pawl 114 is less than the distance between the axis of the drum 20 and the tip of the catch 112. The cam moves the pawl into the engagement zone at lower than locking speeds and requires the normal action of the spring and pivot pin to pull the pawl out of the engagement zone before the tip of the sperrad catch engages it, thus providing a fail safe feature. This permits the normal extension of the webbing 58 as required by a worker. This is accomplished by the circumferentially spaced apart locations of the cams 106 and the catches 112. However, when the drum 20 is rotating at a sufficiently high speed such as when a fall occurs, the inertial force exerted by the resilient means 118 will be overcome by the force exerted on the pawls 114 by the cams 106 so that the pawls 114 remain extended and will enter into the catches 112 and stop the rotation of the drum. If something should happen to the resilient means 118, the pawls 114 would remain as positioned by the cams 106 so that the pawls 114 would enter into the catches 112 and prevent rotation of the drum 20 and thus provide for a fail safe condition.
The portions forming the nozzle 66 are illustrated in Figs. 1, 8 and 9. The nozzle 66 comprises two V-shaped members 122 and 124, having slots 126 and 128 formed therein. The slots 126 and 128 are in alignment to form an opening for the other end 64 of the elongated webbing 58 to pass through. Each of the V-shaped members 122 and 124 are provided with passageways 130 extending therethrough so that headed threaded bolts 132 may be passed through openings 134 in the front 10 and rear 12 cover plates and be secured in threaded openings in studs (not shown) located in the passageways 130 and extending between and in contact with the front and rear cover plates 10 and 12. Other passageways 138 are formed in each of the V-shaped members 122 and 124 and extend therethrough so that bolts 140 may be passed through openings 142 in the front 10 and rear 12 cover plates and be secured.in threaded openings in studs (not shown) located in the passageways 138 and extending between and in contact with the front and rear cover plates 10 and 12.
The one end 62 of the webbing 58 is illustrated in Fig. 10. A portion 150 is folded back on another portion 152 and partially stitched together to form a loop 154.
In Fig. 11, there is illustrated one embodiment of the invention for securing the one end 62 to the central body portion 22. The central body portion 22 has an inner portion 156 and a spaced apart outer portion 158 so as to form a cavity 160. An opening 162 in the outer portion 158 provides access to the cavity 160. The outer portion 158 has threaded openings 164 for receiving the bolts 52.
` 2152025 In securing the webbing 58 to the central body portion 22, the loop 154 is placed around the inner portion 156 and the portions 150 and 152 pass through the opening 162 and are then wound around the outer portion 158.
Another embodiment of the invention is illustrated in Fig. 12. A steel spring 166 is located between the outer surface 168 of the outer portion 158 and the first wrap 150 and 152 of the webbing 58 and is used to provide for additional compression of the webbing 58 on the drum 20. The steel spring 166 has a plurality of spaced apart sections 170 in contact with the outer surface 168 and another plurality of spaced apart sections 172 spaced from the outer surface 168. The steel spring 166 has arcuate shaped end portions 174 for securing it to the outer portion 158. The steel spring 166 provides for additional compaction of the layers of the elongated webbing in the event of a fall.
Another embodiment of the invention is illustrated in Fig. 13. A strip of elastomeric material 176, such as foamed rubber or other materials having similar characteristics, is located between the outer surface 168 and the first wrap 150 and 152 and is used to provide for additional compression o the webbing 58 on the drum 20.
The strip of elastomeric material 176 provides for additional compaction of the layers of the elongated webbing in the event of a fall.
In the assembly of the arresting device, the bearings 30 and 32 are inserted into the central body ~, portion 22. The sperrad 108 is secured to the flange portion 54. The one end 62 of the elongated webbing 58 is secured to the generally cylindrical outer surface 60 and then wound thereon. The annular plate 50 is then secured to the central body portion 22. A portion of the elongated webbing 58 prior to the other portions 70 is located in the slots 126 and 128 and the back cover plate 12 is placed in position. One end of the coiled spring 82 is secured to the nozzle 122 or 124 and the other end 86 is secured in a notch in the central body portion 22.
At least one wrap of the coil spring 82 is used to retain the other end 86 in the notch in the central body portion 22. The front cover plate 10 is then positioned on the housing 4 and the various bolts are used to secure the arresting device 2 in an assembled condition. A force is applied to the load supporting member 72 to pull all of the elongated webbing 58 out of the housing 4 and then the spring 82 is used to retract the elongated webbing 58.
In use of the anchorage mount configuration, the handle 90 is secured to a fixed support or a life line (not shown) and the connecting device 70 is secured to the safety harness (not shown) on a worker. The elongated webbing 58 has a length of about twenty-one feet to allow for ordinary movement of the worker. In the event of an accident or other reasons, if the worker starts to fall, a greater force is applied to the connecting device 72 so as to accelerate the rotation of the drum 20. The acceleration of the drum 20 is rapid so that, when five to seven inches of the elongated webbing 58 have passed through the nozzle 66, the pawls 114 have moved into the catches 112 to prevent rotation of the drum 20. The deceleration force of the fall is then reduced by the fall arresting energy being absorbed by the compaction of the elongated webbing 58 on the drum 20 and, when necessary, the elongation of the portion of the elongated webbing 58 passing through the nozzle 66.
Also, the deformation of the steel spring 166 or the elastomeric material 176 will also provide for additional compression of the webbing 58 on the central body portion 22. In some instance, an external shock absorber, such as that illustrated in United States Patent No.
4,618,026, which is incorporated herein by reference thereto, may be secured to the load supporting device 72.
The following table lists various parameters that must be met by any fall arresting device.
Table 1 Test ParameterANSI Z359.1OSHA 1910. 66 CSA
Z259.2 CEN
Test Weight (lbs.)220* 220 220**
Free Fall (ft.) 0* 0 2**
Freq. Filter (hz.) 100 120* No spec. 60**
Cable Extraction (ft.) 3* No spec. 2 Allowables:
Force (lbf.) 1,800 1,260* 2,700 1,350**
Extension (in.) 54 42* 40**
220 The ANSI and OSHA are United States requirements; the CSA is Canadian requirements and the CEN is European requirements. A series of tests were conducted using various materials as the webbing 58. The parameters indicated by the single asterisk were used to determine whether or not a material passes a O free fall and the parameters indicated by the double asterisks were used to determine whether or not a material passed at 2 feet of free fall. In addition to the test at three feet of initial webbing extraction, tests were conducted at eight, thirteen and eighteen feet of initial webbing extraction. Two materials that passed the tests were a nylon webbing marketed by the Elizabeth Webbing Company under the trade designation N-7649 which had a width of 1.0 inch and a thickness of 0. 085 inch and a nylon webbing marketed by the Murdock Webbing Company under the trade designation No. 11210 which had a width of 0. 9375 inch and a thickness of 0. 076 inch.
In Figs. 14-16, there is illustrated a back pack configuration for attaching the fall arrester 2 to the rear plate of the safety harness illustrated in United States Patent No. 4,712,513 which is incorporated herein by reference thereto or any other similar safety harness.
A D-ring 180, Fig. 18, is used instead of the ring illustrated in the ' 513 patent.
A nozzle 182, Fig. 17, comprises two members 184 and 186 which have passageways 188 and 190 similar to the passageways 130 and 128 so that the members 184 and 186 may be secured to the front and rear cover plates 10 and 12 in the same manner as the members 122 and 124. When joined together, the members 184 and 186 have a rectangular portion 192 and a cylindrical portion 194. A
recess 196 is formed in the member 184 and a recess 198 is formed in the member 186 so that when the members 184 and 186 are joined together they form a slot for the passageway of the elongated webbing 58. Two spaced apart openings 200 and 202, Fig. 16, are formed in the member 184 and two spaced apart openings 204 and 206 are formed in the member 186. A pivot pin 208 is located in the openings 200 and 204 and another pivot pin 210 is located in the openings 202 and 206. Two spaced apart recesses 212 and 214 are formed in the member 184 and two spaced apart recesses 216 and 218 are formed in the member 186.
A locking lever 220 is located in the recesses 212 and 216 and is mounted for pivotal movement on the pivot pin 208 and is urged outwardly by a spring 222 located in recesses (not shown) in the members 184 and 186. Another locking lever 224 is located in recesses 214 and 218 and is mounted for pivotal movement on the pivot pin 210 and is urged outwardly by a spring 226 located in recesses (not shown) in the members 184 and 186.
A recess 230 is formed in the member 184 and a plate 232 is located in the recess 230. A portion 234 projects from the plate 232 and is located in a recess in the cylindrical portion 194 and has an arcuate hook portion 236 for purposes described below. The plate 232 has two abutment surfaces 238 and 240. A recess 242 is formed in the member 186 and a plate 244 is located in the recess.
A portion 245 of the plate 244 projects from the plate 244 and is located in a recess in the cylindrical portion 194. The plate 244 has two abutment surfaces 246 and 248. The plates 232 and 244 are secured in the recesses 230 and 242 by headed threaded bolts 250 passing through openings in the front and rear cover plates 10 and 12 and secured in threaded openings 252 in studs 254 located in passageways 256 and 258 formed in the members 184 and 186 and in contact with the plates 232 and 244.
The D-ring 180 has three straight sides 260, 262 and 264 and an arcuate side 266. A center partition 268 forms a rectangular opening 270 and a circular opening 272 and is thinner than the straight sides 260, 262 and 264 and arcuate side 268.
In use of the back pack configuration, the crossing portions of the harness as illustrated in the '513 patent are located in the rectangular opening 270. The arcuate side 266 is placed under the hook portion 236 and the D-ring 180 is moved over the cylindrical portion 194. As the D-ring 180 moves over the cylindrical portion 194, it pushes the locking levers 220 and 224 inwardly. When the D-ring 180 has passed the locking levers 220 and 224, the springs 222 and 226 move the locking levers 220 and 224 outwardly so that the end portions 274 and 276 will be superposed over the straight sides 260 and 264 to prevent the accidental removal of the D-ring 180. Portions of the center partition 268 are in contact with the abutment surfaces 246 and 248. Since the center partition 268 is thinner, this results in a slight angle for the D-ring.
If desired, this slight angular relationship can be changed by raising the abutment surfaces 246 and 248.
Portions of the arcuate side 266 are in contact with the abutment surfaces 238 and 240. If a fall occurs, the D-ring 180 applies a force on the abutment surfaces 246 and 248 and pivotal movement of the D-ring 180 is prevented by the hook portion 236 and the arcuate side 266.
Another preferred embodiment of the invention is illustrated in Figs. 19-21 and is to be used in association with the harness in United States Patent No.
4,712,513 or any other similar safety harness. Portions of the embodiment of Figs. 19-21 are similar to portions of the embodiment illustrated in Figs. 14-18 and have been given the same reference numerals. This embodiment requires a double action to release the D-ring as required for use with double action single locking snap hooks.
A pair of spaced apart recesses 280 are formed in the member 186 and a mating pair of spaced apart recesses 282 are formed in the member 184. Inverted L-shaped metal plates 284 are located in the recesses 280 and 282.
The pivot pins 206 and 208 pass through openings in the inverted L-shaped metal plates 284. Threaded metal bolts 286 pass through passageways in the members 184 and 186 and are threaded into opposite ends of a common threaded nut 288.
Resilient means 290 are provided for urging the portions 260 and 264 of the D-ring 180 into the locking levers 220 and 224 or for maintaining the locking levers in a retracted position. A sleeve having a generally cylindrical portion 292 and a flange portion 294 is mounted for sliding movement over the cylindrical portion 194 of the members 184 and 186. A coiled spring 295 has a first coil 296 secured by a press fit to the cylindrical portion 194 and a second coil 298 secured by a press fit to the cylindrical portion 292. Under normal conditions, the coiled spring 195 will hold the cylindrical portion 292 at a location to hold the locking levers 220 and 224 in a retracted position as illustrated in Fig. 20 wherein the D-ring has been moved into contact with the flange portion 294.
In use of the back pack configuration, a force is applied to the portions 260 and 264 of the D-ring 180 to move them over a portion of the cylindrical portion 194 and moved into contact with the flange portion 294.
Continued movement of the portions 260 and 264 compresses the coiled spring 295 and the movement of the portions 260 and 264 is continued until the locking levers 220 and 224 are urged outwardly by the springs 222 and 226.
Outward movement of the locking levers 220 and 224 is halted when portions thereof contact abutment surfaces 300 and 302. The force is removed from the portions 260 and 264 and the coiled spring 295 urges the portions 260 and 264 in contact with the locking levers 220 and 224.
Since the center partition 268 is thinner, there will be a slight angular relationship of the D-ring. When it is desired to remove the fall arrester 2, two distinct and separate actions are required. First, the D-ring must be pushed down to disengage the levers 220 and 224. Second, the levers 220 and 224 must be moved inwardly and then the D-ring can slide up and over the levers 220 and 224.
The coiled spring 295 moves the portions 260 and 264 and the cylindrical portion 292 over the cylindrical portion 194 until they reach the location illustrated in Fig. 20.
At that time, the portions 260 and 264 are removed from the portion of the cylindrical portion 194.
While illustrative and presently preferred embodiments of the invention have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed and that the appended claims are intended to be construed to include such variations except insofar as limited by the prior art.
Claims (32)
1. A fall arrester comprising:
a housing having an opening formed therein;
a drum rotatably mounted in said housing and having an axis of rotation;
an elongated webbing wound on said drum;
said elongated webbing having one end secured to said drum, a plurality of layers wrapped around a portion of said drum and having the other end thereof passing out of said housing through said opening;
connecting means secured to said other end for connecting said other end where desired;
force applying means for applying a force on said connecting means to rotate said drum;
stop means for preventing rotation of said drum when a predetermined rotational velocity thereof has been reached; and arresting means comprising the compression of at least some of said plurality of layers of said elongated webbing for absorbing said force applied to said connecting device.
a housing having an opening formed therein;
a drum rotatably mounted in said housing and having an axis of rotation;
an elongated webbing wound on said drum;
said elongated webbing having one end secured to said drum, a plurality of layers wrapped around a portion of said drum and having the other end thereof passing out of said housing through said opening;
connecting means secured to said other end for connecting said other end where desired;
force applying means for applying a force on said connecting means to rotate said drum;
stop means for preventing rotation of said drum when a predetermined rotational velocity thereof has been reached; and arresting means comprising the compression of at least some of said plurality of layers of said elongated webbing for absorbing said force applied to said connecting device.
2. A fall arrester as in claim 1 wherein said stop means comprlse:
at least a portion of said drum having an outer surface;
at least one cam on said outer surface;
a least one pawl pivotally mounted at a fixed location on said housing and having a surface in contact with said outer surface;
at least one catch mounted on said drum for rotation therewith;
resilient means for urging said surface of said at least one pawl into contact with said outer surface; and said cam being located on a first radian of said axis of rotation spaced in a circumferential direction from a second radian of said axis of rotation passing through said at least one catch in the direction of rotation of said drum.
at least a portion of said drum having an outer surface;
at least one cam on said outer surface;
a least one pawl pivotally mounted at a fixed location on said housing and having a surface in contact with said outer surface;
at least one catch mounted on said drum for rotation therewith;
resilient means for urging said surface of said at least one pawl into contact with said outer surface; and said cam being located on a first radian of said axis of rotation spaced in a circumferential direction from a second radian of said axis of rotation passing through said at least one catch in the direction of rotation of said drum.
3. A fall arrester as in claim 2 wherein:
when said surface of said at least one pawl is in contact with said at least one cam, the distance between said axis of rotation of said drum and the tip of said at least one pawl is greater than the distance between the axis of rotation of said drum and the tip of said at least one catch.
when said surface of said at least one pawl is in contact with said at least one cam, the distance between said axis of rotation of said drum and the tip of said at least one pawl is greater than the distance between the axis of rotation of said drum and the tip of said at least one catch.
4. A fall arrester as in claim 2 wherein:
at a predetermined rotational velocity of said drum, said cam applying sufficient force on said pawl to overcome said resilient means and move said at least one pawl into contact with said at least one catch to prevent rotation of said drum.
at a predetermined rotational velocity of said drum, said cam applying sufficient force on said pawl to overcome said resilient means and move said at least one pawl into contact with said at least one catch to prevent rotation of said drum.
5. A fall arrester as in claim 1 wherein said stop means comprise:
at least a portion of said drum having an outer surface;
said outer surface having a plurality of circumferentially spaced apart cams;
each of said cams having a radius greater than the other portions of said outer surface;
a plurality of pawls pivotally mounted at circumferentially spaced apart fixed locations on said housing;
an annular member mounted on said drum for rotation therewith;
a plurality of circumferentially spaced apart catches projecting radially inwardly from said annular member;
a plurality of resilient means for urging each of said pawls into contact with said outer surface; and each of said cams being located on a radian spaced in a circumferential direction from a radian passing through each of said catches in the direction of rotation of said drum.
at least a portion of said drum having an outer surface;
said outer surface having a plurality of circumferentially spaced apart cams;
each of said cams having a radius greater than the other portions of said outer surface;
a plurality of pawls pivotally mounted at circumferentially spaced apart fixed locations on said housing;
an annular member mounted on said drum for rotation therewith;
a plurality of circumferentially spaced apart catches projecting radially inwardly from said annular member;
a plurality of resilient means for urging each of said pawls into contact with said outer surface; and each of said cams being located on a radian spaced in a circumferential direction from a radian passing through each of said catches in the direction of rotation of said drum.
6. A fall arrester as in claim 5 wherein:
when said surface of each of said pawls is in contact with one of said cams, the distance between the axis of rotation of said drum and the tip of each pawl is greater than the distance between the axis of rotation of said drum and the tip of each catch.
when said surface of each of said pawls is in contact with one of said cams, the distance between the axis of rotation of said drum and the tip of each pawl is greater than the distance between the axis of rotation of said drum and the tip of each catch.
7. A fall arrester as in claim 5 wherein:
at a predetermined velocity of said drum, each of said cams applying sufficient force on each of said pawls to overcome each of said plurality of resilient means and move each of said pawls into contact with one of said catches to prevent rotation of said drum.
at a predetermined velocity of said drum, each of said cams applying sufficient force on each of said pawls to overcome each of said plurality of resilient means and move each of said pawls into contact with one of said catches to prevent rotation of said drum.
8. A device as in claim 1 and further comprising:
resilient means acting on said drum to apply a resilient force on any portion of said elongated webbing extending out of said housing and tending to rotate said drum to rewind said extended webbing.
resilient means acting on said drum to apply a resilient force on any portion of said elongated webbing extending out of said housing and tending to rotate said drum to rewind said extended webbing.
9. A fall arrester as in claim 8 wherein said resilient means comprises:
a coiled spring having more than three coils having a diameter at least twice the diameter of said drum;
said coiled spring having one end secured at a fixed location; and said coiled spring having another end secured to said drum for rotation therewith.
a coiled spring having more than three coils having a diameter at least twice the diameter of said drum;
said coiled spring having one end secured at a fixed location; and said coiled spring having another end secured to said drum for rotation therewith.
10. A fall arrester as in claim 1 wherein:
at least a portion of said elongated webbing being moved out of said housing before actuation of said stop means.
at least a portion of said elongated webbing being moved out of said housing before actuation of said stop means.
11. A fall arrester as in claim 10 wherein said arresting means further comprise:
an elongation of said at least a portion of said elongated webbing.
an elongation of said at least a portion of said elongated webbing.
12. A fall arrester as in claim 1 and further comprising:
said drum having an outer surface on which said elongated webbing is wound;
resilient means located between said outer surface and a portion of said elongated webbing.
said drum having an outer surface on which said elongated webbing is wound;
resilient means located between said outer surface and a portion of said elongated webbing.
13. A fall arrester as in claim 12 wherein said stop means comprise:
at least a portion of said drum having an outer surface;
said outer surface having a plurality of circumferentially spaced apart cams;
each of said cams having a radius greater than the other portions of said outer surface;
a plurality of pawls pivotally mounted at circumferentially spaced apart fixed locations on said housing;
an annular member mounted on said drum for rotation therewith;
a plurality of circumferentially spaced apart catches projecting radially inwardly from said annular member;
a plurality of resilient means for urging each of said pawls into contact with said outer surface; and each of said cams being located on a radian spaced in a circumferential direction from a radian passing through each of said catches in the direction of rotation of said drum.
at least a portion of said drum having an outer surface;
said outer surface having a plurality of circumferentially spaced apart cams;
each of said cams having a radius greater than the other portions of said outer surface;
a plurality of pawls pivotally mounted at circumferentially spaced apart fixed locations on said housing;
an annular member mounted on said drum for rotation therewith;
a plurality of circumferentially spaced apart catches projecting radially inwardly from said annular member;
a plurality of resilient means for urging each of said pawls into contact with said outer surface; and each of said cams being located on a radian spaced in a circumferential direction from a radian passing through each of said catches in the direction of rotation of said drum.
14. A fall arrester as in claim 12 wherein:
said resilient means comprises a steel spring.
said resilient means comprises a steel spring.
15. A device as in claim 13 wherein:
said resilient means comprises a strip of an elastomeric material.
said resilient means comprises a strip of an elastomeric material.
16. A fall arrester as in claim 1 and further comprising:
an external shock absorber connected to said load supporting device and having another connecting means secured thereto.
an external shock absorber connected to said load supporting device and having another connecting means secured thereto.
17. Stop means for preventing the rotation of a drum comprising:
a housing;
a drum rotatably mounted in said housing and having an axis of rotation;
at least a portion of said drum having an outer surface;
at least one cam mounted on said outer surface;
at least one pawl pivotally mounted at a fixed location on said housing and having a surface in contact with said outer surface;
at least one catch mounted on said drum for rotation therewith;
resilient means for urging said surface of said pawl into contact with said outer surface; and said cam being located on a first radian from said axis of rotation and spaced from a second radian of said axis of rotation passing through said catch in the direction of rotation of said drum so that, at a predetermined velocity of said drum, said cam applies sufficient force on said pawl to overcome said resilient force and move said at least one pawl into contact with said catch to prevent rotation of said drum.
a housing;
a drum rotatably mounted in said housing and having an axis of rotation;
at least a portion of said drum having an outer surface;
at least one cam mounted on said outer surface;
at least one pawl pivotally mounted at a fixed location on said housing and having a surface in contact with said outer surface;
at least one catch mounted on said drum for rotation therewith;
resilient means for urging said surface of said pawl into contact with said outer surface; and said cam being located on a first radian from said axis of rotation and spaced from a second radian of said axis of rotation passing through said catch in the direction of rotation of said drum so that, at a predetermined velocity of said drum, said cam applies sufficient force on said pawl to overcome said resilient force and move said at least one pawl into contact with said catch to prevent rotation of said drum.
18. Stop means as in claim 17 wherein:
said at least one pawl comprises a plurality of pawls; and said at least one cam comprises a plurality of cams.
said at least one pawl comprises a plurality of pawls; and said at least one cam comprises a plurality of cams.
19. Stop means as in claim 18 wherein:
when said surface of each of said pawls is in contact with one of said cams, the distance between the axis of rotation of said drum and the tip of each pawl is greater than the distance between the axis of rotation of said drum and the tip of each catch.
when said surface of each of said pawls is in contact with one of said cams, the distance between the axis of rotation of said drum and the tip of each pawl is greater than the distance between the axis of rotation of said drum and the tip of each catch.
20. A method for arresting a fall using a housing having a rotatable drum mounted therein comprising:
winding a plurality of layers of an elongated webbing on said drum;
securing an inner end portion of said elongated webbing on said drum;
securing connecting means on an exposed end portion of said elongated webbing for connecting said elongated webbing where desired;
placing a weight on said connecting means to move said connecting means in a downward direction and to rotate said drum;
stopping the rotation of said drum; and compressing a plurality of said plurality of layers of said elongated webbing on said drum to arrest the downward movement of said connecting means.
winding a plurality of layers of an elongated webbing on said drum;
securing an inner end portion of said elongated webbing on said drum;
securing connecting means on an exposed end portion of said elongated webbing for connecting said elongated webbing where desired;
placing a weight on said connecting means to move said connecting means in a downward direction and to rotate said drum;
stopping the rotation of said drum; and compressing a plurality of said plurality of layers of said elongated webbing on said drum to arrest the downward movement of said connecting means.
21. A method as in claim 20 and further comprising:
pulling a portion of said elongated webbing out of said housing; and stretching said portion of said elongated webbing pulled out of said housing to arrest the downward movement of said connecting means.
pulling a portion of said elongated webbing out of said housing; and stretching said portion of said elongated webbing pulled out of said housing to arrest the downward movement of said connecting means.
22. A fall arrester as in claim 1 and further comprising:
attachment means for attaching said housing to the harness of a worker.
attachment means for attaching said housing to the harness of a worker.
23. A fall arrester as in claim 22 wherein said attachment means comprises:
a D-ring attached to said harness;
a nozzle secured to said front and rear cover plate;
a portion of said nozzle extending through said D-ring; and locking means on said nozzle for permitting movement of said D-ring over said portion of said nozzle but preventing removal of said D-ring after said D-ring has passed over said portion of said nozzle.
a D-ring attached to said harness;
a nozzle secured to said front and rear cover plate;
a portion of said nozzle extending through said D-ring; and locking means on said nozzle for permitting movement of said D-ring over said portion of said nozzle but preventing removal of said D-ring after said D-ring has passed over said portion of said nozzle.
24. A fall arrester as in claim 23 and further comprising:
abutment means secured on another portion of said nozzle for preventing movement of said D-ring over said another portion.
abutment means secured on another portion of said nozzle for preventing movement of said D-ring over said another portion.
25. A fall arrester as in claim 24 and further comprising:
additional abutment means for preventing pivotal movement of said D-ring when a force is applied to said D-ring.
additional abutment means for preventing pivotal movement of said D-ring when a force is applied to said D-ring.
26. A fall arrester as in claim 23 and further comprising:
resilient means for urging portions of said D-ring into contact with said locking means.
resilient means for urging portions of said D-ring into contact with said locking means.
27. A fall arrester as in claim 26 and further comprising:
a sleeve member mounted for sliding movement over said portion of said nozzle between a location for holding said locking means in a retracted position and a location for permitting movement of said locking means to a locking position.
a sleeve member mounted for sliding movement over said portion of said nozzle between a location for holding said locking means in a retracted position and a location for permitting movement of said locking means to a locking position.
28. Attachment means for attaching a fall arrester to a safety harness comprising:
a fall arrester having front and rear cover plates;
a D-ring attached to said harness;
a nozzle secured between said front and rear cover plates;
a portion of said nozzle extending through said D-ring;
locking means on said nozzle for permitting movement of said D-ring over said portion of said nozzle but preventing removal of said D-ring after said D-ring has passed over said portion of said nozzle.
a fall arrester having front and rear cover plates;
a D-ring attached to said harness;
a nozzle secured between said front and rear cover plates;
a portion of said nozzle extending through said D-ring;
locking means on said nozzle for permitting movement of said D-ring over said portion of said nozzle but preventing removal of said D-ring after said D-ring has passed over said portion of said nozzle.
29. Attachment means as in claim 28 and further comprising:
abutment means secured on another portion of said nozzle for preventing movement of said D-ring over said another portion.
abutment means secured on another portion of said nozzle for preventing movement of said D-ring over said another portion.
30. Attachment means as in claim 28 and further comprising:
resilient means for urging portions of said D-ring into contact with said locking means.
resilient means for urging portions of said D-ring into contact with said locking means.
31. Attachment means as in claim 30 and further comprising:
a sleeve member mounted for sliding movement over said portion of said nozzle between a location for holding said locking means in a retracted position and a location for permitting movement of said locking means to a locking position.
a sleeve member mounted for sliding movement over said portion of said nozzle between a location for holding said locking means in a retracted position and a location for permitting movement of said locking means to a locking position.
32
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US26146094A | 1994-06-17 | 1994-06-17 | |
| US261,460 | 1994-06-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2152025A1 true CA2152025A1 (en) | 1995-12-18 |
Family
ID=22993405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2152025 Abandoned CA2152025A1 (en) | 1994-06-17 | 1995-06-16 | Device and method for arresting a fall |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0687482A3 (en) |
| CA (1) | CA2152025A1 (en) |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2791077B1 (en) * | 1999-12-17 | 2008-02-22 | P M T L | WORKING PLATFORM IN HEIGHT |
| EP1034813B1 (en) * | 1999-03-10 | 2004-11-24 | P.M.T.L. Sas | Safety rail |
| FR2790672B1 (en) * | 1999-03-10 | 2001-06-08 | P M T L | SAFETY DEVICE FOR WORKING AT HEIGHT AND WORKING PLATFORM AT HEIGHT EQUIPPED WITH SAME |
| GB2432140A (en) * | 2005-11-15 | 2007-05-16 | Latchways Plc | Fall arrest safety device |
| GB201518027D0 (en) * | 2015-10-12 | 2015-11-25 | Swisslogo Ag | Self-braking pulley |
| JP2019076372A (en) * | 2017-10-24 | 2019-05-23 | サンコー株式会社 | Safety belt strap winding device |
| TWI668031B (en) * | 2018-09-11 | 2019-08-11 | 振鋒企業股份有限公司 | Fall arrester |
| US20220305308A1 (en) * | 2021-03-26 | 2022-09-29 | Msa Technology, Llc | Two-Part Locking Polymer Hub for Cable Self-Retracting Device |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2546202A (en) * | 1938-04-02 | 1951-03-27 | Trouin Joseph | Apparatus for protection against falls into space |
| GB851981A (en) * | 1958-01-22 | 1960-10-19 | Sala Maskinfabriks Aktiebolag | Improvements in safety blocks |
| FR1270109A (en) * | 1960-07-15 | 1961-08-25 | Fall protection device | |
| GB999552A (en) * | 1962-03-30 | 1965-07-28 | Joseph Trouin | Safety apparatus |
| GB1552667A (en) * | 1977-10-07 | 1979-09-19 | Barrow Hepburn Equip Ltd | Self winding drum |
| DE8511916U1 (en) | 1985-04-22 | 1985-05-30 | Gebr. Wahlefeld GmbH & Co KG, 4150 Krefeld | Full body harness |
| FR2631615B1 (en) * | 1988-05-20 | 1991-07-12 | Froment Sa | BELT WINDER WITH ANTI-TILT SYSTEM |
| US4877110A (en) * | 1988-10-14 | 1989-10-31 | D B Industries, Inc. | Safety device with retractable lifeline |
-
1995
- 1995-06-16 CA CA 2152025 patent/CA2152025A1/en not_active Abandoned
- 1995-06-19 EP EP95109474A patent/EP0687482A3/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| EP0687482A2 (en) | 1995-12-20 |
| EP0687482A3 (en) | 1996-07-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |