CA2080715A1 - Suspended work platform with safety line - Google Patents
Suspended work platform with safety lineInfo
- Publication number
- CA2080715A1 CA2080715A1 CA 2080715 CA2080715A CA2080715A1 CA 2080715 A1 CA2080715 A1 CA 2080715A1 CA 2080715 CA2080715 CA 2080715 CA 2080715 A CA2080715 A CA 2080715A CA 2080715 A1 CA2080715 A1 CA 2080715A1
- Authority
- CA
- Canada
- Prior art keywords
- safety line
- floor
- work platform
- platform
- suspension member
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C15/00—Safety gear
- B66C15/02—Safety gear for retaining load-engaging elements in the event of rope or cable breakage
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Jib Cranes (AREA)
Abstract
ABSTRACT
A suspended work platform is disclosed for use with mobile cranes or other lifting devices. A safety line passes through an automatic locking device to prevent the platform from falling should the main crane lifting cable fail. The platform has a floor and a central, upright tube terminating in a spring loaded, telescopic suspension member. The automatic locking device is attached to the tube, with the safety line slidably retained therein. A linkage is coupled between the suspension member and the locking device to release the locking device upon lifting tension being applied to the suspension member by the crane lifting cable. A reel is mounted under the platform floor to take up the safety line as the platform is being raised, and a spring motor biases the reel to maintain tension in the safety line. The locking device clamps onto the safety line preventing the platform from falling in the absence of lifting tension on the suspension member.
A suspended work platform is disclosed for use with mobile cranes or other lifting devices. A safety line passes through an automatic locking device to prevent the platform from falling should the main crane lifting cable fail. The platform has a floor and a central, upright tube terminating in a spring loaded, telescopic suspension member. The automatic locking device is attached to the tube, with the safety line slidably retained therein. A linkage is coupled between the suspension member and the locking device to release the locking device upon lifting tension being applied to the suspension member by the crane lifting cable. A reel is mounted under the platform floor to take up the safety line as the platform is being raised, and a spring motor biases the reel to maintain tension in the safety line. The locking device clamps onto the safety line preventing the platform from falling in the absence of lifting tension on the suspension member.
Description
2~807~
The present invention relates to suspended scaffolds or work platforms, and in particular, to a suspended platform for use with a mobile crane for bungee (bungie) jumping.
Suspended platforms or scaffolds are used for many purposes, such as in construction, the mining industry, building maintenance and window washing, etc. Most of these platforms are suspended from wire ropes or cables that are wound onto a capstan or windlass to retract or advance the cable, thus raising or lowering the platform.
For safety reasons, it is often desirable and often required by regulatory authorities, that some sort of safety line be provided for people working on these platforms. One end of the safety line usually has to be attached to a fixed object located above the highest point to which the platform will be raised, and the other end of the line usually passes beside the platform and goes down to the ground. Some type of clamping mechanism is mounted on the safety line and is attached to the person working on the platform or to the platform itself so that if the main lifting cable that suspends the platform breaks or loses tensio~, the clamping mechanism clamped onto the safety line prevents the person or platform from falling.
A difficulty with this type of safety line system in the past is that the clamping mechanism must be disengaged and re-engaged each time the platform is raised or lowered. While the clamping mechanism is disengaged, of course, there is no safety backup line available. Another difficulty is that the safety line often gets tangled up or twisted with the main platform lifting cable, especially if the safety line clamping mechanism is attached 2~8071~
rectly to the person working on the platform. Another very serious drawback with this type of safety line system is that the person could get caught or trapped in the falling platform and be attached to the safety line resulting in serious, if not fatal injury to the person.
The suspended platform of the present invention is particularly useful for the sport of bungee jumping. In this application, one end of a bungee cord is attached to the platform and the other end of the cord is attached to a person who jumps off the raised platform. In this application, safety lines as described above would be totally unsuitable, because the bungee cord would become tangled in the safety line resulting in serious injury to the person jumping.
The present invention provides for an automatic safety line that prevents a platform from falling, leaves a clear space below the platform, and avoids the safety line being tangled with the platform or the main cable lifting the platform.
According to the invention, there is provided a suspended work platform for attachment to an overhead lifting device, such as a crane, the work platform comprising a floor, a suspension member located above the floor for releasable connection to the lifting device, and an attachment means connected between the suspension member and the floor for supporting the floor in horizontal position. A safety line is connected to the work platform and is adapted to be connected to a stationary object located at a point above the highest point to which the platform will be raised. A locking member is slidably mounted on the safety line and is attached to a connection on one of the 2~8071~
platform and the stationary object, the locking member having releasable gripping means for clamping onto the safety line. Take up means is coupled to the safety line between the locking member and said connection for shortening and lengthening the safety S line as the platform is raised and lowered relative to the stationary object. Also, an actuator is operably coupled to the locking member and sensitive to a lifting force on the suspension member for causing the gripping means to clamp onto the safety line upon discontinuous of the lifting force on the suspension member.
Preferred embodiments of the invention will now be described, with reference to the accompanying drawings, in which:
Figure 1 is an elevational view of one embodiment of a suspended work platform according to the present invention;
Figure 2 is an enlarged plan view taken along lines 2-2 of Figure 1;
Figure 3 is an enlarged bottom view looking up taken along lines 3-3 of Figure 1;
Figure 4 i6 an enlarged elevational view of a portion of the suspended platform indicated by chain-dotted circle 4 in Figure l;
Figure 5 is an elevational view taken in the direction of arrow 5 in Figure 4 showing the platform suspension member;
Figure 6 is an elevational view similar to Figure 4, partly broken away, illustrating the operation of the locking member;
and Figure 7 is an elevational view similar to Figure 1 but showing another embodiment of a suspended work platform according 208~715 ~o the present invention.
Referring to the drawings, a suspended work platform according to the present invention is generally indicated in Figure 1 by reference numeral 10. Platform 10 is suspended from a cable 12 having the usual hook 14 and weight ball 16 as commonly employed in mobile cranes. A wire rope pennant 18 having loops on each end is coupled between hook 14 and D-shackle or clevis 20. Pin 22 of clevis 20 passes through a hole 24 (see Figure 5) in a suspension member 26, as will be described further below. Neither cable 12, pennant 18 nor clevis 20 is considered to be part of the present invention, so will not be described in further detail. It will be appreciated that hook 14 could be attached directly to suspension member 26 by passing hook 14 through holé 24. Also, any other type of lifting device could be attached to suspension member 26 to raise and lower platform 10, as desired.
A safety line 30 in the form of a wire rope or cable is connected to platform 10 and has an upper end connected to a stationary object (not shown) located at a point above the highest point to which platform 10 is desired to be raised. For example, this stationary object could be the boom of a mobile crane, or if platform 10 is suspended over a side of a building, the stationary object could be the roof of the building.
Referring in particular to Figures 1 to 3, platform 10 includes a hexagonal base 32 having a floor 34 formed of an expanded metal surface supported by a tubular frame 36. A
peripheral skirt 38 extends downwardly and outwardly from floor 34, skirt 38 having one open side 40. Three equi-spaced feet 42 2~715 are provided along the bottom peripheral edge of skirt 38, so that when platform lO is placed on uneven ground, platform lO
will not rock or tip. It will be appreciated that feet 42 can be placed at any location around the periphery of skirt 38.
5A rigid, central tube 44 is attached at its bottom end to floor 34 and extends upwardly to an upper end portion 46 in which suspension member 26 is telescopically mounted, as will be described further below. Tube 44 forms attachment means for supporting the floor in a horizontal position when platform 10 10is suspended by cable 12.
Floor 34 is formed with a pair of openings 48 located adjacent to tube 44, and a tubular retaining member 50 is spaced above floor openings 48. Retaining member 50 is intended for the attachment of elongate, flexible members, such as bungee cords, 15suspended therefrom passing through openings 48. However, other ropes or cables, electrical wires, etc. could be directed through openings 48 into platform 10 as desired.
A tubular cage 52 is attached to floor 34 and extends upwardly and inwardly to upper end portion 46 to form an 20enclosure for platform 10. Cage 52 includes a peripheral, upright, integral railing 54 formed around the periphery of floor 34. In Figure 7, cage 52 includes only the railing 54. A pair of hingeably mounted gates 56 is located in railing 54 adjacent to the open side 40 of skirt 38. Gates 56 are held in the closed 25position by a releasable latch 58. Optional lockers 60 and seats 62 are provided for the storage of tools and equipment, the seats being hinged to swing up for access to the lockers. A toeboard 64 is provided around the lower periphery of railing 54. An 2~8~71~
upper, tubular retaining member 66 is attached to central tube 44. Retaining member 66 is for the attachment of personal safety harnesses for the people working on platform 10.
Referring next to Figures 4 to 6, it will be seen that safety line 30 passes through a locking member 70 and through a lower tube 72 to be directed through an opening in the wall of tube 44 to pass downwardly through the inside of tube 44. At the lower end of tube 44, floor 34 has an opening communicating with the interior of central tube 44 to allow safety line 32 to pass through floor 34 as described further below. Locking member 70 is mounted so that safety line 30 is spaced radially from tube 44 to clear lifting cable 12 as seen best in Figures l and 7.
Locking member 70 includes internal releasable gripping means (not shown) for clamping onto safety line 30. A lever 74, when in the position shown in Figure 6, releases the gripping means, so that the locking member is slidably mounted on safety line 30, or in other words, safety line 30 is free to pass through locking member 70. When lever 74 is in the position shown in Figure 4, the locking means firmly clamps onto safety line 30 to prevent locking member 70 and thus platform 10 from moving relative to safety line 30. The specific construction of locking member 70 is not considered to be part of the present invention and is described further in United States patent No. 3,021,918. Any suitable locking member 70 could be employed in the present invention.
Locking member 70 is operated by an actuator coupled thereto and is sensitive to a lifting force being applied to suspension member 26. This actuator includes a linkage 76 attached to a transverse bar 78 in turn attached to suspension member 26. When suspension member 26 moves up and down inside upper end portion 46, linkage 76 moves lever 74 as shown in Figures 4 and 6.
Suspension member 26 has a central opening 80 and upper end portion 46 has a corresponding slot 82. A key 84 passes through slot 82 and opening 80 to prevent suspension member 26 from rotating relative to tube 44. Upper end portion 46 includes a cap 86 to limit the upward movement of key 84 in slot 82. A spring 88 compressed between the underside of cap 86 and a stop 90 attached to the lower end of suspension member 26 biases suspension member 26 down into tube 44 in a non-extended position. When a lifting force is not being applied to suspension member 26 as indicated by relaxed pennant 18' in Figure 4, bar 78 is in its lowermost position causing the gripping means inside locking member 70 to clamp the safety line 30. When lifting force is again applied to suspension member 26 as indicated in Figure 6, bar 78 is in its uppermost position causing lever 74 to rotate to the position shown in Figure 6 again allowing platform 10 to move freely up or down relative to safety line 30.
Referring again to Figures 1 and 3, the lower end of safety line 30 is attached to plaform 10 and is stored beneath floor 34 and above the lower peripheral edge of skirt 38 by a take-up means including a capstan or reel 90 driven by a spring motor 92.
Safety line 30 exists from the lower end of central tube 44, passes through floor 34, and is turned around a pulley or sheave 94 to be wound onto or wound off reel 90 as platform 10 risea or descends. In this way, safety line 30 is shortened or lengthened as the platform is raised or lowered relative to the stationary 2~807~
object to which the upper end of safety line 30 is attached. It will be appreciated that reel 90 is large enough to store all of the safety line 30 necessary to move platform 10 from the ground to the highest point to which it is desired to be lifted.
Having described preferred embodiments of the invention, it will be appreciated that various modifications may be made to the structures described. For example, in place of the cage 52 having its upper and inwardly directed radial tubular members supporting upper end portion 46, radially extended cables or wire ropes could be used as the attachment means. In fact, central tube 44 could be eliminated. Safety line 30 could then pass straight down through the floor to be wound onto reel 90. Means other than the spring biased telescopic suspension member could be used to actuate locking member 70. Any device activated by tension in lifting cable 12 could be used to activate or release locking member 70. Lever 74 could be linked directly to hook 14 or pennant 18.
Platform 10 can be made any size or shape desired. It will be appreciated that safety line 30 must be sized to handle the load of platform 10 with a suitable safety factor. For a platform with a width or diameter of about 2 meters and a height of about 5 meters, a wire rope safety line with a 14,000 kilogram breaking strength normally would be adequate.
If desired, the reel and spring motor could be mounted at the upper end of the safety line such as on the boom of a crane, to take up the slack in the safety line as the platform is raised.
In this case, the locking member or device would be attached or connected to the boom of the crane as well. The safety line would 2~8071~
,, come off the reel and pass through the locking member and then go down to be attached to the platform. The locking member mu6t be attached to a fixed connection on one of the platform or the stationary object, such as the boom of the crane. The reel and spring motor take-up means is thus mounted on the ~afety line between the locking member and the fixed connection. In this way, when the main lifting cable fails, the locking member prevents the safety line from being unwound from the reel and prevents the platform from falling. When the reel and the locking member are attached to a stationary object above the platform, some other mechanism sen6itive to the lifting force on the main cable must be provided to actuate the locking member when the main lifting cable fails. A horizontal cable with a spring loaded block or pulley coupled between the main lifting cable and the locking member actuator lever would suffice for this purpose.
From the above, it will be appreciated that the suspended work platform of the present invention is a very efficient device with an automatic safety line that is uncluttered and leaves the space below the platform free and clear.
While the present invention has been described and illustrated with respect to preferred and alternative ; embodiments, it will be appreciated that numerous variations ofthese embodiments may be made without departing from the scope of the invention, which is defined in the appended claims.
The present invention relates to suspended scaffolds or work platforms, and in particular, to a suspended platform for use with a mobile crane for bungee (bungie) jumping.
Suspended platforms or scaffolds are used for many purposes, such as in construction, the mining industry, building maintenance and window washing, etc. Most of these platforms are suspended from wire ropes or cables that are wound onto a capstan or windlass to retract or advance the cable, thus raising or lowering the platform.
For safety reasons, it is often desirable and often required by regulatory authorities, that some sort of safety line be provided for people working on these platforms. One end of the safety line usually has to be attached to a fixed object located above the highest point to which the platform will be raised, and the other end of the line usually passes beside the platform and goes down to the ground. Some type of clamping mechanism is mounted on the safety line and is attached to the person working on the platform or to the platform itself so that if the main lifting cable that suspends the platform breaks or loses tensio~, the clamping mechanism clamped onto the safety line prevents the person or platform from falling.
A difficulty with this type of safety line system in the past is that the clamping mechanism must be disengaged and re-engaged each time the platform is raised or lowered. While the clamping mechanism is disengaged, of course, there is no safety backup line available. Another difficulty is that the safety line often gets tangled up or twisted with the main platform lifting cable, especially if the safety line clamping mechanism is attached 2~8071~
rectly to the person working on the platform. Another very serious drawback with this type of safety line system is that the person could get caught or trapped in the falling platform and be attached to the safety line resulting in serious, if not fatal injury to the person.
The suspended platform of the present invention is particularly useful for the sport of bungee jumping. In this application, one end of a bungee cord is attached to the platform and the other end of the cord is attached to a person who jumps off the raised platform. In this application, safety lines as described above would be totally unsuitable, because the bungee cord would become tangled in the safety line resulting in serious injury to the person jumping.
The present invention provides for an automatic safety line that prevents a platform from falling, leaves a clear space below the platform, and avoids the safety line being tangled with the platform or the main cable lifting the platform.
According to the invention, there is provided a suspended work platform for attachment to an overhead lifting device, such as a crane, the work platform comprising a floor, a suspension member located above the floor for releasable connection to the lifting device, and an attachment means connected between the suspension member and the floor for supporting the floor in horizontal position. A safety line is connected to the work platform and is adapted to be connected to a stationary object located at a point above the highest point to which the platform will be raised. A locking member is slidably mounted on the safety line and is attached to a connection on one of the 2~8071~
platform and the stationary object, the locking member having releasable gripping means for clamping onto the safety line. Take up means is coupled to the safety line between the locking member and said connection for shortening and lengthening the safety S line as the platform is raised and lowered relative to the stationary object. Also, an actuator is operably coupled to the locking member and sensitive to a lifting force on the suspension member for causing the gripping means to clamp onto the safety line upon discontinuous of the lifting force on the suspension member.
Preferred embodiments of the invention will now be described, with reference to the accompanying drawings, in which:
Figure 1 is an elevational view of one embodiment of a suspended work platform according to the present invention;
Figure 2 is an enlarged plan view taken along lines 2-2 of Figure 1;
Figure 3 is an enlarged bottom view looking up taken along lines 3-3 of Figure 1;
Figure 4 i6 an enlarged elevational view of a portion of the suspended platform indicated by chain-dotted circle 4 in Figure l;
Figure 5 is an elevational view taken in the direction of arrow 5 in Figure 4 showing the platform suspension member;
Figure 6 is an elevational view similar to Figure 4, partly broken away, illustrating the operation of the locking member;
and Figure 7 is an elevational view similar to Figure 1 but showing another embodiment of a suspended work platform according 208~715 ~o the present invention.
Referring to the drawings, a suspended work platform according to the present invention is generally indicated in Figure 1 by reference numeral 10. Platform 10 is suspended from a cable 12 having the usual hook 14 and weight ball 16 as commonly employed in mobile cranes. A wire rope pennant 18 having loops on each end is coupled between hook 14 and D-shackle or clevis 20. Pin 22 of clevis 20 passes through a hole 24 (see Figure 5) in a suspension member 26, as will be described further below. Neither cable 12, pennant 18 nor clevis 20 is considered to be part of the present invention, so will not be described in further detail. It will be appreciated that hook 14 could be attached directly to suspension member 26 by passing hook 14 through holé 24. Also, any other type of lifting device could be attached to suspension member 26 to raise and lower platform 10, as desired.
A safety line 30 in the form of a wire rope or cable is connected to platform 10 and has an upper end connected to a stationary object (not shown) located at a point above the highest point to which platform 10 is desired to be raised. For example, this stationary object could be the boom of a mobile crane, or if platform 10 is suspended over a side of a building, the stationary object could be the roof of the building.
Referring in particular to Figures 1 to 3, platform 10 includes a hexagonal base 32 having a floor 34 formed of an expanded metal surface supported by a tubular frame 36. A
peripheral skirt 38 extends downwardly and outwardly from floor 34, skirt 38 having one open side 40. Three equi-spaced feet 42 2~715 are provided along the bottom peripheral edge of skirt 38, so that when platform lO is placed on uneven ground, platform lO
will not rock or tip. It will be appreciated that feet 42 can be placed at any location around the periphery of skirt 38.
5A rigid, central tube 44 is attached at its bottom end to floor 34 and extends upwardly to an upper end portion 46 in which suspension member 26 is telescopically mounted, as will be described further below. Tube 44 forms attachment means for supporting the floor in a horizontal position when platform 10 10is suspended by cable 12.
Floor 34 is formed with a pair of openings 48 located adjacent to tube 44, and a tubular retaining member 50 is spaced above floor openings 48. Retaining member 50 is intended for the attachment of elongate, flexible members, such as bungee cords, 15suspended therefrom passing through openings 48. However, other ropes or cables, electrical wires, etc. could be directed through openings 48 into platform 10 as desired.
A tubular cage 52 is attached to floor 34 and extends upwardly and inwardly to upper end portion 46 to form an 20enclosure for platform 10. Cage 52 includes a peripheral, upright, integral railing 54 formed around the periphery of floor 34. In Figure 7, cage 52 includes only the railing 54. A pair of hingeably mounted gates 56 is located in railing 54 adjacent to the open side 40 of skirt 38. Gates 56 are held in the closed 25position by a releasable latch 58. Optional lockers 60 and seats 62 are provided for the storage of tools and equipment, the seats being hinged to swing up for access to the lockers. A toeboard 64 is provided around the lower periphery of railing 54. An 2~8~71~
upper, tubular retaining member 66 is attached to central tube 44. Retaining member 66 is for the attachment of personal safety harnesses for the people working on platform 10.
Referring next to Figures 4 to 6, it will be seen that safety line 30 passes through a locking member 70 and through a lower tube 72 to be directed through an opening in the wall of tube 44 to pass downwardly through the inside of tube 44. At the lower end of tube 44, floor 34 has an opening communicating with the interior of central tube 44 to allow safety line 32 to pass through floor 34 as described further below. Locking member 70 is mounted so that safety line 30 is spaced radially from tube 44 to clear lifting cable 12 as seen best in Figures l and 7.
Locking member 70 includes internal releasable gripping means (not shown) for clamping onto safety line 30. A lever 74, when in the position shown in Figure 6, releases the gripping means, so that the locking member is slidably mounted on safety line 30, or in other words, safety line 30 is free to pass through locking member 70. When lever 74 is in the position shown in Figure 4, the locking means firmly clamps onto safety line 30 to prevent locking member 70 and thus platform 10 from moving relative to safety line 30. The specific construction of locking member 70 is not considered to be part of the present invention and is described further in United States patent No. 3,021,918. Any suitable locking member 70 could be employed in the present invention.
Locking member 70 is operated by an actuator coupled thereto and is sensitive to a lifting force being applied to suspension member 26. This actuator includes a linkage 76 attached to a transverse bar 78 in turn attached to suspension member 26. When suspension member 26 moves up and down inside upper end portion 46, linkage 76 moves lever 74 as shown in Figures 4 and 6.
Suspension member 26 has a central opening 80 and upper end portion 46 has a corresponding slot 82. A key 84 passes through slot 82 and opening 80 to prevent suspension member 26 from rotating relative to tube 44. Upper end portion 46 includes a cap 86 to limit the upward movement of key 84 in slot 82. A spring 88 compressed between the underside of cap 86 and a stop 90 attached to the lower end of suspension member 26 biases suspension member 26 down into tube 44 in a non-extended position. When a lifting force is not being applied to suspension member 26 as indicated by relaxed pennant 18' in Figure 4, bar 78 is in its lowermost position causing the gripping means inside locking member 70 to clamp the safety line 30. When lifting force is again applied to suspension member 26 as indicated in Figure 6, bar 78 is in its uppermost position causing lever 74 to rotate to the position shown in Figure 6 again allowing platform 10 to move freely up or down relative to safety line 30.
Referring again to Figures 1 and 3, the lower end of safety line 30 is attached to plaform 10 and is stored beneath floor 34 and above the lower peripheral edge of skirt 38 by a take-up means including a capstan or reel 90 driven by a spring motor 92.
Safety line 30 exists from the lower end of central tube 44, passes through floor 34, and is turned around a pulley or sheave 94 to be wound onto or wound off reel 90 as platform 10 risea or descends. In this way, safety line 30 is shortened or lengthened as the platform is raised or lowered relative to the stationary 2~807~
object to which the upper end of safety line 30 is attached. It will be appreciated that reel 90 is large enough to store all of the safety line 30 necessary to move platform 10 from the ground to the highest point to which it is desired to be lifted.
Having described preferred embodiments of the invention, it will be appreciated that various modifications may be made to the structures described. For example, in place of the cage 52 having its upper and inwardly directed radial tubular members supporting upper end portion 46, radially extended cables or wire ropes could be used as the attachment means. In fact, central tube 44 could be eliminated. Safety line 30 could then pass straight down through the floor to be wound onto reel 90. Means other than the spring biased telescopic suspension member could be used to actuate locking member 70. Any device activated by tension in lifting cable 12 could be used to activate or release locking member 70. Lever 74 could be linked directly to hook 14 or pennant 18.
Platform 10 can be made any size or shape desired. It will be appreciated that safety line 30 must be sized to handle the load of platform 10 with a suitable safety factor. For a platform with a width or diameter of about 2 meters and a height of about 5 meters, a wire rope safety line with a 14,000 kilogram breaking strength normally would be adequate.
If desired, the reel and spring motor could be mounted at the upper end of the safety line such as on the boom of a crane, to take up the slack in the safety line as the platform is raised.
In this case, the locking member or device would be attached or connected to the boom of the crane as well. The safety line would 2~8071~
,, come off the reel and pass through the locking member and then go down to be attached to the platform. The locking member mu6t be attached to a fixed connection on one of the platform or the stationary object, such as the boom of the crane. The reel and spring motor take-up means is thus mounted on the ~afety line between the locking member and the fixed connection. In this way, when the main lifting cable fails, the locking member prevents the safety line from being unwound from the reel and prevents the platform from falling. When the reel and the locking member are attached to a stationary object above the platform, some other mechanism sen6itive to the lifting force on the main cable must be provided to actuate the locking member when the main lifting cable fails. A horizontal cable with a spring loaded block or pulley coupled between the main lifting cable and the locking member actuator lever would suffice for this purpose.
From the above, it will be appreciated that the suspended work platform of the present invention is a very efficient device with an automatic safety line that is uncluttered and leaves the space below the platform free and clear.
While the present invention has been described and illustrated with respect to preferred and alternative ; embodiments, it will be appreciated that numerous variations ofthese embodiments may be made without departing from the scope of the invention, which is defined in the appended claims.
Claims (18)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A suspended work platform for attachment to an overhead lifting device, such as a crane, the work platform comprising:
a floor;
a suspension member located above the floor for releasable connection to the lifting device;
attachment means connected between the suspension member and the floor for supporting the floor in a horizontal position;
a safety line connected to the work platform and adapted to be connected to a stationary object located at a point above the highest point to which the platform will be raised;
a locking member slidably mounted on the safety line and attached to a connection on one of the platform and the stationary object, the locking member having releasable gripping means for clamping onto the safety line;
take-up means coupled to the safety line between the locking member and said connection for shortening and lengthening the safety line as the platform is raised and lowered relative to the stationary object; and an actuator operably coupled to the locking member and sensitive to a lifting force on the suspension member for causing the gripping means to clamp onto the safety line upon discontinuance of a lifting force on the suspension member.
a floor;
a suspension member located above the floor for releasable connection to the lifting device;
attachment means connected between the suspension member and the floor for supporting the floor in a horizontal position;
a safety line connected to the work platform and adapted to be connected to a stationary object located at a point above the highest point to which the platform will be raised;
a locking member slidably mounted on the safety line and attached to a connection on one of the platform and the stationary object, the locking member having releasable gripping means for clamping onto the safety line;
take-up means coupled to the safety line between the locking member and said connection for shortening and lengthening the safety line as the platform is raised and lowered relative to the stationary object; and an actuator operably coupled to the locking member and sensitive to a lifting force on the suspension member for causing the gripping means to clamp onto the safety line upon discontinuance of a lifting force on the suspension member.
2. A suspended work platform as claimed in claim 1 wherein the attachment means includes an upper end portion centrally located above the floor and means for retaining the upper end portion in position relative to the floor.
?. A suspended work platform as claimed in claim 2 wherein the locking member is attached to the upper end portion.
4. A suspended work platform as claimed in claim 3 wherein the suspension member is telescopically mounted on the upper end portion to extend upon being lifted by the lifting device, and wherein the actuator includes a linkage connected between the suspension member and the locking member for releasing the gripping means upon extension of the suspension member.
5. A suspended work platform as claimed in claim 4 wherein the suspension member is biased into a non-extended position, so that the gripping means is clamped onto the safety line when the suspension member is not being lifted.
6. A suspended work platform as claimed in claim 2 wherein the means for retaining the upper end portion in position includes a plurality of radially extending members connected between the upper end portion and the floor.
7. A suspended work platform as claimed in claim 2 wherein the attachment means is a rigid, central tube attached to the floor, the upper end portion being the upper end portion of said tube.
8. A suspended work platform as claimed in claim 7 wherein the locking member is attached to the upper end portion, so that the safety line is spaced from the lifting device.
9. A suspended work platform as claimed in claim 8 wherein the suspension member is telescopically mounted on the upper end portion to extend upon being lifted by the lifting device, and wherein the actuator includes a linkage connected between the suspension member and the locking member for releasing the gripping means upon extension of the suspension member.
10. A suspended work platform as claimed in claim 9 wherein the suspension member is biased into a non-extended position, so that the gripping means is clamped onto the safety line when the suspension member is not being lifted.
11. A suspended work platform as claimed in claim 8 wherein the floor is formed with an opening in communication with the interior of the central tube, and wherein the central tube is formed with an opening located below the locking member, the safety line passing through said tube opening to exist through said floor opening.
12. A suspended work platform as claimed in claim 11 wherein the take-up means is a reel mounted beneath the floor for winding the safety line thereon, and further comprising a spring motor operably coupled to the reel to wind the safety line thereon.
13. A suspended work platform as claimed in claim 5 wherein the take-up means is a reel mounted beneath the floor for winding the safety line thereon, and further comprising a spring motor operably coupled to the reel to wind the safety line thereon.
14. A suspended work platform as claimed in claim 12 wherein the floor is formed with a peripheral skirt extending below the reel.
15. A suspended work platform as claimed in claim 12 and further comprising a peripheral, upright railing formed around the periphery of the floor.
16. A suspended work platform as claimed in claim 7 wherein the floor is formed with an opening adjacent to the tube, and further comprising a retaining member spaced above the floor opening for suspending elongate, flexible members passing through said floor opening.
17. A suspended work platform as claimed in claim 1 wherein the locking member is connected to the stationary object.
18. A suspended work platform as claimed in claim 17 wherein the take-up means is a reel mounted on the stationary object, and further comprising a spring motor operably coupled to the reel and to wind the safety line thereon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2080715 CA2080715A1 (en) | 1992-10-16 | 1992-10-16 | Suspended work platform with safety line |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2080715 CA2080715A1 (en) | 1992-10-16 | 1992-10-16 | Suspended work platform with safety line |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2080715A1 true CA2080715A1 (en) | 1994-04-17 |
Family
ID=4150553
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2080715 Abandoned CA2080715A1 (en) | 1992-10-16 | 1992-10-16 | Suspended work platform with safety line |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2080715A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE202012009836U1 (en) * | 2012-10-15 | 2014-01-16 | Liebherr-Werk Ehingen Gmbh | Device for transporting persons by means of a crane - Crane with device for transporting persons |
| CN105858532A (en) * | 2016-06-03 | 2016-08-17 | 国网山东省电力公司栖霞市供电公司 | Adjustable lifting platform used in aerial work for line construction |
| EP3406561A1 (en) * | 2017-05-25 | 2018-11-28 | Jr. James Zaguroli | Safety arrangement for a hoist |
| US10792520B2 (en) | 2014-09-12 | 2020-10-06 | D B Industries, Llc | Personal descent system |
-
1992
- 1992-10-16 CA CA 2080715 patent/CA2080715A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE202012009836U1 (en) * | 2012-10-15 | 2014-01-16 | Liebherr-Werk Ehingen Gmbh | Device for transporting persons by means of a crane - Crane with device for transporting persons |
| EP2719652A1 (en) * | 2012-10-15 | 2014-04-16 | Liebherr-Werk Ehingen GmbH | Device for the transportation of persons by means of a crane, and crane with a device for the transportation of persons |
| US10792520B2 (en) | 2014-09-12 | 2020-10-06 | D B Industries, Llc | Personal descent system |
| CN105858532A (en) * | 2016-06-03 | 2016-08-17 | 国网山东省电力公司栖霞市供电公司 | Adjustable lifting platform used in aerial work for line construction |
| EP3406561A1 (en) * | 2017-05-25 | 2018-11-28 | Jr. James Zaguroli | Safety arrangement for a hoist |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Dead |