JP2020111949A - Safety ladder - Google Patents

Abstract

To provide a safety ladder to which a fall preventive device is attached, preventing the rise of the center of gravity of ladders (including single type, double type, and multiple type ladders).CONSTITUTION: A double type safety ladder A is configured such that: a fall prevention device 4 is fixed to a lower part of a lower ladder with a mounting metal fitting 10; a fixed pulley is hung down by a hanging metal fitting 50 on an upper rung 23 of the uppermost stage; and a wire (w) with a hook (f) is drawn so as to rise behind each lower ladder 13, to rise while coming out to the front of the upper rung 23 at an overlapped part of the ladders, to be hung down behind each ladder after being hung over the fixed pulley 5. Since the fall prevention device 4 is fixed to the lower part of the lower ladder of the double type safety ladder A, its center of gravity is lowered, and wobbling or falling hardly occurs when the double type safety ladder A is leaned against a work object. Further, since the double type safety ladder A does not wobble when a worker climbs up and down the rungs after the double type safety ladder A is leaned against the work object, the worker can be prevented from missing his/her footing.SELECTED DRAWING: Figure 1

Description

INDUSTRIAL APPLICABILITY The present invention is a safety ladder with a safety block that is carried by a work vehicle to the vicinity of a work site where work is performed at a high place, is manually carried to the work site at the work site, and is leaned against the work item at an angle of about 75 degrees for use. Series, including double, triple or more multiple).

Of the ladders, double ladders (also known as movable ladders) are often used when working in high places.

A safety block (also known as a fall arrester) is used to prevent a worker performing work in high places from falling.

Patent Document 1 describes a technique in which a safety block is attached to the upper part of a movable ladder installed along a vertical shaft.

JP2011-256532

If a relatively heavy fall arrester is attached to the top of the ladder, the center of gravity of the ladder rises and the ladder becomes unstable.

In addition, in the case of a ladder fixed to a vertical shaft or the like, there is no need to manually carry it to the vertical shaft or the like, and it is not necessary to lean against the vertical shaft or the like, so there is no problem even if the center of gravity of the ladder rises.

However, in the case of a ladder that leans against a work item at the work site, the following problems occur when carrying the ladder to the work item by hand, when leaning against the work item, or when the worker raises or lowers the step. Occurs.

Since the upper part of the ladder with the fall arrester attached becomes heavy, the upper part of the ladder drops when carrying, making it difficult to carry.

Since the center of gravity of the ladder rises, it is easy for the ladder to stick or fall when leaning against a work piece.

Since the center of gravity of the ladder rises, it is easy for the ladder to grind and the operator can easily step off the leg when going up and down the cross rail after leaning.

An object of the present invention is to provide a safety ladder equipped with a fall preventer, which prevents the center of gravity of a ladder (including a series, a double series, and a multiple series) from rising.

[Claim 1]
The double safety ladder has a lower ladder having a lower step, an upper ladder having an upper step, an expansion and contraction fixing means capable of locking the upper ladder at an arbitrary height, and a hook-shaped cord. It is equipped with a fall arrester and a fixed pulley that can be suspended from the upper step rail.

The lower ladder has left and right lower columns that stand upright at a predetermined interval, and a plurality of lower step bars that are attached to the left and right lower columns at different height positions.

The upper ladder has left and right upper struts which are erected at a predetermined interval, and a plurality of upper pedestals attached to the left and right upper struts at different height positions.

The upper and lower ladders are vertically movable behind the lower ladder and can be locked at an arbitrary height by the expansion and contraction fixing means.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is fixed to the lower portion of the lower ladder (preferably, a place surrounded by the lower step rail and the left and right lower support columns located below the lower step rail) with a mounting bracket.

When using a ladder, the cords with hooks extended from the fall arrester rise behind the lower ladders, rise to the front of the upper step at the overlapped part of the ladder, and are hung on the fixed pulley. It is routed so as to hang down the front of each step.

The fixed pulley is hung on the upper step rail of the uppermost stage with suspension fittings.

The double safety ladder of claim 1 has the following advantages.

A relatively heavy fall arrester is fixed to the bottom of the lower ladder with a mounting bracket. In addition, the fixed pulley is hung on the upper cross rail of the uppermost stage with suspension metal fittings.

Usually, (weight of fall arrester + weight of mounting bracket)> (weight of fixed pulley + weight of suspension bracket), so that the center of gravity of the two safety ladders lowers when the ladder is extended and used.

When the two safety ladders are extended and used, the center of gravity is lowered, so when leaning against a work piece, it is difficult for them to grind or fall.

When extended and used, the center of gravity is lowered, which makes it difficult for the operator to grind and to step off the foot when raising and lowering the step ladder after leaning two safety ladders on the work.

The two safety ladders in the contracted state are (weight of fall arrester + weight of mounting bracket) offset by (weight of fixed pulley + weight of suspending bracket) to some extent, so the lower part of the lower ladder during transportation Is difficult to drop and is easy to carry.

When using a ladder, the cords with hooks extended from the fall arrester rise behind the lower ladders, rise to the front of the upper step at the overlapped part of the ladder, and are hung on the fixed pulley. Since it is routed so as to hang down the front of each step, the cords do not easily interfere when the operator climbs the step.

Since the length of the cord is required to be approximately twice as long as the structure in which the fall arrester is attached to the upper part of the ladder, it is necessary to double the length of the cord wound in the fall arrester. Connect the cords and lengthen them.
[Claim 2]
The double safety ladder has a lower ladder having a lower step, an upper ladder having an upper step, an expansion and contraction fixing means capable of locking the upper ladder at an arbitrary height, and a hook-shaped cord. It is equipped with a fall arrester and a fixed pulley that can be suspended from the upper step rail.

The lower ladder has left and right lower columns that stand upright at a predetermined interval, and a plurality of lower step bars that are attached to the left and right lower columns at different height positions.

The upper ladder has left and right upper struts which are erected at a predetermined interval, and a plurality of upper pedestals attached to the left and right upper struts at different height positions.

The upper and lower ladders are vertically movable behind the lower ladder and can be locked at an arbitrary height by the expansion and contraction fixing means.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is surrounded by the lower part of the upper ladder (preferably, the upper step bar two steps from the bottom, the upper step bar one step above it, and the left and right upper posts located between these upper step bars. Fixed location) with mounting brackets.

When using a ladder, the cord-like body with hooks extended from the fall arrester rises behind each upper step rail, is hung on a fixed pulley, and then is drawn down so as to hang down the front surface of each step rail. There is.

The fixed pulley is hung on the upper step rail of the uppermost stage with suspension fittings.

The double safety ladder of claim 2 has the following advantages.

In the double safety ladder of the second aspect, a relatively heavy fall arrester is fixed to the lower part of the upper ladder by a mounting metal fitting, and the fixed pulley is hung by the suspension metal fitting on the upper step rail of the uppermost stage.

Therefore, when the ladder is extended and used, the center of gravity increases in the case of the conventional ladder in which the fall arrester is attached to the upper part of the ladder, but the center of gravity does not increase in the double safety ladder of claim 2.

When the two safety ladders are used in a stretched state, the center of gravity does not rise so much that when the two safety ladders are leaned against a work piece, it is easy for them to fall or fall.

When the two safety ladders are extended and used, the center of gravity does not rise so much that it is difficult for the workers to grind when raising and lowering the step ladder after leaning the two safety ladders on the work, and it is easy for the operator to step off the foot. ..

When the two safety ladders are folded, the (weight of the fall arrester + weight of the mounting bracket) is offset to some extent by (weight of the fixed pulley + weight of the suspension bracket) in the folded state. The bottom of the ladder is difficult to drop and is easy to carry.

When using a ladder, the cords with hooks that extend from the fall arrester rise behind the upper ladders and are hung around the front of each step rail after being hung on a fixed pulley. Therefore, when the two safety ladders are extended, it is difficult for the cords to interfere with the lower ladder.

In the double safety ladder according to the second aspect of the present invention, since the cord is required to be longer than the structure in which the fall arrester is attached to the upper part of the ladder, the length of the cord wound in the fall arrester is lengthened. Or, connect the cords and lengthen them.

However, the double safety ladder according to claim 2 has a payout length of about 3/4 that of the double safety ladder according to claim 1, and therefore the double safety ladder is wound in the fall arrester. The body length can be about 3/4.
[Claim 3]
The double safety ladder has a lower ladder having a lower step, an upper ladder having an upper step, an expansion and contraction fixing means capable of locking the upper ladder at an arbitrary height, and a hook-shaped cord. It is equipped with a fall arrester and a suspension roller that can be suspended from the upper step rail.

The lower ladder has left and right lower columns that stand upright at a predetermined interval, and a plurality of lower step bars that are attached to the left and right lower columns at different height positions.

The upper ladder has left and right upper struts which are erected at a predetermined interval, and a plurality of upper pedestals attached to the left and right upper struts at different height positions.

The upper and lower ladders are vertically movable behind the lower ladder and can be locked at an arbitrary height by the expansion and contraction fixing means.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is fixed to the lower part of the lower ladder (preferably, a place surrounded by the lower step rail and the left and right lower support columns located below the lower step rail) with a fitting.

When using a ladder, the cords with hooks extended from the fall arrester rise behind the lower ladders, rise to the front of the upper step at the overlapped portion of the ladder, and are hung on the hanging rollers. It is routed so as to hang each rail.

The hanging roller is hung on the upper step rail of the uppermost stage with a hanging metal fitting.

The double safety ladder of claim 3 has the following advantages.

In the double safety ladder according to the third aspect of the invention, a relatively heavy fall arrester is fixed to the lower part of the lower ladder with a mounting bracket, and the suspension roller is hung with a suspending bracket on the upper step rail of the uppermost stage.

Usually, (weight of fall arrester + weight of mounting bracket)> (weight of suspension roller + weight of suspending bracket), so that the double safety ladder according to claim 3 has a center of gravity lowered in a state of being extended and used. ..

Since the center of gravity is lowered when it is extended and used, it is easy to get stuck or fall when leaning two safety ladders on a work.

Since the center of gravity is lowered in a state of being extended and used, it is difficult for the worker to grind when the stairs are raised and lowered after the two safety ladders are leaned against the work piece, and the worker can easily step off the foot.

In the folded state, in the two safety ladders, (weight of fall arrester + weight of mounting bracket) is slightly offset by (weight of suspending roller + weight of suspending bracket). It is difficult to drop and easy to carry.

When using a ladder, the cord with hooks that are fed from the fall arrester rises behind the lower ladder, rises to the front of the upper step at the overlapping part of the ladder, and then is suspended on the hanging roller. Since it is laid down so as to hang down, it is difficult for the cords to interfere when the worker climbs up the step.

Since the length of the cord is required to be approximately twice as long as the structure in which the fall arrester is attached to the upper part of the ladder, it is necessary to double the length of the cord wound in the fall arrester. Connect the cords and lengthen them.

In the hanging roller, since the groove of the sheep is usually V-shaped, the cord-like body is less likely to come off than the fixed pulley.
[Claim 4]
The double safety ladder has a lower ladder having a lower step, an upper ladder having an upper step, an expansion and contraction fixing means capable of locking the upper ladder at an arbitrary height, and a hook-shaped cord. It is equipped with a fall arrester and a hanging wagon that can be suspended from the upper step rail.

The lower ladder has left and right lower columns that stand upright at a predetermined interval, and a plurality of lower step bars that are attached to the left and right lower columns at different height positions.

The upper step bar has left and right upper columns that are erected at a predetermined interval, and a plurality of upper step bars that are attached to the left and right upper columns at different height positions.

The upper and lower ladders are vertically movable behind the lower ladder and can be locked at an arbitrary height by the expansion and contraction fixing means.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is fixed to the lower part of the lower ladder (preferably, a place surrounded by the lower step rail and the left and right lower support columns located below the lower step rail) with a mounting bracket.

The cord with hook that is fed from the fall arrester rises behind each lower ladder, goes out to the front of the upper step at the overlapped part of the ladder, rises, and hangs down after hanging on the suspension wagon. Have been routed to.

The hanging wagon is hung on the upper step rail of the uppermost stage.

The dual safety ladder of claim 4 has the following advantages.

A relatively heavy fall arrester is fixed to the lower part of the lower ladder (preferably, a place surrounded by the lower step rail and the left and right lower support columns located below the lower step rail) with a mounting bracket. In addition, a hanging wagon is hung on the upper cross rail of the top stage.

Usually, (weight of fall arrester + weight of mounting bracket)> weight of suspension car, so the center of gravity is lowered when two safety ladders are extended and used.

In the double safety ladder according to claim 4, the center of gravity of the double safety ladder lowers when it is extended and used. Therefore, when leaning the double safety ladder against a work, it is difficult for the double safety ladder to fall or fall.

Since the center of gravity of the double safety ladder lowers when it is extended and used, the double safety ladder does not easily grind when the stairs are raised or lowered after the double safety ladder is leaned against the work piece, and the operator's foot is less likely to move. It's hard to step on.

In the folded state, in the double safety ladder, (the weight of the fall arrester + the weight of the mounting bracket) is offset to some extent by the weight of the suspension wagon, so the lower part of the lower ladder is difficult to drop when carrying. Easy to carry.

When using a ladder, the cord-like body with hooks extended from the fall arrester rises behind each lower ladder, rises to the front of the upper step at the overlapping part of the ladder, and is hung on the sling car. Since the ladders are laid down so that each ladder hangs down, it is difficult for the cords to interfere with each other when the worker climbs the step.

In the double safety ladder according to claim 4, the length of the cord is required to be approximately twice as long as that of the conventional double ladder in which the fall arrester is attached to the upper part of the ladder. The length of the cord to be wound is approximately doubled, or the cords are connected and lengthened.
[Claim 5]
A series of safety ladders includes a ladder, a fall arrester for feeding out a hooked cord, and a pulley attached to a step rail.

The ladder has left and right columns that are erected at a predetermined interval, and a plurality of cross rails that are attached to the left and right columns at different height positions.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is fixed to the lower part of the ladder (preferably, a place surrounded by the lowest step pedestal and the left and right stanchions located below the step pedestal) with a mounting bracket.

When using a ladder, the cord-like body with hooks extended from the fall arrester rises behind each step of the ladder, is hung on the pulley, and then is drawn down so as to hang down the front of each step. ing.

The pulley-like body is attached to the uppermost step rail.

The series of safety ladders according to claim 5 has the following advantages.

In the series of safety ladders according to the fifth aspect, a relatively heavy fall arrester is fixed to the lower part of the ladder with a mounting bracket. A pulley is attached to the top step rail.

Usually, (weight of fall arrester+mounting bracket)>(weight of pulley), the center of gravity is lowered when a series of safety ladders are used.

In the series of safety ladders according to claim 5, the center of gravity of the ladder is lowered when the ladder is in use, and therefore it is difficult for the ladder to fall or fall when leaning against a work.

In addition, since the center of gravity is lowered, it is difficult for the operator to grind when the ladder is raised and lowered after the series of safety ladders are leaned against the work, and it is difficult for the operator to step off the foot.

A series of safety ladders is (weight of the fall arrester + mounting bracket) offset to some extent by (weight of the pulley), so the lower part of the ladder is difficult to drop during transportation and is easy to carry.

When using a ladder, the cord-like body with hooks extended from the fall arrester rises behind each step of the ladder and is hung around the front of each step after being hung on the pulley. Therefore, the cords do not easily interfere with each other when the worker climbs the crossing.

A series of safety ladders requires approximately twice the length of the cord as compared to the conventional series of ladders that attach the fall arrester to the top of the ladder. Double the length or connect the cords to make them longer.
[Claim 6]
The multiple safety ladder includes a lower ladder having a lower step, an upper ladder having an upper step, one or more middle ladders having an intermediate step, and a fall arrester for feeding the hooked cord. , A pulley attached to the upper step rail.

The lower ladder has left and right lower columns that stand upright at a predetermined interval, and a plurality of lower step bars that are attached to the left and right lower columns at different height positions.

The upper ladder has left and right upper struts which are erected at a predetermined interval, and a plurality of upper pedestals attached to the left and right upper struts at different height positions.

The one or more middle ladders have left and right middle columns that are erected at a predetermined interval, and a plurality of middle pedestals that are attached to the left and right middle columns at different height positions.

By the expansion and contraction fixing means, each ladder except the lower ladder can move up and down and can be locked at any height position.

The fall arrester has a structure that locks when the withdrawal speed of the cord exceeds a limit value. This fall arrester is attached to the lower part of the ladder of one of the ladders (preferably, the lower part of the lower ladder surrounded by the lower step of the lower step and the left and right lower columns below the lower step of the ladder). Fixed.

When using a ladder, the hook-shaped cord extended from the fall arrester is hung around the pulley and then hung around the front of each step rail.

The pulley-shaped body is attached to the upper step rail of the upper ladder.

The multiple safety ladder of claim 6 has the following advantages.

In the multiple safety ladder according to claim 6, a relatively heavy fall arrester is fixed to the lower part of the ladder of any one of the ladders with a mounting bracket, and a pulley-like body is attached to the upper step rail of the upper ladder. ..

When the ladder is extended and used, the center of gravity of the conventional ladder in which the fall arrester is attached to the upper portion of the ladder is significantly increased.

However, in general, (weight of fall arrester+mounting bracket)>(weight of pulley-shaped body), the center of gravity of the multiple ladder according to claim 6 is lowered in the usage state (the ladder of the lower ladder. (If a fall arrester is attached to the bottom), or the center of gravity does not rise much (if a fall arrester is attached to the bottom of the ladder of the upper ladder).

When the multiple safety ladders of claim 6 are extended and used, the center of gravity decreases or the center of gravity does not rise so much that when the multiple safety ladders are leaned against a work object, they fall or fall. Easy to do.

When the multiple safety ladders are extended and used, the center of gravity decreases or the center of gravity does not rise so easily after the multiple safety ladders are leaned against the work piece, it is easy for the ladder to move up and down. , It is easy for the worker to step off.

In the folded safety ladder, (weight of fall arrester + weight of mounting bracket) is offset to some extent by (weight of pulley-like body) in the folded state, so the lower part of the upper ladder is lowered when carrying. Difficult and easy to carry.

When using a ladder, the cord-like body with hooks extended from the fall arrester is laid so that it hangs down on the front of each step after being hung on the pulley, so when extending the multiple ladder, It is difficult for the cord to interfere with the ladder.

In the multiple safety ladder of claim 6, since the cords need to be longer than the structure in which the fall arrester is attached to the upper part of the ladder, the length of the cords wound inside the fall arrester is reduced. Lengthen or connect cords to lengthen.

It is explanatory drawing of the double safety ladder which concerns on Example 1 of this invention. It is explanatory drawing of the fall arrester used for a double safety ladder. It is explanatory drawing of the double safety ladder which concerns on Example 2 of this invention. It is explanatory drawing of the double safety ladder which concerns on Example 3 of this invention. It is explanatory drawing of the double safety ladder which concerns on Example 4 of this invention. It is explanatory drawing of a series of safety ladders concerning Example 5 of this invention. It is explanatory drawing of the triple safety ladder which concerns on Example 6 of this invention.

The double safety ladder consists of a lower ladder having a plurality of lower step bars, an upper ladder having a plurality of upper step bars, a telescopic fixing means capable of locking the upper ladder at an arbitrary height, and a lower part of the lower ladder. It is equipped with a fall arrester that feeds out a fixed hooked cord, and a fixed pulley that is hung on the upper step rail.The cord extended from the fall arrester rises behind each lower ladder and At the overlapping part, it goes out to the front of the upper cross rail, rises, is hung on a fixed pulley, and then is drawn down to hang behind each ladder.

The double safety ladder has a fall arrester fixed to the lower part of the lower ladder, so the center of gravity is lowered, and when leaning the double safety ladder against the work piece, it is difficult for the safety ladder to fall or fall. In addition, it is difficult for the operator to step on the work ladder after the two safety ladders are leaned against the work, and it is difficult for the worker to step off the foot.

A double safety ladder A (corresponding to claim 1) according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the double safety ladder A includes a lower ladder 1 having a plurality of lower step bars 13 attached between the lower left support 11 and the lower right support 12, and a plurality of upper ladders between the upper left support 21 and the upper right support 22. The upper ladder 2 to which the step rail 23 is attached, the expansion and contraction fixing means 3 capable of locking the upper ladder 2 at an arbitrary height, the fall preventer 4 fixed to the lower portion of the lower ladder by the mounting bracket 10, and the upper step rail. 23 is provided with a fixed pulley 5 that is suspended by a suspension fitting 50.

The lower left support 11 and the lower right support 12 are hollow aluminum pipes having a rectangular cross section and a length of several meters. Ends 111 and 112 for slip prevention are attached to the lower ends of the lower left support 11 and the lower right support 12.

The lower left support 11 and the lower right support 12 are arranged side by side at intervals of several tens of cm, and between the lower left support 11 to the lower right support 12, seven lower step bars 13 are attached at equal intervals.

The upper left column 21 and the upper right column 22 are hollow aluminum pipes having a rectangular cross section and a length of several meters.

End caps 211 and 221 for injury prevention are attached to the upper ends of the upper left pillar 21 and the upper right pillar 22, respectively.

The upper left support 21 and the upper right support 22 are arranged side by side with an interval of several tens of cm, and six upper step bars 23 are attached between the upper left support 21 and the upper right support 22.

The expansion/contraction fixing means 3 is composed of brackets 31, 32, stoppers 33, locks, racks, etc., supports the upper ladder 2 movably up and down behind the lower ladder 3, and supports the upper ladder 2 at an arbitrary height. It is a known mechanism that can be locked with.

In addition, when the lower end of the upper ladder 2 is lowered to the lower end of the lower ladder 1, the upper ladder 2 hits the mounting bracket 10, so that the lower end of the upper ladder 2 may be moved when the two safety ladders A are transported or stored. Lower to the second stage of lower ladder 1.

The fall arrester 4 has a structure that locks when the drawing speed of the wire w exceeds a limit value (see FIG. 2). The fall preventer 4 is fixed by a mounting bracket 10 to the lower portion of the lower ladder surrounded by the lower step rail 13 at the bottom and the left and right lower columns 11 and 12 located below the lower step rail 13.

The housing 40 of the fall arrester 4 is formed by connecting a rear housing 41, which is bolted to the mounting bracket 10, and a front housing 42.

The mounting member 10 has a substantially U-shaped cross section, and is bolted to the left and right lower columns 11 and 12 at the lower end of the lower ladder 1.

The shaft 411 of the fall prevention device 4 is fixed to the center of the rear housing 41.

The drum 43 is housed in the rear housing 41 and is loosely fitted on the shaft 411. A wire w with a hook f is wound around the drum 43.

The hook f is for hooking on the metal fitting of the worker's safety belt.

The drum 43 has a spring (not shown) built therein, and is rotated by the urging force of the spring to wind the wire w.

A shaft 44 is fixed to the inner peripheral side of the drum 43, and a shaft 45 is fixed to the outer peripheral side.

A ratchet wheel 46 is fixed to the center of the front housing 42.

A ratchet 47 is rotatably attached to the shaft 44. The base end side of the ratchet 47 is connected to the shaft 45 via a spring 48.

The ratchet 47 is biased in the counterclockwise direction by a spring 48 so as not to be locked by the ratchet wheel 46. In this state, the drum 43 loosely fitted on the shaft 411 can rotate. This state is the case where the worker moves up and down the ladder at a normal speed.

When the operator accidentally steps off one of the steps of the two safety ladders A, the wire w is suddenly pulled out via the constant pulley 5 described later, so that the drum 43 rotates at a high speed and the ratchet 47. Rotates around the shaft 44 against the force of the spring 48 and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, so that the feeding of the wire w is stopped, and the collision of the worker with the ground can be prevented.

The wire w with the hook f fed from the fall arrester 4 rises behind the lower ladder 1 and comes out to the front of the upper step bar 2 at the overlapping portion of the ladder and rises to the sheep 51 of the constant pulley 5 described later. It is laid around after being hung over.

When transporting or storing the two safety ladders A, the wire w fed from the fall arrester 4 is hung on the constant pulley 5 and then slightly hung down so that the hook f is fixed. The upper step bar 23 below is locked.

The fixed pulley 5 includes a disk-shaped sheep 51 having a groove formed around the wire w, and a shaft frame holder 53 with a suspension hole that pivotally supports the sheep 51 with a shaft 52.

The suspension metal fitting 50 includes a top plate 501, suspension pieces 502 and 502 with holes that hang down from the lower surface of the top plate 501, and bolts and nuts 503 for fixing the top plate 501 to the uppermost step rail 23 of the uppermost stage. The fixed pulley 5 is hung on the lower surface of the center of the upper step rail 23 of the uppermost stage, and is made up of a mounting pin 504 fitted into the hole of the hanging piece 502 and the suspension hole of the shaft frame holder 53.

Next, a method of using the double safety ladder A of the first embodiment will be described.
(1) Carry the two safety ladders A in a contracted state to the work site and place them on the ground near the roof of the house (work). Then, the hook f is removed from the step rail (for example, the upper step rail 23), and the wire w is pulled out at a speed not exceeding the limit value to the extent of the dimension of the step rail.

When the two safety ladders A are in a contracted state (during transportation or storage), the wire w fed from the fall arrester 4 faces the back of each lower ladder 13 and is stepped on at the overlapping portion of the ladders. The hook f is brought out to the front of the crosspiece 23 and hung on the sheep 51 of the constant pulley 5, and then the hook f is locked to the step crosspiece (for example, the upper step crosspiece 23).
(2) With the two safety ladders A tilted down, unlock the clasp 33, extend the upper ladder 2 to the maximum length, and place the clasp 33 on the lower step rail 13 of the uppermost stage of the lower ladder 1. Lock and fix the upper ladder 2.
(3) The extended safety ladder A is leaned against the house at an installation angle of 75 degrees. Then, the hook f of the wire w is fitted into the carabiner of the worker's safety belt.
(4) The worker starts climbing the two safety ladders A from the lower ladder 13 of the lower ladder 1, changes to the upper ladder 23 of the upper ladder 2 at the joint, and climbs the two safety ladders A of the house. Reach the roof.

In the unlikely event that the worker steps out of the step of the double safety ladder A, the wire w is suddenly pulled out from the fall arrester 4 via the sheep 51 of the constant pulley 5, so that the drum 43 is driven at high speed. As it rotates, the ratchet 47 rotates about the shaft 44 against the force of the spring 48 and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the collision with the ground is prevented.

The double safety ladder A according to the first embodiment has the following advantages.

In the double safety ladder A, the relatively heavy fall arrester 4 is fixed to the lower portion of the lower ladder by the mounting bracket 10. Then, the fixed pulley 5 is hung on the upper step 23 of the uppermost stage by the suspension metal fitting 50.

As a result, (the weight of the mounting bracket 10+the weight of the fall arrester 4)>(the weight of the constant pulley 5+the weight of the suspension bracket 50), and therefore the fall arrester 4 and the constant pulley 5 are not attached when the ladder is extended and used. The center of gravity of the double safety ladder A is lower than that of the double safety ladder.

Since the center of gravity of the two safety ladders A is lowered when they are extended and used, it is difficult for the two safety ladders A to fall or fall when leaning against a house as a work.

When the two safety ladders A are extended and used, the center of gravity is lowered. Therefore, even after the two safety ladders A are leaned against the house, the operator can move the lower step 13 and the upper step 23 up and down. Difficult to get on and it is difficult for the operator to step off the crossing.

In the double-folded safety ladder A, (the weight of the mounting bracket 10+the fall arrester 4) is offset to some extent by the (the weight of the fixed pulley 5+the suspension bracket 50) in the folded state, so that the lower ladder is extremely lower. It does not fall and is easy to carry.

In the state where the two safety ladders A are extended and used, the wire w with the hook f fed out from the fall arrester 4 rises behind each lower ladder 1 and emerges in front of the upper ladder 2 at the overlapping portion of the ladders. As the operator walks around the fixed pulley 5 and then hangs down each step bar, when the worker climbs the lower step bar 13 or the upper step bar 23 or falls, the wire w However, it is difficult to interfere with the worker, the lower ladder 1 and the upper ladder 2.

In the double safety ladder A, the length of the wire w is required to be approximately twice as long as that of the ladder for attaching the fall arrester 4 to the upper part of the ladder. Therefore, the length of the wire w wound inside the fall arrester 4 is required. Is approximately doubled, or the wire w is connected to increase the length.

Next, a double safety ladder B (corresponding to claim 3) according to the second embodiment of the present invention will be described with reference to FIGS. 2 and 3.

As shown in FIG. 3, the double safety ladder B includes a lower ladder 1 having a plurality of lower step bars 13 mounted between the lower left support 11 and the lower right support 12, and a plurality of upper ladders between the upper left support 21 and the upper right support 22. The upper ladder 2 to which the step rail 23 is attached, the expansion and contraction fixing means 3 capable of locking the upper ladder 2 at an arbitrary height, the fall arrester 4 having the mounting bracket 10 fixed to the lower portion of the lower ladder, and the uppermost step. The stepping rail 23 is provided with a suspension roller 6 that is suspended by a suspension fitting 50.

The double safety ladder B of the second embodiment differs from the double safety ladder A of the first embodiment in the following points.

The double safety ladder B according to the second embodiment employs the hanging roller 6 instead of the fixed pulley 5.

The hanging roller 6 is provided on the upper surface of the holder 62, and a bobbin-shaped sheep 61 having a V-shaped groove around which the wire w is wound, a holder 62 having a substantially U-shaped cross section that pivotally supports the sheep 61, and a holder 62. The hanging metal fitting 63 is attached to the mounting pin 504, and the hanging metal fitting 63 is hooked on the upper step rail 23.

When the worker steps off the step of the double safety ladder B, the wire w is suddenly pulled out through the sheep 61 of the hanging roller 6, so that the drum 43 rotates at a high speed and the ratchet 47 causes the force of the spring 48. Counter to and pivots about shaft 44 to engage ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, so that the feeding of the wire w is stopped, and the collision of the worker with the ground can be prevented.

In a state where the two safety ladders B are extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each lower ladder 1 and the front surface of the upper step 2 at the overlapping portion of the ladders. It goes up to, goes up, is hung on the sheep 61 of the hanging roller 6, and is then drawn around so as to hang down each step rail.

When transporting or storing the two safety ladders B in a contracted state, the wire w fed from the fall arrester 4 is hung over the sheep 61 of the hanging roller 6 and then slightly hung down. The hook f is locked to the upper step bar 23 below the hanging roller 6.

In a state where the two safety ladders B are extended and used, when the worker steps off the step of the two safety ladders B, the wire w is prevented from falling through the sheep 61 of the hanging roller 6. Since the drum 43 is rapidly pulled out from the No. 4, the drum 43 rotates at a high speed, the ratchet 47 rotates around the shaft 44 against the force of the spring 48, and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the worker's collision with the ground can be prevented.

The double safety ladder B of the second embodiment has the following advantages.

In the double safety ladder B, a relatively heavy fall arrester 4 is fixed to the lower portion of the lower ladder by a mounting member 10. Then, the hanging roller 6 is hung on the upper step rail 23 of the uppermost stage by the hanging metal fitting 50.

Usually, (the weight of the mounting bracket 10 + the weight of the fall arrester 4)> (the suspension roller 6 + the suspension metal fitting 50), so when the two safety ladders B are extended and used, the fall arrester 4 and the suspension roller 6 are attached. The center of gravity is lower than that of a double ladder.

When the two safety ladders B are extended and used, the center of gravity is lowered. Therefore, when the two safety ladders B are leaned against a house that is a work, the two safety ladders B may fall or fall. hard.

When the two safety ladders B are extended and used, the center of gravity is lowered. Therefore, even after the two safety ladders B are leaned against the house, the operator may move the lower step 13 and the upper step 23 up and down. Difficult to get on and it is difficult for the operator to step off the crossing.

When the two safety ladders B are folded, the (weight of the mounting bracket 10 + weight of the fall arrester 4) is offset to some extent by (weight of the hanging roller 6 + weight of the suspension bracket 50). The bottom of the ladder does not go down extremely and is easy to carry.

In a state where the two safety ladders B are extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each lower ladder 1 and emerges in front of the upper ladder 2 at the overlapping portion of the ladders. When the operator climbs the lower step rail 13 or the upper step rail 23, the upper ladder 2 is lifted and the front of each upper ladder 2 is hung up and suspended around the hanging roller 6, and then the ladders are drawn around. It is difficult for the wire w to interfere with the worker, the lower ladder 1 and the upper ladder 2 when the robot falls.

In the double safety ladder B, the length of the wire w is required to be approximately twice as long as that of the ladder for mounting the fall arrester 4 on the upper part of the ladder. Therefore, the length of the wire w wound inside the fall arrester 4 is required. Is approximately doubled, or the wire w is connected to increase the length.

The hanging roller 6 has a deep V groove in the spool 61, so that the wire w is less likely to come off than the fixed pulley 5.

Next, a double safety ladder C according to the third embodiment of the present invention (corresponding to claim 4) will be described with reference to FIGS. 2 and 4.

As shown in FIG. 4, the double safety ladder C includes a lower ladder 1 having a plurality of lower step bars 13 mounted between the lower left support 11 and the lower right support 12, and a plurality of upper ladders between the upper left support 21 and the upper right support 22. The upper ladder 2 to which the step rail 23 is attached, the expansion and contraction fixing means 3 capable of locking the upper ladder 2 at an arbitrary height, the fall preventer 4 fixed to the lower portion of the lower ladder by the mounting bracket 10, and the uppermost stage. It is provided with a hanging wheel 7 that can be hung on the upper step rail 23.

The double safety ladder C of the third embodiment differs from the double safety ladder A of the first embodiment in the following points.

The double safety ladder C according to the third embodiment employs a hanging wheel 7 instead of the constant pulley 5.

The hanging wheel 7 includes a bobbin-shaped sheep 71 to which the wire w is hung, a holder 72 having a substantially U-shaped cross section that rotatably supports the sheep 71, and an engagement fitting 73 extending from an upper end of the holder 72. And a structure in which one side of the holder 72 is opened when the lever 74 is operated.

The hanging metal wheel 7 is hung down to the upper step rail 23 of the uppermost stage by fitting the engaging fitting 73 into the shaft of the hanging fitting 70.

When the worker steps off the step of the double safety ladder C, the wire w is suddenly pulled out through the sheep 71 of the hanging wheel 7, so that the drum 43 rotates at a high speed and the ratchet 47 moves the spring 48. It rotates around the shaft 44 against the force and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, so that the feeding of the wire w is stopped, and the collision of the worker with the ground can be prevented.

The wire w with the hook f fed from the fall arrester 4 rises behind the lower ladder 1 and comes out to the front of the upper step bar 2 at the overlapping portion of the ladder and rises to be hung on the sheep 71 of the hanging wheel 7. After being handed over, they are drawn around to hang down.

When transporting or storing the two safety ladders C in a contracted state, the lever 74 is operated to open one side of the holder 72 and the wire w with the hook f is attached to the sheave of the hanging wheel 7. After removing from 71, the two safety ladders C are folded.

In the unlikely event that the worker steps off the step of the two safety ladders C, the wire w is suddenly pulled out from the fall arrester 4 via the sheep 71 of the hanging wheel 7, so that the drum 43 is removed. Rotating at a high speed, the ratchet 47 rotates around the shaft 44 against the force of the spring 48 and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the collision with the ground can be prevented.

The double safety ladder C according to the third embodiment has the following advantages.

In the double safety ladder C, the relatively heavy fall arrester 4 is fixed to the lower portion of the lower ladder by the mounting bracket 10, and the hanging rail 7 is hung on the upper step rail 23 of the uppermost stage.

In addition, since the two safety ladders C are (the weight of the mounting bracket 10+the weight of the fall arrester 4)>(the weight of the hanging wheel 7+the weight of the hanging bracket 70), the fall prevention is performed in the extended state. The center of gravity of the double safety ladder C is lower than that of the double safety ladder without the vessel 4 and the hanging wheel 7.

Since the center of gravity of the two safety ladders C is lowered when they are extended and used, it is difficult for the safety ladders C to fall or fall when leaning against a work house.

Since the center of gravity of the double safety ladder C is lowered in the extended use state, even when the worker steps up and down the lower step rail 13 and the upper step rail 23 after leaning the double safety ladder C on the house. Difficult to grind and it is difficult for the operator to step off the step rail.

The two safety ladders C are carried because the (mounting metal fitting 10+weight of the fall arrester 4) is offset to some extent by (weight of the hanging metal wheel 7+weight of the hanging metal fitting 70) in the unextended state. In this case, the lower part of the lower ladder does not go down extremely and it is easy to carry.

In the state in which the double safety ladder C is extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each lower ladder 1 and reaches the front of the upper ladder 2 at the overlapping portion of the ladders. When the worker climbs up the lower step rail 13 or the upper step rail 23 or falls, the operator pulls out and raises the front surface of each upper ladder 2 and hangs them around the hanging wheel 7 and then hangs them down. , The wire w does not easily interfere with the worker, the lower ladder 1 and the upper ladder 2.

The double safety ladder C requires approximately twice the length of the wire w as compared with the conventional double safety ladder in which the fall arrester 4 is attached to the upper part of the ladder. The length of the wire w to be cut is approximately doubled, or the wire w is connected and lengthened.

Since the sheave 71 of the hanging wheel 7 has a pincushion shape, the wire w is less likely to come off than the fixed pulley 5.

When the lever 74 is operated, one side of the holder 72 is opened, so that the wire w can be removed from the sheep 71 of the hanging wheel 7. Therefore, it is convenient when transporting or storing the double safety ladder C.

Next, a double safety ladder D (corresponding to claim 2) according to the fourth embodiment of the present invention will be described with reference to FIG.

The double safety ladder D has a lower ladder 1 having a plurality of lower step bars 13 attached between the lower left support 11 and a lower right support 12, and a plurality of upper support rails 23 installed between an upper left support 21 and an upper right support 22. The upper ladder 2, the expansion and contraction fixing means 3 capable of locking the upper ladder 2 at an arbitrary height, the fall preventer 4 fixed to the lower portion of the upper ladder by a mounting bracket 9, and the suspension bracket 8 on the upper step bar 23. And a fixed pulley 5 that is suspended.

The double safety ladder D of the fourth embodiment differs from the double safety ladder A of the first embodiment in the following points.

The fall arrester 4 is surrounded by an upper step bar 23 which is two steps from the bottom, an upper step bar 23 which is one step above the left step bar, and upper left and right support columns 11 and 12 which face between the upper step bars 13-13. It is fixed to the lower part of the upper ladder by a mounting bracket 9.

The mounting bracket 9 has a substantially U-shaped cross section, and is bolted to the upper step bar 23 which is two steps from the bottom of the upper ladder 2 and the upper step bar 23 which is one step above the upper step bar 23.

Then, in a state in which the two safety ladders D are extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each upper step bar 23 and is hung on the sheep 51 of the constant pulley 5. After that, it is routed so as to hang down the front of each step.

In the state where the two safety ladders D are extended and used, in the unlikely event that the worker steps out of the stepping rails of the two safety ladders D, the wire w falls through the sheep 51 of the constant pulley 5. Since the drum 43 is rapidly pulled out from the preventer 4, the drum 43 rotates at high speed, the ratchet 47 rotates around the shaft 44 against the force of the spring 48, and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the collision with the ground can be prevented.

In addition, when transporting or storing the two safety ladders D in a contracted state, the wire w fed from the fall arrester 4 is hung over the sheep 51 of the constant pulley 5 and then slightly hung down. The hook f is locked to the upper step bar 23 below the constant pulley 5.

Next, a series of safety ladders E (corresponding to claim 5) according to the fifth embodiment of the present invention will be described with reference to FIGS. 2 and 6.

As shown in FIG. 6, the series of safety ladders E includes a ladder 100 in which a plurality of cross rails 115 are mounted between the left support 113 and the lower right support 114, and a fall arrester 4 fixed to the lower part of the ladder by a mounting bracket 10. The step pulley 115 is provided with the fixed pulley 5 that is suspended by the suspension fitting 50.

The series of safety ladders E of the fifth embodiment differ from the double safety ladder A of the first embodiment in the following points.

Since the series of safety ladders E is a single ladder, the expansion and contraction fixing means 3 is not attached.

The fall arrester 4 is fixed by a mounting bracket 10 to the lower portion of the ladder surrounded by the lowermost step rail 115 and the left and right columns 113 and 114 located below the step rail 115.

The fixed pulley 5 includes a disk-shaped sheep 51 having a groove formed around the wire w, and a shaft frame holder 53 with a suspension hole that pivotally supports the sheep 51 with a shaft 52.

The suspension metal fitting 50 includes a top plate 501, hanging pieces 502 and 502 with holes that hang down from the lower surface of the top plate 501, and bolts and nuts 503 for fixing the top plate 501 to the uppermost step rail 115. It consists of a hole in the hanging piece 502 and a mounting pin 504 fitted in a suspension hole in the shaft frame holder 53, and the constant pulley 5 is hung on the lower central surface of the uppermost step rail 115.

The left column 111 and the right column 112 are hollow aluminum pipes having a rectangular cross section and a length of several meters. Ends 111 and 112 for slip prevention are attached to the lower ends of the left support 11 and the right support 12.

The left column 111 and the right column 112 are arranged side by side at intervals of several tens of centimeters, and seven step rails 115 are attached at equal intervals between the left column 111 to the right column 112.

End caps 116 and 117 for preventing injury are attached to the upper ends of the left column 111 and the right column 112.

Next, a method of using the series of safety ladders E of Example 5 will be described.
(1) Carry a series of safety ladders E to the work site and place them on the ground near the roof of the house (work). Then, the hook f is removed from the step rail 115 (for example, the second step rail from the top), and the wire w is pulled out at a speed that does not exceed the limit value and the dimension of the step rail.

In addition, when the series of safety ladders E is not used (during transportation or storage), the wire w fed from the fall arrester 4 is made to face the back of each ladder 115 and is hung on the sheep 51 of the constant pulley 5. After that, the hook f is locked to one of the step rails 115 (for example, the second step rail from the top).
(2) A series of safety ladders E are leaned against the house at an installation angle of 75 degrees. Then, the hook f of the wire w is fitted into the carabiner of the worker's safety belt.
(3) The worker climbs up a series of safety ladders E from the lowest step rail 115 of the ladder 100 to reach the roof of the house.

In the unlikely event that the worker steps out of the steps of the safety ladder E, the wire w is suddenly pulled out from the fall arrester 4 via the sheep 51 of the constant pulley 5, so that the drum 43 rotates at high speed. Then, the ratchet 47 rotates around the shaft 44 against the force of the spring 48 and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the collision with the ground is prevented.

The series of safety ladders E of Example 5 have the following advantages.

In a series of safety ladders E, a relatively heavy fall arrester 4 is fixed to the lower part of the ladder by a mounting bracket 10, and a fixed pulley 5 is hung by a suspension bracket 50 on the uppermost step rail 115.

As a result, (the weight of the mounting bracket 10 + the weight of the fall prevention device 4)> (the weight of the constant pulley 5 + the weight of the suspension metal 50), the series of ladders when used is smaller than the ladder without the fall prevention device 4 and the constant pulley 5. The safety ladder E has a lower center of gravity.

When the series of safety ladders E is used, the center of gravity is lowered, and therefore, when the series of safety ladders E is leaned against a house, which is a work, the series of safety ladders E is difficult to grapple or fall.

When the series of safety ladders E is used, the center of gravity is lowered. Therefore, even after the series of safety ladders E have been leaned against the house, the series of safety ladders E are less likely to grind even when the worker moves up and down the step 115. Is difficult to take off from the crossing.

In the series of safety ladders E, (the weight of the mounting bracket 10+the weight of the fall preventer 4) is offset to some extent by the (weight of the fixed pulley 5+the weight of the suspension bracket 50), so that the lower part of the ladder does not drop extremely and is easy to carry.

When a series of safety ladders E are used, the wire w with the hook f fed from the fall arrester 4 rises behind the ladder 100, is hung on the fixed pulley 5, and then hangs down on the front surface of each step 115. Because of the configuration, the wire w is unlikely to interfere with the worker or the ladder 115 when the worker climbs or crosses the step rail 115.

In addition, in the series of safety ladders E, the length of the wire w is required to be approximately twice as long as that of the ladder for mounting the fall arrester 4 on the upper part of the ladder. Double the length or connect the wire w to make it longer.

Next, a triple safety ladder F (corresponding to claim 6) according to the sixth embodiment of the present invention will be described with reference to FIGS. 2 and 7.

As shown in FIG. 7, the triple safety ladder F includes a lower ladder 1 having a plurality of lower step bars 13 mounted between the lower left support 11 and the lower right support 12, and a plurality of upper ladders between the upper left support 21 and the upper right support 22. The upper ladder 2 having the step bars 23 attached thereto, the middle ladder 90 having a plurality of the middle step columns 93 attached between the left middle support column 91 to the right middle support column 92, and the expansion and contraction capable of locking the upper ladder 2 at an arbitrary height. The fixing means 30, the expansion and contraction fixing means 31 capable of locking the middle ladder 90 at an arbitrary height, the fall preventer 4 fixed to the lower portion of the lower ladder by the mounting bracket 10, and the hanging bracket 8 on the upper step rail 23. And a fixed pulley 5 that is suspended.

The triple safety ladder F of the sixth embodiment differs from the double safety ladder A of the first embodiment in the following points.

The left middle pillar 91 and the right middle pillar 92 of the middle ladder 90 are hollow aluminum pipes having a rectangular cross section and a length of several meters. The middle pillar 91 and the right middle pillar 92 are juxtaposed at intervals of several tens of centimeters, and seven middle step bars 93 are attached between the left middle pillar 91 to the right middle pillar 92.

The expansion/contraction fixing means 30 is composed of brackets 301 and 302, stoppers 303, locks, racks and the like, supports the upper ladder 2 movably up and down behind the middle ladder 90, and supports the upper ladder 2 at an arbitrary height. It is a known mechanism that can be locked with.

The expansion/contraction fixing means 31 is composed of brackets 311, 312, stoppers 313, locks, racks, and the like, supports the middle ladder 90 up and down behind the lower ladder 1, and supports the middle ladder 90 at an arbitrary height. It is a known mechanism that can be locked with.

The fall arrester 4 has a structure that locks when the drawing speed of the wire w exceeds a limit value (see FIG. 2). Similar to the first embodiment, this fall preventer 4 is provided with a mounting bracket 10 at the lower portion of the lower ladder surrounded by the lower step rail 13 at the lowermost stage and the left and right lower columns 11 and 12 located below the lower step rail 13. Fixed by.

The fixed pulley 5 is suspended from the upper step rail 23 by a suspension fitting 8.

In a state where the three safety ladders F are extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each step rail and is stretched over the sheep 51 of the constant pulley 5. It is routed so as to hang down the front of each step.

Next, a method of using the triple safety ladder F of the sixth embodiment will be described.
(1) Carry three safety ladders F to the work site and place them on the ground near the roof of the house (work). Then, the hook f is detached from the step rail (for example, the lower step rail 13), and the wire w is pulled out at a speed not exceeding the limit value by about the dimension of the step rail.

When the three safety ladders F are in a contracted state (during transportation or storage), the wire w fed from the fall arrester 4 is lifted behind the step rails of each ladder to the sheep 51 of the constant pulley 5. After being hung, the hook f is locked to the step rail (for example, the lower step rail 13).
(2) With the three safety ladders F folded down, the latches 303 and 313 are unlocked, the upper ladder 2 and the middle ladder 90 are extended to the maximum length, and the latch 303 is placed on the uppermost stage of the middle ladder 90. The upper ladder 2 and the middle ladder 90 are fixed by engaging the middle ladder 93 and the clasp 313 on the uppermost lower ladder 13 of the lower ladder 1.
(3) Lean the three extended safety ladders F against the house at an installation angle of 75 degrees. Then, the hook f of the wire w is fitted into the carabiner of the worker's safety belt.
(4) The worker starts to climb the three safety ladders F from the lower ladder 1 of the lower ladder 1, changes to the middle ladder 93 of the middle ladder 2 at the joint, and then rises above the upper ladder 2 at the joint. In the unlikely event that the operator changes to the step 293 and reaches the roof of the house, if the worker steps off from any step of the three safety ladders F on the way to the ascending, the sheep 51 of the constant pulley 5 is used. Since the wire w is suddenly pulled out from the fall arrester 4, the drum 43 rotates at a high speed, the ratchet 47 rotates around the shaft 44 against the force of the spring 48, and meshes with the ratchet wheel 46.

As a result, the rotation of the drum 43 is blocked, the feeding of the wire w is stopped, the fall of the worker is interrupted, and the collision with the ground is prevented.

The triple safety ladder F of the sixth embodiment has the following advantages.

The triple safety ladder F has a relatively heavy fall arrester fixed to the lower portion of the lower ladder 1 by the mounting bracket 10. The fixed pulley 5 is suspended by the suspension metal fitting 8 on the upper step rail 23 of the uppermost stage of the upper ladder 2.

As a result, (the weight of the mounting bracket 10 + the weight of the fall arrester 4)> (the weight of the constant pulley 5 + the weight of the suspension bracket 8), the three safety ladders F and the fall arrester 4 and the constant weight in the state of being extended and used. The center of gravity is lower than the conventional triple ladder without the pulley 5.

Since the center of gravity of the three safety ladders F is lowered in the extended state, it is difficult for the three safety ladders F to fall or fall when leaning against the house as a work.

When the three safety ladders F are extended and used, the center of gravity is lowered. Therefore, even when the worker steps up and down the lower step bar 13 and the upper step bar 23 after leaning against the house, it is difficult for the operator to step on them. It is difficult to step off the crosspiece.

In the folded state, the three safety ladders F are offset to some extent by (the weight of the mounting bracket 10 + the weight of the fall arrester 4) (the weight of the fixed pulley 5 + the weight of the suspension bracket 8). It does not fall and is easy to carry.

In a state where the three safety ladders F are extended and used, the wire w with the hook f fed from the fall arrester 4 rises behind each ladder and is hung on the fixed pulley 5 and then the front surface of each step. Since the wire is hung so as to hang down, when the worker climbs the lower step bar 13, the middle step bar 91, and the upper step bar 23 or falls, the wire w is used by the worker, the lower ladder 1, and the middle step bar. It is difficult to interfere with 91 or the upper ladder 2.

Note that the triple safety ladder F requires about three times the length of the wire w as compared with the ladder that attaches the fall arrester to the upper part of the triple safety ladder, and therefore is wound inside the fall arrester 4. The length of the wire w is approximately tripled, or the wire w is connected midway to make it longer.

The present invention includes the following embodiments in addition to the above embodiments.
a. The upper step of the upper ladder of the upper ladder that suspends the fixed pulley, the hanging roller, or the hanging wheel receives downward force when the worker falls, so a reinforcement that supports the end of the upper step from below is used. You may attach it to.
b. In the double safety ladder of the first to fourth embodiments, since the wire w that is longer than the ladder that attaches the fall arrester 4 to the upper part of the ladder is required, the length of the wire w wound inside the fall arrester 4 is long. The length is approximately doubled or the wire w is connected midway to lengthen it.

In addition, in the triple safety ladder of the sixth embodiment, a longer wire w is required as compared with the triple ladder in which the fall arrester 4 is attached to the upper part of the ladder. The length is approximately tripled or the wire w is connected midway to make it longer.
c. The pulley-shaped body according to claims 5 and 6 (Examples 5 and 6) may be a hanging roller 6 or a hanging wheel 7 in addition to the constant pulley 5.
d. The cord-like body may be a strip-shaped body having a rectangular cross-section, in addition to the wire w having a circular cross-section. e. From the viewpoint of lowering the center of gravity, the position of the lower part of the ladder to which the fall arrester is fixed is preferably a place surrounded by the lowest step pedestal and the left and right stanchions below the step pedestal, but from the lowest step, Alternatively, it may be a place surrounded by a two-tiered crossing pedestal and left and right struts located below the pedestal.

A, B, C, D Double safety ladder
E series of safety ladders
F Triple safety ladder
w wire (cord)
1 lower ladder
2 Upper ladder
3 telescopic fixing means
4 fall arrester
5 Constant pulley (constant pulley, pulley-like body)
6 hanging roller
7 Suspended metal wheel 9, 10 Mounting bracket
11 Lower left column
12 Lower right column
13 Lower step
21 Upper left column
22 Upper right column
23 Upper rail 8, 50 Suspension metal fitting
70 Hanging bracket
90 Middle ladder
91 Left center column
92 Right center post

Claims (6)

Left and right lower columns that are erected at a predetermined interval, and a lower ladder having a plurality of lower step bars attached at different height positions of these left and right lower columns,
Left and right upper struts which are erected at a predetermined interval, and an upper ladder having a plurality of upper step bars attached at different height positions of these left and right upper struts,
A double station equipped with telescopic fixing means that locks the upper ladder that can move up and down behind the lower ladder at an arbitrary height, and a fall arrester that locks when the drawing speed of the cord exceeds a limit value. Safety ladder of
The fall arrester is fixed to the lower part of the lower ladder with a mounting bracket,
A fixed pulley is hung on the upper cross rail of the uppermost stage with hanging metal fittings,
The hooked cord extended from the fall arrester rises behind each lower ladder, rises to the front of the upper step at the overlapped portion of the ladder, and is then stretched over the fixed pulley before each. A double safety ladder characterized by being drawn around the front of the cross rail. Left and right lower columns that are erected at a predetermined interval, and a lower ladder having a plurality of lower step bars attached at different height positions of these left and right lower columns,
Left and right upper struts which are erected at a predetermined interval, and an upper ladder having a plurality of upper step bars attached at different height positions of these left and right upper struts,
A double station equipped with a telescopic fixing means that locks the upper ladder that can move up and down behind the lower ladder at an arbitrary height, and a fall arrester that locks when the drawing speed of the cord exceeds a limit value. Safety ladder of
The fall arrester is fixed to the lower part of the upper ladder with a mounting bracket,
A fixed pulley is hung with a suspension metal fitting on the upper step of the uppermost stage,
The hook-shaped cord extending from the fall arrester rises behind each upper step rail, is stretched around the fixed pulley, and then is drawn around to hang down the front surface of each step rail. And two safety ladders. Left and right lower columns that are erected at a predetermined interval, and a lower ladder having a plurality of lower step bars attached at different height positions of these left and right lower columns,
Left and right upper struts which are erected at a predetermined interval, and an upper ladder having a plurality of upper step bars attached at different height positions of these left and right upper struts,
A double station equipped with telescopic fixing means that locks the upper ladder that can move up and down behind the lower ladder at an arbitrary height, and a fall arrester that locks when the drawing speed of the cord exceeds a limit value. Safety ladder of
The fall arrester is fixed to the lower part of the lower ladder with a mounting bracket,
Suspension rollers are hung on the upper step rails on the top stage with hanging metal fittings
The hooked cord extending from the fall arrester rises behind each lower ladder, rises to the front of the upper step bar at the overlapping portion of the ladder, and is suspended from the hanging roller after each. A double safety ladder characterized by being drawn around the front of the cross rail. Left and right lower columns that are erected at a predetermined interval, and a lower ladder having a plurality of lower step bars attached at different height positions of these left and right lower columns,
Left and right upper struts which are erected at a predetermined interval, and an upper ladder having a plurality of upper step bars attached at different height positions of these left and right upper struts,
A double station equipped with telescopic fixing means that locks the upper ladder that can move up and down behind the lower ladder at an arbitrary height, and a fall arrester that locks when the drawing speed of the cord exceeds a limit value. Safety ladder of
The fall arrester is fixed to the lower part of the lower ladder with a mounting bracket,
A hanging wagon is hung down on the upper step of the upper step,
The hook-shaped cord extending from the fall arrester rises behind each lower ladder, rises to the front of the upper step rail at the overlapping portion of the ladder, and rises over the suspension wagon. A double safety ladder characterized by being drawn around the front of each cross rail. Left and right struts standing upright at a predetermined interval, and a ladder having a plurality of step rails attached at different height positions of these left and right struts
A series of safety ladders equipped with a fall arrester that locks when the withdrawal speed of the cord exceeds the limit value.
The fall arrester is fixed to the bottom of the ladder with a mounting bracket,
A pulley-shaped body is attached to the top step,
The hooked cord extending from the fall arrester rises behind each step of the ladder, is hung on the pulley and then is drawn around the front of each step. A series of safety ladders characterized by that. Left and right lower columns that are erected at a predetermined interval, and a lower ladder having a plurality of lower step bars attached at different height positions of these left and right lower columns,
Left and right upper struts which are erected at a predetermined interval, and an upper ladder having a plurality of upper step bars attached at different height positions of these left and right upper struts,
Right and left middle columns that are erected at a predetermined interval, and one or more middle ladders that have a plurality of middle step bars attached at different height positions of these left and right center columns,
A plurality of telescopic fixing means for locking each vertically movable ladder except the lower ladder at an arbitrary height position,
A safety ladder of multiple lines equipped with a fall arrester that locks when the withdrawal speed of the cord exceeds the limit value,
The fall arrester is fixed to the lower part of the ladder of one of the ladders by a mounting bracket,
A pulley-like body is attached to the upper step rail of the upper ladder,
The multiple ladder in which the hook-shaped cord extending from the fall arrester is hung around the pulley and then hung so as to hang down the front surface of each step.

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