JPH0369790A - Positioning coupling for folding ladder - Google Patents

Abstract

PURPOSE: To lock a foldable ladder at a prescribed angle position by freely rotatably coupling two coupling members having longitudinal beam mounting parts and a rotating plate by a shaft means and aligning an engagement hole and an alignment hole. CONSTITUTION: A first outside coupling member 12 having a longitudinal beam mounting part 34 and first and second disc parts 20, 24 and a second inside coupling member 14 having a longitudinal beam mounting part 35 and a third disc part 54 are provided. Next, the first to third disc parts 20, 24, 54 and a rotating plate 72 are freely rotatably coupled by inserting a shaft means into each center hole 42, 68, 74, 44. Further, a rotation limiting means, first and second deflection means and a locking yoke 98 are provided. An engagement hole 70 and an alignment hole 76 provided on each of the disc parts 20, 24, 54 and the rotating plate 72 are aligned at a specified angle position and a foldable ladder is locked at the position.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates generally to folding ladders, and more particularly to locating joints for folding ladders.

"Problems to be solved by conventional techniques and inventions" Conventionally,
The positioning joint for a folding ladder includes a first joint member having a vertical mounting portion and a disc portion, and a second joint member having a vertical mounting portion and a disc portion, the first and second joint members having a vertical mounting portion and a disc portion. The disc portions of the members are coaxially coupled to each other and rotatable with respect to each other to fold or unfold the ladder to the desired angular position. Each disk section has a hole formed therein that is aligned with a hole in the other disk section at a predetermined angular position of the folding ladder.

In this case, when the holes in one disc section are aligned at a particular angular position, pins are inserted into the holes in order to lock the folding ladder in that position. however,
It is difficult to quickly align the holes in the two disc parts to change the angular position of the ladder. In particular, when changing the angular position of the ladder, the pin is completely removed, the disc parts of the first and second coupling members are rotated relative to each other until the separate holes are aligned with each other, and then the folding ladder is The pin must be inserted into the hole again to lock it in the new angular position.

The locating joint described in Kummerlin U.S. Pat. No. 3,811,151 consists of two circles that are secured to each vertical mounting portion and rotate with respect to each other so that the ladder can be configured as a stepladder or a payout ladder. The disk portions including the plate portions are rotatably fixed to each other by hinge pins and have holes aligned with each other at a plurality of different positions in the flange portions. A generally U-shaped locking rod is provided having a first leg defining a guide rod that is slidably restrained within the hinge pin and is normally biased into the hinge pin by a coiled spring. The second parallel leg constitutes a locking rod that is inserted into an aligned hole in the disc portion to rotatably lock the disc portions together in a fixed position. This locking allows the ladder to be locked in either a closed configuration, a stepladder configuration, or an extended ladder configuration. By grasping the yoke that connects the guide rod and the locking rod 2 with the user's hands and pulling the guide rod outward from the hinge pin, the locking rod can be pulled out from the predetermined hole. However, the user must simultaneously hold the yoke outwardly against the force of the coil spring and rotate the disc parts relative to each other in order to move the ladder to another position, which is inconvenient.

Klafs, US Pat. No. 4,218,844, describes a locating joint of the aforementioned type in which two locking pins are held in a retracted position while the ladder sections are rotated with respect to each other. After the ladder sections have been rotated slightly with respect to each other, the locking pins are automatically released from their holding position and pulled inwardly into contact with the outer surface of one of the disk sections on which they rest. As the ladder parts are further rotated with respect to each other, the holes in the disc parts become aligned with each other and the locking pins fit into the aligned holes to engage the ladder in position.

The ladder hinge described in U.S. Pat.
This gives almost the same final result as No. 4. In these two patents, the means for holding the locking handle in an outwardly retracted position is constituted by a spring-ball detent assembly. Another configuration comparable to this is ummer
lin, US Pat. No. 4,403,373.

However, in the above-cited Kumserlin patent and the 9oothe and Klatg patent, the arrangements for retaining the locking pin in the outwardly retracted position are relatively complex.

Martinezc7) U.S. Patent No. 4,152,810
The automatically interlockable hinges described in the No. 2003-12-1000-3 have a linkage that operates a key to engage the key within a plurality of apertures spaced circumferentially around the hinge. use. This mechanism is even more complex than those described above, making ladder hinges extremely complex and costly.

U.S. Pat. No. 4,886,328 to Ryu discloses a positioning joint that includes a rotating plate rotatably disposed between an inner disc portion of one joint member and an outer disc portion of another joint member. Are listed. Rotational movement of the locking plate is restricted between a first position and a second position, and a spring is provided to bias the locking plate normally to the first position. This patent further requires the use of a specially arranged double aperture in the inner disc part, with a crank-shaped strip fixed to the inner surface of the other outer disc part. The crank-shaped strip includes two pairs of protrusions, and six pairs of protrusions are arranged inside different holes in the inner disc part in response to depression of the push knob and rotation of the inner disc part with respect to the outer disc part. engage. However, from a manufacturing process point of view, such positioning joints are relatively complex, require a large number of parts, and are fairly complex to assemble, making the ladder expensive.

In all of the above-mentioned patents, the ladder is opened in steps, each step being defined by a predetermined angular position set by an array of holes that engage locking pins.

However, such gradual angle changes also apply when closing the ladder. Although it is advantageous to open the ladder in several stages, it may be desirable to close the ladder at once, ie without stopping each time the hole is aligned at a predetermined angular position.

According to the prior art, it is also known to utilize a ratchet mechanism to selectively lock the ladder in a desired angular position. However, such ratchet mechanisms are prone to malfunction when significant weight is applied to the ladder, raising concerns about user safety.

Other devices that are not related to the above-mentioned patents, but which are believed to be relevant, include Vigo U.S. Pat. No. 4,377.
No. 020 and Quiogue U.S. Pat. No. 4,543.
, No. 007.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a positioning joint for a folding ladder which overcomes the problems encountered in the prior art.

Another object of the invention is to provide a positioning joint for a folding ladder that has a minimum number of parts that can be easily assembled together.

Yet another object of the invention is to provide a positioning joint for a folding ladder that is extremely safe to operate and use.

Yet another object of the invention is to provide a positioning joint for a folding ladder in which the opening of the ladder can only take place in stages, while the closing can take place all at once.

According to Ikko in January of Kihatsu, a positioning joint for a folding ladder has a vertical mounting part and first and second disc parts, each disc part has a center hole, and t5 is a circular part. The plate portion includes a first coupling member having at least one locating hole and a vertical mounting portion.

a third disk portion having a central hole and a plurality of engagement holes arranged along the circumferential direction, the third disk portion having at least one positioning hole; a second coupling member disposed between the first disc portion of the first coupling member and the second disc portion of the first coupling member such that the first disc portion of the first coupling member can be aligned with the hole; is rotatably arranged between the inner wall of the disk portion of the second coupling member and the third disk portion of the second coupling member, and has a center hole and a third disk portion of the second coupling member in a circumferential direction. a rotary plate having at least one alignment hole formed correspondingly to the engagement holes distributed along the rotary plate; and a central hole in the first, second and third disc portions of the first and second coupling members. and the center hole of the rotary plate, and the first
and a shaft means for rotatably coupling the second joint member and the five-rotation plate together, and a rotation limiting means for restricting the rotation of the rotor plate to a predetermined angular range between the first limit and the second limit. a first deflection means for rotating the rotary plate in a first direction to a first limit; a first deflection means extending to an outer surface of the first disc portion; at least one engagement extending into the at least one locating hole and selectively engageable with the at least one alignment hole of the rotating plate and the engagement hole of the third disc portion of the second coupling member; a locking handle having a stop pin; a connecting means having a connecting shaft extending to the outer surface of the second disk portion, passing through the shaft means and being coupled to a connecting portion of the locking handle; and a locking handle. and second deflection means for deflecting inward.

Accordingly, when the locking handle is moved outwardly against the force of the second deflection means, the at least one locking pin is deflected out of the at least one alignment hole and the engagement hole so that the first The deflection means rotate the rotating plate to a first limit, whereupon.

The at least one alignment hole becomes out of alignment with the at least one locating hole, and upon rotation of the first coupling member and the second coupling member relative to each other, the at least one locking pin enters the at least one alignment hole. the at least one locking pin moves along the rotating plate until the first and second coupling members reach one of a plurality of predetermined angular positions; and at least one positioning hole to releasably lock the first and second joint members at predetermined angular positions.

These and other objects, features, and advantages of the present invention will become readily apparent from the following detailed description, which should be understood in conjunction with the accompanying drawings.

"Embodiments" Hereinafter, preferred embodiments of the present invention will be described in detail by way of example with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in this example are not intended to limit the scope of the invention, but are merely illustrative examples. It's nothing more than that.

First, referring to FIGS. 1 to 8, the positioning joint 10 includes a first outer joint member 12 and a second inner joint member 14 that are rotatably connected to each other. 12 is formed by a first joint part 16 and a second joint part 18, the first joint part 16 including a first disc part 20 from which a leg part 22 extends,
The second joint portion 18 similarly includes a second disk portion 24 from which legs 26 extend.
0 and the second disk portion 24 have the same dimensions so that they can be assembled with a space between them as shown in FIGS. 6 and 7. In this case, a spacer member 2 is provided between the legs 22 and 26 to ensure that a space is formed between the first disk portion 20 and the second disk portion 24.
8 is provided and fixed.

Additionally, one leg 22 and 2B is designed to increase the effective width of the leg to ensure that the legs 22 and 2B, once installed, can fit inside a ladder rung (not shown). Width correction members 30 and 32 are respectively fixed to the outer surfaces of.

Here, the legs 22 and 2B, the spacer member 28, and the width correction members 30 and 32 are all integrally connected, and the first
A vertical mounting portion 34 of the outer joint member 12 is formed.

Legs 22 and 2 are used to connect these elements together.
A plurality of apertures 36 may be provided in B, the apertures 36 being aligned with the apertures 38 of the width correction members 30 and 32 and the apertures 40 of the spacer member 28.
The openings 38 of the width correction member 30 are provided with screws (not shown) inserted into the aligned openings of the width correction member 32, the legs 26, the spacer members 28, and the legs 22 to secure these elements together. Threads may be formed to be threadedly received within an aligned opening of the width compensating member 30 to form an elongated mounting portion 34 .

The first joint portion 16 and the second joint portion 18 may each be formed from sheet metal pressed into the desired shape, and the spacer member 28 and width compensating members 30 and 32 may be formed from plastic. Preferably, it is manufactured from a material.

A center hole 42 is formed in the first disc portion 20, and a center hole 42 is formed in the second disc portion 24, and a center hole 42 is formed in the second disc portion 24.
A center hole 44 is formed that is coaxially disposed with respect to center hole 42 when S2 and coupling portion 18 are secured together. As shown in FIGS. 3, 6 and 7, the annular boss 4
5 is a second disc portion 24 surrounding the center hole 0;
is fixed to the outer surface of the Furthermore, the first disc portion 20 is
Similarly, the second disc part 24 contains two directly opposite locating holes 4B and 4B which are formed to bulge outwards at 47 and 43 respectively during stamping of this part. Also, two directly opposite positioning holes 5 are formed to bulge outward at points 51 and 53, respectively, during stamping of this part.
The locating holes 50 and 52 are aligned with the locating holes 60 and 48 when the first fitting portion 16 and the second fitting portion 18, including the locating holes 60 and 52, are secured together.

The second inner joint member 14 is connected to the first joint portion 18 or the second inner joint member 14.
is formed similarly to any of the joint portions 18 of. In detail, the second inner joint member 14 is connected to the first disc portion 2
0 and a third disc portion 54 having substantially the same dimensions as the second disc portion 24 and disposed therebetween;
Also opening is a leg portion 58 from which a leg portion 5B extends from the disc portion 54 so as to form an angle of preferably 0° to 180° with the legs 22 and 26 when assembled together. 58 and width correction members 80 and 82 having an opening 84.
are secured to opposite sides of leg 5B by screws passing through openings 58 and 84. Here, the opening 84 of the one-width correction member 60 can be formed with a thread for receiving these screws. With this configuration, the width correction members 80 and 62 together with the third disk portion 54 form the other upright mounting portion 35 of the locating joint. The spacer member 28 and the width compensating members 30, 32, 60 and 62 are arranged such that both vertical mounting portions 34 and 35 have the same width as shown most clearly in FIGS. 6 and 7. It will be seen that the dimensions are sized.

The third disc part 54 has a second disc part 2 attached to it during assembly.
An annular rim B6 is formed opposite to the annular rim 6.
6 is open at position S7, which corresponds to the position where leg portion 5B is fixed, for reasons explained below.

Further, the third disc portion 54 is formed with a center hole 88 that is coaxial with the center holes 42 and 44 in the assembled state, and the plurality of engagement holes 70 are formed in the circumferential direction of the third disc portion 54. are placed along the same circle. The engagement holes 70 are arranged as three pairs of holes facing each other, and the six pairs of engagement holes 70 are arranged as three pairs of holes facing each other.
First outer joint member 1 regarding second inner joint member 14
1 locating hole 46 and 4 at 2 selected angular positions
8 and positioning holes 50 and 52. In detail, the engagement hole 70
is the first outer joint member 12 and the second inner joint member 14
locating holes 46 and 48 and locating holes 50 and The first outer joint member 12 and the second inner joint member are preferably aligned with 52! It will be apparent that the same pair of engagement holes 70 are aligned with locating holes 46 and 48 and locating holes 50 and 52 when 4 are at 0 degrees and 180 degrees with respect to each other.

The positioning joint IO further includes a circular rotary plate 72 having dimensions slightly smaller than the third disk portion 54 and rotatably received within its annular rim 6B, the rotary plate 72 being made of sheet metal or the like. A flat plate that is stamped and when placed inside the annular rim BB the third
A center hole 74 is formed coaxially with the center hole 68 of the disc portion 54 of. Furthermore, a rotating plate? 4 includes a plurality, e.g., six, alignment holes 76 arranged with the same radial distance as the engagement holes 70 and arranged in the same angular position as the engagement holes 70 with respect to each other, and each alignment hole 76 , as seen most clearly in FIG. 8, has an arcuate edge 77 that is beveled when viewed in the clockwise direction of FIG.

The rotary plate 72 further includes a single-shaped protruding plate 78 extending radially outwardly and fitting into the open portion 67 of the annular rim 66, thus the open ends 66a and 8 of the annular rim 6B.
8b defines first and second limit stops of the L-shaped protruding plate 78, thereby limiting the rotation of the rotating plate 72 to a predetermined angular range between a first limit position and a second limit position. Two limit positions are defined for L-shaped protruding plate 78
further includes an elongated central slot 80.

One end 84 of the spring pin 82 has a circular shape, and a hook 86 is formed at the other end.The circular end 84 connects the width correction member 62 to the second inner joint member! 4 is disposed between the width compensating member 62 and the leg 5B in alignment with the uppermost respective openings 58 and 84 to receive a screw 65 used to secure it to the leg 56 of 4. . For this purpose, a notch 83 is formed in the width correction member 62 so that the spring pin 82 can move therein. however.

Due to the tightening of the screw 65, the circular end 84 is attached to the leg 5.
6 and the width correction member 62 so as not to rotate.

The spring pin 82 passes through the cutout portion B3, and the hook 8B of the spring pin normally connects the L-shaped protruding plate 78 to the stopper fl.
engages the elongated central slot 80 of the L-shaped projection plate 78 so as to deflect it to a first limit position abutting the L-shaped projection plate 78;

In order to rotatably couple the first joint portion 18, the second inner joint member 14, the one-turn plate 72, and the second joint portion 18 together, the central holes 42, 88, 74 and 44 are A tubular shaft 88 is rotatably inserted into each. tubular shaft 8
To axially lock 8 in place, a rivet or the like (not shown) can be inserted into central hole 44 into frictional engagement with tubular shaft 88 .

An annular flange 90 is formed at one end of the tubular shaft 88, and when the tubular shaft 88 is placed inside the central hole 42, 88, 74 and 0, the annular flange 90 is connected to the first disk portion 20. abuts the outer surface of the

The pushing member 92 is formed by a connecting shaft 84 having a large-diameter head 98 at one end. The connecting shaft 84 has a diameter large enough to fit over the tubular shaft 88 and the first joint portion IB and the second inner joint member 14 .

It has a radial dimension sufficient to rotatably couple rotary plate 72 and second joint portion 18 together.

The locking yoke 98 is formed by an elongated central connecting portion 100 having a central post 102 at the lower end and a central hole 104.
extends completely through central connecting portion 100 and central boss 102 to slidably receive the free end of connecting shaft 94 . Here, the center boss 102 has a side opening 106.
A side opening 95 is formed at the free end of the connecting shaft 84. Therefore, when the i-coupling shaft 94 is inserted through the tubular shaft 88 and inserted into the central hole 104, the pin 108 is positioned on the side surface to lock the free end of the coupling shaft 94 into the central coupling portion 100 of the locking yoke 98. It is inserted into openings 95 and 10B.

Further, an annular recess 110 is formed in the center post 102 so as to surround the center hole 104, so that the center boss 102 can be attached to the disc of tS2 when the positioning joint IO is in the locking position. It will be appreciated that the annular boss 45 is capable of receiving the annular post 45 of the portion 24, which, although formed as part of the second disc portion 24, pivots the tubular shaft 88 as previously described. It will be clear that it can be formed by the head of a rivet (not shown) used for directional locking.

The locking yoke 98 further includes two opposing locking pins 112 and 114 that are secured to opposite ends of the central connecting portion 100 , the locking pins 112 and 114 being secured to the locating holes 50 of the second disk portion 24 . and 52, and are spaced apart from each other by a distance corresponding to the distance between the positioning holes.

Furthermore, a coil spring 11 arranged around the connecting shaft 34
8 is a pusher member 8 (in surrounding relation to the annular flange SO of the tubular shaft 88), as shown in FIGS. 2, 6, and 7.
It extends between the second large-diameter head 9B and the outer surface of the first disk portion 20. The large-diameter head 96 of the push member 92 forms an annular recess 97 that receives one end of the coil spring 118 . In this way, the coil spring tte pushes the pushing member 92 fJI, l
is deflected outwardly away from the disk portion 20 of.

The locking yoke 98 is connected to the i! Because it is connected to the free end of the I-tie shaft 94, the coil spring 116 further deflects the locking yoke 98 inwardly. In this case, 1 positioning holes 50 and 52, alignment hole 76, and engagement hole 70
When the first outer joint member 12 and the second inner joint member 14 are aligned with each other, the locking pins 112 and 114 engage the holes thereof to lock the first outer joint member 12 and the second inner joint member 14 in a predetermined angular position. I can do it.

The opening operation will be explained with reference to FIGS. 6 and 7. When the user pushes pusher member 32 inwardly to the position shown in FIG. 7B, but still remains inside the positioning holes 50 and 52.

In this position, the rotating plate 72 is no longer prevented from rotating, so the spring pin 82 moves the L-shaped protruding plate 78 against the limit stop 88a to the first limit position,
This causes the rotating plate 72 to rotate slightly. At this position, alignment hole 7B is no longer aligned with positioning holes 50 and 52. Therefore, when the force applied by the user to push member 92 is removed, coil spring 118
deflects the pusher member 92 outwardly and the locking yoke 98 inwardly. However, because alignment hole 78 is no longer aligned with positioning holes 50 and 52, the free ends of locking pins 112 and 114
It is only in contact with the surface of 2.

After that, the first outer joint member 12 and the second inner joint member! 4 rotate away from each other, and the locking pins 112 and 114 engage the next pair of 7-line nut holes 76 located directly opposite each other on the rotating plate 72.
It will be appreciated that in such a position, moving along the surface of the locking pin 112 and 114, the locking pins 112 and 114 also do not fit into the engagement hole 70 because the alignment hole 76 is not aligned with the engagement hole 70. , first outer joint member 12
As the and second inner joint members 14 continue to rotate with respect to each other, the rotating plate 72 rotates with the first outer joint member 12 because the locking pins 112 and 114 are engaged within the alignment holes 76. do. Therefore, the rotating plate 72 will be rotated against the force of the spring pin 82. The first outer joint member 12 and the second inner joint member 14 are moving further ahead! Upon slight rotation about L, the engaged alignment holes 78 are aligned with and positioned directly across from the pair of engagement holes 70 located directly across from each other in the third disc portion 54. It fits into the pair of engagement holes 70. It will be seen that in this position, locating holes 4B and 48 are aligned with locating holes 50 and 52, so that locating holes 48 and 48 are also aligned with engagement hole 70, thus locking pins 112 and 114 are located in the positioning holes 50 and 52. by the coil spring tte. The first outer joint member 12 and the second inner joint member 14 are biased to fit into the alignment hole 7B, the engagement hole 70, and the positioning holes 46 and 48 to engage the first outer joint member 12 and the second inner joint member 14 at a predetermined angular position, e.g., 60°. Stop. The first outer joint member 12 and the second
When the inner joint member 14 of
First, start by pushing the push member 92.

To illustrate the closing operation with reference to FIGS. 6 and 7, the user pushes the push member 32 inwardly to the position shown in FIG. 7, whereby the locking yoke 88 is pushed outwardly. , the locking pin 112 is inserted into the positioning holes 46 and 48 . It disengages from engagement hole 70 and alignment hole 76, but still remains within positioning holes 50 and 52. In such a position, the rotary plate 72 is no longer prevented from rotating, so the spring pin 82 moves the L-shaped protruding plate 7B against the limit stop 86a to the first limit position, thereby causing the rotary plate 72 to move. Rotate slightly. In this position, alignment large 7B is
0 and 52 will no longer be aligned. Thus, when the force that the user has applied to the pusher member 92 is removed, the coil spring II6 deflects the pusher member 92 outwardly and the locking yoke 98 inwardly. However, since alignment hole 76 is no longer aligned with locating holes 50 and 52, locking pin 112 and! +4 is only in contact with the surface of the rotating plate 72.

Thereafter, the first outer joint member 12 and the second inner joint member 14 are rotated so as to approach each other, and the locking pin 112
and 114 rotate plate 7 until it engages the next pair of alignment holes 78 located directly opposite each other.
It can be seen that in such a position, where the locking pins 112 and 114 move, the alignment hole 7B is not engaged with the engagement hole 70, and the locking pins 112 and 114 are also not engaged with the engagement hole 70. Will.

When the closing rotational force is continuously applied to the first inner joint member 12 and the second outer joint member 14, the rotary plate 72 is prevented from rotating further due to the contact between the L-shaped protruding plate 78 and the limit stopper 86a. However, since the alignment hole 76 is formed with an inclined edge 77 only in the clockwise direction, the locking pins 112 and 114 ride on the surface of the rotating plate 72 along the respective inclined edge 77. Therefore, each time the locking pins 112 and 114 fit into the alignment holes 76, they ride on the surface of the rotating plate 72 along their respective sloped edges 77. This operation continues until the locating joint reaches the fully closed position, i.e. the position O''', so there is no need to continue operating the push member S2, i.e. it is only necessary to operate the push member 82 once, and then , the positioning joint lO can be moved to the closed position.

Next, a positioning joint 210 according to another embodiment of the present invention will be described with reference to FIGS. 9 to 11.

In FIGS. 9 to 11, elements corresponding to those previously described with respect to the embodiment of FIGS. 1 to 8 are designated by the same reference numerals plus 200 for the sake of brevity. Therefore, a detailed explanation of those elements will be omitted.

This locating joint 210 is advanced in that the coil spring 316 fits inside the tubular shaft and is therefore disposed within the locating joint 210, as shown most clearly in FIG. This positioning joint 10 is different from the one shown in FIG.

In this regard, as shown in FIG.
The second connecting shaft 294 includes a first portion 299 fixed to the large-diameter head 29B, and a second portion 299 having a smaller diameter than the first portion 299 and fixed to the other end of the first portion 289. The part 301 is shown in the figure. Therefore, the first part 29
An annular shoulder 303 is formed between 9 and the second portion 301, and one end of a coil spring 3113 abuts on this shoulder.

As mentioned above with respect to the positioning joint lO, the tubular shaft 8
Rivets may be provided to axially secure 8 into the central holes 42, 68, 74 and 44.

Therefore, as shown in FIGS. 9 and 1O, the tubular shaft 30
7 and an annular flange 303 at one end thereof, the rivet 305 has its tubular shaft 307 forming a friction fit with the tubular shaft 288, thereby aligning the tubular shaft 288 with the central hole 242.
, 268 , 274 and 244 , thereby passing through the central hole 20 of the second disc portion 224 . As shown in FIG. 11, the annular flange 309 has a central hole 311 having a much smaller diameter than the tubular shaft 288 and the rivet 305; 284 while preventing movement of the coil spring 316 therethrough. Therefore.

The other end of the coil spring 316 abuts against the inner surface of the annular flange 309 in a manner surrounding the center hole 311 .

In this way, the positioning joint 210 is connected to the coil spring 316.
is disposed inside the tubular shaft 288 and the locating joint 21
0 has the advantage of not extending outward at all, or at least not to a large extent.

To further limit the angular movement of the one-turn plate 272, radially spaced arcuate holes 273 are formed directly opposite the radial space between the center hole 274 and the alignment hole 27B. Two directly opposing protrusions 275 formed on the inner surface of the second disk portion 224 engage inside the arcuate hole 273 to allow rotation J of the rotary plate 272! !
limit movement. In such a case, there is no need to provide limit stops 88a and 68b.

Further, the outer annular portion 272a of the rotary plate 272 is
It will be seen that the outer annular portion 272a and the inner annular portion 272b are parallel to each other, thus shown in FIG. As shown, the positioning joint 2
10, a space is formed between the outer annular portion 272a of the rotating plate 272 and the inner surface of the second disk portion 224. This space is provided to take into account the height of the protrusion 275 passing through the arcuate hole 273 in the inner annular portion 272b of the one-turn plate 272.

Furthermore, since there is such a space between the outer annular portion 272a of the rotary plate 272 and the inner surface of the second disk portion 224, the protrusion 275 can come into contact with one end of each arcuate hole 273. A spring pin 282 can be positioned in this space to rotate the rotary plate 272, typically in a clockwise direction. In this case, the circular end 284 of the spring pin 282 is attached to the second disk portion 2 by any suitable method.
24 and its hook 28B
is the opening 2 in the annular transition portion 272c between the outer annular portion 272a and the inner annular portion 272b of the rotating plate 272.
80.

In all other respects, positioning joint 210 is similar to positioning joint 10 of the embodiment of FIGS. 1-8.

Although specific preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these precise embodiments, and departs from the spirit of the present invention as defined in the claims. It will be appreciated that various modifications and variations of the present invention may be made by those skilled in the art.

[Brief explanation of drawings]

1 is a perspective view of a positioning joint for a folding ladder according to an embodiment of the present invention; FIG. 2 is a perspective view of the positioning joint of FIG. 1 seen from the opposite side; and FIG. 3 is a perspective view of the positioning joint of FIG. 3(A) is a perspective view of the locking yoke of FIG. 1; FIG. 4 is a side view of the locating joint of FIG. 1 showing the ladder in the fully collapsed position; 5 is a plan view of the locating joint of FIG. 1 showing the different positions in which the ladder can be folded and unfolded to the desired angle; FIG. 6 is a plan view of the locating joint of FIG. 7 is a cross-sectional view of the locating joint of FIG. 6 taken along line 6--6 of FIG. 1; FIG. 7 is a cross-sectional view of the locating joint of FIG. 6 showing the locking yoke in an outwardly extending position; 9 is an exploded perspective view of a positioning joint for a folding ladder according to another embodiment of the present invention; and FIG. 11 is a plan view of the push knob of the positioning joint of FIG. 9, and FIG. 11 is a cross-sectional view of the positioning joint of FIG. 9 in an assembled state. 10.210. ,,positioning joint, 12,212. ,,
First outer joint member, 14,214. ,,Second inner joint member, 20°220,,,First disk portion, 22.
222. ,, Leg portion, 24,224,,, Second disk portion, 26,228. ,,leg,2nd,228,,,spacer member,30.32.230.232. ,,width correction member, 34.35,234,235. , , vertical mounting part, 42.44.242 , 244. ,,center hole,4B,
48.246.248. ,,positioning hole,50.52.
250, 252. ,,positioning hole,54.254. ,
, third disk portion, 6B, 2H, , annular rim, 88a
, ,First (7) stopper, 88b, ,Second stopper, 68.288. ,,center hole,70.270. ,
, engagement hole, 72.272. ,, rotating plate, 74.274.
,, center hole, 76.276°0. Alignment hole, 78
．． ,, L-shaped protruding plate, 82,28200. spring pin,
88.288. , , tubular shaft, 92,292. ,, push member, 94.294. ,, connection shaft, 85.295. ,
, Side opening, 98.29B, , Large diameter head, 98,2
98. , , locking yoke, 100 , 300 . ,,connection part, 104, 304. ,,center hole,1013,3
0B, , side opening, 108 , 308 . ,,pin,!
12114, 312, 314. ,, locking pin, 11
8, 316.0. Coil spring, 272a, , ,
Outer annular portion, 272b, Inner annular portion, 272
c, , , circular transition portion, 273. ,, arcuate hole 27
5.,Protrusion, 303. ,, annular shoulder, 305. ,,
Rivet, 307, Tubular shaft, 309, Annular flange, 311. , , center hole, Fig. 11

Claims (1)

[Claims] (1) having a vertical mounting portion and first and second disk portions, each disk portion having a center hole, and the first disk portion having a first disk portion including at least one locating hole; 1 joint member, a vertical mounting part, and a third disc part having a center hole and a plurality of engagement holes arranged along the circumferential direction, the third disc part having: a second disc portion disposed between the first disc portion and the second disc portion of the first coupling member such that the at least one engagement hole is aligned with the at least one locating hole; a joint member; rotatably disposed between an inner wall of a first disc portion of the first joint member and a third disc portion of the second joint member;
a rotary plate having a central hole and at least one alignment hole formed corresponding to the engagement hole distributed along the circumferential direction in the third disk portion of the second coupling member; and inserted into the center holes of the first, second and third disk portions of the second joint member and the center hole of the rotary plate, so that the first and second joint members and the rotary plate shaft means for rotatably coupling the rotary plate together with the rotary plate; rotation limiting means for restricting the rotation of the rotary plate to a predetermined angular range between a first limit and a second limit; a first deflection means extending to the outer surface of the first disk portion to rotate the at least one of the first disk portions in the direction of the connecting portion;
at least one locating hole and selectively engageable with the at least one alignment hole of the rotating plate and the engagement hole of the third disc portion of the second coupling member. a locking yoke having two locking pins, and a connecting shaft extending to the outer surface of the second disc portion, passing through the shaft means and being coupled to the connecting portion of the locking yoke. and second deflection means for inwardly deflecting the locking yoke. 2) the second disc portion includes at least one locating hole, and the at least one locating hole of the first disc portion is aligned with the at least one locating hole of the second disc portion; A positioning joint according to claim 1. 3) The positioning joint of claim 2, wherein each of said first and second disc portions includes two directly opposite positioning holes. 4) The vertical mounting portion of the first joint member includes a first leg portion fixed to the first disc portion and a second leg portion fixed to the first disc portion.
a second leg secured to a disc portion of the disc; and spacer means coupled between the first leg and the second leg, the second leg and the spacer Claim 1, wherein the means are secured together to form a space between the first disc part and the second disc part for receiving the third disc part. Positioning fittings as described. 5) The positioning joint according to claim 4, wherein the vertical mounting portion of the first joint member includes width correction means for increasing the width thereof. 6) the vertical mounting portion of the second joint member is such that the width of the vertical mounting portion of the first joint member is equal to the width of the vertical mounting portion of the second joint member; 2. The positioning joint according to claim 1, further comprising width correction means for increasing the width of the vertical mounting portion of said second joint member. 7) The positioning joint according to claim 1, wherein the engagement holes in the third disc portion are arranged as a plurality of pairs of holes facing directly opposite each other. 8) The positioning joint of claim 7, wherein the rotating plate includes a plurality of alignment holes arranged as a plurality of pairs of directly opposing holes corresponding to a plurality of pairs of directly opposing engagement holes. 8) The positioning joint of claim 7, wherein said third disc portion includes three pairs of directly opposing engagement holes. 10) The positioning joint of claim 9, wherein said rotating plate includes three pairs of directly opposing alignment holes. 11) The positioning joint according to claim 1, wherein the center holes of the first, second, and third disk portions and the center hole of the rotary plate are arranged coaxially. 12) The rotation control means includes first and second stoppers disposed on the third disk portion so as to be spaced apart from each other in the circumferential direction, and the first stopper and the first stopper are fixed to the rotary plate. 2. The positioning joint according to claim 1, further comprising a protruding member extending between the second stopper and the second stopper. 13) The third disc portion includes an annular rim extending along a portion of the periphery of the third disc portion such that opposite ends define the first and second stoppers. The positioning joint according to claim 12. 14) The first deflection means is fixed to the vertical mounting portion of the second joint member, passes through the first and second stoppers, and is deflected into engagement with the protruding member of the rotary plate. 13. The positioning joint of claim 12 including a spring. 15) The connecting means includes a pushing member formed by a large-diameter head and the connecting shaft, and the second deflection means is configured to provide a push member between the large-diameter head and the outer surface of the second disc. The positioning joint according to claim 1, comprising a coil spring inserted into the positioning joint. 16) The connecting portion has a free end including a side opening, and the connecting portion of the locking yoke includes a center hole for receiving the free end of the connecting shaft and a side opening, and the connecting portion has a side opening. 2. The positioning joint of claim 1, further comprising pin means passing through a side opening of the connecting shaft and the connecting portion to couple the free end of the connecting shaft to the connecting portion. 17) The rotary plate has an inner annular portion oriented in a first plane, an outer annular portion oriented in a second plane parallel to the first plane, and the inner annular portion and the outer annular portion. 2. The positioning joint according to claim 1, further comprising an annular transition portion integrally joining the positioning joint. 18) The rotation limiting means includes at least one arcuate hole in the inner annular portion of the rotating plate, opposite ends defining the first and second limits, and the second disc portion. and at least one protrusion extending into the at least one arcuate hole to limit rotation of the rotating plate to the predetermined angular range. Fittings. 19) the coupling means includes a shoulder; the shaft means includes a tubular shaft and rivet means rotatably coupling the tubular shaft to the first and second coupling members; the rivet means includes a shoulder; 10. The method of claim 1, further comprising an annular flange having a central hole capable of receiving an axle, the second deflection means comprising a coiled spring disposed between the shoulder and the annular flange about the connecting axle. The positioning joint described in item 1.