JP2854524B2 - Ladder telescopic leg fixing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder, a stepladder, or the like, which has a pair of side frames with a tread rod arranged at an appropriate interval so as to extend and retract telescopic legs at the end of each side frame. The present invention relates to a fixing device for a telescopic leg in a ladder with a telescopic leg that is mounted.

[0002]

2. Description of the Related Art In ladders or stepladders, telescopic legs are installed at the lower end of a side frame so that they can be stably used even on an installation surface such as stairs or uneven ground. JP-A-3-31700 and JP-A-5-73
For example, it is known from Japanese Patent Application Publication No.

[0003] In this type of ladder, a fixing device for an extendable leg has a rack formed on one side surface of the extendable leg, and a rack shoe is movable on a side frame side between a position where the rack shoe is engaged with the rack and a position separated from the rack. The rack shoe is provided with means for urging the rack shoe to the rack engaging position and operating means for separating the rack shoe from the rack.

Specifically, the rack shoes are movably held along an inclined guide surface approaching the rack upward, the rack shoes are urged upward by a spring, and the rack shoes are inclined downward. (See Japanese Utility Model Laid-Open Publication No. 3-31700) or a rack shoe that is movably held in the near and far directions with respect to the rack. The guide lever is provided with an operating rod that penetrates the rack shoe and the guide groove, a tiltable guide groove is formed on the operating lever that can be operated up and down, and a means for urging the operating lever is provided. (5-5
No. 3199) and a configuration similar to this are known.

[0005]

However, in any of the above-mentioned telescopic leg fixing devices, it is natural that the telescopic leg is contracted, but also when the telescopic leg is extended, the operating lever is operated to operate the rack and the rack shoe. It is necessary to perform the disengagement operation, and there is a problem that the operation is troublesome. Also,
Due to the expansion and contraction of the telescopic legs, it is inevitable that the legs of the ladder rattle, and there is a problem that the provision of the telescopic legs increases instability during use.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made in consideration of the above-described conventional problems. The object is to propose a leg fixing device.

[0007]

According to the present invention, in order to achieve the above object, the present invention is provided with the reference numerals in the drawings. In the ladder 1 having the tread rods 5 suspended at appropriate intervals, the telescopic legs 10 are attached to the ends of the side frames 4 so as to be able to move back and forth.
A locking member 2 having a rack 13 provided on one side thereof, an engaging tooth 29 for the rack 13 at one end and an operating portion 30 formed at the other end.
8 are arranged so that the engaging teeth 29 face the distal end side of the telescopic leg 10, and the engaging teeth 29 are formed on the rack 13 by a bearing portion 23 having an intermediate portion protruding from one side surface of the end of the side frame 4. Means 31 is provided for pivotally supporting between an engaging position and a position disengaging from the rack 13 and for urging the locking member 28 to rotate in a direction in which the engaging teeth 29 engage the rack 13. , Plus one telescopic leg
0 and the other side opposite to the side where the rack 13 is installed
Between the inner surfaces of the side frames 4 to be engaged with each other in a wedge shape.
18 and an engagement ridge 19 are provided .

[0008]

Further, in the second aspect, a configuration is adopted in which the tooth surface of the engagement tooth 29 on the side opposite to the distal end side of the telescopic leg 10 is an inclined surface or a curved surface.

Further, according to the third aspect, the locking member 28
Are disposed on the inner surfaces of the pair of side frames 4 and 4 facing each other and directly below the lowermost horizontal bar 5.

[0011]

According to the first aspect of the present invention, when the telescopic leg 10 is extended from the end of the side frame 4 when the telescopic leg 10 is extended, the locking member 28 having the engaging teeth 29 formed at the tip thereof. Is extended obliquely from the pivotal position of the intermediate portion toward the distal end side of the telescopic leg 10, so that the locking member 28 resists the swing urging force by the component force of the pull-out force. Rack 13 on the side
The rack 13 is easily swung in a direction away from the rack, and the engagement between the engagement teeth 29 and the rack 13 is released, and the rack 13 can be freely extended. Further, the load acting in the use state of the ladder 1 is transmitted to the telescopic leg 10 via the locking member 28 and the rack 13 because the engagement teeth 29 at one end of the locking member 28 are engaged with the rack 13. And the locking member 28 is oscillated in a direction in which one end of the locking member 28 is pressed against the rack 13 by a component force of a reaction force in a direction in which the extensible leg 10 contracts. The rack 13 engages with the locking member 28 as strongly as possible, and the telescopic leg 10 can be firmly fixed with high reliability.

[0012] In the Claim 1, because the rack 13 arrangement surface of the telescopic leg 10 is provided with a leg restraining groove 18 and the engaging protrusion 19 that engages the wedge to each other on the other side, of the When the locking member 28 is strongly pressed against the rack 13 according to the load, the extensible leg 10 is pressed toward the inner surface of the side frame 4 and the leg restraining groove 18 and the engaging ridge 19 are strongly engaged in a wedge shape. As a result, rattling of the telescopic leg 10 is reliably prevented, and the ladder 1 can be used with good stability while having the telescopic leg 10.

According to the second aspect, the locking member 28 can be smoothly swung in the direction away from the rack 13 when the telescopic leg 10 is pulled out, so that the pull-out operation of the telescopic leg 10 can be easily performed without great resistance. I can do it.

According to the third aspect of the present invention, since the locking member is disposed immediately below the lowermost horizontal rod 5, a foot or the like hits the operating portion 30 of the locking member during operation or the like, and It is possible to eliminate the possibility that the fixing is unexpectedly released.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the ladder of the present invention is applied to a stepladder will be described below with reference to FIGS.

FIGS. 1 and 2 show the overall configuration of a stepladder, in which a pair of ladders 1 and 1 are arranged opposite to each other, and
An upper end portion 1 is pivotally connected to a pin 3 via brackets 2 and 2.

As shown in FIGS. 2 to 4, each ladder 1 is composed of a pair of side frames 4, 4 and tread rods 5 arranged between the side frames 4, 4 at appropriate intervals in the vertical direction. Each side frame 4 is formed of an extruded aluminum member having a substantially U-shaped cross section, and the tread rod 5 is formed of an extruded rectangular aluminum tube member. The pair of side frames 4, 4 are disposed such that their opening portions having a U-shaped cross section are opposed to each other, and at the upper part of these side frames 4, as shown in FIG. It is fitted and fixed with rivets 6.

In the lower part of the side frame 4, as shown in FIG. 4, a sub-side frame member having a substantially U-shaped cross section is formed so that the opening of the side frame 4 is closed to form a side frame having a rectangular cross section. 7 are fitted and integrally connected to the side frame 4 by rivets 8.
On both side edges of the sub-side frame member 7, protruding strips 9 are provided so as to protrude in the direction opposite to the side frame 4, and the ends of the tread rods 5 are welded.

An extensible leg 10 made of an extruded aluminum material is inserted into the lower part of the side frame 4 inside the rectangular cross section so as to be freely retractable from the lower end of the side frame 4. The telescopic leg 10 has a substantially rectangular overall cross-sectional shape, and L-shaped ridges 11 having an L-shaped cross-section are protruded from both side edges of one side surface of the side frames 4 and 4 so as to form a dovetail-shaped rack. A holding part 12 is formed, and a rack 13 is mounted. A reinforcing ridge 14 is provided outside the L-shaped ridge 11.

The rack 13 is, as shown in FIGS.
A plurality of rack pieces 15 of an appropriate length are arranged in series, and these rack pieces 15 are sequentially inserted into the rack holding portion 12, and fixed pieces 16 are inserted and arranged at both ends thereof, and are expanded and contracted by rivets 17. It is configured to be fixed to one side surface of the leg 10. When a plurality of rack pieces 15 are used as described above, a plate-shaped body with rack teeth having a width corresponding to the length of the rack pieces 15 is extruded, and cut into pieces each corresponding to the width of the rack pieces 15. A large number of rack pieces 15 can be easily and inexpensively manufactured, and by arranging them in series, a rack 13 having an arbitrary length can be formed.
The tooth surfaces of the rack 13 are anodized to improve wear resistance.

On the other side of the telescopic leg 10 opposite to the side on which the rack holding portion 12 is formed, as shown in FIGS. 4, 5 and 6, both side surfaces 18a face outward. A leg restraining groove 18 that spreads in a letter shape is formed. Meanwhile, side frame 4
On the inner surface facing the other side of the telescopic leg 10 at the lower end of the
An engaging projection 19 of a suitable length having a substantially M-shaped cross-section and a wedge-like overall shape, which is fitted and engaged with the leg restraining groove 18, is fixed by a rivet 20. Note that both side surfaces 18 of these leg restraining grooves 18 are provided.
An alumite treatment is applied to the engaging surface between the a and the engaging ridge 19 to improve wear resistance. As a result, when the telescopic leg 10 is pressed toward the inner side surface of the side frame 4, the leg restraining groove 17 and the engaging ridge 19 are engaged with each other in a wedge shape, so that the telescopic leg 10 is loosened on the side frame 4. It will be fixed without sticking. Reinforcing ridges 21 are provided on both sides of the other side surface of the telescopic leg 10 to protrude outward, and the reinforcing ridges 14 and 21 improve cross-sectional performance of the telescopic leg 10.

As shown in FIGS. 5 and 6, a pair of bearings 23 are provided at the lower ends of the opposing side surfaces of the side frame 4 at appropriate intervals in parallel in place of the auxiliary side frame member 7. The provided bearing support member 22 is fixed. This bearing support member 2
2 has a substantially U-shaped cross section similar to the sub-side frame member 7 except for the bearing portion 23, is fitted to the lower end of the side frame 4, and is integrally connected to the side frame 4 with rivets 24. Have been. On both side edges of the bearing support member 22, engagement ridges 25 are provided so as to protrude in a direction facing the side frame 4, and a cover 26 for covering the bearing portion 23 is mounted.

A pivot shaft 27 is inserted through the pair of bearing portions 23, and an intermediate portion of a lever-shaped locking member 28 disposed between the pair of bearing portions 23, 23 is connected to the pivot shaft 27. It is pivotally supported. One end of the locking member 28 extending toward the distal end (lower side) of the telescopic leg 10 is connected to the bearing support member 22.
The rack 22 extends toward the rack 13 through the opening 22a formed therein. At the other end of the locking member 28, an operation portion 30 protruding outside from an opening 26a formed in the cover 26 is formed. The tooth shape of the engaging teeth 29 is not a rectangular tooth, and only the tooth surface 29a on the opposite side to the distal end side of the telescopic leg 10 is an inclined surface or a curved surface. Further, the tooth surfaces of the engaging teeth 29 are anodized to improve wear resistance. A helical spring 31 is wound around the pivot shaft 27, one end of which is engaged with the bearing support member 22, the other end of which is engaged with the operating portion 30, and the engaging teeth 29 are pressed against the rack 13. The stop member 28 is urged to swing.

The lowermost tread rod 5 is fixed to the lower end of the sub-side frame member 7, so that the locking member 28 is disposed immediately below the lowermost tread rod 5. Reference numeral 32 denotes an upper cover made of a synthetic resin for closing an upper end opening of the cover 26,
Reference numeral 33 denotes a synthetic resin lower end cover that closes the lower end surfaces of the cover 26, the bearing support member 22, and the side frame 4. Reference numeral 34 denotes a non-slip member attached to the lower end of the telescopic leg 10.

In the above configuration, as shown by the phantom line in FIG. 1, when the stepladder is erected on an uneven installation surface such as a stair, the telescopic leg 10 below the required side frame 4 is required in accordance with the unevenness. The stepladder can be stably erected by extending it by an amount, and the operation can be safely performed by a simple operation without forming a horizontal installation surface using a table or a scaffold plate.

Moreover, in order to extend the telescopic legs 10 of the required side frame 4 by a required amount in this way, simply pull out the telescopic legs 10 from the end of the side frame 4 and no other operation is required. And can be extended very easily. That is, one end side of the locking member 28 having the engaging teeth 29 formed at the distal end extends obliquely toward the distal end side of the telescopic leg 10 from the intermediate portion pivotally supported by the pivot shaft 27. So Figure 7
When the telescopic leg 10 is pulled out as shown by an arrow a in FIG. 5A, the locking member 28 is partially driven by the pulling force against the urging force of the helical spring 31 as shown by an arrow b. The side is easily swung in the direction away from the rack 13, the engagement between the engaging teeth 29 and the rack 13 is released, and the side can be freely extended. Further, since the tooth shape of the engaging teeth 29 is not rectangular, only the tooth surface 29a opposite to the distal end side of the telescopic leg 10 is an inclined surface or a curved surface. Can be smoothly swung in the direction away from the rack 13, and the operation of pulling out the extendable leg 10 can be easily performed without great resistance.

In the use state of the stepladder, a load acts on the side frame 4. However, since the engagement teeth 29 at one end of the locking member 28 on the side frame 4 side are engaged with the rack 13, the load is applied. It is transmitted to the telescopic leg 10 via the locking member 28 and the rack 13 and is reliably supported on the installation surface. At this time, the telescopic legs 10
A reaction force acts as shown by a white arrow c in FIG. Assuming that the magnitude of this reaction force is F, the acting position of the reaction force at one end of the locking member 28 is A, and the axis of the pivot shaft 27 is O, the reaction force F is as shown in FIG. It is decomposed into a OA compressive force C acting on the locking member 28 and a swing biasing force R pressing one end of the locking member 28 toward the rack 13 side. As a result, the engagement teeth 29 at one end of the locking member 21 are pressed against the rack 13 when a load is applied, and the rack 13 and the engagement teeth 29 are more strongly engaged as the load is increased. The leg 10 can be firmly fixed with high reliability.

Further, since the leg restraining grooves 18 and the engaging ridges 19 which are fitted and engaged with each other in a wedge shape are provided on the side of the telescopic legs 10 opposite to the surface on which the rack 13 is provided, as described above, the load can be reduced as described above. When the swing urging force R for pressing the engaging teeth 29 strongly against the rack 13 acts accordingly, as shown in FIG. 7C, the pressing force which is a component force of the swing urging force R perpendicular to the rack 13. At P, the telescopic leg 10 is pressed toward the inner surface of the side frame 4, and the leg restraining groove 18 and the engaging ridge 19 are strongly engaged in a wedge shape. As a result, not only in the pressing direction but also in a direction perpendicular thereto. Again, the play of the telescopic leg 10 is reliably prevented. Therefore, the ladder can be used with good stability while having the telescopic legs 10.

Further, since the operating portion 30 protruding from the cover 26 of the locking member 28 is disposed immediately below the lowermost horizontal rod 5, a foot or the like hits the operating portion 30 during work or the like to fix the extendable leg 10. There is no danger of accidental release.

When the telescopic leg 10 is contracted after the use of the stepladder, the operating portion 30 of the locking member 28 is pressed and the locking member 2 is pressed.
8 is disengaged from the side frame 4 by swinging the rack 8 against the urging force of the helical spring 31 to release the engagement between the engagement teeth 29 at one end of the locking member 28 and the rack 13. It can be retracted and can be inserted into the lower part of the side frame 4 and contracted.

In the above embodiment, the leg restraining groove 18 is recessed in the other side surface of the telescopic leg 10, and the engaging ridge 19 is fixed to the inner surface of the lower end of the side frame 4 with the rivet 20. Telescopic leg 1
The cross-sectional shape of the side frame 4 is substantially rectangular, and the engaging ridge 19 is fixed to a required portion at the lower end of the side frame 4 to reduce the cost. 18 may be formed, and the engaging leg 19 may be formed so as to protrude on the other side surface of the telescopic leg 10. However, in that case, the cross-sectional shape of the telescopic leg 10 cannot be made substantially rectangular.

[0032]

According to the first aspect of the present invention, when the telescopic leg is pulled out from the end of the side frame when the telescopic leg is extended, one end of the locking member swings in a direction away from the rack. Since the locking of the locking teeth and the rack is released, the locking member can be extended freely, and when the telescopic leg tries to contract while using the ladder, one end of the locking member faces the rack due to the component force of the reaction force against the load. As the load is increased, the rack and the locking member are more strongly engaged with each other, so that the rack can be firmly fixed with high reliability.

Further, according to claim 1, since the provided foot restraining groove engaging projection that engages the wedge to each other on the opposite side to the rack arrangement surface of the telescopic leg, according to the load as described above When the locking member is strongly pressed against the rack, the extensible legs are pressed toward the inner surface of the side frame, and the leg restraining grooves and the engaging ridges are strongly engaged in a wedge shape, and as a result, the play of the extensible legs is ensured. Is prevented by
The ladder can be used with good stability while having the telescopic legs.

According to the second aspect , when the extension leg is pulled out, the locking member can be smoothly swung in the direction away from the rack, and the extension leg can be easily pulled out without great resistance.

According to the third aspect of the present invention , since the locking member is disposed immediately below the lowermost horizontal bar, a foot or the like hits the operating portion of the locking member during work or the like, and the fixing of the telescopic leg is released unexpectedly. Can be eliminated.

[Brief description of the drawings]

FIG. 1 is an overall front view of an embodiment in which the present invention is applied to a stepladder.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 1;

FIG. 5 is a cross-sectional view of the telescopic leg fixing device according to the embodiment, which is a cross-sectional plan view taken along line DD of FIG. 1;

FIG. 6 is a longitudinal sectional view of the telescopic leg fixing device in the embodiment, and is a longitudinal sectional side view taken along line EE of FIG. 1;

FIG. 7 is an operation explanatory view of the telescopic leg fixing device in the embodiment.

FIG. 8 is a partial perspective view showing a rack mounted state in the embodiment.

FIG. 9 is a vertical cross-sectional view showing a rack mounted state in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ladder 4 Side frame 10 Telescopic leg 13 Rack 18 Leg restraining groove 19 Engagement ridge 23 Bearing part 28 Locking member 29 Engaging tooth 30 Operation part 31 Helical spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-21173 (JP, A) JP-A-7-293165 (JP, A) Japanese Utility Model Application 58-20100 (JP, U) Japanese Utility Model Application Hei 5- 77500 (JP, U) Jiko 36-11475 (JP, Y1) (58) Fields investigated (Int. Cl. ⁶ , DB name) E06C 1/12 E06C 7/44 E06C 1/30 E06C 7/06

Claims (3)

(57) [Claims] 1. A ladder comprising a pair of side frames with a tread bar laid horizontally at appropriate intervals, with telescopic legs attached to the ends of each side frame so as to be freely retractable and a rack on one side of the telescopic legs. A locking member having an engaging tooth for the rack at one end and an operating portion formed at the other end is disposed so that the engaging tooth is directed toward the distal end of the telescopic leg, and an intermediate portion thereof is disposed at one end of the side frame. A bearing portion protruding from the side surface pivotally pivots between a position where the engaging teeth engage with the rack and a position where the engaging teeth are disengaged from the rack, and engages in a direction in which the engaging teeth engage with the rack. A means for rotating and urging the stop member is provided , and the other side of the telescopic leg opposite to the rack arrangement surface is provided .
Wedge-shaped engagement between the inner surfaces of the side frames facing this
A telescopic leg fixing device for a ladder, comprising a leg restraining groove and an engaging ridge . 2. The tooth surface of the engaging tooth opposite to the distal end of the telescopic leg.
2. The telescopic leg fixing device for a ladder according to claim 1 , wherein the inclined surface is a curved surface or a curved surface . 3. A locking member which opposes a pair of side frames.
The telescopic leg fixing device for a ladder according to claim 1, wherein the ladder is disposed at a position directly below the lowermost horizontal rod on the inner surface .