JP2005061033A - Leg length adjusting device for trestle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that operation for unlocking or leg length adjustment is troublesome and takes time, it is hard to horizontally and stably install a trestle when the trestle is used in an unleveled ground such as stepped and rugged ground or inclined ground, in a trestle provided with a leg length adjustment device with collapsible legs. <P>SOLUTION: The leg length adjustment device is provided which can simultaneously unlock four collapsible legs by operating an operation lever contained in the rear side of the top plate of the trestle while holding the trestle in a standing up posture. A transmission body 15 of wires or the like is attached to the lever 23 of a locking mechanism 5 and passed through a tube 16 therefrom and passed in the flexible operation lever 8 contained in the back of the top plate 7, and further, passed through another tube 16, and connected to another lever 23 facing it. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a leg length adjusting device for a stepladder provided with a telescopic leg used on rough terrain having a step, unevenness or the like, or an inclined terrain.

  In a conventional stepladder equipped with a telescopic leg used on uneven terrain having a step or unevenness, or an inclined ground, etc., as shown in FIG. 7, each leg is composed of an upper leg member 33 and a lower leg member 34. Each leg is provided with a leg length adjusting device 35.

  In use, the lock release lever 36 of the leg length adjusting device 35 is first lifted with the fingertip to release the lock, and in this state, the lower leg member 34 is moved up and down to expand and contract the leg to obtain the required length. By releasing the lock release lever 36, the lock is applied and the required leg length can be obtained.

  However, according to the above technique, in order to unlock the leg length adjusting device and adjust the leg length, the user has to squat and operate each leg one by one, which is troublesome and takes time. There was a problem that it was difficult to make it stable.

  Therefore, this invention is a leg length adjustment that allows the user of the stepladder to unlock all four legs at the same time while holding the stepladder in a standing posture, extending to the length necessary for horizontal installation and applying the lock. It is an object to provide an apparatus.

  In order to solve the above problems, the present invention provides a stepladder including a telescopic leg comprising a hollow upper leg member and a slidable lower leg member whose upper part is fitted in the lower part of the upper leg member. A leg length adjustment device, in which the levers for unlocking the telescopic legs provided on the lower part of the upper leg member are all linked to another lever stored on the back side of the top plate with a transmission, so that the user stands The leg length adjusting device is provided with an operation lever that simultaneously unlocks and locks the four telescopic legs in a different posture.

  According to the leg length adjusting device of the present invention, the operation lever of the leg length adjusting device housed on the back side of the top plate of the stepladder can be operated while holding the stepladder in a posture in which the user is standing, and is capable of four telescopic operations. The leg can be unlocked at the same time. Therefore, the work is easier and less time-consuming than the conventional leg length adjusting device, and it is easy to install the device without wobbling horizontally.

  An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a stepladder 1 in which all four legs 2 are extendable. Each leg 2 has an upper leg member 3 and a slide in which the upper part is fitted into the lower part of the upper leg member 3. Each leg 2 is provided with a lock mechanism 5 of a leg length adjusting device for fixing the lower leg member 4 at a required length.

  The lock mechanism 5 is covered with a plastic cover 6 and fixed with an adhesive or the like in order to prevent dust and malfunction. An operation lever 8 of a leg length adjusting device is housed on the back side of the top plate 7. The pair of upper leg members 3 are arranged so as to gradually become narrower from the lower end toward the upper end side, and an end cap 9 is fitted and fixed to each lower end. A grounding block 10 is fitted and fixed to the lower end of the lower leg member 4.

  4 to 5, the upper leg member 3 is formed of a pair of a hollow base frame portion 11 having a quadrangular cross section and a C-shaped auxiliary frame portion 12 projecting against the inner surface of the base frame portion 11. It is an aluminum alloy shaped material, and is fixed to the latter frame portion 12 by rivets 14 by fitting both ends of the crosspiece 13 to the outside. A tube 16 through which a transmission body 15 such as a wire is passed is piped inside the auxiliary frame portion 12.

  The lower leg member 4 is a hollow aluminum alloy shape having a U-shaped cross section, and has a vertical groove 17 from the top to the bottom, and an aluminum alloy plate 18 is embedded with a rivet 19 at the upper end. On the opposite surface, the surface 20 is machined by cutting a continuous groove from the top to the bottom into a sawtooth shape.

  The processed surface 20 is fitted into the lower portion of the base frame portion 11 of the upper leg member 3 so as to be slidable vertically so as to face each other. The lower leg member 4 has a thickness that can be loosely fitted into the lower portion of the base frame portion 11, and is lowered by its own weight unless there is any obstacle in the downward direction and the lock is not applied. .

  In order to prevent the lower leg member 4 from being lowered too much and coming off from the base frame portion 11, an aluminum alloy plate 21 that fits inside the lower end portion of the base frame portion 11 along the recess of the vertical groove 17 of the lower leg member 4. Is fixed with a rivet 22. Therefore, even if the lower leg member 4 is lowered by its own weight, the plate 18 hits the plate 21 and the lower leg member 4 cannot be lowered beyond that position.

  FIG. 1 shows a pair of leg length adjusting devices provided on a stepladder 1. The non-expandable conductor 15 such as a wire is bonded to the lever 23 of the lock mechanism 5 by welding or the like, and is passed through the tube 16 from there and is stored in the housing 24 of the operation lever 8 stored on the back side of the top plate 7. Passed through the hole 25, passed through the operation lever 8, passed through the other hole 25, passed through the tube 16, and the lever 23 of the other locking mechanism 5 opposite to the lever 23 is free of slack. Bonded by welding etc. in the length of the state.

  In FIG. 5, the lever 23 of the lock mechanism 5 is an aluminum alloy casting, and is fixed inside the auxiliary frame 12 so as to be rotatable by a shaft 26. The lever 23 is separated from the shaft 26 into a portion where the conductor 15 is bonded and a portion of the surface 27 which is the same as the surface 20 processed on the lower leg member 4 and overlaps.

  The surface 27 passes through a hole 28 formed on the base frame portion 11 side of the auxiliary frame portion 12 and overlaps the surface 20 processed in the lower leg member 4. The torsion spring 29 is passed through the shaft 26 and presses one arm against the base frame 11 side with the inner surface of the auxiliary frame 12 and the other arm is pressed against the lever 23 and fixed rotatably.

  The surface 27 of the lever 23 is pressed against the surface 20 of the lower leg member 4 by the torsion spring 29, and the overlapping state is maintained unless the user does anything. The lower leg member 4 cannot slide up and down and is locked. It is in a hanging state.

  The lower end of the tube 16 formed of a non-stretchable material passing through the conductor 15 is sandwiched between mounting hardware 30 obtained by bending an iron plate into a U shape, and is fixed to the inside of the auxiliary frame portion 12 with a rivet 31. The upper end of the tube 16 is put out from a hole 32 formed in the auxiliary frame portion 12 and applied to the hole 25 of the fixed metal 24 of the operation lever 7.

  The operation lever 8 provided on the back of the top plate is a flexible tube, is made of an iron plate, and is stored in a length that just hits between the two holes 25 of the storage bracket 24 fixed to the back surface of the top plate 7. It is.

  That is, in FIG. 6, when the user pulls the operation lever 8, the conductor 15 in FIG. 5 slides upward and tries to lift the lever 23. When the opening force of the torsion spring 29 is lost, the lever 23 is pulled upward, the surface 27 is released from the surface 20 of the lower leg member 3 and unlocked, and the lower leg member 4 is slidable up and down.

"Effects of practical forms"
The user can pull the two operation levers 8 one at a time while lifting the top plate 7 with both hands and floating the stepladder horizontally. In addition, the two operation levers 8 can be pulled simultaneously with the other hand while lifting the top plate 7 with one hand and floating the stepladder horizontally.

  When the stepladder provided with the leg length adjusting device of the present invention is used on uneven terrain where there is a step, unevenness, etc., or sloping ground, the difference in height between the points where the four legs of the stepladder come into contact with ground is Select a position within the maximum length that can be extended.

  At that position, the user raises the four telescopic legs to their maximum and locks them up, lifts them up in a standing position, and grounds one leg at the highest point to keep it level. When the two operating levers 8 are pulled simultaneously, the lower leg members 4 of the three legs that are not grounded are lowered by their own weights, and are grounded and stopped at a length necessary to keep them horizontal. If the two operating levers 8 are released as they are, all four legs are locked, and the stepladder can be easily and stably installed horizontally.

  When contracting the telescopic legs, pull one operating lever 8 to unlock the two telescopic legs and lower the stepladder. Do the same for the other. If it is on a horizontal plane, the two operation levers 8 may be pulled down.

  Even when the ladder body of the stepladder is expanded in the rotation direction to be an integrated ladder, the length adjustment of the two legs to be grounded can be performed by pulling one operating lever on the grounding side.

It is a front view inside a stepladder. It is a side view of a stepladder. It is a perspective view of a stepladder. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is a top view of the usage example of a stepladder. It is a front view of the stepladder which shows a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepladder 2 Telescopic leg 3 Upper leg member 4 Lower leg member 5 Lock mechanism of leg length adjusting device 6 Plastic cover 7 Top plate 8 Operation lever of leg length adjusting device 9 End cap 10 Grounding block 11 Base frame part 12 of upper leg member Auxiliary frame part of upper leg member 13 Stepping bar for stepladder 14 Rivet for fixing the stepping bar 15 Non-stretchable conductor such as wire 16 Tube through transmission 15 17 Vertical groove of lower leg member 18 Plate 19 made of aluminum alloy 19 Rivet for fixing 18 20 Surface processed on lower leg member 21 Plate made of aluminum alloy 22 Rivet for fixing 21 23 Lever of lock mechanism 5 24 Storage bracket of operation lever 8 25 Hole of fixing bracket 24 26 Shaft 27 surface Same surface as 20 28 Hole through which surface 27 passes 29 Torsion spring 30 Mounting hardware 31 Rivet for fixing 30 Lower leg member 35 prior art leg adjuster 36 prior art lock release lever of the two-hole 33 the tube 16 are coming out the prior art upper leg member 34 prior art

Claims (1)

A leg length adjusting device for a stepladder comprising a telescopic leg comprising a hollow upper leg member and a slidable lower leg member whose upper part is fitted in the lower part of the upper leg member, the lower part of the upper leg member All the levers for unlocking the telescopic legs are linked to another lever that is housed on the back side of the top plate with a transmission body, and the four telescopic legs can be unlocked in a standing position by the user. A leg length adjusting device provided with an operation lever for simultaneously locking.

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