JP4332884B2 - stepladder - Google Patents

Description

  The present invention relates to a stepladder in which a leg portion is easily adapted to undulations on the ground.

  General-purpose stepladders configured to handle both high and low steps are heavy and costly. If there is enough time for a small amount of work, a multi-purpose type that can be used as a stepladder or a ladder may be used. The efficiency increases with a large number of items. In the work site, the more tools by application, the higher the efficiency.

  A stepladder is known which has a pair of ladder sections and is composed of four legs. The ladder portion includes a pair of opposing side bar members and a crosspiece that is coupled between the upper end portions and intermediate positions of the pair of side bar members.

  It is known that if it is placed on the ground, it will stabilize if it is placed at 3 points. However, in the case of a stepladder, since it has four legs, when there is a ground undulation, three of the four legs are in contact with each other, and one of the legs is not in contact with the ground. In this case, if the weight is moved on the stepladder and the center of gravity deviates from the range of the triangle with the grounding point of the three feet that are in contact with the ground, and the weight is applied to the feet that are not in contact, the stepladder staggers. Become unstable.

  On the other hand, Patent Document 1 discloses that a cylinder and a piston are formed on four foot tips of a stepladder. Each cylinder is connected via a hose and a cross cock, and when one of the paired piston rods retracts, the other piston rod advances. In this state, the piston can be fixedly held by switching the cross cock to prevent the oil from flowing.

Further, instead of the cylinder and the piston, a transmission body is provided and connected at the tip of a pair of legs, and the conductor is slid and guided by curved guides that are passed from both sides of the ladder part. Yes. In addition, a lock mechanism for preventing the slide displacement of the adjusting leg is provided on the column facing the slide area of the leg. The transmission body is composed of a strip-shaped spring plate formed of a metal or plastic material, or is composed of a closely wound spring or a spring wound shaft body formed of a flexible shaft.
Japanese Utility Model Publication No. 1-150900 Japanese Patent Laid-Open No. 11-30087

  An object of the present invention is to provide a stepladder that can be quickly and stably placed regardless of the undulation state of the ground or the like.

  On the floor, you can't see it with your eyes, but if you set up a stepladder, there are a lot of backlashes. In such a case, the present invention has been developed to cope with a convenient stepladder, particularly a low step.

  The stepladder of the present invention is a stepladder in which one end of a pair of ladder portions is connected, and at least one ladder portion includes a pair of guides, a step rail fixedly passed between the upper ends of the pair of guides, and a pair of guides And a pair of legs guided to be slidable in the length direction thereof, and a shaft fixedly attached to the step rail, and extending in a direction perpendicular to a plane formed by the step rail and the pair of guides. A shaft, a pivot member extending left and right with the shaft as a fulcrum, a means for causing one end of the pair of legs to slide on one end of the pivot member, and the other end of the pivot member on the pair of legs Means for causing the other side to act, and a lock mechanism for locking the crosspiece and the relative variation of the rotating member.

  According to the present invention, it can be quickly and stably placed on the ground regardless of the undulation state.

In particular, a shaft fixedly attached to the crosspiece serves as a fulcrum, and the sliding leg is supported like a seesaw so that it can be quickly placed.
Therefore, it is superior in terms of the overall cost and weight of the stepladder as compared with the adjustment leg using the hydraulic cylinder of Patent Document 1.

  In addition, the transmission body of Patent Document 2 that slides the curved guide needs to be loosely placed due to friction between the curved guide and the transmission body, and the present invention is superior in quickness to placement. It is. In addition, the weight of the stepladder or its load is applied to the curved guide, and it is necessary to increase the thickness of the curved guide itself so as to increase the weight. Conversely, if the wall thickness is reduced, the transmission body is deformed and the transmission body is difficult to slide.

  In Patent Document 2, the lock mechanism fixes the leg by frictional force after being fixed, but the fixation by frictional force is good for the purpose of stopping the brake gradually, but momentarily like a stepladder. It is weak for applications where force is applied. Furthermore, the lock mechanism protrudes outside the stepladder. In this case, there is a possibility of contact when a person on the vehicle falls.

  FIG. 1 is a perspective view of a stepladder 1 according to this embodiment. The stepladder 1 has two ladder bodies 10 and 20 coupled at their upper ends so as to be rotatable about the shaft 2 and is in a folded state and a used state depending on the opening angle. FIG. 1 shows a state that contributes to the use, and the opening angle is limited by the hook 12.

  In the ladder body 10, a pair of side bar members 11 are fixedly coupled to the crosspiece 13 via a connecting plate 15 at the upper end portion. Further, the side bar member 11 is fixedly coupled to the intermediate portion by a crosspiece 14.

FIG. 2 shows a front view and a side view of the ladder body 20. In the ladder body 20, a pair of guides 21 extending in the vertical direction are fixedly coupled to the crosspiece 23 via a connecting plate 25 at an upper portion thereof. Further, the guide 21 is coupled by a foot cross 24 near the lower end thereof.
The guide 21 is a member having a U-shaped cross section, and a groove is provided in the length direction on the inside thereof. The guide 21 is slidably guided in the length direction by the rail 35 on each leg 26. A connecting member 28 is rotatably connected to the upper end of the leg 26 via a shaft 29, and the connecting member 28 is further connected to a rotating member 31 so as to be rotatable via a shaft 30. As shown in the drawing, the rotating member 31 is rotatably connected to the connecting member 28 in the vicinity of both ends.

  On the other hand, a back plate 34 is attached to the step rail 23 in parallel to a plane formed by the step rail 23 and the pair of guides 21. The back plate 34 is further provided with a shaft 32 that protrudes vertically below the center of the crosspiece 23. The shaft 31 is a shaft that is fixedly provided with respect to the step rail 23. The rotating member 31 is supported by a shaft 32 at the center of its length and is rotatable.

  The ladder body 20 is further provided with a lock member 33 and a lock piece 34, which will be described separately.

  FIG. 3 illustrates the operation of the ladder body 20 according to the present embodiment.

  When the ground contact surfaces of the left and right legs are flat as indicated by A in the figure, the pair of legs 26 are left and right with respect to a plane perpendicular to the ground passing through the shaft 32 as shown in FIG. Symmetric positional relationship.

  On the other hand, when there is an obstacle under the left leg as shown in B in the figure, the left leg 26 rides on it as shown in A in the figure. At this time, through the connecting member 28, the rotating member 31 operates like a seesaw around the shaft 32 as shown in FIG. The pair of legs 26 is held in parallel by the guide 21.

  In the ladder body 10 (not shown), the two side bar members 11 are grounded, so that the horizontal position of the step 13 is determined. On the other hand, the load F on the ladder body 20 side is applied to the shaft 32, and the horizontal position of the step rail 23 is defined by the installation relationship of the two side bar members 11.

  As long as these weights are applied to the shaft 32, the posture of the step rail 23 is defined by the installation relationship of the two side bar members 11, as described above. For example, when a person rides and a weight f is applied to the left side of the foot cross 23 and the center of weight is shifted from the shaft 32, the horizontal position of the foot cross 23 changes.

  Therefore, in this embodiment, as shown in FIG. 2, a lock mechanism is provided by the lock member 33 and the locked piece 34. As shown in FIG. 3, once this function is established, the relative positions of the rotating member 31, the connecting member 28, and the legs 26 with respect to the uneven surface are determined with respect to the tram 23. It is for locking relationships.

FIG. 4 shows details of the lock member 33 as viewed from above. The lock member 33 is installed on the rotation member 31, and guides the lever 51, the spring member 52, the shaft 53, the lock piece 54, the lever holding piece 56, and the lock piece 54 in the length direction of the rotation member. It consists of a guide member 57.
The shaft 53 is a shaft provided on the rotating member 33, and holds the lever 51 rotatably. One end of the pair of spring members 52 is rotatably installed in a hole equidistant from the shaft 53 of the lever 51, and a lock piece 54 is provided on the other end.

  When the lever 51 is rotated clockwise as shown in the figure, the spring member 52 is pushed away in the direction away from the shaft 53 (direction E), and the position of the lock piece 54 is moved outward.

  As shown in FIG. 2, on the outside of the lock piece 54, there is provided a locked piece 34 extending downward from the crosspiece. When the lever 51 is moved clockwise, the lock piece 54 comes into contact with the locked piece and is further urged outward by the spring member 52 to be firmly fixed. Since the lock pieces 54 on both sides are similarly fixed to the locked pieces 34 on both sides, the lock pieces 54 are fixed symmetrically, so that stability is improved. Further, the lock piece 54 and the locked piece are present at positions away from the shaft 32 serving as a fulcrum. For this reason, the action point to be locked and the fulcrum are separated, and the stability of the rotating member 31 is further enhanced.

  The rotating member 31 is provided with a holding piece 56 for preventing the lever 51 from returning, and the lever 51 is accommodated in the rotating member 31 substantially in parallel during normal use. Since the position of the lever 51 is the position of the rotating member 31 and the position of the stepladder is high, the workability of the lock is good.

  It should be noted that in order to unlock the tread bar 23 and the rotating member 31, the lever 51 can be detached from the holding piece 56 by pulling counterclockwise.

  FIG. 5 shows details of the lock piece 54 and the locked piece 34. The locked piece 34 is a curved cylindrical rod-shaped member, and is threaded. The lock piece 54 is provided with a female screw thread so as to be fitted into a screw thread provided on the locked piece 34. The curve of the locked piece 34 is a circular arc centered on the shaft 34. A thread guide 58 is provided on the extension of the lowermost thread provided on the lock piece 54.

  FIG. 6 is a view of the lock piece 54 as viewed from below, and shows a state in which the lock piece 54 is engaged with the locked piece 34. When the lock piece 54 reaches the locked state, first, the thread guide 58 moves in the direction of E along the outer periphery of the lock piece 34. As a result, the thread provided with the lock piece 54 and the thread of the locked piece 34 are fitted to each other without colliding with each other.

  In the above embodiment, the rotating member 31 is connected via the two members of the leg 26 and the connecting member 28. This is because the position of the shaft 30 is not provided immediately above the leg 26. ing. This is for the purpose of avoiding contact with the locked member 34 when the rotating member 31 is rotated.

  If the position of the shaft 30 is provided immediately above the leg 26, it is not necessary to divide the shaft 30 into two members, the leg 26 and the connecting member 28.

  FIG. 7 shows a schematic diagram in which the leg 26 and the rotating member 23 are directly connected by a shaft 30 '. The guide 21 is omitted in the figure for simplification. When the ground B is not as flat as the ground A, for example, the left leg is lifted, but it is understood that the foot cross 23 can be positioned horizontally around the axis 32 as in the previous embodiment. The That is, the posture is defined by the horizontal position of the ladder 13 of the ladder body 10 (not shown).

  FIG. 8 shows an embodiment based on FIG. In the stepladder of this embodiment, the leg 26 and the rotating member 23 are directly connected by a shaft 30 '. In this embodiment, the leg 26 slides in the vertical direction, and the rotating member 23 rotates. Therefore, the distance between the shaft 32 and the shaft 30 ′ varies depending on the movement of the rotating member 23. Will do. In order to absorb this fluctuation, the rotating member 23 has an oval receiving hole through which the shaft 30 'can move.

  In the lock mechanism of this embodiment, as shown in FIG. 9, the lock plate 60 is installed on the crosspiece 23 via a hinge 65. When the position of the leg 26 is determined, the lock plate 60 is tilted downward, the lock piece 63 is engaged with the locked piece 64, and the leg 26 and the rotating member 31 are fixed with respect to the tread bar 23.

  Conversely, in the above example, the example in which the connecting member is omitted is shown, but a large number of connecting members may be inserted between the leg and the rotating member. However, in this case, it should be noted that instability increases due to play around each axis.

  In the above-described embodiment, the ladder unit 10 is shown in which the side bar member and the step bar are fixedly connected. However, the ladder unit 10 may be configured similarly to the ladder unit 20. The lock mechanism of both ladder parts is set to the open state, and the lock mechanism is set to the locked state in a state where the step rail is pressed horizontally by hand. In this case, the mechanism is complicated as compared with the above-described embodiment, and it takes a little time and effort, but there is an advantage that the crosspiece can be set horizontally.

  In the above-described embodiment, the pair of ladder portions is provided with a shaft at the upper end thereof so as to be rotatable, and can be folded or used as an upper body, but may be fixed.

Perspective view of stepladder 1 according to this embodiment Front view and side view of ladder body 20 The figure explaining operation | movement of the ladder body 20 by a present Example Top view of lock member 33 Detailed view of locked piece 54 and locked piece 34 Bottom view of lock piece 54 Schematic diagram of another embodiment The figure which shows another Example Side view of a locking mechanism according to another embodiment

Explanation of symbols

1 Stepladder
10,20
21 Guide
23 tram
26 legs
31 Rotating member
33 Locking member
34 Locked piece

Claims (3)

In a stepladder in which one end of a pair of ladder portions is connected, one ladder portion includes a pair of left and right side bar members, and a first traverse fixedly passed between upper ends of the pair of side bar members. The other ladder part is slidable in the longitudinal direction by the pair of left and right guides, the second step rail fixedly passed between the upper ends of the pair of guides, and the pair of guides. a pair of legs which is guided in, a shaft provided fixedly to said second踏桟, a shaft extending in a plane in which the second踏桟a pair of guide forms a vertical direction A rotating member extending left and right with the shaft as a fulcrum; first means for causing one end of the pair of legs to slide on one end of the rotating member; and the other end of the rotating member A second means for causing the other side of the pair of legs to slide, and a lock mechanism for locking a relative variation of the traverse and the rotating member ;
The locking mechanism is provided on the second side of the shaft on the left and right sides of the shaft, is curved into an arc centered on the shaft, and is a locked piece in which a thread is engraved.
A lever provided on the rotating member side;
A locking piece engraved with a female thread that engages with the thread of the locked piece provided on the left and right of the shaft;
The lock piece provided on the left and right of the shaft is moved in the length direction of the rotating member in conjunction with the operation of the lever to change from the non-contact state to the locked piece, and further to the left and right of the lock piece. A stepladder having a spring member biased outward. 2. The left and right lock pieces according to claim 1, wherein the left and right lock pieces have a thread guide on the extension of the engraved female thread, and when the lock pieces come into contact with the corresponding lock pieces, the outer periphery of the lock pieces The stepladder is characterized in that it has a screw thread that moves to the left and right sides and engages with each other.   In Claim 1, the first means includes a first connecting member, and is provided rotatably on the one leg and one end of the rotating member via respective shafts. The step 2 has a second connecting member, and is provided on the other leg and the other end of the rotating member so as to be rotatable via a shaft, respectively.

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