JP5240644B2 - Extension ladder for stepladder - Google Patents

Description

  The present invention relates to an extended ladder of a stepladder (hereinafter simply referred to as an extended ladder), which can be expanded into a ladder with a simple operation by extending the ladder-like stepladder. It relates to an extension ladder that can stabilize the ladder.

  Since the structure and intended use of the ladder and stepladder have been well known for a long time, further detailed explanation is omitted here.

Japanese Patent Application No. 2011-006439

  When using a stepladder with a ladder and legs expanded as a ladder by leaning on a utility pole or tree, the step bar at the top of the ladder and the utility pole are in point contact, so in places where the scaffolding is bad It is very dangerous to slip or slip if the center of gravity changes.

  Therefore, the applicant of the present invention can extend the ladder or the ladder of the stepladder that has been expanded into a ladder shape with a simple operation and can stabilize the ladder, using the invention described in Patent Document 1 above. Proposed a ladder.

  The extension ladder is a ladder-like base body in which a pair of vertical rods are connected by a plurality of horizontal step bars, and an L-shaped member integrally coupled to the lowermost step bar of the base body, and is parallel to the base body. At least one hanging body with a front hanging part protruding to the front surface side, and the uppermost part of the base body are mounted at a position parallel to the step bar, and the projection shape on the plane perpendicular to the vertical plane of the base body is on the back side An open V-shaped engagement rod, and a fixing mechanism for removably connecting a base body having a hook body engaged with an arbitrary step bar of a ladder or a stepladder from the back side to the ladder or a stepladder. The mechanism consists of a vertical shaft above the hook or a vertical shaft to the base that is pivotably supported in the vicinity of the vertical shaft above the hook and an end on the surface side of this shaft. An arm parallel to the base body mounted on the section; A screw rod parallel to the support shaft fixed to the free end of the arm, a pressing body made of an elastic body screwed coaxially with the screw rod, and an end portion on the surface side of the screw rod An operation lever parallel to the arm, and a base engaged with the back side of the ladder or stepladder through the hooking body is brought into contact with the back side of the ladder or stepladder, and then the operation lever penetrated to the front side is provided. The hooking body and the pressing body are expanded in the vertical direction by rotating the pressing body through pressure and bringing the pressing body into pressure contact with the lower surface of the ladder or stepladder step bar.

  The extension ladder described in Patent Document 1 is rational because the upper end of the ladder does not wobble when it is stood on a standing tree or a utility pole in use, and the load is not applied to the fixing mechanism. However, the extension ladder may come off when the upper end of the extension ladder is separated from the ladder or stepladder.

  This disengagement of the extension ladder occurs only when transporting an extension ladder attached to a stepladder or the like, and during use it receives a force in the direction in which the two are in close contact with each other, so there is no problem in safety, but care is taken in transport. There is still room for improvement, such as the fact that it has to be used slightly impairs usability.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an extension ladder in which when an extension ladder is assembled to a stepladder, the two are securely coupled and not separated.

  In order to achieve the above object, the invention described in claim 1 is integrally coupled to a ladder-like base body in which a pair of vertical rods are connected by a plurality of horizontal step bars, and a step bar at the lowest stage of the base body. An L-shaped member having a cross-section, which is mounted on the top of the base at a position parallel to the step bar, and is attached to the top of the base at a position parallel to the step bar. A V-shaped engagement rod whose projection shape with respect to a plane perpendicular to the rod is opened on the back surface side, and a fixing mechanism that removably connects a base body that is hooked on an arbitrary step bar of the stepladder from the back surface side to the stepladder. The fixing mechanism includes a pair of left and right support shafts that are substantially perpendicular to the vertical shaft of the base above the hook body, or a base that is rotatably supported in the vicinity of the vertical hook in the horizontal direction, and The base is supported on the support shaft so that the base end is rotatable. A pair of left and right operating levers that extend in parallel and have a fixed piece and a protrusion provided on the back side, and a base that is engaged with the back side of the stepladder via the hooking body. After making contact with the back surface, the operating levers that have penetrated to the surface side of the stepladder in a manner in which the free ends face each other are rotated upward, respectively, and the fixed piece is placed at the top dead center position orthogonal to the step bar of the stepladder. The lower side of the step bar of the stepladder was pushed up, the protrusion was pressed against the surface of the step bar, and each control lever was fixed with a stopper at an angular position slightly turned outward from the top dead center position. It is characterized by.

  The invention according to claim 2 is characterized in that the support shaft of the operation lever is inclined slightly outward in a plane including the support shaft and perpendicular to the base body.

  The extension ladder according to the present invention configured as described above is provided on the front side of the rear ladder in which the hook is hooked on the step bar of an arbitrary height from the back side of the ladder, and then the base is brought close to the back side of the ladder. The extension ladder can be installed very easily because it can be installed on the ladder by operating the fixed mechanism.

  In addition, since a V-shaped engagement rod whose projection shape with respect to a plane perpendicular to the vertical rod is open on the back side is attached to the uppermost portion of the base, the V-shape of the engagement rod is engaged with a utility pole, a tree, or the like. This makes the ladder much more stable and improves usability.

  Furthermore, under normal use conditions, the static load applied to the fixing mechanism is zero, and the load in the length direction of the ladder applied to the extension ladder is carried by the hooking body.

  The hook that carries the load is strong because of its simple structure, and thus the extension ladder can maintain its function for a long time.

  In addition, according to the second aspect of the present invention, since the support shaft is slightly inclined outward, the protrusion on the back surface of the support lever is swung close to the surface of the step bar of the stepladder due to the rotation of the operation lever. However, there are various effects such as that the stepladder is pressed against the surface of the step bar and the connection between the stepladder and the extension ladder is strengthened.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of an extension ladder according to an embodiment of the present invention, which is unfolded and joined to a stepladder as a ladder, in which a part of a step bar of the extension ladder is not shown for the sake of clarity. The expanded partial sectional view by the II-II line of FIG. The expanded partial sectional view by the III-III line of FIG. The partial cross section top view by the IV-IV line of FIG. The expanded side view by the VV line | wire of FIG. The top view of an extension ladder. The enlarged front view of a fixing mechanism. The partial cross section enlarged side view of a fixing mechanism. It is a partial cross-sectional enlarged plan view of the support shaft portion of the fixing mechanism, and the bending angle of the metal fitting is exaggerated. The side view of FIG.

  A hook is attached to the lower end of the base, and a V-shaped engagement hook having a projected shape with respect to a plane perpendicular to the vertical hook of the base is opened on the back side, and a ladder or a stepladder is placed via the hook. After the base engaged with the back side of the ladder is brought into contact with the back side of the ladder or stepladder, the operation lever of the fixing mechanism that has penetrated to the front side is rotated so as to intersect the step bar of the stepladder, and the back side of the operation bar Since the protrusion protruding on the side is pressed against the step bar of the stepladder, not only can the extension ladder be easily and easily attached to the stepladder, but also the connection between the extension ladder and the stepladder becomes strong and transported. Handling becomes convenient at the time, and further, by engaging the engaging rod with the utility pole or the like, the extension ladder and the stepladder can be stably leaned against the utility pole or the like, so that the ease of use of the ladder is remarkably improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes the entire base of the extension ladder. The base 1 is a ladder in which a pair of vertical rods 2 and 2 are connected by a plurality of horizontal (three in the illustrated embodiment) step bars 3 and 3. It is shaped into a shape.

  This configuration is the same in the stepladder 10 shown in FIG. 1, except that the vertical pole 2 of the stepladder 2, 2 is arranged in an eight-character shape of Chinese characters. 2 is connected to the horizontal step bars 3 and 3 in the same manner as the base 1 of the extension ladder.

  As shown in FIG. 2, the vertical rod 2 in the illustrated embodiment is an aluminum shape having a U-shaped cross section, for example. As shown in FIGS. 2 and 3, the step bar has a trapezoidal shape with a narrow cross section. The step bar 3 is fixed by, for example, fixing the rivet 4 so that both ends of 3 are inserted inside the U-shape of the vertical rod 2.

  As shown in FIGS. 1 and 3, the step bar 3 is fixed to the vertical rod 2 at a relative position in which the thin side faces the front side.

  On the other hand, as shown in FIGS. 1 and 4, at least one (two in FIG. 1) hooks 5 and 5 are integrally coupled to the lowermost step bar 3 of the base body.

  As shown in FIG. 5, the hooking body 5 has a front hanging portion 6 that is parallel to the base body protruding from the surface side, and is fixed to the step bar 3 by screws 7, for example.

  On the other hand, as shown in FIGS. 1 and 6, an engagement rod 8 is integrally attached to the uppermost portion of the base 1 at a position parallel to the step bar 3.

  As shown in FIG. 6, the engagement rod 8 has a V shape in which a projection shape with respect to a plane perpendicular to the vertical rod 1 of the base is opened on the back side (upward in FIG. 6).

  Therefore, when the V-shape of the engagement rod 8 is leaned against a utility pole or standing tree (see FIG. 10), the engagement rod 8 will hold the utility pole etc., so that the upper end of the extension ladder does not move and the ladder is stable. To do.

  For the reasons described above, it is desirable to rubberize the V-shaped rear surface (the upper surface in FIG. 6) of the engagement rod 8.

  Further, as shown in FIG. 1, above the hook body 5, there is fixedly attached to the ladder or stepladder so that the base body in which the hook body is engaged with an arbitrary step bar of the ladder or stepladder from the back side. A mechanism 9 is provided.

  As shown in FIGS. 7 to 9, the fixing mechanism 9 is provided in the vicinity of the vertical hook 2 (see FIG. 1) above the hook body 5 or in the horizontal direction of the vertical hook 2 above the hook body. The support shaft 11 (see FIG. 9) is provided.

  Here, the meaning of the vicinity of the vertical rod 2 in the horizontal direction means that the support shaft 11 does not penetrate the vertical rod 2.

  The support shaft 11 is not a tangible object but an abstract concept, and is a rotation center line of an operation lever described later.

  As shown in FIGS. 8 and 9, the support shaft 11 in the illustrated embodiment includes first and second metal fittings 13 and 14 that are bolted 12 to the vertical rod 2 of the extension ladder so that the vertical position can be adjusted. It is carried on the free end (left end in FIG. 9).

  The first and second metal fittings 13 and 14 in the illustrated embodiment are thick plate members whose cross sections are bent in a substantially L shape, and the vertical position is adjusted along a long hole 15 formed in the back surface of the vertical gutter 2 of the base body. It is installed as possible.

  That is, as shown in FIGS. 8 and 9, the male screw portion of the bolt 12 passes through a round hole (not shown) formed on the back surface (horizontal portion in FIG. 9) of the second metal fitting 14 and is a long hole of the vertical rod 2. 19 is inserted and screwed into a female screw hole formed on the back surface of the first metal fitting.

  Therefore, if the bolt 12 is loosened, the first and second metal fittings integrally connected through the bolt are moved up and down along the elongated hole 15, placed at an appropriate position, and the bolt 12 is tightened, the first and first The two metal fittings can be securely fixed to the vertical rod 2 of the base.

  In the illustrated embodiment, the side edge of the spine of the first metal fitting 13 is designed to be joined to the inner surface of the side plate of the vertical shaft 2, thereby preventing the rotation of the first metal fitting 13 around the bolt 12. Applied.

  Further, as shown in FIG. 9, the sleeves (the left part in FIG. 9) of the first and second metal fittings 13 and 14 are opened so as to have a relative angle of 90 degrees or more with respect to the back plate. As a result, the support shaft 11 is inclined upward in FIG.

  As described above, it is intentional that the support shaft is tilted. As will be described later, an operation lever provided so as to be able to turn around the support shaft can be swung with the step bar of the stepladder. The purpose is to strengthen the connection between the stepladder and the extension ladder.

  Returning to FIG. 8 and FIG. 9, a coaxial bolt hole (not shown) that is loosely fitted to the support bolt 16 is formed in the sleeve portions of the first and second fittings 13, 14, and the support bolt with the spring washer 17 is attached. The male screw part was opened in the bolt hole opened in the second metal fitting 14, the support shaft hole (not shown) opened in the base part of the operation lever 18 (see FIG. 7), the cylindrical spacer 19 and the sleeve part of the first metal fitting 13. After inserting the bolt hole, the nut is screwed onto the spindle bolt protruding inside the vertical rod 2.

  Then, the elasticity of the spring washer 17 is adjusted by adjusting the tightening amount of the nut, and the friction torque of the operation lever 18 is set to an appropriate value.

  In the embodiment shown in FIG. 9, if the torque of the operation lever 18 sandwiched between the sleeve of the second metal fitting 14 and the spacer 19 is increased, the movement of the operation lever becomes heavier. This is based on the idea that, when rotated so as to cross the step bar, the angular position is kept stable and the reliability is increased.

  However, as in the second aspect of the invention, if the operation lever 18 and the step bar of the stepladder are finally firmly coupled by using the turning, the rotation of the operating lever 18 before the turning is turned. The idea that can be smooth is also valid.

  In FIG. 9, the angle between the spine of the metal fitting and the sleeve is exaggerated so as to be much larger than 90 degrees. Therefore, the gap between the sleeve and the side plate of the vertical frame 2 is also larger than the actual.

  Actually, these two sleeve plates, the side plate of the vertical collar 2 and the like seem to overlap without any gap. In this case, if there is no spacer 19, the gap between the operation lever 18 and the sleeve of the first metal fitting 13 will be explained. The side plate of the vertical hook 2 sandwiched between the vertical hooks may be deformed because the vertical hook is made of a soft material such as aluminum.

  However, since the deformation is so small that it is not usually concerned, the spacer 19 can be omitted in this case.

  As shown in FIG. 8, when the first and second metal fittings 13 and 14 can be adjusted in the vertical direction, interference between the spacer 19 and the vertical shaft or the spindle bolt and the vertical plate is caused. The opening to avoid must still be vertically long.

  On the other hand, as shown in FIG. 7, the operation lever 18 is a lever having a slender shape projected onto the extension ladder. For example, as shown in FIG. 8, the operation lever 18 is slightly above the base perpendicular to the support shaft 11 (see FIG. 9). Is obliquely bent on the surface side of the extension ladder to form the first slope portion 19.

  Further, the upper end of the first inclined surface portion 19 is extended upward in parallel with the base portion to form an engaging surface 21, and the upper end of the engaging surface 21 is inclined obliquely like the first inclined surface portion 19. The free end (upper end) of the operation lever 18 is bent away from the extension ladder (or stepladder) so that the operation lever 18 can be easily operated.

  On the other hand, as shown in FIGS. 7 and 8, a fixed piece 22 made of hard rubber or synthetic resin housed in an unnumbered holder having a U-shaped cross section is screwed to the upper surface of the first inclined surface portion 19. ing. For example, a bicycle brake can be used as the fixed piece 22 as it is.

  The mounting position of the fixed piece 22 on the first inclined surface portion 19 is when the operating lever 18 is converted to the clock face when viewed from the front of the extension ladder and is at the 12 o'clock position (hereinafter referred to as top dead center). As shown in FIG. 5, the lower surface of the step bar 3 of the stepladder is set so that it slightly pushes up and comes into contact.

  Further, as shown in FIG. 8, a protrusion 23 is formed on the back surface side of the engaging surface 21 that faces the surface of the step bar 3 of the stepladder when the operation lever 18 is at the top dead center.

  In order to form the projection 23, for example, when the material of the operation lever 18 is a soft material such as aluminum, the surface portion corresponding to the projection 23 of the operation lever 18 is stamped toward the press or punch to form the depression 24. If formed, the protrusion 23 can be formed.

  Note that the protrusion amount of the protrusion 23 from the back surface of the operation lever may be as small as 1 mm or less, for example.

  Further, the protrusion 23 does not necessarily have to be integrated with the operation lever 18, and may be, for example, a screw head (not shown) screwed into the back surface side (right side in FIG. 8) of the engagement surface 21.

  Furthermore, the bent portion 26 between the engaging surface 21 and the inclined surface portion in FIG. 8 may be lowered to the position of the step bar 3 of the stepladder (not shown).

  The extension ladder according to one embodiment of the present invention configured as described above is an arbitrary step bar of a stepladder that is unfolded to form a ladder as shown in FIGS. 1 and 10 (the second step from the top in FIG. 1). The two hooking bodies 5 at the lowest stage of the extension ladder are hooked on the step bar) 3 from the back side of the stepladder (see FIGS. 1 and 5).

  Next, after the base body engaged with the back surface side of the stepladder is brought into contact with the back surface of the stepladder through the hook, the free ends of the operation levers 18 and 18 face each other, that is, FIG. In FIG. 1, the operating levers 18 and 18 that have penetrated to the surface side of the stepladder in a state where the right operating lever 18 is rotated approximately 180 degrees counterclockwise and the left operating lever is rotated approximately 90 degrees clockwise, as shown in FIG. Each is turned upward.

  Then, when the operating lever 18 is at a top dead center position orthogonal to the step bar 3 of the stepladder, the fixing piece 22 pushes up the lower side of the step bar 3 of the stepladder, and the protrusion 23 comes into pressure contact with the surface of the step bar.

  As described above, the support shaft 11 of the operation lever 18 is inclined upward in FIG. 9 and actually in the horizontal direction.

  That is, FIG. 9 shows a horizontal section of the support shaft portion of the extension ladder, and the U-shaped concave portion of the vertical shaft 2 faces downward, so when applied to FIG. The state is seen with the washer 17 facing down.

  FIG. 9 shows the left support shaft 11 and the operation lever in FIG. 1, and the support shaft 11 of the left operation lever 18 is inclined slightly outward, that is, to the left in a plane including the support shaft and perpendicular to the base. On the contrary, the support shaft 11 of the right operating lever 18 is inclined to the right.

  Therefore, when the left and right operation levers 18 and 18 are turned counterclockwise and clockwise, respectively, the free end portion of the operation lever 18 comes close to the step bar 3 of the stepladder, and the projection 23 on the back side thereof (see FIG. 8). Is rubbed against the surface of the step bar 3, so that the engagement between the step bar and the operation lever 18 becomes stronger, and the extension ladder and the stepladder are securely coupled.

  As shown in FIG. 1, the operation lever 18 actually rotates the left operation lever 18 a little counterclockwise (the right one is clockwise).

  The reason is that when the operation lever 18 is rotated counterclockwise in FIG. 7, it is blocked by a stopper 25 which is a bent portion of the second metal fitting 14, and when it is rotated counterclockwise, the fixed piece 22 is Further, since the step bar of the stepladder has to be pushed up, the operation lever 18 is stable when it is slightly lowered from the top dead center position.

  When the stepladder and the extension ladder are stored or transported in a warehouse or the like, the extension ladder may be combined between the leg portions of the stepladder as shown in FIG.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Vertical rod 3 Step bar 4 Rivet 5 Hook 6 Front drooping portion 7 Screw 8 Engagement rod 9 Fixing mechanism 10 Stepladder 11 Support shaft 12 Bolt 13 First metal fitting 14 Second metal fitting 15 Elongated hole 16 Support shaft bolt 17 Spring Washer 18 Operation lever 19 First slope portion 21 Engagement surface 22 Fixed piece 23 Projection 24 Depression 25 Stopper 26 Bending portion

Claims (2)

  A ladder-shaped base body in which a pair of vertical rods are connected by a plurality of horizontal step bars, and an L-shaped member integrally joined to the lowermost step bar of the base body. At least one hook projecting to the side, and a V-shaped projection mounted on the top surface of the base at a position parallel to the step bar and projected onto the plane perpendicular to the vertical plane of the base. An engagement rod, and a fixing mechanism that removably couples the base body, which is hooked to an arbitrary step bar of the stepladder from the back side, to the stepladder, and the fixing mechanism includes a base body above the hook body. A vertical shaft or a pair of left and right support shafts that are substantially perpendicular to a base that is rotatably supported in the vicinity of the vertical shaft, and a base end that is pivotally supported by each of the support shafts and is parallel to the base. And a fixed piece and protrusion on the back side A pair of left and right operating levers, and a base engaged with the back side of the stepladder via the hooking body is brought into contact with the back side of the stepladder, and then the free ends face each other. The operation levers that have penetrated the surface of the stepladder are each turned upward, and at the top dead center position perpendicular to the step bar of the stepladder, the fixed piece pushes up the lower side of the step bar of the stepladder, and the protrusion is the surface of the step bar Further, the extension ladder for stepladder is characterized in that each operation lever is fixed by a stopper at an angular position slightly rotated outward from the top dead center position.   2. The extension ladder for stepladder according to claim 1, wherein the support shaft of the operation lever is inclined slightly outward in a plane including the support shaft and perpendicular to the base body.

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