JP6200694B2 - Auxiliary ladder for manhole - Google Patents

Description

  The present invention relates to an auxiliary ladder for manholes that can be safely transferred from the ground to a step for a footrest provided in the manhole.

  A step for stepping is provided on the side wall in the manhole. An operator can use this step to descend into the manhole. Generally, a manhole is provided with a minimum space enough for one worker to pass. In most cases, no handrail is provided. For this reason, there is a risk of falling if the step is removed. When such a step is provided in the manhole, it is most dangerous that the upper body is on the ground and the step cannot be grasped by hand.

  On the other hand, the fixture which attaches an auxiliary ladder to the opening of a manhole is considered conventionally so that it can move to the manhole safely from the ground (for example, refer patent document 1). An example of such a configuration is shown in FIG.

  The manhole ladder mounting tool 100 of FIG. 9 includes a support base 101 on which a handrail frame 105 and a ladder can be attached to a part of an opening edge 120 of the manhole. The ladder fixture 100 includes a support base 101, a handrail frame 105 connected to the upper side of the support base 101, and a ladder support unit 106 connected to the lower side of the support base 101. Although not shown, the ladder support portion 106 can be hooked on the support bar 106a at the upper end of the ladder extending into the manhole.

  The support base 101 includes an upper strip plate 102 that contacts the upper surface of the opening edge 120, a contact plate 103 that contacts the inner wall, and a lower strip plate 104 that contacts the lower surface. The upper band plate 102 is fastened and fixed to the upper surface of the opening edge 120 via a fastening hole 102a by a bolt or the like, and the lower band plate 104 is fixed to the lower surface of the opening edge 120 via a bolt hole 104a. .

  When such a manhole ladder attachment 100 is used, it is possible to safely go to a step in the manhole while placing a hand on the handrail frame 105 extending to the ground.

JP 2005-2696 A

  However, the manhole ladder mounting tool 100 in FIG. 9 is such that the support base 101 is fixed to only a part of the opening edge 120 of the manhole. For this reason, when a large force is applied to the direction in which the handrail frame 105 is inclined (the center direction of the manhole, etc.), the support base 101 may be detached from the opening edge 120. In the unlikely event that the support base 101 is detached, there is a risk of falling into the manhole, which is dangerous.

  In addition, in order to prevent the support base 101 from being detached from the opening edge 120 and to strengthen the members and the clamping force so as not to cause deformation, each member is designed to be thick and the whole becomes large and the weight increases. Resulting in. If it becomes so, conveyance and installation will become difficult and work efficiency will fall remarkably.

  Accordingly, in order to solve the above-described problems, an object of the present invention is to provide an auxiliary ladder for manhole that can obtain a sufficient supporting force according to a load during use with a simple and lightweight configuration.

To achieve the above object, the auxiliary ladder for manholes of the present invention has a flange portion that can be placed on the opening edge of the manhole, and can be connected to a ring-shaped ladder mounting tool having a connecting portion, and to the connecting portion. A connecting portion having a connecting arm extending substantially perpendicular to the longitudinal direction and having an abutment arm substantially parallel to the connecting arm and capable of contacting the inner wall of the manhole at a lower position ; A bolt part that is erected substantially at right angles from the upper surface of the part, and is formed with a screw groove only on both ends, and a nut part that can be screwed into the screw groove on both ends. A notch having a width in which the bolt portion can be fitted is formed in the orthogonal direction, and a nut receiving recess in which a part of the nut portion can be fitted is formed in the extending direction of the bolt portion .

  In addition to the above-described structure, the auxiliary ladder for manholes of the present invention has a mounting pin projecting downward in parallel with the longitudinal direction of the auxiliary ladder in the connecting arm, A mounting hole is formed at a position where the mounting pin with the bolt portion fitted in the notch can be inserted.

  As described above, according to the present invention, when the worker uses the auxiliary ladder, the center of gravity of the auxiliary ladder on which the worker rides is biased toward the center of the manhole. As a result, with the connecting arm connected to the connecting portion of the ladder fixture as a fulcrum, a force toward the center side of the manhole acts on the upper end side of the auxiliary ladder, and a force toward the outer diameter side of the manhole appears on the lower end side. The force by which the abutting arm pushes the inner wall of the manhole increases. Since the abutting arm is arranged substantially parallel to the connecting arm, the reaction force of the force by which the abutting arm pushes the inner wall of the manhole acts as a pushing force to the opposing inner wall via the ring-shaped ladder attachment. .

  Thus, when the worker uses the auxiliary ladder, the weight of the worker is distributed to the force that presses the inner wall of the opposing manhole by the contact arm and the ladder mounting tool, so the manhole auxiliary ladder is changed to the manhole. The fixing force increases and the stability of the work improves. Moreover, since sufficient fixing force with respect to the manhole is generated as necessary, the member can be reduced in size and weight, and work efficiency can be improved.

  Further, according to the present invention, when the bolt portion is inserted into the notch and fastened so as to sandwich the connecting arm between the upper surface of the flange portion and the lower portion of the nut portion, a part of the nut portion is a nut receiving recess. It becomes possible to effectively restrict the movement of the connecting arm in the extending direction. Further, when the bolt portion is inserted into the notch, if the positioning is performed in the central region where the screw groove is not formed, the screw groove and the notch do not interfere with each other, and the screw groove can be prevented from being crushed. The durability can be improved.

  Further, according to the present invention, when the bolt part is inserted into the notch, the mounting pin can be inserted into the mounting hole. When the mounting pin is inserted into the mounting hole (when the center of the mounting hole and the shaft of the mounting pin coincide), the position of the bolt part with respect to the notch is fixed, so when inserting the mounting pin along the mounting hole Thus, it is possible to prevent the screw groove formed below the bolt portion from interfering with the notch.

It is a whole perspective view of the auxiliary ladder for manholes concerning an embodiment of the invention. It is a three-dimensional exploded view of the auxiliary ladder for manholes of FIG. It is the end elevation which showed the structure of the connection part and connection arm of the auxiliary ladder for manholes of FIG. It is an enlarged view of the locking mechanism of the auxiliary ladder for manholes of FIG. It is sectional drawing explaining the angle adjustment function of a locking mechanism. It is the end elevation which showed the relationship of the external force which acts on the auxiliary ladder for manholes of FIG. It is the perspective view which showed another use condition of the auxiliary ladder for manholes. It is the perspective view which showed another use condition of the auxiliary ladder for manholes. It is the figure which showed the conventional ladder attachment tool for manholes.

  Hereinafter, an auxiliary ladder for manholes according to an embodiment of the present invention will be described with reference to the drawings.

  First, the overall configuration will be described with reference to FIGS. 1 and 2. FIG. 1 is an overall perspective view of a manhole auxiliary ladder 1 according to the present embodiment. FIG. 2 is a three-dimensional exploded view of the manhole auxiliary ladder 1 shown in FIG.

  Referring to FIG. 1, a manhole auxiliary ladder 1 includes a ring-shaped ladder attachment 2 having a flange portion 2a that can be placed along an opening edge of a manhole, and two auxiliary ladders 6 attached thereto. It has. As shown in FIG. 2, the ring-shaped ladder attachment 2 is detachably attached to the ladder attachment 2.

  These auxiliary ladders 6 are connected to the connecting portion 3 of the ladder fixture 2 by connecting arms 8 extending in a direction perpendicular to the longitudinal direction. The connecting portion 3 and the connecting arm 8 will be described in detail later with reference to FIG.

  Further, two lock portions 12 are provided on the inner side of the ladder fixture 2 for fixing to the opening edge of the manhole. The lock unit 12 will be described in detail later with reference to FIGS. 4 and 5.

  In the configuration shown in FIG. 1, two auxiliary ladders 6 having the same shape are arranged upside down and connected to the ladder fixture 2. As described above, the auxiliary ladder 6 according to the present embodiment can be attached in any direction up and down (see also FIG. 2). For example, it is convenient to arrange the auxiliary ladder 6 on the side connected to the step for stepping in the manhole so as to largely protrude on the ground, and arrange the auxiliary ladder 6 on the opposite side so as to extend largely into the manhole. In other words, if you put your hand on the upper end of the auxiliary ladder 6 that protrudes greatly on the ground and put your foot on the lower end side, you can smoothly put your foot on the steps in the manhole just by getting down. In addition, since it is possible to sit on the auxiliary ladder 6 on the side where the upper end protrudes short on the ground side, it is convenient for operations such as lowering tools in the manhole.

  Next, a connection configuration between the connection arm 8 of the auxiliary ladder 6 and the connection portion 3 of the ladder attachment 2 will be described with reference to FIG. FIG. 3 shows an end view cut at the center of the connecting portion 3 and the connecting arm 8. 3A shows a state before the attachment pin 8c of the auxiliary ladder 6 is inserted into the attachment hole 4 of the ladder attachment 2, and FIG. 3B shows the auxiliary ladder 6 as the ladder attachment 2. On the other hand, the state where the connection is completed is shown.

  As can be seen from FIG. 3 (a), the connecting part 3 on the ladder mounting tool 2 side is composed of a bolt part 3a erected on the flange part 2a and a nut part 3b screwed into the bolt part 3a. ing. In the bolt part 3a, screw grooves 3c are formed on the upper end side and the lower end side (flange part 2a side), but are not formed around the center. Since the state shown in FIG. 3A is a state before connection, the nut portion 3b is screwed into the screw groove 3c on the upper end side of the bolt portion 3a and is in a retracted state. In this state, the connecting arm 8 of the auxiliary ladder 6 approaches the bolt portion 3a.

  A notch 8a is formed at the tip of the connecting arm 8 in a width that allows the bolt portion 3a to be fitted therein. Here, referring once to FIG. 2, a nut receiving recess 8b having a size capable of fitting the lower end side of the nut portion 3b is formed around the notch 8a in the extending direction of the bolt portion 3a. . Returning to FIG. 3 (a), when the cross section of the connecting arm 8 is seen, the nut receiving recess 8b is formed on both upper and lower surfaces, so that even if the auxiliary ladder 6 is disposed upside down, the nut portion The lower end of 3b can be fitted into the nut receiving recess 8b.

  In the present embodiment, the axial center of the mounting pin 8 c is configured to coincide with the center of the mounting hole 4 when the bolt portion 3 a is accommodated in the notch 8 a of the connecting arm 8. Therefore, the mounting pin 8c can be aligned with the mounting hole 4 simply by fitting the vicinity of the center where the screw groove 3c of the bolt portion 3a is not formed in the notch 8a of the connecting arm 8 and performing alignment. . Then, the auxiliary ladder 6 can be easily assembled to the ladder attachment 2 by moving downward as it is and inserting the attachment pins 8 c into the attachment holes 4. Since the positioning can be easily performed in this way, work efficiency is not lowered even during night work.

  As can be seen from FIG. 3A, the mounting pin 8c is formed sufficiently longer than the length in which the screw groove 3c on the flange portion 2a side is formed. The attachment pin 8c is inserted into the attachment hole 4 before reaching the groove 3c. That is, the notch 8a does not interfere with the screw groove 3c, and the mounting pin 8c is guided by the mounting hole 4 so that the auxiliary ladder 6 can be accurately connected. Therefore, unnecessary wear of the screw groove 3c can be prevented, and durability can be improved.

  In FIG. 3B, the nut portion 3 b is tightened from above the connecting arm 8 of the assembled auxiliary ladder 6. As described above, since the nut receiving recess 8b into which the lower end side of the nut portion 3b can be fitted is formed in the connecting arm 8, when the fastening is completed, in addition to the engagement between the mounting pin 8c and the mounting hole 4, Due to the engagement between the nut portion 3b and the nut receiving recess 8b, the auxiliary ladder 6 is restricted from moving horizontally in the double direction.

  Further, focusing on the work efficiency, since the screw groove 3c is not formed in the central region of the bolt portion 3a, an unnecessary rotation operation is performed when moving between the upper retracted position and the lower fastening position. There is no need to do this, and work efficiency is greatly improved.

  Next, the configuration and function of the lock unit 12 will be described with reference to FIGS. 4 and 5. FIG. 4A shows a locked state with respect to the opening edge of the manhole, and FIG. 4B shows a unlocked state. Here, for convenience of explanation, illustration of the configuration on the opening edge side of the manhole is omitted.

The lock portion 12 according to the present embodiment includes an upper plate 12d and a lower plate 12e that are arranged in parallel to the inner wall side of the ladder attachment 2. And the rotating shaft 12b is penetratingly arranged with respect to these upper board 12d and the lower board 12e. An operating lever 12a is connected at a right angle above the upper plate 12d in the rotating shaft 12b. An engaging claw 12f that engages with the inner wall of the manhole is connected to the lower side of the lower plate 12e. With such a configuration, it is possible to easily engage and lock the engaging claw 12f with the concave portion or the like of the opening edge of the manhole only by rotating the lever 12a.

  In the present embodiment, since the lower plate 12e is formed in a substantially L-shaped cross section, the engaging claws 12f are protected without coming into direct contact with the floor even when placed on the floor.

  Further, a spring 12g is externally fitted between the upper plate 12d and the lower plate 12e in the rotating shaft 12b. The adjustment nut 12c is screwed to the upper end side of the spring 12g, and the adjustment nut 12c is lifted by the spring 12g.

  With such a configuration, it is possible to lift the rotating shaft 12b against the bias of the spring 12g. When the adjustment nut 12c is turned and moved downward, the position of the adjustment nut 12c is always in contact with the lower surface of the upper plate 12d by the spring 12g, so that the rotary shaft 12b is relatively lifted. Conversely, when the adjustment nut 12c is turned and moved upward, the rotary shaft 12b is relatively lowered.

  In this manner, the height of the engaging claw 12f of the lock portion 12 can be adjusted in accordance with the shape of the opening edge of the manhole where the ladder fixture 2 is installed.

  Here, the structure of the opening edge on the manhole side is not described in detail. For example, this embodiment is applied to a pressure-release type manhole having a recess formed at a predetermined depth from the opening side. Such a ladder fixture 2 is suitable. In addition to the pressure release type, if a recess is formed on the opening side, the manhole auxiliary ladder 1 can be fixed by engaging the engaging claw 12f with the recess.

  Next, the angle adjustment function of the lock unit 12 will be described with reference to FIG. FIG. 5 schematically shows a cross section of the manhole provided on the slope. For convenience of explanation, one side of the opening edge 50 of the manhole is enlarged, and only the lock part 12 on one side is shown.

  In general, manholes in the ground are arranged vertically even on slopes. For this reason, the extending direction of the manhole and the inclination direction of the ground 53 may not be orthogonal to each other. However, if the auxiliary ladder 6 is installed in accordance with the inclined opening edge 50, the step for stepping in the manhole and the auxiliary ladder 6 are not smoothly continuous, and the possibility that the operator steps off the foot increases.

  Considering this point, the manhole auxiliary ladder 1 according to the present embodiment is provided with an angle adjusting function in the lock portion 12. As already described with reference to FIG. 4, the height position of the rotary shaft 12b can be adjusted by adjusting the adjustment nut 12c. In FIG. 5, a plate-like member is placed on the lower side of the flange portion 2a on the lower inclined side (right side in FIG. 5) so that the ladder fixture 2 is arranged in a direction orthogonal to the direction in which the manhole extends. 14 is interposed. Then, as described with reference to FIG. 4, the engaging claw 12f (shown by a solid line in the figure) lifted by the thickness of the spacer 14 is lowered by the adjusting nut 12c to be recessed in the inner wall 50a of the manhole. It is possible to adjust so that it can be engaged (a state indicated by a broken line in the drawing).

  Next, the action of an external force when using the manhole auxiliary ladder 1 configured as described above will be described with reference to FIG.

  FIG. 6: has shown the end elevation cut | disconnected by the surface which passes along the connection part 3 about the state installed in the manhole. In addition, illustration is abbreviate | omitted about the fine shape around the opening of a manhole, and the fine structure on the flange part 2a unnecessary for description.

  Referring to FIG. 6, auxiliary ladder 6 disposed on the side of manhole where step 52 for stepping is provided is assembled to ladder attachment 2 so as to extend greatly on the ground side. Here, the side arranged so as to extend greatly on the ground is called an auxiliary ladder 6A, and the side arranged so as to extend greatly to the inside of the manhole is distinguished as an auxiliary ladder 6B.

  Thus, when entering the manhole, the worker puts his hand on the upper end 6a on the auxiliary ladder 6A side, puts his foot on the lower end 6b, and approaches the step 52. At this time, since the center of gravity of the operator is on the center side of the manhole, the upper end 6a side of the auxiliary ladder 6A receives a force for rotating the connecting arm 8 around the center of the manhole.

  On the other hand, paying attention to the lower end 6b side on which the foot is placed, similarly, since the center of gravity of the operator is on the center side of the manhole, the force to rotate toward the outer diameter side of the manhole around the connecting arm 8 is a fulcrum. Work.

  That is, the contact arm 10 disposed below the connecting arm 8 is strongly pressed against the inner wall 50a of the manhole (in the direction of the arrow 31), and the peripheral portion of the connecting arm 8 (ladder attachment 2) is the center of the manhole. A force toward the side (direction of arrow 32) is received. In other words, the ladder fixture 2 is strongly pressed by receiving a reaction force on the opposite side of the manhole on the side where the contact arm 10 is in contact with the inner wall 50a.

  Therefore, just by the operator getting on the auxiliary ladder 6A, the auxiliary ladder 6A and the ladder fixture 2 are stretched toward the opposite sides in the horizontal direction and are firmly fixed to the opening edge 50 of the manhole.

  Next, when looking at the auxiliary ladder 6B, as described above, the operator can sit on the upper end 6c. At this time, since the operator's weight is added to the center side of the manhole from the connecting arm 8, the abutting arm 10 provided below the connecting arm 8 is pressed to the inner wall 50a side of the manhole (direction of arrow 33). . Further, when the operator goes deeply into the manhole, if the foot is placed on the lower end side 6d, the lower abutting arm 10 is placed on the inner wall 50a of the manhole (in the direction of the arrow 33), as described above. Pressed. And as this reaction force, the peripheral part (ladder attachment 2) of the connection arm 8 receives the force which goes to the center side (direction of arrow 34) of a manhole.

  As described above, a sufficient supporting force is generated according to the weight of the operator during use, while being easily fixed by the two lock portions 12, so that safety during work is ensured. Therefore, it is possible to realize cost reduction and weight reduction, and the work efficiency is significantly improved.

  In addition, not only when the operator puts his / her feet on the auxiliary ladder 6, but also when the pulley for hanging a load is attached to the auxiliary ladder 6, the contact arm 10 of the auxiliary ladder 6 is similarly Since the inner wall 50a is pressed, it is possible to safely carry heavy objects.

Next, another use state of the auxiliary manhole ladder according to the present embodiment will be described with reference to FIG. As shown in FIG. 7, a hatch-type safety lid 16 can be attached on the flange portion 2 a of the ladder attachment 2. Thereby, except when the operator passes through the opening, as shown in FIG. 7B, the safety lid 16 can be closed to prevent the operator and tools from falling. The safety lid 16 shown in FIG. 7 is shown as an example of a configuration in which five horizontal bones are combined in a direction orthogonal to two parallel longitudinal bones, but the safety lid 16 is covered. If the net-like member is further combined, it is possible to effectively prevent a small component from dropping, so that safety is further improved. In addition, since the safety lid 16 is connected to the ladder fixture 2 through the hinge portion 16a, an operator entering the manhole can easily perform the opening / closing operation by himself / herself.

  Furthermore, as shown in FIG. 8, it is also possible to combine the guard fence 18. Here, the structure which can cover the whole perimeter area of the ladder attachment 2 by combining four curved guard fences 18 is shown. Further, if one of the four protective fences 18 is provided so as to be opened and closed by a hinge (not shown), the operability is improved.

  In the above-described embodiment, the configuration in which two auxiliary ladders 6 are installed with respect to the ladder mounting tool 2 is shown as an example. However, even if only one is provided, the manhole auxiliary ladder is stabilized at the opening of the manhole. It is possible to sufficiently obtain the effect that it can be fixed.

  Further, in the above embodiment, in the connecting arm 8 of the auxiliary ladder 6, the mounting pin 8 c and the nut receiving recess 8 b are provided on both the upper and lower sides, and the abutting arm 10 is also provided symmetrically with respect to the connecting arm 8. The configuration is shown as an example. However, the same effect can be obtained even if it is provided only on one side.

  Further, in the above-described embodiment, the contact arm 10 has been illustrated as an example of a configuration in which the contact arm 10 is provided at approximately equal intervals in the vertical direction with the connection arm 8 as the center, but may not be equally spaced.

  In the above-described embodiment, as an example of the connecting portion 3, a configuration including the bolt portion 3 a and the nut portion 3 b in which the screw groove 3 c is formed only on both ends is shown as an example. Any locking means may be used.

  In the above embodiment, the configuration in which the mounting pin 8c and the mounting hole 4 are provided to connect the connecting arm 8 and the ladder mounting tool 2 is shown as an example. However, the mounting pin 8c and the mounting hole 4 are illustrated. The auxiliary ladder 6 may be connected only by the connecting portion 3 without using the above.

  Since the auxiliary ladder 1 for manholes of the present invention can stably fix the ladder to the opening edge 50 and can move smoothly to the steps inside, it can be used in addition to electric facilities and manholes in water and sewage facilities. Is also useful as an auxiliary ladder attached to an opening of a water storage tank or the like.

DESCRIPTION OF SYMBOLS 1 Manhole auxiliary ladder 2 Ladder fixture 2a Flange part 3 Connection part 3a Bolt part 3b Nut part 3c Screw groove 4 Mounting hole 6, 6A, 6B Auxiliary ladder 6a, 6c Upper end 6b, 6d Lower end 8 Connection arm 8a Notch 8b Nut Receiving recess 8c Mounting pin 10 Contact arm 12 Locking portion 12a Lever 12b Rotating shaft 12c Adjusting nut 12d Upper plate 12e Lower plate 12f Engaging claw 12g Spring 14 Spacer 16 Safety lid 16a Hinge portion 18, 18a Guard fence 50 Open edge 50a Inner wall 52 Step 53 Ground

Claims (2)

A ring-shaped ladder mounting tool having a flange portion that can be placed on the opening edge of the manhole, and a connecting portion;
An auxiliary ladder having a connecting arm connectable to the connecting portion and extending substantially perpendicular to the longitudinal direction and having an abutting arm capable of contacting the inner wall of the manhole at a lower position substantially parallel to the connecting arm; equipped with a,
The connecting portion is configured by a bolt portion that is erected substantially at a right angle from the upper surface of the flange portion, and has a screw groove formed on only both end sides, and a nut portion that can be screwed into the screw groove on both end sides. ,
The connecting arm has a notch having a width that allows the bolt portion to be inserted in a direction orthogonal to the bolt portion, and a nut receiver in which a part of the nut portion can be inserted in the extending direction of the bolt portion. An auxiliary ladder for manholes, characterized in that a recess is formed . The connection arm has a mounting pin that protrudes downward in parallel with the longitudinal direction of the auxiliary ladder,
2. The manhole support according to claim 1 , wherein a mounting hole is formed in the ladder mounting tool at a position where the mounting pin in which the bolt portion is fitted can be inserted into the notch. ladder.