JP4563091B2 - Manhole iron lid bite release device - Google Patents

Description

  The present invention relates to an apparatus for releasing the biting of an iron lid with respect to a receiving frame of a manhole when opening the iron lid of a manhole.

  The manhole's iron cover is repeatedly subjected to loads due to vehicle traffic, etc., and dust and other foreign objects have entered the slight gap between the iron cover and the receiving frame. The iron lid bites into the receiving frame strongly. Therefore, when the iron lid is opened in order to perform communication work or the like in the manhole, it is necessary to first release the iron lid from biting into the receiving frame.

  Conventionally, there is a technique disclosed in Patent Document 1, for example, as means for releasing the iron cover from biting into the manhole receiving frame. In this technique, the bottom end of the lever is connected near one end of the support shaft that is longer than the diameter of the manhole. And the large diameter wheel is provided in the both ends of the support shaft, and the small diameter wheel is provided in the lower end part of the lever. Further, the support shaft is provided with a hook that can be engaged with the hole of the iron lid. By engaging the hook with the hole of the iron lid and tilting the lever, the lever lifts the iron lid while changing the fulcrum of the small-diameter wheel and the large-diameter wheel in order.

However, in order to release the iron cover from biting into the manhole receiving frame, a very large force (about 1 × 10 ⁴ N) is required. Therefore, it is conceivable to use a hydraulic cylinder or a jack as a means for obtaining a sufficient force for releasing the iron lid.

For example, Patent Document 2 discloses an apparatus using a hydraulic cylinder for removing a manhole receiving frame. In this technique, a hydraulic cylinder is arranged upward in the center of a support frame supported by three legs. A rod member that extends downward through the support frame is provided on the movable frame that moves up and down by the operation of the hydraulic cylinder, and a hook is provided at the lower end of the rod member. And in order to remove the receiving frame of a manhole, an apparatus is installed in the appearance which straddled the manhole with each leg, and a hook is engaged with a receiving frame. In this state, by operating the hydraulic cylinder to raise the movable frame, the receiving frame is pulled out from the ground and removed.
Japanese Utility Model Publication No. 61-146546 JP 2001-40686 A

  The apparatus disclosed in Patent Document 2 has a large and complex structure, and it is difficult to secure an installation space depending on the location of the manhole. In addition, since an expensive hydraulic cylinder is used, even if this device is used as a device for releasing the iron cover from biting into the manhole receiving frame, the cost does not match.

  Therefore, in order to simplify the structure and reduce the installation space, it is possible to improve the above-described apparatus to be arranged on one side of the manhole. However, in that case, the hook engaged with the hole of the iron lid and the axis of the hydraulic cylinder that pulls up the hook are biased from each other. As a result, the apparatus may fall over due to the deviation of the center of gravity during the work.

The present invention is intended to solve such a problem, and one of its purposes is to prevent a fall due to a shift in the center of gravity during the operation even though the structure is simple and does not take up installation space. In addition, it is possible to use a general low-cost single-acting jack.
Another object of the present invention is to prevent the road surface around the manhole from being damaged, and to simplify the installation and removal at the work site.

The present invention is for achieving the above object, and is configured as follows.
The invention according to claim 1 is a release device used to release the iron cover from biting into the manhole receiving frame, the jack capable of raising the lifting head by raising the lift, and one side of the manhole. A jack stand that can be installed and on which a jack can be placed so that the lifting head is positioned directly above the opening hole provided in the iron lid, and upper and lower beams on both upper and lower sides of this jack stand. Each of the frame-shaped hook frames, and a hook provided on the lower beam of the hook frame and engageable with the opening hole of the iron lid from directly above.
Each of these jacks, jack stands, and hook frames are separate parts. The jack stand is formed on a support leg that can be placed on a receiving frame of a manhole, a jack mounting portion that is located above the support leg, and a lower part of the support leg, and the lower beam of the hook frame can be positioned on the jack stand. Possible opening part. The upper beam of the hook frame is set so as to be supported from below by the lifting head of the jack mounted on the jack mounting portion of the jack table.

According to this configuration, when the hook is engaged with the opening for opening the iron cover, and the lifting head of the jack is lifted to separate the manhole's iron cover from the receiving frame, the hook and the lifting head of the jack are on the same axis. Can be located. This makes it possible to prevent overturning due to a shift in the center of gravity during work, despite the fact that it is a simple structure that does not take up installation space, only on one side of the manhole. Stable work can be performed using a jack.
In addition, since the reaction force of the load when the iron cover of the manhole is pulled away from the frame is received by the manhole receiving frame through the support legs of the jack stand, it is possible to prevent the road surface around the manhole from being damaged. And since it is comprised with few parts, such as a jack, a jack stand, and a hook frame, installation and removal at a work site are easy.

The best mode for carrying out the present invention will be described below with reference to the drawings.
FIG. 1 is a plan view of a manhole closed with a lid, and FIG. 2 is a longitudinal sectional view of FIG. As is well known, a ring-shaped iron receiving frame 12 is fixed to the upper edge of the concrete wall constituting the manhole 10. The manhole 10 is closed by fitting an iron lid 14 inside the receiving frame 12. The inner peripheral surface of the receiving frame 12 and the outer peripheral surface of the iron lid 14 are tapered to each other in order to suppress rattling of the iron lid 14 in the radial direction (FIG. 2). As described above, dust or the like enters between the taper surfaces, causing the iron lid 14 to bite into the receiving frame 12 strongly. Note that the iron lid 14 is provided with opening holes 14a and 14b (commonly referred to as “cork holes”) at locations near the outer periphery that face each other at an interval of 180 °.

  FIG. 3 is an external perspective view showing the jack stand 20 constituting the bite release device for the iron lid 14. FIG. 4 is an external perspective view showing the hook frame 30 that also constitutes the bite release device for the iron lid 14. This release device is roughly composed of three members: a jack base 20, a hook frame 30, and a jack 40 (FIG. 6).

  As shown in FIG. 3, the jack stand 20 includes a support leg 22 formed by bending a metal plate into an arc shape, and a jack mounting portion 24 on which the jack 40 is placed. As shown by the phantom lines in FIG. 1, the support leg 22 is bent following the curvature of the receiving frame 12 so as to be placed on a part of the receiving frame 12. Further, the support leg 22 is formed with a suitable open portion 22a cut out in a rectangular shape from the lower side to the upper side. The jack mounting portion 24 is fixed to the upper portion of the support leg 22 and is positioned so as to cover the upper surface created by the arc shape of the support leg 22. Then, rising pieces 24 a and 24 b projecting upward are provided at both front and rear ends of the jack mounting portion 24. A jack 40 is placed between the rising pieces 24a and 24b.

  As shown in FIG. 4, the hook frame 30 has a rectangular frame shape in which both ends of the upper beam 32 and the lower beam 33 are coupled by the left and right connecting bars 34. A shaft 35 extending downward is provided at an intermediate portion of the lower beam 33, and a hook 36 is fixed to a lower end portion thereof. This 36 can be inserted into and engaged with the opening hole 14a in the iron cover 14 of the manhole 10. This is shown in FIGS. 5 (a) and 5 (b).

  5A is a perspective view of a state immediately before the hook 36 is inserted into the opening hole 14a, and FIG. 5B is a perspective view of a state in which the hook 36 is engaged with the opening hole 14a. As shown in these drawings, in order to engage the hook 36 with the opening hole 14a, first, the hook frame 30 is set to the orientation shown in FIG. 5A with respect to the iron lid 14, and the opening hole 14a. Hook 36 is positioned directly above In this state, after the hook frame 30 is lowered and the hook 36 is inserted into the opening hole 14a, the entire hook frame 30 is rotated approximately 90 ° around the axis of the shaft 35 as shown in FIG. As a result, the hook 36 is engaged with the opening hole 14a. When the hook 36 is engaged with the opening hole 14a in this way, the jack base 20 and the jack 40 are set. The release device that has completed these sets is shown in FIG.

  FIG. 6 is a partial cross-sectional view showing a state before the start of work of the release device installed at the site. FIG. 7 is a partial cross-sectional view showing the work completion state of the release device. As shown in these drawings, the jack stand 20 has a state in which the lower beam 33 of the hook frame 30 is positioned in the opening 22 a of the support leg 22 and the support leg 22 is placed on the receiving frame 12 of the manhole 10. Installed at. That is, the jack stand 20 is installed in a state where the support legs 22 straddle the lower beam 33 of the hook frame 30.

  The jack 40 is a general hydraulically operated and inexpensive single-acting type, and the rod 44 can be protruded from the cylinder 42 by oil pressure by manual operation. 46 can be raised. The jack 40 is placed on the jack mounting portion 24 of the jack stand 20, and the upper beam 32 of the hook frame 30 is supported from below by the lifting head 46. At this time, it is considered that the axis of the jack 40 is aligned with the intersection X of the two virtual lines L1 and L2 shown in FIG. 1, and that the axis of the jack 40 and the connecting rod 34 of the hook frame 30 are parallel. Thereby, the raising / lowering head 46 of the jack 40 is located just above the opening hole 14a in the iron lid 14.

  In the release device installed in this manner, the hook 36 of the hook frame 30 and the lifting head 46 of the cylinder 42 are located on substantially the same line. Therefore, by operating the jack 40 and raising the elevating head 46, the hook frame 30 is lifted straight with respect to the jack base 20, and the iron lid 14 is pulled away from the receiving frame 12 of the manhole 10 through the hook 36 (FIG. 7). That is, the iron lid 14 is released from biting into the receiving frame 12, and thereafter, the iron lid 14 is removed from the manhole 10 by using a general iron lid opening / closing tool (not shown).

  In the work to release the iron lid 14, the hook 36 and the elevating head 46 are located on substantially the same line, so that even if the road surface is inclined, the device may be overturned due to the deviation of the center of gravity during the work. Trouble is prevented. In addition, since the load applied to the jack table 20 during work is received by the receiving frame 12 of the manhole 10 through the support legs 22, problems such as the depression of the road surface around the manhole 10 are also eliminated. Moreover, since the bite release device of the present embodiment is arranged on one side of the manhole 10, the installation space is small, and it is possible to cope with a space-constrained site. Furthermore, since the jack base 20, the hook frame 30, and the jack 40 are small and configured with a small number of parts, they can be easily installed and removed at the work site.

Top view of a manhole closed with a lid 1 is a longitudinal sectional view of FIG. External perspective view of jack stand External perspective view showing the hook frame The perspective view showing the operation | work for engaging a hook with the opening hole of an iron cover Partial sectional view showing the state of the bite release device before starting work Partial cross-sectional view showing the work completion status of the bite release device

Explanation of symbols

10 Manhole 12 Receiving Frame 14 Iron Cover 14a Opening Hole 20 Jack Stand 30 Hook Frame 36 Hook 40 Jack

Claims (1)

A release device used to release the iron cover from biting into the manhole's receiving frame, which can be lifted and lifted by the lifting head, can be installed on one side of the manhole, and on the iron cover A jack stand on which a jack can be placed so that the elevating head is positioned directly above the opening hole provided, and a frame shape in which the upper and lower beams can be positioned on both the upper and lower sides of the jack stand. And a hook that is provided on the lower beam of the hook frame and that can be engaged with the opening hole of the iron lid from directly above. The jack, the jack stand, and the hook frame are individually provided. The jack stand includes a support leg that can be placed on a manhole receiving frame, a jack mounting portion located above the support leg, and a support leg. It is formed in part, and a opening which can be positioned the lower beam of the hook frame, beams on the hook frame is supported from below by a jack stand of the jack mounting jack lifting head placed on portion Manhole iron lid bite release device that is set to

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