EP1174581A1

EP1174581A1 - Foothold for a manhole or the like

Info

Publication number: EP1174581A1
Application number: EP01115937A
Authority: EP
Inventors: Eizo Takahashi
Original assignee: Miyama Kogyo Co Ltd
Current assignee: FBS Miyama Co Ltd
Priority date: 2000-07-21
Filing date: 2001-06-29
Publication date: 2002-01-23
Also published as: CZ300852B6; GB2365056B; CZ20012507A3; GB2365056A; GB0018046D0

Abstract

There is provided a foothold (1) for a manhole or the like having a tread (2) provided with reflectors (8) thereon without impairing an efficient slip-prevention function on the tread (2) so as to surely and easily secure legs (4) of the foothold (1) to holes provided on a concrete wall such as a manhole. Accordingly, the foothold (1) can be fixed to the wall of a manhole and so forth with safety and is endurable in use for a long period of time. The foothold (1) for a manhole or the like comprises the tread (2), side portions (3) positioned at both sides of the tread (2), the legs (4) connected to free ends of the side portions (3) for insertion into a concrete wall, said tread (2), side portions (3) and legs (4) being integrally formed of a core (5), and a synthetic resin (6) for covering the core (5), the upper surface of the tread (2) being varied to incline upward from the central portion toward the ends thereof at an angle of 1 to 5 degrees and said upper surface of the tread (2) having slip prevention patterns (7) at the entire surface thereof, the reflectors (8) provided on the tread (2) at portions adjacent both ends thereof, a wave-shaped grip portion 9 provided on the tread (2) at an inner side thereof in the axial direction and another wave-shaped grip portion (10) provided at a lower surface of the tread (2) in the axial direction, belt-shaped projections (11) formed on the side portions (3) in the axial direction, blow receiving portions 13 formed on the tread (2) at the front ends of the side portions (3) to assist in embedding the legs (4) in a concrete wall, characterized in further comprising contact support pieces (12) provided to protrude from boundary portions between the side portions (3) and the legs (4) capable of contacting the concrete wall.

Description

The present invention relates to a foothold for a manhole or the like comprising a tread, side portions positioned at both sides of the tread and legs to be inserted into a concrete wall.
The applicant has U.S. Patent No. 5, 967,256 which has been issued October resist 19, 1999 and now known as shown in Fig. 4 wherein a foothold 21 for a manhole or the like comprises a tread 22, side portions 23 positioned at both sides of the tread, legs 24, 24 connected to free ends of the side portions 23 for insertion into a concrete wall, said tread 22, side portions 23 and legs 24 being integrally formed of a core 25, a synthetic resin 26 for covering the core 25, the upper surface of the tread 22 being varied to be inclined upward from the central portion toward the ends thereof at an angle of 1 to 5 degrees and said upper surface of the tread 22 having slip prevention patterns 27, reflectors 28 provided on the cornered-portions between the tread 22 and the side portions 23, a wavegrip portion 29 formed on the tread 22 at the inner side of the tread 22 in the axial direction, another wave-griped portion provided on the lower surface of the tread in the axial direction, belt-shaped projections 31 formed on the side portions 23 along the outer end portions in the axial direction, and blow receiving portions 33 formed on the tread at the front end side of the tread 22 to assist in embedding the foothold 21 for a manhole or the like in a concrete wall.
However, in this foothold 21 for a manhole or the like, since the belt-shaped projection 31 are forced to be formed on the end portions of the side portions 23, it is not easily to integrally form the foothold by the synthetic resin 26, and the strength of fixation of the belt-shaped projections 31 relative to the side portions 23 becomes weak. Further, since the blow receiving portions 33 are disposed at the front surface of the middle portion of the tread 22, a striking or blowing force works as a bending moment, thereby arising a problem that the foothold 21 is not efficiently struck to be embedded in the concrete wall.
The invention has been developed in view of the forgoing problems of the prior art, and the object of the invention is to provide a foothold for a manhole or the like having a tread provided with reflectors thereon without impairing an efficient slip-prevention function on the tread so as to surely and easily secure the legs of the foothold to holes provided on a concrete wall such as a manhole. As a result, the foothold can be fixed to the wall of a manhole with safety and so forth and is endurable in use for a long period of time.
To achieve the above object, the foothold of the invention comprises a tread, side portions positioned at both sides of the tread, legs connected to free ends of the side portions for insertion into a concrete wall, said tread, side portions and legs being integrally formed of a core, and a synthetic resin for covering the core, the upper surface of the tread being varied to be inclined upward from the central portion toward the ends thereof at an angle of 1 to 5 degrees and said upper surface of the tread having slip prevention patterns at the entire surface thereof, reflectors provided on the tread at portions adjacent both ends thereof, a wave-shaped grip portion provided on the tread at an inner side thereof in the axial direction and another wave-shaped grip portion provided at a lower surface of the tread in the axial direction, belt-shaped projections formed on the side portions in the axial direction, blow receiving portions formed on the tread at the front ends of the side portions to assist in embedding the legs in a concrete wall, characterized in further comprising contact support pieces provided to protrude from boundary portions between the side portions and the legs capable of contacting the concrete wall.
FIG. 1 is a plan view of a foothold according to the invention;
FIG. 2 is a front view of the foothold in FIG. 1;
FIG. 3 is a side view of the foothold in FIG. foothold 1; and
FIG. 4 is a plan view of a conventional foothold.
A foothold according to a preferred embodiment of the invention is described with reference to FIGS. 1-3.
In FIGS. 1 to 3, a reference numeral 1 depicts an entire configuration of a foothold. The foothold 1 comprises a tread 2, side portions 3 positioned at both sides of the tread 2, and legs 4 embedded in and fixed to a concrete wall. These tread 2, side portions 3 and legs 4 are formed of a core 5 made of iron and have a substantial U-shape as viewed from the plane and a synthetic resin 6 such a polypropylene covers the core 5 for keeping the core 5 from rusting.
The upper surface of the tread 2 is varied in the manner that it is inclined upward from the center S toward both ends thereof at an angle of 1 to 5 degrees. As a result, both feet of a person can be placed on the tread 2 with safety so that the working can be safely performed by the person.
Slip prevention patterns 7 are formed on the entire upper surface of the tread 2 so that a person can go up and down the tread 2 safely even if the person places his or her feet on the tread 2 at any portions thereof.
Reflectors 8 having, for example, red are provided on the tread at portions adjacent both ends thereof, thereby making the presence of the tread 2 clear so that the person can go up and down the tread 2 safely.
A wave-shaped grip portion 9 is provided on the tread 2 at the inner side thereof in the axial direction thereof. Another wave-shaped grip portion 10 is formed on the tread 2 at the lower surface thereof.
In this case, although it is normally conceived that the person goes up and down the tread 2 while gripping the foothold 1 by his or her both hands that is positioned several stages above the foothold 1 on which the feet of the person are placed, the tread 2 can be easily gripped because the wave shape is formed on the inner side of the tread 2 in the axial direction. Still further, since the tread 2 has the wave-shaped grip portion 10 having the irregularities on the lower surface of the tread 2 in the axial direction, both hands can be prevented from slipping so that the person can go up and down the tread 2 safely.
Belt-shaped projections 11 are formed integrally with the synthetic resin 6 on the upper surfaces of the side portions side portions 3 in the axial direction. With the provision of these projections 11, a person can place his or her feet on the tread 2 safely without placing his or her feet on the side portion, thereby providing a reliable foothold 1 enabling the working safely.
Contact support pieces 12 are provided to protrude from boundary portions between the side portions 3 and the legs 4 under the side portions 3 so as to bring into contact with a concrete wall (not shown) such as a manhole wall so that the contact support pieces 12 are brought into contact with the concrete wall to support the foothold 1 when fixing the foothold 1 to the concrete wall, thereby preventing the foothold 1 from hanging downward with more reliability.
Blow receiving portions 13 are formed on the tread 2 at the front ends of the side portions 3 to assist in embedding the legs 4 of the foothold 1 in a concrete wall. When the blow receiving portions 13 is struck, the legs 4 of the foothold 1 are accurately embedded in the concrete wall so as to fix the foothold 1 to the concrete wall without damaging the front of the tread 2.
The synthetic resin 6a for covering the core 5 forming the legs 4 is formed circular in cross section and a plurality of retaining projections 14 are formed on the outer peripheral surface of the synthetic resin 6a and they increase their diameters from the legs 4 toward the side portions 3. The retaining projections 14 are formed integrally with the synthetic resin 6a in plural stages in the axial direction thereof.
With the foregoing construction of the foothold 1, an epoxy resin or the like is filled in holes provided on a concrete wall that is the inner wall of a manhole, then the legs 4 of the foothold 1 are opposed to the holes, thereafter the blow receiving portions 13 are struck by a hammer or the like in a state where the tip end portions of the legs 4 are slightly inserted into the holes so that the legs 4 are sequentially inserted into the holes without receiving a bending moment. As a result, a plurality of retaining projections 14 formed on the legs 4 are brought into intimate contact with the inner peripheries of the holes at the time when the contact support pieces 12 are brought into contact with the concrete wall so as to prevent the legs 4 from being rattled surely in a lateral direction. Since the contact support pieces 12 are brought into contact with the concrete wall to cooperate with the retaining projections 14 when the retaining projections 14 are brought into contact with the holes, the foothold 1 is prevented from being come out and hung from the concrete wall. Consequently, the foothold 1 can be accurately and surely fixed to the concrete wall when the epoxy resin filled in the holes is dried so that the foothold 1 is not hung downward during the use thereof.
According to the foothold of the invention, since the tread, side portions, and legs are integrally formed by the core and the synthetic resin covering the core, the foothold is endurable in use for a long period of time without keeping the core from rusting. Further the upper surface of the tread is varied to incline upward from the center toward both ends thereof at the angle of 1 to 5 degrees, a person can place his or her feet on the upper surface of the tread safely. Still further, the wave-shaped grip portion is formed on the tread at the inner side thereof in the axial direction and another wave-shaped grip portion is formed on the tread at the lower surface thereof, a person can easily grip the tread when the person goes up and down the tread, and these wave-shaped grip portions serve to prevent both hands of the people from being slipped. More still further, since there are provided the slip prevention patterns formed on the entire upper surface and the reflectors provided on the tread at portions adjacent both ends thereof, the belt-shaped projections formed on the side portions in the axial direction, the blow receiving portions formed on the tread at the front ends of the side portions to assist in embedding the legs in a concrete wall and contact support pieces protruding from boundary portions between the side portions and the legs capable of contacting the concrete wall, a person can go up and down the tread safely even if the feet of the person is placed on any portion of the tread.
Further, since the reflectors are provided on the tread at portions adjacent both ends thereof, the reflectors can be easily attached to the tread so as to make the present position of the tread clear, so that a person can go and down the tread safely. Still further, since the belt-shaped projections are formed on the side portions in the axial direction, the working can be safely performed by the person without placing his or her feet on the side portions so that the person can place his or her feet on the tread so as to perform the working. Further, the belt-shaped projections can be easily and firmly integrated with the side portions. More still further, since the blow receiving portions are formed on the tread at the front ends of the side portions to assist in embedding the legs in a concrete wall, the foothold can be efficiently fixed to the concrete wall. Further, the contact support pieces are provided to protrude from boundary portions between the side portions and the legs capable of contacting the concrete wall, the foothold can be fixed to the concrete wall surely without being hung downward even if it is used.
The features disclosed in the foregoing description, in the claims and/or in the accompanying drawings may, both separately and in any combination thereof, be material for realising the invention in diverse forms thereof.

Claims

A foothold (1) for a manhole or the like comprising a tread (2), side portions (3) positioned at both sides of the tread (2), legs 4 connected to free ends of the side portions (3) for insertion into a concrete wall, said tread (2), side portions (3) and legs (4) being integrally formed of a core (5), and a synthetic resin (6) for covering the core (5), the upper surface of the tread (2) being varied to incline upward from the central portion toward the ends thereof at an angle of 1 to 5 degrees and said upper surface of the tread (2) having slip prevention patterns (7) at the entire surface thereof, reflectors (8) provided on the tread (2) at portions adjacent both ends thereof, a wave-shaped grip portion 9 provided on the tread (2) at an inner side thereof in the axial direction and another wave-shaped grip portion (10) provided at a lower surface of the tread (2) in the axial direction, belt-shaped projections (11) formed on the side portions (3) in the axial direction, blow receiving portions (13) formed on the tread (2) at the front ends of the side portions (3) to assist in embedding the legs (4) in a concrete wall, characterized in further comprising contact support pieces 12 provided to protrude from boundary portions between the side portions (3) and the legs (4) capable of contacting the concrete wall.