AU738820B1 - Foothold for a manhole or the like - Google Patents

Description

Our Ref:7511260 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Applicant(s): Miyama Kogyo Kabushiki Kaisha No 4-5, Sakaecho 2-chome Soka-shi Saitama-ken 340-0011 Japan Address for Service: Invention Title: DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 Foothold for a manhole or the like The following statement is a full description of this invention, including the best method of performing it known to me:- 5020

SPECIFICATION

FOOTHOLD FOR A MANHOLE OR THE LIKE BACKGROUND OF THE INVENTION 1. Field of the Invention: The 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.

2. Description of the Related Art: The applicant has U.S. Patent No. 5, 967,256 which has been issued October 19, 1999 and now known as shown in Fig. 4 wherein a foothold 21 for a manhole comprises a tread 22, side portions 23 positioned at both sides of the tread, legs 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 corneredportions between the tread 22 and the side;portions:23, a wave-grip 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 provided on the side portions 23 along the outer end portions in the axial direction, and blow receiving portions 33 provided on the tread at the front end side of the tread 22 to assist in embedding the foothold 21 for a manhole in a concrete wall.

However, in this foothold 21 for a manhole, since the reflectors 28 are provided at the cornered portions between the tread 22 and the side portions 23, the belt-shaped projection 31 are forced to be provided on the end portions or outer sides of the side portions 23, while entrance grooves 35 are needed to be formed between the front ends of the side portions 23 and the front ends of the belt-shaped projections 31 for attaching the reflectors 28 on the cornered-portions between the tread 22 and the side portions 23, it is not easily to integrally form the tread 22, the side portions side portions 23, the legs 24 and the core 25 by the synthetic resin 26. Further, the strength of fixation of the belt-shaped projections 31 relative to the side portions 23 becomes weak, and the blow rrwMuoaSWYRbc467II =cyc&O. Aama'1 -2receiving portions 33 are not provided at the front ends of the side portions 23 owing to the presence of the reflectors 28, thereby arising a problem that the foothold 21 is not efficiently struck to be embedded in the concrete wall.

According to one aspect of the present invention there is provided a foothold for a manhole or the like, the foothold including a tread portion which, when the foothold is in its normal in-use orientation have an upper side, a lower side, an inner side and an outer side, a side portion at each end of said tread portion, said side portions extending laterally with respect to the tread portion, each side portion including a free end, a leg operatively connected to each free end of each side portion, said legs being adapted for insertion into a concrete wall, said tread portion, side portions and legs being integrally formed of a core and a synthetic resin for covering the core, the upper surface of the upper side being inclined upwardly from a central portion towards each end at an angle of 1 to 5 degrees, said upper surface having a slip prevention pattern thereon, the foothold further including reflectors, and blow receiving portions on the tread portion, a generally wave-shaped grip portion on the tread portion on the inner side thereof extending in the axial direction thereof, and a further wave-shaped grip portion on a surface of the lower side of the tread portion extending in the axial direction thereof upwardly extending projections each being disposed on one side of each side portion and extending generally in the axial direction thereof, contact support pieces protruding from boundary portions between the side portions and the legs for contacting the concrete wall, said reflectors being provided on the outer side of the tread portion at positions adjacent both ends thereof and between the slip prevention patterns, said blow receiving means provided to assist in embedding the legs into the concrete wall.

Preferred embodiments of the invention will be hereinbefore described with reference to the accompanying drawings, and in those drawings: FIG- 1 is a plan view of a foothold for a manhole or the like 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. 1; and (KTrfnnri I UCT'q'1 cTtR va 7 Tof I, fT Tn on /IfT n n~ r Ir rii nllrlr FIG. 4 is a plan view of a conventional foothold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A foothold for a manhole or the like 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 upper surface of 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 conspicuous color, e. red are provided on the tread at portions adjacent both ends thereof within theside portions 3 between the slip prevention patterns 7, 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 provided 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 portions 3, 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 provided on the tread 2 at the fronts 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 are 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 or the like 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 provided 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 provided 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. As a result, a plurality of retaining projections 14 provided 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 be inclined 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 within the side portions between the slip prevention patterns, the beltshaped projections provided on the side portions in the axial direction, the blow receiving portions provided on the tread at the fronts 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 are placed on any portion of the tread.

Further, since the reflectors are provided on the tread at portions adjacent both ends thereof within the side portions between the slip prevention patterns, 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 provided 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, since the position where the reflectors are fixed to the tread is inside the side portions, the beltshaped projections can be easily and firmly integrated with the side portions.

More still further, since the blow receiving portions are provided on the tread at the fronts 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 reference numerals in the following claims do not in any way limit the scope of the respective claims.

P:\WPDOCS\MCC\COMPRISE 18/7/00 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such-as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (2)

1- A foothold for a manhole or the like, the foothold including a tread portion which, when the foothold is in its normal in-use orientation have an upper side, a lower side, an inner side and an outer side, a side portion at each end of said tread portion, said side portions extending laterally with respect to the tread portion, each side portion including a free end, a leg operatively connected to each free end of each side portion, said legs being adapted for insertion into a concrete wall, said tread portion, side portions and legs being integrally formed of a core and a synthetic resin for covering the core, the upper surface of the upper side being inclined upwardly from a central portion towards each end at an angle of 1 to 5 degrees, said upper surface having a slip prevention pattern thereon, the foothold further including reflectors, and blow receiving portions on the tread portion, a generally wave-shaped grip portion on the tread portion on the inner side thereof extending in the axial direction thereof, and a further wave-shaped grip portion on a surface of the lower side of the tread portion extending in the axial direction thereof, upwardly extending projections each being disposed on one side of each side portion and extending generally in the axial direction thereof, contact support pieces protruding from boundary portions between the side portions and the legs for contacting the concrete wall, said reflectors being provided on the outer side of the tread portion at positions adjacent both ends thereof and between the slip prevention patterns, said blow receiving means provided to assist in embedding the legs into the concrete wall.

2. A foothold substantially as hereinbefore described with reference to the accompanying drawings. Dated this 9th day of August, 2001 MIYAMA KOGYO KABUSHIKI KAISHA By Its Patent Attorneys DAVIES COLLISON CAVE \S 34 Cnnra- UnCoTqqr--% C'JTAV(7 CAR7 7079 7 TQ-M O^Ti T TA on/nT