Road structure – process – or apparatus – Pavement – Vault cover-closure
Patent
1985-04-17
1987-01-20
Leppink, James A.
Road structure, process, or apparatus
Pavement
Vault cover-closure
52 19, E02D 2914
Patent
active
046377522
DESCRIPTION:
BRIEF SUMMARY
This invention relates to manhole access covers of the kind in which a removable cover member fits within an outer frame, the cover member itself being fabricated as a frame (hereinafter referred to as the inner frame) which is filled with concrete or other appropriate material.
The object of the invention is to provide an access cover whose outer and inner frames can be produced econcmically.
According to the invention, an access cover has outer and inner frames each of which is fabricated from a plurality of angle members joined to each other at the corners of the frame, the joint at each corner including a corner member extending around the corner and to which the angle members at each corner are crimped by piercing metal out of the angle members and crimping it into the corner members.
Other advantageous features of the invention will become apparent from the ensuing description of one construction of manhole access cover in accordance with the invention and shown in the accompanying drawings.
Fig. 1 is an exploded perspective view showing the manner of assembly of the outer frame at the corners of the frame,
FIG. 2 shows a side elevation of an assembled corner of the outer frame.
FIG. 3 is a section on the line III--III of FIG. 2 and shows schematically the manner in which the outer frame is crimped at a corner,
FIG. 4 is an exploded perspective view showing the manner of assembly of the inner frame at a corner,
FIG. 5 shows a side elevation of an assembled corner of the inner frame,
FIG. 6 is a section on the line VI--VI of FIG. 5 and shows schematically the manner in which the inner frame is crimped at a corner,
FIG. 7 is a plan view of a manhole access in which two cover members are mounted in a common outer frame,
FIG. 8 is a section on the line VIII--VIII of FIG. 7,
FIG. 9 is a fragmentary side view of the inner surface of the inner frame showing the mounting of a lifting block,
FIG. 10 is a section on the line X--X of FIG. 7, and
FIG. 11 is a section on the line XI--XI of FIG. 7.
Referring now more particularly to FIGS. 1 to 3 of the drawings, the manhole access cover has an outer rectangular frame formed from four lengths of angle member 1 formed as aluminium extrusions and joined to each other at the corners of the rectangle. Each angle member has a limb 2 which in use of the outer frame extends substantially horizontally and a limb 3 which in use extends substantially vertically; thus the finished frame has a continuous substantially vertical wall and a continuous substantially horizontal ledge extending inwardly from the vertical wall. On the outer surfaces of the limbs 2 and 3 are provided a series of ribs which define between them a series of grooves or slots. Some of the ribs are formed with flanges at their free ends which flanges overlie the adjacent grooves to provide, so to speak, captive grooves. Thus as shown in FIG. 1 the grooves 4, 5, 6 and 7 are captive grooves. The grooves 4 are provided in the lower part of the vertical wall.
Prior to joining two angle memebrs 1 together at a corner their ends are first mitred. The two angle members 1 are then brought together as indicated by the arrows in FIG. 1 and at the same time an angular corner plate 8 and an angular corner member 9 are located so that they slide into the grooves 4 and 5 respectively of the two angle members 1. Thus the corner members 9 extend widthwise only part way up the vertical wall substantially from the lower edge thereof. After assembly of the outer frame in this way, it is placed in a crimping machine in which as shown in FIG. 3 an anvil 11 locates in each corner of the frame and a crimping tool 12 is applied to the outside of the frame.
The corner members 9 have on both their inner and outer surfaces a series of vertical grooves 13, the grooves side walls 14 nearer the ends of the corner members 9 sloping as a ramp to the top of the groove as best seen in FIG. 3. When the crimping tool 12 is applied it pierces tongues 15 out of the flanges 16 and bends them into the grooves 13 in the corner member 9 to engage a
REFERENCES:
patent: 2101349 (1937-12-01), Sharp
patent: 2877696 (1959-03-01), Elkington
patent: 3797194 (1974-03-01), Ekstein
patent: 3975870 (1976-08-01), Naka
patent: 4443973 (1984-04-01), Naka
patent: 4498804 (1985-02-01), Ferns
Leppink James A.
Smith Matthew
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