US1955018A - Safety device for manhole covers - Google Patents

Description

April 17, 1934. c. E. REGO 1,955,018

SAFETY DEVICE FOR MANHOLE COVERS Filed Feb. 2, 1933 q Fig.3. a) 3 o 971% ,L 231' venior:

ab 5'0 '30 CMTMERsgg/ H L l i 6-1345 64:; (5 131; @WWM Patented Apr. 17, 1934 UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to safety devices for manhole covers and particularly for the covers of manholes in which gases are liable to accumulate and cause an explosion when an electric current therein becomes short circuited.

One object of the invention is to limit the upward movement of the cover when an explosion occurs within the manhole.

Another object is the provision of means for designating in a service station the particular manhole in which an explosion has occurred.

These objects are attained by the mechanism illustrated in the accompanying drawing.

v For the purpose of illustrating the invention,

one preferred form thereof is illustrated in the drawing, this form having been found to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized, and the invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described except as required by the scope of the appended claims.

' Of the drawing Figure 1 represents a plan of a manhole seat and cover therefor.

Figure 2 represents a vertical section of same on line 2, 2, on Fig. 1, and

Figure 3 represents a diagram showing a plurality of manholes electrically connected to an annunciator in a service station.

Similar characters indicate like parts throughout the several figures of the drawing.

In the drawing, represents an annular seat having a depression 11 therein to receive a man hole cover 12.

The cover 12 is adapted to close a manhole 13 which has recesses 14 formed in the side wall 40 thereof.

In each one of these recesses 14 is disposed a tubular member 15, the upper end of which is secured to the annular seat 10.

Each tubular member 15 has a partition 16 therein and the lower end of each tubular member 15 is provided with a closure 17.

Above the closure 17 and below the partition 16 is a piston 18 adapted to reciprocate endwise of said tubular member 15.

Between the partition 16 and piston 18 is a helical spring 19 and just beneath each partition 16 is a filling plug 20.

By removing this filling plug 20 the space between the partition 16 and piston 18 may be filled 5 with alemite or some similar lubricant, this lubricant keeping the spring 19 and piston 18 in workable condition at all times.

The piston 18 is threaded to the lower end of a rod 21 extending upwardly through the partition 16 and having at its upper end a headed nut 22 extending through the cover 12, the head of each nut 22 being disposed in a depression 12 in said cover.

The piston 18 may be adjusted lengthwise of the rod 21 to vary the tension of the spring 19 and then locked in adjusted position by means of the nuts 23, 24.

The closure 17 may be adjusted to vary the downward movement of the rod 21.

Surrounding each tubular member 15 are a plurality of anchors 25 extending outwardly between the bricks forming the walls of the manhole, thereby preventing any upward movement of the tubular member 15, these tubular members 15 having been disposed within the recesses 14 formed in the wall of the manhole.

The recesses 14 are closed by concrete 14 leaving the cylindrical wall to the manhole free from all protuberances extending into the manhole.

This is of some advantage as it prevents any injury to the workmen within the manhole.

One of the tubular members 15 is provided with a switch 26 which may be of any well known construction and includes a movable member 27 in the path of a disk 28 secured to the rod 21.

This switch 26 is in an electric circuit 26 provided with a battery 29 and has a signal such as a lamp 30 in the circuit.

When an explosion takes place within the manhole, the cover 12 will be raised from its seat 10 a limited distance, the springs 19 being compressed during this upward movement of the cover 12.

During the lifting of the cover the gas within the manhole will escape and then the springs 19 will return the cover 12 to its normal position.

During the lifting of the cover 12 the disk 28 will operate the movable member 27 of the switch 26 and close the electric circuit 26 to the signal lamp 30.

This lamp 30 may be located at any convenient point as in a service station.

Preferably the lamp 30 is one of a plurality of lamps on an annunciator 31 and each lamp on the annunciator is electrically connected with a different manhole safety device.

By means of this construction whenever an explosion occurs in any particular manhole, a warning is given in the service station and the particular manhole in which the explosion occurs is indicated on the anmmciator 31.

By this system the service station is warned whenever an explosion occurs and identification is made as to the particular point where the trouble occurs.

By use of this system the service man can quickly get to the point where the trouble has occurred and make the necessary repairs.

When access is desired to the interior of the manhole, the headed nuts 22 threaded to the upper ends of the rods 21 may be removed and the cover 12 displaced from its seat 10.

The cover 12 has laterally extending projections 32 which rest in recesses 33 in the seat 10 and when these projections 32 are positioned within the recesses 33 the nuts 22 will always be in register with the rods 21 within the tubular members 15.

The switch 26 is so constructed that, when once closed by the upward movement of the disk 28, it will remain closed until the service men reach the manhole 13 and make the necessary repairs, it being then returned to its normal position by one of said service men.

It is believed the operation and many advantages of the invention will be understood readily without further description.

Having thus described my invention, I claim 1. In a device of the class described, the combination of a manhole cover; an annular seat therefor; a plurality of tubular members depending from said seat, each having a partition therein; a piston beneath said partition; a rod to which said piston is connected, the upper end of said rod being connected to said cover; and a spring surrounding said rod between said partition and piston.

2. In a device of the class described, the combination of a manhole cover; an annular seat therefor; a plurality of tubular members depending from said seat, each having a partition therein; a piston beneath said partition; a rod to which said piston is connected, the upper end of said rod being connected to said cover; and resilient means between said partition and piston.

CHARLES E. REGO.

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