Magnetic Hydrant Lock

Abstract

A hydrant lock comprising an open-crown bonnet in combination with a closure cap to be seated thereon to enclose the bonnet, with the opening wall and cap base provided with spaced angled bores adapted to be aligned by engagement of teeth on the cap with notches in the crown. A central cylinder integral with the undersurface of the cap top slidably supports a sleeve having extensions pivotally linked to rods disposed in the cap bores adapted to partially enter the crown bores to interlock cap and crown. The cap, cylinder, links and rods are of nonmagnetic material and the sleeve of magnetic material whereby magnetic force applied to the top of the cap raises the sleeve along the cylinder, drawing the rods out of the crown bores to release the cap.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to the field of hydrants which are presently strategically disposed, in the streets of cities, towns and the like, to provide a readily accessible water supply for fire fighting, and for other purposes for which a ready water supply may be required or desired, and has for its specific objective the provision of a closure cap member adapted to enclose and lock the interior of the hydrant to prevent unauthorized access to, and operation of, its valve mechanism, and yet readily and quickly removable by authorized personnel, such as firemen and policemen, by the application to the closure cap member of a strong electromagnet, whereby the magnetic lines of force operate to shift the positions of the internal locking members to release the closure cap from the hydrant. Such release of the closure cap can be accomplished only by the application thereto of an electromagnet connected to a suitable source of electric current, such as the battery of a fire truck, and it is obvious that such equipment will not readily be available to unauthorized persons. A further deterrent to unauthorized and unlawful access to the internal mechanism of the hydrant is provided by the disposition of the top of the hydrant bonnet flush with the top of the operational valve nut, so that only a special kind of socket wrench can operate the nut, once the closure cap has been removed.

2. Prior Art

As presently constituted, hydrants in general use all employ a valve nut, usually hexagonal in shape, which projects above the top of the hydrant proper and is rotated to open the valve for the discharge of water from the hydrant. This nut can be turned with the use of any standard type of regular or monkey wrench. As a consequence hydrants are constantly being operated illegally by unauthorized persons, vandals and even by children, with consequent damage. Further, since the operating nut is constantly exposed to the elements, dirt and grime tend to accumulate in the surrounding crevices and, in inclement weather, rain and snow accumulate therein and thereafter turn into ice, thereby freezing the nut and preventing operation, which, in emergencies, can have serious consequences.

Numerous attempts have been made in the past to overcome these disadvantages. For example, in U.S. Pat. No. 2,118,233, there has been proposed a guard for the operating nut comprising a bolted annular cap. In U.S. Pat. No. 2,699,176, a protector plate has been provided over the operating nut, likewise secured by bolts. In U.S. Pat. No. 2,869,576, there has been provided a circular skirt member, operative by means of a key. Each of these devices is easily removable by unauthorized persons, with the use of ordinary tools, and hence have not solved the problem of preventing unlawful access to the hydrants. Similarly, in U.S. Pat. No. 2,762,386, an antifreeze cap has been provided to protect the operating nut from the elements, but this, too, has its disadvantage, since it is secured to the hydrant with a screw and easily removable with an ordinary screwdriver.

In short, the prior art has failed to provide a hydrant guard or lock which is both protective to the operating mechanism from exposure to the elements and consequent damage, as well as impervious to attack and removal by unauthorized persons equipped with mechanical tools.

BRIEF SUMMARY OF THE INVENTION

The aforementioned difficulties and disadvantages are overcome by the present invention, which provides a closure cap member for the hydrant which locks internally to the hydrant bonnet, thereby fully protecting the interior of the hydrant, and which can be unlocked therefrom only by the application of magnetic force to the top of the cap, whereby the attraction of the magnetic lines of force causes withdrawal of the internal locking members from interengagement and thereby releasing the cap member for removal. While the objects and advantage of the present invention are many, some of the more important ones should be mentioned.

It is therefore the principal object of my invention to provide a hydrant lock having a closure cap which is internally locked to the hydrant bonnet and releasable only by the external application of magnetic force.

A second important object of my invention lies in the provision of a hydrant lock having a closure cap which is fully protective of the internal mechanism of the hydrant from the elements.

A third important object of the invention lies in the provision of a hydrant lock which is tamperproof, and cannot be opened with the use of mechanical tools.

A fourth important object of my invention lies in the provision of a hydrant lock which is so disposed as to prevent access to the operating nut, even after removal of the closure cap, except with a special type of socket wrench.

Still another important object of my invention lies in the provision of a hydrant lock which is readily adapted for use with and upon present types of hydrants.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other salient objects, advantages and functional features of my invention, together with the novel features of construction, composition and arrangement of parts, will become more readily apparent from an examination of the following specification, taken with the accompanying drawings, wherein:

FIG. 1 is a side view of a preferred embodiment of my invention;

FIG. 2 is an enlarged cross-sectional view, taken on the lines 2--2 of FIG. 1;

FIG. 3 is a view similar to FIG. 2, but showing removal of the closure cap by the employment of an electromagnet;

FIG. 4 is a cross-sectional view, taken on the lines 4--4 of FIG. 2;

FIG. 5 is a view similar to FIG. 4, but showing the withdrawal of the engaging rods of the closure cap from the hydrant bonnet;

FIG. 6 is a further enlarged cross-sectional fragmentary view showing the seating engagement of the closure cap teeth in the slots of the bonnet crown;

FIG. 7 is a side view similar to FIG. 1, partly broken away and with the closure cap removed, showing engagement of a socket wrench with the valve nut;

FIG. 8 is a side view of a modified embodiment of by invention in relationship with a present form of hydrant;

FIG. 9 is a view similar to FIG. 8, but showing the modified embodiment welded to the hydrant bonnet; and

FIG. 10 is an enlarged cross-sectional view, taken on the lines 10--10 of FIG. 9.

Similar reference characters designate similar parts throughout the different views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Illustrative of the embodiment of FIGS. 1-7 my hydrant lock 10 comprises a circular cap member 12 removably cooperative with a bell-shaped base member or bonnet 14 mounted upon and locked to the standpipe or barrel 16 of the hydrant, the latter containing the usual axially rotative valve shaft 18 for the control of water leading from a water main through a discharge pipe in the hydrant, the flow of which is controlled by the rotation of a hexagonal nut 20 secured to the top of the shaft 18, the shaft 18 being rotatively mounted in a bushing 22, as by rivets 24, the bushing 22 secured to a support member 26, as is well known in the art. Sine the present invention is restricted to the hydrant lock 10 alone, further details concerning the structure and operation of the hydrant are omitted, as they are well covered by existing art.

Referring now to FIGS. 2 and 3, the bonnet 14 is hollow and is provided with a central circular opening 28 at the top thereof, the upper edge of which is on a line parallel with the top surface of the hexagonal nut 20, as shown in FIG. 3. The wall 30 of the opening 28 is vertical and is provided with a series of equally spaced bores 32 angled therein and opening into the surface of the wall 30, and with a series of equally spaced notches 34 therein which open onto the outer surface of the bonnet 14, the wall 30 having alternate bores 32 and notches 34 around its circumference.

The cap member 12 defines central chamber 36 and is provided with a circular base 38 of reduced diameter, thereby forming an annular lip 40, the outer diameter of the base 38 being slightly smaller than the diameter of the opening 28, whereby the base 38 fits into the opening 28 snugly, with the lip 40 in seated engagement with the outer surface of the bonnet 14, as shown in FIG. 2, to form a tight enclosure for the interior of the hydrant.

The base 38 is of larger cross section that the rest of the cap 12, preferably triangular in cross section, and is provided with a series of equally spaced bores 42 angled therethrough, opening both into the inner and outer surfaces of the base 38, the bores 42 adapted to come in registry with the bores 32 in the wall 30 to define elongated bores when the cap 12 is seated on the bonnet 14, as shown in FIG. 2. The outer surface 44 of the base 38 is further provided peripherally with a series of equally spaced teeth 46 which are adapted to come into registry with and fit into the notches 34 in the wall 30 of the bonnet 14, as shown in FIG. 6, so that when the cap 12 is placed upon the bonnet 14 and rotated until the teeth 46 come into registry with the notches 34 the cap 12 will seat upon the bonnet 14 with the respective bores 32 and 42 in registry and aligned, as shown in FIGS. 2 and 5.

A hollow cylinder 48 is provided integral with the interior surface 50 of the cap 12, and is adapted to loosely enclose the hexagonal nut 20 when the cap 12 is seated on the bonnet 14, as shown in FIG. 2. A sleeve 52 is slidably mounted on the cylinder 48 and is prevented from slipping off by an elastic O-ring 54 which is mounted on the cylinder 48 near its base, thereby permitting a range of sliding movement of the sleeve 52 along the cylinder 48, for the purposes which will hereinafter be disclosed, The sleeve 52 is provided with a series of equally spaced and integral extensions 56, which are equal in number to, and radially disposed to align with, the respective bores 42 in the base 38, and rods 58 are pivotally connected to the extensions 52 by means of intermediate links 60, the rods 58 having an outer diameter slightly smaller than the internal diameter of the bores 32 and 42, thereby permitting the rods 58 to move freely into and out of the respective bores, but not too loosely, the links 60 affording the rods 58 angular disposition with respect to the extensions 56 as the position of the sleeve 52 on the cylinder 48 varies, as will be seen.

The critical features of my invention involve the nature of the materials or composition thereof, since the locking and unlocking of the cap member 12 to and from the bonnet 14 is dependent upon magnetic attraction, for which purpose an electromagnet 62 is required, as shown in FIG. 3, applied to the top of the cap member 12. For this reason the cap member 12, including its central cylinder 48, and the rods 58 and links 60, are made of a nonmagnetic material, either a metal such as aluminum, or a plastic or other type of nonmagnetic synthetic material, while the sleeve 52 with its extensions 56 are composed of a highly magnetizable material, such as iron, which quickly loses its magnetic properties when the magnetic lines of force of a magnet are withdrawn or killed. The structural composition of the remainder of the hydrant, including the bonnet 14, is immaterial, since it will in no way be affected by the application of the electromagnet 62 to the cover 12.

While there are many suitable types of electromagnets on the market today, which may be equally operative with my invention, I have found that an electromagnet manufactured by Eriez Magnetics, of Erie, Pa., under the trademark "Selecto," model "SL" to be particularly effective and adequate for the purposes of the invention, since this model may be connected to a 12 v. or 115 v. power source for activation. Such an electromagnet may be made available to every firetruck as part of its regular equipment.

In the operation of my invention, the cap member 12 is normally locked to the hydrant, as shown in FIG. 2, with the hydrant interior thereby closed off and protected from the elements. In case of fire and the need for access to the hydrant water supply, an authorized person, such as a fireman, removes the electromagnet from the firetruck and places it upon the top of the cap 12, and then connects the electromagnet line to the truck battery, and activates the electromagnet. Its magnetic lines of force reach the sleeve 52 through the nonmagnetic cover of the cap 12, causing the sleeve 52 to be drawn to the top of the cylinder 48, thereby drawing the rods 58 out of engagement in the bores 32, as shown in FIG. 3. The cap member 12 can then be lifted off the bonnet 14. In this embodiment it is to be noted that the hexagonal nut 20 is disposed below the upper surface of the opening 28, and hence cannot be reached with an ordinary type of wrench, but requires the use of a special type of socket wrench 64, such as shown in FIG. 7, the socket portion being internally hexagonal to fit the nut 20.

When the hydrant is no longer required the cap member 12 is once again locked to the bonnet 14 by placing the cap 12 upon the bonnet 14 and rotating it until the teeth 46 come into registry with the notches 34, whereupon the cap 12 will drop into place with the bores 42 aligned with the bores 32. The power source for the electromagnet is then cut off and the demagnetized sleeve 52 will drop down on the cylinder 48, causing the rods 58 to enter the bores 32, thereby locking the cap 12 once again to the bonnet 14, as shown in FIG. 2.

Coming now to the modified embodiment shown by FIGS. 8, 9 and 10, my invention can be applied to existing forms of hydrants, in which the bonnet 14' is mounted on the barrel 16 and the hexagonal nut 20 extends openly above its surface. In this modification there is provided a crown 70 which is welded to the bonnet 14' as at 72, as shown in FIG. 9, thereby to form a base member 74 which is the equivalent of the bonnet 14 in FIG. 1, with the cap member 12 and its internal structures identical with the cap member 12 and internal structures of FIGS. 1-7, as shown in FIG. 10. The crown 70 is provided with bores 76 and notches 78 in the same manner as has heretofore been described, to correspond with the respective bores 42 and teeth 46 of the cap 12.

In this embodiment it is to be noted that the crown 70 is of a reduced height, so that when the cap 12 is removed the hexagonal nut 20 extends above the surface of the crown 70 and is therefore operative with any standard type of wrench. However, if it is desired the crown 70 may be of greater height so that the top of the crown 70 is on a plane parallel with the top of the hexagonal nut 20, thereby requiring in such modification the special type of socket wrench 64 as is required with the embodiment of FIGS. 1-7.

From the foregoing it is obvious that the embodiments shown and described are by way of illustration and not of limitation, and that various changes may be made in the construction, composition and arrangement of parts without limitation upon or departure from the spirit and scope of the invention, or sacrificing any of the advantages thereof inherent therein, all of which are claimed.

Claims

Having described my invention, I claim:

1. In association with a hydrant of the type described, a hydrant lock comprising a hollow bonnet provided with a crown having a central opening therein defining a peripheral wall provided with a plurality of spaced bores angled therein alternate with a plurality of spaced notches, in combination with a closure cap adapted to be seated upon the crown to close the opening, the closure cap being hollow and provided with a base of reduced outer diameter adapted to fit into the crown opening and thereby to define an annular lip adapted to abut the rim of said opening, the base of the cap provided with a plurality of spaced bores angled therethrough, and disposed to align with the crown bores, alternating with a plurality of spaced teeth disposed around the outer periphery of the base and adapted to be engaged in the crown notches when the cap is seated upon the crown, to align the respective bores, a hollow cylinder centrally secured to the undersurface of the cap top and depending therefrom, a sleeve slidably mounted on the cylinder and provided with spaced extensions corresponding to the base bores, radially extending means within the cap comprising a rod slidably disposed within each base bore and a link pivotally engaging each rod to one of said extensions, the rods adapted to partially enter the crown bores when said bores are aligned with the base bores, to interlock the cap to the crown, and means to retain the sleeve upon the cylinder, said interlocking rods being magnetically releasable from the crown bores.

2. A hydrant lock as described in claim 1, the means to retain the sleeve upon the cylinder comprising an elastic ring secured around the cylinder below the sleeve.

3. A hydrant lock as described in claim 2, the cylinder being of a length to loosely enclose the operating nut of the hydrant.

4. A hydrant lock as described in claim 3, the closure cap, cylinder, rods and links composed of a nonmagnetic material and the sleeve composed of a highly magnetizable material.

5. A hydrant lock as described in claim 4, the top of the crown disposed on a plane parallel with the top surface of the operating nut of the hydrant.

6. A hydrant lock as described in claim 4, the top of the crown disposed on a plane below the top surface of the operating nut of the hydrant.

7. A hydrant lock as described in claim 4, the nonmagnetic material being aluminum and the magnetizable material being ferrous.

8. A hydrant lock as described in claim 4, the nonmagnetic material being plastic and the magnetizable material being ferrous.

9. A hydrant lock as described in claim 4, the hydrant crown being unitarily distinct from the rest of the bonnet and adapted to be welded thereto.