Locking means for electric meters

Abstract

To prevent unauthorized access to an electric watt-hour meter, a yoke is provided to enclose the lugs at the ends of the usual U-section split ring retaining band used to fix the receptacle for the meter works such as glass bowl enclosure therefor, to the meter base. A bolt-type lock goes through four aligned holes in the lugs and in the yoke and has transversely extensible locking members standing out beyond the fourth hole to prevent withdrawal of the bolt until unlocked. An enlarged end or head on the bolt prevents movement of the bolt in one direction, and a hood on the yoke prevents access to the other end and the locking members.

Description

This invention proposes to stop the theft of electric current effected by reversal or by-passing of the watt-hour meter or other nefarious methods which require access to the interior of the meter. In the commonest type of meter, the meter works are held to their housing or base by a steel split ring of U-section encircling and embracing matching and meeting flanges on the meter and its base; or flanges on the base and on a transparent bowl enclosing the works have been similarly united. A simple screw with a head on one end and a hole in the other has been the sole closure means for the ring, being put through aligned holes in the terminal lugs at the ends of the split ring and protected merely by a wire seal. Thus the whole ring can be removed with a screw driver. The seal is just a moral deterrent.

A secure locking device for the common meter has not been available up to now to combat the widespread practice of pilfering electric current.

To provide greater security against such theft of current, we have devised the improved locking ring disclosed herein and shown in the accompanying drawings, in which:

FIG. 1 shows the meter in assembled working relation on its base or housing, with the novel locking yoke securing the split ring against unauthorised removal.

FIG. 2 is an enlarged plan view of the yoke and adjacent portions of the split ring shown in FIG. 1.

FIG. 3 is an end elevation of the yoke of FIGS. 1 and 2, without the locking bolt.

FIG. 4 is a side elevation of the parts shown in FIG. 2.

FIG. 5 is a vertical section on line 5--5 of FIG. 4.

FIG. 6 is a vertical section on line 6--6 of FIG. 5.

FIG. 7 shows the U-section split locking ring in plan.

FIG. 8 is a transverse section of the ring of FIG. 7 on line 8--8 of FIG. 7.

FIG. 9 is a section on line 9--9 of FIG. 2 showing in detail the uniting of the transparent bowl of the meter works with the base or housing by means of the split ring.

Having reference to the drawings, the split locking ring 1 is made in U-section of fairly thick (0.060 inches) steel stock, anti-corrosion plated, and hardened for stiffness, with integral lugs 3 formed by bending the ends of the split circle radially outward after reducing the height of the flanges of the U-section as indicated at 5 to facilitate bending the lugs outwardly to stand out nearly radially and parallel to each other when the ring is in place on the meter with the clamping screw 7 in place. The internal width of the U portion is such as to receive easily the combined thickness of the portions 23, 25 of the metal rim 13 of the glass bowl of the meter works and the flange 21 of the meter base when juxtaposed as shown in FIGS. 6 and 9. The continuation of the flanges in lowered form on the lugs 3 stiffens the lugs against distortion by tamperers.

As noted, FIG. 1 shows the complete meter assembly, this being of the common type in which the works are mounted on a circular non-conducting plate 9 to which is secured the transparent bowl 11 of glass by the metallic rim 13 overlying the bead 15 on the rim of the bowl 11. The meter base or housing 17, FIG. 1, is of sheet metal, and contains the sockets (not shown) in which the symmetrically disposed contacts (not shown) projecting from the plate 9 are engaged to complete the circuits through the meter. This box-shaped base has a circular opening defined by an extruded neck 19 terminating in the radially extending flanges 21 on which the plate 9 carrying the works is mounted.

As heretofore, the split ring 1 unites the bowl to the flange 21 of the box-like base or housing 17 by embracing within its U-shaped channel 16 the flange 21 on the base and the radially and axially and axially extending portions 23,25 of the rim 13 (FIG. 9).

In accordance with the invention, one lug 3 of the split ring 1, made as described above, is formed with an extruded hole 27, necked and internally threaded, to be engaged by clamping screw 7 loose within an opposite hole in the other lug 3. A neoprene washer 29 on the screw and between the two lugs prevents loss of the screw in shipment and handling. The conical entrance to the threaded hole 27 resulting from the broaching operation in forming hole 27 up proper threading of the screw into the opposing lug. Installation of the split ring 1 is effected as usual by enlarging the ring manually by spreading the lugs and placing it about the rim 13 and flange 21, and inserting and tightening screw 7 in hole 27.

Further in accordance with the invention, the lugs 3 and the clamping screw 7 are guarded against unauthorized access by a malleable cast-iron unbreakable 31 having a pocket or chamber 33 therein to receive and enclose completely the lugs 3,3 and the clamping screw 7. The interior walls of the chamber converge at the bottom to slightly more than the space occupied by the lugs 3,3, as seen in FIG. 5, and holes 35 and 37 are formed in its walls to receive a key-operated cylindrical bolt-type lock 40 such as that of our U.S. Pat. No. 3,714,802, which passes through holes 41 in the lugs 3,3. Radially extensible locking balls 43 are extruded from the shank of the bolt 40 after it is passed through the far hole 37 in the yoke 31.

An integral part of the casting forms a hood 45 completely enclosing the end of bolt 40 and prevents access to the locking balls 43, and prevents the application of hammer blows or other force to this end of this bolt, while the head end of the bolt is sunk in the thick wall of the yoke for nearly its entire length, within hole 35, thus leaving no substantial part of the length of bolt 40 accessible for the application of force.

To render prying force unavailing, the yoke has wings 51 of U-section to receive the split ring 1, each extending 5.degree. to 10.degree. around the circuit of the ring. Within the channel of the U formed in each wing 51 is an integral cross-bar 53 which forms a shoulder that effectively blocks the entry of a chisel or other 1 and the yoke. Thus this sole potentially available point of attack on the improved meter lock is eliminated.

The bolt-type lock 40 being proof against picking by any means short of reproducing its complex and costly key, the invention device has proved able to withstand all attacks short of wreckage by sledge-hammer tactics. Damage to the lock through tampering is met by merely replacing the lock itself.

While we have illustrated and described one form in which the invention may be embodied, we are aware that many modifications may be made therein by any person skilled in the art, without departing from the scope of the invention as expressed in the claims. Therefore, we do not wish to be limited to the particular forms shown, or to the details of construction thereof, but

Claims

What we claim as our invention is:

1. Locking means for electric meters having in combination a base, a receptacle holding the meter works, a U-section split ring uniting the base and the receptacle, means on the ends of the split ring to contact the ring, unbreakable means shielding the contracting means from access, and key-operated means locking the shielding means to the split ring.

2. The combination according to claim 1 in which the key-operated means also locks the split ring from opening.

3. The combination according to claim 1 in which the key-operated locking means is substantially wholly enclosed in the shielding means.

4. The combination according to claim 1 in which there are lugs on the ends of the split ring, screw means drawing the lugs toward each other, and the shielding means is a yoke enclosing the lugs and the screw means preventing access thereto.

5. The combination according to claim 4 in which the key-operated locking means locks the yoke to the lugs.

6. The combination according to claim 4 in which U-section portions of the yoke receive parts of the split ring adjacent the lugs, and there is a shoulder within each U-section portion formed by an integral cross-bar spaced inward from the end of such U-section portion.