Non-reusable Locking Device And Method Of Use

Abstract

A case hardened bolt is provided with a case hardened nut which can easily be hand threaded onto it. The shank of the bolt above a threaded portion of approximately the width of the bolt is of a reduced diameter such that the nut can turn freely with respect to the bolt. This portion of reduced diameter is at least as long as the width of the nut. In use, the bolt is passed through at least two hasps which are to be locked in position with respect to each other; the nut is threaded onto the bolt to have position in alignment with the portion of reduced diameter; and the threads on the bolt immediately adjacent the nut are deformed using a hammer and blunt chisel or the like, thus making it impossible for the nut to be removed from the bolt. When it is desired that the hasps be unlocked with respect to each other, the bolt is destroyed by using a bolt cutter on the shank, and the shank portions are removed from the hasps.

Description

BACKGROUND OF THE INVENTION

This invention relates to locking devices which must be destroyed to release them. Specifically, it relates to a locking device and a method for using the locking device particularly applicable for sealing railroad cars from the time they are loaded with cargo until that cargo reaches its predetermined destination for unloading.

Loss of goods being transported in supposedly sealed box cars from one part of the country to another is an exceedingly great problem with rail shipments today. The present substantially universal system of applying frangible seals to box car doors at the time they are initially loaded serves only to prove or at least indicate that a box car door has not been opened between the time the seal is set and the time the seal is broken. This system does not serve as a physical deterrent to entry into the box car by opening the door, inasmuch as the seals are almost necessarily easily destructible.

Any system which envisions the use of the standard padlock on the hasps of a freight car door suffers from the severe disadvantage or absolute impossibility of safely and efficiently transporting the padlock key so that it arrives at the unloading point at the same time as the freight car. Obviously the use of one key to open many padlocks is completely unsatisfactory since the loss or duplication of this master key at any point within the system would result in the loss of integrity of the entire system.

Any system of using combination locks would be subject to substantially the same kind of disability. For example, any code to determine the lock combination from the lock or box car serial number would be of value only for as long as it took a potential thief to break the code, or to obtain it from anyone in America who would have to be authorized to use it in order to open box cars whenever and wherever necessary.

The sophistication of externally applied padlocks is completely neutralized by the use of bolt cutters on the locking bars of the padlocks.

Equipping each box car with its own built-in locking device, whether having key operation or combination operation, is subject to the same difficulties and impossibilities; and additionally would require an expenditure of anywhere from $50 to $300 per box car to install.

Customarily, railroad cars are shunted around in railroad marshalling yards which extend over wide areas forming transfer points where trains coming from a variety of destinations are broken down into individual cars or strings of cars and made up agin into trains going to other destinations. It is in such marshalling yards and often in the dead of night when the great majority of the losses of goods from railroad cars takes place. Watchmen patrol these yards, and a certain amount of lights are used to make it possible to observe unauthorized persons in such yards; but often it is difficult or impossible to distinguish between persons moving along a widewalk or a roadway cutting across such a marshalling yard and persons intent on opening cars and stealing the contents, for example. If cars protected only by the frangible seal and a wedge shape locking bar are involved, the "casual passer-by" cannot be distinguished from the potential thief, inasmuch as the thief has to carry no special equipment, or, at the most, something which easily fits into his pocket to use as a hammer, a screwdriver of a pair of pliers or light wire cutters. To overcome the difficulties in adequately protecting railroad box cars, the method and device of the present invention were developed.

BRIEF SUMMARY OF THE INVENTION

Because the most sophisticated padlock extended through hasps on railroad cars and on railroad car doors is no more protection against destruction with a bolt cutter, than is a bolt immovably mounted through the same hasps; the present invention utilizes such a bolt. It is installed at the location where the railroad car is loaded and sealed, and is destroyed using a four foot long bolt cutter at the location where the railroad car is unloaded.

The locking bolt and a mating locking nut of the present invention are each case hardened to make them as impervious as is practical. A Rockwell hardness reading of 32 to 38 C has been found to be effective. The head of the bolt and the nut are rounded to make it as difficult as possible to prevent rotation of either after the bolt and the nut have been put together to form the locking device of the invention.

The shank of a bolt of the present invention is externally threaded at an outer end thereof opposite the bolt head. The nut is internally threaded to be easily screwed onto the bolt. The bolt threads terminate at an intermediate shank section of reduced diameter which extends for a distance at least as long as the threaded portion of the nut. The remainder of the bolt shank between the intermediate section and the head is of a diameter too large to receive any portion of the threaded nut.

In use, at least two hasps which are to be locked into position with respect to each other are aligned in the locked position, and the bolt of the invention is passed therethrough. The nut is threaded onto the bolt to position where it surrounds the intermediate shank section of reduced diameter and freely turns with respect thereto. At least a portion of the threads are then deformed so that the nut cannot be threaded back onto the threaded portion of the shank, and, consequently, cannot be removed from the shank.

The lock is now a permanent one, and cannot be removed without destroying the shank of the bolt at some point.

When it is desired that the lock be removed, an effective means of destroying the shank of the bolt is to employ a bolt cutter. Using a No. 8 bolt of the hardness suggested above, an effective bolt cutter will have arms of about 4 ft. in length. The minimum arm length of a bolt cutter to be heavy enough to do this job will be 3 ft.

By preventing access to the vicinity of such a lock by unauthorized persons carrying bolt cutters or other cumbersome equipment which cannot be easily concealed on the person, unauthorized destruction of the locks of the invention is effectively prevented.

In the drawings:

FIG. 1 is a fragmentary elevational view of the side of a railroad box car showing the car door slidably mounted thereon, and showing the locking device of the invention in place in hasps permanently mounted with respect to the car and the door;

FIG. 2 is an enlarged fragmentary view of the box car and door and disclosing the hasps and the device of the invention as seen in FIG. 1;

FIG. 3 is a further enlarge fragmentary perspective view of the structure of FIG. 2;

FIG. 4 is an enlarged vertical sectional view taken on the line 4--4 in FIG. 3;

FIG. 5 is an elevational view and a bottom end view of the locking device of the invention after the nut has been installed on the bolt thereof; and

FIG. 6 is an elevational view and a bottom end view of the device of the invention after the threads and outer shank section have been deformed to prevent the nut from being removed from the bolt.

DESCRIPTION OF PREFERRED EMBODIMENTS

A railroad box car 10 includes a side wall 12 on which a sliding door 14 is mounted.

There are many forms of door fastening arrangements to prevent opening of the railroad car doors with respect to railroad car openings in the walls of box cars, but one such structure to show the relationship of at least one hasp on a sliding door with respect to at least one hasp-like fastening fixed to the box car side wall will suffice to illustrate the use of the device and method of the invention.

In the structure as shown, an upper door hasp 16 is permanently fixedly mounted with respect to the door 14 and is provided with a lock or bolt opening 18 therethrough. A door frame hasp link 20 is provided with a loop 22 which is permanently secured on a side wall fastener hook 24 which is permanently mounted on the side wall 12 of the box car 10. Hasp link 20 is provided with a lock or bolt opening 26 therethrough, the hasp link 20 being movable to position to bring the opening 26 in vertical alignment with the opening 18 in upper door hasp 16, as perhaps best seen in FIGS. 3 and 4.

In this particular form of door fastening, which, in and of itself forms no part of the invention, a door wedge 28 is provided to fit through additional openings in upper hasp 16, in hasp link 20, and in a lower door hasp 30. Openings are provided at lower portions of the wedge 28 and the lower hasp 30 through which an elongated frangible seal 32 can be inserted in accordance with the present practice. To aid in the removal of the wedge, a wedge release arm 34 is pivotally mounted with respect to the lower door hasp 30 on the sliding door 12. This arm aids in releasing the wedge when it is to be removed, but forms no part of the present invention. It is sufficient to note that as long as the door wedge 28 is in place, the seal 32 will remain unbroken, and as long as the wedge is in place, hasp link 20 is maintained in fixed relationship to upper door hasp 16, and the door cannot be opened.

In this regard, it is to be observed that a locking device of the present invention could be utilized by passing a bolt of such locking device through the openings provided in the lower end of lower door hasp 30 and door wedge 28.

In the example of the invention as shown, however, the locking device of the invention, indicated generally at 36, includes a bolt 38 having a shank and a round head 40, and a threaded nut 42 also being substantially cylindrical around the outside thereof.

As shown, bolt 38 includes an outer, externally threaded, shank section 44, an intermediate shank section of reduced diameter 46, and an inner shank section 48 of normal nominal diameter such that no part of nut 42 can fit on it.

Nut 42 is internally threaded to receive the threads of the outer shank section 44 of the bolt 38. These external and internal threads can be of any usual, standard, or coarse configuration, but use of "non-standard" finer threads will make the deformation of threads easier, and will make it more difficult for destruction and replacement of one of the locks of the invention to go undetected, since bolts and nuts having such "non-standard" threads would not be as readily available and appearance of bolts and nuts with different threads would indicate that the original lock had been replaced. In fact, each shipper and each railroad can use a different design and size of thread, thus making it evident to persons at the point of the unloading of the box cars as to whether the locking device originally placed has been destroyed and replaced.

As shown, the longitudinal length of the outer threaded shank section 44 is shown to be somewhat longer than the longitudinal internal threaded dimension of the nut, but it is to be understood that normally a section of thread of approximately the length of the nut will suffice to give all of the strength needed. In fact, even a lesser length to the lower threaded shank section 44 will prove effective.

The intermediate shank section is shown to have a length slightly longer than the width of the threaded part of the nut. It is essential that this intermediate section provide clearance so that the nut can turn freely with respect to the bolt after it has passed off of the extrenal threads. In the usual case, it is not advisable to extend the length of this intermediate section to the point where it can be reached by a bolt cutter; but in some instances the shank length may be extended for just that purpose. In other cases, the intermediate section can extend clear to the bolt head and the inner shank section omitted.

In use, bolt 38 will be inserted through bolt opening 18 in upper door hasp 16 and through bolt opening 26 in door frame hasp link 20, and nut 42 will be threaded over outer externally threaded shank section 44 of the bolt to have position in alignment with intermediate shank section of reduced diameter 46. When the parts are in this position, they appear as seen in FIG. 5 and are positioned as seen in FIGS. 1, 2, 3 and 4.

Next, the threads will be deformed or destroyed so that the nut cannot be removed from the bolt. This deformation of the threads can be accomplished in several ways. As seen in FIG. 6, a large instrument, for example a bolt cutter with a flat jaw attachment, can be used to deform the lower shank section 44 by flattening opposite sides and pushing out opposite ends thereof.

Other means of deforming the threads include inserting a blunt instrument inside of the nut and between the threads of the nut and the intermediate shank section 46, and striking this instrument with a hammer. This sufficiently deforms the interior threads on the nut 42 to prevent it from ever being threaded back onto the lower threaded shank section 44.

When the box car has reached its destination and is to be unloaded, the lock is removed by positioning a bolt cutter 50 as indicated in dotted lines on FIG. 4. The arms of the bolt cutter are moved toward each other to cause the destruction of the bolt 38 of the locking device by cutting through upper shank section 48. The severed lower part of the bolt, together with the nut, will fall away, and the upper part remaining will be lifted out of the hasp 16. In the form of the invention as shown, door wedge 28 can then be removed in the usual fashion, and door 14 opened.

Other means of gaining authorized or unauthorized access to the contents of railroad box car 10 include use of a powered grinder on the bolt or on the nut; use of an acetylene cutting torch on the bolt, on the nut, on the bolt head, and/or on the hasps themselves; use of an explosive charge on the hasps, lock and/or door; and use of a steel cable or chain or the like around some portion of the hasps or bolt, with the application of gross force to the chain or cable to physically destroy the lock or hasps or door. Other means of gaining unauthorized access may suggest themselves; but all of the means as set out above, including the authorized means of the use of the bolt cutters, require equipment which is too bulky for a potential thief to carry on or about his person. Most of these methods of gaining unauthorized access also suffer from the very great disadvantage (from the view point of the thief) that they instantly reveal upon inspection that the security of the box car door has been violated, thus putting the law enforcement authorities on notice as to specifically where and when a break-in has occured. This will in many cases be a sufficient deterrent to the opportunist thief to prevent his attempt to open box car doors.

At the time and place where authorized destruction of the locking device is to occur, the use of a bolt cutter of sufficient size to easily destroy the bolt of the locking device is no more troublesome and is certainly less time consuming than the process of obtaining, from whatever source, a key keyed to the padlock installed at the point of departure, inserting that key into the lock and unlocking and removing the lock. This is also much cheaper than buying a lock for, or installing a permanent locking device on, every freight car in America; and is much more usable than a system involving the exchange of keys back and forth. Once every freight originating point is equipped with a hammer and a blunt chisel or the like to deform threads at the point of loading and every point of unloading is equipped with bolt cutters, the cost per transaction will be the cost of a bolt, or somewhere between $0.15 and $0.30 in all probability. If the threads which are destroyed are not the internal threads of the nut, the nut can be reused.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of using a non-reusable locking device including a bolt having a head, a threaded outer shank of maximum diameter and an intermediate shank section of lesser diameter and including a nut internally threaded of size and configuration to threadably receive said outer shank section and to turn freely on said intermediate shank section, said method including the steps of:

A. installing the shank of the bolt of the device in a position to serve as a locking bolt;

B. threading the nut over the outer shank section and onto the intermediate section;

C. deforming the threads of at least one of said nut and said outer shank section so that the nut cannot possibly be rethreaded on the outer shank section, thus to constitute the device as a permanent lock; and

D. destroying the device to release the lock by cutting through the bolt shank.

2. In combination with a hasp provided with a lock receiving opening therethrough, a non-reusable device for use as a lock to pass through said provided opening in said hasp, said device including:

a. a bolt having a shank of diameter to fit through a lock receiving opening in a hasp, a head at one end of said shank of dimension too large to fit through said opening, an end portion of said bolt shank opposite said head being externally threaded;

b. an internally threaded nut having an internal shape and size to threadably receive said threaded portion of said bolt shank and having an external size and shape too large to fit through said lock receiving opening in said hasp;

c. said bolt shank also including:

1. an inner shank section adjacent the bolt head, said inner section having a diameter greater than that of the internal diameter of the threaded nut, and

2. an intermediate shank section between the inner shank section and the threaded portion of said shank, said intermediate section having a diameter less than that of the innermost diameter of the internally threaded portion of the nut, said intermediate shank section extending between said inner shank section and said threaded portion for a longitudinal distance no less than the similarly measured longitudinal dimension of the internally threaded portion of the nut.

3. The non-reusable device of claim 2 wherein the threads of at least one of said externally threaded shank portion of said bolt and said internally threaded portion of said nut is made of deformable material.

4. The non-reusable device of claim 3 where said nut and said bolt head are round in outer peripheral form.