Bolt seals for securing hasps on trailer truck doors and/or rail car doors which utilizes a round or oval head bolt which extends through the hasps and upon which a nut is threaded. The nut is threaded onto the bolt until it is tight and then a hollow tube is used to bend the bolt sharply to about 90° just under the nut.

Identification number areas are formed at the tail of the bolt and on a flat portion of the bolt adjacent the head. If a thief tries to break the seal by bending the bolt back to its original straight condition, the metallurgy of the bolt is selected so that the bolt breaks off. This indicates that the seal has been tampered with and furthermore, the thief finds that if he tries to turn the nut the round head of the bolt will rotate and since the threads are upset by the bending he will be unable to remove the nut. A modification of the invention utilizes a spin nut which is cylindrical in shape.

The present invention relates to a bolt seals comprising a round headed bolt receivable through the hasps of trailer truck or rail car doors and upon which a nut is threaded to secure the bolt. The bolt is bent to approximately 90° adjacent the nut by a bending tool. An identification number area is formed on the end of the bolt as well as on a flat portion adjacent the head of the bolt such that if a thief tampers with the bolt and attempts to straighten it the bolt will break,thus, indicating at the cargo receiving point that the seal has been tampered with. In one embodiment a nut is used on the bolt and in a second embodiment a spin nut is used which has an outer cylindrical shell and an inner threaded cylindrical portionwhich can be threaded onto the bolt until its tightened but which cannot be easily removed by turning the outer cylindrical shell since the outer cylindrical shell can rotate relative to the threaded portion.