DALLAS (AP) A North Texas man has been sentenced to more than four years in federal prison in a nearly $1 million investment scam involving trailer hitches.

Prosecutors in Dallas on Tuesday announced the sentence for Karl G. Pratt of Granbury. Pratt pleaded guilty to wire fraud.

Pratt was arrested last January over a scam since 2009 that drew about 50 investors to his company, Safety Sentry Inc.

Investigators say Pratt falsely claimed to have patented a device to prevent a trailer hitch from coming loose during towing. Another claim was for a device that would deter theft of a parked and unattended trailer.

Pratt, who on Monday was also ordered to make $979,000 in restitution, didn't tell investors that his patent applications were denied.