When Carlsbad resident Dwight Johnson’s arthritis made it difficult to attach leashes to his dogs’ collars, he did what came naturally — for him. He invented a clip that takes just the push of a button to attach a leash securely to the D ring on a collar.

That was nothing new for Johnson, 70. Since his first invention in 1972, he has held about 80 patents, mostly for plumbing hardware. The first was a toilet tank fill valve that worked so well he sold it to Delta Faucet in 1981 and was then retained by Delta as a consultant for three years.

“That was when I went into business for myself,” he says. Before that he had worked as a research manager that catered to the natural gas industry. He opened Johnson Design in Carlsbad to produce what he created. Although he is not inventing as actively as he did, he says there is always something of his at a Home Depot or Ace hardware store.

His move into animal products, he says, has to do with an old adage: Necessity is the mother of invention. Hence the leash clip, which makes his morning walk with his two poodles much easier. Designed for dogs up to 30 pounds, the Leash Clip is manufactured in Carlsbad and is available at several North County pet stores; by telephone at (877) 695-3274 or online at LeashClip.com. A four-foot leash is $6.95. The six-foot leash is $9.95.

— Sandy Pasqua