The victims - an elderly man, aged in his 70s, and a woman in her 50s - were injured in the burglary in Justin Close. The man suffered a head injury.
The male suspect stole several items of jewellery, including two solid gold bracelets, a solid silver ring, and some cash.
Officers are on the hunt for the attacker described as a black man, around 6ft tall, and in his mid-20s to mid-30s. He is said to be of a slim build, clean shaven and was wearing a dark fleece zipped up with the hood over his head.
The burglary took place on Sunday (March 8) at around 2.20pm and the couple were attacked as the suspect fled the house.
Detective Sergeant Andy Thrower, of Hounslow Serious and Acquisitive Crime Unit, said: "The elderly and vulnerable male victim sustained a head injury after being confronted in his own home.
"He has since received hospital treatment and is now making a steady recovery.
"Both victims are still understandably shaken and frightened as the circumstances of this attack could have resulted in a dire outcome.
"We are investigating the events which led to the suspect entering the victims' home.
"We are particularly keen to speak to anyone who may have witnessed suspicious behaviour, in the vicinity of Brentford Docks between 1.45pm to 2.45pm that day."
Anyone with information should call Hounslow Serious Acquisitive Crime Unit on 020 8247 6094 or Crimstoppers anonymously on 0800 555 111.