How do unions protect the rights of workers?

Answer 1

You do not give us any idea of which country you are in, and therefore the answer would be different.

In Australia --- It is better for the unions to 'collectively bargain" for higher wages, better penalty rates, better working condition including safety conditions. Collectively they can gain more than an individual can by himself. The unions can afford to take an employer to court to get their wishes, an individual can not afford to do so. Unions have people in their offices that know the law and what are the rights of a worker whilst many individuals do not. They can afford to use solicitors where as an individual would find it too expensive.
The unions are closely allied to the Australian Labor Party, and can ask the party, when they are in power, to change laws to assist with better welfare of workers.

Strikes and similar actions are always a last resort in many cases.

In Britain -- very similar to Australia.

In the US --- Here the situation is very different. Many of the unions are controlled by the Mafia and other criminal organisations and are also allied to the Republican Party. Therefore the unions are very weak and do little to assist the workers gain better conditions at work, but assist the employers against the workers in many cases. A FEW are decent unions and try to assist workers, but these unions are often persecuted by governments at both State and Federal levels.

Answer 2

They do this by what's called collective bargaining. They use the Law of Numbers...in other words, they negotiate for better working conditions or benefits packages based on the number of people they represent. This is quite often better than an idividual trying to do this on their own, since the more people that the union represents, the more pressure they can exert on the employer.

Answer 3

Strikes, power in numbers, etc.