If you look at a product that is similar to the one you want to produce, and it reads 'patent pending' on it, then you are screwed!  Not really, but it is difficult because pending patents are not published.  There is no way for you to be sure which element on the product is original and which ones are prior art (see my post on patents for a further explanation of prior art).  You are not even sure which elements they are even claiming in the patent because there is no way to read the patent application while it is under review.  Actually, you can get a copy of it to read, but it is very difficult.  You have to send in a separate specific request to the US Patent and Trademark Office and pay a fee (as opposed to downloading free published patents from the USPTO website).  To do that you would have to know specifically which pending application to ask for.  Since there is no number or any other published information (inventor, company, etc.) yet associated with a pending patent application, it is very difficult to try to find which application to even ask the USPTO for.

So, if the product that is similar to your new product is patent pending, then you are in for an uphill battle until that patent is published.  The best you could do is find examples of prior art contained in your competitor's product, and if your product contains those same elements as the prior art, then you are probably safe.  Any elements not clearly in the prior art should not be included in your product until you know the details of the claims when your competitors patent gets published. 

If it is your own product that you have applied for a patent on and it is patent pending...that is probably the best possible thing you could list on your product.  You would leave all would-be copiers flummoxed as they tried to figure out which elements of your product are original.  Furthermore, if you have a patent pending, you might not get the patent granted, but as long as it is pending nobody will dare to copy it exactly until they know if it is granted or not.  What would be ideal is if you could have 'patent pending' on your products forever.  No doubt some people probably just put that on their products whether it is true or not.  But if the USPTO catches you..or if your competitors catch you then you could be liable for big fines, penalties, and lawsuits. 

When I was deciding on a design for a locking mailbox I ran into a 'patent pending' problem.  In a previous post on the topic I pointed out that it seemed like making a tray type design (as opposed to a narrow slot design) for the locking mailbox would be the most effective design because then it could take packages as well as letters.  However, during my research, I found an existing tray type design already on the market.  I duly purchased one to check it out.  In my investigations I noticed that it had 'patent pending' on the manufacturers label.  Now, at this time, I knew nothing about patents or intellectual property law.

So, I looked up a guy in the yellow pages who did patents (not a lawyer) and went to talk to him.  I told him that the design I wanted to make was similar to the design of the mailbox I had purchased, but I was concerned about the patent pending on this one.  The patent guy told me there was no way to know what the designer of this mailbox was trying to patent since it was 'patent pending' and none of the information was yet published.  Overall, this guy was not very helpful and he basically told me that he would not try to make a locking mailbox of a tray design because of the patent pending status of this mailbox.

Well I could not accept that answer.  I mean come on, there are thousand of examples of tray designs in depository boxes.  All the UPS, DHL, and FedEx boxes are a tray design.  All the libraries have book depositories that are tray designs as well as banks, and not to mention the blue R2D2 boxes that the US Post office runs.  You can't tell me that the guy who makes this tray design has an exclusive patent on all tray type mailboxes or depository boxes.

But his point was, that may be so, but if you make a mailbox similar to this one, since you don't know what claims the designer of this mailbox has on his pending application, you don't know if your design will violate his patent, if he is even granted a patent.

So....... I thought...either give up...or do more research.  Well, I don't like to be told that I can't do something.  So, I decided that this 'expert' was not much help and it was time to do more research.