Control device, parts therefor and methods of making the same

In a method of making a temperature sensing unit comprising a housing means for being secured to desired structure, a tubular member having an open end secured to said housing means and having another end disposed remote from said housing means, a rod means disposed in said tubular member and having a first end projecting out of said open end of said tubular member, said rod means having a second end disposed adjacent said other end of said tubular member, said tubular member having abutment means disposed between said ends thereof, and a heat expandable and contractible polymeric member disposed between said second end of said rod means and said abutment means to tend to cause said first end of said rod means to move away from said open end of said tubular member upon said unit sensing decreasing temperature and to tend to cause said first end of said rod means to move toward said open end of said tubular member upon said unit sensing increasing temperature, the improvement comprising the steps of operatively interconnecting biasing means to said unit to continuously place said tubular member under compression between said open end thereof and said abutment means thereof and to continuously place said rod means under tension between said ends thereof, operatively interconnecting said biasing means to said first end of said rod means, forming said biasing means to tend to move said rod means away from said open end of said tubular member, and forming said second end of said rod means to have shoulder means compacting said polymeric member against said abutment means of said tubular member to tend to compress said tubular member between said abutment means and said free end thereof toward said housing means.