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Title: Fluid pressure operated actuator with safe disassembly means
Claims: What is claimed is: 1. A fluid pressure operated actuator comprising: a cylindrical housing having at least one open end; a disengageable end closure fastened to said open end of said cylinder; a piston rod extending into said cylindrical housing for axial movement relative thereto between a contracted position and an extended position; spring means within said cylindrical housing for urging said piston rod towards a predetermined one of said positions; wherein said spring means includes at least one compression spring disposed coaxially around a portion of said piston rod within said cylindrical housing; means for admitting pressurized fluid into said cylindrical housing for forcing said piston rod towards the other of said positions against the force of said spring means; a first annular spring retainer disposed coaxially within said open end of said cylindrical housing and having said spring abutted thereagainst, and a second annular spring retainer disposed coaxially within said cylindrical housing and being abutted against the other end of said spring and being slidable within said housing with said piston rod; and stop means for limiting relaxation of said spring means as said end closure is being disengaged from said cylindrical housing, wherein said stop means includes an element carried on said piston rod in position to be abutted by said first spring retainer as said first spring retainer is urged out said open end of said housing by said spring as said end closure is in the process of being removed from said housing, said stop means being a cross pin extending transversely through said piston rod and having ends extending radially therefrom to block movement of said first spring retainer along said piston rod after said end closure has been partially disengaged from said cylinder. 2. A fluid pressure operated actuator comprising: a hollow cylinder having an open rod end and a closed head end and having a fluid port in proximity to said head end, an annular first spring retainer disposed coaxially within said rod end of said cylinder, a piston rod extending axially into said cylinder through said first spring retainer, a second annular spring retainer disposed within said cylinder in coaxial relationship to said piston rod and being slidable within said cylinder with said piston rod, a helical compression spring, disposed in said cylinder in coaxial relationship with said piston rod and being compressed between said first and second spring retainers to exert a force urging said piston rod towards said head end of said cylinder, a removable annular end cap encircling said piston rod at said open end of said cylinder and being threadably engaged upon said open end of said cylinder and being removable therefrom by rotation accompanied by axial movement relative to said cylinder, said end cap having means abutting said first spring retainer for holding said first spring retainer within said open end of said cylinder while said end cap is engaged thereon and for causing said first spring retainer to exert compressive force on said spring as said end cap is threaded onto said cylinder, and means forming a radially extending surface on said piston rod which is positioned to be abutted by said first spring retainer only after said end cap has been partially unthreaded from said cylinder to stop expansion of said spring prior to complete disengagement of said end cap from said cylinder. Other info: Inventors: McLuckie, Walter L. (Coal City, IL, US) Application Number: 477759 Filing Date: 1974-06-10 Publication_date: 1976-05-11 Assignee: Caterpillar Tractor Co. (Peoria, IL) Primary Class(es): 92/128 92/130R, 92/168, 92/171.1, 92/255 Other Classes: US Patent Ref:
Other Refs: Primary Examiner: Maslousky, Paul E. Assistant Examiner: Attorney: Phillips, Moore, Weissenberger Lempio & Strabala |
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