Screwed jointing device
United States Patent [191 1111 3,876,316 Sandovist Apr. 8, 1975 [54] SCREWED JOINTING DEVICE 3.05194] 9/!962 Aholins et al 403/43 X [76] Inventor: Sune Allan sandovist 3 l63,()79 l2/l964 Schertz 403/43 X Vaktmastaregangen l l B 2. 413 13 G b s d Primary Examiner-Werner H. Schroeder [22] Filed: Jan. 18, 1973 1211 Appl. No.: 324,620 [571 ABSTRACT A screwed jointing device for interconnecting and se- [30] Foreign Appncation priority Data curing structural elements such as rods, bars and tubes Jan 19 Sweden 569, by means of simple tools to form stable structures and b comprising threaded elements of simple forms to facil- [52] U 5 cl 403/44 403/46 403/264 itate mass production in standard sizes. The jointing 403/343 device serves to interconnect elements of supporting I5 I] h&#34;. 7/18 structures or entire components of such structures to [58&#39; Fidd 46 258 form complete stable supporting structures with the 265 6 use of simple tools and without welding to thereby allow mounting and dismounting of inexpensive sup- 156] Reerences Cited porting structures or simple constructions and to move UNITED STATES PATENTS said constructions from one place of use to anotherv 2.497.384 2/1950 Young 403/343 X 4 Claims, 12 Drawing Figures SCREWED .IOINTING DEVICE This invention relates to screwed jointing devices for interconnecting and securing structural elements such as rods, bars and tubes by means ofsimple tools to form stable structures and comprising threaded elements of simple forms to facilitate mass production in standard sizes, said elements comprising an intermediate memher having internal and external threads of opposite hands to cooperate with internal threads of an external female part of a first structural element and with external threads ofan internal male member having one portion with threads of one hand for cooperation with the internal threads of said intermediate member and another portion with threads of opposite hand to cooperate with a threaded hole of a second structural element, and a spacer in the form of a sleeve which is slidingly but non-rotatably mounted on said threaded male member and by which the latter is rotatable to tighten the connection of said structural elements via said intermediate member.  
  Screwed jointing devices are used for interconnecting structural elements, such as bars and beams in supporting structures, or entire supporting structure components, such as trusses and frameworks, for instance planar or spatial frameworks, which shall permit ready erection and disassembly.  
  The term supporting structure herein is used as a general designation for all supporting structures in which use can be made of the screwed jointing device according to the invention, such as trusses, planar and spatial frameworks, framework panels, arches, cupolas, bridges, joistings. walls banisters, railings and scaffolds. However, the screwed jointing device according to the invention is not restricted to this very use but can be employed in many other cases for realizing quick coupling, for instance of connecting elements to form storage racks, pallet racks, desks, tables, cupboards and cabinets etc.  
  By way of example of prior-art devices for the fixation of for instance rods, bars or other elements in junctions, reference is made to French Pat. No. 73,569 which is an addition to French Pat. No. l,l8l,458, and to British Pat. Nos. 59I,570 and 886,968. The fastening devices according to these patents, however, suffer from certain drawbacks, int.al. the drawback of being useful only for successive interconnection of rods or the like or for realizing intersections or junctions one of which is fixed while the other is movable.  
  The present invention has for its object to eliminate these drawbacks and to provide a simple screwed jointing device of, e.g. metal, that can be readily mass produced in standard sizes by series production and which permits interconnection of elements of supporting structures or entire components of such structures to form complete stable supporting structures with the use of simple tools and without welding to thereby allow mounting and dismounting of inexpensive supporting structures or simple constructions and to move said constructions from one place of use to another.  
  The screwed jointing device according to the invention comprises an intermediate member which is arranged to be screwed into the external female part of the first structural member and which to this end has external threads for engagement with the threads of said female part and internal threads of opposite hand to that of the external threads for engagement with one correspondingly threaded end portion of a male member which has another end portion with external threads of the same hand as that of a threaded hole in the second structural element and is adapted, for the purpose of interconnecting the first and the second structural elements, to be screwed into the lastmentioned hole, and a spacer non-rotatably but axially movably mounted on the threaded male member and by which the latter is rotatable for interconnecting and clamping said first and second parts via said intermediate parts.  
  The invention is more fully described hereinbelow with reference to the accompanying drawings in which:  
  FIG. I shows a framework or framework section which at its ends is connected to the elements of a supporting structure at junctions realized with the aid of screwed jointing devices according to the invention;  
  FIG. 2 on a larger scale and in axial section shows a screwed jointing device according to the invention and its relation to the elements which shall be connected at the junction IV in FIG. I; said elements being shown in fragmentary vertical section;  
  FIGS. 3 and 4 are views similar to FIG. 2 but illustrate an intermediate stage of the connecting operation and the final stage thereof, respectively, when the elements are interconnected by means of the screwed jointing device in FIG. 2 at the junction IV;  
  FIGS. 50 5d are axial views of the details of the screwed jointing device shown in FIGS. 2-4;  
  FIGS. 6d are cross-sections of the details shown in FIGS. 5a 5d.  
  The framework 1 illustrated in FIG. 1 is connected at its ends to structural elements 2, 3, with which the framework 1 shall be incorporated, by means of screwed jointing devices of the type illustrated in FIGS. 2-6.  
  Each screwed jointing device comprises an external female part 4 which may be a tubular rod of the framework l, which is to be connected by means of the screwed jointing device according to the invention, or a tubular part fixedly connected to the framework. The female part 4 at its end portion has internal right-hand threads for engagement with an intermediate member 5 having external right-hand threads and also internal left-hand threads meshing with the threaded end portion 6&#39; of an inner male member generally designated 6. The threads of said one end portion 6 of the male member 6 are left-handed, while the other end portion 6&#34; of the male member has right-hand threads. Outwardly of the tubular female part 4 the male member 6 on its end portion 6&#34; having the right-hand threads carries a spacer in the form ofa sleeve or ring 7 which is freely axially movable on the male member 6 but is non-rotatable in relation to said member 6 in that an axial rib or key 8 at the inner side of the spacer ring 7 engages in a conforming axial keyway 9 in the male member 6. The male member 6 can be rotated by rotation of the spacer ring 7 with the aid of a tool, e.g. a pipe wrench. Instead of the illustrated device for rotational connection of the spacer ring 7 with the male member 6, of course, any equivalent device may be used.  
  It will be realized from the foregoing that the screwed jointing device has an effect similar to that of a turnbuckle, but in which use is made of a male member whereof the end portion 6&#39; having the left-hand threads is adapted to be screwed into the intermediate member having internal left-hand threads, while the end portion 6&#34; of the male member having the righthand threads is adapted to be screwed into a hole of internal right-hand threads formed in the structural element to which the external female part 4 is to be connected.  
  A hole permits the insertion ofa stop means which serves to adjust the axial position of the intermediate member 5 on the male member 6. A stop screw for the intermediate member 5 is designated 11.  
  As will clearly appear from FIG. 5d the male member 6 has an abutment 12 which separates the keyway 9 in the male member 6 from the end thereof. Moreover, a non-threaded intermediate section of the male member 6 between the threaded portions. 6&#39;. 6&#34; of the male member 6 is designated 13.  
  According to the invention. the screwed jointing device functions in the following way. From the initial po sition in FIG. 2 the male member 6 is screwed to the :right by rotation of the spacer ring 7 with the aid of a tool. When the intermediate member 5 has reached the stop screw 11 the parts occupy the position shown in FIG. 3, in which there is a small clearance 14 between the element 2 and the spacer ring 7. When the spacer ring 7 is further rotated from this position, the male member 6 is screwed into the element 2 and simultaneously draws the intermediate member 5 and the fe male part 4 towards the element 2 so that the clearance 14 disappears. A firm tightening of the spacer ring 7 will thus fixedly clamp said spacer ring between the femaie part 4 and the element 2. The left-hand threads of the male member 6 and the left-hand threads of the intermediate member 5 in fact require a much greater torque to bring about a movement than the right-hand threads within the female part 4 and on the outside of the intermediate member 5.  
  In the position illustrated in FIG. 4 all clearance has disappeared because the end portion 6&#39; of the male member 6 having the left-hand threads has been screwed into the intermediate member 5 when the movement of said intermediate member is stopped by means of the screw I].  
 What I claim and desire to secure by Letters Patent l. A screwed jointing device for interconnecting and securing first and second structural elements such as rods, bars and tubes by means of simple tools to form stable structures and comprising threaded members of simple form to facilitate mass production in standard sizes, said members comprising an internally threaded female portion of said first structural element. an inter nal male member having a first portion with external threads ofone hand and a second portion with external threads of opposite hand. an internal member having internal and external threads of opposite hands and adapted to be screwed into said female portion of said first structural element and onto said first portion of said internal male member by relative rotational movement of said element and said members, said second structural element having an opening adapted to receive said second portion of said internal male member and threaded for screwing engagement with the threads of opposite hand of said second portion of said internal male member, and a hollow rotatable spacer and tightening means which is axially movably mounted on, but which in respect to rotational movement is connected with. said internal male member in a position between said second structural element on the one hand and said intermediate female member and said first structural element on the other hand, said internal male member being rotatable by rotation of said spacer and tightening means to tighten the connection of said first and second structural elements via said internal male and intermediate female members.  
  2. A screwed jointing device as claimed in claim 1, further comprising stop means on said external female portion ofsaid first structural element. said stop means serving as an end position stop for said intermediate female member in relation to said external female portion of said element.  
  3. A screwed jointing device as claimed in claim 1, wherein said external female portion of said first structural element is formed with an opening to permit presetting of the position of said intermediate female member on said internal male member.  
  4. A screwed jointing device as claimed in claim 1, wherein the parts consisting ofsaid spacer and tightening means and said internal male member have means in the form of an axial key on one of said parts and an axial keyway in the other part and adapted to determine the relative angular position of and to permit axial displacement between said parts.