Spring base for upholstered seating
llnited States Patent 1191 Platt et al.  
 [451 Apr. 29, 1975 SPRING BASE FOR UPHOLSTERED SEATING [75] Inventors: John G. Platt, Carthage; Robert 0.  
 Isaacs, Joplin, both of Mo.  
 [73] Assignee: Flex-O-Lators, llnc., Carthage, Mo.  
 [22] Filed: May 3, 1974 [21] Appl. No.: 466,726  
 3,117,774 1/1964 lsaacs 267/80 3,147,968 7 9/1964 Gunlock et al. 267/107 X 3,559,977 2/1971 lsaacs 267/90 Primary Examiner-James C. Mitchell Attorney, Agent, or Firm-John A. Hamilton 1 1 ABSTRACT A spring base for upholstered seating consisting of a series of spring units extending across a seating frame in generally parallel relation, each spring unit consisting of two identical spring members each consisting of a length of heavy spring wire having an angled terminal portion and an arm portion with a transversely opening hook at its free end, the terminal portions of the two members being fixable to opposite frame rails [56] References Cited with the arm portions thereof extending in overlapping UNITED STATES PATENTS relation across the frame, the overlapping arm por- 728,496 5/1903 Parker 1. 5/255 tions b i twisted together i h hook of each arm 2,002,158 5/1935 Rccd i a 5/267 X engaged about the other arm 2,592,944 4/1952 5/260 X 2,657,738 11/1953 Kruszona 267/107 5 Claims, 17 Drawing lFigures l f 9-- 20 22 24 AZ 25 14 2; 20  
  f ,1 24 f 7 J A;  
  f 5% ,2; ZZ A? if 4 2 29 @d f J =F-= pgf AZ SPRING BASE FOR UIIIOLSTERED SEATING This invention relates to new and useful improvements in seating structures, and has particular reference to the spring base or support structure for upholstered seating.  
  The base or support spring structures for upholstered seating units of furniture or automotive seating may take many forms, most commonly employing vertical coil springs distributed over the area of the seat and affixed at their lower ends to rigid support members fitted into the seating frame, or a series of heavy sinuous wires extending across and affixed at their end to the seating frame, the latter being commonly known as zig-zag springs. However, all such spring structures within our knowledge have been subject to certain disadvantages. For example, their installation in a seating frame has been a tedious, time-consuming operation, and hence expensive from the point of view of labor required. Their installation has required special tools and jigs. Also, for the most part it has been necessary that they be pre-formed accurately to the size of the seating frame in which they are to be installed.  
  Accordingly, the principal object of the present invention is the provision of a spring base for upholstered seating which obviates all of the above enumerated difficulties and disadvantages of previous structures, in that it may be installed very rapidly and easily, the installation of which requires no special tools, nor in fact any tools at all, and which may, within reasonable limits, be adjusted to fit seating frames of different sizes. Generally, these objects are accomplished by the provision of a spring base adapted to be mounted in a seating frame and consisting of a series of elongated spring units extending in generally parallel relation across a seating frame, each unit consisting of a pair of identical spring members each comprising a length of heavy spring wire having at one end a downturned terminal portion adapted to be affixed to the frame, the terminal portions of the two members being affixed to opposite frame rails, and arm portions extending into overlapping relation across the frame, the overlapping portions being twisted together, and each arm having at its free end a transversely opening hook engaged about the other arm. The two members may be assembled and twisted together before attaching the terminal portions to the frame, and the twisting insures engagement of the hooks with the arms. Each hook may slide longitudinally along its associated spring arm to adjust the length of the unit.  
  Other objects are simplicity and economy of construction, and efficiency and dependability of operation.  
  With these object in view, as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:  
  FIG. 1 is a top plan view of a spring base for upholstered furniture embodying the present invention,  
  FIG. 2 is a sectional view taken on line IIII of FIG.  
  FIG. 3 is a side elevational view of one of the spring members utilized in the spring base, shown separately from the total structure,  
  FIG. 4 is a top plan view of the spring member shown in FIG. 3,  
  FIG. 5 is an enlarged sectional view taken on line V-V of FIG. 3,  
  FIG. 6 is an enlarged, fragmentary sectional view taken on line VI-VI of FIG. 1,  
  FIG. 7 is a top plan view of the structure shown in FIG. 6,  
  FIG. 8 is a sectional view taken on line VIIIVIII of FIG. 6,  
  FIG. 9 is a fragmentary sectional view taken on line IX-IX of FIG. 6,  
  FIG. 10 is an enlarged, fragmentary view similar to the left portion of FIG. 2, but showing a modified end connection for the spring units,  
  FIG. 11 is a view similar to FIG. 10, but showing a modification of the end connections suitable for use with steel seat frames,  
  FIG. 12 is a fragmentary plan view of the elements shown in FIG. 11,  
  FIG. 13 is a view similar to FIG. 12, but showing still another type of steel frame end connection,  
  FIG. 14 is a sectional view taken on line XIV-XIV of FIG. 13,  
  FIG. 15 is a top plan view similar to FIG. 13 but showing a torsion type end connection suitable for use with wooden seat frames,  
  FIG. 16 is a view similar to FIG. 15, but showing a modification of the torsion type end connection suitable for use with steel seat frames, and  
  FIG. 17 is an enlarged sectional view taken on line XVII-XVII of FIG. 16.  
  Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies generally to a seating frame consisting of four rails 4, 6, 8 and 10 rigidly joined together to form an open rectangular enclosure. For convenience rails 4 and 6 may be designated the front and rear rails respectively, and rails 8 and 10 as the side rails. Extending between a pair of opposite rails, front and rear rails 4 and 6 as shown although they could also extend between side rails 8 and 10, are a plurality of generally parallel spring units each designated generally by the numeral 12. Each spring unit consists of a pair of identical spring members each designated generally by the numeral 14. Each spring member 14 consists of a single length of heavy spring wire, No. 8 or No. 9 wire having proved satisfactory although this is a matter of proper design choice. Starting from its associated frame rail 4 or 6, in the form of the invention shown in FIGS. 1-10, each spring member 14 consists of a downturned terminal portion 16 adapted to be inserted downwardly into a hole 18 formed therefor in the upper edge of the rail sufficiently tightly to prevent rocking thereof transversely of its axis, an arm 20 extending generally at right angles to terminal portion 16, a circular coil 22 (of two full turns as shown) disposed generally in a vertical plane beneath the general extent of the wire, a load arm 24 extending toward the opposite frame rail but at an upward angle as compared to arm 20, and being of such length not to extend to the coil 22 of the associated spring member, and a transversely opening hook formation 26 at the free end of arm 24. Arms 24 of the associated spring members are flexed downwardly to lie in overlapping relation, and the overlapping portions are twisted together (one full turn as shown at 28), with the hook 26 of each engaged about the arm 24 of the other. The spring members 14 of each spring unit 12 may conveniently be assembled together into frame 2 by first taking two spring members 14, separately from the frame, relatively reversing them, and engaging the hook 26 of each about the arm 24 of the other, then twisting the arms 24 together, using terminal portions 16 as handles for this purpose, then inserting one of terminal portions in its associated hole 18, and finally, while flexing the spring unit transversely by manual force, inserting the other terminal portion 16 in its hole 18. This assembly may be accomplished manually without use of any tools. It will be noted that for the spring tension of arms 24 to hold hooks 26 in firm engagement with said arms, the hooks should open oppositely to the direction of twist desired. That is, if the wires are twisted in a right-hand direction, as shown, hook 26 should open to the left, looking toward the end of the arm as in FIG. 5, and vice versa.  
  To maintain the transverse spacing between spring units 12 during usage of the spring base, one or more transverse stabilizing strands 30 (one shown) are laid across the base at right angles to the spring units, and secured to each spring unit at its point of intersection therewith by a spring clip 32. As best shown in FIGS. 8 and 9, strand 30 may consist of a spring wire core 34 having a sheath 36 of soft, indentable material such as twisted paper or the like. Said sheath provides a good purchase for clips 32 thereon, and also acts as a quieting means in that it prevents rubbing or grating noises as a result of relative movement between wire 34 and spring arms 24. As shown in FIGS. 6-9, each spring clip 32 consists of a length of spring wire formed to present a downwardly opening hook 38 engageable over the top of strand 30 at one side of spring arms 24, the wire extending from both ends of said hook to form first a saddle 40 engaged under spring arms 24, and then an upward bight 42, said bights extending upwardly at opposite sides of strand 30 at the side of spring arms 24 opposite to hook 38. The wire is extended from one of bights 42 to form an arm 44 having at its free end a downwardly opening hook 46 engageable over strand 30. Arm 44 must be flexed upwardly to engage hook 46 over strand 30, and in so doing spring arms 24 are clamped firmly against strand 30 by hook 38, saddles 40 and bights 42 of the clip. These clips may also be applied manually with no requirement for tools. Clip arm 44 may be formed with a transverse bight 48 which serves as a finger tab in flexing said arm.  
  In operation, it will be understood that the usual upholstery layers, consisting usually of an insulator sheet, a thick layer of padding material, and a cover sheet, are applied over the spring base as shown, the insulator sheet preventing the padding material from working down between the spring units, and distributing the load more evenly to the spring units, and the cover sheet enclosing the padding material, being pulled downwardly around the edges of the base and secured to frame 2. These upholstery layers, particularly the cover sheet, prevent the terminal portions 16 of the spring members from working upwardly out of frame holes 18. If necessary, a staple (not shown) could be engaged over arm 20 of each spring member and driven into the frame.  
  It will be seen that the angularity between arms 20 and 24 of each spring member, when the member is relaxed as shown in FIG. 3, provides that when the base is assembled, the deck defined in skeleton form will be upwardly bowed, as shown in FIG. 2. This crowning of the base is usually desired, in that it permits crowning of the finished seating structure without requiring specially formed padding layers. If crowning were not desired, arms 20 and 24 of each spring member could be made normally parallel. The degree of crowning can be varied by changing the degree of normal angularity between arms 20 and 24, a more acute angle producing a more pronounced crowning, and a more obtuse angle producing a lesser degree of crowning, or by changing the gauge of the wire used, or the number of turns in coils 22.  
  The overlapping of spring arms 24 in the central portions of the spans of the spring units stiffens this portion of the span of the base against downward flexure, and this is considered desirable in preventing or lessening of any tendency of the base to sag or hammock in the mid-portion thereof. Such hammocking is not considered conductive to the greatest degree of user comfort by present day standards. Stated in another manner, the stiffening provided by overlapping of the spring arms causes the central portion of the base, which of course is the area thereof normally loaded, to yield downwardly more nearly as a platform supported yieldably at its edges, with a greatly reduced degree of hammocking sag. The twisting of the spring arms together further tends to stiffen the overlapping portions thereof, so long as the arms are not strained beyond their elastic limits. The general stiffness of the spring base can be changed by spacing the spring units closer together or farther apart, or by changing the weight of the wire used, or by changing the number of turns of wire in coils 22, or by eliminating said coils. Coils 22 have the added function of eliminating much of the stress at the angle between arm 20 and terminal portion 16 of each spring member. This is normally a point of high stress concentration, where breakage could occur.  
  Finally, it will be seen that since the hook 26 of each spring member is free to slide longitudinally along the arm 24 of its associated spring member, the distance between terminal portions 16 can be changed to adjust the spring unit to seating frames having different distances between rails 4 and 6. Extension or retraction of each spring unit in this manner of course changes the length of the overlapping portions of arms 24, and hence has the effect on the yield characteristics of the base of respectively weakening or strengthening it against downward yielding. However, adjustment over a considerable range is possible without materially adverse effects on the overall yield characteristics, and if still greater adjustment is desire, the weakening effect of greater extension can be offset by using more units spaced more closely together, and the stiffening effect of greater retraction can be offset by using fewer units spaced further apart. Thus it will be apparent that a spring base having a wide range of adaptability both as to variable sizing to fit frames of different sizes and contours, and as to variable yield characteristics, has been provided.  
  FIG. 10 shows a modification of the end mounting of the spring units 12 in which the downwardly turned terminal portion 16 of each arm 20, instead of being inserted in a drilled hole of the frame, is simply laid against the outer surface of the associated frame rail, and secured thereto by staples 48 driven into said rail. Another stable 50 may be driven into the top of the rail to secure arm 20. This connection is perhaps simpler than that previously described, requiring no special preparation of the frame rails, and can be used whenever the resulting projections from the outer surface of the rail are not considered to be objectionable. Also, it  
 permits the unit to be inserted between the rear rail of the seat frame and the bottom rail of the back frame of the seating structure while it is turned 90 on its axis to place terminal leg 16 horizontally, and then turned into proper position with leg 16 vertical before driving the staples. Often there is not sufficient vertical spacing between these seat and back rails to permit downward insertion of legs 16 into the holes 18.  
  FIGS. 11 and 12 show a modified end connection suitable for use with steel seating frames, the rails thereof being illustrated as constituting a steel angle iron having a vertical leg 52 and a horizontal&#39;top leg 54. In this case, the vertical terminal leg 16 of each spring member may be inserted downwardly through a hole 56 formed in top leg 54, and through an eye member 58 struck inwardly from vertical leg 52. Also, as shown in FIGS. 13 and 14, terminal spring leg 16 may overlie the outer surface of vertical angle iron leg 52, being inserted through an eye member 60 struck outwardly from said leg 52.  
  FIG. 15 shows a modification wherein each spring unit arm 20, instead of having a vertical terminal portion 16 as before, has a terminal portion bent first to form a horizontal leg 62 extending at right angles to arm 20, and a short leg 64 rebent to extend generally parallel to arm 20. Legs 62 and 64 may simply be laid on the top of a wooden frame rail, as in FIG. 15, and affixed thereto by staples 66. In the case of a steel frame rail, spring leg 62 may be laid between upward protuberances 68 struck from angle iron leg 54, and a flap 70 struck from leg 54, and the flap then bent downwardly to secure spring leg 62 in place, as indicated in FIGS. 16 and 17. FIG. 17 shows flap 70 in dotted lines in the position it occupies before it is bent to secure the spring. Spring legs 64 abut the rail to prevent free downward pivoting of spring legs 20, but legs 62 may nevertheless yield in torsion. Therefore, as legs 20 are flexed downwardly in the usage of the seat, spring legs 62 yield in torsion. This distributes the spring stress along a substantial length of the spring wire, rather than concentrating the stress at the angle between legs 20 and 62, and thus further serves to relieve stresses at that angle and further to reduce the likelihood of fatigue failure at that point. Also, this type of end connection permits horizontal insertion of the spring ends between the rear seat frame rail and the bottom back frame rail, as discussed in connection with the end connection shown in FIG. 10.  
  While we have shown and described certain specific embodiments of our invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention.  
  What we claim as new and desire to protect by Letters Patent is:  
  1. A spring base for upholstered seating comprising a series of generally parallel spring units each adapted to extend between and be anchored at its respective ends to opposite rails of a seating frame, each of said spring units comprising a pair of elongated spring members each having a terminal portion adapted to be affixed to one of said frame rails, an arm extended toward the other of said frame rails, but terminating short of said other frame rail and overlapping a portion of the arm of the other spring member, and a transversely opening hook at the free end of said arm, the overlapping portions of said spring member arms being twisted together along the entire lengths thereof, and the hook of each of said spring arms being engaged about the arm portion of the other of said spring members.  
  2. A spring base as recited in claim 1 wherein said hook of each of said spring member arms opens transversely of said arm in a direction opposite to the direction in which said arms are twisted together, whereby said hooks are secured in engagement with said arms by the resilience of said arms.  
  3. A spring base as recited in claim 1 wherein each of said spring member arms, when relaxed, follows a line passing above the opposite frame rail, whereby when said arms are secured together by said twisting and said hooks, they assume an upwardly bowed configuration.  
  4. A spring base as recited in claim 1 wherein said hooks are operable to permit relative longitudinal movement between the overlapping portions of said spring member arms when said arms are not twisted together, whereby the distance between the terminal portions of said members may be adjusted to frames having different distances between said opposite rails thereof, but wherein said relative longitudinal movement of said arms is prevented by the twisting of said arms together between said hooks.  
  5. A spring base as recited in claim 1 wherein each terminal portion of each of said spring units is formed to present successively a horizontal transverse leg extending generally at right angles to the general extent of said spring unit, and adapted to overlie a top surface of its associated frame rail, and a horizontal extreme end leg also overlying said frame rail top surface, and forming a generally U-shaped configuration in conjunction with said transverse leg and the adjacent portion of the associated spring arm, and with the addition of attaching means for securing said transverse leg to said frame rail; said attaching means being operable to permit torsional yielding of said transverse leg.