Patent Publication Number: US-11045002-B1

Title: Quick-release footrest device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/796,044, filed Jan. 23, 2019, which is hereby incorporated by reference. 
    
    
     FIELD 
     The present invention relates generally to office furniture, and more particularly to devices for disassembling office furniture quickly and easily. 
     BACKGROUND 
     In the exhibitor and conference industry, office furniture is repeatedly transported in trucks, unpacked, set up, used, and then packed back into the trucks for transportation to a warehouse or other storage facility. Some pieces of furniture—conference tables, media screens, speakers, etc.—are fairly easy to pack; they can be laid flat, rolled up, or packed into road cases and then placed into the truck. Items such as these may be densely packed because they are either small or large but heavy. 
     Some types of furniture, such as office chairs and table tops, present packing issues, however. Table tops generally have to be completely dismantled. Office chairs are relatively light but are quite large and cumbersome. They generally cannot be laid flat, rolled up, or packed into a box. Indeed, most office chairs cannot be disassembled: almost all office chairs have a seat back and a seat bottom mounted on a seat plate. The seat plate connects to a gas-lift or non-gas-lift cylinder that is then mounted in a wheelbase. Moreover, tall draft chairs have footrest rings or split rings mounted on the gas-lift cylinder. 
     At least one invention, disclosed in U.S. Pat. No. 10,260,671 entitled Gas Cylinder Quick Release Device, describes devices for separating the gas cylinder from the seat bottom and from the wheelbase. Gas cylinders typically have an external sleeve and a rod which reciprocates in the sleeve. The rod is usually directed upward while the sleeve is downward, such that the rod is press fit into the seat plate and the sleeve is press fit into the wheelbase. A fastened socket in the seat plate receives the rod, and a socket—generally a circular hole—in the wheelbase receives the sleeve. When the chair is assembled in this fashion and a user sits in the chair, the rod and sleeve further press into the seat plate and the wheelbase, setting the gas cylinder securely. Over just a few hours, the gas cylinder is driven into a firm and very secure press-fit engagement with the seat plate and the wheelbase. Over days, months, and years, the gas cylinder becomes nearly permanently seated into the seat plate and the wheelbase. When such chairs are transported and stored, the device disclosed in U.S. patent application Ser. No. 15/715,334 allows the chair to be broken apart for better shipping, despite the very tight press-fit engagement between the gas cylinder and the wheelbase. 
     On some drafting or office chairs, the footrest rings are generally applied to the gas cylinder before the seat plate and the wheelbase are mounted to the gas cylinder and are then secured with a set screw about an inner compression sleeve. As such, they cannot be removed at all. These create a bulky obstacle to the compact packing and shipping of such draft chairs. A way to decouple or remove the footrest ring is needed. 
     SUMMARY 
     A footrest device supports feet apart from a cylinder and includes a central hub, an outer ring spaced apart from the central hub, and spars, each extending radially from a proximal end, on the first jaw of the hub, to a distal end on the ring. The hub is a clamp with an open condition and a closed condition for clamping onto the cylinder, and it includes first and second jaws pivoted to each other to open and close the hub about a space configured to receive the cylinder. A latch assembly opens and closes the first and second jaws with respect to each other. 
     The above provides the reader with a very brief summary of some embodiments described below. Simplifications and omissions are made, and the summary is not intended to limit or define in any way the disclosure. Rather, this brief summary merely introduces the reader to some aspects of some embodiments in preparation for the detailed description that follows. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Referring to the drawings: 
         FIG. 1  is a front perspective view of a chair having a gas cylinder and a quick-release footrest device applied thereto; 
         FIG. 2  is a top plan view of the footrest device; 
         FIG. 3  is a rear perspective view of the footrest device; and 
         FIGS. 4 and 5  are top perspective views of the footrest device arranged in closed and open conditions, respectively. 
     
    
    
     DETAILED DESCRIPTION 
     Reference now is made to the drawings, in which the same reference characters are used throughout the different figures to designate the same elements. Briefly, the embodiments presented herein are preferred exemplary embodiments and are not intended to limit the scope, applicability, or configuration of all possible embodiments, but rather to provide an enabling description for all possible embodiments within the scope and spirit of the specification. Description of these preferred embodiments is generally made with the use of verbs such as “is” and “are” rather than “may,” “could,” “includes,” “comprises,” and the like, because the description is made with reference to the drawings presented. One having ordinary skill in the art will understand that changes may be made in the structure, arrangement, number, and function of elements and features without departing from the scope and spirit of the specification. Further, the description may omit certain information which is readily known to one having ordinary skill in the art to prevent crowding the description with detail which is not necessary for enablement. Indeed, the diction used herein is meant to be readable and informational rather than to delineate and limit the specification; therefore, the scope and spirit of the specification should not be limited by the following description and its language choices. 
       FIG. 1  is a perspective view of a chair  11  including a seat back on a seat bottom  12 , mounted to a rod  13  of a gas cylinder  14 . The rod  13  is within the sleeve  15  of the gas cylinder  14 , and the bottom of the sleeve is press-fit into a wheelbase  16 . A footrest device  10  is secured on the sleeve  15  and extends out to provide support for the feet of someone sitting on the seat bottom  12 . The device  10  includes an outer ring  20 , a central hub  21 , a plurality of structural spars  22  extending from the hub  21  to the ring  20 , and a latch assembly  23  for opening and closing the hub on the gas cylinder  14 . The ring  20  defines a footrest where the user of the chair  11  can rest his or feet apart from the gas cylinder  14 . 
     The ring  20  is constructed of a material or combination of materials having strong, rigid, durable, and rugged material characteristics, such as aluminum, steel, a like metal, carbon fiber, or other similar material. The ring  20  shown in these drawings extends along a more-than-semi-circular arc around the hub  21  of approximately two hundred twenty degrees. In other embodiments, the ring  20  is a quarter-circle, a semicircle, a full circle, or some other portion of a circle, and the embodiment shown in these drawings is not meant to be limiting. 
     The ring  20  preferably, though not necessarily, has a round or even circular cross-section, as shown in the drawings. Other embodiments of the ring  20 , however, have other cross-sections, such as square, rectangular, triangular, etc. The ring  20  is preferably solid. As shown in  FIG. 2 , the ring  20  has two opposed ends  30  and  31  and an inner surface  32  directed inward toward the hub  21 . Although the ring  20  is round and thus has no defined inner face, the inner surface  32  is generally that hemi-cylindrical portion of the ring  20  which is oriented toward the hub  21 . In other embodiments of the ring  20  in which the cross-section is another shape, such as square or rectangular, the inner surface  32  is the face directed toward the hub  21 . 
     Referring primarily to  FIG. 2 , the hub  21  is a clamp having opposed first and second jaws  40  and  41 , useful for clamping onto the gas cylinder  14 . The jaws  40  and  41  are pivoted to each other at a hinge  42  to move the jaw  40  between a closed position and an open position relative the jaw  41 , corresponding to a closed condition and an open condition of the hub  21 . In the closed position of the jaw  40 —and thus the closed condition of the hub  21 —the hub  20  bounds and defines an interior space  24  which is configured to tightly receive the gas cylinder  14 . A quick-release latch assembly  23  is pivoted to the jaw  41  to releasably couple, close, and tighten the jaw  41  with respect to the jaw  40 , so as to arrange the hub  21  between the unlocked and locked conditions. 
     The jaw  41  has a roughly semi-cylindrical sidewall with opposed ends  43  and  44 . The end  43  is a knuckle forming a portion of the hinge  42 . As best shown in  FIG. 4 , the end  44  is forked, having a medial slot  45  extending longitudinally into the jaw  41 , and including a bore  46  for receiving a pin  47 . The bore  46  extends through the forked end  44  of the jaw  41  to form two bores or sleeves that hold the pin  47 . The quick-release latch assembly  23  is pivoted in this slot  45 , as is described in greater detail below. 
     The jaw  41  includes an inner surface  48 , which is arcuate and defines an inner diameter of the jaw  41 . The inner diameter of the jaw  41  is just slightly less than the outer diameter of the sleeve  15  of the gas cylinder  14 . As such, when the hub  21  is fit onto the gas cylinder  14 , the outer diameter of the sleeve  15  is tightly received in contact against the inner surface  48  of the jaw  41 . 
     The jaw  40  is pivoted to the jaw  41 . The jaw  40  has opposed ends  50  and  51 . The end  50  is a knuckle forming the portion of the hinge  42  complemental to the knuckled end  44  of the jaw  41 , and the end  51  is a free end. A pin  52  is passed through bores formed through the ends  43  and  50  to bind the knuckled ends  43  and  50  of the jaws  41  and  40  to each other and form the hinge  42 . The jaw  40  has a roughly semi-cylindrical sidewall extending from the end  50  to the end  51 . The end  51  is forked, having a medial slot  53  extending longitudinally into the jaw  40 . The slot  53  receives a latch of the latch assembly  23  to close the jaw  40  to the jaw  41 . The slot  53  severs the free end  52  into opposed upper and lower tangs  54  and  55  (as marked in  FIG. 5 ). The jaw  40  includes an inner surface  58 , which is arcuate and defines an inner diameter of the jaw  40 . The inner diameter of the jaw  40  is just slightly less than the outer diameter of the sleeve  15  of the gas cylinder  14 . As such, when the hub  21  is fit onto the gas cylinder  14 , the outer diameter of the sleeve  15  is tightly received in contact against the inner surface  58  of the jaw  40 . Further, when the jaw  40  is in the closed position thereof, the tangs  52  and  53  rest against or are brought close to the end  43  of the jaw  41 . 
     Referring to  FIGS. 2 and 3 , the quick-release latch assembly  23  is coupled to the end  44  of the jaw  41 . The quick-release latch assembly  23  includes a cam  60  and a handle  61  formed integrally and monolithically to the cam  60 , but extending away from the cam  60 . The cam  60  and handle  61  together define a latch  66  of the latch assembly  23 . The cam  60  is formed with a bore  62  extending entirely through the cam transverse to the handle  61 . The bore  62  holds a pin  63 , about which the cam  60  and handle  61  are mounted for rotation. The bore  62  is eccentrically disposed in the cam  60 ; that is, the bore  62  is offset with respect to the geometric center of the cam  60 . 
     The pin  63  is at the end of a rod  64 . The pin  63  is mounted on the rod  64  with a threaded engagement. The pin  63  can be rotated in one direction or another to thread the pin  63  more or less onto the rod  64  and thereby translate the pin  63  down or up the rod  64  slightly, so as to change the effective length of the rod  64  slightly. With the pin  63  mounted on the rod  64 , the cam  60  and handle  61  pivot with respect to the rod  64  through a wide range of movement. The pin  47  is at the opposing end of the rod  64 . That pin  47  is carried within the bore  46  in the jaw  41 ; as such, the rod  64  pivots with respect to the jaw  41 . This allows the rod  64  to move into and out of the slot  53  defined between the tangs  54  and  55  of the free end  51  of the jaw  40 . 
     Also carried on the rod  64  is a bushing  65 . The bushing  65  is below the cam  60  and has a concave shape, such that it mates against the convex outer surface of the cam  60 . The bushing  65  is preferably constructed of a plastic such as nylon, but can be constructed of any material presenting a low friction surface in confrontation with the outer surface of the cam  60 . As mentioned above, the cam  60  is an eccentric: as the handle  61  is rotated about the pin  63 , the cam presents  60  a lesser or greater wall thickness along the direction of the rod  64 . In other words, as the handle  61  rotates, the bushing  65  is moved slightly closer to or further from the pin  63 , shortening an effective length of the rod  64  with which the jaw  40  can be captured. The bushing  65  is are interposed between the cam  60  of the handle  61  and the upper and lower tangs  54  and  55  of the jaw  40 . When the jaw  40  is in the closed position, the rod  64  is passed through the slot  54  between those tangs  54  and  55 . 
     The ring  20  is supported by the spars  22  connected to the hub  21 . The spars  22  space the ring  20  apart from the hub  20 , far apart: the ring  20  is spaced apart from the hub  20  by approximately four times the inner diameter of the jaw  41 . The ring  20  supports the feet of the person sitting in the chair, and so to support this cantilevered weight with respect to the hub  21 , the spars  22  are all constructed from a material or combination of materials having strong, rigid, durable, and rugged material characteristics, such as aluminum, steel, a like metal, carbon fiber, or other similar material. Turning to  FIGS. 2 and 3 , six spars  22  are shown. In other embodiments of the device  10 , a greater or lesser number of spars  22  may be used. The spars  22  are different: there are two outer spars  70 , two inner spars  71 , and two central spars  72 . 
     The outer spars  70  extend generally radially from the hub  20  to the ring  20  proximate the ends  30  and  31 . The inner spars  71  are adjacent to and set in from the outer spars  70 . The central spars  72  are adjacent to and set in from the inner spars  71 , and the central spars  72  are adjacent each other as well. 
     Each of these spars  70 - 72  has a proximal end  73  and an opposed distal end  74 . And the distal end  74  of every spar  70 - 72  is formed to the inner surface  32  of the ring  20  so as to permanently fix the spars  70 - 72  to the ring  20 . The proximal ends  73  of the inner and central spars  71  and  72  are formed to the outer surface of the jaw  41  of the hub  21 . The proximal ends  73  of the outer spars  70  are formed to the inner spars  71  to permanently fix the spars  70  to the inner spars  71 . The proximal end  73  of each outer spar  70  is formed on the spar  71  itself, proximate to the hub  20  but not on the hub  20 . There is a slight gap along the inner spar  71  between the jaw  41  and the proximal end  73  of the outer spar  70 . 
     Moreover, the outer spar  70  is formed to an outer face  75  of the inner spar  71 , directed toward the outer spar  70 . By setting the proximal end  73  of the outer spar  70  slightly away from the jaw  41  on the outer face  75  of the inner space  71 , the outer spar  70  creates circumferential gaps  76  between the outer spars  70  and the hub  20 . This provides room for the jaw  40  and latch assembly  23  to pivot and swing open, such that the hub  21  can be removed from the gas cylinder  14  more easily. 
     In operation, the hub  21  is useful to securely position, couple, and secure the footrest device  10  on the sleeve  15 . The hub  21  can be opened to remove the footrest device  10  from the sleeve  15  when the chair  11  is ready to be packed up and transported.  FIG. 1  illustrates the device  10  in a closed condition on the sleeve  15 . The following discussion describing how to remove the footrest device  10  is made with respect to  FIGS. 4 and 5 , which show the device  10  separate from the gas cylinder  14 , but one having ordinary skill in the art will still understand the description without the presence of the gas cylinder  14  in the drawings. 
     When the hub  20  is in the closed condition, the handle  61  is in the closed position, as shown in solid line in  FIG. 4 . The handle  61  is directed against the hub  20 , along the outer surface of the jaw  40 . In this position of the handle  61 , the cam  60  pushes the bushing  65  toward the end  44  of the jaw  41 . Because the jaw  41  is relatively fixed, and because the jaw  40  pivots with respect to the jaw  41  about the hinge  42 , placing the handle  61  into the closed position moves the jaw  40  toward the jaw  41 . Again, this is because the cam  60  is an eccentric: as the handle  61  is moved into the closed position, the cam  60  rotates to present a greater wall thickness along the direction of the rod  64 . This shortens the effective length of the rod  64 , that is, the length of the rod  64  from the end  44  of the jaw  41  onto which the free end  51  of the jaw  40  can be fit. This draws the jaw  40  closer to the jaw  41 , thereby constricting the hub  21  about the sleeve  15 . Because the jaws  40  and  41  have inner diameters just slightly less than the outer diameter of the sleeve  15  of the gas cylinder, this clamps the hub  20  tightly onto the sleeve  15 . 
     As further security, a set screw  80  is set through a bore  81  in the jaw  41 . Referring briefly to  FIG. 2 , the bore  81  is formed transversely through the sidewall of the jaw  41  and is threaded. The set screw  80  is complementally threaded, and is applied to and tightened within the bore  81  to extend through the bore  81 . The set screw  80  is tightened until its end contacts and presses against the sleeve  15  of the gas cylinder  14 , thereby preventing movement of the device  10  with respect to the gas cylinder  14 . 
     To remove the footrest device  10  from the gas cylinder  14 , the set screw  80  is withdrawn from engagement with the cylinder  14 . Then, the handle  61  is taken up, such as by hand, and moved away from the jaw  40 , along the pivotal direction of the arcuate arrowed line A in  FIG. 4 , into the position shown in that drawing in broken line. Pivoting the handle  61  about the pin  63  at the end of the rod  64  allows the bushing  65  to move slightly apart from the tangs  54  and  55  of the end  51  of the jaw  40 . This, in turn, allows the ends  51  and  44  of the jaws  40  and  41  to move apart from each other as well. This loosens the jaws  40  and  41  with respect to the sleeve  15 . The handle  61  is moved until it is at least aligned with the rod  64 , as in  FIG. 4 . At this position of the handle  61 , the bushing  65  is sufficiently apart from the tangs  54  and  55  that the rod  64  can be pivoted out of the slot  53  between the tangs  54  and  55 . 
     Next, the rod  64  is slipped out of the slot  53  between the upper and lower tangs  54  and  55  by pulling the handle  61  away from the jaw  41 , as shown by the arcuate arrowed line B in  FIG. 5 . This decouples the jaw  40  from the jaw  41 . Then, the jaw  40  can be swung out, pivoted about the hinge  42  along the arcuate arrowed line C in  FIG. 5 . The jaw  40  is swung out sufficiently so that it clears the sleeve  15 . Finally, the entire footrest device  10  can be pulled away from the sleeve  15 . Though the gas cylinder  14  is not shown in the drawings, one having ordinary skill will readily appreciate how the gas cylinder  14  can be separated from the opened hub  20  in  FIG. 5 . The footrest device  10  is now entirely decoupled, and the gas cylinder  14  can be decoupled from the seat and/or wheelbase  16  for storage. 
     The pieces of the chair  11  may then be packed and stored or shipped. When the chair  11  is to be re-assembled on site, the steps above are merely reversed. The footrest device  10  is brought close to the sleeve  15  with the jaw  40  in the open position thereof. When the jaw  41  is registered against the sleeve  15 , the jaw  40  is closed around the sleeve  15 . The latch assembly  33  is then pivoted, bringing the handle  61  over the end  51  of the jaw  40  and the rod  64  through the slot  53  between the tangs  54  and  55 . When the rod  64  is fully received in the slot  53 , the handle  61  is moved to the closed position thereof, against the outside of the jaw  40 . This tightens the hub  21  about the sleeve  15 . If the hub  21  is too tight or not sufficiently tight, the handle  61  can be opened and spun; this causes the pin  63  to threaded in or out on the rod  64  and will change the tightness of the hub  21  on the sleeve  15 . 
     A preferred embodiment is fully and clearly described above so as to enable one having skill in the art to understand, make, and use the same. Those skilled in the art will recognize that modifications may be made to the description above without departing from the spirit of the specification, and that some embodiments include only those elements and features described, or a subset thereof. To the extent that modifications do not depart from the spirit of the specification, they are intended to be included within the scope thereof.