Abstract:
A height-adjustable sewing table, having a flat tabletop providing a work surface for piece goods and craft items being sewn. The tabletop is supported by a pair of height-adjustable leg assemblies, having a base, a tubular column and an extendible member with one ends which registers with the tubular column. The other end of the extendible member engages and articulates with the undersurface of the tabletop. An opening is provided in the tabletop, into which a sewing machine mounted on a platform is raised from or lowered into a position from below the tabletop by a lifting mechanism. The lifting mechanism preferably has mast mounted vertically and a carriage which rides vertically along the mast. The platform is mounted on the carriage. The carriage may be moved manually or with pneumatic or electrical power assistance. Likewise, the extendible members of the leg assemblies may be extended manually or with pneumatic or electrical power assistance.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority under 35 U.S.C. §119(e) from U.S. Provisional Application No. 60/709,144, filed under 35 U.S.C. 111(b) on Aug. 16, 2005, entitled “Height-Adjustable Sewing Table”. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to tables for supporting sewing machines.  
         [0004]     2. Description of the Prior Art  
         [0005]     Sewing machines are a common type of machinery used in the garment industry and by individuals for arts, crafts and creating and repairing garments.  
         [0006]     Sewing machines owned by individuals may be portable. A portable machine is stored in a case kept in a storage location, such as a closet, when not in use. It is then set up on a table or other work surface when placed into operation. When the sewing operations are complete, the machine is returned to its case and the case returned to its storage location.  
         [0007]     Sewing machines may also be installed essentially permanently in a sewing cabinet. The sewing cabinet serves as both storage and as a work surface for the sewing machine. The sewing cabinet is typically a fixed cabinet, usually stylized to some degree to match or coordinate with other furniture in a room. The sewing cabinet provides a work surface, usually on the top of the cabinet, on which the sewing machine is mounted or positioned. When the sewing machine is not in use, means are provided by which the sewing machine may be easily retracted or lowered below the work surface and into the interior space of the cabinet for storage. When the sewing machine is to be put to use again, the same means elevates or otherwise resituates the machine back to the work surface on top of the cabinet.  
         [0008]     Several means for resituating the sewing machine in the cabinet exist in the relevant art. For example, a traditional type of means involved an articulating or pivoting base attached to the cabinet, upon which the machine was mounted. In storage, the sewing machine is stored on its side, horizontally, within a well or other space inside the cabinet. To place the machine into use, the machine and its platform are pivoted upward to a vertical attitude. Such pivoting machine platform designs are illustrated in U.S. Pat. No. 1,462,271, issued to Ennis on Sep. 26, 1922, U.S. Pat. No. 4,005,918, issued to Smith et al. on Feb. 1, 1977; U.S. Pat. No. 4,108,512, issued to White on Aug. 22, 1978; and U.S. Pat. No. 4,253,715, issued to Greiner on Mar. 3, 1981.  
         [0009]     One disadvantage typically found in these pivoting platform designs is a limitation to a single working height for the sewing machine. In other words, in these pivoting platform designs, the platform, when swung into its operational attitude or position, is limited to one height. This limitation may decrease the utility of the sewing machine mounted thereon. Typically, sewing machines are used in two configurations. One configuration is flatbed sewing, where the work surface surrounding the sewing machine is level with the sewing surface of the machine, that is, the surface containing the presser foot and platens where the fabrics are stitched together by the sewing needle. This configuration is desirable when sewing large flat panels of fabric, such as curtains or drapes. The other configuration is free-arm sewing, where the free-arm part of the sewing machine, on the top surface of which is disposed the sewing apparatus, is elevated above the work surface. This configuration is useful for sewing cylindrical articles, such as sleeves and the like.  
         [0010]     To overcome this disadvantage, some pivoting platform type sewing cabinets attempt to provide means for two positions for the upright platform. For example, U.S. Pat. No. 3,986,755, issued to Kohara on Oct. 19, 1976, teaches of a mechanism for pivoting a sewing machine platform into one of two upright positions using a pair of vertically sliding hinge assemblies.  
         [0011]     Another type of sewing machine lifting mechanism involves some form of direct vertical translation or lift of the platform, without articulation or pivoting. Examples of this type include U.S. Pat. No. 3,870,386, issued to Shepherd on Mar. 11, 1975; U.S. Pat. No. 3,993,008, issued to Parsons, Sr. on Nov. 23, 1976; and U.S. Pat. No. 4,690,466, issued to Bakr et al., on Sep. 1, 1987. These typically teach of a mechanism comprising a track within which the platform translates vertically by some power source, having two upper positions provided at the desirable heights for free-arm or flatbed sewing modes.  
         [0012]     In typical cases, the cabinet is mounted on legs or has an open lower section made available by a front door in the cabinet. This allows the operator of the sewing machine to sit close to the cabinet with her legs under the storage area of the machine. This generally provides the sewing machine at a comfortable height and position for many operators seated before the sewing cabinet. However, the height of the work surface is typically not adjustable. The fixed height of the work surface of the sewing cabinet is often inconvenient and uncomfortable for very short or very tall operators. Sewing machine cabinets also do not usually accommodate special seating arrangements, such as wheelchairs. A sewing table in which the height of the work surface is adjustable as well as the height of the sewing machine with respect to the work surface is desirable.  
       SUMMARY OF THE PREFERRED EMBODIMENT  
       [0013]     To overcome the limitations found in the prior art, disclosed is a sewing table with a platform for vertically positioning a sewing machine between a work surface and a storage position, and with a work surface also capable of vertical position adjustment.  
         [0014]     The sewing cabinet comprises a work surface or table top, mounted on a pair of height-adjustable leg assemblies. Each of the leg assemblies is comprised of a cantilevered base, a tubular column and an extendible member which registers and engages the hollow interior section of the tubular columns. The tabletop is mounted on brackets on the top end sections of the leg assembly extendible members. The extendible sections of the leg assemblies may be extended by manual or by powered means.  
         [0015]     Underneath the tabletop is mounted a sewing machine lift mechanism to raise a sewing machine platform, and a sewing machine mounted thereon, from a storage or concealed position below the tabletop to one or more operating positions above the tabletop. The operating positions would include one for flatbed sewing and another for free-arm sewing.  
         [0016]     The combination of height adjustments for both the sewing machine platform with respect to the work surface, as well as the work surface with respect to the operator, provides flexibility for accommodating the needs of nearly all sewing machine operators. The work surface can be adjusted to accommodate the comfort of all sewing machine operators, including those in wheel chairs, as well as those wishing to stand rather than sit before the sewing cabinet.  
         [0017]     One embodiment of the invention includes a table top which can be tilted towards the operator, typically by about 5 degrees. This permits the operator&#39;s line of sight to be orthogonal to the work surface and directly above the sewing needle of the sewing machine, which facilitates more accurate seams, without having to uncomfortably bend over the work surface and sewing machine.  
         [0018]     These and other advantages of the invention will become apparent from the description which follows. In the description, reference is made to the accompanying drawings, which from a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be protected. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.  
         [0019]     The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0020]      FIG. 1  is a front isometric view of the height-adjustable sewing machine cabinet.  
         [0021]      FIG. 2  is a front elevational view of the height-adjustable sewing machine cabinet.  
         [0022]      FIG. 3  is a side elevational view of the height-adjustable sewing machine cabinet.  
         [0023]      FIG. 4  is a front isometric illustration of the leg assemblies.  
         [0024]      FIG. 5  is a perspective illustration of the bracket at the upper end section of the leg assembly.  
         [0025]      FIG. 6  is a side elevational view, showing one embodiment for height adjustment of the leg assemblies.  
         [0026]      FIG. 7  is a side elevational view, showing another embodiment for height adjustment of the leg assemblies.  
         [0027]      FIG. 8  is a side elevational view, showing another embodiment for height adjustment of the leg assemblies.  
         [0028]      FIG. 9  is a side elevational view, showing another embodiment for height adjustment of the leg assemblies.  
         [0029]      FIG. 10  is a rear elevational illustration of one embodiment of the sewing machine platform lift mechanism, as seen from the rear view.  
         [0030]      FIG. 11  is a side elevational view of the height-adjustable sewing machine cabinet, illustrating a titled table top.  
         [0031]      FIG. 12  is an illustration of the leg assembly brackets arranged for a tilted table top. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]     The following discussion describes in detail one or more embodiments of the invention. The discussion should not be construed, however, as limiting the invention to those particular embodiments, and practitioners skilled in the art will recognize numerous other embodiments as well. The complete scope of the invention is defined in the claims appended hereto.  
         [0033]     As shown in  FIGS. 1, 2  and  3 , a height-adjustable sewing table  10  comprises, generally, a tabletop  12  which has a planar upper surface providing a flat and level work surface for sewing. Within the tabletop  12  is defined an opening  14  which provides a passage through which a sewing machine  30  can be elevated from a stored position under the tabletop  12  to a working position.  
         [0034]     The tabletop  12  is mounted on a pair of leg assemblies  16 . Each leg assembly  16  can extend in unison with the other to elevate the tabletop  12  to varying heights, as desired. Each of the leg assembly  16  are typically made of a base  18 , a tubular column  20  and a extendible member  22  which registers within a channel within the tubular column  20 .  
         [0035]     The sewing machine  30  is mounted on a sewing machine platform  28 . The sewing machine platform  28  is in turn mounted upon a sewing machine platform lift  32  which raises and lowers the sewing machine platform  28 , and, in turn, the sewing machine  30  between its stored or concealed position below the tabletop  12  and its operating position at or above the tabletop  12 . The sewing machine platform lift  32  is mounted upon a back panel  38 , which is in turn mounted to the underside of the tabletop  12 . Two side panels provide additional support and rigidity for the sewing machine platform lift  32 .  
         [0036]     The tabletop  12  forms a work surface for use with a sewing machine  30  (shown in  FIG. 2 ). The tabletop  12  has an upper surface which is planar and substantially flat. It is typically rectangular, as is typical in the art, having a width and a length dimension. It further has a thickness, the dimension of which varies to provide reasonable stiffness and minimal deflection of the tabletop  12  according to its length and width dimensions and its method and material of construction. Typically, the tabletop  12  is fabricated of a core panel made of wood or a wood product, such as plywood, particleboard or medium-density fiberboard. A skin is typically applied to the upper face of the core panel to provide a hard, smooth work surface. Typical skins include laminates of various polymeric resins.  
         [0037]     Within the perimeter of the tabletop  12  is defined an opening  14 . The sewing machine  30  passes through the opening  14  as it is elevated by the sewing machine platform lift  32 . The opening  14  receives the sewing machine platform  28  when it is raised to its maximum vertical extent to position the sewing machine  30  for free-arm operation. The opening  14  is sized congruent to the sewing machine platform  28  to receive it without gaps between the perimeters of the two. The opening  14  is located near the front edge of the tabletop  12 , which is the edge of the length dimension proximate to where the operator would be positioned or seated. The opening  14  may be centered on the length dimension, or may be shifted towards the right end of the length dimension (as viewed from the direction of the positioned operator), to provide greater area as a work area for the piece-goods being sewn, as preferred by right-handed operators. For left-handed operators using a left-handed sewing machine, the opening may be shifted towards the left end of the length dimension.  
         [0038]     The tabletop  12  is supported on a pair of leg assemblies  16 . In addition to  FIGS. 1-3 , the details of the two leg assemblies  16  is better illustrated in  FIG. 4 . In the preferred embodiment, each leg assembly  16  is comprised of a base  18 , a tubular column  20  and an extendible member  22 . The base  18  is an inverted cantilevered member disposed orthogonal to the axis between the two leg assemblies  16 , having pads, feet, or preferably casters  52  at either end of the underside of the base  18  A tubular column  20  is disposed medially on the base, with one end section rigidly engaged orthogonally to the base  18 . The column  20  may be connected to the base  18  removably using fasteners such as screws, or permanently using welding or brazing.  
         [0039]     The column  20  is hollow with its interior defining a longitudinal channel and is open at the end opposite from the base  18 , providing access into the channel. An elongated extendible member  22  has a cross section congruent with the cross section of the channel of the column  20 , and an end section which registers with the channel. This permits the column  20  to longitudinally transit through the channel, extending from or retracting into the channel to vary the combined overall length of the base  18  and column  20 .  
         [0040]     The other end of the column  20  opposite from the base  18  engages with the tabletop  12  on the underside, or side reverse from the work surface. The column  20  may engage with the tabletop  12  orthogonally and rigidly, to provide a level work surface when the height-adjustable sewing table  10  is assembled and posited on a floor. Alternatively, as better illustrated in  FIG. 5 , the end section of the column  20  may articulate with the underside of the tabletop  12  using an adjustable bracket. The bracket comprises a pair of “U” shaped channels, one of which is smaller and nests within the interior of the larger. The two channels articulate around a pivot axel, which permits the tabletop attached to the upper, smaller channel to tilt from a horizontal position downward towards the front of the sewing table. This provides for tilting the tabletop  12  towards an operator. By tilting the tabletop  12 , its work surface can be presented perpendicular to the line of sight of an operator standing or sitting before the front edge of the height-adjustable sewing table  10 . This presentation provides greater accuracy when sewing fine or detailed stitches on the sewing machine  30 . Generally, a tilt of five degrees is sufficient to comfortably align the tabletop surface orthogonally with the line of sight of an operator  
         [0041]     Returning to  FIG. 4 , the two leg assemblies  16  are further supported with leg braces  50 . The leg braces  50  prevent lateral splaying of the leg assemblies  16  and racking of the tabletop  12 . Two leg braces  50  are typically provided, each comprising a tubular member with a rectangular cross section mounted on the back side of the leg assemblies  16  opposite from the position of the operator to prevent interference with the legs of the operator.  
         [0042]     By providing a extendible member  22  in linear, sliding engagement with the channel in the column  20 , the overall height of the leg assemblies  16  may be varied to bring the height of the tabletop  12  of the height-adjustable sewing table  10  suitable for the needs of the operator.  
         [0043]     Various means may be provided for extending, retracting or securing the two leg assemblies  16  simultaneously to posit the work surface of the tabletop  12  at various desired heights. In one simple embodiment, shown in  FIG. 6 , the column  20  has a spring-activated button  60  which operates laterally and which can engage one of a plurality of holes  62  equally spaced longitudinally up the length of the wall of the extendible member  22 . An operator presses in on the button, or pushes down or lifts up on the tabletop  12  with enough force to dislodge the button from engagement with its present hole, and then manually lifts or lowers the tabletop  12  to a new desired height.  
         [0044]     In another embodiment, shown in  FIG. 7 , a mechanical means of assistance is provided for manually adjusting the height of the tabletop  12 . A gear rack  42  is provided along the length of each extendible member  22  and a pinion gear  44  is disposed on each column  20 , in engagement with the gear rack on the extendible member  22 . A crank  64  axially engages both pinion gears. Turning the crank manually rotates both pinion gears, which translates the gear rack and extends or retracts the extendible member  22 . Once the tabletop  12  is posited at a desired height, the extension of the extendible members  22  is secured by the friction of the gear assembly or by providing a spring latch (not shown).  
         [0045]     In another embodiment, shown in  FIG. 8 , an electric motor  48  is provided instead of a hand crank for adjusting the extension of the leg assembly  16 . A rack and pinion gear assembly is provided as in the prior manual method. But, rather than operating the two pinion gears by a manual crank, a reversible electric motor and shaft is provided. Operation of the electric motor rotates the shaft, which in turn rotates the two pinion gears, extending and retracting the extendible members  22  as before. A hand-held controller is provided for operating the motor, in either the forward or reverse directions. The controller may be mounted on the height-adjustable sewing table  10 , or may be tethered at the end of a cable for greater portability.  
         [0046]     In another embodiment, shown in a pneumatic means of assistance is provided for manually adjusting the height of the tabletop  12 . In this embodiment, the cross section of the channel in the column  20  provides space for both the extendible member  22  and a pneumatic spring  46 . The pneumatic spring is a device capable of longitudinal elongation and having an internal sealed cylinder capable of longitudinal contraction or expansion, such as by a piston registering within the bore of the cylinder. The pneumatic spring is pre-charged with a gas to a specified pressure. One end of the pneumatic spring engages the bottom of the hollow channel in the column  20  while the other end engages the bottom of the extendible member  22 . The pressure in the two cylinders is specified to provide enough force to raise the weight of the tabletop  12  together with the accessories attached thereto to the full desired extension of the extendible member  22 . The tabletop  12  is lowered by the operator pressing down on the tabletop  12  with her body weight. The added weight of the operator forces the retraction of the pneumatic cylinder and the extendible member  22 , thereby lowering the tabletop  12 . Catches or latches may be provided to secure leg assemblies  16  at the new, desired height.  
         [0047]     Returning to  FIG. 2 , a sewing machine is raised or lowered from under the tabletop  12  into or out of the one of two operating positions. Typically, a sewing machine  30  is positioned at one of two levels with respect to the surrounding work space, for performing what is referred to in the art as either “flat” or “free-arm” sewing. In flat sewing, as shown in  FIG. 2 , the sewing machine platform is raised by the sewing machine lift to a position below the tabletop  12 . The sewing machine is positioned so that its sewing surface, the surface where the needle engages the fabric under the presser foot and which is located on the top surface of the free arm of the sewing machine, is level with the surrounding work surface. The free arm is situate below the work surface. This position is more desirable for large, flat panels of fabric, as the material can be stretched out flat around the sewing machine without folds or rolls.  
         [0048]     In free-arm sewing, not shown, the sewing machine platform is further elevated by the sewing machine platform lift to register with the opening  14 . The top surface of the sewing machine platform is coplanar with the work surface of the tabletop  12 . The base of the sewing machine is level with the surrounding work surface, thereby exposing the free arm. The sewing surface on top of the free arm is elevated above the surrounding work surface. This position is more desirable when sewing closed, tubular pieces, such as sleeves. It is also desirable when changing the bobbin of the sewing machine  30 .  
         [0049]     To provide positioning of the sewing machine between the three desired positions, i.e., stored, flat-bed and free-arm sewing, a sewing machine platform lift  32  is provided under the tabletop  12  which can raise or lower a sewing machine platform  28  orthogonally to the tabletop  12 . In the preferred embodiment, the sewing machine platform lift  32  is comprised of a mast  34  and a carriage  36  which traverses along the mast  34 . The mast  34  guides the linear movement of the carriage  36  orthogonal to the tabletop  12 , moving the carriage  36  up towards or down away from the work surface of the tabletop  12 . The carriage is disposed upon the mast so as to provide means for mounting a sewing machine platform  28 , adapting for mounting a sewing machine  30  parallel to the upper work surface of the tabletop  12 . The mast is secured by lift mounting brackets  40  to a back panel  38  which is in turn secured to the underside of the tabletop  12 , and aligned so that the sewing machine platform  28  registers with the opening  14  in the tabletop  12  when the carriage  36  is elevated on the mast  34 . Additional side panels  39  may be provided orthogonally at either side edge of the back panel  38  to provide additional structural support and rigidity.  
         [0050]     Several means may be utilized for traversing the carriage  36  along the mast  34 . As better shown in  FIG. 10 , a threaded rod  54  traverses between the two lift mounting brackets  40 , parallel to the masts  34 . The carriage  36  has a threaded collar  56  engaging the threaded rod  54 . The screw is rotated, preferably by an electric motor  48  or by a crank or handle (not shown) at the bottom of the screw. The rotational motion of the threaded rod  54  is converted to linear motion by the threaded collar  56 , which translates the carriage  36  along the length of the mast  34 , positioning the sewing machine platform at a desired height. The electric motor is reversible, to use it to both raise and lower the sewing machine platform  28 . Friction and the large mechanical advantage between the screw and the collar are sufficient to hold the sewing machine platform  28  at a desired position.  
         [0051]     The tabletop  12  of the height-adjustable sewing table  10  may be tilted downward, as shown in  FIGS. 11 and 12 , towards an operator seated or standing before the front edge of the tabletop  12 . Preferably, the tabletop should be capable of tilting by at least an angle of 5 degrees. This angle places the plane of the tabletop  12  so that an operator may place her line of sight directly above the sewing needle in the sewing machine, orthogonal to the tabletop  12 , without bending uncomfortably. As shown in  FIG. 11 , when the tabletop  12  is tilted, all assemblies conjoined on the underside of the tabletop  12 , such as the sewing machine platform lift  32 , are tilted as well, so that the line of movement of the sewing machine platform remains orthogonal to the plane of the tabletop  12 .  
         [0052]     The tabletop  12  is tilted by the bracket  26  at the distal end  24  of the extendible member  22 . The two “U” channel sections of the bracket  26  articulate about a pivot axle  66 . The pivot axle  66  in the two brackets  26  on either leg assemblies  16  are aligned coaxially so that the tabletop  12  tilts smoothly about that axis. The pivot axles  66  may have threaded bolts (not shown) which may be tightened to secure the tilt of the tabletop  12  at a desired attitude.  
         [0053]     In addition to the sewing machine platform lift, other sewing accessories may be provided on the underside of the tabletop  12 . For example, as shown in  FIG. 1 , a cabinet of drawers  58  may be provided for storing extra spools of thread, sewing needles, scissors and various presser foot attachments for accomplishing various types of stitches on the sewing machine. These cabinets may be fastened to the underside of the tabletop  12  using screws or other fasteners known in the art.  
         [0054]     While various embodiments of the invention have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail may be made therein without departing from the spirit, and scope and application of the invention. This is especially true in light of technology and terms within the relevant art that may be later developed. Thus, the present invention should not be limited by any of the above-described exemplary embodiments, but should only be defined in accordance with the appended claims and their equivalents.