Patent Publication Number: US-6209154-B1

Title: Multiple-stage positioner for furniture

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a multiple-stage positioner, more particularly to a multiple-stage positioner for a sofa-bed. 
     2. Description of the Related Art 
     Convertible furniture, such as sofa-bed, can serve as a sofa or as a bed, and is thus capable of making efficient use of available space. It is particularly suited for rooms having limited spaces. A conventional sofa-bed normally includes a seat frame, a back frame connected pivotally to the seat frame, and a positioner that allows the back frame to be turnable relative to the seat frame. However, most of the positioners used in the conventional sofa-beds are normally disadvantageous in that they only allow the back frame to be positioned at an inclined position about the seat frame when the sofa-bed is converted from bed to sofa, and thus lack flexibility to permit the back frame to be positioned at different inclined positions. 
     SUMMARY OF THE INVENTION 
     Therefore, the object of the present invention is to provide a multiple-stage positioner that is capable of overcoming the aforementioned problem. 
     Another object of the present invention is to provide a piece of furniture that incorporates the multiple-stage positioner. 
     According to one aspect of this invention, a multiple-stage positioner comprises: a stationary first part having front and rear ends; a second part connected pivotally to the rear end for turning relative to the stationary first part; a holding pin projecting from the first part in a direction substantially parallel to the axis of rotation of the second part; an elongated positioning piece disposed below the first and second parts and having front and rear ends, and a lower edge extending forwardly from the rear end of the positioning piece across the holding pin to the front end of the positioning piece, the lower edge having a plurality of aligned and spaced apart first grooves, the rear end of the positioning piece being connected movably to the second part, the positioning piece being capable of moving forward and downward, or rearward and upward upon turning movement of the second part, the first grooves moving past the holding pin when the positioning piece moves rearward and upward, the first grooves engaging the holding pin and locking the positioning piece against forward movement; a spring mounted on the second part adjacent to the rear end of the positioning piece to urge the positioning piece against the holding pin; and a guiding piece mounted slidably and longitudinally on the positioning piece, the guiding piece having a bottom edge substantially flush with the lower edge of the positioning piece, the bottom edge having a plurality of aligned and spaced apart second grooves, and groove-free parts between adjacent ones of the second grooves, the guiding piece being slidable relative to the positioning piece between a first position, in which the second grooves are aligned respectively with the first grooves to receive the holding pin, when the positioning piece moves rearward and upward, and a second position, in which the groove-free parts are aligned respectively with the first grooves to prevent the holding pin from entering into the first grooves and to avoid the positioning piece from being locked against forward movement when the positioning piece moves forward and downward. 
     According to another aspect of the present invention, a piece of furniture comprises: a furniture frame, and at least one multiple-stage positioner mounted on the furniture frame. The multiple-stage positioner includes: a stationary first part having front and rear ends, and a fixed support projecting downward from the rear end; a second part having one end connected pivotally to the rear end of the first part for turning between an unfolded position in which the second part is coplanar with the first part, and a folded position in which the second part turns upward relative to the first part, the second part having a bracket projecting downwardly from the second part in the unfolded position; a holding pin projecting from the support in a direction substantially parallel to the axis of rotation of the second part; an elongated positioning piece disposed below the first and second parts and having a front end, a rear end opposite to the front end and connected movably to the bracket, and a lower edge extending forwardly from the rear end of the positioning piece across the holding pin to the front end of the positioning piece, the positioning piece being capable of moving forward and downward, or rearward and upward upon movement of the second part between the unfolded and folded positions, the lower edge being notched to form pin abutment edge parts, sliding edge parts, and a plurality of aligned and spaced part first grooves, each of which is confined by one of the pin abutment edge parts and one of the sliding edge parts, the pin abutment edge parts facing toward the front end of the positioning piece, the sliding edge parts facing toward the rear end of the positioning piece, each of the sliding edge parts being inclined relative to the lower edge with an angle smaller than that formed between each of the pin abutment edge parts and the lower edge, the first grooves moving past the holding pin when the positioning piece moves rearward and upward, the first grooves engaging the holding pin and locking the positioning piece against forward movement, the lower edge of the positioning piece further having a first groove half formed anteriorly of the first grooves; a spring mounted on the bracket adjacent to the rear end of the positioning piece to urge the positioning piece against the holding pin; and a guiding piece juxtaposed and mounted slidably on the positioning piece, the guiding piece having a bottom edge substantially flush with the lower edge of the positioning piece, the bottom edge having a plurality of aligned and spaced apart second grooves, and groove-free parts between adjacent ones of the second grooves, the guiding piece being slidable relative to the positioning piece between a first position, in which the second grooves are aligned respectively with the first grooves to receive the holding pin, and a second position, in which the groove-free parts are aligned respectively with the first grooves to prevent the holding pin from entering into the first grooves, the bottom edge of the guiding piece further having a second groove half formed anteriorly of the second grooves, and a frontmost pin-engaging edge part disposed anteriorly of the second groove half, the first and second groove halves opposing and complementing one another for cooperatively receiving the holding pin when the guiding piece is in the first position, the second groove half being slidable over the holding pin, the first groove half being engageable with the holding pin, the pin-engaging edge part having a depth smaller than that of the second groove half from the bottom edge and being engageable with the holding pin immediately after the second groove half slides rearwardly past the holding pin. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In drawings which illustrate an embodiment of the invention, 
     FIG. 1 is a schematic view of a convertible sofa-bed with a multiple-stage positioner embodying this invention; 
     FIG. 2 is a partly exploded view of the multiple-stage positioner of FIG. 1; 
     FIG. 3 is a side view of the multiple-stage positioner of FIG. 1 with the positioning piece in an unfolded position; 
     FIG. 4 is a side view of the multiple-stage positioner of FIG. 1 with the positioning piece in a folded position; 
     FIG. 5 is a side view of the multiple-stage positioner of FIG. 1 with the positioning piece in another folded position; and 
     FIG. 6 is a side view of the multiple-stage positioner of FIG. 1 with the guiding piece in a second position which permits retraction of the positioning piece to the unfolded postition. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 2 to  6  illustrate a multiple-stage positioner  2  embodying this invention. FIG. 1 illustrates a convertible sofa-bed  1  that has two opposite sides, each of which is attached with one multiple-stage positioner  2 . The sofa-bed  1  has a furniture frame  10  which includes a seat frame  12  having left and right sides  121 ,  122  and front and rear ends  123 ,  124 , a back frame  13  disposed posteriorly of and connected pivotally to the rear end  123  of the seat frame  12  via the multiple-stage positioners  2  and having left and right sides  131 ,  132 , left and right leg frames  11  connected respectively to the left sides  121 ,  131  of the seat and back frames  12 ,  13  and the right sides  122 ,  132  of the seat and back frames  12 ,  13 , and left and right cross bars  14  extending respectively across the left and right leg frames  11  in a front-to-rear direction below the seat and back frames  12 ,  13 . 
     Each of the multiple-stage positioners  2  includes a stationary positioning frame  3 , an elongated positioning piece  4  having opposite front and rear ends  42 ,  41 , a torsion spring  5  having two opposite end sections  51 ,  52 , and a guiding piece  6 . 
     The stationary positioning frame  3  has a stationary first part  36  secured to one of the left and right sides  121 ,  122  of the seat frame  12  and having front and rear ends  361 ,  362 , a second part  37  secured to one of the left and right sides  131 ,  132  of the back frame  13  and having front and rear ends  371 ,  372 , a fixing plate  31  disposed longitudinally below the seat and back frames  12 ,  13  and attached securely to one of the left and right cross bars  14  at one side, an L-shaped primary fixed support  32  connected to and projecting downwardly from the rear end  362  of the first part  36  and having one end that is connected securely to the fixing plate  31  and that projects laterally therefrom, and an auxiliary fixed support  33  interconnecting securely the front end  361  of the first part  36  and the fixing plate  31 . The front end  371  of the second part  37  is disposed between and is connected pivotally to the rear end  362  of the first part  36  and the fixed support  32  via a pivot pin  321  extending through the fixed support  32 , the front end  371  of the second part  37 , and the rear end  362  of the first part  36 . The second part  37  is thus rotatable about an axis defined by the pivot pin  321 , and is turnable between an unfolded position where the second part  37  is coplanar with the first part  36 , and a folded position where the second part  37  turns upward relative to the first part  36 . A bracket  38  is secured to the second part  37 , and projects downwardly therefrom in the unfolded position. An L-shaped limit plate  39  has two opposite ends interconnecting respectively the bracket  38  and the rear end  41  of the positioning piece  4 . A holding pin  35  projects outwardly from the primary fixed support  32  in a direction substantially parallel to the axis of rotation of the second part  37 . 
     The positioning piece  4  is disposed below the first and second parts  36 ,  37  and above the fixing plate  31 , and further has a lower edge  47  extending from the rear end  41  across the holding pin  35  and the primary fixed support  32  to the front end  42  thereof. The rear end  41  of the positioning piece  4  is disposed between and is connected pivotally to the bracket  38  and one of the opposite ends of the limit plate  39  via a pivot pin  391  extending through the limit plate  39 , the rear end  41  of the positioning piece  4 , and the bracket  38  so that the positioning piece  4  is capable of moving forward and downward, or rearward and upward upon movement of the second part  37  between the folded and unfolded positions. The lower edge  47  of the positioning piece  4  is notched to form a plurality of aligned first grooves  45 , and a plurality of first groove-free parts  451  spaced apart respectively by the first grooves  45 . Each of the first grooves  45  is confined by opposite sliding and pin abutment edge parts  48 ,  49  which face respectively toward the rear and front ends  41 ,  42  of the positioning piece  4 . Each of the sliding edge parts  48  is inclined relative to the lower edge  47  with an angle smaller than that formed between each of the pin abutment edge parts  49  and the lower edge  47 . The sliding edge parts  48  permit the first grooves  45  to move past the holding pin  35 , when the positioning piece  4  moves rearward and upward. The pin abutment edge parts  49  engage the holding pin  35  and thus lock the positioning piece  4  against forward movement. A first groove half  46  is formed in the lower edge  47  anteriorly of the first grooves  45  and of the first groove-free parts  451  adjacent to the front end  42  of the positioning piece  4 , and is engageable with the holding pin  35  to prevent the positioning piece  4  from moving frontward and downward. The positioning piece  4  is formed as a channel piece which opens downwardly and which has two opposite sides  43  and a top side  44  interconnecting the opposite sides  43 . A top opening  441  is formed in the top side  44  of the positioning piece  4  adjacent to the rear end  41  of the positioning piece  4 . An L-shaped retaining plate  34  has one end connected to the primary fixed support  32  at the holding pin  35 , and the other end secured to the primary fixed support  32  above the holding pin  35 . The positioning piece  4  extends between the primary fixed support  32  and the retaining plate  34 . 
     The torsion spring  5  is mounted on the pivot pin  391  between the opposite sides  43 ,  44  of the positioning piece  4 . The opposite end sections  51 ,  52  of the torsion spring  5  project upwardly from the pivot pin  391  through the top opening  441  in the positioning piece  4  so as to abut respectively against the top side  44  of the positioning piece  4  and the limit plate  39  and to urge the positioning piece  4  against the holding pin  35 . 
     The guiding piece  6  is juxtaposed and is mounted slidably on the positioning piece  4  adjacent to the front end  42  of the positioning piece  4 . The guiding piece  6  is in the form of a longitudinally extending plate, and has a bottom edge  62  which is substantially flush with the lower edge  47  of the positioning piece  4 . The bottom edge  62  of the guiding piece  4  is notched to form a plurality of aligned second grooves  63  and a plurality of second groove-free parts  66  spaced apart respectively by the second grooves  63 . The second grooves  63  substantially conform to the first grooves  45 . A second groove half  68  is formed in the bottom edge  62  anteriorly of the second groove-free parts  66  and of the first groove half  46 . A frontmost pin-engaging edge part  67  is formed in the bottom edge  62  anteriorly of the second groove half  68 . The pin-engaging edge part  67  has a depth smaller than that of the second groove half  68  from the bottom edge  62 . The guiding piece  6  further includes two opposite spaced apart slots  61  which are elongated and are aligned in the longitudinal direction of the positioning piece  4 . Two mounting pins  7  extend respectively into the slots  61  from the positioning piece  4  so that the guiding piece  6  is capable of sliding relative to the positioning piece  4  between a first position, where the second grooves  63  are aligned respectively with the first grooves  45  and where the first and second groove halves  46 ,  68  are opposed to and complement one another to form a frontmost third groove  8  for receiving the holding pin  35  in one of the first grooves  45  and the frontmost third groove  8 , and a second position, where the second groove-free parts  66  are aligned respectively with the first grooves  45  and where the second groove half  68  is aligned with the first groove half  46  for preventing the holding pin  35  from entering into the first grooves  45  and the third groove  8 . The second half groove  68  is slidable over the holding pin  35  when the positioning piece  4  moves rearward and upward. The pin-engaging edge part  67  is engageable with the holding pin  35  so as to place the guiding piece  6  in the second position from the first position by moving the positioning piece  4  frontward and downward after the second groove half  68  slides past the holding pin  35  in the course of the rearward and upward movement of the positioning piece  4 . After the pin-engaging edge part  67  is slid frontward over the holding pin  35  by moving the second part  37  rearward and downward when the guiding piece  6  is in the second position, the guiding piece  6  will not be held by the holding pin  35  any longer, and the guiding piece  6  will thus slide downward from the second position to the first position by virtue of gravity. Therefore, in order to move the second part  37  from the folded position to the unfolded position and to allow the rearmost one of the first grooves  45  to engage the holding pin  35 , a quick frontward movement of the positioning piece  4  is necessary before the guiding piece  6  slides to the first position. 
     With the multiple-stage positioner  2 , the sofa-bed  1  of this invention can be converted from a bed to a sofa which permits the back frame  13  to be inclined relative to the seat frame  12  at different angles. 
     With the invention thus explained, it is apparent that various modifications and variations can be made without departing from the spirit of the present invention. It is therefore intended that the invention be limited only as recited in the appended claims.