JPH0127723Y2 - - Google Patents

Description

[Detailed description of the invention] The present application relates to a lifting mechanism that can easily adjust the height position of the backrest of a chair.
Conventionally, a fixed column is provided vertically at the rear end of the seat, and an elevating column having a backrest at the upper end is slidably inserted into this fixed column, and one engagement hole provided in the fixed column is inserted. and an actuating member having an engagement pin at its tip that engages and disengages from a plurality of engagement holes provided in the elevation support, and is vertically rotatably attached to the seat side via a spring plate. The mechanism is known, for example, in Japanese Utility Model Publication No. 47-33778.

However, according to the above-mentioned known elevating mechanism, since the actuating member is provided on the fixed side, when raising and lowering the backrest, one hand presses the actuating member while the other hand lifts and lowers the backrest. As a result, handling is troublesome and the backrest cannot be adjusted up and down while seated, and the engagement pin is engaged and disengaged from the engagement hole by pressing the operating member manually. Since the arc movement is performed by the arc movement, it is necessary to set the vertical width of the engagement hole to be larger than the thickness of the engagement pin in proportion to its length. Therefore, in the engaged state, there is no vertical play in the backrest. There was an inconvenience that it caused sticking.

Therefore, the present application proposes a backrest lifting mechanism that can eliminate the above-mentioned inconveniences.The embodiments of the present application will be described below in detail with reference to the drawings. A fixed column consisting of a cylindrical body with an elliptical cross section that stands upright.
A plurality of rectangular engagement holes 2, 2, . . . are provided on the rear surface at required intervals in the vertical direction. Reference numeral 3 denotes an elevating column that is slidably fitted into the fixed column 1 through spacers 4, 4, and the upper end of the elevating column 3 has a convex curve on the left and right sides, respectively. The central part of the support plate 6, which has a pair of horizontally opposing bearing holes 5 in the parts 6a and 6b, is fixed together, and the side edge of one curved part 6a of the support plate 6 extends diagonally rearward. A slit 8 extending vertically is provided at an end of the support portion 7, that is, at a position offset laterally from the vertical arrangement position of the engagement holes 2. It is being Reference numeral 9 denotes a back mounting plate that is attached to the center of the rear surface of the backrest 10. Bearing pieces 11, 11 are provided at the left and right positions of the back support plate 9 to protrude rearward by cutting and raising, and bearing holes 12 provided in these bearing pieces 11, 11 are provided. , 12 and bearing holes 5, 5 provided in the support plate 6, and a shaft 13 is inserted and supported, so that the backrest 10 is attached to the upper end of the lifting column 3 so as to be swingable in the vertical direction. ing. Reference numeral 14 denotes an operation plate extending in the left-right direction and having a dogleg-shaped cross section and having a horizontal portion 14a and an inclined portion 14b, and the inclined portion 14b is supported by the slit 8 so as to be tiltable. The lower end of the horizontal part 14a extends vertically, and a locking claw 17 that selectively engages with the engaging holes 2, 2, etc. is bent slightly downward at the lower end of the horizontal part 14a. provided, and the upper end 1
A wide part 15 having a horizontal shoulder part 16 is formed on the side, and a circular push button 18 is provided on the back side of the side end of the inclined part 14b. 19 is provided between the side portion of the bearing piece 11 and the inclined portion 14b of the operation plate 14 so as to press the operation plate 14 and maintain the engagement between the locking pawl 17 and the engagement hole 2. An intervening urging spring 20 is provided protruding from the rear surface of the upper end of the fixed column 1, and a stopper that comes into contact with the shoulder 16 of the operation plate 14 to prevent the lifting column 3 from coming off from the fixed column 1; 21 is a cushion member interposed between the back mounting plate 9 and the support plate 6, and 22 is a cover stretched over the back surface of the back mounting plate 9 so as to surround the push button 18 and the rest.

However, when lifting the backrest 10, the backrest 10
lift upward. Then, since the locking claw 17 is inclined downward, the upper surface of the locking claw 17 is pressed against the upper surface of the engagement hole 2, and the operation plate 14 is moved to the inclined part 1.
4b and the slit 8 as a fulcrum, horizontally rotates in the back direction against the biasing spring 19, and the engagement hole 2
The locking pawl 17 is automatically removed from the seat to enable the backrest 10 to be lifted. When the backrest 10 is lifted up at a desired height position, any engagement hole 2 and the locking claw 17 are engaged by the elastic pressure of the biasing spring 19, and the backrest 10 is fixed to the fixed support 1. be done. Next, when lowering the backrest 10, the push button 18 is pressed against the biasing spring 19. Then, the operation plate 14 horizontally rotates in the rear direction using the engagement portion between the inclined portion 14b and the slit 8 as a fulcrum, and the locking pawl 17 engages the engagement hole 2.
In this state, for example, with the back support 10 and the push button 18 being held between the thumb and forefinger, lower the back support 10 to a desired height position, and press the push button 18.
When the pressure is released, the operation plate 14 is restored by the biasing force of the biasing spring 19, the locking pawl 17 engages with any engagement hole 2, and the backrest 10 is moved against the fixed support 1 at that height position. Fixed.

As described above, according to the present application, on the side of the backrest that goes up and down,
Since the operation panel is provided, the height of the backrest can be adjusted while pressing the push button. Therefore, the height position of the backrest can be adjusted even when the user is seated, which is very convenient. According to the above, at a position offset laterally from the vertical arrangement position of the plurality of engagement holes,
Since the operation plate is supported so as to be horizontally rotatable, the locking pawl can smoothly engage and disengage from the engaging hole, and there is no need to provide vertical clearance between the locking pawl and the engaging hole. This has the advantage that there is no risk of rattling of the backrest in the engaged state.

[Brief explanation of drawings]

The drawings show an embodiment of the present application, and FIG. 1 is a rear view;
FIG. 2 is a longitudinal sectional view, and FIG. 3 is a sectional view taken along the line I--I. In the figure, 1 is a fixed column, 2 is an engagement hole, 3 is a lifting column, 10 is a backrest, 14 is an operation plate, 17 is a locking claw,
18 is a push button, and 19 is a biasing spring.

Claims (1)

[Scope of claim for utility model registration] (1) A backrest is attached to the upper end of a cylindrical fixed support that extends upward from the rear end of the seat and has a plurality of engagement holes arranged in the vertical direction of the rear surface. In addition to slidingly inserting the elevating support, the upper part of the elevating support is
The intermediate position of the operation plate is supported by a vertical slit at a position offset laterally from the vertical arrangement position of the plurality of front and rear engagement holes, and is mounted horizontally rotatably. A locking pawl that selectively engages with the engagement hole, and a push button for horizontally rotating the operation plate are provided at the upper end, and the operation plate is pressed to connect the locking pawl and the engagement hole. A backrest lifting mechanism comprising a biasing spring that maintains engagement. (2) The backrest elevating mechanism according to claim 1, wherein the locking pawl is formed by bending the lower end of the operation plate slightly forward and downward.