FR2737518A1 - Laterally retractable frame for staircase - comprises half steps with two rungs rotating on central mounting raised on stringers where they are retracted, plates at rung ends form hinge receiving spindles on which rungs rotate - Google Patents

Abstract

The retractable staircase comprises half steps each with two rungs (6) rotating on a central mounting raised on wooden stringers where they are retracted. The U sectioned stringer is formed from a thin web (1) connecting the sides (2). The central H section mounting is also formed by a web connecting the two sides. Plates (3,4) fixed at the ends of the rungs form a hinge which receive the spindles (7) on which they rotate. From one side the spindle extensions penetrate into drillings (8) in the sides of the stringers and the central mounting. From the other side their heads are supported in a notch (10) in the web of a corner piece (9). The force for raising the rungs is reduced by a flexible brake arm fixed on the rear of one of the stringers.

Description

 The present invention relates to the improvement of the laterally retractable staircase, the subject of Patent FR X 93 02729, which comprises half-steps, each in several bars (generally two), which retract by pivoting on the one hand on an upright central which is raised and, on the other hand, on two stringers. These strings with a "U" profile, generally made of wood, are formed of a thin web connecting two banks sized to support the thrust of the steps. This push is exerted by an extension of the spindles-axes leaving the knuckle of the sides fixed at the end of the bars of steps. These extensions penetrate into the holes which were formed in the banks before the gluing of the rebate veil. The flanks are the male flanks of strong hinges which are joined by their knuckles to female flanks which, themselves, are connected by two by a intermediate plate, flat on the sails and on the central upright.

 An improvement consists in mounting at the end of the bars flanks, the realization of which is simple: rectangular plate with a winding over the entire depth and into which the spindle penetrates. It is therefore supported as above on one side, by its extension, in a bank but, on the other side, the support is made on a small angle from top to bottom and fixed in several points on the veil by one of its wings so that the other wing, perpendicular to this veil, is equidistant from the banks. Notches, of opening equal to the diameter of the axes, were released, generally by punching, on this wing, facing the bores of the two banks. The pins once entered into the knuckles are engaged in these notches and then forced into the holes until their heads come into contact with the angle iron. Xth attachment on each side of the central upright, the cross section of which is a UHU (plywood veil glued in a slot made in the axis of the front and rear banks). Drillings are carried out on their internal face before bonding to receive the extensions of the pins. Two notched angles go from top to bottom, in the middle and on both sides of the veil, secured at several points. The bars are therefore connected to the upright in the same way as to the stringers.

 Four notched angles per staircase, all identical and quick to install, advantageously replace many female sides. As for the sides on bars, they are simple to make and, moreover, the support is made over the entire length of the knuckle and not only on a part.

 Finally, it is known that a flexible arm compensates for the weight of the elements with vertical displacement. An improvement is brought by the addition, on the top slide, of a small spring acting at the end of opening, Its action combined with that of the flexible arm facilitates maneuvers.

 Other characteristics and advantages will appear on reading the description - the arrangement of certain elements will reverse according to the direction of sliding. Variations are possible without departing from the scope of the invention, in particular in the choice of materials. In the drawings: - Figure 1 is an internal side view of a straight stringer section.

- Figure 2 is the top view.

- Figure 3 a front view of 2 bars across the width of a step.

- Figure 4 shows the mounting of 2 bars on a left stringer.

- Figure 5 is a section of the central upright normal to its rear bank.

- Figure 6 is a front view of the staircase, "broken" steps.

- Figure 7 a front view of the passage in maximum width.

- Figure 8 a front view in opening, steps horizontally.

In these various figures, the references are as follows: - (1) the veil of the "U" of silt.

- (2) dNi 'lU "wings.

- (3) A sidewall at the end of the front bar - (4) A sidewall at the end of the rear bar.

- (5) A section of "Uz fitting the end of the bar.

- (6) A walking bar.

- (7) A spindle-axis.

- (8) A hole receiving the spindle-axis.

- (9) A notched angle iron.

- (10) A notch of angle iron.

- (11) The veil of the central upright.

- (12) the front edge of the central upright.

- (13) the rear bank.

- (14) the flexible arm.

- (15) the stop.

- (16) the fixed stringer.

- (17) the mobile stringer.

- (18) the support fitting on slide and sliding of the movable stringer.

- (19) the support post for the ramp and the folding railing.

- (20) the spring retaining the movable stringer.

- (21) the sliding slide.

- (22) the board forming a pivoting step (reversible).

- (23 the pivot hinge on a fixed stringer.

- (24) the pivot hinge on the chevet (swappable).

- The step top is in the AA plane.

 In the embodiment according to FIGS. 1, 2 and 3, the stringers consist of a thin web (1), generally made of plywood, glued in rabbets on wooden edges (2) forming the wings.

These banks, of rectangular section, are dimensioned to support the thrust of the articulation pins. An offset determined by the slope of the staircase is respected between the sides of the front (3) and rear '4) bars of a step. These flanks are screwed to the ends of the step bars - with the interposition of metal "U" sections (5) to avoid bursting. The bars (6) whose section is a parallelogram are mounted on the right as on the left, a rotation of 180 allowing, flanks in place, the permutation from top to bottom of the knuckles. These flanks are therefore all similar: rectangular plate with a winding over the entire length forming a knuckle in which the spindle (7) penetrates. The knuckles are wound outwards - relative to the bars -: stringer side, top, side central upright, below. The bar making with the side an angle determined by the slope of the staircase, the drilling of the sides will be for one half oriented to the right and for the other half to the left.

 3rd holes (8) are made on the inside of the edges before bonding. Their diameter is chosen so that the pins (7) re-enter by force and cannot come out of themselves (it will however be possible to drive them out if necessary, for dismounting the step, by striking with a tool under the head of the spindle ). These holes must not lead to the exterior and their spacing depends on the slope and the step height; the offset of the drillings of the front and rear banks is the same as that of the flanks. The pushing of the pins does not weaken the wood on the banks.

 A small angle iron (9) going from top to bottom is fixed at several points on the veil (1) by one of its wings so that the other wing, perpendicular to this veil, is equidistant from the banks. Notches (10) are released, on this wing1 facing the holes (8) of the two banks. Figure 4 shows that the pins (7) once advanced in the knuckles are engaged in these notches (10) and then driven into the holes (8) until their heads come into contact with the angle iron (9). A simple drilling of the angle iron to the diameter of the spindle facing the knuckle would not allow mounting. the space between angle iron and edge which is much less than the length of a spindle, not allowing this to be introduced. We therefore crunch by opening the hole up to the edge of the wing of (9) to be able hire him. Genera: in any case, by punching, a notch (10) equal to the diameter of (8) with a semicircular bottom will be released where this pin will be pressed without stressing towards the outside of the angle since guided in the bore (8 >.

 Figure 5 is a section of the central upright of section in "H": a plywood sheet (11) glued in slots formed in the axis of the front (12) and rear (13) edges. Before gluing, holes (8) were made similar to those of the edges (2). They are arranged to, in the open position, the steps being flat, receive the pins of the sides to be connected to the central upright. These pins are offset downwards with respect to those of the other end of the bar by the height of a sidewall (center distance between pin at the top of the side of the stringer side and the pin at the bottom of the upright side). Two angles (9) secured at several points through the veil (11) go from top to bottom and on both sides, one wing being centered in the middle. Notches (10) are released facing the holes in the front edges (12) and rear (13). The bars (6) having generally first been connected to the stringers, the free sides will be attached to the central upright by the pins (7) according to the same process as for the stringers. In Figure 5, a pin (7) has been shown depressed.

 Furthermore, it is known that a flexible arm ('4), Figures 6 to 8, generally made of fiberglass, is fixed obliquely on the back of one of the stringers and of such length as during the deployment a stop (15) on the rear of the central upright is retained when it bends; it is then pushed back during the withdrawal. Making compensating spring, it reduces the effort to raise. Braking the opening, it avoids at the same time any risk of pinching, the whole moving only on request, without self-drive. The tension can then be adjusted so that the steps do not go by themselves to the horizontal position. They remain in a "broken" position, Figure 6, which is a position from which it is always easy to fold up by a slight push of the hand, even of the tip of the foot, from the bottom as from the top - the fixed lion being (16) -, on the mobile stringer (17), or, on the floor, on its extension (18) or on the post (19) which optionally supports a ramp and a bearing railing in two flaps folding along the ramp. The staircase is in service in this position since, supported by the user, the steps pass horizontally but they return to the "broken" position as soon as he leaves it.

 Another improvement then consists in easily obtaining a stable position, steps horizontal. Note that at the end of the opening stroke, Figure 7, on a small angular clearance, the staircase is temporarily wider by a few millimeters (diagonal of the bars which are at an angle and no longer length). It is therefore sufficient to place an elastic stop, preferably a spring (20) with a short flexible arm (two arms if possible, on a pivot) and with suitable return torque, possibly fixed on the slide (21), in a location such that 'it lightly presses on the fitting (18) of the movable stringer in the "broken steps" position. Under the push of the foot this spring is crushed, the steps passing horizontally.

They stay there because (20) then retaining (18) does not allow the staircase to widen even slightly to allow the biased return of the bars.

Only, from the top, a slight opening impulse on (19) or from the bottom on (17) allows, by compressing (20), to return to the "broken steps" position which then allows the fold by simple push. -In the absence of this spring (20) and with a lower tension of (14) letting the steps come to the horizontal, the fall would be possible from the bottom by preceding the push on the stringer of a traction of the amount central initiating the "break" but, from the top, it would be difficult to reach this central amount.

Another improvement makes it possible to overcome a difficulty specific to the principle of withdrawal: if the upper step were articulated like the others, the central upright would abut at the bottom of the hopper and could not go back up. We know that this step can be a simple board (22), resting on the top of stringers when opening and which is lifted by the top of the central upright during closing. It is interesting to fix it by two hinges, one (23) on the fixing leg of the fixed stringer and the other (24) on the chevetor or at the end of the sliding guide. This step raised by the front during closing will therefore pivot on the rear. The hinges can be swapped, the staircase can therefore be placed to slide on the right as on the left.

 The improvement according to the invention simplifies the manufacture of this laterally retractable staircase. Facilitating its instantaneous and effortless maneuvering, from top to bottom, it will make its specific qualities of space saving and total availability even more attractive.

Claims (5)

REVEDICATIOS 1) Laterally retractable staircases which include half-steps, each in several bars (6), generally two, pivoting on a central upright which is raised and on "U" stringers, the effort to raise being reduced by an arm flexible (14) which acts as a compensating spring and which also brakes on opening, the thrust being exerted by the axes (7) of articulations near the stringers which penetrate into holes (8) formed inside the banks (2) well dimensioned, connected by a thin veil (1), of these "U", retractable stairs laterally characterized in that the thrust is exerted in the same way by axes (7), near the central upright, which penetrate into bores made in the banks (12) and (13) of this amount and seemingly connected. 2) laterally retractable stairs according to claim 1 characterized in that parts (3) and (4) are plates fixed at the ends of bars, each with a winding over its entire depth forming a knuckle which will receive the axes (7) on which they will turn, knuckle at the top of the room near the stringers and below near the central upright. 3) laterally retractable stairs according to claims 1 and 2 characterized in that the axes (7) are supported by the head in the holes provided in the wing, positioned equidistant from the banks of the stringers and the central upright, angles (9) placed on the sails (1) and (li). 4) laterally retractable stairs according to claim 3 characterized in that the holes in the angles of the angles are open to form notches (10) in which the axes (7) are engaged before pushing them back. 5) laterally retractable stairs according to claim 1 characterized in that the flexible arm (14) retaining the opening in the staircase position broken steps ", a short flexible arm (20) is crushed for the passage of the steps horizontally under the push of the foot but then prevents the return by the pressure it exerts on the fitting (18), this return being possible only by exerting a weak impulse, below, on the movable stringer (17) or, above, on the post (19).