US1883777A - Concealed stairway - Google Patents

Description

Oct. 18, 1932. B. FRAZIER CONCEALED STAIRWAY Filed June 17. 1929 2 Sheets-Sheet INVENTOR B Ber? Frazzer Oct. 18, 1932. B. FRAZIER 1,833,777

I CONCEALED STAIRWAY Filed June 17. 1929 2 Sheets-Sheet 2 W 9 4a 55 B4 57 5a 9 j m INVENTOR Bari F'razl'er Patented Oct. 18, 1932 BERT FRAZIER, OF PITTSBURGH, PENNSYLVANIA CONCEALED STAIRWAY Application filed June 17,

My invention relates to a concealed stairway mounted on a swinging trap door in a ceiling, and it has specific relation to an improvement in the concealed stairway of my Patent No. 1,633,321, ,granted'June 21, 1927,

in a new design which lends itself admirably to quantity production, which operates better than the old design, and which embodies certain new parts as follows. 7 m One of the most important innovations embodied in thenew design is a gravity-actuated latch, which is absolutely certain in its 7 operation, and which is so arranged as to be i gripped with the rung member which is used for drawing down the stair from its concealed position. 1

A special form of stay hinge' is provided for preventing excessive downward swinging of the door before the stair is pulled out.

An ofiset stop arm is, provided, for limiting the downward sliding of the'stair.

A new hinge is provided forthe door.

The foregoing and other features are embodied in the new design, which will now be more fully described, reference being had to the accompanying drawings, wherein Fig. 1 is a plan View of the entire equipment, shown with the stair in its, concealed position;

Fig. 2 is a longitudinal sectional view of the same, the section plane being indicated by the broken line IIIIin Fig. l;

Fig. 3 is .a transverse sectional View of the stair, on a scale twice as large as Figs. 1 and 2, the section plane being so chosen as to show the offset stop arm, and being indicated by the line IIIIII in Figs. 1 and 2;

Fig. d is a detail sectional view through one side of the jamb, on a scale four times as large as Figs. 1 and 2, the section plane being so chosen as to show the fastening of the stay hinge, and being indicated by the line IVIV in Fig. 2;

I Figs. 5 and 6 are plan and side views, respectively, of the gravity-actuated latch detached from the stair, on a stilllarger scale;

Figs. 7 and 8 are plan and side views, respectively, of the door alone, on an intermediate scale, partly broken away; and

Figs. 9 and 10 are large-scale plan and side 1929. Serial No. 371,313.

views, respectively, of the door-end of the stay hinge, detached and shown in its maximum extended position.

The invention has reference to a stair 11 comprising two stringers 12 and 12 twelve treads 13,'and a top 14. The treads are securely mortised into the stringers and pro .ject out slightly over the front surfaces of the stringers, but the ends of the treads, where they are mortised into the stringers, '00 are cut back, as indicated at 15, so that they will not interfere with the rollers subsequently described.

The stair 11 is carried by a door 18 comprising two stiles 19 and 19*, two end rails 20? and 20 and a panel 21, as shown in Figs.

7 and 8. The connection between the door and the stair is efiectedby means of two pairs of roller-brackets 22 22 and 23?, 23 each bracket carrying two one-inch rollers 24 with their centers spaced 5 3/64, which'is just enough to permit the rollers to run smoothly over the top and bottom surfaces of the fourinch stringers of the stairs. The rollers are provided with a beveled flange 25. at one end, and the rollers are so mounted that these flanges are on the outside,s0 as to restrict the side play of the stairs. The back or upper roller-brackets 22 and 22 are taller than the lower brackets 23 and 23*. In a preferred embodiment ofiny invention, the

rollers of the upper brackets 22 and 22 are 1% inches further away from the doorthan the rollers of the lower brackets'23 and 23", the brackets being 21% inches apart, from centerline to centerline, measured lengthwise of the door.

' i The door 18 is carried by a'jamb 28 comprising two side members 29" and 29 andv two end members 30 and 30*, joined together to form an oblongbo X-like construction, open at the top and bottom. The jamb has a narrow fillet 31 flush with its top surface, abutting the end 30. 'The jamb sides 29 and 29 carry hinge socket plates 33 95 under the forward edge of the fillet 31, and the door stiles 19 and 19 carry cooperating hinge brackets 35 having laterally extending hinge pintles 37 which. are fitted into the sockets of the jamb hinge plates 33 when the jamb is assembled about the door. The cen ters of the hinge pintles 37 come about flush with the under surface of the door 18. The door, when closed, swings up against a door stop 39 nailed to the jamb sides 29 and 29 and to the jamb end 30.

It will be understood that the jamb is intended to be supported by the joists (not shown) supporting the floor of an attic, and that the door swings down from the ceiling of the room below, being pulled down by means of a cord 40, shown in Fig. 2. When the door is in its closed position, the. stair extends out over the attic floor, in the position indicated in Fig. 2. When the door is swung down to its open position, as indicated in dotted lines in Fig. 8, the stair may be slid down, through the rollers, until its lower end rests on the floor.

The stair is retained in its nested, or upper, position, as shown in Fig. 2, by means of a very special gravity-actuated latch 41, car ried by the stringer member 12 near its lower or front end, and engaging the up bent end of a stop plate 42 on the door-stile 19 The latch 41, as shown in detail in Figs. 5 and 6, comprises a plate 43, to which is hinged one end of a gravity-actuated pawl or detent 44 having a notched forward end 45 for engaging the stop plate 42 on the door. The pawl 44 is prevented from dropping down so far that its notched front end 45 will not properly engage the stop plate 42 by means of a cut 46 and a laterally bent lip 47, on its under surface, to engage against the supporting plate 43 of the latch, as shown in Figs. 5 and 6.

An important feature of the latch 41 is the manner in which it cooperates with a rung or rod 48, extending across the bottom end of the stair, which is grasped by the operator when the stair is to be pulled down to cause it to slide through its rollers on the door.

The latch pawl 44 is disposed under this rung or rod 48, and is provided with a laterally extending pin 49 which is spaced slightly from the rod 48, so that when the latter is grasped by the operator, the pin 49 is also gripped and squeezed uptoward the rod 48,

thereby raising the pawl 44 and disengaging it from the stop plate 42 on the door. It will be noted that the entire operation of the latch 41 is accomplished without any springs or other parts to get out of order.

When the stair is latched in its upper position, its overhanging top end is so nicely counterbalanced, against its bottom end and the weight of the door, that the center of gravity of the whole is above, and to the rear of, the hinge 33, 37 when the door is up or closed, whereas it is above, and in front of, the hinge 33, 37 when the door is swung down or open. Consequently, the door will stay closed, by gravity, when it is up or closed, and it will stay open, bygravity,

when it is down or fully opened, so that a slight touch starting the door away from either position will cause it to continue to swing until it reaches the other extreme position of its movement. This feature avoids the necessity for latches to hold the door closed, it prevents accidents due to the failure of the latch or spring or other means used previous to my invention, as described in the aforesaid patent, and it avoids accidents due to a sudden dropping of the door when the operator starts to open it. Since the door remains, by gravity, in its open position, the operator does not need to hold it open, with one hand, while releasing the stair so as to permit it to slide down, with the other hand.

The downward sliding movement of the stair is limited by a stop arm 51 mounted on the stringer 12 under the fifth tread from the top, and having a downwardly extending arm which is laterally offset, as indicated at 53, for engagingthe stop plate 42 on the door, or other equivalent device, when the stair is fully down. The offset is needed in order to clear the nuts on theends of the rollers which engage the under surface of the stringer.

Another new feature introduced by my present invention is a special form of stay hinge 55 which prevents excessive opening of the door and yet permits the door to be closed without requiring the operator to do anything first to the stay hinge. The mounting of this stav hinge requires a special hinge bracket as subsequently described.

The stay hinge comprises a short arm 57, which is hinged to the top of the doorstile 19 by means of a. bracket 58, and a long arm 59, about three times as long as the short arm 57. The long arm 59 is hinged to the side 29 of the iamb by means of a special bracket 60' which is screwed to the iamb at one end and is offset at the other end, in order to clear the door stop 39 and to provide an inexpensive and. reliable pivot 61 for the end of the stay hinge, at point above the door18.

The two arms 57 and 59 of the stay hinge 55 are pivoted together at 62, as indicated in Figs. 7 to 10; and one of the arms, for example the arm 57, is provided with a bentover lip 63 for engagi the top of the other arm, so as to limit the opening of the stay hinge to an angle somewhat less than 180. so that the arms will readily fold up again when the door is closed. V

The entire construction of the concealed stairway is simplicity in the extreme, and it is neat, sturdy, absolutely fool-proof, contains no parts to get out O'ii order, and is worked out so that its constituent parts are inexpensive to manufacture and assemble.

I claim as my invention:

1. In combination, a. hinged trap door, a stair slidably supported thereon in such man ner that it may be moved up into the space above the trap door orslid down to a floor below, characterized by having a handle-rung extending across the stair near the bottom end thereof, a stop member on the u per surface of the trap door near the bottom end to in such spaced position relative thereto as to be readily grasped by the hand of the open ator and squeezed up against said handlerung to release said latch when the stair is to be lowered.

2. In combination, a hinged trap door, a stair slidably supported thereon in such manner that it may be moved up into the space above the trap door or slid down to a floor below, characterized by-having ahandle-rung extending across the stair near the bottom end thereof, a stop member on the upper surface of the trap door near the bottom end of the latter, and a gravity-actuated hinged latch having a limited swinging movement in a vertical plane about apivot secured to the inner face of one of the stringers of the stair and having an inclined latch-end engageable with said stop member, and means operable from said handle-rung for releasing said latch from said stop-member.

3. In combination, a hinged trap door, a jamb therefor, a stair slidably supported thereon in such manner that it may be moved up into the space above the trap door or slid down to a floor below, and a folding stay hinge between said door and said jamb, characterized by the fact that said folding stay hinge comprises hinged arms limited to an open position in which the arms have an angle somewhat less than 180 betweenthem, so that the arms will readily fold up again when the door is closed, and characterized further by.

the fact that one arm of said stay hinge is secured to the upper surface of the door by means of a hinge bracket spaced from the hinged end of the door, and by the fact that another arm of said stay hinge is secured to a side member of said amb by means of an offset hinge bracket having its hinge end spaced from the jamb and extending above the door when the latter is in its upper or closed position, said ofl'set hinge bracket having a lower vertical portion secured to the 1 side of said side member of the jamb, an intermediate horizontal portion extending sub stan'tially against the top of the door when the latter is closed, and an upper vertical portion hingedly carrying one end of the arm of the stay hinge.

4. In combination, a hinged trap door, a

stair, means comprising rollers engaging under the stringers of the stair, for slidably supporting the stair on said trap door in such manner that it may be moved up into the space above the trap dooror slid down to a floor below, said stair being more than twice as long as said door, a stop member on the upper surface of the trap door near the bottom end of the latter, and a stop arm secured to the inner side of one of the stair stringers above the center thereof and having a'depending end offset to clear said rollers and adapted to engage said stop member tolimit the downward sliding movement of the stair relative to the trap door.

5. In combination, a trap door, a jamb therefor, hinges between the sides of the trap I door, near one end thereof, and the sides of the jamb, each hinge comprising a part mounted on the door and a part mount ed on the jamb, one of said parts being a. hinge socket member and the other being a hinge pintle member, whereby,when the jamb is assembled and secured together around the door, the latter is held in place therein and is carried thereby, and a stair slidably supported by the trap door above the upper surface thereof in such manner that it maybe pushed up into the space above the trap door or slid down to the floor below,

the position of the hinges being such that the center of gravity of the combined door and stair, with the stair in the pushed-up position shifts from one side, to the other, of a vertical line above the hinges, as the trap door is swung from its upper closed position to its lower open position, so that the trap door automatically remains, by gravity, in either one of said positions.

6. In combination, a trap door, a jamb therefor, hinges between the sides of the trap door, near one end thereof, and the sides of the jamb, each hinge comprising a part mounted on the door and a part mounted on the jamb, one of said parts being a hinge socket member and the other being a hinge pintle member, whereby, when the jamb is assembled and secured together around the door, the latter is held in place therein and 1s carried thereby, and a stair slidably supof gravity of the combined door and stair,

with the stair in the" pushed-up position, shifts from one side, to the other, of a vertical line above the hinges, asthe trap door is swung from its upper closed position to its lower open position, so that the trap door 7 automatically remains, by gravity, in either one of said positions, the hinge socket and pintie being below the centerline of the side profile of the door, so as to increase the forward shift of the center of gravity when the 7 door is swung down.

In testimony whereof, I have hereunto subscribed my name this 12th day of June, 1929.

BERT FRAZIER.

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