US2596424A - Folding chair - Google Patents

Description

May 13,1952 6. B. MORSE FOLDING CHAIR Filed Aug. 29, 1949 llll H 1",,

Patented May 13, 1952 FOLDING CHAIR Glenn B. Morse, Grand Rapids, Mich., assignor to Ionia. Manufacturing Company, Ionia, Mich., a

corporation of Michigan Application August 29, 1949, Serial No. 112,850

9 Claims. 1

This invention provides a folding chair mechanism in which the seat and legs move with respect to each other during the folding operation without the assistance of links or other moving parts. In the erected position, the chair stands rigidly regardless of the point on the seat at which load is applied. In the folded position, there are no auxiliary protruding members to interfere with the stacking characteristics of a series of such chairs. The design and construction is best adaptable to the use of sheet metal; and in the preferred form of the invention, provides an arrangement which is exceptionally easy to assemble during the manufacturing operation.

In the preferred form of the invention a pair of structurally associated and parallel front legs is pivotally connected with a seat member on an aXis parallel to the width of the chair. Near the rear portion of this seat member, back legs are also pivotally connected and suitable structure is preferably provided causing the back legs to move about their axis of rotation together. The support of the chair in the erected position is completed by an abutting relationship established between the uppermost portion of the rear legs and the front legs which provides bearing engagement and also provides for limiting the axial movement of the rear legs with respect to the front legs. To facilitate the erection of the chair, the rear leg is maintained in sliding engagement with the front leg system to avoid the necessity of inserting the rear leg into the receiving means provided by the front leg structure each time the chair is unfolded. The sliding arrangement provides for axial movement of the rear leg with respectto the front leg, and the pivotal arrangement between the seat member and the front and rear leg systems causes a definite pattern of movement of the legs and seat as the chair is erected. As the seat is rotated to the horizontal position, the upper portion of the rear leg moves along the slot and gradually forms the angle characteristic of the erected chair. As the complete angle is assumed, abutment means on the front leg prevents further movement of the rear leg and the firm abutting relationship characteristic of the present invention is automatically established thereby. While there are a variety of ways in which the sliding relationship of the rear and front legs can be provided, the preferred form of the invention comprises a sheet metal structure of the front legs joined at the rear portion thereof, and providing a slot in which an extension of the rear leg protrudes. This engagement of projection and slot establishes the sliding relationship desired, and the characteristic shape of the projection to be discussed later herein aids in guiding the rear and front legs into firm abutting relationship. Means are also provided preventing the inadvertent withdrawal of the front leg from sliding engagement with the rear leg, the preferred form of such means comprising a bent ear on the projection of the rear leg which remains inside the hollow front leg structure. Assembly of the device in the first instance is provided either by an access tab left open during the fabrication of the closed front leg structure (in which case the rear leg is inserted and the said tab then turned down) or the front leg structure may be left open sufficient to admit the projection on the rear leg and then pressed to the fully closed position after such assembly has been effected. V

The various features of the present invention will be discussed in detail by an analysis of the accompanying drawings in which:

Figure 1 is a perspective View of a chair embodying the present invention.

Figure 2 is a section showing the relationship of the legs and seat of the chair shown in Figure l in the erected position.

Figure 3 is a view showing the relationship of the front and rear legs with the chair in the folded position.

Figure 4 is a perspective view of a section of the'front leg taken at a point along the slot and showing in dotted lines the position of an access tab provided to admit the retaining member on the rear leg.

Referring to Figure 1 the chair generally designated as Ill is provided with the U-shaped member H. The legs of the U provide the front legs of the chair, while the back portion of the U provides the support for the back panel l2. The legs l3 and I l provided by the member ll are joined near their lower extremity by the cross member [5, and are preferably provided with the rubber feet l6 and I! at the lower extremities.

The seat member I8 i pivotally connected to the legs l3 and hi on the axis l9 which passes transversely with respect to the seat of the chair in the generally central area thereof. At the rear portion of the seat member l8, the rear legs 20 and 2| are pivoted on the axis 22. Preferably, the structure of both the front and rear legs is formed of sheet metal with the seam of the front leg occurring at the rear thereof.

Referring to Figure 2, the arrangement of the axes l9 and 22, and the action of the rear leg at the abutment 23 establish a definite relationship between these members that is not dependent upon the part of the seat at which the load is applied. To aid in the understanding of the geometry of forces involved here, let it be assumed that the legs of the chair are mounted upon casters rather than upon the rubber feet shown in Figure 1. Under these conditions, load applied at the seat of the chair will cause a tendency for the front leg system to rotate in a clockwise direction about the axis l9, and will tend to cause the rear leg 20 to move in a counter-clockwise direction about the axis 22. This will cause a tendency for pressure to be generated between the front and rear legs, since each tends to rotate in the opposite direction about its pivot in the seat member. This opposite rotation is resisted by the engagement of the shoulder portion 25 of the rear leg with the rear-most surface 26 of the front leg. It is also possible to provide this bearing action by permitting the projecting portion 21 to contact the inside of the front of the leg l3. In the preferred form of the invention, however, the projection 21 serves only to engage the abutmeut 23; and the angle of the upper portion of this projection with respect to the front leg causes the legs to becomesecurely held together.

As the chair is folded from the position shown in Figure 2 to that shown in Figure 3, the seat member [8 moves in a clockwise direction about the axis IS with respect to the front leg, causing the axis 22 to move downwardly and draw the projecting portion 21 of the front leg axially along the slot. Immediately as this movement begins, pressure is released from the abutment 23 provided by the end of the slot 24, and a loose sliding engagement is effected between the front and rear legs causing little resistance to the folding movement. During this folding movement, and while the chair is in folded position, the retaining ear 28 prevents the inadvertent removal of the projecting portion 21 from engagement with the slot 24. Preferably the ear 28 is simply formed by a turned-portion of the material of the projected portion 21. The projecting portion, incidentally, is most easily formed simply by compressing a section of the rear leg so that the sheet metal no longer forms a hollow section but simply provides a pair of superimposed layers of metal. The point at which the rear leg changes from a hollow section into the flat section provides the shoulders 25.

The assembly of the chair at the factory involves the insertion of the projecting portion 21 into the confines of the front leg either through an access tab such as in shown at 29 in Figure 4, or through the opening provided by the formation of the front leg with the seam not completely closed. It may be left open sufficiently to admit the retaining ear 28, and then closed into the position shown in Figure 4 after such assembly has been effected. Preferably, the tab 29 is positioned at some place along the slot 24 where the strain and wear is least severe. It

,may be noted in this connection that the angular relation of the rear and front legs, together with the distance between the axes l9 and 22 will determine the length of the slot 2 and its position with respect to the axis I9.

The formation of the slot 2 3 is most easily effected by the provision of a cutaway portion in one side of the sheet metal forming the hollow leg structure. In this manner the abutment portion 23 consists of essentiallysolid material not separated in the middle by a seam. Welding is preferably provided at this juncture, but it is best that the abutment portion be solid andthat welding not be depended upon to maintain the integrity of the abutment against the forces generated.

The particular embodiments of the present invention which have been illustrated in the accompanying drawings and described herein are for illustrative purposes only and are not to be considered as a limitation upon the scope of the appended claims. In these claims it is the in- '4 tent of the inventor to claim the entire invention to which he is entitled in view of the prior art.

I claim:

1. In a folding chair, the combination of the following: means forming a seat; first leg means pivotally connected to said seat adjacent the central portion thereof; second leg means pivotally connected to said seat means adjacent the rear thereof and having an engaging portion; means forming a slot in said first leg means axially disposed with respect thereto and adapted to receive said engaging portion, the upperend of said slot means being positioned to prevent the movement of said engaging portion beyond a point corresponding to the erected position of said chair; means forming a retaining projection on said engaging portion preventing the withdrawal of said engaging portion from said slot means; means associated with said slot means and forming a closable access opening permitting the insertion of said engaging portion and projection in said slot; and means forming a bearing surface associated with said second leg means and disposed to bear against said first leg means.

2. A folding chair comprising a seat, fron legs pivoted at intermediate side portions of said seat, said legs containing axial slots opening rearwardly thereof, rear legs pivoted at rearwardly disposed side portions of said seat, said rear legs having end portions rigid therewith slidably received in said slots, retaining means carried by said end portions preventing their withdrawal from said slots, and bearing surfaces carried by said front and rear legs for engagement when said chair is extended.

3. A folding chair as set forth in claim 2 wherein said end portions are integral with said legs respectively.

4. A folding chair as set forth in claim 2 wherein said end portions and retaining means are integral with said legs respectively.

5. A folding chair as set forth in claim 2 wherein said rear legs provide bearing shoulders adjacent said end portions.

6. A folding chair as set forth in claim 2 wherein said rear legs are reduced to define said end portions.

7. A folding chair as set forth in claim 2' wherein said slots have continuous upper edges.

8. A folding chair as set forth in claim 2 wherein said slots have upper edges providing limiting abutments for said end portions.

9. A folding chair as set forth in claim 2 wherein said end portions are formed with abutments engaging said front legs internally when said chair is extended.

' GLENN B. MORSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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