US2351194A - Swivel mechanism for seats - Google Patents

Description

June 13, 1944. A. DAVIES 2,351,194

SWIVEL MECHANISM FOR SEATS Filed June 2, 1941 I 2 sheet s sheet l r J v g June 13, 1944. A. E. DAVIES 2,351,194

SWIVEL MECHANISM FOR SEATS Filed June 2, 1941 2 Sheets-Sheet 2 mined angle,

1 vention;

Patented June 13, 1944 UNITED STATES PATENT OFFICE SWIVEL MECHANISM FOR SEATS Arthur E. Davies, deceased, late of Los Angeles, Calif., by Carrington Herman, administrator, Los Angeles, Calif assignor of twenty percent to Flossie P. Shadden, Los Angeles, Calif, and eighty percent to Shirley Anne Davies Application June 2, 1941, Serial No. 396,270

4 Claims. (01'. 155-95) This invention relates to swivel seats and particularly to seats of the self-restoring type which, when rotated out of a normal position and released, automatically return to normal position.

Thus in swivel seats employed at lunch counters,

and the like, it is desirable that the seats be normally positioned directly facing the counter, but

be capable of being turned, when in use, at the convenience of the occupant.

An object of the invention is to provide a simple and inexpensive, self-restoring, swivel mechanism that is durable and reliable in use.

Another object is to provide a particularly simple and rugged swivel mechanism that limits the extent of rotation of the seat wtihout excessive noise or shock.

Other more specific objects and features of the invention will become apparent from the following description, with reference to the drawings,

of certain particular embodiments of the invention, as disclosed in the drawings.

Basically, the construction in accordance with the present invention comprises a rotatably supported spindle on which the seat is supported, with cooperating cam means on the spindle and on the stationary supporting structure therefor, for transferring rotary movement of the spindle into vertical movement which is resisted either by gravity or by spring force. Such construction,

however, is broadly old, and the present invensistance through its normal arc of movement but with substantially increased resistance beyond the normal arc of movement, thereby providing a cushion stop. mechanism which limits rotation seats positioned in front of a counter, the seats incorporating the swivel mechanism of the in- Fig. 2 is a verticalsection through one swivel mechanism, in accordance with the invention;

f Fig. 3 is a perspective view of the two cam ele- 'riients' employed intheconstruction of Fig. 2;

The parts may be so proportioned that the seat rotates with relatively slight re- Fig. 4 is a perspective view, similar to Fig. 3, but showing a modified cam construction;

Fig. 5 is a vertical sectional view, similar to Fig. but showing an alternative construction; and

Fig. 6 is a vertical sectional view, similar to Fig. 5, but showing still another alternative construction.

Fig. '7 is a fragmental side elevation illustrating the cam formation.

Fig. 8 is a fragmental side elevation taken at approximately from Fig. '7, illustrating the cam construction and illustrating the cams as separated.

Referring first to Fig. 1, the usual swivel seat assembly includes as its essential elements a seat l and pedestal 2, the latter being anchored to the floor, platform, or other supporting surface 3. Fig. 1 also shows a counter 4 with which the seats are associated and shows the two seats A and B in two different positions of adjustment, the seat A facing the counter in normal position and the seat B being swung substantially 90 from normal position. As will appear later, the seat B will not remain in the position shown when released, but will return to the same position as seat A.

The seat I is supported on and rigidly secured to a seat frame 5. Referring to Fig. 2, the seat frame 5 is secured to a downwardly extendin spindle 6, and may be locked thereto by a setscrew i. The spindle depends downwardly into the pedestal 2, which is hollow and contains a stationary sleeve member 8, which rotatably guides and supports the spindle 6 and a hub 9 on the seat frame 5.

The sleeve 8 may be fitted in the pedestal 2 with an easy, sliding lit, and has an outwardly extending flange Ill at its top, which flange rests on a shoulder l l in the pedestal 2. Sleeve 8 is locked against rotation or accidental removal by a setscrew' l2.

Near its lower end, the sleeve 8 has a relatively small bore dimensioned to just slidably receive the spindle 6 and guide the latter for rotary and vertical movement. However, the upper part of the sleeve 8 contains a larger bore l3 of substantially larger diameter than the spindle 6 and substantially the diameter of the hub 9, so that it has a guiding action on the latter.

The weight of the seat is normally transferred to a shoulder It at the lower end of the large bore I3 in the sleeve through a pair of helical compression springs l5 and I6 which surround the spindle 6; The lower spring I6 is relatively heavy and stiff, as compared to the upper spring I5. A freely floating washer I'I separates the two springs. A plurality of thrust washers I8 are provided between the upper end of the top spring I5 and the lower end of the hub 9, these washers reducing the friction to rotation between the hub 9 and the spring I5. Furthermore, the height of the seat may be varied as desired by increasing or decreasing the number of the washers I8.

When the seat is unoccupied, upward movement of the seat and the spindle 6 by the springs I5 and I6 is limited by engagement of a cam I9 (which is secured to the lower end of the spindle 6 by a pin 20) against a cam face on the lower end of the sleeve 8. As shown in Fig. 2 and Fig. 3 the cam I9 has a pair of cam faces 2I of relatively low slope, which merge at their upper ends into the lower ends of faces 22 of relatively steep slope, the latter in turn merging at their upper ends into a third pair of faces 23 which are of substantially the same slope as the faces 2|. The cam face on the lower end of the sleeve 8 has a pair of lower faces 24 of the same slope as the faces 2| a pair of intermediate faces 25 of the same slope as the faces 22, and a pair of upper faces 26 of the same slope as the faces 23.

When the seat is unoccupied, the force of the springs I5 and I6 causes the seat, spindle and the cam member I9 to rotate as a unit until both of the cam faces 2i contact the cam faces 24, and both of the cam faces 26 contact the cam faces 23. In this position the seat faces in the desired direction and is in its uppermost position, This is the position of the seat A in Fig. l.

If the seat is forcibly turned when not being occupied, one of the faces 2I and one of the faces 23 on cam I9 is slid in a helical path along one of the faces and one of the faces 26, re-

spectively, thereby lowering the spindle 6 and the hub {together with the seat, and compressing the light spring I5. The spring I6 is also compressed to a limited extent, but it is so much stiffer than the spring I5 that its deflection is negligible until the spring I5 has been fully compressed. When the seat is released, the reaction of the spring I5 is sufiicient to raise the cam I9, causing it to slide with respect to the cam faces on the sleeve 8, and restore the seat to its normal position.

If the seat is deflected through only a relatively small angle, only the light spring I5 is compressed, the faces 2! and 23 move along the cooperating cam faces 24 and 26, and the resistance to rotation is relativelysmall. However, if

attempt is'made to rotate the seat beyond its intended angle of easy rotation, the spring I5 becomes fully compressed and one of the relatively .by making the cam faces 22 and 25 sufllciently steep, and making the spring I6 sufficiently stiff.

However, because of the fact that the seat is still able to rotate, although with increased resistance, after the spring I5 has been fully coinpressed and the cam faces 22 and 25 have contacted, there is no violent impact or shock when the seat is rotated beyond the arc of normal easy swinging movement. 7

When the seat is occupied, the weight of the occupant is sufficient to fully compress the spring I5 and slightly compress the stiff spring I6. This separates the .cam faces 2I and 23 from the cam faces 24 and 26, respectively, so that the cams do not resist rotation, within limits, and. the occupant can swing the seat back and forth, the hub 9 (Fig. 2) rotating on the washers I8. However, if the occupant attempts to swing the seat beyond'its intended range of free movement, one of the cam faces 22 abuts against its cooperating cam face 25 so that further rotation is impossible without further downward movement of the cam I9, which downward movement is now resisted by the stiff spring I6, and the latter limits the additional rotation to a very small angle.

If the occupant leaves the seat while it is rotated out of normal position, the springs I5 and I6 immediately bring the cam faces together and cause them to function to restore the seat back to normal position.

As will be obvious, both the stiff spring I6 and the steep cam faces 22 and 25, function to increase the resistance to rotation as the seat is swung beyond the predetermined point and either of these features may be used alone, without the other. Thus, if desired, the simple cam structure shown in Fig. 4 may be employed instead of the complex cam structure of Fig. 3. The cam faces of Fig. 4 are of uniform slope throughout so that the extent of vertical movement in response to rotation of the cam I 9a is uniform for all angular movement.

The bore in the pedestal 2 which receives the cam I9 and the sleeve 8, is preferably closed at the lower end, as shown in Fig. 2, and filled with oil to a pointadjacent the setscrew I2, or sl ghtly therebelow when the seat is in uppermost idle position. Thus the cam surfaces are constantly immersed in oil. Furthermore when the spindle 6 is depressed, it displaces an additional amount of oil, which oil is forced up through a vertical groove 29 in the exterior surface of the sleeve 8 and through a hole 35 where it strikes the spring I5 or the spindle 6, and splashes up onto the washers I8 to lubricate them.

The principle of employing a cam to transfer rotary motion of a seat spindle into vertical motion and then providing a structure for offering increased resistance to vertical motion after predetermined movement, can be employed in various structures otherthan the specific structure shown in Fig. 2. Two alternative constructions are shown in Figs. 5 and 6.

In Fig. 5 the pedestal 22) supports a sleeve 81) through which the spindle 6b extends, as in Fig. 1, but the cam faces are formed on the upper end of the sleeve 8b and the lower end of the hub 91), respectively, so that in response to rotation of the seat the cam faces elevate the spindle instead of depressing it. Such elevation of the spindle is resisted by gravity and also by a pair of helical springs I5b and IE1), respectively, which are compressed between the lower end of the leeve 8b and a collar 3| on the lower end of the spindle 6b. A thrust washer 32 may be providedbetween the upper end of the light spring I52) and I6b of Fig. 5,'but there is shown in Fig.

5 an alternative construction which includes a sleeve 33 interposed between the spindle Bb-and the light spring I51) and having a flange 34 on its 'lower end extending outwardly between the two springs. The lengthof the sleeve 33 is such that its upper end abuts'agains t the washer 32 before the spring 15b is fully compressed, so as to prevent possibility of the light spring Ib buckling. Of course, after the upper end of the sleeve 33 contacts the washer 32, force is transmitted directly through the sleeve 33 to the spring l6b from the stationary sleeve 81).

The construction shown in Fig. 6 is identical with that shown in Fig. 5, except that the light spring b and the sleeve 33 have been eliminated. With this construction vertical movement of the seat in response to initial rotation is resisted only by the weight of the seat assembly. However, after the seat has swung through a predetermined angle, the heavy spring l6c is compressed to offer greatly increased resistance to further rotation.

It is to be understood that the sleeve 33 having the flange 34 thereon, as shown in Fig. 5, is also adaptable for use in the assembly of Fig. 2, and

should be used in Fig. 2 if the light spring [5 is made of such thin wire as to mak buckling of the spring possible.

Various departures from the exact constructions shown in the various embodiments illustrated may be made without departing from the invention, and the latter is, therefore, to be limited only to the extent set forth in the appended claims.

What is claimed is:

1. A swivel seat construction comprising; a

supporting column, a seat having a spindle extending into and guidingly supported by said column for vertical and rotary motion, cooperating cam members on said spindle and column, respectively, for moving said spindle vertically in response to rotation thereof out of a predetermined neutral position, each cam member having a first cam surface of relatively low, constant pitch and a second cam surface of constant pitch steeper than the pitch of said first cam surface, said first cam surfaces on said two respective cam members engaging with each other over a substantial surface area during a first range of rotation of said seat from said neutral position and said second cam surfaces of said respective cam members engaging with each other over a substantial area during rotation of said spindle beyond said first range, and means for yieldably resisting said vertica1 movement of said spindle away from said neutral position.

2. A swivel seat construction comprising: a pedestal having a vertical cylindrical bearing means therein, a seat assembly comprising a journal member journaled in said bearing means for vertical and, rotary movement therein, a cam mechanism for vertically moving said journal member with respect to said pedestal in response to rotation therebetween, said cam mechanism comprising a first cam means connected to said pedestal and a second cam means connected to said journal member and slidable with respect of constant pitch and a second surface of conto said first cam in response to rotation of said journal member with respect to said pedestal, each of said cam means having a first surface stant pitch greater than the pitch of said first surface, the said first surface on one of said cam means being longer than the cooperating said first surface on the other cam means, whereby rotation of said journal member with respect to said pedestal through an initial range slides said one first cam surface along the other said first cam surface while making contact therewith over the entire area of the said other cam surface until said second cam surface on said second cam r means contacts said second cam surface on said first cam means and further rotation causes said second cam surface on said second-cam means to slide along the second cam surface on said first cam means and carry said first cam surfaces apart.

3. In a swivel seat, a supporting column, a seat having a spindle extending into and guidingly supported in said column for vertical and rotary motion, cooperating cams on said spindle and column, said cams having cooperating cam faces inclined from the axis of the spindle at an acute angle, a pair of helical compression springs mounted on the spindle within the column one above the other and between which there is positioned a washer member whereby said springs may have relative rotation, said springs bein interposed between a shoulder carried by the spindle and a shoulder within the column, and said springs being respectively a light spring and a relatively stiff spring, whereby a light load supported upon the seat will compress the light spring to move the cooperating cam surfaces out of engagement, permitting relative rotation of the seat and spindle through an are limited by said cooperating cam faces, whereafter a heavier load support upon said seat will act in addition to compress said stiffer spring, whereafter a further separation of the cooperating cam surfaces may be effected, permitting relative rotation of the seat and column, which rotation however is still limited by the contacting of the said acutely inclined cooperating cam faces, and whereafter, upon the removal from the seat of said loads, the cam surfaces will cooperate to return the seat to a predetermined position.

4. The combination as defined in claim 3 in which the cooperating cams are cylindrical cams, the cam faces of which are complementary and include initial cooperating surfaces extending at acute angles relative to the axis of the spindle which terminate in elongated cooperating faces of greater angle of inclination than said initial cooperating faces.

CARRINGTON HERMAN, Administrator of the Estate of Arthur E. Davies,

Deceased.

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