Title:
Swivel mechanism for seats
United States Patent 2351194


Abstract:
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...



Inventors:
Carrington, Herman
Application Number:
US39627041A
Publication Date:
06/13/1944
Filing Date:
06/02/1941
Assignee:
Flossie, Shadden P.
Shirley, Anne Davies
Primary Class:
Other Classes:
248/162.1
International Classes:
A47C3/18
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Description:

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 normrally 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 inven- "20 tion, 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 invention resides more particularly in the particular construction for limiting or impeding the vertical movement resulting from the cam action. Thus an important feature of the present invention resides in a construction whereby the resistance to vertical movement is increased when the movement exceeds a predetermined value, so that the resistance to rotation is greatly increased after the seat has been rotated through a predetermined angle. The parts may be so proportioned that the seat rotates with relatively slight resistance 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 without excessive shock and noise.

In the drawings: Fig. 1 is an elevation view showing two swivel seats positioned in front of a counter, the seats incorporating the swivel mechanism of the invention; Fig. 2 is a vertical section through one swivel mechanism, in accordance with the invention; Fig. 3 is a perspective view of the two cam elements eniployed in the construction of Fig. 2; 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. 2, 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 900 from Fig. 7, illustrating the cam construction and illustrating the cams as separated.

Referring first to Pig. 1, the usual swivel seat assembly includes as its essential elements a seat I 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 900 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 extending spindle 6, and may be locked thereto by a setscrew 7. 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 fit, and has an outwardly extending flange 10 at its top, which flange rests on a shoulder I in the pedestal 2. Sleeve 8 is locked against rotation or accidental removal by a setscrew 12.

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 13 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 14 at the lower end of the large bore 13 in the sleeve through a pair of helical compression springs 15 and 16 which surround the spindle 6. The lower spring 16 is relatively heavy and stiff, as compared to the upper spring 15. A freely floating washer It separates the two springs. A plurality of thrust washers 18 are provided between the upper end of the top spring 15 and the lower end of the hub 9, these washers reducing the friction to rotation between the hub 9 and the spring 15. Furthermore, the height of the seat may be varied as desired by increasing or decreasing the number of the washers 18.

When the seat is unoccupied, upward movement of the seat and the spindle 6 by the springs and 16 is limited by engagement of a cam 19 (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 19 has a pair of cam faces 21 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 21.

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 21; 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 15 and 16 causes the seat, spindle and the cam member 19 to rotate as a unit until both of the cam faces 21 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. 1.

If the seat is forcibly turned when not being occupied, one of the faces 21 and one of the faces 23 on cam 19 is slid in a helical path along one of the faces 24 and one of the faces 26, respectively, thereby lowering the spindle 6 and the hub 9, together with the seat, and compressing the light spring 15. The spring 16 is also compressed to a limited extent, but it is so much stiffer than the spring 15 that its deflection is negligible until the spring 15 has been fully compressed. When the seat is released, the reaction of the spring 15 is sufficient to raise the cam 19, 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 15 is compressed, the faces 21 and 23 move along the cooperating cam faces 24 and 26, and the resistance to rotation is relatively small. However, if attempt is made to rotate the seat beyond its intended angle of easy rotation, the spring 15 becomes fully compressed and one of the relatively steep cam faces 22 abuts its cooperating steep cam surface 25. Because of the relatively great stiffness of the spring 16 and the greater inclination of the cam faces 22 and 25, the resistance to further rotation is greatly increased, and can be made as great as may be necessary, by making the cam faces 22 and 25 sufficiently steep, and making the spring 16 sufficiently stiff.

However, because of the fact that the seat is still able to rotate, although with increased resistance, after the spring 15 has been fully compressed 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.

When the seat is occupied, the weight of the occupant is sufficient to fully compress the spring 15 and slightly compress the stiff spring 16. This separates the cam faces 21 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 18. 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 19, which downward movement is now resisted by the stiff spring 16, 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 15 and 16 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 16 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 19a is uniform for all angular movement.

The bore in the pedestal 2 which receives the cam 19 and the sleeve 8, is preferably closed at the lower end, as shown in Fig. 2, and filled with oil to a point adjacent the setscrew 12, or slightly 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 30 where it strikes the spring 15 or the spindle 6, and splashes up onto the washers 18 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 other than the specific structure shown in Fig. 2. Two alternative constructions are shown in Figs. 5 and 6.

In Fig. 5 the pedestal 2b supports a sleeve 8b 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 9b, 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 15b and 16b, respectively, which are compressed between the lower end of the sleeve 8b and a collar 31 on the lower end of the spindle 6b. A thrust washer 32 may be provided between the upper end of the light spring 15b and the lower end of the sleeve 8b. A separating washer corresponding to the washer 17 of Fig. 2 might also be employed between the springs 15b and 16b of Fig. 5, but there is shown in Fig. 70 5 an alternative construction which includes a sleeve 33 interposed between the spindle 6b and the light spring 15b and having a flange 34 on its lower end extending outwardly between the two springs. The length of the sleeve 33 is such that its upper end abuts against the washer 32 before the spring 15b is fully compressed, so as to prevent possibility of the light spring 15b 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 16b from the stationary sleeve 8b.

The construction shown in Fig. 6 is identical with that shown in Fig. 5, except that the light spring 15b 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 16c 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 15 is made of such thin wire as to make 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 vertical 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 to 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 Sof constant pitch and a second surface of constant 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 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 being interposed between a shoulder carried by the spindle and a shoulder within the column, and said springs being respectively a light spring and ?a 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 arc 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.