US3385550A - Memory swivel for swivel chair - Google Patents

Description

May 28, 1968 F. DOERNER MEMORY SWIVEL FOR SWIVEL CHAIR Filed Sept. 28, 1966 l la Ill TL J INVENTOK FMNK DOEMEK ATTORNEY United States Patent 3,385,550 MEMORY SWIVEL FOR SWIVEL CHAIR Frank Doemer, Waterloo, Ontario, Canada, assignor to Doerner Products Co., Limited, Waterloo, Ontario, Canada, a corporation of Canada Filed Sept. 28, 1966, Ser. No. 582,746 1 Claim. (Cl. 248-417) ABSTRACT OF THE DISCLOSURE A memory swivel for a chair having an upper and lower sleeve like cams mounted on the chair spindle, the upper sleeve being fixed against rotation and the lower sleeve secured to the spindle by a pin which extends into an enlarged slot formed in a tubular control member fixed to a support post. The lower sleeve rotates with the spindle with the rotation limited 'by the pin to about 90 in either direction from the centered position. When the spindle is under load the cams are out of contact.

Background of inventiom This invention relates to what is commonly known as a memory swivel for a swivel chair; that is to a swivel which is constructed and arranged so that it will have a centered position and will automatically return to that position whenever the chair is swivelled in either direction from such centered position.

This invention relates to that type of memory swivel which comprises a base member having a tubular fixed post, a chair spindle mounted in said post for rotative movement therein, spring means resiliently supporting said spindle for longitudinal up and down movement, a pair of sleeves mounted on said spindle in end-to-end relationship within said post, one of said sleeves being secured to the post and the other being secured to said spindle, said sleeves having on their contiguous ends, spiral cam faces which are complemental to each other and when brought into engagement by said spring biasing means will react to return the spindle to a predetermined centered position.

When a load is applied to the spindle it moves downwardly separating the two cams which permits the spindle to freely swivel about its longitudinal axis in either direction from the centered position. One of the problems experienced with the type of memory swivel heretofore in use, is that slamming of the cams takes place when the spindle is rotated from the centered position. This results from the fact that the crests of the cams form a stop to limit the swivelling of the spindle in either direction from a centered position. This constant slamming of the cams results in breakage and damage due to the cam pressure.

Description of invention An object of this invention is to provide a member for restricting the rotation of the spindle to less than 90 in either direction from the centered position and thus eliminate the slamming action heretofore present in the memory swivels presently in use.

The present invention is accomplished by a memory swivel for a swivel chair comprising, in combination, a base member having an upright tubular fixed post in which is mounted a tubular control, a chair spindle mounted in said tubular control for rotative and longitudinal movement therein, spring mean resiliently supporting said spindle, upper and lower sleeves mounted in endto-en'd relationship within said tubular cont-r01, the upper sleeve being secured to the tubular control, and a pin extending diametrically through the spindle and the lower sleeve thereby securing it to the spindle to be movable therewith, said sleeves having on their opposed contiguous ends plate cams normally out of engagement when said spindle is under load and cooperating to return said spindle to a centered position when said spindle is not under load and an enlarged slot in the tubular control in registration with lower sleeve an an extension on the pin projecting into the slot, thereby limiting the rot-ative movement of the spindle to about in either direction from the centered position without interferring with the free up and down movement of the spindle and without injurious pressures on the cams.

For an understanding of the invention and its construction and operation reference is to be made to the following description which is illustrated by the accompanying drawings.

In the drawings;

FIGURE 1 illustrates a memory swivel, partly in cross-section, constructed in accordance with the present invention.

'FIGURE 2 is a view, partly in cross-section, with the spindle under load with the cam faces out of contact and the spindle rotated out of its centered position.

.FIGURE 3 is a cross-sectional view on the line 33 of FIGURE 2.

FIGURE 4 is a view, partly in cross-section, of a memory swilvel constructed according to the prior art, .to illustrate the construction heretofore in use.

Referring now to the drawings, I have shown only such parts of the swivel chair as are necessary for the explanation of the present invention.

The swivel chair comprises a base 10, a seat III, a seat support member 12, a tubular post 13, which is secured to and supported by the base in an upright position, a tubular control 14, which fits inside the post 13 with a slide fit and is secured against rotating therein by a pin 15.

The memory swivel of the present invention which is illustrated in FIGURES 1, 2 and 3 of the drawings, comprises a spindle 16 mounted within the tubular control 14 and has mounted on its top end, the seat support member 12. The lower end of the spindle .16 is journaled in the lower end of the tubular casing '14 by a conventional ball race 17. The upper end of the spindle .16 is journaled in the casing by means of a upper sleeve 18- which is secured against longitudinal and rotative movement therein by the pin 1 5 and a set screw 19. A lower sleeve 20 is mounted on the spindle below the upper sleeve 18, the lower sleeve 20 being pinned to the spindle by means of pin 21 whereby the spindle and sleeve 20 move together. The pin 21 is extended so as to project through a rectangular slot formed in the tubular control 14, the width of the slot being arranged and proportioned to permit up and down movement of the spindle and the length being such that it permits the spindle to have limited rotative movement on either side of a centered position which will be described later. A compression spring 23 surrounds the spindle I16 and is captured between the ball race 17 and the second sleeve 20. The compression spring 23 resiliently supports the spindle '16 which reacts as weight is applied to and removed from the seat 11.

The contiguous ends of the upper and lower sleeves 18, 20 are each respectively formed with oomplernental upper and lower plate cams which are constructed and arranged to return the spindle to a centered position as hereinafter described. The lower plate cams on the end of the lower sleeve 20 are of semi spiral form and are indicated by the numerals 2'4, 25. The contiguous end of .the upper sleeve 18 is formed with similar upper cam plates indicated by the numerals 26, 27. These cam plates nest together with their faces abutting in the centered position, and react to return the spindle to the centered position whenever the spindle is rotated from that position and the applied force is removed from the seat. The rotative movement of the spindle in either direction for the centered position is limited by the pin 21. The circumferential length of the slot 22 is such that the pin 21, serving as a stop, stops the rotation of the spindle before the cams can slam together.

It will be seen from the foregoing that as soon as a weight is applied to the seat 11, the spindle will move downwardly separating the plate cams. The seat 11 can then be swivelled in either direction from a centered position, the pin 21 limiting the swivelling action in the present illustration to less than 90 in either direction from that centered position. The cams, as shown in FIGURE 2, are then out of contact, in which position the tips of the lower cam plates are at the half way position between the highest and lowest point of the upper cam. If a person who is sitting on the seat, swivels the seat from the centered position and then rises from the seat, the compression spring 23 will react to bring the cam plates together which cooperate to return the spindle to its centered position.

Referring now to FIGURE 4, which illustrates the structure presently in use, the parts which correspond to similar parts described and illustrated in conjunction with FIGURES 1 to 3 have been given the same numerals. :In this construction, the downward movement of the spindle is arrested by the thrust Washer 25. The crests of the cams form the stop for limiting the rotation of the spindle with constant slamming of the surfaces.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. A memory swivel for a swivel chair comprising, in combination, a base member having an upright tubular fixed post in which is mounted a tubular control, a chair spindle mounted in said tubular control for rotative and longitudinal movement therein, spring means resiliently supporting said spindle, upper and lower sleeves mounted in end-to-end relationship within said tubular control, the upper sleeve being secured to the tubular control, and a pin extending diametrically through the spindle and the lower sleeve thereby securing it to the spindle to be movable therewith, said sleeves having on their opposed contiguous ends plate cams norm-ally out of engagement when said spindle is under load and cooperating to re turn said spindle to a centered position when said spindle is not under load and an enlarged slot in the tubular control in registration with lower sleeve and an extension on the pin projecting into the slot, thereby limiting the rotative movement of the spindle to about 90 in either direction from the centered position without interferring with the tree up and down movement of the spindle and without injurious pressures on the cams.

References Cited UNITED STATES PATENTS 1,895,226 1/1933 Kupski 248-417 1,897,676 2/1933 Ries 248417 2,691,407 10/1954 Kupski 248417 FRANCIS K. ZUGEL, Primary Examiner.

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