US3881713A

US3881713A - Rocker spring unit

Info

Publication number: US3881713A
Application number: US363032A
Authority: US
Inventors: T Bob Joyce
Original assignee: Hickory Springs Manufacturing Co
Current assignee: Hickory Springs Manufacturing Co
Priority date: 1973-05-23
Filing date: 1973-05-23
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

A rocker spring unit having a top plate member with laterally projecting tab sections at its side edges for chair attachment and rocker spring seat-forming bosses at its front and rear edges is improved by providing the tab sections with at least one angled edge tapering from a widened reinforcing base therefor and by providing the rear bosses of the top plate member with inward and downward angled seat portions for straight line bottoming of the rocker springs.

Description

O United States Patent 11 1 [111 3,881,713

Joyce May 6, 1975 ROCKER SPRING UNIT 3,547,393 12/1970 Gordin 248/385 [75] Inventor: T. Bob Joyce, Mansfield, Ark.

Primary Examiner-Richard A. Schacher Asslgneel P PE Manufaaurmg Assistant ExaminerJeffrey V. Nase Company, Hwkory, Attorney, Agent, or Firm-Richards, Shefte & 22 Filed: May 23, 1973 Pmckfley 21 A l. N 363032 1 pp 0 57 ABSTRACT A rocker spring unit having a top plate member with [52] jg b izg i laterally projecting tab sections at its side edges for [51] Int Cl chair attachment and rocker spring seat-forming [58] Fie'ld 94 bosses at its front and rear edges is improved by prog f i l viding the tab sections with at least one angled edge tapering from a widened reinforcing base therefor and [56] References Cited by providing the rear bosses of the top plate member with inward and downward angled seat portions for UNlTED STATES PATENTS straight line bottoming of the rocker springs. 2,012,575 8/1935 Mclnemey 267/94 2,775,287 12/1956 Mantegna 5/351 8 Chums, 5 Drawlng Flgures PATH-HEB um 61975 SHEET 2 OF 2 b2 Fig. 5

PRIOR ART BACKGROUND OF THE INVENTION The present invention relates to rocker spring units generally and, more particularly, to rocker spring units of the type disclosed in U.S. Pat. Nov 3,547,393. That patent discloses a device having top and bottom plate members which are pivotally connected about a centrally disposed horizontal pivot axis at opposed side flanges thereof which are depending and upstanding, respectively. Rocker springs extend between the plate members and are attached thereto at seating bosses disposed at the front and rear edges of the plate members. Additionally, the top plate member has several laterally projecting tab sections which are cut out of the side flanges and which have apertures for attachment of the device to the seat portion of a chair structure.

One problem with the unit of U.S. Pat. No. 3,547,393, and with other units similar to it, is that the chair attaching tab sections are difficult to strengthen adequately and tend to fail with a troublesome frequency. A second problem is that the rocker spring service life is often shortened objectionably due to eccentric bottoming as a result of their common arrangement. The present invention deals with both of these problems effectively.

SUMMARY OF THE INVENTION Briefly described, the rocker spring unit of the present invention has top and bottom plate members, rocker springs extended between and attached to the plate members, and means allowing the top plate member to rock relative to the bottom plate member. The top plate member has apertured tab sections which project laterally from its side edge portions and which have at least one angled edge tapering from a widened reinforcing base for the tab section. Preferably, the top plate member also has embossed reinforcing ribs extending into the tab sections, most preferably adjacent an angled edge thereof. It is further preferred that the top plate member be rectangularly shaped, have a tab section adjacent each of its corners, and have embossed ribs extending between the tab sections.

A second embodiment of the present invention has, in addition to any or all of the above features, a top plate member with opposed depending side flanges, a bottom plate member with opposed upstanding side flanges extending into face-to-face relation to the top plate member side flanges, means for pivotally connecting the side flanges of the top plate member to those of the bottom plate member at a centrally disposed horizontal pivot axis, and rocker springs extended between and attached to the plate members. The plate members have bosses displaced adjacent their front and rear edge portions, which form attaching seats for the rocker springs, and the bosses adjacent the rear edge portion of the top plate member have downward and inward angled seat portions to provide for straight line bottoming of the rocker springs attached thereto. Preferably, the plate members are rectangularly shaped and a boss is located closely adjacent each of their corners.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective illustrating a rocker spring unit embodying the present invention;

FIG. 2 is a plan view corresponding to FIG. 1;

FIG. 3 is a vertical section taken along line 3-3 of FIG. 1;

FIG. 4 is a sectional illustration of the manner in which rocker springs bottom according to usual prior art practices; and

FIG. 5 is a sectional illustration similar to FIG. 3 but showing the rear of the rocker spring unit pivoted downwardly for rocker spring bottoming according to the present invention, some parts being removed from the drawing for clarity of illustration.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 13 illustrate a device, made according to the present invention, which is generally comprised of a rectangular top plate member 10, a rectangular bottom plate member 12, front rocker springs 14, rear rocker springs 14', and a swivel base 16. The

plate members

10, 12 are aligned vertically and five rocker, springs l4, 14' are attached theretoand extended therebetween, one closely adjacent each corner of the

plate members

10, 12 at the front and

rear edge portions

18, 20 thereof and one located rearward of the centers of the

plate members

10, 12 and approximately equidistant from the side edge portions 22 thereof. The top plate member '10 has a pair of opposed depending side flanges 24 which extend into face-to-face relation to a pair of opposed upstanding side flanges 26 on the bottom plate member 12. The bottom plate member side flanges26 are disposed outward of the top plate member side flanges 24 and are pivotally connected to the top plate member side flanges 24 by a pair of aligned rivets 28 about a centrally disposed horizontal pivot axis 30 (see FIG. 3). Finally, the bottom plate member 12 is assembled with the swivel base 16 in the usual manner as noted further below.

The top plate member 10 has four tab sections 32, each located adjacent one corner thereof and laterally projecting from a side edge portion 22 thereof. The tab sections 32 are cut out of the side flanges 24 and have apertures 34 for attachment of the seat portion of a chair structure (not shown). Each of the four tab sections 32 has an angled edge 36 which tapers from a reinforcing base 38 at a side edge portion 22 of the top plate member 10.

As stated above, tab sections such as those described in U.S. Pat. No. 3,547,393 are difficult to strengthen adequately. The use of angled edges 36 on the tab sections 32 of the illustrated device provide the tab sections 32 with a widened and substantially stronger reinforcing base 38. For additional strengthening of the tab sections 32, the top plate member ll) has two embossed ribs 40 which extend diagonally between and into the tab sections 32 adjacent the angled edges 36 thereof, although it is not necessary that the embossed ribs 40 extend completely across the entire width of the top plate member 10, or that they be located in any particular relation to the tab sections 32 as long as they extend into these sections so as to provide the full strengthening effect of such ribs.

Both

plate members

10, 12 have displaced therein five bosses 42 which form attaching seats for the

rocker springs

14, 14. Two of the bosses 42 are located at each front and

rear edge portion

18, 20 of the

plate members

10, 12 closely adjacent the corners thereof. The remaining bosses 42 are partially cut out of the

plate members

10, 12 and are located one on each of the

plate members

10, 12 rearward of the center and approximately equidistant from the side edge portions 22 thereof. Each of the bosses 42 has a raised inwardlyextending portion 44 displaced therein which engages and holds the end of the rocker spring 14 or 14' which is seated thereat.

According to the present invention, the bosses 42 adjacent the rear edge portion 20 of the top plate member 10 have inward and downward angled seat portions 46 (see FIG. 3). As stated above, the rear rocker springs 48 of a device like that shown in U.S. Pat. No. 3,547,393 (as illustrated in FIG. 4) exhibit eccentric bottoming when the top plate member 50 is tilted backward relative to the bottom plate member 52, thereby causing complicated stressing on the rocker springs 48 which tends to lessen service life. Straight line bottoming (as illustrated in FIG. 5) and an approximate 50% increase in the useful life of the rocker springs 14 is brought about by providing the top plate member with inclined rear seat portions 46 as described above, which disposes the top and bottom rear spring seat portions generally parallel when the unit is fully rocked rearward (FIG. 5) until the springs are fully compressed, with the result that the spring coils are in substantially full contact throughout rather than contacting only at the rearmost edges as in the prior art devices.

The required degree of inclination of the seat portions 46 depends upon the distance from the pivot axis to the seat portions, the space between the plate members l2 and 10 in a neutral position, and the bottomingout or fully compressed height of the springs 48. In the embodiment shown in FIGS. 1-3, which incorporates a design adopted for actual use, the degree of inclination of the seat portions 46 from the plane of the top plate member 10 is approximately 10.

Although in the illustrated embodiment only the rearmost two spring seat portions are inclined, it should be understood that other of the spring seat portions can be similarly inclined, as for example the center spring seat portion that is adjacent the rear edge of the top plate member 10.

The bottom plate member 12 has a large, centrally located aperture (not shown) for attachment by a central staking rivet (not shown) to the swivel base 16 and is arranged for swivel mounting about the central staking rivet by complementary grooves (not shown) concentrically formed in the lower face of the bottom plate member 12 and in the upper face of the swivel base 16 to contain bearing balls (not shown) that support the swiveling action in the manner described in the abovementioned U.S. Pat. No. 3,547,393.

The present invention has been described in detail above for purposes of illustration only and is not intended to be limited by this description or otherwise to exclude any variation or equivalent arrangement that would be apparent from, or reasonably suggested by,

the foregoing disclosure to the skill of the art.

I claim:

1. In a rocker spring unit comprising a top plate member having opposed depending side flanges, a bottom plate member having opposed upstanding side flanges extending into face-to-face relation to said top plate member side flanges, means pivotally connecting said top plate member side flanges to said bottom plate member side flanges at a centrally disposed horizontal pivot axis, rocker springs extended between and attached to said plate members, and bosses displaced in said plate members adjacent front and rear edge portions thereof to form attaching seats for said rocker springs, the improvement which comprises angled seat portions in said bosses adjacent said rear edge portion of said top plate member, said seat portions being angled downwardly and forwardly for straight line bottoming of the rocker springs attached thereto upon downward rocking of said top plate member rear edge portion.

2. A rocker spring unit as defined in claim 1 and further characterized in that said downwardly and forwardly angled seat portions are disposed to be generally parallel with the corresponding bottom plate seat portions when the rocker springs therebetween are fully compressed.

3. A rocker spring unit as defined in claim 1 and further characterized in that said downwardly and forwardly angled seat portions are inclined approximately 10 degrees from the plane of said top plate member.

4. A rocker spring unit as defined in claim 1 and further characterized in that said plate members are rectangularly shaped and a boss is located closely adjacent each comer of said plate members.

5. A rocker spring unit as defined in claim 1 and further characterized in that said top plate member has apertured tab sections laterally projecting from side edge portions thereof for attachment of said unit to the seat portion of a chair structure, said tab sections having at least one angled edge for tapering of said sections from a widened reinforcing base.

6. A rocker spring unit as defined in claim 5 and further characterized in that said top plate member has embossed ribs extending into said widened reinforcing bases of said tab sections for additional reinforcement thereof.

7. A rocker spring unit as defined in claim 6 and further characterized in that said embossed ribs extend into said tab sections adjacent an angled edge thereof.

8. A rocker spring unit as defined in claim 7 and further characterized in that said top plate member is rectangularly shaped; in that said top plate member has a tab section located adjacent each corner of said top plate member; and in that said embossed ribs extend between said tab sections.

Claims

3. A rocker spring unit as defined in claim 1 and further characterized in that said downwardly and forwardly angled seat portions are inclined approximately 10* degrees from the plane of said top plate member.

4. A rocker sprIng unit as defined in claim 1 and further characterized in that said plate members are rectangularly shaped and a boss is located closely adjacent each corner of said plate members.