US3776608A

US3776608A - Circulating ball bearing slide

Info

Publication number: US3776608A
Application number: US00321535A
Authority: US
Inventors: R Lambert; W York; M Fall; C Scalf; H Fall
Original assignee: Individual
Current assignee: General Devices Co Inc
Priority date: 1973-01-05
Filing date: 1973-01-05
Publication date: 1973-12-04
Anticipated expiration: 1990-12-04

Abstract

A slide assembly comprising a relatively fixed elongated track member, a relatively movable elongated track member, and an intermediate elongated track member movable relative to the fixed and movable track members. The intermediate track member provides, at each of its upper and lower longitudinal edge portions and on opposite sides of a vertically and longitudinally extending center plane, longitudinally extending ball bearing raceways. End pieces at each end of the intermediate member provide a ball bearing passageway communicating between one of the upper raceways and the lower raceway on the opposite side of the center plane and another passageway communicating between the other upper raceway and the other lower raceway on the opposite side of the plane. Ball bearings substantially fill the raceways and their communicating passageways, and the fixed and movable track members include runner portions extending respectively into and engaging the ball bearings in the adjacent upper and lower raceways.

Description

United States Patent 1 1 Fall et al.

[ CIRCULATING BALL BEARING SLIDE [75] Inventors: Herbert S. Fall; Martin K. Fall;

Maxwell S. Fall; Charles E. Scalf; Ronald D. Lambert; William D. York, all of Indianapolis, Ind.

[73] Assignee: Herbert S. Fall, Indianapolis, Ind.

[22] Filed: Jan. 5, 1973 21 App]. No.: 321,535

[52] US. Cl. 308/3.8, 312/339 [51] Int. Cl. F16c 29/00 [58] Field of Search 308/3.8, 6 C;

[ Dec. 4, 1973 Primary ExaminerManuel A. Antonakas Assistant Examiner-R. H. Lazarus AttorneyWilliam R. Coffey vides, at each of its upper and lower longitudinal edge portions and on opposite sides of a vertically and 1ongitudinally extending center plane, longitudinally extending ball bearing raceways. End pieces at each end of the intermediate member provide a ball bearing passageway communicating between one of the upper raceways and the lower raceway on the opposite side of the center plane and another passageway communicating between the other upper raceway and the other lower raceway on the opposite side of the plane. Ball bearings substantially fill the raceways and their communicating passageways, and the fixed and movable track members include runner portions extending respectively into and engaging the ball bearings in the adjacent upper and lower raceways.

21 Claims, 13 Drawing Figures PATENTED 41975 SHEET 1 (IF 2 CIRCULATING BALL BEARING SLIDE The present invention'relates to drawer slides, and more particularly to circulating ball bearing drawer slides'of the 'type shown in US. Pat. No. 3,059,978 issued Oct. 23, 1962 on an application by Mr. Herbert S. Fall.

Circulating ball bearing drawer slides have been on the market for several years now and have been used movably to support relatively heavy loads. For instance, circulating ball bearing slides are particularly suited for movably supporting drawers in cabinets filled with electronic gear. Such slides are attractive because they provide great load-carrying capacity while occupying a minimum amount of space in a horizontal direction. Of course, the circulating ball bearings are an ideal means for reducing friction, thereby to make it much easier to move the supported load rectilinearly.

In circulating ball bearing drawer slides of the type shown in US. Pat. No. 3,059,978, the ball bearings circulate about closed-loop raceways or paths. Such slides include a first elongated track member, a second elongated track member generally parallel to the first track member, and a third elongated track member disposed between and generally parallel to the first and second track members. This third member provides, at each of its upper and lower longitudinally extending edge portions, a pair of laterally spaced apart, longitudinally extending ball bearing raceways, one raceway adjacent the first track member and one raceway adjacent the second track member. Conduit means at each end of the third track member provide passageways continuing the raceways around the ends of the third track member. The first and second track members provide longitudinally extending runners which extend respectively into the adjacent upper and lower raceways to engage the ball bearings therein. Thus, when the second and third track members are moved relative to the first track member, the ball bearings circulate along the raceways and through the passageways on the third track member. This operation is disclosed in the said US. Pat. No. 3,059,978.

As the ball bearings circulate, the ball bearings leaving the ends of the raceways must, of course, move laterally. It has been discovered that slides having heretofore unexpectedly increased load-life characteristics can be obtained by constructing the said conduit means at the ends of the third track member such that the ball bearings moving through the conduit means move vertically out of load bearing contact with the runners on the first and second track members when the ball bearings are moving transversely around the ends of the third track member. The manner in which this is accomplished, in accordance with the present invention, will be discussed in detail as this description progresses.

It hasfurther been discovered that the load-life characteristics of circulating ball bearing slides may be significantly increased and friction decreased by placing rollers on the third track member, i.e., the intermediate track member, which rollers rollably engage thefirst and second track members to keep them from moving or twisting out of their respective vertical planes. Preferably, as will be more fully explained hereinafter, such rollers are journal mounted on the said third member to be adjacent the upper and lower raceways.

It has also been discovered that the load-life of circulating ball bearing slides can be significantly increased by'providing means for synchronizing the movement of the intermediate member with the movable member. For instance, if the said first track member is attached to the frame of the cabinet and the second track member is attached to the drawer, it is desirable for the third track member to move relative to the cabinet in the same direction that the second track member moves and at one-half the velocity of the second track member. In accordance with the present invention, this is accomplished by a cable drive system of the type disclosed in US. Pat. No. 3,687,505 issued Aug. 29, l972 on an application by Messrs. Maxwell S. Fall and Ronald D. Lambert.

Other objects and features of the present invention will become apparent as this description progresses.

To the accomplishment of the above and related objects, this invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that change may be made in the specific constructions illustrated and described, so long as the scope of the appended claims is not violated.

In the drawings:

FIG. 1 is a fragmentary plan view of a slide constructed in accordance with the present invention;

FIG. 2 is a fragmentary elevational view of the end of the slide shown in FIG. 1;

FIGS. 3, 4 and 5 are, respectively, sectional views taken along the lines 33, 4-4 and 55 in FIG. 2;

FIG. 6 is a somewhat diagrammatical top view of the entire slide;

FIG. 7 is an enlarged fragmentary end view of the intermediate track member of the slide;

FIG. 8 is an elevational view of one of four identical end pieces used on the intermediate track member to provide passageways connecting opposite upper and lower raceways;

FIG. 9 is a sectional view taken along the line 99 in FIG. 8;

FIG. 10 is a sectional view taken along the line 1010 in FIG. 8;

FIG. 11 is a fragmentary top view of an end portion of a different embodiment of the present invention;

FIG. 12 is a perspective view of the passageway providing end pieces for the intermediate track member of the embodiment of FIG. 11; and

FIG. 13 is a sectional view taken along the line 13-13 in FIG. 12.

Referring now to the drawings and particularly FIGS. 1-10, it will be seen that the circulating ball bearing slide, indicated generally by the reference numeral 10, comprises a relatively stationary track member 12, an intermediate track member 14, and a movable track member 16. As indicated previously, the stationary track member 12 may be rigidly fastened to the frame 18.0f a cabinet by means such as the illustrated screws 19 (FIG. 2). The movable track member 16 may be rigidly fastened to a drawer 20 by means such as screws, the holes for which are indicated at 21.

The intermediate track member 14, in the illustrative and preferred embodiment, includes a vertically and longitudinally extending center member 24 which may be a strip of steel or aluminum or some other desired material formed as will be discussed hereinafter. The center member 24 defines a vertically and longitudinally extending center plane with reference to which the slide 10 is preferably symmetrical in cross section. In the illustrative embodiment, strips 26 are welded or otherwise securely fastened to'opposite sides of the center member 24 to extend longitudinally along the upper and lower longitudinal edges of the center member. These strips 26 serve to retain the ball bearings in the raceways as will be discussed hereinafter.

The center member 24 is sandwiched between vertically and longitudinally extending

side members

28, 30 which may be, for instance, formed of strip steel or strip aluminum. These

side members

28, 30 may be spot welded or otherwise securely fastened to the center member 24. Preferably, the

members

24, 26, 28, 30 will be welded together to provide a strong, unitary member having great structural strength in all directions, but particularly in the vertical direction.

The upper and lower longitudinally extending edge portions of the

side members

28, 30 are formed to provide, on opposite sides of the center member 24, a pair of laterally spaced apart, longitudinally extending upper raceways 32 and a pair of laterally spaced apart, longitudinally extending lower raceways 34. Ball bearings 36 substantially fill these raceways and their connecting passageways to be hereinafter described. As best seen in the sectional view of FIG. 3, each

raceway

32, 34 is formed by a horizontally outwardly and longitudinally extending floor section 40 and, from the distal edge of this floor section, a vertically extending wall section 42, the distal edge portion 44 of which is disposed inwardly toward the center member 24. It will be appreciated that this distal edge portion 44 cooperates with the adjacent strip 26 to keep the ball bearings 36 from moving vertically out of their raceways. That is, the distance between each distal edge portion 44 and the adjacent strip 26 is less than the diameter of the ball bearings 36 such that the ball bearings are prevented from moving vertically out of the

raceways

32, 34. It will be seen that the upper and lower edge portions of the center member 24 adjacent the strips 26 separate the

raceways

32, 34. A

One of the objectives of the present invention is to hold the

outer track members

12, 16 for movement in fixed vertical and longitudinally extending planes relative to the intermediate track member 14. In the illustrative and preferred embodiment, this stabilizing of the track members is accomplished by means of a plurality of rollers 48 journal mounted on the intermediate track member 14 for rotation about vertically extending axes lying in the vertically and longitudinally ex tending center plane defined by the center member 24 of the track member 14. In the illustrative embodiment (FIG. 6), there are four pairs of longitudinally spaced apart rollers 48, each pair including an upper roller 48 adjacent the raceways 32 and a lower roller 48 adjacent the lower raceways 34. As best seen in FIG. 3, the outer peripheries of the rollers 48 roll against the inner surfaces of the

track members

12, 16. The rollers 48, which preferably are plastic and cylindrical in shape as illustrated, are effective to prevent racking or twisting of the

track members

12, 14, 16. This feature adds significantly to the load-life capacity of the slide 10, and reduces friction caused by twisting of

members

12, 14 and 16.

The rollers 48 of each pair may be journal mounted on a vertically extending axle 50 which may be welded or otherwise securely fastened to an axle plate 52 which is secured to the intermediate track member 14 by means such as the illustrated screws 54. Of course, the intermediate track member 14 must be provided with cutouts, such as are indicated at 55 (FIG. 2), to accommodate the vertically spaced apart rollers 48 and the axle 50.

Pulley means, indicated generally by the reference numeral 56 in FIG. 3, is journal mounted on the intermediate track member 14 for rotation about a vertically extending axis.

Flexible strands

58, 60 are trained about this pulley means 56 and connected to the

track members

12, 16 to provide a driving connection be tween the three track members. Particularly, in the illustrative embodiment, as viewed in FIG. 6, the ends of the strand 58 are connected to the adjacent right-hand ends of the

track members

12 and 16 as indicated at 62 while the ends of thestrand 60 are connected to the adjacent left-hand ends of the

track members

12, 16 as indicated at 64. This arrangement provides a driving connection such that, when the track member 16 moves in the direction of the arrow 72 relative to the track member 12, the intermediate track member 14 also moves in the direction of the arrow 72, but at onehalf the velocity of the track member 16. Then, when the track member 16 is moved back in the direction opposite to the arrow 72, the track member 14 moves in the same direction but at one-half the velocity. The purpose of the synchronizing cable drive is to make sure that, when the movable track member 16 moves, the intermediate track member 14 moves a proportional distance. This simultaneous synchronized movement prevents uneven wear of the raceways and ball bearings, thereby increasing the loadlife capacity of the slide.

The upper and lower longitudinal edge portions of the track members l2, 16 are formed to provide longitudinally downwardly and upwardly extending runners 68, which, respectively, extend into and engage the ball bearings 36 in the upper and

lower raceways

32, 34. It will be appreciated that the

runners

68, 70 are disposed in the spaces between the distal edge portions 44 and the strips 26 of the raceways. As described in the US. Pat. No. 3,059,978 cited above, loads placed upon the movable track member 16 are transmitted by the ball bearings and the intermediate track member 14 to the relatively fixed track member 12. Movement of the track member 16, in accordance with the present invention, is accompanied by circulation of the ball bearings 36 in the

raceways

32, 34.

In the illustrative and preferred embodiment, the opposite end portions of the intermediate track member 14, and particularly the center member 24 of that track member, are formed to provide a pair of

apertures

74, 76. As best seen in FIGS. 2 and 7, these

apertures

74, 76 are longitudinally spaced apart and vertically elongated with the upper and lower ends of the apertures being adjacent the planes of the upper and

lower raceways

32, 34.

In accordance with the present invention, conduit means are provided at each end of the intermediate track member 14, each conduit means providing a ball bearing 36 passageway communicating between the upper raceway 32 adjacent the track member 12 and the lower raceway 34 adjacent the track member 16 and another ball bearing 36 passageway communicating between the upper raceway 32 adjacent the track member 16 and the lower raceway 34 adjacent the track member 12. In the llustrative embodiment, this conduit means includes, at each end of the intermediate track member 14 and on opposite sides of the apertured center member 24,

end pieces

82, 84 which may preferably be identical. Each

end piece

82, 84 is formed to include an outer passageway 90 which comr'nunicates with the outer aperture 74 and an inner passageway 96 which communicates with the inner aperture 76. Particularly, the vertically extending portions of the

passageways

90, 96 are respectively in registry with the

apertures

74, 76 when the

end pieces

82, 84 are assembled on opposite sides of the end portion of the center member 24.

Referring to FIGS. 4 and 5, it will be seen that the mating passageways 90 and outer aperture 74 provide.

communication between the upper raceway 32 adjacent the track member 12 and the lower raceway 34 adjacent the track member 16 (FIG. 4) while the mating passageways 96 and the inner aperture 76 provide communication between the upper raceway 32 adjacent the track member 16 and the lower raceway 34 adjacent the track member 12. The ball bearings, therefore, move vertically as well as horizontally through the center plane of the intermediate track member 14 as the ball bearings move about the ends of the track member 14. g p

The

end pieces

82, 84, and particularly their

passageways

90, 96, are proportioned and designed suchthat, the ball bearings 36leaving the ends of the upper and

lower raceways

32, 34 move, respectively, vertically downwardly and upwardly to be out of load bearing contact with the

runners

68, 70. Thus,no load is being applied to the ball bearings when they must move vertically and horizontally through the

passageways

90, 96 and

apertures

74, 76.

Each of the

end pieces

82, 84 is provided with a depression 100 in its exterior side, which depression provides clearance for the

strands

58, 60 as well as the mechanical stops, such as indicated at 102, which limit the longitudinal movement of the track members. Further, illustratively, each

end piece

82, 84 is provided with apertures 106 for use in mounting the end pieces to the intermediate track member which is provided with registering apertures 107; Fastening elements, such as the screws 108, may extend through these

apertures

106 and 107 to fasten the end pieces to the intermediate track member.

Referring now to FIGS. 11, 12 and 13, another preferred embodiment of the present invention will be discussed, this embodimentincluding end pieces 120 fastened to opposite ends of the intermediate track member 14 to provide passageways communicating between the raceways provided by the intermediate track member 14. The end pieces 120, only one of which is shown, are provided with abutment faces 122 which abut against the track member 14. The end pieces 120 may be welded or otherwise securely fastened to the track member 14 as disclosed in US. Pat. No. 3,059,978 cited above. Each end piece 120 is formed to provide upper and

lower passageways

126, 128. The upper passageways 126 provide communication between the upper raceways on the intermediate track member 14 and the lower passageways 128 provide communication between the lower raceways on the intermediate track member. Each

passageway

126, 128 includes a floor 130 and a peripherally and vertically extending wall 132.

As best seen in FIG. 13, the floor 130 of the passageway 126 is inclined downwardly at an angle of approximately 5 to indicated at 134 while the floor'130 of the passageway 128 is inclined upwardly at a similar angle 134. Particularly, the floors 130 of the

passageways

126, 128 are inclined downwardly and upwardly, respectively, from the ends of the floors of the upper and lower raceways of the intermediate track member so that the ball bearings moving through the passageways are moved vertically out of load bearing contact with the downwardly and upwardly extending runners of the

track members

12, 16 when the ball bearings are moving transversely around the ends of the intermediate track member. That is, the end pieces 120 are proportioned and designed such that the circulating ball bearings 36 are moved out of load bearing engagement with the downwardly and upwardly extending runners of the

track members

12, 16 when the ball bearings move through the

passageways

126, 128. Thus, in accordance with the present invention, a load is applied to the ball bearings 36 only when they are moving longitudinally along the

raceways

32, 34 and not when they are moving transversely about the ends of the intermediate track member 14.

The ball bearings 36 are prevented from moving vertically out of the

passageway

126, 128 by retainer plates 136 fastened to the upper and lower ends of the end pieces by means such as screws 138 which thread into tap holes 140 in the end pieces.

Slides constructed in accordance with the present invention have significantly improved load-life capacities. A pair of slides 10 constructed in accordance with the embodiment of FIGS. l-l0 are able movably to support loads of 450 lbs. for more than 25,000 cycles of 18 inches extension. A cycle is defined as one complete cycle of movement of the

track member

16, 18 inches from its retracted position to its projected position and then back to its retracted position. This achievement is significant when the length, width and height of the slide 10 is compared to other slides having similar load-life capacities. The slide 10, when retracted, is approximately 26 inches long, 1% inches wide and 3% inches tall.

What is claimed is:

l. A slide assembly comprising a first elongated track member, a second elongated track member generally parallel to said first track member and a third elongated track member disposed between and generally parallel to said first and second members, each said track member having upper and lower longitudinally extending edge portions, said third track member providing, at each of its upper and lower longitudinally extending edge portions, a pair of laterally spaced apart, longitudinally extending ball bearing raceways, one raceway adjacent said first track member and one raceway adjacent said second track member, conduit means at each end of said third track member providing a ball bearing passageway communicating between the upper raceway adjacent said first track member and the lower raceway adjacent said second track member and another ball bearing passageway communicating between the upper raceway adjacent said second track member and the lower raceway adjacent said first track member, and ball bearings substantially filling said raceways and their communicating passageways, said first and second track members including longitudinal portions extending respectively into and engaging the ball bearings in the upper and lower raceways adjacent said track members.

2. The assembly of claim 1 including roller means journal mounted on said third track member rollably to engage said first and second track members.

3. The assembly of claim 1 in which said third track member defines a vertically and longitudinally extending center plane parallel to said raceways, and including a plurality of rollers joumalled on said third track member rollably to engage said first and second track members, the journal axes for said rollers being vertically extending and parallel to said center plane.

4. The assembly of claim 3 in which said rollers include at least two longitudinally spaced apart pairs of rollers journalled on vertical axes lying in said center plane such that the outer periphery of each roller engages said first and second track members, the rollers of each pair being vertically spaced apart to be adjacent, respectively, said upper and lower raceways.

5. The assembly of claim 1 including pulley means joumalled on a transverse axis on said third track member, and flexible strand means anchored to said first and second track members and trained about said pulley means to establish a driving connection between said track members whereby, when one of said first and second track members is held stationary and the other of said first and second track members is moved in either direction longitudinally, the third track member will be moved in the same direction and at one-half the velocity.

6. The assembly of claim 1 in which said third track member is formed such that said laterally spaced raceways at said upper and lower edge portions are on opposite sides of and parallel to a vertically and longitudinally extending center plane.

7. The assembly of claim 6 in which said third track member is formed to provide, at each of its ends, a pair and another of apertures therethrough, said conduit means including, on each side of each end of said third member, block means providing a passageway leading downwardly from the raceway disposed thereabove to one of said apertures anda other passageway leading upwardly from the raceway disposed therebelow to the other of said apertures.

8. The assembly of claim 7 in which said apertures of each pair are vertically elongated and longitudinally spaced apart.

9. The assembly of claim 6 in which said third track member includes a pair of longitudinally and vertically extending side members and a longitudinally and vertically extending center member sandwiched between said side members, the vertical center of said center member lying in said center plane, the upper and lower longitudinal edges of each side member being formed to provide outwardly extending floor sections and vertically extending wall sections bounding said upper and lower raceways, the upper and lower longitudinal edges of said center member providing the inner vertically extending wall sections for said raceways.

10. A slide assembly comprising a relatively fixed elongated track member having upper and lower longitudinal edge portions, a relatively movable elongated track member having upper and lower longitudinal edge portions, an intermediate elongated track member generally parallel to and disposed between said fixed and movable track members, said intermediate track member having upper and lower longitudinal edge portions and being longitudinally movable relative to said fixed and movable track members, said intermediate track member defining a vertically and longitudinally extending center plane and providing, at each of its upper and lower longitudinal edge portions and on opposite sides of said center plane, longitudinally extending ball bearing raceways, means at each end of said intermediate member for providing a ball bearing passageway communicating between one of said upper raceways and the lower raceway on the opposite side of said center plane and another passageway communicating between the other said upper raceway and the other lower raceway on the opposite side of said center plane, and ball bearings substantially filling said raceways and their communicating passageways, the upper and lower longitudinal edge portions of said fixed and elongated track members extending respectively into and engaging the ball bearings in the adjacent upper and lower raceways.

11. The assembly of claim 10 including a plurality of rollers joumalled on said intermediate track member rollably to engage said first and second track members, the journal axes of said rollers being parallel to said center plane.

12. The assembly of claim 11 in which said track members extend horizontally, said rollers including at least two longitudinally spaced-apart pairs of rollers joumalled on vertical axes lying in said center plane such that the outer periphery of each roller engages said fixed and movable track members, the rollers of each pair being vertically spaced apart to be adjacent, respectively, said upper and lower raceways.

13. The assembly of claim 10 including pulley means joumalled on a transverse axis on said intermediate track member, and flexible strand means anchored to said fixed and movable track members and trained about said pulley means to establish a driving connection between said track members whereby, when said movable track member is moved in either direction longitudinally, the intermediate track member moves in the same direction and at one-half the velocity.

14. The assembly of claim 12 including pulley means joumalled on a transverse axis on said intermediate track member, and flexible strand means anchored to said fixed and movable track members and trained about said pulley means to establish a driving connection between said track members whereby, when said movable track member is moved in either direction longitudinally, the intermediate track member moves in the same direction and at one-half the velocity.

15. The assembly of claim 10 in which said intermediate track member is formed to provide, at each of its ends, a pair of apertures therethrough, said conduit means including, on each side of each end of said intermediate track member, block means providing a passageway leading downwardly from the raceway disposed thereabove to one of said apertures and another passageway leading upwardly from the raceway disposed therebelow to the other of said apertures.

16. The assembly of claim 15 in which said intermediate member includes a pair of longitudinally and vertically extending side members and a longitudinally and vertically extending center member, the vertical center of which lies in said center plane, the upper and lower longitudinal edges of each side member being formed to provide outwardly extending floor sections and vertically extending wall sections bounding said upper and lower raceways, the upper and lower longitudinal edges 9 of said center member providing the inner vertically extending wall sections for said raceways.

17. The assembly of claim 16 in which said apertures of each pair are formed in said center member.

18. The assembly of claim 17 in which said apertures are vertically elongated and longitudinally spaced apart.

19. A slide assembly for supporting vertically applied loads comprising a first horizontally elongated track member, a second horizontally elongated track member generally parallel to said first track member, a third horizontally elongated track member disposed between and generally parallel to said first and second members, each said track member having upper and lower longitudinally extending edge portions, said third track member providing, at each of its upper and lower edge portions, a pair of laterally spaced apart, horizontally and longitudinally extending ball bearing raceways on opposite sides of a vertically and longitudinally extending center plane, conduit means continuing said raceways around the ends of said third track member and through said center plane, ball bearings substantially filling said raceways and said conduit means, the upper and lower edge portions of said first and second track members providing downwardly and upwardly longitudinally extending runners extending respectively into said upper and lower raceways on the adjacent side of said center plane to engage said ball bearings therein, said conduit means being proportioned and designed to move said ball bearings vertically out of load bearing contact with said runners when said ball bearings move transversely around the ends of said third track member.

20. The assembly of claim 19 in which said conduit means provides, at each end of said third track member, a passageway extending between one of said upper raceways and the lower raceway on the opposite side of said center plane and another passageway extending between the other said upper raceway and the other said lower raceway on the opposite side of said center plane.

21. The assembly of claim 19 in which said conduit means includes, at each end of said third member, means providing upper and lower passageways connecting, respectively, said upper and lower raceways, each said passageway curving about the end of said third track member, said means being proportioned and designed such that said upper passageways include a floor inclining downwardly from the adjacent ends of said upper raceways and said lower passageways include a floor inclining upwardly from the adjacent ends of said lower raceways.

P0-1050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,776 ,608 Dated December 4 1973 lnventofls) Herbert S. Fall, et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:-

- Column 4, line 65, "llustrative" should be illustrative Column 7, line 36, '(Claim 7, line 3) delete "and another"; line 40, (Claim 7, line 7) "anda other" should be and another Signed and sealed this 23rd day of April 19m.

(SEAL) Attest:

EDWARD PLFLBTCHERJR, Oa MARSHALL DANN Attesting Officer Commissionerof Patents

Claims

1. A slide assembly comprising a first elongated track member, a second elongated track member generally parallel to said first track member and a third elongated track member disposed between and generally parallel to said first and second members, each said track member having upper and lower longitudinally extending edge portions, said third track member providing, at each of its upper and lower longitudinally extending edge portions, a pair of laterally spaced apart, longitudinally extending ball bearing raceways, one raceway adjacent said first track member and one raceway adjacent said second track member, conduit means at each end of said third track member providing a ball bearing passageway communicating between the upper raceway adjacent said first track member and the lower raceway adjacent said second track member and another ball bearing passageway communicating between the upper raceway adjacent said second track member and the lower raceway adjacent said first track member, and ball bearings substantially filling said raceways and their communicating passageways, said first and second track members including longitudinal portions extending respectively into and engaging the ball bearings in the upper and lower raceways adjacent said track members.

3. The assembly of claim 1 in which said third track member defines a vertically and longitudinally extending center plane parallel to said raceways, and including a plurality of rollers journalled on said third track member rollably to engage said first and second track members, the journal axes for said rollers being vertically extending and parallel to said center plane.

5. The assembly of claim 1 including pulley means journalled on a transverse axis on said third track member, and flexible strand means anchored to said first and second track members and trained about said pulley means to establish a driving connection between said track members whereby, when one of said first and second track members is held stationary and the other of said first and second track members is moved in either direction longitudinally, the third track member will be moved in the same direction and at one-half the velocity.

11. The assembly of claim 10 including a plurality of rollers journalled on said intermediate track member rollably to engage said first and second track members, the journal axes of said rollers being parallel to said center plane.

12. The assembly of claim 11 in which said track members extend horizontally, said rollers including at least two longitudinally spaced apart pairs of rollers journalled on vertical axes lying in said center plane such that the outer periphery of each roller engages said fixed and movable track members, the rollers of each pair being vertically spaced apart to be adjacent, respectively, said upper and lower raceways.

13. The assembly of claim 10 including pulley means journalled on a transverse axis on said intermediate track member, and flexible strand means anchored to said fixed and movable track members and trained about said pulley means to establish a driving connection between said track members whereby, when said movable track member is moved in either direction longitudinally, the intermediate track member moves in the same direction and at one-half the velocity.

14. The assembly of claim 12 including pulley means journalled on a transverse axis on said intermediate track member, and flexible strand means anchored to said fixed and movable track members and trained about said pulley means to establish a driving connection between said track members whereby, when said movable track member is moved in either direction longitudinally, the intermediate track member moves in the same direction and at one-half the velocity.

16. The assembly of claim 15 in which said intermediate member includes a pair of longitudinally and vertically extending side members and a longitudinally and vertically extending center member, the vertical center of which lies in said center plane, the upper and lower longitudinal edges of each side member being formed to provide outwardly extending floor sections and vertically extending wall sections bounding said upper and lower raceways, the upper and lower longitudinal edges of said center member providing the inner vertically extending wall sections for said raceways.