Note: Descriptions are shown in the official language in which they were submitted.
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64635-32
DIscLosuRe
This invention relates to drawer slides, more
particularly two or three part channel drawer slides for
file cabinets and the like. Nore particularly this
invention relates to a new ball retainer for use with two
or three part channel slides for use with common steel
balls.
Drawer slides for filing cabinets and the like
are subjected to very heavy loading and constant usage.
As such, the importance of reducing friction and wear is
paramount. Modern drawer slides generally use some type
of bearing cage retainer which is used to retain balls
which move along the raceways of an outer and inner slide
channel.
Modern drawer slides commonly in use today are
of two basic types. The first type of drawer slide iB
one which uses two or three slides and after assembly the
slide are not taken apart for installation into the
cabinet. That is to say that the channel members are not
designed to be separated from one another temporarily to
be installed on drawers and cabinets. This first type of
drawer slide can use an "open retainer" which can be
manufactured from plastics or steel. An open retainer
ha~ ~eating apertures for the balls which have radii
greater than that of the balls. After assembly the balls
are prohibited from lateral displacement by the raceways
of the mating flanges of an inner and outer slide channel
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64635-32
member. The cage serves only to prohibit the balls from
up and down and longitudinal displacement.
In the second type of drawer slide a retainer
is used which has pressed and formed apertures which
generally have a radius which is smaller than the radius
of the ball. Such retainers after assembly secure the
ball for rotation between the aperture and the inside
portion of the flange of the outer channel. The inner
channel flanges also contact portions of the balls when
the slide is assembled but if the inner channel is
removed the balls are maintained in place. This allows
the file cabinet producer to affix the inner slide
channel to the drawer and the outer slide channel to the
cabinet during installation. Thereafter the slide
channels are fitted back together and contact of the
balls takes place on the adjacent raceways of the flanges
of the outer and inner channels. It is this second type
of modern drawer slide to which the present invention is
directed.
In the second type of drawer slide the industry
presently uses a generally standard bearing cage retainer
which is made from a standard light guage piece of
channel. Side flanges are folded upwards from the base
and formed into a plurality of individual flanges on each
side. An aperture is punched in each of the side flanges
with the sides of the aperture pressed inwards to form a
3eat for the ball. The depressed pocket area formed is
made in such a manner that the ball rests on the side
edge~ of the aperture that is to say the points of
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contact are furthest away from the axis of rotation which
is generally vertical running from the base of the
retainer to the top of the flanges.
The inventor has found that such presently used
retainers are not without problems. In particular there
is a great amount of friction created at the points of
contact between the apertures of the retainer and the
balls. During normal ~lide travel the ball is supported
on the friction surfaces. These points of contact occur
on the portions of the ball with the highest surface
velocity, consequently causing considerable resistence to
rotation and promoting skidding of the ball along the
~lide channel raceways.
It is therefore an object of the present
invention to provide a new ball retainer for use with two
and three part drawer slides wherein friction between the
ball and the retainer itself is significantly reduced.
It is also an object of this invention to
provide a drawer slide of the second type ~i.e. one in
which the channels can be removed after assembly) has a
significantly longer life span.
The present invention in its broadest form
provides a retainer which has apertures which are
elliptical in shape when viewed from the side. The
apertures are formed such that when the ball i~ seated
for rotation between the retainer apertures and the outer
slide flange wall, the points of contact of the balls are
at the top and bottom of the apertures close to or at the
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~` 64635-32
axis of rotation, when the drawer exhibits longitudinal
movement. Thus the ball rotates about the vertical axis
during retainer travel. Unlike the present devices, the
balls do not contact the sides of the aperture where the
greatest velocity of the ball occurs.
In a preferred embodiment the apertures are
punched into the side flanges of the retainer in the form
of round holes which have radii larger than the balls for
which these are designed to retain. Thus in the first
stage of production tne balls are able to fall through
the apertures. However in a second phase of production
the upturned flanges are folded along the horizontal axis
at the approximate mid-point of the aperture between the
base and the top of the flange. Thus, an eliptical
opening is formed having a vertical axis which is less
than the horizontal axis. The ball lying in the pocket
has friction points at the top and the base of the
aperture. This is the area of lowe~t velocity during
rotation of the balls, therefore providing the least
resistence to ball rotation during movement of the drawer
slide channels.
After the fold the retainer in cross-section
has a flange which extends obliquely upwards and outwards
from the base to the mid-point of the aperture and then
obliquely upwards and inwards to the top of the flange.
Therefore this invention seeks to provide a
ball-bearing retainer for use with drawer slides
comprising a channel member consisting of a base and at
least one upturned side flange, said side flange having
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64635-32
at least one aperture; said aperture being elongated in the
length of the channel and further dimensioned to engage and
retain a common steel ball for longitudinal movement; and when
in operation said aperture provides a seat for rotation of said
steel ball about an axis which is transverse to the length of
the channel member and at right angles to the base thereof,
such that the regions of the ball most distanced from the axis
of rotation do not contact said aperture.
The invention is described in greater detail in
conjunction with the following drawings wherein:
Figure 1 is a perspective view of a prior art ball
retainer;
Figure 2 is an enlarged view of the pocket area of
the retainer shown in Figure 1;
Figure 3 is a perspective view of a preferred
embodiment of the present invention;
Figure 4 is an enlarged view of the pocket area of
the retainer shown in Figure 3;
Figure 5 is a face view of the pocket area after the
side flanges have been folded;
Figure 6 is an end view of a preferred embodiment of
the retainer of the present invention and
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64635-32
Figure 7 is an end view of the right side of a
three part drawer slide with the retainers of the present
invention in place.
In Figure 1 one see~ the prior art ball
retainer ~nown generally as (l). It has a base (2) and
upwardly turned side flanges (3). Each of ~ide flanges
(3) has an aperture punched therein and is marked as (4).
Each of the apertures are adapted to receive a ball (5).
In Figure 2 one sees an enlarged view of the
pocket area showing the flange (3) and the aperture (4).
Balls rotate about a vertical axis shown in dotted lines
as (6). The ~ide~ of the aperture (4) are slightly
depres~ed inwardly. The ball rests ~n the depre~sed
pocket area with its principal points of contact on the
edges of the aperture basically shown as (7) and (8).
When the ball turns about the vertical axis (6) during
longitudinal movement of the slide a portion of the ball
shown generally in a dotted area as (9) is the portion of
the ball which comes in contact with the edges of the
aperture (4) at points (7~ and (~). This portlon of the
ball shown as (93 is that which is furthest removed from
the vertical axis, and that which also has the greatest
velocity during movement thereby causing considerable
friction and resistence.
Figure 3 show~ an embodiment of the ball
retainer of the present invention which is generally
designated as (10). It has a base (11) and upturned side
flanges (12). A round aperture (13) is punched in each
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~4635-32
of the ~ide flanges (12). The side flanges are then
folded about a horizontal axis (14) at the approximate
mid-point of the aperture (13). The ball~ (15) are then
adapted to be seated for rotation within the aperture
(13) being retained between the flanges (12) and the
inside of the side flange of a outer slide channel (not
shown in Figure 3).
Figure 4 is an enlarged view of a side flange
of the retainer shown in Figure 3. As noted before, the
side flanges are folded about a horizontal axi~ (14)
thereby creating an eliptical aperture when viewed from
the ~ide. The axis of rotation for the ball (15) is
shown in a broken line and numbered (16). After folding
the flange the verticsl diameter of the aperture i~ less
than the horizontal diameter of the aperture and as such
the points of contact of the ball (15) are at the ba~e
and the top of the aperture shown respectively as numbers
(17) and (18) respectively. The contact portions of the
ball (15) are shown generally as (19) and (20). These
respectively come in contact with area~ (17) and (18) of
the aperture'~ ~ide~. It is to be noted that ~uch point~
are nearest the vertical axis of rotation and a~ such
they are the areas of lowe~t velocity during rotation of
the ball. By having these portions of the ball come in
contact the amount of friction during rotational movement
is minimized, therefore resulting in les~ wear.
Figure 5 i~ a fragmentary side elevation of the
upturned side flange~ (12) of the retainer generally
known a~ (10). The flanges are viewed after they have
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~ 64635-32
been folded along horizontal axes (14). After the folding
has occurred, the aperture (13) appears eliptical. One
notes that the diameter of the aperture between points
(21) and (22) on the horizontal axis is considerably
larger than the diameter between pointq (23) and (24) on
the vertical axis. Hypothetically, in a perfect world,
points (23) and (24) would repre~ent the points of
contact with the ball (15) (not shown in Figure 5).
Figure 6 is an end view of a preferred
embodiment of the retainer (10) of the present invention.
It has a base (11) and side flanges (12) which are folded
along the horizontal axes (14).
In Flgure 7 one sees the end view of the left
side of a three part slide employing ball retainers which
are the subject of the present invention. There is an
outer channel slide (25) having a curvilinear upturned
flange (26). A retainer (10) ha3 a base (11) and an
upturned side flange (12) which fits within the outer
channel slide flange. Balls (15) are placed within the
apertures of the retainer and seated between the flange
(12) and the inside of the outer slide channel
curvilinear outside flange (26). An intermediate channel
~lide (27) has both an upturned side flange (28)
and a downwardly extending flange (29). Within the
intermediate slide is a second retainer (10) having a
base (11) and upturned side flange (12). An inner slide
channel (30) having a downturned flange (31) fits over
the second retainer (10). A ball (15) is seated between
upturned flange (12) and the inner side of the upturned
flange (28) of the intermediate channel ~lide (27).
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64635-32
The balls are seated between both the intermediate slide
channel (27) and the outer slide channel (25)~ and the
intermediate slide channel (27) and the inner slide
channel (30). The balls al~o contact the raceways formed
by flanges (29) and (31) respectively.
In operation of the drawer slides, the balls
(15) turn about the vertical axes (16) having contact
points (17) and (18) of aperture ~13). The horizontal
circumerence of the ball during rotation contacts only
the slide channel flange raceways. The configuration
of the retainers of the present invention greatly
decreases wear and increases life of the balls, the
retainer~, and the channel slide members.
It is also to be noted that the present
invention is not restricted to the embodiments herein but
extends to any variation thereof which falls within the
spirit of the present invention.
