U.S. patent number 3,799,638 [Application Number 05/281,421] was granted by the patent office on 1974-03-26 for drawer interlock.
This patent grant is currently assigned to Steelcase, Inc.. Invention is credited to Frederick S. Faiks.
United States Patent |
3,799,638 |
Faiks |
March 26, 1974 |
DRAWER INTERLOCK
Abstract
A drawer interlock employs a ribbon stop member positioned on
the inside of a cabinet and extending along the cabinet in a slack
fashion adjacent a plurality of cam members positioned on the
cabinet to be actuated by an associated catch member positioned on
each of a plurality of drawers. As a drawer is extended from the
cabinet, the camming member associated with the drawer is rotated
to allow the passage of the catch thereby, while simultaneously
engaging the ribbon to take up the slack in the ribbon such that no
additional cams can fully rotate to allow the opening of associated
drawers. When the drawer is closed, the drawer catch rotates the
cam as it passes returning the stop member to the slack condition
so that another or the same drawer can be opened.
Inventors: |
Faiks; Frederick S. (Comstock
Park, MI) |
Assignee: |
Steelcase, Inc. (Grand Rapids,
MI)
|
Family
ID: |
23077226 |
Appl.
No.: |
05/281,421 |
Filed: |
August 17, 1972 |
Current U.S.
Class: |
312/216;
312/333 |
Current CPC
Class: |
A47B
88/70 (20170101); E05B 65/466 (20130101) |
Current International
Class: |
A47B
88/00 (20060101); A47B 88/02 (20060101); E05B
65/46 (20060101); E05B 65/44 (20060101); E05b
065/46 () |
Field of
Search: |
;312/215,216,222,211,219,218,333
;292/99,102,146,182,198,203,216 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1,175,151 |
|
Dec 1969 |
|
GB |
|
1,903,282 |
|
Jul 1970 |
|
DT |
|
Primary Examiner: Gilliam; Paul R.
Attorney, Agent or Firm: Price, Heneveld, Huizenga &
Cooper
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows.
1. In a cabinet having at least two drawers, a drawer interlock for
preventing the simultaneous opening of two drawers comprising:
a cam operably connected to the cabinet adjacent each drawer, said
cam being movable between first and second positions and including
at least a first cam arm extending therefrom into the path followed
by an engaging means on a drawer when the drawer is opened;
engaging means on each of said drawers for engaging said first cam
arm of said cam and for moving said cam from said first position to
said second position as a drawer is opened, said engaging means
disengaging said cam as said cam reaches said second position
whereby said drawer is free to pass by said cam and open;
stop means mounted on said cabinet adjacent all of said cams, said
stop means being movable between first and second positions,
without itself effecting movement of other cams, when engaged by
any one of said cams, each of said cams being blocked from movement
from its said first position into its said second position when
said stop means is in its said second position; said stop means in
said second position being movable only back to said first position
thereby preventing more than one of said cams being moved to their
said second positions at any one time whereby only one drawer and
engaging means can be moved past an associated cam and opened at
any one time.
2. The drawer interlock as defined in claim 1 wherein said cam
comprises an eccentric cam rotatably positioned on the cabinet.
3. The drawer interlock as defined in claim 2 wherein said cam
includes a second cam arm which moves into the line of travel of
said engaging means after said engaging means has disengaged said
cam as a drawer is opened whereby as the drawer is closed, said
engaging means engages said second arm to rotate said cam in a
direction toward said first position.
4. The drawer interlock as defined in claim 3 wherein said cam
engaging means includes first and second spaced cam-engaging
members wherein said first cam-engaging member engages said first
cam arm to rotate said cam from said first to second positions as a
drawer is opened and said second cam arm as a drawer is closed to
partially rotate said cam from said second to first positions, and
said second cam engaging member engages said first cam arm to
complete the rotation of said cam to said first position as a
drawer is closed.
5. The drawer interlock as defined in claim 1 wherein said engaging
means comprises a drawer catch including at least three cam
engaging surfaces and said cam includes a second cam arm extending
therefrom in spaced relationshp whereby one of said cam engaging
surfaces contacts said first cam arm as a drawer is opened to
rotate said cam to said second position, and whereby a second cam
engaging surface contacts said second cam arm to partially rotate
said cam in a direction toward said first position as a drawer is
partially closed, and a third cam engaging surface contacts said
first cam arm to finally rotate said cam into said first position
as a drawer is closed.
6. The drawer interlock as defined in claim 5 wherein said cam
further includes a spring arm extending therefrom and means fixedly
positioned on the cabinet to engage said spring arm such that
during installation of a drawer into the cabinet, said cam is
rotated by said second cam engaging surface pushing against said
first cam arm until said spring arm contacts said means fixed on
the cabinet, and as the drawer is moved to a closed position, said
second cam engaging surface clears said first cam arm and said
spring arm rotates said cam in an opposite direction such that said
first cam arm is captured between said first and third cam engaging
surfaces.
7. A drawer interlock mechanism for cabinets and the like having a
plurality of drawers, said mechanism comprising:
a flexible stop means mounted on a cabinet between two fixed points
adjacent a plurality of drawers, said flexible stop means being
movable between slack and taut positions;
a cam means movably mounted to a cabinet adjacent each drawer and
adjacent said stop member;
cooperating means on said cam and said drawer cooperating to move
said cam means into said flexible stop means when a drawer is moved
from a closed position in the cabinet; said flexible stop means
being dimensioned such that movement of one of said cam means into
said flexible stop means takes up the slack in said flexible stop
means and said flexible stop means restricts movement of additional
cam means causing said cooperating means to act as a stop
preventing movement of an additional drawer therepast.
8. The drawer interlock as defined in claim 7 wherein said
cooperating means comprises a cam arm extending from said cam
means, and a cam engaging member positioned on a drawer to engage
said cam arm as a drawer is moved between closed and open
positions.
9. The drawer interlock as defined in claim 7 wherein said cam
means is movable by the opening of a drawer from a first position
in which said stop member is slack, to a second position in which
said cam means deflects said stop member into a taut position and
during the motion of said cam means from said first to second
positions, said cam arm moves to allow said cam engaging member to
clear said cam arm permitting the opening of said drawer.
10. The drawer interlock as defined in claim 9 wherein said cam
means is eccentric and rotatably positioned in a cabinet and is
rotated by the movement of said cam engaging member.
11. In a cabinet having at least two drawers, a drawer interlock
for preventing the simultaneous opening of two drawers
comprising:
a flexible ribbon positioned between two fixed points on the
cabinet;
a catch positioned on each drawer; and
a cam operably positioned on the cabinet adjacent each drawer and
adjacent said ribbon; said cam being movable between first and
second positions, said cam engaging said flexible ribbon and taking
up slack in said flexible ribbon between said fixed points when in
said second position; said cam and said catch including first
cooperating means which engage as a drawer is opened to move said
cam from said first to said second position; said first cooperating
means disengaging when said cam reaches said second position to
allow said drawer catch and drawer to pass by said cam; said
flexible ribbon having sufficient slack between said two fixed
points to allow one and only one of said cams to be moved into said
second position whereby only one drawer in the cabinet can be
opened at a time.
12. The drawer interlock as defined in claim 11 wherein said cam
comprises an eccentric cam rotatably positioned on the cabinet and
wherein said first cooperating means comprises a first cam arm
extending from said cam and a first cam arm-engaging member on said
catch to selectively contact said cam arm.
13. The drawer interlock as defined in claim 12 wherein said cam
includes a second cam arm which moves into the line of travel of
said first cam engaging member after said first cam engaging member
has disengaged said cam as a drawer is opened whereby as the drawer
is closed, said first cam engaging member engages said second arm
to rotate said cam in a direction toward said first position.
14. The drawer interlock as defined in claim 13 wherein said catch
includes a second cam-engaging member wherein said first
cam-engaging member engages said first cam arm to rotate said cam
from said first to second positions as a drawer is opened and said
second cam arm as a drawer is closed to partially rotate said cam
from said second to first positions, and said second cam engaging
member engages said first cam arm to complete the rotation of said
cam to said first position as a drawer is closed.
15. The drawer interlock as defined in claim 14 and further
including guide means adjacent each cam and constraining said
ribbon on either side of each of said cams whereby movement of said
ribbon by said cam is localized deflection of said ribbon.
16. The drawer interlock as defined in claim 15 wherein said guide
means comprises a bracket segmented into ribbon guiding channels
between which are positioned a plurality of cam mounting
locations.
17. The drawer interlock as defined in claim 11 wherein said drawer
catch includes at least three cam-engaging surfaces and said cam is
rotatably positioned on the cabinet and includes two cam arms
extending therefrom in spaced relationship whereby one of said
cam-engaging surfaces contacts a first one of said cam arms as a
drawer is opened to rotate said cam to said second position, and
whereby a second cam-engaging surface contacts a second one of said
cam arms to partially rotate said cam in a direction toward said
first position as a drawer is partially closed, and a third
cam-engaging surface contacts said first one of said cam arms to
finally rotate said cam into said first position as a drawer is
closed.
18. The drawer interlock as defined in claim 17 wherein said cam
further includes a spring arm extending therefrom and means fixedly
positioned on the cabinet to engage said spring arm such that
during installation of a drawer into the cabinet, said cam is
rotated by said second cam-engaging surface pushing against said
first cam arm until said spring arm contacts said means fixed on
the cabinet, and as the drawer is moved in a closed position, said
second cam-engaging surface clears said fist cam arm and said
spring arm rotates said cam in an opposite direction such that said
first cam arm is captured between said first and third cam-engaging
surfaces.
19. The drawer interlock as defined in claim 15 wherein said cam
includes a cam surface which progressively deflects said ribbon as
said cam is rotated and a ribbon guide integrally formed therewith
for holding said ribbon in alignment with said cam as it is
rotated.
20. The drawer interlock as defined in claim 19 and further
including guide means positioned on the cabinet for permitting only
a section of said ribbon to be deflected by the movement of a
drawer.
21. The drawer interlock as defined in claim 11 wherein said ribbon
includes take-up means to control the slack in said ribbon.
22. The drawer interlock as defined in claim 21 wherein said
take-up means comprises a loop integrally formed in said
ribbon.
23. The drawer interlock as defined in claim 21 wherein said
take-up means comprises a leaf spring anchored at one end to said
bracket and extending into biased contact with said ribbon.
24. The drawer interlock as defined in claim 21 wherein said ribbon
is positioned in the cabinet in a generally straight line and is
deflected in a direction generally perpendicular to the length of
said ribbon.
25. The drawer interlock as defined in claim 16 wherein said
bracket includes ribbon supporting lands extending from an edge of
each channel into said cam mounting locations in the direction of
deflection of said ribbon by said cam.
26. The drawer interlock as defined in claim 25 wherein each cam
mounting location of said mounting bracket includes a detent, and
wherein each of said cams includes a deflectable detent engaging
member to contact said detent when said cam is in said second
position to insure said cam remains in said second position until
the associated drawer is closed.
Description
BACKGROUND OF THE INVENTION
The present invention relates to drawer interlocks for preventing
the opening of more than one drawer of a cabinet at a time.
In cabinets having a plurality of drawers and particularly
relatively narrow and high cabinets such as file cabinets which may
contain heavy items in each of the drawers, it is desired to
prevent more than one drawer from being fully extended at one time.
If two or more drawers are opened, it is possible that the cabinet
could topple over. Some prior art interlock systems employ a
rotatable rod extending vertically in the cabinet and coupled to a
spring-loaded engaging mechanism. When a drawer is opened, the rod
rotates and locks the remaining drawers in a closed position. Some
systems employ a rope or wire which is interconnected to each of
the drawers and has sufficient slack to permit the full extension
of one of the drawers but will not allow the remaining drawers to
be extended.
Although some of these systems perform adequately, they do not
prevent the simultaneous opening of two drawers. Even the rope type
allows two drawers to be partially opened simultaneously. Some
prior art systems are relatively complex and, therefore, costly to
manufacture. Others lack the durability necessary for cabinets
which are frequently used.
SUMMARY OF THE INVENTION
The apparatus of the present invention, however, prevents even the
simultaneous opening of two drawers and employs a mechanism which
can be fitted within a cabinet and on the drawers thereof to
provide a durable yet inexpensive system for preventing the opening
of more than one drawer. The apparatus can be installed as an
integral part of new cabinets or can be added to many existing
cabinets. With the present system, a cam can easily be removed from
the mounting bracket for replacement or repositioning by simply
removing the drawer. This allows a great degree of flexibility in
modular file cabinet construction where a variety of drawer
positions are available for use.
The drawer interlock of the present invention employs a single stop
member extending between two or more drawer levels and which
interacts with camming means actuated by a catch positioned on a
drawer to move the stop from a slack position which permits the
opening of a drawer to a taut position which prevents the opening
of a second drawer.
Apparatus embodying the present invention includes a catch
positioned on each drawer of a cabinet having two or more drawers,
and camming means positioned on the wall of the cabinet in
alignment with each drawer catch to be engaged thereby as a drawer
is opened or closed. Stop means is positioned on the cabinet to
extend across each of the camming means and has a slack position
which permits one of the camming means to rotate and permit the
passage of a drawer catch thereby while simultaneously engaging the
stop to take up the slack thereby preventing additional camming
means from rotating to permit the passage of a second drawer
thereby.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary side elevational view of the portion of the
apparatus of the present invention adapted to be positioned on a
cabinet having two or more drawers;
FIG. 2 is a cross section of a portion of the apparatus shown in
FIG. 1 taken along plane II--II in FIG. 1;
FIG. 3 is a fragmentary side elevational view showing one of the
cam members shown in FIG. 1 taken from the side opposite that shown
in FIG. 1 and showing the relationship of the member to a drawer
catch with the drawer illustrated in a closed position;
FIG. 4 is a side elevational view of the apparatus shown in FIG. 3
with the drawer shown in the process of being opened;
FIG. 5 is a side elevational view of the apparatus shown in FIG. 4
showing the drawer in the process of being closed;
FIG. 6 is a side elevational view of the apparatus shown in FIGS. 3
through 5 during the initial installation of a drawer;
FIG. 7 is a front elevation view of the camming means;
FIG. 8 is a fragmentary side elevational view of one embodiment of
the stop member;
FIG. 9 is a fragmentary side elevational view of an alternative
embodiment of the stop member;
FIG. 10 is a side elevational view of an alternative arrangement
for mounting cam members and the stop member to a wall of a
cabinet;
FIG. 11 is a plan view of the cam member mounting bracket shown in
FIG. 10; and
FIG. 12 is a plan view of the stop member mounting bracket shown in
FIG. 10 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the preferred embodiment, the drawer interlock includes a stop
ribbon 30 mounted vertically in a segmented guide 20 which in turn
is secured to the inside wall 10 of a cabinet or the like.
Rotatably mounted in the open space 13 between adjacent segments of
guide 20 are a plurality of cams 40. When a drawer 60 is opened, a
catch 62 thereon engages cam 40 and passes thereby. As catch 62
passes, it rotates cam 40 to the position of cam 40b shown in FIG.
1. This takes up all available slack in ribbon 30 and prevents
other drawers 60 from opening. Each cam 40 and catch 62 are
designed to cooperate in such a way that if one attempts to open
two drawers simultaneously, all of the slack in ribbon 30 is taken
up before either catch 62 is free to pass by its cam 40.
In the embodiment shown in FIG. 1, guide 20 is formed integrally
with a cabinet reinforcing and drawer suspension mounting bracket
12. Bracket 12 is vertically mounted to the wall 10 of the cabinet
near the front thereof by means of a plurality of mounting screws
or bolts 14 extending from one of the convoluted walls of the
bracket into the side wall of the cabinet or by spot welding. The
bracket 12 includes a plurality of apertures 16 and flanges 18
which are conveniently formed in the bracket for supporting drawer
suspending members for the file cabinet but form no part of the
present invention.
Bracket 12 further includes a wall portion 11 with guide 20
comprising a guide wall 22 extending outwardly from wall 11 and
having an overturned edge or lip 24 as seen in FIG. 2. Guide 20
guidably supports a stop ribbon 30 extending longitudinally along
the guide 20. Guide 20 is segmented to include a plurality of open
spaces 13 between adjacent guide segments and being positioned at
each possible drawer level location. The guide wall 22 of guide
member 20 is inwardly bent to form a land 25 on each side of each
open space 13 which, when the stop ribbon 30 is deflected inwardly,
provides a smooth ribbon support area. Integrally formed with wall
11 of the mounting bracket are a plurality of tabs 26 which are
positioned generally centrally within the open space 13 of the
guide wall 22 and include raised areas 28 having an aperture
therein (not shown) for supporting cam means 40 in spaced
relationship from the inside wall 10 of the cabinet. Adjacent
raised areas are raised detents 15 which insure that a cam 40 will
stay in its "drawer open" position (cam 40b) when rotated thereby
by its associated drawer catch 62 (FIG. 1).
Stop ribbon 30 comprises a ribbon 31 of flexible highly stretch
resistant material such as ribbon steel or other suitable material.
One embodiment of the stop ribbon is shown separately and in detail
in FIG. 8. As seen in FIG. 8, hooks 32 are positioned at opposite
ends of the ribbon 31 and are secured to ribbon 31 by means of a
crimping connection 34. Ribbon 31 has a take-up loop 35 formed
therein to take up the slack of ribbon 31 when all of the drawers
60 are closed. Take-up loop 35 is flexible, however, and permits,
as described below, the stop ribbon 30 to be deflected around a
camming member 40 to take up the slack and pull stop member 30 taut
when one of the drawers of the file cabinet is opened. As seen in
FIG. 1, the hooks 32 are positioned over opposite ends of guide 20
which provide fixed mounting points for the stop ribbon 30.
FIG. 9 illustrates an alternative embodiment of the stop ribbon 30
like the FIG. 8 embodiment but employing a leaf spring 36 which is
fixedly positioned to the bracket at an end 36' adjacent the ribbon
31 and extending into contact with the ribbon to deflect the ribbon
to take up the slack. The leaf spring is selected to have a spring
constant which will permit the movement of one of the camming
members 40 to take up the ribbon 30 and in so doing, deflect the
spring. The spring can be fitted in one of the unused cam spaces 13
in bracket 12.
The cam member 40 can be molded from a suitable polymeric material
such as polyvinyl chloride, polyethylene or like moldable material.
Each cam member 40 comprises a center sleeve 42 having an aperture
therein adapted to receive a mounting screw 41 or the like which
rotatably mounts cam member 40 to raised area 28 of bracket 12
(FIGS. 1, 3 and 7). As best seen in FIGS. 3 and 7, each of the cams
further includes a spring arm 44 extending tangentially from the
sleeve 42 and including a right angled tip 45 thereon. Spring arm
44 acts as a cam return during installation of a drawer 60 as will
be hereinafter explained.
The cam member 40 additionally includes a support wall 46 extending
from approximately the middle of sleeve 42 and at right angles to
the axis of the sleeve. Supported orthogonally around the
peripheral edge of wall 46 by means of a plurality of ribs 48
(shown only in FIGS. 4 and 5 for clarity) is a generally curved lip
50. Lip 50 includes three stop member engaging surfaces 51, 52 and
53 which are integrally formed at obtuse angles relative to the
adjacent engaging surface. The junctions of surfaces 51, 52 and 53
are generally rounded and the junction of surfaces 52 and 53 is
spaced somewhat farther from the axis of rotation of cam 40 than is
the junction of surfaces 51 and 52 to form an eccentric cam.
Surface 51 extends tangentially from sleeve 42 approximately
opposite spring arm 44 (FIG. 3). Surfaces 51, 52 and 53 are shaped
to permit easy deflection of the ribbon for drawer operation and to
prevent the cam from returning to the position 40a (FIG. 1) when
tension is applied to the ribbon by another drawer.
Lip 50 includes ribbon guides 54 and 54a projecting outwardly from
the junction of surfaces 51 and 52 as seen in FIG. 7. Guide 54
includes a stand-off tip 55. The guides 54 and 54a hold ribbon stop
31 in alignment with the surfaces 51, 52 and 53 of cam 40 and are
spaced from the side of bracket 12 such that the ribbon is freely
deflectable when cam 40 is rotated as described below.
Extending from sleeve 42 along an edge of support wall 46 is a
first cam arm 47 which is a flat rectangular member extending from
the middle of sleeve 42 outwardly in a direction opposite lip 50
(FIGS. 1, 3 and 4). Arm 47 has a rounded tip 49 as best seen in
FIGS. 1 and 3. A second cam arm 58 having a rounded tip 59 extends
radially outwardly from the sleeve 42 as seen in FIG. 3. Cam arms
58 and 47 are spaced from each other by approximately 80.degree. in
the embodiment shown, although with different drawer catches, this
spacing may be varied. This spacing should be such that the two cam
arms 58 and 47 act in conjunction with catch 62 to provide for
smooth, even rotation of cam 40 through an arc greater than
90.degree. when drawer 60 is closed. The closing action should
begin with the engagement of arm 58 and proceed until the angle of
arm 47 with respect ot catch 62 is less steep, at which point
engagement of arm 47 should finish the closing. Likewise, spring
arm 44 is spaced approximately 45.degree. from cam arm 58 in the
preferred embodiment. Again, this spacing can be varied somewhat
and is not critical except to the extent that it must insure that
cam 40 will be sprung into its neutral, drawer closed position
during drawer installation.
On the left side of each drawer 60 of the cabinet and positioned
slightly below the axis of each cam member 40, as shown in FIG. 3,
is a drawer catch 62 comprising three generally vertical walls 64,
66 and 68. These act as cam engaging surfaces extending outwardly
from the side of the drawer. An angled surface 65 couples walls 64
and 66 and a rear wall 67 joins walls 66 and 68. Catch 62 is
attached to one side of the drawers by suitable fastening bolts
through wall 67 or, in the embodiment shown where the drawers are
steel, is spot welded to the drawer. By providing a catch of this
configuration for each drawer, a plurality of cam engaging surfaces
are provided which cooperate with cam 40 to smoothly rotate the
associated cam 40 as the drawer is opened and closed.
Middle wall 66 provides the cam engaging surface which engages cam
arm 47 to rotate cam 40 to its open position (FIG. 4). Front wall
68 extends just a little higher than the middle wall 66 to insure
that it will engage cam arm 47 as the drawer is closed thereby
insuring rotation of cam 40 back to its neutral position. To insure
that rotation back to the neutral position is smooth, the third cam
engaging surface, wall 64, is spaced behind wall 66 and engages the
second cam arm 58 to initiate rotation. Once cam 40 reaches a
certain point, front wall 68 insures complete return of cam 40 by
engaging cam arm 47. Actually, wall 65 can be considered part of
the rear cam engaging surface since it is the juncture of walls 64
and 66 which does most of the engaging of cam arm 58.
OPERATION
Referring now to FIGS. 3 through 6 for a detailed discussion of the
operation of the interlock, it is noted initially taht the cam 40
has two "at rest" positions, one of which is the neutral position
illustrated in FIG. 3 with the associated drawer closed. In the
neutral position, the first cam arm 47 is positioned between
camming engaging walls 66 and 68 of the drawer catch 62. The other
"at rest" position is the inverted or drawer open position
illustrated in FIG. 1 (cam member 40b ) in which the cam is rotated
approximately 120.degree. to take up the slack in the stop ribbon
30. The cam is progressively moved between these positions by the
opening and closing of the drawer and the interaction between the
cam engaging walls of the drawer catch and the cam arms of cam
40.
With the drawer closed, the slack stop member 30 is guidably
positioned between ribbon guides 54 and 54a of the member 40, and
cam arm 47 is positioned between walls 66 and 68 of catch 62 (FIG.
3). As the drawer is opened, as illustrated in FIG. 4, the drawer
and catch 62 move in a direction indicated by arrow B and cam
engaging wall 66 initially contacts the left side (in FIG. 4) of
cam arm 47 causing the cam member 40 to rotate in a
counterclockwise direction. This rotation causes the lip 50 to
engage ribbon 31 and the curved junctions of surfaces 51, 52 and 53
thereof (which are progressively spaced from the center of rotation
of cam 40) take up slack in the stop ribbon 31 smoothly. As the
drawer continues its outward motion, catch 62 will cause the cam to
rotate sufficiently counterclockwise that as the apex of the cam
engaging surface 65 clears the end of first cam arm 47, ribbon 31
will rest against the cam and hold the cam member in its inverted
position maintaining the stop member 30 under tension. This results
since the net reactive force of the taut ribbon 31 against cam 40
is directed above the center of rotation of the cam member. Detent
15 in bracket 12 also acts as insurance against cam 40 rotating
inadvertently back to its drawer closed position, because stand-off
tip 55 has to ride over detent 15 in order to move cam 40 between
its two rest positions. The detent has a tapered leading edge
which, as tip 55 reaches the detent, tends to snap the cam into the
drawer open position (40b in FIG. 1).
With the stop ribbon 30 held in the taut position, if a second
drawer is pulled outwardly, the cam 40 associated therewith is
restricted from rotating since the taut stop member 30 will not
yield to permit rotation of the cam. The relatively elongated
leading surface 51 of lip 50 will contact the taut stop member and
prevent the movement of catch 62, since cam engaging wall 66
contacts the arm 47 of the blocked cam. Likewise, if one attempts
to open two drawers simultaneously, the combined partial rotation
of two cam members associated therewith will cause the stop member
30 to become taut. This, in turn, prevents further rotation of
either of the cam members sufficiently to allow drawer catch 62 to
clear cam arm 47.
As an opened drawer is closed in a direction indicated by arrow A
in FIG. 5, wall 64 on drawer catch 62 contacts cam arm 58 to begin
the clockwise rotation of the cam member 40. As the drawer is more
completely closed, wall 68 of drawer catch 62 contacts cam arm 47
of cam member 40 to complete the clockwise rotation of the cam back
to its neutral position as the drawer is fully closed. This dual
interaction of cam arm 58 with cam engaging wall 64 and cam arm 47
with cam engaging wall 68 produces smooth operation of the cam when
the drawer is closed.
Installation of drawers 60 can be effected automatically regardless
of what position an associated cam 40 is in. This installation is
best understood by referring to FIG. 6 where it is seen that the
cam is in the neutral or downward position and a drawer 60 is being
initially inserted into the cabinet such that its associated catch
62 is in an engaging position with the cam 40 for that catch. It is
desired to position the cam arm 47 between the cam engaging walls
66 and 68 of catch 62 as seen in FIG. 3. This is accomplished by
the angled cam engaging surface 65 which, as the drawer is closed
(moving in a direction indicated by arrow A), contacts the cam arm
47 as shown in FIG. 6.
As the drawer closes, the engaging surface defined by wall 64 and
surface 65 rotates cam 40 in a clockwise direction such that the
tab 45 of spring arm 44 contacts the guide wall 22 and deflects to
provide spring tension against which the cam is rotated. As soon as
the cam arm 47 clears the apex of surface 65, the spring action of
arm 44 will snap cam 40 in a counterclockwise direction until the
cam arm 47 strikes cam engaging wall 68 of catch 62 thereby
capturing arm 47 between walls 66 and 68. The drawer catch is
positioned on the drawer and the bracket holding the cam members 40
on the file cabinet such that this occurs at approximately the
closed position of drawer 60.
In place of mounting the cam member on wall 11 integrally formed
with guide member 20 and bracket 12 as shown in FIGS. 1 and 2, cam
member 40 and the stop ribbon 30 can be separately attached to a
mounting bracket 70, shown in FIG. 10, by means of a separate cam
mounting bracket 80 and stop ribbon mounting bracket 90. As seen in
FIGS. 10 and 13, the stop ribbon bracket 90 includes upper and
lower walls 91 and 92 which include integrally formed U-shaped
guide members 94 along outer edges thereof and which include
inwardly directed guiding lands 95 which span an open area between
walls 91 and 92. The bracket additionally includes an integral
L-shaped section 96 joined to walls 91 and 92 for mounting the
bracket to a raised ridge 72 on bracket 70. Member 96 has a flange
97 which fits within the apertures 74 of bracket 70 and an aperture
98 which permits a mounting screw 99 to be attached
therethrough.
Bracket 80 shown in FIG. 11 is a generally Z-shaped bracket having
a mounting leg 82 with an aperture 83 therein that is aligned with
aperture 98 in bracket 90 when bracket 80 is fitted over bracket 90
as seen in FIG. 10. Bracket 80 includes a second leg 86 with an
inwardly directed post 84 positioned thereon to hold cam member 40
by extending through the aperture in sleeve 42 of the cam member.
This positions the cam in the central open area between guides 94
of bracket 90 such that the ribbon 31 is engaged by the rotatable
cam in the same manner as discussed above.
It will be apparent to those skilled in the art that various
modifications to the present invention can be made. For example,
the cam design and guiding means for the stop member, as well as
the mounting means for the cam and the stop member, can be varied
without departing from the spirit of the present invention as
defined in the appended claims.
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