Cabinet interlock mechanism

Abstract

The invention provides a mechanism for interlocking the pull-out drawers or shelves of a storage cabinet so that when a specified drawer or shelf is pulled out, the remaining drawers or shelves are interlocked in a closed or retracted position. The invention constitutes an improvement over the invention of U.S. Pat. No. 3,404,929 in that it permits the arrangement and number of drawers or shelves in a cabinet to be varied without having to replace the interlock bar.

Description

This invention relates to the interlocking of selected moveable units of a storage system, and more particularly to the interlocking of drawers and other pull-out components of a storage cabinet.

BACKGROUND OF THE INVENTION

It is often desirable to prevent selected moveable units of a system from moving independently of one another. Such is the case where a specified storage unit, e.g., a drawer or pull-out shelf, of a filing cabinet has been pulled out. The remaining units of the cabinet are desirably interlocked in a closed or retracted position, so as to prevent them from being pulled out and thereby interfering with access to the specified unit or causing the cabinet to tip over and spill its contents and possibly injure the user of bystanders.

U.S. Pat. No. 3,404,929, issued 10/8/68 to David M. Wright and Carl J. Dean for Interlocking of Selected Units of a Storage System discloses an interlock mechanism for storage cabinets which employs a slidable vertically extending locking bar that spans a plurality of storage units and cooperates with cam assemblies mounted on each storage unit to effect the desired interlocking. The lock bar has a plurality of locking pins, one for each storage unit, and the cam assemblies of the several units are proportioned to engage the associated locking pin on the locking bar. When a specified storage unit is pulled out, its cam assembly engages the corresponding locking pin and thereby cams the locking bar so that the cam assemblies of the other storage units are blocked by the other locking pins, whereby these other storage units are held locked until the specified storage unit is restored to its normal retracted position. The mechanism also is designed to protect against accidental release of the interlocked mechanism.

Although the above-described prior art interlock mechanism is simple and effective, it has a severe limitation. It happens that many users of storage cabinets with multiple pull-out storage units have unique or special requirements with respect to the number, type and size of pull-out components. Fabrication of an interlock for each different arrangement of pull-out component requested by customers involves provision of many different locking pin arrangements. This is expensive and time consuming and contrary to mass production principles. Furthermore, many users desire that the cabinets be so designed as to permit them to easily change the spacing between and the relative positions of the pull-out components, and even to permit installation of additional components. However, the interlock mechanism disclosed in U.S. Pat. No. 3,404,929 employs locking pins that are fixed to the locking bar. Hence, repositioning of drawers or other pull-out components by the user may result in a locking pin being in a position relative to a pull-out component that prevents effective operation of the interlock system.

Accordingly, the primary object of this invention is to provide an interlock mechanism for pull-out components of a storage cabinet that overcomes the above-described limitation of the mechanism disclosed in U.S. Pat. No. 3,404,929.

Another object of the invention is to provide an improved interlock system of the type described which is adapted to accommodate different arrangements of pull-out and fixed storage components without having to employ different lock bars and is adjustable to preserve effective interlock operation when the arrangements of storage components is changed by the user.

Still a further object is to provide an interlock mechanism of the type described which is adapted for use in cabinets with vertically adjustable pull-out storage units.

A more specific object is to provide an interlock system for multi-component storage cabinets which has the same advantages but improves upon the mechanism disclosed in U.S. Pat. No. 3,404,929.

Other objects of the invention are rendered obvious by the description which follows.

SUMMARY OF THE INVENTION

The interlock mechanism of this invention comprises at least one locking bar assembly which is slidably disposed along one side of the cabinet and spans one or more vertically displaced pull-out storage components. The locking bar assembly comprises a slidable locking bar and one or more locking pin sub-assemblies according to the number of pull-out storage components to be interlocked. Each locking pin sub-assembly is adapted to be shifted lengthwise of the locking bar and comprises a locking pin and means for releasably locking the locking pin to the locking bar in a selected position for interaction with a storage component. Each pull-out storage component includes a cam assembly which is disposed for interaction with a corresponding locking pin. Each cam assembly is designed so that when the associated storage unit is withdrawn, i.e., pulled out, the cam assembly engages the corresponding locking pin and cams the locking bar vertically to a position in which the cam assemblies of the other pull-out units are blocked by the other locking pins, whereby the other units are locked in their retracted or closed positions until the withdrawn unit is restored to its retracted or closed position. Other features, aspects and advantages of the invention are disclosed in or rendered obvious by the following detailed description taken in conjunction with the drawings.

THE DRAWINGS

FIG. 1 is a perspective view, with a certain part broken away, of a multi-shelf storage cabinet embodying a preferred form of interlock mechanism constructed in accordance with the invention;

FIG. 2 is a sectional view in side elevation on an enlarged scale of the cabinet of FIG. 1;

FIG. 3 is a fragmentary exploded perspective view showing one of the side suspension units associated with a pull-out component;

FIG. 4 is a fragmentary perspective view showing a side suspension unit engaged with the locking bar assembly;

FIG. 5 is an enlargement of a sectional view taken along line 5--5 of FIG. 2;

FIG. 6 is a fragmentary plan view, with a part broken away, of a locking bar assembly;

FIG. 7 is a view in side elevation of a locking bar and the detent element that is affixed to its upper end;

FIG. 8 is a perspective view of one of the locking pin sub-assemblies; and

FIG. 9 is a side elevation of a cam assembly.

Turning to the drawings, FIG. 1 illustrates a file cabinet 2 which incorporates an interlock mechanism constructed in accordance with the present invention. The cabinet 2 consists of a top wall 4, opposite side walls 6 and 8, a rear wall 10 (FIG. 2), a bottom wall 11 (FIG. 2), and a front base panel 12 which are interconnected to form an integral structure. Side panels 6 and 8 have right angle flanges 13 at their front ends. The cabinet also includes a self-storing door which in this case is in the form of a tambour 14 and made up of a plurality of interlocked and hinged slats 15 (FIG. 2) and a handle bar 16. In FIG. 1 the tambour is in its open or stored position. The cabinet comprises a tier of pull-out shelves 17. For convenience of illustration, only two shelves 17 are illustrated in FIG. 1. However, it is to be appreciated that additional shelves may be accomodated by the cabinet. Also, although not shown, it is to be understood that the pull-out shelves may be replaced by pull-out drawers. Each pull-out shelf is mounted on a pair of conventional suspension arm units which are identified generally in FIG. 1 by the numeral 18. The cabinet also includes an interlock mechanism identified generally by the numeral 20 which is illustrated in greater detail in the other figures of the drawing.

Referring now to FIGS. 1 and 2, the tambour 14 is guided at its side edges so that it can be raised or lowered so as to reveal or conceal the pull-out shelves. In FIG. 2, the tambour 14 is shown in its closed position. The construction of the tambour 14 and the means for guiding it form no part of the present invention; nevertheless, certain details of the guide means for the tambour are described hereinafter in order to facilitate understanding of the present invention.

Referring now to FIG. 2, an outer track member is mounted to side wall 8. This track member comprises an upper horizontal section or run 19A and front and rear vertical sections or runs 19B and 19C respectively. This track member is of angle iron, i.e., L-shaped, cross-section, with one angle portion 21 being parallel to the side wall and the other angle portion 22 extending at right angles to the side wall and acting as an outer guide or track for the tambour. An inner top-track assembly 24 also is mounted to the side wall. The track assembly 24 comprises a plate 26 with a right angle flange 28. The latter extends parallel to the portion 22 of the horizontal outer track section 19A and acts as an inner or lower top guide or track for the tambour 14. Also attached to side wall 8 are two upright members 30 and 32. These two uprights are essentially channel members, consisting of body portions 34 which are spaced from the adjacent side wall, plus opposite side wall portion 35 having flanges 37 which are secured to the side wall. The angle portions 21 of the outer track member sections 19B and 19C overlap and are affixed to the flanges 37 of the front and rear side wall portions of uprights 30 and 32 respectively as shown in FIGS. 2 and 3. The front side wall portion of the front upright 30 acts as an inner front guide or track for the right hand edge of tambour 14, while the rear side wall portion of the rear upright 32 acts as an inner rear guide for the same tambour edge. Thus the right hand edge of the tambour 14 rides between and is guided by the portions 22 of the outer track sections 19A-C, and the flange 20 of the inner top track assembly and the front and rear side wall portions respectively of uprights 30 and 32 as it is raised or lowered. The inner top track assembly 24 also includes a sprocket 38 which is rotatively mounted to its plate 26 and engages interlocking portions of the tambour slats 15. The rear end of track assembly 24 also comprises a rear guide 40 attached to plate 26 which acts as a transition between flange 28 and the rear side wall portion of rear upwright 32. Sprocket 38 and guide 40 assure that the tambour will not bind as it is raised and lowered.

Although side wall 6 is not shown in the same detail as side wall 8, it is to be understood that it is provided with a corresponding arrangement of track sections 19A-C, track assembly 24 and uprights 30 and 32 as shown in FIG. 2, with the result that the left-hand edge of tabmour 14 is guided in the same way as the right hand edge.

The uprights 30 and 32 on each of the walls 6 and 8 are provided with a series of vertically spaced horizontally elongated slots 42. These slots serve to position the suspensions for the various pull-out shelves. Referring now to FIG. 3, each of the pull-out shelves 17 comprise a rear wall 44, a bottom wall 45, and opposite side walls 46. Although not shown, it is to be understood that each side wall of the shelf is attached to a suspension arm unit 18. For this purpose each side wall 46 is provided with a pair of hook-like mounting tabs 48 which are punched out of the side walls. Each of the two suspensions 18 for each of the pull-out drawers comprises three telescoping arms 50, 52 and 54 with the arm 50 having a pair of slots 56 (only one of which is visible in FIG. 3) to accommodate tabs 48. The tabs interlock with arm 50 so that shelf 17 can move with arm 50 as the latter telescopes relative to arms 52 and 54. As shown in FIG. 5, the arms 50, 52 and 54 are slidably connected by ball bearings 57. Each suspension arm 54 is provided with two pairs of mounting tabs 60 (FIG. 3) for interlocking with pairs of slots 42 in uprights 30 and 32. The tabs 60 are hook-shaped and after they are inserted in selected one of the slots 42, the suspension arm 54 is shoved rearwardly so that the tabs will interlock with the uprights 30 and 32. Then, while arms 50-54 are extended as shown in FIG. 3, a sheet metal retaining screw 62 engaged in a hole (not shown) in arm 54 is screwed up so that it engages the rear flange of the front upright 30, thereby locking suspension arm 54 against movement relative to the upright and the adjacent side wall.

It is to be understood that the suspension arms shown in the drawing are of conventional design and suspension arms of other known design may be used to mount the shelves for pull-out action. In any event, each pull-out shelf is supported by a first suspension arm assembly attached to the uprights on cabinet side wall 8 and a second suspension arm assembly attached in a similar manner to the uprights on the opposite cabinet side wall 6. Obviously, the height of each of the pull-out shelves can be adjusted by raising or lowering the suspension arm assemblies with respect to the uprights 30 and 32 at each side of the cabinet. This permits a variable number of pull-out shelves or drawers to be mounted in the cabinet, and also the use of pull-out shelves or drawers of different vertical dimensions.

Referring now to FIGS. 1, 3, 5 and 9, the interlock mechanism includes like cam assemblies associated with each pull-out shelf which cooperate with pins on the locking bar assembly hereinafter described. The cam assemblies employed in the preferred embodiment of the invention and illustrated in the drawings are substantially the same as the ones illustrated and described in said U.S. Pat. No. 3,404,929. Each cam assembly consists of an upper cam member 64 and a lower cam member 66. The upper cam member has two intersecting ramp surfaces 68 and 70 and an end surface 72. The lower cam member has oppositely sloping ramp surfaces 74 and 76 separated by a horizontal surface 78. The cam members are spaced apart so as to define a channel 80 between surfaces 70 and 74 that is wide enough to allow movement therethrough of a locking pin as the associated shelf is pulled-out and pushed back again to its closed position. These cam members are attached to the pull-out shelf on the side wall adjacent to the locking bar assembly, and are located above the level of the associated suspension arm unit. They may be made of metal or various other materials such as those mentioned in said U.S. Pat. No. 3,404,929.

Referring now to FIGS. 2 and 4, the illustrated preferred embodiment of the interlock mechanism comprises a locking bar guide in the form of a U-shaped vertically extending channel member 84 that is affixed to cabinet side panel 8 between uprights 30 and 32 but adjacent to upright 30. Slidably disposed in the open vertical channel defined by channel member 84 is a slidable locking bar assembly that comprises an elongate locking bar 86 in the form of a flat C-shaped channel member. More particularly, locking bar 86 consists of a flat body portion 88 and parallel flat opposite side walls 90 that extend at right angles to body portion 88 and have integral right-angle flanges 92. Locking bar 86 and its guide 84 are sized so that the former makes a close sliding fit in the latter and so that the front surfaces of flanges 92 are at least flush and preferably project beyond the front edges of the sides of guide 84. The locking bar may be retained in guide channel member 84 by slidable retaining means, e.g., straps attached to the sides of the channel member and extending across and in front of the locking bar, located at the upper and lower ends of the guide member. However, such retaining means are not absolutely required since the upper end of the locking bar is engaged with a detent means hereinafter described and the remainder of the locking bar is slidably retained at various points by engagement of the suspension arm units that are attached to the adjacent side wall of the cabinet with the locking pin sub-assemblies hereinafter described. Nevertheless, to hold the locking bar in channel member 84 in the absence of any suspension arm units, it is preferred to provide a retainer in the form of a flexible L-shaped bracket 95 which is secured to cabinet bottom wall 11 and extends up inside of and lightly engages the bottom end of the locking bar.

The locking bar assembly also includes a plurality of locking pin sub-assemblies 94 carried by locking bar 86. One locking pin sub-assembly is provided for each pull-out shelf. Referring now to FIGS. 2, 4, 5 and 8, each locking pin subassembly 94 comprises a spacer plate 96 which is made up of a flat rectangular body portion 98, an offset portion 100 and an inclined flange portion 102. Spacer plate 96 may be made of plastic but preferably is made of sheet metal. In any event it is made of a fairly stiff yet resilient material so that its offset and flange portions can yield without breaking or undergoing permanent deformation when engaged by a suspension arm unit as hereinafter described. The body portion 98 is formed with four projections 104, one near each of its four corners, which are similar in shape to a section of a sphere and thus have straight edges as shown. Where the spacer plate is made of metal, the projections are formed by pushing out semi-circular portions of the spacer body. In any event, projections 104 function as locator or guide means to maintain the spacer plate so that its opposite side edges 106 (FIG. 8) extend parallel to side walls 90 of locking bar 86. To this end, the projections are located so that they will fit between flanges 92 and so that their straight side edges will slidably engage the adjacent edges of flanges 92. The body portion of each spacer plate also is formed with a centrally located circular boss 108 (FIG. 5) which projects oppositely to projections 104 and has a center hole.

Each locking pin sub-assembly 94 also comprises a lock pin or stud 110 which is formed with a hexagonal shaped flange 112 and a threaded extension 114. The lock pin is mounted to the spacer plate by inserting its threaded extension 114 through the hole in boss 108 so that the latter is engaged by flange 112, and then screwing onto extension 114 a nut 116. As seen best in FIG. 8, nut 116 is elongated in one dimension so as to have straight opposite sides 118, and has a thickness less than the gap between each of the flanges 92 and body portion 88 of locking bar 86. Additionally, the distance between its straight sides 118 is less and the length of each of said sides is greater than the gap between the confronting edges of locking bar flanges 92. As a result, the nut can be easily inserted between the flanges 92 if it is oriented so that its straight sides extend lengthwise of the locking bar, and can be retained by the same flanges if it is oriented so that its straight sides extend at an oblique angle to the confronting edges of flanges 92. The straight sides of nut 116 are made long enough so that the side walls 90 of the locking bar will limit its rotation to less than 180.degree.. Preferably the nut is sized so that side walls 90 prevent it from assuming an angle of greater than about 45.degree. relative to the longitudinal axis of the locking bar. Assuming that the locking pin sub-assembly is mounted to the locking bar in the manner described and illustrated, it can be locked in any desired position merely by orienting nut 116 so that it extends behind flanges 92 and then rotating the locking pin conveniently by applying a wrench or pliers to hex flange 112 so as to advance its threaded portion in a direction to cause the nut and spacer plate to tightly engage flanges 92. To change the position of the spacer plate along the lock bar, all that is required is to loosen the nut, then slide the spacer to the desired position, and finally retighten the nut. Preferably but not necessarily, the end of the threaded extension 114 may be peened or swaged over so as to form a head or flange which will prevent it from pulling out of the nut when unscrewing the lock pin to release the spacer plate.

Of course, for each pull-out shelf a certain positioned relationship must be maintained between the locking pin and the cams associated with the adjacent side of the shelf, otherwise, the desired interlocking operation will not be achieved. Since the location of the cams is fixed with respect to the associated suspension unit, it is a relatively easy matter to locate each locking pin sub-assembly at the specific height required for it to correctly engage the cams of a designated pull-out shelf. This adjustment is accomplished using the gauge template 120 (FIG. 4) which has a channel portion 122 adapted to snugly embrace the rear suspension arm 54 and an upstanding lip or flange 124. With the gauge template in place, the lock pin sub-assembly is lowered on locking bar 86 until its lock pin is resting on lip 124. Then the lock nut is tightened and the gauge template is removed. By properly proportioning the height of lip 124, the lock pin assembly will be in the correct position for interaction with the cams of the associated pull-out shelf when lock pin 110 is moved against lip 124 of the gauge template.

The locking bar is movable vertically between two predetermined DOWN and UP positions which are determined by a detent mechanism consisting of cooperating members carried by the locking bar and inner top track assembly 24. Referring now to FIGS. 2 and 5, a plastic wear plate 130 is attached to the upper end of locking bar 86, the latter being provided with an aperture into which a portion of the wear plate is secured. The front side of the wear plate is provided with two offset surface portions 132 and 134 that are connected by a sloping surface portion 136. The upper offset surface portion 132 is provided with two rounded, preferably circularly curved, grooves or sockets 138. Affixed to plate 26 of track assembly 24 is a hollow member 140 that is open at one end and is closed off at the opposite end by an end wall 142. The latter has an air exhaust port 143. Hollow member 140 projects through a hole in plate 26 and has an exterior flange 144 that is affixed to plate 26 by screws 146 (FIG. 2). Slidably mounted within hollow member l40 is a hollow detent member 148 which is formed with a rounded ball-like extension 150 sized to mate with grooves 138. A compression spring 151 within member 140 urges detent member 148 into engagement with wear plate 130. In normal operation of the interlock mechanism, locking bar 86 moves between a lower or DOWN position (FIG. 5) in which detent member 150 is seated in the upper one of grooves 138 and a higher or UP position in which member 150 is seated in the lower groove. In each of these positions the bottom end of the locking bar is restrained against moving out of guide channel member 84 by bracket 95. If it is desired to remove locking bar 86 from guide channel member 84, the locking bar is pushed up manually far enough for the detent member to be forced back by surface 134 of the wear plate and when this occurs the bottom end of the locking bar will have cleared bracket 95. Thereafter the lower end of the locking bar is pulled out of guide member 84 far enough so that it will not engage bracket 95 when it is subsequently lowered. Then the locking bar is pulled down far enough to disengage wear plate 130 from detent member 150, whereupon the locking bar can be pulled fully free of guide channel member 84.

Operation of the interlock mechanism will now be described. When all of the pull-out shelves 17 are in a closed position, as shown in FIG. 1, the locking bar is normally in its lower or DOWN position. When a selected shelf is withdrawn, the ramp surface 74 engages the adjacent locking pin 110 and thereby cams the locking bar to its UP position where it is held by the seating action of detent 150 on the lower groove 138. With the locking bar in its Up position, each of the other locking pins 110 is disposed in front of the front surface 72 of the upper cam member of the associated shelf. Consequently, the other shelves are blocked by their associated locking pins so that none may be pulled out inadvertently to cause the cabinet to tip.

When the withdrawn (i.e, pulled-out) shelf is returned to its closed (i.e., retracted) position, the cam surface 70 of its upper cam member will engage the associated locking pin and thereby cam the locking bar back to its initial DOWN position.

If the locking bar should inadvertently fall from its UP position when one of the shelves is pulled out, the cam surface 76 of the lower cam member of the withdrawn shelf will reengage the associated locking pin as the shelf is pushed back, thereby raising the locking bar and allowing the locking pin to travel along surface 78 which guides it into channel 80, whereupon the ramp surface 70 will again force the locking bar back to its DOWN position in the same manner as it would have if the locking bar had not fallen inadvertently while the shelf was pulled out.

The bevel ramp surface 68 at the front of each upper cam provides some latitude in locating the associated locking pin.

The snap action that characterizes the detent mechanism for the locking bar is important since when the latter is in its DOWN position, a substantial pulling force is required to pull out one of the shelves. Hence the locking pins and the ramps 74 of the several lower cam members coact to hold the shelves in their retracted positions until a pulling force is exerted on one of the shelves great enough to force the locking bar to overcome the hold-down force resulting from the coaction of the upper socket of the wear plate and detent member 150 under the influence of spring 151.

Although not shown, it is contemplated that the cabinet may be made with a keyed lock by which the shelves, drawers and other pull-out components, may be sured in a locked position. The key lock mechanism may be of the form described and shown in said U.S. Pat. No. 3,404,929; that is, it may include a rotatable crank which interacts with suitable bracket means on the locking bar to shift the latter up and down and lock it in its UP position so that the several locking pins 110 block the pull-out components and thus prevent them from being pulled out. Of course, other forms of key lock mechanisms also may be employed to perform the same function.

It is contemplated also that the cabinet may embody two interlock mechanisms as herein described, one at each side of the tier of shelves or drawers.

Persons skilled in the art will appreciate that the apparatus as herein described and illustrated may be modified in various ways, such as by changing the shape and arrangement of parts or by substituting equivalent elements, without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. In a filing cabinet containing at least two pull-out storage components, apparatus for maintaining prescribed ones of said components in retracted position when a selected one of said components is pulled out to an extended position, comprising:

a slidable locking bar assembly spanning said pull-out components, said locking bar assembly comprising a locking bar, at least two locking pins, one for each of said pull-out components, and lock means releasably securing said locking pins to said locking bar, said locking pins being moveable lengthwise of said locking bar when said lock means are released, said locking pins projecting laterally of said locking bar into adjacent relation with said pull-out components, and

cam means mounted on each of said pull-out components in position to engage the adjacent locking pin, said cam means each comprising a first portion for engaging and camming the adjacent locking pin so as to move said locking bar in a first direction from a first unlocking position to a second locking position when the pull-out component on which said cam means is mounted is pulled out to an open position, and a second portion for engaging said adjacent locking pin so as to prevent the pulling out of the pull-out component on which said cam means is mounted when said locking bar has been moved to said second locking position by the camming

2. Apparatus according to claim 1 wherein said cam means each comprises a third portion for (1) engaging said adjacent locking pin when said locking bar is in said second locking position and the pull-out component on which said cam means is mounted is in a pulled-out position and (2) camming said adjacent locking pin so as to move said locking bar in a second direction to said first unlocking position when the pull-out component on which it

3. Apparatus according to claim 1 further including means for maintaining

4. Apparatus according to claim 1 comprising a guide means for said locking bar, telescoping suspension arms attached to said cabinet and supporting said pull-out components, and spacer means slidably restrained by said suspension arms for holding said locking bar in slidable engagement with

5. Apparatus according to claim 4 wherein said spacer means is integral with said lock means for releasably securing said locking pins to said

6. Apparatus according to claim 1 wherein said locking pins each has a threaded extension; and further wherein said lock means for securing said locking pins to said locking bar each comprises a locking plate engaging one surface of said locking bar and having a hole through which said threaded extension protrudes, and a nut screwed onto said threaded

7. Apparatus in accordance with claim 2 wherein said cam means includes a fourth portion for (1) engaging said adjacent locking pin when said locking bar is inadvertently in said first unlocking position and the respective pull-out component on which said cam means is mounted is in a pulled-out position and (2) camming said adjacent locking pin so as to move said locking bar in said first direction to said second locking position before said third portion engages and cams said adjacent locking pin so as to move said locking bar to said first unlocking position.