DRAWER INTERLOCK

Abstract: An interlock system for a filing cabinet or the like preventing any two drawers from being open at one time, the system using a generally vertical line of contacting balls (18) as a lock, and means on each drawer to rigidify the line of balls upon the opening of a single drawer, and returning the line of balls to a loose, unlocked condition upon closing the drawer.

Description: This invention relates to multiple drawer file cabinets having a lock system preventing moving any other drawer to open position when one only of the drawers is already open. Many file cabinets open to such an extent and hold such heavy material as to tend to and actually do tip over forwardly if more than a single drawer is open. This tilting may be injurious to the person and it is very desirable to avoid it. Interlocks have been suggested in the past, see U.S. Patents 4,429,930, February 7, 1984; 4,303,287, December 1, 1981; and 4,298,236, November 3, 1981 as examples of this art. NL-A-7604359 discloses an interlocking system comprising a string of single, whole discrete elements, receptor means to confine said elements in said string variously in a separable and movable condition and in a contiguous and immovable condition along said string, and a series of at least two actuators at selectable fixed positions along said string, each actuator having an interposing means arranged to be entered between two of said elements by movement of the actuator when at least some of the elements are movable, to prevent entrance between said elements by the interposing means of the other one or more actuators. FR-A-2173463 discloses a string of discrete elements having protruding pins for engagement by non-spherical interposing means; the string having a biassing spring at one end thereof. Such prior devices are not completely satisfactory as to operation, cost, and even noise, and an improved interlock device is presented in this case that is easier to install and smoother in operation, more positive in action. Other advantages will become more clear hereinafter. According to the present invention there is provided an interlocking system comprising a string of single, whole discrete elements, receptor means to confine said elements in said string variously in a separable and movable condition and in a contiguous and immovable condition along said string, a series of at least two actuators at selectable fixed positions along said string, each actuator having an interposing means arranged to be entered between two of said elements by movement of the actuator when at least some of the elements are movable, to prevent entrance between said elements by the interposing means of the other one or more actuators, wherein said actuator is pivotably attached to a plate which is disposed over the string of discrete elements each actuator having a discrete interposing means adjacent to the junction of two of said elements, said interposing means being spherical with a radius r and injectable between two of said elements for a distance of less than r , displacing said elements against at least one axially aligned spring at the distal end of the string, offsetting the junctions between the other elements from their respective adjacent interposing means. In particular, in a substantially conventional file cabinet, there is an operating device on each drawer such as a laterally extending fixed pin, and in a fixed position on the casing there is an oscillatable actuator, there being such an actuator for each drawer, each actuator being aligned with its pin. There is a projection on each actuator to engage (and disengage from) a vertical string, row or line of discrete elements, e.g. balls, on the casing. The motion of the drawer towards open position swings the actuator which is thereby caused to move its projection from an inoperative position to a position engaged at least partly between a pair of contiguous balls, etc., separating them and causing the entire string or line to become tightly interengaged. This in effect converts the row or line of balls from a loose, relaxed condition to a condition wherein they are tightly interengaged, in a tense condition that may be referred to as locked. The pin on the drawer then leaves the actuator as the drawer is more fully opened, and on return to closed position once again impinges on the oscillatable actuator, returning it and its projection to ball-free condition. When the balls are loose, free, or relaxed, any drawer may be opened as above; when the falls are tensed, tight, or locked, no further drawer can be opened, as the locked together balls are sufficient to prevent any further projection from entering the string of balls. Should two or more drawers be attempted to be opened simultaneously, all balls will be locked before even one drawer is opened, so no drawer is opened, so no drawer will open. Figure 1 is perspective view partly cut away showing the general relation of the locking system to an otherwise conventional file cabinet; Figure 2 is a view in elevation showing the locking system per se with a single drawer open; Figure 3 is an elevational view partly in section looking in the direction of arrow 3 in Figure 2; Figure 4 is a sectional view on line 4-4 of Figure 2; and Figure 5 is an enlarged diagrammatic view showing the relationship of the locking balls and the actuator ball. A generally conventional filing cabinet is shown in Figure 1, as having a rear wall 10, top wall 12, and side wall 14, with a series of drawers 15, of which there may be as many as required, but more than one. These drawers comprise a "stack" of drawers, and typically, tend to tip the cabinet forwardly should more than one drawer be pulled to open position. There is of course a support for each drawer comprising telescopically extendable slides, etc., but such structure is all old and well-known and need not be shown, but each drawer can be individually drawn to open position and closed as will be clear without such showing in this case. A vertical receptor, track, or the like 16, is mounted in vertical relation to one or both side walls 14 at the inner aspect thereof, facing the stack of drawers. Each such track contains a string, row, or line of small, discrete elements 18, resting one upon the next below to the extent necessary for them to correspond spacially with the number of drawers. The pertinent fact is that these elements do not quite fill the track vertically as will become clear hereinafter. However, the receptor or track 16 is open at the front, by reason of slot 20 which makes the elements 18 accessible from the front, i.e., at the side facing the drawers, but this slot is narrow enough to restrain the elements, as in their loose condition, to a vertical row or line. The elements 18 are "loose", because they do not quite completely fill the receptor or track, which acts as a tube in which they are held. For each drawer there is a plate 22 appropriately secured to the side wall 14 across the receptor track 16 by any means, such as screws 24, and these plates each provide a swivel mount for an actuator 26, as by means of a pivot pin 28, or the like on the plate. The actuator herein has a radial slot 30 defined by a longer arm 32 and spaced shorter arm 34 tangentially arranged as in Figure 2. Offset from the axis of the actuator is a ball 36, or similar spherical object, held in a conventient recess 37 in plate 22 and in actuator 26 as at 38, see Figures 3 and 5. Thus, with the actuator swung to the right or left, the ball 36 is forced thereby partly into slot 20, see Figure 5, and impinges upon elements 18 tending to separate them and thus effectively lock the entire string, line, or row of balls 18 into a fixed, tensed condition. In this situation, no other actuator can be turned sufficiently to cause its ball 36 to move any elements 18, i.e., the tensed, locked elements 18 will not move to accommodate any other ball 36 until such time as the open drawer is closed, and its actuator returns to position releasing the ball 36 so it is ineffective to lock elements 18. To facilitate this action, the sides or recess 38 are chamfered as shown in Figure 5, wherein the ball 36 is shown in dotted lines in its inwardmost projection into the line of elements 18, which illustrates the forcing of ball 36 in the line of balls. Ball 36 is forced out of the slot 20 by the actuator 26, to solid line position when the actuator returns to original, upright position. The receptor track 16 is equipped with a small spring 39 at at least one end to receive the last element 18 in the line under pressure from ball 36. Spring 39 will close to substantially solid condition, or expand under release of pressure to position the stack of elements 18. Also, another spring can be used at the other end of the line of elements if found to be desirable. Thus, but a single drawer may be opened at any one time and should two drawers be attempted to be opened together, they will cause interblockage of each other. In the drawings, a simple pin 40 fixed to each drawer at an appropriate spot works the actuator by entry into slot 30 as the drawer closes, pushing the actuator to upright position wherein ball 36 is free of elements 18. When the drawer is fully home, the pin 40 remains in slot 30, at or near the bottom thereof. As the drawer is moved toward open condition, the pin 40 moves the actuator to the right in Figure 2 for instance, and on out of slot 30, but leaving the actuator substantially fixed in position to once more receive the pin 40 on drawer closing motion, to be returned to upright position.

Claims: 1. An interlocking system comprising a string of single, whole discrete elements (18), receptor means (16) to confine said elements in said string (20) variously in a separable and movable condition and in a contiguous and immovable condition along said string, a series of at least two actuators (26) at selectable fixed positions along said string, each actuator having an interposing means (36) arranged to be entered between two of said elements by movement of the actuator when at least some of the elements are movable, to prevent entrance between said elements by the interposing means of the other one or more actuators, characterized in that, said actuator (26) is pivotably attached to a plate (22) which is disposed over the string of discrete elements (18) each actuator having a discrete interposing means (36) adjacent to the junction of two of said elements (18), said interposing means (36) being spherical with a radius r and injectable between two of said elements (18) for a distance of less than r (36 in phantom), displacing said elements against at least one axially aligned spring (39) at the distal end of the string (20), offsetting the junctions between the other elements from their respective adjacent interposing means. 2. The system of claim 1 characterized in that the discrete elements (18) are provided with curved surfaces to positively receive the respective interposing means (36) on each actuator (26). 3. The system of claim 1 or claim 2 and including a spring (39) at each end of the string (20). 4. The system of any preceding claim characterized in that each actuator (26) is oscillatable on a fixed axis (28) whereby said interposing means (36) is arranged to be entered between two of said discreet elements (18) by movement of said actuator.

Inventors: LAKSO, MATTHEW L.
Applicants: ENGINEERED SECURITY PRODUCTS CORPORATION
Application year: 1988
Main classification: E05B65
IPC codes: E05B65