Shock Absorbing Bracket for a Fallfront Cabinet

This invention relates to fallfront cabinets and particularly to such cabinets having shock absorbing means for the fallfront panel thereof.

In the fallfront cabinet and door-stop arts a number of different arrangements have been used for spring loading the folding or sliding supporting brackets for the fallfront panel or door, as shown, e.g., in U.S. Pat. Nos. 1,864,599; 2,013,418; 2,268,104; 2,565,442; 2,648,583; 2,674,511; 2,718,025; 2,910,336; 3,224,827; Netherlands No. 52339; and West Germany No. 761794. U.S. Pat. No. 2,718,025, for example, shows a flexible chain link between a door and its frame, the link being spring loaded at the midpoint by means of a tension spring running to the vicinity of the hinge portion of the door or frame.

This prior art device was designed for vertically mounted doors, and dangling of the flexible chain links and spring when the door is closed (FIG. 1) is of only slight disadvantage.

Such dangling of chain, however, would be intolerable in, e.g., a Sheraton secretaire such as the one illustrated on page 172 of "English Furniture and Decoration 1680 to 1800," G. M. Elwood, published by Julius Hoffman, Stuttgart MCMIX.

Less offensive but equally impractical would be the use of dangling chains in the cabinet of a modern magnetic tape transport, such as the one employing the present invention, which includes a fallfront panel for access to interiorally-mounted circuits.

Accordingly, it is an object of the present invention to provide shock-absorbing apparatus for a fallfront cabinet, which apparatus automatically conceals itself with the cabinet is closed.

A shock absorbing fallfront bracket of the type having rigid hinged-together links diagonally supporting the fallfront panel in its open position and folding into the cabinet in closed position, and also including a third spring loaded link extending from the mutual hinge of the linked pair and to the cabinet to resiliently resist the full opening of the panel, and to fold, when closed, fully into the cabinet along with the supporting linked pair.

FIG. 1 is a fragmentary left side cross-section elevation taken on the plane of arrows 1--1 of FIG. 2 showing the bracket of the present invention in open position; and

FIG. 2 is a fragmentary front elevation of the apparatus shown in FIG. 1; and

FIG. 3 is a fragmentary front elevation of the apparatus shown in FIGS. 1 and 2 in closed position.

Referring now to the drawing and particularly to FIGS. 1 and 2 thereof, there is shown the left side of a fallfront cabinet 11 including a fallfront panel 12 hinged to the cabinet at the lower edges as by hinges 13, and supported in the open position as by rigid links 14, 16 hinged together as by a spring loaded pin 17 and at adjacent ends the other end of upper link 14 being hinged to the cabinet as by a hinge pin 18 extending from a mounting bracket 19 that is affixed to the cabinet by bolts 21; and the lower link 16 being hinged to the panel 12 as by a hinge pin 22 extending from a side edge portion of the panel. In the present cabinet a pair of such link arrangements are employed, the other being applied to the right side of the cabinet.

It will be seen that in the above arrangement, the links when fully opened would describe the hypotenuse of a 45-degree right triangle, the hypotenuse being a dimension 2L, the dimension "L" being the length of each link 14, 16; and the hinge pins 18, 22 being spaced from the 90-degree apex by a dimension 1.414L. Consequently, there is a space below the closed position of the hinge pin 17 (as illustrated in phantom in FIG. 1 and in solid in FIG. 3) for the positioning of a third hinge pin 23 extending from the cabinet.

The third hinge pin 23 serves to pivot a third rigid link 24, which has a longitudinal slot 26 in which hinge pin 17 runs freely so as to define a sliding hinge connection to the link assembly 14, 16 at their mutual hinged portions. Thus, as the cabinet is closed, link 24 folds along with links 14, 16 to a concealed position illustrated in FIG. 3.

To absorb the final shock of opening panel 12, the link 24 is provided with a tension spring 31 looped at one end around an ear 32 at the lower end of slot 26, and at the other end around hinge pin 23; and the link is also formed with a second slot 33 in which hinge pin 23 slides. Thus, when the panel 12 is substantially but not fully opened (e.g. about 88.5 degrees), the spring 31 may be distorted to absorb the final shock of opening, and the panel 12 (after opening to some angle greater than 88.5 degrees but not greater than 90 degrees), returns to the static open position illustrated at about 88.5 degrees.

It has been found that the panel weight in the environment of the present invention is 14.0 lbs. It is estimated that the if the assembly is allowed to fall open without restraint and is then abruptly stopped with the panel horizontal, this weight would be increased by 10 G's and would represent 140 lbs. For a reasonable mounting position of the assembly as shown in FIG. 1 the actual increased weight would be 228 lbs. or 114 lbs. per side based on the system including two sets of links. The proper placement of link 24 would bring into engagement an energy absorbing spring 0.5 inch before links 14, 16 fall into a straight line to create a solid stop, and this 114 pound force can be held at equilibrium with only a 12.8 lb. spring force. If the spring were engaged only 0.125 inches from the stop, the equilibrium force would be reduced to only 3.2 lbs. However, to truly reduce G forces, the mechanism must stop over some reasonable distance. Due to space limitations and the need for a reasonable size energy absorbing spring with safe working stresses, the braking distance of 0.5 inch was selected, and accommodated by means of the slot 33.