Supports: cabinet structure – With movable components – Horizontally movable
Reexamination Certificate
2001-05-07
2004-04-13
Wilkens, Janet M. (Department: 3637)
Supports: cabinet structure
With movable components
Horizontally movable
C312S333000, C312S334110
Reexamination Certificate
active
06719386
ABSTRACT:
FIELD OF THE INVENTION
The field of the invention is drawer suspension systems. More particularly, the field of the invention relates to precision drawer slides for mounting drawers in a carcass.
BACKGROUND OF THE INVENTION
Drawer suspension systems are used in numerous applications ranging from residential furniture, office furniture, institutional furniture, and in other applications such as toolboxes, cash registers, and photo copying machines, to name a few.
The basic configuration of a drawer suspension system relies on a first part, which may comprise a metal channel member, that is mountable to the side wall of a carcass, and a second part which may comprise a metal channel member that is mountable to a drawer, with means provided in-between the first part and the second part for allowing travel such that the drawer may be moved from a closed position to an open position and vice-versa. There are distinctions that are made between the types of products that serve to function as part of a drawer suspension system, with two member roller slides occupying the lighter duty requirements such as kitchen cabinets, while mid-range and higher duty requirements are handled by three membered slides and the group as a whole is known as “precision” drawer slides. Many of these are typified by the usage of ball bearing assemblies for translational movement.
Many examples of precision drawer slides are known in the art, including U.S. Pat. No. 6,033,047, (Hoffman), U.S. Pat. No. 5,466,060, (Hoffman) and U.S. Pat. No. 4,469,384, (Fler). Typically, precision drawer slides are characterized by the usage of ball bearings to provide the inter connection between the channel members and to provide for translational movement between the members. Precision drawer slides include particular design approaches such as those where the members telescope, one inside the other, or where the members may be positioned one over the other vertically and are linked by an interconnecting plate, or where various members may be “ganged” in a back-to-back treatment. The design characteristic that is selected is dependent in part on the particular application to which the slide is being directed, or the type of loading that will be anticipated to be encountered once in use.
In addition to the foregoing, there are other considerations in precision drawer slide technology. The selection between the types of drawer slide movement may be preferentially drawn towards a sequential acting drawer slide or a progressive acting drawer slide. In the former, the members of a telescoping type precision slide, for instance, can be made to open in a very selective manner, such that the cabinet member, which typically remains fixed, supports an intermediate member (or center member) and a drawer member both of which substantially “nest” into the envelope of the cabinet member profile. The drawer member is attached to the drawer, carrying the drawer and its contents. When a precision drawer slide of this type is opened in a sequentially acting version, the intermediate member and the drawer member move forward in unison, owing to the particular sequential engagement device involved, until the center member reaches the end of its forward travel. At that point, the drawer member is then released from the sequential engagement device and is allowed to continue the forward travel until it reaches its end. In this fashion, the loading efficiency is maximized as between the points on the drawer member and the intermediate member during the early stages in the opening of the drawer. In the forward most position, it can be appreciated that the load is substantially cantilevered over the outward most points of the drawer slide travel reducing the spreading of the load since it is asserted over a smaller contact zone as between the drawer member contact with the intermediate member, and similarly, with the intermediate member contact with the cabinet member. The actual transmission of the loading occurs normally through the ball bearings until the load is received by the cabinet member. In the sequential action described, it is believed that the ball bearings in the cabinet races actually operate under conditions of less pressure as the slide is opened since the loads are not cantilevered as they would be in other slide designs. When sequential action is used, the load is distributed across more portions of the drawer member and the intermediate member in the early stages of the opening procedure which is beneficial to the performance and durability of the drawer slide.
In the alternative, a progression type movement is known whereby, using the same example cited above, the intermediate member and the drawer member are made to move simultaneously in the forward direction. The advantage of this progressive movement is that the load capacities are still being dispersed efficiently, to a large extent (although not as completely as they are in the sequential acting drawer slide). Even though the forward end of travel for both the intermediate member and the drawer member are reached at pretty much at the same point in time, the actual speed at which each member travels is not the same. Typically the drawer member has to travel its full length before it reaches the fully opened position while the intermediate member travels approximately about half its length. This results in the drawer member being progressively moved at about twice the speed at which the intermediate member travels.
One clear advantage of the progression type of movement is the fact that it is actuated by frictional engagement with a rolling surface in the usual mode. This circumvents the traditional noise that is incurred in the sequential acting drawer slides which is caused by the sequential engagement mechanism (typical a latching device) as the intermediate member and drawer member engage and release and engage and release during the operation of drawer opening and closing. It should be apparent and realized that in both circumstances, the sequential acting drawer slides and the progression action type drawer slides that the reverse phenomena happens with respect to the functioning of each type movement during the closing process.
Lastly, random action is probably the most prevalent means by which telescoping precision slides operate. In this mode, there is no functional assistance to dictate the sequence or progression of member actuation. It basically occurs as a consequence of the forces applied to the drawer when opened, which are transmitted in a serendipitous manner to the slide elements. In most cases, the drawer member is opened first, with the center member proceeding thereafter as a matter of being urged open by contact with the drawer member and/or ball bearing retainer. The actual modality for the opening procedure in a random action slide will vary as the particular slide design, the age of the slide, the load being carried, and as the name implies.
In both the random action and sequential action type of telescoping slides it is known that the contact between the members, and/or the ball bearing retainer, will result in undesirable noise and the transmission of the contact impact as for example, the center member is picked up by the drawer member during opening, or when the center member impacts the cabinet member which may occur prior to the time when the drawer member reaches it full extension.
Turning now to other aspects of precision drawer slide technology, there has been a long standing design approach with respect to the configuration of the channel members that make up the precision drawer slide product itself. The channel members, as the name implies, are roughly “C-Shaped” and the height and width of the various components of the web and flanges making up the member may vary with the application, the load that is anticipated, and the design envelope that may be available to the manufacturer. With respect to precision drawer slide members; it is believed that the prior art relies on only two basic types of members to achieve the desired functions
Knape & Vogt Manufacturing Co.
Van Dyke Gardner, Linn & Burkhart, LLP
Wilkens Janet M.
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