Patent Application
20070252416
The present invention relates generally collapsible frame structures, and more particularly to collapsible frame structures comprising a plurality of separable frame members held together by an internal cord or cable.
Collapsible frame structures comprising a plurality of frame members that are joined end-to-end and held together by a flexible cord or cable are known. For example, U.S. Pat. Nos. 6,557,572; 4,827,958; 4,706,696 disclose tent poles comprising pole sections held together by an elastic cord. The individual pole sections can be separated and folded over to form a compact bundle for storage. The elastic cord pulls the individual frame members together to facilitate assembly. Similar frame systems may be found in other types of devices as shown by U.S. Pat. Nos. 6,038,802 (portable displays); 4,215,877 (folding utility carts); and 6,062,648 (folding chairs). Frame structures that rely on an elastic cord to hold the individual sections together are easily assembled but limited in the loads that can be supported.
It is also known to use an inelastic cable, such as a steel cable, to tension a multi-part frame structure as shown in U.S. Pat. Nos. 5,930,971 and 4,167,354. In these patents, a tension cable runs interiorly through individual frame members joined end-to-end and is tightened by means of a tensioning device after the frame is assembled to strengthen the frame. Frames that use an inelastic tension cable can support greater loads, but are not as easily assembled. Further, the tensioning devices tend to be cumbersome to operate.
Accordingly, there is a need for a collapsible frame structure that can support relatively heavy loads, and yet remain easy to assemble.
The present invention relates to a collapsible support frame comprising a plurality of frame members that are pivotally connected and held together by a flexible member. In one embodiment, the flexible member comprises a non-elastic cable to interconnect the plurality of frame members, which may be segmented. Portions of the non-elastic cable extends interiorly through the plurality of frame members. However, a portion of the non-elastic cable also extends exteriorly to the plurality of frame members. In one embodiment, the non-elastic cable exits the interior of a first frame member through an opening in a sidewall formed in the first frame member, and re-enters the interior of a second frame member through a corresponding opening in a sidewall formed in a second frame member. The openings are formed in their respective sidewalls such that they are spaced away from a pivot connection that pivotally connects the first frame member to the second frame member.
In another embodiment, the collapsible support frame comprises a first frame structure and a second frame structure. Each frame structure includes a first and a second pivotally connected frame member. A locking mechanism is configured to pivotally connect the first and second frame members of each frame structure. The locking mechanism permits a user to lock the collapsible support frame in an unfolded position, and to unlock the collapsible support frame to facilitate folding.
FIGS. 11A-B illustrate a frame structure according to another embodiment of the present invention.
Referring now to the drawings,
Frame structure 10 comprises a pair of pivotally connected frame members 12, 14 that are movable between an open position (
One or more flexible members, such as tension cable 18, hold the frame segments 12a-c, 14a-c together. The tension cable 18 is a flexible and generally non-elastic cable, such as a flexible polyester braided cord, or steel or carbon fiber cable, that is tensioned when the frame members 12, 14 are unfolded. Tension cable 18 imparts added strength to the frame structure 10 that may be needed for load bearing structures. When folded or collapsed, the tension cable 18 holds the frame segments 12a-c, 14a-c loosely together to prevent them from becoming separated and lost.
In one exemplary embodiment, tension cable 18 extends both interiorly through each frame segment 12a-c, 14a-c and exteriorly to the frame members 12, 14. To accommodate the tension cable 18 exiting and re-entering the frame members 12, 14, the sidewalls of each of the two uppermost frame segments 12a, 14a include an opening 20. The openings 20 are formed such that they generally face each other and are spaced from the pivot member 16. This allows the tension cable 18 to bridge or span the open area or gap between frame members 12, 14.
Because tension cable 18 is a generally flexible and non-elastic cable, it slackens whenever frame members 12, 14 are folded (
To control the slacked tension cable 18 and prevent it from snagging other objects, a slack control member 22 connects the tension cable 18 to a point of the frame structure 10. The slack control member 22 may be, for example, a biasing member such as a spring, or an elastic bungee cord that loops around the portion of tension cable 18 that spans the gap between the frame members 12, 14. The elasticity of the slack control member 22 allows it to stretch when the frame structure 10 is assembled (
The frame structure 10 may comprise part of a larger collapsible support frame.
Each frame member 104, 106, 110, 112 comprises multiple segments that join in end-to-end fashion and are separable from one another. Similarly, cross members 114, 116 and bracing member 118 comprise multiple segments joined in end-to-end fashion that are separable from one another. In this embodiment, frame members 104, 110 include 3 segments each denoted by reference numbers 104a-c and 110a-c respectively. Frame members 106, 112 comprises 3 segments each denoted by reference numbers 106a-c and 112a-c respectively. Cross members 114, 116 comprise 3 segments each denoted by reference numbers 114a-c and 116a-c respectively. Bracing member 118 comprises 2 segments 118a, 118b. As seen in
Frame member 104 and cross member 114 comprise a first frame structure 10 as shown in
Frame member 110 and cross member 116 form a second frame structure 10. A second tension cable 128 has a first end anchored in frame member 110 and a second end anchored in cross member 116. Beginning with the first end, tension cable 128 passes interiorly through frame segments 110a-c of frame member 110, exits frame member 110 through an opening 132 in frame segment 110a, enters cross member 116 through an opening 130 in segment 116a, passes interiorly through segments 116a-c of cross member 116, and terminates at a second end anchored in segment 116c. When the chair is unfolded, slack is removed from the tension cable 128 such that the tension on the tension cable 128 holds together the individual segments of frame member 110 and cross member 116. When the chair is folded, the tension cable 128 holds together the individual segments of frame member 110 and cross member 116. When the chair is folded, the tension cable 128 slackens allowing the individual frame segments of frame member 110 and cross member 116 to be separated.
In addition, a third tension cable 134 has first and second ends anchored in frame member 104 and 106. Beginning with the first end, tension cable 134 passes interiorly through frame segment 104c of frame member 104, exits frame member 104 through an opening 136 in frame segment 104c, enters frame member 106 through an opening 138 in segment 106b, passes interiorly through segments 106b-c of cross member 106, and terminates at a second end anchored in segment 106c.
A fourth tension cable 140 follows a similar path interiorly through and exterior to frame members 110, 112. Tension cable 140 passes interiorly through frame segment 110c of frame member 110, exits frame member 110 through an opening 142 in frame segment 110c, enters frame member 112 through an opening 144 in segment 112b, passes interiorly through segments 112b-c of cross member 112, and terminates at a second end anchored in segment 112c.
As above, slack is removed from the tension cables 134, 140 when the chair is unfolded such that the tension on the tension cables 134, 140 holds together the individual segments of their respective frame members 104, 106, 110, 112. When the chair is folded, the tension cables 134, 140 slacken to allow the individual frame segments of frame members 104, 106, 110, 112 to be separated.
In
The bracing member 118 comprises two segments 118a, 118b which are joined together in end-to-end fashion by an elastic cord 150. As best seen in
A sleeve 152 slidingly engages the segments 118a, 118b to maintain the segments 118a, 118b in an end-to-end relationship when the chair is unfolded. Sleeve 152 prevents the segments 118a, 118b from inadvertently separating when it covers the joint between the segments, and allows the segments 118a, 118b to fold freely when it does not cover the joint between the segments. A biasing member 154 such as a coil spring biases the sleeve 152 to cover the joint when the chair is unfolded. A pair of end caps 156 may be fixedly attached to each segment 118a, 118b to limit the sliding movement of the sleeve 152.
As previously stated, the frame members 114, 116 are pivotably connected to facilitate folding and unfolding the support frame 100. In the embodiment of
The detent 172 is integrally formed with the body 164 and comprises an arcuate surface that is slightly raised from a surface of the housing 164. The stop 174 is also integrally formed with the body 164 and extends away from the body 164. The detent 172 and the stop 174 are spaced from each other by a distance that is approximately equal to a diameter of one of the offset sections 114b, 116b. The detent 172 maintains the offset segment 114b within the space between the detent 172 and the stop 174 to lock the support frame 100 in the unfolded position. To unlock the locking mechanism 162, the user applies a force sufficient with which to move the segment 114b past the detent 174. This causes the frame members 114, 116 to pivot towards each other and allows the chair to be folded.
Returning to
In the previous embodiments, only the tension cables 122, 128, 134, 140 are used to tension the support frame 100. In other embodiments, such as the embodiment of
The previous embodiments illustrate the slack control members as looping around a portion of the tension cables that extends exteriorly to the frame members. In other embodiments, such as the one shown in
In this embodiment, frame structure 10 comprises an elastic slack control member 178, a floating connection device 180 that moves interiorly through frame member 12, and a stop 182 to limit the movement of the floating connection device 180. The floating connection device 180 is disposed within the interior of segment 12c. One end of the tension cable 18 is anchored to the floating connection device 180 while the opposite end of tension cable 18 is anchored within segment 14c. One end of the slack control member 182 is also anchored to the floating connection device 180 while the opposite end of slack control member 182 is anchored within segment 12c.
The slack control member 178 stretches and retracts to slacken and tension, respectively, the tension cable 18. This facilitates the folding and unfolding of the frame structure 10. As seen in
As seen in the figures, the tension cables and the elastic cords anchor at points within their respective frame members such that one or both extend through multiple segments of the frame members. However, this is not required. the tension cables and/or the elastic cord in any of these embodiments may be anchored at any frame member segment.
Those skilled in the art will recognize that the support frame 100 described herein represents only one exemplary embodiment, and that many variations thereof may be used. The frame structure 10 that is the basis for the support frame 100 can be used in an almost endless variety of structures. Such structures include, but are not limited to, tents and canopies, chairs and tables, strollers, luggage carriers, utility carts, beds and cots, displays, canes and walkers. Therefore, the present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
