Wear Insert for a Door Channel

This invention relates to an insert for a door channel and more particularly to a wear insert removably mounted in the track of a beverage truck to increase wear resistance of the track.

Beverage trucks, such as shown in FIG. 1, typically include on each side a pair of doors 10 having articulated longitudinal panels and supported on rollers that roll in channels 14 extending vertically upward from the base of the truck to expose the inside of the truck. Driving motion of the truck places aerodynamic and inertia loads on the doors causing the rollers to rattle both transversely to and along the axis of the vehicle. The transverse motion places vibration loads on the channel, the truck and securements such as welds. Axial vibrating movement of the rollers along the axis of truck movement, which is also the axis for the roller axle, causes the rollers to unnecessarily rub against the channel. This oscillating rubbing causes a small portion of the channel to wear out prematurely. The channel, which is typically made of aluminum to reduce weight, is relatively soft and thus prone to wear, and is expensive to replace.

A prior art approach that addresses this problem is illustrated in FIG. 2. In FIG. 2 a stainless steel strip 16 is inserted endwise into a recess formed between lateral ribs of the channel extruded of aluminum. The stainless steel strip is held in place by striking surface of the strip with a punch with a sufficient force to permanently distort the strip and the aluminum surface at 17. This distortion makes the strip unable to slide. While the metal strip does not wear, the aluminum surface is very thin and after a time the metal strip 16 and the aluminum backing surface are indented by the force of the roller 12 hitting against the two. The results are the same as the wear, a pitted F region. In addition, problems of electrolytic corrosion are introduced by the dissimilar metals. Further, replacement of a worn insert is not possible because of the deformation process.

The general object of this invention is reduction of unnecessary wear on expensive metal channels by provision of an inexpensive insert which is easy to install, and repositionable in the field. In addition, use of a nonmetal insert comprised of nylon instead of stainless steel eliminates galvanic corrosion between dissimilar metals.

The foregoing objects and advantages will become more apparent when viewed in light of the accompanying drawings and following detailed description wherein:

FIG. 1 shows a prior art beverage truck having a pair of side doors mounted on rollers for overhead movement in vertical channels.

FIG. 2 is section view taken along lines II--II of FIG. 1 of the side doors rollably disposed in the channel.

FIG. 3 is a section view of a channel having a wear insert in accord with the invention.

FIG. 4 is a section view of the wear insert spaced from the channel.

FIGS. 5, 6 and 7 are section views showing the wear insert being installed in the channel.

Turning now to the drawings, FIG. 3 shows a wear resistant track assembly 18 for a pair of side-by-side articulated doors--20A, 20B (shown in phantom) each supported on axles 28A, 28B rollably connected to rollers 26A, 26B and movable in and along the track. As shown, the track is generally I-shaped in section and includes an upper flange 30, a lower flange 32 having a lateral edge surface 33, and a partition 34 extending perpendicularly between the flanges. The doors 20A, 20B each have a moisture guard 24A, 24B captivated in the upper flange to engage the outer surface 22A, 22B of their associated door. The mounting of door 20A at its other end would appear like that shown for door 20B and door 20B at its other end would appear like that shown for door 20A.

In accord with the present invention, the lower flange on each side of the partition has been extruded to include a pair of shaped ribs 36 and grooves 38 extending upwardly from a recessed base 37 and longitudinally along the track and specially configured to receive a wear insert 50. As shown the wear insert cooperates with the track to define smooth flush surface 54 for the rollers to bear against and is recessed. The track 18 is preferably extruded from an aluminum such as 6061-T6. Stops at the top and bottom of the track are preferably provided to inhibit vertical movement of the insert.

FIG. 4 shows the wear insert 40 positioned above the track for downward mounting insertion therein. Since the track is symmetrical only one side will be described. The track includes a plurality of parallel elongated and laterally spaced ribs 40 which define a corresponding plurality of elongated grooves or shallow recesses 44 between the ribs, two of the ribs including a diamond shaped head 42. A medial rib 46 is provided as an anvil or support for limiting movement of the insert. A pair of recessed ledges 48 are adjacent to sidewalls 49 and provided to support the lateral edges of the insert as well as to limit the inward insertion.

The wear insert 50 has top and bottom surfaces 52, 54, a pair of laterally spaced longitudinally extending edges 56, 58 each adapted to seat on one of the ledges, a pair of locking members 60 each including a pair of arcuate flexible flanges 62, 64 each extending upwardly from the bottom surface to terminate in free ends 63, 65 and a medial rib 66 adapted to engage the anvil 46. Each locking member 60 is adapted to interlockingly engage with one of the shaped heads.

Preferably the insert is comprised of a tough yet relatively inexpensive polymer such as nylon. Use of such a nonmetallic material obviates potential electrolytic action between the insert and track, is "harder" than aluminum, is flexible enough to allow snap-in installation, and is relatively inexpensive without a sacrifice in function. In the preferred embodiment, the insert 50 is amde from DuPont Zytel ST-901, a super tough resin having amorphour characteristics, is non-brittle and has good extrusion properties.

The heads 42 are generally diamond-shaped and defined by a forward first pair of angled surfaces 42a and a rearward second pair of angled surfaces 42b. The first and second pairs of angled surfaces 42a and 42b defined opposite corners of the diamond shape with the apex of each corner being connected by an imaginary line "I" (see FIG. 5) therethrough and through the body 44. The first pair of surfaces 42a defines a cam A (see FIG. 5) which spreads the arcuate flanges 62, 64 laterally to allow downward snap-fitting of the flanges about the head and the second pair of surfaces 42b define a cam "B" (see FIG. 5) which spreads the arcuate flanges to allow removal. Relative to the imaginary line "I", the first cam is defined by an included angle of about 65.degree.-75.degree. and the second cam is defined by an included angle of about 100.degree.-120.degree..

FIGS. 5, 6 and 7 show interlocking of the insert 50 by a downward insertion of the insert into the track whereby each respective pair of flanges 62, 64 engagingly interlocks with one of the shaped heads 42. The stop surfaces in the track provided by the anvil 46 and rib 66 in the insert 50 limits how far down the insert will go when snapped downwardly into the channel. Because of the recessed fit, after installation the wear strip has its planar top surface 52 flush with the edge of the aluminum post allowing smooth operation of the doors.

Additionally, it will be appreciated that the design of the present invention facilitates convenient repair and/or replacement of the insert 50 in the field. In particular, it will be noted that the present wear insert is configured so that the right and left halves of the insert, relative to its longitudinal axis, are equivalent to each other. Accordingly, once worn, the insert is adapted to be easily pried upwardly from the track and its opposite ends juxtaposed so as to present a fresh wear surface to the rollers. As indicated in FIG. 3, letters A and B and A' and B' represent like lateral edge portions of a first and a second insert. If the first insert to the right of partition 34 has worn adjacent edge B where the wheel has rested, the first insert can have its opposite longitudinal ends juxtaposed so that the lateral edge A is now adjacent the partition and the worn edge B is spaced from the partition. In like manner the first insert can be translated to the left of partition 34 such that its fresh lateral edge A is adjacent the partition and the second insert translated to right of the partition such that its fresh lateral edge A' is adjacent the partition. An important benefit of this feature of the present invention is that it essentially doubles the useful life of the wear insert.

Further, while shown being installed downwardly, the symmetrical nature of the insert 50 and track 18 is such that endwise insertion of the insert is possible if required by a particular application.

While the above description constitutes the preferred embodiment, it will be appreciated that the present invention is susceptible to modification and change without departing from the fair meaning or proper scope of the accompanying claims.