Suction cup for use on windows

Abstract: An improved suction cup (110) made of a light transmissive material is provided having a head (112) and a cup portion (114) a concave interior surface adapted to contact a window and an exterior surface opposite said interior surface. A ridge (118) of material is provided along the outer portion of the exterior surface, so that, when the suction cup is in a sealing position, the ridge of material is generally parallel to the mounted surface. In such an arrangement, light (130) passing through the ridge (118) of material continues in a straight path (134) and does not converge at a focal point (140). Alternatively, surface deformations, such as grooves circular ridges, dimples, and roughing, may be provided on the exterior surface of the suction cup. These surface deformations diffuse the light passing therethrough, preventing all of the light from converging at a focal point.

Description: Technical Field This invention relates to the fields of suction cups and more particularly to the field of transparent and translucent suction cups adapted to be mounted on window surfaces such as those found in an automobile. Background of the Invention Typical suction cups, whether circular or oval in shape, utilize a concave interior surface which, when mounted upon a surface, evacuates the air from within the cavity and secures the suction cup to the mounted surface by means of vacuum. For ease of manufacture and use, the cross-section of the suction cups is generally tapered toward the edge. Usually, the exterior surface is straight, or, if convex, the convex exterior surface has a greater arc than the concave interior surface. When firmly secured to the mounted surface, the suction cup has a generally frusto-conical shape. The body of the suction cup formed of transparent or translucent plastic which has a concave interior surface may act as a lens which focuses the light passing therethrough at a single point. When attached to the back window of an automobile, the suction cup can under certain circumstances, act like a magnifying glass by converging the sun's rays at a single focal point. When this focal point falls on the fabric or back panel of an automobile, the converged sun's rays will heat up and possibly mar the surface of the fabric. If the right conditions occur, it is possible that the focused rays of the sun might damage the fabric or back panel of the automobile. Disclosure of Invention The invention is characterized by the features of claim 1. We have found that the problem of the converging rays passing through the suction cup is a function of the frusto-conical shape of the suction cup. We have also found that if an irregularity or discontinuity is provided to the exterior surface of the suction cup, the problems caused by the converging rays are dissipated. More particularly, we have found that if a ridge of plastic is provided along the outer rim of the suction cup, the light rays passing through the ridge will be redirected. If the exterior surface of the ridge is generally parallel to the surface upon which the suction cup is mounted, the light rays pass straight through the ridge and do not converge at a focal point. By providing such a ridge along the rim of a suction cup, the problem of the light rays converging at a focal point is significantly reduced. Brief Description of Drawings Figure 1 is a cross-sectional side view of a typical prior art suction cup. Figure 2 is a cross-sectional side view of the suction cup of Figure 1 when mounted on a surface. Figure 3 is a cross-sectional side view of a presently preferred embodiment of the suction cup of the present invention. Figure 4 is a cross-sectional side view of the suction cup of Figure 3 when mounted on a surface. Figure 5 is a cross-sectional side view of a first alternative embodiment of the suction cup of the present invention. Figure 6 is a cross-sectional side view of the suction cup of Figure 5 when mounted on a surface. Figure 7 is a cross-sectional side view of a second alternative embodiment of the suction cup of the present invention. Figure 8 is a cross-sectional side view of the suction cup of Figure 7 when mounted on a surface. Best Mode for Carrying Out the Invention Figures 1 and 2 show the typical suction cup of the prior art. Suction cup 10 has a head 12 and a cup portion 14 having an interior concave surface and an exterior surface. Commonly, such suction cups are molded from a transparent or translucent plastic such as vinyls. Hereinafter, it should be understood that the term suction cup refers to those suction cups which are made of a light transmissive material. Cup portion 14 is adapted to mount upon mounted surface 20 as shown in Figure 2. When mounted on a surface 20, the exterior surface of cup portion 14 has a generally frustro-conical shape illustrated as 16. Light 30 passing through frusto-conical portion 16 follows the path shown in 32 to converge at a focal point 40 some distance from the mounted surface. If focal point 40 coincides at or near a fabric or other flammable surface, the concentrated light rays 30 may singe, melt or damage the fabric or plastic flammable surface. On larger suction cups, we have found that a tapered cross section that exceeds 3 square inches (6.5 cm²) might, under certain circumstances, focus light rays with enough intensity to possibly mar some surfaces. Figure 3 shows the suction cup of Figure 1 with a present preferred improvement provided thereon. In Figure 3. suction cup 110 has a head 112 and a cup portion 114 having an interior concave surface and an exterior surface. A ridge of material 118 is provided along the rim 115 of the exterior surface of the cup portion 114 of the suction cup. Preferably, this ridge covers approximately one-half of the exterior surface of the suction cup. When suction cup 110 is depressed and mounted on surface 120 as shown in Figure 4, ridge 118 is aligned generally parallel to mounted surface 120. In the suction cup embodiment 110 of Figure 4, frusto-conical section 116 of cup portion 114 is reduced in size. Consequently, converging rays 137 are reduced by an amount which corresponds to the size of that ridge 118. We have found that when ridge 118 covers half the outer surface area of the cup body the amount of light 130 being focused is cut 50%. The other 50% of the light passing through suction cup 110 passes straight through as shown in directional lines 134. We have found that sufficient minimization of the converging light rays 137 can be achieved where ridge 118 extends at least one-third of the radial distance inward from the rim 115 of cup portion 114. A radius 119 is provided along the outer edge of ridge 118, the radius 119 being equivalent to the thickness of suction cup 110 at the interior portion of ridge 118. The exterior surface of ridge 118 extends from at least one third of the radial distance inward from the rim 115 until it intersects the radius 119 provided on the outer edge of cup portion 114. We have found that a one-quarter inch (0.64 cm) is a sufficient width for ridge 118 to safely reduce the converging light rays 130 passing through a medium-sized suction cup 110 having a diameter of 1 5/8 inches (4.1 cm). One could achieve the same results as suction cup 110 by having an equally-thick flange extend outward from the base of the head 112. However, that configuration would require substantially more plastic and would significantly increase the expense of molding. Because that amount of plastic would take a long time to cool, a suction cup having an equally-thick flange at the base of the head could not be ejected from its mold until after a significant delay. We prefer to make ridge 118 on the rim 115 of cup portion 114 to minimize the amount of plastic required while obtaining the required dispersion of light and get a thick cross-section where the flange meets the head of the cup. Use of ridge 118 is but one method available to disturb the convergence of light rays at a focal point when passing through a suction cup. Other methods such as surface irregularities or the provision of a square exterior surface parallel at all points to the mounted surface can also be used to minimize the problems caused by the converging light rays at a focal point. Figures 5 and 6 show an alternative embodiment of our suction cup. Suction cup 210 has a head 212 and a cup portion 214 having an interior concave surface and an exterior surface. Grooves 218 are provided on frustroconical section 216 of cup portion 214. As shown in Figure 6, grooves 218 scatter light rays 230 such that a reduced portion of light rays 232 converge at focal point 240. Scattered rays 234 do not converge at focal point 240, thereby obtaining sufficient dispersion of light. However, it is found that the presently preferred embodiment of Figures 3 and 4 provides the easiest such suction cup to mold. Figures 7 and 8 show another alternative embodiment of our suction cup. Suction cup 310 has a head 312 and a cup portion 314 having an interior concave surface and an exterior surface. Circular ridges 318 are provided on frustoconical section 316 of cup portion 314. As shown in Figure 8, ridges 318 scatter light rays 330 such that a reduced portion of light rays 332 converge at focal point 340. Scattered rays 334 do not converge at focal point 340, thereby obtaining sufficient dispersion of light. Suction cup 310 can be used when decorative appearance is not important. Vapor blasting or roughing of the exterior surface and molding ridges around the cup can be used to scatter the light. However, these alterations, like those in Figures 5-8, make the suction cup more visible and detract from its appearance. The suction cup 110 of Figures 3 and 4 does not provide a distracting or unsightly surface that can catch dust or be so obvious as to distract attention from the decoration hanging from the suction cup. Suction cup 110 is attractive, removes the possibility of excessive light hitting a focal point, and reduces both material and manufacturing time.

Claims: A suction cup (110,210,310) made of light transmissive material, the suction cup having a head (112,212,312) and a cup portion (114,214,314), the cup portion having a convex exterior surface (116,216,316) and a concave interior surface for contacting a mounting surface (120,220,320), CHARACTERIZED IN THAT the exterior surface (116,216,316) has at least one surface irregularity or discontinuity such that the light rays (130,230,330) passing through the suction cup do not converge at a single focal point (140,240,340). A suction cup (110) according to claim 1, wherein the surface irregularity or discontinuity comprises a ridge (118) of light transmissive material sized and shaped to be generally parallel to the mounting surface (120) when the suction cup is mounted thereon. A suction cup (110) according to claim 2, wherein the ridge (118) covers approximately one half of the exterior surface (116) of the cup portion (114). A suction cup (110) according to claim 2, wherein the ridge (118) extends inwards from the edge of the cup to intersect the exterior surface (116) of the cup portion at a distance of at least one third of the radial distance inwards from the edge, and wherein an outer portion (119) of the ridge (118) is rounded with a radius approximately equal to the thickness of the suction cup where the ridge intersects the exterior surface. A suction cup (210) according to claim 1, wherein the surface irregularity or discontinuity comprises a plurality of grooves (218) provided in the exterior surface (216) of the cup portion (214). A suction cup (310) according to claim 1 wherein the surface irregularity or discontinuity comprises a plurality of circular ridges (318) provided in the exterior surface (316) of the cup portion (314). A suction cup according to claim 1, wherein the surface irregularity or discontinuity comprises a roughening of the exterior surface of the cup portion. A suction cup according to claim 7, wherein the roughening of the exterior surface of the cup portion is produced by vapour blasting.

Inventors: ADAMS WILLIAM E, PEOPLES MARK, ADAMS, WILLIAM E., PEOPLES, MARK
Applicants: ADAMS MFG CORP, ADAMS MFG. CORP.
Application year: 1991
Main classification: F16B47
IPC codes: F16B47, A45D42, B60J1