US 2620869 A
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Description (OCR text may contain errors)
Dec. 9, 1952 J. L. FRIEDMAN VENETIAN BLIND SLAT CONSTRUCTION Filed May 3, 1950 III. w
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Patented Dec. 9, 1952 i'iED STATES .tzsta PATE'E Claims.
This invention relates generally to the Venetian blind art and more particularly to a novel and useful Venetian blind slat construction.
Heretofore Venetian blind slats have been composed of wood or metal and such slats have had a number of inherently poor qualities.
In the case of wood slats unless very carefully treated, the wood is subject to warping. Further, even when no color is desired it is necessary to coat the wood to prevent the deleterious effects of moisture absorption. Where holes are punched in the wood to permit the passage of elevating cords the rough edges have an abrading efiect upon the cord. Wooden slats have a low degree of flexibility and if accidentally distorted beyond their elastic limit they become broken. Another disadvantage of wooden slats is that they have to be relatively thick for structural stability and thus cut down the amount of light entering a room when the Venetian blind is in the open position thereof.
Metal slats while thinner, require coating, and where the metal is steel or aluminum they are subject to rusting and corrosion and require maintenance. While metal slats are capable of withstanding greater distortion than wood they may become permanently distorted. It is therefore among the principal objects of the present invention to provide slat construction wherein the foregoing disadvantages of prior art constructions are reduced to a minimum and in some cases avoided entirely.
Another object of the present invention lies in the provision of Venetian blind slat construction in which the color of the slat is incorporated directly therein. This obviates the need for painting in the first place and reduces the maintenance expense since the slats need only a minimum of cleaning to restore them to their original condition.
Another object herein lies in the provision of novel Venetian blind slat construction having a high degree of elasticity so that very severe distortions of the blind may be indulged in and upon release of external pressure or tension the slats return to their initial or original shape and position.
A feature of the invention lies in the fact that the slats are of light weight. This makes the blind easier to manipulate for tilting and raising and lowering and also enables the supporting structure of the blind to be more lightly constructed with a consequent reduction in cost.
By virtue of the fact that pigmentation is incorporated directly into the slat, not only is there no paint to chip or corrosion to occur, but the translucency of the slat may be controlled so that even in a closed position light may be admitted but of a pre-determined desired reduced intensity.
Another object herein lies in the provision of Venetian blind slat construction in which the slat is subjected to a pre-tensioning which produces a tempered effect so that the slat offers greater resistance to distortion under stress.
A still further object lies in the provision of slats of the class described which are composed of organic polymers.
Another object herein lies in the provision of cambered slats which are concave in cross-section in an upward direction to avoid distortion or sagging at elevated temperatures.
These objects and other incidental ends and advantages will more fully appear in the progress of this disclosure and be pointed out in the appended claims.
In the drawings, similar reference characters designate corresponding parts throughout the several views.
Figure l is a fragmentary perspective view of a Venetian blind showing an embodiment of the invention.
Figure 2 is a fragmentary view in perspective of one of the Venetian blind slats in accordance with the invention.
Figure 3 is a schematic perspective view showing stages in the process for producing the Venetian blind slats.
Figure 4 is a fragmentary view in perspective of another form of slat having a double camber.
In accordance with the invention a Venetian blind generally indicated by reference character it comprises a head ll, tilting and supporting tapes l2 and i3, elevating cords l4 and I5, tilt cords l6 and H, a bottom rail l8 and a plurality of slats 2d. The head H may be in the form of an open or closed head rail and the other parts of the Venetian blind I!) with the exception of the slats 28 may be of Well known construction so that a detailed description thereof is deemed unnecessary for the present disclosure. As seen in Figure 2 the slat 20 has a top surface 22, a bottom surface 24, lateral edges 26 and 28 and end edges 30 and 32. The slat 20 may be provided with orifices 34 and 36 through which the cords Hi and I5 may pass in a Well known manner. The slat 20 is composed of a substantially homogeneous material which is a single organic polymer or a mixture of organic polymers which are generally referred to as plastic material. Among such polymers are vinyl compounds or derivatives, such as polystyrene, vinyl chloride and co-polymer of or including such compounds or derivatives, which possess the well known physical property known as elastic memory.
I have found that while such materials present good stability when they are relatively thick, they are subject to the disadvantage then of high cost and high light blockage. When slats are made of such materials of little thickness, that is to say when the distance between the top surface 22 and the bottom surface 24 is of the order of .010 inch to .020 inch I have found that they will not maintain a desired shape and linearity unless the slats are pre-tensioned or given a temper by drawing the same when they are in a softened condition.
Such drawing or stretching of the material of which the slat is composed may be accomplished in a number of different ways and one such method is shown in Figure 3 where a band of organic polymers is shown being treated.
In-Figure 3, the web or band of organic polymers generally indicated by reference character 48 is supplied in a substantially continuousstrip from a source not shown and is fed in the direction of the arrow 42 by the feeding rolls 4'4 and 43. The feeding rolls t4 and G6 operate to feed the band so between them at a first pre-determined rate of speed. These rolls may be power driven by suitable means not shown.
After leaving the rolls 44 and 45, the band 4% is subjected to heat and this may be provided by infra-red radiation lamps M359, or by a high frequency power generator (not shown), or in any other suitable manner.
The forming and stretching rolls 52 and E i serve to make the band 43' concave when viewed from above and since the rolls 52 and 54 are operated at a greater peripheral speed the band is stretched while in a softened state. This results in molecular orientation. After being thus altered the band 43 may be air cooled or liquid cooled by the bath 56, passing about the guide rolls 58 and 50. The band 46 as thus altered to form Venetian blind slat stock is indicated by reference character 62.
The relative strength of the slats in resistance to distortion is increased by stretching the same in two directions, each generally in the plane of the slat so that either before or after the stretching shown in Figure 3 the slat may be softened and stretched in a direction transverse with respect to the arrow 42. This may be performed either in the individual slat or in larger parts from which the slats are blanked.
The camber or radius given to the slat about the longitudinal axis thereof as viewed in Figure 2 may be produced either simultaneously with the previously described stretching operations or'may be done as a last step. This radius or camber makes the slat multiplanar or irregular in crosssection and enables the slats to support themselves against relatively long reaches between the tapesl2 and I3. By virtue of the shape and arrangement of the slat cambers, I have found that they are capable of supporting themselves in a substantially straight line under a temperature differential of at least 25 Fahrenheit, greator than normal.
In connection with the orientation of the slat material, this may be done in such manner that the cooling so as to fix the orientation is accomplished while the material is still under tension. This may be done for example by tensioning means (not shown) located above reference character G2 in Figure 3.
Thus by a combination of the orientation of the resilient plastic material as well as by the shape and arrangement thereof 'slats have been produced in accordance with the invention which have differential resiliency about intersecting axes and may withstand large mechanical distortion and an increased ambient temperature of 25 to 35 without substantially losing their shape.
I Wish it to be understood that I do not desire to belimited to the exact details of construction shown and described, for obvious modifications will occur to the person skilled in the art to which the invention pertains.
1. A slat for Ventian blinds of molecularly oriented plastic material, said plastic material having the characteristics of elastic memory, and having a transverse curvature and characterized by a differential resiliency about the intersecting axes to maintain initial shape.
2. A slat for Venetian blinds of a molecularly oriented plastic material containing organic polymer, said plastic material having the characteristics of elastic memory, and having a transverse multi-planar surface and characterized by a differential resiliency about the intersecting axes to maintain initial. shape.
3. A slat for Venetian blinds of molecularly oriented polystyrene, said polystyrene having the characteristics of elastic memory, and having a transverse irregular surface and characterized a differential resiliency about the intersecting axes to maintain initial shape.
4. A slat for Venetian blinds of an organic polymer molecularly oriented along one of the axes and having the characteristics of elastic memory, said slat having a transverse multiplanar surface and characterized by a differential resiliency about the intersecting axes to maintain initial shape.
5. A slat for Venetian blinds of molecular-1y oriented plastic material having the characteristics of elastic memory and having a transverse multi-planar surface in section which is symmetrical about the central longitudinal axis of said slat and characterized by a differential resiliency about the intersecting axes to maintain initial shape.
J. LEON FRIEDMAN.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,121,217 Ellis June 21, 1938 2,229,225 Schneider Jan. 21, 1941 2,315,640 Morse Apr. 6, 1943 2,535,926 Hunter et al Dec. 26, 1950