US2577227A

US2577227A - Ladder tape

Info

Publication number: US2577227A
Application number: US90625A
Authority: US
Inventors: George F Brent
Original assignee: Hunter Douglas Inc
Current assignee: Hunter Douglas Inc
Priority date: 1949-04-30
Filing date: 1949-04-30
Publication date: 1951-12-04
Anticipated expiration: 1968-12-04

Description

G. F. BRENT LADDER TAPE Dec. 4, 1951 Filed April 50, 1949 2 Q m Q 1 K l h 2 0 A 6 2 A b v 7 M 4% 2 Fi 6. Fly. 2

v Zhwemor Georye F571 Cittornegs Patented Dec. 4, 1951 LADDER TAPE George F. Brent, Pittsburgh, Pa., assignor to Hunter-Douglas Corporation, Riverside, Calif... a corporation of Delaware Application April 30, 1949, Serial No. 90,625

Claims.

. My invention relates to Venetian blinds, and particularly to the flexible hangers or ladder tapes for supporting the slats of the blinds in suspended position within the area of the Window or other opening to be screened.

The usual Venetian blind hanger or ladder tape comprises a pair of elongate, relatively narrow, flexible straps which are spaced apart in parallelism and transversely interconnected by a series of flexible cross bands. The cross bands are spaced apart at uniform intervals longitudinally of the pair of straps.

In service two or more ladder tapes are secured in horizontally spaced relation to a horizontal supporting bar pivoted at the top of the window or other opening to be screened. The ladder tapes extend in parallel relation vertically downward from the horizontal bar, with the cross bands of the ladder tapes aligned horizonta ly, to provide support for the slats of the blind structure.

The usual ladder tape is constructed of woven fabric, and the union of the cross bands to the vertical straps is effected by interweaving the ends of the cross bands with the bodies of the straps. The ladder tapes as thus constructed are of neat and pleasing appearance, and, when new, they afford the intended utility. However, such ladder tapes are relatively expensive, and,

being formed of fabric, they tend to shrink and to become distorted when they are washed, as they must be from time to time in service. Furthermore, the fabric ladder tapes are, forartistic reasons, colored or dyed in desired hues, but under the effect of sun rays and light the colors tend to fade, thus detracting from the desired appearance of the Venetian blind structure.

The object of my present invention is to provide an improved ladder tape structure for Venetian blinds which may be constructed of an inexpensive material and in an inexpensive manufacturing procedure. It is further my object to provide a ladder tape which will endure cleaning without shrinking, fading, or becoming distorted. Other objects will be apparent in the ensuing specification.

In accordance with my invention, I form a novel ladder tape structure of a plastic material which is highly flexible, capable of being colored in lustrous and enduring hues, resistant to objectionable distortion under the weight of the supported slats, and adapted for manufacture in a welding or fusing operation, as will presently appear.

The invention will be understood upon reference to the accompanying drawings, in which:

Fig. 1 is a fragmentary view in front elevation of a Venetian blind in which a ladder tape of my invention is embodied;

Fig. 2 is a fragmentary View, presenting the ladder tape as it appears from the right of Fig. 1, the view in Fig. 2 being presented on larger scale than Fig. 1, with the ladder tape shown partly in elevation and partly in medial, vertical section;

Fig. 3 is a view in horizontal section of the ladder tape, as shown on the plane III-III of Fig. 2;

Fig. 4 is a view comparable with Fig. 3, illustrating a modification in structural detail;

Fig. 5 is a view generally similar to Fig. 2, illustrating further modifications in the construction of the ladder tape of this invention; and

Figs. 6 and '7 are views similar to Figs. 2 and 5, severally illustrating still other modifications in details of construction.

Referring to the drawings, Fig. 1, illustrates only so much of a simplified form of a Venetian blind structure as is necessary for a description of the invention. The illustrated blind comprises a supporting bar 2 which carries pins 3 at its two ends, by means of which the bar jslats 8 in vertically spaced relation, the slats being indicated in full lines in Fig. 1, and in broken lines in Fig. 2. It will be understood that the ladder tapes 4 are secured at their lower ends to a basal bar (not shown), and that the blind structure may include means for tilting the supporting bar 2 on the horizontal axis of its aligned pivots 3, whereby the front and back straps 5 and 6 may be vertically shifted relatively to each otherthe front straps 5 upwardly, and the back straps 6 downwardly, or vice-versa, with the efiect that the cross bands 7 and the slats borne thereby are tilted in well-known manner.

The conventional Venetian blind includes at least two vertical adjusting cords 9. These cords are anchored at their lower ends to the lowermost slat or basal bar of the blind structure, and extend upwardly through openings, provided therefor in the slats e and cross bands I, to the supporting bar 2, whence the cords are trained over pulleys (not shown) and extended to one side of the blind structure, to provide pull-cords for drawing the slats vertically together and regulating the effective vertical extent of the blind structure. As the slats are thus drawn vertically together the intervening portions of the straps 5 and 6 of the ladder tape buckle or gather in known way. For further detail of a Venetian blind structure of the sort here alluded to, and in order to exemplify the various types of blinds in which the ladder tape of my invention may be used, reference is made to Letters Patent No. 2,012,034, granted to me on August 20, 1935.

The cross bands I of the ladder tape comprise loops formed in and offset laterally from the bodies of the straps. The simplest form of the structure is shown in Fig. 5, in which the cross bands I consist of loops formed in the strap 5. The two limbs of each loop are united on a line H! at the plane of thestrap 6, and the closed end or bight of the loop is united, as at H, to the inner face of the strap 5. The limbs of the loops, thus forming the cross bands l of the ladder tape for the support of the slats 8, may be cemented or fused (as will presently appear) in face-to-face contact, as shown in Fig. 5, or

the loops may be united only on the lines Ilia and Ila, as shown in Fig. 6, and the slats 8a slid into position and supported between the limbs of the loop. Elliptical orifices l2 are formed in cross bands for registry with the usual openings formed in the slats for the passage of the adjusting cords 9, Figs. 1 and 2.

In Fig. '7 it will be seen that the cross bands 1 "lb may be formed by a series of spaced loops formed in both of the vertical straps 5b and 6b of the ladder tape structure. Each loop is closed and united on a line lfib at the plane of the strap in which the loop is formed, so that the continuity of the strap is in effect uninterrupted, as in the case' of the other structures described. However, in the structure of Fig. '7, the loops need not extend across the entire interval between the two vertical straps, but only half way,

where the loops are united pair by pair, on lines indicated at Hb, to form the cross arms lb of the ladder tape.

Returning to Figs. 1 to 3, the cross arms 1 will be seen to be also formed by loops offset from the bodies of both straps 5 and 6, but in this case the loops are such in length that they may be overlapped and united, as shown in Fig. 2,

thereby affording, in those cases where desired, greater strength and security of the loops than is had in the structure of Fig. 7. Fig. 3 illustratesin plan the orifices [2 formed in the cross arms I for the passage of an adjusting cord 9,

and Fig. 4 illustrates a valuable feature of structural detail; that is, a slot l3 may be formed in each cross band of the ladder tape, the slot extending outwardly from each orifice l2 and opening through one of the lateral edges of the cross band, whereby the ladder tape may be disengaged from the cords 9 without removing the cords from engagement with top and bottom bars of the blind structure. This facilitates the removal 'of the tapes for cleaning or renewal.

It has hitherto been proposed that ladder tapes be constructed of strips or hands of a highly flexible thermoplastic material, such as a polyvinyl chloride, ethyl cellulose, cellulose acetate, cellulose acetate butyrate, methyl methacrylate, polyethylene, or other suitable thermoplastic substance. Indeed, strips or bands of cloth impregnated and/or coated with such plastic material have been proposed. In accordance with my invention I not only may form my improved ladder tape of such a material, but I have discovered that the described union of the loops may be efiected by welding; that is, by the application of pressure and heat in the areas or on the lines where union is desired, the plastic substance of the tape is so far softened that a fusion and weld is effected. More specifically, by applying heat and pressure along the lines 10 where the loops are secured at the plane of the straps 6 (and/or 5) the desired permanent union is obtained. Also, the union (H and Ila) of the closed ends or bights of the loops with the strap 5 may be effected, and so too the union of the paired loops in the structure of Fig. 7 is effected on the lines llb. Additionally, the two limbs of each loop may be permanently welded face to face over their entire common area, or they may be united on one or more lines of weld, the dotted lines M in Fig. 3 illustrating a single line of weld. In the structure of Figs. 1 to 3, the overlapped loops may be welded over their entire common area, or over such lines of weld as may be desired.

The foregoing specification will provide to those skilled in the art a full understanding of my invention, and the modifications and variations permissible without departing from the spirit of the invention defined in the appended claims will be apparent.

I claim:

'1. In a ladder tape for Venetian blinds comprising two fiexible straps extending in parallel spaced relation and provided with cross bands at longitudinally spacedv intervals for the support of slats; the invention herein described wherein said cross bands comprise loops formed in and offset from the body of one of said straps, with the two limbs of each loop welded face to face and securely united at the plane of the strap in which it is formed, to maintain strap continuity, and extended laterally therefrom and united to the other strap.

2. In a ladder tape for Venetian blinds comprising two flexible straps extending in parallel spaced relation and provided with cross bands at longitudinally spaced intervals for the support of slats; the invention herein described wherein said cross bands comprise loops formed in and offset laterally from the bodies of said straps, with the two limbs of each loop united at the plane of the strap in which it is formed, to maintain strap continuity, the loops formed in the two straps being united pair by pair to form said cross bands.

7 3. In a ladder tape for Venetian blinds com,- prising two flexible straps extending in parallel spaced relation and provided with cross bands at longitudinally spaced intervals for the support of slats; the invention herein described wherein said, cross bands comprise loops formed in and offset laterally from the bodies of said straps, with the two limbs of each loop united at the plane of the strap in which it is formed, to maintain strap continuity, the loops formed in the two straps being overlapped and united pair by pair to form said cross bands.

4. In a ladder tape for Venetian blinds comprising two flexible straps extending in parallel spaced relation and provided with cross bands at longitudinally spaced intervals for the support of slats; the invention herein described wherein said cross bands comprise loops formed in and ofiset laterally from the bodies of said straps, with the two limbs of each loop united at the plane of the strap in which it is formed, to maintain strap continuity, the loops formed in the two straps being united pair by pair to form said cross bands, and medial openings formed in the paired and united loops to provide cord passages.

5. In a ladder tape for Venetian blinds comprising two flexible straps extending in parallel spaced relation and provided with cross bands at longitudinally spaced intervals for the support of slats; the invention herein described wherein said cross bands comprise loops formed in and offset laterally from the bodies of said straps, with the two limbs of each loop united at the plane of the strap in which it is formed, to maintain strap continuity, the loops formed in the two straps being overlapped and united pair by pair to form said cross bands, and medial openings formed in the overlapped and united loops to provide cord passages.

6. The structure of claim 1, with medial openings formed in the bodies of such loops to provide cord passages, and slots extending from said openings through one edge of each cross band formed by said loops.

7. The structure of claim 5, with slots extending from said openings through one edge of each cross band formed by said loops. 7

8. A ladder tape for Venetian blinds including two flexible straps comprised of thermoplastic material and extending in parallel spaced relation, and a series of loops formed at regular longitudinally spaced intervals in the body of one of said straps only, with the two limbs of each loop closed face to face and united in a weld at the plane of the strap in which it is formed, said loops extending from the latter strap and being welded at the bights in the loops to the other strap to form slat-supporting cross bands.

9. A ladder tape for Venetian blinds including two flexible straps comprised of thermoplastic material and extending in parallel spaced relation, and a series of loops formed at regular longitudinally spaced intervals in the bodies of said straps, with the two limbs of each loop closed and united in a weld at the plane of the strap in which it is formed, said loops extending from said straps and being united in welds pair by pair to form slat-supporting cross bands.

10. A ladder tape for Venetian blinds including two flexible straps comprised of thermoplastic material and extending in parallel spaced relation, and a series of loops formed at regular longitudinally spaced intervals in the bodies of said straps, with the two limbs of each loop closed and united in a weld at the plane of the strap in which it is formed, said loops extending from said straps and being overlapped and united in welds pair by pair to form slat-supporting cross bands.

GEORGE F. BRENT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,937,342 Higbie Nov. 28, 1933 2,229,225 Schneider Jan. 21, 1941 2,405,579 Hunter Aug. 13, 1946 2,537,865 Stuber et al Jan. 9, 1951