US2742962A - Venetian blinds - Google Patents

Description

April 24, 1956 GRIESSER VENETIAN BLINDS 3 Sheets+Sheet 1 Filed March 29, 1954 INVENTOR:

F GRIESSER A ril 24, 1956 F. GRIESSER 2,742,962

' VENETIAN BLINDS Filed March 29, 1954 3 Sheets-Sheet 2 INVENTOR: F. GRIESSER April 24, 1956 F. GRIESSER 2,742,962

VENETIAN BLINDS Filed March 29, 1954 3 Sheets-Sheet 3 INVENTOR: 70 9 70 F. GRIESS'ER B Y 8 77 8 y l va ug United States Patent 2,742,962 VENETIAN BLINDS Fritz Griesser, Aadorf, Switzerland, assignor to Rolla d en- The present invention relates to Venetian blinds of the type in which the laths are carried by ladder members suspended from tilting frames pivoted on the winding shaft and movable to tilt the laths from horizontal or open to inclined or closed position, and in which pull members, each suspended from a winding drum of the winding shaft, are attached to the lowermost lath and may be wound or unwound from their drum in order to raise or lower the blind.

Venetian blinds of this type are known, in which clutch means are provided for changing the position of the laths, which clutch means are only operative for one direction of rotation of the winding shaft. Usually in this type of blinds the return of the tilting frame into its starting position is obtained by a spring. I

In contradistinction thereto the object of the present invention is to provide a Venetian blind, in which the tilting frame is forced into its corresponding end position upon actuation of the winding shaft in either direction of rotation.

For this purpose the Venetian'blind according to the present invention is provided with a ratchet and pawl device comprising a ratchet wheel rigidly mounted on the winding shaft and a follower ring in driving connection with the tilting frame and radially movable to a limited extent, said ring being provided on its inner surface with two substantially diametrically opposed noses, one of said noses co-operating over a part of a revolution of the winding shaft with the ratchet wheel when the winding shaft is operated to lower the blind and the other when the winding shaft is operated to raise the blind in order to pivot the tilting frame and adjust the laths.

Other objects and advantages of the invention will become apparent from the description now'to follow of preferred embodiments thereof and in which reference will be made to the accompanying drawings, in which:

Fig. 1 is a side view, partly in longitudinal section of one end portion of the casing containing the driving elements of a blind according to a first embodiment of the invention;

Fig. 2 is a section taken along the line II-II of Fig. 1;

Figs. 3 and 4 are sections similar to the one of Fig. '2, but illustrating other working positions of the different parts;

Fig, 5 is a section taken along the line VV of Fig. 1;

Figs. 6 and 7 are sections similar to the one of Fig. 5,

but showing the parts in the working position corresponding to the one of Figs. 3 and 4;

Fig. 8 is a side view, partly in longitudinal section, of one end portion of the casing containing the driving elements of a blind according to a second embodiment of the invention;

Fig. 9 is a section taken along the line IX-IX of Fig. 8; Figs. 10 and 11 are sections similar to the one of Fig.9

but showing the parts in other working positions; and

' Fig. 12 illustrates, partly in cross-section, a detail of a variant of the embodiment according to Fig. 8.

'vided in the laths.

. 55 (Figs. 5-7).

ice

In the drawings reference numeral 1 designates a casing of U-shaped cross-section and through which the winding shaft 2 passes. One endof the said shaft 2 carries at the outside of the said casing a winding drum 3 to which is fixed one end of a draw tape 4. In the first embodiment represented in Figs. 1-7 a tilting frame 52, 53 (Figs. 1-4) is pivotally mounted on each of the two end portions of the winding shaft 2 by means of two sleeve portions 50 having each a square block 51 at the end facing the other sleeve portion. The lateral parts 52 of each tilting frame are rigidly mounted on the associated square block 51, while one end of the two ladder tapes 8 for the laths 9 is laid onto the bent sheet metal piece 53 of the tilting frame and secured to this piece 53 in a way not represented. The tilting frame 52, 53 is arranged on the sleeve portions 50 in such a way that the axis of the partly cylindrical sheet metal piece 53 is excentrical with respect to the axis of the winding shaft 2, namely, when compared with the middle position of the tilting frame asshown in Fig. 3 (whereby the outer side of the blind is on the right hand side'in the drawing), displaced to a small amount outwardly and to a larger extent downwardly. Thus the tilting frame 52, 53 is unstable in its middle position (Fig. 3) and at a small deviation from this middle position it already tends to pivot to one of the two end positions shown in Figs. 2 and 4 under the influence of its own weight. In these end positions, which on the one hand are given by the corresponding closing position of thelaths, but which, on the other hand, could be limited by not represented abutments co-operating with the tilting frame, I the latter is stable. The ladder tapes 8 pass I through transversal apertures 10 provided in the'bottom of the casing 1. The laths 9 are held in bridges 11 fixed to the ladder tapes 8. A tape 12, preferably of steel or of a synthetic material passes through slots (Fig. 1) pro- The bent sheet metal part 53 of each tilting frame partly surrounds a drum 13 rigidly mounted on the winding shaft 2. This drum 13 is provided with a peripheral groove 13a (Fig. 1) on the bottom of which the end of the tapev 12 is fastened so that the said tape may be wound around the drum 13 by rotation of the shaft 2. The tape 12 passes through the bottom of the casing 1 and as already mentioned through a slot in each lath in order to be attached to the lowermost lath in not represented but known manner. The winding shaft 2 is supported by means of the cylindrical sleeve portions 50 on supports 17 secured to the casing 1. Y

I A' disc 54 is clamped to the sleeve portion 50-and provided on diametrically opposite points with radial slots Each slot 55 of the disc 54 is traversed by the shank of a screw bolt 56, which screw bolts 56 are screwed into a follower ring 57 in such a way that this ring 57 is radially displ-aceable with respect to the disc 54 to an extent corresponding to the length of the slots. In the zone of the two diametrically opposite screw bolts 56 the ring 57 is provided with rounded radial projections 58 adapted to co-operate with cham-.

fered surfaces 59a of an abutting ledge 59 crossing theupper, open end of the casing 1' and secured to the latter. The follower ring 57 is provided on its inner surface with two diametrically opposite driving noses 60. Moreover a ratchet wheel 61 is mounted on the winding shaft 2, which ratchet wheel is provided with four equidistantly arranged axial projections 62 projecting into themiddle opening of the follower ring 57 and destined to co-operate with the noses 60 of the latter.

The operation of the described Venetian blind is as follows:

Assuming that the blind is partly raised and that its difierentelements are in the position shown in Figs. 1,

wise .direction.

3 2 and 5. The laths 9 are in their one closed position (with their back turned outwardly) and the tilting frames 52, 53 are pivoted into one of their end positions (Fig. 2). If now the blind is lowered by rotating the winding shaft 2 in-a clockwise direction (Figs. 2 and 5) the wheel'61 of the ratchet and pawl device is also rotated in a clock- Thereby the projections 62 slide over the' noses 60 of the ring 57 without producingany-rotation of the latter. If it is desired to adjust the laths 9 in their horizontal middle position the winding shaft 2 is rotated in a counterclockwise direction. Thereby a notch 62 of the ratchet wheel 61 abuts against the shoulder of the upper nose 60 of the'ring 57 (Fig. 5),' resulting in the ring 57, the disc 54, the sleeve portion 50 andthe'tiltiug frame 52, 53 being also rotated 'in'a counterclockwise direction. Fig; 6 illustrates the position of 'the different elements of the ratchet and pawl device 54-42 when the laths 9' are in their horizontal middle positionshown in Fig. 3. If it is desired to adjust the laths 9 to their second end positions shown in Fig. 4, the winding shaft 2 is further rotated in a counterclockwise direction. The mentioned notch 62of theentrained ratchet wheel 61 co-operates with the nose 60 to further rotate the ring 57 to the left until the tilting frame 52, 53in engagement with the ring 57 over the disc 54 and the sleeve portion 50 is in the second end position shown in Fig. 4. As soon as the ring 57 has passed over its middle position (Fig. 6) it slides with the bolts 56 in the radial slots 55 of the disc 54 downwardly to the'left into the end'position shown in Fig. 7, whereby the nose 60 is disengaged from the mentioned notch 62 of the ratchet wheel 61. As obviously there is no absolute guarantee for this downward sliding of the ring 57 under the influence of its own weight only, the abutting ledge 59 is provided. During the afore-mentioned rotation of the winding shaft 2 in a counterclockwise direction the projection 58 of the'ring 57, which is at the lower portion thereof in Fig. 5, moves upwardly and, if the ring does not fall under its own weight, abuts against the chamfered surface 59a of the mentioned abutting ledge so that upon further rotation of the winding shaft 2 the ring 57 is forced into the position shown in Fig. 7, thus releasing the coupling engagement between the winding shaft 2 and the tilting frame 52, 53. Upon further'rotation of the winding shaft 2 the blind is raised.

Owing to the excentrical arrangement of the tilting frame 52, 53 an additional resistance must be overcome when the tilting frame is pivoted from its end position according to Fig. 2 into its middle position according to Fig. 3. This additional resistance helps in assuring an efficient locking of the tilting frame in the mentioned end position. Furthermore this excentrical arrangement of the tilting frame supports the pivoting of the frame from itsmiddle position shown in Fig. 3 into its'otherend position accordingto Fig. 4.

if, with the different elements of the blind in the position shown in Fig. 7, the winding shaft 2 is rotated in a clockwise direction a projection 62 of the ratchet wheel 61, entrained by this rotation, is engaged by the uppermost no'se 60 of the ring 57 and imparts a tilting movement to the frame 52, 53, which returns into the position shown in Figs. 6 and 7 respectively, in which the ring 57 is forced into the position'shown in Fig. 7 'by the'abutting ledge 59 in combination with its own weight. Further rotation of the'winding shaft 2 results in a loweringof the blind.

In the second embodiment represented in Figs. 8-12 of the accompanying drawings a tilting frame 72, 73 is pivotally mounted on each of the two end portions of the winding shaft 2 by means of two sleeve portions 70, having each a square block 71 at the end facing the other sleeve portion. The lateral parts 72 of each tilting frame are rigidly mounted on the associated square block 71, while one end of the two ladder tapes 8 for the laths 9 is 'laid'onto the bent sheet metal portion 73 of the tilting Cir frame and secured in a not represented manner to this piece 73. The tilting frame 72, 73 is arranged on the sleeve portions in such a way that the axis of the partly cylindrical sheet metal piece 73 is excentrical with respect to the axis of the winding shaft 2, namely, when compared with the middle position of the tilting frame as shown in Fig. 10 (whereby the outer side of the blind is on the right hand side in the figure), displaced to a small amount outwardly and to a larger extent downwardly. Thus in this embodiment too, the tilting frame 72, 73 is unstable in its middle position. In both end positions illustrated in Figs. 9 and 11, which, on the one hand are given by the corresponding closing position of the laths but'which, on the other hand could also be limited by not represented abutments co-operating with the tilting frame, the tilting frame is stable. The ladder members 8, represented in Fig. 8 as narrow tapes, traverse the bottom of the casing 1 through transverse slots 10. The laths are held by bridges 11 provided between the two ladder members'S.

The Winding shaft2 is supported by means of the two sleeve poi'tions 70 on transverse supports 17 secured to the casin 1.

-"A"dis'c"54 is mounted on the sleeve portion 70 situated at the side of the tilting frame 72, 73 facing the corresponding'e'nd of the winding shaft 2. A follower ring 57 is arranged at this disc so as to be radially movable by means of screws 56 projecting through radial slots 55 in the disc, as already described with request to the first embodiment. Arrangement and operation of the ratchet and pawl device 54--62 are the same as for thefirst described embodiment.

The ratchet and pawl device permits coupling of the tilting frame with the winding shaft over a half revolution of the latter. This is particularly advantageous as it is well known that for changing the laths from one end position to the other end position a certain length of the ladder tapes 8 must be unwound from or wound onto the sheet'metal piece 73. As this length is given for each-particular blind, it is necessary in order to obtain the required length of tape, to have a diameter of the partly cylindrical tilting frame 72, 73, which is the greater the smaller the maximum angle is, about which the tilting-fram'e may be pivoted by the ratchet and pawl device 5462. In most of the heretofore known devices the winding drum for the pull member is arranged within the tilting frame and for this reason the latter is usually rather great. Thus even for small tilting angles of or less there is always a sutficient length remaining for the ladder tapes to be unwound.

This is not the case in the present embodiment. Here the winding drum 13 is not arranged within the tilting frame 72, 73 but at the outside thereof. It is rigidly mounted on the winding shaft 2 between the ratchet and pawl device 5462 and the corresponding end of the shaft 2. The drum 13 is provided in a known way with a peripheral groove 13a on the bottom of which is fastened one end of the pull tape 12 so that the said tape may be wound about the drum 13 by rotation of the shaft 2. The pull tape 12 passes through slots 9a in the laths 9 and is attached to the lowermost lath in a not represented but well-known manner. As visible from Fig. 1 the drum 13 and the pull tape 12 and thus also the slots 9a in the laths are arranged in such a way that they are beyond the surface of the blind covering the window and indicated by the dotted line a. Thus even with the blind closed no light penetrates through the slots 9a.

As already mentioned and as is visible from the Figs. 9-ll the ratchet and pawl device provided here permits a tilting of the tilting frame about i. e. about a substantially larger angle than is obtainable with heretofore known blinds. As moreover no winding drum is in the way, the diameter of the tilting frame can be made as small as desired, so that it is possible to pronecessary to cover, by the ladder tapes 8, the slots 9a in the laths 9, through which light may penetrate, the ladder tapes may-also be replaced by simple ropes 80 as shown in the variant illustrated in Fig. 12. In the blind shown in this Fig. 12 the window surface a to be covered attains laterally almost the ends of the laths so that the provision of. slots 9a for the pull tape 12 is not desirable in this particular case. Therefore the laths 9 are guided in vertical guide rails 82 by means of loops 81 provided at the laths. The not represented winding drum is secured on the winding shaft 2 at such a point that the pull tape 12 extends throughthe said loops 81 to the lowermost laths 9.

The tilting frame 72, 73 is removably arranged on the sleeve portions 70. This greatly facilitates the assembling and taking to pieces of the blind.

Instead of arranging the tilting frame excentrically with respect to the winding shaft the same effect may be obtained by adapting a small weight with its centre of gravity at the outside of theaxis of the sleeve on one of the sleeve portions carrying the tilting frames.

I claim:

1. In a Venetian blind'of the type having a winding shaft, tilting frames pivoted thereon, ladder members suspended from the said tilting frames and laths carried by the said ladder members and adjustable by tilting of the said tilting-frames, winding drums mounted on the .said Winding shaft, pull members attached to the lowermost lath and each windable around one of the said windingdrums for raising and lowering the blind, the provision of a ratchet and pawl device, comprising a ratchet wheel rigidly mounted on the said windingshaft, a follower ring in driving connection with a tilting frame -'and radially movable to a limited extent, two noses provided in. a substantially diametrically opposed arfrangement on one surface of the said follower ring,

one of the said noses being adapted to co-operate over a 7 part of a revolution of the winding shaft with the ratchet wheel when the winding shaft is operated to lower the blind and the other of the said noses being adapted to co-operate over a part of a revolution of the winding shaft with the ratchet wheel when theshaft is operated to raise the blind forpivoting the tilting frame and adjusting the laths. 2. A Venetian blind comprising a winding shaft, sleeve 7 portions arranged on the said shaft, tilting frames of partly cylindrical shape' arranged eccentrically with respect to the winding shaft and each supported on two of the said sleeve portions, ladder members suspended from said tilting frames and laths carried by the said ladder members and adjustable by tilting of the said tilting frames, winding drums mounted on the said winding shaft, pull members attached to the lowermost lath and each windable around one of the said winding drums for the raising and lowering of the blind, a ratchet and pawl device comprising a disc secured to one of the said two sleeve portions associated with each tilting frame, a

' one surface of the said follower ring, said disc having two screws co-operating over a part of a revolution of the Winding shaft with the slots in the disc when the wind .ring for cooperation with the said chamfered surfaces of a revolution 'of the winding shaft with the slots in the pivoting the tilting frames and adjusting the laths.

ring, said disc having two slots provided in diametrically opposed arrangement adapted to receive and guide the noses formed by the screws secured to the follower ring, one of the said screws co-operating over a part of a revolution of the winding shaft with the slots in the disc when the winding shaft is operated to lower the blind and the other of the said screws being adapted to cooperate over apart of a revolution of the winding shaft with the slots in the disc when the shaft is operated to raise the blind for pivoting the tilting frames and adjusting the laths.

3. A Venetianblind comprising a winding shaft, sleeve portions arranged on the said shaft, tilting frames of partly cylindrical shape arranged eccentrically with respect to the Winding shaft and each supported on two of the said sleeve portions, ladder members suspended from the said tilting frames and laths carried by the said ladder members and adjustable by tilting of the said tilting frames, winding drums mounted on the said winding shaft, pull members attached to the lowermost lath and each windable around one of the said winding drums for the raising and lowering of the blind, a ratchet and pawl device comprising a disc secured to one of the said two sleeve portions associated with each tilting frame, a casing surrounding the winding shaft, abutting ledges secured to that casing, chamfered surfaces provided on the said abutting ledges, a follower ring in driving connection with a tilting frame and radially movable to a limited extent, projections on the periphery of the said follower of the abutting ledges, screws secured in the said follower ring and projecting beyond one surface of the latter to provide two substantially diametrically opposed noses on slots provided in diametrically opposed arrangement adapted to receive and guide the noses'formed by the screws secured to the follower ring, one of the said ing shaft is operated to lower the blind and the other of the said screws being adapted tom-operate over a part disc when the shaft is operated to raise the blind for References Cited in the file ,of this patent UNITED STATES PATENTS

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