Description:
BACKGROUND OF THE INVENTION
The invention relates to Venetian blinds and other blinds, the term "blind" designating a device such as is used in connection with an opening to keep out light or hinder vision.
Venetian blinds and various other blinds are customarily provided with lift cords which pass through a cord lock and hang down to be pulled downwardly and eased upwardly to raise and lower the blind. In passing through the cord lock the lift cords ordinarily make a 90° bend around a cord guide that is included in the cord lock. In spaced relation to such cord guide there is locking means that is adapted to make locking engagement with the lift cords and clamp them against the aforesaid cord guide. Typically, the locking means is a locking dog which is so pivoted that it has unbalanced weight which biases the dog away from the lift cords.
The blind having been raised or lowered to the desired degree, the down-hanging lift-cords are swung sidewise against the locking dog (usually provided with teeth which the cords engage) and then the lift cords are eased upwardly for a short distance. The lift cords, by reason of their engagement with the locking dog, move the nose of the dog upwardly --thereby causing the dog to swing in the direction of the lift cords and clamp them against the cord guide around which the cords make the 90° bend. When the blind is to be raised or lowered to a different position, the down-hanging lift-cords are first pulled downwardly for a short distance; this releases the locking dog which, by reason of its unbalanced weight, swings away from the lift cords.
Because actuating the cord lock involves easing the lift cords upwardly for a short distance, it is likely to be troublesome to so manipulate the lift cords that the locking will be completed with the blind at the exact level that may be desired. Further, the weight of the raised portion of the blind is a factor in the locking action of the locking dog. This tends to make the locking action uncertain when the weight of the raised portion of the blind is quite small, as when the blind is quite light in weight or when only a small portion of the blind is raised.
United States patent to Kuyper U.S. Pat. No. 1,957,272 shows in its FIGS. 8, 6, 9 and 1 a Venetian blind in which a separate actuating cord is connected to the locking dog of the cord lock; when the actuating cord is pulled the locking dog is swung into engagement with the lift cords, clamping them against the top of the cord-lock housing. In the Kuyper blind there is wide separation between the down-hanging lift cords and the actuating cord for the cord lock, which separation Kuyper needs for protection against entanglement between the lift cords and the actuating cord. In various installations this wide separation is undesirable. Further, Kuyper's cord lock requires more space than is desirable in many instances. Still further, Kuyper's blind has difficulties in connection with the weight that is imposed upon the locking dog. To prevent false operation of his locking dog, the combined weight of Kuyper's actuating cord and pull tassel will have to be severely limited. Additionally, there is the problem of variations in the weight of the actuating cord, due to the varying length thereof in different installations.
SUMMARY OF THE INVENTION
The present invention provides a blind in which there is pendant cord-guide means for the lift cords, such cord-guide means being attached to and being carried by an actuating cord that is connected to the locking means of the cord lock.
In accordance with features afforded by the invention:
(a) the down-hanging lift-cords pass vertically through spaced lift-cord passages in the pendant cord-guide means; (b) collectively, the lift-cord passages are adapted to receive two or more lift cords; (c) the attachment of the cord-lock actuating-cord to the pendant cord-guide means is at a location that is between the spaced lift-cord passages, the lift-cord passages being symmetrically arranged in relation to such attachment; (d) the lift-cord passages extend vertically for a distance which is long as compared to the thickness of the lift cords; (e) the lift-cord passages afford unfettered movement of the lift cords through the passages; (f) the pendant cord-guide means is a unitary cord-guide which has it central vertical-axis passing through its center of gravity, and it is on such vertical axis and above the center of gravity that the pendant cord-guide is attached to the cord-lock actuating-cord; (g) the pendant cord-guide is a pendant block, and the central vertical-axis of the block is aligned at least approximately with the cord-lock actuating-cord; (h) the cord lock has a pivoted locking-dog which is spring biased away from the lift cords, the spring having sufficient strength to counteract the combined weight of the pendant cord-guide and the cord-lock actuating-cord; (i) the spring is a readily detachable and replaceable coil spring; and (j) the cord-lock actuating-cord, adjacent to the locking-dog-connected end thereof, is formed into a bight which embraces the pivot of the locking dog.
The invention affords all of the foregoing features, among others. It is left to the user to select the features which are needed or desirable for his particular use.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a largely diagrammatic front elevation, with parts broken away, showing a blind embodying the invention. In this instance the blind is a Venetian blind.
FIG. 2 is a largely diagrammatic detail view in sectional elevation with parts omitted and parts broken away, the view being to a larger scale than FIG. 1. FIG. 2 shows the interior construction of the cord lock and shows two lift cords passing through the cord lock, the dog of the cord lock being in unlocked position. FIG. 2 also shows, in vertical front-to-rear section, the block which constitutes the pendant cord-guide; and to afford the front-to-rear section, the block in FIG. 2 is rotated 90° on its vertical axis from the position in which the block is shown in FIG. 1.
FIG. 3 is a top plan view of the cord lock itself, to the same scale as FIG. 2, the locking dog being in unlocked position. Fragments of the cords and an attaching eyelet for the cord lock are shown also.
FIG. 4 is the same as FIG. 2 but with the locking dog in locked position.
FIG. 5 is a central vertical-section of the block which constitutes the pendant cord-guide, the plane of the section being parallel to the expanse of the blind in FIG. 1 and being perpendicular to the sectional plane of the block in FIGS. 2 and 4. Fragments of two lift cords and a fragment of the cord-lock actuating-cord are shown in elevation.
FIG. 6 is the same type of view as FIG. 5 but showing a pendant cord-guide block having four separate lift-cord passages. Fragments of four lift-cords and a fragment of the cord-lock actuating-cord are shown in elevation.
FIG. 7 is a perspective view, on an enlarged scale as compared to FIGS. 2-4, showing the locking dog that is shown in FIGS. 2-4
FIG. 8 is a perspective view, corresponding to FIG. 7, showing enough of the locking dog to illustrate how it may be modified to provide teeth which will engage the lift cords when the locking dog is in locked position.
FIG. 9 is the same as FIG. 5 but showing four lift cords, instead of two.
DESCRIPTION OF THE EMBODIMENTS THAT ARE PRESENTLY PREFERRED
The best modes thus far contemplated of carrying out the invention are herein disclosed. Nevertheless, the disclosed modes are by way of illustration and example, since other modes may be used; and the claims embrace other modes. Except as otherwise indicated the description hereinafter (prior to the claims) is of the particular forms of the invention that are shown in the drawing and does not necessarily refer to any other form. The above heading is not to be considered as applying to the claims, no matter what style and/or format is used in printing the patent.
In FIG. 1 the Venetian blind is designated as a whole by B. It has a conventional ladder-and-slat assembly 10, which is conventionally suspended beneath a head 11 that is conventional except for the cord lock that is shown in FIGS. 2-4. A conventional bottom bar 12 acts as the lowermost slat of the ladder-and-slat assembly 10. Two lift cords 14 and 15 are connected to the bottom bar 12, from which they proceed as follows:
upwardly through conventional openings (not shown) in the conventional slats 16, into the head 11 in conventional manner, thence to the right within the head in conventional manner, through the cord lock in conventional manner, hanging down as shown in front of the slats and passing through a pendant cord-guide CG, and then being attached in conventional manner to a conventional tassel 17. The two lift cords hang down as shown to be pulled downwardly and eased upwardly to raise and lower the slats of the blind, commonly referred to as raising and lowering the blind. In FIG. 1 the portion RP is in raised position. The two lift cords 14 and 15 may be two branches of a single length of cord which is folded back upon itself, having a bight within the tassel 17.
The head 11 includes a conventional sheet-steel channel 20 (FIG. 1) which, as shown in FIGS. 2 and 4, has a bottom wall 21, a front wall 22 and a rear wall 23. Nested within the channel 20 and located toward the right-hand end of the channel there is a cord lock which is designated as a whole by CL. The cord lock has a body 30 which is stamped in one piece from sheet steel, the body having a two-part bottom wall 31a, 31b, a front wall 32 and a rear wall 33. In the bottom wall 31a, 31b there is a rectangular opening 36 which extends from one bottom-wall part 31a to the other bottom wall part 31b and from the front wall 32 to the rear wall 33. The bottom wall 31a, 31b of the cord-lock body is against the bottom wall 21 of the head channel 20, and is suitably secured thereto as by one or more eyelets or rivets 38 (one shown). In the bottom wall 21 of the head channel 20 there is an opening 26 (FIGS. 2 and 4) which is the same size as, and registers with, the opening 36 in the bottom wall of the cord-lock body 30.
In forming the cord-lock body 30, metal taken from the opening 36 in the bottom of the body is formed into a hollow cylindrical cord-guide 39 which extends from the front wall 32 of the cord-lock body to the rear wall 33 of the cord-lock body, the axis of the cylindrical formation being horizontal and being perpendicular to the walls 32 and 33. The cord guide 39 guides the lift cords 14 and 15 through a 90° bend, from horizontal to vertical. The lift cords pass through the openings 36 and 26 and hang down from the cord lock; see FIGS. 2-4.
The cord lock CL includes a movable locking-dog which is designated as a whole by D (FIG. 7), this dog being adapted to lock the lift cords 14 and 15. The dog D is stamped in one piece from sheet steel; it includes front and rear cheeks 42 and 43, front cheek 42 loosely engaging the front wall 32 of the cord-lock body and the rear cheek 43 loosely engaging the rear wall 33 of the cord-lock body. The dog D is pivotally mounted in the cord-lock body by means of a rivet 45, which constitutes a pivot and is located as shown in FIGS. 2-4. The rivet 45 passes through the front and rear walls 32 and 33 of the cord-lock body. The rivet 45 also passes through and makes a loose bearing-fit with the locking-dog cheeks 42 and 43 at the openings 42a and 43a thereof. The cheeks 42 and 43 are connected together by a U-shaped formation which includes planar legs 46 and 47 that are in spaced parallel relation, the leg 46 being somewhat shorter than the leg 47. The legs 46 and 47 lie on opposite sides of, and are equidistant from, a plane which includes the pivotal axis of the dog D and is parallel to the legs 46 and 47. The legs 46 and 47, which are connected together by an arc as shown, have free ends 48 and 49 that engage the lift cords 14 and 15 when the locking dog swings into locking engagement with the lift cords and clamps them against the cylindrical cord-guide 39; see FIG. 4. In the modified locking dog D' that is shown fragmentarily in FIG. 8 the legs 46 and 47 are provided with serrated free ends 48' and 49', whereby the dog has teeth which engage the lift cords when the dog is in locked position.
The rear cheek 43 of the locking dog is notched at 43a, and one end of a coil spring 50 is connected to the notch as is seen in FIGS. 2-4. The other end of the coil spring 50 is connected to a finger 33a which is struck from the rear wall 33 of the cord-lock body. The spring 50 biases the locking dog away from the lift cords 14 and 15 and into the position shown in FIG. 2, counter-clockwise movement of the locking dog being arrested by finger 33b (FIGS. 3 and 4) which is struck from the rear wall 33 of the cord-lock body adjacent to the bottom of the rear wall. The locking dog (D or D') is swung into locking position by means of an actuating cord 51 which is connected at its upper end to the locking dog and from which it hangs down through openings 36 and 26. Adjacent to its upper end the actuating cord 51 is formed into a bight which embraces the pivot 45 of the locking dog, the cord being connected to the locking dog by passing through the hole 44 (FIGS. 7 and 8) and being knotted at 51a as is shown in FIGS. 2 and 4. When the actuating cord 51 is pulled it overcomes the bias of the spring 50, swings the locking dog clockwise as viewed in FIGS. 2 and 4, and brings the locking dog into locking engagement with the lift cords 14 and 15 as shown in FIG. 4. The arrangement of the actuating cord in a bight which embraces the pivot of the locking dog is a very compact arrangement and, nevertheless, affords large angular movement of the locking dog when the actuating cord is pulled.
The down-hanging lift-cords 14 and 15 are guided by the pendant cord-guide CG, which may be a pendant block of suitable size and shape and which is made of suitable material. The block CG that is shown has a height h, a width w, a thickness t, a top 60, a bottom 61, a generally planar front-face 62, a generally planar rear-face 63, a generally planar right edge-face 64, and a generally planar left edge-face 65. The various corners of the block are rounded off somewhat. The block CG that is shown is molded in one piece of suitable plastic --plastic which is hard, impact resistant and light in weight being presently preferred. If desired, the plastic may be translucent or transparent.
The block CG is symmetrical about its vertical axis, which is midway between the front and rear faces 62 and 63 and also midway between the right and left edge-faces 64 and 65. The center of gravity of the block CG is on its vertical axis, being a trifle above the level that is midway between the top 60 and the bottom 61. Near the top of the block CG, and coaxial with the vertical axis of the block, there is a short vertical bore 68 of relatively small diameter. Above the bore 68 there is a short counterbore 69 leading to the top of the block, and below the bore 68 there is a long counterbore 70 leading to the bottom of the block. As shown in FIG. 5, there are vertical bores 71 and 72 which are equally spaced in opposite directions from the bore 68 and its companion counterbores 69 and 70. The bores 71 and 72 extend for the entire height of the block CG, the axes of these two bores being parallel to the vertical axis of the block and being midway between the front and rear faces 62 and 63 of the block.
The pendant block CG is attached to and carried by the actuating cord 51 that is connected to the locking dog of the cord lock CL. The vertical axis of the block CG is in at least approximate alignment with the actuating cord 51, the offset between the lower and upper fragments of the cord 51 in FIGS. 2 and 3 being due to the break out between these two fragments. The attachment of the block, CG to the cord 51 is by virtue of the lower end of the cord 51 being threaded through the bore 68 and being knotted as shown in FIG. 5, the knot 51a being drawn into the counterbore 70 and to the top of the counterbore as is shown in FIG. 5. It will be seen that the block CG is not only attached to the cord 51 at a location that is on the vertical axis of the block CG but the attachment is located at a level which is substantially above the center of gravity of the block CG --whereby the weight of the block biases it into untilted position.
The down-hanging lift-cords 14 and 15 pass vertically and individually through the bores 71 and 72, whereby the lift cords are guided by the pendant block CG. The bores 71 and 72 are cylindrical and have equal diameters. The bore diameter is substantially in excess of the lift-cord diameter, the relative diameters of the bores 71 and 72 and the lift cords 14 and 15 being as shown in FIG. 5. Thus, the bores 71 and 72 afford unfettered longitudinal (vertical) movement of the lift cords through the bores. The bores 71 and 72 have the same length, each of these bores extending vertically for a distance which is long as compared to the thickness of the lift cord, whereby the block CG affords effective guiding of the lift cords 14 and 15 and inhibits entanglement between the lift cords and the actuating cord 51. The bores 71 and 72, while being long compared to the thickness of the lift cords, are long as compared to the diameter of the bores, the relative dimensions being as shown in FIGS. 2, 4 and 5.
The pendant cord-guide block CG doubles as a tassel for pulling the cord 51 to actuate the cord lock. The coil spring 50 of the cord lock may be an initially-set spring, i.e., a spring that is so coiled in known manner that the convolutions are biased against one another, so that the spring doesn't start to extend until a predetermined tensioning force has been applied to the spring. Such a spring, with appropriate initial set, will completely counteract the weight of the actuating cord 51 plus the weight of the pendant block CG, thereby insuring against false operation of the locking dog of the cord lock. The length, and consequent weight, of the actuating cord 51 will be greater in some blinds than in others. Also, some pendant cord-guides will be heavier than others, due to being made of different material or due to being of different size, or both. For example, the pendant cord-guide CG' of FIG. 6 (to be described presemtly) is heavier than the pendant cord-guide CG. Thus, in different installations, the spring 50 will be called upon to compensate for different total weights of actuating cord and pendant cord-guide. The spring 50 has hook ends which are hooked to the finger 33a and the notch 43a. These spring ends are easily unhooked and rehooked, thereby rendering the spring 50 readily detachable and replaceable. Thus, a suitable spring 50 can be selected and used for any particular installation.
While two is probably the most-frequently-used number of lift cords, there is no particular limit to the number of lift cords that a blind may have. Four lift cords are not uncommon, six have been used, and any number larger than six is rare. An odd number of lift cords has been used, but only rarely.
The lift cords are circular in cross section, as are the lift-cord passages in the pendant cord-guide. As shown in FIGS. 2, 4, 5 and 9 the lift-cord passages 71 and 72 each have a diameter that is approximately three times the lift-cord diameter, whereby these passages have a cross-sectional area that is approximately nine times the lift-cord cross-sectional area. Accordingly, the guide block CG is suitable for any likely number of lift cords. With an eight-lift-cord blind four lift cords can be placed in each of the passages 71 and 72, with unfettered longitudinal movement of the lift cords through the passages. In the case of an odd number of lift cords, one of the passages 71 and 72 would have one more lift cord than the other. But with an even number of lift cords, which is the usual case, an equal number of lift cords is in each of the passages 71 and 72, these two passages being on opposite sides of the actuating cord 51 and equidistant therefrom. FIG. 9 shows the guide block CG used with a blind having four lift cords 14, 14', 15 and 15' --a group of two of the lift cords being placed in each of the passages 71 and 72.
FIG. 6 shows a modified guide block CG' used with a blind having the four lift cords 14, 14', 15 and 15'. The block CG' has four lift-cord passages 71a, 71b, 72a and 72b that are individual to the four lift cords. Each of the four lift-cord passages is cylindrical and has a diameter which is only a little larger than the lift-cord diameter, but enough larger to afford unfettered longitudinal movement of the lift cord through the passage. The amount of material that is elimiated from the guide block in forming one of the cylindrical cord-guide passages is proportional to the square of the diameter of the passage. Hence, less material is eliminated in forming the four cylindrical lift-cord passages of FIG. 6 than in forming the two cylindrical lift-cord passages of FIGS. 5 and 9; and guide block CG', which has the same over-all dimensions as guide block CG and is made of the same material, weighs somewhat more than guide block CG.
As will be apparent from FIG. 3, four lift cords may be used with the cord lock CL. The space between the front and rear walls 32 and 33 of the cord lock body, and the front-to-rear dimensions of the locking dog D and the cylindrical cord-guide 39, are sufficient to enable the cord lock to take care of two more lift cords. The two additional lift cords are placed between the rear wall 33 and the lift cord 15 that is shown in FIG. 3. Where the blind has more than four lift cords, but not over eight, two cord locks CL may be used. The two cord locks are placed one immediately behind the other in the head channel 20 and secured in like manner to the bottom 21 of the head channel. The lift cords are suitably divided between the two cord locks.
Regardless of the number of lift cords, the down-hanging ends of the cords are united at a tassel 17 or the like. The tassel 17 may be replaced by a duplicate of the pendant cord-guide block CG, the lift cords being passed through the passages 71 and 72 thereof and being united immediately beneath the duplicate block CG. If desired, the duplicate block CG may have the walls of the counterbore 70 removed for a distance up from the bottom of the block, thereby providing the block with an internal space to receive the fastened-together lift-cord ends.