US2559928A - Tilting device for venetian blinds - Google Patents

Description

July l0, 1951 J. c. BENNETT TILTING DEVICE FOR VENETIAN BLINDs 2 Sheets-Sheet 1 Filed Feb. '7, 1948 JNVENTOR. Yymvgeue B s f 63M@ a., w

firme/vg? July 10, 1951 J. c. BENNETT 2,559,928

TILTING DEVICE FOR VENETIAN BLINDS Filed Feb. '7, 1948 2 Sheets-Sheet 2 INVENTOR.

MyW-5M (mm-UM Patented July 10, 1951 TIL'IIN G DEVICE1 FOR VENETIAN BLIN DS JamesC. Bennett, Inglewood, Calif., assignor `to Anderson Die Casting `& Engineering Corporation, Los Angeles, Calif., a corporation ofCalifornia Application February 7, 1948, Serial No. 6,830

12 Claims. l

This invention relates generally to Venetian blinds and more particularly to a novel and improvedtiltingmechanism for such blinds.

Tilting mechanisms for Venetian blinds-usually include' a self-locking worm gear'train, the driven Worm wheel being operatively connected to the tiltable head rail from which theslats of the blind are suspended,V and the driving Worm gear being operatively connected to a pulley. An operating cordvextends ov-er'the pulley, the ends of the cordtextending downwardly to Within convenient reach of the operator. By pulling downwardly on one or the other end of the cord, the pulley may be rotated in either direction, the rotation of the pulley being transmitted through the worm gearingto tilt the head rail and thus adjust the slats of the-blind.

A difculty inherent in Venetian blind tiltingr mechanisms which :depend on a friction drive between the operating cord and the pulley is the tendencyifor the cord to slip on the pulley. This slippage is usually not uniform in bothy directions of.v operation; and hence the cumulative slippage from repeated adjustments of the slats results in the depending portions of 'the cord beingof widely divergentlengths. If this condition is. not corrected: periodically, it eventually interferes with the tilting operation. by engagement of the knob on the short end of the cord with the pulley beforev the maximum or thevdesired amount of tilting has been eiiected.v

' I am aware that attempts have previously been made to overcomeY the foregoing diiiiculty by incorporating inthe tilting mechanism a releasabledriving connection between the pulley and the Worm gear, the pulley being de-clutchedfrom theworm gear by manipulation oibothends of the kcord as a unit in a particular manner, .Whereupon thepulley mayV be rotatedl to equalize the cordlengths without effecting tilting oiJthe slats. In one suchdevice the depending portions-,ofthe cord are swungoutwardly in a direction normal to .the plane ofthe blind tor releasexthe driving connection. In another construction the depending portionsof the cord areswung ina direction parallel to the plane of the blind-,about the axis of th-e pulley. The latter type olers greater convenience of operation'and also imposes lessstrain on the mechanism than the first-mentioned type. However, the last-mentioned type as heretofore constructed` has Ibeen diiiicult and expensive to manufacture because of the number and intricacy-of the parts.

It is a principal object of this invention to provide a tilting mechanism for` Venetian blinds incorporating an improved and simplified releasable drive connection efl'ective, upon arcuate movement of the depending portions of the cord in a direction parallel to the plane of the blind, to permit equalizing adjustment of the cord lengths.

Another object of the instant invention is to provide a tilting mechanism-of the foregoingtype embodying a minimum number of parts of simple but rugged construction, wherebyA economy of manufacture and durability in use are attained.

A further object of this invention is to provide a slat tiltingY mechanism wherein substantially all Vof the parts are so Vdesignedasto lend themselves readily to' economic production by the die casting process.

A still further object of this invention is tov provide a slat tilting mechanism embodying cordequalizng adjustment means which is positive rin action and capable of long, trouble-free service life. V

Other and further objects will be apparent from the following detailedfdescription of a preferred embodiment of the invention, reference being had to the accompanying drawings, wherein:

Figure 1 is a front elevation of a Venetian blind incorporating the tilting mechanismor this-in.- vention;

Figure 2 is a View taken on line 2 2of Figure 1showing the tilting mechanism in side elevation;

Figure 3 is a vertical sectional view takenon line 3 3 of Figure 2;

Figure 4 is a vertical sectional view taken on line 4 4 of Figure 3showing the pulleyr and Worm gearing operatively connected Figure 5 is a View similar to Figure 4 but showing the driving connection in released position;

Figure 6 is a transverse sectional. View. taken on line 6 6 of Figure 4 Figure 7 is a transverse sectional view taken` on line 1 1 of Figure 5;

Figure 8 is a view taken on line 8 8 otFigure 4;,and

Figure 9 is view taken on line 9 9 of Figure .4.

A tilting mechanism embodying the instant invention is particularly adapted to be applied to a Venetian blind such as that illustrated inFigure 1 of the drawings. As shown therein, the blind comprises a head rail I from which the usual slats 2 are suspended by ladder Jtapes 3, the lat.- ter being attached to opposite edges of the head rail and supportingthe vslats in such manner as tov cause the slats to tilt in unison-With the head rail. The head rail is supported by a frame 4 for tilting movement relative thereto about its central longitudinal axis, and for this purpose one end of the head rail is provided with a trunhion journaled in a bracket 5 attached to the frame 4 and incorporating the usual mechanism associated with the raising cord 6. The other end of the head rail is provided with a drive boss 1 of noncircular configuration, herein shown as square, which is received in a socket 8 in the tilting mechanism, generallyvdesignated I8. As shown in Figures 2, 4 and 5, the socket y8 is noncircular and is preferably provided with internal serrations l l, four of which engage the corners of the boss 1 to provide a driving connection therewith, in addition to supporting the adjacent end of the head rail.

The tilting mechanism I3 comprises a gear train including a worm wheel I2 in lwhichthe socket 8 is formed, the worm wheel meshing with a worm I3 journaled on a shaft I4, on one end of which is secured a pulley I5 over which is trained the bight of an operating cord I6. The shaft I4 and worm gearing I2, I3 are housed within and supported by a housing comprising a pair of mating housing members I1 and |18, as best shown in Figure 3. Studs I9 formed on the member I1 are received in corresponding holes in the member I8, the ends of the studs being upset, as shown at in Figure 6, to retain the housing members in assembled relation. The housing members are provided with flanges 2i and 22 which are bored to receive screws 23 or the like for attaching the housing to the frame 4. As shown in Figure 3, the lower portions of the housing members I1 and I8 are provided with aligned bores 24 and 25 in which the hubs 25 and 21 ofthe worm wheel I2 are journaled. Each hub is provided with an internally serrated socket 8, thus permitting the installation of the f tilting mechanism I0 at either end of a head frail l..

The worm I3 is journaled on the shaft I4 and, as described hereinafter, is normally connected ,in driving relation with the shaft by clutch means which is releasable at will to permitrotation .of the shaft relative to the worm. Reactive end `thrust of the worm is absorbed by opposed abutments 38 and 3l on the housing members. As -;best Shown in Figure 3, a pair of inward projections 32 and 33 are formed on the inner walls of the housing members, at least the inner ex- :tremities of the projections having a close running clearance with the outer surface of the threads of the worm I3. The function of these projections is to absorb the upward reactive thrust imposed on the worm by the worm wheel.

"The clearance between the shaft I4 and the bore of the worm is greater than the clearance between the worm `threads and the projections 32 and 33, and hence the upward thrust is absorbed by the projections rather than being transmitted to the shaft I4. f

'L Referring now to thereleasable driving connection between the shaft I4 and the worm I3, it will be observed that the shaft is provided with an enlarged inner end 35 which is journaled in a pocket 36 formed in the housing members. Clutch teeth 31 are formed on the shaft adjacent itsjunctureA with the enlarged end 35, and mating clutch teeth 3B are formed on the adjacent end of the worm I3, the form of the clutch teeth being best shown in Figure 8. The depth of the Xpocket 36v exceeds the axial dimension of the enlarged shaft end 35 by an amount slightly greater than the axial dimension of the clutch teeth 31, thus permitting axial movement of the shaft between the clutched position shown in Figure 4 and the ie-clutched position shown in Figure 5. The shaft is normally yieldingly retained in its clutched position by a compression spring 39 interposed between the adjacent inner wall ofthe housing I1, I8' and the base of a recess 48 formed in the shaft.

Movement of the shaft I4 to the right, as viewed in Figures 4 andl 5, into its de-clutched position is effected by a. cam sleeve 42 journaled on a reduced section of the shaft. The cam sleeve is journaled in a bearing bore 43 in the housing, and abuts a shoulder 44 on the shaft. As best shown in Figures 4 and 1, the outer surface of the cam sleeve is out away at diametrically opposite sides thereof to form a pair of segmental pockets 45 and 46, each extending from the outer end of the sleeve and terminating in a double cam surface consisting of oppositely inclined cam surfaces 41 and 48 joining each other at 49 and terminating in short circumferentially extending surfaces 58 and 58a. A pair of lugs 5I and 52 project inwardly from the housing members I1 and I8 into the pockets 45 and 46 and, as shown in Figures 4 and 6, are normally disposed at the inner extremities of the 'pockets adjacent the juncture of the cam surfaces 41 and 48. Upon rotation of the cam sleeve 42 in either direction, the engagement of the cam surfaces 41 or 48, depending on the direction of rotation of the sleeve, with the lugs 5I and 52 forces the cam sleeve inwardly, and, by virtue of the abutment of the sleeve against the shoulder 44 on the shaft I4,.the shaft is moved inwardly to disengage the clutch teeth 31 and 38. When the sleeve is rotated into the position shown in Figure 5, the lugs engage the circumferentially extending terminal portions 49 or 58 of the cam surfaces. It will be apparent that in this position, because of the disposition of the surfaces 49 and 58, the axial force exerted by the spring 39 tending to return the shaft and sleeve to their original position does not tend to effect reverse rotation of the cam sleeve, such as would be the case if the surfaces 49 and 58 were omitted and the cam surfaces 41 and 48 continued to the side walls of the pockets 45 and 46.

A cord guard or fair-lead, generally designated 55, is freely rotatable on the shaft I4 between the cam sleeve 42 and the pulley I5. The guard includes a hub portion 56 from which depends an L-shaped portion, the base 51 of which underlies the pulleyand carries at its outer extremity an arcuate guard portion 58. Lugs 59 and 68 formed on the extremities of the guard portion 58 cooperate with the base portion 51 to define a pair of fair-lead passages 6I and 62 Within which the cord I6 is confined to retain it in the groove of the pulley.

In order to effect rotation of the cam sleeve 42 by the guard member 55, a pair of segmental projections are formed on the hub portion 56 of thev guard member, one of these projections being shown at E5 in Figure 4. These projections are received in the pockets 45 and 4B to provide a driving connection between the guard member and the cam sleeve, whereby upon rotation of the guard member from its normal central position shown in Figure 6 to the position shown in Figure '1, the cam sleeve 42 is similarly rotated to effect axial movement of the shaft I4 and consequent disengagement of the clutch teeth 31 and 38.

The pulley I may, if desired, be of conventional construction, but for convenience of manufacture it is preferable that it be made in'two sections-an inner section I5a and an outer section I 5b. As shown in Figure 4, the inner section I 5a is mounted on a non-circular portion 66 of the shaft I4, and the outer section I3b is interlocked with the inner section by a non-circular projection 81 on the inner section and al pockets and 46 in the cam sleeve 42, thus f permitting the shaft to assume its left-hand position as viewed in Figure 4, under the influence of the spring 39. The clutch teeth 31 and 38 are thus interengaged to effect a driving connection between the shaft I4 and the worm I3, whereby rotation of the shaft effects rotation of the' worm and the worm wheel l2 to tilt the slats.

If, as the result of slippage between the cord i8 and the pulley I5, the ends of the cord become unequal to a pronounced degree, this condition 'Y may be corrected by grasping both lengths of cordV and swinging them in an arc about the axis of the shaft I 4, in a plane parallel to the plane of the blind. This manipulation of the cord causes the guard member to rotate about the shaft r:

into a position such as that shown in Figure 5, and the interlocking connection between the llugs von the guard member and the pockets 45 and 46 in the cam sleeve 42 constrains the cam sleeve to rotate with the guard member. sleeve is rotated, engagement of the cam surfaces 48 on the cam sleeve with the stationary lugs 5I and 52 forces the cam sleeve and hence the shaft I4 to the right, as viewed in Figure 4, thus disengaging the clutch teeth 31 and 38. While eX- erting slight tension on both lengths of the cord to maintain the guard member 55 in its inclined position, the cord lengths may be equalized by pulling on the shorter length and slacking off on the longer length, the pulley and the shaft being free to rotate relative to the worm I3.

During the cord adjusting operation just described, the compression spring 39 exerts axial As the cam tion of the shaft will bring them into alignment.' It will be apparent that inasmuch as the camsleeve 42 is provided with the oppositely inclined'- cam surfaces 41 and 48, rotation of the guard member-'55 in either direction will effect axial`-` movement of the shaft to disengage the clutch. This constitutes a distinct advantage since in some instances it may be inconvenient or even impossible to swing the cords only in the direction illustrated herein.

The tilting mechanism described herein, being of exceedingly simple and yet rugged construction, may be manufacturedat low cost. Sub'- stantially all parts thereof are, in fact, so designed as to be readily produced either by diecasting or molding processes, a factor which further contributes to economy of manufacture. By

reducing the number of parts and by avoiding intricacy of design, not only is the cost reduced but also a more rugged and durable product'is obtained.

Although there has been described only a single, preferred embodiment of the invention,

it wil-l be apparent that the construction may" be modified in various respects without departing. from the scope of the invention as defined by the appended claims.

I claim:

l. A tilting mechanism for a Venetian blind comprising a frame, a shaft journaled .in said frame, a pulley fixed to one end of said shaft, tilting means on said frame adapted to be oper-- ated by rotation of said shaft, clutch :means at the other end of said .shaft operably connecting said shaft and said tilting means, said clutch.y

means being disengaged upon axial :.novement of said shaft relative tosaid frame, and means for effecting said axial movement including a cam rotatable on said shaft and a cam follower with respect'to said frame.

2'. A tilting mechanism for a Venetian blind comprising a frame, a shaft journaled in said frame, a pulley fixed to one end of said'shaft,

tilting means adapted to be operated by rotation of said shaft, clutch means at the other end of said `shaft operably connecting said shaft and relative to said frame to disengage said clutch means, and a cord guard rotatable on said shaft and operably connected to said cam member,

force on the shaft I4 tending to return it to its normal operating position, but inasmuch as the lugs 52 are at that time in engagement with the short circumferentially extending surfaces 59 at the extremities of the cam surfaces 48, the axial force exerted by the spring 39 does not tend to rotate the cam sleeve and the guard member back to their normal operating positions. Since it is therefore unnecessary for the operator to continuously oppose any tendency by the guard member to return to itsY normal position during equalizing of the cord lengths, this operation is facilitated and the mechanism is relieved of undue strain to which it would otherwise be subjected.

Upon completion of the cord-equalizing adjustment, the operator returns the cords to their normal vertical positions to rotate the guard member to its normal position, whereupon the spring 39 forces the shaft outwardly to re-engage the clutch teeth 31 and 38. In the event the teeth are not aligned for engagement, a slight rotawhereby upon rotation of said guard said shaft is disconnected from said tilting means.

3. A tilting mechanism for a Venetian blind comprising a frame, a shaft .lournaled in said frame for rotary and axial movement, blind tilting means adapted to be operated by rotationof said shaft, cooperating clutch elements on said.

shaft and said tilting means, comprising longitudinally extending interengaging projections and recesses and4 adapted to be disengaged by axial movement of said shaft relative to said frame, a cam member rotatable about an axis and axially and inwardly movable relative to said frame vbut fixed against axial movement relative to said shaft, said cam member having a cam surface, a stationary camv follower fixed to said frame and engagable with said cam surface for moving said cam member axially upony rotation thereof, and means for rotating said cam member.

4. A tilting mechanism for Venetian blinds comprising a shaft, a pulley on one end of said shaft, blind tilting means adapted to be operated by rotation of said pulley, clutch means operably connecting said pulley with said tilting means at theother endof said shaft, cam means rotatable on said shaft, and operable on rotation thereof in either of opposite directions for disengaging said clutch means, and means for rotating said cam means in either direction.

5. A tilting mechanism for Venetian blinds comprising a shaft, mounting means for said shaft, a pulley on said shaft, blind tilting means adapted to be operated by rotation of said pulley, clutch means operably connecting said pulley with said tilting means, a cam member rotatable on said shaft and having oppositely inclined cam surfaces, astationary cam follower fixed on said mountingnieans, engagable selectively with each of said camsurfaces upon rotation of said cam member in opposite directions and operable upon engagement with eitherlof said cam surfaces to actuate said cam member to release said clutch means, and means for rotating said cam member in either direction and moving said cam member axially inwardly toward said tilting means.

6. A tilting mechanism for a Venetian blind comprising a frame, a shaft journaled in said frame and mounted for axial movement relative thereto, a worm journaled on said shaft, a worm wheel meshing with said worm and adapted for connection with a blind, cooperating clutch elements on said shaft and worm, comprising longitudinally extending interengaging projections and recesses and adapted to be disengaged upon axial movement of said shaft, and cam means journaled in said frame coaxially with said shaft for inward movement therewith toward and relative to said worm and operable upon rotation thereof to move said shaft axially to disengage said clutch elements.

7. A tilting mechanism for a Venetian blind comprising a frame, a shaft journaled in said frame and mounted for axial movement relative thereto, a worm journaled on said shaft, a worm Wheel meshing with said worm and adapted for connection with a blind, cooperating clutch elements on said shaft and worm, comprising longitudinally extending interengaging projections and recesses and disengageable upon said movement of said shaft, a pulley fixed to said shaft and adapted to receive an operating cord, a cord guard carried by said shaft and engagable with said cord, said guard being rotatable on said shaft and movable inwardly with said shaft relative to said worm, and cam means associated with said guard for inward movement therewith and operable upon rotation of said guard about the axis of said shaft to disengage said clutch elements.

8. A tilting mechanism for a Venetian blind comprising a frame, bearing recesses at opposite ends of said frame, a shaft having an end portion journaled in one of said bearing recesses, a sleeve member journaled in the other recess for inward axial movement relative to said frame, said shaft extending through said sleeve and being journaled therein, said sleeve having a cam surface on the periphery thereof, and a projection on said frame in said other bearing recess and engagable with said cam surface for effecting said movement of the sleeve member on rotation thereof.

9. A tilting mechanism for a Venetian blind comprising a shaft, blind tilting means adapted to be operated by rotation of said shaft, clutch means operably connecting said shaft and said tilting means, a rotatable cam sleeve journaled on said shaft for inward movement axially of the shaft and operable to disengage said clutch means, a cam recess on said sleeve, a pulley on said shaft and adapted to receive an operating cord, and a cord guard rotatable on said shaft and movable inwardly towardsaid tilting means, said cord guard having a projection thereon received in said cam recess to eifect rotation and inward movement of said sleeve upon rotation of said cord guard.

10. In a tilting device for Venetian blinds, a shaft, mounting means for said shaft, a pulley fixed to one end of said shaft adapted to be rotated by means of an operating cord, tilting means operable responsive to rotation of said pulley, clutch means at the other end of said shaft including clutch elements carried by said tilting means and said shaft respectively, means urging said elements into clutching engagement, a oord engaging member movable relative to said mounting means, and cam means operable responsive to movement of said cord engaging member for disengaging said clutch elements.

11. A tilting device for Venetian blinds, comprising; a shaft, mounting means for said shaft, a pulleyY fixed to said shaft and adapted to be rotated by an operating cord, tilting means mounted for operation responsive to rotation of the shaft, clutch means disposed between one end of the shaft and said tilting means including cooperable clutch elements on said tilting means and said shaft respectively, cam means between the other end of the shaft and said tilting means including a member shiftable axially for disengaging said clutch elements, and a cord engaging member for operating said cam means.

12. In a tilting device for a Venetian blind, a shaft, mounting means for said shaft, a pulley fixed to said shaft for rotation by means of an opl erating cord, tilting means, clutch elements on the shaft and the tilting means respectively, means urging said clutch elements into clutching engagement, a cord guide mounted on the shaft for rotative and inward axial movement relative to said mounting means responsive to manipulation of said cord, cam means for declutching said clutch elements including a cam member having a cam surface thereon and being operatively connected to said cord guide and mounted on said shaft for rotative and axial movement relative to said mounting means, and a stationary cam follower xed on said mounting means and engaging said cam surface.

JAMES C. BENNETT.

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

VUNITED STATES PATENTS

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