Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
"TILTER MECHANISM"
B~CKGROU~D OF THE INVENTION
The present invention relates to a tilter
mechanism for the slats of a venetian blind.
Many forms of such tilter mechanism have been
proposed before and these usually con~ist of a bracket
which is mountable in the venetian blind headrail, the
bracket carrying a housing in which are mounted a worm
which can be rotated from the exterior, and a wormwheel
which is operatively associated with the worm. A tilt
rod which passes through one or more tilt rolls
carryin~ the ladder means of the venetian blind is
engaged in the wormwheel. The tilt rod is usually of
non-circular, e.gO hexagonal or square cro3s-section,
- and this engages in a correspondingly shaped opening ln
the wormwheel. Known tilter mechanisms are relatively
bulky, complex and expensive to manufacture.
In many instances, it is desirable that the
venetian blind slats should only be rotatable by a
; ~ re~tricted amount to give a pleasing appearance to the
exterior of a building which has a large number of such-
venetian blinds therein. Certain proposals have been
made for restricting the rotation of the blind but none
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of these is particularly satisfactory and many of them are
rather expensive to manufacture.
It is now proposed, according to the present invention,
to provide a tilter mechanism for the slats of a venetian blind,
said mechanism comprising a housing, means for mounting said
housing on a venetian blind headrail, an externally operable
worm rotatably mounted on said housing, a wormwheel rotatably
mounted on said housing in operative engagement with said worm,
an axial extension at each axial end of said wormwheel, a recess
10 in each of said extensions adapted to receive the end of a tilt
rod such that the tilt rod can be inserted into either one of
the recesses in said extensions and thus extend either to the
left or to the right of said wormwheel, engaging means provided
on each of said extensions, each of said engaging means being
15 engageable either by a locking device to hold said tilt rod in
place or by a rotation control member mountable on the
corresponding extension.
Such a structure can be manufactured relatively
simply and the same tilter mechanism can be used whether or not
20 one is intending to have the mechanism at one end of the blind
or the other. In other words the tilt rod can extend either
from the left side or from the right side of the tilter
mechanism.
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It is also proposed to provide a rotation control
member including two abutmentR, said control member.
being mountable on the other of said ex~ensions and
for stop means to be provided on said bracket engage~ble
by said abutments on said rotation control member to
restrict rotation thereof., the engageable means on each
of said extensions being engageable either by a locking
device to hold said tilt rod in place or by said
rotation control member, to define a particular rotational
p~ition of said control member on said other extensionO
The rotation control member advantageously
comprises at least one disc which ha~ a central opening,
and at least one notch extending radially outwardly.
from the central opening,and two radially outwardly
extending abutment surfaces adjacent the outer periphery
of said at least one disc, these surfaces forming the
abutments mentioned above~ The engaging means formed
on the extension~ of the wormwheel can then comprise a
: radially outwardly extending key on each of the axial
extensions, the key being engageable in the notch or
. notches of the disc,
Preferably the disc has a plurality of notches
which are equiangularly spaced from one another on the
: disc, whereby the rotational position of the diw can be
cho~en to give a particular rotational movement
possibility for the tilt rodO
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The locking device which may be provided~ can
be a spring which can be snap-fitted over the keyO For
example, the locking device can be in the form of a spring
clip which i8 mounta~le on the tilt rod and haY an oriice
adjacent one end which is engageable over the keyO
- A particular advantageous arrangement is one in
which each key has an inclined ramp surface at.the end
remote from the wormwheel, the spring clip having an
upturned end portion for sliding up the ramp surface,
whereby the orifice can snap over the end of the key which
is nearer to the wormwheelO The spring clip may, for
example, comprise a V-~haped member which ha~ openings in
each arm of the V, whereby the tilt rod can be pa~sed through
the openings to mount the ~pring clip on the tilt rod,
.one arm of the V having, at its free end, a bent-down end
portion which includes the orifice.
It is also contemplated, according to the
present invention, to provide a rotation control member for
controlling the rotation of a venetian blind tilt rod, said
rotation control member comprising at least one disc having
a central opening, a plurality of equiangularly spaced
notches extending radially outwardly from said central
: opening, two radially outwardly extending abutment surfaces
adjacent th,e outer periphery of said at lea~t one di~c,
said member being mountable upon the wormwheel of a
venetian blind tilter with one of the notche~ engaging a
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key on the wormwheel and the abutment surfaces being
engageable with stops on the mountIng bracket of the
tilter to control rotation of the tilt rod.
In order that the invention may more readily
be understood, the following description i~ given, merely
by way of example, reference being made to the accompanying
drawings, in which:-
Figure 1 is a section through a venetian blindheadrail with one embodiment of tilter mechani.sm according
to the invention mounted therein,
Figure 2 is a front elevation of the tilter
mechanism of Figure 1,
Figure 3 is a view similar to Figure 1 showing
a second embodiment of tilter mechanism in the headrail,
Figure 4 is an end view of the tilter of
Figure 3 showing the rotation control member, and
Figure 5 i8 a perspective view of the spring
: clip locking device of the mechanisms of Figures 1 to 4,
Figure 6 is a view similar to Figure 4, showing
an alternative rotation control member, and
Figure 7 i9 an exploded perspective view of the
rotation control member of Figure 6.
The tilter mechanism illustrated in Figures 1
and 2 is shown as mounted in a headrail 10 having a front
wall ll, a rear wall 12 and a lower web 13, The front and
rear walls 11 and 12 have inturned rim~ 14 and 15
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respectively, as is conventional,
The tilter mechani~m is indicated by the
general reference numeral 16 and compri~es a bracket 17 on
which is mounted a housing 18, the bracket having lugs 19
which engage under the rim 15 while the housing 18 has a
portion 20 engaging under the rim 140
The front bottom portion 21 of the bracket prQjects
through an opening 22 formed in the headrailO
It wi l be noted that the lower wall 23 of the
bracket 17 is provided with two turned up stop lugs 24 and
25 which may be turned up for a reason to be explained later,
with reference to Figures 3 to 7O
Mounted for rotati.on within the housing 18 i~ a
worm 30 which may be driven by its ~haft 31 connected to
a conventional wand (not shown). A wormwheel 32 is
rotatable about an axi~ perpendicular to the axi~ of the
shaft 31 and is in operative engagement with the worm 30
so that rotation of the worm will cau~e rotation of the
wormwheel, in a conventional manner~
Extendlng axially from each end of the wormwheel
32 are extension~ 33 and 34 respectively, the~e being
provided with internal blind recesses 35 and 36 and are each
~ provided al~o with a radially outwardly extending key or
;~ projection 37,38~ It will be noted that each of the
projections 37,38 includes, at the end remote from the
wormwheel, an inclined ramp upper surface 39,400
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Engaged in the hexagonal blind recess 36,
is a hexagonal tilt rod 60 and this is held in place by
a spring clip 61 which is shown in greater detail i~.
Figure 50 The spring clip is of a generally V-~haped.
-construction having two arm~ 62 and 63 provided with
square cross-section holes 64 and 65~ The arm 63 has~
at its free end, a bent-down end portion ~6 which is
provided with a central orifice 670 Beyond the orifice
67 the bent-down portion is bent up again at 680
In order to mount the tilt rod, one first of
all grips the two arms 62 and 63 and squeezes them qo that
they move toward~ one another and the tilt rod 60 is
passed through the openings 64 and 65 and the spring is
then releasedO The arrangement is such that the spring
clip will clamp on to the tilt rod and-will be difficult
to move axially of the tilt rod~ The square cross-
section of the orifices 64 and 65 is such as to engage two
of the faces of the hexagonal tilt rod and two of the
angles thereofO
The tilt rod is then moved so that its end
engages in the recesq 36 and at this time the tip of
the turn-up portion 68 will ride up the ramp surface 40
and will flex the bent-down portion 66 upwardlyO Continued
movement to the left, as ~een in Figure 2, will enable the
orifice 67 to pass beyond the end of the ramp 40 so that
it will ~nap down over the end of the key 380 This will
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then prevent the tilt rod from being moved to the right
and will hold it in placeO It will be appreciated that
the tilt rod could equally be mounted to extend to the
left, then being engaged in recess 35 in extension 33O
Figures 3 and 4 show a modified construction,
like parts being indicated by like reference numeraLs,
The figures show the mounting of a rotation control member
50 which is a disc.ha~ing approximate~y the same axial
length as the stops 24, 25 which are turned up to form
stops 24a, 25aO The disc 50 is provided with a central
opening 51 and with eight equiangularly spaced radially
outwardly extending notches 52~ On its outer periphery,
the disc 50 has an outer circumferential portion 53 of
reduced radius, this portion terminating in two abutments
54 and 55. This portion in fact extends around a control
angle of, in this instance, approximately 180, Of
course, a different angle could be chosen if it were so
desired.
It can be seen from Figure 3 that the disc 50
is mounted on the extension 33 and that it is so mounted
that one of the notches 53 i9 engaged on the key 37.
In order to hold the disc in place, a grub screw 56 is
provided and thi~ i5 used to locate the disc at the same
axial position as the stop 24aO
In use, rotation of the shaft 31 by means of the
wand (not shown) will cause the worm to rotate and the
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wormwheel also to rotateO This in turn will cause
tilting of the tilt rod about its axis until the ab~tment
52 or 53, depending on the direction of rotation, abuts
the stop 24 whereupon further rotation will not be possibleO
It will be appreciated that if a different
angle is desired, then one simply selects a different one
of the notches 520
It will also be appreciated that this
construction also can be uced the other way~round, t~at is
with the tilt rod extending to the left rather than to the
right and with the rotation control disc on the right
rather than on the left~
The con~truction of the present invention is
relatively simple and inexpensive to manufacture and is of
universal use so that it can be operated either at one end
or the other and that the facility is provided for altering
the restriction of the rotation of the tilt rod, at will,
to suit any particular useO This alteration can be
achieved simply by selecting the particular one of the
notches 52 which one uses to locate on the key 37 or 38.
Of course, when the rotation control disc 50 is mounted on
the extension 34 engaging the key 38, the reduced section
portion 53 and the abutments 54 and 55 will cooperate with
the stop 25 rather than the stop 240
Figures6 and 7 show a different form of
: rotational control memberO A first disc 80 is provided with
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a central opening 81 and eight equiangularly spaced
radially extending notches 820 On its outer periphery
83 the disc 80 has a radial abutment projection 850
A second disc 90 with a central opening 91 has a similar
radial abutment projection 850 Two axially e~te~ding,
arrow-headed bifurcated pins 86 on the disc 90 can be
engaged in two of eight cooperating apertures 87 in disc
80, these being located between adjacent notches 820
Before assembly the discs are rotated relat-ive to one
another as indicated by the arrows to gi.ve the desired
circumferential spacingO In a modification the discs
80 and 90 are made identical to one another and each has,
for example, 7 apertures and one pinO This will redwce
production costsO The assembled discs can be mounted
in the same way as described aboveO
