[0001] The invention relates to a chain stopper for a ball chain, particularly for an operating
system of a window blind, such as a horizontal or vertical venetian blind, a roller
blind or the like.
[0002] Ball chain operating systems for window blinds are known in the art, for example,
in DE 87 00 548, DE 297 11893. They generally include a sprocket or drive wheel for
driving a driven blind member such as a drive shaft, a ball chain operatively engaging
the sprocket wheel, a cover on the sprocket wheel and a chain stopper on the ball
chain. In these systems, the sprocket wheel is drivingly connected to a driven member
of a blind; in DE 87 00 548, the blind is a roller blind, and in DE 297 11 893, the
blind is a vertical venetian blind. A sprocket wheel can also drive other blinds,
such as a horizontal venetian blind or a roman shade. The driven member can be a conventional
drive shaft of a roller blind, a central control shaft of a roman shade, a lift or
tilt shaft of a horizontal venetian blind or a traverse or tilt shaft of a vertical
venetian blind, or the like.
[0003] The ball chain, in such systems, comprises a plurality of spaced apart balls. The
ball chain is looped over the sprocket wheel to operatively engage it, so that first
and second depending portions of the ball chain are on either side of the sprocket
wheel. By pulling one of the depending portions of the ball chain, the sprocket wheel
is rotated in either a clockwise or counter-clockwise direction, and the driven shaft
also is rotated. This results in a roller blind being rolled up or unrolled, a venetian
blind being tilted or lifted or lowered, a vertical venetian blind being traversed
or tilted or a roman shade being lifted or lowered.
[0004] The sprocket wheel, in such systems, is provided with a cover. The cover generally
is over at least the part of the sprocket wheel where the ball chain is looped over
it, but open top covers are also known (e.g., US 2,577,046). The cover is open at
the bottom for passage of the opposite depending portions of the ball chain. The cover
acts as a guiding means to guide the ball chain into engagement with the sprocket
wheel and prevent the ball chain from disengaging from the sprocket wheel.
[0005] In such systems, ball chains have been provided with one or more separate members
which act as chain stoppers. The stoppers have been adapted to block movement of the
ball chains, thus stopping the rotation of the sprocket wheels and operating movement
of the blinds. They have also been used to prevent ball chain from being pulled further
than necessary for performing desired operating movements of the blinds, for example,
for preventing further than a maximum tilt of a venetian blind or preventing a roller
blind from being rolled-up too far whereby its bottom bar would bang against its roller
or its housing.
[0006] The stoppers of DE 87 00 548, DE 297 11 893 grip two adjacent balls of their ball
chains and have a cross-section that is bigger than the cross-section of the balls.
These stoppers thus block the ball chains at the bottom of their covers and prevent
the ball chains from being further pulled over their sprocket wheels. Such stoppers
also connect the separate ends of the ball chains by gripping over and connecting
together the last ball of each ball chain end.
[0007] A drawback of these stoppers is that they are very visible and rather ugly. Also,
their size prevents them from sliding through cord weights, such as are generally
used on vertical blinds. Such a cord weight is described, for example, in US 6,325,132,
and comprises a pulley rotatably mounted within a weighted outer shell.
[0008] In accordance with this invention, a chain stopper is provided for attachment to
a ball chain having a plurality of balls which are spaced apart along the length of
the chain and are interconnected by a plurality of intermediate chain members that
extend along the length of the chain between adjacent balls; the stopper being adapted
to be attached to the chain between two adjacent balls, about an intermediate chain
member between the two adjacent balls, and being characterized by a maximum cross-sectional
size that is equal to or less than the size of the maximum cross-section of the balls
of the chain. This stopper is less visible and can slide through a cord weight along
with the ball chain, to which it is attached.
[0009] Advantageously, the stopper has a length, along the length of the chain, that is
equal to or less than the distance between the maximum cross-sections of any two adjacent
balls along the length of the chain. Also advantageously, the stopper has a top and
a bottom, an outer surface and a hollow interior extending between the top and bottom.
It is especially advantageous that the stopper is generally cylindrical. It is also
especially advantageous that the hollow interior of the stopper has a general hour-glass
shape, with a top bowl-like socket, a bottom bowl-like socket and a bore or passage
connecting the two sockets. It is also especially advantageous that the stopper has
a slot that extends between its top and bottom and extends from its outer surface
to its hollow interior. Also advantageously, the stopper comprises two parts.
[0010] Also in accordance with this invention, a ball chain is provided having a plurality
of balls which are spaced apart along the length of the chain and are interconnected
by a plurality of intermediate chain members that extend along the length of the chain
between adjacent balls; and the chain being characterized by a chain stopper of this
invention, attached to the chain about an intermediate chain member between two adjacent
balls.
[0011] Further in accordance with this invention, a blind operating system is provided comprising:
a sprocket wheel for driving a driven blind member; a ball chain looped over the sprocket
wheel and operatively engaging it; and a cover over at least a portion of the sprocket
wheel that is in contact with the ball chain; the chain having a plurality of balls
which are spaced apart along the length of the chain and are interconnected by a plurality
of intermediate chain members that extend along the length of the chain between adjacent
balls; and the system being characterized by at least one chain stopper of this invention,
attached to the chain about an intermediate chain member between two adjacent balls.
[0012] Further aspects of the invention will be apparent from the detailed description and
drawings, in which:
- Figure 1 is a perspective view of a first embodiment of a chain stopper of the invention
on a portion of a ball chain;
- Figure 2 is a perspective view of the stopper of Figure 1;
- Figure 3 is a perspective view of an operating system for a roller blind, including
a sprocket wheel, a ball chain, and the stopper of Figures 1 and 2, cooperating with
the sprocket wheel in a socalled 'stop-position';
- Figure 4 is a detail view of Figure 3, showing the stopper of Figures 1-3 cooperating
with the sprocket wheel in the 'stop-position';
- Figure 5A is a perspective view of a second embodiment of the stopper of the invention
on a ball chain;
- Figure 5B is a perspective view of the stopper of Figure 5A;
- Figures 6A-6C are perspective views of third, fourth and fifth embodiments of the
stopper of the invention on ball chains; and
- Figure 7 is a perspective view of the two-part stopper of Figure 6A.
[0013] Figure 1 shows a portion of the length of a conventional ball chain 1 with a plurality
of balls 3 that are spaced apart along the length of the chain 1. Connecting each
pair of adjacent balls 3 and extending between them, along the length of the chain
1, is an intermediate chain member 5. Preferably, the intermediate chain members 5
are all of equal length along the length of the chain 1. The distance between two
adjacent balls 3 along the length of the chain 1 is a function of the length of the
intermediate chain member 5 between them.
[0014] Each ball 3 is preferably spherical as shown in Figures 1-6 but can have another
shapes as described below. The maximum cross-section of each ball 3, perpendicular
to the length of the ball chain 1, is indicated as "MC
ball" in the Figures. The location of this maximum cross-section MC
ball on a spherical ball 3 coincides with the meridian 3A of the ball. For other non-
spherical balls 3, their maximum cross-section MC
ball will be described in relation to their meridians as explained below.
[0015] As shown in Figure 1, a first embodiment of a chain stopper 7 of this invention is
provided on the ball chain 1, between a pair of adjacent balls 3, 3' and about the
intermediate chain member 5, between them. The stopper 7 has a length, parallel to
the length of the chain 1, that is indicated as "L
stopper" and is preferably equal to or less than the distance, along the length of the chain
1, between the maximum cross-section MC
ball at the meridians 3A, 3A' of its adjacent balls 3, 3'. The maximum cross-section of
the stopper 7, perpendicular to the length of the chain 1, is indicated as "MC
stopper" in the Figures. Preferably, MC
stopper of the stopper 7 is equal to or less than MC
ball of the balls 3 of the chain 1.
[0016] Figure 2 shows the stopper 7 as comprising a generally hollow cylindrical body 9
with a top 11, a bottom 13, an inner surface 15, an outer surface 17 and a slot 19
that extends lengthwise between the stopper's top and bottom 11, 13 and also extends
from the stopper's outer surface 17 to its inner surface 15 and its hollow interior
21. The hollow interior 21 is of an hour-glass like shape having a upper bowl-like
socket portion 23 at the top 11 of the stopper, a lower bowl-like socket portion 25
at the bottom 13 of the stopper and a connecting passage or bore 27 between the two
socket portions 23, 25. The top bowl-like socket portion 23 is suitably shaped to
accommodate a portion of the upper adjacent ball 3 in a ball-socket jointed type connection,
and likewise, the bottom bowl-like socket portion 25 is suitably shaped to accommodate
a portion of the lower adjacent ball 3'. The bore 27 within the stopper's hollow interior
21 extends parallel to the length of the chain and can accommodate the intermediate
chain member 5 between the adjacent balls 3, 3' when the stopper is attached to the
chain 1.
[0017] Because the slot 19 of the stopper 7 connects its outer surface 17 with its hollow
interior 21, the slot 19 allows the stopper to be removably assembled to the ball
chain 1 between any pair of adjacent balls 3, 3'. The slot 19 can be slid over an
intermediate chain member 5, so that the stopper 7 surrounds the intermediate chain
member which then lies in its hollow interior 21. The slot 19 also allows for slight
movement of the adjacent balls 3,3' relative to the sockets 23, 25.
[0018] As shown in Figure 2, the slot 19 of the stopper 7 preferably has a wedge shape --
larger at the opening 18 in the stopper's outer surface 17 and much narrower at its
inner surface 15 about its hollow interior 21. This shape facilitates the attachment
of the stopper 7 to the chain 1. Also instead of simple straight edges in the stopper's
outer surface 17, about the opening 18 in the lengthwise slot 19, such edges 29 preferably
form an hour-glass like contour in the stopper's outer surface 17, about the slot
19. The hour-glass contour of slot 19 has a top width 19A, an intermediate width 19B
and a bottom width 19C. The top width 19A is sufficient for passage of the upper adjacent
ball 3 onto the upper socket 23 of the stopper body, and the bottom width 19C is likewise
sufficient for passage of the lower adjacent ball 3' onto the lower socket 25 of the
stopper body. The intermediate width 19B is for passage of the intermediate chain
member 5 into the bore 27 of the stopper's hollow interior 21.
[0019] Figure 3 shows an operating system 30 for a roller blind (not shown) with the ball
chain 1 and the stopper 7 of Figures 1 and 2. The system 30 is shown from a front
side, on which the system will be attached to the blind's drive shaft (also not shown).
[0020] As shown in Figure 3, the operating system 30 has a conventional drive or sprocket
wheel 40 that is at least partially covered by a conventional cover or housing 60.
The chain 1 is looped over, and thereby operatively connected to, the sprocket wheel
40. A left or first depending chain portion 1A and a right or second depending chain
portion 1 B of the chain 1 are on opposite sides of the sprocket wheel 40. A portion
of an optional cord weight or tensioner 80 is shown, suspended from the chain portions
1A, 1B.
[0021] As also shown in Figure 3, the sprocket wheel 40 has a front web 41 and a rear web
43 (not shown) and an circumferential outer surface 45 between the front and rear
webs. On the outer circumferential surface of the sprocket wheel 40, the front and
rear webs 41, 43 each have a plurality of radially-extending sprocket teeth 47 that
alternate with pockets 49 suitable for accommodating the balls 3 of the chain 1.
[0022] As further shown in Figures 3 and 4, at the rear of the cover 60 is a base 61, rotatably
connected to, and supporting, the rear side of the sprocket wheel (not visible). A
flange 63 extends axially and frontwardly from the base 61. The flange 63 is dimensioned
and shaped to cover at least a radial portion of the circumferential surface of the
sprocket wheel 40. A gap 65 between an inner surface 67 of the flange 63 and the outer
surface 45 of the sprocket wheel 40 is sufficiently wide to allow the sprocket wheel,
with the ball chain 1 looped over it, to rotate within the cover 60 but is sufficiently
narrow to prevent the chain 1 from disengaging from the sprocket wheel. The flange
63 does not cover the lower radial portion of the outer surface 45 of the sprocket
wheel 40, thus allowing the balls 3 to sequentially engage separate pockets 49 of
the sprocket wheel as one of the depending chain portions 1A, 1 B is pulled and the
sprocket wheel is rotated. The cover 60, at the lower radial portion of the outer
surface 45 of the sprocket wheel, also includes a lower left flange portion 69 and
a lower right flange portion 71, and between them extends an open portion or flange
free portion 73 of the base 61. The open portion 73 can be a unitary or single portion
wide enough for both depending chain portions 1A, 1 B, or it can include an intermediate
flange portion (not shown), creating separate, left and right channels, one for each
depending chain portion.
[0023] The base 61 of the cover 60 also preferably includes means (not shown) for attaching
the cover to a conventional mounting bracket for the blind that is to be attached
to the system 30.
[0024] As still further shown in Figure 3, the cord weight 80 includes a rotatable pulley
81 and a weighted or tensioned shell 83. The stopper 7 can pass through the pulley
81 unhindered, because the pulley is not a sprocket wheel. Preferably, the ball-socket
connection 23, 25 between the stopper 7 and the adjacent balls 3, 3' adds flexibility
to the ball chain 1, allowing the stopper to pass even more easily with the chain
through the cord weight 80 and around its pulley 81.
[0025] In use, pulling one of the depending portions 1A, 1B of the ball chain 1, looped about the
sprocket wheel 40, causes the sprocket wheel to move with the chain and to rotate
counter-clockwise or clockwise as shown in Figure 3. The roller of the blind (not
shown) will rotate together with the sprocket wheel, and the blind will be rolled
about the roller or unrolled from the roller, depending upon its direction of rotation.
[0026] The chain stopper 7 is shown in Figures 3 and 4 in a left stop position P. In this
stop position, even if the left depending chain portion 1A is pulled downwardly, the
sprocket wheel 40 will not rotate. From this position, the sprocket wheel can only
be rotated in an opposite direction by pulling downwardly the right depending chain
portion 1B. In the left stop position P, the stopper 7 is caught between a tooth 47
of the sprocket wheel 40 and an inner surface 67 of the lower right flange portion
71 of the cover 60.
[0027] Figures 5 to 7 show alternative embodiments 107, 207, 307 and 407 of the chain stopper
of the invention which are similar to the stopper 7 of Figures 1-4 and for which corresponding
reference numerals (greater by 100, 200, 300 and 400, respectively) are used below
for describing the same parts or corresponding parts.
[0028] Figure 5A shows a second embodiment 107 of the chain stopper assembled to a ball
chain 101.
[0029] Figure 5B shows that the stopper 107 has a hollow cylindrical body 109 with a top
111, a bottom 113, an inner surface 115, an outer surface 117 and a slot 119 that
extends lengthwise between its top 111 and bottom 113 and which also extends from
its outer surface 117 to its inner surface 115 and its hollow interior 121. The hollow
interior 121 has a general cylindrical bore 127 for accommodating an intermediate
portion 105 of the ball chain 101, between two of its adjacent balls 103, 103'.
[0030] The stopper 107 has a slot 119 which allows the stopper 107 to be removably assembled
to the chain 101 between any pair of adjacent balls 103, 103' and about intermediate
chain member 105. The slot 119 is preferably shaped like a wedge that is wider at
the outer surface of 117 of the stopper than at its inner surface 115, about its hollow
interior 121, so as to allow for easy attachment of the stopper to the chain. The
length of the stopper between its top 111 and bottom 113 is equal or less then the
length of the intermediate chain member 105 between two adjacent balls 103, 103'.
[0031] Figure 6A shows a third embodiment 207 of the chain stopper having a hollow cylindrical
body 209 with a top 211, a bottom 213, an inner surface 215, an outer surface 217
and a hollow interior 221. The two-part stopper 207 has a left body half 209A and
a right body half 209B, enclosing an intermediate portion 205 between two adjacent
balls 203, 203' of a ball chain 201. The body halves 209A, 209B can have a flexible
joint between them at one side, shaping the stopper into a book-like member. No slot
extending lengthwise between the stopper's top and bottom 211, 213 and from its outer
surface 217 to its inner surface 215 is necessary. The two halves 209A, 209B of the
stopper 207 can be closed about the intermediate chain member 205 in any conventional
manner, for example with an adhesive. The stopper halves 209A, 209B can also be made
so that they can be reopened as described below with regard to Figure 7.
[0032] Figure 6B shows a fourth embodiment 307 of the chain stopper, having a hollow cylindrical
body 309 with a top 311, a bottom 313, an inner surface 315, an outer surface 317
and a hollow interior 321. The stopper 307 has top and bottom sockets 323, 325 which
are very shallow, Thereby, the lengthwise slot (not shown), between the stopper's
top and bottom 311, 313 and from its outer surface 317 to its inner surface 315, can
have the shape of the slot 119 of the stopper 107 of Figures 5A and 5B.
[0033] Figure 6C shows a fifth embodiment 407 of the chain stopper, having a hollow cylindrical
body 409 with a top 411, a bottom 413, an inner surface 415, an outer surface 417
and a hollow interior 421. The stopper 407 is shaped like a ball. Indeed, the stopper
407 could be an additional ball between two adjacent balls 403, 403' of the ball chain
401, provided the intermediate chain member 405 is long enough to accommodate such
an extra ball.
[0034] Figure 7 shows details of the two-part stopper 207 of Figure 6A. The left and right
body halves 209A, 209B have a snap-locking mechanism 275 for releasable opening of
the stopper. The snap-lock mechanism includes a left snap-lug 277A (not shown) on
the left body half 209A, and a complementary right snap-lug retainer 279B on the right
body half 209B. Similarly, there is a right snap-lug 277B on the right body half 209B,
and a complementary left snap-lug retainer 279A on the left body half 209A. When the
two body halves are placed about an intermediate chain member 205, the halves can
be snapped shut and are then in operative engagement. The ball chain 201 and stopper
207 are ready for use.
[0035] To release of the snap-lock mechanism 275, a tool (like a screw-driver or a pen)
can be inserted in the opening between the body halves 209A, 209B to push the snap-retainers
279A, 279B and the snap-lugs 277A, 277B out of operative engagement.
[0036] This invention is, of course, not limited to the above-described embodiments which
may be modified without departing from the scope of the invention or sacrificing all
of its advantages. In this regard, the terms in the foregoing description and the
following claims, such as "left", "right", "clockwise", "counter-clockwise", "front"
and "rear", have been used only as relative terms to describe the relationships of
the various elements of the chain stopper of the invention for a ball chain for an
operating system of a window blind. For example, the chain stoppers 7, 107, 207, 307
and 407 could be used for venetian blinds or pleated blinds, not just roller blinds.
[0037] Likewise, the ball chains 1, 101, etc. could be shaped by balls formed on a chain
or cord, in which case the intermediate chain members 5, 105, etc. would be portions
of the chain or cord material. Altematively the ball chains could be shaped by balls
and the intermediate chain members that are assembled to form the ball chain. Preferably,
the ball chains includes a cord and plastic balls that are formed on the cord, but
the balls could also be crimped on a braided cord or the ball chains could be integrally
formed by injection molding.
[0038] Similarly, non-spherical balls, such as balls of oblong cross-sections, could be
used, I ball chains of this invention. For example, conical, tetrahedonical or cylindrical
balls as shown in WO 03/033853 (Figures 5-8) could be used. However, the size and
spacing of such balls in ball chains will have to be appropriate for the type and
size of the sprocket wheels, with which such ball chains are to be used.
[0039] For any non-spherical ball that has, along its length, a constant maximum cross-section
MC
ball, it can be assumed that its meridian is at the middle of its length. This can be
the case for balls of oblong, rectangular or square cross-sections. Any non-spherical
ball that has its maximum cross-section MC
ball at a certain point along its length, that point can be assumed to be the meridian.
This can be the case for conical, pyramidical or tetrahedonical shaped balls. Such
uncommon non-spherical balls can be made into ball chains of this invention and suitable
sprocket wheels can be made to co-operate with such ball chains. The chain stopper
of the invention will be suitable for ball chains comprising such non-round ball members.
[0040] As described above, the chain stoppers 7, 107, etc. have cross-sections that are
no bigger than the cross-sections of the balls 3, 103, etc. of the ball chains 1,
101, etc., with which the stoppers are to be used. However, so that the stoppers 7,
107, etc. function correctly, their cross-section (MC
stopper) also has to be at least somewhat bigger than the distance between the teeth 47 of
the sprocket wheel 40 and the inner surface 67of a lower flange portion 71 of the
cover 60. This distance is usually designed to let the intermediate chain members
5, 105, etc. closely pass without problem, but it can be larger. This means that depending
on the type of sprocket wheel 40 that is used, the thinnest possible chain stopper
7, 107, etc. can have a cross-section that is just slightly thicker than the cross-section
of the intermediate chain members 5, 105, etc. of the ball chains 1, 101, etc.
1. A chain stopper (7,107,207,307,407) for attachment to a ball chain (1, 101, 201, 301,
401), having a plurality of balls (3, 103, 203, 303, 403) which are spaced apart along
the length of the chain and are interconnected by a plurality of intermediate chain
members (5,105,205,305,405) that extend along the length of the chain between adjacent
balls; the stopper being adapted to be attached to the chain between two adjacent
balls, about an intermediate chain member between the two adjacent balls, and being
characterized by a maximum cross-sectional size (MCstopper) that is equal to or less than the size of the maximum cross-section of the balls
(MCball) of the chain.
2. The chain stopper of claim 1 which has a length (Lstopper), along the length of the chain, that is equal to or less than the distance between
the maximum cross-sections (MCball) of any two adjacent balls along the length of the chain.
3. The chain stopper of claim 1 or 2 which has a top (11, 111, 211, 311, 411), a bottom
(13, 113, 213, 313, 413), an outer surface (17, 117, 217, 317, 417), and a hollow
interior (21, 121, 221, 321, 421), extending between the top and bottom.
4. The chain stopper of claim 3 which is generally cylindrical.
5. The chain stopper (7, 307) of claim 3 or 4 wherein the hollow interior (21, 321) has
a generally hour-glass shape, with a top bowl-like socket (23, 323), a bottom bowl-like
socket (25, 325) and a bore (27,327) connecting the two sockets.
6. The chain stopper (107) of claim 3 or 4 wherein said hollow interior (121) is a cylindrical
bore
7. The chain stopper of any one of claims 1-6 which has a slot (19, 119, 219, 319, 419)
that extends between its top and bottom and extends from its outer surface to its
hollow interior.
8. The chain stopper of claim 7 wherein said slot (19, 119, 219, 319, 419) is wedge shaped
and is larger at the stopper's outer surface (17, 117, 217, 317, 417) and much narrower
at its hollow interior (21, 121, 221, 321, 421).
9. The chain stopper (207) of any one of claims 1-4 which comprises two parts (209A,
209B).
10. A ball chain (1, 101, 201, 301, 401) having a plurality of balls (3, 103, 203, 303,
403) which are spaced apart along the length of the chain and are interconnected by
a plurality of intermediate chain members (5,105,205,305,405) that extend along the
length of the chain between adjacent balls; the chain being characterized by a chain stopper (7,107,207,307,407) of any one of claims 1-9, attached to the chain
about an intermediate chain member between two adjacent balls.
11. A blind operating system comprising: a sprocket wheel (40) for driving a driven blind
member; a ball chain (1, 101, 201, 301, 401) looped over the sprocket wheel and operatively
engaging it; and a cover (60) that is over at least a portion of the sprocket wheel
and that is in contact with the ball chain; the chain having a plurality of balls
(3, 103, 203, 303, 403) which are spaced apart along the length of the chain and are
interconnected by a plurality of intermediate chain members (5,105,205,305,405) that
extend along the length of the chain between adjacent balls; and the system being
characterized by at least one chain stopper (7,107,207,307,407) of any one of claims 1-9, attached
to the chain about an intermediate chain member between two adjacent balls.