Note: Descriptions are shown in the official language in which they were submitted.
CA 02020782 1999-09-08
DESCRIPTION
Support Device For A Picture Tube Component
TECHNICAL FIELD
The invention relates to a support device for a
picture tube component, especially for a deflection unit.
Generally, the deflection unit is clamped in position with the
aid of a clamping ring at the neck of the picture tube, and it
is supported on the tube cone with the aid of the support
device.
PRIOR ART
As soon as a deflection unit already firmly linked to
the neck of the picture tube is aligned so as to ensure that
imaging characteristics are satisfactorily provided within
specified tolerances, the unit must be fixed in the position
reached on the tube. In the current state-of-the-art, this is
achieved either by turning screws mounted in a retainer part
until they are flush against the tube cone, or by pushing wedges
between the above-mentioned retainer part and the tube cone. In
both methods of fastening, it has turned out to be difficult to
perform this fixing procedure so as to ensure that the set
position of the deflection unit is retained. It must be noted
that the deflection unit is firmly mounted inside the aligning
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unit, as is the picture tube. If now an operator tightens one
of the above-mentioned screws more than the others, then the
retainer part will move somewhat out of true, thus causing an
elastic force to build up, which relaxes when the tube with the
fixed deflection unit is removed from the aligning unit. There
is a similar effect when one of the fixing wedges is pressed
more firmly between cone and retainer part than the others.
Both when using screw-shaped support elements and
wedge-shaped support elements, it is accordingly not assured
that the aligned position of the deflection unit will be
retained when this is released from the aligning device.
The long-standing problem was accordingly to provide a
support device for a deflection unit for a picture tube
constructed so as to ensure that the deflection unit does not
alter its position when after being fixed on the picture tube
inside an aligning device it is removed from this device.
SUMMARY OF THE INVENTION
The support device described in this invention is
characterized by the fact that each support element can be moved
in the support direction inside a mounting, and that inside this
mounting it can be arrested in more than one setting position.
A support device of this kind is especially suited for adjusted
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retention of a deflection unit, but can also be used for
adjusted retention of a magnetic multipole unit, for example.
In order to illustrate the advantages of the
invention, let it be assumed that the support element is a pin,
which is guided in a mounting aligned on the picture tube, and
can be glued in the bore in any desired setting position. If,
after this desired alignment has been achieved, this pin is
moved so as to arrive flush against the picture tube, the
pressing force onto the pin does not affect in any way the
retainer part of the deflection unit, since the pin can be moved
freely in the bore in the retainer part. It is not until the pin
has been glued in the bore that it can transmit a force between
picture tube and deflection unit. If, however, the pin is
essentially inelastic, then even after gluing no misadjusting
force will be exerted.
The fact that a force between picture tube and
deflection unit can only be a force resulting from an elastic
deformation of the moved pin can be utilized in order to
selectively set a tension force between picture tube and
deflection unit. If, for example, the pin exhibits at its front
end contacting the picture tube a cap made of elastic material,
this latter will be deformed in dependence on the pressing force
of the pin onto the tube. This pressing force can be designed
to be relatively uniform, so that at all support points the same
tension force is exerted, thus ensuring that the alignment
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position achieved is retained unaltered. Such a relatively
precise adjustment of a prestressing force was not possible when
using conventional support elements. When conventional screws
were used, these would all have to be tightened with the same
torque, and it would have to be ensured that the torque is not
affected by friction, but is dependent only on the prestressing
force being achieved. This condition is in practice never
satisfied, since the parts used are made of plastic, meaning
that some screws are very easy to turn, and some very difficult.
The torque is thus substantially determined by friction, and for
this reason identical torques will not produce identical
prestressing forces. The situation is similar when conventional
wedges are used; with the aid of a relatively slight thrust
force, a wedge can enable a relatively high prestressing force
to be achieved. However, when identical thrust forces are
applied to different wedges, the result will be different
tension forces, since the thrust force is highly dependent on
the friction of the wedge between itself and the picture tube
and itself and the retainer part. It must also be noted that in
practice wedges with different angles are used, in order to
bridge different distances between deflection unit and picture
tube at different points. Even given identical friction forces
and identical thrust forces, there will be different tension
forces when wedges with different angles are used.
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On the other hand, as already explained, the tension
force when an elastic pin is used depends solely on the
pressing force used, provided that there is no very great
friction between pin and bore. The latter phenomenon can be
easily prevented, however, since it is not of the slightest
importance whether the pin fits snugly in the bore.
For quick attachment of a support element in the
mounting, it is of especial advantage when the support element
and the mounting possess catches which permit the support
element to move only towards the picture tube. Here the
component is fixed in position immediately the adjustment end
position is reached. However, between different fixing
positions there is a travel difference (depending on the lock
function), which may easily lead to slightly differing
tensions.
It is most especially advantageous when the support
element is const rutted in the form of a pin, which in a
longitudinal direction carries a thread over a part of its
circumference, and when the guide is constructed so as to
exhibit a recess of not less than the angular circumference of
the thread. As long as the support element is seated in the
guide so as to ensure that the partial thread is running in
the recess, it can be moved to and fro in the guide with a
very slight force. Once it has been moved into the desired
position, it merely needs to be turned a little, in order to
be fixed in position in relation to the guide. Depending on
the lead of the thread, the pin, when turned for fixing
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purposes, will be given a further forward movement in relation
to the guide, by a specified amount. In this way a precisely
defined tension can be set, depending solely on the lead of
the thread and the turning angle used.
In accordance with the present invention there is
provided support device for a picture tube component with more
than on support element, characterized in that each support
element comprises a pin that can be freely moved in the
support direction, inside a guide having a smooth inner
surface, and can be arrested in any position inside this
guide, said pin having a thread extending in a longitudinal
direction over a part of its circumference and said guide
having a recess of not less than the angular circumference of
the thread, whereby the thread may fit in the recess to allow
free longitudinal movement of the pin in the guide to any
desired arresting position where the pin can be locked by
rotation so that the thread engages the inner surface of the
guide.
In accordance with the present invention there is
further provided support device for a picture tube component
with more than one support element, each support element
comprising a pin that can be freely moved in the support
direction, inside a guide having a smooth inner surface, and
can be arrested in any position inside this guide, said pin
having a thread extending in a longitudinal direction over a
part of its circumference and said guide having a recess being
not less than the angular circumference of the thread so that
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the thread may fit in the recess to allow free longitudinal
movement of the pin in the guide to any desired arresting
position where the pin can be locked by rotation so that the
thread engages the inner surface of the guide characterized in
that each guide comprise an adhesive channel formed in the
smooth inner surface for introduction of adhesive for gluing a
pin in the guide.
In accordance with the present invention there is
further provided support device for a picture tube component
with more than one support element, characterized in that each
support element comprises a pin that can be freely moved in a
support direction, inside a guide having an inner surface, and
can be arrested in any position inside said guide, said pin
having grooves over at least a part of its circumference and
said guide having an adhesive channel formed in the inner
surface for the introduction of adhesive for gluing the pin in
the guide.
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SHORT DESCRIPTION OF THE DRAWINGS
Fig. 1 Side view of a deflection unit fixed in position of a
picture tube (only partially depicted);
Fig. 2 Plan view of the deflection unit in accordance with
Fig. 1;
Fig. 3 Side view of a pin-shaped support element with partial
thread;
Figs. 4A Cross-sections through a guide with a pin in
and 4B accordance with Fig. 3, once in the adjustment-
movement position (Fig. 4A) and once in fixing
position (Fig. 4B);
Fig. 5 Longitudinal section through a guide with a moving pin
with catches; and
Fig. 6 Longitudinal section through a guide with a pin which
can be glued inside the guide.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The deflection unit (10) in accordance with Figs. 1
and 2 comprises a retainer part with a front retaining ring (11)
and a rear clamping ring (12). The retainer part carries a
(diagrammatically depicted) deflection winding (13) and contacts
(14) .
At the circumference of the retaining ring (11),
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there are three support feet (15) under identical angular
distances. Each support foot (15) possesses a guide bore (16)
(Fig.4), with a pin (17) mounted inside it. Each pin (17) acts
as a support element for supporting the deflection unit (10) on
the cone (18.K) of the tube. At the tube neck (18.H), the
deflection unit is attached with the aid of the clamping ring
(12) .
The construction of the pins (17) and the associated
guide bores (16) can be seen in Figs. 3 and 4. Each pin (17)
possesses in a longitudinal direction two partial threads (19),
each of which extends over a part of the pin's circumference.
The tips of the threads exhibit a larger circumference than the
rest of the pin, which is constructed without a thread. This
can be seen especially clearly in Fig. 4A. The guide bore (16)
exhibits two recesses, which match the partial threads (19) are
constructed so as to ensure that the pin (17) can be moved
inside the guide bore (16) quite easily when it is inserted into
the bore in such a way that the partial threads (19) are aligned
with the recesses (21). In this position (4A), each pin
(17) can be moved to and fro at will in the associated guide
bore, and especially until contacting the tube cone (18.K). If
the pin (17) is turned by 90°, the partial thread (19) cuts into
the non-recessed parts of the wall of the guide bore (16). This
ensures that the pin (17) is fixed in position in the guide bore
(16), and simultaneously it is moved by a small distance,
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depending on the direction of turn, the angle of turn, and the
lead of the thread concerned.
In order to fix a deflection unit in position on a
picture tube, the following procedure is adopted, with the aid
of support elements constructed to the above design. First of
all, the deflection unit is pushed in the conventional manner
over the picture tube neck (18.H), and then attached in a
specified longitudinal position at the tube neck by tightening a
clamping screw (22) at the clamping ring (12). Then the tube
and the deflection unit (10) are contacted, and in operation of
these components the deflection unit (10) is adjusted with the
aid of an adjuster device until imaging characteristics are
within specified tolerances. In the aligned position, the
deflection unit (10) now has to be permanently fixed. It is
here that the pins (17) described above come into use; in the
position shown in Fig. 4A, they are pushed against the tube cone
(18.K). For forces operating between deflection unit (10) and
tube cone (18.K), it is immaterial how strong the pressing
forces on the pins (17) are, or in particular whether the forces
are identical at all pins or not. When a particular pin (17) is
moved against the tube cone (18.K), it is then turned by 90° into
the position shown in Fig. 4B, with the turn being performed in
the direction causing a further forward movement onto the tube
cone relative to the deflection unit (10). This turning
movement fixes the pins (17) in position, simultaneously causing
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the adjusted position of the deflection unit (10) being fixed as
well. Due to the small forward movement of the pins during
fixing, a small tension is achieved between deflection unit (10)
and tube, resulting in an especially secure seat of the
deflection unit (10). The adjusted position is not altered
thereby. The extent of the tension, given a fixed turn of 90° in
all cases, depends only on the lead of the thread, meaning that
it can be specified by this latter.
The pins (17) shown in Figs. 1 - 3 carry a widened
head with a slit (24) for turning purposes. However, it is not
necessary for there to be a widened head, and instead of a slit,
for example, an outer or inner multi-cornered configuration can
be provided. In addition, the pin can be modified so that
instead of two partial threads (19) more or fewer partial
threads are provided. If only one partial thread is provided,
the advantage is that when fixing in position, for example, the
pin can be turned by 270°, in order to achieve an especially
great fixing tension, if this should be necessary.
The pin (17.5) and the guide bore (16.5) in accordance
with Fig. 5 carry catches (25.17 and 25.16 respectively), which
are aligned so as to ensure that they permit the pin (17) to
move towards the picture tube cone (18.K). At its front end,
the pin (17.5) is fitted with a rubber cap. When the deflection
unit is being fixed in position, the pin is pressed against the
tube cone with a specified force, thus compressing the rubber
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cap (26) somewhat. The longitudinal-movement position of the
pin (17.5) in the guide bore (16.5) is determined by the locking
function achieved in each case. When the deflection unit is
released by the aligning device, the elastic deforming force of
the rubber cap (26) ensures that the deflection unit is braced
with a specified force against the tube.
In the embodiment shown in Fig. 6, a pin (17.6) with
grooves (27) is provided. The associated guide bore (16.6)
possesses an adhesive channel (28) for gluing the grooved pin
(17.6) when this latter has been pushed as far as the picture
tube cone. The grooved pin (17.6) is also at its front end
fitted with a rubber cap (26) for the purpose explained above.
The embodiments relate to designs of guide bores and
pins which are matched to each other so as to ensure that the
pins can be moved inside the guide bore without exerting great
force, but can be fixed in more than one adjustment positions,
preferably in any desired adjustment position, in relation to
the guide. Combinations of guides and pins with these
characteristics can be produced in many further embodiment
forms, e.g. also in dowel-like embodiment forms, i.e. with
configurations in which a wedge is driven into the pin after the
latter has been pushed forward as far as the tube cone, in order
to expand the pin and thus to clamp it in the guide. It is
advantageous to slit the pin for such a purpose.
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The pins shown in the embodiments are additionally so
constructed that they enable a specified tension to be achieved
between deflection unit and tube cone. A tension of specified
size can, however, also be implemented by ensuring that the
support feet (15) are withdrawn by the aligning device with a
specified force while the pins are being pushed forward to the
tube and while they are being fixed in position. After the
deflection unit has been released by the aligning device, the
elastic restoring force of the support feet (15) ensures the
desired tension force. It must be pointed out that it is not
necessary for three support feet (15) to be provided in the
deflection unit; a different number may also be possible.
The embodiment relates solely to a deflection unit.
Pins which can be moved and arrested in the manner described
can, however, also be used to retain other components in the
position adjusted, e.g. for magnetic multipoles, of the type
used for setting convergence and colour purity, for example. In
an application of this sort, the pins can be supported on the
tube neck, or on the deflection unit in front of it.
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