Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention is in the field of sink clamps 7 of the
kind used to hold a sink in position in a hole in a counter top,
by clamping a rim of the sink into sealing contact with the
counter-top.
Such a clamp is shown in Canadian Patent Application
Serial No. 405,816 (USSR 420,266).
BACKGROUND OF THE INVENTION
Sometimes, when a sink is installed, the hole in the
counter top is cut slightly oversized or out of shape. The
clamping pad or cup of the clamp is intended to lie flat against
the undersurface of the counter top, but when the hole is not
quite accurate the cup can lie partly-on and partly-off the
undersurface. This can cause the clamping screw to try to adopt a
misaligned or tilted attitude with respect to an arm of the
clamp.
When installing a sink, the plumber is inevitably in a
crouched position, often working at arm's length, and often he
cannot see at least some of the clamps that he is fitting to the
sink. Again, it can happen that he causes the screw to try to
adopt a tilted attitude, with respect to the clamp arm.
Due to manufacturing tolerances, the clamp, or the sink
wall, may not be quite straight, so that once again the screw is
caused to try to adopt a tilted attitude with respect to the
clamp arm.
BRIEF DESCRIPTION OF TOE INVENTION
It has been found that when the screw is biassed, for
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one of the above reasons, to a tilted position, the screw becomes
very stiff to turn. The plumber might therefore not draw the
clamp fully tight, such that water might leak under the rim.
In the invention, it is recognized that what is required
is a nut with a length of engagement on the screw of several
thread pitches, to overcome the premature failure problem; and
also that such a nut must be free to rock, at least to some
extent. In the invention, the fit of the screw to the nut can be
the kind of snug fit that is chosen by engineers when combining
the need for a large area of good metal-to-metal contact with the
requirement that the screw turns easily in the nut. The nut
itself can rock with respect to the clamp arm to allow the screw
and nut together to take up a tilted attitude, in unison; if they
should do so, there should be no tendency to the extra friction,
and hence to the extra wear in the screw thread.
Not just the fact of providing this facility whereby the
nut can rock, but the manner of providing it, is an important
aspect of the invention. If a sophisticated universal joint, for
example, were to be used between the nut and the clamp arm, then
the rocking facility would be achieved but the resultant product
would cost too much.
It is preferred to mount the nut loosely in a cage, and
to mount the cage loosely on the clamp arm. A simple sheet steel
pressing or stamping may serve as the cage. The cage may be
snapped into a punched hole in the arm. The cage may be so
shaped that it holds the nut captive both before and after the
cage is mounted on the arm, and also that the cage is itself held
captive on the arm.
Lowe
It happens that nuts held captive in cages are items
that find many uses in a wide variety of products. Caged nuts
are consequently offered as standard catalog items by many
specialist screw-fastener manufacturers. High volume production
means that such items are very economical, and it will be seen
from the ensuing description how economically a typical
proprietary caged nut may be used as a universal joint, and so
provide the ability of the nut and bolt to rock relative to the
clamp arm, as called for in the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
Figure 1 shows a rimmed sink being clamped to a counter
top;
Figure 2 is a section through a mounting means, on line
2-2 of Figure 4;
Figure 3 is the same section as that of Figure 2 but the
mounting means is more misaligned;
Figure 4 is a section on line 4-4 of Figure 2;
Figure 5 is the same section as that of Figure 4, but
the mounting means is more misaligned.
In Figure 1 of the drawings, a sink 11 is to be secured
through an opening in a counter-top 13. The sink 11 has a rim 15
which is to be sealed to the counter-top 13. Clamps 17 are
provided to draw the rim 15 down onto the top surface 19 of the
counter top 13, to maintain that sealed condition.
A clamp 17 is provided with an offset tab 31. The tab
31 enters a slot 33 created between a welded-on bracket 35 and a
side-wall 37 of the sink 11.
The clamp 17 includes a leg 39 and an arm 51. A screw
53 is mounted to the arm 51 by means of a mounting means 55 which
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will be described in detail presently. The screw 53 is capped by
a pad comprising a cup 57 with serrated edges. The end of the
screw 53 is staked over, to hold the cup 57 captive on the screw
53.
When the screw 53 is tightened, the cup 57 engages the
undersurface 59 of the counter-top 13. Further tightening causes
the tab 31 to settle tightly into the slot 33, and thus
ultimately causes the rim 15 to be drawn tightly against top
surface 19 of the counter-top 13.
lo The screw 53 is in threaded engagement with a nut 71.
The nut 71 has substantial thickness, being several times thicker
than a pitch 73 of the thread. The length 75 of threaded
engagement of the screw 53 in the nut 71 is several pitches long.
The nut 71 is square, and mounted in a cage 76, made of
sprin,~-steel in sheet-form. The cage 76 has springy side walls
77, which are spaced somewhat from the sides of the nut 71 such
that the walls 77 can be squeezed towards the nut 71 to a certain
extent .
Each wall 77 ends with an in-turned tongue 79, which
carries a hook 91. A punched hole 93 in the arm 51 is square, and
is so dimensioned that when the side walls 77 are squeezed
together the hooks 91 pass through the hole 93, yet when the side
walls 77 are released they spring out so that the edges of the
hole 93 are caught between the tongues 79 and the hooks 91.
Hence, the cage 76, and the nut 71, are held captive to the arm
51, yet the cage 76 is loose with respect to the arm 51, and also
the nut 71 is loose with respect to the cage 76.
Due to the various circumstances mentioned, the axis 94
of the screw thread may lie misaligned at an angle 95 to the true
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normal to the arm 51. In other words, the axis 94 may be
regarded as being rotated through the angle 95 about an axis 96
which is itself normal to the axis 94. If the angle 95 is only
small, then one of the tongues 79 rests against the edge of the
hole 93 as the screw is tightened, as shown in Figure 2. If the
angle 95 is larger, the nut 71 tips free of the other of the
tongues 79: the maximum misalignment angle 95 occurs when the
condition shown in Figure 3 prevails, when both the cage 76 and
the nut 71 are tipped to their respective maximum extents.
The misalignment may be in a plane at right angles to
that shown in Figures 2 and 3. Now the angle 95 represents a
rotation of the screw axis 94 about the axis 97 which is also
normal to the axis 94 but is also normal to the axis 96. This
condition is shown in Figures 4 and 5.
(It may be seen from these figures that the cage 76 is
provided with tags 99 to keep the nut 71 captive.) The
dimensions of the tongues 79 and the hooks 91, and of the hole 93
in the arm 51, are such that again a two-stage tipping of the
screw axis 94 can take place, up to the maximum angle illustrated
I in Figure 5.
Thus, it can be seen that the manner of mounting the
screw-threaded elements 53, 71 to the clamp arm 51 gives rise, in
effect, to a universal joint, but a universal joint that is very
inexpensive. The caged nut just described is a commonly-
available fastener element, sold in many sizes and styles. The important aspect of its use is that the hole into which it fits
should be so dimensioned that after fitting both the cage and nut
are loose with respect to the arm.
