Note: Descriptions are shown in the official language in which they were submitted.
1093~Zl)
rhe l)rcs(n~ invcntion -rel~tes to a load-control switch-
;n(~ device. More particularly this invention concerns such a
swi1(h llsable in a step for a motor vehicle for controlling an
cle(tr;cal circuit in dependcnce upon lowering of the step.
This type of arrangernent is used in order to prevent opening of
the motor vehicle doors, ope-^atjon of -~he motor vehicle, or
withdrawal of ~he step when same is loaded.
This ~ype of switching d~vice normally comprises a
first support and an e]ement displaceable relative to this
support when loaded. Normally, ~his element is a portion of the
step and the support is a fixed part of the step or the motor-
vehicle body. A spr;ng urges the two members apart and a switch
is connected between them so as to close or open, depending on
the type of circuit being controlled, when the one part is moved
toward the other against the force of the spring. The spring
serves to return the elements to the unloaded position once the
load is removed and to prevent the weight of the one element
from actuating the switch all by itself. The spring can often
be adjusted so as to establish a threshold weight or lead that is
the minimum value necessary to actuate the switch.
Finally, various abutments are usually provided so as
to prevent the two elements from moving apart beyond a predeter-
mined spacing, and to define a loaded position for the two ele-
ments relative to each other. Such abutments are frequently
constituted as angle pieces connected to the various elements
and gripping behind each other.
The principal disadvantage of this sytem is that there
are several parts which must be all assembled together at various
locations so that the overall cost is elevated. Furthermore, the
~ y - 2 -
lV~6ZV
1 switch and abutments are frequently liable to fouling due to the
mounting of such a step underneath the motor-vehicle chassis.
It is therefore an object of the present invention to
pxovide an improved load-control switching device.
Another object is to provide an improved load switch
usable in a motor-vehicle step.
Yet another object is to provide such a switching device
which is extremely simple, yet which has a long service life.
A further object is to provide an improved load-operat-
ing switch which can simply and easily be adjusted so as to varythe load-weight threshold, as well as the loaded and unloaded posi-
tions of the pair of supports between which the switch is connect-
ed.
These objects are attained according to the present in-
vention in a load-controlled switching device which is connectable
between a pair of supports displaceable toward each other and
which has an outer hollow member mounted on one of the supports
for displacement therewith and an inner hollow member which is
mounted on the other support and displaceable therewith. These
members define a closed chamber and are telescopable between an
unloaded position with the supports relatively far apart and a
loaded position with the supports relatively close together.
Means is provided including a first set of abutments on the members
which are operatively engageable in the unloaded position to
prevent the members from telescoping apart beyond this unloaded
position, and means is provided including a second set of abut-
ments on the members operatively engageable in the loaded position
for preventing these members from telescoping together beyond the
loaded position. A spring in the chamber is braced between the
members and urges them into the unloaded position. A switch is
~t~36~,
1 carried on one of the members in the chamber and an actuator is
carried on the other of the members and is juxtaposable with the
switch to operate it.
According to further features of this invention the out-
er hollow member is a tube having at one end an outwardly directly
directed flange which is secured to one of the supports and on its
other end an inwardly projecting collar that cooperates with an
outwardly projecting collar on the inner member and forms there-
with the first set of abutments. In this arrangement the inner
member is of U-section.
Between the two telescoping members there is provided a
synthetic-resin relatively noncompressible sleeve having an outer
surface sliding along the inner surface of the o~ter tube and an
inner surface sliding on the outer surface of the inner member,
One end of this sleeve is axially engageable against one of the
collars and the other end against the other collar so as operative-
ly to interconnect them and to define the unloaded position.
According to yet another feature of this invention the
inner member is threaded into a ring secured to the other support
and can be axially screwed within this ring for adjustment of the
unloaded position of the arrangemen , One surface of this ring
which forms part of the inner member has an end face operatively
engageable with an end surface on the outer member, these two end
surfaces constituting the second set of abutments. In order to
adjust the loaded position the outer member itself is threaded
within a ring secured to the one support so that axially screw~ng
of this outer member allows adjustment of the loaded position.
In order to obtain a relatively noise-free and smooth
operation of the device there is provided in accordance with yet
another feature of this invention an elastomeric bumper ring be-
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1 tween the above-mentioned end surfaces, This bumper ring there-
fore cushions the two members relative to each other and greatly
increases the service life of the switching device.
In order to adjust the force needed to actuate this
arrangement the spring is braced at one end against one of the
hollow members and at the other end against a support plate carried
in turn on one end of an internally and externally threaded sleeve
passing through the other member, The sleeve can, therefore, be
screwed in or out to adjust the stressing in the spring. Further-
more, the actuator may constitute a screw threaded through thecenter of this sleeve so that screwing of this actuator in and out
will determine the point at which the switch carried on the other
member will be actuated. If the threads on the inside and outside
of the spring-adjusting sleeve are of the same pitch it is possible
to arrest the screw and adjust the spring without changing the
setting of the actuator.
According to further features of this invention the
screw itself is formed with a longitudinally through-going hole
so that a probe or test pin can be passed axially through this
screw in order to operate the switch and test the arrangement.
A cuff has one end connected to one member and another end connect-
ed to the other member so as completely to enclose all of the abut-
ments and the internal mechanism of the switch. Thus an extremely
long service life can be obtained.
With the switch according to the present invention all
of the various parts are housed in an out-of-the-way manner that
ensures that they will not be exposed to potentially damaging con-
ditions. Furthermore, all of the various positions and parts of
the arrangement can be adjusted relatively easily without dis-
assembly of the arrangement. In addition, the switch device initself can constitute the guide and support for the movable part
-- 5 --
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1 of a motor-vehicle step on the motor-vehicle frame, as the tele-
scoping arrangement ensures both good lateral and axial guiding
of the movable element.
The novel features which are considered as characteristic
for the invention are set forth in particular in the appended
claims. The invention itself, however, both as to its construc-
tion and its method of operation, together with additional objects
and advantages thereof, will be best understood from the following
description of a specific embodiment when read in connection with
the accompanying drawing.
The sole Figure of the drawing shows in axial section a
switching device according to the present invention.
As shown in the drawing a switching device according to -~
this invention basically comprises an outer hollow body 1 secured
to a step plate 11, an inner hollow body 2 secured to a body part
12, and a spring 3 urging them apart. An actuator 4 is carried
on the inner part 2 and serves to operate a proximity switch 5
carried on the part 1.
The part 1 is formed of an outer tube la having a flange
lb secured to the plate 11 and formed at its lower end with an in-
wardly projecting collar lc. In addition the outer member 1 com-
prises a plug ld threaded into the tube la and in turn carrying
the switch 5 which may be of the reed type. The spring 3 bears
at one end on the annular plug ld which is formed with axially ex-
tending holes allowing a wrench to be fitted to it,
The element 2 is of U-section and comprises a ring 2b
having a flange 2c screwed to the plate 12, Threaded within this
ring 2b like the plug ld is a tube 2e coaxial with the tube la
and having an upper end formed with an outwardly projecting collar
2a.
-- 6 --
1(~ C~
1 Tlle collar~ 2a and lc together form a set 7 of abutments
t~
between which is erlg-ged a Teflon ring ~ whose inner surface is
slidable Oll the sleeve 2a, whose outer surface is slidable in the
sleeve la, and whose ends engage the collars 2a and lc. Thus this
ring 8 which is relatively incompressible defines a force-transmit-
ting member between the set 7 of abutments. Since the spring 3
urges the members 1 and 2 apart the unloaded rest position of this
assembly is therefore established by this set 7.
The upper end 2d of the ring 2b of the member 2 is opera-
tively engageable with the lower end surface le of the element la.These two surfaces 2d and le lie in respective planes perpendicular
to the axis of the device and constitute a set 6 of abutments that
define the loaded position of the arrangement. An elastomeric square-
section ring 9 rests on the surface 2d and surrounds the tube 2e so
that when the elements 11 and 12 are moved rapidly toward each other
the surfaces le and 2e will not strike noisily together but will be
cushioned by means of this elastomeric ring 9.
The actuator 4 comprises an internally and externally
threaded sleeve 4a screwed into the central hole in the sleeve 2e
and having an upper end carrying a washer or disk 4c on which bears
the lower end of the spring 3. Thus, it is possible to adjust the
compression force in the spring 3 by screwing the sleeve 4a into
and out of the sleeve 2e which may be held nonrotatably by means of
appropriate countersunk formations in its exposed end. Threaded
within the sleeve 4a is a screw 4b constituting the actuator for
the proximity switch 5 whose leads extend upwardly out through the
plate 11. The proximity switch 5 is of the type shown, for example,
lV936ZO
in the catalogue "Wechselspannungs, Pulsoren, Zylinder-Bauform,
Quader-Bauform'70f P~,SO7I7RONIC, Federal Republic of Germany. ~he
switch has at its end opposite to the lead, an electromagnetic
field. When in normal operation a metallic body is introduced into
the magnetic field, particularly the screw 4b, the switching process
starts. In addition the screw 4b has an axially throughgoing
hole 4d which allows a probe or pin to be pushed through this
screw to actuate the switch 5 to test this switch. The inter-
nal and external threads on the sleeve 4a are identical
. . .
:
- 7a -
10~3~
1 so that it is possible to grip and arrest the screw 4b while
rotating the screw 4a in order to adjust the compression of the
spring 3 independently of the position of the screw 4b.
A flexible cuff 10 has one end secured to the member 1
at the outside surface of the tube la and another end secured to
the outside surface of the ring 2b. This cuff 10 therefore
prevents any dust or foreign bodies from entering into the arrange-
ment, but permits a relative axial motion of the various parts
with these.
With the switching device according to the present in-
vention it is therefore possible to adjust the actuation position
for the switch 5 by screwing the actuator 4b in the-sleeve 4a.
Similarly both the actuation position and the compression of the
spring 3 can be adjusted by screwing the plug ld in the tube la,
or the spring compression can be adjusted independently of the
actuation position by rotating the sleeve 4a-while holding the
sleeve 4b from rotation. The illustrated unloaded position of
the device can be adjusted by screwing the sleeve 2e in the ring
2b.
Thus the switch according to the present invention is
completely closed so that it will have a long trouble-free service
life. At the same time it can readily be adjusted from one end
and any of its parts can easily be withdrawn and replaced if de-
sired.
It is possible to simplify construction by forming the
two elements la and ld as a single piece. To do this, therefore,
it will be necessary to tooth the collarc 2a and lc in order to
allow them to be fitted together bayonet-fashion.
It will be understood that each of the elements describ-
ed above, or two or more together, may also find a useful appli-
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1 cation in other types of structure differing from the types
described above.
While the invention has been illustrated and described
as embodied in a switching device, it is not intended to be limit-
ed to the details shown, since various modifications and structur-
al changes may be made without departing in any way from the
spirit of the present invention.
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