Note: Descriptions are shown in the official language in which they were submitted.
'l'he pre~ent invention is d:irec-ted to a device for the
melting and measure(l discharge of a thermoplas-tic adhesive where
tne device includes a housing containing a handle with a least
two controllable heating stages with:Ln the housing.
Thermopla~tic adhesives are being used increasingly in
the fastening art. The advantages of such adhesives involve a
rapid loading capaci-ty, lack of volatile solvents or solvents
which are damaging to the health, with the further possibility
of loosening a connection effected with the adhesive by heating
,the connection~ In addition to manufacturing processes for
adhering parts, such as in the shoe industry, fusion adhesion
can also be effected in assembling parts. In such procedures
the problem occurs that there are relatively long interruptions
between tne individual applications of the adhesive material.
If the aevice is turned off during such interruptions, then a
relatively long start-up is required until the device again
reaches its operating temperature.
:
In one known device, the time to heat up to the operational
temperature is effected intwo stages. Initially, heating takes
~ place up to a certain temperature employing a higher temperature
:
heating stage. Once the certain temperature is reached, then a
switching operation occurs by means of a thermal circuit
component and a lower temperature heating stage becomes operative
.
providing only the melting heat required for the discharge of the
adhesive.
.
If there is no discharge of the melted adhesive for a
lon~ period of -time, then there is the danger that the device
mignt overheat. To prevent overheating, the device must always
be turned off when a long interruption in use is expected. The
opeFator must decide each time whether the interrruption will be
- 1 - .
~.~
~ IL5~L9'~
long or short so that, if necessary, the device can be
turned off. Often, such a de-termination is difficult to make and
involves additional work for -the operator. If the device is
switched off more often than necessary, then unnecessary heating
up periods result. If, on the other hand, the device is shut
off too se]clom or not at all, there is the danger of overheating.
Therefore, it is the primary object of the present invention to
provide a device for melting thermop]astic adhesive so that the
device does not overheat or cool down too much during interruptions
in its normal use~
In accordance with the present invention, the device
includes control means in a pistol grip-like handle so that,
when the handle is released from the hand of the operator, the
higher temperature heating stage is cut out while a lower
; temperature heating stage becomes effective.
When using the device embodying the present invention,
the operator is relieved of any decision whether to switch the
device off during interruptions in its use. Another significant
advantage is that the device does not cool off completely, rather
~20 it continues to operate at a lower temperature which is not
damaging to the adhesive material or to the structural parts of
the device. ~Consequently, the time required to return the
device to the operating temperature is very short.
Basically, any circuit components, such as switches,
pre~ssure members or the like, can be utilized for switching
between the heating stages. Since such components usually have
projecting parts and are subject to mechanical wear, it is
-:
advantageous to position the sensor in the handle of the device
50 that it~reacts to the operator's touch. Accordingly, the
~30 switching process between heating stages is triggered when the
- 2 -
:~ :
'
~15~
opera-tor's hand contac-ts -the handle and merely touches -two
components. Such sensors are used at the present time in
electronic games and, therefore, are very economical parts.
During normal working operations with a device for
applying melted adhesives, often only very short interruptions
are encountered, such as when a part must be placed in a certain
position. When this is belng done, the device i.5 placed a~ide
for a short period. To avoid a changeover between heating stages,
it is practical if the switch from the higher temperature to
lower temperature heating stage takes place with a time delay.
In this way unnecessary waiting time for reheating can be
prevented.
The various features of novel-ty whlch characterize ~he
invention are pointed out with particularity in the claims
annexed to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its use, reference should be had
to the accompanying drawings and descriptive matter in which
.
there are illustrated and described preferred embodiments of the
illvention.
IN T~E DRAWING-
_
The drawing is an elevational view of a device embodying
the present invention.
In the drawing a device for melting a thermoplastic
adhesive and for discharging measured amounts of the melted
adhesive consists of a housing 1 with a handle 2 affording a
pistol-li]ce grip. The handle 2 depends downwardly from one end
of the housing 1. An electric supply line 3 is connected to the
handle 2 as well as a pressure actuated trigger member 4. When
' the trigger member 4 is pressed inwardly, a body 5 of adhesive
.
3 -
L94~
material, in the Eorm of an elongated cylindrical rod, is
conveyed by a transport device, known per se and not shown, in-to
a melting chamber, also not shown, located within the housing.
As a par-t of the cylindrical rod of adhesive material is moved
into the melting chamber a part of the rnelted adhesive is
discharged through an output nozzle 6 at the front end of the
housing 1. On the opposite side of the housiny 1 away from the
handle 2, ventilation slots 7 are arranged fox cooling the
device. In the side of the handle Z gripp~d by an opera-tor is
a sensor 8 for switching betwéen the higher -temperature heating
stage and the lower temperature heating stage. When the operator
grasps -the handle 2, his hand encloses the handle and -touches the
sensor 8 with the device automatically being switched to the
higher temperature heating stage. When there is an interruption
in the use of the device, and the operator releases his grasp
on the handle, such releasing action causes the sensor 8 to
switch from the higher temperature heating stage to the lower
temperature heating stage.
~aving described what is believed to be the best mode
by which the invention may be performed, it will be seen that the
invention may be particularly defined as follows:
Device for melting thermoplastic adhesive and for the
: . ~
measured discharge oE the melted adhesive including a housing
within which the adhesive is heated and from which it is
.
discharged, said housing having an outwardly extending pistol-
ke handle, said housing containing at least two controllable
heating stages including a higher temperature heating stage for use
when the device is operating for adequately melting and discharging
the melted adhesive and a lower temperature heating stage for
30; heating the thermoplastic adhesive to a tempera-ture so that the
- 4 -
: .
~4~ ~
higher temperature heating stage quickly raises the -temperature
of the melted adhesive whereby it is ready for use, wherein the
improvement comprises, control means located in said handle for
switching to the higher temperature heating stage when said handle
is held for operatiny the device and applying melted adhesive,
and for switching from the higher temperature heating s-tage to
the lower temperature heating stage when said handle is released
during a temporary interruption. in the use of -the device.
The invention further comprises such a device, wherein
said control means comprises a sensor located in the surface of
said handle so that the sensor reacts to the touch of the operator's
hand when he grips the handle for operatiny the device.
The invention Lurther comprises such a device, wherein
said control means includes a delay for delaying the switching from
the higher temperature heating stage to the lower temperature
~ heating staye when said handle of the device is released by the
; ~ operator.
; ~ While specific embodiments of the invention have been
shown and described in detail to illustrate the application
:~2.0 of the inventive principles, it will be understood that the
invention may be embodied otherwise without departing from such
; principIes.
:
:
~ .
- 5 -
,
