DE2322829A1 - HAND EXTRUDING DEVICE - Google Patents

Description

DR. MOLLER-BORI: '3IPU-PHYSa-ORMANITZ DlPu.-CHEM. DR. DEUFEL DIPL.-INQ. DARK FOREST. DIPL.-ING. GRÄMKOW

PATENT LAWYERS

GN / ca. - H 115β

"? · May 1973

HAEDNAJT, INC »
6000 Cortland't Street, Belleville, New Jersey USA

Hand extrusion device

The invention relates to an extrusion device, in particular a hand-held device for extruding materials with thermoplastic properties.

So-called polymeric sealing materials are thermoplastic rubber-based mixtures which are used more and more for sealing purposes, for example where it is desired to create a seal between a glass Y / ind shield and a matching frame of an automobile. Such mixtures can be used, for example, on the? Polymerized butyl base include oiex on poljsulphide polymers, on styrene

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ORIGINAL INSPECTED

Butadiene-KRUtachukpolymerea, on aerylnitrile-butadiene-rubber polymers or other butyl rubbers Neoprene, urethanes or combinations of these various components and / or other synthetic compounds based on rubber »

In the course of the use of such materials, the primary goal which the artisan seeks to achieve is to lay a string of sealant in a prescribed pattern on one of the surfaces to be joined. Said material is commercially available in rope-like form and, in order to provide a desired well-defined cord, devices have been proposed from time to time which, in one way or another, squeeze out the sealant under operator control. When the grading means thermoplastic Matür is an excellent string is placed, if the material is first heated wlrd ₉ ao dal dea extrudate dl · area "in the. it is deposited, can moisten and otherwise firmly adheres to it. For this reason it has been proposed in certain of the above mentioned devices that heating be provided during the extrusion process.

While the devices referred to above are used commercially to a large extent, they have nonetheless proven themselves has proven remarkably ineffective and unreliable in practice. For the failure of these devices to meet commercial needs, one can A series of causes are given. Between such Inadequacies are the failure of these known devices in providing sufficiently controlled and uniform heating of the extrudate, as a result of which the product created was very uneven for its uniformity

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was missing and did not adhere well. In many cases it was furthermore, the configuration used to achieve heating is such that random heating is introduced into operator-grasped parts of the device became what was consequently unpleasant and dangerous.

Such devices, as they are currently available for the above purposes, are also relatively inadequate with regard to the feed mechanism used for the sealing material. In particular, the material is often fed at a preset rate and repeatedly difficult for the operator to both operate the feed &% b of material and control the feed rate. It can also be noted in this connection that there is a particularly difficult problem where the user of such a known device changes from a first type to a second type of sealing material, which subsequent material may be of a different color or with different physical properties . With the known devices mentioned above, it is expedient under these circumstances to carry out a complete evacuation of the device. Since it is usually not practical to disassemble the whole apparatus, it is common to add large quantities of new material before the contamination from the previous material is removed, with consequent and obvious waste.

In accordance with the foregoing, it can be considered an object of the present invention to provide a handheld extaric device for applying thermoplastic sealing materials made by US Pat an operator can be easily held and operated and which is provided with a device which

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accurate and uniform heat control for the extrudate enables.

It is another object of the invention to provide a handheld Device for the extrusion of thermoplastic sealing materials to create which are effectively divisible Speed device for feeding the Contains materials that are uniform and very provides regulated heating of the extrudate, and the moreover heating and electrical hazard to the operator minimized.

It is a further object of the invention to provide a hand-held extrusion apparatus for thermoplastic sealing material to create, which creates easily replaceable running parts, whereby an operator the Device configuration for pressing successive types of different materials easily can change and avoid contamination.

In accordance with the invention, the foregoing and other objects as will become apparent from the following description are achieved by a hand-held device having a barrel with a feed passage extending therethrough and a number of heater element passages extending parallel to the feed passage . A feed screw is rotatably provided in the supply passage with a motor means attached to one end of the barrel block 1st and is operated by a trigger on a Fistolengriff which 1st connected to the motor means.

The invention creates a hand-held Extrudiervor-

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direction for applying thermoplastic sealing materials. The apparatus includes a barrel with a material feed passage extending through the container. A number of heating element passages are parallel with rod-like heating elements mounted therein to the feed passage. A heat sensor is located in another parallel passage in the barrel and the sensor is provided together with the heating elements in a control circuit that enables a preselected temperature to be adhered to exactly. Material introduced into the barrel is turned into a by a motorized auger opening · advanced at the outlet of the feed passage. The barrel is on a pistol grip and a housing part attached to the device in a way that allows the interchangeability of the barrel and the heat transfer from the barrel to the handle and the housing mlnimalized.

The invention is described below by way of example with reference to the drawing; in this shows

1 shows a longitudinal section through the hand extrusion device according to the invention;

1A shows a partial section of the contact arrangement at the interface between barrel and socket parts the device according to Fig. 1;

Fig. 2 shows a plan view of the device according to Fig. 1;

Fig. 3 is a front end view of the device according to Fig. 1;

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Figure 4 is a section along line 4-4 in Pig. 1, which contains the external electrical connections in Towards the inlet end of the device container shows;

Pig. Figure 5 is a top plan view taken along line 5-5 of Pig. 1, which is the external appearance of the control panel and shows the associated components in the housing part of the device;

Pig. Figure 6 is a partial sectional view of the barrel portion of the device;

Pig. 6A and 6B are end views of the barrel; Pig. Figure 7 is a plan view of the barrel;

Pig. 8 shows a longitudinal section through the barrel bushing part of the device;

Pig. Figures 8A and 8B are end views of the socket;

Pig. 9 is a plan view of the barrel bushing; and

Pig. 10 a simplified electrical circuit diagram

of the temperature control circuit used in the device.

Pig. 1 shows a longitudinal section through a hand extrusion device 20 according to the invention. In explaining the pig. 1 is a notice of the Pig. 2 and 3 two-mass. Xn Pig. 1 , the device 20 is shown with a barrel which is connected at its inlet end to a housing 26 by a barrel bushing 46. The run 22

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is connected at its outer end with a cap 25 which is provided with a nozzle 24 for distributing the material pressed out of the torrent. The barrel 22 is outside ▼ covered on an insulating sleeve 44, which is made of an asbestos composition or another high temperature insulator is formed. Similarly, a bushing 46 is formed from phenolic-based plastic or other material Relatively well insulated for heat transfer and conduction of electricity. These two elements therefore cover the main mass of the front part of the gate direction 20 and, as it will become more and more clear, serve to Preventing heat transfer from the relatively hot! Eetsllieohes barrel to the hands of an operator and also minimizes the risk of shock.

Housing 26 may be viewed as including a motor housing 28, a pistol grip portion 32, and a gear housing 30. A line connector 36 is available and when this is connected to an AC electrical outlet, this creates energy for all of the motor and Control functions in the door direction. The trigger 34 on the pistol grip 32 creates a pingertip control for the located in the housing 28 motor. You different parts of the housing 26 which have been described are conventional and commercially available structures of this type, which are used in conventional hand drills or similar, the primary purpose of these various components being to provide motive power for controlled rotation of the material infeed corner 50 (referred to below) supply and also provide connections for operating the heating elements and the associated control circuit part of the door direction. In accordance with such known configurations, it will be apparent to those skilled in the art that the motor of the housing 26 for an appropriate bo tation rate in accordance with the requirements

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to which device 20 is exposed in a given situation.

Returning to Pig · 1, there is shown a material feed passage 23 extending axially the length of the barrel 22 extends. You material screw conveyor 50 is in order to Rotation arranged in the passage 23. The screw conveyor 50 therefore ends with a shaft part 52 which is square or other cross-section with flat surfaces (such as polygonal), with the shaft in a matching opening 51 is mounted, which in a drive gear 54 is provided. The drive gear 54 », which is rotatable in a bearing 56, is the last force-transmitting one Part of the transmission located in the transmission housing 30 and therefore transmits the power from the drive system, which is in the motor housing 28 is. Material to be pressed out through the gate direction is fed through the feed opening 42 which both through the bushing 46 and through the barrel 22, which leads the bushing at such an axial point partially subject. Said material, which can contain the already mentioned polymer masses, is typically supplied in knitted form and is when touched the feed screw 50 conveyed through the passage 23 to the outer end of the erection. The nozzle 24, through which the material actually emerges is in engagement with a sap 25 by means of a thread 27. The sap 25, as best seen in Figure 3, is in turn connected to the barrel by a pair of screws 56 and 60 22, which rest through the cap in threaded sections 62, 62 (Fig. 7) of the passages 66 and 68, discussed further below.

As from Fig. 1 as well as from the detailed representations of the barrel can be seen in FIGS. 6, 6A and 7

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the barrel 22, in addition to the central feed passage 23, the pair of Heizdurchläsaen 66, 68, which are parallel to the feed passage 23 in an axially offset arrangement which laterally flank the feed passage. The heating passages 66 and 68 actually extend from the end of the barrel that connects to the socket 46 is, to the axial coordinates given in Pig. 1 is determined by point 70 which is near the exit end of the Run is. These heating passages, for example, are made from Pig. 6A can be seen, but are arranged at a slight distance from the feed passage 23 and it can be seen that the heat created in such passages can easily be transferred to the extrudate, which goes through the feed passage. Heat is therefore provided by a pair of elongated heating elements, one of which one can be seen at 72, those in passages 66 and 68 and typically extend from the clamp end 70 of such passages' to a point such as which is approximately the axial point at which material is introduced into the device. The mentioned Heating elements may typically include a refractory bonded heating element such as a so-called one Heating rod ("call rod") or other known fixed heating elements, which are two-dimensional and light as cylindrical or similar elongated bodies can be formed.

How best in the Pig. 1 and 6 can be seen., Is a fourth passage, parallel to the three passages previously explained, is provided in the barrel 22. This last one Element, heat probe port 78, is in Pig. 6A as containing a bore extending to each of the heating passages 66 and 68 by 90 degrees around the circumference of the barrel 22 is offset. The passage 78 extends over the

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whole length of barrel 22 and, as is best in Pig. 6 is in good thermal contact with the Feed passage 23 through the relatively thin wall 80. The Passage 78 is at its end near the cap 25 through a Ball bearing 82 closed, which is inserted with a press fit into the opening which terminates the passage at such a point.

In accordance with an important aspect of the invention is in the passage 78 a heat sensor 84 on an axial Point attached which is about two thirds of the length τοπ of the feed opening 42 in the direction of the output end of the Run lies. The button 84 typically comprises a PestzuBtands-Thermistor (solid state thermistor) which, as will be described in more detail below, with the heating elements in a suitable one Control circuit is arranged. In accordance with this aspect of the invention, one operator provides the door direction by using a temperature selection button (Pig. 3), the pointer 41 of such a button on a suitable one Reading on the setting plate 39, whereupon the control circuit works with the button 84 and the heating elements to maintain the selected temperature in the feed passage 23 in an accurate manner.

A key aspect of the invention arises from the fact that barrel 22, along with associated cap 25 and nozzle 24, are easily disassembled and disassembled the remaining parts of the gate direction 20 can be removed, whereupon another different barrel-cap-nozzle assembly (including the associated heating elements and the Heat sensor) can be arranged in place of the removed elements. The important part of the goal of such a measure results from the wishes of the craftsman

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the frequent use of different types of extruded material for different amounts of a given job or for consecutive jobs. For example, it can be beneficial or beneficial for a craftsman It may even be necessary to use an extrudate of a first color in a first part work and an extrudate of one second color in the same work. In the past this has been a confusing and not easily resolved problem since using the same device for both Materials, the various passages, etc., which were assigned to the first material, cleaned up beforehand had to be or because, according to an alternative, a large amount of the second material during the initial pressing through wasted cleaning the system. Since the nozzle 24 itself is screwed into the cap 25 at 27, Furthermore, nozzles of specific cross-sections or final shapes can be easily changed according to the requirements of a given job. The latter Special feature also enables damaged nozzles to be replaced in a useful way, which is important in that as the nozzles are often the cheapest part of the nozzle-bite set-up.

When temporarily disregarding the various electrical connections with the heating elements and the heat button on barrel 22 can be seen first (flg. 1), that the barrel is connected to the Best of the device 20 through the heat-insulating sleeve 46, on the previously Has been referred to. The bushing 46 can be seen in greater detail in Figures 8, 9, 8A and 8B. The socket thereafter has a threaded portion 86 that mates with a mating thread 88 on the adjacent end of the gear housing 30 intervenes. A wedge slot is provided at 89 transversely to the threaded part 86} the grub screw 48, which the housing

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30 (Fig. 2) penetrates, engages in such a slot when sliding the gate in order to secure the screwed-in socket in its arrangement.

As best in the end view in Pig. 8B, the socket 46 is provided with a pair of threaded bores 90, 92, which are offset from one another by an angular distance of 90 °; the axial arrangement of the bores can be seen from the bar position of the hole 92 in Fig. 3, When the barrel 22 is fully inserted in the socket, as As can be seen from the position according to Fig. 1, there is a pair of recesses 94, 96 (Figs. 6B and 7) directly in line with the threaded bores 90 and 92. In this regard, it should be noted that the entire barrel 46 actually for the purpose of correct angular insertion into the socket 46 is keyed by the action of a plurality of projections 98, 100, 102 and 104 (Fig. 6B) which mate with elongated slots 106, 108, 110 and 112 which mate in the inner walls of the socket 46 (Fig. 8B). The handle 40 is at the end which is the end to be gripped opposite, provided with a threaded part which is introduced into one or the other of the bores 90, 92 can be so that it can sit in one or the other of the recesses 94 and 96, whereby the barrel and the socket can be locked together. At the same time, the grub screw is screwed into the opening 90 or 92, which is not occupied by the handle 40, and locks itself in the same way when screwing in the recess 94 or 96 below, around the socket 46 and the barrel 22 to further secure one another. Depending on whether the operator for the door direction 20 Left or right handed, the handle 40 is attached in one or the other of the bores 90 or 92.

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With the foregoing in mind, it is clear (with further temporary omission electrical connections) that the barrel in use can be detached and removed, namely only by unscrewing the handle part 40, removing the Grub screw (not shown) from the bore 90 or 92 into which it is screwed, and then through the following Pulling the barrel out of its no longer secured position. Removing the barrel can actually do this be supported that the feed screw 50 is driven that when the barrel is no longer stuck in its Position is held, the rotation of the feed screw (assuming that a certain amount of extruded in the Barrel 22 remains), the extrudate presses against the limiting parts of the barrel and thereby the barrel forwards drives. It should also be noted that once the barrel 22 is moved in this way, if so desired, the Feed screw 50 can be removed because the latter to this tent only through the frictional engagement of the shaft part 52 with the matching opening 51 of the drive gear 54 is held.

The type of electrical connections between the heating elements 72 and the heat button 84 will now be described below. all of which are located in run 22 according to the previous explanations. First (with reference to FIGS. 1 and 1A) a plate 116 is attached to the entrance end of the barrel 22, which contains insulating layers or similar. This record is equipped with male (male) electrical contacts, such as those used for making electrical connections with the heating elements and the button 84 are useful. When the barrel in the bushing 46 is in its operative position, are the various male contacts of the plate 116 with female (female) plug-in contacts 116 in the socket

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46 engaged. Two such contact pins can be seen, for example, at 118 and 120, together with the line connections from the female receptacles in question lead to the drive part of the device. . As best in the cross-sectional view in Pig. 4 to see along line 4-4 in Pig. 1, a series of electrical connections is therefore provided. the Thus, the various wires entering the socket 46 through suitable passages comprise a neutral conductor at 122, connections to the heating elements at 124, '126 and 128, 130 and a pair of connections 132, 134 for heating the button 84.

As if from the broken part of the Pig. 1 and from the simultaneous review of the Pig. 4 can be seen the various wires 136 coming from a connector assembly 116 into the housing portion 26 of the device and into a male terminal 136 of a connector 144. The connector is a commercially available element such as for example an element of this type sold by Molex Inc. and the clamp 138 includes a beveled one Edge 142 which ensures a secure fit of the clip into a mating female clip. The thus Mating connector 144 is in Pig. 1 to include male clamp 138 and female clamp 146. Various wire connections 148 run in housing 26 downwardly from connector 144 to one end of a like one Connector 150, which in turn is connected with its opposite end to the power line to thereby creating a force input for the heating and control functions of the device 20.

As now with the examination of the broken part of the Pig. 1 can be seen as well as during the simultaneous examination of the

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Top view according to Pig. 5, the along the broken Line 5-5 in Pig. 1, an important advantage of the invention results from the fact that the entire Heater control circuit of the device is mounted on a control panel 154.

The switchboard 154 is secured by a spacer (etandoff) 156 carried by housing 26. A pair of screws are threaded into opposite ends of the spacer or through the adjacent wall of the housing and through the control panel 154. The head of one this screw can be seen at 158. The various that make up part of the heating control circuit Elements are in the plan view according to Pig. 5 shown outside; they are explained in terms of their electrical punctures in connection with FIG. 10; however, certain external ones Aspects of the mounting arrangement are from Pig. 5 can be seen, including, for example, the potentiometer 160, which is connected to the Temperature selection button 38 (already explained) durgh a rotatable shaft 164 is connected which extends through the housing 26. Also recognizable is the pear 166, which is arranged in the direction of the upper part of the control panel 154, so that the tip of the same through an opening 168 is visible, which is visible in the housing 26, next to the temperature selection button 38. The indicator light creates a visual signal to the operator indicating that heating of elements 74 and 76 is occurring. A triac 162, which forms part of the heater control circuit, extends downward from the bottom of panel 154. The central opening 163 therein is for the connection of such a Attachment to the inner wall of the housing 26 is used by a nylon screw 170. A thin mica insulation (not visible on the scale according to Pig. 1) lies between the triac 162 and the housing 26.

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Related to Pig. 5 it is to be noted in particular that the electrical connections with the Heizungs.-Steiirkreis, attached to the board by a female clamp 146 at the top of the pig. 5 and through one male clamp 171 is effected at the bottom of the figure. These both terminals are in contact with the respective connectors 144 and 150 which have already been described. Bs is It can be seen that one of the major advantages of this circuit arrangement is that in the event of failure of a circuit element or several Stromkrfeis elements, this becomes a simple repair process. In particular, the connection with the panel 154 can be at the Pair of connectors 144 and 150 are broken and then after loosening the the panel is in firm contact with it the screws holding the housing 26, the entire panel structure can be removed and replaced with a new, identical unit. As the various pest body components that are included in the control circuit, are relatively cheap, this simple replacement process is also economical; it not only enables repair of the device 20 by relatively unskilled personnel, but also speeds it up Such a repair also from a time point of view and therefore prevents downtime by far more expensive and valuable device 20 which includes the control panel.

Different from numerous known extrusion devices Of the general type to which the invention pertains, the present device is a equipped with a highly sensitive temperature control circuit, which, together with the extended heating elements already explained 74 and 76 and with the effectively arranged button 84 a very effective control of the heating of the extrudate causes going through the device. A united

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The four-fold diagrammatic representation of a control circuit suitable for such purposes is in Pig. 10 included. Of course, this circle corresponds to the "outer" Circle related to the Pig. 5 is mentioned.

Like from Pig. 10 it can be seen ', leads a power line on the pair of terminals 176, 178 to the control circuit. The load in the form of the heating elements is switched across the output terminals 180, 182. The heat sensor 84 ', which has preferably been mentioned above as a thermistor, is switched across the output terminals 184, 186. The flow of electrical heating energy to the load on terminals 180, 182 is controlled by a triac 162 which is connected between one of the terminals and one of the AC power lines. The heat sensing thermistor, together with the adjustable resistor 188 (corresponding to the potentiometer 160), forms one side of a bridge circuit, with the fixed resistors 190, 192 the other. Form side. The variable resistor 188 is set by the temperature dial 58 to the desired temperature level for the device. When the bridge due to T _e mperaturveränderungen in imbalance is to be determined at the thermistor, is an integrated circuit zero voltage switch 194 supplied a signal to actuate the latter and thereby the gate circuit of the triac 162 via the line 196 pulses at line frequency rate, which in turn cause the load to heat up. Resistor 198 is a biasing element which, together with resistor 188, provides a suitable voltage division to achieve appropriate potential levels for the associated inputs to switch 194. The AC input at terminal 178 is also shown as running through a dropout resistor 200 to the indicated bulb 166, which is

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re it s- has been explained. When the triac 162 conducts, so when the heating is actually effected, it is clear that the bulb 166 is also activated and provides a visual indication to the operator of the device 20.

The null bridge switch 194 is a well known commercially available device. One for the lying purpose a suitable model is available, for example, from Motorola Semiconductors under the designation "MFC 8070". Of the The detailed electrical circuit of the electrical switch is explained in the brochures available from the manufacturer. It is sufficient for the purposes at hand su know that the integrated monolith construction an internal voltage regulating section with a zener diode,

a threshold detector, a differential amplifier input stage for sampling the resistor bridge referred to previously _v and an output driver stage for triggering the triac 162. The various output terminals from switch 194 and in Pig. 10 made by the numerical designation used by the manufacturer} Terminal 2 is an input to the differential amplifier stage of the switch} Terminal 3 provides a reference input to the same stage} Terminal

4 leads to the collector of a pre-amplification transistor; Terminal 5 is the ground side of the zero voltage detection stage and terminal 7 creates the pulse output from the Auagange-Trelberstufe of switch 194. Terminals 6 and 8 belong to the internal regulating part of the direct current power supply for circuit 174. Capacitor 202 is a power delivery capacitor that is connected to the diode regulators located in the switch 194 interact} the resistor 204 creates a suitable one Drop in line potential.

- patent claims -

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Claims (16)

Claims 1. Hand extrusion device for applying thermoplastic sealing compounds to surfaces, characterized by the following combination! a) a barrel with a feed passage extending longitudinally therethrough; b) a feed screw rotatably disposed in the feed passage; c) a motor device attached to the device for driving the feed screw, which on a Operator control responds; d) a number of heating element passages disposed in the barrel extending parallel to the feed passage; e) a number of rod-like heating elements arranged in the passages and extending over a extend a substantial part of the length of the passages therein; f) a heat sensor arranged in the block of the barrel for sensing the temperature in the environment the feed passage; g) a heating control circuit device that works with the Heating elements and the touch device for applying A09810 / 0343 energy is connected to the heating elements to maintain a preselected temperature on the barrel; h) means for supplying material to the supply passage; and i) an opening device at the exit end of the
Feed passage for discharging material. 2. Apparatus according to claim 1, characterized in that the motor device on a pistol grip housing is attached to the input end of the device. 3. Device according to claim 2, characterized in that that the barrel is covered by a heat and electrically insulating sleeve. 4. Apparatus according to claim 3, characterized in that the barrel by means of a thermal and electrical
insulating socket is connected to the housing. 5. Apparatus according to claim 4, characterized in that the barrel is exchangeable. 6. Apparatus according to claim 5 »characterized in that the opening device has a cap and one on this has releasably attached nozzle, whereby the nozzle is easily exchangeable. 7. Apparatus according to claim 5 »characterized in that the socket is screwed to the housing, that
the barrel can be slid in and out within the bushing that the barrel is in its outer wall 409810/0343 with a recess and the socket with a face this recess covering threaded hole are provided that a threaded element in this Bore can be introduced to the same when advancing, to lock the bushing and barrel with the Recess to get into engagement. 8. Apparatus according to claim 7, characterized in that the threaded element has the threaded end has an elongated handle for the device .. 9. Apparatus according to claim 8, characterized in that a pair of the depressions and the bore is present, and that the elements of each pair are angularly offset from one another on the alternating lengths of the vertical plane of the device, whereby the grip in one or the other of the holes eaae, according to the left or right handedness of the operator for the Device can be screwed in and further characterized by a grub screw which is inserted into the Bore and recess without being in engagement with the handle to reinforce the locking of the socket and .Barrel can be screwed in. 10. The device according to claim 9, characterized in that the motor is put into operation by a trigger switch located on the pistol grip and its Speed is adjustable. 11. The device according to claim 10, characterized in that that an electrical connection device is provided at the input end of the barrel, which of the heating control circuit when the barrel is pushed out of the socket. 409810/0343 12. The device according to claim 11, characterized in that that the heating control circuit is formed on a control panel which is detachably attached to the housing. 13 · Door direction according to claim 1, characterized in that that in the barrel a heat probe passage is formed parallel to the heating element passages, and that the Heat sensor contains a thermistor, which is in the Button passage is arranged in sighting at the exit end of the gate direction. 14 door direction according to claim 13 * characterized in that that the control circuit contains the following! Sine cons » Stand bridge with a thermistor contained in one side of the same and an adjustable resistor according to the selected temperature as well as on the other side of the same a pair of reference resistors, a triac * which is connected in series with the heating elements and an integrated Sehaltkreis-Äull-Ireuz switch which between the bridge output and the triac is connected to actuate the triac at line frequency in accordance with a signal generated by imbalance of the Bridge is provided for the switch, creating an on-off control for the heating elements. 15. Gate direction according to claim 14 »characterized in that there is an indicator lamp in parallel at the output of the triac is connected to the heating elements in order to create a visible display of the Bcheizen of the Siemeste. 16. Door direction according to claim 14, characterized in that a heat and electrically insulating sleeve Barrel covers, and that the barrel can be detached from the housing by means of a heat and electrical insulating letter connected is. 4 0 9810/03 A3 Blank page