Abstract:
The blocking device is intended for a cylinder lock ( 1 ) with mechanically coded tumblers and an electric coding. An installation unit ( 22 ) comprises an electrically driven control ( 14 ) with a helical drive unit ( 16 ). The helical drive unit ( 16 ) is connected with an additional blocking element ( 13 ), which can engage and disengage the rotor ( 10 ) of the cylinder lock ( 1 ). The helical drive unit ( 16 ) comprises a threaded track ( 39, 61, 65 ) closed at both ends. A control device ( 17 ) generates the control signals for the driving or the energy supply to the control ( 14 ). The method of construction according to the invention makes possible a compact type of construction and has improved security against unauthorized interference from the outside.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a blocking device for a cylinder lock with a stator, a rotor rotatable in this stator by means of a key, an additional blocking element which can linearly engage and disengage the rotor along a displacement axis, and an electrically driven control means for actuating this blocking element, with the control means comprising a rotating driven end of the shaft, a helical drive unit, which is disposed between the control means and the blocking element, as well as an electric control device for generating control signals for the control means and a method for operating this device. 
     Blocking devices of this type are applied in locks, in particular in cylinder locks. In the case of cylinder locks it is known to provide mechanically coded tumblers between rotor and stator and additionally a mechatronic blocking device which blocks the rotor independently of the mechanically coded tumblers. Through this combination of mechanically coded tumblers with an electric or electronic coding, the security and adaptability of such locks or locking devices can be considerably increased. Such locking configuration is known for example from EP A 730 073. This locking device comprises in known manner a rotatable rotor, wherein this rotor is provided with a key channel, into which a flat key can be inserted. This flat key comprises on the key bit in a manner known per se mechanical codings, which cooperate with tumblers between rotor and stator. With the correct coding of the key, these mechanical tumblers can be unblocked and thus the mechanical portion of the locking device can be moved into the opening position. The key comprises additionally an electronic coding, which, in this example, includes a transmitter for information signals. As a counterpiece on the cylinder lock a receiver is disposed which receives the information signals transmitted from the key and supplies them to an electronic processing device. This electronic device controls an additional electromechanical latch whose blocking part can engage and disengage the rotor. This electromechanical latch comprises an actuation component or a control means for the blocking part. The control means can be known means for generating translational motions, for a example a magnetic drive or a rotating setting drive. In order to hold the blocking part in the blocking position and to secure it against unauthorized interference from the outside, a reset spring is available which presses the blocking part in the direction of the rotor. This is especially necessary in the case of blocking parts which are moved translationally by solenoid magnets, since here in the de-energized condition the control means does not exert any forces onto the blocking part. 
     The above described and further known locking devices with cylinder locks, which comprise, on the one hand, a purely mechanical coding and, on the other hand, an electronic coding with additional mechanical blocking elements, for their orderly actuation or unblocking, a mechanically correctly coded key and an electronic module on the key, which exchanges information signals or data with an electronic module in the cylinder lock. This data exchange can take place through direct contact elements or free of contact via a transmitter-receiver system. If the electronic module on the key contains the correct data, the electronic module in the cylinder lock accepts this key as being authorized for opening and releases the additional blocking device. In spite of this twofold coding and increased security, the known electromechanical or mechatronic locking devices which can still be interfered with sufficient expenditure through magnetic forces, vibration or impacts or by combinations thereof. 
     In borderline cases this can lead to the fact that such a locking device can also be opened without authorization without keys with matching electronic coding. Of disadvantage with locking devices with cylinder locks of this type and with an additional electronically controlled blocking element is also the fact that the additional blocking element and the corresponding control means, have dimensions, in particular with the actuation by a solenoid magnet which are greater than the normal housing of commercial cylinder locks. Therefore additional housings are necessary and the corresponding locking devices cannot be applied in standardized, normally utilized lock boxes on doors or other objects. In order to make installation possible additional adaptations and changes are necessary. 
     In the mechanical coded cylinder locks, which are used for example with rotary grip locks or cylinder olive-shaped handles for rotary rod locks, it is known that the structural dimensions can be reduced if the blocking element is actuated via a helical drive unit. These known actuations of blocking elements through helical driving however, are not able to solve the problem of unauthorized unlatching by actions from the outside. WO 98/28508 discloses a solution which essentially employs an additional electromechanical latch, such as is described in EP A 730 073, in which inter alia for generating the movement of the blocking element a control means with different types of helical driving is proposed. In order to counteract unauthorized interference from the outside onto the blocking element, additionally reset means and/or force transmission means are necessary, which are said to counteract or neutralize forces potentially applied from the outside. These reset and force transmission means are essentially disposed on the control means approximately at right angles to the longitudinal axis of the threaded drive, whereby either radially or parallel to the longitudinal axis of the cylinder lock additional space is required. This device can therefore also not be installed into the housing of normal cylinder locks, but rather additional annular housing or longitudinal housing components are necessary. 
     Due to the large number of requisite parts and their differing axes of action, the assembly and installation of this blocking device is complicated and costly and often requires additional adaptations in the installation region into an object, for example into a lock box and/or a door. 
     The present invention addresses the problem of providing a blocking device for a cylinder lock with an additional mechatronic blocking device in which this additional blocking device can be installed into a standard lock housing, for example into its crosspiece, simultaneously the unauthorized unblocking through interference from the outside is virtually prevented and the additional blocking device is structured as a compact structural unit in simple manner and with a minimum number of parts. The additional blocking device for a cylinder lock is furthermore developed as a kit which makes possible the retrofitting of mechanically coded cylinder locks and it will, moreover, be applicable in different systems of cylinder locks. 
     This problem is solved in terms of device through the characteristics defined in the characterizing clause of patent claim 1 and in terms of method according to the characteristics of the independent method claim. Advantageous further developments of the invention are evident based on the characteristics of the dependent patent claims. 
     In the blocking device according to the invention the driven end of the shaft of the control means, the rotational axis of the helical drive unit, as well as the blocking element and its linear guidance are disposed on a common longitudinal axis, or these elements have a common axis. This disposition yields the advantage that these elements can be combined to form a compact structural unit and a simplified method of construction is made possible. Due to the orientation of the rotational axis of the helical drive unit toward the common longitudinal axis, the rotary motion of the driven end of the shaft of the control means can be converted directly into the linear motion of the blocking element without additional elements, such as reset means of force transmission means being necessary. 
     The helical groove which is disposed on a first portion of the helical drive unit, along a shell surface about the common longitudinal axis, has a positive pitch over a certain predetermined segment and forms therewith a coil-form ramp, similar to a threaded worm. The helical groove has a certain length, which with the pitch determines the linear stroke travel of the helical driving. The two end regions of the helical groove are terminated by stop faces and determine, on the one hand, the blocking position of the blocking element and, on the other hand, the opening position of the blocking element. In the blocking position the blocking element has engaged into the rotor and blocks it relative to the stator. In the opening position the blocking element does not extend into the rotor and is disengaged from it. At least at that end region of the helical groove, which determines the blocking position of the blocking element, an additional longitudinal element of the blocking groove is disposed which exhibits no pitch. This longitudinal element without pitch is in a radial plane with respect to the longitudinal axis. A slide element disposed on a second portion of the helical drive unit, which engages the helical groove, in this region of the helical groove without pitch is form-fittingly and without action of force held in the direction of the common longitudinal axis. In connection with the characteristic that either the first portion of the helical drive unit with the helical groove or the second portion of the helical drive unit with the slide element is fixedly connected with the blocking element, the advantage is obtained that the blocking element in this end region of the helical groove, i.e. in the blocking position, is also held form-fittingly and without action of force. Usefully, the second end region of the helical groove is also provided with an additional longitudinal element, which does not have a pitch. Thereby the advantage is attained that in both end positions of the helical driving the blocking element is held through an operative connection between the helical groove and the slide element, which cannot be affected through external interference from the outside. In this implementation of the blocking device, such external interference such as magnetic forces, vibrations, impacts or resonance oscillations cannot displace the blocking element from the blocking or opening position. Unauthorized actuations of the blocking device are therefore virtually impossible. If on an end region of the helical groove with positive pitch or at a longitudinal element of the helical groove without pitch, an additional longitudinal element of the helical groove with negative pitch is annexed, an additional improvement of the security results since in this case, for example during an unauthorized attempt to displace the blocking element from the blocking position into the opening position, first an oppositely directed motion would have to be generated. The linear displacement travel of the blocking element from the blocking position into the opening position, and conversely, can be adapted in extremely simple manner by changing the length and/or the pitch of the helical groove to the desired conditions. Due to the direct coupling between helical drive unit and blocking element, the stroke travel of the helical driving corresponds to the linear displacement travel of the blocking element. Since at least in the blocking position no additional holding and reset forces act onto the blocking element, this end position is determined only by the forced guidance of the slide element in the helical groove and is uniquely determined by the form-fitting holding. 
     The blocking device according to the invention has further advantages since the elements of the helical drive unit and their connection to the blocking element, on the one hand, and to the driven end of the shaft of the control means, on the other hand, can be implemented differently. In a first advantageous implementation, the first portion of the helical drive unit is developed on the driven end of the shaft and specifically through a cylindrical structural part, in whose outer shell surface the helical groove is disposed. The second portion of the helical drive unit is formed by an end portion on the blocking element with an inner bore, wherein the slide element is disposed on the shell of this inner bore and projects radially into the bore. The cylindrical structural part on the driven end of the shaft extends into the inner bore at the end portion of the blocking element and is guided in this bore. The slide element extends therein into the helical groove on the outer shell of the cylindrical structural part and cooperates with it. The cylindrical structural part is connected torsion-tight with the driven end of the shaft of the control means and with rotational motions of the driven end of the shaft about the common longitudinal axis the cylindrical structural part is also rotated, whereby the slide element, and therewith the blocking element, is linearly displaced in the direction of the common longitudinal axis. The end portion of the blocking element is for this purpose secured against twisting in a manner known per se such that between the first and the second portion of the helical drive unit the desired conversion of the rotary motion into a linear motion takes place. A further embodiment of the helical drive unit comprises that the second portion of the helical drive unit is formed by the driven end of the shaft of the control means, wherein the slide element is fastened on this driven end of the shaft and projects radially outwardly. The blocking element also comprises an end portion with an inner bore, with the helical groove being formed into the shell surface of this inner bore. The end portion of the blocking element is slid over the driven end of the shaft and between the shell surface of the inner bore and the outer shell of the driven end of the shaft is formed a slide guidance. The slide element engages the helical groove and with rotational motions of the driven end of the shaft the blocking element is displaced through the cooperation of slide element and helical groove linearly in the direction of the common longitudinal axis. Here also the end portion of the blocking element is secured against twisting about the common longitudinal axis so that the conversion of the rotational motion on the control means into linear motions of the blocking means is ensured. In an especially advantageous development of the threaded drive, the blocking element is developed with an end portion which has a core bore and on whose outer shell surface the helical groove is disposed. Between the core bore of the end portion on the blocking element and the driven end of the shaft of the control means a slide groove connection is developed wherein, for example the driven end of the shaft is developed as a key shaft and on the shell surface of the core bore corresponding grooves are formed out at the end portion. This slide groove connection between blocking element and driven end of the shaft permits the transmission of the rotational motion of the driven end of the shaft onto the blocking element and simultaneously the linear displacement of the blocking element in the direction of the common longitudinal axis. The end portion of the blocking element is guided in a stationary sleeve with the slide element being disposed on the inner shell of this sleeve, which element projects radially into the bore of the sleeve and extends into the helical groove on the outer shell of the end portion of the blocking element. In this embodiment the sleeve and the slide element form the second portion of the helical drive unit and the end portion of the blocking element with the slide groove connection the first portion of the helical drive unit. This embodiment has the advantage that the sleeve can be developed simultaneously as the outer housing for the entire structural unit, which comprises the control means with the driven end of the shaft, the helical drive unit and the blocking element. This makes possible the preassemble of the structural unit, which can be placed as an overall unit into a corresponding bore on the cylinder lock and in simple manner can be connected with the electric lines. 
     The compact type of construction of the structural unit which is formed by the control means, the helical drive unit and the blocking element, and their orientation on a common longitudinal axis permits the installation of the blocking device into the crosspiece of a cylinder lock with the conventional structural dimensions. The outer form of the housing of the cylinder lock is therein retained and the cylinder lock with the additional blocking device according to the invention can be installed into the customary installation openings on installation objects, for example a lock box. This leads to considerable simplification since, on the one hand, a cylinder lock with the blocking device according to the invention can be completely set up and produced functionally ready at the factory and, on the other hand, no additional measures are any longer necessary when mounting it at the construction site. With the disposition of the blocking device according to the invention in the crosspiece of a cylinder lock, the common longitudinal axis is oriented approximately radially with respect to the rotational axis of the rotor. On the front portion of the blocking element a blocking pin is disposed and this blocking pin in the blocking position of the cylinder lock extends into an approximately radial bore on the rotor. Since in the proximity of the crosspiece between rotor and stator normally no mechanical tumblers are disposed, the radial bore in the rotor for the extension of the blocking pin on the blocking element can readily be disposed in this region. This can be done without mechanical tumblers needing to be omitted or their function needing to be restricted. The blocking device according to the invention is thus independent within in a broad range from the system of the mechanically coded mechanical tumblers, i.e. the blocking device according to the invention can be combined with different types of construction of cylinder locks. This is made possible since all cylinder locks correspond to an industry standard and have a crosspiece projecting radially from the stator outwardly, which serves among others for the torsion-tight fastening of the cylinder lock in the structural object, for example a lock box. 
     The advantages of the method for operating the blocking device according to the invention comprises that the rotational motions of the driven end of the shaft of the control means can be directly converted into linear motions of the blocking means in the direction of the longitudinal axis and that onto the blocking element during the displacement process from the blocking into the opening position, and conversely, as well as in the holding positions no additional holding and/or resetting forces are exerted. This has the further advantage that the motion sequence and the method for generating the motions of the blocking element on the part of the blocking device are relatively simple and nevertheless an intervention into the motion sequence by additional forces exerted without authorization from the outside becomes virtually impossible. In displacing the blocking element into the blocking position or into the opening position it is advantageous to stop the rotational motion of the driven end of the shaft with the aid of final stops on the helical drive unit when these end positions have been reached. The stopping or the standing still of the driven end of the shaft is electronically detected via the control device and after the passage of a predetermined control time, the energy supply to the control means is interrupted. This control method has the advantage that the control means which drives the helical drive unit via the driven end of the shaft does not need to be stopped with the aid of an electronic position control, but rather the position of the helical driving controls the interruption and/or the enabling of the energy supply to the control means. The control means is advantageously supplied with energy intermittently or pulsatingly during the activated time interval. Therewith, multiple utilization and optimization of the energy source, for example of a battery, is possible, especially if the entire length of the energy supply is determined by the control device. The activation of the control device, and thus the type and manner of the enabling of the energy supply to the control means with the driven end of the shaft is activated by information signals which are transmitted from a mobile information medium to the cylinder lock. The transmission of the information or data, can advantageously take place directly via contact elements or via a contact-free transmitter-receiver system. The mobile information medium can be, for example, a key with an electronic data medium or an identification card with a corresponding data medium. In the cylinder lock or in the associated lock box an electronic data processing unit is installed as a counterpiece, which exchanges the data with the mobile information medium via direct contacts or a contact-free transmitter-receiver system, for example a radio system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following the invention will be explained in further detail in conjunction with embodiment examples with reference to the attached drawings. Therein depict: 
     FIG. 1 a double cylinder lock with a partial section through the region with the additional blocking element, 
     FIG. 2 a section through an installation unit with control means, helical drive unit and additional blocking element in the blocking position, 
     FIG. 3 an installation unit according to FIG. 2 with the additional blocking element in the opening position, 
     FIG. 4 a detail representation of a first portion of the helical drive unit with the helical groove and the blocking element connected therewith, 
     FIG. 5 a cross section through the first portion of the helical drive unit along line  5 — 5  in FIG. 4, 
     FIG. 6 a devolution of a helical groove on a first portion of the helical drive unit in schematic representation, 
     FIG. 7 a devolution of a helical groove of a first portion of the helical drive unit in schematic representation with an end region with negative pitch, 
     FIG. 8 a second embodiment of an installation unit with an additional blocking element and a different implementation of the threaded drive, and 
     FIG. 9 a further embodiment of an installation unit with the additional blocking element and a further embodiment of the helical drive unit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 a cylinder lock  1  with a blocking device according to the invention is shown, with this being a double cylinder lock with two lock cylinders  23 ,  24 . These two lock cylinders  23 ,  24  are fixedly connected with one another via a crosspiece  3  in a manner known per se and disposed such that an interspace is formed between them in which, in a manner also known, an engagement piece  4  is disposed for actuating (not shown) locking elements. Each of the two locking cylinders  23 ,  24  of the cylinder lock  1  comprises a mechanically coded blocking system, which is developed for example according to Swiss Patent No. 407 799 and comprises a housing  11 , a stator  9  and a rotor  10  rotatable in this stator  9  by means of a key  2 . The depicted key  2  comprises at its key bit  6  as well as on the broad sides grooves  8  with codings for (not shown) tumblers, as well as also on the narrow sides for the so-called edge tumblers  7 . With a fitting key  2 , which has the correct codings on the broad sides and on the narrow sides of the key bit  6 , the blocking tumblers can be moved into the opening position and therewith the mechanical portion of the cylinder lock  1  can be unlatched. In spite of the great complexity of the mechanical codings  7 ,  8  on key  2  it is possible to copy these with suitable machine tools and without authorization to fabricate copies of the keys which make possible the unblocking of the mechanically coded portion of the cylinder lock  1 . In order to prevent the opening of the cylinder lock  1  with a key whose mechanical portion has been copied, the depicted cylinder lock  1  is provided with an additional electronic coding. For this purpose, into the bow  5  of key  2  an electronic structural element  25  is installed on which an electronic coding is stored. 
     This electronic module or electronic structural element  25  is connected with a conducting leader  26  which, when the key  2  is completely inserted into the cylinder lock  1 , cooperates with a transmission unit  27  on the cylinder lock  1 . In the depicted example the transmission unit  27  has available electric contacts  28  which are resiliently pressed onto the leader  26  and establish a conducting connection between the transmission unit  27  and the electronic structural element  25 . In this way data can be exchanged between the key  2  and the cylinder lock  1 . With corresponding implementation of the key  2 , or of the cylinder lock  1 , the data exchange can take place even without hard-wired contacts, for example by radio transmission. The transmission unit  27  is connected with an electronic control device  17 , with this connection not being depicted. This electronic control device  17  comprises a computer which, depending on the installed hardware and software, can detect whether or not the key  2  with the electronic structural element  25  inserted into the cylinder lock  1  is an original key or whether or not other conditions are met, such as for example opening authorization for the cylinder lock  1  in a certain time range. Connected with this electronic control device  17  is an additional blocking device which is independent of the mechanical coding of the lock-key combination and comprises an additional blocking element  13  which can engage and disengage the rotor  10 . The additional blocking element  13  is part of an installation unit  22 , which is installed in a bore  29  in crosspiece  3 . This installation unit  22  comprises a control means  14 , in the described example a micrometer with rotating driven end of the shaft  15 , a helical drive unit  16  and a linear guidance  20  for the additional blocking element  13 , as well as a housing  21 , which encompasses these components. The control means  14 , the driven end of the shaft  15 , the helical drive unit  16  and the additional blocking element  13 , or their longitudinal axes, are all on a common longitudinal axis  18 . This common longitudinal axis  18  is directed at approximately right angles with respect to the rotational axis  30  of rotor  10 . Via the electronic control device  17  the energy supply from a (not shown) energy source, to the micrometer or control means  14  is controlled. The rotary motions generated by micrometer or control means  14 , of the driven end of the shaft  15  are converted via the helical drive unit  16  into linear motions of the additional blocking element  13 . These linear motions of the additional blocking element  13  are directed on the common longitudinal axis  18  and in the extension of this axis  18  a radial bore  19  is disposed in rotor  10 , in or from which the blocking element  13  can engage or disengage. For this purpose on blocking element  13  is disposed a front portion in the form of a blocking pin  71 , which in the blocking position of the cylinder lock  1  extends into the bore  19  on rotor  10  and prevents therewith rotary motions of rotor  10  in stator  9 . And it does so even if the mechanical tumblers actuated by the mechanical codes on key  2  are in the opening position. The additional blocking element  13  can only be retracted from the blocking position in bore  19  on rotor  10  into the opening position if a corresponding control command from the electronic control device  17  enables the energy supply to the control means  14  such that the rotating part of the helical drive unit  16  rotates in the correct direction. The corresponding control commands of the electronic control  17  are only generated if from the electronic structural element  25  on key  2  the correct electronic coding can be read and simultaneously at the time of the opening attempt this key  2  is also authorized for opening. The electronic coding data in the electronic structural element  25  on key  2  are encrypted such that they cannot be copied. It is also not possible to bring the additional blocking element  13  through external interference from the outside, for example through magnetic forces, by vibrating, application of oscillations, impacts etc. out of the blocking position into an opening position. This is ensured through the implementation according to the invention of the helical drive unit  16  and the disposition according to the invention of the structural elements in the installation unit  22 , which forms the blocking unit. This very high security against actuation attempts of the additional blocking element  13  through external interference from the outside is attained, on the one hand, by the absence of holding or resetting forces acting additionally onto the blocking element  13 , and, on the other hand, through the forming according to the invention of the helical drive unit and the disposition of all actuation elements contiguously with the additional blocking element  13  on the common longitudinal axis  18 . The installation unit  22  with the additional blocking element  13  can be built highly compactly due to the forming according to the invention and the length can be reduced so far that installation into the crosspiece  3  of a cylinder lock  1  with normal structural dimensions is possible. The outside dimensions of the cylinder lock  1  are therefore of a size equal to a cylinder lock only mechanically coded with the exception that the length in the direction of the rotational axis  30  is greater in order to permit installation of the transmission unit  27 . This permits the installation of a cylinder lock with the blocking device according to the invention into lock boxes and other structural elements with the standardized cutouts for commercial cylinder locks. 
     FIGS. 2 and 3 show an installation unit  22  in enlarged representation and in longitudinal section, and in Figure the blocking element  13  is depicted in the blocking position and in FIG. 3 in the opening position. At the lower end of the control means, or micrometer  14 , electric leaders  31  are disposed which serve for the control and power supply and are connected with the electronic control device  17 . At the upper end of the control means  14  is located the driven end of the shaft  15  which can rotate about the longitudinal axis  18  in both directions of rotation. On the driven end of shaft  15  a coupling member  32  is fastened so as to be torsion-tight, with this coupling member  32  comprising at the upper end a longitudinal groove  33 , which forms an inner element of a slide groove joint. As a counter piece of this slide groove joint is disposed on the blocking element  13  a transverse bolt  34  which engages the groove  33  on the coupling member  32 . This transverse bolt  34  forms an outer element of the slide groove joint between the blocking element  13  and the driven end of the shaft  15  or the coupling member  32 . Through this slide groove joint  33 ,  34  the rotary motions of the driven end of the shaft  15 , or of the coupling member  32  are transmitted to the blocking element  13 . But simultaneously the blocking element  13  can become displaced in the direction of the longitudinal axis  18  linearly in the direction of arrow  35 . On blocking element  13  is disposed an end portion  36  which has a core bore  37 . Between this core bore  37  in end portion  36 , or in the blocking element  13  and the coupling member  32  a slide guidance is developed. On the outer shell  38  of the end portion  36  of blocking element  13  a helical groove  39  is disposed. This end portion  36  with the helical groove  39  forms a first portion of the helical drive  16 . From bottom to top this helical groove  39  is coiled with a positive pitch over 360° about the end portion  36  and comprises at the lower and upper end stop faces  40  and  41 , which terminate the helical groove  39 , as is shown in FIG. 4. A second portion of the helical drive unit  16  is formed by a slide element  43  in the form of a pin and a sleeve  42 , which is a part of the housing  21 . The slide element  43  is connected with the sleeve  42  and projects radially into the bore  44  of sleeve  42 . The portion projecting into the bore  44 , of the slide element  43  engages the groove  39  at the end portion  36  of the blocking element  13 . Sleeve  42  is a component of housing  21 , which encompasses the control means  14 , the helical drive unit  16  and a portion of the blocking element  13 . Housing  21 , as evident in FIG. 1, is fastened torsion-tight in the bore  29  on crosspiece  3  of the cylinder lock  1 . In the embodiment example depicted in FIGS. 2 and 3 of the installation unit  22  thus the control means  14  and its driven end of the shaft  15  and housing  21  with slide element  43  are stationary. If the end portion  36  of blocking element  13  is set into rotation via the driven end of the shaft  15  and the slide groove joint  33 ,  34 , the blocking element  13 , due to the relative motion between the slide element  43  and the helical groove  39 , is displaced linearly in the direction of arrow  35 . Thereby the blocking element  13  can be displaced in the direction of the longitudinal axis  18  linearly from the blocking position depicted in FIG. 2 into the opening position depicted in FIG.  3  and conversely. In the blocking position the blocking pin  71  on the front portion of blocking element  13  is driven out of housing  21 . In FIGS. 4,  5 , and  7  the forming according to the invention of the helical groove  39  is evident. One of the end regions  45 ,  46  of the helical groove  39  is assigned to the opening position or blocking position of blocking element  13 . At least on the end region  46  of helical groove  39 , which is assigned to the blocking position, an additional longitudinal element  47  of the groove is disposed which does not have a pitch. As is evident in FIG. 4, in the example shown, on end region  45  of helical groove  39  is also disposed an additional longitudinal element  48  without pitch. If the slide element  43  is in the blocking or opening position of blocking element  13  in one of the two longitudinal elements  47 ,  48  without pitch of the helical groove  39 , it is held form-fittingly and without additional holding or resetting forces. This relative position between slide element  43  and end portion  36  of blocking element  13  without actuation of the control means  14  can virtually not be changed. Attempts through external interference, such as vibrations and the like, to disengage or engage the blocking element  13  from or into the blocking or opening position, therefore fail completely. Thereby the security of the blocking device is substantially increased and it is virtually impossible to actuate the cylinder lock  1  without mechanically and electronically correctly coded key  2 . In order to avoid damaging the control means  14  the current and/or voltage variation is monitored through the electronic control device  17  and processed by a control program. If the slide element  43  abuts one of the two stop faces  40  or  41  of helical groove  39 , the thereby generated changes of current and/or voltage on the control means  14  are determined and after a certain length of time has passed, the energy supply is interrupted. But it is also possible to detect via the control program predetermined control times and to interrupt the energy supply to the control means  14  after the passage of the control time. The supply of energy to the control means  14  takes place intermittently. This leads to very simple solutions and limit switches or position controls, such as are required in other cases, can be completely avoided. The resting mass of control means  14  and of helical drive unit  16  as well as the motion deflection within helical drive unit  16  ensure a secure positioning of the slide element  43  in the two end regions  45  and  46  of helical groove  39  even with de-energized control means  14 . 
     FIG. 5 shows a cross section along line  5 — 5  through the end portion  36  in FIG.  4 . The slide groove connection between driven end of the shaft  15  and end portion  36  of the blocking element  13  are evident, with here a further embodiment being shown which differs from the embodiment according to FIGS. 2 and 3. On the driven end of the shaft  15  a coupling member  49  is fastened so as to be torsion tight, which comprises two keys  50  directed radially outwardly and offset by 180° with respect to one another. In the core bore  37  of end portion  36  or blocking part  13  are disposed four longitudinally directed keyways  51  each offset by 90° into which the keys  50  extend form-fittingly and slidingly. This implementation of the slide groove joint  50 ,  51  permits a simpler positioning of the blocking element  13  on the coupling member  32  or on the driven end of the shaft  15  during the assembly. If required, the slide groove joint can also be developed with a polygonal connection. 
     FIG. 6 shows a schematic representation of the formation of the helical groove  39  on the first portion  36  of the helical drive unit  16 . The depicted devolution corresponds to the configuration according to FIG.  4 . The helical groove  39  comprises a stroke region with a positive pitch  52  with end regions  45  and  46 . End region  45  is therein located on an upper position plane  53  and end region  46  on a lower position plane  54 . The stroke difference between these two position planes  53 ,  54  forms the stroke travel  57  and corresponds to the linear displacement travel of blocking element  13  from the blocking position into the opening position and conversely. The stroke range of the helical groove  39  according to this example extends over 360°, i.e. it corresponds to one convolution about end portion  36 . The additional longitudinal elements  47  and  48  which in the end regions  46  and  45  adjoin the stroke range, do not have a pitch and extend over a rotational range of 90°. 
     These two additional longitudinal elements  47  and  48  of helical groove  39  without pitch are each in a radial plane with respect to longitudinal axis  18 . 
     In FIG. 7 is shown an additional advantageous implementation of the helical groove  39  on at least one of end regions  45  or  46 . Especially on the end region  46  of the helical groove  39  the additional longitudinal element  47 ′ which does not have a pitch, is shortened and, instead, an additional longitudinal element  55  is added which has a negative pitch  56 . Through this additional change of direction in the proximity of the blocking position the security against unauthorized interference is additionally further increased. The additional longitudinal element  47 ′ without pitch can be shortened for example to a range of 30°, and the additional longitudinal element  55  with negative pitch  56  can extend, for example, over a range of 60°. 
     In FIG. 8 an installation unit  22  with a blocking element  13 ′ is depicted, which comprises a second embodiment of a helical drive unit  16 . On the driven end of the shaft  15  of control means  14  a slide element  58  in the form of a radial cam is fastened. On blocking element  13 ′ an end portion  59  with an inner bore  60  is disposed. Into the wall of this inner bore  60  again a helical groove  61  is worked, which, with respect to pitch and stroke range as well as end regions is implemented identically to those described in connection with FIGS. 4,  6  and  7 . Here also the end region  45  of helical groove  39  is associated to the opening position and end region  46  to the blocking position. The slide element  58 , which is connected with the driven end of the shaft  15 , extends into this helical groove  61  and is displaceable in it. On the outer shell of end portion  59  an anti-twist securement is disposed which comprises a longitudinal groove  62  in this outer shell and a guidance pin  63 , which is fastened on housing  21  and extends into groove  62 . The blocking element  13 ′ and the end portion  59  connected therewith is only linearly displaceable in the direction of longitudinal axis  18  and can not be twisted about the longitudinal axis  18 . Rotational motions of the driven end of the shaft  15  about the longitudinal axis  18  therefore effect through the relative motion between the slide element  58  and helical groove  61  linear motions of blocking element  13 ′ in the direction of the longitudinal axis  18  and thus the desired displacement of blocking pin  71  from the blocking position into the opening position and conversely. In this embodiment the end portion  59  which is fixedly connected with blocking element  13 ′, forms the first portion of helical drive unit  16 . The second portion of helical drive unit  16  is formed by slide element  58  on the driven end of the shaft  15 . The slide element  58  is movable relative to blocking element  13 ′. 
     The installation unit  22  depicted in FIG. 9 comprises a further embodiment of helical drive unit  16 . In this embodiment on the driven end of the shaft  15  a cylindrical structural part  64  is fastened so as to be torsion-tight. Into the outer shell surface of this cylindrical structural part  64  is worked the helical groove  65 . Form and implementation of this helical groove  65  correspond here also to the embodiment according to FIGS. 4,  6  and  7 . However, in this structural variant the end region  47  of helical groove  39  is assigned to the opening position and the end region  45  to the blocking position. On blocking element  13 ″ is again disposed an end portion  66  with an inner bore  67 . Into this inner bore  67  extends the cylindrical structural part  64  and between the outer shell of this cylindrical structural part  64  and the inner bore  67  a slide guidance is formed. On the end portion  66  furthermore a slide element  68  in the form of a guidance pin is disposed, with this slide element  68  radially projecting into inner bore  67  and extending into helical groove  65  on the cylindrical structural part  64 . Into the outer shell of end portion  66  again a longitudinal groove  69  is worked, into which extends a guidance pin  70  which is fastened on housing  21 . This prevents the blocking element  13 ″ or its end portion  66  to be twisted about longitudinal axis  18 , however it is possible to displace the blocking element  13 ″ linearly along this longitudinal axis  18 . Rotational motions of the driven end of the shaft  15  or of the cylindrical structural part  64  about the longitudinal axis  18  therefore effect via the slide element  68  and the helical groove  65  a linear displacement of blocking element  13 ″ in the direction of longitudinal axis  18 . Therewith, in turn, the linear displacement of blocking element  13 ″ or of blocking pin  71  from the blocking position into the opening position, and conversely, is possible. In this embodiment the cylindrical structural part  64  on the driven end of the shaft  15  forms the first portion of helical drive unit  16 . The second portion of helical drive unit  16  is formed by slide element  68  fastened on end portion  66 . The end portion  66 , and therewith the slide element  68 , is therein fixedly connected with blocking element  13 ″.