Patent Publication Number: US-2004045413-A1

Title: Device for screwing in fastening elements

Description:
[0001] The invention relates to an apparatus of the kind defined in the preamble of patent claim 1.  
       [0002] In such an apparatus for setting fastening elements made of plastic holders and screws, it is indeed always possible to utilize equally long screws for bridging the widest possible region of different thicknesses of insulating material in attaching covering strips or plates. However, the length of the tubular extension of the plastic holder then varies accordingly. Given these different lengths of tubular extensions of the plastic holders, there also arises the need for different insertion techniques in order to enable the proper setting of the fastening elements. In the tubular extensions of various lengths the screw heads are inserted more or less deeply in these tubular extensions so that a drive shaft having a spike extending into the tubular extension has to be lowered different distances beyond the lower end of a wheelable base frame in order to be able to carry out complete driving in of the screw.  
       [0003] From (German Patent Publication) DE 200 07 656 U1, there is known an apparatus of the kind mentioned at the outset, in which the two tubular portions are slidable inside each other, specifically at most as far as permitted by a slot. By means of a height adjusting device, through choice of an appropriate hole for the insertion of a turnable screw, it can be predetermined how far one of the tube portions can be introduced vertically into the other tube portion during the screwing process. This depends on the length of a plastic holder to be attached. During the screwing in process the tubular portions are telescopically slidable inside each other. A boring machine used as screwdriver starts in each screwing in process at the same height. Only the path which the one tubular portion traverses, until an adjustment ring bears against the other stationary tube portion is adjustable. In the known apparatus, the height adjusting device is, essentially only a bottom abutment. This bottom abutment determines how far the one tubular portion can be moved downward by the drive shaft of the screwing device. By means of the height adjusting device one cannot determine how far the drive shaft projects from the screwing device at the bottom. But this is undesirable for tubular extensions of different lengths because these cannot be retained by the spike during the screwing in process. Therefore the plastic holder must be brought into the set position by external guiding devices.  
       [0004] Apparatuses of the initially described kind are known especially in connection with a wheelable base frame European Patent EP 0 600 285 A1. Normally the supply of the plastic holders takes place via a magazine. The plastic holders with screws which are normally already inserted are presented in a screwing in position co-oriented with the screwing in axis and are there grasped by the screwing device. By pushing down on the screwing device there then takes place the screwing in of the entire fastening element through penetration of the inserted screw into the substructure. However, it is always necessary to prevent turning of the plastic holder relative to the screwing device because it must be inserted in a precisely oriented position into the part to be screwed in, i.e. it must not turn together with the screwing device. For this purpose, there are normally provided relatively long guide shafts or guide tracks in order to protect the plastic holder from turning until the final setting of the fastening element. There can also be provided height adjustable, spring loaded pivotable jaws, which move in height along with the setting process and which remain applied until ultimate setting. Because of these measures, there are required especially costly structural means which also make it especially difficult to remove from the guide shaft or the guide tracks a plastic holder which for some reason becomes tilted.  
       [0005] Using a setting apparatus known from (European Patent Publication) EP 0 535 547 B1, fastening elements can not be screwed in which have a large area washer with a tubular extension made of plastic. The fastening elements for which the known setting apparatus is provided have a washer or a load distributor made of metal. This setting apparatus also does not have a holder for the fastening element which consists of a spike extending into a tubular extension of a plastic holder and located at the free end of the drive shaft. Instead, in this setting apparatus, there is provided a by-pass projection which acts to maintain the load distribution disk in place at a contact point of the load distributing disk next to a ramp. Thus, in this case, the holding device simultaneously serves to prevent turning.  
       [0006] The present invention has the object of providing a structurally simple and operationally problem-free adjustment device for fitting tubular extensions of various lengths on the plastic holders and providing an optimum holding arrangement and turning prevention for the plastic holders.  
       [0007] This object is achieved by an apparatus with the characteristics recited in patent claim 1.  
       [0008] By means of the inventive measures it is very simple to achieve that the spike which is to be introduced into the tubular extension, and which is also connected to the screwdriver via an appropriate drive shaft, can penetrate appropriately deeply into the tubular extension. Thus, through the mutual displacement of the tubular portions which extend coaxially within each other, compensation is achieved simply for tubular extensions of different lengths on the plastic holders.  
       [0009] To do so, there is provided in structurally simple manner at the outer tubular portion, a structurally simple spring loaded adjustable bolt, which extends into a radial hole in the inner tubular portion. This not only enables simple adjustment, but also secure locking and especially self-latching locking which remains securely in this locked condition until it is manually reopened.  
       [0010] In addition, it is proposed that the radial holes on the inner tubular portion follow each other with regular axial spacing. This makes possible a step-by-step adjustment, matching the regular dimensions of the tubular extensions of the plastic holders.  
       [0011] It is regarded as an especially desirable measure to provide the outer tubular portion with a bottom abutment which works together with a base frame. By these means the advancing movement of the plastic holder is always so adjusted that the large area washer of the plastic holder comes to bear directly on the surface of a strip to be attached. This creates the situation that, despite the simple adjustability for tubular extensions of different lengths, there is no need to simultaneously adjust the bottom abutment. Therefore the bottom abutment is always effective as a function of the ultimate setting of the plastic holder, whereas simple mutual displacement of the two coaxial tubular portions enables bridging of that dimension by which the screw head penetrates more or less far into a tubular extension of greater or lesser length.  
       [0012] Structurally simple provision is made for holding the spring loaded adjustable bolt in the bottom abutment. There is present here a corresponding accumulation of material so that sufficient guiding and resulting holding of the inserted spring loaded adjustable bolt becomes possible.  
       [0013] It is also advantageous to form the bottom abutment as a collar surrounding the outer tubular portion which receives the spring loaded adjustable bolt on one side and which has an abutment projection on the opposite side. Here, too, a functionally and structurally very simple solution can be provided whereby the adjustment can be carried out optimally and furthermore an appropriately stable abutment projection can be provided.  
       [0014] Optimum turning prevention can be achieved by providing the bolt which prevents the turning of the plastic holder at a projecting abutment surface on the free end of the screwing device and at the edge of the large area washer of the plastic holder serving as a turning preventing abutment.  
       [0015] By means of the spike which extends into the plastic holder there becomes possible precise axial orientation as known from (German Patent Publication) DE 197 54 356 A1, so that there is always assurance that the plastic holder and therefore also the screw inserted in the plastic holder, i.e. the complete fastening element, is oriented precisely along the screwing in axis. By means of the one or more bolts provided on the screwing device in accordance with the invention, precise orientation of the plastic holder about the screwing axis is further ensured in structurally simple fashion, which also makes it possible for this precise orientation to remain in effect until the ultimate setting of the fastening element. The turning prevention for the large area washer of the plastic holder therefore remains in effect until the ultimate setting of the fastening element.  
       [0016] By very simple but highly effective construction, the guide shafts or guide tracks heretofore required in such apparatus can be omitted along the entire displacement path of the screwing device. It is also not necessary to hold the large area washer of the plastic holder in place until ultimate setting using spring loaded jaws which can be swung out of the way or which can be pushed out of the way against spring loading, which also led to an expensive and space consuming structure. Simply by providing one or more freely projecting bolts, sufficient ability is provided for creating restraints against turning of the plastic holder.  
       [0017] This structure is equally effective whether the apparatus as a whole is used as a hand tool or is placed in a wheelable base frame. When used as a hand tool, the plastic holder is also oriented precisely coaxially with the spike and around the spike and is prevented from turning by the bolts functioning as restraints. Thus the same desirable results are achieved when applied to a hand tool as also when part of a wheelable base frame.  
       [0018] Overall, the inventive apparatus is substantially improved from the structural view point, it is simple to operate and makes possible especially good accessibility to all important parts. Even if there should occur irregularities in the supply of the fastening elements and especially of the plastic holders, manual intervention can be made without any problem because no interfering guides, shafts or enclosures are needed.  
       [0019] It is further proposed that the one or more bolts be located at a terminal edge of the abutment surface so that the one or more bolts prevent turning of an introduced plastic holder only at a longitudinal limit of the plastic holder. Therefore it is necessary to provide only turning prevention, and there is no need to provide suitable abutments or abutment areas at opposite longitudinal limits of the plastic holders, and much less such annularly closed devices. Indeed one such bolt would suffice but, by using at least two bolts, it can be ensured that the plastic holder can turn about the screwing axis neither in one nor in the opposite direction.  
       [0020] It is further proposed to make the length of the freely projecting bolts approximately equal to the thickness of the large area washer of the plastic holders in the corresponding abutment region. Because the plastic holder is supported on the free end of the abutting surface of the screwing device, a short bolt suffices to provide effective turning prevention for the plastic holder. Therefore, only a short length of these bolts is needed in order provide an abutment at the corresponding place, i.e. in the corresponding abutment region of the longitudinal limit of the washer.  
       [0021] Thus the apparatus according the invention is advantageously useable both as a hand tool and also as part of a wheelable base frame. In this regard it is advantageous if an apparatus is installed in a base frame and supplied with individual fastening elements with plastic holders, which are kept ready in a holder with appropriate orientation, wherein spring loaded jaws which can be swung out of the way are provided as lower support.  
       [0022] Specifically, when the device is used in a wheelable base frame, it becomes possible to preposition the fastening elements in appropriate orientation so that, during pushing down of the screwing device, the spike connected to the drive shaft penetrates into the plastic holder until the plastic holder comes to rest on the abutment surface at the free end of the screwing device. Because the plastic holders are kept ready in the holder with the appropriate orientation these plastic holders can be grasped at their longitudinal limit by the freely projecting bolts, at which time the screwing device itself takes over the function of preventing turning. During further downward movement of the screwing device, the spring loaded jaws are swung out of the way downwardly so that the plastic holder and the screwing device can pass further downward through this holding arrangement, up to the ultimate screwing in and setting of the fastening element. Thus, the holder serves mainly for the orderly keeping ready of the fastening elements because thereafter no additional guide rail or additional guide shaft is needed.  
       [0023] If, in an apparatus according to the invention, there is to be provided a simple way to securely hold the fastening element consisting of plastic holder and screw in the axial direction until the ultimate screwing in but, in so doing, enabling relative rotation between spike and plastic holder without creating frictional heat harmful to the plastic holder, then a device is proposed in which the spike has a body with a threaded bolt for attachment to the free end of a drive shaft, and in which there is applied to the body and the threaded bolt a tubular part for joint attachment to the body at the free end of the drive shaft, the restraining means taking the form of at least one protruding projection, which creates an axially secure hold, in cooperation with at least one annular, inwardly projecting bulge inside the tubular extension of a plastic holder.  
       [0024] This object is achieved by an apparatus with the characterizing features of patent claim 1.  
       [0025] By simply introducing the spike through pushing down on the screwing device or by applying a plastic holder to the screwing device, there can be achieved secure axial positioning of the plastic holder relative to the screwing device and this can be accomplished without applying significant force. Even if the annular inwardly projecting bulge formed in the plastic holder, which can also be present in multiples is annularly closed, easy insertion is required because only partial regions of the circumference of the spike need to pass beyond this bulge or bulges. Therefore, there is no need to provide an annularly closed widening of the tubular extension of the plastic holder in the region of the bead or beads, but there suffices, for example, a short one-sided bulge, because only the corresponding projection needs to be guided across the bead or beads.  
       [0026] In this regard, the (European Patent Publication) EP 0 783 063 A1 shows a cylindrical portion of a screwdriver. A screwing tip is inserted in the cylindrical portion. Annular ribs are provided in the plastic holder of a fastening element which is to be set, which are in clamping engagement with the cylindrical portion of the screwdriver. Thus the cylindrical portion of the screwdriver also serves for axial retention, but provided that the cylindrical portion of the screwdriver and the plastic holder rotate in unison. Otherwise undesired frictional heat would be created between the two.  
       [0027] This known apparatus is unsuitable for screwing in fastening elements when the plastic holder should not turn during screwing in, because the washer should maintain a predetermined orientation around the screwing axis until the ultimate setting of the fastening element.  
       [0028] In apparatus according to (German Patent Publication) DE 93 11 122 U1, the above-mentioned problems do not arise because this is intended for fastening elements which are hammered in.  
       [0029] In order to obtain orderly securing of the plastic holder to the spike and therefore to the screwing device, it is only necessary to keep the plastic holder from getting lost because, in the direction of removal of the plastic holder from the screwing device itself, there are no forces acting in this direction which could arise during setting or screwing in.  
       [0030] Frictional heating can not occur in use of the device according to the invention, because it provides no friction-creating attachment between plastic holder and spike, but rather a positive retention which readily permits mutual relative rotation.  
       [0031] A further special advantage of the apparatus according to the invention is that its spike can be attached to any screwing apparatus, in order to make this able to set fastening elements of the kind under discussion herein.  
       [0032] In this connection it is also especially advantageous if two diametrically opposite projecting protrusions are formed on the spike. Then, upon inserting the spike into the tubular extension of the plastic holder, the tubular extension in this region is deformed into an elliptical shape, whereas, after complete insertion of the protrusions, the tubular projection again returns to its original shape.  
       [0033] The insertion and orderly retention are improved even further by providing the projecting protrusions with an inlet ramp which extends at an acute angle to the screwing in axis, followed by an abutment which falls steeply away. This substantially facilitates the insertion process, even when inserting the plastic holder by hand and yet provides sufficient security against axially sliding displacement of the plastic holder. 
     
    
    
     [0034] Exemplary embodiments of the invention are described further in the description which follows with reference to the drawings. There are shown in:  
     [0035]FIG. 1 a side view, partially in cross-section, of an apparatus for screwing in fastening elements pre-stored in a magazine;  
     [0036]FIG. 2 a side view of a portion of the apparatus of FIG. 1 viewed in the direction of arrow II;  
     [0037]FIG. 3 a cross-section through a screwing apparatus not mounted on a base frame;  
     [0038]FIG. 4 a view of a fastening element insertable in the apparatus, and consisting of a plastic holder and a screw;  
     [0039]FIG. 5 a cross-section through a retaining means for keeping a fastening element in readiness;  
     [0040]FIG. 6 a top view of the retaining means according to FIG. 4;  
     [0041]FIG. 7 an enlarged view of the portion VII in FIG. 1, shown partially in section, with fastening element inserted and held ready;  
     [0042]FIG. 8 a side view of the screwing device in the direction of arrow  8  in FIG. 7 shown partially in section;  
     [0043]FIG. 9 the fastening element in side elevation, shown partially in section, wherein a spike connected to a drive shaft is inserted in the plastic holder;  
     [0044]FIG. 10 an enlarged representation of a partial segment of the spike in cross-section;  
     [0045]FIG. 11 a view of this partial segment from below. 
    
    
     [0046] In an apparatus  1  for screwing in fastening elements  2  kept ready in a magazine there exists a base frame  4  movable by means of wheels  3 , in which there is retained a screwing device  6  with integrated screwdriver  5  displaceable in the vertical direction. The entire screwing device  6  is set in a mount  7  and therefore adapted to be handled by an operator via hand grips  8 . The mount  7  is slidably retained via appropriate guide rails, the whole screwing device  6  being repeatedly self-propelled into the upper rest position by means of a gas actuated spring.  
     [0047] The fastening elements  2  are brought into the screwing in position via supply elements  10 .  
     [0048] By pushing the screwing device  6  downward, a spike  12  provided with an attachment  49  for a screw  11  extends into the opening of a plastic holder  13  of the fastening element  2  far enough for the attachment  49  to grasp the screw head. Appropriate bolts  14  prevent the plastic holder  13  from turning during the pushing down of the fastening element  2  and during the screwing in process itself.  
     [0049] As can be seen from FIG. 4, by means of the apparatus  1  there are set the fastening elements  2 , which consist of the plastic holder  13  and the preassembled screw  11 .  
     [0050] Of course it would also be possible to supply the screw  11  only after the plastic holder  13  rests singly in the screwing in position. However, especially for such fastening elements made of plastic holder  13  and screw, it is advantageous and also appropriate for rapid setting, if the screw is already preassembled in the plastic holder and can also be supplied in this form via an available magazine  15 . Between the magazine  15  and supply elements  10  which guide the plastic holder  13  toward the screwing in position, there is provided a single-unit picking apparatus  16 , which assures that, during each setting process, i.e. by each pushing down of the screwing apparatus  6 , one fastening element  2  is freed up and brought into the screwing in position. The single-unit picking apparatus  16  has a lever  17  which is swingable about an axis  19  that extends transversely to the supply direction from the magazine  15 .  
     [0051] The screwing device  6 , which also encompasses a pass-through drive shaft  64  provided at its free end with spike  12  having the attachment  49  and with restraining means  53  for holding back the plastic holder  13  in the axial direction, is specifically configured. The screwing device  6  consists of two tubular portions  58  and  59  which extend coaxially within each other, and corresponding mounting rails  65  and  66 . The dimension of the mutually inserted parts of the two tubular portions  58  and  59  is adjustable, with the tubular portions  58 ,  59  also being mutually lockable in the selected arrangement. On the outer tubular portion  58 , a spring loaded adjustable bolt  61  is provided. This bolt  61  extends into a radial hole  60  on the inner tubular portion  59 . The inner tubular portion  59  is provided with several radial holes  60  which follow each other with a regular axial spacing so that it becomes possible to provide locking between the outer tubular portion  58  and the inner portion  59  at corresponding spacings. By sliding the two tubular portions  58  and  59  more or less far within each other, it follows that the spike  12  of drive shaft  64  extends more or less far beyond a lower bearing surface  52  of the screwing device  6  so that it becomes possible to match the various lengths of the tubular extensions  25  of plastic holders  13 . It is as a function of the length of these tubular extensions  25  that spike  12  must be able to extend more or less deeply into the tubular extension  25  so as to reach the required setting depth with appropriate penetration into the head of screw  11 .  
     [0052] Due to assembly considerations and also for stiffening of the screwing device  6 , mounting rails  65  and  66  are provided at at least two opposite regions of the outer tube portion  58 , which are firmly connected via screws  67  with the outer tube portion  58 . Recessed in mounting rail  65  and screwed into the outer tube portion  58  there is further provided a screw  68  which engages a longitudinal slot  69  in the inner tube portion  59 . This assures that the tubular portions  58 ,  59  cannot be completely pulled out of each other and furthermore mutual turning prevention is provided thereby.  
     [0053] On the outer tube portion  58  there is provided an abutment  62  which is used in conjunction with a base frame  4 . Preferably, the spring loaded adjustable bolt  61  is held in this abutment  62 . In the specific embodiment illustrated, the abutment  62  is configured as a strap surrounding the outer tube portion  58 , which receives the spring loaded adjustable bolt  61  on one side and has a bearing projection  63 ′ on the opposite side. Thus, upon pushing down the apparatus  1 , the abutment  62  and the abutment projection  63 ′ is also moved downwardly together with the screwing device  6  until it comes into contact with an abutment screw  63 . Further advance of the screwing device  6  is then precluded. To carry out a fine adjustment of the bottom abutment, the abutment screw  63  can be turned farther outward or else from an intermediate position farther inward or outward so as to respectively create the optimum pressure by the large area washer of plastic holder  13  against a strip to be attached.  
     [0054] For the orderly retention of the fastening element  2  which is to be set by the apparatus  1  there is provided a retention device  51  which consists on the one hand of spike  12  formed at the free end of a drive shaft  64  and on the other hand of bolts  14 . For precise co-orientation with the screwing in axis, spike  12  extends into the interior of the tubular extension  25  of plastic holder  13 . There, spike  12  can grasp the head of screw  11  via the attachment  49 . To prevent turning of the inserted plastic holder  13  there are provided, in the illustrated exemplary embodiment, two bolts  14  freely projecting from an abutment surface  52  formed at the free end of the screwing device  6 . These bolts  14  operate as turning prevention abutment at the edge of a large area washer  24  of plastic holder  13 . Two bolts  14  are provided in order to prevent turning of the washer  24  in both directions of rotation.  
     [0055] It is readily possible to provide only a single such bolt  14  or to provide a longitudinal abutment in place of a bolt. All that is required is to prevent turning of plastic holder  13 , by means of abutments extending axially beyond the abutment surface  52  or by forming a single abutment. Of course, this can also be done in conjunction with a specific configuration of the peripheral shape of the large area washer  24  of plastic holder  13 . For example, such bolts or other abutments can be matched to specific contours in the peripheral region of the washer or in relation to openings at the edge of or inside the washer. It is also possible-to provide at the opposite sides appropriate bolts  14  or similar abutments for the large area washer but for orderly retention it suffices to carry out such measures on one side only. In this connection it would also be possible to provide on abutment surface  52  of screwing device  6  a recess matching the shape of large area washer  24  which can receive the entire washer  24  or at least a part of it, so as to provide turning prevention in this manner. Thus it can be seen that there is possible not only the most effective and simplest construction, but that measures can also be taken which are structurally more complicated.  
     [0056] The length of the freely projecting bolts  14 , or other corresponding abutment structures corresponds approximately to the thickness of the large area washer  24  of plastic holders  13  in the corresponding abutment region. Thus, there needs to be assurance that at least the edge of the large area washer  24  can be properly grasped by the bolts  14  at a longitudinal limit.  
     [0057] Especially in connection with the placement of apparatus  1  in a wheelable base frame  4 , it is also desirable to prepare the fastening elements consisting of plastic holder  13  and premounted screw  11  appropriately for the screwing in process. For that purpose, a holding means  70  is provided on the base frame  4  which has an input region  71  which becomes narrower from the top toward the bottom. To this input region  71  there is connected an opening  72  which matches the contour of the large area washer  24 . This opening  72  is closed off toward the bottom at two oppositely situated edge regions by jaws  73 ,  74 . These jaws  73 ,  74  are provided with springs  75 ,  76  so that these jaws  73 ,  74  are shown in the closed position illustrated in FIG. 4, in their rest position beneath opening  72 . As soon as a plastic holder  13  is introduced into the holding means  70 , the screwing device  6  can be pushed downward. When the spike  12  then penetrates into the tubular extension  25  of the plastic holder  13  and the bolts  14  have grasped a lengthwise limit of large area washer  24 , the entire screwing device  6  is pushed further downward so that the jaws  73 ,  74  can swing away downwardly against the force of springs  75 ,  76 . From then on, the plastic holder  13  and with it the entire fastening element  2  is held exclusively by the screwing device  6  so that no additional guide shafts or guide tracks are needed. After return of the screwing device  6  following the end of the screwing in process the jaws  73 ,  74  are swung back into their initial position by the springs  75 ,  76  so that the holding means  70  is again ready to receive the next fastening element  2 .  
     [0058] By means of the embodiment shown in FIGS.  9  to  11  there is now essentially achieved the axial retention of the fastening element  2 , and especially of the plastic holder  13  until the ultimate setting of the fastening element  2 . In so doing, it makes sense to not impede the screwing in process for the screw  11  through the axial retention of the plastic holder  13 , or possibly to detract from the necessary turning-protected retention of the plastic holder  13 . Further to be achieved is that the plastic holder  13  can be applied to the spike  12  simply and without great force exertion, i.e. optionally also by hand, in order to move into an axially secured position on this spike  12 . Thus, when the plastic holder  13  is in position applied to the spike  12 , no significant friction will be created upon mutual rotation.  
     [0059] The plastic holders  13  which are to be used here have, spaced from the large area washer  24  in the region of the tubular extension  25 , a circumferentially closed bead  77  which, in the area of the tubular extension  25 , creates, so to speak, a narrowed space. This bead  77 , which also serves to prevent loss during premounting of the screws  11 , namely when the head  50  of the screw can no longer be moved backwards across this bead  77 , in the present case it is used for axial retention of the plastic holder  13  on spike  12 . On spike  12 , or on a separate detachable portion  78  of spike  12 , there are present hold-back means  53  which form a sort of retainer arrangement  51  for retaining the plastic holder  13  in the direction of the screwing in axis. To this end, the hold-back means  53  take the form of at least one projecting protrusion  79 , which provides assured axial retention in cooperation with the bead  77  which is formed inside the tubular extension  25  and which extends annularly inward.  
     [0060] Preferably spike  12  or portion  78  has two diametrically opposed projecting protrusions  79 . To make it easier to slide the spike  12  and therefore the portion  78  into the interior of the tubular extension  25 , the projecting protrusions  79  have an inlet ramp  80  extending at an acute angle to the screwing in axis and an abutment  81  which falls away steeply behind it. Thus, easy introduction is possible and with it easy reshaping of the tubular extension  25 , whose cross-section is reshaped into a kind of ellipse during penetration by portion  78 . As soon as the two mutually opposite protrusions  79  then leave the vicinity of bead  77 , the tubular extension  25  again reverts to its original circular cross-sectional shape so that the bead  77  can engage portion  78  behind abutment  81 . As soon as the protrusions  79  have passed over this bead  77 , rotation of spike  12  in tubular extension  25  can again take place without appreciable impediment. Therefore, no particular effort is needed to produce rotation of plastic holder  13 . Rather, there suffices the use of the two bolts  14  or corresponding other abutments, at the bottom abutment surface of the screwing device  6 .  
     [0061] It is also readily possible to construct these protrusions  79  in another way. For example there could be provided such protrusions  79  respectively displaced by 90° from each other. It is also possible to extend these protrusions  79  respectively over predetermined circumferential portions, or to provide a circumferentially closed, protrusion-like strap. However, the introducing is then less easy to accomplish. In any case it is necessary to provide appropriate protrusions or a protrusion-like strap, in order to accomplish the engagement of a corresponding bead  77 . If indeed only a cylinder-shaped part were used to frictionally engage the tubular extension  25  even if it had one or more beads  77 , then there would always occur a correspondingly large friction between spike  12  and the interior of tubular extension  25 , which is to be avoided in this situation.  
     [0062] From FIG. 11 it can also be seen that the upper segment of portion  78  forms a kind of hexagonal head. This provides in simple manner the possibility of screwing portion  78  onto the free end of drive shaft  64 , thereby attaching to the drive shaft  64  the body  84  which bears the connection  49  and has a threaded bolt  83 .  
     [0063] In FIGS. 5 and 6 it can be seen how the fastening element  2  and particularly the plastic holder  13  is kept ready when using the apparatus  1  in a wheelable base frame  4 . A receptacle  7 , 0  is attached to the base frame  4 , which has a narrowing input region  71  and an opening  72  connected thereto which matches the circumferential contour of the large area washer  24  of plastic holder  13 . To close the bottom of this opening  72 , jaws  73  and  74  are provided which are held in this position by springs  75  and  76 . When, by pushing down the screwing device  6 , the spike  12  has penetrated into the interior of the tubular extension  25  of plastic holder  13 , and has there gone past the bead  76 , there promptly ensues appropriate axial retention of the fastening element  2 , with two bolts  14  being elliptical at a longitudinal limit of the large area washer  24 . Upon further pushing down the two jaws  73  and  74  are pushed downwardly against the force of springs  75  and  76 , whereupon the fastening element  2  is held only by the axial retention between spike  12  and tubular extension  25  and the radial retention by abutment at bolts  14 .  
     [0064] The measures used in accordance with the invention for the axially secure retention of a plastic holder can be used in an apparatus which is utilized as a hand tool or else in an arrangement in which the apparatus is part of a wheelable base frame. Likewise such a structural embodiment can be used for supplying plastic holders, i.e. in a kind of magazine. In that case, each time that a fastening element is made ready, the spike used exclusively for magazine operation would have to be pulled out again. However, it would also be possible to utilize such a spike for withdrawing a fastening element from magazine storage, in which case the fastening elements would have to be guided all the way to spike  12 , or the spike  12  itself would have to be pivoted from a withdrawal position into a screwing in position.