an apparatus according to the invention , particularly for machining the ends of bar material , consists in accordance with fig1 and 2 of a machining station 1 and a loading and unloading device 2 . the machining station 1 has a casing 3 , which is preferably closed on all sides . an operating status indicator 4 is mounted on the casing 3 . in addition , the casing 3 is supported by means of appropriate feet 5 on , for example , a workshop floor 6 . as shown in fig2 on one side of the casing 3 a tank 7 for an appropriate hydraulic supply for individual machining or holding devices is disposed , while on the other side an appropriate control desk 8 is connected by swivel arms 9 to the casing 3 . an interior space 10 of the casing 3 is accessible by opening a sliding door 11 . in the present example of embodiment a sliding door 11 is provided only on one side , but a similar door may also be situated on the other side . an appropriate lighting device 12 supplies adequate light in the interior space 10 . the sliding door 11 preferably has a window through which a working region of the interior space 10 is well visible . for the purpose of feeding bar material ( not shown in greater detail ) into the interior space 10 of the machining station 1 , an inlet channel 13 is provided which is directed towards the loading and unloading device 2 and ends in the interior space 10 near a vise 14 . the bar material is held by clamp jaws 15 in said vise 14 ( see fig3 ). in addition , the vise 14 is in the form of a centering vise , cooperating with a positioning pin 16 . this positioning pin 16 pushes the bar material into a desired end position before the clamp jaws 15 are closed . the positioning pin 16 is fastened on a cross slide 17 , which is adapted to travel in the x and y directions . the corresponding axial and transverse movements are made with the aid of a servomotor 18 and of recirculating cone [ sic ] screws ( not shown in greater detail ) connected to the servomotor 18 by means of appropriate gear units . the cross slide 17 is covered by an appropriate bellows 21 for protection against dirt , chips and cooling liquid . at the side of the positioning station , indicated in particular by the positioning pin 16 , a machining device 23 is provided on the cross slide 17 . in this machining device 23 a chuck 24 is driven by a servomotor 19 with the aid of a suitable gear unit 20 . said chuck 24 serves to hold an appropriate tool by which the ends of the bar material can be machined . in this connection facing , internal beveling , external beveling , hollowing , form drilling , corner rounding , external cylindrical turning , spotfacing , flat punching , crowning , form turning , whirling , face milling or drilling are envisaged . if two different machining operations should be desired at the end of the bar material , it is possible to provide an additional machining device on the other side of the positioning pin 16 . a sawing unit 26 is also associated with the vise 14 . in this arrangement a sawblade 27 crosses over the vise 14 and is driven by an electric motor 28 through a gear unit 29 . the sawing unit 26 is also connected to a lifting device 30 , for which an appropriate hydraulic cylinder 31 is used . by means of this lifting device 30 the sawing unit 26 can be raised and lowered in the direction z . this arrangement therefore allows vertical infeed , the forces during sawing acting almost vertically directly on the bar material . clean cuts with little chatter are thus achieved even with high - strength materials . in the figures it is not shown in greater detail that the respective end machining point receives a coolant . in addition , appropriate collecting channels for the coolant and for the chips produced during the machining are not shown , although according to the invention the chips and the coolant can be discharged to an appropriate tray 32 via the collecting channels . in fig3 it can also be seen that an appropriate hydraulic pump 33 is associated with the tank 7 . the loading and unloading station 2 has a sturdy machine frame 35 . the actual table 36 , which is vertically adjustable by means of four lifting members 37 disposed parallel to one another , is mounted on said machine frame 35 . only one of these lifting members 37 is shown in fig1 . the lifting members 37 are however connected by means of appropriate spindles 38 and gear units 39 to a handwheel 40 , with the aid of which height adjustment in the direction z1 of the table 36 is possible . the height adjustment is infinitely variable and can be read on a measuring device . the lifting members 37 support a rectangular frame 42 , which in the example of embodiment illustrated consists of appropriate hollow sections . said frame 42 holds storage arms 43 , directed towards the interior of the frame , and oppositely disposed unloading arms 44 . both the unloading arms 44 and the storage arms 43 are in addition also connected together by a supporting sectional member 45 , only one supporting sectional member 45 for the unloading arms 44 being shown in fig2 . in addition , at least the unloading arms 44 should be made adjustable in respect of their inclination , being provided , for example directly opposite the storage arms 43 , with a pivot point about which the unloading arms 44 can be conjointly turned . in addition , conveyor rollers 46 , which are fastened to the frame 42 by means of appropriate bearing blocks 47 , are provided between the frames 42 . for this purpose these bearing blocks 47 are mounted on appropriate cross struts or the like . each conveyor roller 46 has an axle 48 passing through at least one bearing block 47 . a drive wheel 49 is mounted at the other end of the axle 48 and is connected by means of a drive belt ( not shown in greater detail ) or the like to a drive 50 . said drive 50 is preferably in the form of an electric motor . an appropriate gear unit 51 is also provided . the drive wheels 49 may also be sprocket wheels driven by an appropriate chain . in this respect no limits should be imposed on the inventive principle . the conveyor rollers are preferably driven at two selectable speeds , and in addition the direction of rotation can be changed . moreover , extractor members 52 spaced apart from one another are disposed between individual conveyor rollers 46 . the extractor members 52 are mounted on support plates 53 which are connected together on both sides by means of a longitudinal frame 54 . this longitudinal frame 54 is acted on by hydraulic cylinders 55 , so that the extractor members 52 are slidable in the direction y1 . in addition , lifting cylinders 56 are associated with the extractor members 52 , and with their aid the extractor members 52 can be raised in the direction of the stored bar material . the lifting cylinders 56 or a corresponding piston rod 57 is pivotally connected to the frame 42 . the bar material laid on the storage arms 43 is pressed by means of ram cylinders 58 against a stop 59 and held in that position . for the purpose of holding down the bar material on the storage arms 43 , holding - down means 60 are disposed on both sides of the loading and unloading device 2 . said holding - down means consist for the sake of simplicity of a cross strip 62 which is fastened on a gallows 61 and which can be lowered downwards by means of hydraulic or pneumatic cylinders 63 . the loading and unloading device 2 is first aligned relative to the machining station 1 , that is to say the conveyor rollers 46 are brought into line with the inlet channel 13 . bar material , which may consist of round or polygonal sections and which is to be machined , is then laid on the storage arms 43 , and said bar material is pressed by means of the ram cylinders 58 against the stops 59 . with the exception of the first section or sections , the bar material is held down by the cross strips 62 to ensure that a certain order is achieved . the extractor members 52 are then moved in the direction y1 , to be specific by means of the hydraulic cylinders 55 . the extractor members 52 are thereupon raised by means of the lifting cylinders 56 , so that a first bar comes to lie in a first notch in the extractor member 52 . the extractor members 52 are then moved back in the direction y1 and lowered so that the bar lies in the conveyor rollers 46 . said conveyor rollers 46 are rotated , so that the bar is delivered into the inlet channel 13 until its end strikes against the positioning pin 16 . the position of the bar is corrected by moving the positioning pin 16 . if for example an end is then to be cut off straight , the sawing unit 26 is lowered . the vise 14 is opened again and the position of the bar is corrected with the aid of the positioning pin 16 and of the moving conveyor rollers 46 . the machining device 23 is thereupon moved in the direction y into the machining position and the end of the bar is machined , the depth of penetration of a tool into the end of the bar being for example determined by means of the cross slide 17 . as soon as the machining has been completed , the conveyor rollers 46 are rotated in the opposite direction , so that the bar is pulled out of the machining station 1 . appropriate limit switches ( not shown in greater detail ) indicate when the bar has reached its end position . the extractor members 52 are now raised , so that the bar which has already been machined is received in a second notch in the extractor member 52 . the dimensions of the extractor member 52 are such that at the same time the next bar to be machined can be taken from the storage arms 43 . on a further movement of the extractor members 52 in the direction y1 , the bar which has already been machined is brought above the unloading arms 44 and the bar which has still to be machined is brought over the conveyor rollers 46 . on the lowering of the extractor members 52 the bar which has already been machined is then laid on the unloading arms 44 and the bar which has still to be machined is laid on the conveyor rollers 46 . this operation is then continuously repeated . automatic feeding of the machining station 1 is thereby achieved . all the working operations are controlled from the control desk 8 for the machining station and also from another control desk for the loading and unloading device . in another example of embodiment of a machining station 1a , as shown in fig4 individual machining steps are carried out separately of one another , and in particular the machining of both ends of a bar 101 is possible . this bar 101 is introduced by means of driven driving rollers 102 into the machining station 1a , passing through under the sawblade 27 of the sawing unit 26 and also being guided through the vise 14 . in this example of embodiment another vise 103 is provided opposite the vise 14 , the jaws 104 of said vise 103 being adapted to hold and clamp the bar 101 . the vise is followed by an indexing unit 105 , which is adapted to travel in the direction x . for this purpose the indexing unit 105 is mounted on guide rods 106 . with the aid of the indexing unit 105 the length of a bar portion is determined , and this length is then separated from the bar 101 by means of the sawing unit 26 . after a bar portion 107 has been cut off , it is taken up by grippers 108 , which have an appropriate gripper mouth 109 . at the other end of the gripper mouth 109 the grippers 108 are connected fixedly in terms of rotation with a shaft 110 , the latter being mounted in two bearings 111 . a shaft drive ( not shown in greater detail ) can turn the shaft 110 so that the grippers 108 are pivoted in the direction of the double arrows 112 . after the clamp jaws 104 or 15 have been opened , the bar portion 107 is thereby pivoted out of its first machining position and brought into a second machining position , as also indicated in fig4 . in this second machining position the bar portion 107 is held by two vises 113 and 114 spaced apart from one another and adapted to travel on guide columns 115 . the operation can once again be carried out in the direction x . the bar portion 107 is fastened in such a manner that both its ends project out of the respective vise 113 , 114 and can be machined . this machining is achieved with the aid of a machining device 23a and of a second machining device 23b . for the sake of simplicity each machining device 23a , 23b is likewise mounted on the guide columns 115 beyond the respective vise 113 , 114 , an appropriate slide table 116 likewise being adapted to travel in the direction x . guide rails 117 serving to guide a cross table 118 are disposed on the slide table 116 . the cross slide 17 is moved with the aid of a driven spindle 119 , which passes through an internally threaded sleeve ( not shown in greater detail ) on the underside of the cross table 118 , so that the latter is adapted to travel in the direction indicated by the double arrow y . the spindle 119 is driven by means of a motor 120 and a drive belt 121 . in the example of embodiment shown in fig4 two servomotors 19a and 19b can be seen on each cross slide 17 , these servomotors driving clamp jaws 24 for tools 122 by means of appropriate gear units 20a and 20b . with the aid of these tools the bar portion 107 can be machined simultaneously at both ends . it is obvious that it is also possible for a plurality of such servomotors together with a plurality of corresponding driven tools also to be provided on a cross slide 17 . in addition , it is also envisaged to dispose a plurality of vises 113 and 114 respectively side by side , each of them holding a bar portion , this plurality of bar portions lying side by side then being simultaneously correspondingly machined by the tools 122 . in this respect no limits should be set on the building block principle of the present invention . in this way the machining of separate bar portions , or else of a plurality of bar portions , can be carried out simultaneously . in one practical example of embodiment a total of 16 nc axes were provided . in connection with control it must be pointed out that each motor and drive is freely programmable . this means very considerable flexibility for the machining of bar ends . any wish expressed by customers can be met . in an example of embodiment not illustrated in greater detail the cross slide also carries a machining unit driving a tool which is movable in the lifting direction z . this machining unit then crosses over the corresponding bar portion . for example , transverse bores can thus be formed in the bar portion . in this selected form of construction of a machining device la it would be advisable only in very rare cases for machined bar portions 107 to be taken up again by the grippers 108 and to be guided back by means of the driver rollers 102 to the loading and unloading station , although this possibility is also to be included in the principle of the present invention . however , for the continuous machining of the bar portions 107 , further grippers 123 are associated with the vises 113 and 114 , these grippers being of similar construction to the grippers 108 . a pressure medium cylinder 124 is shown for each of these grippers 123 to enable the gripper mouth 109 to be operated . the gripper 123 is mounted and driven in the same way as the grippers 108 , for which reason no further description will be given , while the same reference numerals are used for like elements . after the grippers 123 have been pivoted outwards , the machined bar portion 107 is then deposited on a stand ( not shown in greater detail ). fig5 and 6 illustrate another example of embodiment of a loading and unloading device 2a . associated with this loading and unloading device 2a , according to fig5 and 6 , is also a bar magazine 130 , which serves in particular to separate individual bars and to convey bars of different diameters . rocker arms 133 , which are slidable in the direction of the double arrow 132 , are situated on a main frame 131 , which can be seen in particular in fig6 and which will not be described in further detail . each rocker arm 133 consists of a u - shaped frame part 134 comprising a base strip 135 , a support leg 136 and an obliquely inclined slide - up leg 137 . this u - shaped frame part 134 serves to receive bars ( not shown in greater detail ). a conveyor strip 138 , which can be obliquely inclined as desired , ensures that bars situated in the frame part 134 can always roll to a conveying corner 139 . this conveyor strip 138 is therefore pivotally connected to the slide - up leg 137 by means of a pivot pin 114 , while at the other end it can be adjusted by means of an appropriate socket pin 141 passing through a slot 142 in the conveyor strip 138 and through various bores 143 in the support leg 136 . the rocker arms 133 are mounted astride guide plates 144 and 145 , and the latter are mounted on cross bearers 146 of the main frame 131 . at the same time they are mounted in slots ( not shown in greater detail ) for sliding in the direction of the double arrow 132 between said guide plates 144 and 145 . the sliding of the rocker arms 133 in the direction of the double arrow 132 is brought about by three rams 147 , which by means of miter gear unit 148 and corresponding connection rods 149 are connected to one another or to a handwheel 150 . the miter gear unit 148 is so designed that the rams 147 are movable in the direction of the double arrow 132 , thereby moving a longitudinal beam 151 . the rocker arms 133 are fastened to said longitudinal beam 151 by means of a mounting plate 152 . the rams 147 may also be in the form of threaded spindles , which then pass through corresponding threaded sleeves 153 . a lifting device 155 is associated with the slide - up legs 137 and serves to lift out a bundle of bars , while a corresponding lifting cylinder 156 is connected to a lifting beam 157 extending in the longitudinal direction . lifting strips 158 project upwards from said lifting beam 157 between individual rocker arms 133 and extend approximately parallel to a slide - up surface 159 on the slide - up leg 137 . by means of this lifting strip 58 [ sic ], or of an end edge 160 of the latter , bars lying in the conveying corner 139 are conveyed along the slide - up surface 159 until they roll over an edge 161 of the slide - up leg 137 and roll to a stop projection 162 . from this position near the stop projection 162 the bars are lifted out by means of a lever 163 which is pivoted on a stationary rod 164 and turns about the latter . it turns in the direction of the double arrow 165 . this turning is effected with the aid of a pressure cylinder 166 whose piston rod 167 is pivotably connected to the lever 163 at the end remote from the rod 164 . in order that only two pressure cylinders 166 will be needed , the individual levers , which also engage between the rocker arms 133 , are joined together by means of a longitudinal shaft 168 . in addition , the bars are prevented from slipping off a slide surface 169 on the lever 163 by means of an edge prong 170 . it can be seen clearly from fig6 that the distance a between the stop projection 162 and the edge prong 170 varies to the same extent as the distance b between the slide - up surface 159 and an outer edge 151 of the lifting strip 158 . the variation of both the distance a and the distance b is brought about by the sliding of the rocker arm 133 in the direction of the double arrow 132 . it can by this means be determined how many bars are taken out of the magazine by the lifting strip . furthermore , bars may be taken out in accordance with predetermined bar diameters . for this purpose the distance c between the machine frame 35 and the main frame 131 remains the same . the pressure cylinder 166 is in addition situated on the machine frame 35 . after the levers 163 have taken one or more bars from the slide - up leg 137 , these bars roll along the slide surface 169 after a determined rotation of the lever 163 , and are transferred direct to the storage arms 43 . the storage arms 43 also have here a stop prong 172 which is roughly disposed in such a manner that a bar is situated directly above the conveyor rollers 46 . through the lowering of the storage arms 43a on rotation about a pivot pin 173 the bar is laid on the conveyor rollers 46 . if bar portions are to be brought back and laid on unloading arms 44 , this is achieved with the aid of the extractor members 52 , which also turn about their pivot pins 174 . it is obvious that the pivot pins 173 all the storage arms 43 and the pivot pin 174 all the extractor members 52 [ sic ] are connected together and can also be operated conjointly .