DE1621874C3 - Method and device for producing self-locking screws by applying a patch of thermoplastic material to an axially limited part of the thread surface - Google Patents

Description

The present invention relates to a method and apparatus for manufacturing self-locking screws by applying a stain made of thermoplastic material to one axially limited part of the thread surface and a device for performing this method.

Self-locking screws are already known which are provided with plastic inserts. to For this purpose, the screws are provided with bores or grooves in which plastic inserts are then inserted can be used. It turns out, however, that due to the provision of grooves or Bores within the screws, the strength of the same is reduced in an undesirable manner. Furthermore, relatively tight manufacturing tolerances must be adhered to so that the plastic inserts do not can fall out in an undesired way. This in turn has the consequence that such self-locking Screws are relatively expensive so that they can only be used for special applications.

There are also self-locking screws known in which small plastic balls under Heat and pressure are exerted on certain areas of the thread surface of screws. It has been found, however, that with such self-locking screws under heat and Plastic beads pressed on by pressure do not reliably adhere to the thread surface, so that when you unscrew the various nuts on the threads of each screw unwanted loosening of the pressed-on plastic parts comes about, whereby the self-locking Effect of the screws is lost.

In view of this prior art, it is therefore an object of the present invention to provide a To provide a method of manufacturing self-locking screws which is mass-produced Allowed such self-locking screws, it is ensured to a satisfactory extent that a unwanted loosening of the plastic parts applied to certain areas of the thread surface does not come about even if the nut is screwed on and loosened several times.

According to the invention this is achieved in that the plastic material is in the form of a constantly flowing Powder flow with a cross-section corresponding to the size of the spot is applied from a supply source, furthermore that the thread provided screws are automatically taken from a disordered supply with regard to their axes

aligned, fed to a conveyor track, to a temperature above the melting point of the plastic material heated, and one after the other with axes lying transversely to the powder flow along the conveyor track be moved through the powder flow, wherein 5 only the axially limited part of the thread surface in Comes into contact with the powder stream, and that then the screws without exerting a Forming pressure on the adhering stain to below the solidification temperature of the plastic material be cooled down.

In this context it is already known (see DT-AS 11 18 660), glue on along one To spray the workpieces transported by the conveyor, so that a velor coating is then carried out can be. Furthermore, it is known (see US-PS 24 28 284), certain with the help of nozzles To spray liquids onto an insulating wire that is moving past the nozzles to make a mark to do the same. Furthermore, it is known (see US-PS 32 12 915) of a dispensing device Conducting beads on a reciprocating heated bottle in order to create a coating to achieve the same. Finally, it is known (see DT-AS 11 34 129) to spray paint jets by means of spray nozzles to straighten insulated conductors in order to make an identification of the insulated conductors in this way be able.

In the context of the method according to the invention, a powder flow is transported along a conveyor track Screws directed, with the powder flow solely and exclusively in certain areas of the thread surface recorded. The screws conveyed along the conveyor are already on one above the Melting temperature of the plastic material lying temperature has been heated so that a certain Amount of powder flow on the respective limited areas of the thread surface to be melted got. When the screws cool down, the result is very good fixation of the thermoplastic existing stain, so that even after repeated screwing and loosening a nut detachment of the thermoplastic material patch from the thread surface does not come about. Since the individual steps of the method according to the invention are continuous can be carried out, this process is particularly suitable for the mass production of self-locking screws. This in turn has the consequence that such self-locking screws are relatively can be manufactured cheaply, so that there is a very wide range of possible applications.

In order to achieve that the stains made of thermoplastic material on the in Screws produced by the masses are each designed to be the same, it proves to be expedient if the cross-sectional shape of the powder flow can be precisely controlled. In this context it turns out furthermore it is expedient if the screws are moved through the flow of powder in a precisely fixed position will.

As the thread area in which a self-locking mechanism is opposite to screwed-on nuts, depending on Application can be different, it proves to be useful if the relative position of the Screws against the powder flow is adjustable.

In order to ensure that the powder flow is supplied to the limited areas of the thread surface with as little problems as possible to achieve, it also proves to be advantageous if the screws with horizontally lying Longitudinal axes are moved through the powder flow, while the powder flow is free from above is formed to fall down.

In order to ensure the best possible adhesion of the applied stains made of thermoplastic material reach, it also proves to be useful if before passing the screws through the Powder stream applied a primer to the axially limited part of the thread surface will.

A device for carrying out the method according to the invention is expediently of this type designed that a dispensing device is provided from which the powder flow can be dispensed, further that in the Area of the powder flow a conveyor, which the screws with crosswise to the path and to the powder flow aligned longitudinal axes promotes, and that a heating device is provided in the area of the conveyor, with which the screws are heated to a desired temperature before the powder flow is reached.

In order to achieve that the individual screws are fed as evenly as possible, it turns out to be as advantageous if the conveyor is provided with holding elements which hold the screws on the conveyor fix in position.

In order to finally be able to generate a powder flow that is as uniform as possible, it seems advantageous to when the dispensing device has a funnel with a vertically lying axis, which is equipped with a vibrator is coupled.

To determine the size and geometric shape of the thermoplastic patches applied to the screws To be able to influence plastic material in the desired way, it proves to be advantageous if a plate provided with an opening can be fastened at the lower end of the funnel, the Opening is dimensioned according to the desired cross-sectional shape of the powder flow.

In order to achieve that the intended vibrator can be made relatively small, it turns out as advantageous if a further funnel is arranged above the funnel, the vertical axis of which is offset from the vertical axis of the lower funnel.

In order to be able to heat the individual screws to as uniform a temperature as possible, it turns out to be Finally, it is advantageous if the heating device is an induction heater arranged along the conveyor is.

The invention will now be explained in more detail with reference to the accompanying drawings. It shows

F i g. 1 is a perspective view of a preferred embodiment of a device according to the invention,

F i g. 2 and 3 a plan view and side view of a self-locking screw with a plastic stain, by the device of FIG. 1 has been produced,

4 shows a cross section through the screw of F i g. 2 and 3 on line 4-4 of FIG. 2,

F i g. 5 is a partial view of the device of FIG. 1 on line 5-5 of FIG. 1, but with some parts for Explanatory purposes are cut open,

F i g. 6 is a fragmentary view in section taken along line 6-6 of FIG. 5,

F i g. 7 is a partially sectioned partial view

the line 7-7 of FIG. 6,

F i g. Figure 8 is a fragmentary plan view as seen from line 8-8 of Figure 8. 5 off,

9 is an enlarged partial cross-sectional view taken along line 9-9 of FIG. 8th,

FIG. 10 is an enlarged partial cross-sectional view taken along line 10-10 of FIG. 8th,

F i g. 11 is a further enlarged partial cross-sectional view on line 11-11 of FIG. 8th,

Fig. 12 is an enlarged partial vertical sectional view taken along line 12-12 of Fig. 8;

Fig. 13 is a partial sectional view taken on line 13-13 of Fig. 12;

F i g. 14 is a partial view taken on line 14-14 of FIG. 5 off,

F i g. 15 is an enlarged partial horizontal section on line 15-15 of FIG. 14,

F i g. 16 is an enlarged partial horizontal section on the Line 16-16 of FIG. 14,

F i g. FIG. 17 is a partial top plan view in section as seen from line 17-17 of FIG. 1 off,

F i g. Figure 18 is a partial view as seen from line 18-18 of Figure 17;

19 is an enlarged partial view seen from FIG Line 18-18 of Fig. 17,

F i g. FIG. 20 is an enlarged fragmentary view taken on line 20-20 of FIG. 17 off,

F i g. 21 and 22 are enlarged partial views of a single part of the device of FIG. 19, wherein however, certain parts take up different working positions,

F i g. 23 is an enlarged partial view of the device from FIG. 19, in which the assignment of the individual Parts are better explained to each other,

Figure 23A is a view of a single portion of the apparatus of Figure 19, but with a particular one Part takes up a different work position,

F i g. Figure 24 is a fragmentary view in section taken along line 24-24 of Figure 19;

F i g. Figure 25 is a partial horizontal section, on a reduced scale, taken on line 25-25 of Figure 25. 24,

F i g. Figure 26 is an enlarged fragmentary top plan view, partially cut away, of a portion of the apparatus of Figure 26. 25, which explains the work of a certain mechanism better,

FIG. 27 is a partial view, sectioned in places in the vertical direction, on the line 27 ^ 27 of FIG. 25,

Fig. 28 is an enlarged partial vertical section on the Line 28-28 of FIG. 25,

F i g. 29 is an enlarged partial vertical section taken on line 29-29 of FIG.

F i g. 30 is an enlarged partial vertical section taken on line 30-30 of FIG. 17,

Fig. 31 is an enlarged, partially cut away Partial plan view as seen from line 31-31 of FIG. 18 off,

F i g. 32 is an enlarged fragmentary view, partially in section, taken along line 32-32 of FIG. 30,

F i g. 33 is an enlarged partial view of a portion of the device of FIG. 30, showing individual features are better to see

F i g. 34 is a partial bottom view taken on line 34-34 of FIG. 33,

F i g. 35 is a fragmentary view, in partial vertical section, taken along line 35-35 of FIG. 18

F i g. 36 is a partial view taken on line 36-36 of FIG. 35 off,

F i g. 37 is a partial view similar to FIG. 36, although certain parts have a different working position take in,

Fig. 38 is an enlarged partial vertical section on the Line 38-38 of Figure 1,

F i g. 39 (on sheet of FIGS. 24, 25 and 26) is a partial plan view of a number of successive ones Screw mounts in a modified form,

F i g. 40 (on the sheet of FIG. 24, 25 and 26) is a partial view of the series of mounts of FIG. 39

Fig. 41 is a partial view modified by a series of screw mounts of a second Shape shows

F i g. 42 is a fragmentary view as seen from line 42-42 of FIG. 41, but with some parts for Explanatory purposes are omitted,

F i g. 43 is a partial view similar to FIG. 37, which, however, merely describes the object as a process of the modified screw mount of FIG. 42 and 43 explained

Figure 44 is an exploded view of a screw mount of the type such as that shown in FIG in Fig. 41 and 43 is shown, and

Fig. 45 is an enlarged horizontal section on the Line 45-45 of FIG. 43.

According to Fig.2 to 4 has a self-locking screw 55 with a plastic stain or a Similar item includes a metal body 56, preferably made of a magnetic material and the one shaft provided with a standard thread 58 and one enlarged head part 60 having. A patch 62 of thermoplastic material is with the thread surface through multiple threads of the thread 58 connected. The spot 62 covers a certain area of the thread surface and is spaced from the start end of the screw by at least one thread is equivalent to; it also extends a certain angle in the arc around the screw thread, for example less than 180 ° C, and gradually goes into the thread surface of the at the boundary edges 66 and 68 Thread 58 over.

According to FIG. 1, a preferred embodiment of the device according to the invention has a feed device 70 for screws or other objects that has a funnel 72 and the objects, such as z. Screws 55, in an arbitrary arrangement from the funnel 72 to an object alignment device -feeding device 74 feeds the aligned screws 55 one after the other to an object collection- or storage device 76 and misaligned screws to a collection or Ejector 77 leads. The article collection or storage facility 76 releases the screws one after the other to a main conveyor 78 which first passes the screws one after the other under an object heating device 80 and then the heated articles below a powder dispenser 82 and finally below an article dispenser 84 (Figs. 35 and 37) which removes the screws 55 from the main conveyor and puts them into a chute 86 (Fig. 1) from where they drop into a receptacle or quench tank 88.

The plastic powder dispenser 82 delivers a freely falling plastic powder flow through which the heated articles are passed through by the main conveyor 78, and excess Powder, d. H. that which has not been deposited on the screws is in the powder

collecting device 90 (Fig. 30 and 33) collected.

Article feeder

The article feeder 70 is best shown in FIGS. 1 and 5 to 7 can be seen. She owns suitable Carriers 92 and 94 on which the funnel 72 is attached. The funnel 72 has a receptacle 98 to its underside has an article dispensing opening 100, the size of the opening 100 by a adjustable slide 102 is changeable, which is slidable on the front wall 104 of the funnel 72 is attached. A vibrator 106 of conventional design is attached to the transducer 98 to vibrate it move, thereby facilitating a rapid drainage of the screws from the funnel 72.

The article feeder 70 also has a continuous flexible belt 110 that runs on rollers 112 and 114, the belt 110 being driven by the roller 114 in the direction of the arrow 116 (FIG. 7) and the upper flight of the belt is supported by a support plate 118.

The rollers 112 and 114 are mounted on suitable shafts 120 and 122 extending lengthways from them extending plates 124 and 126 are carried, which on holders * such. B. 128, are mounted on a base plate 130, which in turn is fastened to a carrier 94.

The roller 114 is attached to a shaft 122, at one end of which a roller 132 is attached which is rotated by a belt 134 which in turn is driven by a roller 136 which is mounted on the shaft of an electric motor 138 which is mounted on the base plate 130.

The article feeder 70 also has wall portions 140 that extend along the belt 110 extend on opposite sides of the same to hold the items on the belt, when fed from hopper 72 to alignment device 74. The side wall portions extend Also down at the front end of the strap 110 to lock the screws into the alignment device 74 to steer. The side wall portions 140 may be in any convenient manner, such as. B. by holder 142 to the Plates 124 and 126 be attached.

It should be noted that the article feeder 70 including the hopper 72 the Screws in a random order in rapid succession to the alignment device 74.

Alignment device for the objects

The item alignment device 74 is best shown in FIGS. 1.5 and 8 to 13 can be seen. It has a guide trough formed by inclined side plates 144 and 146 which are spaced at their lower ends to create a slot 148 sized to receive the shafts of the screws but prevent the larger heads of the screws from opening go through the slot. The side plates 144 and 146 are attached to the upper ends of two pairs of V-blocks 150, for example with bolts 152. The V-blocks 150 are adjustably held by blocks 154, which are fastened by means of bolts ⁶ S 158 on a support plate 156th Bolts 160 screwed into V-blocks 150 are secured in elongated slots 162, 163 and 164 in blocks 154 and support plate 156 so that V-blocks 150 can be moved together or apart.

The support plate 156 is in part attached to a support plate 165 via a leaf spring 166, which in turn is again attached to a suitable support frame 167. The plate 156 is also with at its front end connected to a vibrator 168, which in turn is attached to the support plate 165 again. The vibrator 168 facilitates the movement of the screws from the article feeder caused by the gravity 70 through the trough to the article collection and storage facility 76.

The side walls 144 and 146 of the alignment trough are provided with a plurality of strips 170, whose Edges to the trough side walls are relatively strongly beveled. The bars themselves are hers Upper edge inclined to its lower edge in the direction of the moving screws. The ledges serve this is done by the forward movement of the screws as they move along the trough due to the force of gravity move, change. In connection with the vibration of the trough side walls, they separate the screws from each other and make it easier for the shafts of the screws to fall into the slot 148.

A pair of screw guides 172 and 174 are, for example with bolts 176, on which are attached to the outside extending flanges 180 and 182 of the trough side walls 144 and 146 at the front end of the trough attached. The rails 172 and 174 form a guide trough extending from the alignment trough to the Collection or storage device 76 extend forward and downward.

Since the rails 172 and 174 are attached to the side walls 144 and 146, the rails 172 are and 174 are thus adjustable and can be moved towards and away from each other to create space to change between them as required to adapt to screws with different shank diameters is. The vibrator 168 also serves to cause the rails 174 and 176 to vibrate and thereby the movement of the screws along the channel caused by the heavy weight - for Support collection facility.

The unaligned article collector 77 has a hopper 184 which is shown in FIG in any convenient manner, such as By bolts 186 at the front end of plate 156 is attached. The funnel 184 is connected by a flexible tube 188 to a receptacle 190, from where the articles are sent by a worker to the hopper 72 of the article feeder 70 can be traced back.

The rails 172 and 174 extend across the open end of the funnel 184 and are with downward and outwardly sloping surfaces 192 and 194, as best shown in FIG. 11 can be seen so that the misaligned objects can slide down into the hopper 184.

It should be noted that the inner surfaces of the trough sidewalls 144 and 146 are attached their lower ends merge into the upper surfaces 196 and 198 of the rails 172 and 174, so that none Interfering with the free movement of the aligned screws from the trough and along the rails 172 and 174 takes place.

The rails 172 and 174 are supported at their forward end by a suitable block 200 shown in FIG

connected to the front upright wall of the funnel 184 in any suitable manner is. A gate 202 is attached to the forward end of the funnel 184 for catching misaligned screws thereon prevent moving along the rails beyond the funnel. This gate 202 can consist of a plate 204 which extend over rails 172 and 174 and over the top surfaces of the Rails have a recess so that the heads 60 of the aligned screws passing over the funnel walk through it. The gate can be fastened vertically adjustable in any way not shown, on brackets 206 attached to the front end of rails 172 and 174.

Item collection or storage facility

The article collection or storage facility 76 is best shown in FIGS. 1,5, 8,12,14 to 16,19 to see 25. It preferably has a vertically extending guide 208 which the Bolts are fed through a curved guide 210 extending from guide 208 to the front end of the channel which is formed by the rails 172 and 174 extends. The Leadership 208 has a rail 212 and rails 214 and 216, which are adjustable with bolts 218 and 220 on the rail 212 are attached. The bolts 218 and 220 pass through elongated openings in the rail 212, so that an adjustment of the rails 214 and 216 against each other and from each other is possible to screw them with Adapt shafts of different diameters.

As best shown in FIG. 16, the rails 214 and 216 face one another Protrusions 222 and 224, which are spaced from the surface of the rail 212 by a sufficient distance, so that the heads of the screws can pass through, and are laterally separated from each other so far that the The shafts of the screws can easily pass between the rails 214 and 216, and sideways from one another so are widely separated so that the shafts of the screws can easily pass between the rails 214 and 216, but without the screws tilting downwards or tilting sideways.

The guide 210 has a rail 226 similar to the rail 212, but which is curved so that it can extends from the top of the rail 212 to a location vertically above the rails 172 and 174 of the alignment device 74 is located. The rail 226 is at the top at an approximately vertical one Rail 228 attached, which in turn is attached to a bracket 230 attached to block 200. the Rail 226 is at the lower end, for example by one or more plates 232 and suitable bolts 234 attached to the upper end of the rail 212 of the guide 210.

The guide 210 has, in addition to the rail 226 curved rails 236 and 238, the rails 214 and 216 of the vertical guide are shaped similarly, thereby opposing projections 240 similar to the projections 222 and 224 formed ⁶ ^ the shafts between them are the Pick up screws with their heads resting on the inner surfaces of protrusions 240. It is to be noted that the inner surfaces of the projections 240 of the guide rails 236 and 238 constricting of the gegenüberlie- ⁶ S surface of the rail 236 have a sufficient distance so that a free movement of the screw along the rails 236 and is guaranteed 238, wherein however, the screws are prevented from significantly tilting or tilting with respect to the rail. It should also be noted that at the upper ends of the rails 226, 236, and 238, the opposing surfaces of the rails are shaped to create a "bell mouth" that allows the screws to move slightly from the rails 172 and 174 of the alignment device 74 into the Guide 210 allows, and that cam surfaces are formed which cause a movement of the screws on the guide rails of the guide 210 in the counterclockwise direction, so that the screws assume the correct position for the movement down the guide 210.

The vertical guide 208 is attached to an upright rail 244 with brackets 242, which is in turn attached at its lower end to an elongated hollow frame 246 which forms part of the Main conveyor 78 forms. The rails 214 and 216 have recesses at 214a and 216a (Figs. 20 and 24) to accommodate adjustable plates 248 and 250, which are vertically adjustable on rails 214 and 216 are fastened, for example by means of bolts 252 which pass through the vertical holes 254 in each of the Plates 248 and 250 pass through and screw into rails 214 and 216.

The rail 212 extends down over the plates 248 and 250 and has on the inner surface, for example fastened by bolts 256, an end block 258 for supporting the lowermost screw in the vertical guide, whereby the entire row of screws is supported in the vertical guide because the heads of the screws in this guide are in contact with one another. The rail 216 and the plate 250 terminate slightly above the top of end block 258 so that the screws can be removed from the side 55 is possible. However, the rail 214 and plate 248 terminate such a distance above the End blocks 258 so that the lowermost screw is not underneath plate 248 from the vertical guide can escape.

A feed control plate 260 is pivotable on a post 262 carried by the plate 250 (Fig. 19) and provided with a laterally extending extension 264, the inner edge of which is in alignment with the inner edge of the shaft guide projection 266 of the rail 250.

The projection 266 cooperates with a similar projection 268 of the plate 248, so that a Guide slot is formed for the shafts of the screws as they slide down the plates 248 and 250. the Extension 264 is dimensioned in the vertical direction such that normally the shaft of the lowest Screw can pass through the vertical guide when moving sideways, but through the Shank of a laterally moving screw not properly positioned on end block 258 is touched.

The control plate 260 is moved to a normal inner position by a spring 270. The spring 270 is attached at one end to a fixed pin 272 attached to plate 250 and at the other end to attached to a pin 274 carried by the plate 260. The pin 272 also serves as a stop for the plate 260 to allow inward movement of the plate under the action of the spring 270 restrict.

The mounting rail 244 for the vertical

Guide 208 is sufficiently flexible that the guide can be vibrated by a vibrator 276 attached to the guide rail 212 in any convenient manner. It is well known that the vibration of the vertical guide facilitates the downward movement of the screws along the guide.

It has been found to facilitate the transition of the screws from the vertical guide 208 to the main conveyor 78 (FIG. 1), a certain number of screws or a certain screw weight is desired in the vertical guide, and in particular it has been found that it is desirable the height of the screws in the vertical guide above a certain minimum and below one to keep a certain maximum. For this purpose the motor 138 is the article feeder preferably a two-speed motor, and the article collection or storage device 76 is equipped with an altitude sensing motor control which causes the motor 138 to operate with a higher speed works when the height of the screws in the vertical guide reaches a minimum value, and at a lower speed works when the number of screws in the vertical guide reaches a maximum height.

The motor controller has a pair of electrical eye units 278 and 280. The electrical Eye unit 278 has a photoelectric or photosensitive element (not shown) in one Housing 282 ^ which is attached to an arm of a U-shaped bracket 284, and a lamp or a another light source (not shown) located in a housing 286 attached to the other arm of the U-shaped bracket 284 is attached. The eye electric unit 280 similarly has a photoelectric element (not shown) located in a housing 288 which is supported on an arm a U-shaped bracket 290 is attached, and a lamp or other light source (not shown), the is in a housing 292 which is attached to the other arm of the bracket 290. The mounts 284 and 290 can be mounted in any convenient manner on a vertical arm 294, the in turn supported by a bracket 295 which is connected to a suitable part (not shown) of the fixture frame is connected so that the vibration of the vertical guide 208 under the action of the Vibrator 206 does not cause vibration of the eye electric units.

The electric eye units are mounted to produce beams of light which extend at a fairly sharp vertical angle over the path of movement of the shafts of the screws as the screws slide down the vertical guide. The control circuitry (not shown) by which the photosensitive element of the electric eye unit 278 causes the two-speed motor to rotate rapidly when light hits the photosensitive element of the unit and to rotate slowly when the light hits the photosensitive element of the electric eye unit 280 , is interrupted for more than a brief moment, can be of any suitable and well-known type.

It should be noted that each of the electrical Eye units is aligned so that the axis of the light beam is sharply inclined to the vertical to the To keep generation of false pulses low, which occur due to the distances between the shafts of the screws can whose heads lie against each other in the guide.

. Main sponsor

The main conveyor 78 is best shown in FIGS. 1, 17, 19 and 21 to 37 can be seen. It has a plurality of article holders 296 which are arranged in series on a flexible belt 298, which has a plurality of transverse elevations 300 which are distributed over the length of the belt, so that the belt without slipping through a toothed roller or a plurality of toothed drive wheels 302 can be driven which are fastened on a shaft 304 which are mounted in suitable bearings which are fastened on longitudinal projections of the box frame 264 (FIG. 1).

The wheel 302 may have end plates or flanges 306 which receive the belt 298 therebetween so that lateral displacement of the belt with respect to the drive wheel is prevented. The drive shaft 304 may be provided at one end with a bevel gear 305 which meshes with a bevel gear 308 on a countershaft 310 which is driven by a motor 312 via a non-slipping drive belt 314 and rollers 316.

The box frame 246 of the main conveyor 78 can be supported in any suitable manner, such as z. B. by holder 318 on a base plate 320 of a suitable frame (not shown). The upper flight of belt 298 rests on a suitable plate 322 having side flanges 324 extending upward is provided to allow a lateral displacement of the belt during movement on the plate 322 impede. The belt 298 runs at the end opposite the drive roller 302 over a Idler roller or an idler roller 326. Tension rollers 328 and 330, which are spaced from one another, are suitably adjustably mounted on the box frame 246 so that they conform to the inner surface of the touch the lower alignment of the belt 298. The rollers 328 and 330 are arranged so that the portion of the belt lies between them in a horizontal plane, as shown in FIG. 18 can be seen.

Each of the article holders 296 has a permanent magnetic plate 332 which is sandwiched between plates 334 and 336 of magnetic material, such as. B. steel, are arranged. Plates 334 and 336 are located between magnetic plate 332 and opposing non-magnetic end plates 338 and 340 which are provided with lower, outwardly facing flanges 342 and 344 through which the brackets can be secured to band 298, such as bolts 346 .

The magnetic plates 334 and 336 extend over the permanent magnetic plate 332, and the non-magnetic plates 338 and 340 extend across plates 334 and 336 and 340 has a couple of V-slots 350 and 352 at the top. The V-slots extend below the Upper edge of the magnetic plates 334 and 336 so that the screws received in the notches held magnetically by plates 334 and 336. Plates 332, 334, 336, 338 and 340 can held together by a rivet 354, preferably made of a non-magnetic material exist.

The opposite vertical sides of each

permanent magnetic plates 332 have opposite polarity, as shown in Fig.26 is. In order to improve the holding power of the brackets, the permanent magnetic plates are used 332 of adjacent brackets arranged or oriented so that the south pole surface of the plate 332 of the first bracket is on the same side as the north pole surface of plate 332 of the neighboring Bracket, as explained in Fig. 26. Through this Arrangement results in an even number of holders 296 on the belt 298.

The brackets are secured by the tape 298 successively below the vertical guide 208 of the collection or storage device 76, the V-notches of the brackets pointing upwards so that the shaft of the screw, which is located at the bottom of the vertical guide, is in a notch that lines up with the upright guide and the top edges of the magnetic plates 334 and 336 touched.

The plates 334 and 336 hold each screw firmly in place so that the axis of the screw turns into a horizontal plane extends when the brackets remove the screws from the vertical guide move away.

It should be noted that, as shown in FIG it is shown that the rails 214, 216, 248 and 250 of the perpendicular guide are slightly inclined to the vertical, so that the central line of the channel formed by these rails and thus the axes of the screws lie in the guide in a plane extending from the vertical plane through the apex of a screw receiving notch 350 or 352, which is directly in alignment with and below the gutter, angularly deviates, preferably by an angle in the range between approximately 2 and approximately 5 °. This Inclination of the gutter rails provides a smooth free movement of the screws from the vertical guide in and with the continuously moving brackets.

Article positioning and adjusting devices 356 and 358 are, as best shown in FIGS. 25 to 28 is to be seen, provided in order to precisely align the lateral position of the screws in the brackets 296. Such a device has a rotatable wheel 360 mounted on a vertical shaft 362 extending through a rail 364 is carried, which is movable for horizontal adjustment, for example by a bolt 366 in a slot 368, attached to a plate 370, allowing vertical movement adjustable, for example by bolts 372 in slots 374, attached to a rail 376, which in known Way (not shown) is connected to the box frame 246. A tape hold down device 378 is connected to the controller 356 to ensure that the head of each screw cleanly touches the surface of the wheel 360 as the screw passes the wheel.

The hold-down device 378 may have a wheel 380 which is arranged such that it the Surface of the belt 298 touches just below the wheel 360, with the wheel 380 on a horizontal Shaft 382 is attached, which is attached to a vertical rail 384, which in turn for a vertical Movement adjustable, for example by bolts 386 and slots 388, on which mounting rail 376 is attached.

It should be noted that when the wheel 360 touches the heads of the screws, it rotates moves the screws in each direction towards the belt so that the head of each screw is attached to the non-magnetic plates 340 of the screw holders. The screw positioner 358 may have an adjustably attached abutment rail 390, the path of the movement of the screws is inclined so that the starting end 64 of each screw is contacted and the screw in the transverse direction to the mounts is subjected to repositioning, so that said ends of the Screws are positioned at an even predetermined distance from the brackets.

The rail 390 can be attached to a mounting plate 394, for example by screws 392, which is adjustably fastened to a base plate 400, for example by bolts 396 in slots 398, so that it can be moved to and from the brackets. The plate 400 is attached by a bolt 402 a vertical rail 404 that is bolted to the box frame 264.

The tape hold-down devices 406 are connected to the position adjusting device 358, and these devices may include a pair of inverted L-shaped rails 408 attached to the belt support and -guide plate 322 are screwed on and extend over the edges of the same to make the surface of the tape 298 hold.

Object heating device

The article heater 80, as best seen in Figures 1, 17, 18, 29 and 31, has an elongated radio frequency induction heating coil 410 with spaced rods 412 and 414, between which the shafts of the screws pass when the conveyor is on the brackets the heating device 80 (see FIG. 29).

The length of the helix and the vertical spacing of the helical rods 412 and 414 are determined by the size of the Screws and the material from which they are made and determined by the speed of the conveyor, so that each screw is sufficiently heated by the time it hits the powder dispenser 82 achieved so that the powder is caused to immediately upon contact with the thread surface of the melted heated screw.

As shown in Figs. 1, 17, and 18, there is one single heating coil 410 between the screw collecting or storage device 76 and the plastic powder dispensing device 82 provided. It should be noted, however, that for certain sizes or types of screws it may be desirable that Two or more induction heating coils can be used, one in front of the powder dispenser 82 and the others can be arranged on the opposite side thereof to provide additional To provide heat, and thereby ensure complete melting of the plastic powder, the deposited on the threaded surface of the bolts.

Powder dispenser

The. Powder dispenser 82 is best seen in FIGS. 1, 17, 18, 30, 32, and 33. she owns preferably a funnel or a powder reservoir 416 in the form of a funnel, which at the lower end has a Has dispensing nozzle 418 which is concentric to the axis of the funnel 416. The funnel is on one vertical post 420 attached, in turn

is again fastened to the carrier base plate 320 in a suitable manner (not shown).

The powder dispenser also has a dispensing funnel 422, which preferably has a dispensing tube 424 on its underside. The dispensing funnel is designed so that tube 424 is eccentric with respect to the axis of tube 418. A powder dispensing attachment 426 is removably attached to the tube 424 and has a dispensing opening 428 on the lower wall 430. The dispensing opening 428 in the dispensing attachment 426 has a certain length, width and shape so that the plastic powder from the funnel 422 in a falling stream of predetermined shape and dimensions are given to create a plastic patch of predetermined shape and size on each screw.

It is emphasized that the dispensing hopper is disengaged 422 with its axis from the axis of the plastic powder reservoir 416, since it was found that such an arrangement ensures that the powder delivery rate substantially on the quantity of plastic powder within the reservoir 416 is independent.

The dispensing of the plastic powder from the funnel 422 can be facilitated by a vibrator 432, which preferably has the form of an electrically operated vibrator 434 , which is mounted on a holder 436 which is connected to the post 420 and to a ring 438 in which the hopper 422 is fixed and to which the hopper 422 is mounted so that it is vibrated by the vibrator 434 in the plane of the axes of the hoppers 416 and 422 at a rate that will allow the plastic powder to be dispensed from the hopper with a continuous uniform flow rate.

There may be a tendency for electrostatic charges to build up in the plastic powder as it flows out of funnel 416 and into and through dispensing boss 426. Such electrostatic charges can be easily removed by attaching an antistatic device 440 , which can be of conventional design, to the dispensing funnel.

It should be emphasized that, as shown in FIG. 32 shows the falling stream of plastic powder in the direction of the Forward movement of the screws has such a dimension that the desired arcuate part, less than 180 ° of the screw thread is covered. As shown in FIG. 30, the stream is of sufficient length to accommodate the desired number of To cover threads of the thread surface, but ensuring that at least one The thread turn at the beginning of the screw does not receive any powder.

It will be understood that a continuous stream of plastic powder is emitted from the neck 426 and that, although the screws are fed very closely together, there is sufficient clearance therebetween so that one screw is already out of the plastic stream before the next screw enters the stream. Accordingly, an excess powder collector 90 is provided, which is best shown in FIGS. 30 to 34 can be seen. It has a collection trough 442 located below the plastic dispensing boss 426 with the upper end lying vertically under the path of the screws and extending a substantial distance parallel to the path of the moving screws. The chute 442 is attached to a bracket 444 by bolts 446. The bracket is in turn attached to the conveyor box frame 246 by bolts 448, for example. An inverted funnel-shaped part 450 transfers the collected powder into a tube 452, through which it is guided into a collecting container 454. From there it can be fed back to the funnel 416.

Item acceptance device

The article picker 84 is. best seen in FIGS. 1, 18, and 36-38. It has a pair of take-off rails 456 and 458 positioned near the bottom line of belt 298 so that they grip the shafts and heads of the screws as the brackets move upward from idler 328 to front roller or wheel 326 start.

The removal rail 456 is provided with a nose 460 under which the screws are inserted by the holder. It also has a downwardly facing cam surface 462 which is designed to grip the head 60 of each screw and force the head of the screw down and away from the bracket as the screw moves under the removal rail. The rail 456 is attached to the inner end of a rail 464 which, in turn, is attached to a vertical rail 466 for adjustment in a horizontal plane to and from the path of the screws. The rail 464 is provided with slots 468 that receive mounting bolts 470 which are screwed into the lower end of the rail 466. The rail 466 is fastened to the box frame 246 , for example by bolts 472 which plug into slots 474. This type of fastening of the rail 466 to the box frame 246 allows the removal rail 456 to be adjusted in a vertical plane.

The supply to rail 458 has a shape similar to the decrease in rail 456. The nose portion 476 of the rail 458 hangs over the path of the shanks of the screws when the mounts begin their way to the tensioning wheel 328 upward. The take-off bar 458 is also provided with a downwardly sloping cam surface 478 which engages the shafts 56 of the screws and causes the shafts of the screws to move down and away from the mounts as the mounts move toward the wheel 326 move up. The pick-up rail 458 is attached to a horizontal rail 480 having slots 482 for receiving bolts 484 which are used to attach the track 480 to a vertical rail 486 so that the pick-up rail 458 can be moved horizontally to and from the screw holders.

The rail 486 is attached to the box frame 246 in the same manner as the rail 466 so that vertical adjustment of the removal rail 458 is possible.

A chute 488 is arranged with its upper end under the removal rails 456 and 458 in order to guide the screws into the receptacles 88 upside down.

Since, at least in some cases, the solidification of the plastic stains does not end when the removal When the screw enters, it is important that the screws moving down the chute, not the Touch the surface of the slide and that the plastic stain on these screws is also prevented from

7fla R97 / -M

touching other plastic stains. This is achieved by removing the screws from the brackets in such a way be removed that they are deposited on the slide in a certain way. For this purpose the removal rails 456 and 458 are adjusted, preferably in alignment crosswise to the belt 298, that the larger head of each screw first engages the cam surface 462 of the take-off bar 456 before the point in time at which the shank of the same screw touches the cam surface 478 the pick-up rail 458 touches. This ensures that the head of each screw is first touches the surface of chute 488 and then gravity causes the screw to hit the chute slides down (as seen in Fig. 38) so that the spot 62 is out of contact with the surface of the Slide is held with the screw oriented so that the spot of a screw does not match the spot of a touches another screw sliding down the chute and therefore does not stick to it.

Operation of the device

The motor 138 (Fig. 5) and the motor 312 (Fig. 17) are shared with electric vibrators 106 (FIG. 5), 168 (FIGS. 1 and 5), 276 (FIGS. 1 and 5), and 434 (Figs. 17 and 18) is turned on, a lot of screws are thrown into the funnel 104 and the pusher 102 is adjusted so that a smooth flow of screws from the bottom of hopper 104 onto the surface of the Belt 110 of the article feeder 70 is ensured. The screws will be in arbitrary The assembly is guided by the belt 110 from the hopper 104 to the article aligner 74 and is dispensed into the inclined trough of the article orienter. If the screws are under the Action of gravity, assisted by vibrator 168, move the trough down, then the The majority of the screws have one layer, as shown in FIG. 9 is explained where they go through the lower edges of the Trough sidewalls 144 and 146 are retained and their shafts extend downward. As mentioned above, the strips support the alignment of the screws in the position and position just described also serve to loosen groups of screws that are intertwined with one another.

As the bottom edges of the trough sidewalls fit into the top surfaces of rails 172 and 174 pass over, the aligned screws continue their forward motion due to gravity which Rails 172 and 174 continue down and run over the funnel 184 of the collector 77 for not aligned items and then enter the item collection or storage facility 76. The screws are collected or stored in the vertical guide 208, with a maximum upper or minimum lower height, as described above, is observed. From the vertical guide the screws are sequentially attached to the continuously moving magnetic mounts 296, the are on the main conveyor belt 298 is fed. When the screw from the vertical guide through a magnetic holder is moved away, then the head of the screw contacts the object positioning wheel 360, causing the screw to move transverse to the bracket and the starting end of the Screw thread comes into contact with an alignment rail 390 so that the screws when they move from move the vertical guide to the heating device and then to the powder dispensing device, in an exactly specific position in the transverse direction on the screw holders. The magnetic holder 2% carry the screws sequentially between the rods 412 and 414 of the induction heating coil and then under a stream of powder delivered by powder dispenser 82. As already described, is a predetermined limited amount of plastic powder determined by the shape and size of the dispensing opening 428 and the powder dispensing projection 430 and by the speed of the Movement of the tape determined is deposited on the shank of each heated screw. The powder when it touches the hot thread surface of each screw, it melts and forms a liquid stain of the selected thermoplastic material.

When the tape the screws with their patches of thermoplastic material that is on the threaded surfaces the screw sticks, moves forward, then the screws can cool down, causing the Spots become solidified and bond with the part of the thread surface exposed by the melted thermoplastic material is wetted. The screws that are magnetically attached to the tape by the magnetic holder 296 are then retained at the end of the top flight of the belt and then worn along the lower line of the belt until the screws one by one the Contact cam surfaces 462 and 478 of pick-up rails 456 and 458, respectively. You will then be removed from the magnetic mounts are dispensed into chute 488, from where they are placed in a receptacle or in an oil quench tank.

Screw mounts of modified form

The first modified form of screw mounts is shown in FIGS. 39 and 40. Everyone Modified screw holder 296 'has a permanent magnet plate 500 sandwiched between a pair of magnetic Plates 502 and non-magnetic outer plates 504 is arranged. The permanent magnet plate 500 and the magnetic plates 502 do not extend as far in the longitudinal direction of the tape as that non-magnetic plates 504 and therefore have in this modified form of the screw holder 296 ' the magnetic plates of adjacent holders have a greater spacing than in the case of the magnetic holders 296. As a result, the lines of flow of adjacent holders 296 'do not interfere to the same extent in interaction, like the lines of flux of adjacent holders 296, and it is therefore not necessary that the magnetic plates of adjacent holder 2% 'are oriented in the same way as in Fig. 26th is explained.

A second modified form of screw mount is shown in FIGS. 41 to 45 explained. As can be seen, the brackets 296 ″ have a plate 506 that attaches to the strap 298 in the same manner as the brackets 296 is. each plate 506 is integrally provided at its rear end with an extension 508, so that a Object gripping shoulder 510 is formed. A lever 512 'is in the middle between its ends on the Plate 506 pivotally mounted, the upper end of the lever being configured to have a screw retaining pawl 514 is formed with the shoulder 510 for holding a screw on each retaining plate 506 cooperates. Each lever 512 has an actuating roller 516 at the lower end.

The lever 512 can be located within a suitable recess in a surface of the holding plate 506 , the recess being sufficiently large that the necessary pivoting movement of the lever 512 is ensured. The pivot device for the lever 512 preferably has a bolt 520 which is screwed into the plate 506. A spacer sleeve 522 encompasses the bolt 520 and telescopes with a torsion spring 524, one end of which is seated in an opening 526 in the lever 512 and the other end in an opening 528 in the plate 506. The torsion spring 524 urges the lever 512 in one direction so that it presses the shaft of a captured screw against the shoulder 510 of the mounting plate 506. In order to move the lever 512 in a direction that the article holding claw 514 is moved away from the article holding shoulder 510 in order to release the screw from the holder, the article removing device 86 is replaced by an article removing device 86 ' , which preferably consists of a cam rail 530 , which extends from a location near the tension pulley 328 along the belt in the forward direction of that pulley along the upper line of the belt to a location near the vertical guide, as shown in FIG. 41 is shown. At the lower end, the rail 530 is provided with an inclined cam surface 532 which comes into abutment with the roller 516 of each bracket in turn, moving the lever 512 in a direction to move the pawl portion 514 away from the corresponding screw retaining shoulder 508 , whereby the Screw is released and due to gravity from the holder on the screw delivery chute, such. B. the slide 488 of FIG. 37 and 38, falls. At the upper end, the rail 530 is provided with an inclined cam surface 534 which allows the roller 516 of each screw holder to move counterclockwise as seen in Figure 41 under the action of the spring 524 which moves the lever part 512 into screw clamping position just as the lowermost screw in the vertical guide is moved sideways in the direction of advance of the belt by the shoulder 510 coming into contact with the shaft of the lowermost screw. Between the lower and upper ends, the outer surface 536 of the rail 530 abuts each roller 516 and holds the lever 512 in the release position when the bracket moves along the rail 530.

The bracket 296 ″ can be used for screws made of non-magnetic material, as well as for screws made of magnetic material can be used.

The described device and the described method, including the holder 296 , have been used successfully during long production ^{times to produce the described spots on 3} -inch screws at an average production rate of more than 600 / min.

It has been found that the adhesion of the stains can be improved if a suitable primer, such as B. an epoxy is applied to the screws prior to the application of the stain. This can be done by Diving done in a known manner.

In addition 12 sheets of drawings

Claims (12)

Patent claims: 1. Method of making self-locking screws by applying a stain thermoplastic material on an axially limited part of the thread surface, thereby characterized in that the plastic material is in the form of a constantly flowing powder stream with abandoned a cross section corresponding to the size of the spot from a supply source is further that the threaded screws are taken from a disordered supply, aligned with respect to their axes, fed to a conveyor track, to a temperature above of the melting point of the plastic material and one after the other with crosswise to the powder flow lying axes along the conveyor track are moved through the powder flow, only the axially limited part of the thread surface in contact with the powder flow arrives, and that then the screws without exerting a forming pressure on the adhering The stain can be cooled to below the solidification temperature of the plastic material. 2. The method according to claim 1, characterized in that the cross-sectional shape of the powder flow is precisely controlled. 3. The method according to claim 1 or 2, characterized in that the screws in exactly can be moved through the powder flow in a fixed position. 4. The method according to claim 3, characterized in that the relative position of the screws is adjusted with respect to the powder flow. 5. The method according to claim 3 or 4, characterized in that the screws with horizontal lying longitudinal axes are moved through the powder flow, while the powder flow is formed freely from top to bottom to fall. 6. The method according to any one of the preceding claims 1 to 5, characterized in that before passing the screws through the powder stream onto the axially limited part of the A primer is applied to the thread surface. 7. Device for performing the method according to one of claims 1 to 6, characterized characterized in that a delivery device (82) is provided for the powder flow that in the area of the Powder stream a conveyor (78), which the screws (55) with transverse to the path and to Powder stream aligned longitudinal axes promotes, and that in the area of the conveyor (78) a Heating device (80) is provided with which the screws (55) open before reaching the powder flow heated to a desired temperature. 8. Apparatus according to claim 7, characterized in that the conveyor (78) is provided with holding elements (296) which fix the screws in position on the conveyor (78). 9. Apparatus according to claim 7 or 8, characterized in that the dispensing device (82) has a funnel (422) with a vertically lying axis, which is coupled to a vibrator (432). 10. Apparatus according to claim 9, characterized characterized in that a plate (426 ) provided with an opening (428) can be attached to the lower end of the funnel (422), the opening (428) being dimensioned according to the desired cross-sectional shape of the powder flow (FIG. 30). 11. The device according to claim 9 or 10, characterized in that a further funnel (416) is arranged above the funnel (422) , the vertical axis of which is offset from the vertical axis of the lower funnel (422). 12. Device according to one of claims 7-11, characterized in that the heating device (80) is arranged along the conveyor (78) Induction heater is.