GB2216215A

GB2216215A - Integral series of screws

Info

Publication number: GB2216215A
Application number: GB8903249A
Authority: GB
Inventors: Kurt Stoll
Original assignee: Festo SE and Co KG
Current assignee: Festo SE and Co KG
Priority date: 1988-02-22
Filing date: 1989-02-14
Publication date: 1989-10-04
Anticipated expiration: 2009-02-14
Also published as: GB8903249D0; DE8802247U1; GB2216215B

Abstract

In an arrangement with screws each has a shank whose head at one end thereof has an engagement part for a screw drive tool. The head has an end surface facing away from the shank and a peripheral surface between the end surface and the shank. The screws are formed into a row with identical orientation in sequence and are assembled as an integral chain, screws adjacent to each other in the longitudinal direction of the chain being formed together by an intentionally frangible means having a reduced material cross section. The frangible means is located on one screw of at least a pair of screws which are respectively formed together on the respective screw head adjacent to or at the edge of a tool engagement part (16) between the end surface (5) and the peripheral surface (6), and on the other screw of the pair on the end part of the shank (3) opposite the head (4). Screws 1 are joined together integraliy to form a continuous strip 2 or 2' either head-to-tip as shown in Figure 1 or side-by-side as shown in Figure 3; in either case the screws 1 are joined by shearable webs 14 located on the side of each screw head 4. In Figure 1, the webs 14 are at the junction between the end surface 5 and the peripheral surface 6 of the screw head; in Figure 3 the webs 14 are at the junction between the peripheral surface 6 and the screw shank 3. Either junction may be provided with a rim on which the webs 14 are formed. The screw strip 2' may be straight or coiled with the screws parallel to the axis of the coil. <IMAGE>

Description

A Screw Arrangement.

The invention relates to an arrangement of screws and more particularly but not exclusively to such an arrangement with screws each having a shank whose head at one end thereof has an engagement part for a screw drive tool, such head having an end surface facing away from the shank and a peripheral surface adjacent to such surface and placed between the end surface and the shank, such screws being formed into a row with identical orientation in sequence and assembled as an integral chain, screws adjacent to each other in the longitudinal direction of the chain being formed together by an intentionally frangible means having a reduced material cross section, such means being located at one screw at least of a pair of screws which are respectively formed together.

Such chain-like screw arrangements have the advantage over a loose or bulk arrangement of screws that the screws are present in a longitudinally orientated manner and may be taken one by one from the chain without any trouble just as they are needed. This is more especially an advantage in the case of automatically performed working operations, in which the screws are automatically gripped by gripping tools, handling devices or the like in order to be screwed into a hole at some desired position on a workpiece or the like later. The chain of screws is in this case made in the form of a single member, for example by injection molding. The intended point of break or frangibility is then so designed that it on the one hand ensures a sufficiently strong connection and on the other hand the possibility of being readily broken.However it has so far been a disadvantage that the individual screws in the chain are arranged in such a manner that their longitudinal direction coincides with the longitudinal direction of the screw chain. Thus at each point of intended breakage the end of the shank of one screw is molded centrally on the adjacent end surface of the head of the other screw. This renders it impossible to provide the individual screws with conventional engaging parts such as slots or philips cross slots during the process of manufacture so as to make it possible for conventional tools to be used in conjunction with the screws. In the case of the screw heads adapted thereto the engagement parts are regularly exactly at the position at which the intended position of break is arranged.For this reason it has so far been necessary to provide a special design of the engagement parts, something that makes possible the use of expensive special purpose gripping tools or the like or the engagement parts have to be applied after separation of the individual screws in a further time-consuming operation. A further point is that the intended points of breakage of the known chain arrangement are considerably bent on winding up in a coil, for example on a drum and this may lead to accidental and undesired breaking at the intended point of breakage. A further fact is that at the intended points of breakage flash or jagged edges remain at exposed parts of the material after separation of the screws and that such jagged edges may impede the application of a screw driver to the screw.

One object of the present invention is to provide a screw arrangement of the initially specified type in the case of which the screws when formed into a chain are able to have engagement parts with a conventional design, and in the case of which the intended position of break does not require any further processing and in the case of which accidental breakage during handling the chain, as for instance during winding up as a coil, is avoided as far as possible.

In order to achieve these or other objects appearing from the present specification, claims and drawings a screw arrangement is provided with screws each having a shank whose head at one end thereof has an engagement part for a screw drive tool, such head having an end surface facing away from the shank and a peripheral surface adjacent to such surface and placed between the end surface and the shank, such screws being formed into a row with identical orientation in sequence and assembled as an integral chain, screws adjacent to each other in the longitudinal direction of the chain being formed together by an intentionally frangible means having a reduced material cross section, such means being located at one screw at least of one pair of screws which are respectively formed together the intentionally frangible means located on the respective screw head being placed adjacent to or at the edge of the tool engagement part and in the peripheral part between the end surface and the peripheral surface or between the peripheral surface and the shank.

It is in this manner that it one may ensure that the actual tool engagement surface remains free of any excess material which is left after breaking at the point of intended breakage. There is no difficulty to provide a slot or two crossing slots on the end surface of the screw heads opposite to the shank without the screw, after separation from the chain, having to be processed in any way. In this respect the intended point of break is preferably located in the transitional zone between the end surface and the peripheral surface. In a case in which the screw head is provided with a polygonal form as a nut, as for example in the form of a hex nut in order to make possible the use of a spanner, the intended point of break may with advantage placed in the zone between the peripheral surface and the shank.This furthermore makes it possible to apply a socket wrench to the screw head from the end surface thereof without any previous preparation of the screw head having been necessary for this. A further advantage is that the arrangement of the intended positions of break in accordance with the invention makes it easier to store the chain in the form of a coil, since the flexural load on the break points is reduced so that there is less danger of an accidental detachment of individual screws. A further point is that the screw driving tool or gripper may be applied in the head part to the part to be engaged by the tool even while the individual screws are still in their condition connected together in the chain, since the engagement part is freely accessible.This facilitates handling to a considerably extent, since the screws, as long as they are part of the train, are precisely aligned in the longitudinal direction and thus specifically adapted for automatic engagement, whereas engagement which is only able to take place after detachment, is more likely to be unsatisfactory since alignment sometimes leaves to be desired.

Further advantageous forms of the invention are described in the claims.

It is preferred for the screws to be arranged so that they are transverse in relation to the longitudinal direction and are substantially parallel to each other, the peripheral surfaces of adjacent screw heads being close to each other and the point of intended break on the two screw heads being provided between the peripheral surface of the head and the shank. In this respect it is convenient to have a gap between two adjacent screw heads, such gap being more especially as a guide gap for separating too. This facilitates the separation of the individual screws, since the separating tool is guided in the gap so that the screws may be separated at the point of intended break.Furthermore the screws are then supported since during the operation of separation by their peripheral surfaces laterally resting on the cutting or separating tool so that displacements in position, skew positioning or the like are out of the question and an exact and clean cut is produced and there are hardly any irregular pieces of material left on the screws. Such an arrangement also facilitates the coiling of the chain of screws to a coiled body with the longitudinal axis of the coiled body parallel to the longitudinal direction of the individual screws and the plane of the coiled body running at a right angle to the longitudinal direction of the individual screws. In this case the screw heads are placed close together so that a large storage capacity is achieved and furthermore the mobility of the individual screws is considerably limited when the chain is being handled, as for instance during shipping, so that accidental separation of the screws at intended positions of break is practically eliminated. The intended positions of break are more especially, as seen in the longitudinal direction of the chain, arranged on the longitudinal axis of the chain. The screw heads may have a step or rim between the peripheral surface and the shank, this considerably facilitating separation.

It is furthermore possible for the screws to be arranged to be oblique to the longitudinal direction of the chain, the position of intended break between each pair of screws formed together in the chain is located on the respective one screw at the head thereof in the peripheral zone between the end surface and the peripheral surface and on the respective other screw on its shank end part opposite to the head. In this case as well the engagement part is accessible at all times for a wrench or screw driver and a further point is that on coiling up the chain to form a coiled body both the head part and also the shank part of each respective screw is laterally supported by the adjacent coil so that even if there is a laterally directed thrust load unintended separation of the screws is not possible.The separating operation is facilitated and furthermore manual separation is possible, more especially, if the screw heads have a surrounding edge between the end surface and the peripheral surface, the position of intended break being provided on this edge. In the formed rolled up as the coiled body the screw longitudinal axes are preferably arranged in the plane of the coiled body, this considerably reducing the breadth of the coiled body and making it possible to arrange a number of coiled bodies with different types of screws in a very restricted space.

If the tool engagement parts of the individual screws of a chain are identically orientated in relation to the longitudinal direction of the chain it is then possible to coordinate the use of automatic gripping and screw driving tools.

It is furthermore an advantage if that the chain of screws may selectively assume a linear form or a coiled one such as a helical form so that dependent on the particular application the chain may be stored in a magazine in a linear or coiled form. Thus a single type of chain may be provided for different uses.

The invention will now be described with reference to the embodiments thereof shown in the accompanying drawings.

Figure 1 shows a first embodiment of the screw arrangement in accordance with the invention in a condition wound up on a transport drum.

Figure 2 is a plan view of the structure of figure 1 looking in the direction of arrow II.

Figure 3 shows a further example of the screw arrangement in accordance with the invention with a partial longitudinal section as taken on the line III-III of figure 4 and arranged in a transport slide.

Figure 4 shows a cross section taken through the arrangement of figure 3 taken on the section line IV-IV.

Figure 5 shows a further working example of the screw arrangement in accordance with the invention with the slide shown partly broken open.

Figure 6 shows a further working embodiment of the screw arrangement in a condition arranged in a magazine and in a cross section taken on the line VI-VI of figure 7.

Figure 7 is a section taken through the device of figure 6 taken on the section line VI-VI.

The individual figures of the drawing each show, inter alia, an arrangement of individual screws 1 which are joined together to form a screw chain 2 and 2. The screws 1 each have a shank 3 and a screw head 4 formed on the end thereof. On the side opposite to the shank the head 4 has an end surface 5 and a peripheral surface 6 between this end surface and the shank. The end surface 5 and the peripheral surface 6 may merge with each other smoothly and the head may be in the form of a round or filister head as in the embodiment, in the case of which the peripheral surface 6 is in the form is formed by a cylindrical surface. The two surfaces 5 and 6 merge in the form of a circular or angular edge 7.The transition from the peripheral surface 6 to the shank 3 is preferably in the form of a step 8, which is due to the fact that the shank 3 having the smaller diameter is formed on the base surface 9 of the head opposite to the end surface 6 and having the larger diameter.

The individual screws 1 of a respective chain 2 and 2' are arranged in a sequential chain so that they have the same orientation inter se and more particularly in relation to the longitudinal axis 10 of the chain the chain. This more especially means that the screw heads 4 are also orientated identically in the peripheral direction in relation to the longitudinal axis 10.

Screws 1 which are adjacent to each other in the longitudinal direction 10 are integrally formed together with the provision of a link or intermediate connection having an intended break point 14. A chain of members thus represents an integral and coherent unit which is for instance produced in the course of an injection or casting molding operation, the material used for instance being plastic or zinc. At the individual intended breaks 14, that is to say at the points at which the individual screws are joined together, the cross section of the material is selected so as to be relatively small so that although a sufficiently firm connection is provided along the chain, there is however still the possibility of sequentially separating the individual screws from each other as they are needed.Such separation is preferably performed mechanically with the aid of knife-like cutting tools 15 (as diagrammatically indicated in figures 3 and 5), although such separation may also be carried out by cutting or breaking off.

The heads 4 of the individual screws each respectively possess an engagement part 16 and 16' for the correct application or fitting of a screwing tool such as a screw driver or a socket wrench, not shown in detail. In figures 1 and 2 the engagement part 16 is formed on the end surface 5 in the form of a slot for the application of a screw driver. In the case of the figures 3 through 5 it is a question of intersecting slots, which are also provided on the end surface 5. On the screws of figures 6 and 7 the engagement part 16' is located cn the peripheral surface 6 and is in the form of a polygon, that is to say specifically in the form of a hex nut so that a spanner or the like may be applied thereto.

A more detailed account will now be given starting with the embodiment shown in figures 1 and 2. In the case of this working example of the invention the individual screws 1 are slightly inclined in relation to the length direction 10 of the train so that between the longitudinal axis 17 of the screws and the longitudinal axis 10 of the chain there is a substantially acute angle at the respective screws. Dependent on the length and thickness of the individual screws the angle may also be larger.

The intended position of break is in the case of each pair of screws arranged on the one screw 1' on its head 4 and on the other adjacent screw 1" it is on its shank. Thus the head of one screw is connected with the shank of the following screw, if the arrangement is looked in a direction 18 along the longitudinal axis 10. In this respect it is significant that the intended point of break 14 on the respective screw head 4 is arranged alongside the slot-like tool engaging part 16 and is preferably located in the part joining the end surface 5 and the peripheral surface 6. Since in this embodiment is in the form of a rim 7 or edge, the intended point of break 14 is more especially on the latter, something that simplifies separation.On the molded on shank of the following screw 1" the intended point of break is conveniently at the end part, opposite to its head 4, of the shank, which is for instance provided with a rounded head or a conical head, the intended point of break 14 being located in the latter case more especially at the end of the shank.

In the working embodiment the intended point of break 14 on the shank is placed on the flank 19 of the conical shank end part so that the shank 3 of the respective screw has its end part to the side of the head, formed to extend over the intended point of break, of the following screw. Such a design offers advantages more especially when the screw chain 2 is rolled up for placing it in the magazine and forms the coiled member 20 as shown in figure 1.In this case the chain 2 of screws is wound up on the cylindrical core 21 of a drum member 22 so that the longitudinal axis 10 of the chain describes a spiral and as seen looking radially outwards there are a plurality of turns 24 of the chain placed on top of each with reference to the longitudinal axis 23 of the core (in figure 1 the individual screws 1 of the chain 2 are only shown at a few points, while in other respects they are only indicated in broken lines).

Owing to the lateral offset as described of each end of a shank in relation to formed on head there is the advantage that the individual screws in a turn 24 of the chain have both their head part and also the shank end part resting against the radially inner adjacent turn 24 of the chain or, in the case of the innermost turn, on the periphery of the drum core 21. The entire coiled body 20 is in this manner endowed with a high degree of firmness and the intended point of breaks 14 are supported in the radial direction so that accidental breaking off of screws, as for example when the screws are subject to an external blow is out of the question.

In the case of the illustrated working example the longitudinal axes 17 of the screws are arranged in the plane 25 of the coiled body 20 so that its breadth is substantially dependent on the breadth of the heads of the individual screws. The coiled member 20 thus has a very narrow overall breadth in the direction of the longitudinal axis 23 so that it is possible to arrange a plurality of coiled bodies 20 in a small amount of space, as for example with different types of screws. The intended point of breaks 14 are preferably aligned with each other on a common line of winding in the wound up state, such line in the present case being aligned with the longitudinal axis 10 of the chain or a line parallel thereto.

In order to make it readily possible to unwind the wound body 20. there are plate-like limiting walls 29 on the axial sides of the core 21 and which delimit the coil space 30 for the coiled body 20 and the core is provided with an axle 23 which 23 which is rotatably supported on two bearing blocks 32 connected with each other so that the drum body 22 may be supported on something such as a table 33 in the position where it is needed.

Removal of the screws may be simply performed by unrolling the coiled body in the direction of the arrow 18 and if required the respectively foremost screw may be broken off the free end of the chain of screws or detached therefrom in some other way.

In the working examples shown in figures 3 through 7 the screws 1 of the chain 2' are arranged to run transversely in relation to the longitudinal direction 10 so that they are parallel to each other. The longitudinal axes 17' of the screws are thus more especially at a right angle to the longitudinal axis 10 with the peripheral surfaces 6 of adjacent screws being placed opposite to each other and adjacent. The intended point of breaks 14 are in this case, in relation to a respective pair of screws, placed between the two screw heads 4 and they are located in the transitional zone between the peripheral surface 6 and the shank 3. Since in the working exqmple this zone is in the form of a step 8, the respective intended point of break 14 is more particularly located between the peripheral surface 6 and the base surface 9 of the head, this simplifying detachment of the screws.

Between two adjacent screw heads 4 there is a gap 34 which depends on the thickness of the intended point of break 14 and which preferably forms a guide gap for a detaching tool.

In this respect attention is to be paid more especially to figures 3 through 5, in the case of which the screw chain 2' has a linear form and is arranged in a linear extending shipping or packing rail 36. This rail 36 has the form of a hollow section with a rectangular or square cross section which on one side has a longitudinal slot 37. The chain 2' of screws is inserted into the rail 36 from an end thereof not illustrated, that is to say from the fitting side, the screw heads 4 being arranged with a sliding play in the interior of the rails, while the shanks 3 extend outwards through the slot 37. The fitting side or end may be provided with a compression spring, which loads the screw chain in the longitudinal direction of the rail and presses against the opposite towards a limiting wall 38.In the end part adjacent to this wall 38 the rail 36 has an opening 39 for a tool, which makes it possible for the detaching tool 15 to be inserted. The tool 15 may be moved backwards and forwards as indicated by the double arrow. If the tool 15 is inserted through the opening 39 into the rail 36, it will firstly be guided by the gap 34 and at the same time the screw chain 2' will be guided so that in the end cutting of the chain may take place exactly at the intended point of break 14. The detached screw 1 may then be removed through an opening 34 in the rail or may drop out under its own weight.

While the magazine, which has a linear extent, in the form of a shipping or packaging rail is more especially suitable for small amounts of screws in the case of the magazine shown in figure 6, in the case of which the longitudinal direction of the chain has a curved form, the design is more especially suitable for chains 2' with a larger number of screws. In this case as well a packaging rail 44 is used, which however may be in the form of a channel section (see figure 7) and which as shown in figure 6 is preferably so bent that it assumes a slightly spiral form, the opening of the channel being directed radially inwards. The heads 4 of the screw chain 2' are set in the channel rail and are loaded by a spring loaded rotary lever 45 in the feed direction 46.The part with the removal end 4 ig more especially design as in the case of the packaging rail 36 in figures 3 through 5 so that after the detachment at an intended point of break and removal of one respective screw there is an automatic stepped follow up motion of the screw chain 2' The magazine of figures 3 through 5 may be readily refilled by insertion of further screw chains; the so-called round magazine containing the rail 44 of figures 6 and 7 may simply be refilled by the insertion of a further chain of screws from the open side of the channel.

It will be clear that the chain of screws as shown in figures through 6 may also be coiled up in the form of a coiled body. In this case, as is also the case with the magazine system in accordance with figure 6, the longitudinal axis of the coiled body is best arranged parallel to the longitudinal axis 17' of the individual screws 1, that is te say the plane of the coiled body in this case extends at a right angle th the longitudinal direction 17' of the screws.

In any case, as seen in the longitudinal direction of the screws 1 the intended point of breaks 14 are preferably on the longitudinal axis 10 of the chain.

A more particularly significant advantage of the screw arrangement in accordance with the invention is that the tool engagement parts 16 and 16' of the individual screws 1 of a respective chain 2 and 2' have an identical orientation in relation to the longitudinal direction 10 of the chain so that an automatic detachment of the individual screws by means of a gripping device, not shown in detail here, is possible in a simple manner. It is convenient if a respective screw is gripped even before the separation at the intended point of break and after detachment is placed at the desired position and then the screw driving tool is applied thereto which owing to the exact orientation of the engagement parts 16 and 16' is exactly placed in the desired position.

A feature common to all forms of the invention is that the intended point of break is placed near to or at the edge of the respective tool engagement part 16 and 16' so that the design thereof is not influenced and no later processing after the detachment, of the screws is needed.

Claims

1 An arrangement with screws each having a shank whose head at one end thereof has an engagement part for a screw drive tool, such head having an end surface facing away from the shank and a peripheral surface adjacent to such surface and placed between the end surface and the shank, such screws being formed into a row with identical orientation in sequence and are assembled as an integral chain, screws adjacent to each other in the longitudinal direction of the chain being formed together by an intentionally frangible means having a reduced material cross section such means being located at one screw at least of one pair of screws which are respectively formed together, the intentionally frangible means located on the respective screw head being placed adjacent to or at the edge of the toll engagement part and in the peripheral part between the end surface and the peripheral surface or between the peripheral surface and the shank.

2 An arrangement as claimed in claim 1 wherein the screws are arranged transversely in relation to the longitudinal direction of the chain and are arranged substantially parallel to each other and the peripheral surfaces of adjacent screw heads are alongside each other and the intentionally frangible means is provided on both screw heads in the transition part between the head peripheral surface and the shank.

3 An arrangement as claimed in claim 2 wherein there is a gap between two adjacent screw heads.

4 An arrangement as claimed in claim 3 wherein the gap ls a guide gap for a detaching tool such as a knife blade.

5 An arrangement as claimed in any one preceding claim chain wherein the/is coiled up and forms a coiled body whose longitudinal axis is parallel to the longitudinal direction of the screws and the plane of the coiled body is at a right angle to the longitudinal direction of the screws.

6 An arrangement,as claimed in any one of the claims 1 through 5 wherein intentionally frangible means are arranged, as seen in the longitudinal direction of the screws, on the longitudinal axis of the chain.

7 An arrangement as claimed in any one of the claims 1 through 6 wherein between the peripheral surface and the shank of the screw shank the screw heads have a step or a rim on which the frangible means is arranged.

8 An arrangement as claimed in claim 1 wherein as seen in the longitudinal direction the screws are arranged obliquely to this direction and the frangible means of the respectively formed together pair of screws is located on the respective one screw on the head thereof and the peripheral surface and on the respectively other screw on the end part of the shank thereof opposite to the head.

9 An arrangement as claimed in claim 8 wherein the screw heads have a circumferential rim between the end surface and the peripheral surface and the frangible means is arranged on such rim.

10 An arrangement as claimed in claim 8 or claim 9 wherein the shank of a respective pair of adjacent screws has its end part, which has the frangible means, at least partly adjacent to the head, as seen in the longitudinal direction of the chain, of the formed-on next screw.

11 An arrangement as claimed in any one of theclaims 8 through 10 wherein the chain of screws is coiled up and forms a coiled body, and the longitudinal axes of the screws are arranged in the plane of the coiled body.

12 An arrangement as claimed in claim 11 wherein shank ends having the frangible means and the radially inwardly direction head parts of the screws of a screw chain forming a coiled body are generally arranged on a common line of coiling.

13 An arrangement as claimed in claim 11 or claim 12 wherein the shank ends having the frangible means and the radially inwardly directed head parts of the screws of a respective turn of the coiled body are rested on the radially inwardly adjacent chain turn and/or are directly adjacent thereto.

14 An arrangement as claim in any one of the claims 1 through 13 wherein the tool engagement parts of the screws have the same orientation with respect to the longitudinal direction of the chain.

15 An arrangement as claimed in any one of the claims 1 through 14 wherein the longitudinal direction of the chain is linear.

16 An arrangement as claimed in any one of the claims 1 through 14 wherein the longitudinal direction of the chain has a curved or bent form.

17 An arrangement with screws substantially as described hereinbefore with reference to the accompanying drawings.

18 Any novel subject matter or combination including novel subject matter herein disclosed in the foregoing Specification or Claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding Claims.