GB2155985A

GB2155985A - Bayonet fastening

Info

Publication number: GB2155985A
Application number: GB8404033A
Authority: GB
Inventors: Malcolm Gordon Victory
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-02-16
Filing date: 1984-02-16
Publication date: 1985-10-02
Also published as: GB2155985B; GB8404033D0

Abstract

The fastening comprises lugs or spigots 10 on one element of the mechanism which align with impressions or scrolls 11 on the second element of the mechanism which are shaped somewhat in the form of a tick ( 2ROOT ) so that when the two elements are rotated contrary to one another they are drawn together and lock into place. Where necessary a pliant seal, spring washer or ring of compressible material 14 or a spring is provided to exert sufficient pressure to retain the two elements in the 'locked' position and to provide a positive seal. The closed end of the scroll 11 may have an abutment to prevent separation of the elements merely by reverse rotation. The fastening may be applied to bottle stoppers, pipe couplings bulb holders and screw or bolt fixings. <IMAGE>

Description

SPECIFICATION Easily operated fastening device This invention relates to a fastening or locating device.

Fastening or locating devices take many forms and have many applications. They frequently use a helical scroll or screw thread, in such diverse applications as bottle tops and nuts and bolts. Scroll and threads can be fine or coarse threads and may be "single start" or ''multi start". Their function is to provide a simple and effective method of attaching one constituent part of a product to another constituent part, or an accessory thereto. The helical scroll has many advantages in that engineering parameters such as torque requirements and inherent strength can be accommodated within a variety of basic patterns.

However, most screw threads require a considerable angular movement before they become tight. Furthermore, the extent of sealing depends on the torque applied. A coarse thread, multi-start scroll fastener requires a small angular movement to secure but the sealing force is smaller and the fastener can easily slacken back. The natural consequence is that the two elements of the fastener are attached too tightly or too loosely.

According to the present invention such drawbacks are overcome by providing evenly spaced lugs or spigots on one constituent part of the fastening device which correspond with impressions or scrolls on the other constitutent part which are angled so as to provide a guide for the spigots in order to draw the two parts together when rotated contrary to each other. In general applications the "right-hand thread" convention will be followed and the impressions or scrolls will thus take the form of a tick (/) as used in marking papers since a small portion of "left-hand thread" terminates the impression or scroll at the extreme limit of rotation. The acute angle between left and right portions of the impression or scroll may be radiused if required.Also applied where necessary is a method of applying a compressive force, e.g. a spring washer or an insert of compressible material to allow for the slight diminution of pressure as the lugs or spigots pass the lowest part of the "tick" and yet retain sufficient compression to provide a positive locating force or a positive seal as required by the specific application. Once fully engaged the connection cannot be undone by vibration but yet can be easily undone by reversing the turning action with or without downward pressure to disengage the lugs or spigots from the reverse portion of the impression or scroll. Secure fastening of this invention is thus not dependent on friction.

The number of lugs or spigots and corresponding impressions or scrolls can be varied according to the size and usage of the elements to be connected although the optimum number is expected to be five lugs or spigots.

Should the application require a tamperproof seal such as is provided on medicine bottles the impression or scroll is shaped to provide horizontal motion relative to the plane of attachment at the end of the impression wherein the spigot rests when the elements are fastened together, the lugs or spigots perhaps having a triangular section with their upper face horizontal to the place of attachment.

Should the application require location in a certain plane or direction this is accommodated by an uneven spacing of the lugs or spigots and their respective impressions or scrolls. If desired, the right hand face of the impressions (using the conventional model as described above) could be made horizontal for some small distance at its upper end in order to guide the lugs or spigots more easily into the impressions as the left hand face would then present a raised lip to the lugs or spigots as they are turned clockwise.In applications such as securing a domestic light bulb the device can accept the existing bayonet light bulb which has two circular spigots projecting from opposite sides of its base by the provision of two impressions, scrolls or cutaways as described above, the compressible material described above being in the form of a spring which presses the electrical contacts within the holder against the relative contacts on the base of the light bulb and retains the light bulb in the locked position until removed by anticlockwise rotation.

Specific embodiments of the investion will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows the basic principle of the invention; Figure 2 illustrates the example of a sauce bottle using the invention; Figure 3 shows the extension of the basic principle in order to provide a seal which would be difficult for infants to open; Figure 4 shows the alternative location of lugs or spigots and impressions or scrolls using the example of a toothpaste tube; Figure 5 shows the example of a replacement for a conventional nut and bolt or stud; Figure 6 shows the example of a potentiometer fastened to an amplifier chassis; Figure 7 shows the example of two tubes or pipes bing attached using a sleeve of larger diameter; Figure 8 shows the example of a flywheel attached to a shaft;; Figure 9 shows the example of a recessed fitting for use in woodwork or masonry; Figure 10 shows the example of a conventional woodscrew with the device incorporated on its parallel section; Figure 11 shows the example of a holder for a typical 'bayonet fitting' light butS.

Referring to the drawings the lugs or spigots 10 are guided into place by the impressions or scrolls 11 when the parts to be fastened are rotated in opposing directions until the lugs or spigots 10 lock into place.

For convenience, a conventional clockwise motion is assumed for fastening and the spring washer or compressible material 14 is not shown in all cases.

In Figure 1 the impression 11 forms the path for the spigot 10 and causes it to be retained on its left hand apex when a force is applied leftward upon the spigot 10. From this point a force applied rightward will cause it to leave the impression 11.

In Figure 2 this basic principle is shown as related to the fastening of a lid 12 to a sauce bottle 13. The illustration shows five spigots 10 on the lid 12, which could alternatively be formed on the bottom inner flange of the lid 12, aligned with five impressions 11 in the top of the sauce bottle 13 before the action of fastening. Optional extensions 15 to the impressions are shown in dotted line. As the lid 12 is lowered on to the bottle 13 the spigots 10 mate with the impressions 11 and the lid 12 is then rotated clockwise relative to the bottle 13. As the spigots 10 reach the lowest part of the impressions 11 a pliant seal 14 within the lid 12 forms an airtight seal with the bottle 13 and exerts an upward force on the lid as the seal 14 is compressed.Such force is only partly released as the spigots 10 reach the end of their permitted movement clockwise within the impressions 11. Anticlockwise movement of the lid 12 relative to the bottle 13 will again compress the seal 14 until at a set pressure the spigots 10 will again be free to travel within the impressions 11 until the lid 12 is free of the bottle 13.

Similarly, in Figure 3 the spigot 10 is free to move within the impression 11 until trapped in the left hand apex of the impression 11, at which point both downward and rightward is required to free the spigot 10, and therefore its associated component, from the impression 11. To allow horizontal movement without disengagement, or incorporating a triangular spigot 10 and trap as shown, or a combination of both ideas will make the fastening difficult for infants to open.

In Figure 4 three lugs or spigots 10 align with three scrolls 11 prior to fastening. In this example, however, the spigots 10 are formed on the intrusive or male element, a toothpaste tube 16 whereas the scrolls 11 are formed on the inner face of the female element, a cap 1 7. The action involved for fastening is as described above and since the cap 17 in this application is usually made of a non-rigid plastic material a seal of compressible material is unlikely to be required to locate the spigots 10 tightly against the scrolls 11 when the fastening action is complete.

In Figure 5 the male element of the fastening device is a bolt 18 which has five impressions 11 either formed into it or fashioned in a sleeve 19 and secured to the bolt 18. These impressions 11 align with the five lugs or spigots 10 fashioned on the internal face of a nut 20 which forms the female element of the fastening device. A spring washer 14 is provided to exert an upward pressure on the nut 20 when fastened. As with a conventional nut and bolt, the bolt 18 is inserted through a hole in each item to be joined prior to the addition of the spring washer 14 and the nut 20. Different thicknesses of material can be accommodated by varying depths of sleeve 19 and washer 14. Fastening and loosening will be achieved as described in the above examples.

Figure 6 shows an application where the male member of the device is itself a functional item; in this case a potentiometer 21.

This is fastened to an amplifier chassis 22 by means of a hole in the chassis 22, spring washer 14 and nut 20 as in figure 5.

In Figure 7 two cylindrical components, in this case tubes or pipes 23, both having sleeves 19 with impressions 11 fashioned therein and secured at their ends align and mate with a sleeve 24 of larger diameter having two sets of lugs or spigots 10 formed on its inner surface. This sleeve is shown in cross section to show the internal construction and seals 14 of compressible material.

If required the tubes or pipes 23 could be attached by means of a plug of smaller diameter rather than a sleeve 24 as illustrated using the same principle.

Fastening in both cases is achieved as in earlier examples by a rotary motion.

In Figure 8 a flywheel 25 is located on a shaft 26 by means of a key 27. The shaft 26 has impressions 11 formed upon it or attached by means of a sleeve 19 as in Figure 5. As in earlier examples the flywheel 25 is secured by means of a spring washer 14 and nut 20 having lugs or spigots 10 fashioned on its inner surface which align and mate with the impressions 11 on the shaft 26 when the nut 20 is turned relative to the shaft 26.

Figure 9 shows the application of the fastening device for attaching an object to a flat surface such as a wall. The female element or plug is partially segmented to allow expansion within a drilled hole of appropriate size in the wall. The male element or pin is then inserted through a hole in the item to be fixed (not shown) into the plug so that the spigots 10 align with and lock into the impressions 11 on the internal surface of the plug as in the preceding examples. As the pin nears it limit of penetration the plug is pressed outward due to interference between the pin and its own tapered internal surface, thus securing the plug within the hole in the wall. Variations in thickness of the item to be attached can be accommodated by the natural drawing effect of the pin upon the plug and the provision of washers of differening thicknesses as in Figure 5.

In Figure 10 a conventional woodscrew 28 has been adapted to incorporate the present invention at its head or parallel section of its body. Impressions 11 are formed upon the parallel section of the screw 28 so that when the screw 28 is driven home in the usual way it forms a pin protruding from the wood 29 to which an object can be quickly attached using a spring washer 14 and nut 20 as in earlier examples. Removal of the object from the fastening device is thus facilitated without the time consuming removal of the screw 28 itself. Similarly the device can be incorporated on a nut and bolt or stud.

In Figure 11 a typical 'bayonet fitting' light bulb having two spigots 10 on opposite sides of its base 30 is accepted by the female element of the device or holder 31, the spigots aligning with the impressions or scrolls or cutaways 32 formed in the holder 31 so that when securely attached by rotation as above the contacts 33 on the base 30 align with the contacts 34 within the holder 31. A spring 35 exerts an upward force on the contacts 34 via an insulating mount 36 which retains the light bulb base 30 in the locked position and maintains an electrical connection between the contacts 33 and 34 on the bulb and holder respectively.

Claims

1. A fastening or locating device consisting of a number of lugs or spigots protruding from one of its constituent parts which correspond with impressions or scrolls formed in or attached to another constituent part, such impressions or scrolls being roughly in the form of a tick ('/) handed either right or left together with such washer or seal as is necessary to retain the spigots tightly in the closed position.

2. A fastening device as claimed in Claim 1 wherein location in a certain plane or direction is provided by uneven spacing of the spigots or lugs and impressions or scrolls.

3. A fastening device as claimed in Claim 1 or Claim 2 wherein horizontal motion is allowed while in the closed position by the adaptation of the shape of the impressions in order to provide a seal proof against tampering.

4. A fastening device as claimed in Claim 1, Claim 2 or Claim 3 wherein lugs or spigots of triangular section are used in combination with a trap of triangular shape made by adaptation of the shape of the impressions in order to provide a seal proof against tampering.

5. A fastening device as claimed in any of the preceding Claims wherein the lower face of the impression does not continue directly to the upper surface of the object in which it is formed but continues roughly level to such upper face making a cutaway therein to facilitate location of the other element, thus altering the basic shape from that of a tick ('/) to that of a 'square root' sign.

6. A fastening device as claimed in any of the preceding Claims applied to the fastening of a lid, top or cap to a bottle, tube, tin, jar or such like container.

7. A fastening device as claimed in Claim 1, Claim 2, Claim 3, Claim 4 or Claim 5 capable of being used to replace a nut and bolt or stud as a means of attachment.

8 A fastening device as claimed in Claim 1 Claim 2 Claim 3, Claim 4 or Claim 5 one element of which is formed on or attached to a component which requires fastening to another component forming part of a larger assembly, the other element being incorporated in a nut or in such other component.

9. A fastening device as claimed in Claim 1, Claim 2, Claim 3, Claim 4 or Claim 5 wherein two cylindrical components each incorporating one element of the device may be secured or located by a close fitting sleeve or plug incorporating the two complementary elements on its respective inner or outer surface.

10. A fastening device as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5 or Claim 8 by means of which a flywheel sprocket, oilseal or like component may be located or fastened on a shaft,

11. A fastening device as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5 or Claim 8 wherein one of the two elements of the device requires to be sunk into a solid object such as timber or masonry to facilitate attachment of another object to such plane surface.

12. A fastening device as claimed in Claim 1, Claim 2, Caim 3, Claim 4 or Claim 5 wherein the impressions or scrolls or lugs or spigots are formed on the parallel section of a conventional screw or bolt, to which the attachment of a third component or object is desired.

13. A fastening device as claimed in Claim 1, Claim 2, Claim 3, Claim 4, Claim 5 or Claim 8 capable of accepting an existing product, e.g. a 'bayonet fitting' light bulb as one of its elements or wherein the compressible material which exerts the force required to locate the spigots within the device is in the form of a spring.