GB2116661A - Improvements relating to dowel like pins - Google Patents

Abstract

This is a dowel pin suitable for easy driving into members to be pinned together. The pin has a longitudinal bore (22) and at least two external helical flanges (21), and may have internal helical projections (23). Lengths of such dowel can be used as a writing implement, as a projectile, as a heat- exchanger, in a lamp (Figure 5), in a paint-sprayer, in a simple jet-engine, as a drilling tool, as a structural component, or as a decorative device. <IMAGE>

Description

SPECIFICATION Improvements relating to dowel like pins British Patent Specification No. 8129534 describes and claims dowel like pins with a cross section consisting of a core having two or more protruding helical flanges running parallel with each other along the length of the core, the core having a longitudinal bore.

An object of the present invention is to use such a dowel like pin in a numberofapplications otherthan applications where a dowel pin would normally be used.

The pin may have a number of internal projections along the bore, and they may be of helical form preferably corresponding with the helical form ofthe flange, sothatthecomplete pin can beformed by twisting an extruded section with straight flanges and projections.

There may be an end memberfitted into the bore in the core at one or each end of the pin. For example a writing implement could have a closure gap fitted into one end ofthe bore and a writing head or nib fitted into the other end. Again if the pin was to be used as the body or shaft of an arrow, then a point could be fitted into one end of the bore and a head having aslotfora bowstring could befitted into the other end.

The outer edges oftheflanges or the inner edges of internal projections, or both, can be of enlarged form to provide a good heat exchange surface or a good bearing surface.

Thus, there may be a cylindrical memberwithin bore located by the inner ends of the projections, and that could be rotatable. If it is in the form of a tube, then the bore within thattube could be used for supplying a fluid along the pin, and where two fluids are to be mixed, for example, in a fuel burner or a paint spray, one fluid for example, fuel, or paint, could be drawn along such a bore, while airfor combustion orfor atomising the paint could be drawn along the bores within the longitudinal bore but surrounding the innertube. The helical form of the projections can cause air to swirl as it passes along the longitudinal bore.

There may be a cylindrical tube surrounding the pin and it could perhaps be fixed to the edges of the flanges, ortheflanged core could be arranged to rotate in such a cylindrical tube and there has also been a suggestion for using the pin with an internal tube in afuel burning lamp orin a paint sprayer. It would also be possible to use such a device as a blow torch.

Another possibility is to have an internal body in the form of a cylindrical mesh filter which could collect condensate from wet gas flowing along the longitudinal bore to leave dried gas passing along outside the filter, and within the inner surface ofthe longitudinal bore.

The protruding helical flanges will cause air passing along the outside surface ofthe pin to be given a swirling motion, which will be useful in a number of applications, for example for supplying airforcombustion purposes.

Another possibility is the use of such a device as a part of a jet engine with combustion fuel ejected from the longitudinal bore into the space between the external flanges and the surrounding cylinder, so that the products of combustion acting on the helical flanges cause relative rotation between the cylinder and the flanged pin.

Again the pin with orwithoutthe surrounding sleeve could be used as the stem or shank of a drilling device so that the action of the helical flanges can be used to remove dust generated in the drilling process.

The external sleeve could be used as a bore liner to be left in position after drilling has been completed.

The invention may be carried into practice in various ways and certain embodiments will now be described by way of example with reference to the accompanying drawings, in which:~ FIGURE 1 is a copy of FIGURE 1 of British Patent Specification No.8129534 (Case 5); FIGURE 2 is a view corresponding to FIGURE 1 showing one modification in accordance with the present invention; FIGURE 3 is another view corresponding to FIGURE 1 showing more modifications according to the present invention; FIGURE 4 is another variant of FIGURE 1 showing a furthermodification in accordance with the present invention; and FIGURE 5 is a diagrammatic elevation of a device which may have a cross section as shown in any of the FIGURES 1-4.

Itwill be remembered that specification No.

8129534 discloses a dowel pin with a core having two or more protruding helical flanges running parallel with each other along the length of the core, the core having a longitudinal bore. That specification also describes some uses of such a dowel pin which uses can be generally described as methods of achieving fixtures. There is also a reference to British Patent Specification No. 1233175 which is for a dowel pin which does not have a longitudinal bore.

It has since been discovered that a dowel pin with a longitudinal bore can be used either in the manner disclosed in Specification No.8129534, or with some modifications in a number of different applications and those applications are the subject of this patent specification.

First of all some of the modifications to the dowel pin shown in Specification No. 8129534 will be described.

FIGURE 1 shows in solid lines the cross section of a dowel pin as shown in FIGURE 1 of that specification.

The section consists of a cylinder 20, having six equally circumferentially spaced external helical flanges 21, and a central longitudinal bore 22 having a number of internal projections 23, each one being opposite an external flange 21. An extruded tube of constant cross section is twisted so that both the flanges 21 and the projections 23 lie along corres The drawings originally filed were informal and the print here reproduced is taken from a later filed formal copy. ponding helical lines. The pitch of the helix will depend upon the particular application of the pin.

FIGURE 1 shows in chain lines at 24 how the outer edge oftheflanges 21 can be enlarged to provide an external surface which is fairly large, for example for heat conduction with the atmosphere, and which also has rounded edges so that the sharp edges ofthe simple flanges 21 are avoided.

Atubularmemberwith a section as shown in FIGURE 1 and with orwithoutthe enlarged portions 24 can be used as a component of a heat exchanger, or a heater or cooler, with a fluid being passed through the longitudinal hole 22 with heat exchange tothesurrounding airincontactwiththeouter surface of the tube 20 and the surfaces of the flanges 21 which air is arranged to swirl by virtue ofthe helical form of the flanges 21. The inner projections 23 assist in heattransferbetweenthefluid and the' all ofthe tubular member.

The pitch ofthe helix, the numberofflanges, and the radial length of the flanges can ail be designed in accordance with the heat transfer effect to be achieved.

FIGURE 2 shows howwiththetubular pin of FIGURE 1 a closed ended cylindrical shell mesh filter 25 can befitted in the bore just within the projections 23 to collect condensate from wet gas being passed along the tube, so that there is a freerflow of gas from which condensate has been extracted in the spaces 26 between adjacent projections 23 and outside the filter 25.

FIGURE 3 shows how an internal tube 27 can be fitted within the tips of the projections 23, and that could for example be used as a capilliarytube forming a component of a ballpoint pen, and acting as an ink reservoir. The flanges 21 give the pen a good external fingergrip, and also at each end provide respectively a secure seating for a closure cap and a clip, and for a writing head or nib.

The projections 23 could be enlarged at the inner ends oftheir sections, as shown at 28, to provide a larger bearing surface for the outside of the tube 27.

The tube 27 could also be formed with one or more external flanges 29 (one only is shown in FIGURE 3) with a helical form conforming with that of the spaces 26 between adjacent projections 23, so that by relative twisting ofthe tubular pin 20 and the tube 27, the end of the pen can be projected and withdrawn into the tube 20.

Apartfrom the use as a propelling writing instrument, as described above, such an arrangement in which the innertube 27 has one or more external helical projections 29, can be used in any application where a rotary movement is to be translated into an axial movement, orvice-versa. Rotation of eithertube in relation to the other can produce axial movement of the other, and that is an arrangement in which a wheel could be mounted on one orothertubewith means for providing a linear drive to the other. It is to be noted that in that application the inner tube 27 could be solid.

External grooves 31 in the inner surface ofthetube 20 between the inner projections 23, can constitute lubricant channels in an application ofthat kind, or indeed the external projections 29 could perhaps be rounded off at their corners, or otherwise formed to leave space from the innersurface of the external tube 20 for lubricant. The size of such lubricating channels can be such as to promote capillary action in forcing lubricant along the channels.

The spaces 26 between the inner and outer tubes (the innertube 27 could be solid) or even the space within the innertube 27 could be used to supply liquid fuel to a lamp and act as a sort of non-combustible wick which will continue to burn even if the level of liquid fuel in the reservoirfalls.

Where the member 27 is a tube, it can be arranged to supply liquid fuel of a different flash point from that conveyed by the capilliary channels 26, so that the fuel with the lowerflash point can be used for igniting the lamp, and then when ignition has started, the fuel of higherflash point can be preheated by conduction from the surfaces of the member 27. If for example the inner member 27 contains a small charge of lower fiashpoint fluid for starting ignition, it can be closed off at the bottom while the outertube 20 extends a greaterdistancetothe reservoirforthemain fuel.

FIG U RE 4 shows how a tu bu la r mem ber with a cross section as shown in FIGURE 1 can be a fit in an outertube 33 whether or not the tubular member 20 has an inner component, for example as shown at 25 in FIGURE 2, or at 27 in FIGURE 3, and this outer tube 33 gives a rise to further possibilities.

Where a fuel is supplied along the bore 22, for exampleforalampasdescribedwith reference to FIGURE 3, then the helical flanges 21 within the outer tube 33 which can be open at one end, can cause air drawn in to support combustion at the end of the tube 20 to swirl and provide good mixing and efficient combustion at the flame. Instead of air merely being drawn in through an short open-ended tube 33, air can be supplied under pressure along a surrounding tube 33 extending along the whole length of the tube 27.

FIGURE 5 shows how thetube with a section as shown in FIGURE 4 can be used with a lamp. The main fuel, e.g. paraffin could be supplied from a reservoir 41 along the central bore 22 and can burn in air drawn in through a surrounding sleeve 42. For pre-heating the tube 20, and hence the paraffin, a second- more-easily ignited-fuel, e.g. methylated spirit can be drawn along the spaces 35 between the tubes 20 and 33. As fuel is consumed it may be necessary to raise the reservoir41 to maintain a steady flame, or capilliary action in the bores may be supplied.

In another possibility, the sleeve 42 is omitted and fuel and air are delivered along the passages 22 and 35.

Another possibility isto have radial bores, for example as indicated at 34in FIGURE4 through the wall of the tube 20 at a certain distance along its length, and then fuel passing along the bore 22 can pass radially through the bores 34for combustion in the air space 35 within the tube 33 and outside the tube 20.

The products of combustion will be forced to escape axially, and the helical form ofthe flanges 21 can then cause rotation ofthetwo components, and that can form the basis of a simpleturbojetengine, for example for model aircraft. The tubes 20 and 33 will of course be designed for easy rotation in relation to each other.

Another application of the idea offorcing a fluid along one or other of the longitudinal bores, is that of a paint sprayer, according to which paint can be passed along a central bore while air is caused to flow along the bores bounded by the helical flanges 21 so thattheswirling aircan breakupthe paint into droplets, and provide a directed jet for directing the droplets of paint onto the surface to be painted.

Atubewith a cross section as shown in FIGURE 1 could be used as the shaft of a drilling device with the flutes of the drill in communication with the spaces 35 between the helical flanges 21, and then as the shaft rotates the flanges 21 will lift out dust formed in the drilling operation. Compressed air could be delivered along the longitudinal bore 22 to assist in moving such dust. Such a rotating shaft 20 could be surrounded just outside the hole by a tube as shown at33 in FIGURE4which could be held to directthe drilling process, although it is equally possible to have a rigid shaft with a section as shown at 20 rotated directly by an electric drill.

Indeed a tube such as 33 may be supplied around the rotating flanged tube 20. Atube such as 33which is rotatable in relation to the longitudinal member 20 can be used to line a hole being drilled through a material liable to crumble, and left behind when the drilling operation is finished.

A rod or tube with an external section as shown in FIGURE 1, and possibly with a different number of flanges, can be used as the shaft of an arrow, dart, or javelin, so that the helical flanges cause the projectile to rotate in flight. It may be possible with such a projectile to avoid having feathers orfins at the rear for guiding it, or if fins are required, they could perhaps be mounted along the helical flanges.

One possibility is an arrow made from a tube with a section as shown in FIGURE 1, butwhich istwisted only along a part ofthe length, for example, at the rear, and that may enable fins orfeathers to be dispensed with entirely.

In such a case the projectile could be arranged to be propelledthrough a bore of corresponding section in the bow or other propelling instrument, and then rotation will be emparted to the projectile as the helical flanges pass th rough that hole.

The tube with a section as in FIGURE 1 (or any of the other figures) could be large enough in cross-section to be useful as a structural member in scaffolding or as reinforcement in a composite column. A tu be with the dimensions shown in FIGURE 1 could act as a connector in a toy construction kit. In any case, the helical flanges give a very simple way of connecting the ends of the tube to other components by axial drive.

Short lengths of tube could be strung together on a cord as a decorative neckless, perhaps gilded at selected places. A single short length could act with a hairclipasatiecliporthe like.

Claims (15)

1. A pin having a cross section which comprises a core having two or more protruding helical flanges running parallel with each other along the length of the core, the core having a longitudinal bore.

2. A pin as claimed in Claim 1 in which the bore has a number of internal projections.

3. A pin as claimed in Claim 2 in which the internal projections are of helical form.

4. A pin as claimed in any of the preceding claims including an end memberfitted into the bore in the core at one or each end of the pin.

5. A pin as claimed in any one of the preceding claims in which the outer edges of the flanges orthe inner edges of internal projections are of enlarged form.

6. A pin as claimed in any ofthe preceding claims including a cylindrical member within the bore located by the inner edges of the internal projections.

7. A pin as claimed in Claim 6 in which the cylindrical member constitutes a tube.

8. A pin as claimed in Claim 5 or Claim 6 in which the cylindrical member has external projections of helical form corresponding with the form of the internal projections on the pin section.

9. A pin as claimed in any of Claims 1-8 including a tube surrounding the helical flanges on the core.

10. A pin as claimed in Claim 9 in which the pin can rotate in the surrounding tube, or is fixed to the surrounding tube.

11. Awriting instrument, the body of which comprises a pin as claimed in any of Claims 1-8.

12. Afuel burning lamp in which the body is constituted by a pin as claimed in any of Claims 1-10 and in which fuel is arranged to be supplied along the longitudinal bore.

13. A paint sprayer having a body as claimed in any of Claims 1-8.

14. A projectile having a shaftformedfrom a pin as claimed in any of Claims 1-8.

15. An engine having a body as claimed in any of Claims 1-8.