GB2470550A

GB2470550A - Adjusting Device Comprising Flexible Member with Indicia .

Info

Publication number: GB2470550A
Application number: GB0908584A
Authority: GB
Inventors: Alexander Burnup
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-05-19
Filing date: 2009-05-19
Publication date: 2010-12-01
Also published as: GB0908584D0; WO2010133874A1

Abstract

An adjusting device for making fine adjustments to a piece of apparatus, in particular an optical device such as a range finder, telescopic sight or dioptre sight. A rotary adjustor such as a control knob 16 has a cylindrical surface 22 onto which can be wound a flexible member such as a tape 20 carrying indicia 34. The adjustor has a fitting (Figure 1,13) to engage a rotatable adjusting member of the telescopic sight or other device to which the adjusting device is fitted. Indicia 34 are provided along the length of the flexible member, which is sufficiently long to require multiple turns of the adjustor 16 to display all the indicia, which thus indicate the rotational position of the rotary adjustor and the number of turns made. This makes it easier for a user to keep track of adjustments made to the device. The device may be in the form of a cassette comprising a rotating adjustment knob and a reel of indicator tape 35 with one end of the indicator tape being secured to the cylindrical surface 22 of the adjustment knob.

Description

ADJUSTING DEVICE

This invention relates to a device for making fine adjustments to a piece of apparatus, particularly apparatus in which such adjustments are made by rotating a knob or spindle, for example a range finding device, telescopic sight or dioptre sight.

A sighting device such as a telescopic sight, as used for example on a rifle, typically has knobs mounted on screw threads to make very fine adjustments for distance and/or "windage". The former makes vertical adjustments of the sight so that the elevation at which a bullet is fired is increased to compensate for increased distance, and the latter makes horizontal adjustments to allow for the speed and direction of the wind. These knobs are typically mounted on spindles with ball catches that allow each knob to be rotated in small angular steps, clicking into position with each adjustment.

A problem that arises with devices of this type is that fine adjustments may need to be made over a wide range, necessitating several turns of the adjustment knob so that it is easy to lose track of where the adjustment has reached. Indicia may be provided on the adjustment knob, but it is difficult to provide much information around a small adjusting knob.

On one type of adjusting knob, mounted on a screw thread so that the knob moves slightly along the axis of rotation as it turns, indicia may be provided around the circumference of the knob and also on a shaft on which the knob is mounted, so that an edge of the knob exposes more indicia with each turn.

Nonetheless, there is a need for an adjusting device which can hold and display increased amounts of information over both small and large adjustments.

The present invention provides an adjusting device comprising a rotatable adjustor for connection to a piece of apparatus to make adjustments thereto by rotation of the adjustor, the adjusting device further comprising an elongate

I

flexible member, a part of which passes around a surface of the adjustor and is constrained to move therewith as the adjustor is rotated, said flexible member having indicia thereon along its length and having a length greater than the circumference of the surface of the adjustor around which it passes, whereby more than one rotation of the adjustor is required to display all the indicia along the length of the flexible member.

The adjustor is preferably in the form of a rotatable knob, arranged to rotate a cylindrical surface around which the flexible member passes. The cylindrical surface of the adjustor may be formed on a spool or drum at one end of the knob and coaxial therewith. The flexible member should be substantially non-stretchable and is preferably in the form of a tape, with indicia on one or both sides. Although only the indicia on one side will normally be displayed, a tape could be reversible and carry a second set of indicia on his opposite side, for different functions or to adapt the tape to different devices. The flexible member preferably has a length that is several times the circumference of the surface of the adjustor around which it winds. For use with an adjusting knob with an adjustment range corresponding to n turns of the knob, the length of the flexible member should be at least nc, where c is the circumference of the cylindrical surface n will typically be from 4 to 10, preferably 6 to 7. The knob or drum may have a fitting at one end to engage the device to be adjusted. The fitting may for example comprise a recess with a splined or non-circular cross-section.

One end of the flexible member may be secured to the surface of the adjustor so as to be wound onto or off the surface depending on the direction in which the adjustor is rotated. The flexible member preferably passes to the adjustor from a reel around which the rest of it is wound, the reel preferably being provided with a rewind mechanism, to wind up the tape as it leaves the adjustor.

Instead of a tape, the flexible member could for example be in the form of a toothed belt, to avoid possible slippage.

The adjusting device of the invention may suitably be in the form of a cassette comprising a rotating adjustment knob and a reel of indicator tape, one end of the tape being secured to a cylindrical surface of the adjustment knob, whereby rotation of the knob in one direction causes tape to be drawn from the reel and wound onto the cylindrical surface of the knob. The reel preferably has a return spring so that when the knob is rotated in a direction to unwind the tape, the tape is wound back onto the reel.

The adjusting device of the present invention is particularly suitable for making fine adjustments for example to optical devices such as telescopic sights.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing wherein: Figure 1 is a perspective view from below of an adjusting device according to the present invention; Figure 2 is an exploded view from above of the components of the device of Figure 1; Figure 3 shows the components of Figure 2 assembled, without the top cover; Figure 4 is a perspective view of two adjusting devices according to the present invention mounted on a bracket for securing to a telescopic sight; Figure 5 shows the assembly of Figure 4 mounted on a telescopic sight; Figure 6 is a perspective view from the opposite side of the assembly of Figure 5; Figure 7 is an enlarged perspective view of the bracket used in the assembly of Figures 5 and 6; and Figure 8 is a partially cut away view showing the mounting of the bracket of Figure 7 on a rifle sight, without the adjusting devices in position.

Referring first to Figures 1 to 3, an adjusting device generally indicated by in Figure 1 comprises a cassette formed of a main housing 12 and friction-fitted cover 11. On the underside of the main housing 12 is a dovetail fitting 14 for securing the housing in position on a device to be adjusted, as will be described later.

The device further comprises a rotary adjustment knob 16 having parallel splines 18 formed around its circumference for enhanced grip. Coaxial with the knob 16 is a cylindrical winding surface 22 between annular flanges 19.

A flexible, non-stretchable tape 20 is arranged to unwind from a reel 35 onto the winding surface 22, the leading end 32 being fixed to the surface 22.

The tape has a width such as to enable it fit neatly between annular flanges 19.

The knob 16 has at its lower end a cylindrical flange 17 projecting axially from the underside of the lower flange 19, to fit snugly into a circular aperture 21 in the underside of housing 12, so that the lower flange 19 rests on the bottom of the housing. The lid 11 has a similarly dimensioned circular aperture 37 to fit over the upper part of the knob 16. The knob can thus rotate freely in the housing.

As can be seen in Figure 1, at least the lower part of the knob 16 is hollow, with splines 13 parallel to the axis of rotation of the knob, to engage a knob of the device to be adjusted, as will be described below, so that the knob thus engaged will be constrained to rotate with the knob 16.

The tape 20 has indicia such as 34 along one side, this being the side facing inwards on the part of the tape coiled into a reel 35, but outwards when the tape is wound around cylindrical surface 22. The housing 12 has a window at the end adjacent to the knob 16, so that the indicia on the tape wound around the surface 22 can be seen. A magnifying panel could be provided in the window 15.

The assembly of the device will now be described in more detail with reference to Figures 2 and 3. As shown in Figure 3, the reel of tape 20 is wound onto a spool 25, between annular flanges 23 similar to the flanges 19 on knobs 16. The spool 25 fits into the housing 12 around a central split post 24, integral with the housing.

A torsion spring 27 fits within spool 25 and has an inner flange 28 which fits in the split post 24 SO as to be held against rotation. The outer end 29 of the spring fits into a slot 26 of the spool 25, so that rotation of the spool causes the spring 27 to coil more tightly, biasing the spool in the opposite rotational direction.

Rotation of the knob 16 in an anticlockwise direction as seen in Figures 2 and 3 causes the tape 20 to be drawn off the reel 35 and wound onto the cylindrical surface 22. The inner end of the tape reel 35 is secured to the spool 25, so that as the tape is unwound from the spool 25 the spool is caused to rotate in a clockwise direction against the force of spring 27. Thus, rotating the knob 16 in a clockwise direction allows the tape 20 to wind back onto the spool 25, the spool rotating in an anticlockwise direction under the force of spring 27 to wind the tape back onto it.

The spring 27 is strong enough to wind the tape back onto the spool 25 as it is unwound from knob 16, but not strong enough to rewind the tape unless the knob 16 is deliberately rotated. In use the knob 16 is engaging a rotatable part of the device being adjusted, which is generally provided with a detent such as a ball catch, enabling it to hold its rotational position until deliberately turned.

As the knob 16 is turned, the indicia on the tape surface pass the window 15, enabling the precise rotation position of the device being turned by the knob to be displayed. Because the tape is several times longer than the circumference of the cylindrical surface 22, the indicia displayed in the window 15 can be used not only to indicate the rotational position of the knob relative to the housing, but to count multiple rotations of the knob.

Figures 4 to 7 show how two adjusting devices 10, 30 can be fixed to a telescopic sight 40. The two devices are secured at right angles to one another by means of a bracket 60, shown in detail in Figure 7. The bracket comprises a main body 61 on which are formed dovetail channels 62, 63 at right angles to one another on the outer surface of the main body, to accommodate corresponding dovetail fittings 14 of the undersides of the two adjusting devices.

Hingedly attached to the main body 61 is a closure member 64, rotatable relative to the main body 61 about an axis extending between bolts 65 which secure the closure member 64 to the main body. The main body and the closure member define between them an opening 66 through which the barrel 40 of a telescopic sight 50 can extend (Figures 5 and 6). The closure member 64 can be opened by releasing bolts 68 and then clamped around the barrel of the sight and secured it.

Figure 8 shows the position of mounting the bracket 60 on the barrel 40 of the sight 50, in relation to adjusting knobs 70, 75 which are positioned about midway between the objective end 45 and the eyepiece 48 of the sight. The adjustment knobs 70 and 75 are positioned perpendicular to one another to rotate about mutually orthogonal axis. One of these knobs is arranged to adjust the elevation of the sight according to the distance of the target while the other is arranged to make horizontal adjustments to compensate for windage. Each of these knobs is mounted in a ball-catch detent (not shown) for stepped rotation so that small fixed adjustments can be made. Because the range of adjustment, particularly for distance, is very wide, each of the knobs 70, 75 can rotate several times in order to cover the full range of available adjustments. The adjustment device of the present invention is intended to assist the user in keeping track of the adjustments made.

To fit the adjustment devices in the positions shown in Figures 5 and 6, a device such as 30 is positioned with the hollow underside of knob 16 over the knob 75 so that the splines 30 engage with corresponding formations around the periphery of the knob. It will be noted that the dovetail slots 62, 63 curve towards the knobs 75, 70 respectively, the radius of curvature of each slot corresponding to the distance between the centre line of the slot and the axis of rotation of the respective knob, so that when the adjustment device is placed over one of the knobs it can be rotated clockwise until the dovetail formation on its underside engages in the slot 62 or 63. Further rotation fixes the device in position. If the device is fitted when the corresponding knob 70 or 75 is at an extreme position, and the indicator tape 20 of the adjustment device is wound fully onto its spool 25, the figure displayed in the window 15 will be that corresponding to one end of the adjustment range of the knob. As the knob 16 of one of the devices 10, 30 is rotated, the knob over which it is fitted will turn with it and the precise position of that knob will be displayed in the window 15.

Because a bullet fired from a rifle travels in a parabolic path, the elevation adjustment of the sight will itself be not on a linear scale but on a parabolic one.

When focusing on long distances, therefore, more turns of the adjustment knob are required and more of the tape 20 will pass behind window 15. Thus, the amount of information that can be displayed on the tape will be greater the longer the range over which the gun is being fired. For example, the indicia corresponding to each five or 10 metres of range will be spaced further apart when focusing at the far end of the range, and more indicia can be included between them.

The device of the invention may be made of any suitable material. The housing may for example be made of a rigid plastics material such as polypropylene or glass fibre reinforced plastics, but could also be made for example from steel or aluminium. The tape 20 may be made from a plastics tape but could also be made of thin metal or with a fibrous matrix to minimise stretching.

While the device of the invention has been illustrated with a tape the flexible member could for example include a wire to increase strength and minimise stretching.

While the device of the invention has been illustrated for use with a telescopic sight, it will be appreciated that it could equally well be used on other devices such as optical range finders or valves which require adjustment over a wide range and where the indicia that can fit on or around an adjusting knob are limited. The device may be made, as illustrated, as a separate unit for fitting to the device to be adjusted, or could be incorporated in the device itself.

Claims

CLAIMS1. An adjusting device comprising a rotatably mounted adjustor for connection to a piece of apparatus to make adjustments thereto by rotation of the adjustor, the adjusting device further comprising an elongate flexible member, a part of which passes around a surface of the adjustor and is constrained to move therewith as the adjustor is rotated, said flexible member having indicia thereon along its length and having a length greater than the circumference of the surface of the adjustor around which it passes, whereby more than one rotation of the adjustor is required to display all the indicia along the length of the flexible member.
2. An adjusting device according to claim I wherein the adjustor is in the form of a rotatable knob arranged to rotate a cylindrical surface around which the flexible member passes.
3. An adjusting device according to claim 2 wherein the cylindrical surface is formed on a drum or spool at one end of the knob and coaxial therewith.
4. An adjusting device according to claim 3 wherein the knob or the drum has a fitting at one axial end thereof to engage a rotatable element of a device to be adjusted.
5. An adjusting device according to any preceding claim wherein the flexible member is in the form of a tape, with said indicia on one side thereof.
6. An adjusting device according to any preceding claim wherein one end of the flexible member is secured relative to the surface of the adjustor around which it passes, so as to be wound onto or off the surface depending on the direction in which the adjustor is rotated.
7. An adjusting device according to any preceding claim wherein the flexible member is wound onto a reel spaced from the adjustor and is drawn onto the adjustor from the reel when the adjustor is rotated.
8. An adjusting device according to claim 7 wherein said reel is provided with a rewind mechanism to wind up the flexible member as it leaves the adjustor.
9. An adjusting device according to any preceding claim in the form of a cassette comprising a rotating adjustment knob and a reel of indicator tape, one end of the tape being secured to a cylindrical surface of the adjustment knob, whereby rotation of the knob in one direction causes the tape to be drawn from the wheel and wound onto the cylindrical surface of the knob, while rotation of the knob in the opposite direction causes the tape to be wound back onto the reel.
10. A device according to claim 9 wherein the cassette comprises a housing with a window therein through which indicia on the tape can be viewed.
11. An optical device having a rotatable adjusting member for adjusting the device, wherein said rotatable adjusting member is engaged by, and arranged to rotate with, the rotatable adjustor of an adjusting device according to any preceding claim.
12. An optical device according to claim 11 in the form of a telescopic sight.