GB2130671A - Cylindrical sinusform transmissions - Google Patents

Abstract

A Sinusform wheel has on its circumference an endless sinusoidal groove or track which is comprised of inflecting arcs of 180 DEG each. Two adjacent arcs total 360 DEG or one Sinusform revolution, 1 S.R. In Fig. 6, when the small 4 S.R. wheel is rotated the motion is reproduced in the larger 8 S.R. wheel via two rotatable pins in a single housing which reciprocates in a slotted guide. In Fig. 7 the motion of the 4 S.R. wheel is reproduced via oscillating links. Adjustable arms (A)(B) are locked to a non-slip spacer (S) which pivots on pin (P). The secondary, independent set of arms ensure direction control of the driven 8 S.R. wheel, by being slightly offset from the track position of the primary set of arms. Motion is transmitted at a ratio of 2 to 1. <IMAGE>

Description

SPECIFICATION The application of sinusform to cylindrical sinusoidal track transmissions A Cylindrical Sinusoidal Track Transmission is a means of converting rotary motion into reciprocating motion and back into rotary motion at any required ratio.

Sinusform, when applied to a mechanical workpiece, though similar in operation to a cam, has been so named to distinguish it from a cam. It is the purpose of this text to indicate the difference.

Sinusform, in its cylindrical application is that wherein arcs of 1800 alternate at the point of inflection, the gradient of which is at 90" to a straight line connecting the arc vertices, as indicated in Fig. 1.

Fig. 2 shows a Sinusoidal track or groove, of square cross section, in which a rotatable pin is positioned. If the pin is moved from position 'A' to position 'B' it will have moved through 3600 of the Sinusform, or completed one Geometrical revolution or, pertinently, one Sinusform revolution, 1 S.R.

When the rotatable pin is restricted to linear motion parallel to the 900 gradient, represented in Fig. 2 as the dotted line, CD, then the Sinusform will have moved at right angles to the gradient.

Similarly, if the pin is restricted to an oscillating motion, from C to D and D to C, then the Sinusform track will move at right angles to CD in ratio to the arc of oscillation, i.e. slow, with a iarge radius, and relatively faster with a small radius.

It must be stressed at this point, that a rotatable pin, moving through a Sinusform track, is moving in perfect arcs, and that once the pin has passed the geometrical point of inflection, it has merely changed its relative arc and is constantly equidistant from the arc vertex, unlike a cam which is defined as an irregular shape that is rotatable.

If, in the foregoing explanation, the word gradient is unsuitable, then substitute the phrase 'common tangent'.

A Sinusform track is machined in the circumference of a cylinder and any motion imparted to that Sinusform, whether it be motivated by reciprocation or oscillation of the rotary pin, will be rotation around the cylinder axis if the cylinder is restricted to that motion only.

For the purpose of this text a cylinder with a sinusoidal track or groove in its circumference will be referred to as a Sinusform wheel. Sinusform wheels will be distinguished by the number of Sinusform revolutions in their tracks, i.e. a 4 S.R.

wheel will have a track consisting of 8 alternating or inflecting arcs, of 1800 each, encircling the circumference of the wheel.

A distinguishing feature of Sinusform is that it is generated by three simultaneous motions of the cylinder. These motions are, two rotary motions and one laterally linear motion.

As represented in Fig. 4, the cylinder rotates on its axis 'A', and on the 'Y' axis of the cylinder cross section at the Sinusform centre line.

The lateral linear motion is in the plane of the 'X' axis and parallel, in direction, to the 'X' axis.

The length of the linear motion must equal the radius of the Sinusform arc.

The rotation of the cylinder around the 'Y' axis must equal 900 from start to finish of the linear 'X' axis orientated motion. Simultaneously, the rotation of the cylinder around its 'A' axis must equal: 3600 No. of S.R.x4 3600 i.e. 4 S.R. wheel= =2221.

16 The motions described will have completed one quarter of a Sinusform revolution.

If, as in Fig. 3, motion is imparted to pin 'R', the direction of rotation is entirely dependent upon the position of the pin in the Sinusform track whilst it is inert, i.e. before or after Top Dead Centre of the Sinusform arc, as in the similar circumstance of an l.C. Engine connecting rod and crankpin.

Therefore it is imperative, if direction control is required, that another pin, of independent function, be added to the Sinusform wheel to ensure that at any instance, no two pins will be at Top or Bottom Dead Centre positions simultaneously.

The same rules apply to both reciprocating and oscillating pins.

The simple housing and pin illustrated in Fig. 3 can be used for direct connection to another Sinusform wheel, or to a connecting rod on the protruding part of the pin, for remote transfer of motion.

In Fig. 3, the rotatable pin 'P' in its housing 'H' reciprocates in the slot in guide 'G'.

In Fig. 2 the points indicated by the letters 'A' and 'B' and the centre of the position held by pin 'P', are the distances between guide slots that must be avoided to achieve direction control, i.e.

the distance between the parallel guide slots must be more, or less, that the distances between points of inflection.

Any two pins whose positions equated these distances would reach Top and Bottom Dead Centre positions simultaneously.

For Sinusform wheels in close proximity, one superimposed, a single guide, with two independent, parallel slots can be used providing that the pins are aligned parallel to the radii, as in Fig. 5.

An instance wherein wheels in close proximity are aligned axially showing the need for a longer type of guide is shown in Fig. 6. An example of the transfer of rotary motion via oscillating links and pins is shown in Fig. 7, whereby the wheels can be repositioned, through the arc of a reflex angle, in the plane of their axes.

The independently movable arms 'A' and 'B' are positioned to suit the wheels, then locked together to operate in unison.

The secondary set of arms are for the purpose of direction control and they must have an independent pivot, 'P', in Fig. 7, to allow direction control adjustment.

The spacer, 'S, in Fig. 7 is needed only in the circumstance of different wheel diameters.

An axially remote transmission can be achieved, in the use of reciprocating pins, by merely connecting the pins with a rod of suitable length, but where a change in the direction of the reciprocating stroke is needed, a guide of the type illustrated in Fig. 8 is required.

This example is, in effect, two guides, G, at right angles to each other and where the rotatable pins are connected by a link, 'L', in Figs. 8 and 9.

The letter 'H' denotes an access hole to allow a connecting rod to be screwed directly into the pin housing which is identified by the letter 'A' in Fig.

9 and whose profiie is outlined by the dotted line.

'B' is a spacer between the guides. The spacer 'C' allows the housing to be reversed independently.

Following is a brief index of the drawings.

Fig. 3. This is of a 4 S.R. Sinuswheel, S, a rotatable pin, R, and a pin housing, H. The housing reciprocates in a slit in guide G.

In Fig. 4, A is the cylinder axis, X and Y are the geometrical axes of a cross section of the Sinusform cylinder.

Fig. 5 is a frontal view of two diametrically opposed Sinuswheels in close proximity. The cross section of the double slotted quide, G, is taken at a point where the two reciprocating housings, A, are in line. The housings are split for easy assembly.

Fig. 6 denotes two, axially aligned, Sinuswheels, the smallest of 4 S.R. and the larger of 8 S.R. The cross section of the guide, G, is taken in the centre of one of the two parallel slots, and the centre of one of the housings, A. Here again, the housings are split to allow assembly in the guide. Bolt hole E, allows the addition of a steadying bracket.

Fig. 7 depicts a pair of oscillating arms, A and B, which are locked to a non slip, serrated edge spacer, S. These spacers are only necessary where the Sinuswheels are of different diameters.

The pivot, P, is independent from the pivot in the other pair of arms to allow separate adjustment of one pair of arms for direction control of the driven Sinuswheel.

Fig. 8. This is the plan view of an angle guide for two diametrically opposed Sinuswheels which are remote from each other.

The function is to change the axial linear stroke of the pins to a diametrical stroke.

Various angles can be achieved with the same guides by merely altering the angle of the secondary guide and substituting a link of the appropriate length.

In Fig. 8, G is the primary guide, L the link and H is the access for a connecting rod.

Fig. 9 is a side view of the guide in Fig. 8. B is the spacer between the primary and secondary guides, and C is a spacer which allows the reversal of the secondary guide housing A. L, the link, A again denotes the primary slot housing.

It will be evident that by various combinations of Sinuswheels, guides, and, or, oscillating links, a fully universal drive can be accomplished. For stronger drives, or transmissions, more pins and guides can be added to the wheels. The foregoing examples of Sinusform track have all been of square cross section.

Numerous cross section forms can be used such as half round or tapered. Larger track, than the examples given here, is quite feasible.

Claims (1)

1. Claims

   1. Any wheel, shaft or cylinder, having on it's circumference, an endless groove or abutment which is shaped in conformity with the geometrical principle of Sinusform.

   2. The use of two, or more, oscillating or reciprocating links in conjunction with two or more Sinusform wheels, shafts or cylinders as identified in Claim 1.

   3. The application of double slotted guides (Fig.

   5) and (Fig. 6) to Sinusform wheels, shafts or cylinders as in Claim 1.

   4. The application of single slotted guides (Fig.

   8) for use in conjunction with mechanisms described in claims 1, 2 and 3.

   5. The use of different diameter wheels having different numbers of Sinusform revolutions (S.R.) on their circumference for the transmission of motion at various ratios.