GB2549129A - A tyre cutting machine and a method of separating a tread of a pneumatic tyre from sidewalls of the pneumatic tyre - Google Patents

Abstract

The current invention is for a tyre cutting machine that cuts a tyre from the inside to make a severed tread and two tyre walls. The tyre cutting machine has a tyre support (CA, A, Fig 2), first and second blades (B, B, Fig 4A), a blade movement mechanism and a tyre drive mechanism (W, A, Fig 4A). The blade movement mechanism may be configured to simultaneously move both blades horizontally outwards in response to the tyre support receiving the tyre thereon (B, Fig 4A). The blade movement device may be in the form of a pair of scissors such that a heavier tyre with apply a greater force to the scissors to push the blades into the tyre wall with a larger force. The blade movement mechanism may also be biased to retract partially or fully upon removal of a tyre. The invention may further comprise a vibrator, tread cutter and/or loading mechanism. The invention may also have an arm to aid loading and unloading tyres (CRA, Fig 3). The invention serves to cut tyres which come in a wide variety of sizes without necessarily needing to adjust the cutting machine and so tyres can be loaded in significant numbers, and the machine left to run without intervention (A, Fig 1). This enables high volumes of car tyres to be processed into building materials. The invention also relates to a method for separating the tread of a tyre from its sidewalls, involving providing a tyre to the tyre cutting device of the present invention, engaging an interior of the tyre on the tyre support, moving the first and second blades into engagement with the interior of the tyre and driving the tyre about its rotational axis (generally shown in figures 1-4A).

Description

A TYRE CUTTING MACHINE AND A METHOD OF SEPARATING A TREAD OF A PNEUMATIC TYRE FROM SIDEWALLS OF THE PNEUMATIC TYRE

Tyre treads are used in the making of a hydroponic grass roof, where on a sloping roof they are screwed together in ship-lapped fashion to make a support for turf. Tyre walls are used to make the support for a sprung floor in ecobuildings that seek to avoid the use of concrete, and can even be used to make round windows. Thus all parts of the tyre can be used as building materials.

Cutting vehicle tyres into tread and walls is not a new idea, but hitherto the reason for doing so was to reduce the space taken up by used tyres. Products currently on the market will either strip out the walls, or sever the loop of the tyre tread. There appears to be no machine that does both in an automated fashion.

The principal reason why no such machine exists is that car tyres come in a wide variety of sizes. This means that a machine for stripping walls from the tread and severing the tread would need to make allowance for the tyre’s size in order to be able to manipulate the tyre and apply the cutting blades in the correct place.

There are many ways to process a tyre so that the walls can be removed and the tread severed. The current invention does so in a way that is low-tech so that the machine can be used and serviced in parts of the world where high technology would not be accessible to the majority of the population. By making it cheap and easy to repair the hydroponic grass roof can be built by small builders in places where the need to create a milder microclimate is most pressing.

Because the invention allows a variety of sizes of car tyre to be processed without necessarily needing to adjust the cutting machine, a machine can be designed into which tyres are loaded in significant numbers, and the machine left to run without intervention. This enables high volumes of car tyres to be processed into building materials.

The current invention is for a self-loading machine that cuts the tyre from the inside to make a severed tread and two tyre walls. Various elements may be original, such as loading and centralising the tyre on the cutting head and then applying the cutting blades to the tyre walls from the inside without necessarily adjusting the machine beforehand to take a particular tyre size.

Put simply, the tyres are lined up to await cutting on a ramp. To release a tyre from the queue, there is a pivot under the floor of the ramp, whose blocks protrude to stop first this tyre then that. When its turn comes to be free of the queue, the tyre is made to roll down, bump into an obstruction, and topple sideways onto a cradle, positioned just above the ‘fist’ that is going to cut the tyre. The cradle assembly steadies and centralises the tyre first.

Next a drive wheel above the cradle descends and pressing down on the tyre first makes it rotate, and with continued pressure causes the revolving tyre to sink onto the raised ‘fist’, which is the cutting assembly, so that the tyre is suspended from it, with the fist now inside the tyre.

The raised fist and its elbowed arm are joined to a main column, so that the machine resembles a desert cactus. However, there is a second horizontal arm a couple of feet above the first, the Depression Arm, attached to the top of the cactus column as a sliding attachment to move up and down on a rack and pinion. This upper arm holds the drive wheels, a guillotine and a tread ejection assembly. The cutting head has rollers that support the tyre from the inside, and blades which extend out to meet the tyre walls and cut them, just where the tread and walls meet, so that as the tyre turns the walls start to separate from the tread.

In its low-tech form, this machine can make the tyre revolve and the blades extend by one single action: lowering the heavy drive wheel depression arm onto the top of the tyre. This causes the tyre to rotate, but in addition the force causes the cutting head (the fist) to sink, and by mechanical means, possibly a scissor and wedge design, this sinking movement is converted into the spreading of the blades towards the tyre wall. There are two alternative versions: one using a twisting rod with arms that spread the blades as it turns, and the other, not unlike the scissor principle but horizontal, a diamond that spreads two adjacent corners as the other two are contracted.

With the walls removed, next comes the severing of the circle of tread by a guillotine and its removal by some rollers to a position away from the machine. This is achieved by a guillotine with a circular blade that can slide down the drive wheel arm to snatch the tyre tread and cut it. The roller assembly performs a similar job along the other side of the arm, sliding into position with the guillotine, and effecting the tread’s removal after the lateral guillotine cut is made.

Earlier in the cycle, after the wall cutting was done, one of the walls dropped away, but the other was stuck, looped over the upper arm’ of the raised first. There is a device to eject it, throwing it back over the fist, in effect where the tyre came from. This device is the cradle that first received the tyre when it toppled, and helped to centre it above the fist. At the back of the cradle is a raised ‘crash arm’ to prevent the toppling tyre falling beyond the cradle. It is this hooked arm which later lowers so that it can catch the falling tyre wall, and in the final phase of the cycle, when the machine is returning to the start position, flips up, flinging the wall back over the cutting head.

The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings.

Figure 1 A. Tyres loaded on Ramp, showing the pivot and chock mechanism for releasing them to the Trap. B. Trap seen from above and in profile with a toppling tyre, showing how the projection destabilises the tyre. C. Three stages to toppling showing the ramp as a very narrow edge. In the third picture a shearing force is making the hinge work, thus releasing the tyre D. Detail of the narrow-surfaced trap with a hinge at the bottom and rollers on the top E. An alternative trap, this time with a sloping surface, hinged at the back to release the tyre.

Figure 2 A. Clarification of the y axis (used later in the description), and illustration of a tyre toppling sideways onto the cutting head B. Tyre in position on the cutting head, (note cradle assembly not shown) C. View of ramp and cutting machine from above, illustrating the relation of the trap to the cutting machine and the x axis.

Figure 3 A. A tyre sits centrally on the cradle assembly, and the crash arm is in the raised position. Dotted lines indicate the lower position for the crash arm. The cutting head is narrow enough to fit between the tyre rims when the cradle assembly is lowered. The cradle assembly is connected to the cutting head support plate at the bottom, but, under the action of the depression arm, weaker springs allow it to sink through the cutting head plate, whose depression springs are stronger. The cradle therefore sinks first, the cutting head second, once the tyre tread has made contact with its rollers. A cable and sleeve is shown in the bottom left corner, showing how the cable would be able to draw down the crash arm as force (t) from the depression arm works on the cradle assembly. (The attachment at the crash arm end is shown in Figure 5) B. The cradle assembly is both wider and longer than the cutting head, enabling the cradle assembly to fit over the cutting head whilst still supporting a tyre.

Figure 4a A. Side view of the way the depression arm drive wheels press down on the tyre and the cutting head assembly via pressure on the rollers. Note position of the blades at (B) in between the rollers and appended to the scissor arms. The springs illustrate the resistance necessary against a fixed plate (not shown) to return the cutting head to the start position. B. The scissor assembly turns downward force into sideways movement of the blades. Arrows show the direction of force carrying the whole assembly downwards, and as the legs spread on the wedge, so the bladed arms extend outwards. Note that the fulcrum will rise slightly, relative to the blade plane, along the dotted line (g). The scissor fulcrum is therefore fixed on a sliding sprung plate to the cutting head assembly. The blades, however, are fixed directly to the cutting head assembly along the horizontal y’ plane. C. The compensating wheel assembly viewed from above. Here it is clear that the wheels brace against the tyre walls under tension before the blade bites. Once the blade is through, the lower of the two wheels in the illustration will push the severed wall outwards, creating less friction. Other designs of compensating wheel assembly and springs are possible.

Figure 4b A. This is an alternative to the scissor assembly in Figure 4a. To operate the blades, a force is applied laterally to the hinged diamond shaped assembly at (K) making the two comers at L2 extend outwards. The blades and compensating wheel assemblies are attached to these comers. The design is further explained in Figure 7. B. This is an alternative to the compensating spring wheel assembly. Here the spring assembly frame is fixed rigidly to the blade assembly, but each wheel, upstream and downstream of the blade, is individually sprung. It is also possible to use a single wheel and spring (not shown)

Figure 5 A. The crash arm is operated by a cable whose loading mechanism was show in Figure 3. This shows the assembly in the raised start position with no tension on the spring. B. As load is applied to the cable end attached to the sinking cutting head by force (t), the crash arm is pulled downwards, tensioning the return spring. C. Upon release of tension created by force (t), both the cutting head and the crash arm will rise to fling the severed tyre wall clear, creating force (n).

Figure 6 A. An alternative to the scissor mechanism is a pipe attached to the cutting head and a fixed lug. The pipe will both revolve and move up and down. As force t drives the pipe down, the lug engaged in the diagonal slit trench forces it to twist. At the top two arms throw out and force the blades, held in tracks, to slide towards the tyre wall. B. As an alternative to the lug and trench, fixed guide wheels can follow a raised edge, so that it is the edge that moves the pipe.

Figure 7 A. This is a continuation of 4b, showing the how the Diamond assembly is made to move at (LI) when downward pressure (t) is applied to the cutting assembly, of which it is a part. Each of the two corners (LI) is connected to a bogie (Z) which runs down the slope of a fixed sloping ramp, as well as laterally inwards, along tracks affixed to the underside of the cutting assembly framework. This causes the diamond to contract at (LI) and the corners at (L2) to move apart, thus operating the blade mechanism to which they are attached. B. A detail of the bogie (Z) shows how the fixed slope and tracks of the cutting head assembly might be off-set, so that they do not collide as the cutting head assembly sinks.

Figure 8.

This shows distances on the machine which need to be adjustable, as different sized tyres behave differently. p: controls how far a tyre is allowed to fall laterally, namely the distance on the y axis between the centre of the cradle and the innermost point of the crash arm which it will strike. This will help the tyre to be centred correctly on the cradle. (Dictated by width of tread) q: Controls the height between the base of the ramp and the crest of the cradle. (Dictated by radius) r: Controls the distance on the y axis between a given point on the ramp and the crest of the crash cradle. (Dictated by radius and depth of rim) The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein.

It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Similarly, it is to be noticed that the term “connected”, used in the description, should not be interpreted as being restricted to direct connections only. Thus, the scope of the expression “a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. It means that there exists a path between an output of A and an input of B which may be a path including other devices or means. “Connected” may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. For instance, wireless connectivity is contemplated.

Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of die phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects.

Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. Flowever, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value.

The use of the term “at least one” may mean only one in certain circumstances.

The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims.

It is important to understand the directions being referred to in the description. Figure Two shows the two planes that will be featured: The Direction of Rotating Tyre (DTR) is parallel to the ramp and will correspond to the plane on which lies the circumference of the tyre at any point in the operation. This will be the x axis, or x vector. The plane Perpendicular to the DTR is the Direction of Fall when the tyre topples (DOF), the y axis, or y vector.

Step One: Loading

The uncut tyres are stored in a cartridge (Figure One). This may be a long ramp, the end nearest the cutting machine being the lowest point, with enough gradient for the tyres to roll down it under their own weight. The waiting tyres are held back by a tilting mechanism (PI) under the floor of the ramp whose two ends can protrude through two holes about 50cm apart lengthways along the ramp, allowing about 15cm of obstruction to stand proud of the ramp floor. Only one end protrudes at a time. The obstruction, which may simply be a length of wood, faces the tyre tread, and forms a chock. When the tyres are waiting, the chock at the lower end of the mechanism may be raised to hold back the lowest tyre, whilst the upper chock is hidden. To release this tyre, the tilting mechanism may be operated, so that the chock at the lower end that was holding the tyre sinks down, releasing the tyre; at the same time the other chock rises to hold back the next tyre. After a short interval the tilt may be reversed, allowing the second tyre to roll down to the waiting position where it is checked by the lower chock that is now raised again, thus completing the cycle. (Fig 1) The released tyre descends the ramp along the x vector, and on reaching the point directly in front of the loadbearing column, known as the Trap, bumps into an upright obstacle which checks its roll. Because the base of the Trap may either be very narrow (as in Tl), or slope away along die y axis towards the cutting arm (as in T2), the tyre is unstable and the top of it topples sideways (y vector) onto the cutting arm. This can be assisted by profiling the rear vertical wall of the trap to have a projection (T3) at the point where it rubs the top of a tyre, so that the top of the tyre is jolted along the y axis towards the cutting arm. ( Fig 3) The top of the tyre falls onto one or more inverted V-shaped cradles (C) with a hinged (H3) arm at the back, raised to check the tyre’s further y vector fall. This arm mechanism will be called the ‘Crash Arm’ (CRA). (Fig 1) At this point the bottom of the tyre needs to come free from the Trap too. In one version the Trap consists of a hinged section with a narrow top edge running along the x axis (Tl). The spring-tensioned hinge (HI) is underneath, allowing the top edge to tip back along the y vector, away from the cutting area. It also has rollers on the top edge that roll in the y vector. As the tyre topples, it starts to apply y vector shearing force to the top edge of Tl as the top of the tyre moves in the opposite direction, allowing the rollers (Rl) to slide the base of the tyre off. This causes the base of the tyre to fall completely free, so that it is now suspended by its rims from the cradle (Fig 3) (Fig 2) in the cutting position. The crash arm must be adjustable, so that its tip may be at a variable distance from the centre of the cradle on the y axis.The trap will also be adjustable in its height relative to the cradle and in its distance laterally from the cradle to allow different settings to suit the various tyre sizes, since their falling position relative to the cradles is critical. An alternative to T1 is shown in T2, where the hinge along the x axis at (H2) allows the wide but sloping support to collapse once the top of the tyre has engaged with the cradle, allowing the tyre to fall free.

Step Two: Preparing to cut (Figure 3) The sloping cradle surfaces (C ) on which the tyre now sits (seen here in cross-section) also consist of a sliding surface such as rollers (R2). The inverted V shape and the action of the crash arm allow the tyre rims to settle reasonably centrally, helped by the weight of the whole tyre being suspended from this point. However, the centralising process is assured when the tyre is subjected to rotation from a powered wheel (W in Fig. 4) attached to the depression arm just above it, the rollers allowing the optimum centrality to be reached.

Below, and positioned between the cradles, is the cutting head (CH) . When the tyre is depressed by downward pressure (t) from above, the cradle will offer some sprung resistance to the rims, both in the springs SI and in the Crash Arm spring S3 in Fig.5. As it sinks, the rims still on the cradles, the tyre will soon engage on the underside of the tread, ie. the inside surface of the tyre, with the cutting head rollers. (The cradles are positioned to the outside of the rollers, so do not obstruct the cutting head, and although they continue to engage with the rim of the tyre harmlessly, their job is done for the time being.) Thus far the process is essentially the same for all designs of cutting process.

Step Three: Low Tech Cutting (Figure 4A) There now follows a description of a low-tech cutting option. When the rotating tyre sinks onto the rollers (R4) of the cutting head (CH) assembly, such that the cutting head assembly is now enclosed inside the tyre, the drive wheels or drive rollers (W) continue to press down on the internal rollers (R4), which are part of the sprung cutting head (S2). The source of the motion and downward force is the Depression Arm (D in Fig 2) with rotating drive-wheels or rollers (W) at its end. The drive wheels or drive rollers will cause the tyre to rotate at a moderate rate as well as sink, by virtue of the arm’s action downwards upon the sprung cutting head. The depression arm’s movement up and down may be operated by a rack and pinion system inside the stem of the ‘cactus’, ie. the loadbearing column supporting the arms, so that its drive wheels or rollers remain accurately centred, whatever the width of tyre.

The challenge here is firstly to get the blades (B) of the cutting head to cut the walls as near to the tread as possible without their coming into contact with the steel web that is part of the tread itself, since that would blunt them; secondly, to get the blades to enter their respective walls as near as possible to simultaneously. Both these processes must occur reliably whatever the width of the tyre, the depth of its tread, or its radius. The two blades must approach the parallel cutting spots in a controlled manner, penetrate the tyre wall simultaneously, and cease further penetration once an optimum position or depth has been reached. There may be an adjustment facility to enable the exact height of the blades or the exact height of the cutting head rollers to be altered.

To cease penetration at an optimum depth the blade assembly will have a mechanism that responds when forced against the tyre wall. Alternatively this result can be achieved by using the jolt created in the compensating wheel assembly as the blade breaks through to create a changed position in a switch. Either solution can operate a switch controlling the depression arm’s movement, causing it to cease descending, thereby halting the extension outwards of the blades.

The movement of the blades can be actioned by a scissor-shaped mechanism whose ‘arms’ (SA) open progressively as the tyre is depressed, the ‘legs’ (SL) of the scissors being spread as they pass down a fixed widening wedge shape (Z) under the force (t) of the drive wheels (W). The tops of the scissor arms are attached to the two blades (B), so that as the scissor legs spread, the blades at the top of the scissors move outwards. Thus, when the rotating tyre is caused to sink under the pressure from the depression arm, the blades start to cut through its walls; the wider the tyre, the lower it will have to sink before the cutting takes place. The scissors are attached at their fulcrum point (FI) as a sliding fit to the cutting head assembly, which is in movement downwards, whilst the wedge is fixed to the stationary frame of the machine. The attachment of the scissors to the cutting assembly at their fulcrum is a sprung sliding fit up and down. (Since the ends of the arms are held in a fixed horizontal plane, this movement at the fulcrum is necessary, due to the change in length ‘g’ in the shifting triangle created in the scissors’ movement, where a right-angle is maintained between the blade plane and the verticality of the scissors).

The two blades are mounted on the top of the scissor arms that spread as the tyre is depressed. At or near the point of attachment of the blades to the scissors may be a fulcrum (F2), on each scissor arm, where is held a hinged (H4) compensating assembly (WA)of wheels on a spring or springs (S3): Two separate, vertically-axelled wheels (W2), one each side of a blade, are mounted on the two ends of a pivot such that the two wheels engage the inside of the tyre wall before the blade does: one is upstream’ of the blade, the other ‘downstream’, where the stream refers to the direction the tyre is turning in. This means that as the two upper ends of the scissors diverge, it is the four wheels that first press against the inside tyre walls, centralising and steadying the rotating tyre relative to the cutting assembly. As the depression of the tyre continues, the blades approach and then begin to cut the tyre walls; when finally they penetrate, the assemblies swivel slightly and the wheels ‘downstream’ of the cut force the severed tyre wall outwards, making for less friction at the point of cut. The upstream wheels now rest against the still intact tyre walls, whilst the downstream wheels hold the severed section of wall clear of the point of cut, thanks to the compensating hinge and action of the springs (H4). A simpler design might use two or even one rigid sprung wheel per blade. It is possible to add a vibrating device to the assembly so that the vibration that passes through the blades aids the cutting process further.

Step Three: Further Cutting option (Figure 4B). Here the idea is to use a related principle to the scissors, the horizontal diamond shape, whereby each comer of a parallelogram is hinged (H4): an x vector force (K) on one or both comers (LI) causes the two adjacent corners (L2) to expand along the y vector, meaning that it converts x vector into y vector force. The proximity of the rollers (R4) to the blades (B) means that the horizontal diamond itself is likely to be positioned well below the rollers and tyre, where it has more room to operate. The blade assemblies and compensating wheel assemblies are a vertical extension of the two opposing comers (L2). (Figure 7) The diamond is spread at (L2) by using two converging sloping surfaces to act as guides for two concave wheels at LI, so that as the diamond assembly is forced downwards, the bogie wheels at LI move inwards and down along the slopes, much as the wedge operates the scissors. To force the diamond down, the cutting assembly pushes onto these same bogies via wheels on the top of the bogie that run along tracks affixed to the underside of the cutting head.

Thus downward force become x vector force in the bogies which, thanks to the diamond’s action, becomes y vector force at the blades.

Step Four: Cutting and removing the Tread

Once the two severed tyre walls have fallen away, the tread can be cut. This is done by a guillotine with a circular blade that is mounted as a sliding fit on one side of the depression arm. The guillotine assembly therefore emerges towards the end of the whole cycle to cut the tread. The guillotine has several sprocket wheels in opposition to each other which ‘snatch’ the tread and force it, by dint of their direction of rotation, inwards and onto the guillotine blade which cuts the tread, working against two further tightly fitting wheels to either side of the blade whose centres are on the opposite side of the tread. There is also a roller assembly on the other side of the arm from the guillotine that grips the severed tread at one end, and by the action of rollers sends the tread clear of the machine after the cut is made.

Step Five: Removing the inner Tyre Wall

The final problem to be solved is how to remove the severed tyre walls from the machine. The left hand, or outer tyre wall falls away by gravity down one side of the Inverted V of the cradles and can be made to roll away without difficulty. However the wall on die loadbearing column side of die cutting head is trapped in a straddling position over the cutting arm (CA) (see Fig 2) because the tyre wall is looped over its upper arm, between ‘elbow’ and ‘shoulder’. (Figure 5) The solution is as follows: The Crash Arm assembly (CRA in fig 3), hinged to the cradle assembly (H3), was at the start of the cycle in the upright position (1) when preventing the tyre from tipping too far during the loading phase. As the cradle assembly is made to sink, this same downward force (t) is used, via a cable (El in fig 5 and E2 in fig.3). The cable end is connected at E2 (fig.3) to the cradle assembly and the sleeve at E2 is connected to the cutting head. At El (fig.5) the cable is connected to the Crash Arm, and the sleeve at El to the cradle assembly. The downward force (t) therefore depresses the Crash Arm and tensions the spring (S3), which will create a potential in the spring for force (n). At the end of the cutting head descent the Crash Arm is at an angle well below horizontal (2). At its end the arm is bent upwards to form a hook shape so that the severed tyre wall is caught by the hook at the end of the Crash Arm when it falls off the tread. This end of the crash arm may contain some adjustability to allow its variable position relative to a tyre falling against it.

To release it we use the centralising cradle device as follows: two spring loaded forces, (t) and (n), are used to propel the tyre wall upwards and sideways, back towards position (1), so that the top of the tyre wall can clear the cradle mechanism forwards along the y vector, while the bottom of the tyre wall remains somewhere beneath the ‘elbow’ of the cutting arm. The first force, (t) can come from the springs (SI in fig 3), mounted at various points between the cradle assembly and cutting Head, that were loaded by the downward depression of the tyre. These springs will later project the cradle assembly upwards. At the same time the Crash Arm, which was spring loaded by force (t), will flip smartly back to vertical with the force (n) of spring S3 (Fig.5), which means it will eject the tyre wall along the y axis. The combination of these two actions will eject the tyre wall clear of the Cutting Arm. A simple release mechanism is required to set off this ejection, and this can be achieved mechanically or with a solenoid. A length of material of approximately 700mm may be secured to the lower surface of a ramp at a pivot, and may have a chock at each end that can protrude through a hole in the ramp, such that only one chock can be protruding through its hole at any one time. A rolling tyre on a ramp may be checked by an obstructing surface facing the tread at a point where the tyre is opposite the cutting head, which point will be referred to as the Trap.

The ramp side wall furthest from the machine at the trap may contain a projection at the point where it is adjacent to the upper area of the tyre wall, so that the tyre is destabilised and forced to topple away from this sidewall.

The ramp’s upper surface may slope downwards towards the cutting head, or may be sufficiently narrow to make a standing tyre unstable.

At the trap the base of the ramp may be hinged, collapsing either downwards or backwards (ie. away from the cutting head).

The base of the ramp at the trap may have rollers affixed to its upper surface.

The height of the trap surface may be controlled and adjustable.

The lateral position of the ramp (along axis y) relative to the cutting machine may be controlled and adjustable. A cradle assembly may consist of at least two convex cradles, their central point being highest and the downward sloping sides perpendicular to the tipping tyre, and may have a spring mechanism that allows vertical movement relative to a separate base when pressure is applied from above.

The sides of the cradle in (7) may contain one or more low friction surfaces or roller devices on their upper edge.

The cradle assembly may have one or more arms, known as crash arms, hinged at the base of the cradle assembly on the side furthest from the tipping tyre, such that when these arms are in a raised position, either vertical or not more than 60 degrees from vertical, they prevent the tipping tyre from falling beyond the cradle assembly.

The crash arms may have an upwardly curved profile at their free end , such that when they are in a lowered position, more than 5 degrees below horizontal, they will catch a falling severed tyre wall and prevent it from falling further than the hooked end of the arm. The end of the crash arm may be adjustable to allow a variable distance relative to the crest of the cradles.

The assembly may have a cable attached to the crash arm of which the cable sleeve is attached to the cradle, along with a spring attached at these or equivalent points, so tliat the crash ami can be lowered by the action of the cable and returned to the upright position by the action of the spring or springs.

The assembly may have a powered mechanism such as a hydraulic or a pneumatic cylinder assembly attached at one end to the crash arm and at its other end to the cradle, in order swiftly to return the crash arm to the raised position.

An arm, referred to as the Depression Arm, may have one or more powered drive wheels or drive rollers at its end that revolves in the same plane as the tyre (ie. the x axis)

The Depression Arm may have rails running the length of either side or both sides that permit lateral movement by an attached object

The Depression Arm may have a guillotine assembly on one side that can move horizontally along the Arm

The Depression Arm may have a roller assembly on one side that can move horizontally along the Arm

The Depression arm may use a device, such as a rack, pinion and motor, to move it both upwards and downwards. This may involve a rigid track or threaded bar. A cutting assembly that is free to move upwards or downwards relative to the machine superstructure may consist of one or more rollers positioned such that they can rotate along the x axis when in contact with the inside of the tyre tread.

The cutting assembly may have one or more cutting blades mounted horizontally on either side of the assembly along the y axis, such that the blades will cut into rotating tyre walls at or near to the joint between tread and walls, when forced against them.

The height at which the blades make contact with the tyre wall and the height of the cutting head rollers may be controlled and adjustable.

The cutting assembly may have one or more wheels to one side or on either side of the blade or blades, their axles vertical or near to vertical, such that the wheels rotate when pressed against the inside of the tyre wall.

The wheels may be mounted each end of a sprung mechanism with a fulcrum at a point between the two ends, such that the two wheels and the spring or springs form a compensating wheel assembly, when the assembly is affixed at its fulcrum at a point on or near the blade assembly. A wheel or wheels in 23 may be mounted on bars to a part of the blade assembly such that the bars form a sprung sliding fit.

There may be a device attached to the compensating wheel assembly in (24) or (25), or to a wheel in (23) which, when the blade breaks through the tyre wall, sends a signal to a switch on the lowering mechanism of the depression arm.

There may be a device, performing the function as described in (26), attached to the blade assembly that responds to the proximity of the tyre wall.

There may be a vibrating mechanism connected to the cutting assembly such that the blades vibrate at a high frequency.

There may be a scissor-shaped device, mounted vertically and perpendicular to the rotation direction of the tyre, consisting of two lengths attached towards their middle at a fulcrum, such that the motion of the ends at the lower end causes the top end of the lengths to act in unison with the lower end when the lower ends are forced to move apart. A scissor-shaped device as in (29) is attached vertically at its fulcrum, but with the ability to slide upwards or downwards, to a framework that is part of the cutting assembly, and at the top of the two scissor arms to the two blade assemblies, such that when the lower ends of the scissor-shaped device are forced apart the blades are also forced apart and the fulcrum forced to rise. A wedge shaped device may be attached to the superstructure of the whole machine, and therefore not joined to the cutting assembly, such that two of its surfaces are joined to form an upwards facing arrow that is perpendicular to the direction of tyre rotation, whereby the slopes of the wedge offer a surface on which the legs of the scissor shaped device can rest, such that when the scissor shape and cutting assembly is depressed, the immobile wedge-shaped surfaces down which the legs travel cause the ends of the scissor shaped device to move apart from each other .

As an alternative to the scissor-shaped device, a tube or bar may be affixed vertically to the framework of the cutting assembly such that it can swivel but not move up or down relative to that assembly, that has affixed horizontally at its top a bar or elongated shaped piece that lies along the direction of tyre rotation and between two opposing blades, such that when the bar is rotated the horizontal bar or elongated shaped piece swivels and causes the two blades to move apart. A tube, as in (32) that has a trench or elongated hole cut into it in a diagonal direction moving from a top position to a lower position no less than 5 degrees and no more than 90 from the top position in terms of lateral movement. A lug attached to the immobile superstructure of the machine that engages in the trench in (33)

As an alternative to (33) and (34), a ridge replaces the trench in (33), and a guide wheel assembly the lug in (34), so that the wheel assembly engages with the ridge to perform the same function.

As a further alternative to the scissor assembly in (29), there may be a hinged horizontal parallelogram structure, where a lateral force may be applied at one corner (LI) along the x axis, making the two adjacent comers (L2) move along a fixed path outwards along the y axis, and where a blade assembly and compensating wheel assembly are attached to each of these same adjacent corners (L2 in Figure 4B). A horizontal parallelogram structure as in (36) may have a powered force acting on it at LI. A horizontal parallelogram structure as in (36) may connect at each of its two comers (LI) with a wheel or a wheel assembly such as a bogie, whereby the wheels or bogies engage with two rigid slopes that converge symmetrically towards each other at a lower point, aligned along the same x axis as the comers (LI).

The structure in (36) may connect at each comer at (L2) with the blade assemblies.

An assembly of convex cradles that have rollers attached to their top surface whose support is sprung such that the assembly can be lowered relative to the machine.

An assembly of arms with upward turned ends, hinged to one side of the cradle assembly, that can be lowered to a position below the horizontal and made to return to the raised position in one brisk movement.

Claims (21)

1. A tyre cutting machine for separating a tread of a pneumatic tyre from sidewalls of the pneumatic tyre, the machine comprising: a tyre support, configured to receive a tyre thereon, the tyre support configured to engage an interior surface of the tyre's tread, such that the tyre hangs from the tyre support; a first cutting blade, arranged to be engagable with an interior of a first annular shoulder region of the tyre between the tread and a first sidewall of the tyre; a second cutting blade, arranged to be engagable with an interior of a second annular shoulder region of the tyre between the tread and a second sidewall of the tyre; a blade movement mechanism configured to move the first and second cutting blades into engagement with the respective shoulder regions in response to the tyre support receiving the tyre thereon; and a tyre drive mechanism for driving the tyre about its axis when supported on the tyre support.

2. The tyre cutting machine of claim 1, wherein the tyre support comprises a roller, a track, a low-friction surface and/or bearings.

3. The tyre cutting machine of claim 1 or claim 2, wherein the tyre drive mechanism and/or the tyre support comprises a roller, a track, and/or similar transmission.

4. The tyre cutting machine of any preceding claim, wherein the tyre drive mechanism is arranged to engage the interior surface of the tyre's tread, an exterior surface of the tyre's tread and/or an interior and/or exterior surface of the first and/or second sidewall of the tyre.

5. The tyre cutting machine of any preceding claim, wherein the tyre drive mechanism is configured to press down on an exterior surface of tyre when supported on the tyre support, and/or the blade movement mechanism is configured to move the first and second cutting blades substantially horizontally outward in response to pressure exerted by the tyre drive mechanism.

6. The tyre cutting machine of any preceding claim, wherein the blade movement mechanism is configured to move the first and second cutting blades substantially horizontally outward in response to the tyre support receiving the tyre thereon.

7. The tyre cutting machine of any preceding claim, wherein the blade movement mechanism is configured to move the first and second cutting blades substantially simultaneously.

8. The tyre cutting machine of any preceding claim, wherein the blade movement mechanism is configured to move the first and second cutting blades a distance positively correlated with a weight of the tyre, such that the blade movement mechanism moves the first and second cutting blades a greater distance for a heavier tyre than a lesser distance for a lighter tyre.

9. The tyre cutting machine of any preceding claim, wherein the blade movement mechanism is configured to stop outward movement of, and/or at least partially retract, the first and second cutting blades in response to the first and second sidewalls being separated from the tyre tread.

10. The tyre cutting machine of any preceding claim, wherein the blade movement mechanism is configured to fully retract the first and second cutting blades in response to the tyre being removed from the tyre support and/or pressure exerted by the tyre drive mechanism being removed from the tyre.

11. The tyre cutting machine of any preceding claim, further comprising first and second sidewall biasing members, arranged to bias the first and second sidewalls outward, respectively.

12. The tyre cutting machine of claim 11, wherein the blade movement mechanism is configured to move the first and second sidewall biasing members such that they bias the first and second sidewalls outward, respectively.

13. The tyre cutting machine of any preceding claim, further comprising a vibrator, configured to vibrate the tyre, the tyre support, and/or the first and second cutting blades.

14. The tyre cutting machine of any preceding claim, further comprising a tyre loading mechanism, configured to load tyres onto the tyre support.

15. The tyre cutting machine of any preceding claim, further comprising an arm located in a loading position adjacent to the tyre support on a first side of the tyre support, the arm configured such that tyres loaded onto the tyre support from a second side opposite the first side are prevented from falling off the first side of the tyre support.

16. The tyre cutting machine of claim 15, wherein the arm is configured to move out of its loading position adjacent to the tyre support once a tyre has been loaded onto the tyre support, and into a waiting position.

17. The tyre cutting machine of claim 16, wherein the waiting position is located such that a sidewall of a tyre located on the first side of the tyre support may be caught by the arm in response to said caught sidewall being separated from the tyre tread.

18. The tyre cutting machine of claim 17, wherein the arm is configured to propel said caught sidewall over the tyre support onto the second side of the tyre support.

19. The tyre cutting machine of any preceding claim, further comprising a tread cutter, arranged to cut across the tread of the tyre in a direction parallel to the axis of the tyre.

20. A method of separating a tread of a pneumatic tyre from sidewalls of the pneumatic tyre, the method comprising the steps of: providing a tyre cutting machine according to any preceding claim; providing a tyre to be cut; engaging an interior surface of the tyre's tread on the tyre support, such that the tyre hangs from the tyre support; moving the first and second cutting blades into engagement with the respective interiors of the shoulder regions in response to the tyre hanging from the tyre support; and driving the tyre about its axis.

21. A tyre cutting machine substantially as hereinbefore described with reference to the accompanying drawings.