GB2481403A

GB2481403A - Lead control apparatus comprising a one-way brake

Info

Publication number: GB2481403A
Application number: GB201010444A
Authority: GB
Inventors: Jesper Ba Ck
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-06-22
Filing date: 2010-06-22
Publication date: 2011-12-28
Anticipated expiration: 2030-06-22
Also published as: GB2481403B; GB201010444D0

Abstract

Apparatus for controlling a lead comprises an extendable lead 2 and a storage reel 10, 12 for the lead which is extended under tension by forward rotation of the reel. Retraction means, such as a flat coil spring 22, are arranged to urge the storage reel to rotate backward against the tension in the lead. A means for selecting a maximum extension length for the lead comprises a one-way brake 38 preventing the storage reel from rotating forward and releasing the lead further once it is extended to the selected length. This allows any slack in the lead to be taken up whilst preventing the lead extending beyond the selected length. The selection means preferably comprises a rotary selection switch or an adjustable lever 36 that is manually activated to select a desired maximum extension length for the lead. The one-way brake may comprise a gear mechanism coupled to the storage reel comprising an adjustable stop which limits motion of the gear mechanism according to the extension length selected. The gear mechanism may comprise an adjustable cam or a threaded gear follower. The lead is stored in a generally annular chamber circumscribing a hand grip of the apparatus.

Description

Lead control apparatus The present invention relates to an apparatus for controlling a lead, in particular an extendable and retractable lead of the type commonly used to restrain domestic pets such as dogs.

In its most basic form, a lead provides an animal with some freedom of movement while keeping it within a set distance from its handler. Animals such as dogs are often kept on a lead when being exercised so that they can not run too far away or interfere with other animals and people without being under control. A problem with traditional leads is that unused lead may trail on the floor when the animal is close to its keeper, which can become tangled with feet and cause a hazard. The total length of such leads is therefore normally limited to only one or two metres.

Retractable leads have been developed where the lead can reel off a spool as required. A spring is usually arranged to drive the spool in reverse and retract the lead automatically when it is not pulled out in tension. Such retractable leads can enable an animal to roam further from its keeper, typically providing a maximum extension length of up to five metres for the lead, while ensuring that any slack in the lead is reeled back in when the animal moves closer. This provides the animal with a much larger degree of freedom.

On the other hand, leads that are freely extendable and retractable may not be appropriate in all animal handling situations. The animal may quickly run away and pull the lead out to its maximum extent before the handler has time to react. It can be difficult to control the length of lead that is unreeled. If the animal is released from an extended lead, either accidentally or voluntarily, then the suddenly slack lead can be pulled back onto the reel at high speed and potentially fly back to strike the user.

As retractable leads can be extended on demand, they are not always appropriate in situations where it can be desirable to keep an animal close to its handler, for example when walking along pavements in an urban setting. In order for the animal handler to control the maximum extension length of the lead, the spool is often provided with a manually activated brake. Once the brake is applied the lead cannot be released any further. The animal may therefore be kept on a short tether with a controlled length of lead.

However a problem with using a spool brake to limit the length of the lead is that the retraction function of the lead is lost. If the lead is locked at an extension length of two metres but the animal then runs up to its handler, the excess lead will not be reeled back in but will lay on the ground. The lead may become tangled and wrap around the feet. This can be a problem in a busy urban environment. The handler may not be able to react straightaway by releasing the brake and re-adjusting the free length of lead, especially if he or she is busy at that moment attending to the animal's toilet needs.

Retractable leads may also be used to control children when attached to a child harness, giving toddlers, for example, freedom to explore safely within range of a parent or carer.

The present invention seeks to provide improvements in controlling a lead.

According to a first aspect of the present invention there is provided apparatus for controlling a lead comprising an extendable lead and a storage reel for the lead, the lead being extended under tension by forward rotation of the reel, and retraction means arranged to urge the storage reel to rotate backward against the tension in the lead, the apparatus further comprising means for selecting a maximum extension length for the lead, said selection means comprising a one-way brake preventing the storage reel from rotating forward and releasing the lead further once it is extended to the selected length.

According to the invention a selection means allows a user of the apparatus to select a maximum extension length for the lead that it less than the lead's maximum possible length. However, rather than simply stalling the storage reel completely when a desired maximum length is reached, the one-way brake prevents only forward rotation and therefore the retraction means can still act to reel in the lead if the tension is released, for example by an animal on the lead moving closer again.

It will be understood that the animal on the lead can move to different distances within the range of the selected maximum lead length, and the lead can extend and retract with the animal. This is a distinct improvement over apparatus where the reel is prevented from rotating either forward or backward when a normal brake is applied to limit the length of the lead.

The selection means preferably enables a user to manually preset a desired maximum length for the lead. The selection means may provide one, two, three, four, five or more different presettable lengths for the lead. So, for example, for a lead of total length 5 metres the selection means may enable a user to preset a maximum extension length of 1, 2, 3 or 4 metres. The apparatus can therefore provide a large degree of flexibility in controlling the length of the lead.

A user can set a desired maximum length for the lead depending on the current environment, e.g. a short length of 1 or 2 metres in a busy area or a longer length of 3 or 4 metres in an environment where the animal can safely roam further from its handler. The different selectable lengths for the lead may beneficially be used in animal training. A further advantage is that the apparatus can easily be adapted to different sizes and even types of animal, with the lead length being selected according to the animal on the lead.

In order to enable a user to select a desired maximum extension length, the selection means preferably comprises a lead length selection switch. The switch may take any suitable form, including a linear switch or toggle. However in a preferred sets of embodiments the selection means comprises a rotary selection switch that is manually activated to select a desired maximum extension length for the lead. A rotary switch may be easier and more convenient for a user to operate, for example using only a thumb to turn the switch while gripping the apparatus. The rotary selection switch may comprise a rotatable actuator such as a knob or lever.

The selection switch may allow a user to select from a continuous range of maximum extension lengths for the lead. However, as mentioned above, it is preferable for the maximum extension lengths to be preset in the apparatus. Thus it is preferred that the selection switch is manually movable between a number of positions, each corresponding to a different maximum extension length for the lead.

The selection switch may be movable between one, two, three, four or five different positions corresponding to one, two, three, four or five different preset maximum extension lengths for the lead.

The selection means is a key feature of the invention but it may take many different forms in the detail of its mechanism. In preferred sets of embodiments the one-way brake of the selection means comprises a gear mechanism coupled to the storage reel. Advantageously, motion of the gear mechanism corresponding to forward rotation of the storage reel can be controlled depending on the extended length of the lead. Thus the gear mechanism can operate to prevent the storage reel from releasing the lead further once it is extended to the selected length.

There may be envisaged many different ways of controlling motion of the gear mechanism. Generally these is required a part of the mechanism that can be adjusted depending on selection of a maximum extension length for the lead and another part of the mechanism that is acted on according to the adjustment. In one set of embodiments, the gear mechanism comprises an adjustable stop. Preferably the position of the adjustable stop can be adjusted to limit motion of the gear mechanism according to the maximum extension length selected. In another set of embodiments, the gear mechanism comprises an adjustable cam. Preferably the position of the adjustable cam relative to a stop can be adjusted to limit motion of the gear mechanism according to the maximum extension length selected. Of course any combination of mechanical components such as stops and cams, or other suitable components, may be used to control the gear mechanism depending on the extended length of the lead and the maximum extension length selected.

In a particularly preferred set of embodiments, the gear mechanism comprises a gear wheel rotationally coupled to the storage reel. This provides a straightforward way of controlling the rotation of the storage reel and thus the extension and retraction of the lead. Motion of the gear wheel may then be controlled by the selection means depending on the extended length of the lead. Various ways of controlling motion of the gear wheel may be envisaged.

In one preferred set of embodiments, the gear mechanism comprises a gear wheel rotationally coupled to the storage reel and a threaded gear follower that moves linearly along the axis of the gear wheel according to rotation of the gear wheel until it meets an adjustable stop. Preferably the linear position of the adjustable stop along the axis of the gear wheel can be adjusted to limit rotation of the gear wheel according to the maximum extension length selected. In another preferred set of embodiments, the gear mechanism comprises a gear wheel rotationally coupled to the storage reel and an adjustable cam that rotates with the gear wheel until it meets a stop. Preferably the rotary position of the adjustable cam relative to the gear wheel can be adjusted to limit rotation of the gear wheel according to the maximum extension length selected. Both of these gear mechanisms benefit from comprising a limited number of mechanical components such that they can be made fairly compact and may not require a lot of space in the apparatus. They may also be manufactured and assembled at reasonable cost. Furthermore, such gear mechanisms have been found to be robust and reliable.

Although the selection means may be used as the only means of controlling the lead, as it can provide flexibility in selection from a range of maximum lead lengths, it may be desirable that the lead can also be locked at a desired length. Thus it is preferable that the apparatus further comprises brake means actuable in a mode of operation to prevent extension or retraction of the lead. Preferably this brake means is manually actuable. When the brake is applied the lead is locked at a fixed length. This turns the extendable lead into a traditional lead and allows the tension in the lead to be relaxed, which may be desirable in certain circumstances.

Furthermore the brake means advantageously provides a user with an additional level of control, as preferably the brake can be actuated at any time to select a desired extension length other than the maximum extension length(s) allowed by the selection means.

The brake means may take any suitable form and various mechanisms can be envisaged. Although the brake means could be arranged to act on the lead itself, for example securing the lead to prevent it from extending or retracting, it is preferred that the brake means is arranged to act on the storage reel to prevent the reel from rotating forward or backward. The reel is therefore locked not only against unreeling the lead out further but also preferably against reeling the lead back in under the force of the retraction means, unlike when the one-way brake of the selection means is applied.

In one preferred set of embodiments the brake means comprises a pawl arranged to engage with teeth provided on the storage reel. This is a simple and effective braking mechanism that can be implemented without unduly interfering with the lead wrapped on the reel. For example, the teeth can be provided around the circumference of the reel at its periphery. In order to help ensure that the brake only acts when manually applied, it is preferable that the brake means comprises a spring arranged to bias the pawl out of engagement with the storage reel.

Although in a preferred mode of operation the brake acts to prevent both forward and backward rotation of the storage reel, there may additionally be provided a mode of operation wherein the lead can not be extended any further but it can be reeled back in under the control of the brake. This could be useful, for example, where the lead has been extended to a long length and it is desired to reel in the lead in a controlled manner rather than under the full force of the retraction means.

This could help prevent the extended lead from flying back into the apparatus at high speed. Thus in a preferred set of embodiments the pawl of the brake means can be applied in another mode of operation to provide a ratchet mechanism preventing forward rotation of the storage reel. In such a ratchet mechanism the teeth on the storage reel may be angled such that the pawl can move over the teeth when the reel moves backward under the force of the retraction means. However forward rotation is prevented whenever the pawl is engaged with the teeth.

It is also preferred that the brake means comprises a lock, so that a user can remove his hand from the brake and the lead at least will not extend any further while it is locked, Preferably the length of the lead is fixed while the lock is applied.

Thus it is preferred that the lock holds the brake means in a mode of operation wherein the storage reel is prevented from rotating forward or backward (rather than in a ratchet-type mode of operation as described above).

Thus it will be understood that in a preferred set of embodiments the apparatus comprises both a one-way brake preventing the reel from rotating forward (when a preset maximum length is reached) and means for preventing the reel from rotating either forward or backward (when the brake is applied and possibly locked).

Although combined means may be envisaged that can selectively prevent either forward or forward and backward rotation of the storage reel, it is preferable that the selection means acts on the storage reel independently of the brake means. The Applicant has realised that this can be advantageous for a number of reasons.

Firstly, it means that the selection means and the brake means can each be optimised for their respective function. The selection means needs only to prevent forward rotation of the reel against the tension in the lead, while the brake means needs also to prevent backward rotation of the reel against the force of the retraction means. The selection means will, in many embodiments, comprise a mechanism that allows for selection of more than one different maximum extension length for the lead. By providing the selection means with a mechanism separate from the brake means, it can be ensured that repeat action of the brake will not damage the potentially more sensitive mechanism of the selection means. On the other hand, the brake means can be designed to provide a robust performance without needing to take into consideration the need for variable selection. This preferred set of embodiments therefore provides several advantages.

The Applicant has appreciated that providing a selection means instead of, or in addition to, a conventional brake means may add to the complexity of the apparatus as compared to previous proposals. Additional space may be required, for example in the housing of the apparatus, to accommodate the mechanism of the selection means. However the Applicant has devised a particularly advantageous feature that can help to ensure the apparatus is compact in size. The lead is preferably stored in a generally annular chamber circumscribing a hand grip for the apparatus.

Thus the apparatus is provided with a handle that takes advantage of the necessarily annular geometry arising from the storage reel and its associated retraction means, and uses some of the dead space inside the lead storage space.

This feature is beneficial in a retractable lead apparatus regardless of whether or not the maximum extension length of the lead can be selected.

Such an arrangement is therefore considered both novel and inventive in its own right, and thus when viewed from a further aspect the present invention provides apparatus for controlling a lead comprising an extendable lead and a storage reel for the lead, the lead being extended under tension by forward rotation of the reel, and retraction means arranged to urge the storage reel to rotate backward against the tension in the lead, wherein the lead is stored in a generally annular chamber circumscribing a hand grip for the apparatus.

In one preferred set of embodiments the lead is stored in a chamber defined around the circumference of the storage reel. The storage chamber may therefore have an annular shape that is symmetrical and the apparatus with its hand grip may have a generally circular shape in cross-section. However it will be understood that the lead may not be wrapped around the entire circumference of the storage reel. The storage reel may comprise a track running the lead around a storage space that is not circular but otherwise ring-shaped e.g. oval, oblong, elliptical, pill-shaped, kidney-shaped or otherwise shaped in a generally annular manner.

Preferably the selection means is also provided in a space circumscribed by the lead storage space. This can provide a beneficially ergonomic arrangement wherein the selection means and the handle are provided together in a volume radially inward of the lead storage space, such that a user gripping the handle can easily operate the selection means with the same hand.

All of the preferred features described above, such as the various embodiments of the selection means and brake means, may equally be applied to this further aspect of the invention. In particular, by using a compact arrangement wherein the lead storage chamber circumscribes a hand grip, the apparatus may have more space to accommodate a length selection mechanism without becoming unduly large and bulky. This represents a particularly advantageous combination of features.

There will now be described some further preferred features applicable to both aspects of the invention. Firstly, the storage reel can be any rotary member capable of reeling the lead in and out. In a preferred set of embodiments the storage reel comprises a rotational drive means, such as a drive cog, operatively connected to the retraction means. Although the lead could be wrapped directly onto the drive wheel, this is likely to impose unwanted design constraints on the size of the drive wheel and/or the length of lead that can be accommodate. It is therefore preferred that the storage reel also comprises a carrier for the lead that is rotated by the drive means. The carrier can therefore be sized and shaped as appropriate to store the lead and enable it to be reeled and unreeled easily. The lead carrier may itself comprise a wheel, but it is not limited to a circular geometry.

The lead carrier may comprise any kind of generally annular track that may be driven in rotation. The annular track may, for example, follow an oval, oblong, elliptical, pill-shaped, kidney-shaped, tortuous or otherwise ring-shaped path.

The retraction means may comprise any suitable biasing means arranged to pull the storage reel backward against the tension in the lead. Preferably the retraction means comprises a mechanical spring. A flat coil spring is preferred as it can easily be accommodated inside a rotational drive such as a cog.

The performance of the apparatus may also be enhanced by ensured that the lead is reeled in and out smoothly. It is therefore preferable for the apparatus to comprise guide means to direct the lead from the storage reel as it is extended.

Preferably the guide means directs the lead tangentially from the storage reel. This can help to ensure that the reel runs smoothly. As the extended lead may be twisted depending on movement of the animal, it is also preferable to flatten the lead before it is wound back onto the storage reel. Thus the guide means preferably comprises a tongue arranged to bear against the surface of the lead as it is extended. This helps to flatten the lead as it is guided on and off the reel.

Except where they are mutually exclusive from a technical point of view, all of the individual features set out hereinabove may be provided in any and all combinations within the scope of the invention.

Some preferred embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is an exploded view of a dog lead apparatus according to a first embodiment of the invention; Figure 2 is a cut-away perspective view of the apparatus of Figure 1; Figure 3 is a side sectional view of the apparatus of Figures 1 and 2; Figures 4 and 5 show detail of the selection mechanism in the apparatus according to the first embodiment of the invention; Figure 6 is an isometric view of a dog lead apparatus according to a second embodiment of the invention; Figure 7 is a side view of the apparatus of Figure 6; and Figure 8 is a side sectional view of the apparatus of Figures 6 and 7, It can be seen from the Figures that in both depicted embodiments of the invention the dog lead control apparatus 1 comprises a lead 2 stored in a chamber 4 formed by the housing 6 of the apparatus 1. The generally annular chamber 4 circumscribes a hand grip 8 moulded into the housing 6. By positioning the hand grip 8 inside the storage chamber 4 for the lead 2 the apparatus is made compact without the need for an additional handle outside the storage chamber 4. The position of the hand grip 8 can also be ergonomically favourable for controlling the lead length selection mechanism, as will be described in more detail below.

There will be described with respect to Figures 1 to 5 a first preferred embodiment of the invention. In this embodiment of the dog lead control apparatus, the lead 2 is wrapped around a storage reel formed by a lead track 10 and a drive cog 12. The lead track 10 is a continuous flexible band that has drive teeth 14 moulded on its inner surface. The drive teeth 14 mesh with corresponding teeth 16 on the outside of the drive cog 12 such that rotation of the drive cog 12 drives rotary motion of the lead track 10, and vice versa. Six runners 18 are mounted to be freely rotatable on axles 20 provided in the storage chamber 4 at locations spaced around the hand grip 8. The runners 18 engage with the inner surface of the lead track 10 and assist in its smooth running. This arrangement advantageously allows the lead 2 to be stored in a chamber 4 that does not match the annular periphery of the drive cog 12. Instead the lead track 10 wraps the lead 2 around in a chamber 4 that is generally pill-shaped with the drive cog 12 housed inside the chamber 4 at the front with the hand grip 8 behind. This allows the drive cog 12 to be made compact and enables the overall diameter of the apparatus 1 to be kept small.

Inside the drive cog 12 there is a retraction mechanism comprising a coiled flat spring 22 that is anchored at its inner end to a fixed spindle 24 that passes through the housing 6 from side to side. The outer end of the spring 22 is connected to the inside of the drive cog 12. The housing 6 includes a lead exit aperture 25 positioned to guide the lead 2 tangentially off the lead track 10 and drive cog 12.

As the lead 2 is pulled in tension, the lead track 10 reels off the lead 2 and rotates the drive cog 12 forward to create tension in the spring 22. If the tension in the lead 2 is not sufficient to overcome the force in the spring 22 then the spring 22 acts to rotate the drive cog 12 backward and reel the lead 2 back into the housing 6. Thus the lead 2 is automatically retracted in length depending on the pull of the dog on the lead.

The apparatus 1 includes a normal brake 26 which allows the user to pause the lead 2 or lock and stop the lead 2 at any length. The brake 26 comprises a brake spring 28 and a brake trigger 30. The tension spring 28 creates a sprung trigger 30. As seen from Figures 2 and 3, the spring 28 is held in tension between a detail in the side of the brake 26 and a corresponding feature in the housing 6. When the brake trigger 30 is pressed down the pawl arm of the brake 26 rotates forward to interface with large teeth 32 that are provided around the outside face of the drive cog 12. Engagement of the brake pawl 26 with the teeth 32 of the drive cog 12 stops the cog 12 from rotating, which stops the flexible track 10 and lead 2 from moving.

The tension in the brake spring 28 and the size of the brake teeth 32 on the drive cog 12 are chosen such that the force of the retraction spring 22 is not enough to wind the drive cog 12 backward when the brake 26 is fully applied. However, if pressure on the brake trigger 30 is released, allowing the pawl 26 to start lifting under the tension of the brake spring 28, then the retraction mechanism can start to wind the lead 2 back in to the housing 6 in a ratchet fashion. The meshing of the brake pawl 26 with the brake teeth 32 on the cog 12 ensure that the cog 12 cannot rotate forward to extend the lead 2 until the brake 26 has been completely released.

A handler can therefore use the brake trigger 30 to apply a fine degree of control on the extension and retraction of the lead 2.

The brake trigger 30 also allows the lead 2 to be locked at a particular length. The brake trigger 30 slides back and forth on a T-shaped runner 34 provided on top of the brake 26. The base of the trigger 30 is the same width as the corresponding aperture 35 in the housing 6 and thus it can not slide when not pressed. However, once the brake 26 is pressed down the top of the trigger 30 is the free to slide forward over the runner 34 onthe brake 26, wedging the trigger 30 under the housing 6 against the force of the brake spring 28 and therefore keeping the brake 26 engaged with the drive cog 12. To release the brake 26 when it is locked down, the trigger 30 must be pressed down and pulled back so that the trigger 30 can pop back out from the housing 6 and the brake 26 is released by the force of the spring 28.

An important part of the apparatus 1 is the mechanism that allows a user to select a maximum extension length for the lead. The selection mechanism comprises a one-way brake independent of the brake 26 described above. This one-way brake prevents the drive cog 12 from rotating forward and releasing the lead further once it is extended to a selected length, while backward rotation of the drive cog 12 and thus retraction of the lead 2 is still possible.

The selection mechanism comprises a length adjustment lever 36 rotatably connected to the two outer faces of the housing 6. The adjustment lever 36 passes across the front of the housing 6 and can easily be operated by the thumb of a hand gripping the apparatus 1. The main principle of the lead length selection mechanism is changing the rotation of the drive cog 12 when the lead 2 is being dispensed into a linear movement that can be controlled by the lever 36.

The length selection mechanism is arranged next to the drive cog 12 and connects to the drive cog 12 via a threaded gear wheel 38 and an interface gear 40 which interfaces with a geared internal face provided on one side of the drive cog 12, as is best seen from Figures 2 and 3. The interface gear 40 is solely used to reduce the amount of turns between the drive gear 12 and the threaded gear 38. The interface gear 40 is mounted on a pin (not shown) on the housing 6. Both of the gears 38, 40 are separated laterally from the drive spring 22 by a spring cover 23. The spring cover 23 has a central aperture through which the axle 44 of the threaded gear 38 passes through, thereby passing through into the fixed spindle 24 of the drive cog 12 in a coaxial arrangement to terminate against the opposite face of the housing 6.

Inside the fixed spindle 24 of the drive cog 12 there is provided a threaded wedge 42 that can shuttle back and forth on a thread provided by the axle 44 of the -13-threaded gear 38. The thread 44 passes from one side of the housing 6 to the other. When the lead 2 is pulled out and the drive cog 12 turns, the interface gear and the threaded gear 38 also turn, and the threaded wedge 42 travels along the thread 44 of the threaded gear 38. There are two pips 46 on the threaded wedge 42 which locate in two opposed grooves 48 running along the spindle 24 which the retraction spring 22 is anchored to. These pips 46 simple stop the threaded wedge 42 from rotating and allow it to travel back and forth on the inner thread 44.

In the length selection mechanism the rotating movement of the drive cog 12 has been changed into a linear movement made by the threaded wedge 42. By limiting how far the threaded wedge 42 can travel along the thread 44 it is therefore possible to limit forward rotation of the drive cog 12 and thus select how much lead 2 will be allowed to extend out of the housing 6. To limit the amount of travel of the threaded wedge 42, there is provided a second, adjustable wedge 50 positioned on the thread 44 of the threaded gear 38 at the opposite end of the thread 44 from the threaded wedge 42 and the gear 38.

As can be seen from Figures 4 and 5, the adjustable wedge 50 is operatively connected to the length adjustment lever 36 and can be turned on the thread 44 by up to 90 degrees by moving down the lever 36. When the lever 36 is horizontal, as shown in Figure 4, the adjustable wedge 50 is open and the threaded wedge 42 can travel all the way along the thread 44, allowing the drive cog 12 to rotate forward until all of the lead has been extended. When the lever 36 is vertical, as shown in Figure 5, the adjustable wedge 50 is moved round to a closed position and the threaded wedge 42 will now hit the adjustable wedge 50 as it moves across the thread 44, limiting the distance travelled by the threaded wedge 42 and thus the forward rotation of the drive cog 12 to limit the amount of lead 12 it is possible to extend out of the housing 6.

To allow multiple different lengths of lead 2 to be selected, the adjustable lever 36 can be set to one of four positions between horizontal and vertical. These positions are selected by bumping a pip 52 on the inside face of the adjustable lever 36 into one of four corresponding recesses (not shown) provided on the housing 6, around the split line of the two sides of the housing 6. Every time a different lever position is selected, the position of the adjustable wedge 50 is rotated to change the -14-distance that can be travelled by the threaded wedge 42 before the gears 38, 40 and drive cog 12 are prevented from further forward rotation. This therefore provides an adjustable one-way brake for the lead 2. However the lead 2 can still be retracted by the force of the drive spring 22, and whenever the drive cog 12 is wound backward by the spring 22 the gears 38, 40 are also moved back and the threaded wedge 42 travels back along its thread 44. The maximum linear position of the threaded wedge 42 on its thread 44 and hence the maximum extension length of the lead 2 can be adjusted at any time by clicking the lever 36 into a different position. The user therefore has the freedom to select a maximum extension length for the lead 2 depending on the environment where the dog is walking or the dog's behaviour.

Clean running of the lead 2 is aided by a retraction guide 52 provided in the lead exit aperture 25 in the front of the housing 6. The retraction guide 52 includes a tongue 54 that bears against the lead 2 as it passes through the aperture 25, thereby helping to ensure that the lead 2 is flat and not twisted when it is wound and on off the reel. Another benefit of the tongue shape 54 is that there is space for the lead 2 to move from side to side as it is reeled in and out from below the tongue 54, so the lead is not restricted in its movement and there is less risk of entanglement or jamming.

There will now be described with respect to Figures 6 to 8 a second preferred embodiment of the invention. In this embodiment of the dog lead control apparatus 101 the lead 102 is wrapped around a storage reel formed by a circular reel 110 that is driven by an inner cog 112. The lead 102 is therefore stored in an annular chamber 104 defined around the periphery of the reel 110, both circumscribing a hand grip 108 moulded into the housing 106. This apparatus 101 has a more circular geometry compared to the apparatus 1 shown in Figures 1 to 5, but necessarily has a larger circumference in order to store a lead 102 of the same length and thickness.

In the apparatus 101 of the second embodiment the principals of the drive mechanism for extending and retracting the lead, and of the main brake, are the same as in the first embodiment and thus will not be described again in detail. For example; it can be seen from Figure 8 that there is a coil spring 122 inside the drive cog 112 so as to urge the cog 112 and hence the lead reel 110 to rotate backward against the tension in the lead 102. The drive cog 112 is arranged eccentrically inside the lead reel 110 and the two wheels are meshed together by teeth. As regards the brake 126, it can also be seen that the brake trigger 130 is mounted on a spring 128 that biases the pawl of the brake 126 out of contact with the reel 110.

When the brake trigger 130 is pressed down, the pawl (hidden from view in the cross-section) engages with the teeth 132 provided around the outside face of the reel 110. This brake mechanism operates in the same way as is described above.

It can also be seen from Figure 6 that the apparatus 101 includes a retraction guide 152 with a tongue 154 that bears against the lead 102 as it is extended.

The main differences between the first and second embodiments relate to the gear mechanism that is used to apply the one-way brake when the lead is extended to a maximum selected length. Ft can be seen from Figure 8 that in the second embodiment there is provided a single gearwheel 138 that interfaces the drive cog 112 and the length selection mechanism. The gearwheel 138 has teeth that mesh with teeth on the drive cog 112 such that forward motion of one causes backward motion of the other, and vice versa. The gear wheel 138 is provided with a cam 142 mounted on the same axis so as to rotate together with the gear wheel 138. A stop 150 is moulded inside the housing 106 so as to contact the cam 142 as it rotates. The rotary position of the cam 142 relative to the stop 150 determines how far the gear wheel 138 can rotate, and thus how many turns of the cog 112 and lead reel 110 are allowed, before the lead 102 is prevented from unreeling further.

The gear wheel 138 and the drive cog 112 are arranged in a ratio of 5:1. Therefore for a 60 mm reel 110, five revolutions releases one metre of lead 102 and rotates the gearwheel by 1/4 of a revolution.

The gear wheel 138 is connected through the housing 106 with a length selection dial 136 that can be seen in Figure 7. A coil spring (not shown) is positioned between the gear wheel and the dial 136 so that the dial is normally biased out of active engagement with the gear wheel 138. The length selection dial 136 is brought into engagement with the gear wheel 138 by pressing it towards the housing 6 and compressing the spring. Once engaged, the selection dial 136 can be turned to select one of three preset maximum extension lengths for the lead.

This turns the gear wheel 138 and its associated cam 142 by up to 1/4 of a -16-revolution. By adjusting the rotary position of the cam 142, there is changed the number of turns of the reel 110 before the cam 142 comes up against the stop 150.

Thus the drive cog 112 and the reel 110 are prevented from rotating forward once the selected maximum extension length for the lead has been reached.

As in the first embodiment, the one-way brake provided by the gear wheel 138, adjustable cam 142 and stop 150 does not interfere with the retraction spring 122 acting on the drive cog 112. If the dog on the lead 102 moves closer to its handler then any slack can be immediately retracted by the spring 122. Thus the lead can be freely extended and retracted, depending on the tension applied, up until it reaches its selected maximum extension length. The maximum extension length can be changed at any time by pressing in the dial 136 and rotating it to a different position.

Although there are described above two distinct embodiments, it will be appreciated that various features may be interchanged between the embodiments.

For example, the length selection mechanism described with respect to Figures 1 to could be used in the apparatus described with respect to Figures 6 to 8 instead, and vice versa. The two different arrangements for the lead track/reel could be swapped over without affecting the gear mechanism that enables a maximum extension length to be selected. The particular shape and form of the hand grip may also be varied beyond those shown in the accompanying Figures.

Furthermore, although the embodiments described above relate primarily to a dog lead apparatus, the invention is not limited to this and the apparatus could find use in controlling the lead for many different animals, including both domestic pets and wild animals under restraint. The apparatus could also be used to control a child rein, e.g. connected to a child harness.

Claims

Claims 1. Apparatus for controlling a lead comprising: an extendable lead and a storage reel for the lead, the lead being extended under tension by forward rotation of the reel; and retraction means arranged to urge the storage reel to rotate backward against the tension in the lead; the apparatus further comprising: means for selecting a maximum extension length for the lead, said selection means comprising a one-way brake preventing the storage reel from rotating forward and releasing the lead further once it is extended to the selected length.
2. Apparatus as claimed in claim 1, wherein the selection means enables a user to manually select a desired maximum extension length for the lead.
3. Apparatus as claimed in claim 1 or 2, wherein the selection means provides one or more preset maximum extension lengths for the lead.
4. Apparatus as claimed in claim 1, 2 or 3, wherein the selection means comprises a rotary selection switch that is manually activated to select a desired maximum extension length for the lead.
5. Apparatus as claimed in any preceding claim, wherein the one-way brake of the selection means comprises a gear mechanism coupled to the storage reel.
6. Apparatus as claimed in claim 5, wherein motion of the gear mechanism corresponding to forward rotation of the storage reel can be controlled depending on the extended length of the lead.
7. Apparatus as claimed in claim 5 or 6, wherein the gear mechanism comprises an adjustable stop.
8. Apparatus as claimed in claim 7, wherein the position of the adjustable stop can be adjusted to limit motion of the gear mechanism according to the maximum extension length selected.
9. Apparatus as claimed in claim 5 or 6, wherein the gear mechanism comprises an adjustable cam.
10. Apparatus as claimed in claim 9, wherein the position of the adjustable cam relative to a stop can be adjusted to limit motion of the gear mechanism according to the maximum extension length selected.
11 Apparatus as claimed in any of claims 5 to 10, wherein the gear mechanism comprises a gear wheel rotationally coupled to the storage reel.
12. Apparatus as claimed in claim 11, wherein the gear mechanism comprises a gear wheel rotationally coupled to the storage reel and a threaded gear follower, wherein the threaded gear follower moves linearly along the axis of the gear wheel according to rotation of the gearwheel until it meets an or the adjustable stop.
13. Apparatus as claimed in claim 12, wherein the linear position of the adjustable stop along the axis of the gear wheel can be adjusted to limit rotation of the gear wheel according to the maximum extension length selected.
14. Apparatus as claimed in claim 11, wherein the gear mechanism comprises a gear wheel rotationally coupled to the storage reel and an adjustable cam, wherein the adjustable cam rotates with the gear wheel until it meets a stop.
15. Apparatus as claimed in claim 14, wherein the rotary position of the adjustable cam relative to the gear wheel can be adjusted to limit rotation of the gear wheel according to the maximum extension length selected.
16. Apparatus as claimed in any preceding claim, further comprising brake means actuable in a mode of operation to prevent extension or retraction of the lead.
17. Apparatus as claimed in claim 16, wherein the brake means is arranged to act on the storage reel in said mode of operation to prevent the reel from rotating forward or backward.
18. Apparatus as claimed in claim 17, wherein the brake means comprises a pawl arranged to engage with teeth provided on the storage reel.
19. Apparatus as claimed in claim 18, wherein the brake means comprises a spring arranged to bias the pawl out of engagement with the storage reel.
20. Apparatus as claimed in claim 18 or 19, wherein the pawl of the brake means can be applied in another mode of operation to provide a ratchet mechanism preventing forward rotation of the storage reel.
21. Apparatus as claimed in any of claims 16 to 20, wherein the brake means comprises a lock.
22. Apparatus as claimed in claim 21, wherein the lock holds the brake means in a mode of operation wherein the storage reel is prevented from rotating forward or backward.
23. Apparatus as claimed in any preceding claim, wherein the lead is stored in a generally annular chamber circumscribing a hand grip for the apparatus.
24. Apparatus for controlling a lead comprising: an extendable lead and a storage reel for the lead, the lead being extended under tension by forward rotation of the reel; and retraction means arranged to urge the storage reel to rotate backward against the tension in the lead; wherein the lead is stored in a generally annular chamber circumscribing a hand grip for the apparatus.
25. Apparatus as claimed in claim 23, wherein the selection means is also provided in a space circumscribed by the lead storage chamber.
26. Apparatus as claimed in any preceding claim, wherein the storage reel comprises a rotational drive means operatively connected to the retraction means.

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27. Apparatus as claimed in claim 26, wherein the storage reel comprises a carrier for the lead that is rotated by the drive means.
28. Apparatus as claimed in claim 27, wherein the lead carrier runs in a or the chamber circumscribing a hand grip for the apparatus.
29. Apparatus as claimed in claim 27 or 28, wherein the lead carrier comprises a wheel or a generally annular track that is oval, oblong, elliptical, pill-shaped, kidney-shaped, tortuous or otherwise ring-shaped.
30. Apparatus as claimed in any preceding claim, wherein the retraction means comprises a flat coil spring.
31. Apparatus as claimed in any preceding claim, further comprising guide means to direct the lead from the storage reel as it is extended.
32. Apparatus as claimed in claim 31 wherein the guide means directs the lead tangentially from the storage reel
33. Apparatus as claimed in claim 31 or 32, wherein the guide means comprises a tongue arranged to bear against the surface of the lead as it is extended.
34. Apparatus as hereinbefore described with reference to the accompanying drawings.*::r: INTELLECTUAL . ... PROPERTY OFFICE Application No: GB 1010444.6 Examiner: Heather Webber Claims searched: 1 -23 Date of search: 14 October 2010 Patents Act 1977: Search Report under Section 17 Documents considered to be relevant: Category Relevant Identity of document and passage or figure of particular relevance to claims X 1, 2, 4 -6, US 3693596 A 9, 16 -19, (CROCE et al) see whole document and figures 21, 30 -X 1, 2, 4, 5, US 3853283 A 16 -19, (CROCE et al) see whole document and figures 21, 22, 30, 31 X 1 -3, 5 -US 2004/237907 Al 8, 11, 30, (MULLER) see whole document and figures 31, 32 X 1 at least US 2004/237906 Al (WAXMAN et al) see whole document and figures X 1 at least US 2006/272366 Al (KIM et al) see whole document and figures X 1 at least DE 20017028 Ui (BUSSE) see WPI abstract accession number: 2001-336713 [36] and figures Categories: X Document indicating lack of novelty or inventive A Document indicating technological background and/or state step of the art.Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of before the filing date of this invention.same category.& Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP, WO & US patent documents classified in the following areas of the UKCX: Worldwide search of patent documents classified in the following areas of the IPC AU1K; B65H The following online and other databases have been used in the preparation of this search report EPODOC, WPI Intellectual Property Office is an operating name of the Patent Office www.ipo.gov.uk *.:r: INTELLECTUAL . ... PROPERTY OFFICE International Classification: Subclass Subgroup Valid From B65H 0075/44 01/01/2006 AO1K 0027/00 01/01/2006 Intellectual Property Office is an operating name of the Patent Office www.ipo.gov.uk