TECHNICAL FIELD

[0001] The present disclosure relates to the field of assisted propulsion at swimming and diving and in particular to an electrified underwater propulsion device for use with diving flippers also called swim fins.

BACKGROUND

[0002] Swimming and diving in water requires quite large amounts of energy. It is tiring and, for scuba divers, under water transportation increases the oxygen

consumption which in turn reduces the time that the diver may stay under the surface. Scuba and snorkel divers as well as regular on-surface swimmers often use diving flippers or swim fins for facilitating the transportation and to increase the speed.

[0003] There have also been developed several different motorised propulsion devices intended to assist at in- and underwater transportation. Some such known propulsion devices are hand held which reduces the diver’s ability to use the hands for other purposes. Some other are designed to be fastened to the torso, the arms or the legs of the diver/swimmer. The latter devices often are bulky and impede manoeuvrability and quick directional changes.

[0004] US 6,341,993 Bi discloses an underwater propulsion device constituted by a motorized swim fin. The device comprises a boot with a paddle extending from a toe portion of the boot. A tubular passageway way is arranged in the paddle and a power driven shaft with a propeller is arranged in the passageway for pushing water from an inlet to an outlet of the passageway.

SUMMARY

[0005] One object of the present disclosure is to provide an enhanced underwater propulsion device.

[0006] Another object is to provide such a propulsion device which may be used with standard diving flippers.

[0007] A further object is to provide such a propulsion device which readily may be mounted to a traditional diving flipper. [0008] Yet another object is to provide such a propulsion device which allows easy dismounting from the diving flipper for using the flipper in a traditional manner.

[0009] A still further object is to provide such a propulsion device which allows the flipper to be used in a traditional manner also when the propulsion device is mounted thereto.

[0010] Another object is to provide such a propulsion device which allows good manoeuvrability as well as quick and easy directional changes.

[0011] A further object is to provide such a propulsion device which is simple in its construction and which may be manufactured at a comparatively low cost.

[0012] These and other objects are achieved by an underwater propulsion device as set out in appended claim 1. The underwater propulsion device comprises a propulsion unit and a mounting unit. The propulsion unit is mounted to the mounting unit and comprises an electrically driven propeller. The mounting unit is arranged to be removably fixed to a diving flipper.

[0013] The underwater propulsion device being mountable to a regular or standard diving flipper affords for a number of advantages. Divers and swimmers normally have their own flippers which have been selected with great care for optimal performance and comfort. Parameters which are taken into consideration when choosing the best flippers include the size of the portion holding the foot, the length and other dimensions of the paddle. The material of the foot and paddle portions as well as its stiffness and flexibility are important. The colour and other design features of the flipper are often also taken into consideration. Hence both for professional divers and for hobbyists it is important that the diving flippers are carefully selected and there exist a great variety of different variants in order to suit every diver’s needs and taste. The mountable propulsion device of this disclosure thus allows for that the user may still use his/her favourite flippers while adding on an additional motorized propulsion functionality.

[0014] Additionally, rental shops for water sports equipment need only to keep a limited number of identical propulsion devices in stock. A pair of these may then be combined with any of the different diving flippers already in stock or with the rental customer’s own flippers, in order to offer the best combination for each customer. This allows for an important saving of costs for the shop owner and, in the end, also for the rental customer. [0015] The fact that the propulsion device, in use, is mounted to the diving flippers also allows for that the user may use his or her hands for other purposes than holding the propulsion device. It has also proven that such mounting to the flippers greatly improves the manoeuvrability and the ability to quickly change direction in comparison to previous underwater propulsion devices which are hand held or attached to the torso, the arms or the legs of the user.

[0016] The mountable propulsion device according to the present disclosure may be designed and constructed essentially less complicated and with fewer constituent components in comparison with the motorized swim fin according to US 6,341,993 Bi. This greatly reduces the time and cost needed for manufacturing.

[0017] At one embodiment the mounting unit may comprise two legs, each leg being arranged to at least partly surround and to contact a respective longitudinal side rib of the diving flipper. Most diving flippers presently available on the market exhibit stiffening longitudinal side ribs which extend along each peripheral edge of the paddle portion, from the foot portion towards or to the longitudinal free end of the paddle portion. The two legs of the propulsion device’s mounting unit allow for that these ribs may be utilized for a secure removable fixation of the device to the flipper.

[0018] The mounting device may comprise at least one resilient member arranged to urge said legs into contact with the respective longitudinal side rib. This facilitates the mounting operation and enhances fixation to the flipper.

[0019] The mounting unit may comprise at least one support member arranged to bear against the diving flipper, at a side which is opposite to the side to which the legs are urged into contact with the longitudinal side ribs. This further enhances the fixation.

[0020] The mounting unit may comprise a base having a front end, a rear end, an upper side and a lower side, the propulsion unit being fixed to the upper side of the base, and the two legs may be arranged to extend downwardly from a respective lateral side edge of the base. By this means a sturdy and reliable mounting unit is achieved in a simple manner.

[0021] The underwater propulsion device may comprise a quick release fastener which comprises a first part which is arranged to be permanently fixed to the diving flipper and a second part which is fixed to the mounting unit, wherein the first and second parts comprise cooperating snap lock means. By this means, secure fixation to the flipper is further enhanced in a simple and cost effective manner.

[0022] Said second part may be hingedly connected to the base. Such a hinge functionality applied to the mounting unit allows for that the paddle portion of the flipper may flex in an almost normal manner. This in turn enhances the ability to use the flippers in a traditional manner whether or not the propulsion unit is activated.

[0023] The at least one resilient member may comprise a leaf spring. By this means the desired urging of the legs is accomplished in a reliable and simple manner.

[0024] Alternatively or in combination, the at least one resilient member may comprise a torsional spring formed integral with one of said legs. This allows for alternative embodiments and enhances the fixation of the propulsion device.

[0025] The legs and/or the support member may be provided with a low friction material for decreasing the friction between the legs and the longitudinal side ribs. At some embodiments this may increase the flipper’s ability to flex in a normal manner, thereby enhancing traditional use of the flippers.

[0026] Alternatively the legs may be provided with a high friction material for increasing the friction between the legs and the longitudinal side ribs of the diving flipper. At some embodiments such increased friction may enhance the fixation of the legs to the ribs while still allowing the flipper’s paddle portion to flex normally.

[0027] Further objects and advantages of the underwater propulsion device will appear from the following detailed description and the appended claims.

[0028] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Aspects and embodiments are now described, by way of example, with refer ence to the accompanying drawings, in which: [0030] Fig. la is a top view of a traditional diving flipper which may be used with the underwater propulsion device. Fig. lb is a section along A-A in fig. la.

[0031] Fig 2 is a side view of an underwater propulsion device according to a first embodiment when mounted to a diving flipper worn by a user.

[0032] Fig. 3 is a front view of the underwater propulsion device shown in fig. 1.

[0033] Fig. 4 is a top view of the underwater propulsion device shown in fig. 1.

[0034] Fig. 5 is a top view of an underwater propulsion device according to a second embodiment when mounted to a diving flipper.

[0035] Fig. 6 is a side view, partly in section along B-B in fig 5 of the underwater propulsion device shown in fig. 5.

[0036] Fig. 7 is a side view of the underwater propulsion device shown in fig. 5.

[0037] Fig. 8 is a front view of the underwater propulsion device shown in fig. 5.

[0038] Fig. 9 is a top view of the underwater propulsion device shown in fig. 5.

DETAILED DESCRIPTION

[0039] The aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which certain

embodiments of the invention are shown.

[0040] These aspects may, however, be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and to fully convey the scope of all aspects of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.

[0041] Fig. la illustrates a conventional diving flipper 1 or swim fin. The diving flipper has an upper side la shown in fig. la and an opposite lower side lb. It comprises a rear foot portion 2 with a cavity 2a for receiving a foot of the user. The foot portion 2a exhibits a front opening 2b through which the toes of the wearer protrudes. A paddle portion 3 extends forwardly to a free end 3a from the foot portion 2. The width of the paddle portion 3 increases from the foot portion 2 towards the free end 3a. A stiffening rib 4, 5 extends longitudinally along each peripheral side of the paddle portion 3. The ribs 4, 5 extend from essentially a mid section of the foot portion 2 to the free end 3a. Since the width of the paddle portion 3 increases in the forward direction, the ribs 4, 5 diverge in the forward direction. The vertical thickness of the ribs 4, 5 varies along the longitudinal length, such that is exhibits a maximum at a longitudinal mid portion and a minimum at the respective longitudinal ends. The ribs 4, 5 are essentially thicker than the intermediate portion of the paddle portion 3, arranged between the ribs 4, 5, such that the ribs protrude upwardly and downwardly from this intermediate portion. The diving flipper 1 is made of a flexible material such as rubber. The foot portion 2 is essentially softer and more flexible that the paddle portion 3, such that the walls surrounding the cavity 2a may be depressed. Even though the paddle portion 3 is stiffer than the foot portion 2, it flexes upwards and downwards when the user paddles his or her feet during transportation in the water.

[0042] A first embodiment of the underwater propulsion device 10 will now be described with reference to figs. 2a - 4. The propulsion device 10 comprises a propulsion unit 11 and a mounting unit 12 arranged to be mounted to a diving flipper 1 of the general kind illustrated in figs la, lb. The propulsion unit 11 comprises a cylindrical housing 13 which receives an electrical motor 14 having a propeller 15 fixed on its rotating axle (not shown). In the figures the propulsion unit 11 is schematically illustrated. It also comprises not shown means for fixing the motor 14 to the housing 13. An electrical cable 16 which is connected to the motor for power supply and control extends from the propulsion unit 11. The cable is also connected to a power supply (not shown) such as a rechargeable battery pack which may be worn e.g. at the leg or torso of the user and to a control device (not shown) which e.g. may be integrated with the battery pack or which may be worn at an arm, wrist or hand of the user. Alternatively, the control unit may be wirelessly connected to the motor. At a further alternative the battery pack may be fixed to or made integral with the propulsion unit or the mounting unit. When such embodiments are combined with a wireless control unit an important advantage of not requiring any external cables is achieved. The propulsion unit may however be realized in many different manners, as readily realized by the person skilled in the art.

[0043] The propulsion unit 11 is fixed to the upper side of the mounting unit 12. The mounting unit 12 comprises a plate shaped base 17. The base 17 has a rear end 17a, a front end 17b, a lower side 17c facing the flipper 1 when mounted and an opposite upper side i7d. A pair of legs 18, 19 extend downwardly from a respective and mutually opposite side edge of the base 17, at its rear end 17a. As best seen in fig. 3, each leg 18, 19 comprises a downwardly projecting stem 18a, 19a and a curved, inwardly projecting lug 18b, 19b. The legs 18, 19 are connected to the base 17 by a respective curved connecting portion 18c, 19c. The lugs 18b, 19b and the connecting portions 18c, 19c are arranged to receive and partially surround a respective rib 4, 5 of the flipper 1.

[0044] The mounting unit 12 further comprises two resilient members, here in the form of leaf springs 20, 21. One end of each leaf spring is fixed to the lower side of the base 17, centrally and in proximity to the rear end 17a. The leaf springs 20, 21 extend downwardly and outwardly towards a respective leg 18, 19. The leaf springs 20, 21 are arranged to exert a downward force when compressed upwardly.

[0045] The mounting unit 12 also comprises a hinge mechanism 22 arranged at the front end 17b of the base 17. A support member formed by a quick release fastener 23 is hingedly connected to the base 17 by means of the hinge mechanism 22. The quick release fastener 23 comprises a first part 23a which is arranged to be permanently fixed to the paddle portion 3 of the flipper 1 and a second part 23b which is hingedly connected to the base 17. The first part may e.g. be fixed to the paddle portion 3 by gluing. Alternatively or in combination the first part may comprise a first sub-part comprising a treaded stem and a circular flange and a second sub-part comprising a circular disc with a threaded hole for receiving the stem. For fixing the first part 23a to the paddle portion 3, the stem is pushed or screwed from below to penetrate the paddle portion until the flange contacts the lower side of the paddle portion and the stem protrudes above the upper side of the paddle portion. Thereafter the disc is screwed onto the stem for fixing the first part to the paddle portion 3. The first 23a and second 23b parts are arranged to be mutually connected by being pushed together and disconnected by pulling a knob on the second part 23b. Such quick release fasteners are well known in the art. One example which may be used is sold under the trade name LOXX® but other quick release fasteners may also be used.

[0046] Mounting of the underwater propulsion device 10 to the diving flipper 1 will now be explained. First the base 17 is slided onto the diving flipper, from the narrower rear foot portion forwardly. The flexible walls surrounding the cavity 2a, are then compressed such that the mounting unit 12 may be advanced with the two legs 18 sliding along the ribs 4, 5. The mounting unit 12 is displaced forwardly until the legs 18, 19 have passed the foot portion 2 and have reached a portion of the paddle portion 3 approximately where the ribs 4, 5 exhibit the largest vertical thickness. At this position, the first part 23a of the quick release fastener 23 is fixed to the paddle portion 3 of the flipper 1, as described above. The second part 23b of the quick release fastener 23 is then aligned with the first part 23a and the two parts 23a, 23b may be pushed together for mutual fixation. The mounting unit 12 has now assumed its correct mounting position on the diving flipper 1. In this position, the leaf springs 20, 21 are compressed and their free ends make contact with the upper side la of the paddle portion 3. The force exerted by the leaf springs 20, 21 urges the lugs 18b, 19b into contact with the lower edges of a respective rib 4, 5 Thereby, the mounting unit 12 has been securely mounted to the diving flipper 1.

[0047] In use at forward transportation, the diver stretches his/her ankles such that the rotational axis of the motor 14 is directed generally in parallel with the user’s longitudinal direction. The propeller 15 then pushes water backwardly to thereby propel the user forwardly. For turning in either sideways direction, upwards or downwards the user may easily angel his/her feet in a corresponding direction for excellent and quick control of the transportation direction. Activation, deactivation and speed control of the motor is readily achieved e.g. by pushing corresponding push buttons on the control device (not shown).

[0048] Whether or not the motor is activated, the user may also use the diving flippers 1 in a ordinary manner by paddling his/her feet. The water resistance will then urge the paddle portions to flex upwardly and downwardly from the position shown in fig. 2. Such flexing is allowed grace to the hinge mechanism 22 and the ability of the legs 18, 19 and the lugs 18b , 19b to slide along the respective rib 4, 5. For increasing this sliding function and enhancing flexing of the paddle portion 3, the lugs 18b, 19b and/or the stems 18a, 19a of the legs 18, 19 may be formed of or comprise a low friction material such as polyethylene (PE), polytetrafluoroethylene (PTFE) or the like

[0049] A second embodiment will now be described with reference to figs. 5 - 9.

Also at this embodiment the underwater propulsion device 100 comprises a propulsion unit 111 which is fixed to the upper side of a mounting unit 112. The propulsion unit 111 is identical with the propulsion unit according to the first embodiment and it is not described further here.

[0050] The mounting unit 112 comprises a generally plate shaped base 117 having a rear end 117a, a front end 117b, a lower side 117c and an upper side ii7d. At the front end 117b, the base exhibits a downwardly protruding curved support member 123 arranged to make contact with the upper side of the paddle portion 3 of the flipper 1. The support member 123 may be formed of or comprise a low friction material for enhancing sliding of the support member 123 relative to the paddle portion 3. The curvature of the support member 123 also contributes to decreasing the friction. At its rear end 117a, the base exhibits two tubular spring holders 122a, 122b, arranged at a respective side edge of the base 117. Each spring holder 122a, 122b receives a torsional spring 118, 119.

[0051] Each torsional spring 118, 119 comprises a first support section 118a which is supported on the upper side ii7d of the base 117. A torsional section 118b, 119b extends perpendicularly outwards from the rear end of the respective support section 118a, 119a and is received in and held by the tubular spring holder 122a, 122b. Each torsional spring further comprises a leg 118c, 119c which extends perpendicularly from the outer end of the respective torsional section 118b, 119b. As represented by solid lines in fig 7, the legs 118c, 119c are arranged generally in parallel with the support sections 118a, 119a when the torsional springs 118, 119 are relaxed. At the free end of each leg 118c, 119c, a lug n8d, ii9d projects inwardly. Each lug n8d, ii9d comprises a bent portion of the spring 118, 119 and a sleeve n8e, ii9e which receives the bent portion. The sleeves n8e, H9e may be formed of or comprise a high friction material for preventing relative movement between the holding unit 112 and the paddle portion 3 when mounted.

[0052] The base further comprises two downwardly projecting contact tabs 124a, 124b. The contact tabs 124a, 124b may be formed sharp such that they penetrate somewhat into the upper side of the paddle portion for secure fixation of the holding unit 112 to the paddle portion 3. In the latter case it may be desirable to minimize the friction between the lugs n8d, ii9d and the ribs 4, 5. The sleeves n8e, ii9e may then comprise a low friction material and/or be arranged rotatable relative to the bent portions.

[0053] When mounting the underwater propulsion device 100 to the diving flipper 1, the, the legs 118c, 119c are first tensioned by pivoting the legs 118c, 119c downwards and backwards as indicated by the dashed lines in fig, 7. Thereafter the holding unit is slid onto the flipper 1 from behind. As at the first embodiment, the flexibility of the walls enclosing the cavity 2a allows the holding portion with the base 117, the legs 118c, 119c and the lugs n8d, H9d to pass the foot portion 2 of the flipper. When the mounting unit has reached the position illustrated in figs 5 and 6, where the legs are arranged generally at a position where the ribs 4, 5 exhibit their largest vertical thickness, the legs 118c,

119c are released. The spring force will then urge the legs 118c, 119c, forwardly such that the lugs n8d, ii9d are pressed against the lower edge of the ribs 4, 5. Simultaneously the contact tabs 124a, 124b are pressed against the upper side of the paddle portion and if the are sharp, they may somewhat penetrate into the upper surface of the paddle portion 3. The torsional spring force will also exert a torque onto the base 117 such that the support member 123 is pressed in to contact with the upper side of the paddle portion. By this means the underwater propulsion device according to the second embodiment has been securely fixed to the diving paddle.

[0054] The propulsion device according to the second embodiment is activated, deactivated, controlled and maneuvered generally in the same manner as the propulsion deice according to the first embodiment.

[0055] When the flippers 1 are to be used in a traditional manner, with the propulsion devices mounted, the resiliency of the torsional spring allows the base to pivot somewhat around the contact tabs 122a, 122b relative to the paddle portion. This in combination with that the support member 123 is arranged to slide on the upper surface of the paddle portion 3 allows the paddle portion 3 to flex upwardly and downwardly during paddling of the users feet.

[0056] In both the above described embodiments the base may be formed of stainless steel, plastic or any other suitable material.

[0057] The resilient member may comprise a helical compression spring or any other suitable resilient member or material, instead of or in combination with a leaf spring or a torsion spring as described above.

[0058] In the examples shown and described above the diving flipper or swim fin is of the type comprising a cavity arranged to receive a foot of the user. Naturally however the flipper may be of other types, e.g. having a heel strap which is tightened around the heel of the user. It is also possible to use the propulsion device together with so called solo flippers where both feet of the user are fixed to a single paddle.

[0059] The aspects of the present disclosure have mainly been described above with reference to a few embodiments and examples thereof. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.