US 20070226865 A1
Arrangement for securing a hearing protector to a helmet, which arrangement comprises a cap holder piece (102) and a helmet piece (101). The cap holder piece contains a rotary plate (103), a bistable element (104) and a cap holder element (105), which is secured by means of the bistable element to the rotary plate to allow a hearing protection, secured to the cap holder element, to take up a tilted out and a tilted in position relative to the rotary plate. The helmet piece comprises means (112, 112′) of attachment to a helmet and a receiving piece (111), in which the rotary plate is secured, able to turn about an axis of rotation, which receiving piece includes a resilient tongue (113) essentially parallel to the axis of rotation and a first stop piece (116) which, under the action of the resilient tongue and in cooperation with a second stop piece (132) arranged on the rotary plate, releasably maintains the rotary plate in a first rotational position relative to the receiving piece. To prevent the cap holder piece from accidentally leaving the first rotational position, the arrangement includes a first projection (119) extending from the receiving piece essentially parallel to the axis of rotation, which in the first rotational position limits the motion of the rotary plate toward the resilient tongue by thrusting against the cap holder piece.
1. Arrangement for securing a hearing protector to a helmet, which arrangement comprises a cap holder piece (102) and a helmet piece (101), wherein
the cap holder piece contains a rotary plate (103), a bistable element (104) and a cap holder element (105), which is secured by means of the bistable element to the rotary plate to allow a hearing protection, secured to the cap holder element, to take up a tilted out and a tilted in position relative to the rotary plate, and
the helmet piece comprises means (112, 112′) for the attachment to a helmet and a receiving piece (111), in which the rotary plate is secured, pivotal about an axis of rotation, which receiving piece includes a tongue (113) which is resilient in a direction essentially parallel to the axis of rotation and a first stop piece (116) which, under the action of the resilient tongue and in cooperation with a second stop piece (132) arranged on the rotary plate, releasably maintains the rotary plate in a first rotational position relative to the receiving piece, characterized by
a first projection (119) extending from the receiving piece essentially parallel to the axis of rotation, which in the first rotational position limits the motion of the rotary plate toward the resilient tongue by bearing against the cap holder piece.
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The invention concerns an arrangement for securing a hearing protector to a helmet according to the preamble of patent claim 1. The invention also concerns a helmet with such an arrangement.
Nowadays, thanks to laws and regulations, many work situations require the employer to provide both a protective helmet and hearing protection to guard against various risks to the personnel during their work. One example is felling of trees with a chain saw. Most of the manufacturers of protective helmets have therefore adapted the configuration of the helmet as a standard model so that hearing protection can be attached to the helmet in that there is a slot or the like in the edge of the helmet on either side above the position of the ear. The hearing protection for the helmet is then provided with a helmet part that can be attached to the helmet in the slot, for example, by a snap fastener.
The hearing protection is worn during work in a protecting position or a working position, in which the caps of the hearing protection lie tightly against the user's head around the ears. Besides being worn in the working position, it should also be possible to move the caps into a resting position when the protection is not needed at the moment, e.g., during a work break. It is therefore desirable for the caps to be moved into a resting position without having to remove the hearing protection from the helmet. One such commonly occurring position of rest is taken up by rotating the ear caps backward and upward so that they are placed and remain outside of the helmet. In order for the caps to pass the edge of the helmet and take up the downward rotated position, it is often necessary to first move them into a tilted-out position just outside the ears. It is advantageous to move the ear caps into and maintain them in the tilted-out position, e.g., to make possible a short conversation while working.
Different helmet manufacturers use different slots or other elements to enable the fastening of the hearing protection to the helmet. It is therefore desirable for the hearing protection to have easily replaceable parts or adapters which fit the slots, etc., of the different helmet manufacturers. In this way, the very same hearing protection can be easily used for helmets of different brand.
2. Prior Art
As appears most clearly from
The helmet piece 1 contains a receiving piece 11 and an elastic fixation tongue 12 projecting downward from the receiving piece. The fixation tongue 12 is configured to snap into a slot formed in a helmet (not shown).
The rotary plate 3 is held and able to rotate in the receiving piece 11 in that the annular flange 31 of the rotary plate is inserted beneath the radially inward projecting flange 14 of the receiving piece. The projecting flange 17 of the resilient tongue 13 thus engages with the radially inward pointing cylindrical surface on the annular flange 31. The elasticity of the resilient tongue 13 allows the annular flange of the rotary plate 3 to engage and disengage from this rotational fastening by a snap action. The rotary plate 3 is inserted into and removed from the receiving piece 1 by a relative displacement in the vertical direction.
One problem with the above described known arrangement, however, is an inability to maintain the cap holder piece in the resting position. The force of gravity acting on the hearing protection and the lever arm, defined by the distance between the hearing protection and the axis of rotation of the rotary plate, produces a torque which strives to disengage the first and second stop from each other. Studies have shown that the hearing protection can be subjected to forces amounting to around 5-8 G, for example, when the user is walking on a stairway. The two stops can then become disengaged from each other, whereupon the cap holder piece with the hearing protection rotates downward from its resting position. This is often perceived as an annoyance by the user. To prevent such a downward rotation, the user might tilt in the cap holder piece in the upward rotated resting position so that the bistable leaf spring presses the hearing protection against the helmet shell. This results in relatively large forces, for example, at the fastening of the helmet piece in the helmet, which are liable to damage the helmet and/or the helmet piece of the arrangement.
Protective helmets can be made from ABS, for example. More recently, PE has also come to be used for manufacture of protective helmets. Due to the lower shape stability of PE, some of the problems connected with the above described known arrangement are even more serious when using protective helmets made of PE.
One purpose of the present invention is therefore to provide an improved arrangement for fastening of a hearing protection to a helmet.
Another purpose is to provide an arrangement which leads to a more secure retention of the hearing protection in a resting position rotated upward outside the helmet.
Furthermore, one purpose is to provide an arrangement which reduces the risk of damage to the helmet and the arrangement.
Yet another purpose is to provide an arrangement which reduces the problems arising when used on helmets made from PE.
One further purpose is to provide an arrangement which is reliable, durable, and easy to use.
A further purpose is to provide an arrangement comprising a limited number of constituent parts, and which is relatively simple and cheap to make.
These and other purposes are achieved with an arrangement of the kind indicated in the preamble of patent claim 1, which arrangement has the special technical features indicated in the characterizing passage of the claim.
The invention is based on the insight that the above described problem with swinging down from the resting position in the previously known arrangement is caused by the resilient tongue giving way and bending in toward the helmet when the first and second stops are pressed together if the cap holder piece in the resting position is subjected to a force which strives to turn the cap holder piece into the working position. Since the stops are pressed together during the turning, the rotary plate is twisted about a horizontal axis which is perpendicular to the axis of rotation of the rotary plate. In this process, the lower part of the rotary plate with the second stop piece is pressed in the outward direction, from the first stop piece on the receiving piece, and the upper part of the rotary plate diametrically opposite the second stop is pressed inward toward the resilient tongue. Due to the elasticity of the tongue, it allows this twisting or slanting of the rotary plate to occur, whereupon the second stop loses its engagement with the first stop and can move past it. Yet the resilient tongue has to have a certain elasticity in order to let the rotary plate of the cap holder piece snap in place and be released from the receiving piece of the helmet piece.
According to the invention, this problem is solved with a projection protruding from the receiving piece essentially parallel to the axis of rotation. The projection is arranged on the receiving piece so that, at least in the resting position, it limits or prevents the movement of the rotary plate inward towards the resilient tongue by bearing against some portion of the cap holder piece. In this way, the slanting or twisting about a horizontal axis which is perpendicular to the axis of rotation of the rotary plate is limited or prevented in the resting position. The second stop is thus not able to become disengaged from the first stop, unless a relatively large torque is applied to the cap holder piece in the direction towards the working position.
The projection is conveniently arranged so that in the resting position it prevents a slanting of the rotary plate by thrusting against the bistable element projecting from the rotary plate. In this way, the projection can be placed radially outside the rotary plate, so that the rotary motion of the rotary plate about the axis of rotation is not prevented.
The rotary plate advisedly will have a third stop piece which, engaging with the first stop piece on the receiving piece, defines a second resting position which is reached by turning in the opposite direction as compared to the first resting position. The arrangement will then have a second projection to prevent slanting of the rotary plate in the second resting position. The arrangement can then be used on both sides of the helmet and at the same time allow the cap holder piece to take up a stable backward-turned resting position in either case, by clockwise or counterclockwise rotation, respectively. In such a case, the second projection is also advisedly arranged so as to prevent a slanting of the rotary plate by thrusting against the bistable element.
The first and second projection can either be formed as separate elements or as a continuous projection. In this way, one has freedom of choice in the configuration which is most suitable in terms of manufacturing technology, strength, esthetic or other reasons.
The rotary plate is advisedly secured releasably in the receiving piece by snap action under the influence of the resilient tongue. This allows for a simple replacement of the helmet piece so that the very same cap holder piece can be used for helmets with different types and shapes of fasteners for the hearing protection by varying the helmet piece.
The means of attachment of the helmet piece to a helmet advisedly include at least one flexible male part for separable snap fastening to a corresponding female part on the helmet. In this way, a simple fastening and removal of the arrangement from the helmet is made possible, which means that the very same arrangement can be used for different helmets.
The invention also involves a helmet containing such an arrangement.
Further properties and advantages of the arrangement and the helmet according to the invention shall appear from the following detailed description and the patent claims.
The following provides a detailed description of sample embodiments with regard to the drawings, where:
The following describes two sample embodiments of the invention with regard to
The arrangements according to the invention, shown in
The helmet piece 101 contains a receiving piece 111 and an elastic fixation tongue 112, projecting downward from the receiving piece. The fixation tongue 112 is configured as a male part and it contains two outer tongue pieces 112 a, 112 b and a central flexible tongue piece 112 c with a snap hook for fastening to a corresponding female part in the form of a fixation slot which is arranged in the helmet.
The receiving piece 111 of the helmet piece contains an elastically resilient tongue 113 with a circular-arc flange 117 projecting forward (to the left in
In the embodiment shown in
Referring in particular to
As is shown most clearly by
As is clearly shown in
It should be noted that the projection 119 prevents a slanting of the rotary plate 103 only when the leaf spring 104 is placed in front of the projection and the cap holder piece thus rotates to the resting position. When the cap holder piece is in the working position, for example, or some other rotational position, the projection 119 does not affect the movement of the rotary plate. It is therefore possible, for example when the rotary plate is in the rotational position corresponding to the working position, to fasten or remove the rotary plate and the cap holder piece from the receiving piece and the helmet piece, thanks to the elasticity of the resilient tongue.
As shown by
Two sample embodiments of the invention have been described above. However, it is clear that the invention is not limited to the above-described embodiments, but rather it can be varied freely within the framework of the following patent claims. For example, the means of fastening the arrangement to a helmet which are arranged on the helmet piece can take on a number of different forms in order to fit different helmets on the market. The cap holder piece, of course, can also be variously shaped or replaced by different cap holder elements in order to fit different hearing protection devices occurring on the market.