Abstract:
A fastening adapter for fastening protectors to a helmet or other headgear includes a body part, a housing connected to the body part, at least one fastening device of the body part adapted to be fitted through a hole arranged in a wall of the helmet, at least one fastening device locking device for locking the fastening device and for pressing the body part onto the wall, which fastening device includes rotation prevention devices, to prevent the body part from rotating in relation to the wall.

Description:
TECHNICAL FIELD 
     This invention relates to a fastening adapter for fastening a protector, such as a hearing protector (or eye/face protector), to a helmet or other headgear. 
     BACKGROUND OF THE INVENTION 
     Usually various kinds of protectors, such as hearing protectors, are used in connection with safety helmets made from plastic. In some (slotted) helmets, there are existing pre-fastening devices for fastening protectors. In such cases, the attachment of hearing protectors, for example, is relatively simple. However, the attachment of protectors to a general-purpose (non-slotted) helmet without pre-fastening devices is very much more difficult and indeed sometimes impossible. 
     In one known protector fastening adapter intended for a general-purpose helmet, the body part is fastened to the helmet with two bolts. For this purpose, two holes must be machined in the helmet. The body part fastened to the helmet is then set rotatably in a housing, to which the actual hearing protector is attached. The installation of the fastening adapter requires tools, due to the nuts and bolts, which makes the attachment more difficult. In addition, the nuts and the ends of the bolts protrude considerably inside the helmet. This can create a risk of injury to the user of the helmet, in the form of a bruising or an electrical shock. It is also difficult to position the holes by eye. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to create a simpler, more versatile, and easier to install fastening adapter for fastening protectors to a helmet or other headgear. 
     The present invention provides a fastening adapter for fastening protectors, such as hearing and/or face shield protectors, to a helmet or other headgear. The fastening adapter includes a body part to be attached to the helmet or headgear, and a housing connected to the body part and supporting the protector. At least one fastening device of the body part is fitted through a hole arranged in a wall of the helmet or headgear, and at least one fastening device locking device on the opposite side of the wall in relation to the body part for locking the fastening device and for pressing the body part onto the wall. The fastening device includes rotation prevention devices, to prevent body part from rotating in relation to the wall. 
     The fastening device is in two parts, both of which fastening devices are pins that extend through wall and which are set at a distance from each other. The first fastening device comprises a protrusion that forms part of body part and the second fastening device comprises an axle pin forming part of housing, which extends through both body part and wall, and to which axle pin locking device is intended to be fitted. 
     The fastening adapter includes a series of pairs of locking devices forming locks for different wall thicknesses. The series forming part of the fastening adapter has 2-6, most preferably 3-5 pairs of locking devices. In each lock of the series forming part, there is a hole for fastening the device to the bottom surface of which is at an angle in the longitudinal direction of the lock in relation to the base of the lock to be set against wall. The thickness of the lock tongue lying in the holes varies, the interval of variation being 2-5 mm, most preferably 2.5-4.5 mm, on the bottom surface of the hole. 
     Each of the locks forming part of the series is made from the same material as the fastening device. In the locking device there is a slot for attaching the locking device to the protrusion. At the end of the axle pin belonging to the housing there is a groove around the entire circumference of the axle pin for attaching the locking device. The depth of the groove is parallel to the radius of the axle pin and corresponds essentially to the dimensions of the locking device. 
     The locking device is intended to be set in the groove at essentially right angles to the axle pin by pressing it. The fastening adapter includes a jig for drilling holes in the aforesaid wall. The two drilling holes in the jig are set at the same distance from one another as the axle pin is from the protrusion. The first hole in the jig corresponds to the diameter of the protrusion and the second hole in the jig corresponds to the diameter of the axle pin. There is a measuring stick at the end of the jig with the first hole for positioning the jig in relation to the lower edge of the wall. 
     The fastening devices of a fastening adapter according to the invention are formed by the structural components of the fastening adapter. Thus separate fasteners, made form metal for example, are not required. In addition, the fastening adapter can be installed without tools, after holes have been drilled. The parts of the fastening adapter remaining inside the helmet are short and do not have detrimental protrusions. In addition, the locking device of the fastening member acts against a large surface area of the wall of the helmet. Further, the fastening adapter can be used to attach hearing protectors or a protection visor, or both simultaneously. The fastening adapter according to the invention can also be fitted in connection with a headband or any other construction supported by the head. 
     These and other features and advantages of the invention are described in greater detail in the following detailed description with reference to the accompanying drawings showing some embodiments of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 shows a fastening adapter fastened to the helmet, fastening both a hearing protector and a visor; 
     FIGS. 2 a - 2   f  show the stages of the fastening adapter being attached to the side of the helmet; 
     FIG. 3 shows the parts of the fastening adapter, without the lock; 
     FIG. 4 shows the parts of FIG. 3 seen from the other side; 
     FIG. 5 shows the series formed by the locks used in the fastening adapter; 
     FIG. 6 shows a variation of the fastening adapter in FIG. 1 in a headband; and 
     FIG. 7 shows another embodiment of the fastening adapter according to the invention, in cross-section. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following description, the fastening adapter according to the invention is described as applied to a helmet. Besides a helmet, any other construction, and its wall, supported by the head can also be used. FIG. 1 shows a general-purpose helmet  10 , to which hearing protectors  11  and a visor  12  protecting the user&#39;s face are attached by means of a fastening adapter according to the invention. There are no pre-installed attachment holes or attachments in helmet  10 . On the other hand, it is possible to use the fastening adapter, even if there were previous attachments in the helmet. Naturally one fastening adapter is placed on either side of the helmet. From now on, the fastening adapter will be referred to more simply as the adapter. The principal components in the adapter are the body part  13 , the housing  14 , with an arm  15  corresponding to the product to be fastened in it, and a lock  17  to be installed inside the helmet  10 . A support arm  12 ′ for a visor  12  can also be attached using the adapter, whether or not hearing protectors  11  are installed. 
     FIGS. 2 a - 2   f  show the stages in the installation of the adapter. First, two holes  22  and  23  are drilled in the wall  19 , at a set distance from the lower edge (FIG. 2 a ). It is preferable to use a jig  24 , which is supplied with the adapter, when drilling. Next, body part  13  is placed against wall  19 , so that its protrusion  21 ′ lies in the lower hole  23  (FIG. 23 b ). Protrusion  21 ′ prevents body part  13  from rotating, when housing  14  is turned. At the same time, the prepared housing  14  is pushed through body part  13  against body part  13 . The second hole  22  drilled through wall  19  coincides with hole  13 ′, into which hole  22  axle pin  18 ′ of housing  14  is also pushed, to protrude from the opposite side of wall  19  (FIG. 2 c ). After this, lock  17  can be installed in groove  25  in axle pin  18 ′ and the slot  26  in lock  17  is set in protrusion  21 ′. Finally, lock  17  is turned against wall  19  and pressed into groove  25 , when the fastening is completed (FIGS. 2 d - 2   f ). Housing  14  also includes spring  16  and arm  15 . 
     Fastening member  18  of the adapter according to the invention is thus in two parts, the fastening devices of both of which are pins extending through the wall. Thus, the pins are also located a distance apart. In addition, the first fastening device comprises protrusion  21 ′ of body part  13 . Thus protrusion  21 ′ is preferably a pin, which extends through wall  19  to prevent body part  13  from rotating. The other fastening device comprises axle pin  18 ′ of housing  14 , which extends through both body part  13  and wall  19  (FIGS. 2 c - 2   f ). In addition, locking device  20  is fitted directly to axle pin  18 ′. 
     The adapter also includes a series of pairs of locking devices forming locks  17  for different wall thicknesses. In addition, there is a recess  27  in lock  17  for axle pin  18 ′. The lock suiting the case in question is selected from the pre-made locks, so that the thickness of its lock tongue/tip  28  corresponds to the thickness of the wall of the helmet or similar, together with the protrusion of axle pin  18 ′. Thus a suitable lock can always be found for different wall thicknesses and the fastening adapter can be installed in an arbitrary helmet. 
     FIG. 5 shows details of a comb  29  of locks of different thicknesses. Generally, the lock is made of the same material as the axle pin, which reduces wear in these parts. Usually the series comprises 2-6, more preferably 3-5 pairs of locking devices. The comb  29  of locks according to FIG. 5 has locks  17  of four different thicknesses, with a varying dimension S of the lock tongue  28 . In this embodiment, the range of variation at the base of recess  27  is 2.8-4.4 mm, divided into four alternative thicknesses. Generally the range of variation of thickness of the lock tongue is 2-5 mm on the bottom surface of the recess  27 , most preferably 2.5-4.5 mm. These alternatives are sufficient, as the combined flexibility of the body part, wall, axle pin, and lock allows for all the intermediate sizes. In addition, bottom surface  30  of recess  27  is angled, to compensate for the angle position of lock  17  in relation to axle pin  18 ′ in the locking position (see FIGS. 2 c - 2   e ). 
     FIGS. 3 and 4 show the parts of the adapter except for the lock. In FIGS. 3 and 4 the body part  13 , the housing  14 , the arm  15 , and the spring  16  are shown in detail. In housing  14  there is an axle pin  18 ′, which acts as a rotation axis. In body part  13  there is also a pin forming the aforementioned protrusion  21 ′, which prevents the body part  13  from rotating in relation to the side. At the upper end of arm  15  there are pins  31  and  31 ′, which correspond to the spaces  32  in housing  14 . U-shaped spring  16  presses against the upper end of arm  15 , which creates a force that presses hearing protectors  11  against the head of the user. 
     According to FIG. 4, there is a groove  25  at the end of axle pin  18 ′ to secure locking device  20 , and which runs round the entire circumference of axle pin  18 ′. The depth of groove  25  is parallel to the radius of axle pin  18 ′ and corresponds essentially to the dimensions of locking device  20 . In practice, locking device  20  is dimensioned so that when pressed it settles in groove  25  at essentially right angles to axle pin  18 ′. The shape of recess  27  of lock  17  can be seen particularly in FIG.  5 . Bevels  38  of recess  27  center lock  17  in relation to axle pin  18 ′ and, after a tight gap  39 , recess  27  again widens to permit axle pin  18 ′ to rotate freely. Though lock  17  can also be detached from axle pin  18 ′, it will not detach itself during use. 
     FIG. 5 further shows also the jig  24  belonging to the adapter, in which there are drill holes  33  and  33 ′. The drill holes  33  and  33 ′ in jig  24  are set at the distance between axle pin  18 ′ and protrusion  21 ′. The diameter of the first hole  33  in jig  24  corresponds to that of protrusion  21 ′ and the diameter of the second hole  33 ′ to that of axle pin  18 ′. Thus drill holes  33  and  33 ′ are the right sizes and at the right distance apart. In addition, there is a measure stick  34  at the end of jig  24  with hole  33 , for positioning jig  24  in relation to the lower edge of the side. This makes it easy to use jig  24  to position and drill holes  22  and  23 . 
     FIG. 2 b  also shows a slot  35  in axle pin  18 ′, by means of which the support arm  12 ′ of visor  12  is allowed to be pushed in when housing  14  is turned upside down (not show). After this, when the housing is once again turned downwards, the visor support arm is locked in place. Correspondingly, FIG. 3 also shows recess  36  in body part  13 , into which the visor support arm can be pushed. The support arm is locked into this recess with the aid of the housing, when the complete part of the axle rotates into the recess in its upper edge (not shown). The visor can then be rapidly fitted and removed, without tools. 
     The fastening adapter according to the invention is quite versatile, being suitable for all models of helmet. After the holes have been drilled, the fastening adapter can be fitted and, if desired, removed, without tools. It can also be fitted to headbands  10 ′ according to FIG.  6 . In the case of headbands, the installation of the fastening adapter corresponds to the manner of installation in a helmet, as described above. 
     One fastening adapter according to the invention is disclosed above. FIG. 7 shows a variation of the fastening adapter. In this, axle pin  18 ′ of housing  14  does not extend through wall  19 , instead it attached rotatably to body part  13 . In body part  13 , there is then another pin  37 , to which lock  17  used as a locking device  20  is fitted (not shown). The second pin  37  can also be set on another axis than axle pin  18 ′. The same reference numbers are used for components that are operationally similar. 
     Although the invention has been described by reference to a specific embodiment, it should be understood that numerous changes may be made within the spirit and scope of the inventive concepts described. Accordingly, it is intended that the invention not be limited to the described embodiment, but that it have the full scope defined by the language of the following claims.