The present invention relates to an orienteering compass comprising a compass housing with a mcveable nor indicator and a base plate having a fixed course line. In order to enable a user of a compass -tDmcvc. in a given direction, the compass direction, conventional ^' orie teering compasses of the aforedescribed kind are equipped with a oveable compass housing. For the purpose of extracting a compass direction, the compass is placed on map or chart in a manner such that the course line coin¬ cides or extends parallel to the direction from a startin point to a target or goal. The compass housing is then ro tated so that lines marked on the compass housing coincid with or extend parallel to meridians on the map. In this respect it must be ensured that the north marking on the compass housing is directed towards north on the map. The compass is then removed from the map and rotated so that the north indicator coincides with the north narking on the compass housing. The correct compass direction is in- dicated by the course line on the base plate, when the compass is held in this position.

The aforedescribed method is relatively complicat ed and involves a number of error risks. Since the compas is normally read when completely separated from the map, an error in compass-house setting can take a long time tc discover. Thus, the original setting is not checked be¬ fore it becomes obvious that an error has been made, whic may be much too late. Further, it is difficult to teach the aforedescribed orienteering method so that a beginne can readily understand the coordination between compass and map. This is particularly true with respect to the transfer of a direction on a map to a corresponding com¬ pass direction. Simultaneous reading of the compass and map is made difficult by the fact that the compass and map are held in different hand, which constitutes a further error risk.

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The main object of the present invention is to provide an orienteering compass in which the aforemention¬ ed disadvantages are eliminated. To this end the compass according to the invention is so constructed that it must always be used in connection with a map, said compass be¬ ing characterized in that the compass housing is joined to the base plate in a non-rotatable fashion; and in that the base plate with the compass housing is so arranged that it can be pressed against and readily secured to a map with the course line in the desired direction.

According to the invention, the compass and map must be rotated as a unit in order to obtain the desired direction, and when aligning the map image in question is, at the same time, seen in a correctly orientated position. Thus , with each check of the direction there is also auto¬ matically obtained information concerning the map image or picture in question, or conversely each time the map image or picture is looked at it is possible, at the same time, by glancing at the north indicator of the compass, to check that the map is held correctly, i.e. orientated in the north-south direction, since it is only in this direction that the map image or picture agrees with reality.

In accordance with a preferred embodiment of the compass according to the invention, the compass housing is arranged with the centre of rotation of the north indicator located on the extended course line, which in the vicinity of the compass can have the form of a line drawn on the bottom of the compass housing or on the base plate. Further, that part of the course line which extends in front of the compass housing preferably coincides with a longitudinally extending edge of the base plate. This edge is suitably chamfered and provided wit a distance scale.

To facilitate pressing of the compass against a map, the compass is suitably provided with a thumb-grip comprising an adjustable stirrup-like structure intended for the thumb, said structure creferablv havinc the form

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of an elastic band preferably a rubber band, arranged on one side of the compass housing. For the purpose of in¬ creasing the friction betewen the thumb and the base plate and between the plate and the map, an area on both sides of the base plate is suitably provided with a fric¬ tion-increasing material. To facilitate use of the compass by persons with impaired sight, the compass may be provid¬ ed with a detachable magnifying glass covering the area immediately adjacent the edge of the base plate coinciding with the course line.

In accordance with a further variant cf the com¬ pass according to the invention, which variant is particu¬ larly suitable when the compass is used in search opera¬ tions and military operations, the north indicator has the form of a rotatable disc graduated in degrees, lines or the like.

The 'invention will now be described i more detail with reference to the accompanying drawings, in which

Figure 1 is a horizontal view of an orienteering compass according to the invention,

Figure 2 is a perspective view of the base plate, Figure 3 illustrates how a course is extracted on a map or chart,

Figure 4 illustrates hew the compass and chart are held while being used,

Figure 5 illustrates the base plate with a magni¬ fying glass mounted thereon, and

Figure 6 illustrates an alternative embodiment of the orienteering compass according to the invention. As will be seen from Figures 1 and 2 the orien¬ teering compass according to the invention comprises a base plate 1 having a recess 2 for receiving a compass housing 3. The compass housing 3 is ncn-rctatably mounted in the recess 2, ana may, alternatively, form, an integral part of the base plate 1. Mounted for free r tation in the compass housing is a magnetic north indicator, which in

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the illustrated embodiment has the form of a rotatable needle 4. The compass housing 3 is of known design, _and ±s suitable filled with a damping liquid and fully trans¬ parent. Extending in the bottom of the recess 2 is a course line 5, which coincides with a forward longitudinal edge 6 of the base plate 1. The edge 6 is chamfered to avoid the occurrence of disturbing reflections when read¬ ing the map, and is provided with a distance scale adapted to a suitable map scale. The reference 7 identifies a graduated straightedge, which can be used when measuring distances on maps having a different scale.

To enable the compass to be pressed and held against a map, the base plate is provided, on the side of the compass housing 3, with a thumb grip which includes an adjustable stirrup-like structure 8, and an area of friction-increasing material 9. An area of friction-in¬ creasing material corresponding to the area 9 is also suitably arranged on the opposite surface of the plate, to increase the friction against an underlying map. ^" The stirrup-like structure 8 suitably includes an elastic band, such as a rubber band, which passes through longi¬ tudinally extending slots 10, thereby enabling the stirrup to be readily adjusted. The slots 10 are parallel with the longitudinal direction of the thumb and are directed ob- liquely to the edge 6 of the plate 1. The reference 11 identifies a direction arrow.

The illustrated embodiment of the base plate 1 with an oblique rear edge and with the course line 5 coin¬ ciding with the edge 6 of the plate, and the illustrated position of the thumb grip 8 and the compass housing 3 en¬ able the compass to be readily and effectively pressed against and held to the map with one hand, and also en¬ ables the map to be orientated and read quickly and posi¬ tively. The portion 5 of the course line extending beneath the compass housing can be excluded to eliminate any con¬ fusion with the meridians on the mac

Figure 3 illustrates how the compass is used to¬ gether with the map for obtaining a correct direction bet¬ ween a starting point 12 and a goal 13. In this case, the compass is placed on the map so that the course line 5 coincides with or is parallel to a straight line betv.'een the starting point and said goal. In the example illustra¬ ted in Figure 3, the compass has been placed so that the atarting point 12 is located beneath the compass housing 3. However, the compass may. also be positioned, for example, so that the starting point 12 is located at a de¬ sired location on the distance scale on the edge 6 of the base plate 1. The compass is then fixed in the taken po¬ sition, by pressing the compass against the map with the thumb. In order to obtain a correct direction to the goal, the map need then only be aligned in the north- south direction, which must be done in all orienteering cases, since it is only in this position that the map pic¬ ture coincides with reality. This alignment of the map is effected by simply rotating compass and map as a unit un¬ til the north indicator 4 is parallel with the meridians 14 on the map. When this has been done, the correct di¬ rection to follow is straight forwards, i.e. in the direc¬ tion shown by the course line 5. Each time a map is studied, the map is thus orien¬ tated with the aid of the north indicator, wherat the correct direction is automatically obtained at the same time. Since the compass and map are held fixed relative to one another with only one hand, there is no risk of er- rors of the kind which readily occur when using conventio¬ nal compasses, where the compass is held in one hand and the map in the other. This latter method makes it diffi¬ cult to precisely orientate the map when reading the same. Further, in the case of a conventional compass an informa- tion of the map image in question is not automatically obtained when checking t e compass course, as opposed to

the case when checking the compass course with the com¬ pass according to the invention, in which the map is read adjacent the course line. As the person using the compass moves along the line extending between the starting point 12 and the goal 13, the compass, if so desired, can also be moved along said line, so that the map can be constant¬ ly read together with the distance scale. This is an ad¬ vantage since in orienteering, the distance is continuous¬ ly checked by counting the number of steps taken. Figure 4 illustrates how the map and compass are held firmly while checking both direction and the map image or picture. This can also be done while running, which is not possible when using conventional compasses, since compass and map are held in different hands. Thus, the most important advantages afforded by an orienteering compass according to the invention are that the compass affords rapid, positive and simple orien¬ teering, which can also be readily learned and taught. As before mentioned, it is extremely simple, among other things, to extract the direction in which it is desired to move, since it is only necessary to place the compass in the desired directicn on the map and then to align the map with the compass fixed thereon, whereafter the cor¬ rect direction is straight forwards in the direction shown by the course arrow, which directicn will thus coincide with the direction on the map. There is hardly any chance of an error being made. Changes in direction can be readi¬ ly made, since it is only necessary to totate the compass on the map and then to reorientate the map, the course arrow then pointing in the new, correct direction. As also mentioned in the aforegoing, the map can be read po¬ sitively and quickly, since the map is always read in a correctly orientated position and adjacent the course line. The base plate 1 is, in this respect, suitably so formed that the thumb extends to the position at which the map is read.

When the map is read over a relatively small area adajcent the chamfered edge 6, the compass may be readily provided with a magnifying glass 15, as illustrated sche¬ matically in Figure 5. In this embodiment, the magnifying glass 15 is provided with an annular holder 16 which fits around the compass housing 3. The holder 16 is suitably so formed that the magnifying glass 15 can only be fitted over and removed from the compass housing 3 in a given position of rotation, which differs from the position illustrated in the Figure, this latter position being used when reading the map.

Figure 6 illustrates an alternative embodiment of a compass according to the invention which is particular¬ ly suited for use by search parties and in military opera- tions, where a number of people must move in a given di¬ rection. In the compass according to the Figure 6 embodi¬ ment, the north indicator is provided with a rotatable ^' disc 17 graduated in degrees or lines. In this case, the leader need only extract a course on a map and inform the persons taking part in the search or the military opera¬ tion as to the number of degrees or lines which corre¬ spond to the desired direction. The members of the search party or military operation need then only turn so that the course line cf the compass corresponds to the number on the disc 17, and move in the correct direction, which is straight forwards, i.e. in the directicn cf the exten¬ sion of the course line. A corresponding design may also be used for navigation on board a ship. In this respect, the base plate is given a greater length and is suitably provided with suction cups on the bottom thereof, to en¬ able the compass to be fixed to a map-reading table. The aforementioned thumb grip is not required in this case.

The compass according to the invention may also be varied in other respects within the scope of the claims, among other things ^* with respect to the geometric

shape of the base plate and the holder means thereon, and also with respect to the positioning and form of the course line. A common feature of all embodiments is that they include a base plate and a compass housing non-ro- tatably connected thereto, whereat the correct direction is determined while holding the compass in direct contact with a map, chart or the like. Thus, the setting of the north indicator is read directly against the meridians of the map and not against markings on the compass housing.