Tilt angle adjustment mechanism capable of both discrete and fine adjustment

A tilt angle adjustment mechanism capable of both discrete and fine adjustment includes a bracket, a housing tiltably connected to the bracket and a wheel disposed between the bracket and the housing and rotatably connected to the bracket. A spiral guiding member is provided on the wheel and engages with a curved row of evenly spaced detents at the housing to fix the housing to the wheel at plural predetermined tilt angles defined by the detents to achieve discrete tilt angle adjustment of the housing, and rotation of the wheel drives the spiral guiding member to slide through the curved row of detents and causes the tilt angle of the housing to continuously change with the rotation.

BACKGROUND OF THE INVENTION

The present invention relates to a tilt angle adjustment mechanism capable of both discrete and fine adjustment of the tilt angle of a device housing such as a headlamp housing relative to a bracket.

Personal headlamps available in the prior art are commonly provided with tilt angle adjustment brackets which utilize certain snap mechanisms for adjusting the light of the headlamps to be directed to different angles. However, such mechanisms are capable of directing the light to a predetermined number of discrete angles only. It is impossible to further fine tune the tilt angle between successive discrete angles.

BRIEF SUMMARY OF THE INVENTION

In view of the aforesaid disadvantages now present in the prior art, an object of the present invention is to provide a tilt angle adjustment mechanism capable of both discrete and fine adjustment of the tilt angle of a device housing such as a headlamp housing relative to a bracket.

To attain this, the present invention comprises a bracket, a housing and a wheel. The housing is tiltably connected to the bracket so as to tilt around a tilt axis relative to the bracket in a predetermined range of tilt angles. The wheel is disposed between the bracket and the housing for adjusting the tilt angle of the housing; the wheel is rotatably connected to the bracket so as to rotate around a rotation axis which is perpendicular to a planar surface of the wheel and perpendicular to the tilt axis. A spiral guiding member is disposed on the planar surface of the wheel which faces towards the housing. A curved row of evenly spaced detents is provided at the housing for engaging with the spiral guiding member, which is pressed towards the curved row of detents by a biasing means, to fix the housing to the wheel at plural predetermined tilt angles defined by the detents to achieve discrete tilt angle adjustment of the housing, and rotation of the wheel drives the spiral guiding member to slide through the curved row of detents and causes the tilt angle of the housing to continuously change with the rotation.

In some embodiments, the spiral guiding member is in form of an approximately one-turn spiral with a first end portion adjacent to an inner side of a second end portion to allow two successive detents to respectively engage with the first end portion and the second end portion.

In some embodiments, the spiral guiding member is in form of a ridge protruding from the wheel, and the curved row of detents comprises a plurality of detent grooves.

In some embodiments, the detent grooves are defined by gaps between arc shaped ridges protruding from the housing.

In some embodiments, the biasing means is in form of a spring arm disposed on the bracket which presses on the wheel at a position corresponding to where the spiral guiding member and the curved row of detents are engaged.

In some embodiments, the curved row of evenly spaced detents is provided in middle of a bottom edge of a side of the housing which faces towards the wheel.

In some embodiments, the wheel is knurled at its periphery.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is further described in detail with the following embodiment.

As illustrated inFIGS.1to7, an embodiment of the present invention is a tilt angle adjustment mechanism for a personal headlamp wearable on a user's head which comprises a bracket1, a housing2and a wheel3. In other embodiments, the tilt angle adjustment mechanism could also be applied to other devices such as video cameras and so forth.

The bracket1has a pair of slots11at two sides thereof for a head strap12to pass through. The housing2receives the operative elements of the headlamp such as the battery, light emitting member and so forth. As the operative elements of the headlamp are commonly known in the art, they are not detailed herein. The housing2is tiltably connected to the bracket1by rotational engagement of two annular protrusions21at two sides of the housing2with two corresponding annular recesses13at two sides of the bracket1, so as to tilt around a tilt axis22relative to the bracket1in a predetermined range of tilt angles23.

The wheel3is disposed between the bracket1and the housing2for adjusting the tilt angle23of the housing2. The wheel3is rotatably connected to the bracket1so as to rotate around a rotation axis31. In this embodiment, the rotation axis31is in form of a bolt shaft which is perpendicular to a planar surface32of the wheel3and perpendicular to the tilt axis22. The wheel3is knurled at its periphery to facilitate the user to rotate the wheel3.

A spiral guiding member4is disposed on the planar surface32of the wheel3which faces towards the housing2. In this embodiment, the spiral guiding member4is in form of an approximately one-turn spiral ridge protruding from the wheel3with a first end portion41adjacent to an inner end421of a second end portion42. The distance from the spiral guiding member4to the center of the wheel3increases in a counter-clockwise direction from the first end portion41to the second end portion42.

A curved row of evenly spaced detents5is provided in middle of a bottom edge of a rear side24of the housing2which faces towards the wheel3. In this embodiment, the curved row of detents5comprises six detent grooves5a,5b,5c,5d,5e,5fthat are in identical arc shape and evenly spaced. The six detent grooves5b,5c,5d,5e,5fare defined by the gaps between arc shaped ridges protruding from the housing2. The six detent grooves5a,5b,5c,5d,5e,5fare each configured to engage with the spiral guiding member4, and two successive detent grooves may respectively engage with the first end portion41and the second end portion42of the spiral guiding member4.

The spiral guiding member4is pressed towards the curved row of detents by a biasing means6. The biasing means6in this embodiment is in form of a spring arm disposed on the bracket1which presses the wheel3at a position corresponding to where the spiral guiding member4and the curved row of detents5are engaged. Engagement of the curved row of detents5with the spiral guiding member4fixes the housing2to the wheel3at plural predetermined tilt angles23defined by the detent grooves5a-5fto achieve discrete tilt angle adjustment of the housing2.

The tilting operation of the housing2relative to the bracket1is explained in detail as follows. Initially, the housing2is at an upright position where the rear side24of the housing2is substantially parallel to the wheel3, and the tilt angle23is 0 degree. At the upright position, the topmost detent groove5aengages with the second end portion42of the spiral guiding member4. When the user tilts the housing2downwards (i.e. increases the tilt angle23) without rotating the wheel3, the curved row of detents5slides upwards against the spiral guiding member4; when the housing2is tilted to a desired angle, the user stops tilting and the spiral guiding member4then engages with the nearest detent groove(s). This completes the discrete tilt angle adjustment of the housing2. Similarly, when the user wishes to tilt the housing2upwards, the curved row of detents5slides downwards against the spiral guiding member4and engages with the nearest detent groove(s) when the user stops tilting.

If the user wishes to fine tune the tilt angle23of the housing2, the user rotates the wheel3. For example, when the housing2is at the upright position and the user wishes to increase the tilt angle23(i.e. to tilt the housing2further downwards), the user rotates the wheel3in a counter-clockwise direction to drive the spiral guiding member4to slide through the detent groove5a, and the housing2is thereby tilted downwards away from the wheel3with the tilt angle23continuously changes with the rotation. When the desired tilt angle23is reached, the user simply stops rotating the wheel3, and the biasing action of the biasing means6keeps the housing2at the desired tilt angle23. After one complete revolution of the wheel3, the topmost detent groove5aengages with the first end portion41of the spiral guiding member4while the second topmost detent groove5bengages with the second end portion42of the spiral guiding member4; in other words, one complete revolution of the wheel3fine tune the tilting angle23of the housing1by the angle between successive detent grooves. If the wheel3is further rotated counter- clockwise, the spiral guiding member4then slides through the second topmost detent groove5band after another one complete revolution of the wheel3, the second topmost detent groove5bengages with the first end portion41and the third topmost detent groove5cengages with the second end portion42of the spiral guiding member4. If the user at this point wishes to decrease the tilt angle23(i.e. to tilt the housing2further upwards), the user rotates the wheel3in a clockwise direction, the spiral guiding member4slides through the second topmost detent groove5band after one complete revolution of the wheel3, the second topmost detent groove5bengages with the second end portion42of the spiral guiding member4and the topmost detent groove5aengages with the first end portion41of the spiral guiding member4.

The above embodiment is one of the embodiments of the present invention. The present invention is capable of other embodiments and is not limited by the above embodiment. Any other variation, decoration, substitution, combination or simplification, whether in substance or in principle, not deviated from the spirit of the present invention, is replacement or substitution of equivalent effect and falls within the scope of protection of the present invention.