Adjustable band for head-mounted display

1 . An apparatus for adjusting a tension of a head-mounted display (HMD), comprising:

a base plate including a stationary ratchet drum;

a rotating cap positioned over at least the stationary ratchet drum to define an internal space therebetween, the rotating cap including a plurality of walled structures projecting from an inner surface of the rotating cap and into the internal space; and

a ratchet positioned in the internal space and including a plurality of pawls connected to a hub of the ratchet and extending radially from the hub, wherein each pawl of the plurality of pawls includes a proximal end connected to the hub and a distal end including a head of the pawl, the head including:

a plurality of pawl teeth,

a first protrusion projecting transversely to the head, and

a second protrusion projecting transversely to the first protrusion, wherein the first protrusion and the second protrusion are received within a corresponding walled structure of the plurality of walled structures of the rotating cap and wherein the corresponding walled structure is configured to guide a pivoting movement of the pawl.

2 . The apparatus of claim 1 , further comprising a first strap and a second strap made of a rigid material.

3 . The apparatus of claim 2 , wherein the ratchet includes a pinion coupled to the ratchet at the hub, coupled to the first strap at a first end of the first strap, and coupled to the second strap at a second end of the second strap.

4 . The apparatus of claim 2 , wherein:

a first rotation of the rotating cap in a first rotational direction increases a tension in the first strap and the second strap; and

a second rotation of the rotating cap in a second rotational direction opposite the first rotational direction decreases the tension in the first strap and the second strap.

5 . The apparatus of claim 4 , wherein:

the first rotational direction includes a clockwise direction; and

the second rotational direction includes a counterclockwise direction.

6 . The apparatus of claim 1 , wherein:

each pawl of the plurality of pawls includes an arm; and

each arm is a same radial distance from a center of the ratchet.

7 . The apparatus of claim 1 , wherein the second protrusion contacts a wall of the corresponding walled structure.

8 . The apparatus of claim 1 , wherein the stationary ratchet drum includes a plurality of drum teeth on an inner circumferential surface of the stationary ratchet drum, and wherein the plurality of pawl teeth cooperate with the drum teeth.

9 . The apparatus of claim 8 , wherein the plurality of pawl teeth are configured to engage with the drum teeth and the second protrusion is configured to disengage with the corresponding walled structure when the rotating cap is in a tension holding configuration.

10 . The apparatus of claim 8 , wherein the plurality of pawl teeth are configured to disengage with the drum teeth and the second protrusion is configured to engage with the corresponding walled structure when the rotating cap is in a tension increasing configuration or a tension decreasing configuration.

11 . A ratchet, comprising:

a hub;

a pinion rigidly coupled to the hub; and

a plurality of pawls connected to the hub and extending radially from the hub, wherein each pawl of the plurality of pawls includes a proximal end connected to the hub and a distal end including a head of the pawl, the head including:

a plurality of pawl teeth,

a first protrusion projecting transversely to the head, and

a second protrusion projecting transversely to the first protrusion, wherein the first protrusion and the second protrusion are received within a corresponding walled structure of a plurality of walled structures projecting from an inner surface of a rotating cap and wherein the corresponding walled structure is configured to guide a pivoting movement of the pawl.

12 . The ratchet of claim 11 , wherein the second protrusion contacts a wall of the corresponding walled structure.

13 . The ratchet of claim 11 , wherein:

the rotating cap is positioned over a stationary ratchet drum to define an internal space therebetween;

the plurality of walled structures projects into the internal space; and

the ratchet is positioned in the internal space.

14 . The ratchet of claim 13 , wherein the stationary ratchet drum includes a plurality of drum teeth on an inner circumferential surface of the stationary ratchet drum, and wherein the plurality of pawl teeth cooperate with the drum teeth.

15 . The ratchet of claim 14 , wherein the plurality of pawl teeth are configured to engage with the drum teeth and the second protrusion is configured to disengage with the corresponding walled structure when the rotating cap is in a tension holding configuration.

16 . The ratchet of claim 14 , wherein the plurality of pawl teeth are configured to disengage with the drum teeth and the second protrusion is configured to engage with the corresponding walled structure when the rotating cap is in a tension increasing configuration or a tension decreasing configuration.

17 . The ratchet of claim 11 , wherein:

the pinion is coupled to a first strap at a first end of the first strap; and

the pinion is coupled to a second strap at a second end of the second strap.

18 . The ratchet of claim 17 , wherein:

a first rotation of the rotating cap in a first rotational direction increases a tension in the first strap and the second strap; and

a second rotation of the rotating cap in a second rotational direction opposite the first rotational direction decreases the tension in the first strap and the second strap.

19 . The ratchet of claim 18 , wherein:

the first rotational direction includes a clockwise direction; and

the second rotational direction includes a counterclockwise direction.

20 . The ratchet of claim 11 , wherein:

each pawl of the plurality of pawls includes an arm; and

each arm is a same radial distance from a center of the ratchet.