Patent Description:
A known helmet includes an attachment-detachment mechanism that allows a shield to be attached and detached by performing an operation from outside the helmet. The attachment-detachment mechanism includes an attachment-detachment member that is moved between a shield holding position and a shield removable position. The attachment-detachment member is biased to the shield holding position by a biasing member and moved to the shield removable position when an operation force that counters the biasing force is applied from outside the helmet. <CIT> discloses an example. <CIT> discloses a shield lock mechanism according to the preamble of claim <NUM>.

In the attachment-detachment mechanism, when a strong impact is applied to the helmet, inertial force that counters the biasing force acts on the attachment-detachment member may move the attachment-detachment member from the shield holding position to the shield removable position in an unexpected manner.

An objective of the present disclosure is to provide a shield lock mechanism and a helmet that avoids a situation in which a holding member that holds the shield is moved by an impact.

A shield lock mechanism in accordance with the present disclosure is for attachment to a shell. The shield lock mechanism includes a holding member, a biasing member, and a restriction member. The holding member is configured to be moved by an external operation between a holding position at which a shield is held and an attachment-detachment position at which the shield can be attached and detached. The biasing member is configured to constantly bias the holding member toward the holding position. The restriction member is configured to be moved by an external operation between a restricting position at which movement of the holding member arranged at the holding position is restricted and a canceling position at which the restriction is canceled.

A helmet in accordance with the present disclosure includes a shell, a shield, and the above-described shield lock mechanism.

An embodiment of a shield lock mechanism will now be described with reference to <FIG>. In <FIG>, the front, rear, left, right, up, and down directions with respect to a helmet and the shield lock mechanism correspond to the directions as viewed by a person wearing the helmet.

As shown in <FIG>, a helmet <NUM> includes a shell <NUM>, a shield <NUM>, and a shield lock mechanism <NUM>. A wearer of the helmet <NUM> wears the shell <NUM> on the head. The shell <NUM> has a window opening <NUM>. The window opening <NUM> ensures the field of view of the helmet wearer. The shield <NUM> is light-transmissive. When the window opening <NUM> is closed with the shield <NUM>, the shield <NUM> protects the head of the helmet wearer while maintaining the field of view of the helmet wearer. The shield <NUM> is attached to a left side surface of the shell <NUM> by the shield lock mechanism <NUM> such that the shield lock mechanism <NUM> is sandwiched between the shield <NUM> and the shell <NUM>.

As shown in <FIG>, the shield lock mechanism <NUM> includes a base plate <NUM>, a holding member <NUM>, a restriction member <NUM>, a first coil spring <NUM>, and a second coil spring <NUM>. The second coil spring <NUM> is an example of a biasing member.

The base plate <NUM> includes two bases. Each base is a plate that is curved in correspondence with the left side surface of the shell <NUM>. The two bases include a fixed base <NUM> and a movable base <NUM>. The fixed base <NUM> is fixed on the left side surface of the shell <NUM>. The movable base <NUM> is arranged to cover a left portion of the fixed base <NUM>. The movable base <NUM> is connected to the fixed base <NUM> in a manner movable in forward and rearward directions.

The fixed base <NUM> and the movable base <NUM> sandwich part of the holding member <NUM> (refer to <FIG>), part of the restriction member <NUM> (refer to <FIG>), and part of the second coil spring <NUM> (refer to <FIG>). The first coil spring <NUM> extends in the front-rear direction and is connected between the fixed base <NUM> and the movable base <NUM>. The first coil spring <NUM> is in contact with the fixed base <NUM> and the movable base <NUM> and constantly biases the movable base <NUM> toward the rear of the helmet wearer.

The base plate <NUM> includes a first engagement hole <NUM>, a second engagement hole <NUM>, and an opening degree determination portion <NUM>.

The first engagement hole <NUM> includes a first attachment-detachment hole 31A and a first guide hole 31B. The first attachment-detachment hole 31A is a substantially rectangular small hole extending through a portion of the movable base <NUM> peripheral to the upper end of the movable base <NUM>. The first guide hole 31B is an elongated hole extending through a portion of the movable base <NUM> peripheral to the upper end of the movable base <NUM>. The first guide hole 31B extends rearward from the first attachment-detachment hole 31A in an arcuate manner.

The shield <NUM> includes a first engagement tab 3A projecting toward the fixed base <NUM>. The first engagement tab 3A has a claw-shaped distal end that is bent downward. The distal end of the first engagement tab 3A is sized to enter the space between the fixed base <NUM> and the movable base <NUM> through the first attachment-detachment hole 31A. Further, the distal end of the first engagement tab 3A is sized to be removable from between the fixed base <NUM> and the movable base <NUM> through the first attachment-detachment hole 31A. The first engagement tab 3A has a thickness such that the first engagement tab 3A is slidable in the first guide hole 31B along the first guide hole 31B. The thickness of the first engagement tab 3A corresponds to the amount of the first engagement tab 3A extending from the shield <NUM> toward the fixed base <NUM> such that the first engagement tab 3A is slidable in the first guide hole 31B. The first guide hole 31B guides the movement of the first engagement tab 3A in the direction in which the first guide hole 31B extends. The first engagement tab 3A is guided by the first guide hole 31B so that the shield <NUM> is stably opened and closed.

The second engagement hole <NUM> includes a second attachment-detachment hole 32A and a second guide hole 32B. The second attachment-detachment hole 32A (refer to <FIG>) is a substantially rectangular hole extending through a portion of the movable base <NUM> peripheral to the upper end of the movable base <NUM> in front of the first attachment-detachment hole 31A. The second attachment-detachment hole 32A is larger than the first attachment-detachment hole 31A. The second guide hole 32B is an elongated hole extending through the movable base <NUM>. The second guide hole 32B extends in an arcuate manner from the second attachment-detachment hole 32A toward the rear lower end of the movable base <NUM>.

The shield <NUM> includes a second engagement tab 3B projecting toward the fixed base <NUM>. The second engagement tab 3B has a claw-shaped distal end that is bent upward and rearward. The distal end of the second engagement tab 3B is sized to enter the space between the fixed base <NUM> and the movable base <NUM> through the second attachment-detachment hole 32A. Further, the distal end of the second engagement tab 3B is sized to be removable from between the fixed base <NUM> and the movable base <NUM> through the second attachment-detachment hole 32A. The second engagement tab 3B has a thickness such that the second engagement tab 3B is slidable in the second guide hole 32B along the second guide hole 32B. The thickness of the second engagement tab 3B corresponds to the amount of the second engagement tab 3B extending from the shield <NUM> toward the fixed base <NUM> such that the second engagement tab 3B is slidable in the second guide hole 32B. The second guide hole 32B guides the movement of the second engagement tab 3B in the direction in which the second guide hole 32B extends. The second engagement tab 3B is guided by the second guide hole 32B so that the shield <NUM> is stably opened and closed.

The opening degree determination portion <NUM> is located at a portion of the fixed base <NUM> that is not covered by the movable base <NUM>. The opening degree determination portion <NUM> includes a multi-serrated engagement portion 21A and an attachment-detachment stepped portion 21B arranged on the fixed base <NUM>. The multi-serrated engagement portion 21A extends in an arcuate manner from the front upper end of the fixed base <NUM> toward the rear lower end of the fixed base <NUM>. The multi-serrated engagement portion 21A includes ridges that project toward the front and valleys that are recessed toward the rear, and the ridges and the valleys are alternately arranged along the multi-serrated engagement portion 21A. The attachment-detachment stepped portion 21B is an upwardly extending recess that is continuous with the upper end of the multi-serrated engagement portion 21A.

The shield <NUM> includes an opening degree adjustment projection 3C projecting toward the fixed base <NUM>. The opening degree adjustment projection 3C is sized to move into the valleys of the multi-serrated engagement portion 21A and the recess of the attachment-detachment stepped portion 21B. Further, the opening degree adjustment projection 3C is flexible so that the opening degree adjustment projection 3C moves over the ridges of the multi-serrated engagement portion 21A one at a time when opening or closing the shield <NUM>. When the first engagement tab 3A is moved in the first guide hole 31B and the second engagement tab 3B is moved in the second guide hole 32B, the opening degree adjustment projection 3C enters one of the valleys of the multi-serrated engagement portion 21A and fixes the opening degree of the shield <NUM>. Further, as shown in <FIG>, when the opening degree adjustment projection 3C enters the attachment-detachment stepped portion 21B of the fixed base <NUM>, the shield <NUM> is in a fully open position.

As shown in <FIG>, when the shield <NUM> is in a fully closed position, the first engagement tab 3A is in the first guide hole 31B and the second engagement tab 3B is in the second guide hole 32B. This holds the shield <NUM> with the base plate <NUM>. Also, the opening degree adjustment projection 3C is in the lowest valley of the multi-serrated engagement portion 21A. This fixes the shield <NUM> in the fully closed position. When the shield <NUM> is operated and opened from this state, the first engagement tab 3A is moved along the first guide hole 31B, the second engagement tab 3B is moved along the second guide hole 32B, and the opening degree adjustment projection 3C is moved over the ridges of the multi-serrated engagement portion 21A one at a time. This intermittently fixes the opening degree of the shield <NUM>.

As shown in <FIG>, when the shield <NUM> reaches the fully open position, the first engagement tab 3A is in the first attachment-detachment hole 31A and the second engagement tab 3B is in the second attachment-detachment hole 32A. Further, the opening degree adjustment projection 3C is in the attachment-detachment stepped portion 21B. This allows the shield <NUM> to be removed by performing an external operation on the holding member <NUM> and the restriction member <NUM>.

As shown in <FIG>, the fixed base <NUM> includes a first attachment portion <NUM> and a second attachment portion <NUM>. Each of the first attachment portion <NUM> and the second attachment portion <NUM> is a projection projecting toward the movable base <NUM>. The first attachment portion <NUM> includes a screw hole 22A, and the second attachment portion <NUM> includes a screw hole 23A. Screws are inserted through the screw holes 22A and 23A and fastened to the shell <NUM> to fix the fixed base <NUM> to the shell <NUM>. The first attachment portion <NUM> includes a spring seat 22W projecting toward the rear (refer to <FIG>).

The movable base <NUM> includes an attachment-detachment operation hole <NUM>, a lock lever hole <NUM>, a shaft support hole <NUM>, and a movable hole <NUM>. Further, the movable base <NUM> includes a spring seat 33W that is formed in front of the attachment-detachment operation hole <NUM> and a spring seat 36W that is formed at the rear of the movable hole <NUM>. The first attachment portion <NUM> is inserted through the movable hole <NUM>. The first coil spring <NUM> is supported by the spring seat 22W of the fixed base <NUM>, which is located at the rear of the first attachment portion <NUM>, and the spring seat 36W of the movable base <NUM>, which is located at the rear of the movable hole <NUM>.

As shown in <FIG>, the first coil spring <NUM> constantly biases the movable base <NUM> toward the rear relative to the fixed base <NUM>. For example, when the movable base <NUM> receives an operation force that counters the biasing force of the first coil spring <NUM>, the movable base <NUM> is moved toward the front together with the shield <NUM>.

For example, when the shield <NUM> is moved between the fully closed position and the fully open position, the opening degree adjustment projection 3C of the shield <NUM> alternately contacts the ridges and the valleys of the multi-serrated engagement portion 21A. When the opening degree adjustment projection 3C is moved from one valley onto an adjacent ridge, the movable base <NUM> receives an external force that counters the biasing force of the first coil spring <NUM>. This moves the movable base <NUM> forward. Specifically, the helmet wearer applies an operation force that counters the biasing force of the first coil spring <NUM> to the shield <NUM> and moves the movable base <NUM>. This moves the opening degree adjustment projection 3C from one valley onto an adjacent ridge and moves the shield <NUM>. Further, when the helmet wearer applies no operation force countering the biasing force of the first coil spring <NUM> to the shield <NUM>, the opening degree adjustment projection 3C stays in contact with the valley and fixes the opening degree of the shield <NUM>.

As shown in <FIG>, the holding member <NUM> includes a shield holding tab <NUM>, an attachment-detachment lever <NUM>, and a connecting plate <NUM>. The attachment-detachment lever <NUM> is an example of an operating portion. The shield holding tab <NUM> is defined by an upper end of the holding member <NUM> and is plate-shaped. The shield holding tab <NUM> is sized to be pivotal in forward and rearward directions in the second attachment-detachment hole 32A. The attachment-detachment lever <NUM> is looped and defined by a lower end of the holding member <NUM>. The attachment-detachment lever <NUM> is sized to be pivotal in forward and rearward directions in the attachment-detachment operation hole <NUM>, which extends through the movable base <NUM>. The lower end of the attachment-detachment operation hole <NUM> is defined by a pivot guide surface 33E that is curved and extends in the front-rear direction. The pivot guide surface 33E contacts the lower end wall of the attachment-detachment lever <NUM> to guide pivoting of the attachment-detachment lever <NUM>.

The connecting plate <NUM> is a plate-shaped portion that connects the shield holding tab <NUM> and the attachment-detachment lever <NUM> in the up-down direction. The connecting plate <NUM> is accommodated between the fixed base <NUM> and the movable base <NUM>. A groove is formed in the surface of the movable base <NUM> facing the fixed base <NUM>, and the groove extends in the up-down direction to accommodate the connecting plate <NUM>. The connecting plate <NUM> is guided by the side surfaces of the groove in the movable base <NUM> to allow pivoting of the shield holding tab <NUM> and the holding member <NUM>.

When the attachment-detachment lever <NUM> is arranged at the rear end of its movable range, the shield holding tab <NUM> is arranged at the front end of its movable range. Accordingly, when an external operation force is not acting on the holding member <NUM>, the attachment-detachment lever <NUM> is arranged at the rear end and the shield holding tab <NUM> is arranged at the front end. Thus, the holding member <NUM> is in a holding position.

In contrast, when an operation force from the front toward the rear is acting on the holding member <NUM>, the attachment-detachment lever <NUM> is arranged at the front end of its movable range and the shield holding tab <NUM> is arranged at the rear end of its movable range. Thus, the holding member <NUM> is in an attachment-detachment position. In this manner, when an external operational force is acting on the holding member <NUM>, the holding member <NUM> is in the attachment-detachment position. The direction in which the holding member <NUM> is moved from the holding position corresponds to the direction in which the shield holding tab <NUM> is moved, and the direction includes a main component in the front-rear direction.

The movable base <NUM> includes a plate-shaped shield sandwiching tab 32C that extends from the front end of the second attachment-detachment hole 32A toward the inner side of the second attachment-detachment hole 32A. If the shield holding tab <NUM> is arranged at the front end of its movable range when the second engagement tab 3B of the shield <NUM> is located inside the second attachment-detachment hole 32A, the second engagement tab 3B of the shield <NUM> will be sandwiched between the shield sandwiching tab 32C and the shield holding tab <NUM> so that the second engagement tab 3B of the shield <NUM> cannot be removed from the second attachment-detachment hole 32A. In this case, the shield <NUM> is continuously held by the shield lock mechanism <NUM>. Further, if the shield holding tab <NUM> is arranged at the rear end of its movable range when the second engagement tab 3B of the shield <NUM> is located inside the second attachment-detachment hole 32A, the second engagement tab 3B of the shield <NUM> can be removed from the second attachment-detachment hole 32A.

The second coil spring <NUM> is supported by the spring seat 33W of the movable base <NUM>, which projects toward the attachment-detachment operation hole <NUM>, and a spring seat 42W that is arranged on the attachment-detachment lever <NUM> and projects toward the front. The second coil spring <NUM> constantly biases the attachment-detachment lever <NUM> toward the rear end of the movable range of the attachment-detachment lever <NUM>. When the attachment-detachment lever <NUM> receives an operation force that counters the biasing force of the second coil spring <NUM>, the attachment-detachment lever <NUM> is moved toward the front end of its movable range and the shield holding tab <NUM> is moved toward the rear end of its movable range.

The restriction member <NUM> includes a lock lever <NUM>, a restriction projection <NUM>, and a shaft portion <NUM>. The shaft portion <NUM> is an example of a shaft support portion. The shaft portion <NUM> has the form of a disc, and the lock lever <NUM> and the restriction projection <NUM> are connected to the circumferential surface of the shaft portion <NUM>. The shaft portion <NUM> is rotatably supported by the movable base <NUM> in the shaft support hole <NUM>. The shaft portion <NUM> is rotated by an external operation that rotates the lock lever <NUM>, and the shaft portion <NUM> rotates the restriction projection <NUM> in the same direction as the rotational direction of the lock lever <NUM>.

The lock lever <NUM> is a lever extending from the shaft portion <NUM> toward the front. The lock lever <NUM> is sized to be pivotal in the lock lever hole <NUM> of the movable base <NUM>. The lock lever <NUM> is pivoted between a canceling operation position and a restricting operation position. In the canceling operation position, the distal end of the lock lever <NUM> is at the uppermost position of its movable range. In the restricting operation position, the distal end of the lock lever <NUM> is at the lowermost position of its movable range.

The restriction projection <NUM> is a projection extending from the shaft portion <NUM> toward the rear. The restriction projection <NUM> is sized to be pivotal between the fixed base <NUM> and the movable base <NUM>. The restriction projection <NUM> is pivoted between a restricting actuation position and a canceling actuation position. In the restricting actuation position, the distal end of the restriction projection <NUM> contacts the attachment-detachment lever <NUM> arranged at the rear end of it movable range. In the canceling actuation position, the distal end of the restriction projection <NUM> does not contact the attachment-detachment lever <NUM> arranged at the rear end of its movable range.

When the lock lever <NUM> is in the restricting operation position, the restriction projection <NUM> is in the restricting actuation position and the restriction member <NUM> is in the restricting position. The restriction member <NUM> in the restricting position fixes the attachment-detachment lever <NUM> at the rear end of its movable range to restrict movement of the holding member <NUM> from the holding position.

In contrast, when the lock lever <NUM> is in the canceling operation position, the restriction projection <NUM> is in the canceling actuation position and the restriction member <NUM> is in the canceling position. The restriction member <NUM> in the canceling position permits movement of the attachment-detachment lever <NUM> from the rear end of its movable range. This allows the holding member <NUM> to be moved by an external operation from the holding position to the attachment-detachment position. The direction in which the restriction member <NUM> is moved from the restricting position corresponds to the direction in which the restriction projection <NUM> is moved and the rotational direction about the shaft portion <NUM>. The direction includes a main component in the up-down direction.

As shown in <FIG>, an operation force is applied to the lock lever <NUM> to move the restriction member <NUM> between the restricting operation position (solid line) and the canceling operation position (double-dashed line). When the restriction member <NUM> is in the restricting actuation position, the restriction projection <NUM> contacts the attachment-detachment lever <NUM> and restricts movement of the holding member <NUM> from the holding position to the attachment-detachment position.

In this case, even when an impact is applied to the helmet <NUM>, the holding member <NUM> will resist and not be moved by the inertial force acting on the holding member <NUM>. Further, the direction in which the holding member <NUM> is moved from the holding position differs from the direction in which the restriction member <NUM> is moved from the restricting position. Specifically, the direction in which the holding member <NUM> is moved from the holding position to the attachment-detachment position differs from the direction in which the restriction member <NUM> is moved from the restricting position to the canceling position. This will limit the inertial force that acts on and moves both of the holding member <NUM> and the restriction member <NUM>. Therefore, even when an external impact is applied to the helmet <NUM>, the shield <NUM> will be continuously held by the shield lock mechanism <NUM>.

When the restriction member <NUM> is in the canceling actuation position, the restriction projection <NUM> is separated from the attachment-detachment lever <NUM> to permit the movement of the holding member <NUM> from the holding position to the attachment-detachment position.

As shown in <FIG>, if the restriction member <NUM> is arranged in the canceling actuation position when the shield <NUM> is in the fully open position, the first engagement tab 3A will be arranged in the first attachment-detachment hole 31A and the second engagement tab 3B will be arranged in the second attachment-detachment hole 32A. In this case, when the attachment-detachment lever <NUM> receives an operation force that counters the biasing force of the second coil spring <NUM>, the holding member <NUM> is moved from the holding position to the attachment-detachment position. This allows the shield <NUM> to be removed from the shield lock mechanism <NUM>.

When attaching the shield <NUM> to the shell <NUM>, first, the restriction member <NUM> is arranged in the canceling actuation position. Then, an operation force that counters the biasing force of the second coil spring <NUM> is applied to the attachment-detachment lever <NUM> to move the holding member <NUM> from the holding position to the attachment-detachment position. In this state, the first engagement tab 3A is inserted through the first attachment-detachment hole 31A, the second engagement tab 3B is inserted through the second attachment-detachment hole 32A, and then the opening degree adjustment projection 3C is arranged in the attachment-detachment stepped portion 21B. This attaches the shield <NUM> to the shield lock mechanism <NUM>.

The above embodiment has the following advantages.

The above embodiment may be modified as described below.

Advantages (<NUM>) to (<NUM>) will be obtained as long as the first coil spring <NUM> and the second coil spring <NUM> are configured to apply biasing force to the movable base <NUM> or the holding member <NUM>, respectively. For example, the first coil spring <NUM> and the second coil spring <NUM> may each be a biasing member such as a leaf spring or a disc spring.

The shield lock mechanism <NUM> is not limited to a structure in which the second coil spring <NUM> and the restriction member <NUM> both contact the attachment-detachment lever <NUM>. The shield lock mechanism <NUM> may be configured so that the second coil spring <NUM> and the restriction member <NUM> apply an acting force to different portions of the holding member <NUM>. For example, advantages (<NUM>) to (<NUM>) will be obtained even when the second coil spring <NUM> contacts the attachment-detachment lever <NUM> and the restriction member <NUM> contacts the shield holding tab <NUM>.

The holding member <NUM> only has to be movable between the holding position and the attachment-detachment position when an external operation force is applied. For example, the holding member <NUM> may be supported by a rotational shaft and rotated by an external operation force. Alternatively, the holding member <NUM> may be a push-down switch, an on-off switch, or a screw switch. The above-mentioned structures will also have advantages (<NUM>) to (<NUM>).

Claim 1:
A shield lock mechanism (<NUM>) for attachment to a shell (<NUM>), the shield lock mechanism (<NUM>) comprising:
a holding member (<NUM>) configured to be moved by an external operation between a holding position at which a shield (<NUM>) is held and an attachment-detachment position at which the shield (<NUM>) can be attached and detached;
a biasing member (<NUM>) configured to constantly bias the holding member (<NUM>) toward the holding position; and being characterized by
a restriction member (<NUM>) configured to be moved by an external operation between a restricting position at which movement of the holding member (<NUM>) arranged at the holding position to the attachment-detachment position is restricted and a canceling position at which the restriction is canceled.