Marking device

A marking device is disclosed which efficiently reduces damage affecting the gimbal mechanism even when such is used under sever conditions and is dropped from a high position. A marking device has a support mounted inside a housing, a light source unit holder swingably suspended by the support through a gimbal mechanism, and a light source unit mounted on the light source unit holder so as to diffuse a light flux only in a single direction to radiate a line of light. The support is coupled with said housing 1 through dampers with upper portion and lower portion formed of an impact absorber, and when outside impact is applied, the damper absorbs impact energy to prevent the impact force from being transmitting to the support.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a marking device configured for irradiating a vertical or horizontal line laser to a surface of the subject to be irradiated by diffusing light flux only in a single direction from a light source such as semiconductor laser, particularly related to the impact absorption structure thereof.

2. Related Background of the Invention

In a construction site, used is an optical marking device irradiating a vertical line light or a horizontal line light which is a criterion of a vertical degree and a horizontal degree of pillars and walls. Most of the light sources of the optical marking device are semiconductor lasers and are generally referred to as a laser marking device. The laser marking device suspends a mechanism referred to as a gimbal mechanism or a gyro mechanism (hereinafter referred to as “gimbal mechanism”) in a perpendicular orientation so as to always maintain a vertical position and supports a light source unit including the semiconductor laser with the above mentioned light source unit holder. The light source unit includes a semiconductor laser as a light source, a collimating lens converting dispersing light radiated from the semiconductor laser into a parallel light flux, and a rod lens dispersing the parallel flux in a single direction. The parallel light flux enters into the rod lens from a direction perpendicular to a center axis thereof and is diffused in a fan shape only in a direction perpendicular to the above mentioned center axis by refraction by the rod lens. This diffusion light is irradiated to walls, ceilings, and floors of the building so as to draw straight lines by radiated light. Then a vertical line light can be irradiated by mounting the above mentioned light source unit on the above mentioned unit holder in such way that the center axis of the rod lens is horizontal. In addition a horizontal line light can be irradiated by mounting the above mentioned light source unit on the above mentioned unit holder in such way that the center axis of the rode lens is horizontal. Such is a fundamental principle of the laser marking device.

In the laser marking device, the light source unit holder supporting the light source unit is swingably supported by the gimbal mechanism. The laser marking device is required to accurately irradiate light of a vertical or horizontal direction line. For that reason, the gimbal mechanism desirably has a low friction resistance and the light source holder is desired to be maintained in a predetermined vertical direction position. Therefore, generally a bearing portion of the gimbal mechanism mainly comprises a ball bearing and an axis rotatably supported thereby. However, since potentially the lowest friction resistance is selected for the ball bearing employed in the gimbal mechanism of the laser marking device, a problem of impact resistance exists. Therefore, even in the case that the laser marking device is erroneously dropped down during use, the bearing portion is damaged adversely affected due to impact resistance to increase the friction resistance such that the light source unit holder cannot hold the predetermined position, which thus causes a problem of deteriorated accuracy of the irradiated line light.

In view of the foregoing, there has been proposed a laser marking device comprising a first support for swingably journaling a laser beam irradiating device with a first support shaft, a second support for swingably journaling the first support with a second support shaft perpendicular to the first support shaft, and a supporting member provided with a holding portion for holding the second support, wherein the second support is held on the above mentioned holding portion in such way that interference bodies are interposed respectively on both sides along longitudinal, lateral and vertical directions of the second support (ref. to, for example, Patent Reference1, discussed below). The above mentioned “laser beam irradiation device” is the member corresponding to “light source unit holder” mentioned above. The first support shaft, the second support shaft and the second support comprise a gimbal mechanism. The above impact absorber reduces the impact otherwise applied to the above mentioned holding portion to transmit to the light source unit holder which is swingably journaled by the above mentioned gimbal mechanism, thereby reducing the damage to the gimbal mechanism.

The invention of the Patent Reference1is effective in protecting the gimbal mechanism when the laser marking device is dropped. However, the configuration of the above mentioned impact absorber of the Patent Reference1invention is required to entirely cover the exterior surface, top and bottom surfaces, and both side surfaces of the second support, which therefore increases the area and a volume of the impact absorber and thus increases the cost of the impact absorber. In addition, the volume of the laser marking device also increases due to the presence of the impact absorber. Moreover, there are many which are interfered with, such as the gimbal mechanism, the light source unit holder as well as the second support, for which impact absorbing effect should be improved. These factors also increase the volume of impact absorber.

Patent Reference 1 referred to above is Japanese Patent 2004-301756 A.

The present inventor proposes a marking device in which an impact absorber held by a support covers periphery of both ends of a shaft having a gimbal mechanism and above mentioned shaft is supported by the support through this impact absorber. That is an invention related to Japanese Patent Application 2005-64234.

According to the invention related to the above mentioned application, impact absorption effect is provided as expected. However, assuming that it is used under the severe conditions in dropping from a high location e.g. more than 1 m, it is found that even the invention related to the above mentioned application can not obtain a sufficient impact absorption effect.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a marking device which effectively reduces damage to the gimbal mechanism even when it is used under sever conditions such as being dropped from a high location, and which is durable for subsequently continuous usage.

A marking device according to the present invention comprises a support mounted inside a housing, a light source unit holder swingably suspended by this support through a gimbal mechanism, and a light source unit mounted on this light source unit holder so as to diffuse a light flux only in a single direction to radiate a line of light, wherein the above mentioned support is coupled with the above mentioned housing through a damper with an upper portion and lower portion formed of an impact absorber, such that when an outside impact is applied the above mentioned damper absorbs impact energy so as to prevent the impact from being transmitted to the above mentioned support.

The damper has a hole provided therein in an axial direction and has a small diameter portion in a middle portion in the axial direction, the above mentioned hole being penetrated at one end by a mounting shaft coupled with the housing or the support and the damper is coupled with the support, wherein the above mentioned small diameter portion is fit in with a portion substantially integrated with the support or the housing so that an upper portion and an lower portion of the support are coupled with the housing through the dampers.

The support is configured such that the lower portion is supported by the housing through the damper and the upper portion is suspended by the housing through the damper. Therefore, the support is raised from the housing by interference of the damper. When the marking device falls down or is dropped, most of the impact force applied to the housing is absorbed by the dampers in the upper portion and the lower portion of the support so that the impact force is prevented from being transmitted to the support. For this reason, the impact force transmitted from the support to the gimbal mechanism is reduced and the impact force applied to the support portion of the shaft constituting the gimbal mechanism is also reduced, such that any damage affecting the gimbal mechanism is dramatically reduced. Even if relatively large impact force is applied thereto, the device can be continuously used without readjustment and repairs.

DESCRIPTION OF THE PREFERRED EMBODIMENT

An embodiment of the marking device related to the present invention will now be described with reference to drawings.

InFIGS. 1 to 3, a cylindrical housing1has a top plate11and a bottom plate12, and a lower surface of the bottom plate12is mounted on a tripod, which is not shown, so as to be installed with the tripod in a vertically standing posture. In the housing1mounted is a support2for swingably supporting a light source unit holder4. The present invention features a structure for mounting this support2. The support2is coupled with the above mentioned housing1through dampers7and8formed of impact absorber at upper and lower portions. The upper dampers7are formed as a pair and each of the dampers7is mounted on the lower surface of the housing1with a screw17. The lower dampers8are formed as a pair and are held by a diskform mounting member10horizontally fixed to inner periphery of the housing1in the vicinity of the bottom plate12of the housing1. As shown inFIG. 3, assuming that a line connecting the centers of the lower dampers is in an X-axis direction line and a line connecting centers of the upper dampers is in a Y-axis direction line, the above mentioned X-axis direction line and Y-axis direction line cross at right angles with each other with respect to the center axis of the housing1.

Each of the above mentioned dampers7and8has the same structure andFIG. 4shows a structure of the damper7representing these dampers. InFIG. 4, the damper7is entirely formed of an impact absorber and the damper7has an axial direction hole71, a small diameter portion74around an outer periphery of axially center portion, and large diameter portions72,73sandwiching the small diameter portion74. The impact absorber forming the damper7has a characteristic such that an applied kinetic energy is absorbed by converting said energy into thermo energy and is required to have no repulsion force or a low repulsion force. There is “low repulsive rubber” as a material to meet the requirement and spongy low repulsive rubber is used in this embodiment. The above mentioned hole71is penetrated by a mounting shaft and one end of the mounting shaft is coupled with the above mentioned housing1or the above mentioned support2, so that the housing1is coupled with the support2with the above mentioned damper7being interposed therebetween. Since the structures in which the housing1and the support2are coupled with the damper interposed are different between the upper portion and the lower portion, the structure of the coupling of the housing1and the support2will be individually described next with respect to the upper portion and the lower portion.

InFIGS. 1 and 2, an extension mounting member9is extended to the upper end of the support2by appropriate means such as a screw cramp. In the extension mounting member9, an upper end portion and a lower end portion of a vertical plate are bent at a right angle in a form of a lateral U shape. In addition, a piece bent at the lower end of the mounting member9is coupled with the upper end of the support2. A piece91bent at the upper end of the extension mounting member9is formed with two arc cuts, on each of which the small diameter portion74of the above-mentioned damper7is fit, thereby mounting the damper7on the extension mounting member9substantially integrated with the support2. The hole71of each damper7is inserted with a sleeve80shown inFIG. 6. InFIG. 6, the sleeve80includes a cylindrical body portion fit in the center hole of the damper7, and a flange portion81integrally continued with one end of the body portion. The center hole71of the above mentioned damper7is fit with the body portion of the sleeve80, and the flange portion81of the sleeve80is adjacent the upper end face of the damper7. A screw17penetrating the top plate11of the housing1passes through the center hole of the body portion of the sleeve80from the upper side, and each screw17projected from the lower end face of each damper7is fit with a washer76and further screwed with a nut. Thus each damper7is mounted on the top plate11of the housing1and the upper portion of the support2is coupled with the lower face side of the top plate11through each damper7.

FIG. 5shows the mounting member10fixed to the lower portion of the housing1. As shown inFIG. 5, the mounting member10is formed out of a plane plate material into a ring shape, is provided with four mounting holes101circumferentially equally spaced at periphery of the mounting member10, and has two round holes102for mounting the damper8. The mounting member10also has a relatively big round hole103at the center of thereof. The mounting member10is sandwiched at the lower portion of the housing1and a screw13penetrating the above mentioned mounting hole101from the lower portion of the housing1is tightened and fixed to the body of the housing1. The above mentioned two round hole102of the mounting member10is fit with the small diameter portion each of the dampers8, thereby mounting the damper8on the mounting member10substantially integrated with the support2. The center hole of each damper8is inserted with the body portion of the above mentioned sleeve80from the upper side, and the flange portion81of each sleeve80is adjacent to the upper end face of the damper8. The screw15is screwed in the center hole of each sleeve80from the lower side, and the upper end portion of each screw15projected from the upper end face of each sleeve80is screwed into the bottom plate26of the support2. A washer86is interposed between the top portion of each screw15and the bottom face of the damper8present at such location. Thus each damper8is coupled with the mounting member10substantially integrated with the housing1, and the lower portion of the support2is coupled with the mounting member10substantially integrated with the housing1through each damper8.

Thus, the upper portion of the support2is coupled with the top plate of the housing1through dampers7in such mode such that the top plate of the housing I suspend the support2, and the lower portion of the support2is coupled with the lower portion of the housing1through the damper8and the mounting member10in such mode that the support2is supported upward from the lower portion of the housing1. When an impact is applied in a vertical direction in a standing posture as shown inFIGS. 1 and 2, the support2tends to cause relative movement to the housing1in a vertical direction. At this time, the large diameter portions72,73of both ends of the damper8in vertical direction are deformed and the large diameter portions82,83of both ends of the damper7in vertical direction are deformed, so that each damper7,8converts an impact force into thermal energy to reduce the impact force transmitted to the support2. When the impact force is laterally applied due to the external factor such as fall of the housing1inFIGS. 1 and 2, the support2tends to cause relative movement to the housing1in a vertical direction. In this case, the small diameter portion74of each upper damper7is pushed by the bent piece91of the extension mounting member9integrated with the support2, and the small diameter portion of each lower damper8is pushed by the mounting member10integrated with the housing1. Since the small diameter portion of each damper7,8is also formed of absorber material such as low repulsive rubber, the impact force to be transmitted to the support2is converted into thermal energy due to deformation of the small diameter portion of each damper7and8to reduce the impact force transmitted to the support2.

The center hole of each damper7,8is fitted with the sleeve80and each damper7,8can deform along a circumference of the sleeve80, thereby each damper7,8is deformed smoothly and the damping function is efficiently performed.

The dampers7,8each may be entirely and integrally formed of an impact absorber made of the same material. Since the impact force to be reduced is different in direction between the large diameter portion and the small diameter portion, different materials may be used so that the impact force is efficiently reduced based on the direction of the impact force to be reduced. In the case of different materials between the large diameter portion and the small diameter portion, different materials are arranged along the axial direction and adhered.

Next, the configuration of the light source unit holder4supported by the above mentioned support2and the gimbal mechanism3swingably suspending this light source unit holder4will be described. InFIGS. 1 and 2, a pair of bearing holders21,21are integrally formed in the upper portion of the support2. A pair of the bearing holders21,21has a cylindrical shape with bottom and open ends are opposing with each other. And the damper22,22having cylindrical shape with bottom are embedded inside the bearing holders21,21. Each damper22,22may be formed of the material having absorption function, such as the impact absorber made of low repulsive rubber as well as in the above mentioned damper7,8. Bearing23,23such as a ball bearing is fit in the bearing holder21,21through each damper22,22, and a shaft25is rotatably supported by the bearing23,23.

An intermediate swinging frame40is swingably supported around the above mentioned shaft25. The intermediate swinging frame40is integrally formed with a pair of bearing holders45,45. Each of the bearing holders45,45has a cylindrical shape with bottom and open ends are opposing to each other. The dampers44,44each have a cylindrical shape which is embedded inside each bearing holder45,45. The impact absorber made of low repulsive rubber may be used as a material of each damper44,44similarly as for the above mentioned damper7,8. Bearings43,43such as a ball bearing are fitted in the bearing holder45,45through each damper44,44, and a shaft41is rotatably supported by the bearings43,43. The shaft41is supported on the upper side of the above mentioned shaft25in a direction perpendicular to the shaft25. The shaft41suspends the light source unit holder4which is swingable around the shaft41. The above mentioned bearing23,43, the shaft25,41, and the middle swinging frame40constitutes the gimbal mechanism3, through which the support2swingably suspends the light source unit holder4. The above mentioned shaft25penetrates the light source unit holder4and a relief hole46for the shaft25is formed in the light source unit holder4so that the shaft25does not obstruct the light source unit holder4swinging around the shaft41.

A light source unit5is mounted on the upper end portion of the light source unit holder4and a light source unit6is mounted in the middle portion in vertical direction and under the above mentioned shaft25. The light source unit5irradiates a vertical line of light and includes a unit case51and a rod lens52mounted on the upper end of the unit case51. A semiconductor laser is mounted as a light source in the unit case51and a collimating lens for collimating diffusion light radiated from the semiconductor into parallel light flux is mounted. In the configuration, the above mentioned parallel light flux enters in a direction perpendicular to the center axis line with respect to the rod lens52, and the rod lens52diffuses and outputs the parallel light flux only in a direction perpendicular to the center axis line. When the light source unit holder4is in the predetermined hanging position, the rod lens52of the light source unit5is in a horizontal direction and designed to irradiate the vertical light line. The light source unit5is configured to be mounted pointing obliquely upwards on the light source unit holder4to irradiate the line light from walls to ceilings of the building for example.

The other light source unit6irradiates a horizontal line of light and includes a unit case61and a rod lens62mounted to the end of this unit case61. The unit case61is provided with semiconductor laser as a light source and a collimating lens for collimating diffused light radiated from the semiconductor laser into parallel light flux. In this configuration, the above mentioned parallel light flux enters in a direction parallel to the center axis line with respect to the rod lens62and the rod lens62diffuses and outputs the parallel light flux in a direction perpendicular to the center axis line. When the light source unit holder4is in the predetermined hanging position, the light source unit6is mounted pointing in a horizontal direction and the rod lens62of the light source unit6is oriented in vertical direction to irradiate horizontal line light.

The light source unit holder4is provided with a braking plate42in the lower end portion thereof. The braking plate42is to brake swinging of the light source unit holder4due to magnetic action, and is formed in such way that a swinging direction with the above mentioned shaft25as a center forms an arc following a swinging trait and formed to extend to both sides of the light source unit holder4. A swinging direction of the above mentioned braking plate42with the above mentioned shaft as a center is formed in an arc following the swing trait. The material of the light source unit holder4is not particularly specified but at least a portion of the braking plate42is formed of conductive material. The upper face of the bottom plate26of the above mentioned support2is fixed with the appropriate number of magnets50appropriately spaced with respect to the above mentioned braking plate42. Each magnet50is arranged through the appropriate yoke in such way that the magnet50is declined to cope with the arc face of the braking plate42to correspond the above mentioned braking plate42with the arc face. The braking plate42is located within a magnetic field formed by respective magnets50. When the light source unit holder4is swung by the gimbal mechanism3, the braking plate42crosses the line of magnetic force of the magnetic field to generate eddy current to the braking plate42. With this eddy current, driving force (torque) is generated in a direction opposite to the swing direction of the light source unit holder4. Therefore, this driving force functions as a force to stop the swing of the light source unit holder4, and quickly stop the light source unit holder4.

Thus the configuration of the embodiment shown in the drawings is as described above. Next, the action and effect of the above mentioned embodiment will be described. It is assumed that the marking device is applied with exterior impact for some factors such as dropping or falling down. As mentioned above, with regard to the vertical impact force, the large diameter portions in the both ends in vertical direction of dampers7,8in the upper portion and the lower portion are deformed, whereby the dampers7,8converts impact force into thermal energy to reduce impact force transmitted from the housing1to the support2. With respect to horizontal impact force the small diameter portion of the dampers7,8in the upper and the lower portion is pushed by a bent piece91of the extension mount member9and the deformation of each small diameter portion converts the impact force to reduce the impact force to be transmitted from the housing1to the support2. Since the support2is mounted in such way that the upper portion and the lower portion of the support2are raised from the housing1due to interference of the dampers7and8, the outside impact force is absorbed by respective dampers7,8, thereby the impact force transmitted from the housing to the support2can be dramatically reduced. The impact force applied to the gimbal mechanism3supporting the support2can be also reduced, damage to the gimbal mechanism caused by the outside impact force can be reduced, and accuracy distortion caused by the impact force applied to the marking device can be dramatically reduced. Therefore, it is durable even for rough handling, can be continuously used without readjustment or repair even if relatively big impact force is applied, and chances of readjustment or repair can be reduced.

An object of the present invention can be achieved by coupling the upper portion and the lower portion of the support2with the housing1through dampers7and8made of impact absorber. In addition to this, the shafts25and41constituting the gimbal mechanism3are supported through the dampers22and44as in the embodiment in the drawing so that damage applied to the shafts25and41of the gimbal mechanism3caused by outside impact force can be further efficiently reduced. Distortion of the accuracy due to the impact force can be efficiently reduced and chances of readjustment and maintenance can be reduced.

The damage applied to the shafts25and41of the gimbal mechanism3includes deformation of the bearing supporting the shafts25and41as well as bending and deformation of the shafts25and41. When the shafts25and41of the gimbal mechanism3are subject to damage, the gimbal mechanism3does not operate smoothly and the light source unit holder4can not hold the predetermined hanging position, thereby causing uneven static positioning of the light source unit holder4. As a result, line light irradiated from the light source units5and6is not in vertical direction or horizontal direction.

With this respect, with the present invention, since damage of the shaft of the gimbal mechanism due to the impact force can be reduced further efficiently, distortion of degree of the vertical line light and the horizontal line light can be prevented even if relatively big impact force is applied.

Although two dampers are provided respectively with regard to dampers7and8in the upper portion and the lower portion in the embodiment in the drawing, the number of dampers in the upper and lower portions is arbitrary. For example, in the upper portion and the lower portion, a plurality of dampers may be arranged in one portion and a single damper may be arranged in the other portion. Further, three dampers may be arranged at least one portion and the dampers may be supported by support at three points.

As shown in the embodiment of the drawing, the upper portion and the lower portion each has a pair of dampers, and dampers are arranged in such way that a line connecting the centers of two dampers in the upper portion and a line connecting centers of two dampers in the lower portion are perpendicular with each other. Then the support is prevented from declining in one side and the support can be stably supported.