Optical device knob having variable resistance to rotation

An optical device housing has a post rotatably extending therefrom and a sleeve fixedly extending therefrom. The sleeve is disposed around the post. A knob is connected to the post. A clutch mechanism includes: a friction element movably engaged with the sleeve; a friction surface; and an adjustment element engaged with the friction element and rotatable relative to the optical device housing and the knob housing. Rotation of the adjustment element selectively engages the friction surface with the interior surface.

Aiming a rifle or gun requires the consideration of several environmental and other types of factors. When a bullet travels from a rifle to an intended target, several forces affect the flight of the bullet. Gravity causes the bullet to drop in elevation as the bullet travels from the firearm to the target. If a hunter100is close to his/her target102, as shown inFIG. 1A, the bullet drops very little, represented by the trajectory104. At greater distances, gravity causes a bullet to drop in elevation more significantly, as represented by the trajectory106inFIG. 1B. An optical device such as a riflescope is used to accurately aim the rifle.

SUMMARY

In one aspect, the technology relates to an apparatus having: an optical device housing; a post rotatably extending from the optical device housing; a sleeve fixedly extending from the optical device housing and disposed about the post; a knob connected to the post so as to be rotatable relative to the optical device housing, the knob having a knob housing having an interior surface; and a clutch mechanism having: a friction element movably engaged with the sleeve; a friction surface; and an adjustment element engaged with the friction element and rotatable relative to the optical device housing and the knob housing, wherein a rotation of the adjustment element selectively engages the friction surface with the interior surface. In an example, the post includes a post axis and wherein each of the post, the sleeve, the knob housing, the friction element, and the adjustment element are centered about the post axis. In another example, the sleeve includes a sleeve projection extending away from the post axis, and wherein the friction element is disposed about the sleeve and includes a friction element projection engaged with the sleeve projection, wherein an engagement between the sleeve projection and the friction element projection prevents rotation of the friction element relative to the sleeve. In yet another example, the friction element projection is slidable relative to the sleeve projection in a direction along the post axis. In still another example, the adjustment element includes a ramp engaged with the friction element, such that a rotation of the adjustment element moves the friction element along the post axis.

In another example of the above aspect, the ramp is engaged with a surface of the friction element disposed substantially opposite the friction surface. In an example, the ramp is engaged with a surface of the friction element disposed substantially opposite the friction element projection. In another example, the friction surface is discrete from the friction element.

In another aspect, the technology relates to an apparatus including: an optical device housing; a post rotatably extending from the optical device housing; a sleeve fixedly extending from the optical device housing and disposed about the post, wherein the post and sleeve are centered on a common axis; a knob connected to the post so as to be rotatable relative to the optical device housing; a friction element non-rotatably engaged with the sleeve and slidably engaged with the sleeve so as to slide along the sleeve relative to the common axis; and a position adjustment element engaged with the friction element, wherein a rotation in a first direction of the position adjustment element selectively increases a frictional resistance between the knob and the friction element. In an example, a rotation in a second direction of the position adjustment element selectively decreases the frictional resistance between the knob and the friction element. In another example, the rotation in the second direction entirely disengages the friction element from the knob. In yet another example, the position adjustment element extends beyond an outer surface of the knob. In still another example, the friction element is substantially ring-shaped and is disposed around the sleeve.

In another example of the above aspect, the position adjustment element is substantially ring-shaped and is disposed around the friction element. In an example, the position adjustment element is substantially ring-shaped and is disposed opposite the friction element from the knob. In another example, each of the knob, the post, the sleeve, the friction element, and the position adjustment element are centered on the common axis.

In another aspect, the technology relates to an apparatus having: an optical device housing; a post rotatable about an axis extending from the optical device housing; a sleeve fixedly extending from the optical device housing and disposed about the post, wherein the post and sleeve are centered on an axis; a knob connected to the post so as to be rotatable relative to the optical device housing; a clutch disposed about the sleeve; and a cam engaged with the clutch, wherein a rotation of the cam moves the clutch into engagement with the knob. In an example, in a first cam position, the clutch is disengaged from the knob. In an example, in a second cam position, the clutch engages the knob at a first frictional resistance. In another example, in a third cam position, the clutch engages the knob at a second frictional resistance greater than the first frictional resistance.

DETAILED DESCRIPTION

The present technology relates to new and improved embodiments of known sighting systems and methods (such as those described in U.S. Pat. No. 7,703,679, the disclosure of which is hereby incorporated by reference herein in its entirety), for correctly aiming a firearm or other implement. As used herein, a “sighting system” shall be construed broadly and is defined as one or more optical devices and processing systems that assist a person in aiming a projectile launch system, such as a firearm, a rifle, a handgun, or other implement. The disclosed technology has application in any type of sighting system or optical device, including those with addressable aiming elements and those without. In this application, a riflescope will be described as an exemplary embodiment.

A hunter, sniper, or other person using a rifle or other firearm, commonly referred to as a shooter, uses optical sighting systems, such as riflescopes, to visually acquire a target and improve aiming accuracy.FIGS. 2A and 2Bdepict partial perspective and partial exploded perspective views of an optical device200in the form of a riflescope. These two figures are described concurrently. The optical device200utilizes an adjustment knob202that is used to adjust one or more settings of the optical device. The optical device200includes a housing204having a longitudinal axis A, as well as an ocular end206and an objective end208(an ocular bell housing and lenses are not depicted inFIGS. 2A and 2B). A reference mark210is disposed on a surface of the housing204, proximate a knob mount212. The knob mount212is secured to the housing204and defines a location upon which the knob202rests when attached to an adjustment post214. The adjustment post214includes a neck216sized so as to receive a plurality of set screws (not shown) disposed in openings218defined by the knob202. The adjustment post214is rotatably mounted relative to the housing204. Once the knob202is secured to the adjustment post214, rotation of the knob202rotates the adjustment post214, so as to adjust a sighting system disposed in the housing204(e.g., moving lenses or reticles, or changing other optical settings of the sighting system, as known in the art).

The knob mount212may include a sleeve220that is fixedly secured relative to the housing204(e.g., via the knob mount212), so as not to rotate relative thereto. A clocking pin222extends from the sleeve220and is fixed so as not to move upon rotation of the knob202. The clocking pin222prevents overrotation of the knob202. The knob202includes a plurality of reference markings224, typically in the form of tick marks or lines disposed about an outer circumference of the knob202. Rotation of the knob202aligns different reference markings224with the reference mark210on the housing204, thus providing a visual indication to the shooter of a setting of the optical device200. Once a desired position of the knob202(relative to the housing204) is set, it may be desirable for the shooter to set this position of the knob202, so as to avoid inadvertent rotation thereof. Such an inadvertent rotation, if unnoticed, may change a setting of the optical device200, potentially causing an inaccurate later shot by the associated rifle.

Accordingly, the optical devices described herein utilize knobs that are configured to variably resist rotation by utilizing structure that selectively increases and decreases the frictional resistance of the knob. This can reduce or prevent the likelihood of rotation of the knob. Additionally, the frictional resistance may be varied so the knobs may be turned easily or with difficulty, as required or desired by a particular shooter. For example, when zeroing the knob (e.g., after a successful shot), a shooter may want little to no additional resistance applied to the knob so as to enable a faster rotation. When precise rotation of the knob is required, the shooter may set the frictional resistance of the knob to a desired setting, so as to prevent, e.g., inadvertent over-rotation thereof. When a desired position is attained, the frictional resistance may be further increased so as to set the knob against inadvertent rotation in the desired position. The variable friction knobs described herein, however, need not wholly prevent rotation once set. So-called “locking knobs” available in the prior art often include elements that physically engage in such a way that a high force applied to the knob can break the locking mechanism, causing damage to the knob that requires repair or replacement. The variable friction knobs described herein, however, resist rotation applied up to a certain force. Higher forces, however, will cause rotation of the knob, without damage to the mechanism that resists rotation. As such, the variable friction knobs are more versatile and less prone to damage than many prior art locking knobs.

Relative toFIGS. 2A and 2B, then, the optical device includes a friction adjustment element226, here in the form of a crenellated ring disposed proximate the knob202. The knob202is independently rotatable relative to the friction adjustment element226. Similarly, the friction adjustment element226is independently rotatable relative to both the knob202and the housing204, whereby rotation of the adjustment element226to adjust the frictional resistance of the knob202does not rotate the knob202. Additionally, when a desired position of the knob202is attained, the adjustment element226may be rotated to set a friction level sufficient to maintain that position, again without rotation of the knob202itself. InFIGS. 2A and 2B, only a single knob202of multiple knobs on the optical device200is depicted as including a friction adjustment element226. Any number of knobs on a given optical device may incorporate the technologies described herein.

FIG. 3depicts an exploded perspective view of a variable friction knob300. Also depicted, for context, is a portion of an optical device200, notably, a fixed knob mount212and components extending therefrom. More specifically, a sleeve220and a clocking pin222fixedly extend from the knob mount212. A post214rotatably extends from the sleeve220. The sleeve220also includes one or more sleeve projections250about an outer circumference thereof. In the depicted example, a plurality of sleeve projections250are in the form of a plurality of teeth extending away from a common central axis AC, which is defined by the post214and about which the post214rotates.

The variable friction knob300includes a knob housing302that has a gripping portion304, which may be knurled or otherwise textured to provide a secure gripping surface. As described above, the knob302also defines a plurality of openings306for receiving set screws (not shown). Reference markings308are also depicted on the exterior surface310of the housing302. The reference markings308may additionally include alphanumeric indicia or other symbols. In another example, the knob300may incorporate the multi-turn knob technologies described in U.S. Pat. No. 9,423,215, the disclosure of which is hereby incorporated by reference herein in its entirety. A top surface312of the knob housing302seals the knob300against intrusion of dirt, debris, rainwater, or other containments that may be found in the field.

The variable friction knob300also includes a clutch mechanism312that may be utilized to vary the amount of frictional resistance to rotation of the knob housing302, certain benefits and advantages of which are described above. The clutch mechanism312includes a clutch or friction element314, which in the depicted example is substantially ring-shaped and has an inner surface defining one or more toothed projections316. The toothed projections316are configured to engage with the plurality of sleeve projections250, thus preventing the friction element314from rotating about axis AC. The mating projections316,250are configured so as to allow the friction element314to slide relative to the sleeve220along and substantially parallel to the axis AC, as described below. The friction element314includes a friction surface318, which in the depicted example is a substantially flat upper surface, although other configurations are contemplated and described herein. For example, the friction element314can be a high strength material, such as metal, topped with a high friction material. The high friction material may define the friction surface318and be discrete from or adhered to (or even integral with) the friction element314. Additional coatings or textures may be applied to or formed on the friction surface318as required or desired to further increase the coefficient of friction thereof.

The friction element314also includes one or more threads, cams, or ramps320disposed on an outer surface thereof. The ramps320are configured to engage with matching threads, cams, or ramps322disposed on an interior surface of an adjustment element324. The adjustment element324may also be substantially ring-shaped and disposed about the friction element314. As such, a first directional rotation R of the adjustment element324produces a first linear movement M of the friction element314, while a second opposite directional rotation R′ produces a second linear movement M′ of the friction element314. These rotations R, R′ and corresponding movements M, M′ adjust the frictional resistance of the knob300, as described in more detail below. To rotate R, R′ the adjustment element324, a shooter applies a force to one or more of the crenellations326that project from a side of the adjustment element324. These crenellations326project beyond the exterior surface310of the knob housing302to enable easy access and rotation R, R′.

The position of the friction element314, relative to the knob housing302, as described in further detail below, determines the frictional resistance of the knob300to rotation. When the friction element314is not in contact with the knob housing302, no additional frictional resistance is applied to the knob300. As the friction element314first contacts the knob housing302, then applies a greater force thereto, the resistance to rotation of the knob300increases. In order to balance the various forces, the various components of the knob300are arranged so as to be substantially centered about the common axis ACthat extends from the post214. More specifically, the post214rotates about the common axis AC, while the sleeve220is disposed about the post214and is fixedly secured to the knob mount212so as to not rotate about the axis AC. The friction element314is disposed about the sleeve220and engaged therewith so as to not rotate about the axis AC. The adjustment element324is disposed about the friction element314. A portion of the knob housing302is disposed about the adjustment element324, while leaving the crenellations326exposed. The centers of all of these elements are aligned along the common axis AC.

FIG. 4depicts a sectional view of a variable friction knob300, such as that depicted inFIG. 3. A number of the components depicted inFIG. 4are described above in preceding figures, and are therefore not necessarily described further. The knob mount212is secured to the housing of an optical device (not shown) so as not to rotate. An extension element402penetrates the knob mount212and extends into the optical device housing. Movement thereof (either rotational or linear movement, as required or desired for a particular application), adjusts an optical setting of the optical device. In the depicted example, a set pin404extends from the post214into the extension402, such that rotation of the post214is transferred to the extension402, thus causing a corresponding rotation thereof. A clicker408is biased away from the axis ACby a spring410and into a detent surface412(contact between the clicker408and detent surface412is not depicted inFIG. 4for clarity). The clicker408and detent surface412aids in setting a position of the knob housing302such that the reference markings (not depicted) on the exterior surface310thereof align with the reference mark (not depicted) on the optical device housing.

The post214extends upwards from within sleeve220and is configured to rotate relative thereto, about the common axis AC. The knob housing302is secured to the post214via a set screw (not depicted) inserted into the opening306so as to engage the neck216in the post214. Multiple set screws may be utilized. As described above, the sleeve220includes one or more sleeve projections250that extend away from the common axis AC. The sleeve projection250engages with a mating projection316, e.g., a toothed projection, extending from an inner surface of the friction element314. Note that inFIG. 4, the sleeve projection250is depicted as extending into the friction element314, in a position proximate where the mating projection316is located. The mating projection316is not depicted, for clarity. The adjustment element324is configured to rotate independent of knob housing302and the post214, so as to enable adjustment of the frictional resistance to rotation of the knob housing302. InFIG. 4, the friction element314is not in contact with the knob housing302. More specifically, the friction surface318is not engaged with an interior engagement surface416of the knob housing302. As such, there is a no additional frictional resistance applied to the knob housing302by the friction element314and the knob housing302is easiest to rotate. As the adjustment member324is rotated R about the axis AC, the interface418(inFIG. 4, the threaded or ramped structure of the interface418is not depicted, for clarity) between the adjustment member324and the friction element314causes the friction element314to move M upward, substantially along and parallel to the common axis AC. This movement allows the shooter to selectively engage the friction surface318with the interior engagement surface416, thus increasing the frictional resistance to rotation of the knob302. Further rotation R of the adjustment element324increases the frictional resistance. As described above, however, since the friction surface318and interior engagement surface416are generally flat surfaces and do not utilize engaging parts such as detents, locking projections, and the like, sufficient rotational force may still overcome the set frictional resistance. As such, the knob300resists rotation that may occur inadvertently due to incidental contact (e.g., during movement of the rifle in the field), but will not be damaged if a significant rotational force is applied to the knob housing302. When a shooter wishes to reduce the frictional resistance, the adjustment element324is rotated R′ in an opposite direction so as to move M′ the friction element314downward.

FIGS. 5A-5Bdepict enlarged partial section views of the variable friction knob300ofFIG. 4. A number of the components depicted inFIGS. 5A and 5Bare described above in preceding figures, and are therefore not necessarily described further.FIG. 5Adepicts the friction element314in a position so as to exert no additional frictional resistance against the interior surface416of the knob housing302. Thus, the knob300is free to turn. As depicted inFIG. 5B, since the adjustment element324has been rotated, the engagement of the friction element314and the adjustment element324at the interface418caused an upward movement of the friction element314. Once the friction surface318contacts the interior surface416of the knob housing302, the frictional resistance between the friction element314and the interior surface416increases. Thus, since the friction element314is non-rotatably engaged with the sleeve220at the projections316,250, resistance to rotation of the knob housing302increases. The adjustment element324may be further rotated so as to apply a greater force by friction element314to the interior surface416, this increasing the frictional resistance of the knob housing302to rotation. This increase in frictional resistance may be accompanied with compression of the friction element314against the interior surface416.

FIG. 6A-6Cdepict partial side sectional views of a variable friction knob500, which includes, schematically depicted, a knob housing502, a clutch or friction element504, and an adjustment element506. The knob housing502has an interior surface508and the friction element has a friction surface510including a number of wave-like projections512. Projections having other shapes are contemplated. For example, such projections may be discrete bumps or domes projecting from the friction surface510, or may be toothed or crenellated projections. The friction element504and the adjustment element506are engaged at a cammed or ramped interface514disposed on a surface of the friction element504opposite the friction surface510. InFIG. 6A, the friction element504is not engaged with the knob housing502. As such, the friction element504applies no frictional resistance to the knob housing502. InFIG. 6B, the adjustment element506has been rotated R, which moves M the friction element504upward, due to the engagement between those elements at the ramped interface514. This upward movement would be substantially parallel to the common axis depicted previously. This causes contact between the wave-like projections512of the friction surface510and the interior surface508, thus applying a force F to the knob housing502and increasing the frictional resistance to rotation of the knob500. InFIG. 6C, the adjustment element506has been further rotated R+, which further moves M+ the friction element504upward. This causes compression of the wave-like projections512and increases the contact area between the friction surface510and the interior surface508, thus applying a greater force F+ to the knob housing502, further increasing the frictional resistance to rotation of the knob500. Rotation R− in the opposite direction (also depicted inFIG. 6C), moves M− the friction element504in an opposite direction, reducing the force F− applied to the knob housing502. This decreases the frictional resistance to rotation of the knob500. Further opposite rotation R− of the adjustment element506returns the friction element504to the non-contacting condition depicted inFIG. 6A, where the friction element504is entirely disengaged from the knob housing502.

FIGS. 7A-7Bdepict enlarged partial section views of another example of a variable friction knob600for an optical device. Specifically,FIGS. 7A-7Bdepict a variable friction knob600that utilize a friction element602that lacks an integral friction surface. Instead, the friction surface is in the form of a discrete (relative to the friction element602) friction ring604that may be connected to the housing606, or discrete therefrom, as depicted. The friction element602is slidably engaged with a sleeve608, as described above. Additionally, an adjustment element610is disposed in this case below the friction element602.FIG. 5Adepicts the friction element602in a position so as to exert no additional frictional resistance against the knob housing606, since it is not engaged with the friction ring604. Thus, the knob600is free to turn. As depicted inFIG. 5B, since the adjustment element610has been rotated, a ramp612thereon pushes the friction element602upward, along the sleeve608. The wedge-shaped configuration of the friction element602applies a force (e.g., an outward force) to the friction ring604, pushing that element out into contact with the housing606, thereby adjusting the frictional resistance to rotation of the knob600. The adjustment element610may be further rotated so as to apply a greater force by friction element602to the friction ring604, this increasing the frictional resistance of the knob housing606to rotation. This increase in frictional resistance may be accompanied with compression of the friction ring604against the housing606.

The materials utilized in the manufacture of the variable friction knobs depicted therein are similar to those typically used in manufacture of knobs for optical devices. For example, the knob housings and other components may be aluminum or other robust metals and may be powder coated or otherwise treated to resist corrosion. The adjustment element may be low-friction material such as PVC, ABS, nylon, or other plastics. Additionally, metals may be used and may be coated with Teflon or other low-friction coatings at the interface between the adjustment element and friction element to ensure smooth movement of the interface therebetween. The friction element may include higher friction materials such as dry rubber, foam rubber, silicone, or sintered metal. In other examples, the friction element may be manufactured of a low friction material and may have an upper friction surface manufactured of a different, higher friction material, or may be textured or treated to display a higher coefficient of friction.

While there have been described herein what are to be considered exemplary and preferred embodiments of the present technology, other modifications of the technology will become apparent to those skilled in the art from the teachings herein. The particular methods of manufacture and geometries disclosed herein are exemplary in nature and are not to be considered limiting. It is therefore desired to be secured in the appended claims all such modifications as fall within the spirit and scope of the technology. Accordingly, what is desired to be secured by Letters Patent is the technology as defined and differentiated in the following claims, and all equivalents.