Dual speed focusing mechanism

Abstract

A dual speed focusing mechanism includes a base having an inner guide, a carriage disposed within the inner guide, a first driver, an outer guide, and a second driver. First and second bearings are disposed in respective inner pockets of the carriage, and the second bearing is disposed within a first pocket of the first driver. The first and second bearings are held within respective inner and outer slots and the first and second guides, wherein rotation of the second driver is translated into axial movement of the carriage at different rates.

Description

Technical Field

[0001] This patent application claims priority to U.S. Patent Application No. 17 / 120,602, filed December 14, 2020, pursuant to 35 USC § 120, the entire contents of which are incorporated herein by reference.

[0002] This invention relates to a dual-speed focusing mechanism. Specifically, the focusing mechanism is configured to convert rotational motion into axial displacement of the lens at two different rates. Background Technology

[0003] Focusing mechanisms used in instruments such as cameras and microscopes are known. In some cases, the focusing mechanism is a dual-speed mechanism. A dual-speed mechanism includes a first-rate mechanism and a second focusing mechanism, wherein the first-rate mechanism is configured to generate a speed at which the lens travels at a first speed, and the second focusing mechanism is configured to generate a speed at which the lens travels at a second speed. The second speed is slower than the first speed.

[0004] This mechanism is intended to allow the user to quickly adjust the focus at a first rate and slowly at a second rate. Naturally, the user rotates a knob, which moves the lens at the first rate past the ideal focus point, and then adjusts the focus by rotating a second knob, thus moving the lens back at the second rate and bringing the image to the ideal focus. The first rate is often referred to as the coarse focus adjustment rate, while the second rate is often referred to as the fine focus adjustment rate.

[0005] Currently, this focusing mechanism has two separate controls for each speed. In other aspects of conventional dual-speed focusing mechanisms, a single knob is used to actuate the worm gear, which can be operable to convert the rotation of the spur gear into fine focus adjustment. However, this configuration requires additional packaging space because the spur gear is radial relative to the worm gear.

[0006] Therefore, it is still desirable to have a focusing mechanism configured to provide dual-speed focusing, wherein the focusing mechanism uses a single rotational motion to focus the lens at two different rates, and wherein the components are contained along a linear axis and configured to be held within the packaging space of the lens housing. Summary of the Invention

[0007] A dual-speed focusing mechanism is provided. This mechanism is configured to convert rotational motion into axial displacement of the lens at two different rates. The dual-speed mechanism includes a base. The base has an inner guide. The inner guide is a tubular member with an inner slot.

[0008] The dual-speed focusing mechanism also includes a carrier. The carrier is disposed within the inner guide, and its outer surface has a dimple. The first actuator is a tubular member concentric with the inner guide. The inner surface of the first actuator includes a first groove. The first groove is helical and has a first pitch and the outer surface of the first actuator. The first actuator also includes the first dimple.

[0009] The dual-speed focusing mechanism also includes an outer guide member. The outer guide member is a tubular member concentric with the first actuator. The outer guide member includes an outer slot. The second actuator, also a tubular member, is concentric with the outer guide member. The second actuator has an inner surface having a second groove. The second groove is helical and has a second pitch smaller than the first pitch.

[0010] The dual-speed focusing mechanism also includes a first bearing and a second bearing. The first bearing is disposed within the recess, the inner slot, and the first groove. The second bearing is disposed within the first recess, the outer slot, and the second groove. The rotation of the second actuator causes the carriage to translate axially at different rates.

[0011] On the one hand, the first pitch is twice the size of the second pitch.

[0012] On the other hand, the dual-speed focusing mechanism includes a first gasket that defines the outer surface of the inner guide.

[0013] In another aspect of the dual-speed focusing mechanism, the bracket includes a lens.

[0014] In another aspect of the dual-speed focusing mechanism, the inner guide includes a pair of inner slots.

[0015] In another aspect of the dual-speed focusing mechanism, the outer slot is shorter than the inner slot.

[0016] In another aspect of the dual-speed focusing mechanism, the first pitch is variable such that the center of the first groove is larger than the end of the first groove.

[0017] In another aspect of this disclosure, a focusing mechanism for a camera is provided. The focusing mechanism includes a base having an inner guide. The inner guide is a tubular member having an inner slot.

[0018] The focusing mechanism also includes a lens cell. The lens cell is disposed within the inner guide. The outer surface of the lens cell has a recess. The focusing mechanism also includes a first actuator, which is a tubular member concentric with the inner guide. The inner surface of the first actuator includes a first groove. The first groove is helical and has a first pitch. The outer surface of the first actuator includes the first recess.

[0019] The focusing mechanism includes an outer guide. The outer guide is a tubular member concentric with the first actuator. The outer actuator includes an outer slot.

[0020] The focusing mechanism includes a second actuator. The second actuator includes a tubular member concentric with the outer actuator. The inner surface of the second actuator includes a second groove. The second groove is helical and has a pitch smaller than the first pitch.

[0021] The first bearing is disposed within the recess, the inner slot, and the first groove. The second bearing is disposed within the first recess, the outer slot, and the second groove. The rotation of the second actuator causes the lens unit to translate axially within the inner and outer guide members at different rates.

[0022] On the one hand, the first pitch is at least twice the size of the second pitch.

[0023] On the other hand, the first washer defines the outer surface of the inner guide.

[0024] On the other hand, the lens unit includes a lens.

[0025] On the other hand, the inner guide includes a pair of inner slots.

[0026] On the other hand, the outer slot is shorter than the inner slot.

[0027] On the other hand, the first pitch is variable such that the center of the first groove is different from the end of the first groove.

[0028] Therefore, a focusing mechanism is provided that allows the user to adjust the focus at two different rates using a single rotating mechanism, and is compact and configured to be packaged within a lens housing. Attached Figure Description

[0029] Figure 1 This is a perspective view of the dual-speed focusing mechanism according to the principle of the present invention.

[0030] Figure 2 yes Figure 1 An exploded view of the dual-speed focusing mechanism shown.

[0031] Figure 3 yes Figure 2 A cross-sectional view taken along line 3-3;

[0032] Figure 4A yes Figure 1 A cross-sectional view of the dual-speed focusing mechanism that makes coarse focus adjustment is shown;

[0033] Figure 4B yes Figure 1 A cross-sectional view is shown of the distal end of the first bearing of the dual-speed focusing mechanism pressing against the outer slot;

[0034] Figure 5 Yes Figure 4AThe image shows a depiction of the dual-speed focusing mechanism at one end of the fine focus adjustment.

[0035] Figure 6 A dual-speed focusing mechanism is described in the process of fine focus adjustment;

[0036] Figure 7 The dual-speed focusing mechanism displays the view at the other end of the fine focus adjustment; and

[0037] Figure 8 yes Figure 3 A view of the first groove with variable pitch is shown. Detailed Implementation

[0038] The dual-speed focusing mechanism includes a base with an inner guide, a bracket disposed within the inner guide, a first actuator, an outer guide, and a second actuator. A first bearing and a second bearing are disposed in corresponding recesses of the bracket and a first recess of the first actuator. The first bearing and the second bearing are also disposed in corresponding first and second grooves of the first and second actuators. The first bearing and the second bearing are also disposed in corresponding inner and outer slots of the inner and outer guides. The focusing mechanism is configured to convert rotation of the first actuator into axial movement of the bracket within the inner slot, wherein the second bearing is configured to convert rotation of the second actuator into axial displacement of the bracket at different rates.

[0039] First refer to Figure 1 and Figure 2 An illustrative description of the dual-speed focusing mechanism 10 is provided. Figure 2 yes Figure 1 An exploded view of mechanism 10 is shown. Mechanism 10 includes a base 12, an inner guide 14, a bracket 16, a first actuator 18, an outer guide 20, a second actuator 22, a first bearing 24, and a second bearing 26.

[0040] The base 12, bracket 16, first actuator 18, outer guide 20, and second actuator 22 may be made of a durable and rigid material that may be incorporated into the injection molding or stamping process. Materials applicable herein illustratively include polypropylene, polyoxymethylene, polycarbonate, aluminum, steel, etc. Preferably, the first and second bearings 24, 26 are formed of a durable and rigid material such as steel.

[0041] The inner guide 14 is a generally tubular member with a constant diameter. The inner guide 14 has an open end 14a. The inner guide 14 is rigidly mounted to the base 12 to form a closed end opposite the open end 14a. Optionally, the closed end may be open to allow an image to pass through and reach an image sensor or similar sensor. The inner guide 14 also includes an inner slot 28 extending along a first length L1. The inner slot 28 may extend through the wall of the tubular member and extends parallel to the longitudinal axis of the inner guide 14.

[0042] The bracket 16 is also a tubular member with a constant diameter. The diameter of the bracket 16 is smaller than the diameter of the inner guide 14 and is configured to be slidably disposed within the inner guide 14. The bracket 16 is open at both ends to provide a light path. The outer surface of the bracket 16 includes recesses 30.

[0043] The first actuator 18 is a generally tubular member with a constant diameter and open at both ends. The first actuator 18 is configured to slide on and concentrically align with the inner guide 14. The inner surface 18a of the first actuator 18 includes a first groove 32. The first groove 32 is a helical groove with a first pitch “P1”. The outer surface 18b of the first actuator 18 includes a first recess 34.

[0044] The outer guide 20 is also a generally tubular member, with a length generally longer than the first actuator 18 but shorter than the inner guide 14. The outer guide 20 is configured to be located on and concentric with the first actuator 18. The outer guide 20 includes an outer slot 36. The outer slot 36 has a second length L2 shorter than the length of the inner slot 28. The outer slot 36 extends through the wall of the tubular member and extends parallel to the longitudinal axis of the outer guide 20.

[0045] The second actuator 22 is a tubular member with a constant diameter. The second actuator 22 is concentric with the outer guide member 20. The second actuator 22 includes an inner surface 22a having a second groove 38. The second groove 38 is helical and has a second pitch "P2" smaller than the first pitch "P1".

[0046] For reference Figure 3 and Figures 4A-7 This provides a description of the assembly of the dual-speed focusing mechanism 10. A bracket 16 is configured to hold optical devices such as a lens unit 40. In one aspect, the bracket 16 includes a pocket 42 defined by an inner edge defining an inner surface of the bracket 16. The lens unit 40 is located in the pocket 42. It should be understood that other optical devices, such as filters, may be disposed within the bracket 16. The bracket 16 can be used to move the lens unit 40 to better focus an image onto an image sensor (not shown) disposed in the base 12.

[0047] like Figure 3 As shown, in a preferred aspect, the inner guide 14 includes a pair of inner slots 28, which are diametrically opposed to each other and are the same size. A bracket 16 is disposed within the inner guide 14. The mechanism 10 may include a pair of first bearings 24 and a pair of recesses 30. The recesses 30 are diametrically opposed to each other and are disposed on the outer surface of the bracket 16. The recesses 30 are generally hemispherical, and their radii are approximately the same as the radii of the first bearings 24.

[0048] The first bearing 24 is received (or captured) within the recess 30. Therefore, during assembly, the first bearing 24 is positioned or surrounds (or captured) within the corresponding inner slot 28, and the axial movement of the bracket 16 is constrained by the length of the inner slot 28. In other words, the first bearing 24 travels along the length of the inner slot 28 and carries the bracket 16 therein. The first bearing 24 is also positioned within the first recess 32 of the first actuator 18. As shown, the first actuator 18 is concentric with and covers the inner guide 14. Thus, rotation of the first actuator 18 causes the first bearing 24 to rotate within the corresponding recess 30 to axially push the first bearing 24 within the inner slot 28. For example, when the recess is a helical recess, the bearing 24 is pushed along the helical groove path.

[0049] As will be described in detail below, the second actuator 22 rotates or translates the first actuator 18. The first actuator 18 includes a first recess 34 and a second bearing 26 is disposed within the first recess 34. Preferably, the first actuator 18 includes a pair of first recesses 34 that are diametrically opposed to each other. The first recesses 34 are generally hemispherical, with a radius approximately the same as the radius of the second bearing 26. The second bearing 26 is disposed in each first recess 34 and constrained within the length of a pair of pairs of slots 36 formed on the outer guide 20, thereby being diametrically opposed to each other.

[0050] The second actuator 22 is concentric with the outer guide member 20 and includes a second groove 38, such as Figure 3 As shown. The pitch of the second groove 38 is smaller than the pitch of the first groove 32. As used herein, the term "pitch" is the distance between the threads of the grooves 32, 38, measured along the length of the respective first and second actuators 22. It should be understood that the pitch can be designed to provide a specific travel rate and can be configured to provide a predetermined travel length relative to a predetermined rotation of the second actuator 22. Figure 3 As shown, the pitch "P2" of the second groove 38 is much smaller than the pitch "P1" of the first groove 32.

[0051] Figure 3The lengths of the inner slot 28 and the outer slot 36 are also depicted. The length of the inner slot 28 is longer than the length of the outer slot 36. The length of the second actuator 22 is approximately the same as the length of the inner slot 28. Preferably, the recess 30 is positioned from the front end of the bracket 16 so that when the first bearing 24 is translated to the distal end of the inner slot 28, the front end of the bracket 16 is positioned at the front end of the inner guide 14.

[0052] For reference Figure 4A and Figure 4B The description of the operation of mechanism 10 is provided. Mechanism 10 is designed to provide what is commonly referred to as coarse focus adjustment and fine focus adjustment, wherein in coarse focus adjustment, the lens travels at a much greater rate than in fine focus adjustment given the same amount of rotation of the second drive 22.

[0053] Generally, coarse focus adjustment is made when the second bearing 26 is moved to one end of the outer slot 36, i.e., end 36a or 36b. As an example, clockwise rotation of the second actuator 22 moves the second bearing 26 from end 36b to end 36a, wherein continuous clockwise rotation of the second actuator 22 causes the second bearing 26 to press against end 36a of the outer slot 36 and causes the first bearing 24 to slide along the inner slot 28 at a travel rate based on the pitch P1 of the first groove 32 of the first actuator 18. Fine focus adjustment occurs as the second bearing 26 travels within the inner slot 28. Therefore, coarse focus adjustment allows the user to move the lens generally past the focal point and then use fine focus adjustment to bring the lens back to the focal point. This feature saves the user time.

[0054] Figure 4B The position of the dual-speed focusing mechanism 10 is depicted, with the second bearing 26 located at the end of the outer slot 36. Specifically, the second bearing 26 presses against the distal end 36a of the outer slot 36. It should be understood that the dual-speed focusing mechanism 10 is configured to move the carriage 16 along the length of the outer slot 36 at a travel rate defined by the second groove 38 of the second actuator 22. Figure 4B The diagram depicts the second actuator 22 rotating in the direction indicated by the curved arrow. The rotation of the second actuator 22 causes the second bearing 26 to move in the direction indicated by the straight arrow.

[0055] For reference Figure 4AThe continued rotation of the second actuator 22 causes the second bearing 26 to push against the distal end 36a of the outer slot 36, thus causing the first bearing 24 to translate along the inner slot 28 in a clockwise direction as indicated by the arrow. Because the travel of the second bearing 26 is restricted, the second actuator 22 continues to rotate in the direction indicated by the curved arrow, and the first bearing 24 translates along the inner slot 28 at a travel rate determined by the pitch P1 of the first groove 32. In other words, the rotation of the second actuator 22 axially advances the second bearing 26 to either the distal end 36a or the proximal end 36b of the outer slot 36. Figure 4A As shown, continuous rotation in the same direction will actuate the first driver 18, where the travel rate is now set by the first groove 32. For illustrative purposes, we will assume that the user has already rotated the second driver at a coarse focus adjustment rate and passed the ideal focus image. Therefore, the user will need to move the lens unit 40 axially in the opposite direction to bring the image to the preferred focus. The mechanism 10 is configured to focus the image using fine focus adjustment after the lens unit 40 has moved past the focus.

[0056] Figures 5-7 One aspect of the mechanism 10 that performs fine focus adjustment is shown. First, refer to... Figure 5 The second bearing 26 is disposed on the distal end 36a of the outer slot 36. The second actuator 22 rotates counterclockwise, as indicated by the curved arrow. Since there is no structure restricting the advancement of the second bearing 26, the travel rate of the carriage 16 is determined by the engagement of the second bearing 26 within the second groove 38. Consequently, the travel rate of the carriage 16 from the distal end 36a to the proximal end 36b of the outer slot 36 is less than the travel rate of the first bearing 24 when it moves along the inner slot 28.

[0057] For reference Figure 6 The second bearing 26 is approximately located at the center of the outer slot 36. The second actuator 22 rotates counterclockwise, and the second bearing 26 moves freely from the distal end 36a to the proximal end 36b of the inner slot 28. During its travel along the inner slot 28, the travel rate of the bracket 16 is significantly less than the travel rate of the outer slot 36. Therefore, the user can make fine focus adjustments within the limits of the outer slot 36. That is, fine focus adjustments are made regardless of whether the second actuator 22 rotates clockwise or counterclockwise within the distal end 36a or proximal end 36b of the outer slot 36.

[0058] Figure 7 The illustration depicts a situation where the second bearings 24, 26 have reached the proximal end 36b of the outer slot 36. In this case, further clockwise rotation would force the bracket 16 to move along the inner slot 28, where the first bearing 24 engages in the first groove 32 and moves at a greater rate than the second bearing 26 moves within the outer slot 36.

[0059] It should be understood that the fine focus adjustment range can be based on the desired number of turns of the second actuator 22. In this configuration, the length of the outer slot 36 is sized to allow half a turn of the second actuator 22 to complete the travel length of the second bearing from the distal end 36a to the proximal end 36b of the outer slot 36. However, it should be understood that the lengths of the outer slot 36 and the inner slot 28 are provided for illustrative purposes and may deviate from the lengths shown without narrowing the scope of the appended claims. Similarly, the pitch provided for the first groove 32 and the second groove 38 may deviate from the shown base 12d based on the desired performance of the focusing mechanism 10.

[0060] In other aspects, mechanism 10 may further include a friction member 44 and a stop 46. The friction member 44 is configured to generate a rotational drag force to help prevent the inner guide 14 from rotating relative to the second actuator 22. In one aspect, the friction member 44 is shown as a washer commonly referred to as an O-ring. This aspect may be desirable to help keep the inner guide 14 stationary relative to the second actuator 22 during fine focus adjustment. In one aspect, the friction member 44 includes a first friction member 44a and a second friction member 44b disposed at opposite ends of the second actuator 22. The first friction member 44a is compressed between the inner surface of the second actuator 22 and the stop 46. The second friction member 44b is compressed between the inner surface of the second actuator 22 and the inner guide 14. The stop 46 is fixedly mounted to the end of the inner guide 14 to hold the second actuator 22 in the operating position. In one aspect, the inner surface of the stop 46 is welded to the outer surface of the end of the inner guide 14. The third friction member 44c may be disposed between the stop 46, the inner guide 14, and the outer guide 20. It should be understood that the first friction member 44a and the second friction member 44b may also be used to dampen the force generated by the first actuator 18 and the second actuator 22 against the base 12 and the stop 46. As described above, when the second bearing 26 reaches the ends 36a, 36b of the outer slot 36, the continuous rotation of the second actuator 22 drives the first actuator 18. Thus, when the first bearing 24 reaches the end of the inner slot 28, the first actuator 18 and the second actuator 22 are adjacent to and abut against the base 12 or the stop 46. Friction members 44a, 44b, and 44c may be formed of generally durable and elastic materials such as elastomers (e.g., nitrile rubber, silicone rubber, thermoplastic elastomers, or the like).

[0061] It should be understood that the coarse-focused travel rate is based on the pitch of the first groove 32. In one aspect, the coarse-focused travel rate can be adjusted to slow the second drive 22 in one or both directions before reaching the end of travel. This feature can be desirable to help dampen the load generated by the second drive impacting the base 12 or the stop 46.

[0062] For reference Figure 8 The first groove 32 is shown to have a variable pitch P1. Specifically, the pitch P1 is smaller at the end of the first groove 32 than at the center of the first groove 32. As a result, the speed of the second drive 22 is slowed down at the end of its travel relative to the center of the first drive 18. Figure 8 The first groove 32 is depicted with a center having a pitch "P1", and its ends having pitches "P1a" and "P1b", respectively. Pitch P1 is greater than pitches P1a and P1b. Preferably, pitches P1a and P1b are greater than the pitch P2 of the second groove 38. The first groove 32 can be configured to gradually transition from pitch P1 to pitches P1a and P1b to provide a smooth tactile response. Thus, the first actuator 18 and the second actuator 22 are slowed down before impacting the base 12 or the stop 46.

[0063] Although specific embodiments have been described and illustrated herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Furthermore, while various aspects of the claimed subject matter have been described herein, such aspects need not be used in combination. Therefore, the appended claims are intended to cover all such changes and modifications within the scope of the claimed subject matter.

Claims

1. A dual-speed mechanism configured to convert rotary motion into axial displacement at different rates, the dual-speed mechanism comprising: A base having an inner guide, the inner guide being a tubular member with an inner slot; A bracket disposed within the inner guide member, the outer surface of the bracket having an indentation; The first actuator is a tubular member concentric with the inner guide member. The inner surface of the first actuator has a first groove, which is helical and has a first pitch. The outer surface of the first actuator has a first recess. An outer guide member, which is a tubular member concentric with the first driver, has an outer slot; The second actuator is a tubular member concentric with the outer guide member, and the inner surface of the second actuator has a second groove, which is helical and has a second pitch smaller than the first pitch. A first bearing is disposed within the recess, the inner slot, and the first groove; A second bearing is disposed within the first recess, the outer slot, and the second groove; and The rotation of the second driver causes the bracket to translate axially at different rates.

2. The dual-speed mechanism according to claim 1, wherein the first pitch is at least twice the size of the second pitch.

3. The dual-speed mechanism according to claim 1 further includes a first washer defining the outer surface of the inner guide member.

4. The dual-speed mechanism according to claim 1, wherein the bracket includes a lens.

5. The dual-speed mechanism according to claim 1, wherein the inner guide comprises a pair of inner slots.

6. The dual-speed mechanism according to claim 1, wherein the outer slot is shorter than the inner slot.

7. The dual-speed mechanism of claim 1, wherein the first pitch is variable such that it is larger at the center of the first groove than at the end of the first groove.

8. A focusing mechanism for a camera, the focusing mechanism comprising: A base with an inner guide, the inner guide being a tubular member with an inner slot, a bracket disposed within the inner guide, the outer surface of the bracket having an indentation, the bracket holding a lens unit; The first actuator is a tubular member concentric with the inner guide member. The inner surface of the first actuator has a first groove, which is helical and has a first pitch. The outer surface of the first actuator has a first recess. An outer guide member, which is a tubular member concentric with the first driver, has an outer slot; and The second actuator is a tubular member concentric with the outer guide member. The inner surface of the second actuator has a second groove, which is helical and has a second pitch smaller than the first pitch. A first bearing is disposed within the recess, the inner slot, and the first groove, wherein the focusing mechanism is configured to convert the rotation of the first driver into axial movement of the lens unit within the inner slot; A second bearing is disposed within the first recess, the outer slot, and the second groove; and The rotation of the second driver causes the lens unit to translate axially at different rates within the inner guide and the outer guide.

9. The focusing mechanism of claim 8, wherein the first pitch is at least twice the size of the second pitch.

10. The focusing mechanism of claim 8, further comprising a first washer defining the outer surface of the inner guide member.

11. The focusing mechanism of claim 8, wherein the bracket includes a recess, and the lens unit is located within the recess.

12. The focusing mechanism of claim 8, wherein the inner guide comprises a pair of inner slots.

13. The focusing mechanism of claim 8, wherein the outer slot is shorter than the inner slot.

14. The focusing mechanism of claim 8, wherein the first pitch is variable such that it is larger at the center of the first groove than at the end of the first groove.

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