Feed mechanism and measuring device containing it

Abstract

A feed mechanism (200) operable to advance and move a slider (110) that is relatively movable along a longitudinally extending main scale (102) of the slider (110), the feed mechanism (200) comprising: a drive gear (220) which is or comprises a gear train to be pivotally carried or supported by the slider (110); a driven roller (230) configured to be directly or indirectly engaged with the drive gear (220) and to rotate by the rotation of the drive gear (220), the driven roller (230) being held substantially abutting against the main scale (102); an arm (240) pivotally supported by the slider (110) at a base end, the arm (240) including a cup-shaped portion (242) capable of at least partially receiving the driven roller (230) at a distal end; and a biasing unit (250) configured to bias the cup-shaped portion (242), which is in a state of receiving the driven roller (230), toward the main scale (102).

Description

The present invention relates to a pusher feed mechanism, such as a feed mechanism for raising and lowering a pusher of a altimeter along a column, and a measurement device including the same.A measuring device is already known which includes a slide movable along a column, such as a altimeter. The measuring device measures a size of a measurement object based on a movement amount of the slider (JP 4 377 156 B2). To move the slider, a rack (straight gear) is provided on a side surface of the column so that the slider is moved by engagement between the rack and a pinion pivotably supported on the slider.A good engagement between the rack and the pinion is essential for accurately moving the slider with good operability.However, in the case of a long rack (straight gear train) for covering a gauge length, machining difficulties arise when the gear teeth are accurately engaged, and increased costs are caused. Further, a tooth surface may be damaged when fine dust such as metal chips is caught between the rack and the pinion, and unstable positioning may occur.In this connection, a thumb wheel is known, which can be applied to a slide gauge, for example. Also, a feed mechanism is known in which an operator moves a slider along a main scale while pressing the thumb wheel with a thumb by rotating the thumb wheel (for example, see Patent Document 2: JP 2015-165 233 A). Thus, the above problem does not exist because no rack and pinion method is employed.However, it may prove difficult to rotate the thumb wheel while pressing it with the thumb because the slider of the altimeter is also heavy. Also, in view of usability, there is a problem in measurement efficiency when only the thumb wheel is used to cause movement from one end to the other end of a measurement stroke.This problem is not limited to altimeters only, but presents a general problem with respect to a measurement device that measures the size of an object to be measured based on a relative amount of movement between a main scale and a slider.An object of the invention is to provide a slide feed mechanism which is convenient in handling with a good durability and a low cost and which can dispense with the rack and pinion method.This problem is solved according to the invention by the features of the independent claims. Further embodiments of the invention are subject matter of the dependent claims.According to one aspect, there is provided a feed mechanism that feeds and moves a slide that is relatively movable along a main scale of the slide extending in a longitudinal direction, the feed mechanism comprising:a drive gear that is or comprises a gear train that is pivotally supported or to be supported by the slider;a driven roller configured to directly or indirectly engage the drive gear and rotate by rotation of the drive gear, the driven roller being held substantially abutting the main scale;an arm pivotally supported by the slider at a base end, the arm comprising a cup-shaped portion capable of receiving the driven roller at least partially at a distal end; anda biasing unit configured to bias the cup-shaped portion in a state of receiving the driven roller toward the main scale.According to an embodiment of the invention, the driven roller preferably comprises:a driven gear that is or comprises a gear train that directly or indirectly engages the drive gear;a clamping disk provided coaxially with the driven gear, the clamping disk being paired with the driven gear to clamp the main scale; anda clutch shaft configured to coaxially couple the driven gear and the clamp plate.In particular, a diameter of the clamping disk is preferably smaller than a diameter of the driven gearwheel.Further, in particular, the arm is preferably pivotally supported such that it is coaxial with a rotation axis of the drive gear.Further, more specifically, a distance between a center of a shaft hole of the arm and a center of the cup-shaped portion is equal to a sum of a radius of the drive gear and the radius of the driven gear.Furthermore, the pretensioning unit comprises in particular a pin-shaped locking bolt and a pin at a distal end and has an integrated spring.According to another aspect, there is provided a measurement device including the above-described feed mechanism.Brief Description of the DrawingsThese and other objects, features and advantages of the present invention will become more apparent upon consideration of the following detailed description of preferred embodiments and the drawings. It should be noted that, despite the separate description of the embodiments, individual features can be combined therefrom to form additional embodiments. FIG. 1 is an enlarged view of a slider in a front view of a altimeter. FIG. 2 is an exploded perspective view of a feed mechanism. FIG. 3 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 4 is an enlarged view of a main part of the feed mechanism. FIG. 5 is a view illustrating a case where a side surface of a pillar is slightly wave-shaped. FIG. 6 is a view showing an example in which the feed mechanism is applied to a depth gauge. FIG. 7 is an enlarged view of the feed mechanism.DESCRIPTION OF THE EMBODIMENTSHereinafter, an embodiment of the invention will be described with reference to the drawings and the reference numerals assigned to the elements illustrated in the drawings.First EmbodimentA first specific embodiment will be described below. The first specific embodiment is described with reference to Figs. 1 to 5.FIG. 1 is an enlarged view of a slider 110 in a front view of a altimeter 100 described in the present embodiment.FIG. 2 is an exploded perspective view for the purpose of facilitating understanding of a configuration of a feed mechanism 200.The altimeter 100 (as a specific measuring device) includes a base 101, a column 102 serving as a main scale in particular and erected on or protruding from the base 101, a slider 110 substantially movable along the column 102 (in particular, upward and downward), and a feed mechanism 200 that moves the slider 110.The column 102 is made of a metal, for example, and / or has a rectangular cross section.In the present embodiment, a side surface 103 of the column 102 is substantially made to be as straight and flat as possible to take the role of a reference guide surface of the movement of the slider. Note that in the present embodiment, no rack conventionally provided on the side surface 103 of the column 102 is required.The slide 110 has in particular a substantially U-shaped cross section and / or is fastened to the column 102 in such a way that the column 102 is at least partially held in its interior.In FIGS. 1 and 2, the slider 110 is fixed to the pillar 102 from a rear surface side of the pillar 102. On a front surface side of the column 102, horizontal beams 111 span the slider 110 and are screwed to an upper end and a lower end of the slider 110, respectively. Accordingly, the slider 110 is slidable in a longitudinal direction of the column 102 (in particular, in a vertical direction along the column 102) without being detached from the column 102.Hereinafter, in order to facilitate easy understanding of the descriptions, the left side in FIGS. 1 and 2 is referred to as the "front side" of the altimeter 100, while the right side is referred to as the "rear side" of the altimeter 100.The slider 110 is provided with a leg 112 protruding at a lower end of a front side thereof. A scribing needle 114 is attached to the leg 112 via a fastening unit 113.Even if not illustrated, an electric unit (specifically, including a digital display unit, a code ruler detection head, and the like) is fixed to the slider 110 (specifically, at a front side thereof).On a rear side of the slider 110, a feed mechanism fixing unit 120 for fixing the feed mechanism 200 is provided. Although the feed mechanism 200 is provided to the feed mechanism attachment unit 120, a structure of the feed mechanism attachment unit 120 will be described below in connection with a configuration of the feed mechanism 200.The feed mechanism 200 includes a handle 210, a drive gear 220, a driven roller 230, an arm, and / or a pin-shaped latch bolt 250.The handle 210 has, in particular, a short cylindrical shape having a radius such that it is exactly adapted to be held by the hand of an operator, on a side surface of which knurls 211 are provided.The drive gear 220 is or includes a so-called gear train and is screwed to a rear side of the handle 210 to be coaxial therewith. That is, the handle 210 and the drive gear 220 integrally rotate.The driven roller 230 includes a driven gear 231, a clamping plate 232 coaxial with the driven gear 231, the clamping plate 232 being paired with the driven gear 231 to clamp a side surface of the column 102 and / or a clutch shaft 233, the driven gear 231 and the clamping plate 232 being coaxially coupled.The driven roller 230 seems to have a substantially H-shape, in particular, provided in a plane passing through the center of the clutch shaft 233.FIG. 3 is a cross-sectional view taken along line II-II in FIG. 1 ; in FIG. 3, the driven roller 230 has a substantially H-shaped cross section, in particular.However, the surfaces of the driven gear 231 and the clamping plate 232 that are substantially opposed to each other are slightly chamfered, so that a distance between the driven gear 231 and the clamping plate 232 separated from the clutch shaft 233 slightly increases.The driven gear 231 is or includes a gear train and is formed to have teeth on an outer surface so as to be properly engaged with the teeth of the drive gear 220. The clamping disk 232 merely needs to be flat and does not have any teeth on its outer surface.A radius of the clamping disk 232 is slightly smaller than a radius of the driven gear 231.A certain size is required for the radius of the driven gear 231 because it is necessary to provide teeth on the driven gear 231.Meanwhile, the clamping disk 232 only needs to have such a radius as to clamp the side surface 103 of the column 102 by being paired with the driven gear 231, in particular, and it is not necessary to provide a clearance (trim allowance) for teeth and the like in manufacturing.The case where teeth are cut into the driven gear 231 after the driven roller 230 is integrally molded offers an advantage that the teeth are easily formed only on the driven gear 231 without the clamping disk 232 interfering with strokes of a blade (gap) because the driven roller 231 and the clamping disk 232 have different radii. The driven roller 230 may be formed by compression molding at a high density. In this case, with a small clamping disk 232, the material costs are reduced.The clutch shaft 233 coaxially couples the driven gear 231 and the clamping plate 232.The coupling shaft 233 is in particular hollow in the cross-sectional view of FIG. 3, but it can also be made solid.Specifically, as shown in FIG. 3, the clutch shaft 233 only needs to have such a length that the slope of the driven gear 231 and / or the clamping plate defined by the opposed surfaces contacts and clamps the column 102 when the driven roller 230 is pressed against the side surface of the column 102.Specifically, the arm 240 is a flat rod substantially in its entirety, and includes a shaft hole 241 at a base end and a cup-shaped half-tube-like portion 242 at a front end.FIG. 4 is an enlarged view of a main part of the feed mechanism 200.A distance L between a center of the shaft hole 241 of the arm 240 and the center of the cup-shaped portion 242 is equal to a sum of a radius of the drive gear 220 and the radius of the driven gear 231.An axis of the shaft hole 241 is parallel to an axis of the cup-shaped portion 242. A direction in which the cup-shaped portion 242 is opened in the cup-shaped portion 242 is substantially perpendicular to a longitudinal direction of the arm 240. The cup-shaped portion 242 is capable of receiving the clutch shaft 233 of the driven roller 230.The pin shaped locking bolt 250 (as a particular biasing unit) comprises in particular a pin 251 at an upper end with an integrated spring (not shown). The pin-shaped latch bolt 250 is rigidly fixed to a hole in the side surface of the slider 110, and biases the cup-shaped portion 242 toward the column 102 to push the cup-shaped portion 242 from back to front.Next, a specific assembling method of the feed mechanism 200 and the configuration of the feed mechanism fixing unit 120 will be described.First, a U-shaped recess 121 is formed in a surface on a rear side of the slider 110 opposite to the side surface 103 on a rear side of the pillar 102. The recess 121 is referred to as the driven roller receiving recess 121 because it is used to at least partially receive the driven roller 230.The driven roller 230 is held in a gap between the side surface 103 of the column 102 and the driven roller receiving recess 121.(Details are described below)At this time, the clamping disk 232 reaches the front surface of the slider 110 while the driven gear 231 reaches the rear surface side of the slider 110.Next, a recess 122 is formed in a rear surface on the rear side of the slider 110, which is cut out from the rear surface toward the front surface. The recess 122 is referred to as the drive gear receiving recess 122, because the arm 240 and the drive gear 220 are received in the recess 122.A hole is provided in the slider 110 adjacent to (in particular, slightly below) the driven roller receiving recess(s) 121. A shaft core 260 penetrates the hole at least partially from the front surface side to the rear surface side of the slider 110.The shaft core 260 penetrates the shaft hole 241 of the arm 240, the drive gear 220, and the handle 210 one by one from the front surface side, and is fixed from one side of the handle 210, for example, by being fastened by a lock pin 261. In this way, the shaft hole 241 of the arm 240, the drive gear 220, and the handle 210 cannot be detached from each other. Accordingly, the shaft core 260 serves as the tilt center shaft of the arm 240, a rotation center of the drive gear 220, and a rotation center of the handle 210.In addition, the coupling shaft 233 of the driven roller 230 may first enter the cup-shaped portion 242 of the arm 240 so that the driven roller 230 enters the driven roller receiving recess 121 when the arm 240 is fastened.Finally, the pin-shaped locking bolt 250 is fastened to the slide 110 from behind, so that the pin 251 of the pin-shaped locking bolt 250 protrudes from the cup-shaped section 242 of the arm 240 from the rear side forwards.When the feed mechanism 200 is thus attached to the feed mechanism attachment unit 120 of the slider 110, the driven roller 230 abuts on the side surface 103 of the column 102 in a state of being at least partially accommodated in the cup-shaped portion 242 of the arm 240. The driven roller 230 is pressed against the side surface 103 of the column 102 in a state of being at least partially accommodated in the cup-shaped portion 242 of the arm 240 while the cup-shaped portion 242 is pressed by the pin-shaped lock bolt 250. Further, the drive gear 220 engages with the driven gear 231 of the driven roller 230.It is assumed that an operator of the altimeter 100 operates (for example, rotates) the handle 210 to adjust the height of the slider 110.Although the operator operates the handle 210 from a rear surface side of the altimeter 100 and rotates the handle 210 rightward, an arrow A appears to face leftward in the drawings because the altimeter 100 is shown viewed from the front in FIGS. 1, 2, and 4.The drive gear 220 rotates integrally with the handle 210 (see arrow A in FIG. 4 ).Then, the driven gear 231 engaged with the drive gear 220 rotates (arrow B), and the driven roller 230 rotates accordingly.Since the driven roller 230 is pressed against the side surface 103 of the column 102, the slider 110 can move substantially along the column 102 (arrow C) together with the feed mechanism 200 when the driven roller 230 rotates in a state of clamping the side surface 103 of the column 102 without sliding. In the present example, the slider 110 is lowered.In order to understand the operation of the feed mechanism 200 described in the present embodiment, an example shown slightly exaggeratedly is to be seen in FIG. 5. In FIG. 5, it is assumed that the side surface 103 of the pillar 102 is not straight but is a little wave-shaped.Even in this case, the driven roller 230 of the feed mechanism 200 described in the present embodiment follows the side surface 103 of the shaft-shaped column 102, and the driven roller 230 rotates in a state of clamping the side surface 103 of the column 102 without sliding. A shaft (coupling shaft 233) of the driven roller 230 is not fixed to the slider 110, but is held in a state of being at least partially accommodated by the cup-shaped portion 242 of the pivotable arm 240.The driven roller 230 is pressed substantially at all times or continuously against the side surface 103 of the column 102, changing its position together with the pivoting arm 240 while the cup-shaped portion 242 of the arm 240 is pushed by the pin-shaped latch bolt 250.In FIG. 5, the arm 240 is pivoted to the left (arrow D) compared to a state shown in FIG. 4, and the pin 251 of the pin-shaped locking bolt 250 protrudes further than the pin shown in FIG. 4.In this way, the driven roller 230 rotates without sliding in a state of sandwiching the side surface 103 of the column regardless of how wavy the side surface 103 of the column 102 is.Further, the driven gear 231 and the drive gear 220 are held in a matching engagement even when the driven roller 230 changes position depending on the wave shape of the side surface 103 of the column 102.Specifically, a distance L between the center of the shaft hole 241 of the arm 240 and the center of the cup-shaped portion 242 is equal to a sum of a radius of the drive gear 220 and the radius of the driven gear 231. Thereby, the distance between the driven gear 231 and the drive gear 220 remains constant even when the arm 240 is pivoted around the shaft hole 241.The driven gear 231 and the drive gear 220 are held in a mating engagement while the driven roller 230 is held by the cup-shaped portion 242. Accordingly, the operability is favorably maintained during the feeding operation of the slider 110 even when the surface treatment of the side surface 103 of the column 102 is slightly inferior.In this way, a rack is unnecessary particularly when the feed mechanism 200 described in the present embodiment is used. Since it is not necessary to prepare a long rack (gear train) covering a gauge length, the problems caused by the rack, such as high manufacturing cost and damage to the tooth surfaces, are all avoided. Further, since the rack is unnecessary, it is also easy to achieve a longer stroke of the altimeter 100.Modified Example 1Some modified examples of the first specific embodiment are additionally explained below.In the above-described embodiment, the drive gear 220 and the driven gear 231 of the driven roller 230 are in direct mesh with each other. However, a different series of gear trains may be arranged between the drive gear 220 and the driven gear 231.In the above-explained embodiment, the pin-shaped locking bolt 250 is described as an example as a biasing unit for pressing the cup-shaped portion 242 toward the side surface 103 of the pillar 102. However, the invention is not limited to the pin-shaped lock bolt 250, and it is possible to provide another member capable of exerting a biasing force, such as a leaf spring, a coil spring, and an elastic rubber.Further, although the cup-shaped portion 242 is pushed from behind, the same effect can be obtained when a biasing force is applied to pull the cup-shaped portion 242 toward the supporting column 102.In the above-described embodiment, the shaft core 260 is at least partially inserted into the shaft hole 241 of the arm 240 such that the inclination center of the arm 240 and the rotation center of the drive gear 220 coincide with each otherHowever, in this configuration, although it is preferable that an engagement depth between the driven gear 231 and the drive gear 220 does not change at all, it poses no problem when the distance between the driven gear 231 and the drive gear 220 changes slightly as long as the engagement does not cancel. Therefore, the inclination center of the arm 240 may be displaced from the rotation center of the drive gear 220, and the base end of the arm 240 may be pivotally supported at any position in the slider 110.Second EmbodimentA second specific embodiment will be described below. A basic configuration described in the second specific embodiment is identical to the basic configuration described in the first embodiment and is an example suitable for applying a feed mechanism to a smaller measurement device.FIG. 6 illustrates an example of a depth gauge 300. Even if the depth measuring device is shown here, a so-called measuring slide can also be used.The depth gauge 300 allows a main scale 320 to be advanced and moved relative to a detection head 310.The feed mechanism 200 is to be attached to a rear end of the detection head 310.FIG. 7 illustrates an enlarged view of the feed mechanism 200. The feed mechanism described in the second embodiment is basically the same as the feed mechanism described in the first embodiment. Therefore, corresponding elements are denoted by the same reference numerals, and the description of these elements will not be repeated.In the first embodiment, the pin-shaped lock bolt 250 may be directly fixed to the driven roller 230 from behind, while the surface of the slider 110 opposite to the side surface 103 of the pillar 102 has a depression in a U-shape to form the driven roller receiving recess 121.However, in this configuration, a member such as the slider 110 is necessary in the rear portion of the driven roller 230, which may result in the feed mechanism 200 having a slightly larger size.In view of this, in the second embodiment, a driven roller receiving recess 421 of the slider 110 is cut out from a side that is away from the main scale 320 toward the main scale, so that no link is present in the area behind the driven roller 230.In such a case, a push plate 243 extends from a front end of the arm 240 so that the arm 240 is slightly extended. Then, the pin-shaped lock bolt 250 need only be fixed to the slider 110 so as to press the thus-extending push plate 243.This makes it possible to further reduce the size of the feed mechanism 200.Accordingly, there is provided a slide feed mechanism which is convenient in handling with a good durability and a low cost and which can dispense with a rack and pinion method. The advancing mechanism allows the slide to be advanced and moved along a longitudinally extending main scale. The feed mechanism includes: a drive gear that is a gear train pivotably supported by the slider; a driven roller that engages with the drive gear and rotates by the rotation of the drive gear; and an arm that includes a cup-shaped portion capable of receiving the driven roller at a distal end. The arm includes the cup-shaped portion capable of receiving the driven roller at the distal end and is pivotally supported by the slider at a base end. The cup-shaped portion is biased toward the main scale by a pin-shaped lock bolt in a state of receiving the driven roller. Accordingly, the driven roller is caused to remain abutting on the main scale.The invention is not limited to the embodiment described above, and corresponding variants thereof are possible without departing from the basic idea of the invention.The force for rotating the drive gear may also be a non-manual force for rotating the handle, and a rotational force using a motor is also conceivable.List of reference characters100 Altimeter 101 Base 102 Column 103 Side surface of column 110 Slider 111 Beam 112 Leg 113 Fixing unit 114 Scribe needle 120 Feed mechanism fixing unit 121 Driven roller receiving recess 122 Drive gear receiving recess 200 Feed mechanism 210 Handle 211 Knurl 220 Drive gear 230 Driven roller 231 Driven gear 232 Clamping disk 233 Coupling shaft 240 Arm 241 Shaft hole 242 Cup-shaped portion 243 Thrust plate 250 Pin-shaped locking bolt 251 Pin 260 Shaft core 261 Locking pin 300 Depth gauge 310 Detection head 320 Main scale 421 Driven roller receiving recess

Claims

A feed mechanism (200) operable to feed and move a slider (110) relatively movable along a longitudinally extending main scale (102) of the slider (110), the feed mechanism (200) comprising: a drive gear (220) being or comprising a gear train to be pivotally supported by the slider (110); a driven roller (230) configured to directly or indirectly engage the drive gear (220) and rotate by the rotation of the drive gear (220), the driven roller (230) being held substantially abutting the main scale (102); an arm (240) to be swingably supported by the slider (110) at a base end, the arm (240) comprising a cup-shaped portion (242) capable of receiving the driven roller (230) at least partially at a distal end; and a biasing unit (250) configured to bias the cup-shaped portion (242) in a state of receiving the driven roller (230) toward the main scale (102).The feed mechanism (200) according to claim 1, wherein the driven roller (230) includes: a driven gear (231) that is or comprises a gear train directly or indirectly engaged with the drive gear (220); a clamping plate (232) provided coaxially with the driven gear (231), the clamping plate (232) being paired with the driven gear (231) to clamp the main scale (102); and a clutch shaft (233) configured to coaxially couple the driven gear (231) and the clamping plate (232).The advancement mechanism (200) of claim 2, wherein the clamping disc (232) has a radius less than a radius of the driven gear (231).The feed mechanism (200) according to any one of the preceding claims, wherein the arm (240) is pivotally supported so as to be coaxial with a rotation axis of the drive gear (220).The feed mechanism (200) according to any one of the preceding claims 2 to 4, wherein a distance (L) between a center of a shaft hole (241) of the arm (240) and a center of the cup-shaped portion (242) is equal to a sum of a radius of the drive gear (220) and the radius of the driven gear (231).The advancement mechanism (200) according to any one of the preceding claims, wherein the biasing unit (250) comprises a pin-shaped locking bolt (250) and a pin (251) at a distal end and has an integrated spring.A measuring device (100; 300) comprising the advancing mechanism (200) according to any one of the preceding claims.

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