BACKGROUND
The present application relates to hand tools and in particular to a chalk reel or chalk line device.
Conventional chalk reels include a housing, a spool positioned within the housing, and a chalk line wrapped onto the spool. A chalk material is also positioned in the housing to coat the chalk line. A hook is secured to an end of the chalk line, and another end of the chalk line is secured to the spool. The spool is rotatable about an axis and the spool may be manually rotated by operation of a crank or lever. A user may extract the line from the housing, position the line against a work surface, and snap the line in order to create a clear chalk line on the work surface.
SUMMARY
In one embodiment, a chalk line device includes a housing, a spool, a chalk line, a hook, and a cap. The housing defines an outer surface and an internal chamber, and the housing includes an opening. The spool is supported in the internal chamber for rotation relative to the housing. The chalk line extends through the opening of the housing and the chalk line includes a first end and a second end. At least a portion of the chalk line is wrapped around the spool. The hook is secured to the first end of the chalk line and includes a tip adapted to engage a work piece. The cap is removably coupled to the housing to cover the opening. The cap includes a nozzle through which the chalk line extends and a projection for engaging and releasably securing the hook against the cap.
In another embodiment, a chalk line device includes a housing, a spool, a chalk line, a drive mechanism for rotating the spool, and a clutch mechanism. The housing defines an outer surface and an internal chamber, and the housing includes an opening. The spool is supported in the internal chamber for rotation relative to the housing about a spool axis. The chalk line extends through the opening of the housing, and at least a portion of the chalk line is wrapped around the spool. The drive mechanism includes a lever and a gear member. The gear member is directly coupled to the spool at a spool interface. The lever is positioned proximate the outer surface and supported for rotation relative to the housing. Rotation of the lever transmits a torque to the gear member, which in turn transmits a torque to the spool to rotate the spool. The clutch mechanism selectively uncouples the gear from the spool at the spool interface when a torque transmitted by the gear member to the spool exceeds a predetermined threshold.
In yet another embodiment, the chalk line device includes a housing, a lever supported for rotation relative to the housing, a chalk line, and a spool. The housing defines an outer surface and an internal chamber, and the housing includes an opening. The chalk line extends through the opening of the housing such that an end of the chalk line is positioned outside of the internal chamber and a portion of the chalk line is supported in the internal chamber. The spool is supported in the internal chamber for rotation relative to the housing about a spool axis, and the spool is driven by rotation of the lever. The spool includes a pair of side walls and a hub extending between the pair of side walls. The hub extends around the spool axis, and the portion of the chalk line is wrapped around the hub. At least one of the side walls includes an inner portion, a peripheral portion, and a plurality of support members extending between the inner portion and the peripheral portion. Each support member is oriented parallel to and offset from a radial line that extends outwardly from the spool axis toward the peripheral portion. The plurality of support members define a plurality of openings positioned between each of the support members and extending through the side wall to permit chalk to pass through the side wall.
Other independent aspects will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a chalk line device.
FIG. 2 is an exploded view of a portion of the chalk line device of FIG. 1.
FIG. 3 is a perspective view of a cap for a chalk line device.
FIG. 4 is a side view of a portion of the chalk line device.
FIG. 5 is a section view of the chalk line device of FIG. 1 viewed along section 5-5.
FIG. 6 is a perspective view of a spool.
FIG. 7A is a side view of the spool of FIG. 6.
FIG. 7B is a front view of the spool of FIG. 6.
FIG. 7C is a reverse side view of the spool of FIG. 6.
FIG. 8 is an exploded view of the chalk line device of FIG. 1.
FIG. 9 is an exploded view of a drive mechanism.
FIG. 10 is a section view of the chalk line device of FIG. 1 viewed along section 10-10.
FIG. 11 is a perspective view of a lever, a gear member, and a spool.
FIG. 12 is a perspective view of the chalk line device of FIG. 1 with a cover removed.
FIG. 13 is a perspective view of a chalk line device according to another embodiment.
Before any embodiments are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
DETAILED DESCRIPTION
FIG. 1 illustrates a chalk reel or chalk line device 10 including a housing 14, a chalk line 18, a lever 22, a hook 26 secured to one end of the chalk line 18, and a cap 30 secured to the housing 14. In one embodiment, the housing 14 is formed from die cast aluminum; in another embodiment (FIG. 13), the housing 14 is formed from a plastic base overmolded with rubber or plastic.
The chalk line 18 may be constructed of Dacron®, or it may be a polyester blend (e.g., polyester nylon). In some embodiments, the chalk line 18 is formed by braiding sixteen strands and has between approximately 26 and approximately 34 picks per inch. As used herein, a “pick” refers to a linear or axial distance between two adjacent strand crossings. In some embodiments, the chalk line 18 has a diameter between approximately 1.05 mm and approximately 1.15 mm, and has a minimum tensile strength of 40 lbf. In some embodiments, the chalk line 18 has 30 picks per inch and a diameter of approximately 1.1 mm, providing a tensile strength of 49.6 lbf.
The lever 22 is supported for rotation on one side of the housing 14. One end of the lever 22 is coupled to an end of a post 34 that is coupled to the housing 14. The lever 22 is pivotable about the end of the post 34 between an open position and a stowed position (illustrated in FIG. 1). Another end of the lever 22 includes a handle 38 to be gripped by a user when rotating the lever 22. In the illustrated embodiment, the housing 14 includes a recess 42, and the handle 38 is positioned in the recess 42 when the lever 22 is in the stowed position.
Referring to FIG. 2, the hook 26 includes a first end secured to an end of the chalk line 18 and a second end including a tip or gripping edge 44. The gripping edge 44 engages a work piece (not shown) while the chalk line 18 is snapped by a user to impart a chalk mark. The hook 26 also includes a slot 46 positioned between the end of the chalk line 18 and the gripping edge 44.
The cap 30 includes a nozzle 50 extending through the cap 30, and the chalk line 18 passes through the nozzle 50. One end of the chalk line 18 is secured to the hook 26, and a portion of the chalk line 18 is positioned in the housing 14 as described in further detail below. The chalk line 18 can be drawn out of the housing 14 by applying a force on the hook 26, and the chalk line 18 can be reeled in or retracted into the housing 14 by rotating the lever 22 (FIG. 1).
FIGS. 2 and 3 illustrate the cap 30 and a portion of the housing 14, which includes an opening 54. The cap 30 includes a first end 52 (FIG. 3) and a second end 56 and defines a cap axis 62 (FIG. 3) extending between the first end 52 and the second end 56. A shank portion 58 is positioned proximate the first end 52 and is removably received within the opening 54. The shank portion 58 includes a partial thread 66. The shank portion 58 is inserted into the opening 54 and the cap 30 is rotated about the cap axis 62 until the partial thread 66 engages a circumferential protrusion 70 formed on the housing 14 and extending around the opening 54. In the illustrated embodiment, the cap axis 62 is aligned with the nozzle 50. In one embodiment, the cap 30 is rotated through an angle less than 360 degrees about the cap axis 62 to secure the cap 30 to the housing 14. In another embodiment, the cap 30 is rotated through an angle less than 180 degrees about the cap axis 62 to secure the cap 30 to the housing 14. In one embodiment, the cap 30 is rotated through an angle of approximately 90 degrees about the cap axis 62 to secure the cap 30 to the housing 14.
Referring to FIG. 2, a flange 72 is positioned between the first end 52 and the second end 56 of the cap 30 and separates the shank portion 58 from a second or outer portion 74 from the shank portion 58. Stated another way, the flange 72 is oriented perpendicular to the cap axis 62 (FIG. 3). The outer portion 74 includes a central shaft 78 extending partially along the cap axis 62 away from the flange 72. Ridges 82 extend from an upper end of the central shaft 78 toward an outer edge of the flange 72. In the illustrated embodiment, each ridge 82 is inclined downwardly toward the outer edge of the flange 72, and each ridge 82 is tapered such that a portion of each ridge 82 proximate the cap axis 62 is narrower than a portion proximate the outer edge of the flange 72. In the illustrated embodiment, the cap 30 includes four ridges 82 spaced apart from one another at equal angular intervals (i.e., 90 degrees about the cap axis 62).
An annular seal 90 is positioned between the flange 72 and the housing 14 to prevent chalk from leaking out of the housing 14. In the illustrated embodiment, two of the ridges 82 are positioned on diametrically opposite sides of the cap 30 and include ends 92 protruding below the flange 72. The seal 90 is positioned between the ends 92, and the ends 92 retain and align the seal 90 relative to the cap 30. A filter or cleaning element 94 is positioned in the shank portion 58 (FIG. 5) and wraps around the chalk line 18. As the chalk line 18 is retracted into the housing 14, the cleaning element 94 traps dirt or other impurities from being pulled into the housing 14 with the chalk line 18. In addition, an internal surface of the cap 30 may include a frustoconical formation 96 (FIG. 5) adjacent the cleaning element 94, such that when the chalk line 18 is extracted from the housing 14, the frustoconical formation 96 engages the cleaning element 94 and urges it away from the nozzle 50. A clip 98 is inserted into the shank portion 58 to secure the cleaning element 94 within the shank portion 58. In the illustrated embodiment, the clip 98 is inserted laterally into the shank portion 58, in a direction perpendicular to the cap axis 62.
In some embodiments, the cleaning element 94 has an outer diameter between approximately 8.2 mm and approximately 8.8 mm, and a length between approximately 11.7 mm and approximately 12.3 mm. In some embodiments, the cleaning element 94 has a nominal density of between approximately 3.1 g/cc and approximately 3.5 g/cc. In some embodiments, the cleaning element 94 has a nominal density of approximately 3.3. g/cc. The cleaning element 94 may be formed from wool felt and may have a material grade of F5. The characteristics of the cleaning element 94 provides a balance by allowing the chalk line 18 to pass through easily without resulting in high stress on the chalk line 18, while still being sufficiently tight to prevent spillage of the chalk contained within the housing 14.
As shown in FIGS. 1 and 4, the cap 30 includes a mechanism for securing the hook 26 relative to the cap 30. In the illustrated embodiment, one of the ridges 82 forms a projection 102 extending radially beyond the outer edge of the flange 72. The projection 102 has a more shallow slope or taper than the other ridges 82. The projection 102 is positioned in the slot 46 (FIG. 1) and engages an edge of the slot 46 to secure the hook 26 against movement. Stated another way, the hook 26 is aligned along the ridge forming the projection 102 such that the projection 102 extends through the slot 46. In other embodiments, the projection 102 may be received within a gap or space 100 (FIGS. 1 and 2) between portions of the gripping edge 44. In still other embodiments, multiple ridges 82 may include projections extending beyond the outer edge of the flange 72. Securing the hook 26 against the cap 30 provides a compact storage configuration to insure that the hook 26 does not snag on clothing or other items. Furthermore, by engaging the cap 30 instead of the housing 14, less chalk line is extracted from the housing 14 and exposed during storage.
As shown in FIG. 5, the housing 14 defines a chalk chamber or internal chamber 104 supporting a spool 106. The spool 106 is rotatable relative to the housing 14 about a spool axis 110. The chalk line 18 is wrapped onto the spool 106 while the chalk line 18 is stored, and the line 18 may be unwrapped from the spool 106 by applying a force on the chalk line 18. The internal chamber 104 contains a chalk material (not shown) that coats the chalk line 18 positioned in the internal chamber 104. In the illustrated embodiment, the housing 14 supports a guide tube 114 through which the chalk line 18 passes between the spool 106 and the cap 30. The guide tube 114 defines the path of the chalk line 18 and insures that the chalk line 18 does not rub on any internal surfaces of the housing 14, thereby reducing wear on the chalk line 18.
As shown in FIGS. 6 and 7A, the spool 106 includes a first side wall 130a, a second side wall 130b, and a hub 134 extending between the side walls 130. As shown in FIG. 7B, in the illustrated embodiment, the hub 134 is generally cylindrical, and a portion of the hub 134 proximate one side wall 130 has a frustoconical shape. The chalk line 18 (FIG. 5) is wrapped around the hub 134. Referring to FIG. 7A, each side wall 130 includes an inner portion 142 positioned adjacent the hub 134 and a peripheral portion 146 positioned radially outward of the inner portion 142. In addition, support members 150 extend between the inner portion 142 and the peripheral portion 146. In the illustrated embodiment, the support members 150 are arranged in groups at 90 degree intervals around the spool axis 110. Each support member 150 is oriented parallel to and offset from a radial line that extends outwardly from the spool axis 110 toward the peripheral portion 146.
For purposes of illustration, a first radial reference line 154 is illustrated in FIG. 7A and extends outwardly from the spool axis 110. A pair of parallel support members 150a are offset from either side of the first radial reference line 154. A pair of support members 150b are positioned 180 degrees apart from the support members 150a and positioned in a similar manner. A second radial reference line 158 extends from the spool axis 110 at 90 degrees to the first reference line 154. Three support members 150c are oriented parallel to the second reference line 158, with one of the support members 150c aligned with the second reference line 158 and the other two support members 150c are positioned on either side and offset from the second reference line 158. A group of support members 150d are positioned 180 degrees apart from the support members 150c and are positioned in a similar manner. In the illustrated embodiment, each of the four groups of support members 150a, 150b, 150c, 150d are spaced apart from one another at 90 degree angular intervals about the spool axis 110.
Openings 162 are defined between the support members 150 and extend through each side wall 130. A group of first openings 162a are positioned in an angular region between each adjacent group of support members 150, such that the first openings 162a form a generally triangular shape. A group of second openings 162b are positioned between each of the support members 150 in each group. The openings 162 permit chalk in the internal chamber 104 to pass through the side walls 130, thereby penetrating the space between the side walls 130 and more thoroughly coating the chalk line 18 wrapped on the spool 106.
Although the support members 150 and openings 162 have been described in detail with respect to the first side wall 130a, it is understood that the second side wall 130b includes similar support members 150 and openings 162. In other embodiments, the support members 150 and openings 162 may be formed in a different manner. In other embodiments, the support members 150 and openings 162 of each side wall 130 may not be identical, and/or may not be aligned with one another.
As shown in FIG. 7A, the spool 106 includes a clutch surface 170 positioned on a first side wall 130a, and the clutch surface 170 includes driven clutch teeth 174. In the illustrated embodiment, the clutch surface 170 is concentric with the spool axis 110 and includes three driven clutch teeth 174 positioned at equal angular intervals around the spool axis 110. As shown in FIGS. 7B and 7C, the second side wall 130b is positioned on the hub 134 opposite the clutch surface 170, and the second side wall 130b includes an opening 178 (FIG. 7C). In one embodiment, the first side wall 130a and second side wall 130 may have different diameters, such that one side wall is smaller than the other.
As shown in FIG. 8, in the illustrated embodiment the housing 14 is formed as two portions 14a, 14b coupled together. An inner surface of portion 14b includes a support post 118, and the support post 118 is received in the opening 178 of the second side wall 130b to support the spool 106 for rotation about the spool axis 110. The portion 14a includes an extended wall portion 180 protruding beyond the edge of the housing portion 14a. The extended wall portion extends substantially around the perimeter of the housing portion 14a and is received in a recess 184 formed on an inner surface of the portion 14b when the housing portions 14a, 14b are assembled together. In one embodiment, the extended wall portion 180 protrudes 4.6 mm beyond the edge of the housing portion 14a. In the illustrated embodiment, the portions 14a, 14b are coupled together by a pair of retention screws 122. Each screw 122 may be unthreaded from the portion 14a to release the portion 14a, yet remain coupled to the portion 14b by a washer 128 (FIG. 10) secured to the portion 14b.
Referring now to FIGS. 9 and 10, the lever 22 is drivingly connected to the spool 106 (FIG. 10) by a drive mechanism 182. The drive mechanism 182 transmits torque applied on the lever 22 by a user to rotate the spool 106 and wind in the chalk line 18. The drive mechanism 182 includes a planetary gear drive including a ring gear 186, planet gears 190, and a sun gear 194. The ring gear 186 includes internal teeth 198 and a hole 202 for receiving an end of the post 34 supporting the lever 22. In the illustrated embodiment, the end of the post 34 includes a spur gear 204 having teeth that mesh with complementary teeth extending around the hole 202 on the ring gear 186. The ring gear 186 is positioned between the housing 14 and a cover 206 (FIG. 10) that is fastened to the housing 14. The post 34 extends through the cover 206 and is rotatable relative to the cover 206.
In some embodiments, the spur gear 204 includes 12 teeth and has a nominal thickness of approximately 2.8 mm. The nominal outer diameter of the teeth may be between approximately 23.94 mm and approximately 24.06 mm, and the nominal root diameter of the teeth may be between approximately 19.56 mm and approximately 19.72 mm. In some embodiments, the outer diameter of the teeth is approximately 24 mm and the root diameter is approximately 19.6 mm. The large contact surface area between the spur gear teeth provides better engagement with the teeth around the hole 202 to transmit force to the ring gear 186 and reduces the contact stress and wear between the components and tends to reduce slippage between the spur gear 204 and the teeth around the hole 202.
The planet gears 190 are each supported on a pin 210 (FIGS. 8 and 10) extending from a partition or dividing wall 214 of the housing 14. Referring to FIGS. 9 and 10, each planet gear 190 is positioned between and meshes with the both the ring gear 186 and the sun gear 194. Rotation of the ring gear 186 causes the planet gears 190 to rotate about their respective pins 210, which in turn drives the sun gear 194 to rotate about its axis. In the illustrated embodiment, the pins 210 are spaced at equal angular intervals about the spool axis 110, and the drive mechanism 182 includes three planet gears 190; in other embodiments, the drive mechanism 182 may include fewer or more planet gears 190 and the pins 210/gears 190 may be arranged in another manner. In the illustrated embodiment, the gear ratio from the ring gear 186 to the sun gear 194 is approximately 6:1. In other embodiments, the gear ratio may be higher or lower. Furthermore, in other embodiments, the planet gears 190 may be supported (e.g., on a carrier) such that the planet gears 190 may revolve around the spool axis 110.
The drive mechanism 182 is releasably coupled to the spool 106 by an overload clutch mechanism. As shown in FIGS. 9 and 10, the sun gear 194 is formed on one end of a gear member 222 extending along the spool axis 110. A second end of the gear member 222 includes a clutch element 230 (e.g., a jaw clutch) that engages the clutch surface 170 on the spool 106. In the illustrated embodiment, the gear member 222 is aligned with the spool axis 110. In addition, the clutch element 230 may include three jaw clutch teeth 234, which are spaced apart from one another at equal angular intervals around the spool axis 110. The side surfaces of the jaw clutch teeth 234 and the driven clutch teeth 174 are sloped to form an acute angle 236 (FIG. 9) relative to the spool axis 110. The jaw clutch teeth 234 are complementary to the driven clutch teeth 174 such that the jaw clutch teeth 234 fit into spaces or gaps between the driven clutch teeth 174 (and vice versa). The clutch element 230 is biased into engagement with the clutch surface 170 by a biasing element (e.g., a coil spring 238) positioned between the sun gear 194 and the end of the post 34 that engages the ring gear 186.
In some embodiments, the angle 236 is between approximately 45 degrees and approximately 75 degrees. In some embodiments, the heights of the side surfaces of the jaw clutch teeth 234 and driven clutch teeth 174 are between approximately 1.5 mm and approximately 2.5 mm. In some embodiments, the angle 236 is approximately 68 degrees, and the nominal heights of the side surfaces of the jaw clutch teeth 234 and the driven clutch teeth 174 are approximately 2 mm. The nominal spring force applied on the clutch element 230 by the spring 238 during normal operation is between approximately 10 N and 15.4 N (2.25 lbf-3.46 lbf).
During normal operation, a torque applied to the handle 38 rotates of the lever 22, thereby transmitting a torque to the ring gear 186 and the sun gear 194. The jaw clutch teeth 234 fit into the gaps between the driven clutch teeth 174, transmitting torque to the spool 106 to rotate the spool 106 about the spool axis 110. However, in some circumstances, the chalk line device 10 may jam. This may occur due to several reasons: for instance, the chalk line 18 may become caught on an object or wrapped around the outside wall of the spool 106; the chalk in the internal chamber 104 may accumulate adjacent the nozzle 50, making it difficult to reel in the line 18; or chalk may interfere with rotation of the spool 106 or may jam the gears of the drive mechanism 182. In these situations, a user typically applies additional torque on the lever 22, which, in a conventional chalk line device, causes either the line 18 to break or the gears to fracture or strip.
As shown in FIG. 11, if the torque applied by the user exceeds a predetermined level, the jaw clutch teeth 234 will slip relative to the driven clutch teeth 174 of the clutch surface 170 on the spool 106. Stated another way, the sides of the jaw clutch teeth 234 slide along the sloped side surfaces of the driven clutch teeth 174. Due to the angular orientation of the side surfaces, the excessive torque will cause the gear member 222 to overcome the axial biasing force of the spring 238. In some embodiments, the magnitude of the angle 236 of the side surfaces of the jaw clutch teeth 234 at least partially determines the maximum torque before the gear member 222 overcomes the biasing force 238. The gear member 222 will move parallel to the spool axis 110 such that the jaw clutch teeth 234 move out of the gaps between the driven clutch teeth 174. The gear member 222 will continue to rotate until the jaw clutch teeth 234 drop into the next sequential gaps. The gear member 222 will continue to slip relative to the spool 106 if the torque still exceeds the predetermined level.
In some embodiments, the spring force and configuration and/or the dimensions of the clutch teeth 174, 234 are configured to provide a clutch torque (i.e., the torque at which the jaw clutch teeth 234 slip relative to the driven clutch teeth 174) between approximately 25 in-lbf and approximately 45 in-lbf. In one embodiment, the nominal spring force applied on the clutch element 230 by the spring 238 when the clutch element 230 is moving axially to slip relative to the driven clutch teeth 174 is between approximately 24.8 N and 30.2 N (5.58 lbf-6.79 lbf).
The overload clutch mechanism prevents excessive torque from being applied on the transmission components and the spool 106, reducing wear on the gears and preventing the line 18 from breaking. In addition, the free rotation of the lever 22 and post 34 during the overload condition provides a tactile indication to the user that the spool 106 is not rotating due to a jam or over-torque condition, thereby alerting the user to inspect and clean the spool 106 and/or drive mechanism 182. The user may access the internal components by opening the cover 206 on the housing 14 and/or by separating the housing portions 14a, 14b. In the illustrated embodiment, the overload clutch acts at the interface between the spool 106 and the drive mechanism 182 to disengage the spool 106 from the lever 22, rather than acting at the interface between the lever 22 and the drive gears. Because the clutch interface is downstream of the drive gears, even if a large torque is applied on the handle 38, the drive gears reduce the torque applied on the clutch components. This increases the working life of the clutch components due to the lower torque.
During the overload condition described above, the post 34 remains engaged with the ring gear 186 even though the gear member 222 slips relative to the spool 106. However, the drive mechanism 182 also includes a manual disconnect mechanism. Referring again to FIGS. 9 and 10, the post 34 may be manually pressed by a user to move the post 34 parallel to the spool axis 110, disengaging the post gear teeth from the complementary teeth in the hole 202 of the ring gear 186. The post 34 provides a manual disconnect that de-couples the lever 22 from the spool 106 in a different location from the overload clutch mechanism, since the manual disconnect disengages the input (lever 22) from the gears. In other embodiments, the chalk line device 10 may include an overload clutch mechanism as described without a manual disconnect mechanism (i.e., the post 34 may be coupled to the ring gear 186 at all times).
As shown in FIG. 12, the gear components (e.g., the ring gear 186, the planet gears 190, the sun gear 194) are separated from the internal chamber 104 of the housing 14 by the dividing wall 214 in order to prevent chalk from entering the spaces between the gear teeth and interfering with the interaction of the gears. The gear member 222, which extends through the dividing wall 214, includes a flange 246 (FIGS. 9 and 10) abutting the dividing wall 214. Furthermore, as shown in FIGS. 8 and 10, a seal 250 is positioned between the dividing wall 214 and the spool 106. Both the flange 246 and the seal 250 further prevent chalk from leaking into the drive or clutch mechanisms.
Although certain aspects have been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects as described. Various features and advantages are set forth in the following claims.
Patent Application
20180065404
