Patent Description:
A tape measure is a commonly used measuring tool in daily life, and a common steel tape measure is the commonly used measuring tool in construction and decoration, and is also one of an essential tool for a family. A reason why the tape measure can be rolled up is because there is a spring inside it, when pulling out a measuring length, it actually elongates a length of a ruler and the spring, once a measurement is completed, the spring inside the tape measure will automatically contract, and the ruler will also contracts under an action of a spring force. A head of the tape measure is loose for us to measure a size. When measuring the size with a tape measure, there are two measurement methods, one is hanging on an object, and the other is pressing against it. A difference between the two measurement methods is a thickness of an iron sheet at a head of the tape measure. A purpose of loosening the head of the tape measure is to compensate for the iron sheet on the head of the tape measure when it is pressed against the object.

In a process of measuring an inner diameter of the object with a traditional tape measure, it is necessary to observe a scale of the tape measure at a tape guide opening, obtain a scale value, and then add a distance between an housing of the tape measure departing from a side of the tape guide opening and the tape guide opening to obtain the inner diameter of the object, however, when observing the scale value at the tape guide opening, the scale value is often obstructed by the housing of the tape measure, making it difficult to directly look at the scale value, when reading the scale value at an oblique angle, it is easy to misread and cause measurement errors, which needs improvement. Documents <CIT>, <CIT> and <CIT> disclose tape measures of the prior art.

A purpose of the present application is providing a tape measure to solve a problem of measurement errors caused by inconvenient reading of scale values in measuring an inner diameter of objects.

A tape measure according to the invention is defined by the appended claims.

A tape measure includes an housing, a tape reel is connected to the housing, and a ruler tape that is arranged on the tape reel, the housing is provided with a tape guide opening, wherein, the housing is provided with a plurality of positioning components that are spaced at intervals along a circumference of the tape reel, the ruler tape forms a compensation section between the plurality of positioning components and the tape guide opening, the housing is provided with a perspective window corresponding to the compensation section, and the perspective window is provided with a scale alignment line; when the ruler tape is fully retracted, the scale value of the ruler tape corresponding to the scale alignment line is a distance from one side of the housing departing from the tape guide opening to the tape guide opening.

By adopting the above technical solution, when measuring the inner diameter of an object, the perspective window is facing the measurer and the ruler tape is pulled out from the tape guide opening, so that an iron sheet at an end of the ruler tape attached to one side of the inner wall of the object, and one side of the housing departing from the tape guide opening is attached to the inner wall of the other side of the object, looking directly at the perspective window to observe the scale alignment line, reading the scale value corresponding to the scale alignment line, can obtain the inner diameter of the object, effectively reducing measurement errors caused by inconvenient reading of the scale value, and improving the efficiency of measurement at the same time.

The compensation section formed by winding the ruler tape around a plurality of positioning components from the tape reel to the tape guide opening is convenient for reading the scale value of the ruler tape through the perspective window, at the same time, when the ruler tape is fully retracted, the scale value of the ruler tape corresponding to the scale alignment line is the distance from the side of the housing departing from the tape guide opening to the tape guide opening, the scale value of the ruler tape reading from the perspective window is directly the inner diameter of the object to be measured, reduce conversion steps to effectively reduce measurement errors caused by conversion errors.

Optionally, the positioning components comprise a positioning rod that is provided in the housing and an auxiliary bearing that is sleeved on the positioning rod.

By adopting the above technical solution, the bearing guides a direction of the ruler tape, reducing a noise when the ruler tape is pulled out, and reducing a friction force during the movement of the ruler tape, so it is not easy to wear the surface of the ruler tape and improve a smoothness of the ruler tape movement.

Optionally, the housing is provided with a reset element for driving the tape reel to reset and rotate, and the housing is provided with a stop element, an elastic element for driving the stop element to contact the ruler tape, and a control element for driving the stop element to separate from the ruler tape.

By adopting the above technical solution, by pressing the control element, the control element drives the stop element to separate from the ruler tape, making it easier for the ruler tape to be pulled out of the tape guide opening and the tape reel to rotate, at this time, both the elastic element and the reset element undergo elastic deformation and maintain a trend of elastic reset. When the ruler tape is pulled out to a specified length, release the control element, the elastic element is elastically reset and the elastic element drives the stop element to contact a surface of the ruler tape, at the same time, an elastic reset of the reset element drives the tape reel to rotate to retract the ruler tape, due to a contact between the stop element and the surface of the ruler tape, the friction force counteracts the elastic reset force of the reset element, limiting the retract movement of the ruler tape, thereby reducing a possibility of scratching the measurer due to a shaking of the ruler tape caused by a sudden retraction of the ruler tape, and improving a safety of the tape measure.

Optionally, the stop element is rotatably connected to the housing, and the stop element is provided with a contact end, a braking end corresponding to the ruler tape, the control element is rotatably connected to the housing, and the control element is provided with a compression end corresponding to the contact end.

By adopting the above technical solution, by pressing the control element, the control element is driven to rotate, and the compression end contacts the contact end to drive the stop element to rotate, a rotation of the stop element separates the braking end from the surface of the ruler tape, while the elastic element undergoes elastic deformation under force and maintains a trend of elastic reset. When the control element is released, the elastic reset of the elastic element drives the stop element to reset and rotate, and the braking end moves towards the direction facing the ruler tape to contact the surface of the ruler tape, at the same time, the contact end drives the control element to reset and rotate through the compression end.

According to the invention the tape reel is axially provided with a rotating wheel , and the housing is slidably connected with a plurality of speed reduction blocks, a plurality of speed reduction blocks are spaced at intervals along a circumference of the rotating wheel, and a linkage mechanism is provided between the housing and the rotating wheel, the rotating wheel is configured to drive, by means of the linkage mechanism, the speed reduction blocks to slide towards the rotating wheel , the housing is provided with a connector for driving the speed reduction block to reset and slide.

By adopting the above technical solution, when the elastic reset of the reset element drives the tape reel to retract the ruler tape, the tape reel drives the rotating wheel to rotate, the rotating wheel drives a plurality of speed reduction blocks to slide towards the direction facing the rotating wheel through the linkage mechanism, causing the speed reduction block to slide into contact with the circumferential sidewall of the rotating wheel, the connector undergoes elastic deformation under force and maintains a trend of elastic reset, effectively slowing down a speed at which the reset element drives the tape reel to rotate, thereby reducing a possibility of scratching the measurer due to the shaking of the ruler tape caused by the sudden retraction of the ruler tape, and improving a safety of the tape measure.

According to the invention the linkage mechanism comprises a ratchet that is rotatably connected to the housing and coaxial with the rotating wheel, a ratchet pawl that is rotatably connected to the rotating wheel and cooperates with the ratchet, a transmission element that is provided on the rotating wheel and used to drive the ratchet pawl to reset and rotate, and a linkage component that is provided on the housing; the ratchet is configured to rotate to drive, by means of the linkage component, the speed reduction block to slide towards the rotating wheel.

By adopting the above technical solution, when the ruler tape is pulled out, a rotation direction of the rotating wheel at this time causes a thorns of the ratchet to contact the ratchet pawl, causing the ratchet pawl to rotate along a bevels of the thorns towards a direction departing from the ratchet, the transmission element undergoes elastic deformation under force and maintains an elastic reset trend, when the ratchet pawl is located between the two thorns, the transmission element is elastically reset, driving the ratchet pawl to move between the two thorns and circulate in sequence, therefore, a rotation of the rotating wheel cannot drive the ratchet to rotate synchronously.

When the ruler tape is retracted, the rotation direction of the rotating wheel causes the thorns of the ratchet departing from the bevel and contacts the ratchet pawl, at this time, it cannot drive the ratchet pawl to rotate departing from the direction of the ratchet, therefore, the rotation of the rotating wheel can drive the ratchet to rotate synchronously, the rotation of the ratchet can be driven by the linkage component to slide the speed reduction block towards the direction facing the rotating wheel, causing the speed reduction block to slide to contact the circumferential side wall of the rotating wheel, effectively slowing down the speed at which the reset element drives the tape reel to rotate.

Optionally, the linkage component comprises a linkage toothed ring that is provided on a circumferential inner wall of the ratchet, a driving gear and a driven gear that are rotatably connected to the housing, a linkage element that is provided on the driven gear, a fixing element that is provided on the housing for driving the driven gear to reset and rotate; the driving gear is engaged with the linkage toothed ring, the driven gear and the linkage toothed ring are arranged coaxially, and the driving gear is provided with a transmission part that is in clearance transmission with the driven gear.

By adopting the above technical solution, the rotation of the ratchet and a meshing transmission between the linked toothed ring and the driving gear drive the driving gear to rotate, the driving gear drives the driven gear to mesh and drive through the transmission part, at the same time, the driven gear rotates and drives the speed reduction block to slide towards the direction facing the rotating wheel through the linkage element, the fixing element undergoes elastic deformation under force and maintains the trend of elastic reset.

When the transmission part is disengaged from the driven gear for transmission, the fixing element elastically resets and drives the driven gear to reset and rotate, at the same time, the connector elastically resets and drives the speed reduction block to slide departing from the rotating wheel, thus, while slowing down the retraction of the ruler tape, maintaining a certain retraction speed and ensuring the efficiency of tape retraction.

Optionally, a plurality of toothed parts, which are engaged with the driven gear, are provided on a circumferential side wall of the transmission part, and the plurality of toothed parts are spaced along the circumferential side wall of the transmission part.

By adopting the above technical solution, if the toothed part is engaged with the driven gear for transmission, it drives the driven gear to rotate, herein, the fixing element undergoes elastic deformation under force and maintains the trend of elastic reset; if the toothed part is disengaged from the driven gear, then before the next toothed part is engaged with the driven gear, the fixing element elastically resets and drives the driven gear to reset and rotate.

Optionally, the linkage element comprises a linkage rope corresponding to the speed reduction block, a linkage cylinder that is fixedly connected axially to the driven gear, one end of the linkage rope is fixedly connected to the corresponding speed reduction block, and the other end is connected to the linkage cylinder.

By adopting the above technical solution, if the toothed part is engaged with the driven gear for transmission, it drives the driven gear to rotate, herein, the linkage cylinder makes the linkage rope to be retracted, thus driving the speed reduction block to slide towards the direction facing the rotating wheel, causing the speed reduction block to slide to contact a circumferential sidewall of the rotating wheel, herein, the connector undergoes elastic deformation under force and maintains the trend of elastic reset.

If the toothed part is disengaged from the driven gear, the fixing element is elastically reset, which drives the driven gear to reset and rotate, herein, the linkage rope is released from the linkage cylinder, and the connector is elastically reset, thereby driving the speed reduction block to slide departing from the rotating wheel.

Optionally, the speed reduction block is provided with a damping block, and the rotating wheel is provided with a damping ring corresponding to the damping block.

By adopting the above technical solution, the contact between the damping block and damping ring reduces the direct contact between the reduction block and the runner, thereby preventing damage caused by friction between the two, effectively slowing down the speed at which the reset component drives the drum to rotate.

In summary, the present application includes at least one of the following beneficial technical effects:.

The present application will be further described in detail below in combination with the <FIG>.

The embodiment <NUM> of the present application discloses a tape measure.

Referring to <FIG>, a tape measure includes an housing <NUM> that is fixedly connected by screws between a left casing and a right casing and has an internal cavity, a rotating shaft <NUM> that is fixedly connected to an inner wall of the housing <NUM>, a tape reel <NUM> that is rotatably connected to the rotating shaft <NUM>, and a ruler tape <NUM> that is wound around the tape reel <NUM>, one end of the housing <NUM> is integrally formed with a tape guide opening <NUM>.

Referring to <FIG> and <FIG>, the housing <NUM> is provided with three positioning components <NUM>, which are spaced at intervals along a circumference of the tape reel <NUM>, the ruler tape <NUM> extends from the tape guide opening <NUM> around the three positioning components <NUM>, and forms a compensation section <NUM> between the three positioning components <NUM> and the tape guide opening <NUM>. The housing <NUM> is integrally formed with a socket connected to the interior of the housing <NUM>, and there is a perspective window <NUM> corresponding to the compensation section <NUM> in the socket, the perspective window <NUM> is made of transparent material such as transparent resin or glass. The perspective window <NUM> is engraved with a scale alignment line <NUM>, when the ruler tape <NUM> is fully retracted, the scale value of the ruler tape <NUM> corresponding to the scale alignment line <NUM> is a distance from a side of the housing <NUM> departing from the tape guide opening <NUM> to the tape guide opening <NUM>.

Referring to <FIG> and <FIG>, the positioning component <NUM> includes a positioning rod <NUM> that is fixedly connected to the inner wall of the housing <NUM>, and an auxiliary bearing <NUM> that is sleeved on the positioning rod <NUM>.

Referring to <FIG> and <FIG>, the housing <NUM> is provided with a reset element <NUM> for driving the tape reel <NUM> to reset and rotate, the reset element <NUM> is a coil spring sleeved on the rotating shaft <NUM>, one end of the coil spring is fixedly connected to the rotating shaft <NUM> and the other end is fixedly connected to the tape reel <NUM>. The housing <NUM> is provided with a stop element <NUM>, an elastic element <NUM> is used to dive the stop element <NUM> to contact the ruler tape <NUM>, and a control element <NUM> is used to separate the stop element <NUM> and the ruler tape <NUM>.

Referring to <FIG> and <FIG>, the stop element <NUM> is rotatably connected to the housing <NUM>, and a circumferential side wall of the stop element <NUM> is integrally formed with a contact end <NUM> and a braking end <NUM> corresponding to the ruler tape <NUM>. A control element <NUM> is a button block rotatably connected to the housing <NUM>, which is integrally formed with a gap for the button block to extend, one end of the control element <NUM> is integrally formed with a compression end <NUM> corresponding to the contact end <NUM>. The elastic element <NUM> is a V-shaped elastic piece, one end of the elastic piece is embedded on the inner wall of the housing <NUM>, and the other end is in contact with a side of the contact end <NUM> facing the tape guide opening <NUM>.

An implementation principle for embodiment <NUM> of the present application will be described below.

When measuring an inner diameter of an object, the perspective window <NUM> is facing a measurer, pull out the ruler tape <NUM> from the tape guide opening <NUM>, so that the iron sheet at an end of the ruler tape <NUM> is attached to one side of the inner wall of the object, and the housing <NUM> departing from the tape guide opening <NUM> is attached to the inner wall of the other side of the object, look directly at the perspective window <NUM> and observe the scale alignment line <NUM>, read the scale value corresponding to the scale alignment line <NUM> to obtain the inner diameter of the object.

The compensation section <NUM> formed by winding the ruler tape <NUM> around a plurality of positioning components <NUM> from the tape reel <NUM> to the tape guide opening <NUM> is convenient for reading the scale value of the ruler tape <NUM> through the perspective window <NUM>, at the same time, when the ruler tape <NUM> is fully retracted, the scale value of the ruler tape <NUM> corresponding to the scale alignment line <NUM> is the distance from the side of the housing <NUM> departing from the tape guide opening <NUM> to the tape guide opening <NUM>, the scale value of the ruler tape <NUM> read from the perspective window <NUM> is directly the inner diameter of the object to be measured.

By pressing the control element <NUM>, the control element <NUM> drives the stop element <NUM> to separate from the ruler tape <NUM>, making it easier for the ruler tape <NUM> to be pulled out of the tape guide opening <NUM> and the tape reel <NUM> to rotate, at this time, both the elastic element <NUM> and the reset element <NUM> undergo elastic deformation and maintain a trend of elastic reset. When the ruler tape <NUM> is pulled out to a specified length, release the control element <NUM>, the elastic element <NUM> is elastically reset and the elastic element <NUM> drives the stop element <NUM> to contact a surface of the ruler tape <NUM>, at the same time, an elastic reset of the reset element <NUM> drives the tape reel <NUM> to rotate to retract the ruler tape <NUM>, due to a contact between the stop element <NUM> and the surface of the ruler tape <NUM>, a friction force counteracts the elastic reset force of the reset element <NUM>, limiting the retraction movement of the ruler tape <NUM>.

Embodiment <NUM> of the present application discloses a tape measure.

Referring to <FIG>, a difference between embodiment <NUM> and embodiment <NUM> of the present application is that one side of the tape reel <NUM> is fixedly connected axially to a rotating wheel <NUM> that is coaxial with a coaxial centerline of the tape reel <NUM>, the inner wall of the housing <NUM> facing the rotating wheel <NUM> is slidably connected with three speed reduction blocks <NUM>, which are spaced at intervals along a circumference of the rotating wheel <NUM>. A linkage mechanism <NUM> is provided between the housing <NUM> and the rotating wheel <NUM>, and the rotating wheel <NUM> drives the speed reduction block <NUM> to slide towards the direction facing the rotating wheel <NUM> through the linkage mechanism <NUM>. The housing <NUM> is provided with a connector <NUM> for driving the speed reduction block <NUM> to reset and slide, the connector <NUM> is a connecting spring, one end of the connecting spring is fixedly connected to the inner wall of the housing <NUM> and the other end is fixedly connected to the speed reduction block <NUM>. A damping block <NUM> is fixedly connected to one side of the speed reduction block <NUM> facing the rotating wheel <NUM>, and a damping ring <NUM> corresponding to the damping block <NUM> is fixedly connected to a circumferential side wall of the rotating wheel <NUM>. The damping block <NUM> and the damping ring <NUM> are both made of wear-resistant materials such as a rubber.

Referring to <FIG> and <FIG>, the linkage mechanism <NUM> includes a ratchet <NUM> that is rotatably connected to the housing <NUM> and coaxial with the rotating wheel <NUM>, a ratchet pawl <NUM> that is rotatably connected to a circumferential inner wall of the rotating wheel <NUM> and cooperates with the ratchet <NUM>, a transmission element <NUM> that is installed on the rotating wheel <NUM> and used to drive the ratchet pawl <NUM> to reset and rotate, and a linkage component <NUM> that is installed on the housing <NUM>, the ratchet <NUM> rotates and drives the speed reduction block <NUM> to slide in the direction facing the rotating wheel <NUM> through the linkage component <NUM>. The rotating wheel <NUM> is rotatably connected to the ratchet pawl <NUM> through a connecting shaft, and the transmission element <NUM> is a connecting torsion spring sleeved on the connecting shaft, one end of the connecting torsion spring is fixedly connected to the ratchet pawl <NUM>, and the other end is fixedly connected to the rotating wheel <NUM>.

Referring to <FIG> and <FIG>, the linkage component <NUM> includes a linkage toothed ring <NUM> that is fixedly connected to a circumferential inner wall of the ratchet <NUM>, a driving gear <NUM> that is rotatably connected to the housing <NUM>, a driven gear <NUM> that is rotatably connected to the rotating shaft <NUM>, a linkage element <NUM> that is installed on the driven gear <NUM>, and a fixing element <NUM> that is installed on the rotating shaft <NUM> for driving the driven gear <NUM> to reset and rotate. The fixing element <NUM> is a fixed torsion spring sleeved on the rotating shaft <NUM>, one end of the fixed torsion spring is fixedly connected to the rotating shaft <NUM> and the other end is fixedly connected to the driven gear <NUM>. The driving gear <NUM> is engaged with the linkage toothed ring <NUM> for transmission, and the driven gear <NUM> and the linkage toothed ring <NUM> are arranged coaxially, the driving gear <NUM> is fixedly connected with a transmission part <NUM> that is in clearance transmission with the driven gear <NUM>.

Referring to <FIG> and <FIG>, a circumferential side wall of the transmission part <NUM> is fixedly connected with a plurality of toothed parts <NUM> that is engaged with the driven gear <NUM>, and a plurality of toothed parts <NUM> are spaced along the circumferential side wall of the transmission part <NUM>. The linkage element <NUM> includes a linkage rope <NUM> corresponding to the speed reduction block <NUM>, a linkage cylinder <NUM> is axially fixed to the driven gear <NUM>, the linkage cylinder <NUM> is rotatably connected to the rotation shaft <NUM>, one end of the linkage rope <NUM> is fixedly connected to the corresponding speed reduction block <NUM>, and the other end is wrapped and fixedly connected to the linkage cylinder <NUM>.

When the elastic reset of the reset element <NUM> drives the tape reel <NUM> to retract the ruler tape <NUM>, the tape reel <NUM> drives the rotating wheel <NUM> to rotate, the rotating wheel <NUM> drives a plurality of speed reduction blocks <NUM> to slide towards the direction facing the rotating wheel <NUM> through the linkage mechanism <NUM>, causing the speed reduction block <NUM> to slide into contact with the circumferential sidewall of the rotating wheel <NUM>, the connector <NUM> undergoes elastic deformation under force and maintains a trend of elastic reset, effectively slowing down a speed at which the reset element <NUM> drives the tape reel <NUM> to rotate.

When the ruler tape <NUM> is pulled out, a rotation direction of the rotating wheel <NUM> at this time causes a thorns of the ratchet <NUM> to contact the ratchet pawl <NUM>, causing the ratchet pawl <NUM> to rotate along a bevels of the thorns towards a direction departing from the ratchet <NUM>, the transmission element <NUM> undergoes elastic deformation under force and maintains an elastic reset trend. When the ratchet pawl <NUM> is located between the two thorns, the transmission element <NUM> is elastically reset, driving the ratchet pawl <NUM> to move between the two thorns and circulate in sequence. Therefore, a rotation of the rotating wheel <NUM> cannot drive the ratchet <NUM> to rotate synchronously;.

Claim 1:
A tape measure, comprising: an housing (<NUM>), a tape reel (<NUM>) that is connected to the housing (<NUM>), and a ruler tape (<NUM>) that is arranged on the tape reel (<NUM>), wherein the housing (<NUM>) is provided with a tape guide opening (<NUM>), the housing (<NUM>) is provided with a plurality of positioning components (<NUM>) that are spaced at intervals along a circumference of the tape reel (<NUM>), a compensation section (<NUM>) is formed on the ruler tape (<NUM>) between the plurality of positioning components (<NUM>) and the tape guide opening (<NUM>), the housing (<NUM>) is provided with a perspective window (<NUM>) corresponding to the compensation section (<NUM>), and the perspective window (<NUM>) is provided with a scale alignment line (<NUM>); when the ruler tape (<NUM>) is fully retracted, a scale value of the ruler tape (<NUM>) corresponding to the scale alignment line (<NUM>) is a distance from one side of the housing (<NUM>) departing from the tape guide opening (<NUM>) to the tape guide opening (<NUM>), characterised in that the tape reel (<NUM>) is axially provided with a rotating wheel (<NUM>), the housing (<NUM>) is slidably connected with a plurality of speed reduction blocks (<NUM>) that are spaced at intervals along a circumference of the rotating wheel (<NUM>), a linkage mechanism (<NUM>) is provided between the housing (<NUM>) and the rotating wheel (<NUM>), the rotating wheel (<NUM>) is configured to drive, by means of the linkage mechanism (<NUM>), the speed reduction blocks (<NUM>) to slide towards the rotating wheel (<NUM>), and the housing (<NUM>) is provided with a connector (<NUM>) for driving the speed reduction block (<NUM>) to reset and slide,
the linkage mechanism (<NUM>) comprises a ratchet (<NUM>) that is rotatably connected to the housing (<NUM>) and is coaxial with the rotating wheel (<NUM>), a ratchet pawl (<NUM>) that is rotatably connected to the rotating wheel (<NUM>) and cooperates with the ratchet (<NUM>), a transmission element (<NUM>) that is provided on the rotating wheel (<NUM>) and is configured to drive the ratchet pawl (<NUM>) to reset and rotate, and a linkage component (<NUM>) that is provided on the housing (<NUM>); the ratchet (<NUM>) is configured to rotate to drive, by means of the linkage component (<NUM>), the speed reduction block (<NUM>) to slide towards the rotating wheel (<NUM>).