1. Field of the Invention
The present invention relates to a damper, and more particularly to a damper adapted for a retractable device.
2. Description of Related Art
Many devices have retractable devices mounted inside, the devices, such as electric wire retractor, retractable tape, window curtains or seat belt of the car, provide a retractable force for pulling a string or a belt back. The retractable device has a spiral spring mounted inside, when a foreign force pulls the spiral spring out, the spiral spring will return back automatically when the force is released.
The spiral spring provides a retractable force for the string or the belt, and has the following advantages. First, the spiral spring provides a constant resilience. Second, the distance for retracting the spiral spring is short. Therefore, the volume of the spiral spring is small, and such spring is very convenient for use.
However, the coefficient of elasticity k value of the spiral spring relates to the rate for retracting a string or a belt, i.e. the coefficient of elasticity k value of the spiral spring relates to the retractable force of the spiral spring and whether the spiral spring retracts smoothly. When the coefficient of elasticity k value is small, the retractable force is small so that a string or a belt may not be retracted completely. When the k value is large, the force for retracting a string or a belt will be large and a string or a belt may wind around or make somebody get hurt caused by a fast retracting movement.
To overcome the shortcomings, the present invention tends to provide a damper to mitigate the aforementioned problems.
The primary objective of the present invention is to provide a damper that is applied to a retractable device and improves the safety of using the retractable device.
The damper has a body, a spindle and multiple beads. The body has a base with a through hole, a top cap with a through hole and a cavity defined in the body. The spindle is mounted inside the body and has a spindle body and a transverse post formed on the spindle body. The multiple beads are received inside the cavity in the body and abut the transverse post.
The damper provides a friction by the transverse post abutting and moving over the beads, therefore, when the damper is mounted on a retractable device, the retracting rate of the retractable device may be adjusted conveniently by changing the amount of the beads.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
With reference to
The body (10) has a base (11), a top cap (12) and a cavity (13). The base (11) has a through hole (111) defined therein. The top cap (12) is mounted on the base (11) and has a through hole (121) corresponding to the through hole (111) in the base (11). The cavity (13) is defined between the base (11) and the top cap (12).
The spindle (20) is mounted inside the body (10) and has a spindle body (200) and a transverse post (21). The spindle body (200) has a top end, a bottom post and a sidewall. The top end of the spindle body (200) is mounted inside the through hole (121) in the top cap (12), and the bottom post of the spindle body (200) is mounted through the through hole (111) in the base (11). In a preferred embodiment, the bottom post is a non-circular post and may be a hexagonal post. The transverse post (21) is formed on the sidewall of the spindle body (200) and is received inside the cavity (13) in the body (10).
The bead (30) are received inside the cavity (13) in the body (10) and abut the transverse post (21). The beads (30) may be made of steel, plastic, or any material.
With reference to
When the retractable railing device (40) is used, and the spindle (43) is driven to rotate by the spiral spring (41) to pull the railing (42) back. The spindle (20) of the damper (A) is then driven by the spindle (43) of the retractable railing device (40) with the engagement between the bottom post on the spindle (20) and the hole in the spindle (43).
When the spindle (20) rotates, the beads (30) will block the rotation of the transverse post (21) so as to provide a drag effect to the spindle (20). Therefore, the speed of retracting the railing (42) is reduced, and the retracting rate provided by the spiral spring (41) is effectively damped. In addition, the amount of the beads (30) and the retracting rate of the retractable railing device (40) are in an inverse proportion. When the amount of the beads (30) is decreased, the damper (A) provides a less drag effect to the retractable railing device (40). When the amount of the beads (30) is increased, the damper (A) provides a large drag effect to the retractable railing device (40). Therefore, the damper (A) may control the retractable rate effectively by changing the amount of the beads (30) inside the damper (A).
With reference to
With reference to
The advantages of the damper of the present invention describe as follows.
1. The damper (A, B) provides a friction by means of the transverse post (21) abutting and moving over the beads (30), therefore, the retracting rate of the retractable railing device will be reduced.
2. When the damper (A, B) is applied for a coefficient of elasticity k value device, the device may retract a heavy cord at a lower speed and smoothly.
3. When the retracting rate is reduced, a retractable device will be used safer and prevents a person from getting hurt. In addition, if the coefficient of elasticity k value of the spiral spring (61) is kept at a constant, the retracting force provided by the spiral spring (61) for retracting an object will not be changed even when the damper (A, B) is applied. Therefore, whether the transverse post (21) stops abutting the beads (30) or not, the retracting force provided by the spiral spring is constant.
4. The retracting rate is adjusted by changing the amount of the beads, so it is convenient for adjusting the friction providing by the damper (A, B).
It is to be understood, however, that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.