Patent Application
20080151434
The present invention relates to a lift tab for loading and/or unloading a transducer between first (operating) and second (non-operating) positions, where the lift tab is configured to have low friction as it travels up and/or down a load/unload ramp.
In many devices that include supported transducers for reading and/or writing data, such as magnetic recording head assemblies for example, the support structure of the device is designed with a load/unload mechanism for transporting the supported transducer between operating and non-operating positions. For example, in a hard disc drive, a suspension assembly that supports the transducer is designed to include a lift tab that interacts with a load/unload ramp to move the transducer between an operating position on the disc and a non-operating position off of the disc.
One consideration in the design of a load/unload mechanism is to minimize the friction between the lift tab and the load/unload ramp, so that tribological wear, particle distribution, and power drain caused by friction are reduced. In disc drives for mobile handheld consumer products such as cameras and digital music players, the low mass of the devices limit battery weight (and capacity) so that power drains caused by friction in loading and unloading must be further reduced. Attempts have been made to reduce friction by using coatings on the surface of the lift tab and/or the load/unload ramp, treating the surface of the lift tab with a laser, or modifying the material of the lift tab. While these efforts have in some cases been able to reduce friction, they also add cost and/or complexity to the system. It would be beneficial to reduce friction associated with loading and unloading a transducer in a way that does not affect the cost and complexity of the transducing system.
The present invention provides a low friction lift tab for a transducing system that includes a support assembly for supporting a transducer. The lift tab extends from the support assembly, and has a surface configured to lift the support assembly carrying the transducer up a load/unload ramp. The surface of the lift tab has a radius of curvature of less than 0.013 inches.
Transducing system 10 also includes lift tab 24. Lift tab 24 is located at the distal end of support structure 16 to engage a load/unload ramp (not shown) that transports transducer 12 from a first (operating) position to a second (non-operating) position. For example, in a hard disc drive, lift tab 24 interacts with the load/unload ramp to move transducer 12 between an operating position on the disc and a non-operating position off of the disc.
Systems such as transducing system 10 are known in the art, except that lift tab 24 of transducing system 10 is configured in accordance with the present invention to reduce the friction between lift tab 24 and a load/unload ramp as transducer 12 is transported between first and second positions. A specific description of lift tab 24 is provided below with respect to
Various designs of lift tab 24 were empirically tested to determine the effect of the radius of lift tab 24 on the maximum friction force up a load/unload ramp in a disc drive. Comparative Example A employed a lift tab with a radius of 0.027 inches. Comparative Example B employed a lift tab with a radius of 0.018 inches. Example 1 employed a lift tab with a radius of 0.009 inches. The maximum friction forces generated as the lift tabs traveled up a load/unload ramp were as shown below in Table 1.
As can be seen from the data in
Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
