Tool driving or impacting – Impacting devices – With impact cushioning means
Reexamination Certificate
2000-07-31
2001-11-27
Smith, Scott A. (Department: 3721)
Tool driving or impacting
Impacting devices
With impact cushioning means
C173S132000, C173S213000, C408S143000, C279S157000
Reexamination Certificate
active
06321855
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to anti-vibration adaptors. More specifically, the present invention relates to anti-vibration adaptors which, when employed in conjunction with standard powered fastener drivers and socket-type driven heads, increases the torque transmitted to a fastener and decreases vibration experienced by the fastener driver which is subsequently transmitted to the operator.
DESCRIPTION OF THE PRIOR ART
Power fastener drivers such as pneumatic or electric powered pulse and/or impact wrenches as well as anglehead and/or straight nut runners, referred to herein simply as drivers, are well known in industrial environments. In particular in the automotive industry these types of drivers are used extensively in the assembly of automobiles. Typically such drivers comprise a pistol or club-style main body, a trigger, airline connections and a drive shaft which removably connects with any one of a plurality of driver heads and/or drive shaft extensions.
The driver heads comprise a plurality of various sized Imperial or SAE type sockets and screwdriver fittings, herein referred to as sockets, all of which are used to drive or “run down” a variety of fasteners including nuts and bolts. The variety of sockets available varies with the head style of the fastener. For example, while hexagonal type bolt heads are common, Allen-type and Torx-head bolts are are also used extensively in the automobile industry in a variety of sizes. Typically, the connection between the driver and the socket is accomplished via a male square drive connector on the drive shaft of the driver and a complementary female square drive connector on the socket which may be snapped together and retained by a spring pin disposed through the surface of the male square drive connector. However, other snap-on connector profiles are available which are equally effective. Generally these tools are designed to enable the operator to change sockets quickly depending on the size or head style of the fastener to be run-down, hence the popularity of these types of snap-on connections. However, due to the frequency of socket changes and the fact that the sockets are mass produced items, the majority of these types of drivers and sockets, including automotive industrial grade tooling, are not designed to close tolerances and have relatively large mating clearance. In most instances the resulting connection between the driver and the socket will suffer from two degrees of freedom, first the socket will be free to rotate a few degrees relative to the rotational position of drive shaft and second the rotational axis of the socket will be free deviate a few degrees from the rotational axis of the drive shaft.
In operation, deviation of the rotational axis of the socket from the rotational axis of the drive shaft will result in a circular motion of the end of the drive shaft and vibration of the driver. The relative freedom of rotation of the socket with respect to the drive shaft, particularly when the driver is an impact or pulsing driver, results in vibration of the driver and socket components relative to each other. Consequently, the tool operator is exposed to these vibrations which are transferred through the tool to the operator's hands and arms. In an environment such as the automotive industry where a typical assembly worker's primary function is to operate these drivers, these vibrations can cause serious physical injury. Further, the vibrations result in substantially elevated noise levels which can result in the operator suffering from permanent hearing loss if exposed for sufficient periods of time.
These vibrations have other detrimental effects. In particular, excessive vibration can cause premature breakdown of the internal bearings of the driver. Further, in many circumstances, such as the production of automobiles, fasteners are designed to be installed with a specific torque to which the drivers are preset. The vibrations result in losses in torque applied to the fastener which consequently results in fasteners not tightened to specification during production which results in poor statistical process control.
Overall the above-identified disadvantages of typical socket-driver connections result in torque losses, quality control and operator health problems which increase manufacturing costs and/or reduce final product quality. Therefore there is a long standing need in industry for an apparatus which reduces vibration when employed with a standard driver and socket.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel anti-vibration which mitigates at least one of the above described disadvantages of the prior art.
According to one aspect of the invention there is provided an anti-vibration adaptor for use with a standard releasable connection between the drive shaft of a driver and a socket the adaptor comprising: a housing which extends at least partially over both said drive shaft and said socket; a damping means disposed within said housing surrounding, but not intervening between the parts said releasable connection and enclosing at least a portion of said drive shaft and said socket with negligible clearance such that any misalignment of the rotational axes of the drive shaft and said socket is minimized.
According to another aspect of the present invention there is provided an anti-vibration adaptor for use with a driver having a drive shaft and socket coupled to said drive shaft through a releasable connection the adaptor comprising: a hollow cylindrical housing for enclosing said releasable connection and extending at least partially over both said drive shaft and said socket; damping means disposed in said housing having a first bore disposed in one of its ends, coaxially aligned and in communication with a second bore disposed in its opposite end; said first bore having a diameter to permit it to releasably receive a cylindrical portion of said drive shaft with negligible clearance or limited interference and said second having a diameter to permit it to releasably receive a cylindrical portion said socket with negligible clearance or limited interference whereby misalignment of the axes of rotation of said drive shaft and said socket is minimized and rotation of said drive shaft with respect said socket is inhibited.
The present invention further includes an anti vibration adaptor for use in association with a driver having a drive shaft releasably secured by a coupling to an extension shaft comprising: a housing which extends over said coupling and over at least a portion of said drive shaft and said extension shaft, said housing enclosing damping means which surrounds, but does not intervene between, said portions of said drive shaft and said extension shaft, with negligible clearance or slight interference.
Preferably said damping means is formed from Ultra High Molecular Weight (UHMW) polyethylene.
In accordance with the present invention the housing is preferably in the form of a hollow cylinder formed from any one of steel, stainless steel, aluminum, copper, brass, cast iron, and titanium, fibreglass, carbon fibre composites and plastics.
The present invention includes anti-vibration adaptors which fit tightly over both that portion of the socket that contains the releasable connection and a portion of the drive shaft, but does not intervene between the drive shaft and the socket, thereby substantially eliminating axial misalignment of the rotational axis of the socket and the rotational axis of the drive shaft and additionally inhibiting rotational movement of the drive shaft with respect to the socket.
Advantages of the present invention include an anti-vibration adaptor which tightly fits over the conventional joint between a drive shaft on a fastener driver and a driver head thereby eliminating any run-out in the joint.
Advantages of the present invention include reduction of vibration due to misalignment of the rotational axes of the drive shaft and the socket and/or rotational movement of the drive shaft with r
McConnell and Fox
Smith Scott A.
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