Rotary shafts – gudgeons – housings – and flexible couplings for ro – Overload release coupling
Reexamination Certificate
2000-01-19
2002-03-26
Browne, Lynne H. (Department: 3629)
Rotary shafts, gudgeons, housings, and flexible couplings for ro
Overload release coupling
C269S244000, C464S037000
Reexamination Certificate
active
06361442
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally concerns a handle for a machinist's vise.
The present invention particularly concerns handles or machinist's vises known in the art as “speed” handles and particularly to an economical “speed” handle in which the maximum torque that can be applied to the handle is limited to a preset value so as to limit the clamping force applied by the jaws of the vise to the part being clamped.
2. Description of the Prior Art
The machinist's vise is a well known devise in the machining art for holding a part being machined on the table of a mill as the milling cutter machines the part. The typical machinist's vise is bolted onto the table surface of the mill and has a horizontal screw abutting a jaw of the vise and another end on which a handle is mounted and turned such as to clamp the jaws of the vise on the part. The part must be held very firmly to prevent slippage in the vise which could result in ruining the part. However, in numerous instances, particularly when the part has a thin section, the clamping force of the vise can at least temporarily deform the part resulting in a necessity to make adjustments in machining the part to maintain tolerance.
Variations in clamping force from one part to the next can result in variations of the machining dimensions which are greater than the machining tolerance. These variations in clamping force arise from differences between force applied by different operators or even with one operator such as may arise from fatigue.
A number of modifications of the machinist's vise have been disclosed related to speed opening and closing the vise and applying controlled clamping force.
U.S. Pat. No. 5,192,062 to Berchtold discloses a clamping force adjusting devise for a clamping devise such as a vise which requires a force multiplier attached to a clamping rod.
U.S. Pat. No. 4,738,438 to Horie, et al., discloses a machine vise with a strain gage detector devise enabling the operator to control applied clamping force.
U.S. Pat. No. 4,046,364 discloses a torque limiting devise having a handle portion coupled to the drive screw of the vise through a friction clutch constructed as an integral part of the vise in which frictional force between the clutch disks can be pre adjusted to permit slip when the torque applied to the handle portion exceeds a preset value. The handle is also coupled to the drive screw of the vise by a shrag clutch which is disengaged when the handle is turned in the direction to tighten the vise and is disengaged in the opposite direction so as to provide a positive coupling to retract (loosen) the vise jaws. The construction of the vise requires application of a spanner wrench to adjust the frictional limiting force of the clutch mechanism and the adjustment of the frictional limit force of the clutch mechanism is integral to the base of the vise.
U.S. Pat. No. 5,192,062 for a CLAMPING FORCE ADJUSTING DEVISE FOR A CLAMP DEVISE concerns a clamping force adjusting devise having a hollow housing supported on a movable clamping part of the same, through which housing passes a rotatable and slidable tension rod whose first end can be coupled to a force amplifier and whose second end carries a tension sleeve fixed thereon. The tension sleeve is supported on Belleville springs through a thrust bearing and an intermediate sleeve, the Belleville springs being supported directly in the housing. An adjusting sleeve screws into a fine thread of the housing and has at its end facing the Belleville springs a radially inwardly directed first stop shoulder, which cooperates with a radially outwardly directed second stop shoulder of the intermediate sleeve and/or a spacer ring bearing on the thrust bearing. Belleville springs will be seen to be employed in the preset torquing force vise handle of the present invention.
A prior art patent that is directed to a vise handle fulfilling the same purposes as does the handle of the present invention is U.S. Pat. No. 5,683,077 for a VISE HANDLE WITH TORQUE CONTROL. Indeed, certain of the description regarding the background of vise handles and force-controlled clamping that appears within that patent is within the Description of the Prior Art section of the instant specification. The 5,683,077 patent concerns a handle for a machinists vise configured to preset the maximum clamping force that can be applied to the vise jaws. The handle is constructed such that, in tightening the vise, when a clamping force is applied by the operator to the handle equal to a preset value, a clutching mechanism in the handle will allow the handle to slip without further tightening of the vise. The mechanism includes a ratchet for positive engagement in loosening the vise and for providing a clicking sound that the clutch is slipping and thereby alert the operator that maximum clamping force is being applied.
Accordingly, both the handle of the '077 patent, and the handle of the present invention, have as their objects the provision of a handle attachable to the drive screw of the standard machinist's vise for use in turning the drive screw to apply a preset clamping force on a part. This handle is suitably used with the typical (off the shelf) machinist's vise. The handle can be adjustably preset so as to apply a particular vise to which the handle is currently affixed and used to apply a correspondingly preset clamping force. The handle will elicit a signal to the operator that slipping of the handle is occurring when the torquing force applied to the handle, and the corresponding clamping force of the vise, reaches a preset value.
Further in common with the handle of the '077 patent, it is an object of the handle of the present invention that the operator can preset a value of force with convenience. It is another object that the maximum force applied to the handle of the vise be more closely controlled than the devises of the prior art. It is still yet another object that the invention have a simple and robust construction, and be economical to build.
SUMMARY OF THE INVENTION
The present invention contemplates a compact, effective, reliable and economical torque-limiting handle for a machinist's vise.
The torque-limiting handle is a slender cylinder in form, being built along an internal shaft. The maximum torque that may be transmitted by the torque-limiting handle is determined by rotation of an external sleeve under force of the fingers. This rotation may readily be accomplished under but even, slight, force regardless that the handle is being preset to transmit low, or high, torque. To facilitate the assumption, and holding, of certain preset torque values, the rotational sleeve is preferably possessed of detents and/or markings, making accurate setting of the sleeve, and the torque-limiting handle, both easy and speedy.
When such torque in a one, vise-tightening, rotational direction as is attempted to be transmitted along the torque-limiting handle reaches the preset limit, the torque-limiting handle will thereafter continue to turn, but will slip in the manner of a ratchet between its driven and driving ends. The slipping handle will make such a sound, and will present such diminished pressure to the hand, as will make clear to the user that the preset torque has been reached, and that the torque-limiting handle is ineffective to transmit any greater torque. The preset maximum tightening torque that is transmitted corresponds to a preset maximum clamping force of the machinist's vise upon which the torque-limiting handle is being used.
There are no limits on the torque that can be transmitted when the torque-limiting handle is turned in a second, vise-opening, rotational direction. It is thus always possible to positively apply any necessary torque to open the vise, even if such torque must exceed (in a different rotational sense) the preset torque limit.
Such wear, and metal fatigue, as the parts of the torque-limiting handle are subject to does not obviate their function. Being
Adams Craig
Dillenberger Eric
Browne Lynne H.
Dunwoody Aaron
Fuess & Davidenas
ProTech Engineering
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