Machine element or mechanism – Mechanical movements – Rotary to or from reciprocating or oscillating
Patent
1997-02-17
1998-06-23
Marmor, Charles A.
Machine element or mechanism
Mechanical movements
Rotary to or from reciprocating or oscillating
128317, 30218, 30392, F16H 2152, B27B 1900
Patent
active
057689334
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention concerns a motion converter for changing rotational motion to reciprocal angular motion. This apparatus is particularly useful in sawing tools.
BACKGROUND ART
Motion converters converting rotation into to-and-fro displacement have long been known. Illustratively, they are used for motor-driven surgical saws, though they are also applicable to many other industrial fields.
A motor-driven surgical saw comprising such a motion converter is disclosed, for instance, in U.S. Pat. No. 3,905,105 and 3977289. The saw is fitted with an elongated saw-blade holder bearing a saw blade and supported in a saw housing. The holder is linked at an end away from the saw blade to a cam pin connected to a drive motor shaft. At its middle, the saw-blade holder is supported in the saw-blade housing so as to be pivotable and longitudinally displaceable by a guide pin and, when the motor is running, it is pivoting. The saw blade rigidly joined to the saw-blade holder thereupon carries out to-and-fro motion a fixed excursion predetermined by the design of the motion converter.
This known motion converter has the drawback that the excursion of the to-and-fro motion cannot be changed in a simple manual manner but instead at best requires refitting the motion converter. In many instances such as during surgery, however, a simple, manually implemented change would be advantageous.
SUMMARY OF THE INVENTION
Accordingly an object of the present invention is to create a motion converter which allows adjustment of the excursion of the to-and-fro motion produced by the motion converter without the need for refitting the surgical device.
This problem is solved by the features of the inventive motion converter, which includes a tubular housing, a tool holder pivotally mounted in the housing at a pivot point and including a tool which extends away from the pivot point and out of the housing, and a holder head which extends away from the pivot point and into the housing, and a transmission element pivotably mounted in the housing. The transmission element has a first end which receives the holder head of the tool holder, and a second end which is adapted to receive an eccentrically rotating drive head such that the transmission element pivots back and forth due to eccentric rotation of the drive head and transfers such motion to the holder head of the tool holder which in turn imparts reciprocal angular motion to the tool. The transmission element can be positioned at different locations between the drive head and holder head to adjust the amount of reciprocal angular motion of the tool.
In the invention, the transmission of motion is advantageously implemented by a rocking fork of which the center of rotation can be shifted between the drive and the driven assembly along the longitudinal axis, i.e., the x axis. Thereby, the lever ratio is adjusted and consequently a change in angular position takes place on the driven side. This operation may be likened to an electric amplifier which is able to equally raise and lower a base signal.
BRIEF DESCRIPTION OF THE DRAWINGS
Invention is illustratively elucidated in relation to the drawings wherein.
FIG. 1 is a partial view of an operational system with a motion converter of the invention,
FIG. 2 is a schematic view of a motion converter of the invention in a first position,
FIG. 3 is a schematic view of the motion converter of FIG. 2 in a second position,
FIG. 4 is a schematic view of the motion converter of FIG. 2 in a third position, and
FIG. 5 is a schematic view of the motion converter of rig. 2 in a fourth position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The same components are denoted by the same references wherever they appear in the Figures and therefore all Figures are discussed jointly hereunder.
FIGS. 2 through 5 show a motion converter 3 of the invention in various states. This motion converter 3 comprises a drive shaft 4 connecting the converter to a motor, not shown, and bearing a drive head G. A transmission element 7 is connected by f
REFERENCES:
patent: 2439262 (1948-04-01), Nalbach et al.
patent: 3365963 (1968-01-01), Happe
patent: 3505733 (1970-04-01), Holden
patent: 3905105 (1975-09-01), Tuke
patent: 3977289 (1976-08-01), Tuke
patent: 4827615 (1989-05-01), Graham
patent: 5237884 (1993-08-01), Seto
Herzog Daniel
Tanner Peter
Fenstermacher David M.
Marmor Charles A.
Synthes
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