Machine element or mechanism – Mechanical movements – Rotary to or from reciprocating or oscillating
Reexamination Certificate
1997-11-06
2001-02-13
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Mechanical movements
Rotary to or from reciprocating or oscillating
C074S08400R
Reexamination Certificate
active
06186014
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a cam driven mechanism in which the rotating torque applied to a roller gear cam is converted to the oscillating rotational movement of a turret and an output shaft by means of a cam follower.
2. Description of the Related Art
The type of cam mechanism mentioned above, which has been proposed by Japanese utility model publication 7-52444 (Int.Cl.F16H 37/16), operates by means wherein the rotating movement input to a cam mechanism is converted into a oscillating rotational movement of an output shaft on the radial axis, and also a reciprocating movement of the output shaft in the axial direction. This type of mechanism is commonly applied to the tool changing mechanisms of metal processing machines with the purpose of obtaining a fast and precise tool change indexing action.
The aforesaid cam mechanism incorporates a roller gear cam fixedly attached to the input shaft, tapered ribs formed on the cam's periphery, and a cam channel formed on one of the cam's lateral surfaces. A roller cam follower, which is supported by a turret piece, rides between the aforesaid tapered ribs on the cam's periphery, and a swing arm rides in the aforesaid cam channel on the cam's lateral surface by means of a cam follower pin. An output shaft is installed through the turret's center by means of a sliding spline joint which fixedly connects the shaft to the turret in the radial direction, but allows free axial movement of the shaft through the turret piece in the axial direction. The end of the aforesaid swing arm is installed to the output shaft.
As a result of this configuration, the rotating movement of the input shaft is converted to an oscillating rotational movement of the output shaft by means of the aforesaid turret, and further converted to a reciprocating movement of the output shaft in the axial direction by means of the aforesaid swing arm.
A conventional cam mechanism of the type delineated above incorporates a turret whose cross section is shown in FIG.
11
. As turret
1
is connected to output shaft
2
by means of a sliding spline joint, spline shaft
2
a
of output shaft
2
is of a square cross section which approximately corresponds to the square cross section of spline orifice
1
a
in turret
1
. Peripheral surface
1
b
of turret
1
is of a round shape in radial cross section, and has installed to it six roller type cam followers
3
. Cam followers
3
, which ride in the area defined between the aforesaid tapered ribs
4
on the periphery of the aforesaid roller gear cam, are disposed around the periphery of turret
1
at regular intervals with their rotational centerlines C radiating from the center of turret
1
and output shaft
2
.
As a total of six cam followers
3
are disposed around the periphery of turret
1
, their orientation in relation to rectangular spline orifice
1
a
results in varying amounts of material existing between each cam followers
3
and output shaft
2
. In other words, the volume of material in turret
1
between cam followers
3
and output shaft
2
is greatest in the area at the center and opposite to the flat surfaces of spline orifice
1
a
, and smallest in the areas adjacent to the corners of spline orifice
1
a
. As all of the six cam followers
3
cannot be oriented directly opposite the planar surfaces of spline orifice
1
a
where the volume of material is greatest, some of the cam followers
3
must be positioned in a way which reduce the amount of material between the cam follower
3
and spline orifice
1
a.
As a result of this configuration, turret
1
must be designed so as to provide adequate strength and rigidity around the cam followers
3
which are supported by the smallest volume of material in relation to the splined orifice
1
a
, and in doing so there is created a surplus of rigidity and strength in the area where the cam followers
3
are supported by the largest amount of material. The result is that the periphery of turret
1
is made to relatively large dimensions which, in turn, results in the problem of the entire cam mechanism being made to a larger size than is desirable.
SUMMARY OF THE INVENTION
This invention provides means by which the aforesaid cam followers can be disposed on the turret in the areas where there is maximum material between the cam follower and rectangular spline orifice, thus maintaining adequate turret rigidity and strength, and thus allowing the entire cam mechanism to be made to a smaller size.
In order to resolve the shortcomings mentioned above, the invention proposes a cam mechanism comprised of a roller gear cam solidly and fixedly attached to an input shaft, tapered ribs formed in a geometric curve pattern on the outer periphery of the roller gear cam, and a turret into whose center is formed a rectangular spline orifice. The turret is driven with an oscillating rotational movement by the rotation of roller gear cam through four cam followers which are located directly opposite and adjacent to the planar sides of the spline orifice formed in the turret center. The cam followers ride between the aforesaid tapered ribs on the roller gear cam periphery in a manner whereby the rotating movement of the roller gear cam is converted into an oscillating rotational movement of the turret.
Furthermore, the turret may be formed with the cam follower support pins as solid and integral components of the turret.
The geometrically curved tapered ribs on the roller gear cam periphery may be widened by increasing the width of the tapered rib in areas where it is desired to obtain more precise positioning movement for the aforesaid output shaft.
The invention further proposes a cam mechanism comprised of a roller gear cam solidly and fixedly attached to an input shaft, tapered ribs formed in a geometric curve pattern on the periphery of the roller gear cam, and a turret into whose center is formed a square spline orifice. The turret supports four cam followers located directly opposite and adjacent to the planar sides of the square spline orifice. These cam followers ride between the aforesaid tapered ribs on the roller gear cam periphery in a manner whereby the rotating movement of the roller gear cam is converted into an oscillating rotational movement of the turret. In this version the aforesaid turret is structured in a manner in which the pins supporting the cam followers are formed as a solid and integral part of the turret.
The invention further proposes a cam mechanism comprised of a roller gear cam solidly and fixedly attached to an input shaft, tapered ribs formed in a geometric curve pattern on the outer periphery of the roller gear cam, and a turret into whose center is formed a rectangular spline orifice. The turret supports four cam followers which are located directly opposite and adjacent to the planar sides of the rectangular spline orifice formed in the aforesaid turret, said four cam followers riding between the aforesaid tapered ribs on the roller gear cam periphery in a manner whereby the rotating movement of the roller gear cam is converted into a oscillating rotational movement of the turret. An output shaft is connected to the turret by means of a splined part which inserts into the spline orifice in the turret in a manner which allows free axial movement of the output shaft while it is rotatably held in its radial position supported by the turret. A reciprocating mechanism drives the output shaft with a linear reciprocating movement in the axial direction in synchronization with the output shaft's rotation on its radial axis. The spline in the turret is formed to a square cross section, and each cam follower on the turret's periphery is radially disposed directly facing one planar surface of the square spline orifice in the turret.
Moreover, the pins supporting the cam followers are formed as solid and integral components of the turret itself.
Furthermore, the turret's spline orifice may be formed to a square cross section, and the splined part of the output s
Fenstermacher David
Morrison & Foerster / LLP
Sankyo Manufacturing Co. Ltd.
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