Method and Apparatus for Installing a Snap-Ring in a Snap-Ring Groove and Detecting Proper Radial Expansion Thereof

The present invention relates to an apparatus for installing a snap ring which detects whether the snap ring has expanded radially outwardly into a snap ring groove.

Many components, particularly vehicle components, include snap rings mounted within an annular groove on an inner surface of the component. The snap rings secure an inner subcomponent within an outer subcomponent. Typically, an outer subcomponents generally has a generally cylindrical inner surface. An annular snap ring groove is formed on the inner surface of the outer subcomponent. An inner subcomponent is inserted in the outer and the snap ring moves into the groove to secure the two. This process is often used to secure to clutch components.

Generally, a machine for installing the snap ring includes a press which moves the snap ring axially into the outer subcomponent. The press typically includes an inwardly tapered surface which compresses the snap ring radially inwardly as the snap ring is inserted into the component. The snap ring is moved to be aligned with the groove and is then released. The snap ring should expand radially outwardly into the snap ring groove.

Known machines have been provided with a sensor for determining whether the snap ring has been inserted sufficiently axially into the vehicle component such that the snap ring should be aligned with the annular groove. Although aligned with the snap ring groove, the snap ring will sometime fail to expand radially outwardly into the snap ring groove, resulting in a defective product. The known machine does not insure that the snap ring is properly expanded radially outwardly into the snap ring groove.

The present invention provides a machine for installing a snap ring which detects whether the snap ring has expanded radially outwardly fully into the snap ring groove.

The snap ring installation machine of the present invention generally comprises a press movable toward a work holding station which carries inner and outer subcomponent. The outer subcomponent has an inner surface with an annular snap ring groove. The press generally comprises a upper assembly and a lower assembly both movable axially toward the component. The lower press assembly includes an outer housing and an inner press assembly. The outer housing includes a generally cylindrical inner surface having an inwardly tapered portion at a lower end. The inner press assembly and outer housing are each movable axially relative to the upper press assembly. A first plurality of heavy springs are disposed between the upper press assembly and the outer housing. A second plurality of heavy springs are disposed between the upper press assembly and the inner press assembly. The inner press assembly further includes a plurality of arms having upper ends extending generally downwardly and biased radially outwardly. A first end of each arm includes an abutment surface adjacent a notch. The notch is radially outward of the abutment surface. A switch is positioned between the upper press assembly and the lower press assembly.

During installation, the upper press assembly and lower press assembly are moved axially toward the subcomponents until the outer housing contacts the subcomponents. The upper press assembly and inner press assembly continue to move axially toward the component, and the arms of the inner press assembly move the snap ring axially downwardly into the outer subcomponent. The abutment surfaces of the plurality of arms abut the snap ring to move it axially downwardly. The snap ring is compressed radially inwardly as it moves axially through the inwardly tapered portion of the outer housing. The snap ring is inserted axially into the component until the snap ring reaches the snap ring groove. If the snap ring expands radially outwardly into the snap ring groove of the component, the snap ring will fit into the notches of the plurality of arms. Thus, the inner press assembly can move downwardly such that the abutment surfaces on the arms move beyond the snap ring. However, if the snap ring does not expand radially outwardly or if it expands insufficiently, at least one of the abutment surfaces of the plurality of arms will contact the snap ring. This stops the downward motion of the inner press assembly, compressing the springs between the upper press assembly and inner press assembly and causing relative axial movement between the upper press assembly and inner press assembly. Relative axial movement between the upper press assembly and inner press assembly activates a switch mounted between the upper press assembly and inner press assembly, thereby indicating that the snap ring did not fully expand into the snap ring groove.

The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:

FIG. 1 is a side view of the snap ring installation apparatus of the present invention;

FIG. 2 is a front view of the apparatus of FIG. 1;

FIG. 3 is a plan view of the apparatus of FIG. 1;

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3;

FIG. 5 is an enlarged view of the area 5 of FIG. 4;

FIG. 6 is a view similar to FIG. 4 of the apparatus when the snap ring is expanded radially into the snap ring groove;

FIG. 7 in an enlarged view of the area 7 of FIG. 6;

FIG. 8 is a view similar to FIG. 6 wherein the snap ring has not expanded into the snap ring groove;

FIG. 9 is an enlarged view of the area 9 of FIG. 8;

FIG. 10A is a sectional view taken along line 10--10 of FIG. 3;

FIG. 10B shows a switch schematically; and

FIG. 11 is an exploded perspective view of the switch of FIG. 2.

A snap ring installation apparatus 20 according to the present invention is shown in FIG. 1. The snap ring installation apparatus 20 installs a snap ring (not shown) into an annular snap ring groove 24 of a first component 26 to secure a second component 28 to the first component 26. The snap ring groove 24 of the first component 26 is formed on a generally cylindrical inner surface of the first component 26 circumferentially about the axis of the first component 26. This machine is particularly useful for securing clutch components.

The snap ring installation apparatus 20 generally comprises an upper press assembly 32 and a lower press assembly 36, both movable axially toward and away from the components 26 and 28. The lower press assembly 36 includes an outer cylindrical housing 38 having a slot 40 formed partially about the circumference of the housing 38 for inserting a snap ring radially into the housing 38 from a machine 41. Machine 41 is generally known in the art, is not part of the present invention and is shown schematically.

As can be seen in FIG. 2, a plurality of springs 46 are circumferentially spaced and disposed between the housing 38 and the upper press assembly 32. A lever 50 is pivotally mounted to the upper press assembly 32 and includes a leg 52 extending downwardly. A lateral extension 53 extends laterally from an opposite end of the lever 50. A finger 54 extends upwardly from the extension 53 into an optical switch 56. The lever 50 is pivotally mounted to the upper press assembly 32 between the leg 52 and the finger 54. The finger 54 end of the lever 50 is spring biased upwardly. The lateral extension 53 of the lever 50 includes a recess 57 into which half of the optical switch 56, i.e. the transmitter or receiver, is normally disposed.

As can be seen in FIG. 3, the lever 50 is mounted to the upper press assembly 32 and pivots on a fulcrum 58 between the leg 52 and the finger 54. The finger 54 extends upwardly from the lateral extension 53 from an end 59 of the lever 50. The lateral extension includes the elongated recess 57 extending generally between the end 59 of the lever 50 toward the finger 54.

Referring to FIG. 4, the lower press assembly 36 further includes an inner press assembly 60 which is movable axially relative to the upper press assembly 32. Further, the outer housing 38 is movable axially relative to the inner press assembly 60 and the upper press assembly 32. A plurality of heavy springs 62 are mounted between the upper press assembly 32 and the inner press assembly 60. The inner press assembly 60 includes a plurality of arms 66 (one shown) circumferentially spaced about the inner press assembly 60. Each of the arms 66 includes a first end 68 extending downwardly. A spring 76 is secured to the upper press assembly 32 and to the arm 66 opposite the first end 68. The arm 66 is pivotally mounted at 77 to the inner press assembly 60 between the first end 68 and the spring 76. Thus, the first end 68 of each of the arms 66 is biased radially outwardly against a generally cylindrical inner surface 80 of the housing 38. The inner surface 80 of the housing 38 includes an annular inward projection 81 spaced from a lower end of the housing 38. The annular projection 81 has an inwardly tapered surface 82 adjacent an axial engagement surface 83. The housing 38 further includes a generally cylindrical portion 84 between the engagement surface 83 and the lower end of the housing 38.

Slot 40 is shown, and as described above, a machine 41 moves snap rings through slot 40 to be inserted by the machine.

As can be seen in FIG. 5, the first end 68 of each arm 66 has an abutment surface 86. A notch 88 is formed in the first end 68 of each of the arms 66 radially outwardly adjacent to the abutment surface 86.

During operation, a snap ring 90 is inserted into the housing 38 through the slot 40. The snap ring 90 is initially positioned just below the plurality of arms 66 adjacent the abutment surfaces 86. The upper press assembly 32 and lower press assembly 36 are then moved downwardly toward the component 26 until the component 26 is received within the lower cylindrical portion 84 of the housing 38. When the component 26 abuts the engagement surface 83 of the housing 38, the upper press assembly 32 and inner press assembly 60 continue to move downwardly, thereby compressing springs 46. Simultaneously, the downward movement of the inner press assembly 60 and the plurality of arms 66 causes the abutment surfaces 86 of the arms 66 to contact the snap ring 90 and move the snap ring 90 downwardly relative to the housing 38. The snap ring 90 is compressed radially inwardly as it moves axially through the inwardly tapered surface 82 of the housing 38. The inner press assembly 60 and snap ring 90 continue to move downwardly until the snap ring 90 is aligned with the snap ring groove 24 of the component 26 as shown in FIG. 6.

In FIGS. 6 and 7, the snap ring 90 is shown having expanded properly radially into the snap ring groove 24 of the component 26. The first end 68 of the arm 66, though biased radially outwardly is moved inwardly by the annular inward projection 81, such that the abutment surface 86 of the arm 66 is positioned radially inward of the snap ring 90 and the snap ring 90 is positioned in the notch 88 of the arm 66 as can be seen in FIG. 7. This figure shows a successful connection of the components 26 and 28.

Referring to FIGS. 8 and 9, if the snap ring 90 should fail to expand radially outwardly into the snap ring groove 24, the abutment surface 86 of the arm 66 will contact the snap ring 90 thereby resisting the downward motion of the inner press assembly 60. Upper press assembly 32 continues to move downwardly causing upward axial movement of the inner press assembly 60 relative to the upper press assembly 32 and compressing springs 62 (see FIG. 4). As can be seen in FIG. 8, the entire upper press assembly 32 has moved downwardly relative to the inner press assembly 60 approximately a distance equal to the depth of the notch 88 from the abutment surface 86.

As shown in FIG. 10A, when the inner press assembly 60 moves relative to the upper press assembly 32, the leg 52 of the lever 50 is driven upwardly. As a result, the finger 54 moves downwardly and switches the optical switch 56 to indicate that the snap ring is not properly installed in the snap ring groove 24. The optical switch 56 sends a signal to a controller 93 or other indicator.

In one embodiment, the lever 50 is formed with the hole 92. As shown in FIG. 10B, a light source 94 is aligned at one end of the hole 92, and other end of hole 92. The light source 94 can thus direct a beam through hole 92 to sensor 96 when lever 50 is at a to normal position. This provides a signal that the snap ring has been properly inserted. If light from source 94 does not reach sensor 96 at the end of a cycle of the machine, then a signal is sent that the snap ring was not properly inserted. An alarm of some sort may then be actuated to alert an operator. The details of the switch shown here are preferred, but other switches come within the scope of this invention. Of course, the light source and sensors could be arranged such that light would only reach the sensor when an improper connection has been made, rather than when a proper connection has been made.

Referring to FIG. 11, lever 50 pivots about a fulcom 58 between end 59 and leg 52. The spring 97 biases finger 54 upwardly to its normal position. Extension 53 includes a recess 57 into which one of source 94 or sensor 96 are normally inserted. In this way, it is ensured the two are aligned with hole 92. Normally, finger 54 of the lever is positioned such that hole 92 is aligned between the source 94 and sensor 96.

In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent a preferred embodiment. However, it should be understood that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.