Method of forming an annular slot in a longitudinally splined annular member

Lanced slots are formed in the root section of each spline of a splined member to receive a snap ring for securing discs or other members in position with respect to the splined member.

BACKGROUND OF THE INVENTION 
I. Field of the Invention 
The present invention relates to splined members and more particularly to 
the construction of a slot in such members to receive a snap-type 
retaining ring. 
II. Description of the Prior Art 
It is conventional practice to form slots in splined clutch housings or 
brake drums or the like to receive snap type retaining rings for the 
purpose of retaining clutch or brake plates with respect to the splined 
housings or drums. However, such means as have been heretofore employed 
have utilized machining or other operations which are quite costly and 
which require deburring or special design concessions to the snap ring. 
SUMMARY OF THE PRESENT INVENTION 
The present invention overcomes the problems associated with previous 
methods of providing a slot in splined members for receiving a snap type 
retaining ring. Rather than machining the slots and thereby requiring 
deburring, the slot is formed by providing a series of individual lances 
in the root section of each spline. 
In this way, rather than removing material to thereby weaken the part as 
well as requiring further machining, such as deburring, the material is 
merely displaced. 
While lancing of course is not new, utilizing such means to form the slot 
for receiving a retainer ring in a splined member overcomes serious 
problems associated with previously used methods for forming such slots.

Description of Several Preferred Embodiments of the Present Invention 
Now referring to the drawings, FIG. 1 illustrates one assembly in which the 
present invention can be used. It is to be understood, however, that it is 
not intended to limit the invention to the use illustrated in FIG. 1. 
FIG. 1 shows a portion of an automatic transmission for an automobile or 
the like as an example of a use of the present invention. The automatic 
transmission includes a splined clutch housing 12 fixed to a shaft 14 and 
rotatable therewith. A plurality of clutch plates 16 are trapped within 
the housing 12 by the splines thereof so that rotation of the shaft 14 
produces rotation of the clutch housing 12 and the clutch plates 16 
carried thereby. 
A housing member 20 is also a splined clutch housing and clutch plates 18 
are trapped by the splines formed about the outer periphery of the clutch 
housing 20. The housing 20 is fixed to a shaft (not shown). The clutch 
plates 18 are disposed intermediate and in frictional engagement with the 
clutch plates 18 so that power from the shaft 14 is transmitted through 
the clutch plates 16 and 18 to the housing member 20. A snap ring 22 fits 
in a slot 24 in a manner which will be described in greater detail 
hereinafter to prevent axial separation of the clutch plates 16 and 18 
with respect to the housing 12 and the member 20. 
The right hand section of the automatic transmission shown in FIG. 1 is 
similarly assembled and includes an externally splined clutch housing 30 
which is fixed to the member 12 so that the housing 30 is rotatable with 
the shaft 14. Clutch plates 38 are trapped by the splines on the outer 
periphery of the housing 30 and thus rotate with the housing 30. Clutch 
plates 36 engage with the clutch plates 38 and are trapped within a 
splined clutch housing 40 so that power is transmitted from the shaft 14 
through the members 12 and 30 and through the clutch plates 36 and 38 to 
the member 40. The member 40 is connected to other portions (not shown) of 
the transmission. 
A retainer ring 32 carried in a slot 34 prevents axial separation of the 
clutch plates 36 and 38 with respect to the housings 30 and 40. 
It is an improved means of forming the slots 24 and 34 that this particular 
invention is directed to. While such slots are utilized to hold snap-type 
retainer rings in splined clutch housings it is to be understood that such 
slots are also used to receive snap-type retainer rings in splined brake 
housings to thereby retain brake discs within the housings. The present 
invention contemplates a new means for forming such slots regardless of 
the use of the splined member and this should be kept in mind as the 
description proceeds. 
In FIGS. 2-5 a splined member 50 similar to the splined members 12, 20, 30 
and 40, is illustrated as having an inner peripheral slot 52 formed near 
the upper edge thereof for receiving a snap-type retaining ring 54. The 
slot 52 and the ring 54 correspond to the slots 24, 34 and rings 22, 32, 
respectively, shown in FIG. 1. 
As can best be seen in FIGS. 2 and 5 the slot 52 is formed by a series of 
pairs of parallel, individual lances 55 in the root section 56 of each 
spline. The material 58 between the lanced portions 55 is then displaced 
radially outwardly to form the internal slot 52 in the assembly of FIGS. 
2-5. 
As can best be seen in FIG. 6 the material 60 between the lanced portions 
can also be displaced radially inwardly to form an external slot 62 to 
receive an externally mounted retaining ring 64. 
It is apparent that the slots 52, 62 have been formed by a method which 
does not result in loss of material and thereby loss of strength. The 
material is simply displaced to form the slot. This also substantially 
reduces machining costs and makes it unnecessary to debur as is necessary 
when cutting or grinding operations are utilized to form the slot. 
It is apparent that although several embodiments of the present invention 
have been disclosed many other changes and modifications can be made 
without departing from the spirit of the invention or the scope of the 
appended claims.