Battery cable termination

A battery cable terminal for connecting a cable to a post of a battery. The terminal includes a metallic contact element having a ferrule for receiving an end of the cable and further has a contact portion for engaging the post. The terminal also includes a resilient, one-piece plastic clamp having a pair of arms defining an opening of receiving the post. The clamp holds the element so that the contact portion engages the post when the post is received by the clamp. The arms having facing distal ends defining a constricted throat for the opening with the facing end of each arm having a bearing surface so that the facing ends can be pried apart to increase the size of the opening. The clamp is spreadable from an as-formed condition in which the opening with the clamp holding the element has a dimension less than a corresponding dimension of the post, to a spread condition wherein the dimension of the opening is greater than the corresponding dimension of the post. In the spread condition, the clamp can be inserted over the post without substantial interference. The clamp returns towards its as-formed condition to firmly hold the post upon release of the clamp from its spread condition.

The subject invention relates to electrical terminations and, more 
specifically, to a cable termination for a vehicle battery and which does 
not require a fastener. 
BACKGROUND OF THE INVENTION 
Electrical cables connected to the electrical system of a vehicle are 
typically joined to the battery posts using yoke-shaped terminals, the 
free ends of which are drawn together using a fastener such as a nut and 
bolt. While initial tightening of the fastener results in a snug, low 
resistance termination, with time the material of the post undergoes a 
change of shape due to cold flow or creep. The terminal is unable to 
maintain compression and the post moves out of substantially full surface 
contact with the terminal. This results in a high resistance contact and, 
due to the high amperage drawn during engine starting, the terminal can 
become hot and, in an extreme situation, partially melt. A loose fitting 
terminal also undergoes increased oxidation. 
Sealed battery terminations are known in which a plastic cover is molded 
over a terminal plate. The battery has a lug with an internal thread and a 
cap nut must be threaded into the lug to hold the plate. The cap nut is 
unable to maintain compression in the event of cold flow of the lug 
material. For further information regarding the structure and operation of 
this prior art termination, reference may be made to U.S. Pat. Nos. 
3,928,974; 4,288,504 and 4,483,910. 
It is also known to provide a multi-piece termination in which metallic 
components for engaging the post are pivotally connected to a yoke of 
spring material. A screwdriver is used to bear against the post to spread 
the yoke so that the terminal can be pulled over the post. For further 
information regarding the structure and operation of this battery terminal 
clamp, reference may be made to U.S. Pat. No. 1,995,182. 
SUMMARY OF THE INVENTION 
Among the several aspects and features of the subject invention may be 
noted the provision of an improved battery cable terminal. The terminal is 
of one-piece construction in that a plastic clamp is molded about a 
metallic terminal element. The terminal of the present invention avoids 
the use of a separate fastener and functions to maintain compression on 
the post even in the event of cold flow of the post material. The terminal 
can be quickly mounted on and dismounted from the post without damage to 
the post because the post is not engaged by the tool used to spread the 
clamp. The terminal of the present invention is reliable in use, has long 
service life and is relatively easy and economical to manufacture. Other 
aspects and features of the present invention will be, in part, apparent 
and, in part, pointed out specifically in the following specification and 
in the accompanying drawings. 
Briefly, the battery cable terminal of the present invention includes a 
metallic contact element and a resilient, one-piece plastic split clamp 
having a collar holding the element. The element includes a ferrule for 
receiving one end of the cable and further has a contact portion for 
engaging the battery post. The clamp has a pair of arms at least partially 
defining an opening for receiving the post. The clamp holds the element so 
that the contact portion engages the post when the post is received by the 
clamp. The arms have facing distal ends defining a constricted throat for 
the opening with the facing end of each arm having a bearing surface so 
that the facing ends can be pried apart to increase the size of the 
opening. In the spread condition of the clamp, the clamp can be inserted 
over the post without substantial interference. Upon release of the clamp 
from its spread condition, the clamp returns towards its as-formed 
condition to firmly hold the post.

Corresponding reference characters indicate corresponding components 
throughout the several views of the drawings. 
DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, battery cable terminals for mechanically and 
electrically connecting electrical cables 22 to the generally cylindrical 
posts 24 of a vehicle battery 26 (shown in FIG. 1), are generally 
indicated by reference numeral 20. Each terminal 20 includes a metallic 
contact element 28 and a resilient plastic clamp 30 having a collar 32 
which is molded about a part of the element 28 so that the terminal is a 
single piece. The clamp is in the form of a split ring made up of two arms 
35, 36 defining an opening 37. The arms can be pried apart to spread the 
clamp to receive a post 24. It is common for the positive post to have a 
slightly larger diameter than the negative post. As the clamp is 
spreadable and resilient, a single size of the terminal 20 can be used for 
both the positive and negative posts. 
The element 28, best shown in FIGS. 2 and 3, includes a ferrule 38 for 
receiving an end 40 of the cable 22 from which the insulation has been 
stripped to expose the conductors 42. The element also includes a contact 
portion 44 connected to the ferrule by a neck 46 of reduced diameter. The 
contact portion is preferably in the form of an arcuate plate and has a 
shape similar to the outside surface of a post 24 to enter into generally 
full surface contact with the post thereby establishing a low resistance 
electrical connection. The element 28 can be formed of lead and can be die 
cast over the stripped cable end 40. Alternatively, the element 28 can be 
formed from a metallic blank made of a material such as brass or stainless 
steel which is stamped, folded and rolled to define the various components 
of the element. The ferrule formed from the blank can be crimped by 
rolling about the cable end 40 or a tube lug may be provided in the 
ferrule and a round crimp employed. 
The clamp 30 and collar 32 are molded of a suitable thermoplastic or 
thermosetting plastic with the collar 32 being molded about the neck 46 of 
the element. The contact portion 44 is disposed preferably in a recess 48 
formed by the inside surface of the clamp. The arms 34, 36 forming the 
split ring of the clamp have distal ends 50, 52, respectively, which can 
be pried apart to increase the diameter of the opening 37 in the clamp. 
More specifically, each distal end has a lip 56, 58, respectively, having a 
facing bearing surface 60. The lips extend generally in spaced parallel 
relationship outwardly from the opening 37 and define a constricted throat 
62 for the opening 37. FIG. 6 shows the clamp in its as-formed condition 
wherein the diameter of the opening 37, defined by the arms 34, 36 and the 
contact portion 44, is less than the outside diameter of either battery 
post 24. By inserting a simple hand tool, such as a screwdriver, between 
the lips 56, 58, the tool can be used to spread the arms 34, 36 
sufficiently to increase the size of the opening 37 to receive the post 
without interference from the post as shown in FIG. 7. The arms and collar 
are preferably molded from an engineering thermoplastic resin such as 
Torlon, a registered trademark of Amoco Chemicals, Celanex, a registered 
trademark of the Celenese Corporation, or Ultem, a registered trademark of 
General Electric. A fiber reinforced polymeric compound can also be used 
for the arms and collar. 
The arm 34 is shorter than arm 36 and is relatively rigid with a fillet 64 
interconnecting the collar and the arm 34. Thus, the axis of the 
constricted throat extends transversely to the axis of the collar 32 and 
preferably is at a right angle thereto. The longer arm 36 preferably has a 
decreasing thickness from its connected end (at the collar 32) to its 
distal end 52. This allows increasing flexibility away from its connected 
end so that the application of spreading forces causes the longer arm 36 
effectively to "unwind" to permit reception of the post 24. Upon release 
of the arms 34, 36, forces are applied to the captured post 24 by the arm 
36 pushing the post against the surface of the contact portion 44 of the 
element 28 resulting in a low resistance, substantially full surface 
engagement. This engagement is maintained by the application of 
compressive force by the arms even with cold flow or creep of the post 
material. 
Preferably, a strengthening rib 66 is provided on the outside surface of 
the arm 36. The rib is substantially centrally located and preferably is 
undulating. The rib provides increased stiffness without a generally 
thickening of the arm 36. When the arms are spread, the outside surface of 
the rib 36 goes into compression. The use of the undulating rib offers 
advantages over a straight rib because with the undulating rib, there is 
sideways deflection of the rib. This results in an increase in the elastic 
limit of the undulating rib 36 compared to a straight rib to provide 
increased strength of the clamp 30 without exceeding its elastic limit. 
Operation of the battery cable terminal 20 of the present invention is as 
follows: Referring to FIG. 6, the clamp is shown in its as-formed 
condition wherein a dimension of the opening 37 is smaller than a 
corresponding dimension of the post 24 to be received. In the case of a 
cylindrical post and a generally circular opening, the diameter of the 
opening is smaller than the outside diameter of the post. Referring to 
FIG. 7, the blade 68 of a screwdriver can be inserted between the lips 56 
and 58 and by using the screwdriver as a lever contacting the bearing 
surfaces 60, the arms 34, 36 of the clamp 30 can be spread causing the 
size of the opening 37 to increase sufficiently that the clamp can be 
placed over the post without substantial interference from the post. Upon 
release of the arms 34, 36, due to their resiliency, the clamp 30 firmly 
holds the post 24 against the contact portion 44 of the metallic terminal 
element 28. 
Unlike conventional battery cable terminals employing threaded fasteners, 
the battery cable terminal 20 of the present invention applies compressive 
forces to the post even after the post has undergone a slight change of 
shape due to cold flow of the material of the post. This results in a long 
service life, low resistance, reliable connection. Additionally, the clamp 
can easily be spread by reversing the above-described mounting procedure 
to achieve fast and simple dismounting of the terminal. This is very 
convenient when the battery 26 requires replacement. 
It will be appreciated that the collar 32 and the ferrule 38 have 
substantially the same dimensions so that the ferrule metallic material is 
exposed. Alternatively, the ferrule 38 could have larger or smaller 
dimensions as long as not insulated by a plastic covering. This provides a 
convenient location for connection of a jumper cable should jump starting 
of the battery be needed. 
In view of the above, it will be seen that the several objects of the 
invention are achieved and other advantageous results attained. 
As various changes could be made in the above constructions without 
departing from the scope of the invention, it is intended that all matter 
contained in the above description or shown in the accompanying drawings 
shall be interpreted as illustrative and not in a limiting sense.