Heat shield for a starter solenoid

A heat shield for shielding the solenoid of an engine starter from heat generated by an internal combustion engine. The shield is formed of metal and has a first pair of deflectable spring arms for securing the heat shield to a solenoid of an engine starter. The arms have arcuate portions that are adapted to engage the case of the solenoid and the arms are deflected apart when the shield is assembled to the solenoid. The arms then spring back toward each other to tightly grip the solenoid. The heat shield has another pair of deflectable arms the end portions of which are adapted to engage fasteners that secure the shield to the drive housing of an engine starter. The heat shield has a deflectable spring finger that is adapted to engage the solenoid to prevent vibration of the heat shield.

This invention relates to a heat shield for the solenoid of an electric 
engine starter for shielding the solenoid from heat generated by an 
internal combustion engine. 
When an engine starter is mounted on an internal combustion engine in such 
a position that the starter solenoid is located near the exhaust manifold 
of the engine, the solenoid is exposed to extreme temperatures. If the 
solenoid is not heat shielded, the solenoid may be heat damaged and the 
solenoid performance is reduced due to an increase in solenoid coil 
electrical resistance caused by the elevated temperature. 
It is an object of this invention to provide a heat shield arrangement for 
a starter solenoid that does not use threaded fasteners for securing the 
heat shield to the starter. Thus, a heat shield made in accordance with 
this invention can be snapped onto the starter solenoid. More 
specifically, the heat shield of this invention is formed of spring steel 
material that has a pair of spring arms or legs that can be sprung apart 
to assemble the heat shield to the starter solenoid. These arms in the 
assembled position of the heat shield tightly engage opposed surfaces of 
the solenoid. The heat shield further has a spring finger or leg which in 
the assembled position of the heat shield engages an outer surface of the 
solenoid. In addition to the foregoing, the heat shield is provided with a 
pair of anti-turn arms or legs. These anti-turn arms or legs have end 
portions that engage the inside of fasteners that are used to secure the 
solenoid to a starter drive housing. In addition, the anti-turn arms are 
located between flanges that are respectively on the solenoid and drive 
housing to prevent the heat shield from moving axially relative to the 
solenoid.

DETAILED DESCRIPTION OF THE DRAWINGS 
Referring now to the drawings and more particularly to FIG. 1, a portion of 
an electric engine starter is illustrated. This engine starter has a drive 
housing 10 which contains a shift lever (not illustrated) that operates to 
move a pinion (not illustrated) into and out of mesh with the ring gear of 
an engine. The drive housing 10 has a radially extending flange 12 
provided with opposed threaded bosses 14 and 15. The flange 12 has a 
surface 16 that faces a starter solenoid. 
The engine starter has a solenoid generally designated as 18. The solenoid 
has an outer metallic case 20 that has an outer circular configuration. 
The solenoid further has an end cap 22 that is formed of electrical 
insulating material that supports terminals. The case 20 encloses a 
pull-in coil winding and a hold-in coil winding (not illustrated). These 
windings cooperate in a known manner with a solenoid plunger or armature 
(not illustrated) that has one end connected to the starter shift lever in 
a known manner. 
The case 20 of solenoid 18 has two integral opposed radially extending 
flanges. One of these two flanges is shown in FIGS. 1 and 2 where it is 
designated as 24. The flange 24 has a surface 25 which faces the surface 
16 of flange 12. Flange 24 has a semicircular groove or slot 26. A 
threaded fastener 28 is provided for securing solenoid 18 to drive housing 
10. This fastener is shown in FIG. 2. The fastener 28 has a threaded 
portion 30 that is threaded into boss 14 on drive housing 10. The fastener 
28 has a head 32 that engages a surface portion of flange 24. A portion of 
fastener 28 extends through the semicircular groove 26. 
Another threaded fastener 34 is provided for securing the solenoid 18 to 
drive housing 10. The fastener 34 is identical to fastener 28 and it 
cooperates with a radially extending flange (not illustrated) that is 
identical to flange 24 and which is located opposite to flange 24. The 
fastener 34 has a threaded portion that is threaded into boss 15. 
Referring now to FIG. 3, a heat shield made in accordance with this 
invention is illustrated. The heat shield is generally designated as 36. 
The heat shield 36 is formed of a heat treated spring steel material that 
may be about 1.0 mm. thick. 
The heat shield 36 has a main axially extending heat shield portion 38. The 
portion 38 carries a pair of resilient spring arms 40 and 42 that are 
integral with portion 38. Arm 40 has a semicircular or arcuate portion 44 
and a folded-over portion 46. Arm 42 has a semicircular or arcuate portion 
48 and a folded-over portion 50. 
The heat shield 36 further has a central depending resilient spring finger 
52 that is integral with heat shield portion 38. The end portion 53 of 
spring finger 52 has a curved shape. 
The heat shield 36 also has a pair of opposed resilient spring finger arms 
54 and 56 that are integral with portion 38 and which are located adjacent 
one end of the heat shield. Arm 54 is comprised of a straight portion 58 
and an arcuate or curved portion 60. In a similar fashion, arm 56 has a 
straight portion 62 and an arcuate or curved portion 64. 
FIGS. 1 and 2 show the heat shield 36 assembled to the engine starter and 
the manner in which this is accomplished will now be described. 
To assemble heat shield 36 to the starter, the arms 54 and 56 are aligned 
with the gaps between the surface 16 and the surfaces on the flanges of 
the case 20, like surface 25. The width of arms 54 and 56 is slightly less 
than the gap between the flanges, for example, the gap between flange 
surfaces 16 and 25. The arms are inserted into the just described gaps and 
through the spaces between a fastener, like fastener 34, and an outer 
surface of solenoid case 20. In the final assembled position of the arms 
54 and 56, the arcuate portions 60 and 64 engage cylindrical surface 
portions of fasteners 28 and 34, as shown in FIG. 2. At the time that the 
arms 54 and 56 are being inserted into the gaps, the spring arms 42 and 44 
are pushed onto the solenoid case 20 where they are forced apart by the 
solenoid case. The arms then spring back to a final assembled position 
where the inner surfaces of arcuate portions 44 and 48 engage the outer 
arcuate surface portions of case 20, as shown in FIG. 2. When the heat 
shield 36 is assembled, the end 53 of spring finger 52 engages an outer 
surface of case 20 and spring finger 52 is slightly deflected. 
In the final assembled position of heat shield 36, the distance between 
arms 40 and 42 is greater than the distance between these arms prior to 
assembly. Thus, the diameter of case 20 is such that the arms 40 and 42 
are deflected away from each other when they are assembled to case 20. The 
arms spring back thereby producing a spring-like force that maintains the 
arms in tight engagement with the case of the solenoid. 
In the final assembled position of heat shield 36, the distance between the 
ends of arms 54 and 56 is less than the distance between the ends of these 
arms prior to assembly. Thus, as arms 54 and 56 are assembled to the 
solenoid, they are moved toward each other and then spring apart to a 
position where the end portions 60 and 64 respectively engage portions of 
the fasteners 28 and 34. 
When heat shield 36 is assembled to the solenoid 18, the curved portion 53 
of spring finger 52 engages the case 20 of the solenoid and the spring 
finger 52 is deflected. The spring force developed by the deflected spring 
finger 52 prevents vibration of the heat shield. It also develops a force 
tending to move heat shield 36 away from case 20. This force tends to 
cause the curved portions 60 and 64 of arms 54 and 56 to pull into tight 
contact with the fasteners and applies a force to arms 40 and 44 causing 
portions of these arms to be maintained in tight engagement with the 
solenoid case 20. 
The arms 54 and 56 tend to prevent turning or rotation of the shield 36 
relative to the solenoid. They also prevent axial movement of the heat 
shield relative to the solenoid. Thus, arms 54 and 56 are located in gaps 
between flange surface 16 and the flange surfaces like flange 25 or flange 
24. 
Arms 40 and 42 form the primary support for the heat shield. 
Spring finger 52 operates to prevent vibration of the heat shield and 
develops a spring force that biases or tends to move the heat shield away 
from the solenoid. 
In the final assembled position of the heat shield 36, as shown in FIG. 1, 
the heat shield portion 38 extends for the entire length of solenoid 18. 
More specifically, the heat shield portion 38 extends axially from surface 
16 of flange 12 to a point beyond the other end of the solenoid. The 
starter is mounted on an engine in such a position that the heat shield 
portion 38 of heat shield 36 is located between the exhaust manifold of 
the engine and the solenoid. It, therefore, shields the solenoid from heat 
generated by the engine.