PRODUCT SELECTION BALL RETAINER
PRODUCT GUIDE BALL RETAINER
■ Movement of Ball Retainer
■ Ball Retainer Motion
Fig. Ⅰ shows travel distances of the ball retainer and bushing (ejector plate) when the ejector plate strokes from A to B. The ball retainer's travel distance is a half of the bushing's. The ball retainer is inserted between the pin and the bushing with preload applied. Rolling motion of the retainer's built–in balls reduce friction and eliminate possibilities of galling, enabling the ejector plate to stroke smoothly.
A
B
Ⅰ
Ⅲ . The ball retainer may hit the plate if the difference between S and E is too small.
Ⅰ . Mold closed with the ejector plate returned completely
Ⅱ . The ball retainer may come off if the difference between S and E is too large
Back up plate (retainer plate)
X: Travel of the ball retainer Y: Travel of the bushing (ejector plate) ※ X = 1 2 Y relative travelling distance. ■ How to Mount
Stopper pin
Upper ejector plate
Lower ejector plate Ejector leader bushing
Bottom clamping plate
Ⅳ
Ⅱ
Ⅲ
When L p ＜ 2L B + L 1 −5: The ball retainer protrudes from the pin when set.
When L p ≧ 2L B + L 1 –5: The ball retainer is in the pin.
The ball retainer's travel distance is a half of the bushing's. If the ball retainer's position is not correct, it may cause problems shown in Fig. ⅡⅢ above. To ensure the ball retainer's correct stroking movement, its length must be carefully selected. ■ Table Ⅰ : Ball Retainer Length Selection ※ T dimension is calculated in 4 ways as follows. ① Using a stopper pin or stopper ring (thickness: 5mm) … …… T = Thickness of the ejector plate (upper & lower) + 5mm ② Using a spacer (thickness: 4mm) …………………………… T = Thickness of the ejector plate (upper & lower) + 4mm ③ Combination of ① and ② (as in Fig Ⅰ ) … ………………… T = Thickness of the ejector plate (upper & lower) + 9mm ④ Ejector plate only (neither ① nor ② ) … …………………… T = Thickness of the ejector plate (upper & lower)
Back up plate (retainer plate)
Upper ejector plate
• Using a stopper pin or stopper ring • Using a spacer
Using a stopper pin or stopper ring
①
② Using a spacer
③
④ Ejector plate only
Method (pattern)
Lower ejector plate
Upper ejector plate thickness
13 15 15 20 25 13 15 15 20 25 13 15 15 20 25 13 15 15 20 25
T
Bottom clamping
L p + l 1 2
Lower ejector plate thickness
N = L B + L 1 –5
N =
15 15 20 25 30 15 15 20 25 30 15 15 20 25 30 15 15 20 25 30
–5
plate Stopper pin
Ejector leader bushing
35 (8)
35 (10)
35 (10)
35 (10)
50
35 35
– – 35 35
– –
– – – 35353535 –
60
40403535 – 40403535 – 35353535 – 4040404040
Mounting the ball retainer so that the bushing's lower end aligns with the ball retainer's lower end when the ejector plate is fully returned (the mold is closed) as shown in Fig. Ⅱ above. To achieve this, attach the ball retainer to the pin before inserting it into the bushing, and fix it at the N position shown in Fig. Ⅲ / Ⅳ using an O–ring. Then insert it into the bushing. Sliding the pin and bushing by the length of their engagement (C in Fig. Ⅲ and L B –2.5 in Fig. Ⅳ ) should make the lower ends of
70
45 45 40 40 40 45 45 40 40 40 40 40 40 40 40 45 45 45 45 45
Spacer block thickness
80
50 50 45 45 45 50 50 45 45 45 45 45 45 45 45 50 50 50 50 50
the both meet, leaving the specified L 1 length. ● To obtain N, calculation of l 1 is necessary. 1. l 1 calculation ① Using a stopper pin or … ……… L 1 = Thickness of the plate (upper & lower) + 5–Full length of the bushing stopper ring ② Using a spacer ………………… l 1 = Thickness of the plate (upper & lower) + 4–Full length of the bushing ③ Combination of ① and ②……… l 1 = Thickness of the plate (upper & lower) + 9–Full length of the bushing ④ Ejector plate only … …………… l 1 = Thickness of the plate (upper & lower)–Full length of the bushing (neither ① nor ② )
90
55 55 50 50 50 55 55 50 50 50 50 50 50 50 50 55 55 55 55 55
100
60 60 55 55 55 60 60 55 55 55 55 55 55 55 55 60 60 60 60 60
110
65 65 60 60 60 65 65 60 60 60 60 60 60 60 60 65 65 65 65 65
120
70 70 65 65 65 70 70 65 65 65 65 65 65 65 65 70 70 70 70 70
※ Values in ( ) signify the maximum strokes. These combinations make the ball retainer hit the backup plate (retainer plate) before the ejector plate as in the case of Fig. Ⅲ . These values in ( ) also signify the ejector plate's stroke when the ball retainer hits the backup plate. ※ Values not enclosed in ( ) signify combinations that allow the ejector plate to stroke until it hits the backup plate.
L p + l 1 2
(Fig. Ⅲ )
2. N calculation When L p ＜ 2L B + l 1 −5… …………… N =
–5
When L p ≧ 2L B + l 1 −5… …………… N = L p + l 1 –5 (Fig. Ⅳ ) ※ L p : Overall length of ejector guide pin (L p = Actual measured length of the pin for inlay style application) L B : Full length of the ball retainer
885
886
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