Bell System Practices 37 Description

,1
•
BELL
SYSTEM
PRACTICES
AT&TCc, Standard
SECTION 574-320-101
Issue 2, February 1973
1.
2.
3.
4.
3 7 TYPING UNIT
3 7P003 AND UP
DESCRIPTION AND PRINCIPLES OF OPERATION
CONTENTS
PAGE
GENER.AL ................... 1
DESCRIPTION ....................
7
BASIC UNIT
.
. . .
.
.
. . .
.
.
. .
.
.
.
.
7
WIDE PLATEN
...............
8
CONTROL FUNCTIONS ..........
8
OPTIONAL FEATURES ..........
8
TECHNICAL DATA •••••••••••••
8
PRINCIPLES OF OPERATION
.....
12
A. Selector Mechanism •••.•.••
12
B. Transfer Mechanism .•••••••
24
c.
Codebar Shift Mechanism •.•••
25
D.
Codebar Mechanism ........
26
E. Codebar Positioning •.••••••
26
F.
Typebox and Typebox
Carriage ••••••••••••••••
28
G.
Horizontal Positioning •••••••
31
H.
Horizontal Dampener
Mechanism ..............
31
I. Vertical Positioning ••••.••• 34
J.
Vertical Dampening ••••••••
36
K.
Trip Shaft Mechanism •••.•••
37
L.
Print Hammer Carriage and
Printing Drive Mechanism ••••
40
M.
Spacing Mechanism ••••••••• 42
N.
Backspace Mechanism •••••••
42
o.
Retraction Mechanism •••••••
44
P. Function Box and Function
Box Drive Mechanism • • • • • • • 46
Q.
Ribbon Positioning
Mecha.nism .............. 48
R .
Ribbon Feeding and Reversing
Mechanism ..............
50
s.
Print, Space, and Function
Suppression . ............. 53
T.
Carriage Return Mechanism •••
54
u.
Line Feed Mechanism •••••••
54
v.
Vertical Tabulation
Mechanism ••••••••••••••
56
·5.
6.
CONTENTS
PAGE
w.
Horizontal Tabulation
Mechanism •••••••••••••• 57
x.
Half-Forward and Reverse
Line Feed ............... 58
Y .
Function Bar Coding
.
......
61
REFERENCES
.
..............
61
APPENDIX
.................
63
A. Printed Graphics Extension
(Shift-Out, Shift-In) . • • . . . . . 63
B. Visual Aid With Graphic
Extension . • . . . . . . . . . . . . . 64
C. Character Received Contact
Mechanism . . . • . . . . . . • . . . 64
1.
GENERAL
1. 01
This section. describes the late design
37 typing unit (Figure 1) and the wide
platen typing unit (Figure 11 ). This is a general
revision which includes all previously issued
supplementary information concerning the
description and principles of operation of the
Figure 1 - 37 Typing Unit With
Variable Features
Prepared for American Telephone and Telegraph Company by Teletype Corporation
©
1966, 1970, 1971, and 1:J72 by Teletype Corporation
All rights reserved
Printed
in U.S.A.
"Page 1