• U.L. listed assemblies - Nema 1 and Nema 12
under file E56660, Nema 9 under file E75487
Accessories
The following accessories can be obtained with
the GEMCO Rotating Cam Limit Switch:
• Straight Drive and Right Angle Gear
Reducers
• Timing Dial and Timing Dial Window
• Electrical Wiring per Customer’s Specification
• Motor Driven Rotating Cam Limit Switch with
AC or DC for Adjustable Speed Drives
• Potentiometer driven off the Camshaft
• Spring Return Mechanism
• Plug-In Socket
• Double Ended Shafts
• Pilot Lights
• 3 Way and 4 Way Air Valves directly
interchangeable with switches
• Special Conduit Opening
• Special shaft extensions and keyway
• Adjustable Coupling (See Catalog Section
3001)
• Special Cams & Large 6” Cams for Higher
Resolution
• Combination Adjustable-ln-Motion and MicroAdjust Circuits (see Catalog Section 1981)
• Electric Clutch and/or Brake
• Separate Terminal Strips
• Add-A-Cam Feature
• Factory Adjustment of Cams Available
• Open Type Units
• Dual Shafts
• Motion Detector *
• GEMCO DRIVE-CHEK® *
Either of the above is necessary for mechanical
press application
• Dual Shaft Cam Switch
Consult manufacturer for desired accessories
Applications
GEMCO’s all new Micro-Adjust Rotating Cam
Limit Switch is a pilot device used for heavy
duty material handling mechanisms, mechanical
presses,* packaging machines, rotary table, and in
many other applications where accurate, repetitive,
and sequential operations are required in control
circuitry.
When motion is expressed in shaft rotation, either
through a roller chain, gear train, or directly, the
GEMCO Rotating Cam Limit Switch makes it
possible to open or close independent circuits at
any desired angular position.
Mount the assembly and couple input shaft to the
driving member with the shaft keyway up and in line
with the positioning arrow on the bearing end plate.
The machine should be in the start cycle position.
Establishing Camshaft
Direction of Rotation
Cam settings should be made with the
Camshaft uppermost to the viewer. The picture
at the top right illustrates this viewing position
and also shows the adjusting tool being applied
to the adjusting wheel. Shaft rotation is always
established off the right end of the unit even
when the input shaft, whether direct or through
a gear reducer, is situated at the left end. As an
aid to designating shaft rotation when a gear
reducer is used, consult page 14 of this catalog
section.
Cam Settings
SWITCH SIDE
For clockwise rotation, set ‘’make’’ angle with
the black dial and ‘’break’’ with the red dial for
dwell settings less than 180°. Reverse colors for
dwells 180° or greater.
For counterclockwise rotation, set ‘’make’’ angle
with the white dial and ‘’break’’ with the yellow
dial. Reverse colors for dwells 180° or greater.
Switch connections should be made in
accordance with the illustrations to the right,
which incidentally are both clockwise rotating
examples.
Precision, rugged duty snap action switches,
extremely accurate cam adjustments with a heavy
duty shaft, rugged case and lifetime sealed ball
bearings, have been combined by GEMCO to
provide the most versatile and dependable Rotating
Cam Limit Switch available.
No Special Cams are Required
The accurate cam adjustments are made possible
by the use of a separate reduction drive in each half
of a circuit cam block assembly. This drive provides
a 36 to 1 ratio which means that one revolution of
the adjustment wheel will advance or retard the cam
setting by 10 degrees.
• The maximum temperature with full electrical load
is 185°F. The minimum operating temperature is 50°F minimum cam adjusting temperature is -10°F.
• Standard GEMCO Rotating Cam Limit Switches
have a rating of 50 pounds end thrust and 500
pounds radial load on standard shaft extensions.
• Torque Required - .6 lb. - In/Circuit.
• Repeatability +/- 1/4°
Snap Action Switches
All standard GEMCO Rotating Cam Limit Switches
employ SPDT precision type snap action switches
which provide the advantage of double-break
contacts and are actuated at a uniform rate to give
long life. DPDT switches can be provided upon
request. Any number of circuits from 1 to 40 may be
supplied as standard in Nema 1, Nema 4, Nema 7
and Nema 12 enclosures.
Each switch setting can be adjusted to your circuit
requirements. An unlimited selection of circuit
arrangements is available with the GEMCO Rotating
Cam Limit Switch, with no special mounting cams,
dogs, etc. for contact settings.
GEMCO Microadjust Cams Provide
Unlimited Circuit Versatility
For most applications, therefore, no special cams
are necessary and settings may be changed at any
angular position of the camshaft.
• Lifetime Sealed Ball Bearing allows mounting in
any position.
• Large Cover Openings for ease of wiring.
• No Minimum Speed is specified because snap
action contacts are used. Maximum rated speed
of the Camshaft is 500 RPM and can be rotated
either clockwise or counterclockwise.
• Two types of compact integrally
Reducers are available with ratios of 1:1 through
600:1. They can also be supplied with speed
multipliers up to 1:8.
The GEMCO Precision Snap Switches are designed
for industrial duty applications where compact
size, complete reliability and millions of trouble free
operations are required.
The housing is molded material which has excellent
resistance to arcing and carbon tracking. The
operating button is of molded nylon, a material with
excellent wear characteristics.
The button is well guided at the top and bottom to
insure accurate repeatability and minimum wear.
The switches are individually mounted and can be
readily replaced without the need of adjustment or
alignment. All switches have binder head terminal
screws which are accessible for wiring with either
stripped or wire lug connections.
Any combination of single-pole double-throw or
double-pole double-throw snap action switches can
be supplied with the GEMCO Rotating Cam Limit
Switch.
Electrical Contact Ratings
AC
Inductive Pilot Duty 35% Power FactorResistive 75% Power Factor Inductive Pilot Duty and Resistive
MakeBreak
Switch
ContactsVolts
Type
1950-4DPDT115
1950-1SPDT110
230
440
575
220
440
600
AmpsVAAmpsVA
30
15
7.5
6
40
20
10
8
3450
3450
3450
3450
--
--
--
--
3
1.5
0.75
0.6
15
10
6
5
345
345
345
345
--
--
--
--
Continuous Car
rying Amps
10
10
10
10
15
15
15
15
NOTE: Refer to Catalog Section 1950 for detailed
information pertaining to all Standard and Special
Switch Options.
The GEMCO Rotating Cam Limit Switch can be
supplied with the desired shaft extension. The
standard shaft extension can be specified in the
catalog numbering system on page 8.
To determine the shaft extension symbol, the
Rotating Cam Limit Switch must be viewed from the
switch side of the assembly as shown. The shaft
extension can be specified as either:
L = Left shaft extension
R = Right shaft extension
D = Double shaft extension (both ends)
X = No shaft extension opposite the gear box
Y = Shaft extension opposite gear box
Switch Type
The GEMCO Precision Snap Switches are specifically designed for industrial duty applications where
reliability, ease of wiring and millions of trouble free
cycles are required.
The GEMCO Rotating Cam Limit Switch can be
supplied with either a basic single-pole double-throw
(SPDT), double-pole double-throw (DPDT), or a
combination of both types.
A plug-In socket can be supplied with either the
SPDT or DPDT switches.
NOTE: Call Sales at 1-800-635-0289 for information
about 1950 Snap Switch parts and options.
The type of snap switch can be specified in the
catalog numbering system on page 8.
SP = Single-pole double-throw
DP = Double-pole double throw
SPP = Single-pole double-throw with a plug-in
socket
DPP = Double-pole throw with a plug-in socket
The Plug-In Socket eliminates error due to disconnecting and connecting wires during replacement
of the snap switch. A marking strip is supplied with
each plug-in socket for ease of wire identification.
Switch Replacement is Recommended Every
15 Million Cycles.
Part No. SD-1178-C
(includes two cams Part Nos. P-356-B and P-357-B)
Blank Cam Assembly
Part No. SD-1140-C
(includes two blank cams Part No. P-271-B)
Special Cams
A Blank Cam Assembly (Part No. SD-1140-C) can
be supplied in place of the Standard Cam Assembly,
(Part No. SD-1178-C) at no additional charge, when
specified. Advise number required and location.
A drawing of the Cam shape must be given
with the order. Generally, two cams are required
per circuit. When ordering special cut cams, the
customer will supply a detail of the cam profile and
the electrical timing chart showing the contact
setting as required.
Description
The DRIVE-CHEK is a multi-purpose sub base that
is mounted under a chain or belt driven mechanism.
The unit serves three purposes; a broken chain or
belt detector, a chain or belt tightener, and a shock
and vibration isolator.
A GEMCO Indicator Switch is provided with each
DRIVE-CHEK Unit to indicate when a drive belt or
chain failure has occurred. Shock and vibration from
the machine to the hinge plate of the DRIVE-CHEK
Unit are dampened by coil springs on one end of the
hinge plate and an elastomeric support on the other
end.
the drive belt or chain. DRIVE-CHEK is of rugged
welded construction and is painted to prevent
corrosion. The drive chain or belt can be attached to
the mechanism being driven from either above or
below the DRIVE-CHEK base.
The DRIVE-CHEK base can be purchased as
a separate item for field mounting or factory
assembled to the 1980 camswitch. If factory
installation is desired, order as separate item and
specify as being assembled in the description.
A GEMCO single-pole double-throw switch with
mounting plate is supplied with each DRIVE-CHEK
Unit and can be easily mounted inside the GEMCO
Rotating Cam Limit Switch enclosure. A GEMCO
double-pole double-throw switch can also be
supplied.
11
B
.34
#606 WOODRUFF KEY
GROOVES TO ACCEPT
GEMCO ADJ. COUPLING
(4 MTG HOLES)
7.94
MIN. VERTICAL
CLEARANCE TO
REMOVE COVER
NOTE:
ASSEMBLY SHOWN IS STANDARD.
SHAFT EXTENSIONS CAN BE PLACED AT
EITHER END OR BOTH ENDS.
E
1.88
4.05
1.50
.7490
.7475
.75
.12
L
AT SHAFT END
(2) HOLES, PLUGGED
CONDUIT SIZE
2.07
A
3.18
D
C
.75
Dia.
Dia.
NEMA 1 Dimensions
No. of CircuitsAA-SA-RBCDELWt. Approx. Gross
2 to 49.2812.129.384.426.505.003.12.7512 lb.
5 to 611.7214.5611.826.866.505.003.121.2514 lb.
7 to 814.1617.0014.269.306.505.003.121.2516 lb.
9 to 1219.0421.8819.1414.186.505.003.121.2521 lb.
13 to 1625.4528.2925.5520.607.005.503.402.0035 lb.
17 to 2030.3333.1730.4325.487.005.503.402.0046 lb.
21 to 2435.2138.0535.3130.367.005.503.402.0055 lb.