Tog′gle-press.
One in which the platen is moved by the flexion or extension of two bars which unite to form a knee-joint.
This form of press has especial value for many purposes, as the motion of the platen is more rapid at the time when the toggle-bars are starting from the point of their greatest flexion, and, as they straighten out, the power increases and rate diminishes as the point of ultimate pressure on the bale is approached.
1. (
Printing.)
a. A form of press which succeeded the screw used universally until late in the eighteenth century.
One of the most familiar forms of this order of presses is to be found in the Stanhope
printing-press, in which the platen is depressed by a toggle and raised by springs.
The movement is variously known as a
knuckle, knee, or
elbow movement.
See Stanhope
printing-press, page 1796.
b. A press for making electrotype molds from forms of type.
The platen
a has a projecting table upon which the form and mold are adjusted to each other, and being pushed beneath the fixed head
b the platen is raised and the impression made by two pairs of toggle-jointed leaves
c c′ operated by a screw and crank wheel
d,
 |
|
Toggle-press. |
2. (
Baling) A cotton or hay press operating by the action of a toggle-joint.
The mode of presentation of the toggle varies, as will be seen in the following examples:—
 |
|
Toggle-press. |
In that shown (
Fig. 6500), the two toggles
a b are pivoted to a cross-head
c at their lower extremities; two oppositely threaded screws
d e work through corresponding hollow screws at the joints of the toggles, and are turned by a handwheel, causing them to approach or recede from each other and raise or lower the cross-head
c, to which the stem of the follower
f is connected.
If greater power be desired, it is obtained by using the lever
g, which turns the screws through the medium of a pawl and ratchet-wheel.
In another form, the two members of the toggle
H H are knuckled into the follower, which, in the illustration, receives motion from two levers which rest by their moving fulcrum rollers on a horizontal beam.
The motive cord is passed around pulleys in the lower ends of the levers.
 |
|
Toggle-press. |
 |
|
Overhead toggle-press. |
The conditions of this press are the inversion of those of the last.
In the former, power on the knee separated the hip and ankle, if the parallel may be allowed, as it may; in the latter case (
Fig. 6501), the hip and ankle are drawn together by the rope and pulleys, and the knee with its follower
G is elevated.
The illustration, Fig 6501, is that of a
[
2587]
beater-press, in which the upper weighted follower
I is dropped repeatedly upon the stuff in the box, until a certain degree of compactness is attained.
Then, the follower
I being locked in its down position, the bale receives its ultimate pressure from the ascending follower
G, operated by the toggle
H H, through the medium of pulleys
c, rope, and winding-shaft
D. See also beater-press; baling-press.
In another form (
Fig. 6502), the platen
E is raised by suspension rods
M M dependent from the ends of levers
I I which are constituted toggles by means of the rolling fulcrums
L L which are hinged to the frame.
They are operated by chains which pass around rollers at their lower ends and others in the frame.
 |
|
Toggle-press. |
In
Fig. 6503, the toggle-levers
C C are operated by cords serving to depress the slide
D to which the platen-rod
E is attached.
The follower
G has a long stem
E, by means of which it may be raised when used as a beater.
When the beating operation has progressed as far as desirable, the platen-rod
E is attached to the slide
D by a pin, and the toggles are brought into requisition to complete the baling.
In still another form (
Fig. 6504), the toggle is double acting, pressing upon two followers
a a which act within their respective boxes.
The action is simultaneous in the boxes.
Each toggle consists of a main beam
b and a rolling fulcrum
c; the adjacent ends of the beams
b b are simultaneously depressed by the rope which is rove through the pulleys on the levers and the standard
d respectively.
