US3139491A

US3139491A - Electric switch having selectively latched manually movable member

Info

Publication number: US3139491A
Application number: US24460A
Authority: US
Inventors: Hallis N Stephan
Original assignee: New Britain Machine Co
Current assignee: New Britain Machine Co
Priority date: 1954-03-12
Filing date: 1960-04-25
Publication date: 1964-06-30
Anticipated expiration: 1981-06-30

Description

June 30, 1964 H. N. STEPHAN 3,139,491 ELECTRIC SWITCH HAVING SELECTIVELY LATCHED MANUALLY MOVABLE MEMBER Original Filed March 12, 19 3 Sheets-Sheet l INVENTOR.

HALL/.5 N g N M ma a ATTORNE June 30, 1964 H. N. STEPHAN 3,139,491

ELECTRIC SWITCH HAVING SELECTIVELY LATCHED MANUALLY MOVABLE MEMBER Original Filed March 12, 1954 3 Sheets-Sheet 2 INVENTOR.

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June 30, 1964 H. N. STEPHAN ELECTRIC SWITCH 3,139,491 HAVING SELECTIVELY LATCHED MOVABLE MEMBER MANUALLY Original Filed March 12, 1954 3 Sheets-Sheet 3 INVENTOR. HALL/.s/YSre-PHA BY 1954. Divided and this application Apr. 25, 196i}, Ser.

Claims. (Cl. 20045 The present invention vrelates to the manual control of power actuated apparatus under the visual supervision of an operator, such as, power driven machine tool slides, spindles, etc., and to devices for controlling power actu ated visually supervised operations. This application is a division of my co-pending applicationSerial No. 772,494, filed November 7, 1958, which application is a continuation of my application Serial No. 415,870, filed March 12, 1954, now both abandoned.

The principal object of the present invention is the provision of a novel and improved manual control, especially adapted for controlling the actuationof a power driven apparatus under visual supervision, comprising a member supported for manual movement in a plane from a first position to which it is spring or otherwise biased to a secondposition at one side of the first and for oscillation about an axis parallel with the aforementioned plane when in the second position to selectively latch and unlatch the member in the second position in combination with a power control instrumentality operatively associated therewith in such a manner that the power drive is inoperative when the member is in the first position and is operative when the member is in the second position.

A still further object of the invention is the provision of a new and novel manual operated electric switch means, especially suited for operating a power actuated device under the visual supervision of the operator, comprising a manually movable member supported for manual movement in a plane from a first position to which it is spring or otherwise biased to a second position at one side of the first and for oscillation about an axis parallel with the aforementioned plane when in the second position to selectively latch and unlatch the member in the second position and an electric. switch operatively associated therewith in such a manner that it is in inoperative position when the member is in the first position and in operative position when the member is in the second position.

The invention resides in certain constructions and combinations and arrangements of parts and further objects and advantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment described with reference to the accompanying drawings forming a part of this specification, in which similar reference characters designate corresponding parts, and in which:

FIG. 1 is a. perspective view of a combined horizontal boring, drilling and milling machine embodying the present invention;

FIG. 2 is an enlarged perspective view of the pendant control station;

FIG. 3 is a sectional view taken approximately along line 33 of FIG. 2 showing the switch structure used with a pendant control station;

I United States Patent '0 of the operator.

3,139,4hl Patented June 30, 1964 FIG. 4 is a sectional view taken approximatelyalong line 4-4 of FIG. 3; 7

FIG. 5 is a sectional view taken approximately along line 55 of FIG. 3; and

FIG. 6 is an enlargerd view of the cam shown in FIG. 5.

The present invention is susceptible of various modifications and uses but it is particularly suitable for use with a machine or other device where it is necessary or desirable to perform one or a plurality of operations under the visual control or supervision of an operator, from a single control station, such as, a combined horizontal boring, drilling and milling machine wherein a plurality of movable machine tool elements are to be moved or otherwise operated from a single station under visual supervision The invention is herein shown as embodied in a combined horizontal boring, drilling and milling machine of the type illustrated in United States Patent No. 2,339,435.

Referring to the drawings, the machine shown therein comprises a base A, provided at one end with a spindle head column B formed with vertical ways 10 and 11 upon which a spindle head C is mounted for vertical movement, and at the other end with a backrest or outboard support column D slidably supported on two or more horizontal ways 12 formed on the upper side of the bed. The ways 12 also support a saddle E having transverse horizontal ways 14 and 15 on the upper side which in turn support a work table F. The backrest column D is provided with vertical ways upon which a backrest block G is mounted for vertical movement.

The spindle head is adapted to be moved vertically along the ways 10 and 11 by a lead screw 16 rotatably supported in the machine in a suitable manner and having threaded engagement with a nut fixed in the spindle head. In addition to being rotatable in opopsite directions, the tool spindle 17 is movable in opposite directions longitudinally of its axis of rotation at different speeds to eilect both feed and rapid movements. The backrest block or outboard support G is movable simultaneously with the movement of the spindle head C by a vertical lead screw located within the backrest column D and connected to the drive for rotating the screw 16. The saddle E is movable longitudinally of the tool spindle along the ways 12 and the table F is movable transversely of the tool spindle along the ways 14- and 15 at different speeds by suitable mechanism.

The speed and direction of rotation of the spindle, etc., and the aforesaid movements of the various machine tool elements, such asthe feed and rapid movements of the spindle, head, saddle, table, etc., are performed by power and their operation may be controlled from any convenient place about the machine. The machine illustrated includes a reversible spindle drive electric motor arranged for ceiling mounting and enclosed within the guard 21 adjacent to the left-hand end of the machine, a reversible feed electric motor also located within the guard 21, and a reversible spindle rapid traverse electric motor mounted on the spindle head C. Other motors are employed but their location and operation are not necessary to an understanding of the present invention.

The spindle drive motor produces the spindle rotation and spindle feed movements. The feed motor produces the feed and rapid movements of the spindle head C, saddle E and table F. The spindle rapid traverse motor produces the rapid traverse movement of the spindle. The motors referred to are selectively connected to the various operating'mcchanisms through the medium of suitable speed change transmissions, clutches, etc., the controls for which are located on or adjacent to the base' A of the machine, spindle head C, and pendant control station H fixed to the lower end of a tubular rod connected to a universally movable arm 24 by a flexible cable 25.

After the desired spindle speeds and the desired feed rates have been selected by manual operation of the speed change transmissions the remaining operations of the machine are controlled from the electric control station H. The control station H includes a spindle rotation control or switch unit or assembly 169, a spindle jog and feed control or switch unit or assembly 170, a spindle rapid traverse control or switch unit or assembly 171, a spindle head feed and jog control or switch unit or assembly 172, a saddle feed and jog control or switch unit or assembly 173 and a table feed and jog control or switch unit or assembly 174L These units are adapted to control the movement of the spindle 17, the spindle head C, the saddle E, and the table F and are arranged so that the movement of an operative member to the right or left energizes the various power actuators for the machine tool elements so that the element controlled by the respective control unit or assembly moves or rotates in the direction in which the operating lever is moved. The control station H also includes a rapid traverse push button switch 175 which controls the rapid traverse movement of the spindle head, saddle, and table.

The control or switch assemblies-for controlling the movements of the various machine tool elements are constructed and arranged so as to permit simplification of the control wiring forthe machine and so as to present a compact control station. The control devices, with the exception of the rapid traverse-switch 175 which is a simple push button switch, are similar in construction and only the spindle rotation control or switch unit 169 is illustrated in the drawing and herein described in detail.

As illustrated, the switch unit 169 comprises a rotatable member'or rotor 176 having a shaft 177 supported for limited rotation in either direction from a normal or first position to control the operation or position of control instrumentalities in the form of electric switches or contacts mounted alongside the rotor 176. The shaft 177 extends forwardly through the wall 178 of the pendant control station H, the wall 178 supporting the switch unit 169 in the illustrated embodiment. The rotor is rotated either to the right or to the left from its normal position by a manually movable member or lever 179 supported in a diametrical slot 180 in the forwardly extending end of the shaft 177 of rotor 176. The lever 179 normally extends at a right angle to the rotor 176 and is pivoted about a pivot pin 181 which secures the lever 179 in i the slot 180.

Rotation of the rotor by swinging or pivoting the lever 179 about the axis of the rotor 176 controls the rotation of the tool spindle 17 by closing either the normally

open contacts

182, 183 or the normally open contacts 184, 185 mounted adjacent to but on opposite sides of the rotor 176. If the

contacts

182, 183 are closed by moving the lever 179 to the left, asthe control station H is viewed in FIG. 2, the tool spindle 17 will rotate to the left as the observer is facing the spindle. If the control lever 179 is moved to the right the contacts 184, 185 are closed, and the tool spindle will rotate to the right as viewed with the observer facing the tool-spindle.

The

contacts

182, 183 and 184, 185 are supported between spaced, parallel

vertical walls

186, 187 of insulating material constituting a part of the framework of the switch unit structure and extending substantially transversely to the rotor 176. The rotor 176 passes through central openings in the

walls

186, 187.

The fixed contact 182 is supported on the vertical leg of an L-shaped conductive member 190 which has one leg supported generally horizontally between shoulders 191 on the walls 186,187 near the upper edge thereof,

and the other leg extending downwardly therefrom. The

downwardly extending leg of the member is providedwith tabs 192 at its outer edges which are received in recesses in the

walls

186, 187. Electrical connections are made to the contact 188 by a connecting screw 194 which threads into the horizontal leg of the member 190.

The contact 183 is movably supported on the upper end of a generally vertical leaf spring 195 which urges the contact 183 away from contact 182 and is connected at its lower end to a conductive member 196 extending transversely between the lower portions of

walls

186, 187 and having tabs 197 at its outer ends which are received in recesses in the

walls

186, 187. The member 196'includes a conductive portion 198 extending outwardly of the member between the

walls

186, 187 and having a connecting follower surface 202 is just above the cam 201 when the lever 179 and the rotor 176 are in their normal position. The

contacts

182, 183 will then be open since the spring 195 normally urges the contact 183 away from the contact 182. When the lever 179 is swung to the left, the cam follower 202 rides up on the face of cam 201 closing the contacts. If the lever 179 is'swung to the right, the cam 201 is moved away from the cam follower surface 202 and, as a result, the contacts 182,183 remain in their normally open position.

The contacts 184, 185 are supported in a manner similar to the

contacts

182, 183 and a cam 203 on'the rotor 176 for controlling the position of the contacts 184, 185 is normally located just below the follower on the finger supporting the movable contact so that the cam follower surface for operating the contacts is engaged and the contacts moved to their closed position when the lever 179 is moved to the right from its normal position but remain in their normally open position when the lever 179 is moved to the left from its normal position.

It is often desirable to provide normally closed contacts which are opened when the

contacts

182, 183 are closed and contacts which are opened when the contacts 184, 185 are closed- In the switch illustrated, two pairs of normally closed contacts 188, 189 and 205,206 are located on opposite sides of the rotor 176 rearwardly of the normally

open contacts

182, 183 and 184, 185, the contacts 188, 189 being on the left side of the rotor when the viewer is facing lever 179. The construction and mounting of the

contacts

188, 189 and 205, 206 is. similar to that for the

contacts

182, 183 and 184, 185v and will not be described in detail. Suffice it to say that the rotor 176 is provided with

cams

207, 208 for controlling the position of the

contacts

188, 189 and 205, 206, respectively. As illustrated in FIG. 4, the cam 208 engages a cam follower surface 209- formed by a reverse bend in a spring finger 210 fixed at one end and having the movable contact 206 on the other end. When the lever 179 is in its normal position, the cam follower surface 209 engages the face of the cam 208 adjacent the upper. edge thereof and the contacts 205, 206are closed. If the lever 176 is moved to the left to close

contacts

182, 183 the cam follower 209 rides off the face ofthe cam 208 and the

contacts

205, 206 are opened. If however, the lever 179 ismoved to the right the face ofcam 208 remains in engagement with the cam follower surface 209 and the contacts do not open. It can now be seen that the

contacts

205, 206 will open when the

contacts

182, 183 are closed providing a means for opening an associated circuit when the spindle is rotated to the left. The

contacts

205, 206 may be connected into the motorplugging circuit for the spindle motor as described in the aforesaid patent or into any other circuit where it is desirable to open contacts when the spindle is rotated in a particular direction. The contacts 188, 189 are operated in a manner similar to the contacts 205, 286 and are opened when the contacts 184, 185 are closed. These contacts may be connected in any circuit such as the motor plugging circuit where it is desirable to open a circuit when the spindle is rotated to the right.

The rotor 176 and the lever 179 are yieldably urged to their normal position when moved therefrom by means best shown in FIG. 5 comprising a vertically supported compression spring 211 which is engaged at its upper end by one end of a lever 212 which is pivotally supported at its other end, the lever 212 supporting a cam follower wheel 213 intermediate its ends. The lever 212 is moved about'its pivot by a cam 214 keyed to the shaft 177 adjacent the insidesurface of Wall 178 and adapted to bear against the cam follower wheel 213 to move the lever 212 in a direction to compress spring 211whenever the rotor 176 and the lever 179 are moved from their normalposition. The cam 214 is provided with a notch 215 having sloping sides 215', 215" with which the wheel 213 remains in engagement when the rotor is moved.

I In the illustrated switch structure, the movement of the rotor from its normal position is limited by

stops

216, 217 mounted on the frame structure of the switch at a point above but adjacent to rearward end of the rotor 176. The rotor 176 carries a ring 218 with a radially projecting portion 219 which is located intermediate the

stops

216, 217 when the rotor is in its normal position and which engages the stop 216 to limit the rotative movement of the rotor in one direction and the stop 217 to limit the rotative movement of the rotor in the other direction. The sloping sides 215', 215 of notch 215 cause the force applied by the spring 211 to the cam 214 through the wheel 213 to urge the cam in a direction necessary to move the rotor back to its central or normal position'where no rotative force is applied to the cam by the spring whenever the rotor is moved therefrom Within the limits allowed by

stops

216, 217.

A face plate 228 is supported by the pendant control housing immediately in front of and parallel to the wall 178 of the housing through which the shaft 177 of rotor 176 extends. The face plate 228 is located outwardly ofthe rotor shaft 177 and is provided with an access opening 221 to permit the operator to move the lever 179. In order to provide a means for holding the lever 179 in a position to the right of or to the left of its normal position against the action of spring 211, the face plate 220 is provided with an ear 222 which extends downwardly from the upper side of the access opening 221 at a point immediately above the lever 179 when it is in its normal position. When the lever 179 is moved to either side of its normal position to cause the rotation of the spindle, the lever will move out from under the ear 222 and may be pivoted about the pivot pin 181 outwardly of the face plate so that it engages the side of the ear and is prevented from returning to its normal position. When the lever 179 is latched the spindle will continue rotating until the lever is released and returned by the spring 211 to its normal or central position. The lever for the spindle head feed and jog switch assembly 172 is shown,

for purposes of illustration, in the latched position in FIG. 2. The sides of the ear may be sloped to aid in the latching operation, as illustrated in FIG. 2. The

control switch or unit described enables momentary movement or continuous movement of the spindle in either direction to be accomplished by the movement of a single lever, namely, lever 179 and the lever position will indicate direction of movement of the machine tool element permitting elimination of directional lights.

To provide a switch which is extremely flexible and which is capable of being easily assembled and disassembled, the switch frame may be divided transversely into sections, as illustrated in FIG. 3, and assembled by a plurality of bolts 227 which are parallel to the rotor verse walls of the switch are each part of separate sec- 7

tions

228, 229 and 230 which include shoulders 231 extending outwardly from the transverse walls to properly space the walls of the switch.

The housing for pendant control station H is preferably L-shaped, as illustrated in FIG. 2, to provide narrow housing portions 233 for enclosing the various switches, thus providing side surfaces 234 which may be used by the operator as gripping surfaces for his fingers when moving the switch lever with his thumb to provide additional leverage and also prevent the control station H from swinging. Since the length of the control station will normally make it difficult to grip either the top or bottom of the housing for the control station when moving the switch lever for the spindle head feed and jog switch assembly 172, the housing is provided with

bosses

235, 236 immediately above and below the access opening for the actuating lever of the switch assembly. When moving the actuating lever, the operator may utilize these bosses to provide additional leverage. If desired, similar bosses can be provided for the other switches.

The switch units for controlling the feed and jog movements of the spindle 17, spindle head C, saddle E and table F, as previously stated, are similar in construction to the construction of the spindle rotation switch unit 169 described and are, therefore, not described in detail. The switch assembly 171, however, for controlling the rapid traverse of the spindle 17 has no means for locking its control lever in either its left or right position and must be held by the operator to rapid traverse continuously.

While it has been stated that the switch assemblies are the same in construction it will be understood that the number and type of contacts used with any particular switch unit may vary depending upon the number of electrical operations to be performed by the movement of the switch lever. The switches will, however, generally have the normally open contacts which are closed when the rotor is moved in one direction but remain open when moved in another direction as described in

connection'with contacts

182, 183 and 184, 185 of switch 169. It will also be well understood by those skilled in the art that while the illustrated embodiment utilizes the closing of normally open contacts to complete the electrical circuits for moving the various elements and members of the machine it is possible to control these movements by the opening of normally closed contacts which are constructed, arranged, and operated in accordance with the present invention. Alternatively the cams 201, 288 or equivalent parts can be used to actuate fluid pressure valves controlling fluid pressure actuated motors instead of electric motors from one position to which they are biased, such as a closed position, to a second position, such as an open position.

In operating the machine the spindle 17 is first caused to rotate either to the right or to the left, the viewer facing the projecting end of the spindle, by moving the control lever of switch unit 169 to the left or to the right. If the control lever is moved to the left,

contacts

182, 183 are closed which completes a circuit connecting the spindle drive motor to a power supply in such a manner that the drive motor rotates in the direction necessary to cause the spindle 17 to rotate to the left. Rotation of the spindle continues so long as the lever is maintained in the left position either manually or by being latched therein. If it is desired to rotate the spindle 17 to the right, the switch lever 179 of switch unit 169 is moved to the right which closes normally open contacts 184, 185 and completes a circuit connecting the spindle drive motor to the power supply such that the drive motor rotates in the direction necessary to rotate the spindle to the right. The rotation of the spindle 17 to the right continues until the lever 179 is released or unlatched and allowed to return to its central position.

'27 To feedthe spindle 17 to the-right, the spindle feed switch 170- is moved toward the right. will be fed to theright-as long as the switch lever is manually heldorislatched in its right position. If it is desired to feed the spindle 17 to the left, the spindle feed.

switch 170is moved to the left. The'spindle 17 will be fed-to the left'aslongasthe lever for the switch is held manually or by latching on itsleft position to prevent its return to its central position.

The spindle 17 may be rapid traversed by movement of the lever of spindle rapid traverse switch 171 provided the spindle jogand feed switch is in a feed position. The spindle 17 will be traversed as long as the switch lever is held in a right'or left position.

The feed and jog movements of the spindle head C, table F, and the saddle E are caused by energizing the feed motor to rotate in the direction necessary to move the particular element in the desired direction and to shift a clutch for connecting the particular element to the motor. The saddle E may be moved to the right by moving the lever of saddle jog and feed switch 173 to the right to connect the feed motor to the power supply sothat it rotates in the necessary direction to move the saddle to the right. If the saddle E is to be moved to the left, the switch lever of switch 173 is moved to the left; The. saddle is moved continuously as long as the lever for the switch is manually held or latched-in one of its rotated positions.

The electrical circuit for controlling the movement of the table F is similar to that for controlling the movement of the saddle E and-the table F maybe movedback, i.e. towards the rear of the machine by moving the lever of the tablefeed and jog control switch 174 toward the right as it is viewed in FIG. 2, which is toward the back of the machine. Moving the lever of table feed control switch in a forward direction, i.e. to the left when facing the lever, closes reverse circuits for the-feed motor. The

movement of the table F continues as long as the lever of switch 174 is; held or latched in one of its rotated positions.

The spindle head C may be moved in a downward direction by movingthe lever of control switch 172 to the right. To move the spindle head C up, the lever of the spindle head switch 172 is moved toward the left. The movement of the spindle head continues in the selected direction as long as the lever of switch 172is manually held or latched in either its right or left position.

The spindle head'C, table F or saddle E may be rapid traversed'by depressing push button switch 175.

From theforegoing it will be apparent that the objects of the invention heretofore enumerated and others have been accomplished and that I'have provided a novel and improved manual control for one or a plurality of power actuated members intended to be operated under the directvisual control of the operator and a small compact control. station, having a plurality of manually operable controls for executing a. plurality of movements of a particular member, such as, jog and feed movements of machine tool elements without the necessity of the operator removing his hand from one control member to another, thereby reducing thepossibility of inadvertent operation of a member and damage to either the apparatus or the work.

While'the,preferred embodimentvof the invention has been described with considerable detail, the invention-is not limited to the particular construction shown and it is my-intention to cover hereby all adaptations, modifications and uses thereof which come within the practice of those skilled in the art to which the invention relates and the scope of the appended claims.

Having thus described the invention, I claim:

1. In. an electric switch device especially applicable for controlling the operation of a member movable by power under the visual supervision of an operator, a

The spindle 17 manually movable member, means supporting said manually movable member for movement ina plane between a first inoperative and a second'operative position, means yieldably biasing said manually movable member to said first position, means supporting said manually movable,

member for oscillatory movement about an axis parallel with said plane, and means selectively engageable by;

said manually movable member when in said second position whereby said manually movable member may be selectively latched in said second position upon manual oscillation thereof about said axis. I

2. In an electric switch device especially applicable for controlling the operation of a member movable by power under the visual supervision of; an operator, a:

manually movable member, means supporting said man-- ually movable member for movement in a plane between first and second positions, means yieldably urging said? manually movable member to said first position,- electrical contacts, means operatively connecting said manually movable member and said contacts whereby said contacts are in one position when said manually movable member is in said first position and in another poistion when said manually movable member is in said second position, means supporting said manually movable member for oscillatory movement about an axis parallel with said plane, and means selectively engageable by said manually movable member when in said second position whereby said manually movable member may be selectively latched in said second position upon manual oscillation thereof first position, cooperating electrical contacts operatively.

connected to said manually movable member and positioned to prevent operation of said member when said manually movable member is in said first position and positioned to cause operation of said member when said manually movable member is in said second position,

means supporting said manually movable member foroscillatory movement about an axis parallel with said plane, and means selectively-engageable by said manually movable member wherein said second position whereby said manually movable member may be selectively latched in said second position upon manual oscillation thereof about said axis.

4. In an electric switch device espeically applicable for controlling the operation of a member movable by power in two directions under the visual supervision of an operator, a manually movable member, means supporting said manually movable member for movement in a plane between a first inoperative andtwo operative positions, said first inoperative position being intermediate said two operative positions, means yieldably urging said manually movable member to. said first inoperative posi: tion, electrical contact means operatively connected to said manually movable member and in position to prevent operation of said member when said manually movable member is in said first inoperative position and in position to cause operation of said member in opposite direction when said manually movable member is insaid operative position, means supporting saidmanually movable member for oscillatory movement about an axis parallel with said plane, and meansselectively engageable by said manually movable member when in said operative positions whereby said manually movable member may be selectively latched in said operative positions upon manual oscillation thereof about'said axis.

5. In an electric switch device a pair of co-operating contacts, a lever supported for movement within a plane from a normal position for operating said, contacts, means operatively connecting said lever and said contacts to actuate the latter on movement of said lever from said position, means biasing said lever toward said normal position when moved therefrom, means supporting said lever for pivotal movement in a plane transverse to the first mentioned plane, and latching means selectively engagea'ole by said lever when pivotally moved in'the last recited plane for selectively andreleasably securing said lever in a position to one side of said normal position.

References Cited in the file of this patent UNITED STATES PATENTS Curtain Dec. 22, 1959

Claims

1. IN AN ELECTRIC SWITCH DEVICE ESPECIALLY APPLICABLE FOR CONTROLLING THE OPERATION OF A MEMBER MOVABLE BY POWER UNDER THE VISUAL SUPERVISION OF AN OPERATOR, A MANUALLY MOVABLE MEMBER, MEANS SUPPORTING SAID MANUALLY MOVABLE MEMBER FOR MOVEMENT IN A PLANE BETWEEN A FIRST INOPERATIVE AND A SECOND OPERATIVE POSITION, MEANS YIELDABLY BIASING SAID MANUALLY MOVABLE MEMBER TO SAID FIRST POSITION, MEANS SUPPORTING SAID MANUALLY MOVABLE MEMBER FOR OSCILLATORY MOVEMENT ABOUT AN AXIS PARALLEL WITH SAID PLANE, AND MEANS SELECTIVELY ENGAGEABLE BY SAID MANUALLY MOVABLE MEMBER WHEN IN SAID SECOND POSITION WHEREBY SAID MANUALLY MOVABLE MEMBER MAY BE SELECTIVELY LATCHED IN SAID SECOND POSITION UPON MANUAL OSCILLATION THEREOF ABOUT SAID AXIS.