US2012493A

US2012493A - Automatic trip mechanism

Info

Publication number: US2012493A
Application number: US340119A
Authority: US
Inventors: John S Barnes
Original assignee: WF and John Barnes Co
Current assignee: WF and John Barnes Co
Priority date: 1929-02-15
Filing date: 1929-02-15
Publication date: 1935-08-27
Anticipated expiration: 1952-08-27

Description

J. S. BARNES AU'IOMATIQ TRIP MECHANI SM Aug. 27, 1935.

2 Sheets-Sheet 1 Filed Feb. 15, 1929 Aug. 27, 135, J. 5. BARNES AUTOMATIC TRIP MECHANISM Filed Feb. 15, 1929 2 Sheets-Sheet 2 Patented Aug. 27, 1935 PATENT OFFICE AUTOMATIC TRIP MECHANISM 'John S. Barnes, Rockford, Ill., assignor to W. F.

and John Barnes Company, Rockford, Ill., a

corporation of Illinois Application February 15, 1929, Serial No. 340,119

17 Claims.

This invention relates to an automatic trip mechanism for hydraulically operated machine tools adapted for universal application and permitting of the fully automatic or semi-automatic control of the operation of the machines.

- tuateld plunger for moving the same in'theother The principal object is to provide a trip mechanism of an extremely simple and serviceable form which, depending, of course, on the type of valve and pump provided in connection there'- with, is adaptable to any kind of cycle from the simple form consisting of rapid traverse, feed and rapid returnto the more complicated cycles involving either rapid traverse, feed, reverse feed and rapid return, or even such a cycle as rapid traverse, feed, rapid traverse and feed again one or more times, and finally rapid return. The trip mechanism is, therefore, suitable for use with practically any kind of machine tool having a reciprocating carriage and is suitable to practically any kind of operation, whether it be drilling, boring, reaming, tapping, milling, grinding, or what not.

()ne feature of the trip mechanism of my invention consists in the use of aspring-actuated plunger which is normally urged in one direction and has connection through suitable linkage with the valve stem so as to tend to move the same correspondingly in one direction toward rapid return position. This plunger has a hand lever connected therewith permitting the movement thereof against the action of its spring to rapid traverse position at the beginning of a cycle, and there is provided in connection with the plunger a latch, spring-pressed toward engagement with notches provided in spaced relation on the plunger, said latch being arranged to hold the plunger in rapid traverse position by engagement in the notch provided for that purpose, and being arranged to be tripped automatically by dogs in the operation of the carriage to release the plunger for movement to one or more other positions, depending on the nature of the cycle, until finally the plunger is released and allowed to move to rapid return position. A special advantage of this form of trip mechanism lies in the fact that it permits of automatic resetting of the plunger, involving, of course, a reloading of its actuating spring; this is accomplished by providing one dogactuated plunger for releasing the latch, whereby movement of the spring-actuated plunger in one direction is brought about, and another dogactuated plunger connected with the spring-acdirection against the action of its spring. This permits alternating between feed and rapid traverse by simply resetting the spring-actuated plunger, thus making the trip mechanism suitable for use wherever intermittent feeds are required, as for example in a machine for boring crank shaft hearings, in which case a great saving in time is derived by traversing the tool from one bearing to the next and feeding only during the boring operation in the bearing.

Another feature of this trip mechanism consists in the provision of a hand lever in connecm tion with the latch, permitting manual release of the spring-actuated plunger at any point in the cycle for movement back to rapid return position so as to bring about the return of the carriageto the starting position. This hand lever is therefore in the nature of a safety. By manipulation of both hand levers at the same time, the latch being released by the lever in one hand and the spring-actuated plunger being manipulated by the lever in the other hand, it is also possible to reset the valve by hand as desired, as for example, in making a new set-up on the machine.

The invention is illustrated in the accompanying drawings, wherein- Figure 1 is a side view of one end of a horizon- 2 ta1 drilling or boring machine equipped with my improved automatic trip mechanism;

Fig. 2 is a section through the casing showing the parts of the trip mechanism therein in elevation;

Fig. 3 is a transverse section on the line 3-3 of Fig. 2;

Fig. 4 is a perspective view of a few of the parts of said mechanism shown in disassembled spaced relation so as better to indicate the form thereof 35 and how the same are arranged to cooperate with one another, and

Figs. 5 and 6 are fragmentary sectional details of modifications of the form of spring-actuated plunger shown in Fig, 2 required in trip mecha- 4 nisms designed for different cycles.

The same or similar reference numerals are applied to corresponding parts throughout the views.

The present trip mechanism is one designed for use with Oilgear units for machine tools where a valve, such as that shown at I, having the stem or control member H thereof shiftable endwise to different positions, is arranged to control the operation of a pump 10 to vary the pumps delivery and accordingly change the speed and direction of travel of a slidable head or carriage l2 on its ways I 3 on the bed H. The pump has connection with the opposite ends of a hydraulic cylinder for the delivery of fluid 1 theretoon either side of the ram. There is indicated in dotted lines in Fig. 1 a stationary cylinder and a movable ram, but, of course, the relationship might be reversed if desired, and the ram made stationary and the cylinder movable. The pump may be of the type disclosed in Ferris Patents 1,753,562 and 1,854,127. In the present disclosure nothing is illustrated beyond the valve which or vitrols the delivery of the pump, and the pipes 1e "ling from the opposite ends of the cylinder if connection with the pump. It happens that the particular valve illustrated is one suitable for the simplest form of cycle, namely, rapid traverse, feed, and rapid return. This form of cycle is suitable for a great variety of operations but, of course, the invention is not limited thereto, but, as a matter of fact, is adaptable to use where any kind of variation of this cycle is required, as will presently appear. The trip mechanism of my invention is designated generally by the reference numeral I5 in Fig. 1, shown mounted on the side of the bed M in the path of travel of dogs Iii-l9, adjustably mounted in the T-

slots

20 and 2| provided on the side of the carriage l2, and it will presently appear how there is a rapid traverse of the carriage until the dog It trips the mechanism l5 into feed, and how the carriage feeds until the dog I! resets the trip mechanism for the carriage to resume rapid traverse until the dog I8 trips the mechanism again for the carriage to resume the feed, the feed continuing until the dog l9 trips the mechanism and throws the carriage 12 into rapid reverse. In other words, the trip mechanism is one designed to be reset so that any number of alternations between feed and rapid traverse can be accomplished, such intermittent feed operation being desired, for example, where the carriage l2 has a boring bar driven by the spindle 22 and it is desired to traverse upon the completion of the boring operation in one bearing after another in a crank case. The machine illustrated is a doubleend machine having two carriages l2 at opposite ends of the bed It arranged to approach the work from opposite ends thereof and to operate in unison. No limitation is, however, to be regarded as imposed upon the application of my invention, by reason of reference to this particular machine or to the particular boring operation mentioned.

The trip mechanism I5 comprises a hollow casing 23 arranged to be bolted, as shown at 29, to the side of the bed I 4. An elongated bearing 25 is suitably cast integral with the casing and provides a mounting for a bolt 26. The bolt 26 provides support for a belT-crank lever 21 and a hand lever 28, both inside the casing 23, and still another hand lever 29 outside the casing. The hand lever 28 is independent of the other two levers, but the

levers

21 and 29 are keyed together by a washer 30 which has lugs 3| on opposite faces thereof arranged to engage in

slots

32 and 33 provided in the hubs of the

levers

21 and 29 respectively. A nut 34 threading on the outer end of the bolt 26 keeps the levers in the assembled relationship shown. The hand lever 28 projects through a slot 35 in the end wall of the casing 23 and has a hand grip on the outer end thereof. The hand lever 29 similarly has a hand grip on the upper end thereof. Now, the bellcrank lever 21 has the outer end of the one arm thereof pivotally connected by means of a pin with a plunger 31, and the hand lever 28 has the inner end thereof similarly connected with a plunger 38. the two plungers being slidable in bores 39 provided therefor in the wall of the casing, and both having the upper ends thereof beveled off, as shown, for cooperation with the rounded faces of the dogs IS-IS. The

plungers

31 and 38 will be referred to as dog-actuated plungers. The other arm of the bell-crank lever 21 is pivotally connected by means of a pin with the inner end of a plunger 49 slidable in a horizontal bore 4| provided in a boss formed on the bottom wall of the casing. The outer part of the plunger 40 is of reduced diameter, as shown at 42, and projects through a tube 43 mounted on the casing and through a hole in a cap 46 threaded on the outer end of the tube. A coiled compression spring 95, fitting about the reduced part 92 of the plunger and bearing at one end against the cap 46 and at the other end on the annular shoulder 46 on the plunger, tends normally to move the plunger to the left and accordingly raise the dog-actuated plunger 3'1. The plunger 90, by reason of its spring 65, will be known as the spring-actuated plunger. One side of the spring-actuated plunger 40 is milled off to a certain profile, as shown at M, to provide notches a, b, c, and d, for reception of a latch 98 in different positions of the plunger. The latch 48 is pivotally connected with the hand lever 28, as shown at 49, and is arranged to be raised by said lever against the action of a coiled compression spring 50 which serves normally to urge the latch 48 toward the plunger 40 for engagement in whichever notch comes into position beneath the same. The lower end of the latch 98 is beveled oil, as shown at 5|, and the corresponding sides of the notches a, b, and e are likewise beveled So that the plunger 90 can be moved forcibly to the right, the latch 48 being arranged simply to ride out of one notch into the next in such movement of the plunger, but movement of the plunger to the left is permitted only upon release of the latch 68, either by manipulation of the lever 28 by hand or by tripping of the dogactuated plunger 38. Before proceeding to a. description of the operation of the mechanism, attention is called to Fig. 1, showing how the hand lever 29 is connected with the valve stem II by means of a bell-crank arm 52 on the lever 29 connected through a link 53 with levers 59 and 55 on the shaft 56, the lever .55 having a link 5? connecting the same with the valve stem H. Different linkages are provided in different machines eonnecting the hand lever 29 with the valve stem H, depending on the position of the valve with relation to the trip mechanism.

In describing the operation, let us assume that the spring-actuated plunger 90 is in neutral position with the latch 48 engaged in notch c, to which position the plunger was moved at the end of the previous cycle by the engagement of a set screw 58 with a pad portion 59 provided on the hand lever 29 as the carriage l2 arrived at the end of its rapid return movement. The operator, to start the carriage moving to the right, takes hold of the hand lever 29 and throws it to the left so as to move the spring-actuated plunger 66 to the right against the action of the spring 45 until the latch 88 drops into notch a for rapid traverse of the carriage. The valve stem I I is accordingly shifted to the left as will be evident upon study of Fig. l. The carriage continues on the rapid traverse until the dog is, which is in the same plane with the dogs i8 and I9, comes into engagement with the dog-actuated plunger 38 and raises the latch 98 against the action of its spring 59 just enough for the end of the latch to clear the right side of the notch a so that the plunger 40 is released and moved under the action of its spring 45 to the left a distance corresponding to the distance between the notches a and b, the plunger 40 being stopped by the engagement of the end of the latch with the right side of the notch b. This movement of the plunger 40 necessarily means a corresponding movement of the bellcrank lever 21 and hand lever 29, and the valve stem ii is accordingly shifted to the right from rapid traverse to feed position. There is also a slight elevation of the dog-actuated plunger 31 as a result of this change of the position of the spring-actuated plunger 40. The carriage proceeds on the feed movement until the dog H, which is in the plane of the plunger 31, engages the latter and depresses the same back to its former elevation which is enough to move the spring-actuated plunger 40 to the right against the action of its spring 45 back to its first position, namely, wherein the latch 48 drops into notch a. This'phase of the operation is referred to as automatic resetting of the plunger M, or valve stem H, as the case may be. The valve stem i i is accordingly shifted to the left back to rapid traverse position, and the carriage i2 is accelerated in its travel up to the position where the next feed is to commence. That position is determined by the dog it which comes into engagement with the plunger 38 to lift the latch 48 the same as before to release the plunger Qt for movement under the action of its spring just enough to shift the latch from notch a to notch 19. Thus, the carriage is thrown back into feed. The carriage continues on the feed movement until the dog i9 comes into engagement with the plunger 38 and depresses the same enough to raise the latch it clear of the right side of the notch b whereupon the plunger i is thrown to the left under the action of the spring t5 past the neutral position, defined by the notch c, to the rapid return position in which the latch t8 engages the right side of the notch 11. The valve stem ii is accordingly shifted to the extreme right, and the hand lever 29 is also thrown to the right, as should be evident from a study of Fig. 1. The carriage l 2 is, therefore, caused to start on its return movement to the left, and it is arranged at the end of its moveemnt to have the set screw 58 come into engagement with the pad portion 59 on the hand lever 29 and move the latter to the left until the plunger ill is shifted to the right enough for the latch 8 to drop into notch c, whereupon the carriage comes to a standstill, inasmuch as this position of the plunger 40 corresponds to the neutral position of the valve stem 11 l It will, therefore, be seen that the mechanism, once the same has been set manually at the beginning of the cycle, is arranged to be tripped automatically in the movement of the carriage to throw the carriage from traverse into feed and back again into tra erse and again into feed and'finally rapid return, the mechanism being designed in such a way that resetting thereof automatically is rendered possible and any number of alternations between feed and rapid traverse can be provided for. If, for any reason, the operator should want to return the carriage to its starting position at any point in the cycle he could do so by simply taking hold of the hand lever 28 and raising the same so as to release the plunger 40 for movement under the action of its spring to rapid return position. The hand lever 28 is, therefore, in the nature of a safety. The provision of the lever 28 also makes it possible for the operator to reset the trip mechanism and correspondingly reset the valve by hand at any point in the cycle, by grasping the lever 29, say with the left hand, and the lever 28 with the right hand and manipulating the plunger 40 by means of the lever 29 while the latch 48 is held raised by means of the lever 28. There is frequently occasion for this in making a new set-up on the machine.

In Figs. 5 and 6, I have shown modified forms of the spring-actuated plunger 40 adapted for trip mechanisms used in connection with valves of a different form from that above described. The plunger 40 in Fig. 5 is one having a set of notches designed for use with a valve arranged to be shifted in either direction from a neutral position for traverse and feed in either direction. The notch 0' corresponds to the notch c in Fig. 2, the plunger 40 and the valve stem associated therewith being in neutral position when the latch 48 is engaged in this notch. The notch 1' corresponds to the notch a of Fig. 2, being that for rapid traverse, and notch b' corresponds tonotch b of Fig. 2, the same being for feed. Notch 0 corresponds to notch 12 of Fig. 2, the same being for rapid return, but the'notch d is one between the neutral notch c and rapid return notch e, and when the latch 58 drops into this notch, the valve stem is in reverse feed position. In the operation of a mechanism using this form of plunger and having the proper valve to go with it, the plunger 40 at the beginning of the cycle is shifted to the extreme right so that latch d8 drops into notch a for rapid traverse. At the end of the rapid traverse a dog, corresponding to the dog IE of Fig. 1, trips the mechanism to allow the plunger ill to move to the left so that latch 68 can drop into notch b for feed movement of the carriage. At the end of the feed movement a dog, corresponding to the dog 99, trips the mechanism and the plunger 40 is thrown to the left until the end of the latch d8 stops it by engagement with the right side of notch d, in which position of the plunger the valve stem is in reverse feed position. The carriage at the end of the reverse feed has still another dog arranged to trip the mechanism to allow the plunger 4!] to be thrown to the left until latch 38 stops it by engagement with the right side of notch e, in which position the valve stem associated with the plunger is in rapid return position. The carriage continues on the rapid return in the same way as above described, untilthe set screw 58 moves the hand lever 29 back to the neutral position in which the latch 48 drops into notch c. The plunger 40 of Fig. 6 is one designed for use with a valve the plunger of which is arranged to be shifted from neutral to rapid traverse, and from there to first feed and second feed and finally rapid return, and thereafter back to neutral. This plunger has notches a"--e. The notch 11" corresponds to the notches c of Fig. 2 and c of Fig. 5, the same being that for neutral. The notch a" is that for rapid traverse, the notch b" for first feed, the notch c" for second feed, and the notch e for rapid return. It is not believed necessary to go through a lengthy discussion of the way in which this plunger will be operated; that should be clear from a study of the operation of the plungers 40 of Figs. 2 and 5 discussed above.

It is believed the foregoing description conveys a clear understanding of my invention and also clearly demonstrates the universaladaptability thereof to practically any kind of, machine tool for the performance of an almost infinite variety of machine operations.

I claim:

1. In a mechanism of the character described, the combination with a single control member arranged to be shifted in either direction to control the speed and direction of travel of the carriage of a machine tool in rapid traverse and feed movements, of a control casing, a manually operable control lever provided in connection with said casing, a plunger mounted in said casing and projecting therefrom, connections between the plunger and lever and also with the control member whereby movement of the control lever communicates movement to the control member and shifts'the plunger to a predetermined position, a plurality of dogs for successively operating said plunger in the movement of the carriage after the manual operation of said lever whereby to shift the control member successively in a predetermined manner for forward movements, means for shifting said plunger at the end of the forward movement past neutral position to reverse position, to cause return movement of the carriage and means outside the casing arranged in the movement of the carriage at the end of the cycle to come into engagement with and move the control lever back to neutral position and correspondingly shift the control member back to neutral position.

2. In a trip mechanism for a hydraulic control system adapted for use in connection with a reciprocable machine tool part, the combination with a control member arranged to be shifted, of a spring-actuated plunger having connection with said control member whereby to be shifted with it or shift the same under spring action, a manually operable member having connection with the control member and plunger arranged at the beginning of a cycle to shift the control member and at the same time move the plunger toa predetermined position, a latch arranged releasably to hold the plunger in set position, a plurality of dogs movable with the machine to-ol part, means arranged to be automatically operated by said dogs in the movement of the machine tool part at different points in the cycle to trip the latch and allow the plunger to move to bring about a corresponding movement of the control member, another means manually operable at any point in the cycle arranged to trip said latch so as to allow said plunger to move, and means arranged to be operated in the movement of the part at the end of the cycle to move the control member back to neutral position against the action of the spring-actuated plunger.

3. In a trip mechanism for a hydraulic control system adapted for use in connection with a reciprocable machine tool part, the combination with a control member arranged to be shifted, of a spring-actuated plunger having connection with said control member whereby to be shifted with it or shift the same under spring action, a manually operable member having connection with the control member and plunger arranged at the beginning of a cycle to shift the control member and at the same time move the plunger to a predetermined position, a latch arranged releasably to hold the plunger in set position, a plurality of dogs-movable with the machine tool part, means arranged to be automatically operated by said dogs in the movement of the machine tool part at different points in the cycle to trip the latch and allow the plunger to move to bring about a corresponding movement of the control member, and means arranged to be operated in the movement of the part at the end of the cycle to move the control member back to neutral position against the action of the spring-actuated plunger, said last mentioned means comprising a part arranged at the end of the cycle to come into direct engagement with the manually operable member to move the same back to neutral position and correspondingly shift the control member back to neutral position.

4. In a trip mechanism of the character described, adapted for use with a reciprocable machine tool part, the combination with a valve member arranged to be shifted to different positions, of a spring-actuated plunger arranged to be shifted with the valve member or to shift the latter under spring action, a manually operable member having connection with the valve member and plunger arranged at the beginning of a cycle to shift the valve member from neutral position and at the same time shift the plunger to a certain position, a latch for releasably holding the spring-actuated plunger in set position, and a pair of dog-actuated plungers, the one dogactuated plunger being associated with said valve member and the other dog-actuated plunger being associated with the latch, the first mentioned dog-actuated plunger being arranged to be automatically operated in the forward movement of the part to shift the valve member a predetermined amount for a speed change and the last mentioned dog-actuated plunger being arranged at the end of the forward movement to be automatically operated to trip the latch member whereby to move the valve under spring action of the first plunger past neutral to reverse position, and a manually operable means in connection with the first dog-actuated plunger arranged for operation at anypoint in a cycle to trip the latch and release the spring-actuated plunger.

5. In a trip mechanism of the character described, adapted for use with a reciprocable machine tool part, the combination with a valve member arranged to be shifted to different positions, of a spring-actuated plunger arranged to be shifted with the valve membe or to shift the latter under spring action, a ma ually operable member having connection with the valve member and plunger arranged at the beginning of a cycle to shift the valve member from neutral position and at. the same time shift the plunger to a certain position, a latch for releasably holding the spring-actuated plunger in set position, and a pair of dog-actuated plungers, the one dog-actuated plunger being associated with said valve member and the other dog-actuated plungposition, the first mentioned dog-actuated plunger having a lever providing a connection between it and the latch, said lever having an extension arranged to be operated manually to trip the latch and release the spring-actuated plunger.

6. In a trip mechanism of the character described, adapted for use with a reciprocable machine tool part, the combination with a valve member arranged to be shifted to different positions, of a spring-actuated plunger arranged to be shifted with the valve member or to shift the latter under spring action, a manually operable member having connection with the valve member and plunger arranged at the beginning of a cycle to shift the valve member from neutral position and at the same time shift the plunger to a certain position, a latch for releasably holding the spring-actuated plunger in set position, and a pair of dog-actuated plungers, the one dog-actuated plunger being associated with said valve member and the other dog-actuated plunger being associated with the latch, the first mentioned dog-actuated plunger being arranged to be automatically operated in the forward movement of the part to shift the valve member a predetermined amount for a speed change and the last mentioned dog-actuated plunger being arranged at the endof the forward movement to be automatically operated to trip the latch member whereby to move the valve under spring action of the first plunger past neutral to reverse position, the two dog-actuated plungers being mounted alongside one another for movement vertically, and being arranged to be depressed by dogs, a lever pivotally mounted intermediate its ends having connection with the first mentioned dogactuated plunger at one end, and connection with the latch at the other end whereby to move the latch out of locking position when said plunger is actuated by a dog, the spring-actuated plunger in the movement of said latch being arranged to move in a certain direction under spring action, and a pivotally mounted bell-- crank lever having the one arm thereof connected with the other dog-actuated plunger, and the other arm thereof connected with the spring actuated plunger, said bell-crank lever being arranged upon dog actuation of said plunger to move the spring-actuated plunger in the opposite direction against the spring action.

7 In a trip mechanism adapted for use in connection with a reciprocable machine tool carriage, the combination with a control member arranged to be shifted to positions in either direction-from a neutral position, of a manually operable member having connection with said control r member for shifting the same from neutral position in one direction, as for example to produce movement of the machine tool carriage in a certain direction from a starting position, spring means arranged in the shifting of the control member by the manually operable member to be placed under tension, a catch therefor to hold the same under tension, a plurality of dogs mova new position, as for example, to bring about return movement of the machine tool carriage,

and means arranged for engagement directly with the manually operable member in the movement of the carriage at the end of the cycle to move the same back to neutral position and correspondingly shift the control member back to neutral position against the action of said spring means.

8. The combination with a base, a carriage reciprocable thereon, and a valve controlling the fluid delivery irom a pump for hydraulically operating the carriage, of a control casing mounted on the-base, a hand lever mounted directly on the outside of the control casing and having a mechanical operating connection with the valve, said hand lever being manually operable for manual operation of the valve, a control member.

rangedt-o operate said member in the movement of the carriage in one direction, and means arranged in the movement of the carriage in the other direction to engage the hand lever itself to move the same and operate the valve.

9. In a control unit of the character described, the combination with a reciprocable machine tool carriage having dogs thereon, of a stationary casing, a pair of plungers mounted for reciprocation in and extending from said casing for depression by the dogs and disposed substan-- tially parallel with one another, a support in said casing, a bell crank lever pivotally mounted on the support, a control-member shiftable by movement of said bell crank lever, said bell crank lever being pivotally connected by one arm with the one plunger, a third plunger mounted for reciprocation in the control casing and pivotally connected to the other arm of the bell crank lever, spring means normally urging said plunger to move in one direction, a latch for locking the third plunger, a lever pivotally mounted on said support having pivotal connection with the other of the two first mentioned plungers and arranged when operated thereby to release the latch, said support extending through thewallof said casin a second bell crank lever mounted on said support outside the casing, and means providing an operating connection between the two bell crank levers whereby they are caused to turn together, the one arm of the second bell crank lever being arranged to be manually operated, and the other arm thereof being adapted for connection with the control member to be actuated thereby.

10. In a control unit of the character described, the combination with a reciprocable machine tool carriage having dogs thereon, of a stationary casing, a pair of plungers mounted for reciprocation in and extending from said casing forelepression by the dogs anddisposed substantially parallel with one another, a support in said casing, a bell crank lever pivotally mounted on the support, a controlmember shiftable by movement of sail bell crank lever, said bell crank lever being pivotally connected by one arm with the one plunger, a third plunger mounted for reciprocation in the control casing and pivotally connected to the, otherarm of the bell crank lever, spring means normally urging said plunger to move in one direction, a latch for locking the third plunger, a lever pivotally mounted on said support having pivotal connection with the other of the two first mentioned plungers and arranged when operated thereby' to release the latch, the last mentionedlever having a free end extending through an opening provided in a wall of the casing to permit manual operation thereof from outside the casing independently of the operation of said lever by its plunger, and a second bell crank lever turning with the first bell crank lever and having one arm thereof arranged for manual operation, and the other arm thereof arranged for connection with the control member to be actuated.

11. In a trip mechanism of the character described adapted for use in connection with a reciprocable machine tool part, the combination with a valve member arranged to be shifted to difierent positions, of a spring-actuated plunger arranged to be shifted with the valve member or to shift the latter under spring action, a manually operable member having connection with the valve member and plunger arranged at the beginning of a cycle to shift the valve membar from neutral position and at the same time shift the plunger to a certain position, a latch for releasably holding the spring-actuated plunger in set position, a pair of dog-actuated plungers mounted alongside one another and arranged to be depressed by dogs on the reciprocable machine tool part, a lever pivotally mounted intermediate its ends having connection with one of said plungers at one end and with the latch at the other end to release the latch when said plunger is actuated, the spring-actuated plunger upon release of the latch being arranged to move in a certain direction under spring action, said lever having an extension manually operable to permit release of the latch at will, and a pivotally mounted bell-crank lever having the one arm thereof connected with the other dog-actuated plunger and the other arm thereof connected with the spring-actuated plunger, said bell-crank lever being arranged upon dog actuation of the plunger to move the spring-actuated plunger in the opposite direction against the spring action.

12. In a trip mechanism of the character described adapted for use in connection with a reciprocable machine tool part, the combination with a valve member arranged to be shifted to different positions, of a spring-actuated plunger arranged to be shifted with the valve member or to shift the latter under spring action, a latch for releasably locking the spring-actuated plunger against movement in one direction, a pair of dog-actuated plungers mounted alongside one another and arranged to be depressed by dogs on the reciprocable machine tool part, a lever pivotally mounted intermediate its ends having connection with the first mentioned dog-actuated plunger at one end and connection with the latch at the other end, whereby to release the latch when the plunger is actuated by a dog, the spring-actuated plunger upon release of the latch being arranged to move under spring action, and

a pivotally mounted bell-crank lever having the one arm thereof connected with the other dogactuated plunger and the other arm thereof connected with the spring-actuated plunger, said bell-crank lever being arranged upon dog actuation of the plunger to move the spring-actuated plunger in the opposite direction against the spring action.

13. A trip mechanism as set forth in claim 12 wherein the lever connected with the first mentioned dog-actuated plunger has an extension arranged to be operated manually whereby to release the latch at will.

14. A trip mechanism as set forth in claim 12 including a hand lever arranged to move with the bell-crank lever, or to communicate movement to the latter to shift the valve member to start a cycle of movements of the recipr-ocable machine tool part.

15. A trip mechanism as set forth in claim 12 including a hand lever arranged to move with the bell-crank lever, or to communicate movement to the latter to shift the valve member to start a cycle of movements of the reciprocable machine tool part, and means in the nature of another dog on the reciprocable machine tool part arranged at the end of a cycle of movements of said part to engage and move the lever to neutral position.

16. A trip mechanism as set forth in claim 12 wherein the lever connected with the first mentioned dog-actuated plunger has an extension arranged to be operated manually whereby to release the latch at will, and a hand lever arranged to move with the bell-crank lever, or to communicate movement to the latter to shift the valve member to start a cycle of movements of the reciprocable machine tool part.

17. A trip mechanism as set forth in claim 12 wherein the lever connected with the first mentioned dog-actuated plunger has an extension arranged to be operated manually whereby to release the latch at will, a hand lever arranged to move with the bell-crank lever, or to communicate movement to the latter to shift the valve member to start a cycle of movements of the reciprocable machine tool part, and means in the nature of another dog on the reciprocable machine tool part arranged at the end of a cycle of movements of said part to engage and move the lever to neutral position.

JOHN s. BARNES.