US1220787A - Stop-motion. - Google Patents

Description

J. REESE.

STOP MOTION. APPLICATION FILED SEPT- 13. l9l6.

Patented Mar. 27, 19 17.

2 SHEETS-43M I.

KYMMC Lg Any 5.

J. REECE.

v swan/10mm, APPLICATION FILED SEPT- 13 1916.

1 2 Patented'Mar.27,1917.

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Inventor. vJohn Reece by R J Kumwb & CMWI, n s.

JOHN REECE, OF MANCHESTER, MASSACHUSETTS.

STOP-MOTION.

meanest.

Specification of Letters Patent. Patentgd Mar, 27, 1917,

Application filed September 13, 1916. Serial No. 119,798.

To all whom it may concern:

Be it known that I, JOHN Rnnon, a citizen of the United States, residing at Manchester, in the county, of Essex and State of Massachusetts, have invented certain new and use ful Improvements in Stop-Motions, of which the following is a specification, reference being had therein to the accompanying draw- 1119:.

This invention relates to stop motions, such for example as are adapted to be employed in connection with high speed power driven machines of various kinds;

The main object is to afiord an efficient and smooth working stop motion .adapted to promptly bring to a stop the shaft in question without substantial or objectional shock and in a substantially definite final shaft position.

Another object is to provide a stop motion wherein no reliance is placed upon mere friction as a retarding means,'butin which the driven or rotated parts are slowed down by a. mechanical restraining operation which takes place in a definite manner so as to progressively remove the destructive power or energy, this action preferably continuing until the energy and motion are reduced to a point sufficiently low to obviate a destructive or objectionable shock, so that, after the discontinuance of the retarding action, the shaft may be stopped by suitable means in the required final angular position.

A further object is to accomplish the desired results by a species of reaction between the constantly rotating power parts and the driven or rotated parts during the period of slowing down while stopping.

Other and more detailed objects will be elucidated in the hereinafter following description or will be apparent to those skilled in the art.

To the accomplishment of the above rcferred to objects the present invention consists in the novel stop motion, combinations, mechanisms, arrangements, devices and details herein illustrated, described, referred to or claimed.

The accompanying drawings illustrate one form in which the principles of the present invention may be embodied. Figure 1 is a front elevation of a stop motion embodying the present invention, the parts being shown in their normal running condition, this view being partly in section on the plane 11 of Fig. 2.

Fig. '2 is a left elevation of the parts shown in Fig. 1.

Fig.3 is a vertical section on the plane 33 of Fig. 2.

Fig. 4 is a similar section on the plane 4E4= of Fig. 2.

Fig. 5 is a modification shown in front view of certain parts of Fig. 1. v In addition to the various fixed frame parts or brackets 10, the illustrated mechanism comprises what may be termed constantly rotating power parts which continue to rotate when the machine itself is brought to av stop; driven parts adapted to be rotated by the power parts during the normal running of the machine and to be disengaged therefrom when the machine is stopped; and the mechanism or stop motion by which the driven parts are brought to rest promptly, without substantial shock, and in a definite final position.

Generally speaking, the stop motion parts comprise what may be termed a crank d,evice associated with the driven parts, and what may be termed a grip device associated with one of the constantly rotating power parts, together with connections between the grip device and crank device whereby the reaction previously referred to is brought about and the driven parts are caused to be slowed down by mechanical restraint.

By the term crank device I intend to include anything in the nature of a revolving crank or arm turning with the rotating driven parts, such, for example, as the ordinary eccentric, upon which pressure or restraint may be imposed when the parts are turning under momentum so as to bring about a slowing down. By a grip device I have reference to any sort of device which normally is inefiective, but which, like a tooth or pawl or wedge, may at the proper time be caused to grip or engage with a rotating power part, so that the latter may have some control or restraint over the grip device. Thus, the ordinary pawl and toothed ratchet may be the grip device.

The principle of the present mechanism the crank device cause a progressively in-' creasing restraint on the latter, terminating with a disengagement of the connections or grip device when the latter has reached its dead center position,*so that in a gradual and shockless manner the driven parts are compelled to slow down, being then left free to rotate. by momentum for a fraction of a'rotation until the final impact or other stoppage, which will be without substantial shock.

In the illustrated mechanism the constantly rotating power parts include a pulley'12, which may be supposed to be rotated by a power belt. This pulley at its interior is provided with a conical clutch surface 13 adapted to be engaged by a complementary clutch member 14.

The power pulley 12 is shown mounted on a power sleeve 14 this structure being adapted to permit the driven shaft to be located Within the sleeve, and therefore in axial alinement with the driving parts. Suitable collars hold the rotating power sleeve 14 in proper relation to its bearing 15.

The described parts 12 and 14 constitute the entire power parts which are shown in the drawings, and these are the only parts which constantly rotate, with the exception of the following, whose function, in connection with the stopping action, will be later described. On the power sleeve is fixed a gear 16 engaging a gear 17 on a countershaft 18, which counter-shaft has fixed bearings 19, 19, and at a suitable point has fixed to rotate with it a toothed ratchet wheel 20. All of these described parts are constantly power driven. All other rotary parts hereof are stopped by the stop motion.

Having thus referred to the power parts, I will describe the connections by which the driven shaft 21 is normally driven at its full speed during the stitching or other operation of the machine. For this purpose the cone clutch 13, 14, is employed, the member l4being splined to the driven shaft so as to rotate therewith, while being capable of sliding axially. A grooved collar 22, secured to the clutch cone 14, is engaged by the opposite studs of a yoked clutch arm 23. Thefulcrum at the upper end of the clutch arm 23 is afiorded by a rock shaft 24,'from whichextends a second arm 25, and from the extremity of the arm 25 may extenda' link 26 to any suitable location, so as to give the operative control and permit the engagement or disengagement of the clutch 13, 14. Pushing down on the link 26 disengages the clutch.

As will appear, the present stop motion is preferably such that, when the operating link 26 is thrown down to disengage the clutch, its action automatically puts the stop motion into operation; that is to say, the swinging of the clutch arm 23 effects both the disengagement of the power and the application of the stop motion.

The stop motion grip device consists of the ratchet wheel 20, before mentioned, which rotates constantly, and a cooperating pawl 27 arranged to oscillate about the shaft 18 as a center, and during the'stopping action to engage with the ratchet for the purposes mentioned. The pawl 27 is carried at the extremity of an oscillating arm 28, which has a slotted downward extension 29 for purposes that will be later explained. The pawl is so mounted on its carrying arm 28 that it may normally be held out of engagement with the ratchet, but during the stopping action may come into engagement and action.

The pawl 27 is pivoted at 30 to the oscillating carrier 28, and a spring 31 tends to hold the pawl in engagement with the ratchet. Normally during the running of the machine the pawl is held out of engagement, and for this purpose it is provided with a contact pin 32, which, as the pawl oscillates, runs around the surface of an arc-shaped wedge or cam 33. When the wedge cam 33 is held to the right as in Fig. 2 the pawl is held inoperative, as seen in Fig. 1.

This condition of affairs is maintained normally by connections between the arm 34, which carries the wedge cam, and the clutch arm 23. A short headed rod 35 extends from the clutch arm through an opening in the arm 34. By this arrangement, when the clutch 13, 14, is held closed, as in Fig. 2, the lower end of arm 34 is held to the left and the pawl is inoperative. A compression spring 36 is arranged between the arms 34 and 23, so that, when the clutch is open, the arm 34 tends to swing so as to permit the pawl to become operative.

This action, however, is permitted to take place only at a predetermined angular position of the driven shaft, so that the stopping action may not prematurely commence. For this purpose a pivoted guard or finger 37 is arranged at the lower end of the arm 34 to cooperate with a rotating cam or guard 38 on the driven shaft, as seen in Fig. 3. When the shaft has turned to the position indi- It should be explained that the figures 1 a show the parts in the position at which the pawl may become operative if it be as sumed that the clutch 13, 14 is disengaged.

As long as the driven shaft is rotating, the pawl 27 oscillates over a fixed path, but at non-uniform speed. During the stopping action a peculiar cotiperation. occurs between the pawl and the ratchet, which will be later explained. I will first explain the connections for oscillating the pawl over its fixed range of action.

For this purpose the carrying arm 28 and its extension 29 are oscillated around 'the counter-shaft 18 as a center. This oscillation is effected from the driven shaft 21 by means of a member 39, which may be termed a crank device. This is secured to the driven shaft by a key, so that the crank travels around and around as long as the shaft rotates. The extremity of the crank 39 is connected by a block and pivot device with the slotted extension 29 of the pawl carrying arm. This device comprises a block 40, which is slidable in the slot of the extension 29 and is engaged by a pivot stud 41 with the crank 39, so that, as the crank travels around and around, the carrier arm is oscillated to and fro. At the right and left sides of Fig. 1 are shown in full lines and dotted lines the extreme positions of swinging of the extension 29. screw adjusting device 42 may be employed to regulate the effective length of the crank arm 39 by adjusting the position of the pivot stud 41 thereon, and this adjustment enables regulation of the critical speed, or speed at which the driven shaft is left rotating freely prior to the final impact or. stoppage.

In order to reduce vibration, the crank device 39 is shown as provided with a dia metrically opposite extension 43, and for convenience 1 have formed on the face of the extension a projection or rotating impact stop 44.

As has been before explained, the general principle of action of the present stop motion is that a retarding effect is imposed on the driven shaft through the pawl 27, which becomes inoperative at a predetermined point, leaving the driven parts to ad vance under small momentum. The final stoppage in a definite angular shaft position might be'efl'ected in various ways, but I prefer an impact stop, and for this purpose I provide a non-rotating stop dog 45, arranged to coiiperatewith the rotating dog or projection 44.

The stop dog 45 is fitted slidably in the frame 10 and connected, so that normally it stands out of the path of the dog 44, as seen in Fig. 2. This is effected through an extension 46 of the clutch lever 23. The left end of the dog 45 is provided with a headed bolt 47 passing through a hole in the extension 46. By this arrangement, as long as the clutch is closed, the clutch lever holds the dog 45 to the left out of the path of the rotating dog. When the clutch is disengaged, the clutch lever efiects the compression of a spring 48, which tends to throw the dog 45 into the path of the dog 44. This, however, it is not permitted to do until the proper time in the sequence of actions, being held to the left by a guard device consisting of a pivoted guard finger 49 mounted on the dog 45 and a rotating guard or cam 50 secured to the driven shaft. When the guard members 49, 50, have reached the position indicated in Fig. 4, the dog 45 may assume effective position, assuming that the clutch has been opened.

The cotiperation between the pawl 27 and the uniformly rotating ratchet 20 will now be explained. The general principle of the action is that, during a certain period of time in the sequence of stopping actions, the pawl and the :parts connected with it are restrained and caused to move uniformly with the ratchet, rather than accelerating, as they would otherwise do. To explain the action I have drawn three radii 51, 52, 53, on Fig. 1. It will be observed that, when the crank 39 stands on the radius 51, its effect on the pawl carrying arm is at a minimum. When the crank is on the radius 52, its operative effect on the pawl carrier is maximum. This isnot only by reason of the fact that the crank is at the most effective part of its stroke, but also because at this time the pivot 41 has slid close to the counter-shaft 18, thus reducing the efiective length of the arm 29 to a minimum. We, therefore, have the condition that, when the crank is passing from radius 51 to radius 52, it tends to accelerate the swinging movement of the pawl and carrier from a minimum to a maximum. In the normal running of the machine it actually has this efi'ect, the pawl then being held out of contact with the ratchet, as seen in Fig. 1. After the crank passes the radius 52, it no longer tends to accelerate, but to progressively reduce, the speed of the pawl. The

stop dogs 44 and 45 are arranged to impact when the crank 39 has reached the radius 53.

In. the stopping action of the mechanism the crank is precluded from accelerating the curved movement of the pawl, because the pawl, having dropped into engagement with the ratchet, is limited against advancing at any greater speed than the constant and uniform speed of the ratchet. The result is a reaction by the constantly rotating power parts, including the ratchet 20 through the pawl 27, upon the driven parts, including the crank 39 and shaft 21, such that, as the crank passes from radius 51 to radius 52, it is constrained to slow down proportionately to its tendency to accelerate the pawl.

sarily ceases and leaves the driven shaft ro- V tating at a comparatively low rate of speed, having negligible momentum. Shortly afterward the final stop dogs impact each other, and the sequence of stopping movements is completed.

When the controlling link or clutch lever is thrown to start the machine, the parts are restored and the pawl is disengaged from the ratchet, so that the cone clutch may effectively drive. The sequence of events on disengaging the clutch may be briefly restated as follows: The shifting of the clutch lever opens the clutch. At the same time the clutch lever compresses the springs 36 and 48. The arm 34 and the dog 45, however, maynot move into their effective positions unless or until the guarding cams 38 and permit. At the proper point in rotation the two guards assume. the positions shown in Figs. 3 and 4, respectively. -Simultaneously the dog 45 jumps into the path of thedog 44, and the arc-shaped wedge cam 83 moves from the pawl 27 so as to permit the pawl to drop into engagement with the ratchet. At this stage ofoperations the pawl carrier isin the Fig. 1 position and is commencing to travel to the right. The described cooperation between the crank 39 and the carrier arm tends to accelerate the pawl movement, but the ratchet prevents and-holds it to a uniform speed, thus retarding the crank 39 and the driven shaft. When the crank reaches its upright position along the radius 52, the tendency to accelerate ceases and the ratchet no longer restrains the pawl, but advances freely beneath the pawl. This period lasts only momentarily, upon which the dog 44 strikes the dog 45. e

In the modification shown in Fig. 5 the extension29 of the pawl carrier 28 is made of afspecial curved shape such that the block and pivot. device 40, 41, has a longer range of action, in the neighborhood of 90, rather than 459, so that the rate of retarding of the driven shaft is rendered less abrupt, thus easing the stopping action.

It will thus be seen that a stop motion has been described operating according to the principles and attaining the objects and advantages of the present improvement. Since. many matters of combinations, arrangement, design and detail may be variously altered or modified without departing from the underlying principles, no limitation to such features is intended except in so far as set forth in the appended claims.

What is claimed is:

1. A stop motion comprising in combination with the constantly rotating power parts .and the rotary driven parts to be creasing speed until a slow speed is secured having harmless energy.

3. A stop motion comprising in combination with the constantly rotating power parts, and the rotary driven parts to be stopped, reciprocating means adapted to be put into effect when the driven parts are rotating under momentum whereby a power part is caused to exert restraint against the rotation of the driven parts, to hold back the rotation thereof with a progressively (lecreasing speed until a slow speed is secured having harmless energy, and a stepping means adapted to finally stop the driven parts in a definite position.

4. A stop motion comprising in combination with the constantly rotating power parts, and the rotary driven parts to be stopped, reciprocating means adapted to be put into effect when the driven parts are rotating under momentum whereby a power part is caused to exert restraint against the rotation of the driven parts, the same including a toothed ratchet constantly driven from the power parts, a reciprocable pawl adapted to engage the ratchet during stoppage, and connections from the driven parts tending to accelerate the pawl, whereby the restraint of the ratchet upon the pawl progressively retards the driven parts.

5. A stop motion comprising in combina- 1 tion with the constantly rotating power parts, and the rotary driven parts to be stopped, reciprocating means adapted to be put into eifect when the driven parts are rotating under momentum whereby a power part is caused to exert restraint against the rotation of the driven parts, including a crank device rota-ting with the driven parts, a grip device mounted eccentrically to the driven parts, and connections from the power parts operative through the grip device to react upon the driven parts to retard rotation.

6. A stop motion comprising in combination with the constantly rotating power parts, and the rotary driven parts to be stopped, a crank device rotating with the driven parts and through which restraint may be imposed for the stoppage thereof, and connections adapted to be rendered operative for the purposes of stopping, whereby a power part temporarily operates to restrain the driven part speed progressively.

7. A stop motion comprising in combination with the constantly rotating power parts, and the rotary driven parts to be stopped, a grip device normally inoperative but adapted to be operatively engaged with a power part during a portion of a rotation "during stoppage, and connections from said grip device for progressively restraining the driven parts. m

8. In combination, constantly rotating Uopies of this patent may be obtained for power parts, driven parts adapted to be rotated by and disengaged from said power parts, said driven parts including a crank device, and means for stopping the driven parts including a grip device adapted to engage a rotating power part for a portion of a rotation, and connections between said grip device and said crank device whereby the driven parts are slowed during the part rotation of said grip device.

In testimony whereof, I have aflixed my signature hereto.

JOHN REEOE.

five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

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