US1221476A - Combined safety and throw-off mechanism. - Google Patents

Description

C. F. ROOT. COMBINED SAFETY AND THROW-OFF MECHANISM. 1 APPLICATION FILED MAY 20, I915. RENEWED AUG. 11.!916.

Patented Apr. 3, 1917.

5 SHEETS-'SHE l W1 TNESSES [NVENTOR C. F'. ROOT.

COMBINED SAFETY AND THROW-OFF MECHANISM. APPLICATION FILED MAY 20. 1915. RENEWED AUG. 1|. I916.

1,221,476. Patented Apr. 3,1917.

5 SHEETS-SHEET 2.

[/VVENTUR I c. F'. ROOT. COMBINED SAFETY AND THROW-OFF MECHANISM. 4 APPLICATION FILED MAY 20, I915- RENEWED AUG 11.1916- 1 ,M?@, Patented Apr. 3, 1917.

SHEETS-SHEET 3.

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[NVENTOR A 0' Q, By

h Afforney C. F. ROOT.

COMBINED SAFETY AND THROW-OFF MECHANISM. APPLICATION man MAY 20. 1915. RENEWED AUG. 11.1916.

1,221,4'Y6 Patented Apr. 3, 1917.

5 SHEEZS-SHEET WITNESSES: INVENTOR W% BY Al/omey 1m Nomns vzrrns 1.0.!"070 LIIHIL WASHINKIYON. n c.

C. F. ROOT.

COMBINED SAFETY AND THROW-OFF MECHANISM.

APPLICATION FILED MAY 20. 1915. RENEWED AUG. 1|. 1916..

1,221.4?6. Patented Apr. 3,1917.

5 SHEETS-SHEET 5.

Afforney rrn a rarnnr orient CHARLES E. BOOT, OF RAVENNA, OHIO, ASSIGNOR 0F ONE-FOURTH TO BYRON 0. CONN,

0F MANSFIELD, OHIO.

COMBINED SAFETY AND THROW-OFF MECHANISM.

Application filed. May 20, 1915, Serial No. 29,389.

To all whom it may concern:

Be it known that I, CHARLES F. Roo'r, a citizen of the United States of America, residing at Ravenna, in the county of P0rtage and State of Ohio, have invented certain new and useful Improvements in a Combined Safety and Throw-Oh Mechanism, of which the following is a specification,

This invention relates to a combined safety and throw off mechanism for machines equipped with a moving element and an opposing element which are adapted to act and exert a pressure upon work interposed between said elements, the specific construction of the present invention being more particularly applicable for use in connection with the conventional type of job printing presses.

It is well known that the operation of machines of the class described is highly dangerous to the operators because if by reason of inadvertenee, accident, mistake or otheri'ise the operators fail to remove any part of the person from between the elements or interpose any part of the person between the elements upon the pressure movement of the moving element, before such part of the person is forced in contact with both elements and caught therebetween, then and in that event that part of the operators person will be crushed, injured and maimed by the pressure exerted thereon by the pressure elements.

it is further well known that in the operation ofmachines having a moving or reciprocating element and an opposing element such as printing presses, punch presses, staying machines and the like, the operator must place the hands or fingers between the elements many times in the course of a days operation for the purpose of placing therebctween work to be acted upon by the elements.

To operate machines of the class described for performing the work for which they are adapted, economically, eificiently and to their maximum capacity, they must be run or speeded up so as to leave just sufiicient time for the operator to remove from and place the work between the workengaging elements. It is desirable therefore to provide automatic means operable by contact with the hands or fingers of the operator to Specification of Letters Patent.

Patented Apr. 3, 11917..

Renewed August 11, 1916. Serial No. 114,468.

prevent injury thereto which is operable instantly without the exercise of any mental or physical effort upon the part of the operator.

As the capacity 01' speed of the machine is increased, the liability or danger to the operator of being injured is increased as the operator must interpose his hands or fingers between the work engaging elements oftener and the period of time is shortened in which the operator must place the work between and remove his hands and fingers from between the work engaging elements. It is therefore of the utmost importance in the matter of safety of the operator and the capacity of the machine that the safety operating mechanism shall be automatically operable without any physical or. mental efi'ort upon the part of the operator in the event of his hands or fingers being caught between the elements, such mechanism per mitting the operator to speed up the machine to correspond with the ability of the operator to handle the work without fear of being injured.

The primary object of this invention is to provide controlling means for automatically controlling, and restricting the movement of the movable work engaging element operable upon contact of the controlling means with the fingers or hands of the operator and so locating, arranging and constructing the cont rolling means that when the operator fails to remove his hands or fingers from between the elements or by inadvertence, accident or mistake or otherwise the operators hands or fingers are interposed between the elements, the controlling means will first contact with the fingers or hands of the operator thereby actuating the safety mechanism to prevent the work engaging element from completing its working movement in the direction of the opposing element leaving a pre-determined gap between the elemcnts of sufficient width to permit the hand or fingers to remain therebetween without danger of injury.

Another object is to provide a safety mechanism that can be manipulated by hand periodically at the will of the operator to prevent the work engaging element from exerting a pressure upon the work and to continuously maintain said work engaging element inoperative if desired, thereby comits working movement.

interlocking the driving means tothe workengaging element for movement in unison and means to actuate the driving means to prevent tffrom driv ng the work engaging elem'entto the end'of its working stroke;

said work engaging element being at all times connected to, controlled and governed V by thedriving means thereby eliminating all jar,vibratiompounding or hammering ofthe parts due to the gravity thereof or because of theactuation of the parts for the purpose intended.

The above described objects are set outin myapplication bearing date of March 15, 1915, Serial Number 14AM, and the same objects are common and generic to the present invention.

The present inventiondescribes and claims a different means of accomplishing the above described objects and the preferable specific means employed comprise sliding wedge plates that connect the driving means to the work engaging element'to force the work engaging element to travel to the end of its working stroke under normal conditions and which also is operatedxto prevent it from traveling to the end of its working stroke when the controller which operates the mechanism connected to the sliding wedge plate is subjected 'to resistance or pressure.

A further object is to provide a mechanism that is automatically operable by a controller to impart a sliding movement to the wedge plate when the controller is subjected to pressureor resistance 6. contacts with the hand or fingers of the operator) said mechanism being normally inoperativeto impart movement to'the sliding wedge plate.

.fAnother object is to preferably mount the controller upon pivoted standards and to provide means to maintain the controller inthe path of the elements in a predetermined relation thereto and to permit'the controller to telescope the'platen when the work engaging element acts upon-the work. 7

A further object is to provide means of pressure {upon thecontroller which auto- .inatlca'llyimparts movement to the sllding wedge and thereby prevents the work en-' gaging-{element from traveling to the end of This invention further consists in the utilization of the driving meansfofthe work enga ging element insuch a manner as to QfOrcefa roller carried by it m contact with ax-cam and operate a mechamsm connected to the sliding wedge plate; said mechanism being automatically operable when the controller is subjected to resistance or pressure.

A further object of this invention is to combine a safety device and a throw-off in asingle means.

Another feature of the present invention consists in its ready and easy adaptability and attachment to job presses or the like now in use without any alteration or change thereof.

I attain these and other objects by the mechanism illustrated in the accompanying drawing in which:

Figure 1 is a side elevation of a conventional type of job press showing the combmed safety and throw-off mechanism applied thereto, also showing the position of the parts thereof when the work engaging element is at the end of its idlemovement or about to commence its working movement.

Fig. l, is a cross sectional view on the line mw of Fig. 1.

Fig. 2 is a side elevation of a conventional type r of job press showing the combined.

thereto, also showing the position of the parts thereof when the controller of the mechanism meets with resistance or is subjected to pressure, 11. c. (as shown in the drawings) when the controller contacts with the fingers or hands of the operator.

Fig. 5 is a rear elevation of Figs. 1, 2 and a.

Fig. 6 is a diagrammatic side view partly in section of the sliding wedge plate and end of a link showing the wedge plate in normal position in full lines and in inoperative position in dotted lines.

Fig. 7 is a plan view of Fig. (3.

In the drawing, reference numerals 1 and 2 depict the frame of an ordinary job press, 3 the oscillating bed or work engaging element,4'the oscillating platen, 5 the driving shaft having disks (3 and 7 mounted thereon.

f The disks 6 and 7 carry the usual crank portions 15 and 16 which slidably engage the slots 12 formed in one end of the driving links thereby permitting the driving links to be actuated to impart a variable movement to the work engaging element.

The work engaging element is connected to the driving links by means which under normal conditions drive the work engaging element to the end of its working movement to act upon work interposed between the opposing elements but which under certain conditions is operable to prevent the work engaging element from completing its full working movement, thereby leaving a gap between the opposing elements.

The mechanism for connecting the driving links to the work engaging element are duplicates of each other (except a part of the mechanism operating one of the sliding Wedge plates is preferably dispensed with, as shown in the drawings). The means of connecting one link to the work engaging element therefore, will only be described which is combined, arranged and constructed as follows A pin 17 is fitted to one end of the link intersecting the vertical slot 13 and is held in place by a pin 18. Ears 19 and 20 are provided on the link and pins 21 and 22 fitted thereto.

A plate 23 is provided with a wedge member 24 and two opposed inclined slots 25 and 26 having offset partially circular portions 25 and 26 to seat and lock the pin 17 on dead center with the concentric stud portion 15 of the shaft 14 when the sliding wedge plate is in its normal position. The slots fit over and slidably engage the stud 15 and pin 17, thereby permitting av sliding movement to be imparted to the plate.

The plate 23 is also provided with projecting portions 27 and 28 having- slots 29 and 30 to engage the pins 21 and 22 and guide the plate 23 when it is moved in the vertical slot 13. The sliding wedge plate is normally held in the position shown in full lines in Fig. 6, preferably by a coil spring 31 which forces the large portion of the inclined wedge 24 of the plate 23 between the stud 15 and pin 17 and forcing the pin and stud to seat in the offset portions 25 and 26 thereby connecting the link to the work engaging element to exert a pressure upon work interposed between the elements.

To impart movement to the sliding wedge plate for the purpose of rendering the work engaging element inoperative to perform its work and prevent it from completing its full working movement under certain conditions described hereinbefore and which will be described more particularly hereinafter, the following mechanism is employed A bell crank'32 having a cam 33 on one end and a shouldered end portion 34 on the other end is pivotally attached to the frame work of the press. The bell crank 32 carries a pivoted ratchet dog 35 which is provided with an arm 36 and a handle 37 to provide means of manually rocking the dog. A pawl lever 38 is pivoted to the frame work in juxtaposition to the bell crank, one end having a pawl formation alined with and moving in the path of the teeth 39 of the dog.

A shaft 40 is journaled to the frame work leaving both ends projecting beyond the sides thereof. A bell crank 41 is rigidly secured to the shaft 40, the ends thereof extending in opposite directions. A link 42 is connected to the lower end of the pawl lever and to one arm 43 of the bell crank. The other arm 44 of the bell crank is pivotally connected to the sliding wedge plate by a link 45. An angular locking and releasing lever 46 is pivotally mounted upon the shaft 40 and interposed between the bell. crank 41 and the frame of the press.

A shaft 47 similar to the shaft 40 is journaled to the frame-work of the press, leaving its ends projecting beyond the sides of the framework and preferably located above the shaft 40, as shown in Fig. 5. The vertical portion 48 of the locking and releasing lever is-provided with a horizontal slot 49 which engages the projecting end of the shaft 47 which limits its pivotal movement. A vertical slot or hooked portion 50 is also formed'in the vertical portion 48.

Upright standards 51 and 52 are preferably pivotally secured to the shaft 47 and preferably extend upward beyond the median line of the vertical area of the bed. An angular forwardly extending controller 53 is pivotally jointed or hinged to the free ends of the upright standards 51 and 52 and its pivotal movement is restricted by the pin 54 which engages the slot 55. The controller is yoke shaped to permit it to telescope the platen 4 when the work engaging element is acting or about to act upon the work as shown in Figs. 1 and 2. The controller also carries a roller 56 which is adapted to first come in contact with the fingers or hands of the operator.

The controller preferably extends a considerable distance above the tops of the work engaging elements. A finger bar 57 is pivotally attached to one of the upright standards, 2'. e. 51 and it is provided with an upwardly extending and inclining arm 58. A downwardly extending inclining arm 59 is provided on the controller and its free end contacts with the face of the arm 58 and is yieldingly held in its normal position by the end of the arm 59, engaging the notch 60 in the arm 58.

The end 61 of the finger 57 is preferably formed ball shape and engages the vertical its movement of the bed and platen, a-bracket 62 is rigidly secured to the shaft 47 and it extends toward the rear of the press, its free 'end being providedwith a slot 63 ofirregnl'ar or pro-determined contour. A clamp 64:

' is attached to the leg 65 of the bed and a pin 66 is secured to the end thereof engaging the slot 63. A roller 66" is loosely journaled upon'the crank pin 8 and is alined with and adapted to contactwith the cam 33 of the bell crank 32; I g

The operation of tl1e-safetyand throw-off mechanism is as follows: 7

Referring to Figs. 1 and 2, it will be noted that the shouldered portion 3a of the bell crank 32 is interlocked with the catch block 67' (provided on the locking and releasing lever 48) when the press is operatingnor- .mally and no obstruction is interposed between either of the elements or the controller is not otherwlse sub ected to pressure or re- 7 sistance.

The coil spring 31 under normal conditions exerts its tension to force the largest portion'of the inclinedwedge 24: of the sliding plate 23 between the stud 15 and pin 17,

sliding or forcing the pin '15 to travel to one end of the slot 12 and seat in the offset por-' tion 25" of the slots 25 on dead center with stud 17 which is then seated in the offset portion 26 (as shown in Fig. 6) and thereby driving the work engaging element to the end of its working movement to actupon the work.- l

The controllerisnormally actuated by the movement of the leg 65 of the bed through the medium of the pin 66 of the clamp 64 j which engages and followsthe contour of theslot 63 in the bracket 62 thereby forcing the controller to pivot in the path of theelements and in a pre-determined spaced relation therefrom to permit the operator free andeasy access'to'the platen for the purpose of placing work thereupon until the work engaging element is about to act upon the 'work at which time it telescopes the platen. Referring now to Fig. 4, if an obstruction is interposed between the work engaging element and the controller, as i. e. the hands or' fingers A of the operatoror the controller is otherwise subjected to jpressure, the conv f. V trollerwill'pivotupon its hinge connections '-'disengaging th'e'e'nd of'the arm 59. from its notch and exerting a pressureupon the arm 58 swinging the finger bar 57 which in turn forces the locking and releasinglever' ;,4r's te pivot until the. shaft :47 contacts with" the ,end of the slot 4l9fias shown, thereby re-j leasingthe shouldered portion seer the bell crank 321from the catch block 67 permitting the bell" crank lever 32'to drop by gravity and carrv" the cam 33 toward and in the path vement of the weight 68 whichis provided on the end of the lever 32 and its downward movement is limited by the stop lug 71 which contacts with the pawl lever. When the bell crank lever 32 is released from the catch block 67, it pivots and moves toward the roller 66' and at the same time it carries the ratchet dog 35 over and in the path of pawl lever 38 which engages the teeth 39 of the dog thereby connecting the bell crank lever to the pawl lever which operates the connecting mechanism that is pivotally attached to the sliding wedge plate and as the roller 66' contacts with the cam 33 which is now in its path, it exerts a pressure upon the pawl lever and the mechanism which is connected to the sliding wedge plate thereby forcing the wedge 2a to slide and withdraw from between the pin 17 and the stud 15 as the link is continuing its movement, allowing the stud 15 to move to the end of slot 12 when the controller is resisted and pressure is exerted upon the work engaging element and thereby preventing it from completing its full working movement, and leaving a gap etween the opposing elements.

lVhenthe ratchet dog and pawl lever are engaged, the gap between the elements is maintained continuously and when it is desired to permit the press to again operate normally, the operator manipulates the handle 37 and rocks the ratchet dog disengaging the teeth from the pawl lever and the end of the pawl. lever then. rides over the smooth surface 69 of the dog as shown in Figs. 1 and 2. When the end 3 1- of the bell crank lever is raised, it contacts with the catch 67 forcing the lever 46 to pivot, thereby permitting the end to pass over the catch in position to engage therewith when released. 7

-Excessive pivotal movement of the bell crank 32 is limited in one direction by the shaft 47. A stop pin 70 regulates the backward movement of the dog 35 and receives the thrust of the ratchet dog to impart movement to the bell crank lover. The releasing and locking level it is normally held in the position shown in Figs. 1 and 2 by the weight 72. 7

To use the safety mechanism for a throwoff mechanism, the operator exerts a pressure upon or resists the controller by his hands or fingers at will and the work engaging element is thereby automatically prevented from completing its working movement or exerting a pressure upon the work.

Attention is called to the fact that the d1- mansions or form of the cam 33 can be varied to permit the roller 66 to contact therewith at predetermined points in the movement of the driving link and further that the number. OfLteeth 39 of the ratchet dog can be varied to permit the engagement of the teeth with the pawl lever at different points of the travel of the work engaging elements working movement.

What is claimed is:

1. In a combined safety and throw-off mechanism having a movable work engaging element and an opposing element, driving lneans, means comprising a sliding wedge plate to connect the driving means to the work engaging element to drive and force same to complete its working movement toward the opposing element and exert a pressure upon work interposed between the elements, a controller, and automatic means connected to the controller to actuate the connecting means to prevent the work engaging element from completing its working movement, thereby leaving a gap between the elements when an obstruction extraneous to the work is interposed between the controller and the opposing element.

2. In a combined safety and throw-off mechanism having a movable work engaging element and an opposing element, driving means, means comprising a sliding wedge plate to connect the driving means to the work engaging element to drive and force the same to complete its working movement toward the opposing element and exert a pressure upon work interposed between the elements, a controller, automatic means connected to the controller to actuate the connecting means to prevent the work engaging element from completing its working movement, thereby leaving a gap between the elements when an obstruction extraneous to the work is interposed between the controller and the opposing element, and means to movably maintain the controller in a predetermined relation to the elements.

3. In a combined safety and throw-off mechanism for machines having a movable work engaging element and an opposing ele ment, driving means comprising links having vertical and horizontal intersecting slots, a shaft provided with concentric studs which engage the horizontal slots, pins secured to the driving links in spaced relation from the concentric studs, plates provided with wedge members slidably fitted to the vertical slots, and connecting means to force between and withdraw the wedge members from between the pins and concentric studs of the shaft.-

4. In a combined safety and throw-ofi' mechanism for machines having a movable work engaging element and an opposing element, driving means comprising links having vertical and horizontal intersecting slots, a shaft provided with concentric studs which engage the horizontal slots, pins secured to the driving links in spaced relation from the concentric studs, plates provided with wedge members slidably fitted to the vertical slots, connecting means to force between and withdraw the wedge members from between the pins and concentric studs of the shaft, a

cam secured to the connecting mechanism of the sliding wedge plates, a roller mounted upon the driving means, and a controller automatically operable upon meeting resistance to actuate the connecting mechanism to permit the roller to contact with the cam and thereby arrest the working movement of the work engaging element leaving a gap between the elements.

5. In combination with a pair of work engaging elements adapted to operate upon work interposed therebetween, one of said elements being movable toward the other, driving means connected to the movable element to drive it in unison therewith and to permit movement independent thereof, a sliding wedge plate secured to the driving means, means to automatically operate the sliding wedge plate to drive the movable element to the end of its working movement, a controller, and mechanism connecting the controller and sliding wedge plate which is operable to prevent the movable element from completing its working movement upon the controller being subjected to resistance.

6. In combination with-a pair of work engaging elements adapted to operate upon work placed therebetween, a sliding wedge, driving means connected to one of said elements by said sliding wedge to drive it to the end of its working movement under normal conditions, a mechanism connected to the sliding wedge carrying a cam, and a controller connected to said last mentioned mechanism; said controller being operable when resisted to actuate the mechanism connected to the sliding wedge to prevent the driving means from driving the movable element to the end of its working movement.

7. In a safety mechanism equipped with cooperating pressure elements, one being adapted to move toward the other, driving means yieldingly connected to the movable element, a sliding wedge plate normally coacting with the driving means to drive the movable element to the end of its working movement, and means located in the path of the pressure elements automatically operable by pressure thereon to permit actuation of the sliding wedge plate to prevent the driving means from driving the movable element to the end of its working movement, thereby leaving a gap between the elements.

8. In a safety mechanism for machines equipped with pressure applying elements, one of the elements being movable toward the other, driving means yieldingly connected to the movable element, a sliding wedge plate normally connecting the driving means and movable element to move in unison, a controller, and mechanism connecting the controller and sliding wedge plate operable to prevent the driving means from driving the movable element to the end a trio studs, and means operable by pressure.

of its working movement when the controller is subjected to pressure by an obstruction ,in its path or manually at the will of the f operator. i

. f 9. In: combination with a pairof work engaging elements adapted to operate upon work placed therebetween, driving means yieldingly connected toone of the elements for reciprocating the same, a sliding wedge plate carried by the driving means and normally cor-acting therewith to drive the movableelement to the end of its working movement'to act upon'the work, a controller arranged between the elements, and meanscon- V necting the sliding wedge plate and the coning element having concentric studs which intersect the horizontal slots, pins secured to the driving means in spaced relation from the concentric studs, sliding wedge plates having inclined ,slots with offset portions .fitted to the vertical slot means to normally maintain the offset portion of the inclined slots between, on dead center with each other and in contact with the pins and concenautomatieally or manually'to withdraw the offset portions of the inclined slots from between the pins and concentric studs and out of axial alinement' with each other.

11. In a combined safety and throw-01f mechanism for printing presses and analogous machines, in combination with cooperating pressure elements, means to reciprocalte one of the elements and drive it to the end of its working movement under normal conditions, means'to prevent the driving means from driving the reciprocating elementxto the end of its working movement comprising a controller, and means connecting the controller for permitting the work engaging element to idle at any point in its working-movement, and a cam provided on the connecting means; said cam being adapted to swing in thefpath of the driving means and contact therewith when the controller I is subjected to pressure which causes it to cooperating pressure elements, links having a sliding wedge plate associated therepivot and actuate the connecting means of the driving means. 7 12-,11118, safety mechanism equipped with with and with one of said elements to move said element toward and in juxtaposition to theother, means to normally maintain the sliding wedge plate in locked position and means automatically operable to unlock said sliding wedge plate and limit the travel of the mowibleelement toward the other upon interposition of an extraneous obstruction to the work.

13. In a safety mechanism for machines equipped with pressure applying members, one of the members being movable toward the other, yieldable driving means attached thereto, a sliding wedge plate to connect the work engaging element and driving means for movement in unison and automatically operable to permit of continuously connected, but restricted movement with respect to the driving means.

14c. In a safety mechanism for machines equipped with pressure applying members, one of the members being movable toward the other, yieldable driving means connected thereto, a sliding wedge plate to connect the work engaging element and driving means for movement in unison and to permit of continuously connected, but retarded movement with respect to the driving means, a controller located in the path of the pressure members, and means connected to the sliding wedge plate and to the controller which is operable automatically by an extraneous obstruction to the work or manually by pressure upon the controller.

15. In a safety mechanism for machinery equipped with cooperating members, links, sliding wedge plates continuously associated with one of the members and links to normally move said member toward and in juxtaposition to the other and also automatically operable under abnormal conditions to prevent the movable element from completing its movement in the direction of the opposing member, the driving means and the movable member being always maintained in a continuously connected relation, means to normally maintain the sliding wedge plates in looking position, and means connected to and automatically operable to unlock said sliding wedge plates and permit the movable member to idle without affecting the continuous movement of the links.

16. In a safety mechanism for machines equipped with cooperating pressure members, driving means yieldably connected to onemember, wedging means connecting said member to move it in unison with the driving means toward the other and in juxtaposition therewith under normal conditions, and means automatically operable by an obstruction extraneous to the work, to operate the wedging means to permit the movable member to idle at any point of its working movement but remaining continuously connected and controlled by the driving means while the driving means is moving thereby leaving a gap between the elements.

17. A combined safety and throw olf mechthe work engaging element, wedging means.

constantly associated with the driving means and movable element, a locking means to normally prevent the driving means from yielding, a controller located in the path of the elements, mechanism connecting the controller and wedging means; said controller being operable by an obstruction extraneous to the work to actuate the wedging means to permit the driving means to yield but not stop, and prevent the work engaging element from completing its working movement without stopping.

18. A single safety mechanism which is also adapted for use as a throw off for machines equipped with cooperative pressure elements, driving means yieldingly connected to one of the elements to impart movement thereto which is controlled by the single mechanism, wedging means to connect the movable element to the driving means which permits of continuously connected but varying movement of the movable element toward the opposing element, a controller for the single mechanism located in the path of the elements, said controller being automatically operable by an extraneous obstruction to actuate the single mechanism to operate the driving means and wedging means to restrict but not stop, the movement of the movable element, said single mechanism being also operable manually by pressure at the will of the operator.

19. In a combined safety and throw-ofi mechanism for a machine comprising a movable work engaging element and an opposing element, driving means, means comprising a sliding wedge which is constantly but yieldingly connected to the driving means imparting continuous movement to the work engaging element to drive and force the same under normal conditions toward the working element to exert a pressure upon work interposed between said elements, a controller operable by pressure, and automatic means connected to the controller and actuated by the controller to actuate the driving means to prevent the work engaging element from completing its stroke in the direction of the opposing element, thereby leaving a gap between the elements.

20. In a machine equipped with pressure applying members comprising in combination, a driving means, means yieldingly connected to one of said members and to the driving means to impart movement to one of the said pressure applying members, a controller located in the path of the pressure applying members, means operable by pressure upon the controller to actuate the driving means to gradually shorten the stroke of the moving member during the continuous working movement thereof.

21. In a safety device for machines equipped with pressure applying members, one being movable toward the other, a wedge mechanism, yielding driving means constantly but yieldingly connected to the movable member by said wedge mechanism, a controller, and means operable by the controller to automatically vary and shorten the movement of the movable pressure applying member toward the other as described.

In testimony whereof I aflix my signature in presence of two Witnesses.

CHARLES F. ROOT.

Witnesses JOHN H. Coss, PEARL M. YUNCKER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, 1). G.

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