US1853775A - Dogging and tapering mechanism - Google Patents

Description

April 12, 1932. G. M. PELTON DOGGING AND TAPERING MECHANISM 4 Sheets-Sheet *1 Filed Aug. 11, 1930 gmnnto'a 6'. meg- 704 G. M. PELTON DOGGING AND TAPERING MECHANISM April 12, 1932.

Filed Au fll, 1930 4 Sheets-Shget 2 gww/nto o GYM/ 54 7v auto (M41 April 12, 1932. G. M. PELTON DOGGING AND TAPERING MECHANISM Filed Aug. 11, 1930 4 Sheets-Sheet gmmm T/W/AZ 70 lvllll I April 12, 1932. G. M. PELTON v DOGGING AND TAPERING MECHANISM 4 Sheets-Shet 4 Filed Aug. 11, 1930 f2; a; if

ablkwnu V Patented Apr. 12, 1932 uniransrares enonen ivr. PELTOI-I, on MILWAUKEE, Wisconsin; HERBERT w. knox,nxnouron or PATENT OFFICE SAID GEORGE 1V1. PEL'ION, DECEASED, ASSIGN 310 THE FILER 8a STOWELL OOM- PANY, F MILKVAUKEE, WISCONSIN, A CORPORATION noocrno AND TAPEEING MECHANISM Application filed. August 11, 1930. Serial n. 474,583.

This invention is directed to an improvement in saw m1ll dogging mechanisms where in the dogs are arranged for connected service for cooperation with logs or for coopera'- tion with boards. 7

Saw mill dogs have been heretofore provided for use in a plurality of positions in their projection beyond the face of the knee, such constructions involving means by which the dogs mounted on a frame are designed, through bodily movement of that frame to be projected at selective distances beyond the face of the knee.

A construction of this type involvespower means for moving the frame and thereby the dogs in the selected direction, and incident to the necessity of a movable mounting between the frame and knee and the heavy duty to which the parts are subjected in use, has

proven somewhat unsatisfactory incident to the wear and liabilityof breakage attendant upon the heavy duty requirements.

The primary object of the present 'invention is to mount the frame so-called for vertical reciprocation only with respect to the knee to thereby insure, primarily owing to the absence of the necessity for a movable mounting, that the parts may be made of sufi'icient strength and rigidity in correspondence with the heavy duty requirements.

-A further object is the mounting of the dogs with respect to such frame so that the dogs alone are projected relative to the frame and thereby to the knee to the required selected distances beyond the face of the knee,

the dog operating means providing for a power movement of the dogs to hold them in board-engaging projection beyond the face of the knee and the automatic projection of the the knee will yield under the log impact- I without disturbing the free set relation of the remaining dog or dogs beyond the reach of the log.

Another object ofthe invention is the mounting of the dog frame for vertical reclprocation wlth respect to'theknee, such,

frame moving in fixed path parallel to the face of the knee, withthe provision of power means whereby the frame may bevertically operated to .forcethe dogs into the logor board, the respective dogs being slidably mounted in said frame with their paths of movement in such curved planes as .to permit the dogs to-move inwardly under 10g impact, that is, under a force delivered at right angles or substantially right angles to the face of the knee, while preventing suchinward movement of the dogs under the driving impact of r the dogs necessary to force them into the log or board; v

Still another object ofthe invention is the mounting of the'dogs in'the, frame for move ment along a particular curved path with re' sp-ect to the face of the knee and the provision of power means whereby. the dogs may be selectively moved inwardly with respect to the face of the knee and along such curved paths, and the provision of further means automatically tensioned in the inward movement of the dogs, to projectthem to their maximum or log-engagingposition on the release of such power means.

A further object of the invention is the provision of tapering means for the knee, in which the'knee may be moved relative to the head block for a unit distance taper or for any one of several multiples of such unit distance through the provision of a power mech- 'anism of simple and compact form, which in 7 addition to its tapering function provides for cushioning the movement of the'knee under initial log impact. I i I. The'invention is illustrated in the accompanying drawings, wherein Figure 1 is a side elevation of the knee,

with parts broken away, the improved dogging mechanism'being shown in position.

Figure 2 is a plan View of the same.

Figure 8 is a front elevation of the same, partly broken out.

Figure 4: is a. vertical section through the dog carrying plates and cover plates therefor, the dogs being shown in position.

Figure 5 is a top plan of the same.

Figure dis a side elevation of the dog carrier plates with the dogs in position, the cover plates being omitted.

Figure 7 is a longitudinal section through the power cylinder for operating the dogcarriers and dogs,

The knee, indicated generallyat 1, is of hollow type, the face being formed with an opening 2 extending vertically of the knee through which the dogs project, the face of the'knee on each side of the opening being provided with the usual removable face or wear plates 3. The knee ismounted for sliding movement on the conventional head block 4, the latter being operated by the set works of the usual rack and pinion 5. Thus the knee is mounted for movement by the set works in the initial placement of the knees on the carriage, with each knee mounted for independent taper movements relative to the head block on which it is mounted and independently of'the set works. This construction is conventional and the accepted type in saw mill carriages of this character and needs no further description or explanation Arranged vertically within the knee and secured to one side wall of the knee by bolts '6 is a fixed guide member or bar 7. This guide bar. which is of rectangular form in cross section and which extends from a point near the bottom of the knee to a point substantially above the upper end of the knee, provides the base on which the respective upper and lower dog carriers are'mounted for vertical sliding movement.

The upper dog carrier comprises a plate 8 which overlies and bears against the free face of the guide bar 7 such plate 8 having L-shaped, outstanding edge flanges9 which overlie the edges of the guide bar 7 and er:- tend in rear of the opposite face of the guide bar to thereby slidablv connect theupper dog carrier with the guide bar while preventing other than a sliding movement of such upper dog carrier. The lower dog carrier is similar to the upper dog carrier except with respect to its length, such lower dog carrier comprising a. plate 10 overlying the guide bar 7 and having like L-shaped edge flanges to embrace the sides and rear surface of the guide bar to permit relative sliding movement of the lower dog carrier with respect to, the guide bar. As thus arranged, it is noted that the upper and lower dog carriers are capable of sliding movement vertically of the knee in a predetermined plane and incapable of any other movement with respect to the knee.

The upper dog carrier is here shown as provided with two dogs, the mounting of which with respect to the carrier are substantially identical, and it is to be understood that the invention contemplates the use of a single dog in the upper dog carrier as well as three or more, if desired, though for usual purposes two such dogs have been found suflicient to accommodate the ordinary range of logs encountered in a saw mill. The lower dog carrier support-s but a single dog and such dog constitutes the under dog for the log or board and the space in which this lower. dog operates and its limited range of movement permit the use of but a single dog only.

The upper carrier plate 8 is formed on the face remote from the guide bar 7 with upper and lower dog guides 12. These guides are identical, each comprising a pair of spaced, inwardly and upwardly curved walls 1 and 15,preferably formed as outstanding projections from the plate 8 and defining a curved path between them in which the dog slides; The upper wall 14 of each dog guide extends to the forward edge of the carrier plate, while the lower wall 15 terminates short of the forward edge of the carrier plate. The curved path defined by the walls 14 and 15 which, of course, is the path followed by the dog in moving, extends inwardly and upwa'rdly with respect to the carrier plate and tothe knee, the requirements in this respect being that this curved path must be such as to permit the dog to readily follow it on impact against the dog at right angles to the face of the knee, while preventing the dog from following such curved path on impact of the dog witha log in movement of the dog vertically of the knee. That is to say, the dog must yield and follow its curved path inwardly with respect to the faceof the knee on impact of a 'log with the dog where the log is thrown against the face of the knee, as in placing the log on the carriage, and yet the dog must be withheld from following its curved path of movement under that impact with the log where the dog is driven into the log from above or below and following vertical movement of the dog carrier.

In the particular and peculiar curved path illustrated, it is readily apparent that the dog will yield under endwise impact and will not yield under vertical impact. The lower dog guide 13 is identical in respect to plane of curvature with the upper dog guides, the upper wall 16 of such low'er dog guide 13, however, terminating short of the face of the plate 10, while the lower wall 17 extends to the forward edge of such plate 10.

The upper carrier plate 8 is shown as provided with two dogs 18 and 19which are of identical construction, each slidablycooperatingwithone of the guides 12. The dogs 18 and. 19 have a curvature corresponding to that of the dog guides and terminate at their forward ends in a spike tooth 2O designed for cooperation with logs and in advance of such spike tooth with a similar board tooth 21 of spike form but of materially less di-' mensions than that of the spike tooth, such board tooth beingdesigned forcooperation with the final board of the log. The lower dog 22 is curved to correspond with the curva ture formed by the guide 13 and terminates in a spike tooth 23. The dogs'18 and 19 are provided with threadedvstuds 18,the'heads 19 of which engage shoulders formed by cutting'away the forward guides, thuslimiting the operative movement of the dogs. x

As previously stated, and as will later appear, the dogs are power operated in one direction in their movement with respect to the dog guides and automatically projected inthe opposite direction. As will be plain from the later description, the power operated movement of the dogs is inwardly with respect to the face of the knee, that is,to arrange the dogs in their minimum projection beyond the face of the knee, while the automatic operation of the dogs is in a direction to move the dogs outwardly withrespect to the face of the knee, that is, to their'maxi mum projected position beyond the face of the knee. The means for automatically operating the dogs to their position of maximum projectiOn is identical with the upper dogs 18 and 19 and the lower dog 22.

This means: includes a rod 24 pivotally connected atits upper end above each 'dog I guide to the respective plates 8 and 10, as

indicated at 25, the lower portion of each 3 rod following the curvature of the particu-- lar dogguide and seating in a channel 26 in the lower face of the particular dog with which it cooperates. fixed abutment 27, through which. the rod freely extends, and encircling the rod and bearing between the abutment 27 and the pivot head of the rod is arranged a coil'spring 28. This spring is of suiiicient power to move the dog to a fully projected position, it being evident that when the dog is withdrawn into its dog guide by the power means to be de scribed, the spring 28 of the withdrawn dog or dogs is placed under maximum tension so that on the release of the power the spring acts to immediately project the dogs .to their maximum position. In this connection, it is to be noted that the dogs in their movement toward maximum position under the influence ofthe spring are materially assisted by gravity, for as the dogs are of substantial size, their weight materially assists the power of the spring in projecting the dogs to the desired maximum limit..

The plate 8 of the upper dog carrier is provided with a cover plate 29- to overlie the dogs and provide means for supporting the power operator for the dogs. This cover plate is movably secured tothe plate 8, extends throughout the length thereof, and in the surface next-the-dogsis recessed or. off- In this channel is a set to provide a vertically extending channel 30 in which is slidably mounted a narrow, plate-likedog operator 31. The dog operator 31 is mounted for sliding movement in the channel 30and is formed near its respective ends with elongatedslots 32 into which extend pins 33 carried by the respective dogs 18 and 19. When the dogs are fully proj ected, that is,.at the limit under the influence moving the dog operator or without afiecting the corresponding dog, such independent movement of the dog being permitted by the freedom of its pin 33 in the slot 32in the upward direction; 3

rier is formed on its outer surface to provide upper and lower cylinders 34 and 35. These cylinders are arranged in offset, vertical planes, the upper cylinder terminating about mid-length the cover plate 29, while the lower cylinder extends throughout the length of the plate. A piston 36 is' operative in the upper cylinder 34 and provided with a pistonrod 37 connected through a lateral screw and socket connection 38 with the dog movement of the piston, the dog operator and thereby the dogs are correspondingly moved. 4

operator 31, so that responsive to upward The cover plate 29 is preferably slotted in correspondence with the slots 32 and that of the dog operator 31, such cover plate slots'being indicated at 39, and the pins 33 projecting from the dogs are preferably passed through the cover plate slots, with the heads of such pins beyond the slots to thereby afiorda comparatively broad bearing for these pins and insure the necessary rigidity of the parts.

The plate 10 of the lower dog carrier is provided with a cover plate 40 remov'ably secured to said plate 10 to overlie the dog, said cover plate having an offset, cylindrical hous ing 41 in which operates a piston rod 42 connected by a transverse pin 43 with the lower dog 22. The piston rod 42 extends through the bottom of the cylinder 35 on the cover plate 29 of the upper dog carrier and terminates within said cylinder 35 in a piston '44.

Passage of the piston rod 42 through the bot- 90 v i The cover plate 29 for the upper dog car- Y The upper end of the cover plate 29 for the upper dog carrier has a rearwardly projecting section 45 providing for the connection of the cover plate 29 with a power cylinder, to be later described. This section 45 is also cored longitudinally to provide an air passage 46 whichextends lengthwise the cover plate 29 and communicates with lateral ports 47 and 48 communicating respectively with the lower ends of cylinders 3 and 35. Thus with the terminal of the air passage 46 connected with a source of power as, for example, air under pressure, the admission of such air-under pressure to the passage will simul taneously operate the pistons 36 and 14 and thereby move the upper and lower dogs simultaneously into their withdrawn or inward limit positions, at the same time tensioning the coil springs 28 for the return or the dogs on the release ore'xhaust of the air under pressure.

It is apparent that in the movement of the dogs from the maximum projected position to the minimum projected position, the limit movement of the (log operator for the upper dogsand the contact of the spike tooth 23 of the lower dog with the shortened upper wall 16 of the lower dog guide, that the dogs will be stopped in a predetermined inward position. The limit movement of the dogs in this inward; position is so predetermined that when. at such inward limit ofmovement the spike tooth 20 of the upper dogs is inwardly of the face or wear plates 3 of the knee, while the board tooth 21 of such upper dog is arrangcdbeyond. the plane of such wear plates in position to engage the narrow board with which the dogs are intended at this time to cooperate.

In the inward or withdrawn position of the lower dog, the spike tooth 23 thereof is so arranged that it extends beyond the face of the wear plates 3 to an extent similar to the position of the board teeth oi the upper dog such, for example, as indicated in dotted lines in Figure 6. l/Vhen the dogs are projected to their maximum distance they are, of course, arranged so that the spike teeth of the respective dogs are effective for log-engaging at a point materially in advance of the face of the knee, as indicated in full lines in Figure 6.

A power cylinder 49 is arranged in rear of the dogging mechanism for operating the dog carriers upwardly to a non-dogging relation to the log or downwardly to force the dogs into a dogging cooperation with the log. A piston 50 is operative within the cylinder including a solid portion 51 of a diameter somewhat less than the interior diameter of the cylinder and a skirt portion 52 integral with the solid portion and having an exterior diameter corresponding to a sliding-tit within the cylinc er and-having sealing cooperation with the cylinder through the aidof the usual piston rings 53. The skirt 52 fits overya hollow abutment 54 carried by the bottom of the cylinder, with the upper wall having a central opening 55 A wall 56 depending from the top of the abutment surrounding the opening 55 is formed at its lower end within the abutment with a valve seat 57 closed by a ball valve 58 opening under pressure from beneath but closing under pressure from above.

The cylinder is formed near its lower end with an inlet for air under pressure, indicated at 59, and the wall of the abutment 54 is formed adjacent the bottom of the cylinder with openings 60 to admit air to the space within the abutment and to the cylinder surrounding the abutment. The length of the skirt 52 is such that when the top of said skirt is in contact with the top of the abutment, the extreme lower edge of the skirt is slightly spaced from the bottom wall of the cylinder.

The upper end of the cylinder 49 is provided with a head 61 which extends above the cylinder and has an interior diameter slightly less than that of the cylinder, providing a diameter to snugly receive the solid portion 51 of the piston, the inwardly projecting portion of the head at its lower end being ground to form a seat 62 and the projection of the skirt 52 beyond the solid portion 51 of the piston being similarly ground at 63 to provide a part to cooperate with said seat when the piston is at its extreme upper limit of movement.

The head 61 is provided with an air inlet 64 for air under pressure which leads directly through the head to the interior thereof, this inlet port 64L communicating with an upwardly leading duct 65 in the head which has a lateral port 66 opening to the interior of the head near the upper end thereof. The duct 65 is formed-to provide a valve seat 67' controlled by a valve 68' which freely opens against pressure from beneath but closes under pressure from above. 7

The piston 50 is connected with a piston rod 69 having a diameter somewhat less than the interior of the head but with its diameter in such relation to the diameter of the upper end of the solid portion 51 of the piston as to materially reducethe piston area which may be subjected to pressure from above. Thus it will be apparent that the piston is unbalanced, inthat owingto'the greater area presented at its lower impact surface than at its upper impact surface, the piston will under similar pressures admitted from above and below move upwardly.

The piston rod 69 extends through the head 61 and is connected to the projection or rearwardly extending section 450i the upper cover plate 29 for the upper dog carrier. Thus the upperfdog carrier is reciprocated in the movements of the piston. The lower end of the cylinder 49 is connected to the plate 10.0f the lowerdog carrier so that 01- cylinder 49 permits the use of a single con:

trol valve incident to the unbalanced piston.

For example, the pressure admitted through the port 64 ontothe upper portion of the piston is a constant pressure, while the pressure admitted through the inlet 59 at the bottom of the cylinder is controlled by a single valve. When the pressure is admitted through this inlet 59, the air finds its way through the opening 60 to the interior of the abutment, past the valve 58, through the opening55, and against the lower end of the skirt, which by reason'of the increased area as compared with the upper portion of the piston, causes,

the piston to rise and with it the upper dog carrier. As the piston rises, the solid portion eventually closes the cylinder end of .the inlet port 64- at the upper end of the piston so that r the air in the head above the solid portion 51' of the piston is trapped to serve as an air cushion withits usual function. With the valve controlling the passage of air under pressure to the inlet port 59' at the lower end of the piston open to the atmosphere and cutting ofi the air pressure, a constant pressure at the upper end of the cylinder passes through the upwardly leading duct 65, past the valve 68, and onto the top of the solid portion of the piston and so forces the piston downwardly. As the lower edge of the skirt passes the upper end of the abutment, the air between the skirt and abutment is trapped by the valve 58, thus providing a cushion for the downward movement of the piston. As thus arranged, it is apparent that a single valve only is necessary to control'both movements ofthe piston and that no exhaust other than that for the lower por tion of the piston is necessary, pressure 1'6- 50 maining constantly on the upper side ofthe piston. Thus the control issimplifi ed, the parts respond more readily and qui'ckly,"and there is less wastage of .air under pressure than otherwise. a V I As previously stated, when air is admitted through the air passage 45 and lateral ports 47 and 48 to the cylinders 84: and 35, the upper.

dogs 18 and 19 and the lower dog 22 are moved inwardly to thelimit per 'itted, which movement tends to tension the springs 28 of these dogs and at the same time movethem to such position thatthe board tooth 21 of the upperdogs and the spike tooth 23 of'the lower dog are in that relation to the face of the knee as to provide,- through subsequent vertical operations of the power cylinder 49,

for engaging and holding aboard. .On release of the pressure to the passage 46, the springs 28 operate toproject the dogs to the limit permitted, thus arranging them intheir maximum. projectionbeyond the face ofthe knee so that the spike tooth 20 0f. each upper dog and the spike tooth 23 of the lower dog are in positions toengage and hold a log when operated by the power cylinder-F By providing'aplurality of upper dogs at relatively difierent heights vertically ofthe knee the increased facility of the mechanism for cooperating with logs of large diameter and logs ofsm'all diameter, without an un-' desirable increase in overall height of the parts, is apparent.- l/Vith logs of small di ameter, the intermediate or thelower upper dog may be used, while withlogs of larger diameter: the uppermost upper dog may be brought into play. Thus a comparatively short movement of the upper dog carrier by the power cylinder is necessary under this provision, it beingunderstood that where the uppermost upper dog is used for logs of comparatively large diameter, such log, when in position against-the knee, will of itself move the intermediate or lowermost upper dog inwardly out of the way and without obstructing the movement of the uppermost upper" dog in its log-engaging operation. To this extent, the device automatically accommodates itself to logs of different diameters without necessitating an extreme vertical'dimension of the working parts, as wouldlbe. the casewhere a single dog only was used. claim:- 1; A saw mill dogging mechanism including'a knee, a dog carrier mounted for vertical movement with respectto the knee, a dog mounted for independent movement on said carrier and limited in that movement to a position of maximum projection beyond the face of the'knee in one direction and to a positionof minimum projection beyond the" no face of the knee in the'other directiommeansfor moving the dog to a position of minimum projection beyond the face of the knee, and means for automatically moving the dog to aposition ofmaximum projection beyond the tione'd' means.

face of the knee on release of the first'men-f '2. A dogging mechanism for saw mill Car-j riages including a knee, adog carrlermountedof the power means, said dog being mounted for free movement under log impact froin' the maximum to the minimum position. I

3. A dogging mechanism forsaw mill carriages including a knee, a carrier mounted for reciprocation vertically of'the knee, means for operating the carrier, a dog mountedon the carrier, power means carried by the carrier for moving the dog relative to said carrier to a position of minimum projection beyond the face of the knee, automatic means carried by the carrier for projecting the dog to a maximum position beyond the face of the knee when free to act, the mounting of t the dog on the carrier permitting the dog to move in a power operated direction independently of the power means.

4:. A dogging mechanism for saw mill carriages including a knee,'a carrier. mounted for reciprocation vertically of the knee, means for operating the carrier, a dog mounted on the carrier, power means carried by the car rier for moving the dog relative to said carrier to a position of 'minimum projection beyond the face of the knee, automatic means carried bythe carrier for projecting the dog to a maximum position beyond the face of the knee when free to act, the mounting of the dog on the carrier permitting the dog tomove in a power operated direction independently of the power means, such independent dogmovement subjecting the-dog to the influence of the automatic operating means.

5. Dogging mechanism for saw mill carriages including a knee, a carrier mounted for vertical reciprocation with respect to the knee, a dog mounted on and movable with respect to the carrier, power meansfor mov- T ing the dog relative to said carrier from a maximum projected position to a minimum pro ectedv positlon relative to the face of the knee, and automatic means for moving the dog from aminimum projected position to a means for operating the carrier, a plurality of dogs carried by and movable with respect to-the carrier, power means for simultaneously moving the dogs relative to saidcarrier to a position of minimum projection beyond the face of the knee, and means for automatically moving the dogs to a position of maximum. projection beyond the face of the knee on release of the power means,said dogs beingindependently movable from a position of maximum projection to a position of minimum projection beyond: the face of the knee without regard to the power means.

7. A dogging device for saw mill carriages including a knee, a carrier mounted for reciprocation vertically of the knee, power means for operating the carrier, a plurality of dogs carried by and movable with respect to the carrier, power means for simultaneously moving the dogs relative to said carrier to a position of minimum projection beyond the face of the knee, and means for automatically moving the dogs to a position of maximum projection beyond the face of the knee on release of the power means, each of said dogs being mounted for movement in a curved path so related to the'face of the knee as to permit dog movement under impact in a direction at right angles to the face of the knee and prevent dog movement under impact in a direction parallel to the face of the knee.

8. A dogging device for saw mill carriages including a knee, a carrier mounted for reciprocation vertically of the knee, power means for operating the carrier, a plurality of dogs carried by and movable with respect to the carrier, power means forsimultaneously moving the dogs relative to said carrier to a position of minimum projection beyond the face of the knee, and means for automati callymoving the dogs to a position of maximum projection beyond the face of the knee on release of the power means, each of said dogs being mounted for movement in a curved path so related to the face of the knee as to permit dog movement under impact ina direction at right angles to the face of the knee and prevent dog movement under impact in a direction parallel to the face of the knee, each of the dogs being capable'of movement from a maximum projection beyond the face of the knee to a minimum projection independently of the power means.

9. A doggingmechanism for saw mill carriages including a knee, a dog carrier mounted for reciprocation vertically of the knee, power means for operating the carrier, dogs movable in curved guides arranged on the carrier, a plate connected with the dogs relative to said carrier and acting when operated to move the dogs from av maximum projected position relative to the face of the knee to a minimum projected position, and power means connected to said plate.

10. A dogging mechanism for saw mill carriages including a knee, a dog carrier mounted for reciprocation vertically of the knee, powermeans for operating the carrier, dogs movable in curved guides arranged on the carrier, a plate connected with the dogs and acting when operated to move the dogs relative to said carrier from a maximum projected position relative to the face of the knee to a minimum projected position, power means connected to said plate, and automatic dog operating means tensioned in the operative movement of the plate to move the dogs from .minimum projected position beyond the face of the knee to maximum projected position when said automatic means is free to act.

11. A dogging device for saw mill carriages including a knee, a carrier mounted for reciprocation vertically of the knee, power means for operating the carrier, a plurality of dogs carried by and movable with respect to the carrier, power means for simultaneously moving the dogs relative to said carrier toaposition of minimum projection beyond the face of the knee, and means for automatically moving the dogs to a position of maximum projection beyond the face of the knee on release of the power means, each of said dogs being mounted for movement in a curved path so related to the face of the knee as to permit dog movement under impact in a direction at right angles to the face of the knee and prevent dog movement Qunder impact in a direction parallel to the face of the knee, each of the dogs being capable of movement from a maximum projection beyond the face of the knee to a minimum projection independently of the power means, the connection between the dogs and plate permitting independent movement of the dogs from a maximum to a minimum position of projection beyond the face of the knee when the plate is in inoperative posi-' tion.

12. A dogging mechanism for sawmill can riages including a hollow knee, a guide ar ranged within the knee and extending vertically thereof, upper and lower carriers slidably mounted on said guide, power means for operating said carriers, an upper dog mounted for iii-ovement in a curved path on and with respect to the upper carrier, a lower dog mounted for movement on and in a curved path with respect to the lower carrier, an operating plate connected to the up:

per dog and movable on the upper carrier, a cover plate for each carrier, a power means including a cylinder and a piston mounted on the cover plate, a connection between said piston and said operating plate, a second power means mounted on the cover'plate and including a cylinder and a piston, a connection between said piston and said lower dog, and means for simultaneously admitting fluid under pressure to the cylinders of the respective power means, said power means moving the dogs from a position of maximum projection beyond the face of the knee to a position of minimum projection.

13. A dogging mechanism for saw mill carriages including a hollow knee, a guide arranged within the knee and extending vertically thereof, upper and lower carriers slidably mounted on said guide, power means for operating said carriers, an upper dog mounted for movement in a curved path on and with respect to the upper carrier, a lower dog mounted for movement on and in a curved path with respect to the lower carrier, an operating plate connected to the upper dog and movable on the upper carrier, a cover plate for each carrier, a power means including a sure to the cylinders of the respective power means, said power means moving the dogs from'a position of maximum projection beyond the face of the knee to a position of minimum projection, and means mounted on the respective carrlers and tensioned 1n the power operated movement'of the dogs to move'said dogs from a minimum projected position beyond the face of the knee to a maximum projection beyond the knee when free to act.

a 14:. A dogging mechanism for saw mill cariages including a hollow knee, a guide arranged within the knee and extending vertically thereof, upper and lower carriers slidably'mounted on'said uide, power means vfor operating said carriers, an upper dog mounted for movement ina curved path on and with respect'to the upper carrier, a lower dog mounted for movement on and in a curved path with respect to thelower carrier, an operating plate connected to the upper dog and movable on the upper carrier, a cover plate for each carrier, a power means including a cylinder and a piston mounted on the cover plate, a connection between said piston and said operating plate, a second power means mounted on the cover plate and including a cylinder and a piston, aconnection between said piston and said lower dogmeans for simultaneously admitting fluid under pressure to the cylinders of the respective power means, said power means moving the dogs from a position of maximum projection beyond the face of the knee to a position of minimum projection, and means mounted on the respective carriers and tensioned in the power operated movement of the dogs to move said dogs from a minimum projected position beyond the face of the knee to a maximum projection beyond the face of the knee when free to act, the upper dog beingmounted for free movement with respect to the operating plate and independently of the power means under predetermined end impact on the dog.

15. Dogging mechanism for saw mill carface of the riages including a hollow knee, a guide mounted vertically within said knee, upper andlower dog carriers slidably cooperating Y with said guide, power means for moving the respective carriers, curved guideways on the upper carrier, a curved guideway on the lower carrier, dogs mounted in each of said guideways for sliding movement with respect thereto, an operating plate connecting the upper dogs for simultaneous'movement in one direction, each of the dogs being connected to the plate to permit independent movement of the dogs in the same direction, means connected to each of tee dogs for automatically projecting the dog to a log-engaging position beyond the face of the knee, a cover plate for the upper carrier, a cover plate "for the lower carrier. a plurality of cylinders arranged on the cover plate for the upper car rier, a piston in each of said cylinders, 21 connection. between one oi? the pistons and the o )erating plate, :1 connection between the other of said pistons and the dog on the lower carrier, means for simnltmieously admitting fluid under pressure to said cylinders, a power cylinder -'ncluding a piston connected to the upper carrier, a connection between said cylindex and the lower carrier, means for admitting fluid under pressure beneath the cylinder of said lastnamed power means to raise the upper carrier and thereby the dogs connected thereto, and means for admitting power to the cylinder of the last named power means to initially move the upper carrier and the dog carried thereby downwardly and thereafter move the lower carrier and the dog carried thereby upwardly.

In testimony whereof I afliX my signer ture.

GEORGE M. PELTON. [n s]

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